1,969 research outputs found
The fall of the Northern Unicorn::Tangential motions in the Galactic Anti-centre with SDSS and Gaia
We present the first detailed study of the behaviour of the stellar proper
motion across the entire Galactic Anti-centre area visible in the Sloan Digital
Sky Survey data. We use recalibrated SDSS astrometry in combination with
positions from {\it Gaia} DR1 to provide tangential motion measurements with a
systematic uncertainty 5 kms for the Main Sequence stars at the
distance of the Monoceros Ring. We demonstrate that Monoceros members rotate
around the Galaxy with azimuthal speeds of ~230 kms, only slightly lower
than that of the Sun. Additionally, both vertical and azimuthal components of
their motion are shown to vary considerably but gradually as a function of
Galactic longitude and latitude. The stellar over-density in the Anti-centre
region can be split into two components, the narrow, stream-like ACS and the
smooth Ring. According to our analysis, these two structures show very similar
but clearly distinct kinematic trends, which can be summarised as follows: the
amplitude of the velocity variation in and in the ACS is
higher compared to the Ring, whose velocity gradients appear to be flatter.
Currently, no model available can explain the entirety of the data in this area
of the sky. However, the new accurate kinematic map introduced here should
provide strong constraints on the genesis of the Monoceros Ring and the
associated sub-structure.Comment: Submitted to MNRAS. comments welcom
The merger that led to the formation of the Milky Way's inner stellar halo and thick disk
The assembly process of our Galaxy can be retrieved using the motions and
chemistry of individual stars. Chemo-dynamical studies of the nearby halo have
long hinted at the presence of multiple components such as streams, clumps,
duality and correlations between the stars' chemical abundances and orbital
parameters. More recently, the analysis of two large stellar surveys have
revealed the presence of a well-populated chemical elemental abundance
sequence, of two distinct sequences in the colour-magnitude diagram, and of a
prominent slightly retrograde kinematic structure all in the nearby halo, which
may trace an important accretion event experienced by the Galaxy. Here report
an analysis of the kinematics, chemistry, age and spatial distribution of stars
in a relatively large volume around the Sun that are mainly linked to two major
Galactic components, the thick disk and the stellar halo. We demonstrate that
the inner halo is dominated by debris from an object which at infall was
slightly more massive than the Small Magellanic Cloud, and which we refer to as
Gaia-Enceladus. The stars originating in Gaia-Enceladus cover nearly the full
sky, their motions reveal the presence of streams and slightly retrograde and
elongated trajectories. Hundreds of RR Lyrae stars and thirteen globular
clusters following a consistent age-metallicity relation can be associated to
Gaia-Enceladus on the basis of their orbits. With an estimated 4:1 mass-ratio,
the merger with Gaia-Enceladus must have led to the dynamical heating of the
precursor of the Galactic thick disk and therefore contributed to the formation
of this component approximately 10 Gyr ago. These findings are in line with
simulations of galaxy formation, which predict that the inner stellar halo
should be dominated by debris from just a few massive progenitors.Comment: 19 pages, 8 figures. Published in Nature in the issue of Nov. 1st,
2018. This is the authors' version before final edit
Neurodevelopmental disorders: From genetics to functional pathways
Neurodevelopmental disorders (NDDs) are a class of disorders affecting brain development and function and are characterized by wide genetic and clinical variability. In this review, we discuss the multiple factors that influence the clinical presentation of NDDs, with particular attention to gene vulnerability, mutational load, and the two-hit model. Despite the complex architecture of
mutational events associated with NDDs, the various proteins involved appear to converge on common pathways, such as synaptic plasticity/function, chromatin remodelers and the mammalian target of rapamycin (mTOR) pathway. A thorough understanding of the mechanisms behind these pathways will hopefully lead to the identification of candidates that could be targeted for treatment approaches
Increasing understanding of alien species through citizen science (Alien-CSI)
There is no sign of saturation in accumulation of alien species (AS) introductions worldwide, additionally the rate of spread for some species has also been shown to be increasing. However, the challenges of gathering information on AS are recognized. Recent developments in citizen science (CS) provide an opportunity to improve data flow and knowledge on AS while ensuring effective and high quality societal engagement with the issue of IAS (Invasive Alien Species). Advances in technology, particularly on-line recording and smartphone apps, along with the development of social media, have revolutionized CS and increased connectivity while new and innovative analysis techniques are emerging to ensure appropriate management, visualization, interpretation and use and sharing of the data. In early July 2018 we launched a European CO-operation in Science and Technology (COST) Action to address multidisciplinary research questions in relation to developing and implementing CS, advancing scientific understanding of AS dynamics while informing decision-making specifically implementation of technical requirements of relevant legislation such as the EU Regulation 1143/2014 on IAS. It will also support the EU biodiversity goals and embedding science within society. The Action will explore and document approaches to establishing a European-wide CS AS network. It will embrace relevant innovations for data gathering and reporting to support the implementation of monitoring and surveillance measures, while ensuring benefits for society and citizens, through an AS CS European network. The Action will, therefore, increase levels of participation and quality of engagement with current CS initiatives, ensuring and evaluating educational value, and improve the value outcomes for potential users including citizens, scientists, alien species managers, policy-makers, local authorities, industry and other stakeholders
Cognitive Based Design of a HMI for Telenavigation of A Space Rover
Human Machine Interface (HMI) design is a critical field of work because no general guidelines or rules have been assessed. In order to aid practitioners to design effective HMIs, different methodologies have been studied. To understand task objectives and plan goal-oriented actions, human operators exploit specific cognitive processes that have to be supported with advanced interfaces. Including cognitive aspects in HMI design allows generating an information flow that reduces user mental workload, increasing his/her situation awareness. This paper focuses on design and test of aGraphical User Interface (GUI) for the telenavigation of a space rover that makes the cognitive process of the user a priority in relation to the other development guidelines. To achieve this, a Cognitive Task Analysis (CTA) techinque, known as Applied Cognitive Work Analysis (ACWA), is combined with a multi-agent empirical test to ensure the GUI effectiveness. The ACWA allows evaluating mission scenarios, i.e. piloting the rover on the Mars surface, in order to obtain a model of the human cognitive demands that arise in these complex work domains. These demands can be used to obtain an effective information flow between the GUI and the operator. The multi-agent empirical test, on the other hand, allows an early feedback on the user mental workload aiming to validate the GUI. The result of the methodology is a GUI that eases the information flow through the interface, enhancing operator’s performance
Psychopathology and cognitive performance in individuals with membrane-associated guanylate kinase mutations: a functional network phenotyping study.
BACKGROUND: Rare pathogenic variants in membrane-associated guanylate kinase (MAGUK) genes cause intellectual disability (ID) and have recently been associated with neuropsychiatric risk in the non-ID population. However, it is not known whether risk for psychiatric symptoms amongst individuals with ID due to MAGUK gene mutations is higher than expected for the degree of general intellectual impairment, nor whether specific cognitive differences are associated with disruption to this gene functional network. METHODS: This study addresses these two questions via behavioural questionnaires and cognitive testing, applying quantitative methods previously validated in populations with ID. We compared males with X-linked ID caused by mutations in three MAGUK genes (PAK3, DLG3, OPHN1; n = 9) to males with ID caused by mutations in other X chromosome genes (n = 17). Non-parametric and parametric analyses were applied as appropriate to data. RESULTS: Groups did not differ in age, global cognitive impairment, adaptive function or epilepsy prevalence. However, individuals with MAGUK gene mutations demonstrated significantly higher psychopathology risks, comprising elevated total problem behaviours, prominent hyperactivity and elevated scores on an autism screening checklist. Despite these overt difficulties, individuals in the MAGUK group performed more accurately than expected for age and intelligence quotient (IQ) on computerised tests of visual attention, convergent with mouse models of MAGUK loss-of-function. CONCLUSIONS: Our findings support a role for MAGUK genes in influencing cognitive parameters relevant to psychiatric risk. In addition to establishing clear patterns of impairment for this group, our findings highlight the importance of careful phenotyping after genetic diagnosis, showing that gene functional network disruptions can be associated with specific psychopathological risks and cognitive differences within the context of ID.We thank all study participants and their families for extensive contributions to this project. This study was funded by the Academy of Medical Sciences/Wellcome Trust via a Starter Grant for Clinical Lecturers to KB. KB is funded by a National Institute for Health Research Academic Clinical Lectureship. GS is funded by a Wellcome Trust project grant and a James S. McDonnell Foundation Understanding Human Cognition Scholar Award. DEA is funded by an MRC UK intramural programme (MC-A0606-5PQ41). FLR is funded by the National Institute for Health Research (Cambridge Biomedical Research Centre).This is the final version of the article. It first appeared from BioMed Central via http://dx.doi.org/10.1186/s11689-015-9105-
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STXBP1 -associated neurodevelopmental disorder: a comparative study of behavioural characteristics
Abstract: Background: De novo loss of function mutations in STXBP1 are a relatively common cause of epilepsy and intellectual disability (ID). However, little is known about the types and severities of behavioural features associated with this genetic diagnosis. Methods: To address this, we collected systematic phenotyping data encompassing neurological, developmental, and behavioural characteristics. Participants were 14 individuals with STXBP1-associated neurodevelopmental disorder, ascertained from clinical genetics and neurology services UK-wide. Data was collected via standardised questionnaires administered to parents at home, supplemented by researcher observations. To isolate discriminating phenotypes, the STXBP1 group was compared to 33 individuals with pathogenic mutations in other ID-associated genes (ID group). To account for the potential impact of global cognitive impairment, a secondary comparison was made to an ability-matched subset of the ID group (low-ability ID group). Results: The STXBP1 group demonstrated impairments across all assessed domains. In comparison to the ID group, the STXBP1 group had more severe global adaptive impairments, fine motor difficulties, and hyperactivity. In comparison to the low-ability ID group, severity of receptive language and social impairments discriminated the STXBP1 group. A striking feature of the STXBP1 group, with reference to both comparison groups, was preservation of social motivation. Conclusions: De novo mutations in STXBP1 are associated with complex and variable neurodevelopmental impairments. Consistent features, which discriminate this disorder from other monogenic causes of ID, are severe language impairment and difficulties managing social interactions, despite strong social motivation. Future work could explore the physiological mechanisms linking motor, speech, and social development in this disorder. Understanding the developmental emergence of behavioural characteristics can help to focus clinical assessment and management after genetic diagnosis, with the long-term aim of improving outcomes for patients and families
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