Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 371
Filtrar
1.
Philos Stud ; 180(9): 2871-2893, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37662848

RESUMO

Are interpersonal comparisons of desire possible? Can we give an account of how facts about desires are grounded that underpins such comparisons? This paper supposes the answer to the first question is yes, and provides an account of the nature of desire that explains how this is so. The account is a modification of the interpretationist metaphysics of representation that the author has recently been developing. The modification is to allow phenomenological affective valence into the "base facts" on which correct interpretation is grounded. To use this extra resource within that theory to vindicate interpersonal comparisons, we will need to appeal rational connections between level of valence and level of desire, which this paper sets out and examines.

2.
Erkenntnis ; 88(3): 1059-1080, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-36950313

RESUMO

Information can be public among a group. Whether or not information is public matters, for example, for accounts of interdependent rational choice, of communication, and of joint intention. A standard analysis of public information identifies it with (some variant of) common belief. The latter notion is stipulatively defined as an infinite conjunction: for p to be commonly believed is for it to believed by all members of a group, for all members to believe that all members believe it, and so forth. This analysis is often presupposed without much argument in philosophy. Theoretical entrenchment or intuitions about cases might give some traction on the question, but give little insight about why the identification holds, if it does. The strategy of this paper is to characterize a practical-normative role for information being public, and show that the only things that play that role are (variants of) common belief as stipulatively characterized. In more detail: a functional role for "taking a proposition for granted" in non-isolated decision making is characterized. I then present some minimal conditions under which such an attitude is correctly held. The key assumption links this attitude to beliefs about what is public. From minimal a priori principles, we can argue that a proposition being public among a group entails common commitment to believe among that group. Later sections explore partial converses to this result, the factivity of publicity and publicity from the perspective of outsiders to the group, and objections to the aprioricity of the result deriving from a posteriori existential presuppositions. Supplementary Information: The online version contains supplementary material available at 10.1007/s10670-021-00393-x.

3.
Osteoarthritis Cartilage ; 31(1): 96-105, 2023 01.
Artigo em Inglês | MEDLINE | ID: mdl-36252943

RESUMO

OBJECTIVE: Evaluate patellofemoral cartilage health, as assessed by quantitative magnetic resonance imaging (qMRI) T2 relaxation times, 24-months after ACL reconstruction (ACLR) and determine if they were associated with patellofemoral contact forces and knee mechanics during gait 3 months after surgery. DESIGN: Thirty individuals completed motion analysis during overground walking at a self-selected speed 3 months after ACLR. An EMG-driven neuromusculoskeletal model was used to determine muscle forces, which were then used in a previously described model to estimate patellofemoral contact forces. Biomechanical variables of interest included peak patellofemoral contact force, peak knee flexion angle and moment, and walking speed. These same participants underwent a sagittal bilateral T2 mapping qMRI scan 24-months after surgery. T2 relaxation times were estimated for both patellar and trochlear cartilage. Paired t-tests were used to compare T2 relaxation times between limbs while Pearson correlations and linear regressions were utilized to assess the association between the biomechanical variables of interest and T2 relaxation times. RESULTS: Prolonged involved limb trochlear T2 relaxation times (vs uninvolved) were present 24-months after surgery, indicating worse cartilage health. No differences were detected in patellar cartilage. Significant negative associations were present within the involved limb for all the biomechanical variables of interest 3 months after ACLR and trochlear T2 relaxation times at 24-months. No associations were found in patellar cartilage or within the uninvolved limb. CONCLUSIONS: Altered involved limb trochlear cartilage health is present 24-months after ACLR and may be related to patellofemoral loading and other walking gait mechanics 3 months after surgery.


Assuntos
Lesões do Ligamento Cruzado Anterior , Reconstrução do Ligamento Cruzado Anterior , Cartilagem Articular , Osteoartrite do Joelho , Humanos , Reconstrução do Ligamento Cruzado Anterior/métodos , Cartilagem Articular/patologia , Osteoartrite do Joelho/patologia , Articulação do Joelho/diagnóstico por imagem , Articulação do Joelho/cirurgia , Marcha/fisiologia , Lesões do Ligamento Cruzado Anterior/cirurgia , Imageamento por Ressonância Magnética/métodos , Fenômenos Biomecânicos
4.
Geophys Res Lett ; 49(21): e2022GL099563, 2022 Nov 16.
Artigo em Inglês | MEDLINE | ID: mdl-36583182

RESUMO

Sinking particles are important in delivering carbon to the deep ocean where it may be stored out of contact with the atmosphere. Whilst particle sinking velocities are known to be influenced by a multitude of factors, size-based parameterizations remain common in biogeochemical models and in the methods used to determine particulate fluxes from autonomous platforms. Here we carried out an extensive literature review (62 data sets) into the size-sinking velocity relationship, and find the relationship is much weaker for studies examining particles in situ (median R 2 = 0.09) compared with ex situ studies (median R 2 = 0.35). This discrepancy may be because particles examined in the laboratory have more uniform properties than those studied in situ. Our review highlights the shortcomings of using a simple relationship between size and sinking velocity to calculate sinking particulate fluxes in the ocean; considering additional particle characteristics will enable more accurate calculations of particulate fluxes.

5.
Nature ; 606(7913): 281-286, 2022 06.
Artigo em Inglês | MEDLINE | ID: mdl-35585238

RESUMO

Substantial leaps in the understanding of quantum systems have been driven by exploring geometry, topology, dimensionality and interactions in ultracold atomic ensembles1-6. A system where atoms evolve while confined on an ellipsoidal surface represents a heretofore unexplored geometry and topology. Realizing an ultracold bubble-potentially Bose-Einstein condensed-relates to areas of interest including quantized-vortex flow constrained to a closed surface topology, collective modes and self-interference via bubble expansion7-17. Large ultracold bubbles, created by inflating smaller condensates, directly tie into Hubble-analogue expansion physics18-20. Here we report observations from the NASA Cold Atom Lab21 facility onboard the International Space Station of bubbles of ultracold atoms created using a radiofrequency-dressing protocol. We observe bubble configurations of varying size and initial temperature, and explore bubble thermodynamics, demonstrating substantial cooling associated with inflation. We achieve partial coverings of bubble traps greater than one millimetre in size with ultracold films of inferred few-micrometre thickness, and we observe the dynamics of shell structures projected into free-evolving harmonic confinement. The observations are among the first measurements made with ultracold atoms in space, using perpetual freefall to explore quantum systems that are prohibitively difficult to create on Earth. This work heralds future studies (in orbital microgravity) of the Bose-Einstein condensed bubble, the character of its excitations and the role of topology in its evolution.

6.
Eur J Neurol ; 27(5): 878-886, 2020 05.
Artigo em Inglês | MEDLINE | ID: mdl-32009276

RESUMO

BACKGROUND AND PURPOSE: The purpose was to determine the test-retest reliability, practice effects, convergent validity and sensitivity to multiple sclerosis (MS) disability of neuroperformance subtests from the patient self-administered Multiple Sclerosis Performance Test (MSPT) designed to assess low contrast vision (Contrast Sensitivity Test, CST), upper extremity motor function (Manual Dexterity Test, MDT) and lower extremity motor function (Walking Speed Test, WST) and to introduce the concept of regression-based norms to aid clinical interpretation of performance scores using the MSPT cognition test (Processing Speed Test, PST) as an example. METHODS: Substudy 1 assessed test-retest reliability, practice effects and convergent validity of the CST, MDT and WST in 30 MS patients and 30 healthy controls. Substudy 2 examined sensitivity to MS disability in over 600 MS patients as part of their routine clinic assessment. Substudy 3 compared performance on the PST in research volunteers and clinical samples. RESULTS: The CST, MDT and WST were shown to be reliable, valid and sensitive to MS outcomes. Performance was comparable to technician-administered testing. PST performance was poorer in the clinical sample compared with the research volunteer sample. CONCLUSIONS: The self-administered MSPT neuroperformance modules produce reliable, objective metrics that can be used in clinical practice and support outcomes research. Published studies which require patient voluntary consent may underestimate the rate of cognitive dysfunction observed in a clinical setting.


Assuntos
Esclerose Múltipla , Cognição , Disfunção Cognitiva , Humanos , Esclerose Múltipla/diagnóstico , Avaliação de Resultados em Cuidados de Saúde , Reprodutibilidade dos Testes
7.
Drug Alcohol Depend ; 207: 107799, 2020 02 01.
Artigo em Inglês | MEDLINE | ID: mdl-31865058

RESUMO

INTRODUCTION: Opioid use disorder (OUD) is common among people in jail and is effectively treated with medications for OUD (MOUD). People with OUD may have an incomplete or inaccurate understanding of OUD and MOUD, and of how to access care. We evaluated an OUD treatment decision making (TDM) intervention to determine whether the intervention increased MOUD initiation post-release. METHODS: We conducted an observational retrospective cohort study of the TDM intervention on initiation of MOUD, individuals with records data indicating confirmed or suspected OUD incarcerated in four eligible jails were eligible to receive the intervention. Time-to-event analyses of the TDM intervention were conducted using Cox proportional hazard modeling with MOUD as the outcome. RESULTS: Cox proportional hazard modeling, with the intervention modeled as having a time-varying effect due to violation of the proportionality assumption, indicated that those receiving the TDM intervention (n = 568) were significantly more likely to initiate MOUD during the first month after release from jail (adjusted hazard ratio 6.27, 95 % C.I. 4.20-9.37), but not in subsequent months (AHR 1.33 95 % C.I. 0.94-1.89), adjusting for demographics, prior MOUD, or felony or gross misdemeanor arrest in the prior year compared to those not receiving the intervention (n = 3174). CONCLUSION: The TDM intervention was associated with a significantly higher relative hazard of starting MOUD, specifically during the first month after incarceration. However, a minority of all eligible people received any MOUD. Future research should examine ways to increase initiation on MOUD immediately after (or ideally during) incarceration.


Assuntos
Terapia Comportamental/métodos , Tratamento de Substituição de Opiáceos/estatística & dados numéricos , Transtornos Relacionados ao Uso de Opioides/psicologia , Educação de Pacientes como Assunto/métodos , Prisioneiros/psicologia , Adolescente , Adulto , Buprenorfina/uso terapêutico , Tomada de Decisões , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Naltrexona/uso terapêutico , Tratamento de Substituição de Opiáceos/psicologia , Transtornos Relacionados ao Uso de Opioides/tratamento farmacológico , Aceitação pelo Paciente de Cuidados de Saúde/psicologia , Aceitação pelo Paciente de Cuidados de Saúde/estatística & dados numéricos , Prisões , Modelos de Riscos Proporcionais , Estudos Retrospectivos , Adulto Jovem
8.
Sci Total Environ ; 661: 696-710, 2019 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-30684838

RESUMO

Intensification of grasslands is necessary to meet the increasing demand of livestock products. The application of nitrogen (N) on grasslands affects the N balance therefore the nitrogen use efficiency (NUE). Emissions of nitrous oxide (N2O) are produced due to N fertilisation and low NUE. These emissions depend on the type and rates of N applied. In this study we have compiled data from 5 UK N fertilised grassland sites (Crichton, Drayton, North Wyke, Hillsborough and Pwllpeiran) covering a range of soil types and climates. The experiments evaluated the effect of increasing rates of inorganic N fertiliser provided as ammonium nitrate (AN) or calcium ammonium nitrate (CAN). The following fertiliser strategies were also explored for a rate of 320 kg N ha-1: using the nitrification inhibitor dicyandiamide (DCD), changing to urea as an N source and splitting fertiliser applications. We measured N2O emissions for a full year in each experiment, as well as soil mineral N, climate data, pasture yield and N offtake. N2O emissions were greater at Crichton and North Wyke whereas Drayton, Hillsborough and Pwllpeiran had the smallest emissions. The resulting average emission factor (EF) of 1.12% total N applied showed a range of values for all the sites between 0.6 and 2.08%. NUE depended on the site and for an application rate of 320 kg N ha-1, N surplus was on average higher than 80 kg N ha-1, which is proposed as a maximum by the EU Nitrogen Expert Panel. N2O emissions tended to be lower when urea was applied instead of AN or CAN, and were particularly reduced when using urea with DCD. Finally, correlations between the factors studied showed that total N input was related to Nofftake and Nexcess; while cumulative emissions and EF were related to yield scaled emissions.


Assuntos
Poluentes Atmosféricos/análise , Poluição do Ar/prevenção & controle , Fertilizantes/análise , Nitrogênio/análise , Óxido Nitroso/análise , Agricultura/métodos , Inglaterra , Monitoramento Ambiental , Gases de Efeito Estufa/análise , Irlanda do Norte , Escócia , País de Gales
9.
Phys Rev Lett ; 121(9): 097701, 2018 Aug 31.
Artigo em Inglês | MEDLINE | ID: mdl-30230891

RESUMO

We report on the fabrication of Josephson junctions using the topological crystalline insulator Pb_{0.5}Sn_{0.5}Te as the weak link. The properties of these junctions are characterized and compared to those fabricated with weak links of PbTe, a similar material yet topologically trivial. Most striking is the difference in the ac Josephson effect: junctions made with Pb_{0.5}Sn_{0.5}Te exhibit a rich subharmonic structure consistent with a skewed current-phase relation. This structure is absent in junctions fabricated from PbTe. A discussion is given on the origin of this effect as an indication of novel behavior arising from the topologically nontrivial surface state.

10.
J Laryngol Otol ; 132(7): 642-650, 2018 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-29961434

RESUMO

OBJECTIVES: To assess five-year local control and ultimate local control rates of patients treated for locally advanced T3-4 glottic carcinoma with surgery only, radiotherapy only, or surgery plus radiotherapy. Cancer-specific survival, overall survival and rates of malignancy development were also assessed. METHODS: A retrospective review was conducted on patients from 1967 to 2015, with analysis of local control, ultimate local control, overall survival and cancer-specific survival performed using Kaplan-Meier and Cox regression. RESULTS: Of 169 eligible patients, the majority (59 per cent) were treated with surgery plus radiotherapy, with laryngectomy being the most common surgical procedure. Local control and ultimate local control rates were higher with surgery only (94.1 per cent) and surgery plus radiotherapy (87.9 and 86.8 per cent respectively), compared to radiotherapy only (46.8 and 52.4 per cent) (both p < 0.001). Cancer-specific survival, overall survival and malignancy development did not differ between groups. CONCLUSION: Surgery, with or without radiotherapy, offers significantly higher five-year local control and ultimate local control for patients with advanced glottic carcinoma, compared to radiotherapy only.


Assuntos
Carcinoma/mortalidade , Neoplasias Laríngeas/mortalidade , Laringectomia/mortalidade , Radioterapia/mortalidade , Adulto , Idoso , Idoso de 80 Anos ou mais , Carcinoma/patologia , Carcinoma/terapia , Terapia Combinada , Feminino , Glote/patologia , Humanos , Estimativa de Kaplan-Meier , Neoplasias Laríngeas/patologia , Neoplasias Laríngeas/terapia , Laringectomia/métodos , Masculino , Pessoa de Meia-Idade , Modelos de Riscos Proporcionais , Análise de Regressão , Estudos Retrospectivos , Taxa de Sobrevida , Resultado do Tratamento
11.
Sci Total Environ ; 635: 607-617, 2018 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-29679833

RESUMO

Urine patches and dung pats from grazing livestock create hotspots for production and emission of the greenhouse gas, nitrous oxide (N2O), and represent a large proportion of total N2O emissions in many national agricultural greenhouse gas inventories. As such, there is much interest in developing country specific N2O emission factors (EFs) for excretal nitrogen (EF3, pasture, range and paddock) deposited during gazing. The aims of this study were to generate separate N2O emissions data for cattle derived urine and dung, to provide an evidence base for the generation of a country specific EF for the UK from this nitrogen source. The experiments were also designed to determine the effects of site and timing of application on emissions, and the efficacy of the nitrification inhibitor, dicyandiamide (DCD) on N2O losses. This co-ordinated set of 15 plot-scale, year-long field experiments using static chambers was conducted at five grassland sites, typical of the soil and climatic zones of grazed grassland in the UK. We show that the average urine and dung N2O EFs were 0.69% and 0.19%, respectively, resulting in a combined excretal N2O EF (EF3), of 0.49%, which is <25% of the IPCC default EF3 for excretal returns from grazing cattle. Regression analysis suggests that urine N2O EFs were controlled more by composition than was the case for dung, whilst dung N2O EFs were more related to soil and environmental factors. The urine N2O EF was significantly greater from the site in SW England, and significantly greater from the early grazing season urine application than later applications. Dycandiamide reduced the N2O EF from urine patches by an average of 46%. The significantly lower excretal EF3 than the IPCC default has implications for the UK's national inventory and for subsequent carbon footprinting of UK ruminant livestock products.


Assuntos
Poluentes Atmosféricos/análise , Monitoramento Ambiental , Óxido Nitroso/análise , Urina/química , Agricultura , Poluição do Ar/estatística & dados numéricos , Animais , Bovinos , Inglaterra , Guanidinas , Gado , Solo
12.
Poult Sci ; 96(10): 3586-3592, 2017 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-28938764

RESUMO

Whole turkeys sold in retail outlets are typically processed with added solutions to improve their taste and tenderness. The purpose of this study was to evaluate the nutrient composition of whole turkeys with and without added solution, and to update the nutrient profile of turkey for the USDA National Nutrient Database for Standard Reference. Eleven pairs of turkeys with added solution were obtained from statistically representative retail outlets using a nationwide sampling plan developed for USDA's National Food and Nutrient Analysis Program; 4 pairs of turkeys without added solution were purchased from local food outlets. Turkeys were roasted to an internal temperature of 165°F (74°C). Values of selected nutrients in light and dark meat, including skin, were determined by USDA approved laboratories using quality assurance protocols. Both raw and cooked turkeys, with and without added solution, were compared by one-way and 2-way factorial ANOVA. The results showed a significant interaction for fat (P < 0.0001) and zinc (P = 0.0070) between turkeys that were raw and cooked and those prepared with or without added solution. Fat was higher in raw turkeys with added solution compared to without added solution. Similarly, sodium, phosphorus, and calcium values were significantly higher in turkeys with added solution (P < 0.05) than in turkeys without added solution. Data from this study will be useful for developing strategies to address sodium-related health issues, nutrition monitoring, consumption surveys, and policy development.


Assuntos
Manipulação de Alimentos/métodos , Carne/análise , Animais , Culinária , Paladar , Perus
13.
Travel Med Infect Dis ; 14(2): 131-6, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-26827135

RESUMO

BACKGROUND: Travellers' diarrhoea in military populations is reported ranging from 50 to 70 cases per thousand person months. The UK personnel deployed to the Ebola Outbreak in Sierra Leone during the Ebola outbreak adopted standard measures associated with disease prevention. As part of the infection control measures against transmission of Ebola, personnel also rinsed their hands frequently in 0.05% hypochlorite. This was felt to have reduced the incidence of travellers' diarrhoea in the population and an audit was carried out to test this hypothesis. METHODS: Routine data identified diarrhoea and vomiting cases. A questionnaire sought information on traveller's diarrhoea and hand hygiene in Sierra Leone and Afghanistan. RESULTS: The incidence of Gastro Intestinal Disease for the population ranged from 23.9 Per thousand personnel per month to 74.4 per thousand personnel per month (mean 55.1 cases per thousand personnel per month). This included 4 headline outbreaks which accounted for 156 of the total number of 243 cases in the period of the deployment. The mean daily number of hand washes in Sierra Leone as reported in a survey was 17.02 (SD 8.2) and for Afghanistan was 9.06 (6.88). The mean difference was 7.94 (t 0.64 p < 0.0001.) CONCLUSION: The gastro intestinal disease incidence appeared to be at the lower end of the range reported by other groups in an environment with, arguably, a greater risk of infection. Force health protection policies were similar between Sierra Leone and Afghanistan excepting the frequency with which hands were rinsed or washed. We recommend that hand washing stations are placed at every office and communal area and not just at the dining facility in order to minimise the incidence of travellers' diarrhoea on future operations.


Assuntos
Gastroenterite/prevenção & controle , Desinfecção das Mãos/normas , Higiene das Mãos/métodos , Militares , Adolescente , Adulto , Afeganistão/epidemiologia , Feminino , Gastroenterite/epidemiologia , Higiene das Mãos/normas , Humanos , Masculino , Pessoa de Meia-Idade , Serra Leoa/epidemiologia , Dermatopatias/epidemiologia , Hipoclorito de Sódio/normas , Inquéritos e Questionários , Adulto Jovem
14.
Meat Sci ; 110: 236-44, 2015 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-26280470

RESUMO

Beef nutrition research has become increasingly important domestically and internationally for the beef industry and its consumers. The objective of this study was to analyze the nutrient composition of ten beef loin and round cuts to update the nutrient data in the USDA National Nutrient Database for Standard Reference. Seventy-two carcasses representing a national composite of Yield Grade, Quality Grade, sex classification, and genetic type were identified from six regions across the U.S. Beef short loins, strip loins, tenderloins, inside rounds, and eye of rounds (NAMP # 173, 175, 190A, 169A, and 171C) were collected from the selected carcasses and shipped to three university meat laboratories for storage, retail fabrication, and raw/cooked analysis of nutrients. Sample homogenates from each animal were analyzed for proximate composition. These data provide updated information regarding the nutrient status of beef, in addition, to determining the influence of Quality Grade, Yield Grade, and sex classification on nutrient composition.


Assuntos
Culinária , Bases de Dados Factuais , Análise de Alimentos , Carne/análise , Fenômenos Fisiológicos da Nutrição Animal , Animais , Composição Corporal/genética , Bovinos , Melhoria de Qualidade , Padrões de Referência
15.
Dentomaxillofac Radiol ; 44(5): 20140347, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-25651274

RESUMO

OBJECTIVES: The aim of the present study was to analyse the mineralization pattern of enamel and dentin in patients affected by X-linked hypophosphatemic rickets (XLHR) using micro-CT (µCT), and to associate enamel and dentin mineralization in primary and permanent teeth with tooth position, gender and the presence/absence of this disease. METHODS: 19 teeth were collected from 5 individuals from the same family, 1 non-affected by XLHR and 4 affected by XLHR. Gender, age, tooth position (anterior/posterior) and tooth type (deciduous/permanent) were recorded for each patient. Following collection, teeth were placed in 0.1% thymol solution until µCT scan. Projection images were reconstructed and analysed. A plot profile describing the greyscale distance relationship in µCT images was achieved through a line bisecting each tooth in a region with the presence of enamel and dentin. The enamel and dentin mineralization densities were measured and compared. Univariate ANOVA and post hoc Tukey tests were used for all comparisons. RESULTS: Teeth of all affected patients presented dentin with a different mineralization pattern compared with the teeth of healthy patients with dentin defects observed next to the pulp chambers. Highly significant differences were found for gray values between anterior and posterior teeth (p < 0.05), affected and non-affected (p < 0.05), as well as when position and disease status were considered (p < 0.05). CONCLUSIONS: In conclusion, the mineralization patterns of dentin differed when comparing teeth from patients with and without FHR, mainly next to pulp chambers where areas with porosity and consequently lower mineral density and dentin defects were found.


Assuntos
Raquitismo Hipofosfatêmico Familiar/diagnóstico por imagem , Calcificação de Dente/fisiologia , Microtomografia por Raio-X , Adolescente , Adulto , Criança , Esmalte Dentário/diagnóstico por imagem , Esmalte Dentário/patologia , Dentina/diagnóstico por imagem , Dentina/patologia , Raquitismo Hipofosfatêmico Familiar/fisiopatologia , Feminino , Humanos , Masculino
16.
Nat Commun ; 6: 5838, 2015 Jan 06.
Artigo em Inglês | MEDLINE | ID: mdl-25562690

RESUMO

The electronic properties of graphene are described by a Dirac Hamiltonian with a four-fold symmetry of spin and valley. This symmetry may yield novel fractional quantum Hall (FQH) states at high magnetic field depending on the relative strength of symmetry-breaking interactions. However, observing such states in transport remains challenging in graphene, as they are easily destroyed by disorder. In this work, we observe in the first two Landau levels the two-flux composite-fermion sequences of FQH states between each integer filling factor. In particular, the odd-numerator fractions appear between filling factors 1 and 2, suggesting a broken-valley symmetry, consistent with our observation of a gap at charge neutrality and zero field. Contrary to our expectations, the evolution of gaps in a parallel magnetic field suggests that states in the first Landau level are not spin-polarized even up to very large out-of-plane fields.

17.
Clin Radiol ; 69(12): e562-7, 2014 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-25446326

RESUMO

AIM: To identify adult patients with single-ventricle congenital heart disease and Fontan procedure palliation who have been misdiagnosed with or incompletely evaluated for pulmonary embolism. Additionally, this study was designed to demonstrate that simultaneous, dual-injection of contrast medium into an upper and lower extremity vein is superior to single-injection protocols for CT angiography (CTA) of the chest in this population. MATERIALS AND METHODS: Patients included in the study were retrospectively selected from the Adult Congenital Heart Disease (ACHD) database. Search criteria included history of Fontan palliation and available chest CT examination. Patients were evaluated for (1) type of congenital heart disease and prior operations;(2) indication for initial CT evaluation;(3) route of contrast medium administration for the initial CT examination and resulting diagnosis;(4) whether or not anticoagulation therapy was initiated; and (5) final diagnosis and treatment plan.Results: The query of the ACHD database resulted in 28 individuals or patients with Fontan palliation (superior and inferior venae cavae anastomosed to the pulmonary arteries). Of these, 19 patients with Fontan physiology underwent CTA of the pulmonary circulation, and 17 had suboptimal imaging studies. Unfortunately, seven of these 17 patients (41%) were started on anticoagulation therapy due to a diagnosis of pulmonary embolism that was later excluded. CONCLUSION: Patients with single-ventricle/Fontan physiology are at risk of thromboembolic disease. Therefore, studies evaluating their complex anatomy must be performed with the optimal imaging protocol to ensure diagnostic accuracy, which is best achieved with dual-injection of an upper and lower extremity central vein.


Assuntos
Angiografia/métodos , Técnica de Fontan/efeitos adversos , Cardiopatias Congênitas/cirurgia , Artéria Pulmonar/diagnóstico por imagem , Embolia Pulmonar/diagnóstico por imagem , Intensificação de Imagem Radiográfica/métodos , Tomografia Computadorizada por Raios X/métodos , Adulto , Meios de Contraste , Diagnóstico Diferencial , Feminino , Humanos , Iohexol , Masculino , Cuidados Paliativos , Complicações Pós-Operatórias/diagnóstico por imagem , Complicações Pós-Operatórias/etiologia , Embolia Pulmonar/etiologia , Reprodutibilidade dos Testes , Estudos Retrospectivos , Adulto Jovem
18.
Artigo em Inglês | MEDLINE | ID: mdl-25314547

RESUMO

We present recent results of equation-of-state (EOS) measurements of shocked silica (SiO_{2}) aerogel foam at the OMEGA laser facility. Silica aerogel is an important low-density pressure standard used in many high energy density experiments, including the novel technique of shock and release. Due to its many applications, it has been a heavily studied material and has a well-known Hugoniot curve. This work then complements the velocity and pressure measurements with additional temperature data providing the full EOS information within the warm dense matter regime for the temperature interval of 1-15 eV and shock velocities between 10 and 40 km/s corresponding to shock pressures of 0.3-2 Mbar. The experimental results were compared with hydrodynamic simulations and EOS models. We found that the measured temperature was systematically lower than suggested by theoretical calculations. Simulations provide a possible explanation that the emission measured by optical pyrometry comes from a radiative precursor rather than from the shock front, which could have important implications for such measurements.


Assuntos
Teste de Materiais , Pressão , Dióxido de Silício/química , Temperatura , Géis , Interferometria , Lasers
19.
Phys Rev Lett ; 112(19): 196601, 2014 May 16.
Artigo em Inglês | MEDLINE | ID: mdl-24877955

RESUMO

We report on transport measurements of dual-gated, single-layer graphene devices in the quantum Hall regime, allowing for independent control of the filling factors in adjoining regions. Progress in device quality allows us to study scattering between edge states when the fourfold degeneracy of the Landau level is lifted by electron correlations, causing edge states to be spin and/or valley polarized. In this new regime, we observe a dramatic departure from the equilibration seen in more disordered devices: edge states with opposite spins propagate without mixing. As a result, the degree of equilibration inferred from transport can reveal the spin polarization of the ground state at each filling factor. In particular, the first Landau level is shown to be spin polarized at half filling, providing an independent confirmation of a conclusion of Young et al. [Nat. Phys. 8, 550 (2012). The conductance in the bipolar regime is strongly suppressed, indicating that copropagating edge states, even with the same spin, do not equilibrate along PN interfaces. We attribute this behavior to the formation of an insulating ν = 0 stripe at the PN interface.

20.
J Theor Biol ; 355: 140-50, 2014 Aug 21.
Artigo em Inglês | MEDLINE | ID: mdl-24727187

RESUMO

In India, the identity of men who have sex with men (MSM) is closely related to the role taken in anal sex (insertive, receptive or both), but little is known about sexual mixing between identity groups. Both role segregation (taking only the insertive or receptive role) and the extent of assortative (within-group) mixing are known to affect HIV epidemic size in other settings and populations. This study explores how different possible mixing scenarios, consistent with behavioural data collected in Bangalore, south India, affect both the HIV epidemic, and the impact of a targeted intervention. Deterministic models describing HIV transmission between three MSM identity groups (mostly insertive Panthis/Bisexuals, mostly receptive Kothis/Hijras and versatile Double Deckers), were parameterised with behavioural data from Bangalore. We extended previous models of MSM role segregation to allow each of the identity groups to have both insertive and receptive acts, in differing ratios, in line with field data. The models were used to explore four different mixing scenarios ranging from assortative (maximising within-group mixing) to disassortative (minimising within-group mixing). A simple model was used to obtain insights into the relationship between the degree of within-group mixing, R0 and equilibrium HIV prevalence under different mixing scenarios. A more complex, extended version of the model was used to compare the predicted HIV prevalence trends and impact of an HIV intervention when fitted to data from Bangalore. With the simple model, mixing scenarios with increased amounts of assortative (within-group) mixing tended to give rise to a higher R0 and increased the likelihood that an epidemic would occur. When the complex model was fit to HIV prevalence data, large differences in the level of assortative mixing were seen between the fits identified using different mixing scenarios, but little difference was projected in future HIV prevalence trends. An oral pre-exposure prophylaxis (PrEP) intervention was modelled, targeted at the different identity groups. For intervention strategies targeting the receptive or receptive and versatile MSM together, the overall impact was very similar for different mixing patterns. However, for PrEP scenarios targeting insertive or versatile MSM alone, the overall impact varied considerably for different mixing scenarios; more impact was achieved with greater levels of disassortative mixing.


Assuntos
Infecções por HIV/epidemiologia , Infecções por HIV/transmissão , HIV-1 , Homossexualidade Masculina , Modelos Biológicos , Humanos , Índia/epidemiologia , Masculino , Prevalência
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...