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.
Disarticulated net-like plates of the lobopod Microdictyon had a near cosmopolitan distribution from the early to middle Cambrian but are yet to be documented from the North China Platform. Here we report isolated plates of Microdictyon from the lower Cambrian Xinji Formation (Stage 4, Series 2) of the North China Platform, extending the paleogeographic distribution of Microdictyon in the early Cambrian. The plates of Microdictyon from the Xinji Formation are similar to those of other species established on the basis of isolated plates but do bear some new characters, such as mushroom-shaped nodes with a single inclined platform-like apex and an upper surface that displays radial lines. However, the plates documented here are left under open nomenclature due to inadequate knowledge of intraspecific and ontogenetic variation and low specimen numbers. Through comparison of the node shapes of the isolated plates of different Microdictyon species, we consider that low mushroom-shaped nodes could be a primitive and conservative character of Microdictyon while tall mushroom-shaped nodes may be a derived character. Subtle differences in shape and number of node apices may also represent intraspecific or ontogenetic variation.
Newer echocardiographic techniques may allow for more accurate assessment of right ventricular function. Adult studies have correlated these echocardiographic measurements with invasive data, but minimal data exist in the paediatric congenital heart population. The purpose of this study was to evaluate echocardiographic measurements that correlate best with right ventricular systolic and diastolic catheterisation parameters.
Patients with two-ventricle physiology who underwent simultaneous echocardiogram and cardiac catheterisation were included in this study. Right ventricular systolic echocardiographic data included fractional area change, displacement, tissue Doppler imaging s’ wave, global longitudinal strain, and strain rate s’ wave. Diastolic echocardiographic data included tricuspid E and A waves, tissue Doppler imaging e’ and a’ waves, and strain rate e’ and a’ waves. E/tissue Doppler imaging e’, tissue Doppler imaging e’/tissue Doppler imaging a’, E/strain rate e’, and strain rate e’/strain rate a’ ratios were also calculated. Catheterisation dP/dt was used as a marker for systolic function and right ventricular end-diastolic pressure for diastolic function.
A total of 32 patients were included in this study. The median age at catheterisation was 3.1 years (0.3–17.6 years). The DP/dt was 493±327 mmHg/second, and the right ventricular end-diastolic pressure was 7.7±2.4 mmHg. There were no significant correlations between catheterisation dP/dt and systolic echocardiographic parameters. Right ventricular end-diastolic pressure correlated significantly with strain rate e’ (r=−0.4, p=0.02), strain rate a’ (r=−0.5, p=0.03), and E/tissue Doppler imaging e’ (r=0.4, p=0.04).
Catheterisation dP/dt did not correlate with echocardiographic measurements of right ventricular systolic function. Strain rate and tissue Doppler imaging analysis significantly correlated with right ventricular end-diastolic pressure. These values should be further studied to determine whether they may be used as an alternative method to estimate right ventricular end-diastolic pressure in this patient population.
A new cyanolichen, Peltigera islandica sp. nov. in the section Peltigera (‘P. canina group’) is described from Iceland. This species is similar in general appearance to P. rufescens and P. membranacea, but may be recognized by its downturned lobe tips and narrow lobes, respectively. Most thalli are bright emerald green in colour when moist, although a dark khaki green colourmorph is also documented. Monophyly of P. islandica s. lat. (i.e. including P. sp. A sensu O’Brien et al., from Canada) is significantly supported based on ITS sequences and corroborated by molecular synapomorphy (absence of the ITS1 hypervariable region). Analysis of the rbcLX locus indicates the cyanobiont of P. islandica (Nostoc sp.) comprises strains belonging to a pool of Icelandic genotypes, some of which are present in other Peltigera species, including P. “neorufescens”, another taxon new to Iceland collected during this study. Association with photobionts that are shared by other local species suggests P. islandica may be well established in Iceland, but a review of herbarium collections as well as broader field surveys are needed to better characterize its geographical distribution.
An outbreak of acute hepatitis recently occurred in a nursing home in Zhejiang Province, China. The objectives of this study were to confirm the outbreak and identify the aetiology, source and transmission patterns. All residents and staff in or near the nursing home during the period from 1 October 2014 to 21 May 2015 were investigated regarding hygiene and for epidemiological information including water and food (eating meat especially pork products). Serum and stool specimens were collected for detection of hepatitis E virus (HEV) antibodies using ELISA and RNA using RT–PCR. Samples that were RNA positive were genotyped. Of 185 senior residents and 24 staff in the nursing home, there were 37 laboratory-confirmed cases during the outbreak. Of these cases, 12 patients (three deaths) were symptomatic with jaundice, a common clinical symptom for hepatitis E infection. HEV strains were isolated from three cases and they formed a single cluster within genotype 4d. A case-control study was conducted to investigate potential risk factors for the outbreak and the results revealed that cases more often washed their dishes and rinsed their mouths using tap water than the controls (P < 0·05). Based on hygiene investigation and meteorological information, it is likely that HEV-infected sewage and faeces contaminated the water network on rainy days. Collectively, these results suggest that the outbreak of HEV genotype 4 infection was most likely caused by contaminated tap water rather than food.
To reduce the amount of chalcogen needed in the post-annealing process, we demonstrate significantly increased sulfur incorporation into pure sulfide CZTS films achieved by increasing the thiourea content of DMSO-based precursor solution. The increase of sulfur content was confirmed by thermogravimetric analyses (TGA). To understand how the elemental distribution across the CZTS layer is affected by extra thiourea, a systematic compositional study was carried out using X-ray photoelectron spectroscopy (XPS). XPS depth profiling reveals increased sulfur incorporation in the final CZTS films when more thiourea is added to the solution. The grain size was reduced slightly with increased sulfur content and the surface morphology was changed significantly. The effect on the surface of the CZTS film has been investigated using scanning electron microscopy (SEM), Raman spectroscopy, and XPS. External-quantum-efficiency (EQE) measurements with an electrolyte contact were used to investigate the optoelectronic properties of the deposited CZTS films.
This report will try to review briefly the work achieved from 1982 to 1984 in different “subjects to be considered by Commission 31 Time” as adopted in Grenoble 1976. It contains also information provided by Commission members, for which hearty thanks are to be given. The limitation of space required the abbrevation of some institution reports.
The abundance and cross-linking of intramuscular connective tissue contributes to the background toughness of meat, and is thus undesirable. Connective tissue is mainly synthesized by intramuscular fibroblasts. Myocytes, adipocytes and fibroblasts are derived from a common pool of progenitor cells during the early embryonic development. It appears that multipotent mesenchymal stem cells first diverge into either myogenic or non-myogenic lineages; non-myogenic mesenchymal progenitors then develop into the stromal-vascular fraction of skeletal muscle wherein adipocytes, fibroblasts and derived mesenchymal progenitors reside. Because non-myogenic mesenchymal progenitors mainly undergo adipogenic or fibrogenic differentiation during muscle development, strengthening progenitor proliferation enhances the potential for both intramuscular adipogenesis and fibrogenesis, leading to the elevation of both marbling and connective tissue content in the resulting meat product. Furthermore, given the bipotent developmental potential of progenitor cells, enhancing their conversion to adipogenesis reduces fibrogenesis, which likely results in the overall improvement of marbling (more intramuscular adipocytes) and tenderness (less connective tissue) of meat. Fibrogenesis is mainly regulated by the transforming growth factor (TGF) β signaling pathway and its regulatory cascade. In addition, extracellular matrix, a part of the intramuscular connective tissue, provides a niche environment for regulating myogenic differentiation of satellite cells and muscle growth. Despite rapid progress, many questions remain in the role of extracellular matrix on muscle development, and factors determining the early differentiation of myogenic, adipogenic and fibrogenic cells, which warrant further studies.
Excellent sites are necessary for developing and installing ground-based large telescopes. For very-high-resolution solar observations, it had been unclear whether there exist good candidate sites in the west areas in China, including the Tibetan Plateau and the Pamirs Plateau. The project of solar site survey for the next-generation large solar telescopes, i.e., the Chinese Giant Solar Telescope (CGST) and the large coronagraph, has been launched since 2011. Based on the close collaboration among Chinese solar society and the scientists from NSO, HAO and other institutes, we have successfully developed the standard instruments for solar site survey and applied them to more than 50 different sites distributed in Xinjiang, Tibet, Qinghai, Sichuan, Yunnan and Ningxia provinces. We have built two long-term monitoring sites in Tibet and the large Shangri-La to take systematic site data. Clear evidence, including the key parameters of seeing factor, sky brightness and water vapor content, has indicated that a few potential sites in the large Tibetan areas should obtain the excellent astronomical conditions for our purpose to develop CGST and large coronagraph. We introduce the fresh site survey results in this report.
An introduction to gravitational wave astronomy and detectors
D. G. Blair, University of Western Australia,
L. Ju, University of Western Australia,
C. Zhao, University of Western Australia,
H. Miao, California Institute of Technology,
E. J. Howell, University of Western Australia,
P. Barriga, University of Western Australia
D. G. Blair, University of Western Australia, Perth,E. J. Howell, University of Western Australia, Perth,L. Ju, University of Western Australia, Perth,C. Zhao, University of Western Australia, Perth
This chapter first introduces gravitational wave detection from a very general point of view, before looking at the particular methods of detection across the spectrum from nanohertz to kilohertz. It finishes by focusing specifically on terrestrial laser interferometers.
The discovery of radio waves by Heinrich Hertz in 1886 unleashed the communications revolution which has transformed our lives. Optimisation of radio receivers required understanding and integration of two concepts. The first was the concept of the antenna, which taps energy from a wave freely propagating in space and converts it into a signal which can be amplified and detected. The second was the receiver, which processes this energy by detection (converting it to a slowly time-varying voltage), amplification (increasing its amplitude without changing its frequency) or modulation (changing its frequency).
Designing gravitational wave receivers is analogous to designing radio receivers, except that electric charges moving freely in conductors are replaced by test masses floating freely in space. This concept was illustrated in Figure 1.2 in Chapter 1, showing how a ring of test particles is deformed by a passing gravitational wave. The first gravitational wave receivers were constructed by Joseph Weber in the 1960s. They took the form of large test masses in which gravitational waves could induce quadrupole vibrations. Weber went on to develop the Weber bar, in which one searched for excitations in the fundamental longitudinal vibrational mode of a cylinder. In this case, the receiver can be idealised as a pair of point masses joined by a mechanical spring.
Our practical experiments highlight that aluminum-silicon (Al-Si) and gold-silicon (Au- Si) eutectics are fairly inert to the attack of both anisotropic and isotropic wet etchants of Si (e.g. KOH or HF/HNO3 solutions). Therefore, these interfacial eutectics can be used as etch-stop layers in wet etching-based bulk micromachining. This paper presents how Al-Si and Au-Si eutectic layers may be employed for applications whose production involves such operations (e.g. high-pressure sensors) and will discuss three major directions of interest: eutectic formation, diaphragm generation and application of the eutectic layer in a pressure sensor.
The magnetic interaction of magneto-optical multilayer films have been analyzed using the stress mechanism of coercivity and the single ion model of magnetic anisotropy. The relation between the magnetic properties of the multilayer films and the dielectric film thickness has been explained.
The growth temperature and properties of Ge4Sb3Te3 thin films are presented in this paper. The critical growth temperature of Ge4Sb3Te3 is between 300 and 340 °C. The Ge4Sb3Te3 films can only be grown on a substrate below the critical growth temperature. The typical resistivity and carrier density are in the order of 10-4 Ωcm and 1021 cm-3 for crystalline phase. It has a rock salt crystal structure with a lattice constant of 0.602 nm. Ge4Sb3Te3 has a better thermal stability but a lower crystallization speed than Ge2Sb2Te5.
Time resolved imaging has been used to investigate the whole process of the crystallization induced by intense 130 femtosecond laser pulses in as-deposited Ge1Sb2Te4 films. With an average fluence of 24mJ/cm2 a transient non-equilibrium state of the excited material is formed within 1 picosecond. The results are consistent with an electronically induced non-thermal phase transition.
Complex phase transformation between the hexagonal cylinder (Hex) and double gyroid (G) phases in a polystyrene-block-poly(ethylene oxide) (PS-b-PEO) diblock copolymer was investigated using two-dimensional (2D) synchrotron small-angle X-ray scattering (SAXS), and transmission electron microscope (TEM). The PS-b-PEO sample contained a small population of another bicontinuous cubic phase having an Im3m symmetry. These two bicontinuous cubic phases (G and Im3m) had the same unit cell dimensions. Under a large-amplitude reciprocating shear, the bicontinuous cubic phases transformed into a “single-crystal”-like Hex phase. When annealed at 150 °C for 40 min, the Hex phase partially transformed into well-oriented twinned structures of the G and Im3m phases without significant loss of orientation in 2D SAXS measurements. Epitaxial phase transformation relationships between the Hex/G and Hex/ Im3m phases were identified. The mechanism of the Hex → G transformation was examined by TEM.
This article presents current R&D activities at Observatoire de Paris – Laboratoire d'Etude du Rayonnement
et de la Matière en Astrophysique in the fields of low noise mixers and local oscillators for heterodyne instruments dedicated to astrophysics, planetology and the sciences of the atmosphere.
Based on the radial basis function (RBF) and the singular hybrid boundary node method (SHBNM), this paper presents an inherent meshless, boundary-only technique, which names dual reciprocity singular hybrid boundary node method (DRSHBNM), for numerical solution of various inhomogeneous equations. In this study, the RBFs are employed to approximate the inhomogeneous terms via dual reciprocity method (DRM), while the general solution is solved by means of SHBNM, in which only requires discrete nodes constructed on the boundary of a domain, while several nodes in the domain are needed for the RBF interpolation. The treatment of singularity integration and the 'boundary layer effect' have been given by a series of effective approaches. Numerical examples for the solution of inhomogeneous equations show that high convergence rates and high accuracy with a small node number are achievable.
A solid polythiophene pellet was ablated by a KrF excimer laser beam to deposit thin films on silicon substrates. The laser-ablated plasma was studied by optical emission spectroscopy to identify the photon-breaking of C–S bonds in the ablated heterocycles. Raman and x-ray photoelectron spectroscopy measurements of the deposited thin films also supported the selective photon-induced bond breaking. After eliminating sulfur in the molecular structures, the thin films appeared to be composed of cubic nanocrystals with a uniform size of 240 nm. X-ray diffraction measurement determined the cubic crystal structures with a lattice constant of α =3.38 Å and suggested a quasi-onedimensional carbon chain structure along the body diagonal of the cube.
Thin films of polythiophene, a kind of polyheterocyclic compound with hydrogen function groups, were deposited by KrF excimer laser ablation of a compressed solid target in a vacuum chamber. The laser pulse fluence was approximately selected at 2 J/cm2 with a pulse duration of 25 ns. The structural, topographic, and electronic properties of the deposited thin films were analyzed by atomic force microscope, x-ray diffraction, and Raman and infrared spectroscopy measurements. Deposited thin films were observed to have good crystal properties and to be composed of crystalline cubes with a uniform size of 0.1 μm. The electronic structure of the deposited thin films should be different from the target materials, resulting from the laser irradiation effects. The influence of the deposition temperature on the structural and electronic properties of the deposited thin films was studied.
In this paper we describe the preparation, microstructure, and x-ray excited luminescence of vapor-deposited CaWO4 films up to about 50 μm thick, comparing them to particulate CaWO4 phosphor screens, used in medical diagnostic imaging. Films that we e-beam evaporated on substrates heated at or above 500 °C were polycrystalline with the scheelite structure, while on unheated substrates, films were initially amorphous but became crystalline after annealing them in air above about 750 °C. Crystalline CaWO4 films irradiated with x-rays produced light emission peaked at 430 nm. The emission intensity depended on film thickness and grain size and was comparable to particulate CaWO4 phosphor screens. Because the vapor-deposited films also exhibited superior resolution, they are promising for diagnostic x-ray imaging.
Email your librarian or administrator to recommend adding this to your organisation's collection.