Hard-Real-Time Computing Performance in a Cloud Environment

The United States Department of Defense (DoD) is rapidly working with DoD Services to move from multi-year (e.g., 7-10) traditional acquisition programs to a commercial industrybased approach for software development. While commercial technologies and approaches provide an opportunity for rapid fielding of mission capabilities to pace threats, the suitability of commercial technologies to meet hard-real-time requirements within a surface combat system is unclear. This research establishes technical data to validate the effectiveness and suitability of current commercial technologies to meet the hard-real-time demands of a DoD combat management system. (Moreland Jr., 2013) conducted similar research; however, microservices, containers, and container orchestration technologies were not on the DoD radar at the time. Updated knowledge in this area will inform future DoD roadmaps and investments. A mission-based approach using Mission Engineering will be used to set the context for applied research. A hypothetical yet operationally relevant Strait Transit scenario has been established to provide context for definition of experimental parameters to be set while assessing the hypothesis. System models federated to form a system-of-systems architecture and data from a cloud computing environment are used to collect data for quantitative analysis

Landing site considerations for atmosphere structure and meteorology

The goal of the ASI/MET experiments is to extend our knowledge of Mars atmosphere structure and meteorology over that established by the Viking mission. The two in situ soundings of Mars atmosphere by Vikings 1 and 2 were highly similar, but radio occultations and infrared soundings have shown large variability in atmosphere structure on Mars with latitude, season, and terrain elevation. It would be of great interest to obtain an in situ sounding showing strong contrast in thermal structure with the Viking profiles. These would be expected to occur in the winter season, in the southern hemisphere, or at polar latitudes. These options are ruled out by Pathfinder Mission constraints, which place the entry in low, northern latitudes in mid summer, with small seasonal difference from the two Viking landers, and small latitude difference from Viking 1

A Dynamic Model of Demand for Houses and Neighborhoods

We develop a tractable model of neighborhood choice in a dynamic setting along with a computationally straightforward estimation approach. This approach uses information about neighborhood choices and the timing of moves to recover moving costs and preferences for dynamically-evolving housing and neighborhood attributes. The model and estimator are potentially applicable to the study of a wide range of dynamic phenomena in housing markets and cities. We focus here on estimating the marginal willingness to pay for non-marketed amenities – neighborhood racial composition, air pollution, and violent crime – using rich dynamic data. Consistent with the time-series properties of each amenity, we find that a static demand model understates willingness to pay to avoid pollution and crime but overstates willingness to pay to live near neighbors of one’s own race. These findings have important implications for the class of static housing demand models typically used to value urban amenities.

Estimating the Willingness to Pay to Avoid Violent Crime: A Dynamic Approach

The hedonic model, which has been used extensively in the environmental, urban, and real estate literatures, allows for the estimation of the implicit prices of housing and neighborhood attributes (such as square footage, local crime rates, and school quality), as well as households' demand for these nonmarketed amenities. A recognized drawback of the existing hedonic literature is that the models assume a myopic decision maker, i.e., households do not look to the future when choosing where to live today. In this paper, we apply a dynamic hedonic model of demand to estimate the willingness to pay to avoid violent crime. The existing literature, based on Sherwin Rosen's seminal 1974 paper, estimates households' willingness to pay for a given amenity by taking advantage of the first-order conditions for utility maximization, i.e., by requiring that the marginal change in price associated with an increase in amenity consumption will be equal to the marginal utility associated with the increase. Given that these first-order conditions are derived from a myopic utility maximization problem (and not the maximization of a lifetime utility function), the traditional model will yield unbiased estimates only under the assumption that households are not forward-looking when they purchase a house. Considering the substantial transaction costs that are present in the real estate market (both monetary and psychological), this assumption is unlikely to hold in most real-world applications. Bishop and Murphy (2011) expand the existing hedonic framework by allowing households to be forward-looking with respect to the ame

Accuracy of prospective two-dimensional/Doppler echocardiography in the assessment of reparative surgery

Between January 1987 and January 1989, all 129 patients (aged 11 days to 25 years, median 39 months) undergoing both an echocardiographic examination and cardiac catheterization after reparative surgery were prospectively included in a study to assess the accuracy of combined two-dimensional and Doppler color flow imaging. The patient diagnoses were transposition of the great arteries (n = 20), tetralogy of Fallot (n = 38), coarctation of the aorta (n = 24), complete atrioventricular (AV) canal (n = 15), atrial septal defect (n = 8), ventricular septal defects (n = 3), pulmonary stenosis (n = 4), aortic stenosis (n = 8) and subaortic stenosis (n = 9).In arterial tract stenosis, there was high correlation between Doppler estimates and catheterization-derived measurements of residual right ventricular outflow tract obstruction in patients after the arterial switch operation for transposition of the great arteries (r = 0.95) as well as in patients after corrective repair of tetralogy of Fallot (r = 0.84).In semilunar/AV valve regurgitation, graded as none, mild, moderate or severe, echocardiographic estimates correlated exactly with angiographic grading in 84% and differed by one angiographic grade in the other 16%.In residual left to right shunting, no hemodynamically significant shunt was missed by echocardiography. For residual shunts at the ventricular level (n = 32), addition of Doppler color flow imaging improved the sensitivity (from 63% to 94%) and the negative predictive value (from 88% to 98%).In elevated right ventricular pressure, Doppler-derived right ventricular-right atrial pressure estimates in 24 patients correlated well with catheterization measurements (r = 0.93).Combined two-dimensional and Doppler color flow echocardiography was highly accurate in the prospective evaluation of these four types of postoperative residua

Regulation of myogenic progenitor proliferation in human fetal skeletal muscle by BMP4 and its antagonist Gremlin

Skeletal muscle side population (SP) cells are thought to be “stem”-like cells. Despite reports confirming the ability of muscle SP cells to give rise to differentiated progeny in vitro and in vivo, the molecular mechanisms defining their phenotype remain unclear. In this study, gene expression analyses of human fetal skeletal muscle demonstrate that bone morphogenetic protein 4 (BMP4) is highly expressed in SP cells but not in main population (MP) mononuclear muscle-derived cells. Functional studies revealed that BMP4 specifically induces proliferation of BMP receptor 1a–positive MP cells but has no effect on SP cells, which are BMPR1a-negative. In contrast, the BMP4 antagonist Gremlin, specifically up-regulated in MP cells, counteracts the stimulatory effects of BMP4 and inhibits proliferation of BMPR1a-positive muscle cells. In vivo, BMP4-positive cells can be found in the proximity of BMPR1a-positive cells in the interstitial spaces between myofibers. Gremlin is expressed by mature myofibers and interstitial cells, which are separate from BMP4-expressing cells. Together, these studies propose that BMP4 and Gremlin, which are highly expressed by human fetal skeletal muscle SP and MP cells, respectively, are regulators of myogenic progenitor proliferation

The Effect of Macular Hole Duration on Surgical Outcomes: An Individual Participant Data Study of Randomized Controlled Trials

Topic: To define the effect of symptom duration on outcomes in people undergoing surgery for idiopathic full-thickness macular holes (iFTMHs) by means of an individual participant data (IPD) study of randomized controlled trials (RCTs). The outcomes assessed were primary iFTMH closure and postoperative best-corrected visual acuity (BCVA). Clinical Relevance: Idiopathic full-thickness macular holes are visually disabling with a prevalence of up to 0.5%. Untreated BCVA is typically reduced to 20/200. Surgery can close holes and improve vision. Symptom duration is thought to affect outcomes with surgery, but the effect is unclear. Methods: A systematic review identified eligible RCTs that included adults with iFTMH undergoing vitrectomy with gas tamponade in which symptom duration, primary iFTMH closure, and postoperative BCVA were recorded. Bibliographic databases were searched for articles published between 2000 and 2020. Individual participant data were requested from eligible studies. Results: Twenty eligible RCTs were identified. Data were requested from all studies and obtained from 12, representing 940 eyes in total. Median symptom duration was 6 months (interquartile range, 3–10). Primary closure was achieved in 81.5% of eyes. There was a linear relationship between predicted probability of closure and symptom duration. Multilevel logistic regression showed each additional month of duration was associated with 0.965 times lower odds of closure (95% confidence interval [CI], 0.935–0.996, P = 0.026). Internal limiting membrane (ILM) peeling, ILM flap use, better preoperative BCVA, face-down positioning, and smaller iFTMH size were associated with increased odds of primary closure. Median postoperative BCVA in eyes achieving primary closure was 0.48 logarithm of the minimum angle of resolution (logMAR) (20/60). Multilevel logistic regression showed for eyes achieving primary iFTMH closure, each additional month of symptom duration was associated with worsening BCVA by 0.008 logMAR units (95% CI, 0.005–0.011, P < 0.001) (i.e., ∼1 Early Treatment Diabetic Retinopathy Study letter loss per 2 months). ILM flaps, intraocular tamponade using long-acting gas, better preoperative BCVA, smaller iFTMH size, and phakic status were also associated with improved postoperative BCVA. Conclusions: Symptom duration was independently associated with both anatomic and visual outcomes in persons undergoing surgery for iFTMH. Time to surgery should be minimized and care pathways designed to enable this