Food Safety Management System validation and verification in meat industry: Carcass sampling methods for microbiological hygiene criteria – A review

During validation and verification of the system for the proper implementation of HACCP principles, it is essential to rely on microbiological data. Considerable science research has been carried out during the last twenty years on sampling and testing of carcasses for hygiene criteria. This includes the preferable indicator microorganisms to be used, in order to indicate the general hygiene of slaughtering procedures, the evaluation of microbiological data gathered and the sampling methods. Furthermore, European Union (EU) and the United States have adopted the procedures for HACCP validation and verification in their legislation. The aim of this review is to demonstrate the relevant modern trends in this field of food science. In conclusion, microbiological data based on the indicators should be interpreted only to assess general trends in the hygiene process of the operator in order to take corrective action. Microbiological results, obtained only at the end of the slaughtering process, do not provide information on the cause of the problem. Therefore, ‘process-based’ microbiological criteria which are based on values measured at various stages of the process, including final carcass values, should be used. Finally, in order to implement an adequate monitoring system, non-destructive techniques of carcass sampling could be used instead of excision. The microbial recovery may be lower, but it is proportional to the excision recovery and therefore, non-destructive techniques, like swabbing with sponges, could be a practical sampling method for the estimation of indicators during the slaughtering procedure and hygiene evaluation.     

非饱和土大气张力通用公式与库仑土压力

推出大气张力库仑土压力的近似计算方法：假设临界破裂角为已知,可以考虑多层粘性土、坡面任意荷载、水和气压力。提出粘性土的结合水膜可靠连接面积率修正系数等于粘粒含量。推出大气张力库仑抗剪强度公式的Cm 形式,Cm 是膜的抗剪强度贡献。     

Discontinuities in the evolution of the city system in Texas from 1850 to 2010

We report the results of a historical investigation and quantification of discontinuous evolution, and a gap statistic analysis of discontinuities, on city size distributions of the city system in Texas, USA, over a 160-year period from 1850 to 2010. The growth of the city system exhibits four stages that are evident from our quantitative analysis of the convergence of population in large cities and qualitative analysis of historical socioeconomic and technological developments. The decadal city size distributions in the aggregate evolve with a persistent pattern while individual cities over time shift positions in the urban hierarchy as the result of adapting or passing growth opportunities in infrastructure innovations, economic change, and industrial transformations. These decadal city size distributions exhibit persistent discontinuities that mainly occur in the upper and lower tails. The observed patterns and discontinuities are indicative of the stability and resilience of a complex adaptive system of cities.     

Estimating cost of equity in project discount rates using the capital asset pricing model and Gordon’s wealth growth model

Since the 2008 global financial crisis, mining projects have to invariably compete for scarce capital under depressed market conditions. The discounted cash flow analysis commonly used for the valuation of mining projects relies on using a discount rate. However, an appropriate discount rate is sometimes the subject of contestation since factors such as the stage of development of the mineral project affect the rate. This paper independently tests the reliability of capital asset pricing model and Gordon’s wealth growth model estimates of cost of equity in discount rates and concludes that Gordon’s wealth growth model provides better estimates under depressed market conditions.     

Comment on “Further improvement on delay-range-dependent robust absolute stability for Lur׳e uncertain systems with interval time-varying delays” by P. Liu [ISA Trans. 58(2015)58–66]

In a recent paper (ISA Transactions (2015)58: 58–66), an integral inequality has been proposed to reduce the conservativeness of stability conditions for Lur׳e uncertain systems. We point out that there exist some errors in Theorems 1–8, and the correct theorems are presented. Finally, the allowable maximum admissible upper bound (MAUB) listed in Table 1, Table 2, Table 3, Table 4, Table 5 have been recalculated by using the correct results.     

富铁面包酵母的筛选及富集条件研究

本文探索获得富铁面包酵母的富集条件。筛选获得一株富铁能力较强的面包酵母菌株QN006。通过单因素实验确定该菌株富铁工艺条件为:铁盐种类为硫酸亚铁,亚铁离子浓度为900μg/mL,添加时间为0h,温度为28℃,pH为5.0。在此条件测得面包酵母QN006的铁富集量为13.92mg/g干菌体,不加糖面团发酵力达到623mL/h。     

2种二芳醚农药中间体的合成

[目的]二芳醚是重要的农药中间体,用于合成多种重要的杀虫剂,如一些拟除虫菊酯、杀菌剂如醚唑等农药。3,4’-二氯二苯醚和3-甲基二苯醚分别是醚唑和戊菊酯的关键中间体,传统上采用铜粉为催化剂合成效率和选择性欠佳,为此,对2种二芳醚中间体合成进行优化和改进。[方法]采用商用铜粉和自制高分散铜为催化剂,分别对溶剂、反应摩尔比、反应温度、反应时间进行优化合成2种二芳醚中间体。[结果]3,4’-二氯二苯醚的选择性达86.7%,收率为82.2%;3-甲基二苯醚的收率为96.8%。[结论]实验结果显示高分散铜的催化活性和选择性都好于传统Ullmann反应催化剂。     

Cooperation in the evolutionary iterated prisoner’s dilemma game with risk attitude adaptation

The Iterated Prisoner’s Dilemma (IPD) game has been commonly used to investigate the cooperation among competitors. However, most previous studies on the IPD focused solely on maximizing players’ average payoffs without considering their risk preferences. By introducing the concept of income stream risk into the IPD game, this paper presents a novel evolutionary IPD model with agents seeking to balance between average payoffs and risks with respect to their own risk attitudes. We build a new IPD model of multiple agents, in which agents interact with one another in the pair-wise IPD game while adapting their risk attitudes according to their received payoffs. Agents become more risk averse after their payoffs exceed their aspirations, or become more risk seeking after their payoffs fall short of their aspirations. The aspiration levels of agents are determined based on their historical self-payoff information or the payoff information of the agent population. Simulations are conducted to investigate the emergence of cooperation under these two comparison methods. Results indicate that agents can sustain a highly cooperative equilibrium when they consider only their own historical payoffs as aspirations (called historical comparison) in adjusting their risk attitudes. This holds true even for the IPD with a short game encounter, for which cooperation was previously demonstrated difficult. However, when agents evaluate their payoffs in comparison with the population average payoff (called social comparison), those agents with payoffs below the population average tend to be dissatisfied with the game outcomes. This dissatisfaction will induce more risk-seeking behavior of agents in the IPD game, which will constitute a strong deterrent to the emergence of mutual cooperation in the population.     

Assessment of driver stopping prediction models before and after the onset of yellow using two driving simulator datasets

Accurate modeling of driver decisions in dilemma zones (DZ), where drivers are not sure whether to stop or go at the onset of yellow, can be used to increase safety at signalized intersections. This study utilized data obtained from two different driving simulator studies (VT-SCORES and NADS datasets) to investigate the possibility of developing accurate driver-decision prediction/classification models in DZ. Canonical discriminant analysis was used to construct the prediction models, and two timeframes were considered. The first timeframe used data collected during green immediately before the onset of yellow, and the second timeframe used data collected during the first three seconds after the onset of yellow. Signal protection algorithms could use the results of the prediction model during the first timeframe to decide the best time for ending the green signal, and could use the results of the prediction model during the first three seconds of yellow to extend the clearance interval. It was found that the discriminant model using data collected during the first three seconds of yellow was the most accurate, at 99% accuracy. It was also found that data collection should focus on variables that are related to speed, acceleration, time, and distance to intersection, as opposed to secondary variables, such as pavement conditions, since secondary variables did not significantly change the accuracy of the prediction models. The results reveal a promising possibility for incorporating the developed models in traffic-signal controllers to improve DZ-protection strategies.     

Combined heat and power economic dispatch using integrated civilized swarm optimization and Powell’s pattern search method

An integrated technique that embeds civilized swarm optimization (CSO) and Powell’s pattern search (PPS) method is proposed to search economic dispatch of combined heat and power (CHP) dispatch problem. In the proposed technique, CSO is selected as global search technique and PPS is undertaken as a local search technique. Civilized swarm optimization is having attributes of particle swarm optimization (PSO) and society civilization algorithm (SCA). In CSO, mutually interacting societies forms the civilization. The positions of society particles are updated through the guidance of own leader along with their best positions. The best performing particle of CSO is further improved by PPS method based on a certain set criterion. The PPS method is based on the conjugate search direction method and does not require the gradient or Hessian matrix of the function to be optimized. The CHP dispatch problem has a mutual dependency of demand and heat-power capacity of generating units, so it requires an effective constraint handling strategy. In this work, variable reduction strategy with exterior penalty method is applied to satisfy equality constraints. The proposed technique is tested on five CHP test systems considering valve-point loading effect, prohibited operating zones constraint, and transmission losses. The obtained results are compared to the results reported in the literature and found satisfactory. Further, for verification of statistical performance of the proposed technique, t-test and Wilcoxon signed rank test is also performed.