1,009 research outputs found
Análise cienciométrica de espaços verdes urbanos e seus serviços ecossistêmicos.
O acelerado crescimento populacional e urbano nas últimas décadas intensificou a necessidade de pesquisas sobre o ecossistema urbano e os serviços por ele oferecidos, visando ao bem-estar da população urbana por meio da conservação da natureza. O reconhecimento dos serviços ecossistêmicos fornecidos pelos Espaços Verdes Urbanos (EVUs) pode subsidiar a tomada de decisão para que as cidades promovam o desenvolvimento sustentável, conservando e/ou restaurando os serviços ecossistêmicos e a biodiversidade, para que a vida das pessoas nas cidades seja viável diante dos desafios impostos pelas mudanças climáticas. Este artigo tem por objetivo principal avaliar como os serviços ecossistêmicos fornecidos pelos EVUs estão sendo abordados no meio cientÃfico. Realizou-se um levantamento cienciométrico e, posteriormente, uma análise bibliográfica dos principais artigos para avaliar o conhecimento cientÃfico atual, as principais limitações teóricas e as lacunas e oportunidades para avanços no conhecimento sobre o tema. Os resultados apontam que as pesquisas dos serviços ecossistêmicos em EVUs foram intensificadas a partir de 2005 e apresentaram uma taxa exponencial de crescimento de 30% ao ano, particularmente nos paÃses mais desenvolvidos. A análise bibliográfica aponta que os serviços ecossistêmicos reguladores e culturais no contexto urbano são aqueles de maior importância, e que são necessárias novas metodologias para avaliar e eventualmente precificar esses serviços
On the estimate of the sigma^(I = 1)_(KN)(0)-term value from the energy level shift of kaonic hydrogen in the ground state
Using the experimental data on the energy level shift of kaonic hydrogen in
the ground state (the DEAR Collaboration, Phys. Rev. Lett. 94, 212302 (2005))
and the theoretical value of the energy level shift, calculated within the
phenomenological quantum field theoretic approach to the description of strong
low-energy anti-K N and anti-K NN interactions developed at Stefan Meyer
Institut fuer subatomare Physik in Vienna, we estimate the value of the
sigma^(I = 1)_(KN)(0)-term of low-energy anti-K N scattering. We get sigma^(I =
1)_(KN)(0) = (433 +/- 85) MeV. This testifies the absence of strange quarks in
the proton structure.Comment: 7 pages, no figure
VIP: An Experiment to Search for a Violation of the Pauli Exclusion Principle
The Pauli Exclusion Principle is a basic principle of Quantum Mechanics, and
its validity has never been seriously challenged. However, given its
fundamental standing, it is very important to check it as thoroughly as
possible. Here we describe the VIP (VIolation of the Pauli exclusion principle)
experiment, an improved version of the Ramberg and Snow experiment (E. Ramberg
and G. Snow, {\it Phys. Lett. B} {\bf 238}, 438 (1990)); VIP has just completed
the installation at the Gran Sasso underground laboratory, and aims to test the
Pauli Exclusion Principle for electrons with unprecedented accuracy, down to
. We report preliminary experimental
results and briefly discuss some of the implications of a possible violation.Comment: Plenary talk presented by E. Milotti at Meson 2006, Cracow, 9-13 June
200
New experimental limit on the Pauli Exclusion Principle violation by electrons
The Pauli Exclusion Principle (PEP) is one of the basic principles of modern
physics and, even if there are no compelling reasons to doubt its validity, it
is still debated today because an intuitive, elementary explanation is still
missing, and because of its unique stand among the basic symmetries of physics.
The present paper reports a new limit on the probability that PEP is violated
by electrons, in a search for a shifted K line in copper: the presence
of this line in the soft X-ray copper fluorescence would signal a transition to
a ground state already occupied by 2 electrons. The obtained value, , improves the existing limit by almost two
orders of magnitude.Comment: submitted to Phys. Lett.
Shedding New Light on Kaon-Nucleon/Nuclei Interaction and Its Astrophysical Implications with the AMADEUS Experiment at DAFNE
The AMADEUS experiment deals with the investigation of the low-energy
kaon-nuclei hadronic interaction at the DA{\Phi}NE collider at LNF-INFN, which
is fundamental to respond longstanding questions in the non-perturbative QCD
strangeness sector. The antikaon-nucleon potential is investigated searching
for signals from possible bound kaonic clusters, which would open the
possibility for the formation of cold dense baryonic matter. The confirmation
of this scenario may imply a fundamental role of strangeness in astrophysics.
AMADEUS step 0 consisted in the reanalysis of 2004/2005 KLOE dataset,
exploiting K- absorptions in H, 4He, 9Be and 12C in the setup materials. In
this paper, together with a review on the multi-nucleon K- absorption and the
particle identification procedure, the first results on the {\Sigma}0-p channel
will be presented including a statistical analysis on the possible accomodation
of a deeply bound stateComment: 6 pages, 2 figure, 1 table, HADRON 2015 conferenc
Observation of a narrow baryon resonance with positive strangeness formed in Xe collisions
The charge-exchange reaction K^+ Xe --> K^0 p Xe' is investigated using the
data of the DIANA experiment. The distribution of the pK^0 effective mass shows
a prominent enhancement near 1538 MeV formed by \sim 80 events above the
background, whose width is consistent with being entirely due to the
experimental resolution. Under the selections based on a simulation of K^+Xe
collisions, the statistical significance of the signal reaches 5.5\sigma. We
interpret this observation as strong evidence for formation of a pentaquark
baryon with positive strangeness, \Theta^+(uudd\bar{s}), in the charge-exchange
reaction K^+ n --> K^0 p on a bound neutron. The mass of the \Theta^+ baryon is
measured as m(\Theta^+) = 1538+-2 MeV. Using the ratio between the numbers of
resonant and non-resonant charge-exchange events in the peak region, the
intrinsic width of this baryon resonance is determined as \Gamma(\Theta^+) =
0.34+-0.10 MeV.Comment: 19 pages, 8 figure
New experimental limit on Pauli Exclusion Principle violation by electrons (the VIP experiment)
The Pauli Exclusion Principle is one of the basic principles of modern
physics and is at the very basis of our understanding of matter: thus it is
fundamental importance to test the limits of its validity. Here we present the
VIP (Violation of the Pauli Exclusion Principle) experiment, where we search
for anomalous X-rays emitted by copper atoms in a conductor: any detection of
these anomalous X-rays would mark a Pauli-forbidden transition. ] VIP is
currently taking data at the Gran Sasso underground laboratories, and its
scientific goal is to improve by at least four orders of magnitude the previous
limit on the probability of Pauli violating transitions, bringing it into the
10**-29 - 10**-30 region. First experimental results, together with future
plans, are presented.Comment: To appear in proceedings of the XLVI International Winter Meeting on
Nuclear Physics, Bormio, Italy, January 20-26, 200
The VIP Experiment
The Pauli Exclusion Principle (PEP) is a basic principle of Quantum
Mechanics, and its validity has never been seriously challenged. However, given
its importance, it is very important to check it as thoroughly as possible.
Here we describe the VIP (Violation of PEP) experiment, an improved version of
the Ramberg and Snow experiment (Ramberg and Snow, Phys. Lett. B238 (1990)
438); VIP shall be performed at the Gran Sasso underground laboratories, and
aims to test the Pauli Exclusion Principle for electrons with unprecedented
accuracy, down to Comment: 7 pages, 5 figures, PDF only, presented by Edoardo Milotti to the
conference "Quantum Theory: reconsideration of foundations-3", Vaxjo
(Sweden), June, 6-11 200
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