Does vibrotactile stimulation of the auricular vagus nerve enhance working memory? A behavioral and physiological investigation.

BACKGROUND: Working memory is essential to a wide range of cognitive functions and activities. Transcutaneous auricular vagus nerve stimulation (taVNS) is a promising method to improve working memory performance. However, the feasibility and scalability of electrical stimulation are constrained by several limitations, such as auricular discomfort and inconsistent electrical contact. OBJECTIVE: We aimed to develop a novel and practical method, vibrotactile taVNS, to improve working memory. Further, we investigated its effects on arousal, measured by skin conductance and pupil diameter. METHOD: This study included 20 healthy participants. Behavioral response, skin conductance, and eye tracking data were concurrently recorded while the participants performed N-back tasks under three conditions: vibrotactile taVNS delivered to the cymba concha, earlobe (sham control), and no stimulation (baseline control). RESULTS: In 4-back tasks, which demand maximal working memory capacity, active vibrotactile taVNS significantly improved the performance metric d' compared to the baseline but not to the sham. Moreover, we found that the reduction rate of d' with increasing task difficulty was significantly smaller during vibrotactile taVNS sessions than in both baseline and sham conditions. Arousal, measured as skin conductance and pupil diameter, declined over the course of the tasks. Vibrotactile taVNS rescued this arousal decline, leading to arousal levels corresponding to optimal working memory levels. Moreover, pupil diameter and skin conductance level were higher during high-cognitive-load tasks when vibrotactile taVNS was delivered to the concha compared to baseline and sham. CONCLUSION: Our findings suggest that vibrotactile taVNS modulates the arousal pathway and could be a potential intervention for enhancing working memory.

Does Vibrotactile Stimulation of the Auricular Vagus Nerve Enhance Working Memory? A Behavioral and Physiological Investigation.

Background: Working memory is essential to a wide range of cognitive functions and activities. Transcutaneous auricular VNS (taVNS) is a promising method to improve working memory performance. However, the feasibility and scalability of electrical stimulation are constrained by several limitations, such as auricular discomfort and inconsistent electrical contact. Objective: We aimed to develop a novel and practical method, vibrotactile taVNS, to improve working memory. Further, we investigated its effects on arousal, measured by skin conductance and pupil diameter. Method: This study included 20 healthy participants. Behavioral response, skin conductance, and eye tracking data were concurrently recorded while the participants performed N-back tasks under three conditions: vibrotactile taVNS delivered to the cymba concha, earlobe (sham control), and no stimulation (baseline control). Results: In 4-back tasks, which demand maximal working memory capacity, active vibrotactile taVNS significantly improved the performance metric d ' compared to the baseline but not to the sham. Moreover, we found that the reduction rate of d ' with increasing task difficulty was significantly smaller during vibrotactile taVNS sessions than in both baseline and sham conditions. Arousal, measured as skin conductance and pupil diameter, declined over the course of the tasks. Vibrotactile taVNS rescued this arousal decline, leading to arousal levels corresponding to optimal working memory levels. Moreover, pupil diameter and skin conductance level were higher during high-cognitive-load tasks when vibrotactile taVNS was delivered to the concha compared to baseline and sham. Conclusion: Our findings suggest that vibrotactile taVNS modulates the arousal pathway and could be a potential intervention for enhancing working memory. Highlights: Vibrotactile stimulation of the auricular vagus nerve increases general arousal.Vibrotactile stimulation of the auricular vagus nerve mitigates arousal decreases as subjects continuously perform working memory tasks.6 Hz Vibrotactile auricular vagus nerve stimulation is a potential intervention for enhancing working memory performance.

Global assessment of marine plastic exposure risk for oceanic birds.

Plastic pollution is distributed patchily around the world's oceans. Likewise, marine organisms that are vulnerable to plastic ingestion or entanglement have uneven distributions. Understanding where wildlife encounters plastic is crucial for targeting research and mitigation. Oceanic seabirds, particularly petrels, frequently ingest plastic, are highly threatened, and cover vast distances during foraging and migration. However, the spatial overlap between petrels and plastics is poorly understood. Here we combine marine plastic density estimates with individual movement data for 7137 birds of 77 petrel species to estimate relative exposure risk. We identify high exposure risk areas in the Mediterranean and Black seas, and the northeast Pacific, northwest Pacific, South Atlantic and southwest Indian oceans. Plastic exposure risk varies greatly among species and populations, and between breeding and non-breeding seasons. Exposure risk is disproportionately high for Threatened species. Outside the Mediterranean and Black seas, exposure risk is highest in the high seas and Exclusive Economic Zones (EEZs) of the USA, Japan, and the UK. Birds generally had higher plastic exposure risk outside the EEZ of the country where they breed. We identify conservation and research priorities, and highlight that international collaboration is key to addressing the impacts of marine plastic on wide-ranging species.

Wound repair, safety, and functional outcomes in reconstructive lower extremity foot and ankle surgery using a dehydrated amnion/chorion allograft membrane.

Amniotic membranes are known to be rich in growth factors, cytokines, and matrix proteins, which can help support wound closure and may improve patient outcomes in foot and ankle surgical interventions. In this Institutional Review Board (IRB) approved clinical study, 21 consecutive patients undergoing lower extremity soft tissue and bone reconstruction surgery received dehydrated human amnion and chorion allograft (dHACA) placed as a covering over the deep layers of the surgical wound during closure. Wound healing complications were assessed and American Orthopaedic Foot and Ankle Society (AOFAS) scores were compiled from over a 1-year follow-up period. Summary statistics were calculated for average pain, function, and alignment. The average overall AOFAS pre-treatment score was 35.8 ± 23.0 and the post-treatment score significantly improved to 87.5 ± 6.4 (P = 3.7 × 10-10 ). The pain-score improved from pre-treatment at 10.0 ± 11.0 to post-treatment at 36.7 ± 4.8 (P = 5.0 × 10-5 ). The pre-treatment function score was 18.7 ± 12.9 and at post-treatment increased to 38.5 ± 5.7 (P = 5.8 × 10-5 ). Lastly, the alignment score at pre-treatment was 7.1 ± 4.4 and at post-treatment was 12.4 ± 2.6 (P = .001). These improvements in functional scores were accompanied with clinical observations of reduced surgical complications including a lack of wound dehisance in the cohort. These clinical findings suggest that the application of aseptically processed dHACA may reduce wound complications and as such may aide in clinical improvements in foot and ankle surgical interventions however a larger comparative trial should be considered to validate these initial findings.

Global political responsibility for the conservation of albatrosses and large petrels.

Migratory marine species cross political borders and enter the high seas, where the lack of an effective global management framework for biodiversity leaves them vulnerable to threats. Here, we combine 10,108 tracks from 5775 individual birds at 87 sites with data on breeding population sizes to estimate the relative year-round importance of national jurisdictions and high seas areas for 39 species of albatrosses and large petrels. Populations from every country made extensive use of the high seas, indicating the stake each country has in the management of biodiversity in international waters. We quantified the links among national populations of these threatened seabirds and the regional fisheries management organizations (RFMOs) which regulate fishing in the high seas. This work makes explicit the relative responsibilities that each country and RFMO has for the management of shared biodiversity, providing invaluable information for the conservation and management of migratory species in the marine realm.

Does perspective matter? A case study comparing Eulerian and Lagrangian estimates of common murre (Uria aalge) distributions.

Studies estimating species' distributions require information about animal locations in space and time. Location data can be collected using surveys within a predetermined frame of reference (i.e., Eulerian sampling) or from animal-borne tracking devices (i.e., Lagrangian sampling). Integration of observations obtained from Eulerian and Lagrangian perspectives can provide insights into animal movement and habitat use. However, contemporaneous data from both perspectives are rarely available, making examination of biases associated with each sampling approach difficult. We compared distributions of a mobile seabird observed concurrently from ship, aerial, and satellite tag surveys during May, June, and July 2012 in the northern California Current. We calculated utilization distributions to quantify and compare variability in common murre (Uria aalge) space use and examine how sampling perspective and platform influence observed patterns. Spatial distributions of murres were similar in May, regardless of sampling perspective. Greatest densities occurred in coastal waters off southern Washington and northern Oregon, near large murre colonies and the mouth of the Columbia River. Density distributions of murres estimated from ship and aerial surveys in June and July were similar to those observed in May, whereas distributions of satellite-tagged murres in June and July indicated northward movement into British Columbia, Canada, resulting in different patterns observed from Eulerian and Lagrangian perspectives. These results suggest that the population of murres observed in the northern California Current during spring and summer includes relatively stationary individuals attending breeding colonies and nonstationary, vagile adults and subadults. Given the expected growth of telemetry studies and advances in survey technology (e.g., unmanned aerial systems), these results highlight the importance of considering methodological approaches, spatial extent, and synopticity of distribution data sets prior to integrating data from different sampling perspectives.

Collision and displacement vulnerability to offshore wind energy infrastructure among marine birds of the Pacific Outer Continental Shelf.

Marine birds are vulnerable to collision with and displacement by offshore wind energy infrastructure (OWEI). Here we present the first assessment of marine bird vulnerability to potential OWEI in the California Current System portion of the U.S. Pacific Outer Continental Shelf (POCS). Using population size, demography, life history, flight heights, and avoidance behavior for 62 seabird and 19 marine water bird species that occur in the POCS, we present and apply equations to calculate Population Vulnerability, Collision Vulnerability, and Displacement Vulnerability to OWEI for each species. Species with greatest Population vulnerability included those listed as species of concern (e.g., Least Tern [Sternula antillarum], Marbled Murrelet [Brachyramphus marmoratus], Pink-footed Shearwater [Puffinus creatopus]) and resident year-round species with small population sizes (e.g., Ashy Storm-Petrel [Oceanodroma homochroa], Brandt's Cormorant [Phalacrocorax penicillatus], and Brown Pelican [Pelecanus occidentalis]). Species groups with the greatest Collision Vulnerability included jaegers/skuas, pelicans, terns and gulls that spend significant amounts of time flying at rotor sweep zone height and don't show macro-avoidance behavior (avoidance of entire OWEI area). Species groups with the greatest Displacement Vulnerability show high macro-avoidance behavior and low habitat flexibility and included loons, grebes, sea ducks, and alcids. Using at-sea survey data from the southern POCS, we combined species-specific vulnerabilities described above with at-sea species densities to assess vulnerabilities spatially. Spatial vulnerability densities were greatest in areas with high species densities (e.g., near-shore areas) and locations where species with high vulnerability were found in abundance. Our vulnerability assessment helps understand and minimize potential impacts of OWEI infrastructure on marine birds in the POCS and could inform management decisions.

Carotenoid-based skin ornaments reflect foraging propensity in a seabird, Sula leucogaster.

Carotenoid-based ornaments are common signalling features in animals. It has long been proposed that such ornaments communicate information about foraging abilities to potential mates. However, evidence linking foraging with ornamentation is largely missing from unmanipulated, free-ranging populations. To investigate this relationship, we studied a coastal population of brown booby (Sula leucogaster brewsteri), a seabird with a carotenoid-based gular skin ornament. δ13C values from both feathers and blood plasma were negatively correlated with male gular colour, indicating birds that consumed more pelagic prey in offshore locations had more ornamented skin than those that fed on nearshore, benthic prey. This relationship was supported by our GPS tracking results, which revealed longer, more offshore foraging trips among highly ornamented males. Our data show that brown booby ornaments are honest indicators of foraging propensity; a link consistent with the rarity hypothesis and potentially driven by the concentration of carotenoids found in phytoplankton versus benthic algae. Carotenoid-based ornaments may reflect foraging tendencies in animals such as coastal predators that use food webs with distinct carotenoid profiles.

Population-level plasticity in foraging behavior of western gulls (Larus occidentalis).

BACKGROUND: Plasticity in foraging behavior among individuals, or across populations may reduce competition. As a generalist carnivore, western gulls (Larus occidentalis) consume a wide range of marine and terrestrial foods. However, the foraging patterns and habitat selection (ocean or land) of western gulls is not well understood, despite their ubiquity in coastal California. Here, we used GPS loggers to compare the foraging behavior and habitat use of western gulls breeding at two island colonies in central California. RESULTS: Gulls from offshore Southeast Farallon Island (SFI; n = 41 gulls) conducted more oceanic trips (n = 90) of shorter duration (3.8 ± 3.3 SD hours) and distance (27.1 ± 20.3 km) than trips to the mainland (n = 41) which were nearly 4 times longer and 2 times farther away. In contrast, gulls from coastal Año Nuevo Island (ANI; n = 20 gulls) foraged at sites on land more frequently (n = 103) but trip durations (3.6 ± 2.4 h) and distances (20.8 ± 9.4 km) did not differ significantly from oceanic trips (n = 42) where trip durations were only slightly shorter (2.9 ± 2.7 h) and equidistant (20.6 ± 12.1 km). Gulls from both colonies visited more sites while foraging at sea but spent significantly longer (3-5 times) durations at each site visited on land. Foraging at sea was also more random compared to foraging trips over land where gulls from both colonies visited the same sites on multiple trips. The total home range of gulls from SFI (14,230 km2) was 4.5 times larger than that of gulls from ANI, consistent with greater resource competition resulting from a larger abundance of seabirds at SFI. CONCLUSIONS: Population-level plasticity in foraging behavior was evident and dependent on habitat type. In addition, gulls from SFI were away foraging longer than gulls from ANI (22% vs. 7.5%, respectively), which impacts the defense of territories and attempts at nest predation by conspecifics. Our results can be used to explain lower chick productivity at SFI, and can provide insight into increased gull activity in urban areas.

Cu from dissolution of CuO nanoparticles signals changes in root morphology.

Utilization of CuO nanoparticles (NPs) in agriculture, as fertilizers or pesticides, requires understanding of their impact on plant metabolism. Inhibition of root elongation by CuO NPs (>10 mg Cu/kg) occurred in wheat grown in sand. Morphological changes included root hair proliferation and shortening of the zones of division and elongation. The epidermal cells in the compressed root tip were abnormal in shape and file patterning but staining with SYTOX Blue did not reveal a general increase in epidermal cell death. Inhibition of root elongation and proliferation of root hair formation occurred also in response to exogenous indole acetic acid (IAA) supplied through tryptophan metabolism by the root-colonizing bacterium, Pseudomonas chlororaphis O6. Altered root morphology caused by the CuO NPs was likely due to release of Cu from dissolution at the root surface because similar changes occurred with Cu ions (≥6 mg/kg). Use of a fluorescent probe showed the accumulation of nitric oxide (NO), required for root hair formation, was not changed by the NPs. These findings suggested that dissolution of the NPs in the rhizosphere resulted levels of Cu that modified IAA distribution to causing root shortening but permitted NO cell signaling to promote root hair proliferation.

Leclercia adecarboxylata bacteremia in a trauma patient: case report and review of the literature.

BACKGROUND: Leclercia adecarboxylata is a rarely described gram-negative pathogen. Since the advent of rapid molecular typing techniques, L. adecarboxylata has been described in 23 case reports, often associated with polymicrobial infections or in immunosuppressed hosts. METHODS: A case is described and previous cases of L. adecarboxylata infection are reviewed. CASE REPORT: A 55-year old male victim of trauma developed septic shock several days after presentation to the emergency department. Blood and central vein catheter cultures grew L. adecarboxylata; Haemophilus influenzae and Streptococcus pneumoniae were present in bronchoalveolar lavage samples. With aggressive hemodynamic and ventilator support in addition to antibiotic therapy, the patient cleared the catheter-related blood stream infection. After a challenging intensive care unit stay, the patient eventually was discharged to an inpatient rehabilitation unit. CONCLUSION: An L. adecarboxylata catheter-related blood stream infection developed in the setting of both underlying immunosuppression and polymicrobial infection. As molecular typing techniques continue to improve, L. adecarboxylata is likely to be an increasingly recognized gram-negative pathogen. Interactions between L. adecarboxylata infection, immunosuppression, and polymicrobial infections remain to be elucidated.

Foraging segregation and genetic divergence between geographically proximate colonies of a highly mobile seabird.

Foraging segregation may play an important role in the maintenance of animal diversity, and is a proposed mechanism for promoting genetic divergence within seabird species. However, little information exists regarding its presence among seabird populations. We investigated genetic and foraging divergence between two colonies of endangered Hawaiian petrels (Pterodroma sandwichensis) nesting on the islands of Hawaii and Kauai using the mitochondrial Cytochrome b gene and carbon, nitrogen and hydrogen isotope values (δ(13)C, δ(15)N and δD, respectively) of feathers. Genetic analyses revealed strong differentiation between colonies on Hawaii and Kauai, with Φ(ST) = 0.50 (p < 0.0001). Coalescent-based analyses gave estimates of <1 migration event per 1,000 generations. Hatch-year birds from Kauai had significantly lower δ(13)C and δ(15)N values than those from Hawaii. This is consistent with Kauai birds provisioning chicks with prey derived from near or north of the Hawaiian Islands, and Hawaii birds provisioning young with prey from regions of the equatorial Pacific characterized by elevated δ(15)N values at the food web base. δ(15)N values of Kauai and Hawaii adults differed significantly, indicating additional foraging segregation during molt. Feather δD varied from -69 to 53‰. This variation cannot be related solely to an isotopically homogeneous ocean water source or evaporative water loss. Instead, we propose the involvement of salt gland excretion. Our data demonstrate the presence of foraging segregation between proximately nesting seabird populations, despite high species mobility. This ecological diversity may facilitate population coexistence, and its preservation should be a focus of conservation strategies.

Motivational narratives and assessments of the body after cosmetic surgery.

Cosmetic surgery can be conceptualized as part of a spectrum of contemporary body projects whereby the individual uses body work to achieve some social and personal goal. In this article I examine individual motivations for undergoing cosmetic surgery as well as assessments of the outcomes of those surgeries. Drawing on in-depth interviews, I explore how cosmetic surgery patients understand and ascribe meaning to their own experiences and discover how the respondents evaluate their surgeries in both personal and social contexts. I found that motivations for undergoing surgery are often articulated in both physical and psychosocial terms, with the expectation that physical alterations will facilitate social or emotional changes. Additionally, outcomes are assessed in a similar fashion, with interviewees expressing not only their evaluations of the aesthetic changes to their bodies, but also how these changes made them feel about themselves and their relationships with others.