Longitudinal impact of leisure-time physical activity on pain intensity and daily activity limitation in people with low back pain. Findings from the PAMPA cohort.

OBJECTIVE: We aimed to prospectively evaluate the association between leisure-time physical activity and outcomes related to low back pain (LBP), such as pain intensity and daily activity limitation. METHODS: We analyzed data from the PAMPA (Prospective Study about Mental and Physical Health) cohort, a longitudinal study with adults residing in Southern Brazil. Participants answered an online-based, self-administered questionnaire. Physical activity was assessed as minutes per week, and those who reported engaging in 150 min/week or more were considered active. We also assessed the types of activities participants engaged. Pain intensity was assessed with a numeric pain rating scale (from 0 to 10), and participants reported whether their pain restricted their daily activities. Generalized linear models were used to investigate the association between physical activity and LBP outcomes. RESULTS: Data from 991 individuals (82.7% women) aged 38.9 ± 13.9 were analyzed. Pain intensity was higher in those inactive in waves one (ß: 0.54; 95 % CI 0.23, 0.86), three (ß: 0.38; 95% CI 0.02, 0.75), and four (ß: 0.48; 95% CI 0.06, 0.90). Also, being physically inactive at wave one was associated with a higher probability of daily activity limitation at waves two (IRR 1.77; 95% CI 1.27; 2.46), three (IRR 1.63; 95% CI 1.17, 2.29), and four (IRR 1.73; 95% CI 1.20, 2.50). CONCLUSION: Not practicing at least 150 min/week of physical activity resulted in higher levels of pain and an increased risk of daily activity limitation in individuals with LBP. Moreover, various forms of activities have shown to be advantageous in alleviating pain among this group.

Care seek behavior for low back pain in southern Brazil during the COVID-19 pandemic: a panel data analysis.

BACKGROUND: During the COVID-19 pandemic, people with low back pain (LBP) might have avoided seeking care for their pain. We aimed to investigate how the COVID-19 pandemic has affected LBP care seeking behavior among adults. METHODS: Data from four assessments of the PAMPA cohort were analyzed. Participants who reported experiencing LBP during wave one both before and during social restrictions (n = 1,753 and n = 1,712, respectively), wave two (n = 2,009), and wave three (n = 2,482) were included. We asked participants about sociodemographic, behavioral, and health factors and outcomes related to LBP. Poisson regression analyses were conducted, and data are presented as prevalence ratios (PR) and respective 95% confidence interval (95%CI). RESULTS: Overall, care seeking behavior decreased by half in the first months of restrictions, from 51.5% to 25.2%. Although there was an increase in care seeking behavior observed in the other two assessments (nearly 10 and 16 months after restrictions), it was insufficient to reach pre-pandemic levels. In the first months of restrictions, a similar scenario was observed for specific care, such as general practitioner and exercise professional care, with proportions of pre-pandemic levels reached after 10 and 16 months. Women were more likely to seek care for LBP 10 and 16 months after restrictions (PR 1.30 95%CI 1.11; 1.52, PR 1.22 95%CI 1.06; 1.39, respectively). Also, those participants who worked, were physically active, and reported pain-related disability and high pain levels were more likely to seek care at all time points assessed. CONCLUSION: Overall, care-seeking behavior for LBP significantly decreased in the first months of restrictions and increased in the following months; however, this behavior remained lower than pre-pandemic levels.

Short-term impact of COVID-19 pandemic on low back pain: data from the PAMPA Cohort, Brazil.

BACKGROUND: To evaluate the short-term impact of COVID-19 pandemic on low back pain (LBP) outcomes in southern Brazil. METHODS: Data from the PAMPA Cohort were analyzed. Adults were recruited between June and July 2020 in the Rio Grande do Sul state using online-based strategies. Participants responded a self-reported, online questionnaire on LBP with two timepoints: before (retrospectively) and during COVID-19 pandemic. We assessed LBP experience, LBP-related activity limitation (no/yes), and LBP intensity (0 to 10 [strongest pain]). RESULTS: From a total sample of 2,321 respondents (mean age: 37.6 ± 13.5; 75.4% women), the prevalence of LBP did not change significantly from before (74.7% [95%CI 72.3; 76.9]) to the first months of pandemic (74.2% [95%CI 71.9; 76.3]). However, an increased pain levels (ß: 0.40; 95%CI 0.22; 0.58) and a higher likelihood for activity limitation due to LBP was observed (PR 1.14; 95%CI 1.01; 1.29). Longitudinal analyzes showed that age, gender, BMI, chronic diseases, physical activity, and anxiety and depression symptoms, were associated with LBP in the first pandemic months. CONCLUSION: Although the prevalence of LBP did not change at the first months of COVID-19 pandemic, LBP-induced impairment in daily activities and pain intensity was higher when compared to before the pandemic.

Chronic low back pain prevalence in Federal Highway Police Officers: A cross-sectional study.

BACKGROUND: Police officers are exposed to specific occupational tasks, which require lifting, trunk flexion and rotation, carrying weight, and frequent standing periods, which may be associated with an increased risk of experiencing low back pain (LBP). OBJECTIVE: To describe the prevalence and intensity of chronic LBP (CLBP) in Brazilian Federal Highway Police officers (FHPO) from the Rio Grande do Sul state and evaluate its associated factors. METHODS: A total of 208 FHPOs participated in this study. The participants answered an electronic questionnaire containing sociodemographic, behavioral, and occupational questions, and CLBP history. Data analysis comprises descriptive statistics and Poisson regression models. RESULTS: Most of the FHPO were male, aged 41 or more, lived with a partner and were physically active. Sixty-seven percent of FHPO had CLBP, and the median pain intensity was 3.0 (IQR = 0- 5). Participants who lived with a partner were less likely to report CLBP (PR = 0.80; 95% CI = 0.64; 0.99). On the other hand, those who worked as FHPO for more than 11 years were more likely to report CLPB (PR = 1.32; 95% CI = 1.06; 1.63), and high pain intensity (ß= 0.95; 95% CI = 0.19; 1.71). CONCLUSIONS: The high CLBP prevalence among FHPO from Rio Grande do Sul state indicates a need to highlight the importance for police organizations to promote CLBP prevention and implement workplace management programs.

Physical activity and the incidence of depression during the COVID-19 pandemic in Brazil: Findings from the PAMPA cohort.

We examined the longitudinal association between physical activity (PA) and the incidence of self-reported diagnosed depression in adults in southern Brazil during the COVID-19 pandemic. Data from the PAMPA (Prospective Study About Mental and Physical Health) cohort was used. Data collection for baseline was carried out on June-July 2020, with two follow-up assessments taking place six months apart. An online, self-reported questionnaire assessed depression and PA. Depression was assessed by asking participants whether they were ever diagnosed with depression. We included 441 participants (women: 75.9%; mean age [SD]: 38.0 [13.5]) in southern Brazil. Over the follow-up, 21.8% (95% confidence interval [CI]: 18.1%-25.9%) were diagnosed with depression. Insufficiently active (<150 min per week of physical activity) (Incidence rate [IR]: 61.9; 95%CI: 39.5-102.4; p = 0.047) and active (≥150 min per week of physical activity) (IR: 50.4; 95%CI: 31.9-84.0; p = 0.015) participants had reduced IR of depression per 1000 persons-year at risk compared to inactive ones (0 min per week of physical activity) (IR: 99.9; 95%CI: 79.7-126.8). In the adjusted analyses, participants in the insufficient active (hazard ratio [HR]: 0.58; 95%CI: 0.34-0.98) and active (HR: 0.53; 95%CI: 0.31-0.93) group had a lower risk of developing depression than the inactive group. PA both at and out of home reduced the risk of incident depression (HR: 0.49; 95%CI: 0.25-0.98) compared to no physical activity. Endurance (HR: 0.52; 95%CI: 0.28-0.97) and endurance plus strengthening (HR: 0.40; 95%CI: 0.17-0.95) PA reduced the risk of incident depression compared to none. Being physically active during pandemic, regardless of the amount of PA practiced, reduced the incidence of depression in adults in southern Brazil.

How do different interventions impact stair climbing? A systematic review and meta-analysis.

OBJECTIVES: This study aimed to analyze the effect of interventions to increase stair use. STUDY DESIGN: Systematic review and meta-analysis. METHODS: An online search was conducted in January 2021 in five databases (Web of Science, SPORTDiscus, MedLine/PubMed, PsycINFO, and CINAHL). Experimental studies (randomized and non-randomized) conducted in adults, which provided stair use measures with pre- and post-intervention periods were included. A random-effect meta-analysis, as well as subgroup analyses were conducted to evaluate the quantitative effect of interventions on stair use. RESULTS: Overall, 34 studies were included in qualitative analyses, and 15 in the meta-analysis. Most of the studies were conducted in Europe and private settings (e.g., office buildings). Overall, interventions increased stair use in adults (odds ratio (OR) 1.48; 95% confidence intervals (CI) 1.38-1.58; I2 = 99.6%). Subgroup analyses showed that interventions increased stair use regardless of the continent and observer type (manual or electronic). However, different settings (shopping malls and office buildings), as well as studies (time of intervention) and intervention characteristics (sign size and location, message characters) were associated with increased stair use. CONCLUSIONS: Different interventions can increase stair use in several continents and settings. Sign and message characteristics should be considered when designing interventions or policies to promote physical activity by increasing stair use.

Physical activity trajectory in the first 10 months of the COVID-19 pandemic in Southern Brazil: a follow-up study.

BACKGROUND: A continuous tracking of the PA level during the COVID-19 pandemic is important to understand how people's behaviour has varied along time. The aim of this study was to evaluate the physical activity (PA) trajectory over the first 10 months of the COVID-19 pandemic in the south of Brazil. METHODS: Data from three timepoints of the PAMPA Cohort were used, as follows: (1) pre-COVID-19 (retrospective); (2) Jun/Jul 2020; (3) Dec 2020/Jan 2021. Self-reported PA practice, frequency, duration, as well as place where activities were performed (at or out of home) were assessed. RESULTS: A reduction in any (from 68.7 to 47.7%), sufficient (from 41.5 to 22.1%) and out of home PA (from 59.4 to 30.1%) was observed from the first (pre-COVID-19) to the second (Jun/Jul 2020) timepoint, followed by an increase in the third timepoint (Dec 2020/Jan 2021) (60.1%, 37.9%, and 54.3% for any, sufficient, and out of home PA, respectively). The PA trajectory was similar, regardless of sex, educational level or income. Only any (p = 0.0007) and sufficient (p = 0.0012) PA showed significant interaction with time by sex. Female participants were less likely to engage in any (OR 0.45 95% CI 0.26; 0.77) and sufficient PA (OR 0.40 95% CI 0.24; 0.66). CONCLUSION: During the first 10 months of COVID-19 pandemic there was a marked fluctuation on PA pattern in adults from southern Brazil. An ongoing tracking of PA behaviour during COVID-19 pandemic is important to understand how this behaviour varies. Public policies should focus on increasing PA in a higher standard than pre-COVID levels.

Determinants of increased frequency of depressive and anxiety symptoms in exercise professionals during the COVID-19 pandemic.

BACKGROUND: The coronavirus disease (COVID-19) pandemic has affected workers in different health services including exercise professionals (EP). The urgent need to adapt in-person to online activities might have led to increased frequency of anxiety and depressive symptoms. OBJECTIVE: We aimed to identify the determinants of aggravated depressive and anxiety symptoms in EP in southern Brazil during social distancing from the COVID-19. METHODS: A cross-sectional study was conducted with EP who worked at fitness centers, sports clubs, private schools, or at a public exercise program offered by the municipal council. We used an online-based, self-administered, adapted version of the Hospital Anxiety and Depression scale to compare symptoms of depression and anxiety pre- and during social distancing. RESULTS: Participants (n = 201) had a mean age of 32.7±8.0 years, with more than half being male, white, and having an university degree. We observed that 81%and 71%of respondents reported higher frequency in anxiety and depression symptoms, respectively, during social distancing than in the period before it. Physical education teachers, women, non-white professionals, and those with chronic disease were more likely to worsen anxiety symptoms. Women had higher odds to increased frequency in depressive symptoms. Physical activity and previous experience with internet-based tools for working activities reduced the risk of increased depressive symptoms. CONCLUSIONS: Sex, ethnicity, chronic diseases, educational level, physical activity, and experience with online tools were determinants for increased frequency of depression and anxiety symptoms in EP.

How has COVID-19 social distancing impacted physical activity patterns? Data from the PAMPA cohort, Brazil.

OBJECTIVE: This study aimed to evaluate how social distancing measures affected physical activity (PA) patterns in adults from Rio Grande do Sul, Brazil. METHODS: Participants were recruited from social and local media campaigns, contacts with private and public universities, as well as research personal contacts across the state. PA was assessed before (retrospectively) and during social distancing. Frequency (days per week) and time (minutes per day) were asked to those participants who practiced PA. Two PA variables were built to each time-frame (before and during social distancing): 1) any PA (yes/no question), and 2) sufficient PA (based on the 150 min/week cut-off point). RESULTS: Overall, 2321 participants answered the questionnaire. Any and sufficient PA decreased from before to during social distancing (22.3% and 17.0%, respectively). A linear increase of activity during social distancing was observed in participants who practiced up to 400 min or less of PA per week before social distancing. Regarding associated factors, female, overweight/obese and diagnosed chronic disease participants were less likely to practice any or sufficient PA during social distancing when compared to the period before. CONCLUSION: PA practice (both any and sufficient) decreased in Southern Brazil in the first months of social distancing. Women, overweight/obese and chronic diseased participants showed a higher decrease in PA compared to other groups. Finally, those participants who practiced PA before social distancing were more likely to continue practicing during COVID-19 pandemic.

Are leisure-time and work-related activities associated with low back pain during pregnancy?

BACKGROUND: Although working activities are associated with several pregnancy outcomes, there is scarce information regarding the association between working activities and low back pain (LBP) during pregnancy. This study aimed to investigate whether leisure-time and work-related physical activities during pregnancy are associated with LBP. METHODS: Data from the 2015 Pelotas Birth Cohort study were used. Demographic, socioeconomic, gestational, leisure-time (prior to and during pregnancy) and work-related (days of work, hours of work, standing and heavy lifting) physical activity data were collected at birth. LPB was assessed in the 12-month follow-up period. RESULTS: Leisure-time physical activity either prior to and during pregnancy was not associated with LBP. Working during pregnancy, days of work and standing position at work were not associated with self-reported LBP during pregnancy. However, working more than 8 h per day and always lifting heavy objects at work increased the odds ratio for LBP (OR 1.30 95%CI: 1.04; 1.63; and OR: 1.39 95%CI 1.08; 1.81, respectively). In addition, women who had lifted heavy objects often/always, reported an increase in pain intensity. CONCLUSION: Working during pregnancy and days worked per week were not related to experiencing LBP. However, women who worked more than 8 h per day, as well as women who lifted heavy objects at work on a regular basis, were more likely to experience pregnancy-related LBP.

Two-minute exercise testing is sufficient to estimate maximal cardiorespiratory fitness in people with epilepsy.

We aimed to examine the agreement between submaximal cardiopulmonary exercise testing (CPET) measures and peak oxygen consumption (VO2peak) in adults with epilepsy. Data from a randomized controlled trial with adults with epilepsy (N = 21) were analyzed. VO2peak was assessed using indirect calorimetry during a treadmill graded maximal CPET. Oxygen uptake efficiency slope (OUES) was calculated from the relationship between oxygen uptake and minute ventilation during the entire test (OUESpeak) and the first 2 (OUES2min), 3 (OUES3min), and 4 (OUES4min) minutes of the CPET. The strength of the association between measures was tested by Pearson correlation. Linear regression models were used to predict VO2peak based on OUES from the different testing durations. Agreement between measured and predicted maximal values was tested using intraclass correlation coefficient (ICC) and Bland-Altman plots. OUES2min, OUES3min, and OUES4min were highly associated with absolute (r = 0.84, r = 0.76, r = 0.75, respectively) and relative (r = 0.84, r = 0.78, r = 0.78, respectively) VO2peak. Agreement (ICC = 0.83) between CPET-measured and OUES-predicted VO2peak values was stronger with OUES2min than the other time-based OUES markers. Bland-Altman plot showed satisfactory agreement between predicted and measured CPET measures with the narrowest limits of agreement observed with the OUES2min. No potential bias was identified between these two measurements (p = 0.33). Changes in absolute (r = 0.77) and relative (r = 0.88) VO2peak were highly associated with the change in OUES2min. OUES2min can be used as a surrogate for maximal cardiorespiratory fitness in adults with epilepsy. Studies with larger samples size are encouraged to confirm our findings in a more heterogeneous population.

Association between physical activity and subjective memory decline triggered by the COVID-19 pandemic: Findings from the PAMPA cohort.

Implementation of social distancing reduced the incidence of coronavirus disease (COVID-19) cases. Nevertheless, this strategy has other undesirable effects such as physical inactivity and psychological distress, which are associated with cognitive impairment. We aimed to examine whether physical activity during social distancing restrictions could reduce the risk of subjective memory decline in adults. Participants (n=2321) completed the baseline assessment of PAMPA cohort (Prospective Study About Mental and Physical Health), a ambispective cohort study conducted in southern Brazil. An online-based, self-administered questionnaire assessed physical activity and self-rated memory in two different periods: before and during social distancing. Data collection was executed from June 22nd to July 23rd 2020. Adjusted Poisson regression models were performed and values reported in prevalence ratio (PR) with 95% confidence interval (CI). Participants presented with a mean age of 38.2 (95%CI: 37.5, 38.9) years. Most were women (76.6%), had at least a university degree (66.7%), and were overweight or obese (53.3%). Subjective memory decline was reported by 30.0% (95%CI: 27.7%, 32.4%) of respondents. Most individuals with subjective memory decline reported being physically inactive during the pandemic of COVID-19. Participants were less likely to experience subjective memory decline if they either became (PR: 0.56; 95%CI: 0.36, 0.89) or remained (PR: 0.68; 95%CI: 0.49, 0.93) physically active compared to inactive respondents. Physical activity participation during social distancing reduced the likelihood of subjective memory decline in adults. Physical activity should be highlighted as a potential alternative to reduce the burden of the COVID-19 pandemic on cognitive function and mental health.

Effect of combined physical training on cognitive function in people with epilepsy: Results from a randomized controlled trial.

OBJECTIVE: To examine the effect of 12-week exercise program on cognitive function in people with epilepsy. METHODS: Twenty-one physically inactive subjects were randomized into two groups: the exercise group (EG) or the control group (CG). EG performed 12 weeks of combined physical training. CG was advised to maintain usual daily activities. EG received a structured, individually supervised exercise program with two 60-minute sessions per week. Each session included warmup (5-minutes), aerobic (15-20 minutes at 14-17 on Borg scale), strength (2-3 sets, 10-15 repetitions), and 5-minute active stretches. Sociodemographic characteristics, clinical information, memory (Digit Span Test [DST]), executive function (Trail Making Test [TMT] A and B), Stroop Color and Word Test, a verbal fluency task, global cognitive function (Montreal Cognitive Assessment [MoCA]), anthropometric measurements (weight, height, and hip and waist circumferences), cardiorespiratory fitness (maximal oxygen consumption [VO2 max]), and strength (dynamometer) were measured at baseline and after the 12-week intervention. RESULTS: Exercise decreased time spent on TMT-A from baseline to postintervention (difference = -7.9 seconds, 95% confidence interval [CI] = -14.5 to -1.3, P = .023). EG improved total number of words on the verbal fluency task after intervention (difference = 8.1 words, 95% CI = 3.0 to 13.2, P = .002). EG also improved the score on MoCA at 1.7 (95% CI = 0.1 to 3.3, P = .043) points. We observed a 22.4% (95% CI = 13.1 to 31.6, P = .021) improvement in executive function in EG. No effect of group, time, or group × time was observed on any other cognitive test. Changes in VO2 max were negatively associated with changes in performance on DST (r = -.445, P = .049) and overall memory score (r = -.544, P = .042). SIGNIFICANCE: This randomized controlled trial provided the first evidence that combined physical training improves executive function in adults with epilepsy, showing main improvements in attention and language tasks. Physical exercise should be encouraged for people with epilepsy to reduce the burden on cognitive function associated with this disease.

Saccharomyces cerevisiae var. boulardii fungemia following probiotic treatment.

Probiotics are commonly prescribed as an adjuvant in the treatment of antibiotic-associated diarrhea caused by Clostridium difficile. We report the case of an immunocompromised 73-year-old patient on chemotherapy who developed Saccharomyces cerevisiae var. boulardii fungemia in a central venous catheter during treatment of antibiotic-associated pseudomembranous colitis with the probiotic Saccharomyces cerevisiae var. boulardii. Fungemia was resolved after interruption of probiotic administration without the need to replace the central venous line.

Identification and characterization of a rich population of CD34+ mesenchymal stem/stromal cells in human parotid, sublingual and submandibular glands.

Mesenchymal stem/stromal cells (MSCs) play crucial roles in maintaining tissue homeostasis during physiological turnovers and injuries. Very little is known about the phenotype, distribution and molecular nature of MSCs in freshly isolated human salivary glands (SGs) as most reports have focused on the analysis of cultured MSCs. Our results demonstrate that the cell adhesion molecule CD34 was widely expressed by the MSCs of human major SGs, namely parotid (PAG), sublingual (SLG) and submandibular (SMG) glands. Further, gene expression analysis of CD34+ cells derived from fetal SMGs showed significant upregulation of genes involved in cellular adhesion, proliferation, branching, extracellular matrix remodeling and organ development. Moreover, CD34+ SMG cells exhibited elevated expression of genes encoding extracellular matrix, basement membrane proteins, and members of ERK, FGF and PDGF signaling pathways, which play key roles in glandular development, branching and homeostasis. In vitro CD34+ cell derived SG-MSCs revealed multilineage differentiation potential. Intraglandular transplantation of cultured MSCs in immunodeficient mice led to their engraftment in the injected and uninjected contralateral and ipsilateral glands. Engrafted cells could be localized to the stroma surrounding acini and ducts. In summary, our data show that CD34+ derived SG-MSCs could be a promising cell source for adoptive cell-based SG therapies, and bioengineering of artificial SGs.

Influence of proton pump inhibitors in the development of spontaneous bacterial peritonitis.

AIM: To investigate whether the use of proton pump inhibitors (PPIs) increases the incidence of spontaneous bacterial peritonitis (SBP) in patients with cirrhosis and ascites. METHODS: An historical cohort study was carried out in cirrhotic outpatients with ascites followed in a specialized clinic at a tertiary hospital in Southern Brazil. Patient charts were reviewed to collect information on the variables of interest as the use of PPIs. Primary outcome was defined as development of SBP during the study period. SBP was diagnosed based on ascitic fluid polymorphonuclear cell count ≥ 250 cells/mm³ without evidence of an intra-abdominal, surgically treatable source of infection. RESULTS: Of 738 cirrhotic patients, 582 (58.2% male) were enrolled, with mean age of 53.6 ± 12 years. Hepatitis C virus infection (36.2%) and alcohol abuse (25.6%) were the main etiologies of cirrhosis. The presence of ascites was detected in 299 (51.4%) patients during the development of the study. Nineteen patients with previous diagnosis of SBP undergoing secondary prophylaxis and 22 patients with insufficient PPI data were further excluded. Of 258 patients with ascites, 151 used PPIs, and 34 developed SBP (22.5%). Among 107 non-users of PPIs, 23 developed SBP (21.5%) (HR = 1.44, 95%CI: 0.85-2.47, P = 0.176). The median follow-up time of patients using PPI was 27 mo vs 32 mo for non-users. Univariate analysis of the risk factors associated with the development of SBP revealed a significant association of SPB with the severity of liver disease according to the Child-Turcotte-Pugh (CTP) score. Multivariate analysis confirmed that CTP score was the only independent variable influencing the occurrence of SBP. Survival at 60 mo (Kaplan-Meier analysis) was similar in users and non-users of PPI, independently of the presence of SBP (58.4% vs 62.7% respectively, P = 0.66). For patients with SBP, survival at 60 mo was 55.1%, vs 61.7% in patients without SBP (P = 0.34). CONCLUSION: In conclusion, the rate of SBP was not significantly different in users or non-users of PPIs in this cohort of cirrhotic with ascites.

Conjugation Length Distribution in Poly(p-phenylenevinylene) (PPV) Films.

We studied the absorption line-shape of poly(p-phenylenevinylene) (PPV) films deposited via spin coating and Langmuir-Blodgett techniques with the intent of identifying the conjugation length distribution in these two types of films, a key morphological aspect of conjugated polymer films. We treated the excitons in the polymer as independent oligomer excitons and modeled the absorption spectra of the individual oligomers using simple expressions for the oligomer size dependence of the gap energy, the line-broadening factor, the transition dipole moment and the Huang-Rhys parameter. We validated these expressions by independent measurements on phenyl-based oligomers and Density Functional Theory calculations. Our results show clear evidence that, for both types of PPV films, the conjugation length distribution depends exponentially on the segment size. Our results also set a lower limit, of about ten repeat units, for the maximum exciton length of three different phenyl-based oligomers.

Analysis of longitudinal data of beef cattle raised on pasture from northern Brazil using nonlinear models.

This study was undertaken to aim of estimating the genetic parameters and trends for asymptotic weight (A) and maturity rate (k) of Nellore cattle from northern Brazil. The data set was made available by the Brazilian Association of Zebu Breeders and collected between the years of 1997 and 2007. The Von Bertalanffy, Brody, Gompertz, and logistic nonlinear models were fitted by the Gauss-Newton method to weight-age data of 45,895 animals collected quarterly of the birth to 750 days old. The curve parameters were analyzed using the procedures GLM and CORR. The estimation of (co)variance components and genetic parameters was obtained using the MTDFREML software. The estimated heritability coefficients were 0.21 ± 0.013 and 0.25 ± 0.014 for asymptotic weight and maturity rate, respectively. This indicates that selection for any trait shall results in genetic progress in the herd. The genetic correlation between A and k was negative (-0.57 ± 0.03) and indicated that animals selected for high maturity rate shall result in low asymptotic weight. The Von Bertalanffy function is adequate to establish the mean growth patterns and to predict the adult weight of Nellore cattle. This model is more accurate in predicting the birth weight of these animals and has better overall fit. The prediction of adult weight using nonlinear functions can be accurate when growth curve parameters and their (co)variance components are estimated jointly. The model used in this study can be applied to the prediction of mature weight in herds where a portion of the animals are culled before they reach the adult age.

Musculoskeletal pain in ragpickers in a southern city in Brazil.

BACKGROUND: Ragpickers are informal workers who collect recyclable materials to earn a small wage. Their life and working conditions are extremely precarious. The ergonomic hazards and musculoskeletal pain in a sample of ragpickers in Pelotas, a city in southern Brazil are examined. METHODS: Two comparison groups were available: a matched sample of non-ragpickers from the same poor neighborhoods, and a random sample of the general population of the city. The cross-sectional study gathered data by interview on 990 individuals in 2004. Musculoskeletal pain was assessed using the Standardized Nordic Questionnaire. RESULTS: Ragpickers reported higher prevalences for most awkward postures and ergonomic exposures compared to neighbors with other demanding manual jobs. The prevalence within the last 12 months of low back pain (LBP), lower extremity pain (LEP), and upper extremity pain (UEP) among ragpickers were 49.2%, 45.1%, and 34.9%, respectively; levels similar to those reported by neighborhood controls. Both ragpickers and non-ragpickers reported considerably higher ergonomic exposures, and more prevalent LBP, than the general population. CONCLUSIONS: Ragpickers experience many occupational hazards and ergonomic stressors. Their overall prevalence of musculoskeletal pain was similar to a comparison group with other physically demanding manual jobs. For LBP, this prevalence was substantially higher (49% vs. 35%) than in the general population.