2,347 research outputs found
Molecular detection of culture-confirmed bacterial bloodstream infections with limited enrichment time
Conventional blood culturing using automated instrumentation with phenotypic identification requires a significant amount of time to generate results. This study investigated the speed and accuracy of results generated using PCR and pyrosequencing compared to the time required to obtain Gram stain results and final culture identification for cases of culture-confirmed bloodstream infections. Research and physician-ordered blood cultures were drawn concurrently. Aliquots of the incubating research blood culture fluid were removed hourly between 5 and 8 h, at 24 h, and again at 5 days. DNA was extracted from these 6 time point aliquots and analyzed by PCR and pyrosequencing for bacterial rRNA gene targets. These results were then compared to those of the physician-ordered blood culture. PCR and pyrosequencing accurately identified 92% of all culture-confirmed cases after a mean enrichment time of 5.8 ± 2.9 h. When the time needed to complete sample processing was included for PCR and pyrosequencing protocols, the molecular approach yielded results in 11.8 ± 2.9 h compared to means of 27.9 ± 13.6 h to obtain the Gram stain results and 81.6 ± 24.0 h to generate the final culture-based identification. The molecular approach enabled accurate detection of most bacteria present in incubating blood culture bottles on average about 16 h sooner than Gram stain results became available and approximately 3 days sooner than the phenotypic identification was entered in the Laboratory Information System. If implemented, this more rapid molecular approach could minimize the number of doses of unnecessary or ineffective antibiotics administered to patients
The sizes of mini-voids in the local universe: an argument in favor of a warm dark matter model?
Using high-resolution simulations within the Cold and Warm Dark Matter models
we study the evolution of small scale structure in the Local Volume, a sphere
of 8 Mpc radius around the Local Group. We compare the observed spectrum of
mini-voids in the Local Volume with the spectrum of mini-voids determined from
the simulations. We show that the \LWDM model can easily explain both the
observed spectrum of mini-voids and the presence of low-mass galaxies observed
in the Local Volume, provided that all haloes with circular velocities greater
than 20 km/s host galaxies. On the contrary within the LCDM model the
distribution of the simulated mini-voids reflects the observed one if haloes
with maximal circular velocities larger than 35 km/s host galaxies. This
assumption is in contradiction with observations of galaxies with circular
velocities as low as 20 km/s in our Local Universe. A potential problem of the
LWDM model could be the late formation of the haloes in which the gas can be
efficiently photo-evaporated. Thus star formation is suppressed and low-mass
haloes might not host any galaxy at all.Comment: 13 pages, 10 figures, version 2, subsection 3.1 added, accepted to
MNRA
The Endosome Localized Arf-GAP AGAP1 Modulates Dendritic Spine Morphology Downstream of the Neurodevelopmental Disorder Factor Dysbindin
AGAP1 is an Arf1 GTPase activating protein that interacts with the vesicle-associated protein complexes adaptor protein 3 (AP-3) and Biogenesis of Lysosome Related Organelles Complex-1 (BLOC-1). Overexpression of AGAP1 in non-neuronal cells results in an accumulation of endosomal cargoes, which suggests a role in endosome-dependent traffic. In addition, AGAP1 is a candidate susceptibility gene for two neurodevelopmental disorders, autism spectrum disorder (ASD) and schizophrenia (SZ); yet its localization and function in neurons have not been described. Here, we describe that AGAP1 localizes to axons, dendrites, dendritic spines, and synapses, colocalizing preferentially with markers of early and recycling endosomes. Functional studies reveal overexpression and down-regulation of AGAP1 affects both neuronal endosomal trafficking and dendritic spine morphology, supporting a role for AGAP1 in the recycling endosomal trafficking involved in their morphogenesis. Finally, we determined the sensitivity of AGAP1 expression to mutations in the DTNBP1 gene, which is associated with neurodevelopmental disorder, and found that AGAP1 mRNA and protein levels are selectively reduced in the null allele of the mouse orthologue of DTNBP1. We postulate that endosomal trafficking contributes to the pathogenesis of neurodevelopmental disorders affecting dendritic spine morphology, and thus excitatory synapse structure and function
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Life-Expectancy Disparities Among Adults With HIV in the United States and Canada: The Impact of a Reduction in Drug- and Alcohol-Related Deaths Using the Lives Saved Simulation Model.
Improvements in life expectancy among people living with human immunodeficiency virus (PLWH) receiving antiretroviral treatment in the United States and Canada might differ among key populations. Given the difference in substance use among key populations and the current opioid epidemic, drug- and alcohol-related deaths might be contributing to the disparities in life expectancy. We sought to estimate life expectancy at age 20 years in key populations (and their comparison groups) in 3 time periods (2004-2007, 2008-2011, and 2012-2015) and the potential increase in expected life expectancy with a simulated 20% reduction in drug- and alcohol-related deaths using the novel Lives Saved Simulation model. Among 92,289 PLWH, life expectancy increased in all key populations and comparison groups from 2004-2007 to 2012-2015. Disparities in survival of approximately a decade persisted among black versus white men who have sex with men and people with (vs. without) a history of injection drug use. A 20% reduction in drug- and alcohol-related mortality would have the greatest life-expectancy benefit for black men who have sex with men, white women, and people with a history of injection drug use. Our findings suggest that preventing drug- and alcohol-related deaths among PLWH could narrow disparities in life expectancy among some key populations, but other causes of death must be addressed to further narrow the disparities
Pedagogy of hate
Written as an extended review of Peter McLaren’s 'Pedagogy of Insurrection: from Resurrection to Revolution’ published in 2015, this paper contradicts McLaren’s affirmation of political religion and the version of critical pedagogy on which it is based, claiming hate rather than Christian love as a core concept of Critical Theory. Not a personal, psychological or pathological hate, but a radical hate for what the world has become, or absolute negativity. Hate must be invoked as love-hate for the magic of dialectics to work against the holy love of McLaren’s Christian socialism. Radical hate reveals the main transcendental tenets of capitalist civilisation: God and Money, as impersonal forms of social domination that must be brought down to earth so real existence can learn, learn, learn itself. That is the educative power of the Pedagogy of Hate. Now and forever
Substructures in lens galaxies: PG1115+080 and B1555+375, two fold configurations
We study the anomalous flux ratio which is observed in some four-image lens
systems, where the source lies close to a fold caustic. In this case two of the
images are close to the critical curve and their flux ratio should be equal to
unity, instead in several cases the observed value differs significantly. The
most plausible solution is to invoke the presence of substructures, as for
instance predicted by the Cold Dark Matter scenario, located near the two
images. In particular, we analyze the two fold lens systems PG1115+080 and
B1555+375, for which there are not yet satisfactory models which explain the
observed anomalous flux ratios. We add to a smooth lens model, which reproduces
well the positions of the images but not the anomalous fluxes, one or two
substructures described as singular isothermal spheres. For PG1115+080 we
consider a smooth model with the influence of the group of galaxies described
by a SIS and a substructure with mass as well as a
smooth model with an external shear and one substructure with mass . For B1555+375 either a strong external shear or two substructures
with mass reproduce the data quite well.Comment: 26 pages, updated bibliography, Accepted for publication in
Astrophysics & Space Scienc
PG 1115+080: variations of the A2/A1 flux ratio and new values of the time delays
We report the results of our multicolor observations of PG 1115+080 with the
1.5-m telescope of the Maidanak Observatory (Uzbekistan, Central Asia) in
2001-2006. Monitoring data in filter R spanning the 2004, 2005 and 2006 seasons
(76 data points) demonstrate distinct brightness variations of the source
quasar with the total amplitude of almost 0.4 mag. Our R light curves have
shown image C leading B by 16.4d and image (A1+A2) by 12d that is inconsistent
with the previous estimates obtained by Schechter et al. in 1997 - 24.7d
between B and C and 9.4d between (A1+A2) and C. The new values of time delays
in PG 1115+080 must result in larger values for the Hubble constant, thus
reducing difference between its estimates taken from the gravitational lenses
and with other methods. Also, we analyzed variability of the A2/A1 flux ratio,
as well as color changes in the archetypal "fold" lens PG 1115+080. We found
the A1/A2 flux ratio to grow during 2001-2006 and to be larger at longer
wavelengths. In particular, the A2/A1 flux ratio reached 0.85 in filter I in
2006. We also present evidence that both the A1 and A2 images might have
undergone microlensing during 2001-2006, with the descending phase for A1 and
initial phase for A2. We find that the A2/A1 flux ratio anomaly in PG 1115 can
be well explained both by microlensing and by finite distance of the source
quasar from the caustic fold.Comment: 14 pages, 7 figures, 8 tables, Accepted for publication in MNRA
Theory of excited state absorptions in phenylene-based -conjugated polymers
Within a rigid-band correlated electron model for oligomers of
poly-(paraphenylene) (PPP) and poly-(paraphenylenevinylene) (PPV), we show that
there exist two fundamentally different classes of two-photon A states in
these systems to which photoinduced absorption (PA) can occur. At relatively
lower energies there occur A states which are superpositions of one
electron - one hole (1e--1h) and two electron -- two hole (2e--2h) excitations,
that are both comprised of the highest delocalized valence band and the lowest
delocalized conduction band states only. The dominant PA is to one specific
member of this class of states (the mA). In addition to the above class of
A states, PA can also occur to a higher energy kA state whose 2e--2h
component is {\em different} and has significant contributions from excitations
involving both delocalized and localized bands. Our calculated scaled energies
of the mA and the kA agree reasonably well to the experimentally
observed low and high energy PAs in PPV. The calculated relative intensities of
the two PAs are also in qualitative agreement with experiment. In the case of
ladder-type PPP and its oligomers, we predict from our theoretical work a new
intense PA at an energy considerably lower than the region where PA have been
observed currently. Based on earlier work that showed that efficient
charge--carrier generation occurs upon excitation to odd--parity states that
involve both delocalized and localized bands, we speculate that it is the
characteristic electronic nature of the kA that leads to charge generation
subsequent to excitation to this state, as found experimentally.Comment: Revtex4 style, 2 figures inserted in the text, three tables, 10 page
A Measurement of the Ds+ Lifetime
A high statistics measurement of the Ds+ lifetime from the Fermilab
fixed-target FOCUS photoproduction experiment is presented. We describe the
analysis of the two decay modes, Ds+ -> phi(1020)pi+ and Ds+ ->
\bar{K}*(892)0K+, used for the measurement. The measured lifetime is 507.4 +/-
5.5 (stat.) +/- 5.1 (syst.) fs using 8961 +/- 105 Ds+ -> phi(1020)pi+ and 4680
+/- 90 Ds+ -> \bar{K}*(892)0K+ decays. This is a significant improvement over
the present world average.Comment: 5 pages, 3 figures, 2 tables, submitted to PR
Search for and Using Genetic Programming Event Selection
We apply a genetic programming technique to search for the double Cabibbo
suppressed decays and .
We normalize these decays to their Cabibbo favored partners and find
\Lambda_c^+ \to p K^+ \pi^-\Lambda_c^+ \to p K^-
\pi^+ and D_s^+ \to K^+ K^+
\pi^-D_s^+ \to K^+ K^- \pi^+ where
the first errors are statistical and the second are systematic. Expressed as
90% confidence levels (CL), we find and respectively.
This is the first successful use of genetic programming in a high energy
physics data analysis.Comment: 10 page
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