bluuebunny/crossref_metadata_2025 huggingface dataset:
Is Realist Evaluation a Realistic Approach for Complex Reforms?
Authors: Pedersen Lene Holm , Rieper Olaf
Published: July 2008

The realist evaluation (RE) approach is a promising contribution to the literature on theory-driven evaluation.Thus far, RE has mainly been applied to the evaluation of human service programmes, but the aim of this article is to investigate if it can be extended to large-scale public sector reforms, in casu: the reform of the electricity market in Denmark. Five areas of regulation under the reform were selected and hypotheses on the context, mechanism and outcome (CMO) for each intervention were formulated. The evaluation of three of these interventions is summarized: opening markets to foreign trade, price regulation of monopolies and consumer protection. The article concludes that the CMO framework is applicable not just to interventions at the programme level, but also to large-scale public sector reform characterized by high technical complexity and strong policy coalitions. However, it only serves as a general framework, which has to be substantiated.This is done, first, by generating theories — i.e. programme theories — on each specific intervention. Second, theories are produced at the meso level to identify the institutional patterns that function as conditions for the effects to be obtained.
Habitual Trust in Encountering Violence at Work
Authors: Virkki Tuija
Published: July 2008

• Summary: This article analyses attitudes towards client-perpetrated violence among Finnish social workers and nurses. The research material consists of 25 theme interviews and 20 thematic writings which are examined by means of content analysis.

• Findings: Although statistics show that among all the professional groups in Finland, people working in social welfare and health care are most likely to encounter violence, the risk of violence is underestimated by these professionals. In addition, violence that has taken place is not recognized as `real' violence, but as an excusable expression of clients' distress, or as a justified reaction to the employees' conduct. By using Niklas Luhmann's idea of trust as a way of ignoring risks in spite of being aware of them, the present study shows how trust is at the core of professional activity for caring professions such as those of social workers or nurses. Pierre Bourdieu's concept `habitus', in its part, explains the way in which trusting has became part of a professional orientation which works automatically and seems natural. The study shows that trust orientation is deeply embedded in professional practices, and therefore slow to change.

• Applications : These findings have implications for the prevention of violence: the structural level of the social formation of the habitual trust orientation should be taken into account while the formal policies of prevention are planned.
Gynaecological morbidity among HIV positive pregnant women in Cameroon
Authors: Mbu Enow R , Kongnyuy Eugene J , Mbopi-Keou FX , Tonye Rebecca N , Nana Philip N , Leke Robert JI
Published: July 2008

Objective

To compare the prevalence of gynaecological conditions among HIV infected and non-infected pregnant women.

Methods

Two thousand and eight (2008) pregnant women were screened for HIV, lower genital tract infections and lower genital tract neoplasia at booking antenatal visit.

Results

About 10% (198/2008) were HIV positive. All lower genital tract infections except candidiasis were more prevalent among HIV positive compared to HIV negative women: vaginal candidiasis (36.9% vs 35.4%; p = 0.678), Trichomoniasis (21.2% vs 10.6%; p < 0.001), gonorrhoea (10.1% vs 2.5%; p < 0.001), bacterial vaginosis (21.2% vs 15.2%; p = 0.026), syphilis (35.9% vs 10.6%; p < 0.001), and Chlamydia trachomatis (38.4% vs 7.1%; p < 0.001). Similarly, HIV positive women more likely to have preinvasive cervical lesions: low-grade squamous intraepithelial lesion (SIL) (18.2% vs 4.4%; p < 0.001) and high-grade squamous intraepithelial lesion (12.1% vs 1.5%; p < 0.001).

Conclusion

We conclude that (i) sexually transmitted infections (STIs) are common in both HIV positive and HIV negative pregnant women in Cameroon, and (ii) STIs and preinvasive cervical lesions are more prevalent in HIV-infected pregnant women compared to their non-infected compatriots. We recommend routine screening and treatment of STIs during antenatal care in Cameroon and other countries with similar social profiles.
CSE1L/CAS, the cellular apoptosis susceptibility protein, enhances invasion and metastasis but not proliferation of cancer cells
Authors: Liao Ching-Fong , Luo Shue-Fen , Li Li-Tzu , Lin Chuang-Yu , Chen Ying-Chun , Jiang Ming-Chung
Published: July 2008

Background

The cellular apoptosis susceptibility (CAS) protein is regarded as a proliferation-associated protein that associates with tumour proliferation as it associates with microtubule and functions in the mitotic spindle checkpoint. However, there is no any actual experimental study showing CAS (or CSE1 and CSE1L) can increase the proliferation of cancer cells. Previous pathological study has reported that CAS was strongly positive stained in all of the metastasis melanoma that be examined. Thus, CAS may regulate the invasion and metastasis of cancers. CAS is highly expressed in cancers; if CAS is associated with cancer proliferation, then increased CAS expression should be able to increase the proliferation of cancer cells. We studied whether increased CAS expression can increase cancer cell proliferation and whether CAS regulates the invasion of cancer cells.

Methods

We enhanced or reduced CAS expression by transfecting CAS or anti-CAS expression vectors into human MCF-7 breast cancer cells. The proliferations of cells were determined by trypan blue exclusion assay and flow cytometry analysis. Invasion of cancer cells were determined by matrigel-based invasion assay.

Results

Our studies showed that increased CAS expression was unable to enhance cancer cell proliferation. Immunofluorescence showed CAS was distributed in cytoplasm areas near cell membrane and cell protrusions. CAS was localized in cytoplasmic vesicle and immunogold electronmicroscopy showed CAS was located in vesicle membrane. CAS overexpression enhanced matrix metalloproteinase-2 (MMP-2) secretion and cancer cell invasion. Animal experiments showed CAS reduction inhibited the metastasis of B16-F10 melanoma cells by 56% in C57BL/6 mice.

Conclusion

Our results indicate that CAS increases the invasion but not the proliferation of cancer cells. Thus, CAS plus ECM-degradation proteinases may be used as the markers for predicting the advance of tumour metastasis.
A DNA damage signal activates and derepresses exon inclusion in Drosophila TAF1 alternative splicing
Authors: Marengo Matthew S. , Wassarman David A.
Published: July 2008

Signal-dependent alternative splicing is important for regulating gene expression in eukaryotes, yet our understanding of how signals impact splicing mechanisms is limited. A model to address this issue is alternative splicing of Drosophila TAF1 pre-mRNA in response to camptothecin (CPT)-induced DNA damage signals. CPT treatment of Drosophila S2 cells causes increased inclusion of TAF1 alternative cassette exons 12a and 13a through an ATR signaling pathway. To evaluate the role of TAF1 pre-mRNA sequences in the alternative splicing mechanism, we developed a TAF1 minigene (miniTAF1) and an S2 cell splicing assay that recapitulated key aspects of CPT-induced alternative splicing of endogenous TAF1. Analysis of miniTAF1 indicated that splice site strength underlies independent and distinct mechanisms that control exon 12a and 13a inclusion. Mutation of the exon 13a weak 5′ splice site or weak 3′ splice site to a consensus sequence was sufficient for constitutive exon 13a inclusion. In contrast, mutation of the exon 12a strong 5′ splice site or moderate 3′ splice site to a consensus sequence was only sufficient for constitutive exon 12a inclusion in the presence of CPT-induced signals. Analogous studies of the exon 13 3′ splice site suggest that exon 12a inclusion involves signal-dependent pairing between constitutive and alternative splice sites. Finally, intronic elements identified by evolutionary conservation were necessary for full repression of exon 12a inclusion or full activation of exon 13a inclusion and may be targets of CPT-induced signals. In summary, this work defines the role of sequence elements in the regulation of TAF1 alternative splicing in response to a DNA damage signal.
Structural effects of nucleobase variations at key active site residue Ade38 in the hairpin ribozyme
Authors: MacElrevey Celeste , Salter Jason D. , Krucinska Jolanta , Wedekind Joseph E.
Published: July 2008

The hairpin ribozyme requires functional groups from Ade38 to achieve efficient bond cleavage or ligation. To identify molecular features that contribute to catalysis, structures of position 38 base variants 2,6-diaminopurine (DAP), 2-aminopurine (AP), cytosine (Cyt), and guanine (Gua) were determined between 2.2 and 2.8 Å resolution. For each variant, two substrate modifications were compared: (1) a 2′-O-methyl-substituent at Ade-1 was used in lieu of the nucleophile to mimic the precatalytic state, and (2) a 3′-deoxy-2′,5′-phosphodiester linkage between Ade-1 and Gua+1 was used to mimic a reaction-intermediate conformation. While the global fold of each variant remained intact, the results revealed the importance of Ade38 N1 and N6 groups. Absence of N6 resulting from AP38 coincided with failure to localize the precatalytic scissile phosphate. Cyt38 severely impaired catalysis in a prior study, and its structures here indicated an anti base conformation that sequesters the imino moiety from the scissile bond. Gua38 was shown to be even more deleterious to activity. Although the precatalytic structure was nominally affected, the reaction-intermediate conformation indicated a severe electrostatic clash between the Gua38 keto oxygen and the pro-Rp oxygen of the scissile bond. Overall, position 38 modifications solved in the presence of 2′-OMe Ade-1 deviated from in-line geometry, whereas variants with a 2′,5′ linkage exhibited S-turn destabilization, as well as base conformational changes from syn to anti. These findings demonstrate the importance of the Ade38 Watson–Crick face in attaining a reaction-intermediate state and the sensitivity of the RNA fold to restructuring when electrostatic and shape features fail to complement.
Glucocorticoids antagonize cAMP-induced Star transcription in Leydig cells through the orphan nuclear receptor NR4A1
Authors: Martin Luc J , Tremblay Jacques J
Published: July 2008

It is well established that stress, either physical or psychosocial, causes a decrease in testosterone production by Leydig cells. Glucocorticoids (Gc) are the main mediators of stress response and they convey their repressive effect on Leydig cells through the glucocorticoid receptor (GR). So far, various mechanisms have been proposed to explain the mechanism of action of Gc on Leydig cell steroidogenesis including repression of genes involved in testosterone biosynthesis. Several steroidogenic genes, including steroidogenic acute regulatory (STAR) protein, have been shown to be repressed by Gc in a GR-dependent manner but the underlying mechanisms remain to be fully elucidated. Here, we found that dexamethasone (Dex), a potent synthetic Gc, partly antagonizes the cAMP-dependent stimulation of the mouse Star promoter in MA-10 Leydig cells as revealed by transient transfection assays. This repression requires an element located at −95 bp previously implicated in the activation of the Star promoter by the nuclear receptors, NR4A1 and NR5A1. Dex was found to inhibit NR4A1-dependent transactivation of the Star promoter in Leydig cells by decreasing NR4A1, but not NR5A1, recruitment to the proximal Star promoter as determined by chromatin immunoprecipitation assay. Western blots revealed that Dex did not affect NR4A1 or NR5A1 expression in response to cAMP. These data suggest that NR4A1 would be associated with the GR in a transcriptionally inactive complex as previously demonstrated in pituitary corticotrope cells. Thus, our data provide new molecular insights into the stress-mediated suppression of testosterone production in testicular Leydig cells.
Maternal malnutrition during lactation alters the folliculogenesis and gonadotropins and estrogen isoforms ovarian receptors in the offspring at puberty
Authors: da Silva Faria Tatiane , de Bittencourt Brasil Flávia , Sampaio Francisco J B , da Fonte Ramos Cristiane
Published: July 2008

In this study, we aimed to evaluate whether maternal malnutrition during lactation alters the folliculogenesis and the expression of the gonadotropins and estrogen isoforms ovarian receptors in the offspring at puberty. At parturition, dams were randomly assigned to the following groups: control (C) group, with free access to a standard laboratory diet containing 23% protein and protein-energy-restricted (PER) group, with free access to an isoenergy and protein-restricted diet containing 8% protein. After weaning, the female pups had free access to standard laboratory diet. The maternal malnutrition caused a significant increase in the number of preantral (C=13.72±2.87; PER=26.36±3.03, P<0.01) and small antral follicles (C=9.32±1.35; PER=17.64±2.33, P<0.01) and decrease in the number of primordial (C=11.72±1.37; PER=3.92±0.60, P<0.01) and Graafian follicles (C=1.84±0.21; PER=0.96±0.11, P<0.01), and corpus luteum (C=2.00±0.28; PER=0.80±0.31, P<0.01). The estradiol serum concentration was significantly higher (C=67.86±4.39; PER=83.29±2.68, P<0.05) while testosterone serum concentration did not show statistical difference (C=0.09±0.02; PER=0.11±0.01, P>0.05) in the PER group. In relation to the receptors expression, maternal malnutrition led to a significant increase in the amount of Fshr (C=0.89±0.04; PER=1.07±0.03, P<0.05) and Lhcqr (C=0.87±0.15; PER=1.33±0.08, P<0.05) transcripts and a significant decrease in the amount of Ar (C=0.59±0.006; PER=0.13±0.080, P<0.05), ERα (Esr1) (C=3.33±0.71; PER=0.74±0.50, P<0.05), ERβ1 (Esr2) (C=1.33±0.06; PER=0.49±0.36, P<0.05), and ERβ2 (Esr2) (C=3.28±0.60; PER=0.62±0.34, P<0.05) transcripts. In conclusion, perinatal maternal malnutrition can directly affect folliculogenesis at puberty probably as a consequence of changes in the ovarian expression of gonadotropins, androgen and estrogens isoforms receptors. Long-term sexual alterations could be expected in this experimental model, since a reduction in the primordial follicle number is observed, which can result in a decrease in the reproductive lifetime and an earlier termination of breeding capacity.
Analytical Solution of Nonisothermal Buckley-Leverett Flow Including Tracers
Authors: Sumnu-Dindoruk Deniz , Dindoruk Birol
Published: July 2008

Mass balances for two immiscible fluids and tracer and convective heat balance form a system of three equations (nonisothermal Buckley-Leverett Problem with tracers). Tracer component is considered to investigate the propagation of a tracer to track the flood (or to track a miscible inert contaminant introduced during drilling). We have solved the resulting nonisothermal two-phase convective flow equation in porous media analytically, including a tracer component (i.e., cold or hot waterflooding with and without tracer). Method of characteristics (MOC) is used as a solution technique after transforming the balance equations in a form that can be solved easily with two Welge tangents. Our solution technique is valid for both radial-and linear-flow models.

In practice, these solutions can be used

To investigate the convective flow behavior around the wells (i.e., sudden fluid losses, convective near-well tracer propagation, analyzing pressure transients). To interpret formation-testing-tool responses by detecting the location of the thermal front or to estimate the temperature-buildup time that is needed for Horner-type analysis (for the identification of the formation temperature). To calculate the location of the cold or hot water front (thermal water) while injecting cold-or hot-water. This will yield the limit of the maximum temperature disturbance around the well. To test/scale relative thermal effects of various systems against one another. To test the accuracy of simulators and provide benchmark solutions. To interpret relevant laboratory experiments quickly.

Such solutions helped us to understand the depth of influence of the temperature variations and their influence on the transport properties, in both radial and linear systems. Solutions analytically proved that the thermal front propagates much slower than the flood front. This explains why isothermal black-oil simulators still work although the injected-water temperature is not always equal to the reservoir temperature.

Furthermore, we have checked and verified our results against a commercial thermal simulator and investigated the impact of numerical diffusion on the thermal front as well as conductivity. This part of the work revealed that the temperature front is more prone to numerical diffusion.
The Application of Artificial Neural Networks With Small Data Sets: An Example for Analysis of Fracture Spacing in the Lisburne Formation, Northeastern Alaska
Authors: Kaviani D. , Bui T. D. , Jensen J. L. , Hanks C. L.
Published: July 2008

Artificial neural networks (ANNs) have been used widely for prediction and classification problems. In particular, many methods for building ANNs have appeared in the last 2 decades. One of the continuing important limitations of using ANNs, however, is their poor ability to analyze small data sets because of overfitting. Several methods have been proposed in the literature to overcome this problem. On the basis of our study, we can conclude that ANNs that use radial basis functions (RBFs) can decrease the error of the prediction effectively when there is an underlying relationship between the variables. We have applied this and other methods to determine the factors controlling and related to fracture spacing in the Lisburne formation, northeastern Alaska.

By comparing the RBF results with those from other ANN methods, we find that the former method gives a substantially smaller error than many of the alternative methods. For example, the errors in predicted fracture spacing for the Lisburne formation with conventional ANN methods are approximately 50 to 200% larger than those obtained with RBFs. With a method that predicts fracture spacing more accurately, we were able to identify more reliably the effects on the spacing of such factors as bed thickness, lithology, structural position, and degree of folding.

By comparing performances of all the methods we tested, we observed that some methods that performed well in one test did not necessarily do as well in another test. This suggests that, while RBF can be expected to be among the best methods, there is no "best universal method" for all the cases, and testing different methods for each case is required. Nonetheless, through this study, we were able to identify several candidate methods and, thereby, narrow the work required to find a suitable ANN.

In petroleum engineering and geosciences, the number of data is limited in many cases because of expense or logistical limitations (e.g., limited core, poor borehole conditions, or restricted logging suites). Thus, the methods used in this study should be attractive in many petroleum-engineering contexts in which complex, nonlinear relationships need to be modeled by use of small data sets.
Decline-Curve Analysis of Fractured Reservoirs With Fractal Geometry
Authors: Camacho Velázquez Rodolfo , Fuentes-Cruz Gorgonio , Vásquez-Cruz Mario
Published: July 2008

Evaluation of reservoir parameters through well-test and decline-curve analysis is a current practice used to estimate formation parameters and to forecast production decline identifying different flow regimes, respectively. From practical experience, it has been observed that certain cases exhibit different wellbore pressure and production behavior from those presented in previous studies. The reason for this difference is not understood completely, but it can be found in the distribution of fractures within a naturally fractured reservoir (NFR). Currently, most of these reservoirs are studied by means of Euclidean models, which implicitly assume a uniform distribution of fractures and that all fractures are interconnected. However, evidence from outcrops, well logging, production-behavior studies, and the dynamic behavior observed in these systems, in general, indicate the above assumptions are not representative of these systems. Fractal theory considers a nonuniform distribution of fractures and the presence of fractures at different scales; thus, it can contribute to explain the behavior of many fractured reservoirs. The objective of this paper is to investigate the production-decline behavior in an NFR exhibiting single and double porosity with fractal networks of fractures. The diffusion equations used in this work are a fractal-continuity expressions presented in previous studies in the literature and a more recent generalization of these equations, which includes a temporal fractional derivative. The second objective is to present a combined analysis methodology, which uses transient-well-test and bound-ary-dominated-decline production data to characterize an NFR exhibiting fractures, depending on scale. Several analytical solutions for different diffusion equations in fractal systems are presented in Laplace space for both constant-wellbore-pressure and pressure-variable-rate inner-boundary conditions. Both single- and dual-porosity systems are considered. For the case of single-porosity reservoirs, analytical solutions for different diffusion equations in fractal systems are presented. For the dual-porosity case, an approximate analytical solution, which uses a pseudosteady-state matrix-to-fractal fracture-transfer function, is introduced. This solution is compared with a finite-difference solution, and good agreement is found for both rate and cumulative production. Short- and long-time approximations are used to obtain practical procedures in time for determining some fractal parameters. Thus, this paper demonstrates the importance of analyzing both transient and boundary-dominated flow-rate data for a single-well situation to fully characterize an NFR exhibiting fractal geometry.

Synthetic and field examples are presented to illustrate the methodology proposed in this work and to demonstrate that the fractal formulation consistently explains the peculiar behavior observed in some real production-decline curves.
Toward Field-Scale Wettability Modification—The Limitations of Diffusive Transport
Authors: Stoll W. M. , Hofman J. P. , Ligthelm D. J. , Faber M. J. , van den Hoek P. J.
Published: July 2008

Densely-fractured oil-wet carbonate fields pose a true challenge for oil recovery that traditional primary and secondary processes fail to meet. The difficulty arises from the combination of two unfavorable characteristics: First, the dense fracturing frustrates an efficient waterflood; second, because of the oil-wetness, the water pressure exceeds the oil pressure inside the matrix blocks, thus inhibiting spontaneous imbibition of water. In the past decade, using a new class of surfactants, enhanced oil recovery (EOR) researchers have studied the options to chemically revert the wettability of carbonate rock without drastically decreasing the oil-water interfacial tension. These chemicals, termed "wettability modifiers" (WMs), effectively reverse the sign of capillary pressure at the prevalent saturation. With the oil pressure exceeding the water pressure, the capillary pressure becomes the driving force for oil expulsion from the matrix and into the fracture system.

Previous publications on chemical wettability modification focused on the performance of different chemical wettability modifiers for a chosen rock/oil/brine system. In some cases, they demonstrated an almost full oil recovery from core plugs. Little attention, however, has been given to the mechanism underlying the transport of the chemical into the matrix block and to the proper scaling of laboratory results to reservoir size. The present study aims to demonstrate that imbibition after wettability modification is diffusion-limited. To this end, the recovery profiles for spontaneous capillary imbibition, as well as for imbibition after wettability modification, are calculated. The results are then used to compare with the data of Amott cell imbibition experiments. It is confirmed that in both cases, the cumulative recovery is initially proportional to the square root of time. Imbibition after wettability modification, however, takes approximately 1,000 times longer than spontaneous capillary imbibition into a water-wet medium. The slow recovery observed in the case of imbibition after wettability modification is in excellent agreement with the assumption that, in the absence of significant spontaneous imbibition, the WM, to unfold its action, must first diffuse into the porous medium. In any diffusion process, the time scale is linked to the square of the length scale of the medium. Therefore, it would take up to 1,000 times longer (an equivalent of 200 years) before the same recovery is obtained from a meter-scale matrix block as is obtained from a centimeter-scale plug in a laboratory in 100 days.

Consequently, unless a significantly faster transport mechanism for the wettability modifier is identified, or unless viscous forces or buoyancy enable forced imbibition, the chemical wettability modification of fractured oil-wet carbonate rock does not provide an economically interesting opportunity.
Characterization of Crosslinked Gel Kinetics and Gel Strength by Use of NMR
Authors: Romero-Zerón L. , Manalo F. , Kantzas A.
Published: July 2008

Highly crosslinked gels are used in high-permeability reservoirs to achieve appropriate fluid-loss control during well completion and workover operations. Crosslinked gels are also used to shut off unwanted gas and/or water influx into production wells and to improve the conformance of the near-wellbore injection profile in naturally fractured or high-permeability reservoirs. In all these applications, the appropriate design of the gel treatment is critical to ensure an efficient gel placement. Important variables of gel systems are gel rheology and gel strength during and after the gelation reaction is completed.

The rheology of gels and gelation rates is commonly determined by rheometry or, in a qualitative mode, through bottle testing with well-known gel-strength codes (i.e., Sydansk's code). Rheological measurements can be time-consuming, while bottle testing can lead to an inconsistent gel description as a result of the subjective nature of the gel-strength code. This paper evaluates the use of low-field nuclear magnetic resonance (NMR) as a nonin-trusive technique to monitor gelation rates and to characterize gel strength. Because of the nonintrusive nature of this technique, it could be considered to be a better alternative to conventional rhe-ological measurements and common qualitative methods, such as gel-strength codes. In addition, NMR could offer faster and more accurate gel-strength characterization and gelation monitoring compared to rheological methods. Furthermore, it can be used in porous media. NMR parameters are predicted and calibrated conducting concentration sweeps of polymer, crosslinker, and brine, as well as gelation-time sweeps. This then allows for a standardized method for gel characterization.

The findings of this work include a preliminary assessment of the use of different techniques, such as low-field NMR, rheometry, and bottle testing, for monitoring the gelation reaction and gel strength of partially hydrolyzed polyacrylamide chromium [(HPAm)/Cr(III)] acetate gel. The experimental results also include the initial identification of the gel point for different formulations of the gel system using low-field NMR.
Estimation of Near-Wellbore Alteration and Formation Stress Parameters From Borehole Sonic Data
Authors: Sinha Bikash , Bratton Tom , Cryer Jesse , Nieting Steve , Ugueto Gustavo , Bakulin Andrey , Hauser Matt
Published: July 2008

Highly depleted reservoirs exhibit sharply lower pore pressures and horizontal stress magnitudes than does the overlying shaly formation. Drilling through such depleted reservoirs can cause severe fluid loss and drilling-induced wellbore instability. Accurate and reliable estimates of horizontal stresses can provide an early warning of impending drilling problems that may be mitigated by appropriate drilling fluid design and drilling practices. We have developed a new multifrequency inversion algorithm for the estimation of maximum and minimum horizontal stress magnitudes using cross-dipole dispersions. Borehole sonic data for the case study presented in this paper was acquired by a cross-dipole sonic tool in a deepwater well, offshore Louisiana in the Gulf of Mexico (GOM). The logged interval spans 1,000 ft below the casing shoe. In addition, the Modular Dynamic Tester (MDT) (©Schlumberger) minifrac tests were performed at three depths in shale, thus yielding two minimum horizontal stress magnitudes. The borehole sonic data were suitable for the inversion of crossdipole dispersions at three depths in shale, as well as at a depth in a highly depleted sand reservoir. There was one depth in shale above the depleted sand where we could estimate the minimum horizontal stress magnitude with both the MDT minifrac tests and inversion of borehole sonic data. The results of the two techniques are consistent, providing encouragement for further validation of the multifrequency inversion of cross-dipole dispersions to estimate horizontal stresses. Even though the overburden stress is expected to increase with depth, both the maximum (SHmax) and minimum (Shmin) horizontal stresses obtained from the inversion of borehole sonic data are significantly smaller in the depleted sand than in the overburden shale. However, both the horizontal stress magnitudes increase again in the shale below the depleted sand. Such rapid variations in horizontal stress magnitudes cause large fluctuations in the safe mud-weight window. This challenge in drilling through the depleted sand was successfully handled by using special drilling fluid to mitigate seepage losses and the differential sticking in the depleted sand and overlying shale. We have also performed dipole radial profiling (DRP) of formation shear slownesses using the measured cross-dipole dispersions at three depths in shale and one in highly depleted sand. Analysis of radial profiles in the two orthogonal directions indicates plastic yielding or stiffening of rock in the near-wellbore region. While plastic yielding increases the shear slowness, stiffening would reduce the shear slowness.
Environmental assessment and cost estimation of drinking water and wastewater systems for transition areas in Sweden
Authors: Norström A. , Erlandsson Å. , Kärrman E.
Published: July 2008

In the Stockholm region there are around 90,000 households with single systems. These households cause larger phosphorus flows to the Baltic Sea than the 1.8 million people connected to four advanced large-scale treatment plants in the same region. According to city plans, some of these areas with on-site systems in transition to permanent living shall be connected to central systems. The problem is however that this sewer system will take decades to complete. It is also not ensured whether or not all peripheral areas with on-site systems could be connected to the central systems. To help support environmental decisions for the selection of wastewater systems for these areas, an Excel-based model has been developed where the cost for the systems can be assessed and evaluated in relation to their environmental impact. The model deals with two types of environmental issues: substance flow analysis and energy analysis. The cost part considers investigations, investments, design, operation, maintenance and supervision, and calculates total annual cost for the water and wastewater system per person.
The efficiency of biological aerobic treatment of piggery wastewater to control nitrogen, phosphorus, pathogen and gas emissions
Authors: Béline F. , Daumer M. L. , Loyon L. , Pourcher A. M. , Dabert P. , Guiziou F. , Peu P.
Published: July 2008

Due to the water pollution and in order to reduce the nitrogen load applied on soils, biological nitrogen removal treatment of piggery wastewaters was developed in Brittany (France), with 250–300 units running. Four types of treatment processes were built including a biological reactor allowing to remove about 60–70% of the nitrogen content as gas by nitrification/denitrification. The addition of different mechanical separators (screw-press, centrifuge decanter …) led to concentration of phosphorus in an exportable solid phase, allowing a reduction up to 80% of the phosphorus applied locally on soils. Moreover, a reduction of the gaseous emissions was observed using this management process as compared to conventional management (storage + land spreading) including ammonia (up to 68%) and greenhouse gases (55%). Finally, the level of enteric and pathogenic bacteria was also decreased with the treatment process as compared to conventional management systems. However, in spite of these results, the significant cost of the treatment must be underlined and alternative systems including anaerobic digestion will have to be studied.
A two-stage subsurface vertical flow constructed wetland for high-rate nitrogen removal
Authors: Langergraber Guenter , Leroch Klaus , Pressl Alexander , Rohrhofer Roland , Haberl Raimund
Published: July 2008

By using a two-stage constructed wetland (CW) system operated with an organic load of 40 g COD·m−2·d−1 (2 m2 per person equivalent) average nitrogen removal efficiencies of about 50% and average nitrogen elimination rates of 980 g N·m−2·yr−1 could be achieved. Two vertical flow beds with intermittent loading have been operated in series. The first stage uses sand with a grain size of 2–3.2 mm for the main layer and has a drainage layer that is impounded; the second stage sand with a grain size of 0.06–4 mm and a drainage layer with free drainage. The high nitrogen removal can be achieved without recirculation thus it is possible to operate the two-stage CW system without energy input. The paper shows performance data for the two-stage CW system regarding removal of organic matter and nitrogen for the two year operating period of the system. Additionally, its efficiency is compared with the efficiency of a single-stage vertical flow CW system designed and operated according to the Austrian design standards with 4 m2 per person equivalent. The comparison shows that a higher effluent quality could be reached with the two-stage system although the two-stage CW system is operated with the double organic load or half the specific surface area requirement, respectively. Another advantage is that the specific investment costs of the two-stage CW system amount to 1,200 EUR per person (without mechanical pre-treatment) and are only about 60% of the specific investment costs of the singe-stage CW system.
An insight into cathode options for microbial fuel cells
Authors: Lefebvre O. , Al-Mamun A. , Ooi W. K. , Tang Z. , Chua D. H. C. , Ng H. Y.
Published: July 2008

Microbial fuel cell (MFC) is an emerging and promising technology, particularly in the field of wastewater treatment. The MFC capability of achieving organic removal and generating in situ electricity could make it an attractive alternative wastewater treatment technology over conventional treatment technologies. However, MFC is still far from being economically viable, especially because of the cost of the platinum (Pt) catalyst that makes possible the reaction at the cathode. In this study, we tested alternative cathode catalysts, namely sputter-deposited Cobalt (Co) and denitrifying bacteria (biocathode). The performance of these innovative cathodes was compared with that of classic Pt-cathodes. Co competed well with Pt, but further research is still required for biocathodes. However, biocathodes MFC have showed promise.
Application of metaproteomic analysis for studying extracellular polymeric substances (EPS) in activated sludge flocs and their fate in sludge digestion
Authors: Park C. , Helm R. F.
Published: July 2008

Metaproteomic analysis, comprising protein separation and identification, was applied to study extracellular proteins in activated sludges and to track their fate in sludge digestion under both anaerobic and aerobic conditions. The complex sludge proteins were first separated by sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE) and further analysed by liquid chromatography tandem mass spectrometry (LC-MS/MS) to search their identification. Base extraction and cation exchange resin (CER) method were used to extract EPS from sludges at 0, 12 and 30 days of batch digestion. Several important observations were made during this study. Firstly, protein bands were well separated by extraction/SDS-PAGE protocol used in this study. Secondly, numerous protein bands remained after digestion, indicating that these proteins are not easily degradable in sludge digestion. Thirdly, protein bands detected following anaerobic and aerobic digestion differed, suggesting that proteins degraded in two different digestion environments are not the same. Finally, protein bands that emerged distinctively following anaerobic digestion was found to be subunits of methyl-coenzyme M reductase, the enzyme involved in methane generation, in Methanosarcina barkeri. These results demonstrated that metaproteomic investigation on activated sludge EPS is useful for studying floc formation in activated sludges and their degradation in various digestion environments.
Analysis of nitrifying bacterial communities in aerobic biofilm reactors with different DO conditions using molecular techniques
Authors: Park J. J. , Byun I. G. , Yu J. C. , Park S. R. , Ju D. J. , Hur S. H. , Park T. J.
Published: July 2008

In order to assess the relationship between the dissolved oxygen (DO) concentration and the characteristics of nitrifying bacterial communities in an aerobic biofilm reactor, molecular techniques including denaturing gradient gel electrophoresis (DGGE)/cloning based on PCR targeting 16S rRNA and the amoA gene and fluorescence in situ hybridisation (FISH) were conducted. The D-1, D-2, D-3 and D-4 reactors with different DO concentrations (1, 3, 5 and 7 mg/L, respectively) were set up in the thermostat and acclimated. The optimal DO concentration with stable nitrification efficiency was above 5.0 mg/L. As was shown by the results of DGGE and cloning, the community of ammonia-oxidising bacteria (AOB) and the ratio of Nitrosomonas sp. changed only slightly despite their differing nitrification efficiencies. The results of FISH indicated that higher DO concentrations resulted in an increase in AOB and nitrite-oxidising bacteria (NOB), and a reduction in heterotrophic microorganisms. The INT-dehydrogenase activity (DHA) test demonstrated that the activity of AOB decreased with reductions in the DO concentration. This means that the DO concentration does not influence the community of AOB, but rather the activity of AOB. In the relationship between the attached biomass and the nitrification efficiency, only the active biomass affected the nitrification efficiencies.
Evaluation of Live‐Capture Techniques for Free‐Ranging Wolverines
Authors: LOFROTH ERIC C. , KLAFKI RICHARD , KREBS JOHN A. , LEWIS DAVE
Published: July 2008

Abstract: Wolverines (Gulo gulo) are a rare carnivore and live‐capture efforts often comprise a significant component of field research projects. Wolverine studies have used aerial, snowmobile, hand‐capture, and live‐trap capture techniques. We reviewed existing wolverine live‐capture data to evaluate sex‐related biases associated with capture technique. We modified round log live traps, developed a new portable wooden live trap, and evaluated effects of live trap type, trap‐site selection, and seasonal timing of trapping on wolverine capture success. Aerial capture techniques had a positive bias for capture of male wolverines. Live‐capture rates were highest for portable wooden traps and lowest for barrel traps. Trapping success was highest during March when snow conditions were amenable to wolverine travel and temperatures improved bait effectiveness. Traps in corridor habitats were more successful than traps in noncorridor habitats. This difference was more pronounced in environments with rugged topography. We provide guidance for live‐trap operation, describe animal handling procedures, and provide detailed instructions for construction of modified round log and portable wooden wolverine live traps. These will benefit future wolverine studies by increasing trap effectiveness and reducing risk of injury and mortality to captured wolverines.
Puma and Human Spatial and Temporal Use of a Popular California State Park
Authors: SWEANOR LINDA L. , LOGAN KENNETH A. , BAUER JIM W. , MILLSAP BLUE , BOYCE WALTER M.
Published: July 2008

Abstract: Because of increasing concerns about puma (Puma concolor) attacks on people and the desire to minimize dangerous puma‐human encounters while conserving puma populations, we examined spatial and temporal relationships between pumas and people that used Cuyamaca Rancho State Park (CRSP), California, USA. From 2001 to 2003, we studied 10 adult pumas outfitted with Global Positioning System collars. Although number of visitors to CRSP was increasing, no dangerous puma‐human encounters were reported during our study. Male and female pumas typically moved short distances during the day (mean of means of individual hourly movements = 168 m and 131 m each hr, respectively) and moved the most at night (mean of means = 690 m and 390 m each hr, respectively). Of 10 pumas, 9 were least active during the day and most active during the evening or at night. In contrast, most visitor use of trails (x̄ = 85%) occurred during the day. Based on puma and human activity patterns, risk of a puma‐human encounter was greatest during the evening. Puma prey caches were randomly distributed in relation to trails and park facilities; however, 8 of 33 caches were still within 100 m of a trail and 2 were within 300 m of a facility. Individual puma behavior relative to human activity areas was variable. Some pumas appeared to temporally avoid human activity areas; others used the park randomly in relation to human activity areas; none appeared to be attracted to human activity areas. Pumas that did not show detectable responses to human activity may have been exhibiting some level of habituation; if so, this level of habituation did not result in puma‐human conflicts. When human activity peaked during the day, adult male and female pumas were within 100 m of a trail an average of 9% and 19% of the time they were located in the park, respectively. Thus, there were opportunities for puma‐human encounters. Management personnel can take a proactive approach to deal with puma‐human interactions through education and protocols that help to minimize probability of conflicts; this may provide the best chance for a continued puma presence in habitat used by pumas and people.
Evaluating Dependence Among Mule Deer Siblings in Fetal and Neonatal Survival Analyses
Authors: BISHOP CHAD J. , WHITE GARY C. , LUKACS PAUL M.
Published: July 2008

Abstract: The assumption of independent sample units is potentially violated in survival analyses where siblings comprise a high proportion of the sample. Violation of the independence assumption causes sample data to be overdispersed relative to a binomial model, which leads to underestimates of sampling variances. A variance inflation factor, c, is therefore required to obtain appropriate estimates of variances. We evaluated overdispersion in fetal and neonatal mule deer (Odocoileus hemionus) datasets where more than half of the sample units were comprised of siblings. We developed a likelihood function for estimating fetal survival when the fates of some fetuses are unknown, and we used several variations of the binomial model to estimate neonatal survival. We compared theoretical variance estimates obtained from these analyses with empirical variance estimates obtained from data‐bootstrap analyses to estimate the overdispersion parameter, c. Our estimates of c for fetal survival ranged from 0.678 to 1.118, which indicate little to no evidence of overdispersion. For neonatal survival, 3 different models indicated that ĉ ranged from 1.1 to 1.4 and averaged 1.24–1.26, providing evidence of limited overdispersion (i.e., limited sibling dependence). Our results indicate that fates of sibling mule deer fetuses and neonates may often be independent even though they have the same dam. Predation tends to act independently on sibling neonates because of dam‐neonate behavioral adaptations. The effect of maternal characteristics on sibling fate dependence is less straightforward and may vary by circumstance. We recommend that future neonatal survival studies incorporate additional sampling intensity to accommodate modest overdispersion (i.e., ĉ = 1.25), which would facilitate a corresponding ĉ adjustment in a model selection analysis using quasi‐likelihood without a reduction in power. Our computational approach could be used to evaluate sample unit dependence in other studies where fates of individually marked siblings are monitored.
Formation of All-Carbon Quaternary Centers by Copper-Catalyzed Asymmetric Conjugate Addition
Authors: Alexakis Alexandre , Vuagnoux-d'Augustin Magali , Martin David , Kehrli Stefan , Palais Laetitia , Hénon Hélène , Hawner Christine
Published: July 2008

This mini-review deals with a special, and challenging, aspect of the asymmetric conjugate addition: the formation of all-carbon quaternary centers by reaction with Michael acceptors bearing a polysubstituted unsaturation. Only copper catalysts allow this transformation, along with
a careful choice of primary organometallics and chiral ligand. The resulting adducts are useful intermediates for the synthesis of more complex natural products.
Expression and Amplification of Chirality in Two-Dimensional Molecular Crystals
Authors: Ernst Karl-Heinz
Published: July 2008

Chirality can be bestowed onto achiral surfaces by adsorption of chiral molecules. This offers a good opportunity to study two-dimensional chiral crystallization phenomena, like lateral resolution of enantiomers or the transfer of handedness from single molecules into mesoscopic ensembles
with high resolution by scanning probe microscopy. Induction of homochirality on surfaces via cooperatively amplified interactions in molecular monolayers is a new phenomenon of supramolecular surface chirality. Prochiral molecules will turn into either handedness upon adsorption, but
doping with intrinsically chiral molecules breaks this symmetry and induces homochirality. A similar effect is induced by a small enantiomeric excess. The excess molecules provide the chiral bias that becomes amplified into single lattice chirality.
New Practical Synthesis of the Exceptional Musk Odorants (R)-Muscone and (R,Z)-5-Muscenone
Authors: Knopff Oliver , Kuhne Jérôme
Published: July 2008

Herein we describe a short and practical synthesis of the exceptional musk odorants (R)-muscone and (R,Z)-5-muscenone from a readily available achiral macrocyclic diketone. The key step of the synthesis is the first sodium N-methylephedrate mediated enantioselective
aldol condensation reaction (up to 76% ee). This new type of reaction proceeds via a dynamic kinetic resolution of an aldol intermediate.
Inducing Helical Chirality by Deforming Hexanuclear Metalloprismatic Structures
Authors: Therrien Bruno , Süss-Fink Georg
Published: July 2008

A comparative structural study of eleven empty and eight filled hexanuclear metalloprismatic cages reveals helical chirality depending on the twist angle between the upper and lower triangles defined by three metal centres.