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.
Irradiation of reactor pressure vessel (RPV) steels causes the formation of nanoscale microstructural features (termed radiation damage), which affect the mechanical properties of the vessel. A key tool for characterizing these nanoscale features is atom probe tomography (APT), due to its high spatial resolution and the ability to identify different chemical species in three dimensions. Microstructural observations using APT can underpin development of a mechanistic understanding of defect formation. However, with atom probe analyses there are currently multiple methods for analyzing the data. This can result in inconsistencies between results obtained from different researchers and unnecessary scatter when combining data from multiple sources. This makes interpretation of results more complex and calibration of radiation damage models challenging. In this work simulations of a range of different microstructures are used to directly compare different cluster analysis algorithms and identify their strengths and weaknesses.
Poor effortful control is a key temperamental factor underlying behavioral problems. The bidirectional association of child effortful control with both positive parenting and negative discipline was examined from ages approximately 3 to 13–14 years, involving five time points, and using data from parents and children in the Oregon Youth Study—Three Generational Study (N = 318 children from 150 families). Based on a dynamic developmental systems approach, it was hypothesized that there would be concurrent associations between parenting and child effortful control and bidirectional effects across time from each aspect of parenting to effortful control and from effortful control to each aspect of parenting. It was also hypothesized that associations would be more robust in early childhood, from ages 3 to 7 years, and would diminish as indicated by significantly weaker effects at the older ages, 11–12 to 13–14 years. Longitudinal feedback or mediated effects were also tested. The findings supported (a) stability in each construct over multiple developmental periods; (b) concurrent associations, which were significantly weaker at the older ages; (c) bidirectional effects, consistent with the interpretation that at younger ages children's effortful control influenced parenting, whereas at older child ages, parenting influenced effortful control; and (d) a transactional effect, such that maternal parenting in late childhood was a mechanism explaining children's development of effortful control from middle childhood to early adolescence.
This paper briefly describes the principle of operation and science goals of the AMANDA high energy neutrino telescope located at the South Pole, Antarctica. Results from an earlier phase of the telescope, called AMANDA-BIO, demonstrate both reliable operation and the broad astrophysical reach of this device, which includes searches for a variety of sources of ultrahigh energy neutrinos: generic point sources, Gamma-Ray Bursts and diffuse sources. The predicted sensitivity and angular resolution of the telescope were confirmed by studies of atmospheric muon and neutrino backgrounds. We also report on the status of the analysis from AMANDA-II, a larger version with far greater capabilities. At this stage of analysis, details of the ice properties and other systematic uncertainties of the AMANDA-II telescope are under study, but we have made progress toward critical science objectives. In particular, we present the first preliminary flux limits from AMANDA-II on the search for continuous emission from astrophysical point sources, and report on the search for correlated neutrino emission from Gamma Ray Bursts detected by BATSE before decommissioning in May 2000. During the next two years, we expect to exploit the full potential of AMANDA-II with the installation of a new data acquisition system that records full waveforms from the in-ice optical sensors.
The Furongian (late Cambrian) is an extremely poorly sampled time in the history of echinoderms, with only few localities yielding complete specimens. Here, we document an exquisitely preserved stemmed echinoderm from the Furongian Sandu Formation in South China that provides important new data illuminating the origin of Glyptocystitida, a common Palaeozoic clade of echinoderms. Sanducystis sinensis n. gen. n. sp. displays an organized theca bearing three circlets of plates (basal, infralateral and lateral), a laterally positioned periproct in the CD interray, a lack of respiratory pectinirhombs and a stem divided in two parts, with expanded inner and outer columnals proximally and narrow, elongate, homeomorphic columnals distally. A phylogenetic analysis places Sanducystis more derived than the columnal-bearing ‘eocrinoid’ Ridersia and sister group of a clade encompassing Macrocystella-like glyptocystitoid rhombiferans from the Furongian onwards. By filling in an important morphological gap, Sanducystis provides a clear understanding of character evolution within Glyptocystitida.
We show that Ribet sections are the only obstruction to the validity of the relative Manin–Mumford conjecture for one-dimensional families of semi-abelian surfaces. Applications include special cases of the Zilber–Pink conjecture for curves in a mixed Shimura variety of dimension 4, as well as the study of polynomial Pell equations with non-separable discriminants.
Breed risk status assessment methods are key components of country-based early warning and response systems. In this study, a multi-indicator method was developed to assess the risk status of livestock populations. Six indicators were used: (i) the current number of breeding females; (ii) the change in the number of breeding females over the last 5 years or generations (depending on the species); (iii) percentage of cross-breeding; (iv) effective population size; (v) breeders organization and technical support; and (vi) socio-economic context. To make these indicators comparable, observed values were converted into scores on a six-point scale (from 0 = no threat to 5 = maximum threat); a specific conversion method was used for each indicator. For each breed, the different scores were analysed graphically and an overall score was calculated by averaging the six separate indicator scores. This approach was applied to 178 French local breeds, belonging to ten different species: horse, donkey, goat, pig, chicken, turkey, goose and Pekin duck. A large percentage of local breeds were found to be at risk to be lost for farming, although the results were species dependent. All local equine and pig breeds, as well as almost all local poultry breeds appeared to be endangered. About 80 percent of local goat and cattle breeds, and half local sheep breeds were also found to be at risk. The usefulness of this method with regards to conservation strategies and public policy is discussed.
Stars in low-mass dwarf galaxies show a larger range in their chemical properties than those in the Milky Way halo. The slower star formation efficiency make dwarf galaxies ideal systems for testing nucleosynthetic yields. Not only are alpha-poor stars found at lower metallicities, and a higher fraction of carbon-enhanced stars, but we are also finding stars in dwarf galaxies that appear to be iron-rich. These are compared with yields from a variety of supernova predictions.
The study of the evolution of organic matter subjected to space conditions, and more specifically to Solar photons in the vacuum ultraviolet range (120–200 nm) has been undertaken in low-Earth orbit since the 1990s, and implemented on various space platforms. This paper describes a photochemistry experiment called AMINO, conducted during 22 months between 2009 and 2011 on the EXPOSE-R ESA facility, outside the International Space Station. Samples with relevance to astrobiology (connected to comets, carbonaceous meteorites and micrometeorites, the atmosphere of Titan and RNA world hypothesis) have been selected and exposed to space environment. They have been analysed after return to the Earth. This paper is not discussing the results of the experiment, but rather gives a general overview of the project, the details of the hardware used, its configuration and recent developments to enable long-duration exposure of gaseous samples in tight closed cells enabling for the first time to derive quantitative results from gaseous phase samples exposed in space.
Interventional cardiologists (ICs) are repeatedly exposed to scattered ionising radiation
during the cardiac procedures they perform, and radiation protection is an important issue
for these medical professionals. The use of radiation protection tools is particularly
relevant to this population. SISERI (Système d’Information de la Surveillance de
l’Exposition aux Rayonnement Ionisants, that is, an information system for monitoring
exposure to ionising radiation) is a register that stores personal dosimeter readings for
dosimetric monitoring. This paper, based on data for a sample of French ICs from the
O’CLOC epidemiological study, aims to provide an overview of the use of radiation
protection equipment and dosimetric devices reported by ICs in a specific questionnaire as
well as the dosimetric information found in the SISERI database for this population.
Material and Methods − Annual information on interventional cardiology activity for the
period from 01/01/2005 to 31/12/2009 was collected in an occupational questionnaire. ICs
were asked to report the frequency in which they used individual dosimeter and radiation
protection tools (lead apron, thyroid shield, eyewear or face shield, ceiling-suspended
shield) as follows: never (0% of the time), occasionally (<50%), regularly (>50%), always (100%). We retrieved their
medical radiation exposure information (monitored status and monthly effective doses) from
the SISERI database for the period 2005−2009. Results – Information for 132 ICs (mean age in
2005 = 46 ± 7 years) was
available. All ICs reported routine use of lead aprons, in contrast to their occasional
use of lead eyewear or face shields. During the study period, 49% reported systematic use
of personal dosimeters, and 21% more regular use. On the other hand, 18% never used a
dosimeter during this period. The SISTERI database included 92% of our population, 73% of
whom had complete annual dose monitoring in SISERI (corresponding to at least 11 months
per year of recorded data). Conclusion − ICs must improve their regular use of
radiation protection tools and systematic use of personal dosimeters. The SISERI database
is an appropriate tool for flagging those medical professionals exposed to ionising
radiation. Better awareness of the importance of radiation protection rules in this
population, in particular, systematic dosimeter use, remains an important issue.
The nature of the intermetallic layer which forms on the steel surface during immersion
in typical galvanizing baths for galvannealed (GA) sheets production has been investigated
on two commercial Titanium-stabilized Interstitial-Free (Ti-IF) steel substrates
galvanized in baths with different Al contents. Results from this study show that in both
cases the inhibition layer is biphasic and composed of a very thin Al-rich phase layer,
identified as Fe2Al5Znx, and a thicker Zn-rich phase layer
on top of it, identified as δ. Experimental results also show that the
Fe2Al5Znx phase layer becomes discontinuous
when decreasing the bath Al content. Discussions about the mechanisms of formation and the
final microstructure of this inhibiting layer are also tackled in this paper by means of
the Al-Fe-Zn ternary phase diagram at 460 °C and assumptions to justify any deviation from
thermodynamic equilibrium are as well proposed.
Epidemiological and other evidence suggests that vitamin D may be protective against several chronic diseases. Assessing vitamin D status in epidemiological studies, however, is challenging given finite resources and limitations of commonly used approaches. Using multivariable linear regression, we derived predicted 25-hydroxyvitamin D (25(OH)D) scores based on known determinants of circulating 25(OH)D, including age, race, UV-B radiation flux at residence, dietary and supplementary vitamin D intakes, BMI, physical activity, alcohol intake, post-menopausal hormone use (women only) and season of blood draw, in three nationwide cohorts: the Nurses' Health Study, Nurses' Health Study II and the Health Professionals Follow-up Study. The model r2 for each cohort ranged from 0·25 to 0·33. We validated the prediction models in independent samples of participants from these studies. Mean measured 25(OH)D levels rose with increasing decile of predicted 25(OH)D score, such that the differences in mean measured 25(OH)D between the extreme deciles of predicted 25(OH)D were in the range 8·7–12·3 ng/ml. Substituting predicted 25(OH)D scores for measured 25(OH)D in a previously published case–control analysis of colorectal cancer yielded similar effect estimates with OR of approximately 0·8 for a 10 ng/ml difference in either plasma or predicted 25(OH)D. We conclude that these data provide reasonable evidence that a predicted 25(OH)D score is an acceptable marker for ranking individuals by long-term vitamin D status and may be particularly useful in research settings where biomarkers are not available for the majority of a study population.
Background: The disaster response environment in Haiti following the 2010 earthquake represented a complex healthcare challenge. This study was designed to identify challenges during the Haiti disaster response.
Methods: Qualitative and quantitative study of injured patients carried out six months after the January 2010 earthquake in Haiti to review the surgical inputs of foreign medical teams.
Results: Study findings revealed a need during the response for improved medical records and data gathering for regulation, quality assurance, coordination and resource allocation; wider adherence to standard patient referral mechanisms and protocols linking surgical service provision with appropriate hospital and community based rehabilitation services; a greater recognition of the impact of non-amputation injury, and the need for patients to have a greater say in their management and to be the keepers of their medical records. Key first steps to improving the international response are a minimum dataset and uniform reporting.
Conclusion: This study showed that challenges for emergency medical response during the Haiti Earthquake involved issues of accountability, professional ethics, standards-of-care, unmet needs, patient agency and expected outcomes for patients in such settings:
To evaluate the clinical course and pathological characteristics of basaloid head and neck squamous cell carcinoma.
Retrospective study of 18 cases of basaloid head and neck squamous cell carcinoma. Epidemiological, clinical and histological data were analysed and the Kaplan–Meier test used to estimate survival rates.
The majority of lesions were at an advanced stage. These lesions were primarily localised in the larynx, hypopharynx and oropharynx. Routine pre-therapeutic assessment of squamous cell carcinoma was performed. Pathological diagnosis was difficult, although immunostaining was extremely useful. Positive staining for KL1, MNF 116 and 34βE12 and negative immunostaining for chromogranin and synaptophysin were also important factors in obtaining a definitive diagnosis. In the majority of cases, treatment involved surgery and radiotherapy. The five-year survival rate was 5 per cent.
Basaloid squamous cell carcinoma is an uncommon head and neck lesion, with a challenging histological diagnosis. These lesions must be carefully monitored due to their aggressive course, and require multimodality treatment.
A process to fabricate stretchable and adherent gold tracks on flat silicone rubber substrates is studied by X-ray photoelectron spectroscopy (XPS), static water contact angle measurement, atomic force microscopy (AFM) and scanning electron microscopy (SEM). The process involves several steps: curing flat silicone substrate; removing uncured oligomers by hexane Soxhlet extraction; pre-stretching the substrate; activating the strained silicone surface by an oxygen plasma treatment; coating the strained substrate with 5nm titanium and 80nm gold layers by e-beam evaporation; and finally releasing the sample. The plasma treatment creates a thin brittle silica-like layer that temporarily increases the substrate's surface energy. Indeed the plasma treatment is followed by a hydrophobic recovery. As a consequence, the delay between plasma treatment and metal deposition has to be reduced as much as possible. The silica-like layer can be nicely observed after release. Its thickness is estimated to be around 20nm to 50nm. The entire process allows us to obtain stretchable metallized samples that remain conductive even after an excessive deformation leading to electrical failure.
Plotting defect locations in insulating SiC presents a challenge because the total number of locations on a wafer is so large. We scan the wafer with visible light at an appropriate resolution and sort out transmissions appropriate for the defects we are looking for. Under these conditions, we find that voids and micropipes reduce the pixel transmission to 0.3 to 0.5. Sorting for this transmission reduces the number of pixels of interest to a manageable number, especially with recent progress in growing lower defect SiC. Now a commercial plotting program can easily display defect locations within a circle representing the wafer boundary. We verify the defect locations by scanning electron microscope secondary electron images and scanning optical microscope visible-light images at several resolutions.
The wetting property of polymers is very important in different applications such as biomaterials, textiles, aerospace (fluid management and materials processing in microgravity), and thin film adhesion. Therefore, there is a strong interest in the development of a new technology for the modification at will of this property. The use of low energy ion beams allows the modification of the first surface atomic layers. Nitrogen ions of 500 eV/at. were used to bombard the surface of polycarbonate (PC) samples to a fluence of 5×1016 at/cm2. Five different environments (oxygen, nitrogen, argon, dry air and vacuum) were used to store the samples for some hours (1 to 24 hours) after the implantation. Aging studies of the contact angle (advancing and receding) have shown that the environment gas influences the long term value of the contact angle and helps to maintain the stability of the treated surfaces with the passage of time. XPS and ToF-SIMS have been used to study the chemical effects of both N2+ ion irradiation and storage gas surrounding the samples. The results show faster aging in the case of the samples stored in vacuum, a harmful effect of nitrogen gas on the treatment and the formation of new chemical species for all treatments.
The practical adhesion of equine pericardium membranes bonded with surgical glue has been measured by the bulge-and-blister technique under injection of pressurized distilled water. The value of the interfacial crack propagation energy can be estimated from the critical debonding pressure. The measured practical adhesion energies are weak with regards to those of engineering structural adhesives, but they are reliable enough to allow a comparison between different surgical glues and a study of the influence of the bonding experimental conditions.
We propose a theoretical study for charging the floating gate composed of Si nanocrystals (NCs), in a non-volatile flash memory. Only a few electrons tunnel from the channel of a metal-oxide-semiconductor transistor into the two-dimensional array of nanocrystals.
Our model is based on the geometrical and physical properties of the device, in order to take the dispersion of the relevant parameters into account: NC radii, inter-NC distances, tunnel oxide and gate oxide thicknesses. The energy subbands of the channel are explicitly included, together with the doping density.
This three-dimensional model of electron tunneling into a NC is numerically solved through a two-dimensional finite element approach, which allows extensive numerical experimentations.
The tunneling times to charge a single NC or the whole NC floating gate are evaluated in a finer detail, and the influence of the dispersion of the relevant parameters is discussed.
Such a study may help the experimentalists to build efficient quantum flash memories.
Pseudomonas aeruginosa is one of the leading nosocomial pathogens. The question of the respective contribution of endogenous and exogenous sources remains controversial. In this study, we shed new light on this issue by means of a multilevel logistic regression analysis which allowed a simultaneous investigation of factors associated with prevalence of patients infected with P. aeruginosa at two levels: patient and healthcare facility (HCF) in the eastern regions of France. A total of 25 533 in-patients from 51 HCFs were included in the analysis. The overall prevalence was 0·37% (range 0–1·65%). Multilevel modelling estimated that <14% of total variability of the outcome variable was explained by differences between HCFs and that after adjusting for patient-level variables, which explained 52% of HCF-level variance, the latter became non-significantly different from zero. A compositional effect (patient factors), rather than a contextual effect (ecological factors), explains heterogeneity of the prevalence of patients infected with P. aeruginosa in the eastern HCFs of France.