484 research outputs found

    Conservation Auctions and Compliance: Theory and Evidence from Laboratory Experiments

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    Poster prepared for presentation at the Agricultural & Applied Economics Association 2010 AAEA,CAES, & WAEA Joint Annual Meeting, Denver, Colorado, July 25-27, 2010.Auctions, Conservation contracting, Compliance, Environmental Economics and Policy, C91, D44, Q24,

    Preparation of Rat Brain Aggregate Cultures for Neuron and Glia Development Studies

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    An in vitro system that recapitulates the development and differentiation of progenitors into mature neurons and glia in the central nervous system (CNS) would provide a powerful platform for neuroscientists to investigate axo-glial interactions, properties and differentiation of multipotent progenitors, and progression of oligodendroglial lineage cells at the cellular and molecular level. We describe here a CNS aggregate culture system from embryonic rat forebrains, which can be maintained in a serum-free medium up to 3-4 weeks and is used in our laboratory as a model to study neuron-glia interaction and CNS myelination. This video clip will demonstrate how to isolate and grow these CNS aggregate cultures from E16 rat brain. Furthermore, from the same brain dissection, highly enriched regular dissociated neuronal cultures can be readily obtained and used for various studies on CNS neurons or used for co-cultures with other cells

    Auctioning Conservation Contracts and Evaluating the Risk Attitudes of Farmers: Economic Experiments in Japan

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    Agri-environmental programs in Japan have generally been promoted through the provision of fixed payments for certain environment-friendly farming and management practices. However, the auctioning of agrienvironmental contracts is a noteworthy alternative for the furtherance of such programs. Conservation auctions are used to enhance the cost-effectiveness of public expenses and have been employed in practice as well as tested in various pilot projects in some countries. This study uses an experimental economics method to factor the risk attitude of participants into a comparison of uniform price (UP) auctions and discriminatory price (DP) auctions. Although some studies have compared fixed payments, UP auctions, and DP auctions, the superiority or inferiority of these strategies depends on the settings of an experiment. Consequently, experiments reflecting the Japanese situation could provide further insight into the advantages of each of these methods, and be used to guide policy design. In addition, the study also examines the effects of participants’ risk attitudes on auction performance. Its principal conclusion is that DP auctions outperform UP auctions; this is in line with the findings of previous studies. This empirical research furthers our understanding of environmental auctions in a first step toward the design of such auctions, but field experiments using real farmers should be conducted in order to help corroborate research conclusions before these are applied to the real world.conservation auction, experimental economics, risk attitude, environment-friendly farming, Agribusiness, Agricultural and Food Policy, Consumer/Household Economics, Environmental Economics and Policy, Farm Management,

    Opossum APOBEC1 is a DNA mutator with retrovirus and retroelement restriction activity

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    APOBEC3s (A3s) are single-stranded DNA cytosine deaminases that provide innate immune defences against retroviruses and mobile elements. A3s are specific to eutherian mammals because no direct homologs exist at the syntenic genomic locus in metatherian (marsupial) or prototherian (monotreme) mammals. However, the A3s in these species have the likely evolutionary precursors, the antibody gene deaminase AID and the RNA/DNA editing enzyme APOBEC1 (A1). Here, we used cell culture-based assays to determine whether opossum A1 restricts the infectivity of retroviruses including human immunodeficiency virus type 1 (HIV-1) and the mobility of LTR/non-LTR retrotransposons. Opossum A1 partially inhibited HIV-1, as well as simian immunodeficiency virus (SIV), murine leukemia virus (MLV), and the retrotransposon MusD. The mechanism of inhibition required catalytic activity, except for human LINE1 (L1) restriction, which was deamination-independent. These results indicate that opossum A1 functions as an innate barrier to infection by retroviruses such as HIV-1, and controls LTR/non-LTR retrotransposition in marsupials

    Physical modelling of backward erosion piping in foundation beneath levee

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    Centrifuge model tests are performed to observe piping progression in foundation beneath levee and to examine influence of repeated seepage and thickness of foundation ground on piping progression. Once the pipe is formed beneath the levee, hydraulic gradient upstream of the pipe tip becomes larger while that along the pipe becomes rather small. Shift of this large hydraulic gradient position to the upstream with rise of the flood water level leads to the large subsidence of the slope in the protected side and marked increase in flow rate. Repeated seepage and thickness of the permeable foundation layer have influence on stability of levee against piping. Repeated seepage makes the piping progression faster and levee vulnerable to the piping formation. With the thinner permeable foundation layer beneath the levee, the levee is at higher risk to cause brittle failure while the required hydraulic gradient to cause piping is larger

    The antiretroviral potency of APOBEC1 deaminase from small animal species

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    Although the role of the APOBEC3-dependent retroelement restriction system as an intrinsic immune defense against human immunodeficiency virus type1 (HIV-1) infection is becoming clear, only the rat ortholog of mammalian APOBEC1s (A1) thus far has been shown to possess antiviral activity. Here, we cloned A1 cDNAs from small animal species, and showed that similar to rat A1, both wild-type and Δvif HIV-1 infection was inhibited by mouse and hamster A1 (4- to 10-fold), whereas human A1 had negligible effects. Moreover, rabbit A1 significantly reduced the infectivity of both HIV-1 virions (>300-fold), as well as that of SIVmac, SIVagm, FIV and murine leukemia virus. Immunoblot analysis showed that A1s were efficiently incorporated into the HIV-1 virion, and their packaging is mediated through an interaction with the nucleocapsid Gag domain. Interestingly, there was a clear accumulation of particular C-T changes in the genomic RNAs of HIV-1 produced in their presence, with few G-A changes in the proviral DNA. Together, these data reveal that A1 may function as a defense mechanism, regulating retroelements in a wide range of mammalian species

    A case of absent right and persistent left superior vena cava

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    BACKGROUND AND PURPOSE: Our case report deals with the importance of detailed echocardiographic examination for differential diagnosis of coronary sinus dilation and development of abnormalities of great thoracic veins. CASE PRESENTATION: A 49-year-old man underwent transthoracic echocardiography for atypical chest pain. A dilated coronary sinus was found and venous contrast echocardiography raised the suspicion of absent right and persistent left superior vena cava. Transesophageal echocardiography showed absence of right superior vena cava. The echocardiographic findings were confirmed by upper venous digital subtraction cavography. CONCLUSION: combination of agenesia of right SVC and isolated persistent left SVC in adult patients is a very rare abnormality. Both clinicians and sonographers should be alerted to the possible presence of this combined venous anomaly. Transthoracic echocardiograpy – including agitated saline infusion to the antecubital vein – is an important diagnostic tool for accurate diagnosis of this congenital thoracic venous malformation

    Structure-activity correlations for Brønsted acid, Lewis Acid, and photocatalyzed reactions of exfoliated crystalline niobium oxides

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    Exfoliated crystalline niobium oxides that contain exposed but interconnected NbO6 octahedra with different degrees of structural distortion and defects are known to catalyze Brønsted acid (BA), Lewis acid (LA), and photocatalytic (PC) reactions efficiently but their structure–activity relationships are far from clear. Here, three exfoliated niobium oxides, namely, HSr2Nb3O10, HCa2Nb3O10, and HNb3O8, are synthesized, characterized extensively, and tested for selected BA, LA, and PC reactions. The structural origin for BA is associated mainly with acidic hydroxyl groups of edge-shared NbO6 octahedra as proton donors; that of LA is associated with the vacant band position of Nb5+ to receive electron pairs from substrate; and that of PC is associated with the terminal Nb=O of NbO6 octahedra for photon capture and charge transfer to long-lived surface adsorbed substrate complex through associated oxygen vacancies in close proximity. It is believed that an understanding of the structure–activity relationships could lead to the tailored design of NbOx catalysts for industrially important reactions
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