Hypergraphs, the Qualitative Solvability of κ · λ = 0, and Volterra Multipliers for Nonlinear Dynamical Systems

AbstractCertain sign equivalence classes of n-dimensional nonlinear dynamical systems correspond to n-vertex hypergraphs, The global stability of some such dynamical systems can be guaranteed if the associated hypergraphs have a simplicity of structure and meet certain quantitative path product conditions. A purely algebraic version of the same problem can be described as follows. Suppose we are given a rectangular matrix pattern of signs; each entry in the matrix is +, −, or 0. For every real matrix κ of the same sign pattern, is there a real vector λ, each component of which is positive, such that κ · λ = 0? This paper presents graph theoretic sufficient conditions on a hypergraph generated from the sign pattern of κ which guarantee the existence of λ. For κ with more highly connected hypergraphs, this paper also presents sufficient qualitative conditions on the sign pattern of κ and certain quantitative conditions on sums of hypergraph path products which together guarantee the existence of λ

Zeevruchten: Microplastics op je bord?

Onze samenleving lijdt aan een ‘plastic passion’. Plastic is werkelijk overal. Tot in zeevruchten tref je minuscule stukjes plastic, zogenaamde microplastics, aan. Microplastics is de naam voor stukjes plastic kleiner dan 5mm. Soms zijn ze zo gemaakt, denk maar aan de plastic pellets als grondstof gebruikt in de plasticindustrie of als schuurparels in verzorgingscrubs. Maar microplastics kunnen ook ontstaan door het uiteenvallen van grote stukken plastic afval of bij het wassen van synthetische kledij. Je vindt deze plastic vezeltjes en stukjes in onder andere mosselen en Noordzeegarnalen. De aanwezigheid van microplastics in ons voedsel haalt vaak het nieuws en zorgt voor ongerustheid bij de liefhebbers van al het lekkers uit zee. Maar moeten we ons ook echt zorgen maken

Entanglement-assisted quantum low-density parity-check codes

This article develops a general method for constructing entanglement-assisted quantum low-density parity-check (LDPC) codes, which is based on combinatorial design theory. Explicit constructions are given for entanglement-assisted quantum error-correcting codes with many desirable properties. These properties include the requirement of only one initial entanglement bit, high error-correction performance, high rates, and low decoding complexity. The proposed method produces several infinite families of codes with a wide variety of parameters and entanglement requirements. Our framework encompasses the previously known entanglement-assisted quantum LDPC codes having the best error-correction performance and many other codes with better block error rates in simulations over the depolarizing channel. We also determine important parameters of several well-known classes of quantum and classical LDPC codes for previously unsettled cases

Jellyfish swarms and degree of exposure and vulnerabil-ity of recreational and tourist activities on beaches. Methodological approach to their assessment in the Lagos-Ferrara sector (Málaga, Spain)

An important part of the economy of the municipalities on the southern Spanish coast revolves around tourist activity, whose main attraction is the sun and beach. Events such as the arrival of swarms of jellyfish on their beaches have generated a certain amount of fear in the tourism sector. This work presents a methodological essay to evaluate the possible impact of this phenomenon on the use of the beach and the tourist economic activity linked to it. The chosen study area is the stretch of coast between the beach-es of "Lagos" and "Ferrara" (eastern coast of the province of Málaga). It is developed from a risk management perspective, addressing exposure and vulnerability factors. The sources are mainly surveys. The results show that in the short term there are no clear consequences, but there are in the long term.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

The impact of therapeutics on mortality in hospitalised patients with COVID-19:systematic review and meta-analyses informing the European Respiratory Society living guideline

Hospitalised patients with coronavirus disease 2019 (COVID-19) have a high mortality rate. There are an increasing number of published randomised controlled trials for anti-inflammatory, anti-viral and other treatments. The European Respiratory Society Living Guidelines for the Management of Hospitalised Adults with COVID-19 were published recently, providing recommendations on appropriate pharmacotherapy.Patient, Intervention, Comparator and Outcomes questions for key interventions were identified by an international panel and systematic reviews were conducted to identify randomised controlled trials meeting the inclusion criteria. The importance of end-points were rated, and mortality was identified as the key "critical" outcome for all interventions. Random-effects meta-analysis was used to pool studies and provide effect estimates for the impact of treatments on mortality.Corticosteroids, hydroxychloroquine, azithromycin, remdesivir, anti-interleukin (IL)-6 monoclonal antibodies, colchicine, lopinavir/ritonavir and interferon-β have been reviewed.Our results found further evidence in support of the use of corticosteroids, particularly dexamethasone, and anti-IL-6 receptor monoclonal antibody therapy. These data support the need to identify additional therapies with beneficial effects on mortality

Hemophilia gene therapy knowledge and perceptions: Results of an international survey

Background Hemophilia gene therapy is a rapidly evolving therapeutic approach in which a number of programs are approaching clinical development completion. Objective The aim of this study was to evaluate knowledge and perceptions of a variety of health care practitioners and scientists about gene therapy for hemophilia. Methods This survey study was conducted February 1 to 18, 2019. Survey participants were members of the ISTH, European Hemophilia Consortium, European Hematology Association, or European Association for Hemophilia and Allied Disorders with valid email contacts. The online survey consisted of 36 questions covering demographic information, perceptions and knowledge of gene therapy for hemophilia, and educational preferences. Survey results were summarized using descriptive statistics. Results Of the 5117 survey recipients, 201 responded from 55 countries (4% response rate). Most respondents (66%) were physicians, and 59% were physicians directly involved in the care of people with hemophilia. Among physician respondents directly involved in hemophilia care, 35% lacked the ability to explain the science of adeno-associated viral gene therapy for hemophilia, and 40% indicated limited ability or lack of comfort answering patient questions about gene therapy for hemophilia based on clinical trial results to date. Overall, 75% of survey respondents answered 10 single-answer knowledge questions correctly, 13% incorrectly, and 12% were unsure of the correct answers. Conclusions This survey highlighted knowledge gaps and educational needs related to gene therapy for hemophilia and, along with other inputs, has informed the development of "Gene Therapy in Hemophilia: An ISTH Education Initiative.

Low-cost consumer-based trackers to measure physical activity and sleep duration among adults in free-living conditions : validation study

Background: Wearable trackers for monitoring physical activity (PA) and total sleep time (TST) are increasingly popular. These devices are used not only by consumers to monitor their behavior but also by researchers to track the behavior of large samples and by health professionals to implement interventions aimed at health promotion and to remotely monitor patients. However, high costs and accuracy concerns may be barriers to widespread adoption. Objective: This study aimed to investigate the concurrent validity of 6 low-cost activity trackers for measuring steps, moderate-to-vigorous physical activity (MVPA), and TST: Geonaut On Coach, iWown i5 Plus, MyKronoz ZeFit4, Nokia GO, VeryFit 2.0, and Xiaomi MiBand 2. Methods: A free-living protocol was used in which 20 adults engaged in their usual daily activities and sleep. For 3 days and 3 nights, they simultaneously wore a low-cost tracker and a high-cost tracker (Fitbit Charge HR) on the nondominant wrist. Participants wore an ActiGraph GT3X+ accelerometer on the hip at daytime and a BodyMedia SenseWear device on the nondominant upper arm at nighttime. Validity was assessed by comparing each tracker with the ActiGraph GT3X+ and BodyMedia SenseWear using mean absolute percentage error scores, correlations, and Bland-Altman plots in IBM SPSS 24.0. Results: Large variations were shown between trackers. Low-cost trackers showed moderate-to-strong correlations (Spearman r=0.53-0.91) and low-to-good agreement (intraclass correlation coefficient [ICC]=0.51-0.90) for measuring steps. Weak-to-moderate correlations (Spearman r=0.24-0.56) and low agreement (ICC=0.18-0.56) were shown for measuring MVPA. For measuring TST, the low-cost trackers showed weak-to-strong correlations (Spearman r=0.04-0.73) and low agreement (ICC=0.05-0.52). The Bland-Altman plot revealed a variation between overcounting and undercounting for measuring steps, MVPA, and TST, depending on the used low-cost tracker. None of the trackers, including Fitbit (a high-cost tracker), showed high validity to measure MVPA. Conclusions: This study was the first to examine the concurrent validity of low-cost trackers. Validity was strongest for the measurement of steps; there was evidence of validity for measurement of sleep in some trackers, and validity for measurement of MVPA time was weak throughout all devices. Validity ranged between devices, with Xiaomi having the highest validity for measurement of steps and VeryFit performing relatively strong across both sleep and steps domains Low-cost trackers hold promise for monitoring and measurement of movement and sleep behaviors, both for consumers and researchers

Entanglement-assisted quantum low-density parity-check codes

This paper develops a general method for constructing entanglement-assisted quantum low-density parity-check (LDPC) codes, which is based on combinatorial design theory. Explicit constructions are given for entanglement-assisted quantum error-correcting codes (EAQECCs) with many desirable properties. These properties include the requirement of only one initial entanglement bit, high error correction performance, high rates, and low decoding complexity. The proposed method produces infinitely many new codes with a wide variety of parameters and entanglement requirements. Our framework encompasses various codes including the previously known entanglement-assisted quantum LDPC codes having the best error correction performance and many new codes with better block error rates in simulations over the depolarizing channel. We also determine important parameters of several well-known classes of quantum and classical LDPC codes for previously unsettled cases.Comment: 20 pages, 5 figures. Final version appearing in Physical Review

Marien zwerfvuil: van droeve cijfers tot hoopvolle initiatieven

Het eerste synthetische plastic (‘bakeliet’) deed zijn intrede in 1907, dankzij onze landgenoot Leo Baekeland. Nu, een dikke eeuw later, komt plastic of kunststof voor in alle vormen en maten: van verpakkingsmateriaal en drinkflessen, tot touw en kledijvezels, vaak ter vervanging van natuurlijke materialen als hout, steen, leer, metaal of glas. Maar wat in de 20ste eeuw nog beschreven werd als ‘hét wonderproduct’, zorgt nu voor een van de meest zichtbare vormen van vervuiling, op land maar zeker ook in zee..

Nonlinear superchiral meta-surfaces: tuning chirality and disentangling non-reciprocity at the nanoscale.

Circularly polarized light is incident on a nanostructured chiral meta-surface. In the nanostructured unit cells whose chirality matches that of light, superchiral light is forming and strong optical second harmonic generation can be observed