2,114 research outputs found
Validation of stellar population and kinematical analysis of galaxies
3D spectroscopy produces hundreds of spectra from which maps of the
characteristics of stellar populations (age-metallicity) and internal
kinematics of galaxies can be derived. We carried on simulations to assess the
reliability of inversion methods and to define the requirements for future
observations. We quantify the biases and show that to minimize the errors on
the kinematics, age and metallicity (in a given observing time) the size of the
spatial elements and the spectral dispersion should be chosen to obtain an
instrumental velocity dispersion comparable to the physical dispersion.Comment: 5 pages, 3 figures, extended version of a poster proceeding to appear
in "Science Perspectives for 3D Spectroscopy", eds. M. Kissler-Patig, M. M.
Roth and J. R. Walsh, ESO Astrophysics Symposia. (The two last pages with
figures are not in the conference proceedings.
З листування Л. Биковського з Є. Бачинським
У статті надається листування видатного бібліографа, історика Л. Биковського з визначним українським громадським і церковним діячем Є. Бачинським. листи написані в 1947–1952 рр.В статье представлена переписка выдающегося библиографа, историка Л. Быковского с выдающимся украинским общественным и церковным деятелем Е. Бачинским. Письма написаны в 1947-1952 гг.The article consists of correspondence of the outstanding bibliographer, historian L.Bykovskyi with the outstanding Ukrainian public and church figure Ye. Bachynskyi. Letters are written in 1947–1952
A discovery down under: decoding the draft genome sequence of Pantoea stewartii from Australia's Critically Endangered western ground parrot / kyloring (Pezoporus flaviventris)
Pantoea stewartii, a plant pathogen, is primarily transmitted through contaminated seeds and insect vectors, with the corn flea beetle (Chaetocnema pulicaria) being the primary carrier. P. stewartii is a bacterium belonging to the order Enterobacterales and can lead to crop diseases that have a significant economic impact worldwide. Due to its high potential for spread, P. stewartii is classified as a quarantine organism in numerous countries. Despite its impact on agriculture, the limited genome sequences of P. stewartii hamper understanding of its pathogenicity and host specificity, and the development of effective control strategies. In this study, a P. stewartii strain (C10109_Jinnung) was discovered in the faecal matter of the Critically Endangered western ground parrot/kyloring (Pezoporus flaviventris) in Australia, which to our knowledge is the first reported P. stewartii genome from a bird source. Whole-genome sequencing and phylogenomic analysis of strain C10109_Jinnung, obtained from a captive psittacine, provides new insights into the genetic diversity and potential transmission route for the spread of P. stewartii beyond insects and plants, where P. stewartii is typically studied. Our findings provide new insights into the potential transmission route for spread of P. stewartii and expand the known transmission agents beyond insects and plants. Expanding the catalogue of P. stewartii genomes is fundamental to improving understanding of the pathogenicity, evolution and dissemination, and to develop effective control strategies to reduce the substantial economic losses associated with P. stewartii in various crops and the potential impact of endangered animal species
Spin dynamics of wave packets evolving with the Dirac Hamiltonian in atoms with high Z
The motion of circular WP for one electron in central Coulomb field with high
Z is calculated. The WP is defined in terms of solutions of the Dirac equation
in order to take into account all possible relevant effects in particular the
spin-orbit potential. A time scale is defined within which spin dynamics must
be taken into account mainly in the atoms with high Z. Within this time scale
there exists a mechanism of collapses and revivals of the spin already shown by
the authors for harmonic oscillator potential and called the 'spin-orbit
pendulum'. However this effect has not the exact periodicity of the simpler
model, but the WP's spatial motion is nevertheless quite similar.Comment: 17 pages, 9 figures, LaTeX2e, uses IOP style files (included). Title
changed, one reference adde
Virtual versus Real Nuclear Compton Scattering in the Delta(1232) Region
In this paper we calculate the cross section for Virtual Compton Scattering
off nuclei in the delta resonance region. We also calculate the background for
the process from Coherent Bremsstrahlung in nuclei and explore the regions
where the Virtual Compton Scattering cross section dominates. The study also
shows that it is possible to extract the cross section for Real Compton
Scattering from the Virtual Compton one in a wide range of scattering angles.Comment: latex , 11 pages, ps.gz file, 16 figure
Ghrelin is not Related to Hunger or Calories Consumed at Breakfast in Lean and Obese Women
poster abstractBackground: The mechanisms that result in greater caloric intake in obese individuals
are incompletely understood. Ghrelin administration increases ad lib food intake in
humans. We investigated the relationship of ghrelin to calorie consumption and hunger
at breakfast on two separate occasions in lean and obese women.
Methods: 23 lean (BMI 22.3±0.5 kg/m2, 26.5±1.0 yr) and 25 obese (BMI 36.9±0.7 kg/m2,
27.8±1.1 yr) women participated in a noncontiguous 2 day study. The minimum and
maximum days between visits were 6 and 43 days. Participants were given the same
breakfast on both days (turkey sausage, French toast with margarine/syrup, fruit cup,
coffee, tea, diet soda, or water) with portions adjusted to provide 20% of the daily energy
requirement for weight maintenance. Subjects were instructed to eat until full. Hunger
was evaluated on a Satiety Labeled Intensity Magnitude Scale (SLIM) before and after
the meal. Anchors were “greatest imaginable fullness” at 0 and “greatest imaginable
hunger” at 100. Blood samples were collected over 120 minutes for measurement of
active ghrelin.
Results: Lean subjects consumed an equivalent number of calories on both days
(380.0±14.6 vs 378.2±14.9 kcal), as did the obese (419.4±16.2 vs 428.8±15.4 kcal). On
average for both days, obese consumed significantly more breakfast calories than lean
(424.1±11.1 vs 379.1±10.3 kcal; P<0.01), but the same percentage of calories provided
(85.7±1.8 vs 86.1±1.7 %kcal). Lean subjects rated hunger before breakfast the same on
both days (69.2±1.6 vs 71.7±1.4), as did the obese (69.8±1.6 vs 69.6±1.8), and there
was no difference between the groups. Lean subjects rated hunger after breakfast the
same on both days (27.8±1.9 vs 30.3±2.4), as did the obese (25.0±1.7 vs 24.3±1.8).
The reduction in hunger score following breakfast was significant for both groups
(P<0.0001), with the obese reporting significantly less hunger/more fullness after
breakfast than the lean (P=0.02). Fasting ghrelin was significantly greater in the lean
than obese women (549.9±58.9 vs 231.0±29.1 pg/ml; P<0.0001). Ghrelin was
significantly reduced at 60 min following breakfast in the lean (375.8±49.2 pg/ml;
P=0.028) but not the obese (212.2±26.4 pg/ml). Ghrelin was not related to hunger score
prior to breakfast, and there was no relationship between reduction in ghrelin and hunger
score in the lean or obese.
Conclusion: Caloric intake (as a percentage provided) and hunger scores before
breakfast on two occasions were the same for both lean and obese women. Fasting
ghrelin was significantly different between lean and obese women but did not predict
hunger score or calories consumed. Our findings do not support a role for ghrelin in
driving food intake at breakfast
Average luminosity distance in inhomogeneous universes
The paper studies the correction to the distance modulus induced by
inhomogeneities and averaged over all directions from a given observer. The
inhomogeneities are modeled as mass-compensated voids in random or regular
lattices within Swiss-cheese universes. Void radii below 300 Mpc are
considered, which are supported by current redshift surveys and limited by the
recently observed imprint such voids leave on CMB. The averaging over all
directions, performed by numerical ray tracing, is non-perturbative and
includes the supernovas inside the voids. Voids aligning along a certain
direction produce a cumulative gravitational lensing correction that increases
with their number. Such corrections are destroyed by the averaging over all
directions, even in non-randomized simple cubic void lattices. At low
redshifts, the average correction is not zero but decays with the peculiar
velocities and redshift. Its upper bound is provided by the maximal average
correction which assumes no random cancelations between different voids. It is
described well by a linear perturbation formula and, for the voids considered,
is 20% of the correction corresponding to the maximal peculiar velocity. The
average correction calculated in random and simple cubic void lattices is
severely damped below the predicted maximal one after a single void diameter.
That is traced to cancellations between the corrections from the fronts and
backs of different voids. All that implies that voids cannot imitate the effect
of dark energy unless they have radii and peculiar velocities much larger than
the currently observed. The results obtained allow one to readily predict the
redshift above which the direction-averaged fluctuation in the Hubble diagram
falls below a required precision and suggest a method to extract the background
Hubble constant from low redshift data without the need to correct for peculiar
velocities.Comment: 34 pages, 21 figures, matches the version accepted in JCA
Anti-Mullerian hormone attenuates the effects of FSH on follicle development in the mouse ovary
Although ovarian follicle growth is under the influence of many growth
factors and hormones of which FSH remains one of the most prominent
regulators. Therefore, factors affecting the sensitivity of ovarian
follicles to FSH are also important for follicle growth. The aim of the
present study was to investigate whether anti-Mullerian hormone (AMH) has
an inhibitory effect on follicle growth by decreasing the sensitivity of
ovarian follicles to FSH. Furthermore, the combined action of AMH and FSH
on ovarian follicle development was examined. Three different experiments
were performed. Using an in vitro follicle culture system it was shown
that FSH-stimulated preantral follicle growth is attenuated in the
presence of AMH. This observation was confirmed by an in vivo experiment
showing that in immature AMH-deficient females, more follicles start to
grow under the influence of exogenous FSH than in their wild-type
littermates. In a third experiment, examination of the follicle population
of 4-month-old wild-type, FSH beta-, AMH-, and AMH-/FSH beta-deficient
females revealed that loss of FSH expression has no impact on the number
of primordial and preantral follicles, but the loss of inhibitory action
of AMH on the recruitment of primordial follicles in AMH-deficient mice is
increased in the absence of FSH. In conclusion, these studies show that
AMH inhibits FSH-stimulated follicle growth in the mouse, suggesting that
AMH is one of the factors determining the sensitivity of ovarian follicles
for FSH and that AMH is a dominant regulator of early follicle growth
Compton scattering on the proton, neutron, and deuteron in chiral perturbation theory to O(Q^4)
We study Compton scattering in systems with A=1 and 2 using chiral
perturbation theory up to fourth order. For the proton we fit the two
undetermined parameters in the O(Q^4) p amplitude of McGovern to
experimental data in the region MeV, obtaining a
chi^2/d.o.f. of 133/113. This yields a model-independent extraction of proton
polarizabilities based solely on low-energy data: alpha_p=12.1 +/- 1.1 (stat.)
+/- 0.5 (theory) and beta_p=3.4 +/- 1.1 (stat.) +/- 0.1 (theory), both in units
of 10^{-4} fm^3. We also compute Compton scattering on deuterium to O(Q^4). The
d amplitude is a sum of one- and two-nucleon mechanisms, and contains
two undetermined parameters, which are related to the isoscalar nucleon
polarizabilities. We fit data points from three recent d scattering
experiments with a chi^2/d.o.f.=26.6/20, and find alpha_N=13.0 +/- 1.9 (stat.)
+3.9/-1.5 (theory) and a beta_N that is consistent with zero within sizeable
error bars.Comment: 57 pages, 16 figures. Substantial changes. Correction of errors in
deuteron calculation results in different values for isoscalar
polarizabilities. Results for the proton are unaffected. Text modified to
reflect this change, and also to clarify various point
‘What are you going to do, confiscate their passports?’ Professional perspectives on cross-border reproductive travel
Objective: This article reports findings from a UK-based study which explored the phenomenon of overseas travel for fertility treatment. The first phase of this project aimed to explore how infertility clinicians and others professionally involved in fertility treatment understand the nature and consequences of cross-border reproductive travel. Background: There are indications that, for a variety of reasons, people from the UK are increasingly travelling across national borders to access assisted reproductive technologies. While research with patients is growing, little is known about how ‘fertility tourism’ is perceived by health professionals and others with a close association with infertility patients. Methods: Using an interpretivist approach, this exploratory research included focussed discussions with 20 people professionally knowledgeable about patients who had either been abroad or were considering having treatment outside the UK. Semi-structured interviews were recorded, transcribed verbatim and subjected to a thematic analysis. Results: Three conceptual categories are developed from the data: ‘the autonomous patient’; ‘cross-border travel as risk’, and ‘professional responsibilities in harm minimisation’. Professionals construct nuanced, complex and sometimes contradictory narratives of the ‘fertility traveller’, as vulnerable and knowledgeable; as engaged in risky behaviour and in its active minimisation. Conclusions: There is little support for the suggestion that states should seek to prevent cross-border treatment. Rather, an argument is made for less direct strategies to safeguard patient interests. Further research is required to assess the impact of professional views and actions on patient choices and patient experiences of treatment, before, during and after travelling abroad
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