Evaluation of satellite imagery as an information service for investigating land use and natural resources (Skylab)

There are no author-identified significant results in this report

On the properties of surface reconstructed silicon nanowires

We study by means of density-functional calculations the role of lateral surface reconstructions in determining the electrical properties of silicon nanowires. The different lateral reconstructions are explored by relaxing all the nanowires with crystalline bulk silicon structure and all possible ideal facets that correspond to an average diameter of 1.5 nm. We show that the reconstruction induces the formation of ubiquitous surface states that turn the wires into semi-metallic or metallic

One hundred angstrom niobium wire

Composite of fine niobium wires in copper is used to study the size and proximity effects of a superconductor in a normal matrix. The niobium rod was drawn to a 100 angstrom diameter wire on a copper tubing

Short oestrous cycles in sheep during anoestrus involve defects in progesterone biosynthesis and luteal neovascularisation

Anoestrous ewes can be induced to ovulate by the socio-sexual, 'ram effect'. However, in some ewes the induced ovulation is followed by an abnormally short luteal phase causing a so called, "short cycle". The defect responsible for this luteal dysfunction has not been identified. In this experiment we investigated ovarian and uterine factors implicated in male-induced short cycles in anoestrus ewes using a combined endocrine and molecular strategy. Prior to ovulation, we were able to detect a moderate loss of thecal expression of steroid acute regulatory protein (STAR) in ewes that had not received progesterone priming (which prevents short cycles). At and following ovulation we were able to identify significant loss of expression of genes coding key proteins involved in the biosynthesis of progesterone (STAR, CYP11A1, HSD3B) as well as genes coding proteins critical for vascular development during early luteal development (VEGFA, VEGFR2) suggesting dysfunction in at least two pathways critical for normal luteal function. Furthermore, these changes were associated with a significant reduction of progesterone production and luteal weight. Additionally, we cast doubt on the proposed uterine-mediated effect of prostaglandin F2α as a cause of short cycles by demonstrating both the dysregulation of luteal expression of the PGF receptor, which mediates the luteal effects of PGF2α, and by finding no significant changes in the circulating concentrations of PGFM, the principal metabolite of PGF2α in ewes with short cycles. This study is the first of its kind to examine concurrently, the endocrine and molecular events in the follicular and early luteal stages of the short cycle

Chemical genetics : receptor-ligand pairs for rapid manipulation of neuronal activity

PMID: 22119143 [PubMed - indexed for MEDLINE] PMCID: PMC3294416 Free PMC ArticlePeer reviewedPublisher PD

Ro 15-4513 Antagonizes Alcohol-Induced Sedation in Mice Through aß¿2-type GABA(A) Receptors

Peer reviewedPublisher PD

Adaptive information search and decision making over single and repeated plays

For over 50 years expected value and expected utility theory has been challenged by behavioral findings in repeated and single plays of risky gambles. The inherent long-term nature of these models has been found to be at odds with preferences indicating short-term maximization in single play situations. With the present study we provide further evidence on the distinction between long-term and short-term oriented behavior. Evaluating experiencedbased decisions over repeated and single play situations we demonstrate that both choice preferences and search behavior change in response to long and short-term framing. This suggests different cognitive approaches for single and repeated play situations, with single decisions often favoring risk-aversion and therefore the underweighting of rare events. These findings are in line with alternative models of risky choice as for example proposed by Lopes (1996) and also the literature on statedependent foraging

On the formation/dissolution of equilibrium droplets

We consider liquid-vapor systems in finite volume $V\subset\R^d$ at parameter values corresponding to phase coexistence and study droplet formation due to a fixed excess $\delta N$ of particles above the ambient gas density. We identify a dimensionless parameter $\Delta\sim(\delta N)^{(d+1)/d}/V$ and a \textrm{universal} value \Deltac=\Deltac(d), and show that a droplet of the dense phase occurs whenever \Delta>\Deltac, while, for \Delta<\Deltac, the excess is entirely absorbed into the gaseous background. When the droplet first forms, it comprises a non-trivial, \textrm{universal} fraction of excess particles. Similar reasoning applies to generic two-phase systems at phase coexistence including solid/gas--where the ``droplet'' is crystalline--and polymorphic systems. A sketch of a rigorous proof for the 2D Ising lattice gas is presented; generalizations are discussed heuristically.Comment: An announcement of a forthcoming rigorous work on the 2D Ising model; to appear in Europhys. Let