7,222 research outputs found
Increasing Performances of TCP Data Transfers Through Multiple Parallel Connections
Although Transmission Control Protocol (TCP) is a widely deployed and successful protocol, it shows some limitations in present-day environments. In particular, it is unable to exploit multiple (physical or logical) paths between two hosts. This paper presents PATTHEL, a session-layer solution designed for parallelizing stream data transfers. Parallelization is achieved by striping the data flow among multiple TCP channels. This solution does not require invasive changes to the networking stack and can be implemented entirely in user space. Moreover, it is flexible enough to suit several scenarios - e.g. it can be used to split a data transfer among multiple relays within a peer-to-peer overlay networ
Potato R1 resistance gene confers resistance against Phytophthora infestans in transgenic tomato plants
Tomato is challenged by several pathogens which cause loss of production. One such pathogen is the oomycete Phytophthora infestans which is able to attack all the aerial parts of the plant. Although a wide range of resistance sources are available, genetic control of this disease is not yet successful. Pyramiding R-genes through genetic transformation could be a straightforward way to produce tomato and potato lines carrying durable resistance to P. infestans. In this work the R1 potato gene was transferred into tomato lines. The tomato transgenic lines were analyzed by using q-RT-PCR and progeny segregation to determine the gene copy number. To test the hypothesis that R1 represents a specifically regulated R-gene, transgenic tomato plants were inoculated with P. infestans isolate 88133 and IPO. All the plants containing the R1 gene were resistant to the late blight isolate IPO-0 and susceptible to isolate 88133. These results provide evidence for specific activation of the R1 gene during pathogen challenge. Furthermore, evidence for enhancement of PR-1 gene expression during P. infestans resistance response was obtained
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Observer mediation as a function of serial or simultaneous exposure to a model\u27s behavior and intructions concerning the test of learning.
In past research concerning spontaneous motoric and symbolic mediation in observational learning (Berger, et al . , 1979), familiar observers who had symbolic codes for the model\u27s behavior benefited from the use of these codes; unfamiliar observers who had no available symbolic codes benefited from the use of motor mimicry. Familiar observers, however, still engaged in a considerable amount of mimicry. This study examined two hypotheses concerning why familiar subjects continued to mimic: that mimicry acts as a temporary coding device when observers do not have enough time to think of familiar symbolic codes for a model\u27s behavior and that observers increase their use of mimicry when they expect to have to perform the model\u27s behavior as a test of their learning. The results showed that there was no difference in mimicry between groups of observers who did have enough time to think of symbolic codes and those who did not. Observers who expected to have to perform the model\u27s behavior engaged in more mimicry than those who expected a recognition test. In addition, some observers reported engaging in unintentional mimicry. The results suggest that mimicry in past research may have occurred automatically and unintentionally or in preparation for a performance test
A model for Hopfions on the space-time S^3 x R
We construct static and time dependent exact soliton solutions for a theory
of scalar fields taking values on a wide class of two dimensional target
spaces, and defined on the four dimensional space-time S^3 x R. The
construction is based on an ansatz built out of special coordinates on S^3. The
requirement for finite energy introduces boundary conditions that determine an
infinite discrete spectrum of frequencies for the oscillating solutions. For
the case where the target space is the sphere S^2, we obtain static soliton
solutions with non-trivial Hopf topological charges. In addition, such hopfions
can oscillate in time, preserving their topological Hopf charge, with any of
the frequencies belonging to that infinite discrete spectrum.Comment: Enlarged version with the time-dependent solutions explicitly given.
One reference and two eps figures added. 14 pages, late
Like grandparents, like parents: Empirical evidence and psychoanalytic thinking on the transmission of parenting styles
The authors discuss the issue of intergenerational transmission of parenting from an empirical and psychoanalytic perspective. After presenting a framework to explain their conception of parenting, they describe intergenerational transmission of parenting as a key to interpreting and eventually changing parenting behaviors. Then they present (1) the empirical approach aimed at determining if there is actually a stability across generations that contributes to harsh parenting and eventually maltreatment and (2) the psyphoanalytic thinking that seeks to explain the continuity in terms of representations and clinical phenomena. The authors also discuss the relationship between the attachment and the caregiving systems and hypothesize a common base for the two systems in childhood experience. Finally, they propose the psychoanalytic perspective as a fruitful theoretical framework to integrate the evidence for the neurophysiological mediators and moderators of intergenerational transmission. Psychoanalytically informed research can provide clinically relevant insights and hypotheses to be tested
Analisi Morfometrica dei Cromosomi del Coniglio (Oryctolagus Cuniculus L.)
RIASSUNTOSono stati studiati i cromosomi di coniglio (Oryctolagus cuniculus L.).Il numero diploide dei cromosomi in cellule somatiche e risultato di 2 n= 44. L'analisi morfologica e metrica di essi ha permesso la distinzione in gruppi di cromosomi affini. Una tale classificazione si pensa possa essere utile in ricerche di cariologia comparata nell'ambito dei Leporidae
Events with Isolated Charged Leptons and Large Missing Transverse Momentum at HERA
Striking events with isolated charged leptons, large missing transverse
momentum and large transverse momentum of the hadronic final state were
observed at the electron proton collider HERA in a data sample corresponding to
a luminosity of about 130 pb-1. The H1 collaboration observed 11 events with
isolated electrons or muons and with transverse momentum above 25 GeV. Only
3.4+-0.6 events were expected from Standard Model (SM) processes. Six of these
events have a transverse momentum of greater than 40 GeV, while 1.3+-0.3 events
were expected. The ZEUS collaboration observed good agreement with the SM.
However, ZEUS found two events with a similar event topology, but tau leptons
instead of electrons or muons in the final state. Only 0.2+-0.05 events were
expected from SM processes. For various hypotheses the compatibility of the
experimental results was investigated with respect to the SM and with respect
to possible explanations beyond the SM. Prospects for the high-luminosity
HERA-II data taking period are given
Increasing Performances of TCP Data Transfers Through Multiple Parallel Connections
Although Transmission Control Protocol (TCP) is a widely deployed and successful protocol, it shows some limitations in present-day environments. In particular, it is unable to exploit multiple (physical or logical) paths between two hosts. This paper presents PATTHEL, a session-layer solution designed for parallelizing stream data transfers. Parallelization is achieved by striping the data flow among multiple TCP channels. This solution does not require invasive changes to the networking stack and can be implemented entirely in user space. Moreover, it is flexible enough to suit several scenarios - e.g. it can be used to split a data transfer among multiple relays within a peer-to-peer overlay network
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