Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 52
Filtrar
1.
Front Psychol ; 15: 1298104, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38529096

RESUMO

Introduction: Managers assume a pivotal role during periods of organizational change, yet there exists a notable gap in our understanding of how their emotional exhaustion may impact their capacity to generate readiness to change within their teams. Grounded in the conservation of resources theory (COR), this study explores the crossover effect of managers' emotional exhaustion on team readiness to change. We expect this to occur through higher levels of laissez-faire leadership, which impacts the teams' psychological safety. Methodology: Data was gathered within a Canadian governmental organization undergoing two significant changes-cultural change and digitalization-with a specific focus on leadership as a pivotal factor in preparing teams for change. Employing surveys from 372 team members and 62 managers affected by this change, we conducted path analysis to empirically test the proposed model across 74 teams and their respective managers. Results: Managers' emotional exhaustion has a negative indirect effect on team readiness to change. The double mediation pathway implies a positive relationship on laissez-faire leadership, which hinders psychological safety. In turn, psychological safety hampers team readiness to change. Conclusion: Managers must invest significant resources to fulfill their roles and responsibilities during strategic change. Those who feel exhausted during change may look for ways to protect some of their resources by reducing the time and energy they invest leading their team. This self-preserving resource strategy has detrimental consequences on teams' effectiveness during change due to an indirect crossover effect that affects the levels of psychological safety on the team.

2.
Adm Sci Q ; 68(3): 601-647, 2023 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-37560020

RESUMO

Innovation teams must navigate inherent tensions between different learning activities to produce high levels of performance. Yet, we know little about how teams combine these activities-notably reflexive, experimental, vicarious, and contextual learning-most effectively over time. In this article, we integrate research on teamwork episodes with insights from music theory to develop a new theoretical perspective on team dynamics, which explains how team activities can produce harmony, dissonance, or rhythm in teamwork arrangements that lead to either positive or negative effects on overall performance. We first tested our theory in a field study using longitudinal data from 102 innovation teams at a Fortune Global 500 company; then, we replicated and elaborated our theory in a study of 61 MBA project teams at an elite North American university. Results show that some learning activities can occur within the same teamwork episode to have harmonious positive effects on team performance, while other activities combine to have dissonant negative effects when occurring in the same episode. We argue that dissonant activities must be spread across teamwork episodes to help teams achieve a positive rhythm of team learning over time. Our findings contribute to theory on team dynamics, team learning, and ambidexterity.

3.
Phys Chem Chem Phys ; 25(29): 20015-20025, 2023 Jul 26.
Artigo em Inglês | MEDLINE | ID: mdl-37461994

RESUMO

This work investigates the mixed site occupancy of aluminium and silicon atoms in the ß-AlFeSi phase. For this purpose, the six mixed Al/Si sites of the ß-AlFeSi structure were considered independent and alternatively substituted by Al or Si, thus generating 64 ordered structures or end-members. The enthalpy of formation of each end-member was calculated by DFT. These calculations allowed us to derive the enthalpy of mixing of the solid solution at 0 K, over a wide range of chemical compositions, from the Al-Fe binary system to the Si-Fe binary system. In addition, the heat capacities of the solid solution were determined using a Debye model based on the calculation of the elastic constants and the equation of state of each end-member. These heat capacity values were used along with the enthalpy of formation we calculated to determine the Gibbs free energies of all the end-members of the ß-AlFeSi structure. Finally, the configurational entropy of mixing from the Compound Energy Formalism (CEF) for the configurational entropy of mixing was subsequently used to calculate the occupation fractions of the Si sites on the Al sites of the ß-AlFeSi structure, at 300 K and 938 K, the latter being the thermal decomposition temperature of this compound. These original site occupancy data were used to quantify the chemical ordering of the solid solution and to compare different sublattice (SL) models. We thus highlight that the SL model of the ß-AlFeSi solution most commonly accepted in the literature generates considerable errors in its thermodynamic description, contrary to the model proposed in this paper, which is both simple and particularly accurate, consisting in merging the sites Al(1)-Al(6), the sites Al(2)-Al(3) as well as the sites Al(4)-Al(5).

4.
Phys Chem Chem Phys ; 25(15): 10866-10884, 2023 Apr 12.
Artigo em Inglês | MEDLINE | ID: mdl-37013718

RESUMO

Classical molecular dynamics simulations of metallic systems have been extensively applied in recent years for the exploration of the energetic behavior of mesoscale structures and for the generation of thermodynamic and physical properties. The evaluation of the conditions leading to the melting of pure metals and alloys is particularly challenging as it involves at one point the simultaneous presence of both a solid and a liquid phase. Defects such as vacancies, dislocation, grain boundaries and pores typically promote the melting of a solid by locally increasing its free energy which favors the destruction of long-range ordering at the origin of this phase transition. In real materials, many of these defects are microscopic and cannot yet be modelled via conventional atomistic simulations. Still, molecular dynamics-based methodologies are commonly used to estimate the melting temperature of solids. These methods involve the use of mesoscale supercells with various nanoscale defects. Moreover, the deterministic nature of classical MD simulations requires the adequate selection of the initial configuration to be melted. In this context, the main objective of this paper is to quantify the precision of the existing classical molecular dynamics computational methods used to evaluate the melting point of pure compounds as well as the solidus/liquidus lines of Al-based binary metallic systems. We also aim to improve the methodology of different approaches such as the void method, the interface method as well as the grain method to obtain a precise evaluation of the melting behavior of pure metals and alloys. We carefully analyzed the importance of the local chemical ordering on the melting behavior. The ins and outs of different numerical methods in predicting the melting temperature via MD are discussed through several examples related to pure metallic elements, congruently and non-congruently melting compounds as well as binary solid solutions. It is shown that the defect distribution of the initial supercell configuration plays an important role upon the description of the melting mechanism of solids leading to a poor predictive capability of melting temperature if not properly controlled. A new methodology based on defect distribution within the initial configuration is proposed to overcome these limitations.

5.
Ann Behav Med ; 57(10): 836-845, 2023 09 13.
Artigo em Inglês | MEDLINE | ID: mdl-37061829

RESUMO

OBJECTIVE: Postpartum weight retention is associated with adverse health among both civilian and military women. PURPOSE: The current study evaluated a stepped-care weight management intervention, Moms Fit 2 Fight, adapted for use in a pregnant and postpartum military population. METHODS: Active duty women and other TRICARE beneficiaries (N = 430) were randomized to one of three conditions: gestational weight gain only (GWG-only) intervention (n =144), postpartum weight loss only (PPWL-only) intervention (n =142), or a combined GWG + PPWL intervention (n = 144). Those participants who received the PPWL intervention (i.e., the PPWL-only and GWG+PPWL conditions) were combined consistently with the pre-registered protocol and compared to those participants who did not receive the PPWL intervention in the primary analyses. Primary outcome data (i.e., postpartum weight retention) were obtained at 6-months postpartum by unblinded data collectors, and intent-to-treat analyses were conducted. RESULTS: Retention at 6-months postpartum was 88.4%. Participants who received the PPWL intervention retained marginally less weight (1.31 kg) compared to participants that received the GWG-only intervention (2.39 kg), with a difference of 1.08 kg (p = .07). None of the measured covariates, including breastfeeding status, were significantly associated with postpartum weight retention. Of the participants who received the PPWL intervention, 48.1% participants returned to their pre-pregnancy weight at 6-months postpartum, with no significant differences compared to those who received the GWG-only intervention. CONCLUSIONS: A behavioral intervention targeting diet and physical activity during the postpartum period had a trend for reduced postpartum weight retention. CLINICAL TRIAL INFORMATION: The trial is registered on clinicaltrials.gov (NCT03057808).


Since postpartum weight retention is associated with negative health outcomes among women in the military and women in the general population, the Moms Fit 2 Fight study evaluated a stepped-care weight management intervention among active duty women and other military health insurance beneficiaries. Participants (N = 430) were recruited in their first trimester of pregnancy and randomized to one of three conditions: pregnancy weight gain-only intervention, postpartum weight loss (PPWL)-only intervention, or a combined pregnancy weight gain and PPWL intervention. Participants who received the PPWL intervention (i.e., the participants who received the PPWL-only intervention or the combined intervention) were compared to the participants who did not receive the PPWL intervention, based on weight retention at 6-months postpartum. Participants who received the PPWL intervention retained marginally less weight compared to participants that did not receive the PPWL intervention. Thus, this behavioral intervention targeting diet and physical activity during the postpartum period had a trend for reducing postpartum weight retention, which may be beneficial for achieving military fitness standards and avoiding escalating obesity over multiple pregnancies.


Assuntos
Ganho de Peso na Gestação , Militares , Complicações na Gravidez , Gravidez , Feminino , Humanos , Obesidade/epidemiologia , Estilo de Vida , Período Pós-Parto , Redução de Peso , Sobrepeso , Índice de Massa Corporal
6.
MRS Energy Sustain ; 9(2): 212-247, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36569468

RESUMO

Abstract: Metals and alloys are among the most technologically important materials for our industrialized societies. They are the most common structural materials used in cars, airplanes and buildings, and constitute the technological core of most electronic devices. They allow the transportation of energy over great distances and are exploited in critical parts of renewable energy technologies. Even though primary metal production industries are mature and operate optimized pyrometallurgical processes, they extensively rely on cheap and abundant carbonaceous reactants (fossil fuels, coke), require high power heating units (which are also typically powered by fossil fuels) to calcine, roast, smelt and refine, and they generate many output streams with high residual energy content. Many unit operations also generate hazardous gaseous species on top of large CO2 emissions which require gas-scrubbing and capture strategies for the future. Therefore, there are still many opportunities to lower the environmental footprint of key pyrometallurgical operations. This paper explores the possibility to use greener reactants such as bio-fuels, bio-char, hydrogen and ammonia in different pyrometallurgical units. It also identifies all recycled streams that are available (such as steel and aluminum scraps, electronic waste and Li-ion batteries) as well as the technological challenges associated with their integration in primary metal processes. A complete discussion about the alternatives to carbon-based reduction is constructed around the use of hydrogen, metallo-reduction as well as inert anode electrometallurgy. The review work is completed with an overview of the different approaches to use renewable energies and valorize residual heat in pyrometallurgical units. Finally, strategies to mitigate environmental impacts of pyrometallurgical operations such as CO2 capture utilization and storage as well as gas scrubbing technologies are detailed. This original review paper brings together for the first time all potential strategies and efforts that could be deployed in the future to decrease the environmental footprint of the pyrometallurgical industry. It is primarily intended to favour collaborative work and establish synergies between academia, the pyrometallurgical industry, decision-makers and equipment providers. Highlights: A more sustainable production of metals using greener reactants, green electricity or carbon capture is possible and sometimes already underway. More investments and pressure are required to hasten change. Discussion: Is there enough pressure on the aluminum and steel industries to meet the set climate targets?The greenhouse gas emissions of existing facilities can often be partly mitigated by retrofitting them with green technologies, should we close plants prematurely to build new plants using greener technologies?Since green or renewable resources presently have limited availability, in which sector should we use them to maximize their benefits?

7.
Health Psychol Behav Med ; 10(1): 956-972, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36210867

RESUMO

Background: Behavioral weight loss programs often prescribe physical activity (PA) goals in terms of minutes/week of moderate-to-vigorous PA (MVPA) and steps/day. However, the impact of meeting each type of goal prescription on weight loss is unclear, particularly in digitally-based (eHealth/mHealth) programs. This secondary analysis of a randomized trial examined the effects of meeting steps-based and minutes-based goals on weight loss in an eHealth behavioral weight control program. Methods: Adults in the control arm received a 6-month online behavioral weight loss intervention with prescribed weekly goals for daily steps and minutes of MVPA. The number of weeks steps-based and minutes-based goals were met (≥100% and ≥75% thresholds) based on self-reported PA were examined as predictors of 6-month weight loss among those providing weight outcomes (n = 172; 81% of control arm) using a systems regression approach. Results: Participants (BMI 35.6 kg/m2; 90.1% female; 48.7 years of age) met weekly goals for MVPA (7.1 ± 6.4 weeks) more often than steps (3.5 ± 5.5 weeks, P < .001). Meeting the steps goals (ß = .24, P < .001) and MVPA goals (ß = .20, P < .001) were each statistically significant predictors of weight loss at the 100% threshold; their total effects were not statistically different from one another (χ 2 = 1.12, P = .29). Similarly, at the 75% threshold for steps goals (ß = .19, P < .001) and MVPA goals (ß = .19, P < .001), each independently predicted weight loss; no differences were detected in their total effects (χ2 = .01, P = .92). The probability of reaching ≥5% weight loss was comparable between meeting the steps goals and MVPA goals at both adherence thresholds. Conclusions: Greater attainment of PA goals prescribed as steps and minutes of MVPA independently contribute to similar weight loss outcomes in a 6-month online behavioral weight loss intervention. Future research should determine whether promoting adherence to combined steps-based and minutes-based goals produces better weight loss than utilizing either goal alone and identify strategies that improve adherence.

8.
Phys Chem Chem Phys ; 24(37): 22605-22623, 2022 Sep 28.
Artigo em Inglês | MEDLINE | ID: mdl-36102884

RESUMO

Multi-component and multiphasic materials are continually being developed for electronics, aircraft, automotive, and general applications. Integrated Computational Materials Engineering (ICME) is a multiple-length scale approach that greatly benefits from atomistic scale simulations to explore new alloys. Molecular Dynamics (MD) allows to perform large-scale simulations by using classical interatomic potentials. The main challenge of using such a classical approach is the transferability of the interatomic potentials from one structure to another when one aims to study multi-component systems. In this work, the reliability of Zr, Al-Cu, Al-Cr and Al-Zr-Ti force field potentials is examined. It has been found that current interatomic potentials are not completely transferable due to the structure dependence from their parameterization. Besides that, they provide an appropriate description of unary and binary systems, notably for liquids, isotropic solids, and partially isotropic compounds. For solidification purposes, it has been found that coherent primary solidification of the FCC-phase in pure Al is highly dependent on the formalism to tune interatomic interactions. For Al-Cr alloys, the icosahedral short-range ordering (ISRO) increased by adding Cr to the melts. The different steps of solidification (formation of nuclei, effective germination of the α-Al phase and end of solidification) have been related to the evolution of the ISRO. The addition of Cr in melts prevented undercooling via icosahedral-enhanced nucleation of the α-Al phase. Precipitation of primary intermetallics in hyper-peritectic Al-Cr alloys was also tested. Contrary to classical thermodynamics predictions, α-Al phase was the primary precipitate for these alloys. This implies that Cr supersaturated the α-Al phase rather than forming intermetallic phases due to the high cooling rates.

9.
Obes Sci Pract ; 8(4): 401-410, 2022 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-35949285

RESUMO

Objective: Dietary self-monitoring is consistently related to both short- and long-term weight loss, but typically declines over time. Adopting an abbreviated approach to self-monitoring might reduce burden and potentially increase engagement while maintaining efficacy. Methods: Using a Delphi-type study, experts were queried about abbreviated self-monitoring approaches that might best balance efficacy and burden and asked to identify when these approaches might best be implemented within a behavioral weight loss program. Experts were surveyed three times until consensus was reached. Results: Experts identified three main categories of promising strategies for abbreviated self-monitoring regardless of whether individuals have been successful with weight loss or full dietary self-monitoring: (1) self-weighing only, (2) reducing the foods/beverages self-monitored to those that are often less routine and higher in caloric density, and (3) reducing the number of days per week to engage in full dietary self-monitoring. Experts recommended transitioning to abbreviated self-monitoring after 2 weeks of no self-monitoring among individuals who were struggling and after reaching 5%-10% weight loss among successful individuals. Conclusions: These expert opinions offer a foundation to experimentally manipulate promising strategies for reducing burden and increasing long-term engagement in self-monitoring, with a goal of enhancing long-term weight control.

10.
Obes Sci Pract ; 8(4): 433-441, 2022 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-35949286

RESUMO

Objective: Weight control programs that incorporate group sessions produce greater weight losses, but this has not been explored in the context of online programs. Further, counselor-crafted self-monitoring feedback is a core element of lifestyle interventions, although pre-scripted, modular feedback which does not require detailed counselor review may adequately promote weight loss. The current study explored the weight losses achieved in an online program that included facilitated group sessions, as well as outcomes when counselor-crafted self-monitoring feedback was provided. Methods: A 2 × 2 pilot factorial randomized participants (90% women) with overweight/obesity (N = 73) to facilitated group sessions (yes/no) and type of feedback (counselor-crafted/pre-scripted, modular) within a 16-week online behavioral weight control program. Weight change outcomes were collected digitally. Treatment engagement and intervention delivery time were also tracked. Results: Individuals offered weekly facilitated online group sessions lost more weight (-5.3% ± 4.9%) than those receiving the same digital program without group sessions (-3.1% ± 4.0%; p = 0.04). Those receiving group sessions also demonstrated significantly greater treatment engagement. Individuals receiving pre-scripted, modular feedback lost significantly more weight (-5.3% ± 4.8%) than those receiving the more traditional counselor-crafted feedback (-3.1% ± 4.1%; p = 0.04), but treatment engagement did not differ between conditions. However, interventionist time required to provide feedback was markedly lower for pre-scripted than counselor-crafted feedback (1.4 vs. 3.5 h per participant over 16 weeks, respectively, p = 0.01). Conclusions: Incorporating weekly facilitated online group sessions significantly increased weight losses achieved in a digital lifestyle program. Further, pre-scripted, modular feedback required significantly less staff time than counselor-crafted feedback without diminishing weight losses. Thus, group sessions and pre-scripted feedback warrant consideration when designing digital lifestyle programs.

11.
Obesity (Silver Spring) ; 30(10): 1951-1962, 2022 10.
Artigo em Inglês | MEDLINE | ID: mdl-36041980

RESUMO

OBJECTIVE: Despite military fitness regulations, women in the military frequently experience overweight/obesity, excessive gestational weight gain (GWG), and the postpartum implications. This interim analysis of the Moms Fit 2 Fight study examines GWG outcomes among active-duty personnel and other TRICARE beneficiaries who received a stepped-care GWG intervention compared with those who did not receive a GWG intervention. METHOD: Participants (N = 430; 32% identified with an underrepresented racial group, 47% were active duty) were randomized to receive a GWG intervention or the comparison condition, which did not receive a GWG intervention. RESULTS: Retention was 88% at 32 to 36 weeks' gestation. Participants who received the GWG intervention gained less weight compared with those who did not (mean [SD] = 10.38 [4.58] vs. 11.80 [4.87] kg, p = 0.0056). Participants who received the intervention were less likely to have excessive GWG compared with those who did not (54.6% vs. 66.7%, p = 0.0241). The intervention effects were significant for participants who identified as White, but not for those of other racial identities. There were no significant differences between the conditions in maternal/neonatal outcomes. CONCLUSIONS: The intervention successfully reduced excessive GWG, particularly among participants who identified as White. Should this intervention be found cost-effective, it may be sustainably integrated throughout the military prenatal care system.


Assuntos
Ganho de Peso na Gestação , Militares , Complicações na Gravidez , Índice de Massa Corporal , Feminino , Humanos , Recém-Nascido , Obesidade , Sobrepeso/prevenção & controle , Gravidez , Complicações na Gravidez/prevenção & controle , Aumento de Peso
12.
Am J Health Promot ; 36(6): 996-1004, 2022 07.
Artigo em Inglês | MEDLINE | ID: mdl-35377246

RESUMO

PURPOSE: Financial incentives are a promising approach to enhance weight loss outcomes; however, little guidance exists on the optimal incentive structure. DESIGN: Mixed methods. SETTING: An online weight management trial, combining outcome (i.e., weight loss) and behavioral (i.e., self-weighing, dietary self-monitoring, and steps) incentives over 12 months (up to $665). SUBJECTS: 116 participants who completed the incentive preference assessment at the 18-month follow-up visit. METHOD: Response distributions on the form, magnitude, certainty, and target of the incentives and content analysis of the qualitative responses. RESULTS: Nearly all (96.6%) participants indicated they liked receiving electronic Amazon gift cards, more so than the alternatives presented. Most participants (81.0%) thought they would have lost a similar amount of weight if the incentives were smaller. Few (18.1%) indicated they would have preferred a lottery structure, but 50.8% indicated the variable incentive schedule was beneficial during the maintenance period. Most (77.6%) felt incentives were most helpful when starting to lose weight. In both phases, most participants (85.3% and 72.4%, respectively) indicated appropriate behaviors were incentivized. Participants had mixed views on whether outcome or behavioral incentives were most motivating. CONCLUSION: There was notable variation in preferences for the magnitude, duration, and timing of incentives; it will be important to examine in future research whether incentive design should be tailored to individual preferences.


Assuntos
Programas de Redução de Peso , Humanos , Intervenção Baseada em Internet , Motivação , Redução de Peso , Programas de Redução de Peso/métodos
13.
J Allergy Clin Immunol Pract ; 10(6): 1577-1586.e3, 2022 06.
Artigo em Inglês | MEDLINE | ID: mdl-35304842

RESUMO

BACKGROUND: Weight loss might improve asthma control in people with obesity. However, people with asthma might have particular challenges losing weight and the amount of weight loss needed to improve asthma control is not clear. OBJECTIVES: To pilot-test an online weight loss intervention and to estimate the impact of weight loss on asthma control. METHODS: We performed a 6-month, single-arm, futility trial of an online weight loss intervention at 2 centers. To reject the assumption of futility, 9 or more participants had to lose at least 5% of their body weight. We also assessed the association between weight loss (≥5%) and asthma outcomes. RESULTS: Forty-three participants (85% women) started the weight loss intervention. The median and interquartile range for the body mass index was 40.3 kg/m2 (range 34.7-46.8 kg/m2), and 14 (range 12-17 kg/m2) for the Asthma Control Test score. At 6 months, 10 participants (23%; 95% CI 12%-39%) lost at least 5% of their initial weight. Weight loss of at least 5% was associated with a clinically and statistically significant improvements in their Asthma Control Test (median [interquartile range] increase of 3 [1 to 7]; P < .05), Marks Asthma Quality of Life Score (-9.5 [-18 to -3]; P = .008), and their general health-related quality of life score (RAND-36; improved by 9.4 [2.8 to 22.5]; P =.014). CONCLUSIONS: An online weight loss intervention has the potential to meet U.S. Food and Drug Administration guidance for product evaluation (at least a 5% weight loss in 35% of people) for treating obesity, and is associated with a clinically significant improvement in asthma control, quality of life, and overall health-related quality of life.


Assuntos
Asma , Obesidade , Asma/complicações , Índice de Massa Corporal , Feminino , Humanos , Intervenção Baseada em Internet , Masculino , Obesidade/terapia , Qualidade de Vida , Redução de Peso , Programas de Redução de Peso
14.
J Med Internet Res ; 24(1): e30673, 2022 01 28.
Artigo em Inglês | MEDLINE | ID: mdl-35089159

RESUMO

BACKGROUND: Standard behavioral weight loss interventions often set uniform physical activity (PA) goals and promote PA self-monitoring; however, adherence remains a challenge, and recommendations may not accommodate all individuals. Identifying patterns of PA goal attainment and self-monitoring behavior will offer a deeper understanding of how individuals adhere to different types of commonly prescribed PA recommendations (ie, minutes of moderate-to-vigorous physical activity [MVPA] and daily steps) and guide future recommendations for improved intervention effectiveness. OBJECTIVE: This study examined weekly patterns of adherence to step-based and minute-based PA goals and self-monitoring behavior during a 6-month online behavioral weight loss intervention. METHODS: Participants were prescribed weekly PA goals for steps (7000-10,000 steps/day) and minutes of MVPA (50-200 minutes/week) as part of a lifestyle program. Goals gradually increased during the initial 2 months, followed by 4 months of fixed goals. PA was self-reported daily on the study website. For each week, participants were categorized as adherent if they self-monitored their PA and met the program PA goal, suboptimally adherent if they self-monitored but did not meet the program goal, or nonadherent if they did not self-monitor. The probability of transitioning into a less adherent status was examined using multinomial logistic regression. RESULTS: Participants (N=212) were predominantly middle-aged females with obesity, and 67 (31.6%) self-identified as a racial/ethnic minority. Initially, 73 (34.4%) participants were categorized as adherent to step-based goals, with 110 [51.9%] suboptimally adherent and 29 [13.7%] nonadherent, and there was a high probability of either remaining suboptimally adherent from week to week or transitioning to a nonadherent status. However, 149 (70.3%) participants started out adherent to minute-based goals (34 [16%] suboptimally adherent and 29 [13.7%] nonadherent), with suboptimally adherent seen as the most variable status. During the graded goal phase, participants were more likely to transition to a less adherent status for minute-based goals (odds ratio [OR] 1.39, 95% CI 1.31-1.48) compared to step-based goals (OR 1.24, 95% CI 1.17-1.30); however, no differences were seen during the fixed goal phase (minute-based goals: OR 1.06, 95% CI 1.05-1.08; step-based goals: OR 1.07, 95% CI 1.05-1.08). CONCLUSIONS: States of vulnerability to poor PA adherence can emerge rapidly and early in obesity treatment. There is a window of opportunity within the initial 2 months to bring more people toward adherent behavior, especially those who fail to meet the prescribed goals but engage in self-monitoring. Although this study describes the probability of adhering to step- and minute-based targets, it will be prudent to determine how individual characteristics and contextual states relate to these behavioral patterns, which can inform how best to adapt interventions. TRIAL REGISTRATION: ClinicalTrials.gov NCT02688621; https://clinicaltrials.gov/ct2/show/NCT02688621.


Assuntos
Etnicidade , Objetivos , Exercício Físico , Feminino , Humanos , Pessoa de Meia-Idade , Grupos Minoritários , Redução de Peso
15.
Obesity (Silver Spring) ; 30(1): 106-116, 2022 01.
Artigo em Inglês | MEDLINE | ID: mdl-34932889

RESUMO

OBJECTIVE: This study examined the impact of a financial incentive scheme integrating process and outcome incentives across weight-loss induction and weight maintenance on 18-month weight outcomes. METHODS: This was a randomized controlled trial. Participants with overweight or obesity (n = 418; 91% female; 28% racial/ethnic minority) were randomized to an 18-month, online, group-based behavioral weight-control program (Internet-Only) or the same program with financial incentives provided for 12 months, contingent on self-regulatory weight-control behaviors (self-weighing, dietary self-monitoring, and physical activity) and weight-outcome benchmarks (Internet+Incentives). No financial incentives were provided from Months 13 to 18 to examine the durability of weight-control behaviors and outcomes without incentives. RESULTS: Weight-loss induction at Month 6 was significantly greater for Internet+Incentives than Internet-Only (6.8% vs. 4.9%, respectively, p = 0.01). Individuals receiving incentives were significantly more likely to maintain weight loss ≥ 5% at Month 12 (45% in Internet+Incentives vs. 32% in Internet-Only, p < 0.02) and remain weight stable (39% vs. 27%, respectively, p < 0.01). Internet+Incentives participants also reported significantly greater behavioral engagement through Month 12. However, once incentives ceased, there were no differences in sustained weight outcomes (Month 18), and engagement declined dramatically. CONCLUSIONS: Despite promoting greater treatment engagement and initial weight loss, financial incentives as offered in this study did not promote better extended weight control.


Assuntos
Motivação , Programas de Redução de Peso , Etnicidade , Feminino , Humanos , Masculino , Grupos Minoritários , Redução de Peso
16.
Obes Sci Pract ; 7(6): 682-689, 2021 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-34877007

RESUMO

OBJECTIVE: There is a high prevalence of obesity in people with asthma, and obesity is associated with poorly controlled asthma. Significant weight loss might improve asthma control: the purpose of this study was to investigate patient characteristics and factors that might affect implementation of a weight loss and/or roflumilast intervention, to target both obesity and asthma. METHODS: A cross-sectional study of people with obesity and poorly controlled asthma performed at 13 sites across the United States. RESULTS: One hundred and two people participated in this study. Median BMI was 37 (IQR 35-42). The majority, 55%, were African American and 76% were female. Fifty two percent had very poorly controlled asthma. Most participants were quite sedentary (70% reported being inactive or participating only in light-intensity activities according to the Stanford Brief Activity Survey). Participants reported significant impairments related to physical function on the Impact of Weight on Quality of Life-Lite questionnaire (median score 67 [IQR 41-84]). Thirty-five percent of participants reported mild, and 2 % moderate, depressive symptoms as assessed by the Patient Health Questionnaire-9. CONCLUSIONS: Poorly controlled asthma and obesity often affect minority populations and are associated with significant impairments in health related to physical function and low levels of physical activity that might complicate efforts to lose weight. Interventions targeted at poorly controlled asthma associated with obesity in the United States need to address factors complicating health in underserved communities, such as increasing opportunities for physical activity, while also managing activity limitations related to the combination of asthma and obesity.

17.
Transl Behav Med ; 11(12): 2164-2173, 2021 12 14.
Artigo em Inglês | MEDLINE | ID: mdl-34662410

RESUMO

Physical activity (PA) goal adherence is consistently associated with greater weight loss during behavioral obesity treatment, and early weight loss response predicts future weight loss success. However, it remains unclear which behaviors during the initial weeks of treatment distinguish responders from nonresponders and might be effective targets for improving treatment outcomes. To characterize subgroups with distinct patterns of PA goal adherence during the initial 2 months of an online, group-based weight control program and determine associations between these patterns and 6-month weight loss. Participants received an online behavioral obesity intervention with PA goals and daily self-monitoring. Weekly adherence to step goals and moderate-to-vigorous PA (MVPA) minute goals based on self-monitoring records were examined using latent class analysis. Body weight was objectively measured at 0, 2, and 6 months. Participants (N = 212; 91.5% female, 31.6% race/ethnic minority, mean body mass index: 35.8 ± 5.9 kg/m2) clustered into three subgroups based on early goal attainment: "Both PA Goals," "MVPA Goals Only," and "Neither PA Goal." The "Both PA Goals" class had significantly greater 6-month weight loss (estimated mean weight loss [95% CI]: -9.4% [7.4 to 11.5]) compared to the "MVPA Goals Only" (-4.8% [3.4 to 6.1]) and "Neither PA Goal" classes (-2.5% [1.4 to 3.6]). Individuals meeting both PA goals early in treatment achieve greater weight losses than those meeting MVPA but not step goals, pointing to the need to explore factors associated with nonadherence to each of the PA goals to better understand these potential targets for treatment refinement and adaptive interventions.


This study is the first to characterize subgroups of individuals engaged in a behavioral weight control program with distinct patterns of early physical activity (PA) goal attainment. These early PA patterns emerged as a novel factor associated with subsequent weight loss and provide an important lens to view early treatment engagement. The greatest weight losses were seen in the subgroup likely to meet program goals for both weekly minutes of moderate-to-vigorous PA and daily steps. Understanding the factors associated with PA goal attainment during the initial 2 months of a behavioral weight control program may provide insights that will allow early identification of likely treatment success and detect individuals at risk for reduced weight losses, which could signal individuals for whom additional or different support may then be directed to increase weight loss success.


Assuntos
Etnicidade , Objetivos , Exercício Físico , Feminino , Humanos , Análise de Classes Latentes , Masculino , Grupos Minoritários , Obesidade/terapia , Redução de Peso
18.
Nutrients ; 13(5)2021 May 14.
Artigo em Inglês | MEDLINE | ID: mdl-34069308

RESUMO

Many college students struggle to cook frequently, which has implications for their diet quality and health. Students' ability to plan, procure, and prepare food (food agency) may be an important target for shifting the college student diet away from instant and inexpensive staples like packaged ramen. The randomized intervention study included two sequential cooking interventions: (1) six weeks of cooking classes based in food agency pedagogy held once per week, and (2) six weekly home delivered meal kits (3 meals per kit) to improve food agency, diet quality, and at home cooking frequency of college students. Based on availability and subsequent randomization, participants were assigned to one of four conditions that included active cooking classes, meal kit provision, or no intervention. Participants who took part in the cooking intervention had significant improvement in food agency immediately following the intervention period. Participants who did not participate in cooking classes and only received meal kits experienced significant, though less pronounced, improvement in food agency scores following the meal kit provision. Neither intervention improved diet quality or routinely improved cooking frequency. Active cooking classes may improve food agency of college students, though further research is needed to determine how this may translate into improved diet quality and increased cooking frequency.


Assuntos
Culinária , Dieta Saudável , Dieta , Alimentos , Adulto , Feminino , Preferências Alimentares , Humanos , Masculino , Estudantes , Universidades , Adulto Jovem
19.
Phys Chem Chem Phys ; 23(2): 733-752, 2021 Jan 21.
Artigo em Inglês | MEDLINE | ID: mdl-33427279

RESUMO

As the field of ionic liquids matures to more industrially implemented applications, robust models of their physico-chemical properties become necessary for process optimization. Viscosity is a particularly difficult property to model since there is no generally accepted theory for the viscosity of liquids. This paper aims to review the viscosity models developed or adapted to ionic liquids and their mixtures that are available in the literature. The scope of application and limitations of these models are discussed. In particular, the mixing rules' current formalism for ionic liquids is analysed in light of established knowledge from the inorganic molten salt community.

20.
Nutrients ; 12(12)2020 Nov 28.
Artigo em Inglês | MEDLINE | ID: mdl-33260523

RESUMO

Americans are cooking fewer meals at home and eating more convenience foods prepared elsewhere. Cooking at home is associated with higher quality diets, while a reduction in cooking may be associated with increases in obesity and risk factors for chronic disease. The aims of this study were to examine cooking as an intervention for weight control in overweight and obese adults, and whether such an intervention increases participants' food agency and diet quality. Overweight and obese adults were randomized into one of two intervention conditions: active or demonstration. Both conditions received the same 24-week behavioral weight loss intervention, and bi-weekly cooking classes. The active condition prepared a weekly meal during a hands-on lesson, while the demonstration condition observed a chef prepare the same meal. The active condition lost significantly more weight at six months compared with the demonstration condition (7.3% vs. 4.5%). Both conditions saw significant improvements in food agency scores and Healthy Eating Index scores, though no significant differences were noted between groups. The addition of active cooking to a weight management intervention may improve weight loss outcomes, though benefits in diet quality and cooking behaviors may also be seen with the addition of a demonstration-only cooking intervention.


Assuntos
Culinária/métodos , Dieta/normas , Sobrepeso/terapia , Programas de Redução de Peso , Adulto , Terapia Comportamental , Feminino , Humanos , Masculino
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA