The effect of ice rubble on ice-ice sliding

Ice deformation processes in the Arctic can generate ice rubble. Many situations arise where ice fragments of varying size separate sea ice floes. While the shear forces between sea ice floes in direct contact with each other are controlled by ice-ice friction, what is not known is how the slip of the floes is affected by the presence of rubble between the sliding surfaces. We present the result of field experiments undertaken on sea ice in the Barents Sea. A doubledirect-shear experiment was done on floating sea ice in the field, with the addition of rubble ice between the sliding surfaces. This was achieved by pulling a floating ice block through a cut channel of open water 3m long, where broken ice filled the gap between the block and the channel sides. The displacement of the block and the force needed to move the block were measured. The time that the block was held motionless to allow the rubble to consolidate was recorded - this ranged from seconds to several hours. We found that the 'hold time' controls the maximum force needed to move the block. The relation between hold time and force is highly non-linear from which we deduce thermal consolidation is the controlling mechanism

A profile of UK doctoral candidates in social work and social care

One important indication of the strength of a discipline is the state of its doctoral research. An important milestone for the official recognition of social work in the UK has been its inclusion in Economic and Social Research Council (ESRC) doctoral funding schemes. The current study assesses the longer-term impact of these schemes, via a 2013 survey, following up a previous one in 2008. A web-based survey of social work doctoral candidates in the UK (n = 216) was conducted, to profile student demographics, research topics, methods, challenges of and supports for doctoral work. Most doctoral candidates (70 per cent) were using a primarily qualitative research strategy and only 4 per cent were using a primarily quantitative approach. Social work doctoral candidates were slightly less satisfied with their research degree programme than the general population of doctoral students. Key areas of similarity with the 2008 survey included the demographical profile (gender, age, ethnicity) and the percentage who were qualified social workers; key differences included increased percentages of candidates who were registered full time, funded by the ESRC and doing a Ph.D., as opposed to a professional doctorate. The findings highlight a need for capacity building in quantitative research methods and improved support for this academic community

De-noising of galaxy optical spectra with autoencoders

Optical spectra contain a wealth of information about the physical properties and formation histories of galaxies. Often though, spectra are too noisy for this information to be accurately retrieved. In this study, we explore how machine learning methods can be used to de-noise spectra and increase the amount of information we can gain without having to turn to sample averaging methods such as spectral stacking. Using machine learning methods trained on noise-added spectra - SDSS spectra with Gaussian noise added - we investigate methods of maximising the information we can gain from these spectra, in particular from emission lines, such that more detailed analysis can be performed. We produce a variational autoencoder (VAE) model, and apply it on a sample of noise-added spectra. Compared to the flux measured in the original SDSS spectra, the model values are accurate within 0.3-0.5 dex, depending on the specific spectral line and S/N. Overall, the VAE performs better than a principle component analysis (PCA) method, in terms of reconstruction loss and accuracy of the recovered line fluxes. To demonstrate the applicability and usefulness of the method in the context of large optical spectroscopy surveys, we simulate a population of spectra with noise similar to that in galaxies at $z = 0.1$ observed by the Dark Energy Spectroscopic Instrument (DESI). We show that we can recover the shape and scatter of the MZR in this "DESI-like" sample, in a way that is not possible without the VAE-assisted de-noising.Comment: 14 pages, 10 figures, 6 tables, accepted for publication in MNRA

De-noising of galaxy optical spectra with autoencoders

Optical spectra contain a wealth of information about the physical properties and formation histories of galaxies. Often though, spectra are too noisy for this information to be accurately retrieved. In this study, we explore how machine learning methods can be used to de-noise spectra and increase the amount of information we can gain without having to turn to sample averaging methods such as spectral stacking. Using machine learning methods trained on noise-added spectra - SDSS spectra with Gaussian noise added - we investigate methods of maximising the information we can gain from these spectra, in particular from emission lines, such that more detailed analysis can be performed. We produce a variational autoencoder (VAE) model, and apply it on a sample of noise-added spectra. Compared to the flux measured in the original SDSS spectra, the model values are accurate within 0.3-0.5 dex, depending on the specific spectral line and S/N. Overall, the VAE performs better than a principle component analysis (PCA) method, in terms of reconstruction loss and accuracy of the recovered line fluxes. To demonstrate the applicability and usefulness of the method in the context of large optical spectroscopy surveys, we simulate a population of spectra with noise similar to that in galaxies at z = 0.1 observed by the Dark Energy Spectroscopic Instrument (DESI). We show that we can recover the shape and scatter of the MZR in this ‘DESI-like’ sample, in a way that is not possible without the VAE-assisted de-noising

Solar proton effects on austral ozone during the final months of 1989

Intense solar activity during 1989 prompted six major particle events. Four of these occurred between August and December. Energetic solar protons are a natural source of ozone depletion due to the nitric oxides they produce in the polar atmospheres. In particular, modelling (Reid et al., 1991) of an event that peaked on October 20 (with greater than 10 MeV proton flux of 73000 particles sq cm s(exp -1) ster(exp -1) yields 55 percent column density enhancements of NO over the southern polar cap. Total column ozone data from the total ozone ,mapping spectrometer (TOMS) instrument aboard the Nimbus 7 satellite used at times when solar illumination facilitates measurements by TOMS over the entire southern polar regions. The impact of odd nitrogen enhancements on the spatial extent of low total column ozone and of the total ozone mass, over a region August to December. Comparisons are made with previous years (1984 to 1988) of moderate solar activity. The effect, if any, of these events on ozone during times of heterogeneous chlorine chemistry and dynamic processes is discussed

The effect of ice rubble on ice-ice sliding

Ice deformation processes in the Arctic can generate ice rubble. Many situations arise where ice fragments of varying size separate sea ice floes. While the shear forces between sea ice floes in direct contact with each other are controlled by ice-ice friction, what is not known is how the slip of the floes is affected by the presence of rubble between the sliding surfaces. We present the result of field experiments undertaken on sea ice in the Barents Sea. A double-direct-shear experiment was done on floating sea ice in the field, with the addition of rubble ice between the sliding surfaces. This was achieved by pulling a floating ice block through a cut channel of open water 3m long, where broken ice filled the gap between the block and the channel sides. The displacement of the block and the force needed to move the block were measured. The time that the block was held motionless to allow the rubble to consolidate was recorded - this ranged from seconds to several hours. We found that the 'hold time' controls the maximum force needed to move the block. The relation between hold time and force is highly non-linear from which we deduce thermal consolidation is the controlling mechanism

The effects of social service contact on teenagers in England

Objective: This study investigated outcomes of social service contact during teenage years. Method: Secondary analysis was conducted of the Longitudinal Survey of Young People in England (N = 15,770), using data on reported contact with social services resulting from teenagers’ behavior. Outcomes considered were educational achievement and aspiration, mental health, and locus of control. Inverse-probability-weighted regression adjustment was used to estimate the effect of social service contact. Results: There was no significant difference between those who received social service contact and those who did not for mental health outcome or aspiration to apply to university. Those with contact had lower odds of achieving good exam results or of being confident in university acceptance if sought. Results for locus of control were mixed. Conclusions: Attention is needed to the role of social services in supporting the education of young people in difficulty. Further research is needed on the outcomes of social services contact

Use of linked administrative children’s social care data for research: a scoping review of existing UK studies

Increasing access to children’s social care data presents enormous potential for research and policy evaluation, with opportunities increased where data can be anonymously linked to other sources of information, such as health and education data. The purpose of this scoping review was to provide an overview of all UK data linkage studies that have used routinely collected individual-level children’s social care administrative data. Six research databases were searched and twenty-five studies were identified as meeting the inclusion criteria, with the majority (n = 18) based on English data. Complexities and the time-consuming nature of these studies are highlighted, as are issues with missing data and inconsistencies in recording information across local authorities, impacting on the linkage process. Increased access to such data, and improvements to data capture, could improve the utility of these valuable administrative data assets in the social care sector

Sea Ice Dynamics: The Role Of Broken Ice In Multi-scale Deformation

Realistic models of Arctic Ocean behaviour should capture the influence of broken ice acting as a fault gouge between sliding floes. We performed double-direct shear friction tests on floating saline ice floes in the HSVA ARCTECLAB, Large Model Basin, Hamburg. We have focused these experiments on angularity and size to determine fault gouge characteristics. In our experiments the displacements and deformation of ice gouge were characterized during on-going frictional slip for the first time. Both stable sliding and stickslip behaviour were displayed. It appears that there are controls on behaviour according to gouge angularity. By measuring local stress, strain and acoustic emissions along the sliding interfacial fault we have captured the mechanics of the propagation of slip from slip initiation to dynamic propagation for the first time in the presence of broken ice

Choice in the context of informal care-giving

Extending choice and control for social care service users is a central feature of current English policies. However, these have comparatively little to say about choice in relation to the informal carers of relatives, friends or older people who are disabled or sick. To explore the realities of choice as experienced by carers, the present paper reviews research published in English since 1985 about three situations in which carers are likely to face choices: receiving social services; the entry of an older person to long-term care; and combining paid work and care. Thirteen electronic databases were searched, covering both the health and social care fields. Databases included: ASSIA; IBSS; Social Care Online; ISI Web of Knowledge; Medline; HMIC Sociological Abstracts; INGENTA; ZETOC; and the National Research Register. The search strategy combined terms that: (1) identified individuals with care-giving responsibilities; (2) identified people receiving help and support; and (3) described the process of interest (e.g. choice, decision-making and self-determination). The search identified comparatively few relevant studies, and so was supplemented by the findings from another recent review of empirical research on carers' choices about combining work and care. The research evidence suggests that carers' choices are shaped by two sets of factors: one relates to the nature of the care-giving relationship; and the second consists of wider organisational factors. A number of reasons may explain the invisibility of choice for carers in current policy proposals for increasing choice. In particular, it is suggested that underpinning conceptual models of the relationship between carers and formal service providers shape the extent to which carers can be offered choice and control on similar terms to service users. In particular, the exercise of choice by carers is likely to be highly problematic if it involves relinquishing some unpaid care-giving activities