1,338 research outputs found
Smoking, haptoglobin and fertility in humans
A prospective study on two samples of consecutive puerperae (total n° 667) from two populations has been carried out in order to investigate the possible effect of smoking habit on relationship between fertility and haptoglobin phenotype
The genetics of feto-placental development: A study of acid phosphatase locus 1 and adenosine deaminase polymorphisms in a consecutive series of newborn infants
<p>Abstract</p> <p>Background</p> <p>Acid phosphatase locus 1 and adenosine deaminase locus 1 polymorphisms show cooperative effects on glucose metabolism and immunological functions. The recent observation of cooperation between the two systems on susceptibility to repeated spontaneous miscarriage prompted us to search for possible interactional effects between these genes and the correlation between birth weight and placental weight. Deviation from a balanced development of the feto-placental unit has been found to be associated with perinatal morbidity and mortality and with cardiovascular diseases in adulthood.</p> <p>Methods</p> <p>We examined 400 consecutive newborns from the Caucasian population of Rome. Birth weight, placental weight, and gestational length were registered. Acid phosphatase locus 1 and adenosine deaminase locus 1 phenotypes were determined by starch gel electrophoresis and correlation analysis was performed by SPSS programs. Informed verbal consent to participate in the study was obtained from the mothers.</p> <p>Results</p> <p>Highly significant differences in birth weight-placental weight correlations were observed among acid phosphatase locus 1 phenotypes (p = 0.005). The correlation between birth weight and placental weight was markedly elevated in subjects carrying acid phosphatase locus 1 phenotypes with medium-low F isoform concentration (A, CA and CB phenotypes) compared to those carrying acid phosphatase locus 1 phenotypes with medium-high F isoform concentration (BA and B phenotypes) (p = 0.002). Environmental and developmental variables were found to exert a significant effect on birth weight-placental weight correlation in subjects with medium-high F isoform concentrations, but only a marginal effect was observed in those with medium-low F isoform concentrations. The correlation between birth weight and placental weight is higher among carriers of the adenosine deaminase locus 1 allele*2, which is associated with low activity, than in homozygous adenosine deaminase locus 1 phenotype 1 carriers (p = 0.04). The two systems show a cooperative effect on the correlation between birth weight and placental weight: the highest value is observed in newborns carrying adenosine deaminase locus 1 allele*2 and acid phosphatase locus 1 phenotypes with medium-low F isoform concentration (p = 0.005).</p> <p>Conclusion</p> <p>These data suggest that zygotes with low adenosine deaminase locus 1 activity and low F activity may experience the most favourable intrauterine conditions for a balanced development of the feto-placental unit.</p
Relationships among genome size, environmental conditions and geographical distribution in natural populations of NW Patagonian species of Berberis L. (Berberidaceae)
Variation in genome size of 24 populations belonging to 11 NW Patagonian species of Berberis was analysed as a function of the environment and geographical location. The variation showed three levels of discontinuity, two of which corresponded to diploid species (2n = 28) while the third corresponded to polyploid species (2n = 56). Diploids with DNA content ranging from 1.463 pg to 1.857 pg included Berberis cabrerae, B. chillanensis, B. montana, B. serrato-dentata and B. bidentata. Diploids with DNA content ranging from 2.875 pg to 3.806 pg included B. linearifolia, B. darwinii, B. parodii and B. empetrifolia. The genome size of the polyploid species B. buxifolia and B. heterophylla ranged from 5.809 pg to 6.844 pg. Principal component analysis (PCA) was applied to represent the variability of environmental conditions. The eigenvectors of the principal component axes showed that PCl discriminates the populations according to rainfall, types of vegetation and geomorphology; altitude and latitude, on the other hand, contribute to PC2 and PC3, respectively. From these results it is concluded: (1) that diploids with lower DNA content grow in high-elevation sites having greater rainfall but lower water availability; (2) diploids with higher DNA content are associated with half-elevation forests where the vegetative period is longer, the water availability is greater and the temperatures are higher; and (3) the distribution pattern of polyploids is considerably wider than that of diploids, which are geographically and ecologically restricted to forest areas. These results suggest that the C-value plays an important role in the ability of the species to adapt to different growing conditions.Facultad de Ciencias Agrarias y Forestale
Relationships among genome size, environmental conditions and geographical distribution in natural populations of NW Patagonian species of Berberis L. (Berberidaceae)
Variation in genome size of 24 populations belonging to 11 NW Patagonian species of Berberis was analysed as a function of the environment and geographical location. The variation showed three levels of discontinuity, two of which corresponded to diploid species (2n = 28) while the third corresponded to polyploid species (2n = 56). Diploids with DNA content ranging from 1.463 pg to 1.857 pg included Berberis cabrerae, B. chillanensis, B. montana, B. serrato-dentata and B. bidentata. Diploids with DNA content ranging from 2.875 pg to 3.806 pg included B. linearifolia, B. darwinii, B. parodii and B. empetrifolia. The genome size of the polyploid species B. buxifolia and B. heterophylla ranged from 5.809 pg to 6.844 pg. Principal component analysis (PCA) was applied to represent the variability of environmental conditions. The eigenvectors of the principal component axes showed that PCl discriminates the populations according to rainfall, types of vegetation and geomorphology; altitude and latitude, on the other hand, contribute to PC2 and PC3, respectively. From these results it is concluded: (1) that diploids with lower DNA content grow in high-elevation sites having greater rainfall but lower water availability; (2) diploids with higher DNA content are associated with half-elevation forests where the vegetative period is longer, the water availability is greater and the temperatures are higher; and (3) the distribution pattern of polyploids is considerably wider than that of diploids, which are geographically and ecologically restricted to forest areas. These results suggest that the C-value plays an important role in the ability of the species to adapt to different growing conditions.Facultad de Ciencias Agrarias y Forestale
A redshift survey towards the CMB Cold Spot
We have carried out a redshift survey using the VIMOS spectrograph on the VLT
towards the Cosmic Microwave Background cold spot. A possible cause of the cold
spot is the Integrated Sachs-Wolfe effect imprinted by an extremely large void
(hundreds of Mpc in linear dimension) at intermediate or low redshifts. The
redshift distribution of over seven hundred z<1 emission-line galaxies drawn
from an I-band flux limited sample of galaxies in the direction of the cold
spot shows no evidence of a gap on scales of Delta-z> 0.05 as would be expected
if such a void existed at 0.35<z<1. There are troughs in the redshift
distribution on smaller scales (Delta-z ~0.01) indicating that smaller scale
voids may connect regions separated by several degrees towards the cold spot. A
comparison of this distribution with that generated from similarly-sized
subsamples drawn from widely-spaced pointings of the VVDS survey does not
indicate that the redshift distribution towards the cold spot is anomalous or
that these small gaps can be uniquely attributed to real voids.Comment: MNRAS in press, 6 page
Studying the evolution of large-scale structure with the VIMOS-VLT Deep Survey
The VIMOS-VLT Deep Survey (VVDS) currently offers a unique combination of
depth, angular size and number of measured galaxies among surveys of the
distant Universe: ~ 11,000 spectra over 0.5 deg2 to I_{AB}=24 (VVDS-Deep),
35,000 spectra over ~ 7 deg2 to I_{AB}=22.5 (VVDS-Wide). The current ``First
Epoch'' data from VVDS-Deep already allow investigations of galaxy clustering
and its dependence on galaxy properties to be extended to redshifts ~1.2-1.5,
in addition to measuring accurately evolution in the properties of galaxies up
to z~4. This paper concentrates on the main results obtained so far on galaxy
clustering. Overall, L* galaxies at z~ 1.5 show a correlation length r_0=3.6\pm
0.7. As a consequence, the linear galaxy bias at fixed luminosity rises over
the same range from the value b~1 measured locally, to b=1.5 +/- 0.1. The
interplay of galaxy and structure evolution in producing this observation is
discussed in some detail. Galaxy clustering is found to depend on galaxy
luminosity also at z~ 1, but luminous galaxies at this redshift show a
significantly steeper small-scale correlation function than their z=0
counterparts. Finally, red galaxies remain more clustered than blue galaxies
out to similar redshifts, with a nearly constant relative bias among the two
classes, b_{rel}~1.4, despite the rather dramatic evolution of the
color-density relation over the same redshift range.Comment: 14 pages. Extended, combined version of two invited review papers
presented at: 1) XXVIth Astrophysics Moriond Meeting: "From Dark Halos to
Light", March 2006, proc. edited by L.Tresse, S. Maurogordato and J. Tran
Thanh Van (Editions Frontieres); 2) Vulcano Workshop 2006 "Frontier Objects
in Astrophysics and Particle Physics", May 2006, proc. edited by F.
Giovannelli & G. Mannocchi, Italian Physical Society (Editrice Compositori,
Bologna
Geometrical tests of cosmological models. III. The cosmology-evolution diagram at z=1
The rotational velocity of distant galaxies, when interpreted as a size
(luminosity) indicator, may be used as a tool to select high redshift standard
rods (candles) and probe world models and galaxy evolution via the classical
angular diameter-redshift or Hubble diagram tests. We implement the proposed
testing strategy using a sample of 30 rotators spanning the redshift range
0.2<z<1 with high resolution spectra and images obtained by the VIMOS/VLT Deep
Redshift Survey (VVDS) and the Great Observatories Origins Deep Survey (GOODs).
We show that by applying at the same time the angular diameter-redshift and
Hubble diagrams to the same sample of objects (i.e. velocity selected galactic
discs) one can derive a characteristic chart, the cosmology-evolution diagram,
mapping the relation between global cosmological parameters and local
structural parameters of discs such as size and luminosity. This chart allows
to put constraints on cosmological parameters when general prior information
about discs evolution is available. In particular, by assuming that equally
rotating large discs cannot be less luminous at z=1 than at present (M(z=1) <
M(0)), we find that a flat matter dominated cosmology (Omega_m=1) is excluded
at a confidence level of 2sigma and an open cosmology with low mass density
(Omega_m = 0.3) and no dark energy contribution is excluded at a confidence
level greater than 1 sigma. Inversely, by assuming prior knowledge about the
cosmological model, the cosmology-evolution diagram can be used to gain useful
insights about the redshift evolution of the structural parameters of baryonic
discs hosted in dark matter halos of nearly equal masses.Comment: 14 pages and 11 figures. A&A in pres
The VIMOS Public Extragalactic Redshift Survey (VIPERS). Never mind the gaps: comparing techniques to restore homogeneous sky coverage
[Abridged] Non-uniform sampling and gaps in sky coverage are common in galaxy
redshift surveys, but these effects can degrade galaxy counts-in-cells and
density estimates. We carry out a comparison of methods that aim to fill the
gaps to correct for the systematic effects. Our study is motivated by the
analysis of the VIMOS Extragalactic Redshift Survey (VIPERS), a flux-limited
survey (i<22.5) based on one-pass observations with VIMOS, with gaps covering
25% of the surveyed area and a mean sampling rate of 35%. Our findings are
applicable to other surveys with similar observing strategies. We compare 1)
two algorithms based on photometric redshift, that assign redshifts to galaxies
based on the spectroscopic redshifts of the nearest neighbours, 2) two Bayesian
methods, the Wiener filter and the Poisson-Lognormal filter. Using galaxy mock
catalogues we quantify the accuracy of the counts-in-cells measurements on
scales of R=5 and 8 Mpc/h after applying each of these methods. We also study
how they perform to account for spectroscopic redshift error and inhomogeneous
and sparse sampling rate. We find that in VIPERS the errors in counts-in-cells
measurements on R<10 Mpc/h scales are dominated by the sparseness of the
sample. All methods underpredict by 20-35% the counts at high densities. This
systematic bias is of the same order as random errors. No method outperforms
the others. Random and systematic errors decrease for larger cells. We show
that it is possible to separate the lowest and highest densities on scales of 5
Mpc/h at redshifts 0.5<z<1.1, over a large volume such as in VIPERS survey.
This is vital for the characterisation of cosmic variance and rare populations
(e.g, brightest galaxies) in environmental studies at these redshifts.Comment: 17 pages, 13 figures, accepted for publication in A&A (revised
version after minor revision and language editing
The VIMOS Public Extragalactic Redshift Survey (VIPERS). Exploring the dependence of the three-point correlation function on stellar mass and luminosity at 0.5<z<1.1
The three-point correlation function (3PCF) is a powerful probe to
investigate the clustering of matter in the Universe in a complementary way
with respect to lower-order statistics, providing additional information with
respect to the two-point correlation function and allowing us to shed light on
biasing, nonlinear processes, and deviations from Gaussian statistics. In this
paper, we analyse the first data release of the VIMOS Public Extragalactic
Redshift Survey (VIPERS), determining the dependence of the three-point
correlation function on luminosity and stellar mass at . We
exploit the VIPERS Public Data Release 1, consisting of more than 50,000
galaxies with B-band magnitudes in the range and stellar masses in the range
. We measure both the
connected 3PCF and the reduced 3PCF in redshift space, probing different
configurations and scales, in the range [Mpc/h]. We find a
significant dependence of the reduced 3PCF on scales and triangle shapes, with
stronger anisotropy at larger scales ( Mpc/h) and an almost flat trend
at smaller scales, Mpc/h. Massive and luminous galaxies present a
larger connected 3PCF, while the reduced 3PCF is remarkably insensitive to
magnitude and stellar masses in the range we explored. These trends, already
observed at low redshifts, are confirmed for the first time to be still valid
up to , providing support to the hierarchical scenario for which massive
and bright systems are expected to be more clustered. The possibility of using
the measured 3PCF to provide independent constraints on the linear galaxy bias
has also been explored, showing promising results in agreement with other
probes.Comment: 12 pages, 11 figures, 2 tables, accepted for publication in A&
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Diabetes reversal by inhibition of the low-molecular-weight tyrosine phosphatase.
Obesity-associated insulin resistance plays a central role in type 2 diabetes. As such, tyrosine phosphatases that dephosphorylate the insulin receptor (IR) are potential therapeutic targets. The low-molecular-weight protein tyrosine phosphatase (LMPTP) is a proposed IR phosphatase, yet its role in insulin signaling in vivo has not been defined. Here we show that global and liver-specific LMPTP deletion protects mice from high-fat diet-induced diabetes without affecting body weight. To examine the role of the catalytic activity of LMPTP, we developed a small-molecule inhibitor with a novel uncompetitive mechanism, a unique binding site at the opening of the catalytic pocket, and an exquisite selectivity over other phosphatases. This inhibitor is orally bioavailable, and it increases liver IR phosphorylation in vivo and reverses high-fat diet-induced diabetes. Our findings suggest that LMPTP is a key promoter of insulin resistance and that LMPTP inhibitors would be beneficial for treating type 2 diabetes
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