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High-energy and high-intensity lasers are essential for pushing the boundaries of science. Their development has allowed leaps forward in basic research areas, including laser–plasma interaction, high-energy density science, metrology, biology and medical technology. The Helmholtz International Beamline for Extreme Fields user consortium contributes and operates two high-peak-power optical lasers using the high energy density instrument at the European X-ray free electron laser (EuXFEL) facility. These lasers will be used to generate transient extreme states of density and temperature to be probed by the X-ray beam. This paper introduces the ReLaX laser, a short-pulse high-intensity Ti:Sa laser system, and discusses its characteristics as available for user experiments. It will also present the first experimental commissioning results validating its successful integration into the EuXFEL infrastructure and viability as a relativistic-intensity laser driver.
White matter (WM) impairments have been reported in patients with bipolar disorder (BD) and those at high familial risk of developing BD. However, the distribution of these impairments has not been well characterized. Few studies have examined WM integrity in young people early in the course of illness and in individuals at familial risk who have not yet passed the peak age of onset.
WM integrity was examined in 63 BD subjects, 150 high-risk (HR) individuals and 111 participants with no family history of mental illness (CON). All subjects were aged 12 to 30 years.
This young BD group had significantly lower fractional anisotropy within the genu of the corpus callosum (CC) compared with the CON and HR groups. Moreover, the abnormality in the genu of the CC was also present in HR participants with recurrent major depressive disorder (MDD) (n = 16) compared with CON participants.
Our findings provide important validation of interhemispheric abnormalities in BD patients. The novel finding in HR subjects with recurrent MDD – a group at particular risk of future hypo/manic episodes – suggests that this may potentially represent a trait marker for BD, though this will need to be confirmed in longitudinal follow-up studies.
This paper presents the design and science goals for the SkyMapper telescope. SkyMapper is a 1.3-m telescope featuring a 5.7-square-degree field-of-view Cassegrain imager commissioned for the Australian National University's Research School of Astronomy and Astrophysics. It is located at Siding Spring Observatory, Coonabarabran, NSW, Australia and will see first light in late 2007.
The imager possesses 16 384 × 16 384 0.5-arcsec pixels. The primary scientific goal of the facility is to perform the Southern Sky Survey, a six-colour and multi-epoch (four-hour, one-day, one-week, one-month and one-year sampling) photometric survey of the southerly 2π sr to g ∼23 mag. The survey will provide photometry to better than 3% global accuracy and astrometry to better than 50 milliarcsec. Data will be supplied to the community as part of the Virtual Observatory effort. The survey will take five years to complete.
We are developing a purely commensal survey experiment for fast (<5 s) transient radio sources. Short-timescale transients are associated with the most energetic and brightest single events in the Universe. Our objective is to cover the enormous volume of transients parameter space made available by ASKAP, with an unprecedented combination of sensitivity and field of view. Fast timescale transients open new vistas on the physics of high brightness temperature emission, extreme states of matter and the physics of strong gravitational fields. In addition, the detection of extragalactic objects affords us an entirely new and extremely sensitive probe on the huge reservoir of baryons present in the IGM. We outline here our approach to the considerable challenge involved in detecting fast transients, particularly the development of hardware fast enough to dedisperse and search the ASKAP data stream at or near real-time rates. Through CRAFT, ASKAP will provide the testbed of many of the key technologies and survey modes proposed for high time resolution science with the SKA.
We present experimental results supporting physics-based ejecta model development, where our main assumption is that ejecta form as a special limiting case of a Richtmyer–Meshkov (RM) instability at a metal–vacuum interface. From this assumption, we test established theory of unstable spike and bubble growth rates, rates that link to the wavelength and amplitudes of surface perturbations. We evaluate the rate theory through novel application of modern laser Doppler velocimetry (LDV) techniques, where we coincidentally measure bubble and spike velocities from explosively shocked solid and liquid metals with a single LDV probe. We also explore the relationship of ejecta formation from a solid material to the plastic flow stress it experiences at high-strain rates () and high strains (700 %) as the fundamental link to the onset of ejecta formation. Our experimental observations allow us to approximate the strength of Cu at high strains and strain rates, revealing a unique diagnostic method for use at these extreme conditions.
Public figures are at increased risk of attracting unwanted attention in the form of intrusions, stalking and, occasionally, attack. Whereas the potential threat to the British Royal Family from terrorists and organized groups is clearly defined, there is a dearth of knowledge about that from individual harassers and stalkers. This paper reports findings from the first systematic study of this group.
A retrospective study was conducted of a randomly selected stratified sample (n=275) of 8001 files compiled by the Metropolitan Police Service's Royalty Protection Unit over 15 years on inappropriate communications or approaches to members of the British Royal Family. Cases were split into behavioural types. Evidence of major mental illness was recorded from the files. Cases were classified according to a motivational typology. An analysis was undertaken of associations between motivation, type of behaviour and mental illness.
Of the study sample, 83.6% were suffering from serious mental illness. Different forms of behaviour were associated with different patterns of symptomatology. Cases could be separated into eight motivational groups, which also showed significant differences in mental state. Marked differences in the intrusiveness of behaviour were found between motivational groups.
The high prevalence of mental illness indicates the relevance of psychiatric intervention. This would serve the health interests of psychotic individuals and alleviate protection concerns without the necessity of attempting large numbers of individual risk predictions. The finding that some motivations are more likely to drive intrusive behaviours than others may help focus both health and protection interventions.
When in its life should an individual first attempt to reproduce? How often should it breed thereafter? How much effort should it invest in each attempt? And does this vary between individuals in the same population? These questions are central to the many studies investigating adaptive life-history strategies, across the taxonomic spectrum, yet detailed answers are provided by few, particularly in large, free-ranging species. This is because comprehensive data on the costs and benefits of reproduction throughout life are essential for the task, but are difficult to collect in the wild, especially for males in polygynous species. With Soay sheep, however, we have the detailed information with which to investigate the reproductive benefits and costs for both sexes, and the way these vary with the environment and individual phenotype.
In Soays, the costs and benefits of reproduction take on even greater significance given the domestic roots of the population. A brief examination of the Soay life-history reveals unusual patterns that have led many to question whether these are simply the maladaptive legacy of past domestication. Soays certainly bear the hallmarks of artificial selection for high productivity (Chapter 1). Both sexes, but particularly males, mature early (Fig. 9.1) despite incurring high survival costs; and females continue to display fatally high fecundity at peak population densities (Chapter 2). These costs suggest that Soays are too fecund for their own good. Yet it remains possible that these are not the result of domestication, but are adaptive responses to their environment.
The ALFA mission is designed to map the entire sky at frequencies between approximately 0.3 and 30 MHz with angular resolution limited by interstellar and interplanetary scattering. Most of this region of the spectrum is inaccessible from the ground because of absorption and refraction by the Earth’s ionosphere. A wide range of astrophysical questions concerning solar system, galactic, and extragalactic objects could be answered with high resolution images at low frequencies, where absorption effects and coherent emission processes become important and the synchrotron lifetimes of electrons are comparable to the age of the universe.
With new 6 cm observations we confirm the self-similar expansion of SN 1993J previously discovered at 3.6 cm and estimate the expansion deceleration parameter. The results are inconsistent with the existence of a constant pre-explosion stellar wind but otherwise confirm the standard radio supernova model. The first map at 13 cm showing shell structure is also presented.
We determine the relative separations of the sources in the triangle 1803+784/1928+738/2007+777 with submilliarcsecond accuracy from global 8.4 GHz VLBI observations. We remove the ionospheric contribution to the phase-delay observable using ionospheric total electron content estimates obtained from Global Positioning System (GPS) data. The triangular geometry provides a consistency check through sky closure.
The snail Bulinus nasutus 1214 possesses a potent haemagglutinin (end-point titre with human erythrocytes, 2−18) in its cell-free haemolymph which also binds to the miracidia (but not other larvae) of the incompatible parasite Schistosoma margrebowiei. We have purified a protein possessing this haemagglutinating property from the plasma of this snail. The native Mr of this protein was estimated by SDS polyacrylamide gel electrophoresis to be 210 kDa; under denaturing conditions in a 7.5% PAGE gel it ran as a major band of 135 kDa. Proteins of similar Mr were also found in the haemolymph of 16 other Bulinus spp. (the major intermediate hosts of human and veterinary schistosomiasis in Africa) although the plasma of none of these agglutinated human erythrocytes. Nonetheless, Cleveland mapping of the Mr 135 kDa bands from these different Bulinus spp. revealed 4 identical major peptide fragments (30, 28, 19 and 16 kDa) in each, thus demonstrating a similarity in the primary structure of these plasma proteins. Antisera from Balb/C mice immunized with the 135 kDa polypeptide from Bulinus truncatus 1521 cross-reacted in Western blots with the 135 kDa band of other members of the same truncatus/tropicus species complex but not with species from the africanus or forskalii species groups.
The in vitro transformation of the miracidium to the mother sporocyst of Schistosoma margrebowiei was initiated by placing the miracidium in mammalian physiological saline. The transformation occurs in stages: the cilia cease beating; the ciliated plates become detached from the intercellular ridges and underlying muscle layers; the intercellular ridges spread over the body surface eventually forming a new tegument; the sporocyst changes from an ovoid to a tubular shape in about 48 h at room temperature. The surfaces of the miracidium, sporocyst and cercaria of S. margrebowiei display stage-specific carbohydrates on their surfaces as indicated by lectin staining. Ricin120 stains the cilia alone of the miracidium whereas peanut agglutinin stains the larval surface except for the cilia. The intercellular ridges of the miracidium stain with concanavalin A and wheat germ agglutinin, and these lectins stain the entire surface of the mature mother sporocyst. The cercaria is the only larval stage which stains positively with asparagus pea lectin. Bulinus nasutus is incompatible with Schistosoma margrebowiei; the haemolymph of this snail contains an agglutinin which agglutinates a wide variety of mammalian erythrocytes including those of human ABO blood groups. The haemagglutinin titre of B. nasutus plasma is reduced after incubation with miracidia of S. margrebowiei indicating that the agglutinin is absorbed onto the surface of this larval stage but not that of the mother sporocyst or cercaria. The possible roles of agglutinins in host–parasite interactions together with the significance of the differences in the surface carbohydrates of the larval stages are discussed.
Almost all attempts to improve animal production systems in developing countries have failed because they relied on the transfer of technologies from developed countries. Livestock production systems in industrialized conuntries have high rates of animal productivity, which at the same time require high quality feeds, rich in energy and protein. Most developed countries are located in temperate climates in which cereals and high quality feeds and grains can be readily grown and have the currency to provide all the fossil fuel inputs required.
In order for Third World countries, located mostly in tropical regions, to adapt these systems, they must import exotic livestock and provide the high level of feeding at high cost. The transferred system has led to a loss of interest in indigenous breeds and local resources.
It is clear that there is a great need for new rural development strategies that should take into account not only food production but also renewable energy resources, employment generation, self reliance and protection of the enviroment. This strategy includes selection of crops and cropping systems which maximize biomass production, nitrogen fixation and minimize the use of imported or expensive inputs.