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Harmonization of space-borne infra-red sensors measuring sea surface temperature
Sea surface temperature (SST) is observed by a constellation of sensors, and SST retrievals
are commonly combined into gridded SST analyses and climate data records (CDRs). Differential
biases between SSTs from different sensors cause errors in such products, including feature artefacts.
We introduce a new method for reducing differential biases across the SST constellation, by reconciling
the brightness temperature (BT) calibration and SST retrieval parameters between sensors. We use the
Advanced Along-Track Scanning Radiometer (AATSR) and the Sea and Land Surface Temperature
Radiometer (SLSTR) as reference sensors, and the Advanced Very High Resolution Radiometer
(AVHRR) of the MetOp-A mission to bridge the gap between these references. Observations across a
range of AVHRR zenith angles are matched with dual-view three-channel skin SST retrievals from
the AATSR and SLSTR. These skin SSTs act as the harmonization reference for AVHRR retrievals
by optimal estimation (OE). Parameters for the harmonized AVHRR OE are iteratively determined,
including BT bias corrections and observation error covariance matrices as functions of water-vapor
path. The OE SSTs obtained from AVHRR are shown to be closely consistent with the reference sensor
SSTs. Independent validation against drifting buoy SSTs shows that the AVHRR OE retrieval is stable
across the reference-sensor gap. We discuss that this method is suitable to improve consistency across
the whole constellation of SST sensors. The approach will help stabilize and reduce errors in future
SST CDRs, as well as having application to other domains of remote sensing
A Kidney Biopsy Simulation Training Program for Renal Fellows: Two Years of Results
Renal interventions could re-foster interest in Nephrology and attract more medical graduates. Percutaneous kidney biopsy (PKB) is an important diagnostic tool and should be taught through simulation. We initiated a PKB simulation training program and designed a 2-year study to examine its effect on the confidence level, the procedural competence and the satisfaction with this training of Nephrology fellows compared to historical controls. All fellows were consented and trained at UNMâs simulation center (BATCAVE) with a simulation training model (CAE Healthcare Blue PhantomTM). Traineesâ demographics and previous PKB experience were collected. We utilized pre-assigned readings, online videos and hands-on simulation practice. Performance of each trainee during each session was graded with a procedural competence evaluation form. Drs. JO and MER were present in all sessions and completed these forms. Each session lasted 1 to 1-1 1/2 h. Pre-and post-simulation surveys evaluated the participantsâ confidence level quantitatively on a 5-point Likert scale. All participants completed the satisfaction with PKB simulation experience scale (PKB-SSE). All three 1st and 2nd year renal fellows completed the simulation training in 2018 and two first year fellows completed the training in 2019. Independent of their previous experience on PKBs all renal fellows expressed a high level of satisfaction from their participation (4 to 5) and increased their confidence level. This yearâs trainees increased their performance level from 2 to 5 and from 1 to 5, respectively. PKB simulation may improve traineesâ confidence level and their satisfaction with the training. The procedural competence of the trainees on PKBs will be evaluated during the 2nd year of their fellowship and will be compared to the procedural competence of historical controls. We expect that the simulation training will reduce the discomfort and minimize the adverse PKB outcomes in patients undergoing PKB in UNMH
Setting Priorities for Space Research: Opportunities and Imperatives
This report represents the first phase of a study by a task group convened by the Space Studies Board to ascertain whether it should attempt to develop a methodology for recommending priorities among the various initiatives in space research (that is, scientific activities concerned with phenomena in space or utilizing observations from space). The report argues that such priority statements by the space research community are both necessary and desirable and would contribute to the formulation and implementation of public policy. The report advocates the establishment of priorities to enhance effective management of the nation's scientific research program in space. It argues that scientific objectives and purposes should determine how and under what circumstances scientific research should be done. The report does not take a position on the controversy between advocates of manned space exploration and those who favor the exclusive use of unmanned space vehicles. Nor does the report address questions about the value or appropriateness of Space Station Freedom or proposals to establish a permanent manned Moon base or to undertake a manned mission to Mars. These issues lie beyond the charge to the task group
Shared decision making in patients with low risk chest pain: prospective randomized pragmatic trial.
OBJECTIVE: To compare the effectiveness of shared decision making with usual care in choice of admission for observation and further cardiac testing or for referral for outpatient evaluation in patients with possible acute coronary syndrome.
DESIGN: Multicenter pragmatic parallel randomized controlled trial.
SETTING: Six emergency departments in the United States.
PARTICIPANTS: 898 adults (aged \u3e17 years) with a primary complaint of chest pain who were being considered for admission to an observation unit for cardiac testing (451 were allocated to the decision aid and 447 to usual care), and 361 emergency clinicians (emergency physicians, nurse practitioners, and physician assistants) caring for patients with chest pain.
INTERVENTIONS: Patients were randomly assigned (1:1) by an electronic, web based system to shared decision making facilitated by a decision aid or to usual care. The primary outcome, selected by patient and caregiver advisers, was patient knowledge of their risk for acute coronary syndrome and options for care; secondary outcomes were involvement in the decision to be admitted, proportion of patients admitted for cardiac testing, and the 30 day rate of major adverse cardiac events.
RESULTS: Compared with the usual care arm, patients in the decision aid arm had greater knowledge of their risk for acute coronary syndrome and options for care (questions correct: decision aid, 4.2 v usual care, 3.6; mean difference 0.66, 95% confidence interval 0.46 to 0.86), were more involved in the decision (observing patient involvement scores: decision aid, 18.3 v usual care, 7.9; 10.3, 9.1 to 11.5), and less frequently decided with their clinician to be admitted for cardiac testing (decision aid, 37% v usual care, 52%; absolute difference 15%; P
CONCLUSIONS: Use of a decision aid in patients at low risk for acute coronary syndrome increased patient knowledge about their risk, increased engagement, and safely decreased the rate of admission to an observation unit for cardiac testing.Trial registration ClinicalTrials.gov NCT01969240
Cancer stem cells: Mediators of tumorigenesis and metastasis in head and neck squamous cell carcinoma
BackgroundCancer stem cells (CSCs) represent a subpopulation of cells responsible for tumor growth. Their role in head and neck squamous cell carcinoma (HNSCC) tumorigenesis and metastasis remains uncertain.MethodsWound healing and an orthotopic animal model were used to study cells expressing the CSC phenotype (CD44high and aldehyde dehydrogenase [ALDH]+) and assess mobility, tumorigenesis, and metastasis. A prospective collection of 40 patientâderived primary HNSCC specimens were analyzed for CSCâproportion compared to clinical variables.ResultsCSCs exhibited significantly faster wound closure and greater tumorigenesis and regional metastasis in vivo than nonâCSCs. In primary patient tumors, size and advanced stage were correlated with elevated proportion of CSCs, however, not with survival.ConclusionHNSCC stem cells mediate tumorigenesis and regional metastasis in vivo. In primary patient tumors, CSCâproportion was associated with tumor size and stage, but not with metastatic spread or survival. CSC burden alone may only represent a minor variable in understanding CSCs and metastasis. © 2014 Wiley Periodicals, Inc. Head Neck 37: 317â326, 2015Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/110728/1/hed23600.pd
Aperiodic MEG abnormality in patients with focal to bilateral tonic-clonic seizures
Aperiodic activity is a physiologically distinct component of the
electrophysiological power spectrum. It is suggested to reflect the balance of
excitation and inhibition in the brain, within selected frequency bands.
However, the impact of recurrent seizures on aperiodic activity remains
unknown, particularly in patients with severe bilateral seizures. Here, we
hypothesised greater aperiodic abnormality in the epileptogenic zone, in
patients with focal to bilateral tonic clonic (FBTC) seizures, and earlier age
of seizure onset.
Pre-operative magnetoencephalography (MEG) recordings were acquired from 36
patients who achieved complete seizure freedom (Engel I outcome) post-surgical
resection. A normative whole brain map of the aperiodic exponent was computed
by averaging across subjects for each region in the hemisphere contralateral to
the side of resection. Selected regions of interest were then tested for
abnormality using deviations from the normative map in terms of z-scores.
Resection masks drawn from postoperative structural imaging were used as an
approximation of the epileptogenic zone.
Patients with FBTC seizures had greater abnormality compared to patients with
focal onset seizures alone in the resection volume (p=0.003, area under the ROC
curve = 0.78 ). Earlier age of seizure onset was correlated with greater
abnormality of the aperiodic exponent in the resection volume (correlation
coefficient = -0.3, p= 0.04)) as well as the whole cortex (rho = -0.33,
p=0.03). The abnormality of the aperiodic exponent did not significantly differ
between the resected and non-resected regions of the brain.
Abnormalities in aperiodic components relate to important clinical
characteristics such as severity and age of seizure onset. This suggests the
potential use of the aperiodic band power component as a marker for severity of
epilepsy
Clustering of magnetic reconnection exhausts in the solar wind: An automated detection study
CONTEXT:
Magnetic reconnection is a fundamental process in astrophysical plasmas that enables the dissipation of magnetic energy at kinetic scales. Detecting this process in situ is therefore key to furthering our understanding of energy conversion in space plasmas. However, reconnection jets typically scale from seconds to minutes in situ, and as such, finding them in the decades of data provided by solar wind missions since the beginning of the space era is an onerous task.
AIMS:
In this work, we present a new approach for automatically identifying reconnection exhausts in situ in the solar wind. We apply the algorithm to Solar Orbiter data obtained while the spacecraft was positioned at between 0.6 and 0.8 AU and perform a statistical study on the jets we detect.
METHODS:
The method for automatic detection is inspired by the visual identification process and strongly relies on the Walén relation. It is enhanced through the use of Bayesian inference and physical considerations to detect reconnection jets with a consistent approach.
RESULTS:
Applying the detection algorithm to one month of Solar Orbiter data near 0.7 AU, we find an occurrence rate of seven jets per day, which is significantly higher than in previous studies performed at 1 AU. We show that they tend to cluster in the solar wind and are less likely to occur in the tenuous solar wind (< 10 cmâ3 near 0.7 AU). We discuss why the source and the degree of AlfvĂ©nicity of the solar wind might have an impact on magnetic reconnection occurrence.
CONCLUSIONS:
By providing a tool to quickly identify potential magnetic reconnection exhausts in situ, we pave the way for broader statistical studies on magnetic reconnection in diverse plasma environments
Modeling root loss reveals impacts on nutrient uptake and crop development
Abstract Despite the widespread prevalence of root loss in plants, its effects on crop productivity are not fully understood. While root loss reduces the capacity of plants to take up water and nutrients from the soil, it may provide benefits by decreasing the resources required to maintain the root system. Here, we simulated a range of root phenotypes in different soils and root loss scenarios for barley (Hordeum vulgare), common bean (Phaseolus vulgaris) and maize (Zea mays) using and extending the open-source, functional-structural root/soil simulation model OpenSimRoot. The model enabled us to quantify the impact of root loss on shoot dry weight in these scenarios and identify in which scenarios root loss is beneficial, detrimental, or has no effect. The simulations showed that root loss is detrimental for phosphorus uptake in all tested scenarios whereas nitrogen uptake was relatively insensitive to root loss unless main root axes were lost. Loss of axial roots reduced shoot dry weight for all phenotypes in all species and soils, whereas lateral root loss had a smaller impact. In barley and maize plants with high lateral branching density that were not phosphorus-stressed, loss of lateral roots increased shoot dry weight. The fact that shoot dry weight increased due to root loss in these scenarios indicates that plants overproduce roots for some environments, such as those found in high-input agriculture. We conclude that a better understanding of the effects of root loss on plant development is an essential part of optimizing root system phenotypes for maximizing yield
An APEX search for carbon emission from NGC 1977 proplyds
We used the Atacama Pathfinder Experiment (APEX) telescope to search for CÂ I 1-0 (492.16Â GHz) emission towards 8 proplyds in NGC 1977, which is an FUV radiation environment two orders of magnitude weaker than that irradiating the Orion Nebular Cluster (ONC) proplyds. CÂ I is expected to enable us to probe the wind launching region of externally photoevaporating discs. Of the 8 targets observed, no 3Ï detections of the CÂ I line were made despite reaching sensitivities deeper than the anticipated requirement for detection from prior APEX CI observations of nearby discs and models of external photoevaporation of quite massive discs. By comparing both the proplyd mass loss rates and CÂ I flux constraints with a large grid of external photoevaporation simulations, we determine that the non-detections are in fact fully consistent with the models if the proplyd discs are very low mass. Deeper observations in CÂ I and probes of the disc mass with other tracers (e.g. in the continuum and CO) can test this. If such a test finds higher masses, this would imply carbon depletion in the outer disc, as has been proposed for other discs with surprisingly low CÂ I fluxes, though more massive discs would also be incompatible with models that can explain the observed mass loss rates and CÂ I non-detections. The expected remaining lifetimes of the proplyds are estimated to be similar to those of proplyds in the ONC at 0.1Â Myr. Rapid destruction of discs is therefore also a feature of common, intermediate UV environments
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