Inbuilt Mechanisms for Overcoming Functional Problems Inherent in Hepatic Microlobular Structure

This paper is funded by an MRC/EPSRC Discipline Bridging Initiative Grant (G0502256-77947) to W. Wan

The Ammann-Beenker tilings revisited

This paper introduces two tiles whose tilings form a one-parameter family of tilings which can all be seen as digitization of two-dimensional planes in the four-dimensional Euclidean space. This family contains the Ammann-Beenker tilings as the solution of a simple optimization problem.Comment: 7 pages, 4 figure

Ab initio prediction of the mechanical properties of alloys: The case of Ni/Mn-doped ferromagnetic Fe

First-principles alloy theory, formulated within the exact muffin-tin orbitals method in combination with the coherent-potential approximation, is used to study the mechanical properties of ferromagnetic body-centered cubic (bcc) Fe$_{1-x}$M$_x$ alloys (M=Mn or Ni, $0\le x \le 0.1$). We consider several physical parameters accessible from \emph{ab initio} calculations and their combinations in various phenomenological models to compare the effect of Mn and Ni on the properties of Fe. Alloying is found to slightly alter the lattice parameters and produce noticeable influence on elastic moduli. Both Mn and Ni decrease the surface energy and the unstable stacking fault energy associated with the $\{110\}$ surface facet and the $\{110\}\langle111\rangle$ slip system, respectively. Nickel is found to produce larger effect on the planar fault energies than Mn. The semi-empirical ductility criteria by Rice and Pugh consistently predict that Ni enhances the ductility of Fe but give contradictory results in the case of Mn doping. The origin of the discrepancy between the two criteria is discussed and an alternative measure of the ductile-brittle behavior based on the theoretical cleavage strength and single-crystal shear modulus $G\{110\}\langle111\rangle$ is proposed.Comment: 14 pages, 11 figure

Taxonomic revision of lizards from the Paleocene deposits of the Qianshan Basin, Anhui, China

Although the Late Cretaceous lizard fauna of China and Mongolia is relatively well-known, information on Paleocene lizards from the same region is currently limited. Several species of lizards have been reported from the Paleocene Wanghudun and Doumu formations of Qianshan Basin on the basis of fragmentary specimens, namely Agama sinensis Hou, 1974, Anhuisaurus huainanensis Hou, 1974, Anqingosaurus brevicephalus Hou, 1976, Changjiangosaurus huananensis Hou, 1976, Qianshanosaurus huangpuensis Hou, 1974, and Tinosaurus doumuensis Hou, 1974. In this paper, we review all the reported material of these taxa with the aid of new technology, including CT scanning, and according to current views of squamate relationships and classification. Revised descriptions and classifications are given for each taxon, leading to changes in our understanding of faunal composition. This, in turn, reveals greater morphological and ecological diversity among the Paleocene lizards of the Qianshan Basin, including the occurrence of a varaniform (IVPP V 22767), and the reinterpretation of Anqingosaurus as a possible burrower. Further work on the Paleocene Qianshan lizards is ongoing and the discovery of new specimens may help to solve the puzzles these strange lizards have posed

An Improved Time Feedforward Connections Recurrent Neural Networks

Recurrent Neural Networks (RNNs) have been widely applied to deal with temporal problems, such as flood forecasting and financial data processing. On the one hand, traditional RNNs models amplify the gradient issue due to the strict time serial dependency, making it difficult to realize a long-term memory function. On the other hand, RNNs cells are highly complex, which will significantly increase computational complexity and cause waste of computational resources during model training. In this paper, an improved Time Feedforward Connections Recurrent Neural Networks (TFC-RNNs) model was first proposed to address the gradient issue. A parallel branch was introduced for the hidden state at time t-2 to be directly transferred to time t without the nonlinear transformation at time t-1. This is effective in improving the long-term dependence of RNNs. Then, a novel cell structure named Single Gate Recurrent Unit (SGRU) was presented. This cell structure can reduce the number of parameters for RNNs cell, consequently reducing the computational complexity. Next, applying SGRU to TFC-RNNs as a new TFC-SGRU model solves the above two difficulties. Finally, the performance of our proposed TFC-SGRU was verified through several experiments in terms of long-term memory and anti-interference capabilities. Experimental results demonstrated that our proposed TFC-SGRU model can capture helpful information with time step 1500 and effectively filter out the noise. The TFC-SGRU model accuracy is better than the LSTM and GRU models regarding language processing ability

A reflection on recent efforts in optimization of cooling capacity of electrocaloric thin films

Despite the advantages of electric field efficiency and miniaturization, the limited operating temperature range and mediocre cooling efficiency of electrocaloric thin films represent the key obstacles to their practical applications in cooling advanced electronics. In this review, we discussed the current efforts and challenges facing the development of high-performance electrocaloric thin films and explored universal approaches along with their physical mechanisms for optimizing the electrocaloric response in thin films. We first emphasize the significance of the indirect method for determining the electrocaloric effect (ECE) in thin films and restate the conditions for the application of Maxwell’s equations. Particularly, we flag a couple of common artifacts of the electrocaloric results induced by the indirect method in recent attempts at the optimization of the ECE. We then cover chemical modification, interface engineering, and strain engineering as effective routes to improve the adiabatic temperature change (ΔT), reduce the driving electric field (E), and widen the operating temperature range (Tspan). At last, we propose that slush relaxors can be exploited as the base system for simultaneously achieving large ΔT, broad Tspan, and low E. Furthermore, we also discuss that the employment of high-entropy oxide perovskites is a feasible approach for greatly raising the dipolar entropy change under low electric fields. At last, we stress the significance and pressing need to measure the EC parameters of thin films with reliable direct methods. We hope that the high-performance electrocaloric thin films and the design rationale discussed in this review could inspire more facile and novel methods to achieve a better electrocaloric response

The free maternal health policy: acceptability and satisfaction with quality of maternal health services during pregnancy in rural Northern Ghana

Introduction: Ghana introduced a maternal health policy in July 2008 to provide free of cost health services to women. However, the utilization of services does not depend on affordability alone but acceptability as well. Acceptability includes attitudes and behaviors of providers and satisfaction with the quality of care. The study explored women’s views and perceptions about attitudes and behaviors of providers and satisfaction with the quality of services under the free maternal health policy in Ghana. In addition, the views and perceptions of providers were examined. Methods: A convergent parallel mixed-methods study was conducted. The study was carried out in the Kassena-Nankana Municipality in Ghana. A structured questionnaire was distributed among women (n=406) who utilized health facilities during pregnancy. Further, focus group discussions (FGDs) with women (n=10) and in-depth interviews with midwives and nurses (n=25) were held. Quantitative data were analyzed using descriptive statistics, while the qualitative data were recorded, transcribed, read, and coded thematically. Results: Women perceived facilities to be clean, especially the smaller ones. Ninety-eight percent of women (n=313/320) perceived providers to be respectful or friendly, and this was mostly confirmed in the FGDs. More than two-thirds of the women (74%, n=300) were also very satisfied or satisfied with the quality of care due to the respect accorded them by providers. Equally, midwives and nurses were satisfied with the quality of care they provided. Nonetheless, providers believed that the unavailability of drugs and supplies, laboratory services, accommodation, and transportation for emergencies reduced women’s satisfaction with services and the quality of care they could provide. Conclusion: The services provided to women during pregnancy were acceptable under the free maternal health policy. There remain challenges in addressing a lack of infrastructure and commodities that affects the quality of care

An improved version of white matter method for correction of non-uniform intensity in MR images: application to the quantification of rates of brain atrophy in Alzheimer's disease and normal aging

A fully automated 3D version of the so-called white matter method for correcting intensity non-uniformity in MR T1-weighted neuro images is presented. The algorithm is an extension of the original work published previously. The major part of the extension was the development of a fully automated method for the generation of the reference points. In the design of this method, a number of measures were introduced to minimize the effects of possible inclusion of non-white matter voxels in the selection process. The correction process has been made iterative. PI drawback of this approach is an increased cost in computational time. The algorithm has been tested on T1-weighted MR images acquired from a longitudinal study involving elderly subjects and people with probable Alzheimer's disease. More quantitative measures were used for the evaluation of the algorithm's performance. Highly satisfactory correction results have been obtained for images with extensive intensity non-uniformity either present in raw data or added artificially. With intensity correction, improved accuracy in the measurement of the rate of brain atrophy in Alzheimer's patients as well as in elderly people due to normal aging has been achieved

A new Jurassic lizard from China

The Jurassic record of lizards in eastern Asia is poor by comparison with that of the Cretaceous. In China, to date, the only confirmed records from this period are an armoured lizard from Shishugou, Xinjiang Uygur Autonomous Region, of probable Oxfordian age, and two unnamed juvenile specimens from the slightly older, Callovian-Oxfordian, Daohugou locality of Nei Mongol. Here we describe the first lizard from the locality of Guancaishan, Jianping County, Liaoning Province. This locality is close to Daohugou, and is considered t o be of similar age. The new skeleton is articulated and well-preserved. It is distinguished from other Jurassic-Cretaceous lizards by a unique combination of derived characters, notably a long frontal with posterior processes that clasp the short parietal; cranial osteoderms limited to the lower temporal and supraocular regions; and an elongated manus and pes. Phylogenetic analysis using morphological data alone places the new taxon on the stem of a traditional ‘Scleroglossa’, but when the same data is run with a backbone constraint tree based on molecular data, the new taxon is placed on the stem of Squamata as a whole. Thus its position, and that of other Jurassic and Early Cretaceous taxa, seem to be influenced primarily by the position of Gekkota