4,561 research outputs found

    X.509 certificate error testing

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    X.509 Certificates are used by a wide range of technologies to verify identities, while the SSL protocol is used to provide a secure encrypted tunnel through which data can be sent over a public network. Combined both of these technologies provides the basis of the public key infrastructure (PKI). While the concept of PKI is a good idea, the different implementation of the technologies in different operating system and clients often lead to weaknesses. This paper proposes a methodology to automate the testing of SSL clients by generating both bogus and malformed certificates in order to evaluate the client’s response and identify potential threats to network infrastructures

    Direct Detection of Leptophilic Dark Matter in a Model with Radiative Neutrino Masses

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    We consider an electro-weak scale model for Dark Matter (DM) and radiative neutrino mass generation. Despite the leptophilic nature of DM with no direct couplings to quarks and gluons, scattering with nuclei is induced at the 1-loop level through photon exchange. Effectively, there are charge-charge, dipole-charge and dipole-dipole interactions. We investigate the parameter space consistent with constraints from neutrino masses and mixing, charged lepton-flavour violation, perturbativity, and the thermal production of the correct DM abundance, and calculate the expected event rate in DM direct detection experiments. We show that current data from XENON100 start to constrain certain regions of the allowed parameter space, whereas future data from XENON1T has the potential to significantly probe the model.Comment: 24 pages, 8 figures, 2 tables, discussion of large theta13 added, version to appear in PR

    The Semantics and Pragmatics of Right Dislocation: Odd thing, that.

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    The sentence "She's a smart one, that Diana" is a so-called right dislocation construction: the noun phrase "that Diana" occurs at the right edge of the sentence and the sentence itself only realizes a pronoun ("she") to refer to Diana. This construction is particularly common among British English speakers. Whereas prior research has focused on the structure and interpretation of the construction, my research explores the hypothesis that speakers use the construction when they expect their interlocutors to agree with them about the propositional content of the utterance (e.g., that Diana is a smart person, in the aforementioned example). In summer 2017 I ran an experiment with 38 native British English speakers, administering a survey in which each participant rated the acceptability of a target sentence in context on a 6-point Likert scale. Target sentences varied minimally between right dislocated and non-dislocated variants, and contexts were either such that the speaker would expect the listener to agree with the propositional content of the utterance, or such that the speaker would expect the listener to disagree. Each target sentence was judged within both contexts. While no significant difference was found between the agree and disagree contexts among the right dislocated target sentences as a whole, the variation in response patterns both between participants and between items reveal potential routes for further exploration of right dislocation constructions' social meaning in the future.Arts & Sciences Undergraduate Research ScholarshipArts & Sciences International Research GrantNo embargoAcademic Major: ChineseAcademic Major: Linguistic

    Economic and environmental analysis of the introduction of legumes in livestock farming systems

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    Legumes in low input systems are becoming increasingly important. The socioeconomic implication of the adoption of novel legumes species has been assessed in sheep and dairy cattle grazing systems in Europe using a biological model which has been linked to linear programming models. In the economic sub-model, the mathematical programming models produce an economic evaluation of the legumes in a farming system context, emphasising the land allocation and the availability of nutrients during the different seasons of the production cycle. Then the paper evaluates the impact of adopting the legumes on the regional income and production. In the UK and Germany, the introduction of legumes results in sizeable gains for the farmers whereas in Italy and France the gains are smaller

    Neutrino masses and μ\mu terms in a supersymmetric extra U(1) model

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    We propose a supersymmetric extra U(1) model, which can generate small neutrino masses and necessary μ\mu terms, simultaneously. Fields including quarks and leptons are embedded in three 27{\bf 27}s of E6E_6 in a different way among generations. The model has an extra U(1) gauge symmetry at TeV regions, which has discriminating features from other models studied previously. Since a neutrino mass matrix induced in the model has a constrained texture with limited parameters, it can give a prediction. If we impose neutrino oscillation data to fix those parameters, a value of sinθ13\sin\theta_{13} can be determined. We also discuss several phenomenological features which are discriminated from the ones of the MSSM.Comment: 27 pages, 2 figures, final version for publicatio

    Magnetic nulls and super-radial expansion in the solar corona

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    Magnetic fields in the sun's outer atmosphere -- the corona -- control both solar-wind acceleration and the dynamics of solar eruptions. We present the first clear observational evidence of coronal magnetic nulls in off-limb linearly polarized observations of pseudostreamers, taken by the Coronal Multichannel Polarimeter (CoMP) telescope. These nulls represent regions where magnetic reconnection is likely to act as a catalyst for solar activity. CoMP linear-polarization observations also provide an independent, coronal proxy for magnetic expansion into the solar wind, a quantity often used to parameterize and predict the solar wind speed at Earth. We introduce a new method for explicitly calculating expansion factors from CoMP coronal linear-polarization observations, which does not require photospheric extrapolations. We conclude that linearly-polarized light is a powerful new diagnostic of critical coronal magnetic topologies and the expanding magnetic flux tubes that channel the solar wind

    A novel metric for coronal MHD models

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    [1] In the interest of quantitatively assessing the capabilities of coronal MHD models, we have developed a metric that compares the structures of the white light corona observed with SOHO LASCO C2 to model predictions. The MAS model is compared to C2 observations from two Carrington rotations during solar cycle 23, CR1913 and CR1984, which were near the minimum and maximum of solar activity, respectively, for three radial heights, 2.5 R⊙, 3.0 R⊙, and 4.5 R⊙. In addition to simulated polarization brightness images, we create a synthetic image based on the field topology along the line of sight in the model. This open-closed brightness is also compared to LASCO C2 after renormalization. In general, the model\u27s magnetic structure is a closer match to observed coronal structures than the model\u27s density structure. This is expected from the simplified energy equations used in current global corona MHD models

    Open and / or laparoscopic surgical treatment of liver hydatic cysts

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    Hydatid disease is a severe parasitic disease with a widely ranging distribution. In the human being the liver is the most frequent organ affected. 1 The treatment should be individualized to the morphology, size, number and location of the cysts, that is why a variety of surgical operations have been advocated from complete resection like total pericystectomy or partial hepatectomy to laparoscopy to a minimally invasive procedures like percutaneous aspiration of cysts to conservative drug therapy. 3-4 This study compares laparoscopic versus open management of the hydatid cyst of liver the surgical approach to liver echinococcosis is still a controversial issue and shows our results of surgical treatment of liver hydatid cysts during a 3-years period

    Molecular and behavioral mechanisms mediating paclitaxel-induced changes in affect-like behavior in mice

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    The antineoplastic paclitaxel is associated with negative affective outcomes, such as depression, anxiety, and decreased quality of life during treatment and convalescence. With the Baby Boomer population approaching peak cancer age, it is dire that the mechanisms behind paclitaxel-induced changes in mood are uncovered. Cancer-free male and female C57BL/6J mice were treated with one set of four injections of vehicle or paclitaxel (32mg/kg cumulative), or two sets of four injections of vehicle or paclitaxel (64mg/kg cumulative), and periodically assessed for depression-like behaviors. Paclitaxel caused significant, time-dependent deficits in sucrose preference and operant responding for palatable food. Because there is growing evidence to support the role of kappa opioid receptors (KORs) in stress-mediated depression and reward dysfunction, we investigated KOR signaling as a putative mechanism of paclitaxel-induced depression-like behaviors. The selective KOR antagonist norbinaltorphimine (norBNI) reversed paclitaxel-induced attenuation of sucrose preference. At the molecular level, paclitaxel time-dependently induced an increase in the expression of Prodynorphin mRNA, the precursor for endogenous KOR agonists, in the nucleus accumbens (NAc). Using the [35S]GTPγS assay, we discovered that a history of paclitaxel time-dependently attenuated activation of dopamine D2 receptors (D2R) and KORs in the NAc but not caudate putamen. These data suggest that paclitaxel-induced changes in affect-like behavior may be due to time- and region-dependent dysregulation of KOR and D2R signaling. These observations help to establish the roles of KOR and D2R systems in paclitaxel-induced disruption of behavioral reward, thus revealing potential neurochemical targets for therapeutic intervention in cancer survivors with treatment-resistant depression.https://scholarscompass.vcu.edu/gradposters/1038/thumbnail.jp
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