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Medical procedures and patient care activities may facilitate environmental dissemination of healthcare-associated pathogens such as methicillin-resistant Staphylococcus aureus (MRSA).
Observational cohort study of MRSA-colonized patients to determine the frequency of and risk factors for environmental shedding of MRSA during procedures and care activities in carriers with positive nares and/or wound cultures. Bivariate analyses were performed to identify factors associated with environmental shedding.
A Veterans Affairs hospital.
This study included 75 patients in contact precautions for MRSA colonization or infection.
Of 75 patients in contact precautions for MRSA, 55 (73%) had MRSA in nares and/or wounds and 25 (33%) had positive skin cultures. For the 52 patients with MRSA in nares and/or wounds and at least 1 observed procedure, environmental shedding of MRSA occurred more frequently during procedures and care activities than in the absence of a procedure (59 of 138, 43% vs 8 of 83, 10%; P < .001). During procedures, increased shedding occurred ≤0.9 m versus >0.9 m from the patient (52 of 138, 38% vs 25 of 138, 18%; P = .0004). Contamination occurred frequently on surfaces touched by personnel (12 of 38, 32%) and on portable equipment used for procedures (25 of 101, 25%). By bivariate analysis, the presence of a wound with MRSA was associated with shedding (17 of 29, 59% versus 6 of 23, 26%; P = .04).
Environmental shedding of MRSA occurs frequently during medical procedures and patient care activities. There is a need for effective strategies to disinfect surfaces and equipment after procedures.
We investigated the ecology and paleoecology of testate amoebae in peatlands of the Colombian páramo to assess the use of testate amoebae as paleoenvironmental indicators. Objectives were to (1) identify environmental controls on testate amoebae, (2) develop transfer functions for paleoenvironmental inference, and (3) examine testate amoebae in a Holocene peat core and compare our findings with other proxy records. Results from 96 modern samples indicate that testate amoebae are sensitive to pH and surface moisture, and cross-validation of transfer functions indicates potential for paleoenvironmental applications. Testate amoebae from the Triunfo Peatland in the Central Cordillera provided a proxy record of pH and water-table depth for the late Holocene, and inferred changes were correlated with peat C/N measurements during most of the record. Comparison with a lake-level reconstruction suggests that at least the major testate amoeba–inferred changes were driven by climate. Our work indicates that testate amoebae are useful paleoenvironmental indicators in high-elevation tropical peatlands.
We present a model capable of explaining 200 years of declining fertility, 200 years of rising educational achievement, and a significant baby boom for the United States and twenty other industrialized market countries. We highlight the importance of secularly declining young adult mortality risk for producing secularly declining fertility and a sudden decline in housing costs after the end of the Second World War, but ending by 1970. In addition, we introduce a new puzzle for the profession: Given the magnitude of the Baby Boom, roughly equal to fertility in 1900 for many of these countries, why did schooling of the Baby Boom cohorts not fall to the 1900 level of their predecessors? In fact, not only did it not fall, but the schooling levels of these cohorts are higher than for previous cohorts. Using a quantitative model, we are able to identify the magnitude of the reduction in costs of education necessary to explain this paradoxical increase in schooling. We produce a novel data set on historical education expenditures with over 1,500 observations. We find empirical support for these cost reductions.
To determine the impact of an environmental disinfection intervention on the incidence of healthcare-associated Clostridium difficile infection (CDI).
A multicenter randomized trial.
In total,16 acute-care hospitals in northeastern Ohio participated in the study.
We conducted a 12-month randomized trial to compare standard cleaning to enhanced cleaning that included monitoring of environmental services (EVS) personnel performance with feedback to EVS and infection control staff. We assessed the thoroughness of cleaning based on fluorescent marker removal from high-touch surfaces and the effectiveness of disinfection based on environmental cultures for C. difficile. A linear mixed model was used to compare CDI rates in the intervention and postintervention periods for control and intervention hospitals. The primary outcome was the incidence of healthcare-associated CDI.
Overall, 7 intervention hospitals and 8 control hospitals completed the study. The intervention resulted in significantly increased fluorescent marker removal in CDI and non-CDI rooms and decreased recovery of C. difficile from high-touch surfaces in CDI rooms. However, no reduction was observed in the incidence of healthcare-associated CDI in the intervention hospitals during the intervention and postintervention periods. Moreover, there was no correlation between the percentage of positive cultures after cleaning of CDI or non-CDI rooms and the incidence of healthcare-associated CDI.
An environmental disinfection intervention improved the thoroughness and effectiveness of cleaning but did not reduce the incidence of healthcare-associated CDI. Thus, interventions that focus only on improving cleaning may not be sufficient to control healthcare-associated CDI.
Anxiety disorders are common, and cognitive–behavioural therapy (CBT) is a first-line treatment. Candidate gene studies have suggested a genetic basis to treatment response, but findings have been inconsistent.
To perform the first genome-wide association study (GWAS) of psychological treatment response in children with anxiety disorders (n = 980).
Presence and severity of anxiety was assessed using semi-structured interview at baseline, on completion of treatment (post-treatment), and 3 to 12 months after treatment completion (follow-up). DNA was genotyped using the Illumina Human Core Exome-12v1.0 array. Linear mixed models were used to test associations between genetic variants and response (change in symptom severity) immediately post-treatment and at 6-month follow-up.
No variants passed a genome-wide significance threshold (P=5×10–8) in either analysis. Four variants met criteria for suggestive significance (P<5×10–6) in association with response post-treatment, and three variants in the 6-month follow-up analysis.
This is the first genome-wide therapygenetic study. It suggests no common variants of very high effect underlie response to CBT. Future investigations should maximise power to detect single-variant and polygenic effects by using larger, more homogeneous cohorts.
This paper produces new estimates for white and black mortality and fertility at the state level from 1800(20)–2000. It produces new estimates of black and white schooling for this same period. Using a calibrated model of black and white parents, we fit the time series of black and white fertility and schooling. We then produce estimates of the benefits of equal education opportunity for blacks over the period 1820–2000. For the better part of US history, blacks have suffered from less access to schooling for their children than whites. This paper quantifies the magnitude of this discrimination. Our estimates of the welfare cost of this discrimination prior to the Civil War range between 0.5 and 20 times black wealth, and between 0.5 and 10 times black wealth prior to 1960. Further we find that the Civil Rights era was valued by blacks in the South by between 1% to 2% of wealth. Outside of the South, we find significant costs of discrimination prior to 1960, ranging from 6% to 150% of black wealth. For these divisions from 1960–2000, blacks have attained rough parity in schooling access. The welfare magnitudes are similar to the hypothetical gains to blacks if they had white mortality rates. We show that the model’s black and white human capital series are strongly, positively correlated with state output measures, black and white permanent incomes and black and white earnings.
To determine the effectiveness of a pulsed xenon ultraviolet (PX-UV) disinfection device for reduction in recovery of healthcare-associated pathogens.
Two acute-care hospitals.
We examined the effectiveness of PX-UV for killing of Clostridium difficile spores, methicillin-resistant Staphylococcus aureus (MRSA), and vancomycin-resistant Enterococcus (VRE) on glass carriers and evaluated the impact of pathogen concentration, distance from the device, organic load, and shading from the direct field of radiation on killing efficacy. We compared the effectiveness of PX-UV and ultraviolet-C (UV-C) irradiation, each delivered for 10 minutes at 4 feet. In hospital rooms, the frequency of native pathogen contamination on high-touch surfaces was assessed before and after 10 minutes of PX-UV irradiation.
On carriers, irradiation delivered for 10 minutes at 4 feet from the PX-UV device reduced recovery of C. difficile spores, MRSA, and VRE by 0.55±0.34, 1.85±0.49, and 0.6±0.25 log10 colony-forming units (CFU)/cm2, respectively. Increasing distance from the PX-UV device dramatically reduced killing efficacy, whereas pathogen concentration, organic load, and shading did not. Continuous UV-C achieved significantly greater log10CFU reductions than PX-UV irradiation on glass carriers. On frequently touched surfaces, PX-UV significantly reduced the frequency of positive C. difficile, VRE, and MRSA culture results.
The PX-UV device reduced recovery of MRSA, C. difficile, and VRE on glass carriers and on frequently touched surfaces in hospital rooms with a 10-minute UV exposure time. PX-UV was not more effective than continuous UV-C in reducing pathogen recovery on glass slides, suggesting that both forms of UV have some effectiveness at relatively short exposure times.
We argue that the authors ignore a broad range of possible means of changing behaviour: unintentional change. Most of the behaviours that people seek to change – either in themselves or that are the subject of public health campaigns–are habitual, and hence not necessarily responsive to intentions. An evolutionary approach should take into account all kinds of evolved behavioural responses.
To determine the source of a cluster of Klebsiella oxytoca isolates cultured from peritoneal fluid of 3 patients with cirrhosis on a single day.
Outbreak investigation and before-after study.
A Veterans Affairs medical center.
Epidemiologic investigation, analysis of antimicrobial susceptibility testing results and molecular typing of K. oxytoca isolates with repetitive sequence-based polymerase chain reaction (rep-PCR), review of microbiology laboratory procedures for processing peritoneal fluid cultures, and comparison of peritoneal fluid contamination rates 18 months before and after modification of laboratory procedures for culturing peritoneal fluid.
Each of the peritoneal fluid samples that grew K. oxytoca was inoculated into blood culture bottles by different clinicians at different hospital locations. None of the patients had clinical findings suggestive of peritonitis or elevated polymorphonuclear cell counts in peritoneal fluid (range, 3-25 cells/μL). Molecular typing with rep-PCR demonstrated that the K. oxytoca isolates were genetically related (greater than 95% similarity). Laboratory procedures included the routine addition of a culture medium supplement of yeast extract and dextrose from a multidose vial into blood culture bottles with peritoneal fluid. After discontinuing use of the culture medium supplement, there was a marked reduction in the number of peritoneal fluid cultures deemed as contaminants (14.3% vs 0.9%; P <.001).
A pseudo-outbreak of K. oxytoca peritonitis and high rates of contamination of peritoneal fluid were attributable to contamination of a multidose culture medium supplement. This article highlights the importance of discouraging the use of multidose vials in all clinical settings.
We introduced a long-term care facility (LTCF) infectious disease (ID) consultation service (LID service) that provides on-site consultations to residents of a Veterans Affairs (VA) LTCF. We determined the impact of the LID service on antimicrobial use and Clostridium difficile infections at the LTCF.
A 160-bed VA LTCF.
Systemic antimicrobial use and positive C. difficile tests at the LTCF were compared for the 36 months before and the 18 months after the initiation of the ID consultation service through segmented regression analysis of an interrupted time series.
Relative to that in the preintervention period, total systemic antibiotic administration decreased by 30% (P<.001), with significant reductions in both oral (32%; P<.001) and intravenous (25%; P = .008) agents. The greatest reductions were seen for tetracyclines (64%; P<.001), clindamycin (61%; P<.001), sulfamethoxazole/trimethoprim (38%; P<.001), fluoroquinolones (38%; P<.001), and β lactam/β-lactamase inhibitor combinations (28%; P<.001). The rate of positive C. difficile tests at the LTCF declined in the postintervention period relative to preintervention rates (P = .04).
Implementation of an LTCF ID service led to a significant reduction in total antimicrobial use. Bringing providers with ID expertise to the LTCF represents a new and effective means to achieve antimicrobial stewardship.
Determining the efficacy of using indicator species to predict the spatial location of biodiversity hotspots is one way of maximising the conservation of biodiversity in already threatened habitats. Recent evidence from Europe suggests raptors can play such an indicator role, so we tested this approach with a globally threatened southern hemisphere species, the Black Harrier Circus maurus. We asked if this species, found in South Africa’s mega-diverse Cape Floral Kingdom, breeds in habitat fragments that were more diverse in terms of small mammals, birds and plants than unoccupied fragments of similar size. Renosterveld is a highly fragmented habitat that has lost > 90% of its original extent and remains only on privately-owned lands. Surveys of small mammals, birds and plants undertaken in 20 fragments in the Overberg region, South Africa, revealed nine with breeding harriers and 11 without harriers. Harrier-occupied fragments were associated with a 3.5 fold higher number of bird species and higher small mammal species richness than unoccupied ones. There was a lower abundance of most plants in occupied patches, except for red grass Themeda triandra which is an indicator of pristine renosterveld. Vegetation structure was significantly different, with harriers nesting on patches with taller, more open vegetation. While the diversity trends were not statistically significant, a positive trend between the presence of harriers and higher abundance of red grass – as an indicator of the more pristine state of the patch, suggests that harriers might allow biodiversity managers a heuristic approach for selecting the remaining patches of pristine renosterveld. The need for intensive sampling of several taxa leads to small samples and a lack of clear-cut trends for these top predators as indicators of plant diversity.
In 2003, the American Statistical Association (ASA) funded the Guidelines for Assessment and Instruction in Statistics Education (GAISE) Project College Report . This report makes recommendations for the teaching of statistics. Examining the evolution of enrollment in statistics courses, the report notes that statistics courses now serve much larger numbers of students with a more diverse set of backgrounds, goals, interests, and attitudes. Courses are now offered in a wide variety of departments including business, economics, educational psychology, engineering, mathematics, psychology, sociology, and statistics. The content and teaching of statistics courses have also evolved in response to the availability of technology as well as advancements in statistics as a field of study. Building on recommendations put forth in Cobb , the GAISE report recommends that statistics education (verbatim from p. 1 of ):
Emphasize statistical literacy and develop statistical thinking;
Use real data;
Stress conceptual understanding rather than mere knowledge of procedures;
Foster active learning in the classroom;
Use technology for developing conceptual understanding and analyzing data;
Use assessments to improve and evaluate student learning.
At the same time that the GAISE report was being completed, the authors of this chapter were teaching introductory statistics courses at the University of Oklahoma and had started talking about how useful it would be to have a set of clicker questions for real-time assessment of student understanding.
Most regional watersheds in Europe constitute managed human territories importing large amounts of new reactive nitrogen.
As a consequence, groundwater, surface freshwater and coastal seawater are undergoing severe nitrogen contamination and/or eutrophication problems.
A comprehensive evaluation of net anthropogenic inputs of reactive nitrogen (NANI) through atmospheric deposition, crop N fixation, fertiliser use and import of food and feed has been carried out for all European watersheds. A database on N, P and Si fluxes delivered at the basin outlets has been assembled.
A number of modelling approaches based on either statistical regression analysis or mechanistic description of the processes involved in nitrogen transfer and transformations have been developed for relating N inputs to watersheds to outputs into coastal marine ecosystems.
Key findings/state of knowledge
Throughout Europe, NANI represents 3700 kgN/km²/yr (range, 0–8400 depending on the watershed), i.e. five times the background rate of natural N2 fixation.
A mean of approximately 78% of NANI does not reach the basin outlet, but instead is stored (in soils, sediments or ground water) or eliminated to the atmosphere as reactive N forms or as N2.
N delivery to the European marine coastal zone totals 810 kgN/km²/yr (range, 200–4000 depending on the watershed), about four times the natural background. In areas of limited availability of silica, these inputs cause harmful algal blooms.
Anthropogenic increase of nitrogen in water poses direct threats to human and aquatic ecosystems. High nitrate concentrations in drinking water are dangerous for human health. In aquatic ecosystems the nitrogen enrichment produces eutrophication, which is responsible for toxic algal blooms, water anoxia, fish kills and habitat and biodiversity loss.
The continuous nitrogen export to waters reduces the capacity of aquatic ecosystems to absorb, reorganise and adapt to external stress, increasing their vulnerability to future unexpected natural or climate events.
Key findings/state of knowledge
Nitrogen concentrations in European rivers, lakes, aquifers and coastal waters are high in many regions. In addition nitrate concentrations are increasing in groundwaters, threatening the long term quality of the resource.
In Europe, nitrogen pressures occur over large areas, implying elevated costs for meeting the long-term good chemical and ecological water quality requirements. A significant part of the European population could be potentially exposed to high nitrate values in drinking water if adequate treatments were not in place. Furthermore many of European aquatic ecosystems are eutrophic or at risk of eutrophication.
Nitrogen pressures have reduced biodiversity and damaged the resilience of aquatic ecosystems and continue to pose a threat to the aquatic environment and to the provision of goods and services from the aquatic ecosystems.
Even under favourable land use scenarios the nitrogen export to European waters and seas is likely to remain significant in the near future. The effects of climate change on nitrogen export to water are still uncertain.
The mathematical and physical properties of the Lamb vector divergence are explored. Toward this aim, the instantaneous and mean dynamics of the Lamb vector divergence are examined in several analytic and turbulent flow examples relative to its capacity to identify and characterize spatially localized motions having a distinct capacity to effect a time rate of change of momentum. In this context, the transport equation for the Lamb vector divergence is developed and shown to accurately describe the dynamical mechanisms by which adjacent high- and low-momentum fluid parcels interact to effect a time rate of change of momentum and generate forces such as drag. From this, a transport-equation-based framework is developed that captures the self-sustaining spatiotemporal interactions between coherent motions, e.g. ejections and sweeps in turbulent wall flows, as predicted by the binary source–sink distribution of the Lamb vector divergence. New insight into coherent motion development and evolution is found through the analysis of the Lamb vector divergence.
We present a simple method for estimating regressions based on recursive extensive-form games. Our procedure, which can be implemented in most standard statistical packages, involves sequentially estimating standard logits (or probits) in a manner analogous to backwards induction. We demonstrate that the technique produces consistent parameter estimates and show how to calculate consistent standard errors. To illustrate the method, we replicate Leblang's (2003) study of speculative attacks by financial markets and government responses to these attacks.
In Part I we use the two smallest non-abelian finite simple groups, namely the alternating group A5 and the general linear group L3(2) to define larger permutation groups of degrees 12 and 24, respectively. Specifically, we shall obtain highly symmetric sets of generators for each of the new groups and use these generating sets to deduce the groups' main properties. The first group will turn out to be the Mathieu group M12 of order 12 × 11 × 10 × 9 × 8 = 95 040  and the second the Mathieu group M24 of order 24 × 23 × 22 × 21 × 20 × 16 × 3 = 244 823 040 ; they will be shown to be quintuply transitive on 12 and 24 letters, respectively. These constructions were first described in refs.  and .