Sensitivity of a superconducting nanowire detector for single ions at low energy

We report on the characterization of a superconducting nanowire detector for ions at low kinetic energies. We measure the absolute single-particle detection efficiency η and trace its increase with energy up to η = 100%. We discuss the influence of noble gas adsorbates on the cryogenic surface and analyze their relevance for the detection of slow massive particles. We apply a recent model for the hot-spot formation to the incidence of atomic ions at energies between 0.2 and 1 keV. We suggest how the differences observed for photons and atoms or molecules can be related to the surface condition of the detector and we propose that the restoration of proper surface conditions may open a new avenue for SSPD-based optical spectroscopy on molecules and nanoparticles.     

Preparation of injectable auto-forming alginate gel containing simvastatin with amorphous calcium phosphate as a controlled release medium and their therapeutic effect in osteoporosis model rat

Highly soluble amorphous calcium phosphate powder (ACP) was added to the alginate gel as a buffering agent, in an attempt to enable widely controlled release while avoiding an acidification of the gel-environment. Therapeutic effects of the ACP-containing alginate gel which slowly releases a drug, simvastatin, on osteoporosis model rats were examined. A model drug, simvastatin, incorporated in the alginate gel with ACP up to 0.5%, was continuously released for a long time under the acidic condition. The release rate was controlled by the amount of ACP, serving as a buffer to suppress acidity. When the alginate solution intramuscularly injected in the rat, a soft gel was formed in the injected site. Simvastatin released from the gel containing 0.5% of ACP showed high therapeutic effect on osteoporosis rat. Thus, the present injectable long-sustained release system is expected to be a novel drug delivery controlling device.     

A computational capacity resistance model (CaRM) for vertical ground-coupled heat exchangers

Several models are available in literature to simulate ground heat exchangers. In this paper an approach based on electrical analogy is presented, for this reason named CaRM (CApacity Resistance Model). In some cases several information are needed during design: both the borehole and the surrounding ground are affected by thermal exchange. The model here presented allows to consider the fluid flow pattern along the classical vertical ground heat exchangers as a single U-tube, a double U-tube or coaxial pipes. Besides, ground temperature at different distances from borehole are calculated, taking into account also the thermal interference between more boreholes. Starting from the supply temperature to the heat exchanger, the outlet fluid temperature is calculated and the ground temperature in each node, step by step. The model has been validated by means of a commercial software based on the finite differences method. Further comparisons have been carried out against data from a ground thermal response test and from the survey of an office building equipped with a ground coupled heat pump and vertical double U-tube heat exchangers. The agreement of results validates the model here presented.     

Do street youths' perceptions of their caregivers predict HIV-risk behavior?

This study examined street youths' perceptions of their caregivers and the association between these perceptions and HIV-risk behavior in a random probability sample of 715 12- to 23-year-old street youths from Los Angeles and San Diego, CA (mean age, 18.7 years). All participants had been homeless at some point during the past 12 months, with 70% recruited from nonshelter sites. Although youths reported high rates of hostility, unavailability, substance use, and legal problems among their caregivers, 86% reported that their caregivers had at least one attribute associated with support. Caregiver problems were associated with youth having had more sexual partners in the past 30 days and having higher risk drug use. High caregiver support was associated with more sexual partners and lower use of condoms with steady partners. Caregiver attributes did not predict condom use with transient partners. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Modeling uncertainties for passive microwave precipitation retrieval: evaluation of a case study

Physically based microwave spaceborne techniques for rainfall retrieval are usually trained by simulated cloud-radiation databases (CRDs) composed of cloud profiles and associated brightness temperatures (TBs). When generating the database, the evaluation of the associated modeling uncertainties is crucial for retrieval error estimation. However, this is extremely complex due to the large number of free parameters. In this work, a possible methodology for taking into account CRD-related modeling uncertainties is proposed. The methodology-fairly general-is here applied to a limited dataset (a cloud-model resolved numerical output of a tropical cyclone). The modeling errors are obtained from systematic TB sensitivity tests associated to several parameters: particle sizes, temperature, ice content, sea surface wind speed, viewing angle, footprint size, radiative transfer schemes, melting phase, and particle shape. TB uncertainties are eventually summarized in a modeling error covariance matrix representing the intrinsic variability of the generated CRD. For comparison with real observations, the TBs are simulated at the spatial resolution, viewing geometry and frequencies of the Tropical Rainfall Measuring Mission (TRMM) Microwave Imager (TMI). The matrix is evaluated with respect to TMI data in terms of an indicator called database matching index. Since they are based on a single case study and suffer from the lack of direct coupling of the radiative transfer with the cloud-resolving model, the provided results should not be considered an exhaustive evaluation of cloud-radiation modeling errors. Nevertheless, they may be considered a valuable starting point for error characterization, since extensions to larger databases could definitely improve modeling error budgets.     

Python中泛型函数应用案例

近几个星期，我跟同事一直在做一个编程项目。该项目需要一个命令行接口，我们利用的是Python标准类库中的cmd模块，再加上用Twisted编的～个网络层，最后完成了两种类：一种对应标准数据流（stdin，stdout，stderr）接口，另一种对应非标准数据流（如Twisted transport）接口。所有I/O接口（输入输出接口）都是命令行接口，我们大致使用了三种方法：     

Does clinical status change in anticipation of a PTSD disability examination?

Although there has been considerable research on forensic aspects of disability evaluations for mental health claims, there has been little focus on the clinical impact of disability system participation. Using a prospective design, we examined whether disability system participation affected psychiatric symptom and disability levels in claimants filing for VA disability benefits on the basis of posttraumatic stress disorder (PTSD). Claimants had high levels of PTSD symptoms and disability at the time of claim initiation. Modest increases in illness severity were observed at the time of the disability examination. Factors associated with symptom change were income level and employment status. Negative expectations about the disability claims process were associated with severity of PTSD symptoms, but not with change in symptom levels over time. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The Representation of Homophones: Evidence From the Distractor-Frequency Effect.

Current models of word production offer different accounts of the representation of homophones in the lexicon. The investigation of how the homophone status of a word affects lexical access can be used to test theories of lexical processing. In this study, homophones appeared as word distractors superimposed on pictures that participants named orally. The authors varied distractor frequency, a variable that has been shown to modulate the interference that distractors produce on picture naming. The results of 3 experiments converged in showing that words interfered in proportion to their individual frequency in the language, even if they have high-frequency homophone mates. This effect of specific-word frequency is compatible with models that assume (a) distinct lexical representations for the individual homophones and (b) that access to such representations is modulated by frequency. The authors discuss the extent to which current models of word production satisfy these constraints. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Polariscopic imaging and vibrational characterization of hybrid films for packaging

Polymeric films (low‐density polyethylene and oriented polypropylene) for packaging applications coated with organic–inorganic nanocomposite hybrids have been prepared by sol‐gel process. Tetraethoxysilane and two different organic phases, polyvinyl alcohol and a diblock copolymer polyethylene‐polyethylene glycol were used as precursors. Information about the hydrolysis and polycondensation degrees was obtained by investigating the vibrational features of the coatings by means of attenuated total reflectance‐Fourier transform infrared and Raman spectroscopies. Through a new polariscopic imaging technique, the bi‐dimensional maps of the optical anisotropy of the samples, both as‐prepared and under mechanical strain, were obtained. The maps showed inhomogeneous retardation and nearly flat azimuth distributions. The anisotropy properties of the samples depended mainly on the substrates and were not influenced by the coatings, while the optical transmission was slightly better for the tetraethoxysilane‐polyvinyl alcohol sample. Copyright © 2008 John Wiley & Sons, Ltd.     

Calculations of free energy barriers for local mechanisms of hydrogen diffusion in alanates

Brute force histogram calculation and a recently developed method to efficiently reconstruct the free energy profile of complex systems (the single-sweep method) are combined with ab initio molecular dynamics to study possible local mechanisms for the diffusion of hydrogen in sodium alanates. These compounds may help to understand key properties of solid state hydrogen storage materials. In this work, the identity of a mobile species observed in experiments characterizing the first dissociation reaction of sodium alanates is investigated. The activation barrier of two suggested processes for hydrogen diffusion in Na₃AlH₆ is evaluated and, by comparing our results with available experimental information, we are able to discriminate among them and to show that one is compatible with the observed signal while the other is not.