1,332 research outputs found
A new dromaeosaurid (Dinosauria: Theropoda) from the Upper Cretaceous Wulansuhai Formation of Inner Mongolia, China
We describe a new dromaeosaurid theropod from the Upper Cretaceous Wulansuhai Formation of Bayan Mandahu, Inner
Mongolia. The new taxon, Linheraptor exquisitus gen. et sp. nov., is based on an exceptionally well-preserved, nearly
complete skeleton. This specimen represents the fifth dromaeosaurid taxon recovered from the Upper Cretaceous
Djadokhta Formation and its laterally equivalent strata, which include the Wulansuhai Formation, and adds to the known
diversity of Late Cretaceous dromaeosaurids. Linheraptor exquisitus closely resembles the recently reported Tsaagan
mangas. Uniquely among dromaeosaurids, the two taxa share a large, anteriorly located maxillary fenestra and a contact
between the jugal and the squamosal that excludes the postorbital from the infratemporal fenestra. These features suggest
a sister-taxon relationship between L. exquisitus and T. mangas, which indicates the presence of a unique dromaeosaurid
lineage in the Late Cretaceous of Asia. A number of cranial and dental features seen in L. exquisitus and T. mangas, and
particularly some postcranial features of L. exquisitus, suggest that these two taxa are probably intermediate in
systematic position between known basal and derived dromaeosaurids. The discovery of Linheraptor exquisitus is thus
important for understanding the evolution of some salient features seen in the derived dromaeosaurids
Trajectories of early childhood developmental skills and early adolescent psychotic experiences: Findings from the ALSPAC UK Birth Cohort
Objective: The aim of this study was to use prospective data from the Avon Longitudinal Study of Parents and Children (ALSPAC) to examine association between trajectories of early childhood developmental skills and psychotic experiences (PEs) in early adolescence.
Method: This study examined data from n = 6790 children from the ALSPAC cohort who participated in a semi-structured interview to assess PEs at age 12. Child development was measured using parental report at 6, 18, 30, and 42 months of age using a questionnaire of items adapted from the Denver Developmental Screening Test - II. Latent class growth analysis was used to generate trajectories over time for measures of fine and gross motor development, social, and communication skills. Logistic regression was used to investigate associations between developmental trajectories in each of these early developmental domains and PEs at age 12.
Results: The results provided evidence that decline rather than enduringly poor social (adjusted OR = 1.28, 95% CI = 1.10-1.92, p = 0.044) and communication skills (adjusted OR = 1.12, 95% CI = 1.03-1.22, p = 0.010) is predictive of suspected or definite PEs in early adolescence, than those with stable and/or improving skills. Motor skills did not display the same pattern of association; although gender specific effects provided evidence that only declining pattern of fine motor skills was associated with suspected and definite PEs in males compared to females (interaction OR = 1.47, 95% CI =1.09-1.97, p = 0.012).
Conclusion: Findings suggest that decline rather than persistent impairment in social and communication skills were most predictive of PEs in early adolescence. Findings are discussed in terms of study's strengths, limitations, and clinical implications
Gravity coupled with matter and foundation of non-commutative geometry
We first exhibit in the commutative case the simple algebraic relations
between the algebra of functions on a manifold and its infinitesimal length
element . Its unitary representations correspond to Riemannian metrics and
Spin structure while is the Dirac propagator ds = \ts \!\!---\!\! \ts =
D^{-1} where is the Dirac operator. We extend these simple relations to
the non commutative case using Tomita's involution . We then write a
spectral action, the trace of a function of the length element in Planck units,
which when applied to the non commutative geometry of the Standard Model will
be shown (in a joint work with Ali Chamseddine) to give the SM Lagrangian
coupled to gravity. The internal fluctuations of the non commutative geometry
are trivial in the commutative case but yield the full bosonic sector of SM
with all correct quantum numbers in the slightly non commutative case. The
group of local gauge transformations appears spontaneously as a normal subgroup
of the diffeomorphism group.Comment: 30 pages, Plain Te
Imaging Sources with Fast and Slow Emission Components
We investigate two-proton correlation functions for reactions in which fast
dynamical and slow evaporative proton emission are both present. In such cases,
the width of the correlation peak provides the most reliable information about
the source size of the fast dynamical component. The maximum of the correlation
function is sensitive to the relative yields from the slow and fast emission
components. Numerically inverting the correlation function allows one to
accurately disentangle fast dynamical from slow evaporative emission and
extract details of the shape of the two-proton source.Comment: 13 pages, 4 figure
The <i>Plasmodium</i> eukaryotic initiation factor-2α kinase IK2 controls the latency of sporozoites in the mosquito salivary glands
Sporozoites, the invasive form of malaria parasites transmitted by mosquitoes, are quiescent while in the insect salivary glands. Sporozoites only differentiate inside of the hepatocytes of the mammalian host. We show that sporozoite latency is an active process controlled by a eukaryotic initiation factor-2α (eIF2α) kinase (IK2) and a phosphatase. IK2 activity is dominant in salivary gland sporozoites, leading to an inhibition of translation and accumulation of stalled mRNAs into granules. When sporozoites are injected into the mammalian host, an eIF2α phosphatase removes the PO4 from eIF2α-P, and the repression of translation is alleviated to permit their transformation into liver stages. In IK2 knockout sporozoites, eIF2α is not phosphorylated and the parasites transform prematurely into liver stages and lose their infectivity. Thus, to complete their life cycle, Plasmodium sporozoites exploit the mechanism that regulates stress responses in eukaryotic cells
Nonequilibrium wetting
When a nonequilibrium growing interface in the presence of a wall is
considered a nonequilibrium wetting transition may take place. This transition
can be studied trough Langevin equations or discrete growth models. In the
first case, the Kardar-Parisi-Zhang equation, which defines a very robust
universality class for nonequilibrium moving interfaces, with a soft-wall
potential is considered. While in the second, microscopic models, in the
corresponding universality class, with evaporation and deposition of particles
in the presence of hard-wall are studied. Equilibrium wetting is related to a
particular case of the problem, it corresponds to the Edwards-Wilkinson
equation with a potential in the continuum approach or to the fulfillment of
detailed balance in the microscopic models. In this review we present the
analytical and numerical methods used to investigate the problem and the very
rich behavior that is observed with them.Comment: Review, 36 pages, 16 figure
PSY59 Variation in Health-Related Quality of Life Associated With Changes in Transfusion Status of Patients With Myelodysplastic Syndromes Across Six Months of Treatment With Azacitidine
Citizen Science 2.0 : Data Management Principles to Harness the Power of the Crowd
Citizen science refers to voluntary participation by the general public in scientific endeavors. Although citizen science has a long tradition, the rise of online communities and user-generated web content has the potential to greatly expand its scope and contributions. Citizens spread across a large area will collect more information than an individual researcher can. Because citizen scientists tend to make observations about areas they know well, data are likely to be very detailed. Although the potential for engaging citizen scientists is extensive, there are challenges as well. In this paper we consider one such challenge – creating an environment in which non-experts in a scientific domain can provide appropriate and accurate data regarding their observations. We describe the problem in the context of a research project that includes the development of a website to collect citizen-generated data on the distribution of plants and animals in a geographic region. We propose an approach that can improve the quantity and quality of data collected in such projects by organizing data using instance-based data structures. Potential implications of this approach are discussed and plans for future research to validate the design are described
The PKC, HOG and Ca2+ signalling pathways co-ordinately regulate chitin synthesis in Candida albicans
Open Access via PMC2649417Peer reviewedPublisher PD
On Conformal, SL(4,R) and Sp(8,R) Symmetries of 4d Massless Fields
The invariant formulation of free field equations of massless
fields of all spins in available previously in terms of gauge invariant
field strengths is extended to gauge potentials. As a by-product, free field
equations for a massless gauge field are shown to possess both and symmetry. The proposed formulation is
well-defined in the background but experiences certain degeneracy in
the flat limit that does not allow conformal invariant field equations for spin
gauge fields in Minkowski space. The basis model involves the doubled set
of fields of all spins. It is manifestly invariant under U(1) electric-magnetic
duality extended to higher spins. Reduction to a single massless field contains
the equations that relate its electric and magnetic potentials which are mixed
by the conformal transformations for s>1. We use the unfolded formulation
approach recalled in the paper with some emphasis on the role of
Chevalley-Eilenberg cohomology of a Lie algebra in -invariant field
equations. This method makes it easy to guess a form of the 4d
invariant massless field equations and then to extend them to the ten
dimensional invariant space-time. Dynamical content of the field
equations is analyzed in terms of cohomology.Comment: 66 pages, V2: minor corrections, references and acknowledgments
added, coefficients and typos corrected, V3: typos corrected, version to
appear in Nucl. Phys.
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