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This article investigates whether residents of Mexico City value air quality. Our results suggest that air quality improvement in PM10 is equivalent to a marginal willingness to pay (MWTP) of US$440.31 per property for the period 2006–2013. The corresponding MWTP for PM2.5 is US$880.63, for O3 is US$623.78, and for SO2 is as much as US$2091.50. These estimates are considerably larger in magnitude compared to the few other studies in similar settings. As a percentage of annual household income, these represent 2.44 per cent for PM10, 4.88 per cent for PM2.5, 3.46 per cent for O3 and 11.59 per cent for SO2. Our estimates of land value–pollution elasticities for PM10 (−0.26 and − 0.58) are within range of hedonic estimates for total suspended particulate matter in US cities around the 1970s. The corresponding elasticities range from − 0.55 to − 0.84 for PM2.5, from − 0.06 to − 0.49 for O3 and from − 0.11 to − 0.34 for SO2.
The role that vitamin D plays in pulmonary function remains uncertain. Epidemiological studies reported mixed findings for serum 25-hydroxyvitamin D (25(OH)D)–pulmonary function association. We conducted the largest cross-sectional meta-analysis of the 25(OH)D–pulmonary function association to date, based on nine European ancestry (EA) cohorts (n 22 838) and five African ancestry (AA) cohorts (n 4290) in the Cohorts for Heart and Aging Research in Genomic Epidemiology Consortium. Data were analysed using linear models by cohort and ancestry. Effect modification by smoking status (current/former/never) was tested. Results were combined using fixed-effects meta-analysis. Mean serum 25(OH)D was 68 (sd 29) nmol/l for EA and 49 (sd 21) nmol/l for AA. For each 1 nmol/l higher 25(OH)D, forced expiratory volume in the 1st second (FEV1) was higher by 1·1 ml in EA (95 % CI 0·9, 1·3; P<0·0001) and 1·8 ml (95 % CI 1·1, 2·5; P<0·0001) in AA (Prace difference=0·06), and forced vital capacity (FVC) was higher by 1·3 ml in EA (95 % CI 1·0, 1·6; P<0·0001) and 1·5 ml (95 % CI 0·8, 2·3; P=0·0001) in AA (Prace difference=0·56). Among EA, the 25(OH)D–FVC association was stronger in smokers: per 1 nmol/l higher 25(OH)D, FVC was higher by 1·7 ml (95 % CI 1·1, 2·3) for current smokers and 1·7 ml (95 % CI 1·2, 2·1) for former smokers, compared with 0·8 ml (95 % CI 0·4, 1·2) for never smokers. In summary, the 25(OH)D associations with FEV1 and FVC were positive in both ancestries. In EA, a stronger association was observed for smokers compared with never smokers, which supports the importance of vitamin D in vulnerable populations.
The hard-core model has attracted much attention across several disciplines, representing lattice gases in statistical physics and independent sets in discrete mathematics and computer science. On finite graphs, we are given a parameter λ, and an independent set I arises with probability proportional to λ|I|. On infinite graphs a Gibbs measure is defined as a suitable limit with the correct conditional probabilities, and we are interested in determining when this limit is unique and when there is phase coexistence, i.e., existence of multiple Gibbs measures.
It has long been conjectured that on ℤ2 this model has a critical value λc ≈ 3.796 with the property that if λ < λc then it exhibits uniqueness of phase, while if λ > λc then there is phase coexistence. Much of the work to date on this problem has focused on the regime of uniqueness, with the state of the art being recent work of Sinclair, Srivastava, Štefankovič and Yin showing that there is a unique Gibbs measure for all λ < 2.538. Here we explore the other direction and prove that there are multiple Gibbs measures for all λ > 5.3506. We also show that with the methods we are using we cannot hope to replace 5.3506 with anything below 4.8771.
Our proof begins along the lines of the standard Peierls argument, but we add two innovations. First, following ideas of Kotecký and Randall, we construct an event that distinguishes two boundary conditions and always has long contours associated with it, obviating the need to accurately enumerate short contours. Second, we obtain improved bounds on the number of contours by relating them to a new class of self-avoiding walks on an oriented version of ℤ2.
To evaluate the impact of discontinuing routine contact precautions (CP) for endemic methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant Enterococcus (VRE) on hospital adverse events.
Academic medical center with single-occupancy rooms.
We compared hospital reportable adverse events 1 year before and 1 year after discontinuation of routine CP for endemic MRSA and VRE (preintervention and postintervention periods, respectively). Throughout the preintervention period, daily chlorhexidine gluconate bathing was expanded to nearly all inpatients. Chart reviews were performed to identify which patients and events were associated with CP for MRSA/VRE in the preintervention period as well as the patients that would have met prior criteria for MRSA/VRE CP but were not isolated in the postintervention period. Adverse events during the 2 periods were compared using segmented and mixed-effects Poisson regression models.
There were 24,732 admissions in the preintervention period and 25,536 in the postintervention period. Noninfectious adverse events (ie, postoperative respiratory failure, hemorrhage/hematoma, thrombosis, wound dehiscence, pressure ulcers, and falls or trauma) decreased by 19% (12.3 to 10.0 per 1,000 admissions, P=.022) from the preintervention to the postintervention period. There was no significant difference in the rate of infectious adverse events after CP discontinuation (20.7 to 19.4 per 1,000 admissions, P=.33). Patients with MRSA/VRE showed the largest reduction in noninfectious adverse events after CP discontinuation, with a 72% reduction (21.4 to 6.08 per 1,000 MRSA/VRE admissions; P<.001).
After discontinuing routine CP for endemic MRSA/VRE, the rate of noninfectious adverse events declined, especially in patients who no longer required isolation. This suggests that elimination of CP may substantially reduce noninfectious adverse events.
In a cohort of inpatients with hematologic malignancy and positive enzyme immunoassay (EIA) or polymerase chain reaction (PCR) Clostridium difficile tests, we found that clinical characteristics and outcomes were similar between these groups. The method of testing is unlikely to predict infection in this population, and PCR-positive results should be treated with concern.
We undertook observations with the Green Bank Telescope, simultaneously with the 300 m telescope in Arecibo, as a follow-up of a possible flare of radio emission from Ross 128. We report here the non-detections from the GBT observations in C band (4–8 GHz), as well as non-detections in archival data at L band (1.1–1.9 GHz). We suggest that a likely scenario is that the emission comes from one or more satellites passing through the same region of the sky.
Landscape geophysical survey around the small upland ‘henge’ at Yarnbury, Grassington, North Yorkshire revealed few anthropogenic features around the enclosure but did identify a small rectangular structure in the same field. Sample trenching of this feature, radiocarbon and archaeomagnetic dating proved it to be an earlier Neolithic post and wattle structure of a type that is being increasingly recognised in Ireland and the west of Britain. It is the first to be recognised in the Yorkshire Dales and it is argued that the Dales may have been pivotal in the Neolithic for east–west trade as well as pastoral upland agriculture.
To evaluate the impact of discontinuation of contact precautions (CP) for methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant Enterococcus (VRE) and expansion of chlorhexidine gluconate (CHG) use on the health system.
We compared hospital-wide laboratory-identified clinical culture rates (as a marker of healthcare-associated infections) 1 year before and after routine CP for endemic MRSA and VRE were discontinued and CHG bathing was expanded to all units. Culture data from patients and cost data on material utilization were collected. Nursing time spent donning personal protective equipment was assessed and quantified using time-driven activity-based costing.
Average positive culture rates before and after discontinuing CP were 0.40 and 0.32 cultures/100 admissions for MRSA (P=.09), and 0.48 and 0.40 cultures/100 admissions for VRE (P=.14). When combining isolation gown and CHG costs, the health system saved $643,776 in 1 year. Before the change, 28.5% intensive care unit and 19% medicine/surgery beds were on CP for MRSA/VRE. On the basis of average room entries and donning time, estimated nursing time spent donning personal protective equipment for MRSA/VRE before the change was 45,277 hours/year (estimated cost, $4.6 million).
Discontinuing routine CP for endemic MRSA and VRE did not result in increased rates of MRSA or VRE after 1 year. With cost savings on materials, decreased healthcare worker time, and no concomitant increase in possible infections, elimination of routine CP may add substantial value to inpatient care delivery.
Polar deciduous forests were an important biome during much of the Mesozoic and Paleogene, occupying upwards of 40% of the total land surface. Little is known about their physiological ecology, however, because these types of forests do not exist for study today. Furthermore, the role of high atmospheric CO2 levels in modulating the physiological response of ancient polar forests is poorly known. Here we report detailed measurements of whole-tree net carbon uptake over a full annual cycle for five tree species whose close ancestors were components of Cretaceous and Paleogene polar forests. Measurements were made on both evergreen and deciduous species after two years growth in a simulated Mesozoic polar (69°N) environment at either ambient (400 ppmv) or elevated (800 ppmv) levels of CO2. The deciduous species exhibited a significant pulse in carbon uptake during the late summer and early autumn (August to mid-October) that enabled them to achieve annual carbon budgets similar to those of evergreen trees, despite incurring higher carbon losses through annual leaf shedding. Area-based photosynthetic rates dropped progressively in all species during the polar summer (June to mid-July), resulting in decreases in whole-tree carbon uptake late in the polar summer. The high-CO2-grown trees were more strongly affected by this polar summer depression than the low-CO2-grown trees. Our results indicate that, from a carbon balance perspective, deciduous taxa have no clear advantage over evergreens. Moreover, the seasonal patterns reported here suggest that at latitudes poleward of 69°, evergreens will be even more strongly favored. The consideration of factors not directly related to carbon budgeting is probably therefore required to fully understand the adaptive significance of the deciduous leaf habit in ancient polar forests.
Psychomotor slowing has been documented in depression. The digital Clock Drawing Test (dCDT) provides: (i) a novel technique to assess both cognitive and motor aspects of psychomotor speed within the same task and (ii) the potential to uncover subtleties of behavior not previously detected with non-digitized modes of data collection. Using digitized pen technology in 106 participants grouped by Age (younger/older) and Affect (euthymic/unmedicated depressed), we recorded cognitive and motor output by capturing how the clock is drawn rather than focusing on the final product. We divided time to completion (TTC) for Command and Copy conditions of the dCDT into metrics of percent of drawing (%Ink) versus non-drawing (%Think) time. We also obtained composite Z-scores of cognition, including attention/information processing (AIP), to explore associations of %Ink and %Think times to cognitive and motor performance. Despite equivalent TTC, %Ink and %Think Command times (Copy n.s.) were significant (AgeXAffect interaction: p=.03)—younger depressed spent a smaller proportion of time drawing relative to thinking compared to the older depressed group. Command %Think time negatively correlated with AIP in the older depressed group (r=−.46; p=.02). Copy %Think time negatively correlated with AIP in the younger depressed (r=−.47; p=.03) and older euthymic groups (r=−.51; p=.01). The dCDT differentiated aspects of psychomotor slowing in depression regardless of age, while dCDT/cognitive associates for younger adults with depression mimicked patterns of older euthymics. (JINS, 2014, 20, 1–9)
Lurasidone is an atypical antipsychotic medication approved for the treatment of schizophrenia over a dose range of 40–160 mg/day. This study examined D2 receptor occupancy and its association with clinical improvement and side effects in patients with schizophrenia or schizoaffective disorder following repeated doses of 80, 120, or 160 mg/day of lurasidone.
Twenty-five patients with The Diagnostic and Statistical Manual of Mental Disorders, 4th ed. (DSM-IV) diagnoses of schizophrenia or schizoaffective disorder were washed out of their antipsychotic medications (5 half-lives) and randomly assigned to 80, 120, or 160 mg/day of lurasidone. Subjects were imaged with 18F-fallypride at baseline and at steady-state lurasidone treatment to determine D2 receptor occupancy.
Blood lurasidone concentration (plus major metabolite), but not dose, significantly correlated with D2 receptor occupancy. D2 receptor occupancy in several subcortical structures is associated with positive but not negative symptom improvement or the presence of movement symptoms.
Blood concentrations greater than 70 ng/mL may be required to achieve a 65% occupancy level in subcortical areas. Intersubject blood concentrations at fixed dose were highly variable and may account for the lack of dose correlations.
Positron emission tomography (PET) occupancy data suggest that greater than 65% occupancy can be achieved across the dose range of 80–160 mg/day and that some patients require higher doses to achieve antipsychotic efficacy; this finding supports prior randomized clinical trial results.
Central line-associated bloodstream infection (CLABSI) is a national target for mandatory reporting and a Centers for Medicare and Medicaid Services target for value-based purchasing. Differences in chart review versus claims-based metrics used by national agencies and groups raise concerns about the validity of these measures.
Evaluate consistency and reasons for discordance among chart review and claims-based CLABSI events.
We conducted 2 multicenter retrospective cohort studies within 6 academic institutions. A total of 150 consecutive patients were identified with CLABSI on the basis of National Healthcare Safety Network (NHSN) criteria (NHSN cohort), and an additional 150 consecutive patients were identified with CLABSI on the basis of claims codes (claims cohort). Ail events had full-text medical record reviews and were identified as concordant or discordant with the other metric.
In the NHSN cohort, there were 152 CLABSIs among 150 patients, and 73.0% of these cases were discordant with claims data. Common reasons for the lack of associated claims codes included coding omission and lack of physician documentation of bacteremia cause. In the claims cohort, there were 150 CLABSIs among 150 patients, and 65.3% of these cases were discordant with NHSN criteria. Common reasons for the lack of NHSN reporting were identification of non-CLABSI with bacteremia meeting Centers for Disease Control and Prevention (CDC) criteria for an alternative infection source.
Substantial discordance between NHSN and claims-based CLABSI indicators persists. Compared with standardized CDC chart review criteria, claims data often had both coding omissions and misclassification of non-CLABSI infections as CLABSI. Additionally, claims did not identify any additional CLABSIs for CDC reporting. NHSN criteria are a more consistent interhospital standard for CLABSI reporting.
Recent Hα surveys such as SHS and IPHAS have improved the completeness of the Galactic planetary nebula (PN) census. We now know of ∼3000 PNe in the Galaxy, but this is far short of most estimates, typically ~25 000 or more for the total population. The size of the Galactic PN population is required to derive an accurate estimate of the chemical enrichment rates of nitrogen, carbon, and helium. In addition, a high PN count (>20 000) is strong evidence that most main-sequence stars of mass 1–8 M⊙ will go through a PN phase, while a low count (<10 000) argues that special conditions (e.g. close binary interactions) are required to form a PN. We describe a technique for finding hundreds more PNe using the existing data collections of the digital sky surveys, thereby improving the census of Galactic PNe.
Hydrodynamic effects of the relationship between the roll and pitch oscillations in low-aspect-ratio fins, with a laminar section and a rounded leading edge, flapping at transitional to moderately high Reynolds numbers, are considered. The fin is hinged at one end and its roll amplitude is large. Also examined is how this relationship is affected by spanwise twist, which alters the pitch oscillation amplitude and its phase relative to the roll motion. Force, efficiency and surface hot-film-anemometry measurements, and flow visualization are carried out in a tow tank. A fin of an abstracted penguin-wing planform and a NACA 0012 cross-section is used, and the chord Reynolds number varies from 3558 to 150 000 based on total speed. The fin is forced near the natural shedding frequency. Strouhal number and pitch amplitude are directly related when thrust is produced, and efficiency is maximized in narrow combinations of Strouhal number and pitch amplitude when oscillation of the leading-edge stagnation point is minimal. Twist makes the angle of attack uniform along the span and enhances thrust by up to 24 %, while maintaining high efficiency. Only 5 % of the power required to roll is spent to pitch, and yet roll and pitch are directly related. During hovering, dye visualization shows that a diffused leading-edge vortex is produced in rigid fins, which enlarges along the span; however, twist makes the vortex more uniform and the fin in turn requires less power to roll. Low-order phase maps of the measurements of force oscillation versus its derivative are modelled as due to van der Pol oscillators; the higher-order maps show trends in the sub-regimes of the transitional Reynolds number. Fin oscillation imparts a chordwise fluid motion, yielding a Stokes wave in the near-wall vorticity layer. When the roll and pitch oscillations are directly related, the wave is optimized: causing vorticity lift-up as the fin is decelerated at the roll extremity; the potential energy at the stagnation point is converted into kinetic energy; a vortex is produced as the lifted vorticity is wrapped around the leading edge; and free-stream reattachment keeps the vortex trapped. When the twist oscillation is phased along the span, this vortex becomes self-preserving at all amplitudes of twist, indicating the most stable (low-bandwidth) tuned nature.
Nanotechnology has moved quickly from the realm of theoretical science and science fiction to the stuff of everyday life for people across the world. Nanotechnology is deployed in hundreds of products and services and will soon be part of many thousands of products and services. Estimates vary, but nanotechnology is a multi-billion dollar enterprise worldwide now and could become a trillion dollar enterprise in the relatively near term. Everything from socks to tennis rackets to food to surgical techniques to state-of-the-art military technology now may include some form of nanotechnology. If petroleum and plastics formed the infrastructure of the chemical/industrial revolution that transformed countries such as the United States in the last 50 to 100 years, nanotechnology and nanotechnology products may well be the tiny – the nano – basis for the next gigantic revolution in how we live.
As Kimberly Gray explains in her contribution to this volume, nanoparticles – extremely tiny particles – have always existed and have been known to exist for a very long time. The nanotechnology revolution began when technologies were developed that allowed nanoparticles to be accurately imaged and manipulated to produce materials having surprising properties of value in a wide range of applications. Nanotechnology is not per se the realm of the very, very small, but of the engineered and manipulated very, very small. Indeed, the promise of nanotechnology is that atoms and molecules of common elements such as silver and carbon can be manipulated into so many shapes and with so many different surface modifications that they can perform a vast array of new functions.