9,097 research outputs found
The resonance amplitude associated with the Gamow states
The Gamow states describe the quasinormal modes of quantum systems. It is
shown that the resonance amplitude associated with the Gamow states is given by
the complex delta function. It is also shown that under the near-resonance
approximation of neglecting the lower bound of the energy, such resonance
amplitude becomes the Breit-Wigner amplitude. This result establishes the
precise connection between the Gamow states, Nakanishi's complex delta function
and the Breit-Wigner amplitude. In addition, this result provides another
theoretical basis for the phenomenological fact that the almost-Lorentzian
peaks in cross sections are produced by intermediate, unstable particles
How much variation in oocyte yield after controlled ovarian stimulation can be explained? A multilevel modelling study
How much variation in oocyte yield after controlled ovarian stimulation (COS) can be accounted for by known patient and treatment characteristics
A Upf3b-mutant mouse model with behavioral and neurogenesis defects.
Nonsense-mediated RNA decay (NMD) is a highly conserved and selective RNA degradation pathway that acts on RNAs terminating their reading frames in specific contexts. NMD is regulated in a tissue-specific and developmentally controlled manner, raising the possibility that it influences developmental events. Indeed, loss or depletion of NMD factors have been shown to disrupt developmental events in organisms spanning the phylogenetic scale. In humans, mutations in the NMD factor gene, UPF3B, cause intellectual disability (ID) and are strongly associated with autism spectrum disorder (ASD), attention deficit hyperactivity disorder (ADHD) and schizophrenia (SCZ). Here, we report the generation and characterization of mice harboring a null Upf3b allele. These Upf3b-null mice exhibit deficits in fear-conditioned learning, but not spatial learning. Upf3b-null mice also have a profound defect in prepulse inhibition (PPI), a measure of sensorimotor gating commonly deficient in individuals with SCZ and other brain disorders. Consistent with both their PPI and learning defects, cortical pyramidal neurons from Upf3b-null mice display deficient dendritic spine maturation in vivo. In addition, neural stem cells from Upf3b-null mice have impaired ability to undergo differentiation and require prolonged culture to give rise to functional neurons with electrical activity. RNA sequencing (RNAseq) analysis of the frontal cortex identified UPF3B-regulated RNAs, including direct NMD target transcripts encoding proteins with known functions in neural differentiation, maturation and disease. We suggest Upf3b-null mice serve as a novel model system to decipher cellular and molecular defects underlying ID and neurodevelopmental disorders
Invertible Sobolev functions: counterexamples and applications to nonlinear elasticity
Tesis Doctoral inĂ©dita leĂda en la Universidad AutĂłnoma de Madrid, Facultad de Ciencias, Departamento de Matemáticas. Fecha de lectura: 23-06-201
ACE inhibitor and angiotensin receptor-II antagonist prescribing and hospital admissions with acute kidney injury: A longitudinal ecological study
This is the final version. Available from the publisher via the DOI in this record.Background: ACE Inhibitors (ACE-I) and Angiotensin-Receptor Antagonists (ARAs) are commonly prescribed but can cause acute kidney injury (AKI) during intercurrent illness. Rates of hospitalization with AKI are increasing. We aimed to determine whether hospital AKI admission rates are associated with increased ACE-I/ARA prescribing. Methods and Findings: English NHS prescribing data for ACE-I/ARA prescriptions were matched at the level of the general practice to numbers of hospital admissions with a primary diagnosis of AKI. Numbers of prescriptions were weighted for the demographic characteristics of general practices by expressing prescribing as rates where the denominator is Age, Sex, and Temporary Resident Originated Prescribing Units (ASTRO-PUs). We performed a mixed-effect Poisson regression to model the number of admissions for AKI occurring in each practice for each of 4 years from 1/4/2007. From 2007/8-2010/11, crude AKI admission rates increased from 0.38 to 0.57 per 1000 patients (51.6% increase), and national annual ACE-I/ARA prescribing rates increased by 0.032 from 0.202 to 0.234 (15.8% increase). There was strong evidence (p<0.001) that increases in practice-level prescribing of ACE-I/ARA over the study period were associated with an increase in AKI admission rates. The increase in prescribing seen in a typical practice corresponded to an increase in admissions of approximately 5.1% (rate ratio = 1.051 for a 0.03 per ASTRO-PU increase in annual prescribing rate, 95%CI 1.047-1.055). Using the regression model we predict that 1,636 (95%CI 1,540-1,780) AKI admissions would have been avoided if prescribing rates were at the 2007/8 level, equivalent to 14.8% of the total increase in AKI admissions. Conclusion: In this ecological analysis, up to 15% of the increase in AKI admissions in England over a 4-year time period is potentially attributable to increased prescribing of ACE-I and ARAs. However, these findings are limited by the lack of patient level data such as indication for prescribing and patient characteristics. © 2013 Tomlinson et al.Cambridge Biomedical Research InstituteBritish Heart Foundatio
Nonequilibrium Josephson-like effects in wide mesoscopic S-N-S junctions
Mesoscopic superconducting-normal-metal-superconducting (S-N-S) junctions
with a large separation between the superconducting electrodes (i.e. wide
junctions) exhibit nonequilibrium supercurrents, even at temperatures for which
the equilibrium Josephson effect is exponentially small. The second harmonic of
the Josephson frequency dominates these currents, as observed in recent
experiments. A simple description of these effects, in the spirit of the
Resistively-Shunted-Junction model, is suggested here. It is used to calculate
dc I-V characteristics, and to examine the effects of various types of noise
and of external microwave radiation (Shapiro steps). It is found that the
nonequilibrium supercurrents are excited when the junction is driven by a dc
bias or an ac bias, or even by external noise. In the case of junctions which
are also long in the direction perpendicular to the current flow, thermodynamic
phase fluctuations (thermal noise) alone can drive the quasiparticles out of
local equilibrium. Magnetic flux is then predicted to be trapped in units of
Phi_0 /2 = hc/4e.Comment: 10 pages, to appear in a special issue of Superlattices &
Microstructure
Craniometric variation among Brazilian and Scottish populations: a physical anthropology approach
The present investigation intended to compare the craniometric variations of two samples of different nationalities (Brazilian and Scottish). Materials and methods: The Brazilian sample consisted of 100 modern complete skulls, including 53 female skulls and 47 male skulls, and the Scottish sample consisted of 100 historical skulls (61 males, 39 females) and 36 mandibles (24 males, 12 females). The cranial measurement protocol was composed of 40 measurements, 11 bilateral and 29 unilateral, and the measurement protocol of the mandible was composed of 15 measurements, with six that were bilateral and nine that were unique. The comparative analysis of the metric variability between the two samples was performed using the means and medians analysis, the t-test, the Wilcoxon test, and the coefficient of variance, with a significance level of 5%. Results: The results showed that, among the 72 analysed variables, 44 measurements (61.11%) presented statistical differences between the samples. The Scottish skull tends to have a cranial length (GOL diff=5.53), breadth (XCB diff=3.78) and height (NPH diff=5.33) greater than the Brazilian skulls, and the Scottish mandibles tend to show a higher mandibular ramus height (MRH diff=9.25), a higher mandibular body height (HMB diff=6.37) and a larger bigonial breadth (BGB diff=5.29) than the Brazilians. The discriminant analysis of the 51 cranial measurements and 21 mandibular measurements showed a variation of the percentage of accuracy between 46.3- 83.8%. Conclusion: The metric analysis demonstrated that there is variability between the two samples studied (61.11%), but a concrete cause cannot be determined considering the multifactorial aspects of the variations of form and size
The accuracy of diagnostic coding for acute kidney injury in England - A single centre study
This is the final version. Available on open access from BMC via the DOI in this recordBackground: Acute kidney injury (AKI) is an independent risk factor for mortality and is responsible for a significant burden of healthcare expenditure, so accurate measurement of its incidence is important. Administrative coding data has been used for assessing AKI incidence, and shows an increasing proportion of hospital bed days attributable to AKI. However, the accuracy of coding for AKI and changes in coding over time have not been studied in England. Methods. We studied a random sample of admissions from 2005 and 2010 where ICD-10 code N17 (acute renal failure) was recorded in the administrative coding data at one acute NHS Foundation Trust in England. Using the medical notes and computerised records we examined the demographic and clinical details of these admissions. Results: Against a 6.3% (95% CI 4.8-7.9%) increase in all non-elective admissions, we found a 64% increase in acute renal failure admissions (95% CI 41%-92%, p<0.001) in 2010 compared to 2005. Median age was 78 years (IQR 72-87), 11-25% had a relevant pre-admission co-morbidity and 64% (55-73%) were taking drugs known to be associated with AKI. Over both years, 95% (91-99%) of cases examined met the Kidney Disease: Improving Global Outcomes criteria for AKI. Conclusions: Patients with hospital admissions where AKI has been coded are elderly with multiple co-morbidities. Our results demonstrate a high positive predictive value of coding data for a clinical diagnosis of AKI, with no suggestion of marked changes in coding of AKI between 2005 and 2010. © 2013 Tomlinson et al; licensee BioMed Central Ltd.Cambridge Biomedical Research InstituteBritish Heart Foundatio
A re-appraisal of the reliability of the 20 m multi-stage shuttle run test
This is the author's PDF version of an article published in European journal of applied physiology in 2007. The original publication is available at www.springerlink.co
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