Scalable Successive-Cancellation Hardware Decoder for Polar Codes

Polar codes, discovered by Ar{\i}kan, are the first error-correcting codes with an explicit construction to provably achieve channel capacity, asymptotically. However, their error-correction performance at finite lengths tends to be lower than existing capacity-approaching schemes. Using the successive-cancellation algorithm, polar decoders can be designed for very long codes, with low hardware complexity, leveraging the regular structure of such codes. We present an architecture and an implementation of a scalable hardware decoder based on this algorithm. This design is shown to scale to code lengths of up to N = 2^20 on an Altera Stratix IV FPGA, limited almost exclusively by the amount of available SRAM

Medication use by early-stage breast cancer survivors: a 1-year longitudinal study.

PurposeThe aim of this study is to characterize the patterns of medication use by early-stage breast cancer (ESBC) survivors from diagnosis to 1 year post-chemotherapy.MethodsA single-center longitudinal study was conducted with ESBC patients diagnosed between December 2011 and June 2014. Data on the medication use of individual patients were retrieved from prescription databases, supplemented by records from the National Electronic Health Records. The data covered the period from ESBC diagnosis to 1 year post-chemotherapy. Medication types were classified according to the World Health Organization's Anatomical Therapeutic Chemical classification system, and medication for chronic diseases was created by adapting a list of 20 chronic diseases provided by the U.S. Department of Human and Health Services.ResultsOf the 107 patients involved in the study (mean age 51.1 ± 8.4 years; 78.5 % Chinese), 46.7 % manifested non-cancer comorbidities, of which hypertension (24.3 %) was the most prevalent, followed by hyperlipidemia (13.1 %) and diabetes (5.6 %). Calcium channel blockers (12.1 %) and lipid-modifying agents (11.2 %) were the most common chronic medication types used before chemotherapy, and their use persisted during chemotherapy (10.3 and 11.2 %, respectively) and after chemotherapy (11.2 and 13.1 %, respectively). Hormonal therapy was the predominant post-chemotherapy medication (77.6 %). A statistically significant increase (p < 0.0001) was observed in the mean number of chronic disease medication classes prescribed to patients between the pre-chemotherapy (0.53 ± 1.04) and chemotherapy (0.62 ± 1.08) periods and between the chemotherapy and post-chemotherapy (1.63 ± 1.35) periods.ConclusionsThere is an increase in trend of chronic medication usage in breast cancer survivors after cancer treatment. This study provides important insights into the design of medication management programs tailored to this population. Future studies should incorporate a control population to improve the interpretation of study results

Unitary and Vilenkin's wave functions

It is remarkably difficult to reconcile unitary and Vilenkin's wave function. For example, the natural conserved inner product found in quantum unimodular gravity applies to the Hartle-Hawking wave function, but fails for its Vilenkin counterpart. We diagnose this failure from different angles (Laplace transform instead of Fourier transform, non-Hermiticity of the Hamiltonian, etc) to conclude that ultimately it stems from allowing the connection to become imaginary in a section of its contour. In turn this is the unavoidable consequence of representing the Euclidean theory as an imaginary image within a fundamentally Lorentzian theory. It is nonetheless possible to change the underlying theory and replace the connection's foray into the imaginary axis by an actual signature change (with the connection, action and Hamiltonian remaining real). The structural obstacles to unitarity are then removed, but special care must still be taken, because the Euclidean theory {\it a priori} has boundaries, so that appropriate boundary conditions are required for unitarity. Reflecting boundary conditions would reinstate a Hartle-Hawking-like solution in the Lorentzian regime. To exclude an incoming wave in the Lorentzian domain one must allow a semi-infinite tower of spheres in the Euclidean region, wave packets travelling through successive spheres for half an eternity in unimodular time. Such "Sisyphus" boundary condition no longer even vaguely resembles Vilenkin's original proposal.Comment: 13 pages, 7 figure

Ethical perspectives on advances in biogerontology

Worldwide populations are aging with economic development as a result of public health initiatives and advances in therapeutic discoveries. Since 1850, life expectancy has advanced by 1 year for every four. Accompanying this change is the rapid development of anti‐aging science. There are three schools of thought in the field of aging science. One perspective is the life course approach, which considers that aging is a good and natural process to be embraced as a necessary and positive aspect of life, where the aim is to improve the quality of existing lifespan and “compress” morbidity. Another view is that aging is undesirable, and that rejuvenation and indeed immortality are possible since the biological basis of aging is understood, and therefore, strategies are possible for engineering negligible senescence. Finally, a hybrid approach is that life span can be extended by anti‐aging medicines but with uncertain effects on health. While these advances offer much promise, the ethical perspectives are seldom discussed in cross‐disciplinary settings. This article discusses some of the key ethical issues arising from recent advances in biogerontology

Efficient Protection of Many-to-One Communications

International audienceThe dependability of a network is its ability to cope with failures , i.e., to maintain established connections even in case of failures. IP routing protocols (such as OSPF and RIP) do not fit the dependability objectives of today applications. Moreover, forwarding techniques based on destination address (like IP) induce many-to-one connections. If a dependable connection is needed, all primary paths and protections having the same destination must be established in a coordinated way. In this paper, we propose a fault recovery for many-to-one connections based on a cold (preplanned) protection. The main advantage of our approach is that the recovery in case of failures is achieved within a short delay. Additionally, with respect to other approaches, the dependability of the routing scheme is increased in the way that it statistically copes with many failures. The algorithm we propose computes an efficient backup for an arbitrary primary tree using an improved multi-tree algorithm

Learning by chance: Investigating gaps in transgender care education amongst family medicine, endocrinology, psychiatry and urology residents

Background: The transgender (trans) population is one of the most underserved in health care.  Not only do they face discrimination and stigma from society as a whole, they also have difficulty accessing transition-related care, leading to adverse outcomes such as suicide. We aimed to increase understanding on how our current postgraduate education system contributes to a lack of care for trans patients. Methods: Our study consisted of 11 semi-structured interviews conducted in 2016 with residents in the following specialties: family medicine (3), endocrinology (3), psychiatry (3), and urology (2). We used Framework Analysis to qualitatively analyze our data. Results: Residents described a lack of trans care education in the core curriculum, in part due to a lack of exposure to experts in this area. They also expressed discomfort when dealing with trans patients, due to inexperience and lack of knowledge. Furthermore, residents in each specialty had false assumptions that other specialties had sufficient knowledge and expertise in trans care. Discussion: This study highlights how the lack of teaching and clinical experiences with trans patients during residency contributes to the poor access to healthcare. By systematically embedding trans care in the curriculum, medical education can play a prominent role in addressing the healthcare disparities of this underserved population

Prospective Physicians’ Intention to Adopt Artificial Intelligence: A Configurational Perspective

Artificial intelligence (AI) drives transformation across medical specialities, requiring current and future generations of physicians to navigate ever-changing digital environments. In this context, prospective physicians will play a key role in adopting and applying AI-based health technologies, underlining the importance of understanding their knowledge, attitudes, and intentions toward AI. To dissociate corresponding profiles, we adopted a configurational perspective and conducted a two-stage survey study of 184 (t_0) and 138 (t_1) medical students at a Canadian medical school. Our principal findings corroborate the existence of distinct clusters in respondents’ AI profiles. We refer to these profiles as the AI unfamiliar, the AI educated, and the AI positive, showing that each profile is associated with different intentions towards future AI use. These exploratory insights on the variety of AI profiles in prospective physicians underline the need for targeted and adaptive measures of education and outreach