Climate-driven regime shifts in a mangrove-salt marsh ecotone over the past 250 years.

Climate change is driving the tropicalization of temperate ecosystems by shifting the range edges of numerous species poleward. Over the past few decades, mangroves have rapidly displaced salt marshes near multiple poleward mangrove range limits, including in northeast Florida. It is uncertain whether such mangrove expansions are due to anthropogenic climate change or natural climate variability. We combined historical accounts from books, personal journals, scientific articles, logbooks, photographs, and maps with climate data to show that the current ecotone between mangroves and salt marshes in northeast Florida has shifted between mangrove and salt marsh dominance at least 6 times between the late 1700s and 2017 due to decadal-scale fluctuations in the frequency and intensity of extreme cold events. Model projections of daily minimum temperature from 2000 through 2100 indicate an increase in annual minimum temperature by 0.5 °C/decade. Thus, although recent mangrove range expansion should indeed be placed into a broader historical context of an oscillating system, climate projections suggest that the recent trend may represent a more permanent regime shift due to the effects of climate change

Memory Aging: Deficits, Beliefs, and Interventions

Of all mental faculties, memory is unique. It defines who we are and places our lives on a narrative continuum from birth to death. It helps to structure our days, it guides our daily tasks and goals, and it provides pleasurable interludes as we anticipate the future and recall the past. As a core, defining feature of the self (Birren & Schroots, 2006), memory takes on heightened meaning as we age. In the face of other losses that accumulate with age, memory can serve to preserve our sense of self and place in time. In normal aging, memory loss is minor and relatively inconsequential to functional well-being, other than passing annoyance at not being able to retrieve a name or a location from time to time. In non-normal or pathological aging, as characterized by Alzheimer\u27s disease (AD), the loss of memory is severe and debilitating. In addition to functional disability, people with AD ultimately lose their sense of self. Connections to the past, to current events and relationships, and to what the future holds fade and ultimately disappear. Such a bleak fate for the self continues to spur researchers to look for causes and cures for normal and pathological memory failure. Current cutting-edge research examines the transition from normal to pathological memory aging, with particular emphasis on mild cognitive impairment (MCI) as a transitional phase and as an independent risk factor for AD. Concurrent efforts have focused on developing effective intervention and treatment programs aimed at biological, psychosocial, and cognitive levels. This chapter highlights current research on normative memory change with age, with a focus on self-regulation, self efficacy, and memory maintenance and maximization. We also look at the special contexts of mild cognitive impairment and Alzheimer\u27s disease, and close with an eye toward future directions in theory, research, and intervention

Excision of a Rare Triquetral Body Fracture Nonunion

Aside from the more common dorsal avulsion fractures, isolated triquetral body fractures are a rare injury and often missed. When they are identified, conservative treatment via immobilization is often the standard of care for initial treatment. Rarely, triquetral body fractures can develop into symptomatic nonunions, causing considerable pain and disability. Multiple classification schemes have been described to categorize triquetrum fractures; however, distal triquetrum fractures fit into none of the established models. There is scarce literature describing treatment of triquetral body fracture nonunions. The few reports that exist often use a variation of open reduction internal fixation with or without grafting as treatment. We present the case of an unusual triquetral body fracture nonunion that was successfully treated via surgical excision of the ununited distal fragment

Primary care physicians' perceptions of barriers and facilitators to management of chronic kidney disease: A mixed methods study.

BackgroundGiven the high prevalence of chronic kidney disease (CKD), primary care physicians (PCPs) frequently manage early stage CKD. Nonetheless, there are challenges in providing optimal CKD care in the primary care setting. This study sought to understand PCPs' perceptions of barriers and facilitators to the optimal management of CKD.Study designMixed methods study.Settings and participantsCommunity-based PCPs in four US cities: Baltimore, MD; St. Louis, MO; Raleigh, NC and San Francisco, CA.MethodologyWe used a self-administered questionnaire and conducted 4 focus groups of PCPs (n = 8 PCPs/focus group) in each city to identify key barriers and facilitators to management of patients with CKD in primary care.Analytic approachWe conducted descriptive analyses of the survey data. Major themes were identified from audio-recorded interviews that were transcribed and coded by the research team.ResultsOf 32 participating PCPs, 31 (97%) had been in practice for >10 years, and 29 (91%) practiced in a non-academic setting. PCPs identified multiple barriers to managing CKD in primary care including at the level of the patient (e.g., low awareness of CKD, poor adherence to treatment recommendations), the provider (e.g., staying current with CKD guidelines), and the health care system (e.g., inflexible electronic medical record, limited time and resources). PCPs desired electronic prompts and lab decision support, concise guidelines, and healthcare financing reform to improve CKD care.ConclusionsPCPs face substantial but modifiable barriers in providing care to patients with CKD. Interventions that address these barriers and promote facilitative tools may improve PCPs' effectiveness and capacity to care for patients with CKD

Bench checkout equipment for spaceborne laser altimeter systems

This paper addresses the requirements for testing and characterizing spaceborne laser altimeter systems. The Bench Checkout Equipment (BCE) system, test requirements, and flow-down traceability from the instrument system's functional requirements will also be presented. Mars Observer Laser Altimeter (MOLA) and the MOLA BCE are presented as representative of a 'typical' laser altimeter and its corresponding test system. The testing requirements of other or future laser altimeter systems may vary slightly due to the specific spacecraft interface and project requirements. MOLA, the first solid-state interplanetary laser altimeter, was designed to be operational in Mars orbit for two Earth years. MOLA transmits a 7.5 ns pulse at a wavelength of 1.064 microns with a 0.25 mr beam divergence and a pulse repetition rate of 10 Hz. The output energy is specified at 45 mj at the beginning of mapping orbit and 30 mj at the end of one Martian year. MOLA will measure the laser pulse transit time from the spacecraft to the Mars surface and return to a resolution of 1.5 meters

Instrument Design and In Orbit Performance of Planetary L1dars at NASA GSFC

Space lidars provides a unique and powerful tool in earth environment monitoring and planetary exploration. Lidars operate at a much shorter wavelength than radars and can have a much narrower beam and much smaller transmitter and receiver. Lidars carry their own light sources and can continue measurement day and night, and over polar regions, where the passive instruments cannot observe. NASA Goddard Space Flight Center (GSFC) has developed several space lidars, three of them on planetary missions. These were the Mars Orbiter Laser Altimeter (MOLA) on the Mars Observer and Mars Global Surveyor missions, the Mercury Laser Altimeter (MLA) on the MErcury Surface Space ENvironment, GEochemistry and Ranging (MESSENGER) mission and the Lunar Orbital Laser Altimeter (LOLA) on the Lunar Reconnaissance (LRO) mission. These lidars all use similar technologies but with major improvement from one instrument In the next in size, power, measurement capability and operating environment

Dark Material at the Surface of Polar Crater Deposits on Mercury

Earth-based radar measurements [1-3] have yielded images of radar-bright material at the poles of Mercury postulated to be near-surface water ice residing in cold traps on the permanently shadowed floors of polar impact craters. The Mercury Laser Altimeter (MLA) on board the MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) spacecraft has now mapped much of the north polar region of Mercury [4] (Fig. 1). Radar-bright zones lie within polar craters or along poleward-facing scarps lying mainly in shadow. Calculations of illumination with respect to solid-body motion [5] show that at least 0.5% of the surface area north of 75deg N lies in permanent shadow, and that most such permanently shadowed regions (PSRs) coincide with radar-bright regions. MLA transmits a 1064-nm-wavelength laser pulse at 8 Hz, timing the leading and trailing edges of the return pulse. MLA can in some cases infer energy and thereby surface reflectance at the laser wavelength from the returned pulses. Surficial exposures of water ice would be optically brighter than the surroundings, but persistent surface water ice would require temperatures over all seasons to remain extremely low ( 1 Gy. We describe measurements of reflectivity derived from MLA pulse returns. These reflectivity data show that surface materials in the shadowed regions are darker than their surroundings, enough to strongly attenuate or extinguish laser returns. Such measurements appear to rule out widespread surface exposures of water ice. We consider explanations for the apparent low reflectivity of these regions involving other types of volatile deposit

Sensitivity of mangrove range limits to climate variability

Aim: Correlative distribution models have been used to identify potential climatic controls of mangrove range limits, but there is still uncertainty about the relative importance of these factors across different regions. To provide insights into the strength of climatic control of different mangrove range limits, we tested whether temporal variability in mangrove abundance increases near range limits and whether this variability is correlated with climatic factors thought to control large scale mangrove distributions. Location: North and South America. Time period: 1984–2011. Major taxa studied: Avicennia germinans, Avicennia schuaeriana, Rhizophora mangle, Laguncularia racemosa. Methods: We characterized temporal variability in the enhanced vegetation index (EVI) at mangrove range limits using Landsat satellite imagery collected between 1984–2011. We characterized greening trends at each range limit, examined variability in EVI along latitudinal gradients near each range limit, and assessed correlations between changes in EVI and temperature and precipitation. Results: Spatial variability in mean EVI was generally correlated with temperature and precipitation, but the relationships were region specific. Greening trends were most pronounced at range limits in eastern North America. In these regions variability in EVI increased toward the range limit and was sensitive to climatic factors. In contrast, EVI at range limits on the Pacific coast of North America and both coasts of South America was relatively stable and less sensitive to climatic variability. Main conclusions: Our results suggest that range limits in eastern North America are strongly controlled by climate factors. Mangrove expansion in response to future warming is expected to be rapid in regions that are highly sensitive to climate variability (e.g. eastern North America), but the response in other range limits (e.g. South America) is likely to be more complex and modulated by additional factors such as dispersal limitation, habitat constraints, and/or changing climatic means rather than just extremes

Lifespan extension and the doctrine of double effect

Recent developments in biogerontology—the study of the biology of ageing—suggest that it may eventually be possible to intervene in the human ageing process. This, in turn, offers the prospect of significantly postponing the onset of age-related diseases. The biogerontological project, however, has met with strong resistance, especially by deontologists. They consider the act of intervening in the ageing process impermissible on the grounds that it would (most probably) bring about an extended maximum lifespan—a state of affairs that they deem intrinsically bad. In a bid to convince their deontological opponents of the permissibility of this act, proponents of biogerontology invoke an argument which is grounded in the doctrine of double effect. Surprisingly, their argument, which we refer to as the ‘double effect argument’, has gone unnoticed. This article exposes and critically evaluates this ‘double effect argument’. To this end, we first review a series of excerpts from the ethical debate on biogerontology in order to substantiate the presence of double effect reasoning. Next, we attempt to determine the role that the ‘double effect argument’ is meant to fulfil within this debate. Finally, we assess whether the act of intervening in ageing actually can be justified using double effect reasoning

Foliar water uptake by coastal wetland plants: A novel water acquisition mechanism in arid and humid subtropical mangroves

Climate change alters freshwater availability in many ecosystems leading to shifts in distributions for many plants. Despite living exclusively in intertidal, saline environments, mangroves rely on non-saline water to maintain plant productivity. However, several mangrove species persist in arid environments where non-saline water from rain and groundwater sources are limited. Under these conditions, foliar water uptake from fog and mist may be an important water acquisition strategy. We conducted a field experiment in arid Baja California Sur, Mexico along with a controlled mist chamber experiment (using seedlings sourced from humid subtropical region, Florida, USA) to show that three co-occurring, neotropical mangrove species, Avicennia germinans, Laguncularia racemosa and Rhizophora mangle, growing in both arid and humid environments can access water condensed on their leaves. Foliar water uptake was greatest in A. germinans and lowest in R. mangle, possibly reflecting leaf traits associated with species-specific water balance strategies. In our field misting experiment, the contribution of foliar water uptake was higher in A. germinans (32 ± 2%) than L. racemosa (26 ± 2%) and R. mangle (16 ± 1%). Foliar water uptake also varied across locations for L. racemosa and R. mangle, with declining uptake towards both species’ northern range limits in Baja California Sur, suggesting the distribution patterns of arid-zone mangroves may be affected by species-specific spatial variation in foliar water use. Within species, foliar water use was comparable across field and controlled experiments irrespective of source population (Baja California Sur vs. Florida), suggesting foliar water uptake is not an arid-zone adaptation, and is instead used as a supplemental water balance strategy in arid and humid neotropical mangroves. Synthesis. Our findings indicate mangroves have the potential to access atmospheric water, such as rain, dew and sea fog, through their leaves to offset soil water deficits. Variation in foliar water use across these three neotropical mangrove species may influence mangrove species distributions across arid-zone and pseudo-drought (highly saline) environments, with implications for mangrove response to climate change