391 research outputs found
The Relativistic Hopfield network: rigorous results
The relativistic Hopfield model constitutes a generalization of the standard
Hopfield model that is derived by the formal analogy between the
statistical-mechanic framework embedding neural networks and the Lagrangian
mechanics describing a fictitious single-particle motion in the space of the
tuneable parameters of the network itself. In this analogy the cost-function of
the Hopfield model plays as the standard kinetic-energy term and its related
Mattis overlap (naturally bounded by one) plays as the velocity. The
Hamiltonian of the relativisitc model, once Taylor-expanded, results in a
P-spin series with alternate signs: the attractive contributions enhance the
information-storage capabilities of the network, while the repulsive
contributions allow for an easier unlearning of spurious states, conferring
overall more robustness to the system as a whole. Here we do not deepen the
information processing skills of this generalized Hopfield network, rather we
focus on its statistical mechanical foundation. In particular, relying on
Guerra's interpolation techniques, we prove the existence of the infinite
volume limit for the model free-energy and we give its explicit expression in
terms of the Mattis overlaps. By extremizing the free energy over the latter we
get the generalized self-consistent equations for these overlaps, as well as a
picture of criticality that is further corroborated by a fluctuation analysis.
These findings are in full agreement with the available previous results.Comment: 11 pages, 1 figur
The Earthlike Shoreline Morphology of Titan's Ontario Lacus
Ontario Lacus' shoreline features include Earth-like rivers, deltas and flooded topography. Ontario is a dynamic lake, similar in many ways to terrestrial lakes, with active shoreline processes
El roedor silvestre Akodon azarae (Cricetidae: Sigmodontinae) como hospedador intermediario de Taenia taeniaeformis (Cestoda: Cyclophyllidea) en granjas avícolas del centro de Argentina
This work reports strobilocerci of Taenia taeniaeformis in the rodent Akodon azarae. A total of 289 rodents were captured on poultry farms in Central Argentina, belonging to the following species: A. azarae, Calomys laucha, C. musculinus, Oligoryzomys flavescens, and Mus musculus. All rodents were examined for parasites. Only A. azarae was parasitized with strobilocerci larvae. Prevalence, mean intensity, and mean abundance of the infection in the liver were 8.33%, 2.09 and 0.17, respectively. No differences were observed between the sexes of the infected rodents. Since in natural environments no cysts were reported, A. azarae is susceptible to get infected with T. taeniaeformis when frequents domestic and peridomestic habitats. Taenia taeniaeformis may have three different life cycles in the studied area: 1) one domestic cycle between Rattus norvegicus and pets in the surrounding of the farms, since R. norvegicus was observed to be parasitized; 2) another domestic cycle between A. azarae and the pets when such pets come to the farm fences; and 3) a wild cycle between A. azarae and Leopardus geoffroyi (Carnivora: Felidae), since it was observed that A. azarae is preyed by this felid and their feces were found parasitized with eggs of Taenia sp. in the study area.Este trabajo informa la presencia de estrobilocercos de Taenia taeniaeformis en el roedor Akodon azarae. Un total de 289 roedores pertenecientes a las especies A. azarae, Calomys laucha, C. musculinus, Oligoryzomys flavescens y Mus musculus fueron capturados en granjas avícolas del centro de Argentina. Todos los roedores fueron examinados en busca de parásitos. Sólo A. azarae presentó quistes de cestodes en el hígado. Los valores de prevalencia, intensidad media y abundancia media de la infestación fueron 8.33%, 2.09 y 0.17, respectivamente, y no se observó ninguna diferencia entre los sexos de los roedores infectados. Se concluye que A. azarae es susceptible de infectarse con T. taeniaeformis cuando frecuenta hábitats domésticos y peridomésticos, ya que en ambientes naturales nunca fue registrada su presencia en estos roedores. Los resultados de este estudio sugieren que T. taeniaeformis mantiene tres tipos diferentes de ciclos de vida en el área estudiada: 1) un ciclo doméstico entre Rattus norvegicus y mascotas (perros y gatos), ya que R. norvegicus ha sido encontrada parasitada en las granjas; 2) otro ciclo doméstico entre A. azarae y mascotas cuando estas últimas se acercan a los alambrados de las granjas; y 3) un ciclo silvestre entre A. azarae y Leopardus geoffroyi (Carnivora: Felidae), ya que se ha observado en el área de estudio que A. azarae es predado por este felino en cuyas heces se han encontrado huevos de Taenia sp.Facultad de Ciencias Naturales y Muse
El roedor silvestre Akodon azarae (Cricetidae: Sigmodontinae) como hospedador intermediario de Taenia taeniaeformis (Cestoda: Cyclophyllidea) en granjas avícolas del centro de Argentina
This work reports strobilocerci of Taenia taeniaeformis in the rodent Akodon azarae. A total of 289 rodents were captured on poultry farms in Central Argentina, belonging to the following species: A. azarae, Calomys laucha, C. musculinus, Oligoryzomys flavescens, and Mus musculus. All rodents were examined for parasites. Only A. azarae was parasitized with strobilocerci larvae. Prevalence, mean intensity, and mean abundance of the infection in the liver were 8.33%, 2.09 and 0.17, respectively. No differences were observed between the sexes of the infected rodents. Since in natural environments no cysts were reported, A. azarae is susceptible to get infected with T. taeniaeformis when frequents domestic and peridomestic habitats. Taenia taeniaeformis may have three different life cycles in the studied area: 1) one domestic cycle between Rattus norvegicus and pets in the surrounding of the farms, since R. norvegicus was observed to be parasitized; 2) another domestic cycle between A. azarae and the pets when such pets come to the farm fences; and 3) a wild cycle between A. azarae and Leopardus geoffroyi (Carnivora: Felidae), since it was observed that A. azarae is preyed by this felid and their feces were found parasitized with eggs of Taenia sp. in the study area.Este trabajo informa la presencia de estrobilocercos de Taenia taeniaeformis en el roedor Akodon azarae. Un total de 289 roedores pertenecientes a las especies A. azarae, Calomys laucha, C. musculinus, Oligoryzomys flavescens y Mus musculus fueron capturados en granjas avícolas del centro de Argentina. Todos los roedores fueron examinados en busca de parásitos. Sólo A. azarae presentó quistes de cestodes en el hígado. Los valores de prevalencia, intensidad media y abundancia media de la infestación fueron 8.33%, 2.09 y 0.17, respectivamente, y no se observó ninguna diferencia entre los sexos de los roedores infectados. Se concluye que A. azarae es susceptible de infectarse con T. taeniaeformis cuando frecuenta hábitats domésticos y peridomésticos, ya que en ambientes naturales nunca fue registrada su presencia en estos roedores. Los resultados de este estudio sugieren que T. taeniaeformis mantiene tres tipos diferentes de ciclos de vida en el área estudiada: 1) un ciclo doméstico entre Rattus norvegicus y mascotas (perros y gatos), ya que R. norvegicus ha sido encontrada parasitada en las granjas; 2) otro ciclo doméstico entre A. azarae y mascotas cuando estas últimas se acercan a los alambrados de las granjas; y 3) un ciclo silvestre entre A. azarae y Leopardus geoffroyi (Carnivora: Felidae), ya que se ha observado en el área de estudio que A. azarae es predado por este felino en cuyas heces se han encontrado huevos de Taenia sp.Facultad de Ciencias Naturales y Muse
Dirofilariosis canina: microfilaremia en perros de la ribera del Río de la Plata, Argentina
La dirofilariosis es una enfermedad zoonótica causada por Dirofilaria immitis y transmitida por mosquitos. Este trabajo presenta un relevamiento de la microfilaremia en perros en la ribera del Río de la Plata utilizando la técnica de Knott modificada y estudia posibles especies de mosquitos como vectores. A través de consultorios veterinarios y centros de zoonosis de Villa Domínico, Quilmes Este, La Plata y Berisso (Buenos Aires) se obtuvieron 265 muestras de sangre de perros y se completó una encuesta (sexo, edad, pedigree, talla, largo del pelo, manejo de las mascotas y tratamiento con ivermectina). Se capturaron y disecaron 412 mosquitos con aspirador manual sobre cebo humano en la ribera del Río de la Plata para observar formas filariformes. El 78,8% de las muestras de sangre correspondieron a hembras, el 76,2% de los perros fueron mestizos, las tallas chicas a medianas (30,1% y 41,1% respectivamente) y el 38,2% de las mascotas permanecía las 24 horas fuera de la vivienda. El 73% de las muestras correspondieron a perros menores de 6 años. Se detectaron 6 casos Knott positivos (prevalencia 2,26%). El 50% de los casos positivos eran asintomáticos. Si bien los machos estuvieron más parasitados que las hembras (diferencias significativas), se estima que ello está asociado a un manejo especial de las mascotas hembras por parte de los dueños. Éstas suelen permanecer mayor tiempo en el interior de la vivienda y así tendrían menor probabilidad de contacto con mosquitos. Se observaron diferencias significativas entre edades. Los adultos estuvieron más parasitados que los jóvenes. No se hallaron formas filariformes en los mosquitos disecados. Se recomienda el test de Knott modificado como técnica rápida, económica y efectiva para el diagnóstico de dirofilariosis, siempre que el canino no haya sido tratado con ivermectin
The TOTEM Experiment at the CERN Large Hadron Collider
The TOTEM Experiment will measure the total pp cross-section with the luminosity independent method and study elastic and diffractive scattering at the LHC. To achieve optimum forward coverage for charged particles emitted by the pp collisions in the interaction point IP5, two tracking telescopes, T1 and T2, will be installed on each side in the pseudorapidity region 3,1 <h< 6,5, and Roman Pot stations will be placed at distances of 147m and 220m from IP5. Being an independent experiment but technically integrated into CMS, TOTEM will first operate in standalone mode to pursue its own physics programme and at a later stage together with CMS for a common physics programme. This article gives a description of the TOTEM apparatus and its performance
Diversity, host specialization, and geographic structure of filarial nematodes infecting Malagasy bats
We investigated filarial infection in Malagasy bats to gain insights into the diversity of these parasites and explore the factors shaping their distribution. Samples were obtained from 947 individual bats collected from 52 sites on Madagascar and representing 31 of the 44 species currently recognized on the island. Samples were screened for the presence of micro-and macro-parasites through both molecular and morphological approaches. Phylogenetic analyses showed that filarial diversity in Malagasy bats formed three main groups, the most common represented by Litomosa spp. infecting Miniopterus spp. (Miniopteridae); a second group infecting Pipistrellus cf. hesperidus (Vespertilionidae) embedded within the Litomosoides cluster, which is recognized herein for the first time from Madagascar; and a third group composed of lineages with no clear genetic relationship to both previously described filarial nematodes and found in M. griveaudi, Myotis goudoti, Neoromicia matroka (Vespertilionidae), Otomops madagascariensis (Molossidae), and Paratriaenops furculus (Hipposideridae). We further analyzed the infection rates and distribution pattern of Litomosa spp., which was the most diverse and prevalent filarial taxon in our sample. Filarial infection was disproportionally more common in males than females in Miniopterus spp., which might be explained by some aspect of roosting behavior of these cave-dwelling bats. We also found marked geographic structure in the three Litomosa clades, mainly linked to bioclimatic conditions rather than host-parasite associations. While this study demonstrates distinct patterns of filarial nematode infection in Malagasy bats and highlights potential drivers of associated geographic distributions, future work should focus on their alpha taxonomy and characterize arthropod vectors
The role of life cycle assessment in supporting sustainable agri-food systems: A review of the challenges
Life cycle thinking is increasingly seen as a key concept for ensuring a transition towards more sustainable production and consumption patterns. As food production systems and consumption patterns
are among the leading drivers of impacts on the environment, it is important to assess and improve foodrelated supply chains as much as possible. Over the years, life cycle assessment has been used extensively to assess agricultural systems and food processing and manufacturing activities, and compare alternatives “from field to fork” and through to food waste management. Notwithstanding the efforts, several methodological aspects of life cycle assessment still need further improvement in order to ensure adequate and robust support for decision making in both business and policy development contexts. This paper discusses the challenges for life cycle assessment arising from the complexity of food systems, and recommends research priorities for both scientific development and improvements in practical implementation. In summary, the intrinsic variability of food production systems requires dedicated modelling approaches, including addressing issues related to: the distinction between technosphere and ecosphere; the most appropriate functional unit; the multi-functionality of biological systems; and the modelling of the emissions and how this links with life cycle impact assessment. Also, data availability and interpretation of the results are two issues requiring further attention, including how to account for consumer behaviour.info:eu-repo/semantics/publishedVersio
In quest of reducing the environmental impacts of food production and consumption
Food supply chains are increasingly associated with environmental and socio-economic impacts. An
increasing global population, an evolution in consumers' needs, and changes in consumption models
pose serious challenges to the overall sustainability of food production and consumption. Life cycle
thinking (LCT) and assessment (LCA) are key elements in identifying more sustainable solutions for
global food challenges. In defining solutions to major global challenges, it is fundamentally important to
avoid burden shifting amongst supply chain stages and amongst typologies of impacts, and LCA should,
therefore, be regarded as a reference method for the assessment of agri-food supply chains. Hence, this
special volume has been prepared to present the role of life cycle thinking and life cycle assessment in: i)
the identification of hotspots of impacts along food supply chains with a focus on major global challenges; ii) food supply chain optimisation (e.g. productivity increase, food loss reduction, etc.) that delivers sustainable solutions; and iii) assessment of future scenarios arising from both technological improvements and behavioural changes, and under different environmental conditions (e.g. climate
change). This special volume consists of a collection of papers from a conference organized within the
last Universal Exposition (EXPO2015) “LCA for Feeding the planet and energy for life” in Milan (Italy) in
2015 as well as other contributions that were submitted in the year after the conference that addressed
the same key challenges presented at the conference. The papers in the special volume address some of
the key challenges for optimizing food-related supply chains by using LCA as a reference method for
environmental impact assessment. Beyond specific methodological improvements to better tailor LCA
studies to food systems, there is a clear need for the LCA community to “think outside the box”, exploring
complementarity with other methods and domains. The concepts and the case studies presented in this
special volume demonstrate how cross-fertilization among difference science domains (such as envi-
ronmental, technological, social and economic ones) may be key elements of a sustainable “today and
tomorrow” for feeding the planet.info:eu-repo/semantics/publishedVersio
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