3,200 research outputs found
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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
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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
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: 1984â2011.
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 1984â2011. 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
Dynamic analysis of amyloid β-protein in behaving mice reveals opposing changes in ISF versus parenchymal Aβ during age-related plaque formation
Growing evidence supports the hypothesis that soluble, diffusible forms of the amyloid β-peptide (Aβ) are pathogenically important in Alzheimerâs disease (AD) and thus have both diagnostic and therapeutic salience. To learn more about the dynamics of soluble Aβ economy in vivo, we sampled by microdialysis the brain interstitial fluid (ISF), which contains the most soluble Aβ species in brain at steady state, in >40 wake, behaving APP transgenic mice before and during the process of Aβ plaque formation (age 3â28 months). Diffusible forms of Aβ, especially Aβ(42), declined significantly in ISF as mice underwent progressive parenchymal deposition of Aβ. Moreover, radiolabeled Aβ administered at physiological concentrations into ISF revealed a striking difference in the fate of soluble Aβ in plaque-rich (vs. -free) mice: it clears more rapidly from the ISF and becomes more associated with the TBS-extractable pool, suggesting that cerebral amyloid deposits can rapidly sequester soluble Aβ from the ISF. Likewise, acute Îł-secretase inhibition in plaque-free mice showed a marked decline of Aβ(38), Aβ(40) and Aβ(42), whereas in plaque- rich mice, Aβ(42) declined significantly less. These results suggest that most of the Aβ(42) that populates the ISF in plaque-rich mice is derived not from new Aβ biosynthesis but rather from the large reservoir of less soluble Aβ(42) in brain parenchyma. Together, these and other findings herein illuminate the in vivo dynamics of soluble Aβ during the development of AD-type neuropathology and after Îł-secretase inhibition and help explain the apparent paradox that cerebrospinal fluid Aβ(42) levels fall as humans develop AD
Habitat Demonstration Unit (HDU) Vertical Cylinder Habitat
NASA's Constellation Architecture Team defined an outpost scenario optimized for intensive mobility that uses small, highly mobile pressurized rovers supported by portable habitat modules that can be carried between locations of interest on the lunar surface. A compact vertical cylinder characterizes the habitat concept, where the large diameter maximizes usable flat floor area optimized for a gravity environment and allows for efficient internal layout. The module was sized to fit into payload fairings for the Constellation Ares V launch vehicle, and optimized for surface transport carried by the All-Terrain Hex-Limbed Extra-Terrestrial Explorer (ATHLETE) mobility system. Launch and other loads are carried through the barrel to a top and bottom truss that interfaces with a structural support unit (SSU). The SSU contains self-leveling feet and docking interfaces for Tri-ATHLETE grasping and heavy lift. A pressurized module needed to be created that was appropriate for the lunar environment, could be easily relocated to new locations, and could be docked together in multiples for expanding pressurized volume in a lunar outpost. It was determined that horizontally oriented pressure vessels did not optimize floor area, which takes advantage of the gravity vector for full use. Hybrid hard-inflatable habitats added an unproven degree of complexity that may eventually be worked out. Other versions of vertically oriented pressure vessels were either too big, bulky, or did not optimize floor area. The purpose of the HDU vertical habitat module is to provide pressurized units that can be docked together in a modular way for lunar outpost pressurized volume expansion, and allow for other vehicles, rovers, and modules to be attached to the outpost to allow for IVA (intra-vehicular activity) transfer between them. The module is a vertically oriented cylinder with a large radius to allow for maximal floor area and use of volume. The modular, 5- m-diameter HDU vertical habitat module consists of a 2-m-high barrel with 0.6-mhigh end domes forming the 56-cubicmeter pressure vessel, and a 19-squaremeter floor area. The module has up to four docking ports located orthogonally from each other around the perimeter, and up to one docking port each on the top or bottom end domes. In addition, the module has mounting trusses top and bottom for equipment, and to allow docking with the ATHLETE mobility system. Novel or unique features of the HDU vertical habitat module include the nodelike function with multiple pressure hatches for docking with other versions of itself and other modules and vehicles; the capacity to be carried by an ATHLETE mobility system; and the ability to attach inflatable 'attic' domes to the top for additional pressurized volume
Evidence for a core gut microbiota in the zebrafish
Experimental analysis of gut microbial communities and their interactions with vertebrate hosts is conducted predominantly in domesticated animals that have been maintained in laboratory facilities for many generations. These animal models are useful for studying coevolved relationships between host and microbiota only if the microbial communities that occur in animals in lab facilities are representative of those that occur in nature. We performed 16S rRNA gene sequence-based comparisons of gut bacterial communities in zebrafish collected recently from their natural habitat and those reared for generations in lab facilities in different geographic locations. Patterns of gut microbiota structure in domesticated zebrafish varied across different lab facilities in correlation with historical connections between those facilities. However, gut microbiota membership in domesticated and recently caught zebrafish was strikingly similar, with a shared core gut microbiota. The zebrafish intestinal habitat therefore selects for specific bacterial taxa despite radical differences in host provenance and domestication status
Complete genome sequence of Candidatus Ruthia magnifica
The hydrothermal vent clam Calyptogena magnifica (Bivalvia: Mollusca) is a member of the Vesicomyidae. Species within this family form symbioses with chemosynthetic Gammaproteobacteria. They exist in environments such as hydrothermal vents and cold seeps and have a rudimentary gut and feeding groove, indicating a large dependence on their endosymbionts for nutrition. The C. magnifica symbiont, Candidatus Ruthia magnifica, was the first intracellular sulfur-oxidizing endosymbiont to have its genome sequenced (Newton et al. 2007). Here we expand upon the original report and provide additional details complying with the emerging MIGS/MIMS standards. The complete genome exposed the genetic blueprint of the metabolic capabilities of the symbiont. Genes which were predicted to encode the proteins required for all the metabolic pathways typical of free-living chemoautotrophs were detected in the symbiont genome. These include major pathways including carbon fixation, sulfur oxidation, nitrogen assimilation, as well as amino acid and cofactor/vitamin biosynthesis. This genome sequence is invaluable in the study of these enigmatic associations and provides insights into the origin and evolution of autotrophic endosymbiosis
A Taxonomy and Results from a Comprehensive Review of 28 Maternal Health Voucher Programmes
It is increasingly clear that Millennium Development Goal 4 and 5 will
not be achieved in many low- and middle-income countries with the
weakest gains among the poor. Recognizing that there are large
inequalities in reproductive health outcomes, the post-2015 agenda on
universal health coverage will likely generate strategies that target
resources where maternal and newborn deaths are the highest. In 2012,
the United States Agency for International Development convened an
Evidence Summit to review the knowledge and gaps on the utilization of
financial incentives to enhance the quality and uptake of maternal
healthcare. The goal was to provide donors and governments of the low-
and middle-income countries with evidenceinformed recommendations on
practice, policy, and strategies regarding the use of financial
incentives, including vouchers, to enhance the demand and supply of
maternal health services. The findings in this paper are intended to
guide governments interested in maternal health voucher programmes with
recommendations for sustainable implementation and impact. The Evidence
Summit undertook a systematic review of five financing strategies. This
paper presents the methods and findings for vouchers, building on a
taxonomy to catalogue knowledge about voucher programme design and
functionality. More than 120 characteristics under five major
categories were identified: programme principles (objectives and
financing); governance and management; benefits package and beneficiary
targeting; providers (contracting and service pricing); and
implementation arrangements (marketing, claims processing, and
monitoring and evaluation). Among the 28 identified maternal health
voucher programmes, common characteristics included: a stated objective
to increase the use of services among the means-tested poor;
contracted-out programme management; contracting either exclusively
private facilities or a mix of public and private providers;
prioritizing community-based distribution of vouchers; and tracking
individual claims for performance purposes. Maternal voucher programmes
differed on whether contracted providers were given training on
clinical or administrative issues; whether some form of service
verification was undertaken at facility or communitylevel; and the
relative size of programme management costs in the overall programme
budget. Evidence suggests voucher programmes can serve populations with
national-level impact. Reaching scale depends on whether the voucher
programme can: (i) keep management costs low, (ii) induce a large
demand-side response among the bottom two quintiles, and (iii) achieve
a quality of care that translates a greater number of facility-based
deliveries into a reduction in maternal morbidity and mortality
Search for the standard model Higgs boson in the H to ZZ to 2l 2nu channel in pp collisions at sqrt(s) = 7 TeV
A search for the standard model Higgs boson in the H to ZZ to 2l 2nu decay
channel, where l = e or mu, in pp collisions at a center-of-mass energy of 7
TeV is presented. The data were collected at the LHC, with the CMS detector,
and correspond to an integrated luminosity of 4.6 inverse femtobarns. No
significant excess is observed above the background expectation, and upper
limits are set on the Higgs boson production cross section. The presence of the
standard model Higgs boson with a mass in the 270-440 GeV range is excluded at
95% confidence level.Comment: Submitted to JHE
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