Entropy concepts and DNA investigations

Topological and metric entropies of the DNA sequences from different organisms were calculated. Obtained results were compared each other and with ones of corresponding artificial sequences. For all envisaged DNA sequences there is a maximum of heterogeneity. It falls in the block length interval [5,7]. Maximum distinction between natural and artificial sequences is shifted on 1-3 position from the maximum of heterogeneity to the right as for metric as for topological entropy. This point on the specificity of real DNA sequences in the interval.Comment: 10 pages 7 figures submitted to PL

The Hubble flow around the CenA / M83 galaxy complex

We present HST/ACS images and color-magnitude diagrams for 24 nearby galaxies in and near the constellation of Centaurus with radial velocities V_LG < 550 km/s. Distances are determined based on the luminosities of stars at the tip of the red giant branch that range from 3.0 Mpc to 6.5 Mpc. The galaxies are concentrated in two spatially separated groups around Cen A (NGC 5128) and M 83 (NGC 5236). The Cen A group itself has a mean distance of 3.76 +/-0.05 Mpc, a velocity dispersion of 136 km/s, a mean harmonic radius of 192 kpc, and an estimated orbital/virial mass of (6.4 - 8.1) x 10^12 M_sun. This elliptical dominated group is found to have a relatively high mass-to-light ratio: M/L_B = 125 M_sun/L_sun. For the M 83 group we derived a mean distance of 4.79 +/-0.10 Mpc, a velocity dispersion of 61 km/s, a mean harmonic radius of 89 kpc, and estimated orbital/virial mass of (0.8 - 0.9) x 10^12 M_sun. This spiral dominated group is found to have a relatively low M/L_B = 34 M_sun/L_sun. The radius of the zero-velocity surface around Cen A lies at R_0 = 1.40 +/-0.11 Mpc, implying a total mass within R_0 of M_T = (6.0 +/-1.4) x 10^12 M_sun. This value is in good agreement with the Cen A virial/orbital mass estimates and provides confirmation of the relatively high M/L_B of this elliptical-dominated group. The centroids of both the groups, as well as surrounding field galaxies, have very small peculiar velocities, < 25 km/s, with respect to the local Hubble flow with H_0 = 68 km/s/Mpc.Comment: 31 pages including 9 figures and 3 tables. Accepted for publication in Astronomical Journal, 133, N0. 2 (February), 200

How notifications affect engagement with a behaviour change app: Results from a micro-randomised trial

Background: Drink Less is a behavior change app to help higher-risk drinkers in the United Kingdom reduce their alcohol consumption. The app includes a daily notification asking users to “Please complete your drinks and mood diary,” yet we did not understand the causal effect of the notification on engagement nor how to improve this component of Drink Less. We developed a new bank of 30 new messages to increase users’ reflective motivation to engage with Drink Less. This study aimed to determine how standard and new notifications affect engagement. Objective: Our objective was to estimate the causal effect of the notification on near-term engagement, to explore whether this effect changed over time, and to create an evidence base to further inform the optimization of the notification policy. Methods: We conducted a micro-randomized trial (MRT) with 2 additional parallel arms. Inclusion criteria were Drink Less users who consented to participate in the trial, self-reported a baseline Alcohol Use Disorders Identification Test score of ≥8, resided in the United Kingdom, were aged ≥18 years, and reported interest in drinking less alcohol. Our MRT randomized 350 new users to test whether receiving a notification, compared with receiving no notification, increased the probability of opening the app in the subsequent hour, over the first 30 days since downloading Drink Less. Each day at 8 PM, users were randomized with a 30% probability of receiving the standard message, a 30% probability of receiving a new message, or a 40% probability of receiving no message. We additionally explored time to disengagement, with the allocation of 60% of eligible users randomized to the MRT (n=350) and 40% of eligible users randomized in equal number to the 2 parallel arms, either receiving the no notification policy (n=98) or the standard notification policy (n=121). Ancillary analyses explored effect moderation by recent states of habituation and engagement. Results: Receiving a notification, compared with not receiving a notification, increased the probability of opening the app in the next hour by 3.5-fold (95% CI 2.91-4.25). Both types of messages were similarly effective. The effect of the notification did not change significantly over time. A user being in a state of already engaged lowered the new notification effect by 0.80 (95% CI 0.55-1.16), although not significantly. Across the 3 arms, time to disengagement was not significantly different. Conclusions: We found a strong near-term effect of engagement on the notification, but no overall difference in time to disengagement between users receiving the standard fixed notification, no notification at all, or the random sequence of notifications within the MRT. The strong near-term effect of the notification presents an opportunity to target notifications to increase “in-the-moment” engagement. Further optimization is required to improve the long-term engagement. International Registered Report Identifier (IRRID): RR2-10.2196/1869

The structural response of the cornea to changes in stromal hydration

The primary aim of this study was to quantify the relationship between corneal structure and hydration in humans and pigs. X-ray scattering data were collected from human and porcine corneas equilibrated with polyethylene glycol (PEG) to varying levels of hydration, to obtain measurements of collagen fibril diameter, interfibrillar spacing and intermolecular spacing. Both species showed a strong positive linear correlation between hydration and interfibrillar spacing2 and a non-linear, bi-phasic relationship between hydration and fibril diameter, whereby fibril diameter increased up to approximately physiological hydration, H = 3.0, with little change thereafter. Above H = 3.0, porcine corneas exhibited a larger fibril diameter than human corneas (p < 0.001). Intermolecular spacing also varied with hydration in a bi-phasic manner but reached a maximum value at a lower hydration (H = 1.5) than fibril diameter. Human corneas displayed a higher intermolecular spacing than porcine corneas at all hydrations (p < 0.0001). Human and porcine corneas required a similar PEG concentration to reach physiological hydration, suggesting that the total fixed charge that gives rise to the swelling pressure is the same. The difference in their structural responses to hydration can be explained by variations in molecular crosslinking and intra/interfibrillar water partitioning

On the characteristics of natural hydraulic dampers : an image-based approach to study the fluid flow behaviour inside the human meniscal tissue

The meniscal tissue is a layered material with varying properties influenced by collagen content and arrangement. Understanding the relationship between structure and properties is crucial for disease management, treatment development, and biomaterial design. The internal layer of the meniscus is softer and more deformable than the outer layers, thanks to interconnected collagen channels that guide fluid flow. To investigate these relationships, we propose an integrated approach that combines Computational Fluid Dynamics (CFD) with Image Analysis (CFD-IA). We analyze fluid flow in the internal architecture of the human meniscus across a range of inlet velocities (0.1 mm/s to 1.6 m/s) using high-resolution 3D micro-computed tomography scans. Statistical correlations are observed between architectural parameters (tortuosity, connectivity, porosity, pore size) and fluid flow parameters (number distribution, permeability). Some channels exhibit values of 1400 at an inlet velocity of 1.6 m/s, and a transition from Darcy’s regime to a non-Darcian regime occurs around an inlet velocity of 0.02 m/s. Location-dependent permeability ranges from 20-32 Darcy. Regression modelling reveals a strong correlation between fluid velocity and tortuosity at high inlet velocities, as well as with channel diameter at low inlet velocities. At higher inlet velocities, flow paths deviate more from the preferential direction, resulting in a decrease in the concentration parameter by an average of 0.4. This research provides valuable insights into the fluid flow behaviour within the meniscus and its structural influences. 3D models and image stack are available to download at https://doi.org/10.5281/zenodo.10401592

SafeSpot:An innovative app and mental health support package for Scottish schools - a qualitative analysis as part of a mixed methods study

Aims: The aim of the study was to investigate teachers’ and pupils’ perceptions about the effect of the SafeSpot mental health curriculum on the well‐being of young people and on their knowledge of mental health conditions. This trial intends to determine the acceptability and benefits of web and mobile technology in delivering emotional well‐being in schools, through use of the SafeSpot programme. Background: With 10% of young people aged 5 to 16 diagnosed with a mental disorder, there is pressure for schools to address their pupils’ emotional well‐being. However, many educators report that their schools have insufficient provisions and feel inadequately equipped to support pupils’ mental health. Methods: This qualitative analysis was embedded within a randomly allocated stepped‐wedge design, conducted in six West of Scotland secondary schools. A total of 2320 pupils (aged 11 to 14 years) and 90 teachers were included. Young people’s understanding of health‐seeking, and teacher’s confidence in delivering and accessing well‐being information was assessed qualitatively. Results: Qualitative analysis revealed themes highlighting the beneficial nature of SafeSpot, including pupil engagement, content of tutorials, perceived impact of SafeSpot and level of training provided for teachers. Conclusions: Web technology could potentially offer a more structured way for staff to support their pupils’ mental health, whilst reducing stigma. SafeSpot was perceived, by pupils and teachers, to be engaging

Migrant African women: tales of agency and belonging

This paper explores issues of belonging and agency among asylum seekers and refugee women of African origin in the UK. It discusses the ways these women engendered resistance in their everyday life to destitution, lack of cultural recognition, and gender inequality through the foundation of their own non-governmental organization, African Women’s Empowerment Forum, AWEF, a collective ‘home’ space. The focus of this account is on migrant women’s agency and self-determination for the exercise of choice to be active actors in society. It points to what might be an important phenomenon on how local grassroots movements are challenging the invisibility of asylum seekers’ and refugees’ lives and expanding the notion of politics to embrace a wider notion of community politics with solidarity. AWEF is the embodiment of a social space that resonates the ‘in-between’ experience of migrant life providing stability to the women members regarding political and community identification

Notifications to Improve Engagement With an Alcohol Reduction App: Protocol for a Micro-Randomized Trial (Preprint)

BACKGROUND &lt;i&gt;Drink Less&lt;/i&gt; is a behavior change app that aims to help users in the general adult population reduce hazardous and harmful alcohol consumption. The app includes a daily push notification, delivered at 11 am, asking users to “Please complete your mood and drinking diaries.” Previous analysis of &lt;i&gt;Drink Less&lt;/i&gt; engagement data suggests the current notification strongly influences how users engage with the app in the subsequent hour. To exploit a potential increase of vulnerability of excess drinking and opportunity to engage with the app in the evenings, we changed the delivery time from 11 am to 8 pm. We now aim to further optimise the content and sequence of notifications, testing 30 new evidence-informed notifications targeting the user’s perceived usefulness of the app. OBJECTIVE The primary objective is to assess whether sending a notification at 8 pm increases behavioral engagement (opening the app) in the subsequent hour. Secondary objectives include comparing the effect of the new bank of messages with the standard message and effect moderation over time. We also aim to more generally understand the role notifications have on the overall duration, depth, and frequency of engagement with &lt;i&gt;Drink Less&lt;/i&gt; over the first 30 days after download. METHODS This is a protocol for a micro-randomized trial with two additional parallel arms. Inclusion criteria are &lt;i&gt;Drink Less&lt;/i&gt; users who (1) consent to participate in the trial; (2) self-report a baseline Alcohol Use Disorders Identification Test score of 8 or above; (3) reside in the United Kingdom; (4) age ≥18 years and; (5) report interest in drinking less alcohol. In the micro-randomized trial, participants will be randomized daily at 8 pm to receive no notification, a notification with text from the new message bank, or the standard message. The primary outcome is the time-varying, binary outcome of &lt;i&gt;“Did the user open the app in the hour from 8 pm to 9 pm?”&lt;/i&gt;. The primary analysis will estimate the marginal relative risk for the notifications using an estimator developed for micro-randomized trials with binary outcomes. Participants randomized to the parallel arms will receive no notifications (Secondary Arm A), or the standard notification delivered daily at 11 am (Secondary Arm B) over 30 days, allowing the comparison of overall engagement between different notification delivery strategies. RESULTS Approval was granted by the University College of London’s Departmental Research Ethics Committee (CEHP/2016/556) on October 11, 2019, and The London School of Hygiene and Tropical Medicine Interventions Research Ethics Committee (17929) on November 27, 2019. Recruitment began on January 2, 2020, and is ongoing. CONCLUSIONS Understanding how push notifications may impact engagement with a behavior change app can lead to further improvements in engagement, and ultimately help users reduce their alcohol consumption. This understanding may also be generalizable to other apps that target a variety of behavior changes. INTERNATIONAL REGISTERED REPORT DERR1-10.2196/18690 </sec

Engagement With a Behavior Change App for Alcohol Reduction: Data Visualization for Longitudinal Observational Study (Preprint)

BACKGROUND Behavior change apps can develop iteratively, where the app evolves into a complex, dynamic, or personalized intervention through cycles of research, development, and implementation. Understanding how existing users engage with an app (eg, frequency, amount, depth, and duration of use) can help guide further incremental improvements. We aim to explore how simple visualizations can provide a good understanding of temporal patterns of engagement, as usage data are often longitudinal and rich. OBJECTIVE This study aims to visualize behavioral engagement with &lt;i&gt;Drink Less&lt;/i&gt;, a behavior change app to help reduce hazardous and harmful alcohol consumption in the general adult population of the United Kingdom. METHODS We explored behavioral engagement among 19,233 existing users of &lt;i&gt;Drink Less&lt;/i&gt;. Users were included in the sample if they were from the United Kingdom; were 18 years or older; were interested in reducing their alcohol consumption; had a baseline Alcohol Use Disorders Identification Test score of 8 or above, indicative of excessive drinking; and had downloaded the app between May 17, 2017, and January 22, 2019 (615 days). Measures of when sessions begin, length of sessions, time to disengagement, and patterns of use were visualized with heat maps, timeline plots, k-modes clustering analyses, and Kaplan-Meier plots. RESULTS The daily 11 AM notification is strongly associated with a change in engagement in the following hour; reduction in behavioral engagement over time, with 50.00% (9617/19,233) of users disengaging (defined as no use for 7 or more consecutive days) 22 days after download; identification of 3 distinct trajectories of use, namely engagers (4651/19,233, 24.18% of users), slow disengagers (3679/19,233, 19.13% of users), and fast disengagers (10,903/19,233, 56.68% of users); and limited depth of engagement with 85.076% (7,095,348/8,340,005) of screen views occurring within the &lt;i&gt;Self-monitoring and Feedback&lt;/i&gt; module. In addition, a peak of both frequency and amount of time spent per session was observed in the evenings. CONCLUSIONS Visualizations play an important role in understanding engagement with behavior change apps. Here, we discuss how simple visualizations helped identify important patterns of engagement with &lt;i&gt;Drink Less&lt;/i&gt;. Our visualizations of behavioral engagement suggest that the daily notification substantially impacts engagement. Furthermore, the visualizations suggest that a fixed notification policy can be effective for maintaining engagement for some users but ineffective for others. We conclude that optimizing the notification policy to target both effectiveness and engagement is a worthwhile investment. Our future goal is to both understand the causal effect of the notification on engagement and further optimize the notification policy within &lt;i&gt;Drink Less&lt;/i&gt; by tailoring to contextual circumstances of individuals over time. Such tailoring will be informed from the findings of our micro-randomized trial (MRT), and these visualizations were useful in both gaining a better understanding of engagement and designing the MRT. </sec

Notifications to Improve Engagement With an Alcohol Reduction App: Protocol for a Micro-Randomized Trial

Background Drink Less is a behavior change app that aims to help users in the general adult population reduce hazardous and harmful alcohol consumption. The app includes a daily push notification, delivered at 11 am, asking users to "Please complete your mood and drinking diaries." Previous analysis of Drink Less engagement data suggests the current notification strongly influences how users engage with the app in the subsequent hour. To exploit a potential increase of vulnerability of excess drinking and opportunity to engage with the app in the evenings, we changed the delivery time from 11 am to 8 pm. We now aim to further optimise the content and sequence of notifications, testing 30 new evidence-informed notifications targeting the user's perceived usefulness of the app. Objective The primary objective is to assess whether sending a notification at 8 pm increases behavioral engagement (opening the app) in the subsequent hour. Secondary objectives include comparing the effect of the new bank of messages with the standard message and effect moderation over time. We also aim to more generally understand the role notifications have on the overall duration, depth, and frequency of engagement with Drink Less over the first 30 days after download. Methods This is a protocol for a micro-randomized trial with two additional parallel arms. Inclusion criteria are Drink Less users who (1) consent to participate in the trial; (2) self-report a baseline Alcohol Use Disorders Identification Test score of 8 or above; (3) reside in the United Kingdom; (4) age ≥18 years and; (5) report interest in drinking less alcohol. In the micro-randomized trial, participants will be randomized daily at 8 pm to receive no notification, a notification with text from the new message bank, or the standard message. The primary outcome is the time-varying, binary outcome of "Did the user open the app in the hour from 8 pm to 9 pm?". The primary analysis will estimate the marginal relative risk for the notifications using an estimator developed for micro-randomized trials with binary outcomes. Participants randomized to the parallel arms will receive no notifications (Secondary Arm A), or the standard notification delivered daily at 11 am (Secondary Arm B) over 30 days, allowing the comparison of overall engagement between different notification delivery strategies. Results Approval was granted by the University College of London's Departmental Research Ethics Committee (CEHP/2016/556) on October 11, 2019, and The London School of Hygiene and Tropical Medicine Interventions Research Ethics Committee (17929) on November 27, 2019. Recruitment began on January 2, 2020, and is ongoing. Conclusions Understanding how push notifications may impact engagement with a behavior change app can lead to further improvements in engagement, and ultimately help users reduce their alcohol consumption. This understanding may also be generalizable to other apps that target a variety of behavior changes.International registered report identifier (irrid)DERR1-10.2196/18690