520 research outputs found
Incommensurate chirality density wave transition in a hybrid molecular framework
Using single-crystal X-ray diffraction we characterise the 235\,K
incommensurate phase transition in the hybrid molecular framework
tetraethylammonium silver(I) dicyanoargentate, [NEt]Ag(CN). We
demonstrate the transition to involve spontaneous resolution of chiral
[NEt] conformations, giving rise to a state in which molecular
chirality is incommensurately modulated throughout the crystal lattice. We
refer to this state as an incommensurate chirality density wave (XDW) phase,
which represents a fundamentally new type of chiral symmetry breaking in the
solid state. Drawing on parallels to the incommensurate ferroelectric
transition of NaNO we suggest the XDW state arises through coupling between
acoustic (shear) and molecular rotoinversion modes. Such coupling is
symmetry-forbidden at the Brillouin zone centre but symmetry-allowed for small
but finite modulation vectors . The importance of
long-wavelength chirality modulations in the physics of this hybrid framework
may have implications for the generation of mesoscale chiral textures, as
required for advanced photonic materials.Comment: 5 pages, 3 figure
Charge-ice dynamics in the negative thermal expansion material Cd(CN)
We use variable-temperature (150--300\,K) single-crystal X-ray diffraction to
re-examine the interplay between structure and dynamics in the ambient phase of
the isotropic negative thermal expansion (NTE) material Cd(CN). We find
strong experimental evidence for the existence of low-energy vibrational modes
that involve off-centering of Cd ions. These modes have the effect of
increasing network packing density---suggesting a mechanism for NTE that is
different to the generally-accepted picture of correlated Cd(C/N) rotation
modes. Strong local correlations in the displacement directions of neighbouring
cadmium centres are evident in the existence of highly-structured diffuse
scattering in the experimental X-ray diffraction patterns. Monte Carlo
simulations suggest these patterns might be interpreted in terms of a basic set
of `ice-rules' that establish a mapping between the dynamics of Cd(CN) and
proton ordering in cubic ice VII.Comment: 5 pages, 5 figures, submitted to PR
Pengaruh Gaya Kepemimpinan Terhadap Kinerja Karyawan (Studi Pada Karyawan Tetap Service Center Panasonic Surabaya)
Research entitled “The Influence Leadership Style on Employee Performance” conducted on permanent employees at Service Center Panasonic Surabaya aims to explain at influence of leadership style partially on employee performance. The research method used is explanatory research, collecting data using questionnaires distributed to all permanent employees of Panasonic Service Center Surabaya which amounted to 48 respondents. Data analysis used in this research is descriptive analysis and multiple linear regression using SPSS 18 for windows. The results showed Democratic Leadership Style had the most significant effect on employee performance compared Authoritarian Leadership Style and Laissez-Faire Leadership Style
Study of Mill Island ice core (East Antarctica): A sensitive site for high resolution ocean climate signals?
第2回極域科学シンポジウム 氷床コアセッション 11月16日(水) 国立極地研究所 2階大会議
Identifying inequities in maternal and child health through risk stratification to inform health systems strengthening in Northern Togo
ObjectiveIn Togo, substantial progress in maternal and child health is needed to reach global development goals. To better inform clinic and community-based health services, this study identifies factors associated with maternal and child health care utilization in the Kara region of Northern Togo.
Methods We conducted a population-representative household survey of four health clinic catchment areas of 1,075 women of reproductive age in 2015. Multivariable logistic regression was used to model individual and structural factors associated with utilization of four maternal and child health services. Key outcomes were: facility-based delivery, maternal postnatal health check by a health professional within the first six weeks of birth, childhood vaccination, and receipt of malaria medication for febrile children under age five within 72 hours of symptom onset.
Results 83 percent of women who gave birth in the last 2 years delivered at a health facility. In adjusted models, the strongest predictor of facility delivery in the rural catchment areas was proximity to a health center, with women living under three kilometers having 3.7 (95% CI 1.7, 7.9) times the odds of a facility birth. Only 11 percent of women received a health check by a health provider at any time in the postnatal period. Postnatal health checks were less likely for women in the poorest households and for women who resided in rural areas. Children of polygamous mothers had half the odds of receiving malaria medication for fever within 72 hours of symptom onset, while children with increased household wealth status had increased odds of childhood vaccination and receiving treatment for malaria.
Conclusion Our analysis highlights the importance of risk stratification analysis to inform the delivery and scope of maternal and child health programs needed to reach those with the least access to care
Climate, landscape, habitat, and woodland management associations with hazel dormouse Muscardinus avellanarius population status
Although strictly protected, populations of the hazel dormouse Muscardinus avellanarius in the UK declined by 72% from 1993 to 2014. Using National Dormouse Monitoring Programme data from 300 sites throughout England and Wales, we investigated variation in hazel dormouse population status (expressed as Indices of Abundance, Breeding, and population Trend) in relation to climate, landscape, habitat, and woodland management. Dormice were more abundant and produced more litters on sites with warmer, sunnier springs, summers, and autumns. Dormouse abundance was also higher on sites with consistently cold local climate in winter. Habitat connectivity, woodland species composition, and active site management were all correlated with greater dormouse abundance and breeding. Abundances were also higher on sites with successional habitats, whereas the abundance of early successional bramble Rubus fruticosus habitat, woodland area, and landscape connectivity were important for population stability. Diversity in the structure of woodlands in Europe has decreased over the last 100 years, and the habitats we found to be associated with more favourable dormouse status have also been in decline. The conservation status of the hazel dormouse, and that of woodland birds and butterflies, may benefit from reinstatement or increased frequency of management practices, such as coppicing and glade management, that maintain successional and diverse habitats within woodland
Spatial Localization and Quantitation of Androgens in Mouse Testis by Mass Spectrometry Imaging
Androgens
are essential for male development and reproductive function.
They are transported to their site of action as blood-borne endocrine
hormones but can also be produced within tissues to act in intracrine
and paracrine fashions. Because of this, circulating concentrations
may not accurately reflect the androgenic influence within specific
tissue microenvironments. Mass spectrometry imaging permits regional
analysis of small molecular species directly from tissue surfaces.
However, due to poor ionization and localized ion suppression, steroid
hormones are difficult to detect. Here, derivatization with Girard
T reagent was used to charge-tag testosterone and 5α-dihydrotestosterone
allowing direct detection of these steroids in mouse testes, in both
basal and maximally stimulated states, and in rat prostate. Limits
of detection were ∼0.1 pg for testosterone. Exemplary detection
of endogenous steroids was achieved by matrix-assisted laser desorption
ionization and either Fourier transform ion cyclotron resonance detection
(at 150 μm spatial resolution) or quadrupole-time-of-flight
detection (at 50 μm spatial resolution). Structural confirmation
was achieved by collision induced fragmentation following liquid extraction
surface analysis and electrospray ionization. This application broadens
the scope for derivatization strategies on tissue surfaces to elucidate
local endocrine signaling in health and disease
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