Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 26
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
Nat Commun ; 7: 11201, 2016 Apr 11.
Artigo em Inglês | MEDLINE | ID: mdl-27062914

RESUMO

Simulations predict that hot super-Earth sized exoplanets can have their envelopes stripped by photoevaporation, which would present itself as a lack of these exoplanets. However, this absence in the exoplanet population has escaped a firm detection. Here we demonstrate, using asteroseismology on a sample of exoplanets and exoplanet candidates observed during the Kepler mission that, while there is an abundance of super-Earth sized exoplanets with low incident fluxes, none are found with high incident fluxes. We do not find any exoplanets with radii between 2.2 and 3.8 Earth radii with incident flux above 650 times the incident flux on Earth. This gap in the population of exoplanets is explained by evaporation of volatile elements and thus supports the predictions. The confirmation of a hot-super-Earth desert caused by evaporation will add an important constraint on simulations of planetary systems, since they must be able to reproduce the dearth of close-in super-Earths.

2.
Rev Sci Instrum ; 86(6): 063107, 2015 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-26133828

RESUMO

We describe the design of and the first commissioning experiments with a newly constructed electrostatic storage ring named SAPHIRA (Storage Ring in Aarhus for PHoton-Ion Reaction Analysis). With an intense beam of Cu(-) at 4 keV, the storage ring is characterized in terms of the stored ion beam decay rate, the longitudinal spreading of an injected ion bunch, as well as the direct measurements of the transverse spatial distributions under different conditions of storage. The ion storage stability in SAPHIRA was investigated systematically in a selected region of its electrical configuration space.

3.
Nature ; 477(7366): 570-3, 2011 Sep 29.
Artigo em Inglês | MEDLINE | ID: mdl-21918514

RESUMO

Delta Scuti (δSct) stars are opacity-driven pulsators with masses of 1.5-2.5 M⊙, their pulsations resulting from the varying ionization of helium. In less massive stars such as the Sun, convection transports mass and energy through the outer 30 per cent of the star and excites a rich spectrum of resonant acoustic modes. Based on the solar example, with no firm theoretical basis, models predict that the convective envelope in δSct stars extends only about 1 per cent of the radius, but with sufficient energy to excite solar-like oscillations. This was not observed before the Kepler mission, so the presence of a convective envelope in the models has been questioned. Here we report the detection of solar-like oscillations in the δSct star HD187547, implying that surface convection operates efficiently in stars about twice as massive as the Sun, as the ad hoc models predicted.

4.
Science ; 332(6026): 213-6, 2011 Apr 08.
Artigo em Inglês | MEDLINE | ID: mdl-21474754

RESUMO

In addition to its search for extrasolar planets, the NASA Kepler mission provides exquisite data on stellar oscillations. We report the detections of oscillations in 500 solar-type stars in the Kepler field of view, an ensemble that is large enough to allow statistical studies of intrinsic stellar properties (such as mass, radius, and age) and to test theories of stellar evolution. We find that the distribution of observed masses of these stars shows intriguing differences to predictions from models of synthetic stellar populations in the Galaxy.

5.
Science ; 332(6026): 216-8, 2011 Apr 08.
Artigo em Inglês | MEDLINE | ID: mdl-21474755

RESUMO

Hierarchical triple systems comprise a close binary and a more distant component. They are important for testing theories of star formation and of stellar evolution in the presence of nearby companions. We obtained 218 days of Kepler photometry of HD 181068 (magnitude of 7.1), supplemented by ground-based spectroscopy and interferometry, which show it to be a hierarchical triple with two types of mutual eclipses. The primary is a red giant that is in a 45-day orbit with a pair of red dwarfs in a close 0.9-day orbit. The red giant shows evidence for tidally induced oscillations that are driven by the orbital motion of the close pair. HD 181068 is an ideal target for studies of dynamical evolution and testing tidal friction theories in hierarchical triple systems.

6.
Science ; 332(6026): 205, 2011 Apr 08.
Artigo em Inglês | MEDLINE | ID: mdl-21415318

RESUMO

Stellar interiors are inaccessible through direct observations. For this reason, helioseismologists made use of the Sun's acoustic oscillation modes to tune models of its structure. The quest to detect modes that probe the solar core has been ongoing for decades. We report the detection of mixed modes penetrating all the way to the core of an evolved star from 320 days of observations with the Kepler satellite. The period spacings of these mixed modes are directly dependent on the density gradient between the core region and the convective envelope.

7.
Science ; 325(5941): 709, 2009 Aug 07.
Artigo em Inglês | MEDLINE | ID: mdl-19661420

RESUMO

Ten days of photometric data were obtained during the commissioning phase of the Kepler mission, including data for the previously known giant transiting exoplanet HAT-P-7b. The data for HAT-P-7b show a smooth rise and fall of light from the planet as it orbits its star, punctuated by a drop of 130 +/- 11 parts per million in flux when the planet passes behind its star. We interpret this as the phase variation of the dayside thermal emission plus reflected light from the planet as it orbits its star and is occulted. The depth of the occultation is similar in photometric precision to the detection of a transiting Earth-size planet for which the mission was designed.

8.
Br J Surg ; 90(5): 575-80, 2003 May.
Artigo em Inglês | MEDLINE | ID: mdl-12734865

RESUMO

BACKGROUND: Perineal wounds following abdominoperineal resection (APR), for persistent or locally recurrent anal cancer, are associated with poor healing secondary to irradiation therapy. The results of APR combined with a vertical rectus abdominis musculocutaneous (VRAM) flap transposed transpelvically to cover the perineal defect are presented. METHODS: Between 1994 and 2000, 105 patients were diagnosed and treated for anal cancer. Twenty-two (21 per cent) underwent a salvage operation owing to persistent or locally recurrent disease. In eight patients, before 1996, the perineum was closed primarily with serious wound complications in five. In the final 14 patients, primary perineal reconstruction with a VRAM flap was performed. RESULTS: Median age was 65.5 (range 45-78) years. Median follow-up was 14.5 (range 3-41) months. There were no flap-related complications and primary healing was achieved in all patients. Median hospital stay was 17 (range 14-72) days. There were two major complications related to the laparotomy and abdominal closure. CONCLUSION: Combining the salvage operation with a VRAM flap facilitates primary healing after surgical treatment for persistent or locally recurrent anal cancer. A single-stage primary reconstructive procedure is feasible, with an acceptable complication rate and high level of patient satisfaction.


Assuntos
Neoplasias do Ânus/cirurgia , Terapia de Salvação , Retalhos Cirúrgicos , Idoso , Neoplasias do Ânus/tratamento farmacológico , Neoplasias do Ânus/radioterapia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Recidiva Local de Neoplasia , Estadiamento de Neoplasias , Satisfação do Paciente , Complicações Pós-Operatórias/etiologia , Deiscência da Ferida Operatória/etiologia , Resultado do Tratamento , Incontinência Urinária por Estresse/etiologia , Cicatrização
9.
Phys Rev Lett ; 84(1): 47-50, 2000 Jan 03.
Artigo em Inglês | MEDLINE | ID: mdl-11015831

RESUMO

The Coster-Kronig lines associated with Ar2s decay have been resolved within the natural linewidth of the 2s hole for the first time. This was possible by a new spectroscopic technique, relying on resonance enhanced double photoionization, Auger-threshold photoelectron coincidence spectroscopy. Contrary to standard Auger spectroscopy, this technique can filter out weak components in Auger spectra corresponding to a well-defined inner-shell state and, furthermore, can achieve a resolution no longer limited by the lifetime of the inner-shell hole.

10.
Ugeskr Laeger ; 162(14): 2032-6, 2000 Apr 03.
Artigo em Dinamarquês | MEDLINE | ID: mdl-10815518

RESUMO

Patients and GPs were asked about necessity and possible prevention of contacts to the out of hour service. 4187 (83.9%) of the GP questionnaires and 1493 (52.3%) of the patient questionnaires were returned. According to the GPs 25% of the contacts were not necessary and 5% were not necessary according to the patients. Patients and GPs agreed that contacts concerning old people were most necessary. GPs assessed contacts concerning children relatively more necessary. Patients assessed contacts concerning middle-aged relatively more necessary. Frequent users were assessed less necessary according to GPs but more necessary according to the users themselves. Many contacts could have been prevented according to both GPs and patients--especially within the first five hours of the service. Concordance between a patient's and a GPs answer was bad (kappa = 0.0-0.2). Concordance between the GPs answering the phone and the GPs examining the patient was only slightly better (kappa = 0.1-0.3).


Assuntos
Serviços Médicos de Emergência , Medicina de Família e Comunidade , Pacientes , Médicos de Família , Encaminhamento e Consulta , Adolescente , Adulto , Fatores Etários , Idoso , Atitude do Pessoal de Saúde , Criança , Dinamarca , Serviços Médicos de Emergência/estatística & dados numéricos , Estudos de Avaliação como Assunto , Medicina de Família e Comunidade/estatística & dados numéricos , Mau Uso de Serviços de Saúde , Humanos , Pessoa de Meia-Idade , Pacientes/psicologia , Médicos de Família/psicologia , Encaminhamento e Consulta/estatística & dados numéricos , Inquéritos e Questionários , Recursos Humanos
11.
Scand J Plast Reconstr Surg Hand Surg ; 34(1): 15-20, 2000 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-10756571

RESUMO

The effect of topical cod liver oil ointment on the rate of wound epithelialisation and neovascularisation was studied using the hairless mouse ear wound model (experiment I). The effect of local application of vitamin A in increasing concentrations was tested in the same model (experiment II). Experiment I: Bilateral standardised full thickness dermal wounds were created on the ears of 42 mice divided into three groups: group I: 25% cod liver oil ointment (n = 10) applied topically to one ear and vehicle (vaseline) to the other; group II: 25% cod liver oil ointment (n = 10) and saline; and group III: vehicle (n = 22) and saline. Experiment II: Using the same model and procedures wounds were made on 12 mice randomised to vitamin A treatment in various doses (250-3000 IU/g) on one ear and vehicle (vaseline) on the other ear. Using in-vivo microscopy and digitised planimetry, wound epithelialisation and neovascularisation were measured at regular intervals until the processes were complete. Wounds treated with 25% cod liver oil ointment epithelialized significantly (p < 0.05) faster (mean (SEM) 8.9 (0.7) days) than control ears treated with vehicle alone (13.9 (1.9) days). Neovascularisation developed significantly faster (p < 0.01) in the ears treated with cod liver oil ointment (22.5 (1.3) days) compared with their vehicle control (29.1 (0.6) days). Neovascularisation was also significantly (p < 0.05) faster in the ears treated with cod liver oil ointment (23.1 (1.4) days) than in those treated with saline (26.8 (1.1) days). There was no significant difference in speed of epithelialisation between cod liver oil ointment and saline. The vitamin A dose study showed that epithelialisation and neovascularisation of the vitamin A treated wounds pass at the same rate as wounds treated with cod liver oil ointment. In conclusion, topical 25% cod liver oil ointment significantly accelerated both the epithelial and the vascular component of healing compared with saline. Vitamin A seems to have an important role in accelerating wound healing and could be the active component in cod liver oil.


Assuntos
Óleo de Fígado de Bacalhau/uso terapêutico , Cicatrização , Animais , Estudos de Avaliação como Assunto , Camundongos , Camundongos Pelados , Pomadas , Distribuição Aleatória
14.
Acta Derm Venereol ; 67(6): 523-5, 1987.
Artigo em Inglês | MEDLINE | ID: mdl-2451380

RESUMO

During the years 1977-1986 five patients were referred to the Department of Plastic Surgery. University Hospital, Arhus, for treatment of carcinomas occurring in the skin on the sites previously treated with Grenz rays for benign dermatoses. Grenz ray treatment had been given for eight to nineteen years. The dose given, in one case, was very extensive. Otherwise a dose between 10,000 rad (100 Gy) and 29,300 rad (293 Gy) was given. The tumours were squamous cell carcinomas in four cases and basal cell carcinoma in one case. One person developed both squamous and basal cell carcinomas. The tumours behaved aggressively and in one young patient the dura and the parietal bone had to be replaced by tensor fasciae latae graft and a free latissimus dorsi flap. None of the patients had been exposed to other known carcinogens. Caution in applying Grenz ray treatment is stressed.


Assuntos
Carcinoma Basocelular/etiologia , Carcinoma de Células Escamosas/etiologia , Neoplasias Induzidas por Radiação/etiologia , Psoríase/radioterapia , Radioterapia/efeitos adversos , Terapia por Raios X/efeitos adversos , Adulto , Feminino , Humanos , Masculino , Pessoa de Meia-Idade
17.
Ugeskr Laeger ; 148(19): 1148-9, 1986 May 05.
Artigo em Dinamarquês | MEDLINE | ID: mdl-12187948

RESUMO

Thirty-one patients were operated on because of pressure sores. Twenty-five of these were investigated by means of an enquete. Twenty-two patients replied. In 9 of 22 patients recurrence of pressure sores took place during the observation period, the mean observation time being 35 months. It is concluded that operative treatment of pressure sores, with the methods employed here can be recommended when the conservative treatment is protracted, or the conservative treatment does not result in improvement, provided that the patient is fully aware that consistent relief of pressure is necessary in the postoperative period and the general condition of the patient permits this. Special attention is necessary in patients with repeated recurrences of pressure sores, to ensure that the aforementioned conditions are fulfilled, before surgical treatment. The treatment of repeated recurrences of pressure sores involves many days of hospitalisation, and therefore very high costs.


Assuntos
Úlcera por Pressão/cirurgia , Adulto , Idoso , Feminino , Seguimentos , Humanos , Tempo de Internação , Masculino , Pessoa de Meia-Idade , Recidiva , Inquéritos e Questionários , Resultado do Tratamento
18.
Scand J Plast Reconstr Surg ; 20(1): 119-21, 1986.
Artigo em Inglês | MEDLINE | ID: mdl-3775280

RESUMO

Giant incisional hernias are treated in many different ways involving risks and various degrees of mutilation. We prefer the use of polypropylene mesh (PPM) which is manufactured as Prolene or Marlex mesh. It is easy to handle, has great tensile strength and produces minimum tissue reaction. These qualities make PPM a good substitute for abdominal fascia and the procedure becomes simpler and less extensive than with the use of dermal grafts, flap transfers or other methods. This series consists of twenty-four patients. The results were good in 20 patients (85%). Recurrence of the hernia occurred in two patients (7.5%) and weakness of the abdominal muscles in two others.


Assuntos
Herniorrafia , Polietilenos , Polipropilenos , Cirurgia Plástica/métodos , Telas Cirúrgicas , Abdome/cirurgia , Adulto , Idoso , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Complicações Pós-Operatórias/cirurgia
19.
Artigo em Inglês | MEDLINE | ID: mdl-3869421

RESUMO

A patient with angiosarcoma on the lower leg is presented. The lesion resembled primarily an atypical varicose ulcer, but was immediately suspected of malignancy. Four biopsies could not confirm our suspicion. Only after total excision of the area the diagnosis angiosarcoma was established. This indicates that deep biopsies should be taken from all parts of a tumour suspected of this type of malignant disease.


Assuntos
Hemangiossarcoma/patologia , Perna (Membro) , Neoplasias Cutâneas/patologia , Pele/patologia , Diagnóstico Diferencial , Humanos , Masculino , Pessoa de Meia-Idade
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...