Large-scale simulations of intrinsic parameter fluctuations in nano-scale MOSFETs

Intrinsic parameter fluctuations have become a serious obstacle to the continued scaling of MOSFET devices, particularly in the sub-100 nm regime. The increase in intrinsic parameter fluctuations means that simulations on a statistical scale are necessary to capture device parameter distributions. In this work, large-scale simulations of samples of 100,000s of devices are carried out in order to accurately characterise statistical variability of the threshold voltage in a real 35 nm MOSFET. Simulations were performed for the two dominant sources of statistical variability – random discrete dopants (RDD) and line edge roughness (LER). In total ∼400,000 devices have been simulated, taking approximately 500,000 CPU hours (60 CPU years). The results reveal the true shape of the distribution of threshold voltage, which is shown to be positively skewed for random dopants and negatively skewed for line edge roughness. Through further statistical analysis and data mining, techniques for reconstructing the distributions of the threshold voltage are developed. By using these techniques, methods are demonstrated that allow statistical enhancement of random dopant and line edge roughness simulations, thereby reducing the computational expense necessary to accurately characterise their effects. The accuracy of these techniques is analysed and they are further verified against scaled and alternative device architectures. The combined effects of RDD and LER are also investigated and it is demonstrated that the statistical combination of the individual RDD and LER-induced distributions of threshold voltage closely matches that obtained from simulations. By applying the statistical enhancement techniques developed for RDD and LER, it is shown that the computational cost of characterising their effects can be reduced by 1–2 orders of magnitude

Validation of the Abbreviated Socio‑Political Control Scale for Youth (SPCS‑Y) Among Urban Girls of Color

This study tested and validated the factor structure of the abbreviated Sociopolitical Control Scale for Youth (SPCS-Y) among a sample of urban girls of color. Participants include (N = 830) urban girls of color from a northeastern United States community. Confirmatory Factor analyses (CFA) were conducted using AMOS Structural Equation Modeling Software. Cluster groups were created using Latent Class Cluster Analysis (LCA) and tested using Multivariate analysis of covariance (MANCOVA) with conceptually related variables. CFA results supported the two-factor structure of the abbreviated SPCS-Y among the sample. Following the creation of cluster groups, MANCOVA analyses revealed significant heterogeneity among cluster groups of participants on neighborhood sense of community, social support, ethnic identity, and lower levels of drug use. Findings support the factor structure of the SPCS-Y and its use to measure empowerment among girls of color. Results contribute significantly to the field of social work and encourages the importance of promoting strengths-based approaches among girls of color. Implications for social work practice with girls of color are conveyed in light of the need for reliable measurement tools for practitioners

The American Dream eludes many urban youth of color. And they think it's their own fault.

Segregation is not a thing of the past for young people of color in the US; many attend under-resourced and segregated school districts. Despite these disadvantages, America's leaders tell young people of color that they can achieve the "American Dream" via hard work and determination. In new research, David T. Lardier Jr., Kathryn G. Herr, Veronica R. Barrios, Pauline Garcia-Reid ..

Social exclusion among urban ethnic minority youth in the Northeast United States: A reflective view on community supportive structures

Social exclusion occurs as a combination of challenges (e.g., unemployment, high poverty, family conflict) that limits life opportunities. Social exclusion has been researched within European contexts, among middle-class families, and from quantitative perspectives. However, research on the topic among urban ethnic minority youth and using qualitative methodologies has remained elusive in the U.S. Although collaborative efforts between governmental institutions and community-based coalitions have helped develop intervention efforts to decrease social exclusion among youth in low-income urban areas, it continues to develop within families, communities, and societies. Therefore, this research explored experiences of social exclusion among low-income minority youth in an urban community in the Northeast U.S. Data were collected from nine focus groups (N = 58). The goal was to explore how urban ethnic minority youth understood social exclusion and the community resources they used to navigate its challenges. Findings included economic and societal exclusion in the form of economic deprivation and lack of appropriate safety nets. Although youth expressed a lack of community connection in the form of community exclusion, they applied a reflective view on how inequality shaped their lives, while discussing pathways towards social inclusion. This reflection was emphasized by the importance of developing bridging and bonding relationships (mentoring)

Decline in an Atlantic Puffin population : evaluation of magnitude and mechanisms

Funding: This study was funded annually by Fair Isle Bird Observatory Trust (www.fairislebirdobs.co.uk) with contributions from the Joint Nature Conservation Committee (jncc.defra.gov.uk). Funding was received from these two sources by Fair Isle Bird Observatory from 1986 to 2013. The Joint Nature Conservation Committee and Fair Isle Bird Observatory Trust supplied guidance on study design, data collection, analyses, preparation of the manuscript and the decision to publish.Peer reviewedPublisher PD

Osteoprotegerin reduces osteoclast resorption activity without affecting osteogenesis on nanoparticulate mineralized collagen scaffolds.

The instructive capabilities of extracellular matrix-inspired materials for osteoprogenitor differentiation have sparked interest in understanding modulation of other cell types within the bone regenerative microenvironment. We previously demonstrated that nanoparticulate mineralized collagen glycosaminoglycan (MC-GAG) scaffolds efficiently induced osteoprogenitor differentiation and bone healing. In this work, we combined adenovirus-mediated delivery of osteoprotegerin (AdOPG), an endogenous anti-osteoclastogenic decoy receptor, in primary human mesenchymal stem cells (hMSCs) with MC-GAG to understand the role of osteoclast inactivation in augmentation of bone regeneration. Simultaneous differentiation of osteoprogenitors on MC-GAG and osteoclast progenitors resulted in bidirectional positive regulation. AdOPG expression did not affect osteogenic differentiation alone. In the presence of both cell types, AdOPG-transduced hMSCs on MC-GAG diminished osteoclast-mediated resorption in direct contact; however, osteoclast-mediated augmentation of osteogenic differentiation was unaffected. Thus, the combination of OPG with MC-GAG may represent a method for uncoupling osteogenic and osteoclastogenic differentiation to augment bone regeneration

Response of angina and ischemia to long-term treatment in patients with chronic stable angina: A double-blind randomised individualized dosing trial of nifedipine, propranolol and their combination

AbstractSeventy-four patients with chronic stable mild angina, mild coronary artery disease (83% had one- or two-vessel disease) and normal left ventricular function were studied to measure the response of treadmill exercise performance and painful and silent ischemia in the ambulatory setting to randomly assigned treatment with nifedipine or propranolol and their combination; titration to maximal tolerated dosages was performed in doubleblind manner.At 3 months both nifedipine and propranolol reduced the weekly angina rate (p < 0.05); during treadmill exercise testing, increases (p < 0.05) were noted in time to angina and total exercise time and decreases in maximal ST depression at the end of exercise. There were no differences between the responses to nifedipine and propranolol and no significant additional changes were seen after another 3 months of therapy. The combination of nifedipine and propranolol reduced the number of patients with angina on exercise treadmill testing from 64% to 38% (p < 0.05).During ambulatory electrocardiographic monitoring before treatment, there were 1.4 ± 2.4 (mean ± SD) episodes/24 h of painful ischemia and a very low silent ischemia frequency: mean 1.1 ± 2.7 episodes/24 h, mean duration 16 ± 25 min/24 h. Treatment with propranolol and nifedipine resulted in reduction of episodes and duration of painful and painless ischemia; approximately 77% of patients were free of all ischemic episodes.It is concluded that patients with chronic stable mild angina have a low incidence of silent ischemia. Nifedipine or propranolol alone, titrated to individualized maximally tolerated dosages, are equally effective in long-term control of painful and painless ischemia, anginal episodes and exercise-induced ischemia. Combination therapy further reduced only exercise-induced angina and maximal exercise-induced ST depression

Transient Cavity Dynamics and Divergence from the Stokes-Einstein Equation in Organic Aerosol

The diffusion of small molecules through viscous matrices formed by large organic molecules is important across a range of domains, including pharmaceutical science, materials chemistry, and atmospheric science, impacting on, for example, the formation of amorphous and crystalline phases. Here we report significant breakdowns in the Stokes–Einstein (SE) equation from measurements of the diffusion of water (spanning 5 decades) and viscosity (spanning 12 decades) in saccharide aerosol droplets. Molecular dynamics simulations show water diffusion is not continuous, but proceeds by discrete hops between transient cavities that arise and dissipate as a result of dynamical fluctuations within the saccharide lattice. The ratio of transient cavity volume to solvent volume increases with size of molecules making up the lattice, increasing divergence from SE predictions. This improved mechanistic understanding of diffusion in viscous matrices explains, for example, why organic compounds equilibrate according to SE predictions and water equilibrates more rapidly in aerosols

Reaction kinetics of muonium with the halogen gases (F2, Cl2, and Br2)

Copyright @ 1989 American Institute of PhysicsBimolecular rate constants for the thermal chemical reactions of muonium (Mu) with the halogen gases—Mu+X2→MuX+X—are reported over the temperature ranges from 500 down to 100, 160, and 200 K for X2=F2,Cl2, and Br2, respectively. The Arrhenius plots for both the chlorine and fluorine reactions show positive activation energies Ea over the whole temperature ranges studied, but which decrease to near zero at low temperature, indicative of the dominant role played by quantum tunneling of the ultralight muonium atom. In the case of Mu+F2, the bimolecular rate constant k(T) is essentially independent of temperature below 150 K, likely the first observation of Wigner threshold tunneling in gas phase (H atom) kinetics. A similar trend is seen in the Mu+Cl2 reaction. The Br2 data exhibit an apparent negative activation energy [Ea=(−0.095±0.020) kcal mol−1], constant over the temperature range of ∼200–400 K, but which decreases at higher temperatures, indicative of a highly attractive potential energy surface. This result is consistent with the energy dependence in the reactive cross section found some years ago in the atomic beam data of Hepburn et al. [J. Chem. Phys. 69, 4311 (1978)]. In comparing the present Mu data with the corresponding H atom kinetic data, it is found that Mu invariably reacts considerably faster than H at all temperatures, but particularly so at low temperatures in the cases of F2 and Cl2. The current transition state calculations of Steckler, Garrett, and Truhlar [Hyperfine Interact. 32, 779 (986)] for Mu+X2 account reasonably well for the rate constants for F2 and Cl2 near room temperature, but their calculated value for Mu+Br2 is much too high. Moreover, these calculations seemingly fail to account for the trend in the Mu+F2 and Mu+Cl2 data toward pronounced quantum tunneling at low temperatures. It is noted that the Mu kinetics provide a crucial test of the accuracy of transition state treatments of tunneling on these early barrier HX2 potential energy surfaces.NSERC (Canada), Donors of the Petroleum Research Fund, administered by the American Chemical Society, for their partial support of this research and the Canada Council

Methicillin-resistant Staphylococcus aureus acquisition in healthcare workers with cystic fibrosis: a retrospective cross-sectional study.

Background People with cystic fibrosis (CF) may work in healthcare settings risking nosocomial pathogen acquisition. The aim of this study was to determine the incidence of methicillin-resistant Staphylococcus aureus (MRSA) infection in adult healthcare workers with CF (HCWcf). Methods Data was collected in this observational study on MRSA acquisition from 405 CF patients attending an adult CF centre in Australia between 2001–2012. Demographic and clinical characteristics were compared between HCWcf and non-HCWcf. A sub-analysis was subsequently performed to compare demographic and clinical characteristics between those patients (HCWcf versus non-HCWcf) that acquired MRSA. We also investigated rates of chronic MRSA infection and the outcome of eradication treatment in HCWcf. Results A higher proportion of HCWcf acquired MRSA [n = 10/21] compared to non-HCWcf [n = 40/255] (P &lt;0.001). The odds of MRSA acquisition were 8.4 (95 % CI, 3.0 – 23.4) times greater in HCWcf than non-HCWcf. HCWcf with MRSA were older (P = 0.02) and had better lung function (P = 0.009), yet hospitalisation rates were similar compared to non-HCWcf with MRSA. Chronic MRSA infection developed in 36/50 CF patients (HCWcf, n = 6; non-HCWcf, n = 30), with eradication therapy achieved in 5/6 (83 %) HCWcf. Conclusions The rate of MRSA incidence was highest in HCWcf and the workplace is a possible source of acquisition. Vocational guidance should include the potential for MRSA acquisition for CF patients considering healthcare professions