bluuebunny/crossref_metadata_2025 huggingface dataset:
General Fund Financing, Earmarking, Economic Stabilization, and Welfare
Authors: Chen Been-Lon , Lee Shun-Fa
Published: February 2009

Discussion has been made concerning the pros and cons of financing public projects via either earmarking or a general fund. The article studies the desirability of earmarked and general fund financing based on economic stabilization in a two-sector growth model. Regardless of the nature of public goods, earmarked taxes contribute to aggregate stabilization, while general fund financing may be destabilizing and cause fluctuations. The underlying mechanism in favor of earmarked taxes against general fund financing is that general fund financing creates intersectoral externalities and strategic complementarities that are sufficiently large to exert endogenously persistent and recurring fluctuations in aggregate activities in the absence of shocks to fundamentals. Earmarked taxing generates only sector-specific externalities that are too small to exert local indeterminacy. In a calibrated version, we compute the level of long-run welfare, and the results reflect favorably on the use of earmarked taxing.
Private pleasures
Authors: Pertierra Anna Cristina
Published: February 2009

This article traces circuits of distribution and consumption of videocassette recorders (VCRs) and videocassettes in Cuba, which until April 2008 were not available for retail sale, and were usually sourced through black market or informal means. Based upon ethnographic research conducted in 2003/4 with VCR owners and an operator of an informal videocassette rental business, the article argues that understanding the role of video in contemporary Cuba requires a consideration of both the political and economic implications of being a video consumer and the material properties of VCRs as consumer goods. In the context of post-Soviet Cuba, VCRs and videocassettes exemplify the importance of informal practices and economies, and call attention to increased tensions surrounding consumption that have developed since the economic crisis of the 1990s.
Poverty as danger
Authors: Taylor Erin B.
Published: February 2009

Poor urban communities throughout Latin America and the Caribbean have been historically represented as sites of physical and moral danger. In recent years they have been blamed in particular for causing a surge in urban crime. This article explores how such representations are constructed through a process of engagement between many sectors of society. I examine how the general public, the national media and a poor barrio in Santo Domingo (Dominican Republic) contribute to a discourse that spatializes poverty and crime. I argue that the poor are the victims of a class politics that is played out on designated urban spaces in which they symbolize the economic and political crises of the state and middle-class fears of loss of social status. By marginalizing the poor to bounded, powerless spaces, the middle class retain their moral right to respectability and the possibility of social ascendance.
A smooth transition?
Authors: Barron Paul , D'Annunzio-Green Norma
Published: February 2009

While the most common type of student entering higher education falls within the 17—19-year-old age group, universities in the UK are keen to accept other categories of students onto programmes as a means of increasing diversity and maintaining student numbers in the latter portion of a programme. One such category is those students who enter a programme directly into the second or third year through informal articulation agreements between institutions and the recognition and granting of credit for previous studies or experience. This article examines the expectations of a cohort of students entering directly into the second and third year of an undergraduate degree in the business school of a Scottish university. This study identified a range of learning, personal and working issues amongst this group of students. Academic concerns included the ability to cope with a higher academic level, time management, assessments and study skills. Personal issues focused on coping with existing responsibilities and achieving an appropriate work/life balance. This article identifies the need to develop such students' academic self-confidence in the early stages of their time at university and indicates that this group of students has specific needs and requires additional institutional support.
Students pay attention!
Authors: Young Mark S. , Robinson Stephanie , Alberts Phil
Published: February 2009

Maintaining student concentration in lectures has long been a challenge for lecturers. Pedagogical research consistently finds a drop in attention between 10 and 30 minutes into the lecture, which has been associated with the passive nature of the standard format, and has consequences for learning approaches and outcomes. A similar phenomenon has been observed in ergonomics for some time, known as the vigilance decrement. In this article, we present an exploratory effort to detect the vigilance decrement in four different lecture formats, by adopting an ergonomics measurement tool which has been related to vigilance, and relating the findings to students' assessment results. It was found that standard lecture formats do induce a vigilance decrement, and this can adversely affect learning of the material. Conversely, vigilance degradation is avoided when presentation is varied, though this is not necessarily associated with interactive participation techniques. Implications for lecturing styles, learning approaches and pedagogical research methods are discussed.
Interfacial reaction and mechanical reliability of eutectic Sn–0·7Cu/immersion Ag-plated Cu solder joint
Authors: Yoon J.-W. , Jung S.-B.
Published: February 2009

In this study, the interfacial reaction and joint reliability of immersion Ag-plated Cu substrate with the Sn–0·7Cu (wt-%) ball–grid array (BGA) solder was investigated. During reflow, the Ag plating layer was dissolved completely into the molten Sn–Cu solder and some of the Cu layer was also dissolved into the molten solder. The dissolved Ag and Cu were precipitated as Ag3Sn and Cu6Sn5 intermetallic compounds (IMCs) in the solder matrix. Upon reflow, the Sn–Cu solder exhibits an off-eutectic reaction to produce the eutectic phase and precipitate (Cu6Sn5 and Ag3Sn). The Cu–Sn IMC layer was formed at the solder/Cu interface after reflow, and the IMC layer grew during aging treatment. During the shear tests, the failure mode switched from a bulk-related failure to an interface-related failure. After aging for 250 h, the joint failed partially at the solder/Cu6Sn5 interface. The brittle fracture was linked to the formation of thick Cu–Sn IMC layer.
Stage 3 immature human natural killer cells found in secondary lymphoid tissue constitutively and selectively express the TH17 cytokine interleukin-22
Authors: Hughes Tiffany , Becknell Brian , McClory Susan , Briercheck Edward , Freud Aharon G. , Zhang Xiaoli , Mao Hsiaoyin , Nuovo Gerard , Yu Jianhua , Caligiuri Michael A.
Published: February 2009

Considerable functional heterogeneity within human natural killer (NK) cells has been revealed through the characterization of distinct NK-cell subsets. Accordingly, a small subset of CD56+NKp44+NK cells, termed NK-22 cells, was recently described within secondary lymphoid tissue (SLT) as IL-22− when resting, with a minor fraction of this population becoming IL-22+ when activated. Here we discover that the vast majority of stage 3 immature NK (iNK) cells in SLT constitutively and selectively express IL-22, a TH17 cytokine important for mucosal immunity, whereas earlier and later stages of NK developmental intermediates do not express IL-22. These iNK cells have a surface phenotype of CD34−CD117+CD161+CD94−, largely lack expression of NKp44 and CD56, and do not produce IFN-γ or possess cytolytic activity. In summary, stage 3 iNK cells are highly enriched for IL-22 and IL-26 messenger RNA, and IL-22 protein production, but do not express IL-17A or IL-17F.
Binding of PFOS to serum albumin and DNA: insight into the molecular toxicity of perfluorochemicals
Authors: Zhang Xian , Chen Ling , Fei Xun-Chang , Ma Yin-Sheng , Gao Hong-Wen
Published: February 2009

Background

Health risk from exposure of perfluorochemicals (PFCs) to wildlife and human has been a subject of great interest for understanding their molecular mechanism of toxicity. Although much work has been done, the toxigenicity of PFCs remains largely unknown. In this work, the non-covalent interactions between perfluorooctane sulfonate (PFOS) and serum albumin (SA) and DNA were investigated under normal physiological conditions, aiming to elucidate the toxigenicity of PFCs.

Results

In equilibrium dialysis assay, the bindings of PFOS to SA correspond to the Langmuir isothermal model with two-step sequence model. The saturation binding number of PFOS was 45 per molecule of SA and 1 per three base-pairs of DNA, respectively. ITC results showed that all the interactions were spontaneous driven by entropy change. Static quenching of the fluorescence of SA was observed when interacting with PFOS, indicating PFOS bound Trp residue of SA. CD spectra of SA and DNA changed obviously in the presence of PFOS. At normal physiological conditions, 1.2 mmol/l PFOS reduces the binding ratio of Vitamin B2 to SA by more than 30%.

Conclusion

The ion bond, van der Waals force and hydrophobic interaction contributed to PFOS binding to peptide chain of SA and to the groove bases of DNA duplex. The non-covalent interactions of PFOS with SA and DNA alter their secondary conformations, with the physiological function of SA to transport Vitamin B2 being inhibited consequently. This work provides a useful experimental method for further studying the toxigenicity of PFCs.
Unambiguous molecular detections with multiple genetic approach for the complicated chromosome 22q11 deletion syndrome
Authors: Yang Chen , Huang Cheng-Hung , Cheong Mei-Leng , Hung Kun-Long , Lin Lung-Huang , Yu Yeong-Seng , Chien Chih-Cheng , Huang Huei-Chen , Chen Chan-Wei , Huang Chi-Jung
Published: February 2009

Background

Chromosome 22q11 deletion syndrome (22q11DS) causes a developmental disorder during the embryonic stage, usually because of hemizygous deletions. The clinical pictures of patients with 22q11DS vary because of polymorphisms: on average, approximately 93% of affected individuals have a de novo deletion of 22q11, and the rest have inherited the same deletion from a parent. Methods using multiple genetic markers are thus important for the accurate detection of these microdeletions.

Methods

We studied 12 babies suspected to carry 22q11DS and 18 age-matched healthy controls from unrelated Taiwanese families. We determined genomic variance using microarray-based comparative genomic hybridization (array-CGH), quantitative real-time polymerase chain reaction (qPCR) and multiplex ligation-dependent probe amplification (MLPA).

Results

Changes in genomic copy number were significantly associated with clinical manifestations for the classical criteria of 22q11DS using MPLA and qPCR (p < 0.01). An identical deletion was shown in three affected infants by MLPA. These reduced DNA dosages were also obtained partially using array-CGH and confirmed by qPCR but with some differences in deletion size.

Conclusion

Both MLPA and qPCR could produce a clearly defined range of deleted genomic DNA, whereas there must be a deleted genome that is not distinguishable using MLPA. These data demonstrate that such multiple genetic approaches are necessary for the unambiguous molecular detection of these types of complicated genomic syndromes.
An unexpected phosphate binding site in Glyceraldehyde 3-Phosphate Dehydrogenase: Crystal structures of apo, holo and ternary complex of Cryptosporidium parvum enzyme
Authors: Cook William J , Senkovich Olga , Chattopadhyay Debasish
Published: February 2009

Background

The structure, function and reaction mechanism of glyceraldehyde 3-phosphate dehydrogenase (GAPDH) have been extensively studied. Based on these studies, three anion binding sites have been identified, one 'Ps' site (for binding the C-3 phosphate of the substrate) and two sites, 'Pi' and 'new Pi', for inorganic phosphate. According to the original flip-flop model, the substrate phosphate group switches from the 'Pi' to the 'Ps' site during the multistep reaction. In light of the discovery of the 'new Pi' site, a modified flip-flop mechanism, in which the C-3 phosphate of the substrate binds to the 'new Pi' site and flips to the 'Ps' site before the hydride transfer, was proposed. An alternative model based on a number of structures of B. stearothermophilus GAPDH ternary complexes (non-covalent and thioacyl intermediate) proposes that in the ternary Michaelis complex the C-3 phosphate binds to the 'Ps' site and flips from the 'Ps' to the 'new Pi' site during or after the redox step.

Results

We determined the crystal structure of Cryptosporidium parvum GAPDH in the apo and holo (enzyme + NAD) state and the structure of the ternary enzyme-cofactor-substrate complex using an active site mutant enzyme. The C. parvum GAPDH complex was prepared by pre-incubating the enzyme with substrate and cofactor, thereby allowing free movement of the protein structure and substrate molecules during their initial encounter. Sulfate and phosphate ions were excluded from purification and crystallization steps. The quality of the electron density map at 2Å resolution allowed unambiguous positioning of the substrate. In three subunits of the homotetramer the C-3 phosphate group of the non-covalently bound substrate is in the 'new Pi' site. A concomitant movement of the phosphate binding loop is observed in these three subunits. In the fourth subunit the C-3 phosphate occupies an unexpected site not seen before and the phosphate binding loop remains in the substrate-free conformation. Orientation of the substrate with respect to the active site histidine and serine (in the mutant enzyme) also varies in different subunits.

Conclusion

The structures of the C. parvum GAPDH ternary complex and other GAPDH complexes demonstrate the plasticity of the substrate binding site. We propose that the active site of GAPDH can accommodate the substrate in multiple conformations at multiple locations during the initial encounter. However, the C-3 phosphate group clearly prefers the 'new Pi' site for initial binding in the active site.
Hydroxyethylstarch impairs renal function and induces interstitial proliferation, macrophage infiltration and tubular damage in an isolated renal perfusion model
Authors: Hüter Lars , Simon Tim-Philipp , Weinmann Lenard , Schuerholz Tobias , Reinhart Konrad , Wolf Gunter , Amann Kerstin Ute , Marx Gernot
Published: February 2009

Introduction

The aim of the study was to evaluate some of the underlying pathomechanisms of hydroxyethylstarch (HES) induced adverse effects on renal function using 24 porcine kidneys in an isolated perfusion model over six hours.

Methods

Infusion of either 10% HES 200/0.5, 6% HES 130/0.42 or Ringer's lactate (RL) was performed to achieve an haematocrit of 20% in eight kidneys from four animals per group. Physiological and pathophysiological parameters were determined (including N-acetyl-beta-aminoglucosidase as a marker for lysosomal tubular damage). Histological investigations and immunohistological stainings of the kidneys were performed.

Results

Initially after haemodilution, HES 130/0.42 and HES 200/0.5 reduced urine output compared with RL (P < 0.01). After six hours, N-acetyl-beta-aminoglucosidase was significantly higher in HES 200/0.5 (81 ± 23 U/L) compared with HES 130/0.42 (38 ± 12 U/L) and RL (21 ± 13 U/L; P < 0.001). Osmotic nephrosis-like lesions (OL) of the tubuli were present in all groups showing a significantly lower number of OL in RL (1.1 ± 0.4; P = 0.002) compared with both HES groups (HES 200/0.5 = 2.1 ± 0.6; HES 130/0.42 = 2.0 ± 0.5). Macrophage infiltration was significantly higher in HES 200/0.5 compared with HES 130/0.42 (1.3 ± 1.0 vs. 0.2 ± 0.04; P = 0.044). There was a significant increase in interstitial cell proliferation in the HES 200/0.5 group vs. HES 130/0.42 (18.0 ± 6.9 vs. 6.5 ± 1.6; P = 0.006) with no significant difference in RL (13.5 ± 4.0).

Conclusions

We observed impaired diuresis and sodium excretion by HES and identified renal interstitial proliferation, macrophage infiltration and tubular damage as potential pathological mechanisms of HES-induced adverse effects on renal function using an isolated porcine renal perfusion model. Furthermore, we demonstrated that 10% HES 200/0.5 had more of a pro-inflammatory effect compared with 6% HES 130/0.42 and caused more pronounced tubular damage than 6% HES 130/0.42 and RL. OL were present in all groups, but to a lesser degree after RL administration.
Clinical relevance of the severe abnormalities of the T cell compartment in septic shock patients
Authors: Monserrat Jorge , de Pablo Raul , Reyes Eduardo , Díaz David , Barcenilla Hugo , Zapata Manuel R , De la Hera Antonio , Prieto Alfredo , Álvarez-Mon Melchor
Published: February 2009

Introduction

Given the pivotal role of T lymphocytes in the immune system, patients with septic shock may show T cell abnormalities. We have characterised the T cell compartment in septic shock and assess its clinical implications.

Methods

T lymphocytes from the peripheral blood of 52 patients with septic shock and 36 healthy control subjects were analysed on admission to the intensive care unit, baseline, and 3, 7, 14 and 28 days later. T cell phenotypes (CD3+CD4+/CD3+CD8+, CD45RA+/CD45RO+, CD62L+/CD28+) were assessed by quantitative flow cytometry.

Results

CD3+, CD3+CD4+ and CD3+CD8+ lymphocyte counts were significantly lower in patients with septic shock than control subjects. In surviving patients, CD3+CD4+ lymphocytes had normalised after 14 days, yet CD3+CD8+ numbers were still low. Non effector CD45RA+CD45RO- subsets of CD3+CD4+ and CD3+CD8+ were persistently low during patient follow up. CD3+CD8+CD28+ and CD3+CD8+CD62L+ were reduced in patients versus controls and survivors versus nonsurvivors in the first three days. A prediction receptor operative curve revealed that for the CD3+CD8+CD28+ subset, a cutoff of 136 cells/ml showed 70% sensitivity and 100% specificity for predicting death and the area under the curve was 0.84 at admission. Corresponding values for CD3+CD8+CD62L+ were 141 cells/ml, 60% sensitivity, 100% specificity and an area under the curve of 0.75.

Conclusions

A severe redistribution of T lymphocyte subsets is found in septic shock patients. A different kinetic pattern of T cell subset involvement is observed in surviving and nonsurviving patients, with lower numbers of circulating CD3+CD8+CD28+ and CD3+CD8+CD62L+ associated with a better disease outcome.
Infancy Weight Gain Predicts Childhood Body Fat and Age at Menarche in Girls
Authors: Ong Ken K. , Emmett Pauline , Northstone Kate , Golding Jean , Rogers Imogen , Ness Andrew R. , Wells Jonathan C. , Dunger David B.
Published: February 2009

Context: Rapid postnatal weight gain has been associated with subsequent increased childhood adiposity. However, the contribution of rapid weight gain during specific infancy periods is not clear.

Objective: We aimed to determine which periods of infancy weight gain are related to childhood adiposity and also to age at menarche in UK girls.

Design, Setting, and Participants: A total of 2715 girls from a prospective UK birth cohort study participated in the study.

Main Outcome Measures: Routinely measured weights and lengths at ages 2, 9, and 19 months were extracted from the local child health computer database. Body composition was assessed by dual-energy x-ray absorptiometry at age 10 yr, and age at menarche was assessed by questionnaire (categorized into three groups: <12.0, 12.0–13.0, and >13.0 yr).

Results: Faster early infancy weight gain between 0 and 2 months and also 2 to 9 months were associated with increased body fat mass relative to lean mass at age 10 yr and also with earlier age at menarche. Each +1 unit gain in weight sd score between 0 and 9 months was associated with an odds ratio (95% confidence interval) = 1.48 (1.27–1.60) for overweight (body mass index > 85th centile) at 10 yr, and 1.34 (1.21–1.49) for menarche at less than 12 yr. In contrast, subsequent weight gain between 9 and 19 months was not associated with later adiposity or age at menarche.

Conclusions: In developed settings, rapid weight gain during the first 9 months of life is a risk factor for both increased childhood adiposity and early menarche in girls.
H-Ras is degraded by Wnt/β-catenin signaling via β-TrCP-mediated polyubiquitylation
Authors: Kim Sung-Eun , Yoon Ju-Yong , Jeong Woo-Jeong , Jeon Soung-Hoo , Park Yoon , Yoon Jong-Bok , Park Y. N. , Kim Hoguen , Choi Kang-Yell
Published: February 2009

Ras is an important proto-protein that is regulated primarily by GDP/GTP exchange. Here, we report a novel regulatory mechanism whereby turnover of both endogenous and overexpressed H-Ras protein is controlled by β-TrCP-mediated ubiquitylation, proteasomal degradation and the Wnt/β-catenin signaling pathway. The interaction of H-Ras with the WD40 domain of β-TrCP targeted H-Ras for polyubiquitylation and degradation. This process was stimulated by Axin or adenomatous polyposis coli (Apc), and was inhibited by Wnt3a. Ras-mediated cellular transformation was also inhibited by the expression of β-TrCP and/or Axin. In vivo regulation of Ras stability by Wnt/β-catenin signaling was determined via measurements of the status of Ras in the intestines of mice stimulated with recombinant Wnt3a by intravenous tail vein injection. The regulation of Ras stability by Wnt/β-catenin signaling provides a mechanical basis for crosstalk between the Wnt/β-catenin and the Ras-ERK pathways involved in transformation.
Identification of a palmitoyl acyltransferase required for protein sorting to the flagellar membrane
Authors: Emmer Brian T. , Souther Christina , Toriello Krista M. , Olson Cheryl L. , Epting Conrad L. , Engman David M.
Published: February 2009

Protein palmitoylation has diverse effects in regulating protein membrane affinity, localization, binding partner interactions, turnover and function. Here, we show that palmitoylation also contributes to the sorting of proteins to the eukaryotic flagellum. African trypanosomes are protozoan pathogens that express a family of unique Ca2+-binding proteins, the calflagins, which undergo N-terminal myristoylation and palmitoylation. The localization of calflagins depends on their acylation status. Myristoylation alone is sufficient for membrane association, but, in the absence of palmitoylation, the calflagins localize to the pellicular (cell body) membrane. Palmitoylation, which is mediated by a specific palmitoyl acyltransferase, is then required for subsequent trafficking of calflagin to the flagellar membrane. Coincident with the redistribution of calflagin from the pellicular to the flagellar membrane is their association with lipid rafts, which are highly enriched in the flagellar membrane. Screening of candidate palmitoyl acyltranferases identified a single enzyme, TbPAT7, that is necessary for calflagin palmitoylation and flagellar membrane targeting. Our results implicate protein palmitoylation in flagellar trafficking, and demonstrate the conservation and specificity of palmitoyl acyltransferase activity by DHHC-CRD proteins across kingdoms.
A Larger Slice or a Larger Pie? An Empirical Investigation of Bargaining Power in the Distribution Channel
Authors: Draganska Michaela , Klapper Daniel , Villas-Boas Sofia B.
Published: February 2009

This research aims to provide insights into the determinants of channel profitability and the relative power in the channel by considering consumer demand and the interactions between manufacturers and retailers in an equilibrium model.

We use the Nash bargaining solution to determine wholesale prices and thus how margins are split in the channel. Equilibrium margins are a function of demand primitives and of retailer and manufacturer bargaining power. Bargaining power is itself a function of exogenous retail and manufacturer characteristics. The parties' bargaining positions are determined endogenously from the estimated substitution patterns on the demand side. The more they have to lose in a negotiation relative to an outside option, the weaker the bargaining position. We use the proposed bargaining model to investigate the role of the three main factors that have been blamed for the power shift from manufacturers to retailers in recent years (firm-size increases, store-brand introductions, and service-level differentiation). In our empirical analysis of the German market for coffee, we find that bargaining power varies among the different manufacturer-retailer pairs. This result suggests that bargaining power is not an inherent characteristic of a firm but rather depends on the negotiation partner. We are able to confirm empirically previous theoretical findings that there can be cases where the slice of the pie that goes to one of the channel members may decrease, but the overall pie increases and compensates for the smaller share of profits.
Commentary—Discussion of the Article “Website Morphing”
Authors: Gelman Andrew
Published: February 2009

The article under discussion illustrates the trade-off between optimization and exploration that is fundamental to statistical experimental design. In this discussion, I suggest that the research under discussion could be made even more effective by checking the fit of the model by comparing observed data to replicated data sets simulated from the fitted model.
A Column Generation Algorithm for a Rich Vehicle-Routing Problem
Authors: Ceselli Alberto , Righini Giovanni , Salani Matteo
Published: February 2009

We present an optimization algorithm developed for a provider of software-planning tools for distribution logistics companies. The algorithm computes a daily plan for a heterogeneous fleet of vehicles that depart from different depots and must visit a set of customers for delivery operations. In this rich vehicle-routing problem (VRP), we consider multiple capacities; time windows associated with depots and customers; incompatibility constraints between goods, depots, vehicles, and customers; maximum route length and duration; upper limits on the number of consecutive driving hours and compulsory drivers' rest periods; the possibility of skipping some customers and using express courier services instead of the given fleet to fulfill some orders; the option of splitting up the orders; and the possibility of open routes that do not terminate at depots. Moreover, the cost of each vehicle route is computed through a system of fees depending on the locations visited by the vehicle, the distance traveled, the vehicle load, and the number of stops along the route.

We developed a column generation algorithm where the pricing problem is a particular resource-constrained elementary shortest-path problem, solved through a bounded bidirectional dynamic programming algorithm. We describe how to encode the cost function and the complicating constraints by an appropriate use of resources, and we present computational results on real instances obtained from the software company.
Role of Huperzine a in the Treatment of Alzheimer's Disease
Authors: Desilets Alicia R , Gickas Jennifer J , Dunican Kaelen C
Published: February 2009

Objective:

To review the role of huperzine A in the treatment of Alzheimer's disease (AD).

Data Sources:

A literature search was conducted through MEDLINE (1950–September week 2, 2008), EMBASE (all years), Google Scholar, International Pharmaceutical Abstracts, and a bibliographic review of relevant articles. Key words included huperzine, huperin, Huperzia serrata, and Alzheimer's disease.

Study Selection And Data Extraction:

All clinical trials published in the English language that evaluated huperzine A in patients with AD were included in this review. Articles published in Chinese were included when English abstracts or electronic translation technology were available.

Data Synthesis:

AD is a progressive neurodegenerative brain disorder for which there is no cure; available therapies only decrease cognitive decline. Huperzine A, an alkaloid derived from Chinese club moss (H. serrata), acts as a selective inhibitor of acetylcholinesterase and may also display neuroprotective properties. Preliminary data suggest that huperzine A may improve cognition; studies ranging from 8 to 12 weeks have found improvements in the Mini-Mental State Examination score of 1-5 points.

Conclusions:

Although use of huperzine A has shown promising results in patients with AD, data supporting its use are limited by weak study design. Largescale, randomized, placebo-controlled trials are necessary to establish the role of huperzine A in the treatment of AD.
The impact of omitting the interaction between crossed factors in cross‐classified random effects modelling
Authors: Shi Yuying , Leite Walter , Algina James
Published: February 2009

Cross‐classified random effects modelling (CCREM) is a special case of multi‐level modelling where the units of one level are nested within two cross‐classified factors. Typically, CCREM analyses omit the random interaction effect of the cross‐classified factors. We investigate the impact of the omission of the interaction effect on parameter estimates and standard errors. Results from a Monte Carlo simulation study indicate that, for fixed effects, both coefficients estimates and accompanied standard error estimates are not biased. For random effects, results are affected at level 2 but not at level 1 by the presence of an interaction variance and/or a correlation between the residual of level two factors. Results from the analysis of the Early Childhood Longitudinal Study and the National Educational Longitudinal Study agree with those obtained from simulated data. We recommend that researchers attempt to include interaction effects of cross‐classified factors in their models.
Playing the race card: Making race salient in defence opening and closing statements
Authors: Bucolo Donald O. , Cohn Ellen S.
Published: February 2009

Purpose. Researchers have reported that making a Black defendant's race salient reduces White jurors' tendency to find Black defendants guilty (Sommers & Ellsworth, 2000). We examined whether making race salient by including racially salient statements in the defence attorney's opening and closing statements (i.e., ‘playing the race card’) reduced White jurors' racial bias against a Black defendant.

Method. We obtained scores on racial attitudes for 151 White college students who participated in an experiment where defendant race (Black, White) and race salience (not salient, salient) were manipulated in a between‐subjects design. Participants read one of four trial stimuli and completed dependent measures.

Results. ‘Playing the race card’ reduced White juror racial bias as White jurors' ratings of guilt for Black defendants were significantly lower when the defence attorney's statements included racially salient statements. White juror ratings of guilt for White defendants and Black defendants were not significantly different when race was not made salient. This effect was separate from jurors' level of prejudice (as measured by racial attitudes) as high prejudice participants were more likely than low prejudice participants to find the Black defendant guilty, independent of the race salience manipulation.

Conclusion. Our study indicated that an explicit attempt by a defence attorney to ‘play the race card’ was a beneficial trial strategy a defence attorney could use to reduce White jurors' bias towards Black defendants. However, the beneficial effect of such a strategy may not reduce White jurors' bias towards Black defendants for all White jurors.
Improved Calibration and Correction Techniques for Pressuremeters
Authors: Murat J-R , Lemoigne Y
Published: February 2009

Equipment calibration is essential to the pressuremeter test procedure in order to obtain meaningful results. This paper assesses the accuracy of the standard calibration procedures for a monocell pressuremeter probe. The probe was inserted into sets of instrumented aluminum tubes of various lengths and diameters. The pressure distribution acting against the cavity wall was determined for different levels of probe inflation. Continuous information about the inflation resistance of the probe was also obtained as well as the correlations between the applied pressure, the volume of fluid injected, and the average probe diameter. A more reliable procedure for membrane reaction calibration is then recommended, as well as a new volumetric correction for end perturbations. The influence of low temperatures on the overall behavior of the equipment is also discussed.
A Scientific Basis for the Use of Index Tests in Identification of Expansive Soils
Authors: Sridharan A , Rao SM
Published: February 2009

The paper examines the scientific basis in the use of index properties, such as liquid limit, plasticity index, and activity, for estimating expansivities of natural kaolinitic and montmorillonitic soils by consideration of the fundamental mechanisms governing the soil swelling and plasticity characteristics. Results showed that the physicochemical mechanisms governing the swelling ability and index properties are similar in case of montmorillonitic soils; hence the use of index tests in estimating expansivities of montmorillonitic soils is mechanistically justified. The index properties of kaolinitic soils are not a function of diffuse double layer repulsion (the seat of swelling forces), and hence their employment in prediction of soil expansivities has no scientific basis. Comparison of classifications based on index properties with those obtained from oedometer results for the kaolinitic and montmorillonitic soils indicated that the index tests are better suited for prediction of expansivities of montmorillonitic soils. The results also illustrated that the free-swell procedure earlier proposed by the authors is a more reliable means of estimating expansivities in comparison to index properties and is applicable to both kaolinitic and montmorillonitic soils.
Minimum Test Specimen for Gradation Analysis
Authors: Howard AK , Horz RC
Published: February 2009

Minimum test specimen masses are recommended for gradation analysis testing. The specimen is based on the accuracy required and the maximum particle size present in the soil being tested. For gradation analyses to be reported to the nearest 1 percentage point, the minimum test specimen mass should be at least 100 times the mass of an idealized maximum size particle.
A New Apparatus for the Evaluation of Electro-Kinetic Processes in Hazardous Waste Management
Authors: Yeung AT , Sadek SM , Mitchell JK
Published: February 2009

Possible uses of electro-kinetics for hazardous waste site remediation are being investigated. This paper describes a new apparatus which has been specifically designed, fabricated, and assembled to evaluate the viability, feasibility, practicality, and potential costs of these conceivable techniques experimentally. Results of studies on the existence of electro-osmotic flow in compacted clay and the electro-kinetic barrier to contaminant transport are used to illustrate the types of information that can be obtained by the apparatus.
Long-Term Filtration Behaviour of Soil-Geotextile System
Authors: Rao GV , Gupta KK , Pradhan MPS
Published: February 2009

In addition to soil retention and permeability requirements for a geotextile filter, a geotextile should be able to function without having a significant number of its openings clogged. In order to evaluate the long-term filtration behaviour of a soil-geotextile system, a permeameter is developed in which both the long-term flow rates as well as the gradient ratio tests can be conducted simultaneously for different soils at different densities. Uniformly graded Ottawa sand mixed with various percentages of fine-grained silty soil is used to represent the unstable soil condition for internal soil migration. Two types of needle-punched nonwoven and one type of woven geotextiles are used whose opening sizes satisfy the soil retention criteria for the soil mixtures used.

An unstable flow behaviour is observed during the initial period of filtration. Fine soil particles move toward the geotextile and are either trapped within the geotextile or retained upstream, decreasing the flow rate of the soil-geotextile system. Continuous reduction in flow rate is observed which finally reaches a constant stabilized value. It is also observed that the fine soils adjacent to the geotextile pass through it and the flow rate increases. The duration of such unstable behaviour and time taken to attain a stabilized flow condition increase with fine contents.

The gradient ratio also attains a stable value in the long run after the formation of a soil filter cake in the soil-geotextile system. The initial unstable period does not indicate true clogging behaviour of the system. In view of this, it is recommended that a long-term stabilized gradient ratio be determined instead of the 24-h gradient ratio.
The Application of Time Domain Reflectometry in Geotechnical Instrumentation
Authors: Look BG , Reeves IN
Published: February 2009

The performance of road pavements and earth structures is dependent on the moisture regime experienced during their service life. One of the practical challenges in understanding moisture regimes in earth structures has been to continuously monitor moisture fluctuations in a nondestructive and reasonably accurate way. The time domain reflectometry (TDR) device shows considerable promise in overcoming many of the drawbacks of traditional techniques. The TDR measures the volumetric moisture content of the soil via a buried sensor (probe). Probes can be buried and monitored remotely, and an immediate result can be obtained.

This paper outlines the principles of the TDR device and its mode of operation. Brief details are presented on the experience gained using the TDR on embankment installations, which are currently being monitored. Scope exists for its wider application in the general field of geotechnical instrumentation.
B-Value Measurements for Granular Materials at High Confining Pressures
Authors: Yamamuro JA , Lade PV
Published: February 2009

The pore-pressure coefficient, B, is used often to check the degree of saturation of triaxial specimens. A B-value approaching unity is taken to indicate full saturation. The B-value has been measured experimentally at high confining pressures (0.07 to 69 MPa) and found to be substantially less than unity, despite full saturation. Although lowered B-values can be evaluated reliably under high-stress conditions, saturation checks are performed most conveniently at low confining pressures.
Dynamic Centrifuge Testing of Soil-Nailed Excavations
Authors: Vucetic M , Tufenkjian MR , Doroudian M
Published: February 2009

A series of dynamic centrifuge tests was conducted on models of soil-nailed excavations. The models were subjected to various levels of horizontal shaking to investigate the seismic stability of their prototypes. The scaling factor was 50 in all tests, the depth of the prototype excavation was H = 7.6 m, and the length of nails in each test varied between 0.33 H and 1 H. The tests revealed the most probable failure mechanism under strong shaking and at the same time showed that soil nailing is an excellent method for earth support in seismic regions. The paper describes details of the testing procedure. The procedure includes selection and preparation of the soil, selection and design of the nails and facing, step-by-step filling of the model box, rough simulation of possible geologic history of the soil, excavation and installation of the nails and facing, cyclic shaking, measurements of accelerations and displacements, excavation and incisions of the nailed soil after the tests, and data processing. The investigation showed that centrifuge testing can successfully simulate dynamic soil-structure interaction for complex geotechnical systems such as soil nailing. However, to incorporate pertinent details of the prototype into the model and to provide the proper boundary conditions, a carefully planned step-by-step testing procedure must be implemented. Limitations of the testing and problems encountered are also discussed.
Some Factors Affecting In Situ Measurement Using the Cambridge Self-Boring Pressuremeter
Authors: Findlay RC , Benoit J
Published: February 2009

Research presented in this paper was conducted to assess the influence of environmental and physical factors on measurements made with the self-boring pressuremeter (SBPM). It was found that temperature changes during deployment and long-term instrument calibration drift can result in misinterpretation of in situ soil properties. It was also observed that neglecting to consider the sequential order of strain arm lift-off and radial confinement in both membrane calibration and data reduction can have an effect on interpretation of horizontal stresses, particularly in soft clays. Control experiments were conducted to quantify the effect of these factors. Based on the results of these experiments, a method for assessing excess pore pressure at the beginning of a test using the standard Cambridge SBPM transducers was developed. This method incorporates findings from temperature behavior tests. In addition, a modified method of membrane stiffness correction is proposed which includes consideration of sequential order of lift-off and confinement effects.
In-Plane Air Flow Through Needle-Punched, Nonwoven Geotextiles Under Normal Loading
Authors: Weggel JR , Gontar WA
Published: February 2009

Knowledge of the in-plane permeability of nonwoven geotextiles to air and other gases has important applications including, for example, the transport and collection of methane gas beneath landfill caps. The results of in-plane flow measurements of air through eight different needle-punched, nonwoven geotextiles are presented. Air flow was measured using a radial flow device under a range of inflow pressures and compressive loads tending to reduce the geotextile's thickness. Inflow pressures ranged from 6.9 to 20.7 kPa (1 to 3 psi), while compressive loads ranged from 13.8 to 372 kPa (2 to 54 psi). The flow through the radial flow device is described mathematically to account for the compressive load borne by the air pressure between the plates of the device. A dimensional analysis of the important variables results in a description of the flow using five dimensionless terms including a dimensionless permeability. The analysis indicates that all eight needle-punched, nonwoven geotextiles, in spite of their variable thickness, differing materials, and differing post-treatment, are essentially identical in their performance in terms of how air flows through them. The intrinsic permeability of all eight geotextiles can be estimated to within 8% (worst case) by the equation k=[1.7578ν4∕3g2∕3[ΔpγΔL]−0.398t−0.659]1.4914 in which k is the in-plane intrinsic permeability, γ is the unit weight of the fluid, Δp is the pressure drop along the flow path, ΔL is the length of the flow path (Δp/ΔL is the pressure gradient), t is the thickness of the geotextile, and v is the kinematic viscosity of the fluid.
A Study of Undrained Shear Strength Using Various Vanes
Authors: Silvestri V , Aubertin M , Chapuis RP
Published: February 2009

A field study of the undrained shear strength of a sensitive clay deposit was carried out by means of various vane configurations. Rectangular, rhomboidal, triangular, and elliptic vane blades were used. The assumption of isotropy of the undrained shear strength indicates that a uniform shear stress distribution gives a better fit to the observed response than a triangular distribution
Mikasa's Direct Shear Apparatus, Test Procedures and Results
Authors: Takada N
Published: February 2009

Mikasa's direct shear apparatus and test procedures are presented. This test apparatus was developed in 1960 to conduct constant volume shear tests, which correspond to undrained shear tests for saturated soils. This apparatus overcomes several defects of the traditional apparatus. The advantages of the direct shear test over the triaxial test are discussed, and typical examples of test results are presented. Some modifications of the test apparatus and procedures permitted automation of constant volume shear tests and unconsolidated undrained shear tests.
Swell Potential Versus Overburden Pressure
Authors: Sikh TS
Published: February 2009

Data were collected and reviewed pertaining to one-dimensional vertical free-swell tests performed on existing fill soils from various projects located in Southern California. The purpose of reviewing the data was to evaluate the effect of overburden pressure on the swelling potential of expansive soils. The swell tests were performed on relatively undisturbed specimens at the in-place moisture content and density under the actual overburden pressure. The data indicate that at an overburden pressure of approximately 1400 lb/ft2 (67 kPa) or greater, the swell potential generally decreases to less than 1%.
Monitoring System for Hydrologic Evaluation of Landfill Covers
Authors: Benson CH , Bosscher PJ , Lane DT , Pliska RJ
Published: February 2009

Three test sections were constructed and instrumented to assess the hydrologic behavior of earthen final covers at two municipal solid waste landfills. A traditional design using a “resistive barrier” was used for two of the test sections, whereas an alternative design using a “capillary barrier” was used for the third test section. The test sections were built in two distinctly different climates: humid with high precipitation (Atlanta, Georgia) and arid (East Wenatchee, Washington). Each test section was instrumented to measure climatologic variables, overland flow, percolation, soil temperature, and soil water content. This paper focuses on the construction and instrumentation of the test sections.

A data acquisition and control computer (DACC) is used to collect data and control various components of the monitoring system. The system in Atlanta is powered by 115 volts alternating current (VAC), whereas the system in Wenatchee is powered by solar panels and batteries. Telecommunications are established via traditional telephone lines or by cellular transmission. Commercially available equipment sold by a variety of vendors was used. After approximately two years of operation, maintenance requirements for the systems have been minimal.

The writers have found that a DACC used to remotely monitor the hydrology of final covers must permit system control and remote access. Selection of robust instruments that require minimal calibration and maintenance is also essential. Experience has shown that selecting the sampling frequency is best accomplished through initially sampling rapidly and then adjusting the sampling frequency to obtain representative data. Periodic manual measurements have also been useful in error checking and in ensuring confidence in the data.
A Multiple Purpose Soil Testing Apparatus
Authors: Huang AB , Hsu SP , Kuhn HR
Published: February 2009

A relatively compact soil testing system that is capable of performing monotonic/cyclic triaxial and torsional simple shear tests has been developed. A high-torque direct-drive, servo/stepper motor is used to provide the driving force. Under the servo mode, the motor could be controlled to provide a constant torque, which is used in stress-controlled tests. Strain-controlled tests are conducted using the stepper control mode. To perform triaxial tests, the rotational motion of the motor is transformed into linear motion using a preloaded ball screw shaft. A preloaded ball spline shaft directly attached to the motor is used to perform torsional simple shear tests. Because there are no gears in the driving system, there is no backlash during reversals of loading directions. The motor is equipped with an encoder and an indexer. The extremely rigid driving system and high resolution of the encoder enable the linear and rotational displacement to be monitored through the encoder/indexer system. Test control and data logging are fully automated using a personal computer. This paper provides details of the apparatus. A set of strain-controlled test data are presented to demonstrate capabilities of the new apparatus.