Search

We conducted a search for technosignatures in 2018 and 2019 April with the L-band receiver (1.15-1.73 GHz) of the 100 m diameter Green Bank Telescope. These observations focused on regions surrounding 31 Sun-like stars near the plane of the Galaxy. We present the results of our search for narrowband signals in this data set, as well as improvements to our data processing pipeline. Specifically, we applied an improved candidate signal detection procedure that relies on the topographic prominence of the signal power, which nearly doubles the signal detection count of some previously analyzed data sets. We also improved the direction-of-origin filters that remove most radio frequency interference (RFI) to ensure that they uniquely link signals observed in separate scans. We performed a preliminary signal injection and recovery analysis to test the performance of our pipeline. We found that our pipeline recovers 93% of the injected signals over the usable frequency range of the receiver and 98% if we exclude regions with dense RFI. In this analysis, 99.73% of the recovered signals were correctly classified as technosignature candidates. Our improved data processing pipeline classified over 99.84% of the ∼26 million signals detected in our data as RFI. Of the remaining candidates, 4539 were detected outside of known RFI frequency regions. The remaining candidates were visually inspected and verified to be of anthropogenic nature. Our search compares favorably to other recent searches in terms of end-to-end sensitivity, frequency drift rate coverage, and signal detection count per unit bandwidth per unit integration time.

We report the first detections of the repeating fast radio burst source FRB 121102 above 5.2 GHz. Observations were performed using the 4-8 GHz receiver of the Robert C. Byrd Green Bank Telescope with the Breakthrough Listen digital backend. We present the spectral, temporal, and polarization properties of 21 bursts detected within the first 60 minutes of a total of 6 hr of observations. These observations comprise the highest burst density yet reported in the literature, with 18 bursts being detected in the first 30 minutes. A few bursts clearly show temporal sub-structure with distinct spectral properties. These sub-structures superimpose to provide an enhanced peak signal-to-noise ratio at higher trial dispersion measures. Broad features occur in ∼1 GHz wide subbands that typically differ in peak frequency between bursts within the band. Finer-scale structures (∼10-50 MHz) within these bursts are consistent with the structure expected from Galactic diffractive interstellar scintillation. The bursts exhibit nearly 100% linear polarization, and a large average rotation measure of 9.359 ± 0.012 ×104 rad m-2 (in the observer's frame). No circular polarization was found for any burst. We measure an approximately constant polarization position angle in the 13 brightest bursts. The peak flux densities of the reported bursts have average values (0.2 ± 0.1 Jy) similar to those seen at lower frequencies (

We analyse the stochastic properties of the 49 pulsars that comprise the first International Pulsar Timing Array (IPTA) data release. We use Bayesian methodology, performing model selection to determine the optimal description of the stochastic signals present in each pulsar. In addition to spin-noise and dispersion-measure (DM) variations, these models can include timing noise unique to a single observing system, or frequency band. We show the improved radio-frequency coverage and presence of overlapping data from different observing systems in the IPTA data set enables us to separate both system and band-dependent effects with much greater efficacy than in the individual pulsar timing array (PTA) data sets. For example, we show that PSR J1643-1224 has, in addition to DM variations, significant band-dependent noise that is coherent between PTAs which we interpret as coming from time-variable scattering or refraction in the ionized interstellar medium. Failing to model these different contributions appropriately can dramatically alter the astrophysical interpretation of the stochastic signals observed in the residuals. In some cases, the spectral exponent of the spin-noise signal can vary from 1.6 to 4 depending upon the model, which has direct implications for the long-term sensitivity of the pulsar to a stochastic gravitational-wave (GW) background. By using a more appropriate model, however, we can greatly improve a pulsar's sensitivity to GWs. For example, including system and band-dependent signals in the PSR J0437-4715 data set improves the upper limit on a fiducial GW background by ~60 per cent compared to a model that includes DM variations and spin-noise only.

That African American communities are too often desolate places where it seems, in Hurston's words, 'life has been and gone,' argues for increasingly creative community development strategies. This paper presents an historically-based, corporate empowerment model designed to address the desolation, by re-uniting scholars, practitioners and other community stakeholders for collective benefit and empowerment. Through an African-centered evaluative discussion, the authors assume the professional risk of sharing an outcome that may be viewed as a failure. The efficacy of the model, juxtaposed against the continued powerlessness of African American scholars, practitioners and communities, is explored. Practice challenges and implications are discussed. [ABSTRACT FROM AUTHOR]

Fast radio bursts (FRBs) are brief, intense flashes of radio waves from unidentified extragalactic sources. Polarized FRBs originate in highly magnetized environments. We report observations of the repeating FRB 20190520B spanning 17 months, which show that the FRB's Faraday rotation is highly variable and twice changes sign. The FRB also depolarizes below radio frequencies of about 1 to 3 gigahertz. We interpret these properties as being due to changes in the parallel component of the magnetic field integrated along the line of sight, including reversing direction of the field. This could result from propagation through a turbulent magnetized screen of plasma, located 10 -5 to [Formula: see text] parsecs from the FRB source. This is consistent with the bursts passing through the stellar wind of a binary companion of the FRB source.

The polarization of fast radio bursts (FRBs), which are bright astronomical transient phenomena, contains information about their environments. Using wide-band observations with two telescopes, we report polarization measurements of five repeating FRBs and find a trend of lower polarization at lower frequencies. This behavior is modeled as multipath scattering, characterized by a single parameter, σ RM , the rotation measure (RM) scatter. Sources with higher σ RM have higher RM magnitude and scattering time scales. The two sources with the highest σ RM , FRB 20121102A and FRB 20190520B, are associated with compact persistent radio sources. These properties indicate a complex environment near the repeating FRBs, such as a supernova remnant or a pulsar wind nebula, consistent with their having arisen from young stellar populations.

We search for a first-order phase transition gravitational wave signal in 45 pulsars from the NANOGrav 12.5-year dataset. We find that the data can be modeled in terms of a strong first order phase transition taking place at temperatures below the electroweak scale. However, we do not observe any strong preference for a phase-transition interpretation of the signal over the standard astrophysical interpretation in terms of supermassive black hole mergers; but we expect to gain additional discriminating power with future datasets, improving the signal to noise ratio and extending the sensitivity window to lower frequencies. An interesting open question is how well gravitational wave observatories could separate such signals.

Einstein's theory of gravity-the general theory of relativity 1 -is based on the universality of free fall, which specifies that all objects accelerate identically in an external gravitational field. In contrast to almost all alternative theories of gravity 2 , the strong equivalence principle of general relativity requires universality of free fall to apply even to bodies with strong self-gravity. Direct tests of this principle using Solar System bodies 3,4 are limited by the weak self-gravity of the bodies, and tests using pulsar-white-dwarf binaries 5,6 have been limited by the weak gravitational pull of the Milky Way. PSR J0337+1715 is a hierarchical system of three stars (a stellar triple system) in which a binary consisting of a millisecond radio pulsar and a white dwarf in a 1.6-day orbit is itself in a 327-day orbit with another white dwarf. This system permits a test that compares how the gravitational pull of the outer white dwarf affects the pulsar, which has strong self-gravity, and the inner white dwarf. Here we report that the accelerations of the pulsar and its nearby white-dwarf companion differ fractionally by no more than 2.6 × 10 -6 . For a rough comparison, our limit on the strong-field Nordtvedt parameter, which measures violation of the universality of free fall, is a factor of ten smaller than that obtained from (weak-field) Solar System tests 3,4 and a factor of almost a thousand smaller than that obtained from other strong-field tests 5,6 .

Fast radio bursts are millisecond-duration, extragalactic radio flashes of unknown physical origin. The only known repeating fast radio burst source-FRB 121102-has been localized to a star-forming region in a dwarf galaxy at redshift 0.193 and is spatially coincident with a compact, persistent radio source. The origin of the bursts, the nature of the persistent source and the properties of the local environment are still unclear. Here we report observations of FRB 121102 that show almost 100 per cent linearly polarized emission at a very high and variable Faraday rotation measure in the source frame (varying from +1.46 × 10 5 radians per square metre to +1.33 × 10 5 radians per square metre at epochs separated by seven months) and narrow (below 30 microseconds) temporal structure. The large and variable rotation measure demonstrates that FRB 121102 is in an extreme and dynamic magneto-ionic environment, and the short durations of the bursts suggest a neutron star origin. Such large rotation measures have hitherto been observed only in the vicinities of massive black holes (larger than about 10,000 solar masses). Indeed, the properties of the persistent radio source are compatible with those of a low-luminosity, accreting massive black hole. The bursts may therefore come from a neutron star in such an environment or could be explained by other models, such as a highly magnetized wind nebula or supernova remnant surrounding a young neutron star.

Gravitationally bound three-body systems have been studied for hundreds of years and are common in our Galaxy. They show complex orbital interactions, which can constrain the compositions, masses and interior structures of the bodies and test theories of gravity, if sufficiently precise measurements are available. A triple system containing a radio pulsar could provide such measurements, but the only previously known such system, PSR B1620-26 (refs 7, 8; with a millisecond pulsar, a white dwarf, and a planetary-mass object in an orbit of several decades), shows only weak interactions. Here we report precision timing and multiwavelength observations of PSR J0337+1715, a millisecond pulsar in a hierarchical triple system with two other stars. Strong gravitational interactions are apparent and provide the masses of the pulsar M[Symbol: see text](1.4378(13), where M[Symbol: see text]is the solar mass and the parentheses contain the uncertainty in the final decimal places) and the two white dwarf companions (0.19751(15)M[Symbol: see text] and 0.4101(3))M[Symbol: see text], as well as the inclinations of the orbits (both about 39.2°). The unexpectedly coplanar and nearly circular orbits indicate a complex and exotic evolutionary past that differs from those of known stellar systems. The gravitational field of the outer white dwarf strongly accelerates the inner binary containing the neutron star, and the system will thus provide an ideal laboratory in which to test the strong equivalence principle of general relativity.

Many physically motivated extensions to general relativity (GR) predict substantial deviations in the properties of spacetime surrounding massive neutron stars. We report the measurement of a 2.01 ± 0.04 solar mass (M⊙) pulsar in a 2.46-hour orbit with a 0.172 ± 0.003 M⊙ white dwarf. The high pulsar mass and the compact orbit make this system a sensitive laboratory of a previously untested strong-field gravity regime. Thus far, the observed orbital decay agrees with GR, supporting its validity even for the extreme conditions present in the system. The resulting constraints on deviations support the use of GR-based templates for ground-based gravitational wave detectors. Additionally, the system strengthens recent constraints on the properties of dense matter and provides insight to binary stellar astrophysics and pulsar recycling.

Today's clinical nursing education challenges center around managing complex issues related to clinical placements. The increased numbers and varying levels of nursing students, acuity and intensity of the clinical setting, and rise of regulatory and accrediting mandates provided impetus for the establishment of the Alliance for Clinical Education (ACE). This article describes community standards established by partnering educational programs and clinical agencies in the Denver, Colorado, and surrounding areas. ACE is successfully confronting the challenges of effectively using scarce clinical placements, validating student orientation mandates, and facilitating the availability and development of qualified clinical faculty. Examples of tools and resources created by ACE to provide uniformity in meeting mutual expectations and requirements are described. The power of collaboration and sharing expertise is described by current initiatives, which reflect the ability to influence policy and shape community standards to support excellence in clinical nursing education.

Tested hypotheses from state-trait theory applied to anger while driving. College student drivers high in trait driving anger were compared to drivers low in trait driving anger. High anger drivers were more frequently angered in day-to-day driving (frequency hypothesis). They reported more intense anger in their most angering driving situations, when visualizing provocative driving events, and in day-to-day driving (intensity hypothesis). Driving diaries and surveys showed they engaged in more aggressive behavior and expressed their anger through more verbal, physical, and vehicular means (aggression hypothesis). They reported handling of their anger less well when visualizing provocative events and on the Adaptive/Constructive Expression scale (reduced adaptive expression hypothesis). They engaged in risky behavior (risky behavior hypothesis) and experienced more moving violations, close calls, and losses of concentration, but not more major or minor accidents (partial support for crash-related outcomes hypothesis). High anger drivers were more generally angry and impulsive and employed more negative, less controlled forms of general anger expression. Results supported state-trait theory and added to the literature showing that high anger drivers have some other psychological and behavioral characteristics that may interact negatively with anger behind the wheel.

This research tested hypotheses from state-trait anger theory applied to anger while driving. High and low anger drivers drove equally often and as many miles, but high anger drivers reported more frequent and intense anger and more aggression and risky behavior in daily driving, greater anger in frequently occurring situations, more frequent close calls and moving violations, and greater use of hostile/aggressive and less adaptive/constructive ways of expressing anger. In low impedance simulations, groups did not differ on state anger or aggression; however, high anger drivers reported greater state anger and verbal and physical aggression in high impedance simulations. High anger drivers drove at higher speeds in low impedance simulations and had shorter times and distances to collision and were twice as likely to crash in high impedance simulations. Additionally, high anger drivers were more generally angry. Hypotheses were generally supported, and few gender differences were noted for anger and aggression.

High anger drivers who acknowledged problems with driving anger and were interested in treatment were compared to high and low anger drivers who did not acknowledge problems with driving anger or want treatment. Although high anger drivers who acknowledged problems reported greater anger on two measures than high anger drivers who did not acknowledge problems, both high anger groups tended not to differ from one another and were more frequently and intensely angered when driving, reported more aggressive and less adaptive/constructive forms of expressing anger while driving, engaged in more aggressive and risky behavior on the road, and experienced more of some accident-related outcomes than low anger drivers. High anger groups did not differ from each other, but reported more trait anxiety and anger and more outward negative and less controlled general anger expression than the low anger group. The two groups of high anger drivers, however, require different types of interventions given their state of readiness for driving anger reduction. Results were also interpreted as supportive of the state-trait model of anger and construct validity of the Driving Anger Scale.

Relaxation and cognitive-relaxation interventions were compared to a no treatment control in the treatment of high anger drivers. The cognitive portion of the cognitive-relaxation condition adapted the style of Beck's cognitive therapy, particularly use of Socratic questions and behavioral experiments and tryouts, to driving anger reduction. Both interventions lowered indices of driving anger and hostile and aggressive forms of expressing driving anger and increased adaptive/constructive ways of expressing driving anger. The cognitive-relaxation intervention also lowered the frequency of risky behavior. Both interventions lowered trait anger as well. Limitations and implications for treatment and research were discussed.

Four ways people express their anger when driving were identified. Verbal Aggressive Expression (alpha=0.88) assesses verbally aggressive expression of anger (e.g., yelling or cursing at another driver); Personal Physical Aggressive Expression (alpha=0.81), the ways the person uses him/herself to express anger (e.g., trying to get out and tell off or have a physical fight with another driver); Use of the Vehicle to Express Anger (alpha=0.86), the ways the person uses his/her vehicle to express anger (e.g., flashing lights at or cutting another driver off in anger); and Adaptive/Constructive Expression (alpha=0.90), the ways the person copes positively with anger (e.g., focuses on safe driving or tries to relax). Aggressive forms can be summed into Total Aggressive Expression Index (alpha=0.90). Aggressive forms of expression correlated positively with each other (rs=0.39-0.48), but were uncorrelated or correlated negatively with adaptive/constructive expression (rs=-0.02 to -0.22). Aggressive forms of anger expression correlated positively with driving-related anger, aggression, and risky behavior; adaptive/constructive expression tended to correlate negatively with these variables. Differences in the strengths of correlations and regression analyses supported discriminant and incremental validity and suggested forms of anger expression contributed differentially to understanding driving-related behaviors. Theoretical and treatment implications were explored.

This study provided evidence of reliability and validity for the four scales of the Driving Anger Expression Inventory. Alpha reliabilities for scales ranged from .84 to .89. Measures of aggressive anger expression while driving (Verbal Aggressive Expression, Personal Physical Aggressive Expression, and Use of the Vehicle to Express Anger scales) correlated positively with each other and negatively with the Adaptive/Constructive Expression scale. Scores on the three aggressive forms of anger expression correlated positively with trait anger and measures of driving-related anger, aggression, and risky behavior, whereas scores on the Adaptive/Constructive Expression scale correlated negatively with these variables. Reports of aggressive and risky behavior correlated most strongly with the Use of the Vehicle to Express Anger scale. Forms of anger expression were minimally or uncorrelated with rated trait anxiety and reports of moving violations, close calls, and accidents. Findings replicated earlier findings and provided further evidence for the reliability and validity of the Driving Anger Expression Inventory.

Cluster analysis, using TRYSYS key cluster variable analyses, on 59 anger expression items replicated Spielberger's Anger-In and Anger-Control dimensions and revealed seven additional forms of anger expression: Noisy Arguing, Verbal Assault, Physical Assault-People, Physical Assault-Objects, Reciprocal Communication, Time Out, and Direct Expression. Aggressive dimensions (Noisy Arguing, Verbal Assault, Physical Assault-People and -Objects) correlated positively with each other and with trait anger and negatively with non-aggressive forms of expression (Control, Reciprocal Communication, and Time Out). The latter were positively correlated with each other and negatively with trait anger. Forms of expression correlated logically with the frequency of eight types of anger consequences, and there was evidence of distinct relationships between anger expression and anger consequences; e.g. Physical Assault-People correlated most with frequency of physical altercations, and Noisy Arguing and Verbal Assault with the frequency of verbal fights. Males were more likely to utilize aggressive forms of expression and to suffer consequences involving physical and verbal fights and property damage. Results are discussed in terms of convergent and discriminant validity, and in terms of their implications for assessment, treatment, and future research.

A cluster analysis of responses from more than 1500 college students to 53 potentially angering driving-related situations yielded a 33-item driving anger scale (alpha reliability = .90) with six reliable subscales involving hostile gestures, illegal driving, police presence, slow driving, discourtesy, and traffic obstructions. Subscales all correlated positively, suggesting a general dimension of driving anger as well as anger related to specific driving-related situations. Men were more angered by police presence and slow driving whereas women were more angered by illegal behavior and traffic obstructions, but differences compensated so there were no gender differences on total score. A 14-item short form (alpha reliability = .80) was developed from scores more highly correlated (r = .95) with scores on the long form. Driving anger may have potential value for research on accident prevention and health psychology.

The present study was designed to examine relationships between the life values of 399 U.S. college students and their nuclear war-related thoughts, feelings, and behaviors. The students completed four scales from the Life Values Inventory: (i.e. Conventionally Defined Success [CDS]; Religious Faith and Devotion [RFD]; Activist Pursuit of Social Causes [APSC]; Materialistic Orientation [MO]), the Satisfaction With Life Scale, four scales from the Nuclear War Inventory--Nuclear Distress; Salience; Weapons Opposition; Personal Efficacy--and a single behavioral measure of approach toward information concerning nuclear weapons. Consistent with theory regarding the influence of values and commitments on attitudes and behavior, APSC was found to be positively associated with all five nuclear war measures. Additionally, MO was negatively related to Personal Efficacy and Information Approach, and CDS was positively associated with Nuclear Distress. The only value dimension which covaried significantly with general life satisfaction was RFD. Results are discussed with respect to the recent rise in conservative and materialistically-oriented values among American college students.