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1.
Rev Sci Instrum ; 91(3): 034503, 2020 Mar 01.
Artículo en Inglés | MEDLINE | ID: mdl-32260014

RESUMEN

FIREBIRD-II is a National Science Foundation funded CubeSat mission designed to study the scale size and energy spectrum of relativistic electron microbursts. The mission consists of two identical 1.5 U CubeSats in a low earth polar orbit, each with two solid state detectors that differ only in the size of their geometric factors and fields of view. Having two spacecraft in close orbit allows the scale size of microbursts to be investigated through the intra-spacecraft separation when microbursts are observed simultaneously on each unit. Each detector returns high cadence (10 s of ms) measurements of the electron population from 200 keV to >1 MeV across six energy channels. The energy channels were selected to fill a gap in the observations of the Heavy Ion Large Telescope instrument on the Solar, Anomalous, and Magnetospheric Particle Explorer. FIREBIRD-II has been in orbit for 5 years and continues to return high quality data. After the first month in orbit, the spacecraft had separated beyond the expected scale size of microbursts, so the focus has shifted toward conjunctions with other magnetospheric missions. FIREBIRD-II has addressed all of its primary science objectives, and its long lifetime and focus on conjunctions has enabled additional science beyond the scope of the original mission. This paper presents a brief history of the FIREBIRD mission's science goals, followed by a description of the instrument and spacecraft. The data products are then discussed along with some caveats necessary for proper use of the data.

2.
J Geophys Res Space Phys ; 124(11): 9124-9136, 2019 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-32025458

RESUMEN

We describe a new data product combining the spin-averaged electron flux measurements from the Radiation Belt Storm Probes (RBSP) Energetic Particle Composition and Thermal Plasma (ECT) suite on the National Aeronautics and Space Administration's Van Allen Probes. We describe the methodology used to combine each of the data sets and produce a consistent set of spectra for September 2013 to the present. Three-minute-averaged flux spectra are provided spanning energies from 15 eV up to 20 MeV. This new data product provides additional utility to the ECT data and offers a consistent cross calibrated data set for researchers interested in examining the dynamics of the inner magnetosphere across a wide range of energies.

3.
Science ; 341(6149): 991-4, 2013 Aug 30.
Artículo en Inglés | MEDLINE | ID: mdl-23887876

RESUMEN

The Van Allen radiation belts contain ultrarelativistic electrons trapped in Earth's magnetic field. Since their discovery in 1958, a fundamental unanswered question has been how electrons can be accelerated to such high energies. Two classes of processes have been proposed: transport and acceleration of electrons from a source population located outside the radiation belts (radial acceleration) or acceleration of lower-energy electrons to relativistic energies in situ in the heart of the radiation belts (local acceleration). We report measurements from NASA's Van Allen Radiation Belt Storm Probes that clearly distinguish between the two types of acceleration. The observed radial profiles of phase space density are characteristic of local acceleration in the heart of the radiation belts and are inconsistent with a predominantly radial acceleration process.

4.
Nanotechnology ; 19(26): 265102, 2008 Jul 02.
Artículo en Inglés | MEDLINE | ID: mdl-21828671

RESUMEN

A method for synthesizing superparamagnetic iron oxide (SPIO) multi-nanoparticle aggregates as molecular magnetic resonance imaging (MRI) contrast agents is described. The approach utilizes organic acid/base interactions in the colloid to induce highly controllable nanoparticle aggregation. Monodisperse aggregates with diameters as large as 100 nm are synthesized by manipulating the interfacial surface chemistry of the SPIO nanoparticles in tetrahydrofuran solvent. Subsequent phospholipid micelle encapsulation yields micellar multi-SPIO (mmSPIO) aggregates with enhanced T(2) relaxivity (368.0 s(-1) mmol(-1) Fe) as compared to micellar single particle SPIO (302.0 s(-1) mmol(-1) Fe). mmSPIO conjugated to anti-CA125 monoclonal antibodies were incubated with ovarian carcinoma cell lines to demonstrate targeted in vitro molecular MRI, resulting in a 66% shortening in T(2) time for CA125 positive NIH:OVCAR-3 cells and a less than 3% change in T(2) time for CA125 negative SK-OV-3 cells. The controllable aggregation of mmSPIO shows potential for the development of molecular MRI contrast agents with optimal sizes for specific diagnostic imaging applications.

5.
Tidsskr Nor Laegeforen ; 117(30): 4375-9, 1997 Dec 10.
Artículo en Noruego | MEDLINE | ID: mdl-9456582

RESUMEN

Companion dogs are widespread in western countries, and scientific studies have proved that dogs have a number of positive effects on human health and well-being. Studies have shown reduced systolic blood pressure in dog owners compared to non-owners, as well as lowered concentrations of plasma triglycerides and cholesterol. Studies have also shown improved survival rates following myocardial infarction in dog owners compared to non-owners. Companion dogs are used systematically in "animal assisted therapy" in various institutions and hospitals, both as specific treatment of a medical condition and to improve well-being in certain groups of patients. The reasons for the positive effects of dogs on human health are not clearly identified. The attachment between people and their pets ("the human-animal bond") seems to have important physiological and psychological effects. Companion dogs have been shown to increase physical activity and social contact, which may also influence human health.


Asunto(s)
Animales Domésticos , Perros , Estado de Salud , Vínculo Humano-Animal , Animales , Humanos
6.
Tidsskr Nor Laegeforen ; 114(12): 1442-4, 1994 May 10.
Artículo en Noruego | MEDLINE | ID: mdl-8079235

RESUMEN

The aim of the study was to analyse general practitioners' decisions when certifying patients as sick. The study was conducted among 38 general practitioners in Bergen, Norway, during two weeks in March 1990. The need for certification of sickness was considered for 328 patients. Among these 91% were certified as sick and 9% were not found to be incapable of work. If the patients took the first initiative for certification, 95% received a certificate, while 84% were certified sick when the doctors took the first initiative (p < 0.001). When no objective signs, symptoms or findings were registered by the general practitioners, the patients took the first initiative for sickness certification in 85% and the doctor in 15% (p = 0.001) of the cases. The study indicates that the patients are a stronger controlling element than the general practitioners in the process of certification of sickness.


Asunto(s)
Absentismo , Seguro de Salud , Rol del Médico , Médicos de Familia , Actitud del Personal de Salud , Toma de Decisiones , Humanos , Seguro de Salud/estadística & datos numéricos , Noruega , Médicos de Familia/psicología , Encuestas y Cuestionarios
7.
Atherosclerosis ; 99(1): 79-86, 1993 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-8461063

RESUMEN

The aim was to examine the effect of testosterone on atherogenesis in cholesterol-fed, castrated male rabbits not mediated via different plasma cholesterol levels. The rabbits in the testosterone group (n = 19) and in the placebo group (n = 17) were injected intramuscularly twice weekly for 17 weeks with 25 mg testosterone enantate and placebo, respectively, reaching plasma testosterone levels of 50-150 nmol/l in the testosterone group. No effect of testosterone on liver function or body weight was detected, but at week 15 mean blood pressure was 75 +/- 2 mmHg (mean +/- S.E.) in the testosterone group compared with 69 +/- 2 mmHg in the placebo group (P < 0.05). To reduce variation in plasma cholesterol between the two groups, the amount of cholesterol fed to each rabbit was adjusted on the basis of weekly determinations of plasma cholesterol; the mean plasma cholesterol levels during the 17 weeks were 20.9 +/- 1.0 and 20.4 +/- 0.9 mmol/l for the placebo and testosterone groups. In the intima-inner medias of the aortic arch, the thoracic and the abdominal aorta there were no consistent significant differences in aortic cholesterol content, expressed either as nmol/cm2 or nmol/mg protein, between the two groups. However, the aortic cholesterol content tended to be lower in the testosterone group than in the placebo group. These findings suggest that in cholesterol-fed, castrated male rabbits, testosterone does not promote atherogenesis by an effect directly on the arterial wall.


Asunto(s)
Aorta/metabolismo , Arteriosclerosis/metabolismo , Colesterol en la Dieta/administración & dosificación , Colesterol/sangre , Testosterona/farmacología , Animales , Arteriosclerosis/fisiopatología , Presión Sanguínea/efectos de los fármacos , Peso Corporal , Colesterol/metabolismo , Pruebas de Función Hepática , Masculino , Conejos , Testosterona/sangre
9.
J Rheumatol ; 16(4): 455-8, 1989 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-2746584

RESUMEN

In a study of HLA-DR phenotypes in patients with rheumatoid arthritis (RA) and controls from the Saskatoon area and in Newfoundland, we found that certain phenotypes occurred more frequently in the patients than in healthy controls in both populations ("increased risk phenotypes"). The reverse was also true: certain phenotypes were reduced or excluded from patients with RA compared with controls. Three increased risk phenotypes with twice the expected frequencies or more were HLA-DR1,DR4; DR4 and DR4,DR5. Four "protective" phenotypes with half or less the expected frequencies were HLA-DR1, DR5; DR2; DR2,DR3 and DR3,DR7. We speculate that at least for the DR3,DR7 phenotype, the protective effect may be due to a hybrid DQw2 molecule.


Asunto(s)
Artritis Reumatoide/inmunología , Antígenos HLA-DR/genética , Ligamiento Genético , Antígenos HLA-DR/inmunología , Prueba de Histocompatibilidad , Humanos , Fenotipo , Estadística como Asunto
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