671 research outputs found

    Intentions, Information, and Convenience: An Empirical Analysis of their Effect on the American Diet and Demand for Meat

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    The purpose of this paper will be to develop and present a new approach for examining the demand for meat by incorporating many of the advances in behavioral economics. By providing a closer approximation to how consumers actually behave, doing so should improve upon existing models. Incorporating findings from behavioral studies will also provide a richer theoretical basis to correct for the longstanding problem of endogeniety in cross-sectional studies. The theoretical model in this study begins with the Becker household production model, where individuals are assumed to maximize utility, subject to their production functions, budget constraint and time constraint. To develop a model that more accurately depicts how individual's make their food choices, this model additionally assumes that individuals 1) use household time to create food, health and relaxation; 2) make their food and nutrient consumption choices on a per-meal basis; 3) are affected by the prospect of immediate gratification, convenience and time delay, and 4) are more affected by these factors as their hunger increases.Meat Demand, Behavioral Economics, Information and Nutrition, Demand and Price Analysis,

    Functional and differential proteomic analyses to identify platelet derived factors affecting ex vivo expansion of mesenchymal stromal cells

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    Background: Multilineage differentiation, immunomodulation and secretion of trophic factors render mesenchymal stromal cells (MSC) highly attractive for clinical application. Human platelet derivatives such as pooled human platelet lysate (pHPL) and thrombin-activated platelet releasate in plasma (tPRP) have been introduced as alternatives to fetal bovine serum (FBS) to achieve GMP-compliance. However, whereas both pHPL and tPRP support similar proliferation kinetics of lipoaspirate-derived MSC (LA-MSC), only pHPL significantly accelerates bone marrow-derived MSC (BM-MSC) expansion. To identify functionally bioactive factors affecting ex vivo MSC expansion, a differential proteomic approach was performed and identified candidate proteins were evaluated within a bioassay. Results: Two dimensional difference gel electrophoresis (2D-DIGE), MALDI-TOF analyses and complementary Western blotting revealed 20 differential protein species. 14 candidate proteins occured at higher concentrations in pHPL compared to tPRP and 6 at higher concentrations in tPRP. The candidate proteins fibrinogen and apolipoprotein A1 differentially affected LA- and BM-MSC proliferation. In a second set of experiments, reference cytokines known to foster proliferation in FBS were tested for their effects in the human supplements. Interestingly although these cytokines promoted proliferation in FBS, they failed to do so when added to the humanized system. Conclusions: The differential proteomic approach identified novel platelet derived factors differentially acting on human MSC proliferation. Complementary testing of reference cytokines revealed a lack of stimulation in the human supplements compared to FBS. The data describe a new coherent approach to combine proteomic technologies with functional testing to develop novel, humanized, GMP-compliant conditions for MSC expansion

    Detecting transient gravitational waves in non-Gaussian noise with partially redundant analysis methods

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    There is a broad class of astrophysical sources that produce detectable, transient, gravitational waves. Some searches for transient gravitational waves are tailored to known features of these sources. Other searches make few assumptions about the sources. Typically events are observable with multiple search techniques. This work describes how to combine the results of searches that are not independent, treating each search as a classifier for a given event. This will be shown to improve the overall sensitivity to gravitational-wave events while directly addressing the problem of consistent interpretation of multiple trials.Comment: 11 pages, 5 figure

    Likelihood-ratio ranking of gravitational-wave candidates in a non-Gaussian background

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    We describe a general approach to detection of transient gravitational-wave signals in the presence of non-Gaussian background noise. We prove that under quite general conditions, the ratio of the likelihood of observed data to contain a signal to the likelihood of it being a noise fluctuation provides optimal ranking for the candidate events found in an experiment. The likelihood-ratio ranking allows us to combine different kinds of data into a single analysis. We apply the general framework to the problem of unifying the results of independent experiments and the problem of accounting for non-Gaussian artifacts in the searches for gravitational waves from compact binary coalescence in LIGO data. We show analytically and confirm through simulations that in both cases the likelihood ratio statistic results in an improved analysis.Comment: 10 pages, 6 figure

    DDoS Defense using MTD and SDN

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    Distributed large-scale cyber attacks targeting the availability of computing and network resources still remains a serious threat. In order to limit the effects caused by those attacks and to provide a proactive defense, mitigation should move to the networks of Internet Service Providers. In this context, Moving Target Defense (MTD) is a technique that increases uncertainty due to an ever-changing attack surface. In combination with Software Defined Networking (SDN), MTD has the potential to reduce the effects of a large-scale cyber attack. In this paper, we combine the defense techniques moving- target using Software Defined Networking and investigate their effectiveness. We review current moving-target defense strategies and their applicability in context of large-scale cyber attacks and the networks of Internet Service Providers. Further, we enforce the implementation of moving target defense strategies using Software Defined Networks in a collaborative environment. In particular, we focus on ISPs that cooperate among trusted partners. We found that the effects of a large-scale cyber attack can be significantly reduced using the moving-target defense and Software Defined Networking. Moreover, we show that Software Defined Networking is an appropriate approach to enforce implementation of the moving target defense and thus mitigate the effects caused by large-scale cyber attacks

    Boron Insertion into the N≡N Bond of a Tungsten Dinitrogen Complex

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    The 1,3-addition of 1,2-diaryl-1,2-dibromodiboranes (B2Br2Ar2) to trans-[W(N2)2(dppe)2] (dppe = κ2-(Ph2PCH2)2), which is accompanied by a Br–Ar substituent exchange between the two boron atoms, is followed by a spontaneous rearrangement of the resulting tungsten diboranyldiazenido complex to a 2-aza-1,3-diboraallenylimido complex displaying a linear, cumulenic B=N=B moiety. This rearrangement involves the splitting of both the B–B and N=N bonds of the N2B2 ligand, formal insertion of a BAr boranediyl moiety into the N=N bond, and coordination of the remaining BArBr boryl moiety to the terminal nitrogen atom. Density functional theory calculations show that the reaction proceeds via a cyclic NB2 intermediate, followed by dissociation into a tungsten nitrido complex and a linear boryliminoborane, which recombine by adduct formation between the nitrido ligand and the electron-deficient iminoborane boron atom. The linear B=N=B moiety also undergoes facile 1,2-addition of Brønsted acids (HY = HOPh, HSPh, and H2NPh) with concomitant Y–Br substituent exchange at the terminal boron atom, yielding cationic (borylamino)borylimido tungsten complexes

    Quantitative fatty acid signature analysis reveals a high level of dietary specialization in killer whales across the North Atlantic

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    Quantifying the diet composition of apex marine predators such as killer whales (Orcinus orca) is critical to assessing their food web impacts. Yet, with few exceptions, the feeding ecology of these apex predators remains poorly understood. Here, we use our newly validated quantitative fatty acid signature analysis (QFASA) approach on nearly 200 killer whales and over 900 potential prey to model their diets across the 5000 km span of the North Atlantic. Diet estimates show that killer whales mainly consume other whales in the western North Atlantic (Canadian Arctic, Eastern Canada), seals in the mid-North Atlantic (Greenland), and fish in the eastern North Atlantic (Iceland, Faroe Islands, Norway). Nonetheless, diet estimates also varied widely among individuals within most regions. This level of inter-individual feeding variation should be considered for future ecological studies focusing on killer whales in the North Atlantic and other oceans. These estimates reveal remarkable population- and individual-level variation in the trophic ecology of these killer whales, which can help to assess how their predation impacts community and ecosystem dynamics in changing North Atlantic marine ecosystems. This new approach provides researchers with an invaluable tool to study the feeding ecology of oceanic top predators

    Maternal Perception of Child Weight Among Mexicans in California and Mexico

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    The prevalence of childhood overweight is high in Mexican immigrant communities in the United States. Understanding mother’s perceptions of child weight in immigrants’ country of origin may help to understand this high prevalence. The goal of this study was to examine and compare mothers’ perception of weight in Mexico (MX) and in an immigrant community in California (CA). We assessed perceptions of child weight using a pictorial scale with 314 mothers of 5-year-old children in MX and 60 mothers of 5 year-old-children in CA. We compared maternal reports with children’s objectively measured weight. Using chi-square and Analysis of Variance, we investigated associations of maternal perception of and satisfaction with weight according to socio-demographic characteristics. Mothers were more likely to underestimate their children’s weight in CA than in MX. On average, CA mothers wanted their children to be smaller than they currently were and mothers in MX wanted their children to be bigger than they currently were. This differed by weight status in CA with mothers of normal weight and at-risk-for-overweight children wanting them to be bigger and mothers of overweight children wanting them to be smaller. In order for programs to be effective, mothers must be able to recognize their children as overweight and want to address it. Because underestimation of weight and a desire for a larger size is common in this population, programs to address overweight may be more effective if they focus on alternative benefits of weight control strategies, such as healthy child development
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