4,752 research outputs found
Enhancing International Space Station (ISS) Mission Control Center (MCC) Operations Using Tcl/Tk
This paper will discuss the use of Tcl/Tk to enhance the abilities of flight controllers to control the International Space Station (ISS) from the Mission Control Center (MCC) at the Johnson Space Center. We will discuss why existing tools where not able to meet these needs as easily as Tcl/Tk. In addition, we will also discuss how we interfaced with the existing MCC infrastructure to receive ISS telemetry, find servers, register services, and send commands to ISS
Securing circulation pharmaceutically: antiviral stockpiling and pandemic preparedness in the European Union
Governments in Europe and around the world amassed vast pharmaceutical stockpiles in anticipation of a potentially catastrophic influenza pandemic. Yet the comparatively âmildâ course of the 2009 H1N1 pandemic provoked considerable public controversy around those stockpiles, leading to questions about their costâbenefit profile and the commercial interests allegedly shaping their creation, as well as around their scientific evidence base. So, how did governments come to view pharmaceutical stockpiling as such an indispensable element of pandemic preparedness planning? What are the underlying security rationalities that rapidly rendered antivirals such a desirable option for government planners? Drawing upon an in-depth reading of Foucaultâs notion of a âcrisis of circulationâ, this article argues that the rise of pharmaceutical stockpiling across Europe is integral to a governmental rationality of political rule that continuously seeks to anticipate myriad circulatory threats to the welfare of populations â including to their overall levels of health. Novel antiviral medications such as Tamiflu are such an attractive policy option because they could enable governments to rapidly modulate dangerous levels of (viral) circulation during a pandemic, albeit without disrupting all the other circulatory systems crucial for maintaining population welfare. Antiviral stockpiles, in other words, promise nothing less than a pharmaceutical securing of circulation itself
New Experimental Limits on Macroscopic Forces Below 100 Microns
Results of an experimental search for new macroscopic forces with Yukawa
range between 5 and 500 microns are presented. The experiment uses 1 kHz
mechanical oscillators as test masses with a stiff conducting shield between
them to suppress backgrounds. No signal is observed above the instrumental
thermal noise after 22 hours of integration time. These results provide the
strongest limits to date between 10 and 100 microns, improve on previous limits
by as much as three orders of magnitude, and rule out half of the remaining
parameter space for predictions of string-inspired models with low-energy
supersymmetry breaking. New forces of four times gravitational strength or
greater are excluded at the 95% confidence level for interaction ranges between
200 and 500 microns.Comment: 25 Pages, 7 Figures: Minor Correction
Integration of airborne and ground observations of nitryl chloride in the Seoul metropolitan area and the implications on regional oxidation capacity during KORUS-AQ 2016
Nitryl chloride (ClNO2) is a radical reservoir species that releases chlorine radicals upon photolysis. An integrated analysis of the impact of ClNO2 on regional photochemistry in the Seoul metropolitan area (SMA) during the Korea-United States Air Quality Study (KORUS-AQ) 2016 field campaign is presented. Comprehensive multiplatform observations were conducted aboard the NASA DC-8 and at two ground sites (Olympic Park, OP; Taehwa Research Forest, TRF), representing an urbanized area and a forested suburban region, respectively. Positive correlations between daytime Cl2 and ClNO2 were observed at both sites, the slope of which was dependent on O3 levels. The possible mechanisms are explored through box model simulations constrained with observations. The overall diurnal variations in ClNO2 at both sites appeared similar but the nighttime variations were systematically different. For about half of the observation days at the OP site the level of ClNO2 increased at sunset but rapidly decreased at around midnight. On the other hand, high levels were observed throughout the night at the TRF site. Significant levels of ClNO2 were observed at both sites for 4-5 h after sunrise. Airborne observations, box model calculations, and back-trajectory analysis consistently show that these high levels of ClNO2 in the morning are likely from vertical or horizontal transport of air masses from the west. Box model results show that chlorine-radical-initiated chemistry can impact the regional photochemistry by elevating net chemical production rates of ozone by 25% in the morning
Multi-product firms and exporting: a developing country perspective
In this paper we make the distinction between single-product and multi-product firms to contribute to our understanding of the complex relationship between multinational enterprises (MNEs), exporting and economic development. Using firm-level data for Thailand we show that the number of goods produced causes a larger variation in exports volumes than production volumes. Whilst the number of products and the total volume of exports are positively correlated we find, in contrast to US studies, a negative correlation between the number of products produced and the volume of production per product. We then investigate the characteristics associated with multi-product firms and find a distinction between foreign-owned and domestic firms. The presence of foreign firms producing single products solely for the domestic market as well as those producing many products for export demonstrates the diversity of behaviour of foreign-owned firms in developing countries
Galactic and Extragalactic Samples of Supernova Remnants: How They Are Identified and What They Tell Us
Supernova remnants (SNRs) arise from the interaction between the ejecta of a
supernova (SN) explosion and the surrounding circumstellar and interstellar
medium. Some SNRs, mostly nearby SNRs, can be studied in great detail. However,
to understand SNRs as a whole, large samples of SNRs must be assembled and
studied. Here, we describe the radio, optical, and X-ray techniques which have
been used to identify and characterize almost 300 Galactic SNRs and more than
1200 extragalactic SNRs. We then discuss which types of SNRs are being found
and which are not. We examine the degree to which the luminosity functions,
surface-brightness distributions and multi-wavelength comparisons of the
samples can be interpreted to determine the class properties of SNRs and
describe efforts to establish the type of SN explosion associated with a SNR.
We conclude that in order to better understand the class properties of SNRs, it
is more important to study (and obtain additional data on) the SNRs in galaxies
with extant samples at multiple wavelength bands than it is to obtain samples
of SNRs in other galaxiesComment: Final 2016 draft of a chapter in "Handbook of Supernovae" edited by
Athem W. Alsabti and Paul Murdin. Final version available at
https://doi.org/10.1007/978-3-319-20794-0_90-
Biomass burning influence on high-latitude tropospheric ozone and reactive nitrogen in summer 2008: a multi-model analysis based on POLMIP simulations
We have evaluated tropospheric ozone enhancement in air dominated by biomass burning emissions at high latitudes (> 50° N) in July 2008, using 10 global chemical transport model simulations from the POLMIP multi-model comparison exercise. In model air masses dominated by fire emissions, ÎO3/ÎCO values ranged between 0.039 and 0.196 ppbv ppbvâ1 (mean: 0.113 ppbv ppbvâ1) in freshly fire-influenced air, and between 0.140 and 0.261 ppbv ppbvâ1 (mean: 0.193 ppbv) in more aged fire-influenced air. These values are in broad agreement with the range of observational estimates from the literature. Model ÎPAN/ÎCO enhancement ratios show distinct groupings according to the meteorological data used to drive the models. ECMWF-forced models produce larger ÎPAN/ÎCO values (4.47 to 7.00 pptv ppbvâ1) than GEOS5-forced models (1.87 to 3.28 pptv ppbvâ1), which we show is likely linked to differences in efficiency of vertical transport during poleward export from mid-latitude source regions. Simulations of a large plume of biomass burning and anthropogenic emissions exported from towards the Arctic using a Lagrangian chemical transport model show that 4-day net ozone change in the plume is sensitive to differences in plume chemical composition and plume vertical position among the POLMIP models. In particular, Arctic ozone evolution in the plume is highly sensitive to initial concentrations of PAN, as well as oxygenated VOCs (acetone, acetaldehyde), due to their role in producing the peroxyacetyl radical PAN precursor. Vertical displacement is also important due to its effects on the stability of PAN, and subsequent effect on NOx abundance. In plumes where net ozone production is limited, we find that the lifetime of ozone in the plume is sensitive to hydrogen peroxide loading, due to the production of HOx from peroxide photolysis, and the key role of HO2 + O3 in controlling ozone loss. Overall, our results suggest that emissions from biomass burning lead to large-scale photochemical enhancement in high-latitude tropospheric ozone during summer
Rectal Transmission of Transmitted/Founder HIV-1 Is Efficiently Prevented by Topical 1% Tenofovir in BLT Humanized Mice
Rectal microbicides are being developed to prevent new HIV infections in both men and women. We focused our in vivo preclinical efficacy study on rectally-applied tenofovir. BLT humanized mice (nâ=â43) were rectally inoculated with either the primary isolate HIV-1(JRCSF) or the MSM-derived transmitted/founder (T/F) virus HIV-1(THRO) within 30 minutes following treatment with topical 1% tenofovir or vehicle. Under our experimental conditions, in the absence of drug treatment we observed 50% and 60% rectal transmission by HIV-1(JRCSF) and HIV-1(THRO), respectively. Topical tenofovir reduced rectal transmission to 8% (1/12; log rank pâ=â0.03) for HIV-1(JRCSF) and 0% (0/6; log rank pâ=â0.02) for HIV-1(THRO). This is the first demonstration that any human T/F HIV-1 rectally infects humanized mice and that transmission of the T/F virus can be efficiently blocked by rectally applied 1% tenofovir. These results obtained in BLT mice, along with recent ex vivo, Phase 1 trial and non-human primate reports, provide a critically important step forward in the development of tenofovir-based rectal microbicides
Observational cohort study with internal and external validation of a predictive tool for identification of children in need of hospital admission from the emergency department : the Paediatric Admission Guidance in the Emergency department (PAGE) score
Objectives: To devise an assessment tool to aid discharge and admission decision making in relation to children and young people in hospital urgent and emergency
care facilities, and thereby improve the quality of care that patients receive, using a
clinical prediction modelling approach
Design: Observational cohort study with internal and external validation of a
predictive tool
Setting: Two general emergency departments and an urgent care centre in the
North of England.
Participants: The eligibility criteria were children and young people 0-16 years of
age who attended one of the three hospital sites within one NHS Trust. Children
were excluded if they opted out of the study, were brought to the emergency
department (ED) following their death in the community, or arrived in cardiac arrest
when the heart rate and respiratory rate would be unmeasurable.
Main outcome measures: Admission or discharge. A participant was defined as
being admitted to hospital if they left the ED to enter the hospital for further
assessment, (including being admitted to an observation and assessment unit or
hospital ward), either on first presentation or with the same complaint within seven
days. Those who were not admitted were defined as having been discharged.
Results: The study collected data on 36365 participants. 15328 participants were
included in the final analysis cohort (21045 observations) and 17710 participants
were included in the validation cohort (23262 observations). There were 14 variables
entered into the regression analysis. Of the 13 that remained in the final model, 10
were present in all 500 bootstraps. The resulting
Paediatric Admission Guidance in the Emergency department (PAGE) score demonstrated good internal validity. The
C-index (AUROC) was 0.779 (95% CI 0.772 to 0.786).
Conclusions: For units without the immediate availability of paediatricians the
PAGE score can assist staff to determine risk of admission. Cut off values will need
to be adjusted to local circumstance
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