Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 27
Filtrar
1.
Oxf Econ Pap ; 75(4): 1053-1072, 2023 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-37719930

RESUMO

Experiments indicate that adult role-modeling of giving has a causal effect on giving done by children, but a previous investigation using data from a natural setting suggests zero causal effect of parent role-modeling on their adolescents' giving. This article presents new evidence about the divergent findings: (i) parent giving does not automatically translate into adolescents knowing that their parents give, and (ii) adolescents are much less likely to know that their parents give if parents give from time-to-time. The results suggest new experimental designs that randomize (a) the frequency of role-modeling, (b) communication approaches that explain role-modeling actions to children, and (c) whether the receiving organization is in-group or out-group. The practical implications of the results are that frequent giving by a parent is necessary for adolescents to successfully 'receive' the role model, but may not be sufficient. Purposeful communication is needed to ensure that adolescents know that their parents are giving.

2.
J Hazard Mater ; 459: 132102, 2023 10 05.
Artigo em Inglês | MEDLINE | ID: mdl-37531758

RESUMO

Remediation of petroleum-contaminated soil is a widely concerned challenge. As an ecofriendly method, the performance improvement of indigenous microbial degradation is facing the bottleneck. In this study, a strain with high efficiency of petroleum degradation was isolated from the petroleum-contaminated soil and identified and named as Bacillus sp. Z-13. The strain showed the ability to produce lipopeptide surfactant which could improve 66% more petroleum hydrocarbons eluted. Strain Z-13 and its biosurfactant exhibited broad environmental adaptability to salinity (0-8%), pH (6-9) and temperature (15-45 °C). With the addition of strain Z-13 and the stimulation of NH4Cl, up to 59% of the petroleum in the contaminated soil was removed at the carbon to nitrogen ratio of 10. Microbial community analysis showed that petroleum-degrading bacteria, represented by Bacillus, became the dominant species at genus level and played an important role in the remediation. Additionally, ammonium stimulation facilitated both pathways of ammonium assimilation and nitrification in native microorganisms to achieve efficient degradation of petroleum hydrocarbons. This study could provide a promising approach for stable, environmental-friendly and efficient remediation of petroleum-contaminated soil.


Assuntos
Bacillus , Recuperação e Remediação Ambiental , Petróleo , Poluentes do Solo , Bacillus/metabolismo , Biodegradação Ambiental , Petróleo/metabolismo , Solo/química , Nitrogênio/metabolismo , Poluentes do Solo/metabolismo , Bactérias/metabolismo , Hidrocarbonetos/metabolismo , Microbiologia do Solo
3.
Int J Pharm ; 633: 122607, 2023 Feb 25.
Artigo em Inglês | MEDLINE | ID: mdl-36641138

RESUMO

Ascertaining compound exposure and its spatial distribution are essential steps in the drug development process. Desorption electrospray ionization mass spectrometry (DESI-MSI) is a label-free imaging technique capable of simultaneously identify and visualize the distribution of a diverse range of biomolecules. In this study, DESI-MSI was employed to investigate spatial distribution of tolcapone in rat liver and brain coronal - frontal and striatal -sections after a single oral administration of 100 mg/Kg of tolcapone, brain-penetrant compound. Tolcapone was evenly distributed in liver tissue sections whereas in the brain it showed differential distribution across brain regions analyzed, being mainly located in the olfactory bulb, basal forebrain region, striatum, and pre-frontal cortex (PFC; cingulate, prelimbic and infralimbic area). Tolcapone concentration in tissues was compared using DESI-MSI and liquid-chromatography mass spectrometry (LC-MS/MS). DESI-MSI technique showed a higher specificity on detecting tolcapone in liver sections while in the brain samples DESI-MSI did not allow a feasible quantification. Indeed, DESI-MSI is a qualitative technique that allows to observe heterogeneity on distribution but more challenging regarding accurate measurements. Overall, tolcapone was successfully localized in liver and brain tissue sections using DESI-MSI, highlighting the added value that this technique could provide in assisting tissue-specific drug distribution studies.


Assuntos
Encéfalo , Espectrometria de Massas em Tandem , Ratos , Animais , Tolcapona , Cromatografia Líquida , Fígado , Espectrometria de Massas por Ionização por Electrospray/métodos
4.
J Popul Econ ; 35(3): 1007-1036, 2022 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-35599989

RESUMO

I study the short-run and long-run effects of exposure to peers from disrupted families in adolescence. Using the National Longitudinal Study of Adolescent to Adult Health (Add Health) data, I find that girls are mostly unaffected by peers from disrupted families, while boys exposed to more peers from disrupted families exhibit more school problems in adolescence and higher arrest probabilities, less stable jobs and higher probabilities of suffering from financial stress as young adults. These results suggest negative effects on non-cognitive skills but no effect on cognitive skills, as measured by academic performance. The dramatic increase in family disruption in the United States should thus receive more attention, as the intergenerational mobility and inequality consequences could be larger than anticipated as a result of classroom spillovers.

5.
Pharmacol Res ; 180: 106230, 2022 06.
Artigo em Inglês | MEDLINE | ID: mdl-35483515

RESUMO

Ischemic/reperfusion (IR) can cause adverse reactions including apoptosis, oxidative stress, and inflammation, but the existing therapeutic strategies have been limited. Moreover, the regulation of microglia plays an important role in brain injury after reperfusion. Hence, it is imperative to find new and effective drugs for modulating microglia to treat IR brain injury. Cyclic peptide compound cyclo-(Phe-Tyr) (Sparganin C, SC) is a compound isolated from Sparganii Rhizoma. However, the protective effects of SC on the central nervous system are rather unclear. In an attempt to elucidate the protective effects and mechanism of SC on cerebral damage induced by the IR, we used a middle cerebral artery occlusion reperfusion (MCAO/R) model in rats and discovered that SC significantly decreased the size of cerebral infarcts, improved neurological scores, and blocked inflammatory and oxidative factor release. Using RNA-Seq and metabolomics association analyses, SC was shown to have a protective impact through the JUNB and SOX5-related pathways. Metabolomic analysis revealed twenty-eight differentially expressed biomarkers. In addition, the detection of SC content in brain tissue using LC/MS revealed that SC had blood-brain barrier penetration. To investigate the mechanism, we established an in vitro BV2 cell oxygen-glucose deprivation/reperfusion (OGD/R) model and used siRNA as well as an inhibitor. The protective effects of SC were dependent on the JUNB and SOX5 to inhibit inflammation and apoptosis in microglia. Our findings revealed for the first that SC against IR injury by reducing inflammation and apoptosis while simultaneously acting as potential therapeutic lead compound for ischemic stroke.


Assuntos
Lesões Encefálicas , Traumatismo por Reperfusão , Animais , Encéfalo/metabolismo , Lesões Encefálicas/metabolismo , Dipeptídeos/metabolismo , Dipeptídeos/farmacologia , Dipeptídeos/uso terapêutico , Inflamação/tratamento farmacológico , NF-kappa B/metabolismo , Fosfatidilinositol 3-Quinases/metabolismo , Proteínas Proto-Oncogênicas c-akt/metabolismo , Ratos , Reperfusão , Traumatismo por Reperfusão/tratamento farmacológico , Traumatismo por Reperfusão/metabolismo
6.
J Neuroinflammation ; 18(1): 157, 2021 Jul 17.
Artigo em Inglês | MEDLINE | ID: mdl-34273979

RESUMO

BACKGROUND: Repetitive mild traumatic brain injury (mTBI) can result in chronic visual dysfunction. G-protein receptor 110 (GPR110, ADGRF1) is the target receptor of N-docosahexaenoylethanolamine (synaptamide) mediating the anti-neuroinflammatory function of synaptamide. In this study, we evaluated the effect of an endogenous and a synthetic ligand of GPR110, synaptamide and (4Z,7Z,10Z,13Z,16Z,19Z)-N-(2-hydroxy-2-methylpropyl) docosa-4,7,10,13,16,19-hexaenamide (dimethylsynaptamide, A8), on the mTBI-induced long-term optic tract histopathology and visual dysfunction using Closed-Head Impact Model of Engineered Rotational Acceleration (CHIMERA), a clinically relevant model of mTBI. METHODS: The brain injury in wild-type (WT) and GPR110 knockout (KO) mice was induced by CHIMERA applied daily for 3 days, and GPR110 ligands were intraperitoneally injected immediately following each impact. The expression of GPR110 and proinflammatory mediator tumor necrosis factor (TNF) in the brain was measured by using real-time quantitative reverse transcription polymerase chain reaction (qRT-PCR) in an acute phase. Chronic inflammatory responses in the optic tract and visual dysfunction were assessed by immunostaining for Iba-1 and GFAP and visual evoked potential (VEP), respectively. The effect of GPR110 ligands in vitro was evaluated by the cyclic adenosine monophosphate (cAMP) production in primary microglia isolated from adult WT or KO mouse brains. RESULTS: CHIMERA injury acutely upregulated the GPR110 and TNF gene level in mouse brain. Repetitive CHIMERA (rCHIMERA) increased the GFAP and Iba-1 immunostaining of glia cells and silver staining of degenerating axons in the optic tract with significant reduction of N1 amplitude of visual evoked potential at up to 3.5 months after injury. Both GPR110 ligands dose- and GPR110-dependently increased cAMP in cultured primary microglia with A8, a ligand with improved stability, being more effective than synaptamide. Intraperitoneal injection of A8 at 1 mg/kg or synaptamide at 5 mg/kg significantly reduced the acute expression of TNF mRNA in the brain and ameliorated chronic optic tract microgliosis, astrogliosis, and axonal degeneration as well as visual deficit caused by injury in WT but not in GPR110 KO mice. CONCLUSION: Our data demonstrate that ligand-induced activation of the GPR110/cAMP system upregulated after injury ameliorates the long-term optic tract histopathology and visual impairment caused by rCHIMERA. Based on the anti-inflammatory nature of GPR110 activation, we suggest that GPR110 ligands may have therapeutic potential for chronic visual dysfunction associated with mTBI.


Assuntos
Concussão Encefálica/complicações , Etanolaminas/metabolismo , Etanolaminas/farmacologia , Gliose/tratamento farmacológico , Gliose/metabolismo , Trato Óptico/efeitos dos fármacos , Trato Óptico/patologia , Receptores Acoplados a Proteínas G/metabolismo , Animais , Encéfalo/metabolismo , Encéfalo/patologia , Concussão Encefálica/patologia , Técnicas de Cultura de Células , AMP Cíclico/metabolismo , Modelos Animais de Doenças , Eletrorretinografia , Potenciais Evocados Visuais , Gliose/complicações , Inflamação , Ligantes , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Microglia/metabolismo , Trato Óptico/lesões , Fator de Necrose Tumoral alfa/metabolismo , Visão Ocular
7.
Am Econ Rev ; 111(7): 2342-2375, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-37201159

RESUMO

Can increasing control over earnings incentivize a woman to work, and thereby influence norms around gender roles? We randomly varied whether rural Indian women received bank accounts, training in account use, and direct deposit of public sector wages into their own (versus husbands') accounts. Relative to the accounts only group, women who also received direct deposit and training worked more in public and private sector jobs. The private sector result suggests gender norms initially constrained female employment. Three years later, direct deposit and training broadly liberalized women's own work-related norms, and shifted perceptions of community norms.

8.
Pest Manag Sci ; 77(1): 264-272, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-32696568

RESUMO

BACKGROUND: Micromelalopha siversi (Staudinger) (Lepidoptera: Notodontidae) is a defoliator of poplar trees, Populus spp. (Salicaceae). In our previous study, 13,15-octadecadienal has been conformed as a female-produced candidate sex pheromone component of M. siversi, but the Z/E stereochemistry of the 1,3-diene system has not been identified so far. RESULTS: Four unsaturated aliphatic aldehydes, Z13,E15-18:Ald, Z13,Z15-18:Ald, E13,E15-18:Ald, and E13,Z15-18:Ald, were synthesized from the commercially available 12-bromo-1-decanol mainly by alkylation of lithium alkyne, normal Wittig or Wittig-Schlosser olefination, and hydroboration-protonolysis. According to gas chromatography (GC) analysis of pheromone gland extracts, Z13,E15-18:Ald was the main component, and a small amount of Z13,Z15-18:Ald was also detected, with a ratio of approximately 7:3. However, the results of GC-electroantennographic detection (GC-EAD) showed that Z13,E15-18:Ald was the only compound with electrophysiological activity, whereas Z13,Z15-18:Ald elicited no activity. In the field, traps baited with only Z13,E15-18:Ald resulted in much superior results to those with Z13,Z15-18:Ald as well as the Z13,E15-18:Ald and Z13,Z15-18:Ald binary mixture. CONCLUSIONS: Based on geometrically selective synthesis and bioactivity tests, the active sex pheromone component of M. siversi has been identified as Z13,E15-18:Ald, the pheromone component that has not been identified in Lepidoptera before. The synthetic component was attractive to male moths in preliminary field traps, which provides novel technologies to monitor and control this pest.


Assuntos
Lepidópteros , Mariposas , Atrativos Sexuais , Aldeídos , Animais , Cromatografia Gasosa , Feminino , Masculino , Feromônios , Atrativos Sexuais/farmacologia
9.
Am Econ Rev Insights ; 2(1): 125-141, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-32968736

RESUMO

Using millions of historical census records and modern birth certificates, we document that immigrants assimilated into US society at similar rates in the past and present. We measure cultural assimilation as immigrants giving their children less foreign names after spending more time in the United States, and show that immigrants erase about one-half of the naming gap with natives after 20 years both historically and today. Immigrants from poorer countries choose more foreign names upon first arrival in both periods but are among the fastest to shift toward native-sounding names. We find substantial cultural assimilation for immigrants of all education levels.

10.
Am Econ Rev ; 110(8): 2454-2484, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-34526729

RESUMO

Social network data are often prohibitively expensive to collect, limiting empirical network research. We propose an inexpensive and feasible strategy for network elicitation using Aggregated Relational Data (ARD): responses to questions of the form "how many of your links have trait k ?" Our method uses ARD to recover parameters of a network formation model, which permits sampling from a distribution over node- or graph-level statistics. We replicate the results of two field experiments that used network data and draw similar conclusions with ARD alone.

11.
Econometrica ; 88(2): 727-797, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-36071951

RESUMO

This research advances the hypothesis and establishes empirically that interpersonal population diversity, rather than fractionalization or polarization across ethnic groups, has been pivotal to the emergence, prevalence, recurrence, and severity of intrasocietal conflicts. Exploiting an exogenous source of variations in population diversity across nations and ethnic groups, as determined predominantly during the exodus of humans from Africa tens of thousands of years ago, the study demonstrates that population diversity, and its impact on the degree of diversity within ethnic groups, has contributed significantly to the risk and intensity of historical and contemporary civil conflicts. The findings arguably reflect the contribution of population diversity to the non-cohesivnesss of society, as reflected partly in the prevalence of mistrust, the divergence in preferences for public goods and redistributive policies, and the degree of fractionalization and polarization across ethnic, linguistic, and religious groups.

12.
J Chem Ecol ; 44(3): 257-267, 2018 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-29376213

RESUMO

The European pepper moth (Duponchelia fovealis, Lepidoptera, Crambidae, Spilomelinae) is an invasive pest of greenhouses in many countries, causing serious damages to horticultural plants. Coupled gas chromatographic-electroantennographic detection analysis of the female gland extract revealed two antennally active peaks. Using coupled gas chromatography-mass spectrometry (GC-MS), one was identified as (Z)-11-hexadecenal (Z11-16:Ald); however, further analysis on different types of capillary columns indicated that the second active compound has two different isomers, (E)-13-octadecenal (E13-18:Ald) and (Z)-13-octadecenal (Z13-18:Ald). The approximate ratio of E13-18:Ald, Z13-18:Ald and Z11-16:Ald in the crude pheromone gland extract was 10:1:0.1, respectively. Single sensillum recordings showed that there was one sensory neuron that responded with a high amplitude spike to both E13-18:Ald and Z13-18:Ald, while another neuron housed in the same sensillum responded to Z11-16:Ald. Field evaluation of the identified compounds indicated that the E13-18:Ald was necessary to evoke the attraction of males; although the presence of Z13-18:Ald and Z11-16:Ald increased the catches in traps. The highest number of caught males was achieved when E13-18:Ald, Z13-18:Ald and Z11-16:Ald were present in baits in the same ratio as in the female gland extract. This pheromone can be used in a monitoring strategy and could potentially lead to the development of mating disruption.


Assuntos
Ambiente Controlado , Espécies Introduzidas , Mariposas/metabolismo , Atrativos Sexuais/análise , Atrativos Sexuais/biossíntese , Animais , Bioensaio , Fenômenos Eletrofisiológicos , Feminino , Mariposas/fisiologia , Atrativos Sexuais/química
13.
Artigo em Inglês | MEDLINE | ID: mdl-30417075

RESUMO

This paper provides a unique illustration of the benefits of affirmative action in higher educaiton. It focuses on China in the early 21st Century to gauge the impacts of advantges afforded to ethnic minority group members in admissions to colleges and univerities. It specifically addresses a variant of the mismatch hypothesis that alleges that minority students sorted into higher ranked universities are worse off than equallty qualified minorities attending lower-ranked universities. In particular, we examine the expected earnings of minorities vs non-minorities attending elite vs less selective colleges and universities in China. The paper utilizes data from the 2002 Chinese Household Income Project to estimate the labor market return to graduating from college relative to high school to assess the impact of post-reform affirmative action in college/univerity admissions in China. Parameter estimates of heterogeneous treatment effects reveal that for minorities, the average treatment effect of earning a baccalaureate degree from colleges/universities ranked good and very good is high relative to the Han majority, and for those actually receiving the treatment from colleges/universities ranked good, and would be positive for those who could have earned a baccalaureate degree from colleges/universities ranked good and very good, but did not. Our results suggest that post-reform affirmative action education policies in China have been effective at improving the education and labor market outcomes of minorities, and that existing minority-Han disparities can be eliminated, and Chinese economic growth can be enhanced, by further expanding the pipeline of minorities that complete high school and enter into colleges/universities that grant baccalaureate degrees. Our findings suggest that the mismatch hypothesis cannot be viewed as a universal phenomenon that renders affirmative action in college/university admissions an ineffective policy tool to redress/remedy historic discrimination against minority groups.

14.
Br J Nutr ; 116(12): 2044-2052, 2016 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-28025954

RESUMO

Diet and nutritional factors have emerged as possible interventions for inflammatory bowel diseases (IBD), which are characterised by chronic uncontrolled inflammation of the intestinal mucosa. Microalgal species are a promising source of n-3 PUFA and derived oxylipins, which are lipid mediators with a key role in the resolution of inflammation. The aim of the present study was to investigate the effects of an oxylipin-containing lyophilised biomass from Chlamydomonas debaryana on a recurrent 2,4,6-trinitrobenzenesulfonic acid (TNBS)-induced colitis mice model. Moderate chronic inflammation of the colon was induced in BALB/c mice by weekly intracolonic instillations of low dose of TNBS. Administration of the lyophilised microalgal biomass started 2 weeks before colitis induction and was continued throughout colitis development. Mice were killed 48 h after the last TNBS challenge. Oral administration of the microalgal biomass reduced TNBS-induced intestinal inflammation, evidenced by an inhibition of body weight loss, an improvement in colon morphology and a decrease in pro-inflammatory cytokines TNF-α, IL-1ß, IL-6 and IL-17. This product also down-regulated colonic expressions of inducible nitric oxide, cyclo-oxygenase 2 and NF-κB, as well as increased PPAR-γ. In addition, lyophilised microalgal biomass up-regulated the expressions of the antioxidant transcription factor nuclear factor E2-related factor 2 and the target gene heme oxygenase 1. This study describes for the first time the prophylactic effects of an oxylipin-containing lyophilised microalgae biomass from C. debaryana in the acute phase of a recurrent TNBS-induced colitis model in mice. These findings suggest the potential use of this microalga, or derived oxylipins, as a nutraceutical in the treatment of IBD.


Assuntos
Anti-Inflamatórios não Esteroides/uso terapêutico , Colite Ulcerativa/prevenção & controle , Colo/imunologia , Suplementos Nutricionais , Mucosa Intestinal/imunologia , Microalgas/química , Oxilipinas/uso terapêutico , Ração Animal , Animais , Anti-Inflamatórios não Esteroides/administração & dosagem , Biomassa , Chlamydomonas/química , Colite Ulcerativa/dietoterapia , Colite Ulcerativa/imunologia , Colite Ulcerativa/fisiopatologia , Colo/metabolismo , Colo/patologia , Citocinas/antagonistas & inibidores , Citocinas/metabolismo , Modelos Animais de Doenças , Progressão da Doença , Feminino , Liofilização , Regulação da Expressão Gênica , Mucosa Intestinal/metabolismo , Mucosa Intestinal/patologia , Camundongos Endogâmicos BALB C , Infiltração de Neutrófilos , Estresse Oxidativo , Oxilipinas/administração & dosagem , Prevenção Secundária , Ácido Trinitrobenzenossulfônico
15.
Fitoterapia ; 112: 38-44, 2016 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-27156871

RESUMO

Eight new urushiol-type compounds (1-7b), along with seven known compounds were isolated from the resin of Toxicodendron vernicifluum Stokes. Their structures were determined by extensive spectroscopic methods, included (1)H NMR, (13)C NMR, HMQC, HMBC, HRESIMS, EI-MS in combination with CD methods. All the compounds except 7a and 7b were evaluated for their anti-platelet aggregation activities in vitro. Among them, compound 5 (IC50=5.12±0.85µmol/L), with a vic-diol moiety in the long alkyl chain showed the most potent inhibitory of platelet aggregation activity induced by ADP. In addition, compound 6 showed the effect of anti-platelet aggregation induced by AA with the IC50 value of 3.09±0.70µmol/L. Thus, these compounds might be the active components to the traditional use of Resina Toxicodendri for breaking up blood stasis, which could be related to the anti-platelet aggregation.


Assuntos
Catecóis/química , Agregação Plaquetária/efeitos dos fármacos , Resinas Vegetais/química , Toxicodendron/química , Animais , Catecóis/isolamento & purificação , Estrutura Molecular , Coelhos
16.
Econ Hum Biol ; 12: 140-52, 2014 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-24361085

RESUMO

This paper investigates the effect of body size on dating and sexual experiences of white (non-Hispanic) and African American (non-Hispanic) female adolescents. Using data from Add-Health, we estimate the effects of obesity and BMI z-score on the probability of having been involved in a romantic relationship, having ever been touched in the genital area in a sexual way, and having ever engaged in sexual intercourse. We find that obese white teenage girls are less likely to have been in a romantic relationship compared to their non-obese counterparts. In addition, obese white girls are less likely to ever have had sex (intercourse) or to ever have been intimate. There are no systematic differences in relationship experiences and sexual behaviors between obese and non-obese black girls. Overall, the estimated relationships are very robust to common environmental influences at the school-level and to the inclusion of proxies for low self-esteem, attitudes toward sex and interviewer assessment of appearance and personality. Instrumental variables estimates and estimates from models with lagged weight status confirm the overall patterns.


Assuntos
Comportamento do Adolescente/etnologia , Negro ou Afro-Americano/estatística & dados numéricos , Imagem Corporal/psicologia , Obesidade Infantil/etnologia , Comportamento Sexual/etnologia , População Branca/estatística & dados numéricos , Adolescente , Comportamento do Adolescente/psicologia , Negro ou Afro-Americano/psicologia , Índice de Massa Corporal , Feminino , Inquéritos Epidemiológicos , Humanos , Estudos Longitudinais , Obesidade Infantil/psicologia , Estigma Social , População Branca/psicologia
17.
J Health Econ ; 33: 113-25, 2014 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-24316457

RESUMO

This paper proposes a theory for the social evolution of obesity. It considers a society in which individuals experience utility from consumption of food and non-food, the state of their health, and the evaluation of their appearance by others. The theory explains under which conditions poor persons are more prone to be overweight although eating is expensive and it shows how obesity occurs as a social phenomenon such that body mass continues to rise long after the initial cause (e.g. a lower price of food) is gone. The paper investigates the determinants of a steady state at which the median person is overweight and how an originally lean society arrives at such a steady state. Extensions of the theory towards dietary choice and the possibility to exercise in order to lose weight demonstrate robustness of the basic mechanism and provide further interesting results.


Assuntos
Obesidade/epidemiologia , Comportamento Social , Atitude Frente a Saúde , Abastecimento de Alimentos , Nível de Saúde , Humanos , Modelos Teóricos , Obesidade/etiologia , Obesidade/psicologia , Sobrepeso/epidemiologia , Sobrepeso/etiologia , Sobrepeso/psicologia
18.
J Health Econ ; 33: 126-38, 2014 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-24316458

RESUMO

Social scientists continue to devote considerable attention to spillover effects for risky behaviors because of the important policy implications and the persistent challenges in identifying unbiased causal effects. We use the natural experiment of assigned college roommates to estimate peer effects for several measures of health risks: binge drinking, smoking, illicit drug use, gambling, having multiple sex partners, suicidal ideation, and non-suicidal self-injury. We find significant peer effects for binge drinking but little evidence of effects for other outcomes, although there is tentative evidence that peer effects for smoking may be positive among men and negative among women. In contrast to prior research, the peer effects for binge drinking are significant for all subgroups defined by sex and prior drinking status. We also find that pre-existing risky behaviors predict the closeness of friendships, which underscores the significance of addressing selection biases in studies of peer effects.


Assuntos
Grupo Associado , Assunção de Riscos , Adolescente , Consumo Excessivo de Bebidas Alcoólicas/etiologia , Consumo Excessivo de Bebidas Alcoólicas/psicologia , Coleta de Dados , Feminino , Amigos/psicologia , Jogo de Azar/etiologia , Jogo de Azar/psicologia , Habitação , Humanos , Masculino , Fatores Sexuais , Comportamento Sexual/psicologia , Fumar/psicologia , Estudantes/psicologia , Transtornos Relacionados ao Uso de Substâncias/etiologia , Transtornos Relacionados ao Uso de Substâncias/psicologia , Universidades
19.
Dev South Afr ; 31(6): 775-795, 2014 Nov 02.
Artigo em Inglês | MEDLINE | ID: mdl-25937697

RESUMO

This paper investigates household dissolution and changes in asset wealth (socio-economic position) in a rural South African community containing settled refugees. Survival analysis applied to a longitudinal dataset indicated that the covariates increasing the risk of forced household dissolution were a reduction in socio-economic position (asset wealth), adult deaths and the permanent outmigration of more than 40% of the household. Conversely, the risk of dissolution was reduced by bigger households, state grants and older household heads. Significant spatial clusters of former refugee villages also showed a higher risk of dissolution after 20 years of permanent residence. A discussion of the dynamics of dissolution showed how an outflow/inflow of household assets (socio-economic position) was precipitated by each of the selected covariates. The paper shows how an understanding of the dynamics of forced household dissolution, combined with the use of geo-spatial mapping, can inform inter-disciplinary policy in a rural community.

20.
Redox Biol ; 1: 566-77, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-24282679

RESUMO

Mammalian lipoxygenases play a role in normal cell development and differentiation but they have also been implicated in the pathogenesis of cardiovascular, hyperproliferative and neurodegenerative diseases. As lipid peroxidizing enzymes they are involved in the regulation of cellular redox homeostasis since they produce lipid hydroperoxides, which serve as an efficient source for free radicals. There are various epidemiological correlation studies relating naturally occurring variations in the six human lipoxygenase genes (SNPs or rare mutations) to the frequency for various diseases in these individuals, but for most of the described variations no functional data are available. Employing a combined bioinformatical and enzymological strategy, which included structural modeling and experimental site-directed mutagenesis, we systematically explored the structural and functional consequences of non-synonymous genetic variations in four different human lipoxygenase genes (ALOX5, ALOX12, ALOX15, and ALOX15B) that have been identified in the human 1000 genome project. Due to a lack of a functional expression system we resigned to analyze the functionality of genetic variations in the hALOX12B and hALOXE3 gene. We found that most of the frequent non-synonymous coding SNPs are located at the enzyme surface and hardly alter the enzyme functionality. In contrast, genetic variations which affect functional important amino acid residues or lead to truncated enzyme variations (nonsense mutations) are usually rare with a global allele frequency<0.1%. This data suggest that there appears to be an evolutionary pressure on the coding regions of the lipoxygenase genes preventing the accumulation of loss-of-function variations in the human population.


Assuntos
Lipoxigenase/química , Lipoxigenase/genética , Polimorfismo de Nucleotídeo Único , Códon sem Sentido , Evolução Molecular , Variação Genética , Humanos , Modelos Moleculares , Taxa de Mutação , Conformação Proteica
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA