298 research outputs found
Challenges in the development of the Laser Metal Deposition process for use in microgravity at the Einstein-Elevator
This paper is about the challenges in developing the Laser Metal Deposition process with metal powder for use in microgravity. The modified gravitational conditions are set up for a few seconds using a drop tower, the Einstein-Elevator of the Leibniz University Hannover. In addition to the drop tower, the specially adapted setup of the experiment will be explained. The samples produced in microgravity during this project will demonstrate the influence of gravity on this additive manufacturing process and on the materials used. Thermal analyses using the Ansys software show how the temperature distribution of the manufactured specimens looks over time and what this means for the execution of the experiment
Take-over expectation and criticality in Level 3 automated driving: a test track study on take-over behavior in semi-trucks
With the introduction of advanced driving assistance systems managing longitudinal and lateral control, conditional automated driving is seemingly in near future of series vehicles. While take-over behavior in the passenger car context has been investigated intensively in recent years, publications on semi-trucks with professional drivers are sparse. The effects influencing expert drivers during take-overs in this context lack thorough investigation and are required to design systems that facilitate safe take-overs. While multiple findings seem to cohere in passenger cars and semi-trucks, these findings rely on simulated studies without taking environments as found in the real world into account. A test track study was conducted, simulating highway driving with 27 professional non-affiliated truck drivers. The participants drove an automated Level 3 semi-truck while a non-driving-related task was available. Multiple time critical take-over situations were initiated during the drives to investigate four main objectives regarding driver behavior. (1) With these results, comparison of reaction times and behavior can be drawn to previous simulator studies. The effect of situation criticality (2) and training (3) of take-over situations is investigated. (4) The influence of warning expectation on driver behavior is explored. Results obtained displayed very quick time to hands on steering and time to first reaction all under 2.4 s. Highly critical situations generate very quick reaction times M = 0.81 s, while the manipulation of expectancy yielded no significant variation in reaction times. These reaction times serve as a reference of what can be expected from drivers under optimal take-over conditions, with quick reactions at high speed in critical situations
Predicting Survival for Veno-Arterial ECMO Using Conditional Inference Trees-A Multicenter Study
BACKGROUND
Despite increasing use and understanding of the process, veno-arterial extracorporeal membrane oxygenation (VA-ECMO) therapy is still associated with considerable mortality. Personalized and quick survival predictions using machine learning methods can assist in clinical decision making before ECMO insertion.
METHODS
This is a multicenter study to develop and validate an easy-to-use prognostic model to predict in-hospital mortality of VA-ECMO therapy, using unbiased recursive partitioning with conditional inference trees. We compared two sets with different numbers of variables (small and comprehensive), all of which were available just before ECMO initiation. The area under the curve (AUC), the cross-validated Brier score, and the error rate were applied to assess model performance. Data were collected retrospectively between 2007 and 2019.
RESULTS
837 patients were eligible for this study; 679 patients in the derivation cohort (median (IQR) age 60 (49 to 69) years; 187 (28%) female patients) and a total of 158 patients in two external validation cohorts (median (IQR) age 57 (49 to 65) and 70 (63 to 76) years). For the small data set, the model showed a cross-validated error rate of 35.79% and an AUC of 0.70 (95% confidence interval from 0.66 to 0.74). In the comprehensive data set, the error rate was the same with a value of 35.35%, with an AUC of 0.71 (95% confidence interval from 0.67 to 0.75). The mean Brier scores of the two models were 0.210 (small data set) and 0.211 (comprehensive data set). External validation showed an error rate of 43% and AUC of 0.60 (95% confidence interval from 0.52 to 0.69) using the small tree and an error rate of 35% with an AUC of 0.63 (95% confidence interval from 0.54 to 0.72) using the comprehensive tree. There were large differences between the two validation sets.
CONCLUSIONS
Conditional inference trees are able to augment prognostic clinical decision making for patients undergoing ECMO treatment. They may provide a degree of accuracy in mortality prediction and prognostic stratification using readily available variables
Telehealth and Mobile Health Applied To IntegratedBehavioral Care: OpportunitiesFor Progress In New Hampshire
This paper is an accompanying document to a webinar delivered on May 16, 2017, for the New Hampshire Citizens Health Initiative (Initiative). As integrated behavioral health efforts in New Hampshire gain traction, clinicians, administrators, payers, and policy makers are looking for additional efficiencies in delivering high quality healthcare. Telehealth and mobile health (mHealth) have the opportunity to help achieve this while delivering a robust, empowered patient experience.
The promise of video-based technology was first made in 1964 as Bell Telephone shared its Picturephone® with the world. This was the first device with audio and video delivered in an integrated technology platform. Fast-forward to today with Skype, FaceTime, and webinar tools being ubiquitous in our personal and business lives, but often slow to be adopted in the delivery of medicine.
Combining technology-savvy consumers with New Hampshire’s high rate of electronic health record (EHR) technology adoption, a fairly robust telecommunications infrastructure, and a predominately rural setting, there is strong foundation for telehealth and mHealth expansion in New Hampshire’s integrated health continuum
Integrating Behavioral Health & Primary Care in New Hampshire: A Path Forward to Sustainable Practice & Payment Transformation
New Hampshire residents face challenges with behavioral and physical health conditions and the interplay between them. National studies show the costs and the burden of illness from behavioral health conditions and co-occurring chronic health conditions that are not adequately treated in either primary care or behavioral health settings. Bringing primary health and behavioral health care together in integrated care settings can improve outcomes for both behavioral and physical health conditions. Primary care integrated behavioral health works in conjunction with specialty behavioral health providers, expanding capacity, improving access, and jointly managing the care of patients with higher levels of acuity
In its work to improve the health of NH residents and create effective and cost-effective systems of care, the NH Citizens Health Initiative (Initiative) created the NH Behavioral Health Integration Learning Collaborative (BHI Learning Collaborative) in November of 2015, as a project of its Accountable Care Learning Network (NHACLN). Bringing together more than 60 organizations, including providers of all types and sizes, all of the state’s community mental health centers, all of the major private and public insurers, and government and other stakeholders, the BHI Learning Collaborative built on earlier work of a NHACLN Workgroup focused on improving care for depression and co-occurring chronic illness. The BHI Learning Collaborative design is based on the core NHACLN philosophy of “shared data and shared learning” and the importance of transparency and open conversation across all stakeholder groups.
The first year of the BHI Learning Collaborative programming included shared learning on evidence-based practice for integrated behavioral health in primary care, shared data from the NH Comprehensive Healthcare Information System (NHCHIS), and work to develop sustainable payment models to replace inadequate Fee-for-Service (FFS) revenues. Provider members joined either a Project Implementation Track working on quality improvement projects to improve their levels of integration or a Listen and Learn Track for those just learning about Behavioral Health Integration (BHI). Providers in the Project Implementation Track completed a self-assessment of levels of BHI in their practice settings and committed to submit EHR-based clinical process and outcomes data to track performance on specified measures. All providers received access to unblinded NHACLN Primary Care and Behavioral Health attributed claims data from the NHCHIS for provider organizations in the NH BHI Learning Collaborative.
Following up on prior work focused on developing a sustainable model for integrating care for depression and co-occurring chronic illness in primary care settings, the BHI Learning Collaborative engaged consulting experts and participants in understanding challenges in Health Information Technology and Exchange (HIT/HIE), privacy and confidentiality, and workforce adequacy. The BHI Learning Collaborative identified a sustainable payment model for integrated care of depression in primary care. In the process of vetting the payment model, the BHI Learning Collaborative also identified and explored challenges in payment for Substance Use Disorder Screening, Brief Intervention and Referral to Treatment (SBIRT). New Hampshire’s residents will benefit from a health care system where primary care and behavioral health are integrated to support the care of the whole person. New Hampshire’s current opiate epidemic accentuates the need for better screening for behavioral health issues, prevention, and treatment referral integrated into primary care. New Hampshire providers and payers are poised to move towards greater integration of behavioral health and primary care and the Initiative looks forward to continuing to support progress in supporting a path to sustainable integrated behavioral and primary care
Pumpless Extracorporeal Hemadsorption Technique (pEHAT) : A Proof-of-Concept Animal Study
Background: Extracorporeal hemadsorption eliminates proinflammatory mediators in
critically ill patients with hyperinflammation. The use of a pumpless extracorporeal hemadsorption
technique allows its early usage prior to organ failure and the need for an additional medical device.
In our animal model, we investigated the feasibility of pumpless extracorporeal hemadsorption over a
wide range of mean arterial pressures (MAP). Methods: An arteriovenous shunt between the femoral
artery and femoral vein was established in eight pigs. The hemadsorption devices were inserted into
the shunt circulation; four pigs received CytoSorb® and four Oxiris® hemadsorbers. Extracorporeal
blood flow was measured in a range between mean arterial pressures of 45–85 mmHg. Mean arterial
pressures were preset using intravenous infusions of noradrenaline, urapidil, or increased sedatives.
Results: Extracorporeal blood flows remained well above the minimum flows recommended by the
manufacturers throughout all MAP steps for both devices. Linear regression resulted in CytoSorb®
blood flow [mL/min] = 4.226 × MAP [mmHg] − 3.496 (R-square 0.8133) and Oxiris® blood flow
[mL/min] = 3.267 × MAP [mmHg] + 57.63 (R-square 0.8708), respectively. Conclusion: Arteriovenous pumpless extracorporeal hemadsorption resulted in sufficient blood flows through both the
CytoSorb® and Oxiris® devices over a wide range of mean arterial blood pressures and is likely an
intriguing therapeutic option in the early phase of septic shock or hyperinflammatory syndromes
AEGIS: The Morphologies of Green Galaxies at 0.4<z<1.2
We present quantitative morphologies of ~300 galaxies in the
optically-defined green valley at 0.4<z<1.2, in order to constrain the
mechanism(s) responsible for quenching star formation in the bulk of this
population. The sample is selected from galaxies in the All-Wavelength Extended
Groth Strip International Survey (AEGIS). While the green valley is defined
using optical U-B colors, we find that using a green valley sample defined
using NUV-R colors does not change the results. Using HST/ACS imaging, we study
several quantitative morphological parameters including CAS, B/T from GIM2D,
and Gini/M_20. We find that the green galaxy population is intermediate between
the red and blue galaxy populations in terms of concentration, asymmetry, and
morphological type and merger fraction estimated using Gini/M_20. We find that
most green galaxies are not classified as mergers; in fact, the merger fraction
in the green valley is lower than in the blue cloud. We show that at a given
stellar mass, green galaxies have higher concentration values than blue
galaxies and lower concentration values than red galaxies. Additionally, we
find that 12% of green galaxies have B/T = 0 and 21% with B/T \leq 0.05. Our
results show that green galaxies are generally massive (M\ast ~ 10^10.5 M_sun)
disk galaxies with high concentrations. We conclude that major mergers are
likely not the sole mechanism responsible for quenching star formation in this
population and that either other external processes or internal secular
processes play an important role both in driving gas towards the center of
these galaxies and in quenching star formation.Comment: Accepted to ApJ. in emulateapj style, 23 pages, 18 figures, 4 table
Emission-Line Galaxies from the Hubble Space Telescope Probing Evolution and Reionization Spectroscopically (PEARS) Grism Survey. II: The Complete Sample
We present a full analysis of the Probing Evolution And Reionization
Spectroscopically (PEARS) slitess grism spectroscopic data obtained with the
Advanced Camera for Surveys on HST. PEARS covers fields within both the Great
Observatories Origins Deep Survey (GOODS) North and South fields, making it
ideal as a random survey of galaxies, as well as the availability of a wide
variety of ancillary observations to support the spectroscopic results. Using
the PEARS data we are able to identify star forming galaxies within the
redshift volume 0< z<1.5. Star forming regions in the PEARS survey are
pinpointed independently of the host galaxy. This method allows us to detect
the presence of multiple emission line regions (ELRs) within a single galaxy.
1162 Ha, [OIII] and/or [OII] emission lines have been identified in the PEARS
sample of ~906 galaxies down to a limiting flux of ~1e-18 erg/s/cm^2. The ELRs
have also been compared to the properties of the host galaxy, including
morphology, luminosity, and mass. From this analysis we find three key results:
1) The computed line luminosities show evidence of a flattening in the
luminosity function with increasing redshift; 2) The star forming systems show
evidence of disturbed morphologies, with star formation occurring predominantly
within one effective (half-light) radius. However, the morphologies show no
correlation with host stellar mass; and 3) The number density of star forming
galaxies with M_* > 1e9} M_sun decreases by an order of magnitude at z<0.5
relative to the number at 0.5<z<0.9 in support of the argument for galaxy
downsizing.Comment: Submitted. 48 pages. 19 figures. Accepted to Ap
History of Galaxy Interactions and their Impact on Star Formation over the Last 7 Gyr from GEMS
We perform a comprehensive estimate of the frequency of galaxy mergers and
their impact on star formation over z~0.24--0.80 (lookback time T_b~3--7 Gyr)
using 3698 (M*>=1e9 Msun) galaxies with GEMS HST, COMBO-17, and Spitzer data.
Our results are: (1) Among 790 high mass (M*>=2.5e10 Msun) galaxies, the
visually-based merger fraction over z~0.24--0.80, ranges from 9%+-5% to 8%+-2%.
Lower limits on the major and minor merger fractions over this interval range
from 1.1% to 3.5%, and 3.6% to 7.5%, respectively. This is the first
approximate empirical estimate of the frequency of minor mergers at z<1. For a
visibility timescale of ~0.5 Gyr, it follows that over T_b~3--7 Gyr, ~68% of
high mass systems have undergone a merger of mass ratio >1/10, with ~16%, 45%,
and 7% of these corresponding respectively to major, minor, and ambiguous
`major or minor' mergers. The mean merger rate is a few x 1e-4 Gyr-1 Mpc-3. (2)
We compare the empirical merger fraction and rate for high mass galaxies to a
suite of Lambda CDM-based models: halo occupation distribution models,
semi-analytic models, and hydrodynamic SPH simulations. We find qualitative
agreement between observations and models such that the (major+minor) merger
fraction or rate from different models bracket the observations, and show a
factor of five dispersion. Near-future improvements can now start to rule out
certain merger scenarios. (3) Among ~3698 M*>=1e9 Msun galaxies, we find that
the mean SFR of visibly merging systems is only modestly enhanced compared to
non-interacting galaxies over z~0.24--0.80. Visibly merging systems only
account for less than 30% of the cosmic SFR density over T_b~3--7 Gyr. This
suggests that the behavior of the cosmic SFR density over the last 7 Gyr is
predominantly shaped by non-interacting galaxies.Comment: Accepted for Publication in the Astrophysical Journal. 17 pages of
text, 21 figures, 3 tables. Uses emulateapj5.st
Evidence for Three Accreting Black Holes in a Galaxy at z~1.35: A Snapshot of Recently Formed Black Hole Seeds?
One of the key open questions in cosmology today pertains to understanding
when, where and how super massive black holes form, while it is clear that
mergers likely play a significant role in the growth cycles of black holes, how
supermassive black holes form, and how galaxies grow around them. Here, we
present Hubble Space Telescope WFC3/IR grism observations of a clumpy galaxy at
z=1.35, with evidence for 10^6 - 10^7 Msun rapidly growing black holes in
separate sub-components of the host galaxy. These black holes could have been
brought into close proximity as a consequence of a rare multiple galaxy merger
or they could have formed in situ. Such holes would eventually merge into a
central black hole as the stellar clumps/components presumably coalesce to form
a galaxy bulge. If we are witnessing the in-situ formation of multiple black
holes, their properties can inform seed formation models and raise the
possibility that massive black holes can continue to emerge in star-forming
galaxies as late as z=1.35 (4.8 Gyr after the Big Bang).Comment: Accepted for publication in ApJ Letters. 6 pages, 4 figures, 1 tabl
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