196 research outputs found

    Vortex: A new family of one-way hash functions based on AES rounds and carry-less multiplication

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    Abstract. We present Vortex a new family of one way hash functions that can produce message digests of 256 bits. The main idea behind the design of these hash functions is that we use well known algorithms that can support very fast diffusion in a small number of steps. We also balance the cryptographic strength that comes from iterating block cipher rounds with SBox substitution and diffusion (like Whirlpool) against the need to have a lightweight implementation with as small number of rounds as possible. We use only 3 AES rounds as opposed to 10 since our goal is not to protect a secret symmetric key but to support perfect mixing of the bits of the input into the hash value. Three AES rounds are followed by our variant of Galois Field multiplication. This achieves cross-mixing between 128-bit sets. We present a set of qualitative arguments why we believe Vortex supports collision resistance and first pre-image resistance

    Adverse Birth Outcomes of adolescent and Young adult Women Diagnosed With Cancer During Pregnancy

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    BACKGROUND: We examined adverse birth outcomes among adolescent and young adult women diagnosed with cancer (AYA women, ages 15-39 years) during pregnancy. METHODS: We linked data from the Texas Cancer Registry, vital records, and Texas Birth Defects Registry to identify all singleton births to AYA women diagnosed during pregnancy from January 1999 to December 2016. We compared prevalence of adverse live birth outcomes between AYA women and women without cancer (matched 1:4 on age, race and ethnicity, and year). Among AYA women, we used log-binomial regression to identify factors associated with these outcomes. Statistical tests were 2-sided. RESULTS: AYA women had 1271 singleton live births and 20 stillbirths. AYA women (n = 1291) were 33.3% Hispanic and 9.8% non-Hispanic Black and most commonly had breast (22.5%), thyroid (19.8%), and gynecologic (13.3%) cancers. Among live births, AYA women had a higher prevalence of low birth weight offspring (30.1% vs 9.0%), very preterm (5.7% vs 1.2%), and preterm birth (25.1% vs 7.2%); cesarean delivery (44.3% vs 35.2%); and low Apgar score (2.7% vs 1.5%), compared with women without cancer (n = 5084) (all P \u3c .05). Prevalence of any birth defect by age 12 months did not statistically differ (5.2% vs 4.7%; P = .48), but live births to AYA women more often had heart and circulatory system defects (2.2% vs 1.3%; P = .01). In adjusted models, cancer type and chemotherapy were associated with adverse live birth outcomes. CONCLUSIONS: AYA women diagnosed during pregnancy have higher prevalence of adverse birth outcomes and face difficult decisions in balancing treatment risks and benefits

    A Maturity Model for Operations in Neuroscience Research

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    Scientists are adopting new approaches to scale up their activities and goals. Progress in neurotechnologies, artificial intelligence, automation, and tools for collaboration promises new bursts of discoveries. However, compared to other disciplines and the industry, neuroscience laboratories have been slow to adopt key technologies to support collaboration, reproducibility, and automation. Drawing on progress in other fields, we define a roadmap for implementing automated research workflows for diverse research teams. We propose establishing a five-level capability maturity model for operations in neuroscience research. Achieving higher levels of operational maturity requires new technology-enabled methodologies, which we describe as ``SciOps''. The maturity model provides guidelines for evaluating and upgrading operations in multidisciplinary neuroscience teams.Comment: 10 pages, one figur

    Strategies for determining the cascade rate in MHD Turbulence: isotropy, anisotropy, and spacecraft sampling

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    Exact laws for evaluating cascade rates, tracing back to the Kolmogorov "4/5"law, have been extended to many systems of interest including magnetohydrodynamics (MHD), and compressible flows of the magnetofluid and ordinary fluid types. It is understood that implementations may be limited by the quantity of available data and by the lack of turbulence symmetry. Assessment of the accuracy and feasibility of such third-order (or Yaglom) relations is most effectively accomplished by examining the von Kármán-Howarth equation in increment form, a framework from which the third-order laws are derived as asymptotic approximations. Using this approach, we examine the context of third-order laws for incompressible MHD in some detail. The simplest versions rely on the assumption of isotropy and the presence of a well-defined inertial range, while related procedures generalize the same idea to arbitrary rotational symmetries. Conditions for obtaining correct and accurate values of the dissipation rate from these laws based on several sampling and fitting strategies are investigated using results from simulations. The questions we address are of particular relevance to sampling of solar wind turbulence by one or more spacecraft

    Systemic inflammatory response syndrome in adult patients with nosocomial bloodstream infections due to enterococci

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    BACKGROUND: Enterococci are the third leading cause of nosocomial bloodstream infection (BSI). Vancomycin resistant enterococci are common and provide treatment challenges; however questions remain about VRE's pathogenicity and its direct clinical impact. This study analyzed the inflammatory response of Enterococcal BSI, contrasting infections from vancomycin-resistant and vancomycin-susceptible isolates. METHODS: We performed a historical cohort study on 50 adults with enterococcal BSI to evaluate the associated systemic inflammatory response syndrome (SIRS) and mortality. We examined SIRS scores 2 days prior through 14 days after the first positive blood culture. Vancomycin resistant (n = 17) and susceptible infections (n = 33) were compared. Variables significant in univariate analysis were entered into a logistic regression model to determine the affect on mortality. RESULTS: 60% of BSI were caused by E. faecalis and 34% by E. faecium. 34% of the isolates were vancomycin resistant. Mean APACHE II (A2) score on the day of BSI was 16. Appropriate antimicrobials were begun within 24 hours in 52%. Septic shock occurred in 62% and severe sepsis in an additional 18%. Incidence of organ failure was as follows: respiratory 42%, renal 48%, hematologic 44%, hepatic 26%. Crude mortality was 48%. Progression to septic shock was associated with death (OR 14.9, p < .001). There was no difference in A2 scores on days -2, -1 and 0 between the VRE and VSE groups. Maximal SIR (severe sepsis, septic shock or death) was seen on day 2 for VSE BSI vs. day 8 for VRE. No significant difference was noted in the incidence of organ failure, 7-day or overall mortality between the two groups. Univariate analysis revealed that AP2>18 at BSI onset, and respiratory, cardiovascular, renal, hematologic and hepatic failure were associated with death, but time to appropriate therapy >24 hours, age, and infection due to VRE were not. Multivariate analysis revealed that hematologic (OR 8.4, p = .025) and cardiovascular failure (OR 7.5, p = 032) independently predicted death. CONCLUSION: In patients with enterococcal BSI, (1) the incidence of septic shock and organ failure is high, (2) patients with VRE BSI are not more acutely ill prior to infection than those with VSE BSI, and (3) the development of hematologic or cardiovascular failure independently predicts death

    Direct involvement of the TEN domain at the active site of human telomerase

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    Telomerase is a ribonucleoprotein that adds DNA to the ends of chromosomes. The catalytic protein subunit of telomerase (TERT) contains an N-terminal domain (TEN) that is important for activity and processivity. Here we describe a mutation in the TEN domain of human TERT that results in a greatly increased primer Kd, supporting a role for the TEN domain in DNA affinity. Measurement of enzyme kinetic parameters has revealed that this mutant enzyme is also defective in dNTP polymerization, particularly while copying position 51 of the RNA template. The catalytic defect is independent of the presence of binding interactions at the 5′-region of the DNA primer, and is not a defect in translocation rate. These data suggest that the TEN domain is involved in conformational changes required to position the 3′-end of the primer in the active site during nucleotide addition, a function which is distinct from the role of the TEN domain in providing DNA binding affinity
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