Showing 249 results for Tc
Volume 0, Issue 0 (1-2024)
Abstract
Microcredit plays a vital role in the food security of rural households. However, to the best of our knowledge, the effects of microcredit on improving the food security of households have not yet been well studied and understood in Iran. Therefore, this study aims to investigate the success of microcredit programs on enhancing the food security of rural households in Zehak county using the propensity score matching method and bootstrap algorithm. For this purpose, two food security indices, including the Household Food Insecurity Access Scale (HFIAS) and the Food Consumption Score (FCS), are used. The results revealed that 100% of the households face food insecurity. The prevalence of food insecurity was 20.0%, 42.5%, and 37.5% for mild, moderate, and severe food insecurity, respectively. In addition, 30% of households are in poor status of food consumption. Our findings emphasize the positive and significant role of microcredit in improving food security. The results showed that microcredit decreased the HFIAS index of the recipient households by 24.31-27.81% and increased the FCS index by 25.87-31.45%. Therefore, policy-makers and decision-makers should promote and strengthen governmental and non-governmental organizations providing microcredit. It is also recommended to provide information and reduce collateral restrictions to increase households' access to microcredit.
Volume 0, Issue 0 (12-2024)
Abstract
Aim and Introduction:
A growing body of research highlights the bidirectional relationship between conflict and economic performance. Findings indicate that economic decline—particularly severe recessions that reduce income levels, exacerbate inequalities, and intensify widespread economic distress—can fuel social unrest and internal conflicts. Periods characterized by a high risk of government collapse are associated with significantly lower rates of economic growth compared to more politically stable periods. Although such violent events may not occur frequently, they are prevalent worldwide and have affected numerous countries.
The Middle East, in particular, has long been afflicted by internal unrest, persistent conflicts, and intra- and intergovernmental tensions—all of which adversely influence national economies. Political economy literature underscores a complex interplay between political forces and economic direction, suggesting that political instability can disrupt economic continuity and hinder economic growth—a central indicator of national economic performance.
Accordingly, the primary objective of this study is to model the effects of political instability and conflict on economic growth in a sample of developing and developed countries, namely Iran, Iraq, Saudi Arabia, Russia, the United States, India, China, and Canada.
Methodology:
This study adopts a descriptive-analytical approach with practical applications, relying on secondary data collected through documentary research. The analytical method employed is the Bayesian Markov Switching Panel Regression, which effectively captures symmetric and asymmetric effects across different economic regimes.
The selected countries—spanning both developed and developing contexts—include Iran, Iraq, and Saudi Arabia, which have historically faced political tension and oil revenue fluctuations, as well as Russia, Canada, the United States, India, and China. The inclusion of India and China reflects their status as major global energy consumers. These countries were chosen based on their exposure to international tensions and their substantial influence on the global energy landscape.
The study period covers 1990 to 2020. The Markov switching panel framework enables the model to differentiate the impact of explanatory variables across distinct economic regimes. For instance, political stability may influence economic growth differently during recessionary periods compared to times of economic expansion. The variables analyzed include conflict intensity, political instability, oil income, population growth, foreign direct investment, life expectancy, government expenditure, budget deficits, trade openness, and the governance quality index.
Results and Discussion:
The analysis reveals that conflict and economic instability exert statistically significant effects on economic growth across both recession and growth regimes. In the recession regime, the coefficients for conflict and instability are 0.17% and 0.12%, respectively, while in the growth regime, they are slightly lower at 0.16% and 0.11%. Although both variables remain significant in both regimes, their influence is more pronounced during recessions, implying that political instability and conflict are more detrimental to growth when the economy is already underperforming.
These findings are consistent with prior research by Ashenfelter and Troeger (2006), Gaybulov and Sandler (2019), and Bart et al. (2021). Additionally, variables such as oil income, population growth, foreign direct investment, life expectancy, government expenditure, trade openness, and governance quality all exhibit positive and statistically significant effects on economic growth in both regimes.
The dominant economic regime identified in the study is the growth regime. Notably, with the exception of Iraq, Iran, and Saudi Arabia, the other countries analyzed have been experiencing economic growth in recent years. This observation underscores the correlation between political stability and sustained economic performance.
Conclusion:
The findings of this research emphasize the critical role of political stability in fostering a robust and resilient economic environment. A stable political climate is not only essential for social cohesion but also serves as a prerequisite for sustained economic growth and development. Policymakers are thus encouraged to invest in institutional reforms, infrastructure development, and inclusive governance frameworks that enhance citizens’ participation in decision-making processes. These measures can significantly contribute to both political stability and long-term economic prosperity in the countries under study.
Volume 0, Issue 2 (8-2011)
Abstract
A bench scale aerobic sequencing batch reactor (SBR) was evaluated in terms of its potential to treat synthetic dairy wastewater. The 2-l plexiglass bioreactor was supplied with oxygen via a fine bubble air diffuser, fed with synthetic dairy wastewater under various operational conditions. To analyze the process, three significant independent variables — influent chemical oxygen demand (COD), mixed liquor volatile suspended solids (MLVSS), and aeration time — were assessed. Three dependent process and quality parameters (as process responses) were also evaluated: total COD removal efficiency, sludge volume index (SVI) and final pH. The experiments were based on a central composite design (CCD) and analyzed using response surface methodology (RSM). The treatment was limited to the following concentration regimes: COD (1000, 3000 and 5000 mg/l), MLVSS (3000, 5000 and 7000 mg/l) and aeration time (2, 10 and 18 h). Maximum COD removal efficiency (of 96.5%) was obtained for an influent with the following characteristics: CODin: 3000 mg/l, MLVSS 5000 mg/l, and aeration time of 18 h. The study demonstrated the capability of aerobic SBRs for high COD removal from dairy industrial wastewater. Easy operation, low cost, and minimal sludge bulking condition were some of advantages of the SBR system as an option for biological treatment of medium-strength industrial wastewater. The present study provides valuable information about relationships between quality and process parameters for different values of operating variables.
Volume 0, Issue 2 (8-2011)
Abstract
This study evaluates changes in species composition, catch, and CPUE of three species of kilkas in the Caspian Sea from 1961 to 2009. The effects of fluctuations in sea level rise and fall on the catch of kilka as well as the impacts of a recent invasion by Mnemiopsis leidyi (Ctenophora) were assessed in terms of species composition and CPUE of kilkas in the Iranian coastal region of the Caspian Sea. We found a negative correlation between long-term sea level changes and total catch (R2 = –0.56; P<0.001, which significantly declined in 1995 when the sea level increased to its highest level. Comparing catch per unit effort (CPUE) values during the pre-invasion (1996–1999) and post-invasion (2000–2009) periods indicated significant declines in anchovy and bigeye kilka, while common kilka increased significantly after the ctenophore invasion. During 2000–2009 overfishing, together with various environmental impacts following the introduction of Mnemiopsis, were major factors that contributed to changes in species composition and the collapse of kilka stocks in the Caspian Sea.
Volume 1, Issue 1 (5-2011)
Abstract
Measuring government is among the major challenges faced by public policy makers in any country. The origin of measuring the government performance is the managerial paradigm of political system. Public policies are reflections of government management. For measuring policy outcomes, a measurement system must be designed. The public value model can be used for measuring policy outcomes. In this paper, a model for is proposed measuring public policy performance based public value model.
Volume 1, Issue 2 (6-2013)
Abstract
Recently the previous Caspian ecosystem is in a catastrophic condition which caused changes in the absolute and relative abundance of the commercially important Caspian kutum (Rutilus frisii kutum) in Iranian waters. The paper presents estimates of yield-per-recruit and spawning biomass-per-recruit under various harvest strategies of Fmax, F0.1, F30%. It proposes a method for estimating acceptable biological catch (ABC) that accounts for large differences in the quality and quantity of information and available data. The current average Y/R (with F=0.61/y, and tc=3.2 y) was 218.3 g per recruit, which indicates that the fishery is operating below the maximum Y/R at 236.9 g when tc = 3.5 y. The Y/R was the highest at Fmax and F0.1, when tc = 4 y (244.8 g and 214.2 g), respectively. The F30% value was 0.85/y at tc of 4 y with the SB/R of 338.3 g. The Fcurrent (0.61/y at current tc is 3.2 y) is higher than the corresponding reference points, F0.1 (0.47/y) and F30% (0.46/y). The ABC of kutum was estimated at 7,850 mt in 2009-2010.
Volume 2, Issue 4 (3-2014)
Abstract
The effects of valerian, Valerian officinalis, and clove, Eugenia caryophylla, extracts as anesthetic chemicals were investigated on Panga siussutchi (12.95±0.92 mm, 16.85 ± 3.52 g). The fish were divided in 6 groups, each including 5 individuals and exposed to various concentrations (2, 3 and 4 g/lit) of clove and/or valerian extract. The mean time to induce sedition, the mean time to return and the mean number of opercular gill pulses to sedate and recover were measured. For both groups, the mean time to sedation was decreased by increasing the dose of the extract. In general, the mean time to onset of anesthesia for clove group was significantly lower than valerian. The mean number of opercular gill pulses during the sedation time was not significantly changed between different dose of clove, while it declined significantly by elevating the valerian doses (p<0.05). There was no mortality in both groups. Although V. officinalis extract could cause sedation in the fish, it needed relatively longer time to affect than clove, so it may not be a useful compound for sedation in P. siussutchi.
Volume 2, Issue 4 (3-2019)
Abstract
The current study is based on synthesis a low cost carbon aerogel with improved properties and thermal insulator approach. In this work cheap novolac resin are used as a raw material for producing polymer aerogel by ambient drying method; then the coal tar pitch is added to samples by immerging them in pitch solution. In next step novolac-pitch polymer aerogels is converted to carbon nano-structure aerogels by pyrolysis heat treatment at inert atmosphere. The results proved, nano-structured aerogels with predictable density will be achieved by this method; also by studying on microstructure and morphology of aerogels it founded these aerogels have high porosity, low density(about 0.1-0.4 g/cm3) and high specific surface area (about 600 m2/g). The charring pitch was a lot and using of it made improved thermal properties that resulted in at least 100s delay in increasing temperature in time-temperature history test; as a result a high performance thermal insulator achieved.
Volume 3, Issue 1 (12-2003)
Abstract
Label switching technology is a flexible and high performance method for forwarding layer three packets that are mapped to layer two flows. Each label switch router, LSR, needs a specific label for every flow, where the number of labels depends on the mapping and granularity of flows. Data and control driven methods are the most significant and popular methods in label mapping policy. The above mentioned methods have been investigated. The possible pitfalls of each method are identified for an optimal operation and performance. One of the most significant difficulties is the rate of flows creation and deletion. This issue is vital in both scalability and implementation of networks and is more significant in data driven methods. In this paper, a new flow-Subnet Flow-has been proposed which increases the performance in data driven methods. The simulation results show fair improvement in performance and validity of the Subnet Flow.
Volume 3, Issue 2 (6-2012)
Abstract
This article studies the perceptual correlates of lexical stress in Persian. The minimal stress pair // was used as the stimulus token, and the values of duration, overall intensity, spectral balance and F0 were varied in several steps both in the accented and de-accented conditions. 20 native Persian speakers were asked to identify the stressed tokens in a force-choice perception experiment. The results showed that in the accented condition, F0 is the most reliable perceptual correlate of stress. Other correlates are in additive interaction with F0. In de-accented condition, stress is strongly cued by duration, while among the other correlates, spectral balance provides stronger stress cues than overall intensity.
Volume 3, Issue 3 (9-2014)
Abstract
In 2010- 2012 surveys, witches'- boom disease of tomato was observed in Borazjan area (Bushehr province, Iran). Agent of the disease was transmitted from tomato to tomato and eggplant by grafting and to Madagascar periwinkle via dodder inoculation, inducing phytoplasma-type symptoms in inoculated plants. Presence of phytoplasma in naturally affected tomatoes and all symptomatic graft and dodder inoculated plants was confirmed by direct and nested polymerase chain reactions (PCR) using primer pairs P1/P7 and R16F2n/R16R2. BLAST search and phylogenetic analysis of 16SrDNA showed that detected phytoplasma belonged to peanut witches'- broom (16SrII) group. Phylogenetic analysis, percent homology and virtual RFLP indicated that, as a member of 16SrII group, Borazjan tomato witches’- broom (BTWB) phytoplasma together with Bushehr eggplant and alfalfa witches’- broom (BEWB and BAWB, respectively) phytoplasmas were classified with Candidatus Phytoplasma australasia, a phytoplasma related to 16SrII-D subgroup. Based on the same analysis, BTWB, BEWB and BAWB phytoplasmas were differentiable from three other Iranian 16SrII related phytoplasmas associated with alfalfa witches'- broom diseases in Yazd and Fars provinces and lime witches'- broom disease in southern Iran.This is the first report of tomato witches'- broom disease and characterization of its associated phytoplasma in Iran.
Volume 4, Issue 1 (1-2016)
Abstract
Background: The comprehensive evaluation program of the health system in higher education is a strategic plan in line with the goals of health reform program. The planning levels are based on 12 general policies. As professors of medical universities have an important role in public health promotion, this study aimed to identify the outcomes of faculty development at medical universities in Northern part of Iran, based on evolution and innovation program of medical education.
Methods: This qualitative research was conducted using Grounded Theory Approach during 2015-2016. The research population consisted of 22 faculty members of medical universities in Northern part of Iran. Sampling was performed by a purposive sampling method for those who had responsibilities at university or college.
Results: The results of the obtained data suggested two main themes: the internal university outcomes (i.e. Promotion of education quality at universities) and external university outcomes (i.e. Public health promotion).
Conclusion: It is suggested to education policy makers to apply a more accurate and systematic plan in order to achieve development and growth of their faculty members; so, the effectiveness and efficiency of faculty members and consequently higher education will be promoted.
Volume 4, Issue 3 (9-2018)
Abstract
Aims: Pertussis is an important vaccine preventable disease. It is still a major cause of infant morbidity and mortality in the world. Although the incidence of pertussis was successfully reduced after vaccination, the resurgence of pertussis has been reported in many countries even with high vaccination coverage. Genetic variation in virulence factors is one of the important causes for pertussis reemergence. We investigated genetic characteristics and allele types of 3 important virulence associated genes, including ptxC, tcfA, and fhaB in clinical B. pertussis isolates collected from different provinces of Iran and vaccine strains.
Materials & Methods: Genomic DNA was extracted and ptxC, tcfA, and fhaB gene regions were amplified, using specific PCR primer. DNA sequencing was performed and data were analyzed.
Findings: ptxC2, tcfA2, and fhaB1 were the dominant alleles with 87.5%, 97.5%, and 97.5% frequencies, respectively. Vaccine strains B. pertussis 134 and B. pertussis 509 contain the genotypes ptxC2- tcfA2-fhaB1 and ptxC2- tcfA2-fhaB1.
Conclusion: Results for dominant alleles in ptxC2, tcfA2, and fhaB1 genes in Iran are consistent with dominant alleles of other countries such as Netherland, Finland, and Italy. It seems that ptxC2, tcfA2, and fhaB1 are the dominant circulating alleles in many countries after vaccination period, while vaccine strains have different alleles occasionally. More reported cases in recent years despite high coverage vaccination in Iran and genetic distances between clinical and vaccine strains suggest that antigenic changes in virulence factors possibly have an important role in the survival and evolution of the bacteria.
Volume 4, Issue 3 (12-2020)
Abstract
Research subject: It is not an easy task to get a suitable model of polymerization due to complex mechanism and kinetic of such processes. Polymerization temperature, as an intermediate variable between determining final polymer properties, is a good selection to be controlled. Fuzzy logic has ability to be applied to processes with unknown or less informed dynamics.
Research approach: In this research, control of semi batch poly(ethylene terephthalate) reactor temperature was studied. To do so, error and error variation were calculated using measured reactor temperature. Error and error variation were fuzzified using triangular membership functions. Five and three fuzzy sets were introduced to fuzzify error and error variation, respectively. Hence, fifteen rules were defined. Five fuzzy sets were defined to quantify these fifteen rules. Weight average defuzzification method was applied to calculate necessary heat to the reactor. Poly(ethylene terephthalate) was synthesized in a semi batch reactor based on a two steps method. It is possible to monitor temperature, pressure, rotation speed and mixing torque in this set up.
Main results: Produced water during esterification determines reaction advancement. In polycondensation step, mixing torque determines end of the process. Linguistic based fuzzy rules were applied to both steps. Reference temperatures were 230oC and 260oC, respectively. Reactor temperature was controlled with 1-2oC precision. Control logic was applied using C#.net real time programming.
Volume 4, Issue 4 (12-2022)
Abstract
An analysis of the state of Iran's water resources shows that hydro-political challenges have shifted from the national scale to the sub-national scale (at the catchment level) and the conflict of interests of users has led to a contradiction in the approach of agents, especially in times of drought. Meanwhile, Karkheh catchment in Khuzestan feeds by Kashkan river in Lorestan province. On the other hand, climate change and Kashkan floods have often been associated with losses. The basic agricultural livelihood of Delfan city and the prevention of floods have made the construction of Gaushmar dam on Kashkan inevitable. The construction of this dam has reduced the volume of water entering the downstream cities of the dam and the Karkheh catchment in Khuzestan, especially during dry seasons. The construction of this dam has led to the conflict of interests of the actors and the emergence of hydro-political challenges on a subsidence scale. The present article is applied and the methodology of the text is explanatory-analytic. The data and information required for the research were collected by library and field methods (interview). The result of the research showed that with the construction of Gaushmar Dam, hydro-political relations within the province (Lorestan) and extra-provincial relations between Khuzestan and Lorestan provinces have been brought hydro-political tension. The adaptation of these conflict of interests eventually led to a reduction in the height of the dam and the volume of water stored behind the dam due to the authorities’ policies.
Volume 4, Issue 5 (12-2015)
Abstract
Culture filtrates (CF) of two species of the nematophagous fungi, Arthrobotrys oligospora and Arthrobotrys conoidesat three concentrations (25%, 50% and 100%) of stock, were tested on the mortality of second stage juveniles (J2) and egg hatching rate of Meloidogyne incognita and Meloidogyne javanica. Results showed that the percent juvenile mortality was directly proportional to concentration of the filtrates. Egg hatching rate of these nematodes was inversely affected by increasing concentrations. Also CFs had various impacts on the mortality of J2 and egg hatching rate. In case of M. incognita maximum J2 mortality (28.98%) occurred after 24 hours of exposure to A. conoides filtrate at concentration of 100%. The minimum toxicity (12.5% J2 mortality) was recorded for A. oligospora at 25% filtrate concentration. At the same time, the highest rate of J2 mortality of M. javanica (19.18%) belonged to the 100% concentration of A. conoides, while minimum toxicity belonged to 25% concentration of A. oligospora causing 9.09% mortality. Maximum egg hatching rate for M. incognita (30.75%) belonged to control and minimum hatching rate (1.25%) belonged to 100% concentration of A. conoides. The highest hatching rate of M. javanica (36.25%)belonged to control and minimum hatching rate (1.25%) occurred at 100% concentration of A. conoides.
Volume 5, Issue 0 (0-2005)
Abstract
In this paper, we used a shape matching algorithm to recognize Farsi digits. For each sampled point on the contour of a shape, we obtain a descriptor showing the distribution of the other points of the contour, with respect to this point. Based on these descriptors, we find the corresponding points of the two contours and take the sum of their distances as a dissimilarity measure between two shapes. Then we define a geometric transformation that maps the sampled points of the one shape to the corresponding points of the other shape. The bending energy of this transform is taken as the second dissimilarity measure between two shapes. We optimized the parameters of the matching algorithm for the recognition of Farsi digits and used the method of minimum distance from the class prototypes for the recognition. In a test on a set of 1288 digits, we obtained a recognition rate of 89.9%. This result was obtained without any post processing
Volume 5, Issue 1 (3-2016)
Abstract
Pomegranate fruit moth (PFM), Apomyelois ceratoniae Zeller is a major pest of pomegranate in Iran. In this study, the effect of four diets including pistachio, pomegranate, semi-artificial and artificial diets were studied on biological parameters of PFM in a growth chamber under controlled conditions at 30 ± 2 °C, 65 ± 5% RH and 16:8 (L: D) h. The results demonstrated that the longest incubation period, larval developmental time and preimaginal development time was observed on artificial diet and the shortest was on the pomegranate. The highest and lowest body length of fifth instar larvae were observed on pistachio and artificial diet, respectively. The heaviest weight of third day pupae was recorded for the larvae that were reared on pistachio (0.0275 ± 0.0004 g) while the lightest was on artificial diet (0.0216 ± 0.0004 g). In the next experiment, the effect of four diets was considered to assess the efficiency of pheromone traps in a twenty year old pomegranate orchard cultivated with Malasse Yazdi cultivars. The effect of food on catch of traps showed a significant difference. The virgin PFM that were fed with pomegranate attracted more males. Also the traps caught the males mostly from 11:00 pm until 4:00 am, with the peak time between 23:00 and midnight. No significant difference was seen between diet and time of catch, indicating that starting or ending time and the maximum time of catch was not affected by the diets.
Volume 5, Issue 1 (3-2019)
Abstract
Arthropods were sampled on an early- and late-season crop of watermelon in the 2016 cropping season using motorized suction sampler swept along 5m length of the middle row of 20 experimental plots at Federal University Wukari. Specimens were sorted to morphotypes, feeding guilds and as dominant based on percentage relative abundance (RA) and frequency of occurrence (FO). Different species diversity indices were computed. The collections made on the early- and late-sown crops were compared using Jaccard’s Similarity index (Cj). Spatial distribution pattern of the dominant arthropods were determined using Taylor’s power law and Iwao’s patchiness regression. Results showed that collections on both crops were similar (Cj= 0.83). A total of 14,466 specimens sorted to 1 order (Araneae) in the class Arachnida and 64 species in 41 families and 8 orders in the class Hexapoda were collected. Data showed moderately high species diversity (H = 2.8-3.0), richness (R = 6.0-7.2), but low evenness (E = 0.26-0.39). Coleopterous insects (22 species), dominated by chrysomelids, were the most diverse and species-rich followed by hymenopterans, mainly formicids. Dominant arthropods (RA≥1.0 and FO≥25.0%) included Asbecesta nigripennis, Aulacophora africana, Philanthus triangulum (parasitoid of bee), Pheidole sp., Camponotus sp., Rhynocoris nitidulus and spiders. Most dominant arthropods were aggregated; dispersion varied with model used and crop season. Only 27.3% of the diverse and rich arthropods on watermelon at Wukari require pest management intervention and validation of their dispersion pattern in large-scale watermelon production.
Volume 5, Issue 3 (11-2020)
Abstract
Aim: Back pain is one of the most important public health problems among students especially among who carrying backpack to school. The aim of this study was to assess healthy spine-related behavior among these students.
Instruments and Method: A descriptive study was conducted on a random sample of students attending public elementary schools in Tehran, Iran. The students completed a questionnaire containing items on cognitive abilities sections of knowledge, outcome expectation beliefs, self- efficacy companied with a checklist to assess their skills on back care behaviors. The last section was about items regarding back care behaviors. All collected data entered to SPSS version 24 and analyzed.
Findings: In all, 204 students were entered into the study. The Mean (SD) of knowledge, Outcome expectation beliefs, Self- efficacy, Skills and Back care behaviors were as 4.71 ±1.40; 20.48 ± 6.44; 13.89 ± 4.44; 65.84 ± 16.16; and 20.94 ± 6.65 respectively.
Conclusion: The findings of this study suggest that the probably influencing factors on back care behaviors were not in optimal status. Accordingly, doing multi-central causative studies to confirm the results is strongly recommended.
