The Bering Strait was flooded 10,000 years before the Last Glacial Maximum.

The cyclic growth and decay of continental ice sheets can be reconstructed from the history of global sea level. Sea level is relatively well constrained for the Last Glacial Maximum (LGM, 26,500 to 19,000 y ago, 26.5 to 19 ka) and the ensuing deglaciation. However, sea-level estimates for the period of ice-sheet growth before the LGM vary by > 60 m, an uncertainty comparable to the sea-level equivalent of the contemporary Antarctic Ice Sheet. Here, we constrain sea level prior to the LGM by reconstructing the flooding history of the shallow Bering Strait since 46 ka. Using a geochemical proxy of Pacific nutrient input to the Arctic Ocean, we find that the Bering Strait was flooded from the beginning of our records at 46 ka until [Formula: see text] ka. To match this flooding history, our sea-level model requires an ice history in which over 50% of the LGM's global peak ice volume grew after 46 ka. This finding implies that global ice volume and climate were not linearly coupled during the last ice age, with implications for the controls on each. Moreover, our results shorten the time window between the opening of the Bering Land Bridge and the arrival of humans in the Americas.

Colour vision in stomatopod crustaceans.

The stomatopod crustaceans, or mantis shrimps, are colourful marine invertebrate predators. Their unusual compound eyes have dorsal and ventral regions resembling typical crustacean apposition designs separated by a unique region called the midband that consists of from two to six parallel rows of ommatidia. In species with six-row midbands, the dorsal four rows are themselves uniquely specialized for colour analysis. Rhabdoms of ommatidia in these rows are longitudinally divided into three distinct regions: an apical ultraviolet (UV) receptor, a shorter-wavelength middle tier receptor and a longer-wavelength proximal tier receptor. Each of the total of 12 photoreceptors has a different spectral sensitivity, potentially contributing to a colour-vision system with 12 channels. Mantis shrimps can discriminate both human-visible and UV colours, but with limited precision compared to other colour-vision systems. Here, we review the structure and function of stomatopod colour vision, examining the types of receptors present in a species, the spectral tuning of photoreceptors both within and across species, the neural analysis of colour and the genetics underlying the multiple visual pigments used for colour vision. Even today, after many decades of research into the colour vision of stomatopods, much of its operation and its use in nature remain a mystery. This article is part of the theme issue 'Understanding colour vision: molecular, physiological, neuronal and behavioural studies in arthropods'.

Sexual intimacy and aging: An integrative framework to promote intimacy resilience in couple therapy.

In our work at the Intimacies Project at The Ackerman Institute for the Family we became aware of a gap in attention about sexuality and aging in the couple and family therapy field. In this article, we provide an integrative framework to guide therapists on how to address problems of sexuality and aging in the therapy room. Starting from considerations about the social context of aging and the self of the therapist, we contend that when normative sexual challenges become entangled with stigma, misconceptions about sexuality, limiting gender narratives, vulnerabilities, and defensive postures, they often result in emotional and sexual shutdowns. Through a combination of the vulnerability cycle with an expansive definition of sexuality, we demonstrate how we deconstruct impasses, disentangle normative quandaries from reactive dynamics, and help couples transform their sexual narratives. We outline how we conduct individual sessions to obtain relational sexual histories, utilize Sensate Focus as a mindful touch exercise, and help partners expand their sexual menus beyond penetration and orgasms. We also describe relational skills that may need to be strengthened to help aging couples deal with the ebb and flow of intimacy, sustaining resilience over time.

Understanding how people with Parkinson's disease and their relatives approach advance care planning.

PURPOSE: Advance care planning gives individuals with capacity the option of planning for their future, and anticipating future decision-making about their treatment or care should they then lose capacity. People with Parkinson's disease (PD) may develop significant physical and cognitive problems as the disease progresses, which creates a great need for, but significant challenges to, advance care planning. As a result, we set out to explore the views of people with PD and relatives on planning for the future and advance care planning. METHODS: Qualitative study with semi-structured interviews of thirty-three people with PD and their relatives in the North-East of England. RESULTS: Interviewees with PD were generally not keen to engage with advance care planning in the present, in comparison to the future. Three main themes arose from the data in identifying why this may be the case: (1) 'Awareness'-which included the limited awareness on purpose of advance care planning and Parkinson's disease; (2) 'Uncertainty'-the uncertainty of living with PD and of life; and (3) 'Salience'-the complex decision-making processes that interviewees engaged in, which were highly variable. CONCLUSION: The use of advance care planning in PD is influenced by its perception amongst people with PD and their relatives. Health professionals have an important role in raising the salience of health care planning.

How Do Patients With Parkinson's Disease Approach Advance Care Planning? A UK-Based Mixed Methods Study.

BACKGROUND: Advance Care Planning (ACP) allows people the opportunity to plan for a time when they may lose capacity. The aim of this study was to determine the extent people with Parkinson's disease (PD) were aware of ACP, existing plans they held and to explore their own views, as well as their relatives, on planning for the future. METHODS: This was a sequential explanatory mixed methods study with a postal quantitative survey to establish awareness and engagement with planning for the future; and qualitative semi-structured interviews to explore the views of people with PD and their relatives on ACP and future plans. RESULTS: 104 questionnaires were analyzed. 76% of respondents had not heard of ACP, while 69% expressed an interest in finding out more about ACP. 78% had a will, and 23% had appointed lasting power of attorneys. All interviewees acknowledged engaging in some aspect of planning. Plans were mostly practical as opposed to health-care related. Interviewees expressed a preference for ACP to be carried out by their PD team, at home, and at a time relevant to their condition. CONCLUSION: The awareness and understanding of ACP in people with PD is low. While there is desire to be better informed about ACP, this did not translate into desire to engage in ACP. Health professionals should identify people for whom ACP may serve a positive purpose, and proactively address ACP as a continuum with them, while ensuring awareness is raised about ACP, and there is access for who are interested.

COVID-19 Knowledge and Behavior Change among High School Students in Semi-Rural Georgia.

BACKGROUND: Many schools transitioned online to reduce viral spread and promote social distancing amid the COVID-19 pandemic. Remote learning may impact health behaviors and coping strategies among adolescents, including reduced physical activity and increased screen time. Social media and peers provide information about the pandemic to adolescents and may influence prevention behaviors. This study aims to assess adolescent knowledge and information about COVID-19, determine students' behavior change, and identify sources students turn to for information on the pandemic. METHODS: Students from 2 high schools in semi-rural Georgia participated in a cross-sectional online survey in March 2020 (N = 761). RESULTS: Common sources for COVID-19 news were peers (80%) and social media (58%). Few adolescents (3%) indicated that teenagers were at higher risk of severe illness due to COVID-19. Responses reveal adolescents understand social distancing and many are participating in prevention behaviors, including handwashing (87%) and staying at home as much as possible (87%). Most respondents reported increases in screen time outside of class (82%). CONCLUSIONS: Findings suggest adolescents are obtaining COVID-19 knowledge from various sources, including social media, with varying degrees of implementation of prevention practices. Increases in screen time and reduced physical activity may impact long-term health among adolescents.

Biogeography and ecology of Ostracoda in the U.S. northern Bering, Chukchi, and Beaufort Seas.

Ostracoda (bivalved Crustacea) comprise a significant part of the benthic meiofauna in the Pacific-Arctic region, including more than 50 species, many with identifiable ecological tolerances. These species hold potential as useful indicators of past and future ecosystem changes. In this study, we examined benthic ostracodes from nearly 300 surface sediment samples, >34,000 specimens, from three regions-the northern Bering, Chukchi and Beaufort Seas-to establish species' ecology and distribution. Samples were collected during various sampling programs from 1970 through 2018 on the continental shelves at 20 to ~100m water depth. Ordination analyses using species' relative frequencies identified six species, Normanicythere leioderma, Sarsicytheridea bradii, Paracyprideis pseudopunctillata, Semicytherura complanata, Schizocythere ikeyai, and Munseyella mananensis, as having diagnostic habitat ranges in bottom water temperatures, salinities, sediment substrates and/or food sources. Species relative abundances and distributions can be used to infer past bottom environmental conditions in sediment archives for paleo-reconstructions and to characterize potential changes in Pacific-Arctic ecosystems in future sampling studies. Statistical analyses further showed ostracode assemblages grouped by the summer water masses influencing the area. Offshore-to-nearshore transects of samples across different water masses showed that complex water mass characteristics, such as bottom temperature, productivity, as well as sediment texture, influenced the relative frequencies of ostracode species over small spatial scales. On the larger biogeographic scale, synoptic ordination analyses showed dominant species-N. leioderma (Bering Sea), P. pseudopunctillata (offshore Chukchi and Beaufort Seas), and S. bradii (all regions)-remained fairly constant over recent decades. However, during 2013-2018, northern Pacific species M. mananensis and S. ikeyai increased in abundance by small but significant proportions in the Chukchi Sea region compared to earlier years. It is yet unclear if these assemblage changes signify a meiofaunal response to changing water mass properties and if this trend will continue in the future. Our new ecological data on ostracode species and biogeography suggest these hypotheses can be tested with future benthic monitoring efforts.

Impact of COVID-19 Pandemic on the Mental Health of Students From 2 Semi-Rural High Schools in Georgia.

BACKGROUND: Concerns have been raised about the consequences of the COVID-19 pandemic on the mental health of adolescents during an important developmental and social period in their lives. This study examines the mental health impact of the pandemic on high school students shortly after closure of public schools in spring 2020, and whether this impact varies by sex, race/ethnicity, socioeconomic status (SES), and grade level. METHODS: A cross-sectional, one-time online survey was completed by racial/ethnically and socioeconomically diverse students in 9th through 12th grade at 2 semi-rural Georgia public high schools (N = 761). RESULTS: Overall, almost one-fourth of high school students were extremely or very worried about the pandemic, with higher rates of worry among students who are racial/ethnic minorities, lower SES, female and in older grades. Results indicated a concerning impact on the stress, anxiety, depression, and loneliness that students are feeling, particularly among girls and those in older grades. Students of color and low SES, who are already disproportionately impacted by COVID-19, are also more likely to experience mental health challenges. CONCLUSIONS: Findings highlight important demographic differences of the impact of COVID-19 on the mental health of high school students and have implications for schools with addressing these needs.

Strange eyes, stranger brains: exceptional diversity of optic lobe organization in midwater crustaceans.

Nervous systems across Animalia not only share a common blueprint at the biophysical and molecular level, but even between diverse groups of animals the structure and neuronal organization of several brain regions are strikingly conserved. Despite variation in the morphology and complexity of eyes across malacostracan crustaceans, many studies have shown that the organization of malacostracan optic lobes is highly conserved. Here, we report results of divergent evolution to this 'neural ground pattern' discovered in hyperiid amphipods, a relatively small group of holopelagic malacostracan crustaceans that possess an unusually wide diversity of compound eyes. We show that the structure and organization of hyperiid optic lobes has not only diverged from the malacostracan ground pattern, but is also highly variable between closely related genera. Our findings demonstrate a variety of trade-offs between sensory systems of hyperiids and even within the visual system alone, thus providing evidence that selection has modified individual components of the central nervous system to generate distinct combinations of visual centres in the hyperiid optic lobes. Our results provide new insights into the patterns of brain evolution among animals that live under extreme conditions.

Mantis shrimp identify an object by its shape rather than its color during visual recognition.

Mantis shrimp commonly inhabit seafloor environments with an abundance of visual features including conspecifics, predators, prey and landmarks used for navigation. Although these animals are capable of discriminating color and polarization, it is unknown what specific attributes of a visual object are important during recognition. Here, we show that mantis shrimp of the species Neogonodactylus oerstedii are able to learn the shape of a trained target. Further, when the shape and color of a target that they had been trained to identify were placed in conflict, N. oerstedii tended to choose the target of the trained shape over the target of the trained color. Thus, we conclude that the shape of the target was more salient than its color during recognition by N. oerstedii, suggesting that the shapes of objects, such as landmarks or other animals, are important for their identification by the species.

Visual system characterization of the obligate bat ectoparasite Trichobius frequens (Diptera: Streblidae).

As an obligate ectoparasite of bats, the bat fly Trichobius frequens (Diptera: Streblidae) inhabits the same subterranean environment as their nocturnal bat hosts. In this study, we characterize the macromorphology, optical architecture, rhabdom anatomy, photoreceptor absorbance, and opsin expression of the significantly reduced visual system in T. frequens resulting from evolution in the dark. The eyes develop over a 21-22 day pupal developmental period, with pigmentation appearing on pupal day 11. After eclosion as an adult, T. frequens eyes consist of on average 8 facets, each overlying a fused rhabdom consisting of anywhere from 11 to 18 estimated retinula cells. The dimensions of the facets and fused rhabdoms are similar to those measured in other nocturnal insects. T. frequens eyes are functional as shown by expression of a Rh1 opsin forming a visual pigment with a peak sensitivity to 487 nm, similar to other dipteran Rh1 opsins. Future studies will evaluate how individuals with such reduced capabilities for spatial vision as well as sensitivity still capture enough visual information to use flight to maneuver through dark habitats.

Landmark navigation in a mantis shrimp.

Mantis shrimp commonly occupy burrows in shallow, tropical waters. These habitats are often structurally complex where many potential landmarks are available. Mantis shrimp of the species Neogonodactylus oerstedii return to their burrows between foraging excursions using path integration, a vector-based navigational strategy that is prone to accumulated error. Here, we show that N. oerstedii can navigate using landmarks in parallel with their path integration system, correcting for positional uncertainty generated when navigating using solely path integration. We also report that when the path integration and landmark navigation systems are placed in conflict, N. oerstedii will orientate using either system or even switch systems enroute. How they make the decision to trust one navigational system over another is unclear. These findings add to our understanding of the refined navigational toolkit N. oerstedii relies upon to efficiently navigate back to its burrow, complementing its robust, yet error prone, path integration system with landmark guidance.

Visual metamorphoses in insects and malacostracans: Transitions between an aquatic and terrestrial life.

Arthropods operate in an outrageous diversity of environments. From the deep sea to dense tropical forests, to wide open arctic tundra, they have colonized almost every possible habitat. Within these environments, the presence of light is nearly ubiquitous, varying in intensity, wavelength, and polarization. Light provides critical information about the environment, such as time of day or where food sources may be located. Animals take advantage of this prevalent and informative cue to make behavioral choices. However, the types of choices animals face depend greatly on their environments and needs at any given time. In particular, animals that undergo metamorphosis, with arthropods being the prime example, experience dramatic changes in both behavior and ecology, which in turn may require altering the structure and function of sensory systems such as vision. Amphibiotic organisms maintain aquatic lifestyles as juveniles before transitioning to terrestrial lifestyles as adults. However, light behaves differently in water than in air, resulting in distinct aquatic and terrestrial optical environments. Visual changes in response to these optical differences can occur on multiple levels, from corneal structure down to neural organization. In this review, we summarize examples of alterations in the visual systems of amphibiotic larval and adult insects and malacostracan crustaceans, specifically those attributed to environmental differences between metamorphic phases.

Sensory Ecology: In Sea Snake Vision, One Plus One Makes Three.

Snake genomes encode only two opsins for use in retinal cones, limiting their adaptive flexibility and color vision. Research now shows that, by using alternative opsin alleles, some sea snakes may add a third opsin spectral class to their retinas.

Path integration error and adaptable search behaviors in a mantis shrimp.

Mantis shrimp of the species Neogonodactylus oerstedii occupy small burrows in shallow waters throughout the Caribbean. These animals use path integration, a vector-based navigation strategy, to return to their homes while foraging. Here, we report that path integration in N. oerstedii is prone to error accumulated during outward foraging paths and we describe the search behavior that N. oerstedii employs after it fails to locate its home following the route provided by its path integrator. This search behavior forms continuously expanding, non-oriented loops that are centered near the point of search initiation. The radius of this search is scaled to the animal's positional uncertainty during path integration, improving the effectiveness of the search. The search behaviors exhibited by N. oerstedii bear a striking resemblance to search behaviors in other animals, offering potential avenues for the comparative examination of search behaviors and how they are optimized in disparate taxa.

Exceptional diversity of opsin expression patterns in Neogonodactylus oerstedii (Stomatopoda) retinas.

Stomatopod crustaceans possess some of the most complex animal visual systems, including at least 16 spectrally distinct types of photoreceptive units (e.g., assemblages of photoreceptor cells). Here we fully characterize the set of opsin genes expressed in retinal tissues and determine expression patterns of each in the stomatopod Neogonodactylus oerstedii Using a combination of transcriptome and RACE sequencing, we identified 33 opsin transcripts expressed in each N. oerstedii eye, which are predicted to form 20 long-wavelength-sensitive, 10 middle-wavelength-sensitive, and three UV-sensitive visual pigments. Observed expression patterns of these 33 transcripts were highly unusual in five respects: 1) All long-wavelength and short/middle-wavelength photoreceptive units expressed multiple opsins, while UV photoreceptor cells expressed single opsins; 2) most of the long-wavelength photoreceptive units expressed at least one middle-wavelength-sensitive opsin transcript; 3) the photoreceptors involved in spatial, motion, and polarization vision expressed more transcripts than those involved in color vision; 4) there is a unique opsin transcript that is expressed in all eight of the photoreceptive units devoted to color vision; and 5) expression patterns in the peripheral hemispheres of the eyes suggest visual specializations not previously recognized in stomatopods. Elucidating the expression patterns of all opsin transcripts expressed in the N. oerstedii retina reveals the potential for previously undocumented functional diversity in the already complex stomatopod eye and is a first step toward understanding the functional significance of the unusual abundance of opsins found in many arthropod species' visual systems.

Mantis Shrimp Navigate Home Using Celestial and Idiothetic Path Integration.

Path integration is a robust mechanism that many animals employ to return to specific locations, typically their homes, during navigation. This efficient navigational strategy has never been demonstrated in a fully aquatic animal, where sensory cues used for orientation may differ dramatically from those available above the water's surface. Here, we report that the mantis shrimp, Neogonodactylus oerstedii, uses path integration informed by a hierarchical reliance on the sun, overhead polarization patterns, and idiothetic (internal) orientation cues to return home when foraging, making them the first fully aquatic path-integrating animals yet discovered. We show that mantis shrimp rely on navigational strategies closely resembling those used by insect navigators, opening a new avenue for the investigation of the neural basis of navigation behaviors and the evolution of these strategies in arthropods and potentially other animals as well. VIDEO ABSTRACT.

Optic lobe organization in stomatopod crustacean species possessing different degrees of retinal complexity.

Stomatopod crustaceans possess tripartite compound eyes; upper and lower hemispheres are separated by an equatorial midband of several ommatidial rows. The organization of stomatopod retinas is well established, but their optic lobes have been studied less. We used histological staining, immunolabeling, and fluorescent tracer injections to compare optic lobes in two 6-row midband species, Neogonodactylus oerstedii and Pseudosquilla ciliata, to those in two 2-row midband species, Squilla empusa and Alima pacifica. Compared to the 6-row species, we found structural differences in all optic neuropils in both 2-row species. Photoreceptor axons from 2-row midband ommatidia supply two sets of lamina cartridges; however, conspicuous spaces lacking lamina cartridges are observed in locations corresponding to where the cartridges of the upper four ommatidial rows of 6-row species would exist. The tripartite arrangement and enlarged projections containing fibers associated with the two rows of midband ommatidia can be traced throughout the entire optic lobe. However, 2-row species lack some features of medullar and lobular neuropils in 6-row species. Our results support the hypothesis that 2-row midband species are derived from a 6-row ancestor, and suggest specializations in the medulla and lobula found solely in 6-row species are important for color and polarization analysis.

Chronic kidney disease-mineral bone disorder.

Chronic kidney disease-mineral bone disorder is typically seen in patients with advanced chronic kidney disease. It is managed primarily by renal physicians, but non-renal physicians are also likely to encounter patients undergoing treatment for this condition in both inpatient and outpatient settings so a basic understanding of the principles may be helpful. This article covers the fundamentals of the pathophysiology, diagnosis and treatment of chronic kidney disease-mineral bone disorder.