204 research outputs found
The Minimal Length and Large Extra Dimensions
Planck scale physics represents a future challenge, located between particle
physics and general relativity. The Planck scale marks a threshold beyond which
the old description of spacetime breaks down and conceptually new phenomena
must appear. Little is known about the fundamental theory valid at Planckian
energies, except that it necessarily seems to imply the occurrence of a minimal
length scale, providing a natural ultraviolet cutoff and a limit to the
possible resolution of spacetime.
Motivated by String Theory, the models of large extra dimensions lower the
Planck scale to values soon accessible. These models predict a vast number of
quantum gravity effects at the lowered Planck scale, among them the production
of TeV-mass black holes and gravitons. Within the extra dimensional scenario,
also the minimal length comes into the reach of experiment and sets a
fundamental limit to short distance physics.
We review the status of Planck scale physics in these effective models.Comment: 18 pages, 5 figures, brief review to appear in Mod. Phys. Let.
Variante morfológica de adultos hembras de Anopheles benarrochi (Diptera: Culicidae) en Putumayo, Colombia
A survey of Anopheles mosquitoes was undertaken in Putumayo, southern Colombia, to clarify the identity of specimens classified as Anopheles (N) evansae in the region. Female anophelines were captured on human bait; then blood fed on small mammals to obtain eggs for progeny broods. Morphological characteristics of the eggs. larvae, pupae and adults of both sexes, including male genitalia were examined. Eggs were obtained from 247 females provisionally identified as A. (N.) evansae Morphology of associated life stages of the progeny broods was compared among 27 families. The morphology of al1 stages corresponded to the published descriptions of Anopheles (N.) benarrochi. However, morphologically variable adult females were noted. In hind tarsomere 2, the dark portion ranged from 0.17 to 0.33 of the tarsomere length; this is less than previously reported for A. (N) benarrochi and overlaps the ranges described for A. (N,) oswaldoi and A. (N) evansae This variable character probably has led to incorrect identifications of adult A. (N.) benarrochifemales as A. (N.) evansae or A. (N.) oswaldoi in specimens from southern Colombia. As a consequence, A. (N) benarrochi has not been previously recognized in Putumayo, and probably has been misidentified in other areas of northwestern South America.Con el propósito de ampliar el conocimiento sobre las especies de Anopheles presentes en el Putumayo, sur de Colombia, y para esclarecer la identidad de los ejemplares clasificados como Anopheles (Nyssorhynchus) evansae en esta región, se recolectaron mosquitos hembra en cebo humano, se alimentaron en pequeños mamíferos y se mantuvieron vivos para la cría de isofamilias. Se realizaron observaciones de las características morfológicas de los huevos, larvas, pupas y adultos de ambos sexos, incluidas las genitalias masculinas. Se obtuvieron 247 posturas de madres identificadas preliminarmente como A. (N) evansae A 27 de estas familias se les estudió la morfología de los estadios asociados. Todos los especimenes fueron subsecuentemente identificados como Anopheles (N) benarrochi por la morfología de los huevos, larvas, pupas y genitalias masculinas, lo cual coincidió con las descripciones publicadas para esta especie. Sin embargo, los adultos hembra de Putumayo presentaron la proporción oscura en el tarsómero posterior 2, entre 0.17 y 0.33 de su longitud, inferior a lo informado para esta especie, lo cual se superpone con los rangos de Anopheles (N.) oswaldoi y A. (N.) evansae. Como resultado de la superposición en este carácter, es probable que hembras adultas de A. (N.) benarrochi hayan sido incorrectamente identificadas como A. (N) evansae y A. (N.) oswaldoi en el sur de Colombia. La presencia de esta variante morfológica ha dificultado la identificación de A. (N.) benarrochi en Putumayo y, probablemente, en otras regiones de Colombia y paises vecinos
Mini Black Holes in the first year of the LHC
The experimental signatures of TeV-mass black hole (BH) formation in heavy
ion collisions at the LHC is examined. We find that the black hole production
results in a complete disappearance of all very high ({} GeV)
back-to-back correlated di-jets of total mass {}TeV. We show
that the subsequent Hawking-decay produces multiple hard mono-jets and discuss
their detection. We study the possibility of cold black hole remnant (BHR)
formation of mass and the experimental distinguishability of
scenarios with BHRs and those with complete black hole decay. Due to the rather
moderate luminosity in the first year of LHC running the least chance for the
observation of BHs or BHRs at this early stage will be by ionizing tracks in
the ALICE TPC. Finally we point out that stable BHRs would be interesting
candidates for energy production by conversion of mass to Hawking radiation.Comment: 10 pages, 2 figure
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Distribution of mosquitoes in the South East of Argentina and first report on the analysis based on 18S rDNA and COI sequences
Although Mar del Plata is the most important city on the Atlantic coast of Argentina, mosquitoes inhabiting such area are almost uncharacterized. To increase our knowledge in their distribution, we sampled specimens of natural populations. After the morphological identification based on taxonomic keys, sequences of DNA from small ribosomal subunit (18S rDNA) and cytochrome c oxidase I (COI) genes were obtained from native species and the phylogenetic analysis of these sequences were done. Fourteen species from the genera Uranotaenia, Culex, Ochlerotatus and Psorophora were found and identified. Our 18S rDNA and COI-based analysis indicates the relationships among groups at the supra-species level in concordance with mosquito taxonomy. The introduction and spread of vectors and diseases carried by them are not known in Mar del Plata, but some of the species found in this study were reported as pathogen vectors
The insecticide resistance status of malaria vectors in the Mekong region
<p>Abstract</p> <p>Background</p> <p>Knowledge on insecticide resistance in target species is a basic requirement to guide insecticide use in malaria control programmes. Malaria transmission in the Mekong region is mainly concentrated in forested areas along the country borders, so that decisions on insecticide use should ideally be made at regional level. Consequently, cross-country monitoring of insecticide resistance is indispensable to acquire comparable baseline data on insecticide resistance.</p> <p>Methods</p> <p>A network for the monitoring of insecticide resistance, MALVECASIA, was set up in the Mekong region in order to assess the insecticide resistance status of the major malaria vectors in Cambodia, Laos, Thailand, and Vietnam. From 2003 till 2005, bioassays were performed on adult mosquitoes using the standard WHO susceptibility test with diagnostic concentrations of permethrin 0.75% and DDT 4%. Additional tests were done with pyrethroid insecticides applied by the different national malaria control programmes.</p> <p>Results</p> <p><it>Anopheles dirus s.s</it>., the main vector in forested malaria foci, was susceptible to permethrin. However, in central Vietnam, it showed possible resistance to type II pyrethroids. In the Mekong delta, <it>Anopheles epiroticus </it>was highly resistant to all pyrethroid insecticides tested. It was susceptible to DDT, except near Ho Chi Minh City where it showed possible DDT resistance. In Vietnam, pyrethroid susceptible and tolerant <it>Anopheles minimus s.l</it>. populations were found, whereas <it>An. minimus s.l</it>. from Cambodia, Laos and Thailand were susceptible. Only two <it>An. minimus s.l</it>. populations showed DDT tolerance. <it>Anopheles vagus </it>was found resistant to DDT and to several pyrethroids in Vietnam and Cambodia.</p> <p>Conclusion</p> <p>This is the first large scale, cross-country survey of insecticide resistance in <it>Anopheles </it>species in the Mekong Region. A unique baseline data on insecticide resistance for the Mekong region is now available, which enables the follow-up of trends in susceptibility status in the region and which will serve as the basis for further resistance management. Large differences in insecticide resistance status were observed among species and countries. In Vietnam, insecticide resistance was mainly observed in low or transmission-free areas, hence an immediate change of malaria vector control strategy is not required. Though, resistance management is important because the risk of migration of mosquitoes carrying resistance genes from non-endemic to endemic areas. Moreover, trends in resistance status should be carefully monitored and the impact of existing vector control tools on resistant populations should be assessed.</p
Developing Global Maps of the Dominant Anopheles Vectors of Human Malaria
Simon Hay and colleagues describe how the Malaria Atlas Project has collated anopheline occurrence data to map the geographic distributions of the dominant mosquito vectors of human malaria
Discovery of a single male Aedes aegypti (L.) in Merseyside, England
© The Author(s). 2017. This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated. The file attached is the published (publishers PDF) version of the article
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