750 research outputs found
Effect of Different Tillage Methods on Soil Physical Properties, Quantitative and Qualitative Yield of Two Forage Maize Cultivars
One of the factors affecting the physical properties of soil and crops is tillage systems. The experiment was conducted in summer 2012 at the research farm of Islamic azad university. This study was performed by experiment a split plot in a randomized complete block design with three replications. The main factors in this study, four different tillage methods as a main factors and sub factors includes two maize varieties, including single cross 704 and maxima were considered. Also for soil physical properties statistical analysis, randomized complete block design was used. based on the results? different tillage methods on soil physical properties and yield of plants showed significant differences at 1%. Most of the yield was related to corn single cross 704 and twice of disc tillage in depth of 15-10 cm, with 88/18 tons per hectare. The greatest amount of soluble sugars and protein was obtained from corn single cross 704 with cultivator with blade and light disk with depth of 8 to 10 cm. thus it can be concluded that reduced tillage methods in dry and warm regions through Improve soil structure and retain moisture, resulting the yield of quantitative and qualitative of diffrent agricultural products will Increase. Keywords: soil, corn, physical properties, tillage methods, quantitative and qualitative yield
Saturation-Dependence of Dispersion in Porous Media
In this study, we develop a saturation-dependent treatment of dispersion in
porous media using concepts from critical path analysis, cluster statistics of
percolation, and fractal scaling of percolation clusters. We calculate spatial
solute distributions as a function of time and calculate arrival time
distributions as a function of system size. Our previous results correctly
predict the range of observed dispersivity values over ten orders of magnitude
in experimental length scale, but that theory contains no explicit dependence
on porosity or relative saturation. This omission complicates comparisons with
experimental results for dispersion, which are often conducted at saturation
less than 1. We now make specific comparisons of our predictions for the
arrival time distribution with experiments on a single column over a range of
saturations. This comparison suggests that the most important predictor of such
distributions as a function of saturation is not the value of the saturation
per se, but the applicability of either random or invasion percolation models,
depending on experimental conditions
Flexibility from local resources: Congestion management in distribution grids and carbon emission reductions
Flexibility from local energy systems has been discussed as a facilitator for the transition towards a more carbon-neutral energy system. Two use cases of this flexibility are congestion management in electricity distribution networks, and an individual-driven reduction of carbon footprints. However, for taping into this flexibility, effective incentive mechanisms and operation planning are essential. This licentiate thesis aims to provide new insights into two areas: 1) the design of market-based incentive mechanisms for congestion management in distribution grids, and 2) the operation planning of local flexible asset owners for reducing their carbon emission footprints.The first area focuses on challenges, design, and evaluation of local flexibility markets (LFMs) for congestion management in distribution grids. The utilized methods include literature review, field studies, scenario planning methods, and demonstration and simulation experiments.Results for identifying the challenges show that the most impactful and uncertain factors are the willingness and ability of end-users to participate in LFMs, and regulatory incentives for distribution system operators (DSOs). Moreover, five challenges are identified for LFM design including low market liquidity, reliability concerns, baselines, forecast errors at low aggregation levels, and the high cost of sub-meter measurements.An LFM design is proposed to address the challenges. The design is a triple horizon market structure including reservation, activation, and adjustment horizons which can support decision making of market participants and improve market liquidity and reliability. Adapted capacity-limitation products are proposed that are calculated based on net-load and subscribed connection capacity of end-users. The products can reduce conflict of interests, and administrative and sub-meter measurement costs related to delivery validation and baselines. Moreover, probabilistic approaches for calculating the cost and value of the products are proposed that can reduce the potential cost of forecast errors for market participants while providing insights on how the utility and cost of the products can be calculated.Evaluating the proposed design is an ongoing work utilizing simulations and real-life demonstrations. The most suitable congestion management solution can vary depending on the context and test-system. Therefore, the evaluation should include comparing the design with other congestion management solutions such as power tariffs. A comparison toolbox is proposed to be used by researchers and DSOs including a qualitative comparison framework and a reusable modeling platform for the quantitative comparison. Four cases are quantitatively compared using the toolbox on a sub-area of Chalmers campus testbed: i) LFM+PT+ET (i.e., considering the LFM, power tariff (PT), and energy cost (ET) simultaneously), ii) LFM+ET, iii) PT+ET, and iv) ET. The most recent results show that case (i), has the lowest number of congested hours. Moreover, congestions due to rebound effects from activating the LFM are observed. The comparison of cases (i) and (ii) suggests that enforcing power tariffs besides the LFM can reduce the rebound effects.The second area utilizes a multi-objective optimization model for identifying CO2 emission abatement strategies and their cost for Chalmers testbed local multi-energy system. The results of the case study show that the carbon emission footprint of the local system can be reduced by 20.8% with a 2.2% increase in the cost. The operation strategies for this purpose include more usage of biomass boilers in heat production, substitution of district heating and absorption chillers with heat pumps, and higher utilization of storage. The cost of the strategies ranged from 36.6-100.2 €/tCO2.This thesis can benefit system operators, flexibility asset owners, policy makers, and researchers dealing with local flexibility resources by offering insights into the challenges and proposing solutions and toolboxes for implementation and evaluation
Elucidating the genetic architecture of cystic kidney disease using whole genome sequencing
Cystic kidney disease (CyKD) is the commonest life-threatening monogenic disorder, causing great morbidity and mortality. Whilst there is believed to be a strongly monogenic architecture, an unbiased whole genome sequencing approach to understanding the underlying genetic architecture has never previously been attempted.
In this thesis I used statistical genetics and bioinformatics methodology to investigate the genetic architecture of CyKD as well as two other rare disorders, urinary stone disease (USD) and extreme early onset hypertension (EEHTN), using whole genome sequencing data from the 100,000 Genomes Project. I used population-based tools to assess the rare and common variant associations in diverse ancestry matched cohorts seeking enrichment of single nucleotide/indel and structural variants on a genome-wide and per-gene basis.
In all three disorders this improved our understanding of the underlying architecture. CyKD is shown to be strongly monogenic as expected but low-frequency and common variants are shown to play an important role in pathogenesis and causation of this disease, revealing a role for polygenic factors. The heritability of USD is shown to be heavily influenced by low-frequency variants in the sodium-phosphate transporter gene SLC34A3, which explains much of the missing heritability not detected by previous large-scale common variant association studies. This finding bridges the gap between the traditional thinking that USD is either monogenic or polygenic/environmental. Finally, EEHTN is shown to likely be an extreme manifestation of primary hypertension, with a strong polygenic basis.
These results support the idea that with better sequencing and larger biobanks, an omnigenic model of disease will become more demonstrable for a broader range of phenotypes, consistent with genotype-phenotype heterogeneity, variable expressivity and incomplete penetrance observed in all three diseases. Finally, I demonstrate that population level approaches traditionally used to study common disease are applicable and useful in rare disease research
Water Dynamics and the Effect of Static and Alternating Electric Fields
Having a net dipole moment, water molecules tend to align with an external electric field. The re-orientation of water molecules to align with the field direction can result in structural and dynamic changes in liquid water. Studying these changes can help us to understand the role of an E-field in many biological systems, chemical reactions, and many technological advancements.
In short, the application of static electric fields causes molecules to stay aligned with the field, so, fewer hydrogen bonds break, and molecules have slower dynamics. This type of field can be used when the mobility of water molecules needs to be reduced, like in electroporation. Alternating electric fields, on the other hand, cause continuous re-orientation of dipole moments, which results in more H bond breaking, water is less structured, and molecules have faster motion.
Water under static and alternating electric fields have several applications in science and technology. Although many of the interesting usages of the application of electric fields to water happen at surfaces, the response of hydrogen bonding of water molecules to an E-field is still not fully understood even in bulk. For instance, the rate of hydrogen bond breaking, the re-orientation of water molecules, and the random walk of water molecules under the restrictions of the static electric field have not been thoroughly assessed. The static electric field limits the re-orientation of water molecules, but the translation reduces at the same time, this is clear evidence of roto-translational coupling, and the static electric field is a great groundwork for studying this coupling which is generated by the hydrogen bonds.
For studying the effects of an E-field on H-bonding dynamics in depth, we need a model of hydrogen bonding. There are a few models for dynamics of H-bonding and reorientation of water molecules, including Luzar and Chandler model, published in 1996, and the Laage and Hynes jump model, published in 2006, which are described in the introduction chapter. The two models are related but have different perspectives, so it would be very interesting to look for a more general framework of hydrogen bonding by combining these two models, with the help of the influence of external electric fields. We also explain the relation of the random walk diffusion of water molecules and the hydrogen bonding.
Since the external electric field can change the dipole moment of water molecules, for a more realistic picture, we need do the simulations with sophisticated polarizable water models to obtain a better estimate of the behavior of experimental water in an electric field.
In this thesis, we introduce our generalized hydrogen bond framework; then we assess this framework, as well as other static and dynamic properties of water under static and alternating electric fields
Structure and function of mitochondria rough-er contact sites in mouse liver
La biologie des sites de contact entre organelles est une nouvelle branche de la biologie cellulaire qui étudie comment les organelles coopèrent ensemble pour coordonner des activités cellulaires complexes. Le premier contact de ce type à être décrit de manière fonctionnelle est celui qui est formé par le réticulum endoplasmique lisse (RE) et la mitochondrie, la MAM (Mitochondria-Associated ER Membrane). La MAM coordonne en effet les échanges de phospholipides et de calcium entre ces deux organelles. Cependant, on ignore si les mitochondries peuvent également former des contacts fonctionnels avec d'autres types de RE. Pour combler ce manque de connaissances, j'ai contribué, dans ma thèse, à étudier pour la première fois l'organisation morphologique et la fonction du contact entre l'ER brut et les mitochondries. Grâce à l'utilisation de la microscopie électronique (EM) et de la tomographie 3D, j'ai contribué à découvrir l'existence d'un nouveau type d'ER brut, que nous avons appelé wrappER, qui enveloppe étroitement les mitochondries dans les hépatocytes hépatiques de la souris. Sa caractérisation biochimique a révélé la présence de protéines et de transcrits impliqués dans la biogenèse des lipoprotéines de très basse densité (VLDL). De plus, mes études ont permis d'établir que la protéine Rrbp1 sert à lier les deux organelles et de découvrir que sa dérégulation dans le foie de la souris est caractérisée par une augmentation de la distance entre la mitochondrie et le wrappER ainsi qu'une diminution du taux de sécrétion des VLDL. Sur la base de ces résultats, nous avons proposé que les contacts wrappER-mitochondrie participent à l'homéostasie des lipides en régulant le taux de sécrétion des VLDL.The biology of inter-organelle contact sites is a new branch of cell biology that studies how organelles cooperate together to coordinate complex cellular activities. The first contact of this type to be functionally described was that that is formed by the smooth endoplasmic reticulum (ER) and the mitochondrion, the MAM (Mitochondria-Associated ER Membrane). The MAM indeed coordinates phospholipid and calcium exchanges between these two organelles. However, whether mitochondria can also form functionally competent contacts with other types of ER remains unknown. To fill this gap of knowledge, in my thesis I contributed to investigate for the first time the morphological organization and the function of the contact between the rough-ER and the mitochondria. Through the use of electron microscopy (EM) and 3D tomography, I have contributed to discover the existence a new type of rough-ER, which we called wrappER, that closely wraps the mitochondria in the liver hepatocytes of the mouse. Its biochemical characterization revealed the presence of proteins and transcripts involved in the biogenesis of the very low-density lipoproteins (VLDL). Furthermore, my studies have helped establish that the Rrbp1 protein serves to tether between the two organelles and discovered that its down-regulation in the mouse liver is characterized by an increase in the distance between mitochondrion and wrappER as well as to a decrease in the secretion rate of VLDL. Based on these results, we have proposed that wrappER-mitochondrion contacts participate in lipid homeostasis by regulating the rate of VLDL secretion
Job burnout and some of its risk factors on the health workers (Behvarz) in Koohrang County, I.R.Iran, in 2010
زمینه و هدف : فرسودگی شغلی، شامل خستگی عاطفی ، مسخ شخصیت و کاهش موفقیت فردی است و زمانی که توانایی های فرد برای تقاضاهای محیط کار کافی نباشد علائم آن آشکار می شود. کارکنان نظام سلامت به دلیل مواجهه با استرس های فیزیکی و روانی در معرض فرسودگی می باشند. این مطالعه با هدف تعیین میزان فرسودگی شغلی بهورزان و بررسی ارتباط خصوصیات جمعیت شناختی با آن انجام گرفت . روش بررسی: این پژوهش توصیفی-تحلیلی، بر روی همه بهورزان شهرستان کوهرنگ ( 81 نفر) در آبانماه سال 1389 انجام شد . ابزار گردآوری داده ها پرسشنامهای شامل اطلاعات جمعیت شناختی و پرسشنامه فرسودگی شغلی مازلاک ( MBI ) بود. پرسشنامه توسط بهورزان تکمیل و دادهها با استفاده از آزمون های آماری ANOVA ، ضریب همبستگی اسپیرمن و آزمون تی مستقل تحلیل گردید. یافته ها: از نظر فراوانی، کاهش موفقیت فردی زیاد ( 5/24 ) ، خستگی عاطفی زیاد ( 6/4 ) و مسخ شخصیت زیاد ( 7/2 ) ، به ترتیب از بیشترین فراوانی و از نظر شدت، خستگی عاطفی شدید ( 7/6 ) و مسخ شخصیت شدید ( 3/1 ) ، به ترتیب از بیشترین شدت برخوردار بودند. هیچ یک از بهورزان کاهش شدید موفقیت فردی را گزارش ننمود. میزان خستگی عاطفی با مسخ شخصیت و میزان کاهش موفقیت فردی با خستگی عاطفی رابطه معنی داری داشت (001/0 > P ) . بین جنس، سن، وضعیت تأهل، سابقه کار، نوع استخدام و میزان تحصیلات بهورزان و فرسودگی رابطه معنی داری دیده نشد. نتیجه گیری: این مطالعه نشان داد که فراوانی و شدت فرسودگی شغلی در بهورزان شهرستان کوهرنگ پایین است که از دلایل آن می توان به موقعیت اجتماعی مناسب، نزدیکی محل کار و زندگی، درآمد متناسب با حجم کار و تحصیلات، امنیت شغلی، سطح توقع پایین و شرایط آب و هوایی و فرهنگی منطقه اشاره کر
Wage Earner
The complex process of economic and cultural displacement that newcomers to Canada experience is examined in this Master of Fine Arts thesis. This supplementary essay begins with a study of the difficulties faced by immigrants in Canada and how these difficulties affect their professional careers. Due to these difficulties, some of these groups of people find themselves stuck in blue-collar jobs for a while, though for some it may take longer depending on a number of factors. This paper places my method of visual story telling in the context of this artistic path and positions my work within the field of contemporary photography through a discussion of some contemporary photography works, both my own and those of my contemporaries. After that, I discuss how I try to portray an accurate and sympathetic representation of the immigrant experience in my photography by using my personal experiences and background to inform my approach. Furthermore, I go into detail about how I went about creating this project, how I built relationships with my subjects, and how our experiences are shared. I also explain why I'm using text, how it can help viewers connect with the narration, and how it can help viewers understand the characters' actual lives
Source of Errors in English Headless Relative Clauses Produced by Persian Learners/Speakers of English
This paper focuses on errors made by Persian learners of English as a Foreign Language (EFL) when producing English headless relative clauses (RCs). Although English does not allow interrogative structure in headless RCs, Persian EFL learners tend to produce them in the interrogative form. In the course of the present research, potential sources of this error were explored, and eventually the Markedness Differential Hypothesis (MDH) showed to have more explanatory power, and made up the theoretical framework of the research. The oral and written corpus of the study was obtained in the course of two years through diverse sources from 137 female and male Iranian participants. The collected, naturally-occurring data yielded a pool of 126 ill-formed RCs, consisting of 85 (67.46%) ordinary headless, 25(19.84%) headed and 16 (12.69%) free headless RCs. Scrutiny into the data led to recognizing systematic errors in two main types (headless RC in subject or object position) and two subsidiary types (headless RC in subject position including copula verb) of English headless RCs. These systematic errors can be attributed to markedness differential hypothesis, not in the sense that the forms are different across the two languages, but because of the wider functionality of interrogative and declarative forms in English headless RCs, compared to Persian. This study calls for linguistic analysis of other facets of such systematic errors, more collaboration of linguists and language pedagogues to recognize and address learning problems, and studies on educational solutions for related problems
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