Examining the Impact of Mercury on Waterfowl with Implications for Human Health and Water Management in Arid Environments

The work described in this thesis provides detailed insight into total mercury concentrations ([tHg]) observed in wood ducks along the lower Carson River watershed in western Nevada. Mercury (Hg) contamination of the Carson River dates back to the Comstock era mines in the late 1800’s, where Hg amalgamation methods were used to extract silver and gold from ore deposits. Wood ducks frequently use this river system, and thus may be impacted by the Hg contamination in the system. Mercury is of concern due to the impacts that it has on wildlife and humans; these include neurotoxicity, decreased reproductive success, and physiological and behavioral effects. The objectives for this thesis were to develop a predictive function that could be used to estimate internal waterfowl tissue [tHg] using feather [tHg], and examine the impact of several covariates (i.e., age class, site location, year) and environmental samples on Hg in wood ducks on the Carson River. Feathers were used from an archived data set and tissues obtained in 2020 and 2021 from harvested specimens donated by local hunters. Mercury concentrations ([Hg]) in water, sediment, macroinvertebrates, and terrestrial and aquatic vegetation samples were collected in 2020 and 2021 to assess sources of Hg to wood ducks. Hunter donated samples were used to examine correlations in [Hg] among tissues (feathers, breast and liver tissue) to explore potential nonlethal waterfowl sampling techniques to estimate Hg exposure to hunters. A contemporary Bayesian hierarchical model was used to estimate relationships between feathers and internal tissue [Hg]. A prediction function was developed that allowed for estimation of internal tissue [Hg] using flank feather [Hg]. This model was tested using harvested mallards from Stillwater National Wildlife Refuge. A Bayesian analysis of [Hg] in wood duck data, using archived flank feather samples collected from 2010–2019, was conducted to characterize trends of Hg in this population. Over time, hens (adult females with nests) consistently had lower feather [Hg] than offspring (hatch years observed hatching or in a brood). There was a large increase in feather [Hg] in higher water flow years. Environmental samples collected from 5 field sites, extending from the U.S. Geological Service (USGS) gauge at the Carson River below Lahontan Reservoir to the USGS gauge at Tarzyn Road, demonstrated no spatial trends in [Hg] among sites. However, there were clear temporal trends. As water flows increased between sampling occasions, increases in water and duckweed [Hg] were observed. Based on observed [Hg] measurements, important vectors of Hg to wood ducks occur through duckweed consumption and exposure to contaminated waters. Mercury concentrations in wood duck tissues indicate a consumption advisory is warranted

“It still haunts me whether we did the right thing”: a qualitative analysis of free text survey data on the bereavement experiences and support needs of family caregivers

Background Research suggests that there may be bereavement experiences and support needs which are specific to family caregivers providing end of life care (EoLC), although this remains an under-researched area. This paper focuses on themes relating to bereavement which were derived from an analysis of free text survey responses collected in a research priority setting exercise for palliative and EoLC. Methods The priority setting exercise involved a public survey, designed to generate research priorities. Rather than identify research topics, many people instead described their experiences and raised more general questions relating to palliative and end of life care. To explore these experiences and perspectives a supplementary thematic analysis was conducted on the survey responses. 1403 respondents took part, including patients, current and bereaved carers, health and social care professionals, volunteers and members of the public. Results Several grief issues were identified, which seem specific to the experiences of family caregivers. Responses demonstrated a relationship between death experiences, feelings of guilt and bereavement outcomes for some family caregivers, as well as caregiver experiences of a “void” created by the withdrawal of professional support after death. Communication and support needs were also identified by participants. Conclusion This analysis provides further evidence of some of the specific effects that caring for a loved one at the end of life can have on bereavement experiences. Finding ways of improving communication around the time of death and effective follow up approaches post death could help to address some of these issues

Integration of speech and gesture in aphasia

BACKGROUND: Information from speech and gesture is often integrated to comprehend a message. This integration process requires the appropriate allocation of cognitive resources to both the gesture and speech modalities. People with aphasia are likely to find integration of gesture and speech difficult. This is due to a reduction in cognitive resources, a difficulty with resource allocation or a combination of the two. Despite it being likely that people who have aphasia will have difficulty with integration, empirical evidence describing this difficulty is limited. Such a difficulty was found in a single case study by Cocks et al. in 2009, and is replicated here with a greater number of participants. AIMS: To determine whether individuals with aphasia have difficulties understanding messages in which they have to integrate speech and gesture. METHODS & PROCEDURES: Thirty-one participants with aphasia (PWA) and 30 control participants watched videos of an actor communicating a message in three different conditions: verbal only, gesture only, and verbal and gesture message combined. The message related to an action in which the name of the action (e.g., 'eat') was provided verbally and the manner of the action (e.g., hands in a position as though eating a burger) was provided gesturally. Participants then selected a picture that 'best matched' the message conveyed from a choice of four pictures which represented a gesture match only (G match), a verbal match only (V match), an integrated verbal-gesture match (Target) and an unrelated foil (UR). To determine the gain that participants obtained from integrating gesture and speech, a measure of multimodal gain (MMG) was calculated. OUTCOMES & RESULTS: The PWA were less able to integrate gesture and speech than the control participants and had significantly lower MMG scores. When the PWA had difficulty integrating, they more frequently selected the verbal match. CONCLUSIONS & IMPLICATIONS: The findings suggest that people with aphasia can have difficulty integrating speech and gesture in order to obtain meaning. Therefore, when encouraging communication partners to use gesture alongside language when communicating with people with aphasia, education regarding the types of gestures that would facilitate understanding is recommended

Time varying Na I D absorption in ILRTs as a probe of circumstellar material

Intermediate-Luminosity Red Transients (ILRTs) are a class of observed transient posited to arise from the production of an electron-capture supernova from a super-asymptotic giant branch star within a dusty cocoon. In this paper, we present a systematic analysis of narrow Na I D absorption as a means of probing the circumstellar environment of these events. We find a wide diversity of evolution in ILRTs in terms of line strength, time-scale, and shape. We present a simple toy model designed to predict this evolution as arising from ejecta from a central supernova passing through a circumstellar environment wherein Na II is recombining to Na I over time. We find that while our toy model can qualitatively explain the evolution of a number of ILRTs, the majority of our sample undergoes evolution more complex than predicted. The success of using the Na I D doublet as a diagnostic tool for studying circumstellar material will rely on the availability of regular high-resolution spectral observations of multiple ILRTs, and more detailed spectral modelling will be required to produce models capable of explaining the diverse range of behaviours exhibited by ILRTs. In addition, the strength of the Na I D absorption feature has been used as a means of estimating the extinction of sources, and we suggest that the variability visible in ILRTs would prevent such methods from being used for this class of transient, and any others showing evidence of variabilityComment: 14 pages, 10 figures, submitted to MNRA

Real-time sweat pH monitoring based on a wearable chemical barcode micro-fluidic platform incorporating ionic liquids

This work presents the fabrication, characterisation and the performance of a wearable, robust, flexible and disposable chemical barcode device based on a micro-fluidic platform that incorporates ionic liquid polymer gels (ionogels). The device has been applied to the monitoring of the pH of sweat in real time during an exercise period. The device is an ideal wearable sensor for measuring the pH of sweat since it does not contents any electronic part for fluidic handle or pH detection and because it can be directly incorporated into clothing, head- or wristbands, which are in continuous contact with the skin. In addition, due to the micro-fluidic structure, fresh sweat is continuously passing through the sensing area providing the capability to perform continuous real time analysis. The approach presented here ensures immediate feedback regarding sweat composition. Sweat analysis is attractive for monitoring purposes as it can provide physiological information directly relevant to the health and performance of the wearer without the need for an invasive sampling approac

Automatic Detection and Tracking of Coronal Mass Ejections. II. Multiscale Filtering of Coronagraph Images

Studying CMEs in coronagraph data can be challenging due to their diffuse structure and transient nature, and user-specific biases may be introduced through visual inspection of the images. The large amount of data available from the SOHO, STEREO, and future coronagraph missions, also makes manual cataloguing of CMEs tedious, and so a robust method of detection and analysis is required. This has led to the development of automated CME detection and cata- loguing packages such as CACTus, SEEDS and ARTEMIS. Here we present the development of a new CORIMP (coronal image processing) CME detection and tracking technique that overcomes many of the drawbacks of current catalogues. It works by first employing the dynamic CME separation technique outlined in a companion paper, and then characterising CME structure via a multiscale edge-detection algorithm. The detections are chained through time to determine the CME kinematics and morphological changes as it propagates across the plane-of-sky. The effectiveness of the method is demonstrated by its application to a selection of SOHO/LASCO and STEREO/SECCHI images, as well as to synthetic coronagraph images created from a model corona with a variety of CMEs. The algorithms described in this article are being applied to the whole LASCO and SECCHI datasets, and a catalogue of results will soon be available to the public.Comment: 18 pages, 10 figure

Improving Rural Bone Health and Minimizing Fracture Risk in West Virginia: Validation of the World Health Organization FRAX® Assessment Tool as a Phone Survey for Osteoporosis Detection

West Virginia ranks second nationally in population ≥ 65 years old placing our state at greater risk for osteoporosis and fracture. The gold standard for detecting osteoporosis is dual X-ray absorptiometry (DXA), yet over half of West Virginia’s counties do not have this machine. Due to access barriers, a validated phone-administered fracture prediction tool would be beneficial for osteoporosis screening. The World Health Organization’s FRAX® fracture prediction tool was administered as a phone survey to 45 patients; these results were compared to DXA bone mineral density determination. Results confirmed that the FRAX® phone survey is as reliable as DXA in detecting osteoporosis or clinically significant osteopenia: 92% positive predictive value, 100% negative predictive value, 100% sensitivity and 91% specificity when compared to the gold standard. These promising results allow for the development of telephone-based protocols to improve osteoporosis detection, referral and treatment especially in areas with health care access barriers

Children's creative collaboration during a computer-based music task

The purpose of this study was to identify and analyse specific instances of transactive communication as children engaged in a paired melody writing task using a computer-based composing environment. Transactive communication has been identified as one of the features of general collaborative engagement that is most helpful in an educational sense, and which makes collaborative learning an important tool for learning and teaching. The paper reports the results of an empirical study in which a group of 10 and 11 year olds worked in pairs to compose short melodies using computers. Analysis of between-pupil dialogue suggested that levels of transactive communication varied between pairs, and also within pairs as pupils took on different roles at the computer. Factors of individual difference, such as musical expertise or whether the pair were friends, did not appear to have a significant influence on the extent of, or nature or, transactive communication