69,679 research outputs found
Nucleosynthesis in Advective Accretion Disks Around Galactic and Extra-Galactic Black Holes
We compute the nucleosynthesis of materials inside advective disks around
black holes. We show that composition of incoming matter can change
significantly depending on the accretion rate and accretion disks. These works
are improvements on the earlier works in thick accretion disks of Chakrabarti,
Jin & Arnett (1987) in presence of advection in the flow.Comment: Latex pages including figures. Kluwer Style files included. Appearing
in `Observational Evidence for Black Holes in the Universe', ed. Sandip K.
Chakrabarti, Kluwer Academic Publishers (DORDRECHT: Holland
Accretion Disks Around Black Holes: Twenty Five Years Later
We study the progress of the theory of accretion disks around black holes in
last twenty five years and explain why advective disks are the best bet in
explaining varied stationary and non-stationary observations from black hole
candidates. We show also that the recently proposed advection dominated flows
are incorrect.Comment: 30 Latex pages including figures. Kluwer Style files included.
Appearing in `Observational Evidence for Black Holes in the Universe', ed.
Sandip K. Chakrabarti, Kluwer Academic Publishers (DORDRECHT: Holland
The Landscape of Realized Homologous Recombination in Pathogenic Bacteria
Recombination enhances the adaptive potential of organisms by allowing genetic variants to be tested on multiple genomic backgrounds. Its distribution in the genome can provide insight into the evolutionary forces that underlie traits, such as the emergence of pathogenicity. Here, we examined landscapes of realized homologous recombination of 500 genomes from ten bacterial species and found all species have “hot” regions with elevated rates relative to the genome average. We examined the size, gene content, and chromosomal features associated with these regions and the correlations between closely related species. The recombination landscape is variable and evolves rapidly. For example in Salmonella, only short regions of around 1 kb in length are hot whereas in the closely related species Escherichia coli, some hot regions exceed 100 kb, spanning many genes. Only Streptococcus pyogenes shows evidence for the positive correlation between GC content and recombination that has been reported for several eukaryotes. Genes with function related to the cell surface/membrane are often found in recombination hot regions but E. coli is the only species where genes annotated as “virulence associated” are consistently hotter. There is also evidence that some genes with “housekeeping” functions tend to be overrepresented in cold regions. For example, ribosomal proteins showed low recombination in all of the species. Among specific genes, transferrin-binding proteins are recombination hot in all three of the species in which they were found, and are subject to interspecies recombination
Beating heart coronary surgery and renal function: a prospective randomised study (Presented at 18th Spring Meeting of the Association of Cardiothoracic Anaesthetists: Selected abstracts, Cambridge, UK. 22 June 2001)
Introduction
Cardiopulmonary bypass (CPB) is widely regarded as an important contributor to renal failure, a well recognised complication, following coronary artery surgery (CABG). Off-pump coronary surgery (OPCAB) is intuitively considered renoprotective. We examine the extent of renal glomerular and tubular injury in low-risk patients undergoing either OPCAB or on-pump coronary artery bypass (ONCAB).Methods
Forty patients awaiting elective CABG were prospectively randomized into those undergoing OPCAB (n = 20) and ONCAB (n = 20). Table 1 illustrates the exclusion criteria. Glomerular and tubular injury were assessed, respectively, by urinary excretion of microalbumin and retinol binding protein (RBP) indexed to urinary creatinine [1]. Daily measurements were made from admission to postoperative day 5. Fluid balance, serum creati-nine and blood urea were also monitored.
Results
No mortality or renal complication was observed. Both groups had similar demographic make-up. The OPCAB group received fewer coronary grafts than their counterparts (1.8 versus 2.8; P = 0.002). Serum creatinine and blood urea remained normal in both groups throughout the study. A dramatic and similar rise in mean ± 2SD urinary RBP:creatinine ratio occurred in both groups peaking on day 1 (3183 ± 2534 versus 4035 ± 4078; P = 0.43) before returning to baseline levels. These trends were also observed with the urinary microalbumin:creatinine ratio (5.05 ± 2.66 versus 6.77 ± 5.76; P = 0.22). ONCAB patients had a significantly more negative fluid balance on postoperative day 2 (-183 ± 1118 versus 637 ± 847 ml; P < 0.05).
Conclusions
Although renal dysfunction did not clinically occur in any patient, sensitive indicators revealed significant and similar injury to both renal tubules and glomeruli following either OPCAB or ONCAB. These suggest that avoidance of CPB per se does not offer additional renoprotection to patients at low risk of perioperative renal insult during CABG
An animal experimental study on pubourethral ligament restoration with platelet rich plasma for the treatment of stress urinary incontinence.
Introduction: Minimally invasive methods for injured ligament and tendon restoration have been developed and gained popularity in recent years. Injury and relaxation of the pubourethral ligament (PUL) can lead to stress urinary incontinence (SUI). The aim of this study was to investigate the impact of injecting platelet rich plasma (PRP) into the PUL following its surgical transection resulting in SUI, confirmed by leak point pressure (LPP) measurements pre- and post-intervention in an experimental animal model. Material and methods: Twenty female adult Sprague-Dawley rats were assigned in 2 groups: 1) treatment group with transection of the PUL and application of PRP at the time of transection and at one month follow-up and 2) a control group, with transection of the PUL only. Leak point pressures (LPPs) were measured prior to transection, immediately following the transection and at 1 and 2 months in both groups. Results: The median LPPs for the control group were: LPP - preT: 35.6 (29.8-44.8) cmH2O, LPP - postT: 14.6 (5.8-19.0) cmH2O, LPP - 1 month: 27.3 (19.2-33.8) cmH2O, LPP - 2 months: 29.0 (27.0-34.0) cmH2O, whereas for the PRP group were: LPP-preT: 40.5 (33.2-46.3) cmH2O, LPP - postT: 15.7 (3.0-24.0) cmH2O, LPP - 1month: 31.6 (24.8-37.4) cmH2O, LPP - 2 months: 36.8 (32.5-45.4) cmH2O. PRP injections on transected PULs significantly increased LPPs at one month follow-up [31.6 cmH2O vs. 27.3 cmH2O, p = .043]. This effect was confirmed at two months [36.8 cmH2O vs. 29.0 cmH2O, p <.001]. Conclusions: Injection of PRP into transected PULs significantly improved LPPs at one and two months' follow-up. However, further experimental and clinical research is needed to evaluate the safety and efficacy of this treatment, in clinical practice
Adoption of cloud computing in outsourcing: A new model
© 2012 IADIS. The authors have discussed the evolution of computer manufacturing industry from the traditional model to the current lean and just-in-time manufacturing model. Information technology is outsourced to reduce cost. The outsourcing model evolution is influenced by technology changes. The paper gives an overview of cloud computing, the current outsourcing model and relates the transformation of computer manufacturing to transformation of the emerging outsourcing model due to cloud computing. The proposed outsourcing model based on cloud computing is discussed
Comparing Computing Platforms for Deep Learning on a Humanoid Robot
The goal of this study is to test two different computing platforms with
respect to their suitability for running deep networks as part of a humanoid
robot software system. One of the platforms is the CPU-centered Intel NUC7i7BNH
and the other is a NVIDIA Jetson TX2 system that puts more emphasis on GPU
processing. The experiments addressed a number of benchmarking tasks including
pedestrian detection using deep neural networks. Some of the results were
unexpected but demonstrate that platforms exhibit both advantages and
disadvantages when taking computational performance and electrical power
requirements of such a system into account.Comment: 12 pages, 5 figure
Biodiversity of few Indian charophyte taxa based on molecular characterization and construction of phylogenetic tree
The world charophyte flora suffered reshuffling in the taxonomic status of many taxa on the basis of certain morphological characters. Large numbers of species were reduced to the status of subspecies, variety or forma while some distant species were merged together. In this study, molecular characteristics such as band frequency, RAPD polymorphism, genetic identity index or similarity index, band sharing frequency and genetic distance within and in between Chara and Nitella were evaluated. With the help of scorable bands, range of molecular sizes was recorded in amplified products of 12charophyte taxa by using five random primers. This investigation requires further elaboration to reach a definite conclusio
- …