Asteroseismology

Asteroseismology is the determination of the interior structures of stars by using their oscillations as seismic waves. Simple explanations of the astrophysical background and some basic theoretical considerations needed in this rapidly evolving field are followed by introductions to the most important concepts and methods on the basis of example. Previous and potential applications of asteroseismology are reviewed and future trends are attempted to be foreseen.Comment: 38 pages, 13 figures, to appear in: "Planets, Stars and Stellar Systems", eds. T. D. Oswalt et al., Springer Verla

Trends in postoperative radiotherapy delay and the effect on survival in breast cancer patients treated with conservation surgery

The adequate timing of adjuvant radiotherapy (RT) in breast cancer has become a subject of increasing interest in recent years. A population-based study was undertaken to determine the influence of demographic and clinical factors on the postoperative RT delay in patients treated with breast-conserving surgery (BCS) and to assess the impact of delay on survival. In total, 7800 breast cancer patients treated with BCS and adjuvant RT between 1986 and 1998 in Yorkshire were included in the study. The median interval between surgery and the start of RT (S-RT interval) was 8 weeks (7 weeks for chemotherapy negative and 11 for chemotherapy positive patients). This interval increased substantially over time from 5 weeks during 1986-1988, irrespective of patients' chemotherapy status, to 10 and 17 weeks among chemotherapy negative and chemotherapy positive patients, respectively, in 1997-1998. The S-RT interval was also significantly influenced by travel time to RT centre, year and at which RT centre patient had the treatment (

A population-based study of ambulatory and surgical services provided by orthopaedic surgeons for musculoskeletal conditions

<p>Abstract</p> <p>Background</p> <p>The ongoing process of population aging is associated with an increase in prevalence of musculoskeletal conditions with a concomitant increase in the demand of orthopaedic services. Shortages of orthopaedic services have been documented in Canada and elsewhere. This population-based study describes the number of patients seen by orthopaedic surgeons in office and hospital settings to set the scene for the development of strategies that could maximize the availability of orthopaedic resources.</p> <p>Methods</p> <p>Administrative data from the Ontario Health Insurance Plan and Canadian Institute for Health Information hospital separation databases for the 2005/06 fiscal year were used to identify individuals accessing orthopaedic services in Ontario, Canada. The number of patients with encounters with orthopaedic surgeons, the number of encounters and the number of surgeries carried out by orthopaedic surgeons were estimated according to condition groups, service location, patient's age and sex.</p> <p>Results</p> <p>In 2005/06, over 520,000 Ontarians (41 per 1,000 population) had over 1.3 million encounters with orthopaedic surgeons. Of those 86% were ambulatory encounters and 14% were in hospital encounters. The majority of ambulatory encounters were for an injury or related condition (44%) followed by arthritis and related conditions (37%). Osteoarthritis accounted for 16% of all ambulatory encounters. Orthopaedic surgeons carried out over 140,000 surgeries in 2005/06: joint replacement accounted for 25% of all orthopaedic surgeries, whereas closed repair accounted for 16% and reductions accounted for 21%. Half of the orthopaedic surgeries were for arthritis and related conditions.</p> <p>Conclusion</p> <p>The large volume of ambulatory care points to the significant contribution of orthopaedic surgeons to the medical management of chronic musculoskeletal conditions including arthritis and injuries. The findings highlight that surgery is only one component of the work of orthopaedic surgeons in the management of these conditions. Policy makers and orthopaedic surgeons need to be creative in developing strategies to accommodate the growing workload of orthopaedic surgeons without sacrificing quality of care of patients with musculoskeletal conditions.</p

The accuracy of the report of hepatic steatosis on ultrasonography in patients infected with hepatitis C in a clinical setting: A retrospective observational study

BACKGROUND: Steatosis is occasionally reported during screening ultrasonography in patients with hepatitis C virus (HCV). We conducted a retrospective observational study to assess the factors associated with steatosis on ultrasonography and the relationship between steatosis on ultrasound versus biopsy in patients infected with HCV in a clinical setting. Our hypothesis was ultrasonography would perform poorly for the detection of steatosis outside of the context of a controlled study, primarily due to false-positive results caused by hepatic fibrosis and inflammation. METHODS: A retrospective review of ultrasound reports was conducted on patients infected with HCV in a tertiary care gastroenterology clinic. Reports were reviewed for the specific documentation of the presence of steatosis. Baseline clinical and histologic parameters were recorded, and compared for patients with vs. without steatosis. Multiple logistic regression analysis was performed on these baseline variables. Liver biopsies were reviewed by two pathologists, and graded for steatosis. Steatosis on biopsy was compared to steatosis on ultrasound report, and the performance characteristics of ultrasonography were calculated, using biopsy as the gold standard. RESULTS: Ultrasound reports were available on 164 patients. Patients with steatosis on ultrasound had a higher incidence of the following parameters compared to patients without steatosis: diabetes (12/49 [24%] vs. 7/115 [6%], p < 0.001), fibrosis stage >2 (15/48 [31%] vs. 16/110 [15%], p = 0.02), histologic grade >2 (19/48 [40%] vs. 17/103 [17%], p = 0.002), and ALT (129.5 ± 89.0 IU/L vs. 94.3 ± 87.0 IU/L, p = 0.01). Histologic grade was the only factor independently associated with steatosis with multivariate analysis. When compared to the histologic diagnosis of steatosis (n = 122), ultrasonography had a substantial number of false-positive and false-negative results. In patients with a normal ultrasound, 8/82 (10%) had >30% steatosis on biopsy. Among patients with steatosis reported on ultrasound, only 12/40 (30%) had >30% steatosis on biopsy review. CONCLUSION: Steatosis on ultrasound is associated with markers of inflammation and fibrosis in HCV-infected patients, but does not consistently correlate with steatosis on biopsy outside of the context of a controlled study. Clinicians should be skeptical of the definitive diagnosis of steatosis on hepatic ultrasonography

Asteroseismology and Interferometry

Asteroseismology provides us with a unique opportunity to improve our understanding of stellar structure and evolution. Recent developments, including the first systematic studies of solar-like pulsators, have boosted the impact of this field of research within Astrophysics and have led to a significant increase in the size of the research community. In the present paper we start by reviewing the basic observational and theoretical properties of classical and solar-like pulsators and present results from some of the most recent and outstanding studies of these stars. We centre our review on those classes of pulsators for which interferometric studies are expected to provide a significant input. We discuss current limitations to asteroseismic studies, including difficulties in mode identification and in the accurate determination of global parameters of pulsating stars, and, after a brief review of those aspects of interferometry that are most relevant in this context, anticipate how interferometric observations may contribute to overcome these limitations. Moreover, we present results of recent pilot studies of pulsating stars involving both asteroseismic and interferometric constraints and look into the future, summarizing ongoing efforts concerning the development of future instruments and satellite missions which are expected to have an impact in this field of research.Comment: Version as published in The Astronomy and Astrophysics Review, Volume 14, Issue 3-4, pp. 217-36

Epidemiology of Knee and Hip Arthroplasty: A Systematic Review§

We present a systematic review of epidemiologic studies of Total Knee Arthroplasty (TKA) and Total Hip Arthroplasty (THA). The studies summarized in this systematic review provide us with estimates of arthroplasty utilization rates, underlying disease frequency and its trends and differences in utilization rates by age, gender and ethnicity among other factors. Among these, many studies are registry-based that assessed utilization rates using data from major orthopedic centers that may provide some understanding of underlying diagnosis and possibly time-trends. Several studies are population-based cross-sectional, which provide estimates of prevalence of TKA and THA. Population-based cohort studies included in this review provide the best estimates of incidence and utilization rates, time-trends and differences in these rates by important patient characteristics (age, gender, ethnicity and others). This article reviews the current published literature in the area and highlights the main findings

Trends in incidence and outcomes of revision total hip arthroplasty in Spain: A population based study

<p>Abstract</p> <p>Background</p> <p>To analyze changes in incidence and outcomes of patients undergoing revision total hip arthroplasty (RTHA) over an 8-year study period in Spain.</p> <p>Methods</p> <p>We selected all surgical admissions in individuals aged ≥ 40 years who underwent RTHA (ICD-9-CM procedure code 81.53) between 2001 and 2008 from the Spanish National Hospital Discharge Database. Age- and sex-specific incidence rates, Charlson co-morbidity index, length of stay (LOS), costs and in-hospital mortality (IHM) were estimated for each year. Multivariate analyses were conducted to asses time trends.</p> <p>Results</p> <p>32, 280 discharges of patients (13, 391 men/18, 889 women) having undergone RTHA were identified. Overall crude incidence showed a small but significant increase from 20.2 to 21.8 RTHA per 100, 000 inhabitants from 2001 to 2008 (p < 0.01).</p> <p>The incidence increased for men (17.7 to 19.8 in 2008) but did not vary for women (22.3 in 2001 and 22.2 in 2008). Greater increments were observed in patients older than 84 years and in the age group 75-84. In 2001, 19% of RTHA patients had a Charlson Index ≥ 1 and this proportion rose to 24.6% in 2008 (p < 0.001). The ratio RTHA/THA remained stable and around 20% in Spain along the entire period</p> <p>The crude overall in-hospital mortality (IHM) increased from 1.16% in 2001 to 1.77% (p = 0.025) in 2008. For both sexes the risk of death was higher with age, with the highest mortality rates found among those aged 85 or over. After multivariate analysis no change was observed in IHM over time. The mean inflation adjusted cost per patient increased by 78.3%, from 9, 375 to 16, 715 Euros from 2001 to 2008.</p> <p>After controlling for possible confounders using Poisson regression models, we observed that the incidence of RTHA hospitalizations significantly increased for men and women over the period 2001 to 2008 (IRR 1.10, 95% CI 1.03-1.18 and 1.08, 95% CI 1.02-1.14 respectively).</p> <p>Conclusions</p> <p>The crude incidence of RTHA in Spain showed a small but significant increase from 2001 to 2008 with concomitant reductions in LOS, significant increase in co-morbidities and cost per patient.</p

Oral Thromboprophylaxis Following Total Hip or Knee Replacement: Review and Multicentre Experience with Dabigatran Etexilate

The risk of venous thromboembolism (VTE) in patients undergoing total knee or hip replacement surgery is high. As a result, thromboprophylaxis is highly recommended. While current thromboprophylactic agents, such as low molecular weight heparins (LMWH) and vitamin K antagonists, are safe and effective their use can be problematic. Therefore, there is a need for alternative anticoagulants that are as safe and effective as conventional agents, but are more convenient and easier to use. Dabigatran etexilate, a direct thrombin inhibitor, is one such anticoagulant. For VTE prevention following major orthopaedic surgery, dabigatran etexilate shows similar efficacy and safety to the LMWH enoxaparin, and is approved for use in more than 75 countries, including Europe and Canada. Here, we summarize and discuss the experiences of four German clinics that have recently introduced dabigatran etexilate into clinical practice. Overall, dabigatran etexilate was well received by patients, surgeons and nurses, and compared favourably with enoxaparin. Staff appreciated the oral, single-dose administration of dabigatran etexilate. Patient satisfaction was high, especially in those individuals who had previously used LMWHs. In this review, we also address a number of questions that were asked by patients or staff; this will be of relevance to orthopaedic surgeons and nurses. We conclude that, in these four German clinics, dabigatran etexilate offered an effective oral alternative to existing thromboprophylactic agents in patients undergoing major orthopaedic surgery

Efficient oligonucleotide probe selection for pan-genomic tiling arrays

Background: Array comparative genomic hybridization is a fast and cost-effective method for detecting, genotyping, and comparing the genomic sequence of unknown bacterial isolates. This method, as with all microarray applications, requires adequate coverage of probes targeting the regions of interest. An unbiased tiling of probes across the entire length of the genome is the most flexible design approach. However, such a whole-genome tiling requires that the genome sequence is known in advance. For the accurate analysis of uncharacterized bacteria, an array must query a fully representative set of sequences from the species' pan-genome. Prior microarrays have included only a single strain per array or the conserved sequences of gene families. These arrays omit potentially important genes and sequence variants from the pan-genome. Results: This paper presents a new probe selection algorithm (PanArray) that can tile multiple whole genomes using a minimal number of probes. Unlike arrays built on clustered gene families, PanArray uses an unbiased, probe-centric approach that does not rely on annotations, gene clustering, or multi-alignments. Instead, probes are evenly tiled across all sequences of the pangenome at a consistent level of coverage. To minimize the required number of probes, probes conserved across multiple strains in the pan-genome are selected first, and additional probes are used only where necessary to span polymorphic regions of the genome. The viability of the algorithm is demonstrated by array designs for seven different bacterial pan-genomes and, in particular, the design of a 385,000 probe array that fully tiles the genomes of 20 different Listeria monocytogenes strains with overlapping probes at greater than twofold coverage. Conclusion: PanArray is an oligonucleotide probe selection algorithm for tiling multiple genome sequences using a minimal number of probes. It is capable of fully tiling all genomes of a species on a single microarray chip. These unique pan-genome tiling arrays provide maximum flexibility for the analysis of both known and uncharacterized strains.https://doi.org/10.1186/1471-2105-10-29

Breaking bad habits by improving executive function in individuals with obesity

Background: Two primary factors that contribute to obesity are unhealthy eating and sedentary behavior. These behaviors are particularly difficult to change in the long-term because they are often enacted habitually. Cognitive Remediation Therapy has been modified and applied to the treatment of obesity (CRT-O) with preliminary results of a randomized controlled trial demonstrating significant weight loss and improvements in executive function. The objective of this study was to conduct a secondary data analysis of the CRT-O trial to evaluate whether CRT-O reduces unhealthy habits that contribute to obesity via improvements in executive function. Method: Eighty participants with obesity were randomized to CRT-O or control. Measures of executive function (Wisconsin Card Sort Task and Trail Making Task) and unhealthy eating and sedentary behavior habits were administered at baseline, post-intervention and at 3 month follow-up. Results: Participants receiving CRT-O demonstrated improvements in both measures of executive function and reductions in both unhealthy habit outcomes compared to control. Mediation analyses revealed that change in one element of executive function performance (Wisconsin Card Sort Task perseverance errors) mediated the effect of CRT-O on changes in both habit outcomes. Conclusion: These results suggest that the effectiveness of CRT-O may result from the disruption of unhealthy habits made possible by improvements in executive function. In particular, it appears that cognitive flexibil ity, as measured by the Wisconsin Card Sort task, is a key mechanism in this process. Improving cognitive flexibility may enable individuals to capitalise on interruptions in unhealthy habits by adjusting their behavior in line with their weight loss goals rather than persisting with an unhealthy choice. Trial registration: The RCT was registered with the Australian New Zealand Registry of Clinical Trials (trial id: ACTRN12613000537752)