28 research outputs found
Are Conditional Cash Transfers Effective in Urban Areas? Evidence from Mexico
Conditional cash transfer (CCT) programs have spread worldwide as a new form of social assistance for the poor. Previous evaluations of CCT programs focus mainly on rural settings, and little is known about their effects in urban areas. This paper studies the short-term (one and two-year) effects of the Mexican Oportunidades CCT program on urban children/youth. The program provides financial incentives for children/youth to attend school and for family members to visit health clinics. To participate, families had to sign up for the program and be deemed eligible. Difference-in-difference propensity score matching estimates indicate that the program is successful in increasing school enrollment, schooling attainment and time devoted to homework and in decreasing working rates of boys.conditional cash transfer programs, matching estimators, program evaluation
Molecular dissection of the migrating posterior lateral line primordium during early development in zebrafish
<p>Abstract</p> <p>Background</p> <p>Development of the posterior lateral line (PLL) system in zebrafish involves cell migration, proliferation and differentiation of mechanosensory cells. The PLL forms when cranial placodal cells delaminate and become a coherent, migratory primordium that traverses the length of the fish to form this sensory system. As it migrates, the primordium deposits groups of cells called neuromasts, the specialized organs that contain the mechanosensory hair cells. Therefore the primordium provides both a model for studying collective directional cell migration and the differentiation of sensory cells from multipotent progenitor cells.</p> <p>Results</p> <p>Through the combined use of transgenic fish, Fluorescence Activated Cell Sorting and microarray analysis we identified a repertoire of key genes expressed in the migrating primordium and in differentiated neuromasts. We validated the specific expression in the primordium of a subset of the identified sequences by quantitative RT-PCR, and by <it>in situ </it>hybridization. We also show that interfering with the function of two genes, <it>f11r </it>and <it>cd9b</it>, defects in primordium migration are induced. Finally, pathway construction revealed functional relationships among the genes enriched in the migrating cell population.</p> <p>Conclusions</p> <p>Our results demonstrate that this is a robust approach to globally analyze tissue-specific expression and we predict that many of the genes identified in this study will show critical functions in developmental events involving collective cell migration and possibly in pathological situations such as tumor metastasis.</p
A high-throughput chemically induced inflammation assay in zebrafish
Artículo de publicación ISIBackground: Studies on innate immunity have benefited from the introduction of zebrafish as a model system.
Transgenic fish expressing fluorescent proteins in leukocyte populations allow direct, quantitative visualization of an
inflammatory response in vivo. It has been proposed that this animal model can be used for high-throughput
screens aimed at the identification of novel immunomodulatory lead compounds. However, current assays require
invasive manipulation of fish individually, thus preventing high-content screening.
Results: Here we show that specific, noninvasive damage to lateral line neuromast cells can induce a robust acute
inflammatory response. Exposure of fish larvae to sublethal concentrations of copper sulfate selectively damages
the sensory hair cell population inducing infiltration of leukocytes to neuromasts within 20 minutes. Inflammation
can be assayed in real time using transgenic fish expressing fluorescent proteins in leukocytes or by histochemical
assays in fixed larvae. We demonstrate the usefulness of this method for chemical and genetic screens to detect
the effect of immunomodulatory compounds and mutations affecting the leukocyte response. Moreover, we
transformed the assay into a high-throughput screening method by using a customized automated imaging and
processing system that quantifies the magnitude of the inflammatory reaction.
Conclusions: This approach allows rapid screening of thousands of compounds or mutagenized zebrafish for
effects on inflammation and enables the identification of novel players in the regulation of innate immunity and
potential lead compounds toward new immunomodulatory therapies. We have called this method the chemically
induced inflammation assay, or ChIn assay.This work was supported by
grants to MA from Fondecyt (1070867), FONDAP (15090007), ICM (P06-039F),
CORFO-Innova (09MCSS-6705), DFG-Conicyt 075-2009; to CD from UNAB (DI-
01-09/1) and Fondecyt (24090004); to UL from Dopaminet (EU FP7 223744);
and to CG by a Marie Curie International Reintegration Grant (EU FP7;
PIRG07-GA-2010-267552)
Hidrogeles multicomponentes basados en vinilpirrolidona y su aplicación en ingeniería de tejidos y/o medicina regenerativa
Hidrogel con estructura de red polimérica
multicomponente entrecruzada, caracterizado porque
comprende: a) unidades derivadas de vinilpirrolidona
(V) y unidades derivadas de un monómero alquénico
aniónico o anionizable (A), donde las relaciones de
reactividad en copolimerización radical binaria de (V)
y (A) tienen valores máximo y mínimo de 0.5
respectivamente; y b) unidades derivadas de al
menos un entrecruzante; siempre que el o los
entrecruzantes sean i) dos entrecruzantes E1 y E2,
donde E1 presenta homología al menos parcial
respecto a (A) y E2 presenta homología al menos
parcial respecto a (V); o ii) un entrecruzante E3 que
presenta homología respecto a (A) y (V).
Procedimiento de obtención del mencionado hidrogel
que comprende poner en contacto los monómeros (A)
y (V) con los entrecruzantes E1 y E2, o el
entrecruzante E3, en condiciones de polimerización
radicalaria. Uso del hidrogel en aplicaciones
biológicas, biomédicas o biotecnológicas que
requieran una interacción no tóxica hidrogel-célula.Peer reviewedConsejo Superior de investigaciones Científicas, Universidad Complutense de MadridB1 Patente sin examen previ
Transcriptional signature of accessory cells in the lateral line, using the Tnk1bp1:EGFP transgenic zebrafish line
<p>Abstract</p> <p>Background</p> <p>Because of the structural and molecular similarities between the two systems, the lateral line, a fish and amphibian specific sensory organ, has been widely used in zebrafish as a model to study the development/biology of neuroepithelia of the inner ear. Both organs have hair cells, which are the mechanoreceptor cells, and supporting cells providing other functions to the epithelium. In most vertebrates (excluding mammals), supporting cells comprise a pool of progenitors that replace damaged or dead hair cells. However, the lack of regenerative capacity in mammals is the single leading cause for acquired hearing disorders in humans.</p> <p>Results</p> <p>In an effort to understand the regenerative process of hair cells in fish, we characterized and cloned an <it>egfp </it>transgenic stable fish line that trapped <it>tnks1bp1</it>, a highly conserved gene that has been implicated in the maintenance of telomeres' length. We then used this Tg(<it>tnks1bp1</it>:EGFP) line in a FACsorting strategy combined with microarrays to identify new molecular markers for supporting cells.</p> <p>Conclusions</p> <p>We present a Tg(<it>tnks1bp1</it>:EGFP) stable transgenic line, which we used to establish a transcriptional profile of supporting cells in the zebrafish lateral line. Therefore we are providing a new set of markers specific for supporting cells as well as candidates for functional analysis of this important cell type. This will prove to be a valuable tool for the study of regeneration in the lateral line of zebrafish in particular and for regeneration of neuroepithelia in general.</p
The Atacama Cosmology Telescope: Cosmological parameters from three seasons of data
We present constraints on cosmological and astrophysical parameters from
high-resolution microwave background maps at 148 GHz and 218 GHz made by the
Atacama Cosmology Telescope (ACT) in three seasons of observations from 2008 to
2010. A model of primary cosmological and secondary foreground parameters is
fit to the map power spectra and lensing deflection power spectrum, including
contributions from both the thermal Sunyaev-Zeldovich (tSZ) effect and the
kinematic Sunyaev-Zeldovich (kSZ) effect, Poisson and correlated anisotropy
from unresolved infrared sources, radio sources, and the correlation between
the tSZ effect and infrared sources. The power ell^2 C_ell/2pi of the thermal
SZ power spectrum at 148 GHz is measured to be 3.4 +\- 1.4 muK^2 at ell=3000,
while the corresponding amplitude of the kinematic SZ power spectrum has a 95%
confidence level upper limit of 8.6 muK^2. Combining ACT power spectra with the
WMAP 7-year temperature and polarization power spectra, we find excellent
consistency with the LCDM model. We constrain the number of effective
relativistic degrees of freedom in the early universe to be Neff=2.79 +\- 0.56,
in agreement with the canonical value of Neff=3.046 for three massless
neutrinos. We constrain the sum of the neutrino masses to be Sigma m_nu < 0.39
eV at 95% confidence when combining ACT and WMAP 7-year data with BAO and
Hubble constant measurements. We constrain the amount of primordial helium to
be Yp = 0.225 +\- 0.034, and measure no variation in the fine structure
constant alpha since recombination, with alpha/alpha0 = 1.004 +/- 0.005. We
also find no evidence for any running of the scalar spectral index, dns/dlnk =
-0.004 +\- 0.012.Comment: 26 pages, 22 figures. This paper is a companion to Das et al. (2013)
and Dunkley et al. (2013). Matches published JCAP versio
Phoenix Is Required for Mechanosensory Hair Cell Regeneration in the Zebrafish Lateral Line
In humans, the absence or irreversible loss of hair cells, the sensory mechanoreceptors in the cochlea, accounts for a large majority of acquired and congenital hearing disorders. In the auditory and vestibular neuroepithelia of the inner ear, hair cells are accompanied by another cell type called supporting cells. This second cell population has been described as having stem cell-like properties, allowing efficient hair cell replacement during embryonic and larval/fetal development of all vertebrates. However, mammals lose their regenerative capacity in most inner ear neuroepithelia in postnatal life. Remarkably, reptiles, birds, amphibians, and fish are different in that they can regenerate hair cells throughout their lifespan. The lateral line in amphibians and in fish is an additional sensory organ, which is used to detect water movements and is comprised of neuroepithelial patches, called neuromasts. These are similar in ultra-structure to the inner ear's neuroepithelia and they share the expression of various molecular markers. We examined the regeneration process in hair cells of the lateral line of zebrafish larvae carrying a retroviral integration in a previously uncharacterized gene, phoenix (pho). Phoenix mutant larvae develop normally and display a morphologically intact lateral line. However, after ablation of hair cells with copper or neomycin, their regeneration in pho mutants is severely impaired. We show that proliferation in the supporting cells is strongly decreased after damage to hair cells and correlates with the reduction of newly formed hair cells in the regenerating phoenix mutant neuromasts. The retroviral integration linked to the phenotype is in a novel gene with no known homologs showing high expression in neuromast supporting cells. Whereas its role during early development of the lateral line remains to be addressed, in later larval stages phoenix defines a new class of proteins implicated in hair cell regeneration
Clonal chromosomal mosaicism and loss of chromosome Y in elderly men increase vulnerability for SARS-CoV-2
The pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2, COVID-19) had an estimated overall case fatality ratio of 1.38% (pre-vaccination), being 53% higher in males and increasing exponentially with age. Among 9578 individuals diagnosed with COVID-19 in the SCOURGE study, we found 133 cases (1.42%) with detectable clonal mosaicism for chromosome alterations (mCA) and 226 males (5.08%) with acquired loss of chromosome Y (LOY). Individuals with clonal mosaic events (mCA and/or LOY) showed a 54% increase in the risk of COVID-19 lethality. LOY is associated with transcriptomic biomarkers of immune dysfunction, pro-coagulation activity and cardiovascular risk. Interferon-induced genes involved in the initial immune response to SARS-CoV-2 are also down-regulated in LOY. Thus, mCA and LOY underlie at least part of the sex-biased severity and mortality of COVID-19 in aging patients. Given its potential therapeutic and prognostic relevance, evaluation of clonal mosaicism should be implemented as biomarker of COVID-19 severity in elderly people. Among 9578 individuals diagnosed with COVID-19 in the SCOURGE study, individuals with clonal mosaic events (clonal mosaicism for chromosome alterations and/or loss of chromosome Y) showed an increased risk of COVID-19 lethality
La renovación de la palabra en el bicentenario de la Argentina : los colores de la mirada lingüística
El libro reúne trabajos en los que se exponen resultados de investigaciones presentadas por investigadores de Argentina, Chile, Brasil, España, Italia y Alemania en el XII Congreso de la Sociedad Argentina de Lingüística (SAL), Bicentenario: la renovación de la palabra, realizado en Mendoza, Argentina, entre el 6 y el 9 de abril de 2010. Las temáticas abordadas en los 167 capítulos muestran las grandes líneas de investigación que se desarrollan fundamentalmente en nuestro país, pero también en los otros países mencionados arriba, y señalan además las áreas que recién se inician, con poca tradición en nuestro país y que deberían fomentarse. Los trabajos aquí publicados se enmarcan dentro de las siguientes disciplinas y/o campos de investigación: Fonología, Sintaxis, Semántica y Pragmática, Lingüística Cognitiva, Análisis del Discurso, Psicolingüística, Adquisición de la Lengua, Sociolingüística y Dialectología, Didáctica de la lengua, Lingüística Aplicada, Lingüística Computacional, Historia de la Lengua y la Lingüística, Lenguas Aborígenes, Filosofía del Lenguaje, Lexicología y Terminología
Search for eccentric black hole coalescences during the third observing run of LIGO and Virgo
Despite the growing number of confident binary black hole coalescences observed through gravitational waves so far, the astrophysical origin of these binaries remains uncertain. Orbital eccentricity is one of the clearest tracers of binary formation channels. Identifying binary eccentricity, however, remains challenging due to the limited availability of gravitational waveforms that include effects of eccentricity. Here, we present observational results for a waveform-independent search sensitive to eccentric black hole coalescences, covering the third observing run (O3) of the LIGO and Virgo detectors. We identified no new high-significance candidates beyond those that were already identified with searches focusing on quasi-circular binaries. We determine the sensitivity of our search to high-mass (total mass M>70 M⊙) binaries covering eccentricities up to 0.3 at 15 Hz orbital frequency, and use this to compare model predictions to search results. Assuming all detections are indeed quasi-circular, for our fiducial population model, we place an upper limit for the merger rate density of high-mass binaries with eccentricities 0<e≤0.3 at 0.33 Gpc−3 yr−1 at 90\% confidence level