805 research outputs found

    Especificidade do parasitóide Apanteles militaris (Hymenoptera: Braconidae) em relação ao hospedeiro Mythimna unipuncta (Lepidoptera: Noctuidae)

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    IV Encontro Nacional de Protecção Integrada, 3–4 Outubro, 1997, Angra do Heroísmo, Açores.Apanteles militaris (Walsh) é o mais importante parasitóide larvar de Mythimna unipuncta (Haworth) em todas as ilhas dos Açores. Pretendendo-se saber do modo de actuação deste parasitóide larvícola, procedeu-se ao estudo semanal da sua abundância e à do seu hospedeiro natural. Numa tentativa de compreender onde se encontra este parasitóide durante o Invermo, realizámos ensaios de parasitismo, em condições controladas, utilizando como hospedeiro larvas de Noctua pronuba L., Peridroma saucia (Hb), Xestia c-nigrum (L.), Spodoptera litoralis B., Agrotis ipsilon (Hüf.), Heliothis armigera (Hb.), Sesamia nonagrioides (Lef.), Autographa gamma (L.) e Pieris brassicae azorensis Rebel. Estes Lepidópteros foram seleccionados por existirem nos biótopos que são ocupados por M. unipuncta, apresentarem uma densidade importante nas condições ambientais dos Açores ou por serem hospedeiros de parasitóides pertencentes ao mesmo género. Para além de M. unipuncta, apenas S. nonagrioides e A. gamma apresentaram uma percentagem muito reduzida de larvas efectivamente parasitadas, 10 e 12,5%, respectivamente. Assim, a população açoreana de A. militaris apresenta uma grande especificidade em relação ao seu hospedeiro natural

    SplitBox: Toward Efficient Private Network Function Virtualization

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    This paper presents SplitBox, an efficient system for privacy-preserving processing of network functions that are outsourced as software processes to the cloud. Specifically, cloud providers processing the network functions do not learn the network policies instructing how the functions are to be processed. First, we propose an abstract model of a generic network function based on match-action pairs. We assume that this function is processed in a distributed manner by multiple honest-but-curious cloud service providers. Then, we introduce our SplitBox system for private network function virtualization and present a proof-of-concept implementation on FastClick, an extension of the Click modular router, using a firewall as a use case. Our experimental results achieve a throughput of over 2 Gbps with 1 kB-sized packets on average, traversing up to 60 firewall rules

    Fast privacy-preserving network function outsourcing

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    In this paper, we present the design and implementation of SplitBox, a system for privacy-preserving processing of network functions outsourced to cloud middleboxes—i.e., without revealing the policies governing these functions. SplitBox is built to provide privacy for a generic network function that abstracts the functionality of a variety of network functions and associated policies, including firewalls, virtual LANs, network address translators (NATs), deep packet inspection, and load balancers. We present a scalable design aiming to provide high throughput and low latency, by distributing functionalities to a few virtual machines (VMs), while providing provably secure guarantees. We implement SplitBox inside FastClick, an extension of the Click modular router, using Intel's DPDK to handle packet I/O. We evaluate our prototype experimentally to find its bottlenecks and stress-test its different components, vis-à-vis two widely used network functions, i.e., firewall and VLAN tagging. Our evaluation shows that, on commodity hardware, SplitBox can process packets close to line rate (i.e., 8.9Gbps) with up to 50 traversed policies

    Essential role of CFTR in PKA-dependent phosphorylation, alkalinization, and hyperpolarization during human dperm capacitation

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    Mammalian sperm require to spend a limited period of time in the female reproductive tract to become competent to fertilize in a process called capacitation. It is well established that HCO3 − is essential for capacitation because it activates the atypical soluble adenylate cyclase ADCY10 leading to cAMP production, and promotes alkalinization of cytoplasm, and membrane hyperpolarization. However, how HCO3 − is transported into the sperm is not well understood. There is evidence that CFTR activity is involved in the human sperm capacitation but how this channel is integrated in the complex signaling cascades associated with this process remains largely unknown. In the present work, we have analyzed the extent to which CFTR regulates different events in human sperm capacitation. We observed that inhibition of CFTR affects HCO3 −-entrance dependent events resulting in lower PKA activity. CFTR inhibition also affected cAMP/PKA-downstream events such as the increase in tyrosine phosphorylation, hyperactivated motility, and acrosome reaction. In addition, we demonstrated for the first time, that CFTR and PKA activity are essential for the regulation of intracellular pH, and membrane potential in human sperm. Addition of permeable cAMP partially recovered all the PKA-dependent events altered in the presence of inh-172 which is consistent with a role of CFTR upstream of PKA activation.Fil: Puga Molina, Lis del Carmen. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; ArgentinaFil: Pinto, Nicolás Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; ArgentinaFil: Torres Rodríguez, Paulina. Universidad Nacional Autónoma de México; MéxicoFil: Romarowski, Ana. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; ArgentinaFil: Vicens Sanchez, Alberto. Universidad Nacional Autónoma de México; MéxicoFil: Visconti, Pablo E.. University of Massachussets; Estados UnidosFil: Darszon, Alberto. Universidad Nacional Autónoma de México; MéxicoFil: Treviño, Claudia L.. Universidad Nacional Autónoma de México; MéxicoFil: Buffone, Mariano Gabriel. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; Argentin

    Transition from reciprocal cooperation to persistent behaviour in social dilemmas at the end of adolescence.

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    While human societies are extraordinarily cooperative in comparison with other social species, the question of why we cooperate with unrelated individuals remains open. Here we report results of a lab-in-the-field experiment with people of different ages in a social dilemma. We find that the average amount of cooperativeness is independent of age except for the elderly, who cooperate more, and a behavioural transition from reciprocal, but more volatile behaviour to more persistent actions towards the end of adolescence. Although all ages react to the cooperation received in the previous round, young teenagers mostly respond to what they see in their neighbourhood regardless of their previous actions. Decisions then become more predictable through midlife, when the act of cooperating or not is more likely to be repeated. Our results show that mechanisms such as reciprocity, which is based on reacting to previous actions, may promote cooperation in general, but its influence can be hindered by the fluctuating behaviour in the case of children
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