967 resultados para cosmic background radiation
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Background: CMR has recently emerged as a robust and reliable technique to assess coronary artery disease (CAD). A negative perfusion CMR test predicts low event rates of 0.3-0.5%/year. Invasive coronary angiography (CA) remains the "gold standard" for the evaluation of CAD in many countries.Objective: Assessing the costs of the two strategies in the European CMR registry for the work-up of known or suspected CAD from a health care payer perspective. Strategy 1) a CA to all patients or 2) a CA only to patients who are diagnosed positive for ischemia in a prior CMR.Method and results: Using data of the European CMR registry (20 hospitals, 11'040 consecutive patients) we calculated the proportion of patients who were diagnosed positive (20.6%), uncertain (6.5%), and negative (72.9%) after the CMR test in patients with known or suspected CAD (n=2'717). No other medical test was performed to patients who were negative for ischemia. Positive diagnosed patients had a coronary angiography. Those with uncertain diagnosis had additional tests (84.7%: stress echocardiography, 13.1%: CCT, 2.3% SPECT), these costs were added to the CMR strategy costs. Information from costs for tests in Germany and Switzerland were used. A sensibility analysis was performed for inpatient CA. For costs see figure. Results - costs.Discussion: The CMR strategy costs less than the CA strategy for the health insurance systems both, in Germany and Switzerland. While lower in costs, the CMR strategy is a non-invasive one, does not expose to radiation, and yields additional information on cardiac function, viability, valves, and great vessels. Developing the use of CMR instead of CA might imply some reduction in costs together with superior patient safety and comfort, and a better utilization of resources at the hospital level. Document introduit le : 01.12.2011
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El nostre objectiu es l'estudi d'extensions de la Relativitat General i, en particular, estem interessats en les teories que continguin camps vectorials addicionals. En aquests tipus de teories es necessari imposar que el vector ha de tenir norma fixa per evitar la presència d'un fantasma o grau de llibertat amb terme cinètic negatiu, i això implica que la simetria Lorentz està trencada espontàniament. El camp del aether només interactua gravitatòriament i la seva presència es difícil de detectar, no obstant això, durant inflació les fluctuacions del buit a escales petites d'un camp lleuger pot deixar una empremta en observables com les anisotropies del fons de radiació de microones. Les fluctuacions del Einstein-aether es comporten com els camps sense massa i això fa que inflació generi modes de longitud de ona llarga en els sectors escalar i vectorial. Hem estudiat la signatura del Einstein-aether dins l'espectre de pertorbacions primordials lluny del límit de de Sitter de inflació. Aquests modes escalars i vectorials poden deixar una empremta significativa en la radiació de fons de microones en funció dels paràmetres del model. Les observacions del fons de radiació de microones imposen restriccions fenomenològiques que redueixen els límits existents per aquesta classe de teoria. Amb aquest estudi del aether també esperem millorar el coneixement que tenim de una classe més ampla de teories que exhibeixen el mateix tipus de trencament de simetria.
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A population of 420 snails Biomphalaria straminea, an intermediate host of Schistosoma mansoni, received gamma-rays obtained from a 60Co source in low-doses (0/2,5/5/7,5/10/15/20 and 25 Gy); half population was kept in colonies (allowing cross fertilization) and the other half was mantained in sexual isolation (allowing self fertilization). Results showed that 15 Gy stimulates the fertility of both groups but the colonies were more sensitive and at this dose its fertility overpasses the control group dose. The possible hormonal role played in the observed phenomena is under investigation
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PURPOSE: Temozolomide is a novel oral alkylating agent with demonstrated efficacy as second-line therapy for patients with recurrent anaplastic astrocytoma and glioblastoma multiforme (GBM). This phase II study was performed to determine the safety, tolerability, and efficacy of concomitant radiation plus temozolomide therapy followed by adjuvant temozolomide therapy in patients with newly diagnosed GBM. PATIENTS AND METHODS: Sixty-four patients were enrolled onto this open-label, phase II trial. Temozolomide (75 mg/m(2)/d x 7 d/wk for 6 weeks) was administered orally concomitant with fractionated radiotherapy (60 Gy total dose: 2 Gy x 5 d/wk for 6 weeks) followed by temozolomide monotherapy (200 mg/m(2)/d x 5 days, every 28 days for six cycles). The primary end points were safety and tolerability, and the secondary end point was overall survival. RESULTS: Concomitant radiation plus temozolomide therapy was safe and well tolerated. Nonhematologic toxicities were rare and mild to moderate in severity. During the concomitant treatment phase, grade 3 or 4 neutropenia, thrombocytopenia, or both were observed in 6% of patients, including two severe infections with Pneumocystis carinii. During adjuvant temozolomide, 2% and 6% of cycles were associated with grade 3 and 4 neutropenia or thrombocytopenia, respectively. Median survival was 16 months, and the 1- and 2-year survival rates were 58% and 31%, respectively. Patients younger than 50 years old and patients who underwent debulking surgery had the best survival outcome. CONCLUSION: Continuous daily temozolomide and concomitant radiation is safe. This regimen of concomitant chemoradiotherapy followed by adjuvant chemotherapy may prolong the survival of patients with glioblastoma. Further investigation is warranted, and a randomized trial is ongoing.
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Doses of 60Co gamma radiation with 2.5; 5; 7.5; 10; 15; 20; 25; 30; 35; 40; 45; 50; 55; 60; 80; 160; 320 and 640 Gy were applied to 1,080 snails Biomphalaria straminea, an intermediate host of Schistosoma mansoni, divided in groups containing 30 mollusks. In addition, 60 non irradiated snails were kept as control. Fifty percent of the population was kept in colonies (allowing cross fertilization) while the other half was maintained in sexual isolation (allowing self fertilization) and during one month their growth was observed through the daily measurement of the shell diameter. Results showed that after 20 Gy doses the growth in shell diameter of irradiated snails was greater than that of the control group after 30 days. At this dose the snail size was the greatest, among all isolated groups. The 80 Gy doses also induced the final shell diameter of isolated snails to be greater then that observed in the control groups. As this effect was most evident among the isolated snails, a possible hormonal role may have been involved in the observed phenomena, which is under investigation with the objective of identifying any future applications that this could have to schistosomiasis control.
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OBJECTIVES: To evaluate the long-term disease-free and overall survival of patients with sentinel lymph node (SLN) micrometastases, in whom a completion axillary lymph node dissection (ALND) was systematically omitted. BACKGROUND: The use of step sectioning and immunohistochemistry for SLN analysis results in a more accurate histopathologic examination and a higher detection rate of micrometastases. However, the clinical relevance and therapeutic implications of SLN micrometastases remain a matter of debate. METHODS: In this prospective study, 236 SLN biopsies were performed in 234 consecutive early-stage breast cancer patients (T1, T2 </= 3 cm, cN0 M0) between 1998 and 2002. The SLN were examined by step sectioning and stained with hematoxylin and eosin and immunohistochemistry. None of the patients with negative SLN or SLN micrometastases (International Union Against Cancer classification, >.2 mm to </=2 mm) underwent a completion ALND or radiation to the axilla. Long-term overall and disease-free survivals were compared between patients with negative SLN and those with SLN micrometastases by log rank tests. RESULTS: The SLN was negative in 55% of patients (123 of 224). SLN micrometastases were detected in 27 patients (27 of 224, 12%). After a median follow-up of 77 months (range, 24-106 months), neither locoregional recurrences nor distant metastases occurred in any of the 27 patients with SLN micrometastases. There were no statistically significant differences for overall (P = .656), locoregional (P = .174), and axillary and distant disease-free survival (P = .15) between patients with negative SLN and SLN micrometastases. CONCLUSIONS: This analysis of unselected patients provides evidence that a completion level I and II ALND may be safely omitted in early-stage breast cancer patients with SLN micrometastases.
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The Presence of highly pathogenicH5N1 avian influenza has been confirmed in birds in Turkey, Romania, Russia and Kazakhstan. There have been a total of 4 confirmed cases of human infection in Eastern/South Eastern Turkey that has resulted in 2 deaths. Background Avian influenza naturally circulates in wild waterfowl such as ducks and geese often causing little or no symptoms. Many other bird species are susceptible to infection with these influenza viruses and in many of these species it may cause severe disease associated with high mortality. Outbreaks associated with high bird mortality are called Highly Pathogenic Avian Influenza (HPAI) to distinguish them from less pathogenic influenza. In January 2004 avian influenza in poultry was confirmed in Vietnam. Subsequently, there have been very substantial outbreaks of avian influenza associated with high mortality affecting poultry in various countries throughout Asia including Vietnam, Thailand, China, Malaysia, Mongolia, North & South Korea, Cambodia, Indonesia, Laos and Japan. These outbreaks are caused by H5N1 subtype of influenza A virus, the same subtype (but not identical to the virus) that caused the outbreak in Hong Kong in 1997. åÊ
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BackgroundThe importance of hybridisation during species diversification has long been debated among evolutionary biologists. It is increasingly recognised that hybridisation events occurred during the evolutionary history of numerous species, especially during the early stages of adaptive radiation. We study the effect of hybridisation on diversification in the clownfishes, a clade of coral reef fish that diversified through an adaptive radiation process. While two species of clownfish are likely to have been described from hybrid specimens, the occurrence and effect of hybridisation on the clade diversification is yet unknown.ResultsWe generate sequences of three mitochondrial genes to complete an existing dataset of nuclear sequences and document cytonuclear discordance at a node, which shows a drastic increase of diversification rate. Then, using a tree-based jack-knife method, we identify clownfish species likely stemming from hybridisation events. Finally, we use molecular cloning and identify the putative parental species of four clownfish specimens that display the morphological characteristics of hybrids.ConclusionsOur results show that consistently with the syngameon hypothesis, hybridisation events are linked with a burst of diversification in the clownfishes. Moreover, several recently diverged clownfish lineages likely originated through hybridisation, which indicates that diversification, catalysed by hybridisation events, may still be happening.
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OBJECTIVE: Quality assurance (QA) in clinical trials is essential to ensure treatment is safely and effectively delivered. As QA requirements have increased in complexity in parallel with evolution of radiation therapy (RT) delivery, a need to facilitate digital data exchange emerged. Our objective is to present the platform developed for the integration and standardization of QART activities across all EORTC trials involving RT. METHODS: The following essential requirements were identified: secure and easy access without on-site software installation; integration within the existing EORTC clinical remote data capture system; and the ability to both customize the platform to specific studies and adapt to future needs. After retrospective testing within several clinical trials, the platform was introduced in phases to participating sites and QART study reviewers. RESULTS: The resulting QA platform, integrating RT analysis software installed at EORTC Headquarters, permits timely, secure, and fully digital central DICOM-RT based data review. Participating sites submit data through a standard secure upload webpage. Supplemental information is submitted in parallel through web-based forms. An internal quality check by the QART office verifies data consistency, formatting, and anonymization. QART reviewers have remote access through a terminal server. Reviewers evaluate submissions for protocol compliance through an online evaluation matrix. Comments are collected by the coordinating centre and institutions are informed of the results. CONCLUSIONS: This web-based central review platform facilitates rapid, extensive, and prospective QART review. This reduces the risk that trial outcomes are compromised through inadequate radiotherapy and facilitates correlation of results with clinical outcomes.
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Surgery has historically been the standard of care for operable stage I non-small cell lung cancer (NSCLC). However, nearly one-quarter of patients with stage I NSCLC will not undergo surgery because of medical comorbidity or other factors. Stereotactic ablative radiotherapy (SABR) is the new standard of care for these patients. SABR offers high local tumour control rates rivalling the historical results of surgery and is generally well tolerated by patients with both peripheral and centrally located tumours. This article reviews the history of SABR for stage I NSCLC, summarises the currently available data on efficacy and toxicity, and describes some of the currently controversial aspects of this treatment.
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The Development of Radiation Oncology Services in Ireland The provision of a high quality radiation oncology service is one of the cornerstones of a modern treatment programme for cancer patients. Timely and equitable access to a radiation oncology service of the highest international standard should be available to all cancer patients in Ireland and it was the achievement of this goal that guided and motivated the group in producing this report and its accompanying recommendations. Click here to download PDF 46kb
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