1,673 research outputs found

    Discovery of a transient radiation belt at Saturn

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    Radiation belts have been detected in situ at five planets. Only at Earth however has any variability in their intensity been heretofore observed, in indirect response to solar eruptions and high altitude nuclear explosions. The Cassini spacecraft's MIMI/LEMMS instrument has now detected systematic radiation belt variability elsewhere. We report three sudden increases in energetic ion intensity around Saturn, in the vicinity of the moons Dione and Tethys, each lasting for several weeks, in response to interplanetary events caused by solar eruptions. However, the intensifications, which could create temporary satellite atmospheres at the aforementioned moons, were sharply restricted outside the orbit of Tethys. Unlike Earth, Saturn has almost unchanging inner ion radiation belts: due to Saturn's near-symmetrical magnetic field, Tethys and Dione inhibit inward radial transport of energetic ions, shielding the planet's main, inner radiation belt from solar wind influences

    Determination of the absorption coefficient of chromophoric dissolved organic matter from underway spectrophotometry

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    Measurements of the absorption coefficient of chromophoric dissolved organic matter (ay) are needed to validate existing ocean-color algorithms. In the surface open ocean, these measurements are challenging because of low ay values. Yet, existing global datasets demonstrate that ay could contribute between 30% to 50% of the total absorption budget in the 400–450 nm spectral range, thus making accurate measurement of ay essential to constrain these uncertainties. In this study, we present a simple way of determining ay using a commercially-available in-situ spectrophotometer operated in underway mode. The obtained ay values were validated using independent collocated measurements. The method is simple to implement, can provide measurements with very high spatio-temporal resolution, and has an accuracy of about 0.0004 m−1 and a precision of about 0.0025 m−1 when compared to independent data (at 440 nm). The only limitation for using this method at sea is that it relies on the availability of relatively large volumes of ultrapure water. Despite this limitation, the method can deliver the ay data needed for validating and assessing uncertainties in ocean-colour algorithms

    Chromosomal-level assembly of the Asian Seabass genome using long sequence reads and multi-layered scaffolding

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    We report here the ~670 Mb genome assembly of the Asian seabass (Lates calcarifer), a tropical marine teleost. We used long-read sequencing augmented by transcriptomics, optical and genetic mapping along with shared synteny from closely related fish species to derive a chromosome-level assembly with a contig N50 size over 1 Mb and scaffold N50 size over 25 Mb that span ~90% of the genome. The population structure of L. calcarifer species complex was analyzed by re-sequencing 61 individuals representing various regions across the species' native range. SNP analyses identified high levels of genetic diversity and confirmed earlier indications of a population stratification comprising three clades with signs of admixture apparent in the South-East Asian population. The quality of the Asian seabass genome assembly far exceeds that of any other fish species, and will serve as a new standard for fish genomics

    Relational persons and relational processes: developing the notion of relationality for the sociology of personal life

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    The concept of relationality has recently found widespread favour in British sociology, particularly in the emergent sub-field of the sociology of personal life, which is characterised by its attachment to the concept. However, this ‘relational turn’ is under-theorized and pays little attention to the substantial history of relational thinking across the human sciences. This paper argues that the notion of relationality in the sociology of personal life might be strengthened by an exploration of the conceptualization of the relational person and relational processes offered by three bodies of literature: the process oriented thinking of American pragmatism, specifically of Mead and Emirbayer; the figurational sociology of Elias; and psychoanalysis, particularly the object relations tradition, contemporary relational psychoanalysis and Ettinger’s notion of transubjectivity. The paper attends particularly to the processes involved in the individuality, agentic reflexivity and affective dimensions of the relational person

    Two novel human cytomegalovirus NK cell evasion functions target MICA for lysosomal degradation

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    NKG2D plays a major role in controlling immune responses through the regulation of natural killer (NK) cells, αβ and γδ T-cell function. This activating receptor recognizes eight distinct ligands (the MHC Class I polypeptide-related sequences (MIC) A andB, and UL16-binding proteins (ULBP)1–6) induced by cellular stress to promote recognition cells perturbed by malignant transformation or microbial infection. Studies into human cytomegalovirus (HCMV) have aided both the identification and characterization of NKG2D ligands (NKG2DLs). HCMV immediate early (IE) gene up regulates NKGDLs, and we now describe the differential activation of ULBP2 and MICA/B by IE1 and IE2 respectively. Despite activation by IE functions, HCMV effectively suppressed cell surface expression of NKGDLs through both the early and late phases of infection. The immune evasion functions UL16, UL142, and microRNA(miR)-UL112 are known to target NKG2DLs. While infection with a UL16 deletion mutant caused the expected increase in MICB and ULBP2 cell surface expression, deletion of UL142 did not have a similar impact on its target, MICA. We therefore performed a systematic screen of the viral genome to search of addition functions that targeted MICA. US18 and US20 were identified as novel NK cell evasion functions capable of acting independently to promote MICA degradation by lysosomal degradation. The most dramatic effect on MICA expression was achieved when US18 and US20 acted in concert. US18 and US20 are the first members of the US12 gene family to have been assigned a function. The US12 family has 10 members encoded sequentially through US12–US21; a genetic arrangement, which is suggestive of an ‘accordion’ expansion of an ancestral gene in response to a selective pressure. This expansion must have be an ancient event as the whole family is conserved across simian cytomegaloviruses from old world monkeys. The evolutionary benefit bestowed by the combinatorial effect of US18 and US20 on MICA may have contributed to sustaining the US12 gene family

    Moving out of the shadows: accomplishing bisexual motherhood

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    Our qualitative study explored the ways in which bisexual mothers came to identify as such and how they structured their relationships and parenting within hetero-patriarchal society. The experiences of seven self-identified White bisexual women (aged from 28 to 56-years-old) from across England and the Republic of Ireland were investigated through semi-structured interviews. Participants’ children were aged 8 months to 28 years old at the time of their interviews. A thematic narrative analysis highlighted the following issues that participants had encountered in constructing their self-identity: prioritizing children; connecting and disconnecting with others and finessing self-definition; questioning societal relationship expectations. Nevertheless, participants varied considerably in how each of the themes identified were reflected in their lives, in particular depending upon each participant’s interpretation of her local social context. Both motherhood and self-identifying as bisexual gave a sense of meaning and purpose to participants’ life stories, although participants sometimes foregrounded their commitment to their children even at a personal cost to their bisexual identity. Using three different theoretical perspectives from feminist theory, queer theory and life course theory, the narratives analysed revealed ways in which bisexual motherhood not only had been influenced both intentionally and unintentionally by heteronormative expectations but also had directly and indirectly challenged these expectations

    Gender differences in the impact of family background on leaving the parental home

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    We address the question to what extent characteristics of the family of origin influence the timing of leaving the parental home and to what extent these effects differ between men and women. We use data from the Netherlands Kinship Panel Study to examine the effects of parental resources, atmosphere in the family of origin and family structure on leaving home to live without a partner and leaving home to live with a partner. The results indicate that a pleasant atmosphere in the parental home decreases the risk of leaving home and living in stepfamilies or single-parent families increases this risk. The availability of parental resources leads to a decreased risk of leaving home at young ages, but an increased risk at later ages. Many of these effects are found for both men and women and for both pathways out of the home. Furthermore, we find evidence that women are affected more strongly by family background characteristics than men are

    Extragalactic Radio Continuum Surveys and the Transformation of Radio Astronomy

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    Next-generation radio surveys are about to transform radio astronomy by discovering and studying tens of millions of previously unknown radio sources. These surveys will provide new insights to understand the evolution of galaxies, measuring the evolution of the cosmic star formation rate, and rivalling traditional techniques in the measurement of fundamental cosmological parameters. By observing a new volume of observational parameter space, they are also likely to discover unexpected new phenomena. This review traces the evolution of extragalactic radio continuum surveys from the earliest days of radio astronomy to the present, and identifies the challenges that must be overcome to achieve this transformational change.Comment: To be published in Nature Astronomy 18 Sept 201
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