68 research outputs found

    Separating Agent-Functioning and Inter-Agent Coordination by Activated Modules: The DECOMAS Architecture

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    The embedding of self-organizing inter-agent processes in distributed software applications enables the decentralized coordination system elements, solely based on concerted, localized interactions. The separation and encapsulation of the activities that are conceptually related to the coordination, is a crucial concern for systematic development practices in order to prepare the reuse and systematic integration of coordination processes in software systems. Here, we discuss a programming model that is based on the externalization of processes prescriptions and their embedding in Multi-Agent Systems (MAS). One fundamental design concern for a corresponding execution middleware is the minimal-invasive augmentation of the activities that affect coordination. This design challenge is approached by the activation of agent modules. Modules are converted to software elements that reason about and modify their host agent. We discuss and formalize this extension within the context of a generic coordination architecture and exemplify the proposed programming model with the decentralized management of (web) service infrastructures

    The Sloan Digital Sky Survey Quasar Catalog V. Seventh Data Release

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    We present the fifth edition of the Sloan Digital Sky Survey (SDSS) Quasar Catalog, which is based upon the SDSS Seventh Data Release. The catalog, which contains 105,783 spectroscopically confirmed quasars, represents the conclusion of the SDSS-I and SDSS-II quasar survey. The catalog consists of the SDSS objects that have luminosities larger than M_i = -22.0 (in a cosmology with H_0 = 70 km/s/Mpc Omega_M = 0.3, and Omega_Lambda = 0.7) have at least one emission line with FWHM larger than 1000 km/s or have interesting/complex absorption features, are fainter than i > 15.0 and have highly reliable redshifts. The catalog covers an area of 9380 deg^2. The quasar redshifts range from 0.065 to 5.46, with a median value of 1.49; the catalog includes 1248 quasars at redshifts greater than four, of which 56 are at redshifts greater than five. The catalog contains 9210 quasars with i < 18; slightly over half of the entries have i< 19. For each object the catalog presents positions accurate to better than 0.1" rms per coordinate, five-band (ugriz) CCD-based photometry with typical accuracy of 0.03 mag, and information on the morphology and selection method. The catalog also contains radio, near-infrared, and X-ray emission properties of the quasars, when available, from other large-area surveys. The calibrated digital spectra cover the wavelength region 3800-9200 Ang. at a spectral resolution R = 2000 the spectra can be retrieved from the SDSS public database using the information provided in the catalog. Over 96% of the objects in the catalog were discovered by the SDSS. We also include a supplemental list of an additional 207 quasars with SDSS spectra whose archive photometric information is incomplete.Comment: Accepted, to appear in AJ, 7 figures, electronic version of Table 2 is available, see http://www.sdss.org/dr7/products/value_added/qsocat_dr7.htm

    The Eighth Data Release of the Sloan Digital Sky Survey: First Data from SDSS-III

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    The Sloan Digital Sky Survey (SDSS) started a new phase in August 2008, with new instrumentation and new surveys focused on Galactic structure and chemical evolution, measurements of the baryon oscillation feature in the clustering of galaxies and the quasar Ly alpha forest, and a radial velocity search for planets around ~8000 stars. This paper describes the first data release of SDSS-III (and the eighth counting from the beginning of the SDSS). The release includes five-band imaging of roughly 5200 deg^2 in the Southern Galactic Cap, bringing the total footprint of the SDSS imaging to 14,555 deg^2, or over a third of the Celestial Sphere. All the imaging data have been reprocessed with an improved sky-subtraction algorithm and a final, self-consistent photometric recalibration and flat-field determination. This release also includes all data from the second phase of the Sloan Extension for Galactic Understanding and Evolution (SEGUE-2), consisting of spectroscopy of approximately 118,000 stars at both high and low Galactic latitudes. All the more than half a million stellar spectra obtained with the SDSS spectrograph have been reprocessed through an improved stellar parameters pipeline, which has better determination of metallicity for high metallicity stars.Comment: Astrophysical Journal Supplements, in press (minor updates from submitted version

    Safety and Reactogenicity of Canarypox ALVAC-HIV (vCP1521) and HIV-1 gp120 AIDSVAX B/E Vaccination in an Efficacy Trial in Thailand

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    A prime-boost vaccination regimen with ALVAC-HIV (vCP1521) administered intramuscularly at 0, 4, 12, and 24 weeks and gp120 AIDSVAX B/E at 12 and 24 weeks demonstrated modest efficacy of 31.2% for prevention of HIV acquisition in HIV-uninfected adults participating in a community-based efficacy trial in Thailand.Reactogenicity was recorded for 3 days following vaccination. Adverse events were monitored every 6 months for 3.5 years, during which pregnancy outcomes were recorded. Of the 16,402 volunteers, 69% of the participants reported an adverse event any time after the first dose. Only 32.9% experienced an AE within 30 days following any vaccination. Overall adverse event rates and attribution of relatedness did not differ between groups. The frequency of serious adverse events was similar in vaccine (14.3%) and placebo (14.9%) recipients (p = 0.33). None of the 160 deaths (85 in vaccine and 75 in placebo recipients, p = 0.43) was assessed as related to vaccine. The most common cause of death was trauma or traffic accident. Approximately 30% of female participants reported a pregnancy during the study. Abnormal pregnancy outcomes were experienced in 17.1% of vaccine and 14.6% (p = 0.13) of placebo recipients. When the conception occurred within 3 months (estimated) of a vaccination, the majority of these abnormal outcomes were spontaneous or elective abortions among 22.2% and 15.3% of vaccine and placebo pregnant recipients, respectively (p = 0.08). Local reactions occurred in 88.0% of vaccine and 61.0% of placebo recipients (p<0.001) and were more frequent after ALVAC-HIV than AIDSVAX B/E vaccination. Systemic reactions were more frequent in vaccine than placebo recipients (77.2% vs. 59.8%, p<0.001). Local and systemic reactions were mostly mild to moderate, resolving within 3 days.The ALVAC-HIV and AIDSVAX B/E vaccine regimen was found to be safe, well tolerated and suitable for potential large-scale use in Thailand.ClinicalTrials.govNCT00223080

    Early Low-Titer Neutralizing Antibodies Impede HIV-1 Replication and Select for Virus Escape

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    Single genome sequencing of early HIV-1 genomes provides a sensitive, dynamic assessment of virus evolution and insight into the earliest anti-viral immune responses in vivo. By using this approach, together with deep sequencing, site-directed mutagenesis, antibody adsorptions and virus-entry assays, we found evidence in three subjects of neutralizing antibody (Nab) responses as early as 2 weeks post-seroconversion, with Nab titers as low as 1∶20 to 1∶50 (IC50) selecting for virus escape. In each of the subjects, Nabs targeted different regions of the HIV-1 envelope (Env) in a strain-specific, conformationally sensitive manner. In subject CH40, virus escape was first mediated by mutations in the V1 region of the Env, followed by V3. HIV-1 specific monoclonal antibodies from this subject mapped to an immunodominant region at the base of V3 and exhibited neutralizing patterns indistinguishable from polyclonal antibody responses, indicating V1–V3 interactions within the Env trimer. In subject CH77, escape mutations mapped to the V2 region of Env, several of which selected for alterations of glycosylation. And in subject CH58, escape mutations mapped to the Env outer domain. In all three subjects, initial Nab recognition was followed by sequential rounds of virus escape and Nab elicitation, with Nab escape variants exhibiting variable costs to replication fitness. Although delayed in comparison with autologous CD8 T-cell responses, our findings show that Nabs appear earlier in HIV-1 infection than previously recognized, target diverse sites on HIV-1 Env, and impede virus replication at surprisingly low titers. The unexpected in vivo sensitivity of early transmitted/founder virus to Nabs raises the possibility that similarly low concentrations of vaccine-induced Nabs could impair virus acquisition in natural HIV-1 transmission, where the risk of infection is low and the number of viruses responsible for transmission and productive clinical infection is typically one

    The importance of nerve microenvironment for schwannoma development

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    Schwannomas are predominantly benign nerve sheath neoplasms caused by Nf2 gene inactivation. Presently, treatment options are mainly limited to surgical tumor resection due to the lack of effective pharmacological drugs. Although the mechanistic understanding of Nf2 gene function has advanced, it has so far been primarily restricted to Schwann cell-intrinsic events. Extracellular cues determining Schwann cell behavior with regard to schwannoma development remain unknown. Here we show pro-tumourigenic microenvironmental effects on Schwann cells where an altered axonal microenvironment in cooperation with injury signals contribute to a persistent regenerative Schwann cell response promoting schwannoma development. Specifically in genetically engineered mice following crush injuries on sciatic nerves, we found macroscopic nerve swellings in mice with homozygous nf2 gene deletion in Schwann cells and in animals with heterozygous nf2 knockout in both Schwann cells and axons. However, patient-mimicking schwannomas could only be provoked in animals with combined heterozygous nf2 knockout in Schwann cells and axons. We identified a severe re-myelination defect and sustained macrophage presence in the tumor tissue as major abnormalities. Strikingly, treatment of tumor-developing mice after nerve crush injury with medium-dose aspirin significantly decreased schwannoma progression in this disease model. Our results suggest a multifactorial concept for schwannoma formation-emphasizing axonal factors and mechanical nerve irritation as predilection site for schwannoma development. Furthermore, we provide evidence supporting the potential efficacy of anti-inflammatory drugs in the treatment of schwannomas

    A prenylated dsRNA sensor protects against severe COVID-19

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    Inherited genetic factors can influence the severity of COVID-19, but the molecular explanation underpinning a genetic association is often unclear. Intracellular antiviral defenses can inhibit the replication of viruses and reduce disease severity. To better understand the antiviral defenses relevant to COVID-19, we used interferon-stimulated gene (ISG) expression screening to reveal that OAS1, through RNase L, potently inhibits SARS-CoV-2. We show that a common splice-acceptor SNP (Rs10774671) governs whether people express prenylated OAS1 isoforms that are membrane-associated and sense specific regions of SARS-CoV-2 RNAs, or only express cytosolic, nonprenylated OAS1 that does not efficiently detect SARS-CoV-2. Importantly, in hospitalized patients, expression of prenylated OAS1 was associated with protection from severe COVID-19, suggesting this antiviral defense is a major component of a protective antiviral response

    Acute pancreatitis and fulminant hepatic failure

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    Background: The association of acute pancreatitis with fulminant hepatic failure (FHF) was first recognized in 1973. Since then, few studies have described the clinical profile of the FHF patient with acute pancreatitis. Identification of the distinguishing attributes of pancreatitis in combination with FHF will provide a more sound basis for clinical management. The purposes of this study were to identify distinguishing clinical characteristics of acute pancreatitis in FHF and to compare outcomes with those of patients with acutely decompensated chronic liver disease and acute pancreatitis (DECOMP). Study Design: This was a retrospective survey of 30 patients with FHF and 30 with DECOMP admitted during the period July 1995 to July 1997. Results: The prevalence of acute pancreatitis in FHF and DECOMP was 33% and 23%, respectively. Acute pancreatitis was associated with severe hepatocellular synthetic dysfunction, renal insufficiency, requirement for endotracheal intubation, increased acuity of illness at the time of ICU admission, more rapid decompensation during the disease, and significantly greater mortality in both the FHF and DECOMP groups. Conclusions: In both FHF and DECOMP, acute pancreatitis increases disease acuity and mortality. Acute pancreatitis does not occur with significantly greater frequency in FHE. Implementation of orthotopic liver transplantation may not be warranted in this setting

    Reduced transfusion requirements during major hepatic resection with use of intraoperative isovolemic hemodilution

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    BACKGROUND: Allogeneic blood transfusion during liver resection for malignancies has been associated with an increased incidence of tumor recurrence and decreased survival in some series. Isovolemic hemodilution (IH) has been utilized in cardiac, orthopedic, and major general surgery procedures to reduce the use of banked blood products. We therefore sought to determine the safety and efficacy of IH during major hepatic resection in an adult population. METHODS: Thirteen consecutive patients undergoing major hepatic resection with IH were compared with 13 age- and disease-matched controls. The diseases included metastatic colorectal adenocarcinoma (8 versus 9), hepatoma (2 in each group) and other (3 versus 2); and the procedures included total (right or left) hepatic lobectomy (8 versus 11), partial lobectomy (3 versus 1) and trisegmentectomy (2 versus 1). RESULTS: There was no significant difference in operating time, estimated blood loss, fresh frozen plasma, platelets, amount of crystalloid or colloid infused between the two groups. There was no perioperative morbidity related to IH. The use of IH resulted in a 60% reduction in mean packed red blood cells transfusion during major hepatic resection. Only 38% of patients undergoing IH required packed red cells transfusion, whereas 77% of historical control patients required allogenic transfusion. CONCLUSION: The use of IH reduces the need for homologous transfusion during major hepatic resection. IH is a safe technique during hepatic resection and is not associated with perioperative morbidity

    Outcomes of laparoscopic donor nephrectomy in obese patients

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    The applicability of laparoscopic donor nephrectomy (LDN) has not been assessed in the obese donor. We hypothesized that obesity is not a technical contraindication to LDN. From May 1998 to February 1999, 40 patients underwent LDN at the Georgetown Transplant Institute with the transperitoneal technique. Prophylaxis against deep venous thrombosis consisted of venous compression stockings, low-molecular weight heparin in obese patients, and early ambulation. The following variables were examined: donor sex, age, weight, height, related versus nonrelated donation, body mass index (BMI; wt/ht2), operating room time, estimated blood loss, length of stay, time out of work, and complications. BMI\u3e31 indicates morbid obesity, BMI\u3e27 indicates \u3e20% over ideal body weight, and normal BMI is 25. The patients were divided into nonobese (BMI≤31) and obese groups (BMI\u3e31). The two groups do not differ in outcome after LDN. Our data indicate that obesity is not associated with increased morbidity or mortality after LDN
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