First measurement of π-e→π-eγ pion virtual compton scattering

Pion virtual compton scattering (VCS) via the reaction π-e→π-eγ was observed in the Fermilab E781 SELEX experiment. SELEX used a 600 GeV/c π- beam incident on target atomic electrons, detecting the incident π- and the final state π-, electron and γ. Theoretical predictions based on chiral perturbation theory are incorporated into a Monte Carlo simulation of the experiment and are compared to the data. The number of reconstructed events (=9) and their distribution with respect to the kinematic variables (for the kinematic region studied) are in reasonable accord with the predictions. The corresponding π- VCS experimental cross section is σ=38.8±13 nb, in agreement with the theoretical expectation of σ=34.7 nb.

Little cicada of sugarcane Mahanarva posticata (Homoptera: Cercopidae). A Brazilian agricultural pest. Morpho-histological study of salivary glands

Little cicadas are homopteran insect pests of sugarcane plantations. As these insects suck out the sap from the leaf parenchyma, they inoculate a toxic saliva that damages the plant vessels, thus promoting the loss of glucose by the affected plant. The morphological and histological analyses of the salivary glands of the little cicada Mahanarva posticata, revealed that these glands are formed by 2 portions: one portion comprises a group of acini and has been denominated as the principal gland; the second portion is filamentous in nature and has been denominated as the accessory gland; it is formed by very long and fine filaments. The acinous portion of the gland can be subdivided into 2 lobes: an anterior lobe formed by 3 lobules (I, II, III), and a posterior lobe formed by lobule IV and the excretory duct. Histologically, the salivary glands showed that the filaments are empty sutructures composed by several internal channels with secretion granules being observed in the cytoplasm of the cells of the secretory filaments. Lobules I and II of the principal gland are characterized by being highly basophilic and for accumulating a large amount of secretion in both the cytoplasm of the cells and inside secretion vesicles. Histochemically, we verified that the secretion produced by these glands is lipidic and protein in nature, with the production of polysaccharides being very low. The differences in stain and appearance of the different regions of the salivary gland lead us to believe that the final glandular product is lipoproteic in nature.

Double Higgs production at the LHC as a robust test of little Higgs models

We analyze double Higgs boson production at the LHC in the context of Little Higgs models. In double Higgs production, the diagrams involved are directly related to those that cause the cancellation of the quadratic divergence of the Higgs self-energy, so this mode provides a robust prediction for this class of models. We find that in extensions of this model with the inclusion of a so-called T-parity, there is a significant enhancement in the cross sections as compared to the Standard Model. © 2006 American Institute of Physics.

Double Higgs production and quadratic divergence cancellation in little Higgs models with T-parity

We analyze double Higgs boson production at the Large Hadron Collider in the context of Little Higgs models. In double Higgs production, the diagrams involved are directly related to those that cause the cancellation of the quadratic divergence of the Higgs self-energy, providing a robust prediction for this class of models. We find that in extensions of this model with the inclusion of a so-called T-parity, there is a significant enhancement in the cross sections as compared to the Standard Model. © SISSA 2006.

The behavior and natural history of Chartergellus, a little-known genus of neotropical social wasps (Vespidae Polistinae Epiponini)

This study reviews published data on the behavior and natural history of Chartergellus and presents the first observations on social interactions in this genus of tropical swarm-founding wasps. Observations of Chartergellus golfitensis in Costa Rica and C. punctatior in Colombia showed that queens perform a post-oviposition egg-guarding vigil, and a bending display like that characteristic of epiponine social wasps that lack consistent morphological differences between workers and queens and have caste determination in the adult stage. Young, old, and queen (egg-laying) females of C. golfitensis showed small differences that indicate color changes with age, and structural differences that could be due to seasonal or colony-cycle changes in developmental conditions, but do not rule out the possibility of pre-adult caste determination, a phenomenon that needs to be carefully distinguished from pre-adult caste bias. Sexual dimorphism and the behavior of males at the nest in C. golfitensis is described, as well as the aggressive and avoidance behavior of females toward males. Nest structure in both species is as described previously for Chartergellus species, but some anomalies and their possible evolutionary significance are discussed. Cell initiation by an egg-laying queen, a behavior never seen by workers, and by a young female with slightly developed ovaries, may be vestiges of ancestral solitary reproductive traits where developed ovaries are associated with cell construction. © 2010 Dipartimento di Biologia Evoluzionistica dell'Università, Firenze, Italia.

Meniscal mineralisation in little spotted cats

Background: The aim of this study was to evaluate the stifle joints of little spotted cats in captivity using radiographic and CT studies. The hypothesis was that these animals would have meniscal mineralisation that could be detectable by imaging studies. Twelve intact little spotted cats (Leopardus tigrinus), 2 females and 10 males, aged from 1.5 to 11.11 years old and weighing 1.9-3.05 kg were studied. These animals, which were living in the Quinzinho de Barros Municipal Zoo, had no symptoms or known disease processes at the time of the study. The plain radiographs and computed tomography (CT) scans of both stifle joints were performed under general anaesthesia. Sequential transverse images were acquired on a spiral scanner.Results: No signs of articular disease were observed in any of the animals. Radiographically, the meniscal mineralisation was detected as an oval radiopacity in the cranial compartment on the mediolateral projection, located within the area of the medial meniscus. On craniocaudal projection, the mineralisation was more difficult to visualise. In one of the animals, it was not possible to identify the meniscal mineralisation in either of the stifle joints. Using CT, meniscal mineralisation was best identified in the transverse plane images.Conclusions: Meniscal mineralisation appears to be a normal anatomic feature in little spotted cats. © 2013 Rahal et al.; licensee BioMed Central Ltd.

Some deviations of form: a little essay on psychoanalysis, art and aesthetics

This work intends to investigate the use of psychoanalytical theory within the aesthetic and critical contemporary art field. To this purpose, it focuses on two philosophers who have become significant in our time: the art critic Hal Foster and the art historian Georges Didi-Huberman. This study aims to show how far the concepts generated in psychoanalytic praxis allowed interpretations that disrupt the traditional aesthetics field. This type of analysis is possible once we abandon the paradigm of “applied psychoanalysis”, which is still current in non-clinical setting. Finally, the proposal wants to argue that the category of the amorphous may clarify certain aesthetic experiences that range from the modernity of art through postmodernity.

Breeding season diet of Scarlet Ibises and Little Blue Herons in a Brazilian mangrove swamp

We studied the diet composition and overlap of Scarlet Ibises (Eudocimus ruber) and Little Blue Herons (Egretta caerulea in a mangrove swamp in southeast Brazil during the 1996-1997 breeding season, which occurs during the rainiest period. Crabs comprised 95% of all prey taken by the ibises and 80% of the prey of the herons, Nevertheless, diet overlap was small (similar to 30%) due to ibises feeding mostly on Uca spp. and Eurythium limosum crabs, which were taken from their burrows; the herons fed on the arboreal and semi-arboreal Aratus Pisonii and Metasesarma rubripes crabs. Divergent hunting strategies of ibises (tactile foragers) and herons visually-oriented predators) explains the diet segregation when preying on an ecologically diverse crab guild, but it is unclear why herons prey rarely on fiddler crabs. Scarlet Ibises bred successfully while feeding oil estuarine organisms living in low salinities in the mangroves, showing that mangroves may be adequate foraging habitats for chick-rearing ibises during periods of low salinity.

Evidence for Millennial-Scale Climate Change During Marine Isotope Stages 2 and 3 at Little Lake, Western Oregon, U.S.A.

Pollen and geochemical data from Little Lake, western Oregon, suggest several patterns of millennial-scale environmental change during marine isotope stage (MIS) 2 (14,100–27,600 cal yr B.P.) and the latter part of MIS 3 (27,600–42,500 cal yr B.P.). During MIS 3, a series of transitions between warm- and cold-adapted taxa indicate that temperatures oscillated by ca. 2±–4±C every 1000–3000 yr. Highs and lows in summer insolation during MIS 3 are generally associated with the warmest and coldest intervals. Warm periods at Little Lake correlate with warm sea-surface temperatures in the Santa Barbara Basin. Changes in the strength of the subtropical high and the jet stream may account for synchronous changes at the two sites. During MIS 2, shifts between mesic and xeric subalpine forests suggest changes in precipitation every 1000–3000 yr. Increases in Tsuga heterophylla pollen at 25,000 and 22,000 cal yr B.P. imply brief warmings. Minimum summer insolation and maximum global ice-volumes during MIS 2 correspond to cold and dry conditions. Fluctuations in precipitation at Little Lake do not correlate with changes in the Santa Barbara Basin and may be explained by variations in the strength of the glacial anticyclone and the position of the jet stream.

Range extensions and conservation of some threatened or little known Brazilian grassland birds

Populations of grassland birds are declining in Brazil due to profound alterations to grassland habitats. In this paper, we present recent records and range extensions for 12 threatened or little known Brazilian grassland species: Ocellated Crake Micropygia schomburgkii, Sickle-winged Nightjar Eleothreptus anomalus, Campo Miner Geositta poeciloptera, Rufous-sided Pygmytyrant Euscarthmus rufomarginatus, Sharp-tailed Grass-tyrant Culicivora caudacuta, Cocktailed Tyrant Alectrurus tricolor, Cinereous Warbling-finch Poospiza cinerea, Black-masked Finch Coryphaspiza melanotis, Tawny-bellied Seedeater Sporophila hypoxantha, Marsh Seedeater S. palustris, Chestnut Seedeater S. cinnamomea and Black-bellied Seedeater S. melanogaster. We also comment on the biogeography and conservation of these species.

A graphical tool for an analytical approach of scattering photons by the Compton effect

The photons scattered by the Compton effect can be used to characterize the physical properties of a given sample due to the influence that the electron density exerts on the number of scattered photons. However, scattering measurements involve experimental and physical factors that must be carefully analyzed to predict uncertainty in the detection of Compton photons. This paper presents a method for the optimization of the geometrical parameters of an experimental arrangement for Compton scattering analysis, based on its relations with the energy and incident flux of the X-ray photons. In addition, the tool enables the statistical analysis of the information displayed and includes the coefficient of variation (CV) measurement for a comparative evaluation of the physical parameters of the model established for the simulation. (C) 2012 Elsevier B.V. All rights reserved.

Study of electron densities of normal and neoplastic human breast tissues by Compton scattering using synchrotron radiation

Electron densities of 33 samples of normal (adipose and fibroglangular) and neoplastic (benign and malignant) human breast tissues were determined through Compton scattering data using a mono-chromatic synchrotron radiation source and an energy dispersive detector. The area of Compton peaks was used to determine the electron densities of the samples. Adipose tissue exhibits the lowest values of electron density whereas malignant tissue the highest. The relationship with their histology was discussed. Comparison with previous results showed differences smaller than 4%. (C) 2012 Elsevier Ltd. All rights reserved.

Compton scattering spectrum as a source of information of normal and neoplastic breast tissues' composition

In this work we measured X-ray scatter spectra from normal and neoplastic breast tissues using photon energy of 17.44 key and a scattering angle of 90 degrees, in order to study the shape (FWHM) of the Compton peaks. The obtained results for FWHM were discussed in terms of composition and histological characteristics of each tissue type. The statistical analysis shows that the distribution of FWHM of normal adipose breast tissue clearly differs from all other investigated tissues. Comparison between experimental values of FWHM and effective atomic number revealed a strong correlation between them, showing that the FWHM values can be used to provide information about elemental composition of the tissues. (C) 2012 Elsevier Ltd. All rights reserved.

Growth hormone response to growth hormone-releasing peptide-2 in growth hormone-deficient Little mice

OBJECTIVE: To investigate a possible direct, growth hormone-releasing, hormone-independent action of a growth hormone secretagogue, GHRP-2, in pituitary somatotroph cells in the presence of inactive growth hormone-releasing hormone receptors. MATERIALS AND METHODS: The responses of serum growth hormone to acutely injected growth hormone-releasing P-2 in lit/litmice, which represent a model of GH deficiency arising frommutated growth hormone-releasing hormone-receptors, were compared to those observed in the heterozygous (lit/+) littermates and wild-type (+/+) C57BL/6J mice. RESULTS: After the administration of 10 mcg of growth hormone-releasing P-2 to lit/lit mice, a growth hormone release of 9.3 +/- 1.5 ng/ml was observed compared with 1.04 +/- 1.15 ng/ml in controls (p<0.001). In comparison, an intermediate growth hormone release of 34.5 +/- 9.7 ng/ml and a higher growth hormone release of 163 +/- 46 ng/ml were induced in the lit/+ mice and wild-type mice, respectively. Thus, GHRP-2 stimulated growth hormone in the lit/lit mice, and the release of growth hormone in vivo may be only partially dependent on growth hormone-releasing hormone. Additionally, the plasma leptin and ghrelin levels were evaluated in the lit/lit mice under basal and stimulated conditions. CONCLUSIONS: Here, we have demonstrated that lit/lit mice, which harbor a germline mutation in the Growth hormone-releasing hormone gene, maintain a limited but statistically significant growth hormone elevation after exogenous stimulation with GHRP-2. The present data probably reflect a direct, growth hormone-independent effect on Growth hormone S (ghrelin) stimulation in the remaining pituitary somatotrophs of little mice that is mediated by growth hormone S-R 1a.