Predicting operator workload during system design

A workload prediction methodology was developed in response to the need to measure workloads associated with operation of advanced aircraft. The application of the methodology will involve: (1) conducting mission/task analyses of critical mission segments and assigning estimates of workload for the sensory, cognitive, and psychomotor workload components of each task identified; (2) developing computer-based workload prediction models using the task analysis data; and (3) exercising the computer models to produce predictions of crew workload under varying automation and/or crew configurations. Critical issues include reliability and validity of workload predictors and selection of appropriate criterion measures

New methods for detection and quantification of DNA in hair and their implementation in forensic medicine

Haare und Nägel sind Hautanhangsgebilde, bestehend aus verhornten Keratinozyten. Während der Verhornung wird die nukleäre DNA zum überwiegenden Teil abgebaut, der Mechanismus dieses Prozesses ist jedoch weitgehend unbekannt. Darüber hinaus haben forensische Untersuchungen ergeben, dass es möglich ist, DNA aus den Haaren mancher aber nicht aller Individuen aufzureinigen und zu typisieren; die biologische Grundlage für dieses Phänomen ist unklar. Die Ziele dieses Projekts waren (1) den Beitrag der Keratinozyten-spezifischen Endonuklease DNase1L2 im DNA-Abbau während der Verhornung zu quantifizieren und (2) die Ursache inter-individueller Unterschiede in der DNA-Ausbeute in forensischen Untersuchungen zu bestimmen. Neuartige Protokolle für in situ-Färbung von Kern-DNA in Haaren und für die Quantifizierung von aus Haaren und Nägeln extrahierter DNA wurden etabliert. Während die Kernfärbung in situ die Permeabilisierung der Haare und anschließende Inkubation mit DNA-spezifischen fluoreszierenden Farbstoffen beinhaltete, basierte die Quantifizierungsmethode auf der Amplifikation von DNA mittels real-time PCR. Vergleichende Untersuchungen mit Haaren und Nägeln von normalen Mäusen und von Mäusen mit fehlender Endonuclease DNase1L2 zeigten, dass DNase1L2 essentiell für den Abbau nukleärer DNA in Haaren und Nägeln sowie von mitochondrialer DNA in Nägeln ist. Screenings von humanen Haarproben mit in situ Kernfärbungen und DNA-Quantifizierung mittels PCR offenbarten eine signifikante Korrelation zwischen der Anzahl von anfärbbaren Zellkernen in Haaren und der extrahierbaren DNA-Menge. Die in situ Färbung von Kernresten in einzelnen Haaren ermöglichte eine Voraussage der Erfolgsrate von Genotypisierungen anhand von Short Tandem Repeats (STRs). Die Ergebnisse dieser Studie legen nahe, dass DNase1L2 eine entscheidende Rolle im DNA-Abbau in Haaren und Nägeln spielt und helfen dabei, Unterschiede in der DNA-Ausbeute von Haaren zu erklären. Die neue Kernfärbemethode für Haare könnte in zukünftigen forensischen Untersuchungen zur Anwendung kommen.Hairs and nails are skin appendages that consist of cornified keratinocytes. Nuclear DNA is largely degraded during cornification, however the mechanism of this process has remained elusive. Moreover, forensic investigations have indicated that DNA can be extracted and typed from hair of some individuals but not from others. The biological basis for this phenomenon has been unknown. The aims of this project were (1) to quantify the contribution of the keratinocyte-specific endonuclease DNase1L2 in the degradation of DNA during cornification and (2) to determine the cause of inter-individual differences in the yield of DNA for forensic investigations. Novel protocols for the in situ labeling of nuclear DNA in hair and for the quantification of DNA extracted from hair and nails were established. In situ labeling involved permeabilization of hair and incubation with DNA-specific fluorescent dyes, whereas DNA quantification was based on real-time PCR amplification. Comparative investigations of hair and nails from wild-type mice and mice deficient in the endonuclease DNase1L2 showed that DNase1L2 was essential for the breakdown of nuclear DNA in hair and nails as well as for degrading mitochondrial DNA in nails. Screening of human hair samples with in situ DNA labeling and DNA quantification by PCR revealed a significant correlation between the number of residual DNA in situ and the PCR yield. In situ labeling of DNA allowed the prediction of the success rate of short tandem repeat (STR) genotyping of single hairs. The results of this study suggest that DNase1L2 has a crucial role in the degradation of DNA in hair and nails and help to explain differences in DNA amplification yields from hair. The method of labeling DNA in hair samples may be applied in future forensic investigations

Evolution of shear zones in granular materials

The evolution of wide shear zones (or shear bands) was investigated experimentally and numerically for quasistatic dry granular flows in split bottom shear cells. We compare the behavior of materials consisting of beads, irregular grains (e.g. sand) and elongated particles. Shearing an initially random sample, the zone width was found to significantly decrease in the first stage of the process. The characteristic shear strain associated with this decrease is about unity and it is systematically increasing with shape anisotropy, i.e. when the grain shape changes from spherical to irregular (e.g. sand) and becomes elongated (pegs). The strongly decreasing tendency of the zone width is followed by a slight increase which is more pronounced for rod like particles than for grains with smaller shape anisotropy (beads or irregular particles). The evolution of the zone width is connected to shear induced density change and for nonspherical particles it also involves grain reorientation effects. The final zone width is significantly smaller for irregular grains than for spherical beads.Comment: 11 pages, 12 figures, submitted to Phys. Rev.

Effects of human-induced alteration of groundwater flow on concentrations of naturally-occurring trace elements at water-supply wells

AbstractThe effects of human-induced alteration of groundwater flow patterns on concentrations of naturally-occurring trace elements were examined in five hydrologically distinct aquifer systems in the USA. Although naturally occurring, these trace elements can exceed concentrations that are considered harmful to human health. The results show that pumping-induced hydraulic gradient changes and artificial connection of aquifers by well screens can mix chemically distinct groundwater. Chemical reactions between these mixed groundwaters and solid aquifer materials can result in the mobilization of trace elements such as U, As and Ra, with subsequent transport to water-supply wells. For example, in the High Plains aquifer near York, Nebraska, mixing of shallow, oxygenated, lower-pH water from an unconfined aquifer with deeper, confined, anoxic, higher-pH water is facilitated by wells screened across both aquifers. The resulting higher-O2, lower-pH mixed groundwater facilitated the mobilization of U from solid aquifer materials, and dissolved U concentrations were observed to increase significantly in nearby supply wells. Similar instances of trace element mobilization due to human-induced mixing of groundwaters were documented in: (1) the Floridan aquifer system near Tampa, Florida (As and U), (2) Paleozoic sedimentary aquifers in eastern Wisconsin (As), (3) the basin-fill aquifer underlying the California Central Valley near Modesto (U), and (4) Coastal Plain aquifers of New Jersey (Ra). Adverse water-quality impacts attributed to human activities are commonly assumed to be related solely to the release of the various anthropogenic contaminants to the environment. The results show that human activities including various land uses, well drilling, and pumping rates and volumes can adversely impact the quality of water in supply wells, when associated with naturally-occurring trace elements in aquifer materials. This occurs by causing subtle but significant changes in geochemistry and associated trace element mobilization as well as enhancing advective transport processes

Population dynamics, delta vulnerability and environmental change: comparison of the Mekong, Ganges–Brahmaputra and Amazon delta regions

Tropical delta regions are at risk of multiple threats including relative sea level rise and human alterations, making them more and more vulnerable to extreme floods, storms, surges, salinity intrusion, and other hazards which could also increase in magnitude and frequency with a changing climate. Given the environmental vulnerability of tropical deltas, understanding the interlinkages between population dynamics and environmental change in these regions is crucial for ensuring efficient policy planning and progress toward social and ecological sustainability. Here, we provide an overview of population trends and dynamics in the Ganges–Brahmaputra, Mekong and Amazon deltas. Using multiple data sources, including census data and Demographic and Health Surveys, a discussion regarding the components of population change is undertaken in the context of environmental factors affecting the demographic landscape of the three delta regions. We find that the demographic trends in all cases are broadly reflective of national trends, although important differences exist within and across the study areas. Moreover, all three delta regions have been experiencing shifts in population structures resulting in aging populations, the latter being most rapid in the Mekong delta. The environmental impacts on the different components of population change are important, and more extensive research is required to effectively quantify the underlying relationships. The paper concludes by discussing selected policy implications in the context of sustainable development of delta regions and beyond

DNase 2 Is the Main DNA-Degrading Enzyme of the Stratum Corneum

The cornified layer, the stratum corneum, of the epidermis is an efficient barrier to the passage of genetic material, i.e. nucleic acids. It contains enzymes that degrade RNA and DNA which originate from either the living part of the epidermis or from infectious agents of the environment. However, the molecular identities of these nucleases are only incompletely known at present. Here we performed biochemical and genetic experiments to determine the main DNase activity of the stratum corneum. DNA degradation assays and zymographic analyses identified the acid endonucleases L-DNase II, which is derived from serpinB1, and DNase 2 as candidate DNases of the cornified layer of the epidermis. siRNA-mediated knockdown of serpinB1 in human in vitro skin models and the investigation of mice deficient in serpinB1a demonstrated that serpinB1-derived L-DNase II is dispensable for epidermal DNase activity. By contrast, knockdown of DNase 2, also known as DNase 2a, reduced DNase activity in human in vitro skin models. Moreover, the genetic ablation of DNase 2a in the mouse was associated with the lack of acid DNase activity in the stratum corneum in vivo. The degradation of endogenous DNA in the course of cornification of keratinocytes was not impaired by the absence of DNase 2. Taken together, these data identify DNase 2 as the predominant DNase on the mammalian skin surface and indicate that its activity is primarily targeted to exogenous DNA

The value of twinned pollinator-pollen metabarcoding: Bumblebee pollination service is weakly partitioned within a UK grassland community

Predicting ecological impact of declining bumblebee (Bombus) populations requires better understanding of interactions between pollinator partitioning of floral resources and plant partitioning of pollinator resources. Here, we combine Cytochrome Oxidase 1 (CO1) barcoding for bumblebee identification and rbcL metabarcoding of pollen carried by bees in three species-rich UK pastures. CO1 barcoding assigned 272 bees to eight species, with 33 individuals belonging to the cryptic Bombus lucorumcomplex (16 B. lucorum and 17 B. cryptarum). Seasonal bias in capture rates varied by species, with B. pratorum found exclusively in June/July and B. pascuorum moreabundant in August. Pollen metabarcoding coupled with PERMANOVA and NMDS analyses revealed all bees carried several local pollen species and evidence of pollen resource partitioning between some species pairings, with Bombus pratorum carrying the most divergent pollen load. There was no evidence of resource partitioning between the two cryptic species present, but significantly divergent capture rates concorded with previous suggestions of separation on the basis of foraging behaviour being shaped by local/temporal differences in climatic conditions. Considering the bee carriage profile of pollen species revealed no significant difference between the ninemost widely carried plant species. However, there was a sharp, tipping point change in community pollen carriage across all three sites occurred during the transition between late July and early August. This transition resulted in a strong divergence in community pollen carriage between the two seasonal periods in both years. We conclude that the combined use of pollen and bee barcoding offers several benefits for further study of plant-pollinator interactions at the landscape scale

Ocotea nutans (Nees) Mez (Lauraceae): chemical composition, antioxidant capacity and biological properties of essential oil

The present study was undertaken to assess the potential uses of the essential oil obtained from Ocotea nutans (Nees) Mez. The hydrodistilled essential oil from O. nutans leaves was analyzed by gas chromatography-mass spectrometry. Fifty-eight compounds representing 87,29% of the total leaf essential oil components were identified, of which biciclogermacrene(11.41%), germacrene-D (4.89%), bisabolol11-ol(3.73%) and spathulenol (3.71%) were the major compounds. The essential oil from O. nutans were tested for antibacterial activity using the minimum inhibitory concentracion (MIC) method, Artemia salina method, larvicidal activity in Aedes aegypti, and antioxidant capacity.The antioxidant activity measured by the phosphomolybdenum complex and Prussian blue method had positive results. The minimum inhibitory concentration for the microorganisms tested allowed moderate inhibitionfor Enterococcus faecalis(MIC=500 µg/mL). Artemia salina were toxic to the organisms in the study (LC50= 71,70 μg /mL). The essential oil showed remarkable larvicidal activity potencial (LC50= 250 µg/mL). The present results showed that O. nutans essential oil has potential biological uses

In situ labeling of DNA reveals interindividual variation in nuclear DNA breakdown in hair and may be useful to predict success of forensic genotyping of hair

Hair fibers are formed by keratinocytes of the hair follicle in a process that involves the breakdown of the nucleus including DNA. Accordingly, DNA can be isolated with high yield from the hair bulb which contains living keratinocytes, whereas it is difficult to prepare from the distal portions of hair fibers and from shed hair. Nevertheless, forensic investigations are successful in a fraction of shed hair samples found at crime scenes. Here, we report that interindividual differences in the completeness of DNA removal from hair corneocytes are major determinants of DNA content and success rates of forensic investigations of hair. Distal hair samples were permeabilized with ammonia and incubated with the DNA-specific dye Hoechst 33258 to label DNA in situ. Residual nuclear DNA was visualized under the fluorescence microscope. Hair from some donors did not contain any stainable nuclei, whereas hair of other donors contained a variable number of DNA-positive nuclear remnants. The number of DNA-containing nuclear remnants per millimeter of hair correlated with the amount of DNA that could be extracted and amplified by quantitative PCR. When individual hairs were investigated, only hairs in which DNA could be labeled in situ gave positive results in short tandem repeat typing. This study reveals that the completeness of DNA degradation during cornification of the hair is a polymorphic trait. Furthermore, our results suggest that in situ labeling of DNA in hair may be useful for predicting the probability of success of forensic analysis of nuclear DNA in shed hair