bluuebunny/crossref_metadata_2025 huggingface dataset:
Efficient Numerical Solution of the Multi-Term Time Fractional Diffusion-Wave Equation
Authors: Ren Jincheng , Sun Zhi-Zhong
Published: March 2015

Some efficient numerical schemes are proposed to solve one-dimensional and two-dimensional multi-term time fractional diffusion-wave equation, by combining the compact difference approach for the spatial discretisation and an L1 approximation for the multi-term time Caputo fractional derivatives. The unconditional stability and global convergence of these schemes are proved rigorously, and several applications testify to their efficiency and confirm the orders of convergence.
Projection and Contraction Method for the Valuation of American Options
Authors: Song Haiming , Zhang Ran
Published: March 2015

An efficient numerical method is proposed for the valuation of American options via the Black-Scholes variational inequality. A far field boundary condition is employed to truncate the unbounded domain problem to produce the bounded domain problem with the associated variational inequality, to which our finite element method is applied. We prove that the matrix involved in the finite element method is symmetric and positive definite, and solve the discretized variational inequality by the projection and contraction method. Numerical experiments are conducted that demonstrate the superior performance of our method, in comparison with earlier methods.
О вычислении волноводной матрицы рассеяния для системы Максвелла
Authors: Plamenevskii Boris Alekseevich , Poretskii Aleksandr S , Sarafanov O V
Published: March 2015

Рассматривается система Максвелла в волноводе с идеально проводящей границей; волновод имеет несколько цилиндрических выходов на бесконечность. В качестве приближения для строки матрицы рассеяния предлагается минимизатор некоторого квадратичного функционала. Функционал строится посредством решения вспомогательной краевой задачи в ограниченной области, полученной отрезанием на расстоянии $R$ выходов волновода на бесконечность. Доказывается, что минимизатор $a(R, k)$ при $R \to \infty$ стремится с экспоненциальной скоростью к соответствующей строке матрицы рассеяния.
Степенная асимптотика спектральных функций граничных задач для обобщенных дифференциальных уравнений второго порядка с граничными условиями на сингулярном конце
Authors: Kats Izrail' Samoilovich
Published: March 2015

Пусть $I=(-\infty,b)$, где $b\le +\infty$. Пусть $M(x)$, $x\in I$, - вещественная неубывающая на $I$ функция и $M(x)>0$ при $x\in I$. В средине прошлого века было установлено, что в случае, когда $M(x)$ суммируема по Лебегу на интервале $(-\infty, c)$, $c\in I$, граничная задача
$-\frac{d}{dM(x)} y^+ (x)=\lambda y(x)$, $x\in I$, $\lim_{x\to -\infty}y(x)=1$ имеет при любом комплексном $\lambda$ единственное решение и хотя бы одну спектральную функцию $\tau (\lambda)$ ("$ ^+$" символ правой производной).
В заметке анонсируется результат, связывающий асимптотическое поведение $M(x)$ при $x \to -\infty$ c асимптотическим поведением $\tau(\lambda)$ при $\lambda \to +\infty$. Аналогичные результаты анонсируется также для двух других граничных задач с граничными условиями на сингулярном конце.
О множестве решений одного класса уравнений с cюръективными операторами
Authors: Gel'man Boris Danilovich
Published: March 2015

В заметке изучаются операторные уравнения вида $A(x)=f(x)$ в случае, когда $A$ является замкнутым линейным сюръективным оператором, а отображение $f$ является уплотняющим относительно оператора $A$. В ней не только доказываются теоремы существования, но и дается оценка топологической размерности множества решений этого уравнения. В заключение статьи полученные теоремы применяются для изучения множества глобальных решений одного класса уравнений нейтрального типа.
Craft Guilds and the Sustenance of Pre-Colonial Benin Monarchy
Authors: Osagie JI , Ikponmwosa F
Published: March 2015

Benin was one of the major kingdoms that thrived in the forest region of West Africa from about c.900 to1897 when she was conquered by the British expeditionary forces and integrated into the Protectorate of Southern Nigeria. The resilience and sustenance of the kingdom and her monarchy for this long period has been attributed to several factors such as the successive line of capable and effective Oba (kings) and her trade with the Europeans – Portuguese, Dutch and British – which enabled her to acquire arms and ammunitions for the defense and expansion of her territories. However, the vital role played by the craft guilds in the sustenance of the monarchy had not been given proper attention. The guilds which were associations of professional or craftsmen were involved in the production of variety of products and other items of utilities. It was in order to maximize the benefit derivable from their products the various Oba ensured that the craftsmen were organized into associations to supply every need of the monarch and the palace. It was in this respect that the various guilds in Benin were affiliated into the three main palace societies – Iwebo, Iweguae and Ibiwe. These societies were responsible for every facet of the needs of the palace. As the basic need of the monarchy was adequately met by the various guilds, the Oba had enough time and resources to devote to the effective administration of the kingdom. It is in this regards that this papers posits that the guilds played vital roles in the sustenance of Benin monarchy throughout the pre-colonial period.Key words: Guild System, Benin Kingdom, Palace Societies, Oba of Benin
“Omu Ngwo” (Omu-Furled - Tender Palm Frond) Symbology in Ikwerre, Rivers State
Authors: Olumati R
Published: March 2015

The furled young leaves of the palm tree are known as omu in Ikwerre language. It is an important motif among the Ikwerre. Ordinarily it has nothing of’ awe or fear attached to it. But when symbolically used as a communication medium, it attracts all the sacredness and fear that accompany sacred items. The use of omu as a sacred symbol among the Ikwerre is universal. The significance of omu has defied rejection by both modernity and Christianity. It is always laden with spiritual messages when put into use. Omu occupies very important position in the Ikwerre religious and social spheres. As one walks along the public and private roads, the sight of omu symbolically used is a common feature. Wherever omu is exhibited in its symbolic use, the observer immediately decodes the information and then appreciates the metaphysical richness of Ikwerre society. This study which took us to many places endowed us with the knowledge of how diversified the uses of omu are. This symbolic form is involved in maintaining the Ikwerre religious and social ethos, hence this paper. The focus of this paper therefore, is among the Ikwerre in Rivers State of the North Eastern Niger Delta Region.Key words: Tender, Palm Frond, Symbology, Sacred, Ikwerre
An Assessment of Nigeria-China Economic Relations from 1999-2014
Authors: Rindap MR
Published: March 2015

Nigeria and China established diplomatic relations in February 1971, relations between these two countries had blossomed over the years. This was made possible with the high level of visits and the conclusion of a number of bilateral agreements between the two countries. The bilateral relations progressed from political engagements to intense economic penetration of the Nigerian economy. China seemed to be driving the relations because there had been the issue of excessive trade imbalance in favour of China, poor infrastructural development of facilities in Nigeria which have hampered it from competing favourably with China. This paper looked at the historical overview of these relations, assessed the impact of the Chinese penetration of the Nigerian economy and the challenges faced by both countries in the pursuit of these economic relations. Finally, it provided ways of enhancing the relations between the two countries.
Aspect of Intergroup Relations in 21st Century Nigeria: Emblem of Ethnicity, Religious Fundamentalism and National Security Crisis 2000-2014
Authors: Egbefo DO
Published: March 2015

This paper is on the aspects of intergroup relations in 21st century Nigeria: Emblem of Ethnicity, Religious Fundamentalism and National Security Crisis, 2000-2014. The objective of the paper is to contribute to some existing literature on the state of intergroup relations in Nigeria. Besides, it would provoke further researchers on the subject because the Nigeria state is presently experiencing disintegrating challenges. It is already known by scholars that some contending issues and challenges have not encouraged intergroup relations in 21st century Nigeria but without their examining that of ethnicity, religious fundamentalism and national security threats as addressed in this paper using the available primary and secondary sources discussed in subthemes narration common to histories. With the triumphant entry of democratic rule and its gradual consolidation in this century Nigerians approached this development within a renewal of hope that inter-group contacts of the divergent ethnic nationalities started in the pre-colonial period would be consolidated before now. But the nation-state is yet trapped in woes of ethnicity, religious extremism and national security crisis thereby, aiding the reasons why meaningful inter-ethnic/group relations are eluding Nigeria.Key words: Intergroup Relations, 21st Century, Ethnicity, Religious Fundamentalism, National Security, Crisis
Assessing Organizational Capability of a Voluntary Organization that Provides Capacity Building Interventions to Socioeconomic Problem: Developing Country Context
Authors: Sanni GA
Published: March 2015

Many organizations are now involved in community capacity building-CCB through a voluntary organization (NGO) in order to empower their respective host communities and to complement government’s efforts in dealing with specific socioeconomic problem facing them. These organizations attached their involvement in CCB as part of their corporate social responsibility-CSR contributions to the society. These NGOs serve as capacity building providers. The major concern is that these NGOs do not have a framework in place to assess their own organizational capability in relations to the capacity building interventions-CBIs provided to the community for dealing with their respective problems. Many studies carried out on organizational capability focused on profit-making organizations and were not meant for voluntary organizations, because most of these studies view organizational capability from competitive advantage position. This paper intends to fill a gap by contributing to the development of theory on the assessment of organizational capability of a voluntary organization from a developing country context. This paper developed organizational capability assessment framework that can be used as a benchmark by any capacity building providers through modification of Hawe, et al.’s (1997) model on capacity building. The assessment index and their respective indicators were thoroughly examined in this paper.Key words: community capacity building, capacity building providers, organizational capability, capacity building interventions, voluntary organizations
Impact of Saccharomyces cerevisiae supplementation on reproductive performance, milk yield in ewes and offspring growth
Authors: Zaleska B. , Milewski S. , Ząbek K.
Published: March 2015

Abstract. The effect of supplementing sheep diets with Saccharomyces cerevisiae Inter Yeast® dried brewer's yeast (Leiber GmbH, Bramsche, Germany) or with a Biolex® Beta-S (Leiber GmbH, Bramsche, Germany) extract containing over 70 % β-1,3/1,6-D-glucan was investigated. Experiment 1 was carried out with 120 ewes and 190 lambs. The animals were divided into three groups: I – control; II – fed yeast; and III – fed Biolex. The supplements were administered during a 3-week preparation period for tupping and a 70-day lamb-rearing period. The following reproductive parameters were analysed: fertility, prolificacy, lamb rearing and breeding performance, milk yield and lamb growth rate. Experiment 2 was conducted with 120 ewes divided into two groups: I – control and II – fed yeast during a 3-week preparation period. Fertility and prolificacy were analysed. Significant increases in prolificacy were recorded in sheep administered dried brewer's yeast: 28.51 % in experiment 1 and 31.33 % in experiment 2. Breeding performance was also higher by 35 %. Both yeast supplements had a stimulating impact on the milk yield of ewes and the growth rate of their offspring. Milk from the experimental ewes, especially in the group fed Biolex, had a substantially higher content of dry matter, mainly fat. The lambs in this group had the highest body weight at the age of 70 days. Finally, however, the production of livestock per mother was highest in the group fed the supplement with Saccharomyces cerevisiae.
Seasonal trends in concentrations and fluxes of volatile organic compounds above central London
Authors: Valach A. C. , Langford B. , Nemitz E. , MacKenzie A. R. , Hewitt C. N.
Published: March 2015

Abstract. Concentrations and fluxes of seven volatile organic compounds (VOCs) were measured between August and December 2012 at a roof-top site in central London as part of the ClearfLo project (Clean Air for London). VOC concentrations were quantified using a proton transfer reaction-mass spectrometer and fluxes were calculated using a virtual disjunct eddy covariance technique. The median VOC fluxes, including aromatics, oxygenated compounds and isoprene, ranged from 0.07 to 0.33 mg m−2 h−1 and mixing ratios were 7.27 ppb for methanol (m / z 33) and <1 ppb for the remaining compounds. Strong relationships were observed between most VOC fluxes and concentrations with traffic density, but also with photosynthetically active radiation (PAR) and temperature for the oxygenated compounds and isoprene. An estimated 50–90 % of aromatic fluxes were attributable to traffic activity, which showed little seasonal variation, suggesting boundary layer effects or possibly advected pollution may be the primary causes of increased concentrations of aromatics in winter. PAR and temperature-dependent processes accounted for the majority of isoprene, methanol and acetaldehyde fluxes and concentrations in August and September, when fluxes and concentrations were largest. Modelled biogenic isoprene fluxes using the G95 algorithm agreed well with measured fluxes in August and September, due to urban vegetation. Comparisons of estimated annual benzene emissions from the London and National Atmospheric Emissions Inventory agreed well with measured benzene fluxes. Flux footprint analysis indicated emission sources were localized and that boundary layer dynamics and source strengths were responsible for temporal and spatial VOC flux and concentration variability during the measurement period.
Fire emission heights in the climate system – Part 1: Global plume height patterns simulated by ECHAM6-HAM2
Authors: Veira A. , Kloster S. , Wilkenskjeld S. , Remy S.
Published: March 2015

Abstract. We use the global circulation model ECHAM6 extended by the aerosol module HAM2 to simulate global patterns in wildfire emission heights. Prescribed plume heights in ECHAM6 are replaced by an implementation of a simple, semi-empirical plume height parametrization. In a first step, the global performance of the plume height parametrization is evaluated for plumes reported in the MISR Plume Height Project data set. Our results show that the parametrization simulates a largely reasonable global distribution of plume heights. While the modeled global mean plume height (1411±646 m) is in good agreement with the observed mean (1382±702 m), the upper and lower tails of the plume height distribution tend to be slightly underrepresented. Furthermore, we compare plume heights simulated by the simple parametrization to a more complex, analytical plume model. Major differences in global plume height distributions are found for the lowest 1.5 km, but reasonable agreement is observed for higher plumes. In a second step, Fire Radiative Power (FRP) as reported in the Global Fire Assimilation System (GFAS) is used to simulate plume heights for observed fires globally for the period 2005–2011. The global fraction of simulated daytime plumes injecting emissions into the free troposphere ranges from 3.7±0.7 to 5.2±1.0%. This range is comparable to results from observational studies, but it is much lower than for prescribed plume heights in the ECHAM6-HAM2 standard setup. Nevertheless, occasionally deep emission injections exceeding 5–7 km of height are simulated for intense fires and favorable meteorological conditions. The application of a prescribed diurnal cycle in FRP turns out to be of minor importance. For a hypothetical doubling in FRP, moderate changes in plume heights of 100–400 m are simulated. These small changes indicate that a potential future increase in fire intensity will only slightly impact the emission heights on global scale.
Fire emission heights in the climate system – Part 2: Impact on transport, Black Carbon concentrations and radiation
Authors: Veira A. , Kloster S. , Schutgens N. A. J. , Kaiser J. W.
Published: March 2015

Abstract. Wildfires represent a major source for aerosols impacting atmospheric radiation, atmospheric chemistry and cloud micro-physical properties. Although former studies indicated that the height of the aerosol–radiation interaction crucially affects the overall climate impact, the importance of fire emission heights in particular remains to be quantified. In this study we use the general circulation model ECHAM6 extended by the aerosol module HAM2 to investigate the impact of wildfire emission heights on atmospheric long-range transport, Black Carbon (BC) concentrations and atmospheric radiation. We simulate the wildfire aerosol release using either various versions of a semi-empirical plume height parametrization or prescribed standard emission heights in ECHAM6-HAM2. Extreme scenarios of near-surface or free-tropospheric only injections provide lower and upper constraints on the emission height climate impact. We find relative changes in mean global atmospheric BC burden of up to 7.9±4.4% caused by average changes in emission heights of 1.5–3.5 km. Regionally, changes in BC burden exceed 30–40% in the major biomass burning regions. The model evaluation of Aerosol Optical Thickness (AOT) against MODIS, AERONET and CALIOP observations indicates that the implementation of a plume height parametrization slightly reduces the ECHAM6-HAM2 biases regionally, but on the global scale these improvements in model performance are small. For prescribed emission release at the surface, wildfire emissions entail a total sky Top Of Atmosphere (TOA) Radiative Forcing (RF) of −0.16±0.06 W m−2. The application of a plume height parametrization which agrees reasonably well with observations introduces a slightly stronger negative TOA RF of −0.20±0.07 W m−2. The standard ECHAM6-HAM2 model in which 25% of the wildfire emissions are injected into the free troposphere and 75% into the planetary boundary layer, leads to a TOA RF of −0.24±0.06 W m−2. Overall, we conclude that simple plume height parametrizations provide sufficient representations of emission heights for global climate modeling. Significant improvements in aerosol wildfire modeling likely depend on better emission inventories and aerosol process modeling rather than on improved emission height parametrizations.
Quality control of 10-min soil temperatures data at RMI
Authors: Bertrand C. , González Sotelino L. , Journée M.
Published: March 2015

Abstract. Soil temperatures at various depths are unique parameters useful to describe both the surface energy processes and regional environmental and climate conditions. To provide soil temperature observation in different regions across Belgium for agricultural management as well as for climate research, soil temperatures are recorded in 13 of the 20 automated weather stations operated by the Royal Meteorological Institute (RMI) of Belgium. At each station, soil temperature can be measured at up to 5 different depths (from 5 to 100 cm) in addition to the bare soil and grass temperature records. Although many methods have been developed to identify erroneous air temperatures, little attention has been paid to quality control of soil temperature data. This contribution describes the newly developed semi-automatic quality control of 10-min soil temperatures data at RMI.
Seagrass meadows as a globally significant carbonate reservoir
Authors: Mazarrasa I. , Marbà N. , Lovelock C. E. , Serrano O. , Lavery P. S. , Fourqurean J. W. , Kennedy H. , Mateo M. A. , Krause-Jensen D. , Steven A. D. L. , Duarte C. M.
Published: March 2015

Abstract. There has been a growing interest in quantifying the capacity of seagrass ecosystems to act as carbon sinks as a natural way of offsetting anthropogenic carbon emissions to the atmosphere. However, most of the efforts have focused on the organic carbon (POC) stocks and accumulation rates and ignored the inorganic carbon (PIC) fraction, despite important carbonate pools associated with calcifying organisms inhabiting the meadows, such as epiphytes and benthic invertebrates, and despite the relevance that carbonate precipitation and dissolution processes have in the global carbon cycle. This study offers the first assessment of the global PIC stocks in seagrass sediments using a synthesis of published and unpublished data on sediment carbonate concentration from 402 vegetated and 34 adjacent un-vegetated sites. PIC stocks in the top 1 m sediments ranged between 3 and 1660 Mg PIC ha-1, with an average of 654 ± 24 Mg PIC ha-1, exceeding about 5 fold those of POC reported in previous studies. Sedimentary carbonate stocks varied across seagrass communities, with meadows dominated by Halodule, Thalassia or Cymodocea supporting the highest PIC stocks, and tended to decrease polewards at a rate of -8 ± 2 Mg PIC ha-1 degree-1 of latitude (GLM, p < 0.0003). Using PIC concentration and estimates of sediment accretion in seagrass meadows, mean PIC accumulation rates in seagrass sediments is 126.3 ± 0.7 g PIC m-2 y-1. Based on the global extent of seagrass meadows (177 000 to 600 000 km2), these ecosystems globally store between 11 and 39 Pg of PIC in the top meter of sediment and accumulate between 22 and 76 Tg PIC y-1, representing a significant contribution to the carbonate dynamics of coastal areas. Despite that these high rates of carbonate accumulation imply CO2 emissions from precipitation, seagrass meadows are still strong CO2 sinks as demonstrates the comparison of carbon (POC and POC) stocks between vegetated and adjacent un-vegetated sediments.
A non-equilibrium model for soil heating and moisture transport during extreme surface heating
Authors: Massman W. J.
Published: March 2015

Abstract. With increasing use of prescribed fire by land managers and increasing likelihood of wildfires due to climate change comes the need to improve modeling capability of extreme heating of soils during fires. This issue is addressed here by developing a one-dimensional non-equilibrium model of soil evaporation and transport of heat, soil moisture, and water vapor, for use with surface forcing ranging from daily solar cycles to extreme conditions encountered during fires. The model employs a linearized Crank–Nicolson scheme for the conservation equations of energy and mass and its performance is evaluated against dynamic soil temperature and moisture observations obtained during laboratory experiments on soil samples exposed to surface heat fluxes ranging between 10 000 and 50 000 W m−2. The Hertz–Knudsen equation is the basis for constructing the model's non-equilibrium evaporative source term. The model includes a dynamic residual soil moisture as a function of temperature and soil water potential, which allows the model to capture some of the dynamic aspects of the strongly bound soil moisture that seems to require temperatures well beyond 150 °C to fully evaporate. Furthermore, the model emulates the observed increase in soil moisture ahead of the drying front and the hiatus in the soil temperature rise during the strongly evaporative stage of drying. It also captures the observed rapid evaporation of soil moisture that occurs at relatively low temperatures (50–90 °C). Sensitivity analyses indicate that the model's success results primarily from the use of a temperature and moisture potential dependent condensation coefficient in the evaporative source term. The model's solution for water vapor density (and vapor pressure), which can exceed one standard atmosphere, cannot be experimentally verified, but they are supported by results from (earlier and very different) models developed for somewhat different purposes and for different porous media. Overall, this non-equilibrium model provides a much more physically realistic simulation over a previous equilibrium model developed for the same purpose. Current model performance strongly suggests that it is now ready for testing under field conditions.
Modeling suspended sediment sources and transport in the Ishikari River basin, Japan, using SPARROW
Authors: Duan W. L. , He B. , Takara K. , Luo P. P. , Nover D. , Hu M. C.
Published: March 2015

Abstract. It is important to understand the mechanisms that control the fate and transport of suspended sediment (SS) in rivers, because high suspended sediment loads have significant impacts on riverine hydroecology. In this study, the SPARROW (SPAtially Referenced Regression on Watershed Attributes) watershed model was applied to estimate the sources and transport of SS in surface waters of the Ishikari River basin (14 330 km2), the largest watershed in Hokkaido, Japan. The final developed SPARROW model has four source variables (developing lands, forest lands, agricultural lands, and stream channels), three landscape delivery variables (slope, soil permeability, and precipitation), two in-stream loss coefficients, including small streams (streams with drainage area < 200 km2) and large streams, and reservoir attenuation. The model was calibrated using measurements of SS from 31 monitoring sites of mixed spatial data on topography, soils and stream hydrography. Calibration results explain approximately 96% (R2) of the spatial variability in the natural logarithm mean annual SS flux (kg yr−1) and display relatively small prediction errors at the 31 monitoring stations. Results show that developing land is associated with the largest sediment yield at around 1006 kg km−2 yr−1, followed by agricultural land (234 kg km−2 yr−1). Estimation of incremental yields shows that 35% comes from agricultural lands, 23% from forested lands, 23% from developing lands, and 19% from stream channels. The results of this study improve our understanding of sediment production and transportation in the Ishikari River basin in general, which will benefit both the scientific and management communities in safeguarding water resources.
Calibration of FARSITE simulator in northern Iranian forests
Authors: Jahdi R. , Salis M. , Darvishsefat A. A. , Mostafavi M. A. , Alcasena F. , Etemad V. , Lozano O. , Spano D.
Published: March 2015

Abstract. Wildfire simulators based on empirical or physical models need to be locally calibrated and validated when used under conditions that differ from those where the simulators were originally developed. This study aims to calibrate the FARSITE fire spread model considering a set of recent wildfires that occurred in northern Iranian forests. Site-specific fuel models in the study areas were selected by sampling the main natural vegetation type complexes and assigning standard fuel models. Overall, simulated fires presented reliable outputs that accurately replicated the observed fire perimeters and behavior. Standard fuel models of Scott and Burgan (2005) afforded better accuracy in the simulated fire perimeters than the standard fuel models of Anderson (1982). The best match between observed and modeled burned areas was observed on herbaceous fuel models. Fire modeling showed a high potential for estimating spatial variability in fire spread and behavior in the study areas. This work represents a first step in the application of fire spread modeling in northern Iran for wildfire risk monitoring and management.
Time-dependent Long's equation
Authors: Humi M.
Published: March 2015

Abstract. Long's equation describes steady-state two-dimensional stratified flow over terrain. Its numerical solutions under various approximations were investigated by many authors. Special attention was paid to the properties of the gravity waves that are predicted to be generated as a result. In this paper we derive a time-dependent generalization of this equation and investigate analytically its solutions under some simplifications. These results might be useful in the experimental analysis of gravity waves over topography and their impact on atmospheric modeling.
Comparison of wheat and safflower cultivation areas in terms of total carbon and some soil properties under semi-arid climate conditions
Authors: Turgut B.
Published: March 2015

Abstract. The aim of this study was to compare the soils of the wheat cultivation area (WCA) and the safflower cultivation area (SCA) within semi-arid climate zones in terms of their total carbon, nitrogen, sulphur contents, particle size distribution, aggregate stability, organic matter content, and pH values. This study presents the results from the analyses of 140 soil samples taken at two soil layers (0–10 and 10–20 cm) in the cultivation areas. At the end of the study, it has been established that there were significant differences between the cultivation areas in terms of soil physical properties such as total carbon (TC), total nitrogen (TN), total sulphur (TS) contents and pH, while only the TN content resulted in significantly different between the two soil layers. Moreover significant differences were identified in the cultivation areas in terms of soil physical properties including clay and sand contents, aggregate stability and organic matter content, whereas the only significant difference found among the soil layers was that of their silt content. Since safflower contains higher amounts of biomass than wheat, we found higher amounts of organic matter content and, therefore, higher amounts of TN and TS content in the soils of the SCA. In addition, due to the fact that wheat contains more cellulose – which takes longer to decompose – the TC content of the soil in the WCA were found to be higher than that of the SCA. The results also revealed that the WCA had a higher carbon storage capacity.
Influence of chosen microbes and some chemical substances on the production of aflatoxins
Authors: Brožková Iveta , Šmahová Petra , Vytřasová Jarmila , Moťková Petra , Pejchalová Marcela , Šilha David
Published: March 2015

Aflatoxins are produced as secondary metabolites by A. flavus, A. parasiticus, A. nomius and A. tamarii. The aflatoxin biosynthetic pathway involves several enzymatic steps and genes (apa-2, ver-1) that appear to be regulated by the aflR gene in these fungi. The aim of this work was the detection of aflatoxins by the HPLC method and the ascertainment of factors influencing their production. A. parasiticus CCM F-108, A. parasiticus CCF 141, A. parasiticus CCF 3137 and two isolates A. flavus were used. These toxigenic isolates were recovered from spice (strain 1) and wraps (strain 2). The gene for the production of aflatoxin B1 for each species of fungi was detected using an optimized PCR method. Rhodotorula spp.*, Lactococcus lactis subsp. lactis CCM 1881, Flavobacterium spp. and fungal strain Pythium oligandrum* were tested for inhibition of aflatoxins production and fungal growth. Having used the HPLC detection, various preservatives (propionic acid, citric acid, potassium sorbate) were tested from the viewpoint of their influence on the growth of aflatoxigenic fungi followed by the production of aflatoxins. The growth of A. flavus and A. parasiticus and aflatoxin production in Potato Dextrose Agar supplemented with propionic acid (1000-2000-3000 mg/kg), citric acid (2000-3000-4000 mg/kg) and potassium sorbate (500-800-1000 mg/kg) was tested by Agar Dilution Method. After 72 h of incubation was evaluated growth of fungi, all samples were frozen for later extraction and aflatoxins quantification by HPLC. Effect of peptone and sucrose additions were studied in yeast extract (2%) supplemented with peptone (5-10-15%) or sucrose (15%). Growth inhibition of Aspergillus by Pythium oligandrum was tested on wood surface. As shown, the highest inhibition effect on the aflatoxins production was obtained when propionic acid was applied in concentrations since 1000 mg/kg. A total inhibition of the fungi growth and aflatoxins production was observed in all samples containing peptone in the concentration range tested. Significant limitation of the growth and production of aflatoxins was also observed in the presence of other microorganisms such like Pythium oligandrum and Rhodotorula spp.
Production of T-2 toxin and deoxynivalenol in the presence of different disinfectants
Authors: Hrubošová Dana , Vytřasová Jarmila , Brožková Iveta
Published: March 2015

The aim of the work was to examine the effect of different disinfectants on production trichothecenes (especially of T-2 toxin and deoxynivalenol). Lipophilicity, chemical structure, the presence of bioactive groups and functional groups in their structure modifies biological activity and toxic potency of trichothecenes. For this reason, limits have been established designating maximum levels of mycotoxins in cereals while maintaining proper growing practices. Appropriate nutritive media were prepared with different concentration of tested disinfectants (Desanal A  plus, ProCura spray and Guaa-Pool) and were inoculated using  Fusarium strains. The density of  Fusarium was 105 spores per mililitre. Nutrient media was cultivated at 15 °C and 25 °C for seven days. The strains of Fusarium graminearum CCM F-683 and Fusarium species (isolated from barley) produced quantities of deoxynivalenol. Fusarium poae CCM F-584 and Fusarium species (isolated from malthouse air) produced quantities of T-2 toxin. Desanal A plus prevented Fusarium growth and production of T-2 toxin and deoxynivalenol at the concentration 10%. It is an alkaline disinfectant on the basis of active chlorine and the surfactant that contains ˂5% of NaClO. ProCura spray at the concentration 0.6% proved to be very effective. This disinfectant contains 35% of propan-1-ol and 25% of propan-2-ol.  Guaa-Pool at the concentration 0.004% proved to be very effective. It is a polymeric disinfectant with anion surface-acting agent and it contains ˂0.9% of polyhexamethylene guanidine hydrochloride and ˂0.2% of alkyl (C12-C16) dimethylbenzyl ammonium chloride. Lower contentration of  disinfectants that  not prevented growth of Fusarium caused higher production  of T-2 toxin and deoxynivalenol. The contents of T-2 toxin and deoxynivalenol were analyzed by enzyme-linked immunosorbent assay (ELISA) using commercially produced kits (Agra Quant® Deoxynivalenol Test kit and Agra Quant® T-2 toxin Test kit). The experiment showed that the variability in the production of T-2 toxin and deoxynivalenol depended on the Fusarium strain used, concentration of disinfectants and temperature of cultivation.
Phacoemulsification with Toric IOL Implantation in Alport Syndrome with Anterior Lenticonus having Spontaneously Ruptured Anterior Capsule
Authors: Agrawal Niraj , Prasad Nayak Durga , Haripriya Aravind , Bhuwania Puja
Published: March 2015

Purpose

To report the outcome of phacoemulsification with toric intraocular lens (IOL) implantation in Alport syndrome with spontaneously ruptured capsule.

Methods

Case report and literature review.

Results

A 2.2-mm clear corneal phacoemulsification with toric lens implantation was done in anterior lenticonus with spontaneously ruptured anterior capsule. The toric IOL was well-centered with good visual outcome.

Conclusions

Safe phacoemulsification with toric IOL implantation is possible in cases with spontaneous rupture of anterior lens capsule. Ability to achieve compact and complete capsulorhexis is one of the key steps to achieve favorable results.
Intraocular Pressure after Intravitreal Injection of Dexamethasone Implant for Macular Edema Resulting from Retinal Vein Occlusion
Authors: Caillaux Violaine , Valtot Françoise , Souied Eric H. , Mimoun Gérard
Published: March 2015

Purpose

A recognized side effect of corticosteroids intravitreal injections (IVT) is the onset of ocular hypertension. The aim of our study was to analyze changes in short-term intraocular pressure (IOP) after IVT of sustained-release dexamethasone implant in order to provide an appropriate monitoring scheme.

Methods

In this retrospective study, the charts of 44 eyes of 42 patients treated by IVT of dexamethasone implant for macular edema resulting from retinal vein occlusion were reviewed. The IOP measurements were performed at baseline and at 15 minutes, 7 days (D7), 1 month (Ml), 2 months (M2), and 4 months (M4) after IVT.

Results

Mean IOP was 13.4 ± 2.5 mm Hg at baseline. Twelve eyes out of 44 (27.3%) were treated with antihypertensive eyedrops for a well-controlled glaucoma at baseline. Following IVT, mean IOP was 11.5 ± 3.6 mm Hg at 15 minutes, 14.7 ± 3.1 mm Hg at D7, 16.4 ± 7.0 mm Hg at M1, 19.3 ± 7.9 mm Hg at M2, and 13.5 ± 3.1 mm Hg at M4. An IOP ≥25 mm Hg or increased by 10 mm Hg or more was not observed in any eye at 15 minutes, D7, or M4 after IVT, but in 8.6% of cases at M1 and in 25% at M2.

Conclusions

It seems reasonable to perform the first IOP monitoring 1 month after IVT of dexamethasone implant and at each efficacy assessment visit (M2, M4). Special attention should be given to patients at risk, such as glaucoma patients. An IOP measurement immediately after IVT and in the following days (1 week) does not seem to be appropriate on a routine basis.
Evaluation of a Pseudo-One-Compartment Model for Phosphorus Kinetics by Later-Phase Dialysate Collection during Blood Purification
Authors: Yashiro Masatomo , Kotera Hirohisa , Matsukawa Makoto , Kita Tomoyuki , Tanaka Hiroshi , Sakai Rumi
Published: March 2015

Purpose

Phosphorus removal is a major issue to assess for physicians engaging in hemodialysis. A pseudo-one-compartment model was reported as a novel model for phosphorus kinetics. We aimed to evaluate the adequacy of this model from the standpoint of the total mass of removed phosphorus during prolonged treatment.

Methods

Dialysate was collected during 6-h hemodialysis and hemodiafiltration treatment in 5 patients. Later-phase (from 4 to 6 h) dialysate was collected separately. Mobilization clearance (Km and dialyzer clearance (K) were calculated by simple arithmetic operations utilizing stable serum phosphorus concentrations in this later phase. Volume of the accessible compartment (V0) was estimated by a fitting method. Amounts of removed phosphorus were calculated with these parameters and compared with measured values. The best sampling time points during treatment were also assessed, when the parameters were determined by serial serum phosphorus concentrations alone.

Results

Pearson's correlation coefficient (R) between calculated and measured values of removed phosphorus was 0.991 and the concordance correlation coefficient (ρ) was 0.987. When Km, K and V0 were determined by serial serum concentrations alone, including those at 0, 1, 4, and 6 h, the calculated mass of removed phosphorus had high R (0.974–0.975) or ρ (0.966–0.972) with the measured values.

Conclusions

We confirmed that a pseudo-one-compartment model is useful for the estimation of removed phosphorus mass during prolonged blood purification by collecting dialysate. When the parameters are determined by a fitting method using serial serum concentrations alone, sampling at 0, 1, 4, and 6 h seems to be adequate.
NT-proBNP and Troponin T Levels Differ after Haemodialysis with a Low versus High Flux Membrane
Authors: Laveborn Emilie , Lindmark Krister , Skagerlind Malin , Stegmayr Bernd
Published: March 2015

Background

Brain natriuretic peptide (BNP), N-terminal-proBNP (NT-proBNP), and high sensitive cardiac troponin T (TnT) are markers that are elevated in chronic kidney disease and correlate with increased risk of mortality. Data are conflicting on the effect of biomarker levels by hemodialysis (HD). Our aim was to clarify to what extent HD with low-flux (LF) versus high-flux (HF) membranes affects the plasma levels of BNP, NT-proBNP, and TnT.

Methods and Materials

31 HD patients were included in a crossover design, randomized to start dialysis with a LF-HD or HF-HD dialyzer. Each patient was his/her own control. The dialyses included in the study were the first treatments of two consecutive weeks with each mode of dialysis. Patients normally on hemodiafiltration (HDF) also performed a HDF the third week. Values after HD were corrected for extent of ultrafiltration.

Results

During LF-HD the biomarkers NT-proBNP and TnT increased (15 versus 6%, P≤.001) while there was a slight decrease in BNP ( P<.05). During HF-HD the NT-proBNP, BNP and TnT levels decreased ( P≤.01 for all). During HDF all three markers decreased ( P<.01 for all). The rise in TnT during LF-HD correlated with dialysis vintage (months on HD, r = .407, P = .026), Kt/V-urea (r = .383, P = .037), HD time in hours/treatment (r = .447, P = .013) and inversely with residual urinary output (r = -.495, P = .005). The baseline levels of BNP and NT-proBNP correlated with blood pressure.

Conclusions

Cardiac biomarkers increase slightly during LF-HD. A HF-HD eliminates the biomarkers and can mask increases caused by, e.g., myocardial infarction.
Factors Associated with Albumin Loss in Post-Dilution Hemodiafiltration and Nutritional Consequences
Authors: Fournier Anne , Birmelé Béatrice , François Maud , Prat Louis , Halimi Jean-Michel
Published: March 2015

Introduction

Hemodiafiltration is currently one of the most effective techniques of extra-renal purification but results in an increase of albumin loss in dialysate. We aimed to determine the factors associated with albumin loss during post-dilution hemodiafiltration, compare an “automatic” mode of infusate flow control versus a “manual” control, and assess the potential nutritional impact.

Methods

This prospective observational study included all hemodialysis patients in our institution who underwent post-dilution hemodiafiltration 3 times a week on a Fresenius 5008 for at least 2 months. At each session, albumin content was measured in a representative effluent dialysate volume. The automatic mode of the Fresenius 5008 was used for automatic infusate flow control.

Results

In all, 18 patients (mean age 60.7 ± 15 years) underwent 85 post-dilution hemodiafiltration sessions. The mean albumin loss was 3134 ± 2450 mg/session. Albumin loss was significantly affected by infusate flow, infusate volume, transmembrane pressure and ultrafiltration volume. The loss was greater with Toraysulfone and FX 1000 membranes rather than FX 80 or FX 100 membranes. With AutoSub rather than manual control, infusate flow was greater ( P<.001), transmembrane pressure was higher (P = .004), and the albumin loss was greater (P = .010). However, there was no correlation between albumin loss and nutritional variables.

Conclusions

Albumin loss during post-dilution hemodiafiltration was correlated with increased transmembrane pressure and infusate flow, especially AutoSub flow control, and type of membrane. However, this loss, when moderate, did not seem to affect nutritional aspects and should not limit the use of hemodiafiltration.
Buccal Mucosa Repair with Electrospun Silk Fibroin Matrix in a Rat Model
Authors: Tang Jing , Han Yongjie , Zhang Feng , Ge Zili , Liu Xi , Lu Qiang
Published: March 2015

Introduction

Biomimic electrospun matrix derived from silk fibroin nanofiber solution was recently prepared in our group. The feasibility of the matrix as mucosa repair scaffold was evaluated in a rat model in the present study.

Methods

Full thickness wound was established on the buccal mucosa of male Wister rats via microscopic oral surgery. 80 rats were randomly assigned into 4 groups: ( 1 ) silk fibroin matrix, ( 2 ) commercial cowhide acellular dermal matrix (Heal-AII), ( 3 ) commercial acellular dermal matrix of human skin (RENOV), and ( 4 ) vaseline gauze, respectively.

Results

The silk fibroin matrix showed similar repair performance compared to the commercial acellular dermal matrices, implying promising applications in mucosa regeneration. More importantly, the silk fibroin matrix showed better wound healing ability, improved wound shrinkage inhibition, and reduced local immunological incompatibility.

Conclusions

The silk fibroin scaffold performed satisfied in scar tissue inhibition and epidermis regeneration. Taking into account its improved mechanical properties, the biomimic electrospun silk matrix could become a promising substitute of acellular dermal matrix in clinical applications.
A Novel Peritoneum Derived Vascular Prosthesis Formed on a Latex Catheter in an SDF-1 Chemokine Enriched Environment: A Pilot Study
Authors: Ulczok Rafał , Milewski Krzysztof , Bis Jaroslaw , Samborski Stefan , Krauze Agata , Jelonek Michał , Guc Michal , Smyczek Dominika , Aboodi Michael , Maciejewski Adam , Buszman Pawel E. , Bochenek Andrzej , Wojakowski Wojciech , Krejca Michal
Published: March 2015

Introduction

Although saphenous vein grafts are widely used conduits for coronary artery bypass graft surgery, their clinical value remains limited due to high failure rates. The aim of the study was to evaluate feasibility, safety, and biocompatibility of peritoneal derived vascular grafts (PDVG) formed on a silicone-coated, latex, Foley catheter in a stromal cell-derived factor (SDF-1)- enriched environment.

Methods

Foley catheters were implanted into the parietal wall of 8 sheep. After 21 days the peritoneal cavity was re-opened and the newly formed tissue fragments were harvested. The animals were randomly assigned into: ( 1 ) study group in which conduits were incubated in a solution containing SDF-1, ( 2 ) control group without SDF-1 incubation. Left carotid arteries were accessed and “end-to-side” anastomoses were performed. Biological materials for histological examination were taken at 4, 7, 10, and 14 days.

Results and Conclusions

The study proved safety, feasibility, and biocompatibility of PDVG formed on the basis of a silicone-coated, latex catheter in an SDF-1 chemokine-enriched environment. These biological grafts effectively integrated with the native high-pressure arterial environment in an ovine model and provided favorable vascular profile. The potential clinical value of this technology needs to be further elucidated in long-term preclinical and clinical studies.