699 research outputs found
Monitoring the performance of residents during training in off-pump coronary surgery.
OBJECTIVE: Control charts (eg, cumulative sum charts) plot changes in performance with time and can alert a surgeon to suboptimal performance. They were used to compare performance of off-pump coronary artery bypass surgery between a consultant and four resident surgeons and to compare performance of off-pump coronary artery bypass surgery and conventional coronary artery bypass grafting within surgeons. METHODS: Data were analyzed for consecutive patients undergoing coronary artery bypass grafting who were operated on by one consultant or one of four residents. Conversions were analyzed by intention to treat. Perioperative death or one or more of 10 adverse events constituted failure. Predicted risks of failure for individual patients were derived from the study population. Variable life-adjusted displays and risk-adjusted sequential probability ratio test charts were plotted. RESULTS: Data for 1372 patients were analyzed; 769 of the procedures were off-pump coronary artery bypass operations (56.0%). The consultant operated on 382 patients (293 off-pump, 76.7%), and the residents operated on 990 (474 off-pump, 47.9%). Patients operated on by residents tended to be older, more obese, more likely to require an urgent operation, and more likely to need a circumflex artery graft but less likely to have triple-vessel disease. There were 7 conversions (consultant 5, residents 2). The overall failure rate was 8.5% (9.2% for consultant's operations and 8.2% for residents' operations), including 10 deaths (0.7%). Predicted and observed risks of failure were similar for all five surgeons. After 100 off-pump coronary artery bypass operations, performance was the same or better for the residents as for the consultant. For all surgeons, performance was the same or better for off-pump as for conventional coronary artery bypass grafting. CONCLUSIONS: Off-pump coronary artery bypass surgery can be safely taught to cardiothoracic residents. Implementation of continuous performance monitoring for residents is practicable
Effects of Water Volume and Nitrogen Fertilization on Yield and Quality Traits of Air-cured Burley Tobacco (Nicotianatabacum L.)
AbstractBased on a two-year field trial in the region of Campania (Southern Italy) the effects of water volume and nitrogen fertilization on the yield and quality of Burley tobacco (Nicotianatabacum L.) were investigated with reference to the following traits: cured leaf yield, price index, yield value, leaf area, specific leaf weight, burning capacity, color parameters, total alkaloid, nitrate and chloride leaf content. The experimental design was a factorial comparison among three water volumes (40, 80 and 120% evapotranspiration (ET)), four nitrogen fertilization levels (0, 80, 160 and 240 kg ha-1) and two genotypes (cv TN86 and the hybrid R7-11). The yield of cured leaves rose with the increase in water and nitrogen availability, albeit at a decreasing rate. With the increase in water volume, the price index, burning capacity, specific leaf weight, total alkaloid and nitrate content decreased, while leaf area and chloride content increased. Up to a rate of 160 kg ha-1, nitrogen fertilization increased the price index, yield value, burning capacity, leaf area, specific leaf weight, total alkaloid and nitrates, and reduced leaf chloride content especially at 40% ET water volume. Both, nitrogen fertilization and water volume had little influence on leaf color. The year had considerable effects on yield, leaf area and color parameters, with higher values in the rainier season. In the two years, genotype TN86 showed higher stability for yield and yield value, lower alkaloid and higher nitrate content in the leaf than the R7-11 hybrid
Effect of Water Regime and Nitrogen Fertilisation on Growth Dynamics, Water Status and Yield of Burley Tobacco (Nicotianatabacum L.)
AbstractThe results of a two-year research project into burley tobacco are reported and discussed. Three irrigation levels (40, 80 and 120% restitution of evapotranspiration (ET)) were factorially combined with four levels of nitrogen fertilisation (0, 80, 160 and 240 kg ha). Leaf area, leaf and stem dry matter and root development were measured. We monitored the water status of the 0-90 cm soil layer, the plants and stomatal resistance. Relations were also studied between leaf turgor pressure and plant growth, between the irrigation regime and plant water status, and between root and shoot development. Finally, water use efficiency (WUE) and quality and quantity of cured leaves yields were evaluated. Nitrogen fertilisation did not affect plant water status, although it promoted plant growth, both in terms of leaf area and leaf and stem dry matter, and induced a yield increase in quantity and quality. Our trial showed little interaction between nitrogen fertilization level and water regime. Under such agronomic condition, the margins for increasing plant growth with nitrogen fertilization are limited, which is why application of nitrogen rates in excess of 160 kg haappear inadvisable. The difference in irrigation volumes led to a different soil water content which affected plant water status, stomatal functioning, plant growth, both in the roots and shoots, yield and quality of the cured leaves. The latter did not vary with the increase in water volume, while yield increased. Water use efficiency increased as the irrigation volume decreased and varied during the cropping cycle, increasing until early bloom, then decreasing. Relations between leaf turgor pressure and plant growth highlighted the different response of plants subjected to water stress compared with non-stressed plants
Effects of partially defatted Hermetia illucens meal in rainbow trout diet on hepatic methionine metabolism.
This study investigated, for the first time, the effects of replacement of fishmeal (FM) with insect meal from Hermetia illucens (HI) on the transcript levels of three genes involved in methionine (Met) metabolism in rainbow trout (Oncorhynchus mykiss) liver. Two target genes\u2014betaine-homocysteine S-methyltransferase (BHMT) and S-adenosylhomocysteine hydrolase (SAHH)\u2014are involved in Met resynthesis and the third one\u2014cystathionine \u3b2 synthase (CBS)\u2014is involved in net Met loss (taurine synthesis). We also investigated the levels of two Met metabolites involved in the maintenance of methyl groups and homocysteine homeostasis in the hepatic tissue: S-adenosylmethionine (SAM) and S-adenosylhomocysteine (SAH). Three diets were formulated, an FM-based diet (HI0) and two diets in which 25% (HI25) and 50% (HI50) of FM was replaced with HI larvae meal. A 78-day feeding trial involved 360 rainbow trout with 178.9 \ub1 9.81 g initial average weight. Dietary replacement of up to 50% of FM with HI larvae meal, without any Met supplementation, did not negatively affect rainbow trout growth parameters and hepatic Met metabolism. In particular, Met availability from the insect-based diets directly modulated the transcript levels of two out of three target genes (CBS, SAHH) to maintain an optimal level of one-carbon metabolic substrates, i.e., the SAM:SAH ratio in the hepatic tissue
PS-inSAR data analysis: Pre-seismic ground deformation in the 2009 l’aquila earthquake region
The accuracy of the millimetre-scale measurements made so far by the SAR systems, as well as the multi-temporal analysis methodologies, have provided impressive images of surface displacements in areas affected by strong earthquakes, and contributed to constrain the geometric and kinematic features of earthquake generating faults. The multi-temporal analysis of InSAR data is also being acknowledged as promising for the search of earthquake precursors. We have applied the multi-temporal PS-InSAR technique to the detection of pre- to post-seismic ground displacements in the region struck by the normal faulting 2009 L’Aquila earthquake. We have used ERS and ENVISAT PS-data sets from both ascending and descending orbits, covering a 20-year long time span. On the yearly-scale, we have identified a pre-seismic displacement pattern, which consists of opposite vertical motions that have affected the blocks in the hanging wall and footwall of the structure that is recognised as the surface trace of the earthquake-generating fault. In particular, we have highlighted a pre-seismic uplift for 4-5 years followed by subsidence (starting 6-8 months prior to the earthquake) of the hanging wall block, coeval to opposite vertical motions of the footwall block. We suggest that such a displacement pattern may represent an earthquake precursor signal
Factors influencing the prevalence of animal cruelty during adolescence
Adolescents’ interactions with animals are of increasing interest and their beneficial developmental outcomes are well known. However, negative interactions such as perpetrating cruelty toward animals during childhood and adolescence have been related with child abuse, domestic violence, and later interpersonal violence. Cruelty toward animals by adolescents has been reported predominately in criminal and clinical samples, and links have been made between animal cruelty and interpersonal violence. However, studies often lack a clear definition of animal cruelty and the animal involved. The present study addresses methodological shortcomings by providing a clear definition of the cruelty acts and the animals involved and the time frame within which cruelty acts have been taken place. Therefore, we investigated the prevalence of animal cruelty of 979 British adolescents (419 male, 497 female, Mage = 15.1 ± 1.57 years) by means of a survey questionnaire administered in school. Animal cruelty was investigated encompassing deliberate and nondeliberate cruelty acts, a clear definition of the target animals was included and a time frame was provided. Furthermore, acceptability of animal cruelty, engaging in antisocial behavior, and family affluence were investigated. Results show high reliabilities for the measures applied. Exploratory factor analysis reveals different types of animal cruelty. Gender differences were observed for deliberate and accidental cruelty acts, with boys reporting higher levels than girls. Younger adolescents reported higher accidental cruelty acts than older ones. Acceptance of animal cruelty played a significant role in predicting animal cruelty, together with antisocial behaviors and place of living. The present study shows for the first time the importance of distinguishing between different types of animal cruelty and defining the animals involved.PostprintPeer reviewe
The Plio-Quaternary uplift of the Apennine Chain: new data from the analysis of topography and river valleys in Central Italy
This study aimed at the reconstruction of magnitude and timing of uplift of a wide sector of the
Central Apennines (Italy) by means of morphometric and morphostructural analyses. In the internal
portion of the chain (where stratigraphic and geomorphological markers of past sea-level positions
are lacking) the study was based on analysis of erosional landforms and river valleys.
A large-scale topographic analysis was performed, processing 90-m and 230-m DEMs. The
spatial distribution of several morphometric parameters, together with characteristic wavelengths of
relief, allowed the distinction of three main regions affected by different cumulative surface uplift
and tectonic/erosional fragmentation: a Peri-Tyrrhenian Belt; an Axial Belt; a Peri-Adriatic Belt.
Particular attention was devoted to fluvial landforms, with analysis of longitudinal profiles and
geometric pattern of the main stream-trunks and their relations with major structures. Major
differences occur between the Tyrrhenian and Adriatic valley systems, the former being generally
longitudinal and showing overall concave-upward longitudinal profiles, whereas the latter are
generally transverse and possess less regular longitudinal profiles. Topographic features and river
valleys architecture seem related to different styles and amounts of uplift in the three Belts.
Within the study area, a narrower coast to coast transect (Gaeta-Vasto Transect, GVT) was
investigated in detail, devoting particular attention to its axial sector, lying around the Apennines
main divide (main divide area: MDA), and a possible scheme of the Quaternary surface uplift inside
this transect was proposed. In the MDA, the main stages of landscape evolution and river network
organization were reconstructed by analysis of paleosurfaces coupled with analysis of relic and
present-day hydrographic network. This allowed recognition of a major phase of surface uplift
(exceeding 1500 m in the Meta-Mainarde massif) occurred in response to thrusting during the
Pliocene, whereas for the Quaternary uplift a minimum value around 400 m was estimated.
Our study suggests that, during the Quaternary and in the GVT, the Peri-Tyrrhenian Belt
suffered a subdued uplift operating over small wavelengths (10-15 km), while Axial and Peri-
Adriatic Belts were subject to a stronger and long-wavelength (90 km) surface uplift, with
maximum values (about 700 m) shifted NE of the Axial Belt and tapering to zero towards the
Adriatic coast. The reconstructed pattern of uplift is coherent with the topographic properties of the
three Belts and with the observed drainage features
In situ monolayer patch clamp of acutely stimulated human iPSC-derived cardiomyocytes promotes consistent electrophysiological responses to SK channel inhibition
Human induced pluripotent stem cell-derived cardiomyocytes (iPSC-CMs) represent an in vitro model of cardiac function. Isolated iPSC-CMs, however, exhibit electrophysiological heterogeneity which hinders their utility in the study of certain cardiac currents. In the healthy adult heart, the current mediated by small conductance, calcium-activated potassium (SK) channels (ISK) is atrial-selective. Functional expression of ISK within atrial-like iPSC-CMs has not been explored thoroughly. The present study therefore aimed to investigate atrial-like iPSC-CMs as a model system for the study of ISK. iPSCs were differentiated using retinoic acid (RA) to produce iPSC-CMs which exhibited an atrial-like phenotype (RA-iPSC-CMs). Only 18% of isolated RA-iPSC-CMs responded to SK channel inhibition by UCL1684 and isolated iPSC-CMs exhibited substantial cell-to-cell electrophysiological heterogeneity. This variability was significantly reduced by patch clamp of RA-iPSC-CMs in situ as a monolayer (iPSC-ML). A novel method of electrical stimulation was developed to facilitate recording from iPSC-MLs via In situ Monolayer Patch clamp of Acutely Stimulated iPSC-CMs (IMPASC). Using IMPASC, > 95% of iPSC-MLs could be paced at a 1 Hz. In contrast to isolated RA-iPSC-CMs, 100% of RA-iPSC-MLs responded to UCL1684, with APD50 being prolonged by 16.0 ± 2.0 ms (p < 0.0001; n = 12). These data demonstrate that in conjunction with IMPASC, RA-iPSC-MLs represent an improved model for the study of ISK. IMPASC may be of wider value in the study of other ion channels that are inconsistently expressed in isolated iPSC-CMs and in pharmacological studies.<br/
Integrating expert opinions with clinical trial data to analyse low-powered subgroup analyses:a Bayesian analysis of the VeRDiCT trial
Heterogeneity of T-Tubules in Pig Hearts
BACKGROUND:T-tubules are invaginations of the sarcolemma that play a key role in excitation-contraction coupling in mammalian cardiac myocytes. Although t-tubules were generally considered to be effectively absent in atrial myocytes, recent studies on atrial cells from larger mammals suggest that t-tubules may be more numerous than previously supposed. However, the degree of heterogeneity between cardiomyocytes in the extent of the t-tubule network remains unclear. The aim of the present study was to investigate the t-tubule network of pig atrial myocytes in comparison with ventricular tissue. METHODS:Cardiac tissue was obtained from young female Landrace White pigs (45-75 kg, 5-6 months old). Cardiomyocytes were isolated by arterial perfusion with a collagenase-containing solution. Ca2+ transients were examined in field-stimulated isolated cells loaded with fluo-4-AM. Membranes of isolated cells were visualized using di-8-ANEPPS. T-tubules were visualized in fixed-frozen tissue sections stained with Alexa-Fluor 488-conjugated WGA. Binary images were obtained by application of a threshold and t-tubule density (TTD) calculated. A distance mapping approach was used to calculate half-distance to nearest t-tubule (HDTT). RESULTS & CONCLUSION:The spatio-temporal properties of the Ca2+ transient appeared to be consistent with the absence of functional t-tubules in isolated atrial myocytes. However, t-tubules could be identified in a sub-population of atrial cells in frozen sections. While all ventricular myocytes had TTD >3% (mean TTD = 6.94±0.395%, n = 24), this was true of just 5/22 atrial cells. Mean atrial TTD (2.35±0.457%, n = 22) was lower than ventricular TTD (P3% (1.65±0.06 μm, n = 5, P<0.05). These data demonstrate considerable heterogeneity between pig cardiomyocytes in the extent of t-tubule network, which correlated with cell size
- …