Nilesh Timilsina measuring tree height in a mangrove forest impacted by Hurricane Wilma, Harney River

This material is based upon work supported by the National Science Foundation through the Florida Coastal Everglades Long-Term Ecological Research program under Cooperative Agreements #DBI-0620409 and #DEB-9910514. This image is made available for non-commercial or educational use only.

Understanding arsenic mobility and speciation in lake sediments impacted by ore roasting near Giant mine, NWT

The roasting of gold-bearing arsenopyrite at Giant mine (Northwest Territories) between 1949 and 1999 released approximately 20,000 tonnes of toxic arsenic-bearing aerosols in the local aerial environment. Detailed examination of lake sediments, sediment porewaters, surface waters and lake hydrology sampled from three lakes of differing limnological characteristics was conducted in summer and winter conditions. Samples were analyzed for solid and dissolved elemental concentrations, speciation and mineralogy. The three lakes are located less than 5km from the mine roaster, and downwind, based on predominant wind direction. The objective of the study was to assess the controls on the mobility and fate of arsenic in these roaster-impacted subarctic lacustrine environments. Results show that the occurrence of arsenic trioxide in lake sediments coincides with the regional onset of industrial activities. The bulk of arsenic in sediments is contained in the form of secondary sulphide precipitates, with iron oxides hosting a minimal amount of arsenic near the surface-water interface. The presence of geogenic arsenic is likely contained as dilute impurities in common rock-forming minerals, and is not believed to be a significant source of arsenic to sediments, porewaters or lake waters. Furthermore, the well correlated depth-profiles of arsenic, antimony and gold in sediments may help reveal roaster impact. The soluble arsenic trioxide particles contained in sediments act as the primary source of arsenic into porewaters. Dissolved arsenic in reducing porewaters both precipitate as secondary sulphides in situ, and diffuse upwards into the overlying lake waters. Arsenic diffusion out of porewaters, combined with watercourse-driven residence time, are estimated to be the predominant mechanisms controlling arsenic concentrations in overlying lake waters. The sequestration of arsenic from porewaters as sulphide precipitates, in the study lakes, is not an effective process in keeping lake-water arsenic concentrations below guidelines for the protection of the freshwater environment and drinking water. Seasonal impacts on lake geochemistry derive from ice covering lake waters, cutting them off from of atmospheric oxygen, along with the exclusion of solutes from the ice. Such effects are limited in deep lakes but are can be an important factor controlling arsenic precipitation and mobility in ponds.

Tooth replacement for partially dentate elders: a willingness-to-pay analysis

Objectives: The primary aim of this study was to investigate partially dentate elders' willingness-to-pay (WTP) for two different tooth replacement strategies: Removable Partial Dentures (RPDs) and, functionally orientated treatment according to the principles of the Shortened Dental Arch (SDA). The secondary aim was to measure the same patient groups' WTP for dental implant treatment.Methods: 55 patients who had completed a previous RCT comparing two tooth replacement strategies (RPDs (n=27) and SDA (n=28)) were recruited (Trial Registration no. ISRCTN26302774). Patients were asked to indicate their WTP for treatment to replace missing teeth in a number of hypothetical scenarios using the payment card method of contingency evaluation coupled to different costs. Data were collected on patients' social class, income levels and other social circumstances. A Mann-Whitney U Test was used to compare differences in WTP between the two treatment groups. To investigate predictive factors for WTP, multiple linear regression analyses were conducted.Results: The median age for the patient sample was 72.0 years (IQR: 71-75 years). Patients who had been provided with RPDs indicated that their WTP for this treatment strategy was significantly higher (€550; IQR: 500-650) than those patients who had received SDA treatment (€500; IQR: 450-550) (p=0.003). However patients provided with RPDs indicated that their WTP for SDA treatment (€650; IQR: 600-650) was also significantly higher than those patients who had actually received functionally orientated treatment (€550; IQR: 500-600) (p<0.001). The results indicated that both current income levels and previous treatment allocation were significantly correlated to WTP for both the RPD and the SDA groups. Patients in both treatment groups exhibited little WTP for dental implant treatment with a median value recorded which was half the market value for this treatment (€1000; IQR: 500-1000).Conclusions: Amongst this patient cohort previous treatment experience had a strong influence on WTP as did current income levels. Both treatment groups indicated a very strong WTP for simpler, functionally orientated care using adhesive fixed prostheses (SDA) over conventional RPDs. Clinical significance: Partially dentate older patients expressed a strong preference for functionally orientated tooth replacement as an alternative to conventional RPDs.

Contribución del estudio neurofisiológico al diagnóstico y control evolutivo de la enfermedad de Charcot-Marie-Tooth en la provincia de Las Palmas

Programa de doctorado: Patología Quirúrgica

Macroinvertebrate communities and habitat structure in least-impacted hill streams of central Portugal

We surveyed macroinvertebrate communities in 31 hill streams in the Vouga River and Mondego River catchments in central Portugal. Despite applying a "least-impacted" criterion, channel and bank management was common, with 38% of streams demonstrating channel modification (damming) and 80% with evidence of bank modification. Principal component analysis (PCA) at the family and species level related the macroinvertebrates to habitat variables derived at three spatial scales -- site (20 m), reach (200 m), and catchment. Variation in community structure between sites was similar at the species and family level and was statistically related to pH, conductivity, temperature, flow, shade, and substrate size at the site scale; channel and bank habitat and riparian vegetation and land-use at the reach scale; and altitude and slope at the catchment scale. While the effects of river management were apparent in various ecologically important habitat features at the site and reach scale, a direct relationship with macroinvertebrate assemblages was only apparent between the extent of walled banks and the secondary PCA axis described by species data. The strong relationship between catchment scale variables and descriptors of physical structure at the reach and site scale suggests that catchment-scale parameters are valuable predicators of macroinvertebrate community structure in these streams despite the anthropogenic modifications of the natural habitat.

Effectiveness of tooth wipes in removing babies' dental biofilm

PURPOSE To assess the effectiveness of tooth wipes in removing dental biofilm from babies' anterior teeth, as well as to evaluate the babies' behaviour and the guardians' preference concerning hygiene methods. MATERIALS AND METHODS In this random blind cross-over study, 50 high caries risk babies, from 8 to 15 months old, were divided into two groups: babies with oral hygiene performed by caregivers (n = 25) or by their mothers (n = 25). The caregivers and mothers removed biofilm using three methods of oral hygiene (tooth wipes, toothbrushes and gauze), one in each experimental phase. Professional cleaning was done before each phase, which had 2 days of biofilm accumulation and 1 experimental day, when caregivers and mothers used one method to remove biofilm. Examiners blinded to the study design assessed the biofilm index at baseline, prior to and following biofilm removal using each method. The babies' behaviour and the mothers'/caregivers' preference were assessed. RESULTS The tooth wipes, toothbrushes and gauze significantly reduced the amount of biofilm (P < 0.001). The mothers' group removed more biofilm than the caregivers' group, using toothbrushes or tooth wipes (P < 0.05). Babies in the mothers' group had better behaviour using tooth wipes than toothbrushes (P < 0.05). Mothers and caregivers preferred to use tooth wipes. CONCLUSIONS Tooth wipes are effective in removing biofilm from babies' anterior teeth and are the method best accepted by mothers, caregivers and babies.

Tooth Mobility, Periodontal Ligament Space, and the Alveolus During Periodontal Health, Disease, and Disuse

Thesis (Ph.D.)--University of Washington, 2016-07

How Have Institutional Barriers Impacted Implementation of Ecosystem Based Fishery Management in the US

Thesis (Master's)--University of Washington, 2016-08

Impact of hypomineralized teeth and sociobehavioral aspects on caries development: a prospective cohort study

Aim: This prospective cohort study was to evaluate the independent and mutual effects of socioeconomic, oral health behaviors and individual clinical factors, including enamel hypomineralization, as possible risk factors for increase in caries experience in second primary molar (SPM) over a period of 2-years. Methods: Children (n=216) aged 4-6 years were examined for hypomineralized second primary molar (HSPM) and dental caries in school settings and were recalled every 6 months. The caregivers filled out a semi-structured questionnaire about their socio-demographic and oral health-related behaviors. Data analysis was performed using a hierarchical model with three levels. Multiple analyses were performed at each level and variables with p<0.20 were tested by stepwise multiple Generalized Estimating Equation. Results: At final examination, 33.3% of the children had developed new caries lesions in SPM. The model showed that the number of years of mother’s schooling and the caregiver´s perception about their children’s caries experience played a protective role in the incidence of dental caries. Children who had white spot lesions were more likely to develop new carious lesions in SPM. Children with HSPM showed no higher incidence of caries in their SPM than those without HSPM. Conclusions: Clinical, socioeconomic and behavioral factors impacted on caries development in primary second molars. However, further studies are required to better understand the role of HSPM in caries development in other age groups.

Charcot Marie Tooth disease (CMT4A) due to GDAP1 mutation: report of a colombian family

Background: Mutations of GDAP1 gene cause autosomal dominant and autosomal recessive Charcot-Marie-Tooth disease and more than 40 different mutations have been reported. The recessive Q163X mutation has been described in patients of Spanish ancestry, and a founder mutation in South American patients, originating in Spain has been demonstrated. Objective: We describe physical and histological features, and the molecular impact of mutation Q163X in a Colombian family. Methods: We report two female patients, daughters of consanguineous parents, with onset of symptoms within the first two years of life, developing severe functional impairment, without evidence of dysmorphic features, hoarseness or diaphragmatic paralysis. Electrophysiology tests showed a sensory and motor neuropathy with axonal pattern. Sequencing of GDAP1 gene was requested and the study identified a homozygous point mutation (c.487 C>T) in exon 4, resulting in a premature stop codon (p.Q163X). This result confirms the diagnosis of Charcot-Marie-Tooth disease, type 4A. Results: The patients were referred to Physical Medicine and Rehabilitation service, in order to be evaluated for ambulation assistance. They have been followed by Pulmonology service, for pulmonary function assessment and diaphragmatic paralysis evaluation. Genetic counseling was offered. The study of the genealogy of the patient, phenotypic features, and electrophysiological findings must be included as valuable tools in the clinical approach of the patient with Charcot-Marie-Tooth disease, in order to define a causative mutation. In patients of South American origin, the presence of GDAP1 gene mutations should be considered, especially the Q163X mutation, as the cause of CMT4A disease.

Charcot Marie Tooth disease (CMT4A) due to GDAP1 mutation: report of a colombian family

Background: Mutations of GDAP1 gene cause autosomal dominant and autosomal recessive Charcot-Marie-Tooth disease and more than 40 different mutations have been reported. The recessive Q163X mutation has been described in patients of Spanish ancestry, and a founder mutation in South American patients, originating in Spain has been demonstrated. Objective: we describe physical and histological features, and the molecular impact of mutation Q163X in a Colombian family. Methods: We report two female patients, daughters of consanguineous parents, with onset of symptoms within the first two years of life, developing severe functional impairment, without evidence of dysmorphic features, hoarseness or diaphragmatic paralysis. Electrophysiology tests showed a sensory and motor neuropathy with axonal pattern. Sequencing of GDAP1 gene was requested and the study identified a homozygous point mutation (c.487 C>T) in exon 4, resulting in a premature stop codon (p.Q163X). This result confirms the diagnosis of Charcot-Marie-Tooth disease, type 4A. Results: The patients were referred to Physical Medicine and Rehabilitation service, in order to be evaluated for ambulation assistance. They have been followed by Pulmonology service, for pulmonary function assessment and diaphragmatic paralysis evaluation. Genetic counseling was offered. The study of the genealogy of the patient, phenotypic features, and electrophysiological findings must be included as valuable tools in the clinical approach of the patient with Charcot-Marie-Tooth disease, in order to define a causative mutation. In patients of South American origin, the presence of GDAP1 gene mutations should be considered, especially the Q163X mutation, as the cause of CMT4A disease.

Geographic Variation of Notified Ross River Virus Infections in Queensland, Australia, 1985-1996

The spatial and temporal variations of Ross River virus infections reported in Queensland, Australia, between 1985 and 1996 were studied by using the Geographic Information System. The notified cases of Ross River virus infection came from 489 localities between 1985 and 1988, 805 between 1989 and 1992, and 1,157 between 1993 and 1996 (chi2(df = 2) = 680.9; P < 0.001). There was a marked increase in the number of localities where the cases were reported by 65 percent for the period of 1989-1992 and 137 percent for 1993-1996, compared with that for 1985-1988. The geographic distribution of the notified Ross River virus cases has expanded in Queensland over recent years. As Ross River virus disease has impacted considerably on tourism and industry, as well as on residents of affected areas, more research is required to explore the causes of the geographic expansion of the notified Ross River virus infections.

Diversity of accuracy profiles for absolute pitch recognition

Most advanced musicians are able to identify and label a heard pitch if given an opportunity to compare it to a known reference note. This is called ‘relative pitch’ (RP). A much rarer skill is the ability to identify and label a heard pitch without the need for a reference. This is colloquially referred to as ‘perfect pitch’, but appears in the academic literature as ‘absolute pitch’ (AP). AP is considered by many as a remarkable skill. As people do not seem able to develop it intentionally, it is generally regarded as innate. It is often seen as a unitary skill and that a set of identifiable criteria can distinguish those who possess the skill from those who do not. However, few studies have interrogated these notions. The present study developed and applied an interactive computer program to map pitch-labelling responses to various tonal stimuli without a known reference tone available to participants. This approach enabled the identification of the elements of sound that impacted on AP. Pitch-labelling responses of 14 participants with AP were recorded for their accuracy. Each participant’s response to the stimuli was unique. Their accuracy of labelling varied across dimensions such as timbre, range and tonality. The diversity of performance between individuals appeared to reflect their personal musical experience histories.