Please note, due to essential maintenance online transactions will not be possible between 02:30 and 04:00 BST, on Tuesday 17th September 2019 (22:30-00:00 EDT, 17 Sep, 2019). We apologise for any inconvenience.
To send content items to your account,
please confirm that you agree to abide by our usage policies.
If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your account.
Find out more about sending content to .
To send content items to your Kindle, first ensure email@example.com
is added to your Approved Personal Document E-mail List under your Personal Document Settings
on the Manage Your Content and Devices page of your Amazon account. Then enter the ‘name’ part
of your Kindle email address below.
Find out more about sending to your Kindle.
Note you can select to send to either the @free.kindle.com or @kindle.com variations.
‘@free.kindle.com’ emails are free but can only be sent to your device when it is connected to wi-fi.
‘@kindle.com’ emails can be delivered even when you are not connected to wi-fi, but note that service fees apply.
Background: The role of extent of surgical resection (EOR) on clinical outcomes in patients with low-grade glioma requires further examination. Methods: We systematically searched MEDLINE, Embase, and the Cochrane Library for studies published between January 1, 1990 and January 5, 2018 on predefined patient outcomes regarding different EOR of low-grade glioma. Results: Our literature search yielded 60 studies including 13,289 patients. Pooled estimates of overall survival showed an increase from 3.79 years (95% CI, 2.37–5.22) in the biopsy group to 6.68 years (95% CI, 4.19–9.16) in STR to 10.65 years (95% CI, 6.78–14.52) in GTR. When compared to STR, GTR prolonged progression-free survival by 2.08 years (95% CI, 0.26–3.89; P=0.025). Pooled estimates of seizure control showed an improvement from 47.8% (95% CI, 26.7–69.6) with biopsy to 54.2% (95% CI, 48.7–59.6) with STR to 81.0% (95% CI, 74.6–86.2) with GTR. Compared to STR, GTR delayed malignant transformation (RR, 0.43; 95% CI, 0.20–0.93; P=0.032), without increasing postoperative mortality (RR, 0.38; 95% CI, 0.07–1.97; P=0.250) or morbidity (RR, 1.22; 95% CI, 0.65–2.28; P=0.540). Conclusions: Among patients with low grade gliomas, higher degrees of safe EOR, were associated with longer overall and progression-free survival, better seizure control, and delayed malignant transformation, without increased mortality or morbidity.
There is considerable research efforts aimed towards detecting disease resistance genes or QTL. If found and used in breeding programmes, such genes should reduce the likelihood and severity of epidemics. A critical question is which genes should be used and what will their impact be? Genetic epidemiological modeling techniques (MacKenzie and Bishop, 2001) can give insights into how we should prioritise the prospective resistance traits, hence candidate genes or QTL corresponding to these traits, for specific diseases. Here, a stochastic genetic epidemiological model is used to investigate the relative importance of different genetic control options and the effect of host genetic heterogeneity in controlling the transmission of a microparasitic, e.g. viral or bacterial, infection.
The redshifted 1420 MHz emission from the HI in unresolved Lyman-α clouds (DLA) at high z will appear as a background radiation in low frequency radio observations. We calculate the brightness temperature and the angular two-point correlation function of the fluctuations of this radiation. This can be an important probe of the large-scale structure at high z.
Paternal depressive symptoms are associated with children's emotional and behavioural problems, which may be mediated by negative parenting. But there is no research on the influence of paternal depressive symptoms on children's emotion regulation and limited literature investigating fathers’ parenting as a mediator in the pathway between paternal depressive symptoms and children's externalizing and internalizing problems. We aimed to investigate the mediating role of father–child conflict (at 3 years) in the association between postnatal paternal depressive symptoms (at 9 months) and children's emotional and behavioural problems (at 7 years) (aim 1). We also examined whether mediation pathways were more pronounced for boys or for girls (aim 2).
Secondary data analysis was conducted on the Millennium Cohort Study, when children were 9 months, 3 years and 7 years old (n = 3520). Main study variables were measured by self-report questionnaires. Fathers completed the Rutter Scale (depressive symptoms) and the Parent–Child Relationship Questionnaire (father–child conflict), while mothers completed the Strengths and Difficulties Questionnaire and the Social Behaviour Questionnaire (child emotional and behavioural problems, emotion regulation). We used structural equation modelling to estimate direct, indirect and total effects of paternal depressive symptoms on child outcomes, mediated by father–child conflict whilst adjusting for relevant covariates (maternal depressive symptoms, child temperament, marital conflict, and socio-economic factors such as poverty indicator and fathers’ education level). Multi-group and interaction analysis was then conducted to determine the differential effect by gender of the association between paternal depressive symptoms on child outcomes via father–child conflict.
Father–child conflict mediated the association between paternal depressive symptoms and emotion regulation problems [standardized indirect effect (SIE) 95% confidence interval (CI) −0.03 to −0.01, p < 0.001; standardized total effect (STE) 95% CI −0.05 to −0.01, p < 0.05] (aim 1). Father–child conflict mediated a larger proportion of the effect in boys (SIE 95% CI −0.03 to −0.01, p < 0.001; STE 95% CI −0.05 to 0.00, p = 0.063) than it did in girls (SIE 95% CI −0.02 to −0.01, p < 0.001; STE 95% CI −0.04 to 0.01, p = 0.216) (aim 2).
Father–child conflict may mediate the association between postnatal paternal depressive symptoms and children's emotion regulation problems. Paternal depressive symptoms and father–child conflict resolution may be potential targets in preventative interventions.
This study developed a fast and high throughput dot-blot technique to evaluate the presence of Entamoeba in stool samples (n = 643) followed by a PCR-based method to validate and differentiate the two species E. histolytica and E. dispar. The prevalence rate of the parasite has been detected in a cross-sectional study carried out in the population of the Eastern and Northern parts of India. Of the various demographic features, prevalence was highest in the monsoon season (P = 0·017), in the <15 years age group (P = 0·015). In HIV-positive individuals, the prevalence rate was significantly high (P = 0·008) in patients with a CD4 cell count <200 as well as in patients without antiretroviral therapy (ART) (P = 0·011). Our analysis further confirmed that risk factors such as toilet facilities, living conditions, hygienic practices, drinking water source, occupation and level of education are important predictors as they were found to contribute significantly in the prevalence of the parasite.
In this paper we have used the Method of Fundamental Solutions (MFS) to solve the Grad–Shafranov (GS) equation for the axisymmetric equilibria of tokamak plasmas with monomial sources. These monomials are the individual terms appearing on the right-hand side of the GS equation if one expands the nonlinear terms into polynomials. Unlike the Boundary Element Method (BEM), the MFS does not involve any singular integrals and is a meshless boundary-alone method. Its basic idea is to create a fictitious boundary around the actual physical boundary of the computational domain. This automatically removes the involvement of singular integrals. The results obtained by the MFS match well with the earlier results obtained using the BEM. The method is also applied to Solov'ev profiles and it is found that the results are in good agreement with analytical results.
A compact spectrometer-on-a-chip featuring a plasmonic molecular interaction region has been conceived, designed, modeled, and partially fabricated. The silicon-on-insulator (SOI) system is the chosen platform for the integration. The low loss of both silicon and SiO2 between 3 and 4 μm wavelengths enables silicon waveguides on SiO2 as the basis for molecular sensors at these wavelengths. Important characteristic molecular vibrations occur in this range, namely the bond stretching modes C-H (Alkynes), O-H (monomeric alcohols, phenols) and N-H (Amines), as well as CO double bonds, NH2, and CN. The device consists of a broad-band infrared LED, photonic waveguides, photon-to-plasmon transformers, a molecular interaction region, dispersive structures, and detectors. Photonic waveguide modes are adiabatically converted into SPPs on a neighboring metal surface by a tapered waveguide. The plasmonic interaction region enhances optical intensity, which allows a reduction of the overall device size without a reduction of the interaction length, in comparison to ordinary optical methods. After the SPPs propagate through the interaction region, they are converted back into photonic waveguide modes by a second taper. The dispersing region consists of a series of micro-ring resonators with photodetectors coupled to each resonator. Design parameters were optimized via electro-dynamic simulations. Fabrication was performed using a combination of photo- and electron-beam-lithography together with standard silicon processing techniques.
We have investigated the effect of nanometric grain sizes on Microstructural, electrical-, magneto-transport and magnetic behaviors in nanocrystalline Nd0.67Sr0.33MnO3 CMR manganites. Three nanocrystalline powders of Nd0.67Sr0.33MnO3 were synthesized through chemical route “Pyrophoric Reaction Process” and calcined for 5 hrs at calcinations temperature (TCal = 650°C, 750°C, and 850°C). XRD patterns indicate that all the synthesized powders have pseudo-cubic perovskite structure without any secondary impurity phase. Using Debye Scherrer formula we calculated the crystallites size for three nanocrystalline Nd0.67Sr0.33MnO3 powders (∼ 30, 40, and 54 nm for TCal = 650°C, 750°C, and 850°C respectively). TEM micrographs show that the average particle sizes are in nanometric regime (ψ ∼ 30–50 nm). In AC susceptibility and resistivity measurement we observed that there is an almost constant Curie temperature (TC) has value around 240 K and gradual decrease of metal-insulator transition temperature (TP) (from 200-129 K) with decrease of TCal. The magneto resistance of ultra fine nanoparticles increases with grain sizes. Highest magnetoresistance observed ∼ 24 for Nd0.67Sr0.33MnO3 with TCal = 850°C. Experimental results revels, the effect of nanometric grain sizes has an important impact in magnetic properties and magneto-transport behaviors.
Amorphisation of sintered SiC by bombardment with self (C, Si) ions has been studied. Ion doses ranged from 1×1015 to 1×1017 ions/cm2; and ion energy was varied from 0.09 to 5 MeV. Amorphisation was detected by micro-focus Raman scattering. Tribomechanical properties-friction and wear were studied with a high precision pin (steel ball) and disc (implanted) machine. Results show substantial improvements in friction and wear, which persist to a large number of cycles. Tribomechanical properties are shown to correlate with surface amorphisation and carburisation. Carbon ions are found to be much more effective than Si ions (with similar damage distributions) in reducing friction and wear.
Si containing stainless steels form complex oxide scales during high temperature oxidation at 900°C. These scales consist of an outer iron chromium manganese spinel layer, an intermediate Cr2O3 (chromia) layer and an inner SiO2 (silica) layer. During isothermal oxidation, alloys exhibit minimum weight gain when the inner silica layer is continuous, due to its effectiveness as a diffusion barrier. This continuous silica scale can be formed in a short time only by a combination of fine alloy grain size and high silicon content. However, formation of a continuous silica layer may lead to scale spallation on cooling, thus having a deleterious effect on the oxidation resistance of the alloy.
We report studies on La1−xSrxMnO3 /SrTiO3/ La1−xSrxMnO3 (x=0.33) trilayer junctions made using 90° off-axis sputtering. Both (110) NdGaO3 and (001) (LaAlO3)0.3-(Sr2AlTaO6)0.7 (LSAT) are used for substrates. Optical lithography is used for junction formation. These sputtered trilayers show improved junction resistance uniformity over trilayers made using laser ablation. A magnetoresistance of ∼100% is observed for junctions on LSAT with 30 Å barrier at 13 K and around 100 Oe. The shape of junction magnetoresistance vs. field depends both on barrier thickness and on substrate type, suggesting that both inter-layer coupling and substrateinduced-strain play a role in determining the junction's micromagnetic state. These results indicate better junction interfaces can be obtained for manganite trilayer junctions by 90° off-axis sputtering.
We have investigated the effect of 3d-transition metal Fe (Iron) doping at Mn site of nanometric polycrystalline La0.7Sr0.3MnO3 (i.e. La0.7Sr0.3Mn1-xFexO3; 0 ≤ x ≤ 0.1) CMR manganites on magneto-transport and magnetic properties. Nanocrystalline Fe doped La0.7Sr0.3MnO3 powders were synthesized through chemical route “Pyrophoric Reaction Process” and calcinated at 850°C for 5 hrs. X-ray diffraction (XRD) patterns of synthesized powder indicate that all samples are having perovskite structure without any secondary impurity phase. Average crystallite size was found to be 20 nm using Debye Scherer formula. Transmission electron micrographs (TEM) show that the average particle sizes are in nanometric regime (φ ˜ 50 nm) and samples are polycrystalline in nature which was observed through selected area electron diffraction (SEAD) patterns. The effect of Fe doping at Mn site of La0.7Sr0.3MnO3 was found to change substantially the magnetic and transport properties without modifying lattice structure. The suppression of magnetic and transport properties were observed due to dilution of double exchange mechanism in Mn3+- O2--Mn4+ network in La0.7Sr0.3MnO3.
To analyse the relative frequency and gender ratios in the procedures (both surgical and catheter-based interventions) performed for cardiac diseases in Indian children.
Not many studies are available in the developing countries with regard to the prevalence, relative frequency, or gender distribution of cardiac diseases in children. As universal newborn screening is not carried out for congenital cardiac diseases, the statistics are difficult to ascertain. Do female and male children with cardiac disease get equal parental preference in terms of surgical correction and catheter interventions in India? This question is also unanswered.
Analysis of 15,066 consecutive Indian children aged <18 years who were operated upon or had catheter intervention at a single tertiary care centre. Relative frequency and male/female ratios of cardiac lesions in these children were determined and compared with the studies in literature.
Overall male/female ratio in the study was 1.4:1. Ventricular septal defect was the most common lesion (24.2%) with male/female ratio of 1.5:1, followed by tetralogy of Fallot (18.7%, 1.6:1), atrial septal defect (14.4%, 0.9:1) and so on. Male children dominated the total number of procedures performed.
In most of the individual cardiac lesions, the relative frequency was different from that of international studies. The gender ratio for the majority of the individual type of cardiac problems was different from that of international references. These findings may suggest a preference for the male child in the treatment of cardiac diseases in India, which could possibly be related to social causes.
Spine gourd (Momordica dioica Roxb. ex Willd.) is a highly nutritious and underutilized vegetable containing high amount of protein as compared to other cucurbitaceous vegetables. Twenty-six accessions of spine gourd (M. dioica Roxb.), collected from eastern India, were evaluated to study the diversity and other genetic parameters. The estimates of genotypic coefficient of variation and phenotypic coefficient of variation for all the characters indicated that selection can be done on the basis of phenotype alone. On the basis of cluster analysis, spine gourd accessions can be categorized into three distinct groups. The accessions of spine gourd from eastern India showed an immense variation and can be used as a potential source of germplasm for crop improvement. The results presented here on nature and magnitude of genetic variability and diversity existing in this species will provide the foundation for designing an efficient spine gourd breeding programme. As spine gourd is distributed widely almost throughout India, further collections from Peninsular and Western India are suggested for maximum diversity sampling.
Marek’s disease (MD), caused by a herpes virus, is a very infectious, lymphoproliferative and chronic disease of poultry. Breeding for improved MD resistance poultry stock is possible since MD resistance has been associated with MHC haplotypes, QTL and candidate genes. However, integration of host genetics vis-à-vis other control strategies and the utilisation of genes or gene markers for MD in practical breeding programmes is still a challenge. The objective of the present study was to develop a basic genetic-epidemiological model for Marek’s disease infection in poultry, identify parameter spaces that describe the disease dynamics correctly and investigate the impacts of possible genetic and vaccination control strategies on overall disease dynamics.
Possible relationships between groundwater arsenic concentration and alluvial sediment characteristics in a ∼19 km2 area in West Bengal have been investigated using a combination of hydrogeochemical, lithogeochemical and geophysical techniques. Arsenic hotspots, typically associated with elevated groundwater Fe and Mn, were found to be correlated to some extent with old river channels (abandoned meanders, oxbow lakes), where sandy aquifers included intercalated fine-grained overbank deposits, rich in As, Fe, Mn and Corg. Otherwise no demonstrably significant overall differences in any of lithology, grain-size distribution, mineral composition or Fe, Mn and organic C content of the sediments were found between two representative sites with contrastingly low (<50 μg 1—1) and high (>200 μg 1—1) As groundwater contents.
Our results are consistent with microbially mediated redox reactions controlled by the presence of natural organic matter within the aquifer and the occurrence of As-bearing redox traps, primarily formed by Fe and Mn oxides/hydroxides, being the most important factors which control the release of As into shallow groundwaters at the study site.
Tropical dry forests constitute over 40% of all tropical forests (Murphy & Lugo 1986), yet their dynamics have been poorly studied relative to tropical moist forests (Bullock et al. 1995). Major ecological factors influencing the dynamics of tropical dry forests include high variability in climate, herbivory by wild mammals and domestic livestock (Skarpe 1991; Sukumar et al. 1998), natural and human-induced fires (Swain 1992; Goldammer 1993) and human extraction of a variety of products (Chopra 1993; Narendran et al. 2001). There has been much thinking on the issue of stability of tropical forests; some of this follows from or is related to the broader issue of the stability–diversity debate (e.g. Connell 1978; Pimm 1984; Lawton 1994; Johnson et al. 1996) or that of the turnover rate of tropical forests (Philips et al. 1994; Sheil 1995). These have been discussed mostly in the context of tropical moist forests.
It is being increasingly recognized that environmental variability is a major influence in shaping the structure, functioning and evolution of communities. In particular, we can expect that environmental variability would influence the evolution of life-history traits of species that constitute a particular community (e.g. Murphy 1968; Gadgil & Bossert 1970; Stearns 1977, 1992; Boyce & Daley 1980). Interannual variation in climate (e.g. precipitation) is usually taken as the most important measure of environmental variability that shapes life-history traits in a species. At the same time, the role of disturbances (e.g. hurricanes, fire) in eliciting short-term ecological responses should also be considered.
This paper describes how a computational system for designing can
learn useful, reusable, generalized search strategy rules from its own
experience of designing. It can then apply this experience to transform
the design process from search based (knowledge lean) to knowledge based
(knowledge rich). The domain of application is the design of spatial
layouts for architectural design. The processes of designing and learning
are tightly coupled.