Modellierung der unter- und oberseitigen Wärmeübertragung an plattenförmiges Gut in Rollenöfen

Roller kiln, radiant tube, roller, heat trensfer, analytical solution, FEM

Hybridisation and diversification in the adaptive radiation of clownfishes.

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.

Cardiopulmonary support and extracorporeal membrane oxygenation for cardiac assist.

BACKGROUND: Use of cardiopulmonary bypass for emergency resuscitation is not new. In fact, John Gibbon proposed this concept for the treatment of severe pulmonary embolism in 1937. Significant progress has been made since, and two main concepts for cardiac assist based on cardiopulmonary bypass have emerged: cardiopulmonary support (CPS) and extracorporeal membrane oxygenation (ECMO). The objective of this review is to summarize the state of the art in these two technologies. METHODS: Configuration of CPS is now fairly standard. A mobile cart with relatively large wheels allowing for easy transportation carries a centrifugal pump, a back-up battery with a charger, an oxygen cylinder, and a small heating system. Percutaneous cannulation, pump-driven venous return, rapid availability, and transportability are the main characteristics of a CPS system. Cardiocirculatory arrest is a major predictor of mortality despite the use of CPS. In contrast, CPS appears to be a powerful tool for patients in cardiogenic shock before cardiocirculatory arrest, requiring some type of therapeutic procedures, especially repair of anatomically correctable problems or bridging to other mechanical circulatory support systems such as ventricular assist devices. CPS is in general not suitable for long-term applications because of the small-bore cannulas, resulting in significant pressure gradients and eventually hemolysis. RESULTS: In contrast, ECMO can be designed for longer-term circulatory support. This requires large-bore cannulas and specifically designed oxygenators. The latter are either plasma leakage resistent (true membranes) or relatively thrombo-resistant (heparin coated). Both technologies require oxygenator changeovers although the main reason for this is different (clotting for the former, plasma leakage for the latter). Likewise, the tubing within a roller pump has to be displaced and centrifugal pump heads have to be replaced over time. ECMO is certainly the first choice for a circulatory support system in the neonatal and pediatric age groups, where the other assist systems are too bulky. ECMO is also indicated for patients improving on CPS. Septic conditions are, in general, considered as contraindications for ECMO. CONCLUSIONS: Ease of availability and moderate cost of cardiopulmonary bypass-based cardiac support technologies have to be balanced against the significant immobilization of human resources, which is required to make them successful.

Burnt outside raw in the middle

Sometimes it's hard to tell when burgers and sausages are properly cooked and ready to eat. These meats can contain harmful bacteria throughout and it is important that they are cooked thoroughly to make them safe to eat. To check that a burger or sausage is properly cooked, cut into the middle with a clean knife and check that it is piping hot all the way through, there is no pink meat left and the juices run clear.

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Research on individual social policy preferences has highlighted a number of socio-structural cleavages as determinants. Studies investigating public opinion on the various redistributive schemes that make up today's welfare states have shown the relevance of class-related factors such as income or education as key explanatory variables (Ferrera 1993; Taylor-Gooby 1995, 1998; and Svallfors 1997). More recent studies, however, have suggested that other factors are also likely to play a role. Among these, the most important are age, gender, and individual values (Armingeon 2006; Deitch 2004; and Roller 2000, 2002). The scenario that emerges from the existing literature is one of multiple intersecting cleavages, but it remains unclear as to what today is the relative weight and specific impact of each of these cleavages.

Cutting artefacts and cutting process in vitreous sections for cryo-electron microscopy.

Cryo-electron microscopy of vitreous sections (CEMOVIS) has recently been shown to provide images of biological specimens with unprecedented quality and resolution. Cutting the sections remains however the major difficulty. Here, we examine the parameters influencing the quality of the sections and analyse the resulting artefacts. They are in particular: knife marks, compression, crevasses, and chatter. We propose a model taking into account the interplay between viscous flow and fracture. We confirm that crevasses are formed on only one side of the section, and define conditions by which they can be avoided. Chatter is an effect of irregular compression due to friction of the section of the knife edge and conditions to prevent this are also explored. In absence of crevasses and chatter, the bulk of the section is compressed approximately homogeneously. Within this approximation, it is possible to correct for compression by a simple linear transformation for the bulk of the section. A research program is proposed to test and refine our understanding of the sectioning process.

Duodenal duplication cyst and pancreas divisum causing acute pancreatitis in an adult male acute pancreatitis in an adult male

Duodenal duplication cysts are rare congenital abnormalities which are more commonly diagnosed in infancy and childhood. However, in rare cases, these lesions can remain asymptomatic until adulthood. The combination of duplication cyst and pancreas divisum is extremely rare and both conditions have been linked with acute recurrent pancreatitis. We present the case of a 37 years-old patient who presented with repeated episodes of acute pancreatitis. By means of magnetic resonance imaging and endoscopic ultrasonography we discovered a duplication cyst whose cavity received drainage from the dorsal pancreas. After opening the cyst cavity to the duodenal lumen with a needle knife the patient presented no further episodes in the clinical follow-up. Comparable literature findings and therapeutic options for these abnormalities are discussed with regard to the presented case.

MR-based follow-up of the superior cerebellar artery after radiosurgery for trigeminal neuralgia.

Purpose: To study with a non invasive method any potential radiological change on the superior cerebellar artery (SCA) in patients treated radiosurgically for classic trigeminal neuralgia (CTN).Materials and methods: A retrospective measure of maximal dose received by SCA was performed analyzing the treatment planning in 55 consecutive patients treated by Gamma Knife radiosurgery for an CTN, then, a prospective study was designed using high resolution MR, with T2 SPIR, T1 without and with gadolinium enhancement, Proton density, 3D TONE and MIP reconstructions. Inclusion criteria were: patients followed at our institution, follow-up of one year or more, dose received by the SCA of 15 Gy or more and voluntary patient participation in the study. Patients with repeated Gamma Knife radiosurgery for failure or recurrence were excluded. The end points were: SCA occlusion, stenosis or infarction in the territory supplied by SCA.Results: Sixteen patients were studied, with a mean follow-up of 25.2 months (12-42 months). The mean maximal dose received by the SCA was 57.5 Gy. (15-87 Gy). Among these 16 patients studied, neither obstruction of the SCA nor infarction was demonstrated. In one patient a suspicion of asymptomatic SCA stenosis was visualized distant to the irradiation field.Conclusions: SCA can receive a high dose of irradiation during radiosurgical treatment for CTN. This study does not confirm any vascular damage to the SCA after radiosurgery for CTN. (C) 2011 Elsevier B.V. All rights reserved.

Detection of fat embolism in cases with postmortem angiography (PMA) - Preliminary results

Introduction: Pulmonary fat embolism (PFE) can be a cause of death in cases with trauma, during orthopedic surgery and also in non-traumatic conditions, such as burns, pancreatitis, fatty liver or sickle cell disease. As PMA becomes more widespread, it is important to determine how it affects the diagnosis of PFE. Aims: The aim of this study was to determine if the oily contrast liquid used in PMA induces artefactual PFE, if such artefacts differ from original PFE and if PFE can be detected and graded before PMA. Material and methods: Cases of adults without signs of postmortem change and for which an autopsy with angiography was performed were selected for this study. Pulmonary biopsies of each lung were taken before and after the angiography as were fragments of each lung with a twin-edged knife during the autopsy. The samples were examined under the microscope without fixation or staining and after an Oil-Red O staining. PFE was graded according to Falci et al. Results: Non-artefactual (original) PFE was diagnosed in 4 cases on pre-PMA biopsies. As expected, structures with the aspect of PFE were present in all cases after angiography. The microscopical aspect of original and PMA induced PFE was identical. Grading of the PFE according to Falci et al. was depending on the quality of the biopsies. Conclusions: PMA with oily contrast induces artefactual PFE that cannot be visually differentiated from original PFE. Original PFE can however be diagnosed with pre-angiography biopsies. In order to assure the diagnosis and correct grading of PFE, the quality of the biopsy should be checked before PMA with oily contrast.

Trends in indices of daily precipitation extremes in Catalonia (NE Spain), 1951-2003

The aim of this paper is to quantitatively characterize the climatology of daily precipitation indices in Catalonia (northeastern Iberian Peninsula) from 1951 to 2003. This work has been performed analyzing a subset of the ETCCDI (Expert Team on Climate Change Detection and Indices) precipitation indices calculated from a new interpolated dataset of daily precipitation, namely SPAIN02, regular at 0.2° horizontal resolution (around 20 km) and from two high-quality stations: the Ebro and Fabra observatories. Using a jack-knife technique, we have found that the sampling error of the SPAIN02 regional averaged is relatively low. The trend analysis has been implemented using a Circular Block Bootstrap procedure applicable to non-normal distributions and autocorrelated series. A running trend analysis has been applied to analyze the trend persistence. No general trends at a regional scale are observed, considering the annual or the seasonal regional averaged series of all the indices for all the time windows considered. Only the consecutive dry days index (CDD) at annual scale shows a locally coherent spatial trend pattern; around 30% of the Catalonia area has experienced an increase of around 2¿3 days decade¿1. The Ebro and Fabra observatories show a similar CDD trend, mainly due to the summer contribution. Besides this, a significant decrease in total precipitation (around ¿10 mm decade¿1) and in the index "highest precipitation amount in five-day period" (RX5DAY, around ¿5 mm decade¿1), have been found in summer for the Ebro observatory.