Does the early frog catch the worm? Disentangling potential drivers of a parasite age–intensity relationship in tadpoles

The manner in which parasite intensity and aggregation varies with host age can provide insights into parasite dynamics and help identify potential means of controlling infections in humans and wildlife. A significant challenge is to distinguish among competing mechanistic hypotheses for the relationship between age and parasite intensity or aggregation. Because different mechanisms can generate similar relationships, testing among competing hypotheses can be difficult, particularly in wildlife hosts, and often requires a combination of experimental and model fitting approaches. We used field data, experiments, and model fitting to distinguish among ten plausible drivers of a curvilinear age–intensity relationship and increasing aggregation with host age for echinostome trematode infections of green frogs. We found little support for most of these proposed drivers but did find that the parsimonious explanation for the observed age–intensity relationship was seasonal exposure to echinostomes. The parsimonious explanation for the aggregated distribution of parasites in this host population was heterogeneity in exposure. A predictive model incorporating seasonal exposure indicated that tadpoles hatching early or late in the breeding season should have lower trematode burdens at metamorphosis, particularly with simulated warmer climates. Application of this multi-pronged approach (field surveys, lab experiments, and modeling) to additional parasite–host systems could lead to discovery of general patterns in the drivers of parasite age–intensity and age–distribution relationships

Alpha decay self-damage in cubic and monoclinic zirconolite

Samples of primarily-monoclinic /sup 238/Pu-doped zirconolite were stored at ambient temperature to allow accumulation of alpha decay self-damage to a dose of 1 x 10/sup 24/ ..cap alpha../m/sup 3/ (equivalent to a SYNROC age of approx. 10/sup 3/y). Bulk swelling reached 2.3 vol% with no tendency toward saturation, a damage response similar to that observed for cubic Pu-doped zirconolite. X-ray volumetric swelling at 4 x 10/sup 24/ ..cap alpha../m/sup 3/ was 1 vol%, considerably less than that for the cubic material. Changes in cell dimensions differed significantly from those reported by others for a monoclinic natural mineral. Extensive microcracking was observed, and is attributed at least partially to swelling differences between the matrix and minor phases

Integrated climate sensitive restoration framework for transformative changes to sustainable land restoration

Sustainable land restoration is the key to restore degraded land, halt biodiversity loss and reinstate ecosystem services for human well‐being. Restoration needs to be planned and conducted with due recognition to growing climate uncertainty with an evolved understanding about the future restoration targets. Present opinion article attempts to provide an overview on Integrated Climate Sensitive Restoration Framework that recognizes the local participation in mapping degraded lands, identification of species for supporting species modelling to better understand climate uncertainty. Involvement of citizen science based restoration monitoring tools can contribute to big data analytics for ecological monitoring and policy support. The Framework potentially helps in sustainable land restoration by transformative changes for achieving UN decade on Ecosystems Restoration (2021–2030), SDGs 15 and addressing the post 2020 Global Biodiversity Framework. However, to realize the success, climate finance mechanisms to drive restoration should be seriously considered for reducing bias and enhancing opportunities of equitable sharing in the era of corruption, authoritarianism and regulatory capture

Renalase Gene Polymorphisms in Patients With Type 2 Diabetes, Hypertension and Stroke

Renalase is a novel, recently identified, flavin adenine dinucleotide-dependent amine oxidase. It is secreted by the kidney and metabolizes circulating catecholamines. Renalase has significant hemodynamic effects, therefore it is likely to participate in the regulation of cardiovascular function.The aim of our study was to investigate the involvement of renalase gene polymorphisms in hypertension in type 2 diabetes patients. A total of 892 patients and 400 controls were genotyped with three SNPs in the renalase gene. The C allele of rs2296545 SNP was associated with hypertension (P < 0.01). For rs2576178 SNP, frequencies in hypertensive patients differed from controls, but not from normotensive patients. For rs10887800 SNP, the differences in the G allele frequencies were observed in hypertensive patients with stroke, with 66% of patients being GG homozygotes. To confirm observed association we later genotyped 130 stroke patients without diabetes. The OR for risk allele was 1.79 (95% CI 1.33–2.41). In conclusion, the renalase gene polymorphism was associated with hypertension in type 2 diabetes patients. The most interesting result is a strong association of the rs10887800 polymorphism with stroke in patients with and without diabetes. The G allele of this polymorphism might thus be useful in identifying diabetes patients at increased risk of stroke

Energy- and flux-budget (EFB) turbulence closure model for the stably stratified flows. Part I: Steady-state, homogeneous regimes

We propose a new turbulence closure model based on the budget equations for the key second moments: turbulent kinetic and potential energies: TKE and TPE (comprising the turbulent total energy: TTE = TKE + TPE) and vertical turbulent fluxes of momentum and buoyancy (proportional to potential temperature). Besides the concept of TTE, we take into account the non-gradient correction to the traditional buoyancy flux formulation. The proposed model grants the existence of turbulence at any gradient Richardson number, Ri. Instead of its critical value separating - as usually assumed - the turbulent and the laminar regimes, it reveals a transition interval, 0.1< Ri <1, which separates two regimes of essentially different nature but both turbulent: strong turbulence at Ri<<1; and weak turbulence, capable of transporting momentum but much less efficient in transporting heat, at Ri>1. Predictions from this model are consistent with available data from atmospheric and lab experiments, direct numerical simulation (DNS) and large-eddy simulation (LES).Comment: 40 pages, 6 figures, Boundary-layer Meteorology, resubmitted, revised versio

Getting into hot water:sick guppies frequent warmer thermal conditions

Ectotherms depend on the environmental temperature for thermoregulation and exploit thermal regimes that optimise physiological functioning. They may also frequent warmer conditions to up-regulate their immune response against parasite infection and/or impede parasite development. This adaptive response, known as ‘behavioural fever’, has been documented in various taxa including insects, reptiles and fish, but only in response to endoparasite infections. Here, a choice chamber experiment was used to investigate the thermal preferences of a tropical freshwater fish, the Trinidadian guppy (Poecilia reticulata), when infected with a common helminth ectoparasite Gyrodactylus turnbulli, in female-only and mixed-sex shoals. The temperature tolerance of G. turnbulli was also investigated by monitoring parasite population trajectories on guppies maintained at a continuous 18, 24 or 32 °C. Regardless of shoal composition, infected fish frequented the 32 °C choice chamber more often than when uninfected, significantly increasing their mean temperature preference. Parasites maintained continuously at 32 °C decreased to extinction within 3 days, whereas mean parasite abundance increased on hosts incubated at 18 and 24 °C. We show for the first time that gyrodactylid-infected fish have a preference for warmer waters and speculate that sick fish exploit the upper thermal tolerances of their parasites to self medicate