bluuebunny/crossref_metadata_2025 huggingface dataset:
Complicated Conversations
Authors: Hollingworth Liz
Published: February 2008

This is a case study of an elementary teacher's decision to add multicultural children's books to her curriculum and an analysis of how her ideologies about race shaped the classroom discourse. Although the teacher's stated purpose was to teach the pitfalls of racial stereotypes by encouraging conversations about prejudice, often the classroom talk normalized Whiteness in ways that shut down explorations of racial diversity, power, and oppression. This article describes how multicultural literature is used in an upper elementary classroom to supplement the existing curriculum and how a teacher's beliefs about race are present in the resulting discourse.
CEO Positive Psychological Traits, Transformational Leadership, and Firm Performance in High-Technology Start-up and Established Firms
Authors: Peterson Suzanne J. , Walumbwa Fred O. , Byron Kristin , Myrowitz Jason
Published: February 2008

This study examines the relationships among positive psychological traits (hope, optimism, resiliency), transformational leadership, and firm performance in high-technology start-up (n = 49) and established firm (n = 56) contexts, using structural equation modeling. Results reveal that the positive psychological traits of CEOs positively relate to transformational leadership ratings. Furthermore, the extent to which leaders are rated as transformational fully mediates the relationship between the leaders' positive psychological traits and their firms' performance. Last, transformational leadership is more strongly related to firm performance in start-up than in established firms. Implications for theory and practice are discussed.
Rater Reactions to Forced Distribution Rating Systems
Authors: Schleicher Deidra J. , Bull Rebecca A. , Green Stephen G.
Published: February 2008

Two experiments examined raters' reactions to a forced distribution rating system (FDRS), which, despite its popularity in organizations, has been largely ignored in the empirical research literature. Greater difficulty and less fairness were reported by raters when the FDRS was used for administrative purposes and when there was reduced variability in ratee performance. In addition, the FDRS was found to be more difficult and less fair than a more traditional rating scale format. Finally, difficulty and fairness reactions had significant implications for raters' confidence in their ability to provide feedback to the ratees and their self-efficacy for using the system going forward.
“Doing” Reflexive Modernization in Pig Husbandry
Authors: Bos Bram , Grin John
Published: February 2008

The Dutch animal production sector faces significant pressure for change. We discuss a project for the design of a sustainable husbandry system for pigs. Named after the Greek hero Hercules, the project aimed for structural changes in both animal and crop production. However, instead of changing the course of the river, the project ended up merely adapting its flow. The Hercules project ran into difficulties typical for projects aiming at reflexive modernization. It relapsed from an effort for reflexive modernization to ecological modernization, by ultimately leaving the structural features of the sociotechnical regime intact. We show how this resulted from the biases and limitations implied by existing institutions, in which the project was unavoidably embedded. We introduce the idea of reflexive design, as “doing” reflexive modernization, which implies working on action and structure at the same time. A number of recommendations are given for reflexive design projects like this.
An exploration of concepts of community through a case study of UK university web production
Authors: Cox Andrew M.
Published: February 2008

The paper explores the interrelation and differences between the concepts of occupational community, community of practice, online community and social network. It uses as a case study illustration the domain of UK university web site production and specifically a listserv for those involved in it. Different latent occupational communities are explored, and the potential for the listserv to help realize these as an active sense of community is considered. The listserv is not (for most participants) a tight knit community of practice, indeed it fails many criteria for an online community. It is perhaps best conceived as a loose knit network of practice, valued for information, implicit support and for the maintenance of weak ties. Through the analysis the case for using strict definitions of the theoretical concepts is made.
Exploring the emerging intellectual structure of archival studies using text mining: 2001—2004
Authors: Kim Heejung , Jae Yun Lee
Published: February 2008

Archival science, like other disciplines, is evolving into more specific interdisciplinary subfields. To determine this intellectual structure of archival science, the text mining method was used. The data were 432 articles from 2001 to 2004, and we produced 43 clusters of documents using the within-group average method in SPSS. Then we generated pathfinder networks of 43 clusters and grouped them into seven subject categories: digital libraries and digital archiving technologies, online resources and finding aids, archives and archivists, legal and political issues, electronic records and technical issues, records and information management, and e-mail and information professionals. Finally, these seven subject categories were merged into three sectors: digital library, archives and RIM (Business). This study describes dynamic change in the 2001—4 research themes from traditional single-subject areas to emerging, complex subject areas. These results also show that research areas in archival sciences have much growth potential and will continue to expand.
Islam and Democracy
Authors: Mishra Smeeta
Published: February 2008

Comparison of post-9/11 representations of Islam and democracy in the U.S. prestige press shows that despite differences in coverage in the Turkish, Iraqi, and Iranian contexts, fear of political Islam persisted in all three discursive environments. While a political role for Islam was regarded as a threat to democracy, the U.S. prestige press emphasized the need to secularize and modernize Islam according to Western standards to render it compatible with democracy. It highlighted human rights abuses in Iran and expressed concerns about the possibility of Iraq becoming another “Iran” if the power of religious parties went unchecked. Dominant discourses in the U.S. prestige press often assumed that any visibility of religious commitment in the public and political sphere automatically implied a lack of commitment to democracy, human rights, and women's rights. Discourses that contested dominant perspectives on Islam and democracy by questioning Western hegemonic definitions were limited.
Development and Validation of Videotaped Scenarios
Authors: Noel Nora E. , Maisto Stephen A. , Johnson James D. , Jackson Lee A. , Goings Christopher D. , Hagman Brett T.
Published: February 2008

Researchers using scenarios often neglect to validate perceived content and salience of embedded stimuli specifically with intended participants, even when such meaning is integral to the study. For example, sex and aggression stimuli are heavily influenced by culture, so participants may not perceive what researchers intended in sexual aggression scenarios. Using four studies, the authors describe the method of scenario validation to produce two videos assessing alcohol-related sexual aggression. Both videos are identical except for the presence in one video of antiforce cues that are extremely salient to the young heterosexual men. Focus groups and questionnaires validate these men's perceptions that (a) the woman was sexually interested, (b) the sexual cues were salient, (c) the antiforce cues were salient (antiaggression video only), and (e) these antiforce cues inhibited acceptance of forced sex. Results show the value of carefully selecting and validating content when assessing socially volatile variables and provide a useful template for developing culturally valid scenarios.
The Rosenzweig Picture-Frustration Study “Extra-Aggression” Score as an Indicator in Cognitive Restructuring Therapy for Male Perpetrators of Domestic Violence
Authors: Norman Michael , Ryan Lawrence J.
Published: February 2008

It was hypothesized that male perpetrators of domestic violence in the early stages of a 1-year process of cognitive restructuring therapy would manifest on the Rosenzweig Picture-Frustration Study higher levels of extra-aggressiveness than in later stages of the therapy process. A sample of male batterers in the process of treatment took the Rosenzweig instrument. The resulting responses were rated by trained scorers. Chi-square calculations reveled that batterers in the first quarter of treatment manifested Rosenzweig responses indicative of extra-aggressiveness, whereas in the fourth quarter, batterers manifested Rosenzweig responses indicative of im-aggression. The data are discussed relative to implications for domestic violence treatment and the use of the Rosenzweig instrument as an index of treatment progress.
A Safe Haven for Misbehaving?
Authors: Selwyn Neil
Published: February 2008

Although considerable academic interest has focused on serious cyber-crimes, more commonplace Internet misuses (e.g., misrepresentation of self, unauthorized downloading, Internet pornography, online plagiarism, and other “cyber-cheating”) have received less attention. Although these transgressions are of minor legal importance, they merit closer academic scrutiny. Based on a self-report study of 1,222 U.K. undergraduate students, this article explores the prevalence, nature, and underpinning facilitators of five examples of Internet-based misbehavior. Although more than 90% of respondents self-reported online misbehavior during the past 12 months, significant differences are evident in gender, Internet expertise, and, to a lesser extent, age. Although respondents portrayed the Internet as a more conducive environment for misbehavior, the survey data report a strong correlation between respondents' propensity to misbehave in online and offline contexts. These data highlight the need to contextualize cyber-deviance in relation to the offline “life world” of the Internet user and the Internet's wider role in everyday life.
Long-Term Administration of a Low-Molecular-Weight Heparin Contributed to Successful Treatment in a Patient With Primary Mediastinal Large B-Cell Lymphoma and Venous Thromboembolism
Authors: Mori Akio , Ibata Makoto , Mashiko Shinobu , Tsutsumi Yutaka , Masauzi Nobuo , Hashino Satoshi , Morioka Masanobu , Asaka Masahiro , Imamura Masahiro
Published: February 2008

The case of a 16-year-old girl with primary mediastinal large B-cell lymphoma who had thrombosis in the brachiocephalic, subclavian, and internal jugular veins at presentation is reported. MACOP-B chemotherapy plus radiation therapy could be the first-line strategy, but MACOP-B increases the risk of thrombosis. Although an effective method for initial treatment of venous thromboembolism (VTE) in cancer patients has not been established, recent studies revealed that the administration of a low-molecular-weight heparin (LMWH) was effective for secondary prevention of VTE. Therefore, the patient in this case was treated with MACOP-B plus rituximab followed by radiation therapy, and an LMWH was administered through the course of treatment. She achieved complete remission and never suffered from VTE. This case suggests that long-term administration of an LMWH contributes to the primary improvement and secondary prevention of VTE even in patients who are at high risk for thrombosis.
Is serum amyloid A an endogenous TLR4 agonist?
Authors: Sandri Silvana , Rodriguez Dunia , Gomes Eliane , Monteiro Hugo Pequeno , Russo Momtchilo , Campa Ana
Published: February 2008

Serum amyloid A (SAA), a classical acute-phase protein, is produced predominantly by hepatocytes in response to injury, infection, and inflammation. It has been shown that SAA primes leukocytes and induces the expression and release of proinflammatory cytokines. Here, we report that SAA induces NO production by murine peritoneal macrophages. Using specific inhibitors, we showed that NO production was dependent on inducible NO synthase thorough the activation of ERK1/2 and p38 MAPKs. Moreover, SAA activity was decreased after proteolysis but not with polymyxin B, a lipid A antagonist. Finally, we found that NO production was dependent on functional TLR4, a receptor complex associated with innate immunity. Macrophages from C3H/HeJ and C57BL/10ScCr mice lacking a functional TLR4 did not respond to SAA stimulation. In conclusion, our study makes a novel observation that SAA might be an endogenous agonist for the TLR4 complex on macrophages. The contribution of this finding in amplifying innate immunity during the inflammatory process is discussed.
LPS-induced up-regulation of TGF-β receptor 1 is associated with TNF-α expression in human monocyte-derived macrophages
Authors: Chen Yan , Kam Christy S K , Liu Feng Qin , Liu Yan , Lui Vincent C H , Lamb Jonathan R , Tam Paul K H
Published: February 2008

The immunosuppressive activity of TGF-β-mediated signaling is well documented, but in contrast, its ability to promote proinflammatory responses is less clear. In this study, we report that blockade of TGF-β signaling by a specific inhibitor of the TGF-β receptor I [activin receptor-like kinase 5 (ALK5)] SB431542 significantly reduces the production of TNF-α, a key proinflammatory cytokine, by LPS-stimulated human monocyte-derived macrophages. ALK5 protein was only detectable after LPS stimulation, and the failure of treatment with SB431542 to alter TNF-α mRNA expression indicates that regulation is post-transcriptional. The additive effect of blocking TGF-β and p38 MAPK signaling on reducing TNF-α but not IL-6 production suggests that there is selectivity in pathway signaling. SB431542 had similar inhibitory effects on TNF-α production by human monocytes and endothelial cells as well as macrophages. Furthermore, treatment with SB431542 reduced plasma TNF-α levels and tissue damage and thereby, prevented the lethal effects of LPS in a mouse model of septic shock. Our data demonstrate a direct effect of TGF-β signaling via ALK5 on the regulation of TNF-α synthesis.
Building γ-secretase – the bits and pieces
Authors: Spasic Dragana , Annaert Wim
Published: February 2008

γ-Secretase is a promiscuous aspartyl protease responsible for the final intramembrane cleavage of various type I transmembrane proteins after their large ectodomains are shed. The vast functional diversity of its substrates, which are involved in cell fate decisions, adhesion, neurite outgrowth and synapse formation, highlights the important role γ-secretase plays in development and neurogenesis. The most renowned substrates are the amyloid precursor protein and Notch, from which γ-secretase liberates amyloid β peptides and induces downstream signalling, respectively. γ-Secretase is a multiprotein complex containing presenilin (which harbours the catalytic site), nicastrin, APH1 and PEN2. Its assembly occurs under tight control of ER-Golgi recycling regulators, which allows defined quantities of complexes to reach post-Golgi compartments, where γ-secretase activity is regulated by multiple other factors. 3D-EM rendering reveals a complex with a translucent inner space, suggesting the presence of a water-filled cavity required for intramembrane proteolysis. Despite huge efforts, we are now only beginning to unravel the assembly, stoichiometry, activation and subcellular location of γ-secretase.
Kv3.3 Channels at the Purkinje Cell Soma Are Necessary for Generation of the Classical Complex Spike Waveform
Authors: Zagha Edward , Lang Eric J. , Rudy Bernardo
Published: February 2008

Voltage-gated potassium channel subunit Kv3.3 is prominently expressed in cerebellar Purkinje cells and is known to be important for cerebellar function, as human and mouse movement disorders result from mutations in Kv3.3. To understand these behavioral deficits, it is necessary to know the role of Kv3.3 channels on the physiological responses of Purkinje cells. We studied the function of Kv3.3 channels in regulating the synaptically evoked Purkinje cell complex spike, the massive postsynaptic response to the activation of climbing fiber afferents, believed to be fundamental to cerebellar physiology. Acute slice recordings revealed that Kv3.3 channels are required for generation of the repetitive spikelets of the complex spike. We found that spikelet expression is regulated by somatic, and not by dendritic, Kv3 activity, which is consistent with dual somatic–dendritic recordings that demonstrate spikelet generation at axosomatic membranes. Simulations of Purkinje cell Na+currents show that the unique electrical properties of Kv3 and resurgent Na+channels are coordinated to limit accumulation of Na+channel inactivation and enable rapid, repetitive firing. We additionally show that Kv3.3 knock-out mice produce altered complex spikesin vitroandin vivo, which is likely a cellular substrate of the cerebellar phenotypes observed in these mice. This characterization presents new tools to study complex spike function, cerebellar signaling, and Kv3.3-dependent human and mouse phenotypes.
Multidigit Movement Synergies of the Human Hand in an Unconstrained Haptic Exploration Task
Authors: Thakur Pramodsingh H. , Bastian Amy J. , Hsiao Steven S.
Published: February 2008

Although the human hand has a complex structure with many individual degrees of freedom, joint movements are correlated. Studies involving simple tasks (grasping) or skilled tasks (typing or finger spelling) have shown that a small number of combined joint motions (i.e., synergies) can account for most of the variance in observed hand postures. However, those paradigms evoked a limited set of hand postures and as such the reported correlation patterns of joint motions may be task-specific. Here, we used an unconstrained haptic exploration task to evoke a set of hand postures that is representative of most naturalistic postures during object manipulation. Principal component analysis on this set revealed that the first seven principal components capture >90% of the observed variance in hand postures. Further, we identified nine eigenvectors (or synergies) that are remarkably similar across multiple subjects and across manipulations of different sets of objects within a subject. We then determined that these synergies are used broadly by showing that they account for the changes in hand postures during other tasks. These include hand motions such as reach and grasp of objects that vary in width, curvature and angle, and skilled motions such as precision pinch. Our results demonstrate that the synergies reported here generalize across tasks, and suggest that they represent basic building blocks underlying natural human hand motions.
Developing Postmitotic Mammalian NeuronsIn VivoLacking Apaf-1 Undergo Programmed Cell Death by a Caspase-Independent, Nonapoptotic Pathway Involving Autophagy
Authors: Oppenheim Ronald W. , Blomgren Klas , Ethell Douglas W. , Koike Masato , Komatsu Masaaki , Prevette David , Roth Kevin A. , Uchiyama Yasuo , Vinsant Sharon , Zhu Changlian
Published: February 2008

Previous studies have shown that caspases and Apaf-1 are required for the normal programmed cell death (PCD)in vivoof immature postmitotic neurons and mitotically active neuronal precursor cells. In contrast, caspase activity is not necessary for the normal PCD of more mature postmitotic neurons that are establishing synaptic connections. Although normally these cells use caspases for PCD, in the absence of caspase activity these neurons undergo a distinct nonapoptotic type of degeneration. We examined the survival of these more mature postmitotic neuronal populations in mice in which Apaf-1 has been genetically deleted and find that they exhibit quantitatively normal PCD of developing postmitotic neurons. We next characterized the morphological mode of PCD in these mice and show that the neurons degenerate by a caspase-independent, nonapoptotic pathway that involves autophagy. However, autophagy does not appear to be involved in the normal PCD of postmitotic neurons in which caspases and Apaf-1 are present and functional because quantitatively normal neuronal PCD occurred in the absence of a key gene required for autophagy (ATG7). Finally, we examined the possible role of another caspase-independent type of neuronal PCD involving the apoptosis-inducing factor (AIF). Mice deficient in AIF also exhibit quantitatively normal PCD of postmitotic neurons after caspase inhibition. Together, these data indicate that, when key components of the type 1 apoptotic pathway (i.e., caspases and Apaf-1) are perturbedin vivo, developing postmitotic neurons nonetheless undergo quantitatively normal PCD by a caspase-independent pathway involving autophagy and not requiring AIF.
Cysteine-Rich Protein 2, a Novel Downstream Effector of cGMP/cGMP-Dependent Protein Kinase I-Mediated Persistent Inflammatory Pain
Authors: Schmidtko Achim , Gao Wei , Sausbier Matthias , Rauhmeier Inga , Sausbier Ulrike , Niederberger Ellen , Scholich Klaus , Huber Andrea , Neuhuber Winfried , Allescher Hans-Dieter , Hofmann Franz , Tegeder Irmgard , Ruth Peter , Geisslinger Gerd
Published: February 2008

The cGMP/cGMP-dependent protein kinase I (cGKI) signaling pathway plays an important role in spinal nociceptive processing. However, downstream targets of cGKI in this context have not been identified to date. Using a yeast two-hybrid screen, we isolated cysteine-rich protein 2 (CRP2) as a novel cGKI interactor in the spinal cord. CRP2 is expressed in laminas I and II of the mouse spinal cord and is colocalized with cGKI, calcitonin gene-related peptide, and isolectin B4. Moreover, the majority of CRP2 mRNA-positive dorsal root ganglion (DRG) neurons express cGKI and peripherin. CRP2 is phosphorylated in a cGMP-dependent manner, and its expression increases in the spinal cord and in DRGs after noxious stimulation of a hindpaw. To elucidate the functional role of CRP2 in nociception, we analyzed mice with a targeted deletion of CRP2. CRP2-deficient (CRP2−/−) mice demonstrate normal behavioral responses to acute nociception and after axonal injury of the sciatic nerve, but increased nociceptive behavior in models of inflammatory hyperalgesia compared with wild-type mice. Intrathecal administration of cGMP analogs increases the nociceptive behavior in wild-type but not in CRP2−/−mice, indicating that the presence of CRP2 is important for cGMP-mediated nociception. These data suggest that CRP2 is a new downstream effector of cGKI-mediated spinal nociceptive processing and point to an inhibitory role of CRP2 in the generation of inflammatory pain.
17β-Estradiol abrogates apoptosis in murine skeletal muscle cells through estrogen receptors: role of the phosphatidylinositol 3-kinase/Akt pathway
Authors: Vasconsuelo Andrea , Milanesi Lorena , Boland Ricardo
Published: February 2008

Estrogens can regulate apoptosis in various cellular systems. The present study shows that 17β-estradiol (E2), at physiological concentrations, abrogates DNA damage, poly (ADP-ribose) polymerase cleavage, and mitochondrial cytochrome c release induced by H2O2 or etoposide in mouse skeletal muscle C2C12 cells. This protective action, which involved PI3K/Akt activation and Bcl-2 associated death agonist (BAD) phosphorylation, was inhibited by antibodies against the estrogen receptor (ER) α or β isoforms, or transfecting siRNA specific for each isoform. The inhibition of the antiapoptotic action of E2 at the mitochondrial level was more pronounced when ER-β was immunoneutralized or suppressed by mRNA silencing, whereas transfection of C2C12 cells with either ER-α siRNA or ER-β siRNA blocked the activation of Akt by E2, suggesting differential involvement of ER isoforms depending on the step of the apoptotic/survival pathway evaluated. These results indicate that E2 exerts antiapoptotic effects in skeletal muscle cells which are mediated by ER-β and ER-α and involve the PI3K/Akt pathway.
Effects of ACTH, dexamethasone, and adrenalectomy on 11β-hydroxylase (CYP11B1) and aldosterone synthase (CYP11B2) gene expression in the rat central nervous system
Authors: Ye Ping , Kenyon Christopher J , MacKenzie Scott M , Nichol Katherine , Seckl Jonathan R , Fraser Robert , Connell John M C , Davies Eleanor
Published: February 2008

Using a highly sensitive quantitative RT-PCR method for the measurement of CYP11B1 (11β-hydroxylase) and CYP11B2 (aldosterone synthase) mRNAs, we previously demonstrated that CYP11B2 expression in the central nervous system (CNS) is subject to regulation by dietary sodium. We have now quantified the expression of these genes in the CNS of male Wistar Kyoto (WKY) rats in response to systemic ACTH infusion, dexamethasone infusion, and to adrenalectomy. CYP11B1 and CYP11B2 mRNA levels were measured in total RNA isolated from the adrenal gland and discrete brain regions using real-time quantitative RT-PCR. ACTH infusion (40 ng/day for 7 days, N=8) significantly increased CYP11B1 mRNA in the adrenal gland, hypothalamus, and cerebral cortex compared with animals infused with vehicle only. ACTH infusion decreased adrenal CYP11B2 expression but increased expression in all of the CNS regions except the cortex. Dexamethasone (10 μg/day for 7 days, N=8) reduced adrenal CYP11B1 mRNA compared with control animals but had no significant effect on either gene's expression in the CNS. Adrenalectomy (N=6 per group) significantly increased CYP11B1 expression in the hippocampus and hypothalamus and raised CYP11B2 expression in the cerebellum relative to sham-operated animals. This study confirms the transcription of CYP11B1 and CYP11B2 throughout the CNS and demonstrates that gene transcription is subject to differential regulation by ACTH and circulating corticosteroid levels.
Prostacyclin signaling regulates circulating ghrelin during acute inflammation
Authors: Madison Lisa D , Scarlett Jarrad M , Levasseur Peter , Zhu XinXia , Newcomb Kenneth , Batra Ayesha , Bowe Darren , Marks Daniel L
Published: February 2008

Ghrelin is an octanoylated 28 amino acid peptide predominantly secreted by the stomach, and has potent stimulatory effects on appetite. Several laboratories, including our own, have demonstrated that ghrelin levels fall in states of acute inflammation brought about by injection of bacterial lipopolysaccharide (LPS). We now demonstrate that the decrease in circulating ghrelin is not due to a decrease in ghrelin gene expression, but is instead likely to be due to an acute decrease in ghrelin secretion. Furthermore, we have found that the change in circulating ghrelin during acute inflammation required a prostaglandin second messenger, but did not require the synthesis of nitric oxide. Interestingly, i.v. injection of prostaglandin E2 failed to decrease circulating ghrelin levels, whereas prostacyclin decreased circulating ghrelin to a similar extent as did LPS. We also provide anatomical evidence for the mechanism of the regulation of ghrelin by inflammation. We demonstrate that the type 1 interleukin-1β (IL-1β) receptor is expressed within the gastric mucosa, but is not expressed by ghrelin cells. The prostacyclin receptor was also expressed in the gastric mucosa, and the majority of ghrelin-producing cells were found to co-express this receptor. Mice with genetic deletion of the type 1 IL-1 receptor do not suppress circulating ghrelin levels with LPS administration. Collectively, these data support a model in which the mechanism of inflammation induced decreases in ghrelin are due to the action of IL-1β on cells within the gastric mucosa that in turn produce prostacyclin as a second messenger. These data provide further support for the potential role of ghrelin as a therapeutic agent in acute and chronic inflammatory diseases.
Slow-light enhanced absorption for bio-chemical sensing applications: potential of low-contrast lossy materials
Authors: Pedersen Jesper , Xiao Sanshui , Mortensen Niels Asger
Published: February 2008

Slow-light enhanced absorption in liquid-infiltrated photonic crystals has recently been proposed as a route to compensate for the reduced optical path in typical lab-on-a-chip systems for bio-chemical sensing applications. A simple perturbative expression has been applied to ideal structures composed of lossless dielectrics. In this work we study the enhancement in structures composed of lossy dielectrics such as a polymer. For this particular sensing application we find that the material loss has an unexpected limited drawback and surprisingly, it may even add to increase the bandwidth for low-index contrast systems such as polymer devices.
Conducting ferromagnetic copolymer of aniline and 3,4‐ethylenedioxythiophene containing nanocrystalline barium ferrite particles
Authors: Ohlan Anil , Singh Kuldeep , Chandra A. , Dhawan S. K.
Published: February 2008

This article reports the synthesis of conducting ferromagnetic complex of 3,4‐ethylenedioxythiophene (EDOT) and aniline (An) containing M‐type hexagonal barium ferrite (BaFe12O19) particles using in situ emulsion polymerization and electrochemical oxidative polymerization. Magnetic and conductivity studies reveal that the conducting ferromagnetic complex possesses high‐saturation magnetization (Ms) value of 29.2 emu/g and conductivity of the order of 0.256 S/cm determined through vibrating sample magnetometer and four‐probe method. Microwave measurement has shown the reflection loss (RL) of −12.1 dB in Ku‐band that can be used as a microwave absorbing material. The polymer complex was further characterized by techniques like X‐ray diffraction, Fourier transform infrared, UV–visible, cyclic voltammetry, and thermal analysis with thermogravimetric analysis. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci 2008
Amphiphilic Cyclodextrins – Advances in Synthesis and Supramolecular Chemistry (Eur. J. Org. Chem. 6/2008)
Authors: Sallas Florence , Darcy Raphael
Published: February 2008

The cover picture shows a simulated micelle formed by amphiphilic cyclodextrin molecules above a landscape of real cyclodextrin vesicles. Synthesis of amphiphilic cyclodextrins, and the ranges of supramolecular assemblies formed by them, are presented in the Microreview by F. Sallas and R. Darcy on p. 957 ff.
Challenges for alexithymia research: a commentary on “The construct of alexithymia: associations with defense mechanisms”
Authors: Vanheule Stijn
Published: February 2008

The author comments on an article by Helmes and colleagues (this issue, pp. 000–000) that studied defense mechanisms related to alexithymia. What these authors observed is theoretically meaningful, and a distinct strength of this study is that the results are replicated in three independent samples. The study is also exemplary for two typical drawbacks— only student samples and self‐report measures are used. The author suggests that when studying alexithymia, researchers use samples that contain a substantial number of alexithymic subjects. Furthermore, variables such as emotional processing and regulation should not be measured with self‐report questionnaires alone. Emotional processing and regulation are, in part, implicit and researchers should consider this. The author argues that the standard of alexithymia research could be raised by including interdisciplinary perspectives and experimental methods, and by embedding research more explicitly in theories. © 2008 Wiley Periodicals, Inc. J Clin Psychol 64: 1–6, 2008.
Benchmarking urban six‐degree‐of‐freedom simultaneous localization and mapping
Authors: Wulf Oliver , Nüchter Andreas , Hertzberg Joachim , Wagner Bernardo
Published: February 2008

Quite a number of approaches for solving the simultaneous localization and mapping (SLAM) problem exist by now. Some of them have recently been extended to mapping environments with six‐degree‐of‐freedom poses, yielding 6D SLAM approaches. To demonstrate the capabilities of the respective algorithms, it is common practice to present generated maps and successful loop closings in large outdoor environments. Unfortunately, it is nontrivial to compare different 6D SLAM approaches objectively, because ground truth data about the outdoor environments used for demonstration are typically unavailable. We present a novel benchmarking method for generating the ground truth data based on reference maps. The method is then demonstrated by comparing the absolute performance of some previously existing 6D SLAM algorithms that build a large urban outdoor map. © 2008 Wiley Periodicals, Inc.
Change of surface property of dental impression materials according to time and disinfection
Authors: Kim Soo‐Hwa , Lee Doug‐Youn , Kim Kwang‐Mahn , Kim Kyoung‐Nam
Published: February 2008

The purpose of this study was to investigate the hydrophilicity of dental impression materials. Two ultrahydrophilic (Fusion, Genie) and four hydrophilic (Imprint II, Aquasilultra, Twinz, Perfect‐F) impression materials were used. Initially, 0.5% NaOCl and 1% povidone were used as disinfectants. In order to investigate the change of the surface wettability of impression materials according to the elapsed time after mixing, the contact angles were measured at 30 s and 2 min after mixing, respectively. Contact angles were also measured before and after disinfection. The contact angles of the ultrahydrophilic impression materials were lower at 2 min than at 30 s, whereas those of the hydrophilic impression materials showed the opposite result (p < 0.05). Fusion and Perfect‐F had higher contact angles in the NaOCl‐group and lower contact angles in the povidone‐group than those of nondisinfection group (p < 0.05). The contact angles of Aquasilultra and Twinz in the povidone‐group were higher than those in the nondisinfection group (p < 0.05). The elapsed time after mixing and disinfection of impression materials affected the contact angle of water on the surface of the impression materials. These results suggested that impression materials should only be used within the scope that their wettability is not degraded. Copyright © 2008 John Wiley & Sons, Ltd.
Transient megaoesophagus and oesophagitis following diaphragmatic rupture repair in a cat
Authors: Joseph Rotem , Kuzi Sharon , Lavy Eran , Aroch Itamar
Published: February 2008

A 6-month-old domestic shorthair female cat was presented with suspected diaphragmatic hernia (DH) that was later confirmed by thoracic radiography. The cat underwent exploratory celiotomy with a diaphragmatic rupture (DR) repair and recovered. Six days later, it was represented with vomiting and anorexia. Megaoesophagus (MO) and gastric dilatation were diagnosed by contrast radiography. A second celiotomy revealed no abnormalities and gastropexy was performed. Endoscopy demonstrated MO, oesophagitis and gastro-oesophageal reflux. MO persisted for several weeks and was an unexpected complication as no association between DR (or DH) and MO has never been described in the veterinary literature. The cat was treated medically with aggressive prokinetic and antacid therapy along with prolonged temporary oesophageal diversion (percutaneous endoscopic gastrostomy tube) with an excellent outcome.
Correlations between ion conics and electron beams observed by the Viking satellite in the cusp‐cleft region
Authors: Thelin B. , Lundin R. , Aparicio B.
Published: February 2008

Measurements of upward electron beams and ion conics from the polar orbiting Viking satellite have been obtained in the cusp‐cleft region. The relative frequencies of occurrence have been calculated for studies of the MLT, Inv. Lat, and altitude distribution during the period March to June 1986. It was observed that the upward electron beams were more frequent in the dawn sector compared to the dusk sector. Similar observations have also been seen for ion conics.

The Invariant Latitude dependence of upflowing electron beams shows a clear maximum around 78°. This agrees well with the maximum for ion conics.

The altitude dependence shows a steep increase in frequency above 10,000 km up to the satellite apogee (≈ 13 500 km). This altitude dependence at different AE index was also studied giving information about the acceleration region and the altitude profiles at different levels of magnetic disturbance.
Laboratory simulation, A tool for comet research
Authors: Grün E. , Kochan H. , Seidensticker K. J.
Published: February 2008

Simulation experiments are performed in order to study processes which could lead to a better understanding of cometary nuclei. During the KOSI (Kometensimulation) experiments decimeter‐sized samples of porous H2O and CO2 ice‐dust mixtures are irradiated with light. Phenomena like heat transport into the sample, compositional and structural modifications of the sample and release of dust and gas are studied which occur within centimeter to decimeter distance from the sample surface. Techniques to handle and analyse low temperature ice samples are developed. So far, six KOSI experiments have been performed and about six more are expected to be carried out within the next three years. This paper describes the approach taken and techniques used in the KOSI experiments. We discuss the relevance of some initial results obtained for cometary research.
Interpretation of the electric fields measured in an ionospheric critical ionization velocity experiment
Authors: Brenning N. , Fälthammar C.‐G. , Haerendel G. , Kelley M. C. , Marklund G. , Pfaff R. , Providakes J. , Stenbaek‐Nielsen H. C. , Swenson C. , Torbert R. , Wescott E. M.
Published: February 2008

This paper deals with the quasi‐dc electric fields measured in the CRIT I ionospheric release experiment, which was launched from Wallops Island on May 13, 1986. The purpose of the experiment was to study the critical ionization velocity (CIV⋕ mechanism in the ionosphere. Two identical barium shaped charges were fired from distances of 1.99 km and 4.34 km towards a main payload, which made full three‐dimensional measurements of the electric field inside the streams. There was also a subpayload separated from the main payload by a couple of kilometers along the magnetic field. The relevance of earlier proposed mechanisms for electron heating in CIV is investigated in the light of the CRIT I results. It is concluded that both the “homogeneous” and the “ionizing front” models probably apply, but in different parts of the stream. It is also possible that electrons are directly accelerated by a magnetic‐field‐aligned component of the electric field; the quasi‐dc electric field observed within the streams had a large magnetic‐field‐aligned component, persisting on the time scale of the passage of the streams. The coupling between the ambient ionosphere and the ionized barium stream in CRIT I was more complicated than is usually assumed in CIV theories, with strong magnetic‐field‐aligned electric fields and probably current limitation as important processes. One interpretation of the quasi‐dc electric field data is that the internal electric fields of the streams were not greatly modified by magnetic‐field‐aligned currents, i.e., a state was established where the transverse currents were to a first approximation divergence‐free. It is argued that this interpretation can explain both a reversal of the strong explosion‐directed electric field in burst 1 and the absence of such a reversal in burst 2.
Electron acceleration at nearly perpendicular collisionless shocks: 2. Reflection at curved shocks
Authors: Krauss‐Varban D. , Burgess D.
Published: February 2008

Electrons can be efficiently energized at interplanetary shocks and planetary bow shocks. The acceleration and reflection process is extremely sensitive to the angle θBn between the upstream magnetic field and the shock normal, and is most prominent at θBn ∼ 90°. The mechanism has been investigated by theoretical and simulation means, and can be interpreted as a fast Fermi process or as gradient drift acceleration. Previous work has been carried out for plane shocks only, and is expanded here to take into account the global curvature of a shock. Simple estimates suggest that this curvature may have a strong limiting effect on the acceleration to high energies, i.e., above several keV in case of the Earth's bow shock. We perform two‐dimensional test particle calculations to address this question, and evaluate the reflected electron flux as a function of θBn at the shock surface. The shock profile is derived from hybrid code simulations, and modified to include the first order effects of a global curvature in the vicinity of θBn = 90°. At low energies, the calculated fluxes exhibit a cut‐off and a maximum, which can give rise to observed bump‐on‐tail distributions in the electron foreshock. Results at high energy show that while individual electrons gain less energy in a curved shock, concerning the flux this fact is largely offset by two‐dimensional focusing effects. Electrons that drift into the shock over a wide area converge and stream out within a narrow spatial area, thus greatly enhancing the flux of reflected electrons. A κ distribution of suprathermal solar wind electrons (of index κ = 6) is capable of producing the observed large fluxes of reflected electrons at the Earth's bow shock up to energies of 10 to 15 keV, even when the global shock curvature is accounted for. Beyond this energy range observed spectra are harder, as has been found previously for a plane shock. As a likely reason, the solar wind seed population may be denser than modeled above several keV.
Feedback instability of the ionospheric resonant cavity
Authors: Lysak Robert L.
Published: February 2008

The exponential increase of the Alfvén speed in the topside ionosphere leads to the formation of a resonant cavity (Lysak, 1988) which has been termed the ionospheric Alfvén resonator by Trakhtengertz and Feldstein (1984). These authors primarily considered the situation where the ionospheric Pedersen conductivity is low, while Lysak (1988) considered the opposite limit of infinite ionospheric conductivity. These results have been extended to arbitrary ionospheric conductivity by performing a numerical solution of the cavity dispersion relation, which involves Bessel functions of complex argument and order. These results indicate that the damping of excitations of this resonant cavity is strongest when the ionospheric Pedersen and Alfvén conductivities are comparable and that growth is possible for incoming wave boundary conditions. The existence of this cavity leads to a modification of the Alfvén wave reflection coefficient at the ionosphere. While this reflection coefficient is independent of frequency at low frequencies, it exhibits structure due to the resonant cavity modes at frequencies around 0.1–1 Hz. These cavity modes can also be excited by feedback instabilities (Sato, 1978; Lysak, 1986), leading to growth rates which are enhanced over the case without the cavity. These waves have maximum growth at short wavelengths, particularly when the background Pedersen conductivity is large. The perturbations associated with these instabilities can lead to structuring of auroral currents during substorms, and may help explain the westward traveling surge.
Laboratory simulations of suprauroral mechanisms leading to perpendicular ion heating and conic formation
Authors: Sheehan D. P. , Koslover R. , McWilliams R.
Published: February 2008

Laboratory experiments are presented simulating aspects of perpendicular ion heating and conic formation that are observed or hypothesized to occur in the terrestrial ionosphere and magnetosphere. Previous laboratory observations of ion conics in the presence of the current‐driven electrostatic ion cyclotron wave are reviewed. Field‐aligned ion beams, accompanied by beam‐generated electrostatic ion cyclotron modes, resulted in perpendicular energization of beam ions and also the heating of background plasma ions. Antenna‐launched broadband and narrow‐band lower hybrid waves produced considerable perpendicular ion heating and non‐Maxwellian “tail” formation. Laboratory results are discussed in light of in situ measurements by the S3‐3 satellite and the MARIE sounding rocket.
The source surface and photospheric magnetic field models
Authors: Saito T. , Kozuka Y. , Ôki T. , Akasofu S.‐I.
Published: February 2008

It is possible to reproduce the configuration of the neutral line on the solar source surface by the axial dipole at the center of the Sun and a few fictitious dipoles on the photosphere. In this paper we attempt to identify the nature of such fictitious dipoles in the photospheric magnetic fields. It is shown that large‐scale photospheric dipole fields can be identified clearly at the locations indicated by the fictitious dipoles when the photospheric field is very simple. They are found to be active regions.
Effects of atmospheric modeling errors on determinations of baseline vectors from very long baseline interferometry
Authors: Davis J. L. , Herring T. A. , Shapiro I. I.
Published: February 2008

We have performed a series of special very long baseline interferometry (VLBI) experiments that involve a significant fraction of group delay measurements made at very low elevation angles. Twenty‐two such low‐elevation experiments, each ∼26 hours in duration, were performed over a period of ∼2.5 years using VLBI antennas at the Goldstone complex in California and at Westford, Massachusetts. The purpose of these experiments was to expose and study errors in the formula for the elevation angle dependence of the atmospheric propagation delay, called the “mapping function.” Errors in this formula are a principal source of error in estimates of vertical coordinate of site position and make a significant contribution to the error in estimates of baseline length for transcontinental and longer baselines. For the low‐elevation experiments, estimates of baseline length had a root‐mean‐square (RMS) residual about the mean value of 7 mm, or about 1.7 parts per billion for this 3900‐km baseline. This scatter is about 20% greater than that calculated by propagating the random measurement noise through a Kaiman filter, which includes the noise contributions of the atmospheres and hydrogen maser “clocks” as well. We used specialized statistical tests to determine the contribution of mapping function errors to the estimates of vertical coordinate of site position and found this contribution to be less than 19 mm RMS. This value is roughly consistent with the observed larger‐than‐predicted scatter of the estimates of baseline length. We further found that for the 1–2 month spacing of our experiments, the mapping function errors do not exhibit a coherent annual signature but appear to be random in the long term.
A mobile four‐electrode array and its application to the electrical survey of planetary grounds at shallow depths
Authors: Grard R. , Tabbagh A.
Published: February 2008

This paper deals with a mobile array for mapping the electric properties of planetary surfaces, with a resolution of the order of a few meters in all dimensions. The principle of the measuring technique is first recapitulated; the prototype model of this novel instrument is then described. The array was operated at a frequency of 128 kHz over a site with apparent resistivities in the range 20–100 Ω m and the experimental results are found to be in excellent agreement with those derived from another independent technique. It is demonstrated, from measurements collected on a second site with resistivities of the order of several kilo‐ohm meters, that this new technique also yields information about the dielectric constant of the ground. This method is not only applicable to geological surveys on Earth but also appears particularly attractive for the exploration of the surface of other planets by means of landers, penetrators, or unmanned rovers.