1,906 research outputs found
Impact of modified atmosphere and humidity packaging on the quality, off-odour development and volatiles of ‘Elsanta’ strawberries
Development of off-odours, as well as visual quality of packaged fresh produce plays a crucial role in consumer’s choice. In this context, this work investigated the odour profile, condensation, gas composition, and postharvest quality attributes of strawberries stored under modified atmosphere and humidity packaging at 5 °C for 14 days. The packages were fitted with fixed area (69, 126.5, and 195.5 cm2) of different permeable membranes (NatureFlex, Xtend, and Propafilm). No significant changes were detected on the measured physicochemical quality attributes of strawberries and mass loss was below 1.5% across the different packaging systems. Package modification/design had an influence on in-package water vapour condensation, gas composition, and accumulation of secondary volatile organic compounds (acetaldehyde, acetone, ethanol and ethyl acetate)
Transpiration and moisture evolution in packaged fresh horticultural produce and the role of integrated mathematical models: A review
Transpiration has various adverse effects on postharvest quality and the shelf-life of fresh fruit and vegetables (FFV). If not controlled, the water released through this process results in direct mass loss and moisture condensation inside packaged FFV. Condensation represents a threat to the product quality as water may accumulate on the product surface and/or packaging system, causing defects in external appearance and promoting growth of spoilage microorganisms. Thus, moisture regulation is extremely important for extending FFV shelf-life. This review focuses on transpiration phenomenon and moisture evolution in packaged fresh horticultural produce. It provides recent information on various moisture control strategies suitable for packaging of fresh horticultural produce. It also provides an evaluation on the role and application of integrative mathematical modelling in describing water relations of FFV for packaging design, as well as, an overview of models reported in literature
Hydrogen production by photoelectrolytic decomposition of H2O using solar energy
Photoelectrochemical systems for the efficient decomposition of water are discussed. Semiconducting d band oxides which would yield the combination of stability, low electron affinity, and moderate band gap essential for an efficient photoanode are sought. The materials PdO and Fe-xRhxO3 appear most likely. Oxygen evolution yields may also be improved by mediation of high energy oxidizing agents, such as CO3(-). Examination of several p type semiconductors as photocathodes revealed remarkable stability for p-GaAs, and also indicated p-CdTe as a stable H2 photoelectrode. Several potentially economical schemes for photoelectrochemical decomposition of water were examined, including photoelectrochemical diodes and two stage, four photon processes
Nonlinear stability analysis of plane Poiseuille flow by normal forms
In the subcritical interval of the Reynolds number 4320\leq R\leq R_c\equiv
5772, the Navier--Stokes equations of the two--dimensional plane Poiseuille
flow are approximated by a 22--dimensional Galerkin representation formed from
eigenfunctions of the Orr--Sommerfeld equation. The resulting dynamical system
is brought into a generalized normal form which is characterized by a
disposable parameter controlling the magnitude of denominators of the normal
form transformation. As rigorously proved, the generalized normal form
decouples into a low--dimensional dominant and a slaved subsystem. {}From the
dominant system the critical amplitude is calculated as a function of the
Reynolds number. As compared with the Landau method, which works down to
R=5300, the phase velocity of the critical mode agrees within 1 per cent; the
critical amplitude is reproduced similarly well except close to the critical
point, where the maximal error is about 16 per cent. We also examine boundary
conditions which partly differ from the usual ones.Comment: latex file; 4 Figures will be sent, on request, by airmail or by fax
(e-mail address: rauh at beta.physik.uni-oldenburg.de
Moisture absorption kinetics of FruitPad for packaging of fresh strawberry
This study analysed the moisture absorption kinetics of FruitPad embedded with different concentrations of fructose with further application of such pads in packaging of fresh strawberries. The FruitPad was exposed to different storage conditions (temperature and RH) and moisture absorption kinetics was gravimetrically determined over 5 days of storage. FruitPad with 30% fructose showed highest amount of moisture absorption (0.94 g of water/g of pad) at 20 °C and 100% RH. The Weibull model combined with the Flory-Huggins model adequately described changes in moisture content of the FruitPad with respect to storage time and humidity (R2 = 93–96%). The FruitPad containing fructose minimized in-package condensation compared to the pad without fructose. Weight loss of packaged strawberry was less than 0.9% which was much below the acceptable limit of 6% for strawberry
Preseason Functional Test Scores are Associated with Future Sports Injury in Female Collegiate Athletes
Brumitt, J, Heiderscheit, B, Manske, R, Niemuth, PE, Mattocks, A, and Rauh, MJ. Preseason functional test scores are associated with future sports injury in female collegiate athletes. J Strength Cond Res 32(6): 1692–1701, 2018—Recent prospective cohort studies have reported preseason functional performance test (FPT) measures and associations with future risk of injury; however, the findings associated with these studies have been equivocal. The purpose of this study was to determine the ability of a battery of FPTs as a preseason screening tool to identify female Division III (D III) collegiate athletes who may be at risk for a noncontact time-loss injury to the lower quadrant (LQ = low back and lower extremities). One hundred six female D III athletes were recruited for this study. Athletes performed 3 FPTs: standing long jump (SLJ), single-leg hop (SLH) for distance, and the lower extremity functional test (LEFT). Time-loss sport-related injuries were tracked during the season. Thirty-two (24 initial and 8 subsequent) time-loss LQ injuries were sustained during the study. Ten of the 24 initial injuries occurred at the thigh and knee. At-risk athletes with suboptimal FPT measures (SLJ #79% ht; (B) SLH #64% ht; LEFT $118 seconds) had significantly greater rates of initial (7.2 per 1,000 athletic exposures [AEs]) and total (7.6 per 1,000 AEs) time-loss thigh or knee injuries than the referent group (0.9 per 1,000 AEs; 1.0 per 1,000 AEs, respectively). At-risk athletes were 9 times more likely to experience a thigh or knee injury (odds ratio [OR] = 9.7, confidence interval [CI]: 2.3–39.9; p = 0.002) than athletes in the referent group. At-risk athletes with a history of LQ sports injury and lower off-season training habits had an 18-fold increased risk of a time-loss thigh or knee injury during the season (adjusted OR = 18.7, CI: 3.0–118.1; p = 0.002). This battery of FPTs appears useful as a tool for identifying female D III athletes at risk of an LQ injury, especially to the thigh or knee region
Hofstadter butterfly for a finite correlated system
We investigate a finite two-dimensional system in the presence of external
magnetic field. We discuss how the energy spectrum depends on the system size,
boundary conditions and Coulomb repulsion. On one hand, using these results we
present the field dependence of the transport properties of a nanosystem. In
particular, we demonstrate that these properties depend on whether the system
consists of even or odd number of sites. On the other hand, on the basis of
exact results obtained for a finite system we investigate whether the
Hofstadter butterfly is robust against strong electronic correlations. We show
that for sufficiently strong Coulomb repulsion the Hubbard gap decreases when
the magnetic field increases.Comment: 7 pages, 5 figures, revte
Epidemiology of NCAA Track and Field Injuries From 2010 to 2014
Background:
Track and field (T&F) athletes compete in a variety of events that require different skills and training characteristics. Descriptive epidemiology studies often fail to describe event-specific injury patterns. Purpose:
To describe the epidemiology of injuries in National Collegiate Athletic Association (NCAA) T&F by sex, setting (practice vs competition), and time of season (indoor vs outdoor) and to compare injury patterns by events within the sport. Study Design:
Descriptive epidemiology study. Methods:
Data were obtained from the NCAA Injury Surveillance Program for all indoor and outdoor T&F injuries during the academic years 2009-2010 to 2013-2014. Injury rates, injury rate ratios, and injury proportion ratios (IPRs) were reported and compared by sex, injury setting, season, and event. Analysis included time-loss as well as no-time loss injuries. Results:
Over the 5 seasons, the overall injury rate was 3.99 injuries per 1000 athletic-exposures (95% CI, 3.79-4.20). After controlling for injury diagnoses, women’s T&F athletes experienced an 18% higher risk of injury (95% CI, 7% to 31%) and missed 41% more time after an injury (95% CI, 4% to 93%) when compared with men. Among all athletes, the injury risk during competition was 71% higher (95% CI, 50% to 95%) compared with practice and required 59% more time loss (95% CI, 7% to 135%). Distance running accounted for a significantly higher proportion of overuse injuries (IPR, 1.70; 95% CI, 1.40-2.05; P \u3c .05) and required 168% more time loss (95% CI, 78% to 304%) than other events. The hip and thigh were the body regions most commonly injured; injury type, however, varied by T&F event. Sprinting accounted for the greatest proportion of hip and thigh injuries, distance running had the greatest proportion of lower leg injuries, and throwing reported the greatest proportion of spine and upper extremity injuries. Conclusion:
Injury risk in NCAA T&F varied by sex, season, and setting. Higher injury rates were found in women versus men, indoor versus outdoor seasons, and competitions versus practices. The hip and thigh were the body regions most commonly injured; however, injury types varied by event. These findings may provide insight to programs aiming to reduce the risk of injury and associated time loss in collegiate T&F
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Total Pelvic Exenteration for Gynecologic Malignancies
Total pelvic exenteration (PE) is a radical operation, involving en bloc resection of pelvic organs, including reproductive structures, bladder, and rectosigmoid. In gynecologic oncology, it is most commonly indicated for the treatment of advanced primary or locally recurrent cancer. Careful patient selection and counseling are of paramount importance when considering someone for PE. Part of the evaluation process includes comprehensive assessment to exclude unresectable or metastatic disease. PE can be curative for carefully selected patients with gynecologic cancers. Major complications can be seen in as many as 50% of patients undergoing PE, underscoring the need to carefully discuss risks and benefits of this procedure with patients considering exenterative surgery
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