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 firstname.lastname@example.org
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.
Semiconducting nanostructures such as nanowires (NWs) have been used as building blocks for various types of sensors, energy storage and generation devices, electronic devices and for new manufacturing methods involving printed NWs. The response of these sensing/energy/electronic components and the new fabrication methods depends very much on the quality of NWs and for this reason it is important to understand the growth mechanism of 1D semiconducting nanostructures. This is also important to understand the compatibility of NW growth steps and tools used in the process with these unconventional substrates such as plastic that are used in flexible and large area electronics. Therefore, this Element presents at length discussion about the growth mechanisms, growth conditions and the tools used for the synthesis of NWs. Although NWs from Si, ZnO and carbon nanotubes (CNTs) are included, the discussion is generic and relevant to several other types of NWs as well as heterostructures.
Parthenium hysterophorus is a prolific invasive weed species, which infests many crops in over 40 countries around the world. A 2-year field study was carried out to quantify the potential impacts of this weed on direct-seeded rice. Parthenium weed was allowed to compete for 2, 4, 6 or 8 weeks after crop emergence, while full season weedy and weed-free plots were maintained as controls. Parthenium weed plants grew taller and attained more biomass as the competition duration prolonged. The yield and yield-related attributes of rice were negatively affected with increasing competition duration. The season-long competition caused the highest reductions in panicle number (28–34%), panicle length (26–27%), grains per panicle (22–23%) and grain yield (33 and 38%) of rice in both years. Weed competition for 2–8 weeks caused 5–34% and 6–33% losses in rice grain yield during both years, respectively. Importantly, Parthenium weed control after 8 weeks of competition did not improve rice yield significantly. The results suggested that Parthenium weed should be controlled in rice fields between 4 and 8 weeks after crop emergence under direct-seeded conditions to avoid over 10% yield losses.
In recent years, the discovery of massive quasars at
has provided a striking challenge to our understanding of the origin and growth of supermassive black holes in the early Universe. Mounting observational and theoretical evidence indicates the viability of massive seeds, formed by the collapse of supermassive stars, as a progenitor model for such early, massive accreting black holes. Although considerable progress has been made in our theoretical understanding, many questions remain regarding how (and how often) such objects may form, how they live and die, and how next generation observatories may yield new insight into the origin of these primordial titans. This review focusses on our present understanding of this remarkable formation scenario, based on the discussions held at the Monash Prato Centre from November 20 to 24, 2017, during the workshop ‘Titans of the Early Universe: The Origin of the First Supermassive Black Holes’.
Goldenrods are common perennial weeds in lowbush blueberry fields in Nova Scotia. Management options are limited to mowing and suppression with POST mesotrione applications. The objectives of this research were to (1) compare efficacy of single versus sequential nonbearing-year POST mesotrione applications on goldenrod (2) identify the optimal interval between sequential POST mesotrione applications (3) evaluate nonbearing-year POST bicyclopyrone applications on goldenrod, and (4) evaluate nonbearing-year summer and fall herbicide spot treatments on goldenrod. POST mesotrione applications at 144 g ai ha−1 caused 39% to 77% injury but did not reduce goldenrod shoot density. In contrast, mesotrione applications at 144 g ai ha−1 followed by sequential mesotrione application at 14, 21, or 28 days after initial treatment caused greater than 90% injury to goldenrod and reduced both nonbearing- and bearing-year shoot density. POST bicyclopyrone applications at 50 g ai ha−1 caused 69% to 80% injury to goldenrod but did not reduce shoot density. A bicyclopyrone plus mesotrione tank mixture did not improve goldenrod control relative to mesotrione or bicyclopyrone alone. Summer spot applications of glyphosate (7.24 g ae L water−1), glufosinate (0.75 g ai L water−1), and mesotrione (0.72 g ai L water−1) consistently injured goldenrod and reduced both nonbearing- and bearing-year shoot density. Summer spot applications of bicyclopyrone (0.25 g ai L water−1), flazasulfuron (0.31 g ai L water−1), dicamba (1 g ae L water−1), dicamba plus diflufenzopyr (0.7 g ae L water−1 plus 0.3 g ai L water−1), triclopyr (1.68 g ai L water−1), clopyralid (0.08 g ai L water−1), tribenuron methyl (0.2 g ai L water−1), and foramsulfuron (0.2 g ai L water−1) injured goldenrod but did not consistently reduce shoot density. When these herbicides were evaluated as fall spot applications, only glyphosate reduced goldenrod shoot density in the year after application.
Maize (Zea mays L.) grain yield is severely constrained by drought and this study was conducted to assess gains in grain yield and other traits of released maize cultivars. Twenty-three maize cultivars plus a check were evaluated under drought and well-watered conditions at Zaria and Kadawa during 2015/2016 and 2016/2017 dry seasons. The 24 cultivars were evaluated using 6 x 4 lattice design with three replications. Genotypes differed significantly for all measured traits except anthesis-silking interval (ASI), husk cover, and number of ears per plant under drought, and ASI, husk cover, and ear aspect under well-watered conditions. Under drought, grain yield ranged from 2251 kg ha−1 for SAMMAZ 31 to 4938 kg ha−1 for SAMMAZ 19, with a genetic gain of 1.93% yr−1. Under well-watered conditions, grain yield varied from 3082 kg ha−1 for SAMMAZ 37 to 5689 kg ha−1 for SAMMAZ 51, with the same genetic gain found under drought conditions. Grain yield reduction as a result of drought was 28.4% and performance under drought predicted performance under well-watered conditions better than vice versa with regression coefficient value of 0.8. Grain yield had significant correlations with all measured traits under both water conditions, except for husk cover, plant and ear heights under drought. Our data revealed that substantial genetic gains have been made in breeding for high grain yield cultivars under drought and well-watered conditions over a period of 16 years in Nigeria.
Coeliac disease (CD) is an autoimmune gastrointestinal disorder whereby the ingestion of gluten, a storage protein found in wheat, barley and rye, causes damage to intestinal mucosa with resultant malabsorption, increased risk of anaemia and osteoporosis. Worldwide estimates suggest 1% of the population have CD. With no cure, the only treatment is a gluten-free diet (GFD). Adhering to a GFD can be very challenging; it requires knowledge, motivation and modified behaviours. Assessing adherence to a GFD is methodologically challenging. This review aims to provide an overview of the literature reporting adherence to a GFD in people with CD and the methodological challenges encountered. From six studies it has been reported that rates of adherence to a GFD range between 45 and 90% in patients of different ethnicities with CD. GF dietary adherence can be influenced by age at diagnosis, coexisting depression, symptoms on ingestion of gluten, nutrition counselling, knowledge of GF foods, understanding of food labels, cost and availability of GF foods, receiving GF foods on prescription and membership of a coeliac society. To date only five intervention studies in adults with CD have been undertaken to improve GF dietary adherence. These have included dietary and psychological counselling, and the use of online training programmes, apps, text messages and telephonic clinics. Future interventions should include people of all ethnicities, consider patient convenience and the cost-effectiveness for the healthcare environment.
The origins of agriculture in South-west Asia is a topic of continued archaeological debate. Of particular interest is how agricultural populations and practices spread inter-regionally. Was the Arabian Neolithic, for example, spread through the movement of pastoral groups, or did ideas perhaps develop independently? Here, the authors report on recent excavations at Alshabah, one of the first Neolithic sites discovered in Northern Arabia. The site’s material culture, environmental context and chronology provide evidence suggesting that well-adapted, seasonally mobile, pastoralist groups played a key role in the Neolithisation of the Arabian Peninsula.
To determine the feasibility of an anthropomorphic breast polyurethane-based three-dimensional (3D) dosimeter with cavity to measure dose distributions and skin dose for a commercial strut-based applicator strut-adjusted volume implant (SAVI™) 6–1.
Materials and methods
An anthropomorphic breast 3D dosimeter was created with a cavity to accommodate the SAVI™ strut-based device. 2 Gy was prescribed to the breast dosimeter having D95 to planning target volume evaluation (PTV_EVAL) while limiting 125% of the prescribed dose to the skin. Independent dose distribution verification was performed with GAFCHROMIC® EBT2 film. The dose distribution from the 3D dosimeter was compared to the distributions from commercial brachytherapy treatment planning system (TPS) and film. Point skin doses, line profiles and dose–volume histogram (DVHs) for the skin and PTV_EVAL were compared.
The maximum difference in skin dose for TPS and the 3D dosimeter was 4% whereas 41% between the TPS and EBT2 film. The maximum dose difference for line profiles between TPS, 3D dosimeter, and film was 4·1%. DVHs of skin and PTV_EVAL for TPS and 3D dosimeter differed by a maximum of 4% at 5 mm depth and skin differed by a maximum 1·5% between TPS and 3D dosimeter. The criterion for gamma analysis comparison was 92·5% at ±5%±3 mm criterion. The TPS demonstrated at least ±5% comparability in predicting dose to the skin, PTV_EVAL and normal breast tissue.
3D anthropomorphic polyurethane dosimeter with cavity gives comparable results to the TPS dose predictions and GAFCHROMIC® EBT2 film results in the context of HDR brachytherapy.
Accurate three-dimensional dosimetry is essential in modern radiotherapy techniques such as volumetric-modulated arc therapy (VMAT) and intensity-modulated radiation therapy (IMRT). In this research work, the PRESAGE® dosimeter was used as quality assurance (QA) tool for VMAT planning for head and neck (H&N) cancer.
Material and method
Computer tomography (CT) scans of an Image Radiation Oncology Core (IROC) H&N anthropomorphic phantom with both IROC standard insert and PRESAGE® insert were acquired separately. Both CT scans were imported into the Pinnacle (9.4 version) TPS for treatment planning, where the structures [planning target volume (PTV), organs at risk) and thermoluminescent detectors (TLDs) were manually contoured and used to optimise a VMAT plan. Treatment planning was done using VMAT (dual arc: 182°–178°, 178°–182°). Beam profile comparisons and gamma analysis were used to quantify agreement with film, PRESAGE® measurement and treatment planning system (TPS) calculated dose distribution.
The average ratio of TLD measured to calculated doses at the four PTV locations in the H&N phantom were between 0·95 to 0·99 for all three VMAT deliveries. Dose profiles were taken along the left–right, the anterior–posterior and superior–inferior axes, and good agreement was found between the PRESAGE® and Pinnacle profile. The mean value of gamma results for three VMAT deliveries in axial and sagittal planes were found to be 94·24 and 93·16% when compared with film and Pinnacle, respectively. The average values comparing the PRESAGE® results and dose values calculated on Pinnacle were observed to be 95·29 and 94·38% in the said planes, respectively, using a 5%/3 mm gamma criteria.
The PRESAGE® dose measurements and calculated dose of pinnacle show reasonable agreement in both axial and sagittal planes for complex dual arc VMAT treatment plans. In general, the PRESAGE® dosimeter is found to be a feasible QA tool of VMAT plan for H&N cancer treatment.
Violators of cooperation norms may be informally punished by their peers. How such norm enforcement is judged by others can be regarded as a meta-norm (i.e., a second-order norm). We examined whether meta-norms about peer punishment vary across cultures by having students in eight countries judge animations in which an agent who over-harvested a common resource was punished either by a single peer or by the entire peer group. Whether the punishment was retributive or restorative varied between two studies, and findings were largely consistent across these two types of punishment. Across all countries, punishment was judged as more appropriate when implemented by the entire peer group than by an individual. Differences between countries were revealed in judgments of punishers vs. non-punishers. Specifically, appraisals of punishers were relatively negative in three Western countries and Japan, and more neutral in Pakistan, UAE, Russia, and China, consistent with the influence of individualism, power distance, and/or indulgence. Our studies constitute a first step in mapping how meta-norms vary around the globe, demonstrating both cultural universals and cultural differences.
The correlation coefficient (ρ) is an important metric for the evaluation of multiple-input–multiple-output (MIMO) antenna systems because it describes the relationship between the channels in a particular propagation environment. Highly correlated channels will degrade the MIMO system performance. Various methods to calculate ρ are analyzed in this work using three different types of antennas with different efficiencies and radiating properties. While the field-based method for finding ρ gives the most accurate results and should be used all the time. It is independent of antenna efficiency. The the S-parameter-based method might give reasonable results only when the antenna efficiency is very high and the patterns are separated in space, but in most cases, it underestimates ρ values and thus is not a reliable method and should be avoided. Incorporating the antenna efficiency can improve the ρ estimates using the S-parameters method under some specific conditions. The equivalent circuit method provides reasonable results for symmetric antenna structures only, and is the most complex in formulation. As part of the evaluation, two existing methods incorporating the radiation efficiency of the antennas are generalized to N-ports for the first time. Although less accurate than the field-based method, these extensions allow the evaluation of ρ for N-port antennas using only the radiation efficiency and the S-parameters of the antenna. The effect of the beam tilts on ρ estimation is investigated for the first time.
Aerogels are a promising material for aerospace applications and have recently been explored for biomedical applications also. In both environments, exposure to radiation is inevitable, such as from radiation in space or, radiation-based sterilization and tracking of implants. X-ray radiation, in particular, is of a concern. Here, polyurea-crosslinked silica aerogel (PCSA) samples were exposed to approximately 170- and 500-Gy X-irradiation at room temperature under varying environmental conditions and characterized using electron spin resonance (ESR) technique. Results obtained for PCSA were compared with those from polyether-ether ketone (PEEK) and ultra-high molecular weight polyethylene (UHMWPE) which served as benchmarks for this study. PEEK is known to be very radiation resistant, while UHMWPE is known to be less radiation resistant. All materials (PCSA, PEEK, and UHMWPE) were exposed to the same treatments and exposure conditions. Two exposure times were tested: 10 min and 30 min which corresponded to “low” and “high” conditions, as well as comparisons of nitrogen vs. air environments during exposure and post-exposure storage. Results showed significant quantities of free radicals produced in PCSA after exposure to X-irradiation which scaled with radiation dosage; quantities were in-between those produced in PEEK and UHMWPE. The storage conditions (air vs. nitrogen) also played an important role in the free radical levels detected and are reported in this study.
The aim of this study was to investigate the socioeconomic and demographic factors influencing the body mass index (BMI) of non-pregnant married Bangladeshi women of reproductive age. Secondary (Hierarchy) data from the 2011 Bangladesh Demographic and Health Survey, collected using two-stage stratified cluster sampling, were used. Two-level linear regression analysis was performed to remove the cluster effect of the variables. The mean BMI of married non-pregnant Bangladeshi women was 21.60±3.86 kg/m2, and the prevalence of underweight, overweight and obesity was 22.8%, 14.9% and 3.2%, respectively. After removing the cluster effect, age and age at first marriage were found to be positively (p<0.01) related with BMI. Number of children was negatively related with women’s BMI. Lower BMI was especially found among women from rural areas and poor families, with an uneducated husband, with no television at home and who were currently breast-feeding. Age, total children ever born, age at first marriage, type of residence, education level, level of husband’s education, wealth index, having a television at home and practising breast-feeding were found to be important predictors for the BMI of married Bangladeshi non-pregnant women of reproductive age. This information could be used to identify sections of the Bangladeshi population that require special attention, and to develop more effective strategies to resolve the problem of malnutrition.
This paper evaluates 30-year (2013–2042) projections of the selected climatic parameters in cotton/wheat agro-climatic zone of Pakistan. A statistical bias correction procedure was adopted to eliminate the systematic errors in output of three selected general circulation models (GCM) under A2 emission scenario. A transfer function was developed between the GCM outputs and the observed time series of the climatic parameters (base period: 1980–2004) and applied to GCM future projections. The predictions detected seasonal shifts in rainfall and increasing temperature trend which in combination can affect the crop water requirements (CWR) at different phonological stages of the two major crops (i.e. wheat and cotton). CROPWAT model is used to optimize the shifts in sowing dates as a climate change adaptation option. The results depict that with reference to the existing sowing patterns, early sowing of wheat and late sowing of cotton will favour decreased CWR of these crops.
Incineration or disposal of carbon fiber waste from the aircraft industry leads to serious energy consumption and environmental pollution. The use of this waste as reinforcement is a wise approach to appreciate the high performance of the carbon fiber. In this study, the sliding wear and frictional behavior of recycled carbon fiber prepreg (rCFP) reinforced polypropylene (PP) prepared via melt compounding method using an internal mixer were studied. The samples were categorized into PP reinforced by carbon fiber with resin (A) and carbon fiber without resin (B). Pin-on-disc method was utilized to evaluate the effect of rCFP content and physical condition of fibers on tribological performance of the composites. The results were supported by morphological analyses using scanning electron microscopy. It was found that polymer composites B for rCFP without resin exhibited better tribological performance than composites category-A. The addition of rCFP into PP was observed to increase its wear resistance with minimum coefficient of friction achieved at 3 wt% of rCFP content for both polymer composites.
Infectious diseases are major constraint that hinders the poultry industry. Among them parasitic diseases are very common and Ascaridia galli is one of the most common parasitic roundworms found in poultry. Haemorrhages, diarrhoea and listlessness are signs of infection. Parasitic infections such as A. galli are treated with chemical anthelmintics (piperazine, albendazole, levamisole, Ivermectin, benzimidazoles and fenbendazole). These synthetic chemicals can promote resistance, so there is need for alternative ways to treat the disease. Medicinal plants have the potential to combat such parasitism and the development of anthelmintic resistance appears to be very slow against such treatment. This review covers the studies related to the screening of plant materials having in vitro and in vivo anthelmintic activities against A. galli throughout the world. Medicinal plants showing in vitro anthelmintic activity include Anacardium occidentale, Allium sativum, Tribulus terrestris, Bassia latifolia, Piper betle, Morinda citrifolia L.I, Cassia occidentalis L. and Aloe secundiflora while in vivo studies include the use of Psorelia corylifolia, Piper betle, Pilostigma thonningi, Caesalpinia crista, Ocimum gratissimum and Anacardium occidentale. In conclusion, medicinal plants appear to have good anthelmintic activities in poultry and may substitute conventionally used synthetic drugs, and their use may moderate drug resistance in endemic pathogen populations and drug residues in poultry meat.
The poultry industry is affected by economically important problems such as Newcastle disease (ND). Newcastle disease virus (NDV) belongs to the Paramyxoviridae family and manifests as different strains; lentogenic, mesogenic and velogenic. ND affects the quality of eggs and impairs growth performance of birds. Various efforts have been made to control economic losses due to this disease, including using live and killed vaccines, which do not confer 100% immunity in all cases. Due to mutations within viral strains, NDV can become resistant and difficult to control, and there is a need to search for alternative measures. Medicinal plants are considered as a complementary means to control this virus, especially in developing countries, because they have been implicated in treatments for a variety of infectious and non-infectious diseases. Alkaloids, flavonoids, saponins and tannins found in plants have been regarded as novel antiviral agents. The following paper encompasses the studies related to plants having in vitro antiviral activity against ND such as Momordica balamina, Adansonia digitata, Artemisia annua, Azadirachta indica, Psidium guajava, Moringa oleifera and plants having good in vivo antiviral activity such as Aloe secundiﬂora, Cucumis metuliferus and Anthocleista nobilis as well. It discusses plants with the potential to improve the immunity of infected birds, such as Mangrove halophytes, Nigella sativa, Polysavone, Melissa officinalis, Momordica cochinchinensis, Echinacea purpurea, Withania somnifera and Aspargus Racemosus.
This paper reports low temperature, digital control, fast synthesis of high-quality boron nitride nanosheets (BNNSs) and their electronic device application. Raman scattering spectroscopy, X-ray diffraction (XRD), Transmission electron microscopy (TEM) are used to characterize the BNNSs. With the synthesized various BNNSs, two prototypic types of deep UV photodetectors have been fabricated, and sensitivity, response and recovery times, as well as repeatability have been characterized. Effects of period and thickness of BNNSs on the properties of prototypic photodetectors are also discussed.
This study describes the first large-scale serosurvey on West Nile virus (WNV) conducted in the equine population in Pakistan. Sera were collected from 449 equids from two provinces of Pakistan during 2012–2013. Equine serum samples were screened using a commercial ELISA kit detecting antibodies against WNV and related flaviviruses. ELISA-positive samples were further investigated using virus-specific microneutralization tests (MNTs) to identify infections with Japanese encephalitis virus (JEV), WNV and tick-borne encephalitis virus (TBEV). Anti-WNV antibodies were detected in 292 samples by ELISA (seroprevalence 65·0%) and WNV infections were confirmed in 249 animals by MNT. However, there was no animal found infected by JEV or TBEV. The detection of WNV-seropositive equines in Pakistan strongly suggests a widespread circulation of WNV in Pakistan.