Space Station crew safety alternatives study. Volume 5: Space Station safety plan

The Space Station Safety Plan has been prepared as an adjunct to the subject contract final report, suggesting the tasks and implementation procedures to ensure that threats are addressed and resolution strategy options identified and incorporated into the space station program. The safety program's approach is to realize minimum risk exposure without levying undue design and operational constraints. Safety objectives and risk acceptances are discussed

Heat transport measurements in turbulent rotating Rayleigh-Benard convection

We present experimental heat transport measurements of turbulent Rayleigh-B\'{e}nard convection with rotation about a vertical axis. The fluid, water with Prandtl number ($\sigma$) about 6, was confined in a cell which had a square cross section of 7.3 cm$\times$7.3 cm and a height of 9.4 cm. Heat transport was measured for Rayleigh numbers $2\times 10^5 <$ Ra $< 5\times 10^8$ and Taylor numbers $0 <$ Ta $< 5\times 10^{9}$. We show the variation of normalized heat transport, the Nusselt number, at fixed dimensional rotation rate $\Omega_D$, at fixed Ra varying Ta, at fixed Ta varying Ra, and at fixed Rossby number Ro. The scaling of heat transport in the range $10^7$ to about $10^9$ is roughly 0.29 with a Ro dependent coefficient or equivalently is also well fit by a combination of power laws of the form $a Ra^{1/5} + b Ra^{1/3}$. The range of Ra is not sufficient to differentiate single power law or combined power law scaling. The overall impact of rotation on heat transport in turbulent convection is assessed.Comment: 16 pages, 12 figure

Strukturelle Charakterisierung eines unbekannten Metaboliten von Ciprofloxacin [Structural characterization of an unknown metabolite of ciprofloxacin]

The chemical structure of an unknown metabolite of ciprofloxacin (CAS 85721-33-1) is characterized by means of reversed phase ion pair liquid chromatography, absorption and fluorescence spectroscopy, partition coefficients as well as chemical and enzymatic hydrolytic degradation. A chemical structure of the unknown metabolite is proposed: N-formyl-desethylen-ciprofloxacin. It can be formed as an intermediate in the oxidative degradation of ciprofloxacin via oxociprofloxacin to desethylen-ciprofloxacin, or it may be formed by conjugation of desethylen-ciprofloxacin with formic acid. The amounts found in plasma and urine of patients were in the range of desethylen-ciprofloxacin, i.e. about 1% of the parent compound

Work process-related lead userness as an antecedent of innovative behavior and user innovation in organizations

Recent studies have identified that employees can be lead users of their employing firm's products, and valuable sources of product innovation, residing within organizational boundaries. We extend this line of thought by recognizing that employees can be lead users with regard to internal work processes. We define work process-related lead userness (WPLU) as the extent to which employees experience unsatisfied process-related needs ahead of others, and expect high benefits from solutions to these needs. We hypothesize a positive association with user innovation in the workplace, evidenced by the development of tools, equipment, materials and methods. We test a moderated mediation model delineating how and when WPLU is related to user innovation within organizational boundaries. Drawing on survey data from 104 employees and 13 supervisors in a forensic services organization, we find that WPLU contributes to user innovation via engagement in innovative work behavior, especially when employees have higher self-efficacy (perceived capability to overcome obstacles) and lower job autonomy (situational constraints on the job)

Cell broadening revisited: Results from high-resolution large-eddy simulations of cold air outbreaks

Large-eddy simulations (LES) have been carried out in order to investigate the structure and development of organized mesoscale cellular convection (MCC) during cold air outbreaks (CAOB) and to reevaluate results by Müller and Chlond. Some limitations of this and other earlier LES studies of CAOBs have been removed by using a parallelized model with both a large horizontal domain and a fine grid resolution. These model simulations reveal a hitherto undiscovered insight into the development of MCC. It is shown that MCC with aspect ratios larger than 10 only develop in the presence of diabatic heat sources, that is, latent heat release within the clouds and cloud-top radiative cooling, which confirms results from previous studies. Simulated cells are of closed type. The wind field is seen to be correlated with the liquid water field, and thus, dynamic variables are organized on the mesoscale as well. Updrafts predominantly occur in regions with high liquid water content. Two-dimensional spectral analysis confirms clear peaks at the wavelength of the MCC. The dynamic variables are characterized by an organized conglomeration of randomly distributed up- and downdrafts, where each convective cell can hardly be detected by eye. Whereas scalar variables like temperature and the liquid water path field are characterized by large scales with aspect ratios of 9 to 11, in the vertical velocity field multiple scales are present simultaneously, with small scales having aspect ratios between 1 and 3 contributing most to the total energy, but also large scales correlated with scales seen in the thermodynamic variables. Copyright 2005 American Meteorological Societ

Beyond convergence rates: Exact recovery with Tikhonov regularization with sparsity constraints

The Tikhonov regularization of linear ill-posed problems with an $\ell^1$ penalty is considered. We recall results for linear convergence rates and results on exact recovery of the support. Moreover, we derive conditions for exact support recovery which are especially applicable in the case of ill-posed problems, where other conditions, e.g. based on the so-called coherence or the restricted isometry property are usually not applicable. The obtained results also show that the regularized solutions do not only converge in the $\ell^1$-norm but also in the vector space $\ell^0$ (when considered as the strict inductive limit of the spaces $\R^n$ as $n$ tends to infinity). Additionally, the relations between different conditions for exact support recovery and linear convergence rates are investigated. With an imaging example from digital holography the applicability of the obtained results is illustrated, i.e. that one may check a priori if the experimental setup guarantees exact recovery with Tikhonov regularization with sparsity constraints

Deep neural network or dermatologist?

Deep learning techniques have proven high accuracy for identifying melanoma in digitised dermoscopic images. A strength is that these methods are not constrained by features that are pre-defined by human semantics. A down-side is that it is difficult to understand the rationale of the model predictions and to identify potential failure modes. This is a major barrier to adoption of deep learning in clinical practice. In this paper we ask if two existing local interpretability methods, Grad-CAM and Kernel SHAP, can shed light on convolutional neural networks trained in the context of melanoma detection. Our contributions are (i) we first explore the domain space via a reproducible, end-to-end learning framework that creates a suite of 30 models, all trained on a publicly available data set (HAM10000), (ii) we next explore the reliability of GradCAM and Kernel SHAP in this context via some basic sanity check experiments (iii) finally, we investigate a random selection of models from our suite using GradCAM and Kernel SHAP. We show that despite high accuracy, the models will occasionally assign importance to features that are not relevant to the diagnostic task. We also show that models of similar accuracy will produce different explanations as measured by these methods. This work represents first steps in bridging the gap between model accuracy and interpretability in the domain of skin cancer classification

Pioglitazone Prevents Capillary Rarefaction in Streptozotocin-Diabetic Rats Independently of Glucose Control and Vascular Endothelial Growth Factor Expression

Background/Aims: Reduction of capillary network density occurs early in the development of metabolic syndrome and may be relevant for the precipitation of diabetes. Agonists of the peroxisome proliferator-activated receptor (PPAR)-gamma transcription factor are vasculoprotective, but their capacity for structural preservation of the microcirculation is unclear. Methods: Male Wistar rats were rendered diabetic by streptozotocin and treated with pioglitazone in chow for up to 12 weeks. Capillary density was determined in heart and skeletal muscle after platelet endothelial cell adhesion molecule-1 (PECAM-1) immunostaining. Hallmarks of apoptosis and angiogenesis were determined. Results: Capillary density deteriorated progressively in the presence of hyperglycemia (from 971/mm(2) to 475/mm(2) in quadriceps muscle during 13 weeks). Pioglitazone did not influence plasma glucose, left ventricular weight, or body weight but nearly doubled absolute and relative capillary densities compared to untreated controls (1.2 vs. 0.6 capillaries/myocyte in heart and 1.5 vs. 0.9 capillaries/myocyte in quadriceps muscle) after 13 weeks of diabetes. No antiapoptotic or angiogenic influence of pioglitazone was detected while a reduced expression of hypoxia-inducible factor-3 alpha and PPAR coactivator-1 alpha (PGC-1 alpha) mRNA as well as vascular endothelial growth factor (VEGF) protein possibly occurred as a consequence of improved vascularization. Conclusion: Pioglitazone preserves microvascular structure in diabetes independently of improvements in glycemic control and by a mechanism unrelated to VEGF-mediated angiogenesis. Copyright (C) 2012 S. Karger AG, Base