1,376 research outputs found
Comment on "Wandering minds: The default network and stimulus-independent thought"
Mason et al. (Reports, 19 January 2007, p. 393) attributed activity in certain regions of the "resting" brain to the occurrence of mind-wandering. However, previous research has demonstrated the difficulty of distinguishing this type of stimulus-independent thought from stimulus-oriented thought (e.g., watchfulness). Consideration of both possibilities is required to resolve this ambiguity
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Myosin-I nomenclature.
We suggest that the vertebrate myosin-I field adopt a common nomenclature system based on the names adopted by the Human Genome Organization (HUGO). At present, the myosin-I nomenclature is very confusing; not only are several systems in use, but several different genes have been given the same name. Despite their faults, we believe that the names adopted by the HUGO nomenclature group for genome annotation are the best compromise, and we recommend universal adoption
Damage to the prefrontal cortex increases utilitarian moral judgements
The psychological and neurobiological processes underlying moral judgement have been the focus of many recent empirical studies1–11. Of central interest is whether emotions play a causal role in moral judgement, and, in parallel, how emotion-related areas of the brain contribute to moral judgement. Here we show that six patients with focal bilateral damage to the ventromedial prefrontal cortex (VMPC), a brain region necessary for the normal generation of emotions and, in particular, social emotions12–14, produce an abnor- mally ‘utilitarian’ pattern of judgements on moral dilemmas that pit compelling considerations of aggregate welfare against highly emotionally aversive behaviours (for example, having to sacrifice one person’s life to save a number of other lives)7,8. In contrast, the VMPC patients’ judgements were normal in other classes of moral dilemmas. These findings indicate that, for a selective set of moral dilemmas, the VMPC is critical for normal judgements of right and wrong. The findings support a necessary role for emotion in the generation of those judgements
Seasonal variation of water uptake of a Quercus suber tree in Central Portugal
Hydraulic redistribution (HR) is the phenomenon
where plant roots transfer water between
soil horizons of different water potential. When dry
soil is a stronger sink for water loss from the plant
than transpiration, water absorbed by roots in wetter
soil horizons is transferred toward, and exuded into
dry soil via flow reversals through the roots. Reverse
flow is a good marker of HR and can serve as a useful
tool to study it over the long-term. Seasonal variation
of water uptake of a Quercus suber tree was studied
from late winter through autumn 2003 at Rio Frio
near Lisbon, Portugal. Sap flow was measured in five
small shallow roots (diameter of 3–4 cm), 1 to 2 m
from the tree trunk and in four azimuths and at
different xylem depths at the trunk base, using the
heat field deformation method (HFD). The pattern of
sap flow differed among lateral roots as soil dried with constant positive flow in three roots and reverse
flow in two other roots during the night when
transpiration ceased. Rain modified the pattern of
flow in these two roots by eliminating reverse flow
and substantially increasing water uptake for transpiration
during the day. The increase in water uptake in
three other roots following rain was not so substantial.
In addition, the flux in individual roots was correlated
to different degrees with the flux at different radial
depths and azimuthal directions in trunk xylem. The
flow in outer trunk xylem seemed to be mostly
consistent with water movement from surface soil
horizons, whereas deep roots seemed to supply water
to the whole cross-section of sapwood. When water
flow substantially decreased in shallow lateral roots
and the outer stem xylem during drought, water flow
in the inner sapwood was maintained, presumably due
to its direct connection to deep roots. Results also
suggest the importance of the sap flow sensor
placement, in relation to sinker roots, as to whether
lateral roots might be found to exhibit reverse flow
during drought. This study is consistent with the
dimorphic rooting habit of Quercus suber trees in
which deep roots access groundwater to supply
superficial roots and the whole tree, when shallow
soil layers were dry
Complex circular subsidence structures in tephra deposited on large blocks of ice: Varða tuff cone, Öræfajökull, Iceland
Several broadly circular structures up to 16 m in diameter, into which higher strata have sagged and locally collapsed, are present in a tephra outcrop on southwest Öræfajökull, southern Iceland. The tephra was sourced in a nearby basaltic tuff cone at Varða. The structures have not previously been described in tuff cones, and they probably formed by the melting out of large buried blocks of ice emplaced during a preceding jökulhlaup that may have been triggered by a subglacial eruption within the Öræfajökull ice cap. They are named ice-melt subsidence structures, and they are analogous to kettle holes that are commonly found in proglacial sandurs and some lahars sourced in ice-clad volcanoes. The internal structure is better exposed in the Varða examples because of an absence of fluvial infilling and reworking, and erosion of the outcrop to reveal the deeper geometry. The ice-melt subsidence structures at Varða are a proxy for buried ice. They are the only known evidence for a subglacial eruption and associated jökulhlaup that created the ice blocks. The recognition of such structures elsewhere will be useful in reconstructing more complete regional volcanic histories as well as for identifying ice-proximal settings during palaeoenvironmental investigations
MFGE8 does not influence chorio-retinal homeostasis or choroidal neovascularization in vivo
Purpose: Milk fat globule-epidermal growth factor-factor VIII (MFGE8) is necessary for diurnal outer segment phagocytosis and promotes VEGF-dependent neovascularization. The prevalence of two single nucleotide polymorphisms (SNP) in MFGE8 was studied in two exsudative or “wet” Age-related Macular Degeneration (AMD) groups and two corresponding control groups. We studied the effect of MFGE8 deficiency on retinal homeostasis with age and on choroidal neovascularization (CNV) in mice.
Methods: The distribution of the SNP (rs4945 and rs1878326) of MFGE8 was analyzed in two groups of patients with “wet” AMD and their age-matched controls from Germany and France. MFGE8-expressing cells were identified in Mfge8+/− mice expressing ß-galactosidase. Aged Mfge8+/− and Mfge8−/− mice were studied by funduscopy, histology, electron microscopy, scanning electron microscopy of vascular corrosion casts of the choroid, and after laser-induced CNV.
Results: rs1878326 was associated with AMD in the French and German group. The Mfge8 promoter is highly active in photoreceptors but not in retinal pigment epithelium cells. Mfge8−/− mice did not differ from controls in terms of fundus appearance, photoreceptor cell layers, choroidal architecture or laser-induced CNV. In contrast, the Bruch's membrane (BM) was slightly but significantly thicker in Mfge8−/− mice as compared to controls.
Conclusions: Despite a reproducible minor increase of rs1878326 in AMD patients and a very modest increase in BM in Mfge8−/− mice, our data suggests that MFGE8 dysfunction does not play a critical role in the pathogenesis of AMD
Quantum Gravity in Everyday Life: General Relativity as an Effective Field Theory
This article is meant as a summary and introduction to the ideas of effective
field theory as applied to gravitational systems.
Contents:
1. Introduction
2. Effective Field Theories
3. Low-Energy Quantum Gravity
4. Explicit Quantum Calculations
5. ConclusionsComment: 56 pages, 2 figures, JHEP style, Invited review to appear in Living
Reviews of Relativit
Composite Fermion Metals from Dyon Black Holes and S-Duality
We propose that string theory in the background of dyon black holes in
four-dimensional anti-de Sitter spacetime is holographic dual to conformally
invariant composite Dirac fermion metal. By utilizing S-duality map, we show
that thermodynamic and transport properties of the black hole match with those
of composite fermion metal, exhibiting Fermi liquid-like. Built upon
Dirac-Schwinger-Zwanziger quantization condition, we argue that turning on
magnetic charges to electric black hole along the orbit of Gamma(2) subgroup of
SL(2,Z) is equivalent to attaching even unit of statistical flux quanta to
constituent fermions. Being at metallic point, the statistical magnetic flux is
interlocked to the background magnetic field. We find supporting evidences for
proposed holographic duality from study of internal energy of black hole and
probe bulk fermion motion in black hole background. They show good agreement
with ground-state energy of composite fermion metal in Thomas-Fermi
approximation and cyclotron motion of a constituent or composite fermion
excitation near Fermi-point.Comment: 30 pages, v2. 1 figure added, minor typos corrected; v3. revised
version to be published in JHE
A novel malaria vaccine candidate antigen expressed in Tetrahymena thermophila
Development of effective malaria vaccines is hampered by the problem of producing correctly folded Plasmodium proteins for use as vaccine components. We have investigated the use of a novel ciliate expression system, Tetrahymena thermophila, as a P. falciparum vaccine antigen platform. A synthetic vaccine antigen composed of N-terminal and C-terminal regions of merozoite surface protein-1 (MSP-1) was expressed in Tetrahymena thermophila. The recombinant antigen was secreted into the culture medium and purified by monoclonal antibody (mAb) affinity chromatography. The vaccine was immunogenic in MF1 mice, eliciting high antibody titers against both N- and C-terminal components. Sera from immunized animals reacted strongly with P. falciparum parasites from three antigenically different strains by immunofluorescence assays, confirming that the antibodies produced are able to recognize parasite antigens in their native form. Epitope mapping of serum reactivity with a peptide library derived from all three MSP-1 Block 2 serotypes confirmed that the MSP-1 Block 2 hybrid component of the vaccine had effectively targeted all three serotypes of this polymorphic region of MSP-1. This study has successfully demonstrated the use of Tetrahymena thermophila as a recombinant protein expression platform for the production of malaria vaccine antigens
A behavioral database for masked form priming
Reading involves a process of matching an orthographic input with stored representations in lexical memory. The masked priming paradigm has become a standard tool for investigating this process. Use of existing results from this paradigm can be limited by the precision of the data and the need for cross-experiment comparisons that lack normal experimental controls. Here, we present a single, large, high-precision, multicondition experiment to address these problems. Over 1,000 participants from 14 sites responded to 840 trials involving 28 different types of orthographically related primes (e.g., castfe–CASTLE) in a lexical decision task, as well as completing measures of spelling and vocabulary. The data were indeed highly sensitive to differences between conditions: After correction for multiple comparisons, prime type condition differences of 2.90 ms and above reached significance at the 5% level. This article presents the method of data collection and preliminary findings from these data, which included replications of the most widely agreed-upon differences between prime types, further evidence for systematic individual differences in susceptibility to priming, and new evidence regarding lexical properties associated with a target word’s susceptibility to priming. These analyses will form a basis for the use of these data in quantitative model fitting and evaluation and for future exploration of these data that will inform and motivate new experiments
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