Social animals are faced with an intriguing dilemma. On the one hand, interactions between individuals are essential to exchange information and to promote cohesion, while on the other hand such ...interactions carry with them the risk of catching and transmitting parasites. This trade-off is particularly significant for social insects because low within-colony genetic diversity makes their colonies potentially vulnerable to parasites while frequent interactions are essential to the development of the colonial odor profile necessary for nestmate recognition. Here we investigate whether social interactions between young and old leaf-cutting ant workers show evidence of this trade-off. We find that old workers engage in more selfgrooming and mandibular scraping than young workers, both in keeping with old workers having been more exposed to parasites. In contrast, we find that young workers engaged in more allogrooming than old workers, which seems likely to have a different motivation possibly the transfer of recognition cues. Furthermore, young workers tended to engage in allogrooming with other young workers, although it was the old workers that were most active and with whom allogrooming would seem likely to optimize information or chemicals transfer. This suggests that young workers may be attempting to minimize the risk of parasite transmission during their social interactions. Although limited to behavioral data, these results hint that ant workers may be sensitive to the trade-off between the transmission of recognition cues and disease, and adjust their social interactions accordingly.
In recent years the usage of machine learning techniques within data-intensive sciences in general and high-energy physics in particular has rapidly increased, in part due to the availability of ...large datasets on which such algorithms can be trained, as well as suitable hardware, such as graphic or tensor processing units, which greatly accelerate the training and execution of such algorithms. Within the HEP domain, the development of these techniques has so far relied on resources external to the primary computing infrastructure of the WLCG (Worldwide LHC Computing Grid). In this paper we present an integration of hardware-accelerated workloads into the Grid through the declaration of dedicated queues with access to hardware accelerators and the use of Linux container images holding a modern data science software stack. A frequent use-case in the development of machine learning algorithms is the optimization of neural networks through the tuning of their Hyper Parameters (HP). For this often a large range of network variations must be trained and compared, which for some optimization schemes can be performed in parallel - a workload well suited for Grid computing. An example of such a hyper-parameter scan on Grid resources for the case of flavor tagging within ATLAS is presented.
The Polycyclic aromatic hydrocarbons PAHs (naphthalene, acenaphthylene, acenaphthene, phenanthrene, fluoranthene, pyrene, benzo(a)anthracene, chrysene, benzo(b)fluoranthene, benzo(k)fluoranthene, ...benzo(a)pyrene, indeno(1,2,3-cd)pyrene and benzo(ghi)perylene) concentrations in fine (PM
2.5) and coarse (PM
2.5–10) atmospheric particulate matter were measured at São Paulo city, Brazil. The dominant PAH compounds were indeno(1,2,3-cd)pyrene, benzo(ghi)perylene and benzo(b)fluoranthene for both the fractions. The calculated ratios of some specific PAHs were in close agreement with those attributed to direct emissions of car exhaust. The factor analysis for PM
2.5 produced four factors: Factor 1 was attributed to diesel emissions, Factor 2 was attributed to stationary combustion source, Factor 3 was attributed to vehicular emissions and Factor 4 to natural gas combustion and biomass burning. For PM
2.5–10, Factor 1 was attributed to vehicular emissions and Factor 2 was attributed to a mixture of combustion sources such as natural gas combustion, incineration emissions and oil combustion. Also, vehicular emissions were assumed to be the major source of PAHs in the São Paulo city atmosphere.
Mercury (Hg total) fluxes were calculated for rainwater, throughfall and stream water in a small catchment located in the northeastern region of the Brazilian Amazon (Serra do Navio, Amapá State), ...whose upper part is covered by a natural rainforest and lower part was altered due to deforestation and activities related to manganese mining. The catchment area is 200 km from the nearest gold mining (garimpo). Minimum and maximum Hg concentrations were measured monthly from October 1996 to September 1997 and were 3.5–23.4 ng l
−1 for rainwater, 16.5–82.7 ng l
−1 for throughfall (March–August 1997) and 1.2–6.1 and 4.2–18.8 ng l
−1 for stream water, in natural and disturbed areas, respectively. In the natural area, the inputs were 18.2 μg m
−2 year
−1 in rainwater and 72 μg m
−2 year
−1 in throughfall. This enrichment was attributed to dry deposition. The stream output of 2.9 μg m
−2 year
−1 indicates that Hg is being recycled within the forest as other chemical species or is being retained by the soil system, as confirmed by the cumulative Hg burden in the 0–10 cm surface layer, which was 36
480 μg m
−2. When the disturbed area of the catchment was included, the stream output was 9.3 μg m
−2, clearly indicating the impact of the deforestation of the lower part of the basin on the release of mercury. The Hg burden in the disturbed area was 7560 μg m
−2 for the 0–10 cm surface layer.
This paper presents a parametric study of symmetrically loaded multiplanar KK connections in circular hollow steel sections. The connections were designed with gaps between the diagonal braces. ...Analyses were performed using the commercial finite element program Ansys. A total of 54 KK connections and their corresponding uniplanar K connections were analyzed and compared in terms of the connection resistance. A new objective criterion to assess the two failure modes most often occurring in KK connections is proposed. Failure mode 1 is observed when two neighboring diagonal braces loaded in the same sense act as one brace penetrating the chord together. In failure mode 2, excessive deformation is observed in the chord region between two neighboring braces, folding the chord wall. However, in some cases, the failure mode is not easily identified, or both failure types are present. The proposed criterion is based on the diametric deformation of the chord and objectively assesses the failure mode. By comparing the connection resistance of KK and K connections as determined using numerical analyses, analytical expressions to predict the connection resistance of KK connections were developed. The expressions accurately predict the connection resistance based on geometric parameters and the resistance of the corresponding uniplanar K connection.
•We present a parametric study of multiplanar KK connections in circular HSS.•We assess the numerical methodology adopted indicating its limits of application.•We compare more than 50 KK connections to their equivalent uniplanar K connection.•We propose an objective criterion to identify the failure modes of KK connections.•An analytical expression to determine the KK resistance is proposed.
Data handling, reconstruction, and simulation for the KLOE experiment Ambrosino, F.; Antonelli, A.; Antonelli, M. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
12/2004, Volume:
534, Issue:
3
Journal Article
Peer reviewed
Open access
The broad physics program of the KLOE experiment is based on the high event rate at the Frascati φ
factory, and calls for an up-to-date system for data acquisition and processing. In this review of ...the KLOE offline environment, the architecture of the data-processing system and the programs developed for data reconstruction and Monte Carlo simulation are described, as well as the various procedures used for data handling and transfer between the different components of the system.
Fungus gardens of leaf-cutting ants harbor diverse alien fungi in addition to their fungal cultivar. Previous work suggested that alien microorganisms are likely derived from the substrata foraged by ...ant workers and incorporated into the fungus gardens. To test this hypothesis, we sampled 1014 garden fragments from 16 field colonies of Atta sexdens rubropilosa (a dicot-cutting ant) and Atta capiguara (a grass-cutting ant) in Brazil. From a total of 615 fungal isolates recovered, we observed similar diversity of fungi between colonies of both ant species. However, fungal communities differed in composition of taxa between ant colonies. Trichoderma spirale, Trichosporon chiarellii and Penicillium citrinum were prevalent accounting for 18.5%, 12.2% and 11.7% of the total isolates, respectively. As expected, fungal communities clustered in two major groups supporting the hypothesis that plant substratum has an impact on the composition of the alien fungi found in leaf-cutting ant gardens.
Forests represent an important role in the control of atmospheric emissions through carbon capture. However, in forest fires, the carbon stored during photosynthesis is released into the atmosphere. ...The carbon quantification, in forest burning, is important for the development of measures for its control. The aim of this study was to quantify CO2 and CO emissions of forest fires in Western Amazonia. In this paper, results are described of forest fire experiments conducted in Cruzeiro do Sul and Rio Branco, state of Acre, and Candeias do Jamari, state of Rondônia, Brazil. These cities are located in the Western portion of the Brazilian Amazon region. The biomass content per hectare, in the virgin forest, was measured by indirect methods using formulas with parameters of forest inventories in the central hectare of the test site. The combustion completeness was estimated by randomly selecting 10% of the total logs and twelve 2 × 2 m2 areas along three transects and examining their consumption rates by the fire. The logs were used to determine the combustion completeness of the larger materials (characteristic diameters larger than 10 cm) and the 2 × 2 m2 areas to determine the combustion completeness of small-size materials (those with characteristic diameters lower than 10 cm) and the. The overall biomass consumption by fire was estimated to be 40.0%, 41.2% and 26.2%, in Cruzeiro do Sul, Rio Branco and Candeias do Jamari, respectively. Considering that the combustion gases of carbon in open fires contain approximately 90.0% of CO2 and 10.0% of CO in volumetric basis, the average emission rates of these gases by the burning process, in the three sites, were estimated as 191 ± 46.7 t ha−1 and 13.5 ± 3.3 t ha−1, respectively.
Display omitted
•Carbon emission of a major Amazonian forest fire experiments.•Biomass consumption of different biomass size materials.•Biomass consumption as function of deforested area.
Queens of the leaf-cutting ant species Atta laevigata and Atta capiguara were collected soon after their mating flight and maintained in the laboratory until death. Ant corpses showing signs of ...contamination by insect pathogenic fungi were selected for fungal identification. Filamentous fungi such as Beauveria bassiana and Paecilomyces lilacinus actively sporulated in the ant's corpses. This is the first report of the latter fungus on reproductives of leaf-cutting ants. The fact that queens may acquire filamentous fungi including saprophytic and potential insect pathogens after their mating event is especially interesting regarding the impacts of such microbes on the establishment of a new nest.
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