1,723 research outputs found
Consistent Earnings Growth and the Credibility of Management Forecasts
This paper examines the relation between a series of past earnings increases and the credibility of voluntary management earnings forecasts. We demonstrate that both analyst forecast revisions and stock price reactions around management earnings forecasts that contain good news are more pronounced when the firm has posted a string of recent earnings increases. These results are consistent with our primary hypothesis that voluntary management earnings forecasts are more believable when they are made by firms with a history of consistent growth in earnings. This effect is more pronounced when firms are not widely followed by analysts. Additional analysis suggests that management forecasts are more accurate relative to ex post realized earnings when made by a firm with consistent growth in prior earnings. The effect of prior earnings growth on the credibility of management earnings forecasts is reduced when the level of net assets suggests a history of prior earnings management
Spike-timing control by dendritic plateau potentials in the presence of synaptic barrages
Apical and tuft dendrites of pyramidal neurons support regenerative electrical potentials, giving rise to long-lasting (approximately hundreds of milliseconds) and strong (~50 mV from rest) depolarizations. Such plateau events rely on clustered glutamatergic input, can be mediated by calcium or by NMDA currents, and often generate somatic depolarizations that last for the time course of the dendritic plateau event. We address the computational significance of such single-neuron processing via reduced but biophysically realistic modeling. We introduce a model based on two discrete integration zones, a somatic and a dendritic one, that communicate from the dendritic to the somatic compartment via a long plateau-conductance. We show principled differences in the way dendritic vs. somatic inhibition controls spike timing, and demonstrate how this could implement a mechanism of spike time control in the face of barrages of synaptic inputs
TurbuStat: Turbulence Statistics in Python
We present TurbuStat (v1.0): a Python package for computing turbulence
statistics in spectral-line data cubes. TurbuStat includes implementations of
fourteen methods for recovering turbulent properties from observational data.
Additional features of the software include: distance metrics for comparing two
data sets; a segmented linear model for fitting lines with a break-point; a
two-dimensional elliptical power-law model; multi-core fast-fourier-transform
support; a suite for producing simulated observations of fractional Brownian
Motion fields, including two-dimensional images and optically-thin HI data
cubes; and functions for creating realistic world coordinate system information
for synthetic observations. This paper summarizes the TurbuStat package and
provides representative examples using several different methods. TurbuStat is
an open-source package and we welcome community feedback and contributions.Comment: Accepted in AJ. 21 pages, 8 figure
Physiology of Layer 5 Pyramidal Neurons in Mouse Primary Visual Cortex: Coincidence Detection through Bursting
L5 pyramidal neurons are the only neocortical cell type with dendrites reaching all six layers of cortex, casting them as one of the main integrators in the cortical column. What is the nature and mode of computation performed in mouse primary visual cortex (V1) given the physiology of L5 pyramidal neurons? First, we experimentally establish active properties of the dendrites of L5 pyramidal neurons of mouse V1 using patch-clamp recordings. Using a detailed multi-compartmental model, we show this physiological setup to be well suited for coincidence detection between basal and apical tuft inputs by controlling the frequency of spike output. We further show how direct inhibition of calcium channels in the dendrites modulates such coincidence detection. To establish the singe-cell computation that this biophysics supports, we show that the combination of frequency-modulation of somatic output by tuft input and (simulated) calcium-channel blockage functionally acts as a composite sigmoidal function. Finally, we explore how this computation provides a mechanism whereby dendritic spiking contributes to orientation tuning in pyramidal neurons
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Light emission intensities of luminescent Y2O3:Eu and Gd2O3:Eu particles of various sizes
There is great technological interest in elucidating the effect of particle size on the luminescence efficiency of doped rare earth oxides. This study demonstrates unambiguously that there is a size effect and that it is not dependent on the calcination temperature. The Y2O3:Eu and Gd2O3:Eu particles used in this study were synthesized using wet chemistry to produce particles ranging in size between 7 nm and 326 nm and a commercially available phosphor. These particles were characterized using three excitation methods: UV light at 250 nm wavelength, electron beam at 10 kV, and X-rays generated at 100 kV. Regardless of the excitation source, it was found that with increasing particle diameter there is an increase in emitted light. Furthermore, dense particles emit more light than porous particles. These results can be explained by considering the larger surface area to volume ratio of the smallest particles and increased internal surface area of the pores found in the large particles. For the small particles, the additional surface area hosts adsorbates that lead to non-radiative recombination, and in the porous particles, the pore walls can quench fluorescence. This trend is valid across calcination temperatures and is evident when comparing particles from the same calcination temperature
Litter identity affects assimilation of carbon and nitrogen by a shredding caddisfly
Ecologists often equate litter quality with decomposition rate. In soil and sediments, litter that is rapidly decomposed by microbes often has low concentrations of tannin and lignin and low C:N ratios. Do these same traits also favor element transfer to higher trophic levels in streams, where many insects depend on litter as their primary food source? We test the hypothesis that slow decomposition rates promote element transfer from litter to insects, whereas rapid decomposition favors microbes. We measured carbon and nitrogen fluxes from four plant species to a leaf-shredding caddisfly using isotopically labeled litter. Caddisflies assimilated a higher percentage of litter carbon and nitrogen lost from slowly decomposing litters (Platanus wrightii and Quercus gambelii). In contrast, rapidly decomposing litters (Fraxinus velutina and Populus fremontii) supported higher microbial biomass. These results challenge the view that rapidly decomposing litter is higher quality by demonstrating that slowly decomposing litters provide a critical resource for insects
A Prospective Program to Reduce the Clinical Incidence of Clostridium Difficile Colitis Infection after Cystectomy
Purpose
The development of Clostridium difficile infection after cystectomy is associated with significant morbidity and mortality. We implemented a prospective screening program to identify asymptomatic carriers of Clostridium difficile and assessed its impact on clinical Clostridium difficile infection rates compared to historical matched controls.
Materials and Methods
Prospective Clostridium Difficile screening prior to cystectomy began in March 2015. The 380 consecutive patients undergoing cystectomy prior to initiation of screening (control cohort) were matched based on 5 clinical factors with the 386 patients who underwent cystectomy from March 2015 to December 2017 (trial cohort). Screened positive patients were placed in contact isolation and treated prophylactically with Metronidazole. Multivariable models were built on an intention-to-screen and an effectiveness of screening basis to determine if screening reduced the rates of symptomatic Clostridium Difficile infections postoperatively.
Results
With the implementation of the screening protocol, Clostridium difficile infections rates declined from 9.4 to 5.5% (OR 0.52, p=0.0268) on an intention-to-screen protocol and from 9.2 to 4.9% on an effectiveness of screening protocol (OR 0.46, p=0.0174).
Conclusions
Clostridium difficile screening prior to cystectomy is associated with a significant decrease in rates of clinically symptomatic infections postoperatively. These results should be confirmed in a randomized controlled trial
Interventions to reduce stress and prevent burnout in healthcare professionals supported by digital applications: a scoping review
Aim: Healthcare professionals are at increased risk of burnout, primarily due to workplace-related stressors. The COVID-19 pandemic has further increased this risk. Different interventions exist with varying degrees of effectiveness; little is reported on the content and implementation of such programs. This review fills this gap, with attention to recent programs using digital components.
Methods: PubMed, Embase, PsycInfo, and Google Scholar were searched between January 24th and 28th, 2022, limited to the last 5 years (≥2017). Articles were included if they (1) focused on stress reduction or burnout prevention for nurses and medical doctors within workplace health promotion for nurses or medical doctors, (2) included a digital program component, (3) were conducted in high-income country contexts, and (4) were clinical studies published in English or German. Data was extracted using a priori designed spreadsheets. A group of at least 2 authors at each stage carried out the screening, selection, and data extraction.
Results: The search strategy identified 153 articles, all except 7 were excluded. Two studies were conducted in the USA, two in Spain, one in the Netherlands, Poland, and Korea each. Four studies used a randomized study design, all but one had a control group. A wide range of outcome measures was used. The types of interventions included an adapted mindfulness-based stress reduction program combined with aspects of behavioral therapies, cognitive behavioral therapy, or acceptance and commitment therapy. The digital components used were apps (4 studies), a digital platform, blended learning, and a web-based intervention (1 study each). Six studies focused on individual interventions, one included organizational interventions.
Conclusion: Despite an acute burnout crisis in the healthcare sector, only seven recent interventions were found that integrated digital components. Several problems emerged during the implementation of the interventions that made it clear that organizational support is urgently needed for successful implementation. Although interventions for stress reduction and burnout prevention should combine individual and organizational measures to be as successful as possible, this was only partially the case in one of the intervention programs. The results of this scoping review can be used to further develop or optimize stress and burnout prevention programs
The turbulent gas structure in the centers of NGC253 and the Milky Way
We compare molecular gas properties in the starbursting center of NGC253 and
the Milky Way Galactic Center (GC) on scales of ~1-100 pc using dendograms and
resolution-, area- and noise-matched datasets in CO (1-0) and CO (3-2). We find
that the size-line width relations in NGC253 and the GC have similar slope, but
NGC253 has larger line widths by factors of ~2-3. The dependency
on column density shows that, in the GC, on scales of 10-100 pc the kinematics
of gas over cm are compatible with gravitationally
bound structures. In NGC253 this is only the case for column densities
cm. The increased line widths in NGC253 originate in
the lower column density gas. This high-velocity dispersion, not
gravitationally self-bound gas is likely in transient structures created by the
combination of high average densities and feedback in the starburst. The high
densities turns the gas molecular throughout the volume of the starburst, and
the injection of energy and momentum by feedback significantly increases the
velocity dispersion at a given spatial scale over what is observed in the GC.Comment: 13 pages, 3 figures, 4 tables; accepted for publication in the
Astrophysical Journa
The Calcitonin and Glucocorticoids Combination: Mechanistic Insights into Their Class-Effect Synergy in Experimental Arthritis
PMCID: PMC3564948This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited
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