788 research outputs found
Carbohydrate quantity is more closely associated with glycaemic control than weight in pregnant women with type 1 diabetes; insights from the Diabetes and Preâeclampsia Intervention Trial (DAPIT)
Evidence for large superhumps in TX Col and V4742 Sgr
Since the discovery of the largest positive superhump period in TV Col, we
have started a program to search for superhumps in CVs with large orbital
periods. Here, we summarize preliminary results of TX Col and V4742 Sgr. TX Col
is an intermediate polar with a 5.7-h orbital period. V4742 Sgr is a recent
nova with no known periods. CCD unfiltered continuous photometry of these 2
objects was carried out during 56 nights in 2002-3. In TX Col, in addition to
the orbital period of 5.7 h, we found peaks at 7.1 h and 5.0 h. These are
interpreted as positive and negative superhumps correspondingly, although the
effects of the quasi-periodic oscillations at about 2 h were not taken into
consideration. In the light curve of V4742 Sgr 2 long periods are detected --
6.1 and 5.4 h as well as a short-term period at 1.6 h. This result suggests
that V4742 Sgr is an intermediate polar candidate and a permanent superhump
system with a large orbital period (5.4 h) and a superhump period excess of 13
percent. If these results are confirmed, TX Col, V4742 Sgr and TV Col form a
group of intermediate polars with extremely large superhump periods. There
seems to be now growing evidence that superhumps can occur in intermediate
polars with long orbital periods, which is very likely inconsistent with the
theoretical prediction that superhumps can only occur in systems with mass
ratios below 0.33. Alternatively, if the mass ratio in these systems is
nevertheless below the theoretical limit, they should harbour undermassive
secondaries and massive white dwarfs, near the Chandrasekhar limit, which would
make them excellent candidates for progenitors of supernovae type Ia.Comment: 9 pages, 8 figures, 3 sty files, To appear in the proceedings of IAU
JD5, `White Dwarfs: Galactic and Cosmological Probes', eds. Ed Sion, Stephane
Vennes and Harry Shipman, Full abstract in pape
Modelling of Tirapazamine effects on solid tumour morphology
Bioreductive drugs are in clinical practice to exploit the resistance from tumour microenvironments especially in the hypoxic region of tumour. We pre-sented a tumour treatment model to capture the pharmacology of one of the most prominent bioreductive drugs, Tirapazamine (TPZ) which is in clinical trials I and II. We calculated solid tumour mass in our previous work and then integrated that model with TPZ infusion. We calculated TPZ cytotoxicity, concentration, penetra-tion with increasing distance from blood vessel and offered resistance from micro-environments for drug penetration inside the tumour while considering each cell as an individual entity. The impact of these factors on tumour morphology is also showed to see the drug behaviour inside animals/humans tumours. We maintained the heterogeneity factors in presented model as observed in real tumour mass es-pecially in terms of cells proliferation, cell movement, extracellular matrix (ECM) interaction, and the gradients of partial oxygen pressure (pO2) inside tumour cells during the whole growth and treatment activity. The results suggest that TPZ high concentration in combination with chemotherapy should be given to get maximum abnormal cell killing. This model can be a good choice for oncologists and re-searchers to explore more about TPZ action inside solid tumour
Media Effects Reconsidered
Arguments are presented for looking at cognitive outcomes as dependent variables in communication research rather than placing emphasis only on affective realms. This approach also brings attention to the independent-dependent variable emphases found in the communication literature over the last few decades. The social context of media use and the motivations that spring from this contextual embeddedness are also discussed with regard to information utility and the distribution of information availability. Finally a comment is offered on how these perspectives may relate to developments in new media technology.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/66556/2/10.1177_009365027400100205.pd
Ferromagnetic Polarons in La0.5Ca0.5MnO3 and La0.33Ca0.67MnO3
Unrestricted Hartree-Fock calculations on La0.5Ca0.5MnO3 and La0.33Ca0.67MnO3
in the full magnetic unit cell show that the magnetic ground states of these
compounds consist of 'ferromagnetic molecules' or polarons ordered in
herring-bone patterns. Each polaron consists of either three or five Mn ions
separated by O- ions with a magnetic moment opposed to those of the Mn ions.
Ferromagnetic coupling within the polarons is strong while coupling between
them is relatively weak. Magnetic moments on the Mn ions range between 3.8 and
3.9 Bohr magnetons in La0.5Ca0.5MnO3 and moments on the O- ions are -0.7 Bohr
magnetons. Each polaron has a net magnetic moment of 7.0 Bohr magnetons, in
good agreement with recently reported magnetisation measurements from electron
microscopy. The polaronic nature of the electronic structure reported here is
obviously related to the Zener polaron model recently proposed for
Pr0.6Ca0.4MnO3 on the basis of neutron scattering data.Comment: 4 pages 5 figure
Exchange coupling in CaMnO and LaMnO: configuration interaction and the coupling mechanism
The equilibrium structure and exchange constants of CaMnO and LaMnO
have been investigated using total energy unrestricted Hartree-Fock (UHF) and
localised orbital configuration interaction (CI) calculations on the bulk
compounds and MnO and MnO clusters. The
predicted structure and exchange constants for CaMnO are in reasonable
agreement with estimates based on its N\'eel temperature. A series of
calculations on LaMnO in the cubic perovskite structure shows that a
Hamiltonian with independent orbital ordering and exchange terms accounts for
the total energies of cubic LaMnO with various spin and orbital orderings.
Computed exchange constants depend on orbital ordering. UHF calculations tend
to underestimate exchange constants in LaMnO, but have the correct sign
when compared with values obtained by neutron scattering; exchange constants
obtained from CI calculations are in good agreement with neutron scattering
data provided the Madelung potential of the cluster is appropriate. Cluster CI
calculations reveal a strong dependence of exchange constants on Mn d e
orbital populations in both compounds. CI wave functions are analysed in order
to determine which exchange processes are important in exchange coupling in
CaMnO and LaMnO.Comment: 25 pages and 9 postscript figure
Optimising fisheries management in relation to tuna catches in the western central Pacific Ocean: A review of research priorities and opportunities
Some of the most important development goals for the countries and territories of the Western and Central Pacific Ocean (WCPO) involve the sustainable management of their fisheries in light of environmental, economic and social uncertainties. The responses of fish populations to variability in the marine environment have implications for decision making processes associated with resource management. There is still considerable uncertainty in estimating the responses of tuna populations to short-to-medium-term variability and longer-term change in the oceanic environment. A workshop was organised to examine how advances in oceanography, fisheries science and fisheries economics could be applied to the tuna fisheries of the WCPO and in doing so identify research priorities to improve understanding relevant to progressing management. Research priorities identified included: (i) improved parameterisation of end to end ecosystem model components, processes and feedbacks through expanded biological observations and incorporation of higher resolution climate models; (ii) development of seasonal and inter-annual forecasting tools enabling management responses to short-term variability in tuna distributions and abundances; (iii) improved understanding of the population dynamics of and the energy transfer efficiencies between food web components; (iv) assessment of the optimal value of access rights and overall fishery value under multiple scenarios of tuna distribution and abundance and influences on decision making by fisheries managers and fleets and (v) development of management strategy evaluation frameworks for utilisation in the implementing and testing of fishery management procedures and to help prioritise research directions and investment. Issues discussed and research priorities identified during the workshop have synergies with other internationally managed fisheries and therefore are applicable to many other fisheries
Relationships of psychosocial factors to dietary intakes of preadolescent girls from diverse backgrounds
Family and personal factors that might be related to the development of food selection and eating patterns have not been well studied in children. The aim of this study was to examine whether such psychosocial factors differ in girls from four culturally diverse Girl Scout troops and how these factors are associated with dietary intakes. The social measures and dietary assessments were all obtained at baseline on subjects who were participating in a small nutrition education programme. The programme enrolled girls and one parent for each girl from four Girl Scout troops in Detroit, Michigan. The social factors assessed included girlsâ emotionality and use of food to regulate emotions, their general attitudes about health, eating and body image, and self-perceptions of their competence. Dietary intakes also were assessed in both the girls and their parents. There were large differences between troops in ethnicity and parent education level, and there were differences in dietary intakes as well. The psychosocial factors assessed in this study, however, did not differ significantly by troop. When the psychosocial factors were examined for their relationships to dietary factors, there was an indication that families which reported higher self-competence and academic competence in their daughters also had healthier eating patterns in their daughters. This was a small study, but the data suggest that simple comparisons between ethnic groups may not adequately capture the complexity of family and psychosocial factors contributing to good dietary practices.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/73597/1/j.1740-8709.2006.00051.x.pd
Idling Magnetic White Dwarf in the Synchronizing Polar BY Cam. The Noah-2 Project
Results of a multi-color study of the variability of the magnetic cataclysmic
variable BY Cam are presented. The observations were obtained at the Korean
1.8m and Ukrainian 2.6m, 1.2m and 38-cm telescopes in 2003-2005, 56
observational runs cover 189 hours. The variations of the mean brightness in
different colors are correlated with a slope dR/dV=1.29(4), where the number in
brackets denotes the error estimates in the last digits. For individual runs,
this slope is much smaller ranging from 0.98(3) to 1.24(3), with a mean value
of 1.11(1). Near the maximum, the slope becomes smaller for some nights,
indicating more blue spectral energy distribution, whereas the night-to-night
variability has an infrared character. For the simultaneous UBVRI photometry,
the slopes increase with wavelength from dU/dR=0.23(1) to dI/dR=1.18(1). Such
wavelength dependence is opposite to that observed in non-magnetic cataclysmic
variables, in an agreement to the model of cyclotron emission. The principal
component analysis shows two (with a third at the limit of detection)
components of variablitity with different spectral energy distribution, which
possibly correspond to different regions of emission. The scalegram analysis
shows a highest peak corresponding to the 200-min spin variability, its quarter
and to the 30-min and 8-min QPOs. The amplitudes of all these components are
dependent on wavelength and luminosity state. The light curves were fitted by a
statistically optimal trigonometrical polynomial (up to 4-th order) to take
into account a 4-hump structure. The dependences of these parameters on the
phase of the beat period and on mean brightness are discussed. The amplitude of
spin variations increases with an increasing wavelength and with decreasing
brightnessComment: 30pages, 11figures, accepted in Cent.Eur.J.Phy
A new protocol for the propagation of dendritic cells from rat bone marrow using recombinant GM-CSF, and their quantification using the mAb OX-62
Bone marrow (BM)-derived dendritic cells (DC) are the most potent known antigen (Ag) presenting cell in vivo and in vitro. Detailed analysis of their properties and mechanisms of action requires an ability to produce large numbers of DC. Although DC have been isolated from several rat tissues, including BM, the yield is uniformly low. We describe a simple method for the propagation of large numbers of DC from rat BM and document cell yield with the rat DC marker, OX-62. After depletion of plastic-adherent and Fc+ cells by panning on dishes coated with normal serum, residual BM cells were cultured in gelatin coated flasks using murine rGM-CSF supplemented medium. Prior to analysis, non-adherent cells were re-depleted of contaminating Fc+ cells. Propagation of DC was monitored by double staining for FACS analysis (major histocompatibility complex (MHC) class II+ OX-62+, OX-19-). Functional assay, morphological analysis and evaluation of homing patterns of cultured cells revealed typical DC characteristics. MHC class II and OX-62 antigen expression increased with time in culture and correlated with allostimulatory ability. DC yield increased until day 7, when 3.3 à 106 DC were obtained from an initial 3 à 108 unfractionated BM cells. Significant numbers of DC can be generated from rat BM using these simple methods. This should permit analysis and manipulation of rat DC functions in vivo and in vitro. © 1995
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