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A K-band (18-25 GHz) reflected-wave ruby maser (Moore and Clauss 1979) has been borrowed from the National Radio Astronomy Observatory for radio astronomy use on the NASA 64-m antenna of the Deep Space Network at the Tidbinbilla Tracking Station, near Canberra. The purpose of the installation is to provide additional sensitive spectral line, continuum, and VLBI capabilities in the southern hemisphere. Previous measurements at 22.3 GHz (λ = 13.5 mm) determined that the Tidbinbilla 64-m antenna has a peak aperture efficiency of ˜22%, a well-behaved beam shape and consistent pointing (Fourikis and Jauncey 1979). Before installing the maser on the antenna a cooled (circulator) switch was added to provide a beam-switching capability, and a spectral line receiver following the maser was incorporated. The system was assembled and tested at JPL in late 1980 and installed at Tidbinbilla early in 1981. We give here a brief description and present some of the first line observations made in February and March 1981. Extensive line and continuum observations are planned with the present system and a program is under way to determine the telescope pointing characteristics.
The Centers for Medicare and Medicaid Services (CMS) implemented a policy in October 2008 to eliminate additional Medicare payment for mediastinitis following coronary artery bypass graft (CABG) surgery.
To evaluate the impact of this policy on mediastinitis rates, using Medicare claims and National Healthcare Safety Network (NHSN) prospective surveillance data.
We used an interrupted time series design to compare mediastinitis rates before and after the policy, adjusted for secular trends. Billing rates came from Medicare inpatient claims following 638,761 CABG procedures in 1,234 US hospitals (January 2006-September 2010). Prospective surveillance rates came from 151 NHSN hospitals in 29 states performing 94,739 CABG procedures (January 2007-September 2010). Logistic regression mixed-effects models estimated trends for mediastinitis rates.
We found a sudden drop in coding for index admission mediastinitis at the time of policy implementation (odds ratio, 0.36 [95% confidence interval (CI), 0.23-0.57]) and a decreasing trend in coding for index admission mediastinitis in the postintervention period compared with the preintervention period (ratio of slopes, 0.83 [95% CI, 0.74-0.95]). However, we saw no impact of the policy on infection rates as measured using NHSN data. Our results were not affected by changes in patient risk over time, heterogeneity in hospital demographics, or timing of hospital participation in NHSN.
The CMS policy of withholding additional Medicare payment for mediastinitis on the basis of claims-based evidence of infection was associated with changes in coding for infections but not with changes in actual infection rates during the first 2 years after policy implementation.
The aim of this study was to investigate neurochemical and enzymatic changes in rats infected with Trypanosoma evansi, and their interference in the cognitive parameters. Behavioural assessment (assessment of cognitive performance), evaluation of cerebral L-[3H]glutamate uptake, acetylcholinesterase (AChE) activity and Ca+2 and Na+, K+-ATPase activity were evaluated at 5 and 30 days post infection (dpi). This study demonstrates a cognitive impairment in rats infected with T. evansi. At 5 dpi memory deficit was demonstrated by an inhibitory avoidance test. With the chronicity of the disease (30 dpi) animals showed anxiety symptoms. It is possible the inhibition of cerebral Na+, K+-ATPase activity, AChE and synaptosomal glutamate uptake are involved in cognitive impairment in infected rats by T. evansi. The understanding of cerebral host–parasite relationship may shed some light on the cryptic symptoms of animals and possibly human infection where patients often present with other central nervous system (CNS) disorders.
The purpose of this study was to develop a standardized tool for the assessment of surveillance systems on zoonoses and animal diseases. We reviewed three existing methods and combined them to develop a semi-quantitative assessment tool associating their strengths and providing a standardized way to display multilevel results. We developed a set of 78 assessment criteria divided into ten sections, representing the functional parts of a surveillance system. Each criterion was given a score according to the prescription of a scoring guide. Three graphical assessment outputs were generated using a specific combination of the scores. Output 1 is a general overview through a series of pie charts synthesizing the scores of each section. Output 2 is a histogram representing the quality of eight critical control points. Output 3 is a radar chart representing the level reached by ten system attributes. This tool was applied on five surveillance networks.
In-situ transmission electron microscopy (TEM) has developed rapidly over the last decade. In particular, with the inclusion of scanning probes in TEM holders, allows both mechanical and electrical testing to be performed whilst simultaneously imaging the microstructure at high resolution. In-situ TEM nanoindentation and tensile experiments require only an axial displacement perpendicular to the test surface. However, here, through the development of a novel in-situ TEM triboprobe, other surface characterisation experiments are now possible, with the introduction of a fully programmable 3D positioning system.
Programmable lateral displacement control allows scratch tests to be performed at high resolution with simultaneous imaging of the changing microstructure. With the addition of repeated cyclic movements, both nanoscale fatigue and friction experiments can also now be performed. We demonstrate a range of movement profiles for a variety of applications, in particular, lateral sliding wear.
The developed NanoLAB TEM triboprobe also includes a new closed loop vision control system for intuitive control during positioning and alignment. It includes an automated online calibration to ensure that the fine piezotube is controlled accurately throughout any type of test. Both the 3D programmability and the closed loop vision feedback system are demonstrated here.
An experimental investigation was conducted to determine the flow characteristics of shallow swept cavities at a free-stream Mach number of 2. The investigation described herein focused on obtaining information on both time-averaged and time-dependent flow features. The data consisted of steady and unsteady pressure measurements as well as some surface oil and schlieren flow visualisation. The effective length-to-depth ratios l/d of cavities investigated ranged between 5·65 and 8 for shallow ‘open’ cavities and between 11·31 and 16 for ‘closed’ cavities. The cavity sweep angles were 0°, 15° and 45°. The results of the swept cavities, when compared to the datum cases of the straight (0°) cavities, showed some distinct differences. With regard to time-averaged flow characteristics, in an open swept cavity (5·65 < l/d < 8), the flow displayed quasi-open flow behaviour, distorted by the spanwise cross flow within the cavity. In the case of the closed swept cavity (11·31 < l/d < 16), flow features resembling the ‘closed’ to ‘transitional closed’ cavity flow types were seen to exist simultaneously across the span. Unsteady pressure data indicated that for an open cavity at 15° sweep angle, the discrete frequencies observed were similar to those of a straight open cavity. In contrast to this, at 45° sweep angle, the frequencies were broadband with no discrete frequency across the cavity length. For the closed cavity, the frequencies were all broadband irrespective of the sweep angle. The investigation also showed that the influence of the sweep angle on the pressure drag of the cavity strongly depends on the type of cavity flow: a sweep angle increase from 0° to 45° approximately doubled the pressure drag for an open cavity, while it led to a drag reduction of about 37% for the closed cavity.
Seismology is the only way to investigate the internal structure of
the giant planets, with a lot of scientific implications such as
high pressure physics and huge constraints on the scenario of solar
system formation. As compared to other existing possibilities
(ground based network, spacecraft), seismology of Jupiter will take
a maximum benefit from the peculiarities of the Concordia station as
an astronomical observatory. Indeed, the continuous temporal
coverage for all the winter season, and the quality of the
atmospheric seeing, are crucial parameters for this program. The
jovian seismometer SYMPA, already used for network observations, is
perfectly suitable for Dome C conditions. With the already
existing small telescopes deployed in the frame of site testing
program, seismology of Jupiter will constitute a excellent
intermediate project with high scientific return, before the
installation of large telescopes. In a second step, such an
instrument could be a first light instrument for a 1.5 m class
automatic telescope, which is to be developed as an individual stone
for a large interferometer. With this diameter, the same scientific
program on Saturn could also be achieved.
In continuous hot dip galvanizing, in particular with galvannealing baths,
competitive reactions occur between iron, zinc and aluminium that may be affected
by other elements such as chromium. Based on thermodynamics modelling and experimental
descriptions, the zinc rich corner of the quaternary Fe-Zn-Al-Cr system is investigated
at 460°C. The results obtained contribute to a better knowledge of the reactivity
of steels in industrial galvanizing or galvannealing baths.
Estimates of the number of hospitalizations attributable to specific pathogens are required to predict the potential impact of vaccination. All hospital admissions for lower respiratory tract infection (LRI) in children <5 years in England in 1995–8 were reviewed. Most admissions (76.8%) were not associated with specific organisms. Seasonality in pathogens that cause bronchiolitis and pneumonia was used to predict the proportion of cases with unspecified aetiology attributable to different organisms using multiple linear regression. Of 12298 admissions for LRI, 17.5% were due to RSV infection. An estimated 74.8% (95% CI, 72.0–77.7%) of ‘unspecified bronchiolitis’ admissions and 16.3% (95% CI, 13.7–18.8%) of ‘unspecified pneumonia’ admissions were RSV related. The total mean annual incidence of hospital admissions attributable to RSV is 28.3/1000 children <1 year of age, and 1.3/1000 children 1–4 years old. The greater burden of RSV infection than indicated through discharge data is revealed through applying simple statistical methods.
The prevalence of active infection with Helicobacter pylori in the general population of England and Wales was estimated using high reactivity for specific IgG in serum ELISA as a marker. A total of 10118 anonymized residues of serum samples collected in 1986 and 1996 from persons aged 1–84 years were used. Estimated prevalence of active infection varied by region and was highest in London. Prevalence was related to decade of birth and increased from 4·3% in those born during the 1980s to 30% in those born before 1940. An estimated total of 7·5 million people living in England and Wales have an active infection and analysis by decade of birth showed no significant difference between samples collected in 1986 and 1996. These data suggest H. pylori infection is becoming less common, is acquired at an early age and is unlikely to be resolved unless suitable antimicrobial treatment is sought.
Nanowires of bismuth with diameters ranging from 10 to 200
nm and lengths of 50 μm have been synthesized by a pressure
injection method. Nanostructural and chemical compositional
studies using environmental and high resolution transmission
electron microscopy with electron stimulated energy dispersive
X-ray spectroscopy have revealed essentially single crystal
nanowires. The high resolution studies have shown that the
nanowires contain amorphous Bi-oxide layers of a few nanometers
on the surface. In situ environmental high resolution transmission
electron microscopy (environmental-HRTEM) studies at the atomic
level, in controlled hydrogen and other reducing gas environments
at high temperatures demonstrate that gas reduction can be
successfully applied to remove the oxide nanolayers and to maintain
the dimensional and structural uniformity of the nanowires,
which is key to attaining low electrical contact resistance.
Many countries are currently studying the possibility of mass vaccination against varicella. The objective of this study was to provide a comprehensive picture of the pre-vaccine epidemiology of the varicella zoster virus (VZV) to aid in the design of immunization programs and to adequately measure the impact of vaccination. Population-based data including physician visit claims, sentinel surveillance and hospitalization data from Canada and the United Kingdom were analysed. The key epidemiological characteristics of varicella and zoster (age specific consultation rates, seasonality, force of infection, hospitalization rates and inpatient days) were compared. Results show that the overall epidemiology of varicella and zoster is remarkably similar between the two countries. The major difference being that, contrary to Canada, the epidemiology of varicella seems to be changing in the United Kingdom with an important decrease in the average age at infection that coincides with a significant increase in children attending preschool. Furthermore, differences exist in the seasonality between the United Kingdom and Canada, which seem to be primarily due to the school calendar. These results illustrate that school and preschool contact patterns play an important role in the dynamics of varicella. Finally, our results provide baseline estimates of varicella and zoster incidence and morbidity for VZV vaccine effectiveness and cost-effectiveness studies.
To estimate the extent of, and evaluate risk factors for, elevated carboxyhemoglobin levels among patients undergoing general anesthesia and to identify the source of carbon monoxide.
Matched case-control study to measure carboxyhemoglobin levels.
Large academic medical center.
45 surgical patients who underwent general anesthesia.
Case-patients were more likely than controls to undergo surgery on Monday or Tuesday (10/15 vs 7/30; matched odds ratio [mOR], 7.7; 95% confidence interval [CI95], 1.8-34; P=.01), in one particular room (7/15 vs 4/30; mOR, 8.5; CI95, 1.5-48; P=.03) or in a room that was idle for ≥24 hours (11/15 vs 1/30; mOR, 95.5; CI95, 8.0-1,138; P≤.001). In a multivariate model, only rooms, and hence the anesthesia equipment, that were idle for ≥24 hours were independently associated with elevated intraoperative carboxyhemoglobin levels (OR, 22.4; CI95, 1.5-338; P=.025). Moreover, peak carboxyhemoglobin levels were correlated with the length of time that the room was idle (r=0.7; CI95, 0.3-0.9). Carbon monoxide was detected in the anesthesia machine outflow during one case-procedure. No contamination of anesthesia gas supplies or CO2 absorbents was found.
Carbon monoxide may accumulate in anesthesia circuits left idle for ≥24 hours as a result of a chemical interaction between CO2-absorbent granules and anesthetic gases. Patients administered anesthesia through such circuits may be at increased risk for elevated carboxyhemoglobin levels during surgery or the early postoperative period.
The objective of this study was to develop and apply a dynamic mathematical model of VZV
transmission to predict the effect of different vaccination strategies on the age-specific incidence
and outcome of infection. To do so a deterministic realistic age-structured model (RAS) was
used which takes account of the increased potential for transmission within school aged
groups. Various vaccine efficacy scenarios, vaccine coverages and vaccination strategies were
investigated and a sensitivity analysis of varicella incidence predictions to important parameters
was performed. The model predicts that the overall (natural and breakthrough) incidence and
morbidity of varicella would likely be reduced by mass vaccination of 12-month-old children.
Furthermore, adding a catch-up campaign in the first year for 1–11 year olds seems to be the
most effective strategy to reduce both varicella incidence and morbidity (in the short and
long term), though with the possible detrimental effect of increasing the incidence of zoster.
We have synthesized single crystal bismuth nanowires by pressure injecting molten Bi into anodic alumina templates. By varying the template fabrication conditions, nanowires with diameters ranging from 10 to 200nm and lengths of ~50[.proportional]m can be produced. We present a scheme for measuring the resistance of a single Bi nanowire using a 4-point measurement technique. The nanowires are found to have a 7nm thick oxide layer which causes very high contact resistance when electrodes are patterned on top of the nanowires. The oxide is found to be resilient to acid etching, but can be successfully reduced in high temperature hydrogen and ammonia environments. The reformation time of the oxide in air is found to be less than 1 minute. Focused ion beam milling is attempted as an alternate solution to oxide removal.