Nestmate Recognition in the Amazonian Myrmecophyte Ant Pseudomyrmex concolor Smith (Hymenoptera, Formicidae)

Nestmate recognition is fundamental to colonial cohesion in social insects, since it allows altruistic behavior towards relatives, recognition of intruders, territorial monopoly and resources defense. In ants, olfactory cues is a key factor in this process. Pseudomyrmex concolor is a highly aggressive ant that defends their host plant Tachigali myrmecophila against herbivores. However, this defense depends on the ant ability to discriminate in order to treat differentially between  members of their own colony and intruders . In this study we investigated “whether” and “how” P. concolor recognizes nestmates from non-nestmates. We hypothesized that P. concolor is skillful in recognizing nestmates and tested it in field with experiments using nestmates and non-nestmates. Additionally, to test the efficiency of resident ants against intraspecific competition during colony foundation, we simulate the plant occupation by a competitor queen, introducing non-nestmates queens in plants previously occupied by P. concolor. For the issue of the "how", we hypothesized that the main cue used by this ant in nestmate recognition is olfactory signal. Thus, we tested adaptive threshold model, which predicts that, if the individual odor and colony’s internal template are discrepant enough, the resident nestmate will behave aggressively towards incoming individuals. In this case, we confined nestmates with non-nestmates odors, and then, we reintroduced them in its host plants. In each experiment the frequency of aggressive behaviors were recorded and compared. Results showed that P. concolor recognize and discriminate nestmates from non-nestmates workers (biting and stinging them) and exclude potential competitors queens. Workers reintroduced in their own colony after impregnated with non-familiar odor were treated as non-nestmates. The adaptive threshold hypothesis was confirmed, the main cue used by this ant species in nestmate recognition is olfactory signals

Automatic generation and classification of test inputs

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2005.Includes bibliographical references (p. 51-54).This thesis describes a technique that selects, from a large set of test inputs, a small subset likely to reveal faults in the software under test. The technique takes a program or software component, plus a set of correct executions-say, from observations of the software running properly, or from an existing test suite that a user wishes to enhance. The technique first infers an operational model of the software's operation. Then, inputs whose operational pattern of execution differs from the model in specific ways are suggestive of faults. These inputs are further reduced by selecting only one input per operational pattern. The result is a small portion of the original inputs, deemed by the technique as most likely to reveal faults. Thus, the technique can also be seen as an error-detection technique. The thesis describes two additional techniques that complement test input selection. One is a technique for automatically producing an oracle (a set of assertions) for a test input from the operational model, thus transforming the test input into a test case. The other is a classification-guided test input generation technique that also makes use of operational models and patterns. When generating inputs, it filters out code sequences that are unlikely to contribute to legal inputs, improving the efficiency of its search for fault-revealing inputs.(cont.) We have implemented these techniques in the Eclat tool, which generates unit tests for Java classes. Eclat's input is a set of classes to test and an example program execution- say, a passing test suite. Eclat's output is a set of JUnit test cases, each containing a potentially fault-revealing input and a set of assertions at least one of which fails. In our experiments, Eclat successfully generated inputs that exposed fault-revealing behavior; we have used Eclat to reveal real errors in programs. The inputs it selects as fault-revealing are an order of magnitude as likely to reveal a fault as all generated inputs.by Carlos Pacheco.S.M

From linear to circular economy: The role of BS 8001:2017 for green transition in small business in developing economies

Implementing Circular Economy (CE) strategies has recently become one of the essential strategies for sustainable development and corporate social responsibility. However, despite the promising role and potential benefits of the CE for companies and society, there has still been insufficient analysis examining the challenges for circular transition faced by micro, small, and medium-sized enterprises (MSMEs) and the role that standards, such as British Standard (BS) 8001:2017, play during the transition process from linear to circular economy practices. Given this context and to further increase our understanding of the factors preventing the transition from linear to CE, this study aims to assess the CE implementation in MSMEs in developing economies in light of BS 8001:2017 through a survey with Brazilian MSMEs. The primary findings emphasize that CE practices from the Administration dimension occupied top positions in the ranking of implementation, along with one practice from the Innovation dimension. However, the results show that several practices associated with Transparency and Product Optimization in the value chain held the last level of evidence of implementation. Findings suggest that assessing MSMEs through BS 8001:2017 is beneficial for aiding them in analysing and reconsidering their practices related to the conventional linear business models of take-use-dispose. Collectively, the findings improve our understanding of the level of adoption of CE components implementation, the most and the least adopted practices during the CE transition. The study also provides implications for policy, theory, and practical applications in cases where there is an interest in assessing the maturity of CE implementation within MSMEs in developing economies

How age influences phonotaxis in virgin female Jamaican field crickets (Gryllus assimilis)

Female mating preference can be a dominant force shaping the evolution of sexual signals. However, females rarely have consistent mating preferences throughout their lives. Preference flexibility results fromcomplex interactions of predation risk, social and sexual experience, and age. Because residual reproductive value should theoretically decline with age, older females should not be as choosy as younger females. We explored how age influences phonotaxis towards a standard mate attraction signal using a spherical treadmill (trackball) and a no-choice experimental protocol. Female Jamaican field crickets, Gryllus assimilis, were highly variable in their phonotaxis; age explained up to 64% of this variation. Females 10 days post imaginal eclosion and older oriented toward the mate attraction signal, with 10-and 13-day females exhibiting the greatest movement in the direction of the signal. Our study suggests 10-and 13-day old females would be most responsive when quantifying the preference landscape for G. assimilis sexual signals

Indirect search for dark matter: prospects for GLAST

Possible indirect detection of neutralino, through its gamma-ray annihilation product, by the forthcoming GLAST satellite from our galactic halo, M31, M87 and the dwarf galaxies Draco and Sagittarius is studied. Gamma-ray fluxes are evaluated for the two representative energy thresholds, 0.1 GeV and 1.0 GeV, at which the spatial resolution of GLAST varies considerably. Apart from dwarfs which are described either by a modified Plummer profile or by a tidally-truncated King profiles, fluxes are compared for halos with central cusps and cores. It is demonstrated that substructures, irrespective of their profiles, enhance the gamma-ray emission only marginally. The expected gamma-ray intensity above 1 GeV at high galactic latitudes is consistent with the residual emission derived from EGRET data if the density profile has a central core and the neutralino mass is less than 50 GeV, whereas for a central cusp only a substantial enhancement would explain the observations. From M31, the flux can be detected above 0.1 GeV and 1.0 GeV by GLAST only if the neutralino mass is below 300 GeV and if the density profile has a central cusp, case in which a significant boost in the gamma-ray emission is produced by the central black hole. For Sagittarius, the flux above 0.1 GeV is detectable by GLAST provided the neutralino mass is below 50 GeV. From M87 and Draco the fluxes are always below the sensitivity limit of GLAST.Comment: 14 Pages, 7 Figures, 3 Tables, version to appear on Physical Review

Electromagnetic-field quantization and spontaneous decay in left-handed media

We present a quantization scheme for the electromagnetic field interacting with atomic systems in the presence of dispersing and absorbing magnetodielectric media, including left-handed material having negative real part of the refractive index. The theory is applied to the spontaneous decay of a two-level atom at the center of a spherical free-space cavity surrounded by magnetodielectric matter of overlapping band-gap zones. Results for both big and small cavities are presented, and the problem of local-field corrections within the real-cavity model is addressed.Comment: 15 pages, 5 figures, RevTe

A cell surface arabinogalactan-peptide influences root hair cell fate

Indexación: Scopus.Root hairs (RHs) develop from specialized epidermal trichoblast cells, whereas epidermal cells that lack RHs are known as atrichoblasts. The mechanism controlling RH cell fate is only partially understood. RH cell fate is regulated by a transcription factor complex that promotes the expression of the homeodomain protein GLABRA 2 (GL2), which blocks RH development by inhibiting ROOT HAIR DEFECTIVE 6 (RHD6). Suppression of GL2 expression activates RHD6, a series of downstream TFs including ROOT HAIR DEFECTIVE 6 LIKE-4 (RSL4) and their target genes, and causes epidermal cells to develop into RHs. Brassinosteroids (BRs) influence RH cell fate. In the absence of BRs, phosphorylated BIN2 (a Type-II GSK3-like kinase) inhibits a protein complex that regulates GL2 expression. Perturbation of the arabinogalactan peptide (AGP21) in Arabidopsis thaliana triggers aberrant RH development, similar to that observed in plants with defective BR signaling. We reveal that an O-glycosylated AGP21 peptide, which is positively regulated by BZR1, a transcription factor activated by BR signaling, affects RH cell fate by altering GL2 expression in a BIN2-dependent manner. Changes in cell surface AGP disrupts BR responses and inhibits the downstream effect of BIN2 on the RH repressor GL2 in root epidermis. © 2020 The Authors. New Phytologist © 2020 New Phytologist Trusthttps://nph-onlinelibrary-wiley-com.recursosbiblioteca.unab.cl/doi/10.1111/nph.1648