7,056 research outputs found
Application of passive seismic to the detection of buried hollows
Pilot studies involving the use of passive seismic techniques in a range of geological settings and
applications, e.g., mapping bedrock, studies of soil erosion and Quaternary mapping have shown that it
is a versatile, non-invasive and economic technique. This paper presents the findings of three case studies
that trialled the use of passive seismic techniques for the detection and characterisation of buried hollows
in carbonate rocks, comprising: i) a buried hollow in the Cretaceous Chalk at Ashford Hill in the Kennet
Valley, a tributary of the River Thames, UK; ii) buried karst in the foundation excavations for wind turbines in Carboniferous Limestone at Brassington, Wirksworth, Derbyshire, UK, and iii) defining the extent of solution hollows that host terrestrial Miocene deposits, near Friden, Newhaven, Derbyshire, UK. Whilst case studies ii) and iii) are focused on areas of buried dolines, the geological context of the Ashford
Hill site is more complex; comprising a deformation hollow with an uplifted āpinnacleā of chalk bedrock at
the centre. The data were collected using a (Tromino), a three-component, broadband seismometer to measure background ambient noise (microtremors induced by wind, ocean waves, industrial machinery, road and rail traffic, etc.). The Tromino is small, portable with an operating range of 0.1 Hz to 1,024 Hz and interpreted using proprietary software (Grilla), which subjects the data to Fourier transformation and smoothing. Where possible, estimated shear wave velocities used in the
Grilla Software modelling, based on peaks identified on the H/V spectrum, have been calibrated using borehole data or parallel geophysical techniques. In each case, the karst features were defined by Nakamuraās
horizontal to vertical (H/V) spectral ratio technique, where microtremors are converted to show impedance
contrasts (velocity x density), or a pseudo layered seismic stratigraphy of the near surface along each
profile. An additional benefit of the use of this technique is its depth of penetration and potential for defining the
structural and lithological context of the hollows, thereby contributing to the process understanding associated with their formation. To this end the technique has helped define discontinuity (fault, joint or bedding) guidance of the hollows.S. Castellaro, Mrs J. Renwick, West Coast Energy Ltd (GDF Suez), Mr Roger Durrant (Raymond Brown Construction Ltd
The transferability of diatoms to clothing and the methods appropriate for their collection and analysis in forensic geoscience
AbstractForensic geoscience is concerned with the analysis of geological materials in order to compare and exclude environmental samples from a common source, or to identify an unknown provenance in a criminal investigation. Diatom analysis is currently an underused technique within the forensic geoscience approach, which has the potential to provide an independent ecological assessment of trace evidence. This study presents empirical data to provide a preliminary evidence base in order to be able to understand the nature of diatom transfers to items of clothing, and the collection of transferred diatom trace evidence from a range of environments under experimental conditions. Three diatom extraction methods were tested on clothing that had been in contact with soil and water sites: rinsing in water (RW), rinsing in ethanol (RE), and submersion in H2O2 solution (H). Scanning electron microscopy (S.E.M.) analysis was undertaken in order to examine the degree of diatom retention on treated clothing samples. The total diatom yield and species richness data was recorded from each experimental sample in order to compare the efficacy of each method in collecting a representative sample for analysis. Similarity was explored using correspondence analysis. The results highlight the efficiency of H2O2 submersion in consistently extracting high diatom counts with representative species from clothing exposed to both aquatic and terrestrial sites. This is corroborated by S.E.M. analysis. This paper provides an important empirical evidence base for both establishing that diatoms do indeed transfer to clothing under forensic conditions in a range of environments, and in identifying that H2O2 extraction is the most efficient technique for the optimal collection of comparative samples. There is therefore potentially great value in collecting and analysing diatom components of geoforensic samples in order to aid in forensic investigation
Neurotrophin and Wnt signaling cooperatively regulate dendritic spine formation
Dendritic spines are major sites of excitatory synaptic transmission and changes in their numbers and morphology have been associated with neurodevelopmental and neurodegenerative disorders. Brain-derived Neurotrophic Factor (BDNF) is a secreted growth factor that influences hippocampal, striatal and neocortical pyramidal neuron dendritic spine density. However, the mechanisms by which BDNF regulates dendritic spines and how BDNF interacts with other regulators of spines remain unclear. We propose that one mechanism by which BDNF promotes dendritic spine formation is through an interaction with Wnt signaling. Here, we show that Wnt signaling inhibition in cultured cortical neurons disrupts dendritic spine development, reduces dendritic arbor size and complexity, and blocks BDNF-induced dendritic spine formation and maturation. Additionally, we show that BDNF regulates expression of Wnt2, and that Wnt2 is sufficient to promote cortical dendrite growth and dendritic spine formation. Together, these data suggest that BDNF and Wnt signaling cooperatively regulate dendritic spine formation
Freshwater diatom persistence on clothing II: Further analysis of species assemblage dynamics over investigative timescales
Diatoms are a useful form of environmental trace evidence, yielding a circumstantial link between persons and scenes of forensic interest. A developing empirical research base has sought to understand those factors affecting the transfer and persistence of freshwater diatoms on clothing and footwear surfaces. Although an initial study has demonstrated that diatoms can persist on clothing following weeks of wear, no previous research has explored the temporal dynamics of a persistent species assemblage over timescales pertinent to forensic investigations. This study therefore aimed to determine if: (1) valve morphology (size and shape) influences diatom persistence, (2) the relative abundance of taxa within an assemblage affects retention, and (3) a persistent diatom assemblage retrieved from clothing after one month can reliably be compared to the site of initial transfer. To build on previous research findings which highlighted the impact of substrate and environmental seasonality on diatom transfer and persistence, here, nine clothing materials were tested in spring before a seasonal comparison in the winter. Fabric swatches were immersed in a freshwater river, worn attached to clothing, and subsamples retrieved at regular intervals (hours, days, weeks) up to one month post-immersion. Diatoms were extracted using a H2O2 technique and analysed via microscopy. The results indicated that smaller diatoms (< 10 Āµm) are retained in significantly greater abundance, with no statistically significant difference between centric and pennate diatom loss over time. Although a persistent species assemblage was relatively stable over the one month of wear, significant differences were identified between clothing substrate in the spring and between the seasonal samples. The most abundant environmental taxa were consistently identified in the forensic samples, with greater variability attributed to the retention of relatively less common species. The findings suggest that, despite a loss in the abundance and species-richness of diatoms retrieved from clothing over time, a persistent assemblage may provide a useful circumstantial link to the site of initial transfer. The complex relationships between clothing type, environmental seasonality, and time since wear on retention, emphasise the need for diatom trace evidence to be carefully interpreted within an exclusionary framework, and the significance of any casework findings to be determined with reference to empirical evidence bases
Freshwater diatom persistence on clothing I: A quantitative assessment of trace evidence dynamics over time
Freshwater diatoms offer valuable circumstantial forensic indicators, with a growing empirical research base aiming to identify and understand some of the spatial and temporal factors affecting their validity as trace evidence. Previous studies demonstrated that recipient surface characteristics, environmental variability, and individual species traits influence the initial transfer of freshwater diatoms to clothing. However, no previous research has sought to consider the impact of these and other variables on the persistence of transferred diatoms over investigative timescales. Therefore, this study aimed to identify and explore diatom retention dynamics on clothing following wear over time (hours to weeks). A series of experiments were designed to examine the impact of clothing material, seasonality, and time since wear (persistence interval) on the total number and species-richness of diatoms recovered and their relative retention (%) over time. Nine clothing swatches were immersed in a freshwater environment and then worn for one month in the spring. Subsamples were retrieved at regular intervals (e.g. 30Ā mins, 1Ā h, 8Ā h, 24Ā h) up to one month, diatoms were extracted using a H2O2 method, and examined microscopically. Three clothing materials were subject to the same experiment in the winter to generate a seasonal comparison. The results broadly identified three stages of diatom persistence on clothing - rapid initial loss, variable intermediate decay, and sustained long-term presence. Clothing material significantly impacted the number of diatoms recovered and retention dynamics over time, with complex interactions identified with seasonality. Although fewer diatoms were recovered in the winter, overall retention trends were consistent at the different times of year. The findings demonstrate that diatoms can be recovered from clothing, even weeks or months after an initial transfer, yielding a useful environmental trace indicator for forensic reconstructions over investigative timescales. The impact of clothing material and seasonality on persistence identified cotton, acrylic, and viscose clothing as the most reliable temporal repository of diatom trace evidence, with a more abundant forensic assemblage available for forensic comparisons in the spring
Home based exercise programme for knee pain and knee osteoarthritis: randomised controlled trial
Objectives To determine whether a home based
exercise programme can improve outcomes in
patients with knee pain.
Design Pragmatic, factorial randomised controlled
trial of two years' duration.
Setting Two general practices in Nottingham.
Participants 786 men and women aged >45 years
with self reported knee pain.
Interventions Participants were randomised to four
groups to receive exercise therapy, monthly telephone
contact, exercise therapy plus telephone contact, or no
intervention. Patients in the no intervention and
combined exercise and telephone groups were
randomised to receive or not receive a placebo health
food tablet.
Main outcome measures Primary outcome was self
reported score for knee pain on the Western Ontario
and McMaster universities (WOMAC) osteoarthritis
index at two years. Secondary outcomes included
knee specific physical function and stiffness (scored on
WOMAC index), general physical function (scored on
SFĀ36 questionnaire), psychological outlook (scored
on hospital anxiety and depression scale), and
isometric muscle strength.
Results 600 (76.3%) participants completed the study.
At 24 months, highly significant reductions in knee
pain were apparent for the pooled exercise groups
compared with the nonĀexercise groups (mean
difference ā0.82, 95% confidence interval ā1.3 to
ā0.3). Similar improvements were observed at 6, 12,
and 18 months. Regular telephone contact alone did
not reduce pain. The reduction in pain was greater
the closer patients adhered to the exercise plan.
Conclusions A simple home based exercise
programme can significantly reduce knee pain. The
lack of improvement in patients who received only
telephone contact suggests that improvements are not
just due to psychosocial effects because of contact
with the therapist
Navigating new sexual partnerships in midlife: a socioecological perspective on factors shaping STI risk perceptions and practices
OBJECTIVE: Despite increases in STIs among those over 40, little is known about the social context of STI transmission among people experiencing relationship transition in midlife, and few sexual health promotion initiatives are targeted at this group. This study sought to identify factors shaping STI risk perceptions and practices among midlife individuals either contemplating or having sex with new partners following the end of a long-term relationship. METHODS: Participants were purposively selected from respondents to Britain's third National Survey of Sexual Attitudes and Lifestyles, using three eligibility criteria: aged 40-59, reported experience of the end of a marital or cohabiting relationship with an opposite-sex partner in the past 5āyears, and willingness to participate in a qualitative interview. Qualitative data were generated via face-to-face interviews with 10 women and 9 men and analysed inductively using thematic analysis, with themes then organised using a socioecological framework. RESULTS: Participants' accounts of new sexual partnerships in midlife indicate that STI risk perceptions and practices are shaped by factors operating at multiple levels across the socioecological arena (individual, partnership, peers and communities, societal). Constraints on, and resources for, the navigation of sexual safety include self-perceived STI risk rooted in past rather than present circumstances; legacies of mistrust within former relationships; intersecting gender-age dynamics in negotiation of risk prevention strategies with new partners; peers and younger relatives' influences on understandings of sexual risk and safety; postrelationship change in social networks that increase or mitigate vulnerability to sexual risk; age-related barriers to accessing condoms; and disconnection from safer sex messaging and services culturally coded as for the young. CONCLUSIONS: Improving sexual health among midlife adults requires age-sensitive interventions designed to address multilevel constraints, and harness positive influences, on the navigation of sexual safety at this stage of life
Fortification of grain foods and NOVA: the potential for altered nutrient intakes while avoiding ultra-processed foods
Purpose: NOVA is a food classification system describing a hierarchy from minimally processed to ultra-processed foods (UPF). Research has associated intake of UPF with chronic diseases. In Australia, the primary sources of grains, both refined and whole, are breads and breakfast cereals, which are typically fortified. Most are classified as UPF, yet are recommended core foods according to the Australian Dietary Guidelines (ADG). This research aimed to identify if avoidance of ultra-processed grain foods would alter nutrient intakes in an Australian population and whether sample diets using substitute (non-UPF) foods would be likely to meet nutrient requirements. Methods: Quantitative analysis of usual nutrient intake from the National Nutrition and Physical Activity Survey 2011ā12 (n = 12,153) for all foods including and excluding UPF. Dietary modelling examined the nutritional adequacy of sample diets aligned with the ADG and another containing replacements for UPF. We particularly focused on grain foods and meeting whole-grain intake targets. Results: There was a significant decrease (all p < 0.05) in modelled intake of key nutrients when UPF were excluded, specifically, thiamin, folate and iodine, as substitutions are rarely fortified. Diets with no UPF, where substitutes are carefully chosen, have the potential to meet Nutrient Reference Values, but deviation from customary food choices may mean adoption of substitutes is unlikely. Conclusions: Exclusion of UPF may result in lowered intakes of key nutrients of particular concern for at risk groups (including women of child-bearing age), negating gains made by public health policy of fortification. Substitutions may not be realistic in these at-risk populations
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