We discuss the functional lazy techniques in generation and handling of arbitrarily long sequences of derivatives of numerical expressions in one ``variable''; the domain to which the paper belongs is usually nicknamed ``Automatic differentiation''. Two models thereof are considered, the chains of ``pure'' derivatives, and the infinite power series, similar, but algorithmically a bit different. We deal with their arithmetic/algebra, and with more convoluted procedures, such as composition and reversion. Some more specific applications of these structures are also presented.
The Virtual Garbage Collector (VGC) proposes a zone-based memory management architecture aimed at improving execution predictability and memory behavior in Python runtimes. The design explores a dual-layer model consisting of an Active VGC, responsible for managing runtime object lifecycles, and a Passive VGC, intended as a compile-time optimization layer for static allocation planning. Rather than relying on traditional heap traversal or generational heuristics, VGC introduces memory zoning and checkpoint-based state evaluation to reduce allocation churn and constrain garbage collection scope. Execution partitioning is experimentally evaluated to isolate workloads and localize memory pressure, enabling more deterministic behavior under loop-intensive, recursive, and compute-heavy workloads. This work presents the architectural principles, execution model, and experimental observations of VGC within a partition-aware runtime context. While the full realization of the dual-layer design is an ongoing effort, the results indicate that zone-based allocation and partitioned execution provide a viable foundation for improving scalability and memory predictability in Python-oriented systems.
Mostafa M. Zidan, Fikry M. Reicha, Mohamed M. Gabr
et al.
Abstract Given rise to a green chemistry, in a single step, electro-microgelation of chitosan (CS)-pullulan (PL) hybrid system self-embedded with in situ formed silver nanoparticles (AgNPs) avoiding the presence of reducing and/or crosslinking agent was prepared and introduced as a drug carrier system of losartan as a model drug. The formation, morphology, size distribution, compositional and structural features of the microgel and AgNPs have been characterized by transmission electron microscopy (TEM), UV– visible measurements (UV–vis). The compositional and structural features of the microgels were revealed by Fourier transform infrared spectroscopy (FTIR), induced coupled plasma (ICP) and Zeta potential analysis. Losartan (LOS) entrapment within the microgel network possibility was examined using UV–Vis and TEM measurements. The results revealed that a uniform AgNPs with average narrow size distribution 5.4 nm and border to border interparticle distance 1.22 nm successfully self-embedded within in situ electrosynthesised chitosan-pullulan hybrid microgels of a dual size distribution (151.4 and 43.5 nm) with a positive surface charge +25 ± 5.18 mV guarantee the electrostatic repulsion between the particles. Besides, the incorporation of AgNPs during the electrosynthesis process played a crucial role in the morphology transition from pearl-necklace to microsphere structure. Furthermore, stability examination of the colloidal microgel particles introduced that the single particle contains Ag + ions undergo a slow reduction rate in consistency with a nucleation favored over growth. On the other hand, the obtained microgel particles have a good antibacterial activity against Gram-positive and Gram-negative bacteria. Investigation of the ability of the losartan incorporation inside the microgel particles during the microgel preparation explored that a stable core/shell like structure (core: losartan and shell: AgNPs@CS/PL) was effectively formed with average size 95 nm and zeta potential +39 mV promoting the particles stability.
We give communication-based semantics and reasoning techniques for Polarized SILL, a rich session-typed programming language with general recursion. Its features include channel and code transmission, synchronous and asynchronous communication, and functional programming. Our contributions are distinguished by their faithfulness to the process abstraction, i.e., to the premise that communication is the only observable phenomenon of processes. We give the first observed communication semantics that supports general recursion and code transmission. Observed communication semantics define the meaning of processes in terms of their observed communications. We use this observational semantics to define experiments on processes, and we give a communication-based testing equivalences framework for defining observational simulations and equivalences on processes. This framework captures several natural equivalences, and we show that one of these coincides with barbed congruence, the canonical notion of process equivalence. Polarized SILL is defined using a substructural operational semantics based on multiset rewriting. To ensure that our contributions are well-defined in the presence of non-termination, we introduce fairness for multiset rewriting systems. We construct a fair scheduler, we give sufficient conditions for traces to be fair, and we study the effects of permutation on fair traces.
In program algebra, an algebraic theory of single-pass instruction sequences, three congruences on instruction sequences are paid attention to: instruction sequence congruence, structural congruence, and behavioural congruence. Sound and complete axiom systems for the first two congruences were already given in early papers on program algebra. The current paper is the first one that is concerned with an axiom system for the third congruence. The presented axiom system is especially notable for its axioms that have to do with forward jump instructions.
On Semantic Annotation in Clarin-PL Parallel CorporaIn the article, the authors present a proposal for semantic annotation in Clarin-PL parallel corpora: Polish-Bulgarian-Russian and Polish-Lithuanian ones. Semantic annotation of quantification is a novum in developing sentence level semantics in multilingual parallel corpora. This is why our semantic annotation is manual. The authors hope it will be interesting to IT specialists working on automatic processing of the given natural languages. Semantic annotation defined the way it is defined here will make contrastive studies of natural languages more efficient, which in turn will help verify the results of those studies, and will certainly improve human and machine translations.
In previous work carried out in the setting of program algebra, including work in the area of instruction sequence size complexity, we chose instruction sets for Boolean registers that contain only instructions of a few of the possible kinds. In the current paper, we study instruction sequence size bounded functional completeness of all possible instruction sets for Boolean registers. We expect that the results of this study will turn out to be useful to adequately assess results of work that is concerned with lower bounds of instruction sequence size complexity.
Each Boolean function can be computed by a single-pass instruction sequence that contains only instructions to set and get the content of Boolean registers, forward jump instructions, and a termination instruction. Auxiliary Boolean registers are not necessary for this. In the current paper, we show that, in the case of the parity functions, shorter instruction sequences are possible with the use of an auxiliary Boolean register in the presence of instructions to complement the content of auxiliary Boolean registers. This result supports, in a setting where programs are instruction sequences acting on Boolean registers, a basic intuition behind the storage of auxiliary data, namely the intuition that this makes possible a reduction of the size of a program.
For each function on bit strings, its restriction to bit strings of any given length can be computed by a finite instruction sequence that contains only instructions to set and get the content of Boolean registers, forward jump instructions, and a termination instruction. Backward jump instructions are not necessary for this, but instruction sequences can be significantly shorter with them. We take the function on bit strings that models the multiplication of natural numbers on their representation in the binary number system to demonstrate this by means of a concrete example. The example is reason to discuss points concerning the halting problem and the concept of an algorithm.
Colimits that satisfy the Van Kampen condition have interesting exactness
properties. We show that the elementary presentation of the Van Kampen
condition is actually a characterisation of a universal property in the
associated bicategory of spans. The main theorem states that Van Kampen cocones
are precisely those diagrams in a category that induce bicolimit diagrams in
its associated bicategory of spans, provided that the category has pullbacks
and enough colimits.
We study several aspects of the behaviours produced by instruction sequences under execution in the setting of the algebraic theory of processes known as ACP. We use ACP to describe the behaviours produced by instruction sequences under execution and to describe two protocols implementing these behaviours in the case where the processing of instructions takes place remotely. We also show that all finite-state behaviours considered in ACP can be produced by instruction sequences under execution.
We present a restriction of the solos calculus which is stable under
reduction and expressive enough to contain an encoding of the pi-calculus. As a
consequence, it is shown that equalizing names that are already equal is not
required by the encoding of the pi-calculus. In particular, the induced solo
diagrams bear an acyclicity property that induces a faithful encoding into
differential interaction nets. This gives a (new) proof that differential
interaction nets are expressive enough to contain an encoding of the
pi-calculus. All this is worked out in the case of finitary (replication free)
systems without sum, match nor mismatch.
Instruction sequence is a key concept in practice, but it has as yet not come prominently into the picture in theoretical circles. This paper concerns instruction sequences, the behaviours produced by them under execution, the interaction between these behaviours and components of the execution environment, and two issues relating to computability theory. Positioning Turing's result regarding the undecidability of the halting problem as a result about programs rather than machines, and taking instruction sequences as programs, we analyse the autosolvability requirement that a program of a certain kind must solve the halting problem for all programs of that kind. We present novel results concerning this autosolvability requirement. The analysis is streamlined by using the notion of a functional unit, which is an abstract state-based model of a machine. In the case where the behaviours exhibited by a component of an execution environment can be viewed as the behaviours of a machine in its different states, the behaviours concerned are completely determined by a functional unit. The above-mentioned analysis involves functional units whose possible states represent the possible contents of the tapes of Turing machines with a particular tape alphabet. We also investigate functional units whose possible states are the natural numbers. This investigation yields a novel computability result, viz. the existence of a universal computable functional unit for natural numbers.
AbstractObjective:To describe the distribution of plasma fibrinogen and relationships with other risk factors for coronary heart disease (CHD) and stroke in the black population of the Cape Peninsula.Design:A cross-sectional survey of a stratified proportional sample of randomly selected black men and women.Setting:Households in Gugulethu, Langa, Nyanga, New Crossroads, KTC, Old Crossroads and Khayelitsha in the Cape Peninsula, South Africa.Subjects:One subject per household (352 men and 447 women), aged 15–64 years, voluntarily participated. Visitors, pregnant, lactating, ill, mentally retarded and intoxicated subjects were excluded.Results:Mean fibrinogen (thrombin time coagulation method) of men and women were higher than published data for Europeans but slightly lower than values of black Americans. Women aged 45–54 years had the highest level (3.13 ± 0.89g1−1) and men aged 15–24 years had the lowest (2.13 ± 0.88g1−1). Fifteen per cent of the men and 12% of the women had a level greater than 1 standard deviation of the mean for their age group. Univariate and multivariate analyses revealed significant (P< 0.05) positive correlations of fibrinogen with smoking habit, age, body mass index (BMI), total and low-density lipoprotein (LDL) cholesterol, triglycerides, blood pressure and white blood cell count, and significant negative correlations with high-density lipoprotein (HDL) cholesterol, gamma glutamyl transferase (GGT), serum iron and ferritin. The correlations with BMI, serum lipoproteins, iron, ferritin, and GGT suggest that nutritional status and therefore diet influences plasma fibrinogen.Conclusions:Relatively high fibrinogen levels, tending to cluster with other, including diet-related, risk factors for CHD and stroke, were observed in black South Africans. It is suggested that fibrinogen may contribute to the high stroke incidence of this population group.
We describe a means of presenting hierarchically organized formal definitions of programming languages using the denotational approach of D. Scott and C. Strachey. As an example of our approach, we give the semantics of PL/CS, an instructional variant of PL/I. We also discuss the implications of this approach to language design, pointing out some cases where the wrong choices may cause the hierarchy to collapse into chaotic rubble.