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1.
Int J Tuberc Lung Dis ; 27(9): 658-667, 2023 09 01.
Artigo em Inglês | MEDLINE | ID: mdl-37608484

RESUMO

BACKGROUND: The aim of these clinical standards is to aid the diagnosis and management of asthma in low-resource settings in low- and middle-income countries (LMICs).METHODS: A panel of 52 experts in the field of asthma in LMICs participated in a two-stage Delphi process to establish and reach a consensus on the clinical standards.RESULTS: Eighteen clinical standards were defined: Standard 1, Every individual with symptoms and signs compatible with asthma should undergo a clinical assessment; Standard 2, In individuals (>6 years) with a clinical assessment supportive of a diagnosis of asthma, a hand-held spirometry measurement should be used to confirm variable expiratory airflow limitation by demonstrating an acute response to a bronchodilator; Standard 3, Pre- and post-bronchodilator spirometry should be performed in individuals (>6 years) to support diagnosis before treatment is commenced if there is diagnostic uncertainty; Standard 4, Individuals with an acute exacerbation of asthma and clinical signs of hypoxaemia or increased work of breathing should be given supplementary oxygen to maintain saturation at 94-98%; Standard 5, Inhaled short-acting beta-2 agonists (SABAs) should be used as an emergency reliever in individuals with asthma via an appropriate spacer device for metered-dose inhalers; Standard 6, Short-course oral corticosteroids should be administered in appropriate doses to individuals having moderate to severe acute asthma exacerbations (minimum 3-5 days); Standard 7, Individuals having a severe asthma exacerbation should receive emergency care, including oxygen therapy, systemic corticosteroids, inhaled bronchodilators (e.g., salbutamol with or without ipratropium bromide) and a single dose of intravenous magnesium sulphate should be considered; Standard 8, All individuals with asthma should receive education about asthma and a personalised action plan; Standard 9, Inhaled medications (excluding dry-powder devices) should be administered via an appropriate spacer device in both adults and children. Children aged 0-3 years will require the spacer to be coupled to a face mask; Standard 10, Children aged <5 years with asthma should receive a SABA as-needed at step 1 and an inhaled corticosteroid (ICS) to cover periods of wheezing due to respiratory viral infections, and SABA as-needed and daily ICS from step 2 upwards; Standard 11, Children aged 6-11 years with asthma should receive an ICS taken whenever an inhaled SABA is used; Standard 12, All adolescents aged 12-18 years and adults with asthma should receive a combination inhaler (ICS and rapid onset of action long-acting beta-agonist [LABA] such as budesonide-formoterol), where available, to be used either as-needed (for mild asthma) or as both maintenance and reliever therapy, for moderate to severe asthma; Standard 13, Inhaled SABA alone for the management of patients aged >12 years is not recommended as it is associated with increased risk of morbidity and mortality. It should only be used where there is no access to ICS.The following standards (14-18) are for settings where there is no access to inhaled medicines. Standard 14, Patients without access to corticosteroids should be provided with a single short course of emergency oral prednisolone; Standard 15, Oral SABA for symptomatic relief should be used only if no inhaled SABA is available. Adjust to the individual's lowest beneficial dose to minimise adverse effects; Standard 16, Oral leukotriene receptor antagonists (LTRA) can be used as a preventive medication and is preferable to the use of long-term oral systemic corticosteroids; Standard 17, In exceptional circumstances, when there is a high risk of mortality from exacerbations, low-dose oral prednisolone daily or on alternate days may be considered on a case-by-case basis; Standard 18. Oral theophylline should be restricted for use in situations where it is the only bronchodilator treatment option available.CONCLUSION: These first consensus-based clinical standards for asthma management in LMICs are intended to help clinicians provide the most effective care for people in resource-limited settings.


Assuntos
Asma , Países em Desenvolvimento , Adolescente , Adulto , Criança , Humanos , Broncodilatadores/uso terapêutico , Asma/diagnóstico , Asma/tratamento farmacológico , Albuterol , Prednisolona
2.
Phys Rev Lett ; 129(6): 061104, 2022 Aug 05.
Artigo em Inglês | MEDLINE | ID: mdl-36018635

RESUMO

We report on a search for compact binary coalescences where at least one binary component has a mass between 0.2 M_{⊙} and 1.0 M_{⊙} in Advanced LIGO and Advanced Virgo data collected between 1 April 2019 1500 UTC and 1 October 2019 1500 UTC. We extend our previous analyses in two main ways: we include data from the Virgo detector and we allow for more unequal mass systems, with mass ratio q≥0.1. We do not report any gravitational-wave candidates. The most significant trigger has a false alarm rate of 0.14 yr^{-1}. This implies an upper limit on the merger rate of subsolar binaries in the range [220-24200] Gpc^{-3} yr^{-1}, depending on the chirp mass of the binary. We use this upper limit to derive astrophysical constraints on two phenomenological models that could produce subsolar-mass compact objects. One is an isotropic distribution of equal-mass primordial black holes. Using this model, we find that the fraction of dark matter in primordial black holes in the mass range 0.2 M_{⊙}

3.
Clin Nutr ; 41(9): 2025-2030, 2022 09.
Artigo em Inglês | MEDLINE | ID: mdl-35973395

RESUMO

BACKGROUND: A gluten-free diet (GFD) is the main therapy for non-coeliac gluten sensitivity (NCGS). However, the availability of novel enzymes with the ability to digest gluten could represent a therapeutic opportunity for NCGS patients to avoid a GFD. AIMS: To evaluate the controlled reintroduction of gluten with or without the endopeptidase P1016 in NCGS patients. METHODS: This is a randomized, double-blind, placebo-controlled monocentric study, Registered under ClinicalTrials.gov Identifier no. NCT01864993. Gluten was reintroduced incrementally over a 3-week period under nutritional control. NCGS patients were randomized into two groups and administered P1016 or placebo during gluten reintroduction. We evaluated symptoms (visual analogue scale, VAS), quality of life (SF-36) and mental health symptoms (SCL-90) on a weekly basis. RESULTS: We enrolled a total 23 patients who were allocated to a placebo group (n = 11, age 38.4 ± 2.9) or an intervention group (n = 12, age 39.5 ± 3.1). No effect of P1016 on symptoms was found. During gluten reintroduction, patients reported a significant increase in abdominal pain and a worsening of stool consistency. Furthermore, no differences were found between the groups regarding SCL-90 and SF-36 scores. CONCLUSIONS: Our results demonstrate a lack of effect of P1016 in the management of NCGS patients and the possible reintroduction of gluten.


Assuntos
Doença Celíaca , Glutens , Adulto , Dieta Livre de Glúten , Glutens/efeitos adversos , Humanos , Prolina , Prolil Oligopeptidases , Qualidade de Vida
4.
Andes Pediatr ; 93(1): 43-52, 2022 Feb.
Artigo em Espanhol | MEDLINE | ID: mdl-35506775

RESUMO

OBJECTIVE: to analyze the associations between breastfeeding duration and mixed feeding (breast milk and formula) with obesity, cardiometabolic risk (WHtR), body fat, and dietary and physical activity risk behaviors in children and adolescents. SUBJECTS AND METHOD: cross-sectional study carried out with 1,467 students in Costa Rica. An interview was conducted with parents and children to gather information on socioeconomic status, education, dietary and physical activity risk behaviors of the youth, including breastfeeding duration and mixed feeding. Body mass index, waist circumference, and body fat were assessed by bioelectrical impedance analysis and cardiometabolic risk was mea sured with the waist-to-height ratio (WHtR ≥ 0.5) by trained personnel. Descriptive statistics and logistic regression models were applied. RESULTS: the average age was 11.4 ± 2.6 years and 50.9% were male. 55.5% of the population was middle class; 60% were sedentary, and 16% presented obesity. Around 20% were breastfed without the introduction of formula before 6 months, 13% were never breastfed, and more than 60% were breastfed for ≥ 6 months. Those children who were fed only with breast milk or in combination with formula for ≥ 6 months presented a lower percentage of obesity than those who received formula feeding only (60.8 vs 39.2; p < 0.005). Children with cardiometa bolic risk (WHtR ≥ 0.50), unhealthy diet, sedentary lifestyle, and who were fed only with formula are at higher risk of developing obesity (OR = 18.8, 95% CI 13.2-26.0). CONCLUSIONS: these results are consistent with other studies and reinforce the evident protection of breastfeeding against the development of obesity.


Assuntos
Aleitamento Materno , Doenças Cardiovasculares , Adolescente , Criança , Costa Rica/epidemiologia , Estudos Transversais , Feminino , Humanos , Masculino , Obesidade/epidemiologia , Obesidade/prevenção & controle
5.
Andes Pediatr ; 92(4): 526-533, 2021 Aug.
Artigo em Espanhol | MEDLINE | ID: mdl-34652370

RESUMO

INTRODUCTION: Cystic fibrosis (CF) is a multisystemic disease, with high morbidity and mortality, and its early diag nosis improves results. Lung conditions are the main cause of morbidity and mortality and are clo sely related to nutritional status and survival. There is little national information about the liver and gastrointestinal characteristics in pediatric patients with CF. OBJECTIVE: to describe at a gastrointes tinal level, the general, nutritional, and genetic characteristics and the evolution of CF carriers with/ without neonatal screening. PATIENTS AND METHOD: Retrospective study carried out in 4 public referral hospitals in the Metropolitan Region. The diagnosis of CF confirmed with two positive sweat tests (Gibson and Cooke method) was considered as an inclusion criterion. Those patients with unconfir med neonatal screening tests through Immunoreactive Trypsinogen (IRT) or with only one positive sweat test were excluded. Sex, age, nutritional status, date of diagnosis, clinical presentation at the onset, evolution, and therapies received were recorded as clinical variables, and as laboratory ones, genetic study by means of a diagnostic panel with 36 mutations. The STATA 12 software was used for statistical analysis. RESULTS: 127 patients were included. Respiratory manifestations (recurrent obstructive bronchial syndrome and pneumonia) were present in >60% and gastrointestinal ones (mainly malabsorption and malnutrition syndrome) in >80% of patients. On average, diagnostic confirmation took 4 months. The diagnosis guided by IRT was associated with better nutritional outcomes in the evolution of the patient. In 81.1% of the patients, the genetic study was performed. The most frequent mutations were those associated with DF508 (deletion of phenylalanine 508). 5.8% of the patients presented mutations not included in the gene panel used. CONCLUSIONS: Gas trointestinal CF appears with pancreatic, intestinal, and hepatic pathology throughout life. Malnutri tion is a frequently present factor, which worsens the prognosis. The management of gastrointestinal manifestations and malnutrition are relevant to improve the morbidity and mortality of CF patients.


Assuntos
Fibrose Cística/complicações , Fibrose Cística/genética , Desnutrição , Distúrbios Nutricionais/prevenção & controle , Criança , Fibrose Cística/diagnóstico , Regulador de Condutância Transmembrana em Fibrose Cística/genética , Humanos , Recém-Nascido , Triagem Neonatal , Distúrbios Nutricionais/diagnóstico , Distúrbios Nutricionais/etiologia , Estado Nutricional , Estudos Retrospectivos
6.
Phys Rev Lett ; 126(24): 241102, 2021 Jun 18.
Artigo em Inglês | MEDLINE | ID: mdl-34213926

RESUMO

We search for gravitational-wave signals produced by cosmic strings in the Advanced LIGO and Virgo full O3 dataset. Search results are presented for gravitational waves produced by cosmic string loop features such as cusps, kinks, and, for the first time, kink-kink collisions. A template-based search for short-duration transient signals does not yield a detection. We also use the stochastic gravitational-wave background energy density upper limits derived from the O3 data to constrain the cosmic string tension Gµ as a function of the number of kinks, or the number of cusps, for two cosmic string loop distribution models. Additionally, we develop and test a third model that interpolates between these two models. Our results improve upon the previous LIGO-Virgo constraints on Gµ by 1 to 2 orders of magnitude depending on the model that is tested. In particular, for the one-loop distribution model, we set the most competitive constraints to date: Gµâ‰²4×10^{-15}. In the case of cosmic strings formed at the end of inflation in the context of grand unified theories, these results challenge simple inflationary models.

7.
Living Rev Relativ ; 23(1): 3, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33015351

RESUMO

We present our current best estimate of the plausible observing scenarios for the Advanced LIGO, Advanced Virgo and KAGRA gravitational-wave detectors over the next several years, with the intention of providing information to facilitate planning for multi-messenger astronomy with gravitational waves. We estimate the sensitivity of the network to transient gravitational-wave signals for the third (O3), fourth (O4) and fifth observing (O5) runs, including the planned upgrades of the Advanced LIGO and Advanced Virgo detectors. We study the capability of the network to determine the sky location of the source for gravitational-wave signals from the inspiral of binary systems of compact objects, that is binary neutron star, neutron star-black hole, and binary black hole systems. The ability to localize the sources is given as a sky-area probability, luminosity distance, and comoving volume. The median sky localization area (90% credible region) is expected to be a few hundreds of square degrees for all types of binary systems during O3 with the Advanced LIGO and Virgo (HLV) network. The median sky localization area will improve to a few tens of square degrees during O4 with the Advanced LIGO, Virgo, and KAGRA (HLVK) network. During O3, the median localization volume (90% credible region) is expected to be on the order of 10 5 , 10 6 , 10 7 Mpc 3 for binary neutron star, neutron star-black hole, and binary black hole systems, respectively. The localization volume in O4 is expected to be about a factor two smaller than in O3. We predict a detection count of 1 - 1 + 12 ( 10 - 10 + 52 ) for binary neutron star mergers, of 0 - 0 + 19 ( 1 - 1 + 91 ) for neutron star-black hole mergers, and 17 - 11 + 22 ( 79 - 44 + 89 ) for binary black hole mergers in a one-calendar-year observing run of the HLV network during O3 (HLVK network during O4). We evaluate sensitivity and localization expectations for unmodeled signal searches, including the search for intermediate mass black hole binary mergers.

8.
Phys Rev Lett ; 125(10): 101102, 2020 Sep 04.
Artigo em Inglês | MEDLINE | ID: mdl-32955328

RESUMO

On May 21, 2019 at 03:02:29 UTC Advanced LIGO and Advanced Virgo observed a short duration gravitational-wave signal, GW190521, with a three-detector network signal-to-noise ratio of 14.7, and an estimated false-alarm rate of 1 in 4900 yr using a search sensitive to generic transients. If GW190521 is from a quasicircular binary inspiral, then the detected signal is consistent with the merger of two black holes with masses of 85_{-14}^{+21} M_{⊙} and 66_{-18}^{+17} M_{⊙} (90% credible intervals). We infer that the primary black hole mass lies within the gap produced by (pulsational) pair-instability supernova processes, with only a 0.32% probability of being below 65 M_{⊙}. We calculate the mass of the remnant to be 142_{-16}^{+28} M_{⊙}, which can be considered an intermediate mass black hole (IMBH). The luminosity distance of the source is 5.3_{-2.6}^{+2.4} Gpc, corresponding to a redshift of 0.82_{-0.34}^{+0.28}. The inferred rate of mergers similar to GW190521 is 0.13_{-0.11}^{+0.30} Gpc^{-3} yr^{-1}.

9.
Trop Biomed ; 37(2): 318-323, 2020 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-33612801

RESUMO

Domestic mites have been recognized as the most common allergen responsible for respiratory allergy. Herein, we report a case of anaphylaxis due to ingestion of dust mitecontaminated food. A 14-year-old boy presented to the Emergency Department with chest discomfort, wheezing, eyelid angioedema, and urticarial rash twice in a month after eating meals, including tempura fried squids and onion fritters (containing wheat flour, eggs, squid, and onion). Anaphylaxis had been diagnosed and successfully treated. The investigations showed that the patient was sensitive to house dust mites. Positive skin prick-to-prick test response to incriminated flour and negative tests to wheat allergen extract and uncontaminated flour were demonstrated. The microscopic analysis of causative cooking flour identified the presence of Dermatophagoides farinae. During the oral food challenge test, the patient was able to eat tempura-fried squids and onion fritters, made with uncontaminated flour, without any adverse reaction. Hence, oral ingestion of dust mite-contaminated food was the culprit of this severe allergic reaction.


Assuntos
Anafilaxia/etiologia , Dermatophagoides farinae , Contaminação de Alimentos , Adolescente , Angioedema , Animais , Antígenos de Dermatophagoides , Humanos , Masculino , Testes Cutâneos , Tailândia , Triticum , Urticária
10.
Phys Rev Lett ; 123(16): 161102, 2019 Oct 18.
Artigo em Inglês | MEDLINE | ID: mdl-31702344

RESUMO

We present a search for subsolar mass ultracompact objects in data obtained during Advanced LIGO's second observing run. In contrast to a previous search of Advanced LIGO data from the first observing run, this search includes the effects of component spin on the gravitational waveform. We identify no viable gravitational-wave candidates consistent with subsolar mass ultracompact binaries with at least one component between 0.2 M_{⊙}-1.0 M_{⊙}. We use the null result to constrain the binary merger rate of (0.2 M_{⊙}, 0.2 M_{⊙}) binaries to be less than 3.7×10^{5} Gpc^{-3} yr^{-1} and the binary merger rate of (1.0 M_{⊙}, 1.0 M_{⊙}) binaries to be less than 5.2×10^{3} Gpc^{-3} yr^{-1}. Subsolar mass ultracompact objects are not expected to form via known stellar evolution channels, though it has been suggested that primordial density fluctuations or particle dark matter with cooling mechanisms and/or nuclear interactions could form black holes with subsolar masses. Assuming a particular primordial black hole (PBH) formation model, we constrain a population of merging 0.2 M_{⊙} black holes to account for less than 16% of the dark matter density and a population of merging 1.0 M_{⊙} black holes to account for less than 2% of the dark matter density. We discuss how constraints on the merger rate and dark matter fraction may be extended to arbitrary black hole population models that predict subsolar mass binaries.

11.
Phys Rev Lett ; 123(1): 011102, 2019 Jul 03.
Artigo em Inglês | MEDLINE | ID: mdl-31386391

RESUMO

The recent discovery by Advanced LIGO and Advanced Virgo of a gravitational wave signal from a binary neutron star inspiral has enabled tests of general relativity (GR) with this new type of source. This source, for the first time, permits tests of strong-field dynamics of compact binaries in the presence of matter. In this Letter, we place constraints on the dipole radiation and possible deviations from GR in the post-Newtonian coefficients that govern the inspiral regime. Bounds on modified dispersion of gravitational waves are obtained; in combination with information from the observed electromagnetic counterpart we can also constrain effects due to large extra dimensions. Finally, the polarization content of the gravitational wave signal is studied. The results of all tests performed here show good agreement with GR.

12.
Phys Rev Lett ; 122(6): 061104, 2019 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-30822067

RESUMO

We analyze the impact of a proposed tidal instability coupling p modes and g modes within neutron stars on GW170817. This nonresonant instability transfers energy from the orbit of the binary to internal modes of the stars, accelerating the gravitational-wave driven inspiral. We model the impact of this instability on the phasing of the gravitational wave signal using three parameters per star: an overall amplitude, a saturation frequency, and a spectral index. Incorporating these additional parameters, we compute the Bayes factor (lnB_{!pg}^{pg}) comparing our p-g model to a standard one. We find that the observed signal is consistent with waveform models that neglect p-g effects, with lnB_{!pg}^{pg}=0.03_{-0.58}^{+0.70} (maximum a posteriori and 90% credible region). By injecting simulated signals that do not include p-g effects and recovering them with the p-g model, we show that there is a ≃50% probability of obtaining similar lnB_{!pg}^{pg} even when p-g effects are absent. We find that the p-g amplitude for 1.4 M_{⊙} neutron stars is constrained to less than a few tenths of the theoretical maximum, with maxima a posteriori near one-tenth this maximum and p-g saturation frequency ∼70 Hz. This suggests that there are less than a few hundred excited modes, assuming they all saturate by wave breaking. For comparison, theoretical upper bounds suggest ≲10^{3} modes saturate by wave breaking. Thus, the measured constraints only rule out extreme values of the p-g parameters. They also imply that the instability dissipates ≲10^{51} erg over the entire inspiral, i.e., less than a few percent of the energy radiated as gravitational waves.

13.
Phys Rev Lett ; 121(23): 231103, 2018 Dec 07.
Artigo em Inglês | MEDLINE | ID: mdl-30576173

RESUMO

We present the first Advanced LIGO and Advanced Virgo search for ultracompact binary systems with component masses between 0.2 M_{⊙}-1.0 M_{⊙} using data taken between September 12, 2015 and January 19, 2016. We find no viable gravitational wave candidates. Our null result constrains the coalescence rate of monochromatic (delta function) distributions of nonspinning (0.2 M_{⊙}, 0.2 M_{⊙}) ultracompact binaries to be less than 1.0×10^{6} Gpc^{-3} yr^{-1} and the coalescence rate of a similar distribution of (1.0 M_{⊙}, 1.0 M_{⊙}) ultracompact binaries to be less than 1.9×10^{4} Gpc^{-3} yr^{-1} (at 90% confidence). Neither black holes nor neutron stars are expected to form below ∼1 M_{⊙} through conventional stellar evolution, though it has been proposed that similarly low mass black holes could be formed primordially through density fluctuations in the early Universe and contribute to the dark matter density. The interpretation of our constraints in the primordial black hole dark matter paradigm is highly model dependent; however, under a particular primordial black hole binary formation scenario we constrain monochromatic primordial black hole populations of 0.2 M_{⊙} to be less than 33% of the total dark matter density and monochromatic populations of 1.0 M_{⊙} to be less than 5% of the dark matter density. The latter strengthens the presently placed bounds from microlensing surveys of massive compact halo objects (MACHOs) provided by the MACHO and EROS Collaborations.

14.
Rev. chil. cir ; 70(6): 571-579, dic. 2018. tab, ilus
Artigo em Espanhol | LILACS | ID: biblio-978032

RESUMO

Resumen Introducción: La insuficiencia hepática posoperatoria (IHP) es una causa importante de morbimortalidad posoperatoria en cirugía hepática. Un remanente hepático futuro (RHF) insuficiente es una de las principales causas IHP La asociación de bipartición hepática con ligadura portal para hepatectomía en 2 tiempos (ALPPS) es una técnica relativamente nueva que induce una rápida hipertrofia parenquimatosa reduciendo el tiempo de espera para lograr un volumen hepático adecuado. Nuestro objetivo es comunicar la experiencia y los resultados iniciales de la hepatectomía en 2 tiempos utilizando la técnica de ALLPS. Material y Método: Se incluyeron todos los pacientes en los que se ha realizado una hepatectomía en 2 tiempos utilizando la técnica de ALPPS entre el 1 de junio de 2014 y el 31 de julio de 2016 en la Unidad de Cirugía Digestiva del Hospital Regional de Talca. Resutados: Durante el periodo de estudio, se realizaron 47 hepatectomías en el Hospital Regional de Talca. En 3 casos (6.3%), se realizó una hepatectomía en 2 tiempos utilizando la técnica de ALPPS, en todos ellos se logró una hipertrofia del remanente hepático futuro (RHF) que permitió completar el segundo tiempo sin IHP clínicamente significativa. Conclusión: En nuestra experiencia inicial, la técnica de ALPPS logró aumentar el RHF permitiendo resecar pacientes que inicialmente tenían un RHF insuficiente para ser sometidos a una hepatectomía mayor.


Introduction: Postoperative liver failure (POLF) is a relevant cause of morbimortality after liver surgery. An insufficient future liver remnant (FLR) is one of the main causes of POLF. The association of hepatic bipartition with portal ligation for 2-stage hepatectomy (ALPPS) is a relatively new technique that induces rapid parenchymal hypertrophy reducing the waiting time to achieve adequate FLR. Our aim is to communicate the experience and the initial results of the hepatectomy in 2-stages using the ALLPS technique. Material and Method: All patients in whom a 2-stage hepatectomy using ALPPS technique between June 1, 2014 and July 31, 2016 in the Digestive Surgery Unit of the Hospital Regional of Talca were included. Results: There were 47 hepatectomies performed at the Hospital Regional of Talca. In 3 cases (6.3%), a 2-stage hepatectomy was performed using the ALPPS technique, in all of which a hypertrophy of the future hepatic remnant (RHF) was achieved, which allowed completing the second stage without POLF clinically significant. Conclusion: In our initial experience, the ALPPS technique successfully allowed increase FLR in patients who initially had insufficient FLR to be submitted a major liver resection.


Assuntos
Humanos , Masculino , Feminino , Pessoa de Meia-Idade , Insuficiência Hepática/etiologia , Hepatectomia/efeitos adversos , Hepatectomia/métodos , Neoplasias Hepáticas/cirurgia , Resultado do Tratamento , Neoplasias Hepáticas/complicações
15.
Phys Rev Lett ; 121(16): 161101, 2018 Oct 19.
Artigo em Inglês | MEDLINE | ID: mdl-30387654

RESUMO

On 17 August 2017, the LIGO and Virgo observatories made the first direct detection of gravitational waves from the coalescence of a neutron star binary system. The detection of this gravitational-wave signal, GW170817, offers a novel opportunity to directly probe the properties of matter at the extreme conditions found in the interior of these stars. The initial, minimal-assumption analysis of the LIGO and Virgo data placed constraints on the tidal effects of the coalescing bodies, which were then translated to constraints on neutron star radii. Here, we expand upon previous analyses by working under the hypothesis that both bodies were neutron stars that are described by the same equation of state and have spins within the range observed in Galactic binary neutron stars. Our analysis employs two methods: the use of equation-of-state-insensitive relations between various macroscopic properties of the neutron stars and the use of an efficient parametrization of the defining function p(ρ) of the equation of state itself. From the LIGO and Virgo data alone and the first method, we measure the two neutron star radii as R_{1}=10.8_{-1.7}^{+2.0} km for the heavier star and R_{2}=10.7_{-1.5}^{+2.1} km for the lighter star at the 90% credible level. If we additionally require that the equation of state supports neutron stars with masses larger than 1.97 M_{⊙} as required from electromagnetic observations and employ the equation-of-state parametrization, we further constrain R_{1}=11.9_{-1.4}^{+1.4} km and R_{2}=11.9_{-1.4}^{+1.4} km at the 90% credible level. Finally, we obtain constraints on p(ρ) at supranuclear densities, with pressure at twice nuclear saturation density measured at 3.5_{-1.7}^{+2.7}×10^{34} dyn cm^{-2} at the 90% level.

16.
Phys Rev Lett ; 120(20): 201102, 2018 May 18.
Artigo em Inglês | MEDLINE | ID: mdl-29864331

RESUMO

The detection of gravitational waves with Advanced LIGO and Advanced Virgo has enabled novel tests of general relativity, including direct study of the polarization of gravitational waves. While general relativity allows for only two tensor gravitational-wave polarizations, general metric theories can additionally predict two vector and two scalar polarizations. The polarization of gravitational waves is encoded in the spectral shape of the stochastic gravitational-wave background, formed by the superposition of cosmological and individually unresolved astrophysical sources. Using data recorded by Advanced LIGO during its first observing run, we search for a stochastic background of generically polarized gravitational waves. We find no evidence for a background of any polarization, and place the first direct bounds on the contributions of vector and scalar polarizations to the stochastic background. Under log-uniform priors for the energy in each polarization, we limit the energy densities of tensor, vector, and scalar modes at 95% credibility to Ω_{0}^{T}<5.58×10^{-8}, Ω_{0}^{V}<6.35×10^{-8}, and Ω_{0}^{S}<1.08×10^{-7} at a reference frequency f_{0}=25 Hz.

17.
Living Rev Relativ ; 21(1): 3, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29725242

RESUMO

We present possible observing scenarios for the Advanced LIGO, Advanced Virgo and KAGRA gravitational-wave detectors over the next decade, with the intention of providing information to the astronomy community to facilitate planning for multi-messenger astronomy with gravitational waves. We estimate the sensitivity of the network to transient gravitational-wave signals, and study the capability of the network to determine the sky location of the source. We report our findings for gravitational-wave transients, with particular focus on gravitational-wave signals from the inspiral of binary neutron star systems, which are the most promising targets for multi-messenger astronomy. The ability to localize the sources of the detected signals depends on the geographical distribution of the detectors and their relative sensitivity, and [Formula: see text] credible regions can be as large as thousands of square degrees when only two sensitive detectors are operational. Determining the sky position of a significant fraction of detected signals to areas of 5-[Formula: see text] requires at least three detectors of sensitivity within a factor of [Formula: see text] of each other and with a broad frequency bandwidth. When all detectors, including KAGRA and the third LIGO detector in India, reach design sensitivity, a significant fraction of gravitational-wave signals will be localized to a few square degrees by gravitational-wave observations alone.

18.
Benef Microbes ; 9(4): 541-552, 2018 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-29633642

RESUMO

Little is known about the impact of nutrition on toddler gut microbiota. The plasticity of the toddler gut microbiota indicates that nutritional modulation beyond infancy could potentially impact its maturation. The objective of this study was to determine the effect of consuming Young Child Formula (YCF) supplemented with short chain galactooligosaccharides and long chain fructooligosaccharides (scGOS/lcFOS, ratio 9:1) and Bifidobacterium breve M-16V on the development of the faecal microbiota in healthy toddlers. A cohort of 129 Thai children aged 1-3 years were included in a randomised controlled clinical study. The children were assigned to receive either YCF with 0.95 g/100 ml of scGOS/lcFOS and 1.8×107 cfu/g of B. breve M-16V (Active-YCF) or Control-YCF for 12 weeks. The composition and metabolic activity of the faecal microbiota, and the level of secretory immunoglobulin A were determined in the stool samples. The consumption of Active-YCF increased the proportion of Bifidobacterium (mean 27.3% at baseline to 33.3%, at week 12, P=0.012) with a difference in change from baseline at week 12 between the Active and Control of 7.48% (P=0.030). The consumption of Active-YCF was accompanied with a more acidic intestinal milieu compared to the Control-YCF. The pH value decreased statistically significantly in the Active-YCF group from a median of 7.05 at baseline to 6.79 at week 12 (P<0.001). The consumption of Active-YCF was associated with a softer pudding-like stool consistency compared to the Control-YCF. At week 6 and week 12, the between-group difference in stool consistency was statistically significant (P=0.004 and P<0.001, respectively). A Young Child Formula supplemented with scGOS/lcFOS and B. breve M-16V positively influences the development of the faecal microbiota in healthy toddlers by supporting higher levels of Bifidobacterium. The synbiotic supplementation is also accompanied with a more acidic intestinal milieu and softer stools.


Assuntos
Bifidobacterium breve , Fezes/microbiologia , Microbioma Gastrointestinal/efeitos dos fármacos , Probióticos/farmacologia , Bifidobacterium/crescimento & desenvolvimento , Pré-Escolar , Ácidos Graxos Voláteis/análise , Feminino , Humanos , Concentração de Íons de Hidrogênio , Lactente , Masculino , Prebióticos , Simbióticos
19.
Phys Rev Lett ; 120(9): 091101, 2018 Mar 02.
Artigo em Inglês | MEDLINE | ID: mdl-29547330

RESUMO

The LIGO Scientific and Virgo Collaborations have announced the event GW170817, the first detection of gravitational waves from the coalescence of two neutron stars. The merger rate of binary neutron stars estimated from this event suggests that distant, unresolvable binary neutron stars create a significant astrophysical stochastic gravitational-wave background. The binary neutron star component will add to the contribution from binary black holes, increasing the amplitude of the total astrophysical background relative to previous expectations. In the Advanced LIGO-Virgo frequency band most sensitive to stochastic backgrounds (near 25 Hz), we predict a total astrophysical background with amplitude Ω_{GW}(f=25 Hz)=1.8_{-1.3}^{+2.7}×10^{-9} with 90% confidence, compared with Ω_{GW}(f=25 Hz)=1.1_{-0.7}^{+1.2}×10^{-9} from binary black holes alone. Assuming the most probable rate for compact binary mergers, we find that the total background may be detectable with a signal-to-noise-ratio of 3 after 40 months of total observation time, based on the expected timeline for Advanced LIGO and Virgo to reach their design sensitivity.

20.
Phys Rev Lett ; 120(3): 031104, 2018 Jan 19.
Artigo em Inglês | MEDLINE | ID: mdl-29400511

RESUMO

We present results from the first directed search for nontensorial gravitational waves. While general relativity allows for tensorial (plus and cross) modes only, a generic metric theory may, in principle, predict waves with up to six different polarizations. This analysis is sensitive to continuous signals of scalar, vector, or tensor polarizations, and does not rely on any specific theory of gravity. After searching data from the first observation run of the advanced LIGO detectors for signals at twice the rotational frequency of 200 known pulsars, we find no evidence of gravitational waves of any polarization. We report the first upper limits for scalar and vector strains, finding values comparable in magnitude to previously published limits for tensor strain. Our results may be translated into constraints on specific alternative theories of gravity.

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