3,310 research outputs found
Endogenous timing factors in bird migration
Several species of warbler birds were observed in an effort to determine what initiates and terminates migration. Environmental and endogenous timing mechanisms were analyzed. The results indicate that endogenous stimuli are dominant factors for bird migration especially for long distances. It was concluded that environmental factors act as an assist mechanism
The sub prime crisis : implications for emerging markets
This paper discusses some of the key characteristics of the U.S. subprime mortgage boom and bust, contrasts them with characteristics of emerging mortgage markets, and makes recommendations for emerging market policy makers. The crisis has raised questions in the minds of many as to the wisdom of extending mortgage lending to low and moderate income households. It is important to note, however,that prior to the growth of subprime lending in the 1990s, U.S. mortgage markets already reached low and moderate-income households without taking large risks or suffering large losses. In contrast, in most emerging markets, mortgage finance is a luxury good, restricted to upper income households. As policy makers in emerging market seek to move lenders down market, they should adopt policies that include a variety of financing methods and should allow for rental or purchase as a function of the financial capacity of the household. Securitization remains a useful tool when developed in the context of well-aligned incentives and oversight. It is possible to extend mortgage lending down market without repeating the mistakes of the subprime boom and bust.Debt Markets,,Access to Finance,Bankruptcy and Resolution of Financial Distress,Emerging Markets
Proteomics for rejection diagnosis in renal transplant patients: where are we now?
Rejection is one of the key factors that determine the long-term allograft function and survival in renal transplant patients. Reliable and timely diagnosis is important to treat rejection as early as possible. Allograft biopsies are not suitable for continuous monitoring of rejection. Thus, there is an unmet need for non-invasive methods to diagnose acute and chronic rejection. Proteomics in urine and blood samples has been explored for this purpose in 29 studies conducted since 2003. This review describes the different proteomic approaches and summarizes the results from the studies that examined proteomics for the rejection diagnoses. The potential limitations and open questions in establishing proteomic markers for rejection are discussed, including ongoing trials and future challenges to this topic
Automated detection of block falls in the north polar region of Mars
We developed a change detection method for the identification of ice block
falls using NASA's HiRISE images of the north polar scarps on Mars. Our method
is based on a Support Vector Machine (SVM), trained using Histograms of
Oriented Gradients (HOG), and on blob detection. The SVM detects potential new
blocks between a set of images; the blob detection, then, confirms the
identification of a block inside the area indicated by the SVM and derives the
shape of the block. The results from the automatic analysis were compared with
block statistics from visual inspection. We tested our method in 6 areas
consisting of 1000x1000 pixels, where several hundreds of blocks were
identified. The results for the given test areas produced a true positive rate
of ~75% for blocks with sizes larger than 0.7 m (i.e., approx. 3 times the
available ground pixel size) and a false discovery rate of ~8.5%. Using blob
detection we also recover the size of each block within 3 pixels of their
actual size
On optimal control in a nonlinear interface problem described by hemivariational inequalities
The purpose of this paper is three-fold. Firstly we attack a nonlinear
interface problem on an unbounded domain with nonmonotone set-valued
transmission conditions. The investigated problem involves a nonlinear monotone
partial differential equation in the interior domain and the Laplacian in the
exterior domain. Such a scalar interface problem models nonmonotone frictional
contact of elastic infinite media. The variational formulation of the interface
problem leads to a hemivariational inequality (HVI), which however lives on the
unbounded domain, and thus cannot analyzed in a reflexive Banach space setting.
By boundary integral methods we obtain another HVI that is amenable to
functional analytic methods using standard Sobolev spaces on the interior
domain and Sobolev spaces of fractional order on the coupling boundary.
Secondly broadening the scope of the paper, we consider extended real-valued
HVIs augmented by convex extended real-valued functions. Under a smallness
hypothesis, we provide existence and uniqueness results, also establish a
stability result with respect to the extended real-valued function as
parameter. Thirdly based on the latter stability result, we prove the existence
of optimal controls for four kinds of optimal control problems: distributed
control on the bounded domain, boundary control, simultaneous
distributed-boundary control governed by the interface problem, as well as
control of the obstacle driven by a related bilateral obstacle interface
problem.Comment: 26 pages, no figures. arXiv admin note: text overlap with
arXiv:2112.1217
Casos exitosos de financiamiento hipotecario en América Latina
Entre las lecciones de las experiencias latinoamericanas de financiamiento hipotecario, especialmente en Chile, MĂ©xico y Colombia, están la importancia de la demanda domĂ©stica por tĂtulos de largo plazo, la implementaciĂłn de polĂticas sistemáticas para el desarrollo del mercado hipotecario, y el rol del Estado, el cual debe apoyar el crecimiento del mercado en vez de reemplazarlo.
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