A High Contrast Imaging Survey of SIM Lite Planet Search Targets

With the development of extreme high contrast ground-based adaptive optics instruments and space missions aimed at detecting and characterizing Jupiter- and terrestrial-mass planets, it is critical that each target star be thoroughly vetted to determine whether it is a viable target given both the instrumental design and scientific goals of the program. With this in mind, we have conducted a high contrast imaging survey of mature AFGKM stars with the PALAO/PHARO instrument on the Palomar 200 inch telescope. The survey reached sensitivities sufficient to detect brown dwarf companions at separations of > 50 AU. The results of this survey will be utilized both by future direct imaging projects such as GPI, SPHERE and P1640 and indirect detection missions such as SIM Lite. Out of 84 targets, all but one have no close-in (0.45-1") companions and 64 (76%) have no stars at all within the 25" field-of-view. The sensitivity contrasts in the Ks passband ranged from 4.5 to 10 for this set of observations. These stars were selected as the best nearby targets for habitable planet searches owing to their long-lived habitable zones (> 1 billion years). We report two stars, GJ 454 and GJ 1020, with previously unpublished proper motion companions. In both cases, the companions are stellar in nature and are most likely M dwarfs based on their absolute magnitudes and colors. Based on our mass sensitivities and level of completeness, we can place an upper limit of ~17% on the presence of brown dwarf companions with masses >40 MJ at separations of 1 arcsecond. We also discuss the importance of including statistics on those stars with no detected companions in their field of view for the sake of future companion searches and an overall understanding of the population of low-mass objects around nearby stars.Comment: Accepted to PASP, Figure 7 available upon reques

Effects of Water Quantity on Fish Assemblage Composition in the Upper Cimarron River

Many prairie streams suffer from altered flow regimes as a result of surface and groundwater extraction for irrigation. Changes in flow regimes can alter resident fish assemblage structure and abundance. To determine the effect of water withdrawal on the resident fish assemblage of the upper Cimarron River, I developed and pursued two objectives: 1) quantify the magnitude of stream flow loss in the upper Cimarron River and its effect on the fish assemblage and 2) determine concurrent fish assemblage differences among sites that differ in water quantity. To quantify stream flow loss, I identified a temporal change in stream flow using segmented regression and Indicators of Hydrologic Alteration (IHA) software to compare two periods surrounding the temporal change ("pre" and "post-impact") to determine the magnitude. To determine the effect of stream flow loss on the resident fish assemblage, upper Cimarron River fish collection records from Oklahoma State University, the University of Oklahoma, and the University of Kansas were separated by date into pre and post-impact communities and then compared. To compare concurrent fish assemblage differences among sites with different water quantities, I sampled the Ditch Valley area of the Cimarron River where a diversion of stream flow into an irrigation canal provides four distinct sample sites with different water flows (upstream, canal, diverted river, and downstream). Temperature, salinity, and discharge were measured for each site. Fish were sampled using a seine bi-monthly between May 2012 and December 2012, with an additional sampling in June 2013. A significant change in upper Cimarron River stream flow was detected in 1986, resulting in decreased flows and a change in fish assemblage structure. Post-impact assemblage favored tolerant species able to adapt to reduced water flows. Flow reductions appear to be correlated with of increased groundwater withdrawal for irrigation. Historical drought made comparisons of Ditch Valley fish communities difficult, but general trends were apparent. Species richness was positively correlated with water quantity and fish occurrence in the simplified habitat of the canal was most likely related to entrainment or food resource availability.Natural Resources and Ecology Managemen

Effectiveness measures for geographical information systems (GIS)

Bibliography: pages 85-87.Geographical Information Systems (GIS) often do not meet the expectations of users and management, raising questions and doubts as to their overall success and effectiveness. To date the majority of GIS research has focused on technical issues, and management research has approached GIS effectiveness from a purely cost benefit perspective. This study adopts a holistic, multi-perspective approach to the issue of GIS effectiveness, identifying measures of effectiveness related to the fields of Information Systems (IS), Management Information Systems (MIS) and GIS. It applies these measures using the case study methodology in a small South African local authority, the Ceres Municipality

Slowly cycling Rho kinase-dependent actomyosin cross-bridge slippage explains intrinsic high compliance of detrusor smooth muscle

Biological soft tissues are viscoelastic because they display timeindependent pseudoelasticity and time-dependent viscosity. However, there is evidence that the bladder may also display plasticity, defined as an increase in strain that is unrecoverable unless work is done by the muscle. In the present study, an electronic lever was used to induce controlled changes in stress and strain to determine whether rabbit detrusor smooth muscle (rDSM) is best described as viscoelastic or viscoelastic plastic. Using sequential ramp loading and unloading cycles, stress-strain and stiffness-stress analyses revealed that rDSM displayed reversible viscoelasticity, and that the viscous component was responsible for establishing a high stiffness at low stresses that increased only modestly with increasing stress compared with the large increase produced when the viscosity was absent and only pseudoelasticity governed tissue behavior. The study also revealed that rDSM underwent softening correlating with plastic deformation and creep that was reversed slowly when tissues were incubated in a Ca2+ -containing solution. Together, the data support a model of DSM as a viscoelastic-plastic material, with the plasticity resulting from motor protein activation. This model explains the mechanism of intrinsic bladder compliance as slipping cross bridges, predicts that wall tension is dependent not only on vesicle pressure and radius but also on actomyosin cross-bridge activity, and identifies a novel molecular target for compliance regulation, both physiologically and therapeutically

Structural Verification and Modeling of a Tension Cone Inflatable Aerodynamic Decelerator

Verification analyses were conducted on membrane structures pertaining to a tension cone inflatable aerodynamic decelerator using the analysis code LS-DYNA. The responses of three structures - a cylinder, torus, and tension shell - were compared against linear theory for various loading cases. Stress distribution, buckling behavior, and wrinkling behavior were investigated. In general, agreement between theory and LS-DYNA was very good for all cases investigated. These verification cases exposed the important effects of using a linear elastic liner in membrane structures under compression. Finally, a tension cone wind tunnel test article is modeled in LS-DYNA for which preliminary results are presented. Unlike data from supersonic wind tunnel testing, the segmented tension shell and torus experienced oscillatory behavior when subjected to a steady aerodynamic pressure distribution. This work is presented as a work in progress towards development of a fluid-structures interaction mechanism to investigate aeroelastic behavior of inflatable aerodynamic decelerators

Access to land and other natural resources for local communities in Mozambique: Current examples from Manica Province

Mozambique is still one of the poorest countries in the world. Given that poverty remains overwhelmingly rural in nature, measures to effectively address it should therefore be targeted to the areas where the rural poor live, and should be based on the resources within their control. A programme to achieve these objectives began after the end of the civil war in 1992. This coincided with the government of Mozambique embarking on a more market-oriented rural development model after a period of socialised agriculture. The government realised that, despite being marginalised, rural communities continue to play a crucial role in the development and land management process. Old beliefs that local communities only produce for subsistence and do not invest and respond to market dynamics proved to be inaccurate

Seeing beyond 2020: an economic evaluation of contemporary and emerging strategies for elimination of Trypanosoma brucei gambiense

Background Trypanosoma brucei (T b) gambiense is targeted to reach elimination as a public health problem by 2020 and full elimination by 2030. To achieve these goals, stakeholders need to consider strategies to accelerate elimination. Hence, we aimed to model several options related to current and emerging methods for case detection, treatment, and vector control across settings to assess cost-eff ectiveness and the probability of elimination. Methods Five intervention strategies were modelled over 30 years for low, moderate, and high transmission settings. Model parameters related to costs, effi cacy, and transmission were based on available evidence and parameter estimation. Outcomes included disability-adjusted life-years (DALYs), costs, and long-term prevalence. Sensitivity analyses were done to calculate the uncertainty of the results. Findings To reach elimination targets for 2020 across all settings, approaches combining case detection, treatment, and vector control would be most eff ective. Elimination in high and moderate transmission areas was probable and costeff ective when strategies included vector control and novel methods, with incremental cost-eff ectiveness ratios (ICERs) ranging from US$400 to$1500 per DALY averted. In low transmission areas, approaches including the newest interventions alone or in combination with tiny targets (vector control) were cost-eff ective, with ICERs of $200 or$1800 per DALY averted, respectively, but only strategies including vector control were likely to lead to elimination. Results of sensitivity analyses showed that allowing for biennial surveillance, reducing vector control maintenance costs, or variations of active surveillance coverage could also be cost-eff ective options for elimination, depending on the setting. Interpretation Although various strategies might lead to elimination of T b gambiense, cost-eff ective approaches will include adoption of emerging technologies and, in some settings, increased surveillance or implementation of vector control

A new acquisition model for the next disaster: overcoming disaster federalism issues through effective utilization of the Strategic National Stockpile

Using primary data collected from interviews with federal and state government officials and secondary data related to PPE distribution and state healthcare statistics, we discovered evidence that the use of the Strategic National Stockpile (SNS) to distribute personal protective equipment to state and local agencies in need during the height of COVID-19 was indeed poorly designed to cope with the COVID-19 emergency, leaving many states with shortages of badly needed medical supplies. As a result, many states struggled to organize an uncoordinated procurement response – which we suggest is due to federalism issues. To overcome federalism challenges and increase future disaster preparedness, we recommend four necessary reforms to the SNS that include 1) the incorporation of uncompensated industry experts into SNS administration, 2) the provision of an emergency production board for times of crisis, 3) elevated political leadership for the SNS, 4) improvement of federal-state supply chain governance

Expanding a Supercomputer Facility Using Modular Data Center Technology

With the expansion of high-end computing resources needed to support NASA's increasing demands for physics-based simulations, the facility housing Pleiades-the agency's largest supercomputer-recently reached its power and cooling capacity. In response, the NASA Advanced Supercomputing Division at Ames Research Center undertook a prototype project that resulted in a new facility based on modular data center technology. The facility, a ~1000 square-foot module on a concrete pad with room for 16-18 compute racks, was completed in fall 2016 and an SGI computer system, named Electra, was deployed there in early 2017. Cooling is performed via an evaporative system built into the module, and preliminary experience shows a Power Usage Effectiveness (PUE) of ~1.03. Electra achieved over a petaflop on the LINPACK benchmark, sufficient to rank number 96 on the November 2016 TOP500 list. The system consists of 1,152 InfiniBand-connected Intel Xeon Broadwell-based nodes. Its users access their files on a facility wide file system shared by all compute assets via Mellanox MetroX InfiniBand extenders, which connect the Electra fabric to Lustre routers InfiniBand fabric over fiber-optic links about 300 meters long. The prototype has exceeded expectations and is serving as a blueprint for future expansions.