246 research outputs found
Hospital case volume and outcomes for proximal femoral fractures in the USA: an observational study
Objective: To explore whether older adults with isolated hip fractures benefit from treatment in high-volume hospitals.
Design: Population-based observational study.
Setting: All acute hospitals in California, USA.
Participants: All individuals aged >65 that underwent an operation for an isolated hip fracture in California between 2007 and 2011. Patients transferred between hospitals were excluded.
Primary and secondary outcomes: Quality indicators (time to surgery) and patient outcomes (length of stay, in-hospital mortality, unplanned 30-day re-admission, and selected complications).
Results: 91,401 individuals satisfied the inclusion criteria. Time to operation and length of stay were significantly prolonged in low volume hospitals, by 1.96 (95% CI 1.20-2.73) and 0.70 (0.38-1.03) days respectively. However, there were no differences in clinical outcomes, including in-hospital mortality, 30-day re-admission, and rates of pneumonia, pressure ulcers, and venous thromboembolism.
Conclusion: These data suggest that there is no patient safety imperative to limit hip fracture care to high-volume hospitals
Band-Gap Nonlinearity in Lead Chalcogenide (PbQ, Q = Te, Se, S) Alloys
Narrow band-gap lead chalcogenides have been developed
for several optical and electronic applications. However, band-gap energies
of the ternary and quaternary alloys have received little attention compared
with the parent binary phases. Here, we have fabricated single-phase
ternary (PbTe)1−x(PbSe)x and quaternary (PbTe)0.9−y(PbSe)0.1(PbS)y and
(PbTe)0.65−z(PbSe)0.35(PbS)z alloys and shown that although lattice
parameters follow Vegard’s law as a function of composition, the bandgap
energies exhibit a substantial bowing effect. The ternary
(PbTe)1−x(PbSe)x system features a smaller bowing parameter predominantly
due to the difference in electronegativity between Se and Te,
whereas the larger bowing parameters in quaternary alloys are generated
from a larger crystal lattice mismatch and larger miscibility gap. These
findings can lead to further advances in tuning the band-gap and lattice
parameters for optical and electronic applications of lead chalcogenides
A review of the use of terrestrial laser scanning application for change detection and deformation monitoring of structures
Change detection and deformation monitoring is an active area of research within the field of engineering surveying as well as overlapping areas such as structural and civil engineering. The application of Terrestrial Laser Scanning (TLS) techniques for change detection and deformation monitoring of concrete structures has increased over the years as illustrated in the past studies. This paper presents a review of literature on TLS application in the monitoring of structures and discusses registration and georeferencing of TLS point cloud data as a critical issue in the process chain of accurate deformation analysis. Past TLS research work has shown some trends in addressing issues such as accurate registration and georeferencing of the scans and the need of a stable reference frame, TLS error modelling and reduction, point cloud processing techniques for deformation analysis, scanner calibration issues and assessing the potential of TLS in detecting sub-centimetre and millimetre deformations. However, several issues are still open to investigation as far as TLS is concerned in change detection and deformation monitoring studies such as rigorous and efficient workflow methodology of point cloud processing for change detection and deformation analysis, incorporation of measurement geometry in deformation measurements of high-rise structures, design of data acquisition and quality assessment for precise measurements and modelling the environmental effects on the performance of laser scanning. Even though some studies have attempted to address these issues, some gaps exist as information is still limited. Some methods reviewed in the case studies have been applied in landslide monitoring and they seem promising to be applied in engineering surveying to monitor structures. Hence the proposal of a three-stage process model for deformation analysis is presented. Furthermore, with technological advancements new TLS instruments with better accuracy are being developed necessitating more research for precise measurements in the monitoring of structures
Gene-centric association analysis for the correlation between the guanine-cytosine content levels and temperature range conditions of prokaryotic species
Experimental study of negative photoconductivity in n-PbTe(Ga) epitaxial films
We report on low-temperature photoconductivity (PC) in n-PbTe(Ga) epitaxial
films prepared by the hot-wall technique on -BaF_2 substrates. Variation
of the substrate temperature allowed us to change the resistivity of the films
from 10^8 down to 10_{-2} Ohm x cm at 4.2 K. The resistivity reduction is
associated with a slight excess of Ga concentration, disturbing the Fermi level
pinning within the energy gap of n-PbTe(Ga). PC has been measured under
continuous and pulse illumination in the temperature range 4.2-300 K. For films
of low resistivity, the photoresponse is composed of negative and positive
parts. Recombination processes for both effects are characterized by
nonexponential kinetics depending on the illumination pulse duration and
intensity. Analysis of the PC transient proves that the negative
photoconductivity cannot be explained in terms of nonequilibrium charge
carriers spatial separation of due to band modulation. Experimental results are
interpreted assuming the mixed valence of Ga in lead telluride and the
formation of centers with a negative correlation energy. Specifics of the PC
process is determined by the energy levels attributed to donor Ga III, acceptor
Ga I, and neutral Ga II states with respect to the crystal surrounding. The
energy level corresponding to the metastable state Ga II is supposed to occur
above the conduction band bottom, providing fast recombination rates for the
negative PC. The superposition of negative and positive PC is considered to be
dependent on the ratio of the densities of states corresponding to the donor
and acceptor impurity centers.Comment: 7 pages, 4 figure
Recommended from our members
Memory for medication side effects in younger and older adults: the role of subjective and objective importance
Older adults often experience memory impairments, but can sometimes use selective processing and schematic support to remember important information. The current experiments investigate to what degree younger and healthy older adults remember medication side effects that were subjectively or objectively important to remember. Participants studied a list of common side effects, and rated how negative these effects were if they were to experience them, and were then given a free recall test. In Experiment 1, the severity of the side effects ranged from mild (e.g., itching) to severe (e.g., stroke), and in Experiment 2, certain side effects were indicated as critical to remember (i.e., “contact your doctor if you experience this”). There were no age differences in terms of free recall of the side effects, and older adults remembered more severe side effects relative to mild effects. However, older adults were less likely to recognize critical side effects on a later recognition test, relative to younger adults. The findings suggest that older adults can selectively remember medication side effects, but have difficulty identifying familiar but potentially critical side effects, and this has implications for monitoring medication use in older age
Effects of soil moisture and plant interactions on the soil microbial community structure
- …