Proposal for modifying the empirical equations of soil displacement for ground shock from buried explosions

This paper studies the empirical equations for predicting soil displacement from ground shock generated by buried or ground penetrating explosive charges. These equations were derived in the 1980s by Drake et al. (1983/1989) and then used in the conventional weapon loads software, TM 5-855-1, developed by US Army Research Engineers. AUTODYN simulations with a one-dimensional finite element wedge were conducted using a multi-material Euler formulation. Different sizes of explosive charges were simulated and the maximum soil displacement in dry sand was studied at different scaled distances Z. When comparing the results from AUTODYN simulations and empirical calculations on maximum soil displacement for charges varying from 0.125 kg to 512 kg in TNT weight and scaled distance Z for each charge from 0.1 to 17 m/kg1/3, AUTODYN simulations indicate that the empirical equations are conservative. Here, the soil model for dry sand from Sj\uf6bo was used in the AUTODYN simulations and compared with dry sand parameters in empirical calculations. The Sj\uf6bo sand’s mechanical properties, including the equation of state (EOS), have been characterized from tri-axial tests performed by Norwegian Geotechnical Institute (NGI) in 2000. When comparing the results in a log-log plot, with axes representing scaled distance and maximum soil displacement, it is seen that the results differ consistently. A proposal is made for scaled distances larger than 1 m/kg1/3\ua0of how the empirical equation for maximum displacement proposed by Drake et al. in 1989 can be modified with a modified scaling factor to receive a better fit with AUTODYN. For smaller scaled distance of less than 0.2 m/kg1/3, the AUTODYN simulations show a saturation shape in the log-log plot. To receive an improved fit with the otherwise straight lines (one line for each charge size), which the original empirical equation was designed with, it is proposed to introduce an exponential factor that saturates the maximum displacements towards a smaller Z

Antibiotics for gastroenteritis in general practice and out-of-hours services in Norway 2006-15

Background When patients with gastroenteritis (GE) seek health care, they are generally managed in primary care. Little is known about the use of antibiotic treatment in these cases. Objective The aim of this study was to investigate time trends and patient characteristics associated with antibiotic treatment for GE in Norwegian primary care in a 10-year period. Methods We linked data from two nationwide registries, reimbursement claims data from Norwegian primary care (the KUHR database) and The Norwegian Prescription Database, for the period 2006–15. GE consultations were extracted, and courses of systemic antibiotics dispensed within 1 day were included for further analyses. Results Antibiotic treatment was linked to 1.8% (n = 23 663) of the 1 279 867 consultations for GE in Norwegian primary care in the period 2006–15. The proportion of GE consultations with antibiotic treatment increased from 1.4% in 2006 to 2.2% in 2012 and then decreased to 1.8% in 2015. Fluoroquinolones (28.9%) and metronidazole (26.8%) were most frequently used. Whereas the number of fluoroquinolones courses decreased after 2012, the number of metronidazole courses continued to increase until year 2015. The antibiotic treatment proportion of GE consultations was lowest in young children and increased with increasing age. Conclusion Antibiotic treatment is infrequently used in GE consultations in Norwegian primary care. Although there was an overall increase in use during the study period, we observed a reduction in overall use after year 2012. Young children were treated with antibiotics in GE consultations less frequent than older patients.publishedVersio

PHAT Stellar Cluster Survey I. Year 1 Catalog and Integrated Photometry

The Panchromatic Hubble Andromeda Treasury (PHAT) survey is an on-going Hubble Space Telescope (HST) multi-cycle program to obtain high spatial resolution imaging of one-third of the M31 disk at ultraviolet through near-infrared wavelengths. In this paper, we present the first installment of the PHAT stellar cluster catalog. When completed, the PHAT cluster catalog will be among the largest and most comprehensive surveys of resolved star clusters in any galaxy. The exquisite spatial resolution achieved with HST has allowed us to identify hundreds of new clusters that were previously inaccessible with existing ground-based surveys. We identify 601 clusters in the Year 1 sample, representing more than a factor of four increase over previous catalogs within the current survey area (390 arcmin^2). This work presents results derived from the first \sim25% of the survey data; we estimate that the final sample will include \sim2500 clusters. For the Year 1 objects, we present a catalog with positions, radii, and six-band integrated photometry. Along with a general characterization of the cluster luminosities and colors, we discuss the cluster luminosity function, the cluster size distributions, and highlight a number of individually interesting clusters found in the Year 1 search.Comment: 26 pages, 22 figures, Accepted by Ap

Macrophages sense and kill bacteria through carbon monoxide-dependent inflammasome activation

Microbial clearance by eukaryotes relies on complex and coordinated processes that remain poorly understood. The gasotransmitter carbon monoxide (CO) is generated by the stress-responsive enzyme heme oxygenase-1 (HO-1, encoded by Hmox1), which is highly induced in macrophages in response to bacterial infection. HO-1 deficiency results in inadequate pathogen clearance, exaggerated tissue damage, and increased mortality. Here, we determined that macrophage-generated CO promotes ATP production and release by bacteria, which then activates the Nacht, LRR, and PYD domains-containing protein 3 (NALP3) inflammasome, intensifying bacterial killing. Bacterial killing defects in HO-1-deficient murine macrophages were restored by administration of CO. Moreover, increased CO levels enhanced the bacterial clearance capacity of human macrophages and WT murine macrophages. CO-dependent bacterial clearance required the NALP3 inflammasome, as CO did not increase bacterial killing in macrophages isolated from NALP3-deficient or caspase-1-deficient mice. IL-1β cleavage and secretion were impaired in HO-1-deficient macrophages, and CO-dependent processing of IL-1β required the presence of bacteria-derived ATP. We found that bacteria remained viable to generate and release ATP in response to CO. The ATP then bound to macrophage nucleotide P2 receptors, resulting in activation of the NALP3/IL-1β inflammasome to amplify bacterial phagocytosis by macrophages. Taken together, our results indicate that macrophage-derived CO permits efficient and coordinated regulation of the host innate response to invading microbes.NIH grants: (HL-071797, HL-076167, HL-106227), American Heart Association grants: (10SDG2640091 and NIH R21CA169904-01), Julie Henry Fund, Transplant Center of the BIDMC, FCT grants: (SFRH/BPD/25436/2005, PTDC/BIO/70815/2006, PTDC/BIA-BCM/101311/2008, PTDC/SAU-FCF/100762/2008), the European Community, 6th Framework grant LSH-2005-1.2.5-1 and ERC-2011-AdG, Howard Hughes Medical Institute

A road to reality with topological superconductors

Topological states of matter are a source of low-energy quasiparticles, bound to a defect or propagating along the surface. In a superconductor these are Majorana fermions, described by a real rather than a complex wave function. The absence of complex phase factors promises protection against decoherence in quantum computations based on topological superconductivity. This is a tutorial style introduction written for a Nature Physics focus issue on topological matter.Comment: pre-copy-editing, author-produced version of the published paper: 4 pages, 2 figure

Theta Activity in the Left Dorsal Premotor Cortex During Action Re-Evaluation and Motor Reprogramming

The ability to rapidly adjust our actions to changes in the environment is a key function of human motor control. Previous work implicated the dorsal premotor cortex (dPMC) in the up-dating of action plans based on environmental cues. Here we used electroencephalography (EEG) to identify neural signatures of up-dating cue-action relationships in the dPMC and connected frontoparietal areas. Ten healthy subjects performed a pre-cued alternate choice task. Simple geometric shapes cued button presses with the right or left index finger. The shapes of the pre-cue and go-cue differed in two third of trials. In these incongruent trials, the go-cue prompted a re-evaluation of the pre-cued action plan, slowing response time relative to trials with identical cues. This re-evaluation selectively increased theta band activity without modifying activity in alpha and beta band. Source-based analysis revealed a widespread theta increase in dorsal and mesial frontoparietal areas, including dPMC, supplementary motor area (SMA), primary motor and posterior parietal cortices (PPC). Theta activity scaled positively with response slowing and increased more strongly when the pre-cue was invalid and required subjects to select the alternate response. Together, the results indicate that theta activity in dPMC and connected frontoparietal areas is involved in the re-adjustment of cue-induced action tendencies

No apparent transmission of livestock-associated methicillin-resistant Staphylococcus aureus CC398 in a survey of staff at a regional Danish hospital

Abstract Background In recent years, livestock-associated methicillin-resistant Staphylococcus aureus (LA-MRSA) multi locus sequence type CC398 has spread widely in the livestock production in Europe. The rates of LA-MRSA in hospitals have been found to be largely determined by contact to and density of livestock in the area. Methods This is a cross sectional study of the prevalence of LA-MRSA among hospital staff in a Danish hospital situated in a livestock production region. We analysed nasal swabs, air and dust samples for the presence of MRSA using PCR and mass spectrometry. Results Of 1745 employees, 545 (31%) contributed nasal swabs. MRSA was not detected in any participant, nor was it detected in air or dust at the hospital or in houses of employees living on farms. Four percent of the participants had contact to pigs either directly or through household members. LA-MRSA was detected in two of 26 samples from animal sheds, both of them from pig farms. The participation rate was relatively low, but participants were representative for the source population with regards to animal contact and job titles. Conclusions The study suggests a low point prevalence of LA-MRSA carriage in Danish hospital staff even in regions where livestock production is dense. Should more studies confirm our findings we see no need for additional hospital precautions towards LA-MRSA in Denmark at the moment. We think that our data might reduce potential stigmatization of hospital workers with contact to LA-MRSA positive farms at their work places and in their communities