Twenty-first semiannual report to Congress, 1 January - 30 June 1969

Manned space flights, satellite observations, space sciences, and air traffic control - NASA report to Congress for 1 Jan. to 30 June 196

Geometrical multilayers: coercivity in magnetic 3-D nanostructures

Electrodeposition of magnetic metals through self-assembly templates from polystyrene spheres is used for fabrication of magnetic nanostructures with 3-D architectures. These arrays demonstrate unusual properties including an oscillatory dependence of the coercive field on film thickness. Numerical simulations reveal that the ratio between the array period and the hole diameter in anti-dot array is a crucial parameter giving rise to qualitatively distinct magnetization reversal regimes

Self-assembly routes towards creating superconducting and magnetic arrays

Using self-assembly from colloidal suspensions of polystyrene latex spheres we prepared well-ordered templates. By electrochemical deposition of magnetic and superconducting metals in the pores of such templates highly ordered magnetic and superconducting anti-dot nano-structures with 3D architectures were created. Further developments of this template preparation method allow us to obtain dot arrays and even more complicated structures. In magnetic anti-dot arrays we observe a large increase in coercive field produced by nanoscale (50–1000nm) holes. We also find the coercive field to demonstrate an oscillatory dependence on film thickness. In magnetic dot arrays we have explored the genesis of 3D magnetic vortices and determined the critical dot size. Superconducting Pb anti-dot arrays show pronounced Little-Parks oscillations in Tc and matching effects in magnetization and magnetic susceptibility. The spherical shape of the holes results in significantly reduced pinning strength as compared to standard lithographic samples. Our results demonstrate that self-assembly template methods are emerging as a viable, low cost route to prepare sub-micron structures

Determination of semi-arid landscape endmembers and seasonal trends using convex geometry spectral unmixing techniques

Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) data were acquired during three consecutive growing seasons (26 September 1989, 22 March 1990, and 7 August 1990) over an area of the High Plains east of Greeley, Colorado (40 deg 20 min N and 104 deg 16 min W). A repeat visit to assess vegetation at its peak growth was flown on 6 June 1993. This region contains extensive eolian deposits in the form of stabilized dune complexes (small scale parabolic dunes superimposed on large scale longitudinal and parabolic dunes). Due to the dunes' large scale (2-10 km) and low relief (1-5 m), the scaling and morphological relationships that contribute to the evolution of this landscape are nearly impossible to understand without the use of remote sensing. Additionally, this area and regions similarly situated could be the first to experience the effects caused by global climate change. During the past 10,000 years there were at least four periods of extensive sand activity due to climate change, followed by periods of landscape stability, as shown in the stratigraphic record of this area

Modelling the effectiveness of grass buffer strips in managing muddy floods under a changing climate

Muddy floods occur when rainfall generates runoff on agricultural land, detaching and transporting sediment into the surrounding natural and built environment. In the Belgian Loess Belt, muddy floods occur regularly and lead to considerable economic costs associated with damage to property and infrastructure. Mitigation measures designed to manage the problem have been tested in a pilot area within Flanders and were found to be cost-effective within three years. This study assesses whether these mitigation measures will remain effective under a changing climate. To test this, the Water Erosion Prediction Project (WEPP) model was used to examine muddy flooding diagnostics (precipitation, runoff, soil loss and sediment yield) for a case study hillslope in Flanders where grass buffer strips are currently used as a mitigation measure. The model was run for present day conditions and then under 33 future site-specific climate scenarios. These future scenarios were generated from three earth system models driven by four representative concentration pathways and downscaled using quantile mapping and the weather generator CLIGEN. Results reveal that under the majority of future scenarios, muddy flooding diagnostics are projected to increase, mostly as a consequence of large scale precipitation events rather than mean changes. The magnitude of muddy flood events for a given return period is also generally projected to increase. These findings indicate that present day mitigation measures may have a reduced capacity to manage muddy flooding given the changes imposed by a warming climate with an enhanced hydrological cycle. Revisions to the design of existing mitigation measures within existing policy frameworks are considered the most effective way to account for the impacts of climate change in future mitigation planni

Changes to adult dog social behaviour during and after COVID-19 lockdowns in England: a qualitative analysis of owner perception

Reports suggest that dogs have experienced more quality time with their owners and have exhibited less separation-related behaviour during COVID-19. This study aims to define and explore the changes in the social behaviour of adult dogs, identify any perceived short- and long-term effects and identify the implications that future events may have due to the implementation and withdrawal of COVID-19 restrictions. Owners of dogs aged between 3 and 6 years living in England were recruited for semi-structured interviews about their dogs’ social behaviours before, during and after lockdown. Interviews were transcribed and thematic analysis was used to identify key themes. Fifteen owners of eighteen dogs were interviewed in December 2021 to January 2022. All owners interviewed noticed a change in behaviour either during or following the COVID-19 lockdowns. Many owners found that fear-related and aggressive behaviours increased, particularly after lockdown restrictions had been lifted. There is a risk to human and animal safety if fear-related behaviours are not properly managed and there is a danger to dog welfare through relinquishment as owners struggle to cope with problematic behaviours. An increase in the duration of walks is comparable to other studies; however, this study found that many owners continued to walk their dogs more than restrictions allowed. Reliable information or behavioural support by qualified professionals may be needed to aid owners in mitigating the impacts of the COVID-19 pandemic. Behaviour modification plans or information could include positive techniques such as desensitisation and counterconditioning. More widely, owners should be prepared for any future behavioural changes due to unpredictable events which may alter the dog–owner dynamic. Results can be adapted to the increase in at-home working following the pandemic or other novel experiences and changes of routine such as retirement, job change or relocation. More awareness of the long-term implications of the COVID-19 pandemic is needed to prepare dog behaviour professionals for future owner concerns

EFFECTS OF RELEASE TECHNIQUES ON PARENT-REARED WHOOPING CRANES IN THE EASTERN MIGRATORY POPULATION

Reintroduction of an Eastern Migratory Population (EMP) of whooping cranes (Grus americana) in the United States by release of captive-reared individuals began in 2001. As of 2020, the EMP has approximately 21 breeding pairs and has had limited recruitment of wild-hatched individuals, thus captive-reared juveniles continue to be released into breeding areas in Wisconsin to maintain the population. We investigated the effects of release techniques on survival, behavior, site fidelity, and conspecific associations of 42 captive-parent-reared whooping cranes released during 2013-2019 into the EMP. Individuals were monitored intensively post-release, then as a part of a long-term monitoring program, locational, behavioral, and habitat use data were collected and analyzed. Most cranes roosted in water post-release; however, we documented 4 parent-reared cranes roosting on dry land. Most cranes eventually associated with other whooping cranes; however, juveniles released near single adult cranes were less likely to associate with other whooping cranes during their first migration or winter than juveniles released near other types of whooping crane pairs or groups. Parent-reared and costume-reared whooping cranes had similar rates of survival 1 year post-release (69.0% and 64.4%, respectively). The highest risk of mortality was within the first 100 days post-release, and the leading known causes of death were predation and impact trauma due to powerline or vehicle collisions. Both costume- and parent-reared cranes had strong fidelity to release sites. We advise releasing parent-reared cranes near pairs or groups of whooping cranes and taking measures to reduce the risk of mortality during the immediate period after release (e.g., predator aversion training, marking powerlines)

Shape-induced anisotropy in antidot arrays from self-assembled templates

Using self-assembly of polystyrene spheres, well-ordered templates have been prepared on glass and silicon substrates. Strong guiding of self-assembly is obtained on photolithographically structured silicon substrates. Magnetic antidot arrays with three-dimensional architecture have been prepared by electrodeposition in the pores of these templates. The shape anisotropy demonstrates a crucial impact on magnetization reversal processes