1,222 research outputs found

    DAIRY MARKETS, POLICIES, AND TRADE IN EASTERN EUROPE AND THE FORMER SOVIET UNION

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    This paper was presented at the INTERNATIONAL TRADE IN LIVESTOCK PRODUCTS SYMPOSIUM in Auckland, New Zealand, January 18-19, 2001. The Symposium was sponsored by: the International Agricultural Trade Research Consortium, the Venture Trust, Massey University, New Zealand, and the Centre for Applied Economics and Policy Studies, Massey University. Dietary changes, especially in developing countries, are driving a massive increase in demand for livestock products. The objective of this symposium was to examine the consequences of this phenomenon, which some have even called a "revolution." How are dietary patterns changing, and can increased demands for livestock products be satisfied from domestic resources? If so, at what cost? What will be the flow-on impacts, for example, in terms of increased demands for feedgrains and the pressures for change within marketing systems? A supply-side response has been the continued development of large-scale, urban-based industrial livestock production systems that in many cases give rise to environmental concerns. If additional imports seem required, where will they originate and what about food security in the importing regions? How might market access conditions be re-negotiated to make increased imports achievable? Other important issues discussed involved food safety, animal health and welfare and the adoption of biotechnology, and their interactions with the negotiation of reforms to domestic and trade policies. Individual papers from this conference are available on AgEcon Search. If you would like to see the complete agenda and set of papers from this conference, please visit the IATRC Symposium web page at: http://www1.umn.edu/iatrc.intro.htmAgricultural and Food Policy, Marketing, International Relations/Trade,

    Out-of-plane focusing grating couplers for silicon photonics integration with optical MRAM technology

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    We present the design methodology and experimental characterization of compact out-of-plane focusing grating couplers for integration with magnetoresistive random access memory technology. Focusing grating couplers have recently found attention as layer-couplers for photonic-electronic integration. The components we demonstrate are designed for a wavelength of 1550 nm, fabricated in a standard 220 nm SOI photonic platform and optimized given the fabrication restrictions for standard 193-nm UV lithography. For the first time, we extend the design based on the phase matching condition to a two-dimensional (2-D) grating design with two optical input ports. We further present the experimental characterization of the focusing behaviour by spatially probing the emitted beam with a tapered-and-lensed fiber and demonstrate the polarization controlling capabilities of the 2-D FGCs

    Glassy Phase of Optimal Quantum Control

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    We study the problem of preparing a quantum many-body system from an initial to a target state by optimizing the fidelity over the family of bang-bang protocols. We present compelling numerical evidence for a universal spin-glass-like transition controlled by the protocol time duration. The glassy critical point is marked by a proliferation of protocols with close-to-optimal fidelity and with a true optimum that appears exponentially difficult to locate. Using a machine learning (ML) inspired framework based on the manifold learning algorithm t-SNE, we are able to visualize the geometry of the high-dimensional control landscape in an effective low-dimensional representation. Across the transition, the control landscape features an exponential number of clusters separated by extensive barriers, which bears a strong resemblance with replica symmetry breaking in spin glasses and random satisfiability problems. We further show that the quantum control landscape maps onto a disorder-free classical Ising model with frustrated nonlocal, multibody interactions. Our work highlights an intricate but unexpected connection between optimal quantum control and spin glass physics, and shows how tools from ML can be used to visualize and understand glassy optimization landscapes.Comment: Modified figures in appendix and main text (color schemes). Corrected references. Added figures in SI and pseudo-cod

    Modelling understorey dynamics in temperate forests under global change : challenges and perspectives

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    The understorey harbours a substantial part of vascular plant diversity in temperate forests and plays an important functional role, affecting ecosystem processes such as nutrient cycling and overstorey regeneration. Global change, however, is putting these understorey communities on trajectories of change, potentially altering and reducing their functioning in the future. Developing mitigation strategies to safeguard the diversity and functioning of temperate forests in the future is challenging and requires improved predictive capacity. Process-based models that predict understorey community composition over time, based on first principles of ecology, have the potential to guide mitigation endeavours but such approaches are rare. Here, we review fourteen understorey modelling approaches that have been proposed during the last three decades. We evaluate their inclusion of mechanisms that are required to predict the impact of global change on understorey communities. We conclude that none of the currently existing models fully accounts for all processes that we deem important based on empirical and experimental evidence. Based on this review, we contend new models are needed to project the complex impacts of global change on forest understoreys. Plant functional traits should be central to such future model developments, as they drive community assembly processes and provide valuable information on the functioning of the understorey. Given the important role of the overstorey, a coupling of understorey models to overstorey models will be essential to predict the impact of global change on understorey composition and structure, and how it will affect the functioning of temperate forests in the future

    Regulated Inositol‐Requiring Protein 1‐Dependent Decay as a Mechanism of Corin RNA and Protein Deficiency in Advanced Human Systolic Heart Failure

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    BACKGROUND: The compensatory actions of the endogenous natriuretic peptide system require adequate processing of natriuretic peptide pro‐hormones into biologically active, carboxyl‐terminal fragments. Natriuretic peptide pro‐peptide processing is accomplished by corin, a transmembrane serine protease expressed by cardiomyocytes. Brain natriuretic peptide (BNP) processing is inadequate in advanced heart failure and is independently associated with adverse outcomes; however, the molecular mechanisms causing impaired BNP processing are not understood. We hypothesized that the development of endoplasmic reticulum stress in cardiomyocytes in advanced heart failure triggers inositol‐requiring protein 1 (IRE1)‐dependent corin mRNA decay, which would favor a molecular substrate favoring impaired natriuretic peptide pro‐peptide processing. METHODS AND RESULTS: Two independent samples of hearts obtained from patients with advanced heart failure at transplant demonstrated that corin RNA was reduced as Atrial natriuretic peptide (ANP)/BNP RNA increased. Increases in spliced X‐box protein 1, a marker for IRE1‐endoribonuclease activity, were associated with decreased corin RNA. Moreover, ≈50% of the hearts demonstrated significant reductions in corin RNA and protein as compared to the nonfailing control sample. In vitro experiments demonstrated that induction of endoplasmic reticulum stress in cultured cardiomyocytes with thapsigargin activated IRE1s endoribonuclease activity and time‐dependent reductions in corin mRNA. In HL‐1 cells, overexpression of IRE1 activated IRE1 endoribonuclease activity and caused corin mRNA decay, whereas IRE1‐RNA interference with shRNA attenuated corin mRNA decay after induction of endoplasmic reticulum stress with thapsigargin. Pre‐treatment of cells with Actinomycin D to inhibit transcription did not alter the magnitude or time course of thapsigargin‐induced corin mRNA decline, supporting the hypothesis that this was the result of IRE1‐mediated corin mRNA degradation. CONCLUSIONS: These data support the hypothesis that endoplasmic reticulum stress‐mediated, IRE1‐dependent targeted corin mRNA decay is a mechanism leading to corin mRNA resulting in corresponding corin protein deficiency may contribute to the pathophysiology of impaired natriuretic peptide pro‐hormone processing in humans processing in humans with advanced systolic heart failure

    Evanescently-coupled hybrid III-V/silicon laser based on DVS-BCB bonding

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    © 2014 IEEE. Controllable electrical breakdown of multiwall nanotubes (MWNTs) is studied utilizing the atomic force microscopy (AFM). Electrical breakdown has been known as the way to fundamentally understand the electrical properties of nanotubes and an approach to develop MWNT based transistors and sensors. Normally, electrical breakdown was known to be happened in the center of MWNT because of the thermal accumulation. However, considering the effect of thermal dissipation, the electrical breakdown could be mechanically controlled by an additional heat sink, which could be the substrate of MWNT device. Therefore, the electrical breakdown process is controllable through controlling Joule heating and thermal dissipation. In this research, we study the crucial factors that affect the electrical breakdown. The AFM based nano robot is used to measure the conductance distribution, and manipulate the three dimensional structure of MWNT in order to change the position of heat sink to control the location where electrical breakdown happened. The controllable electrical breakdown is an alternative approach for conducting bandgap engineering in nanodevice and fabricating high performance nano sensors and transistors.Link_to_subscribed_fulltex

    Using Feedback to Mitigate Coordination and Threshold Problems in Iterative Combinatorial Auctions

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    Package bids, i.e., bids on sets of items, are an essential aspect of combinatorial auctions. They can allow bidders to accurately express their preferences. However, bidders on packages consisting of few items are often unable to outbid provisionally winning bids on large packages. To resolve this, both coordination as well as cooperation are needed. Coordination, since smaller bidders need to bid on packages that are disjoint; cooperation, since typically bid increases from more than one bidder are required to overcome the threshold to outbid a larger package bid. The authors design an information system that supports the implementation of an iterative combinatorial auction; this system is specifically aimed at helping bidders overcome coordination and threshold problems. They study the effect of information feedback on the behavior of bidders in different auction settings. The authors test this in an experimental setting using human bidders, varying feedback from very basic information about provisionally winning bids/prices, to providing more advanced concepts such as winning and deadness levels, and coalitional feedback. The experiment indicates that coalitional feedback has a positive impact on economic efficiency in cases where difficult threshold problems arise; however, it appears to have an adverse effect when threshold problems are easy
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