1,838 research outputs found
On Optimal Detection of Point Sources in CMB Maps
Point-source contamination in high-precision Cosmic Microwave Background
(CMB) maps severely affects the precision of cosmological parameter estimates.
Among the methods that have been proposed for source detection, wavelet
techniques based on ``optimal'' filters have been proposed.In this paper we
show that these filters are in fact only restrictive cases of a more general
class of matched filters that optimize signal-to-noise ratio and that have, in
general, better source detection capabilities, especially for lower amplitude
sources. These conclusions are confirmed by some numerical experiments.
\keywords{Methods: data analysis -- Methods: statisticalComment: 6 pages, 3 figure
Super stellar clusters with a bimodal hydrodynamic solution: an Approximate Analytic Approach
We look for a simple analytic model to distinguish between stellar clusters
undergoing a bimodal hydrodynamic solution from those able to drive only a
stationary wind. Clusters in the bimodal regime undergo strong radiative
cooling within their densest inner regions, which results in the accumulation
of the matter injected by supernovae and stellar winds and eventually in the
formation of further stellar generations, while their outer regions sustain a
stationary wind. The analytic formulae are derived from the basic hydrodynamic
equations. Our main assumption, that the density at the star cluster surface
scales almost linearly with that at the stagnation radius, is based on results
from semi-analytic and full numerical calculations. The analytic formulation
allows for the determination of the threshold mechanical luminosity that
separates clusters evolving in either of the two solutions. It is possible to
fix the stagnation radius by simple analytic expressions and thus to determine
the fractions of the deposited matter that clusters evolving in the bimodal
regime blow out as a wind or recycle into further stellar generations.Comment: 5 pages, 4 figures, accepted by A&
Chandra view of Kes 79: a nearly isothermal SNR with rich spatial structure
A 30 ks \chandra ACIS-I observation of Kes 79 reveals rich spatial
structures, including many filaments, three partial shells, a loop and a
``protrusion''. Most of them have corresponding radio features. Regardless of
the different results from two non-equilibrium ionization (NEI) codes,
temperatures of different parts of the remnant are all around 0.7 keV, which is
surprisingly constant for a remnant with such rich structure. If thermal
conduction is responsible for smoothing the temperature gradient, a lower limit
on the thermal conductivity of 1/10 of the Spitzer value can be derived.
Thus, thermal conduction may play an important role in the evolution of at
least some SNRs. No spectral signature of the ejecta is found, which suggests
the ejecta material has been well mixed with the ambient medium. From the
morphology and the spectral properties, we suggest the bright inner shell is a
wind-driven shell (WDS) overtaken by the blast wave (the outer shell) and
estimate the age of the remnant to be 6 kyr for the assumed dynamics.
Projection is also required to explain the complicated morphology of Kes 79.Comment: 12 pages, 6 figures (3 in color), ApJ, in press, April 20, 200
Gansu Studio: 'Plug-in' school unit for rural China
Gansú ‘Plug-in’ Studio was a community outreach project based in China developed over a course of 2 years (2014-2016). It proposed a complementary approach of education to improve quality of learning in primary schools in rural areas. The premise for the work was to engage higher education institutions such as UNNC and primary education institutions, such as HEPAN, by exchange of resources, (e.g. physical or human - staff and students as well as contexts as real opportunities for learning). It worked using design as a tool for development and environmental awareness. It worked in partnership with industry and government institutions and it involved over 120 students and 15 staff from 5 different areas (Architecture, Product Design, Environmental Engineering, Film Studies and English/Education). Through interactive workshops with academics and industry practitioners, UNNC students were guided to realise their ideas through innovative design and sustainable engineering solutions, also developed their communication and team working skills for real to help rural education and community development.
Meanwhile, pupils and teachers in rural areas could develop sufficiently as their urban counterparts through this connected learning hub. The purpose of this paper is to discuss the processes and outcomes of Gansu Studio. The Plug-in Gansu Unit was designed to be the first net positive energy rural school building in China producing an estimated 18304 kWh/year of renewable energy to the school and reverting back to the county grid an annual extra clean energy 2304kWh/annum upon completion. An estimated 22 tons of water per year would be also saved
Star clusters and the structure of the ISM. Tunnels and wakes in giant extragalactic HII regions
Several structures have been discovered embedded in regions of recent or
ongoing star formation, which point to the importance of the interaction
between fast moving wind-blowing stars and their environment. Using
hydrodynamic simulations, we investigate the passage through the interstellar
medium of a supersonic stellar wind source, and show how it can naturally lead
to the formation of tubes, channels and swamps of globules as interfaces are
crossed. The results are in excellent agreement with observation of 30 Doradus.Comment: 12 pages + 5 figures (GIF format) - Accepted for pub. in Astrophys.
J. Letter
Drivers of Business-to-Business (B2B) Sales Success and the role of Digitalization after COVID-19 Disruptions
Purpose - The purpose of this research is to investigate the drivers of business-to-business sales success and the role of digitalization, in a selling and sales management landscape being disrupted by COVID-19.
Design/methodology/approach – The methodology follows a discovery-oriented grounded theory approach which consists of a two-stage qualitative study with sales professionals in Chile, and a Fuzzy-Set Qualitative Comparative Analysis (fsQCA).
Findings - This research shows that interfunctional coordination, agility in the selling process, and business customer engagement are critical determinants of B2B sales success, while digitalization moderates these relationships.
Originality/value - This research responds to a call for more research on the impact of digitalization on business relationships in different contexts and perspectives. We study the Chilean context, through a two-stage qualitative study, and a fsQCA analysis, which constitutes a novel combination in this stream of research
Una mirada género sensitiva a los derechos humanos y al interés superior de la persona menor de edad en el sistema de justicia penal juvenil, en el Juzgado Penal Juvenil de San José, durante el año 2006
Trabajo Final de Graduación para la MaestrÃa en Estudio de la Violencia Social y Familiar compuesto de 197 páginas en formato PDF.El proceso de elaboración de este trabajo tiene como objetivo central el determinar desde un enfoque de Derechos Humanos con Perspectiva de Género, la inconsistencia al cumplimiento del Principio Rector Interés Superior de las personas menores de edad. Para ello, se analizaron once procesos judiciales tramitados en el Juzgado Penal Juvenil de San José, durante el año 2006.
Lo anterior adquiere sentido, a partir de la revisión de los respectivos expedientes, y se ve reflejada en las voces de las personas menores de edad entrevistadas y entrevistados y de los y las participantes en el grupo focal. Asà como de la valiosas información y reflexiones señaladas por expertos y expertas en la materia Penal Juvenil. En lo referente a la intervención de las instituciones del Estado, obligados por ley al abordaje de la materia hacia las personas menores de edad. Se contó con la colaboración de las y los operadores de justicia.
De manera que se identifican, puntos de vista adultocéntricas y sexistas, contrarios con el Principio del Interés Superior de las personas menores de edad, y con el ordenamiento jurÃdico tanto nacional como internacional. Estos planteamientos se relacionan con el Enfoque de Género y Derechos Humanos.
Desde el enfoque cualitativo utilizando un método de triangulación de la información.
Este trabajo pretende revelar la insatisfacción de las personas menores de edad vÃctimas que acuden al sistema de justicia, asà como la incapacidad institucional detectada para dar respuesta inmediata al interés superior del menor de edad.Universidad Estatal a Distancia de Costa Ric
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