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This chapter provides an in-depth discussion on the complexities associated with the Ex-Utero Intrapartum Therapy; EXIT procedure. The authors provide a thorough analysis of patient and procedural considerations from the maternal and fetal aspects. The perioperative approach for these procedures is reviewed in detail with respect to fetal and maternal anesthetic goals.
As a label for a distinct category of life, “living fossil” is controversial. The term has multiple definitions, and it is unclear whether the label can be genuinely used to delimit biodiversity. Even taking a purely phylogenetic perspective in which a proxy for the living fossil is evolutionary distinctness (ED), an inconsistency arises: Does it refer to “dead-end” lineages doomed to extinction or “panchronic” lineages that survive through multiple epochs? Recent tree-growth model studies indicate that speciation rates must have been unequally distributed among species in the past to produce the shape of the tree of life. Although an uneven distribution of speciation rates may create the possibility for a distinct group of living fossil lineages, such a grouping could only be considered genuine if extinction rates also show a consistent pattern, be it indicative of dead-end or panchronic lineages. To determine whether extinction rates also show an unequal distribution, we developed a tree-growth model in which the probability of speciation and extinction is a function of a tip’s ED. We simulated thousands of trees in which the ED function for a tip is randomly and independently determined for speciation and extinction rates. We find that simulations in which the most evolutionarily distinct tips have lower rates of speciation and extinction produce phylogenetic trees closest in shape to empirical trees. This implies that a distinct set of lineages with reduced rates of diversification, indicative of a panchronic definition, is required to create the shape of the tree of life.
Among the most important stimuli for developing the FLAIR multi-object spectroscopy system on the 1.2-m UK Schmidt Telescope was its potential for carrying out large-scale redshift surveys of galaxies of intermediate magnitude (B <~ 17). During FLAIR’s lengthy development period, these objects provided the yardstick by which the system’s performance was measured, and a number of limited-area redshift surveys were carried out. We are now following these with a 1-in-3 survey over the 60 fields of the ROE/Durham Galaxy Catalogue to produce a redshift map of some 4000 galaxies out to a distance of ~ 300h−1 Mpc (where the parameter h is the Hubble constant expressed as a fraction of 100 kms−1 Mpc−1). In this paper we summarise the results from our redshift surveys to highlight the capabilities of FLAIR. We present a status report on the current large-scale survey, and show that the recently-introduced FLAIR II system will speed its progress considerably.
Official suicide statistics for England are based on deaths given suicide verdicts and most cases given an open verdict following a coroner's inquest. Previous research indicates that some deaths given accidental verdicts are considered to be suicides by clinicians. Changes in coroners' use of different verdicts may bias suicide trend estimates. We investigated whether suicide trends may be over- or underestimated when they are based on deaths given suicide and open verdicts.
Possible suicides assessed by 12 English coroners in 1990/91, 1998 and 2005 and assigned open, accident/misadventure or narrative verdicts were rated by three experienced suicide researchers according to the likelihood that they were suicides. Details of all suicide verdicts given by these coroners were also recorded.
In 1990/91, 72.0% of researcher-defined suicides received a suicide verdict from the coroner, this decreased to 65.4% in 2005 (ptrend < 0.01); equivalent figures for combined suicide and open verdicts were 95.4% (1990/91) and 86.7% (2005). Researcher-defined suicides with a verdict of accident/misadventure doubled over that period, from 4.6% to 9.1% (p < 0.01). Narrative verdict cases rose from zero in 1990/91 to 25 in 2005 (4.2% of researcher-defined suicides that year). In 1998 and 2005, 50.0% of the medicine poisoning deaths given accidental/misadventure verdicts were rated as suicide by the researchers.
Between 1990/91 and 2005, the proportion of researcher-defined suicides given a suicide verdict by coroners decreased, largely due to an increased use of accident/misadventure verdicts, particularly for deaths involving poisoning. Consideration should be given to the inclusion of ‘accidental’ deaths by poisoning with medicines in the statistics available for monitoring suicides rates.
We describe three new species of fruit flies (Tephritidae: Tephritinae) (Gymnocarena defoeisp. nov. and Gymnocarenanorrbomisp. nov., from eastern North America and Gymnocarena monzonisp. nov. from Guatemala) and redescribe Gymnocarena mississippiensis Norrbom. Gymnocarena monzoni is the first Gymnocarena species to be recorded from Guatemala. This brings the total number of named species in this genus to 19. New larval host plant (Asteraceae) records for Gymnocarena include Verbesina helianthoides Michx. for G. mississippiensis and G. norrbomi, Verbesinaalternifolia (L.) Britton ex Kearney for G. norrbomi, and Viguiera cordata (Hook. and Arn.) D'Arcy for G. monzoni. The latter represents the first record for Gymnocarena in Viguiera Kunth. Gymnocarena larvae were also recorded from Verbesina virginica L. but not identified to species. A revised key to the known species of Gymnocarena and additional information on larval host plants and biology are provided.
Several theories have posited a common internalizing factor to help account for the relationship between mood and anxiety disorders. These disorders are often co-morbid and strongly covary. Other theories and data suggest that personality traits may account, at least in part, for co-morbidity between depression and anxiety. The present study examined the relationship between neuroticism and an internalizing dimension common to mood and anxiety disorders.
A sample of ethnically diverse adolescents (n=621) completed self-report and peer-report measures of neuroticism. Participants also completed the Structured Clinical Interview for DSM-IV (SCID).
Structural equation modeling showed that a single internalizing factor was common to lifetime diagnosis of mood and anxiety disorders, and this internalizing factor was strongly correlated with neuroticism. Neuroticism had a stronger correlation with an internalizing factor (r=0.98) than with a substance use factor (r=0.29). Therefore, neuroticism showed both convergent and discriminant validity.
These results provide further evidence that neuroticism is a necessary factor in structural theories of mood and anxiety disorders. In this study, the correlation between internalizing psychopathology and neuroticism approached 1.0, suggesting that neuroticism may be the core of internalizing psychopathology. Future studies are needed to examine this possibility in other populations, and to replicate our findings.
The design of metals and alloys resistant to radiation damage involves the physics of
electronic excitations and the creation of defects and microstructure. During irradiation damage of metals by high energy particles, energy is exchanged between ions and electrons. Such “non-adiabatic” processes violate the Born-Oppenheimer approximation, on which all conservative classical interatomic potentials rest. By treating the electrons of a metal explicitly and quantum mechanically we are able to explore the influence of electronic excitations on the ionic motion during irradiation damage. Simple theories suggest that moving ions should feel a damping force proportional to their velocity and directly opposed to it. In contrast, our simulations of a forced oscillating ion have revealed the full complexity of this force: in reality it is anisotropic and dependent on the ion velocity and local atomic environment. A large set of collision cascade simulations has allowed us to explore the form of the damping force further. We have a means of testing various schemes in the literature for incorporating such a force within molecular dynamics (MD) against our semi-classical evolution with explicitly modelled electrons. We find that a model in which the damping force is dependent upon the local electron density is superior to a simple fixed damping model. We also find that applying a lower kinetic energy cut-off for the damping force results in a worse model. A detailed examination of the nature of the forces reveals that there is much scope for further improving the electronic force models within MD.
Altered functioning of the hypothalamic–pituitary–adrenal (HPA) axis is a robust correlate of major depression in adults, and to a lesser extent, in adolescents. Premorbid differences in HPA axis function have been found to prospectively predict the onset of adolescent depression. To what extent might our knowledge of HPA axis function in adolescents with, or at risk for, depression, help guide efforts to prevent depression in this age group? We review evidence regarding the role of the HPA axis in the development of adolescent depression, and examine whether and which HPA axis measures might be useful in guiding prevention efforts as (a) as a criterion by which to select youth at risk for depression, (b) as a predictor of which youth will be most responsive to prevention efforts, and (c) as an indicator of whether prevention/intervention efforts are working. We conclude that our current understanding of the HPA axis, and its measurement, in adolescent depression are not sufficiently precise to be of immediate practical use in improving prevention efforts. Incorporating HPA axis measures into prevention studies, however, would be immensely useful in clarifying the role of the HPA axis in adolescent depression, such that future prevention efforts might more confidently rely on HPA axis information.
Intraspecific genetic variation may contribute significantly to invasiveness and control problems, but has been characterized to date in relatively few invasive weed species. We examined 56 intersimple sequence repeat (ISSR) loci in 220 individuals from 11 invading populations of yellow toadflax sampled across five western states. All populations showed high levels of genetic diversity. Estimated values for Shannon's diversity measure ranged from 0.217 to 0.388, and for expected heterozygosity from 0.178 to 0.260. Nei's total gene diversity index (HT), on the basis of all individuals across all populations, was 0.267. Partitioning of genetic variance using analysis of molecular variance revealed 1.7% of genetic variation among regional population groups, 29.1% among populations within groups, and 69.2% within populations, consistent with expectations for an outcrossing species but suggesting little geographic differentiation. Pairs of adjacent individuals identical at all ISSR loci that appeared to be ramets of a single clone were detected in only one population. This indicates that patch expansion in yellow toadflax is driven more by sexual reproduction via seed than by rhizomatous clonal spread, at least at the spatial scale of sampling for this study. Eight populations had significant values for Mantel's R at P = 0.05, suggesting some fine-scale positive genetic structuring, possibly from restricted gene flow. Population clustering on the basis of Nei's genetic distance between populations and unweighted pair group method with arithmetic mean did not reflect geographic location. It is likely that multiple introductions of this species have occurred across the Intermountain West, followed by extensive genetic recombination. High levels of genetic diversity within yellow toadflax populations pose management challenges, as already seen in reports of variable response to herbicide application and limited impacts of biocontrol agent releases.
We consider the reinterpretation of Bethia by Bassett et al. (2008) to be flawed in several regards. Details of the pedicle rootlets and wrinkles strongly imply a soft-tissue structure rather than calcified sheath. The ornament is unusual, but equally so under either an orthide or a plectambonitoidean model. The reinterpretation of the ‘deltial plates’ as ‘chilidial plates’ is likely correct, but argues against a plectambonitoidean affinity by implying that the pedicle emerges between the valves. Other arguments presented in favour of a plectambonitoidean affinity are also discussed; we consider them unpersuasive. Finally, we contend that Bethia is sufficiently well characterised to deserve a taxonomic name.
Covering an area of 177,000 hectares, the region known within Belize as the Chiquibul Forest comprises the country's largest forest reserve and includes the Chiquibul Forest Reserve, the Chiquibul National Park and the Caracol Archaeological Reserve. Based on 7047 herbarium and live collections, a checklist of 1355 species of vascular plant is presented for this area, of which 87 species are believed to be new records for the country. Of the 41 species of plant known to be endemic to Belize, four have been recorded within the Chiquibul, and 12 species are listed in The World Conservation Union (IUCN) 2006 Red List of Threatened Species. Although the Chiquibul Forest has been relatively well collected, there are geographical biases in botanical sampling which have focused historically primarily on the limestone forests of the Chiquibul Forest Reserve. A brief review of the collecting history of the Chiquibul is provided, and recommendations are given on where future collecting efforts may best be focused. The Chiquibul Forest is shown to be a significant regional centre of plant diversity and an important component of the Mesoamerican Biological Corridor.
A vaccination programme offering hepatitis B (HBV) vaccine at reception into prison has been introduced into selected prisons in England and Wales. Over the coming years it is anticipated this vaccination programme will be extended. A model has been developed to assess the potential impact of the programme on the vaccination coverage of prisoners, ex-prisoners, and injecting drug users (IDUs). Under a range of coverage scenarios, the model predicts the change over time in the vaccination status of new entrants to prison, current prisoners and IDUs in the community. The model predicts that at baseline in 2012 57% of the IDU population will be vaccinated with up to 72% being vaccinated depending on the vaccination scenario implemented. These results are sensitive to the size of the IDU population in England and Wales and the average time served by an IDU during each prison visit. IDUs that do not receive HBV vaccine in the community are at increased risk from HBV infection. The HBV vaccination programme in prisons is an effective way of vaccinating this hard-to-reach population although vaccination coverage on prison reception must be increased to achieve this.
Optimization of GaN channel conductivity in AlGaN/GaN Heterojunction Field Effect Transistor (HFET) structures was performed using High Resistivity (HR) GaN templates grown by Metal-organic Vapor Phase Epitaxy (MOVPE). The GaN sheet resistance was tuned using final nucleation layer (NL) annealing temperature. Using an annealing temperature of 1033°C, GaN with sheet resistance of 10 Ω/sq was achieved, comparable to that of Fe-doped GaN. X-Ray Diffraction (XRD) and Photoluminescence (PL) analysis show that the high resistance GaN is achieved due to compensating acceptor levels introduced through edge-type threading dislocations. XRD analysis also shows optimization of annealing temperature provided a means to maximize GaN sheet resistance without significantly degrading material quality. AlGaN/GaN HFET layers grown using HR GaN templates gave surface and interface roughness of 14 and 7 Å, respectively. The 2DEG Hall mobility and sheet charge of HFETs grown using HR GaN templates was comparable to similar layers grown using unintentionally doped (UID) GaN templates.