Rare or poorly known scorpions from Colombia. II. Redescription of \u3cem\u3eTityus columbianus\u3c/em\u3e (Thorell, 1876) (Scorpiones: Buthidae)

A fully illustrated redescription is herein presented of Tityus columbianus (Thorell, 1876). It includes a description of the adult male, an update of its geographical distribution, and detailed information about age-related individual variation, with comments on the taxonomy of the “Tityus clathratus” group

Rare or poorly known scorpions from Colombia. I. Redescription of \u3cem\u3eTityus macrochirus\u3c/em\u3e Pocock, 1897 (Scorpiones: Buthidae)

A fully illustrated redescription is herein presented of Tityus macrochirus Pocock, 1897, based upon a series of specimens of both sexes recently collected in a new location near the type locality. We include an update of its geographical distribution and detailed information about age-related individual variation

Non-linear response of single-molecule magnets: field-tuned quantum-to-classical crossovers

Quantum nanomagnets can show a field dependence of the relaxation time very different from their classical counterparts, due to resonant tunneling via excited states (near the anisotropy barrier top). The relaxation time then shows minima at the resonant fields H_{n}=n D at which the levels at both sides of the barrier become degenerate (D is the anisotropy constant). We showed that in Mn12, near zero field, this yields a contribution to the nonlinear susceptibility that makes it qualitatively different from the classical curves [Phys. Rev. B 72, 224433 (2005)]. Here we extend the experimental study to finite dc fields showing how the bias can trigger the system to display those quantum nonlinear responses, near the resonant fields, while recovering an classical-like behaviour for fields between them. The analysis of the experiments is done with heuristic expressions derived from simple balance equations and calculations with a Pauli-type quantum master equation.Comment: 4 pages, 3 figures. Submitted to Phys. Rev. B, brief report

A search for diffuse bands in fullerene planetary nebulae: evidence of diffuse circumstellar bands

Large fullerenes and fullerene-based molecules have been proposed as carriers of diffuse interstellar bands (DIBs). The recent detection of the most common fullerenes (C60 and C70) around some planetary nebulae (PNe) now enable us to study the DIBs towards fullerene-rich space environments. We search DIBs in the optical spectra towards three fullerene-containing PNe (Tc 1, M 1-20, and IC 418). Special attention is given to DIBs which are found to be unusually intense towards these fullerene sources. In particular, an unusually strong 4428A absorption feature is a common charateristic of fullerene PNe. Similar to Tc 1, the strongest optical bands of neutral C60 are not detected towards IC 418. Our high-quality (S/N > 300) spectra for PN Tc 1, together with its large radial velocity, permit us to search for the presence of diffuse bands of circumstellar origin, which we refer to as diffuse circumstellar bands (DCBs). We report the first tentative detection of two DCBs at 4428 and 5780 A in the fullerene-rich circumstellar environment around the PN Tc 1. Laboratory and theoretical studies of fullerenes in their multifarious manifestations (carbon onions, fullerene clusters, or even complex species formed by fullerenes and other molecules like PAHs or metals) may help solve the mystery of some of the diffuse band carriers.Comment: Accepted for publication in Astronomy & Astrophysics (16 pages, 10 figures, and 7 Tables); final version (changes regarding PN M 1-20 and language corrected

Adapting cause and effects methodology to your Safety instrumented system (SIS) to reduce human errors from engineering, operations and beyond

PresentationA safety instrumented system (SIS) is used to implement one or more Safety Instrumented Functions (SIFs) which are designed to reduce the likelihood of hazardous risk by decreasing the frequency of unwanted events (accidents). The amount of risk reduction that an SIS can provide is represented by its safety integrity level (SIL). The SIS is designed to detect when the process reaches a hazardous condition and respond accordingly to move the process to a safe state, thus preventing the unwanted accident from occurring. Studies indicate however, that over 50% of all SIS failures are related Systematic faults introduced by human error. While many SIS systems boast having SIL 3 certification, it’s often the human interactions that render many of these well intended systems to be essentially idle. A cause and effects methodology is an approach many in the industry are exploring to help reduce human errors throughout the entire safety lifecycle of the SIS

Regional Convergence in Latin America: 1980-2000

The objective of the work is to determine the existence of convergence (absolute and conditional) for the region of Latin America and to determine the main variables that affect the economic growth of these countries. The main results are the following ones: there is empirical evidence of absolute and conditional convergence in the period from study to a rate very similar to found by other studies for other groups of countries or regions of the interior of a same country (around the 2 percent).Convergencia; crecimiento economico; capital humano; America Latina; Latinoamerica

IMPROVING INDUSTRIAL PERFOMANCE OF Chlamydomonas reinhardtii THROUGH GENETIC ENGINEERING: A FOCUS ON STRESS TOLERANCE AND IRON TRANSPORT

Algal cultures exhibit the potential as robust systems for pharmaceutical production, as sustainable sources of nutrition both for humans and livestock, and as renewable biomass feedstock for biofuel production. Algal biomass grows quickly, requires minimal nutrient supplementation and sunlight, and has the ability to sequester environmental CO2. Although these properties seem attractive, algal industrial cultivation is still far from optimal; leading to non-ideal culture conditions which induce cellular stress that cause a loss in productivity. Furthermore, bioprocessing of algal biomass for biofuel production is still in its infancy and encounters many obstacles and bottlenecks after mass cultivation, mainly cell separation from culture. In this study we aim to address these industrial issues by employing the power of genetic and metabolic engineering. Specifically, we employ a two-fold plan to increase the stress tolerance and intracellular iron concentration of model organism, Chlamydomonas reinhardtii, by overexpressing mammalian anti-apoptotic BCL-XL protein and the native membrane coupled iron transporter IRT2. In order to achieve our goal a gene construct driven the native hsp70/rbcS2 tandem promoter was constructed containing the appropriate gene of interest and carrying a Hygromycin B resistance marker for downstream selection. After transformation, resulting colonies were screened via colony PCR; positive colonies were subcultured and exposed to a variety apoptosis inducing agents tailored to mimic stresses involved with industrial cultivation; mainly photooxidative damage, exposure to reactive oxygen species, osmotic pressure change, and intracellular damage caused by high irradiance. While the transgenic cell line experienced a reduced growth rate, it reached a higher cell density and featured higher cell longevity in comparison to the wild type after prolonged culture. Furthermore, in all stress related experiments the transgenic cell line outperformed the wild type, often with stark phenotypic changes. Moreover, RT-PCR analysis confirmed RNA level expression of this peptide allowing us to conclude that the transgenic cell line was producing a functional form of this recombinant anti-apoptotic protein leading to more robust stress tolerance