bluuebunny/crossref_metadata_2025 huggingface dataset:
Temporal dynamics of steppe plant communities
Authors: Podpriatov O O
Published: November 2023

Global climate change affects the conditions of ecosystems. However, the nature of changes induced by climatic factors remains unknown due to the complex nature of climatic transformations. The global trend of temperature increase is associated with an increase in precipitation and changes in its rhythm. The dynamics of plant communities under the influence of climate occurs against the background of natural successional phenomena. The aim of the study is to develop methodological approaches in order to identify aspects of vegetation variability that are caused by global climate change and give them an ecological interpretation. Geobotanical descriptions of vegetation in steppe ecosystems were carried out over the last 20 years. Exactly in this period dramatic climatic changes were observed, which allows to compare climatic and vegetation trends. For ecological interpretation the results of ordination of plant communities were explained with the help of phytoindication scales. Plant communities exhibit dynamics that are driven by endogenous and exogenous causes. These aspects of community dynamics were differentiated using the ordination procedure as different ordination axes. The axes that reflect endogenous dynamics were described using temporal variables. The axes that reflect exogenous dynamics were described using phytoindication scales. The phytoindication scales made it possible to assess the ecological directions of plant community transformation under the influence of global climate change. The transformation of the plant community under the influence of global climate change is inconsistent with the concepts of desertification. The revealed temporal patterns of the plant community have a complex and multidirectional trajectory. The plant community studied over the twenty-year investigation period exhibited a dynamic that is a superposition of two processes that are driven by the temperature and precipitation. The temperature trend is directional and reflects the tendency of global warming. This trend is accompanied by an increase in species richness and projective cover of the plant community. At the same time, thermophilicity and continentality of the community increase against the decrease of soil trophic status, acidity increase and soil carbonation decrease. Obviously, along with the mineralization of organic matter, the soil decarbonization can also be the cause of increased carbon dioxide emission into the atmosphere as a result of global warming. The trend, which is regulated by precipitation, is oscillatory. This trend changes the regime of moisture, light and cryoclimate of the plant community.
The economic potential of enhanced method of anaerobic fermentation with green ammonia production for European energy market
Authors: Shapovalov Ye B , Salavor O M , Yakymenko I L
Published: November 2023

This scientific paper provides an analysis of the current state of biogas production and potential for improvement through optimizing biogas production and diversifying production. The analysis uses data from open sources and reports, such as EBA’s Statistical Report and analytical reports on market and digestate analysis. The authors present a comparison of electricity costs and biogas plant distribution in Europe, confirming that the higher the cost of electricity, the more widespread the introduction of biogas plants as an alternative energy source. The paper also discusses the potential of green ammonia production during anaerobic digestion, which can increase the efficiency and sustainability of biogas production technologies. The innovative technology of ammonia production from livestock waste during anaerobic treatment reduces the amount of water needed for dilution and transforms dissolved ammonia, which is toxic for anaerobic fermentation, into a useful final product. The paper highlights the potential for economically attractive approaches that use existing infrastructure and can contribute to energy independence and sustainability. The authors conclude that optimization in terms of more optimal process conditions and diversification of production approaches can increase the sustainability of biogas production technologies and ensure broader use.
Conceptual principles of forecasting demand on the day-ahead market using changes in hourly bidded demand between previous similar days
Authors: Polukhin A V , Evdokimov V A
Published: November 2023

On the basis of the Law on the Electricity Market adopted in 2017, the retail electricity market in Ukraine opened on January 1, 2019, and later, on July 1, 2019, the wholesale electricity market was launched. The day-ahead market (DAM) is one of the key segments of the Ukrainian electricity market. In order to implement trading strategy and successfully conduct business, to maximize the economic results in the specified market segment, it is important to understand the market situation and the structure of demand and supply. One of the indicators that must be taken into account when planning sales in the course of one’s activity is the demand for electrical energy. Currently, there are no universal algorithms in Ukraine suitable for short-term (per day) forecasting of the amount of electrical energy that will be traded on DAM. Therefore, to solve such a problem, a specialized forecasting algorithm is proposed. The basis of the developed algorithm is the possibility of considering the formulated problem in a parametric form, where, as indicators, the forecast and real data of the hourly demand on the DAM are used. At the same time, in order to find the forecast hourly demand on the market “a day ahead” – the values of the unknown indicators of the problem – an iterative method of their search is used based on statistical data of the amount of electricity purchases on the DAM, using the principle of multi-iteration analysis of changes in demand for previous similar days. The proposed algorithm is implemented in the MS Excel package, which indicates its versatility and ease of use. The high speed of obtaining a solution to the formulated problem is shown.
Energy efficient computing by using of software optimization aimed on execution time
Authors: Chemerys O A , Sushko S V
Published: November 2023

Despite of all hardware capabilities, optimization of software always was one of actual tasks. Usually optimization of software was aimed to reduce an execution time. But recent decades it’s possible sometimes also to reduce energy consumption and/or energy efficiency of computing because of enhanced energy saving capabilities. Indeed, if computations are made faster, CPU can suspend unusual computational and control blocks. In case of parallelization which is one of optimization techniques, power consumption can raise in short periods of computations because of using multiple CPUs simultaneously. At once execution time can be decreased dramatically so energy efficiency of computing still increasing. In the paper the authors provide the experiments on small size mini PC Raspberry Pi 3B which show that using of optimization tiling method not only speed up a processing but also increase energy efficiency of computing. For such low power systems this can be useful to increase power on time with a battery power source.
Method of operative determination of the stability of circulating water with regard to the release of CaCO3
Authors: Kochmarskii V Z , Moshynskyi V S
Published: November 2023

Sediments on the technological surfaces of the recirculating water supply system (RWSS) of enterprises are considered. The kinetic equation for the activity concentration of the main sediment component – Ca2+ ions in circulating water (CW) is discussed. Based on this equation, expressions were obtained for the rate of formation of CaCO3 from CW and the stability index of CW, which is expressed by the activity concentration of free Ca2+ ions not bound in CaCO3. These values are determined by measuring parameters of the quality of CW and the mode of operation of the recirculating system, which are provided for by the regulations for the operation of the RWSS Current information on the value of the stability index makes it possible to calculate the rate of CaCO3 precipitation and, if necessary, to develop quantitative parameters of operational measures to stabilize CW. The algorithm for calculating the stability index was applied to the RWSS of one of the HPPs, where softening of the feed water and bypass softening of CW are used. The calculated value of the index adequately reflects changes in the stability of the CW during variations in the operation mode of the RWSS. The stability index was used to calculate the parameters of CW acidification, which ensure the desired level of its stability.
Automatic method of preparation of data for setting the model of the electric network mode when constructing the mnemonic diagram of the object for the simulator
Authors: Liepatiev A O , Samoylov V D
Published: November 2023

The article is devoted to an automatic data preparation method for setting up a distribution network model, which is used to develop training tasks for distribution network personnel. The main goal in creating the method is to reduce the time for developing a simulator task by leveling the human error during the stage of filling in the structural data of the distribution network components. To interact with the automatic method and the already pre-created component library that was used in the previous method, it was necessary to change the internal structure of the double winding and three winding transformer components. Also, a new structural component was added to the library – Connection. The program algorithm of the automatic method consists of three cycles that go through all the components transferred from the library to the distribution network model. For a better understanding and perception of textual information about each cycle, a graphical representation of cycle process diagrams is presented. In conclusion, information is provided on the time spent when creating a task with manual data preparation and the developed automatic one, as well as suggestions to reduce computer resourced used during model run.
Studying the interaction process of a solid particles flow with the hydraulic classifier flowing part
Authors: Bondarenko A O , Shustov O O , Adamchuk A A
Published: November 2023

The paper provides a theoretical description of the solid particles movement process along with the horizontal flow of slurry within the hydraulic classifier flow part. Three modes of movement of solid particles are described: deceleration relative to the slurry flow at a constant speed or its increase, acceleration relative to the slurry flow at a decrease in its speed, with the speed of the slurry flow. The complex equation of solid particles motion in a horizontal co-flow of liquid. A graphic description of the process is given. A laboratory installation was developed to study the interaction of the hydraulic classifier flow part with the slurry flow. Experimental studies were carried out and quantitative process parameters were determined during the movement of rolled quartz solid particles in the size range < 1.8 mm and < 0.2 mm. For the first time in crisis economic conditions, in order to confirm the reliability of previously obtained analytical dependencies to determine the rational parameters of hydraulic disintegrators and determine the operational characteristics of equipment, full-scale experimental studies of the JPD 300-120 suction dredger equipped with an innovative ejector soil suction head with a jet disintegrator system were carried out.
Devices for automatic control of the quantity and quality of oil in tanks
Authors: Jabiyeva A , Isgandarova G
Published: November 2023

Currently, the most widely used devices for measuring the level of liquids (float and non-float). Float gauges are generally more accurate than non-float gauges. However, the operating conditions of float level gauges are much more difficult due to the difficult operating conditions of floats in an aggressive environment with a large amount of mechanical impurities. Automation tools used to measure the weight of oil and oil products should provide output information in a form convenient for further processing, at the same time, these devices should be structurally simple and applicable to existing types of tanks. The amount of oil in tanks can be determined in two ways: by measuring the level of oil and its specific gravity; by direct measurement of the weight of a liquid. Each of these methods has its own advantages and disadvantages. Currently, the most widely used devices for measuring the level of liquids (float and non-float). Float gauges are generally more accurate than non-float gauges. However, the operating conditions of float level gauges are much more difficult due to the difficult operating conditions of floats in an aggressive environment with a large amount of mechanical impurities. The choice of this or that device is determined by the specific conditions of its operation, the required measurement accuracy, aggressiveness of the liquid, etc. Limit switches are installed on the level gauge, which, when the liquid level in the tank reaches the upper or lower limit mark, turn on the alarm circuit. The principle of operation of the level gauge is based on measuring the increase in the electrical capacitance of sensors when they are filled with a substance (oil product) that has a dielectric constant that is different from the dielectric constant of air. The measurement accuracy is achieved by the fact that the entire measured level is divided into separate equal sections and is determined, among other factors, by the length of each section.
Improving the system for ensuring the safety of workers in the mining industry on the basis of risk management
Authors: Yevtushenko N S , Tverdokhliebova N Y , Ponomarenko O I , Zapolovskyi M Y , Yevtushenko Y D
Published: November 2023

The unfavorable situation that has developed in the economy due to the war in Ukraine, the difficult working conditions of workers in the mining industry, the lack of efficiency of labor protection measures taken lead to an increase in the level of occupational morbidity among employees of enterprises. The need for safety requires the setting of tasks, within which it is necessary to conduct a detailed analysis of a specific production activity, identify its inherent dangers and develop effective measures to protect the personnel. The purpose of the work is to develop a system of events for improving the level of safety in the mining industry on the basis of risk management, which will reduce the dynamics of occupational diseases at work. The importance of the work is in the implementation of a systematic analysis of the harmful production factors impact, taking into account working conditions, the intensity and duration of these factors impact on miners throughout their work experience in order to prevent, timely diagnose, and treat patients with occupational diseases. The introduction of methods and techniques to improve the level of safety at mining enterprises will ensure a decrease in the level of occupational morbidity among workers.
Information system of multi-stage analysis of the building of object models on a construction site
Authors: Dolhopolov S , Honcharenko T , Terentyev O , Predun K , Rosynskyi A
Published: November 2023

This study focuses on the development of a multi-stage analysis of building object models (BOM) on a construction site for modeling an “evolutionary” digital twin, by integrating building information modeling (BIM) technology and an artificial intelligence system. The concepts of photo modeling of the construction site using a group of moving cameras were outlined, as well as the possibility of integrating IoT technologies. The dynamic transition of real building structures into intermediate BIM representations of digital twins was investigated, with the prospect of enabling augmented reality technology. An artificial intelligence system combining Convolutional Neural Network (CNN) and Feed Forward Neural Network (FFNN) architectures has been developed as a comprehensive mechanism for the detection, categorization, and evaluation of BIM projects at all stages of their life cycle. The paper addresses the scaling prospects for the development of point cloud and mesh models, as well as the use of big data technology while optimizing the representation of the “evolutionary” BIM project of the digital twin of the construction site. The effectiveness of site conformance detection during the step-by-step construction of a BIM model, which shows consistency and provides a quantitative assessment of the processes occurring on the site, has been determined. The results of this research can be used to improve BIM modeling methods and concepts, in particular towards a multi-stage “evolutionary” representation of the digital twin of the construction site.
Development of the hydrological regime of the Uzh River under backwater conditions to minimize the urban environment risks
Authors: Velychko S V , Dupliak O V
Published: November 2023

The impact of high dams with large reservoirs with long-term regulation is covered in the scientific literature quite widely. The information and recommendations on the use of low-head dam for the creation of the low backwater are not enough. Large dams reduce the mean annual flow downstream, the magnitude and frequency of floods, lead to the accumulation of suspended solids, nutrients compounds (nitrogen, potassium, phosphorus), which, together with increasing temperature leads to the “blooming” phenomenon of the reservoir and the overgrowth, create barrier for sediments transferring and fish. The main reason of the deterioration of the water quality is the water retention time in the formed reservoir and anthropogenic pollution, although the literature rarely provides quantitative data of the water retention time for the evaluated reservoir. The environment risks assessment of the impact of the reservoir should include the calculation of the water retention time, the presence of pollutants in the river, which may indicate future negative effects. The hydrological regime of the river after the backwater creation should correspond to the natural flow with the floods passage by the entire width of the river bed, which will significantly improve flood management, sediments transport and washing the river bed. The significant risk is the shallowing of the river downstream, the amount of water discharged into the downstream should be at least 75% of the river flow. Releasing the flow to the downstream with an overflow or through fish passage structures allows to enrich the water with oxygen. In order to preserve biodiversity, it is necessary to create or leave islands and shallow water areas for the needs of waterfowl. To ensure an environmentally friendly regime operation of the low-head dam the crest of the spillway structure should be at the bottom level along the entire cross section. The low-head dam should be provided with automatic control system and communication with the hydrometric station for a quick response to the flow changes in the river.
Improvement technology of water regulation and methods of calculating the parameters of modular drainage systems on the lands of the humid zone
Authors: Tkachuk M M , Klimov S V , Khlapuk M M , Tkachuk R M
Published: November 2023

The article examines water regulation on drained lands by innovative modular drainage systems with multi-level connection of regulating drains, diagrams of their design parameters are given. The main goal of the article is to demonstrate the results of analytical studies of water regulation by drainage modules under the condition of laying drains at different depths are given. The equations derived in this article allow you to use them to calculate the distance between regulating drains of different installation depths, perfect in terms of the degree and nature of the opening of the aquifer during infiltration water supply within drainage modules. Variants of the application of methods for calculating the parameters of regulatory drainage modules are proposed, which allow predicting groundwater level regimes, establishing watershed lines between perfect shallow-deep drains.
Quantitative assessment of water quality in the Vidsichne reservoir (Zhytomyr, Ukraine)
Authors: Skyba G , Kolodii M
Published: November 2023

The modern approach to the implementation of water management activities is based on a quantitative assessment of the quality of water resources, which includes a certain set of indicators to reflect the needs of users in the composition and properties of water, to assess their condition, etc. Ecological assessment is a preliminary stage and a condition for ecological standardization of surface water quality. To analyze the compliance of water quality with ecological standards, the obtained results are compared with the values of ecological standards for the corresponding water body. The study carried out a quantitative assessment of water quality in the Vidsichne reservoir, near Zhytomyr (Ukraine). This assessment is based on the introduction of risk weighting factors from certain types of pollutants to the calculation formula of the integral indicator. Monitoring studies on hydrochemical indicators in the reservoir showed an increase in manganese content to 0.40 mg/dm3. To calculate the integral indicator of water quality, manganese and the related level of oxygen dissolved in water, biological oxygen consumption (BOC) were selected. It was established that the water in the reservoir belongs to the fourth quality class, that is, it is polluted. A model map of manganese concentration was built and the ecological coefficient of water quality was calculated, which indicates a 5-fold excess of ecological standards. The use of a graphic method of comprehensive assessment of the state of water in any reservoir is substantiated. The increase in manganese content is due to the seasonal increase in air temperature. The constructed mathematical model of the dependence of manganese content on temperature makes it possible to predict the state of the water body depending on climatic conditions and indicates an increase in the value of this indicator from 12°C and above. Quantitative assessment of water quality in the reservoir based on the sum of ecological indicators reflects the needs of users in the composition and properties of water and makes it possible to assess their condition.
Methodology for determining the availability of natural moistening of the territory by hydrometeorological conditions for the needs of land reclamation
Authors: Tkachuk A V , Tkachuk T I
Published: November 2023

The paper considers one of the important problems of water use – determination of the humidification conditions of the territory for the hydromelioration needs. The methodical approach to determining the probability of exceeding natural moisture by a group of criteria is highlighted. Nowadays there is no single, reliable and simple method for determining this indicator. Assessing climatic conditions, considering their impact on crop productivity, it is necessary to take into account hydrometeorological factors that have a decisive influence on the development of crops and, accordingly, determine their yield. These include, first of all, precipitation, moisture reserves in the soil, evapotranspiration and other complex indicators that allow to take into account the distribution of meteorological factors during the growing season of the crop and their possible negative impact on the development of the plant, because each crop requires a certain optimal regime of soil temperature and moisture at different stages of its development. The article presents the solution of the set tasks on the example of winter wheat crops according to the data of the Dnipro meteorological station (airport).
Cadastral and landscape modeling of lakes as a prerequisite for protected and recreational nature resource management
Authors: Martyniuk V O , Korbutiak V M , Zubkovych I E
Published: November 2023

The cadastral information about the lakes of the nature reserve fund (NRF) should be based on landscape-geographic principles using modern geo-information systems.Within the research, based on the instrumental field research and the use of software packages ArcGIS Desktop and ReefMaster Software, a bathymetric map of Lake Serednie (Nobel National Natural Park, Ukraine) and other spatial models were developed. The main hydrological and morphometric parameters of the lake basin were calculated, a landscape map of the natural aquatic complex was created and its landscape metric analysis was carried out at the level of aquatic tracts and facies. The research revealed changes in the level regime and shoreline of the lake caused by the long dry periods of 2016-2021 and life activity of beavers. The created integrated cadastral landscape model of the lake with limnology parameters should serve as a basis for the recreational nature use, monitoring and geo-ecological certification of the reservoirs of the NRF.
Development of a conceptual scheme for the creation of environmentally friendly Gd-containing neutron-absorbing nanocomposites
Authors: Kovach V O , Kutsenko V O , Pylypchuk Ie V , Krasnov Y B , Bliznyuk V N , Budnyak T M
Published: November 2023

The nature and properties of neutron radiation impose specific requirements on the creation and operation of such materials. The presence of accompanying and induced radiation, weather conditions, as well as the peculiarities of the location of functional layers require a hierarchical approach to the development of such neutron-absorbing materials. It was shown that the conceptual scheme of creating Gd-containing protective materials consists in taking into account all factors of their operation. In particular, it is shown that the presence of neutron-absorbing components is a necessary but not sufficient condition for their successful application in environmental conditions. In this work, Gd-containing chitosan films were prepared as an example of the proposed conceptual scheme for the creation of environmentally friendly neutron-absorbing nanocomposites. The prepared Gd films were characterized and their neutron permeability was estimated. The approach presented in this work contributes to the development of sustainable and responsible production practices, supporting SDGs 9 and 12.
Selection of the optimal option for the transformation of the “Shelter” object into an environmentally safe system using the factor-criterion model of scenario analysis
Authors: Skiter I , Saveliev M , Molitor N , Derenhovskyi V , Kaftanatina O
Published: November 2023

The paper presents a comprehensive analysis of potential scenarios for Shelter Object transformation into an environmentally safe system after the commissioning of the New Safe Confinement. The analysis of scenarios is based on the developed factor-criteria model, which includes two groups of indicators in the scenario assessment: groups of factors and sets of criteria for each factor. The assessment of a separate scenario is carried out using the global value indicator. The global value of the scenario is determined taking into account the criterion content of all assessment factors. Characteristics of groups of factors and their criteria were determined by means of peer review. The assessment of the global values of scenarios allowed us to rank them. Based on the analysis, the most reasonable and realistic strategy for the phased removal/transfer to a controlled state of fuel-containing materials was proposed. The strategy also includes processes for further management of these materials and associated radioactive waste. As well as “Shelter” Object transformation processes in the process of its transformation into an environmentally safe system and determination of its final state. Based on the results of the comparative analysis of scenarios, it was found that the scenario that provides for the removal of known accumulations of fuel-containing materials during the life cycle of the New Safe Confinement is optimal if the activities on the phased retrieval of fuel-containing materials are properly financed.
Neural network model of investment process of biogas production
Authors: Dzhedzhula V V , Yepifanova I Yu
Published: November 2023

The paper forms a neural network model of the investment process of biogas production, which allows increasing the efficiency of the management decision-making process on the feasibility of investing in biogas plants. Biogas plants are becoming widespread in the world, although natural climatic conditions are not favorable for biogas production. But modern technological solutions for insulation of bioreactors, their automation and thermal stabilization, allow obtaining biogas in different latitudes. The construction of biogas plants requires significant capital investment. Therefore, these investments require a detailed feasibility study, including consideration of both technical and economic aspects of biogas production. The authors propose to use the mathematical apparatus of shallow neural networks and create a ten-neuron shallow neural mathematical model with the MATLAB mathematical package, which can serve as a tool to support investment decisions in the implementation of the biogas plant project. The proposed model, in contrast to existing approaches, allows us to take into account both quantitative and qualitative factors, which are obtained analytically, expertly and experimentally. In addition, the proposed model allows combining both economic and technical criteria that affect the decision-making process for investing in the process of biogas production. The calculation of investment attractiveness of introduction of biogas utilization unit for the researched enterprise is given. According to the simulation results, it is determined that the investment attractiveness of the introduction of a biogas plant for the given set of input factors indicates the feasibility of implementing a biogas plant.
Characteristic investigations on bio-silica gel prepared from teff (Eragrostis tef) straw: effect of calcination time
Authors: Tessema Belete , Gonfa Girma , Hailegiorgis Sintayehu Mekuria , Venkatesa Prabhu Sundramurthy
Published: November 2023

Bio-based silica gel is having many commercial significances in various sectors, such as medical, cleansing agents in industries, laboratory analysis, cosmetics, food additives, and so forth. In view of crucial requirements, this study aimed to synthesize and characterize the silica gel from Ethiopia’s primary post-harvest biomass residue, known as teff straw. The present study has been emphasized to investigate on the influence of calcination time for teff straw ash [Joshi et al 2022 Investigation of bamboo leaves as an alternative source of silica: extraction, characterization and its application as an adsorbent for methylene blue sequestration Chem. Select.
7, e202200011] preparation between 2 to 5 h. Further, the specific surface area of the resultant TSA samples was examined for preliminary understandings of processing time. By adopting the standard procedures through template-mediated sol–gel process, acquired TSA samples were subjected to treatment with NaOH to result sodium silicate solution and the amorphous silica. From the findings, it was apparent that the yield of silica gel has significantly influenced by calcination time. Accordingly, the maximum yield (90.0%) was attained at the calcination time of 4 h at 900 °C. Further, physiochemical and morphological characteristics of acquired silica gels were ascertained using sophisticated instrumental techniques such as BET, FTIR, XRD, SEM, and EDX. The XRD analysis of the crystallographic characteristics showed that the silica extracted from TSA at 900 °C for 2, 3, 4, and 5 h was found to be in amorphous state. The surface morphological studies of silica gel samples have been carried out using SEM studied. the EDX spectra showed the negligible amount of other impurities, nevertheless a larger amount of silica was found with highest purity of 99.77% e silica gel was obtained in TSA calcinated at 3 h. FTIR spectrum confirmed the presence of siloxane (Si–O–Si) vibrations of amorphous silica that are responsible for the strong bend observed at 1070 cm−1. It was found that the silica gel prepared at 3 h of calcination time had the largest specific surface area of 739.242 m2 g−1, pore volume of 0.32 cm3 g−1, and a pore diameter of 1.68 nm.
Holomorphic Hörmander-type functional calculus on sectors and strips
Authors: Haase Markus , Pannasch Florian
Published: November 2023

In this paper, the abstract multiplier theorems for

0
0

-sectorial and

0
0

-strip type operators by Kriegler and Weis [Math. Z. 289 (2018), pp. 405–444] are refined and generalized to arbitrary sectorial and strip-type operators. To this end, holomorphic Hörmander-type functions on sectors and strips are introduced, with even a finer scale of smoothness than the classical polynomial scale. Moreover, we establish alternative descriptions of these spaces involving Schwartz and “holomorphic Schwartz” functions. Finally, the abstract results are combined with a result by Carbonaro and Dragičević [Duke Math. J. 166 (2017), pp. 937–974] to obtain an improvement—with respect to the smoothness condition—of the known Hörmander-type multiplier theorem for general symmetric contraction semigroups.
Optimal error estimates of ultra-weak discontinuous Galerkin methods with generalized numerical fluxes for multi-dimensional convection-diffusion and biharmonic equations
Authors: Chen Yuan , Xing Yulong
Published: November 2023

In this paper, we study ultra-weak discontinuous Galerkin methods with generalized numerical fluxes for multi-dimensional high order partial differential equations on both unstructured simplex and Cartesian meshes. The equations we consider as examples are the nonlinear convection-diffusion equation and the biharmonic equation. Optimal error estimates are obtained for both equations under certain conditions, and the key step is to carefully design global projections to eliminate numerical errors on the cell interface terms of ultra-weak schemes on general dimensions. The well-posedness and approximation capability of these global projections are obtained for arbitrary order polynomial space based on a wide class of generalized numerical fluxes on regular meshes. These projections can serve as general analytical tools to be naturally applied to a wide class of high order equations. Numerical experiments are conducted to demonstrate these theoretical results.
Extended Nullstellensatz proof systems
Authors: Krajíček Jan
Published: November 2023

For a finite set

F

\mathcal {F}

of polynomials from

F

p

[

x
¯

]

{\mathbf {F}_{p}[\overline x]}

(

p
p

is a fixed prime) containing all polynomials

x
2

−
x

x^2 - x

, a Nullstellensatz proof of the unsolvability of the system

f
=
0
,
 all 
f
∈

F

\begin{equation*} f = 0, \text { all } f \in \mathcal {F} \end{equation*}

in

F

p

\mathbf {F}_{p}

is an

F

p

[

x
¯

]

{\mathbf {F}_{p}[\overline x]}

-linear combination

∑

f
∈

F

 

h
f

⋅
f

\sum _{f \in \mathcal {F}} \ h_f \cdot f

that equals to

1
1

in

F

p

[

x
¯

]

{\mathbf {F}_{p}[\overline x]}

. The measure of complexity of such a proof is its degree:

max
f

d
e
g
(

h
f

f
)

\max _f deg(h_f f)

.

We study the problem to establish degree lower bounds for some extended NS proof systems: these systems prove the unsolvability of

F

\mathcal {F}

(in

F

p

\mathbf {F}_{p}

) by proving the unsolvability of a bigger set

F

∪

E

\mathcal {F}\cup \mathcal {E}

, where the set

E

⊆

F

p

[

x
¯

,

r
¯

]

\mathcal {E}\subseteq {\mathbf {F}_{p}[\overline x, \overline r]}

contains all polynomials

r
p

−
r

r^p - r

and satisfies the following soundness condition: Any

0
,
1

0,1

-assignment

a
¯

\overline a

to variables

x
¯

\overline x

can be appended by an

F

p

\mathbf {F}_{p}

-assignment

b
¯

\overline b

to variables

r
¯

\overline r

such that for all

g
∈

E

g \in \mathcal {E}

it holds that

g
(

a
¯

,

b
¯

)
=
0

g(\overline a, \overline b) = 0

. We define a notion of pseudo-solutions of

F

\mathcal {F}

and prove that the existence of pseudo-solutions with suitable parameters implies lower bounds for two extended NS proof systems ENS and UENS defined by Buss et al [Comput. Complexity 6 (1996/97), pp. 256–298]. Further we give a combinatorial example of

F

\mathcal {F}

and candidate pseudo-solutions based on the pigeonhole principle.
A 𝐶*-algebra of entire functions
Authors: Ma Pan , Zhu Kehe
Published: November 2023

We study the maximal abelian von Neumann algebra corresponding to

L
∞

(

R

)

L^\infty (\mathbb {R})

via the Bargmann transform. It is naturally an algebra of operators on the Fock space

F
2

F^2

, but it can also be realized as a function algebra contained in

F
2

F^2

. This provides an interesting example of a

C
∗

C^*

algebra whose elements are analytic functions.
The inhibition of inner mitochondrial fusion in hepatocytes reduces non-alcoholic fatty liver and improves metabolic profile during obesity by modulating bile acid conjugation
Authors: Da Dalt Lorenzo , Moregola Annalisa , Svecla Monika , Pedretti Silvia , Fantini Francesca , Ronzio Mirko , Uboldi Patrizia , Dolfini Diletta , Donetti Elena , Baragetti Andrea , Mitro Nico , Scorrano Luca , Norata Giuseppe Danilo
Published: November 2023

Aims

Mitochondria are plastic organelles that continuously undergo biogenesis, fusion, fission, and mitophagy to control cellular energy metabolism, calcium homeostasis, hormones, sterols, and bile acids (BAs) synthesis. Here, we evaluated how the impairment of mitochondrial fusion in hepatocytes affects diet-induced liver steatosis and obesity.

Methods and results

Male mice selectively lacking the key protein involved in inner mitochondrial fusion, optic atrophy 1 (OPA1) (OPA1ΔHep) were fed a high fat diet (HFD) for 20 weeks. OPA1ΔHep mice were protected from the development of hepatic steatosis and obesity because of reduced lipid absorption; a profile which was accompanied by increased respiratory exchange ratio in vivo, suggesting a preference for carbohydrates in OPA1ΔHep compared to controls. At the molecular level, this phenotype emerged as a consequence of poor mitochondria-peroxisome- endoplasmic reticulum (ER) tethering in OPA1 deficient hepatocytes, which impaired BAs conjugation and release in the bile, thus impacting lipid absorption from the diet. Concordantly, the liver of subjects with non-alcoholic fatty liver disease (NAFLD) presented an increased expression of OPA1 and of the network of proteins involved in mitochondrial function when compared with controls.

Conclusion

Patients with NAFLD present increased expression of proteins involved in mitochondrial fusion in the liver. The selective deficency of OPA1 in hepatocytes protects mice from HFD-induced metabolic dysfunction by reducing BAs secretion and dietary lipids absorption as a consequence of reduced liver mitochondria-peroxisome-ER tethering.
Nicotine dependency: animal studies
Authors: Swedberg Michael D B , Henningfield Jack E , Goldberg Steven R
Published: November 2023

A central requirement in definitions of drug dependence is that a dependence- producing drug will engender behaviour aimed at securing additional quantities of the drug for consumption (Edwards et al. 1982; Meisch and Thompson 1974; Spealman and Goldberg 1978). Other concomitants may include the development of tolerance to effects of the drug, and withdrawal syndromes that occur when drug administration is discontinued. Strategies developed in behavioural pharmacology have led to the development of experimental animal models for human drug taking behaviour; such models have been used to generate a substantial body of data on the major pharmacological groups of dependence-producing drugs. An important distinction to be made is that physiological dependence (characterized by onset of a withdrawal syndrome when drug administration is discontinued) may be present, but is not a necessary component in the maintenance of self-administration behaviour. For example, even drugs which are capable of producing severe physiological dependence when high enough doses are taken (such as the opiates, alcohol, and barbiturates) may maintain self-administration behaviour when drug doses and frequency of access are employed which prevent the development of demonstrable physiological dependence (Goldberg 1976). This chapter will review and discuss recent studies of nicotine self- administration with emphasis on methodological and interpretive issues, studies which have led to variable interpretations of data regarding the efficacy of nicotine in maintaining self-administration behaviour in animals. The potential of nicotine to produce tolerance with chronic exposure, and withdrawal symptoms upon termination of chronic exposure, will also be reviewed.
Direct Reactions
Authors: Gadioli E , Hodgson P E
Published: November 2023

Direct reactions begin immediately the incident particle encounters the target nucleus, and occur in the time it takes to traverse the nuclear field. The simplest direct process is elastic scattering, and this is described briefly in Section 4.2. It is also possible for the incident particle to give energy to the target nucleus, leaving it in an excited state. This is inelastic scattering, described in Section 4.3. Next in order of increasing complexity are the nucleon transfer reactions (Section 4.4) and the knock-out reactions (Section 4.5).
Experimental approaches for the development of pharmacological therapies for erectile dysfunction
Authors: Foreman Mark M
Published: November 2023

During the past fifteen years, both academic and pharmaceutical laboratories have targeted major research efforts in the physiology, pathophysiology, and pharmacology of sexual response. The discoveries stemming from this research have in turn resulted in a variety of clinical trials using different therapeutic strategies for sexual disorders in both men and women. These sexual disorders include dysfunctions of the desire, arousal, and orgasmic phases of the sexual response cycle as described by Kaplan (1979). These phases cover the full range of sexual responses starting with the integration of sensory inputs with cognitive, emotional, and desire components for the initiation of sexual activity; progressing to the vasocongestion of the genitalia; and terminating with the physiological and perceptual changes associated with orgasm. The following review will focus on one of these disorders, erectile dysfunction in the male, and will outline some of the characteristics of the pathophysiology, the patient population, and the experimental approaches for the development of pharmacotherapies.
The nature of human sexual desire and its modification by drugs
Authors: Kellett John
Published: November 2023

There are various ways of classifying sexual desire, and even more ways of attempting to measure it. Intrapsychically it is manifest by a sensitivity to sexual stimuli, preoccupation with sexual fantasies, and/or a longing to be with the preferred partner. Physiologically there is a lowered threshold for genital engorgement which may only be relieved by orgasm. The relation between physical and psychological changes is complex, which prevents one making any clear assessments of the libido from physical arousal. Certainly the physical and psychological changes react with each other in the manner of a feedback loop, the feeling of genital engorgement leading to psychic arousal and vice versa. There are several difficulties in assessing sexual desire.
Psychiatric drugs and sexuality
Authors: Barnes Thomas R E
Published: November 2023

Knowledge about the effects of psychiatric drugs on sexual function is relevant for two main reasons. First, familiarity with the possible sexual side-effects of a particular drug is necessary if the adverse effects are to be adequately monitored in an individual patient or clinical trial. Second, if a patient presents with a sexual dysfunction, information on drug-induced sexual problems is required in order to assess the possible contribution of their current medication and drug history.
Natural calcium-sensitizing compounds of the heart
Authors: Mil/er D J , Lamont C , O’dowd J J
Published: November 2023

‘Calcium sensitivity’ is the term used to describe the apparent relationship between [Ca2+] and the state of activity (usually reported as relative force) produced by the contractile system of the heart. The sensitivity of the contractile proteins to calcium is strictly apparent since it is defined by a plethora of conditions prevailing inside the cell. Some, such as the intracellular colligative properties, are essentially invariant in vivo.
The effects of caffeine on cardiac muscle
Authors: O’Neill S C , Donoso P , Lamont C , Eisner D A
Published: November 2023

Work on skeletal muscle has shown that caffeine at low concentrations (less than 5 mmol/1) potentiates the twitch while at higher concentrations it causes a maintained contraction. Various actions of caffeine have been reported in the heart It has been found, for example, that caffeine can prolong the twitch while reducing its magnitude or increase the size of the twitch while still prolonging the duration. Caffeine has also been found to cause a wholly or partially transient increase in the size of the twitch with, in the former case, no effect on the duration of the underlying calcium transient. As in skeletal muscle, caffeine can cause a contraction in unstimulated cardiac muscle although this is not always seen. In this review it is shown that these very different effects of caffeine can all be explained in terms of the mechanisms listed above.
Fetal growth and development: the role of nutrition and other factors
Authors: Perry Ivan J
Published: November 2023

It is hypothesized that the risk of cardiovascular disease and diabetes in adult life is programmed in utero by specific patterns of abnormal fetal growth associated with maternal undernutrition. This hypothesis raises fundamental questions about patterns of fetal growth in utero and about the role of factors other than nutrition in fetal growth and development. An unambiguous concept of nutrition that relates to the mother’s diet, growth, and development in childhood, and her diet during pregnancy, facilitates the testing of precisely formulated hypotheses in work on nutrition, fetal growth and adult disease. Different patterns of fetal growth retardation in pregnancy form a continuum that depends mainly on the severity and timing of thenutritional or other insult. Growth failure in the third trimester tends to be asymmetrical, with weight loss but a relative sparing of fetal length. The hypothesis that nutritional insults in early pregnancy set the fetus on a low growth trajectory leading to symmetrical growth retardation is less securely based. The concept of nutritional programming is undoubtedly plausible in biological terms. However, a less discrete and deterministic model of programming is proposed, involving interactions between the maternal and fetal genotype, the mother’s environment and life style (including diet), her prepregnancy nutritional status, metabolism and physiology, the hormonal, metabolic and circulatory milieu which sustains fetal growth and the infant’s postnatal environment. The effects of prenatal nutrition on fetal growth in man depend on the timing of nutritional exposures in relation to critical periods of development and on interactions with the mother’s prepregnancy nutritional status and aspects of the mother’s metabolism and physiology such as glucose tolerance and blood pressure.