Estimados lectores y colaboradores de Biodiversity and Natural History

Welcome to the first issue of Biodiversity and Natural History, a peer-reviewed, open-access and electronic journal published by the Centro de Estudios en Biodiversidad de Chile (Center for Studies in Biodiversity). The journal was created in 2009 under the name of Boletín de Biodiversidad de Chile with the aim of being a contribution to the dissemination of the Chilean biodiversity and natural history. True to its original purpose, the journal only published Chilean manuscripts in the early years. However, as time went by, the journal also started to receive and publish manuscripts coming from elsewhere in the planet. Accordingly, the journal gradually became an international channel for the scientific promotion and dissemination of biodiversity and natural history and thus, the name of the journal, as well as its original scope and goals were no longer representative.Because of this, in late 2014 the Editorial Board decided to change the original name of the journal to Biodiversity and Natural History a..

A 83Krm Source for Use in Low-background Liquid Xenon Time Projection Chambers

We report the testing of a charcoal-based Kr-83m source for use in calibrating a low background two-phase liquid xenon detector. Kr-83m atoms produced through the decay of Rb-83 are introduced into a xenon detector by flowing xenon gas past the Rb-83 source. 9.4 keV and 32.1 keV transitions from decaying 83Krm nuclei are detected through liquid xenon scintillation and ionization. The characteristics of the Kr-83m source are analyzed and shown to be appropriate for a low background liquid xenon detector. Introduction of Kr-83m allows for quick, periodic calibration of low background noble liquid detectors at low energy.Comment: Updated to version submitted to JINS

Calibration of a Liquid Xenon Detector with Kr-83m

We report the preparation of a Kr-83m source and its subsequent use in calibrating a liquid xenon detector. Kr-83m atoms were produced through the decay of Rb-83 atoms trapped in zeolite molecular sieve and were then introduced into liquid xenon. Decaying Kr-83m nuclei were detected through liquid xenon scintillation. Conversion electrons with energies of 9.4 keV and 32.1 keV from the decay of Kr-83m were both observed. This calibration source will allow the characterization of the scintillation and ionization response of noble liquid detectors at low energies, highly valuable for the search for WIMP dark matter. Kr-83m may also be useful for measuring fluid flow dynamics, both to understand purification in noble liquid-based particle detectors, as well as for studies of classical and quantum turbulence in superfluid helium.Comment: Minor edits to match published versio

Causal effects of PetroCaribe on sustainable development: a synthetic control analysis

We examine the causal effects of the energy subsidy programme PetroCaribe in the three dimensions of sustainable development: economic, social and environmental. We use the synthetic control method to construct a counterfactual and compare it to the outcomes of the beneficiary countries and thus estimate the magnitude and direction of the PetroCaribe effect. PetroCaribe had a positive effect on economic growth in most of the beneficiary countries; however, this economic boost was not followed by an improvement in social development. Environmentally, PetroCaribe did not negatively or positively impact the environmental quality of the member countries, in the sense that we do not find a significant effect on the trend of urn:x-wiley:14636786:media:manc12275:manc12275-math-0001 emissions per capita

Ecologia reprodutiva e história natural de Kinosternon herrerai (Testudines: Kinosternidae) no centro de sua distribuição

México alberga 10 especies endémicas de tortugas de barro del género Kinosternon, pero hace falta información de historia natural para la mayoría de ellas. Aquí describimos algunas generalidades de la ecología reproductiva e historia natural de una población de la tortuga Casquito de Herrera, endémica mexicana, K. herrerai en Hidalgo, México. Las hembras y los machos fueron similares en masa corporal y longitud del carapacho, además, las tortugas más grandes y pesadas se movieron más que aquellas más pequeñas y livianas. El tamaño de la puesta varió de uno a seis huevos, con un promedio de 3.4 ± 1.7, y la puesta de huevos ocurrió a temperaturas ambientales entre 15 and 21°C (x̅ = 18.6°C). El tiempo total de anidamiento (desde la selección del nido hasta la ovoposición) duró ca. 37 min y el periodo de incubación fue de 75 días in situ. Estos resultados mejoran nuestra comprensión de los aspectos de historia natural de las tortugas de barro Kinosternon, que son necesarios para llevar a cabo acciones de conservación para preservar todas sus poblaciones.Mexico harbors 10 endemic species of mud turtles of genus Kinosternon, but natural history information is lacking for most of them. Herein we describe some generalities of the reproductive ecology and natural history of one population of the Mexican endemic, Herrera’s mud turtle, K. herrerai from Hidalgo, Mexico. Females and males were similar in body mass and carapace length. Additionally, larger and heavier turtles moved more than smaller and lighter ones. Clutch size varied from one to six eggs, with an average of 3.4 ± 1.7, and egg laying occurred at environmental temperatures between 15 and 21°C (x̅ = 18.6°C). Total nesting time (from selection of nesting site to oviposition) lasted ca. 37 min, and the incubation period was 75 days in situ. These results enhance our understanding of natural history aspects of Kinosternon mud turtles, which are necessary to carry out conservation actions to preserve all of its populations.O México abriga 10 espécies endêmicas de tartarugas-de-lama do gênero Kinosternon, mas faltam informações sobre a história natural da maioria delas. Aqui, descrevemos algumas generalidades da ecologia reprodutiva e da história natural de uma população de Hidalgo da tartaruga-de-lama-de-herrera, K. herrerai, endêmica do México. As fêmeas e os machos eram semelhantes em termos de massa corporal e comprimento da carapaça. Além disso, as tartarugas maiores e mais pesadas se movimentavam mais do que as menores e mais leves. O tamanho da ninhada variou de um a seis ovos, com uma média de 3,4 ± 1,7, e a postura dos ovos ocorreu em temperaturas ambientais entre 15 e 21°C (x̅ = 18,6°C). O tempo total de nidificação (desde a seleção do local de nidificação até a ovipostura) durou cerca de 37 min, e o período de incubação foi de 75 dias in situ. Esses resultados aumentam nossa compreensão dos aspectos da história natural das espécies de Kinosternon, que são necessários para realizar ações de conservação para preservar todas as suas populações

Modelado de la influencia de la microestructura en la microdureza de materiales con recubrimiento

Mediante simulación numérica se estudió la microdureza en un material metálico recubierto con óxido metálico. La simulación consiste de un contacto bidimensional axisimétrico entre un indentador esférico y un sistema sustrato-recubrimiento. Se consideró un sustrato formado por titanio recubierto con otro material más duro a diferentes cargas de indentación y espesores del recubrimiento, considerando dos casos: ambos materiales perfectamente adheridos o los dos materiales interactuando a través de una interfaz cohesiva. Se analizaron los efectos de las propiedades mecánicas de cada material sobre el comportamiento global del sistema, la relacion entre dureza y espesor del recubrimiento, la influencia de fallas locales en la interfaz y de la estructura de granos en sustrato y recubrimiento. Los resultados permitieron obtener correlaciones entre la dureza y las propiedades mecánicas y geométricas del sistema. Se destaca que cuando el recubrimiento es delgado es posible explicar la dispersión en resultados de microdureza en un material recubierto si se tienen en cuanta fallas de adhesión en la interfaz y la estructura de granos en el sustrato.Publicado en: Mecánica Computacional vol. XXXV no.36Facultad de Ingenierí

3D Position Sensitive XeTPC for Dark Matter Search

The technique to realize 3D position sensitivity in a two-phase xenon time projection chamber (XeTPC) for dark matter search is described. Results from a prototype detector (XENON3) are presented.Comment: Presented at the 7th UCLA Symposium on "Sources and Detection of Dark Matter and Dark Energy in the Universe

Constraints on inelastic dark matter from XENON10

It has been suggested that dark matter particles which scatter inelastically from detector target nuclei could explain the apparent incompatibility of the DAMA modulation signal (interpreted as evidence for particle dark matter) with the null results from CDMS-II and XENON10. Among the predictions of inelastically interacting dark matter are a suppression of low-energy events, and a population of nuclear recoil events at higher nuclear recoil equivalent energies. This is in stark contrast to the well-known expectation of a falling exponential spectrum for the case of elastic interactions. We present a new analysis of XENON10 dark matter search data extending to E$_{nr}=75$ keV nuclear recoil equivalent energy. Our results exclude a significant region of previously allowed parameter space in the model of inelastically interacting dark matter. In particular, it is found that dark matter particle masses $m_{\chi}\gtrsim150$ GeV are disfavored.Comment: 8 pages, 4 figure