1,186 research outputs found
Effects of Orientations, Aspect Ratios, Pavement Materials and Vegetation Elements on Thermal Stress inside Typical Urban Canyons
The analysis of local climate conditions to test artificial urban boundaries and related climate hazards through modelling tools should become a common practice to inform public authorities about the benefits of planning alternatives. Different finishing materials and sheltering objects within urban canyons (UCs) can be tested, predicted and compared through quantitative and qualitative understanding of the relationships between the microclimatic environment and subjective thermal assessment. This process can work as support planning instrument in the early design phases as has been done in this study that aims to analyze the thermal stress within typical UCs of Bilbao (Spain) in summertime through the evaluation of Physiologically Equivalent Temperature using ENVI-met. The UCs are characterized by different orientations, height-to-width aspect ratios, pavement materials, trees’ dimensions and planting pattern. Firstly, the current situation was analyzed; secondly, the effects of asphalt and red brick stones as streets’ pavement materials were compared; thirdly, the benefits of vegetation elements were tested. The analysis demonstrated that orientation and aspect ratio strongly affect the magnitude and duration of the thermal peaks at pedestrian level; while the vegetation elements improve the thermal comfort up to two thermophysiological assessment classes. The outcomes of this study, were transferred and visualized into green planning recommendations for new and consolidated urban areas in Bilbao.The work leading to these results has received funding from COST Action TU0902, the European Community’s Seventh Framework Programme under Grant Agreement No. 308497, Project RAMSES—Reconciling Adaptation, Mitigation and Sustainable Development for Cities (2012–2017) and Diputación Foral de Bizkaia Exp. 6-12-TK-2010-0027, Project SICURB-ITS- Desarrollo de Sistemas para el análisis de la Contaminación atmosférica en zonas URBanas integrados en ITS (2010–2011)
Length-weight relationships of demersal fishes from the upper continental slope off Colombia
Parameters of the length–weight relationship of the form W=aLb are presented for 45 demersal fish species caught on the upper continental slope of the Caribbean Sea off Colombia. The b values varied between 2.13 and 4.97, with the mean b = 3.042 (95% CI, 2.887- 3.196)
X- and gamma-ray studies of HESS J1731-347 coincident with a newly discovered SNR
In the survey of the Galactic plane conducted with H.E.S.S., many VHE
gamma-ray sources were discovered for which no clear counterpart at other
wavelengths could be identified. HESS J1731-347 initially belonged to this
source class. Recently however, the new shell-type supernova remnant (SNR)
G353.6-0.7 was discovered in radio data, positionally coinciding with the VHE
source. We will present new X-ray observations that cover a fraction of the VHE
source, revealing nonthermal emission that most likely can be interpreted as
synchrotron emission from high-energy electrons. This, along with a larger
H.E.S.S. data set which comprises more than twice the observation time used in
the discovery paper, allows us to test whether the VHE source may indeed be
attributed to shell-type emission from that new SNR. If true, this would make
HESS J1731-347 a new object in the small but growing class of non-thermal
shell-type supernova remnants with VHE emission.Comment: 4 pages, 5 figures, to appear in proceedings of the 31st ICRC, Lodz,
Polan
XMM-Newton evidence of shocked ISM in SN 1006: indications of hadronic acceleration
Shock fronts in young supernova remnants are the best candidates for being
sites of cosmic ray acceleration up to a few PeV, though conclusive
experimental evidence is still lacking. Hadron acceleration is expected to
increase the shock compression ratio, providing higher postshock densities, but
X-ray emission from shocked ambient medium has not firmly been detected yet in
remnants where particle acceleration is at work. We exploited the deep
observations of the XMM-Newton Large Program on SN 1006 to verify this
prediction. We performed spatially resolved spectral analysis of a set of
regions covering the southeastern rim of SN 1006. We studied the spatial
distribution of the thermodynamic properties of the ambient medium and
carefully verified the robustness of the result with respect to the analysis
method. We detected the contribution of the shocked ambient medium. We also
found that the postshock density of the interstellar medium significantly
increases in regions where particle acceleration is efficient. Under the
assumption of uniform preshock density, we found that the shock compression
ratio reaches a value of ~6 in regions near the nonthermal limbs. Our results
support the predictions of shock modification theory and indicate that effects
of acceleration of cosmic ray hadrons on the postshock plasma can be observed
in supernova remnants.Comment: Accepted for publication in A&
Lucilia sericata strain from Colombia: Experimental Colonization, Life Tables and Evaluation of Two Artifcial Diets of the Blowfy Lucilia sericata (Meigen) (Diptera: Calliphoridae), Bogotá, Colombia Strain
The objective of this work was to establish, under experimental laboratory conditions, a colony of Lucilia sericata, Bogotá-Colombia strain, to build life tables and evaluate two artifcial diets. This blowfy is frequently used in postmortem interval studies and in injury treatment. The parental adult insects collected in Bogotá were maintained in cages at 22°C±1 average temperature, 60%±5 relative humidity and 12 h photoperiodicity. The blowfies were fed on two artifcial diets that were evaluated over seven continuous generations. Reproductive and population parameters were assessed. The life cycle of the species was expressed in the number of days of the different stages: egg = 0.8±0.1, larvae I = 1.1±0.02, larvae II = 1.94±0.16, larvae III = 3.5±0.54, pupae = 6.55±0.47, male adult = 28.7±0.83 and female adult = 33.5±1.0. Total survival from egg stage to adult stage was 91.2% for diet 1, while for diet 2 this parameter was 40.5%. The lifetime reproductive output was 184.51±11.2 eggs per female. The population parameters, as well as the reproductive output of the blowfies that were assessed, showed relatively high values, giving evidence of the continuous increase of the strain over the different generations and making possible its maintenance as a stable colony that has lasted for more than two years
Constraining blazar distances with combined Fermi and TeV data: an empirical approach
We discuss a method to constrain the distance of blazars with unknown
redshift using combined observations in the GeV and TeV regimes. We assume that
the VHE spectrum corrected for the absorption through the interaction with the
Extragalactic Background Light can not be harder than the spectrum in the
Fermi/LAT band. Starting from the observed VHE spectral data we derive the
EBL-corrected spectra as a function of the redshift z and fit them with power
laws to be compared with power law fits to the LAT data. We apply the method to
all TeV blazars detected by LAT with known distance and derive an empirical law
describing the relation between the upper limits and the true redshifts that
can be used to estimate the distance of unknown redshift blazars. Using
different EBL models leads to systematic changes in the derived upper limits.
Finally, we use this relation to infer the distance of the unknown redshift
blazar PKS 1424+240.Comment: 5 pages, 4 figures, accepted for publication in MNRAS, minor revisio
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