Critical evaluation of restrictions used to optimize sterilization processing conditions

A computer program, using a finite differences method, was developed to model the heat sterilization for cylindrical packaged conduction heating foods. This program was introduced into an optimization routineto calculate optimum processing conditions, maximizing the surface or the volume average quality, using different restrictions. Depending on the pack dimensions and the heating rate of the product the least-lethality point is at the geometric center or along the radius or the vertical axis. Therefore, sterility values specified at the center and at the least-Iethality point were used as sterility criteria for calculating optimum conditions. The effect of an integrated sterility value constraint on optimal temperature was also investigated. Depending on the product thermal properties, processing conditions and target lethality the optimum temperature calculated using the sterility value at the center as restriction can overestimate the correet valueby as much as 4°C

Coastal regions of the northern Antarctic Peninsula are key for gentoo populations

Southern Ocean ecosystems are rapidly changing due to climate variability. An apparent beneficiary of such change in the western Antarctic Peninsula (WAP) is the gentoo penguin Pygoscelis papua, which has increased its population size and expanded its range southward in the last 20 years. To better understand how this species has responded to large-scale changes, we tracked individuals during the non-breeding winter period from five colonies across the latitudinal range of breeding sites in the WAP, including from a recently established colony. Results highlight latitudinal gradients in movement; strong associations with shallow, coastal habitats along the entire Antarctic Peninsula; and movements that are independent of, yet constrained by, sea ice. It is clear that coastal habitats essential to gentoo penguins during the breeding season are similarly critical during winter. Larger movements of birds from northern colonies in the WAP further suggest that leap-frog migration may influence colonization events by facilitating nest-area prospecting and use of new haul-out sites. Our results support efforts to develop a marine protected area around the WAP. Winter habitats used by gentoo penguins outline high priority areas for improving the management of the spatio-temporally concentrated krill (Euphausia superba) fishery that operates in this region during winter.Fil: Korczak Abshire, Malgorzata. Polish Academy of Sciences; ArgentinaFil: Hinke, Jefferson T.. National Ocean And Atmospheric Administration; Estados UnidosFil: Milinevsky, Gennadi. National Antarctic Scientific Center of Ukraine; Ucrania. National University of Kyiv; UcraniaFil: Juares, Mariana Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Ministerio de Relaciones Exteriores y Culto. Dirección Nacional del Antártico. Instituto Antártico Argentino. Departamento de Biología de Predadores Tope; ArgentinaFil: Watters, George M.. National Ocean And Atmospheric Administration; Estados Unido

Individual variation in migratory movements of chinstrap penguins leads to widespread occupancy of ice-free winter habitats over the continental shelf and deep ocean basins of the Southern Ocean

A goal of tracking migratory animals is to characterize the habitats they use and to interpret population processes with respect to conditions experienced en route to, and within, overwintering areas. For migratory seabirds with broad breeding ranges, inferring population-level effects of environmental conditions that are experienced during migratory periods would benefit by directly comparing how birds from different breeding aggregations disperse, characterizing the physical conditions of areas they use, and determining whether they occupy shared foraging areas. We therefore tracked 41 adult and juvenile chinstrap penguins (Pygoscelis antarctica) from three breeding locations in the northern Antarctic Peninsula region during the austral winter of 2017. The satellite tracking data revealed overlap of individuals over continental shelf areas during autumn months (MarMay), shared outbound corridors that track the southern Antarctic circumpolar current front, followed by occupancy of progressively colder, deeper, and ice-free waters that spanned the entire western hemisphere south of the Polar Front. Despite broadly similar physical environments used by individuals from different colonies, the proportion of birds from each colony that remained within 500km of their colony was positively correlated with their local population trends. This suggests that local migration strategies near the Antarctic Peninsula may benefit breeding populations. However, the magnitude of intercolony and intra-colony overlap was generally low given the broad scale of habitats occupied. High individual variation in winter movements suggests that habitat selection among chinstrap penguins is more opportunistic, without clear colony-specific preference for fine-scale foraging hotspots. Mixing of individuals from multiple colonies across broad regions of the Southern Ocean would expose chinstrap penguins from the Antarctic Peninsula to a shared environmental experience that helps explain the regional decline in their abundance

Surface Potential Driven Water Harvesting from Fog.

Access to clean water is a global challenge, and fog collectors are a promising solution. Polycarbonate (PC) fibers have been used in fog collectors but with limited efficiency. In this study, we show that controlling voltage polarity and humidity during the electrospinning of PC fibers improves their surface properties for water collection capability. We experimentally measured the effect of both the surface morphology and the chemistry of PC fiber on their surface potential and mechanical properties in relation to the water collection efficiency from fog. PC fibers produced at high humidity and with negative voltage polarity show a superior water collection rate combined with the highest tensile strength. We proved that electric potential on surface and morphology are crucial, as often designed by nature, for enhancing the water collection capabilities via the single-step production of fibers without any postprocessing needs

The Serotonin Transporter Promoter Polymorphism and Childhood Positive and Negative Emotionality

Association studies of the serotonin transporter promoter polymorphism (5-HTTLPR) and negative emotionality (NE) are inconclusive. However, emerging evidence suggests that the association between this polymorphism and NE may be influenced by levels of another temperament trait, positive emotionality (PE). Therefore, this study examined whether the association between the 5-HTTLPR and NE was moderated by PE. A community sample of 413 three-year-old children completed a standardized battery of laboratory tasks designed to tap temperamental emotionality. Children were also genotyped for the 5-HTTLPR. No direct association between 5-HTTLPR genotype and NE was found. However, the interaction of child PE and NE predicted 5-HTTLPR genotype. Furthermore, children with a short allele who were also low in PE had significantly greater NE than children without a short allele or children with high PE. Our findings suggest that the short allele of the 5-HTTLPR is associated with NE only in the context of low PE. Inconsistent links between NE and this gene in previous research may stem from the failure to consider other temperament traits that moderate associations. © 2010 American Psychological Association

Ultrathin 2 nm gold as ideal impedance-matched absorber for infrared light

Thermal detectors are a cornerstone of infrared (IR) and terahertz (THz) technology due to their broad spectral range. These detectors call for suitable broad spectral absorbers with minimalthermal mass. Often this is realized by plasmonic absorbers, which ensure a high absorptivity butonly for a narrow spectral band. Alternativly, a common approach is based on impedance-matching the sheet resistance of a thin metallic film to half the free-space impedance. Thereby, it is possible to achieve a wavelength-independent absorptivity of up to 50 %, depending on the dielectric properties of the underlying substrate. However, existing absorber films typicallyrequire a thickness of the order of tens of nanometers, such as titanium nitride (14 nm), whichcan significantly deteriorate the response of a thermal transducers. Here, we present the application of ultrathin gold (2 nm) on top of a 1.2 nm copper oxide seed layer as an effective IR absorber. An almost wavelength-independent and long-time stable absorptivity of 47(3) %, ranging from 2 $\mu$m to 20 $\mu$m, could be obtained and is further discussed. The presented gold thin-film represents analmost ideal impedance-matched IR absorber that allows a significant improvement of state-of-the-art thermal detector technology