Unique Derived Features in Spermiogenesis and Sperm Morphology Supporting a Close Relationship between the Species of Hollandichthys and Rachoviscus (Characiformes: Characidae)

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Colony defensive behavior by the social wasp Polybia (Trichothorax) sericea (Hymenoptera, Vespidae)

This work aimed at evaluating the aggressive response of Polybia sericea, incited by mechanical means, as well as collecting information on the biological and population parameters of this species in Caatinga environments. There were positive correlations (P < 0.05) between the number of aggressors and the number of eggs, larvae and adults present in the nests. These results showed that the magnitude of the defense response exhibited by P. sericea is proportional to the energetic investment carried out by the colony in making young forms. The positive significant correlation between the number of aggressors and the total number of adults of the colony corroborates the hypothesis that colonies with a large population of adults have greater potential to perform what is called defensive altruism.

Quantitative aspects of entanglement in the driven Jaynes-Cummings model

Adopting the framework of the Jaynes-Cummings model with an external quantum field, we obtain exact analytical expressions of the normally ordered moments for any kind of cavity and driving fields. Such analytical results are expressed in the integral form, with their integrands having a commom term that describes the product of the Glauber-Sudarshan quasiprobability distribution functions for each field, and a kernel responsible for the entanglement. Considering a specific initial state of the tripartite system, the normally ordered moments are then applied to investigate not only the squeezing effect and the nonlocal correlation measure based on the total variance of a pair of Einstein-Podolsky-Rosen type operators for continuous variable systems, but also the Shchukin-Vogel criterion. This kind of numerical investigation constitutes the first quantitative characterization of the entanglement properties for the driven Jaynes-Cummings model.

Synaptonemal polycomplexes in spermatids: a characteristic trait of Orthoptera?

Spermatogenesis was analysed in a cricket, Eneoptera surinamensis (Gryllidae, Orthoptera), using ultrathin serial sections and transmission electron microscopy. Special attention was placed on documentation of the development and structure of synaptonemal polycomplexes (PCs) within spermatid nuclei. Pachytene spermatocytes showed the usual tripartite synaptonemal complexes in the nuclear lumen. PCs were situated close to chromosomes at the periphery of spindles in prometaphase I spermatocytes, where microtubule density was low. The PCs are probably incorporated into the daughter nuclei of both meiotic divisions by adhesion to chromosomes. Finally, PCs end up within spermatid nuclei. Analysis of serial sections through three nuclei of young spermatids revealed at least one PC within each. The PCs were intimately attached to an electrondense spherical nuclear body. This topographical correlation was confirmed through inspection of random sections. The PCs may have an affinity to the spherical bodies. In more developed spermatids, PCs and nuclear bodies were missing. Disassembly products of the PCs may play a role in spermatid maturation. In a series of other Orthoptera species, PCs have been reported to occur in the cytoplasm or the nuclei of spermatids. In most other systematic groups, PCs do not form at all or disassemble earlier. The presence of PCs in young spermatids, therefore, seems to be typical of Orthoptera.

Astrocytes and human cognition: Modeling information integration and modulation of neuronal activity

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Selective Ablation of the Androgen Receptor in Mouse Sertoli Cells Affects Sertoli Cell Maturation, Barrier Formation and Cytoskeletal Development

The observation that mice with a selective ablation of the androgen receptor (AR) in Sertoli cells (SC) (SCARKO mice) display a complete block in meiosis supports the contention that SC play a pivotal role in the control of germ cell development by androgens. To delineate the physiological and molecular mechanism responsible for this control, we compared tubular development in pubertal SCARKO mice and littermate controls. Particular attention was paid to differences in SC maturation, SC barrier formation and cytoskeletal organization and to the molecular mediators potentially involved. Functional analysis of SC barrier development by hypertonic perfusion and lanthanum permeation techniques and immunohistochemical analysis of junction formation showed that SCARKO mice still attempt to produce a barrier separating basal and adluminal compartment but that barrier formation is delayed and defective. Defective barrier formation was accompanied by disturbances in SC nuclear maturation (immature shape, absence of prominent, tripartite nucleoli) and SC polarization (aberrant positioning of SC nuclei and cytoskeletal elements such as vimentin). Quantitative RT-PCR was used to study the transcript levels of genes potentially related to the described phenomena between day 8 and 35. Differences in the expression of SC genes known to play a role in junction formation could be shown from day 8 for Cldn11, from day 15 for Cldn3 and Espn, from day 20 for Cdh2 and Jam3 and from day 35 for ZO-1. Marked differences were also noted in the transcript levels of several genes that are also related to cell adhesion and cytoskeletal dynamics but that have not yet been studied in SC (Actn3, Ank3, Anxa9, Scin, Emb, Mpzl2). It is concluded that absence of a functional AR in SC impedes the remodeling of testicular tubules expected at the onset of spermatogenesis and interferes with the creation of the specific environment needed for germ cell development.

The effect of plant diversity on fungus garden development and foraging behavior of leaf-cutting ants (Hymenoptera: Formicidae)

The leaf-cutting ants forage a wide variety of plant species, used for symbiotic fungus cultivation. To better understand this tripartite complex interaction, 24 colonies of Acromyrmex subterraneus brunneus were conditioned for 4 months to 6 different plants (Citrus spp., Ligustrum spp., Acalypha spp., Eucalyptus spp., Alchornea triplinervia, Melia spp.), to verify the influence of conditioning on foraging behavior of workers. The effect of plants on symbiotic fungus development was studied separately, through macerated plants in Agar and culture medium A as the control. During foraging, workers presented polyphagic foraging behavior, refusing the plants to which they were conditioned. The selection of plants is not correlated with the plant substrate that promotes good development of symbiotic fungus. Such results demonstrate the importance of plant diversity for fungus garden maintenance.

A new interpretation of the defense glands of neotropical Ruptitermes (Isoptera, Termitidae, Apicotermitinae)

Suicidal altruism has been reported for some species of eusocial insects, in which the individual dies in defense of the society. The termites of the genus Ruptitermes are known for the suicidal behavior of the workers which liberate a sticky defensive secretion by body bursting. In the present paper it is given a new interpretation of the defense glands of Neotropical Ruptitermes based on the morphological analysis of three species collected at Rio Claro, SP, Brazil. Before the current study, the suicidal defensive behavior was attributed to the dehiscence of the salivary gland reservoirs. The defense or dehiscent glands of Neotropical Ruptitermes are pair structures rounded in shape that are independent of the salivary glands. The dehiscent glands consist of multiple secretory units that are kept together by thin connective tissue. Each secretory unit is composed of one cell generally with one peripheral nucleus and characteristic secretion. The three species studied here present some histological differences in the secretory units, probably related to the chemical composition of the secretion.

The United States and Latin America and the Caribbean: Highlights of economics and trade

Foreword by Alicia Bárcena

Innovating, gaining market share and fostering social inclusion: success stories in SME development

Includes bibliography

Barbados: public-private sector partnership

Includes bibliography

Recent advances in brain physiology and cognitive processing

The discovery of participation of astrocytes as active elements in glutamatergic tripartite synapses (composed by functional units of two neurons and one astrocyte) has led to the construction of models of cognitive functioning in the human brain, focusing on associative learning, sensory integration, conscious processing and memory formation/retrieval. We have modelled human cognitive functions by means of an ensemble of functional units (tripartite synapses) connected by gap junctions that link distributed astrocytes, allowing the formation of intra- and intercellular calcium waves that putatively mediate large-scale cognitive information processing. The model contains a diagram of molecular mechanisms present in tripartite synapses and contributes to explain the physiological bases of cognitive functions. It can be potentially expanded to explain emotional functions and psychiatric phenomena. © MSM 2011.

Um olhar semiótico sobre o processo de indexação: a questão da representação e do referente

The indexing process is determined the subject of the document and its relation with the representation information. To cultivate the interdisciplinary contributions is essential, especially when the relationship allows substantial additions to the area of research. Rehearse some contributions in this article of Semiotics of Charles Sanders Peirce in the field of study of the indexing process, in particular, the notions of representation and referent. It is concluded that the tripartite division of the sign provides basis for to understanding the process of thematic representation, discussing the relationship of the sign with the object and the phenomenon presented, in the indexer sees the documentary language as referent.

Gaps in the welfare State and reforms to pension systems in Latin America

Includes bibliography

Why entanglement of formation is not generally monogamous

Unlike correlation of classical systems, entanglement of quantum systems cannot be distributed at will: if one system A is maximally entangled with another system B, it cannot be entangled at all with a third system C. This concept, known as the monogamy of entanglement, is manifest when the entanglement of A with a pair BC can be divided as contributions of the entanglement between A and B and A and C, plus a term τABC involving genuine tripartite entanglement and so expected to be always positive. A very important measure in quantum information theory, the entanglement of formation (EOF), fails to satisfy this last requirement. Here we present the reasons for that and show a set of conditions that an arbitrary pure tripartite state must satisfy for the EOF to become a monogamous measure, i.e., for τABC≥0. The relation derived is connected to the discrepancy between quantum and classical correlations, τABC being negative whenever the quantum correlation prevails over the classical one. This result is employed to elucidate features of the distribution of entanglement during a dynamical evolution. It also helps to relate all monogamous instances of the EOF to the squashed sntanglement, an entanglement measure that is always monogamous. © 2013 American Physical Society.