28232 research outputs found
Sort by
Duke Digital Repository usability test, part 2 - May 2023
No full textThis is part two out of two usability tests of the Duke Digital Repositories (DDR). Both parts were designed to answer stakeholder questions about the usability of specific DDR functions. All test sessions were conducted remotely via Zoom by Audrey Siqi-Liu. Part one included basic tasks like downloading digital materials and requesting access to metadata only items.
Part two included more advanced tasks: navigating finding aids and collection records, and using the relations feature. Participants were recruited from users of the DDR who had logged in for the first time over the past six months and were prescreened for either experience with browsing digital collections or using any reading room
Communication: Weakening the critical dynamical slowing down of models with SALR interactions.
No full textIn systems with frustration, the critical slowing down of the dynamics severely impedes the numerical study of phase transitions for even the simplest of lattice models. In order to help sidestep the gelation-like sluggishness, a clearer understanding of the underlying physics is needed. Here, we first obtain generic insight into that phenomenon by studying one-dimensional and Bethe lattice versions of a schematic frustrated model, the axial next-nearest neighbor Ising (ANNNI) model. Based on these findings, we formulate two cluster algorithms that speed up the simulations of the ANNNI model on a 2D square lattice. Although these schemes do not eliminate the critical slowing own, speed-ups of factors up to 40 are achieved in some regimes
Correction to: The Society for Implementation Research Collaboration Instrument Review Project: a methodology to promote rigorous evaluation.
No full textFollowing publication of the original article [1] the authors reported an important acknowledgement was mistakenly omitted from the 'Acknowledgements' section. The full acknowledgement is included in this Correction article
Winding number of a Brownian particle on a ring under stochastic resetting
No full textAbstract
We consider a random walker on a ring, subjected to resetting at Poisson-distributed times to the initial position (the walker takes the shortest path along the ring to the initial position at resetting times). In the case of a Brownian random walker the mean first-completion time of a turn is expressed in closed form as a function of the resetting rate. The value is shorter than in the ordinary process if the resetting rate is low enough. Moreover, the mean first-completion time of a turn can be minimised in the resetting rate. At large time the distribution of winding numbers does not reach a steady state, which is in contrast with the non-compact case of a Brownian particle under resetting on the real line. The mean total number of turns and the variance of the net number of turns grow linearly with time, with a proportionality constant equal to the inverse of the mean first-completion time of a turn.</jats:p
Health System Capacity for Epilepsy Care in Uganda: A Survey of Health Facilities In Western Uganda
No full textBackgroundEpilepsy is a chronic neurological disorder characterized by recurrent seizure activity caused by abnormal electrical activity in the brain. Over 80% of all cases globally occur in Low- and Middle-Income countries. A high treatment gap exists in LMICs, including Uganda, with 80% of people with epilepsy never receiving treatment. Studies have shown that even with existing medical services, a lack of skilled workforce, medication stock-outs, and long distances to health facilities contribute to the high treatment gap. This study describes the capacity, distribution of health facilities, and referral patterns between facilities that care for epilepsy patients in Uganda. MethodsWe conducted a cross-sectional survey adapted from the WHO Tool for Situational Analysis to Assess Emergency and Essential Surgical Care. It was modified to include WHO Mental Health Gap Action Program (mhGAP) resources for epilepsy and the Tool for Situational Analysis to Assess Epilepsy Care. Data collection occurred between July and August 2022. Our sample included all regional and general hospitals and a sample of randomly selected Health Centers in Southwestern Uganda. We used probability proportional to size sampling to determine which Health Centers to include in our sample.
We had only public health facilities in our sample. Data were collected through in-person interviews conducted by trained research assistants. A three-tiered categorical score (full, intermediate, and low capacity) was used to describe epilepsy capacity. For scoring, hospitals were stratified into three groups/facility levels: tertiary care (regional referral hospitals), secondary care (district hospitals/health center IVs), and primary care (health center IIIs), as we hypothesized that available resources would differ between the groups. We did geospatial mapping to show the distribution of facilities.Ethical approval was obtained from the Makerere School of Public Health Research Ethics Committee (Protocol 1104), the Uganda National Council of Science and Technology (Protocol HS2344ES), and Duke University’s Institutional Review Board (Protocol 00110747).Results63 facilities were surveyed, with 100% completion in all facilities. 63 (100%) facilities provide care for epilepsy patients. None of the facilities surveyed had full capacity to treat epilepsy patients. Most of our sampled facilities had a low capacity to treat epilepsy: 100% of tertiary care facilities, 77.3% of secondary care facilities, and 83.8% of primary care facilities. Overall capacity was weakest in medication, equipment, and human resources and highest in infrastructure and guidelines.
Conclusion
While epilepsy services are present in Uganda’s southwestern region, a lack of vital medicines, staff shortages, and technology can limit service delivery. Task shifting and sharing have been widely implemented to address workforce shortages. The findings of this study can help inform policy to improve service delivery for epilepsy patients.</p
SEVERAL TOPICS SURROUNDING HARMFUL ALGAL BLOOMS ON THE US WEST COAST
No full textHarmful Algal Blooms are not new to the West Coast region, but changing ocean conditions are increasing the frequency of Harmful Algal Bloom events. This Masters Project is split into three separate projects, each examining a topic surrounding Harmful Algal Blooms on the West Coast. The first project examines the two policy options for receiving disaster assistance to mitigate the impacts of Harmful Algal Blooms. Communities impacted by a Harmful Algal Bloom may request NOAA for one of two disaster determinations: 1) a Fishery Disaster determination or 2) a Harmful Algal Bloom or Hypoxia Event of National Significance (HHENS) determination. I conducted a policy analysis that maps the criteria used in NOAA’s determinations to the “Attributes” in the 4Cs Human Well-being Framework. Fishery Disaster determinations are mainly concerned with the economic impacts of a Harmful Algal Bloom on the commercial fishery. HHENS determinations, a relatively new policy option, considers a wider range of impacts on commercial, recreational, and subsistence communities. The second project examines two resilience strategies that utilize disaster assistance to mitigate Harmful Algal Bloom impacts: 1) Direct Assistance to impacted fishers and processors and 2) Investment in Infrastructure and Knowledge Production. I wrote a Strategy Narrative describing strategy outcomes based on the first project’s policy review and scientific literature surrounding the 2015 HAB event. The first strategy narrative describes how Direct Assistance increases financial security and decreases the financial-related stress of impacted fishers. The second strategy describes how Investment in Infrastructure and Knowledge Production increases the knowledge and technological capacity of the fishing community. The third project is an independent project that uses ArcGIS Pro and Python to identify Algal Bloom hotspots off California between 2005 and 2020 and where Domoic Acid Events are frequently occurring in the same period. Results showed that algal productivity is generally higher in Northern and Central CA with a major hotspot near the Monterey-Santa Cruz County border. Fishing dependencies of CA Counties are also calculated from NOAA’s CSVI to identify communities “vulnerable” to Harmful Algal Blooms
Quantifying the Contribution of Lower Limb Compensation to Upright Posture: What Happens if Adult Spinal Deformity Patients Do Not Compensate?
No full textStudy designThis is a multicenter, prospective cohort study.ObjectiveThis study tests the hypothesis that elimination of lower limb compensation in patients with adult spinal deformity (ASD) will significantly increase the magnitude of sagittal malalignment.Summary of background dataASD affects a significant proportion of the elderly population, impairing functional sagittal alignment and inhibiting overall quality of life. To counteract these effects, patients with ASD use their spine, pelvis, and lower limbs to create a compensatory posture that allows for standing and mobility. However, the degree to which each of the hips, knees, and ankles contributes to these compensatory mechanisms has yet to be determined.MethodsPatients undergoing corrective surgery for ASD were included if they met at least one of the following criteria: complex surgical procedure, geriatric deformity surgery, or severe radiographic deformity. Preoperative full-body x-rays were evaluated, and age and PI-adjusted normative values were used to model spine alignment based upon three positions: compensated (all lower extremity compensatory mechanisms maintained), partially compensated (removal of ankle dorsiflexion and knee flexion, with maintained hip extension), and uncompensated (ankle, knee, and hip compensation set to the age and PI norms).Results288 patients were included (mean age 60 y, 70.5% females). As the model transitioned from the compensated to uncompensated position, initial posterior translation of the pelvis decreased significantly to an anterior translation versus the ankle (P.Shift: 30 to -7.6 mm). This was associated with a decrease in pelvic retroversion (PT: 24.1 to 16.1), hip extension (SFA: 203 to 200), knee flexion (KA: 5.5 to-0.4), and ankle dorsiflexion (AA: 5.3 to 3.7). As a result, the anterior malalignment of the trunk significantly increased: SVA (65 to 120 mm) and G-SVA (C7-Ankle from 36 to 127 mm).ConclusionRemoval of lower limbs compensation revealed an unsustainable truncal malalignment with two-fold greater SVA
Rapidly progressing mycotic aortic aneurysm masquerading as acute coronary syndrome.
No full textMycotic aortic aneurysms are rare. The most common cause of a mycotic aortic aneurysm is bacterial seeding in a diseased or injured aortic intima with subsequent arteritis. Because the clinical presentation of mycotic aortic aneurysms can be quite variable, the diagnosis hence can often be quite challenging. We herewith report an interesting case study in which the patient with a mycotic aortic aneurysm presented with the clinical picture masquerading as an acute coronary syndrome. The scenario reiterates the fact that despite the availability of accurate noninvasive imaging techniques, strong clinical suspicion might be imperative for the diagnosis of mycotic aneurysms
NMR-based Structural Analysis of Threonylcarbamoyl-AMP Synthase and Its Substrate Interactions.
No full textThe hypermodified nucleoside N(6)-threonylcarbamoyladenosine (t(6)A37) is present in many distinct tRNA species and has been found in organisms in all domains of life. This post-transcriptional modification enhances translation fidelity by stabilizing the anticodon/codon interaction in the ribosomal decoding site. The biosynthetic pathway of t(6)A37 is complex and not well understood. In bacteria, the following four proteins have been discovered to be both required and sufficient for t(6)A37 modification: TsaC, TsaD, TsaB, and TsaE. Of these, TsaC and TsaD are members of universally conserved protein families. Although TsaC has been shown to catalyze the formation of L-threonylcarbamoyl-AMP, a key intermediate in the biosynthesis of t(6)A37, the details of the enzymatic mechanism remain unsolved. Therefore, the solution structure of Escherichia coli TsaC was characterized by NMR to further study the interactions with ATP and L-threonine, both substrates of TsaC in the biosynthesis of L-threonylcarbamoyl-AMP. Several conserved amino acids were identified that create a hydrophobic binding pocket for the adenine of ATP. Additionally, two residues were found to interact with L-threonine. Both binding sites are located in a deep cavity at the center of the protein. Models derived from the NMR data and molecular modeling reveal several sites with considerable conformational flexibility in TsaC that may be important for L-threonine recognition, ATP activation, and/or protein/protein interactions. These observations further the understanding of the enzymatic reaction catalyzed by TsaC, a threonylcarbamoyl-AMP synthase, and provide structure-based insight into the mechanism of t(6)A37 biosynthesis
FOOT ALIGNMENT IN SYMPTOMATIC NATIONAL FOOTBALL LEAGUE (NFL) ATHLETES: A WEIGHTBEARING CT ANALYSIS.
No full textObjectiveOur aim was to describe the foot alignment in National Football League (NFL) players with different symptomatic foot and ankle pathologies using weightbearing cone-beam computed tomography (WBCBCT), comparing them to normally aligned feet as control group.Methods41 feet (36 active NFL players) were assessed using WBCBCT and compared to 20 normally aligned controls from a normal population. Measurements included: Foot and Ankle Offset (FAO); Calcaneal Offset (CO); Hindfoot Alignment Angle (HAA); angle between inferior and superior facets of the talus (Inftal-Suptal); angle between inferior facet of the talus and the horizontal/floor (Inftal-Hor); Forefoot Arch Angle (FAA); navicular- and medial cuneiform-to-floor distance.ResultsNFL athletes showed a neutrally aligned hindfoot when compared to controls (FAO: 1% vs 0.5%; CO: 2.3 mm vs 0.8 mm; HAA: 2.9° vs 0.8° in two groups, with all p > 0.05) and a normal morphology of the subtalar joint (no difference in Inftal-Suptal and Inftal-Hor angles). Conversely, in athletes we found a decreased medial longitudinal arch (FAA: 15° vs 18.3°, p = 0.03) with smaller navicular (38.2 mm vs 42.2 mm, p = 0.03) and medial cuneiform (27 mm vs 31.3 mm, p = 0.01) mean distances to the floor when compared to controls.ConclusionIn our series, NFL players presented a lower medial longitudinal arch than controls but a neutrally aligned hindfoot. WBCBCT may help shed light on anatomical risk factors for injuries in professional players. Level of Evidence III, Retrospective comparative study.</b