On the galloping instability of two-dimensional bodies having elliptical cross sections.

Galloping, also known as Den Hartog instability, is the large amplitude, low frequency oscillation of a structure in the direction transverse to the mean wind direction. It normally appears in the case of bodies with small stiffness and structural damping, when they are placed in a flow provided the incident velocity is high enough. Galloping depends on the slope of the lift coefficient versus angle of attack curve, which must be negative. Generally speaking this implies that the body is stalled after boundary layer separation, which, as it is known in non-wedged bodies, is a Reynolds number dependent phenomenon. Wind tunnel experiments have been conducted aiming at establishing the characteristics of the galloping motion of elliptical cross-section bodies when subjected to a uniform flow, the angles of attack ranging from 0° to 90°. The results have been summarized in stability maps, both in the angle of attack versus relative thickness and in the angle of attack versus Reynolds number planes, where galloping instability regions are identified

BLITZEN: A highly integrated massively parallel machine

The architecture and VLSI design of a new massively parallel processing array chip are described. The BLITZEN processing element array chip, which contains 1.1 million transistors, serves as the basis for a highly integrated, miniaturized, high-performance, massively parallel machine that is currently under development. Each processing element has 1K bits of static RAM and performs bit-serial processing with functional elements for arithmetic, logic, and shifting

Cultural health assets of Somali and Oromo refugees and immigrants in Minnesota: Findings from a community-based participatory research project

This community-based participatory research study sought to identify the cultural health assets of the Somali and Oromo communities in one Minnesota neighborhood that could be mobilized to develop culturally appropriate health interventions. Community asset mappers conducted 76 interviews with Somali and Oromo refugees in in Minnesota regarding the cultural assets of their community. A community-university data analysis team coded data for major themes. Key cultural health assets of the Somali and Oromo refugee communities revealed in this study include religion and religious beliefs, religious and cultural practices, a strong culture of sharing, interconnectedness, the prominence of oral traditions, traditional healthy eating and healthy lifestyles, traditional foods and medicine, and a strong cultural value placed on health. These cultural health assets can be used as building blocks for culturally relevant health interventions.published_or_final_versio

INSPACE CHEMICAL PROPULSION SYSTEMS AT NASA's MARSHALL SPACE FLIGHT CENTER: HERITAGE AND CAPABILITIES

NASA s Marshall Space Flight Center (MSFC) is well known for its contributions to large ascent propulsion systems such as the Saturn V rocket and the Space Shuttle external tank, solid rocket boosters, and main engines. This paper highlights a lesser known but very rich side of MSFC-its heritage in the development of in-space chemical propulsion systems and its current capabilities for spacecraft propulsion system development and chemical propulsion research. The historical narrative describes the flight development activities associated with upper stage main propulsion systems such as the Saturn S-IVB as well as orbital maneuvering and reaction control systems such as the S-IVB auxiliary propulsion system, the Skylab thruster attitude control system, and many more recent activities such as Chandra, the Demonstration of Automated Rendezvous Technology (DART), X-37, the X-38 de-orbit propulsion system, the Interim Control Module, the US Propulsion Module, and multiple technology development activities. This paper also highlights MSFC s advanced chemical propulsion research capabilities, including an overview of the center s Propulsion Systems Department and ongoing activities. The authors highlight near-term and long-term technology challenges to which MSFC research and system development competencies are relevant. This paper concludes by assessing the value of the full range of aforementioned activities, strengths, and capabilities in light of NASA s exploration missions

Increased systemic inflammation is associated with cardiac and vascular dysfunction over the first 12 weeks of antiretroviral therapy among undernourished, HIV-infected adults in Southern Africa.

This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.INTRODUCTION: Persistent systemic inflammation is associated with mortality among undernourished, HIV-infected adults starting antiretroviral therapy (ART) in sub-Saharan Africa, but the etiology of these deaths is not well understood. We hypothesized that greater systemic inflammation is accompanied by cardiovascular dysfunction over the first 12 weeks of ART. METHODS: In a prospective cohort of 33 undernourished (body mass index <18.5 kg/m2) Zambian adults starting ART, we measured C-reactive protein (CRP), tumor necrosis factor-α receptor 1 (TNF-α R1), and soluble CD163 and CD14 at baseline and 12 weeks. An EndoPAT device measured the reactive hyperemia index (LnRHI; a measure of endothelial responsiveness), peripheral augmentation index (AI; a measure of arterial stiffness), and heart rate variability (HRV; a general marker of autonomic tone and cardiovascular health) at the same time points. We assessed paired changes in inflammation and cardiovascular parameters, and relationships independent of time point (adjusted for age, sex, and CD4+ T-cell count) using linear mixed models. RESULTS: Serum CRP decreased (median change -3.5 mg/l, p=0.02), as did TNF-α R1 (-0.31 ng/ml, p<0.01), over the first 12 weeks of ART. A reduction in TNF-α R1 over 12 weeks was associated with an increase in LnRHI (p=0.03), and a similar inverse relationship was observed for CRP and LnRHI (p=0.07). AI increased in the cohort as a whole over 12 weeks, and a reduction in sCD163 was associated with a rise in the AI score (p=0.04). In the pooled analysis of baseline and 12 week data, high CRP was associated with lower HRV parameters (RMSSD, p=0.01; triangular index, p<0.01), and higher TNF- α R1 accompanied lower HRV (RMSSD, p=0.07; triangular index, p=0.06). CONCLUSIONS: Persistent inflammation was associated with impaired cardiovascular health over the first 12 weeks of HIV treatment among undernourished adults in Africa, suggesting cardiac events may contribute to high mortality in this population.This work was supported by the Vanderbilt Meharry Center for AIDS Research (NIH grant number P30 AI54999); the NIH Fogarty International Center, Office of the Director, National Institutes of Health, National Heart, Blood, and Lung Institute, and National Institute of Mental Health, through the Vanderbilt-Emory-Cornell-Duke Consortium for Global Health Fellows (grant number R25 TW009337); the National Center for Advancing Translational Sciences (CTSA award number UL1TR000445) and the European and Developing Countries Clinical Trials Partnership (grant IP.2009.33011.004)

Bimodality In Interim Reports: An Analysts' View

Cumulative abnormal residuals (cars) show how markets adjust to published information. Theoretically, cars are assumed to display unit normal behavior.&nbsp; Despite its merits, car has proved to be a somewhat imprecise measure of market response to published information.&nbsp; In practice, cars exhibit considerable deviation from theoretical unit normal behavior. Three disparities between theory and practice can be pinpointed.&nbsp; These are car: (1) location, (2) shape, and (3) stability.&nbsp; In our previous work we have demonstrated that cars are often bimodally distributed.&nbsp; This finding shows one reason why it takes semistrong efficient markets some time to digest new information. Cars, for the time period during which markets analyze the new value determining data, are usually bimodally distributed. One mode of the distribution represents the impact of good news. The other peak is caused by bad news.&nbsp; The valley, between the two peaks, indicates the influence of neutral news. &nbsp;This paper analyzes the interim reports, which constitute the data for our previous related studies. This research identifies the type of new information that creates bimodal cars

Interaction of reed and acoustic resonator in clarinetlike systems

Sound emergence in clarinetlike instruments is investigated in terms of instability of the static regime. Various models of reed-bore coupling are considered, from the pioneering work of Wilson and Beavers ["Operating modes of the clarinet", J. Acoust. Soc. Am. 56, 653--658 (1974)] to more recent modeling including viscothermal bore losses and vena contracta at the reed inlet. The pressure threshold above which these models may oscillate as well as the frequency of oscillation at threshold are calculated. In addition to Wilson and Beavers' previous conclusions concerning the role of the reed damping in the selection of the register the instrument will play on, the influence of the reed motion induced flow is also emphasized, particularly its effect on playing frequencies, contributing to reduce discrepancies between Wilson and Beavers' experimental results and theory, despite discrepancies still remain concerning the pressure threshold. Finally, analytical approximations of the oscillating solution based on Fourier series expansion are obtained in the vicinity of the threshold of oscillation. This allows to emphasize the conditions which determine the nature of the bifurcation (direct or inverse) through which the note may emerge, with therefore important consequences on the musical playing performances

Incidence and Outcomes Associated With Clostridium difficile Infections: A Systematic Review and Meta-analysis

Importance: An understanding of the incidence and outcomes of Clostridium difficile infection (CDI) in the United States can inform investments in prevention and treatment interventions. Objective: To quantify the incidence of CDI and its associated hospital length of stay (LOS) in the United States using a systematic literature review and meta-analysis. Data Sources: MEDLINE via Ovid, Cochrane Library Databases via Wiley, Cumulative Index of Nursing and Allied Health Complete via EBSCO Information Services, Scopus, and Web of Science were searched for studies published in the United States between 2000 and 2019 that evaluated CDI and its associated LOS. Study Selection: Incidence data were collected only from multicenter studies that had at least 5 sites. The LOS studies were included only if they assessed postinfection LOS or used methods accounting for time to infection using a multistate model or compared propensity score-matched patients with CDI with control patients without CDI. Long-term-care facility studies were excluded. Of the 119 full-text articles, 86 studies (72.3%) met the selection criteria. Data Extraction and Synthesis: Two independent reviewers performed the data abstraction and quality assessment. Incidence data were pooled only when the denominators used the same units (eg, patient-days). These data were pooled by summing the number of hospital-onset CDI incident cases and the denominators across studies. Random-effects models were used to obtain pooled mean differences. Heterogeneity was assessed using the I2 value. Data analysis was performed in February 2019. Main Outcomes and Measures: Incidence of CDI and CDI-associated hospital LOS in the United States. Results: When the 13 studies that evaluated incidence data in patient-days due to hospital-onset CDI were pooled, the CDI incidence rate was 8.3 cases per 10 000 patient-days. Among propensity score-matched studies (16 of 20 studies), the CDI-associated mean difference in LOS (in days) between patients with and without CDI varied from 3.0 days (95% CI, 1.44-4.63 days) to 21.6 days (95% CI, 19.29-23.90 days). Conclusions and Relevance: Pooled estimates from currently available literature suggest that CDI is associated with a large burden on the health care system. However, these estimates should be interpreted with caution because higher-quality studies should be completed to guide future evaluations of CDI prevention and treatment interventions

Providing Evidence about the Pandemic: Librarian Roles on a Rapid Response Team for COVID-19

This was presented at the 2021 Medical Library Association Annual Meeting [virtual].BACKGROUND: SARS-CoV-2 has led to a deluge of information. Health leaders/personnel need curated and synthesized information to aid their decision making regarding diagnosis, treatment, mitigation, reopening plans, etc. A collaboration involving the state department of health has been developed to respond to those needs. Several programs were created simultaneously, two of which depend on active librarian involvement. One focuses on rapid expert responses to questions from state leadership supported by annotated bibliographies. The other is a daily digest of emerging literature including reviews on patient care, law and ethics, communication, forecasting and surveillance, schools, and mitigation. DESCRIPTION: Librarians from several libraries at a university are responding to the need for synthesized high-quality information related to the pandemic. These librarians have expertise in the areas of evidence-based medicine, data management, public health, and law. From the beginning, librarians have been heavily involved in creating workflows related to project and data management. Project management included having a standard process for tracking questions, delivering information, and team development. Librarians developed the team through onboarding, defining roles, scheduling, consistent communication, and shared document templates. Librarians created data management processes such as citation management, readme files, file management/naming conventions, data backup, etc. Librarians encouraged adoption of creative commons license notices on public-facing work to make the information more accessible. Project assessment was built into workflows and includes tracking: questions, turn around time, updates, and return on investment. CONCLUSION: Since the inception of this program, librarians have answered over 108 questions and provided 18 updates to annotated bibliographies. The average turnaround time for creating annotated bibliographies is 16 hours with a range of 2-48 hours. In addition, librarians have provided searches to support over 900 blog posts for WISE Indiana. While the pandemic has been stressful, this project provided us with an outlet to support our state. In addition, this project has led to: increased visibility for librarians, salary savings for the library, and recognition for our contributions that led to the receipt of an Award for Excellence in Public Health from Dr. Kristina Box​, the State Health Commissioner for Indiana

microRNAs regulate cell-to-cell variability of endogenous target gene expression in developing mouse thymocytes

The development and homeostasis of multicellular organisms relies on gene regulation within individual constituent cells. Gene regulatory circuits that increase the robustness of gene expression frequently incorporate microRNAs as post-transcriptional regulators. Computational approaches, synthetic gene circuits and observations in model organisms predict that the co-regulation of microRNAs and their target mRNAs can reduce cell-to-cell variability in the expression of target genes. However, whether microRNAs directly regulate variability of endogenous gene expression remains to be tested in mammalian cells. Here we use quantitative flow cytometry to show that microRNAs impact on cell-to-cell variability of protein expression in developing mouse thymocytes. We find two distinct mechanisms that control variation in the activation-induced expression of the microRNA target CD69. First, the expression of miR-17 and miR-20a, two members of the miR-17-92 cluster, is coregulated with the target mRNA Cd69 to form an activation-induced incoherent feed-forward loop. Another microRNA, miR-181a, acts at least in part upstream of the target mRNA Cd69 to modulate cellular responses to activation. The ability of microRNAs to render gene expression more uniform across mammalian cell populations may be important for normal development and for disease