Últimos itens adicionados do Acervo: Biblioteca Digital da Produção Intelectual e Científica da Unicamp

A Biblioteca Digital da Produção Intelectual e Científica da Unicamp tem por objetivo reunir e disseminar a produção intelectual, acadêmica e cultural da universidade e preservar sua memória institucional, além de contribuir para ampliar a visibilidade da instituição e dos seus pesquisadores em âmbito nacional e internacional.

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‣ Analysis of Vilanova Artigas' unbuilt designs in Sao Paulo

Tagliari, Ana; Perrone, Rafael; Florio, Wilson
Fonte: Editora Unisinos; Sao Leopoldo Publicador: Editora Unisinos; Sao Leopoldo
Tipo: Artigo de Revista Científica
Português
The aim of this article is to examine unbuilt residential projects designed by Vilanova Artigas. The formal and spatial conception of these projects is investigated through physical models. The object of this research project consists of the unbuilt residential projects designed by Vilanova Artigas in Sao Paulo that are available in FAUUSP's digital Library. The results indicate that physical models contribute to a better interpretation of unbuilt architectural design, both from the conceptual and aesthetic and from the functional and technical point of view. The original contribution lies in the object, i.e. the unbuilt projects, in the method, using physical models for analysis, and in the objective, viz. to establish a relationship between Artigas' built works and his unbuilt residential projects in order to better understand the design's spatial conception and its architectural approach.

‣ Physical Exercise and Antidepressants Enhance BDNF Targeting in Hippocampal CA3 Dendrites: Further Evidence of a Spatial Code for BDNF Splice Variants

Baj, Gabriele; D'Alessandro, Valentina; Musazzi, Laura; Mallei, Alessandra; Sartori, Cesar R.; Sciancalepore, Marina; Tardito, Daniela; Langone, Francesco; Popoli, Maurizio; Tongiorgi, Enrico
Fonte: Nature Publishing Group; London Publicador: Nature Publishing Group; London
Tipo: Artigo de Revista Científica
Português
Brain-derived neurotrophic factor (BDNF) is encoded by multiple BDNF transcripts, whose function is unclear. We recently showed that a subset of BDNF transcripts can traffic into distal dendrites in response to electrical activity, while others are segregated into the somatoproximal domains. Physical exercise and antidepressant treatments exert their beneficial effects through upregulation of BDNF, which is required to support survival and differentiation of newborn dentate gyrus (DG) neurons. While these DG processes are required for the antidepressant effect, a role for CA1 in antidepressant action has been excluded, and the effect on CA3 neurons remains unclear. Here, we show for the first time that physical exercise and antidepressants induce local increase of BDNF in CA3. Voluntary physical exercise for 28 consecutive days, or 2-week treatment with 10 mg/kg per day fluoxetine or reboxetine, produced a global increase of BDNF mRNA and protein in the neuronal somata of the whole hippocampus and a specific increase of BDNF in dendrites of CA3 neurons. This increase was accounted for by BDNF exon 6 variant. In cultured hippocampal neurons, application of serotonin or norepinephrine (10-50 mu M) induced increase in synaptic transmission and targeting of BDNF mRNA in dendrites. The increased expression of BDNF in CA3 dendrites following antidepressants or exercise further supports the neurotrophin hypothesis of antidepressants action and confirms that the differential subcellular localization of BDNF mRNA splice variants provides a spatial code for a selective expression of BDNF in specific subcellular districts. This selective expression may be exploited to design more specific antidepressants. Neuropsychopharmacology (2012) 37...

‣ Contribution of AT-, GC-, and methylated cytidine-rich DNA to chromatin composition in Malpighian tubule cell nuclei of Panstrongylus megistus (Hemiptera, Reduviidae)

Alvarenga, Elenice M.; Mondin, Mateus; Rodrigues, Vera L. C. C.; Andrade, Larissa M.; Vidal, Benedicto de Campos; Mello, Maria Luiza S.
Fonte: Elsevier; Jena Publicador: Elsevier; Jena
Tipo: Artigo de Revista Científica
Português
The Malpighian tubule cell nuclei of male Panstrongylus megistus, a vector of Chagas disease, contain one chromocenter, which is composed solely of the Y chromosome. Considering that different chromosomes contribute to the composition of chromocenters in different triatomini species, the aim of this study was to determine the contribution of AT-, GC-, and methylated cytidine-rich DNA in the chromocenter as well as in euchromatin of Malpighian tubule cell nuclei of P. megistus in comparison with published data for Triatoma infestans. Staining with 4',6-diamidino-2-phenylindole/actinomycin D and chromomycin A(3)/distamycin, immunodetection of 5-methylcytidine and AgNOR test were used. The results revealed AT-rich/GC-poor DNA in the male chromocenter, but equally distributed AT and GC DNA sequences in male and female euchromatin, like in T. infestans. Accumulation of argyrophilic proteins encircling the chromocenter did not always correlate with that of GC-rich DNA. Methylated DNA identified by immunodetection was found sparsely distributed in the euchromatin of both sexes and at some points around the chromocenter edge, but it could not be considered responsible for chromatin condensation in the chromocenter, like in T. infestans. However...

‣ Ascorbic acid protects the diaphragm muscle against myonecrosis in mdx mice

Tonon, Erika; Ferretti, Renato; Shiratori, Jean Hideki; Santo Neto, Humberto; Marques, Maria Julia; Minatel, Elaine
Fonte: Elsevier; New York Publicador: Elsevier; New York
Tipo: Artigo de Revista Científica
Português
Objective: Oxidative stress contributes to myonecrosis in the dystrophin-deficient fibers of mdx mice and in Duchenne's muscular dystrophy. We examined the effects of ascorbic acid (AA), an antioxidant and free radical scavenger, on the dystrophic diaphragm muscle. Methods: Mdx mice (14 d old) received AA for 14 d. Control mdx mice received saline. The muscle damage was visualized by the penetration of Evans blue dye into myofibers and the extent of inflammation was assessed by histologic analysis. Creatine kinase levels were measured for the biochemical evaluation of muscle fiber degeneration. The levels of tumor necrosis factor-alpha (a proinflammatory cytokine) and 4-hydroxynonenal (a marker of lipid peroxidation) were analyzed by immunoblotting. Results: Ascorbic acid decreased creatine kinase levels, myonecrosis, inflammation, and the levels of tumor necrosis factor-alpha and 4-hydroxynonenal. Conclusion: The present results suggest that AA plays a protective role in dystrophic muscle degeneration, possibly by decreasing reactive oxygen species, and support further investigations of AA as a potential therapy for dystrophinopathies. (C) 2012 Elsevier Inc. All rights reserved.; Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP); Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES); Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

‣ Analysis of plant LTR-retrotransposons at the fine-scale family level reveals individual molecular patterns

Domingues, Douglas S.; Cruz, Guilherme M. Q.; Metcalfe, Cushla J.; Nogueira, Fabio T. S.; Vicentini, Renato; Alves, Cristiane de S.; Van Sluys, Marie-Anne
Fonte: Biomed Central Ltd; London Publicador: Biomed Central Ltd; London
Tipo: Artigo de Revista Científica
Português
Background: Sugarcane is an important crop worldwide for sugar production and increasingly, as a renewable energy source. Modern cultivars have polyploid, large complex genomes, with highly unequal contributions from ancestral genomes. Long Terminal Repeat retrotransposons (LTR-RTs) are the single largest components of most plant genomes and can substantially impact the genome in many ways. It is therefore crucial to understand their contribution to the genome and transcriptome, however a detailed study of LTR-RTs in sugarcane has not been previously carried out. Results: Sixty complete LTR-RT elements were classified into 35 families within four Copia and three Gypsy lineages. Structurally, within lineages elements were similar, between lineages there were large size differences. FISH analysis resulted in the expected pattern of Gypsy/heterochromatin, Copia/euchromatin, but in two lineages there was localized clustering on some chromosomes. Analysis of related ESTs and RT-PCR showed transcriptional variation between tissues and families. Four distinct patterns were observed in sRNA mapping, the most unusual of which was that of Ale1, with very large numbers of 24nt sRNAs in the coding region. The results presented support the conclusion that distinct small RNA-regulated pathways in sugarcane target the lineages of LTR-RT elements. Conclusions: Individual LTR-RT sugarcane families have distinct structures...

‣ A novel linkage map of sugarcane with evidence for clustering of retrotransposon-based markers

Palhares, Alessandra C.; Rodrigues-Morais, Taislene B.; Van Sluys, Marie-Anne; Domingues, Douglas S.; Maccheroni, Walter, Jr.; Jordao, Hamilton, Jr.; Souza, Anete P.; Marconi, Thiago G.; Mollinari, Marcelo; Gazaffi, Rodrigo; Garcia, Antonio Augusto F.; Ca
Fonte: Biomed Central Ltd; London Publicador: Biomed Central Ltd; London
Tipo: Artigo de Revista Científica
Português
Background: The development of sugarcane as a sustainable crop has unlimited applications. The crop is one of the most economically viable for renewable energy production, and CO2 balance. Linkage maps are valuable tools for understanding genetic and genomic organization, particularly in sugarcane due to its complex polyploid genome of multispecific origins. The overall objective of our study was to construct a novel sugarcane linkage map, compiling AFLP and EST-SSR markers, and to generate data on the distribution of markers anchored to sequences of scIvana_1, a complete sugarcane transposable element, and member of the Copia superfamily. Results: The mapping population parents ('IAC66-6' and 'TUC71-7') contributed equally to polymorphisms, independent of marker type, and generated markers that were distributed into nearly the same number of co-segregation groups (or CGs). Bi-parentally inherited alleles provided the integration of 19 CGs. The marker number per CG ranged from two to 39. The total map length was 4,843.19 cM, with a marker density of 8.87 cM. Markers were assembled into 92 CGs that ranged in length from 1.14 to 404.72 cM, with an estimated average length of 52.64 cM. The greatest distance between two adjacent markers was 48.25 cM. The scIvana_1-based markers (56) were positioned on 21 CGs...

‣ Particle-Yield Modification in Jetlike Azimuthal Dihadron Correlations in Pb-Pb Collisions at root S-NN=2.76 TeV

Aamodt, K.; Abelev, B.; Abrahantes Quintana, A.; Adamova, D.; Adare, A. M.; Aggarwal, M. M.; Rinella, G. Aglieri; Agocs, A. G.; Agostinelli, A.; Aguilar Salazar, S.; Ahammed, Z.; Ahmad, N.; Masoodi, A. Ahmad; Ahn, S. U.; Akindinov, A.; Aleksandrov, D.; Al
Fonte: Amer Physical Soc; College Pk Publicador: Amer Physical Soc; College Pk
Tipo: Artigo de Revista Científica
Português
The yield of charged particles associated with high-pt trigger particles (8 < p(t) < 15 GeV/c) is measured with the ALICE detector in Pb-Pb collisions at root S-NN = 2.76 TeV relative to proton-proton collisions at the same energy. The conditional per-trigger yields are extracted from the narrow jetlike correlation peaks in azimuthal dihadron correlations. In the 5% most central collisions, we observe that the yield of associated charged particles with transverse momenta p(t) > 3 GeV/c on the away side drops to about 60% of that observed in pp collisions, while on the near side a moderate enhancement of 20%-30% is found.; Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP); Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

‣ Harmonic decomposition of two particle angular correlations in Pb-Pb collisions at root s(NN)=2.76 TeV

Aamodt, K.; Abelev, B.; Abrahantes Quintana, A.; Adamova, D.; Adare, A. M.; Aggarwal, M. M.; Rinella, G. Aglieri; Agocs, A. G.; Agostinelli, A.; Aguilar Salazar, S.; Ahammed, Z.; Ahmad, N.; Masoodi, A. Ahmad; Ahn, S. U.; Akindinov, A.; Aleksandrov, D.; Al
Fonte: Elsevier; Amsterdam Publicador: Elsevier; Amsterdam
Tipo: Artigo de Revista Científica
Português
Angular correlations between unidentified charged trigger (t) and associated (a) particles are measured by the ALICE experiment in Pb-Pb collisions at root s(NN) = 2.76 TeV for transverse momenta 0.25 < p(T)(t,a) < 15 GeV/c, where p(T)(t) > p(T)(a). The shapes of the pair correlation distributions are studied in a variety of collision centrality classes between 0 and 50% of the total hadronic cross section for particles in the pseudorapidity interval |eta| < 1.0. Distributions in relative azimuth Delta phi equivalent to phi(t) - phi(a) are analyzed for |Delta eta| equivalent to |eta(t) - eta(a)| > 0.8, and are referred to as "long-range correlations". Fourier components V-n Delta equivalent to < cos(n Delta phi)> are extracted from the long-range azimuthal correlation functions. If particle pairs are correlated to one another through their individual correlation to a common symmetry plane, then the pair anisotropy V-n Delta (p(T)(t), p(T)(a)) is fully described in terms of single-particle anisotropies v(n)(p(T)) as V-n Delta(p(T)(t), p(T)(a)) = v(n)(p(T)(t))v(n)(p(T)(a)). This expectation is tested for 1 <= n <= 5 by applying a global fit of all V-n Delta(p(T)(t), p(T)(a)) to obtain the best values v(n){GF}(p(T)). It is found that for 2 <= n <= 5...

‣ Light vector meson production in pp collisions at root s=7 TeV ALICE Collaboration

Abelev, B.; Abrahantes Quintana, A.; Adamova, D.; Adare, A. M.; Aggarwal, M. M.; Rinella, G. Aglieri; Agocs, A. G.; Agostinelli, A.; Aguilar Salazar, S.; Ahammed, Z.; Ahmad, N.; Masoodi, A. Ahmad; Ahn, S. U.; Akindinov, A.; Aleksandrov, D.; Alessandro, B.
Fonte: Elsevier; Amsterdam Publicador: Elsevier; Amsterdam
Tipo: Artigo de Revista Científica
Português
The ALICE experiment has measured low-mass dimuon production in pp collisions at root s = 7 TeV in the dimuon rapidity region 2.5 < y < 4. The observed dimuon mass spectrum is described as a superposition of resonance decays (eta, rho, omega, eta', phi) into muons and semi-leptonic decays of charmed mesons. The measured production cross sections for omega and phi are sigma(omega)(1 < p(t) < 5 GeV/c. 2.5 < y < 4) = 5.28 +/- 0.54(stat) +/- 0.49(syst) mb and sigma(phi)(1 < p(t) < 5 GeV/c. 2.5 < y < 4) = 0.940 +/- 0.084(stat) +/- 0.076(syst) mb. The differential cross sections d(2)sigma/dy dp(t) are extracted as a function of p(t) for omega and phi. The ratio between the rho and omega cross section is obtained. Results for the phi are compared with other measurements at the same energy and with predictions by models. (C) 2012 CERN. Published by Elsevier B.V. All rights reserved.; Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP); Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

‣ Measurement of event background fluctuations for charged particle jet reconstruction in Pb-Pb collisions at root s(NN)=2.76 TeV

Abelev, B.; Adam, J.; Adamova, D.; Adare, A. M.; Aggarwal, M. M.; Rinella, G. Aglieri; Agocs, A. G.; Agostinelli, A.; Aguilar Salazar, S.; Ahammed, Z.; Ahmad, N.; Masood, A. Ahmad; Ahn, S. U.; Akindinov, A.; Aleksandrov, D.; Alessandro, B.; Alfaro Molina,
Fonte: Springer; New York Publicador: Springer; New York
Tipo: Artigo de Revista Científica
Português
The effect of event background fluctuations on charged particle jet reconstruction in Pb-Pb collisions at root s(NN) = 2.76 TeV has been measured with the ALICE experiment. The main sources of non-statistical fluctuations are characterized based purely on experimental data with an unbiased method, as well as by using single high p(t) particles and simulated jets embedded into real Pb-Pb events and reconstructed with the anti-k(t) jet finder. The influence of a low transverse momentum cut-off on particles used in the jet reconstruction is quantified by varying the minimum track p(t) between 0.15 GeV/c and 2 GeV/c. For embedded jets reconstructed from charged particles with p(t) > 0.15 GeV/c, the uncertainty in the reconstructed jet transverse momentum due to the heavy-ion background is measured to be 11.3 GeV/c (standard deviation) for the 10% most central Pb-Pb collisions, slightly larger than the value of 11.0 GeV/c measured using the unbiased method. For a higher particle transverse momentum threshold of 2 GeV/c, which will generate a stronger bias towards hard fragmentation in the jet finding process, the standard deviation of the fluctuations in the reconstructed jet transverse momentum is reduced to 4.8-5.0 GeV/c for the 10% most central events. A non-Gaussian tail of the momentum uncertainty is observed and its impact on the reconstructed jet spectrum is evaluated for varying particle momentum thresholds...

‣ Multi-strange baryon production in pp collisions at root s=7 TeV with ALICE

Abelev, B.; Adam, J.; Adamova, D.; Adare, A. M.; Aggarwal, M. M.; Rinella, G. Aglieri; Agocs, A. G.; Agostinelli, A.; Aguilar Salazar, S.; Ahammed, Z.; Ahmad, N.; Masoodi, A. Ahmad; Ahn, S. U.; Akindinov, A.; Aleksandrov, D.; Alessandro, B.; Alfaro Molina
Fonte: Elsevier; Amsterdam Publicador: Elsevier; Amsterdam
Tipo: Artigo de Revista Científica
Português
A measurement of the multi-strange Xi(-) and Omega(-) baryons and their antiparticles by the ALICE experiment at the CERN Large Hadron Collider (LHC) is presented for inelastic proton-proton collisions at a centre-of-mass energy of 7 TeV. The transverse momentum (p(T)) distributions were studied at mid-rapidity (vertical bar y vertical bar < 0.5) in the range of 0.6 < p(T) < 8.5 GeV/c Xi(-) for and Xi(+) baryons, and in the range of 0.8 < P-T < 5 GeV/c for Omega(-) and<(Omega)over bar>(+). Baryons and antibaryons were measured as separate particles and we find that the baryon to antibaryon ratio of both particle species is consistent with unity over the entire range of the measurement. The statistical precision of the current data has allowed us to measure a difference between the mean p(T) of Xi(-) ((Xi) over bar)(+) and Omega(-) ((Omega) over bar (+)). Particle yields, mean pi, and the spectra in the intermediate pi range are not well described by the PYTHIA Perugia 2011 tune Monte Carlo event generator, which has been tuned to reproduce the early LHC data. The discrepancy is largest for Omega(-)((Omega) over bar (+)). This PYTHIA tune approaches the pi spectra of Xi(-) and Xi(+) baryons below p(T) <0.85 GeV/c and describes the Xi(-) and Xi(+) spectra above p(T) > 6.0 GeV/c. We also illustrate the difference between the experimental data and model by comparing the corresponding ratios of (Omega(-) +(Omega) over bar (+))/(Xi(-) + Xi(+)) as a function of transverse mass. (C) 2012 CERN. Published by Elsevier B.V. All rights reserved.; Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP); Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

‣ Heavy flavour decay muon production at forward rapidity in proton-proton collisions at root s=7 TeV

Abelev, B.; Adam, J.; Adamova, D.; Adare, A. M.; Aggarwal, M. M.; Rinella, G. Aglieri; Agocs, A. G.; Agostinelli, A.; Aguilar Salazar, S.; Ahammed, Z.; Ahmad, N.; Masoodi, A. Ahmad; Ahn, S. U.; Akindinov, A.; Aleksandrov, D.; Alessandro, B.; Alfaro Molina
Fonte: Elsevier; Amsterdam Publicador: Elsevier; Amsterdam
Tipo: Artigo de Revista Científica
Português
The production of muons from heavy flavour decays is measured at forward rapidity in proton-proton collisions at root s = 7 TeV collected with the ALICE experiment at the LHC. The analysis is carried out on a data sample corresponding to an integrated luminosity L-int = 16.5 nb(-1). The transverse momentum and rapidity differential production cross sections of muons from heavy flavour decays are measured in the rapidity range 2.5 < y <4, over the transverse momentum range 2 < p(t) < 12 GeV/c. The results are compared to predictions based on perturbative QCD calculations. (C) 2012 CERN. Published by Elsevier B.V. All rights reserved.; Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP); Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

‣ J/psi Suppression at Forward Rapidity in Pb-Pb Collisions at root s(NN)=2.76 TeV

Abelev, B.; Adam, J.; Adamova, D.; Adare, A. M.; Aggarwal, M. M.; Rinella, G. Aglieri; Agocs, A. G.; Agostinelli, A.; Aguilar Salazar, S.; Ahammed, Z.; Masoodi, A. Ahmad; Ahmad, N.; Ahn, S. U.; Akindinov, A.; Aleksandrov, D.; Alessandro, B.; Alfaro Molina
Fonte: Amer Physical Soc; College Pk Publicador: Amer Physical Soc; College Pk
Tipo: Artigo de Revista Científica
Português
The ALICE experiment has measured the inclusive J/psi production in Pb-Pb collisions at root s(NN) = 2.76 TeV down to zero transverse momentum in the rapidity range 2.5 < y < 4. A suppression of the inclusive J/psi yield in Pb-Pb is observed with respect to the one measured in pp collisions scaled by the number of binary nucleon-nucleon collisions. The nuclear modification factor, integrated over the 0%-80% most central collisions, is 0.545 +/- 0.032(stat) +/- 0.083dsyst_ and does not exhibit a significant dependence on the collision centrality. These features appear significantly different from measurements at lower collision energies. Models including J/psi production from charm quarks in a deconfined partonic phase can describe our data.; Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP); Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

‣ J/psi Polarization in pp Collisions at root s=7 TeV

Abelev, B.; Quintana, A. Abrahantes; Adamova, D.; Adare, A. M.; Aggarwal, M. M.; Rinella, G. Aglieri; Agocs, A. G.; Agostinelli, A.; Aguilar Salazar, S.; Ahammed, Z.; Ahmad, N.; Masoodi, A. Ahmad; Ahn, S. U.; Akindinov, A.; Aleksandrov, D.; Alessandro, B.
Fonte: Amer Physical Soc; College Pk Publicador: Amer Physical Soc; College Pk
Tipo: Artigo de Revista Científica
Português
The ALICE Collaboration has studied J/psi production in pp collisions at root s = 7 TeV at the LHC through its muon pair decay. The polar and azimuthal angle distributions of the decay muons were measured, and results on the J/psi polarization parameters lambda(theta) and lambda(phi) were obtained. The study was performed in the kinematic region 2: 5 < y < 4, 2 < p(t) < 8 GeV/c, in the helicity and Collins-Soper reference frames. In both frames, the polarization parameters are compatible with zero, within uncertainties.; Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP); Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

‣ Underlying Event measurements in pp collisions at root s=0.9 and 7 TeV with the ALICE experiment at the LHC

Abelev, Betty; Abrahantes Quintana, Arian; Adamova, Dagmar; Adare, Andrew Marshall; Aggarwal, Madan; Rinella, Gianluca Aglieri; Agocs, Andras Gabor; Agostinelli, Andrea; Aguilar Salazar, Saul; Ahammed, Zubayer; Ahmad, Nazeer; Ahmad, Arshad; Ahn, Sang Un;
Fonte: Springer; New York Publicador: Springer; New York
Tipo: Artigo de Revista Científica
Português
We present measurements of Underlying Event observables in pp collisions at root s = 0 : 9 and 7 TeV. The analysis is performed as a function of the highest charged-particle transverse momentum p(T),L-T in the event. Different regions are defined with respect to the azimuthal direction of the leading (highest transverse momentum) track: Toward, Transverse and Away. The Toward and Away regions collect the fragmentation products of the hardest partonic interaction. The Transverse region is expected to be most sensitive to the Underlying Event activity. The study is performed with charged particles above three different p(T) thresholds: 0.15, 0.5 and 1.0 GeV/c. In the Transverse region we observe an increase in the multiplicity of a factor 2-3 between the lower and higher collision energies, depending on the track p(T) threshold considered. Data are compared to PYTHIA 6.4, PYTHIA 8.1 and PHOJET. On average, all models considered underestimate the multiplicity and summed p(T) in the Transverse region by about 10-30%.; Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP); Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

‣ SEARCH FOR POINT-LIKE SOURCES OF ULTRA-HIGH ENERGY NEUTRINOS AT THE PIERRE AUGER OBSERVATORY AND IMPROVED LIMIT ON THE DIFFUSE FLUX OF TAU NEUTRINOS

Abreu, P.; Aglietta, M.; Ahlers, M.; Ahn, E. J.; Albuquerque, I. F. M.; Allard, D.; Allekotte, I.; Allen, J.; Allison, P.; Almela, A.; Alvarez Castillo, J.; Alvarez-Muniz, J.; Alves Batista, R.; Ambrosio, M.; Aminaei, A.; Anchordoqui, L.; Andringa, S.; An
Fonte: IOP Publishing Ltd; Bristol Publicador: IOP Publishing Ltd; Bristol
Tipo: Artigo de Revista Científica
Português
The surface detector array of the Pierre Auger Observatory can detect neutrinos with energy E-nu between 10(17) eV and 10(20) eV from point-like sources across the sky south of +55 degrees and north of -65 degrees declinations. A search has been performed for highly inclined extensive air showers produced by the interaction of neutrinos of all flavors in the atmosphere (downward-going neutrinos), and by the decay of tau leptons originating from tau neutrino interactions in Earth's crust (Earth-skimming neutrinos). No candidate neutrinos have been found in data up to 2010 May 31. This corresponds to an equivalent exposure of similar to 3.5 years of a full surface detector array for the Earth-skimming channel and similar to 2 years for the downward-going channel. An improved upper limit on the diffuse flux of tau neutrinos has been derived. Upper limits on the neutrino flux from point-like sources have been derived as a function of the source declination. Assuming a differential neutrino flux k(PS) . E-nu(-2). from a point-like source, 90% confidence level upper limits for k(PS) at the level of approximate to 5x10(-7) and 2.5x10(-6) GeV cm(-2) s(-1) have been obtained over a broad range of declinations from the searches for Earth-skimming and downward-going neutrinos...

‣ The rapid atmospheric monitoring system of the Pierre Auger Observatory

Abreu, P.; Aglietta, M.; Ahlers, M.; Ahn, E. J.; Albuquerque, I. F. M.; Allard, D.; Allekotte, I.; Allen, J.; Allison, P.; Almela, A.; Alvarez Castillo, J.; Alvarez-Muniz, J.; Alves Batista, R.; Ambrosio, M.; Aminaei, A.; Anchordoqui, L.; Andringa, S.; An
Fonte: IOP Publishing Ltd; Bristol Publicador: IOP Publishing Ltd; Bristol
Tipo: Artigo de Revista Científica
Português
The Pierre Auger Observatory is a facility built to detect air showers produced by cosmic rays above 10(17) eV. During clear nights with a low illuminated moon fraction, the UV fluorescence light produced by air showers is recorded by optical telescopes at the Observatory. To correct the observations for variations in atmospheric conditions, atmospheric monitoring is performed at regular intervals ranging from several minutes (for cloud identification) to several hours (for aerosol conditions) to several days (for vertical profiles of temperature, pressure, and humidity). In 2009, the monitoring program was upgraded to allow for additional targeted measurements of atmospheric conditions shortly after the detection of air showers of special interest, e. g., showers produced by very high-energy cosmic rays or showers with atypical longitudinal profiles. The former events are of particular importance for the determination of the energy scale of the Observatory, and the latter are characteristic of unusual air shower physics or exotic primary particle types. The purpose of targeted (or "rapid") monitoring is to improve the resolution of the atmospheric measurements for such events. In this paper, we report on the implementation of the rapid monitoring program and its current status. The rapid monitoring data have been analyzed and applied to the reconstruction of air showers of high interest...

‣ A SEARCH FOR POINT SOURCES OF EeV NEUTRONS

Abreu, P.; Aglietta, M.; Ahlers, M.; Ahn, E. J.; Albuquerque, I. F. M.; Allard, D.; Allekotte, I.; Allen, J.; Allison, P.; Almela, A.; Alvarez Castillo, J.; Alvarez-Muniz, J.; Batista, R. Alves; Ambrosio, M.; Aminaei, A.; Anchordoqui, L.; Andringa, S.; An
Fonte: IOP Publishing Ltd; Bristol Publicador: IOP Publishing Ltd; Bristol
Tipo: Artigo de Revista Científica
Português
A thorough search of the sky exposed at the Pierre Auger Cosmic Ray Observatory reveals no statistically significant excess of events in any small solid angle that would be indicative of a flux of neutral particles from a discrete source. The search covers from -90 degrees to +15 degrees in declination using four different energy ranges above 1 EeV (10(18) eV). The method used in this search is more sensitive to neutrons than to photons. The upper limit on a neutron flux is derived for a dense grid of directions for each of the four energy ranges. These results constrain scenarios for the production of ultrahigh energy cosmic rays in the Galaxy.; Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP); Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

‣ Antennas for the detection of radio emission pulses from cosmic-ray induced air showers at the Pierre Auger Observatory

Abreu, P.; Aglietta, M.; Ahlers, M.; Ahn, E. J.; Albuquerque, I. F. M.; Allard, D.; Allekotte, I.; Allen, J.; Allison, P.; Almela, A.; Alvarez Castillo, J.; Alvarez-Muniz, J.; Alves Batista, R.; Ambrosio, M.; Aminaei, A.; Anchordoqui, L.; Andringa, S.; An
Fonte: IOP Publishing Ltd; Bristol Publicador: IOP Publishing Ltd; Bristol
Tipo: Artigo de Revista Científica
Português
The Pierre Auger Observatory is exploring the potential of the radio detection technique to study extensive air showers induced by ultra-high energy cosmic rays. The Auger Engineering Radio Array (AERA) addresses both technological and scientific aspects of the radio technique. A first phase of AERA has been operating since September 2010 with detector stations observing radio signals at frequencies between 30 and 80 MHz. In this paper we present comparative studies to identify and optimize the antenna design for the final configuration of AERA consisting of 160 individual radio detector stations. The transient nature of the air shower signal requires a detailed description of the antenna sensor. As the ultra-wideband reception of pulses is not widely discussed in antenna literature, we review the relevant antenna characteristics and enhance theoretical considerations towards the impulse response of antennas including polarization effects and multiple signal reflections. On the basis of the vector effective length we study the transient response characteristics of three candidate antennas in the time domain. Observing the variation of the continuous galactic background intensity we rank the antennas with respect to the noise level added to the galactic signal.

‣ Description of atmospheric conditions at the Pierre Auger Observatory using the Global Data Assimilation System (GDAS)

Abreu, P.; Aglietta, M.; Ahlers, M.; Ahn, E. J.; Albuquerque, I. F. M.; Allard, D.; Allekotte, I.; Allen, J.; Allison, P.; Almela, A.; Alvarez Castillo, J.; Alvarez-Muniz, J.; Ambrosio, M.; Aminaei, A.; Anchordoqui, L.; Andringa, S.; Antici'c, T.; Aramo,
Fonte: Elsevier; Amsterdam Publicador: Elsevier; Amsterdam
Tipo: Artigo de Revista Científica
Português
Atmospheric conditions at the site of a cosmic ray observatory must be known for reconstructing observed extensive air showers. The Global Data Assimilation System (GDAS) is a global atmospheric model predicated on meteorological measurements and numerical weather predictions. GDAS provides altitude-dependent profiles of the main state variables of the atmosphere like temperature, pressure, and humidity. The original data and their application to the air shower reconstruction of the Pierre Auger Observatory are described. By comparisons with radiosonde and weather station measurements obtained on-site in Malargue and averaged monthly models, the utility of the GDAS data is shown. (C) 2012 Elsevier B.V. All rights reserved.; Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP); Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)