382 research outputs found
Instrumentos normativos de gestão sustentável e a sua relação com a responsabilidade socioambiental empresarial
Orientador : Prof. Dr. Alexandre França TettoMonografia (especialização) - Universidade Federal do Paraná, Setor de Ciências Agrárias, Curso de Especialização em Economia e Meio AmbienteInclui referênciasResumo : A responsabilidade socioambiental tornou-se um tema em evidência, de sorte que muitos instrumentos de gestão foram criados para subsidiar o processo de comprometimento das empresas com uma sociedade mais sustentável. A nova dinâmica econômica de crescer de forma sustentável, com uso racional dos recursos naturais, ampliou as discussões sobre o papel e a atuação das organizações induzindo a criação de novos modelos de gestão que incluam compromissos com a responsabilidade socioambiental. O escopo desta pesquisa foi o tema sobre os instrumentos normativos de gestão sustentável e a sua relação com a responsabilidade socioambiental das empresas. Seu alicerce central foi de analisar estas ferramentas utilizadas pelas organizações integrando-as com a busca de transformar estes valores em estratégias competitivas. A metodologia utilizada foi qualitativa com perspectivas na abordagem bibliográfica e descritiva sobre os principais instrumentos de gestão sustentável e a sua integração com a responsabilidade socioambiental nas empresas. Identificou-se que os instrumentos de gestão possuem variadas associações com os princípios da responsabilidade socioambiental nas organizações, constatando-se que há instrumentos de gestão comparativamente mais efetivos e complementaridade entre alguns deles. Os resultados deste estudo demostraram que a utilização dos instrumentos de gestão sustentável pode conduzir a importantes melhorias nos processos de gestão empresarial além de proporcionar incrementos tanto financeiros como na imagem institucional das organizações. Verificou-se também que a integração entre os sistemas de gestão ambiental e gerencial nas empresas pode agregar maior eficiência nos controles internos, com consequente redução nos custos, mão-de-obra e tempo. Concluiu-se finalmente que a responsabilidade socioambiental e a sustentabilidade empresarial não são irreconciliáveiscom o crescimento econômico, ao contrário, podem ser importantes agregadores de vantagens competitivas para as organizaçõese de geração de valor para acionistas, além de proporcionar relevantes benefícios à sociedade
Social networks for reading as a new Literary Training Space
In contrast to the generalized negative vision regarding the use of social networks, this study aims to analyze their present possibilities for the dissemination of literature and for the development of literary education. In that respect, the concepts of social reading and LIJ 2.0 are presented as a case of Internet participation
dynamics related to the development of reading habits. Next, the main social reading networks whose main objective is to talk about literature are presented. The main objective of this work is to present several specific uses for the promotion of reading in common social networks such as Facebook, Twitter or Instagram and in specific reading networks such as Goodreads or the Spanish Entrelectores and Leoteca.This study is part of the Research Project: Proyecto de Investigación Emergente de la Universidad de Alicante GRE 16–05: “Literatura Infantil y Juvenil en Internet. LIJ 2.0 Análisis de Aplicaciones y Redes sociales de lectura”
Proton drip-line nuclei in Relativistic Hartree-Bogoliubov theory
Ground-state properties of spherical even-even nuclei and
are described in the framework of Relativistic Hartree Bogoliubov
(RHB) theory. The model uses the NL3 effective interaction in the mean-field
Lagrangian, and describes pairing correlations by the pairing part of the
finite range Gogny interaction D1S. Binding energies, two-proton separation
energies, and proton radii that result from fully self-consistent RHB
solutions are compared with experimental data. The model predicts the location
of the proton drip-line. The isospin dependence of the effective spin-orbit
potential is discussed, as well as pairing properties that result from the
finite range interaction in the channel.Comment: 12 pages, RevTex, 10 p.s figures, submitted to Phys. Rev.
An Unequivocal Synthesis of 2-Aryl Substituted 3-Amino-2,4,5,7-tetrahydro-6H-pyrazolo[3,4-b]pyridin-6-ones
The reaction between pyridones (1) and substituted hydrazines 4 can afford two different regioisomeric pyrazolo[3,4-b]pyridin - 6-ones 2 and 3 depending on the initial substitution of the methoxy group and the direction of the cyclization. In the case of phenylhydrazine 4 (R3 = Ph), we have clearly shown that the treatment of pyridones 1a-d with 4 (R3 = Ph) in MeOH at temperatures below 1408C yields, independently of the nature and position of the substituents present in the pyridone ring, the open intermediates 7a-d. When the reaction is carried at 1408C under microwave irradiation, the corresponding 2-aryl substituted pyrazolo[3,4-b]pyridines 3a-d are always formed. We have experimentally determined, using DSC techniques, the activation energies of the two steps involved in the formation of 3: a) substitution of the methoxy group present in pyridones 1 with phenylhydrazine 4 (R3 = Ph) to afford intermediates 7 and b) cyclization of intermediates 7 to yield pyrazolopyridines 3. The results obtained, 15 and 42 kcal·mol 1 respectively, are in agreement with the experimental findings
First detection of a VHE gamma-ray spectral maximum from a Cosmic source: H.E.S.S. discovery of the Vela X nebula
The Vela supernova remnant (SNR) is a complex region containing a number of
sources of non-thermal radiation. The inner section of this SNR, within 2
degrees of the pulsar PSR B0833-45, has been observed by the H.E.S.S. gamma-ray
atmospheric Cherenkov detector in 2004 and 2005. A strong signal is seen from
an extended region to the south of the pulsar, within an integration region of
radius 0.8 deg. around the position (RA = 08h 35m 00s, dec = -45 deg. 36'
J2000.0). The excess coincides with a region of hard X-ray emission seen by the
ROSAT and ASCA satellites. The observed energy spectrum of the source between
550 GeV and 65 TeV is well fit by a power law function with photon index = 1.45
+/- 0.09(stat) +/- 0.2(sys) and an exponential cutoff at an energy of 13.8 +/-
2.3(stat) +/- 4.1(sys) TeV. The integral flux above 1 TeV is (1.28 +/- 0.17
(stat) +/- 0.38(sys)) x 10^{-11} cm^{-2} s^{-1}. This result is the first clear
measurement of a peak in the spectral energy distribution from a VHE gamma-ray
source, likely related to inverse Compton emission. A fit of an Inverse Compton
model to the H.E.S.S. spectral energy distribution gives a total energy in
non-thermal electrons of ~2 x 10^{45} erg between 5 TeV and 100 TeV, assuming a
distance of 290 parsec to the pulsar. The best fit electron power law index is
2.0, with a spectral break at 67 TeV.Comment: 5 pages, 4 figures, accepted for publication in Astronomy and
Astrophysics letter
A possible association of the new VHE gamma-ray source HESS J1825--137 with the pulsar wind nebula G18.0--0.7
We report on a possible association of the recently discovered very
high-energy -ray source HESS J1825--137 with the pulsar wind nebula
(commonly referred to as G 18.0--0.7) of the year old
Vela-like pulsar PSR B1823--13. HESS J1825--137 was detected with a
significance of 8.1 in the Galactic Plane survey conducted with the
H.E.S.S. instrument in 2004. The centroid position of HESS J1825--137 is offset
by 11\arcmin south of the pulsar position. \emph{XMM-Newton} observations have
revealed X-ray synchrotron emission of an asymmetric pulsar wind nebula
extending to the south of the pulsar. We argue that the observed morphology and
TeV spectral index suggest that HESS J1825--137 and G 18.0--0.7 may be
associated: the lifetime of TeV emitting electrons is expected to be longer
compared to the {\it XMM-Newton} X-ray emitting electrons, resulting in
electrons from earlier epochs (when the spin-down power was larger)
contributing to the present TeV flux. These electrons are expected to be
synchrotron cooled, which explains the observed photon index of , and
the longer lifetime of TeV emitting electrons naturally explains why the TeV
nebula is larger than the X-ray size. Finally, supernova remnant expansion into
an inhomogeneous medium is expected to create reverse shocks interacting at
different times with the pulsar wind nebula, resulting in the offset X-ray and
TeV -ray morphology.Comment: 5 pages, 3 figures, to appear in Astronomy and Astrophysics Letter
3.9 day orbital modulation in the TeV gamma-ray flux and spectrum from the X-ray binary LS 5039
New observations of LS 5039, a High Mass X-ray Binary comprising a massive
star and compact object, were carried out with the High Energy Stereoscopic
System of Cherenkov Telescopes (H.E.S.S.) in 2005 at very high energy (VHE)
gamma-ray energies. These observations reveal that its flux and energy spectrum
are modulated with the 3.9 day orbital period of the binary system. This is the
first time in gamma-ray astronomy that orbital modulation has been observed,
and periodicity clearly established using ground-based gamma-ray detectors. The
VHE gamma-ray emission is largely confined to half of the orbit, peaking around
the inferior conjunction epoch of the compact object. For this epoch, there is
also a hardening of the energy spectrum in the energy range between 0.2 TeV and
a few TeV. The flux vs. orbital phase profile provides the first clear
indication of gamma-ray absorption via pair production within an astrophysical
source, a process which is expected to occur if the gamma-ray production site
is situated within ~1 AU of the compact object. Moreover the production region
size must be not significantly greater than the binary separation (~0.15 AU).
Notably, these constraints are also considerably smaller than the collimated
outflows or jets (extending out to ~1000 AU) observed in LS 5039. The spectral
hardening could arise from variations with phase in the maximum electron
energies, and/or the dominant VHE gamma-ray production mechanism.Comment: 8 pages, 8 figures, accepted for publication in Astronomy &
Astrophysic
H.E.S.S. observations of gamma-ray bursts in 2003-2007
Very-high-energy (VHE; >~100 GeV) gamma-rays are expected from gamma-ray
bursts (GRBs) in some scenarios. Exploring this photon energy regime is
necessary for understanding the energetics and properties of GRBs. GRBs have
been one of the prime targets for the H.E.S.S. experiment, which makes use of
four Imaging Atmospheric Cherenkov Telescopes (IACTs) to detect VHE gamma-rays.
Dedicated observations of 32 GRB positions were made in the years 2003-2007 and
a search for VHE gamma-ray counterparts of these GRBs was made. Depending on
the visibility and observing conditions, the observations mostly start minutes
to hours after the burst and typically last two hours. Results from
observations of 22 GRB positions are presented and evidence of a VHE signal was
found neither in observations of any individual GRBs, nor from stacking data
from subsets of GRBs with higher expected VHE flux according to a
model-independent ranking scheme. Upper limits for the VHE gamma-ray flux from
the GRB positions were derived. For those GRBs with measured redshifts,
differential upper limits at the energy threshold after correcting for
absorption due to extra-galactic background light are also presented.Comment: 9 pages, 4 tables, 3 figure
Discovery of VHE gamma-rays from the high-frequency-peaked BL Lac object RGB J0152+017
Aims: The BL Lac object RGB J0152+017 (z=0.080) was predicted to be a very
high-energy (VHE; > 100 GeV) gamma-ray source, due to its high X-ray and radio
fluxes. Our aim is to understand the radiative processes by investigating the
observed emission and its production mechanism using the High Energy
Stereoscopic System (H.E.S.S.) experiment. Methods: We report recent
observations of the BL Lac source RGB J0152+017 made in late October and
November 2007 with the H.E.S.S. array consisting of four imaging atmospheric
Cherenkov telescopes. Contemporaneous observations were made in X-rays by the
Swift and RXTE satellites, in the optical band with the ATOM telescope, and in
the radio band with the Nancay Radio Telescope. Results: A signal of 173
gamma-ray photons corresponding to a statistical significance of 6.6 sigma was
found in the data. The energy spectrum of the source can be described by a
powerlaw with a spectral index of 2.95+/-0.36stat+/-0.20syst. The integral flux
above 300 GeV corresponds to ~2% of the flux of the Crab nebula. The source
spectral energy distribution (SED) can be described using a two-component
non-thermal synchrotron self-Compton (SSC) leptonic model, except in the
optical band, which is dominated by a thermal host galaxy component. The
parameters that are found are very close to those found in similar SSC studies
in TeV blazars. Conclusions: RGB J0152+017 is discovered as a source of VHE
gamma-rays by H.E.S.S. The location of its synchrotron peak, as derived from
the SED in Swift data, allows clearly classification it as a
high-frequency-peaked BL Lac (HBL).Comment: Accepted for publication in A&A Letters (5 pages, 4 figures
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