Simulations and symmetries

We investigate the range of applicability of a model for the real-space power spectrum based on N-body dynamics and a (quadratic) Lagrangian bias expansion. This combination uses the highly accurate particle displacements that can be efficiently achieved by modern N-body methods with a symmetries-based bias expansion which describes the clustering of any tracer on large scales.We showthat at lowredshifts, and formoderately biased tracers, the substitution of N-body-determined dynamics improves over an equivalent model using perturbation theory by more than a factor of two in scale, while at high redshifts and for highly biased tracers the gains are more modest. This hybrid approach lends itself well to emulation. By removing the need to identify haloes and subhaloes, and by not requiring any galaxy-formation-related parameters to be included, the emulation task is significantly simplified at the cost ofmodelling a more limited range in scale. 2020 The Author(s)

提高全民對食品營養及安全的認知是解決食品安全問題的關鍵

本文結合最近發生的食品安全事件及嬰幼兒食品的營養及安全問題,指出食品安全問題在我國大有日趨嚴重之勢,并建議國家有關部門、媒體和社會各界共同配合,對廣大消費者和食品生產者進行食品營養和食品安全知識和法規的教育及宣傳,以提高他們的認知水平,這是解決食品安全問題的關鍵。 The recent food safety incidents and the infant food nutrition and safety issues indicate that food safety has become worse and worse in China.The article suggests that the key to solving the food safety problems fundamentally is to educate the consumers and food manufacturers,with the concerted efforts of government,media and the public,in order to enhance their understanding of food nutrition and safety

Identifying smart design attributes for Industry 4.0 customization using a clustering Genetic Algorithm

Industry 4.0 aims at achieving mass customization at a mass production cost. A key component to realizing this is accurate prediction of customer needs and wants, which is however a challenging issue due to the lack of smart analytics tools. This paper investigates this issue in depth and then develops a predictive analytic framework for integrating cloud computing, big data analysis, business informatics, communication technologies, and digital industrial production systems. Computational intelligence in the form of a cluster k-means approach is used to manage relevant big data for feeding potential customer needs and wants to smart designs for targeted productivity and customized mass production. The identification of patterns from big data is achieved with cluster k-means and with the selection of optimal attributes using genetic algorithms. A car customization case study shows how it may be applied and where to assign new clusters with growing knowledge of customer needs and wants. This approach offer a number of features suitable to smart design in realizing Industry 4.0

The foxconn suicides and their media prominence: is the werther effect applicable in china?

<p>Abstract</p> <p>Background</p> <p>Media reporting of suicide and its relationship with actual suicide has rarely been investigated in Mainland China. The "Foxconn suicides" is a description referring to a string of suicides/attempts during 2010, all of which were related to a giant electrical manufacturing company, Foxconn. This study aimed to examine the clustering and copycat effects of the Foxconn suicides, and to investigate temporal patterns in how they were reported by the media in Mainland China, Hong Kong (HK), and Taiwan (TW).</p> <p>Methods</p> <p>Relevant articles were collected from representative newspapers published in three big cities in Mainland China (Beijing (BJ), Shenzhen (SZ), and Guangzhou (GZ)), HK, and TW, together with searching intensity data on the topic conducted using the Baidu search engine in Mainland China. The temporal clustering effects of the Foxconn suicides and their media prominence were assessed using the Kolmogorov-Smirnov test. The media reports of the Foxconn suicides' temporal patterns were explored using a nonparametric curve estimation method (that is, the local linear method). The potential mutual interactions between the Foxconn suicides and their media prominence were also examined, using logistic and Poisson regression methods.</p> <p>Results</p> <p>The results support a temporal clustering effect for the Foxconn suicides. The BJ-based newspapers' reporting and the occurrence of a Foxconn suicide/attempt are each found to be associated with an elevated chance of a further Foxconn suicide 3 days later. The occurrence of a Foxconn suicide also immediately influenced the intensity of both Baidu searching and newspaper reporting. Regional diversity in suicide reporting tempo-patterns within Mainland China, and similarities between HK and TW, are also demonstrated.</p> <p>Conclusions</p> <p>The Foxconn suicides were temporally clustered. Their occurrences were influenced by the reporting of BJ-based newspapers, and contagion within the company itself. Further suicide research and prevention work in China should consider its special media environment.</p

On the identification of categories and choices for specification-based test case generation

HKU CS Tech Report TR 2004-02The category-partition method and the classification-tree method help construct test cases from specifications. In both methods, an early step is to identify a set of categories (or classifications) and choices (or classes). This is often performed in an ad hoc manner due to the absence of systematic techniques. In this paper, we report and discuss three empirical studies to investigate the common mistakes made by software testers in such an ad hoc approach. The empirical studies serve three purposes: (a) to make the knowledge of common mistakes known to other testers so that they can avoid repeating the same mistakes, (b) to facilitate researchers and practitioners develop systematic identification techniques, and (c) to provide a means of measuring the effectiveness of newly developed identification techniques. Based on the results of our studies, we also formulate a checklist to help testers detect such mistakes. © 2004 Elsevier B.V. All rights reserved.postprin

Trimaximal neutrino mixing from vacuum alignment in A4 and S4 models

Recent T2K results indicate a sizeable reactor angle theta_13 which would rule out exact tri-bimaximal lepton mixing. We study the vacuum alignment of the Altarelli-Feruglio A4 family symmetry model including additional flavons in the 1' and 1" representations and show that it leads to trimaximal mixing in which the second column of the lepton mixing matrix consists of the column vector (1,1,1)^T/sqrt{3}, with a potentially large reactor angle. In order to limit the reactor angle and control the higher order corrections, we propose a renormalisable S4 model in which the 1' and 1" flavons of A4 are unified into a doublet of S4 which is spontaneously broken to A4 by a flavon which enters the neutrino sector at higher order. We study the vacuum alignment in the S4 model and show that it predicts accurate trimaximal mixing with approximate tri-bimaximal mixing, leading to a new mixing sum rule testable in future neutrino experiments. Both A4 and S4 models preserve form dominance and hence predict zero leptogenesis, up to renormalisation group corrections.Comment: 24 pages, 2 figures, version to be published in JHE

Structural analysis of small-scale 3D printed composite tidal turbine blades

\ua9 2024 The AuthorsThe existing research literature lacks comprehensive investigations into assessing the structural performance of marine renewable energy conversion devices, particularly 3D printed turbine blades, which often rely solely on computational modelling without experimental validation methods and/or established mechanical characterization techniques. This leads to significant uncertainty regarding the performance of 3D printed turbine blades manufactured by additive manufacturing technology. This study aims to fill this gap by proposing a procedure for evaluating the structural integrity of commercial small-scale tidal turbine blade (5 KW) manufactured using fused filament fabrication 3D printing with a linear infill pattern. This is achieved by developing a combined experimental, hydrodynamic, and finite element approach with the view to inspect the micro-mechanical properties of representative volume elements of 3D printed microstructures using homogenization technique. The results of mechanical testing and hydrodynamic modelling are used to create a finite element model of the 3D printed blade, allowing for stress and failure analysis. Findings indicate that while integrating 3D printed materials into blade design via 3D printing technology is feasible, the choice of materials is limited to high stiffness composite filaments. Finally, experimental validation of numerical results, particularly full field strain distribution maps obtained by digital image correlation technique for flexural testing and laboratory-scale 3D printed blade, confirms the accuracy of the finite element results. Finite element-based homogenization techniques provide valuable insights into potential failure modes in 3D printed tidal turbine blades. However, the expedited calculation of orthotropic properties through finite element analysis proves to be a faster mechanical characterization method compared to experimental approaches. The proposed methodology in this study facilitates quicker iterative design of 3D printed blades, thereby reducing the need for repeated experiments and ultimately lowering manufacturing costs

Dynamic reciprocal relationships between traditional media reports, social media postings, and youth suicide in Taiwan between 2012 and 2021

Rising social media use over the past decade has been linked with increasing suicide rates among young people. Previous studies that assessed the impact of social media on suicide have typically focused on single social media platforms, such as Twitter, and assumed unidirectional associations, where social media posts leads to suicide. Our study focused on the past decade (2012–2021) which has witnessed a rapid increase of social media platforms and use. Poisson and negative binominal auto-regression models were employed to examine the dynamic reciprocity between social media, traditional media and youth suicides in Taiwan. Increased volume in suicide-related social media posts positively correlated with increased youth suicide rates (β = 2.53 × 10-5, 95% CI= (0.83 × 10-5, 4.24 × 10-5), P < 0.01), but increased rates of youth suicide was not related to an increase in suicide-related social media posts. Suicide-related posts on social media triggered reporting of suicide-related news on traditional media platforms (β = 3.35 × 10-2, 95% CI= (2.51 × 10-2, 4.19 × 10-2), P < 0.001), whilst traditional media reports of suicide led to increased suicide-related social media posts (β = 6.13 × 10-1, 95% CI = (4.58 × 10-1, 7.68 × 10-1); P < 0.001). However, suicide-related reports on traditional media platforms did not directly lead to an increase in youth suicide rates. Our findings highlight challenges for suicide prevention strategies in the 21st Century, in dealing with the increasing prominence of social media over traditional media. As social media is more difficult to regulate than traditional media, suicide prevention efforts must adapt to this new landscape by developing innovative strategies that address the unique risks and opportunities presented by social media

Immunomodulatory activity of Pestalotiopsis sp., an endophytic fungus from Tripterygium wilfordii

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Impact of melamine-tainted milk on foetal kidneys and disease development later in life

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