The Venezuelan Institute for Scientific Research , or Instituto Venezolano de Investigaciones Cientificas, is a scientific research institute and graduate training center in Venezuela founded by government decree on February 9, 1959. It has its origins in the Venezuelan Institute of Neurology and Brain Research , which Humberto Fernandez Moran founded in 1955.The center has the Marcel Roche Library, recognized in 1996 by UNESCO as being "the best Regional Library for Science and Technology".The headquarters of the IVIC is located near San Antonio de los Altos, in Altos de Pipe, Miranda State. The grounds cover 832-acre headquarters, where are the scientific and academic facilities, residences for researchers, students and staff, storeroom, dining, administration and service area, library, etc. Within this area there are some pockets of tropical cloud forest and a couple of streams. IVIC is currently in the process of regionalization, of which there have been two sub-regional headquarters in Mérida and Zulia states.Also have a Scientific Research Station near Higuerote, Miranda State. Wikipedia.
News Article | April 17, 2017
IMAGE: Bare peat surfaces in the discontinuous permafrost zone of the sub-Arctic East European tundra. New research explores the source of unexpectedly high nitrous oxide emissions from such bare peat soils... view more A new study from the University of Eastern Finland presents, for the first time, the isotopic fingerprint of nitrous oxide produced by Arctic soils. The finding opens new avenues for predicting future trends in atmospheric nitrous oxide as well as in identifying climate change mitigation actions in the Arctic, a region that is particularly sensitive to climate change. Nitrous oxide (N2O) is a powerful greenhouse gas and also the second largest contributor to ozone depletion in the stratosphere. It is produced naturally by soils, with agricultural and tropical rain forest soils being the main sources of N2O to the atmosphere. Until recently, scientists assumed that nitrous oxide emissions were negligible in colder climate regions like the Arctic and sub-Arctic. This assumption, however, was contradicted by scientists from the University of Eastern Finland a decade ago, when they discovered that bare peat surfaces in permafrost peatlands are releasing high amounts of N2O, despite the general nitrogen limitation of tundra ecosystems. Since then, N2O emissions and their underlying processes have been the object of plenty of research and, also, debate. In a new study, researchers from the University of Eastern Finland, together with colleagues from the Venezuelan Institute for Scientific Research (IVIC) and the University of California, Berkeley, explore the isotopic composition and potential sources of nitrous oxide emitted by soils in the sub-Arctic tundra. The study explores new frontiers in polar science, and the approach used establishes a legacy of data and methodologies that have the potential to link the Arctic ecosystem with the global N2O cycle. In the study, the researchers examined nitrogen and oxygen isotopes in N2O samples collected from permafrost peatland sites in northwestern Russia. Using "site preference" analysis, the scientists also identified the specific isotopes occupying the two different nitrogen sites within the nitrous oxide molecule. The study presents for the first time the isotopic fingerprint of N2O produced by soils of Arctic tundra, thereby contributing to an understanding of N2O production mechanisms in this understudied environment. Since different microbial processes leave distinct isotopic fingerprints on nitrous oxide, the researchers also hoped to figure out the relative amounts of nitrous oxide emitted by different nitrogen-processing microbes in the tundra soils. The results suggest that the N2O emissions from bare tundra peat soils might be due to nitrifier denitrification, a microbial process that transforms ammonia (NH4) into N2 in a series of steps, one of which produces nitrous oxide. However, in the study year N2O emissions were low compared to previous years, and the reasons for the high emissions are still unclear. The isotope data was not conclusive enough, and even the sophisticated site preference technique did not provide enough information to tease out the relative roles of different microbes. Nonetheless, the findings are valuable because isotopic nitrous oxide data from the Arctic and sub-Arctic are extremely rare. The findings could aid predictions of future trends in atmospheric nitrous oxide and help to identify mitigation actions in the Arctic, a region that is particularly sensitive to climate change. In the future, enhanced N2O emissions from natural soil such as sub-Arctic tundra might mask the isotope effect caused by mitigation actions derived from agriculture. The findings were reported in Global Biogeochemical Cycles, and the article is featured as a Research Spotlight in the Eos magazine at https:/ Gil, J., T. Pérez, K. Boering, P. J. Martikainen, and C. Biasi (2017), Mechanisms responsible for high N2O emissions from subarctic permafrost peatlands studied via stable isotope techniques, Global Biogeochem. Cycles, 31, 172-189, doi:10.1002/2015GB005370.
San-Blas E.,Venezuelan Institute for Scientific Research
Biological Control | Year: 2013
Entomopathogenic nematodes have achieved a place in biological control programmes because of their effectiveness, speed of action, innocuousness to non-insect targets and simplicity of mass production. However many challenges derived due to the lack of knowledge in some critical steps from laboratories to their use in the fields, have to be resolved in order to improve their performance and to reduce the mass production costs. For those reasons, studies on entomopathogenic nematology have increased considerably in the last few decades. Also, there have been important changes in the ways that results are published; many of them relate to major transformations in scientific trends. Using bibliometric tools we characterize variations in number, types of journal, countries of origin, research topics and the number of participating countries, of 1923 papers (from 1980 to 2010) reported in several on-line editorial databases. © 2013 Elsevier Inc.
Zent E.L.,Venezuelan Institute for Scientific Research
Environmental Research Letters | Year: 2013
The current environmental crisis permeates the discourse and concerns of people all over the world. Consideration of diverse environmental ethics showing the alternative ways in which people conceptualize and relate to nature and natural resources are critical for bringing about more sustainable human behaviors. After a brief review of Western historical notions of nature, this work explores the ecogony, or causal reasons, that trigger the behavior of the Jotï, an Amerindian people of the Venezuelan Amazon, with other entities and the forest that they inhabit. The analysis presented synthesizes 15 years of transdisciplinary ethno-ecological research comprising quantitative and qualitative methods (collection of herbarium voucher specimens, floristic inventories in forest plots, structured interviews focused on plot vegetation, semi-structured interviews of life-histories, participant observation, time allocation studies, food resource accounting, focal person following observations, garden crop inventories and censuses, mapping of wild resource harvest locations, among others). Jotï pragmatic and ideological tenets generate a distinctive environmental ethics based on ecogonic nodes. Notions of interdependence, humanity and person are articulated on a daily basis through several dynamics: (1) hyper-awareness of all living things' dependence on each other and other elements of the biophysical environment at macroscales and microscales, (2) the construction of human spiritual, conscious, physical and agentive constituents from a variety of diverse botanical and zoological species and mineral components of their homeland, and (3) an understanding of the aggregate surroundings, including a significant portion of the biotic and abiotic components, as potential subjects with awareness, creativity and moral stances. This condition of interdependence confers rights and duties on all the parts. Jotï horizontal communications with and among life-forms sustain their condition as committed actors in the configuration of the forests that they inhabit. © 2013 IOP Publishing Ltd.
Urbina J.A.,Venezuelan Institute for Scientific Research
Drugs of the Future | Year: 2010
Chagas' disease, caused by the kinetoplastid protozoon Trypanosoma cruzi, remains the highest parasitic disease burden in the American continent and is now spreading to nonendemic countries due to international migrations. Specific therapy for this complex condition remains unsatisfactory due to limited efficacy and common side effects of currently available drugs (nifurtimox and benznidazole), as well as controversies regarding the pathogenesis of the disease in the chronic stage. In contrast to long-held views on the autoimmune origin of the pathological manifestations of the chronic stage of the disease, recent studies have concluded that the persistence of parasites is the key factor leading to the sustained inflammatory responses underlying the characteristic lesions of chronic Chagas' disease, and that this condition should be treated as an infectious and not an autoimmune disease. Among the most promising approaches to new treatments are ergosterol biosynthesis inhibitors, such as posaconazole and ravuconazole, which are poised to enter clinical trials in Chagas' disease in the short term; the antiarrhythmic drug amiodarone, which was recently shown to also have potent activity against T. cruzi; inhibitors of cruzipain, the main cysteine protease of T. cruzi; and combination therapies such as nifurtimox or benznidazole with posaconazole, ravuconazole or amiodarone hydrochloride. Copyright © 2010 Prous Science, S.A.U. or its licensors. All rights reserved.
Takiff H.E.,Venezuelan Institute for Scientific Research |
Feo O.,Venezuelan Institute for Scientific Research
The Lancet Infectious Diseases | Year: 2015
Whole-genome sequencing (WGS) is now common as a result of new technologies that can rapidly sequence a complete bacterial genome for US$500 or less. Many studies have addressed questions about tuberculosis with WGS, and knowing the sequence of the entire genome, rather than only a few fragments, has greatly increased the precision of molecular epidemiology and contact tracing. Additionally, topics such as the mutation rate, drug resistance, the target of new drugs, and the phylogeny and evolution of the Mycobacterium tuberculosis complex bacteria have been elucidated by WGS. Nonetheless, WGS has not explained differences in transmissibility between strains, or why some strains are more virulent than others or more prone to development of multidrug resistance. With advances in technology, WGS of clinical specimens could become routine in high-income countries; however, its relevance will probably depend on easy to use software to efficiently process the sequences produced and accessible genomic databases that can be mined in future studies. © 2015 Elsevier Ltd.
Urbina J.A.,Venezuelan Institute for Scientific Research
Acta Tropica | Year: 2010
A critical review of the development of specific chemotherapeutic approaches for the management of American Trypanosomiasis or Chagas disease is presented, including controversies on the pathogenesis of the disease, the initial efforts that led to the development of currently available drugs (nifurtimox and benznidazole), limitations of these therapies and novel approaches for the development of anti- Trypanosoma cruzi drugs, based on our growing understanding of the biology of this parasite. Among the later, the most promising approaches are ergosterol biosynthesis inhibitors such as posaconazole and ravuconazole, poised to enter clinical trials for chronic Chagas disease in the short term; inhibitors of cruzipain, the main cysteine protease of T. cruzi, essential for its survival and proliferation in vitro and in vivo; bisphosphonates, metabolic stable pyrophosphate analogs that have trypanocidal activity through the inhibition of the parasite's farnesyl-pyrophosphate synthase or hexokinase; inhibitors of trypanothione synthesis and redox metabolism and inhibitors of hypoxanthine-guanine phosphoribosyl-transferase, an essential enzyme for purine salvage in T. cruzi and related organisms.Finally, the economic and political challenges faced by development of drugs for the treatment of neglected tropical diseases, which afflict almost exclusively poor populations in developing countries, are analyzed and recent potential solutions for this conundrum are discussed. © 2009.
Laine J.,Venezuelan Institute for Scientific Research
Renewable and Sustainable Energy Reviews | Year: 2012
The increasing demand of fossil fuels and decreasing light oil proven reserves lead to a future scenario of abundant coke production from the refinement of non-conventional fossil hydrocarbons. This paper highlights the possibility of using coke as an agrichar for preparing fertile soils resembling Amazonian terra preta. It is suggested that this alternative may contribute to both the capture of greenhouse gas by afforestation and the increase of rainfall by the albedo effect. It is proposed that the ideal agrichar must function as a store of nutrients in the form of graphene substituted NPK groups at the micropore molecular structure, providing habitat for plant friendly microorganism inside its macropores. The possibility of a sink effect connecting nutrient storage with microorganisms has also been proposed. A preliminary discussion on the possible coking procedures to improve the resulting agrichar efficacy, three options for large scale desert greening using agrichar as well as recommendations for further research are presented. © 2012 Elsevier Ltd.
Gwirtz J.A.,Kansas State University |
Garcia-Casal M.N.,Venezuelan Institute for Scientific Research
Annals of the New York Academy of Sciences | Year: 2014
Corn is the cereal with the highest production worldwide and is used for human consumption, livestock feed, and fuel. Various food technologies are currently used for processing industrially produced maize flours and corn meals in different parts of the world to obtain precooked refined maize flour, dehydrated nixtamalized flour, fermented maize flours, and other maize products. These products have different intrinsic vitamin and mineral contents, and their processing follows different pathways from raw grain to the consumer final product, which entail changes in nutrient composition. Dry maize mechanical processing creates whole or fractionated products, separated by anatomical features such as bran, germ, and endosperm. Wet maize processing separates by chemical compound classification such as starch and protein. Various industrial processes, including whole grain, dry milling fractionation, and nixtamalization, are described. Vitamin and mineral losses during processing are identified and the nutritional impacts outlined. Also discussed are the vitamin and mineral contents of corn. © 2013.
Escobar W.,Venezuelan Institute for Scientific Research
European journal of pain (London, England) | Year: 2012
The most commonly used drugs against pain act by inhibiting the cyclooxygenases (COXs). Metamizol (dipyrone) inhibits the COXs and is widely used in Europe and Latin America as a non-opioid analgesic. One target of metamizol and other non-opioid analgesics is the periaqueductal grey matter (PAG), where they trigger descending inhibition of spinal nociceptive transmission. Also, cannabinoids exert an analgesic action at several structures in the peripheral and central nervous system, including the PAG. The present study investigates whether the antinociceptive action of metamizol in the lateral-ventrolateral (LVL) PAG during inflammation is related to endocannabinoids. In anaesthetized rats, unitary action potentials were recorded from spinal nociceptive neurons with receptive fields in the ipsilateral hind paw. Inflammation of the paw induced neuronal hyperexcitability, which was attenuated by intra-LVL-PAG microinjection of metamizol either at the beginning of inflammation or when hyperexcitability was fully established. In both cases, the antinociceptive effect of metamizol was reduced by a microinjection of AM251, an antagonist at the CB1 cannabinoid receptor, either into the LVL-PAG or into the rostral ventromedial medulla (RVM). The RVM is a downstream structure that funnels PAG-derived descending inhibition into the spinal cord. These results show that endocannabinoids and their CB1 receptor (1) contribute at the LVL-PAG to the antinociceptive effects of metamizol, and possibly other non-opioid analgesics; and (2) participate in the PAG-derived activation of RVM descending antinociceptive influences. © 2011 European Federation of International Association for the Study of Pain Chapters.
Kryachko E.S.,NASU Bogolyubov Institute for Theoretical Physics |
Ludena E.V.,Venezuelan Institute for Scientific Research |
Ludena E.V.,ESPOL Polytechnic University
Physics Reports | Year: 2014
Guided by the above motto (quotation), we review a broad range of issues lying at the foundations of Density Functional Theory, DFT, a theory which is currently omnipresent in our everyday computational study of atoms and molecules, solids and nano-materials, and which lies at the heart of modern many-body computational technologies. The key goal is to demonstrate that there are definitely the ways to improve DFT. We start by considering DFT in the larger context provided by reduced density matrix theory (RDMT) and natural orbital functional theory (NOFT), and examine the implications that N-representability conditions on the second-order reduced density matrix (2-RDM) have not only on RDMT and NOFT but, also, by extension, on the functionals of DFT. This examination is timely in view of the fact that necessary and sufficient N-representability conditions on the 2-RDM have recently been attained.In the second place, we review some problems appearing in the original formulation of the first Hohenberg-Kohn theorem which is still a subject of some controversy. In this vein we recall Lieb's comment on this proof and the extension to this proof given by Pino etal. (2009), and in this context examine the conditions that must be met in order that the one-to-one correspondence between ground-state densities and external potentials remains valid for finite subspaces (namely, the subspaces where all Kohn-Sham solutions are obtained in practical applications).We also consider the issue of whether the Kohn-Sham equations can be derived from basic principles or whether they are postulated. We examine this problem in relation to ab initio DFT. The possibility of postulating arbitrary Kohn-Sham-type equations, where the effective potential is by definition some arbitrary mixture of local and non-local terms, is discussed.We also deal with the issue of whether there exists a universal functional, or whether one should advocate instead the construction of problem-geared functionals. These problems are discussed by making reference to ab initio DFT as well as to the local-scaling-transformation version of DFT, LS-DFT.In addition, we examine the question of the accuracy of approximate exchange-correlation functionals in the light of their non-observance of the variational principle. Why do approximate functionals yield reasonable (and accurate) descriptions of many molecular and condensed matter properties? Are the conditions imposed on exchange and correlation functionals sufficiently adequate to produce accurate semi-empirical functionals? In this respect, we consider the question of whether the results reflect a true approach to chemical accuracy or are just the outcome of a virtuoso-like performance which cannot be systematically improved. We discuss the issue of the accuracy of the contemporary DFT results by contrasting them to those obtained by the alternative RDMT and NOFT.We discuss the possibility of improving DFT functionals by applying in a systematic way the N-representability conditions on the 2-RDM. In this respect, we emphasize the possibility of constructing 2-matrices in the context of the local scaling transformation version of DFT to which the N-representability condition of RDM theory may be applied.We end up our revision of HKS-DFT by considering some of the problems related to spin symmetry and discuss some current issues dealing with a proper treatment of open-shell systems. We are particularly concerned, as in the rest of this paper, mostly with foundational issues arising in the construction of functionals.We dedicate the whole Section 4 to the local-scaling transformation version of density functional theory, LS-DFT. The reason is that in this theory some of the fundamental problems that appear in HKS-DFT, have been solved. For example, in LS-DFT the functionals are, in principle, designed to fulfill v- and N-representability conditions from the outset. This is possible because LS-DFT is based on density transformation (local-scaling of coordinates proceeds through density transformation) and so, because these functionals are constructed from prototype N-particle wavefunctions, the ensuing density functionals already have built-in N-representability conditions. This theory is presented in great detail with the purpose of illustrating an alternative way to HKS-DFT which could be used to improve the construction of HKS-DFT functionals. Let us clearly indicate, however, that although appealing from a theoretical point of view, the actual application of LS-DFT to large systems has not taken place mostly because of technical difficulties. Thus, our aim in introducing this theory is to foster a better understanding of its foundations with the hope that it may promote a cross-hybridization with the already existing approaches. Also, to complete our previous discussion on symmetry, in particular, spin-symmetry, we discuss this issue from the perspective of LS-DFT.Finally, in Section 6, we discuss dispersion molecular forces emphasizing their relevance to DFT approaches. © 2014 Elsevier B.V.