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Gravitational waves from coalescing neutron stars encode information about nuclear matter at extreme densities, inaccessible by laboratory experiments. The late inspiral is influenced by the presence of tides, which depend on the neutron star equation of state. Neutron star mergers are expected to often produce rapidly rotating remnant neutron stars that emit gravitational waves. These will provide clues to the extremely hot post-merger environment. This signature of nuclear matter in gravitational waves contains most information in the 2–4 kHz frequency band, which is outside of the most sensitive band of current detectors. We present the design concept and science case for a Neutron Star Extreme Matter Observatory (NEMO): a gravitational-wave interferometer optimised to study nuclear physics with merging neutron stars. The concept uses high-circulating laser power, quantum squeezing, and a detector topology specifically designed to achieve the high-frequency sensitivity necessary to probe nuclear matter using gravitational waves. Above 1 kHz, the proposed strain sensitivity is comparable to full third-generation detectors at a fraction of the cost. Such sensitivity changes expected event rates for detection of post-merger remnants from approximately one per few decades with two A+ detectors to a few per year and potentially allow for the first gravitational-wave observations of supernovae, isolated neutron stars, and other exotica.
Filamentary structures can form within the beam of protons accelerated during the interaction of an intense laser pulse with an ultrathin foil target. Such behaviour is shown to be dependent upon the formation time of quasi-static magnetic field structures throughout the target volume and the extent of the rear surface proton expansion over the same period. This is observed via both numerical and experimental investigations. By controlling the intensity profile of the laser drive, via the use of two temporally separated pulses, both the initial rear surface proton expansion and magnetic field formation time can be varied, resulting in modification to the degree of filamentary structure present within the laser-driven proton beam.
A range of endophenotypes characterise psychosis, however there has been limited work understanding if and how they are inter-related.
This multi-centre study includes 8754 participants: 2212 people with a psychotic disorder, 1487 unaffected relatives of probands, and 5055 healthy controls. We investigated cognition [digit span (N = 3127), block design (N = 5491), and the Rey Auditory Verbal Learning Test (N = 3543)], electrophysiology [P300 amplitude and latency (N = 1102)], and neuroanatomy [lateral ventricular volume (N = 1721)]. We used linear regression to assess the interrelationships between endophenotypes.
The P300 amplitude and latency were not associated (regression coef. −0.06, 95% CI −0.12 to 0.01, p = 0.060), and P300 amplitude was positively associated with block design (coef. 0.19, 95% CI 0.10–0.28, p < 0.001). There was no evidence of associations between lateral ventricular volume and the other measures (all p > 0.38). All the cognitive endophenotypes were associated with each other in the expected directions (all p < 0.001). Lastly, the relationships between pairs of endophenotypes were consistent in all three participant groups, differing for some of the cognitive pairings only in the strengths of the relationships.
The P300 amplitude and latency are independent endophenotypes; the former indexing spatial visualisation and working memory, and the latter is hypothesised to index basic processing speed. Individuals with psychotic illnesses, their unaffected relatives, and healthy controls all show similar patterns of associations between endophenotypes, endorsing the theory of a continuum of psychosis liability across the population.
It has long been recognised that the Neolithic spread across Europe via two separate routes, one along the Mediterranean coasts, the other following the axis of the major rivers. But did these two streams have a common point of origin in south-west Asia, at least with regard to the principal plant and animals species that were involved? This study of barley DNA shows that the domesticated barley grown in Neolithic Europe falls into three separate types (groups A, B and C), each of which may have had a separate centre of origin in south-west Asia. Barley was relatively rarely cultivated by the early Linearbandkeramik farmers of Central and Northern Europe, but became more common during the fifth and fourth millennia BC. The analysis reported here indicates that a genetic variety of barley more suitable for northern growing conditions was introduced from south-west Asia at this period. It also suggests that the barley grown in south-eastern Europe at the very beginning of the Neolithic may have arrived there by different routes from two separate centres of domestication in south-west Asia. The multiple domestications that this pattern reveals imply that domestication may have been more a co-evolutionary process between plants and people than an intentional human action.
Comparative and functional fungal genomics
R. A. Dean, Center for Integrated Fungal Research Department of Plant Pathology 1200 Partners Building II Box 7251 North Carolina State University Raleigh NC 27695 USA,
T. Mitchell, North Carolina State University Department of Plant Pathology Campus Box 7251 Raleigh NC 27695–7251 USA,
R. Kulkarni, RTI 3040 Cornwallis Road Research Triangle Park NC 27709 USA,
N. Donofrio, North Carolina State University Department of Plant Pathology Campus Box 7251 Raleigh NC 27695–7251 USA,
A. Powell, North Carolina State University Department of Plant Pathology Campus Box 7251 Raleigh NC 27695–7251 USA,
Y. Y. Oh, North Carolina State University Department of Plant Pathology Campus Box 7251 Raleigh NC 27695–7251 USA,
S. Diener, North Carolina State University Department of Plant Pathology Campus Box 7253 Raleigh NC 27695–7253 USA,
H. Pan, RTI 3040 Cornwallis Road Research Triangle Park NC 27709 USA,
D. Brown, North Carolina State University Department of Plant Pathology Campus Box 7251 Raleigh NC 27695–7251 USA,
J. Deng, North Carolina State University Department of Plant Pathology Campus Box 7251 Raleigh NC 27695–7251 USA,
I. Carbone, North Carolina State University Department of Plant Pathology Campus Box 7244 Raleigh NC 27695–7244 USA,
D. J. Ebbole, Department of Plant Pathology and Microbiology Peterson Building Rm 120 MS# 2132 Texas A&M University College Station TX 77843–2132 USA,
M. Thon, Department of Computer Science 320C Peterson Building MS# 2132 Texas A&M University College Station TX 77843–2132 USA,
M. L. Farman, Department of Plant Pathology University of Kentucky 1405 Veterans Drive Lexington KY 40546–0312 USA,
M. J. Orbach, Department of Plant Pathology University of Arizona Forbes Room 105 PO Box 210036 Tucson AZ 85721–0036 USA,
C. Soderlund, Director of Bioinformatics Department of Plant Science 303 Forbes Building Tucson AZ 85721 USA,
J-R. Xu, Department of Botany and Plant Pathology 915 West State Street Purdue University West Lafayette IN 47906 USA,
Y-H. Lee, Seoul National University School of Agricultural Biotechnology Suwon 441–744 Korea,
N. J. Talbot, Department of Biological Sciences University of Exeter Hatherly Laboratories Prince of Wales Road Exeter EX4 4PS UK,
S. Coughlan, Agilent Technologies Inc. Little Falls Site 2850 Centerville Road Wilmington DE 19808 USA,
J. E. Galagan, The Broad Institute Massachusetts Institute of Technology 77 Massachusetts Avenue Cambridge MA 02139–4307 USA,
B. W. Birren, The Broad Institute Massachusetts Institute of Technology 77 Massachusetts Avenue Cambridge MA 02139–4307 USA
Rice blast disease, caused by the filamentous fungus Magnaporthe grisea, is a serious and recurrent problem in all rice-growing regions of the world (Talbot, 2003; Valent & Chumley, 1991). It is estimated that each year enough rice is destroyed by rice blast disease to feed 60 million people. Control of this disease is difficult; new host-specific forms develop quickly to overcome host resistance and chemical control is typically not cost effective (Ou, 1987). Infections occur when fungal spores land and attach themselves to leaves using a special adhesive released from the tip of each spore (Hamer et al., 1988). The germinating spore develops an appressorium, a specialized infection cell, which generates enormous turgor pressure – up to 8 MPa – that ruptures the leaf cuticle allowing invasion of the underlying leaf tissue (de Jong et al., 1997; Dean, 1997). Subsequent colonization of the leaf produces disease lesions from which the fungus sporulates and spreads to new plants. When rice blast infects young rice seedlings, whole plants often die, while spread of the disease to the stems, nodes or panicle of older plants results in nearly total loss of the rice grain. Recent reports have further shown that the fungus has the capacity to infect plant roots (Sesma & Osbourn, 2004). Different host-limited forms of Magnaporthe also infect a broad range of grass species including wheat, barley and millet.
The present study compared performance of children with
Attention-Deficit/Hyperactivity Disorder (ADHD) and high functioning
autism (HFA) with that of controls on 4 tasks assessing 2 components of
motor control: motor response inhibition and motor persistence. A total of
136 children (52 ADHD, 24 HFA, 60 controls) ages 7 to 13 years completed 2
measures of motor inhibition (Conflicting Motor Response and Contralateral
Motor Response Tasks) and 2 measures of motor persistence (Lateral Gaze
Fixation and NEPSY Statue). After controlling for age, IQ, gender, and
basic motor speed, children with ADHD performed significantly more poorly
than controls on the Conflicting Motor Response and Contralateral Motor
Response Tasks, as well as on Statue. In contrast, children with HFA
achieved lower scores than controls only on measures of motor persistence,
with no concomitant impairment on either motor inhibition task. These
results are consistent with prior research that has demonstrated
relatively spared motor inhibition in autism. The findings highlight the
utility of brief assessments of motor control in delineating the unique
neurobehavioral phenotypes of ADHD and HFA. (JINS, 2006,
A study of temperature dependent Hall effect (TDH), electron paramagnetic resonance (EPR), photoluminescence (PL) and secondary ion mass spectrometry (SIMS) measurements has been made on high purity semi-insulating (HPSI) 4H-SiC crystals grown by the physical vapor transport technique. Thermal activation energies from TDH varied from a low of 0.55 eV to a high of 1.5 eV. All samples studied showed n-type conduction with the Fermi level in the upper half of the band gap. Carrier concentration measurements indicated the deep levels had to be present in concentrations in the low 1015 cm-3 range. Several defects were detected by EPR including the carbon vacancy and the carbon-silicon divacancy. PL measurements in the near IR showed the presence of the UD-1, UD-2 and UD-3 emission lines that have been found in HPSI material. No correlation between the relative intensities of the PL lines and the TDH activation energies was seen. SIMS measurements on nitrogen, boron and other common impurities indicate nitrogen and boron concentrations higher than those of individual deep levels as determined by TDH or of intrinsic defects as determined by EPR such as the carbon vacancy or the divacancy. It is determined that several different defects with concentrations greater than or equal to 1x1015 cm-3 are required to compensate the residual nitrogen and boron.
It has been widely observed that thin film transistors (TFTs) incorporating an hydrogenated amorphous silicon (a-Si:H) channel exhibit a progressive shift in their threshold voltage with time upon application of a gate bias. This is attributed to the creation of metastable defects in the a-Si:H which can be removed by annealing the device at elevated temperatures with no bias applied to the gate, causing the threshold voltage to return to its original value. In this work, the defect creation and removal process has been investigated using both fully hydrogenated and fully deuterated amorphous silicon (a-Si:D) TFTs. In both cases, material was deposited by rf plasma enhanced chemical vapour deposition over a range of gas pressures to cover the a-g transition. The variation in threshold voltage as a function of gate bias stressing time, and annealing time with no gate bias, was measured. Using the thermalisation energy concept, it has been possible to quantitatively determine the distribution of energies required for defect creation and removal as well as the associated attempt-to-escape frequencies. The defect creation and removal process in a-Si:H is then discussed in the light of these results.
We describe surface preparation and epilayer growth techniques that readily reduce the density of Vf drift inducing basal plane dislocations in epilayers to less than 10 cm-2 and permit the fabrication of bipolar SiC devices with very good Vf stability. The optimal process route requires etching the substrate surface prior to epilayer growth to enhance the natural conversion of basal plane dislocations into threading edge dislocations during epilayer growth. The surface of this relatively rough “conversion” epilayer is subsequently repolished prior to growing the device structure. We provide details on processing parameters and potential problems as well as describe devices produced using this low basal plane dislocation growth processes.
The current status of SiC bulk growth is reviewed, while specific
attention is given to the effect of defects in SiC substrates and
epitaxial layers on device performance and yield. The progress in SiC
wafer quality is reflected in the achievement of micropipe densities
as low as 0.92 cm−2 for a 3-inch n-type 4H-SiC wafer, which
provides the basis for a high yielding fabrication process
of large area SiC power devices. Using a Murphy Probe Yield Analysis for the
breakdown characteristics of 10 kV PiN diodes we have extracted
an “effective” defect density for 4H-SiC material to be as low as
30 cm−2, providing valuable information to further isolate and
address the specific material defects critical for device performance.
We address the problematic degradation of the forward characteristics
(Vf-drift) of bipolar SiC PiN diodes [CITE].
The underlying mechanism due to stacking fault formation in the epitaxial
layers and possible effects of device processing are investigated.
An improved device design is demonstrated, which effectively stabilizes
this Vf-drift. We show the progression in the development of
semi-insulating SiC grown by the sublimation technique from extrinsically
doped material to high purity semi-insulating (HPSI) 4H-SiC bulk crystals of
up to 100 mm diameter without resorting to the intentional introduction
of elemental deep level dopants, such as vanadium. Uniform resistivities
in 3-inch HPSI wafers greater than 3 × 1011 Ω-cm
have been achieved. Secondary ion mass spectrometry, deep level transient
spectroscopy and electron paramagnetic resonance data suggest that the
semi-insulating behavior in HPSI material originates from deep levels
associated with intrinsic point defects. MESFETs produced on HPSI wafers
are free of backgating effects and have resulted in the best combination of
power density and efficiency reported to date for SiC MESFETs of
5.2 W/mm and 63% power added efficiency (PAE) at 3.5 GHz.
Kabuki syndrome is a dysmorphogenic syndrome which has been reported in over 300 patients since it was first described in Japan in 1981. In addition to its cardinal features (typical facies, mild-to-moderate learning disability, short stature, skeletal anomalies, and dermatoglyphic abnormalities with persistent foetal fingerpads), neurological anomalies are frequently reported, including epilepsy in 8% of those with the syndrome. We present here a 22-year-old white female patient with refractory partial epilepsy, Kabuki syndrome, and bilateral perisylvian polymicrogyria on MRI: the first reported case of this association. The aetiology of the syndrome, including the diverse genetic changes recognized, is then discussed.
Fluorescein and the 1.4 nm Nanogold® gold cluster label may be incorporated into a single Fab’ immunoprobe by separate cross-linking reactions, to give a probe which labels antigenic sites in a single step for correlative fluorescence and electron microscope visualization. These probes show high labeling density, labeling a pre-mRNA splicing factor in the HeLa cell nucleus; Microtubules were also densely labeled using fluorescence, other optical modalities, and electron microscopy; in a parallel experiment, a 5 nm colloidal gold probe gave only occasional labeling. We now describe Fab’ and streptavidin probes containing both Nanogold® and the fluorescent cyanine dye, Cy3.
F(ab’)2 Goat anti-Mouse IgG and F(ab’)2 goat anti-rabbit IgG fragments were reductively cleaved to Fab’ fragments using dithiothreitol (DTT) or mercaptoethylamine hydrochloride (MEA), which selectively reduce the F(ab’)2 hinge disulfide bonds, with 5 mm EDTA to prevent reoxidation. Fab’ fragments were isolated by gel filtration (coarse gel: GH25, Amicon) then labeled with Monomaleimido- Nanogold® which reacts site-specifically with thiols. Streptavidin was labeled using Mono- Sulfo-NHS-Nanogold® at pH 7.5. Nanogold® conjugates were isolated by gel filtration (Superose-12 column, Pharmacia), then reacted with excess Cy3 monofunctional NHS ester (labeling kit, Amersham Life Sciences) at pH 7.5; dual-labeled conjugates were isolated by gel filtration (Superose-12).
The Birmingham bone anchored hearing aid team is part of the Birmingham osseointegrated programme. In the first seven years of its existence it has received 309 referrals. Twenty-six per cent had suffered a congenital conductive hearing loss and 74 per cent had an acquired conductive hearing loss; the majority secondary to chronic suppurative otitis media.
This report is of 68 out of 106 adults wearing bone anchored hearing aids (BAHAs). Ninety-eight per cent showed audiological improvement with the congenital group demonstrating marginally the best freefield thresholds and speech discrimination. Questionnaire data as to the patient experience confirms the benefits especially hearing in noise, and comfort, and the vast majority were more satisfied with the bone anchored hearing aid than their previous aid.
Over a five-year period, 34 patients have been referred to the Birmingham bone anchored hearing aid programme, paediatric section, of whom 21 are now wearing the bone anchored hearing aid (BAHA) and four are awaiting surgery for fitting of the BAHA. Of the patients assessed, found to be suitable and who proceeded to surgery for the BAHA, 44 per cent had Treacher Collins syndrome, 28 per cent had bilateral atresia or microtia, 16 per cent had Goldenhaar's syndrome, four per cent (one patient) had branchio-oto-renal syndrome and eight per cent had chronic suppurative otitis media. This paper presents objective and subjective data collected from these patients. It is shown that the BAHA is a very effective hearing aid for children with congenital hearing loss.
Thin semiconducting films of hydrogenated amorphous silicon (a-Si:H) and its carbon alloy (a-Si:C:H) were applied to gas microstrip detectors in order to control gain instabilities due to charges on the substrate. Thin (∼100 nm) layers of a-Si:H or p-doped a-Si:C:H were placed either over or under the electrodes using the plasma enhanced chemical vapor deposition (PECVD) technique to provide the substrate with a suitable surface conductivity. By changing the carbon content and boron doping density, the sheet resistance of the a-Si:C:H coating could be successfully controlled in the range of 1012 ∼ 1017 μ/□, and the light sensitivity, which causes the resistivity to vary with ambient light conditions, was minimized. An avalanche gain of 5000 and energy resolution of 20% FWHM were achieved and the gain remained constant over a week of operation. A-Si:C:H film is an attractive alternative to ion-implanted or semiconducting glass due to the wide range of resistivities possible and the feasibility of making deposits over a large area at low cost.
The photoconductive gain mechanism in a-Si:H was investigated in connection with applications to radiation detection. Various device types such as p-i-n, n-i-n and n-i-p-i-n structures were fabricated and tested. Photoconductive gain was measured in two time scales: one for short pulses of visible light (< 1 μsec) which simulates the transit of an energetic charged particle, and the other for rather long pulses of light (1 msec) which simulates x-ray exposure in medical imaging. We used two definitions of photoconductive gain: current gain and charge gain which is an integration of the current gain. We found typical charge gains of 3 ∼ 9 for short pulses and a few hundred for long pulses at a dark current level of 10 mA/cm2. Various gain results are discussed in terms of the device structure, applied bias and dark current.