Intersections of Poverty, Geography, and Custodial Grandparent Caregiving in Appalachia

The purpose of this study is to compare the incidence of custodial grandparenting in Central Appalachia to other areas in Appalachia and the rest of the U.S., to explore how recent economic changes have affected poverty rates of custodial grandparents in all of these areas, and to explore what influences the probability of custodial grandparenting. We hypothesize that the recent economic upheaval of the Great Recession has pressured many families to rely on grandparents to provide care for their grandchildren and that these trends are particularly evident in the Appalachian region due to longstanding historical trends and unique cultural factors. Three year summary data from the American Community Survey (ACS) was used to compare rates of grandparent caregiving along with poverty, children living in grandparent only households, and other indicators of poverty and economic distress both between regions and across three different time periods (2005-07, 2008-10, and 2011-13). We then developed at logistic regression model using the ACS individual level data (Public Use MicroData) for 2009-13 to estimate the probability of caregiving status among grandparents living with grandchildren in each Appalachian region compared to the entire United States. Grandparents living with grandchildren in Central Appalachia had more than double the odds of being the primary caregiver when compared to the rest of the U.S. when controlling for demographics, poverty, gender, race, age, and education. While grandparents can provide an important resource for these families, advocates and state level policy makers need to be aware of the potential downstream costs to children and older adults over time and consider how to better support these Appalachian grandfamilies

Asplenium bird's nest ferns in rainforest canopies are climate-contingent refuges for frogs

Epiphytes are important for canopy dwelling organisms because they provide a cool and moist microhabitat in the relatively hot and dry canopy. Here we examine whether epiphytic Asplenium ferns act as important habitats for arboreal frogs. We conducted extensive fern and habitat surveys for frogs in the Philippines, and complimented these surveys with roaming day and night canopy surveys to identify the full extent of habitat use across the vertical strata. We artificially dried ferns of various sizes to identify relationships between water and temperature buffering. Ferns are the preferred diurnal microhabitat and breeding habitat for arboreal frogs. A strong positive relationship exists between fern size and frog usage and abundance. Our drying experiments show that large ferns buffer maximum temperatures and reduce variability in temperatures, and buffering is directly linked to their hydration. Frogs are likely using large ferns for their moist, cool, environments for breeding and daytime retreat, which supports the buffered microhabitat hypothesis—these plants promote species coexistence through habitat creation and amelioration of physical stress. However, drying experiments suggest that this buffering is contingent on regular rainfall. Altered rainfall regimes could lead to the unexpected loss of the functional capacity of these important fern habitats

Evolutionary predictions for a parasite metapopulation: Modelling salmon louse resistance to pest controls in aquaculture

publishedVersio

A metapopulation model reveals connectivity-driven hotspots in treatment resistance evolution in a marine parasite

In salmon aquaculture, the sustainable management of salmon lice (Lepeophtheirus salmonis) is limited by the adaptive capacity of the parasite. This is evident in the repeated evolution of pesticide resistance in the salmon louse population. To better prepare for resistance, we constructed a numerical metapopulation model that predicts the evolutionary dynamics of lice across an interconnected farm network. This model integrates within-farm population dynamics and between-farm louse dispersal, the latter using outputs from a state-of-the-art particle-tracking model. Distinct from previous metapopulation models, it also simulates spatial and temporal genetic variation arising from selection. The model was parameterized to simulate the evolution of resistance to the pesticide azamethiphos on farms in southern Norway. It successfully reproduced the rapid (within 10 years) evolution of azamethiphos resistance following extensive delousing treatments. It also identified strong spatial patterns in resistance, with regions of high farm connectivity being potential hotspots of louse adaptation. Rates of infestation and evolution were significantly reduced when highly connected farms were excluded from the simulation, compared to when low-connectivity or random sites were excluded. This model can be a valuable tool for coordinating pest management at a regional scale, in a way that slows or prevents the spread of resistance.A metapopulation model reveals connectivity-driven hotspots in treatment resistance evolution in a marine parasitepublishedVersio

Anywhere but here: local conditions motivate dispersal in Daphnia

Dispersal is fundamental to population dynamics. However, it is increasingly apparent that, despite most models treating dispersal as a constant, many organisms make dispersal decisions based upon information gathered from the environment. Ideally, organisms would make fully informed decisions, with knowledge of both intra-patch conditions (conditions in their current location) and extra-patch conditions (conditions in alternative locations). Acquiring information is energetically costly, however, and extra-patch information will typically be costlier to obtain than intra-patch information. As a consequence, theory suggests that organisms will often make partially informed dispersal decisions, utilising intra-patch information only. We test this proposition in an experimental two-patch system using populations of the aquatic crustacean, Daphnia carinata. We manipulated conditions (food availability) in the population’s home patch, and in its alternative patch. We found that D. carinata made use of intra-patch information (resource availability in the home patch induced a 10-fold increase in dispersal probability) but either ignored or were incapable of using of extra-patch information (resource availability in the alternative patch did not affect dispersal probability). We also observed a small apparent increase in dispersal in replicates with higher population densities, but this effect was smaller than the effect of resource constraint, and not found to be significant. Our work highlights the considerable influence that information can have on dispersal probability, but also that dispersal decisions will often be made in only a partially informed manner. The magnitude of the response we observed also adds to the growing chorus that condition-dependence may be a significant driver of variation in dispersal

Peripheral isolates as sources of adaptive diversity under climate change

As climate change progresses, there is increasing focus on the possibility of using targeted gene flow (TGF, the movement of pre-adapted individuals into declining populations) as a management tool. Targeted gene flow is a relatively cheap, low-risk management option, and will almost certainly come into increased use over the coming decades. Before such action can be taken, however, we need to know where to find pre-adapted individuals. We argue that, for many species, the obvious place to look for this diversity is in peripheral isolates: isolated populations at the current edges of a species' range. Both evolutionary and ecological considerations suggest that the bulk of a species' adaptive variation may be contained in the total set of these peripheral isolates. Moreover, by exploring both evolutionary and ecological perspectives it becomes clear that we should be able to assess the potential value of each isolate using remotely sensed data and three measurable axes of variation in patch traits: population size, connectivity, and climatic environment. Locating the “sweet spot” in this trait space, however, remains a challenge. Throughout, we illustrate these ideas using Australia's Wet Tropics rainforests as a model system.We thank the Australian Research Council for funding this work (DP1094646, FL110100104, DP130100318, FT160100198); the Tropical Landscapes Joint Venture (a collaboration between CSIRO and JCU) for support to SM and JL; and the Wet Tropics Management Authority for support to SM

Review of Potential Wind Tunnel Balance Technologies

This manuscript reviews design, manufacture, materials, sensors, and data acquisition technologies that may benefit wind tunnel balances for the aerospace research community. Current state-of-the-art practices are used as the benchmark to consider advancements driven by researcher and facility needs. Additive manufacturing is highlighted as a promising alternative technology to conventional fabrication and has the potential to reduce both the cost and time required to manufacture force balances. Material alternatives to maraging steels are reviewed. Sensor technologies including piezoresistive, piezoelectric, surface acoustic wave, and fiber optic are compared to traditional foil based gages to highlight unique opportunities and shared challenges for implementation in wind tunnel environments. Finally, data acquisition systems that could be integrated into force balances are highlighted as a way to simplify the user experience and improve data quality. In summary, a rank ordering is provided to support strategic investment in exploring the technologies reviewed in this manuscript

Pre-emptive Quality Control of a Misfolded Membrane Protein by Ribosome-Driven Effects.

Cells possess multiple mechanisms that protect against the accumulation of toxic aggregation-prone proteins. Here, we identify a pre-emptive pathway that reduces synthesis of membrane proteins that have failed to properly assemble in the endoplasmic reticulum (ER). We show that loss of the ER membrane complex (EMC) or mutation of the Sec61 translocon causes reduced synthesis of misfolded forms of the yeast ABC transporter Yor1. Synthesis defects are rescued by various ribosomal mutations, as well as by reducing cellular ribosome abundance. Genetic and biochemical evidence point to a ribosome-associated quality-control pathway triggered by ribosome collisions when membrane domain insertion and/or folding fails. In support of this model, translation initiation also contributes to synthesis defects, likely by modulating ribosome abundance on the message. Examination of translation efficiency across the yeast membrane proteome revealed that polytopic membrane proteins have relatively low ribosome abundance, providing evidence for translational tuning to balance protein synthesis and folding. We propose that by modulating translation rates of poorly folded proteins, cells can pre-emptively protect themselves from potentially toxic aberrant transmembrane proteins

Response to Letter to the Editor from Richard Dorin:Dynamic pituitary-adrenal interactions in the critically ill after cardiac surgery

Diabetes mellitus: pathophysiological changes and therap

Dynamic pituitary-adrenal interactions in the critically ill after cardiac surgery

Context: Patients with critical illness are thought to be at risk of adrenal insufficiency. There are no models of dynamic hypothalamic-pituitary-adrenal (HPA) axis function in this group of patients and thus current methods of diagnosis are based on aggregated, static models.Objective: To characterize the secretory dynamics of the HPA axis in the critically ill (CI) after cardiac surgery.Design: Mathematical modeling of cohorts.Setting: Cardiac critical care unit.Patients: 20 male patients CI at least 48 hours after cardiac surgery and 19 healthy (H) male volunteers. Interventions: None.Main Outcome Measures: Measures of hormone secretory dynamics were generated from serum adrenocorticotrophic hormone (ACTH) sampled every hour and total cortisol every 10 min for 24 h.Results: All CI patients had pulsatile ACTH and cortisol profiles. CI patients had similar ACTH secretion (1036.4 [737.6] pg/mL/24 h) compared to the H volunteers (1502.3 [1152.2] pg/mL/24 h; P=.20), but increased cortisol secretion (CI: 14 447.0 [5709.3] vs H: 5915.5 [1686.7)] nmol/L/24 h; P<.0001). This increase in cortisol was due to nonpulsatile (CI: 9253.4 [3348.8] vs H: 960 [589.0] nmol/L/24 h, P<.0001), rather than pulsatile cortisol secretion (CI: 5193.1 [3018.5] vs H: 4955.1 [1753.6] nmol/L/24 h; P=.43). Seven (35%) of the 20 CI patients had cortisol pulse nadirs below the current international guideline threshold for critical illness-related corticosteroid insufficiency, but an overall secretion that would not be considered deficient.Conclusions: This study supports the premise that current tests of HPA axis function are unhelpful in the diagnosis of adrenal insufficiency in the CI. The reduced ACTH and increase in nonpulsatile cortisol secretion imply that the secretion of cortisol is driven by factors outside the HPA axis in critical illness.Diabetes mellitus: pathophysiological changes and therap