Electron-spin domains: magnetic enhancement of superconductivity

An inhomogeneous superconducting state, not yet conclusively identified, was predicted by Fulde and Ferrell and Larkin and Ovchinnikov (FFLO) to arise in superconductors with strong Pauli limiting, a consequence of the electrons' Zeeman (spin) energy in a magnetic field. Radovan et al. propose that the observed cascades of steps in magnetization of the heavy fermion superconductor CeCoIn5, within the recently discovered second low-temperature state, are due to transitions between Landau-level (LL) states with different m-quanta vortices, expected under certain conditions when the magnetic field is swept within the FFLO state. The authors then conclude that the observed steps in magnetization constitute a proof that the low-temperature state in CeCoIn5 is indeed an FFLO state. We argue that this interpretation of the observed steps in magnetization cannot be supported on either quantitative or qualitative grounds.     

Lifespan and mitochondrial control of neurodegeneration

We examine the allometric (comparative scaling) relationships between rates of neurodegeneration resulting from equivalent mutations in a diverse group of genes from five mammalian species with different maximum lifespan potentials. In both retina and brain, rates of neurodegeneration vary by as much as two orders of magnitude and are strongly correlated with maximum lifespan potential and rates of formation of mitochondrial reactive oxygen and nitrogen species (RONS). Cell death in these disorders is directly or indirectly regulated by the intrinsic mitochondrial cell death pathway. Mitochondria are the main source of RONS production and integrate cellular stress signals to coordinate the intrinsic pathway. We propose that these two functions are intimately related and that steady-state RONS-mediated signaling or damage to the mitochondrial stress-integration machinery is the principal factor setting the probability of cell death in response to a diverse range of cellular stressors. This provides a new and unifying framework for investigating neurodegenerative disorders.     

SCHEDULING IN THE SERVICE INDUSTRIES:AN OVERVIEW

Scheduling plays an important role in many different service industries.In this paper we provide an overview of some of the more important scheduling problems that appear in the various service industries.We focus on the formulations of such problems as well as on the techniques used for solving those problems.We consider five areas of scheduling in service industries,namely(i) project scheduling,(ii) workforce scheduling,(iii) timetabling,reservations,and appointments,(iv)transportation scheduling,and(v) scheduling in entertainment.The first two areas are fairly general and have applications in many different service industries.The third,fourth and fifth areas are more related to some very specific service industries,namely the hospitality and health care industries,the transportation industries(of passengers as well as of cargo),and the entertainment industries.In our conclusion section we discuss the similarities and the differences between the problem formulations and solution techniques used in the various different industries and we also discuss the design of the decision support systems that have been developed for scheduling in the service industries.     

水泥改良土力学特性试验研究

在大量动静三轴试验的基础上,研究了水泥改良土试样的应力-应变关系,掺和比及围压等影响因素,以及临界动应力、累计塑性应变、弹性应变及回弹模量的变化规律,同时,还研究了水泥土的回弹模量和动弹性应变与振动次数的变化规律.试验结果表明:水泥土的应力-应变曲线呈软化型,存在明显的应力峰值点;动应力存在一个临界值,土体的变形分为衰减型、破坏型及临界型;水泥土的临界动应力是素土的两倍以上,随掺和比的增加而增长,但增长趋势变缓.