Education choices in Mexico: using a structural model and a randomized experiment to evaluate Progresa

In this paper we use an economic model to analyse data from a major social experiment, namely PROGRESA in Mexico, and to evaluate its impact on school participation. In the process we also show the usefulness of using experimental data to estimate a structural economic model. The evaluation sample includes data from villages where the program was implemented and where it was not. The allocation was randomised for evaluation purposes. We estimate a structural model of education choices and argue that without such a framework it is impossible to evaluate the effect of the program and, especially, possible changes to its structure. We also argue that the randomized component of the data allows us to identify a more flexible model that is better suited to evaluate the program. We find that the program has a positive effect on the enrollment of children, especially after primary school; this result is well replicated by the parsimonious structural model. We also find that a revenue neutral change in the program that would increase the grant for secondary school children while eliminating for the primary school children would have a substantially larger effect on enrollment of the latter, while having minor effects on the former.

Diversidad y Composición de las comunidades de líquenes en un gradiente altitudinal en la Sierra de Famatina (La Rioja).

Tesina (Grado en Ciencias Biológicas)--Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Lugar de Trabajo: Centro de Ecología y Recursos Naturales Renovables "Dr. Ricardo Luti" - Facultad de Ciencias Exactas, Físicas y Naturales. Universidad Nacional de Córdoba. 2018. 26 h.; tabls.; grafs. Contiene Referencia Bibliográfica.Como objetivo general nos planteamos estudiar como varía la riqueza, diversidad,cobertura y estructura de las comunidades de líquenes a lo largo de un gradiente altitudinal y con respecto a la orientación de las laderas en la Sierra de Famatina. Hemos demostrado que la altura es una variable que modifica todos los patrones comunitarios estudiados. Asimismo la heterogeneidad de hábitat, sintetizada en este trabajo a través de las orientaciones, influye en la estructura y cobertura de líquenes, solo en las alturas más bajas del gradiente. Este trabajo hace un gran aporte a la diversidad de la región, pudiendo incluso aportar información de base para nuevos monitoreos y la posibilidad de observar en nuevos estudios, cómo puede estar influyendo el cambio climático sobre la composición de estas comunidades en las diferentes alturas. En este sentido es relevante considerar que los líquenes son los últimos macro organismos que habitan los pisos de elevación más altos en los sistemas montañosos y por lo tanto su seguimiento en el tiempo permitirá conocer acabadamente el impacto del cambio climático en estos ambientes

Analysis of the role of Granzyme-A in the development of colorectal cancer stem cells

Colorectal cancer is the third leading cause of cancer death worldwide with nearly 150.000 new cases diagnose annually. New therapies have been developed for the last years targeting different proliferation and survival signalling pathways but few advances have been done to avoid relapse in patients. Cancer stem cells are proposed as the main mechanism of resistance in current therapies. These cells have been described as a subset among all the tumour cell populations which have stemness properties such as self-renewal and differentiation capabilities. These features allow them to survive after antitumour treatments and regenerate the entire tumour mass. Also, cancer stem cells have been proposed as the responsible of metastasis. Inflammation in colorectal cancer is a sign of poor prognosis and it has been proposed as the main driver of the tumour progression. Its relation with cancer stem cells has not been clasified yet but pro-inflammatory molecules such as TNF-α or IL-1B are able to activate cancer stem cells-related signalling pathways such as Wnt or Notch pathways. Granzyme-A, a protease released by immune cells, is involved in implication during like bacterial sepsis or arthritis. Our preliminary data indicate it is involved in development of colorectal cancer. The current study analyse the implication of Granzyme-A in the activation of CSCs during inflammation-associated colorectal cancer in a mouse model

New records of Tachybaptus dominicus (Linnaeus, 1766) (Aves, Podicipedidae) south of its currently known distribution in Argentina

We report on 4 records of the Least Grebe, Tachybaptus dominicus (Linnaeus, 1766), to the south of its theoretical distributional limit in Córdoba Province, Argentina. In recent years, these records and others uploaded to citizen science platforms suggest that this species’ distribution extends south of its currently known range.Fil: Castillo, Santiago. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; ArgentinaFil: Costas, Santiago. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; ArgentinaFil: Toledo, Javier Martín. Universidad Nacional de Córdoba; ArgentinaFil: Giaquinta, Adrián. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; Argentin

Factorization method for difference equations of hypergeometric type on nonuniform lattices

We study the factorization of the hypergeometric-type difference equation of Nikiforov and Uvarov on nonuniform lattices. An explicit form of the raising and lowering operators is derived and some relevant examples are given.Ministerio de Ciencia y TecnologíaJunta de AndalucíaUnión Europe

The relative effect of altitude and aspect on saxicolous lichen communities at mountain summits from central-west of Argentina

The altitudinal patterns of lichen communities in altitudinal gradients are very variable. The changes that occur along the mountains depend on climatic factors but also on microsite variables such as substrate type and aspect. The effect of altitude and aspect on richness, cover and composition of saxicolous lichens communities along an elevation gradient in extra Andean mountains from the central-west of Argentina was studied. Rock outcrops on the north and south aspect of three mountain summits distributed between 2,500 and 4,500 m.a.s.l. were sampled. Lichen species present in a 20 × 20 cm square were identified and the relative cover was measured using digital photography. Richness, cover and composition were analyzed through linear models and multivariate analysis. Fifty-eight saxicolous lichen species were identified between the three sites. Richness and cover were maximum at middle altitude. Also compositional differences among communities of each mountain summit were found. Finally, the effect of the aspect was significant at lower altitudes for cover and composition.Fil: Costas, Santiago. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; ArgentinaFil: Canton, Norma Virginia. Universidad Nacional de Chilecito; ArgentinaFil: Rodriguez, Juan Manuel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigaciones Biológicas y Tecnológicas. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Instituto de Investigaciones Biológicas y Tecnológicas; Argentin

The role of Samhd1 in controlling DNA damage and tumour development in in vivo models

Systemic autoimmunity describes a group of detrimental conditions, characterized by loss of immunologic self-tolerance. Pattern recognition receptors (PRR) detect recurrent microbial structures including nucleic acids. Nucleic acid-specific PRRs are not well equipped to discriminate between self and non-self nucleic acids and their aberrant activation leads to autoimmune conditions, driven by chronic activation of the type I interferon (IFN) system. This concept has been established by research on the molecular mechanisms underlying the rare Aicardi-Goutières syndrome (AGS). Loss of function mutations in the gene SAMHD1 cause AGS. SAMHD1 was first described as a deoxyribonucleotide (dNTP) triphosphohydrolase (dNTPase) and its activity is tightly regulated during the cell cycle to ensure the correct cellular supply of dNTPs. Cells decrease SAMHD1 dNTPase activity during S phase where the DNA must be replicated and once the S phase is over, dNTPase activity is restored and the dNTP levels are reduced. Loss of SAMHD1 causes an increase of the cellular dNTP concentration during phases of the cell cycle, a well-known trigger for DNA damage, but its consequences has not been addressed yet thoroughly. Recently, SAMHD1 has been also reported to promote homologous recombination directly at the site of DNA double strand breaks (DSB) upon genotoxic stress. By interacting with the protein CtIP, SAMHD1 helped to coordinate the MRN complex and promotes DSB repair. Loss of SAMHD1 impaired this repair mechanism, causing genome instability. Interestingly, this activity of SAMHD1 has also been recently shown to promote restart of stalled replication forks. Lack of SAMHD1 lead to an increase of stalled replication forks and DSBs. How the different activities of SAMHD1 remain balanced and are activated under specific conditions still remains unknown. Additionally, inactivating mutations in SAMHD1 have recurrently been identified in various types of cancers, raising the question, if the protein might function as a tumour suppressor. However, up to date, no in vivo study has addressed the role of SAMHD1 in preventing DNA damage or cancer development, and its relationship to an uncontrolled type I IFN response. In this work, Samhd1-deficient mice were screened in search for sign of DNA damage and an increase in micronucleated erythrocytes, a hallmark for genome instability, was found in comparison with their littermate controls. This increase was still present upon inactivation of nucleic acid sensing pathways, indicating that it was independent of the status of type I IFN response. HSC competitive transplantation experiments with Samhd1-deficient and control HSCs showed a minor contribution of Samhd1 in maintaining lymphogenesis. Despite these findings, Samhd1-deficient mice do not develop any autoimmune disease nor cancer up to 2 years of observation. Previous reports showed a possible relation between loss of SAMHD1 and p53 activation. We inactivated p53 in Samhd1 ko mice, which resulted in accelerated lethality and an earlier onset of tumour formation when compared with p53 ko mice. However, the underlying molecular mechanisms of both observations remains to be fully elucidated. In contrast to the results with p53, inactivation of DNA mismatch repair (knockout of Pms2) in Samhd1 ko mice, had no effect on the tumour-free survival in comparison with Pms2 ko mice. Inactivation of either p53 or Pms2 in Samhd1 ko mice did not altered the spontaneous type I IFN activation. To understand better the different activities described for Samhd1 – dNTPase and DNA damage-related activities –, the dNTPase-inactivating mutations HD238/239AA were knocked into the endogenous Samhd1 gene using CRISPR/Cas9. Using this mouse model, we found that the mutant Samhd1 protein is rapidly degraded in the proteasome, leading to almost complete absence of Samhd1 in the new mouse strain, as seen in patient with similar mutation in Samhd1. These results demonstrated that in patients with mutations in the dNTPase domain, the phenotype is most likely driven by a complete absence of Samhd1 and only by a selective loss of the dNTPase activity. Our work provides new insights in the understanding of Samhd1 as regulator of DNA damage and establishes new ground for further research on the link between DNA damage and type I IFN response

Local adaptation to hummingbirds and bees in Salvia stachydifolia : insights into pollinator shifts in a Southern Andean sage

Differences among populations in pollinator assemblages can lead to local adaptation mosaics in which plants evolve different floral morphologies and attractive traits. Mountain habitats may promote local adaptation because of differences in environmental conditions with altitude, causing changes in pollinators, and because mountaintops can act as isolated habitats. We studied if the differences in floral shape, size and nectar traits in Salvia stachydifolia can be attributed to variations in the relative contribution of hummingbirds and insects.• Methods We studied eight populations of S. stachydifolia in natural and under common garden conditions, to assess whether population differences have a genetic component. We recorded pollinators, their behaviour and visitation rates, and characterized pollinator assemblages. In addition, we measured nectar volume and concentration, and collected flowers to describe floral shape and size variation using geometric morphometric methods. We then applied an unsupervised learning algorithm to identify ecotypes based on morphometric traits. Finally, we explored whether populations with different pollinator assemblages had different climatic and/or elevationpreferences.• Key Results We found that variation in the identity of the main pollinators was associated with differences among populations in all traits, as expected under a local adaptation scenario. These differences persisted in the common garden, suggesting that they were not due to phenotypic plasticity. We found S. stachydifolia populations were pollinated either by bees, by hummingbirds or had mixed pollination. We identified two ecotypes that correspond to the identity of the main pollinator guilds, irrespective of climate or altitude.• Conclusions Variation in S. stachydifolia floral traits did not follow any evident association with bioclimatic factors, suggesting that populations may have diverged as the product of historical isolation on mountaintops. We suggest that differences among populations point to incipient speciation and an ongoing pollinator shift.Fil: Izquierdo, Juliana Verónica. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; ArgentinaFil: Costas, Santiago. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; ArgentinaFil: Castillo, Santiago. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; ArgentinaFil: Baranzelli, Matias Cristian. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; ArgentinaFil: Sazatornil, Federico David. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; ArgentinaFil: Benitez Vieyra, Santiago Miguel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; Argentin

A q-analog of the Racah polynomials and the q-algebra SUq(2)

We study some q-analogues of the Racah polynomials and some of their applications in the theory of representation of quantum algebras.Dirección General de Enseñanza SuperiorPlan Andaluz de Investigación (Junta de Andalucía)Russian Foundation of Basic researc

Factorization of the hypergeometric-type difference equation on the non-uniform lattices: dynamical algebra

We argue that one can factorize the difference equation of hypergeometric type on the nonuniform lattices in general case. It is shown that in the most cases of q-linear spectrum of the eigenvalues this directly leads to the dynamical symmetry algebra suq(1, 1), whose generators are explicitly constructed in terms of the difference operators, obtained in the process of factorization. Thus all models with the q-linear spectrum (some of them, but not all, previously considered in a number of publications) can be treated in a unified form.Ministerio de Ciencia y TecnologíaJunta de AndalucíaDirección General de Asuntos del Personal Académico (Universidad Nacional Autónoma de México