1,197 research outputs found
Tactile cognition in rodents
Since the discovery 50 years ago of the precisely ordered representation of the whiskers in somatosensory cortex, the rodent tactile sensory system has been a fertile ground for the study of sensory processing. With the growing sophistication of touch-based behavioral paradigms, together with advances in neurophysiological methodology, a new approach is emerging. By posing increasingly complex perceptual and memory problems, in many cases analogous to human psychophysical tasks, investigators now explore the operations underlying rodent problem solving. We define the neural basis of tactile cognition as the transformation from a stage in which neuronal activity encodes elemental features, local in space and in time, to a stage in which neuronal activity is an explicit representation of the behavioral operations underlying the current task. Selecting a set of whisker-based behavioral tasks, we show that rodents achieve high level performance through the workings of neuronal cir-cuits that are accessible, decodable, and manipulatable. As a means towards exploring tactile cognition, this review presents leading psychophysical paradigms and, where known, their neural correlates
Multi-objective optimal control of ascent trajectories for launch vehicles
This paper presents a novel approach to the solution of multi-objective optimal control problems. The proposed solution strategy is based on the integration of the Direct Finite Elements Transcription method, to transcribe dynamics and objectives, with a memetic strategy called Multi Agent Collaborative Search (MACS). The original multi-objective optimal control problem is reformulated as a bi-level nonlinear programming problem. In the outer level, handled by MACS, trial control vectors are generated and passed to the inner level, which enforces the solution feasibility. Solutions are then returned to the outer level to evaluate the feasibility of the corresponding objective functions, adding a penalty value in the case of infeasibility. An optional single level refinement is added to improve the ability of the scheme to converge to the Pareto front. The capabilities of the proposed approach will be demonstrated on the multi-objective optimisation of ascent trajectories of launch vehicles
Return and abort trajectory optimisation for reusable launch vehicles
Among the future space access vehicles, the lifting body spaceplane is the most promising approach to prevent damage to both the launcher and the payload in case of loss of thrust. The glide performances of the vehicle allow the recovery in both nominal and abort cases. The approach presented is used in the investigation of the unpowered descent paths of a sample vehicle through trajectory optimisation. The vehicle's downrange and crossrange limits are obtained for aborts in multiple flight conditions
Predictive value of hematological and phenotypical parameters on postchemotherapy leukocyte recovery
Background: Grade IV chemotherapy toxicity is defined as absolute neutrophil count <500/μL. The nadir is considered as the lowest neutrophil number following chemotherapy, and generally is not expected before the 7th day from the start of chemotherapy. The usual prophylactic dose of rHu-G-CSF (Filgrastim) is 300 μg/day, starting 24-48 h after chemotherapy until hematological recovery. However, individual patient response is largely variable, so that rHu-G-CSF doses can be different. The aim of this study was to verify if peripheral blood automated flow cytochemistry and flow cytometry analysis may be helpful in predicting the individual response and saving rHu-G-CSF. Methods: During Grade IV neutropenia, blood counts from 30 cancer patients were analyzed daily by ADVIA 120 automated flow cytochemistry analyzer and by Facscalibur flow cytometer till the nadir. "Large unstained cells" (LUCs), myeloperoxidase index (MPXI), blasts, and various cell subpopulations in the peripheral blood were studied. At nadir rHu-G-CSF was started and 81 chemotherapy cycles were analyzed. Cycles were stratified according to their number and to two dose-levels of rHuG-CSF needed to recovery (300-600 vs. 900-1200 μg) and analyzed in relation to mean values of MPXI and mean absolute number of LUCs in the nadir phase. The linear regressions of LUCs % over time in relation to two dose-levels of rHu-G-CSF and uni-multivariate analysis of lymphocyte subpopulations, CD34+ cells, MPXI, and blasts were also performed. Results: In the nadir phase, the increase of MPXI above the upper limit of normality (>10; median 27.7), characterized a slow hematological recovery. MPXI levels were directly related to the cycle number and inversely related to the absolute number of LUCs and CD34 +/CD45+ cells. A faster hematological recovery was associated with a higher LUC increase per day (0.56% vs. 0.25%), higher blast (median 36.7/μL vs. 19.5/μL) and CD34+/CD45+ cell (median 2.2/μL vs. 0.82/μL) counts. Conclusions: Our study showed that some biological indicators such as MPXI, LUCs, blasts, and CD34 +/CD45+ cells may be of clinical relevance in predicting individual hematological response to rHu-G-CSF. Special attention should be paid when nadir MPXI exceeds the upper limit of normality because the hematological recovery may be delayed. © 2009 Clinical Cytometry Society
First description of early developmental stages of the native invasive fireworm Hermodice carunculata (Annelida, Amphinomidae): A cue to the warming of the mediterranean sea
Observations on the reproductive behavior and larval development of the bristled fireworm Hermodice carunculata, a common inhabitant of shallow marine rocky bottoms in the Southern Mediterranean Sea, are reported here. In recent years, an increase in abundance and a northward expansion of the populations along the Southern Italian coast were jointly detected, presumably linked to rising water temperature in the Mediterranean Sea. After making in situ observations on two consecutive spawning events, live worms and fresh spawn were brought into the lab, kept at either 27°C or 22°C and followed through development. Complete and normal development was observed only at 27°C. By contrast, embryonic and larval development appeared to be slowed down at 22°C, stopping at the protrochophora stage. Early development of H. carunculata suggests the existence of a long pre-metamorphic, planktotrophic period in the water column that can explain the genetic cohesion of this species and the low genetic divergence found among populations across the Atlantic Ocean. The observed increase in abundance, invasiveness potential, and geographical northern distribution of the bearded fireworms is probably determined by a progressive northward latitudinal shift of the sea surface temperature coincident with the temperature threshold required for the developmental and reproductive success of the worm
Capitate-trapezoid synostosis: analysis of an Early Bronze Age case and review of the literature
Background: Carpal synostoses are congenital defects characterised by complete or incomplete coalition of two or more carpal bones. Although most of these defects are discovered only incidentally, sometimes they become clinically manifest. Among the different types of carpal coalition, the synostosis between capitate and trapezoid bones is quite rare, with only sparse data available in the literature. The aim of this report was to describe a case of capitate-trapezoid synostosis (CTS) observed in an ancient human skeleton, as well as to scrutinise the pertinent literature in order to assess for the characteristics of this type of defect, including its potential relevance to clinical practice.
Materials and methods: We studied the skeletal remains of an Early Bronze Age male warrior affected by incomplete CTS. Macroscopic and radiological examination of the defect was carried out. We also performed a comprehensive PubMed search in the Medline and other specialty literature databases to retrieve and analyse data relevant to the subject under consideration.
Results and Conclusions: The present case is the most ancient CTS ever found. In those literature-reported cases accompanied by careful anatomical description, such as the present one, incomplete coalition invariably occurs between the dorsal surfaces of the two bones, this characteristic emerging as a distinctive morphological trait. Literature analysis further suggests that the true prevalence of CTS is likely to be higher than estimates based on data gathered from radiology series, and that this defect may be associated with pain and carpal bossing more frequently than generally though
Systematic review and meta-analysis of fibrin sealants for patients undergoing pancreatic resection
AbstractIntroductionPost-operative pancreatic fistula (POPF) is a common complication after partial pancreatic resection, and is associated with increased rates of sepsis, mortality and costs. The role of fibrin sealants in decreasing the risk of POPF remains debatable. The aim of this study was to evaluate the literature regarding the effectiveness of fibrin sealants in pancreatic surgery.MethodsA comprehensive database search was conducted. Only randomized controlled trials comparing fibrin sealants with standard care were included. A meta-analysis regarding POPF, intra-abdominal collections, post-operative haemorrhage, pancreatitis and wound infections was performed according to the recommendations of the Cochrane collaboration.ResultsSeven studies were included, accounting for 897 patients. Compared with controls, patients receiving fibrin sealants had a pooled odds ratio (OR) of developing a POPF of 0.83 [95% confidence interval (CI): 0.6–1.14], P = 0.245. There was a trend towards a reduction in post-operative haemorrhage (OR = 0.43 (95%CI: 0.18–1.0), P = 0.05) and intra-abdominal collections (OR = 0.52 (95%CI: 0.25–1.06), P = 0.073) in those patients receiving fibrin sealants. No difference was observed in terms of mortality, wound infections, re-interventions or hospital stay.ConclusionOn the basis of these results, fibrin sealants cannot be recommended for routine clinical use in the setting of pancreatic resection
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