365 research outputs found
Estudio de la Flora Vascular de Ilundáin (Navarra).
En este trabajo hemos realizado un estudio de la Flora Vascular presente en
Ilundáin (Navarra) en una superficie aproximada de 1.35 km2. Para ello se han
recolectado los ejemplares presentes en la zona durante un periodo de tres años (de
1998 a 2001) mediante la realización de herborizaciones de los distintos ambientes,
diferenciados por la vegetación dominante de cada uno (robledal, hayedo, pinar,
matorral,...) y en las distintas estaciones del año.
Así se han recolectado 730 ejemplares pertenecientes a 294 taxones diferentes.
Se ha creado un Catálogo Florístico de la zona bajo estudio donde cada taxon está
acompañado por información referente a la nomenclatura (sinónimos y nombres
vulgares), información biogeográfica (tipo corológico) e información ecológicofuncional
(hábitats o ambientes en los que aparece, especies acompañantes,
fenología, tipo biológico,...) así como todas las citas tomadas de cada uno de ellos
Comet assay to measure DNA repair: approach and applications
Cellular repair enzymes remove virtually all DNA damage before it is fixed; repair therefore plays a crucial role in preventing cancer. Repair studied at the level of transcription correlates poorly with enzyme activity, and so assays of phenotype are needed. In a biochemical approach, substrate nucleoids containing specific DNA lesions are incubated with cell extract; repair enzymes in the extract induce breaks at damage sites and the breaks are measured with the comet assay. The nature of the substrate lesions defines the repair pathway to be studied. This in vitro DNA repair assay has been modified for use in animal tissues, specifically to study the effects of aging and nutritional intervention on repair. Recently, the assay was applied to different strains of Drosophila melanogaster proficient and deficient in DNA repair. Most applications of the repair assay have been in human biomonitoring. Individual DNA repair activity may be a marker of cancer susceptibility; alternatively, high repair activity may result from induction of repair enzymes by exposure to DNA-damaging agents. Studies to date have examined effects of environment, nutrition, lifestyle and occupation, in addition to clinical investigations
In vitro and in vivo anti-Trypanosoma cruzi activity of new arylamine Mannich base-type derivatives
Chagas disease is a neglected tropical disease with 6-7 million people infected worldwide and there is no effective treatment. Therefore, there is an urgent need to continue researching in order to discover novel therapeutic alternatives. We present a series of arylaminoketone derivatives as means of identifying new drugs to treat Chagas disease in the acute phase with greater activity, less toxicity and with a larger spectrum of action than that corresponding to the reference drug benznidazole. Indexes of high selectivity found in vitro formed the basis for later in vivo assays in BALB/c mice. Murine model results show that compounds 3, 4, 7 and 10 induced a remarkable decrease in parasitemia levels in acute phase and the parasitemia reactivation following immunosuppression, and curative rates were higher than with benznidazole. These high anti-parasitic activities encourage us to propose these compounds as promising molecules for developing an easy to synthesize anti-Chagas agent
Clean Development Mechanism Projects in Latin America : beyond reducing CO2 (e) emissions. A case study in Chile
The Clean Development Mechanism (CDM) was created to compensate
underdeveloped countries for their contribution to mitigate climate change. Under
these rules, those projects showing the lower cost, in terms of investment, for each
tonne of CO2 (e) saved, will be the ones selected. However, even if this selection
process seems quite rational, it can result in a suboptimal allocation of resources,
when other impacts of these projects, also having to do with social welfare, are
considered. This point is illustrated in this paper by comparing the financial cost of CER
credits of two current CDM projects in Chile, the Santa Marta Landfill Gas Capture
Project and the Corneche‐Los Guindos Methane Capture from Swine Manure Project,
with that of a third, “virtual” project, the upgrading of the Renca Generation Plant in
Santiago de Chile to a gas fired combined cycle (CCGT) Plant. Even if this third project is
much less efficient in financial terms, it shows a very important ancillary benefit: its
impact on human health. When this impact is introduced, the result, as expected, is a
drastic change in the relative social profitability of the three projects
Clean Development Mechanism Projects in Latin America : beyond reducing CO2 (e) emissions. A case study in Chile
The Clean Development Mechanism (CDM) was created to compensate
underdeveloped countries for their contribution to mitigate climate change. Under
these rules, those projects showing the lower cost, in terms of investment, for each
tonne of CO2 (e) saved, will be the ones selected. However, even if this selection
process seems quite rational, it can result in a suboptimal allocation of resources,
when other impacts of these projects, also having to do with social welfare, are
considered. This point is illustrated in this paper by comparing the financial cost of CER
credits of two current CDM projects in Chile, the Santa Marta Landfill Gas Capture
Project and the Corneche‐Los Guindos Methane Capture from Swine Manure Project,
with that of a third, “virtual” project, the upgrading of the Renca Generation Plant in
Santiago de Chile to a gas fired combined cycle (CCGT) Plant. Even if this third project is
much less efficient in financial terms, it shows a very important ancillary benefit: its
impact on human health. When this impact is introduced, the result, as expected, is a
drastic change in the relative social profitability of the three projects
Assessing the carcinogenic potential of low-dose exposures to chemical mixtures in the environment: the challenge ahead.
Lifestyle factors are responsible for a considerable portion of cancer incidence worldwide, but credible estimates from the World Health Organization and the International Agency for Research on Cancer (IARC) suggest that the fraction of cancers attributable to toxic environmental exposures is between 7% and 19%. To explore the hypothesis that low-dose exposures to mixtures of chemicals in the environment may be combining to contribute to environmental carcinogenesis, we reviewed 11 hallmark phenotypes of cancer, multiple priority target sites for disruption in each area and prototypical chemical disruptors for all targets, this included dose-response characterizations, evidence of low-dose effects and cross-hallmark effects for all targets and chemicals. In total, 85 examples of chemicals were reviewed for actions on key pathways/mechanisms related to carcinogenesis. Only 15% (13/85) were found to have evidence of a dose-response threshold, whereas 59% (50/85) exerted low-dose effects. No dose-response information was found for the remaining 26% (22/85). Our analysis suggests that the cumulative effects of individual (non-carcinogenic) chemicals acting on different pathways, and a variety of related systems, organs, tissues and cells could plausibly conspire to produce carcinogenic synergies. Additional basic research on carcinogenesis and research focused on low-dose effects of chemical mixtures needs to be rigorously pursued before the merits of this hypothesis can be further advanced. However, the structure of the World Health Organization International Programme on Chemical Safety 'Mode of Action' framework should be revisited as it has inherent weaknesses that are not fully aligned with our current understanding of cancer biology
Self-synchronized Encryption for Physical Layer in 10Gbps Optical Links
In this work a new self-synchronized encryption method for 10 Gigabit optical links is proposed and developed. Necessary modifications to introduce this kind of encryption in physical layers based on 64b/66b encoding, such as 10GBase-R, have been considered. The proposed scheme encrypts directly the 64b/66b blocks by using a symmetric stream cipher based on an FPE (Format Preserving Encryption) block cipher operating in PSCFB (Pipelined Statistical Cipher Feedback) mode. One of the main novelties in this paper is the security analysis done for this mode. For the first time, an expression for the IND-CPA (Indistinguishability under Chosen-Plaintext Attack) advantage of any adversary over this scheme has been derived. Moreover, it has been concluded that this mode can be considered secure in the same way of traditional modes are. In addition, the overall system has been simulated and implemented in an FPGA (Field Programmable Gate Array). An encrypted optical link has been tested with Ethernet data frames, concluding that it is possible to cipher traffic at this level, getting maximum throughput and hiding traffic pattern from passive eavesdroppers
Physical Layer Encryption for Industrial Ethernet in Gigabit Optical Links
Industrial Ethernet is a technology widely spread in factory floors and critical infrastructures where a high amount of data need to be collected and transported. Fiber optic networks at gigabit rates fit well with that type of environment, where speed, system performance, and reliability are critical. In this paper, a new encryption method for high-speed optical communications suitable for such kinds of networks is proposed. This new encryption method consists of a symmetric streaming encryption of the 8b/10b data flow at physical coding sublayer level. It is carried out thanks to a format preserving encryption block cipher working in CTR (counter) mode. The overall system has been simulated and implemented in a field programmable gate array. Thanks to experimental results, it can be concluded that it is possible to cipher traffic at this physical level in a secure way. In addition, no overhead is introduced during encryption, getting minimum latency and maximum throughput
Chaotic Encryption Applied to Optical Ethernet in Industrial Control Systems
In the past decades, Ethernet has become an alternative technology for the field buses traditionally used in industrial control systems and distributed measurement systems. Among different transmission media in Ethernet standards, optical fiber provides the best bandwidth, excellent immunity to electromagnetic interference, and less signal loses than other wired media. Due to the absence of a standard that provides security at the physical layer of optical Ethernet links, the main motivation of this paper is to propose and implement the necessary modifications to introduce encryption in Ethernet 1000Base-X standard. This has consisted of symmetric streaming encryption of the 8b10b symbols flow at physical coding sublayer level, thanks to a keystream generator based on chaotic algorithm. The overall system has been implemented and tested in an field programmable gate array and Ethernet traffic has been encrypted and transmitted over an optical link. The experimental results show that it is possible to cipher traffic at this level and hide the complete Ethernet traffic pattern from passive eavesdroppers. In addition, no space overhead is introduced in data frames during encryption, achieving the maximum throughput
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