Showing papers by "Oklahoma State University–Stillwater published in 2010"
TL;DR: A quality assessment method [most apparent distortion (MAD)], which attempts to explicitly model these two separate strategies, local luminance and contrast masking and changes in the local statistics of spatial-frequency components are used to estimate appearance-based perceived distortion in low-quality images.
Abstract: The mainstream approach to image quality assessment has centered around accurately modeling the single most relevant strategy employed by the human visual system (HVS) when judging image quality (e.g., detecting visible differences, and extracting image structure/information). In this work, we suggest that a single strategy may not be sufficient; rather, we advocate that the HVS uses multiple strategies to determine image quality. For images containing near-threshold distortions, the image is most apparent, and thus the HVS attempts to look past the image and look for the distortions (a detection-based strategy). For images containing clearly visible distortions, the distortions are most apparent, and thus the HVS attempts to look past the distortion and look for the image's subject matter (an appearance-based strategy). Here, we present a quality assessment method [most apparent distortion (MAD)], which attempts to explicitly model these two separate strategies. Local luminance and contrast masking are used to estimate detection-based perceived distortion in high-quality images, whereas changes in the local statistics of spatial-frequency components are used to estimate appearance-based perceived distortion in low-quality images. We show that a combination of these two measures can perform well in predicting subjective ratings of image quality.
1,651 citations
TL;DR: This review focuses on energy storage and release in insects and summarizes current understanding of the mechanisms underlying these processes in insects.
Abstract: The fat body plays major roles in the life of insects. It is a dynamic tissue involved in multiple metabolic functions. One of these functions is to store and release energy in response to the energy demands of the insect. Insects store energy reserves in the form of glycogen and triglycerides in the adipocytes, the main fat body cell. Insect adipocytes can store a great amount of lipid reserves as cytoplasmic lipid droplets. Lipid metabolism is essential for growth and reproduction and provides energy needed during extended nonfeeding periods. This review focuses on energy storage and release and summarizes current understanding of the mechanisms underlying these processes in insects.
1,617 citations
TL;DR: In this paper, the authors examined the business case for the inclusion of women and ethnic minority directors on the board and found no significant relationship between the gender or ethnic diversity of the board, or important board committees, and financial performance for a sample of major US corporations.
Abstract: Manuscript Type: Empirical Research Question/Issue: We examine the business case for the inclusion of women and ethnic minority directors on the board. Specifically, we investigate the relationship between the number of women directors and the number of ethnic minority directors on the board and important board committees and financial performance measured as return on assets and Tobin’s Q. Research Findings/Insights: We do not find a significant relationship between the gender or ethnic diversity of the board, or important board committees, and financial performance for a sample of major US corporations. Our evidence also suggests that the gender and ethnic minority diversity of the board and firm financial performance appear to be endogenous. Theoretical/Academic Implications: Reasonable theoretical arguments drawn from resource dependence theory, human capital theory, agency theory, and social psychology suggest that gender and ethnic diversity may have either a positive, negative, or neutral effect on the financial performance of the firm. Our statistical analysis supports the theoretical position of no effect, either positive or negative. Our results are consistent with a contingency explanation because the effect of the gender and ethnic diversity of the board may be different under different circumstances at different times. Over several companies and time periods, the results could offset to produce no effect. Practitioner/Policy Implications: The results of our analysis do not support the business case for inclusion of women and ethnic minorities on corporate boards. However, we find no evidence of any negative effect either. Our evidence implies that decisions concerning the appointment of women and ethnic minorities to corporate boards should be based on criteria other than future financial performance.
1,297 citations
TL;DR: Univariate analyses supported the hypothesis that plant response is most positive when plants are P-limited rather than N-limited when the soil community was more complex, and emphasize that mycorrhizal function depends on both abiotic and biotic context.
Abstract: Ecology Letters (2010) 13: 394-407 Abstract Mycorrhizal fungi influence plant growth, local biodiversity and ecosystem function. Effects of the symbiosis on plants span the continuum from mutualism to parasitism. We sought to understand this variation in symbiotic function using meta-analysis with information theory-based model selection to assess the relative importance of factors in five categories: (1) identity of the host plant and its functional characteristics, (2) identity and type of mycorrhizal fungi (arbuscular mycorrhizal vs. ectomycorrhizal), (3) soil fertility, (4) biotic complexity of the soil and (5) experimental location (laboratory vs. field). Across most subsets of the data, host plant functional group and N-fertilization were surprisingly much more important in predicting plant responses to mycorrhizal inoculation ('plant response') than other factors. Non-N-fixing forbs and woody plants and C(4) grasses responded more positively to mycorrhizal inoculation than plants with N-fixing bacterial symbionts and C(3) grasses. In laboratory studies of the arbuscular mycorrhizal symbiosis, plant response was more positive when the soil community was more complex. Univariate analyses supported the hypothesis that plant response is most positive when plants are P-limited rather than N-limited. These results emphasize that mycorrhizal function depends on both abiotic and biotic context, and have implications for plant community theory and restoration ecology.
910 citations
TL;DR: In this article, the authors draw on the original job characteristics model (JCM) and on an elaborated model of work design to examine relationships between ethical leadership, task significance, job autonomy, effort, and job performance.
Abstract: Summary In the current study, we draw on the original job characteristics model (JCM) and on an elaborated model of work design to examine relationships between ethical leadership, task significance, job autonomy, effort, and job performance. We suggest that leaders with strong ethical commitments who regularly demonstrate ethically normative behavior can have an impacton the JCM elementsof tasksignificance and autonomy, thereby affecting anemployee’s motivation (willingness to exert effort), which in turn will be evidenced by indications of enhanced task performance and organizational citizenship behavior. We conducted a field study by surveying pairs of co-workers in a diverse set of organizations. Results provide support for a fully mediated model whereby task significance and effort fully mediate relationships between ethical leadership and subordinates’ job performance. Implications for future research on job design are discussed. Copyright # 2010 John Wiley & Sons, Ltd. At the heart of the job characteristics model (JCM, Hackman & Oldham, 1976) is the premise that leaders canshape intrinsic motivation bytheway inwhich theystructuretheobjectivecharacteristics of the work itself. 1 The theoretical model of job design was rooted in an examination of the ‘‘basic conditions that promote high performance motivation and satisfaction at work,’’ in order ‘‘to determine how those conditions can be created’’ (Hackman & Oldham, 1976; p. 71). We argue that the conceptual and empirical developments of the JCM to date can be expanded to encompass a broader role for leaders. In particular, we suggest that leaders with strong ethical commitments who regularly demonstrate ethically normative behavior can have an impact on the JCM elements of task significance and autonomy, thereby affecting an employee’s motivation (willingness to exert effort), which in turn will be evidenced by indications of enhanced task performance and organizational citizenship behaviors.
655 citations
TL;DR: In this paper, the authors consider the dynamical behavior of a nanomechanical mirror in a high-quality cavity under the action of a coupling laser and a probe laser and demonstrate the existence of the analog of electromagnetically induced transparency (EIT) in the output field at the probe frequency.
Abstract: We consider the dynamical behavior of a nanomechanical mirror in a high-quality cavity under the action of a coupling laser and a probe laser. We demonstrate the existence of the analog of electromagnetically induced transparency (EIT) in the output field at the probe frequency. Our calculations show explicitly the origin of EIT-like dips as well as the characteristic changes in dispersion from anomalous to normal in the range where EIT dips occur. Remarkably the pump-probe response for the optomechanical system shares all the features of the $\ensuremath{\Lambda}$ system as discovered by Harris and collaborators.
644 citations
TL;DR: In this article, the authors used the ATLAS detector to detect dijet asymmetry in the collisions of lead ions at the Large Hadron Collider and found that the transverse energies of dijets in opposite hemispheres become systematically more unbalanced with increasing event centrality, leading to a large number of events which contain highly asymmetric di jets.
Abstract: By using the ATLAS detector, observations have been made of a centrality-dependent dijet asymmetry in the collisions of lead ions at the Large Hadron Collider. In a sample of lead-lead events with a per-nucleon center of mass energy of 2.76 TeV, selected with a minimum bias trigger, jets are reconstructed in fine-grained, longitudinally segmented electromagnetic and hadronic calorimeters. The transverse energies of dijets in opposite hemispheres are observed to become systematically more unbalanced with increasing event centrality leading to a large number of events which contain highly asymmetric dijets. This is the first observation of an enhancement of events with such large dijet asymmetries, not observed in proton-proton collisions, which may point to an interpretation in terms of strong jet energy loss in a hot, dense medium.
630 citations
TL;DR: It is hypothesized that patterns of community similarity and evolution might explain the variation in novelty advantage that can underlie variation in invasion outcomes, including suggestions for managing invasive predators, predator reintroductions and biological control.
Abstract: We present a framework for explaining variation in predator invasion success and predator impacts on native prey that integrates information about predator–prey naivete, predator and prey behavioral responses to each other, consumptive and non-consumptive eff ects of predators on prey, and interacting eff ects of multiple species interactions. We begin with the ‘naive prey’ hypothesis that posits that naive, native prey that lack evolutionary history with non-native predators suff er heavy predation because they exhibit ineff ective antipredator responses to novel predators. Not all naive prey, however, show ineff ective antipredator responses to novel predators. To explain variation in prey response to novel predators, we focus on the interaction between prey use of general versus specifi c cues and responses, and the functional similarity of non-native and native predators. Eff ective antipredator responses reduce predation rates (reduce consumptive eff ects of predators, CEs), but often also carry costs that result in non-consumptive eff ects (NCEs) of predators. We contrast expected CEs versus NCEs for non-native versus native predators, and discuss how diff erences in the relative magnitudes of CEs and NCEs might infl uence invasion dynamics. Going beyond the eff ects of naive prey, we discuss how the ‘naive prey’, ‘enemy release’ and ‘evolution of increased competitive ability’ (EICA) hypotheses are inter-related, and how the importance of all three might be mediated by prey and predator naivete. Th ese ideas hinge on the notion that non-native predators enjoy a ‘novelty advantage’ associated with the naivete of native prey and top predators. However, non-native predators could instead suff er from a novelty disadvantage because they are also naive to their new prey and potential predators. We hypothesize that patterns of community similarity and evolution might explain the variation in novelty advantage that can underlie variation in invasion outcomes. Finally, we discuss management implications of our framework, including suggestions for managing invasive predators, predator reintroductions and biological control.
595 citations
TL;DR: Results indicate that Andropogon ecotypes adapt to their local soil and indigenous AM fungal communities such that mycorrhizal exchange of the most limiting resource is maximized.
Abstract: Symbioses may be important mechanisms of plant adaptation to their environment. We conducted a reciprocal inoculation experiment to test the hypothesis that soil fertility is a key driver of local adaptation in arbuscular mycorrhizal (AM) symbioses. Ecotypes of Andropogon gerardii from phosphorus-limited and nitrogen-limited grasslands were grown with all possible “home and away” combinations of soils and AM fungal communities. Our results indicate that Andropogon ecotypes adapt to their local soil and indigenous AM fungal communities such that mycorrhizal exchange of the most limiting resource is maximized. Grasses grown in home soil and inoculated with home AM fungi produced more arbuscules (symbiotic exchange structures) in their roots than those grown in away combinations. Also, regardless of the host ecotype, AM fungi produced more extraradical hyphae in their home soil, and locally adapted AM fungi were, therefore, able to sequester more carbon compared with nonlocal fungi. Locally adapted mycorrhizal associations were more mutualistic in the two phosphorus-limited sites and less parasitic at the nitrogen-limited site compared with novel combinations of plants, fungi, and soils. To our knowledge, these findings provide the strongest evidence to date that resource availability generates evolved geographic structure in symbioses among plants and soil organisms. Thus, edaphic origin of AM fungi should be considered when managing for their benefits in agriculture, ecosystem restoration, and soil-carbon sequestration.
579 citations
TL;DR: A broader picture of the rumen microbial population structure during adaptation to a high-grain diet from a forage diet is presented and it is shown that the Butyrivibrio fibrisolvens and Fibrobacter succinogenes populations gradually decreased as the animals were adapted to the high-concentrate diet.
Abstract: High-grain adaptation programs are widely used with feedlot cattle to balance enhanced growth performance against the risk of acidosis. This adaptation to a high-grain diet from a high-forage diet is known to change the rumen microbial population structure and help establish a stable microbial population within the rumen. Therefore, to evaluate bacterial population dynamics during adaptation to a high-grain diet, 4 ruminally cannulated beef steers were adapted to a high-grain diet using a step-up diet regimen containing grain and hay at ratios of 20:80, 40:60, 60:40, and 80:20. The rumen bacterial populations were evaluated at each stage of the step-up diet after 1 week of adaptation, before the steers were transitioned to the next stage of the diet, using terminal restriction fragment length polymorphism (T-RFLP) analysis, 16S rRNA gene libraries, and quantitative real-time PCR. The T-RFLP analysis displayed a shift in the rumen microbial population structure during the final two stages of the step-up diet. The 16S rRNA gene libraries demonstrated two distinct rumen microbial populations in hay-fed and high-grain-fed animals and detected only 24 common operational taxonomic units out of 398 and 315, respectively. The 16S rRNA gene libraries of hay-fed animals contained a significantly higher number of bacteria belonging to the phylum Fibrobacteres, whereas the 16S rRNA gene libraries of grain-fed animals contained a significantly higher number of bacteria belonging to the phylum Bacteroidetes. Real-time PCR analysis detected significant fold increases in the Megasphaera elsdenii, Streptococcus bovis, Selenomonas ruminantium, and Prevotella bryantii populations during adaptation to the high-concentrate (high-grain) diet, whereas the Butyrivibrio fibrisolvens and Fibrobacter succinogenes populations gradually decreased as the animals were adapted to the high-concentrate diet. This study evaluates the rumen microbial population using several molecular approaches and presents a broader picture of the rumen microbial population structure during adaptation to a high-grain diet from a forage diet.
552 citations
TL;DR: A review of seminal literature on the use of continuous EEG to measure cognitive load is presented in this article, where the authors describe two case studies on learning from hypertext and multimedia that employed EEG methodology to collect and analyze cognitive load data.
Abstract: Application of physiological methods, in particular electroencephalography (EEG), offers new and promising approaches to educational psychology research. EEG is identified as a physiological index that can serve as an online, continuous measure of cognitive load detecting subtle fluctuations in instantaneous load, which can help explain effects of instructional interventions when measures of overall cognitive load fail to reflect such differences in cognitive processing. This paper presents a review of seminal literature on the use of continuous EEG to measure cognitive load and describes two case studies on learning from hypertext and multimedia that employed EEG methodology to collect and analyze cognitive load data.
TL;DR: The authors examine the conservative movement's efforts to undermine climate science and policy in the USA over the last two decades by using this second dimension of power, and argue that reflexive modernization scholars should focus more attention on similar forces of anti-reflexivity that continue to shape the overall direction of our social, political and economic order, and the life chances of many citizens.
Abstract: The American conservative movement is a force of anti-reflexivity insofar as it attacks two key elements of reflexive modernization: the environmental movement and environmental impact science. Learning from its mistakes in overtly attacking environmental regulations in the early 1980s, this countermovement has subsequently exercised a more subtle form of power characterized by non-decision-making. We examine the conservative movement’s efforts to undermine climate science and policy in the USA over the last two decades by using this second dimension of power. The conservative movement has employed four non-decision-making techniques to challenge the legitimacy of climate science and prevent progress in policy-making. We argue that reflexive modernization scholars should focus more attention on similar forces of anti-reflexivity that continue to shape the overall direction of our social, political and economic order, and the life chances of many citizens. Indeed, better understanding of the forces and effectiveness of anti-reflexivity may very well be crucial for societal resilience and adaptation, especially in the face of global environmental problems like climate change.
TL;DR: This paper examined the relationship between ethical leadership and employee misconduct using a sample of 1,525 employees and their supervisors in 300 units in different organizations, and found support for their hypothesized model.
Abstract: Drawing on theory and research on ethical leadership and ethical climate, we examine ethical climate as a mediator of the relationship between ethical leadership and employee misconduct. Using a sample of 1,525 employees and their supervisors in 300 units in different organizations, we find support for our hypothesized model. We discuss theoretical and practical implications of these findings.
TL;DR: This study shows blueberries may improve selected features of metabolic syndrome and related cardiovascular risk factors at dietary achievable doses in obese men and women.
Abstract: Among all fruits, berries have shown substantial cardio-protective benefits due to their high polyphenol content. However, investigation of their efficacy in improving features of metabolic syndrome and related cardiovascular risk factors in obesity is limited. We examined the effects of blueberry supplementation on features of metabolic syndrome, lipid peroxidation, and inflammation in obese men and women. Forty-eight participants with metabolic syndrome [4 males and 44 females; BMI: 37.8 ± 2.3 kg/m2; age: 50.0 ± 3.0 y (mean ± SE)] consumed freeze-dried blueberry beverage (50 g freeze-dried blueberries, #126 350 g fresh blueberries) or equivalent amounts of fluids (controls, 960 mL water) daily for 8 wk in a randomized controlled trial. Anthropometric and blood pressure measurements, assessment of dietary intakes, and fasting blood draws were conducted at screening and at wk 4 and 8 of the study. The decreases in systolic and diastolic blood pressures were greater in the blueberry-supplemented group (− 6 and − 4%, respectively) than in controls (− 1.5 and − 1.2%) (P lt 0.05), whereas the serum glucose concentration and lipid profiles were not affected. The decreases in plasma oxidized LDL and serum malondialdehyde and hydroxynonenal concentrations were greater in the blueberry group (− 28 and − 17%, respectively) than in the control group (− 9 and − 9%) (P lt 0.01). Our study shows blueberries may improve selected features of metabolic syndrome and related cardiovascular risk factors at dietary achievable doses.
TL;DR: The importance of continuing to expand and refine the detailed knowledge of Arabidopsis while seeking to appreciate the remarkable diversity that characterizes the plant kingdom is underscored.
Abstract: Twenty-five years ago, Arabidopsis thaliana emerged as the model organism of choice for research in plant biology. A consensus was reached about the need to focus on a single organism to integrate the classical disciplines of plant science with the expanding fields of genetics and molecular biology. Ten years after publication of its genome sequence, Arabidopsis remains the standard reference plant for all of biology. We reflect here on the major advances and shared resources that led to the extraordinary growth of the Arabidopsis research community. We also underscore the importance of continuing to expand and refine our detailed knowledge of Arabidopsis while seeking to appreciate the remarkable diversity that characterizes the plant kingdom.
TL;DR: Advances in genomics, proteomics, immunology and biochemical and molecular technologies during the last decade have been applied to research on A. marginale and related organisms, and the recent development of a cell culture system for A.marginale has provided a format for studying the pathogen/tick interface.
TL;DR: In this article, the authors integrate entrepreneurship, institutional, and network theories to discuss how the entrepreneurship process of MNEs is negatively affected in base of the pyramid markets, and explain how partnerships with nongovernment organizations (NGOs) can offset such negative effects.
Abstract: Although base of the pyramid markets are significant sources of entrepreneurial opportunities, the nature of entrepreneurship in these markets is not well understood. Additionally, these markets remain largely underserved by multinational enterprises (MNEs). Given theoretical and practical gaps associated with these issues, we integrate entrepreneurship, institutional, and network theories to discuss how the entrepreneurship process of MNEs is negatively affected in base of the pyramid markets. We then explain how partnerships with nongovernment organizations (NGOs) can offset such negative effects due to NGOs' high degree of localized knowledge, social embeddedness within multiple informal networks, and ambidexterity in dealing with diverse stakeholder groups. Both economic and social benefits can result from such partnerships.
Journal Article•
TL;DR: A multi-trait selection programme in which improving health, fertility and other welfare traits are included in the breeding objective, and appropriately weighted relative to production traits, should be adopted by all breeding organisations motivated in their goal of improving welfare.
Abstract: Milk yield per cow has more than doubled in the previous 40 years and many cows now produce more than 20,000 kg of milk per lactation. The increase in production should be viewed with concern because: i) the increase in milk yield has been accompanied by declining fertility, increasing leg and metabolic problems and declining longevity; ii) there are unfavourable genetic correlations between milk yield and fertility, mastitis and other production diseases, indicating that deterioration in fertility and health is largely a consequence of selection for increased milk yield; and iii) high disease incidence, reduced fertility, decreased longevity and modification of normal behaviour are indicative of substantial decline in cow welfare. Improving welfare is important as good welfare is regarded by the public as indicative of sustainable systems and good product quality and may also be economically beneficial. Expansion of the Profitable Lifetime Index used in the UK to include mastitis resistance and fertility could increase economic response to selection by up to 80%, compared with selection for milk production alone. In the last 10 years, several breeding organisations in Europe and North America followed the example of Nordic Countries and have included improving fertility and reducing incidence of mastitis in their breeding objectives, but these efforts are still timid. A multi-trait selection programme in which improving health, fertility and other welfare traits are included in the breeding objective, and appropriately weighted relative to production traits, should be adopted by all breeding organisations motivated in their goal of improving welfare.
TL;DR: Data support the recommendation of berries as an essential fruit group in a heart-healthy diet and underlying mechanisms are believed to include upregulation of endothelial nitric oxide synthase, decreased activities of carbohydrate digestive enzymes, decreased oxidative stress, and inhibition of inflammatory gene expression and foam cell formation.
Abstract: Berries are a good source of polyphenols, especially anthocyanins, micronutrients, and fiber. In epidemiological and clinical studies, these constituents have been associated with improved cardiovascular risk profiles. Human intervention studies using chokeberries, cranberries, blueberries, and strawberries (either fresh, or as juice, or freeze-dried), or purified anthocyanin extracts have demonstrated significant improvements in LDL oxidation, lipid peroxidation, total plasma antioxidant capacity, dyslipidemia, and glucose metabolism. Benefits were seen in healthy subjects and in those with existing metabolic risk factors. Underlying mechanisms for these beneficial effects are believed to include upregulation of endothelial nitric oxide synthase, decreased activities of carbohydrate digestive enzymes, decreased oxidative stress, and inhibition of inflammatory gene expression and foam cell formation. Though limited, these data support the recommendation of berries as an essential fruit group in a heart-healthy diet.
TL;DR: In this paper, the authors applied the degradome sequencing approach to identify small RNA targets in rice, which globally identifies the remnants of small RNA-directed target cleavage by sequencing the 5' ends of uncapped RNAs.
Abstract: MicroRNA (miRNA)-guided target RNA expression is vital for a wide variety of biological processes in eukaryotes. Currently, miRBase (version 13) lists 142 and 353 miRNAs from Arabidopsis and rice (Oryza sativa), respectively. The integration of miRNAs in diverse biological networks relies upon the confirmation of their RNA targets. In contrast with the well-characterized miRNA targets that are cleaved in Arabidopsis, only a few such targets have been confirmed in rice. To identify small RNA targets in rice, we applied the 'degradome sequencing' approach, which globally identifies the remnants of small RNA-directed target cleavage by sequencing the 5' ends of uncapped RNAs. One hundred and sixty targets of 53 miRNA families (24 conserved and 29 rice-specific) and five targets of TAS3-small interfering RNAs (siRNAs) were identified. Surprisingly, an additional conserved target for miR398, which has not been reported so far, has been validated. Besides conserved homologous transcripts, 23 non-conserved genes for nine conserved miRNAs and 56 genes for 29 rice-specific miRNAs were also identified as targets. Besides miRNA targets, the rice degradome contained fragments derived from MIRNA precursors. A closer inspection of these fragments revealed a unique pattern distinct from siRNA-producing loci. This attribute can serve as one of the ancillary criteria for separating miRNAs from siRNAs in plants.
TL;DR: Transgenic analysis in different plant species revealed that cold tolerance can be significantly enhanced by genetic engineering CBF pathway, and cold stress-regulated miRNAs have been identified in Arabidopsis and rice.
Abstract: Cold stress adversely affects plant growth and development and thus limits crop productivity. Diverse plant species tolerate cold stress to a varying degree, which depends on reprogramming gene expression to modify their physiology, metabolism, and growth. Cold signal in plants is transmitted to activate CBF-dependent (C-repeat/drought-responsive element binding factor-dependent) and CBF-independent transcriptional pathway, of which CBF-dependent pathway activates CBF regulon. CBF transcription factor genes are induced by the constitutively expressed ICE1 (inducer of CBF expression 1) by binding to the CBF promoter. ICE1-CBF cold response pathway is conserved in diverse plant species. Transgenic analysis in different plant species revealed that cold tolerance can be significantly enhanced by genetic engineering CBF pathway. Posttranscriptional regulation at pre-mRNA processing and export from nucleus plays a role in cold acclimation. Small noncoding RNAs, namely micro-RNAs (miRNAs) and small interfering RNAs (siRNAs), are emerging as key players of posttranscriptional gene silencing. Cold stress-regulated miRNAs have been identified in Arabidopsis and rice. In this chapter, recent advances on cold stress signaling and tolerance are highlighted.
TL;DR: Methods for determining total ROS and lipid peroxidation assay, histochemical staining techniques for superoxide and H( 2)O(2) molecules are described.
Abstract: Reactive oxygen species or intermediates are formed by the incomplete reduction of oxygen. Organisms living in aerobic environment generate various kinds of reactive oxygen species (ROS) molecules, such as superoxide (*O(2)(-)), hydrogen peroxide (H(2)O(2)), hydroxyl radical (OH(-)), singlet oxygen, and lipid hydroperoxides. ROS are highly reactive molecules and are extremely unstable, so detection of ROS relies on measuring the end products that are formed when they react with particular substances. The end products can be measured by changes in their fluorescence, color, or luminescence. ROS causes lipid peroxidation wherein the lipids in the cell membranes are damaged. Lipid peroxidation is usually quantified using a colorimetric assay. When ROS concentrations reach a certain threshold, it activates a programmed cell death response in the cells. This is quantified by measuring the amount of ion leakage. ROS such as superoxide and hydrogen peroxide have been detected traditionally by staining techniques. Superoxide anion is detected with nitroblue tetrazolium (NBT) and hydrogen peroxide by Diaminobenzidine tetrahydrochloride (DAB) staining. In this chapter, methods for determining total ROS and lipid peroxidation assay, histochemical staining techniques for superoxide and H(2)O(2) molecules are described.
TL;DR: This paper investigated the effects of preschool patterns of parental authority on adolescent competence and emotional health and differentiated between confrontive and coercive power-assertive practices which accounted partially for differential long-term effects of the preschool patterns.
Abstract: SYNOPSIS Objective . The authors investigated the effects of preschool patterns of parental authority on adolescent competence and emotional health and differentiated between confrontive and coercive power-assertive practices which accounted partially for differential long-term effects of the preschool patterns. Design . Participants were 87 families initially studied when children were preschool students, with outcomes assessed during early adolescence. Families were drawn from Baumrind's Family Socialization and Developmental Competence longitudinal program of research. The authors used comprehensive observational and interview data to test hypotheses relating preschool power-assertive practices and patterns of parental authority to the children's attributes as adolescents. Person-centered analyses contrasted adolescent attributes associated with 7 preschool patterns of parental authority. The authors used variable-centered analyses to investigate the differential effects of 5 coercive power-assertive p...
Journal Article•
TL;DR: The complexity of BRD has made it difficult to define involvement of individual factors, and stressors may play a role as "necessary but not sufficient" components, requiring additive effects to cause disease.
Abstract: Bovine respiratory disease (BRD) is the most costly disease of beef cattle in North America. It is multi-factorial, with a variety of physical and physiological stressors combining to predispose cattle to pneumonia. However, efforts to discern which factors are most important have frequently failed to establish definitive answers. Calves are at highest risk shortly after transport. Risk factors include purchasing from sale barns and commingling. It is unclear whether or not these practices increase susceptibility, increase exposure, or are proxies for poor management. Lighter-weight calves appear to be at greater risk, although this has not been consistent. Persistent infection (PI) with bovine virus diarrhea virus increases BRD occurrence, but it is unclear if PI calves affect other cattle in the feedlot. The complexity of BRD has made it difficult to define involvement of individual factors. Stressors may play a role as “necessary but not sufficient” components, requiring additive effects to cause disease.
TL;DR: In this paper, the authors investigate the literature on organic and local foods over the past few decades and find that demand for local food arose largely in response to corporate co-optation of the organic food market and the arrival of "organic lite".
Abstract: Demand for local food in the US has significantly increased over the past decade. In an attempt to understand the drivers of this demand and how they have changed over time, we investigate the literature on organic and local foods over the past few decades. We focus our review on studies that allow comparison of characteristics now associated with both local and organic food. We summarize the major findings of these studies and their implications for understanding drivers of local food demand. Prior to the late 1990s, most studies failed to consider factors now associated with local food, and the few that included these factors found very little support for them. In many cases, the lines between local and organic were blurred. Coincident with the development of federal organic food standards, studies began to find comparatively more support for local food as distinct and separate from organic food. Our review uncovers a distinct turn in the demand for local and organic food. Before the federal organic standards, organic food was linked to small farms, animal welfare, deep sustainability, community support and many other factors that are not associated with most organic foods today. Based on our review, we argue that demand for local food arose largely in response to corporate co-optation of the organic food market and the arrival of ‘organic lite’. This important shift in consumer preferences away from organic and toward local food has broad implications for the environment and society. If these patterns of consumer preferences prove to be sustainable, producers, activists and others should be aware of the implications that these trends have for the food system at large.
TL;DR: Recently discovered 21-24 nt small RNAs (microRNAs [miRNAs] and small-interfering RNAs [siRNAs]), which regulate gene expression at the post-transcriptional level, are also modulated during stress and possibly contribute to the stress-induced changes in profiles of mRNAs or proteins.
TL;DR: A model suggesting that customers' prosocial behavior and expectations of private rewards will shape contributions to the community will shape a contribution to the company will be proposed.
Abstract: In recent years, many companies have established virtual customer environments (VCEs) that offer facilities ranging from online discussion forums to virtual product design centers to partner with their customers in product development and product support activities. In this study, we focus on one form of VCE, online customer forums, and propose that the relevance of four distinct theoretical perspectives---social capital theory, social exchange theory, involvement, and social identity theory---to explaining customer participation will be contingent on the nature of the customer contribution context, that is, whether the contributions are to the customer community (through product support) or to the company (through product ideation). We propose a model suggesting that customers' prosocial behavior and expectations of private rewards will shape contributions to the community, whereas their perceived innovation partnership with the company and expectations of private rewards will shape a contribution to the company. We also contend that these effects will be moderated by customers' identification with the community and with the company. Our empirical findings offer support for the model and indicate that online customer forums (and more broadly VCEs) should be tailored to fit the nature of customer contribution sought. Implications for research and practice in customer co-innovation, online peer-to-peer communities, and customer relationship management are discussed.
TL;DR: New developments in lepidopteran functional genomics should lead to much more complete understanding of the immune systems of this insect group, particularly for cell biology of hemocytes and biochemical analyses of plasma proteins.
Abstract: Lepidopteran insects provide important model systems for innate immunity of insects, particularly for cell biology of hemocytes and biochemical analyses of plasma proteins. Caterpillars are also among the most serious agricultural pests, and understanding of their immune systems has potential practical significance. An early response to infection in lepidopteran larvae is the activation of hemocyte adhesion, leading to phagocytosis, nodule formation, or encapsulation. Plasmatocytes and granular cells are the hemocyte types involved in these responses. Infectious microorganisms are recognized by binding of hemolymph plasma proteins to microbial surface components. This "pattern recognition" triggers phagocytosis and nodule formation, activation of prophenoloxidase and melanization and the synthesis of antimicrobial proteins that are secreted into the hemolymph. Many hemolymph proteins that function in such innate immune responses of insects were first discovered in lepidopterans. Microbial proteinases and nucleic acids released from lysed host cells may also activate lepidopteran immune responses. Hemolymph antimicrobial peptides and proteins can reach high concentrations and may have activity against a broad spectrum of microorganisms, contributing significantly to clearing of infections. Serine proteinase cascade pathways triggered by microbial components interacting with pattern recognition proteins stimulate activation of the cytokine Spatzle, which initiates the Toll pathway for expression of antimicrobial peptides. A proteinase cascade also results inproteolytic activation of phenoloxidase and production of melanin coatings that trap and kill parasites and pathogens. The proteinases in hemolymph are regulated by specific inhibitors, including members of the serpin superfamily. New developments in lepidopteran functional genomics should lead to much more complete understanding of the immune systems of this insect group.
TL;DR: In this article, the authors established regularity criteria for the 3D incompressible MHD equations in terms of the derivative of the velocity field in one direction and the boundedness of the pressure in another direction.
TL;DR: With a better understanding of the structural determinants of HDPs for their membrane-lytic activities, it is expected that novel HDP-based antimicrobials with minimum toxicity to eukaryotic cells can be developed for resistant infections, which have become a global public health crisis.