Halide Perovskites Breathe Too: The Iodide-Iodine Equilibrium and Self-Doping in CsSnI.

The response of an oxide crystal to the atmosphere can be personified as breathing-a dynamic equilibrium between O gas and O anions in the solid. We characterize the analogous defect reaction in an iodide double-perovskite semiconductor, CsSnI. Here, I gas is released from the crystal at room temperature, forming iodine vacancies.

Using stable isotopes in hummingbird breath to estimate reliance on supplemental feeders.

Understanding the ecological consequences of supplemental feeding to both hummingbirds and the plants they pollinate is complicated by logistical challenges associated with assessing relative dietary resource use with commonly applied observational methods. Here, we describe the results of research conducted to assess the relative use of feeder and flower nectar by Broad-tailed () and Rufous hummingbirds () using two distinct methodological variations to measure the δC values of exhaled CO. Because of the relatively quick time in which both species switch from exogenous to endogenous resources to fuel metabolism, our experiment allowed us to assess resource use at two timescales.

Quasi-One-Dimensional Metallicity in Compressed CsSnI.

Low-dimensional metal halides exhibit strong structural and electronic anisotropies, making them candidates for accessing unusual electronic properties. Here, we demonstrate pressure-induced quasi-one-dimensional (quasi-1D) metallicity in δ-CsSnI. With the application of pressure up to 40 GPa, the initially insulating δ-CsSnI transforms to a metallic state.

Cesium-mediated electron redistribution and electron-electron interaction in high-pressure metallic CsPbI.

Electron-phonon coupling was believed to govern the carrier transport in halide perovskites and related phases. Here we demonstrate that electron-electron interaction enhanced by Cs-involved electron redistribution plays a direct and prominent role in the low-temperature electrical transport of compressed CsPbI and renders Fermi liquid (FL)-like behavior. By compressing δ-CsPbI to 80 GPa, an insulator-semimetal-metal transition occurs, concomitant with the completion of a slow structural transition from the one-dimensional Pnma (δ) phase to a three-dimensional Pmn2 (ε) phase.

Tuning Defects in a Halide Double Perovskite with Pressure.

Dopant defects in semiconductors can trap charge carriers or ionize to produce charge carriers─playing a critical role in electronic transport. Halide perovskites are a technologically important semiconductor family with a large pressure response. Yet, to our knowledge, the effect of high pressures on defects in halide perovskites has not been experimentally investigated.

Charge Reservoirs in an Expanded Halide Perovskite Analog: Enhancing High-Pressure Conductivity through Redox-Active Molecules.

As halide perovskites and their derivatives are being developed for numerous optoelectronic applications, controlling their electronic doping remains a fundamental challenge. Herein, we describe a novel strategy of using redox-active organic molecules as stoichiometric electron acceptors. The cavities in the new expanded perovskite analogs (dmpz)[Sn X ], (X=Br (1Br) and I (1I)) are occupied by dmpz (N,N'-dimethylpyrazinium), with the LUMOs lying ca.

Perspectives on Individual Animal Identification from Biology and Computer Vision.

Identifying individual animals is crucial for many biological investigations. In response to some of the limitations of current identification methods, new automated computer vision approaches have emerged with strong performance. Here, we review current advances of computer vision identification techniques to provide both computer scientists and biologists with an overview of the available tools and discuss their applications.

Doubling the Stakes: The Promise of Halide Double Perovskites.

When the stakes are doubled in a wager, a player must correctly place two consecutive bets to win, but the payout is larger. Similarly, two B sites in combination dictate the properties of A BB'X (A=monocation, X=halide) double perovskites. Correctly picking two B sites is more challenging than picking just one, as in the A B X single perovskites, but the options are greater and, we believe, the rewards are higher when the stakes are doubled.

Controlled experiments to explore the use of a multi-tissue approach to characterizing stress in wild-caught Pacific halibut ().

The integration of multiple tissues in physiological and ecological analyses can enhance methodological approaches, increase applications for data and extend interpretation of results. Previous investigations of the stress response in fish have focused primarily on cortisol levels in a single matrix-blood plasma-which confines interpretations of cortisol levels to a short temporal frame. Epidermal mucus has been proposed as an alternative or complement to plasma that may provide a view to cortisol levels over a different temporal window allowing comparative assessment.

Preserving a robust CsPbI perovskite phase via pressure-directed octahedral tilt.

Functional CsPbI perovskite phases are not stable at ambient conditions and spontaneously convert to a non-perovskite δ phase, limiting their applications as solar cell materials. We demonstrate the preservation of a black CsPbI perovskite structure to room temperature by subjecting the δ phase to pressures of 0.1 - 0.

A comprehensive description of oocyte developmental stages in Pacific halibut, Hippoglossus stenolepis.

Accurate characterization of oocyte development is essential to understanding foundational aspects of reproductive biology and successful management of Pacific halibut (Hippoglossus stenolepis). Here this study provides complete histological descriptions for eight oocyte developmental stages in addition to postovulatory follicles and demonstrates the potential for oocyte size frequency distribution to act as a proxy for ovarian developmental stage and future maturity assessments. Importantly, it provides the first histological evidence that Pacific halibut have a group-synchronous ovarian developmental pattern with determinate fecundity and support for their batch-spawning strategy.

Exploring sample cross-contamination in fish epidermal mucus.

Cross-contamination of epidermal mucus was assessed at three sampling locations on the bodies of Pacific halibut Hippoglossus stenolepis by inducing contact between fish coated with labelled synthetic mucus and non-treated fish. Results indicate a positive relationship between sampling site exposure and sample contamination and that mucous sample cross-contamination can be mitigated by sampling in a location protected from external contact.

Ichthyophonus in sport-caught groundfishes from southcentral Alaska.

This report of Ichthyophonus in common sport-caught fishes throughout the marine waters of southcentral Alaska represents the first documentation of natural Ichthyophonus infections in lingcod Ophiodon elongates and yelloweye rockfish Sebastes ruberrimus. In addition, the known geographic range of Ichthyophonus in black rockfish S. melanops has been expanded northward to include southcentral Alaska.

Evaluating the capabilities model of dementia care: a non-randomized controlled trial exploring resident quality of life and care staff attitudes and experiences.

Background: This 12 month, Australian study sought to compare the Capabilities Model of Dementia Care (CMDC) with usual long-term care (LTC), in terms of (1) the effectiveness of the CMDC in assisting care staff to improve Quality Of Life (QOL) for older people with dementia; and (2) whether implementation of the CMDC improved staff attitudes towards, and experiences of working and caring for the person with dementia.

Methods: A single blind, non-randomized controlled trial design, involving CMDC intervention group (three facilities) and a comparison usual LTC practice control group (one facility), was conducted from August 2010 to September 2011. Eighty-one staff members and 48 family members of a person with dementia were recruited from these four LTC facilities.

Native mass spectrometry and ion mobility characterize the orange carotenoid protein functional domains.

Orange Carotenoid Protein (OCP) plays a unique role in protecting many cyanobacteria from light-induced damage. The active form of OCP is directly involved in energy dissipation by binding to the phycobilisome (PBS), the major light-harvesting complex in cyanobacteria. There are two structural modules in OCP, an N-terminal domain (NTD), and a C-terminal domain (CTD), which play different functional roles during the OCP-PBS quenching cycle.

Dramatic Domain Rearrangements of the Cyanobacterial Orange Carotenoid Protein upon Photoactivation.

Photosynthetic cyanobacteria make important contributions to global carbon and nitrogen budgets. A protein known as the orange carotenoid protein (OCP) protects the photosynthetic apparatus from damage by dissipating excess energy absorbed by the phycobilisome, the major light-harvesting complex in many cyanobacteria. OCP binds one carotenoid pigment, but the color of this pigment depends on conditions.

Variability in the routing of dietary proteins and lipids to consumer tissues influences tissue-specific isotopic discrimination.

Rationale: The eco-physiological mechanisms that govern the incorporation and routing of macronutrients from dietary sources into consumer tissues determine the efficacy of stable isotope analysis (SIA) for studying animal foraging ecology. We document how changes in the relative amounts of dietary proteins and lipids affect the metabolic routing of these macronutrients and the consequent effects on tissue-specific discrimination factors in domestic mice using SIA. We also examine the effects of dietary macromolecular content on a commonly used methodological approach: lipid extraction of potential food sources.

Mass spectrometry footprinting reveals the structural rearrangements of cyanobacterial orange carotenoid protein upon light activation.

The orange carotenoid protein (OCP), a member of the family of blue light photoactive proteins, is required for efficient photoprotection in many cyanobacteria. Photoexcitation of the carotenoid in the OCP results in structural changes within the chromophore and the protein to give an active red form of OCP that is required for phycobilisome binding and consequent fluorescence quenching. We characterized the light-dependent structural changes by mass spectrometry-based carboxyl footprinting and found that an α helix in the N-terminal extension of OCP plays a key role in this photoactivation process.

Amino acid δ13C analysis shows flexibility in the routing of dietary protein and lipids to the tissue of an omnivore.

Stable-isotope analysis (SIA) has revolutionized animal ecology by providing time-integrated estimates of the use of resources and/or habitats. SIA is based on the premise that the isotopic composition of a consumer's tissues originates from its food, but is offset by trophic-discrimination (enrichment) factors controlled by metabolic processes associated with the assimilation of nutrients and the biosynthesis of tissues. Laboratory preparation protocols dictate that tissues both of consumers and of their potential prey be lipid-extracted prior to analysis, because (1) lipids have carbon isotope (δ(13)C) values that are lower by approximately 3-8‰ than associated proteins and (2) amino acids in consumers' proteinaceous tissues are assumed to be completely routed from dietary protein.

Environmental and physiological influences to isotopic ratios of N and protein status in a Montane ungulate in winter.

Winter severity can influence large herbivore populations through a reduction in maternal proteins available for reproduction. Nitrogen (N) isotopes in blood fractions can be used to track the use of body proteins in northern and montane ungulates. We studied 113 adult female caribou for 13 years throughout a series of severe winters that reduced population size and offspring mass.

An experimental exploration of the incorporation of hydrogen isotopes from dietary sources into avian tissues.

The analysis of hydrogen stable isotopes (δD) is a potentially powerful tool for studying animal ecology. Unlike other stable isotopes used in ecological research, however, we are less familiar with the physiological processes that influence the incorporation of hydrogen isotopes from dietary resources to animal tissues. Here we present the results of a controlled feeding experiment utilizing Japanese quail (Cortunix japonica) that was designed to: (1) estimate the relative contributions of diet to the δD signatures of blood plasma, red blood cells, intestine, liver, muscle and feathers; (2) investigate possible differences among these same tissues in diet to tissue discrimination; and (3) explore the differences in incorporation dynamics between deuterium ((2)H) and a well-studied isotope, (13)C, for blood plasma solids and red blood cells.

Effects of trophic level and metamorphosis on discrimination of hydrogen isotopes in a plant-herbivore system.

The use of stable isotopes in ecological studies requires that we know the magnitude of discrimination factors between consumer and element sources. The causes of variation in discrimination factors for carbon and nitrogen have been relatively well studied. In contrast, the discrimination factors for hydrogen have rarely been measured.

The influence of drinking water on the deltaD and delta18O values of house sparrow plasma, blood and feathers.

We investigated the relationships between the δdeuterium (δD) and the δ(18)oxygen (δ(18)O) of drinking water and the δD and δ(18)O of blood plasma, red blood cells and feathers in house sparrows (Passer domesticus) fed on diets with identical hydrogen and oxygen isotopic compositions and five isotopically distinct drinking water treatments. We expected and, with only one exception ((18)O in blood plasma), found linear relationships between the δD and δ(18)O values of drinking water and those of bird tissues. The slopes of these relationships, which estimate the percentage contributions of drinking water to the tissue isotopic signatures, were lower than those of previous studies.

Isotopic ecology ten years after a call for more laboratory experiments.

About 10 years ago, reviews of the use of stable isotopes in animal ecology predicted explosive growth in this field and called for laboratory experiments to provide a mechanistic foundation to this growth. They identified four major areas of inquiry: (1) the dynamics of isotopic incorporation, (2) mixing models, (3) the problem of routing, and (4) trophic discrimination factors. Because these areas remain central to isotopic ecology, we use them as organising foci to review the experimental results that isotopic ecologists have collected in the intervening 10 years since the call for laboratory experiments.

Dietary protein influences the rate of 15N incorporation in blood cells and plasma of Yellow-vented bulbuls (Pycnonotus xanthopygos).

The rate at which an animal's tissues incorporate the isotopic composition of food determines the time window during which ecologists can discern diet changes. We investigated the effect of protein content in the diet on the incorporation rate of (15)N into the plasma proteins and blood cells of Yellow-vented bulbuls (Pycnonotus xanthopygos). Using model comparison analyses, we found that one-compartment models described incorporation data better than two-compartment models.