Spectral Index of the Diffuse Radio Background Measured From 100 to 200 MHz

The mean absolute brightness temperature of the diffuse radio background was measured as a function of frequency in a continuous band between 100 and 200 MHz over an effective solid angle of ~pi str at high Galactic latitude. A spectral brightness temperature index of beta = 2.5 +/- 0.1 (alpha_s = 0.5) was derived from the observations, where the error limits are 3-sigma and include estimates of the instrumental systematics. Zenith drift scans with central declinations of -26.5 degrees and spanning right ascensions 0 to 10 hours yielded little variation in the mean spectral index. The mean absolute brightness temperature at 150 MHz was found to reach a minimum of T = 237 +/- 10 K at a right ascension of 2.5 hours. Combining these measurements with those of Haslam et al. 1982 yields a spectral index of beta = 2.52 +/- 0.04 between 150 and 408 MHz.Comment: 8 pages including 7 figures and 4 tables. Accepted by A

Optimal Streaming Algorithms for Submodular Maximization with Cardinality Constraints

We study the problem of maximizing a non-monotone submodular function subject to a cardinality constraint in the streaming model. Our main contributions are two single-pass (semi-)streaming algorithms that use O?(k)?poly(1/?) memory, where k is the size constraint. At the end of the stream, both our algorithms post-process their data structures using any offline algorithm for submodular maximization, and obtain a solution whose approximation guarantee is ?/(1+?)-?, where ? is the approximation of the offline algorithm. If we use an exact (exponential time) post-processing algorithm, this leads to 1/2-? approximation (which is nearly optimal). If we post-process with the algorithm of [Niv Buchbinder and Moran Feldman, 2019], that achieves the state-of-the-art offline approximation guarantee of ? = 0.385, we obtain 0.2779-approximation in polynomial time, improving over the previously best polynomial-time approximation of 0.1715 due to [Feldman et al., 2018]. One of our algorithms is combinatorial and enjoys fast update and overall running times. Our other algorithm is based on the multilinear extension, enjoys an improved space complexity, and can be made deterministic in some settings of interest

Case Report of Rare Mycobacterium Isolated from Mediastinal Abscess

Introduction Mycobacterium arupense, a member of the Mycobacterium terrae complex identified in 2016, rarely causes infections despite isolation from multiple environmental sources, including water, soil and fish tanks.1 Case reports have described tenosynovitis, osteomyelitis and disseminated infection in an immunocompromised host.1-3 Here we describe a case of M. arupense identified in a polymicrobial mediastinal abscess in a pediatric patient subsequently diagnosed with autosomal dominant hyper-IgE syndrome (AD-HIES). Case Description A 4-year-old female with a history of pneumonia, herpetic skin infection, orbital cellulitis, and eczema presented in respiratory distress with concern for pneumonia. Imaging revealed a posterior mediastinal abscess which was drained on Day 3. Blood cultures identified Streptococcus anginosus, and the abscess fluid grew Streptococcus anginosus, Streptococcus mitis/oralis and Candida albicans. An esophagram and esophagogastroduodenoscopy revealed an esophageal sinus opening and fistula draining into the mediastinal abscess. After surgical closure, the fistula recurred, and an esophageal wound vacuum assisted closure (VAC) was placed. On Day 25, the initial acid-fast bacillus (AFB) abscess culture became positive, and ethambutol, rifampin, azithromycin and amikacin were started. The AFB was identified as M. arupense, and treatment was modified to clarithromycin, rifabutin, and ethambutol. Her course was complicated by drug-induced neutropenia and transaminitis. She received in total 61 days of antifungal, 58 days of antibacterial, and 40 days of M. arupense coverage. Due to the atypical infection, immune evaluation was performed and demonstrated low Th17 lymphocytes. Genetic testing detected a heterozygous pathogenic missense variant in STAT3 (c.2141C\u3eT) consistent with AD-HIES. Discussion This is the first case report of M. arupense isolated from a mediastinal abscess. Most M. arupense infections are secondary to direct inoculation injuries with resulting tenosynovitis and osteomyelitis.1,3 It is recognized as a possible respiratory tract colonizer, and therefore must meet clinical and microbiological criteria for diagnosis of NTM pulmonary disease.4,5 Limited susceptibility data has shown 97.5-100% of isolates susceptible to clarithromycin, ethambutol, and rifabutin. 3 Empiric therapy with these three drugs is recommended pending susceptibility data. Treatment duration data is limited but adequate source control is needed as shown here. Evaluation of inborn errors of immunity should be considered in atypical and severe infections, which led to the diagnosis of AD-HIES. AD-HIES due to dominant-negative mutations in STAT3 is characterized by elevated IgE, eczema, connective tissue and skeletal abnormalities, vascular malformations, and recurrent skin and pulmonary infections.6,7 Loss of STAT3 activation and Th17 response underlies our subject’s susceptibility to mycobacterial disease.8https://digitalcommons.unmc.edu/chri_forum/1058/thumbnail.jp

Diabetes, Obesity, and Hypertension May Enhance Associations between Air Pollution and Markers of Systemic Inflammation

Airborne particulate matter (PM) may lead to increased cardiac risk through an inflammatory pathway. Therefore, we investigated associations between ambient PM and markers of systemic inflammation among repeated measures from 44 senior citizens (≥ 60 years of age) and examined susceptibility by conditions linked to chronic inflammation. Mixed models were used to identify associations between concentrations of fine PM [aerodynamic diameter ≤ 2.5 μm (PM2.5)] averaged over 1–7 days and measures of C-reactive protein (CRP), interleukin-6 (IL-6), and white blood cells (WBCs). Effect modification was investigated for diabetes, obesity, hypertension, and elevated mean inflammatory markers. We found positive associations between longer moving averages of PM2.5 and WBCs across all participants, with a 5.5% [95% confidence interval (CI), 0.10 to 11%] increase per interquartile increase (5.4 μg/m3) of PM2.5 averaged over the previous week. PM2.5 and CRP also exhibited positive associations among all individuals for averages longer than 1 day, with the largest associations for persons with diabetes, obesity, and hypertension. For example, an interquartile increase in the 5-day mean PM2.5 (6.1 μg/m3) was associated with a 14% increase in CRP (95% CI, −5.4 to 37%) for all individuals and an 81% (95% CI, 21 to 172%) increase for persons with diabetes, obesity, and hypertension. Persons with diabetes, obesity, and hypertension also exhibited positive associations between PM2.5 and IL-6. Individuals with elevated mean inflammatory markers exhibited enhanced associations with CRP, IL-6, and WBCs. We found modest positive associations between PM2.5 and indicators of systemic inflammation, with larger associations suggested for individuals with diabetes, obesity, hypertension, and elevated mean inflammatory markers

Energy-Efficient Motion Planning for Multi-Modal Hybrid Locomotion

Hybrid locomotion, which combines multiple modalities of locomotion within a single robot, enables robots to carry out complex tasks in diverse environments. This paper presents a novel method for planning multi-modal locomotion trajectories using approximate dynamic programming. We formulate this problem as a shortest-path search through a state-space graph, where the edge cost is assigned as optimal transport cost along each segment. This cost is approximated from batches of offline trajectory optimizations, which allows the complex effects of vehicle under-actuation and dynamic constraints to be approximately captured in a tractable way. Our method is illustrated on a hybrid double-integrator, an amphibious robot, and a flying-driving drone, showing the practicality of the approach

Antibiotic resistance mechanisms inform discovery: identification and characterization of a novel amycolatopsis strain producing ristocetin.

Discovering new antibiotics is a major scientific challenge, made increasingly urgent by the continued development of resistance in bacterial pathogens. A fundamental understanding of the mechanisms of bacterial antibiotic resistance will be vital for the future discovery or design of new, more effective antibiotics. We have exploited our intimate knowledge of the molecular mechanism of glycopeptide antibiotic resistance in the harmless bacterium Streptomyces coelicolor to develop a new two-step cell wall bioactivity screen, which efficiently identified a new actinomycete strain containing a previously uncharacterized glycopeptide biosynthetic gene cluster. The screen first identifies natural product extracts capable of triggering a generalized cell wall stress response and then specifically selects for glycopeptide antibacterials by assaying for the induction of glycopeptide resistance genes. In this study, we established a diverse natural product extract library from actinomycete strains isolated from locations with widely varying climates and ecologies, and we screened them using the novel two-step bioassay system. The bioassay ultimately identified a single strain harboring the previously unidentified biosynthetic gene cluster for the glycopeptide ristocetin, providing a proof of principle for the effectiveness of the screen. This is the first report of the ristocetin biosynthetic gene cluster, which is predicted to include some interesting and previously uncharacterized enzymes. By focusing on screening libraries of microbial extracts, this strategy provides the certainty that identified producer strains are competent for growth and biosynthesis of the detected glycopeptide under laboratory conditions.This work was supported by funding from the Royal Society, UK (516002.K5877/ROG), the Medical Research council, UK (G0700141) and St. John’s College, University of CambridgeThis the the author accepted manuscript. The final version is available from ASM at http://aac.asm.org/content/early/2014/07/09/AAC.03349-14.abstract

Mechanical circulatory support in acute myocardial infarction and cardiogenic shock: Challenges and importance of randomized control trials

BACKGROUND: Acute myocardial infarction (AMI) complicated by cardiogenic shock (CS) is associated with significant morbidity and mortality. METHODS: We provide an overview of previously conducted studies on the use of mechanical circulatory support (MCS) devices in the treatment of AMI-CS and difficulties which may be encountered in conducting such trials in the United States. RESULTS: Well powered randomized control trials are difficult to conduct in a critically ill patient population due to physician preferences, perceived lack of equipoise and challenges obtaining informed consent. CONCLUSIONS: With growth in utilization of MCS devices in patients with AMI-CS, efforts to perform well-powered, randomized control trials must be undertaken