862 research outputs found
Resting state correlates of subdimensions of anxious affect
Resting state fMRI may help identify markers of risk for affective disorder. Given the comorbidity of anxiety and depressive disorders and the heterogeneity of these disorders as defined by DSM, an important challenge is to identify alterations in resting state brain connectivity uniquely associated with distinct profiles of negative affect. The current study aimed to address this by identifying differences in brain connectivity specifically linked to cognitive and physiological profiles of anxiety, controlling for depressed affect. We adopted a two-stage multivariate approach. Hierarchical clustering was used to independently identify dimensions of negative affective style and resting state brain networks. Combining the clustering results, we examined individual differences in resting state connectivity uniquely associated with subdimensions of anxious affect, controlling for depressed affect. Physiological and cognitive subdimensions of anxious affect were identified. Physiological anxiety was associated with widespread alterations in insula connectivity, including decreased connectivity between insula subregions and between the insula and other medial frontal and subcortical networks. This is consistent with the insula facilitating communication between medial frontal and subcortical regions to enable control of physiological affective states. Meanwhile, increased connectivity within a frontoparietal-posterior cingulate cortex-precunous network was specifically associated with cognitive anxiety, potentially reflecting increased spontaneous negative cognition (e.g., worry). These findings suggest that physiological and cognitive anxiety comprise subdimensions of anxiety-related affect and reveal associated alterations in brain connectivity
Deoxyfluorination using CuF2 : enabled by a Lewis base activating group strategy
We thank the University of St Andrews for PhD studentships (D.E.S and S.C.), GlaxoSmithKline and the University of Glasgow for financial support.Deoxyfluorination is a primary method for the formation of C–F bonds. Bespoke reagents are commonly used due to issues associated with the low reactivity of metal fluorides. Here, we report the development of a simple strategy for deoxyfluorination using first‐row transition metal fluorides that overcomes these limitations. Using CuF2 as an exemplar, activation of an O ‐alkylisourea adduct formed in situ allows effective nucleophilic fluoride transfer to a range of primary and secondary alcohols. Spectroscopic investigations have been used to probe the origin of the enhanced reactivity of CuF2 . The utility of the process towards enabling 18F‐radiolabeling is also presented.PostprintPeer reviewe
CloudTracks: A Dataset for Localizing Ship Tracks in Satellite Images of Clouds
Clouds play a significant role in global temperature regulation through their
effect on planetary albedo. Anthropogenic emissions of aerosols can alter the
albedo of clouds, but the extent of this effect, and its consequent impact on
temperature change, remains uncertain. Human-induced clouds caused by ship
aerosol emissions, commonly referred to as ship tracks, provide visible
manifestations of this effect distinct from adjacent cloud regions and
therefore serve as a useful sandbox to study human-induced clouds. However, the
lack of large-scale ship track data makes it difficult to deduce their general
effects on cloud formation. Towards developing automated approaches to localize
ship tracks at scale, we present CloudTracks, a dataset containing 3,560
satellite images labeled with more than 12,000 ship track instance annotations.
We train semantic segmentation and instance segmentation model baselines on our
dataset and find that our best model substantially outperforms previous
state-of-the-art for ship track localization (61.29 vs. 48.65 IoU). We also
find that the best instance segmentation model is able to identify the number
of ship tracks in each image more accurately than the previous state-of-the-art
(1.64 vs. 4.99 MAE). However, we identify cases where the best model struggles
to accurately localize and count ship tracks, so we believe CloudTracks will
stimulate novel machine learning approaches to better detect elongated and
overlapping features in satellite images. We release our dataset openly at
{zenodo.org/records/10042922}.Comment: 11 pages, 5 figures, submitted to Journal of Machine Learning
Researc
Policy options for the world’s primary forests in multilateral environmental agreements
We identify policies that would provide a solid foundation in key international negotiations to ensure that primary forests persist into the 21st Century. A novel compilation of primary forest cover and other data revealed that protection of primary forests is a matter of global concern being equally distributed between developed and developing countries. Almost all (98%) of primary forest is found within 25 countries with around half in five developed ones (USA, Canada, Russia, Australia, and NZ). Only approximate to 22% of primary forest is found in IUCN Protected Areas Categories I-VI, which is approximately 5% of preagriculture natural forest cover. Rates of deforestation and forest degradation are rapid and extensive, and the long-term integrity of primary forest cannot be assumed. We recommend four new actions that could be included in climate change, biodiversity, and sustainable development negotiations: (1) recognize primary forests as a matter of global concern within international negotiations; (2) incorporate primary forests into environmental accounting; (3) prioritize the principle of avoided loss; and (4) universally accept the important role of indigenous and community conserved areas. In the absence of specific policies for primary forest protection, their unique biodiversity values and ecosystem services will continue to erode
Identification and Characterization of the Unique N-Linked Glycan Common to the Flagellins and S-layer Glycoprotein of Methanococcus voltae*
The flagellum of Methanococcus voltae is composed of four structural flagellin proteins FlaA, FlaB1, FlaB2, and FlaB3. These proteins possess a total of 15 potential N-linked sequons (NX(S/T)) and show a mass shift on an SDS-polyacrylamide gel indicating significant post-translational modification. We describe here the structural characterization of the flagellin glycan from M. voltae using mass spectrometry to examine the proteolytic digests of the flagellin proteins in combination with NMR analysis of the purified glycan using a sensitive, cryogenically cooled probe. Nano-liquid chromatography-tandem mass spectrometry analysis of the proteolytic digests of the flagellin proteins revealed that they are post-translationally modified with a novel N-linked trisaccharide of mass 779 Da that is composed of three sugar residues with masses of 318, 258, and 203 Da, respectively. In every instance the glycan is attached to the peptide through the asparagine residue of a typical N-linked sequon. The glycan modification has been observed on 14 of the 15 sequon sites present on the four flagellin structural proteins. The novel glycan structure elucidated by NMR analysis was shown to be a trisaccharide composed of beta-ManpNAcA6Thr-(1-4)-beta-Glc-pNAc3NAcA-(1-3)-beta-GlcpNAc linked to Asn. In addition, the same trisaccharide was identified on a tryptic peptide of the S-layer protein from this organism implicating a common N-linked glycosylation pathway
Advancing values-based approaches to climate change adaptation : a case study from Australia
Coastal flooding affects physical and social place attachments. Values-based approaches to climate change adaptation examine how risks to place attachments are distributed within and among communities, with a view to informing equitable adaptation policies. In this nascent body of research, divergent theoretical frameworks and empirical approaches to measuring social values are evolving. While some studies explore the things people value about their everyday lives generally—the lived values approach, others locate specific social and cultural values in geographic space—the landscape values mapping approach. This study aims to compare the explanatory value of these two approaches for understanding the social risks of sea-level rise, and appraise whether either or both approaches are likely to meet local adaptation planning needs. It does this by examining the potential social impacts of sea-level rise in Kingston Beach, Australia, informed by a mail-out survey of the community. The lived values approach identified that the natural environment, scenery, relaxed lifestyle and safety are highly important to local residents, while the landscape values mapping approach revealed that Kingston Main Beach is the most highly valued of eight coastal landscape units. Incorporating the landscape values mapping into the lived values cluster analysis revealed that while Kingston Main Beach is highly important for its recreational value to some members of the community, for others manmade features such as community halls or sports ovals may be of higher importance because they facilitate social interactions. There is potential to further integrate these two approaches to better inform adaptation policy about how lived and landscape values are distributed among communities, where they are located in space and whether they change over time. A deeper understanding of such assigned values can lead to improved engagement with coastal residents to inform adaptation policy now and into the future
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Reply to Comment on "Pervasive remagnetization of detrital zircon host rocks in the Jack Hills, Western Australia and implications for records of the early dynamo"
Determining the history of Earth's dynamo prior to the oldest known well-preserved rock record is one of the ultimate challenges in the field of paleomagnetism. Tarduno et al. (2015) argued that detrital zircons contain records of an active dynamo dating back to 4.2 billion years ago (Ga), 700 million years earlier than previously identified (Biggin et al., 2011 and Tarduno et al., 2010). However, this extraordinary claim requires evidence that the zircons have not been remagnetized during the intervening time since their formation. Weiss et al. (2015) argued that such evidence had yet to be provided, a conclusion that we find still firmly holds
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