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Planets with radii between that of the Earth and Neptune (hereafter referred to as 'sub-Neptunes') are found in close-in orbits around more than half of all Sun-like stars1,2. However, their composition, formation and evolution remain poorly understood3. The study of multiplanetary systems offers an opportunity to investigate the outcomes of planet formation and evolution while controlling for initial conditions and environment. Those in resonance (with their orbital periods related by a ratio of small integers) are particularly valuable because they imply a system architecture practically unchanged since its birth. Here we present the observations of six transiting planets around the bright nearby star HD 110067. We find that the planets follow a chain of resonant orbits. A dynamical study of the innermost planet triplet allowed the prediction and later confirmation of the orbits of the rest of the planets in the system. The six planets are found to be sub-Neptunes with radii ranging from 1.94Râ to 2.85Râ. Three of the planets have measured masses, yielding low bulk densities that suggest the presence of large hydrogen-dominated atmospheres.
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The integral steric asymmetry for the inelastic scattering of NO(X) by a variety of collision partners was recorded using a crossed molecular beam apparatus. The initial state of the NO(X, v = 0, j = 1/2, Ω=1/2, ϵ=-1,f) molecule was selected using a hexapole electric field, before the NO bond axis was oriented in a static electric field, allowing probing of the scattering of the collision partner at either the N- or O-end of the molecule. Scattered NO molecules were state selectively probed using (1 + 1') resonantly enhanced multiphoton ionisation, coupled with velocity-map ion imaging. Experimental integral steric asymmetries are presented for NO(X) + Ar, for both spin-orbit manifolds, and Kr, for the spin-orbit conserving manifold. The integral steric asymmetry for spin-orbit conserving and changing transitions of the NO(X) + O2 system is also presented. Close-coupled quantum mechanical scattering calculations employing well-tested ab initio potential energy surfaces were able to reproduce the steric asymmetry observed for the NO-rare gas systems. Quantum mechanical scattering and quasi-classical trajectory calculations were further used to help interpret the integral steric asymmetry for NO + O2. Whilst the main features of the integral steric asymmetry of NO with the rare gases are also observed for the O2 collision partner, some subtle differences provide insight into the form of the underlying potentials for the more complex system.
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We describe the synthesis of metal chelating polymers based on polyaspartamide and polyglutamide backbones as carriers for (111)In in radioimmunoconjugates. These polymers [PAsp(DTPA), PGlu(DTPA)] have a biotin end group and diethylenetriaminepentaacetic acid (DTPA) chelators attached to the primary amines of the diethylenetriamine (DET) pendant groups of biotin-poly{N'-[N-(2-aminoethyl)-2-aminoethyl]aspartamide} [PAsp(DET)] and of biotin-poly{N'-[N-(2-aminoethyl)-2-aminoethyl]glutamide} [PGlu(DET)]. Like Asn-containing proteins and polypeptides, polyaspartamides undergo uncatalyzed degradation under model physiological conditions (10 mM phosphate buffer, pH 7.4, 150 mM NaCl). We studied the uncatalyzed degradation of the polyaspartamide polymers by size exclusion chromatography and found that the degradation rate was sensitive to the nature of the pendant groups. The metal-free polymer underwent somewhat slower degradation than the corresponding polymers in which the DTPA groups were saturated with Eu(3+) or In(3+), but even after 14 days, substantial fractions of the polymers survived. We conclude that these polymers undergo negligible degradation on the time scale (24-48 h) of radioimmunotherapy treatment of tumors with (111)In. From a mechanistic perspective, we note that these degradation rates are on the order of the deamidation rates reported [J. Peptide Res. 2004, 63, 426] for Asn-containing pentapeptides, with half-times on the order of 10 days, but much slower than the rapid decay (hours) reported recently [Biomaterials 2010, 31, 3707] for poly{N'-[N-(2-aminoethyl)-2-aminoethyl]aspartamide} itself. This variation in degradation rate can be explained in terms of the influence of positive charges on the pendant group enhancing the acidity of the side-chain amide nitrogen of the aspartamide repeat unit. The DET pendant group is positively charged at pH 7, but in indium-loaded PAsp(DTPA) this charge is offset by the net negative charge of the DTPA-In complex.
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Complexos de Coordenação/química , Peptídeos/química , Físico-Química , Complexos de Coordenação/síntese química , Hidrólise , Estrutura Molecular , Peptídeos/síntese químicaRESUMO
Twenty-eight Holstein Friesian dairy heifers were assigned to 1 of 2 treatments after calving. These experimental heifers were introduced to an established group of resident cows either between 0600 and 0800h (i.e., after morning milking, a.m.) or between 1600 and 1800 h (i.e., after evening milking, p.m.). The size of the resident group remained constant at 18 animals (12 multiparous cows and 6 primiparous cows). There were 5 replicate or resident groups in total, and 2 to 3 nonexperimental primiparous cows in each group were replaced by a.m. and by p.m. heifers as they calved. Fresh total mixed ration was provided daily between 1000 and 1030 h, and concentrate feed was offered in the milking parlor. The behavior of the experimental heifers was assessed over a 2-h period immediately after mixing into the resident group, and also after feed provision during the first month in the group. In addition, time spent lying was assessed each week for 1 mo using data loggers attached over 24-h periods. The lying behavior and location of the entire group was also assessed by direct observations during the 2-h period before evening milking on 2 consecutive days each week for 1 mo. The time spent feeding by experimental heifers was recorded automatically using computerized feeding gates. Milk production, milk cortisol concentrations, and changes in body condition and body weight were also assessed over the first month after calving. Heifers in the a.m. treatment spent longer in receipt of aggressive behaviors such as threats, butts, and chases immediately after mixing compared with those in the p.m. treatment. During the feeding periods, heifers in the a.m. treatment were observed feeding for longer, showed less pen exploration, and also received more butts. No significant treatment effects were shown on overall feed intake levels, milk yield, milk cortisol concentrations, body weight, or body condition score loss. However, feed intakes were higher in the a.m. treatment during the second week after mixing, and automated recordings showed that a.m. animals spent longer average periods of time feeding. No significant treatment differences were shown in overall time spent lying, with heifers in both treatments lying for less than 4h during the first 24h in the group. Observations of the entire group showed that p.m. heifers spent less time lying than resident animals or a.m. heifers. In conclusion, the reduction in received aggression and the lack of adverse effects on performance (milk production and weight and condition loss) suggest that heifers should be introduced to the main dairy herd after evening rather than morning milking. Further research to determine the relative importance of time of day and time since feeding on behavior immediately after mixing would be beneficial.
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Indústria de Laticínios/métodos , Animais , Comportamento Animal , Peso Corporal , Bovinos , Comportamento Alimentar , Feminino , Hidrocortisona/análise , Lactação , Leite/química , Paridade , Fatores de TempoRESUMO
INTRODUCTION: Sedation of children for short painful procedures is increasingly performed in emergency departments as an alternative to hospital admission and theatre. In this study, the savings of this are sought to be quantified. METHODS: A matched-cohort economic evaluation was conducted. Detailed case note reviews were performed on children who were sedated in the emergency department and children who were admitted to theatre. The costs of these were compared. RESULTS: 17 children underwent sedation in our emergency department and were compared with 20 children admitted to theatre. Each emergency department sedation saved £614 (95% CI £441 to £787), and this result was statistically significant (p<0.0001). CONCLUSION: Emergency department sedation offers considerable savings, compared with theatre-based management for children who require short painful procedures.
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Anestésicos Dissociativos/administração & dosagem , Sedação Consciente/economia , Serviço Hospitalar de Emergência/economia , Custos Hospitalares/estatística & dados numéricos , Ketamina/administração & dosagem , Ferimentos e Lesões/terapia , Criança , Pré-Escolar , Redução de Custos , Inglaterra , Feminino , Humanos , Lactente , Masculino , Admissão do Paciente/economia , Ferimentos e Lesões/economiaRESUMO
Humpback whales (Megaptera novaeangliae) are a cosmopolitan species and perform long annual migrations between low-latitude breeding areas and high-latitude feeding areas. Their breeding populations appear to be spatially and genetically segregated due to long-term, maternally inherited fidelity to natal breeding areas. In the Southern Hemisphere, some humpback whale breeding populations mix in Southern Ocean waters in summer, but very little movement between Pacific and Atlantic waters has been identified to date, suggesting these waters constituted an oceanic boundary between genetically distinct populations. Here, we present new evidence of summer co-occurrence in the West Antarctic Peninsula feeding area of two recovering humpback whale breeding populations from the Atlantic (Brazil) and Pacific (Central and South America). As humpback whale populations recover, observations like this point to the need to revise our perceptions of boundaries between stocks, particularly on high latitude feeding grounds. We suggest that this "Southern Ocean Exchange" may become more frequent as populations recover from commercial whaling and climate change modifies environmental dynamics and humpback whale prey availability.
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Jubarte/fisiologia , Reprodução , Migração Animal , Animais , Mudança Climática , Comportamento Alimentar , Oceanos e MaresRESUMO
BACKGROUND: The delivery of out-of-hours primary medical care in the United Kingdom has changed substantially since 2004, and there has been little examination of the effect that this has on secondary care. AIM: The authors aimed to quantify the change in patient type presenting to our emergency department. METHODS: In this study, routinely collected coding data before, during and after the changes were analysed. Each September and October between 1999 and 2006 were included. RESULTS: There was a steady increase in all attendances at our emergency department. The number and proportions of patients with non-traumatic conditions rose steadily throughout the study period. The number of patients presenting with traumatic conditions stayed the same. The number of patients presenting with non-traumatic conditions out-of-hours rose after the changes were implemented. INTERPRETATION: The changes to the provision of out-of-hours primary care have been associated with an increase in patients with non-traumatic attendances presenting to our emergency department. This effect is most marked outside of office hours.
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Plantão Médico/organização & administração , Serviço Hospitalar de Emergência/estatística & dados numéricos , Atenção Primária à Saúde/estatística & dados numéricos , Serviço Hospitalar de Emergência/tendências , Necessidades e Demandas de Serviços de Saúde/estatística & dados numéricos , Hospitais Gerais , Humanos , Estudos Longitudinais , Atenção Primária à Saúde/organização & administração , Reino UnidoRESUMO
The tuning curve has been measured, in vivo, at a point approximately 1.5 millimeters from the stapes in the first turn of the guinea pig cochlea. Curves for constant stapes movement and constant sound pressure were obtained over the range 350 hertz to 30 kilohertz, with an amplitude peak at about 18 kilohertz.
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Orelha Interna/fisiologia , Som , Vibração , Animais , Fenômenos Biofísicos , Biofísica , Ossículos da Orelha/fisiologia , CobaiasRESUMO
BACKGROUND: The Ottawa knee rule (OKR), a clinical decision aid is used to reduce unnecessary radiography. It is not clear whether this rule can be applied to children. OBJECTIVE: To establish whether the OKR had adequate sensitivity and acceptable specificity in children to advocate widespread use. METHODS: A systematic review and meta-analysis was conducted of observational studies that examined the diagnostic characteristics of the OKR in children. DATA SOURCES: Relevant English language articles were identified from Medline (1950 to date), EMBASE (1974 to date), CINAHL (1982 to date), the Cochrane Library, Google Scholar and a hand search of bibliographies. STUDY SELECTION: Observational studies that included children and have used the OKR for ruling out fractures in children either radiologically or in combination with follow-up. RESULTS: Four relevant studies were identified. Three studies were suitable for inclusion in the meta-analysis, representing 1130 children. The pooled negative likelihood ratio was 0.07 (95% CI 0.02 to 0.29), the pooled positive likelihood ratio was 1.94 (95% CI 1.60 to 2.36), the pooled sensitivity was 99% (CI 94.4 to 99.8) and the pooled specificity was 46% (CI 43.0 to 49.1). The reduction in radiography was between 30% and 40%. CONCLUSION: The OKR has high sensitivity and adequate specificity for children over the age of 5 years. There are not enough good data to advocate application of the OKR in children less than 5 years.
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Técnicas de Apoio para a Decisão , Fraturas Ósseas/diagnóstico , Traumatismos do Joelho/diagnóstico , Adolescente , Criança , Pré-Escolar , Fraturas Ósseas/diagnóstico por imagem , Humanos , Lactente , Traumatismos do Joelho/diagnóstico por imagem , Seleção de Pacientes , Radiografia , Sensibilidade e Especificidade , Procedimentos Desnecessários/estatística & dados numéricosRESUMO
BACKGROUND: There has been an increasing demand for computed tomography (CT) scans of the head following trauma over the past 10 years. This has placed radiology services under pressure. AIMS: This study aimed to see whether middle grade and consultant doctors with no particular training in radiology working in the emergency department could interpret CT scans performed for trauma with adequate sensitivity and specificity to allow safe discharge. The secondary aim was to describe which abnormalities, if any, were missed. METHODS: Study participants were middle grade and consultant emergency physicians. A comparison was made of the ability to identify any abnormality on CT and a clinically important brain injury on CT, compared with a gold standard of a neuroradiology report. RESULTS: 243 consecutive CT scans performed for trauma were reviewed by 17 doctors, including five consultants. The overall sensitivity and specificity for detecting clinically important brain injuries was 87.8 (95% CI 73.8 to 95.9) and 80.2 (95% CI 75.2 to 85.3), respectively. All the missed abnormalities were around the base of the brain. The most commonly overdiagnosed abnormality was diffuse cerebral oedema. CONCLUSIONS: Emergency physicians should not interpret CT scans for trauma without extra training.
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Competência Clínica/normas , Traumatismos Craniocerebrais/diagnóstico por imagem , Medicina de Emergência/normas , Corpo Clínico Hospitalar/normas , Tomografia Computadorizada por Raios X/normas , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Criança , Pré-Escolar , Consultores , Estudos Transversais , Serviço Hospitalar de Emergência/normas , Feminino , Humanos , Lactente , Masculino , Pessoa de Meia-Idade , Adulto JovemRESUMO
BACKGROUND: This study investigated differences in weight loss outcomes in obese women with Type 2 diabetes (T2D) compared to those without T2D attending a 6-month dietetic led 'Lifestyle' intervention. In those who had failed to reach weight loss goals using the 'Lifestyle' approach, the study further examined the effect on weight loss with the addition of sibutramine (Reductil, Abbott Laboratories, USA) over a 6-month period. METHODS: The study comprised a case-control analysis of data from 38 obese female patients (18 with T2D) from the 'Lifestyle' and 'Pharmacotherapy' clinics attending a tertiary hospital in the UK. RESULTS: In the 'Lifestyle' treatment groups, those with T2D lost significantly less body weight than those without T2D [5.26 kg (4.54%) versus 9.89 kg (9.55%), respectively]. For subjects who had failed to lose weight via the 'Lifestyle' intervention, the addition of sibutramine resulted in a similar weight loss compared to their pair-matched 'Lifestyle' only 'successful' counterparts (9.66% versus 9.55%). CONCLUSIONS: Not all obese women, and those with T2D in particular, will derive benefit from 'Lifestyle' advice and those who are resistant to this treatment approach may be assisted by pharmacotherapy. Dietitians can play a role in identifying those individuals who may benefit from the use of pharmacotherapy.
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Depressores do Apetite/uso terapêutico , Ciclobutanos/uso terapêutico , Diabetes Mellitus Tipo 2/terapia , Estilo de Vida , Obesidade/terapia , Redução de Peso , Adulto , Índice de Massa Corporal , Terapia Combinada , Diabetes Mellitus Tipo 2/dietoterapia , Diabetes Mellitus Tipo 2/tratamento farmacológico , Dieta Redutora , Feminino , Humanos , Pessoa de Meia-Idade , Obesidade/dietoterapia , Obesidade/tratamento farmacológico , Estudos Retrospectivos , Resultado do Tratamento , Redução de Peso/efeitos dos fármacos , Redução de Peso/fisiologiaRESUMO
BACKGROUND: There is uncertainty about the most efficient model of emergency care. An attempt has been made to improve the process of emergency care in one hospital by developing an integrated model. METHODS: The medical admissions unit was relocated into the existing emergency department and came under the 4-hour target. Medical case records were redesigned to provide a common assessment document for all patients presenting as an emergency. Medical, surgical and paediatric short-stay wards were opened next to the emergency department. A clinical decision unit replaced the more traditional observation unit. The process of patient assessment was streamlined so that a patient requiring admission was fully clerked by the first attending doctor to a level suitable for registrar or consultant review. Patients were allocated directly to specialty on arrival. The effectiveness of this approach was measured with routine data over the same 3-month periods in 2005 and 2006. RESULTS: There was a 16.3% decrease in emergency medical admissions and a 3.9% decrease in emergency surgical admissions. The median length of stay for emergency medical patients was reduced from 7 to 5 days. The efficiency of the elective surgical services was also improved. Performance against the 4-hour target declined but was still acceptable. The number of bed days for admitted surgical and medical cases rose slightly. There was an increase in the number of medical outliers on surgical wards, a reduction in the number of incident forms and formal complaints and a reduction in income for the hospital. CONCLUSIONS: Integrated emergency care has the ability to use spare capacity within emergency care. It offers significant advantages beyond the emergency department. However, improved efficiency in processing emergency patients placed the hospital at a financial disadvantage.
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Prestação Integrada de Cuidados de Saúde/organização & administração , Eficiência Organizacional , Serviço Hospitalar de Emergência/organização & administração , Modelos Organizacionais , Humanos , Estudos de Casos Organizacionais , Avaliação de Resultados em Cuidados de Saúde , Reino UnidoRESUMO
This consensus statement update reflects our current published knowledge and opinion about clinical signs, pathogenesis, epidemiology, treatment, complications, and control of strangles. This updated statement emphasizes varying presentations in the context of existing underlying immunity and carrier states of strangles in the transmission of disease. The statement redefines the "gold standard" for detection of possible infection and reviews the new technologies available in polymerase chain reaction diagnosis and serology and their use in outbreak control and prevention. We reiterate the importance of judicious use of antibiotics in horses with strangles. This updated consensus statement reviews current vaccine technology and the importance of linking vaccination with currently advocated disease control and prevention programs to facilitate the eradication of endemic infections while safely maintaining herd immunity. Differentiation between immune responses to primary and repeated exposure of subclinically infected animals and responses induced by vaccination is also addressed.
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Doenças dos Cavalos/diagnóstico , Linfadenite/diagnóstico , Infecções Estreptocócicas/veterinária , Animais , Consenso , Surtos de Doenças/prevenção & controle , Surtos de Doenças/veterinária , Doenças dos Cavalos/imunologia , Doenças dos Cavalos/prevenção & controle , Doenças dos Cavalos/terapia , Cavalos , Linfadenite/imunologia , Linfadenite/prevenção & controle , Linfadenite/terapia , Infecções Estreptocócicas/diagnóstico , Infecções Estreptocócicas/imunologia , Infecções Estreptocócicas/prevenção & controle , Streptococcus equi/imunologia , Vacinação/veterináriaRESUMO
Accurate characterization of laser pulses used in experiments is a crucial step to the analysis of their results. In this paper, a novel single-shot frequency-resolved optical gating (FROG) device is described, one that incorporates a dispersive element which allows it to fully characterize pulses up to 25 ps in duration with a 65 fs per pixel temporal resolution. A newly developed phase retrieval routine based on memetic algorithms is implemented and shown to circumvent the stagnation problem that often occurs with traditional FROG analysis programs when they encounter a local minimum.
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Until recently, the concept of treating the injured or failing heart by generating new functional myocardium was considered physiologically impossible. Major scientific strides in the past few years have challenged the concept that the heart is a post-mitotic organ, leading to the hypothesis that cardiac regeneration could be therapeutically achieved. Bone marrow-derived adult stem cells were among the first cell populations that were used to test this hypothesis. Animal studies and early clinical experience support the concept that therapeutically delivered mesenchymal stem cells (MSCs) safely improve heart function after an acute myocardial infarction (MI). MSCs produce a variety of cardio-protective signalling molecules, and have the ability to differentiate into both myocyte and vascular lineages. Additionally, MSCs are attractive as a cellular vehicle for gene delivery, cell transplantation or for tissue engineering because they offer several practical advantages. They can be obtained in relatively large numbers through standard clinical procedures, and they are easily expanded in culture. The multi-lineage potential of MSC, in combination with their immunoprivileged status, make MSCs a promising source for cell therapy in cardiac diseases. Here we provide an overview of biological characteristics of MSCs, experimental animal studies and early clinical trials with MSCs. In addition, we discuss the routes of cell delivery, cell tracking experiments and current knowledge of the mechanistic underpinnings of their action.
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Terapia Genética , Transplante de Células-Tronco Mesenquimais , Infarto do Miocárdio/terapia , Animais , Ensaios Clínicos como Assunto , Humanos , Células-Tronco Mesenquimais/imunologia , Células-Tronco Mesenquimais/fisiologia , Engenharia TecidualRESUMO
OBJECTIVE: To establish whether UK emergency physicians could reliably perform focused ultrasound of the abdominal aorta in patients with suspected abdominal aortic aneurysm (AAA). METHODS: A prospective cohort study was conducted in the emergency department of a tertiary level UK teaching hospital. All patients who underwent an abdominal aortic ultrasound by an emergency physician during a 12 month period from January to December 2005 were included. The principle outcomes were presence of an AAA (external wall diameter >3 cm) or death from ruptured AAA. Outcome data were obtained from paper and electronic patient records and primary care telephone follow up. RESULTS: 120 focused ultrasound scans looking for AAA were performed by 19 different UK emergency physicians of various grades. Of the 120 scans, 26 (22%) were positive for an AAA, of which 17 cases represented a new diagnosis. Ruptured aneurysms represented 46% (12/26) of all positive scans, of which four patients underwent emergency repair. In the remaining 14 patients the AAA was an incidental finding that was not the reason for their presentation to the emergency department. Emergency ultrasound had a sensitivity of 96.3% (95% confidence interval (CI) 81.0% to 99.9%); a specificity of 100% (95% CI 91.8% to 100%); a negative predictive value of 98.6% (95% CI 88.0% to 99.9%); and positive predictive value of 100% (95% CI 86.8% to 100%) for the detection of AAA. CONCLUSION: Emergency ultrasound scanning by UK emergency physicians has high sensitivity and specificity for identifying AAA, consistent with international experience.
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Aneurisma da Aorta Abdominal/diagnóstico por imagem , Medicina de Emergência/estatística & dados numéricos , Adulto , Idoso , Idoso de 80 Anos ou mais , Competência Clínica/estatística & dados numéricos , Estudos de Coortes , Medicina de Emergência/métodos , Seguimentos , Humanos , Pessoa de Meia-Idade , Estudos Prospectivos , Sensibilidade e Especificidade , Ultrassonografia , Reino UnidoRESUMO
BACKGROUND: Methicillin-resistant Staphylococcus aureus (MRSA) is recognized as a cause of nosocomial infections in both human and veterinary medicine. Studies that examine the nasopharynx and guttural pouches of the horse as carriage sites for MRSA have not been reported. HYPOTHESIS/OBJECTIVE: MRSA colonizes the nasopharynx and guttural pouch of horses. To determine the prevalence of MRSA in equine nasopharyngeal wash (NPW) and guttural pouch lavage (GPL) samples in a field population of horses. SAMPLES: One hundred seventy-eight samples (123 NPW and 55 GPL) from 108 horses. METHODS: Prospective study. Samples were collected from a convenience population of clinically ill horses with suspected Streptococcus equi subsp. equi (S. equi) infection, horses convalescing from a known S. equi infection, and asymptomatic horses undergoing S. equi screening. Samples were submitted for S. aureus aerobic bacterial culture with mannitol salt broth and two selective agars (cefoxitin CHROMagar as the PBP2a inducer and mannitol salt agar with oxacillin). Biochemical identification of Staphylococcus species and pulsed-field gel electrophoresis (PFGE), to determine clonal relationships between isolates, were performed. RESULTS: Methicillin-resistant Staphylococcus (MRS) was isolated from the nasopharynx of 7/108 (4%) horses. Three horses had MRSA (2.7%), and 4 had MR-Staphylococcus pseudintermedius (MRSP). MRSA was isolated from horses on the same farm. PFGE revealed the 3 MRSA as USA 500 strains. CONCLUSIONS AND CLINICAL IMPORTANCE: Sampling the nasopharynx and guttural pouch of community-based horses revealed a similarly low prevalence rate of MRSA as other studies sampling the nares of community-based horses. More study is required to determine the need for sampling multiple anatomic sites when screening horses for MRSA.
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Tuba Auditiva/microbiologia , Doenças dos Cavalos/epidemiologia , Staphylococcus aureus Resistente à Meticilina , Nasofaringe/microbiologia , Infecções Estafilocócicas/veterinária , Animais , Portador Sadio/microbiologia , Portador Sadio/veterinária , Eletroforese em Gel de Campo Pulsado/veterinária , Feminino , Doenças dos Cavalos/tratamento farmacológico , Doenças dos Cavalos/microbiologia , Cavalos/microbiologia , Masculino , Infecções Estafilocócicas/tratamento farmacológico , Infecções Estafilocócicas/epidemiologia , Infecções Estafilocócicas/microbiologiaRESUMO
Electrical impedance tomography (EIT) or electrical resistivity tomography (ERT) current and measure voltages at the boundary of a domain through electrodes. SIGNIFICANCE: The movement or incorrect placement of electrodes may lead to modelling errors that result in significant reconstructed image artifacts. These errors may be accounted for by allowing for electrode position estimates in the model. Movement may be reconstructed through a first-order approximation, the electrode position Jacobian. A reconstruction that incorporates electrode position estimates and conductivity can significantly reduce image artifacts. Conversely, if electrode position is ignored it can be difficult to distinguish true conductivity changes from reconstruction artifacts which may increase the risk of a flawed interpretation. OBJECTIVE: In this work, we aim to determine the fastest, most accurate approach for estimating the electrode position Jacobian. APPROACH: Four methods of calculating the electrode position Jacobian were evaluated on a homogeneous halfspace. MAIN RESULTS: Results show that Fréchet derivative and rank-one update methods are competitive in computational efficiency but achieve different solutions for certain values of contact impedance and mesh density.
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Processamento de Imagem Assistida por Computador/métodos , Tomografia/instrumentação , Artefatos , Impedância Elétrica , Eletrodos , MovimentoRESUMO
OBJECTIVES: To assess whether allogeneic blood transfusion in the perioperative period is associated with changes in mortality or complication rates in patients undergoing surgical treatment for hip fracture (proximal femoral fracture). DESIGN: Retrospective case-control series, all patients followed up for 1 year or until death. SETTING: District General Hospital in Peterborough, UK. PATIENTS PARTICIPANTS: Three thousand six hundred twenty-five consecutive patients admitted and operated for hip fracture (proximal femoral fracture) during July 1989 to January 2002 (151 months); 1068 (29.9%) received a perioperative allogeneic blood transfusion. MAIN OUTCOME MEASURES: Thirty- 120-, and 365-day mortality, deep and superficial wound infection rates. RESULTS: Overall mortality for all patients at 1 year post fracture was 28.2% (1007 patients). Transfusion was associated with a statistically significant increase in mortality from 120 days onward after hip fracture. However, when this was adjusted with a statistical regression model for baseline characteristics and confounding variables, this difference became statistically insignificant (P = 0.17). Infection rates in the transfusion group were 2.0% for superficial infection and 0.9% for deep infection compared with 1.9% and 0.6%, respectively, in the nontransfusion group. These figures were not statistically significantly different. Other complications of deep venous thrombosis, chest infection, and congestive cardiac failure showed no statistically significant increase in those patients who received transfusion. CONCLUSIONS: Our data suggest that transfusion is not associated with a change in mortality or infection rates in the hip-fracture patient.