The Impact of Welfare Programs on Poverty Rates: Evidence from the American States

There is spirited debate between those who maintain that public assistance to the poor decreases poverty by raising their incomes (an income enhancement effect) and those who contend that welfare increases poverty by discouraging the poor from working (a work disincentive effect). Extant studies have been inconclusive because they have focused on the effect of welfare benefits on the poverty rate, but have not employed designs that allow researchers to sort out distinct income enhancement and work disincentive effects. We develop a model of poverty rates in the American states that permits estimation of these distinct effects ñ based on state-level time-series data observed annually for the years 1960-90 - and we find that welfare had both effects during our period of analysis. We also calculate the net impact on the poverty rate of an increase in welfare benefits (taking into account both income enhancement and work disincentives), and we conclude that it has varied across states and time. In general, however, the ability of marginal increases in welfare spending to reduce the poverty rate by enhancing incomes has declined since the 1970s

THE ECONOMIC THRESHOLD FOR GRASSHOPPER CONTROL ON PUBLIC RANGELANDS

The U.S. Department of Agriculture's Animal and Plant Health Inspection Service (APHIS) is responsible for controlling grasshopper populations on public rangelands. Under current guidelines, control of grasshoppers on rangeland should occur if grasshopper densities are at least eight per square yard. This article evaluates the concept of an economic threshold relative to the value of forage saved from destruction during a grasshopper outbreak. It is shown that financial justification for treating grasshopper outbreaks depends upon grasshopper density, rangeland productivity, climate factors, livestock cost and return relationships, and the efficacy of treatment options.Resource /Energy Economics and Policy, Land Economics/Use,

Experimental Evaluation of High Performance Integrated Heat Pump

Integrated heat pump (IHP) technology provides significant potential for energy savings and comfort improvement for residential buildings. In this study, we evaluate the performance of a high performance IHP that provides space heating, cooling, and water heating services. Experiments were conducted according to the ASHRAE Standard 206-2013 where 24 test conditions were identified in order to evaluate the IHP performance indices. An 8-in by 8-in Air Monitor Fan Evaluator is used to measure the volumetric flowrate of air discharged from the air handler unit (AHU) in order to evaluate the airside performance. Empirical curve fits of the unit’s compressor maps are used in conjunction with saturated condensing and evaporating refrigerant conditions to deduce the refrigerant mass flowrate, which, in turn is used to evaluate the refrigerant-side performance. Heat pump (compressor, fans, and controls) and water pump power were measured separately per requirements of Standard 206. The system was charged per the system manufacturer’s specifications. System test results are presented for each operating mode along with overall IHP performance metrics according to ASHRAE standard 206-2013. The paper ends with discussion on system operation and impact on typical energy consumption in residential buildings

BMQ

BMQ: Boston Medical Quarterly was published from 1950-1966 by the Boston University School of Medicine and the Massachusetts Memorial Hospitals

Clinical trialist perspectives on the ethics of adaptive clinical trials: a mixed-methods analysis

Abstract Background In an adaptive clinical trial (ACT), key trial characteristics may be altered during the course of the trial according to predefined rules in response to information that accumulates within the trial itself. In addition to having distinguishing scientific features, adaptive trials also may involve ethical considerations that differ from more traditional randomized trials. Better understanding of clinical trial experts’ views about the ethical aspects of adaptive designs could assist those planning ACTs. Our aim was to elucidate the opinions of clinical trial experts regarding their beliefs about ethical aspects of ACTs. Methods We used a convergent, mixed-methods design employing a 22-item ACTs beliefs survey with visual analog scales and open-ended questions and mini-focus groups. We developed a coding scheme to conduct thematic searches of textual data, depicted responses to visual analog scales on box-plot diagrams, and integrated findings thematically. Fifty-three clinical trial experts from four constituent groups participated: academic biostatisticians (n = 5); consultant biostatisticians (n = 6); academic clinicians (n = 22); and other stakeholders including patient advocacy, National Institutes of Health, and U.S. Food and Drug Administration representatives (n = 20). Results The respondents recognized potential ethical benefits of ACTs, including a higher probability of receiving an effective intervention for participants, optimizing resource utilization, and accelerating treatment discovery. Ethical challenges voiced include developing procedures so trial participants can make informed decisions about taking part in ACTs and plausible, though unlikely risks of research personnel altering enrollment patterns. Conclusions Clinical trial experts recognize ethical advantages but also pose potential ethical challenges of ACTs. The four constituencies differ in their weighing of ACT ethical considerations based on their professional vantage points. These data suggest further discussion about the ethics of ACTs is needed to facilitate ACT planning, design and conduct, and ultimately better allow planners to weigh ethical implications of competing trial designs.http://deepblue.lib.umich.edu/bitstream/2027.42/111302/1/12910_2015_Article_22.pd

Shockwave/Boundary-Layer Interaction Studies Performed in the NASA Langley 20-Inch Mach 6 Air Tunnel

This paper highlights results from a collaborative study performed by The University of Tennessee Space Institute (UTSI) and NASA Langley Research Center on the Shockwave/Boundary-Layer Interaction (SWBLI) generated by a cylindrical protuberance on a flat plate in a Mach 6 flow. The study was performed in the 20-Inch Mach 6 Air Tunnel at NASA Langley Research Center and consisted of two separate entries. In the first entry, simultaneous high-speed schlieren and high-speed pressure-sensitive paint (PSP) imaging which was performed for the first time in the 20-Inch Mach 6 facility at NASA Langley were performed as well as simultaneous high-speed schlieren and oil-flow imaging. In the second entry, the model configuration was modified to increase the size of the interaction region. High-speed schlieren and infrared thermography (IR) surface imaging were performed in this second entry. The goal of these tests was to characterize the SBLI in the presence of a laminar, transitional, and turbulent boundary layer using high-speed optical imaging techniques. AoA = sting angle-of-attack () dcylinder = cylinder diameter (mm) dtrip = cylindrical tripping element diameter (mm) shock = shock stand-off distance (mm) hcylinder = cylinder height (mm) htrip = cylindrical tripping element height (mm) HSS = high-speed schlieren M = freestream Mach number PSP = pressure-sensitive paint Re = freestream unit Reynolds number (m-1) SWBLI = shockwave/boundary-layer interaction plate = model plate angle () Introduction his paper highlights two experimental entries performed in the 20-Inch Mach 6 Air Blowdown Tunnel at NASA Langley Research Center in collaboration with The University of Tennessee Space Institute (UTSI). The purpose of these entries was to characterize the dynamic shockwave/boundary-layer interaction (SWBLI) between a vertical cylinder on a flat plate and laminar, transitional (XSWBLI), and turbulent (SWTBLI) boundary layers with a freestream Mach number of 6 using non-intrusive optical diagnostics. Experiments performed by Murphree et al.1,2 were among the first to specifically characterize XSWBLI induced by a vertical cylinder on a flat plate geometry using several optical measurement techniques. Recent optical studies of XSWBLI phenomenon have been performed by UTSI at Mach 2 in their low-enthalpy blow wind tunnel3-8 and by Texas A&M University and UTSI at Mach numbers of 6 and 7 in their Adjustable Contour Expansion wind tunnel.9 The experiments described in this paper were intended to complement previous studies by expanding the freestream unit Reynolds number range, Re, over which the XSWBLI phenomena has been observed. Additionally these experiments, made possible under NASAs new facility funding model under the Aeronautics Evaluation and Test Capabilities (AETC) project, promoted collaboration between university and NASA researchers. The initial entry in the 20-Inch Mach 6 Air Tunnel at NASA Langley occurred in December of 2016. Originally, testing was to occur in November of 2016 in the 31-Inch Mach 10 Air Tunnel at NASA Langley. This facility was chosen so that the XSWBLI phenomenon could be observed at much higher Mach numbers than had previously been attempted in ground test experiments. The model selected for this experiment, a 10 half-angle wedge with a sharp leading edge (described in detail in section II.B), had previously been used by Danehy et al. [10] for boundary layer transition studies using the nitric oxide planar laser-induced fluorescence (NO PLIF) flow visualization technique. In that work, it was determined that transition could be induced downstream of a single htrip = 1-mm tall, dtrip = 4-mm diameter cylindrical tripping element and that the streamwise location of the transition could be changed for a single Re by changing the model angle-of-attack (AoA) (see Fig. A3 in Ref. [10] for more details). Based on the findings of that work, a decision was made to use the wedge model with the cylindrical tripping element to trip the boundary layer flow ahead of a cylindrical protuberance in order to achieve a XSWBLI. Unfortunately, the 31-Inch Mach 10 facility had been taken offline for repairs in October of 2016 and a decision was made to move the test to the 20-Inch Mach 6 facility. Since the behavior of the boundary layer with the chosen model configuration had not been studied before in that facility and the available test time was limited, the entry was considered to be exploratory and was used to collect spatially-resolved and time-resolved flow and surface visualization data that would be used to inform a second entry. Test techniques included simultaneous high-speed schlieren (HSS) captured at 160 kHz and high-speed pressure sensitive paint captured at 10 kHz as well as oil flow visualization, captured at 750 Hz. The second entry in the 20-Inch Mach 6 facility occurred in June and July of 2017. In this follow-on test, modifications to the wind tunnel model were made based on observations made during the first entry and included removing the cylindrical tripping element, increasing the size of the cylinder used to induce the SWBLI to increase the size of the interaction while simultaneously improving spatial resolution, and using a swept ramp array, similar to that described in Ref. [11], to trip the flow to turbulence. Simultaneous HSS (captured at 140 kHz, 100 kHz, and 40 kHz) and conventional IR thermography (captured at 30 Hz) imaging were performed simultaneously in this follow-on entry. This paper is intended to serve as a summary of the work performed during these two entries, to detail lessons learned from each entry, and to highlight some of the datasets acquired. Details on the experimental setup, model configuration, and techniques used are provided. Papers providing a more rigorous analysis of data acquired during the second entry, including statistical, spectral, and modal decomposition methods, can be found in Refs. [12,13]. An entry examining XSWBLI in the 31-Inch Mach 10 Blowdown Wind Tunnel facility is currently planned for mid-to-late calendar year 2019, pending the success of facility repairs. The work performed and described in this paper and the upcoming entry in the 31-Inch Mach 10 facility at NASA Langley have been made possible by NASAs new facility funding model under the Aeronautics Evaluation and Test Capabilities (AETC) project. Wind Tunnel Facility All experiments discussed in this paper were performed in the 20-Inch Mach 6 Air Tunnel at NASA Langley Research Center. Specific details pertaining to this facility can be found in Refs. [14,15], with only a brief description of the facility provided here. For both entries, the nominal freestream unit Reynolds number was varied between 1.8106 m-1 (0.5106 ft-1) and 26.3106 m-1 (8106 ft-1). The nominal stagnation pressure was varied between 0.21 MPa and 3.33 MPa and the nominal stagnation temperature was varied between 480 K and 520 K to achieve the desired Re condition. For all runs, the nominal freestream Mach number was 6. The nearly square test section is 520.7-mm (20.5-inches) wide by 508-mm (20-inches) high. Two 431.8-mm (17-inch) diameter windows made of Corning 7940, Grade 5F schlieren-quality glass serve as the side walls of the tunnel and provide optical access for the high-speed schlieren measurements. A rectangular window made of the same material as the side windows served as the top wall of the test section and provided optical access for the high-speed PSP and oil flow measurements. For the second entry, this top window was replaced with a Zinc Selenide (ZnSe) window with an anti-reflection coating capable of passing IR wavelengths between 8m and 12m with greater than 98% transmittance. The model was sting supported by a strut attached to a hydraulic system that allows for the model pitch angle to be adjusted between -5 to +55. For the first entry, an initial pitch/pause sweep of the model AoA was performed to observe the resulting SWBLI. Ultimately, however, the sting pitch angle for this entry was fixed at +10.0 so that the angle of the top surface of the wedge relative to the streamwise axis of the tunnel (referred to herein as the plate angle, plate), was plate = 0. For the second entry, plate = 0 and plate = -13.25 were initially tested with the swept ramp array (discussed in the following section) to determine which orientation produced conditions most favorable for XSWBLI to occur based on the heating signatures observed over the top surface of the model in the IR thermography images. Based on these initial tests, plate = -13.25 was set for the remainder of the runs in the second entry. For both entries, any model changes were performed in a housing located beneath the closed test section. Prior to performing a run of the tunnel, the housing was sealed and the tunnel started. Once the appropriate freestream conditions were achieved, the model was injected into the test section using a hydraulic injection system. B. Model Geometry For all runs, a 10 half-angle (20 full-angle) wedge model with a sharp leading edge was used. The model is described in detail in Refs. [10,16]. The top surface of the sharp leading edge of the model extended 47.8 mm from its upstream-most edge to a junction with the upstream edge of a stainless steel top plate that then extended an (a) (c) (b) Fig. 1 (a) Schematic of top surface of wedge model with gas seeding insert, (b) perspective view of the model in the 20-Inch Mach 6 tunnel with centerline pressure orifices on sharp leading edge, and (c) a perspective view of the model with stainless steel (top) and SLA middle insert (bottom) during the first entry. Flow occurs from left to right

Red-and-Black with Unknown Win Probability

1 online resource (PDF, 12 pages

Effects of deep sedation or general anesthesia on cardiac function in mice undergoing cardiovascular magnetic resonance

<p>Abstract</p> <p>Background</p> <p>Genetically engineered mouse models of human cardiovascular disease provide an opportunity to understand critical pathophysiological mechanisms. Cardiovascular magnetic resonance (CMR) provides precise reproducible assessment of cardiac structure and function, but, in contrast to echocardiography, requires that the animal be immobilized during image acquisition. General anesthetic regimens yield satisfactory images, but have the potential to significantly perturb cardiac function. The purpose of this study was to assess the effects of general anesthesia and a new deep sedation regimen, respectively, on cardiac function in mice as determined by CMR, and to compare them to results obtained in mildly sedated conscious mice by echocardiography.</p> <p>Results</p> <p>In 6 mildly sedated normal conscious mice assessed by echo, heart rate was 615 ± 25 min^-1(mean ± SE) and left ventricular ejection fraction (LVEF) was 0.94 ± 0.01. In the CMR studies of normal mice, heart rate was slightly lower during deep sedation with morphine/midazolam (583 ± 30 min^-1), but the difference was not statistically significant. General anesthesia with 1% inhaled isoflurane significantly depressed heart rate (468 ± 7 min^-1, p < 0.05 vs. conscious sedation). In 6 additional mice with ischemic LV failure, trends in heart rate were similar, but not statistically significant. In normal mice, deep sedation depressed LVEF (0.79 ± 0.04, p < 0.05 compared to light sedation), but to a significantly lesser extent than general anesthesia (0.60 ± 0.04, p < 0.05 vs. deep sedation).</p> <p>In mice with ischemic LV failure, ejection fraction measurements were comparable when performed during light sedation, deep sedation, and general anesthesia, respectively. Contrast-to-noise ratios were similar during deep sedation and during general anesthesia, indicating comparable image quality. Left ventricular mass measurements made by CMR during deep sedation were nearly identical to those made during general anesthesia (r²= 0.99, mean absolute difference < 4%), indicating equivalent quantitative accuracy obtained with the two methods. The imaging procedures were well-tolerated in all mice.</p> <p>Conclusion</p> <p>In mice with normal cardiac function, CMR during deep sedation causes significantly less depression of heart rate and ejection fraction than imaging during general anesthesia with isoflurane. In mice with heart failure, the sedation/anesthesia regimen had no clear impact on cardiac function. Deep sedation and general anesthesia produced CMR with comparable image quality and quantitative accuracy.</p

Striatal dopamine synthesis and cognitive flexibility differ between hormonal contraceptive users and nonusers

In rodents and nonhuman primates, sex hormones are powerful modulators of dopamine (DA) neurotransmission. Yet less is known about hormonal regulation of the DA system in the human brain. Using positron emission tomography (PET), we address this gap by comparing hormonal contraceptive users and nonusers across multiple aspects of DA function: DA synthesis capacity via the PET radioligand 6-[18F]fluoro-m-tyrosine ([18F]FMT), baseline D2/3 receptor binding potential using [11C]raclopride, and DA release using methylphenidate-paired [11C]raclopride. Participants consisted of 36 healthy women (n = 15 hormonal contraceptive users; n = 21 naturally cycling/non users of hormonal contraception), and men (n = 20) as a comparison group. A behavioral index of cognitive flexibility was assessed prior to PET imaging. Hormonal contraceptive users exhibited greater DA synthesis capacity than NC participants, particularly in dorsal caudate, and greater cognitive flexibility. Furthermore, across individuals, the magnitude of striatal DA synthesis capacity was associated with cognitive flexibility. No group differences were observed in D2/3 receptor binding or DA release. Analyses by sex alone may obscure underlying differences in DA synthesis tied to women\u27s hormone status. Hormonal contraception (in the form of pill, shot, implant, ring, or intrauterine device) is used by ~400 million women worldwide, yet few studies have examined whether chronic hormonal manipulations impact basic properties of the DA system. Findings from this study begin to address this critical gap in women\u27s health