Description: This article discusses the characterization of sub-nuclear changes in Caenorhabditis elegans embryos exposed to brief, intermediate and long-term anoxia to analyze anoxia-induced cell cycle arrest. Abstract: Background: The soil nematode C. elegans survives oxygen-deprived conditions (anoxia; <.001 kPa O₂) by entering into a state of suspended animation in which cell cycle progression reversibly arrests. The majority of blastomeres of embryos exposed to anoxia arrest at interphase, prophase and metaphase. The spindle checkpoint proteins SAN-1 and MDF-2 are required for embryos to survive 24 hours of anoxia. To further investigate the mechanism of cell-cycle arrest, the authors examined and compared sub-nuclear changes such as chromatin localization pattern, post-translational modification of histone H3, spindle microtubules, and localization of the spindle checkpoint protein SAN-1 with respect to various anoxia exposure time points. To ensure analysis of embryos exposed to anoxia and not post-anoxic recovery the authors fixed all embryos in an anoxia glove box chamber. Results: Embryos exposed to brief periods to anoxia (30 minutes) contain prophase blastomeres with chromosomes in close proximity to the nuclear membrane, condensation of interphase chromatin and metaphase blastomeres with reduced spindle microtubules density. Embryos exposed to longer periods of anoxia (1-3 days) display several characteristics including interphase ...

Description: This article discusses building a Chilean network for long-term socio-ecological research. Abstract: Since their formal inception in 1980, long-term ecological research (LTER) programs have served as a successful organizing framework to create research agendas and funding mechanisms that allow scientists to address meaningful ecological phenomena at the scales they occur. In its 30 years of existence, LTER has expanded its geographic range (currently the International LTER network has more than 40 country members with sites on every continent) and disciplinary foci (principally encompassing the natural and social sciences and leading some to call for a name change to long-term socio-ecological research efforts exist in both Chile and Argentina, and in 2008, the Institute of Ecology and Biodiversity launched Chile's first concerted effort to link three existing sites (Fray Jorge Forest National Park -33° S, Senda Darwin Biological Station - 43° S, and Omora Ethnobotanical Park - 55° S). Here, the authors present a special feature of the Revista Chilena de Historia Natural, dedicated to LTSER, with the aim of 1) providing a synthesis of some of the most emblematic cases of long-term socio-ecological research in Chile; 2) demonstrating the value of these efforts for the integration of research, education and ...

Description: This article discusses a computational study of polarizabilities and second hyperpolarizabilities of inorganic transition metal thiometalates and metalates in solution. Abstract: A systematic study of nonlinear optical (NLO) properties of inorganic transition metal (TM) thiometalates and metalates is reported. Polarizabilities (α) and second hyperpolarizabilities (y) are calculated in solution within the polarizable continuum model. It is found that NLO properties of anionic inorganic complexes can be successfully modeled in solution, when this cannot be done so in the gas phase. Solvent effects are found to significantly increase α and y. The effects are stronger on y (up to 80%) than on α (up to 40%) and stronger on TM thiometalates than on metalates. For α, solvent effects are found to be more important than electron correlation effects. For y, the two effects are similarly important. Solvent effects on α and y caused by subordinate factors other than the dominant electrostatic solute-solvent interactions were studied and assessed to be negligible. Upon solvation, large TM and ligand modification effects on α and y are found. One oxo-to-sulfido substitution results in an increase in α by 38 au and y by 10 000 au.

Description: This article offers comment by the author on the Patagonian Archipelago as the Final Frontier, as written about in a book by Matthew B. Martinic titled, 'Patagonia Archipelago. The Final Frontier.

Description: This article discusses correlation function and generalized master equation of arbitrary age. Abstract: We study a two-state statistical process with a non-Poisson distribution of sojourn times. In accordance with earlier work, we find that this process is characterized by aging and we study three different ways to define the correlation function of arbitrary age of the corresponding dichotomous fluctuation. These three methods yield exact expressions, thus coinciding with the recent result by Godrèche and Luck [J. Stat. Phys. 104, 489 (2001)]. Actually, non-Poisson statistics yields infinite memory at the probability level, thereby breaking any form of Markovian approximation, including the one adopted herein, to find an approximated analytical formula. For this reason, we check the accuracy of this approximated formula by comparing it with the numerical treatment of the second of the three exact expressions. We find that, although not exact, a simple analytical expression for the correlation function of arbitrary age is very accurate. We establish a connection between the correlation function and a generalized master equation of the same age. Thus this formalism, related to models used in glassy materials, allows us to illustrate an approach to the statistical treatment of blinking quantum dots, bypassing the limitations fo ...