bluuebunny/crossref_metadata_2025 huggingface dataset:
Facile preparation and characterization of novel fluoroalkyl end‐capped oligomer/zinc oxide nanocomposites
Authors: Sasazawa Kazuo , Hirayama Yutarou , Sawada Hideo
Published: December 2008

BACKGROUND: The aim of the present work was to prepare novel fluoroalkyl end‐capped oligomer/zinc oxide nanocomposites by the use of fluoroalkyl end‐capped oligomers as key intermediates. In addition, it was intended to clarify the unique properties of these fluorinated nanocomposites.

RESULTS: A variety of fluoroalkyl end‐capped oligomer/zinc oxide nanocomposites were prepared by the interaction of the corresponding oligomers with zinc oxide particles, which were obtained by the reaction of zinc acetate dihydrate with sodium hydroxide in ethanol solution at room temperature. In contrast, fluoroalkyl end‐capped 2‐methacryolyoxyethanesulfonic acid oligomer was found to afford the corresponding fluorinated amorphous zinc oxide composites under similar conditions.

CONCLUSION: These fluorinated zinc oxide composites thus obtained are nanometer size‐controlled very fine particles, and they exhibit a good dispersibility and stability in water and traditional organic media. These fluorinated nanocomposites were also applied for the surface modification of poly(methyl methacrylate) (PMMA) films, which gave not only a good surface‐active property imparted by fluorine but also unique characteristics related to the presence of zinc oxide nanoparticles on the modified PMMA film surface. Copyright © 2008 Society of Chemical Industry
Solar cell efficiency tables (version 33)
Authors: Green Martin A. , Emery Keith , Hishikawa Yoshihiro , Warta Wilhelm
Published: December 2008

Consolidated tables showing an extensive listing of the highest independently confirmed efficiencies for solar cells and modules are presented. Guidelines for inclusion of results into these tables are outlined and new entries since July 2008 are reviewed. Efficiencies are updated to the new reference solar spectrum tabulated in IEC 60904‐3 Ed. 2 revised in April 2008 and an updated list of recognised test centres is also included. Copyright © 2008 John Wiley & Sons, Ltd.
5th BSPR‐EBI Meeting, Proteomics: From Technology to New Biology 8–10 July 2008, Wellcome Trust Conference Centre, Hinxton, Cambridge, UK
Authors: English Jane A. , Polden Julie , Robinson Aisling A.
Published: December 2008

This paper reports on the 5th joint British Society for Proteome Research (BSPR) and European Bioinformatics Institute (EBI) meeting which took place at the Wellcome Trust Conference Centre, Cambridge, UK, from the 8th to 10th July, 2008. As in previous years, the meeting attracted leading experts in the field who presented the latest cutting edge in proteomics. The meeting was entitled “Proteomics: From Technology to New Biology” taking into account the major transition proteomics has undergone in the past few years. In particular, the use of multiple reaction monitoring (MRM)‐based targeted experiments for absolute quantification and validation of proteins was the hot topic of the meeting. Attended by some 250 delegates, the conference was extremely well organised and provided a great opportunity for discussion and initiation of new collaborations.
Synthesis and characterization of postsulfonated poly(arylene ether sulfone) diblock copolymers for proton exchange membranes
Authors: Takamuku Shogo , Akizuki Ken , Abe Mitsutaka , Kanesaka Hiroyuki
Published: December 2008

Sulfonated poly(arylene ether sulfone) diblock copolymers were studied through the postsulfonation process. Two kinds of hydrophobic oligomers with a molecular weight of 20 kDa were prepared in advance as block sequences and then coupled together to obtain diblock copolymers. One oligomer was synthesized from bis(4‐hydroxyphenyl) sulfone (BHPS) and 4,4′‐difluorodiphenyl sulfone (DFDPS), which was thought to be incapable of postsulfonation. The other oligomer was synthesized from hydroquinone (HQ) and 4,4′‐dichlorodiphenyl sulfone (DCDPS), which successfully proceeded to a hydrophilic sequence as a result of sulfonation onto the HQ moiety after the coupling reaction. Consequently, a diblock copolymer with high molecular weight was obtained; although its intrinsic viscosity was too low to form a tough membrane because of its high rigidity and high crystallinity. Therefore, the use of decafluorobiphenyl (10F) as a termination reagent was investigated with the aim of achieving higher coupling reactivity and a kinky property. As a result, a sulfonated diblock copolymer was successfully obtained with sufficient molecular weight and intrinsic viscosity to form the membrane, as well as with adequate thermal properties. It was observed that proton conductivity, water uptake, and the water diffusion coefficient increased with higher ion exchange capacity. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 700–712, 2009
Ethylene polymerization by the new chromium catalysts based on amino‐pyrrolide ligands
Authors: He Li‐Peng , Liu Jing‐Yu , Pan Li , Wu Ji‐Qian , Xu Bao‐Chang , Li Yue‐Sheng
Published: December 2008

A series of amino‐pyrrolide ligands (1–4a) and their derivatives amino‐thiophene ligand (5a), amino‐indole ligand (6a) were prepared. Chromium catalysts, which were generated in situ by mixing the ligands with CrCl3(thf)3 in toluene, were tested for ethylene polymerization. The preliminary screening results revealed that the tridentate amino‐pyrrolide ligands containing soft pendant donor, 3a, 4a/CrCl3(thf)3 systems displayed high catalytic activities towards ethylene polymerization in the presence of modified methyaluminoxane. The electronic and steric factors attached to the ligand backbone significantly affected both the catalyst activity and the polymer molecular weight. Complex 4b was obtained by the reaction of CrCl3(thf)3 with one equivalent of the lithium salts of 4a, which was the most efficient ligand among the tested ones. The effect of polymerization parameters such as cocatalyst concentration, ethylene pressure, reaction temperature, and time on polymerization behavior were investigated in detail. The resulting polymer obtained by 4b display wax‐like and possess linear structure, low molecular weight, and unimodal distribution. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 713–721, 2009
Synthesis and micellization of PSt‐PNIPAM‐PDMAEMA hetero‐arm star polymer with double thermo‐responsibility
Authors: Li Jian , He Wei‐Dong , Han Shou‐chen , Sun Xiao‐li , Li Li‐ying , Zhang Bo‐yu
Published: December 2008

A hetero‐arm star polymer, polystyrene‐poly(N‐isopropylacrylamide)‐ poly(2‐(dimethylamino)ethylmethacrylate) (PSt‐PNIPAM‐PDMAEMA), was synthesized by “clicking” the alkyne group at the junction of PSt‐b‐PNIPAM diblock copolymer onto the azide end‐group of PDMAEMA homopolymer via 1,3‐dipolar cycloaddition. The resultant polymer was characterized by gel permeation chromatography, proton nuclear magnetic resonance spectroscopy and Fourier transform infrared spectroscopy. PSt‐PNIPAM‐PDMAEMA micelles with PSt block as core and PNIPAM and PDMAEMA blocks as shell were formed when adding the copolymer solution in THF into 10 folds of water. Lower critical solution temperature (LCST) of PNIPAM and PDMAEMA homopolymer is 32 °C for PNIPAM and 40 to 50 °C for PDMAEMA, respectively. Upon continuous heating through their LCSTs, PSt‐PNIPAM‐PDMAEMA core‐shell micelles exhibited two‐stage thermally induced collapse. The first‐stage collapse, from 20 to 34 °C, is ascribed to the shrinkage of PNIPAM chains; and the second‐stage collapse, from 38 to 50 °C, is due to the shrinkage of PDMAEMA chains. Dynamic light scattering was used to confirm the double phase transitions. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 786–796, 2009
Synthesis, characterization, and thermally activated curing of oligosiloxanes containing benzoxazine moieties in the main chain
Authors: Kiskan Baris , Aydogan Binnur , Yagci Yusuf
Published: December 2008

Oligosiloxanes containing thermally curable benzoxazine units in the main chain have been synthesized. For this purpose, first the diallyl functional monomer is synthesized through the Mannich and ring closing reaction of 4,4′‐isopropylidenediphenol (bisphenol A), formaldehyde and allylamine. Hydrosilylation reaction of the resulting diallylic monomer (B‐ala) with 1,1,3,3‐tetramethyldisiloxane (TMDS) in the presence of Pt catalyst yields the corresponding poly(B‐ala‐tetramethyl disiloxane)s (PBTMDS) with the molecular weights in the range of 1800–4100 Da. The structures of the precursor diallyl monomer and the resulting polymers are confirmed by FT‐IR and 1H NMR analysis. Curing behavior of both the monomer and polymers has also been studied by Differential Scanning Calorimetry (DSC). Flexible free standing transparent films of the oligosiloxanes are obtained by solvent casting from dichloromethane solution on Teflon plates. The films preserve shape and, to some extent, toughness after thermal curing between 100 and 180 °C. Thermal properties of the cured polymers are also investigated by thermogravimetric analysis (TGA). © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 804–811, 2009
Behavioral therapy intervention trial to improve sleep quality and cancer‐related fatigue
Authors: Berger Ann M. , Kuhn Brett R. , Farr Lynne A. , Lynch James C. , Agrawal Sangeeta , Chamberlain Julie , Von Essen Susanna G.
Published: December 2008

Background: To determine whether sleep quality and fatigue associated with breast cancer adjuvant chemotherapy treatments can be improved with behavioral therapy (BT) [Individualized Sleep Promotion Plan (ISPP©)] including modified stimulus control, modified sleep restriction, relaxation therapy, and sleep hygiene.

Methods: Randomized‐controlled trial based on Piper Integrated Fatigue Model, 219 stages I–IIIA breast cancer patients. Prior to the initial chemotherapy treatment, BT participants developed an ISPP plan that was regularly reinforced and revised. Controls received healthy eating information and attention. Pittsburgh Sleep Quality Index (PSQI), daily diary, actigraph, and Piper Fatigue Scale (PFS) data were collected 2 days prior, during the 7 days after each treatment, and 30 days after the last treatment. Repeated measures analysis of variance was used.

Results: Prior to chemotherapy, participants reported mild fatigue and fairly poor sleep quality. All variables changed over time. A group by time interaction was found for sleep quality (PSQI) improving in the BT group. Diary revealed group differences on number of awakenings, minutes awake after sleep onset, and sleep efficiency. Fatigue (PFS) was similar between groups.

Conclusions: The BT group showed improved sleep quality over time and better sleep (diary). Perceptions of improved sleep quality over time are not consistently associated with diary or actigraph, or result in lower fatigue. Copyright © 2008 John Wiley & Sons, Ltd.
The influence of acculturation and breast cancer‐specific distress on perceived barriers to genetic testing for breast cancer among women of African descent
Authors: Sussner Katarina M. , Thompson Hayley S. , Jandorf Lina , Edwards Tiffany A. , Forman Andrea , Brown Karen , Kapil‐Pair Nidhi , Bovbjerg Dana H. , Schwartz Marc D. , Valdimarsdottir Heiddis B.
Published: December 2008

Objective: Rising health disparities are increasingly evident in relation to use of genetic services (including genetic counseling and testing) for breast cancer risk, with women of African descent less likely to use genetic services compared with Whites. Meanwhile, little is known regarding potential within‐group acculturation and psychological differences underlying perceived barriers to genetic testing among women of African descent.

Methods: Hypothesized contributions of acculturation factors and breast cancer‐specific distress to perceived barriers to genetic testing were examined with a statistical analysis of baseline data from 146 women of African descent (56% US born and 44% foreign born) meeting genetic breast cancer risk criteria and participating in a larger longitudinal study that included the opportunity for free genetic counseling and testing. Perceived barriers assessed included: (1) anticipation of negative emotional reactions, (2) stigma, (3) confidentiality concerns, (4) family‐related worry, and (5) family‐related guilt associated with genetic testing.

Results: In multivariate analyses, being foreign born was a significant predictor of anticipated negative emotional reactions about genetic testing (β=0.26; SE=0.11; p=0.01). Breast cancer‐specific distress scores (avoidance symptoms) were positively related to anticipated negative emotional reactions (β=0.02; SE=0.005; p=<0.0001), confidentiality concerns (β=0.02; SE=0.01; p=0.02), and family‐related guilt (β=0.02; SE=0.01; p=0.0009) associated with genetic testing.

Conclusions: Results suggest an influence of acculturation and breast cancer‐specific distress on perceived barriers to genetic testing among women of African descent. The potential utility of culturally tailored genetic counseling services taking into account such influences and addressing emotional and psychological concerns of women considering genetic testing for breast cancer should be investigated. Copyright © 2008 John Wiley & Sons, Ltd.
Kinetics of Thermal Decomposition of Ammonium Perchlorate with Nanocrystals of Binary Transition Metal Ferrites
Authors: Singh Gurdip , Kapoor Inder Pal Singh , Dubey Shalini , Siril Prem Felix
Published: December 2008

This article was published in Early View with DOI 10.1002/prep.200800017 – what is wrong. It has appeared with the correct DOI 10.1002/prep.200900017 – in Propellants, Explosives, Pyrotechnics 2009 (34) issue 1/2009 on pp 78‐83.
Sublethal effects of spinosad on survival, growth and reproduction of Helicoverpa armigera (Lepidoptera: Noctuidae)
Authors: Wang Dong , Gong Peiyu , Li Mei , Qiu Xinghui , Wang Kaiyun
Published: December 2008

BACKGROUND: Helicoverpa armigera (Hübner) is one of the most important pests in many countries. Spinosad is used widely for the control of pests, but there is sparse information available regarding its sublethal effects on H. armigera. Here, the authors attempt to investigate the sublethal effects of spinosad on H. armigera in order to reveal the negative, non‐lethal impact of insecticides on this pest.

RESULTS: The toxicity of spinosad against H. armigera was determined under laboratory conditions by oral exposure of late second‐instar larvae to the compound. The 48 h LC50 and 72 h LC50 values of spinosad to this pest were found to be 0.41 mg kg−1 and 0.35 mg kg−1 respectively. Spinosad at sublethal concentrations significantly extended the developmental time of survivor larvae, and reduced larval wet weight. Post‐exposure effects were indicated by decreased pupation ratio and pupal weight, by prolonged prepupal and pupal periods and by decreased emergence ratio, fecundity and longevity of adults.

CONCLUSION: These results suggest that the combination of lethal and sublethal effects of spinosad might affect pest population dynamics significantly by decreasing its survival and reproduction, and by delaying its development. Copyright © 2008 Society of Chemical Industry
Coactivity of sulfide ingredients: a new perspective of the larvicidal activity of garlic essential oil against mosquitoes
Authors: Kimbaris Athanasios C , Kioulos Elias , Koliopoulos George , Polissiou Moschos G , Michaelakis Antonios
Published: December 2008

BACKGROUND: The activity of several garlic oil ingredients against Culex pipiens L. larvae was studied. In addition to diallyl sulfide (DS) and diallyl disulfide (DDS), the garlic oils used included one essential oil (EO) and two semi‐synthetic garlic essential oils (SSGEO1 and SSGEO2), which resulted from the enrichment of EO with DS and DDS standards respectively. The oils were compared with respect to their toxicity.

RESULTS: The chemical composition of the tested oils was evaluated by means of gas chromatography–mass spectrometry. Experimental data from the tested samples revealed high toxicity. In detail, DDS (6.09 mg L−1) was the most active, followed by SSGEO2 (7.05 mg L−1) and EO (8.01 mg L−1), while SSGEO1 and DS were relatively inactive.

CONCLUSION: The addition of DDS to EO did not change the toxic effect of the essential oil, whereas the presence of DS in excess produced an enriched essential oil with low toxicity. Furthermore, the antagonistic effect of DS and DDS against the other components of EO was shown by the application of two equations obtained from the literature. Their larvicidal performances were correlated, for the first time, with their detailed chemical composition. Data analysis strongly indicated the toxicity of the other EO sulfur ingredients. Copyright © 2008 Society of Chemical Industry
Field evaluations of insecticide treatment regimens for control of the common bed bug, Cimex lectularius (L.)
Authors: Moore David J , Miller Dini M
Published: December 2008

BACKGROUND: Because bedbugs, Cimex lectularius L., have not been a problem in the USA for over 40 years, few insecticide products are labeled for their control. Most products that are labeled for bedbugs are pyrethroids. However, recent studies indicate that field‐collected bedbugs may be resistant to pyrethroids. There are also non‐pyrethroid products labeled for bedbugs, but, like the pyrethroids, none of these products has been evaluated for field efficacy. This study evaluated the efficacy of two insecticide treatment regimens for bedbugs in multi‐unit housing. Both of the treatments included multiple products currently being used by the pest management industry.

RESULTS: The ‘traditional’ treatment consisted of applications of pyrethroid products and an insect growth regulator. The ‘novel’ treatment consisted of applications of non‐pyrethroid products. The traditional treatment significantly reduced the number of bedbugs from 39.8 ± 10.1 per unit prior to treatment to 2.2 ± 1.0 at the end of the test period (P = 0.02; 95% reduction). The number of live bedbugs in the ‘novel’ treatment was also significantly reduced from 71.4 ± 25.3 bedbugs per unit to 10.2 ± 4.4 after 8 weeks (86% population reduction).

CONCLUSIONS: Although both treatment regimens reduced bedbug numbers, the fact that bedbugs were not eliminated after multiple applications suggests that the insecticides, applied at the current label rates, were inadequate. These results suggest that a more integrated approach to bedbug control is necessary in multi‐unit housing situations. Copyright © 2008 Society of Chemical Industry
Toxicity of δ‐phenothrin and resmethrin to non‐target insects
Authors: Antwi Frank B , Peterson Robert KD
Published: December 2008

BACKGROUND: The susceptibility of adult house cricket, Acheta domesticus (L.), adult convergent lady beetle, Hippodamia convergens (Guérin‐Méneville), and larval fall armyworm, Spodoptera frugiperda (JE Smith), to resmethrin and δ‐phenothrin synergized with piperonyl butoxide (PBO) was evaluated in a laboratory bioassay procedure.

RESULTS: The 1 day LC50 values for resmethrin + PBO were 23.2, 32.08 and 307.18 ng cm−2 for A. domesticus, H. convergens and S. frugiperda respectively. The 1 day LC50 values for δ‐phenothrin + PBO were 26.9, 74.91 and 228.57 ng cm−2 for A. domesticus, H. convergens and S. frugiperda respectively. The regression relationship between species mortality and concentration explained 51–81% of the variation for resmethrin + PBO and 72–97% of the variation for δ‐phenothrin + PBO. The LC50 values decreased with time for these insecticides for all surrogate species. In terms of sensitivities among the insects to resmethrin + PBO and δ‐phenothrin + PBO, A. domesticus was most sensitive, followed by H. convergens and then S. frugiperda.

CONCLUSION: The results indicate that resmethrin + PBO was generally more toxic than δ‐phenothrin + PBO. Based on the results, A. domesticus seems to be a good surrogate species for estimating potential non‐target terrestrial insect impacts from exposure to pyrethroids used in public health applications. Copyright © 2008 Society of Chemical Industry
Toxicity of emamectin benzoate to Cydia pomonella (L.) and Cydia molesta (Busck) (Lepidoptera: Tortricidae): laboratory and field tests
Authors: Ioriatti Claudio , Anfora Gianfranco , Angeli Gino , Civolani Stefano , Schmidt Silvia , Pasqualini Edison
Published: December 2008

BACKGROUND: Emamectin benzoate is a novel macrocyclic lactone insecticide derived from naturally occurring avermectin molecules isolated by fermentation from the soil microorganism Streptomyces avermitilis Kim & Goodfellow. The present study aims to evaluate the toxicity of emamectin benzoate to codling moth, Cydia pomonella (L.), and oriental fruit moth, C. molesta (Busck), under laboratory and semi‐field conditions.

RESULTS: Dose response bioassays showed that emamectin benzoate had a high level of intrinsic toxicity to early‐stage larvae of both species, and that contact activity might contribute significantly to mortality. In the semi‐field trials, residual toxicity lasted for more than 1 week. Ovicidal activity was recorded only for C. pomonella (approximately 30%), irrespective of the concentrations tested. Field trials confirmed the efficacy of emamectin benzoate on codling moth when applied at 7 day intervals. Fruit damage, both from the first and second generations, was comparable with that on treatment with chlorpyrifos‐ethyl, used as a chemical reference.

CONCLUSION: Emamectin benzoate may be considered a valuable tool for the control of codling moth as a component of an IPM programme. Its collective advantages are: high efficacy, lack of cross‐resistance with currently used products, control of secondary pests such as oriental fruit moth and selective toxicity that spares beneficials. Copyright © 2008 Society of Chemical Industry
Interplaying factors for the formation of photoswitchable β‐hairpins: the advantage of a flexible switch
Authors: Varedian Miranda , Erdélyi Máté , Persson Åsa , Gogoll Adolf
Published: December 2008

A series of peptidomimetics intended to promote the β‐hairpin motif have been studied. Structural variations include a turn region with and without a photoswitchable chromophore, and strands with amino acid side chains supporting various degrees of interstrand interactions for hairpin stabilisation. The propensity of the compounds to form β‐hairpins was evaluated experimentally by NMR spectroscopy, translational self‐diffusion studies and CD spectroscopy. In the presence of hairpin stabilising interstrand interactions, the structurally flexible stilbene chromophore appeared to be well compatible with the imposed secondary structure. Copyright © 2008 European Peptide Society and John Wiley & Sons, Ltd.
Do open‐ended survey questions on migration motives create coder variability problems?
Authors: Niedomysl Thomas , Malmberg Bo
Published: December 2008

Contemporary research on migration has benefited from adopting a variety of methodological approaches and different sources of information to provide answers to the ever‐recurring question of why people migrate. Yet, when it comes to central methods used for researching migration motives, progress appears to have been slow. This paper focuses on surveys to research migration motives using self‐administered postal questionnaires. It addresses a key validity question, namely the issue of whether the usage of open‐ended questions creates coder variability problems. An experimental research design was used where five coders independently coded 500 randomly selected responses from a large survey on migration motives. Krippendorff's α was calculated to test the level of agreement between the coders. The results advance our knowledge in two important ways: firstly, it is shown that coder variability is not a major problem (Krippendorff's α = 0.82). Secondly, it identifies those types of responses that nevertheless appear problematic to code. The implications of these findings for survey research on migration motives are discussed, and it is argued that open‐ended questions have some distinct advantages compared with the more commonly used closed‐ended questions. Copyright © 2009 John Wiley & Sons, Ltd.
Attractive vicinities
Authors: Li Wenjuan , Holm Einar , Lindgren Urban
Published: December 2008

This paper examines the significance of spatial and socioeconomic factors in determining place attractiveness, and it suggests an explorative method for the analysis of detailed patterns of spatial attractiveness. By departing from a simple spatial model that distinguishes between different hinterlands at varying distances from the individuals' immediate neighbourhood, we analyse the relative importance of demographic, labour‐market, service as well as physical factors for income levels and in‐migration rates. Based on a longitudinal spatially referenced micro‐database covering over 100 annual attributes per individual and digital land‐use information for the entire territory, vicinity characteristics were calculated for every populated square kilometre (108,000 squares). Regression, a partial F test andη2were used to decompose explained variation in attractiveness into indicators classified in socioeconomic categories and spatial ranges. The findings indicate a considerable variation across the spatial scale. For example, the characteristics of the vicinity (km2) seem to have a much larger influence on variation in place attractiveness than the characteristics of the hinterland (within 5 to 50 km). Moreover, place attractiveness seems to be determined to a very small extent by physical factors in the immediate vicinity. Demographic and socioeconomic factors appear to be the main determinants of place attractiveness. Copyright © 2009 John Wiley & Sons, Ltd.
The 1995–2000 interprefectural migration of foreign residents of Japan: salient features and multivariate explanation
Authors: Ishikawa Yoshitaka , Liaw Kao‐Lee
Published: December 2008

Taking advantage of large samples from the 2000 census, this paper attempts (1) to identify the salient features of the 1995–2000 interprefectural migration of foreign residents in Japan; and (2) to carry out a multivariate explanation of this migration process by using a nested logit model which consists of a departure submodel at the upper level and a destination choice submodel at the lower level. Our main findings are as follows. Firstly, the migration process differed markedly between foreign residents and native Japanese. Secondly, the interprefectural migration process of the foreign residents was highly selective with respect to both ethnicity and educational attainment. Thirdly, the effects of labour‐market factors, co‐ethnic attraction and marital opportunities in the destination choice submodel conformed to expectations. Finally, the strong displacement effect of new immigrants in the departure submodel suggests that the foreign residents were competing with each other for rather limited economic opportunities in Japan. Copyright © 2009 John Wiley & Sons, Ltd.
Coherent control of ground state excitons in the nonlinear regime within an ensemble of self‐assembled InAs quantum dots
Authors: Moldaschl Thomas , Müller Thomas , Golka Sebastian , Parz Wolfgang , Strasser Gottfried , Unterrainer Karl
Published: December 2008

In this work femtosecond spectral hole burning spectroscopy is used to resonantly excite ground state excitons in an ensemble of self‐assembled InAs/GaAs quantum dots with a strong pump pulse. Two fundamental coherent nonlinear effects are observed with the aid of the intrinsic time‐ and frequency resolution of the setup: The low temperature Rabi oscillation of the two‐level system associated with the excitonic ground state transition and the observation of two‐photon absorption in the surrounding GaAs crystal matrix. The emergence of the latter effect also infers the existence of charged excitons in the nominally undoped QD sample, backed up by the observation of additional spectral holes next to the excitonic transitions. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Electron states in CdMnSe/ZnSe and in CdSe/ZnMnSe diluted magnetic semiconductor quantum dots
Authors: Triki M. , Afia S. Ben , Jaziri S.
Published: December 2008

Self‐assembed quantum dots (QDs) based on II‐VI compounds are interesting with regard to their electronic and optical properties due to their large scale provided by their fundamental gap. Among II‐VI materials, diluted magnetic semiconductor (DMS) nanostructures like CdSe/ZnMnSe and CdMnSe/ZnSe QDs are of particular interest due to the exchange interaction between the spin of the carriers and the spin of the paramagnetic Mn2+ ions located in ternary alloy layers. The application of an external magnetic field at low temperature induce the so‐called giant Zeemann effect of the band edges. In this work we first report the band offset calculations for zinc blende pseudomorphically strained CdSe/ZnSe interface. Then, we calculate the lowest electron states in both (Cd,Mn)Se/ZnSe and in CdSe/(Zn,Mn)Se QDs. Results show that the giant Zeeman splitting is more important when the Mn ions are inside the dot. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Theoretical analysis of modal gain in p‐doped 1.3 μm InAs/GaAs quantum dot lasers
Authors: Ji Hai‐Ming , Yang Tao , Cao Yu‐Lian , Ma Wen‐Quan , Cao Qing , Chen Liang‐Hui
Published: December 2008

A theoretical study of modal gain in p‐doped 1.3 μm InAs/GaAs quantum dot (QD) lasers is presented. The expression of modal gain is derived, which includes an effective ratio that describes how many QDs contribute to the modal gain. The calculated results indicate that the modal gain with the effective ratio is much smaller than that without the effective ratio. The calculated maximum modal gain is in a good agreement with the experimental data. Furthermore, QDs with lower height or smaller aspect ratio are beneficial in achieving a larger maximum modal gain that leads to lower threshold current density and higher differential modal gain. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Modulation of tropical convection by breaking Rossby waves
Authors: Allen G. , Vaughan G. , Brunner D. , T. May P. , Heyes W. , Minnis P. , K. Ayers J.
Published: December 2008

This work discusses observations of both the convective‐inhibiting and convective‐promoting properties associated with Rossby waves that break in the extratropics and extend into the tropics. Two tropical drought periods—times of reduced tropical cloudiness and rainfall—were observed during mid to late November 2005 over a wide area of north‐west Australia, with an observed eruption of a nearby synoptic tropical cloud band in between times. Both convective inhibition and promotion appear to be linked to the descent of dry upper tropospheric air within a series of tropopause folds; convective inhibition was observed within the dry pool itself, whilst convective promotion was observed on the high moisture gradient at the leading edge of an advancing dry slot. A range of satellite images, surface rain gauges, radiosonde and ozonesonde data are used in conjunction with back trajectories and European Centre for Medium‐Range Weather Forecasts (ECMWF) analysis fields to investigate the origins and dynamics associated with these convective events, showing each to be ultimately linked to breaking Rossby wave activity on the southern subtropical jet. Together, these observations support a growing number of studies linking midlatitude tropopause‐level dynamics with the modulation of tropical deep convection, an influence that is poorly characterized when considering the climatology of tropical cloudiness and rainfall. Copyright © 2008 Royal Meteorological Society
Weight interpolation for efficient data assimilation with the Local Ensemble Transform Kalman Filter
Authors: Yang Shu‐Chih , Kalnay Eugenia , Hunt Brian , E. Bowler Neill
Published: December 2008

We have investigated a method to substantially reduce the analysis computations within the Local Ensemble Transform Kalman Filter (LETKF) framework. Instead of computing the LETKF analysis at every model grid point, we compute the analysis on a coarser grid and interpolate onto a high‐resolution grid by interpolating the analysis weights of the ensemble forecast members derived from the LETKF.

Because the weights vary on larger scales than the analysis increments, there is little degradation in the quality of the weight‐interpolated analyses compared to the analyses derived with the high‐resolution grid. The weight‐interpolated analyses are more accurate than the ones derived by interpolating the analysis increments. Additional benefit from the weight‐interpolation method includes improving the analysis accuracy in the data‐void regions, where the standard LEKTF with the high‐resolution grid gives no analysis corrections due to a lack of available observations. Copyright © Royal Meteorological Society and Crown Copyright, 2008
A multirange architecture for collision‐free off‐road robot navigation
Authors: Sermanet Pierre , Hadsell Raia , Scoffier Marco , Grimes Matt , Ben Jan , Erkan Ayse , Crudele Chris , Miller Urs , LeCun Yann
Published: December 2008

We present a multilayered mapping, planning, and command execution system developed and tested on the LAGR mobile robot. Key to robust performance under uncertainty is the combination of a short‐range perception system operating at high frame rate and low resolution and a long‐range, adaptive vision system operating at lower frame rate and higher resolution. The short‐range module performs local planning and obstacle avoidance with fast reaction times, whereas the long‐range module performs strategic visual planning. Probabilistic traversability labels provided by the perception modules are combined and accumulated into a robot‐centered hyperbolic‐polar map with a 200‐m effective range. Instead of using a dynamical model of the robot for short‐range planning, the system uses a large lookup table of physically possible trajectory segments recorded on the robot in a wide variety of driving conditions. Localization is performed using a combination of global positioning system, wheel odometry, inertial measurement unit, and a high‐speed, low‐complexity rotational visual odometry module. The end‐to‐end system was developed and tested on the LAGR mobile robot and was verified in independent government tests. © 2008 Wiley Periodicals, Inc.
Depth versus breadth: How content coverage in high school science courses relates to later success in college science coursework
Authors: Schwartz Marc S. , Sadler Philip M. , Sonnert Gerhard , Tai Robert H.
Published: December 2008

This study relates the performance of college students in introductory science courses to the amount of content covered in their high school science courses. The sample includes 8310 students in introductory biology, chemistry, or physics courses in 55 randomly chosen U.S. colleges and universities. Students who reported covering at least 1 major topic in depth, for a month or longer, in high school were found to earn higher grades in college science than did students who reported no coverage in depth. Students reporting breadth in their high school course, covering all major topics, did not appear to have any advantage in chemistry or physics and a significant disadvantage in biology. Care was taken to account for significant covariates: socioeconomic variables, English and mathematics proficiency, and rigor of their preparatory high science course. Alternative operationalizations of depth and breadth variables result in very similar findings. We conclude that teachers should use their judgment to reduce coverage in high school science courses and aim for mastery by extending at least 1 topic in depth over an extended period of time. © 2008 Wiley Periodicals, Inc. Sci Ed 93:798–826, 2009
Alignment between the physics content standard and the standardized test: A comparison among the United States‐New York State, Singapore, and China‐Jiangsu
Authors: Liu Xiufeng , Zhang Baohui , Liang Ling L. , Fulmer Gavin , Kim Beaumie , Yuan Haiquan
Published: December 2008

Alignment between content standards and standardized tests is a significant issue to society, science pedagogy, and test validation. To better understand the issues related to alignment, this study compares the alignment in physics among three education systems: Jiangsu (China), New York State (United States), and Singapore. The same coding framework for content standards and standardized tests is used to compute the alignment indices in the three education systems. It was found that there was a statistically significant alignment between the New York content standard and the standardized test for physics, but there was not a statistically significant alignment for Chinese and Singapore physics. The insignificant alignment for Chinese and Singapore physics was due to a shift toward higher level cognitive reasoning skills from content standards to standardized tests. For Chinese physics, the insignificant alignment was also due to a heavier emphasis on electricity in the test than in the content standard. Both significant and insignificant alignments may result in desirable and undesirable effects on guiding classroom instruction. Thus, ongoing study of the alignment between a science content standard and the standardized test is necessary for any education system, and alignment studies may be used as a means of teacher professional development for improving student achievement. © 2008 Wiley Periodicals, Inc. Sci Ed 93:777–797, 2009
The association between stress, self‐esteem and childhood acceptance in nursing and pharmacy students: a comparative cross‐cultural analysis
Authors: Mimura Chizu , Murrells Trevor , Griffiths Peter
Published: December 2008

The proposition that stress level is affected by self‐esteem development, for which acceptance from others in childhood is a key issue, was tested in two health care professions. The sample was 131 from nursing studies and 91 from pharmacy studies at a university in London, and 344 from nursing and 976 from pharmacy in Tokyo. Levels of stress were measured with the Perceived Stress Scale, self‐esteem with the Rosenberg Self‐Esteem Scale and childhood acceptance with the Parental Nurturance Scale. The data were analysed in terms of levels of and causal path between stress, self‐esteem and childhood acceptance. The proposed mechanism was supported among the nursing and pharmacy students in both British and Japanese cultures. The sample was also found to be substantially high on stress and low on self‐esteem and childhood acceptance. The results suggested that those entering the health care profession, such as nursing and pharmacy, have some additional vulnerability to stress compared with the general population. Enhancing self‐esteem was strongly recommended in stress management for health care professions. Copyright © 2008 John Wiley & Sons, Ltd.
Have you facebooked Astin lately? Using technology to increase student involvement
Authors: Heiberger Greg , Harper Ruth
Published: December 2008

This chapter explores Facebook.com's current and potential uses for increasing college student involvement. Ideas based on Astin's model of student involvement provide a framework for discussion.
Blogging in the academy
Authors: Nackerud Shane , Scaletta Kurtis
Published: December 2008

This chapter discusses the use of blogs in higher education, including how students and instructors use blogs, the value of blogs in this setting, and privacy and security implications. The chapter also features an examination of the University of Minnesota's UThink blogging system.
The social foundation of team‐based learning: Students accountable to students
Authors: Sweet Michael , Pelton‐Sweet Laura M.
Published: December 2008

Members of a group consider themselves mostly accountable to an external authority, while members of a team also hold themselves and each other accountable. In moments of contribution and accountability, discussions of course material in the TBL classroom acquire a remarkable emotional charge.
Teaching skills for facilitating team‐based learning
Authors: Lane Derek R.
Published: December 2008

This chapter describes the teaching competencies, facilitation strategies, and personal characteristics that minimize student frustration, increase the fidelity of TBL implementation, and ultimately moderate student success.
Peer assessment and evaluation in team‐based learning
Authors: Cestone Christina M. , Levine Ruth E. , Lane Derek R.
Published: December 2008

This chapter discusses the merits of peer assessment and evaluation; the instructional guidelines, issues, and considerations for their use in the TBL classroom, and a brief description of peer assessment methods and information on how to access forms.
Technological alternatives to paper‐based components of team‐based learning
Authors: Robinson Daniel H. , Walker Joshua D.
Published: December 2008

The purpose of instructional technology is to make things possible that are otherwise not, or to make easier things that otherwise are difficult. This chapter describes a few of the tweaks to team‐based learning that the authors have developed using technology.
The biology, ecology and economic importance of the pink scavenger caterpillar Pyroderces rileyi (Lepidoptera: Cosmopterigidae) on banana in Jamaica
Authors: Garraway E , Henry DC , Critchley BR
Published: December 2008

The pink scavenger caterpillar Pyroderces rileyi Walsingham (Lepidoptera: Cosmopterigidae) is a recent pest of bananas in Jamaica. The larval faecal pellets result in scarring of the banana fruit. The pest occurs on several crops, including cotton, sorghum and maize, across the world. Its biology in Jamaica, food plant preferences and impact of the recommended control method are examined. Adult trapping methods are investigated. Development from egg to adult took an average of approximately 37 days. The number of larvae increases with the age of the bunch, probably due to decreased amounts of latex as the bunch matures. Adult male moths were caught using traps baited with (E)‐11‐tetradecenyl acetate as a pheromone lure. Pheromone lures based on a related species, P. simplex Walsingham, were tested but a second minor (< 10%) component, (E)‐11‐tetradecen‐1‐ol, present in P. simplex did not appreciably enhance the attractancy of the acetate component. Deflowering was effective as a control measure, significantly reducing adult numbers as well as the level of scarring. Copyright © 2008 John Wiley & Sons, Ltd
Oxidation Stability of Virgin Olive Oils from Some Important Cultivars in East Mediterranean Area in Turkey
Authors: Kıralan Mustafa , Bayrak Ali , Özkaya Mücahit Taha
Published: December 2008

Some important olive cultivars (Kilis yağlık, Halhalı, Karamani, Haşebi, Nizip yağlık) in East Mediterranean Area were studied. Olive fruits were processed on a low‐scale mill equipped with a basket centrifuge. Basic quality parameters, the content of total polyphenols, o‐diphenols, oxidation stability (Rancimat) and antiradical activity [1,1‐diphenyl‐2‐picrylhydrazyl (DPPH)] were determined in oil samples. The highest induction period (IP) was 36.42 h, found in the Halhalı cultivar (from Gaziantep province), which also had strong radical scavenging activity (RSA) (96.72% in methanol:water extract and 94.91% in total oil) in all samples. The total phenol and o‐diphenol content for this cultivar were 495.42 and 76.89 mg caffeic acid/kg oil, respectively. The oxidation stability and antiradical activity of the Kilis yağlık cultivar (from Kilis province) was very poor when compared to other cultivar (IP; 10.40 h, RSA in methanol: water extract; 30.94%, RSA in total oil; 52.31%). In addition total phenol and o‐diphenol content for this cultivar were 38.31 and 5.03 mg caffeic acid/kg oil, respectively.
Infinite quasi-injective groups
Authors: Tomkinson M. J.
Published: December 2008

A group G is said to be quasi-injective if, for each subgroup H of G and homomorphism θ:H→G, there is an endomorphism such that . It is of course well known that the category of groups does not possess non-trivial injective objects and so we consider groups satisfying the weaker condition of quasi-injectivity.
Minimal generating systems of a subgroup of SL(2, ℂ)
Authors: Rosenberger Gerhard
Published: December 2008

Let H be any group. We call a cardinal number r the rank r(H) of H if H can be generated by a generating system X with cardinal number r but not by a generating system Y with cardinal number s less than r. Let r(H) be the rank of H.

We call a generating system X of H a minimal generating system (M.G.S.) of H if X has the cardinal number r(H).

In this note we prove the following.
Maximum-likelihood estimation of the parameters of a four-parameter class of probability distributions
Authors: Lehnigk Siegfried H.
Published: December 2008

We shall concern ourselves with the class of continuous, four-parameter, one-sided probability distributions which can be characterized by the probability density function (pdf) class

It depends on the four parameters: shift c ∈ R, scale b > 0, initial shape p < 1, and terminal shape β > 0. For p ≦ 0, the definition of f(x) can be completed by setting f(c) = β/bΓ(β−1)>0 if p = 0, and f(c) = 0 if p < 0. For 0 < p < 1, f(x) remains undefined at x = c; f(x)↑ + ∞ as x↓c.
Calculations of cylindricalp-homotopy groups
Authors: Ayala R. , Domínguez E. , Quintero A.
Published: December 2008

The definitions of the various proper homotopy groups correspond to three main geometrical ideas: sequences of spheres converging to a Freudenthal end (Brown groups); infinite cylinders giving the mobility of spheres towards a proper end (Čerin-Steenrod groups); sequences of spheres, each one movable to the next one following a proper end (Čech groups). The Brown and Čech groups have a rather complex structure and the calculations of these groups are very difficult (see [4]). The Čerin-Steenrod groups have a much simpler structure and this fact eases the computations.
The Borel structure of iterates of continuous functions
Authors: Humke Paul D. , Laczkovich M.
Published: December 2008

Let C[0,1] be the Banach space of continuous functions defined on [0,1] and let C be the set of functions f∈C[0,1] mapping [0,1] into itself. If f∈C, fk will denote the kth iterate of f and we put Ck = {fk:f∈C;}. The set of increasing (≡ nondecreasing) and decreasing (≡ nonincreasing) functions in C will be denoted by ℐ and D, respectively. If a function f is defined on an interval I, we let C(f) denote the set of points at which f is locally constant, i.e.

We let N denote the set of positive integers and NN denote the Baire space of sequences of positive integers.
Local structure of some Out(Fn)-complexes
Authors: Vogtmann Karen
Published: December 2008

In previous work of the author and M. Culler, contractible simplicial complexes were constructed on which the group of outer automorphisms of a free group of finite rank acts with finite stabilizers and finite quotient. In this paper, it is shown that these complexes are Cohen-Macauley, a property they share with buildings. In particular, the link of a vertex in these complexes is homotopy equivalent to a wedge of spheres of codimension 1.
Stability in pro-homotopy theory
Authors: Seymour R. M.
Published: December 2008

If is a category, an object of pro- is stable if it is isomorphic in pro- to an object of . A local condition on such a pro-object, called strong-movability, is defined, and it is shown in various contexts that this condition is equivalent to stability. Also considered, in the case is a suitable model category, is the stability problem in the homotopy category Ho(pro-), where pro- has the induced closed model category structure defined by Edwards and Hastings [6].
On the positive roots of an equation involving modified Bessel functions
Authors: Muldoon M. E.
Published: December 2008

We use the Mittag-Leffler partial fractions expansion of jv + 1(x)/Jv(x) to give simple proofs of some recent results due to S. H. Lehnigk concerning the number of positive roots of the equation ( −Br2 + A + q)Iq(r) + rIq,+ 1(r)=0, where A is real, B>0 and q>−1.