Biliverdin-based egg coloration is enhanced by carotenoid supplementation

Avian eggshell color is remarkably variable among and within species and its possible function has long been controversial. Female birds use biliverdin pigment to color their eggs blue and green. Although evidence is accumulating that blue-green eggshell coloration is costly to produce, the exact mechanisms underlying its expression are little studied. Biliverdin pigment is involved in important maintenance functions such as immune and antioxidant defenses and shows similar properties to carotenoid pigments. Carotenoids play a role as immunoenhancers and have the potential to ameliorate the impact of oxidative processes, although their antioxidant function could be minor for some bird species. Important life-history components can be limited by carotenoid availability, including sexual displays and fecundity. Here we explored if biliverdin-based eggshell pigmentation was affected by carotenoid availability in a seabird, by performing a carotenoid supplementation experiment in female blue-footed boobies (Sula nebouxii) after laying their first egg. In this species, blue eggshell color is associated with incubation patterns, and carotenoid availability affects the crucial trade-off between female foot ornamentation and fecundity. We found that under natural conditions, there was a decline in eggshell color with laying order, suggesting pigment limitation for females. However, carotenoid-supplemented females had enhanced second egg coloration compared to controls, and the color increase was independent of their previous pigment allocation to the first egg. Our results suggest that biliverdin-based eggshell coloration is costly to produce and can be alleviated by current carotenoid availability.     

Validating an evidence-based, self-rated fall risk questionnaire (FRQ) for older adults

Background

Falls are a common, serious, and often unrecognized problem facing older adults. The objective of this study was to provide an initial clinical and statistical validation for a public health strategy of fall risk self-assessment by older adults using a Fall Risk Questionnaire (FRQ).

Methods

Adults age 65 + (n = 40) were recruited at a Los Angeles Veterans Affairs (VA) medical facility and at a local assisted living facility. Participants completed the FRQ self-assessment and results were compared to a “gold standard” of a clinical evaluation of risks using the American/British Geriatrics Society guidelines to assess independent predictors of falls: history of previous falls, fear of falling, gait/balance, muscle weakness, incontinence, sensation and proprioception, depression, vision, and medications. For the comparison, we used an iterative statistical approach, weighing items based on relative risk.

Results

There was strong agreement between the FRQ and clinical evaluation (kappa = .875, p < .0001). Individual item kappa values ranged from .305-.832. After dropping one FRQ item (vision risk) because of inadequate agreement with the clinical evaluation (kappa = .139, p = .321), the final FRQ had good concurrent validity.

Conclusions

The FRQ goes beyond existing screening tools in that it is based on both evidence and clinical acceptability and has been initially validated with clinical examination data. A larger validation with longitudinal follow-up should determine the actual strength of the FRQ in predicting future falls.     

Thermoplastic Starch (TPS)/Polylactic Acid (PLA) Blending Methodologies: A Review

Polylactic acid (PLA) and thermoplastic starch (TPS) are biodegradable polymers of biological origin, and the mixture of these polymers has been studied due to the desirable mechanical properties of PLA and the low processing cost of TPS. However, the TPS/PLA combination is thermodynamically immiscible due to the poor interfacial interaction between the hydrophilic starch granules and the hydrophobic PLA. To overcome these limitations, researchers studied the modification, processing, and properties of the mixtures as a strategy to increase the compatibility between phases. This review highlights recent developments, current results, and trends in the field of TPS/PLA-based compounds during the last two decades, with the main focus of improving the adhesion between the two components. The TPS/PLA blends were classified as plasticized, compatible, reinforced and with nanocomposites. This article presents, based on published research, TPS/PLA combinations, considering different methods with significant improvements in mechanical properties, with promising developments for applications in food packaging and biomedicine.

     

Hydrothermal carbonization of biomass and waste: A review

Environmental Chemistry Letters - The replacement of traditional and non-renewable resources by shifting towards renewable-based strategies is a&nbsp;strategy implemented by the European Union...     

Essential and non-essential trace element concentrations in muscle and liver of a pregnant Munk’s pygmy devil ray (Mobula munkiana) and its embryo

During gestation, essential and non-essential trace elements are transferred from the pregnant females to embryos. This study aimed to determine and compare the concentrations of seven essential trace elements (Fe, Zn, Se, Cu, Mn, Cr, Co) and six non-essential trace elements (As, Cd, V, U, Tl, Ag) in the muscle and the liver of a Munk’s pygmy devil ray pregnant female, Mobula munkiana, and its embryo. Transfer evidence of essential and non-essential trace elements was detected in M. munkiana tissues. Arsenic was found in elevated concentrations in the pregnant female and the embryo tissues. Elevated levels of Cd, V, U, and Ag were found in the pregnant female liver, but were minimal in the embryo tissue. This is the first study to investigate maternal transfer of essential and non-essential trace elements in these species and their reproductive strategy.

     

Aspects of population ecology in two populations of fiddler crabs, <Emphasis Type="Italic">Uca pugnax</Emphasis>

Fiddler crabs, Uca pugnax, were collected from a highly contaminated site and a relatively clean site, both in New Jersey to determine if and how environments with varying levels of pollutants may impact aspects of population biology including individual size, morphology (major cheliped size), population density, fecundity, recruitment and survivorship of early benthic phases. Crabs from the highly contaminated site were significantly larger in size, but had lower population density, lower recruitment, reduced reproductive season and lower survivorship of early benthic phases. Our study suggests that contamination may play a role in population ecology of U. pugnax. This study also determined that the reproductive season for U. pugnax in New Jersey is much longer than reported in the literature and could potentially be impacted by global climate change.     

Important areas at sea for adult loggerhead sea turtles in the Mediterranean Sea: satellite tracking corroborates findings from potentially biased sources

Sea turtle populations worldwide suffer from reduced survival of immatures and adults due to fishery bycatch. Unfortunately, information about the whereabouts of turtles outside the breeding habitat is scarce in most areas, hampering the development of spatially explicit conservation plans. In the Mediterranean, recoveries of adult females flipper-tagged on nesting beaches suggest that the Adriatic Sea and Gulf of Gabès are important foraging areas for adults, but such information could be heavily biased (observing and reporting bias). In order to obtain unbiased data, we satellite-tracked seven loggerhead sea turtles after they completed nesting in the largest known Mediterranean rookery (Bay of Laganas, Zakynthos, Greece). Three females settled in the north Adriatic Sea, one in the south Adriatic Sea and two in the Gulf of Gabès area at the completion of their post-nesting migrations (one individual did not occupy a distinct foraging area). The concordance of tracking results with information from recoveries of flipper-tagged turtles suggests that the north Adriatic Sea and the Gulf of Gabès represent key areas for female adult Mediterranean loggerhead sea turtles.     

The influence of successional processes and disturbance on the structure of Tsuga canadensis forests

Old-growth forests are valuable sources of ecological, conservation, and management information, yet these ecosystems have received little study in New England, due in large part to their regional scarcity. To increase our understanding of the structures and processes common in these rare forests, we studied the abundance of downed coarse woody debris (CWD) and snags and live-tree size-class distributions in 16 old-growth hemlock forests in western Massachusetts. Old-growth stands were compared with eight adjacent second-growth hemlock forests to gain a better understanding of the structural differences between these two classes of forests resulting from contrasting histories. In addition, we used stand-level dendroecological reconstructions to investigate the linkages between disturbance history and old-growth forest structure using an information-theoretic model selection framework. Old-growth stands exhibit a much higher degree of structural complexity than second-growth forests. In particular, old-growth stands had larger overstory trees and greater volumes of downed coarse woody debris (135.2 vs. 33.2 m3/ha) and snags (21.2 vs. 10.7 m3/ha). Second-growth stands were characterized by either skewed unimodal or reverse-J shaped diameter distributions, while old-growth forests contained bell-shaped, skewed unimodal, rotated sigmoid, and reverse J-shaped distributions. The variation in structural attributes among old-growth stands, particularly the abundance of downed CWD, was closely related to disturbance history. In particular, old-growth stands experiencing moderate levels of canopy disturbance during the last century (1930s and 1980s) had greater accumulations of CWD, highlighting the importance of gap-scale disturbances in shaping the long-term development and structural characteristics of old-growth forests. These findings are important for the development of natural disturbance-based silvicultural systems that may be used to restore important forest characteristics lacking in New England second-growth stands by integrating structural legacies of disturbance (e.g., downed CWD) and resultant tree-size distribution patterns. This silvicultural approach would emulate the often episodic nature of CWD recruitment within old-growth forests.     

Nutrient pathways and their susceptibility to past and future change in the Eurasian Arctic Ocean

Climate change is altering nutrient cycling within the Arctic Ocean, having knock-on effects to Arctic ecosystems. Primary production in the Arctic is principally nitrogen-limited, particularly in the western Pacific-dominated regions where denitrification exacerbates nitrogen loss. The nutrient status of the eastern Eurasian Arctic remains under debate. In the Barents Sea, primary production has increased by 88% since 1998. To support this rapid increase in productivity, either the standing stock of nutrients has been depleted, or the external nutrient supply has increased. Atlantic water inflow, enhanced mixing, benthic nitrogen cycling, and land–ocean interaction have the potential to alter the nutrient supply through addition, dilution or removal. Here we use new datasets from the Changing Arctic Ocean program alongside historical datasets to assess how nitrate and phosphate concentrations may be changing in response to these processes. We highlight how nutrient dynamics may continue to change, why this is important for regional and international policy-making and suggest relevant research priorities for the future.Supplementary InformationThe online version contains supplementary material available at 10.1007/s13280-021-01673-0.