Chief Finding Research Articles

Calibration of Ray-Tracing With Diffuse Scattering Against 28-GHz Directional Urban Channel Measurements

This paper describes the calibration of the Volcano ray-tracing engine against channel measurements collected in an urban environment with a state-of-the-art 28-GHz directional channel sounder. A discrete set of rays, representing planar wavefronts propagating between the transmitter and receiver, were extracted from the measurements and characterized in path gain, delay, and 3D angle-of-arrival through super-resolution techniques, with average errors of only 1.2 dB, 0.55 ns, and 2.05° respectively. The extracted rays were then tracked over space as the receiver, mounted on a mobile rover equipped with military-grade GPS, traversed 66 m while amassing a total of 488 channel acquisitions. The tracked rays were then mapped to rays predicted from ray-tracing, originating through specular reflection or diffuse scattering from ambient objects. The mapping enabled object-specific calibration, namely calibrating distinct diffuse-scattering models for buildings, vehicles, and foliage. To our knowledge, this is the first effort to calibrate ray-tracing with object-specific diffuse scattering models against rays individually mapped in the path gain, delay, angle, and space domains. Results, in terms of calibrated ray-tracing parameters, fit-error statistics, and lessons learned, are included. Our chief finding was that, while most papers on millimeter-wave ray-tracing do not even consider diffuse scattering, it accounted for 20% of the total received power, whereas diffraction accounted for less than 1%.

Exploring a framework for the mentoring of early career teachers in Catholic schools in Western Australia

The basis for the paper ‘Exploring a Framework for the Mentoring of Early Career Teachers in Catholic Schools in Western Australia’ stems from the work undertaken in the author’s recently published PhD study (Topliss 2017) and on personal experiences of teaching philosophy to students as a classroom teacher, gifted and talented coordinator and School leader for over 28 years. The mixed methods study identified and explored the mentoring experiences in the transition from graduate to Early Career Teacher (ECT) in selected Catholic primary and secondary schools in Western Australia. The research addressed a significant deficit, as presently the lack of a system-wide framework for the mentoring of ECTs, the cessation of the current ECT program and the limited training of mentors, has resulted in less than ideal mentoring experiences for ECTs. A chief finding was that the guarantee of a mentor does not necessarily alleviate every problem faced by an ECT. However, the attributes of a mentor may significantly assist or hinder the aspirations of an ECT. Encouragingly, the majority of principals recognised the importance of mentoring by offering support for the instigation of a system-wide mentoring framework. On the basis of these findings, principles upon which a new mentoring framework might be developed are proposed. The suggested system frame-work for Western Australian Catholic Education, titled ‘Borromeo’s Mentoring Framework’, may benefit system-leaders, principals, mentors and ECTs through the implementation of programs at a school based level, that enhance critical thinking skills i.e. Philosophy for Children (P4C) and Circle of Inquiry (CoI).

“I never needed eyes to see”: Leveraging extreme challenges for successful venture creation

Challenge-based entrepreneurship is a nascent research area that has sought to tackle a longstanding issue of how entrepreneurs may overcome extreme challenges. We seek fresh insights into this issue by researching entrepreneurs who face one of the most extreme physical challenges, namely of acute sight loss (“blindness”). While this condition carries social perceptions of extreme physical incapacity and performance limitations, there continue to be notable examples of entrepreneurs with permanent blindness. How do blind entrepreneurs overcome barriers resulting from their impairment? By observing and conversing with two blind serial entrepreneurs, we offer preliminary answers to this question by generating insights into processes of opportunity formation in which ideas are conceived and developed out of the entrepreneurs' challenges. Our chief finding is that our blind entrepreneurs instrumentalized their impairments for commercial or social purposes by creating ventures that leveraged public perceptions of blindness and disability. Accordingly, in their ventures, our entrepreneurs drew on distinctive attributes of their physical and social challenges as a means of exploiting narrow conceptions of disabled people's capabilities. These entrepreneurs therefore overcame their challenges by capitalizing on public conceptions of their limited capabilities. The subsequent Discussion offers research opportunities in and beyond challenge-based entrepreneurship by considering a number of theoretical and practical implications of the adaptive skills and attributes of our entrepreneurs that have enabled them to engage with popular “ableist” and medical, or “tragic”, perceptions of disability in original and positive ways.

On the convergence of spectral deferred correction methods

In this work we analyze the convergence properties of the Spectral Deferred Correction (SDC) method originally proposed by Dutt et al. [BIT, 40 (2000), pp. 241--266]. The framework for this high-order ordinary differential equation (ODE) solver is typically described wherein a low-order approximation (such as forward or backward Euler) is lifted to higher order accuracy by applying the same low-order method to an error equation and then adding in the resulting defect to correct the solution. Our focus is not on solving the error equation to increase the order of accuracy, but on rewriting the solver as an iterative Picard integral equation solver. In doing so, our chief finding is that it is not the low-order solver that picks up the order of accuracy with each correction, but it is the underlying quadrature rule of the right hand side function that is solely responsible for picking up additional orders of accuracy. Our proofs point to a total of three sources of errors that SDC methods carry: the error at the current time point, the error from the previous iterate, and the numerical integration error that comes from the total number of quadrature nodes used for integration. The second of these two sources of errors is what separates SDC methods from Picard integral equation methods; our findings indicate that as long as difference between the current and previous iterate always gets multiplied by at least a constant multiple of the time step size, then high-order accuracy can be found even if the underlying "solver" is inconsistent the underlying ODE. From this vantage, we solidify the prospects of extending spectral deferred correction methods to a larger class of solvers to which we present some examples.

446. Leveraging Partnerships to Care for Babies Born to Mothers after Maternal Zika Infection—US Virgin Islands (USVI)

BackgroundSince February 2016, the US Virgin Islands Department of Health (VIDOH) has been monitoring the Zika outbreak and its effects on maternal and child health. As of March 19, 2018, the territory reported 291 women with confirmed laboratory evidence of Zika virus during pregnancy. Residents had limited access to the recommended pediatric screenings and specialty services related to Zika virus disease. VIDOH requested technical assistance from Centers for Disease Control and Prevention, Health Resources and Services Administration, Family Voices, and American Academy of Pediatrics to provide these services in the USVI in March 2018.MethodsVIDOH staff called 291 mothers, connected with 148, and scheduled 114 appointments. The clinic set-up included: two intake, four neurology, threeophthalmology, one audiology, one developmental, child life team, and two exit stations. Infants received comprehensive neurology, developmental, ophthalmology, and audiology examinations and were connected to resources such as Infant and Toddlers: Early Intervention services, Act Early: Learn the Signs, Disability Rights of the Virgin Islands and local specialized physicians. A data abstraction team of six reviewed charts for accuracy and abstracted data into both the US Zika pregnancy registry forms and the local Zika database.ResultsThe visiting specialists evaluated 88 infants; 65 (73.9%) in St. Thomas and 23 (26.1%) in St. Croix, 84 (73.7%) appointments and four walk-ins. There were 53 (60.2%) males and 35 (39.8%) females. Seven (7.9%) infants were 0–2 months, 18 (20.5%) were 3–6 months, 38 (43.2%) were 7–12 months, 25 (28.4%) were 13–24 months. Fifty-eight (65.9%) infants were referred for further follow-up; 35 (60.3%) to an audiologist, 20 (34.5%) to Infants and Toddlers program, 11 (19%) to a neurologist, 10 (17.2%) to an ophthalmologist, 8 (13.8%) to a developmental pediatrician, 8 (13.8%) for physical therapy, four (6.9%) for speech therapy, three(5.2%) for neuroimaging, three(5.2%) for occupational therapy, and 2 (3.4%) to an otorhinolaryngologists.ConclusionProbable hearing loss was the chief finding in many of the infants screened. Further evaluation on these infants has been recommended based on clinical guidance for infants exposed to Zika virus infection. This can help to identify the types of hearing loss associated with Zika infection in utero.Disclosures All authors: No reported disclosures.

Differentiation of access management services at seaport terminals: Facilitating potential improvements for road hauliers

Plagued by congestion and long turnaround times, road hauliers' access to seaport terminals suffers from inefficient seaport terminal and haulier operations, poor information flows between hauliers and seaport terminals and a lack of high-quality, real-time data. To address hauliers' poor access management at seaport terminals, five access management services provided by different seaport terminals worldwide were identified as part of an ongoing conversation about such services. This paper offers new insights to both scholars and practitioners by differentiating the services according to the elements of turnaround time, access reliability, access precision and access flexibility, characteristics of which were identified during a review of relevant literature. The potential impacts of the elements for each access management service were investigated during empirical studies involving six semi-structured interviews and two workshops with participants (i.e. two hauliers and a seaport terminal). The chief finding is that access management services able to exchange information in real time have greater potential to improve access management for road hauliers.

The Failure of Historians to Engage with Recent Economic Thought: The Case of Millmow

The narrative that follows is a review essay of Alex Millmow’s A History of Australasian Economic Thought (2017). The chief finding is that Millmow fails to devote sufficient attention to the history of economic theory in the last decades of the twentieth century because of his preoccupation with the history of economic policy. This is demonstrated, in part, by considering the extent to which Millmow appraises the work of those prominent modern economists who are identified in an informal survey of ten respondents.

The Mass Psychology of Classroom Discourse

AbstractIn a majority of cases observed in classrooms over the last several decades, what has gone by the name “discussion” is not discussion, but rather an interaction better known as recitation. If one sees this phenomenon as a problem, then an aspect of its resolution must be theoretical (as opposed to empirical or pedagogical): What series of conceptual terms might we adopt such that recitation does not pass for discussion? Such a theoretical response would have to address internal and external, or subjective and intersubjective, phenomena to describe what it means to participate in an interaction like discussion or recitation. Next the theory would have to explain the differences between interactions such as discussion and recitation in robust terms. Finally, these robust differences would have to prevent the “mistaking” of discussion for recitation, and vice versa. David Backer sets out to accomplish these three goals in the following essay. The theory he builds relies on a distinction between two psychological‐affective states: dehiscence and melancholia. Backer argues that recitation forms a mass through melancholic introjection of a single object, while discussion forms a group that dehiscently introjects no particular object at all. The chief finding of this essay is that viewing discussion and recitation through the mass‐psychological lens offers a new way to examine what kind of relations of influence and power form during classroom discourse and, specifically, the political significance of those discourses.

Cocaine occupancy of sigma1 receptors and dopamine transporters in mice.

Activation of sigma1 (σ1) receptors contributes to the behavioral and toxic effects of (-)-cocaine. We studied a key step, the ability of (-)-cocaine to occupy σ1 receptors in vivo, using CD-1(®) mice and the novel radioligand [(125) I]E-N-1-(3'-iodoallyl)-N'-4-(3",4"-dimethoxyphenethyl)-piperazine ([(125) I]E-IA-DM-PE-PIPZE). (-)-Cocaine displayed an ED50 of 68 μmol/kg for inhibition of specific radioligand binding in whole brain, with values between 73 and 80 μmol/kg for heart, lung, and spleen. For comparison, an ED50 of 26 μmol/kg for (-)-cocaine occupancy of striatal dopamine transporters (DAT) was determined by inhibition of [(125) I]3β-(4-iodophenyl)tropan-2β-carboxylic acid isopropyl ester ([(125) I]RTI-121) binding. A chief finding is the relatively small potency difference between (-)-cocaine occupancy of σ1 receptors and the DAT, although the DAT occupancy is likely underestimated. Interactions of (-)-cocaine with σ1 receptors were assessed further using [(125) I]E-IA-DM-PE-PIPZE for regional cerebral biodistribution studies and quantitative ex vivo autoradiography of brain sections. (-)-Cocaine binding to cerebral σ1 receptors proved directly proportional to the relative site densities known for the brain regions. Nonradioactive E-IA-DM-PE-PIPZE gave an ED50 of 0.23 μmol/kg for occupancy of cerebral σ1 receptors, and a 3.16 μmol/kg (i.p.) dose attenuated (-)-cocaine-induced locomotor hyperactivity by 30%. This effect did not reach statistical significance, but suggests that E-IA-DM-PE-PIPZE is a probable σ1 receptor antagonist. As groundwork for the in vivo studies, we used standard techniques in vitro to determine ligand affinities, site densities, and pharmacological profiles for the σ1 and σ2 receptors expressed in CD-1(®) mouse brain.

Costly Voluntary Disclosure in a Screening Game

We conduct an experimental analysis of pretrial bargaining, while allowing for the costly voluntary disclosure of private information in a screening game. In this game, the theoretical prediction is that costly voluntary disclosures will not occur. This hinges on the prediction that the person making the offer will extract all the joint surplus of settlement from the player making the costly disclosure. If concerns about fairness or reciprocity prevent this from occurring, then we may observe costly disclosures when none are predicted to occur. Our chief finding is that plaintiffs with a strong case reveal their private information 42% of the time, when the theoretical prediction is that they should do so 0% of the time. Fairness considerations appear to be important in explaining the deviation from theory. For a plaintiff with a strong case, the return to revealing private information is approximately zero, while theory predicts that this return should be negative.

Costly voluntary disclosure in a screening game

We conduct an experimental analysis of pretrial bargaining, while allowing for the costly voluntary disclosure of private information in a screening game. In this game, the theoretical prediction is that costly voluntary disclosures will not occur. This hinges on the prediction that the person making the offer will extract all the joint surplus of settlement from the player making the costly disclosure. If fairness considerations prevent this from occurring, then we may observe costly disclosures when none are predicted to occur. Our chief finding is that plaintiffs with a strong case reveal their private information 42% of the time, when the theoretical prediction is that they should do so 0% of the time. Fairness considerations appear to be important in explaining the deviation from theory. For a plaintiff with a strong case, the return to revealing private information is approximately zero, while theory predicts that this return should be negative.

Evaluating the predictions of objective intelligibility metrics for modified and synthetic speech

Several modification algorithms that alter natural or synthetic speech with the goal of improving intelligibility in noise have been proposed recently. A key requirement of many modification techniques is the ability to predict intelligibility, both offline during algorithm development, and online, in order to determine the optimal modification for the current noise context. While existing objective intelligibility metrics (OIMs) have good predictive power for unmodified natural speech in stationary and fluctuating noise, little is known about their effectiveness for other forms of speech. The current study evaluated how well seven OIMs predict listener responses in three large datasets of modified and synthetic speech which together represent 396 combinations of speech modification, masker type and signal-to-noise ratio. The chief finding is a clear reduction in predictive power for most OIMs when faced with modified and synthetic speech. Modifications introducing durational changes are particularly harmful to intelligibility predictors. OIMs that measure masked audibility tend to over-estimate intelligibility in the presence of fluctuating maskers relative to stationary maskers, while OIMs that estimate the distortion caused by the masker to a clean speech prototype exhibit the reverse pattern.

Unpacking the invisible knapsack: The invention of white privilege pedagogy

AbstractThis article uses Ricoeur’s hermeneutics of suspicion, an interpretive strategy directed to the hidden or repressed meanings behind texts, to examine the origins of white privilege pedagogy, in particular their foundational technique, “unpacking the invisible knapsack.” This article’s chief finding is that this pedagogy, though designed to fight racism, has the unintended effect of supporting white privilege. Teaching whites to “unpack their invisible knapsack” does not make them more willing to take action against racial inequality. On the contrary, it makes them more complacent, more at home in an unjust world, and more comfortable with their whiteness. White privilege pedagogy does this by focusing on personal identity (whites’ personal identity) over institutional structures, by paying more attention to whites’ experiences than to blacks’, by falsely claiming that the confession of white privileges leads to social action beneficial to blacks, and by restoring and expanding whites’ sense of mor...

Current Demographics in Large Corporate Law Firms in South Africa

By contrast with the judges and the advocates, the issue of race and gender representivity in the attorneys segment of the legal profession generally and in large corporate law firms specifically has not received significant attention, in part due to the lack of accurate statistics and a thin research tradition. Addressing the gap, a 2013 survey investigated the demographics of legal professionals in large corporate law firms in South Africa. The chief finding of the survey is that South Africa’s major corporate law firms are still dominated by white men, especially in their upper echelons. Further, nearly half of the African women professionally employed in large corporate law firms (48.1%) are candidate attorneys, which is to say non-admitted legal professionals. These findings are consistent with the few earlier studies that have been conducted and indicate the need for further detailed research into the social dynamics of the African legal profession.

Douglas Irwin on Peddling Protectionism: A Review Essay

The narrative that follows is a review essay of Douglas A. Irwin’s Peddling Protectionism: Smoot–Hawley and the Great Depression (2011). Although no attempt is made to review the literature devoted to modern trade policy in a systematic fashion, Irwin’s book is placed in recent historical and intellectual context. One chief finding is that Irwin’s research agenda is, in part, a product of a larger intellectual project led by Jagdish Bhagwati in which the case for free trade is further advanced on the grounds that commercial policy is often designed for the benefit of the few rather than the many. Another chief finding is that Irwin’s account of the Smoot–Hawley tariff is sufficiently comprehensive, if not definitive, that there is a danger that his account will completely displace the earlier major tract devoted to this episode, namely, Elmar Eric Schattschneider’s Politics, Pressure and the Tariff (1935). It is argued that Schattschneider’s 1935 account of the Smoot–Hawley tariff constitutes an important contribution to the economics of pressure group activity and is systematically misrepresented in the secondary literature.

Relationships between specific leaf area and leaf composition in succulent and non-succulent species of contrasting semi-desert communities in south-eastern Spain

Much attention has been paid to differences in leaf form and composition among vegetation types, but less to the frequently substantial variation within vegetation types. We focused on the extent to which correlations between variables are the same in both succulent-poor and succulent-rich vegetation in semi-arid SE Spain. Mean foliar [N] of perennials varied among species over a 5-fold range. Across species, [N] was positively correlated with specific leaf area (i.e., leaf area divided by dry mass; SLA) and with water concentration at saturation (WCS) in the grasslands, excluding the one succulent species. In succulent-rich vegetation on marl, SLA was correlated with [N] but not WCS, and there was a wedge-shaped relationship between [N] and WCS. Foliar [N] and [P] were positively correlated in the grasslands, but not in succulent-rich vegetation on marl. The N/P quotient varied from 8 to 29, with mean 14 in grassland on limestone and mean 26 in grassland on deep soil over gypsum. Our chief finding is that most correlations among SLA, WCS, [N] and [P] found in the non-succulent vegetation are not found in the succulent-rich vegetation. The results are discussed in relation to global patterns and the problems of defining succulence.

Training Induces Cognitive Bias

Training-induced cognitive bias may affect performance. Using a simulation-based emergency airway curriculum, we tested the hypothesis that curriculum design would induce bias and affect decision making. Twenty-three novice anesthesiology residents were randomized into 2 groups. The primary outcome measure was the initiation of supraglottic airway and cricothyroidotomy techniques in a simulated cannot-ventilate, cannot-intubate scenario during 3 evaluation sessions. Secondary outcomes were response times for device initiation. After a baseline evaluation and didactic lecture, residents received an initial practical training in either surgical cricothyroidotomy (CRIC group) or supraglottic airway (SGA group). After the midtest, the groups switched to receive the alternate training. From baseline to midtest, the SGA group increased initiation of supraglottic airway but not cricothyroidotomy. The CRIC group increased initiation of cricothyroidotomy but not supraglottic airway. After completion of training in both techniques, the SGA group increased initiation of both supraglottic airway and cricothyroidotomy. In contrast, the CRIC group increased initiation of cricothyroidotomy but failed to change practice in supraglottic airway. Final test response times showed that the CRIC group was slower to initiate supraglottic airway and faster to initiate cricothyroidotomy. Practical training in only 1 technique caused bias in both groups despite a preceding didactic lecture. The chief finding was an asymmetrical effect of training sequence even after training in both techniques. Initial training in cricothyroidotomy caused bias that did not correct despite subsequent supraglottic airway training. Educators must be alert to the risk of inducing cognitive bias when designing curricula.

The demographics of military children and families.

Since the advent of the all-volunteer force in the 1970s, marriage, parenthood, and family life have become commonplace in the U.S. military among enlisted personnel and officers alike, and military spouses and children now outnumber service members by a ratio of 1.4 to 1. Reviewing data from the government and from academic and nonacademic research, Molly Clever and David R. Segal find several trends that distinguish today's military families. Compared with civilians, for example, service members marry younger and start families earlier. Because of the requirements of their jobs, they move much more frequently than civilians do, and they are often separated from their families for months at a time. And despite steady increases since the 1970s in the percentage of women who serve, the armed forces are still overwhelmingly male, meaning that the majority of military parents are fathers. Despite these distinguishing trends, Clever and Segal's chief finding is that military families cannot be neatly pigeonholed. Instead, they are a strikingly diverse population with diverse needs. Within the military, demographic groups differ in important ways, and the service branches differ from one another as well. Military families themselves come in many forms, including not only the categories familiar from civilian life--two-parent, single-parent, and so on--but also, unique to the military, dual-service families in which both parents are service members. Moreover, military families' needs change over time as they move through personal and military transitions. Thus the best policies and programs to help military families and children are flexible and adaptable rather than rigidly structured.

Distribution of the etiological factors and symptoms of true aneurysms of subclavian and axillary arteries

Results Chief complaint was ischemic symptoms in 2 (25%) patients, non-disturbing mass in 3 (38%), feeling of compression in 2 (25%) and bleeding in 1 (12%) patient. Etiological factors include atherosclerosis in 5 patients (62%), a probable connective tissue disorder in 1 patient (13%) and idiopathic in 2 patients (25%). In these last 2 patients no atherosclerotic changes were prominent histopathologically and no other factors were identified; thus considered as idiopathic. One patient with a probable connective tissue disorder had no histopathological diagnosis. But he was phenotypically marfanoid and his past medical history was significant for surgery due to iliac artery aneurysm. Contrasted CT examination revealed no other aneurismatic segment preoperatively. Past medical history of another patient was also significant for surgery of contralateral axillary artery aneurysm. But histopathologic examination revealed atherosclerotic changes. Therefore this patient was not considered as having connective tissue disorder. One patient with ruptured axillary artery aneurysm was operated on emergently with a chief finding of bleeding. Conclusion

Protocol for a Systematic Review: Behavioral, Psychological, Educational, and Vocational Interventions to Facilitate Employment Outcomes for Cancer Survivors

Protocol for a Systematic Review: Behavioral, Psychological, Educational, and Vocational Interventions to Facilitate Employment Outcomes for Cancer Survivors