2,513 research outputs found
Practitioner perspectives on the application of palaeoecology in nature conservation
It is widely recognised that palaeoecology holds great potential to inform and support nature conservation, but that there are difficulties in knowledge exchange between academia and practitioners that inhibit the operationalisation of research. To facilitate the integration of palaeoecology into the conservation toolkit, it is essential to understand perspectives of the practitioners themselves and the contexts in which they work. This paper reports the results of a survey of 153 UK-based conservation practitioners, concerning their perceptions of palaeoecology, the barriers to its use and potential solutions for making palaeoecological insights more accessible in conservation practice. The survey was conducted online over a period of 3 months; closed question responses were analysed for statistical trends and thematic analysis was done on open question responses. The majority of respondents were strongly positive about the role palaeoecological research could play, though they also exhibited a limited understanding of how and why one might implement it. They identified time constraints as the biggest barrier to using palaeoecology within their work, and also flagged concerns around financial resources and the accessibility of the research. Access to applied case studies and a centralised database were the most favoured solutions among respondents. Respondents with prior experience of working with palaeoecology were generally more optimistic about its incorporation. This paper makes several key recommendations to progress the integration of palaeoecology into conservation, including improving data accessibility, aligning research design with conservation and policy drivers, and increasing both respective groups’ understanding of the other
Older adults, falls and technologies for independent living: a life space approach
This paper draws attention to the need for further understanding of the fine details of routine and taken-for-granted daily activities and mobility. It argues that such understanding is critical if technologies designed to mitigate the negative impacts of falls and fear-of-falling are to provide unobtrusive support for independent living. The reported research was part of a large, multidisciplinary, multi-site research programme into responses to population ageing in Ireland, Technologies for Independent Living (TRIL). A small, exploratory, qualitative life-space diary study was conducted. Working with eight community-dwelling older adults with different experiences of falls or of fear-of-falls, data were collected through weekly life-space diaries, daily-activity logs, two-dimensional house plans and a pedometer. For some participants, self-recording of their daily activities and movements revealed routine, potentially risky behaviour about which they had been unaware, which may have implications for falls-prevention advice. The findings are presented and discussed around four key themes: ‘being pragmatic’, ‘not just a faller’, ‘heightened awareness and blind spots’ and ‘working with technology’. The findings suggest a need to think creatively about how technological and other solutions best fit with people's everyday challenges and needs and of critical importance, that their installation does not reduce an older adult to ‘just a faller’ or a person with a fear-of-falls
Rates of carbonate cementation associated with sulphate reduction in DSDP/ODP sediments: implications for the formation of concretions
DSDP/ODP porewater profiles in organic carbon-bearing (<5% org. C) sediments commonly show decreases in Ca2+ concentrations and increases in alkalinity over depths where sulphate is being removed by microbial reduction. These Ca2+ depletion profiles represent the combined effect of diffusion, advection and reaction (addition by ion exchange and removal by precipitation mainly as CaCO3 and/or dolomite). A diagenetic model has been used to estimate the rate constant (k) for Ca2+ removal by precipitation during sulphate depletion over depths of 15-150 m, assuming first order kinetics. The rate constants for Ca2+ removal range from 10(-14) to 10(-11) s(-1) in 19 DSDP/ODP sediments, which span a range of bottom water temperatures (0-10 degreesC), lithologies (calcareous to clastic) and sedimentation rates (0.001-0.4 cm year(-1)). Values of k correlate with sedimentation rate (omega) such that log k=1.16 log omega-10.3, indicating that faster rates of Ca2+ removal occur at higher sedimentation rates where there are also higher degrees of saturation with respect to CaCO3 and dolomite. Depth-integrated masses of Ca2+ removed (<100 mumol cm(-2)) during sulphate depletion over these depth ranges are equivalent to a dispersed phase of approximately 1.5 wt.% CaCO3 or 3 wt.% dolomite in a compacted sediment. The complete occlusion of sediment porosity observed in concretions with isotopic signatures suggesting carbonate sourced from sulphate reduction therefore requires more time (a depositional hiatus), more rapid sulphate reduction (possibly by anaerobic methane oxidation) and/or the continued transport of isotopically light carbonate to the concretion site after sulphate reduction has ceased
Practitioner perspectives on the application of palaeoecology in nature conservation
It is widely recognised that palaeoecology holds great potential to inform and support nature conservation, but that there are difficulties in knowledge exchange between academia and practitioners that inhibit the operationalisation of research. To facilitate the integration of palaeoecology into the conservation toolkit, it is essential to understand perspectives of the practitioners themselves and the contexts in which they work. This paper reports the results of a survey of 153 UK-based conservation practitioners, concerning their perceptions of palaeoecology, the barriers to its use and potential solutions for making palaeoecological insights more accessible in conservation practice. The survey was conducted online over a period of 3 months; closed question responses were analysed for statistical trends and thematic analysis was done on open question responses. The majority of respondents were strongly positive about the role palaeoecological research could play, though they also exhibited a limited understanding of how and why one might implement it. They identified time constraints as the biggest barrier to using palaeoecology within their work, and also flagged concerns around financial resources and the accessibility of the research. Access to applied case studies and a centralised database were the most favoured solutions among respondents. Respondents with prior experience of working with palaeoecology were generally more optimistic about its incorporation. This paper makes several key recommendations to progress the integration of palaeoecology into conservation, including improving data accessibility, aligning research design with conservation and policy drivers, and increasing both respective groups’ understanding of the other
Wherever I may roam: social viscosity and kin affiliation in a wild population despite natal dispersal
Dispersal affects the social contexts individuals experience by redistributing individuals in space, and the nature of social interactions can have important fitness consequences. During the vagrancy stage of natal dispersal, after an individual has left its natal site and before it has settled to breed, social affiliations might be predicted by opportunities to associate (e.g., distance in space and time between natal points of origin) or kin preferences. We investigated the social structure of a population of juvenile great tits (Parus major) and asked whether social affiliations during vagrancy were predicted by 1) the distance between natal nest-boxes, 2) synchrony in fledge dates, and 3) accounting for spatial and temporal predictors, whether siblings tended to stay together. We show that association strength was affected predominantly by spatial proximity at fledging and, to a lesser extent, temporal proximity in birth dates. Independently of spatial and temporal effects, sibling pairs associated more often than expected by chance. Our results suggest that the structure of the winter population is shaped primarily by limits to dispersal through incomplete population mixing. In addition, our results reveal kin structure, and hence the scope for fitness-related interactions between particular classes of kin. Both spatial-mediated and socially mediated population structuring can have implications for our understanding of the evolution of sociality
Universal First-passage Properties of Discrete-time Random Walks and Levy Flights on a Line: Statistics of the Global Maximum and Records
In these lecture notes I will discuss the universal first-passage properties
of a simple correlated discrete-time sequence {x_0=0, x_1,x_2.... x_n} up to n
steps where x_i represents the position at step i of a random walker hopping on
a continuous line by drawing independently, at each time step, a random jump
length from an arbitrary symmetric and continuous distribution (it includes,
e.g., the Levy flights). I will focus on the statistics of two extreme
observables associated with the sequence: (i) its global maximum and the time
step at which the maximum occurs and (ii) the number of records in the sequence
and their ages. I will demonstrate how the universal statistics of these
observables emerge as a consequence of Pollaczek-Spitzer formula and the
associated Sparre Andersen theorem.Comment: Lecture notes for the summer school "Fundamental Problems in
Statistical Physics: XII" held at Leuven, Belgium (2009). 20 pages, 4
figures; typos corrected, a figure redrawn and new references and discussions
adde
Vortices and chirality of magnetostatic modes in quasi-2D ferrite disk particles
In this paper we show that the vortex states can be created not only in
magnetically soft "small" (with the dipolar and exchange energy competition)
cylindrical dots, but also in magnetically saturated "big" (when the exchange
is neglected) cylindrical dots. A property associated with a vortex structure
becomes evident from an analysis of confinement phenomena of magnetic
oscillations in a ferrite disk with a dominating role of magnetic-dipolar
(non-exchange-interaction) spectra. In this case the scalar
(magnetostatic-potential) wave functions may have a phase singularity in a
center of a dot. A non-zero azimuth component of the flow velocity demonstrates
the vortex structure. The vortices are guaranteed by the chiral edge states of
magnetic-dipolar modes in a quasi-2D ferrite disk
Masked Autoencoders are Scalable Learners of Cellular Morphology
Inferring biological relationships from cellular phenotypes in high-content
microscopy screens provides significant opportunity and challenge in biological
research. Prior results have shown that deep vision models can capture
biological signal better than hand-crafted features. This work explores how
self-supervised deep learning approaches scale when training larger models on
larger microscopy datasets. Our results show that both CNN- and ViT-based
masked autoencoders significantly outperform weakly supervised baselines. At
the high-end of our scale, a ViT-L/8 trained on over 3.5-billion unique crops
sampled from 93-million microscopy images achieves relative improvements as
high as 28% over our best weakly supervised baseline at inferring known
biological relationships curated from public databases. Relevant code and
select models released with this work can be found at:
https://github.com/recursionpharma/maes_microscopy.Comment: Spotlight at NeurIPS 2023 Generative AI and Biology (GenBio) Worksho
Active colloids in complex fluids
We review recent work on active colloids or swimmers, such as self-propelled
microorganisms, phoretic colloidal particles, and artificial micro-robotic
systems, moving in fluid-like environments. These environments can be
water-like and Newtonian but can frequently contain macromolecules, flexible
polymers, soft cells, or hard particles, which impart complex, nonlinear
rheological features to the fluid. While significant progress has been made on
understanding how active colloids move and interact in Newtonian fluids, little
is known on how active colloids behave in complex and non-Newtonian fluids. An
emerging literature is starting to show how fluid rheology can dramatically
change the gaits and speeds of individual swimmers. Simultaneously, a moving
swimmer induces time dependent, three dimensional fluid flows, that can modify
the medium (fluid) rheological properties. This two-way, non-linear coupling at
microscopic scales has profound implications at meso- and macro-scales: steady
state suspension properties, emergent collective behavior, and transport of
passive tracer particles. Recent exciting theoretical results and current
debate on quantifying these complex active fluids highlight the need for
conceptually simple experiments to guide our understanding.Comment: 6 figure
Why do women invest in pre-pregnancy health and care? A qualitative investigation with women attending maternity services
Background Despite the importance attributed to good pre-pregnancy care and its potential to improve pregnancy and child health outcomes, relatively little is known about why women invest in pre-pregnancy health and care. We sought to gain insight into why women invested in pre-pregnancy health and care. Methods We carried out 20 qualitative in-depth interviews with pregnant or recently pregnant women who were drawn from a survey of antenatal clinic attendees in London, UK. Interviewees were purposively sampled to include high and low investors in pre-pregnancy health and care, with variation in age, partnership status, ethnicity and pre-existing medical conditions. Data analysis was conducted using the Framework method. Results We identified three groups in relation to pre-pregnancy health and care: 1) The “prepared” group, who had high levels of pregnancy planning and mostly positive attitudes to micronutrient supplementation outside of pregnancy, carried out pre-pregnancy activities such as taking folic acid and making changes to diet and lifestyle. 2) The “poor knowledge” group, who also had high levels of pregnancy planning, did not carry out pre-pregnancy activities and described themselves as having poor knowledge. Elsewhere in their interviews they expressed a strong dislike of micronutrient supplementation. 3) The “absent pre-pregnancy period” group, had the lowest levels of pregnancy planning and also expressed anti-supplement views. Even discussing the pre-pregnancy period with this group was difficult as responses to questions quickly shifted to focus on pregnancy itself. Knowledge of folic acid was poor in all groups. Conclusion Different pre-pregnancy care approaches are likely to be needed for each of the groups. Among the “prepared” group, who were proactive and receptive to health messages, greater availability of information and better response from health professionals could improve the range of pre-pregnancy activities carried out. Among the “poor knowledge” group, better response from health professionals might yield greater uptake of pre-pregnancy information. A different, general health strategy might be more appropriate for the “absent pre-pregnancy period” group. The fact that general attitudes to micronutrient supplementation were closely related to whether or not women invested in pre-pregnancy health and care was an unanticipated finding and warrants further investigation.This report is independent research commissioned and funded by the Department of Health Policy Research Programme Pre-Pregnancy Health and Care in England: Exploring Implementation and Public Health Impact, 006/0068
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