377 research outputs found
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High-resolution temperature variability reconstructed from black pine tree ring densities in Southern Spain
The presence of an ancient, high-elevation pine forest in the Natural Park of Sierras de Cazorla in southern Spain, including some trees reaching >700 years, stimulated efforts to develop high-resolution temperature reconstructions in an otherwise drought-dominated region. Here, we present a reconstruction of spring and fall temperature variability derived from black pine tree ring maximum densities reaching back to 1350 Coefficient of Efficiency (CE). The reconstruction is accompanied by large uncertainties resulting from low interseries correlations among the single trees and a limited number of reliable instrumental stations in the study region. The reconstructed temperature history reveals warm conditions during the early 16th and 19th centuries that were of similar magnitude to the warm temperatures recorded since the late 20th century. A sharp transition from cold conditions in the late 18th century (t1781–1810 = −1.15 °C ± 0.64 °C) to warm conditions in the early 19th century (t1818–1847 = −0.06 °C ± 0.49 °C) is centered around the 1815 Tambora eruption (t1816 = −2.1 °C ± 0.55 °C). The new reconstruction from southern Spain correlates significantly with high-resolution temperature histories from the Pyrenees located ~600 km north of the Cazorla Natural Park, an association that is temporally stable over the past 650 years (r1350–2005 > 0.3, p < 0.0001) and particularly strong in the high-frequency domain (rHF > 0.4). Yet, only a few of the reconstructed cold extremes (1453, 1601, 1816) coincide with large volcanic eruptions, suggesting that the severe cooling events in southern Spain are controlled by internal dynamics rather than external (volcanic) forcing.</jats:p
Modernizing and Expanding the NASA Space Geodesy Network to Meet Future Geodetic Requirements
NASA maintains and operates a global network of Very Long Baseline Interferometry (VLBI), Satellite Laser Ranging (SLR), and Global Navigation Satellite System ground stations as part of the NASA Space Geodesy Program. The NASA Space Geodesy Network (NSGN) provides the geodetic products that support Earth observations and the related science requirements as outlined by the US National Research Council (NRC in Precise geodetic infrastructure: national requirements for a shared resource, National Academies Press, Washington, 2010. http://nap.edu/12954, Thriving on our changing planet: a decadal strategy for Earth observation from space, National Academies Press, Washington, 2018. http://nap.edu/24938). The Global Geodetic Observing System (GGOS) and the NRC have set an ambitious goal of improving the Terrestrial Reference Frame to have an accuracy of 1 mm and stability of 0.1 mm per year, an order of magnitude beyond current capabilities. NASA and its partners within GGOS are addressing this challenge by planning and implementing modern geodetic stations colocated at existing and new sites around the world. In 2013, NASA demonstrated the performance of its next-generation systems at the prototype next-generation core site at NASAs Goddard Geophysical and Astronomical Observatory in Greenbelt, Maryland. Implementation of a new broadband VLBI station in Hawaii was completed in 2016. NASA is currently implementing new VLBI and SLR stations in Texas and is planning the replacement of its other aging domestic and international legacy stations. In this article, we describe critical gaps in the current global network and discuss how the new NSGN will expand the global geodetic coverage and ultimately improve the geodetic products. We also describe the characteristics of a modern NSGN site and the capabilities of the next-generation NASA SLR and VLBI systems. Finally, we outline the plans for efficiently operating the NSGN by centralizing and automating the operations of the new geodetic stations
Lower numbers of natural killer T cells in HIV-1 and Mycobacterium leprae co-infected patients
Natural killer T (NKT) cells are a heterogeneous population of lymphocytes that recognize antigens presented by CD1d and have attracted attention because of their potential role linking innate and adaptive immune responses. Peripheral NKT cells display a memory-activated phenotype and can rapidly secrete large amounts of pro-inflammatory cytokines upon antigenic activation. In this study, we evaluated NKT cells in the context of patients co-infected with HIV-1 and Mycobacterium leprae. The volunteers were enrolled into four groups: 22 healthy controls, 23 HIV-1-infected patients, 20 patients with leprosy and 17 patients with leprosy and HIV-1-infection. Flow cytometry and ELISPOT assays were performed on peripheral blood mononuclear cells. We demonstrated that patients co-infected with HIV-1 and M.leprae have significantly lower NKT cell frequencies [median 0.022%, interquartile range (IQR): 0.0070.051] in the peripheral blood when compared with healthy subjects (median 0.077%, IQR: 0.0320.405, P < 0.01) or HIV-1 mono-infected patients (median 0.072%, IQR: 0.0300.160, P < 0.05). Also, more NKT cells from co-infected patients secreted interferon-? after stimulation with DimerX, when compared with leprosy mono-infected patients (P = 0.05). These results suggest that NKT cells are decreased in frequency in HIV-1 and M.leprae co-infected patients compared with HIV-1 mono-infected patients alone, but are at a more activated state. Innate immunity in human subjects is strongly influenced by their spectrum of chronic infections, and in HIV-1-infected subjects, a concurrent mycobacterial infection probably hyper-activates and lowers circulating NKT cell numbers.National Institutes of Health [R01-AI52731, AI060379]Fogarty International Center [D43 TW00003]Fundacao de Amparo a Pesquisa do Estado de Sao Paulo [04/15856-9/Kallas, 2010/05845-0/Kallas]Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPq)Brazilian Ministry of Science and Technology [484230/2011-5]New York Community Trus
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Multiple viral infections in Agaricus bisporus - characterisation of 18 unique RNA viruses and 8 ORFans identified by deep sequencing
Thirty unique non-host RNAs were sequenced in the cultivated fungus, Agaricus bisporus, comprising 18 viruses each encoding an RdRp domain with an additional 8 ORFans (non-host RNAs with no similarity to known sequences). Two viruses were multipartite with component RNAs showing correlative abundances and common 3′ motifs. The viruses, all positive sense single-stranded, were classified into diverse orders/families. Multiple infections of Agaricus may represent a diverse, dynamic and interactive viral ecosystem with sequence variability ranging over 2 orders of magnitude and evidence of recombination, horizontal gene transfer and variable fragment numbers. Large numbers of viral RNAs were detected in multiple Agaricus samples; up to 24 in samples symptomatic for disease and 8–17 in asymptomatic samples, suggesting adaptive strategies for co-existence. The viral composition of growing cultures was dynamic, with evidence of gains and losses depending on the environment and included new hypothetical viruses when compared with the current transcriptome and EST databases. As the non-cellular transmission of mycoviruses is rare, the founding infections may be ancient, preserved in wild Agaricus populations, which act as reservoirs for subsequent cell-to-cell infection when host populations are expanded massively through fungiculture
Reconstructing 800Â years of summer temperatures in Scotland from tree rings
We thank The Carnegie Trust for the Universities of Scotland for providing funding for Miloš Rydval’s PhD. The Scottish pine network expansion has been an ongoing task since 2007 and funding must be acknowledged to the following projects: EU project ‘Millennium’ (017008-2), Leverhulme Trust project ‘RELiC: Reconstructing 8000 years of Environmental and Landscape change in the Cairngorms (F/00 268/BG)’ and the NERC project ‘SCOT2K: Reconstructing 2000 years of Scottish climate from tree rings (NE/K003097/1)’.This study presents a summer temperature reconstruction using Scots pine tree-ring chronologies for Scotland allowing the placement of current regional temperature changes in a longer-term context. ‘Living-tree’ chronologies were extended using ’subfossil’ samples extracted from nearshore lake sediments resulting in a composite chronology > 800 years in length. The North Cairngorms (NCAIRN) reconstruction was developed from a set of composite blue intensity high-pass and ring-width low-pass chronologies with a range of detrending and disturbance correction procedures. Calibration against July-August mean temperature explains 56.4% of the instrumental data variance over 1866-2009 and is well verified. Spatial correlations reveal strong coherence with temperatures over the British Isles, parts of western Europe, southern Scandinavia and northern parts of the Iberian Peninsula. NCAIRN suggests that the recent summer-time warming in Scotland is likely not unique when compared to multi-decadal warm periods observed in the 1300s, 1500s, and 1730s, although trends before the mid-16th century should be interpreted with some caution due to greater uncertainty. Prominent cold periods were identified from the 16th century until the early 1800s – agreeing with the so-called Little Ice Age observed in other tree-ring reconstructions from Europe - with the 1690s identified as the coldest decade in the record. The reconstruction shows a significant cooling response one year following volcanic eruptions although this result is sensitive to the datasets used to identify such events. In fact, the extreme cold (and warm) years observed in NCAIRN appear more related to internal forcing of the summer North Atlantic Oscillation.Publisher PDFPeer reviewe
Adipose tissue pathways involved in weight loss of cancer cachexia
White adipose tissue (WAT) constitutes our most expandable tissue and largest
endocrine organ secreting hundreds of polypeptides collectively termed adipokines.
Changes in WAT mass induce alterations in adipocyte secretion and function, which
are linked to disturbed whole-body metabolism. Although the mechanisms controlling
this are not clear they are dependent on changes in gene expression, a complex process
which is regulated at several levels. Results in recent years have highlighted the role of
small non-coding RNA molecules termed microRNAs (miRNAs), which regulate gene
expression via post-transcriptional mechanisms. The aim of this thesis was to
characterize global gene expression levels and describe novel miRNAs and adipokines
controlling the function of human WAT in conditions with pathological increases or
decreases in WAT mass. Obesity and cancer cachexia were selected as two models
since they are both clinically relevant and characterized by involuntary changes in
WAT mass.
In Study I, expressional analyses were performed in subcutaneous WAT from cancer
patients with or without cachexia and obese versus non-obese subjects. In total, 425
transcripts were found to be regulated in cancer cachexia. Pathway analyses based on
this set of genes revealed that processes involving extracellular matrix, actin
cytoskeleton and focal adhesion were significantly downregulated, whereas fatty acid
metabolism was upregulated comparing cachectic with weight-stable cancer subjects.
Furthermore, by overlapping these results with microarray data from an obesity study,
many transcripts were found to be reciprocally regulated comparing the two conditions.
This suggests that WAT gene expression in cancer cachexia and obesity are regulated
by similar, albeit opposing, mechanisms.
In Study II, the focus was on the family of
fibroblast growth factors (FGFs), members of which have recently been implicated in
the development of obesity and insulin resistance. A retrospective analysis of global
gene expression data identified several FGFs (FGF1/2/7/9/13/18) to be expressed in
WAT. However, only one, FGF1, was actively secreted from WAT and predominantly
so from the adipocyte fraction. Moreover, FGF1 release was increased in obese
compared to non-obese subjects, but was not normalized by weight loss. Although the
clinical significance of these findings is not yet clear, it can be hypothesized that FGF1
may play a role in WAT growth, possibly by promoting fat cell proliferation and/or
differentiation.
In Study III, we identified adipose miRNAs regulated in obesity. Out
of eleven miRNAs regulated by changes in body fat mass, ten controlled the production
of the pro-inflammatory chemoattractant chemokine (C-C motif) ligand 2 (CCL2)
when overexpressed in fat cells and for two, miR-126 and -193b, signaling circuits
were defined.
In Study IV, a novel adipokine, semaphorin 3C (SEMA3C), was
identified by combining transcriptome and secretome data. Detailed studies focusing on
SEMA3C revealed that this factor was secreted from adipocytes and induced the
expression of extracellular matrix and matricellular genes in preadipocytes.
Furthermore, SEMA3C mRNA levels correlated with interstitial fibrosis and insulin
resistance in WAT derived from subjects with a wide range in BMI.
In summary, the results presented in this thesis have delineated transcriptional
alterations in WAT in two clinically relevant conditions, obesity and cancer cachexia.
This has allowed the identification of novel adipokines and microRNAs with potential
pathophysiological importance. These findings form the basis for further studies aiming
at understanding the central role of WAT in disorders associated with metabolic
complications
Randomized, double-blind, placebo-controlled clinical trial to assess the safety and effectiveness of a novel dual-action oral topical formulation against upper respiratory infections
Novas possibilidades metodológicas: a quebra dos paradigmas qualitativo e quantitativo em psicologia
Skewed Distribution of Circulating Activated Natural Killer T (NKT) Cells in Patients with Common Variable Immunodeficiency Disorders (CVID)
Common variable immunodeficiency disorder (CVID) is the commonest cause of primary antibody failure in adults and children, and characterized clinically by recurrent bacterial infections and autoimmune manifestations. Several innate immune defects have been described in CVID, but no study has yet investigated the frequency, phenotype or function of the key regulatory cell population, natural killer T (NKT) cells. We measured the frequencies and subsets of NKT cells in patients with CVID and compared these to healthy controls. Our results show a skewing of NKT cell subsets, with CD4+ NKT cells at higher frequencies, and CD8+ NKT cells at lower frequencies. However, these cells were highly activated and expression CD161. The NKT cells had a higher expression of CCR5 and concomitantly expression of CCR5+CD69+CXCR6 suggesting a compensation of the remaining population of NKT cells for rapid effector action
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