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1.
Subst Use Misuse ; 59(10): 1546-1555, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38831657

RESUMO

Background: College students continue to report problematic alcohol use. To mitigate adverse outcomes, recent studies have employed harm reduction strategies known as Protective Behavioral Strategies (PBS). Deviance Regulation Theory (DRT), an impression management intervention, has been used to promote the use of PBS. DRT relies on impression management to modify behavior. This may be especially important for individuals with higher levels of trait narcissism. Method: College student drinkers (n = 132) were randomly assigned to receive a positive message about PBS users, a negative message about non-PBS users, or control. Participants reported on current PBS use norms, daily alcohol use, PBS use, and any alcohol-related problems experienced during the previous week for the next 10 weeks. Results: Data were analyzed using multilevel regression to examine PBS use across time by condition. When PBS norms were low, narcissism was strongly associated with lower rates of PBS use in the control group. If individuals received a positive or negative message, the association between narcissism and PBS use was diminished, among individuals with low PBS norms. There were no significant differences at mean or high levels of norms, indicating the messaging was only important for the highest risk group (i.e., those with low PBS norms). Discussion: The results of this study suggest that message framing may be effective at reducing the robust negative association between narcissism and PBS use for individuals with low PBS norms. Positive messages about individuals that use PBS may be one approach to mitigating problematic alcohol consumption in this at-risk group.


Assuntos
Consumo de Álcool na Faculdade , Redução do Dano , Narcisismo , Estudantes , Humanos , Masculino , Feminino , Adulto Jovem , Estudantes/psicologia , Universidades , Consumo de Álcool na Faculdade/psicologia , Adolescente , Consumo de Bebidas Alcoólicas/psicologia , Adulto , Teoria Psicológica
2.
J Synchrotron Radiat ; 31(Pt 4): 877-887, 2024 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-38771778

RESUMO

Nanoscale structural and electronic heterogeneities are prevalent in condensed matter physics. Investigating these heterogeneities in 3D has become an important task for understanding material properties. To provide a tool to unravel the connection between nanoscale heterogeneity and macroscopic emergent properties in magnetic materials, scanning transmission X-ray microscopy (STXM) is combined with X-ray magnetic circular dichroism. A vector tomography algorithm has been developed to reconstruct the full 3D magnetic vector field without any prior noise assumptions or knowledge about the sample. Two tomographic scans around the vertical axis are acquired on single-crystalline Nd2Fe14B pillars tilted at two different angles, with 2D STXM projections recorded using a focused 120 nm X-ray beam with left and right circular polarization. Image alignment and iterative registration have been implemented based on the 2D STXM projections for the two tilts. Dichroic projections obtained from difference images are used for the tomographic reconstruction to obtain the 3D magnetization distribution at the nanoscale.

3.
Vet Parasitol ; 327: 110140, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38330532

RESUMO

We evaluated the effect of 4 anthelmintic treatments on the viability of Trichinella spiralis encysted muscle larvae (ML) 55 days post infection (PI) in experimentally infected pigs. Muscle larvae were isolated from pig muscle by artificial digestion after oral treatment of pigs with Levamisole (8 mg/kg, daily for 5 days) and Mebendazole (50 mg/kg, daily for 5 days); Doramectin (0.3 mg/kg, single IM injection), and Moxidectin (0.5 mg/kg, single pour on). Isolated larvae from treated pigs were orally inoculated into mice to assess viability of ML from each treatment. Only Mebendazole treatment of pigs significantly reduced ML viability in mice. The effect of timing of the effective Mebendazole treatment on ML from a longer term infection was then examined in a second experiment. Analysis revealed that Mebendazole treatment of pigs with 250 mg/kg over 3 days (83 mg/kg/day) or 5 days (50 mg/kg/day) reduced numbers of ML recovered from pig tissues compared to untreated, infected controls, and rendered ML non-infective to mice; Mebendazole treatment of pigs with 250 mg/kg in a single dose was not effective in reducing ML numbers recovered from pigs or in impacting ML infectivity to mice. An examination of the lowest effective dose of Mebendazole on encysted ML was determined in a third experiment. Mebendazole of pigs with 5, 50, or 100 mg/kg over 3 days demonstrated that 5 or 50 mg/kg over 3 days insufficient to reduce infectivity in recovered ML, while 100 mg/kg (and 83 g from experiment 2) over 3 days significantly reduces infectivity of ML. This procedure provides a means to evaluate the efficacy of various anthelmintic treatments on the viability of Trichinella spiralis ML in pig tissues, and identified Mebendazole, at 83-100 mg/kg administered over a 3-5 day period as an anthelmintic which renders encysted Trichinella spiralis ML from pig tissues non-infective. As risk from Trichinella significantly impacts acceptance of pork from pasture-raised pigs, these data provide a method, especially for producers of these high-risk pigs, to eliminate the potential of Trichinella transmission from infected pork.


Assuntos
Anti-Helmínticos , Doenças dos Roedores , Trichinella spiralis , Trichinella , Triquinelose , Suínos , Camundongos , Animais , Mebendazol/farmacologia , Mebendazol/uso terapêutico , Triquinelose/tratamento farmacológico , Triquinelose/veterinária , Triquinelose/diagnóstico , Larva , Músculos , Anti-Helmínticos/farmacologia , Anti-Helmínticos/uso terapêutico , Doenças dos Roedores/tratamento farmacológico
4.
J Vet Intern Med ; 37(5): 1830-1838, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37555741

RESUMO

BACKGROUND: Many dog owners alter their dog's nutritional regimen after a diagnosis of cancer. There are limited data as to specific changes made and reasons behind these changes. HYPOTHESIS/OBJECTIVES: To collect updated and detailed data on changes made by owners to their dog's diet and supplements after a cancer diagnosis. ANIMALS: Responses were collected from a survey of dog owners who brought their dogs to the UC Davis Veterinary Medical Teaching Hospital's Oncology Service for the first time after a cancer diagnosis. Dogs with recurrence or presenting for a second type of cancer were excluded. METHODS: Eligible owners were surveyed between December 2020 and March 2022. The survey contained 62 questions regarding diet, supplement use, and treats, and how these were altered after a cancer diagnosis. Responses were matched to medical record data. RESULTS: One hundred twenty-eight surveys were retained for analysis, including 120 respondents that completed the survey. In response to a cancer diagnosis, 54.8% (95% CI; 45.7%-63.8%) of owners altered diets or supplements or both. The most common informational resource for dog diets was veterinarians (53.9%). Usage of home-prepared foods significantly increased after a cancer diagnosis (P = .03). There was no significant difference in commercial diet usage before or after a diagnosis (P = .25). Joint support products were the most common supplements given both before (37.4%) and after (35.0%) diagnosis. CONCLUSIONS AND CLINICAL IMPORTANCE: Many dog owners alter their dog's nutritional intake after a cancer diagnosis. These owners should be provided information relating to commonly observed alterations, including home-prepared foods and supplements.


Assuntos
Doenças do Cão , Neoplasias , Médicos Veterinários , Cães , Animais , Humanos , Suplementos Nutricionais , Dieta/veterinária , Inquéritos e Questionários , Neoplasias/veterinária
5.
Eat Behav ; 49: 101732, 2023 04.
Artigo em Inglês | MEDLINE | ID: mdl-37146412

RESUMO

Loss-of-control eating (LOCE) is highly prevalent in college students and may be driven by enduring personality traits. Narcissism is often conceptualized with two broad domains: grandiose and vulnerable. The association between narcissism and LOCE has not been directly assessed, nor the potential influence of emotion regulation deficits, which are differentially associated with grandiosity and vulnerability. This study hypothesized an association between vulnerable narcissism and LOCE in college students by way of emotion regulation difficulties, extending prior findings. Participants (n = 704) completed a survey on pathological eating and body image disturbance, emotion regulation difficulties, and narcissistic traits. Results supported a full mediation effect, such that vulnerable narcissism was positively associated with LOCE by way of emotion regulation difficulties. Present findings suggest the mechanism primarily predictive of LOCE is emotion regulation difficulties, and predisposition to deficits in emotion regulation associated with vulnerable narcissism may increase the odds of LOCE. Additionally, it was noted that grandiose narcissism evinced a fully mediated inverse association with LOCE. Clinical implications and directions for future research are discussed.


Assuntos
Regulação Emocional , Humanos , Inquéritos e Questionários , Narcisismo , Estudantes/psicologia
6.
Psychiatry ; 86(1): 1-16, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-36240071

RESUMO

Objective: Alcohol use continues to be prevalent and problematic among young adult samples. Protective behavioral strategies (PBS), which are harm reduction strategies utilized while drinking, have been linked to decreased alcohol use and subsequent alcohol-related problems. An individual's likelihood of adopting PBS and other health behaviors, according to The Health Belief Model (HBM), is dependent on perceived susceptibility to and severity of adverse health outcomes, as well as perceived benefits and barriers related to implementing those behaviors. The present study examined whether the perceived effectiveness of PBS in the context of the HBM leads to an increase in PBS use. Method: The analytic sample (n =694 college students, Mage =20.21, SD =4.37, 63.26% female, 72.05% Caucasian) self-reported demographics, weekly alcohol consumption (i.e., frequency, intensity, and quantity), alcohol-related problems, use of PBS, and perceived effectiveness of PBS use. A latent variable model was used to test the effect of perceived PBS effectiveness on PBS use, alcohol consumption, and alcohol-related problems. Results: Perceived PBS effectiveness was associated with a higher likelihood of using PBS subtypes (Manner of Drinking, Stopping/Limiting Drinking, and Serious Harm Reduction), which in turn was associated with reductions in alcohol consumption and problems. Conclusions: These findings suggest that increasing perceptions of PBS effectiveness may lead to more PBS use, decreased alcohol consumption, and fewer alcohol-related problems. Future research could implement longitudinal methodology to assess attempts to increase perceived effectiveness of PBS use and potentially establish a causal link between these perceptions, PBS use, and alcohol-related outcomes.


Assuntos
Consumo de Bebidas Alcoólicas , Transtornos Relacionados ao Uso de Álcool , Adulto Jovem , Humanos , Feminino , Adulto , Masculino , Consumo de Bebidas Alcoólicas/epidemiologia , Etanol , Redução do Dano , Autorrelato , Modelo de Crenças de Saúde
7.
ACS Nano ; 16(10): 17257-17262, 2022 Oct 25.
Artigo em Inglês | MEDLINE | ID: mdl-36153944

RESUMO

Superconducting thin films of niobium have been extensively employed in transmon qubit architectures. Although these architectures have demonstrated improvements in recent years, further improvements in performance through materials engineering will aid in large-scale deployment. Here, we use information retrieved from secondary ion mass spectrometry and electron microscopy to conduct a detailed assessment of the surface oxide that forms in ambient conditions for transmon test qubit devices patterned from a niobium film. We observe that this oxide exhibits a varying stoichiometry with NbO and NbO2 found closer to the niobium film/oxide interface and Nb2O5 found closer to the surface. In terms of structural analysis, we find that the Nb2O5 region is semicrystalline in nature and exhibits randomly oriented grains on the order of 1-3 nm corresponding to monoclinic N-Nb2O5 that are dispersed throughout an amorphous matrix. Using fluctuation electron microscopy, we are able to map the relative crystallinity in the Nb2O5 region with nanometer spatial resolution. Through this correlative method, we observe that the highly disordered regions are more likely to contain oxygen vacancies and exhibit weaker bonds between the niobium and oxygen atoms. Based on these findings, we expect that oxygen vacancies likely serve as a decoherence mechanism in quantum systems.

8.
Psychiatry ; 85(3): 293-307, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35349398

RESUMO

Objective: The most common conceptualization of psychopathy is a two-factor model of primary psychopathy and secondary psychopathy. Primary psychopathy consists of interpersonally abusive behavior, and callousness. Secondary psychopathy includes impulsive and risky decision making. Past research has found that psychopathy is related to negative outcomes, including increased alcohol consumption and problems, and is inversely related to harm reduction behaviors. Protective behavioral strategies (PBS), behaviors designed to reduce alcohol consumption and associated problems, may mediate the relationship between psychopathy and alcohol pathology. The current study examined the relationship between psychopathy, each subtype of PBS use (serious harm reduction (SHR), manner of drinking (MD) and stopping/limiting drinking (SLD)), alcohol consumption, and alcohol problems.Method: Participants were n = 967 (61.22% female) college students. Participants completed measures assessing psychopathy, PBS use, alcohol consumption, and alcohol problems. A path analysis was conducted to examine the relationships between psychopathy, subtypes of PBS, and alcohol consumption and problems.Results: Results indicated an inverse relationship between primary psychopathy and both SHR PBS and MD PBS, while secondary psychopathy was inversely associated with all three PBS subtypes. SHR PBS was inversely associated with alcohol problems while MD PBS was inversely associated with alcohol consumption.Conclusion: These findings suggest specific PBS subtypes mediate the relationship between primary and secondary psychopathy and alcohol consumption and problems. It may be clinically pertinent to consider targeting PBS use, such as with motivational interviewing, when working with patients exhibiting psychopathy traits. Future research should consider these findings when examining alcohol use.


Assuntos
Transtornos Relacionados ao Uso de Álcool , Estudantes , Consumo de Bebidas Alcoólicas/epidemiologia , Transtornos Relacionados ao Uso de Álcool/epidemiologia , Feminino , Redução do Dano , Humanos , Masculino , Universidades
9.
Nutrients ; 14(2)2022 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-35057551

RESUMO

Sweetness drives the consumption of added sugars, so understanding how to best measure sweet hedonics is important for developing strategies to lower sugar intake. However, methods to assess hedonic response to sweetness vary, making results across studies difficult to integrate. We compared methods to measure optimal sucrose concentration in 21 healthy adults (1) using paired-comparison preference tracking vs. ratings of liking, (2) with participants in the laboratory vs. at home, and (3) using aqueous solutions vs. vanilla milk. Tests were replicated on separate days to assess test-retest reliability. Test-retest reliability was similar between laboratory and home testing, but tended to be better for vanilla milk and preference tracking. Optimal sucrose concentration was virtually identical between laboratory and home, slightly lower when estimated via preference tracking, and about 50% lower in vanilla milk. However, optimal sucrose concentration correlated strongly between methods, locations, and stimuli. More than 50% of the variability in optimal sucrose concentration could be attributed to consistent differences among individuals, while much less variability was attributable to differences between methods. These results demonstrate convergent validity between methods, support testing at home, and suggest that aqueous solutions can be useful proxies for some commonly consumed beverages for measuring individual differences.


Assuntos
Bebidas , Preferências Alimentares , Edulcorantes , Paladar , Adulto , Animais , Feminino , Humanos , Individualidade , Masculino , Pessoa de Meia-Idade , Leite , Filosofia , Reprodutibilidade dos Testes , Projetos de Pesquisa , Sacarose/análise , Adulto Jovem
10.
Psychol Rep ; 125(5): 2384-2399, 2022 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34080886

RESUMO

BACKGROUND: Psychopathy has been an increasing area of clinical and personality research and is associated with numerous problematic outcomes, including pathological gambling, though this area of research is limited. The most common conceptualization of psychopathy is a two-factor model of primary and secondary psychopathy, with primary psychopathy comprising more interpersonal traits and secondary psychopathy encompassing more antisocial behaviors. Previous research has linked psychopathy to greater urgency and lower utilization of harm reduction strategies. OBJECTIVES: The current study examines the relationship between primary psychopathy, secondary psychopathy, and problematic gambling, as well as the possible mechanisms of these relationships. METHOD: College student gamblers (n = 308) completed surveys on psychopathy, impulsivity, protective behavioral strategies regarding gambling, and possible gambling problems. RESULTS: Primary psychopathy was inversely related to gambling protective behavioral strategies (PBS) and secondary psychopathy was positively associated with higher levels of urgency. Secondary psychopathy, via urgency, was a strong predictor of whether an individual will experience gambling problems, while primary psychopathy via PBS better predicts the number of gambling problems one experiences. CONCLUSION: This study extends an overall under-researched area of gambling and personality and highlights the importance of delineating different factors of psychopathy regarding problematic gambling outcomes.


Assuntos
Jogo de Azar , Transtorno da Personalidade Antissocial , Humanos , Comportamento Impulsivo , Personalidade , Estudantes
11.
Psychol Addict Behav ; 36(6): 619-634, 2022 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34591518

RESUMO

OBJECTIVE: First-time-in-college (FTIC) students are relatively inexperienced with alcohol and have pressure to assimilate to new norms, and, therefore, are at a heightened risk of alcohol-related consequences. The present study investigates the use of a brief deviance regulation theory (DRT) intervention to increase the use of protective behavioral strategies (PBS) among FTIC students. METHOD: Participation took place completely online. Participants were first-year college students (n = 147, Mage = 18.11, 77.68% female) at a large southwest U.S. university. Participants were randomly assigned one of three conditions: (a) a positive message about individuals who use PBS, (b) a negative message about individuals who do not use PBS, or (c) an assessment-only control group. Participants then completed weekly assessments for 5 weeks, examining alcohol use and consequences, PBS use, and perceived PBS norms. Contrasting previous research, the present study investigated weekly effects of the intervention. In addition, norm type (quantity vs. frequency) was examined as moderators of intervention messaging. RESULTS: Across conditions, both quantity and frequency norms increased over time. The positive message produced immediate and lasting effects on SLD PBS among those with higher (+ 1 SD) frequency norms. The intervention effects for the negative message, using the quantity norm, grew across time on all PBS. CONCLUSIONS: These results provide initial support for the use of a DRT prevention program for FTIC students. Negative messages may promote long-term PBS use, while positive messages may be most effective in addressing immediate and lasting changes in the use of alcohol protective strategies. (PsycInfo Database Record (c) 2022 APA, all rights reserved).


Assuntos
Consumo de Álcool na Faculdade , Consumo de Bebidas Alcoólicas/prevenção & controle , Etanol , Feminino , Humanos , Masculino , Estudantes , Universidades
12.
Exp Clin Psychopharmacol ; 29(3): 236-250, 2021 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-34264735

RESUMO

Harm reduction is a framework that places substance use on a spectrum from total abstinence to continued controlled use. Protective behavioral strategies (PBS) are a set of individually implemented harm reduction strategies that have shown to reduce the rate of use and severity of consequences from risky behaviors. Previous research has shown that PBS use effectively reduces negative consequences. The present study provides an overview of the literature on PBS measures for various risk behaviors, and common interventions used in conjunction with PBS. Of the articles reviewed, 15 validated PBS measures were found and eight distinct categories of PBS interventions. The 15 measures reviewed included risk factors such as alcohol use/consequences (n = 8), dating and sexual behaviors (n = 4), gambling (n = 1), cannabis (n = 1), and condom use (n = 1). A survey of the literature produced eight distinct categories of interventions with varying degrees of effectiveness: (a) Brief Motivational Interventions, (b) Personalized Normative Feedback, (c) PBS Skills Training, (d) PBS Instruction, (e) Deviance Regulation Theory Interventions, (f) Behavioral Economic Based Interventions, (g) Counterfactual Thinking and (h) Episodic Future Thinking. Findings from the present study corroborate the notion that PBS effectively reduce negative consequences associated with behaviors, such as negative alcohol-related consequences, harmful cannabis use, and adverse sexual outcomes. Research on interventions targeting PBS is lacking in areas outside of alcohol use. Within alcohol use, the utility of interventions varies widely. Understanding the reason for this discrepancy is an important area for future research. (PsycInfo Database Record (c) 2021 APA, all rights reserved).


Assuntos
Alcoolismo/prevenção & controle , Jogo de Azar/prevenção & controle , Redução do Dano , Abuso de Maconha/prevenção & controle , Sexo sem Proteção/prevenção & controle , Adulto , Humanos , Masculino , Fatores de Risco
13.
J Parasitol ; 107(3): 404-410, 2021 05 01.
Artigo em Inglês | MEDLINE | ID: mdl-34010426

RESUMO

Foodborne pathogens continue to pose a public health risk and can cause serious illness and outbreaks of disease in consumers. The consumption of raw or undercooked infected meat, such as pork containing infectious stages of Toxoplasma gondii, may be a major route of transmission to humans. Given the occasional presence of T. gondii in pork meat and the frequent use of pork for products not intended to be cooked, such as dry-cured ham, a potential risk exists for T. gondii transmission to consumers of these products. The purpose of this study was to determine the seroprevalence of T. gondii in U.S. market hogs and sows at slaughter. A total of 20,209 sera samples collected from 22 U.S. slaughterhouses, including 15 of the top 25 largest slaughter plants in the United States, were tested for T. gondii antibodies using a commercial ELISA assay. Seroprevalence in this study was 0.74%, with a herd prevalence of 10.86%. We compared seroprevalence of T. gondii in market hogs vs. sows from a separate but geographically similar set of slaughterhouse locations, with serum samples screened using the T. gondii modified agglutination test. This set of market hogs demonstrated 0% seroprevalence for T. gondii, while sows from geographically similar but separate slaughter facilities demonstrated a seroprevalence of 1.03%. Overall, both analyses show low seroprevalence of T. gondii in U.S market hogs and sows, respectively, and a marked drop in prevalence in market hogs and sows compared to previous studies.


Assuntos
Doenças dos Suínos/epidemiologia , Doenças dos Suínos/parasitologia , Toxoplasmose Animal/epidemiologia , Matadouros , Animais , Anticorpos Antiprotozoários/sangue , Ensaio de Imunoadsorção Enzimática/veterinária , Feminino , Masculino , Estudos Soroepidemiológicos , Suínos , Toxoplasma/imunologia , Estados Unidos/epidemiologia
14.
PLoS One ; 16(3): e0248746, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33765070

RESUMO

In insect-pollinated crops, gene flow is affected by numerous factors including crop characteristics, mating system, life history, pollinators, and planting management practices. Previous studies have concentrated on the impact of distance between genetically engineered (GE) and conventional fields on adventitious presence (AP) which represents the unwanted presence of a GE gene. Variables other than distance, however, may affect AP. In addition, some AP is often present in the parent seed lots used to establish conventional fields. To identify variables that influence the proportion of AP in conventional alfalfa fields, we performed variable selection regression analyses. Analyses based on a sample-level and a field-level analysis gave similar, though not identical results. For the sample-level model, distance from the GE field explained 66% of the variance in AP, confirming its importance in affecting AP. The area of GE fields within the pollinator foraging range explained an additional 30% of the variation in AP in the model. The density of alfalfa leafcutting bee domiciles influenced AP in both models. To minimize AP in conventional alfalfa seed fields, management practices should focus on optimizing isolation distances while also considering the size of the GE pollen pool within the pollinator foraging range, and the foraging behavior of pollinators.


Assuntos
Produtos Agrícolas/genética , Medicago sativa/genética , Plantas Geneticamente Modificadas/genética , Animais , Fluxo Gênico , Insetos/fisiologia , Polinização , Washington
15.
J Health Psychol ; 26(4): 556-566, 2021 03.
Artigo em Inglês | MEDLINE | ID: mdl-30678500

RESUMO

Difficulties in emotion regulation are an important theoretical construct implicated in the maintenance of loss of control eating. In this study, 45 community and college participants who reported loss of control eating at least once per week carried tablets for 2 weeks, responding to random assessments throughout each day. We compared trajectories of emotion regulation abilities before and after loss of control eating episodes (using average loss of control eating episode time to divide non-loss-of-control eating days). Emotion regulation abilities remained stable on non-loss-of-control eating days, but there was a significant increase in emotion regulation difficulties after loss of control eating episodes. These results suggest that increases in emotion regulation difficulties are not responsible for initiation of loss of control eating.


Assuntos
Regulação Emocional , Emoções , Humanos , Universidades
16.
Alcohol Clin Exp Res ; 44(12): 2598-2610, 2020 12.
Artigo em Inglês | MEDLINE | ID: mdl-33206419

RESUMO

BACKGROUND: Alcohol misuse continues to be a significant public health problem. Understanding the factors that may contribute to the harmful progression in drinking is an important aspect of public health. Previous research has shown that affect regulation is associated with problematic alcohol use. Additionally, emotion instability has been found as a predictor of alcohol-related problems and may be linked to reinforcement mechanisms. METHODS: The current study examined positive mood, negative mood, and mood instability in real time across drinking and nondrinking days utilizing ecological momentary assessment (EMA). Current drinkers (n = 74) were recruited for a 21-day EMA study. Participants completed up to 10 random assessments of positive mood, negative mood, and alcohol use per day. Mood instability was assessed as the squared difference in current mood from mood in the previous assessment. Data were analyzed using piecewise multilevel regression to examine mood trajectories across drinking and nondrinking days. RESULTS: Positive emotion across the day was higher on drinking days than nondrinking days and continued to increase after drinking initiation. In contrast, negative emotion across the day was lower on drinking days than nondrinking days and continued to decrease after drinking initiation. Emotional functioning was stable across the day on nondrinking days. However, on drinking days there was a steady increase in emotional instability leading up to drinking initiation, followed by a rapid stabilization after initiation. CONCLUSIONS: This study highlights the potentially reinforcing impact of alcohol via emotional stability. Overall, these findings highlight the importance of mood dynamics when examining the reinforcing effects of alcohol consumption.


Assuntos
Abstinência de Álcool/psicologia , Consumo de Bebidas Alcoólicas/psicologia , Emoções/efeitos dos fármacos , Adolescente , Adulto , Afeto/efeitos dos fármacos , Feminino , Humanos , Masculino , Adulto Jovem
17.
Phys Rev Lett ; 125(19): 195503, 2020 Nov 06.
Artigo em Inglês | MEDLINE | ID: mdl-33216596

RESUMO

We report the laser-induced solid-state transformation between a periodic "approximant" and quasicrystal in the Al-Cr system during rapid quenching. Dynamic transmission electron microscopy allows us to capture in situ the dendritic growth of the metastable quasicrystals. The formation of dendrites during solid-state transformation is a rare phenomenon, which we attribute to the structural similarity between the two intermetallics. Through ab initio molecular dynamics simulations, we identify the dominant structural motif to be a 13-atom icosahedral cluster transcending the phases of matter.

18.
Nano Lett ; 20(7): 4731-4738, 2020 Jul 08.
Artigo em Inglês | MEDLINE | ID: mdl-32202799

RESUMO

Real-space topological magnetic structures such as skyrmions and merons are promising candidates for information storage and transport. However, the microscopic mechanisms that control their formation and evolution are still unclear. Here, using in situ Lorentz transmission electron microscopy, we demonstrate that skyrmion crystals (SkXs) can nucleate, grow, and evolve from the conical phase in the same ways that real nanocrystals form from vapors or solutions. More intriguingly, individual skyrmions can also "reproduce" by division in a mitosis-like process that allows them to annihilate SkX lattice imperfections, which is not available to crystals made of mass-conserving particles. Combined string method and micromagnetic calculations show that competition between repulsive and attractive interactions between skyrmions governs particle-like SkX growth, but nonconservative SkX growth appears to be defect mediated. Our results provide insights toward manipulating magnetic topological states by applying established crystal growth theory, adapted to account for the new process of skyrmion mitosis.

19.
ACS Comb Sci ; 22(5): 248-254, 2020 05 11.
Artigo em Inglês | MEDLINE | ID: mdl-32207918

RESUMO

Additive manufacturing synthesis using laser engineered net shaping (LENS) is utilized to rapidly print libraries of mischmetal (MM = La, Ce, Nd, and Pr) containing R2TM14B alloys (R = MM + separated Nd and TM = Fe and Co) enabling robust evaluation of physical properties over a wide composition range. High-throughput characterization of the magnetic and thermal properties are used to identify compositions for potential high-temperature, high-performance permanent magnets with reduced critical rare-earth elements. Improved Curie temperature (Tc ∼ 450 °C) is obtained with substitution of Fe by Co in pseudoternary R2TM14B alloys. Furthermore, a 4-fold decrease in the Nd content can be achieved through substitution with less critical Ce- and La-rich MM, while retaining high Tc. Guided by the properties of the LENS printed samples, selected compositions with and without TiC additions are synthesized via melt-spinning techniques to produce nanostructured ribbons. The maximum room temperature coercivity (Hc) and energy product ((BH)max) without TiC are found to be 5.8 kOe, 8.5 MGOe, respectively, while TiC additions as a grain refiner gave Hc and (BH)max of 4.9 kOe, 9.8 MGOe, respectively. Structural characterization of the melt-spun ribbons shows homogeneous grain refinement with TiC additions, which leads to an increase in the energy product.


Assuntos
Ligas/química , Boro/química , Cobalto/química , Ensaios de Triagem em Larga Escala , Ferro/química , Metais Terras Raras/química , Fenômenos Magnéticos , Tamanho da Partícula
20.
Sci Rep ; 10(1): 1981, 2020 Feb 06.
Artigo em Inglês | MEDLINE | ID: mdl-32029753

RESUMO

Laser powder bed fusion (LPBF) is a method of additive manufacturing characterized by the rapid scanning of a high powered laser over a thin bed of metallic powder to create a single layer, which may then be built upon to form larger structures. Much of the melting, resolidification, and subsequent cooling take place at much higher rates and with much higher thermal gradients than in traditional metallurgical processes, with much of this occurring below the surface. We have used in situ high speed X-ray diffraction to extract subsurface cooling rates following resolidification from the melt and above the ß-transus in titanium alloy Ti-6Al-4V. We observe an inverse relationship with laser power and bulk cooling rates. The measured cooling rates are seen to correlate to the level of residual strain borne by the minority ß-Ti phase with increased strain at slower cooling rates. The α-Ti phase shows a lattice contraction which is invariant with cooling rate. We also observe a broadening of the diffraction peaks which is greater for the ß-Ti phase at slower cooling rates and a change in the relative phase fraction following LPBF. These results provide a direct measure of the subsurface thermal history and demonstrate its importance to the ultimate quality of additively manufactured materials.

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