A New Lungworm in Muskoxen: an Exploration in Arctic Parasitology

Ruminants are vital elements of the Holarctic ecosystem. Little is known, however, of the structure or biology of their parasite fauna, particularly in North America. Global warming, coupied with increasing human activity in the Arctic, requires enhanced intemational interdisciplinary efforts to better understand the many factors, including parasites, that influence the population health of caribou, reindeer, muskoxen and wild sheep. The discovery of an unusual new genus of protostrongylid lung nematode in muskoxen from the central Canadian Arctic is described, and the intricacies of the parasite\u27s relationship with its muskoxen definitive hosts, its gastropod intermediate hosts and the arctic environment are discussed

Global Warming Is Changing the Dynamics of Arctic Host-Parasite Systems

Global climate change is altering the ecology of infectious agents and driving the emergence of disease in people, domestic animals, and wildlife. We present a novel, empirically based, predictive model for the impact of climate warming on development rates and availability of an important parasitic nematode of muskoxen in the Canadian Arctic, a region that is particularly vulnerable to climate change. Using this model, we show that warming in the Arctic may have already radically altered the transmission dynamics of this parasite, escalating infection pressure for muskoxen, and that this trend is expected to continue. This work establishes a foundation for understanding responses to climate change of other host-parasite systems, in the Arctic and globally

Global Warming Is Changing the Dynamics of Arctic Host-Parasite Systems

Global climate change is altering the ecology of infectious agents and driving the emergence of disease in people, domestic animals, and wildlife. We present a novel, empirically based, predictive model for the impact of climate warming on development rates and availability of an important parasitic nematode of muskoxen in the Canadian Arctic, a region that is particularly vulnerable to climate change. Using this model, we show that warming in the Arctic may have already radically altered the transmission dynamics of this parasite, escalating infection pressure for muskoxen, and that this trend is expected to continue. This work establishes a foundation for understanding responses to climate change of other host-parasite systems, in the Arctic and globally

C3–C4 composition and prior carbon dioxide treatment regulate the response of grassland carbon and water fluxes to carbon dioxide

During May, July and October 2000, we measured the effects of temporarily increasing or decreasing CO2 concentration by 150–200 μmol mol−1 on daytime net ecosystem CO2 exchange (NEE) and water flux (evapotranspiration, ET) of C3–C4 grassland in central Texas, USA that had been exposed for three growing seasons to a CO2 gradient from 200 to 560 μmol mol−1. Grassland grown at subambient CO2 (\u3c 365 μmol mol−1) was exposed for 2 days to an elevated CO2 gradient (\u3e 365 μmol mol−1). Grassland grown at elevated CO2 was exposed for 2 days to a subambient gradient. Our objective was to determine whether growth CO2 affected the amount by which grassland NEE and ET responded to CO2 switching (sensitivity to CO2)

Perturbative Expansion around the Gaussian Effective Action: The Background Field Method

We develop a systematic method of the perturbative expansion around the Gaussian effective action based on the background field method. We show, by applying the method to the quantum mechanical anharmonic oscillator problem, that even the first non-trivial correction terms greatly improve the Gaussian approximation.Comment: 16 pages, 3 eps figures, uses RevTeX and epsf. Errors in Table 1 are corrected and new references are adde

Net grassland carbon flux over a subambient to superambient CO2 gradient

Increasing atmospheric CO2 concentrations may have a profound effect on the structure and function of plant communities. A previously grazed, central Texas grassland was exposed to a 200-µmol mol-1 to 550 µmol mol-1 CO2 gradient from March to mid-December in 1998 and 1999 using two, 60-m long, polyethylene-covered chambers built directly onto the site. One chamber was operated at subambient CO2 concentrations (200-360 µmol mol-1 daytime) and the other was regulated at superambient concentrations (360-550 µmol mol-1). Continuous CO2 gradients were maintained in each chamber by photosynthesis during the day and respiration at night. Net ecosystem CO2 flux and end-of-year biomass were measured in each of 10, 5-m long sections in each chamber. Net CO2 fluxes were maximal in late May (c. day 150) in 1998 and in late August in 1999 (c. day 240). In both years, fluxes were near zero and similar in both chambers at the beginning and end of the growing season. Average daily CO2 flux in 1998 was 13 g CO2 m-2 day-1 in the subambient chamber and 20 g CO2 m-2 day-1 in the superambient chamber; comparable averages were 15 and 26 g CO2 m-2 day-1 in 1999. Flux was positively and linearly correlated with end-of-year above-ground biomass but flux was not linearly correlated with CO2 concentration; a finding likely to be explained by inherent differences in vegetation. Because C3 plants were the dominant functional group, we adjusted average daily flux in each section by dividing the flux by the average percentage C3 cover. Adjusted fluxes were better correlated with CO2 concentration, although scatter remained. Our results indicate that after accounting for vegetation differences, CO2 flux increased linearly with CO2 concentration. This trend was more evident at subambient than superambient CO2 concentrations

U(1) Gauge Theory with Villain Action on Spherical Lattices

We have studied the U(1) gauge field theory with Villain (periodic Gaussian) action on spherelike lattices. The effective size of the systems studied ranges from 6 to 16. We do not observe any 2-state signal in the distribution function of the plaquette expectation value at the deconfining phase transition. The observed finite-size scaling behavior is consistent with a second order phase transition. The obtained value of the critical exponent is nu =0.366(12) and thus neither Gaussian (nu = 0.5) nor discontinuous (nu=0.25) type, indicating a nontrivial continuum limit.Comment: 10 pages, LaTeX, 2 figure

The Apple Watch for monitoring mental health–related physiological symptoms : literature review

Background: An anticipated surge in mental health service demand related to COVID-19 has motivated the use of novel methods of care to meet demand, given workforce limitations. Digital health technologies in the form of self-tracking technology have been identified as a potential avenue, provided sufficient evidence exists to support their effectiveness in mental health contexts. Objective: This literature review aims to identify current and potential physiological or physiologically related monitoring capabilities of the Apple Watch relevant to mental health monitoring and examine the accuracy and validation status of these measures and their implications for mental health treatment. Methods: A literature review was conducted from June 2021 to July 2021 of both published and gray literature pertaining to the Apple Watch, mental health, and physiology. The literature review identified studies validating the sensor capabilities of the Apple Watch. Results: A total of 5583 paper titles were identified, with 115 (2.06%) reviewed in full. Of these 115 papers, 19 (16.5%) were related to Apple Watch validation or comparison studies. Most studies showed that the Apple Watch could measure heart rate acceptably with increased errors in case of movement. Accurate energy expenditure measurements are difficult for most wearables, with the Apple Watch generally providing the best results compared with peers, despite overestimation. Heart rate variability measurements were found to have gaps in data but were able to detect mild mental stress. Activity monitoring with step counting showed good agreement, although wheelchair use was found to be prone to overestimation and poor performance on overground tasks. Atrial fibrillation detection showed mixed results, in part because of a high inconclusive result rate, but may be useful for ongoing monitoring. No studies recorded validation of the Sleep app feature; however, accelerometer-based sleep monitoring showed high accuracy and sensitivity in detecting sleep. Conclusions: The results are encouraging regarding the application of the Apple Watch in mental health, particularly as heart rate variability is a key indicator of changes in both physical and emotional states. Particular benefits may be derived through avoidance of recall bias and collection of supporting ecological context data. However, a lack of methodologically robust and replicated evidence of user benefit, a supportive health economic analysis, and concerns about personal health information remain key factors that must be addressed to enable broader uptake