Search results for: flexure-based spring mechanisms

Authors: Hassan Saffari;, Reza Askari Moghadam

Abstract:

In modern communication systems, it is highly demanded to achieve high performance with minimal power consumption. Low actuation voltage RF MEMS (Micro-Electro-Mechanical Systems) switches represent a significant advancement in this regard. These switches, with their ability to operate at lower voltages, offer promising solutions for enhancing connectivity while minimizing energy consumption. Microelectromechanical switches are good alternatives for electronic and mechanical switches due to their low insertion loss, high isolation, and fast switching speeds. They have attracted more attention in recent years. Most of the presented RF MEMS switches use electrostatic actuators due to their low power consumption. Low actuation voltage RF MEMS switches are among the important issues that have been investigated in research articles. The actuation voltage can be reduced by different methods. One usually implemented method is low spring constant structures. However, despite their numerous benefits, challenges remain in the widespread adoption of low-actuation voltage RF MEMS switches. Issues related to reliability, durability, and manufacturing scalability need to be addressed to realize their full potential in commercial applications. While overcoming certain challenges, their exceptional performance characteristics and compatibility with miniaturized electronic systems make them a promising choice for next-generation wireless communication and RF applications. In this paper, some previous works that proposed low-voltage actuation RF MEMS switches are investigated and analyzed.

Keywords: RF MEMS switches, low actuation voltage, small spring constant structures, electrostatic actuation

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Authors: Saltanat Zhilkibayeva, Muratulla Utenov, Nurzhan Utenov

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The distributed inertia forces of complex nature appear in links of rod mechanisms within the motion process. Such loads raise a number of problems, as the problems of destruction caused by a large force of inertia; elastic deformation of the mechanism can be considerable, that can bring the mechanism out of action. In this work, a new analytical approach for the definition of internal forces in links of robotic systems and mechanisms with statically indeterminate and determinate structures taking into account the distributed inertial and concentrated forces is proposed. The relations between the intensity of distributed inertia forces and link weight with geometrical, physical and kinematic characteristics are determined in this work. The distribution laws of inertia forces and dead weight make it possible at each position of links to deduce the laws of distribution of internal forces along the axis of the link, in which loads are found at any point of the link. The approximation matrixes of forces of an element under the action of distributed inertia loads with the trapezoidal intensity are defined. The obtained approximation matrixes establish the dependence between the force vector in any cross-section of the element and the force vector in calculated cross-sections, as well as allow defining the physical characteristics of the element, i.e., compliance matrix of discrete elements. Hence, the compliance matrixes of an element under the action of distributed inertial loads of trapezoidal shape along the axis of the element are determined. The internal loads of each continual link are unambiguously determined by a set of internal loads in its separate cross-sections and by the approximation matrixes. Therefore, the task is reduced to the calculation of internal forces in a final number of cross-sections of elements. Consequently, it leads to a discrete model of elastic calculation of links of rod mechanisms. The discrete model of the elements of mechanisms and robotic systems and their discrete model as a whole are constructed. The dynamic equilibrium equations for the discrete model of the elements are also received in this work as well as the equilibrium equations of the pin and rigid joints expressed through required parameters of internal forces. Obtained systems of dynamic equilibrium equations are sufficient for the definition of internal forces in links of mechanisms, which structure is statically definable. For determination of internal forces of statically indeterminate mechanisms (in the way of determination of internal forces), it is necessary to build a compliance matrix for the entire discrete model of the rod mechanism, that is reached in this work. As a result by means of developed technique the programs in the MAPLE18 system are made and animations of the motion of the fourth class mechanisms of statically determinate and statically indeterminate structures with construction on links the intensity of cross and axial distributed inertial loads, the bending moments, cross and axial forces, depending on kinematic characteristics of links are obtained.

Keywords: distributed inertial forces, internal forces, statically determinate mechanisms, statically indeterminate mechanisms

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Authors: Wenxue Xu

Abstract:

Fluid resistance damper is an important damping element to attenuate vehicle vibration. It converts vibration energy into thermal energy dissipation through oil throttling. It is a typical fluid-solid-heat coupling problem. A complete three-dimensional flow-structure-thermal coupling dynamics simulation model of a gas-filled fluid-resistance damper was established. The flow-condition-based interpolation (FCBI) method and direct coupling calculation method, the unit's FCBI-C fluid numerical analysis method and iterative coupling calculation method are used to achieve the damper dynamic response of the piston rod under sinusoidal excitation; the air chamber inflation pressure, spring compression characteristics, constant flow passage cross-sectional area and oil parameters, etc. The system parameters, excitation frequency, and amplitude and other excitation parameters are analyzed and compared in detail for the effects of differential pressure characteristics, velocity characteristics, flow characteristics and dynamic response of valve opening, floating piston response and piston rod output force characteristics. Experiments were carried out on some simulation analysis conditions. The results show that the node-based FCBI (flow-condition-based interpolation) fluid numerical analysis method and direct coupling calculation method can better guarantee the conservation of flow field calculation, and the calculation step is larger, but the memory is also larger; if the chamber inflation pressure is too low, the damper will become cavitation. The inflation pressure will cause the speed characteristic hysteresis to increase, and the sealing requirements are too strict. The spring compression characteristics have a great influence on the damping characteristics of the damper, and reasonable damping characteristic needs to properly design the spring compression characteristics; the larger the cross-sectional area of the constant flow channel, the smaller the maximum output force, but the more stable when the valve plate is opening.

Keywords: damper, fluid-structure-thermal coupling, heat generation, heat transfer

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Authors: Lamiche Chaabane

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In this study, a new method for solving sequence alignment problem is proposed, which is named ITS (Improved Tabu Search). This algorithm is based on the classical Tabu Search (TS). ITS is implemented in order to obtain results of multiple sequence alignment. Several ideas concerning neighbourhood generation, move selection mechanisms and intensification/diversification strategies for our proposed ITS is investigated. ITS have generated high-quality results in terms of measure of scores in comparison with the classical TS and simple iterative search algorithm.

Keywords: multiple sequence alignment, tabu search, improved tabu search, neighbourhood generation, selection mechanisms

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Authors: Nahed Mohamed Ismail, Bayomy Mostafa, Ahmed Abdel Kader, Ahmed Mohamed Azzam

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Effect of lining watercourses on the distribution and abundance of fresh water snails at two Egyptian governorates, Baheria (new reclaimed area) and Giza was studied. Seasonal survey in lined and unlined sites during two successive years was carried out. Samples of snails and water were collected from each examined site and the ecological conditions were recorded. The collected snails from each site were placed in plastic aquaria and transferred to the laboratory, where they were sorted out, identified, counted and examined for natural infection. The size frequency distribution was calculated for each snail species. Results revealed that snails were represented in all examined watercourses (lined and unlined) at the two tested habitats by 14 species. (Biomphalaria alexandrina, B. glabrata, Bulinus truncatus, Physa acuta. Helisoma duryi, Lymnaea natalensis, Planorbis planorbis, Cleopatra bulimoids, Lanistes carinatus, Bellamya unicolor, Melanoides tuberculata, Theodoxus nilotica, Succinia cleopatra and Gabbiella senaarensis). During spring, the percentage of live (45%) and dead (55%) snail species was extremely highly significant lower (p>0.001) in lined water bodies compared to the unlined ones (93.5% and 6.5%, respectively) in the examined sites at Baheria. At Giza, the percentage values of live snail species from all lined watercourses (82.6% and 60.2%, during winter and spring, respectively) was significantly lower (p>0.05 & p>0.01) than those in unlined ones (91.1% and 79%, respectively). Size frequency distribution of snails collected from the lined and unlined water bodies at Baheria and Giza governorates during all seasons revealed that during survey, snail populations were stable and the recruitment of young to adult was continuing for some species, where the recruits were observed with adults. However, there was no sign of small snails occurrence in case of B. glabrata and B. alexandrina during autumn, winter and spring and disappear during summer at Giza. Meanwhile they completely absent during all seasons at Baheria Governorate. Chemical analysis of some heavy metals of water samples collected from lined and unlined sites from Baheria and Giza governorates during autumn, winter and spring were approximately as the same in both lined and unlined water bodies. However, Zn and Fe were higher in lined sites (0.78±0.37and 17.4 ± 4.3, respectively) than that of unlined ones (0.4±0.1 and 10.95 ± 1.93, respectively) and Cu was absent in both lined and unlined sites during summer at Baheria governorate. At Giza, Cu and Pb were absent and Fe were higher in lined sites (4.7± 4.2) than that of unlined ones (2.5 ± 1.4) during summer. Statistical analysis showed that no significant difference in all physico-chemical parameters of water in lined and unlined water bodies at the two tested habitats during all seasons. However, it was found that the water conductivity and TDS showed a lower mean values in lined sites than those of unlined ones. Thus, the present obtained data support the concept of utilizing environmental modification such as lining of water courses to help in minimizing the population density of certain vector snails and consequently reduce the transmission of snails born diseases.

Keywords: lining, fresh water, snails, watercourses

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Authors: Frank Boris Feutmba Keutchou, Saurelle Fabienne Bieghan Same, Verelle Elsa Fogang Pokam, Charles Ursula Metapi Meikeu, Angel Marilyne Messop Nzomo, Ousman Tamgue

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Infectious diseases are one of the most important causes of morbidity and mortality worldwide. These diseases are caused by micro-pathogenic organisms, such as bacteria, viruses, parasites, and fungi. Heritable changes in gene expression that do not involve changes to the underlying DNA sequence are referred to as epigenetics. Emerging evidence suggests that epigenetic mechanisms are important in the emergence and progression of infectious diseases. Pathogens can manipulate host epigenetic machinery to promote their own replication and evade immune responses. The Human Genome Project has provided new opportunities for developing better tools for the diagnosis and identification of target genes. Several epigenetic modifications, such as DNA methylation, histone modifications, and non-coding RNA expression, have been shown to influence infectious disease outcomes. Understanding the epigenetic mechanisms underlying infectious diseases may result in the progression of new therapeutic approaches focusing on host-pathogen interactions. The goal of this study is to show how different infectious agents interact with host cells after infection.

Keywords: epigenetic, infectious disease, micro-pathogenic organism, phenotype

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Authors: Alexis D'Agostino, Amanda Pomeroy

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Background: Resource availability is essential to effective implementation of national nutrition policies. To this end, the SPRING Project has collected and analyzed budget data from government ministries in Uganda, international donors, and other nutrition implementers to provide data for the first time on what funding is actually allocated to implement nutrition activities named in the national nutrition plan. Methodology: USAID’s SPRING Project used the Uganda Nutrition Action Plan (UNAP) as the starting point for budget analysis. Thorough desk reviews of public budgets from government, donors, and NGOs were mapped to activities named in the UNAP and validated by key informants (KIs) across the stakeholder groups. By relying on nationally-recognized and locally-created documents, SPRING provided a familiar basis for discussions to increase credibility and local ownership of findings. Among other things, the KIs validated the amount, source, and type (specific or sensitive) of funding. When only high-level budget data were available, KIs provided rough estimates of the percentage of allocations that were actually nutrition-relevant, allowing creation of confidence intervals around some funding estimates. Results: After validating data and narrowing in on estimates of funding to nutrition-relevant programming, researchers applied a formula to estimate overall nutrition allocations. In line with guidance by the SUN Movement and its three-step process, nutrition-specific funding was counted at 100% of its allocation amount, while nutrition sensitive funding was counted at 25%. The vast majority of nutrition funding in Uganda is off-budget, with over 90 percent of all nutrition funding is provided outside of the government system. Overall allocations are split nearly evenly between nutrition-specific and –sensitive activities. In FY 2013/14, the two-year study’s baseline year, on- and off-budget funding for nutrition was estimated to be around 60 million USD. While the 60 million USD allocations compare favorably to the 66 million USD estimate of the cost of the UNAP, not all activities are sufficiently funded. Those activities with a focus on behavior change were the most underfunded. In addition, accompanying qualitative research suggested that donor funding for nutrition activities may shift government funding into other areas of work, making it difficult to estimate the sustainability of current nutrition investments.Conclusions: Beyond providing figures, these estimates can be used together with the qualitative results of the study to explain how and why these amounts were allocated for particular activities and not others, examine the negotiation process that occurred, and suggest options for improving the flow of finances to UNAP activities for the remainder of the policy tenure. By the end of the PBN study, several years of nutrition budget estimates will be available to compare changes in funding over time. Halfway through SPRING’s work, there is evidence that country stakeholders have begun to feel ownership over the ultimate findings and some ministries are requesting increased technical assistance in nutrition budgeting. Ultimately, these data can be used within organization to advocate for more and improved nutrition funding and to improve targeting of nutrition allocations.

Keywords: budget, nutrition, financing, scale-up

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Authors: Yasaman Mohammadi

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Emotion regulation is a complex process that allows individuals to manage and modulate their emotional responses in order to adaptively respond to environmental demands. As individuals age, emotion regulation abilities may decline, leading to an increased vulnerability to mood disorders and other negative health outcomes. Advances in neuroimaging techniques have greatly enhanced our understanding of the neural substrates underlying emotion regulation and age-related changes in these neural systems. Additionally, genetic research has identified several candidate genes that may influence age-related changes in emotion regulation. In this paper, we review recent findings from neuroimaging and genetic research on age-related changes in the neural substrates of emotion regulation, highlighting the mechanisms and consequences of these changes. We also discuss potential interventions, including cognitive and behavioral approaches, that may be effective in mitigating age-related declines in emotion regulation. We propose that a better understanding of the mechanisms underlying age-related changes in emotion regulation may lead to the development of more targeted interventions aimed at promoting healthy emotional functioning in older adults. Overall, this paper highlights the importance of studying age-related changes in emotion regulation and provides a roadmap for future research in this field.

Keywords: emotion regulation, aging, neural substrates, neuroimaging, emotional functioning, healthy aging

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Authors: Juan C. Martínez-Alfaro, Aracely Zúñiga, Fernando Ruíz-Zarate

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In recent years, the Katahdin sheep breeds have been one of the breeds with greater acceptance by sheep farmers in southwestern Mexico. The Hair Sheep breeds from tropical latitudes (16° to 21° North Latitude) show low estrus activity from January to May. By contrast, these breeds of sheep exhibit high estrus activity from August to December. However, the reproductive management of Hair Sheep crossbred is very limited, independently of the socioeconomic levels of sheep farmers. Thus, in crossbred of Hair Sheep, occurrence of lambing is greater in autumn (84%) than spring (16%). In this sense, the aim of this study was to determine the lambing in Crossbred of Katahdin sheep during different seasons of the year. The Hypothesis was that in crossbred of Katahdin sheep, the lambing period has a behavior seasonal in the Southwestern Mexico. The study design consisted in evaluating the lambing proportion in one herds of Katahdin ewes crossbred during one year (October 1st, 2015 to October 1st, 2016). The study was realized in a farm located in the municipality of Jiquipilas, in the State of Chiapas, Mexico (16° North Latitude). A total of 40 female sheep homogeneous in terms of physical condition, age and physiological state were selected; and they were fed in grazing continuous, mainly with Africa star grass (Cynodon lemfuensis) and they are provided with water and mineral salts ad libitum; during the dry season, the ewes were supplemented with a diet of maize and sorghum, and the reproductive management was continuous mating. The lambing proportion was analyzed by chi-squared test, using SAS statistical software. The proportion of Katahdin ewes crossbred that lambed during the study period was high (100%; 40/40), the prolificacy was 1.42 (lamb/lambing). The proportion of lambing was higher (P<0.05) in autumn (67.5%; 27/40), than winter, spring and summer (32.5%; 13/40; 0%; 0/40; 0%; 0/40; respectively). The proportion of lambing was greater (P<0.05) in November (50%; 20/40), compared to October, December and January (2.5%; 1/40; 27.5%; 11/40; 20%; 8/40, respectively). The results are consistent with the fact that in the Hair Sheep Breeds, the lambing appears behave seasonally. The most important finding is that the lambing period in the crossbred of Katahdin Sheep is similar to the crossbred of Hair Sheep in tropical regions of Mexico. Therefore, the period of greater sexual activity occurs in the spring season. In conclusion, the period of lambing in crossbred of Katahdin ewes appears behave seasonally. Further researches to assess the ovarian activity in different breeds of Hair Ewes are under assessment.

Keywords: Katahdin ewes, lambing, prolificacy, seasonality

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Authors: Lei Xue, Liye Zhao, Jundong Wang, Yu Xue

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A hybrid energy conversion system composed of a floating offshore wind turbine (FOWT) and wave energy converters (WECs) may possibly reduce the levelized cost of energy, improving the platform dynamics and increasing the capacity to harvest energy. This paper investigates the aerodynamic performance and dynamic responses of the combined semi-submersible FOWT and point-absorber WECs in frequency and time domains using synthetic optimizing control under turbulent wind and irregular wave conditions. Individual pitch control is applied to the FOWT part, while spring–damping control is used on the WECs part, as well as the synergistic control effect of both are studied. The effect of the above control optimization is analyzed under several typical working conditions, such as below-rated wind speed, rated wind speed, and above-rated wind speed by OpenFAST and WEC-Sim software. Particularly, the wind-wave misalignment is also comparatively investigated, which has demonstrated the importance of applying proper integrated optimal control in this hybrid energy system. More specifically, the combination of individual pitch control and spring–damping control is able to mitigate the platform pitch motion and improve output power. However, the increase in blade root load needs to be considered which needs further investigations in the future.

Keywords: floating offshore wind turbine, wave energy converters, control optimization, individual pitch control, dynamic response

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Authors: Orly Yona Drori, Shirley Ben Shlomo

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Objectives: The participants will be able to recognize the predictors of binge eating addiction among women who suffer from psychological abuse in their relationships and will recognize the role of woman's defense mechanisms in moderating the association between psychological abuse and binge eating addiction. Methods: A convenience sample of 380 Israeli women in relationships were located via the Internet, and after consenting to participate in the study, they completed a series of structured questionnaires (The Yale Food Addiction Scale; The Defense Style Questionnaire; psychological maltreatment of women by their male partners; level of differentiation of self; sociodemographic questionnaire). Results: The higher the level of differentiation and mature defense mechanisms, the less addictive a woman is. However, the level of addiction among women who experience psychological abuse within their intimate relations is higher than women who do not experience psychological abuse in their relationship. Among women who experienced psychological abuse in their relations, the defense mechanisms moderate the association between psychological abuse within intimate relations and the extent of the addiction to binge eating. Conclusions: The study contributes to the therapy of women with binge eating addictions, as it raises awareness of therapeutic-related content that could strengthen women and help them to cope with situations in their lives without the need to binge. One of the significant variables for therapeutic work is the level of differentiation of the self. In addition, identifying the types of defense mechanisms might help to match treatment to the woman's emotional needs. The current study found also that it is important to identify the environmental systems by which the addict is surrounded, such as whether woman is in an abusive relationship. Finally the study leads to the recognition that binge eating, which is usually treated with an emphasis on nutritional behavior change, is an addiction, and as such, it requires a combination of mental, nutritional and behavioral therapy. In view of this approach, it is recommended that treating a woman who is addicted to binge eating should involve a multi-disciplinary team comprised of physicians, clinical dietitians, and clinical psychotherapists.

Keywords: binge eating, defence mechanism, food addiction, psychological abuse

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Authors: Aylin Mohammadalipour Tofighi

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Marine-based geoengineering methods, proposed to mitigate climate change, operate primarily through two mechanisms: reducing atmospheric carbon dioxide levels and diminishing solar absorption by the oceans. While these approaches promise beneficial outcomes, they are fraught with environmental, legal, ethical, and political challenges, necessitating robust international governance. This paper underscores the critical role of international cooperation within the governance framework, offering a focused analysis of existing international environmental mechanisms applicable to marine-based geoengineering governance. It evaluates the efficacy and limitations of current international legal structures, including treaties and organizations, in managing marine-based geoengineering, noting significant gaps such as the absence of specific regulations, dedicated international entities, and explicit governance mechanisms such as monitoring. To rectify these problems, the paper advocates for concrete steps to bolster international cooperation. These include the formulation of dedicated marine-based geoengineering guidelines within international agreements, the establishment of specialized supervisory entities, and the promotion of transparent, global consensus-building. These recommendations aim to foster governance that is environmentally sustainable, ethically sound, and politically feasible, thereby enhancing knowledge exchange, spurring innovation, and advancing the development of marine-based geoengineering approaches. This study emphasizes the importance of collaborative approaches in managing the complexities of marine-based geoengineering, contributing significantly to the discourse on international environmental governance in the face of rapid climate and technological changes.

Keywords: climate change, environmental law, international cooperation, international governance, international law, marine-based geoengineering, marine law, regulatory frameworks

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Authors: Mads Schultz, Galice Hoarau, Marvin Choquet

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Members of the genus Calanus are key species in the North Atlantic and Arctic marine ecosystems due to their vast abundance and their ability to accumulate high amounts of lipid. As a link between primary producers and higher trophic levels, the temporal presence of each Calanus species is important in a time of changing communities and northward distribution shifts. This study focused on the temporal niches of the sympatric species Calanus helgolandicus, Calanus finmarchicus, Calanus glacialis, and Calanus hyperboreus in Skjerstad fjord, a Norwegian fjord (67˚14’N, 14 ˚44’E). Three depth intervals were sampled monthly over a year, targeting copepodite stages of the genus Calanus. Species determination was carried out genetically using insertion/deletion markers. In addition, during the reproductive season (Jan-May), weekly samples of the upper 50 meters of the water column targeting nauplii and 5 depth intervals targeting copepodites were collected. Nauplii samples were sorted into two groups (NI-NIII and NIV-NVI), and species were genetically identified. Specimens from stage CIV to adults from each depth interval of copepodite sampling were photographed in order to generate a supporting timeline of visual traits, including gonad maturation stage, presence of stomach content, and total lipid content. The most abundant species were Calanus finmarchicus and Calanus glacialis, followed by Calanus hyperboreus. These species were present in the water column throughout the year, whereas Calanus helgolandicus, the least abundant species, was only present during the summer and autumn period. Each species showed distinct temporal niches, with Calanus finmarchicus occupying the upper 50 meters longer than any of the other species. Calanus hyperboreus dominates in abundance early in the spring but are outnumbered by Calanus glacialis and Calanus finmarchicus after spring bloom sets in. In Skjerstad fjord, Calanus hyperboreus is a clear capital breeder with a long period of nauplii presence before the spring bloom. Calanus glacialis and Calanus finmarchicus both utilize income breeding, with Calanus glacialis developing to the larger nauplii stages quicker than Calanus finmarchicus, but also having a shorter reproduction period. Indeed, the “traditional Arctic” species Calanus hyperboreus and Calanus glacialis appear to end their reproduction period earlier than the North Atlantic Calanus finmarchicus.

Keywords: calanus, depth distribution, reproduction, stage composition, temporal niches

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Authors: Youru Zhou

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This paper seeks to unveil the quality assurance practices in the Chinese translation industry. Since China’s reform and opening up, the Chinese language service industry has enjoyed impressively rapid growth. However, while still in its early stage of professionalization, the Chinese translation industry is also facing many challenges, such as the lack of clear admission requirements, a powerful regulation authority and a great number of qualified professionals. ‘How quality is assured’ means a great deal to translation in China at this stage. In order to examine the mechanisms in which quality is assured, this paper studied four international and national standards that have gained widespread adoption by Chinese translation companies and examined the content that is relevant to translation quality assurance. Case studies with six selected Chinese translation companies of different sizes were conducted to confirm and exemplify the descriptions on the standards. It has been found that quality in the industry is a relative concept which is mainly determined by the demand of clients. Furthermore, the procedures of translation can vary from task to task dependent on the agreement made between the service provider and clients. Finally, there are companies relying on expert-oriented mechanisms to assure the quality of translation, while other companies and standards insist on process-oriented ones.

Keywords: case study, Chinese translation industry, professional practice, translation quality assurance, translation standards

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Authors: Johns Paul, Santhosh J. Nalluveettil, P. Purushothaman, M. Premdas

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Lunar landing is one of the most critical phases of lunar mission. The lander is provided with a soft landing system to prevent structural damage of lunar module by absorbing the landing shock and also assure stability during landing. Presently available software are not capable to simulate the rigid body dynamics coupled with contact simulation and elastic/plastic deformation analysis. Hence a separate mathematical model has been generated for studying the dynamics of a typical lunar soft lander. Parameters used in the analysis includes lunar surface slope, coefficient of friction, initial touchdown velocity (vertical and horizontal), mass and moment of inertia of lander, crushing force due to energy absorbing material in the legs, number of legs and geometry of lander. The mathematical model is capable to simulate plastic and elastic deformation of honey comb, frictional force between landing leg and lunar soil, surface contact simulation, lunar gravitational force, rigid body dynamics and linkage dynamics of inverted tripod landing gear. The non linear differential equations generated for studying the dynamics of lunar lander is solved by numerical method. Matlab programme has been used as a computer tool for solving the numerical equations. The position of each kinematic joint is defined by mathematical equations for the generation of equation of motion. All hinged locations are defined by position vectors with respect to body fixed coordinate. The vehicle rigid body rotations and motions about body coordinate are only due to the external forces and moments arise from footpad reaction force due to impact, footpad frictional force and weight of vehicle. All these force are mathematically simulated for the generation of equation of motion. The validation of mathematical model is done by two different phases. First phase is the validation of plastic deformation of crushable elements by employing conservation of energy principle. The second phase is the validation of rigid body dynamics of model by simulating a lander model in ADAMS software after replacing the crushable elements to elastic spring element. Simulation of plastic deformation along with rigid body dynamics and contact force cannot be modeled in ADAMS. Hence plastic element of primary strut is replaced with a spring element and analysis is carried out in ADAMS software. The same analysis is also carried out using the mathematical model where the simulation of honeycomb crushing is replaced by elastic spring deformation and compared the results with ADAMS analysis. The rotational motion of linkages and 6 degree of freedom motion of lunar Lander about its CG can be validated by ADAMS software by replacing crushing element to spring element. The model is also validated by the drop test results of 4 leg lunar lander. This paper presents the details of mathematical model generated and its validation.

Keywords: honeycomb, landing leg tripod, lunar lander, primary link, secondary link

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Authors: Amandeep Singh Dhaliwal

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Networking solutions, particularly wireless local area networks have revolutionized the technological advancement. Wireless Local Area Networks (WLANs) have gained a lot of popularity as they provide location-independent network access between computing devices. There are a number of access methods used in Wireless Networks among which DCF and PCF are the fundamental access methods. This paper emphasizes on the impact of DCF and PCF access mechanisms on the performance of the IEEE 802.11a, 802.11b and 802.11g standards. On the basis of various parameters viz. throughput, delay, load etc performance is evaluated between these three standards using above mentioned access mechanisms. Analysis revealed a superior throughput performance with low delays for 802.11g standard as compared to 802.11 a/b standard using both DCF and PCF access methods.

Keywords: DCF, IEEE, PCF, WLAN

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Authors: Aiza G. Clanor, Lotlot B. Hernandez, Jonna Marie T. Ibuna

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This study aimed to know the coping mechanisms of Batangueño families facing cancer, specifically, those from Cancer Warriors Foundation, Inc. Batangas chapter. The researchers used purposive sampling. This study was limited to the responses provided by the Batangueño families of the cancer patients. A family member of the immediate family with a child facing cancer represents the family as a whole. A total number of forty six (46) respondents were given the questionnaires. Upon analysis, most of the respondents came from rural areas and nuclear family and have Php 5000 and below family monthly income. Most of them have their own houses, and 3 to 5 members, one of whom is a cancer patient diagnosed for more than 2 years. The two most frequently utilized coping strategies were mobilizing the family to acquire and accept help, and reframing. Passive appraisal is the least utilized one. There was a significant difference on the coping mechanisms of the family relative to passive appraisal based on the length of time since the illness was first diagnosed. Based from the study, the researchers developed modules with discussions and activities on cancer awareness, ideas on coping and how to deal with the cancer patients that may help the respondents and other Batangueño families overcome the difficulties in facing cancer. The researchers recommend the modules for they are found to be effective ways to help the families relieve stress, reduce anxiety and improve quality of life.

Keywords: coping with chronic illness, family, psychology, cancer

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Authors: Sukran Acikel, Mehmet Ekmekci, Otgonbayar Namkhai

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Lignite coal fields in western Turkey generally occurs in tensional Neogene basins bordered by major faults. Karacahisar coal field in Mugla province of western Turkey is a large Neogene basin filled with alternation of silisic and calcerous layers. The basement of the basin is composed of mainly karstified carbonate rocks of Mesozoic and schists of Paleozoic age. The basement rocks are exposed at highlands surrounding the basin. The basin fill deposits forms shallow, low yield and local aquifers whereas karstic carbonate rock masses forms the major aquifer in the region. The karstic aquifer discharges through a spring zone issuing at intersection of two major faults. Municipal water demand in Bodrum city, a touristic attraction area is almost totally supplied by boreholes tapping the karstic aquifer. A well field has been constructed on the eastern edge of the coal basin, which forms a ridge separating two Neogene basins. A major concern was raised about the plausible impact of mining activities on groundwater system in general and on water supply well field in particular. The hydrogeological studies carried out in the area revealed that the coal seam is located below the groundwater level. Mining operations will be affected by groundwater inflow to the pits, which will require dewatering measures. Dewatering activities in mine sites have two-sided effects: a) lowers the groundwater level at and around the pit for a safe and effective mining operation, b) continuous dewatering causes expansion of cone of depression to reach a spring, stream and/or well being utilized by local people, capturing their water. Plausible effect of mining operations on the flow of the spring zone was another issue of concern. Therefore, a detailed representative hydrogeological conceptual model of the site was developed on the basis of available data and field work. According to the hydrogeological conceptual model, dewatering of Neogene layers will not hydraulically affect the water supply wells, however, the ultimate perimeter of the open pit will expand to intersect the well field. According to the conceptual model, the coal seam is separated from the bottom by a thick impervious clay layer sitting on the carbonate basement. Therefore, the hydrostratigraphy does not allow a hydraulic interaction between the mine pit and the karstic carbonate rock aquifer. However, the structural setting in the basin suggests that deep faults intersecting the basement and the Neogene sequence will most probably carry the deep groundwater up to a level above the bottom of the pit. This will require taking necessary measure to lower the piezometric level of the carbonate rock aquifer along the faults. Dewatering the carbonate rock aquifer will reduce the flow to the spring zone. All findings were put together to recommend a strategy for safe and effective mining operation.

Keywords: conceptual model, dewatering, groundwater, mining operation

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Authors: Gwyneth Bernier

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An authoritative literature review of peer-reviewed journals and edited books on East African refugees' coping strategies identifies the four most common coping skills among this group as the following: (1) relying on faith, religion, or another belief system, (2) turning to communities or social supports, (3) cognitive reframing--in other words, finding meaning in one's traumas or hardships--and (4) finding hope for the future, especially through education. However, this review recognizes that there are gaps in knowledge in this field and that the validity of these general findings must be further investigated in East African refugees who are women, have not been resettled in Western countries, and belong to specific nationality groups. This review also suggests studies that build on the current body of research begin to use qualitative methods of data collection and analysis. This paper aims to bridge part of that gap in understanding using a qualitative methodology. Specifically, it provides a more holistic view of East African refugees' psychological coping mechanisms through its analysis of trends observed across life story interviews from two participant groups: Sudanese refugee women in Cairo's informal settlements, Egypt and Congolese refugee women in Rwanda's Mahama camp.

Keywords: Congolese refugees, coping mechanisms, refugee women, Sudanese refugees

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Authors: Iris Lavalle Acejo, Helen Sampson

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Drawing from the perspectives of female seafarers, this article offers an analysis of an empirical investigation of the mechanisms by which women are excluded from working on board cargo ships. Female seafarers currently make up about 1% of seafarers in the global cargo shipping industry. As female presence onboard continues to constitute a small proportion of the total crew, we consider their professional advancement in comparison with their male counterparts and the ways in which they are discouraged from entering, or remining within, the industry. With interactions at work severely constrained by the traditionally masculine working culture of the ship, the study hopes to provide insights on the mechanisms in which they face and navigate barriers as they both accommodate and resist gendered differences onboard.

Keywords: female seafarers, glasswalls, genderbarriers, genderedworkplaces

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Authors: G. Edwards, N. Dybro, L. J. Munkholm, C. G. Sørensen

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Planning agricultural operations requires an understanding of when fields are ready for operations. However determining a field’s readiness is a difficult process that can involve large amounts of data and an experienced farm manager. A consequence of this is that operations are often executed when fields are unready, or partially unready, which can compromise results incurring environmental impacts, decreased yield and increased operational costs. In order to assess timeliness of operations’ execution, a new scheme is introduced to quantify the aptitude of farm managers to plan operations. Two criteria are presented by which the execution of operations can be evaluated as to their exploitation of a field’s readiness window. A dataset containing the execution dates of spring and autumn operations on 93 fields in Iowa, USA, over two years, was considered as an example and used to demonstrate how operations’ executions can be evaluated. The execution dates were compared with simulated data to gain a measure of how disparate the actual execution was from the ideal execution. The presented tool is able to evaluate the spring operations better than the autumn operations as required data was lacking to correctly parameterise the crop model. Further work is needed on the underlying models of the decision support tool in order for its situational knowledge to emulate reality more consistently. However the assessment methods and evaluation criteria presented offer a standard by which operations' execution proficiency can be quantified and could be used to identify farm managers who require decisional support when planning operations, or as a means of incentivising and promoting the use of sustainable farming practices.

Keywords: operation management, field readiness, sustainable farming, workability

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Authors: G. Khamooshian

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One of the main points of application of the mechanisms of the series and parallel is the subject of managing them. The control of this mechanism and similar mechanisms is one that has always been the intention of the scholars. On the other hand, modeling the behavior of the system is difficult due to the large number of its parameters, and it leads to complex equations that are difficult to solve and eventually difficult to control. In this paper, a six-linkage robot has been presented that could be used in different areas such as medical robots. Using these robots needs a robust control. In this paper, the system equations are first found, and then the system conversion function is written. A new controller has been designed for this robot which could be used in other parallel robots and could be very useful. Parallel robots are so important in robotics because of their stability, so methods for control of them are important and the robust controller, especially in parallel robots, makes a sense.

Keywords: 3-RRS, 6 linkage, parallel robot, control

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Authors: H. Lee, J. Park

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In this present study, for the first time, we retrieved the Formaldehyde (HCHO) Vertical Column Density (HCHOVCD) using Pandora instruments in Seoul, a megacity in northeast Asia, for the period between 2012 and 2014 and investigated the temporal characteristics of HCHOVCD. HCHO Slant Column Density (HCHOSCD) was obtained using the Differential Optical Absorption Spectroscopy (DOAS) method. HCHOSCD was converted to HCHOVCD using geometric Air Mass Factor (AMFG) as Pandora is the direct-sun measurement. The HCHOVCDs is low at 12:00 Local Time (LT) and is high in the morning (10:00 LT) and late afternoon (16:00 LT) except for winter. The maximum (minimum) values of Pandora HCHOVCD are 2.68×1016 (1.63×10¹⁶), 3.19×10¹⁶ (2.23×10¹⁶), 2.00×10¹⁶ (1.26×10¹⁶), and 1.63×10¹⁶ (0.82×10¹⁶) molecules cm⁻² in spring, summer, autumn, and winter, respectively. In terms of seasonal variations, HCHOVCD was high in summer and low in winter which implies that photo-oxidation plays an important role in HCHO production in Seoul. In comparison with the Ozone Monitoring Instrument (OMI) measurements, the HCHOVCDs from the OMI are lower than those from Pandora. The correlation coefficient (R) between monthly HCHOVCDs values from Pandora and OMI is 0.61, with slop of 0.35. Furthermore, to understand HCHO mixing ratio within Planetary Boundary Layer (PBL) in Seoul, we converted Pandora HCHOVCDs to HCHO mixing ratio in the PBL using several meteorological input data from the Atmospheric InfraRed Sounder (AIRS). Seasonal HCHO mixing ratio in PBL converted from Pandora (OMI) HCHOVCDs are estimated to be 6.57 (5.17), 7.08 (6.68), 7.60 (4.70), and 5.00 (4.76) ppbv in spring, summer, autumn, and winter, respectively.

Keywords: formaldehyde, OMI, Pandora, remote sensing

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Authors: Mykola G. Boichuk

Abstract:

The paper concerns predatory pricing incentives and mechanisms in the markets of services, as well as its anti-competitive effects. As cost estimation at services markets is more complex in comparison to markets of goods, predatory pricing is more difficult to detect in the provision of services. For instance, this is often the case for professional services, which is analyzed in the paper. The special attention is given to employment markets as de-facto main supply markets for professional services markets. Also, the paper concerns such instances as travel agents' services, where predatory pricing may have implications not only on competition but on a wider range of public interest as well. Thus, the paper develops on effective ways to apply competition law rules on predatory pricing to the provision of services.

Keywords: employment markets, predatory pricing, services markets, unfair competition

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Authors: Farbod Rohani, Elyar Ghafoori, Matin Saeedkondori

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Impulse noise is electromagnetic emission which generated by many house hold appliances that are attached to the electrical network. The main difficulty of impulsive noise (IN) elimination process from communication channels is to distinguish it from the transmitted signal and more importantly choosing the proper threshold bandwidth in order to eliminate the signal. Because of wide band property of impulsive noise, we present a novel method for setting the detection threshold, by taking advantage of the fact that impulsive noise bandwidth is usually wider than that of typical communication channels and specifically OFDM channel. After IN detection procedure, we apply simple windowing mechanisms to eliminate them from the communication channel.

Keywords: impulsive noise, OFDM channel, threshold detecting, windowing mechanisms

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Authors: Cheba Ben Amar

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Bacillus and Paenibacillus are Gram-positive aerobic endospore-forming bacteria (AEFB) and most abundant in the rhizosphere, they mediated plant growth promotion and disease protection by several complex and interrelated processes involving direct and indirect mechanisms that include nitrogen fixation, phosphate solubilization, siderophores production, phytohormones production and plant diseases control. In addition to their multiple PGPR properties, high secretory capacity, spore forming ability and spore resistance to unfavorable conditions enabling their extended commercial applications for long shelf-life. Due to these unique advantages, Bacillus species were the most an ideal candidate for developing efficient PGPR products such as biopesticides, fungicides and fertilizers. This review list all studied and reported plant growth promoting Bacillus species and strains, discuss their capacities to enhance plant growth and protection with special focusing on the most frequent species Bacillus subtilis, B. pumilus ,B. megaterium, B. amyloliquefaciens , B. licheniformis and B. sphaericus, furthermore we recapitulate the beneficial activities and mechanisms of several species and strains of the genus Paenibacillus involved in plant growth stimulation and plant disease control.

Keywords: bacillus, paenibacillus, PGPR, beneficial activities, mechanisms, growth promotion, disease control, agrobiotechnology

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Authors: M. Kharrat, G. Moreau, Z. Aboura

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The latest advances in the weaving industry, combined with increasingly sophisticated means of materials processing, have made it possible to produce complex 3D composite structures. Mainly used in aeronautics, composite materials with 3D architecture offer better mechanical properties than 2D reinforced composites. Nevertheless, these materials require a good understanding of their behavior. Because of the complexity of such materials, the damage mechanisms are multiple, and the scenario of their appearance and evolution depends on the nature of the exerted solicitations. The AE technique is a well-established tool for discriminating between the damage mechanisms. Suitable sensors are used during the mechanical test to monitor the structural health of the material. Relevant AE-features are then extracted from the recorded signals, followed by a data analysis using pattern recognition techniques. In order to better understand the damage scenarios of interlock composite materials, a multi-instrumentation was set-up in this work for tracking damage initiation and development, especially in the vicinity of the first significant damage, called macro-damage. The deployed instrumentation includes video-microscopy, Digital Image Correlation, Acoustic Emission (AE) and micro-tomography. In this study, a multi-variable AE data analysis approach was developed for the discrimination between the different signal classes representing the different emission sources during testing. An unsupervised classification technique was adopted to perform AE data clustering without a priori knowledge. The multi-instrumentation and the clustered data served to label the different signal families and to build a learning database. This latter is useful to construct a supervised classifier that can be used for automatic recognition of the AE signals. Several materials with different ingredients were tested under various solicitations in order to feed and enrich the learning database. The methodology presented in this work was useful to refine the damage threshold for the new generation materials. The damage mechanisms around this threshold were highlighted. The obtained signal classes were assigned to the different mechanisms. The isolation of a 'noise' class makes it possible to discriminate between the signals emitted by damages without resorting to spatial filtering or increasing the AE detection threshold. The approach was validated on different material configurations. For the same material and the same type of solicitation, the identified classes are reproducible and little disturbed. The supervised classifier constructed based on the learning database was able to predict the labels of the classified signals.

Keywords: acoustic emission, classifier, damage mechanisms, first damage threshold, interlock composite materials, pattern recognition

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Authors: Grace E. Santella, Shawn G. Gallaher, Joseph P. Smith

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In order to determine the importance of small-system riverine heat flux on regional landfast sea ice breakup, our study explores the annual spring freshet of the Sagavanirktok River from 2014-2019. Seasonal heat cycling ultimately serves as the driving mechanism behind the freshet; however, as an emerging area of study, the extent to which inland thermodynamics influence coastal tundra geomorphology and connected landfast sea ice has not been extensively investigated in relation to small-scale Arctic river systems. The Sagavanirktok River is a small-to-midsized river system that flows south-to-north on the Alaskan North Slope from the Brooks mountain range to the Beaufort Sea at Prudhoe Bay. Seasonal warming in the spring rapidly melts snow and ice in a northwards progression from the Brooks Range and transitional tundra highlands towards the coast and when coupled with seasonal precipitation, results in a pulsed freshet that propagates through the Sagavanirktok River. The concentrated presence of newly exposed vegetation in the transitional tundra region due to spring melting results in higher absorption of solar radiation due to a lower albedo relative to snow-covered tundra and/or landfast sea ice. This results in spring flood runoff that advances over impermeable early-season permafrost soils with elevated temperatures relative to landfast sea ice and sub-ice flow. We examine the extent to which interannual temporal variability influences the onset and magnitude of river discharge by analyzing field measurements from the United States Geological Survey (USGS) river and meteorological observation sites. Rapid influx of heat to the Arctic Ocean via riverine systems results in a noticeable decay of landfast sea ice independent of ice breakup seaward of the shear zone. Utilizing MODIS imagery from NASA’s Terra satellite, interannual variability of river discharge is visualized, allowing for optical validation that the discharge flow is interacting with landfast sea ice. Thermal erosion experienced by sediment fast ice at the arrival of warm overflow preconditions the ice regime for rapid thawing. We investigate the extent to which interannual heat flux from the Sagavanirktok River’s freshet significantly influences the onset of local landfast sea ice breakup. The early-season warming of atmospheric temperatures is evidenced by the presence of storms which introduce liquid, rather than frozen, precipitation into the system. The resultant decreased albedo of the transitional tundra supports the positive relationship between early-season precipitation events, inland thermodynamic cycling, and degradation of landfast sea ice. Early removal of landfast sea ice increases coastal erosion in these regions and has implications for coastline geomorphology which stress industrial, ecological, and humanitarian infrastructure.

Keywords: Albedo, freshet, landfast sea ice, riverine heat flux, seasonal heat cycling

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Authors: Saeed Mohammadirad

Abstract:

During the first commitment period of the Kyoto Protocol, many developed countries were forced to restrict carbon emissions. Although Iran was one of the countries of Kyoto protocol, due to some special conditions, it was not required to restrict its carbon emissions. Flexible mechanisms were developed to assist countries responsible for reducing their carbon emissions, and regulated carbon markets were introduced. Carbon credits which are provided by organizations in countries with no responsibility to restrict their carbon emissions are traded in voluntary markets. This study focuses on how to measure and report the carbon allowances and carbon credits from accounting view point under both regulated and voluntary markets.

Keywords: carbon credits, carbon markets, accounting, flexible mechanisms

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Authors: Gayane Vardanyan, Gaia Narciso, Battista Severgnini

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This paper investigates the long-run impact of the Great Irish Famine on emigration from Ireland at the turn of the twentieth century. To do it we combine the 1901 and the 1911 Irish Census data sets with the Ellis Island Administrative Records on Irish migrants to the United States. We find that the migrants were more likely to be Catholic, literate, unmarried, young and Gaelic speaking compared to the ones that stay. Running individual level specifications, our preliminary findings suggest that being born in a place where the Famine was more severe increases the probability of becoming a migrant in the long-run. We also intend to explore the mechanisms through which this impact occurs.

Keywords: Great Famine, mass migration, long-run impact, mechanisms

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