Exploring efficacy in personal constraint negotiation: an ethnography of mountaineering tourists

Limited work has explored the relationship between efficacy and personal constraint negotiation for adventure tourists, yet efficacy is pivotal to successful activity participation as it influences people’s perceived ability to cope with constraints, and their decision to use negotiation strategies. This paper explores these themes with participants of a commercially organised mountaineering expedition. Phenomenology-based ethnography was adopted to appreciate the social and cultural mountaineering setting from an emic perspective. Ethnography is already being used to understand adventure participation, yet there is considerable scope to employ it further through researchers immersing themselves into the experience. The findings capture the interaction between the ethnographer and the group members, and provide an embodied account using their lived experiences. Findings reveal that personal mountaineering skills, personal fitness, altitude sickness and fatigue were the four key types of personal constraint. Self-efficacy, negotiation-efficacy and other factors, such as hardiness and motivation, influenced the effectiveness of negotiation strategies. Training, rest days, personal health, and positive self-talk were negotiation strategies. A conceptual model illustrates these results and demonstrates the interplay between efficacy and the personal constraint negotiation journey for led mountaineers

The Effects of Two Types of Sleep Deprivation on Visual Working Memory Capacity and Filtering Efficiency

Sleep deprivation has adverse consequences for a variety of cognitive functions. The exact effects of sleep deprivation, though, are dependent upon the cognitive process examined. Within working memory, for example, some component processes are more vulnerable to sleep deprivation than others. Additionally, the differential impacts on cognition of different types of sleep deprivation have not been well studied. The aim of this study was to examine the effects of one night of total sleep deprivation and 4 nights of partial sleep deprivation (4 hours in bed/night) on two components of visual working memory: capacity and filtering efficiency. Forty-four healthy young adults were randomly assigned to one of the two sleep deprivation conditions. All participants were studied: 1) in a well-rested condition (following 6 nights of 9 hours in bed/night); and 2) following sleep deprivation, in a counter-balanced order. Visual working memory testing consisted of two related tasks. The first measured visual working memory capacity and the second measured the ability to ignore distractor stimuli in a visual scene (filtering efficiency). Results showed neither type of sleep deprivation reduced visual working memory capacity. Partial sleep deprivation also generally did not change filtering efficiency. Total sleep deprivation, on the other hand, did impair performance in the filtering task. These results suggest components of visual working memory are differentially vulnerable to the effects of sleep deprivation, and different types of sleep deprivation impact visual working memory to different degrees. Such findings have implications for operational settings where individuals may need to perform with inadequate sleep and whose jobs involve receiving an array of visual information and discriminating the relevant from the irrelevant prior to making decisions or taking actions (e.g., baggage screeners, air traffic controllers, military personnel, health care providers)

Role of hydrophobicity, aromaticity, and turn nucleation in peptide self-assembly

Thesis (Ph. D.)--University of Rochester. Dept. of Chemistry, 2012.Peptide self-assembly into cross-β amyloid is the hallmark of several amyloid pathologies and the inspiration for biomaterials. Peptide self-assembly is governed by noncovalent interactions such as hydrophobic, electrostatic, aromatic, and van der Waals interactions. Aromatic interactions, a specific subset of hydrophobic interactions, have been proposed to play an essential role during amyloid peptide self-assembly. Others contend that the high hydrophobicity and favorable planar geometry of aromatic residues are responsible for the prevalence of these residues in self-assembling peptides. Using a model peptide that self-assembles into fibrils where π−π interactions are not likely to occur, we mutated the single Phe residue with several natural and nonnatural amino acids that varied in hydrophobicity, aromaticity and molecular volume. We performed kinetic and thermodynamic analyses on variant self-assembly and showed that stabilization imparted by aromatic amino acids is a function of their high hydrophobicity and favorable planar geometry, and not the ability to form specific π−π interactions. In the latter part of this thesis, the effect of turn nucleation on peptide selfassembly is examined. Structural models of the amyloid-β peptide (Aβ) in various stages of aggregation consistently indicate the presence of a β-hairpin (pre-oligomeric structures) or β-turn (oligomers and fibrils). We tested the effects of turn nucleation as a potential rate-limiting step in Aβ self-assembly. We incorporated a β-hairpin nucleator, D-ProGly (DPG) into the putative turn region of Aβ40 and found that turn nucleation generally enhanced the kinetics of self-assembly. Cytotoxicity of the variants in different states of assembly indicated that β-hairpin formation likely precedes cytotoxic oligomer formation. Based on these results, we incorporated an azobenzene turn mimetic into the 25–27 region of Aβ to gain temporal control over fibril nucleation and gain mechanistic insight into Aβ self-assembly through turn nucleation. Finally, we used the azobenzene turn mimetic to alter the secondary structure of a peptide hydrogel, (RADA)4. Reversible disruption of the hydrogel fibril network was achieved through trans → cis isomerization resulting in weakened rigidity. The work reported in this thesis has clarified the role of hydrophobicity, aromatic π−π interactions and turn nucleation on amyloid self-assembly processes

Discovery of Native Autoantigens via Antigen Surrogate Technology: Application to Type 1 Diabetes

A fundamental goal in understanding the mechanisms of autoimmune disease is the characterization of autoantigens that are targeted by autoreactive antibodies and T cells. Unfortunately, the identification of autoantigens is a difficult problem. We have begun to explore a novel route to the discovery of autoantibody/autoantigen pairs that involves comparative screening of combinatorial libraries of unnatural, synthetic molecules for compounds that bind antibodies present at much higher levels in the serum of individuals with a given autoimmune disease than in the serum of control individuals. We have shown that this approach can yield “antigen surrogates” capable of capturing disease-specific autoantibodies from serum. In this report, we demonstrate that the synthetic antigen surrogates can be used to affinity purify the autoantibodies from serum and that these antibodies can then be used to identify their cognate autoantigen in an appropriate tissue lysate. Specifically, we report the discovery of a peptoid able to bind autoantibodies present in about one-third of nonobese diabetic (NOD) mice. The peptoid-binding autoantibodies were highly enriched through peptoid affinity chromatography and employed to probe mouse pancreatic and brain lysates. This resulted in identification of murine GAD65 as the native autoantigen. GAD65 is a known humoral autoantigen in human type 1 diabetes mellitus (T1DM), but its existence in mice had been controversial. This study demonstrates the potential of this chemical approach for the unbiased identification of autoantigen/autoantibody complexes

Attenuation of Responses of Waterbirds to Repeat Drone Surveys Involving a Sequence of Altitudes and Drone Types: A Case Study

Remotely piloted aircraft systems (RPAS, or ‘drones’ hereafter) have potential for surveying waterbird species and habitats, but there is a risk that the disturbance from drones could compromise count accuracy and bird welfare. We examined the response of 16 waterbird species to repeated up-and-back overhead drone flights (n = 50 flights) at multiple flight heights (80, 60, 40 and 20 m) using three common drone platforms (DJI Matrice 300, DJI Mavic 2 Enterprise Advanced and DJI Phantom 4). A ground observer scored the species’ responses to overhead drone flights, which ranged from no response (no change to initial behavior), vigilance (head turning and tracking), movement within the site (swimming, diving, flight into or on the water) and substantial flight resulting in departure from the pond (fleeing). A total of 280 waterbird encounters with overhead drones were observed. The most common response across all flights was no response (70.7%), followed by vigilance (27.5%), whereas more intense responses were comparatively rare (1.8%). The responses were of higher intensity during earlier overhead drone flights, before moderating substantially during later flights. Thus, our case study provides the first unambiguous evidence of the attenuation of responses of bird species to drones

Alcohol tax reform: now is the time

TO THE EDITOR: Alcohol misuse is one of the leading causes of preventable death, illness and injury in Australia because too many Australians drink too much alcohol too often. The evidence is clear on what are the most effective strategies to curb alcohol misuse at a population level. By far the most effective of these is increasing the price of alcohol by increasing alcohol taxes

Modulating Supramolecular Peptide Hydrogel Viscoelasticity Using Biomolecular Recognition

Self-assembled peptide-based hydrogels are emerging materials that have been exploited for wound healing, drug delivery, tissue engineering, and other applications. In comparison to synthetic polymer hydrogels, supramolecular peptide-based gels have advantages in biocompatibility, biodegradability, and ease of synthesis and modification. Modification of the emergent viscoelasticity of peptide hydrogels in a stimulus responsive fashion is a longstanding goal in the development of next-generation materials. In an effort to selectively modulate hydrogel viscoelasticity, we report herein a method to enhance the elasticity of β-sheet peptide hydrogels using specific molecular recognition events between functionalized hydrogel fibrils and biomolecules. Two distinct biomolecular recognition strategies are demonstrated: oligonucleotide Watson–Crick duplex formation between peptide nucleic acid (PNA) modified fibrils with a bridging oligonucleotide and protein–ligand recognition between mannose modified fibrils with concanavalin A. These methods to modulate hydrogel elasticity should be broadly adaptable in the context of these materials to a wide variety of molecular recognition partners