Interference stabilization of autoionizing states in molecular N2N_2 studied by time- and angular-resolved photoelectron spectroscopy

An autoionizing resonance in molecular N$_2$ is excited by an ultrashort XUV pulse and probed by a subsequent weak IR pulse, which ionizes the contributing Rydberg states. Time- and angular-resolved photoelectron spectra recorded with a velocity map imaging spectrometer reveal two electronic contributions with different angular distributions. One of them has an exponential decay rate of $20\pm5$ fs, while the other one is shorter than 10 fs. This observation is interpreted as a manifestation of interference stabilization involving the two overlapping discrete Rydberg states. A formalism of interference stabilization for molecular ionization is developed and applied to describe the autoionizing resonance. The results of calculations reveal, that the effect of the interference stabilization is facilitated by rotationally-induced couplings of electronic states with different symmetry.Comment: 8 pages, 6 figure

Safety of Tiered-Dispatch for 911 Calls for Abdominal Pain

Introduction: Many dispatch systems send Advanced Life Support (ALS) resources to patientscomplaining of abdominal pain even though the majority of these incidents require only Basic LifeSupport (BLS). With increasing 911-call volume, resource utilization has become more important toensure that ALS resources are available for time-critical emergencies. In 2015, a large, urban firedepartment implemented an internally developed, tiered-dispatch system. Under this system, patientsreporting a chief complaint of abdominal pain received the closest BLS ambulance dispatched aloneemergency if located within three miles of the incident. The objective of this study was to determine thesafety of BLS-only dispatch to abdominal pain by determining the frequency of time-sensitive events.Methods: This was a retrospective review of electronic health records of one emergency medicalservice provider agency from May 2015-2018. Inclusion criteria were a chief complaint of abdominalpain from a first- or second-party caller, age over 15, and the patient was reported to be alert andbreathing normally. The primary outcome was the prevalence of time-sensitive events, includingcardiopulmonary resuscitation (CPR), defibrillation, or airway management. Secondary outcomeswere hypotension (systolic blood pressure < 90 mmHg); or a prehospital 12 lead-electrocardiogram(ECG) demonstrating ST-elevation myocardial infarction (STEMI) criteria or a wide complex arrhythmia.Descriptive statistics were used.Results: During the study period, there were 1,220,820 EMS incidents, of which 33,267 (2.72%) metinclusion criteria. The mean age was 49.9 years (range 16-111, standard deviation [SD] 19.6); 14,556patients (56.2%) were female. Time-sensitive events occurred in seven cases (0.021%), mean age was75.3 years (range 30-86, SD18.7); 85.7% were female. Airway management was required in sevencases (0.021%), CPR in six cases (0.018%), and defibrillation in one case (0.003%). Two of the seven(28.6%) cases involved dispatch protocol deviations. Hypotension was present in 240 (0.72%) cases;six (0.018%) cases had 12-lead ECGs meeting STEMI criteria; and no cases demonstrated widecomplex arrhythmia.Conclusion: Among adult 911 patients with a dispatch chief complaint of abdominal pain, time-sensitiveevents were exceedingly rare. Dispatching a BLS ambulance alone appears to be safe

Ultrafast Electronic Band Gap Control in an Excitonic Insulator

We report on the nonequilibrium dynamics of the electronic structure of the layered semiconductor Ta$_2$NiSe$_5$ investigated by time- and angle-resolved photoelectron spectroscopy. We show that below the critical excitation density of $F_{C} = 0.2$ mJ cm$^{-2}$, the band gap $narrows$ transiently, while it is $enhanced$ above $F_{C}$. Hartree-Fock calculations reveal that this effect can be explained by the presence of the low-temperature excitonic insulator phase of Ta$_2$NiSe$_5$, whose order parameter is connected to the gap size. This work demonstrates the ability to manipulate the band gap of Ta$_2$NiSe$_5$ with light on the femtosecond time scale

Subject Retention in Prehospital Stroke Research Using a Telephone-Based Physician-Investigator Driven Enrollment Method.

Background and purposeSubject retention into clinical trials is vital, and prehospital enrollment may be associated with higher rates of subject withdrawal than more traditional methods of enrollment. We describe rates of subject retention in a prehospital trial of acute stroke therapy.MethodsAll subjects were enrolled into the NIH Field Administration of Stroke Therapy-Magnesium (FAST-MAG) phase 3 clinical trial. Paramedics screened eligible subjects and contacted the physician-investigator using a dedicated in-ambulance cellular phone. Physician-investigators obtained explicit informed consent from the subject or on-scene legally authorized representative (LAR) who reviewed and signed a consent form. Exception from informed consent (EFIC) was utilized in later stages of the study.ResultsThere were 1,700 subjects enrolled; 1,017 provided consent (60%), 662 were enrolled via LAR (39%), and 21 were enrolled via EFIC (1%). Of the 1,700 patients, 1,413 (83%) completed the 90-day visit, 265 (16%) died prior to the 90-day visit, and 22 (1.3%) withdrew from the study before completion. There were no differences in rates of withdrawal by method of study enrolment, i.e., self-consent (n = 14), 1.4%; LAR (n = 8), 1.2%; EFIC (n = 0) 0%.ConclusionThere was a high rate of retention when subjects were enrolled into prehospital stroke research using a phone-based method to obtain explicit consent

Causes of prehospital misinterpretations of ST elevation myocardial infarction

Objectives: To determine the causes of software misinterpretation of ST elevation myocardial infarction (STEMI) compared to clinically identified STEMI to identify opportunities to improve prehospital STEMI identification. Methods: We compared ECGs acquired from July 2011 through June 2012 using the LIFEPAK 15 on adult patients transported by the Los Angeles Fire Department. Cases included patients ≥18 years who received a prehospital ECG. Software interpretation of the ECG (STEMI or not) was compared with data in the regional EMS registry to classify the interpretation as true positive (TP), true negative (TN), false positive (FP), or false negative (FN). For cases where classification was not possible using registry data, 3 blinded cardiologists interpreted the ECG. Each discordance was subsequently reviewed to determine the likely cause of misclassification. The cardiologists independently reviewed a sample of these discordant ECGs and the causes of misclassification were updated in an iterative fashion. Results: Of 44,611 cases, 50% were male (median age 65; inter-quartile range 52–80). Cases were classified as 482 (1.1%) TP, 711 (1.6%) FP, 43371 (97.2%) TN, and 47 (0.11%) FN. Of the 711 classified as FP, 126 (18%) were considered appropriate for, though did not undergo, emergent coronary angiography, because the ECG showed definite (52 cases) or borderline (65 cases) ischemic ST elevation, a STEMI equivalent (5 cases) or ST-elevation due to vasospasm (4 cases). The sensitivity was 92.8% [95% CI 90.6, 94.7%] and the specificity 98.7% [95% CI 98.6, 98.8%]. The leading causes of FP were ECG artifact (20%), early repolarization (16%), probable pericarditis/myocarditis (13%), indeterminate (12%), left ventricular hypertrophy (8%), and right bundle branch block (5%). There were 18 additional reasons for FP interpretation (<4% each). The leading causes of FN were borderline ST-segment elevations less than the algorithm threshold (40%) and tall T waves reducing the ST/T ratio below threshold (15%). There were 11 additional reasons for FN interpretation occurring ≤3 times each. Conclusion: The leading causes of FP automated interpretation of STEMI were ECG artifact and non-ischemic causes of ST-segment elevation. FN were rare and were related to ST-segment elevation or ST/T ratio that did not meet the software algorithm threshold

Domain generalization across tumor types, laboratories, and species — Insights from the 2022 edition of the Mitosis Domain Generalization Challenge

Recognition of mitotic figures in histologic tumor specimens is highly relevant to patient outcome assessment. This task is challenging for algorithms and human experts alike, with deterioration of algorithmic performance under shifts in image representations. Considerable covariate shifts occur when assessment is performed on different tumor types, images are acquired using different digitization devices, or specimens are produced in different laboratories. This observation motivated the inception of the 2022 challenge on MItosis Domain Generalization (MIDOG 2022). The challenge provided annotated histologic tumor images from six different domains and evaluated the algorithmic approaches for mitotic figure detection provided by nine challenge participants on ten independent domains. Ground truth for mitotic figure detection was established in two ways: a three-expert majority vote and an independent, immunohistochemistry-assisted set of labels. This work represents an overview of the challenge tasks, the algorithmic strategies employed by the participants, and potential factors contributing to their success. With an score of 0.764 for the top-performing team, we summarize that domain generalization across various tumor domains is possible with today’s deep learning-based recognition pipelines. However, we also found that domain characteristics not present in the training set (feline as new species, spindle cell shape as new morphology and a new scanner) led to small but significant decreases in performance. When assessed against the immunohistochemistry-assisted reference standard, all methods resulted in reduced recall scores, with only minor changes in the order of participants in the ranking

Direct Imaging of Transient Fano Resonances in N2 Using Time-, Energy-, and Angular-Resolved Photoelectron Spectroscopy

Autoionizing Rydberg states of molecular N2 are studied using time-, energy-, and angular-resolved photoelectron spectroscopy. A femtosecond extreme ultraviolet pulse with a photon energy of 17.5 eV excites the resonance and a subsequent IR pulse ionizes the molecule before the autoionization takes place. The angular-resolved photoelectron spectra depend on pump-probe time delay and allow for the distinguishing of two electronic states contributing to the resonance. The lifetime of one of the contributions is determined to be 14±1 fs, while the lifetime of the other appears to be significantly shorter than the time resolution of the experiment. These observations suggest that the Rydberg states in this energy region are influenced by the effect of interference stabilization and merge into a complex resonance

Marked Circadian Variation in Number and Type of Hyperacute Strokes During the 24 Hour Day-Night Cycle

Introduction: Circadian variations in stroke onset provide critical information for the allocation of pre-hospital and hospital resources in clinical care. Confining analysis to patients with defined onset in waking and clearly distinguished ischemic and hemorrhagic stroke subtypes, would substantial benefit our understanding of stroke etiology. Methods: We analyzed patients enrolled in the NIH FAST-MAG phase 3 trial of field-initiated neuroprotective agents in patients with hyperacute stroke within 2h of onset. Onset times were analyzed in 1h time blocks throughout the 24h day-night cycle. Patient demographic and clinical features, medical history, imaging characteristics, and stroke deficit severity were correlated with onset times. Results: Among 1632 patients, final diagnoses were acute cerebral ischemia in 76.2% and intracranial hemorrhage in 23.7%. Acute cerebral ischemia (ACI) had a unimodal distribution with peak onset at midday (12:00-12:59); intracerebral hemorrhage (ICH) a bimodal distribution with peaks at mid-morning (08:00-08:59) and early evening (18:00-18:59). Events were markedly reduced in early morning, with only 3.4% starting in the first 25% of the day. The proportion of hemorrhagic was higher in the first 8h of the day (00:00-07:59) than the remaining 16h, 33.3% vs 22.5%, p=0.006. ACI and ICH patients displayed fairly homogeneous vascular risk factors, presenting deficit severity, and initial brain imaging findings across all time periods. Discussion: There is marked, more than 10-fold, circadian variation in onset of acute cerebrovascular disease, and circadian variation in the ratio of ischemic to hemorrhagic neurovascular events. These findings can inform resource planning for regional systems of acute stroke care