Body site colonization in patients with community-associated methicillin-resistant Staphylococcus aureus and other types of S. aureus skin infections

AbstractEfforts to control spread of community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) are often based on eradication of colonization. However, the role of nasal and non-nasal colonization in the pathogenesis of these infections remains poorly understood. Patients with acute S. aureus skin and soft tissue infection (SSTI) were prospectively enrolled. Each subject's nasal, axillary, inguinal and rectal areas were swabbed for S. aureus and epidemiological risk factors were surveyed. Among the 117 patients enrolled, there were 99 patients who had an SSTI and for whom data could be analysed. Sixty-five patients had a CA-MRSA SSTI. Among these patients, MRSA colonization in the nares, axilla, inguinal area and rectum was 25, 6, 11 and 13%, respectively, and 37% overall were MRSA colonized. Most (96%) MRSA colonization was detected using nose and inguinal screening alone. Non-nasal colonization was 25% among CA-MRSA patients, but only 6% among patients with CA-methicillin-susceptible S. aureus (MSSA) or healthcare-associated MRSA or MSSA. These findings suggest that colonization patterns in CA-MRSA infection are distinct from those in non-CA-MRSA S. aureus infections. The relatively high prevalence of non-nasal colonization may play a key role in CA-MRSA transmission and acquisition of infection

CHANDRA Observations of X-ray Jet Structure on kpc to Mpc Scales

With its exquisite spatial resolution of better than 0.5 arcsecond, the Chandra observatory is uniquely capable of resolving and studying the spatial structure of extragalactic X-ray jets on scales of a few to a few hundred kilo-parsec. Our analyses of four recent Chandra images of quasar jets interpret the X-ray emission as inverse Compton scattering of high energy electrons on the cosmic microwave background. We infer that these jets are in bulk relativistic motion, carrying kinetic powers upwards of 10^46 ergs/s to distances of hundreds of kpc, with very high efficiency.Comment: 4 pages, 3 figures, to be published in the proceedings of the Bologna jet workshop, "The Physics of Relativistic Jets in the CHANDRA and XMM Era.

Ethical Issues in Open Source Software

In this essay we argue that the current social and ethical structure in the Open Source Software (OSS) Community stem from its roots in academia. The individual developers experience a level of autonomy similar to that of a faculty member. Furthermore, we assert that the Open Source Software Community\u27s social structure demands benevolent leadership. We argue that it is difficult to pass off low quality open source software as high quality software and that the Open Source development model offers strong accountability. Finally, we argue that Open Source Software introduces ethical challenges for universities and the software development community

Chronic Outpatient Sildenafil Therapy for Pulmonary Hypertension in a Child After Cardiac Surgery

We report the case of a 14-month-old male with d-transposition of the great arteries, ventricular septal defect, and pulmonary hypertension successfully treated with long-term sildenafil following cardiac surgery. To our knowledge, this is the first published report of long-term sildenafil treatment in a child after corrective cardiac surgery

Binge flying: Behavioural addiction and climate change

Recent popular press suggests that ‘binge flying’ constitutes a new site of behavioural addiction. We theoretically appraise and empirically support this proposition through interviews with consumers in Norway and the United Kingdom conducted in 2009. Consistent findings from across two national contexts evidence a growing negative discourse towards frequent short-haul tourist air travel and illustrate strategies of guilt suppression and denial used to span a cognitive dissonance between the short-term personal benefits of tourism and the air travel’s associated long-term consequences for climate change. Tensions between tourism consumption and changing social norms towards acceptable flying practice exemplify how this social group is beginning to (re)frame what constitutes ‘excessive’ holiday flying, despite concomitantly continuing their own frequent air travels

Tundra photosynthesis captured by satellite-observed solar-induced chlorophyll fluorescence

Accurately quantifying the timing and magnitude of respiration and photosynthesis by high‐latitude ecosystems is important for understanding how a warming climate influences global carbon cycling. Data‐driven estimates of photosynthesis across Arctic regions often rely on satellite‐derived enhanced vegetation index (EVI); we find that satellite observations of solar‐induced chlorophyll fluorescence (SIF) provide a more direct proxy for photosynthesis. We model Alaskan tundra CO2 cycling (2012–2014) according to temperature and shortwave radiation and alternately input EVI or SIF to prescribe the annual seasonal cycle of photosynthesis. We find that EVI‐based seasonality indicates spring “green‐up” to occur 9 days prior to SIF‐based estimates, and that SIF‐based estimates agree with aircraft and tower measurements of CO2. Adopting SIF, instead of EVI, for modeling the seasonal cycle of tundra photosynthesis can result in more accurate estimates of growing season duration and net carbon uptake by arctic vegetation

Blindness and encephalopathy caused by Helichrysum argyrosphaerum DC (Compositae) in sheep and cattle

An outbreak of amaurosis and paresis was observed amongst sheep, and occasionally cattle, which had been grazing on pastures consisting mainly of Helichrysum argyrosphaerum DC. A similar syndrome was produced by feeding the suspect plant to sheep, thereby providing proof of its toxicity. Although none of the sheep became blind and only one developed paralysis, typical spongy lesions were detected in the brains and optic fasciculi of all the experimental animals. The lesion had specific predilection sites, such as the white matter around the lateral ventricles, the optic tracts plus chiasm, the pyramidal tracts and the brachium pontis. Enlargement of the optic fasciculi furthermore gave rise to malacia, papilloedema and retinal changes. Some aged sheep developed cataracts approximately 2-3 months after the initial outbreaks of amaurosis had occurred. Circumstantial and histopathological evidence suggests that the cataracts may be due to chronic Helichrysum poisoning, but this could not be confirmed in the present investigation.The articles have been scanned in colour with a HP Scanjet 5590; 300dpi. Adobe Acroabt XI was used to OCR the text and also for the merging and conversion to the final presentation PDF-format

Long-term trends, current status, and transitions of water quality in Chesapeake Bay

Coincident climatic and human effects strongly influence water-quality properties in estuarine-coastal ecosystems around the world. Time-series data for a number of ecosystems reveal high spatio-temporal variability superimposed on secular trends traceable to nutrient over-enrichment. In this paper, we present new analyses of long-term data for Chesapeake Bay directed at several goals: (1) to distinguish trends from spatio-temporal variability imposed by climatic effects; (2) to assess long-term trends of water-quality properties reflecting degradation and recovery; (3) to propose numerical water-quality criteria as targets for restoration; (4) to assess progress toward attainment of these targets. The bay has experienced multiple impairments associated with nutrient over-enrichment since World War II, e.g., low dissolved oxygen (DO), decreased water clarity, and harmful algal blooms (HAB). Anthropogenic eutrophication has been expressed as increased chlorophyll-a (chl-a) driven by accelerated nutrient loading from 1945 to 1980. Management intervention led to decreased loading thereafter, but deleterious symptoms of excess nutrients persist. Climatic effects exemplified by irregular “dry” and “wet” periods in the last 30+ years largely explain high inter-annual variability of water-quality properties, requiring adjustments to resolve long-term trends. Here, we extend these analyses at a finer temporal scale to six decades of chl-a, Secchi depth, and nitrite plus nitrate (NO 2 + NO 3 ) data to support trend analyses and the development of numerical water-quality criteria. The proposed criteria build on a conceptual model emphasizing the need to distinguish climatic and human effects in gauging progress to reverse eutrophication in estuarine-coastal ecosystems

Seasonal to Inter-Annual Variability of Primary Production in Chesapeake Bay: Prospects to Reverse Eutrophication and Change Trophic Classification

Estuarine-coastal ecosystems are rich areas of the global ocean with elevated rates of organic matter production supporting major fisheries. Net and gross primary production (NPP, GPP) are essential properties of these ecosystems, characterized by high spatial, seasonal, and inter-annual variability associated with climatic effects on hydrology. Over 20 years ago, Nixon defined the trophic classification of marine ecosystems based on annual phytoplankton primary production (APPP), with categories ranging from “oligotrophic” to “hypertrophic”. Source data consisting of shipboard measurements of NPP and GPP from 1982 to 2004 for Chesapeake Bay in the mid-Atlantic region of the United States supported estimates of APPP from 300 to 500 g C m−2 yr−1, corresponding to “eutrophic” to “hypertrophic” categories. Here, we developed generalized additive models (GAM) to interpolate the limited spatio-temporal resolution of source data. Principal goals were: (1) to develop predictive models of NPP and GPP calibrated to source data (1982 to 2004); (2) to apply the models to historical (1960s, 1970s) and monitoring (1985 to 2015) data with adjustments for nutrient loadings and climatic effects; (3) to estimate APPP from model predictions of NPP; (4) to test effects of simulated reductions of phytoplankton biomass or nutrient loadings on trophic classification based on APPP. Simulated 40% decreases of euphotic-layer chl-a or TN and NO2 + NO3 loadings led to decreasing APPP sufficient to change trophic classification from “eutrophic’ to “mesotrophic” for oligohaline (OH) and polyhaline (PH) salinity zones, and from “hypertrophic” to “eutrophic” for the mesohaline (MH) salinity zone of the bay. These findings show that improved water quality is attainable with sustained reversal of nutrient over-enrichment sufficient to decrease phytoplankton biomass and APPP

Long-Term Trends of Nutrients and Phytoplankton in Chesapeake Bay

Climate effects on hydrology impart high variability to water-quality properties, including nutrient loadings, concentrations, and phytoplankton biomass as chlorophyll-a (chl-a), in estuarine and coastal ecosystems. Resolving long-term trends of these properties requires that we distinguish climate effects from secular changes reflecting anthropogenic eutrophication. Here, we test the hypothesis that strong climatic contrasts leading to irregular dry and wet periods contribute significantly to interannual variability of mean annual values of water-quality properties using in situ data for Chesapeake Bay. Climate effects are quantified using annual freshwater discharge from the Susquehanna River together with a synoptic climatology for the Chesapeake Bay region based on predominant sea-level pressure patterns. Time series of water-quality properties are analyzed using historical (1945–1983) and recent (1984–2012) data for the bay adjusted for climate effects on hydrology. Contemporary monitoring by the Chesapeake Bay Program (CBP) provides data for a period since mid-1984 that is significantly impacted by anthropogenic eutrophication, while historical data back to 1945 serve as historical context for a period prior to severe impairments. The generalized additive model (GAM) and the generalized additive mixed model (GAMM) are developed for nutrient loadings and concentrations (total nitrogen—TN, nitrate + nitrate—NO2 + NO3) at the Susquehanna River and water-quality properties in the bay proper, including dissolved nutrients (NO2 + NO3, orthophosphate—PO4), chl-a, diffuse light attenuation coefficient (KD (PAR)), and chl-a/TN. Each statistical model consists of a sum of nonlinear functions to generate flow-adjusted time series and compute long-term trends accounting for climate effects on hydrology. We present results identifying successive periods of (1) eutrophication ca. 1945–1980 characterized by approximately doubled TN and NO2 + NO3 loadings, leading to increased chl-a and associated ecosystem impairments, and (2) modest decreases of TN and NO2 + NO3 loadings from 1981 to 2012, signaling a partial reversal of nutrient over-enrichment. Comparison of our findings with long-term trends of water-quality properties for a variety of estuarine and coastal ecosystems around the world reveals that trends for Chesapeake Bay are weaker than for other systems subject to strenuous management efforts, suggesting that more aggressive actions than those undertaken to date will be required to counter anthropogenic eutrophication of this valuable resource