bluuebunny/crossref_metadata_2025 huggingface dataset:
Experimental study on multiaxial ratcheting behavior of vulcanized natural rubber
Authors: Wang Yanping , Chen Xu , Yu Weiwei , Yan Lei
Published: January 2009

Multiaxial ratcheting characteristics of vulcanized natural rubber (NR) at room temperature were studied experimentally. The effects of axial stress, shear strain amplitude, shear strain rate, and their histories on ratcheting behavior were discussed. It is shown that the ratcheting strain depends on the axial stress and cyclic strain range. The ratcheting strain increases more rapidly as the constant axial stress or shear strain amplitude become larger. The ratcheting behaviors of the rubber exhibit nonsensitivity to the applied cyclic stress rate except initial axial strain. Furthermore, the loading histories also play an important role in progress of ratcheting. The prior cycles with higher axial stress, larger strain range or lower strain rate greatly restrains ratcheting strain of subsequent cycling with lower ones. Influence of creep on ratcheting behavior can not be neglected and its value reaches 87% of ratcheting strain. POLYM. ENG. SCI., 2009. © 2009 Society of Plastics Engineers
Axial‐feed thermoforming of oriented polypropylene tubes
Authors: Elnagmi Mohamed , Bruhis Moisei , Jain Mukesh
Published: January 2009

The effect of newly developed axial feed thermoforming process (AFTF) on mechanical properties and morphology were investigated to gain a better understanding of structure–properties–process relationship. The starting material for AFTF is an oriented polypropylene tube (OPP) produced in uniaxial direction by using solid state extrusion process. Morphological changes from solid‐state extrusion are briefly reported. A die‐less bulge testing system was designed to bulge OPP tube at a high temperature in biaxial direction. Wide‐angle X‐ray diffraction, field emission scanning electron microscope, and optical microscopy were used to characterize the microstructure of the extruded and bulged samples of OPP. In addition, tensile tests were carried out at room temperature of samples machined from the extruded and bulged tubes along the axial and hoop directions. The results show that tensile strength increases with draw ratio in extruded samples as well as improvements in ductility were obtained in die‐less bulge tests with an increase in axial feed. POLYM. ENG. SCI., 2009. © 2009 Society of Plastics Engineers
Finite element modeling of polymer hot embossing using a glass‐rubber finite strain constitutive model
Authors: Dupaix Rebecca B. , Cash William
Published: January 2009

A hyperelastic–viscoplastic constitutive model for amorphous polymers was used in finite element simulations of micro‐hot embossing across the glass transition. The model was selected for its ability to capture finite strain temperature and rate dependence over a wide range of temperatures, including across the glass transition. The simulations focused on the glass transition temperature regime, and particularly probed the effects of time and temperature during cooling and mold release. The results show that strong temperature sensitivity of the material across the glass transition leads to a wide range of required embossing force and springback. The interplay between changes in material properties upon cooling and stress relaxation can lead to significant increases in embossing force during the cooling stage, especially when high cooling rates are employed. The effects of thermal expansion also complicate the problem during rapid cooling. Nonlinear material behavior is shown to affect results in parametric hot embossing studies. Careful tailoring of embossing temperature, cooling rate, and demolding temperature is critical in acceptable feature replication. The best results are found for moderate cooling rates, which allow adequate time for stress relaxation in the material prior to mold release. POLYM. ENG. SCI., 2009. © 2009 Society of Plastics Engineers
Group counseling in the schools
Authors: Pérusse Rachelle , Goodnough Gary E. , Lee Vivian V.
Published: January 2009

Group counseling is an effective intervention when working in a school setting. In this article, the authors discuss the different kinds of groups offered in schools, types of group interventions, strategies to use in forming groups, and how to collaborate with others in the school. Because leading groups in schools is a specialized skill, the authors suggest that group leaders form collaborative relationships with others in the school, allot sufficient time for group counseling, advocate to change policies that might preclude groups in schools, and work with students and teachers to honor the time allotment dedicated to group counseling. © 2009 Wiley Periodicals, Inc.
Promoting cultural competence in counseling Asian American children and adolescents
Authors: Zhou Zheng , Siu Candice R. , Xin Tao
Published: January 2009

Asian Americans are commonly perceived as the diligent and high‐achieving “model minority.” This positive stereotype has negative consequences for this ethnic minority group because it trivializes their social and mental health problems. This image of success has made many overlook the true nature of the struggles many Asian American families have to face in the United States. Scientific literature suggests that Asian American children experience major adjustment problems in school including loneliness, isolation, withdrawal, rejection, anxiety, low self‐esteem, and interpersonal distress. Cultural barriers exist between the Asian and the dominant society and influence Asian Americans' cognitive appraisal and coping choices when personal and emotional problems arise. These barriers also prevent clinicians from identifying and subsequently providing effective mental health services for Asian American children and their families. In this article, the authors examine the Asian cultural conceptions of mental health and various cultural barriers in an attempt to promote cultural understanding and competence among clinicians working with Asian American children and their families. Recommendations for clinical practice and future research directions are provided. © 2009 Wiley Periodicals, Inc.
Impact of a meaning‐centered intervention on job satisfaction and on quality of life among palliative care nurses
Authors: Fillion Lise , Duval Stéphane , Dumont Serge , Gagnon Pierre , Tremblay Isabelle , Bairati Isabelle , Breitbart William S.
Published: January 2009

Objective: Palliative care (PC) nurses experience several recurrent organizational, professional, and individual challenges. To address existential and emotional demands, the meaning‐centered intervention was recently developed. The intervention applied didactic and process‐oriented strategies, including guided reflections, experiential exercises, and education based on themes of Viktor Frankl's logotherapy. The objective of this study was to test its efficiency to improve job satisfaction and quality of life in PC nurses from three regional districts in Quebec Province, Canada.

Methods: A randomized waiting‐list group design was conducted, intervention group (n=56) versus waiting‐list group (n=53). Job satisfaction, perception of benefits of working in PC, and spiritual and emotional quality of life were measured at pre‐, posttest, and 3‐month follow‐up.

Results: The PC nurses in the experimental group reported more perceived benefits of working in PC after the intervention and at follow‐up. Spiritual and emotional quality of life remained, however, unaffected by the intervention.

Conclusions: To explain null findings, theoretical and methodological challenges, related to existential interventions, such as choice of outcomes, and selection bias (participants recruited were healthy workers) are discussed. Future directions and strategies to deal with those issues are proposed. Copyright © 2009 John Wiley & Sons, Ltd.
Pesticide use in ornamental production: what are the benefits?
Authors: Bethke James A , Cloyd Raymond A
Published: January 2009

Pest control in ornamental production is challenging owing to the diversity of crops grown, the desired aesthetic perfection, the potential economic loss due to failure and the multitude of arthropod pests encountered. Agricultural crops of less value per acre, such as row crops, can tolerate a certain level of damage from arthropod pests without compromising yields. Damage thresholds for ornamentals, however, are essentially zero. Pesticides are a viable method of protection for such a crop in lieu of alternatives. Therefore, the purpose of this paper is to emphasize the importance of pesticides to the ornamental industry. Pesticides provide many benefits to ornamental producers, including: (1) consistent availability; (2) rapid kill; (3) reliable and consistent control; (4) increased crop production and quality; (5) they may be used to prevent movement of invasive pests; (6) they are less expensive (in general) than alternatives; (7) they may reduce plant pathogenic transmission; (8) they may be used in conjunction with natural enemies. Pesticide use will continue to be a significant strategy for dealing with arthropod pests so that ornamental producers can stay competitive in both national and international markets. Copyright © 2009 Society of Chemical Industry
Resistance of Pakistani field populations of spotted bollworm Earias vittella (Lepidoptera: Noctuidae) to pyrethroid, organophosphorus and new chemical insecticides
Authors: Ahmad Mushtaq , Iqbal Arif M
Published: January 2009

BACKGROUND: The spotted bollworm Earias vittella (Fab.) is a serious pest of cotton and okra in Pakistan. Owing to persistent use of insecticides, this pest has developed resistance, especially to pyrethroids. The present studies aimed at determining the extent of resistance to pyrethroid, organophosphorus and new chemical insecticides in Pakistani populations of E. vittella.

RESULTS: Field populations of E. vittella were monitored at Multan, Pakistan, from 1999 to 2007 for their resistance against six pyrethroid, four organophosphorus and six new chemical insecticides using a leaf‐dip bioassay. Of the pyrethroids, resistance was generally low to zeta‐cypermethrin and moderate to high or very high to cypermethrin, deltamethrin, esfenvalerate, bifenthrin and lambda‐cyhalothrin. Resistance to organophosphates chlorpyrifos, profenofos, triazophos and phoxim was recorded at very low to low levels. Among new chemicals, E. vittella had no or a very low resistance to spinosad, emamectin benzoate and methoxyfenozide, a very low to low resistance to abamectin, a very low to moderate resistance to indoxacarb and a moderate resistance to chlorfenapyr.

CONCLUSION: The results indicate a lack of cross‐resistance between pyrethroid and organophosphorus insecticides in E. vittella. Rotation of insecticides showing no, very low or low resistance, but belonging to different insecticide classes with unrelated modes of action, may prevent or mitigate insecticide resistance in E. vittella. Copyright © 2009 Society of Chemical Industry
Mutations in the mitochondrial cytochrome b of Tetranychus urticae Koch (Acari: Tetranychidae) confer cross‐resistance between bifenazate and acequinocyl
Authors: Van Nieuwenhuyse Pieter , Van Leeuwen Thomas , Khajehali Jahangir , Vanholme Bartel , Tirry Luc
Published: January 2009

BACKGROUND: Resistance of Tetranychus urticae Koch to bifenazate was recently linked with mutations in the mitochondrial cytochrome b Qo pocket, suggesting that bifenazate acts as a Qo inhibitor (QoI). Since these mutations might cause cross‐resistance to the known acaricidal QoI acequinocyl and fluacrypyrim, resistance levels and inheritance patterns were investigated in several bifenazate‐susceptible and bifenazate‐resistant strains with different mutations in the cd1 and ef helices aligning the Qo pocket.

RESULTS: Cross‐resistance to acequinocyl in two bifenazate‐resistant strains was shown to be maternally inherited and caused by the combination of two specific mutations in the cytochrome b Qo pocket. Although most investigated strains were resistant to fluacrypyrim, resistance was not inherited maternally, but as a monogenic autosomal highly dominant trait. As a consequence, there was no correlation between cytochrome b genotype and fluacrypyrim resistance.

CONCLUSIONS: Although there is no absolute cross‐resistance between bifenazate, acequinocyl and fluacrypyrim, some bifenazate resistance mutations confer cross‐resistance to acequinocyl. In the light of resistance development and management, high prudence is called for when alternating bifenazate and acequinocyl in the same crop. Maternally inherited cross‐resistance between bifenazate and acequinocyl reinforces the likelihood of bifenazate acting as a mitochondrial complex III inhibitor at the Qo site. Copyright © 2009 Society of Chemical Industry
Effect of different formulations on tebuconazole residues in stone fruits
Authors: Lucini Luigi , Molinari Gian Pietro
Published: January 2009

BACKGROUND: The correlation between pesticide residue levels and formulation of an active substance is often not considered, even if it is reasonable to expect some differences arising from behaviour during dilution and spraying, from adhesion to plant and from degradation. An experimental study to investigate the magnitude of tebuconazole residues as a function of different tebuconazole formulated products was carried out in Italy. The fungicide was applied as wettable powder (WP) and water‐dispersible granule (WG) formulations to peach, plum, apricot and nectarine orchards, on four different sites. The fruit samples gained from the field trials were quantitatively analysed by gas chromatography with a nitrogen phosphorus detector (GC/NPD) for tebuconazole residues.

RESULTS: Tebuconazole residues in the fruits gained from the plot treated with the WP formulation, 14 days after application, were in the range 0.01–0.07 mg kg−1, while corresponding residues in the plot treated with the WG formulation were in the range 0.01–0.06 mg kg−1.

CONCLUSION: No significant differences in the residue levels of tebuconazole could be observed between the trials conducted with the WP and the WG formulation. Copyright © 2009 Society of Chemical Industry
Optical instabilities in semiconductor quantum‐well systems driven by phase‐space filling
Authors: Schumacher Stefan , Kwong N. H. , Binder R. , Smirl Arthur L.
Published: January 2009

Four‐wave mixing (FWM) is one of the best known phenomena in semiconductor optics. Recent experimental results of FWM instabilities and optical switching in atomic systems have renewed the interest in FWM and possible related instabilities in semiconductors. We have recently performed theoretical investigations of FWM instabilities in a variety of semiconductor quantum well systems (single quantum wells, Bragg‐spaced multiple quantum wells, and planar semiconductor micocavities) and shown that different systems require different physical processes that potentially can give rise to FWM instabilities. In this contribution, we concentrate on the simple (and largely academic) finding that phase‐space filling together with spatial exciton dispersion can lead to FWM instabilities in single quantum wells. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Resveratrol attenuates 1,2‐dimethylhydrazine (DMH) induced glycoconjugate abnormalities during various stages of colon carcinogenesis
Authors: Sengottuvelan Murugan , Deeptha Kumaraswamy , Nalini Namasivayam
Published: January 2009

Although a myriad of health promoting effects has been attributed to resveratrol (Res) (3,5,4′‐trihydroxy‐trans‐stilbene), a phytoalexin, the most interesting is its anticancer property. The aim of this work was to elucidate the effectiveness of Res against cellular transformation (glycoconjugate alterations) initiated by 1,2‐dimethylhydrazine (DMH), a colon specific carcinogen. Group 1 were control rats, group 2 were control rats that received Res (8 mg/kg body weight orally every day), rats in groups 3–6 were treated weekly with DMH (20 mg/kg body weight, subcutaneously × 15 times). In addition, groups 4–6 received Res (as in group 2) in three dietary regimens: initiation (I), post‐initiation (PI) and entire period (EP). At the end of the 30 week experimental period in DMH alone exposed rats, altered levels of glycoconjugates (total hexoses, fucose, hexosamine and sialic acid) were observed in liver, intestine and colon tissues. Of the three dietary regimens of Res, the entire period supplementation significantly (p < 0.01) modulated the levels of glycoconjugates and reduced the incidence of adenoma and adenocarcinoma. These findings suggest that Res may extend its chemopreventive effect by restoring the alteration in glycoconjugates that are thought to be involved in the colonic malignant transformation process in this experimental model. Copyright © 2009 John Wiley & Sons, Ltd.
Electron ionization mass spectrometric study of substituted alloxazine‐5‐oxides and iso‐alloxazine‐5‐oxide
Authors: Prukała Dorota , Sikorski Marek
Published: January 2009

The fragmentation pathways in electron ionization (EI) mass spectra of a series of new N(5)‐oxides of alloxazines and iso‐alloxazine are presented, and compared with those of substituted alloxazines and iso‐alloxazine. The EI mass spectra of these compounds showed characteristic fragmentation pathways A, B and C, started by the ejection of atomic oxygen, a HNCO molecule and an OH. radical, respectively. On the basis of B/E and B2/E spectra, the mechanism of elimination of the OH. radical is discussed. The influence of the methyl substituent in the benzene ring of alloxazine on the mass fragmentation pathways is described. Copyright © 2009 John Wiley & Sons, Ltd.
Comparison of atmospheric pressure photoionization and electrospray ionization mass spectrometry for the analysis of UV filters
Authors: Rodil Rosario , Schrader Steffi , Moeder Monika
Published: January 2009

A comparison was made between the electrospray ionization (ESI) and atmospheric pressure photoionization (APPI) tandem mass spectrometric (MS/MS) responses of eleven ultraviolet (UV) filters. Four of the target compounds were favourably ionized in negative ion mode, and the other seven compounds in positive ion mode. For nine of the compounds APPI generated a similar response to that of ESI, but the APPI signal‐to‐noise (S/N) ratios were 1.3–60 times higher. The two most polar of the UV filter compounds (PBSA and BP‐4) were more efficiently ionized by ESI, offering higher signal intensities and lower detection limits. APPI was, however, less susceptible to ion suppression than ESI when real samples were injected. In order to optimize the APPI conditions different dopant solvents were examined to enhance the efficiency of the photoionization process. Among the evaluated dopants, toluene was selected as the best compromise. At a toluene flow rate of 10% of the solvent flow rates the ionization response increased by a factor of 40–50 over the use of no dopant for the compounds in positive ion mode and by more than 300 for the compounds in negative ion mode. Copyright © 2009 John Wiley & Sons, Ltd.
Imaging mass spectrometry for examining localization of polymeric composition in matrix‐assisted laser desorption/ionization samples
Authors: Weidner Steffen M. , Falkenhagen Jana
Published: January 2009

The localization of polymeric composition in samples prepared for matrix‐assisted laser desorption/ionization (MALDI) analysis has been investigated by imaging mass spectrometry. Various matrices and solvents were used for sample spot preparation of a polybutyleneglycol (PBG 1000). It was shown that in visibly homogeneous spots, prepared using the ‘dried droplet’ method, separation between matrix and polymer takes place. Moreover, using α‐cyano‐4‐hydroxycinnamic acid (CCA) as matrix and methanol as solvent molecular mass separation of the polymer homologues in the spots was detectable. In contrast to manually spotted samples, dry spray deposition results in homogeneous layers showing no separation effects. Copyright © 2009 John Wiley & Sons, Ltd.
Interaction of Guar and Xanthan Gums with Starch in the Gels Obtained from Normal, Waxy and High‐amylose Corn Starches
Authors: Weber Fernanda H. , Clerici Maria Teresa P. S. , Collares‐Queiroz Fernanda P. , Chang Yoon K.
Published: January 2009

The objectives of the present study were to analyze the chemical interactions between guar and xanthan gums and starches. Gels were obtained from normal (NCS), waxy (WCS) and high‐amylose (HACS) corn starches containing gums. The gels were evaluated according to their pasting properties and infra‐red absorption. The guar (GG) and xanthan (XG) gums affected the properties of the NCS paste more significantly than those of the WCS paste. In the infra‐red absorption spectra, no covalent bonds between the starches and gums were observed under the conditions studied, so probably the only interactions occurring between them were hydrogen bonds.
The Influence of Modified Starch on the Process Water Quality in Papermaking and the Paper Properties
Authors: Zakrajšek Nejc , Golob Janvit
Published: January 2009

The influence of modified (cationic) starch on the process water quality in papermaking and paper properties has been investigated. The experiments were conducted on sulfate hardwood pulp by applying both tap and paper mill process water. When process water is used, the retained amount of starch on fibers decreases, which most probably results from a partial neutralization of the cationic charge on modified starch, thereby reducing its attraction to the anionic groups on a fiber. By adding the modified starch, the turbidity of process water is to some extent reduced, indicating that the suspended organic substances are removed from process water. Due to starch accumulation, the load of process water by organic substances (determined via the TOC analysis) is not reduced, but is rather increased when the modified starch is added. In most cases, the addition of modified starch improved the investigated paper properties. However, these properties varied in correlation with the quality of the used water, despite the fact that the dosage of modified starch remained constant. This demonstrates the influence of process water quality, not only on the paper properties, but also on the efficiency of process chemicals, such as the modified starch, in the papermaking process.
Enabling system evolution through configuration management on the hardware/software boundary
Authors: Krikhaar René , Mosterman Wim , Veerman Niels , Verhoef Chris
Published: January 2009

As the use of software and electronics in modern products is omnipresent and continuously increasing, companies in the embedded systems industry face increasing complexity in controlling and enabling the evolution of their IT‐intensive products. Traditionally, product configurations and their updates were managed separately for the hardware and software discipline. At specified release moments during the development of their products, the hardware and software were released together. But, as the usage, flexibility and complexity of software and electronics increases, and fierce competition requires shorter time‐to‐market and customizable products, more frequent releases of integrated hardware and software configurations becomes necessary. This evolution requires adequate configuration management both within the hard‐ and software disciplines and across them. In many organizations, software configuration management is more visibly established than hardware configuration management due to the inherent flexibility and complexity of software. But as the flexibility of hardware has increased through the use of configurable hardware, the need for more intense hardware configuration management increased as well. To properly enable the evolution of integrated hardware/software systems, adequate configuration management is required in both disciplines. Our article deals with just that: configuration management on the hardware/software boundary, and is mainly focused on the product development phase. The hardware/software boundary has a broad scope; in this article we focus on embedded systems containing software and custom and off‐the‐shelf electronic hardware, thereby concentrating on configurable hardware containing both software and hardware designs. It is important to note that the concepts of our article apply to configuration management issues that go beyond that scope. We investigated the configuration management practices in six large organizations in the embedded systems industry, including medical devices, defense equipment, optics, document processing, and semiconductor equipment. In particular, we looked at programmable/configurable hardware, as the use and complexity of this technology continue to increase. We propose a generic development cycle with real‐life examples to illustrate the configuration management concepts. Then, from the sociotechnical design point of view, we raise awareness and argue that configuration management tools, processes, and its organization must be further aligned to support the complexity and interdisciplinary nature of the hardware/software boundary of evolving embedded systems. © 2009 Wiley Periodicals, Inc. Syst Eng
Microcystin extracts induce ultrastructural damage and biochemical disturbance in male rabbit testis
Authors: Liu Ying , Xie Ping , Qiu Tong , Li Hui‐Ying , Li Guang‐Yu , Hao Le , Xiong Qian
Published: January 2009

In the present research, the changes of ultrastructures and biochemical index in rabbit testis were examined after i.p. injection with 12.5 μg/kg microcystin (MC) extracts. Ultrastructural observation showed widened intercellular junction, distention of mitochondria, endoplasmic reticulum, and Golgi apparatus. All these changes appeared at 1, 3, and 12 h, but recovered finally. In biochemical analyses, the levels of lipid peroxidation (MDA) and H2O2 increased significantly at 1 h, indicating MC‐caused oxidative stress. Finally, H2O2 decreased to the normal levels, while MDA remained at high levels. The antioxidative enzymes (CAT, SOD, GPx, GST) and antioxidants (GSH) also increased rapidly at 1 h, demonstrating a quick response of the defense systems to the oxidative stress. Finally, the activity of CAT, SOD, and GPX recovered to the normal level, while the activity of GST and the concentration of GSH remained at a high level. This suggests that the importance of MCs detoxification by GST via GSH, and the testis of rabbit contained abundant GSH. The final recovery of ultrastructure and some biochemical indexes indicates that the defense systems finally succeeded in protecting the testis against oxidative damage. In conclusion, these results indicate that the MCs are toxic to the male rabbit reproductive system and the mechanism underlying this toxicity might to be the oxidative stress caused by MCs. Although the negative effects of MCs can be overcome by the antioxidant system of testis in this study, the potential reproductive risks of MCs should not be neglected because of their wide occurrence. © 2009 Wiley Periodicals, Inc. Environ Toxicol 2010.
Effect of single‐mineral filler and hybrid‐mineral filler additives on the properties of polypropylene composites
Authors: Nurdina A.K. , Mariatti M. , Samayamutthirian P.
Published: January 2009

The present study was carried out to determine the filler characteristics and to investigate the effects of three types of mineral fillers (CaCO3, silica, and mica) and filler loadings (10–40 wt%) on the properties of polypropylene (PP) composites. The characteristics of the particulate fillers, such as mean particle size, particle size distribution, aspect ratio, shape, and degree of crystallinity were identified. In terms of mechanical properties, for all of the filled PP composites, Young's modulus increased, whereas tensile strength and strain at break decreased as the filler loading increased. However, 10 wt% of mica in a PP composite showed a tensile strength comparable with that of unfilled PP. Greater tensile strength of mica/PP composites compared to that of the other composites was observed because of lower percentages of voids and a higher aspect ratio of the filler. Mica/PP also exhibited a lower coefficient of thermal expansion (CTE) compared to that of the other composites. This difference was due to a lower degree of crystallinity of the filler and the CTE value of the mica filler. Scanning electron microscopy was used to examine the structure of fracture surfaces, and there was a gradual change in tensile fracture behavior from ductile to brittle as the filler loading increased. The nucleating ability of the fillers was studied with differential scanning calorimetry, and a drop in crystallinity of the composites was observed with the addition of mineral filler. Studies on the hybridization effect of different (silica and mica) filler ratios on the properties of PP hybrid composites showed that the addition of mica to silica‐PP composites enhanced their tensile strength and modulus. J. VINYL ADDIT. TECHNOL., 2009. © 2009 Society of Plastics Engineers
Retention of basic laparoscopic skills after a structured training program
Authors: Hiemstra E. , Kolkman W. , van de Put M. A. J. , Jansen F. W.
Published: January 2009

The purpose of this study was to test the retention of basic laparoscopic skills on a box trainer 1 year after a short training program. For a prior study, eight medical students without prior experience (novices) underwent baseline testing, followed by five weekly training sessions and a final test. During each of seven sessions, they performed five tasks on an inanimate box trainer. Scores were calculated by adding up the time to completion of the task with penalty points, consequently rewarding speed and precision. The sum score was the sum of the five scores. One year later, seven of them underwent retention testing for the current study. The final test results were compared with retention test results as a measure of durability of acquired skills. Novices’ scores did not worsen significantly for four out of five tasks (i.e., placing a pipe cleaner p = 0.46, placing beads p = 0.24, cutting a circle p = 0.31, and knot tying p = 0.13). However, deterioration was observed in the performance on stretching a rubber band (p < 0.05), as well as in the sum score (p < 0.05). Nevertheless, all retention scores remained better than the baseline results. In conclusion, basic laparoscopic skills acquired during a short training program merely sustain over time. However, ongoing practice is advisable, especially to preserve tissue-handling skills, since these may be the first to deteriorate.
The screening of SLC6A8 deficiency among Estonian families with X‐linked mental retardation
Authors: Puusepp H. , Kall K. , Salomons G. S. , Talvik I. , Männamaa M. , Rein R. , Jakobs C. , Õunap K.
Published: January 2009

The urinary creatine:creatinine (Cr:Crn) ratio was measured in males from 49 families with a family history compatible with X‐linked mental retardation (XLMR) in order to estimate the prevalence of SLC6A8 deficiency in Estonia. We identified 11 boys from 9 families with an increased urinary Cr:Crn ratio (18%). In three related boys, a hemizygous missense mutation (c.1271G>A; p.Gly424Asp) was identified. Their mother was heterozygous for the same mutation. Although many missense mutations have been described, the p.Gly424Asp mutation has not been previously reported. The clinical expression varied widely among affected males of this family. Patients 1 and 3 had relatively mild clinical expression (mild mental retardation (MR) and attention deficit disorder), but patient 2 had all typical clinical signs of SLC6A8 defect such as moderate MR, autistic features, expressive dysphasia and epilepsy. Among our patients, we saw significant problems in speech and language development combined with attention and behavioural difficulties. The number of false‐positive biochemical results with increased urinary Cr:Crn ratio was higher (18%) in our study than in previous reports (1.8–10%). We therefore suggest that repeated biochemical testing should be performed before DNA sequencing analysis. Our study suggests that 2% (95% confidence limits: 0.05–11.1%) of this Estonian XLMR panel are due to mutations in the SLC6A8, which is similar to the prevalence reported in other populations. We therefore conclude that creatine transporter deficiency is a relatively common genetic disorder in males with sporadic or familiar MR and diagnostic screening of them should always include screening for SLC6A8 deficiency.
Does parenting mediate the effects of exposure to violence on violent behavior? An ecological–transactional model of community violence
Authors: Spano Richard , Vazsonyi Alexander T. , Bolland John
Published: January 2009

Three waves of longitudinal data from a high poverty sample of 1544 African American youth were used to test an ecological–transactional model of violence. SEM analyses were conducted to determine whether parenting (Time 2) mediated the effects of exposure to violence (Time 1) on violent behaviors (Time 3). Findings supported the specified model. Multigroup SEM analyses indicated that neither family structure nor developmental stage (early versus middle/late adolescence) moderated these effects. However, exposure to violence had a larger effect on violent behaviors in female versus male youth, although the difference was simply in magnitude, not direction. A final model that predicted change scores also provided support for the hypothesized ecological–transactional model of violence.
Increased ‐1 ribosomal frameshifting efficiency by yeast prion‐like phenotype [PSI+]
Authors: Park Hee Jung , Park So Jung , Oh Doo-Byoung , Lee Sangho , Kim Yang-Gyun
Published: January 2009

Programmed ‐1 ribosomal frameshifting (‐1RF) is usually regulated by a slippery sequence and an RNA secondary structure but can be affected by the slippery sequence combined with translational perturbation. Dramatic increases of ‐1RF efficiencies arise from the slippery sequences in [PSI+], an epigenetic modifier of translation termination fidelity. Curing of [PSI+] abolished such increases of ‐1RF efficiency. Enhanced ‐1RF frequency at the slippery sequences could be another physiological effect induced directly or indirectly by the perturbation of the translation process in [PSI+] cells.
Jihad in West Africa: early phases and inter-relations in Mauritania and Senegal
Authors: Curtin Philip D.
Published: January 2009

The tradition of religious revolution directed against partially Muslim rulers is traced to the religious reform movement among the zwāya of Mauritania in the 1660s, and to the jihad that brought them briefly into control of Futa Toro, Cayor, Walo, and Jolof in the 1670s. In spite of the reconquest of these states by their secular rulers and the re-establishment of Hassānī control in southwestern Mauritania, the tradition of religious revolt and the aim of establishing an imamate under religious leadership lived on, to reappear in other Fulbe states. It came a generation later, with the jihad of Malik Sy in Bundu during the 1690s, and direct connexions can be traced between the leadership in Bundu and the leadership in the later jihad in Futa Jallon. The jihad in Futa the 1770s and 1780s followed in the same tradition. This evidence suggests that the external influence of the mid-eighteenth-century revival of Islam in Arabia and the Middle East has been overemphasized in West African religious history. Forces working for the reform of Islam based in Africa itself were already at work.
Adamawa and Mahdism: the career of Hayatu ibn Sa'id in Adamawa, 1878–1898
Authors: Njeuma Martin Z.
Published: January 2009

The overthrow of the Sokoto empire at the beginning of this century was facilitated by the interplay of three major factors—the internal political situation of the empire which allowed too much autonomy to the constituent emirates, the rise of Mahdism in the eastern emirates, and European (British, French and German) competition leading to invasion. Each factor was a potential cause of instability, making the task of the invading forces much easier. This article is an attempt to examine the efforts of Hayatu ibn Sa'id, great grandson of Uthman dan Fodio, to transform latent feelings of expectations of the Mahdi in the Sokoto empire into a positive movement linked to the Sudanese Mahdiyya in the late nineteenth century. It also looks at the impact of Hayatu's activities on Adamawa.
The rubber trade of the Gold Coast and Asante in the nineteenth century: African innovation and market responsiveness
Authors: Dumett Raymond
Published: January 2009

The export trade in wild rubber occupies an important place in the nineteenth-century economic history of the Gold Coast and Asante, and the impetus which it gave to the future economic development of the country was greater than is commonly recognized. The timely development of this new product by African entrepreneurs and up-country producers in the 1880s enabled the colony to diversify its export bill at a time when flagging prices for palm products and dwindling supplies of ivory, monkey skins, and surface gold threatened economic stagnation. Between 1884 and 1898 Gold Coast rubber exports registered a twenty-five fold increase in volume, thereby placing the country among the top five rubber producers of the world.

An analysis of the Gold Coast rubber trade contributes to the demolition of certain myths concerning the economically passive role of West Africans in the development of their own hinterlands. European agencies—whether mercantile or governmental—contributed only indirectly to the development of the local rubber trade. No doubt the general protection and opportunity for exercise of individual initiative which the British colonial government provided enabled the Gold Coast to escape the excesses of forced labour and expropriation which marred European concessionaire rubber operations in other parts of Africa. But it was chiefly the myriads of African merchants, middlemen and producers who supplied the driving force of the local trade during the nineteenth century.

The rubber trade accelerated the pace of economic change in Asante and other interior states where the pull exerted by the sea-borne export sector previously had been minimal. It is clear that the number of people involved in trading generally—whether as middlemen or producers—increased greatly as a result of the lucrative returns to be gained from rubber tapping. With rubber trade expansion came a growing demand by producers for a wider range of European merchandise imports, plus the acceptance of a uniform metallic currency which facilitated market transactions throughout the interior. Finally, the profits saved from rubber tapping became an important source for indigenous capital investment in cocoa-farming, particularly in Asante.
New radiocarbon dates for Eastern and Southern Africa
Authors: Sutton J. E. G.
Published: January 2009

This article is a follow-up to that of Mr D. W. Phillipson published in this Journal in 1970, and to the six earlier lists compiled for the whole of sub-Saharan Africa by Dr B. M. Fagan. I have endeavoured to include here all radiocarbon dates for archaeological sites of the Iron Age and most of those of the end of the Stone Age in the eastern and southern part of Africa—that is from Ethiopia, the Upper Nile and the Congo Basin southward—which have been published or made available since the preparation of the former articles. Some of these dates are already included in recent numbers of the Journal Radiocarbon, or have been mentioned in publications elsewhere, as indicated in the footnotes. A large proportion of these new dates, however, have not yet been published, and are included here through the agreement of the various individual archaeologists and research bodies, all of whom I wish to thank for their cooperation. In particular, I am indebted to Mr David Phillipson for his willing assistance in providing a number of contacts and relaying information from southern Africa.
Archaeology in Benin
Authors: Connah Graham
Published: January 2009

Excavations and fieldwork in and around Benin City in the years 1961–4 have established the outlines of an archaeological sequence. This sequence is based on radiocarbon dates for stratified deposits, on a statistical examination of pottery form and decoration, and on datable European imports. The sequence suggested by the evidence extends from about the thirteenth century A.D. to the present time, although the survival of locally found ground stone axes in Benin ritual indicates that the area may well have been inhabited since Late Stone Age times. There is evidence for the artistic use of copper and its alloys from at least the thirteenth century onwards, but it is not known how long it had already been in use. Smithed and chased tin bronzes were found in a thirteenth-century context, whereas cast leaded brass was found in use in a nineteenth-century context. There is little evidence for lost-wax casting in Benin in early times. The writer suggests that future archaeological work should make the origins and early development of the city a priority.
The Daima Sequence and the Prehistoric Chronology of the Lake Chad Region of Nigeria
Authors: Connah Graham
Published: January 2009

An intensive archaeological field research programme conducted between 1963 and 1969 in the Lake Chad region of Nigeria has established the outlines of a prehistoric chronological sequence for the area. The excavations at Daima form the key to this sequence which also includes excavated evidence from Bornu 38, Kursakata, Shilma, Yau, Ajere and Birnin Gazargamo together with surface information from 70 other sites. Twenty radiocarbon dates indicate settlement of the area from the end of the second millennium B.C. (or the last quarter of the second millennium if the dates are corrected to calendar years) to the sixteenth or seventeenth century A.D. Evidence of occupation earlier than the second millennium B.C. may have to be sought in the highlands south of the lake area.

In the firki clay plains, south of the lake, it may be possible to trace the evolution of a Late Stone Age pastoralist economy into an Iron Age cereal cultivator economy. In the undulating sandy country, west of the lake, village settlements focused around the Yobe River seem to have developed, in response to external stimulus, the urban civilization which historical sources indicate at Birnin Gazargamo by the sixteenth century A.D. The contrasting environments designated ‘Firki’ and ‘Yobe’ had an important influence on the character of human settlement indicated by the archaeological evidence.

It is suggested that the prehistory of this region merits far greater attention than it has yet received and that the presence in this area of settlement mounds, with substantial depths of deposit, offers a wonderful opportunity for large-scale excavation programmes. Further surface investigations would also be justified, however, as the writer suspects that more prehistoric sites remain to be located in the area.
The General Strike in Zanzibar, 1948
Authors: Clayton Anthony
Published: January 2009

This article examines a three-week long strike in Zanzibar City in August and September 1948. The strike began among labourers from the mainland at work in Zanzibar port, but spread to all African work-people in the City after an unsuccessful attempt to break the strike by the government. This attempt had led to a major demonstration and confrontation at the entrance to the port, violence being only narrowly averted.

While at one level the strike was a Zanzibar sequel to the strikes of the previous year in Mombasa and Dar es Salaam, in Zanzibar there was additional significance in the fact that the City and Island's work-force were in very large proportion men from the East African mainland. Zanzibar's dependence on mainland labour had begun in the early decades of the twentieth century. In those years mainland labour had been particularly well-paid, by the standards of the time. By the late 1940s however, mainland labour in Zanzibar was as poor as, perhaps poorer than, its mainland counterparts. Besides, the political structure of the Protectorate aggravated sentiments of alienation since mainlanders were not regarded as permanent residents for whom the government should have any particular concern: nor were mainlanders represented in the legislature.

Even after the strike was over the colonial authorities saw only a need for labour reforms rather than political re-structuring to accommodate mainlanders. The strike however had briefly united all Africans, indigenous and mainlander. When, a decade later, this unity of Africans, mainlander and indigenous, town and plantation labourer and peasant, was re-formed, revolution followed. As a portent, therefore, Zanzibar's strike is of particular significance.
Alula, ‘The Son of Qubi’: a ‘King's Man’ in Ethiopia, 1875–1897
Authors: Erlich Haggai
Published: January 2009

Ras Alula played a significant role in the political history of northern Ethiopia during the period between the Egyptian invasion in 1875 and the Italian defeat at Adwa in 1896. Alula became well-known in Ethiopia and Europe for his role in shaping his country's relations with its African neighbours and with European powers. But his role in the internal history of Ethiopia was no less significant. This son of a peasant managed to avoid the restricted local agrarian social ladder by becoming the best general of the Tigrean emperor Yohannes IV (1872–89). As the ‘king's man’, Alula's power was based on his position in the court and on the province (Eritrea) over which he was appointed. But the leading Tigrean families rejected him. When Yohannes died and Eritrea was lost to the Italians, Alula became the most powerful champion of Tigrean independence from the new Shoan emperor, Menilek II. A Tigrean court seemed to be his only opportunity to maintain his position of a ‘king's man’, without which he would have to return to the local agrarian social ladder. After four years of resistance to the new Shoan hegemony, Alula submitted to Menilek and was rewarded with the long-desired position of ‘the king's man’. His recognition of Menilek may be regarded as a fatal blow to Tigrean independence.