Rover technology for manned Mars missions

A set of roving vehicle design requirements were postulated, corresponding to an idealized Mars transport vehicle operational scenario which could serve as a reference for a manned Mars mission. The ability of conventional vehicles to satisfy these requirements were examined. The study indicated that no conventional vehicle could satisfy all of the requirements, as the vehicles are presently configured. Consequently, the requirements have to either be relaxed and/or an alternative, less conventional vehicle design will have to be developed. A possible unconventional vehicle design which has received considerable attention for DARPA and the Army is the walker vehicle. The design issues associated with this vehicle are presented, along with a comparison of the performance capabilities of this technology vs. conventional vehicle technology

The VISTA spacecraft: Advantages of ICF (Inertial Confinement Fusion) for interplanetary fusions propulsion applications

Inertial Confinement Fusion (ICF) is an attractive engine power source for interplanetary manned spacecraft, especially for near-term missions requiring minimum flight duration, because ICF has inherent high power-to-mass ratios and high specific impulses. We have developed a new vehicle concept called VISTA that uses ICF and is capable of round-trip manned missions to Mars in 100 days using A.D. 2020 technology. We describe VISTA's engine operation, discuss associated plasma issues, and describe the advantages of DT fuel for near-term applications. Although ICF is potentially superior to non-fusion technologies for near-term interplanetary transport, the performance capabilities of VISTA cannot be meaningfully compared with those of magnetic-fusion systems because of the lack of a comparable study of the magnetic-fusion systems. We urge that such a study be conducted

G91-1009 Getting Started in Ecofarming: Growing the Winter Wheat Crop

Cultural practices can improve the weed competitiveness of winter wheat in an ecofallow program, thus increasing the effectiveness of herbicides. Ecofarming is a popular conservation tillage practice used in Nebraska areas where winter wheat is produced. It requires a high degree of management, but the rewards through higher crop yields and erosion protection are worth the effort. In Nebraska the winter wheat-fallow rotation is the common rotation used in areas of less than 17 inches of rainfall, while in areas that receive 17 to 22 inches the winter wheat-corn or sorghum fallow rotation is most common. In 1988, 41 percent of the available wheat stubble fields in west central and southwest Nebraska and 11 percent in the Panhandle were sprayed with a herbicide after wheat harvest. In 1986 a field survey was taken one to two months after herbicides were applied after winter wheat harvest. Results indicated that many cultural practices greatly influenced weed control in the winter wheat stubble. The purpose of this NebGuide is to explain how some of these cultural practices can be used by farmers to improve the weed competitiveness of their winter wheat. Hence, when herbicides are used their effectiveness is increased

Dust in Brown Dwarfs IV. Dust formation and driven turbulence on mesoscopic scales

Dust formation in brown dwarf atmospheres is studied by utilising a model for driven turbulence in the mesoscopic scale regime. We apply a pseudo-spectral method where waves are created and superimposed within a limited wavenumber interval. The turbulent kinetic energy distribution follows the Kolmogoroff spectrum which is assumed to be the most likely value. Such superimposed, stochastic waves may occur in a convectively active environment. They cause nucleation fronts and nucleation events and thereby initiate the dust formation process which continues until all condensible material is consumed. Small disturbances are found to have a large impact on the dust forming system. An initially dust-hostile region, which may originally be optically thin, becomes optically thick in a patchy way showing considerable variations in the dust properties during the formation process. The dust appears in lanes and curls as a result of the interaction with waves, i.e. turbulence, which form larger and larger structures with time. Aiming on a physical understanding of the variability of brown dwarfs, related to structure formation in substellar atmospheres, we work out first necessary criteria for small-scale closure models to be applied in macroscopic simulations of dust forming astrophysical systems.Comment: A&A accepted, 20 page

GP and nurses' perceptions of how after hours care for people receiving palliative care at home could be improved: a mixed methods study

<p>Abstract</p> <p>Background</p> <p>Primary health care providers play a dominant role in the provision of palliative care (PC) in Australia but many gaps in after hours service remain. In some rural areas only 19% of people receiving palliative care achieve their goal of dying at home. This study, which builds on an earlier qualitative phase of the project, investigates the gaps in care from the perspective of general practitioners (GPs) and PC nurses.</p> <p>Methods</p> <p>Questionnaires, developed from the outcomes of the earlier phase, and containing both structured and open ended questions, were distributed through Divisions of General Practice (1 urban, 1 rural, 1 mixed) to GPs (n = 524) and through a special interest group to palliative care nurses (n = 122) in both rural and urban areas.</p> <p>Results</p> <p>Questionnaires were returned by 114 GPs (22%) and 52 nurses (43%). The majority of GPs were associated with a practice which provided some after hours services but PC was not a strong focus for most. This was reflected in low levels of PC training, limited awareness of the existence of after hours triage services in their area, and of the availability of Enhanced Primary Care (EPC) Medicare items for care planning for palliative patients. However, more than half of both nurses and GPs were aware of accessible PC resources.</p> <p>Factors such as poor communication and limited availability of after hours services were identified the as most likely to impact negatively on service provision. Strategies considered most likely to improve after hours services were individual patient protocols, palliative care trained respite carers and regular multidisciplinary meetings that included the GP.</p> <p>Conclusion</p> <p>While some of the identified gaps can only be met by long term funding and policy change, educational tools for use in training programs in PC for health professionals, which focus on the utilisation of EPC Medicare items in palliative care planning, the development of advance care plans and good communication between members of multidisciplinary teams, which include the GP, may enhance after hours service provision for patients receiving palliative care at home. The role of locums in after PC is an area for further research</p

Examination of the Relationship of Dairy Product Consumption and Dietary Calcium with Body Mass Index Percentile in Children

Aim: The purpose of this study was to assess the relationships of dairy product and calcium intake with BMI percentile in children. Methods: In this cross-sectional analysis, the relationships of dairy product (cup equivalents/day) and dietary calcium (mg/day) (measured by 24 hour recall) consumption with BMI percentile [derived from Centers for Disease Control and Prevention (CDC) sex-specific BMI-for-age growth charts] were assessed in 101 healthy U.S. children (ages 8-13). Results: Subject characteristics included (mean + SD): dairy product consumption (2.8 + 1.4 cup equivalents/day), dietary calcium (1039.4 + 431.4 mg/day), and BMI percentile (70.1 + 29.7). Dairy product intake and dietary calcium were inversely related to BMI percentile (p= 0.005). In subjects &lt;85th BMI percentile (n= 50 normal weight and n= 3 underweight), there was an inverse association of dairy product intake with BMI percentile (p= 0.001) and calcium intake with BMI percentile (p&lt; 0.001). However, no association of dairy product consumption or calcium intake with BMI percentile was observed in overweight (85th percentile ≤ BMI &lt; 95th percentile, n= 19) or obese subjects (BMI &gt; 95th percentile, n= 29). Removal of underweight subjects from the analysis only minimally impacted the results. Differences in dietary intake (MyPyramid food groups, calories, macronutrients, micronutrients) among normal, overweight, and obese subgroups were examined. No significant differences were detected between groups, and removing underweight subjects did not change the findings. Conclusions: These results provide the basis for further investigation into a potential role of dairy and calcium in achieving a healthy body weight in children

Evaluating the Likelihood of Tree Failure in Naples, Florida (United States) Following Hurricane Irma

Trees in residential landscapes provide many benefits, but can injure persons and damage property when they fail. In hurricane-prone regions like Florida, USA, the regular occurrence of hurricanes has provided an opportunity to assess factors that influence the likelihood of wind-induced tree failure and develop species failure profiles. We assessed open-grown trees in Naples, Florida, following the passage of Hurricane Irma in September 2017 to determine the effect of relevant factors on the degree of damage sustained by individual trees. Of 4034 assessed individuals (n = 15 species), 74% sustained no damage, 4% sustained only minor damage (i.e., minimal corrective pruning needed), 6% sustained significant damage (i.e., major corrective pruning needed), and 15% were whole-tree failures (i.e., overturned trees or trees requiring removal). The proportion of individuals in each damage category varied among species, stem diameter at 1.4 m above ground, and the presence of utility lines, which was a proxy for maintenance. We compared our results with the findings of seven previous hurricanes in the region to explore species’ resilience in hurricanes

Speed impairs attending on the left: comparing attentional asymmetries for neglect patients in speeded and unspeeded cueing tasks

Visuospatial neglect after stroke is often characterized by a disengage deficit on a cued orienting task, in which individuals are disproportionately slower to respond to targets presented on the contralesional side of space following an ispilesional cue as compared to the reverse. The purpose of this study was to investigate the generality of the finding of a disengage deficit on another measure of cued attention, the temporal order judgment (TOJ) task, that does not depend upon speeded manual responses. Individuals with right hemisphere stroke with and without spatial neglect and older healthy controls (OHC) were tested with both a speeded RT cueing task and an unspeeded TOJ-with-cuing task. All stroke patients evidenced a disengage deficit on the speeded RT cueing task, although the size and direction of the bias was not associated with the severity of neglect. In contrast, few neglect patients showed a disengage deficit on the TOJ task. This discrepancy suggests that the disengage deficit may be related to task demands, rather than solely due to impaired attentional mechanisms per se. Further, the results of our study show that the disengage deficit is neither necessary nor sufficient for neglect to manifest

G92-1071 Ridge Plant Systems: Weed Control

Advantages and disadvantages of the ridge plant system, weed control before and at planting and economics of the system are discussed. Ridge planting combines tillage and herbicides to achieve improved weed control in row crops. Crop seed is planted into ridges formed during cultivation and/or ditching of the previous crop. In ridge planting, the planter follows the old row and ridge clearing sweeps or disks move the surface soil, residue and much of the weed seed out of the row. Weed seeds are deposited between the rows where, upon germination, they can be controlled with cultivation. Two cultivations are generally used for weed control. The first cultivation loosens the soil and the second rebuilds the ridge. The ridge plant system is well suited to furrow-irrigationd crops. It also works well with dryland crops or those under center pivot irrigation. On furrow irrigationd land, corn or sorghum stalks may need to be shredded to assist in decomposition and hence irrigation because crop residue slows water advance in the furrow. Slowing the water may be a benefit, however, on soils which have a low water intake rate. With center pivot and dryland acres the need for shredding depends on how much residue the cultivator can handle

G92-1071 Ridge Plant Systems: Weed Control

Advantages and disadvantages of the ridge plant system, weed control before and at planting and economics of the system are discussed. Ridge planting combines tillage and herbicides to achieve improved weed control in row crops. Crop seed is planted into ridges formed during cultivation and/or ditching of the previous crop. In ridge planting, the planter follows the old row and ridge clearing sweeps or disks move the surface soil, residue and much of the weed seed out of the row. Weed seeds are deposited between the rows where, upon germination, they can be controlled with cultivation. Two cultivations are generally used for weed control. The first cultivation loosens the soil and the second rebuilds the ridge. The ridge plant system is well suited to furrow-irrigationd crops. It also works well with dryland crops or those under center pivot irrigation. On furrow irrigationd land, corn or sorghum stalks may need to be shredded to assist in decomposition and hence irrigation because crop residue slows water advance in the furrow. Slowing the water may be a benefit, however, on soils which have a low water intake rate. With center pivot and dryland acres the need for shredding depends on how much residue the cultivator can handle