bluuebunny/crossref_metadata_2025 huggingface dataset:
Spatial and temporal variability of bat foraging in a western European low mountain range forest
Authors: Kusch Jürgen , Idelberger Sylvia
Published: July 2007

We monitored echolocation calls to measure the flight and foraging activity
of European bats at twenty-four locations in the Palatinate Forest, Germany.
Bats' flight activities correlated with their foraging activities at different sites.
The distribution of bat foraging sites may be patchy even in a continuous forest
habitat. Pipistrelle bats changed some of their foraging patches during the
summer-season, most probably due to temporal differences of the resource
densities at those patches. Daubenton's bats in contrast showed steadily high
activities at two investigated forest lakes. The feeding buzz rate declined during
five hours of nightly bat foraging. The nocturnal bat activity did not
change significantly during this time, with the exception of few patches. Food
resources as well as additional factors, like acoustical landmarks that enable
orienting of echolocating bats, and habitat features that allow special foraging
strategies should influence the quality of patches and their use by bats. The
use of one, or of different foraging patches during the year, may depend on
the seasonal constancy or variability of resources, on the degree of isolation of
a patch type, and on the species specific foraging strategy.
Diet diversity of white-tailed deer (Odocoileus virginianus) in a tropical dry forest in Mexico
Authors: Arceo Gloria , Mandujano Salvador , Gallina Sonia , Perez-Jimenez Luis Alfredo
Published: July 2007

We report on diversity in the diet of white-tailed deer (Odocoileus virginianus)
in a Mexican tropical dry forest. Diet was estimated using the microhistological
analysis of plant epidermis in deer pellet-groups. The sampling was from
1993 to 1994. From the rainy to dry season, the richness and diversity of the
families and species in the diet increased and botanical composition changed.
Deer selected 82 plant species from 20 families; however, 12 species represented
50% of the annual diet. Flowers and fruits of arboreal species were
important during the dry season, as were young leaves of shrub and vine
species during the rainy season. Despite the small size of white-tailed deer in
this tropical dry forest study area, foraging strategies there were similar to
those observed in temperate forests.
Small mammals of Maulino forest remnants, a vanishing ecosystem of south-central Chile
Authors: Saavedra Bárbara , Simonetti Javier A.
Published: July 2007

The Maulino forest, located at the coastal range of south central Chile, has
been severely disrupted by intense human activities. Currently, landscape is
dominated by large extensions of plantations of Monterrey pine, where remnants
of native forest are immersed. Here, we assess consequences of Maulino
forest fragmentation and habitat replacement upon small mammal fauna. We
describe habitat characteristics, small mammal's composition and abundance
in native forests (fragmented and continuous), but also in Pinus plantation.
Population and body condition were compared among habitats, along with
movement among native and Pinus forests. Higher species richness was found
in continuous forest comprising Abrothrix longipilis, A. olivaceus, Oligoryzomys
longicaudatus, Irenomys tarsalis, Geoxus valdivianus, Rattus rattus, Octodon
bridgesi, Thylamys elegans, and Dromiciops gliroides. Higher abundance was
observed in fragmented forest and Pinus plantations, where A. longipilis,
A. olivaceus, O. longicaudatus, and T. elegans accounted for 80% of total captures.
Population structure and body size were not affected negatively by fragmentation
and habitat replacement, although habitat characteristics differed
among surveyed habitats. Fragmentation of Maulino forests seems to have a
significant impact on overall small mammal's richness, threatening the persistence
of rare taxa of small mammals. Conservation and management practices
are discussed to favor protection of this highly endangered habitat.
Piezo-assisted nuclear transfer affects cloning efficiency and may cause apoptosis
Authors: Yu Yang , Ding Chenhui , Wang Eryao , Chen Xinjie , Li Xuemei , Zhao Chunli , Fan Yong , Wang Liu , Beaujean Nathalie , Zhou Qi , Jouneau Alice , Ji Weizhi
Published: July 2007

Even though it generates healthy adults, nuclear transfer in mammals remains an inefficient process. Mainly attributed to abnormal reprograming of the donor chromatin, this inefficiency may also be caused at least partly by a specific effect of the cloning technique which has not yet been well investigated. There are two main procedures for transferring nuclei into enucleated oocytes: fusion and piezoelectric microinjection, the latter being used mostly in mice. We have, therefore, decided to compare the quality and the developmental ability, both in vivo and in vitro, of embryos reconstructed with electrofusion or piezoelectric injection. In addition, the effect of piezo setups of differing electric strengths was investigated. Along with the record of the rate of development, we compared the nuclear integrity in the blastomeres during the first cleavages as well as the morphological and cellular quality of the blastocysts. Our results show that the piezo-assisted micromanipulation can induce DNA damage in the reconstructed embryos, apoptosis, and reduced cell numbers in blastocysts as well as a lower rate of development to term. Even if piezo-driven injection facilitates a faster and more efficient rate of reconstruction, it should be used with precaution and with as low parameters as possible.
Nodal signalling and apoptosis
Authors: Wang Hongmei , Tsang Benjamin K
Published: July 2007

Nodal, a member of the transforming growth factor β family, was first cloned from a 7.5 day post-coitum mouse embryo cDNA library. Nodal exerts its biological effects by signalling through its types I and II serine/threonine kinase receptor complex and intracellular Smad proteins. The type II receptors for Nodal are Activin type II receptors ActRIIA and ActRIIB, whereas the putative type I receptors are Activin receptor like kinase (ALK) 4 and ALK7. The main Smad proteins involved in Nodal signalling are Smad2 and Smad3. Studies of Nodal in adult tissues indicate that it is pro-apoptotic in rat ovarian granulosa cells, human trophoblast cells and human ovarian epithelial cancer cells and is growth inhibitory in the latter two cell types. This review summarises the progress made on the functions of Nodal in the apoptosis of adult tissues, especially in the ovary and placenta.
Joint influence of river stream, water level and wind waves on the height of sand bar in a river mouth
Authors: Laanearu J. , Koppel T. , Soomere T. , Davies P.A.
Published: July 2007

The hydraulics theory and wind-wave modelling are used to model annual changes of a threshold (sand bar) height at the mouth of the Narva River in 2002. The changes in the threshold height are attributed to two mechanisms: the cross-shore sediment transport driven by the river flow that erodes the obstacle and the long-shore transport forced by waves that increases the threshold height. It is shown that the flow stratification in the river mouth switches between one- and two-layer modes in different seasons, depending on variations of water level, river discharge and wave activity.
Classification of Indian meteorological stations using cluster and fuzzy cluster analysis, and Kohonen artificial neural networks
Authors: Srinivasa Raju K. , Nagesh Kumar D.
Published: July 2007

The present study deals with the application of cluster analysis, Fuzzy Cluster Analysis (FCA) and Kohonen Artificial Neural Networks (KANN) methods for classification of 159 meteorological stations in India into meteorologically homogeneous groups. Eight parameters, namely latitude, longitude, elevation, average temperature, humidity, wind speed, sunshine hours and solar radiation, are considered as the classification criteria for grouping. The optimal number of groups is determined as 14 based on the Davies–Bouldin index approach. It is observed that the FCA approach performed better than the other two methodologies for the present study.
Effect of temporal rainfall distribution and soil type on soil moisture and runoff generation in semi-arid Zimbabwe
Authors: Mugabe F.T. , Hodnett M.G. , Senzanje A.
Published: July 2007

This paper examines the effect of temporal rainfall distribution on soil moisture and runoff generation in the 5.9 km2 Mutangi catchment in semi-arid Zimbabwe. Rainfall, soil moisture and runoff were measured during the 1999/00 and 2000/01 rainy seasons during which periods 755 mm and 615 mm of rainfall were received, respectively. The percentage of rainfall totals in these periods were 58% and 69%, respectively, in February. The total catchment runoff was 102 mm and 63 mm, of which 52% and 49% were recorded over 6 and 4 d in 2000 and 2001, respectively. Baseflow was negligible. Rainfall intensities were generally low. In the 1999/00 season there were 2 and 8 h with intensities >20 mm h−1 and 10 mm h−1, respectively. Some runoff appears to be generated by Hortonian overland flow (HOF), mainly in the early wet season before ploughing creates a rougher soil surface. The dominant process of runoff in this catchment was saturated overland flow (SOF), which occurs when the soils become saturated from below. The sodic soils along the stream channels appear to generate most of the runoff because of their small capacity to store water before saturation. The ridge soils are coarse sands, with a large capacity to store rainfall. The transitional (slope) soils have an intermediate capacity to store water. If there is a sequence of daily events that completely fills the storage available in both the sodic and transitional soils, and which begins to saturate the ridge soils, there could be very large amounts of runoff (>50% of the daily rainfall). The occurrence of such runoff events depends very heavily on the distribution of rainfall. Dry spells between rain events create storage, thereby reducing the risk of runoff from the next events.
P-pollution in a heavily urbanized river basin from point and diffuse sources: the River Ruhr case study (Germany)
Authors: Tetzlaff B. , Wendland F.
Published: July 2007

An area-differentiated model approach (MEPhos) for the quantification of mean annual P-inputs from point and diffuse sources is presented. The following pathways are considered: artificial drainage, wash-off, groundwater outflow, soil erosion, rainwater sewers, combined sewer overflows, municipal waste water treatment plants and industrial effluents. Based on the modelling results “hot spots” for high P-loads can be localized and management option for the input reduction to surface waters proposed. The model is applied to the River Ruhr basin (4,485 km2) in Germany with contrasting natural conditions, land use patterns as well as population and industry densities.
Integrated modelling of nitrate loads to coastal waters and land rent applied to catchment-scale water management
Authors: Refsgaard A. , Jacobsen T. , Jacobsen B. , Ørum J.-E.
Published: July 2007

The EU Water Framework Directive (WFD) requires an integrated approach to river basin management in order to meet environmental and ecological objectives. This paper presents concepts and full-scale application of an integrated modelling framework. The Ringkoebing Fjord basin is characterized by intensive agricultural production and leakage of nitrate constitute a major pollution problem with respect groundwater aquifers (drinking water), fresh surface water systems (water quality of lakes) and coastal receiving waters (eutrophication). The case study presented illustrates an advanced modelling approach applied in river basin management. Point sources (e.g. sewage treatment plant discharges) and distributed diffuse sources (nitrate leakage) are included to provide a modelling tool capable of simulating pollution transport from source to recipient to analyse the effects of specific, localized basin water management plans. The paper also includes a land rent modelling approach which can be used to choose the most cost-effective measures and the location of these measures. As a forerunner to the use of basin-scale models in WFD basin water management plans this project demonstrates the potential and limitations of comprehensive, integrated modelling tools.
Using precise data sets on farming and pesticide properties to verify a diffuse pollution hydrological model for predicting pesticide concentration
Authors: Matsui Y. , Narita K. , Inoue T. , Matsushita T.
Published: July 2007

Verification of a diffuse pollution model involves comparing results actually observed with those predicted by precise model inputs. Acquisition of precise model inputs is, however, problematic. In particular, when the target catchment is large and substantial estimation uncertainty exists, not only model verification but also prediction is difficult. Therefore, in this study, rice-farming data were collected for all paddy fields from all farmers in a catchment and pesticide adsorption and degradation rates in paddy field soil samples were measured to obtain precise model inputs. The model inputs successfully verified the model's capability to predict pesticide concentrations in river water. Sensitivity analyses of the model inputs elucidated the processes significantly affecting pesticide runoff from rice farms. Pesticide adsorption and degradation rates of the soil did not significantly affect pesticide concentrations, although pesticide discharge to river water accounted for less than 50% of the total quantity of pesticide applied to fields, possibly owing to pesticide adsorption and degradation. The timing of increases in pesticide concentrations in river water was affected mostly by the farming schedule, including the time of pesticide application and irrigation, and secondarily by rainfall events.
Sorption behaviour of oxadiazon in tropical rice soils
Authors: Hoque M.E. , Wilkins R.M. , Kennedy A. , Garratt J.A.
Published: July 2007

The soprtion behaviour of a pre-emergent herbicide, oxadiazon (5-tert-butyl-3-(2,4-dichloro-5-isopropoxyphenyl)-1,3,4-oxadiazol-2 (3H)-one) was investigated in tropical rice soils using a batch equilibrium method. There is no information available on the fate of oxadiazon in Bangladeshi soils; Bangladesh rice soil is a unique environment. The experiment was performed using radiolabelled (14C) oxadiazon. The sorption and desorption isotherm of oxadiazon was described using the Freundlich equation. L-type sorption isotherms were observed. The correlation coefficient (r2) was 0.995 to 0.997 and the linearity of the slope was in the range 0.96–1.07. Sorption of oxadiazon was related to organic carbon. Sorption of oxadiazon by soil was a rapid process; sorption kinetics indicated that most of the sorption occurred within two hours. Changes in sorption of oxadiazon by soils was investigated by repeated application. Sorption after the first cycle was in the range 81–92% whereas sorption capacity decreased in the following cycles.
Application of environmental impact quotient model to Kumluca region, Turkey to determine environmental impacts of pesticides
Authors: Muhammetoglu A. , Uslu B.
Published: July 2007

Besides the new developments in agricultural technology, intensive use of pesticides poses a great environmental hazard. The unthinking use of pesticides leads to contamination of air, water and soil. There are several pesticide risk indicator models available in the literature to assess pesticide impacts on the applicator and the ecosystem which is an important issue. This paper refers to an application of a pesticide risk indicator model, called Environmental Impact Quotient (EIQ) which was developed to measure the environmental impacts of pesticide active ingredients used in vegetable and fruit production. The application site is the Kumluca region of Turkey, which is well known for its intensive agricultural activities. As the first step in the model application, EIQ values have been calculated for 35 commonly used pesticides in Kumluca. EIQ values were then turned into EIQ field use rating results based on the active ingredient percent and application rate. Furthermore, some pesticide management scenarios were evaluated to select the least detrimental pesticide by comparing EIQ model results. The EIQ model is an easily applied and very helpful tool for pest management practitioners and agricultural specialists. It can be used efficiently to compare different agricultural pest management strategies or programs.
Simultaneous estimation of model parameters and diffuse pollution sources for river water quality modeling
Authors: Jun K.S. , Kang J.W. , Lee K.S.
Published: July 2007

Diffuse pollution sources along a stream reach are very difficult to both monitor and estimate. In this paper, a systematic method using an optimal estimation algorithm is presented for simultaneous estimation of diffuse pollution and model parameters in a stream water quality model. It was applied with the QUAL2E model to the South Han River in South Korea for optimal estimation of kinetic constants and diffuse loads along the river. Initial calibration results for kinetic constants selected from a sensitivity analysis reveal that diffuse source inputs for nitrogen and phosphorus are essential to satisfy the system mass balance. Diffuse loads for total nitrogen and total phosphorus were estimated by solving the expanded inverse problem. Comparison of kinetic constants estimated simultaneously with diffuse sources to those estimated without diffuse loads, suggests that diffuse sources must be included in the optimization not only for its own estimation but also for adequate estimation of the model parameters. Application of the optimization method to river water quality modeling is discussed in terms of the sensitivity coefficient matrix structure.
Brake wear from vehicles as an important source of diffuse copper pollution
Authors: Hulskotte J.H.J. , Denier van der Gon H.A.C. , Visschedijk A.J.H. , Schaap M.
Published: July 2007

In this article we show that brake wear from road traffic vehicles is an important source of atmospheric (particulate) copper concentrations in Europe. Consequently, brake wear also contributes significantly to deposition fluxes of copper to surface waters. We estimated the copper emission due to brake wear to be 2.4 kiloton per year. For comparison, the official database for Europe (without brake wear) totals 2.6 kiloton per year. In Western Europe the brake wear emissions dominate the total emission of copper. Using the spatially resolved emission data, copper distributions over Europe were calculated with the LOTOS-EUROS model. Without brake wear the model underestimates observed copper concentrations by a factor of 3, which is in accordance with other studies. Including the brake wear emissions largely removes the bias. We find that 75% of the atmospheric copper input in the North Sea may be due to brake wear. We estimate that about 25% of the total copper input in the Dutch part of the North Sea stems from brake wear. Although the estimated brake wear copper emission is associated with a large uncertainty, it significantly improves our understanding of the copper cycle in the environment.
Nitrogen fertilizer impact on the Wilmot watershed aquifer in Prince Edward Island, Canada
Authors: van Bochove E. , Savard M.M. , Thériault G. , Cherif R. , Ziadi N. , MacLeod J.
Published: July 2007

The objective of this study is to estimate the soil N flux from the vadose zone to the aquifer of the Wilmot watershed (Prince Edward Island, Canada) for a typical three-year cropping rotation (barley–red clover–potato). A conceptual model estimates that 199–221 tons of N were yearly available for leaching at the watershed scale. A significant portion of this N amount was available for leaching at the end of the crop season representing 80–90% of the annual N balance. Drainage water nitrate concentrations were significantly higher after the potato-rotation year than during the crop season. Low nitrate concentrations were measured at spring thaw indicating that most of the nitrate available from the preceding potato crop season was likely leached at the end of fall or during winter. Early spring ionic exchange membrane sampling show a large availability of nitrate in soil possibly throughout winter as well, resulting from soil N mineralization and nitrification over the winter period. These findings are corroborated by the isotope natural abundance analysis of nitrate in groundwater implying that nitrifiers are significantly active during winter, as well as during the crop season, and that leaching of soil nitrates with seasonal signals takes place whenever recharge is occurring.
Long-time risk of groundwater/drinking water pollution with sulphuric compounds beneath burned peatlands in Indonesia
Authors: Hammen V.C.
Published: July 2007

Smoke-haze episodes caused by vegetation and peat fires affect parts of Indonesia every year with significant impacts on human health and climate. The forest fires 1997/1998 were by far the largest in Indonesian history, burning between 5 and 8 million hectares before they were stopped by the monsoon rains in December 1997. Fires sprang up again in 1998 on Kalimantan when monsoon rain paused. Peat forests and peatlands are in particular severely affected. In the 1997/1998 haze event, 2.1–2.5 million hectare of peat swamp forest burnt in Indonesia. The remaining ash contains high concentrations of sulphur and sulphuric compounds which eventually leach into the groundwater, thus polluting groundwater and drinking water. The thicker the peat layer is and the higher the number of fires in the respective area the more sulphuric compounds will leach into the groundwater. Risk areas for the sulphur loads of the ash are identified.
Treatment of distillery vinasse in a high rate anaerobic reactor using low density polyethylene supports
Authors: Thanikal J.V. , Torrijos M. , Habouzit F. , Moletta R.
Published: July 2007

An anaerobic fixed bed reactor, filled with small floating supports of polyethylene material (Bioflow 30) as inert media, was operated for 6 months to treat vinasse (wine residue after distillation). Bioflow 30 has a density of 0.93 and a specific area of 320 m2/m3. The experimental results showed that the efficiency of the reactor in removal of soluble COD was very good with a maximum organic loading rate of more than 30 g of COD/L.d and a COD removal efficiency of more than 80%. Bioflow 30 showed a high capability of biomass retention with 4–6 g of dried solids per support. Thus, at the end of the experiment, the fixed biomass represented 57 g of solids/L of reactor. The visual observation of the supports and the specific activity (0.54 g COD/g solids.d) of the fixed solids, which remained close to the values obtained with suspended biomass, showed that entrapment was playing an important role in the retention of the biomass inside the reactor. It was then possible to operate the reactor with a very high loading rate as the result of the increase of the solids in the reactor and the maintaining of the specific activity. Bioflow 30 is then an excellent support for use in a high rate anaerobic fixed bed.
Selected experiences in Chile for the application of UASB technology for vinasse treatment
Authors: Chamy R. , Pizarro C. , Vivanco E. , Schiappacasse M.C. , Jeison D. , Poirrier P. , Ruiz-Filippi G.
Published: July 2007

One of the research areas is the agricultural use of treated wastewaters, because it represents a unique opportunity to solve the problem of water supply for irrigation and at the same time the disposal of treated water. Anaerobic digestion appears as an interesting alternative, since anaerobically treated wastewaters can be used for irrigation purposes. These considerations are applied to the Chilean pisco industry (a traditional alcoholic drink, prepared by distillation of wine made mainly from Muscatel grapes), where high concentrated wastewaters are produced: vinasses originate as a residue from the distillation operation.

Two laboratory reactors fed with wine vinasses, a UASB and an EGSB, were used in order to study the anaerobic treatability of the wastewater. Then, a pilot reactor was built (60 m3 UASB digester) and treated water was used to irrigate eucalyptus trees. Finally a 300 m3 reactor, including biogas treatment for its reuse, was developed. Results showed, both at laboratory and full scale, that anaerobic treatment is suitable for pisco's wastewaters, and also that the nutrient content of treated water can be beneficial for plant growth, reducing the need for fertilizers.

Another kind of investigation was carried out in order to study the stability of anaerobic granules and how it can be recovered. UASB and EGSB were fed with low, medium and high load wastewaters, in order to evaluate possible fluctuations in the productive process. From these results, it was possible to propose and to apply recovery techniques to the digesters when they are destabilized.
Bioremediation of a wine distillery wastewater using white rot fungi and the subsequent production of laccase
Authors: Strong P.J. , Burgess J.E.
Published: July 2007

The aim of this work was to ascertain whether a submerged culture of a white rot fungus could be used to treat distillery wastewater, and whether the compounds present in the wastewater would stimulate laccase production. Trametes pubescens MB 89, Ceriporiopsissubvermispora, Pycnoporus cinnabarinus and UD4 were screened for their ability for the bioremediation of a raw, untreated distillery wastewater as well as distillery wastewater that had been pretreated by polyvinylpolypyrrolidone. Suitability of each strain was measured as a function of decreasing the chemical oxygen demand (COD) and total phenolic compounds concentration and the colour of the wastewater, while simultaneously producing laccase in high titres. After screening, T. pubescens MB 89 was used further in flask cultures and attained 79±1.1% COD removal, 80±4.6% total phenols removal, 71±1.6% decrease in colour at an absorbance of 500 nm and increased the pH from 5.3 to near-neutral. Laccase activity in flask cultures peaked at 4,644±228 units/l, while the activity in a 50 l bubble lift reactor peaked at 12,966±71 units/l. Trametes pubescens MB 89 greatly improved the quality of a wastewater known for toxicity towards biological treatment systems, while simultaneously producing an industrially relevant enzyme.
New Strategies for Emerging Domestic Sovereign Bond Markets in the Global Financial Landscape
Authors: Blommestein Hans J. , Santiso Javier
Published: July 2007

The forces shaping the revolution in banking and capital markets have radically changed the financial landscape during the past three decades. A remarkable feature of this changing new landscape has been the astonishing rate of internationalisation of the financial system in the last two decades, with emerging markets becoming increasingly important participants.

At times this participation has led to excessive reliance on foreign financing, making the participation of these countries in the global financial system more vulnerable to shifts in expectations and perceptions. The sovereign debt management strategy suffered from many structural weaknesses, failing to take into account international best practices in financing budget deficits and developing domestic government securities markets. Consequently, emerging markets experienced episodes of serious financial crises.

Against this background, this article focuses on new and more sophisticated strategies to develop domestic bond markets, taking into account the risk profile, complexities and other constraints of emerging markets. The article's central thesis is that risk-based public debt management and liquid domestic bond markets are important mutually reinforcing strategies for emerging financial markets to attain (1) enhanced financial stability, and (2) a more successful participation in the global financial landscape. It will also be shown that this twin-strategies approach requires taking a macroeconomic policy perspective.
Market and Welfare Effects of Collusion with Reference to Multi-Product Food Oligopoly and Oligopsony
Authors: Bouras Brahim
Published: July 2007

Among the dominant firms in the US meat and grain business, many produce several products, some of which are demand-related. Yet, virtually all research on collusion among those firms focuses on a single product. This paper uses a game-theoretic model to investigate the conditions under which multi-product food firms producing demand-related goods have incentives to collude, and examines the welfare implications of collusion for participants in a vertical marketing chain. I show that multi-product food firms have a greater incentive to collude when they become more efficient. In contrast to previous work, I find that the effect of the degree of product substitutability on collusion sustainability hinges on the cost effect arising from joint production. From a policy standpoint, I show that mergers between single-product firms producing demand-related goods under certain conditions may hinder collusion.
Multiobjective Dynamic Optimization of an Industrial Steam Reformer with Genetic Algorithms
Authors: Alizadeh Ali , Mostoufi Navid , Jalali-Farahani Farhang
Published: July 2007

An industrial steam reformer of a methanol plant was modeled at a dynamic condition in which a one dimensional homogeneous model was coupled with a verified kinetics from the literature. A close agreement was observed between the results of the model and industrial data from a real plant at steady state conditions. The open loop response of the system to switching between two operating conditions was investigated and shown that the produced synthesis gas during the transition period would be unsuitable for the downstream methanol converter. The genetic algorithm was then employed to perform a multi-objective dynamic optimization on the reactor performance in case of switching the feed and operating conditions. Maximization of methane conversion and minimization of a stoichiometric parameter, were considered as the two objectives' functions that were optimized for a fixed feed rate of methane to the existing unit. The results of the dynamic optimization for the specified reformer configuration were achieved after switching the operating condition. Results of the optimization showed that the produced synthesis gas would stay in its acceptable limits in terms of quality of the feed of the methanol converter and also, the final conversion of the reformer would be improved compared to the steady state condition. This procedure could be applied to the advanced process control of the methanol plant.
A Comprehensive Approach to Reaction Engineering
Authors: Mahecha-Botero Andres , Grace John R. , Elnashaie Said S.E.H. , Lim C. Jim
Published: July 2007

A generalized modeling approach is used to develop a systematic algorithm for formulating and solving chemical/biochemical reaction engineering problems. This systematic approach is general enough that it can treat different systems with varying degrees of complexity utilizing the same methodology. The procedure can be used in both introductory and advanced chemical/biochemical reaction engineering courses. This will provide the students with a powerful "toolkit" to tackle a wide range of academic and industrial engineering problems as well as a solid starting point for developing research projects in this field. This may also allow the students to have a better understanding of the multiple phenomena encountered in chemical/biochemical engineering systems and encourage them to prepare models at an optimum level of sophistication for design, optimization, and exploration of novel ideas.
Cox Survival Analysis of Microarray Gene Expression Data Using Correlation Principal Component Regression
Authors: Zhao Qiang , Sun Jianguo
Published: July 2007

Statistical analysis of microarray gene expression data has recently attracted a great deal of attention. One problem of interest is to relate genes to survival outcomes of patients with the purpose of building regression models for the prediction of future patients' survival based on their gene expression data. For this, several authors have discussed the use of the proportional hazards or Cox model after reducing the dimension of the gene expression data. This paper presents a new approach to conduct the Cox survival analysis of microarray gene expression data with the focus on models' predictive ability. The method modifies the correlation principal component regression (Sun, 1995) to handle the censoring problem of survival data. The results based on simulated data and a set of publicly available data on diffuse large B-cell lymphoma show that the proposed method works well in terms of models' robustness and predictive ability in comparison with some existing partial least squares approaches. Also, the new approach is simpler and easy to implement.
A Method for Meta-Analysis of Case-Control Genetic Association Studies Using Logistic Regression
Authors: Bagos Pantelis G , Nikolopoulos Georgios K
Published: July 2007

We propose here a simple and robust approach for meta-analysis of molecular association studies. Making use of the binary structure of the data, and by treating the genotypes as independent variables in a logistic regression, we apply a simple and commonly used methodology that performs satisfactorily, being at the same time very flexible. We present simple tests for detecting heterogeneity and we describe a random effects extension of the method in order to allow for between studies heterogeneity. We derive also simple tests for assessing the most plausible genetic model of inheritance, and its between-studies heterogeneity as well as adjusting for covariates. The methodology introduced here is easily extended in cases with polytomous or continuous outcomes as well as in cases with more than two alleles. We apply the methodology in several published meta-analyses of genetic association studies with very encouraging results. The main advantages of the proposed methodology is its flexibility and the ease of use, while at the same time covers almost every aspect of a meta-analysis providing overall estimates without the need of multiple comparisons. We anticipate that this simple method would be used in the future in meta-analyses of genetic association studies. A STATA command performing all the available computations is available at http://bioinformatics.biol.uoa.gr/~pbagos/metagen/.
Attitudes and Values of Nurse Educators: An International Survey
Authors: Haigh Carol , Johnson Martin
Published: July 2007

Within the last two decades the holistic care of patients has become increasingly important to nurse practitioners and educators. This has led to a move from a wholly biological approach to care to one that requires greater moral reasoning and value judgments by practitioners. There is a significant body of literature suggesting that values developed by students throughout their education can be affected to varying degrees by the nurse educators to whom the student is exposed. Yet, there is a dearth of research into what the values held by such nurse educators may be. A questionnaire was distributed to nurse educators from nineteen different countries at an international conference. Overall, educators reported high regard for the values of honesty and intellectualism, whilst maintaining a more cautious, although still positive, attitude toward altruism in health care.
Letter: Observation-Based Analysis and Industry Studies
Authors: Giarratani Frank
Published: July 2007

Observation-based analysis at the firm and plant level is alive, well, and growing, according to Frank Giarratani. More than eight hundred scholars, including many economists, embrace observation-based analysis, and identify with industry studies as a research field based on this principle.
A Natural, Multi-Mechanistic Supplement Approach for Improving Cardiovascular Risk Factors
Authors: Vinson Joe , Cai Xinxing , Al Kharrat Hassan
Published: July 2007

Cardiovascular disease is the number one cause of death in the developed world. With the emergence of herbal preparations, the number of people using these products to improve their health is growing. The purpose of this study is to investigate a product that contains a number of ingredients that singly have been shown to lower lipids.A commercial combination herbal extract containing phytosterols, fiber, and other plant extracts with lipid-lowering properties was investigated using a double blind placebo-controlled clinical study. There were two active phases and one placebo phase, each two months in length. Two groups of subjects were studied; one group was taking statin drugs and the other was not taking any cholesterol-lowering drugs but had high cholesterol.Safety was investigated with a battery of tests including blood chemistry, coagulation, hematology, blood pressure and weight. Efficacy for heart disease risk factors were evaluated and included lipids, homocysteine, and C-reactive protein. Glucose was also measured.There were no significant side effects with the active supplement and no changes in liver enzymes indicating a lack of toxicity. The product (11 g) taken daily and compared to placebo significantly lowered cholesterol, LDL and the risk ratio, and glucose only in the group not taking statins. There was no significant change vs. the placebo for two other heart disease risk factors, homocysteine and high sensitivity C-reactive protein. After combining both subject groups, the product lowered total cholesterol 4.8% (p < 0.001), decreased LDL 8.3% (p < 0.001) and lowered the cholesterol/HDL (heart disease risk ratio) 9.4% (p < 0.001). Triglycerides were also improved and declined 11.6%, but the change was not significant. Glucose was also significantly decreased 4.8% (p < 0.001).The product with low doses of herbal ingredients was shown to be safe and effective for improving the lipid profile and thus decreasing the risk of heart disease. An additional benefit was that glucose was lowered by the supplement.
Inactivation of Lemon Pectinesterase by Thermosonication
Authors: Kuldiloke Jarupan , Eshtiaghi Mohammad , Zenker Mattias , Knorr Dietrich
Published: July 2007

The combined effect of ultrasound and temperature (thermosonication) on the inactivation of lemon pectinesterase was examined. The experiments were separated into two groups. The first ones were performed at 40°C-90°C, ambient pressure with ultrasonication of 20 kHz. The other ones were carried out at 40°C-90°C without ultrasonication. After heating at 50°C with the ultrasonic treatment for 63 min, the residual activity was 83% decreased whereas without the ultrasound the residual activity was only 30% decreased. The D-values show that the combination treatment has more influence on the inactivation of pectinesterase.
Technological Characteristics of Grains from Fourteen Maize Cultivars
Authors: Anselme Kameni , Almeck K. Aboubakar D. , Christiant Kouébou , Marius Jalla Kengne , Charles The , Mbofung Carl MF
Published: July 2007

The effects of cooking and milling of grains from 14 maize cultivars on the characteristics of fine flours were studied in a factorial experimental design. Wet milling significantly increased (P<0.05) fine flour (<400 microns) yields, water absorption capacity at 90°C, solubility index at 25°C, swelling capacity at 95°C and least gel forming concentration. Fine flour composition and functionality were variety dependant. Maize cultivars producing similar fine flours in terms of functionality were classified into three groups: ATP SR-Y, ADV NCRE, CMS 9015, and 88094M131Exp124 for group 1; CMS 8704, CMS 8501, CMS 8806, PDY and ASPY for group 2; and the last group comprising K9351, 87036Exp124, CMS 2019. The specific functional properties maize cultivars should be taken into account in the formulation of pre-cooked weaning food from fine flours.
Finite Element Modeling for Spatial Moisture Content Distribution during Ripening of Camembert Cheese
Authors: Liu Shaowei , Puri Virendra M.
Published: July 2007

Listeria monocytogenes is a food-borne pathogen that can survive and grow during ripening of Camembert, a soft cheese. During the ripening phase, the pH and spatial moisture content continually change, which impacts the growth of Listeria monocytogenes. Development and verification of pH model during ripening phase has been reported already. Therefore, the objective of this study was to develop and verify a moisture content distribution model for the ripening phase of Camembert cheese. A finite element model (FEM) was developed for moisture content distribution during ripening of Camembert cheese. With the initial condition and the boundary conditions, the MATLAB-based FEM was used to calculate the moisture content at six locations: top center (TC), top surface (TS), left center (LC), right center (RC), bottom center (BC), and bottom surface (BS). The FEM showed good agreement with the mean moisture content measured values. The standard error of the predicted moisture content values ranged from 0.0001 to 0.01 g/g. The maximum absolute moisture content difference at six locations during ripening duration was 0.04 g/g. Together, the pH and moisture content models can be integrated with a dynamic predictive growth model to enable the prediction of survival and growth of Listeria monocytogenes during ripening of Camembert cheese.
The Effect of State Cost Containment Strategies on the Insurance Status and Use of Antiretroviral Therapy (HAART) for HIV Infected People
Authors: Ghosh Arkadipta , Sood Neeraj , Leibowitz Arleen
Published: July 2007

In an effort to balance their budgets many states are considering reducing eligibility for Medicaid. Using variation in state policies, this paper models the effect of more stringent eligibility criteria for Medicaid on the insurance status and the use of antiretroviral therapy (HAART) for people living with HIV, a group heavily dependent on Medicaid. Using nationally representative data from the mid-1990's, we find that stricter eligibility thresholds for Medicaid raise uninsurance rates and reduce the use of antiretroviral therapy among HIV+ patients, especially for those who are disabled. These stricter eligibility thresholds in turn adversely affect the survival prospects of HIV+ patients by lowering the rate of HAART use. Our estimates suggest approximately 13,000 lives could have been saved if all states had adopted the eligibility thresholds of California. We do not find any evidence of a "crowding out" effect of public insurance on private coverage among these patients.
Hedge's Ultimate Numerical Technique (HUNT) for Steady State Diffusion Problem
Authors: Hegde Ganesh S , Gattumane Madhu
Published: July 2007

A more realistic numerical technique hereafter known as Hegde's Ultimate Numerical Technique (HUNT) is developed and demonstrated on a one dimensional and a two dimensional steady state diffusion problem of heat transfer. The available numerical methods developed are based on finite difference technique neglecting the contribution of higher order terms in Taylor series expansion of the function leading to an approximation and the error in the solution. In the present effort of the HUNT, the optimization of the partial derivatives leads to the elimination of the error and justifies the stability and the convergence of the solution. The HUNT procedure based on the interface theory developed by the author, is capable of providing the ultimate optimum solution to all the partial derivatives considered as decision vectors. Even though the HUNT is demonstrated on one dimensional and two dimensional steady state diffusion equations, it does not require rigorous efforts to apply it to three dimensional problems of fluid flow and heat transfer. As pilot exercises the HUNT is demonstrated on a one dimensional circular fin and a two dimensional plate to obtain the temperature distribution. The result is compared with the analytical method and the finite volume method for which the results are available in the literature. To the knowledge of the authors, HUNT is both different and a unique example of its kind.
Three-Dimensional Hydrodynamics and Reaction Kinetics Analysis in FCC Riser Reactors
Authors: Novia Novia , S. Ray Martyn , Pareek Vishnu
Published: July 2007

Fluid catalytic cracking (FCC) is the refinery process for the conversion of high molecular-weight hydrocarbons to produce higher valuable products such as gasoline. The optimization of FCC process is challenging due to the complex interactions between a large number of dependent and independent parameters. One of the most uncertain aspects of a fluid catalytic cracking (FCC) unit is the description of fluid-solid mixing at the riser entrance. Most of the existing models assume an instant mixing of solids and gaseous reactants. However, a finite mixing length at the bottom of the riser may have a pronounced effect on the FCC operation, particularly, when very short residence times are allowed in the current commercial FCC risers. A good solid-fluid mixing is essential to ensure a complete feed vaporization which is important for several reasons including assuring a thorough catalyst to oil contact and minimizing coke deposition. In this study, the Eulerian-Eulerian multiphase flow and the 3-lump kinetic models were used to simulate the hydrodynamics and cracking reactions occurring in the FCC riser reactors. The model demonstrated the capability of commercial CFD code FLUENT 6.2 to describe the flow field in the riser reactor. The model also takes into account the temperature, the heat of reactions and gasoline distribution along the riser height.
Editorial: Special Issue Contributed from CHEMECA 2006-Australasian Process Modelling and Control Selected Papers
Authors: Nelson Mark I , Young Brent R
Published: July 2007

The papers in this issue of Chemical Product and Process Modelling are substantially those that arose from special sessions on ``process simulation and control" (organised by Brent R. Young) and ``mathematical modeling" (organised by Mark I. Nelson) at the 34th Australasian Chemical Engineering Conference (held between 17-20th September 2006, in Auckland, New Zealand). The papers in this special issue are available at: http://www.bepress.com/cppm/vol2/iss2. The papers featured in this issue have been revised and extended from CHEMECA and re-reviewed before publication here.All the papers in this issue use mathematics. However, this special issue only features a small number of the presentations at CHEMECA that use mathematics. Mathematics finds many practical applications within chemical engineering and consequently presentations involving mathematics were featured in many special sessions throughout CHEMECA. Some of these presentations will appear in special issues elsewhere. In particular, the papers from every session that were nominated for the John Brodie award are appearing in a special issue of the Asian-Pacific Journal of Chemical Engineering.
Capital Structure and Entry Deterrence with Multiple Incumbents
Authors: Tarzijan Jorge Antonio
Published: July 2007

This paper uses a two-stage Cournot duopoly model with demand uncertainly to examine the strategic role debt plays in deterring a company from entering when a potential entrant can enter one of several markets. We show that as the number of alternative markets available for entry rises, the incumbents' incentive to use debt as a deterrent falls. Thus, a potential entrant will prefer to have a larger number of alternative markets to enter in order to lower the incumbents' incentive to take strategic actions against it.