RESUMO
Attempts to understand the molecular structure of water were first made well over a century ago. Looking back at the various attempts, it is illuminating to see how these were conditioned by the state of knowledge of chemistry and physics at the time and the experimental and theoretical tools then available. Progress in the intervening years has been facilitated by not only conceptual and theoretical advances in physics and chemistry but also the development of experimental techniques and instrumentation. Exploitation of powerful computational methods in interpreting what at first sight may seem impenetrable experimental data has led us to the consistent and detailed picture we have today of not only the structure of liquid water itself and how it changes with temperature and pressure but also its interactions with other molecules, in particular those relevant to water's role in important chemical and biological processes. Much remains to be done in the latter areas, but the experimental and computational techniques that now enable us to do what might reasonably be termed "liquid state crystallography" have opened the door to make possible further advances. Consequently, we now have the tools to explore further the role of water in those processes that underpin life itself-the very prospect that inspired Bernal to develop his ideas on the structure of liquids in general and of water in particular.
RESUMO
Ice V is a structurally highly complex material with 28 water molecules in its monoclinic unit cell. It is classified as a hydrogen-disordered phase of ice. Yet, some of its hydrogen-bonded water molecules display significant orientational order. Upon cooling pure ice V, additional orientational ordering cannot be achieved on the experimental time scale. Doping with hydrochloric acid has been shown to be most effective in enabling the phase transition of ice V to its hydrogen-ordered counterpart ice XIII. Here, we present a detailed crystallographic study of this phase transition investigating the effects of hydrochloric and hydrofluoric acid as well as lithium and potassium hydroxide doping. The magnitudes of the stepwise changes in the lattice constants during the phase transition are found to be more sensitive indicators for the extent of hydrogen order in ice XIII than the appearance of new Bragg peaks. Hydrofluoric acid and lithium hydroxide doping enable similar ordering processes as hydrochloric acid but with slower kinetics. The various possible space groups and ordered configurations of ice XIII are examined systematically, and the previously determined P21/a structure is confirmed. Interestingly, the partial hydrogen order already present in ice V is found to perpetuate into ice XIII, and these ordering processes are found to be independent of pressure. Overall, the hydrogen ordering goes along with a small increase in volume, which appears to be the origin of the slower hydrogen-ordering kinetics under pressure. Heating pressure-quenched samples at ambient pressure revealed low-temperature "transient ordering" features in both diffraction and calorimetry.
RESUMO
OBJECTIVE: To determine the influence of bariatric surgery on remission of type 2 diabetes mellitus (T2DM) in obese patients along with improvements in other obesity-associated comorbidities. STUDY DESIGN: Observational study. PLACE AND DURATION OF STUDY: Doncaster and Bassetlaw NHS Trust, UK, from August 2010 to August 2018. METHODOLOGY: All the cases of bariatric surgery in obese patients with T2DM who had completed 2 years of follow up were included in the study. Remission of T2DM was defined as glycated hemoglobin (HbA1C) <48 mmol/mol (<6.5%) or fasting blood sugar of <7.0 mmol/L, not on hypoglycemic agents 2 years after having bariatric surgery. Student's t-test was used to see any difference in baseline HbA1C, BMI, percentage of weight loss, and duration of diabetes between remitters and non-remitters. RESULTS: Two years follow-up data after bariatric surgery for remission of T2DM or otherwise was available for (n=121) patients. Majority (70.2%, n=85) were females and (29.8%, n=36) were males. Mean age was 48.21 ±9.77 years. Eightythree (68.6%) patients achieved remission of T2DM at 2 years and 31.4% (n=38) did not. Remission of other comorbidities was 33.3% (n=53 out of 159) for hypertension (HTN), 50.8% (n=60 out of 118) for dyslipidemia, 67.2% (n=43 out of 64) for obstructive sleep apnea (OSA), 52.1% (n=37 out of 71) for gastro esophageal reflux disease (GERD), 25.7% (n=18 out of 70) for asthma, and 23.3% (n=24 out of 103) for depression. CONCLUSION: Bariatric surgery effectively achieves remission of T2DM and other obesity associated comorbidities.
Assuntos
Cirurgia Bariátrica , Diabetes Mellitus Tipo 2/prevenção & controle , Obesidade Mórbida/cirurgia , Biomarcadores/sangue , Inglaterra , Feminino , Humanos , Masculino , Pessoa de Meia-IdadeRESUMO
BACKGROUND: The prevalence of obstructive sleep apnoea (OSA) in the bariatric population has been reported to be as high as 60-83%. The Epworth Sleepiness Scale (ESS) is a validated, self-administrated eight-item questionnaire that measures subjective daytime sleepiness and thus helps to identify high-risk for OSA. OBJECTIVES: To find the prevalence of OSA in patients undergoing bariatric surgery who do not routinely undergo polysomnography (PSG) and are screened by the ESS. METHODS: All consecutive 425 patients who underwent bariatric surgery in our tercier referral centre from January 2012 to June 2017 were included in this prospective study. Patient demographics and ESS score were recorded prior to the bariatric surgery and patients were divided into low-risk (ESS < 11), high-risk (≥ 11) and "known-OSA" groups. RESULTS: The community-based OSA prevalence was 14% (59 patients). ESS-positive predictive value was 60%. There was no significant difference in BMI and excess body-weight, but patients with OSA were older and had a lower female ratio (75% vs 42%). The unplanned ICU admission rate was comparable amongst the low- and high-ESS group (2.2% and 2.1%, respectively); similarly, the respiratory and chest complication rate were similar. The median hospital stay for patients diagnosed with OSA was a half day longer; the high-score patients stayed significantly longer than the low-score patients (p = 0.017). CONCLUSION: In our study, the OSA prevalence was low (20%). We think that the ESS does not have significant predicting value before bariatric surgery and overall the OSA is "overhyped" in the bariatric pathway.
Assuntos
Cirurgia Bariátrica/estatística & dados numéricos , Cuidados Pré-Operatórios/métodos , Apneia Obstrutiva do Sono/diagnóstico , Apneia Obstrutiva do Sono/epidemiologia , Humanos , Obesidade Mórbida/cirurgia , Prevalência , Estudos Prospectivos , Inquéritos e QuestionáriosRESUMO
OBJECTIVE: In recent years, a shift has occurred from identifying variables that mediate the effects of psychosocial interventions for problematic alcohol use to trying to identify effective mechanisms of behavior change (MOBCs) that lead to better drinking-related and other outcomes. Although implementing interventions targeting specific MOBCs has considerable conceptual and intuitive appeal, it is important that strong empirical evidence be available that supports such implementation. One aim of this article is to consider some prior mediational analyses of the effects of alcohol-focused psychosocial treatments to illustrate findings and the types of evidence that typically have been presented. A second aim is to consider methodological approaches, specifically certain statistical analyses of observational data and experimental designs, that could provide more rigorous evidence regarding the causal effects of mechanisms of change (mediators) in producing desired drinking-related outcomes. RESULTS: Prior analyses that have examined the association of a mediator with an outcome, or the relationship between a mediator and an outcome with assigned treatment controlled, do not provide strong evidence regarding the causal effects of mediators on outcomes. Unfortunately, experimental designs that directly manipulate mediators seem difficult to apply in the alcohol treatment field as an approach to examine mediator/MOBC effects. CONCLUSION: To produce more compelling evidence, we need to investigate interventions that target a specific MOBC and then capitalize on random assignment to intervention/control conditions by using principal stratification or instrumental variable analyses to identify the effects of intervention-induced mediator change on outcomes.
Assuntos
Alcoolismo/terapia , Meditação , Alcoolismo/psicologia , Humanos , Projetos de PesquisaRESUMO
BACKGROUND: Approximately 30-40% of children <1 year of age are Clostridium difficile colonized, and may represent a reservoir for adult C. difficile infections (CDI). Risk factors for colonization with toxigenic versus non-toxigenic C. difficile strains and longitudinal acquisition dynamics in infants remain incompletely characterized. METHODS: Predominantly healthy infants (≤2 years) were recruited in Oxfordshire, UK, and provided ≥1 fecal samples. Independent risk factors for toxigenic/non-toxigenic C. difficile colonization and acquisition were identified using multivariable regression. Infant C. difficile isolates were whole-genome sequenced to assay genetic diversity and prevalence of toxin-associated genes, and compared with sequenced strains from Oxfordshire CDI cases. RESULTS: 338/365 enrolled infants provided 1332 fecal samples, representing 158 C. difficile colonization or carriage episodes (107[68%] toxigenic). Initial colonization was associated with age, and reduced with breastfeeding but increased with pet dogs. Acquisition was associated with older age, Caesarean delivery, and diarrhea. Breastfeeding and pre-existing C. difficile colonization reduced acquisition risk. Overall 13% of CDI C. difficile strains were genetically related to infant strains. 29(18%) infant C. difficile sequences were consistent with recent direct/indirect transmission to/from Oxfordshire CDI cases (≤2 single nucleotide variants [SNVs]); 79(50%) shared a common origin with an Oxfordshire CDI case within the last ~5 years (0-10 SNVs). The hypervirulent, epidemic ST1/ribotype 027 remained notably absent in infants in this large study, as did other lineages such as STs 10/44 (ribotype 015); the most common strain in infants was ST2 (ribotype 020/014)(22%). CONCLUSIONS: In predominantly healthy infants without significant healthcare exposure C. difficile colonization and acquisition reflect environmental exposures, with pet dogs identified as a novel risk factor. Genetic overlap between some infant strains and those isolated from CDI cases suggest common community reservoirs of these C. difficile lineages, contrasting with those lineages found only in CDI cases, and therefore more consistent with healthcare-associated spread.
Assuntos
Clostridioides difficile/genética , Infecções por Clostridium/epidemiologia , Infecções por Clostridium/microbiologia , Portador Sadio/epidemiologia , Clostridioides difficile/classificação , Análise por Conglomerados , Infecção Hospitalar/epidemiologia , Infecção Hospitalar/microbiologia , DNA Bacteriano , Diarreia/epidemiologia , Diarreia/microbiologia , Evolução Molecular , Fezes/microbiologia , Feminino , Variação Genética , Humanos , Lactente , Recém-Nascido , Masculino , Prevalência , Fatores de Risco , Análise de Sequência de DNA , Reino Unido/epidemiologiaRESUMO
BACKGROUND: Weekend hospital admission is associated with increased mortality, but the contributions of varying illness severity and admission time to this weekend effect remain unexplored. METHODS: We analysed unselected emergency admissions to four Oxford University National Health Service hospitals in the UK from Jan 1, 2006, to Dec 31, 2014. The primary outcome was death within 30 days of admission (in or out of hospital), analysed using Cox models measuring time from admission. The primary exposure was day of the week of admission. We adjusted for multiple confounders including demographics, comorbidities, and admission characteristics, incorporating non-linearity and interactions. Models then considered the effect of adjusting for 15 common haematology and biochemistry test results or proxies for hospital workload. FINDINGS: 257â596 individuals underwent 503â938 emergency admissions. 18â313 (4·7%) patients admitted as weekday energency admissions and 6070 (5·1%) patients admitted as weekend emergency admissions died within 30 days (p<0·0001). 9347 individuals underwent 9707 emergency admissions on public holidays. 559 (5·8%) died within 30 days (p<0·0001 vs weekday). 15 routine haematology and biochemistry test results were highly prognostic for mortality. In 271â465 (53·9%) admissions with complete data, adjustment for test results explained 33% (95% CI 21 to 70) of the excess mortality associated with emergency admission on Saturdays compared with Wednesdays, 52% (lower 95% CI 34) on Sundays, and 87% (lower 95% CI 45) on public holidays after adjustment for standard patient characteristics. Excess mortality was predominantly restricted to admissions between 1100 h and 1500 h (pinteraction=0·04). No hospital workload measure was independently associated with mortality (all p values >0·06). INTERPRETATION: Adjustment for routine test results substantially reduced excess mortality associated with emergency admission at weekends and public holidays. Adjustment for patient-level factors not available in our study might further reduce the residual excess mortality, particularly as this clustered around midday at weekends. Hospital workload was not associated with mortality. Together, these findings suggest that the weekend effect arises from patient-level differences at admission rather than reduced hospital staffing or services. FUNDING: NIHR Oxford Biomedical Research Centre.
Assuntos
Plantão Médico/estatística & dados numéricos , Hospitalização/estatística & dados numéricos , Mortalidade , Admissão do Paciente/estatística & dados numéricos , Adulto , Idoso , Idoso de 80 Anos ou mais , Grupos Diagnósticos Relacionados/estatística & dados numéricos , Registros Eletrônicos de Saúde , Emergências , Inglaterra/epidemiologia , Feminino , Férias e Feriados , Mortalidade Hospitalar , Humanos , Masculino , Pessoa de Meia-Idade , Modelos de Riscos Proporcionais , Medição de Risco/métodos , Medicina Estatal/estatística & dados numéricosRESUMO
PURPOSE: The purpose of this paper is to study the causes of leaks following sleeve gastrectomy (SG). MATERIALS AND METHODS: Pubmed was searched during January 2016 for publications reporting leak after SG. A total of 205 publications were identified, of which 17 papers were selected. RESULTS: In about 3018 patients, reinforcement was used compared with 4595 patients, in whom no reinforcement was applied; both groups were representing matched bariatric populations. The use of reinforcement/buttressing has resulted in different rates of leaks ranging from 0% to 3.9%; whereas with no reinforcement/buttressing, the leak rate was 0.16% to 3.5%. The use of reinforcement/buttressing did not result in reduction of leak to a statistical significance although the trend was suggesting so (P=0.06), whereas no reinforcement/buttressing did not statistically increase the leak rate (P=0.10). CONCLUSIONS: No statistical significant difference of leak with or without reinforcement. This mean case complexity and surgical technique and experience are the sole factors for leaks following SG.
Assuntos
Cirurgia Bariátrica/efeitos adversos , Gastrectomia/efeitos adversos , Laparoscopia/efeitos adversos , Fístula Anastomótica/etiologia , Cirurgia Bariátrica/métodos , Gastrectomia/métodos , Humanos , Laparoscopia/métodosRESUMO
OBJECTIVES: Care coordination for substance use disorder (SUD) treatment is a persistent challenge. Timely outpatient follow-up after detoxification from alcohol and opiates is associated with improved outcomes, leading some care systems to attempt to measure and incentivize this practice. This study evaluated the predictive validity of a 7-day outpatient follow-up after detoxification quality measure used by the Veterans Health Administration (VHA). METHODS: A national sample of patients who received detoxification from alcohol or opiates (Nâ=â25,354) was identified in VHA administrative data. Propensity score-weighted mixed-effects regressions modeled associations between receiving an outpatient follow-up visit within 7 days of completing detoxification and patient outcomes, controlling for facility-level performance and clustering of patients within facilities. RESULTS: Baseline differences between patients who did (39.6%) and did not (60.4%) receive the follow-up visit were reduced or eliminated with propensity score weighting. Meeting the quality measure was associated with significantly more outpatient treatment for SUD (bâ=â1.07 visits) and other mental health conditions (bâ=â0.58 visits), and higher inpatient utilization for SUD (bâ=â0.75 admissions) and other mental health conditions (bâ=â0.76 admissions). Notably, meeting the quality measure was associated with 53.3% lower odds of 2-year mortality (Pâ<â0.001 for all). CONCLUSIONS: These findings support the predictive validity of 7-day follow-up after detoxification as a care coordination measure. Well-coordinated care may be associated with higher outpatient and inpatient utilization, and such engagement in care may be protective against mortality in people who receive detoxification from alcohol or opiates.
Assuntos
Assistência ao Convalescente/estatística & dados numéricos , Transtornos Relacionados ao Uso de Álcool/terapia , Assistência Ambulatorial/estatística & dados numéricos , Continuidade da Assistência ao Paciente/normas , Transtornos Relacionados ao Uso de Opioides/terapia , Garantia da Qualidade dos Cuidados de Saúde/métodos , Indicadores de Qualidade em Assistência à Saúde/estatística & dados numéricos , Adulto , Assistência ao Convalescente/normas , Idoso , Assistência Ambulatorial/normas , Continuidade da Assistência ao Paciente/estatística & dados numéricos , Feminino , Seguimentos , Humanos , Masculino , Pessoa de Meia-Idade , Pontuação de Propensão , Análise de Regressão , Reprodutibilidade dos Testes , Resultado do Tratamento , Estados Unidos , United States Department of Veterans AffairsRESUMO
PURPOSE: Limited empirical attention to date has focused on best practices in advanced research mentoring in the health services research domain. The authors investigated whether institutional incentives for mentoring (e.g., consideration of mentoring in promotion criteria) were associated with mentors' perceptions of mentoring benefits and costs and with time spent mentoring. METHOD: The authors conducted an online survey in 2014 of a national sample of mentors of U.S. Department of Veterans Affairs (VA) Health Services Research and Development Service (HSR&D) mentored career development award recipients who received an award during 2000-2012. Regression analyses were used to examine institutional incentives as predictors of perceptions of benefits and costs of mentoring and time spent mentoring. RESULTS: Of the 145 mentors invited, 119 (82%) responded and 110 (76%) provided complete data for the study items. Overall, mentors who reported more institutional incentives also reported greater perceived benefits of mentoring (P = .03); however, more incentives were not significantly associated with perceived costs of mentoring. Mentors who reported more institutional incentives also reported spending a greater percentage of time mentoring (P = .02). University incentives were associated with perceived benefits of mentoring (P = .02), whereas VA incentives were associated with time spent mentoring (P = .003). CONCLUSIONS: Institutional policies that promote and support mentorship of junior investigators, specifically by recognizing and rewarding the efforts of mentors, are integral to fostering mentorship programs that contribute to the development of early-career health services researchers into independent investigators.
Assuntos
Docentes de Medicina , Pesquisa sobre Serviços de Saúde , Tutoria , Mentores , Motivação , Pesquisadores , Atitude do Pessoal de Saúde , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Inquéritos e Questionários , Fatores de Tempo , Estados Unidos , United States Department of Veterans Affairs , UniversidadesRESUMO
BACKGROUND: The control of Clostridium difficile infections is an international clinical challenge. The incidence of C difficile in England declined by roughly 80% after 2006, following the implementation of national control policies; we tested two hypotheses to investigate their role in this decline. First, if C difficile infection declines in England were driven by reductions in use of particular antibiotics, then incidence of C difficile infections caused by resistant isolates should decline faster than that caused by susceptible isolates across multiple genotypes. Second, if C difficile infection declines were driven by improvements in hospital infection control, then transmitted (secondary) cases should decline regardless of susceptibility. METHODS: Regional (Oxfordshire and Leeds, UK) and national data for the incidence of C difficile infections and antimicrobial prescribing data (1998-2014) were combined with whole genome sequences from 4045 national and international C difficile isolates. Genotype (multilocus sequence type) and fluoroquinolone susceptibility were determined from whole genome sequences. The incidence of C difficile infections caused by fluoroquinolone-resistant and fluoroquinolone-susceptible isolates was estimated with negative-binomial regression, overall and per genotype. Selection and transmission were investigated with phylogenetic analyses. FINDINGS: National fluoroquinolone and cephalosporin prescribing correlated highly with incidence of C difficile infections (cross-correlations >0·88), by contrast with total antibiotic prescribing (cross-correlations <0·59). Regionally, C difficile decline was driven by elimination of fluoroquinolone-resistant isolates (approximately 67% of Oxfordshire infections in September, 2006, falling to approximately 3% in February, 2013; annual incidence rate ratio 0·52, 95% CI 0·48-0·56 vs fluoroquinolone-susceptible isolates: 1·02, 0·97-1·08). C difficile infections caused by fluoroquinolone-resistant isolates declined in four distinct genotypes (p<0·01). The regions of phylogenies containing fluoroquinolone-resistant isolates were short-branched and geographically structured, consistent with selection and rapid transmission. The importance of fluoroquinolone restriction over infection control was shown by significant declines in inferred secondary (transmitted) cases caused by fluoroquinolone-resistant isolates with or without hospital contact (p<0·0001) versus no change in either group of cases caused by fluoroquinolone-susceptible isolates (p>0·2). INTERPRETATION: Restricting fluoroquinolone prescribing appears to explain the decline in incidence of C difficile infections, above other measures, in Oxfordshire and Leeds, England. Antimicrobial stewardship should be a central component of C difficile infection control programmes. FUNDING: UK Clinical Research Collaboration (Medical Research Council, Wellcome Trust, National Institute for Health Research); NIHR Oxford Biomedical Research Centre; NIHR Health Protection Research Unit on Healthcare Associated Infection and Antimicrobial Resistance (Oxford University in partnership with Public Health England [PHE]), and on Modelling Methodology (Imperial College, London in partnership with PHE); and the Health Innovation Challenge Fund.
Assuntos
Clostridioides difficile/genética , Infecções por Clostridium/epidemiologia , Infecção Hospitalar/prevenção & controle , Controle de Infecções/métodos , Antibacterianos/uso terapêutico , Clostridioides difficile/isolamento & purificação , Infecções por Clostridium/microbiologia , Infecções por Clostridium/transmissão , Inglaterra/epidemiologia , Fluoroquinolonas/provisão & distribuição , Fluoroquinolonas/uso terapêutico , Estudo de Associação Genômica Ampla , Humanos , Incidência , Tipagem de Sequências Multilocus/métodosRESUMO
BACKGROUND: Measures of substance use disorder (SUD) treatment quality are essential tools for performance improvement. The Veterans Health Administration (VHA) developed a measure of access to and engagement in intensive outpatient programs (IOPs) for SUD. However, predictive validity, or associations between this measure and treatment outcomes, has not been examined. METHODS: Data on veterans with SUD came from 3 samples: the Outcomes Monitoring Project (N = 5436), a national evaluation of VHA mental health services (N = 339,887), and patients receiving detoxification services (N = 23,572). Propensity score-weighted mixed-effects regressions modeled associations between receiving at least 1 week of IOP treatment and patient outcomes, controlling for facility-level performance and a random effect for facility. RESULTS: Propensity score weighting reduced or eliminated observable baseline differences between patient groups. Patients who accessed IOPs versus those who did not reported significantly reduced alcohol- and drug-related symptom severity, with significantly fewer past-month days drinking alcohol (b = 1.83, P < .001) and fewer past-month days intoxicated (b = 1.55, P < .001). Patients who received IOP after detoxification services had higher 6-month utilization of SUD outpatient visits (b = 2.09, P < .001), more subsequent detoxification episodes (b = 0.25, P < .001), and lower odds of 2-year mortality (odds ratio [OR] = 0.68, 95% confidence interval [CI]: 0.61-0.75; P < .001). CONCLUSIONS: Receiving at least 1 week of SUD treatment in an IOP was associated with higher follow-up utilization, improved health outcomes, and reduced mortality. These associations lend support to the predictive validity of VHA's IOP quality measure. Future research should focus on measure feasibility and validity outside of VHA, and whether predictive validity is maintained once this quality measure is tied to performance incentives.
Assuntos
Assistência Ambulatorial/estatística & dados numéricos , Serviços de Saúde Mental/estatística & dados numéricos , Aceitação pelo Paciente de Cuidados de Saúde/estatística & dados numéricos , Garantia da Qualidade dos Cuidados de Saúde/métodos , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Reprodutibilidade dos Testes , Transtornos Relacionados ao Uso de Substâncias/terapia , Resultado do Tratamento , Estados Unidos , United States Department of Veterans Affairs , VeteranosRESUMO
Chemotherapy is often administered in openly designed hospital wards, where the possibility of patient-patient social influence on health exists. Previous research found that social relationships influence cancer patient's health; however, we have yet to understand social influence among patients receiving chemotherapy in the hospital. We investigate the influence of co-presence in a chemotherapy ward. We use data on 4,691 cancer patients undergoing chemotherapy in Oxfordshire, United Kingdom who average 59.8 years of age, and 44% are Male. We construct a network of patients where edges exist when patients are co-present in the ward, weighted by both patients' time in the ward. Social influence is based on total weighted co-presence with focal patients' immediate neighbors, considering neighbors' 5-year mortality. Generalized estimating equations evaluated the effect of neighbors' 5-year mortality on focal patient's 5-year mortality. Each 1,000-unit increase in weighted co-presence with a patient who dies within 5 years increases a patient's mortality odds by 42% (ß = 0.357, CI:0.204,0.510). Each 1,000-unit increase in co-presence with a patient surviving 5 years reduces a patient's odds of dying by 30% (ß = -0.344, CI:-0.538,0.149). Our results suggest that social influence occurs in chemotherapy wards, and thus may need to be considered in chemotherapy delivery.
RESUMO
The D2O ice VI to ice XV hydrogen ordering phase transition at ambient pressure is investigated in detail with neutron diffraction. The lattice constants are found to be sensitive indicators for hydrogen ordering. The a and b lattice constants contract whereas a pronounced expansion in c is found upon hydrogen ordering. Overall, the hydrogen ordering transition goes along with a small increase in volume, which explains why the phase transition is more difficult to observe upon cooling under pressure. Slow-cooling ice VI at 1.4 GPa gives essentially fully hydrogen-disordered ice VI. Consistent with earlier studies, the ice XV obtained after slow-cooling at ambient pressure is best described with P-1 space group symmetry. Using a new modelling approach, we achieve the atomistic reconstruction of a supercell structure that is consistent with the average partially ordered structure derived from Rietveld refinements. This shows that C-type networks are most prevalent in ice XV, but other structural motifs outside of the classifications of the fully hydrogen-ordered networks are identified as well. The recently proposed Pmmn structural model for ice XV is found to be incompatible with our diffraction data, and we argue that only structural models that are capable of describing full hydrogen order should be used.
RESUMO
Studies finding weak or nonexistent relationships between hospital performance on providing recommended care and hospital-level clinical outcomes raise questions about the value and validity of process of care performance measures. Such findings may cause clinicians to question the effectiveness of the care process presumably captured by the performance measure. However, one cannot infer from hospital-level results whether patients who received the specified care had comparable, worse or superior outcomes relative to patients not receiving that care. To make such an inference has been labeled the "ecological fallacy," an error that is well known among epidemiologists and sociologists, but less so among health care researchers and policy makers. We discuss such inappropriate inferences in the health care performance measurement field and illustrate how and why process measure-outcome relationships can differ at the patient and hospital levels. We also offer recommendations for appropriate multilevel analyses to evaluate process measure-outcome relationships at the patient and hospital levels and for a more effective role for performance measure bodies and research funding organizations in encouraging such multilevel analyses.
Assuntos
Hospitais/normas , Avaliação de Processos e Resultados em Cuidados de Saúde/normas , Assistência ao Paciente/normas , Indicadores de Qualidade em Assistência à Saúde/normas , Qualidade da Assistência à Saúde/normas , Humanos , Avaliação de Processos e Resultados em Cuidados de Saúde/métodos , Assistência ao Paciente/métodosRESUMO
BACKGROUND: Community-acquired pneumonia (CAP) is a major cause of mortality and morbidity in many countries but few recent large-scale studies have examined trends in its incidence. METHODS: Incidence of CAP leading to hospitalisation in one UK region (Oxfordshire) was calculated over calendar time using routinely collected diagnostic codes, and modelled using piecewise-linear Poisson regression. Further models considered other related diagnoses, typical administrative outcomes, and blood and microbiology test results at admission to determine whether CAP trends could be explained by changes in case-mix, coding practices or admission procedures. RESULTS: CAP increased by 4.2%/year (95% CI 3.6 to 4.8) from 1998 to 2008, and subsequently much faster at 8.8%/year (95% CI 7.8 to 9.7) from 2009 to 2014. Pneumonia-related conditions also increased significantly over this period. Length of stay and 30-day mortality decreased slightly in later years, but the proportions with abnormal neutrophils, urea and C reactive protein (CRP) did not change (p>0.2). The proportion with severely abnormal CRP (>100â mg/L) decreased slightly in later years. Trends were similar in all age groups. Streptococcus pneumoniae was the most common causative organism found; however other organisms, particularly Enterobacteriaceae, increased in incidence over the study period (p<0.001). CONCLUSIONS: Hospitalisations for CAP have been increasing rapidly in Oxfordshire, particularly since 2008. There is little evidence that this is due only to changes in pneumonia coding, an ageing population or patients with substantially less severe disease being admitted more frequently. Healthcare planning to address potential further increases in admissions and consequent antibiotic prescribing should be a priority.
Assuntos
Infecções Comunitárias Adquiridas/epidemiologia , Hospitalização/estatística & dados numéricos , Pneumonia/epidemiologia , Adulto , Idoso , Infecções Comunitárias Adquiridas/microbiologia , Inglaterra/epidemiologia , Feminino , Humanos , Incidência , Masculino , Pessoa de Meia-Idade , Pneumonia/microbiologiaRESUMO
This study's purpose was to identify distinct publishing trajectories among 442 participants in three prominent mentored health services research career development programs (Veterans Affairs, National Institutes of Health, and Agency for Healthcare Research & Quality) in the 10 years after award receipt and to examine awardee characteristics associated with different trajectories. Curricula vitae (CVs) of researchers receiving awards between 1991 and 2010 were coded for publications, grants, and awardee characteristics. We found that awardees published at constant or increasing rates despite flat or decreasing rates of first-author publications. Senior-author publications rose concurrently with rates of overall publications. Higher overall publication trajectories were associated with receiving more grants, more citations as measured by the h-index, and more authors per article. Lower trajectory groups were older and had a greater proportion of female awardees. Career development awards supported researchers who generally published successfully, but trajectories varied across individual researchers. Researchers' collaborative efforts produced an increasing number of articles, whereas first author articles were written at a more consistent rate. Career development awards in health services research supported the careers of researchers who published at a high rate; future research should further examine reasons for variation in publishing among early career researchers.
Assuntos
Distinções e Prêmios , Pesquisa sobre Serviços de Saúde/estatística & dados numéricos , Publicações Periódicas como Assunto/estatística & dados numéricos , Pesquisadores/estatística & dados numéricos , Distribuição por Idade , Comportamento Cooperativo , Humanos , Grupos Minoritários , National Institutes of Health (U.S.)/estatística & dados numéricos , Apoio à Pesquisa como Assunto , Distribuição por Sexo , Estados Unidos , United States Agency for Healthcare Research and Quality/estatística & dados numéricos , United States Department of Veterans Affairs/estatística & dados numéricosRESUMO
In 1978 the Canadian Chiropractic Association recognized the need to establish an organization that would prepare chiropractors to treat athletic injuries and promote these services to sports organizations. Dr. Adrian Grice approached three chiropractors to establish such an organization. The Canadian Chiropractic Sports Academy (CCSA) was established in 1978. This was the start of the chiropractic sports movement which has seen chiropractors playing prominent roles as team doctors to professional and amateur teams and athletes and in the delivery of care at major national and international competitions. This paper will show the work done by the original founders of the CCSA which has helped to pave the way to the present level of acceptance of chiropractic sports injury management and performance enhancement and as the progenitor of the Royal College of Chiropractic Sports Sciences Canada.
En 1978, l'Association chiropratique canadienne a reconnu la nécessité de créer une organisation qui préparerait les chiropraticiens à traiter les blessures sportives et proposerait ces services à des organisations sportives. Le Dr Adrian Grice a approché trois chiropraticiens pour établir une telle organisation. Le Canadian Chiropractic Sports Academy (CCSA) a été créé en 1978. Ce fut le début du mouvement sportif en chiropratique qui a vu les rôles importants joués par les chiropraticiens en tant que médecins d'équipe auprès d'équipes et d'athlètes professionnels et amateurs, et dans la prestation de soins pendant les principaux événements sportifs nationaux et internationaux. Cet article présente le travail effectué par les fondateurs initiaux du CCSA qui a contribué à ouvrir la voie au niveau actuel d'acceptation de la gestion des blessures sportives en chiropratique et l'amélioration des performances et, comme le prédécesseur du Collège royal des sciences du sport chiropratique (Canada).
RESUMO
PURPOSE: To evaluate the academic advancement and productivity of Department of Veterans Affairs Health Services Research and Development (HSR&D) Career Development Award (CDA) program recipients, National Institutes of Health (NIH) K awardees in health services research (HSR), and Agency for Healthcare Research and Quality (AHRQ) K awardees. METHOD: In all, 219 HSR&D CDA recipients from fiscal year (FY) 1991 through FY2010; 154 NIH K01, K08, and K23 awardees FY1991-FY2010; and 69 AHRQ K01 and K08 awardees FY2000-FY2010 were included. Most data were obtained from curricula vitae. Academic advancement, publications, grants, recognition, and mentoring were compared after adjusting for years since award, and personal characteristics, training, and productivity prior to the award. RESULTS: No significant differences emerged in covariate-adjusted tenure-track academic rank, number of grants as primary investigator (PI), major journal articles as first/sole author, Hirsch h-index scores, likelihood of a journal editorship position or membership in a major granting review panel, or mentoring postgraduate researchers between the HSR&D CDA and NIH K awardees from FY1991-FY2010, or among the three groups of awardees from FY2000 or later. Among those who reported grant funding levels, HSR&D CDAs from FY1991-2010 had been PI on more grants of $100,000 than NIH K awardees. HSR&D CDAs had a higher mean number of major journal articles than NIH K awardees from FY1991-2010. CONCLUSIONS: Findings show that all three HSR career development programs are successfully selecting and mentoring awardees, ensuring additional HSR capacity to improve the quality and delivery of high-value care.
Assuntos
Logro , Eficiência , Pesquisa sobre Serviços de Saúde , Pesquisadores , Adulto , Mobilidade Ocupacional , Feminino , Organização do Financiamento , Humanos , Masculino , National Institutes of Health (U.S.)/economia , Editoração , Relatório de Pesquisa , Apoio à Pesquisa como Assunto , Estudos Retrospectivos , Estados Unidos , United States Agency for Healthcare Research and Quality/economia , United States Department of Veterans Affairs/economiaRESUMO
Historically, mentorship has been conceived of as a dyadic relationship between a senior mentor and an early-career investigator. Models involving multiple mentors have gained favor in recent years, but empirical research on multiple-mentor models has been lacking. The current work aims to fill this gap by describing a long-standing health services research mentoring program at the U.S. Department of Veterans Affairs which has adopted a network-based approach to mentoring. As part of a broader project, we surveyed VA HSR&D Career Development Awardees who received an award between 2000 and 2012. In total, 133 awardees participated (84%). Awardees reported on the structure of mentoring relationships with their two most influential mentors. Awardees were mentored by teams consisting of one to five mentors (M = 2.7 mentors). Most often, one mentor served as primary mentor while one or more mentors played a supporting role. In most cases, an awardee's primary mentor was co-located with the awardee, with fewer secondary mentors co-located. More recently funded CDAs had more mentors and were less likely to be co-located with secondary mentors. The VA HSR&D CDA program incorporates current thinking about Developmental Network models of mentorship into a comprehensive program providing a rich mentorship experience for its awardees.