TEMPORAL DYNAMICS IN PANTANAL HUMMINGBIRD ASSEMBLAGES IS TRIGGERED BY FLOOD PULSE

Abstract ∙ Hummingbirds (Trochilidae) are highly specialized New World birds that depend on nectar as their major food source. In response to seasonal food limitations, many trochilids develop dispersal and long-distance migration patterns, but these patterns are understudied for many continental South American species. In this study, conducted in the Brazilian Pantanal, we investigated the movement patterns of hummingbirds in a highly variable environment, where an annual flood pulse leads to four distinctive seasonal periods (high water, receding water, dry period, and rising water). Our objective was to verify how these four periods affected the hummingbird community according to habitat occupation in savannas or forests. This study was conducted in the northeastern Pantanal of Mato Grosso, Brazil (16° 39'S, 56°47'W, 119–131 m a.s.l.), covering two annual inundation periods (2014–2016). Data were collected using mist net sampling. Two migrant and seven resident species were identified. The results indicated significant differences in hummingbird species richness and abundance between habitats; savanna habitats were the richest habitats during rainy seasons (rising and high water). Higher hummingbird abundance in these seasonal periods was seemingly related to higher food availability since these seasons corresponded to the main flowering period of ornithophilous plants and other angiosperms

Nuclear like effects in proton-proton collisions at high energy

We show that several effects considered nuclear effects are not nuclear in the sense that they do not only occur in nucleus-nucleus and hadron-nucleus collisions but, as well, they are present in hadron-hadron (proton-proton) collisions. The matter creation mechanism in hh, hA and AA collisions is always the same. The pT suppression of particles produced in large multiplicity events compared to low multiplicity events, the elliptic flow and the Cronin effect are predicted to occur in pp collisions at LHC energies as a consequence of the obtained high density partonic medium

Infanticide in Chimpanzees: Taphonomic Case Studies from Gombe

Objectives We present a study of skeletal damage to four chimpanzee (Pan troglodytes) infanticide victims from Gombe National Park, Tanzania. Skeletal analysis may provide insight into the adaptive significance of infanticide by examining whether nutritional benefits sufficiently explain infanticidal behavior. The nutritional hypothesis would be supported if bone survivorship rates and skeletal damage patterns are comparable to those of monkey prey. If not, other explanations, such as the resource competition hypothesis, should be considered. Methods Taphonomic assessment of two chimpanzee infants included description of breakage and surface modification, data on MNE, %MNE, and bone survivorship. Two additional infants were assessed qualitatively. The data were compared to published information on monkey prey. We also undertook a review of published infanticide cases. Results The cases were intercommunity infanticides (one male and three female infants) committed by males. Attackers partially consumed two of the victims. Damage to all four infants included puncture marks and compression fractures to the cranium, crenulated breaks to long bones, and incipient fractures on ribs. Compared to monkey prey, the chimpanzee infants had an abundance of vertebrae and hand/foot bones. Conclusions The cases described here suggest that chimpanzees may not always completely consume infanticide victims, while reports on chimpanzee predation indicated that complete consumption of monkey prey usually occurred. Infanticidal chimpanzees undoubtedly gain nutritional benefits when they consume dead infants, but this benefit may not sufficiently explain infanticide in this species. Continued study of infanticidal and hunting behavior, including skeletal analysis, is likely to be of interest

Particle production azimuthal asymmetries in a clustering of color sources model

The collective interactions of many partons in the first stage of the collisions is the usual accepted explanation of the sizable elliptical flow. The clustering of color sources provides a framework of partonic interactions. In this scheme, we show a reasonable agreement with RHIC data for pT<1.5 GeV/c in both the dependence of v2 transverse momentum and in the shape of the nuclear modified factor on the azimuthal angle for different centralities. We show the predictions at LHC energies for Pb-Pb. In the case of proton-proton collisions a sizable v2 is obtained at this energy.Comment: To appear in Journal of Physics

Universal behavior of baryons and mesons' transverse momentum distributions in the framework of percolation of strings

In the framework of percolation of strings, we present predictions for the $R_{AA}$ and $R_{CP}$ for mesons and baryons and for $\bar{p}/\pi^{0}$ ratios at LHC energies.Comment: Presented at "Heavy Ion Collisions at the LHC: last call for predictions", Geneva Switzerland, May 14th-June 8t

Investigation of high pt_{t} events in Nucleus-Nucleus collisions using the Hijing event generator

In recent years lot of interest has been observed in the nucleus-nucleus collisions at RHIC energies in phenomena related to high $p_{t}$ physics \cite{ref1}. The suppression of high $p_{t}$ particles and disappearance of back-to-back jets compared to the scaling with number of binary nucleon-nucleon collisions indicates that a nearly perfect liquid is produced in these collisions. Results on self shadowing of high $p_{t}$ events are presented using hadron multiplicity associated to high $p_{t}$ and unbiased events in nucleus-nucleus collisions \cite{ref2} obtained from the hijing event generator.Comment: 4 pages, 3 figures, Proceedings of the poster presented at Quark Matter 200

Percolation of strings and the first RHIC data on multiplicity and tranverse momentum distributions

The dependence of the multiplicity on the number of collisions and the transverse momentum distribution for central and peripheral Au-Au collisions are studied in the model of percolation of strings relative to the experimental conditions at RHIC. The comparison with the first RHIC data shows a good agreement.Comment: RevTeX, 11 pages, 4 eps figures included using epsfi

Factorial Moments in a Generalized Lattice Gas Model

We construct a simple multicomponent lattice gas model in one dimension in which each site can either be empty or occupied by at most one particle of any one of $D$ species. Particles interact with a nearest neighbor interaction which depends on the species involved. This model is capable of reproducing the relations between factorial moments observed in high--energy scattering experiments for moderate values of $D$. The factorial moments of the negative binomial distribution can be obtained exactly in the limit as $D$ becomes large, and two suitable prescriptions involving randomly drawn nearest neighbor interactions are given. These results indicate the need for considerable care in any attempt to extract information regarding possible critical phenomena from empirical factorial moments.Comment: 15 pages + 1 figure (appended as postscript file), REVTEX 3.0, NORDITA preprint 93/4