3,955 research outputs found
A SINFONI view of flies in the Spiderweb: a galaxy cluster in the making
The environment of the high-z radio galaxy PKS 1138-262 at z~2.2 is a prime
example of a forming galaxy cluster. We use deep SINFONI data to perform a
detailed study of the kinematics of the galaxies within 60 kpc of the radio
core and we link this to the kinematics of the protocluster on the megaparsec
scale. Identification of optical emission lines shows that 11 galaxies are at
the redshift of the protocluster. The density of line emitters is more than an
order of magnitude higher in the core of the protocluster than the larger scale
environment. This implies a matter overdensity in the core of delta_m~70 which
is similar to the outskirts of local galaxy clusters. The velocity distribution
of the confirmed satellite galaxies shows a broad, double-peaked velocity
structure with sigma=1360+/-206 km/s. A similar broad, double-peaked
distribution was found in a previous study targeting the large scale
protocluster structure, indicating that a common process is acting on both
small and large scales. Including all spectroscopically confirmed protocluster
galaxies, a velocity dispersion of 1013+/-87 km/s is found. We show that the
protocluster has likely decoupled from the Hubble flow and is a dynamically
evolved structure. Comparison to the Millenium simulation indicates that the
protocluster velocity distribution is consistent with that of the most massive
haloes at z~2, but we rule out that the protocluster is a fully virialized
structure based on dynamical arguments and its X-ray luminosity. Comparison to
merging haloes in the Millennium simulation shows that the structure as
observed in and around the Spiderweb galaxy is best interpreted as being the
result of a merger between two massive haloes. We propose that this merger can
result in an increase in star formation and AGN activity in the protocluster
core and is possibly an important stage in the evolution of massive cD
galaxies.Comment: 12 pages, 7 figures. Accepted for publication in MNRA
Safety and efficacy of natalizumab in children with multiple sclerosis.
OBJECTIVE: To describe the effect of natalizumab in the treatment of subjects
with active multiple sclerosis (MS) treated before the age of 18 years.
METHODS: Nineteen pediatric subjects with MS (mean age 14.6 +/- 2.2 years, mean
number of attacks 5.2 +/- 1.9 during the pretreatment phase of 27.7 +/- 19.7
months, median pretreatment Expanded Disability Status Scale score [EDSS] 2.5,
range 1.0-5.0) were treated with natalizumab at the dose of 300 mg every 28 days.
After treatment initiation, patients were reassessed clinically every month;
brain MRI was performed at baseline and every 6 months.
RESULTS: Patients received a median number of 15 infusions (range 6-26). A
transient reversible worsening of preexisting symptoms occurred in 1 subject
during and following the first infusion. All the patients remained relapse-free
during the whole follow-up. The median EDSS decreased from 2.5 to 2.0 at the last
visit (p < 0.001). EDSS remained stable in 5 cases, decreased by at least 0.5
point in 6 cases, and decreased by at least 1 point in 8 cases. At baseline, the
mean number of gadolinium-enhancing lesions was 4.1 (range 1-20). During the
follow-up, no gadolinium-enhancing lesions were detected (p = 0.008); 3 patients
developed new T2-visible lesions at month 6 scan but the overall number of T2
lesions remained stable during the subsequent follow-up. Transient and mild side
effects occurred in 8 patients.
CONCLUSIONS: Natalizumab was well-tolerated in all subjects. A strong suppression
of disease activity was observed in all subjects during the follow-up.
Classification of evidence: This study provides Class IV evidence that
natalizumab, 300 mg IV once every 28 days, decreased EDSS scores in pediatric
patients with MS over a mean treatment period of 15.2 months
Momento Económico (50)
En este número:
Historia y Modernización.
El Programa de Ciencia y Modernización Tecnológica,
1990-1994.
Algunos comentarios generales al Programa de Ciencia y Modernización Tecnológica 1990-1994.
Los objetivos del Programa Nacional de Población 1989-1994.
La movilidad urbana en la Ciudad de México.
Importación de leche en polvo en México: la utopía de la autosuficiencia lechera.
América Latina: aspectos de la década perdida.
Notas sobre la modernización agroindustrial.
¿Qué es el Estado ex-socialista ?.
La investigación nacional y el Congreso Universitario.
Temas de hoy
Effective Rheology of Bubbles Moving in a Capillary Tube
We calculate the average volumetric flux versus pressure drop of bubbles
moving in a single capillary tube with varying diameter, finding a square-root
relation from mapping the flow equations onto that of a driven overdamped
pendulum. The calculation is based on a derivation of the equation of motion of
a bubble train from considering the capillary forces and the entropy production
associated with the viscous flow. We also calculate the configurational
probability of the positions of the bubbles.Comment: 4 pages, 1 figur
Gd(III) complexes intercalated into hydroxy double salts as potential MRI contrast agents
The ion exchange intercalation of two Gd-based magnetic resonance imaging contrast agents into hydroxy double salts (HDSs) is reported. The presence of Gd3+ diethylenetriaminepentaacetate and Gd3+ diethylenetriaminepenta(methylenephosphonate) complexes in the HDS lattice after intercalation was confirmed by microwave plasma-atomic emission spectroscopy. The structural aspects of the HDS-Gd composites were studied by X-ray diffraction, with the intercalates having an interlayer spacing of 14.5–18.6 Å. Infrared spectroscopy confirmed the presence of characteristic vibration peaks associated with the Gd3+ complexes in the intercalation compounds. The proton relaxivities of the Gd3+ complex-loaded composites were 2 to 5-fold higher in longitudinal relaxivity, and up to 10-fold higher in transverse relaxivity, compared to solutions of the pure complexes. These data demonstrate that the new composites reported here are potentially potent MRI contrast agents
Multiplicity dependence of jet-like two-particle correlations in p-Pb collisions at = 5.02 TeV
Two-particle angular correlations between unidentified charged trigger and
associated particles are measured by the ALICE detector in p-Pb collisions at a
nucleon-nucleon centre-of-mass energy of 5.02 TeV. The transverse-momentum
range 0.7 5.0 GeV/ is examined,
to include correlations induced by jets originating from low
momen\-tum-transfer scatterings (minijets). The correlations expressed as
associated yield per trigger particle are obtained in the pseudorapidity range
. The near-side long-range pseudorapidity correlations observed in
high-multiplicity p-Pb collisions are subtracted from both near-side
short-range and away-side correlations in order to remove the non-jet-like
components. The yields in the jet-like peaks are found to be invariant with
event multiplicity with the exception of events with low multiplicity. This
invariance is consistent with the particles being produced via the incoherent
fragmentation of multiple parton--parton scatterings, while the yield related
to the previously observed ridge structures is not jet-related. The number of
uncorrelated sources of particle production is found to increase linearly with
multiplicity, suggesting no saturation of the number of multi-parton
interactions even in the highest multiplicity p-Pb collisions. Further, the
number scales in the intermediate multiplicity region with the number of binary
nucleon-nucleon collisions estimated with a Glauber Monte-Carlo simulation.Comment: 23 pages, 6 captioned figures, 1 table, authors from page 17,
published version, figures at
http://aliceinfo.cern.ch/ArtSubmission/node/161
Coordination Polymer Flexibility Leads to Polymorphism and Enables a Crystalline Solid-Vapour Reaction: A Multi-technique Mechanistic Study.
Despite an absence of conventional porosity, the 1D coordination polymer [Ag4 (O2 C(CF2 )2 CF3 )4 (TMP)3 ] (1; TMP=tetramethylpyrazine) can absorb small alcohols from the vapour phase, which insert into AgO bonds to yield coordination polymers [Ag4 (O2 C(CF2 )2 CF3 )4 (TMP)3 (ROH)2 ] (1-ROH; R=Me, Et, iPr). The reactions are reversible single-crystal-to-single-crystal transformations. Vapour-solid equilibria have been examined by gas-phase IR spectroscopy (K=5.68(9)×10(-5) (MeOH), 9.5(3)×10(-6) (EtOH), 6.14(5)×10(-5) (iPrOH) at 295 K, 1 bar). Thermal analyses (TGA, DSC) have enabled quantitative comparison of two-step reactions 1-ROH→1→2, in which 2 is the 2D coordination polymer [Ag4 (O2 C(CF2 )2 CF3 )4 (TMP)2 ] formed by loss of TMP ligands exclusively from singly-bridging sites. Four polymorphic forms of 1 (1-A(LT) , 1-A(HT) , 1-B(LT) and 1-B(HT) ; HT=high temperature, LT=low temperature) have been identified crystallographically. In situ powder X-ray diffraction (PXRD) studies of the 1-ROH→1→2 transformations indicate the role of the HT polymorphs in these reactions. The structural relationship between polymorphs, involving changes in conformation of perfluoroalkyl chains and a change in orientation of entire polymers (A versus B forms), suggests a mechanism for the observed reactions and a pathway for guest transport within the fluorous layers. Consistent with this pathway, optical microscopy and AFM studies on single crystals of 1-MeOH/1-A(HT) show that cracks parallel to the layers of interdigitated perfluoroalkyl chains develop during the MeOH release/uptake process
A feasibility study exploring the role of pre-operative assessment when examining the mechanism of ‘chemo-brain’ in breast cancer patients
Background: Women receiving chemotherapy treatment for breast cancer may experience problems with their memory and attention (cognition), which is distressing and interferes with quality of life. It is unclear what causes or contributes to the problems they report: psychological distress, fatigue, coping style, or specific biological changes for example to pro inflammatory cytokines. Research shows however, that approximately a third of women with breast cancer perform poorly on tests of cognition before commencing chemotherapy. We aimed to examine the acceptability and relevance of pre-surgical assessments (bloods, brain imaging, cognitive tests and self-report questionnaires) when investigating the phenomenon of ‘chemo-brain’ and investigate whether inflammatory markers mediate chemotherapy-induced neuropsychological impairments in women treated for breast cancer.
Methods: Women with early stage breast cancer completed neuropsychological and quality of life assessments at T1 (pre-surgery), T2 (post-surgery before chemotherapy) and T3 (6 months later). Blood cytokine levels were measured at the same time points and brain imaging was performed at T1 and T3.
Results: In total, 14/58 women participated (8 chemotherapy, 6 non-chemotherapy). Prior to the start of chemotherapy a decline in cognitive performance compared to baseline was observed in one participant. At T3 women who received chemotherapy reported poorer quality of life and greater fatigue. Increases in soluble tumour necrosis factor receptor II (sTNFRII), interleukin-6, interleukin-10 and vascular endothelial growth factor occurred post chemotherapy only. Levels of sTNFRII were inversely correlated with grey matter volume (GMV) of the right posterior insula in both groups. At T3, the chemotherapy group displayed a greater reduction in GMV in the subgenual and dorsal anterior cingulate, and the inferior temporal gyrus.
Conclusions: Pre-operative recruitment to the study was challenging; however, the lack of significant changes in blood cytokine levels and neuropsychological tests at T2 implies that post surgery may be a valid baseline assessment, but this needs further investigation in a larger study. The preliminary results support the hypothesis that chemotherapy induced fatigue is mediated by a change in peripheral cytokine levels which could explain some symptoms of ‘chemo brain’ experienced by patients
Seminario de Economía Mexicana
Serie de ponencias referentes al Seminario de Economía Mexicana. Memorias del Seminario de Economía Mexicana de 199
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