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.
This article provides an overview of selected ongoing international efforts that have been inspired by Edward Zigler's vision to improve programs and policies for young children and families in the United States. The efforts presented are in close alignment with three strategies articulated by Edward Zigler: (a) conduct research that will inform policy advocacy; (b) design, implement, and revise quality early childhood development (ECD) programs; and (c) invest in building the next generation of scholars and advocates in child development. The intergenerational legacy left by Edward Zigler has had an impact on young children not only in the United States, but also across the globe. More needs to be done. We need to work together with a full commitment to ensure the optimal development of each child.
This paper focuses on the problem of skin corrosion on the upper wing surfaces of rib-stiffened aircraft. For maritime and military transport aircraft this often results in multiple co-located repairs. The common approach to corrosion damage in operational aircraft is to blend out the corrosion and rivet a mechanical doubler over the region. In particular this paper describes the results of a combined numerical and experimental investigation into the ability of the additive metal technology, Supersonic Particle Deposition (SPD), to restore the load-carrying capacity of rib-stiffened wing planks with simulated skin corrosion. The experimental results reveal that unrepaired skin corrosion can result in failure by yielding. The experimental results also reveal that SPD repairs to skin corrosion can restore the stress field in the structure, and can ensure that the load-carrying capability of the repaired structure is above proof load.
In 2008, the Defense Advanced Research Project Agency commissioned a database known as the Integrated Crisis Early Warning System to serve as the foundation for models capable of detecting and predicting increases in political conflict worldwide. Such models, by signalling expected increases in political conflict, would help inform and prepare policymakers to react accordingly to conflict proliferation both domestically and internationally. Using data from the Integrated Crisis Early Warning System, we construct and test a self-exciting point process, or Hawkes process, model to describe and predict amounts of domestic, political conflict; we focus on Colombia and Venezuela as examples for this model. By comparing the accuracy of fitted models to the observed data, we find that we are able to closely describe occurrences of conflict in each country. Thus, using this model can allow policymakers to anticipate relative increases in the amount of domestic political conflict following major events.
The Vibrio cholerae O1 (VCO1) El Tor biotype appeared during the seventh cholera pandemic starting in 1961, and new variants of this biotype have been identified since the early 1990s. This pandemic has affected Vietnam, and a large outbreak was reported in southern Vietnam in 2010. Pulsed-field gel electrophoresis (PFGE) and multilocus variable-number tandem-repeat analyses (MLVA) were used to screen 34 VCO1 isolates from the southern Vietnam 2010 outbreak (23 patients, five contact persons, and six environmental isolates) to determine if it was genetically distinct from 18 isolates from outbreaks in southern Vietnam from 1999 to 2004, and two isolates from northern Vietnam (2008). Twenty-seven MLVA types and seven PFGE patterns were identified. Both analyses showed that the 2008 and 2010 isolates were distinctly clustered and separated from the 1999–2004 isolates.
Chronic rhinosinusitis is characterised by persistent inflammation of the sinonasal mucosa. Multiple pathophysiological mechanisms are likely to exist. Previous research has focused predominantly on T-helper type cytokines to highlight the inflammatory mechanisms. However, proteins such as nuclear factor kappa B and transforming growth factor beta are increasingly recognised to have important roles in sinonasal inflammation and tissue remodelling.
This review article explores the roles of T-helper type cytokines, nuclear factor kappa B and transforming growth factor beta in the pathophysiological mechanisms of chronic rhinosinusitis. An understanding of these mechanisms will allow for better identification and classification of chronic rhinosinusitis endotypes, and, ultimately, improved therapeutic strategies.
Anxiety disorders are associated with abnormalities in amygdala function and prefrontal cortex–amygdala connectivity. The majority of functional magnetic resonance imaging studies have examined mean group differences in amygdala activation or connectivity in children and adolescents with anxiety disorders relative to controls, but emerging evidence suggests that abnormalities in amygdala function are dependent on the timing of the task and may vary across the course of a scanning session. The goal of the present study was to extend our knowledge of the dynamics of amygdala dysfunction by examining whether changes in amygdala activation and connectivity over scanning differ in pediatric anxiety disorder patients relative to typically developing controls during an emotion processing task. Examining changes in activation over time allows for a comparison of how brain function differs during initial exposure to novel stimuli versus more prolonged exposure. Participants included 34 anxiety disorder patients and 19 controls 7 to 19 years old. Participants performed an emotional face-matching task during functional magnetic resonance imaging scanning, and the task was divided into thirds in order to examine change in activation over time. Results demonstrated that patients exhibited an abnormal pattern of amygdala activation characterized by an initially heightened amygdala response relative to controls at the beginning of scanning, followed by significant decreases in activation over time. In addition, controls evidenced greater context-modulated prefrontal cortex–amygdala connectivity during the beginning of scanning relative to patients. These results indicate that differences in emotion processing between the groups vary from initial exposure to novel stimuli relative to more prolonged exposure. Implications are discussed regarding how this pattern of neural activation may relate to altered early-occurring or anticipatory emotion-regulation strategies and maladaptive later-occurring strategies in children and adolescents with anxiety disorders.
The banteng Bos javanicus is a globally threatened species of wild cattle restricted to South-East Asia. We report the first robust estimate of banteng density and population size from anywhere in the species' global range, using distance-based line transect sampling within two protected areas, Mondulkiri Protected Forest and Phnom Prich Wildlife Sanctuary, which form part of the Eastern Plains Landscape, Cambodia. We surveyed 110 line transects multiple times during the dry seasons of 2009–2010 and 2010–2011. In a total survey effort of 1,310 km there were 63 encounters with banteng. The mean estimate of the population across the 3,406 km2 study area is 3,200 (95% confidence interval 1,980–5,170). This suggests that the protected area complex of the Eastern Plains Landscape supports the majority of the global population of banteng. Stronger protection, both in the form of increased anti-hunting and poaching patrols and integrated land-use planning to prevent habitat loss within protected areas, is essential for securing wild cattle populations in the Eastern Plains Landscape.
Non-typhoidal Salmonella are an important but poorly characterized cause of paediatric diarrhoea in developing countries. We conducted a hospital-based case-control study in children aged <5 years in Ho Chi Minh City to define the epidemiology and examine risk factors associated with Salmonella diarrhoeal infections. From 1419 diarrhoea cases and 571 controls enrolled between 2009 and 2010, 77 (5·4%) diarrhoea cases were stool culture-positive for non-typhoidal Salmonella. Salmonella patients were more likely to be younger than controls (median age 10 and 12 months, respectively) [odds ratio (OR) 0·97; 95% confidence interval (CI) 0·94–0·99], to report a recent diarrhoeal contact (8·1% cases, 1·8% controls; OR 5·98, 95% CI 1·8–20·4) and to live in a household with >2 children (cases 20·8%, controls 10·2%; OR 2·32, 95% CI 1·2–4·7). Our findings indicate that Salmonella are an important cause of paediatric gastroenteritis in this setting and we suggest that transmission may occur through direct human contact in the home.
In Vietnam, highly pathogenic avian influenza (HPAI) H5N1 infections in poultry often occur without concomitant clinical signs and outbreaks are not consistently reported. Live bird markets represent a convenient site for surveillance that does not rely on farmers' notifications. Two H5N1 surveys were conducted at live bird markets/slaughter points in 39 districts (five provinces) in the Red River, Mekong delta, and central Vietnam during January and May 2011. Oropharyngeal and rectal swab samples from 12 480 ducks were tested for H5N1 by reverse transcription–polymerase chain reaction in pools of five. Traders and stallholders were interviewed using standardized questionnaires; 3·3% of pools tested positive. The highest prevalence (6·6%) corresponded to the Mekong delta, and no H5N1 was detected in the two Red River provinces. The surveys identified key risk behaviours of traders and stallholders. It is recommended that market surveys are implemented over time as a tool to evaluate progress in HPAI control in Vietnam.
Multiple salmonellosis outbreaks have been linked to contaminated tomatoes. We investigated a multistate outbreak of Salmonella Typhimurium infections among 190 cases. For hypothesis generation, review of patients' food histories from four restaurant-associated clusters in four states revealed that large tomatoes were the only common food consumed by patients. Two case-control studies were conducted to identify food exposures associated with infections. In a study conducted in nine states illness was significantly associated with eating raw, large, round tomatoes in a restaurant [matched odds ratio (mOR) 3·1, 95% confidence interval (CI) 1·3–7·3]. In a Minnesota study, illness was associated with tomatoes eaten at a restaurant (OR 6·3, mid-P 95% CI 1·05–50·4, P=0·046). State, local and federal regulatory officials traced the source of tomatoes to Ohio tomato fields, a growing area not previously identified in past tomato-associated outbreaks. Because tomatoes are commonly eaten raw, prevention of tomato contamination should include interventions on the farm, during packing, and at restaurants.
We have successfully prepared La0.5Sr0.5MnO3nanowires using a novel hydrothermal synthesis process and studied their magnetic and magnetocaloric properties. The system exhibits an inverse magnetocaloric effect (IMCE) around 175 K indicating presence of significant AFM correlation. The MCE study reveals a clear paramagnetic (PM) to ferromagnetic (FM) transition near room temperature (T ~ 325K) which is followed by onset of AFM at lower temperatures. The development of the FM-like magnetic state at low temperature is attributed to the enhanced double exchange (DE) driven ferromagnetism in AFM state as predicted by recent theoretical studies.
The current status of the DRIFT (Directional Recoil Identification From Tracks)
experiment at Boulby Mine is presented, including the latest limits on the WIMP
spin-dependent cross-section from 1.5 kg days of running with a mixture of CS2
and CF4. Planned upgrades to DRIFT IId are detailed, along with ongoing work
towards DRIFT III, which aims to be the world’s first 10 m3-scale directional
Dark Matter detector.
Pt/Pb(Zr0.4Ti0.6)O3 (PZT)/Pt capacitors were prepared by the sol-gel technique and their electric properties were analyzed. The asymmetry of polarization-electric field (P-E) and capacitor-voltage (C-V) curves exhibits existence of an interface layer (dead-layer) between top Pt electrode and PZT thin film. By conducting temperature dependant measurement, the Pt/PZT/Pt capacitor was confirmed to be Schottky emission conduction. In addition, barrier height of PZT contact calculated 0.67eV. On basic a series capacitors model and Schottky contact of Pt/PZT interface, the thickness and the dielectric constant of this dead-layer were estimated to be 6.4 nm and 170, respectively. Moreover, the dielectric constant of 900 was obtained for the real PZT ferroelectric layer. The existence of the dead-layer was also confirmed by the high resolution transmission electron microscopy (HR-TEM) observation and the energy dispersive X-ray (EDX) analysis on PZT ferroelectric layer in the Pt/PZT/Pt structure. Based on EDX analysis result, a 10-nm layer at Pt/PZT contact was suggested to be the dead-layer.
We report on the use of La2O3 (LO) as a capping layer for ferroelectric-gate thin-film transistors (FGTs) with solution-processed indium-tin-oxide (ITO) channel and Pb(Zr,Ti)O3 (PZT) gate insulator. The fabricated FGT exhibited excellent performance with a high “ON/OFF” current ratio (ION/IOFF) and a large memory window (∆Vth) of about 108 and 3.5 V, respectively. Additionally, a significantly improved data retention time (more than 16 hours) as compared to the ITO/PZT structure was also obtained as a result of good interface properties between the ITO channel and LO/PZT stacked gate insulator. We suggest that the LO capping layer acts as a barrier to prevent the interdiffusion and provides atomically flat ITO/LO/PZT interface. This all-oxide FGT device is very promising for future ferroelectric memories.
Un nouvel outil a été développé pour optimiser l’efficacité des traitements par le DTPA après blessure, sur la base d’une réduction de la dose efficace engagée. Les simulations montrent, notamment, que pour du 239Pu modérément soluble (type M), des traitements précoces (24 i.v.) étalées sur 4 mois permettent une réduction d’un tiers de la dose, alors que leur prolongement sur 5 ans, avec un intervalle de 2 semaines, peut diminuer la dose d’un facteur 5. En revanche, pour des composés peu solubles (type S), l’efficacité des traitements précoces est négligeable et un gain dosimétrique d’un facteur 3 n’est atteint que pour des traitements effectués 2 fois par mois durant 50 ans. Certaines des hypothèses retenues pour la modélisation ont été validées par les résultats d’expérimentations animales récemment publiés. Enfin, la structure d’un nouveau modèle applicable à la fois au Pu et à l’Am est rapportée, structure tenant compte de la décorporation urinaire et fécale de ces actinides et qui pourrait être adapté à différentes posologies et formes galéniques de DTPA.
The Very Large Telescope (VLT) Observatory on Cerro Paranal (2635
m) in Northern Chile is approaching completion. After the four 8-m
Unit Telescopes (UT) individually saw first light in the last years,
two of them were combined for the first time on October 30, 2001 to
form a stellar interferometer, the VLT Interferometer. The remaining
two UTs will be integrated into the interferometric array later this
year, so that any two UTs can be used for interferometry. In this
article, we will describe the subsystems of the VLTI and the planning
for the following years.
Bioactive materials such as calcium phosphate ceramics and bioactive glasses enhance bone tissue formation and then bond to bone tissue. In our work, we question what particular surface feature or features of bioactive materials are responsible for the bone tissue response. In this study we have uncoupled surface charge from surface chemistry, energy, and topography and have examined osteoblast adhesion to titanium surfaces of varying surface charge. We have shown that a negative surface charge promotes osteoblast adhesion by approximately 60% over a neutral surface and that conversely, a positive surface charge inhibits osteoblast adhesion by about 20%. Continued examination of surface characteristics that control cellular responses are warranted with the eventual goal of applying those desirable surface characteristics to any structural biomaterial for bone implant or tissue engineering applications.
The boundary-element method is used to solve Stokes equations for periodic arrays of force-free and torque-free rigid particles. Simple cubic arrays of spheres, spheroids, cubes, and clusters of spheres are subjected to a bulk simple shearing flow. The effective volume-averaged stress tensor for the suspension and the detailed velocity and stress fields throughout the Newtonian suspending fluid are calculated. We find that even crude meshes give very good volume-averaged results, but fine meshes are required to track local minima and maxima in the stress field. For simple cubic arrays of spheres, the boundary-element results are in excellent agreement with the analytical viscosity predictions of Nunan & Keller (1984). Even at the highest concentration of solids studied, no significant normal stress differences were observed, in agreement with Nunan & Keller's results (1984). Up to moderate concentrations of particles, the volume-averaged properties of the suspension display only a weak dependence on the particle geometry. Suspensions of spheroids and cubes behave approximately as suspensions of spheres on the average despite large differences in the local micromechanics of stress and velocity fields. Simple cubic arrays of clusters of spheres tend to behave on a macroscopic level as a cubic array of spheres whose effective volume fraction is about 150% of the total volume fraction of the spheres in the clusters.
A computational technique for obtaining minimum-time trajectories for robot manipulators is described in this paper. In the analysis, limitations to link movements due to design constraints are taken into consideration. Numerical examples based on a two-link planar robot arm shows the feasibility of the technique proposed. A physical explanation for the general characteristics of the observed trajectories is also presented. The importance of appreciating optimal control issues in designing robot manipulators and in planning robot workstation layouts is emphasised.