31,763 research outputs found
Elastic and plastic analysis of pressure vessel weld lands with mismatch
Elastic and plastic analysis of pressure vessel weld lands with mismatc
Elastic and plastic stresses at weld sinkages and other discontinuities in pressure vessels
Mismatch and weld sinkage problems of pressure vessel geometric discontinuities studied in design graphs and test progra
Bioinformatic Analyses of Unique (Orphan) Core Genes of the Genus Acidithiobacillus: Functional Inferences and Use As Molecular Probes for Genomic and Metagenomic/Transcriptomic Interrogation
IndexaciĂłn: Web of Science.Using phylogenomic and gene compositional analyses, five highly conserved gene families have been detected in the core genome of the phylogenetically coherent genus Acidithiobacillus of the class Acidithiobacillia. These core gene families are absent in the closest extant genus Thermithiobacillus tepidarius that subtends the Acidithiobacillus genus and roots the deepest in this class. The predicted proteins encoded by these core gene families are not detected by a BLAST search in the NCBI non-redundant database of more than 90 million proteins using a relaxed cut-off of 1.0e(-5). None of the five families has a clear functional prediction. However, bioinformatic scrutiny, using pI prediction, motif/domain searches, cellular location predictions, genomic context analyses, and chromosome topology studies together with previously published transcriptomic and proteomic data, suggests that some may have functions associated with membrane remodeling during cell division perhaps in response to pH stress. Despite the high level of amino acid sequence conservation within each family, there is sufficient nucleotide variation of the respective genes to permit the use of the DNA sequences to distinguish different species of Acidithiobacillus, making them useful additions to the armamentarium of tools for phylogenetic analysis. Since the protein families are unique to the Acidithiobacillus genus, they can also be leveraged as probes to detect the genus in environmental metagenomes and metatranscriptomes, including industrial biomining operations, and acid mine drainage (AMD).http://journal.frontiersin.org/article/10.3389/fmicb.2016.02035/ful
Encrypted statistical machine learning: new privacy preserving methods
We present two new statistical machine learning methods designed to learn on
fully homomorphic encrypted (FHE) data. The introduction of FHE schemes
following Gentry (2009) opens up the prospect of privacy preserving statistical
machine learning analysis and modelling of encrypted data without compromising
security constraints. We propose tailored algorithms for applying extremely
random forests, involving a new cryptographic stochastic fraction estimator,
and na\"{i}ve Bayes, involving a semi-parametric model for the class decision
boundary, and show how they can be used to learn and predict from encrypted
data. We demonstrate that these techniques perform competitively on a variety
of classification data sets and provide detailed information about the
computational practicalities of these and other FHE methods.Comment: 39 page
Glass transitions and shear thickening suspension rheology
We introduce a class of simple models for shear thickening and/ or `jamming'
in colloidal suspensions. These are based on schematic mode coupling theory
(MCT) of the glass transition, having a memory term that depends on a density
variable, and on both the shear stress and the shear rate. (Tensorial aspects
of the rheology, such as normal stresses, are ignored for simplicity.) We
calculate steady-state flow curves and correlation functions. Depending on
model parameters, we find a range of rheological behaviours, including
`S-shaped' flow curves, indicating discontinuous shear thickening, and
stress-induced transitions from a fluid to a nonergodic (jammed) state, showing
zero flow rate in an interval of applied stress. The shear thickening and
jamming scenarios that we explore appear broadly consistent with experiments on
dense colloids close to the glass transition, despite the fact that we ignore
hydrodynamic interactions. In particular, the jamming transition we propose is
conceptually quite different from various hydrodynamic mechanisms of shear
thickening in the literature, although the latter might remain pertinent at
lower colloid densities. Our jammed state is a stress-induced glass, but its
nonergodicity transitions have an analytical structure distinct from that of
the conventional MCT glass transition.Comment: 33 pages; 19 figure
Lung lobe torsion in adult and juvenile pugs
This cases series of 13 pugs with lung lobe torsion (LLT) is the largest case series of pugs in the literature and the first to compare dogs presenting before and after 12 months of age. Similar to previous case series, the median age of pugs with LLT was 17 months; however six dogs were under 12 months of age (3 of 13 were 11–13 weeks at presentation). There were no differences between the dogs that presented younger or older than 12 months old with respect to sex, neuter status, lung lobe affected, duration and nature of clinical signs, time alive after discharge, and complications. The juvenile onset may suggest that some dogs are inherently at risk of LLT. This is intriguing and important as LLT may not be an intuitive diagnosis in a juvenile brachycephalic animal, and practitioners should be aware of this unusual presentation
Jamming transitions in a schematic model of suspension rheology
We study the steady-state response to applied stress in a simple scalar model
of sheared colloids. Our model is based on a schematic (F2) model of the glass
transition, with a memory term that depends on both stress and shear rate. For
suitable parameters, we find transitions from a fluid to a nonergodic, jammed
state, showing zero flow rate in an interval of applied stress. Although the
jammed state is a glass, we predict that jamming transitions have an analytical
structure distinct from that of the conventional mode coupling glass
transition. The static jamming transition we discuss is also distinct from
hydrodynamic shear thickening.Comment: 7 pages; 3 figures; improved version with added references. Accepted
for publication in Europhysics Letter
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