Minimal Betti Numbers

We give conditions for determining the extremal behavior for the (graded) Betti numbers of squarefree monomial ideals. For the case of non-unique minima, we give several conditions which we use to produce infinite families, exponentially growing with dimension, of Hilbert functions which have no smallest (graded) Betti numbers among squarefree monomial ideals and all ideals. For the case of unique minima, we give two families of Hilbert functions, one with exponential and one with linear growth as dimension grows, that have unique minimal Betti numbers among squarefree monomial ideals

Self-Wiring of Neural Networks

In order to form the intricate network of synaptic connections in the brain, the growth cones migrate through the embryonic environment to their targets using chemical communication. As a first step to study self-wiring, 2D model systems of neurons have been used. We present a simple model to reproduce the salient features of the 2D systems. The model incorporates random walkers representing the growth cones, which migrate in response to chemotaxis substances extracted by the soma and communicate with each other and with the soma by means of attractive chemotactic "feedback".Comment: 10 pages, 10 PostScript figures. Originally submitted to the neuro-dev archive which was never publicly announced (was 9710001

One-dimensional Bose chemistry: effects of non-integrability

Three-body collisions of ultracold identical Bose atoms under tight cylindrical confinement are analyzed. A Feshbach resonance in two-body collisions is described by a two-channel zero-range interaction. Elimination of the closed channel in the three-body problem reduces the interaction to a one-channel zero-range one with an energy dependent strength. The related problem with an energy independent strength (the Lieb-Liniger-McGuire model) has an exact solution and forbids all chemical processes, such as three-atom association and diatom dissociation, as well as reflection in atom-diatom collisions. The resonant case is analyzed by a numerical solution of the Faddeev-Lovelace equations. The results demonstrate that as the internal symmetry of the Lieb-Liniger-McGuire model is lifted, the reflection and chemical reactions become allowed and may be observed in experiments.Comment: 5 pages, 4 figure

Genetic consequences of improved river connectivity in brown trout (Salmo trutta L.)

Fragmentation of watercourses poses a significant threat to biodiversity, particularly for migratory fish species. Mitigation measures such as fishways, have been increasingly implemented to restore river connectivity and support fish migration. The effects of such restoration efforts are typically tested using telemetry and fisheries methods, which do not fully capture the broader population movements that may have important consequences for population viability. We performed a before-and-after control-impact (BACI) study using genetic tools (SNPs) to investigate the effect of a newly implemented fishway, aiming to enhance upstream spawning migration of brown trout (Salmo trutta Linnaeus) in a reservoir with two headwater tributaries fragmented by man-made weirs. Another reservoir with two barrier-free tributaries was also analysed as a control. Our results showed that the isolated brown trout population was spawning in the reservoir before the installation of the fishway, and we found genetic structuring and differentiation between fragmented headwater tributaries before the fishway construction, but not in the control reservoir. Unexpectedly, after the fishway construction we observed signals consistent with increased genetic differentiation between populations of newly recruited juvenile fish in the reservoir tributary and fish in the reservoir. We propose this was caused by newly enabled philopatric behaviour of brown trout to their natal spawning tributary. In contrast, we did not find any genetic changes in the tributary without a fishway or in the barrier-free reservoir system. Given the scarcity of similar studies, we advocate for an increased use of genetic analyses in BACI studies to monitor and evaluate the effect of efforts to restore habitat connectivity and inform future management strategies

Low friction droplet transportation on a substrate with a selective Leidenfrost effect

An energy saving Leidenfrost levitation method is introduced to transport micro-droplets with virtually frictionless contact between the liquid and solid substrate. By micro-engineering the heating units, selective areas of the whole substrate can be electro-thermally activated. A droplet can be levitated as a result of the Leidenfrost effect, and further transported when the substrate is tilted slightly. The selective electro-heating produces a uniform temperature distribution on the heating units within 1 s, in response to a triggering voltage. Alongside these experimental observations, finite element simulations are conducted to understand the temperature profile of the selective heated substrate, and also generate phase diagrams to verify the Leidenfrost regime for different substrate materials. Finally, we demonstrate the possibility of controlling low friction high speed droplet transportation (~ 65 mm/s) when the substrate is tilted (~ 7 °) by structurally designing the substrate. This work establishes the basis for an entirely new approach to droplet microfluidics

Economic evaluation of barriers to minimize reservoir sport fish escapement

Objective: Barriers can be an effective method for reducing escapement of reservoir sport fish; however, whether the financial benefits of a barrier outweigh the costs of a barrier is unknown. We sought to quantify the costs and benefits associated with constructing barriers to reduce fish escapement while explicitly accounting for variability and uncertainty. Methods: We developed a framework using simulation modeling and discounted cash flow techniques to quantify the costs and benefits of barrier construction on Brushy Creek Lake, Iowa, where a barrier was constructed in 2020 to reduce escapement of stocked Walleye Sander vitreus and Muskellunge Esox masquinongy. We then incorporated this framework into an interactive Shiny application to enable cost–benefit evaluations across a wide range of barrier types, system types, species, and escapement rates. Result: The present value of the parallel-bar barrier on Brushy Creek Lake, Iowa, over 10 years was US$69,576 (range =$64,484–$73,976), whereas the present value of escaped fish was$316,416 ($253,459–$378,823), indicating a net benefit of $246,840 ($188,975–$304,847) associated with barrier construction. The benefit–cost ratio of barrier construction was 4.55 after 10 years, indicating that for every$1 in present value spent on barrier construction, we saved $4.55 by preventing fish escapement. There was a 99% probability of a positive mean net benefit of the barrier after 3 years. Conclusion: Our results indicate that barriers can be a cost-effective option to minimize fish escapement, and barrier costs are more predictable compared with the cost of escapement. Quantifying the value of escaped fish and barrier construction on an economic scale enables the use of formal decision-making tools to address complicated and multifaceted issues associated with reservoir fisheries management.This article is published as Lewis, M. C., Tyndall, J. C., Dodd, B., & Weber, M. J. Economic evaluation of barriers to minimize reservoir sport fish escapement. North American Journal of Fisheries Management (2024). https://doi.org/10.1002/nafm.11009. © 2024 The Authors. This is an open access article under the terms of the Creative Commons Attribution-NonCommercial License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited and is not used for commercial purposes

Planar selective Leidenfrost propulsion without physically structured substrates or walls

The Leidenfrost effect allows droplets to be transported on a virtually frictionless layer of vapor above a superheated substrate. The substrates are normally topographically structured using subtractive techniques to produce saw-tooth, herringbone, and other patterns and bulk heated, leading to significant challenges in energy consumption and controlled operation. Here, we propose a planar lithographic approach to levitate and propel droplets using temperature profiles, which can be spatially patterned and controlled in time. We show that micro-patterned electrodes can be heated and provide control of the pressure profile and the vapor flow. Using these almost featureless planar substrates, we achieve self-directed motion of droplets, with velocities of approximately 30 mms−1, without topographically structuring the substrate or introducing physical walls. Our approach has the potential to be integrated into applications, such as digital microfluidics, where frictionless and contactless droplet transport may be advantageous

Postmemory: Fragments / Crypt

This photo essay gathers evidence of the video works Postmemory: Fragments and Postmemory: Crypt, which ran from June 27 to August 4, 2022, at Holocaust Centre North at the University of Huddersfield in northern England. Included here are photographs from the video works and their installation, as well as the complete exhibition program. In an accompanying statement, Spatz positions this work within the broader Judaica project, an extended investigation of contemporary jewish identity developed over the past decade, and in relation to the four themes suggested by the editors of this special issue: ethics, knowledge, affect, and power

Effectiveness and cost-effectiveness of a web-based cardiac rehabilitation programme for people with chronic stable angina:protocol for the ACTIVATE (Angina Controlled Trial Investigating the Value of the 'Activate your heart' Therapeutic E-intervention) randomised controlled trial

INTRODUCTION: Chronic stable angina is common and disabling. Cardiac rehabilitation is routinely offered to people following myocardial infarction or revascularisation procedures and has the potential to help people with chronic stable angina. However, there is insufficient evidence of effectiveness and cost-effectiveness for its routine use in this patient group. The objectives of this study are to compare the effectiveness and cost-effectiveness of the 'Activate Your Heart' cardiac rehabilitation programme for people with chronic stable angina compared with usual care.METHODS AND ANALYSIS: ACTIVATE is a multicentre, parallel-group, two-arm, superiority, pragmatic randomised controlled trial, with recruitment from primary and secondary care centres in England and Wales and a target sample size of 518 (1:1 allocation; allocation sequence by minimisation programme with built-in random element). The study uses secure web-based allocation concealment. The two treatments will be optimal usual care (control) and optimal usual care plus the 'Activate Your Heart' web-based cardiac rehabilitation programme (intervention). Outcome assessment and statistical analysis will be performed blinded; participants will be unblinded. Outcomes will be measured at baseline and at 6 and 12 months' follow-up. Primary outcome will be the UK version of Seattle Angina Questionnaire (SAQ-UK), physical limitations domain at 12 months' follow-up. Secondary outcomes will be the remaining two domains of SAQ-UK, dyspnoea, anxiety and depression, health utility, self-efficacy, physical activity and the incremental shuttle walk test. All safety events will be recorded, and serious adverse events assessed to determine whether they are related to the intervention and expected. Concurrent economic evaluation will be cost-utility analysis from health service perspective. An embedded process evaluation will determine the mechanisms and processes that explain the implementation and impacts of the cardiac rehabilitation programme.ETHICS AND DISSEMINATION: North of Scotland National Health Service Research Ethics Committee approval, reference 21/NS/0115. Participants will provide written informed consent. Results will be disseminated by peer-reviewed publication.TRIAL REGISTRATION NUMBER: ISRCTN10054455.</p

Study protocol: differential effects of diet and physical activity based interventions in pregnancy on maternal and fetal outcomes--individual patient data (IPD) meta-analysis and health economic evaluation.

© 2014 Ruifrok et al.; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly credited. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.BACKGROUND: Pregnant women who gain excess weight are at risk of complications during pregnancy and in the long term. Interventions based on diet and physical activity minimise gestational weight gain with varied effect on clinical outcomes. The effect of interventions on varied groups of women based on body mass index, age, ethnicity, socioeconomic status, parity, and underlying medical conditions is not clear. Our individual patient data (IPD) meta-analysis of randomised trials will assess the differential effect of diet- and physical activity-based interventions on maternal weight gain and pregnancy outcomes in clinically relevant subgroups of women. METHODS/DESIGN: Randomised trials on diet and physical activity in pregnancy will be identified by searching the following databases: MEDLINE, EMBASE, BIOSIS, LILACS, Pascal, Science Citation Index, Cochrane Database of Systematic Reviews, Cochrane Central Register of Controlled Trials, Database of Abstracts of Reviews of Effects, and Health Technology Assessment Database. Primary researchers of the identified trials are invited to join the International Weight Management in Pregnancy Collaborative Network and share their individual patient data. We will reanalyse each study separately and confirm the findings with the original authors. Then, for each intervention type and outcome, we will perform as appropriate either a one-step or a two-step IPD meta-analysis to obtain summary estimates of effects and 95% confidence intervals, for all women combined and for each subgroup of interest. The primary outcomes are gestational weight gain and composite adverse maternal and fetal outcomes. The difference in effects between subgroups will be estimated and between-study heterogeneity suitably quantified and explored. The potential for publication bias and availability bias in the IPD obtained will be investigated. We will conduct a model-based economic evaluation to assess the cost effectiveness of the interventions to manage weight gain in pregnancy and undertake a value of information analysis to inform future research. SYSTEMATIC REVIEW REGISTRATION: PROSPERO 2013: CRD42013003804.This study was funded by the National Institute for Health Research (NIHR) HTA (Health Technology Assessment) UK programme 12/01