Policy Poisoning in Batch Learning for Linear Quadratic Control Systems via State Manipulation

In this work, we study policy poisoning through state manipulation, also known as sensor spoofing, and focus specifically on the case of an agent forming a control policy through batch learning in a linear-quadratic (LQ) system. In this scenario, an attacker aims to trick the learner into implementing a targeted malicious policy by manipulating the batch data before the agent begins its learning process. An attack model is crafted to carry out the poisoning strategically, with the goal of modifying the batch data as little as possible to avoid detection by the learner. We establish an optimization framework to guide the design of such policy poisoning attacks. The presence of bi-linear constraints in the optimization problem requires the design of a computationally efficient algorithm to obtain a solution. Therefore, we develop an iterative scheme based on the Alternating Direction Method of Multipliers (ADMM) which is able to return solutions that are approximately optimal. Several case studies are used to demonstrate the effectiveness of the algorithm in carrying out the sensor-based attack on the batch-learning agent in LQ control systems.Comment: First appeared at CISS 202

Reducing Poverty in California…Permanently

If California were to seriously commit to equalizing opportunity and reducing poverty, how might that commitment best be realized? This is of course a hypothetical question, as there is no evidence that California is poised to make such a serious commitment, nor have many other states gone much beyond the usual lip-service proclamations. There are many reasons for California’s complacency, but an important one is that most people think that poverty is intractable and that viable solutions to it simply don’t exist. When Californians know what needs to be done, they tend to go forward and get it done. When, for example, the state’s roads are in disrepair, there are rarely paralyzing debates about exactly how to go about fixing them; instead we proceed with the needed repairs as soon as the funds to do so are appropriated. The same type of sure and certain prescription might appear to be unavailable when it comes to reducing poverty. It is hard not to be overwhelmed by the cacophony of voices yielding a thick stream of narrow-gauge interventions, new evaluations, and piecemeal proposals.1 Although the research literature on poverty is indeed large and may seem confusing, recent advances have in fact been so fundamental that it is now possible to develop a science-based response to poverty. In the past, the causes of poverty were not well understood, and major interventions, such as the War on Poverty, had to be built more on hunch than science. It is an altogether different matter now. The causes of poverty are well established, and the effects of many possible policy responses to poverty are likewise well established. The simple purpose of this essay is to assemble these advances into a coherent plan that would, if implemented, reduce poverty in California substantially

A palaeovegetation and diatom record of tropical montane forest fire, vegetation and hydroseral changes on Mount Kenya from 27,000–16,500 cal yr BP

Fire is an important ecological disturbance in moist tropical forests influencing vegetation composition and structure. Contemporary and historical records of forest fires in mountain forests of Kenya are limited to the past decades and have a strong anthropogenic influence for ignition patterns and fire suppression activities. Palaeoenvironmental geoarchives provide the temporal depth to investigate long-term (multidecadal-to-millennial) changes in fire activity. Here we use a sediment record from the Rumuiku wetland, located in a volcanic crater on the eastern flank of Mount Kenya that was radiocarbon dated and analysed for diatom, pollen and charcoal subfossils to produce a highly resolved time series of local hydroclimatic change, vegetation, and fire; respectively. This study focuses on the time during and following the global Last Glacial Maximum, a time of rapid warming and changing regional hydroclimate with relatively stable atmospheric CO2 and not yet intensive anthropogenic modification of ecosystems. Charcoal and pollen data support associated changes in vegetation-fire centred around 21,500 cal yr BP when Afromontane forests with predominant abundances of Juniperus, Podocarpus and other montane forest trees changed to Hagenia-dominated forests that are relatively more open and adapted to burn more frequently but with less intense fires. These transitions in ecosystem composition, distribution and structure support the important role of fire in driving and maintaining forest composition in the watershed and contributing to the spatial complexity of forests around the mountain. These changes in composition, structure and biomass occurred during a time of rapid Late Pleistocene climate warming, regional hydroclimatic drying, and slowly rising atmospheric CO2 from 27,000 to 16,500 cal yr BP, during and following the conditions of the global Last Glacial Maximum. Temperature, hydroclimate and atmospheric CO2 are well-known drivers of montane vegetation change in the tropics and the role of fire is shown here to be a contributing driver to the spatial heterogeneity of forest patches at long time scales. Vegetation modelling at spatial scales relevant to land management and conservation should include retrospective evidence of the range of drivers of ecological disturbance regimes

Planning for Implementation Success Using RE-AIM and CFIR Frameworks: A Qualitative Study

Background: RE-AIM (Reach, Effectiveness, Adoption, Implementation, Maintenance) and CFIR (Consolidated Framework for Implementation Research) dissemination and implementation frameworks define theory-based domains associated with the adoption, implementation and maintenance of evidence-based interventions. Used together, the two frameworks identify metrics for evaluating implementation success, i.e., high reach and effectiveness resulting in sustained practice change (RE-AIM), and modifiable factors that explain and enhance implementation outcomes (CFIR). We applied both frameworks to study the implementation planning process for a technology-delivered asthma care intervention called Breathewell within an integrated care organization. The goal of the Breathewell intervention is to increase the efficiency of delivering resource-intensive asthma care services. Methods: We reviewed historical documents (i.e., meeting agendas; minutes) from 14 months of planning to evaluate alignment of implementation team priorities with RE-AIM domains. Key content was extracted and analyzed on topics, frequency and amount of discussion within each RE-AIM domain. Implementation team members were interviewed using questions adapted from the CFIR Interview Guide Tool to focus their reflection on the process and contextual factors considered during pre-implementation planning. Documents and transcripts were initially coded using RE-AIM domain definitions, and recoded using CFIR constructs, with intent to help explain how team decisions and actions can contribute to adoption, implementation and maintenance outcomes. Results: Qualitative analysis of team documents and interviews demonstrated strong alignment with the RE-AIM domains: Reach, Effectiveness, and Implementation; and with the CFIR constructs: formal inclusion of provider and staff stakeholders in implementation planning, compatibility of the intervention with workflows and systems, and alignment of the intervention with organizational culture. Focus on these factors likely contributed to RE-AIM outcomes of high implementation fidelity. However, team members expressed low confidence that Breathewell would be adopted and maintained post-trial. A potential explanation was weak alignment with several CFIR constructs, including tension for change, relative priority, and leadership engagement that contribute to organizational receptivity and motivation to sustain change. Conclusions: While RE-AIM provides a practical framework for planning and evaluating practice change interventions to assure their external validity, CFIR explains why implementation succeeded or failed, and when used proactively, identifies relevant modifiable factors that can promote or undermine adoption, implementation, and maintenance.Ye

Obesity Prevalence and Dietary Factors Among Preschool-Aged Head Start Children in Remote Alaska Native Communities: Baseline Data from the ‘‘Got Neqpiaq?’’ Study

Background: American Indian and Alaska Native preschool-aged children experience a high prevalence of obesity, yet are underrepresented in obesity prevention research. This study examined obesity prevalence and dietary risk factors among Alaska Native preschool-aged children in southwest Alaska. Methods: The study used baseline data from ‘‘Got Neqpiaq?’’ a culturally centered multilevel intervention focused on Yup’ik Alaska Native children, aged 3–5 years, enrolled in Head Start in 12 communities in southwest Alaska (n = 155). The primary outcomes were BMI percentile, overweight, and obesity. Dietary factors of interest were measured using biomarkers: traditional food intake (nitrogen stable isotope ratio biomarker), ultraprocessed food intake (carbon stable isotope ratio biomarker), and vegetable and fruit intake (skin carotenoid status biomarker measured by the Veggie Meter). Cardiometabolic markers (glycated hemoglobin [HbA1c] and blood cholesterol) were also measured. Results: Among the Yup’ik preschool-aged children in the study, the median BMI percentile was 91, and the prevalence of overweight or obesity was 70%. The traditional food intake biomarker was negatively associated with BMI, whereas the ultraprocessed foods and vegetable and fruit biomarkers were not associated with BMI. HbA1c and blood cholesterol were within healthy levels. Conclusions: The burden of overweight and obesity is high among Yup’ik preschool-aged children. Traditional food intake is inversely associated with BMI, which underscores the need for culturally grounded interventions that emphasize traditional values and knowledge to support the traditional food systems in Alaska Native communities in southwest Alaska. Registered with ClinicalTrials.gov #NCT03601299.Ye

An interdisciplinary knowledge translation intervention in long-term care: Study protocol for the vitamin D and osteoporosis study (ViDOS) pilot cluster randomized controlled trial

BACKGROUND: Knowledge translation (KT) research in long-term care (LTC) is still in its early stages. This protocol describes the evaluation of a multifaceted, interdisciplinary KT intervention aimed at integrating evidence-based osteoporosis and fracture prevention strategies into LTC care processes. METHODS AND DESIGN: The Vitamin D and Osteoporosis Study (ViDOS) is underway in 40 LTC homes (n = 19 intervention, n = 21 control) across Ontario, Canada. The primary objectives of this study are to assess the feasibility of delivering the KT intervention, and clinically, to increase the percent of LTC residents prescribed ≥800 IU of vitamin D daily. Eligibility criteria are LTC homes that are serviced by our partner pharmacy provider and have more than one prescribing physician. The target audience within each LTC home is the Professional Advisory Committee (PAC), an interdisciplinary team who meets quarterly. The key elements of the intervention are three interactive educational sessions led by an expert opinion leader, action planning using a quality improvement cycle, audit and feedback reports, nominated internal champions, and reminders/point-of-care tools. Control homes do not receive any intervention, however both intervention and control homes received educational materials as part of the Ontario Osteoporosis Strategy. Primary outcomes are feasibility measures (recruitment, retention, attendance at educational sessions, action plan items identified and initiated, internal champions identified, performance reports provided and reviewed), and vitamin D (≥800 IU/daily) prescribing at 6 and 12 months. Secondary outcomes include the proportion of residents prescribed calcium supplements and osteoporosis medications, and falls and fractures. Qualitative methods will examine the experience of the LTC team with the KT intervention. Homes are centrally randomized to intervention and control groups in blocks of variable size using a computer generated allocation sequence. Randomization is stratified by home size and profit/nonprofit status. Prescribing data retrieval and analysis are performed by blinded personnel. DISCUSSION: Our study will contribute to an improved understanding of the feasibility and acceptability of a multifaceted intervention aimed at translating knowledge to LTC practitioners. Lessons learned from this study will be valuable in guiding future research and understanding the complexities of translating knowledge in LTC. TRIAL REGISTRATION: ClinicalTrials.gov NCT01398527

Inactivation of DltA Modulates Virulence Factor Expression in Streptococcus pyogenes

D-alanylated lipoteichoic acid is a virtually ubiquitous component of gram-positive cell walls. Mutations in the dltABCD operon of numerous species exhibit pleiotropic effects, including reduced virulence, which has been attributed to increased binding of cationic antimicrobial peptides to the more negatively charged cell surface. In this study, we have further investigated the effects that mutating dltA has on virulence factor expression in Streptococcus pyogenes.Isogenic Delta dltA mutants had previously been created in two distinct M1T1 isolates of S. pyogenes. Immunoblots, flow cytometry, and immunofluorescence were used to quantitate M protein levels in these strains, as well as to assess their ability to bind complement. Bacteria were tested for their ability to interact with human PMN and to grow in whole human blood. Message levels for emm, sic, and various regulatory elements were assessed by quantitative RT-PCR. Cell walls of Delta dltA mutants contained much less M protein than cell walls of parent strains and this correlated with reduced levels of emm transcripts, increased deposition of complement, increased association of bacteria with polymorphonuclear leukocytes, and reduced bacterial growth in whole human blood. Transcription of at least one other gene of the mga regulon, sic, which encodes a protein that inactivates antimicrobial peptides, was also dramatically reduced in Delta dltA mutants. Concomitantly, ccpA and rofA were unaffected, while rgg and arcA were up-regulated.This study has identified a novel mechanism for the reduced virulence of dltA mutants of Streptococcus pyogenes in which gene regulatory networks somehow sense and respond to the loss of DltA and lack of D-alanine esterification of lipoteichoic acid. The mechanism remains to be determined, but the data indicate that the status of D-alanine-lipoteichoic acid can significantly influence the expression of at least some streptococcal virulence factors and provide further impetus to targeting the dlt operon of gram-positive pathogens in the search for novel antimicrobial compounds

Psychosocial Needs of Children in Foster Care and the Impact of Sexual Abuse

Children in family foster care, especially those who have experienced sexual abuse, require a safe and nurturing environment in which their psychosocial needs are met. However, there is limited knowledge on how youth prioritize various needs and what impact previous experiences have on these needs. In this study, we asked youth (formerly) in family foster care to indicate their psychosocial needs, and analyzed if youth with a history of sexual abuse have different needs. A Q methodological study was conducted with 44 youth (age 16–28). Fifteen of them reported sexual abuse during their childhood. Using by-person factor analyses, respondents who share similar subjective views were grouped together. Qualitative interpretations of the factors show differences and similarities between and within the two groups, related to help from others, being independent, processing the past, and working toward the future. Although the needs of youth with and without experiences of sexual abuse seem mostly similar, one group of sexually abused youth specifically indicated not wanting an emotional connection to foster parents, but instead a strictly instrumental, professional relationship. This study captured the diverse perspectives of youth themselves, revealing that children in foster care differ with regard to what they consider as (most) important safety, belonging, self-esteem and self-actualization needs