372 research outputs found
Study of one-dimensional nature of (Sr,Ba)_2Cu(PO_4)_2 and BaCuP_2O_7 via 31P NMR
The magnetic behavior of the low-dimensional phosphates (Sr,Ba)_2 Cu(PO_4)_2
and BaCuP_2O_7 was investigated by means of magnetic susceptibility and ^{31}P
nuclear magnetic resonance (NMR) measurements. We present here the NMR shift
K(T), the spin-lattice 1/T_1 and spin-spin 1/T_2 relaxation-rate data over a
wide temperature range 0.02 K < T < 300 K. The T-dependence of the NMR K(T) is
well described by the S=1/2 Heisenberg antiferromagnetic chain model with an
intrachain exchange of J/k_B = 165 K, 151 K, and 108 K in Sr_2Cu(PO_4)_2,
Ba_2Cu(PO_4)_2, and BaCuP_2O_7, respectively. Our measurements suggest the
presence of magnetic ordering at 0.8 K in BaCuP_2O_7 (J/k_B = 108 K). For all
the samples, we find that 1/T_1 is nearly T-independent at low-temperatures (1
K < T < 10 K), which is theoretically expected for 1D chains when relaxation is
dominated by fluctuations of the staggered susceptibility. At high
temperatures, 1/T_1 varies nearly linearly with temperature
31P NMR study of Na2CuP2O7: a S=1/2 two-dimensional Heisenberg antiferromagnetic system
The magnetic properties of Na2CuP2O7 were investigated by means of 31P
nuclear magnetic resonance (NMR), magnetic susceptibility, and heat capacity
measurements. We report the 31P NMR shift, the spin-lattice 1/T1, and spin-spin
1/T2 relaxation-rate data as a function of temperature T.
The temperature dependence of the NMR shift K(T) is well described by the
S=1/2 square lattice Heisenberg antiferromagnetic (HAF) model with an
intraplanar exchange of J/k_B \simeq 18\pm2 K and a hyperfine coupling A =
(3533\pm185) Oe/mu_B. The 31P NMR spectrum was found to broaden abruptly below
T \sim 10 K signifying some kind of transition. However, no anomaly was noticed
in the bulk susceptibility data down to 1.8 K. The heat capacity appears to
have a weak maximum around 10 K. With decrease in temperatures, the
spin-lattice relaxation rate 1/T1 decreases monotonically and appears to agree
well with the high temperature series expansion expression for a S = 1/2 2D
square lattice.Comment: 12 pages, 8 figures, submitted to J. Phys.: Cond. Ma
Recommended from our members
Learning From Coalitions' Efforts to Promote Equity and Justice.
Coalitions and collaboratives are working to address many of the most pressing contemporary health and social issues. The articles in this special issue provide numerous insights into these complex collaborative processes across different contexts and focal issues. All emphasize and scrutinize the strategies that groups are using in their work. These strategies seek to navigate not only conventional notions of effectiveness but also the challenges of pursuing greater equity and justice. In this concluding article, we distill some of the key insights from these articles as a collective. This special issue on collaborating for equity and justice can serve as a launching point for new efforts by coalitions and researchers pursuing policy, systems, and structural changes, particularly those intent on addressing root causes of health and social disparities
Prevalence and predictors of home and automobile smoking bans and child environmental tobacco smoke exposure: a cross-sectional study of U.S.- and Mexico-born Hispanic women with young children
BACKGROUND: Detrimental effects of environmental tobacco smoke (ETS) exposure on child health are well documented. Because young children's primary exposure to ETS occurs in homes and automobiles, voluntary smoking restrictions can substantially reduce exposure. We assessed the prevalence of home and automobile smoking bans among U.S.- and Mexico-born Hispanics in the southwestern United States, and examined the influence of mother's country of birth and smoking practices on voluntary smoking bans and on child ETS exposure. METHODS: U.S.- and Mexico-born Hispanic mothers of children aged 2 through 12 years were systematically sampled from health clinics in Albuquerque, New Mexico. In-person interviews were conducted with 269 mothers (75.4% response rate) to obtain information on main study outcomes (complete versus no/partial home and automobile smoking bans; child room and automobile ETS exposure) and risk factors (mother's country of birth, maternal and household smoking behaviors). Data were analyzed with chi square tests and logistic regression models. RESULTS: Three-fourths (74–77%) of U.S.-born and 90–95% of Mexico-born mothers reported complete automobile and home smoking bans. In multivariate analyses, mother's U.S nativity, mother's current smoking, and presence of other adult smokers in the home were associated with significantly increased odds of not having a complete home or automobile smoking ban. Mother's smoking was associated with child ETS exposure both indoors (odds ratio [OR] = 3.31) and in automobiles (OR = 2.97). Children of U.S.-born mothers had increased odds of exposure to ETS indoors (OR = 3.24; 95% confidence interval [CI]: 1.37–7.69), but not in automobiles. Having complete smoking bans was associated with substantially reduced odds of child ETS exposure both indoors (OR = 0.10; 95% CI: 0.04–0.27) and in automobiles (OR = 0.14; 95% CI: 0.05–0.36). CONCLUSION: This study of Hispanic mothers in the southwestern U.S. indicates that there are substantial differences between U.S.- and Mexico-born mothers in the prevalence of home and automobile smoking bans, and resulting child ETS exposure. Tobacco interventions to increase smoke-free environments for U.S. Hispanic children should focus on both home and automobile smoking practices, especially among U.S.-born mothers, and utilize strategies that impact smoking practices of all household members
Knowledge, Attitudes, and Practices Regarding Smoke-Free Policies in Multi-Unit Housing in Georgia
Background: Nonsmokers living in multi-unit housing (MUH) without a smoke-free (SF) policy are vulnerable to secondhand and thirdhand smoke exposure. This study aimed to investigate the presence and type of SF policies in MUH in Georgia. Another aim was to explore knowledge, beliefs, and attitudes of property managers and owners (PM/Os) regarding SF MUH policies, including e-cigarettes.
Methods: Throughout 2015 PM/Os of MUH in Savannah and Atlanta were surveyed regarding SF policies in MUH. A list with contact information of PM/Os was obtained from the ASDE Survey Sampler. The participants were mailed an invitation letter and were called one week later to schedule the interview. To be eligible, the participant must have been an English-speaking adult working as a PM/O in MUH. The survey administered was adapted from a survey designed by CDC’s Office on Smoking and Health. All survey data were entered into SPSS and analyzed using SAS.
Results: The greatest number of the 91 PM/Os surveyed were female (70.3%) and/or white (48.4%), with an average age of 41.7 years. Most properties were market-rate (71.3%) or were a mix of market-rate and subsidized units (17.2%). Forty-one PM/Os reported some smoking restriction, while 50 had no policy. Properties mainly prohibited smoking in common outdoor areas (n=18) or inside individual apartments (n=13). Policies included bans of non-cigarette combustible products (n=19), hookah (n=12), e-cigarettes (n=7), and smokeless tobacco (n=5). Most PM/Os reported high compliance and positive resident reactions to the policy. Comparing responses by policy status, no differences in knowledge nor support for tobacco control legislation were found, except for SF outdoor seating in restaurants, which was more frequently supported by PM/Os with smoking restrictions. Personal beliefs on restricting use of cigarettes and e-cigarettes in MUH did not differ significantly by policy status, but those with a SF policy were more supportive of prohibiting smokeless tobacco use in MUH.
Conclusions: Implementing smoke-free policies in multi-unit housing is feasible and is generally supported by residents
A qualitative examination of home and neighborhood environments for obesity prevention in rural adults
<p>Abstract</p> <p>Background</p> <p>The home and neighborhood environments may be important in obesity prevention by virtue of food availability, food preparation, cues and opportunities for physical activity, and family support. To date, little research has examined how home and neighborhood environments in rural communities may support or hinder healthy eating and physical activity. This paper reports characteristics of rural homes and neighborhoods related to physical activity environments, availability of healthy foods, and family support for physical activity and maintaining an ideal body weight.</p> <p>Methods</p> <p>In-depth interviews were conducted with 60 African American and White adults over 50 years of age in two rural counties in Southwest Georgia. Interviews were transcribed verbatim and coded independently by two members of the research team using standard methods of qualitative analysis. Themes were then identified and data matrices were used to identify patterns by gender or race.</p> <p>Results</p> <p>Neighborhood features that supported physical activity were plenty of land, minimal traffic and living in a safe and friendly neighborhood. The major barrier was lack of recreational facilities. The majority of participants were not physically active with their family members due to schedule conflicts and lack of time. Family member-initiated efforts to encourage physical activity met with mixed results, with refusals, procrastination, and increased activity all reported. Participants generally reported it was easy to get healthy foods, although cost barriers and the need to drive to a larger town for a supermarket with good variety were noted as obstacles. Family conversations about weight had occurred for about half of the participants, with reactions ranging from agreement about the need to lose weight to frustration.</p> <p>Conclusion</p> <p>This study suggests that successful environmental change strategies to promote physical activity and healthy eating in rural neighborhoods may differ from those used in urban neighborhoods. The findings also provide insight into the complexities of family support for physical activity and maintaining a healthy weight. Addressing socio-ecologic factors has the potential to increase healthy behaviors and decrease the prevalence of obesity among rural residents.</p
Hearing aids do not alter cortical entrainment to speech at audible levels in mild-to-moderately hearing-impaired subjects
Background: Cortical entrainment to speech correlates with speech intelligibility and attention to a speech stream in noisy environments. However, there is a lack of data on whether cortical entrainment can help in evaluating hearing aid fittings for subjects with mild to moderate hearing loss. One particular problem that may arise is that hearing aids may alter the speech stimulus during (pre-)processing steps, which might alter cortical entrainment to the speech. Here, the effect of hearing aid processing on cortical entrainment to running speech in hearing impaired subjects was investigated.
Methodology: Seventeen native English-speaking subjects with mild-to-moderate hearing loss participated in the study. Hearing function and hearing aid fitting were evaluated using standard clinical procedures. Participants then listened to a 25-minute audiobook under aided and unaided conditions at 70 dB A sound pressure level (SPL) in quiet conditions. EEG data were collected using a 32-channel system. Cortical entrainment to speech was evaluated using decoders reconstructing the speech envelope from the EEG data. Null decoders, obtained from EEG and the time-reversed speech envelope, were used to assess the chance level reconstructions. Entrainment in the delta- (1-4 Hz) and theta- (4-8 Hz) band, as well as wideband (1-20 Hz) EEG data was investigated.
Results: Significant cortical responses could be detected for all but one subject in all three frequency bands under both aided and unaided conditions. However, no significant differences could be found between the two conditions in the number of responses detected, nor in the strength of cortical entrainment. The results show that the relatively small change in speech input provided by the hearing aid was not sufficient to elicit a detectable change in cortical entrainment.
Conclusion: For subjects with mild to moderate hearing loss, cortical entrainment to speech in quiet at an audible level is not affected by hearing aids. These results clear the pathway for exploring the potential to use cortical entrainment to running speech for evaluating hearing aid fitting at lower speech intensities (which could be inaudible when unaided), or using speech in noise conditions
Factors associated with support for smoke-free policies among government workers in six Chinese cities: a cross- sectional study
Background: A certain level of public support for smoke-free environments is a prerequisite for adoption and enforcement of policies and can be used as an indicator of readiness for legislative action. This study assessed support for comprehensive smoke-free policies in a range of settings such as hotels and colleges among government workers in China and identified factors associated with support for smoke-free policies. Understanding the extent to which government workers, a large segment of the working population in China, report a smoke-free workplace and support for smoke-free policies may be important indicators of readiness for strengthened policies given their role in formulating, implementing and enforcing regulations.
Methods: Data were from an evaluation of the Tobacco Free Cities initiative of Emory University’s Global Health Institute-China Tobacco Control Partnership. Self-administered surveys were completed by 6,646 workers in 160 government agencies in six Chinese cities. Multivariate logistic regression was used to identify factors associated with support for smoke-free worksites, bars, hotels, and colleges.
Results: Over half (54.6%) of participants were male. A large percentage of the male workers smoked (45.9%,) whereas very few women did (1.9%). Fewer than 50% of government workers reported smoke-free policies at work, with 19.0% reporting that smoking is allowed anywhere. Support for smoke-free policies was generally very high, with the lowest levels of support for smoke-free bars (79.0%) and hotels (82.3%), higher levels of support for restaurants (90.0%) and worksites (93.0%), and above 95% support for hospitals, schools, colleges, public transportation and religious settings. Knowledge of the harmfulness of secondhand smoke was positively associated with support for smoke-free policies. Stricter worksite smoking policies were associated with support for smoke-free workplaces and bars, but not hotels and colleges. Women and nonsmokers were more supportive of smoke-free policies in general.
Conclusion: Government workers play important roles in formulating, implementing and enforcing regulations; results suggest support for a more comprehensive approach to smoke-free environments in China among workers across a broad range of agencies
Pilot Study Results from a Brief Intervention to Create Smoke-Free Homes
Very few community-based intervention studies have examined how to effectively increase the adoption of smoke-free homes. A pilot study was conducted to test the feasibility, acceptability, and short-term outcomes of a brief, four-component intervention for promoting smoke-free home policies among low-income households. We recruited forty participants (20 smokers and 20 nonsmokers) to receive the intervention at two-week intervals. The design was a pretest-posttest with follow-up at two weeks after intervention. The primary outcome measure was self-reported presence of a total home smoking ban. At follow-up, 78% of participants reported having tried to establish a smoke-free rule in their home, with significantly more nonsmokers attempting a smoke-free home than smokers (P = .03). These attempts led to increased smoking restrictions, that is, going from no ban to a partial or total ban, or from a partial to a total ban, in 43% of the homes. At follow-up, 33% of the participants reported having made their home totally smoke-free. Additionally, smokers reported smoking fewer cigarettes per day. Results suggest that the intervention is promising and warrants a rigorous efficacy trial
- …