633 research outputs found

    Simulation model for a nomadic animal production system in Southern Iran.

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    The first motive for the determination and evaluation of an energy production system is the need to change. Such system is dynamic in nature and is influenced by many factors such as age and physiological status of individual sheep or goat, quantity and quality of available feed and environment including the management systems. Traditional pastoral resource assessments do not always account for the complex, interrelated nature of land, forage and livestock. Modeling may overcome the limitations of traditional methods by improving the understanding of complex pastoral systems, and makes fast repetitive analyses, spanning time, incorporating variability and representing more realistically complex interactions possible within the system. The estimated values of metabolisable energy for maintenance and production in this study are based on the results of two feeding systems linked together by grazing the energy intake in the Nomadic Production System (NPS) and the dynamic system modeling used to study the assessment of these complex systems. In this study, validation of model relied on the observations of Torki Ghashghaii (TG) sheep (like those in Bakkan) under pen-fed and integrated rangeland-cropland feeding systems, and was carried out mainly by studying the body weight gain of growing animals and also body weight changes of ewes due to pregnancy and lactation. After validation, the study indicated that the mean value of actual data of male and female lambs (weaners) and ewes were in close agreement with the simulated data. These results validate the generalized structure of energy utilization models of grazing sheep under production sub- systems of NPS. These results will enable the prediction of carrying capacities in any given situation under conditions similar to those in Bakkan

    The Role of Proper Use Factor Model for the Prediction of Available Forage in Rangeland in the South of Iran

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    In Iran, 80 to 90% of the livestock production is associated with rangeland but 48% of the rangeland has been classified as in poor condition (Farahpour, 2002). Available Forage (AF) is that portion of the forage production accessible for use by a specified kind or class of grazing animal. Estimates of AF by plant species, consumption by the animal, and the contribution of the forage to the animal\u27s diet must be synchronised with each other in the same time frame (Valentine, 2001). The Proper Use Factor (PUF) is the degree of utilisation of current year\u27s growth of the vegetation that, if continued, will achieve management objectives and maintain or improve the long-term productivity of the site. The objective of this study was to identify and determine the PUF of forage that cause effect the qualitative and quantitative aspects of AF in rangeland of Bakkan, south Iran

    Specific Resistance Genes in Wheat Chinese Landrace ‘Wangshuibai’ against Two Iranian Mycosphaerella Graminicola Isolates

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    Abstract Septoria tritici blotch, caused by the fungus Mycosphaerella graminicola, is currently the major foliar disease of wheat world-wide, and new sources of resistance and knowledge about the genetics of resistance are needed to improve breeding for resistance against this disease. An F10 recombinant inbred population from a cross between ‘Wangshuibai’ (Chinese landrace) and the susceptible cultivar ‘Seri82’ was tested at seedling stage under controlled greenhouse conditions. Two isolate-specific genes for resistance to Iranian M.graminicola isolates IPO08002 and IPO08003 were detected on Chromosomes 2BL and 7DS, respectively. For both genes the resistance was derived from ‘Wangshuibai’ at positions where Stb9 (on 2BL) and Stb4 (on 7DS) have been reported previously. These two genes are closely linked to microsatellite markers, which can be used for marker-assisted selection. ‘Wangshuibai’ may therefore be a valuable source of resistance to STB for wheat breeding, especially in Mediterranean environments

    Distinguishing fractional and white noise in one and two dimensions

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    We discuss the link between uncorrelated noise and Hurst exponent for one and two-dimensional interfaces. We show that long range correlations cannot be observed using one-dimensional cuts through two-dimensional self-affine surfaces whose height distributions are characterized by a Hurst exponent lower than -1/2. In this domain, fractional and white noise are not distinguishable. A method analysing the correlations in two dimensions is necessary. For Hurst exponents larger than -1/2, a crossover regime leads to a systematic over estimate of the Hurst exponent.Comment: 3 pages RevTeX, 4 Postscript figure

    Make Fitness Fun: Could Novelty Be the Key Determinant for Physical Activity Adherence?

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    The benefits of physical activity (PA) are well known and are extensively delineated in the scientific literature. Regular participation in PA, or exercise as its subset (structured, preplanned form of PA), is positively associated with numerous physical and psychological health benefits across all population subgroups (i.e., different age groups, gender, ethnicity, and socioeconomic status) (Paterson and Warburton, 2010; Warburton and Bredin, 2017). The current PA guidelines for adults, proposed by the American College for Sports Medicine and American Heart Association (ACSM/AHA), recommend the accumulation of at least 150 min of moderate intensity aerobic PA per week (Nelson et al., 2007). Additionally, it is recommended that adults should engage in muscle-strengthening activities at least two times per week (Garber et al., 2011). Despite this, sedentary behavior remains a major challenge, and insufficient PA rates have remained stable at the global level between 2001 and 2016 (Guthold et al., 2018). Physical inactivity is the fourth leading cause of death worldwide and its annual health-care costs have been estimated at 53.8 billion US dollars in 2012 internationally (Ding et al., 2016). However, it has recently been shown that with sufficient PA, as many as 3.9 million premature deaths could be averted annually (Strain et al., 2020), and thus more needs to be done to improve engagement and maintenance of PA throughout the lifespan

    Phosphopantetheinyl transferase (Ppt)-mediated biosynthesis of lysine, but not siderophores or DHN melanin, is required for virulence of Zymoseptoria tritici on wheat

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    Zymoseptoria tritici is the causal agent of Septoria tritici blotch (STB) disease of wheat. Z. tritici is an apoplastic fungal pathogen, which does not penetrate plant cells at any stage of infection, and has a long initial period of symptomless leaf colonisation. During this phase it is unclear to what extent the fungus can access host plant nutrients or communicate with plant cells. Several important primary and secondary metabolite pathways in fungi are regulated by the post-translational activator phosphopantetheinyl transferase (Ppt) which provides an essential co-factor for lysine biosynthesis and the activities of non-ribosomal peptide synthases (NRPS) and polyketide synthases (PKS). To investigate the relative importance of lysine biosynthesis, NRPS-based siderophore production and PKS-based DHN melanin biosynthesis, we generated deletion mutants of ZtPpt. The ?ZtPpt strains were auxotrophic for lysine and iron, non-melanised and non-pathogenic on wheat. Deletion of the three target genes likely affected by ZtPpt loss of function (Aar- lysine; Nrps1-siderophore and Pks1- melanin), highlighted that lysine auxotrophy was the main contributing factor for loss of virulence, with no reduction caused by loss of siderophore production or melanisation. This reveals Ppt, and the lysine biosynthesis pathway, as potential targets for fungicides effective against Z. tritici

    A simple vapor-diffusion method enables protein crystallization inside the HARE serial crystallography chip

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    Fixed-target serial crystallography has become an important method for the study of protein structure and dynamics at synchrotrons and X-ray free-electron lasers. However, sample homogeneity, consumption and the physical stress on samples remain major challenges for these high-throughput experiments, which depend on high-quality protein microcrystals. The batch crystallization procedures that are typically applied require time- and sample-intensive screening and optimization. Here, a simple protein crystallization method inside the features of the HARE serial crystallography chips is reported that circumvents batch crystallization and allows the direct transfer of canonical vapor-diffusion conditions to in-chip crystallization. Based on conventional hanging-drop vapor-diffusion experiments, the crystallization solution is distributed into the wells of the HARE chip and equilibrated against a reservoir with mother liquor. Using this simple method, high-quality microcrystals were generated with sufficient density for the structure determination of four different proteins. A new protein variant was crystallized using the protein concentrations encountered during canonical crystallization experiments, enabling structure determination from ∼55 µg of protein. Additionally, structure determination from intracellular crystals grown in insect cells cultured directly in the features of the HARE chips is demonstrated. In cellulo crystallization represents a comparatively un­explored space in crystallization, especially for proteins that are resistant to crystallization using conventional techniques, and eliminates any need for laborious protein purification. This in-chip technique avoids harvesting the sensitive crystals or any further physical handling of the crystal-containing cells. These proof-of-principle experiments indicate the potential of this method to become a simple alternative to batch crystallization approaches and also as a convenient extension to canonical crystallization screens

    Chitosan-based Nanoparticles in Mucosal Vaccine Delivery

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    Most infectious diseases are caused by pathogenic infiltrations from the mucosal tract. Nowadays, the use of vaccines has been widely investigated for the prevention of different infectious diseases, infertility, immune disorders, malignancies, and allergies. Broad-spectrum adjuvant substances have been studied for immune system stimulation with a greater efficiency against specific antigens. Various adjuvants have been developed such as inorganic, oil-based, and emulsion adjuvants, bacterial products and their derivatives, cytokines, cytosine-guanine dinucleotide (CpG) motifs, and particulate systems. Mucosal vaccine delivery is an alternative route to induce both humoral and cellular immune responses. Applying nanoparticles in vaccine formulations allows not only improved antigen stability and immunogenicity, but also targeted delivery, and consequently, more specific release of the agent of interest. Chitosan nanoparticles have immunological activity and mucoadhesive properties. They have been used as a mucosal vaccine delivery system for many antigens. This review provides an overview of the recent advances in chitosan nanoparticles as a novel mucosal vaccine delivery system

    Bovine Leukemia virus (BLV) and risk of breast cancer: A systematic review and meta-analysis of case-control studies

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    Background: Breast cancer is reported as one of the most common cancers among females worldwide. Infectious agents especially viruses have been considered as role players in the development of breast cancer. Although some investigations suggest an association between bovine leukemia virus (BLV) and breast cancer, the involvement of this virus as a risk factor remains controversial. The present study aimed to find out any possible association between BLV and breast cancer through conducting a systematic review and meta-analysis. Methods: Systematic literature search was performed by finding related case-control articles from the PubMed, Google Scholar, Web of Science, Scopus, and EMBASE databases. The heterogeneity and the multivariable-adjusted OR and corresponding 95 CI were applied by meta-analysis and forest plot across studies. All statistical analyses were performed using Stata 14.1. Result: Based on a comprehensive literature search, 9 case-control studies were included for meta-analysis. The combination of all included studies showed that BLV infection is associated with an increased risk of breast cancer summary OR (95% CI) 2.57 (1.45, 4.56). Conclusion: This is the first meta-analysis to analyze a potential association between BLV infection and the risk of breast cancer. Control of the infection in cattle herds and screening of the milk and dairy products may help to reduce the transmission of the virus to humans. © 2020 The Author(s)
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