Weakly Noether Symmetry for Nonholonomic Systems of Chetaev's Type

In the paper [J. of Beijing Institute of Technology 26 （2006） 285] the authors provided the definition of weakly Noether symmetry. We now discuss the weakly Noether symmetry for non-holonomic system of Chetaev＇s type, and present expressions of three kinds of conserved quantities by weakly Noether symmetry. Finally, the application of this new result is shown by a practical example.

Nonlinear magnitude frequency relation and two types of seismicity systems

nonlinear magnitude frequency equation has been derived in this paper on the assumption that all seismicity systems hold fractal characteristics, and according to the differences of relevant coefficients in the equation, seis-micity systems are classified into two types: type I, the whole earthquake activity is controlled by only one great unified system; type II, the whole earthquake activity is controlled by more than one great system. One type of seismicity system may convert to the other type, generally. For example, a type I system will change to a type II system prior to the occurrence of a strong earthquake in North China. This change can be regarded as an index for earthquake trend estimation. In addition, the difference between b value in nonlinear magnitude frequency equation and that in linear equation and the term dΔM related to the coefficients of nonlinear terms obtained in this paper are proved to be a pair of available parameters for medium short term earthquake prediction.

Weak Noether symmetry for nonholonomic systems of non-Chetaev type

Based on the weak Noether symmetry proposed by Mei F X, this paper discusses the weak Noether symmetry for nonholonomic system of non-Chetaev type, and presents expressions of three kinds of conserved quantities by weak Noether symmetry. Finally, the application of this new results is showed by a practical example.

T4SP: A Novel Tool and Database for Type IV Secretion Systems in Bacterial Genomes

Secretion systems, macromolecules to pass which can mediate the across cellular membranes, are essential for virulent and genetic material exchange among bacterial species[1]. Type IV secretion system （T4SS） is one of the secretion systems and it usually consists of 12 genes： VirB1, VirB2 ...VirB11, and VirD4[2]. The structure and molecular mechanisms of these genes have been well analyzed in Gram-negative strains[3] and Gram-positive strains were once believed to be lack of T4SS. However, some recent studies revealed that one or more virB/D genes also exist in some kinds of Gram-positive bacteria and play similar role, and form a T4SS-like system[3]. The VirBl-like, VirB4, VirB6, and VirD4 genes were identified in the chromosome of Gram-positive bacterium Streptococcus suis in our previous studies and their role as important mobile elements for horizontal transfer to recipients in an 89 K pathogenicity island （PAl） was demonstrated[45]. However, their structure and molecular mechanisms in other strains, especially in Gram-positive strains, are remained unclear.

THE CRITERIONS FOR ABSOLUTE STABILITY OF DIRECT CONTROL SYSTEMS OF LURIE TYPE

In this paper, we give necessary and sufficient conditions for absolute stability of several classes of direct control systems, and discuss the absolute stability of the first canonical form of control system. The corresponding results in references [3,5,6] and [7] are improved.

CLASSIFICATION OF POSITIVE SOLUTIONS TO ASYSTEM OF HARDY-SOBOLEV TYPE EQUATIONS

In this paper, we are concerned with the following Hardy-Sobolev type system{(-?)^(α/2) u(x) =v^q(x)/|y|^(t_2) (-?)α/2 v(x) =u^p(x)/|y|^(t_1),x =(y, z) ∈(R ~k\{0}) × R^(n-k),(0.1)where 0 < α < n, 0 < t_1, t_2 < min{α, k}, and 1 < p ≤ τ_1 :=(n+α-2t_1)/( n-α), 1 < q ≤ τ_2 :=(n+α-2 t_2)/( n-α).We first establish the equivalence of classical and weak solutions between PDE system(0.1)and the following integral equations(IE) system{u(x) =∫_( R^n) G_α(x, ξ)v^q(ξ)/|η|t^2 dξ v(x) =∫_(R^n) G_α(x, ξ)(u^p(ξ))/|η|^(t_1) dξ,(0.2)where Gα(x, ξ) =(c n,α)/(|x-ξ|^(n-α))is the Green's function of(-?)^(α/2) in R^n. Then, by the method of moving planes in the integral forms, in the critical case p = τ_1 and q = τ_2, we prove that each pair of nonnegative solutions(u, v) of(0.1) is radially symmetric and monotone decreasing about the origin in R^k and some point z0 in R^(n-k). In the subcritical case (n-t_1)/(p+1)+(n-t_2)/(q+1)> n-α,1 < p ≤ τ_1 and 1 < q ≤ τ_2, we derive the nonexistence of nontrivial nonnegative solutions for(0.1).

Latest developments for dry and wet dedusting systems for converter steel making

Environmental requirements world wide and in the P.R.of China in particular have increased and authorities are increasing the pressure on steelmakers to comply with always more stringent limits and standards. Modern converter steel making goes along with the innovation and new developments not only for the primary converter process itself but even more for the dedusting technologies.This paper describes the benefits and latest development of advanced off gas cleaning and recovery systems based on dry type cleaning with electrostatic precipitation and wet type gas cleaning based on wet scrubbers.Modern converter dedusting is based on suppressed combustion systems in order to reduce off gas amounts and to be able to use the gas for gas recovery.The dry type primary off gas treatment system based on electrostatic precipitator technology is the most advanced environmental solution available for converter steel making.Dry dedusting has been introduced in China successfully with a significant contribution by Siemens VAI being the market leader for converter dry dedusting systems.Siemens VAI has introduced several design improvements over the last years such as CFD modeling of flow conditions in evaporation cooler,design of chains for dust conveyors,design of ESP inlet,design and thickness of discharge electrodes and operation in energy saving mode.Additionally the DDS process has been successfully implemented in China for the De-P process.The gas recovery system for DDS has been optimized over the years with high quality equipment and integrated automation and control systems.Wet type dedusting for converter gas is a well proven technology for many years and is still widely used due to the simplicity of the process and the lower investment costs.SVAI has continuously improved it's wet dedusting technologies to provide highly energy efficient systems which can achieve lowest levels of clean gas dust while still maintaining a moderate water and energy consumption with simplified process control and standardized process control packages.Main design and process improvements include expansion joints for connection of scrubber to cooling stack,new type of droplet separator,advanced hood pressure control package,ID fan washing system,ID fan speed control system etc.The focus for wet type gas recovery systems is still on maximum safety and reliability.SVAI has also successfully improved the technological packages for converter gas recovery for wet type dedusting systems.The comparison between the two system shows the advantages of dry dedusting mainly being the lowest clean gas dust content, lower operating costs,easier handling for recycling of residuals and no need for a water treatment plants.Wet type dedusting has it's main advantages in the simple process and operation of the system,the flexible layout solutions inside the steel shop as well as generally lower investment costs.An overview on the numerous reference installations for dry- and wet type dedusting systems in China as well as world wide is given.

Characterization and Classification of Agricultural Production Systems in the Galapagos Islands (Ecuador)

The low level of agricultural productivity within the production systems in the insular region of Galapagos is caused by the lack of sustainable technologies accordingly to the insular conservation regime. As a consequence, producers face low productivity and economic losses, which result in low levels of incomes and hasten the change from agricultural to tourist activities. With consequent abandonment of productive lands, the presence of invasive species and pathogens has become a growing threat to the biodiversity of the Galapagos National Park. For this reason, it is necessary to generate and disseminate technologies adapted to the prevalent production systems in the islands. Primary data were collected through face-to-face surveys in a sample of 208 producers from 4 islands during the period from July to November 2018. Multivariate analyses (principal components and cluster) were applied to characterize and classify typical agricultural production systems. The results show three types of systems, differentiated mainly by the technology used in the management of agricultural production, that influence the yields of crops and of animal products such as beef and milk, which cannot satisfy the demand for food on the islands, which has created the dependence on imports to cover the production gap. The definition of the types of agricultural production systems can help in identifying sustainable production alternatives that integrate local social and environmental needs. This is one of the very few technical descriptions of farms on the islands and should be used by policymakers to plan interventions.

THERMAL PERFORMANCE OF FELT TYPE VEGETATED FACADE SYSTEMS IN A TEMPERATE CLIMATE DURING HEATING AND COOLING PERIODS

Using vegetated facade systems(VFS)as a sustainable solution for existing and new buildings and evaluating thermal performance of these sytems are not a new concept.However,there is a gap in literature about measuring thermal performance of VFS applied on an insulated wall.Also,in the research literature,there are few studies measuring thermal performance of felt type VFS in temperate climates,and data about the thermal performance of VFS during winter periods is still scarce.Thus,the aim of the present study is to measure the thermal performance of a felt type VFS applied on a thermal insulated existing wall that us located in Kocaeli,Turkey,under Csa climate conditions during heating and cooling periods.Test results indicate that the felt type VFS acts as a shading device and has a positive contribution to the thermal performance of building walls during a cooling period.In daytime when there is a high amount of solar radiation,felt type VFS decreased exterior surface temperatures of the insulated existing wall by a maximum of 24.4℃,32.2℃ and 37.2℃,in spring,summer and fall periods,respectively.Additionally,indoor air temperatures of the vegetated facade were lower than indoor air temperatures of the reference facade with the maximum difference of 1.8℃ during the cooling period.Also,test results indicate that the vegetated facade never dropped to below 0℃ while exterior surface temperatures of the reference facade dropped below 0℃ at nighttime in the winter period.Thus,it can be claimed that the felt type VFS behaves as a thermal buffer and enhances the thermal performance of the exterior wall of the existing building during heating periods at nighttime.As a conclusion,although differences between exterior surface temperatures of vegetated and reference walls were high,differences between interior surface temperatures of vegetated and reference walls were not meaningful.That is due to the fact that the existing building exterior wall assembly includes 5 cm thickness thermal insulation material which enhance the thermal performance of the brick wall.Finally,according to solar reflectance results,it can be claimed that vegetated facade systems have a positive effect on reducing urban heat island effect.

Feedback Stackelberg Solution for Mean-Field Type Stochastic Systems with Multiple Followers

This paper discusses feedback Stackelberg strategies for the continuous-time mean-field type stochastic systems with multiple followers in infinite horizon.First,optimal control problems of the followers are studied in the sense of Nash equilibrium.With the help of a set of generalized algebraic Riccati equations(GAREs),sufficient conditions for the solvability are put forward.Then,the leader faces a constrained optimal control problem by transforming the cost functional into a trace criterion.Employing the Karush-Kuhn-Tucker(KKT)conditions,necessary conditions are presented in term of the solvability of the cross-coupled stochastic algebraic equations(CSAEs).Moreover,feedback Stackelberg strategies are obtained based on the solutions of the CSAEs.In addition,an iterative scheme is introduced to obtain efficiently the solutions of the CSAEs.Finally,an example is given to shed light on the effectiveness of the proposed results.

Versatile and efficient mammalian genome editing with Type Ⅰ-C CRISPR System of Desulfovibrio vulgaris

CRISPR-Cas tools for mammalian genome editing typically rely on single Cas9 or Cas12a proteins.While type I CRISPR systems in Class I may offer greater specificity and versatility,they are not well-developed for genome editing.Here,we present an alternative type I-C CRISPR system from Desulfovibrio vulgaris(Dvu)for efficient and precise genome editing in mammalian cells and animals.We optimized the Dvu type I-C editing complex to generate precise deletions at multiple loci in various cell lines and pig primary fibroblast cells using a paired PAM-in crRNA strategy.These edited pig cells can serve as donors for generating transgenic cloned piglets.The Dvu type I-C editor also enabled precise large fragment replacements with homology-directed repair.Additionally,we adapted the Dvu-Cascade effector for cytosine and adenine base editing,developing Dvu-CBE and Dvu-ABE systems.These systems efficiently induced C-to-T and A-to-G substitutions in human genes without double-strand breaks.Off-target analysis confirmed the high specificity of the Dvu type I-C editor.Our findings demonstrate the Dvu type I-C editor′s potential for diverse mammalian genome editing applications,including deletions,fragment replacement,and base editing,with high efficiency and specificity for biomedicine and agriculture.

THE E^(1)_(3) TYPE OF CUBIC SYSTEMS WITH TWO INTEGRAL STRAIGHT LINES

The existence and uniqueness of limit cycle for the E 1 3 type of cubic systems with two integral straight lines has been studied in this paper. It is found that the system has no limit cycle when the two integral straight lines intersect each other; it has a unique limit cycle when the two integral straight lines are paralleled. The sufficient and necessary conditions are also given to guarantee the existence of the unique limit cycle.

Absolute Stability for Lurie Control System with Unbound Time Delays

Time delay existes widely in various real engineering systems and can result in unsatisfactory performance or even an instability of control systems. Therefore, to investigate the stability for time delay systems is of vitul importance in control theory and its applications. Many researchers have studied the stability criteria of systems with constant delay or bound varying time delay, but few of them studied large time delay or unbound time delay. Large time delay existes commonly in various engineering applications. In this paper, the absolute stability of Lurie type direct control systems and indirect control systems with several time delays are discussed. Based on Lyapunov theory, the new delay dependent absolute stability criteria are derived. In our theorem, time delays can be unbound functions, which shows that the results are less conservative than that of existed criteria.

A graph-based generic type system for object-oriented programs

We present a graph-based model of a generic type system for an OO language. The type system supports the features of recursive types, generics and interfaces, which are commonly found in modern OO languages such as Java. In the classical graph theory, we define type graphs, instantia- tion graphs and conjunction graphs that naturally iIlustrate the relations among types, generics and interfaces within complex OO programs. The model employs a combination of nominal and anonymous nodes to represent respectively types that are identified by names and structures, and de- fines graph-based relations and operations on types including equivalence, subtyping, conjunction and instantiation. Algo- rithms based on the graph structures are designed for the im- plementation of the type system. We believe that this type system is important for the development of a graph-based logical foundation of a formal method for verification of and reasoning about OO programs.

The influence of the copy number of invader on the fate of bacterial host cells in the antiviral defense by CRISPR-Cas10 DNases

Type Ⅲ CRISPR-Cas10 systems employ multiple immune activities to defend their hosts against invasion from mobile genetic elements(MGEs),including DNase and cyclic oligoadenylates(cOA)synthesis both of which are hosted by the type-specific protein Cas10.Extensive investigations conducted for the activation of Cas accessory proteins by cOAs have revealed their functions in the type Ⅲ immunity,but the function of the Cas10 DNase in the same process remains elusive.Here,Lactobacillus delbrueckii subsp.Bulgaricus type Ⅲ-A(Ld)Csm system,a type Ⅲ CRISPR system that solely relies on its Cas10 DNase for providing immunity,was employed as a model to investigate the DNase function.Interference assay was conducted in Escherichia coli using two plasmids:pCas carrying the LdCsm system and pTarget producing target RNAs.The former functioned as a de facto“CRISPR host element”while the latter,mimicking an invading MGE.We found that,upon induction of immune responses,the fate of each genetic element was determined by their copy numbers:plasmid of a low copy number was selectively eliminated from the E.coli cells regardless whether it represents a de facto CRISPR host or an invader.Together,we reveal,for the first time,that the immune mechanisms of Cas10 DNases are of two folds:the DNase activity is capable of removing low-copy invaders from infected cells,but it also leads to abortive infection when the invader copy number is high.

A Survey of Language-Based Approaches to Cyber-Physical and Embedded System Development

As computers continue to advance, they are becoming more capable of sensing, interacting, and communicating with the physical and cyber world. Medical devices, electronic braking systems in automotive applications, and industrial control systems are examples of the many Cyber-Physical Systems （CPS） that utilize these computing capabilities. Given the potential consequences of software related failures in such systems, a high degree of safety, security, and reliability is often required. Programming languages are important tools used by programmers to develop CPS. They provide a programmer with the ability to transform designs into machine code. Of equal importance is their ability to detect and avoid programming mistakes. The development of CPS has predominantly been accomplished using the C programming language. Although C is a powerful language, it lacks features present in other languages that facilitate the development of reliable systems. This has prompted research into language-based alternatives for improving program quality through the use of programming languages. This paper presents an overview of the characteristics of embedded and cyber-physical systems and the associated requirements imposed on programming languages. This is followed by a survey of relevant research into language- based methods for creating safe, reliable, and robust software for CPS.

Static typing for a substructural lambda calculus

Substructural type systems are designed from the insight inspired by the development of linear and substructural logics. Substructural type systems promise to control the usage of computational resources statically, thus detect more program errors at an early stage than traditional type systems do. In the past decade, substructural type systems have been deployed in the design of novel programming languages, such as Vault, etc. This paper presents a general typing theory for substructural type system. First, we define a universal semantic framework for substructural types by interpreting them as characteristic intervals composed of type qualifiers. Based on this framework, we present the design of a substructural calculus λSL with subtyping relations. After giving syntax, typing rules and operational semantics for λSL, we prove the type safety theorem. The new calculus λSL can guarantee many more safety invariants than traditional lambda calculus, which is demonstrated by showing that the ~.s, calculus can serve as an idealized type intermediate language, and defining a typepreserving translation from ordinary typed lambda calculus into λSL.

Behavior-Consistent Service Substitutions in Dynamic Environments

In this paper, a novel approach for service substitutions based on the service type in terms of its interface type and behavior semantics is proposed. In order to analyze and verify behavior-consistent service substitutions in dynamic environments, we first present a formal language to describe services from control-flow perspective, then introduce a type and effect system to infer conservative approximations of all possible behaviors of these services. The service behaviors are represented by concurrent behavior expressions （CBEs）. Built upon the interpretation of CBEs, behavior-consistent service substitutions are defined and analyzed by subtyping technology. The correctness of the analysis approach is guaranteed by type safety theorem, which is mechanically proved in the Coq proof assistant. Finally, applications in web services show that our method is effective and feasible.