117 research outputs found

    Understanding life-satisfaction changes in post-apartheid South Africa

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    We analyze the large changes in the level and distribution of reported life satisfaction In South Africa from 1993 to 1998, a period spanning the end of apartheid and the creation of a more inclusive democracy. The percentage of black South Africans reporting dissatisfaction with their lives dropped by over two-thirds, despite only modest improvements in material living conditions. Using household surveys five years apart, we show that the vast majority (over 85 percent) of the improved life satisfaction is attributable to changes in the satisfaction derived from specific living conditions, not to changes in the actual level of those living conditions. While some of these shifts are likely attributed to the social churn at the end of apartheid, these changes also indicate changing opportunities for black South Africans. These results are consistent with hedonic adaptation and show that the factors that make people happier can change dramatically over a relatively short time period.Adaptation; Happiness; Oaxaca decomposition; South Africa; Well-Being

    Mass Transfer and Benzene Removal from Air using Latex Rubber Tubing and a Hollow-Fiber Membrane Module

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    A Dense-Phase Latex Rubber Tube and a Polyporous Propylene Hollow-Fiber Membrane Module (HFMM) Were Investigated for Control of Benzene-Contaminated Gas Streams. the Abiotic Mass Flux Observed through the Latex Tube Was 3.9-13 Mg/(Min·m2) for 150 Ppm of Benzene at Various Gas and Liquid Flow Rates, While a 100-Fold Lower Mass Flux Was Observed in the HFMM. after Seeding with an Aromatic-Degrading Culture Enriched from Activated Sludge, the Observed Removal Was 80% of 150 Ppm, Corresponding to a Mass Flux of 45 Mg/(Min·m2). the Observed Mass Flux through the HFMM during Biofiltration Also Rose, to 0.4 Mg/(Min·m2). Because the HFMM Had a 50-Fold Higher Surface Area Than the Latex Tube, the Observed Benzene Removal Was 99.8%. Compared to Conventional Biofilters, the Two Reactors Had Modest Elimination Capacities, 2.5-18 G/(M3·h) in the Latex Tube Membrane Bioreactor and 4.8-58 G/(M3·h) in the HFMM. Although the HFMM Had a Higher Elimination Capacity, the Gas-Phase Pressure Drop Was Much Greater

    Biological Fixed-Film Systems

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    The Microbiological Degradation of Wastewater and its Application using a Fixed-Film Reactor is Reviewed. the Technical and Technological Characteristics, as Well as the Efficiency of Nitrification and Denitrification Processes Were Taken into Consideration. the Review Elucidated the Experimental Measurements of Effective Diffusive Permeabilities and Effective Diffusion Coefficients of Biofilms

    Membrane Process for Biological Treatment of Contaminated Gas Streams

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    A Hollow Fiber Membrane Bioreactor Was Investigated for Control of Air Emissions of Biodegradable Volatile Organic Compounds (VOCs). in the Membrane Bioreactor, Gases Containing VOCs Pass through the Lumen of Microporous Hydrophobic Hollow Fiber Membranes. Soluble Compounds Diffuse through the Membrane Pores and Partition into a VOC Degrading Biofilm. the Hollow Fiber Membranes Serve as a Support for the Microbial Population and Provide a Large Surface Area for VOC and Oxygen Mass Transfer. Experiments Were Performed to Investigate the Effects of Toluene Loading Rate, Gas Residence Time, and Liquid Phase Turbulence on Toluene Removal in a Laboratory-Scale Membrane Bioreactor. Initial Acclimation of the Microbial Culture to Toluene Occurred over a Period of Nine Days, after Which a 70% Removal Efficiency Was Achieved at an Inlet Toluene Concentration of 200 Ppm and a Gas Residence Time of 1.8 S (Elimination Capacity of 20 G M-3 Min-1). at Higher Toluene Loading Rates, a Maximum Elimination Capacity of 42 G M-3 Min-1 Was Observed. in the Absence of a Biofilm (Abiotic Operation), Mass Transfer Rates Were Found to Increase with Increasing Liquid Recirculation Rates. Abiotic Mass Transfer Coefficients Could Be Estimated using a Correlation of Dimensionless Parameters Developed for Heat Transfer. Liquid Phase Recirculation Rate Had No Effect on Toluene Removal When the Biofilm Was Present, However. Three Models of the Reactor Were Created: A Numeric Model, a First-Order Flat Sheet Model, and a Zero-Order Flat Sheet Model. Only the Numeric Model Fit the Data Well, Although Removal Predicted as a Function of Gas Residence Time Disagreed Slightly with that Observed. a Modification in the Model to Account for Membrane Phase Resistance Resulted in an Underprediction of Removal. Sensitivity Analysis of the Numeric Model Indicated that Removal Was a Strong Function of the Liquid Phase Biomass Density and Biofilm Diffusion Coefficient, with Diffusion Rates Below 10-9 M2 S-1 Resulting in Decreased Removal Rates

    Understanding life-satisfaction changes in post-apartheid South Africa

    Get PDF
    We analyze the large changes in the level and distribution of reported life satisfaction In South Africa from 1993 to 1998, a period spanning the end of apartheid and the creation of a more inclusive democracy. The percentage of black South Africans reporting dissatisfaction with their lives dropped by over two-thirds, despite only modest improvements in material living conditions. Using household surveys five years apart, we show that the vast majority (over 85 percent) of the improved life satisfaction is attributable to changes in the satisfaction derived from specific living conditions, not to changes in the actual level of those living conditions. While some of these shifts are likely attributed to the social churn at the end of apartheid, these changes also indicate changing opportunities for black South Africans. These results are consistent with hedonic adaptation and show that the factors that make people happier can change dramatically over a relatively short time period

    Understanding life-satisfaction changes in post-apartheid South Africa

    Get PDF
    We analyze the large changes in the level and distribution of reported life satisfaction In South Africa from 1993 to 1998, a period spanning the end of apartheid and the creation of a more inclusive democracy. The percentage of black South Africans reporting dissatisfaction with their lives dropped by over two-thirds, despite only modest improvements in material living conditions. Using household surveys five years apart, we show that the vast majority (over 85 percent) of the improved life satisfaction is attributable to changes in the satisfaction derived from specific living conditions, not to changes in the actual level of those living conditions. While some of these shifts are likely attributed to the social churn at the end of apartheid, these changes also indicate changing opportunities for black South Africans. These results are consistent with hedonic adaptation and show that the factors that make people happier can change dramatically over a relatively short time period

    Physician Executive Leadership: Student-Led Curriculum to Fill Gaps in Traditional Medical Education

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    Students at Sidney Kimmel Medical College (SKMC) have identified a gap in the traditional medical curriculum surrounding topics such as telehealth, the patient experience, health policy, medical malpractice, and health care entrepreneurship and innovation, and in response have initiated a student-centered, student-led, student-driven program called Physician Executive Leadership (PEL). PEL provides students with a variety of avenues to engage with these topics, such as lectures from leaders in each of these fields, easy access to weekly news articles on current events in health care, targeted review sessions on the US health care system, and the opportunity to voice and develop ideas through an online publication. To identify the gaps in medical education PEL is best suited to fill, we administered a survey to 174 students at Sidney Kimmel Medical College.The survey contained 20 multiple-choice questions to assess general knowledge on health insurance and reimbursement, health care policy and reform, and care quality and patient experience. It also included a subjective self-assessment of students’ understanding of and interest in these topics. Overall, we found that although the traditional medical school curriculum improved students\u27 understanding of these topics from year to year, it is not sufficient on it\u27s own: on average, students failed to achieve a passing score of 70% in any of the categories tested. Further illustrating the importance of this program, students self-identified a gap between their current level of understanding and what they want to know. Please visit our website www.physicianexecutiveleadership.com to learn more!https://jdc.jefferson.edu/pel/1000/thumbnail.jp

    Development of Social Vocalizations in Mice

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    Adult mice are highly vocal animals, with both males and females vocalizing in same sex and cross sex social encounters. Mouse pups are also highly vocal, producing isolation vocalizations when they are cold or removed from the nest. This study examined patterns in the development of pup isolation vocalizations, and compared these to adult vocalizations. In three litters of CBA/CaJ mice, we recorded isolation vocalizations at ages postnatal day 5 (p5), p7, p9, p11, and p13. Adult vocalizations were obtained in a variety of social situations. Altogether, 28,384 discrete vocal signals were recorded using high-frequency-sensitive equipment and analyzed for syllable type, spectral and temporal features, and the temporal sequencing within bouts. We found that pups produced all but one of the 11 syllable types recorded from adults. The proportions of syllable types changed developmentally, but even the youngest pups produced complex syllables with frequency-time variations. When all syllable types were pooled together for analysis, changes in the peak frequency or the duration of syllables were small, although significant, from p5 through p13. However, individual syllable types showed different, large patterns of change over development, requiring analysis of each syllable type separately. Most adult syllables were substantially lower in frequency and shorter in duration. As pups aged, the complexity of vocal bouts increased, with a greater tendency to switch between syllable types. Vocal bouts from older animals, p13 and adult, had significantly more sequential structure than those from younger mice. Overall, these results demonstrate substantial changes in social vocalizations with age. Future studies are required to identify whether these changes result from developmental processes affecting the vocal tract or control of vocalization, or from vocal learning. To provide a tool for further research, we developed a MATLAB program that generates bouts of vocalizations that correspond to mice of different ages

    Hypervirulent Chlamydia trachomatis Clinical Strain Is a Recombinant between Lymphogranuloma Venereum (L2) and D Lineages

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    Chlamydia trachomatis is an obligate intracellular bacterium that causes a diversity of severe and debilitating diseases worldwide. Sporadic and ongoing outbreaks of lymphogranuloma venereum (LGV) strains among men who have sex with men (MSM) support the need for research on virulence factors associated with these organisms. Previous analyses have been limited to single genes or genomes of laboratory-adapted reference strain L2/434 and outbreak strain L2b/UCH-1/proctitis. We characterized an unusual LGV strain, termed L2c, isolated from an MSM with severe hemorrhagic proctitis. L2c developed nonfusing, grape-like inclusions and a cytotoxic phenotype in culture, unlike the LGV strains described to date. Deep genome sequencing revealed that L2c was a recombinant of L2 and D strains with conserved clustered regions of genetic exchange, including a 78-kb region and a partial, yet functional, toxin gene that was lost with prolonged culture. Indels (insertions/deletions) were discovered in an ftsK gene promoter and in the tarp and hctB genes, which encode key proteins involved in replication, inclusion formation, and histone H1-like protein activity, respectively. Analyses suggest that these indels affect gene and/or protein function, supporting the in vitro and disease phenotypes. While recombination has been known to occur for C. trachomatis based on gene sequence analyses, we provide the first whole-genome evidence for recombination between a virulent, invasive LGV strain and a noninvasive common urogenital strain. Given the lack of a genetic system for producing stable C. trachomatis mutants, identifying naturally occurring recombinants can clarify gene function and provide opportunities for discovering avenues for genomic manipulation
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