convective warming
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2020 ◽  
Vol 42 ◽  
pp. e9
Author(s):  
Deise Rodrigues Barcellos ◽  
Mônica Aparecida Dias Wolf ◽  
Sérgio Roberto Sanches ◽  
Mário Francisco Leal de Quadro

The excess or deficiency of precipitation directly affects environmental conditions, influencing society and its various economic sectors. This study analyzes the variability of precipitation in Florianópolis / SC, using the Rain Anomaly Index (RAI). To identify possible changes in the precipitation pattern, non-parametric tests are performed with a 5% significance and linear regression with a 95% confidence level in the data from the Climate Prediction Center (CPC) during the period 1979 to 2017. The results show that the most of the positive (negative) precipitation indexes correspond to the years of the warm (cold) phase of the Pacific Decadal Oscillation (PDO), and with the highest frequency of El Niño (La Niña) events. Annual time series indicate a decline in precipitation. It is also observed: (i) a small tendency to reduce rainfall in summer, autumn and winter; (ii) a significant tendency to reduce rainfall in the spring (61.4 mm in the period) and (iii) a reduction of 7.9 mm / year and a total of 308.6 mm in the period. It can be infer that rainfall totals in the months of greatest convective warming are decreasing in recent years due to the reduction in the number of rainy days or extreme rainfall.



2018 ◽  
Vol 20 (1) ◽  
pp. 301-327 ◽  
Author(s):  
John C. Bischof ◽  
Kenneth R. Diller

This review explores bioheat transfer applications at multiple scales from nanoparticle (NP) heating to whole-body thermoregulation. For instance, iron oxide nanoparticles are being used for nanowarming, which uniformly and quickly rewarms 50–80-mL (≤5-cm-diameter) vitrified systems by coupling with radio-frequency (RF) fields where standard convective warming fails. A modification of this approach can also be used to successfully rewarm cryopreserved fish embryos (∼0.8 mm diameter) by heating previously injected gold nanoparticles with millisecond pulsed laser irradiation where standard convective warming fails. Finally, laser-induced heating of gold nanoparticles can improve the sensitivity of lateral flow assays (LFAs) so that they are competitive with laboratory tests such as the enzyme-linked immunosorbent assay. This approach addresses the main weakness of LFAs, which are otherwise the cheapest, easiest, and fastest to use point-of-care diagnostic tests in the world. Body core temperature manipulation has now become possible through selective thermal stimulation (STS) approaches. For instance, simple and safe heating of selected areas of the skin surface can open arteriovenous anastomosis flow in glabrous skin when it is not already established, thereby creating a convenient and effective pathway to induce heat flow between the body core and environment. This has led to new applications of STS to increase or decrease core temperatures in humans and animals to assist in surgery (perioperative warming), to aid ischemic stress recovery (cooling), and even to enhance the quality of sleep. Together, these multiscale applications of nanoparticle heating and thermoregulation point to dramatic opportunities for translation and impact in these prophylactic, preservative, diagnostic, and therapeutic applications of bioheat transfer.



2016 ◽  
Vol 65 (05) ◽  
pp. 362-366 ◽  
Author(s):  
Robert Franke ◽  
Ivo Brandes ◽  
Marc Hinterthaner ◽  
Bernhard Danner ◽  
Martin Bauer ◽  
...  

Background Perioperative hypothermia is frequent during thoracic surgery. After approval by the local ethics committee and written informed consent from patients, we examined the efficiency of prewarming and intraoperative warming with a convective warming system and conductive warming system to prevent perioperative hypothermia during video-assisted thoracic surgery (VATS). Methods We randomized 60 patients with indication for VATS in two groups (convective warming with an underbody blanket vs. conductive warming with an underbody mattress and additional warming of the legs). All patients were prewarmed before induction of anesthesia with the corresponding system. Core temperature was measured sublingual and in the nasopharynx. Results Both groups were not significantly different in regard to clinical parameter, prewarming, and initial core temperature. The patients in conduction group had lower intraoperative core temperatures and a higher incidence of intraoperative (73.9 vs. 24%) and postoperative hypothermia (56.5 vs. 8%) compared with convective warming. Conclusions Pre- and intraoperative convective warming with an underbody blanket prevents perioperative hypothermia during VATS better than conductive warming. The inferior prevention in conductive warming group may be caused by reduced body contact to the warming mattresses in lateral position.



2016 ◽  
Vol 2016 ◽  
pp. 1-7
Author(s):  
Hedwig Schroeck ◽  
Angela K. Lyden ◽  
Wendy L. Benedict ◽  
Satya Krishna Ramachandran

Background. Despite increasing adoption of active warming methods over the recent years, little is known about the effectiveness of these interventions on the occurrence of abnormal postoperative temperatures in sick infants.Methods. Preoperative and postoperative temperature readings, patient characteristics, and procedural factors of critically ill infants at a single institution were retrieved retrospectively from June 2006 until May 2014. The primary endpoints were the incidence and trend of postoperative hypothermia and hyperthermia on arrival at the intensive care units. Univariate and adjusted analyses were performed to identify factors independently associated with abnormal postoperative temperatures.Results. 2,350 cases were included. 82% were normothermic postoperatively, while hypothermia and hyperthermia each occurred in 9% of cases. During the study period, hypothermia decreased from 24% to 2% (p<0.0001) while hyperthermia remained unchanged (13% in 2006, 8% in 2014,p=0.357). Factors independently associated with hypothermia were higher ASA status (p=0.02), lack of intraoperative convective warming (p<0.001) and procedure date before 2010 (p<0.001). Independent associations for postoperative hyperthermia included lower body weight (p=0.01) and procedure date before 2010 (p<0.001).Conclusions. We report an increase in postoperative normothermia rates in critically ill infants from 2006 until 2014. Careful monitoring to avoid overcorrection and hyperthermia is recommended.







2008 ◽  
Vol 55 (6) ◽  
pp. 358-363 ◽  
Author(s):  
Karl Wagner ◽  
Erika Swanson ◽  
Clifford J. Raymond ◽  
Charles E. Smith


2007 ◽  
Vol 20 (2) ◽  
pp. 187-202 ◽  
Author(s):  
G. J. Shutts ◽  
T. N. Palmer

Abstract Idealized cloud-resolving model (CRM) simulations spanning a large part of the tropical atmosphere are used to evaluate the extent to which deterministic convective parameterizations fail to capture the statistical fluctuations in deep-convective forcing, and to provide probability distribution functions that may be used in stochastic parameterization schemes for global weather and climate models. A coarse-graining methodology is employed to deduce an effective convective warming rate appropriate to the grid scale of a forecast model, and a convective parameterization scheme is used to bin these computed tendencies into different ranges of convective forcing strength. The dependence of the probability distribution functions for the coarse-grained temperature tendency on parameterized tendency is then examined. An aquaplanet simulation using a climate model, configured with similar horizontal resolution to that of the coarse-grained CRM fields, was used to compare temperature tendency variation (less the effect of advection and radiation) with that deduced as an effective forcing function from the CRM. The coarse-grained temperature tendency of the CRM is found to have a substantially broader probability distribution function than the equivalent quantity in the climate model. The CRM-based probability distribution functions of precipitation rate and convective warming are related to the statistical mechanics theory of Craig and Cohen and the “stochastic physics” scheme of Buizza et al. It is found that the standard deviation of the coarse-grained effective convective warming is an approximately linear function of its mean, thereby providing some support for the Buizza et al. scheme, used operationally by ECMWF.



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