7,780 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
Increased trend in extracorporeal membrane oxygenation use by adults in the United States since 2007
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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
The ePetri dish, an on-chip cell imaging platform based on subpixel perspective sweeping microscopy (SPSM)
We report a chip-scale lensless wide-field-of-view microscopy imaging technique, subpixel perspective sweeping microscopy, which can render microscopy images of growing or confluent cell cultures autonomously. We demonstrate that this technology can be used to build smart Petri dish platforms, termed ePetri, for cell culture experiments. This technique leverages the recent broad and cheap availability of high performance image sensor chips to provide a low-cost and automated microscopy solution. Unlike the two major classes of lensless microscopy methods, optofluidic microscopy and digital in-line holography microscopy, this new approach is fully capable of working with cell cultures or any samples in which cells may be contiguously connected. With our prototype, we demonstrate the ability to image samples of area 6 mm Ă— 4 mm at 660-nm resolution. As a further demonstration, we showed that the method can be applied to image color stained cell culture sample and to image and track cell culture growth directly within an incubator. Finally, we showed that this method can track embryonic stem cell differentiations over the entire sensor surface. Smart Petri dish based on this technology can significantly streamline and improve cell culture experiments by cutting down on human labor and contamination risks
Tevatron-for-LHC Report: Preparations for Discoveries
This is the "TeV4LHC" report of the "Physics Landscapes" Working Group,
focused on facilitating the start-up of physics explorations at the LHC by
using the experience gained at the Tevatron. We present experimental and
theoretical results that can be employed to probe various scenarios for physics
beyond the Standard Model.Comment: 222 pp., additional contribution added, typos/layout correcte
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
Cutaneous nociception evoked by 15-delta PGJ2 via activation of ion channel TRPA1
<p>Abstract</p> <p>Background</p> <p>A number of prostaglandins (PGs) sensitize dorsal root ganglion (DRG) neurons and contribute to inflammatory hyperalgesia by signaling through specific G protein-coupled receptors (GPCRs). One mechanism whereby PGs sensitize these neurons is through modulation of "thermoTRPs," a subset of ion channels activated by temperature belonging to the Transient Receptor Potential ion channel superfamily. Acrid, electrophilic chemicals including cinnamaldehyde (CA) and allyl isothiocyanate (AITC), derivatives of cinnamon and mustard oil respectively, activate thermoTRP member TRPA1 via direct modification of channel cysteine residues.</p> <p>Results</p> <p>Our search for endogenous chemical activators utilizing a bioactive lipid library screen identified a cyclopentane PGD<sub>2 </sub>metabolite, 15-deoxy-Δ<sup>12,14</sup>-prostaglandin J<sub>2 </sub>(15d-PGJ<sub>2</sub>), as a TRPA1 agonist. Similar to CA and AITC, this electrophilic molecule is known to modify cysteines of cellular target proteins. Electophysiological recordings verified that 15d-PGJ<sub>2 </sub>specifically activates TRPA1 and not TRPV1 or TRPM8 (thermoTRPs also enriched in DRG). Accordingly, we identified a population of mouse DRG neurons responsive to 15d-PGJ<sub>2 </sub>and AITC that is absent in cultures derived from TRPA1 knockout mice. The irritant molecules that activate TRPA1 evoke nociceptive responses. However, 15d-PGJ<sub>2 </sub>has not been correlated with painful sensations; rather, it is considered to mediate anti-inflammatory processes via binding to the nuclear peroxisome proliferator-activated receptor gamma (PPARγ). Our <it>in vivo </it>studies revealed that 15d-PGJ<sub>2 </sub>induced acute nociceptive responses when administered cutaneously. Moreover, mice deficient in the TRPA1 channel failed to exhibit such behaviors.</p> <p>Conclusion</p> <p>In conclusion, we show that 15d-PGJ<sub>2 </sub>induces acute nociception when administered cutaneously and does so via a TRPA1-specific mechanism.</p
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