27 research outputs found

    Оцінка оновлення основних засобів за рахунок позикових коштів

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    Оновлення основних засобів є актуальною проблемою сьогодення. Для багатьох підприємств кредити банків є чи не єдиним джерелом коштів на модернізацію виробничих потужностей. В даній статті нами були розглянуті можливості і перспективи приватних фірм для використання з цією метою позикових засобів, оцінений ступінь прозорості банківських установ, річні ставки за інвестиційними кредитами та інші умови їхнього надання.Modernizing of the basic assets is a topical problem of the present. For many business firms bank loans are may be the only source of funds for renewal of production facilities. In the article we have considered the opportunities and prospects for use of borrowed funds by private firms for this purpose, rated the degree of transparency of banking institutions, the annual rates of investment credits and other conditions of their granting

    On the dynamics of the adenylate energy system: homeorhesis vs homeostasis.

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    Biochemical energy is the fundamental element that maintains both the adequate turnover of the biomolecular structures and the functional metabolic viability of unicellular organisms. The levels of ATP, ADP and AMP reflect roughly the energetic status of the cell, and a precise ratio relating them was proposed by Atkinson as the adenylate energy charge (AEC). Under growth-phase conditions, cells maintain the AEC within narrow physiological values, despite extremely large fluctuations in the adenine nucleotides concentration. Intensive experimental studies have shown that these AEC values are preserved in a wide variety of organisms, both eukaryotes and prokaryotes. Here, to understand some of the functional elements involved in the cellular energy status, we present a computational model conformed by some key essential parts of the adenylate energy system. Specifically, we have considered (I) the main synthesis process of ATP from ADP, (II) the main catalyzed phosphotransfer reaction for interconversion of ATP, ADP and AMP, (III) the enzymatic hydrolysis of ATP yielding ADP, and (IV) the enzymatic hydrolysis of ATP providing AMP. This leads to a dynamic metabolic model (with the form of a delayed differential system) in which the enzymatic rate equations and all the physiological kinetic parameters have been explicitly considered and experimentally tested in vitro. Our central hypothesis is that cells are characterized by changing energy dynamics (homeorhesis). The results show that the AEC presents stable transitions between steady states and periodic oscillations and, in agreement with experimental data these oscillations range within the narrow AEC window. Furthermore, the model shows sustained oscillations in the Gibbs free energy and in the total nucleotide pool. The present study provides a step forward towards the understanding of the fundamental principles and quantitative laws governing the adenylate energy system, which is a fundamental element for unveiling the dynamics of cellular life

    It's in the loop: shared sub-surface foot kinematics in birds and other dinosaurs shed light on a new dimension of fossil track diversity

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    The feet of ground-dwelling birds retain many features of their dinosaurian ancestry. Experiments with living species offer insights into the complex interplay among anatomy, kinematics and substrate during the formation of Mesozoic footprints. However, a key aspect of the track-making process, sub-surface foot movement, is hindered by substrate opacity. Here, we use biplanar X-rays to image guineafowl walking through radiolucent substrates of different consistency (solid, dry granular, firm to semi-liquid muds). Despite substantial kinematic variation, the foot consistently moves in a looping pattern below ground. As the foot sinks and then withdraws, the claws of the three main toes create entry and exit paths in different locations. Sampling these paths at incremental horizons captures two-dimensional features just as fossil tracks do, allowing depth-based zones to be characterized by the presence and relative position of digit impressions. Examination of deep, penetrative tracks from the Early Jurassic confirms that bipeds had an equivalent looping response to soft substrates approximately 200 Ma. Our integration of extant and extinct evidence demonstrates the influence of substrate properties on sinking depth and sub-surface foot motion, both of which are significant sources of track variation in the fossil record of dinosaurs

    Central nervous system and muscular bundles preserved in a 240 million year old giant bristletail (Archaeognatha: Machilidae)

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    Among the incomparably diverse group of insects no cases of central nervous system (CNS) preservation have been so far described in compression fossils. A third of the fossil insects collected from a 240-239 million year old (Ma) level at Monte San Giorgio UNESCO World Heritage (SwitzerlandItaly) underwent phosphatization, resulting in the extraordinary preservation of soft tissues. Here we describe Gigamachilis triassicus gen. et sp. nov. (Archaeognatha: Machiloidea: Machilidae) that, with an estimated total length of similar to 80 millimeters, represents the largest apterygote insect ever recorded. The holotype preserves: (i) components of the CNS represented by four abdominal ganglia, optic lobes with neuropils and compound retina;(ii) muscular bundles. Moreover, G. triassicus, possessing morphological features that prompt its assignment to the extant archaeognathan ingroup Machilidae, places the origin of modern lineages to Middle Triassic. Interestingly, at Monte San Giorgio, in the same stratigraphic unit the modern morphology of G. triassicus co-occurs with the ancient one represented by Dasyleptus triassicus (Archaeognatha: dagger Monura). Comparing these two types of body organization we provide a new reconstruction of the possible character evolution leading towards modern archaeognathan forms, suggesting the acquisition of novel features in a lineage of apterygote insects during the Permian or the Lower Triassic

    Structures of human phosphofructokinase-1 and atomic basis of cancer-associated mutations

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    Phosphofructokinase-1 (PFK1), the “gatekeeper” of glycolysis, catalyses the committed step of the glycolytic pathway by converting fructose 6-phosphate (F6P) to fructose 1,6-bisphosphate. Allosteric activation and inhibition of PFK1 by over 10 metabolites and in response to hormonal signaling fine-tune glycolytic flux to meet energy requirements(1). Mutations inhibiting PFK1 activity cause glycogen storage disease type VII, also known as Tarui disease(2), and mice deficient in muscle PFK1 have decreased fat stores(3). Additionally, PFK1 is suggested to have important roles in metabolic reprograming in cancer(4,5). Despite its critical role in glucose flux, the biologically relevant crystal structure of the mammalian PFK1 tetramer has not been determined. We report here the first structures of the mammalian PFK1 tetramer, for the human platelet isoform (PFKP), in complex with ATP-Mg(2+) and ADP at 3.1 and 3.4 Å, respectively. The structures reveal substantial conformational changes in the enzyme upon nucleotide hydrolysis as well as a unique tetramer interface. Mutations of residues in this interface can affect tetramer formation, enzyme catalysis and regulation, indicating the functional importance of the tetramer. With altered glycolytic flux being a hallmark of cancers(6), these new structures allow a molecular understanding of the functional consequences of somatic PFK1 mutations identified in human cancers. We characterized three of these mutations and show they have distinct effects on allosteric regulation of PFKP activity and lactate production. The PFKP structural blueprint for somatic mutations as well as the catalytic site can guide therapeutic targeting of PFK1 activity to control dysregulated glycolysis in disease

    The scope and precision of specific temporal expectancy: Evidence from a variable foreperiod paradigm

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    Recent evidence from choice response time experiments with variable foreperiods (FPs) has shown that temporal expectancy can be event specific. When a certain target appears particularly frequent after one certain FP, participants tend to expect that target after that FP. This typically results in best performance for that target when it appears after that FP. In the present study, we investigated how temporally precise event-specific temporal expectancy is, and in which range of FPs it can be found. Two target stimuli were asymmetrically distributed over two “peak-FPs” and were equally distributed over 13 additional FPs. Event-specific expectancies were found for peak-FP pairs of 500/1,100 ms and 300/500 ms. Furthermore, the event expectancies generalized to a wide range of nonpeak FPs surrounding the peak FPs
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