An event centric approach to modeling quantum systems

Event centric approaches to modeling physics have gained traction in recent decades. In this work, we present a first principles approach to this idea, which assumes nothing but the existence of causal networks of events and their relationships. The modeling elements we employ consist solely of classical bits, or the abstract symbols $0$ and $1$. Using sequences of these symbols, we model primitive elements of causal networks consisting of two causally connected events. By introducing an epistemic constraint on observers, we derive a statistical picture of these network elements, leading to the emergence of non-determinism and the subsequent derivation of a quantum theory. We then apply this event centric framework to three physical scenarios involving spin, including a Bell test. Comparing the resulting predictions to non-relativistic quantum mechanics, we find good agreement, including a violation of the CHSH inequality. More broadly, the results presented here highlight this novel framework's explanatory and predictive power. When coupled with recent advancements in event centric approaches to modeling spacetime, we argue that this framework may provide some insight into the issue of quantum gravity.Comment: 32 pages, 9 figure

Evaluating Continual Learning on a Home Robot

Robots in home environments need to be able to learn new skills continuously as data becomes available, becoming ever more capable over time while using as little real-world data as possible. However, traditional robot learning approaches typically assume large amounts of iid data, which is inconsistent with this goal. In contrast, continual learning methods like CLEAR and SANE allow autonomous agents to learn off of a stream of non-iid samples; they, however, have not previously been demonstrated on real robotics platforms. In this work, we show how continual learning methods can be adapted for use on a real, low-cost home robot, and in particular look at the case where we have extremely small numbers of examples, in a task-id-free setting. Specifically, we propose SANER, a method for continuously learning a library of skills, and ABIP (Attention-Based Interaction Policies) as the backbone to support it. We learn four sequential kitchen tasks on a low-cost home robot, using only a handful of demonstrations per task

Testing a discrete model for quantum spin with two sequential Stern-Gerlach detectors and photon Fock states

Despite its unparalleled success, quantum mechanics (QM) is an incomplete theory of nature. Longstanding concerns regarding its mathematical foundations and physical interpretation persist, a full century beyond its conception. Limited by these issues, efforts to move beyond QM have struggled to gain traction within the broader physics community. One approach to progress in this direction, which is deeply rooted in the tradition of physics, is the development of new models for physical systems otherwise treated by QM. One such model is presented here, which concerns the interaction of a spin system with sequences of two Stern-Gerlach detectors that may be independently rotated. Rather than employing the traditional formalism of QM, the proposed model is supported by tools from discrete mathematics, such as finite groups, set theory, and combinatorics. Equipped with this novel toolkit, an analog of Wigner's d-matrix formula is derived and shown to deviate slightly from QM. With these results, the proposed model is extended to an optical system involving photon number states passing through a beam splitter. Leveraging recent advancements in high precision experiments on these systems, we then propose a means of testing the new model using a tabletop experiment. Hence, the proposed model not only makes clear testable predictions, but also provides valuable insight into the essential principles of quantum theory.Comment: 20 pages, 6 figure

Transmission and Transport of Energy in the Western U.S. and Canada: A Law and Policy Road Map

This collection of short essays arose from the inaugural meeting of the Idaho Symposium on Energy in the West, which was held in November, 2014. The topic for this first Symposium was Transmission and Transport of Energy in the Western U.S. and Canada: A Law and Policy Road Map. The essays in this collection provide a notable introduction to the major energy issues facing the West today. Topics include: building a resilient legal architecture for western energy production; natural gas flaring; transmission planning for wind energy; utilities and rooftop solar; special considerations for western states and the Clean Power Plan; the Clean Power Plan\u27s implications for the western grid; siting renewable energy on public lands; and implications of utility reform in New York and Hawaii for the Northwest

QOL-26. Exploring the experience of young people receiving remotely delivered Acceptance and Commitment Therapy following treatment for a brain tumour

Despite high survival rates of children and young people diagnosed with a brain tumour, survival is often associated with poor psychological, physical, and social outcomes. Acceptance and Commitment Therapy (ACT) is an evidence-based psychological intervention shown to improve psychological and physical outcomes in adults and children with chronic disease, including cancer. The ACT Now study investigates the feasibility of ACT delivered remotely with young people who have experienced a brain tumour. This study aims to describe participant experience whilst better understanding the impact of therapy and capturing the barriers and facilitators to engagement. Participants of the ACT Now study were invited to take part in a semi-structured interview with questions covering experience of study initiation, receipt of ACT, remote delivery and overall impact of ACT. Ten participants who had previously undergone treatment for a brain tumour have been interviewed to date. Interviews were transcribed verbatim and coded into broad themes. We found that pre-therapy mood and altruism served as motivation for interviewees’ involvement in the study. Interviewees reported hoping to learn coping techniques to navigate fluctuating moods and the pressures of young adult life. Despite the technology used for remote delivery occasionally malfunctioning, interviewees reported increased ability to access therapy via this method. However, an overall preference for face-to-face therapy delivery was reported with interviewees describing that they felt communication might have been easier in person. The therapeutic relationship and the therapists’ flexible schedules were seen as facilitators to session attendance. Barriers to attendance were scarcely reported but included scheduling conflicts due to work or school. ACT was highly regarded amongst interviewees and provided an opportunity for them to learn about themselves and how they can live in accordance with their personal values. Interviewees benefitted from ACT psychologically, physically, and socially and reported an overall positive experience of study involvement

Reemergence of Endemic Chikungunya, Malaysia

Chikungunya virus infection recently reemerged in Malaysia after 7 years of nondetection. Genomic sequences of recovered isolates were highly similar to those of Malaysian isolates from the 1998 outbreak. The reemergence of the infection is not part of the epidemics in other Indian Ocean countries but raises the possibility that chikungunya virus is endemic in Malaysia

Sustained Sexual Behavior Change after Acute HIV Diagnosis in Malawi

Background Identification of acute HIV infection (AHI) allows for important opportunities for HIV prevention through behavior change and biomedical intervention. Here, we evaluate changes in sexual risk behaviors among persons with AHI enrolled in a combined behavioral and biomedical intervention designed to reduce onward transmission of HIV. Methods Participants were randomized to standard HIV counseling, a multisession behavioral intervention, or a multisession behavioral intervention plus antiretrovirals. Sexual behaviors were assessed periodically over 1 year. Results Four weeks after diagnosis, the predicted probability of reporting multiple sexual partners decreased from 24% to 9%, and the probability of reporting unprotected sex decreased from 71% to 27%. These declines in sexual risk behaviors were sustained over follow-up irrespective of study arm. Conclusions Diagnosis of AHI alone may be sufficient to achieve immediate and sustained behavior change during this highly infectious period

Incorporating Acute HIV Screening into Routine HIV Testing at Sexually Transmitted Infection Clinics, and HIV Testing and Counseling Centers in Lilongwe, Malawi

Background and Objectives:Integrating acute HIV-infection (AHI) testing into clinical settings is critical to prevent transmission, and realize potential treatment-as-prevention benefits. We evaluated acceptability of AHI testing and compared AHI prevalence at sexually transmitted infection (STI) clinics and HIV testing and counseling (HTC) clinics in Lilongwe, Malawi.Methods:We conducted HIV RNA testing for HIV-seronegative patients visiting STI and HTC clinics. AHI was defined as positive RNA and negative/discordant rapid antibody tests. We evaluated demographic, behavioral, and transmission-risk differences between STI and HTC patients and assessed performance of a risk-score for targeted screening.Results:Nearly two-thirds (62.8%, 9280/14,755) of eligible patients consented to AHI testing. We identified 59 persons with AHI (prevalence = 0.64%)–a 0.9% case-identification increase. Prevalence was higher at STI [1.03% (44/4255)] than at HTC clinics [0.3% (15/5025), P < 0.01], accounting for 2.3% of new diagnoses vs 0.3% at HTC clinic. Median viral load (VL) was 758,050 copies per milliliter; 25% (15/59) had VL ≥10,000,000 copies per milliliter. Median VL was higher at STI (1,000,000 copies/mL) compared with HTC (153,125 copies/mL, P = 0.2). Among persons with AHI, those tested at STI clinics were more likely to report genital sores compared with those tested at HTC clinics (54.6% vs 6.7%, P < 0.01). The risk score algorithm performed well in identifying persons with AHI at HTC clinics (sensitivity = 73%, specificity = 89%).Conclusions:The majority of patients consented to AHI testing. AHI prevalence was substantially higher in STI clinics than HTC clinics. Remarkably high VLs and concomitant genital scores demonstrate the potential for transmission. Universal AHI screening at STI clinics, and targeted screening at HTC centers, should be considered

Human Immunodeficiency Virus (HIV)-1 Transmission among Persons with Acute HIV-1 Infection in Malawi: Demographic, Behavioral, and Phylogenetic Relationships

Background: Understanding sexual networks involving acute human immunodeficiency virus (HIV)-1 infections (AHI) may lead to prevention opportunities to mitigate high rates of onward transmission. We evaluated HIV-1 phylogenetic and behavioral characteristics among persons with AHI and their referred partners. Methods: Between 2012 and 2014, 46 persons with AHI in Malawi participated in a combined behavioral and biomedical intervention. Participants referred sexual partners by passive referral. Demographics and sexual behaviors were collected through interviews and HIV-1 genetic relationships were assessed with phylogenetics. Results: Among 45 AHI participants with HIV-1 sequences, none was phylogenetically-linked with another AHI index. There were 19 (42%) AHI participants who referred a single partner that returned for testing. Most partners (n = 17) were HIV-infected, with 15 (88%) presenting with an established infection. There were 14 index-partner pairs that had sequences available; 13 (93%) pairs were phylogenetically-linked dyads. The AHI index was female in 7/13 (54%) dyads. Age-disparate relationships among dyads were common (≥5-year age difference in 67% of dyads), including 3/6 dyads involving a male index and a younger woman. Index participants with a referred partner were more likely to report no casual partners and to be living with their current partner than participants not in dyads. Conclusions: Passive-partner referral successfully identified partners with genetically-similar HIV infections - the likely source of infection - but only 40% of index cases referred partners who presented for HIV-1 testing. Future work evaluating assisted partner notification may help reach susceptible partners or more people with untreated HIV-1 infections connected to acute transmission. Clinical Trials Registration: NCT01450189