134 research outputs found
HRâpQCT measures of bone microarchitecture predict fracture : systematic review and metaâanalysis
HRâpQCT is a nonâinvasive imaging modality for assessing volumetric bone mineral density (vBMD) and microarchitecture of cancellous and cortical bone. The objective was to (i) assess fractureâassociated differences in HRâpQCT bone parameters and (ii) to determine if HRâpQCT is sufficiently precise to reliably detect these differences in individuals. We systematically identified 40 studies that used HRâpQCT (39/40 used XtremeCT scanners) to assess 1291â3253 and 3389â10,687 individuals with and without fractures, respectively, ranging in age from 10.9 to 84.7âyears with no comorbid conditions. Parameters describing radial and tibial bone density, microarchitecture, and strength were extracted and percentage differences between fracture and control subjects were estimated using a random effects metaâanalysis. An additional metaâanalysis of shortâterm in vivo reproducibility of bone parameters assessed by XtremeCT was conducted to determine whether fractureâassociated differences exceeded the least significant change (LSC) required to discern measured differences from precision error. Radial and tibial HRâpQCT parameters, including failure load, were significantly altered in fracture subjects, with differences ranging from â2.6% (95% CI: â3.4 to â1.9) in radial cortical vBMD to â12.6% (95% CI: â15.0 to â10.3) in radial trabecular vBMD. Fractureâassociated differences reported by prospective studies were consistent with those from retrospective studies, indicating that HRâpQCT can predict incident fracture. Assessment of study quality, heterogeneity and publication biases verified the validity of these findings. Finally, we demonstrated that fractureâassociated deficits in total and trabecular vBMD, and certain tibial cortical parameters, can be reliably discerned from HRâpQCTârelated precision error and can be used to detect fractureâassociated differences in individual patients. Although differences in other HRâpQCT measures, including failure load, were significantly associated with fracture, improved reproducibility is needed to ensure reliable individual crossâsectional screening and longitudinal monitoring. In conclusion, our study supports the use of HRâpQCT in clinical fracture prediction
HEPA respirators and tuberculosis in hospital workers
Adal et al. (July 21 issue)1 demonstrate that at the University of Virginia Hospital, where the incidence of tuberculosis is low, the infection controls already instituted may be sufficient and the cost of adding respirators with high-efficiency particulate air filters (HEPA respirators) for their 3852 workers is impressively high. The situation is different at our hospital, Lincoln Medical and Mental Health Center in South Bronx, New York. In contrast to their figure of 11 patients with documented tuberculosis per year, we have over 160 such patients per year, of whom approximately 30 percent have multidrug-resistant tuberculosis
Many body physics from a quantum information perspective
The quantum information approach to many body physics has been very
successful in giving new insight and novel numerical methods. In these lecture
notes we take a vertical view of the subject, starting from general concepts
and at each step delving into applications or consequences of a particular
topic. We first review some general quantum information concepts like
entanglement and entanglement measures, which leads us to entanglement area
laws. We then continue with one of the most famous examples of area-law abiding
states: matrix product states, and tensor product states in general. Of these,
we choose one example (classical superposition states) to introduce recent
developments on a novel quantum many body approach: quantum kinetic Ising
models. We conclude with a brief outlook of the field.Comment: Lectures from the Les Houches School on "Modern theories of
correlated electron systems". Improved version new references adde
Reflections on IDEAL: What we have learnt from a unique calf cohort study
The year 2020 marks a decade since the final visit was made in the âInfectious Diseases of East African Livestockâ
(IDEAL) project. However, data generation from samples obtained during this ambitious longitudinal study still
continues. As the project launches its extensive open-access database and biobank to the scientific community,
we reflect on the challenges overcome, the knowledge gained, and the advantages of such a project. We discuss
the legacy of the IDEAL project and how it continues to generate evidence since being adopted by the Centre for
Tropical Livestock Genetics and Health (CTLGH). We also examine the impact of the IDEAL project, from the
authors perspective, for each of the stakeholders (the animal, the farmer, the consumer, the policy maker, the
funding body, and the researcher and their institution) involved in the project and provide recommendations for
future researchers who are interested in running longitudinal field studies.The Bill & Melinda Gates Foundation, the UK Governmentâs Department for International Development and the International Livestock Research Institute.http://www.elsevier.com/locate/prevetmedam2021Veterinary Tropical Disease
Superstripes and complexity in high-temperature superconductors
While for many years the lattice, electronic and magnetic complexity of
high-temperature superconductors (HTS) has been considered responsible for
hindering the search of the mechanism of HTS now the complexity of HTS is
proposed to be essential for the quantum mechanism raising the superconducting
critical temperature. The complexity is shown by the lattice heterogeneous
architecture: a) heterostructures at atomic limit; b) electronic heterogeneity:
multiple components in the normal phase; c) superconducting heterogeneity:
multiple superconducting gaps in different points of the real space and of the
momentum space. The complex phase separation forms an unconventional granular
superconductor in a landscape of nanoscale superconducting striped droplets
which is called the "superstripes" scenario. The interplay and competition
between magnetic orbital charge and lattice fluctuations seems to be essential
for the quantum mechanism that suppresses thermal decoherence effects at an
optimum inhomogeneity.Comment: 20 pages, 3 figures; J. Supercon. Nov. Mag. 201
Biomass offsets little or none of permafrost carbon release from soils, streams, and wildfire: an expert assessment
As the permafrost region warms, its large organic carbon pool will be increasingly vulnerable to decomposition, combustion, and hydrologic export. Models predict that some portion of this release will be offset by increased production of Arctic and boreal biomass; however, the lack of robust estimates of net carbon balance increases the risk of further overshooting international emissions targets. Precise empirical or model-based assessments of the critical factors driving carbon balance are unlikely in the near future, so to address this gap, we present estimates from 98 permafrost-region experts of the response of biomass, wildfire, and hydrologic carbon flux to climate change. Results suggest that contrary to model projections, total permafrost-region biomass could decrease due to water stress and disturbance, factors that are not adequately incorporated in current models. Assessments indicate that end-of-the-century organic carbon release from Arctic rivers and collapsing coastlines could increase by 75% while carbon loss via burning could increase four-fold. Experts identified water balance, shifts in vegetation community, and permafrost degradation as the key sources of uncertainty in predicting future system response. In combination with previous findings, results suggest the permafrost region will become a carbon source to the atmosphere by 2100 regardless of warming scenario but that 65%â85% of permafrost carbon release can still be avoided if human emissions are actively reduced
Consensus on the use and interpretation of cystic fibrosis mutation analysis in clinical practice
It is often challenging for the clinician interested in cystic fibrosis (CF) to interpret molecular genetic results, and to integrate them in the diagnostic process. The limitations of genotyping technology, the choice of mutations to be tested, and the clinical context in which the test is administered can all influence how genetic information is interpreted. This paper describes the conclusions of a consensus conference to address the use and interpretation of CF mutation analysis in clinical settings
- âŠ