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.
The willow sawfly, Nematus oligospilus (Förster), is a pest in Salix commercial forests and has been reported worldwide. Female adults must recognize a suitable host plant to oviposit, since her offspring lack the ability to move to another host. We evaluated the effect of conspecific herbivory on the oviposition choices of N. oligospilus females by providing damaged (DP) and undamaged (UP) plants of Salix humboldtiana, a native willow from South America, as oviposition substrates. Local and systemic effects were studied. For the local treatment, a twig from the DP with damaged leaves was contrasted to a twig from a UP in dual choice experiments. For systemic treatment, a twig from the DP with intact leaves was contrasted to a twig from a UP. We estimated the use of olfactory and contact cues by comparing volatile emission of DP and UP, and by analysing the behaviour of the females during host recognition after landing on the leaf surface. In the context of the preference–performance hypothesis (PPH), we also tested if oviposition site selection maximizes offspring fitness by evaluating neonate hatching, larval performance and survival of larvae that were born and bred on either DP or UP. Our results demonstrate that previous conspecific herbivory on S. humboldtiana has a dramatic impact on female oviposition choices and offspring performance of the sawfly N. oligospilus. Females showed a marked preference for laying eggs on UP of S. humboldtiana. This preference was found for both local and systemic treatments. Volatile emission was quantitatively changed after conspecific damage suggesting that it could be related to N. oligospilus avoidance. In the dual choice preference experiments, the analysis of the behaviour of the females once landing on the leaf surface suggested the use of contact cues triggering egg laying on leaves from UP and avoidance of leaves from DP. Furthermore, 48 h of previous conspecific feeding was sufficient to dramatically impair neonate hatching, as well as larval development and survival, suggesting a rapid and effective reaction of the induced resistance mechanisms of the tree. In agreement with the PPH, these results support the idea that decisions made by colonizing females may result in optimal outcomes for their offspring in a barely studied insect model, and also opens the opportunity for studying tree-induced defences in the unexplored South American willow S. humboldtiana.
OBJECTIVES/SPECIFIC AIMS: By combining clinical knowledge of hoarding disorder (HD) with qualitative methods from cultural anthropology, we hope to build a patient-centered approach that will allow us to better understand the clinician perspectives on patient motivations and explanatory models of individuals with HD, and improve treatment outcomes. We describe the ways that these methodologies are productively merged in this project as a result of TL1 collaboration, and present a preliminary picture of methodological and theoretical issues uncovered as part of this processes. We further describe the analytical methods used for this project, and explore issues raised through the combination of psychological and anthropological data and insights. METHODS/STUDY POPULATION: This study represents an attempt to combine the qualitative methodologies of cultural anthropology with the clinical knowledge of psychology and psychiatry in order to better understand gaps between provider and patient beliefs and knowledge about hoarding disorder. This study will present preliminary methodological issues arising from interviews with hoarding experts. RESULTS/ANTICIPATED RESULTS: This study will discuss preliminary issues including shared language, strengths and limitations of both disciplines, and factors for consideration when combining these disparate methodologies. It will close with recommendations for consideration when moving forward with similar collaborations. DISCUSSION/SIGNIFICANCE OF IMPACT: This project seeks to unite psychological and social factors that may contribute to the lived experience of individuals with HD in order to better understand the way that HD is manifested. It also unites disparate methodologies to provide us with a more holistic and complete picture of the experience of HD. While HD has been studied within psychiatry, it has never been assessed using the qualitative methods of anthropology. These methods provide the possibility of expanding knowledge about the ways that this disorder is experienced by individuals and their families, and potentially impacted by shared beliefs and cultures. Furthermore, qualitative data of this nature provides a patient perspective on the experience of HD as a psychiatric illness. This patient perspective can be used to better inform treatment, improve patient outcomes, and to allow providers and researchers to gain a fuller understanding of this complex population.
This study was aimed to investigate associations between birth weight and multiple adiposity indicators in youth, and to examine potential mediating effects by biological maturation. This was a school-based study involving 981 Brazilian adolescents aged between 10 and 17 years. Birth weight was reported retrospectively by mothers. Maturation was estimated by age of peak height velocity. Adiposity indicators included body mass index (BMI), waist circumference and percent body fat estimated from triceps and subscapular skinfolds. Multilevel mediation analyses were performed using the Sobel test, adjusted for chronological age, gestational age, cardiorespiratory fitness and socio-economic status. Except for body fat in girls, biological maturation partly or fully mediated (P<0.05) positive relationships between birth weight with all other obesity indicators in both sexes with their respective values of indirect effects with 95% confidence intervals: BMI [boys: 0.44 (0.06–0.82); girls: 0.38 (0.13–0.64)], waist circumference [boys: 1.14 (0.22–2.05); girls: 0.87 (0.26–1.48)] and body fat [boys: 0.60 (0.13–1.07)]. To conclude, birth weight is associated with elevated obesity risk in adolescence and biological maturation seems to at least partly mediate this relationship.
Laboratory surface science under ultra-high vacuum (UHV) conditions allows us to simulate the growth of ices in astrophysical environments. Using the techniques of temperature programmed desorption (TPD), reflection-absorption infrared spectroscopy (RAIRS) and micro-balance methods, we have studied binary ice systems consisting of water (H2O) and variety of other species including carbon monoxide (CO), at astrophysically relevant conditions of temperature and pressure. We present results that demonstrate that the morphology of water ice has an important influence on the behavior of such systems, by allowing processes such as diffusion and trapping that can not be understood through a knowledge of the binding energies of the species alone. Through an understanding of the implications of water ice morphology on the behavior of ice mixtures in the interstellar environment, additional constraints can be placed on the thermodynamic conditions and ice compositions during comet formation.
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.
UGIB remains a common disease affecting 100 to 170 adults per year, with an associated mortality ranging from 5 to 14%, causing thereby an important burden to healthcare resources. UGIB in children is uncommon (1–2/10,000 per year) but potentially life threatening. Since various specialists (general practitioners, emergency physicians, gastroenterologists and hepatologists, pediatricians, intensivists, radiologists and surgeons) may be involved and given the absence of evidence-based medical (EBM) recommendations - for adults as well as for children - there is considerable variability in the management of UGIB. Moreover, as even RCTs on the management of UGIB in children are lacking, many treatment strategies are simply deducted from the management of adult UGIB.
To provide EBM guidelines for the care of adults and children presenting with bleeding caused by gastro-duodenal ulcer or variceal rupture.
Method and Results
An interuniversity interdisciplinary team of Belgian experts was launched. Statements based on the published literature up to September 2010 were collected and proposed after expert opinions reconciliation and graded accordingly to the class of evidence. The current guidelines for the management of UGIB include recommendations for the diagnosis process, general supportive care, pharmacological therapy aiming at bleeding control, specific and endoscopic treatment of acute bleeding and follow-up for both gastro-duodenal ulcers and portal hypertension induced bleeding. Specificities and differences in the approach to UGIB in children compared to adults are highlighted.
Interdisciplinary guidelines for the management of UGIB based on current standards for EBM will provide an opportunity for clinicians to improve the management of their patients. However, clinical guidelines are not mandatory tenets appropriate for all patients, but should constitute a canon or principle tailored to the individual patient. In addition, EBM might provide quality indicators for the assessment of care to bleeding patients at a local, national or international level.
Materials processing in a microgravity environment is aimed at developing commercial materials as well as investigating basic phenomena to improve earth-based processing. Materials research in space has dealt with glasses and ceramics, crystal growth, electronic materials, metals and alloys, polymers, composites, and biological materials. Battelle has been conducting research in this area since the early-1970s. Several important results have been obtained in: immiscible alloys, containerless under-cooling of clustering alloys, sol-gel glasses, and collagen fibers.
More recently, Battelle's Advanced Materials Center for the Commercial Development of Space (CCDS) has been established to utilize the microgravity environment in the commercial development of composite and mixed-phase materials with substantially improved properties. Currently, the Center is conducting research in catalysts (variant-phase chlorides, zeolites, and mixed oxides), polymer systems, electronic materials (float-zone crystal growth on Type II-VI semiconductor crystals, particularly CdTe), and con-trolled- porosity glass. The present program focuses on a proof of principle for each research thrust, utilizing ground-based and suborbital facilities, together with modeling to demonstrate the potential for producing commercially important materials.
Each of these research programs is outlined. In addition, the more important developments in each of the major categories of microgravity materials research is reviewed.
Hard, adherent, 2 μm thick lubricious silicon containing diamond-like carbon coatings (Si-DLC) were synthesized by 40 keV Ar+ ion beam assisted deposition (IBAD) of tetraphenyltetramethyl-trisiloxane oil on two, 5 cm by 5 cm by 0.64 cm thick 4340 steel substrates. Two different substrate surface finishes were examined, I polished and 1 600 grit finish (unpolished). The corrosion resistance of the Si-DLC coating was evaluated by Electrochemical Impedance Spectroscopy (EIS) in a 0.005N concentration sodium chloride (NaCI) solution. Low frequency impedance data from each of the coatings were compared with those of bare steel. The Si-DLC coating deposited on the polished substrate performed slightly better than the one deposited on the unpolished surface. Overall the Si-DLC coating did not appear to offer very much corrosion protection to the steel. This was mainly attributed to the presence of pinholes in the coating. Furthermore, to study the effect of radiation on the electronic structure of the Si-DLC coating, three Si-DLC coatings synthesized under the same deposition conditions on silicon substrates at various oil precursor temperatures were irradiated by a 355 nm wavelength, 0.37 Watts, pulsed YAG Laser at 35 kHz. Corrosion and irradiation results and procedures to minimize the pinhole density in the Si-DLC coating will be discussed in detail
Carbon silicon nitride (CSixNy), and carbon boron nitride (CBxNy) thin films have been grown by pulsed laser deposition (PLD) of various carbon (silicon/boron) (nitride) targets using an additional nitrogen RF plasma source on  oriented silicon substrates without additional heating. The CSixNy and CBxNy thin films were amorphous and showed nano hardness up to 23 GPa compared to 14 GPa for silicon and maximum nitrogen content of 30 at%. The maximum nanohardness was achieved for 10% Si and 10% B content in the films. The lower hardness of this films compared to the nanohardness of 30-50 GPa of DLC films indicates a lower amount of covalent carbon-nitrogen bonding in the films. However, in contrast to DLC films, the CSixNy and CBxNy films can be grown to thickness above 3 μm due to lower internal compressive stress. XPS of CSixNy and CBxNy film surfaces shows clear correlation of binding energy and intensity of N ls, C ls, and Si 2p peaks to composition of the PLD-targets and to nitrogen flow through plasma source, indicating soft changes of binding structure due to variation of PLD parameters. The results demonstrate the capability of the plasma assisted PLD process to deposit hard amorphous CSixNy, and CBxNy thin films with adjustable properties.
It is well established that the structural characteristics of graphite nanofibers can be controlled by several factors including, the chemical nature of the catalyst, the composition of the reactant gas mixture and temperature at which the growth process is performed. In the current investigation we have endeavored to modify the behavior of the catalyst by dispersing the active metals on different support media. We have found that the strength of the metal-support interaction exerts a significant impact not only on the average size of the nanofibers generated by such a procedure, but also results in major changes in the architecture of the carbon materials. The support imposes certain geometrical constraints on the metal particles and these features are manifested in modifications in the degree of crystalline perfection and arrangement of the graphite sheets constituting the nanofibers. In addition, there is also the possibility that the support can induce electronic perturbations in the metal particles, a feature that will be most pronounced with a conductive carrier.
Single wall nanotubes have been made by arc-discharge method. Residual impurities (fullerenes, amorphous carbon, catalyst metals…) have been removed by tangential filtration process followed by high temperature annealing under vacuum (1200 °C). In this work we present results on the influence of the surrounding gas nature (N2, H2, CO2, H2O…) on the electrical resistivity of carefully outgassed mat of such samples.
In particular, we have observed that the sample resistance exhibits a strong dependence on water contamination during the transfer to the measurement reactor.
In this contribution, we report on a mechanical method to cut and open single walled carbon nanotubes. This technique is based on using an abrasive material (diamond powder) without any chemical treatments or oxidation in air at high temperature. We present highresolution transmission electron microscopy micrographs, which show firstly that the tubes are unambiguously opened and secondly, that the nanotubes have not suffered the treatment. x-ray diffraction pattern confirms a well-defined bundle organisation. A breaking mechanism of the nanotube bundles is proposed. Nitrogen adsorption measurements at 77K reveal the presence of new microporosities ranging in the average nanotube diameter, which confirm the opening of some tubes.
Diamond-like carbon (DLC) films have been prepared by pulsed laser deposition (PLD) (wavelength 248 nm), ablating highly oriented pyrolytic graphite (HOPG) at room temperature in a vacuum of 10−2Pa, at fluences between 0.5 and 35 Jcm−2. Films have been deposited on Si(100) with and without a SiC interlayer. Structural analysis, such as visible and UV Raman, Infrared and Electron Energy Loss (EEL) spectroscopies show that the films are hydrogen-free and undergo a transition, from mainly disordered graphitic to up to 80% tetrahedral amorphous carbon (ta-C), above a laser threshold fluence of 5 J cm−2. The measured residual stresses of as deposited ta-C films do not exceed 2 GPa. Scratch tests show excellent adhesion properties. Low friction coefficients (0.05-0.1) have been measured in ambient humidity. Nanoindentation indicates that film hardness is as high as 70 GPa
Nanostructured carbon films have been grown by deposition of supersonic cluster beams. A novel pulsed microplasma cluster source allows to obtain cluster beams of high intensity and stability. Cluster growth and beam formation have been charaterized. Separation effects typical of supersonic expansions cause inhomogeneities of cluster distribution in the beam, depending on their masses. This effect, observed for the first time, has been carefully characterized. The deposited films have a low density porous structure based on nanometer-size grains. The coordination is essentially three-fold with a large number of defects. Film density, morphology and surface roughness can be controlled by varying the precursor cluster mass distribution. Applications of cluster-assembled carbon films will be presented.
The phonon density of states of single-wall carbon nanotubes (SWNT) was measured by inelastic neutron scattering (INS) in a large energy range (0 to 120 meV). New information on the vibrational dynamics of SWNT is reported and compared with calculated density-of-sates. At lower frequencies (< 12 meV) we observe a peculiar energy dependence which we attribute to contributions from inter-tube modes in the 2D lattice of SWNT bundles, and also from effects of intertube coupling on the intra-tube excitations.
A variety of carbon nanotube films have been fabricated and tested as cold cathodes. A spray deposition technique was developed for processing as-grown bulk nanotubes, both single-walled and multi-walled, into films of randomly oriented nanotubes. Films of randomly oriented multi-walled nanotubes were grown using thermal chemical vapor deposition, and arrays of well-aligned multi-walled nanotubes have been fabricated using a microwave plasma enhanced chemical vapor deposition technique. The emission current-voltage (I-V) characteristics of these nanotube cathodes have been measured. Both multi-walled (random and aligned) and single-walled carbon nanotubes exhibit low turn-on fields (∼ 2 V/μm to generate 1 nA) and threshold fields (< 5 V/μm to generate 10 mA/cm2). Significantly, these cathodes were capable of operation at very large current densities (> 1A/cm2), making them candidates for application in a variety of vacuum microelectronic devices.
Boron-alloy coatings can be formed by sputtering compound targets, through co-deposition with other elemental targets, by utilizing reactive gas mixtures, and/or by post-deposition implantation. Specific to this study, boron-alloy coatings are assessed with respect to composition as deposited by co-sputtering boron and beryllium. Transmission electron microscope (TEM), bright-field images with selected area diffraction are used to reveal the microstructure and phase. Refinement in grain size to the nanoscale occurs through boron addition as well as transition metal impurities. An increase in coating hardness with boron addition is measured using nanoindentation. Scanning electron microscope (SEM), secondary electron images reveal the surface morphology variations for thick coatings that occur with boron addition as measured using energy dispersive spectrometry (EDS). The phase formed in boron-alloyed beryllium coating is found to be dependent on both coating composition and the sputter deposition conditions. It is concluded that the geometry of the deposition sources with the configuration of the substrate effect the coating composition, microstructure, and properties
An individual single-walled carbon nanotube (SWNT) has been shown [1-4] to exhibit remarkable electronic properties which depend on its diameter and chirality. In this work, the 13C nuclear magnetic resonance technique is used to measure quantitatively the electronic density-of-state (DOS) at the Fermi level in a bulk SWNT sample. Two types of 13C nuclear spins are observed with drastically different nuclear spin-lattice relaxation time (Tl). About onethird of the 13C nuclear spins with shorter Tl, are identified to reside at the metallic SWNTs and two-thirds can be associated with the semiconducting SWNTs. For the metallic SWNTs, the DOS at the Feimi level is measured quantitatively, which is about 0.022 states/(eV·atom·spin). The measured electronic DOS at the Fermi level agrees with the theoretical prediction for metallic tubes. This study also found that the semiconducting SWNTs in bundles, in fact, possess weak metallic characters. This indicates that tube-tube interactions within SWNT bundles could change the electronic properties.