Sequential presentation protects working memory from catastrophic interference

Neural network models of memory are notorious for catastrophic interference: old items are forgotten as new items are memorized (e.g., French, 1999; McCloskey & Cohen, 1989). While Working Memory (WM) in human adults shows severe capacity limitations, these capacity limitations do not reflect neural-network style catastrophic interference. However, our ability to quickly apprehend the numerosity of small sets of objects (i.e., subitizing) does show catastrophic capacity limitations, and this subitizing capacity and WM might reflect a common capacity. Accordingly, computational investigations (Knops, Piazza, Sengupta, Eger, & Melcher, 2014; Sengupta, Surampudi, & Melcher, 2014) suggest that mutual inhibition among neurons can explain both kinds of capacity limitations as well as why our ability to estimate the numerosity of larger sets is limited according to a Weber ratio signature. Based on simulations with a saliency map-like network and mathematical proofs, we provide three results. First, mutual inhibition among neurons leads to catastrophic interference when items are presented simultaneously. The network can remember a limited number of items, but when more items are presented, the network forgets all of them. Second, if memory items are presented sequentially rather than simultaneously, the network remembers the most recent items rather than forgetting all of them. Hence, the tendency in WM tasks to sequentially attend even to simultaneously presented items might not only reflect attentional limitations, but an adaptive strategy to avoid catastrophic interference. Third, the mean activation level in the network can be used to estimate the number of items in small sets, but does not accurately reflect the number of items in larger sets. Rather, we suggest that the Weber ratio signature of large number discrimination emerges naturally from the interaction between the limited precision of a numeric estimation system and a multiplicative gain control mechanism

Landauer's principle in multipartite open quantum system dynamics

We investigate the link between information and thermodynamics embodied by Landauer's principle in the open dynamics of a multipartite quantum system. Such irreversible dynamics is described in terms of a collisional model with a finite temperature reservoir. We demonstrate that Landauer's principle holds, for such a configuration, in a form that involves the flow of heat dissipated into the environment and the rate of change of the entropy of the system. Quite remarkably, such a principle for {\it heat and entropy power} can be explicitly linked to the rate of creation of correlations among the elements of the multipartite system and, in turn, the non-Markovian nature of their reduced evolution. Such features are illustrated in two exemplary cases.Comment: 5 pages, 3 figures, RevTeX4-1; Accepted for publication in Phys. Rev. Let

Disruptive Effects of the Coronavirus – Errors of Commission and of Omission?

It is increasingly evident that the coronavirus disease, COVID-19, is more than a health problem; it is and will continue to adversely affect work and workplaces, education, families and social engagements, political and environmental dimensions, and financial indicators. Apart from its health ramifications, the crisis is revealing serious challenges in the global supply chain. Those difficulties are, at least in part, consequences of unwise, short-sighted business decisions made over the course of decades to outsource and downsize

Our Wicked Problem

The Coronavirus is more than a health problem. It is a “wicked” problem disrupting work, education, travel, politics, financial indicators, and more. This label came about in 1973 to help describe a special class of situations that are volatile, uncertain and ambiguous, often difficult to recognize, and difficult or impossible to solve because of incomplete, contradictory, and changing requirements. There is no clear problem definition due to interdependencies so the problem cannot be fully understood until after the solution comes about

Increasing Post-Acute and Long Term Care Coding for Advance Care Planning in an Outpatient Setting

Today’s healthcare landscape is saturated with an aging U.S. population that is living longer and with more chronic conditions. One way to manage care for this aging population, especially those with chronic conditions, is through advance care planning (ACP). Healthcare providers are capable of engaging patients in these important healthcare discussions, yet use of methods to appropriately document and code for these services are lacking. There are Current Procedural Terminology (CPT) codes in existence that would be applicable for these services; however, they are not widely understood nor routinely used in clinical practice. Administrators at a large Midwestern healthcare organization’s home based primary care program (HBPC) recognized this gap in care delivery and were open to a quality improvement initiative to address this clinical problem. The purpose of this project was to close this practice gap by establishing a standardized documentation protocol using CPT codes for ACP services. A retrospective chart analysis of all patients enrolled in the HBPC program (N=430) determined that ACP is a major aspect of care delivery at HBPC, with a total of 98% (n=419) of the total patient population having a documented resuscitation order and 81% (n=347) of patients having a documented durable power of attorney; two crucial aspects of any ACP discussion. A second chart audit (n=28) based on a simple random sampling of patients enrolled in HBPC in the last 60 days was completed to focus on CPT code utilization and associated documentation for ACP services. None of the charts in the second chart audit included the use of ACP CPT codes or the associated documentation. Ten charts did include documentation on time spent on ACP services, and therefore were used to create a projected return on investment (ROI) for ACP CPT codes. The projected ROI for ACP CPT codes found that HBPC missed opportunities on 22 relative value units and reimbursement of $1,234.30 on 10 single face-to-face patient encounters where ACP was discussed because ACP CPT codes and correct documentation were not utilized. The second chart audit strengthened the need for an educational session with clinical staff to promote the use of a standardized documentation protocol using CPT codes for ACP services. An educational session was completed with staff to identify staff knowledge and attitude regarding ACP services codes and included a pre/post-education survey. The mean score for the pre-survey was 9.4; with one being strongly disagree to five being strongly agree for a total of five questions adding up to 25. The mean score for the post-survey was 19.3. In comparing the two scores, the post-survey score increased by 39.6% representing a small to medium effect size statistically. This revealed that staff knowledge and attitude regarding CPT codes for ACP services had a positive change following the educational session. A final chart audit using a convenience sample of patients with an ACP discussion three weeks after the education session (n=55) was completed to assess for changes in documentation for ACP services. Documentation requirements that align with the CMS (2016) requirements for ACP CPT codes did not significantly improve following the educational session. Despite the lack of significant change in documentation, the educational session was still beneficial for staff knowledge regarding ACP CPT codes. Additionally, both chart audits identified three variables (consent, explanation of advance directives, and time spent on ACP discussions) that were most likely to be missed in documentation. This strengthened the need for continued employee education regarding implementation of CPT codes for ACP services as well as a standardized documentation protocol to guide providers through the implementation process in the future. Upon completion of this project, a standardized documentation protocol for ACP services now exists at the HBPC practice. This scholarly project has major implications for practice. The estimated return on investment from the use of CPT codes for ACP services highlighted the potential increase in relative value units for provider productivity as well as increases in reimbursement (for a standard fee-for-service model) captured by utilizing these codes. The educational session received support from the staff, and educational materials from the session can be utilized for future practice. Finally, the protocol will help to standardize workflow around ACP services, which are a large component of routine patient care delivery at HBPC. A standardized documentation protocol using CPT codes for advance care planning is one way to address the current gap in practice and promote quality, cost-effective care delivery at a home based primary care program

Effects of International Service Learning on Development of Intercultural Competence

As the United States becomes an increasingly multicultural society (Colby & Ortman, 2014; Perez & Hirschman, 2009), there are greater opportunities for cross-culture interactions, especially in settings for healthcare practitioners. The profession of occupational therapy demands future practitioners understand culture and become skilled in the delivery of culturally competent care (AOTA, 2014). The purpose of this study was to examine the effects of international service learning (ISL) on the development of intercultural competence in graduate occupational therapy students. Inquiry for this research followed a mixed-methods explanatory sequential design. Study participants were graduate occupational therapy students who engaged in an international service-learning experience. The quantitative data were collected utilizing a self-report measure, the intercultural developmental inventory (IDI; Hammer, 1999, 2009, 2011). This instrument is aligned with the developmental model of intercultural sensitivity (DMIS; Bennett, 1986, 1993), and identifies specific orientations that range from an ethnocentric mindset to a more ethnorelative, or intercultural mindset. The qualitative data were collected through semi-structured interviews and reflective journals, examining the participants’ perceptions about the ISL experience and the development of intercultural competence. Grounded theory data analysis protocols were utilized to systematically analyze the qualitative data and further explain the quantitative findings

Facilitators' Perspectives on the Place of Offenders in Restorative Justice: a Grounded Theory Approach

This study sought to explore and develop a preliminary, yet substantive understanding of the ways in which the offender’s position within a Restorative Justice process is influenced and impacted by the wider system around them. In an RJ conference, a facilitator conducts a structured meeting between offenders, victims, and both supporters, to allow them to understand the consequences of an offence and decide how best to repair the harm. Little research has so far investigated the experience of getting to RJ conferences for offenders or considers how other participants may be positioning them within the wider system. The current study comprises fourteen semi-structured interviews with facilitators, managers, and offenders about their experiences with RJ conferences. Data was analysed using Constructivist Grounded Theory (Charmaz, 2014). A model was constructed which described the funnelling process of an offender moving towards or being excluded from attending a conference. Whether an offender made it to conference appeared to be most affected by an over-arching philosophy of victim-focus, the focus of the RJ system, the facilitators beliefs, the offenders’ motivations and relative powerlessness, and the victims’ motivations and perceived need for protection. Repairing harm is not easy in postmodern industrialized Western societies, even with the use of programmes designed to facilitate this. The findings of this study reveal just some of the difficulties with bringing in concepts of repair to a criminal justice system and a culture which is not necessarily used to focusing on community and restoration

Enhancing electrochemical intermediate solvation through electrolyte anion selection to increase nonaqueous Li-O2_2 battery capacity

Among the 'beyond Li-ion' battery chemistries, nonaqueous Li-O$_2$ batteries have the highest theoretical specific energy and as a result have attracted significant research attention over the past decade. A critical scientific challenge facing nonaqueous Li-O$_2$ batteries is the electronically insulating nature of the primary discharge product, lithium peroxide, which passivates the battery cathode as it is formed, leading to low ultimate cell capacities. Recently, strategies to enhance solubility to circumvent this issue have been reported, but rely upon electrolyte formulations that further decrease the overall electrochemical stability of the system, thereby deleteriously affecting battery rechargeability. In this study, we report that a significant enhancement (greater than four-fold) in Li-O$_2$ cell capacity is possible by appropriately selecting the salt anion in the electrolyte solution. Using $^7$Li nuclear magnetic resonance and modeling, we confirm that this improvement is a result of enhanced Li$^+$ stability in solution, which in turn induces solubility of the intermediate to Li$_2$O$_2$ formation. Using this strategy, the challenging task of identifying an electrolyte solvent that possesses the anti-correlated properties of high intermediate solubility and solvent stability is alleviated, potentially providing a pathway to develop an electrolyte that affords both high capacity and rechargeability. We believe the model and strategy presented here will be generally useful to enhance Coulombic efficiency in many electrochemical systems (e.g. Li-S batteries) where improving intermediate stability in solution could induce desired mechanisms of product formation.Comment: 22 pages, 5 figures and Supporting Informatio

Algorithmic Bayesian Persuasion

Persuasion, defined as the act of exploiting an informational advantage in order to effect the decisions of others, is ubiquitous. Indeed, persuasive communication has been estimated to account for almost a third of all economic activity in the US. This paper examines persuasion through a computational lens, focusing on what is perhaps the most basic and fundamental model in this space: the celebrated Bayesian persuasion model of Kamenica and Gentzkow. Here there are two players, a sender and a receiver. The receiver must take one of a number of actions with a-priori unknown payoff, and the sender has access to additional information regarding the payoffs. The sender can commit to revealing a noisy signal regarding the realization of the payoffs of various actions, and would like to do so as to maximize her own payoff assuming a perfectly rational receiver. We examine the sender's optimization task in three of the most natural input models for this problem, and essentially pin down its computational complexity in each. When the payoff distributions of the different actions are i.i.d. and given explicitly, we exhibit a polynomial-time (exact) algorithm, and a "simple" $(1-1/e)$-approximation algorithm. Our optimal scheme for the i.i.d. setting involves an analogy to auction theory, and makes use of Border's characterization of the space of reduced-forms for single-item auctions. When action payoffs are independent but non-identical with marginal distributions given explicitly, we show that it is #P-hard to compute the optimal expected sender utility. Finally, we consider a general (possibly correlated) joint distribution of action payoffs presented by a black box sampling oracle, and exhibit a fully polynomial-time approximation scheme (FPTAS) with a bi-criteria guarantee. We show that this result is the best possible in the black-box model for information-theoretic reasons

Memory Aware Synapses: Learning what (not) to forget

Humans can learn in a continuous manner. Old rarely utilized knowledge can be overwritten by new incoming information while important, frequently used knowledge is prevented from being erased. In artificial learning systems, lifelong learning so far has focused mainly on accumulating knowledge over tasks and overcoming catastrophic forgetting. In this paper, we argue that, given the limited model capacity and the unlimited new information to be learned, knowledge has to be preserved or erased selectively. Inspired by neuroplasticity, we propose a novel approach for lifelong learning, coined Memory Aware Synapses (MAS). It computes the importance of the parameters of a neural network in an unsupervised and online manner. Given a new sample which is fed to the network, MAS accumulates an importance measure for each parameter of the network, based on how sensitive the predicted output function is to a change in this parameter. When learning a new task, changes to important parameters can then be penalized, effectively preventing important knowledge related to previous tasks from being overwritten. Further, we show an interesting connection between a local version of our method and Hebb's rule,which is a model for the learning process in the brain. We test our method on a sequence of object recognition tasks and on the challenging problem of learning an embedding for predicting $$ triplets. We show state-of-the-art performance and, for the first time, the ability to adapt the importance of the parameters based on unlabeled data towards what the network needs (not) to forget, which may vary depending on test conditions.Comment: ECCV 201