Linear Connections on Normal Almost Contact Manifolds with Norden Metric

Families of linear connections are constructed on almost con- tact manifolds with Norden metric. An analogous connection to the symmetric Yano connection is obtained on a normal almost contact manifold with Norden metric and closed structural 1-form. The curvature properties of this connec- tion are studied on two basic classes of normal almost contact manifolds with Norden metric.

Natural Connections with Totally Skew-Symmetric Torsion on Manifolds with Norden-Type Metrics

This paper is a survey of results obtained by the authors on the geometry of connections with totally skew-symmetric torsion on the following manifolds: almost complex manifolds with Norden metric, almost contact manifolds with B-metric and almost hypercomplex manifolds with Hermitian and anti-Hermitian metric.

On Affine Connections in a Riemannian Manifold with a Circulant Metric and two Circulant Affinor Structures

Ива Р. Докузова, Димитър Р. Разпопов - В настоящата статия е разгледан клас V оттримерни риманови многообразия M с метрика g и два афинорни тензора q и S. Дефинирана е и друга метрика ¯g в M. Локалните координати на всички тези тензори са циркулантни матрици. Намерени са: 1) зависимост между тензора на кривина R породен от g и тензора на кривина ¯R породен от ¯g; 2) тъждество за тензора на кривина R в случая, когато тензорът на кривина ¯R се анулира; 3) зависимост между секционната кривина на прозволна двумерна q-площадка {x, qx} и скаларната кривина на M.

A finite element approach to modelling the hydrological regime in horizontal subsurface flow constructed wetlands for wastewater treatment

A Finite Element Analysis (FEA) model is used to explore the relationship between clogging and hydraulics that occurs in Horizontal Subsurface Flow Treatment Wetlands (HSSF TWs) in the United Kingdom (UK). Clogging is assumed to be caused by particle transport and an existing single collector efficiency model is implemented to describe this behaviour. The flow model was validated against HSSF TW survey results obtained from the literature. The model successfully simulated the influence of overland flow on hydrodynamics, and the interaction between vertical flow through the low permeability surface layer and the horizontal flow of the saturated water table. The clogging model described the development of clogging within the system but under-predicted the extent of clogging which occurred over 15 years. This is because important clogging mechanisms were not considered by the model, such as biomass growth and vegetation establishment. The model showed the usefulness of FEA for linking hydraulic and clogging phenomenon in HSSF TWs and could be extended to include treatment processes. © 2011 Springer Science+Business Media B.V.

On the role of surface roughness in the aerodynamic performance and energy conversion of horizontal wind turbine blades:a review

Summary: Renewable energy is one of the main pillars of sustainable development, especially in developing economies. Increasing energy demand and the limitation of fossil fuel reserves make the use of renewable energy essential for sustainable development. Wind energy is considered to be one of the most important resources of renewable energy. In North African countries, such as Egypt, wind energy has an enormous potential; however, it faces quite a number of technical challenges related to the performance of wind turbines in the Saharan environment. Seasonal sand storms affect the performance of wind turbines in many ways, one of which is increasing the wind turbine aerodynamic resistance through the increase of blade surface roughness. The power loss because of blade surface deterioration is significant in wind turbines. The surface roughness of wind turbine blades deteriorates because of several environmental conditions such as ice or sand. This paper is the first review on the topic of surface roughness effects on the performance of horizontal-axis wind turbines. The review covers the numerical simulation and experimental studies as well as discussing the present research trends to develop a roadmap for better understanding and improvement of wind turbine performance in deleterious environments.

Hajózni muszáj! - A GDP, az ökológiai lábnyom és a szubjektív jóllét stratégiai összefüggései ("Navigare necesse est." The connections between GDP, ecological footprint, and subjective welfare)

A tanulmányban országok környezetterhelését és jóllétét vizsgáljuk. A környezetterhelést vizsgáló klasszikus I = PAT azonosság célszerű átrendezésével és továbbgondolásával két térképet szerkesztünk, amelyek egy véges, korlátozott erőforrású világban segítik a stratégiai döntéshozatalt. A térképek adatait a bruttó hazai termék, az ökológiai lábnyom, illetve a szubjektív jóllét mutatói szolgáltatják, ezek az információk a világ országaira ma már széles körben rendelkezésre állnak. Bemutatjuk a gazdasági tevékenység és a szubjektív jóllét kapcsolatát, s az erre épülő 12 stratégiát, majd a szűkös természeti erőforrásokkal számot vető újabb 12 stratégialehetőséget tárgyaljuk. A gazdasági tevékenységet, a környezeti korlátokat és az emberi boldogságot egyszerre szem előtt tartó modell alapján nyilvánvaló a makroszintű következtetés: napjainkban a gazdasági tevékenység, illetve az emberi jóllét dematerializációja szükséges és kívánatos célkitűzés /===/ The study examines countries' ecological footprint and welfare. Rearranging and developing the classic I = PAT equation, the author has devised two maps to assist strategic decision-making in a world of finite, limited resources. The data on the maps – GDP, ecological footprint, and subjective welfare indices – are all widely available all over the world. The relation between economic activity and subjective welfare is presented and twelve strategies built upon them, before discussing twelve further strategies based on scarce natural resources. Using a model that considers economic activity, environmental constraints and human happiness concurrently, it becomes obvious that dematerialization of economic activity and human welfare are a necessary and desirable objective.

A horizontális és vertikális ágazaton belüli agrárkereskedelem meghatározó tényezői az EU új tagországaiban (Determinants of horizontal and vertical intra-industry agri-food trade in the new EU member-states)

Az ágazaton belüli kereskedelem egyre komolyabb szerepet tölt be a nemzetközi kereskedelemben, mind ez idáig azonban kevés mezőgazdasági témájú elemzés készült e témában. A cikk célja a horizontális és vertikális ágazaton belüli agrárkereskedelem meghatározó tényezőinek azonosítása az új tagországok és az EU–27 közötti kereskedelemben 1999–2010 között. Ehhez a szerző statikus és dinamikus panelmódszereket alkalmaz különböző specifikációkkal. Eredményei szerint a tényezőellátottság a horizontális ágazaton belüli kereskedelemmel negatív, míg a vertikálissal pozitív kapcsolatban áll. Az országok mérete az ágazaton belüli kereskedelem mindkét oldalával pozitívan, míg a távolság negatívan korrelál. Az eredmények azt is kimutatják, hogy az ágazaton belüli kereskedelem mértéke nagyobb, ha egy új tagország a kelet-közép-európai régióba exportál, és az is világossá vált, hogy az EU-csatlakozás pozitívan hatott az ágazaton belüli kereskedelemre, jelezve a gazdasági integráció kereskedelemösztönző szerepét. _____ Intra-industry trade (IIT) has a growing role in international trade, although the number of papers on its agricultural aspects is limited. This article identifies the determinants of horizontal and vertical intra-industry agri-food trade between new member-states (NMS) and the EU27 in 1999-2010, by applying to panel data static and dynamic models with different specifications. The results show that factor endowments are negatively related to agri-food horizontal intra-industry trade (HIIT), but positively to vertical intra-industry trade (VIIT). Economic size is positively and significantly related to both, while distance and IIT are found to be negatively related. This also suggests that HIIT and VIIT are greater if an NMS exports agri-food products to another NMS, while EU accession has had positive and significant impacts on both HIIT and VIIT, which suggests that economic integration fosters IIT.

Horizontal diversity of higher education institutions. The case of Hungary – in European context

In the European Higher Education Area the diversification of higher education is considered to be an emphasized value, a guarantee of creativity. The various institutional rankings are the displays of vertical diversity, but in parallel with these, there is an increasing attention directed at horizontal diversity, the entirety of the institutions' activities. The European Mapping Project (U-map) undertook this challenge. The paper presents the research program, which is an attempt to adapt the U-map model to Hungary. According to the results, the U-map method which was intended for application on an international level, is very useful in the identification of the main groups of institutions in a specific national higher education system as well, and may provide a basis for the creation of institutional strategies and the development of the institutions’ network.

Country-specific determinants of horizontal and vertical intra-industry agri-food trade: the case of Bulgaria and Romania

The article analyses patterns and country-specific determinants of agri-food trade of Bulgaria and Romania with the European Union. As literature focusing on agricultural aspects of the topic is limited, the paper seeks to contribute to the literature by providing up to date results and suggestions as well as by identifying the determinants of horizontal and vertical intra-industry trade of the Bulgaria and Romania after EU accession. Results suggest that intra-industry agri-food trade is mainly of vertical nature, referring to trade of different quality products. Results verify that determinants of horizontal and vertical IIT are similar and suggest that economic size and FDI are positively, while factor endowments and distance are negatively related to both sides of IIT. Results are mainly in line with the majority of empirical literature in the field.

Horizontal genetic transfer in asexual fungi

Four aspects of horizontal genetic transfer during heterokaryon formation were examined in the asexual pathogen Fusarium oxysporum f.sp. cubense (Foc): (1) variability based on method of heterokaryon formation; (2) differences in nuclear and mitochondrial inheritance; (3) the occurrence of recombination without nuclear fusion; (4) the occurrence of horizontal genetic transfer between distantly related isolates. The use of non-pathogenic strains of Fusarium oxysporum as biocontrol agents warrants a closer examination at the reproductive life cycle of this fungus, particularly if drug resistance or pathogenicity genes can be transmitted horizontally. Experiments were divided into three phases. Phase I looked at heterokaryon formation by hyphal anastomosis and protoplast fusion. Phase II was a time course of heterokaryon formation to look at patterns of nuclear and mitochondrial inheritance. Phase III examined the genetic relatedness of the different vegetative compatibility groups using a multilocus analysis approach. Heterokaryon formation was evident within and between vegetative compatibility groups. Observation of non-parental genotypes after heterokaryon formation confirmed that, although a rare event, horizontal genetic transfer occurred during heterokaryon formation. Uniparental mitochondria inheritance was observed in heterokaryons formed either by hyphal anastomosis or protoplast fusion. Drug resistance was expressed during heterokaryon formation, even across greater genetic distances than those distances imposed by vegetative compatibility. Phylogenies inferred from different molecular markers were incongruent at a significant level, challenging the clonal origins of Foc. Mating type genes were identified in this asexual pathogen Polymorphisms were detected within a Vegetative Compatibility Group (VCG) suggesting non-clonal inheritance and/or sexual recombination in Foc. This research was funded in part by a NIH-NIGMS (National Institutes of Health-National Institute of General Medical Sciences) Grant through the MBRS (Minority Biomedical Research Support), the Department of Biological Sciences and the Tropical Biology Program at FIU. ^

Aerodynamic load characteristics evaluation and tri-axial performance testing on fiber reinforced polymer connections and metal fasteners to promote hurricane damage mitigation

Damages during extreme wind events highlight the weaknesses of mechanical fasteners at the roof-to-wall connections in residential timber frame buildings. The allowable capacity of the metal fasteners is based on results of unidirectional component testing that do not simulate realistic tri-axial aerodynamic loading effects. The first objective of this research was to simulate hurricane effects and study hurricane-structure interaction at full-scale, facilitating better understanding of the combined impacts of wind, rain, and debris on inter-component connections at spatial and temporal scales. The second objective was to evaluate the performance of a non-intrusive roof-to-wall connection system using fiber reinforced polymer (FRP) materials and compare its load capacity to the capacity of an existing metal fastener under simulated aerodynamic loads. ^ The Wall of Wind (WoW) testing performed using FRP connections on a one-story gable-roof timber structure instrumented with a variety of sensors, was used to create a database on aerodynamic and aero-hydrodynamic loading on roof-to-wall connections tested under several parameters: angles of attack, wind-turbulence content, internal pressure conditions, with and without effects of rain. Based on the aerodynamic loading results obtained from WoW tests, sets of three force components (tri-axial mean loads) were combined into a series of resultant mean forces, which were used to test the FRP and metal connections in the structures laboratory up to failure. A new component testing system and test protocol were developed for testing fasteners under simulated triaxial loading as opposed to uni-axial loading. The tri-axial and uni-axial test results were compared for hurricane clips. Also, comparison was made between tri-axial load capacity of FRP and metal connections. ^ The research findings demonstrate that the FRP connection is a viable option for use in timber roof-to-wall connection system. Findings also confirm that current testing methods of mechanical fasteners tend to overestimate the actual load capacities of a connector. Additionally, the research also contributes to the development a new testing protocol for fasteners using tri-axial simultaneous loads based on the aerodynamic database obtained from the WoW testing. ^

Illustrating Cognitive Connections between Math and Language in Pre-Service Teachers’ Perceptions of Common or Everyday Terms

This paper introduces a new construct that we term Math Mediated Language (MML) focusing on the notion that common or everyday terms with mathematical meanings are important building blocks for students’ mathematical reasoning. A survey given to 96 pre-service early childhood educators indicated clear patterns of perceptions of these terms.

Determination of vertical and horizontal pathways of injected fresh wastewater into a deep saline aquifer (Florida, USA) using natural chemical tracers

Two deep-well injection sites in south Florida, USA, inject an average of 430 million liters per day (MLD) of treated domestic fresh wastewater into a deep saline aquifer 900 m below land surface. Elevated levels of NH3 (highest concentration 939 µmol) in the overlying aquifer above ambient concentrations (concentration less than 30 µmol) were evidence of the upward migration of injected fluids. Three pathways were distinguished based on ammonium, chloride and bromide ratios, and temperature. At the South District Wastewater Treatment Plant, the tracer ratios showed that the injectate remained chemically distinct as it migrated upwards through rapid vertical pathways via density-driven buoyancy. The warmer injectate (mean 28°C) retained the temperature signal as it vertically migrated upwards; however, the temperature signal did not persist as the injectate moved horizontally into the overlying aquifers. Once introduced, the injectate moved slowly horizontally through the aquifer and mixed with ambient water. At the North District Wastewater Treatment Plant, data provide strong evidence of a one-time pulse of injectate into the overlying aquifers due to improper well construction. No evidence of rapid vertical pathways was observed at the North District Wastewater Treatment Plant.

An analytical investigation into shear wall and slab interconnections between reinforced concrete modules for high -rise buildings utilising modular construction under extreme seismic and wind loading

This research investigates a new structural system utilising modular construction. Five-sided boxes are cast on-site and stacked together to form a building. An analytical model was created of a typical building in each of two different analysis programs utilising the finite element method (Robot Millennium and ETABS). The pros and cons of both Robot Millennium and ETABS are listed at several key stages in the development of an analytical model utilising this structural system. Robot Millennium was initially utilised but created an analytical model too large to be successfully run. The computation requirements were too large for conventional computers. Therefore Robot Millennium was abandoned in favour of ETABS, whose more simplistic algorithms and assumptions permitted running this large computation model. Tips are provided as well as pitfalls signalled throughout the process of modelling such complex buildings of this type. ^ The building under high seismic loading required a new horizontal shear mechanism. This dissertation has proposed to create a secondary floor that ties to the modular box through the use of gunwales, and roughened surfaces with epoxy coatings. In addition, vertical connections necessitated a new type of shear wall. These shear walls consisted of waffled external walls tied through both reinforcement and a secondary concrete pour. ^ This structural system has generated a new building which was found to be very rigid compared to a conventional structure. The proposed modular building exhibited a period of 1.27 seconds, which is about one-fifth of a conventional building. The maximum lateral drift occurs under seismic loading with a magnitude of 6.14 inches which is one-quarter of a conventional building's drift. The deflected shape and pattern of the interstorey drifts are consistent with those of a coupled shear wall building. In conclusion, the computer analysis indicate that this new structure exceeds current code requirements for both hurricane winds and high seismic loads, and concomitantly provides a shortened construction time with reduced funding. ^

A Tale of Two Fishes: Using Recreational Angler Records to Examine the Link Between Fish Catches and Floodplain Connections in a Subtropical Coastal River

In the tropical and subtropical wet and dry regions, maintaining natural hydrologic connections between coastal rivers and adjacent ephemeral wetlands is critical to conserving and sustaining high levels of fisheries production within these systems. Though there is a consensus that there is a need to maintain these natural connections, little is known about what attributes of floodplain inundation regimes are most important in sustaining fisheries production. Two attributes of the flood season and thus floodplain inundation that may be particularly influential to fisheries are the amplitude of the flood season (floodplain water depth and spatial extent of inundation) and the duration of the flood season (i.e., time floodplains are inundated). In mangrove-dominated Everglades coastal rivers, seasonal inundation of upstream marsh floodplains may play an important role in provisioning recreational fisheries; however, this relationship remains unknown. Using two Everglades coastal river fisheries as a model, we tested whether the amplitude of the flood season or the duration of the flood season is more important in explaining variation in angler catch records of common snook and largemouth bass collected from 1992 to 2012. We validated angler catches with fisheries-independent electrofishing conducted in the same region from 2004 to 2012. Our results showed (1) that bass angler catches tracked electrofishing catches, while snook catches were completely mismatched. And (2) that previous year's marsh dynamics, particularly the duration of the flood season, was more influential than the flood season amplitude in explaining variation in bass catches, such that bass angler catches were negatively correlated to the period time that floodplains remained disconnected from coastal rivers in the previous year, while snook catches were not very well explained by floodplain inundation terms.