1,093 research outputs found
Social Welfare Agencies and Social Reform Movements: The Case of the Single Parent Family
To a greater extent than before, social welfare agencies are emphasizing social change over direct services. A social reform movement is a mechanism by which societal and institutional change may be accomplished. The relationship between social welfare organizations and social movements has not been clearly defined. The sociological theories of Smelser, Turner, Killian and others on collective behavior and social movements provide a useful knowledge base for welfare organizations and professionals espousing social reform goals. The single parent family population is discussed as a group with the potential to generate into a social reform movement
The Testing Culture and the Persistence of High Stakes Testing Reforms
The purposes of this critical analysis are to clarify why high stakes testing reforms have become so prevalent in the United States and to explain the connection between current federal and state emphases on standardized testing reforms and educational opportunities. The article outlines the policy context for high stakes examinations, as well as the ideas of testing and accountability as major tenets of current education reform and policy. In partial explanation of the widespread acceptance and use of standardized tests in the United States, we argue that there is a pervasive testing culture, in addition to other contributing factors such as administrative utility, profit motives, and political ideology. Finally, we offer a critique of high stakes testing reforms in light of concerns about equality of educational opportunity
Liver Sinusoid on a Chip: Long-Term Layered Co-Culture of Primary Rat Hepatocytes and Endothelial Cells in Microfluidic Platforms
We describe the generation of microfluidic platforms for the co-culture of primary hepatocytes and endothelial cells; these platforms mimic the architecture of a liver sinusoid. This paper describes a progressional study of creating such a liver sinusoid on a chip system. Primary rat hepatocytes (PRHs) were co-cultured with primary or established endothelial cells in layers in single and dual microchannel configurations with or without continuous perfusion. Cell viability and maintenance of hepatocyte functions were monitored and compared for diverse experimental conditions. When primary rat hepatocytes were co-cultured with immortalized bovine aortic endothelial cells (BAECs) in a dual microchannel with continuous perfusion, hepatocytes maintained their normal morphology and continued to produce urea for at least 30 days. In order to demonstrate the utility of our microfluidic liver sinusoid platform, we also performed an analysis of viral replication for the hepatotropic hepatitis B virus (HBV). HBV replication, as measured by the presence of cell-secreted HBV DNA, was successfully detected. We believe that our liver model closely mimics the in vivo liver sinusoid and supports long-term primary liver cell culture. This liver model could be extended to diverse liver biology studies and liver-related disease research such as drug induced liver toxicology, cancer research, and analysis of pathological effects and replication strategies of various hepatotropic infectious agents
Risk Analysis Associated with Loss of Toxic Gases During Orion Landing and Recovery Operations
Mission, landing and recovery operations for the Orion crew module involve reentry into the Earth's atmosphere and the deployment of three Nomex parachutes to slow the descent before landing along the west coast of the United States. Orion may have residual fuel (hydrazine, N2H4) or coolant (ammonia, NH3) on board which are both highly toxic to crew in the event of exposure. These risks were evaluated using a first principles analysis approach through fluid dynamics modeling. Plume calculations were first performed with the ANSYS Fluent computational fluid dynamics code. Data were then extracted at locations relevant to crew safety such as the snorkel fan inlet and the egress hatch. Mixing calculations were performed to quantify exposure concentrations within the crew bay before and during egress and departure. Finally, results included herein were used to inform the Orion post-landing Concept of Operations (ConOps) so that strategies could be formulated to maintain crew safety in the event of the loss of fuel or coolant
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Placental Structure in Preterm Birth Among HIV-Positive Versus HIV-Negative Women in Kenya.
BackgroundPreterm birth (PTB) is a major cause of infant morbidity and mortality in developing countries. Recent data suggest that in addition to Human Immunodeficiency Virus (HIV) infection, use of antiretroviral therapy (ART) increases the risk of PTB. As the mechanisms remain unexplored, we conducted this study to determine whether HIV and ART were associated with placental changes that could contribute to PTB.SettingWe collected and evaluated placentas from 38 HIV-positive women on ART and 43 HIV-negative women who had preterm deliveries in Nairobi, Kenya.MethodsAnatomical features of the placentas were examined at gross and microscopic levels. Cases were matched for gestational age and compared by the investigators who were blinded to maternal HIV serostatus.ResultsAmong preterm placentas, HIV infection was significantly associated with thrombosis (P = 0.001), infarction (P = 0.032), anomalies in cord insertion (P = 0.02), gross evidence of membrane infection (P = 0.043), and reduced placental thickness (P = 0.010). Overall, preterm placentas in both groups were associated with immature villi, syncytial knotting, villitis, and deciduitis. Features of HIV-positive versus HIV-negative placentas included significant fibrinoid deposition with villus degeneration, syncytiotrophoblast delamination, red blood cell adhesion, hypervascularity, and reduction in both surface area and perimeter of the terminal villi.ConclusionsThese results imply that HIV infection and/or ART are associated with morphological changes in preterm placentas that contribute to delivery before 37 weeks. Hypervascularity suggests that the observed pathologies may be attributable, in part, to hypoxia. Further research to explore potential mechanisms will help elucidate the pathways that are involved perhaps pointing to interventions for decreasing the risk of prematurity among HIV-positive women
The Touch Thimble: Providing Fingertip Contact Feedback During Point-Force Haptic Interaction
Touching a real object with your fingertip provides simultaneous tactile and force feedback, yet most haptic interfaces for virtual environments can convey only one of these two essential modalities. To address this opportunity, we designed, prototyped, and evaluated the Touch Thimble, a new fingertip device that provides the user with the cutaneous sensation of making and breaking contact with virtual surfaces. Designed to attach to the endpoint of an impedance-type haptic interface like a SensAble Phantom, the Touch Thimble includes a slightly oversize cup that is suspended around the fingertip by passive springs. When the haptic interface applies contact forces from the virtual environment, the springs deflect to allow contact between the user\u27s fingertip and the inner surface of the cup. We evaluated a prototype Touch Thimble against a standard thimble in a formal user study and found that it did not improve nor degrade subjects\u27 ability to recognize smoothly curving surfaces. Although four of the eight subjects preferred it to the standard interface, overall the Touch Thimble made subjects slightly slower at recognizing the presented shapes. Detailed subject comments point out strengths and weaknesses of the current design and suggest avenues for future development of the device
Prevalence and risk factors of asymptomatic malaria among underfive children in Huye District, Southern Rwanda
Background: Enhanced malaria control has resulted in its reduction in some areas of Sub Saharan Africa including Rwanda. However, asymptomatic hosts serve as a reservoir for the malaria parasite for communities. The objective of this study was to determine the prevalence of malaria parasites and risk factors associated with malaria infection among children underfive years in Huye district, Rwanda.Methods: This community-based cross sectional study was conducted from May to June 2016 among underfive years children. Asymptomatic children underfive years of age were randomly selected from 13 villages. Thick and thin blood smears were prepared from each child for malaria parasite diagnosis. Interviews with parents or guardians were conducted to collect data on malaria associated risk factors. Observations were made of the presence of mosquito breeding sites near and around the homestead.Results: A total of 222 children were included in the study. Nearly a third (28.8%) of the children were within the age of 25-36 months. The majority (54%) of the children were females. Most of the parents/guardians were married (95.9%), nearly all (99.5%) had attended primary school and most (97.3%) were peasants. The overall Plasmodium falciparum prevalence in children was 12.2%. Children aged 1 to 12 months were 3.5 times more likely to have malaria parasites than children aged 13 to 59 months [AOR=3.56; 95%CI=1.18-10.71; p=0.024]. Children who were not sleeping under insecticide treated nets were 15 times more likely to be infected with malaria parasites compared to those who were sleeping under nets [AOR=15.27; 95%CI=4.42-52.82; p<0.001].Conclusion: Malaria parasite prevalence in under-five year children in Huye District, Rwanda is moderate. The asymptomatic infections in the community forms a reservoir for transmission in the area. Young age of the child and not sleeping under mosquito net were associated with malaria parasite infection. The continuing use of mosquito nets needs to be emphasized
Improving the Specificity of Plasmodium falciparum Malaria Diagnosis in High-Transmission Settings with a Two-Step Rapid Diagnostic Test and Microscopy Algorithm
ABSTRACT Poor specificity may negatively impact rapid diagnostic test (RDT)-based diagnostic strategies for malaria. We performed real-time PCR on a subset of subjects who had undergone diagnostic testing with a multiple-antigen (histidine-rich protein 2 and pan -lactate dehydrogenase pLDH [HRP2/pLDH]) RDT and microscopy. We determined the sensitivity and specificity of the RDT in comparison to results of PCR for the detection of Plasmodium falciparum malaria. We developed and evaluated a two-step algorithm utilizing the multiple-antigen RDT to screen patients, followed by confirmatory microscopy for those individuals with HRP2-positive (HRP2 + )/pLDH-negative (pLDH − ) results. In total, dried blood spots (DBS) were collected from 276 individuals. There were 124 (44.9%) individuals with an HRP2 + /pLDH + result, 94 (34.1%) with an HRP2 + /pLDH − result, and 58 (21%) with a negative RDT result. The sensitivity and specificity of the RDT compared to results with real-time PCR were 99.4% (95% confidence interval [CI], 95.9 to 100.0%) and 46.7% (95% CI, 37.7 to 55.9%), respectively. Of the 94 HRP2 + /pLDH − results, only 32 (34.0%) and 35 (37.2%) were positive by microscopy and PCR, respectively. The sensitivity and specificity of the two-step algorithm compared to results with real-time PCR were 95.5% (95% CI, 90.5 to 98.0%) and 91.0% (95% CI, 84.1 to 95.2), respectively. HRP2 antigen bands demonstrated poor specificity for the diagnosis of malaria compared to that of real-time PCR in a high-transmission setting. The most likely explanation for this finding is the persistence of HRP2 antigenemia following treatment of an acute infection. The two-step diagnostic algorithm utilizing microscopy as a confirmatory test for indeterminate HRP2 + /pLDH − results showed significantly improved specificity with little loss of sensitivity in a high-transmission setting
Mid-Infrared Spectroscopy of Uranus from the Spitzer Infrared Spectrometer: 2. Determination of the Mean Composition of the Upper Troposphere and Stratosphere
Mid-infrared spectral observations Uranus acquired with the Infrared
Spectrometer (IRS) on the Spitzer Space Telescope are used to determine the
abundances of C2H2, C2H6, CH3C2H, C4H2, CO2, and tentatively CH3 on Uranus at
the time of the 2007 equinox. For vertically uniform eddy diffusion
coefficients in the range 2200-2600 cm2 s-1, photochemical models that
reproduce the observed methane emission also predict C2H6 profiles that compare
well with emission in the 11.6-12.5 micron wavelength region, where the nu9
band of C2H6 is prominent. Our nominal model with a uniform eddy diffusion
coefficient Kzz = 2430 cm2 sec-1 and a CH4 tropopause mole fraction of 1.6x10-5
provides a good fit to other hydrocarbon emission features, such as those of
C2H2 and C4H2, but the model profile for CH3C2H must be scaled by a factor of
0.43, suggesting that improvements are needed in the chemical reaction
mechanism for C3Hx species. The nominal model is consistent with a CH3D/CH4
ratio of 3.0+-0.2x10-4. From the best-fit scaling of these photochemical-model
profiles, we derive column abundances above the 10-mbar level of 4.5+01.1/-0.8
x 10+19 molecule-cm-2 for CH4, 6.2 +- 1.0 x 10+16 molecule-cm-2 for C2H2 (with
a value 24% higher from a different longitudinal sampling), 3.1 +- 0.3 x 10+16
molecule-cm-2 for C2H6, 8.6 +- 2.6 x 10+13 molecule-cm-2 for CH3C2H, 1.8 +- 0.3
x 10+13 molecule-cm-2 for C4H2, and 1.7 +- 0.4 x 10+13 molecule-cm-2 for CO2 on
Uranus. Our results have implications with respect to the influx rate of
exogenic oxygen species and the production rate of stratospheric hazes on
Uranus, as well as the C4H2 vapor pressure over C4H2 ice at low temperatures
Characterization of malaria vectors in Huye District, Southern Rwanda
Background: Effective control of malaria requires knowledge of vector species, their feeding and resting behaviour as well as breeding habitats. The objective of this study was to determine malaria vector species abundance and identify their larval habitats in Huye district, southern Rwanda.Methods: Adult mosquitoes were collected indoors using light trap and pyrethrum spray catch techniques, and outdoors using light traps. Female Anopheles mosquitoes were identified to species level by morphological characteristics. Enzyme-linked Immunosorbent Assay (ELISA) was used to screen for Plasmodium falciparum circumsporozoite protein and host blood meal sources. Anopheles larvae were sampled using dippers and raised into adult mosquitoes which were identified morphologically.Results: Anopheles gambiae sensu lato comprised of 70% of the 567 Anopheles collected. Other Anopheles species identified were An. funestus 4%, An. squamosus 16.5%, An. maculipalpis 6.5%, An. ziemanni 1.7%, An. pharoensis 1.2 % and An. coustani 0.1%. The majority, 63.5% of the collected mosquitoes were from indoors collections. The overall human blood index was 0.509. The P. falciparum circumsporozoite protein was found in 11 mosquitos including 8 Anopheles gambiae s.l. and 3 secondary vectors out of the 567 tested. The overall sporozoite rate was 1.9%. A total of 661 Anopheline larvae from 22 larval habitats were collected. They comprised of An. gambiae s.l. (89%) and An. ziemanni (11%). The absolute breeding index was 86.4%. The most common larval habitats were in full sunlight with still water like rice paddies and pools of stagnant water.Conclusion: These findings show that Anopheles gambiae s.l. is the dominant malaria vector in the area with other vectors playing a secondary role in malaria transmission. Malaria interventions need to be strengthened to reduce even further the malaria transmission in the area.
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