8,722 research outputs found
340 years of atmospheric circulation characteristics reconstructed from an eastern Antarctic Peninsula ice core
Copyright @ 2006 American Geophysical Union (AGU)Precipitation delivery mechanisms for Dolleman Island (DI), located off the east coast of the Antarctic Peninsula, are investigated using reanalysis and back trajectory data. The Southern Annular Mode (SAM) and ENSO are both shown to influence precipitation delivery and event size. Precipitation delivery variability is compared against the interannual variation of chemical data from two DI ice cores. Nitrate concentration in the cores is strongly linked with the ratio of easterly to westerly back trajectories arriving at DI, as described by a Cross-Peninsula Index (CPI) defined in this paper. This CPI is used subsequently to reconstruct the atmospheric circulation characteristics for the 340-year ice core record. The analysis highlights a period of increased easterlies during 1720–1780 and an increase in westerlies for 1950–1980, the latter concomitant with a positive SAM trend and western Peninsula warming. The reconstruction also reveals periods when polynyas may have been present in the Weddell Sea
The roles, mechanisms, and controversies of autophagy in mammalian biology
Autophagy is a universally conserved metabolic program of catabolism that plays important roles in energy homeostasis and impacts both normal physiology and multiple disease processes, including cancer. Autophagy has been documented as a pro-survival mechanism used to maintain viability under starvation conditions; however, conflicting findings have also implicated autophagy in the control of cell death. Adding to the controversy, central mediators of autophagy have been implicated in both pro-survival and pro-death processes. This report highlights recent insights into our understanding of how autophagy is regulated and newly discovered physiological roles for autophagy in normal biology and disease
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Petrology and geochemistry of nakhlite MIL 03346: A new Martian meteorite from Antarctica
MIL 03346 is the first nakhlite in the US Antarctic collection. We have performed detailed mineralogical and bulk-geochemical investigations to compare petrogenesis of this Martian meteorite with other nakhlites
In situ aerosol measurements taken during the 2007 COPS field campaign at the Hornisgrinde ground site
Copyright @ 2011 Royal Meteorological Society.The Convective and Orographically-induced Precipitation Study (COPS) campaign was conducted during the summer of 2007. A suite of instruments housed at the top of the Hornisgrinde Mountain (1156 m) in the Black Forest region of south-west Germany provided datasets that allow an investigation into the physical, chemical and hygroscopic properties of the aerosol particles sampled during COPS. Organic mass loadings were found to dominate the aerosol composition for the majority of the project, exceeding 8 µg m−3 during a period of high pressure, high temperature, and low wind speed. The ratio of organic:sulphate sub-micron mass concentration exceeds 10:1 during the same time period. Back trajectories show air from this time-frame passing slowly over the local forest and not passing over any local anthropogenic sources. Occasional peaks in nitrate mass loadings were associated with changes in the typical wind direction from south-westerly to north-westerly where air had passed over the Stuttgart region. Size distribution data shows a dominant accumulation-mode when the measurement site was free from precipitation events. A sharp increase in ultrafine particle number concentration was seen during most days commencing around noon. The apparent growth of these particles is associated with an increase in organic mass loading, suggesting condensational growth. For the most part, with the exception of the high pressure period, the aerosol properties recorded during COPS were comparable to previous studies of continental aerosol properties.NER
Gold-Catalyzed Direct Arylation
Gently Coupled
Linked aryl rings are found in a broad range of commercial chemical products. Currently, the most versatile synthetic route to this motif involves cross-coupling of one ring with a halide substituent to another ring with a boron or metal-based substituent. Recent research has focused on eliminating the need for one or both of these activating substituents, but for the most part, the emerging methods have required high temperatures and high concentrations of one coupling partner.
Ball
et al.
(p.
1644
) now present a gold catalyst that can couple silyl-activated arenes to unactivated arenes in comparable concentrations at room temperature.
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Induced periosteum-mimicking membrane with cell barrier and multipotential stromal cell (MSC) homing functionalities
The current management of critical size bone defects (CSBDs) remains challenging and requires multiple surgeries. To reduce the number of surgeries, wrapping a biodegradable fibrous membrane around the defect to contain the graft and carry biological stimulants for repair is highly desirable. Poly(ε-caprolactone) (PCL) can be utilised to realise nonwoven fibrous barrier-like structures through free surface electrospinning (FSE). Human periosteum and induced membrane (IM) samples informed the development of an FSE membrane to support platelet lysate (PL) absorption, multipotential stromal cells (MSC) growth, and the prevention of cell migration. Although thinner than IM, periosteum presented a more mature vascular system with a significantly larger blood vessel diameter. The electrospun membrane (PCL3%-E) exhibited randomly configured nanoscale fibres that were successfully customised to introduce pores of increased diameter, without compromising tensile properties. Additional to the PL absorption and release capabilities needed for MSC attraction and growth, PCL3%-E also provided a favourable surface for the proliferation and alignment of periosteum- and bone marrow derived-MSCs, whilst possessing a barrier function to cell migration. These results demonstrate the development of a promising biodegradable barrier membrane enabling PL release and MSC colonisation, two key functionalities needed for the in situ formation of a transitional periosteum-like structure, enabling movement towards single-surgery CSBD reconstruction
Mapping the autistic advantage from the accounts of adults diagnosed with autism: A qualitative study
This is the final version. Available on open access from Mary Ann Liebert via the DOI in this recordBackground: Autism has been associated with specific cognitive strengths. Strengths and weaknesses have traditionally been conceptualized as dichotomous.
Methods: We conducted 28 semi-structured interviews with autistic adults. Maximum variation sampling was used to ensure diversity in relation to support needs. We asked which personal traits adults attributed to their autism, and how these have helped in the workplace, in relationships, and beyond. Data were collected in two stages. Responses were analyzed using content and thematic techniques.
Results: The ability to hyperfocus, attention to detail, good memory, and creativity were the most frequently described traits. Participants also described specific qualities relating to social interaction, such as honesty, loyalty, and empathy for animals or for other autistic people. In thematic analysis we found that traits associated with autism could be experienced either as advantageous or disadvantageous dependent on moderating influences. Moderating influences included the social context in which behaviors occurred, the ability to control behaviors, and the extent to which traits were expressed.
Conclusions: Separating autistic strengths from weaknesses may be a false dichotomy if traits cannot be isolated as separate constructs of strengths or deficits. If attempts to isolate problematic traits from advantageous traits are ill conceived, there may be implications for interventions that have reduction in autistic traits as a primary outcome measure.Wellcome Trus
Measuring Accuracy of Automated Parsing and Categorization Tools and Processes in Digital Investigations
This work presents a method for the measurement of the accuracy of evidential
artifact extraction and categorization tasks in digital forensic
investigations. Instead of focusing on the measurement of accuracy and errors
in the functions of digital forensic tools, this work proposes the application
of information retrieval measurement techniques that allow the incorporation of
errors introduced by tools and analysis processes. This method uses a `gold
standard' that is the collection of evidential objects determined by a digital
investigator from suspect data with an unknown ground truth. This work proposes
that the accuracy of tools and investigation processes can be evaluated
compared to the derived gold standard using common precision and recall values.
Two example case studies are presented showing the measurement of the accuracy
of automated analysis tools as compared to an in-depth analysis by an expert.
It is shown that such measurement can allow investigators to determine changes
in accuracy of their processes over time, and determine if such a change is
caused by their tools or knowledge.Comment: 17 pages, 2 appendices, 1 figure, 5th International Conference on
Digital Forensics and Cyber Crime; Digital Forensics and Cyber Crime, pp.
147-169, 201
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