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The title alkali propanoates poly[(μ5-propanoato)alkali(I)], M+(C2H5COO)−, with alkali/M+ = Na+, K+, Rb+ and Cs+, show close structural similarity, which is manifested by the coordination of the cations by six oxygen atoms in a chessboard motif, forming a bilayer. This bilayer is situated between hydrophobic layers composed of dangling ethyl chains from the carboxylate groups. Stacking of these two-dimensional sandwiches, which are parallel to (001), forms the title structures. Each metal cation is coordinated by six O atoms in the form of a distorted trigonal prism. One pair of these oxygen atoms belongs to a bridging, bidentately coordinating carboxylate anion, while each of the other four oxygen atoms belongs to different carboxylate groups, which are in a bridging monodentate mode. Despite the close similarity, each of the studied alkali propanoates crystallizes in a different space group. The atoms are in general positions, except for the cation in K+(C2H5COO)−, which is situated on a mirror plane. Positional disorder of the methyl groups that are disordered over two positions is present in the Na+ and K+ propanoates, in contrast to the Rb+ and Cs+ propanoates. In the Na+ compound, the occupational parameters of the disordered methyl groups are different compared to the K+ compound where they are equal. This difference results in doubling of the a unit-cell parameter of the Na+ compound with respect to that of the K+ compound, otherwise the structures are homeotypic. In Cs+ propanoate, a disorder of the methyl H atoms is observed.

Caesium propanoate monohydrate, Cs+·C3H5O2−·H2O, is composed of two symmetry-independent Cs+ cations, which are situated on the special position 4e of space group P\overline421m, one symmetry-independent propanoate molecule in a general position and a pair of water molecules also situated on special position 4e. Two pairs of these symmetry-independent cations, four propanoate molecules and two pairs of symmetry-independent water molecules form a repeat unit. These units form columns that are directed along the c axis and possess symmetry mm2. There are four such columns passing through each unit cell. Each column is interconnected to its neighbours by four bifurcated three-centred Ow—H...Op (w = water, p = propanoate) hydrogen bonds of moderate strength. There are also four intramolecular Ow—H...Op hydrogen bonds of moderate strength within each column. One Cs+ cation is coordinated by six oxygen atoms (two water and four carboxylate) in a trigonal–prismatic geometry, while the other Cs+ cation is coordinated by four water and four carboxylate O atoms in a tetragonal–prismatic arrangement.

The title compound, {[Ba7(C3H5O2)14]·0.946C3H6O2·4H2O}n, is represented by a metal–organic framework structure that is held together by Ba—O—Ba bonds, as well as by O—H...O hydrogen bonds of moderate strength. The structure comprises of four independent Ba2+ cations (one of which is situated on a twofold rotation axis), seven independent propionate and two independent water molecules. The bond-valence sums of all the cations indicate a slight overbonding. There is also an occupationally, as well as a positionally disordered propionic acid molecule present in the structure. Its occupation is slightly lower than the full occupation while the disordered molecules occupy two positions related by a rotation about a twofold rotation axis. In addition, the methyl group in the symmetry-independent propionic acid molecule is also disordered, and occupies two positions. Each propionic acid molecule coordinates to just one cation from a pair of symmetry-equivalent Ba2+ sites and is simultaneously bonded by an O—H...Opropionate hydrogen bond. This means that on a microscopic scale, the coordination number of the corresponding Ba2+ site is either 9 or 10. The methyl as well as hydroxy hydrogen atoms of the disordered propionic acid molecule were not determined.

Few data have been published on occupational disorders among sports instructors, especially regarding those who are expected to continuously practice while teaching. As the number of sports instructors increases, new specific information about their possible injuries, daily workload, and fitness levels is needed. The aim of this study was to assess occupational disorders, cardiorespiratory fitness, and daily workload of fitness (FI) and swimming instructors (SI). An online survey addressing occupational disorders was conducted among 435 instructors (256 FI and 179 SI). In one subgroup (57 FI and 42 SI), cardiorespiratory fitness levels were evaluated using maximal oxygen consumption (V∙O2max) as an indicator. Daily workload was assessed by monitoring the heart rate and perception of exertion (using the Borg scale). Of the two groups, FI exhibited a higher 2-year prevalence of musculoskeletal injuries and SI experienced more upper respiratory tract infections. V∙O2max ranged from 47.0 to 51.9 ml·kg−1·min−1 and was similar for both FI and SI. Regarding the daily workload, female SI had significantly higher mean heart rate and mean heart rate to maximal heart rate ratio compared to female FI, but no significant differences between male FI and SI were found. No significant differences were observed between the perceived exertion of FI and SI. Preventive strategies for the reduction of occupational disorders in FI and SI are needed.

The title alkali propano­ates poly[(μ5-propano­ato)alkali(I)], M+(C2H5COO)−, with alkali/M+ = Na+, K+, Rb+ and Cs+, show close structural similarity, which is manifested by the coordination of the cations by six oxygen atoms in a chessboard motif, forming a bilayer. This bilayer is situated between hydro­phobic layers composed of dangling ethyl chains from the carboxyl­ate groups. Stacking of these two-dimensional sandwiches, which are parallel to (001), forms the title structures. Each metal cation is coordinated by six O atoms in the form of a distorted trigonal prism. One pair of these oxygen atoms belongs to a bridging, bidentately coordinating carboxyl­ate anion, while each of the other four oxygen atoms belongs to different carboxyl­ate groups, which are in a bridging monodentate mode. Despite the close similarity, each of the studied alkali propano­ates crystallizes in a different space group. The atoms are in general positions, except for the cation in K+(C2H5COO)−, which is situated on a mirror plane. Positional disorder of the methyl groups that are disordered over two positions is present in the Na+ and K+ propano­ates, in contrast to the Rb+ and Cs+ propano­ates. In the Na+ compound, the occupational parameters of the disordered methyl groups are different compared to the K+ compound where they are equal. This difference results in doubling of the a unit-cell parameter of the Na+ compound with respect to that of the K+ compound, otherwise the structures are homeotypic. In Cs+ propano­ate, a disorder of the methyl H atoms is observed. [ABSTRACT FROM AUTHOR]

The title compound, {[Ba7(C3H5O2)14]·0.946C3H6O2·4H2O}n, is represented by a metal-organic framework structure that is held together by Ba-O-Ba bonds, as well as by O-H...O hydrogen bonds of moderate strength. The structure comprises of four independent Ba2+ cations (one of which is situated on a twofold rotation axis), seven independent propionate and two independent water mol­ecules. The bond-valence sums of all the cations indicate a slight overbonding. There is also an occupationally, as well as a positionally disordered propionic acid mol­ecule present in the structure. Its occupation is slightly lower than the full occupation while the disordered mol­ecules occupy two positions related by a rotation about a twofold rotation axis. In addition, the methyl group in the symmetry-independent propionic acid mol­ecule is also disordered, and occupies two positions. Each propionic acid mol­ecule coordinates to just one cation from a pair of symmetry-equivalent Ba2+ sites and is simultaneously bonded by an O-H...Opropionate hydrogen bond. This means that on a microscopic scale, the coordination number of the corresponding Ba2+ site is either 9 or 10. The methyl as well as hy­droxy hydrogen atoms of the disordered propionic acid mol­ecule were not determined. [ABSTRACT FROM AUTHOR]

OBJECTIVES: To assess the prevalence and levels of burnout syndrome among medical students at the Universidade Federal de Sergipe-Brazil and to identify associated factors. METHODS: A cross-sectional study was performed with randomly selected students in 2009. The Maslach Burnout Inventory/Student Survey (MBI-SS) and a structured questionnaire on socio-demographic characteristics, the educational process, and individual aspects were used. Statistical evaluation of multiple variables was performed through backward stepwise logistic regression analysis. RESULTS: The prevalence of burnout was 10.3% (n = 369). The prevalence was higher among those who did not have confidence in their clinical skills (Odds Ratio-OR = 6.47), those who felt uncomfortable with course activities (OR = 5.76), and those who did not see the coursework as a source of pleasure (OR = 4.68). CONCLUSION: There was a significant prevalence of burnout among the medical students studied. Three variables, in particular, were associated with burnout and were directly related to the medical education process. Preventive and intervention measures must be adopted, and longitudinal studies should be conducted.

Two-dimensional diffuse X-ray scattering from an organic salt [ N-(3-(2,6-dimethylanilino)-1-methylbut-2-enylidene)-2,6-dimethylanilinium chloride, C21H27N2+Cl−] was interpreted with the help of an analytical model of diffuse scattering. An analysis of the relationship between symmetry and diffuse scattering for the studied system has been undertaken. The symmetry of the system explains the extinction pattern, taking the form of curves, on the diffuse scattering planes. We have also tested the relationship between the average structure model and scattering intensities. Two models, differing in their representation of overlapping atoms, were used. In the case of diffuse scattering the difference between resulting intensities is immense, while for the Bragg intensities it is much smaller. This sensitivity of diffuse scattering could potentially be used to improve the description of the average structure. [ABSTRACT FROM AUTHOR]

The thermal conductivity of CBr n Cl 4 - n ,(n = 0,1,2) and 2-adamantanone (C 10 H 14 O) crystals which exhibit substitutional disorder has been measured for temperatures between 2 K and 150 K. Such temperatures comprise signatures of dynamical processes involving the site occupancy of the chlorine and bromine atoms for CBr n Cl 4 - n ,(n = 0,1,2) and the oxygen atom for (C 10 H 14 O), as it has been revealed by both, calorimetry and spectroscopic techniques. The data analysis is carried out in terms of several phonon scattering channels contributing to a resistive relaxation rate which can be represented by two contributions due to propagating phonons whose mean-free path exceeds half the phonon wavelength as well as a term attributed to localized short wavelength modes. The implications of the present findings for studies pertaining to glassy dynamics are briefly discussed. [ABSTRACT FROM AUTHOR]