The Birth of the Biotechnology Era: Penicillin in Australia, 1943–80 1

Abstract

As Australia and other countries seek to establish biotechnology industries, it is timely to review successes and failures in this field. One of the most notable stories is the development of penicillin, as a wartime project, to which Australians made major contributions. Australians during and immediately after the war contributed much to the scientific identification and purification of penicillin, and to the industrial scaling up in its production at the Commonwealth Serum Laboratories in Melbourne. This was a classic instance of war accelerating innovations in public administration. Yet the nascent antibiotic industry was never allowed to gain international competitiveness, and was allowed to run down and eventually disappeared by the end of the 1970s. This article is concerned to tease out the puzzle posed by this contrast in aspirations, between the highest levels of scientific and technical achievement in bringing penicillin into widespread use (Australia being the first country in the world to provide penicillin to the civilian population in 1944) and shockingly poor performance in sustaining and developing a national antibiotics industry. As the stirrings of a biotechnology industry may be observed in the first decade of the twenty‐first century, it would be unfortunate to ignore the lessons of this earlier experience at the birth of the biotechnology era.     

人造神经网络(1943年)

沃伦·麦卡洛克(1898～1972年),瓦特·皮茨(1924～)与人脑不同,常规电脑只能机械地服从程序指令,无法触类旁通。而人造神经网络可以模仿人脑进行信息处理。在人脑中,信息通过"联会"在几十亿个神经细胞(神经元)之间传递。神经细胞分支众多,每个分支又联结着成千上万的神经元,因而神经网络错综复杂,具有强大的计算能力。     

细菌的基因(1943年)

萨尔瓦多·爱德华·卢里亚(1912～1991年),马克斯·德尔布鲁克(1906～1981年)细菌是无处不在的单细胞生物,它们无所不在。有些细菌对人体无害,有些则是致病菌。它们在     

Lagrange半三角及Newton三角多项式逼近

插值法是函数逼近论中一个重要的内容.用半三角函数的Lagrange插值以及Newton插值来逼近2π反周期函数的结果相对较少.本文证明了当插值节点为偶数个时,半三角Lagrange插值问题的适合定的.这与多项式Lagrange插值存在着本质区别.同时我们给出了半三角Lagrange插值问题以及Newton插值问题的提法并构造了插值基函数.     

数值分析中Newton迭代法证明数列极限存在

数值分析中Newton迭代法来证明递推数列极限的存在。     

Distributed reconstruction of time-varying graph signals via a modified Newton’s method

This paper develops a distributed reconstruction algorithm, that can be implemented efficiently, for time-varying graph signals. The reconstruction problem is formulated as an unconstrained optimization problem that minimizes the weighted sum of the data fidelity term and the regularization term. The regularizer used is the nonsmoothness measure of the temporal difference signal. The classical Newton’s method can be used to solve the optimization problem. However, computation of the Hessian matrix inverse is required, and this does not scale well with the graph size. Furthermore, a distributed implementation is not possible. An approximation to the inverse Hessian, that exploits the graph topology, is developed here. The resulting iterative algorithm can be implemented in a distributed manner, and scales well with the graph size. Convergence analysis of the algorithm is presented, which shows convergence to the global optimum. Numerical results, using both synthetic and real world datasets, will demonstrate the superiority of the proposed reconstruction algorithm over existing methods.     

Markov chain Monte Carlo based adaptive Rauch–Tung–Striebel smoother

For linear state space model, the covariance matrix setting errors of process and measurement noise deteriorate the estimation performance of Rauch–Tung–Striebel (RTS) smoother. To address this problem, the Markov Chain Monte Carlo is utilized to sample the state vector and noise covariance matrices simultaneously in this study. The Gibbs sampler is adopted and the corresponding adaptive RTS smoother is designed. Simulation results confirm the performance of proposed smoother.     

Integrated study of the water–ecosystem–economy in the Heihe River Basin

The ecological water diversion project in the Heihe River Basin is the irst successful case in China in which the ecological systems in a river basin have been rescued. his project serves as a valuable example for the management of ecosystems in other inland river basins. his paper reviews the integrated studies of the water–ecosystem–economy relationship in the Heihe River Basin and concludes that sustainable development in inland river basins requires the basin to be considered as a whole, with the relationships between the upstream, midstream and downstream areas of the basin coordinated appropriately. Successful development in these basins will be relected in an improved output per cubic meter of water and the implementation of integrated river basin management practices.     

Battle of Systems: Learning from Erstwhile Gas–Electricity and Telegraph–Telephone Battles

Abstract

This paper seeks to understand how the possibility of a complementary relationship or its lack impacts dynamics of competition between two competing network technologies. It examines the cases of gas–electricity and telegraph–telephone competition. The two case studies suggest that the degree of complementarity greatly shapes the dynamics of competition between an entrenched network technology and a new competitor. When there is little scope for a complementary relationship, as in the case of the gas–electricity battle, the strategists for the new technology have to subvert the old system and build a new one on its ashes since there is little chance of coexistence. On the other hand, the possibility of a complementary relationship, as in the case of the telegraph–telephone battle, allows for the emergence of complex situations marked by coexistence interwoven with competition. These compromise positions, invariably involving re‐negotiation of boundaries, are tempting resting spots for battle weary contestants. As the relationship between the old and the new system evolves, the nature of the complementary relationship changes, especially in the relative power of the two systems, and even if eventually the old system fades away the process is a long and gradual one.     

Boundary stabilization of a class of reaction–advection–diffusion systems via a gradient-based optimization approach

In this paper, the boundary stabilization problem of a class of unstable reaction–advection–diffusion (RAD) systems described by a scalar parabolic partial differential equation (PDE) is considered. Different the previous research, we present a new gradient-based optimization framework for designing the optimal feedback kernel for stabilizing the unstable PDE system. Our new method does not require solving non-standard Riccati-type or Klein–Gorden-type PDEs. Instead, the feedback kernel is parameterized as a second-order polynomial whose coefficients are decision variables to be tuned via gradient-based dynamic optimization, where the gradients of the system cost functional (which penalizes both kernel and output magnitude) with respect to the decision parameters are computed by solving a so-called “costate” PDE in standard form. Special constraints are imposed on the kernel coefficients to ensure that the optimized kernel yields closed-loop stability. Finally, three numerical examples are illustrated to verify the effectiveness of the proposed approach.