Radial evolution of sunward strahl electrons in the inner heliosphere

The heliospheric magnetic field (HMF) exhibits local inversions, in which the field apparently “bends back” upon itself. Candidate mechanisms to produce these inversions include various configurations of upstream interchange reconnection; either in the heliosphere, or in the corona where the solar wind is formed. Explaining the source of these inversions, and how they evolve in time and space, is thus an important step towards explaining the origins of the solar wind. Inverted heliospheric magnetic field lines can be identified by the anomalous sunward (i.e. inward) streaming of the typically anti-sunward propagating, field aligned (or anti-aligned), beam of electrons known as the “strahl”. We test if the pitch angle distribution (PAD) properties of sunward-propagating strahl are different from those of outward strahl.We perform a statistical study of strahl observed by the Helios spacecraft, over heliocentric distances spanning ≈ 0.3 – 1 AU. We find that sunward strahl PADs are broader and less intense than their outward directed counterparts; particularly at distances 0.3 – 0.75 AU. This is consistent with sunward strahl being subject to additional, path-length dependent, scattering in comparison to outward strahl.We conclude that the longer and more variable path from the Sun to the spacecraft, along inverted magnetic field, leads to this additional scattering. The results also suggest that the relative importance of scattering along this additional path length drops off with heliocentric distance. These results can be explained by a relatively simple, constant-rate, scattering process

National Football League Skilled and Unskilled Positions Vary in Opportunity and Yield in Return to Play After an Anterior Cruciate Ligament Injury.

BACKGROUND: Anterior cruciate ligament (ACL) injuries pose a significant risk to the careers of players in the National Football League (NFL). The relationships between draft round and position on return to play (RTP) among NFL players are not well understood, and the ability to return to preinjury performance levels remains unknown for most positions. PURPOSE: To test for differences in RTP rates and changes in performance after an ACL injury by position and draft round. We hypothesized that skilled positions would return at a lower rate compared to unskilled positions. We further hypothesized that early draft-round status would relate to a greater rate of RTP and that skilled positions and a lower draft round would correlate with decreased performance for players who return to sport. STUDY DESIGN: Case-control study; Level of evidence, 3. METHODS: Utilizing a previously established database of publicly available information regarding ACL tears among NFL players, athletes with ACL tears occurring between the 2010 and 2013 seasons were identified. Generalized linear models and Kaplan-Meier time-to-event models were used to test the study hypotheses. RESULTS: The overall RTP rate was 61.7%, with skilled players and unskilled players returning at rates of 64.1% and 60.4%, respectively (P = .74). Early draft-round players and unskilled late draft-round players had greater rates of RTP compared to skilled late draft-round players and both unskilled and skilled undrafted free agents (UDFAs). Skilled early draft-round players constituted the only cohort that played significantly fewer games after an injury. Unskilled UDFAs constituted the only cohort to show a significant increase in the number of games started and ratio of games started to games played, starting more games in which they played, after an injury. CONCLUSION: Early draft-round and unskilled players were more likely to return compared to their later draft-round and skilled peers. Skilled early draft-round players, who displayed relatively high rates of RTP, constituted the only cohort to show a decline in performance. Unskilled UDFAs, who exhibited relatively low rates of RTP, constituted the only cohort to show an increase in performance. The significant effect of draft round and position type on RTP may be caused by a combination of differences in talent levels and in opportunities given to returning to play

Problem-Solving Stereotypes for an Intelligent Assistant

This paper examines the role of case-based reasoning in a problem-solving assistant system, which differs from an autonomous problem solver in that it shares the problem-solving task with a human partner. The paper focuses on the criteria driving the system designer's (or the system's) choice of cases, of representation vocabulary, and of indexing terms, and upon how the assumption of a human in the problem-solving loop influences these criteria. It presents these theoretical considerations in the context of work in progress on lOPS, a case-based intelligent assistant for airline irregular operations scheduling

Contact as catalyst: The case for Coptic influence in the development of Arabic negation

This article discusses similar developments in the expression of negation in the histories of Egyptian-Coptic and Arabic and explores the evidence for these respective developments being related by language contact. Both Coptic and Arabic have undergone a development known as Jespersen’s Cycle (JC), whereby an original negative marker is joined by some new element to form a bipartite negative construction. The original marker then becomes optional while the new element becomes the primary negator. We present the results of a corpus study of negation in late Coptic, showing that, at the time when Arabic speakers began to settle in Egypt, the bipartite negative construction still predominated. This being the case, we argue that native speakers of Coptic learning Arabic as a second language played a key role in the genesis of the Arabic bipartite negative construction. More generally, we give reasons to doubt the a priori preference for internal explanations of syntactic change over those involving contact, as well as the assumption that the two are mutually exclusive. Rather, we suggest that not only purely internal but also (partially) contactinduced change can profitably be accounted for in terms of child language acquisition leading to a change in the grammars of individual speakers

Testing the current paradigm for space weather prediction with heliospheric imagers

Predictions of the arrival of four coronal mass ejections (CMEs) in geospace are produced through use of three CME geometric models combined with CME drag modeling, constraining these models with the available Coronagraph and Heliospheric Imager data. The efficacy of these predications is assessed by comparison with the Space Weather Prediction Center (SWPC) numerical MHD forecasts of these same events. It is found that such a prediction technique cannot outperform the standard SWPC forecast at a statistically meaningful level. We test the Harmonic Mean, Self-Similar Expansion, and Ellipse Evolution geometric models, and find that, for these events at least, the differences between the models are smaller than the observational errors. We present a new method of characterizing CME fronts in the Heliospheric Imager field of view, utilizing the analysis of citizen scientists working with the Solar Stormwatch project, and we demonstrate that this provides a more accurate representation of the CME front than is obtained by experts analyzing elongation time maps for the studied events. Comparison of the CME kinematics estimated independently from the STEREO-A and STEREO-B Heliospheric Imager data reveals inconsistencies that cannot be explained within the observational errors and model assumptions. We argue that these observations imply that the assumptions of the CME geometric models are routinely invalidated and question their utility in a space weather forecasting context. These results argue for the continuing development of more advanced techniques to better exploit the Heliospheric Imager observations for space weather forecasting

Cues and knowledge structures used by mental-health professionals when making risk assessments

Background: Research into mental-health risks has tended to focus on epidemiological approaches and to consider pieces of evidence in isolation. Less is known about the particular factors and their patterns of occurrence that influence clinicians’ risk judgements in practice. Aims: To identify the cues used by clinicians to make risk judgements and to explore how these combine within clinicians’ psychological representations of suicide, self-harm, self-neglect, and harm to others. Method: Content analysis was applied to semi-structured interviews conducted with 46 practitioners from various mental-health disciplines, using mind maps to represent the hierarchical relationships of data and concepts. Results: Strong consensus between experts meant their knowledge could be integrated into a single hierarchical structure for each risk. This revealed contrasting emphases between data and concepts underpinning risks, including: reflection and forethought for suicide; motivation for self-harm; situation and context for harm to others; and current presentation for self-neglect. Conclusions: Analysis of experts’ risk-assessment knowledge identified influential cues and their relationships to risks. It can inform development of valid risk-screening decision support systems that combine actuarial evidence with clinical expertise

THE ROLE OF THE ARCHITECT IN THE PROCESS OF DEVELOPMENT

Population growth and cars have caused cities to sprawl from their downtown cores, resulting in a landscape of low density building. Far too often the empty lot at the edge of the city or along a highway attracts the next opportunity for development, furthering the gap between residential and commercial zones. The profession of architecture recognizes that urban site selection and mixed-use programming is vital to the social and financial health of a city, though it typically only participates in the design of the building. However, the visionary training and practice of architecture places the architect in a unique position to initiate successful projects on sites that are undervalued. That reality suggests that the architect’s role in the process of development should be expanded in order to participate in programming and site selection. This expanded role will lead to more frequent and better quality urban development which is supported by financial incentives for cities, developers, and architects

Examining the Intersection of Refugee Policies and Contemporary Protracted Displacement

Article 33 of the 1951 Convention Relating to the Status of Refugees states that host nations shall not expel or return a refugee to their home nation ‘where his life or freedom would be threatened.’ However, as demonstrated in three contemporary case studies in protracted displacement the interests of the sovereign state drive nations to craft strategies to limit cross-border refugee mobility. The refoulement of refugees escaping drug cartel violence throughout the Americas, internally displaced Haitians, and Syrian refugees in Jordan are all ‘managed’ by one of two methods. First, some destination nations either strategically blur refugees into other mobility schemes such economic migrants, illegal immigrants, link refugees to terrorist groups or nations outright replace the term refugee with words like guest. The benefit of this nomenclature strategy avoids refugee ‘laws’ altogether. The second strategy outright prevents the need to refoule by regulating or outright stopping refugee border crossings altogether. The border control strategy allows for refugee considerations, however prevents the host nation from engaging in Article 33 violations. Regardless of the strategy, host nations create policies that prioritize the protection and sovereignty of the host nations over the needs of individual refugees and the growing number of refugees in protracted displacement situations