Progress toward the development of an airfoil icing analysis capability

The NASA-Lewis aircraft icing analysis program is composed of three major sub-programs. These sub-programs are ice accretion simulation, performance degradation evaluation, and ice protection system evaluation. These topics cover all areas of concern related to the simulation of aircraft icing and its consequences. The motivation for these activities is twofold, reduction of time and effort required in experimental programs and the ability to provide reliable information for aircraft certification in icing, over the complete range of environmental conditions. In addition to the analytical activities associated with development of these codes, several experimental programs are underway to provide verification information for existing codes. These experimental programs are also used to investigate the physical processes associated with ice accretion and removal for improvement of present analytical models. The NASA-Lewis icing analysis program is thus striving to provide a full range of analytical tools necessary for evaluation of the consequences of icing and of ice protection systems

Job Growth in Early Transition: Comparing Two Paths

Small start-up firms are the engine of job creation in early transition and yet little is known about the characteristics of this new sector. We seek to identify patterns of job growth in this sector in terms of niches left from central planning and ask about differences in job creation across two different transition economies: Estonia, which experienced rapid destruction of the pre-existing firms, and the Czech Republic, which reduced the old sector gradually. We find job growth within industries to be quantitatively more important than job growth due to across-industry reallocation. Furthermore, the industrial composition of startups is strikingly similar in the two countries. We offer convergence to "western" industry firm-size distributions as an explanation. We also find regularities in wage evolution across new and old firms, including small differences in job quality across the two transition paths.http://deepblue.lib.umich.edu/bitstream/2027.42/39888/3/wp503.pd

Self-similar magnetoresistance of Fibonacci ultrathin magnetic films

We study numerically the magnetic properties (magnetization and magnetoresistance) of ultra-thin magnetic films (Fe/Cr) grown following the Fibonacci sequence. We use a phenomenological model which includes Zeeman, cubic anisotropy, bilinear and biquadratic exchange energies. Our physical parameters are based on experimental data recently reported, which contain biquadratic exchange coupling with magnitude comparable to the bilinear exchange coupling. When biquadratic exchange coupling is sufficiently large a striking self-similar pattern emerges.Comment: 5 pages, 5 EPS figures, REVTeX, accepted for publication in Phys. Rev.

Value at Risk models with long memory features and their economic performance

We study alternative dynamics for Value at Risk (VaR) that incorporate a slow moving component and information on recent aggregate returns in established quantile (auto) regression models. These models are compared on their economic performance, and also on metrics of first-order importance such as violation ratios. By better economic performance, we mean that changes in the VaR forecasts should have a lower variance to reduce transaction costs and should lead to lower exceedance sizes without raising the average level of the VaR. We find that, in combination with a targeted estimation strategy, our proposed models lead to improved performance in both statistical and economic terms

Silicon-based molecular electronics

Molecular electronics on silicon has distinct advantages over its metallic counterpart. We describe a theoretical formalism for transport through semiconductor-molecule heterostructures, combining a semi-empirical treatment of the bulk silicon bandstructure with a first-principles description of the molecular chemistry and its bonding with silicon. Using this method, we demonstrate that the presence of a semiconducting band-edge can lead to a novel molecular resonant tunneling diode (RTD) that shows negative differential resistance (NDR) when the molecular levels are driven by an STM potential into the semiconducting band-gap. The peaks appear for positive bias on a p-doped and negative for an n-doped substrate. Charging in these devices is compromised by the RTD action, allowing possible identification of several molecular highest occupied (HOMO) and lowest unoccupied (LUMO) levels. Recent experiments by Hersam et al. [1] support our theoretical predictions.Comment: Author list is reverse alphabetical. All authors contributed equally. Email: rakshit/liangg/ ghosha/[email protected]

Addressing unmet basic resource needs as part of chronic cardiometabolic disease management

IMPORTANCE It is unclear if helping patients meet resource needs, such as difficulty affording food, housing, or medications, improves clinical outcomes. OBJECTIVE To determine the effectiveness of the Health Leads program on improvement in systolic and diastolic blood pressure (SBP and DBP, respectively), low-density lipoprotein cholesterol (LDL-C) level, and hemoglobin A1c (HbA1c) level. DESIGN, SETTING, AND PARTICIPANTS A difference-in-difference evaluation of the Health Leads program was conducted from October 1, 2012, through September 30, 2015, at 3 academic primary care practices. Health Leads consists of screening for unmet needs at clinic visits, and offering those who screen positive to meet with an advocate to help obtain resources, or receive brief information provision. MAIN OUTCOMES AND MEASURES Changes in SBP, DBP, LDL-C level, and HbA1c level.We compared those who screened positive for unmet basic needs (Health Leads group) with those who screened negative, using intention-to-treat, and, secondarily, between those who did and did not enroll in Health Leads, using linear mixed modeling, examining the period before and after screening. RESULTS A total of 5125 people were screened, using a standardized form, for unmet basic resource needs; 3351 screened negative and 1774 screened positive. For those who screened positive, the mean age was 57.6 years and 1811 (56%) were women. For those who screened negative, the mean age was 56.7 years and 909 (57%) were women. Of 5125 people screened, 1774 (35%) reported at least 1 unmet need, and 1021 (58%) of those enrolled in Health Leads. Median follow-up for those who screened positive and negative was 34 and 32 months, respectively. In unadjusted intention-to-treat analyses of 1998 participants with hypertension, the Health Leads group experienced greater reduction in SBP (differential change, ?1.2; 95%CI, ?2.1 to ?0.4) and DBP (differential change, ?1.0; 95%CI, ?1.5 to ?0.5). For 2281 individuals with an indication for LDL-C level lowering, results also favored the Health Leads group (differential change, ?3.7; 95%CI ?6.7 to ?0.6). For 774 individuals with diabetes, the Health Leads group did not show HbA1c level improvement (differential change, ?0.04%; 95%CI, ?0.17%to 0.10%). Results adjusted for baseline demographic and clinical differences were not qualitatively different. Among those who enrolled in Health Leads program, there were greater BP and LDL-C level improvements than for those who declined (SBP differential change ?2.6; 95%CI,?3.5 to ?1.7; SBP differential change, ?1.4; 95%CI, ?1.9 to ?0.9; LDL-C level differential change, ?6.3; 95%CI, ?9.7 to ?2.8). CONCLUSIONS AND RELEVANCE Screening for and attempting to address unmet basic resource needs in primary care was associated with modest improvements in blood pressure and lipid, but not blood glucose, levels

Differential hRad17 expression by histologic subtype of ovarian cancer

<p>Abstract</p> <p>Background</p> <p>In the search for unique ovarian cancer biomarkers, ovarian specific cDNA microarray analysis identified hRad17, a cell cycle checkpoint protein, as over-expressed in ovarian cancer. The aim of this study was to validate this expression.</p> <p>Methods</p> <p>Immunohistochemistry was performed on 72 serous, 19 endometrioid, 10 clear cell, and 6 mucinous ovarian cancers, 9 benign ovarian tumors, and 6 normal ovarian tissue sections using an anti-hRad17 antibody. Western blot analysis and quantitative PCR were performed using cell lysates and total RNA prepared from 17 ovarian cancer cell lines and 6 normal ovarian epithelial cell cultures (HOSE).</p> <p>Results</p> <p>Antibody staining confirmed upregulation of hRad17 in 49.5% of ovarian cancer cases. Immunohistochemistry demonstrated that only 42% of serous and 47% of endometrioid subtypes showed overexpression compared to 80% of clear cell and 100% of mucinous cancers. Western blot confirmed overexpression of hRad17 in cancer cell lines compared to HOSE. Quantitative PCR demonstrated an upregulation of hRad17 RNA by 1.5-7 fold. hRad17 RNA expression differed by subtype.</p> <p>Conclusions</p> <p>hRad17 is over-expressed in ovarian cancer. This over-expression varies by subtype suggesting a role in the pathogenesis of these types. Functional studies are needed to determine the potential role of this protein in ovarian cancer.</p