Search results for: seasonal unit root

Authors: Huseyin Guler, Cigdem Kosar

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The aim of this study is to propose Bridge estimator for seasonal unit root tests. Seasonality is an important factor for many economic time series. Some variables may contain seasonal patterns and forecasts that ignore important seasonal patterns have a high variance. Therefore, it is very important to eliminate seasonality for seasonal macroeconomic data. There are some methods to eliminate the impacts of seasonality in time series. One of them is filtering the data. However, this method leads to undesired consequences in unit root tests, especially if the data is generated by a stochastic seasonal process. Another method to eliminate seasonality is using seasonal dummy variables. Some seasonal patterns may result from stationary seasonal processes, which are modelled using seasonal dummies but if there is a varying and changing seasonal pattern over time, so the seasonal process is non-stationary, deterministic seasonal dummies are inadequate to capture the seasonal process. It is not suitable to use seasonal dummies for modeling such seasonally nonstationary series. Instead of that, it is necessary to take seasonal difference if there are seasonal unit roots in the series. Different alternative methods are proposed in the literature to test seasonal unit roots, such as Dickey, Hazsa, Fuller (DHF) and Hylleberg, Engle, Granger, Yoo (HEGY) tests. HEGY test can be also used to test the seasonal unit root in different frequencies (monthly, quarterly, and semiannual). Another issue in unit root tests is the lag selection. Lagged dependent variables are added to the model in seasonal unit root tests as in the unit root tests to overcome the autocorrelation problem. In this case, it is necessary to choose the lag length and determine any deterministic components (i.e., a constant and trend) first, and then use the proper model to test for seasonal unit roots. However, this two-step procedure might lead size distortions and lack of power in seasonal unit root tests. Recent studies show that Bridge estimators are good in selecting optimal lag length while differentiating nonstationary versus stationary models for nonseasonal data. The advantage of this estimator is the elimination of the two-step nature of conventional unit root tests and this leads a gain in size and power. In this paper, the Bridge estimator is proposed to test seasonal unit roots in a HEGY model. A Monte-Carlo experiment is done to determine the efficiency of this approach and compare the size and power of this method with HEGY test. Since Bridge estimator performs well in model selection, our approach may lead to some gain in terms of size and power over HEGY test.

Keywords: bridge estimators, HEGY test, model selection, seasonal unit root

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Authors: Wararit Panichkitkosolkul

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The unit root tests based on the robust estimator for the first-order autoregressive process are proposed and compared with the unit root tests based on the ordinary least squares (OLS) estimator. The percentiles of the null distributions of the unit root test are also reported. The empirical probabilities of Type I error and powers of the unit root tests are estimated via Monte Carlo simulation. Simulation results show that all unit root tests can control the probability of Type I error for all situations. The empirical power of the unit root tests based on the robust estimator are higher than the unit root tests based on the OLS estimator.

Keywords: autoregressive, ordinary least squares, type i error, power of the test, Monte Carlo simulation

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Authors: C. Slim

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Traditional techniques for analyzing time series are based on the notion of stationarity of phenomena under study, but in reality most economic and financial series do not verify this hypothesis, which implies the implementation of specific tools for the detection of such behavior. In this paper, we study nonstationary non-seasonal time series tests in a non-exhaustive manner. We formalize the problem of nonstationary processes with numerical simulations and take stock of their statistical characteristics. The theoretical aspects of some of the most common unit root tests will be discussed. We detail the specification of the tests, showing the advantages and disadvantages of each. The empirical study focuses on the application of these tests to the exchange rate (USD/TND) and the Consumer Price Index (CPI) in Tunisia, in order to compare the Power of these tests with the characteristics of the series.

Keywords: stationarity, unit root tests, economic time series, ADF tests

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Authors: Yajun Qiao, Yaner Yan, Ning Li, Shuqing An

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In order to relieve the pressure on a land resource from a huge population, reclamation has occurred in many coastal wetlands. Plants can maintain their elemental composition within normal limits despite the variations of external conditions. Reclamation may affect carbon (C), nitrogen (N) and phosphorus (P) stoichiometry in the plant to some extent by altering physical and chemical properties of soil in a coastal wetland. We reported the seasonal dynamic of C, N and P stoichiometry in root, stem and leaf of Suaeda salsa (L.) Pall. and in soil between reclamation plots and natural plots. Our results of three-way ANOVA indicated that sampling season always had significant effect on C, N, P concentrations and their ratios; organ had no significant effect on N, P concentration and N:P; plot type had no significant effect on N concentration and C:N. Sampling season explained the most variability of tissue N and P contents, C:N, C:P and N:P, while it’s organ for C using the restricted maximum likelihood (REML) method. By independent sample T-test, we found that reclamation affect more on C, N and P stoichiometry of stem than that of root or leaf on the whole. While there was no difference between reclamation plots and natural plots for soil in four seasons. For three organs, C concentration had peak values in autumn and minimum values in spring while N concentration had peak values in spring and minimum values in autumn. For P concentration, three organs all had peak values in spring; however, the root had minimum value in winter, the stem had that in autumn, and leaf had that in summer. The seasonal dynamic of C, N and P stoichiometry in a leaf of Suaeda salsa were much steadier than that in root or stem under the drive of reclamation.

Keywords: nitrogen, phosphorus, reclamation, seasonal dynamic, Suaeda salsa

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Authors: Ayuko Itsuki, Sachiyo Aburatani

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The seasonal (January, April, July and October) and monthly soil respiration rate and the monthly litter fall amounts were examined in the laurel-leaved (B_B-1) and Cryptomeria japonica (B_B-2 and PW) forests in the Kasugayama Hill Primeval Forest (Nara, Japan). The change of the seasonal soil respiration rate corresponded to that of the soil temperature. The soil respiration rate was higher in October when fresh organic matter was supplied in the forest floor than in April in spite of the same temperature. The seasonal soil respiration rate of B_B-1 was higher than that of B_B-2, which corresponded to more numbers of bacteria and fungi counted by the dilution plate method and by the direct count method by microscopy in B_B-1 than that of B_B-2. The seasonal soil respiration rate of B_B-2 was higher than that of PW, which corresponded to more microbial biomass by the direct count method by microscopy in B_B-2 than that of PW. The correlation coefficient with the seasonal soil respiration and the soil temperature was higher than that of the monthly soil respiration. The soil respiration carbon was more than the litter fall carbon. It was suggested that the soil respiration included in the carbon dioxide which was emitted by the plant root and soil animal, or that the litter fall supplied to the forest floor included in animal and plant litter.

Keywords: field soil respiration rate, forest soil, litter fall, mineralization rate

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Authors: Eyup Dogan

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The number of research articles analyzing the integration properties of energy variables has rapidly increased in the energy literature for about a decade. The stochastic behaviors of energy variables are worth knowing due to several reasons. For instance, national policies to conserve or promote energy consumption, which should be taken as shocks to energy consumption, will have transitory effects in energy consumption if energy consumption is found to be stationary in one country. Furthermore, it is also important to know the order of integration to employ an appropriate econometric model. Despite being an important subject for applied energy (economics) and having a huge volume of studies, several known limitations still exist with the existing literature. For example, many of the studies use aggregate energy consumption and national level data. In addition, a huge part of the literature is either multi-country studies or solely focusing on the U.S. This is the first study in the literature that considers a form of energy consumption by sectors at sub-national level. This research study aims at investigating unit root properties of electricity consumption for 12 regions of Turkey by four sectors in addition to total electricity consumption for the purpose of filling the mentioned limits in the literature. In this regard, we analyze stationarity properties of 60 cases . Because the use of multiple unit root tests make the results robust and consistent, we apply Dickey-Fuller unit root test based on Generalized Least Squares regression (DFGLS), Phillips-Perron unit root test (PP) and Zivot-Andrews unit root test with one endogenous structural break (ZA). The main finding of this study is that electricity consumption is trend stationary in 7 cases according to DFGLS and PP, whereas it is stationary process in 12 cases when we take into account the structural change by applying ZA. Thus, shocks to electricity consumption have transitory effects in those cases; namely, agriculture in region 1, region 4 and region 7, industrial in region 5, region 8, region 9, region 10 and region 11, business in region 4, region 7 and region 9, total electricity consumption in region 11. Regarding policy implications, policies to decrease or stimulate the use of electricity have a long-run impact on electricity consumption in 80% of cases in Turkey given that 48 cases are non-stationary process. On the other hand, the past behavior of electricity consumption can be used to predict the future behavior of that in 12 cases only.

Keywords: unit root, electricity consumption, sectoral data, subnational data

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Authors: Soojin Kim, Jiwon Yang, Sungzoon Cho

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As a seasonal product is only in demand for a short time, inventory management is critical to profits. Both markdowns and stockouts decrease the return on perishable products; therefore, researchers have been interested in the distribution of seasonal products with the aim of maximizing profits. In this study, we propose a data-driven seasonal product sales pattern analysis method for individual retail outlets based on observed sales data clustering; the proposed method helps in determining distribution strategies.

Keywords: clustering, distribution, sales pattern, seasonal product

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Authors: Amjad Naveed

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This study analysed the role of structural change in the process of labour productivity convergence at country and regional levels. Many forms of structural changes occurred within the European Union (EU) countries i.e. variation in sectoral employment share, changes in demand for products, variations in trade patterns and advancement in technology which may have an influence on the process of convergence. Earlier studies on convergence have neglected the role of structural changes which can have resulted in different conclusion on the nature of convergence. The contribution of this study is to examine the role of structural change in testing labour productivity convergence at various levels. For the empirical purpose, the data of 19 EU countries, 259 regions and 6 industries is used for the period of 1991-2009. The results indicate that convergence varies across regional and country levels for different industries when considered the role of structural change.

Keywords: labor produvitivty, convergence, structural change, panel unit root

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Authors: H. Akman, A. Topal

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This work was conducted in greenhouse conditions in order to investigate root biomass growth of two bread wheat, two durum wheat and two barley cultivars that were grown in irrigated and dry lands, respectively. This work was planned with four replications at a Completely Randomized Block Design in 2011-2012 growing season. In the study, root biomass growth was evaluated at stages of stem elongation, complete of anthesis and full grain maturity. Results showed that there were significant differences between cultivars grown at dry and irrigated lands in all growth stages in terms of root biomass (P < 0.01). According to research results, all of growth stages, dry typed-bread and durum wheats generally had higher root biomass than irrigated typed-cultivars, furthermore that dry typed-barley cultivar, had higher root biomass at GS 31 and GS 69, however lower at GS 92 than Larende. In all cultivars, root biomass increased between GS 31 and GS 69 so that dry typed-cultivars had more root biomass increase than irrigated typed-cultivars. Root biomass of bread wheat increased between GS 69 and GS 92, however root biomass of barley and durum wheat decreased.

Keywords: bread and durum wheat, barley, root biomass, different growth stage

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Authors: Kassahun Birhanu Tadesse, Megersa Olumana Dinka

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Reliable future river flow information is basic for planning and management of any river systems. For data scarce river system having only a river flow records like the Waterval River, a univariate time series models are appropriate for river flow forecasting. In this study, a univariate Seasonal Autoregressive Integrated Moving Average (SARIMA) model was applied for forecasting Waterval River flow using GRETL statistical software. Mean monthly river flows from 1960 to 2016 were used for modeling. Different unit root tests and Mann-Kendall trend analysis were performed to test the stationarity of the observed flow time series. The time series was differenced to remove the seasonality. Using the correlogram of seasonally differenced time series, different SARIMA models were identified, their parameters were estimated, and diagnostic check-up of model forecasts was performed using white noise and heteroscedasticity tests. Finally, based on minimum Akaike Information (AIc) and Hannan-Quinn (HQc) criteria, SARIMA (3, 0, 2) x (3, 1, 3)12 was selected as the best model for Waterval River flow forecasting. Therefore, this model can be used to generate future river information for water resources development and management in Waterval River system. SARIMA model can also be used for forecasting other similar univariate time series with seasonality characteristics.

Keywords: heteroscedasticity, stationarity test, trend analysis, validation, white noise

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Authors: Priyakant Vaghela, Jagdish Prajapati

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Bending stress at the root of the gear tooth is the very important criteria in gear design and it should be kept the minimum. Minimization of bending stress at the root of the gear tooth is a recent demand from industry. This paper presents an innovative approach to obtain minimum bending stress at the root of a tooth by optimizing tooth root profile and drive side pressure angle. Circular-filleted at the root of the tooth is widely used in the design. Circular fillet creates discontinuity at the root of the tooth. So, at root stress concentration occurs. In order to minimize stress concentration, an important criterion is a G2 continuity at the blending of the gear tooth. A Bezier curve is used with G2 continuity at the root of asymmetric spur gear tooth. The comparison has been done between normal and modified tooth using ANSYS simulation. Tooth root profile and drive side pressure angle are optimized to minimize bending stress at the root of the tooth of the asymmetric involute spur gear. Von Mises stress of optimized profile is analyzed and compared with normal profile symmetric gear. Von Mises stress is reducing by 31.27% by optimization of drive side pressure angle and root profile. Stress concentration of modified gear was significantly reduced.

Keywords: asymmetric spur gear tooth, G2 continuity, pressure angle, stress concentration at the root of tooth, tooth root stress

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Authors: Amira Kalifa, Faïek Errouissi

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The seasonal changes and the daily activity of Stomoxys calcitrans (Diptera: Muscidae) were examined, using Vavoua traps, in a dairy cattle farm in Zaouiet Sousse, the Sahel area of Tunisia during May 2014 to October 2014. Over this period, a total of 4366 hematophagous diptera were captured and Stomoxys calcitrans was the most commonly trapped species (96.52%). Analysis of the seasonal activity, showed that S.calcitrans is bivoltine, with two peaks: a significant peak is recorded in May-June, during the dry season, and a second peak at the end of October, which is quite weak. This seasonal pattern would depend on climatic factors, particularly the temperature of the manure and that of the air. The activity pattern of Stomoxys calcitrans was diurnal with seasonal variations. The daily rhythm shows a peak between 11:00 am to 15:00 pm in May and between 11:00 am to 17:00 pm in June. These vector flies are important pests of livestock in Tunisia, where they are known as a mechanical vector of several pathogens and have a considerable economic and health impact on livestock. A better knowledge of their ecology is a prerequisite for more efficient control measures.

Keywords: cattle farm, daily rhythm, Stomoxys calcitrans, seasonal activity

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Authors: Gu Pang, Bartosz Gebka

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We forecast the demand of total container throughput at the Indonesia’s largest seaport, Tanjung Priok Port. We propose four univariate forecasting models, including SARIMA, the additive Seasonal Holt-Winters, the multiplicative Seasonal Holt-Winters and the Vector Error Correction Model. Our aim is to provide insights into whether forecasting the total container throughput obtained by historical aggregated port throughput time series is superior to the forecasts of the total throughput obtained by summing up the best individual terminal forecasts. We test the monthly port/individual terminal container throughput time series between 2003 and 2013. The performance of forecasting models is evaluated based on Mean Absolute Error and Root Mean Squared Error. Our results show that the multiplicative Seasonal Holt-Winters model produces the most accurate forecasts of total container throughput, whereas SARIMA generates the worst in-sample model fit. The Vector Error Correction Model provides the best model fits and forecasts for individual terminals. Our results report that the total container throughput forecasts based on modelling the total throughput time series are consistently better than those obtained by combining those forecasts generated by terminal-specific models. The forecasts of total throughput until the end of 2018 provide an essential insight into the strategic decision-making on the expansion of port's capacity and construction of new container terminals at Tanjung Priok Port.

Keywords: SARIMA, Seasonal Holt-Winters, Vector Error Correction Model, container throughput

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Authors: Noushin Shokouhinejad, Hasan Razmi, Reza Fekrazad, Saeed Asgary, Ammar Neshati, Hadi Assadian, Sanam Kheirieh

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This study compared the push-out bond strength of mineral trioxide aggregate (MTA) and a new endodontic cement (NEC) as root-end filling materials in root-end cavities prepared by ultrasonic technique (US) or Er,Cr:YSGG laser (L). Eighty single-rooted extracted human teeth were endodontically treated, apicectomised and randomly divided into four following groups (n = 20): US/MTA, US/NEC, L/MTA and L/NEC. In US/MTA and US/NEC groups, rooted cavities were prepared with ultrasonic retrotip and filled with MTA and NEC, respectively. In L/MTA and L/NEC groups, root-end cavities were prepared using Er, Cr:YSGG laser and filled with MTA and NEC, respectively. Each root was cut apically to create a 2 mm-thick root slice for measurement of bond strength using a universal testing machine. Then, all slices were examined to determine the mode of bond failure. Data were analysed using two-way ANOVA. Root-end filling materials showed significantly higher bond strength in root-end cavities prepared using the ultrasonic technique (US/MTA and US/NEC) (P < 0.001). The bond strengths of MTA and NEC did not differ significantly. The failure modes were mainly adhesive for MTA, but cohesive for NEC. In conclusion, bond strengths of MTA and NEC to root-end cavities were comparable and higher in ultrasonically prepared cavities.

Keywords: bond strength, Er, Cr:YSGG laser, MTA, NEC, root-end cavity

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Authors: F. N. U. Abdullah, A. M. H. Ibrahim, Shuyu Liu

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Hybrid wheat root system is the major plant organ for water and nutrient acquisition. An initial wheat root study with Winrhizo scanner showed that entries with high root surface area but narrow root angle are associated with past drought tolerance in Texas, while those with wide angle can perform best under normal growing conditions. In a hybrid field experiment, commercial heterosis up to 8.3% in grain yield was obtained from diverse parents selected from male and female diverse groups. These hybrids showed promising yield at Greenville and McGregor, Texas, with grain yield up to 4412 Kg ha⁻¹ as compared to best performing commercial varieties ‘TAM-304’ (4075 Kg ha⁻¹) and ‘Gallagher’ (3981 Kg ha⁻¹). Among 130 hybrids produced, a subset of 50 better-performing hybrids and parents was subjected to one-month-old plant root studies scanned with Winrhizo. The results showed a significant positive correlation of grain yield with initial root angle and a negative correlation with root length.

Keywords: hybrids, root studies, heterosis, wheat breeding

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Authors: Mesut BALIBEY, Serpil TÜRKYILMAZ

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A popular topic in the econometrics and time series area is the cointegrating relationships among the components of a nonstationary time series. Engle and Granger’s least squares method and Johansen’s conditional maximum likelihood method are the most widely-used methods to determine the relationships among variables. Furthermore, a method proposed to test a unit root based on the periodogram ordinates has certain advantages over conventional tests. Periodograms can be calculated without any model specification and the exact distribution under the assumption of a unit root is obtained. For higher order processes the distribution remains the same asymptotically. In this study, in order to indicate advantages over conventional test of periodograms, we are going to examine a possible relationship between tourism and economic growth during the period 1999:01-2010:12 for Turkey by using periodogram method, Johansen’s conditional maximum likelihood method, Engle and Granger’s ordinary least square method.

Keywords: cointegration, economic growth, periodogram ordinate, tourism

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Authors: Anna Ghosh, Dominic Shields, Ceri McIntosh, Stephen Crank

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A 29-year-old male was a referral to the maxillofacial unit following a referral from his general dental practitioner via a routine pathway regarding a large periapical lesion on the LR4 with root resorption. The patient was asymptomatic, the LR4 vital and unrestored, and this was an incidental finding at a routine check-up. The patient's past medical history was unremarkable. Examination revealed no extra or intra-oral pathology and non-mobile teeth. No focal neurology was detected. An orthopantogram demonstrated a well-defined unilocular corticated radiolucency associated with the LR4. The root appeared shortened with the radiolucency between the root and a radio-opacity, possibly representing the displacement of the apical tip of the tooth. It was recommended that the referring general practitioner should proceed with orthograde root canal therapy, after which time exploration, enucleation, and retrograde root filling of the LR4 would be carried out by a maxillofacial unit. The patient was reviewed six months later where, due to the COVID-19 pandemic, the patient had been unable to access general dental services for the root canal treatment. He was still entirely asymptomatic. A one-year review was planned in the hope this would allow time for the orthograde root canal therapy to be completed. At this review, the orthograde root canal therapy had still not been completed. Interestingly, a repeat orthopantogram revealed a significant reduction in size with good bony infill and a significant reduction in the size of the lesion. Due to the ongoing delays with primary care dental therapy, the patient was subsequently internally referred to the restorative dentistry department for care. The patient was seen again by oral and maxillo-facial surgery in mid-2022 where he still reports this tooth as asymptomatic with no focal neurology. The patient's history was fully reviewed, and noted that 15 years previously, the patient underwent open reduction and internal fixation of a left angle of mandible fracture. Temporary IMF involving IMF screws and fixation wires were employed to maintain occlusion during plating and subsequently removed post-operatively. It is proposed that the radiolucency was, as a result of the IMF screw placement, penetrating the LR4 root resulting in resorption of the tooth root and development of a radiolucency. This case highlights the importance of careful screw size and physical site location, and placement of IMF screws, as there can be permeant damage to a patient’s dentition.

Keywords: facial trauma, inter-maxillary fixation, mandibular radiolucency, oral and maxillo-facial surgery

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Authors: Kari Saarelainen, Marko Jantti

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IT service trending of root causes of service incidents and problems is an important part of proactive problem management and service improvement. Human error related root causes are an important root cause category also in IT service management, although it’s proportion among root causes is smaller than in the other industries. The research problem in this study is: How root causes of incidents related to human errors should be categorized in an ITSM organization to effectively support service improvement. Categorization based on IT service management processes and based on Human Factors Analysis and Classification System (HFACS) taxonomy was studied in a case study. HFACS is widely used in human error root cause categorization across many industries. Combining these two categorization models in a two dimensional matrix was found effective, yet impractical for daily work.

Keywords: IT service management, ITIL, incident, problem, HFACS, swiss cheese model

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Authors: A. Ozkose

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This study was conducted to determination of yield and yield components of some fodder beet types (Amarilla Barres, Feldherr, Kyros, Magnum, and Rota) under the Konya region conditions. Fodder beet was obtained from the Selcuk University, Faculty of Agriculture, at 2006-2007 season and the experiment was established in a randomized complete block design with three replicates. Differences among the averages of the fodder beet cultivars are statistically important in terms of all the characteristics investigated. Leaf attitude value was 1.2–2.2 (1=erect; 5= prostrate), root shape scale value was (1=spheroidal – 9=cylindrical), root diameter 11.0–12.2 cm, remaining part of root on the ground was 6.3–13.7 cm, root length was 21.4 – 29.6 cm, leaf yield 1592 – 1917 kg/da, root yield was 10083–12258 kg/da, root dry matter content was %8.2– 18.6 and root dry matter yield was 889–1887 kg/da. As a result of the study, it was determined that fodder beet cultivars are different conditions in terms of yield and yield components. Therefore, determination of appropriate cultivars for each region affect crop yield importantly.

Keywords: fedder beet, root yield, yield components, Konya, agriculture

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Authors: Nooshin Salari, Viliam Makis, Jane Doe

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This paper presents a maintenance policy for a system consisting of two units. Unit 1 is gradually deteriorating and is subject to soft failure. Unit 2 has a general lifetime distribution and is subject to hard failure. Condition of unit 1 of the system is monitored periodically and it is considered as failed when its deterioration level reaches or exceeds a critical level N. At the failure time of unit 2 system is considered as failed, and unit 2 will be correctively replaced by the next inspection epoch. Unit 1 or 2 are preventively replaced when deterioration level of unit 1 or age of unit 2 exceeds the related preventive maintenance (PM) levels. At the time of corrective or preventive replacement of unit 2, there is an opportunity to replace unit 1 if its deterioration level reaches the opportunistic maintenance (OM) level. If unit 2 fails in an inspection interval, system stops operating although unit 1 has not failed. A mathematical model is derived to find the preventive and opportunistic replacement levels for unit 1 and preventive replacement age for unit 2, that minimize the long run expected average cost per unit time. The problem is formulated and solved in the semi-Markov decision process (SMDP) framework. Numerical example is provided to illustrate the performance of the proposed model and the comparison of the proposed model with an optimal policy without opportunistic maintenance level for unit 1 is carried out.

Keywords: condition-based maintenance, opportunistic maintenance, preventive maintenance, two-unit system

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Authors: Jonardan Koner, Basabi Bhattacharya, Avinash Purandare

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The study is focused to find out the impact of infrastructural investment on economic development in Indian states. The study uses panel data analysis to measure the impact of infrastructural investment on Real Gross Domestic Product in Indian States. Panel data analysis incorporates Unit Root Test, Cointegration Teat, Pooled Ordinary Least Squares, Fixed Effect Approach, Random Effect Approach, Hausman Test. The study analyzes panel data (annual in frequency) ranging from 1991 to 2012 and concludes that infrastructural investment has a desirable impact on economic development in Indian. Finally, the study reveals that the infrastructural investment significantly explains the variation of economic indicator.

Keywords: infrastructural investment, real GDP, unit root test, cointegration teat, pooled ordinary least squares, fixed effect approach, random effect approach, Hausman test

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Authors: Mingyue Sheng, Basil Sharp

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Greenhouse gas (GHG) emissions from national transport account for the largest share of emissions from energy use in New Zealand. Whether the environmental Kuznets curve (EKC) relationship exists between environmental degradation indicators from the transport sector and economic growth in New Zealand remains unclear. This paper aims at exploring the causality relationship between CO₂ emissions from the transport sector, fossil fuel consumption, and the Gross Domestic Product (GDP) per capita in New Zealand, using annual data for the period 1977 to 2013. First, conventional unit root tests (Augmented Dickey–Fuller and Phillips–Perron tests), and a unit root test with the breakpoint (Zivot-Andrews test) are employed to examine the stationarity of the variables. Second, the autoregressive distributed lag (ARDL) bounds test for co-integration, followed by Granger causality investigated causality among the variables. Empirical results of the study reveal that, in the short run, there is a unidirectional causality between economic growth and transport CO₂ emissions with direction from economic growth to transport CO₂ emissions, as well as a bidirectional causality from transport CO₂ emissions to road energy consumption.

Keywords: economic growth, transport carbon dioxide emissions, environmental Kuznets curve, causality

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Authors: Michal Spilacek, Marian Brazdil, Otakar Stelcl, Jiri Pospisil

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This paper shows an experimental testing of a small unit for combustion of solid fuels, such as charcoal and wood logs, that can provide electricity. One of the concepts is that the unit does not require a qualified personnel for its operation. The unit itself is composed of two main parts. The design requires a heat producing stove and an electricity producing thermoelectric generator. After the construction the unit was tested and the results shows that the emission release is within the legislative requirements for emission production and environmental protection. That qualifies such unit for indoor application.

Keywords: micro-cogeneration, thermoelectric generator, biomass combustion, wood stove

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Authors: Akhmadjon Sultanov, Eun-Ho Lee, Hye-Jin Park, Young-Je Cho

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This study tested the anti-inflammatory effect of wild indigo (Baptisia tinctoria) root in Raw 264.7 cells. We prepared two extracts of B. tinctoria; one in water and the other in 50% ethanol. Then we evaluated the toxicities of the B. tinctoria root extracts at 10 to 100 mg mL-1 concentrations in raw 264.7 cells and observed 80% cell viability. The anti-inflammatory effect of B. tinctoria root extract in lipopolysaccharide (LPS)-stimulated Raw 264.7 cells were observed with concentrations at 10, 30, and 50 μg mL-1. The results showed that 77.27-66.82% of nitric oxide (NO) production was inhibited by 50 μg mL-1 B. tinctoria root extract. The protein expression of Inducible NO synthase (iNOS) expression dramatically decreased by 93.14% and 52.65% in raw 264.7 cells treated with water and ethanol extracts of B. tinctoria root, respectively. Moreover, cyclooxygenase-2 (COX-2) protein expression decreased by 42.85% and 69.70% in raw 264.7 cells treated with water and ethanol extracts of B. tinctoria root, respectively. Furthermore, the mRNA expression of pro-inflammatory markers, such as tumor necrosis factor-alpha, interleukin-1β, interleukin-6, monocyte chemoattractant protein-1, and prostaglandin E synthase 2, was significantly suppressed in a concentration-dependent manner. Additionally, the B. tinctoria root extracts effectively inhibited enzymes involved in physiological activities. The B. tinctoria root extracts showed excellent anti-inflammatory effects and can be used as a functional material for biological activities.

Keywords: cytokine, macrophage, pro-inflammatory, protein expression, real-time PCR

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Authors: Rakiya Abba

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This paper investigates the effect of the money supply, exchange and interest rate on economic growth in Nigeria through the application of Augmented Dickey-Fuller technique in testing the unit root property of the series and Granger causality test of causation between GDP, money supply, the exchange, and interest rate. The results of unit root suggest that all the variables in the model are stationary at 1, 5 and 10 percent level of significance, and the results of Causality suggest that money supply and exchange granger cause IR, the result further reveals two – way causation existed between M2 and EXR while IR granger cause GDP the null hypothesis is rejected and GDP does not granger cause IR as indicated by their probability values of 0.4805 and confirmed by F-statistics values of 0.75483. The results revealed that M2 and EXR do not granger causes GDP, the null hypothesis is accepted at 75percent 18percent respectively as indicated by their probability values of 0.7472 and 0.1830 respectively; also, GDP does not granger cause M2 and EXR. The Johansen cointegration result indicates that despite GDP does not granger cause M2, IR, and EXR, but there existed 1 cointegrating equation, implying the existence of long-run relationship between GDP, M2 IR, and EXR. A major policy implication of this result is that economic growth is function of and money supply and exchange rate, effective monetary policies should direct on manipulating instruments and importance should be placed on justification for adopting a particular policy be rationalized in order to increase growth in economy

Keywords: economic growth, money supply, interest rate, exchange rate, causality

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Authors: Hailemariam Solomon, Taye Tadesse, Daniel Nadew, Firezer Girma

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Sorghum is an important crop in semi-arid regions and has shown resilience to drought stress. However, recurrent drought is affecting its productivity. Therefore, it is necessary to explore genes that contribute to drought stress adaptation to increase sorghum productivity. The aim of this study is to evaluate and determine the effect of root system traits, specifically root angle, on drought stress adaptation and grain yield performance in sorghum genotypes. A total of 428 sorghum genotypes from the Ethiopian breeding program were evaluated in three drought-stress environments. Field trials were conducted using a row-column design with three replications. Root system traits were phenotyped using a high-throughput phenotyping platform and analyzed using a row-column design with two replications. Data analysis was performed using R software and regression analysis. The study found significant variations in root system architecture among the sorghum genotypes. Non-stay-green genotypes had a grain yield ranging from 1.63 to 3.1 tons/ha, while stay-green genotypes had a grain yield ranging from 2.4 to 2.9 tons/ha. The analysis of root angle showed that non-stay-green genotypes had an angle ranging from 8.0 to 30.5 degrees, while stay-green genotypes had an angle ranging from 12.0 to 29.0 degrees. Improved varieties exhibited angles between 14.04 and 19.50 degrees. Positive and significant correlations were observed between leaf areas and shoot dry weight, as well as between leaf width and shoot dry weight. Negative correlations were observed between root angle and leaf area, as well as between root angle and root length. This research highlights the importance of root system architecture, particularly root angle traits, in enhancing grain yield production in drought-stressed conditions. It also establishes an association between root angle and grain yield traits for maximizing sorghum productivity.

Keywords: roor sysytem architecture, root angle, narrow root angle, wider root angle, drought

Procedia PDF Downloads 47

Authors: Rahim Ada, Zamari Temory, Hasan Dalgic

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Germination and seedling responses of seven safflower seed genotypes (Dinçer, Remzibey, Black Sun2 cultivars and A19, F4, I1, J19 lines) to different salinity concentrations (0, 5, 10, and 20 g l-1) and temperatures (10 and 20 oC) evaluated in Completely Randomized Factorial Designs in Department of Field Crops of Selcuk University, Konya, Turkey. Seeds in the control (distilled water) had at 10 and 20 oC the highest germination percentage (93.88 and 94.32 %), shoot length (4.60 and 8.72 cm), root length (4.27 and 6.54 cm), shoot dry weight (22.37 mg and 25.99 mg), and root dry weight (2.22 and 2.47 mg). As the salt concentration increased, values of all characters were decreased. In this experiment, in 20 g l-1 salt concentration found germination percentage (21.28 and 26.66 %), shoot (1.32 and 1.35 cm) and root length (1.04 and 1.10 cm), shoot (8.05 mg and 7.49 mg) and root dry weight (0.83 and 0.98 mg) at 10, and 20 oC.

Keywords: safflower, NaCl, temperature, shoot and root length, salt concentration

Procedia PDF Downloads 263

Authors: Asmaa Al Shafiee, Erdin Ibraim

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Stabilizing slopes by using vegetation is considered as a cost-effective and eco-friendly alternative to the conventional methods. The main aim of this study is to investigate the mechanical effect of analogue root systems on the shear strength of different soil types. Three objectives were defined to achieve the main aim of this paper. Firstly, explore the effect of root architectural design to shear strength parameters. Secondly, study the effect of root area ratio (RAR) on the shear strength of two different soil types. Finally, to investigate how different kinds of soil can affect the behavior of the roots during shear failure. 3D printing tool was used to develop different analogue tap root models with different architectural designs. Direct shear tests were performed on Leighton Buzzard (LB) fraction B sand, which represents a coarse sand and Huston sand, which represent medium-coarse sand. All tests were done with the same relative density for both kinds of sand. The results of the direct shear test indicated that using plant roots will increase both friction angle and cohesion of soil. Additionally, different root designs affected differently the shear strength of the soil. Furthermore, the directly proportional relationship was found between root area ratio for the same root design and shear strength parameters of soil. Finally, the root area ratio effect should be combined with branches penetrating the shear plane to get the highest results.

Keywords: leighton buzzard sand, root area ratio, rooted soil, shear strength, slope stabilization

Procedia PDF Downloads 128

Authors: Kolawole F. Farinloye, Samson O. Ojo

Abstract:

Two Columbiformes species were recently introduced to the newly established Awba Dam Tourism Centre [ADTC], hence there is need to investigate the effect of seasonal variation on these species with respect to hematological composition. Blood samples were obtained from superficial ulna vein of the 128 apparently healthy C. livia and C. guinea into tubes containing EDTA as anticoagulant. Thin blood smears (TBS) were prepared, stained and viewed under microscope. Values of Red Blood Cell (RBC) count, White Blood Cell (WBC) count, cholesterol (CH), Uric Acid (UA), Protein (PR), Mean Corpuscular Volume (MCV), Haemoglobin Content (HB), Blood Volume (BV), Plasma Glucose (PG) and Length/Width (L/W) ratio of red blood cells were assessed. The procedure was carried out on a seasonal basis (wet and dry seasons of 2013-2014). Data was analyzed using descriptive and inferential statistics. Lymphocyte count for C. livia was F3, 161 = 13.15, while for C. guinea was F3, 178 = 13.15. Heterophil, H/L ratio and Muscle score values for both species were (rs = -0.38, rs = -0.44), (rs = 0.51, rs = 0.31) (4, 3) respectively. Analyses also demonstrated a low WBC to RBC ratio (0.004: 25.3) in both species during the wet season compared to dry season, respectively. L/W varied significantly among sampling seasons i.e. wet (19.1% of BV, 12.6% of BV, 0.1% of BV) and dry (18.9% of BV, 12.7% of BV, 0.08% of BV). The level of HB in wet season (19.20±8.46108) is lower compared to dry season (19.70±8.48762). T-test also showed (wet=15.625, 0.111), (dry=12.125, 0.146) respectively, hence there is no association between species and haematological parameters. Species introduced were found to be haematologically stable. Although there were slight differences in seasonal composition, however this can be attributed to seasonal variation; suggesting little or no effect of seasons on their blood composition.

Keywords: seasonal variation, Columbiformes, Awba Dam tourism centre, University of Ibadan, Ibadan

Procedia PDF Downloads 303

Authors: Muhammad Ashfaq, Muhammad Saleem Haider, Muhammad Ali, Muhammad Sajjad, Amna Ali, Urooj Mubashar

Abstract:

Phenotypic diversity was confirmed by measuring different morphological traits i.e. seed traits (seed length, seed width, seed thickness, seed length-width ratio, 1000 grain weight) and root-shoot traits (shoot length, root length, shoot fresh weight, root fresh weight, root-shoot ratio, root numbers and root thickness). Variance and association study of desirable traits determine the genotypic differences among the rice germplasm. All the traits showed significant differences among the genotypes. The traits were studied in Randomized complete block design (RCBD) at different water levels. Some traits showed positive correlation with each other and beneficial for increasing the yield and production of the crop. Seed thickness has positive correlation with seed length and seed width (r= 0.104**, r=0.246**). On the other hand, various root shoot traits showed positive highly significant association at different water levels i.e. root length, fresh root weight, root thickness, shoot thickness and root numbers. Our main focus to study the performance/correlation of root shoots traits under stress condition. Fresh root weight, shoot thickness and root numbers showed positive significant association with shoot length, root length, fresh root and shoot weight (r=0.2530**, r=0.2891**, r=0.4626**, r=0.4515**, r=0.5781**, r=0.7164**, r=0.0603**, r= 0.5570**, r=0.5824**). Long root length genotypes favors and suitable for drought stress conditions and screening of diverse genotypes for the further development of new plant material that performing well under different environmental conditions. After screening genetic diversity of potential rice, lines were studied to check the polymorphism by using some SSR markers. DNA was extracted, and PCR analyses were done to study PIC values and allelic diversity of the genotypes. The main objective of this study is to screen out the genotypes on the basis of various genotypic and phenotypic traits.

Keywords: rice, morphological traits, association, germplasm, genetic diversity, water levels, variation

Procedia PDF Downloads 299