The moment-to-moment tasks performed by an individual can change in response to a shift of internal, e.g. body size or age, and external conditions, e.g. the number of workers currently engaged in ...another task. For this reason, the term “task allocation” is replacing the earlier concept of “division of labor” for describing an invariable association between worker body size and task. In the present study we hypothesized that, in the absence of changing conditions, different sized workers tend to perform different tasks. We also evaluated, using baits, the ability of colonies to regulate foraging activity through interactions between outgoing and returning foragers and the effect of ground temperature on the relative participation of different-sized workers to the foraging activity. Results suggest the existence in large and well-established colonies inhabiting a typical Mediterranean grassland area, of different-sized workers performing different tasks outside the nests. Moreover, we noticed the ability of colonies to adjust the relative participation of different sized foragers when provided with different-sized resources (baits). Finally, we recorded an effect of temperature on the average size of foragers, although no effect on size distribution was found.
Tapinoma
species, and more general dolichoderine ants, are able to produce a variety of volatile compounds they use as chemical defense, alarm, and communication pheromones. Among these, iridoids and ...volatile ketones are the predominant molecule classes produced by the anal glands of these ants. A recent taxonomic revision of the genus
Tapinoma
in Europe revealed that the supercolonial species
Tapinoma nigerrimum
consists of a complex of four cryptic species. Two of them,
Tapinoma magnum
and the newly described
Tapinoma darioi
, are closely related species that evolutionary diverged recently. In this work, we determine and characterize the chemical profile of pheromones and volatile compounds of two
Tapinoma
species. From a chemical point of view,
T. darioi
and
T. magnum
show both qualitative and quantitative differences in the pheromones produced, supporting the taxonomic revision of the
T. nigerrimum
complex. Our data confirm
T. darioi
and
T. magnum
as separate species also from a biochemical point of view demonstrating the value of chemotaxonomy as a suitable tool for integrative studies of species differentiation even for closely related taxa.
Selective seed consumption by harvester ants may be affected by several seed attributes, amongst which seed size and environmental availability play a prominent role. In the present study, we ...considered the effects of seed size and seed availability on the coexistence and diet preference of two Messor species (Messor wasmanni and Messor minor). M. wasmanni colonies collected the most abundant resource in the environment, grass seeds (Poaceae), according to their availability whilst M. minor showed a nonselective process. In addition, the two ant species showed a different seed size preference, with M. wasmanni adopting a selective strategy and M. minor a generalist strategy. However, competition for foraging resources between the two ant species (assessed by null model algorithms) seems not to affect their foraging behaviour. The lack of a competitive structure within the ant assemblage suggests, in fact, that resources are not a limiting factor for species coexistence.
Beginning in 2009, the CMS experiment will produce several petabytes of data each year which will be distributed over many computing centres geographically distributed in different countries. The CMS ...computing model defines how the data is to be distributed and accessed to enable physicists to efficiently run their analyses over the data. The analysis will be performed in a distributed way using Grid infrastructure. CRAB (CMS remote analysis builder) is a specific tool, designed and developed by the CMS collaboration, that allows the end user to transparently access distributed data. CRAB interacts with the local user environment, the CMS data management services and with the Grid middleware; it takes care of the data and resource discovery; it splits the user's task into several processes (jobs) and distributes and parallelizes them over different Grid environments; it performs process tracking and output handling. Very limited knowledge of the underlying technical details is required of the end user. The tool can be used as a direct interface to the computing system or can delegate the task to a server, which takes care of the job handling, providing services such as automatic resubmission in case of failures and notification to the user of the task status. Its current implementation is able to interact with gLite and OSG Grid middlewares. Furthermore, with the same interface, it enables access to local data and batch systems such as load sharing facility (LSF). CRAB has been in production and in routine use by end users since Spring 2004. It has been extensively used in studies to prepare the Physics Technical Design Report, in the analysis of reconstructed event samples generated during the Computing Software and Analysis Challenges and in the preliminary cosmic ray data taking. The CRAB architecture and the usage inside the CMS community will be described in detail, as well as the current status and future development.
Physiological tolerance of species to temperature, moisture or chemical-physical properties of the soil could be important in determining the distribution and abundance of ant nests. In the present ...study we investigated the possible differences in the nesting site microhabitat characteristics of two syntopic species of harvester ants of the genus Messor living in a Mediterranean homogeneous grassland area belonging to a single phytosociological association known as “Vulpio ligusticae-Dasypyretum villosi”. We tested to see whether the activity of the colonies of the two species directly altered the microhabitat characteristics of the nesting sites. Microhabitat characteristics were assessed quantifying several abiotic factors (light, temperature, soil moisture, soil pH, nitrogen) by means of the Ellenberg Bioindication Model. The model represents a simple way of interpreting the vegetation pattern in terms of ecological factors from the perspective of the plants and can be considered an effective and promising approach to link animal and plant ecology. Our data showed significant differences in the nesting site microhabitat characteristics partially due to a different capacity of the two species to alter nesting site proprieties. Possible differences in the physiological tolerance of these species to moisture gradients could be crucial in determining the distribution and abundance of their nests.
Automation of user analysis workflow in CMS Spiga, D; Cinquilli, M; Codispoti, G ...
Journal of physics. Conference series,
04/2010, Letnik:
219, Številka:
7
Journal Article
Recenzirano
Odprti dostop
CMS has a distributed computing model, based on a hierarchy of tiered regional computing centres. However, the end physicist is not interested in the details of the computing model nor the complexity ...of the underlying infrastructure, but only to access and use efficiently and easily the remote services. The CMS Remote Analysis Builder (CRAB) is the official CMS tool that allows the access to the distributed data in a transparent way. We present the current development direction, which is focused on improving the interface presented to the user and adding intelligence to CRAB such that it can be used to automate more and more the work done on behalf of user. We also present the status of deployment of the CRAB system and the lessons learnt in deploying this tool to the CMS collaboration.
Establishing efficient and scalable operations of the CMS distributed computing system critically relies on the proper integration, commissioning and scale testing of the data and workload management ...tools, the various computing workflows and the underlying computing infrastructure, located at more than 50 computing centres worldwide and interconnected by the Worldwide LHC Computing Grid. Computing challenges periodically undertaken by CMS in the past years with increasing scale and complexity have revealed the need for a sustained effort on computing integration and commissioning activities. The Processing and Data Access (PADA) Task Force was established at the beginning of 2008 within the CMS Computing Program with the mandate of validating the infrastructure for organized processing and user analysis including the sites and the workload and data management tools, validating the distributed production system by performing functionality, reliability and scale tests, helping sites to commission, configure and optimize the networking and storage through scale testing data transfers and data processing, and improving the efficiency of accessing data across the CMS computing system from global transfers to local access. This contribution reports on the tools and procedures developed by CMS for computing commissioning and scale testing as well as the improvements accomplished towards efficient, reliable and scalable computing operations. The activities include the development and operation of load generators for job submission and data transfers with the aim of stressing the experiment and Grid data management and workload management systems, site commissioning procedures and tools to monitor and improve site availability and reliability, as well as activities targeted to the commissioning of the distributed production, user analysis and monitoring systems.
The CMS experiment at LHC started using the Resource Broker (by the EDG and LCG projects) to submit Monte Carlo production and analysis jobs to distributed computing resources of the WLCG ...infrastructure over 6 years ago. Since 2006 the gLite Workload Management System (WMS) and Logging & Bookkeeping (LB) are used. The interaction with the gLite-WMS/LB happens through the CMS production and analysis frameworks, respectively ProdAgent and CRAB, through a common component, BOSSLite. The important improvements recently made in the gLite-WMS/LB as well as in the CMS tools and the intrinsic independence of different WMS/LB instances allow CMS to reach the stability and scalability needed for LHC operations. In particular the use of a multi-threaded approach in BOSSLite allowed to increase the scalability of the systems significantly. In this work we present the operational set up of CMS production and analysis based on the gLite-WMS and the performances obtained in the past data challenges and in the daily Monte Carlo productions and user analysis usage in the experiment.
CMS offline web tools Metson, S; Belforte, S; Bockelman, B ...
Journal of physics. Conference series,
07/2008, Letnik:
119, Številka:
8
Journal Article
Recenzirano
Odprti dostop
We describe a relatively new effort within CMS to converge on a set of web based tools, using state of the art industry techniques, to engage with the CMS offline computing system. CMS collaborators ...require tools to monitor various components of the computing system and interact with the system itself. The current state of the various CMS web tools is described along side current planned developments. The CMS collaboration comprises of nearly 3000 people from all over the world. As well as its collaborators, its computing resources are spread all over globe and are accessed via the LHC grid to run analysis, large scale production and data transfer tasks. Due to the distributed nature of collaborators effective provision of collaborative tools is essential to maximise physics exploitation of the CMS experiment, especially when the size of the CMS data set is considered. CMS has chosen to provide such tools over the world wide web as a top level service, enabling all members of the collaboration to interact with the various offline computing components. Traditionally web interfaces have been added in HEP experiments as an afterthought. In the CMS offline we have decided to put web interfaces, and the development of a common CMS web framework, on an equal footing with the rest of the offline development. Tools exist within CMS to transfer and catalogue data (PhEDEx and DBS/DLS), run Monte Carlo production (ProdAgent) and submit analysis (CRAB). Effective human interfaces to these systems are required for users with different agendas and practical knowledge of the systems to effectively use the CMS computing system. The CMS web tools project aims to provide a consistent interface to all these tools.
The fitness of an organism can be affected by conditions experienced during early development. In light of the impact that oxidative stress can have on the health and ageing of a bird species, this ...study evaluated factors accounting for the variation in oxidative stress levels in nestlings of the Eurasian kestrel (Falco tinnunculus) by measuring the serum concentration of reactive oxygen metabolites and the serum antioxidant barrier against hypochlorite-induced oxidation. The ratio between these two variables was considered as an index of oxidative stress, with higher values meaning higher oxidative damage. Six-chick broods showed the highest level of oxidative stress, while no effect of sex was found. Age showed an inverse relationship with the oxidants and the levels of oxidative stress, with younger birds having higher levels. Hatching date, body condition, body mass and carotenoid concentration did not show any relationship with oxidants, antioxidants or degree of oxidative stress. These findings suggest that intrabrood sibling competition could play a role in determining oxidative stress, and that in carnivorous birds other antioxidant molecules could be more important than carotenoids to reduce oxidative stress.
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