| 1. |
- Acciari, V. A., et al.
(författare)
-
Radio Imaging of the Very-High-Energy gamma-Ray Emission Region in the Central Engine of a Radio Galaxy
- 2009
-
Ingår i: Science. - : American Association for the Advancement of Science (AAAS). - 0036-8075 .- 1095-9203. ; 325:5939, s. 444-448
-
Tidskriftsartikel (refereegranskat)abstract
- The accretion of matter onto a massive black hole is believed to feed the relativistic plasma jets found in many active galactic nuclei (AGN). Although some AGN accelerate particles to energies exceeding 10(12) electron volts and are bright sources of very-high-energy (VHE) gamma-ray emission, it is not yet known where the VHE emission originates. Here we report on radio and VHE observations of the radio galaxy Messier 87, revealing a period of extremely strong VHE gamma-ray flares accompanied by a strong increase of the radio flux from its nucleus. These results imply that charged particles are accelerated to very high energies in the immediate vicinity of the black hole.
|
|
| 2. |
- Coustenis, A., et al.
(författare)
-
TandEM : Titan and Enceladus mission
- 2009
-
Ingår i: Experimental astronomy. - : Springer Science and Business Media LLC. - 0922-6435 .- 1572-9508. ; 23:3, s. 893-946
-
Tidskriftsartikel (refereegranskat)abstract
- TandEM was proposed as an L-class (large) mission in response to ESA's Cosmic Vision 2015-2025 Call, and accepted for further studies, with the goal of exploring Titan and Enceladus. The mission concept is to perform in situ investigations of two worlds tied together by location and properties, whose remarkable natures have been partly revealed by the ongoing Cassini-Huygens mission. These bodies still hold mysteries requiring a complete exploration using a variety of vehicles and instruments. TandEM is an ambitious mission because its targets are two of the most exciting and challenging bodies in the Solar System. It is designed to build on but exceed the scientific and technological accomplishments of the Cassini-Huygens mission, exploring Titan and Enceladus in ways that are not currently possible (full close-up and in situ coverage over long periods of time). In the current mission architecture, TandEM proposes to deliver two medium-sized spacecraft to the Saturnian system. One spacecraft would be an orbiter with a large host of instruments which would perform several Enceladus flybys and deliver penetrators to its surface before going into a dedicated orbit around Titan alone, while the other spacecraft would carry the Titan in situ investigation components, i.e. a hot-air balloon (MontgolfiSre) and possibly several landing probes to be delivered through the atmosphere.
|
|
| 3. |
- Brauckhoff, M., et al.
(författare)
-
Limitations of intraoperative adrenal remnant volume measurement in patients undergoing subtotal adrenalectomy
- 2008
-
Ingår i: World Journal of Surgery. - : Springer Science and Business Media LLC. - 0364-2313 .- 1432-2323. ; 32:5, s. 863-872
-
Tidskriftsartikel (refereegranskat)abstract
- Background: Recent studies have shown that a minimum of approximately one-third of one normal adrenal gland is required for sufficient adrenocortical stress capacity. Correlation between intraoperative measurement, determination of remnant size by computed tomography (CT), and adrenocortical stress capacity has not been examined so far. Methods: Twenty-two patients with familial pheochromocytoma (n = 13), sporadic pheochromocytoma (n = 3), and adrenocortical tumors (n = 6) who underwent unilateral or bilateral subtotal adrenalectomy (STAE, 28 adrenal remnants) were prospectively studied. Patients were examined in a multi-slice CT to determine residual adrenal tissue and by ACTH test 4 days and 3 months postoperatively. Results: There was a slight significant correlation between intraoperative and CT calculated volumes (r = 0.77, p < 0.001). However, volumes assessed by CT were almost doubled compared with intraoperative determination (p < 0.001). Although recovery of adrenal function could be observed, no significant changes of remnant volumes could be detected within 3 months. In patients with familial pheochromocytoma, there was a significant correlation between residual adrenal volume and stimulated cortisol levels (P < 0.001). A distinct minimum of adrenal volume for intact adrenocortical stress capacity could not be exactly determined, however, in one patient with only 10% residual adrenal tissue intact stress capacity was found. Conclusions: Residual adrenal tissue of approximately 10-15% offers intact stress capacity. However, an exact determination of the size of an adrenal remnant after STAE has limitations. CT gives larger volumes compared with intraoperative determination. For calculation of a volume-function correlation of residual adrenal tissue, in clinical practice, the determination of relative adrenal residual volume is acceptable. © 2008 Société Internationale de Chirurgie.
|
|
| 4. |
- Lorenz, K, et al.
(författare)
-
Europium doping of zincblende GaN by ion implantation
- 2009
-
Ingår i: Journal of Applied Physics. - : AIP Publishing. - 0021-8979 .- 1089-7550. ; 105:11, s. 113507-
-
Tidskriftsartikel (refereegranskat)abstract
- Eu was implanted into high quality cubic (zincblende) GaN (ZB-GaN) layers grown by molecular beam epitaxy. Detailed structural characterization before and after implantation was performed by x-ray diffraction (XRD) and Rutherford backscattering/channeling spectrometry. A low concentration (<10%) of wurtzite phase inclusions was observed by XRD analysis in as-grown samples with their (0001) planes aligned with the {111} planes of the cubic lattice. Implantation of Eu causes an expansion of the lattice parameter in the implanted region similar to that observed for the c-lattice parameter of wurtzite GaN (W-GaN). For ZB-GaN:Eu, a large fraction of Eu ions is found on a high symmetry interstitial site aligned with the 〈110〉 direction, while a Ga substitutional site is observed for W-GaN:Eu. The implantation damage in ZB-GaN:Eu could partly be removed by thermal annealing, but an increase in the wurtzite phase fraction was observed at the same time. Cathodoluminescence, photoluminescence (PL), and PL excitation spectroscopy revealed several emission lines which can be attributed to distinct Eu-related optical centers in ZB-GaN and W-GaN inclusions.
|
|
| 5. |
- Bogolepova, O.K., et al.
(författare)
-
The Neoproterozoic - Palaeozoic Sedimentary Basin of Severnaya Zemlya
- 2006
-
Ingår i: 'The History of Convergent and Passive Margins in the Polar Realm: Sedimentary and Tectonic Processes, Transitions and Resources', International Lithosphere Program Task Force on Sedimentary Basins, Quebec, Canada.
-
Konferensbidrag (populärvet., debatt m.m.)
|
|
| 6. |
- Darakchieva, Vanya, et al.
(författare)
-
Role of impurities and dislocations for the unintentional n-type conductivity in InN
- 2009
-
Ingår i: PHYSICA B-CONDENSED MATTER. - : Elsevier BV. - 0921-4526. ; 404:22, s. 4476-4481
-
Tidskriftsartikel (refereegranskat)abstract
- We present a study on the role of dislocations and impurities for the unintentional n-type conductivity in high-quality InN grown by molecular beam epitaxy. The dislocation densities and H profiles in films with free electron concentrations in the low 10(17) cm(-1) and mid 10(18) cm(-3) range are measured, and analyzed in a comparative manner. It is shown that dislocations alone could not account for the free electron behavior in the InN films. On the other hand, large concentrations of H sufficient to explain, but exceeding substantially, the observed free electron densities are found. Furthermore, enhanced concentrations of H are revealed at the film surfaces, resembling the free electron behavior with surface electron accumulation. The low-conductive film was found to contain C and it is suggested that C passivates the H donors or acts as an acceptor, producing compensated material in this case. Therefore, it is concluded that the unintentional impurities play an important role for the unintentional n-type conductivity in InN. We suggest a scenario of H incorporation in InN that may reconcile the previously reported observations for the different role of impurities and dislocations for the unintentional n-type conductivity in InN.
|
|
| 7. |
- Gee, D.G., et al.
(författare)
-
A New Tectonic Map of the Arctic at 1:10 M
- 2006
-
Ingår i: 'The History of Convergent and Passive Margins in the Polar Realm: Sedimentary and Tectonic Processes, Transitions and Resources'.
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)
|
|
| 8. |
- Gimm, O, et al.
(författare)
-
[Prophylactic parathyroidectomy for familial parathyroid carcinoma].
- 2006
-
Ingår i: Der Chirurg. - : Springer Science and Business Media LLC. - 0009-4722 .- 1433-0385. ; 77:1, s. 15-24
-
Tidskriftsartikel (refereegranskat)abstract
- In contrast to primary hyperparathyroidism, parathyroid carcinoma is a rare disease. In patients with hyperparathyroidism jaw tumor (HPT-JT) syndrome, caused by germline mutations in HRPT2, the development of parathyroid carcinoma is estimated to be 10-15%. This review summarizes the clinical and molecular genetic data of about 100 patients in the literature and three of our own cases. Unfortunately, osteofibromas, which might enable timely diagnosis of HPT-JT syndrome, occur in only about 30% of patients; about 80% have uniglandular disease. Based on the current data, a general recommendation to perform prophylactic parathyroidectomy cannot be given. However, thorough screening of patients at risk is mandatory. Of note in patients thought to have sporadic parathyroid carcinoma, germline HRPT2 mutations are found in up to 20%. Hence, any patient with parathyroid carcinoma should undergo HRPT2 mutation analysis.
|
|
| 9. |
- Hernandez, A. F., et al.
(författare)
-
Rationale and design of the Acute Study of Clinical Effectiveness of Nesiritide in Decompensated Heart Failure Trial (ASCEND-HF)
- 2009
-
Ingår i: Am Heart J. - 1097-6744. ; 157:2, s. 271-7
-
Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Acute decompensated heart failure (ADHF) is a major public health burden with significant mortality and morbidity. Nesiritide is a recombinantly produced intravenous formulation of human B-type natriuretic peptide that promotes vasodilation and increases salt and water excretion, which results in reduced cardiac filling pressures. Prior studies have shown that dyspnea is improved in patients with ADHF 3 hours after nesiritide infusion with significant dose-related reductions in cardiac filling pressures and systemic vascular resistance without significant arrhythmias. However, the effect of nesiritide on dyspnea at 6 or 24 hours is unknown, and no clinical outcome trials have been done to provide a reliable estimate of the effect of nesiritide on morbidity and mortality. METHODS: The Acute Study of Clinical Effectiveness of Nesiritide in Decompensated Heart Failure trial (ASCEND-HF) is a phase III study evaluating the efficacy and safety of nesiritide in patients with ADHF. Patients hospitalized for hear failure will be randomly assigned to receive either intravenous nesiritide or matching placebo for 24 hours to 7 days. The 2 coprimary end points are (1) assessment of acute dyspnea at 6 or 24 hours and (2) death or rehospitalization for hear failure within 30 days. A total of 7,000 patients will be enrolled worldwide between 2007 and 2010. CONCLUSIONS: The data from the ASCEND-HF trial will establish whether nesiritide safely improves acute dyspnea as well as morbidity and mortality at 30 days.
|
|
| 10. |
|
|
