Papers by Leonardo Hernández
Estudios Públicos
Este trabajo presenta una breve descripción del grado de desarrollo de los mercados financieros e... more Este trabajo presenta una breve descripción del grado de desarrollo de los mercados financieros en Chile, en comparación con otros países. Luego de resumir las principales reformas financieras implementadas en el país en las últimas décadas, se destacan las fortalezas y debilidades más importantes de los mercados financieros en Chile. A continuación se analizan los problemas urgentes, en particular la liquidez del mercado accionario, los mercados de derivados financieros y el mercado de capital de riesgo, y se discute si las reformas más recientes y las propuestas resuelven adecuadamente estos problemas.
Journal of Biomedical and Allied Research
The influence of Ca2+ and other divalent cations on contractile responses of slow skeletal muscle... more The influence of Ca2+ and other divalent cations on contractile responses of slow skeletal muscle fibers of the frog (Rana pipiens) under conditions of chronic denervation was investigated.Isometric tension was recorded from slow bundles of normal and denervated cruralis muscle in normal solution and in solutions with free calcium concentration solution or in solutions where other divalent cations (Sr2+, Ni2+, Co2+ or Mn2+) substituted for calcium. In the second week after nerve section, in Ca2+-free solutions, we observed that contractures (evoked from 40 to 80 mM-K+) of non-denervated muscles showed significantly higher tensions (p<0.05), than those from denervated bundles. Likewise, in solutions where calcium was substituted by all divalent cations tested, with exception of Mn2+, the denervated bundles displayed lower tension than non-denervated, also in the second week of denervation. In this case, the Ca2+ substitution by Sr2+ caused the higher decrease in tension, followed ...
Revista de Metalurgia
Sobre la superficie de la aleación de magnesio AZ61 se aplicaron recubrimientos de sol-gel basado... more Sobre la superficie de la aleación de magnesio AZ61 se aplicaron recubrimientos de sol-gel basados en el precursor GPTMS-TMOS, incluyendo como agentes dopantes L-Cysteína y ZrO2 en diferentes concentraciones. Su resistencia a la corrosión se estudió en solución de 0,6M NaCl, por inmersión hasta 14 días. Los patrones de DRX revelaron que el principal producto de corrosión en las superficies recubiertas es Mg(OH)2, mientras que en la de AZ61 no tratada adicionalmente se formaron varios compuestos de Zn con cloro. El ataque de la corrosión localizada en el AZ61 no tratada se manifiesta en forma de grietas y cavernas, mientras que en las superficies recubiertas la corrosión fue principalmente a través de picaduras. Dos métodos electroquímicos no destructivos fueron empleados en este estudio, que contrastan el comportamiento electroquímico del AZ61 recubierto con el de la aleación no recubierta. La tendencia en los cambios del potencial de corrosión en circuito abierto se correlacionó po...
Revista Repertorio de Medicina y Cirugía
La migraña es la cefalea primaria más frecuente en las mujeres y si se suman las diversas fluctua... more La migraña es la cefalea primaria más frecuente en las mujeres y si se suman las diversas fluctuaciones hormonales en el transcurso de la vida, la prevalencia es hasta tres veces más que en los hombres. Varía según la edad sexual siendo muchas veces la menarquia el inicio de la misma, así como la presentación exclusiva o facilitada por el período menstrual, la posmenopausia o el verdadero reto, el embarazo. Cuando mujeres de diferentes edades y tipos de cefalea, consultan, es la experticia y la adecuada orientación clínica inicial las que pueden lograr un diagnóstico oportuno y acertado. La migraña es un dolor de cabeza en los servicios de urgencias, no solo por la complejidad de su manejo en las pacientes gestantes, sino por las pocas opciones terapéuticas disponibles que sean seguras más para el feto que para la madre. El médico se ve obligado a tomar decisiones terapéuticas acertadas, generando mejoría del cuadro clínico y confianza en su paciente. Abordamos entonces el dolor de ...
Revista Repertorio de Medicina y Cirugía
La epilepsia cursa con altas tasas de incidencia y prevalencia; hay más de 50 millones de persona... more La epilepsia cursa con altas tasas de incidencia y prevalencia; hay más de 50 millones de personas diagnosticadas a nivel mundial. Desde los evangelios y durante la edad media y el renacimiento, predominaron los tratamientos mágicos y religiosos ante crisis epilépticas; durante el siglo XX, algunas poblaciones indígenas siguieron manejando esta enfermedad con rituales. Objetivo: revisión ampliada de la literatura sobre la percepción de los indígenas acerca de la epilepsia y sus manifestaciones clínicas. Métodos: revisión documental ampliada de estudios cualitativos y de revisión de tema, publicados entre 1977 y 2013. Resultados: de 73 publicaciones, 50 cumplieron con los criterios de selección, de estas 22 eran revisiones del tema, 11 estudios cualitativos y descriptivos, y 17 documentos conformados por libros, memorias de congresos, monografías y documentos de la Organización Mundial de la Salud seleccionados de las citas bibliográficas de los artículos escogidos. Se encontró que l...
Viruses
Because of its ecological characteristics, the Caxiuanã National Forest (FLONA) is a potential ar... more Because of its ecological characteristics, the Caxiuanã National Forest (FLONA) is a potential area of arbovirus circulation. The present study aimed to investigate the occurrence of arbovirus transmission cycles at FLONA de Caxiuanã. Five field trips were performed to capture mosquitoes and sylvatic vertebrates. For these vertebrates, we attempted viral isolation by cell monolayer inoculation from blood, and hemagglutination inhibition and further seroneutralization assays from sera. For mosquitoes, we performed tests of viral genome detection. A total of 338 vertebrates were captured, and the greatest representative was birds (251/74.26%). A total of 16,725 mosquitoes were captured, distributed among 56 species. There were no viruses isolated by newborn mouse inoculation. Among birds, antibodies against Ilheus virus were the most prevalent. Catu virus, Caraparu virus, and Mucambo virus were the most prevalent among mammals and reptiles. Fragments of Mucambo virus, Ilheus virus, Bu...
Science Advances
Unconventional oil and gas exploration in the United States has experienced a period of rapid gro... more Unconventional oil and gas exploration in the United States has experienced a period of rapid growth, followed by several years of limited production due to falling and low natural gas and oil prices. Throughout this transition, the water use for hydraulic fracturing and wastewater production in major shale gas and oil production regions has increased; from 2011 to 2016, the water use per well increased up to 770%, while flowback and produced water volumes generated within the first year of production increased up to 550%. The water-use intensity (that is, normalized to the energy production) increased in all U.S. shale basins except the Marcellus basin during this transition period. The steady increase of the water footprint of hydraulic fracturing with time implies that future unconventional oil and gas operations will require larger volumes of water for hydraulic fracturing, which will result in larger produced oil and gas wastewater volumes.
Science
A sharp increase in the frequency of earthquakes near Fox Creek, Alberta, began in December 2013 ... more A sharp increase in the frequency of earthquakes near Fox Creek, Alberta, began in December 2013 in response to hydraulic fracturing. Using a hydraulic fracturing database, we explore relationships between injection parameters and seismicity response. We show that induced earthquakes are associated with completions that used larger injection volumes (10 4 to 10 5 cubic meters) and that seismic productivity scales linearly with injection volume. Injection pressure and rate have an insignificant association with seismic response. Further findings suggest that geological factors play a prominent role in seismic productivity, as evidenced by spatial correlations. Together, volume and geological factors account for~96% of the variability in the induced earthquake rate near Fox Creek. This result is quantified by a seismogenic index-modified frequency-magnitude distribution, providing a framework to forecast induced seismicity.
Science Advances
The development of hydraulic fracturing ("fracking") is considered the biggest change to the glob... more The development of hydraulic fracturing ("fracking") is considered the biggest change to the global energy production system in the last half-century. However, several communities have banned fracking because of unresolved concerns about the impact of this process on human health. To evaluate the potential health impacts of fracking, we analyzed records of more than 1.1 million births in Pennsylvania from 2004 to 2013, comparing infants born to mothers living at different distances from active fracking sites and those born both before and after fracking was initiated at each site. We adjusted for fixed maternal determinants of infant health by comparing siblings who were and were not exposed to fracking sites in utero. We found evidence for negative health effects of in utero exposure to fracking sites within 3 km of a mother's residence, with the largest health impacts seen for in utero exposure within 1 km of fracking sites. Negative health impacts include a greater incidence of low-birth weight babies as well as significant declines in average birth weight and in several other measures of infant health. There is little evidence for health effects at distances beyond 3 km, suggesting that health impacts of fracking are highly local. Informal estimates suggest that about 29,000 of the nearly 4 million annual U.S. births occur within 1 km of an active fracking site and that these births therefore may be at higher risk of poor birth outcomes.
Repertorio de Medicina y Cirugía, 2017
Policy Research Working Papers, 2016
The Policy Research Working Paper Series disseminates the findings of work in progress to encoura... more The Policy Research Working Paper Series disseminates the findings of work in progress to encourage the exchange of ideas about development issues. An objective of the series is to get the findings out quickly, even if the presentations are less than fully polished. The papers carry the names of the authors and should be cited accordingly. The findings, interpretations, and conclusions expressed in this paper are entirely those of the authors. They do not necessarily represent the views of the International Bank for Reconstruction and Development/World Bank and its affiliated organizations, or those of the Executive Directors of the World Bank or the governments they represent.
Revista de análisis económico, 2016
This paper analyzes the effects of the 2014-2015 Chilean tax reform on firms' valuation and incen... more This paper analyzes the effects of the 2014-2015 Chilean tax reform on firms' valuation and incentives to retain earnings and finance their operations with equity versus debt. By analyzing the effects of the reform on total taxes paid and cash flows received by investors, the paper concludes that in general the reform reduces the value of firms and lessens the incentives to retain earnings. Also, simulations show that the majority of firms would choose the accrual or 'attributed' tax based system. However, if the latter is not permitted firms will choose debt over equity. The cash-based or semi-integrated system becomes the preferred option only when tax avoidance is possible.
The turbulence in financial markets in Southeast Asia in 1997-98 and the crisis in Mexico in 1994... more The turbulence in financial markets in Southeast Asia in 1997-98 and the crisis in Mexico in 1994-95 have renewed interest among policymakers in the issues of capital account liberalization and fi-nancial sector reform. In all the East Asian cases and in Mexico, as well as in many ...
Repertorio de Medicina y Cirugía, 2016
Breast Cancer: Basic and Clinical Research, 2016
NGcGM3 ganglioside is a tumor-specific antigen expressed in human breast tumors. The NGcGM3/VSSP ... more NGcGM3 ganglioside is a tumor-specific antigen expressed in human breast tumors. The NGcGM3/VSSP vaccine, consisting in very small-sized proteoliposomes (VSSP) obtained by the incorporation of NGcGM3 into the outer membrane protein complex of Neisseria meningitidis, has been previously tested in a Phase II trial in patients with metastatic breast cancer (MBC) but emulsified with Montanide ISA 51. An Expanded Access study was carried out in MBC patients aiming to find if a nonemulsive formulation of NGcGM3/VSSP, without Montanide ISA 51, could be more safe and effective. A total of 104 patients were vaccinated with the nonemulsive formulation (900 μg), subcutaneously (SC), or with the emulsive formulation (200 μg), intramuscularly (IM). An intent-to-treat analysis of efficacy was performed with all patients, and 93 patients were split off according to the site of metastases (visceral/nonvisceral). Of note, SC-treated patients exhibited a superior median overall survival (OS) than IM-treated patients (23.6 vs. 8.2 months; log rank P = 0.001). Even though in the subset of patients with nonvisceral metastases SC vaccination duplicated the median OS compared to the alternative option (31.6 vs. 16.5 months), this difference did not reach statistical significance (log rank P = 0.118). Curiously, in patients with visceral metastases, the advantage of the nonemulsive formulation was more apparent (median OS 21.0 vs. 6.2 months; log rank P = 0.005). The vaccine was safe for both formulations.
CNS & Neurological Disorders - Drug Targets, 2016
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Papers by Leonardo Hernández