109 research outputs found

    Geometric structures on loop and path spaces

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    Is is known that the loop space associated to a Riemannian manifold admits a quasi-symplectic structure. This article shows that this structure is not likely to recover the underlying Riemannian metric by proving a result that is a strong indication of the "almost" independence of the quasi-symplectic structure with respect to the metric. Finally conditions to have contact structures on these spaces are studied.Comment: Final version. To appear in Proceedings of Math. Sci. Indian Academy of Science

    Neonatal hypothyroxinemia: effects of iodine intake and premature birth

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    9 pages, 7 figures, 3 tables.We have investigated the effects of iodine (I) intake on urinary I excretion in preterm (PT) babies up to 2 months after birth and its effect on serum T4, free T4 (FT4), T3, TSH, and thyroglobulin (Tg) levels compared to those in term (T) newborns. Very premature and very sick infants were in negative I balance for the first weeks after birth. Later, these same infants, as well as the other PT and T newborns, were in positive balance; 75- 80% of the ingested I was not accounted for in the urine. The urinary I levels of PT and T neonates cannot be equated to their I intakes. T4, FT4, and T3 levels in PT and T neonates increased with postmenstrual age, whereas Tg decreased and TSH did not change. Serum FT4, T3, Tg, and TSH levels in PT neonates were affected negatively, independently from age, by a low I intake. PT birth also affected T4, FT4, and Tg negatively, independently from I intake and postmenstrual age, for at least 6-8 weeks after birth. Care should be taken to avoid I deficiency in PT neonates. However, even when I intake is adequate, PT newborns are hypothyroxinemic compared to T babies during an important period of brain development. This suggests the possible convenience of interventions that might mimic the intrauterine hormone environment and accelerate maturation.This work was supported by the Heinz-Koch Foundation (Milupa, Spain) and the Fondo de Investigaciones Sanitarias (FIS Grant 92/0888 and Fellowship 92/5351 to S.A.).Peer reviewe

    Weak and strong fillability of higher dimensional contact manifolds

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    For contact manifolds in dimension three, the notions of weak and strong symplectic fillability and tightness are all known to be inequivalent. We extend these facts to higher dimensions: in particular, we define a natural generalization of weak fillings and prove that it is indeed weaker (at least in dimension five),while also being obstructed by all known manifestations of "overtwistedness". We also find the first examples of contact manifolds in all dimensions that are not symplectically fillable but also cannot be called overtwisted in any reasonable sense. These depend on a higher-dimensional analogue of Giroux torsion, which we define via the existence in all dimensions of exact symplectic manifolds with disconnected contact boundary.Comment: 68 pages, 5 figures. v2: Some attributions clarified, and other minor edits. v3: exposition improved using referee's comments. Published by Invent. Mat

    Almost holomorphic embeddings in Grassmannians with applications to singular symplectic submanifolds

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    In this paper we use Donaldson's approximately holomorphic techniques to build embeddings of a closed symplectic manifold with symplectic form of integer class in the Grassmannians Gr(r, N). We assure that these embeddings are asymptotically holomorphic in a precise sense. We study first the particular case of CPN obtaining control on N and we improve in a sense a classical result about symplectic embeddings. The main reason of our Study is the construction of singular determinantal submanifolds as the intersection of the embedding with certain "generalized Schubert cycles" defined on a product of Grassmannians. It is shown that the symplectic type of these submanifolds is quite more general that the ones obtained by Donaldson and Auroux,as zeroes of "very ample" vector bundles

    Active interventions in hypercholeteroloemia patiens with high cardiovascular risk in primary care

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    Introduction: Hypercholesterolemia is a major modifiable risk factors for cardiovascular disease (CVD). Its reduction reduces morbidity and mortality from ischemic heart disease and CVD in general, primary prevention and secondary prevention especially. Objective: To determine whether a notarized and intensive clinical practice can overcome inertia and achieve the therapeutic goal (OT) LDL-C &lt;100 mg &lt;dL in high-risk patients attended in Primary Care (PC) in our country. Methodology: epidemiological, prospective, multicenter study conducted in centers of different ACs By AP consecutive sampling 310 patients at high cardiovascular risk (diabetic or established CVD) previously treated with statins, which did not reach the OT included c-LDL. Results: The study subjects had a mean age of 65.2 years, of which 60.32% were male. The 41.64% had a previous EVC, acute myocardial infarction (20.33%), angina (16.07%), stroke /TIA (9.19%), arthropathy (5.25%), diabetes (70 , 87%), hypertension (71.01%), and abdominal obesity (69.62%). The 43.57% (95% CI: 37,21; 50,08) of patients who performed the 2nd visit (241) got the OT. 62.50% (95% CI: 55.68, 68.98) of those who took the 3rd (216) got the OT. Finally, 77.56% (95% CI: 72.13, 83.08) patients who performed the last visit (205) got the OT. Throughout the study there was a reduction in LDL-C levels from 135.6 mg /dL at baseline, 107.4 mg /dL in the 2nd visit, 97.3 mg /dL in the 3rd visit, up to 90.7 mg /dL at the final visit (p &lt;0.0001) The increase in HDL-C from baseline (50.9 mg /dL) and final (53.6 mg /dL) was also significant (p = 0.013). Conclusions: The reassessment and intensification of treatment in patients at high cardiovascular risk treated in primary care, applying the indications of the guides, achieves the OT in more than three quarters of the previously uncontrolled within half a year. These results should encourage us to overcome the therapeutic inertia in the control of CVD by early and energetic performance against hypercholesterolemia.Introducción: La hipercolesterolemia es uno de los principales factores de riesgo modificables de la enfermedad cardiovascular (ECV). Su reducción disminuye la morbimortalidad por cardiopatía isquémica y ECV en general, en prevención primaria y en prevención secundaria especialmente. Objetivo: Comprobar si una práctica clínica protocolizada e intensiva permite vencer la inercia y alcanzar el objetivo terapéutico (OT) de c-LDL < 100 mg/dL en pacientes de alto riesgo asistidos en Atención Primaria (AP) de nuestro país. Metodología: Estudio epidemiológico, prospectivo, multicentrico, realizado en Centros de AP de diferentes CC.AA. Mediante muestreo consecutivo se incluyeron 310 pacientes de alto riesgo cardiovascular (diabéticos o con ECV establecida), tratados previamente con estatinas, que no alcanzaban el OT de c-LDL. Resultados: Los sujetos del estudio tenían una edad media de 65,2 años, de los que el 60,32% eran varones. El 41,64% presentaba un EVC previo, infarto agudo de miocardio (20,33%), angina (16,07%), ictus/AIT (9,19%), artropatía (5,25%), diabetes (70,87%), hipertensión (71,01%), y obesidad abdominal (69,62%). El 43,57% (IC95%: 37,21; 50,08) de los pacientes que realizaron la 2a visita (241) consiguieron el OT. El 62,50% (IC95%: 55,68; 68,98) de los que realizaron la 3a (216) consiguieron el OT. Finalmente, el 77,56% (IC95%: 72,13; 83,08) de los pacientes que realizaron la última visita (205) consiguieron el OT. A lo largo del estudio hubo una reducción de los niveles de c-LDL desde los 135,6 mg/ dL en la visita basal, 107,4 mg/dL en la 2a visita, 97,3 mg/ dL en la 3a visita, hasta los 90,7 mg/dL en la visita final (p < 0,0001) El incremento de c-HDL entre la visita basal (50,9 mg/dL) y la final (53,6 mg/dL) también fue significativo (p = 0,013). Conclusiones: La reevaluación e intensificación del tratamiento en pacientes de alto riesgo cardiovascular atendidos en Atención Primaria, aplicando las indicaciones de las guías, permite alcanzar el OT en más de las tres cuartas partes de los previamente no controlados en el plazo de medio año. Estos resultados nos deben estimular a superar la inercia terapéutica en el control de la ECV mediante una actuación precoz y enérgica ante la hipercolesterolemi

    Transcriptome Analysis Reveals Strain-Specific and Conserved Stemness Genes in Schmidtea mediterranea

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    The planarian Schmidtea mediterranea is a powerful model organism for studying stem cell biology due to its extraordinary regenerative ability mediated by neoblasts, a population of adult somatic stem cells. Elucidation of the S. mediterranea transcriptome and the dynamics of transcript expression will increase our understanding of the gene regulatory programs that regulate stem cell function and differentiation. Here, we have used RNA-Seq to characterize the S. mediterranea transcriptome in sexual and asexual animals and in purified neoblast and differentiated cell populations. Our analysis identified many uncharacterized genes, transcripts, and alternatively spliced isoforms that are differentially expressed in a strain or cell type-specific manner. Transcriptome profiling of purified neoblasts and differentiated cells identified neoblast-enriched transcripts, many of which likely play important roles in regeneration and stem cell function. Strikingly, many of the neoblast-enriched genes are orthologs of genes whose expression is enriched in human embryonic stem cells, suggesting that a core set of genes that regulate stem cell function are conserved across metazoan species
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