Turnover Values Research Articles

Сравнение годовых грузооборотов железнодорожного и автомобильного транспортов РФ: моделирование, верификация, точечный и интервальный прогноз

Purpose: a study was conducted comparing the freight turnover of rail and road transport in the Russian Federation over the last twenty years and a forecast assessment was made. The comparative assessment was carried out due to the excess of freight turnover by rail over road transport. The study includes the following main stages: modeling based on the observed annual values of cargo turnover; model verification by comparing model and experimental values in years not involved in the construction of the model; model point and interval forecasting; analysis of the forecast trend of changes. The mathematical model of the excess of freight turnover by rail over road transport from the year of cargo delivery is based on a sample of statistical data from Rosstat from 2004 to 2021. The model was verified based on the results of cargo turnover in 2022 and 2023. Methods: to build a mathematical model, test it and carry out forecasting, a number of theoretical provisions of econometrics were used, including dynamic series, regression analysis, the least squares method, point and interval forecasting. The applied calculation apparatus was used using the Excel PPP. Results: the quality of the constructed model was evaluated by the following indicators: approximation errors, correlation and determination coefficients, and the Fisher criterion. A comparison of the observed and model values of excess cargo turnover showed that in the period from 2004 to 2021, according to the above indicators, they have minor deviations. The verification performed confirmed the satisfactory simulation. Practical significance: the conducted research has shown that it is possible to predict the results of transport operations according to the described algorithm and it is justified to make management decisions at the beginning of their implementation. Recommendations: to continue improving the modeling and forecasting apparatus, taking into account the assessment of risk indicators.

Determination of demand for freight rail transportation. The relationship between the quality of transport services and demand

In the modern world, rail transport plays a huge role in ensuring the economic and social stability of the state. Due to its reliability, accessibility and safety, rail transport is able to meet the needs of a wide variety of population groups and sectors of the economy. One of the important aspects of the functioning of railway transport is its ability to provide efficient and high-quality cargo transportation services.In this regard, the purpose of this study is to identify the relationship between the demand for freight transportation and the level of service in the context of railway infrastructure. We rely on the non-price elasticity method to determine more precisely how changes in the quality of service can the demand for freight rail transportation.To achieve this goal, a number of tasks have been analyzed, such as analyzing the current state of railway transport, studying the possibilities of its growth and development, determining the current needs of the market and assessing the compliance of the services provided with these needs. In addition, the system of forecasting the demand for rail freight, based on the analysis of financial, economic and quantitative indicators, is considered. The first determine the capital costs of upgrading the current state of the infrastructure, focused on the repair and renewal of fixed assets. The latter determine the volume values of the cargo turnover and the average weight of the train. It is also necessary to develop a step-by-step methodology for determining the coefficient of non-price elasticity, to illustrate the dependence of demand for transportation on the level of quality of transport services.All this made it possible to determine how effective and expedient the existing cargo transportation service system is.The choice of this topic is due to the increasing need to increase the stability and reliability of railway transport, increase its accessibility and safety, as well as improve the quality of services provided. Thus, the identification of the relationship between the demand for rail freight and their quality based on the methodology of non-price elasticity contributes to the optimization of railway transport, improving its competitiveness, and stimulates the economic growth of the country.

Beta diversity patterns in Andean rodents: current and historical factors as drivers of turnover and nestedness

Abstract The Andes are known to be one of the most species-rich regions on Earth, with their origination promoting formation of new habitats and acting as climatic barriers. This orogenic event was structured latitudinally with 3 major segments having different formation times and with different environmental and historical conditions. The Andean region has been historically important in the evolutionary history of small mammals and is considered the region of Earth with the highest values of rodent species richness and turnover. Therefore, the region provides an excellent opportunity to evaluate mechanisms involved in structuring rodent assemblages and beta diversity patterns. Here, we assessed spatial patterns of rodent beta diversity along the Andes Mountains, with specific goals of examining patterns of turnover and nestedness as 2 recognized processes that drive species composition. We explored the role of spatial, climate, and historical factors on beta diversity patterns using geographic range maps for 432 rodent species to construct a species presence–absence matrix. We used piecewise regressions to identify latitudinal breakpoints in turnover and nestedness, and conducted multiple regressions and variation-partitioning approaches to assess the contribution of each set of postulated drivers in shaping beta diversity patterns. Beta diversity decreases from north to south. The highest turnover was located at the Northern Andes (5°N and 10°S) and western-central Andes (20°S and 35°S). Nestedness was higher below 40°S and in some areas of the western-central Andes between 15° and 20°S. Turnover and nestedness registered breakpoints coincident with the Central and Southern Andes limit. Turnover explained most of the beta diversity for all segments, although within the Southern Andes there was also some contribution of nestedness. In all segments, beta diversity was mainly explained by spatial factors with minor contributions from spatially structured climate (Northern Andes), interaction of all factors (Central Andes), and the interaction between current climate and history (Southern Andes).

Additive, antagonistic and synergistic interactions of future climate and land use change on Theaceae species assemblages in China

While climate and land use change are commonly known to interactively affect biodiversity worldwide, their interactive effects have rarely been explored, hindering our understanding of the attribution of biodiversity change to each of these two drivers. Here, we used ensemble species distribution models to project the potential distribution of 200 Chinese Theaceae species in the 2070s under three types of climate and land use change scenarios: (1) dynamic climate and constant land use, (2) constant climate and dynamic land use and (3) dynamic climate and dynamic land use. We further assessed the single and combined effects of climate and land use change on Theaceae species assemblages in China, and their interactive effects (i.e., additive, antagonistic and synergistic effects) on species losses and gains. Our results revealed that the mean species richness is predicted to change ranging from − 3.43–0.07 species by the 2070 s in China and the predicted species turnover values range from 1.38% to 18.65%. Additive and antagonistic interactions would dominate species losses and gains in at least 26.54% and 30.17% of the study area, respectively, while synergistical interactions would only occur in < 9.14% of the study area. Moreover, there were significant negative correlations between the single effects of land use and climate change and their interactive effects. These findings highlight the importance of understanding the interactive effects of climate and land use change on biodiversity and will help to better minimize risks of future biodiversity loss and exploit opportunities provided by land use-climate change interactions.

Environmental correlates of aquatic macroinvertebrate diversity in garden ponds: Implications for pond management

Abstract Garden ponds are a ubiquitous feature of urban landscapes and have the potential to be an important resource for biodiversity. However, the environmental and spatial factors influencing ecological communities within garden ponds have been poorly quantified to date, despite such evidence being critical to the development of effective management strategies that support biodiversity. This study aims to identify the environmental and spatial factors influencing macroinvertebrate richness, abundance and compositional variation among garden ponds and provide management recommendations at the local and landscape scale. In total, 99 macroinvertebrate taxa were recorded from 30 garden ponds. A negative association was recorded between ecological uniqueness (measured as the Local Contribution to Beta‐Diversity) and taxonomic richness among the garden ponds, and those ponds with high ecological uniqueness typically displayed high replacement (turnover) values. Surface area, total plant richness and non‐native plant richness were positively associated with macroinvertebrate richness. Taxonomic richness and abundance predominantly displayed a negative association with conductivity levels. Current management practices for garden ponds are highly variable, often focussed on individual ponds. Based on the findings of this study, we recommend that management should focus on making garden pond surface areas as large as possible, ensure that there is a wide variety of native aquatic plant species present and manage conductivity levels. Garden ponds likely comprise a significant component of the urban freshwater network, and considering their management at both local and landscape scales will ensure that biotic communities inhabiting urban landscapes can be more effectively supported.

Canopy gaps are less susceptible to disturbance-related and invasive herbs than clear-cuts: Temporal changes in the understorey after experimental silvicultural treatments

Forest management has a major impact on the understorey vegetation, with the intensity and type of the applied silvicultural treatments driving variable vegetation responses. We compared understorey variables across different experimental silvicultural treatments in a temperate oak-hornbeam forest in Central Hungary. Five treatment types were used in six replicates representing rotation and selection silvicultural systems: control (C), clear-cutting (CC), gap-cutting (G), preparation cutting (P), and retention tree group (R). The response of several understorey variables was investigated to the treatments in the first six years after their implementation in 2014.We assessed how understorey variables change in response to different forestry treatments, how these responses vary with time, and how game exclusion affects them. We then evaluated how well the treatments can preserve the forest character of the vegetation.We found a large temporal variability in the understorey variables over the study period. In all cases, the interventions led to an initial increase in species richness, followed by a decline later, where the regeneration layer started to close. The regeneration layer grew most intensively in G and CC. At the end of the study, R had the highest average species number, comprising a heterogeneous group of perennial forb species. The interventions all resulted in a rapid increase in total herb layer cover, mainly in favour of graminoid and perennial species. The extent of cover increase depended primarily on the amount of additional light received (CC > G > P > R > C). Turnover and beta diversity values also decreased in a similar order. The effect of game exclusion was especially pronounced in the case of the CC and G, where game browsing significantly slowed the regeneration outside the fences. The most significant changes in almost all variables were in the CC. It had the highest number of indicator species, many of them annual, disturbance-related, and invasive. G preserved the forest character of the vegetation better and proved to be less susceptible to the mass appearance of disturbance-related and invasive herbaceous species.Increasing the share of continuous cover forestry methods is crucial to preserve the forest herb layer. Rotation forestry with large cutting areas is not recommended or should be kept at low landscape rates, as these areas are highly exposed to disturbance-related and invasive species. Leaving retention tree groups can be key to the survival of numerous forest plant species.

Comparison of the Efficiency of Overcoming the Crisis of Russian and Foreign Oil and Gas Companies

The purpose of the study was to evaluate the performance of large domestic and foreign oil and gas companies based on a factor analysis of the return on equity in the context of financial and economic crises. The relevance of the topic is due, on the one hand, to the leading role of the oil and gas industry in the Russian economy, and, on the other hand, to the need develop modern tools for the assessment and prediction of the performance of companies and comparison of the results of economic activity with those of foreign competitors. The object of the study was the financial performance of the largest domestic and foreign vertically integrated oil and gas companies. The subject of the study is the methods of deterministic factor analysis for assessing indicators in the oil and gas sector. The paper analyzes the main empirical indicators that reflect the degree of efficiency, justifies the choice of the profitability indicator of own assets as the main indicator for research in the oil and gas industry, analyzes approaches to assessing the contribution of various factors to the final efficiency. Methods of classification, decomposition, statistical, comparative and factor analysis were used. A five-factor DuPont decomposition of the return on equity was carried out, and the key factors affecting the efficiency of companies were identified: tax burden coefficient, percentage burden coefficient, return on sales, asset turnover ratio, financial leverage ratio. Using the LMDI‑1 model, the impact of changes in economic factors on changes in the efficiency of companies in 2013–2017 and 2018–2021 was assessed. It was concluded that domestic companies, on average, slightly outperformed foreign ones in terms of the considered efficiency indicator and coped better with the consequences of financial and economic crises in the periods under review. At the same time, domestic companies have a higher value of the tax burden coefficient with lower values of assets turnover and financial leverage.

Efficiency Assessment between Entrapment and Covalent Bond Immobilization of Mutant β-Xylosidase onto Chitosan Support.

The Y509E mutant of β-xylosidase from Geobacillus stearothermophilus (XynB2Y509E) (which also bears xylanase activity) has been immobilized in chitosan spheres through either entrapment or covalent bond formation methods. The maximum immobilization yield by entrapment was achieved by chitosan beads developed using a 2% chitosan solution after 1 h of maturation time in CFG buffer with ethanol. On the other hand, the highest value in covalent bond immobilization was observed when employing chitosan beads that were prepared from a 2% chitosan solution after 4 h of activation in 1% glutaraldehyde solution at pH 8. The activity expressed after immobilization by covalent bonding was 23% higher compared to the activity expressed following entrapment immobilization, with values of 122.3 and 99.4 IU.g-1, respectively. Kinetic data revealed that catalytic turnover values were decreased as compared to a free counterpart. Both biocatalysts showed increased thermal and pH stability, along with an improved storage capacity, as they retained 88% and 40% of their activity after being stored at 4 °C for two months. Moreover, XynB2Y509E immobilized by covalent binding also exhibited outstanding reusability, retaining 92% of activity after 10 cycles of reuse. In conclusion, our results suggest that the covalent bond method appears to be the best choice for XynB2Y509E immobilization.

Biomass and Productivity of Thalassia testudinum in Estuaries of the Florida Panhandle

Thalassia testudinum often dominates seagrass meadows of the Florida panhandle but few measurements of productivity, biomass, density, turnover or leaf area index in this region have been made. We targeted 5 estuaries located at similar latitudes, 30⁰ ± 0.3⁰N: Big Lagoon, Santa Rosa Sound, St. Andrew Bay, St. Joseph Bay, and St. George Sound. This study was one component of a collaborative partnership of state and local researchers examining factors preventing recovery in panhandle estuarine areas that had historically contained seagrass in the 1940s and 1950s. Measurements were made twice in 2016, once in June and then again in summer or fall, except in Santa Rosa Sound where measurements were made 3 times. In the estuaries sampled for the second time in July or August, aboveground productivity was greater than in June. St. Joseph Bay had the highest aboveground productivity (4.3 g/m2/d) and 1—sided leaf area index (4.2) while St. George Sound had the lowest values (0.41 g/m2/d and 1.0). Principal component analysis suggested that St. Andrew Bay, Big Lagoon and Santa Rosa Sound were the most similar, with higher values for shoot densities and leaf turnover and lower salinities and watershed:water ratios. St. Joseph Bay had high aboveground productivity and salinity, and low turbidity. St. George Sound had low aboveground productivity, high total suspended solids and the highest watershed:water ratio. These baseline productivity estimates will be useful to assess the success of restoration efforts targeting seagrasses in the Florida panhandle and evaluate impacts of climate change on seagrasses.

Türkiye'nin Orta Karadeniz Bölgesi Ova Çayır Vejetasyonunda Hayvan Otlatılan Bir Alan ve Hayvan Otlatılmayan Korunmuş Bir Komşu Arazinin Yeraltı Biyokütlesi ve Verimliliği

The subject of this study is to determine the below-ground plant biomass and annual below-ground net primary production of lowland meadows in the Central Black Sea region. This study calculated the annual average amount of below-ground plant biomass, its seasonal distribution, annual primary production, and turnover values in the ungrazed and grazed meadow stands. Below-ground plant biomass, below-ground net primary production, and turnover of grazed stands were higher than in ungrazed stands. This turnover value shows that root biomass is renewed faster in grazed areas. Grazing, annual rainfall, and soil characteristics may have led to these different results.

Glacial biodiversity of the southernmost glaciers of the European Alps (Clapier and Peirabroc, Italy)

We applied a multi-taxa approach integrating the co-occurrence of plants, ground beetles, spiders and springtails with soil parameters (temperatures and chemical characteristics) in order to describe the primary succession along two glacier forelands in the Maritime Alps (Italy), a hotspot of Mediterranean biodiversity. We compared these successions to those from Central Alps: Maritime glacier forelands markedly differ for their higher values of species richness and species turnover. Contrary to our expectation, Maritime glacier forelands follow a ‘replacement change model’, like continental succession of Inner Alps and differently from other peripheral successions. We propose that the temperatures along these Mediterranean glacier forelands are warmer than those along other Alpine glacier forelands, which promote the faster species turnover. Furthermore, we found that early and mid successional stages of the investigated glaciers are richer in cold-adapted and endemic species than the later ones: we confirmed that the ‘replacement change’ model disadvantages pioneer, cold-adapted species. Given the overall correspondence among cold-adapted and endemic species, the most threatened in this climate phase, our results raise new concerns about the extinction risk of these species. We also describe supraglacial habitat of Maritime glaciers demonstrating that supraglacial debris represents an environment decoupled from the regional climate and may have an important role as refugium for coldadapted and hygrophilous plant and animal species, whose survival can be threatened by climate change and by a rapid ecological succession in the adjacent forelands.

Diversity of Lacewings (Neuroptera) in an Altitudinal Gradient of the Tacaná Volcano, Southern Mexico.

Simple SummaryLacewings are insects with a great diversity of morphology and habits and are potentially important as bioindicators and biological control agents. However, there is little worldwide information on their patterns of distribution and diversity. Therefore, it is essential to understand what changes occur in their diversity through spatial changes such as elevation. We analyzed Neuroptera diversity locally and between sites through an elevation gradient, finding two marked trends: (1) a decrease in richness with increasing altitude and, (2) greater diversity and potential richness at an intermediate elevation. In addition, a high degree of species turnover means that there is an evident transition between the lowland communities and the forest in the upper parts of the volcano, reflecting an altitudinal replacement of species and exclusivity for certain altitudes. These patterns will help us understand the distribution diversity of lacewings for better management and conservation of insects and the ecosystems with which they are associated.Neuroptera is an order of insects with a moderate diversity of species numbers yet a high between-family morphological diversity, which has a significant ecological role as a predator. However, there are few studies focused on describing changes in species diversity along environmental gradients. We evaluated changes in the alpha and beta diversity of species and the higher taxa in Neuroptera communities in the Tacaná Volcano in southern Mexico. Five sites each at different altitudes were studied through systematic annual sampling. The taxonomic and phylogenetic alpha diversity were analyzed, as well as the beta diversity and its components, species turnover and nestedness. The alpha diversity had two trends: (1) decreased standardized richness and taxonomic distinctness with increasing altitude, and (2) increased estimated richness and species diversity at intermediate altitudes. The highest turnover values for species, as well as for supra-specific taxa, were recorded at sites with lower altitudes. The highest total beta diversity value was recorded at elevations above 3000 m, whereas the highest number of species and supra-specific taxa were observed at sites between 600 and 2000 m, with an evident decrease above 3000 m. The type of vegetation and environmental conditions may be influencing the decrease in diversity toward higher elevations, which could explain the niche specialization of Neuroptera species to particular sites within the gradient. These results highlight the need to study the environmental factors and their effects on species composition along an elevation gradient.

Исследование риска выполнения планового показателя грузооборота железнодорожным транспортом в условиях развития пандемии

Objective: The risk assessment of fulfillment of planned cargo turnover indicators was carried out, the implementation of which required the following main stages of the study: modeling and verification of the model, model point and interval forecasting, forecast analysis and risk assessment. A mathematical model of the dependence of the turnover from year transportation of goods by rail is constructed for the sample statistics from Rosstat from 2009 to 2019. Verification was performed based on the results of cargo turnover in 2020. The construction of the model, verification and prediction were carried out using the Excel. Methods: The model is based on regression analysis and the method of least squares. Results: Comparison of forecast and planned values of cargo turnover showed that the plans for 2021–2023 are within the confidence interval and are feasible with varying degrees of risk, but have almost its maximum level, that is, they are achievable with a low level of probability. Practical importance: Plans for 2022 and 2023 need to be finalized taking into account the development of a pandemic in the country, and, therefore, require a possible reduction in their magnitude. It is advisable to regularly update forecast estimates according to the proposed methodology, taking into account the actual implementation of plans in 2021, taking into account the impact of measures taken in the country to combat the coronavirus pandemic on them.

Current Challenges for the Postal Services Sector in the Context of E-Commerce – Predictive Analysis of V4 States

The article’s focus is on the postal services sector. The sector plays an important role in a process of delivering packages to the customers. Over the last few years, there has been a significant growth in volume of shipments transported. The aim of the article is to demonstrate the current development and subsequent prediction of two selected indicators that play an important role in the context of e-commerce development in the V4 states. One of the indicators is the number of shipments; the other is the indicator of CO2 emissions. While the values of the CO2 emission in the predictive analysis in comparison with the growing e-commerce turnover indicator stagnate, the number of shipments is growing alongside the e-commerce turnover values. In the light of these findings, it is clear that the growing number of shipments will result in the need to change the approach to the organisation of the parcel delivery process, especially in big cities and agglomerations. It is also necessary to mention that organisational changes in the parcel delivery process in big cities and agglomerations must be carried out in an environmentally friendly way.

Partitioning and drivers of aquatic insect beta diversity in mountain streams

In recent years, interest in considering multiple facets of diversity has grown among community ecologists. Biological communities are complex systems, and exploring multiple facets can help reveal the main processes that drive diversity patterns. In this paper, we used a metacommunity framework to study the taxonomic, phylogenetic, and functional facets of beta diversity in assemblages of aquatic insects (Ephemeroptera and Trichoptera) with data from mountain streams collected in 2 study systems in the Mata Atlântica (Atlantic Forest) of Brazil: 22 streams from the northern coast of the São Paulo State and 33 streams from the southern coast of São Paulo State. We assessed the following: 1) the relative contributions of turnover and nestedness for different facets of beta diversity and 2) the relationships between environmental and spatial factors on the different facets and components of beta diversity. Beta diversities were high for all facets, and turnover was the main component of the taxonomic (based on incidence and abundance) and phylogenetic facets. In contrast, nestedness was an important component of the functional facet. The roles played by environmental and spatial variables varied erratically between the studied facets, insect orders, and study systems. Environment and space were both poor predictors of the different facets of beta diversity. Our results demonstrated that the difficulty of explaining the taxonomic beta diversity observed in other studies of aquatic insect stream metacommunities also arises for other facets of beta diversity (phylogenetic and functional). The high values of turnover found for most facets suggest that conservation strategies should seek to preserve as many streams as possible within a hydrographic network.

The Bone Microarchitecture Deficit in Patients with Hemophilia Is Influenced by Arthropathy, Hepatitis C Infection, and Physical Activity.

Low bone mineral density (BMD) is common in patients with hemophilia (PWHs). The aim of the present study was to describe BMD and microarchitecture in PWHs in Northern Germany and to determine factors contributing to possible skeletal alterations. Demographic characteristics, BMD and microarchitecture, bone metabolism markers, and orthopaedic joint score (OJS) were assessed during routine check-ups. Areal BMD was assessed by dual-energy X-ray absorptiometry (DXA) at the hip and lumbar spine. Volumetric BMD and microarchitecture were quantified by high-resolution peripheral quantitative computed tomography at the distal radius and tibia. Eighty male PWHs (median age, 33 years; range, 18-77) were retrospectively analyzed, of whom 67 (84.0%) and 13 (16.0%) had hemophilia A and B, respectively. Fifty-four (68.0%), six (7.0%), and 20 (25.0%) patients had severe, moderate, or mild hemophilia, and 35 (44.0%) were hepatitis C virus (HCV) positive. DXA analysis revealed low BMD (Z-score ≤ - 2.0) in 27.5% of PWHs, and higher bone turnover values were associated with lower BMD. Bone microarchitecture was dominated by cortical deficits at the radius and trabecular deficits at the tibia. Cortical deficits at the radius were influenced by lower body mass index, low-grade inflammation, and treatment regimen (higher cortical thickness on primary prophylaxis). Trabecular alterations at the tibia were mainly associated with OJS and HCV status. A positive effect of self-reported sportive activity on BMD could be shown. In conclusion, our findings demonstrate that the site-specific microarchitectural deficit observed in PWHs is primarily negatively influenced by poor joint status, inflammation, HCV infection, and high bone turnover.

Bone Histomorphometry and 18F-Sodium Fluoride Positron Emission Tomography Imaging: Comparison Between only Bone Turnover-based and Unified TMV-based Classification of Renal Osteodystrophy

Bone biopsy is the gold standard for characterization of renal osteodystrophy (ROD). However, the classification of the subtypes of ROD based on histomorphometric parameters is not unambiguous and the range of normal values for turnover differ in different publications. 18F-Sodium Fluoride positron emission tomography (18F-NaF PET) is a dynamic imaging technique that measures turnover. 18F-NaF PET has previously been shown to correlate with histomorphometric parameters. In this cross-sectional study, 26 patients on dialysis underwent a 18F-NaF PET and a bone biopsy. Bone turnover-based classification was assessed using Malluche’s historical reference values for normal bone turnover. In unified turnover-mineralization-volume (TMV)-based classification, the whole histopathological picture was evaluated and the range for normal turnover was set accordingly. Fluoride activity was measured in the lumbar spine (L1–L4) and at the anterior iliac crest. On the basis of turnover-based classification of ROD, 12% had high turnover and 61% had low turnover bone disease. On the basis of unified TMV-based classification of ROD, 42% had high turnover/hyperparathyroid bone disease and 23% had low turnover/adynamic bone disease. When using unified TMV-based classification of ROD, 18F-NaF PET had an AUC of 0.86 to discriminate hyperparathyroid bone disease from other types of ROD and an AUC of 0.87, for discriminating adynamic bone disease. There was a disproportion between turnover-based classification and unified TMV-based classification. More research is needed to establish normal range of bone turnover in patients with CKD and to establish the role of PET imaging in ROD.

COMPARATIVE FORECAST OF PASSENGER TRANSPORTATION IN LONG HAUL RAILWAY AND LONG-DISTANCE BUS SERVICE

The article presents methodological approaches to determining the volume of passenger service in long-distance railway connections and intercity bus services in Ukraine, which are expected in the coming years. Goal. The purpose of the study is to increase the reliability of the information base for making informed management decisions on the further development of the transport passenger complex. Methodology. In the process of research there was used a set of methods of expert assessment and logical analysis of possible factors influencing; economic and mathematical modeling; formalized extrapolation methods to determine the predictive parameters of influencing factors. Results. The forecast values of the number of transported passengers and the values of passenger turnover in long-distance railway and intercity bus connections in the short-term period are obtained. Originality. To estimate the forecast values of passenger traffic there was used the combination of methods of correlation-regression analysis and forecasting the magnitude of factors by the method of variable average. Practical value. The study of the patterns of passenger traffic dynamics revealed that in the next two years no significant changes are expected in the volume of work of both kinds of transport. However, in long-distance railway transport it is possible to increase passenger traffic by 1.6% (0.74 million passengers) and, accordingly, the annual passenger turnover will increase by 2.2%. In the intercity bus service, a slight decrease in the volume of passenger traffic by 0.8% (0.93 million passengers) is possible, and the rate of decrease in annual passenger turnover will be 0.5%. In the conditions of constant reduction of the population of Ukraine the most effective mechanism of ensuring further sustainable development of both types of passenger transportation is constant adjustment of tariff policy on the principles of flexibility and bonus tariff formation under condition of continuous improvement of services quality.

Portfolio Optimization Constrained by Performance Attribution

This paper investigates performance attribution measures as a basis for constraining portfolio optimization. We employ optimizations that minimize conditional value-at-risk and investigate two performance attributes, asset allocation (AA) and the selection effect (SE), as constraints on asset weights. The test portfolio consists of stocks from the Dow Jones Industrial Average index. Values for the performance attributes are established relative to two benchmarks, equi-weighted and price-weighted portfolios of the same stocks. Performance of the optimized portfolios is judged using comparisons of cumulative price and the risk-measures: maximum drawdown, Sharpe ratio, Sortino–Satchell ratio and Rachev ratio. The results suggest that achieving SE performance thresholds requires larger turnover values than that required for achieving comparable AA thresholds. The results also suggest a positive role in price and risk-measure performance for the imposition of constraints on AA and SE.

Taxonomic and phylogenetic beta diversity of cricetid rodents in Oaxaca, southern Mexico

AbstractUnderstanding the ecological and historical causes and processes that shape biodiversity distribution patterns remains a challenging and fundamental task in biogeography, ecology, and evolution. To address this issue, taxonomic and phylogenetic β diversity can help us to assess the importance of ecological and historical factors that structure these biotic patterns. To make inferences about the processes underlying current spatial patterns in communities of Cricetidae across the state of Oaxaca, Mexico, their taxonomic and phylogenetic β diversity were assessed jointly. Our aims were: 1) to examine taxonomic and phylogenetic β diversity and their turnover and nestedness components among physiographic subprovinces; 2) to test for statistical significance of observed phylogenetic β diversity against the expected values of a null model; and 3) to evaluate if these metrics were correlated with geographical distance. We obtained the species composition for 12 subprovinces based on distribution models for 49 cricetid species present in Oaxaca, then carried out a maximum likelihood analysis to estimate their phylogenetic relationships. Our results show that the taxonomic and phylogenetic dissimilarities mainly were explained by the turnover component of species and lineages. In almost all pairwise comparisons, the null model approach revealed random patterns for phylogenetic β diversity values and its components. Mantel correlation models showed that the values of total taxonomic and phylogenetic diversity and their components are correlated with the geographical distances between subprovinces. Our results suggest that both taxonomic and phylogenetic β diversity are explained by the interplay between biogeographical history from southern Mexico, and the recent speciation processes in cricetid rodents. Given that speciation processes are allopatric for most cricetid taxa, the high values of spatial turnover can be explained by the small ranges of species, coupled with current abiotic conditions that act as filters, promoting specialization of species on particular conditions. Our results show the importance of the phylogenetic approach to unravel the multidimensional spatial patterns of biodiversity.