bluuebunny/crossref_metadata_2025 huggingface dataset:
Mechanisms of tissue fusion during development
Authors: Ray Heather J. , Niswander Lee
Published: April 2012

Tissue fusion events during embryonic development are crucial for the correct formation and function of many organs and tissues, including the heart, neural tube, eyes, face and body wall. During tissue fusion, two opposing tissue components approach one another and integrate to form a continuous tissue; disruption of this process leads to a variety of human birth defects. Genetic studies, together with recent advances in the ability to culture developing tissues, have greatly enriched our knowledge of the mechanisms involved in tissue fusion. This review aims to bring together what is currently known about tissue fusion in several developing mammalian organs and highlights some of the questions that remain to be addressed.
Functional interactions between Fat family cadherins in tissue morphogenesis and planar polarity
Authors: Saburi Sakura , Hester Ian , Goodrich Lisa , McNeill Helen
Published: April 2012

The atypical cadherin fat (ft) was originally discovered as a tumor suppressor in Drosophila and later shown to regulate a form of tissue patterning known as planar polarity. In mammals, four ft homologs have been identified (Fat1-4). Recently, we demonstrated that Fat4 plays a role in vertebrate planar polarity. Fat4 has the highest homology to ft, whereas other Fat family members are homologous to the second ft-like gene, ft2. Genetic studies in flies and mice imply significant functional differences between the two groups of Fat cadherins. Here, we demonstrate that Fat family proteins act both synergistically and antagonistically to influence multiple aspects of tissue morphogenesis. We find that Fat1 and Fat4 cooperate during mouse development to control renal tubular elongation, cochlear extension, cranial neural tube formation and patterning of outer hair cells in the cochlea. Similarly, Fat3 and Fat4 synergize to drive vertebral arch fusion at the dorsal midline during caudal vertebra morphogenesis. We provide evidence that these effects depend on conserved interactions with planar polarity signaling components. In flies, the transcriptional co-repressor Atrophin (Atro) physically interacts with Ft and acts as a component of Fat signaling for planar polarity. We find that the mammalian orthologs of atro, Atn1 and Atn2l, modulate Fat4 activity during vertebral arch fusion and renal tubular elongation, respectively. Moreover, Fat4 morphogenetic defects are enhanced by mutations in Vangl2, a ‘core’ planar cell polarity gene. These studies highlight the wide range and complexity of Fat activities and suggest that a Fat-Atrophin interaction is a conserved element of planar polarity signaling.
Hormonal activation of let-7-C microRNAs via EcR is required for adult Drosophila melanogaster morphology and function
Authors: Chawla Geetanjali , Sokol Nicholas S.
Published: April 2012

Steroid hormones and their nuclear receptors drive developmental transitions in diverse organisms, including mammals. In this study, we show that the Drosophila steroid hormone 20-hydroxyecdysone (20E) and its nuclear receptor directly activate transcription of the evolutionarily conserved let-7-complex (let-7-C) locus, which encodes the co-transcribed microRNAs miR-100, let-7 and miR-125. These small RNAs post-transcriptionally regulate the expression of target genes, and are required for the remodeling of the Drosophila neuromusculature during the larval-to-adult transition. Deletion of three 20E responsive elements located in the let-7-C locus results in reduced levels of let-7-C microRNAs, leading to neuromuscular and behavioral defects in adults. Given the evolutionary conservation of let-7-C microRNA sequences and temporal expression profiles, these findings indicate that steroid hormone-coupled control of let-7-C microRNAs is part of an ancestral pathway controlling the transition from larval-to-reproductive animal forms.
Credit Booms Gone Bust: Monetary Policy, Leverage Cycles, and Financial Crises, 1870–2008
Authors: Schularick Moritz , Taylor Alan M
Published: April 2012

The financial crisis has refocused attention on money and credit fluctuations, financial crises, and policy responses. We study the behavior of money, credit, and macroeconomic indicators over the long run based on a new historical dataset for 14 countries over the years 1870–2008. Total credit has increased strongly relative to output and money in the second half of the twentieth century. Monetary policy responses to financial crises have also been more aggressive, but the output costs of crises have remained large. Credit growth is a powerful predictor of financial crises, suggesting that policymakers ignore credit at their peril. JEL: E32, E44, E52, G01, N10, N20
What Drives US Foreign Borrowing? Evidence on the External Adjustment to Transitory and Permanent Shocks
Authors: Corsetti Giancarlo , Konstantinou Panagiotis Th
Published: April 2012

The joint dynamics of US net output, consumption, and (the market value of) foreign assets and liabilities, characterized empirically following Lettau and Ludvigson (2004), is shown to be consistent with current account theory. US consumption is virtually insulated from transitory shocks, while these contribute to variations in net output and gross foreign positions—consumption is smoothed against temporary fluctuations in returns. A single permanent shock—naturally interpreted as a supply shock—raises consumption swiftly while causing net output to adjust gradually. This leads to persistent, procyclical external deficits, while moving gross assets and liabilities in the same direction. JEL: E21, E23, F32, F34
International Income Inequality: Measuring PPP Bias by Estimating Engel Curves for Food
Authors: Almås Ingvild
Published: April 2012

Purchasing power–adjusted incomes applied in cross-country comparisons are measured with bias. This paper estimates the purchasing power parity (PPP) bias in Penn World Table incomes and provides corrected incomes. The bias is substantial and systematic: the poorer a country, the more its income tends to be overestimated. Consequently, international income inequality is substantially underestimated. The methodological contribution is to exploit the analogies between PPP bias and the bias in consumer price index (CPI) numbers. The PPP bias and subsequent corrected incomes are measured by estimating Engel curves for food, an established method of measuring CPI bias. JEL: C43, D31, E31, O11, O12
Competition through Commissions and Kickbacks
Authors: Inderst Roman , Ottaviani Marco
Published: April 2012

In markets for retail financial products and health services, consumers often rely on the advice of intermediaries to decide which specialized offering best fits their needs. Product providers, in turn, compete to influence the intermediaries' advice through hidden kickbacks or disclosed commissions. Motivated by the controversial role of these widespread practices, we formulate a model to analyze competition through commissions from a positive and normative standpoint. The model highlights the role of commissions in making the advisor responsive to supply-side incentives. We characterize situations when commonly adopted policies such as mandatory disclosure and caps on commissions have unintended welfare consequences. (JEL D21, D82, D83, G21, L15, L25)
Screening, Competition, and Job Design: Economic Origins of Good Jobs
Authors: Bartling Björn , Fehr Ernst , Schmidt Klaus M
Published: April 2012

High-performance work systems give workers more discretion, thereby increasing effort productivity but also shirking opportunities. We show experimentally that screening for work attitude and labor market competition are causal determinants of the viability of high-performance work systems, and we identify the complementarities between discretion, rent-sharing, and screening that render them profitable. Two fundamentally distinct job designs emerge endogenously in our experiments: “bad” jobs with low discretion, low wages, and little rent-sharing, and “good” jobs with high discretion, high wages, and substantial rent-sharing. Good jobs are profitable only if employees can be screened, and labor market competition fosters their dissemination. (JEL D12, D82, J24, J31, J41, M12, M54)
Thar She Bursts: Reducing Confusion Reduces Bubbles
Authors: Kirchler Michael , Huber Jürgen , Stöckl Thomas
Published: April 2012

To explore why bubbles frequently emerge in the experimental asset market model of Smith, Suchanek, and Williams (1988), we vary the fundamental value process (constant or declining) and the cash– to–asset value ratio (constant or increasing). We observe high mispricing in treatments with a declining fundamental value, while overvaluation emerges when coupled with an increasing C/A ratio. A questionnaire reveals that the declining fundamental value process confuses subjects, as they expect the fundamental value to stay constant. Running the experiment with a different context (“stocks of a depletable gold mine” instead of “stocks”) significantly reduces mispricing and overvaluation as it reduces confusion. (JEL C91, D14, G11, G12)
Information and Industry Dynamics
Authors: Dinlersoz Emin M , Yorukoglu Mehmet
Published: April 2012

This paper develops a model of industry dynamics where firms compete to acquire customers over time by disseminating information about themselves in the presence of random shocks to their efficiency. The properties of the model's stationary equilibrium are related to empirical regularities on firm and industry dynamics. As an application of the model, the effects of a decline in the cost of information dissemination on firm and industry dynamics are explored. (JEL D11, D83, L11, L81, M37)
Carrot or Stick? The Evolution of Reciprocal Preferences in a Haystack Model
Authors: Herold Florian
Published: April 2012

We study the evolution of both characteristics of reciprocity: the willingness to reward and the willingness to punish. First, both preferences for rewarding and preferences for punishing can survive provided that individuals interact within separate groups. Second, rewarders survive only in coexistence with self-interested preferences, but punishers either vanish or dominate the population entirely. Third, the evolution of preferences for rewarding and the evolution of preferences for punishing influence each other decisively. Rewarders can invade a population of self-interested players. The existence of rewarders enhances the evolutionary success of punishers, who then crowd out all other preferences. (JEL C71, C72, C73, D64, K42)
Radiation dose reduction in CT of the brain: can advanced noise filtering compensate for loss of image quality?
Authors: Siemund Roger , Löve A , van Westen D , Stenberg L , Petersen C , Björkman-Burtscher IM
Published: April 2012

Background

Computed tomography (CT) of the brain is performed with high local doses due to high demands on low contrast resolution. Advanced algorithms for noise reduction might be able to preserve critical image information when reducing radiation dose.

Purpose

To evaluate the effect of advanced noise filtering on image quality in brain CT acquired with reduced radiation dose.

Material and Methods

Thirty patients referred for non-enhanced CT of the brain were examined with two helical protocols: normal dose (ND, CTDIvol 57 mGy) and low dose (LD, CTDIvol 40 mGy) implying a 30% radiation dose reduction. Images from the LD examinations were also postprocessed with a noise reduction software with non-linear filters (SharpView CT), creating filtered low dose images (FLD) for each patient. The three image stacks for each patient were presented side by side in randomized order. Five radiologists, blinded for dose level and filtering, ranked these three axial image stacks (ND, LD, FLD) as best to poorest (1 to 3) regarding three image quality criteria. Measurements of mean Hounsfield units (HU) and standard deviation (SD) of the HU were calculated for large region of interest in the centrum semiovale as a measure for noise.

Results

Ranking results in pooled data showed that the advanced noise filtering significantly improved the image quality in FLD as compared to LD images for all tested criteria. No significant differences in image quality were found between ND examinations and FLD. However, there was a notable inter-reader spread of the ranking. SD values were 15% higher for LD as compared to ND and FLD.

Conclusion

The advanced noise filtering clearly improves image quality of CT examinations of the brain. This effect can be used to significantly lower radiation dose.
The effect of frequency and phonological neighbourhood density on the acquisition of past tense verbs by Finnish children
Authors: Kirjavainen, Minna , Nikolaev, Alexandre , Kidd, Evan
Published: April 2012

The acquisition of the past tense has received substantial attention in the psycholinguistics literature, yet most studies report data from English or closely related Indo-European languages. We report on a past tense elicitation study on 136 4–6-year-old children that were acquiring a highly inflected Finno-Ugric (Uralic) language—Finnish. The children were tested on real and novel verbs (N = 120) exhibiting (1) productive, (2) semi-productive, or (3) non-productive inflectional processes manipulated for frequency and phonological neighbourhood density (PND). We found that Finnish children are sensitive to lemma/base frequency and PND when processing inflected words, suggesting that even though children were using suffixation processes, they were also paying attention to the item level properties of the past tense verbs. This paper contributes to the growing body of research suggesting a single analogical/associative mechanism is sufficient in processing both productive (i.e., regular-like) and non-productive (i.e., irregular-like) words. We argue that seemingly rule-like elements in inflectional morphology are an emergent property of the lexicon.
Mechanisms of resistance to endocrine therapies for breast cancer
Authors: Heudel Pierre , Vilquin Paul , Tredan Olivier , Ray-Coquard Isabelle , Guastalla Jean-Paul , Treilleux Isabelle , Bachelot Thomas
Published: April 2012

Breast cancer is the most frequently diagnosed cancer in women and 70% of the cases are hormone-dependent. The presence of ERα is one of the most important prognostic factors predictive of response to endocrine therapy in human breast cancers. Resistance to endocrine therapies has become a major public health concern and it appears essential to understand the mechanisms underlying this phenomenon. This review provides insights into the molecular mechanisms associated with resistance to endocrine therapies and presents the different strategies currently developed in pre-clinical models to overcome this resistance.
Molecular mechanisms of oestrogen action on growth of human breast cancer cells in culture
Authors: Darbre Philippa D.
Published: April 2012

Growth responses to oestrogen can be reproducibly obtained using a selection of oestrogen-receptor-containing human breast cancer cell lines, and molecular mechanisms have been shown to include modulation to growth factor/receptor/signalling pathways, cell-cycle proteins, apoptosis, differentiation, adhesion, motility and migration. Considerable progress has been made in understanding the molecular basis of oestrogen action on gene expression through the ligand-activated transcription factors human oestrogen receptor α (ERα) and ERβ and the resulting effects on global gene expression patterns, but the full profile of coordination of the alterations, which brings about changes in cell growth through genomic and non-genomic mechanisms remain to be fully elucidated. Oestrogen regulation of cell growth involves a complex cross-talk between oestrogen receptor and growth factor signalling pathways such that inhibition of one pathway may lead to stimulation of another, which may explain the remarkable ability of human breast cancer cells to escape from any mode of imposed growth inhibition be it oestrogen deprivation or administration of antioestrogen. Although studies on cell growth have focused to date on the effects of physiological oestrogens, many hundreds of environmental chemicals with oestrogenic properties have now been measured in the human breast. Whether or not the weight of evidence eventually establishes any causal link of complex mixtures of environmental oestrogenic chemicals with breast cancer, the presence of so many oestrogenic chemicals in the breast must influence resulting oestrogenic responses, and the impact of this additional oestrogenic burden needs to be taken into account in future studies on growth regulation of human breast cancer cells.
Models and mechanisms of acquired antihormone resistance in breast cancer: significant clinical progress despite limitations
Authors: Sweeney Elizabeth E. , McDaniel Russell E. , Maximov Philipp Y. , Fan Ping , Jordan V. Craig
Published: April 2012

Translational research for the treatment and prevention of breast cancer depends upon the four Ms: models, molecules, and mechanisms in order to create medicines. The process, to target the estrogen receptor (ER) in estrogen-dependent breast cancer, has yielded significant advances in patient survivorship and the first approved medicines (tamoxifen and raloxifene) to reduce the incidence of any cancer in high- or low-risk women. This review focuses on the critical role of the few ER-positive cell lines (MCF-7, T47D, BT474, ZR-75-1) that continue to advance our understanding of the estrogen-regulated biology of breast cancer. More importantly, the model cell lines have provided an opportunity to document the development and evolution of acquired antihormone resistance. The description of this evolutionary process that occurs in micrometastatic disease during up to a decade of adjuvant therapy would not be possible in the patient. The use of the MCF-7 breast cancer cell line, in particular, has been instrumental in discovering a vulnerability of ER-positive breast cancer exhaustively treated with antihormone therapy. Physiologic estradiol acts as an apoptotic trigger to cause tumor regression. These unanticipated findings in the laboratory have translated to clinical advances in our knowledge of the paradoxical role of estrogen in the life and death of breast cancer.
Molecular basis of pregnancy-induced breast cancer prevention
Authors: Russo Jose , Russo Irma H.
Published: April 2012

Reduction in breast cancer risk is associated with elevated circulating levels of human chorionic gonadotropin (hCG) during the first trimester of gestation. The knowledge that hCG also modifies the genomic signature of breast epithelial cells, from highly susceptible to refractory, to undergo neoplastic transformation, and also exerts both preventive and therapeutic effects on chemically induced mammary cancer, lead us to select this hormone for inducing chromatin remodeling in breast epithelial cells as a surrogate end point of complete differentiation and cancer prevention. We have found that chromatin remodeling is the driving force of the differences between the nulliparous and parous breast. In the parous breast, the epithelial cells have a condensed chromatin and increased reactivity with anti-H3K9me2 [di-methyl histone 3 (H3) (Lysine 9)] and H3K27me3 antibodies. This is accompanied by upregulation of noncoding RNA (ncRNA) elements including X2-inactive specific transcript (XIST) and chromatin remodeling genes, such as chromodomain helicase DNA-binding protein 2 (CHD2) and the chromobox homolog 3 (CBX3), whose products are required for controlling recruitment of protein/protein or DNA/protein interactions Another important gene upregulated in the parous breast epithelial cells is the histone-lysine N-methyltransferase or enhancer of zeste homolog 2 (EZH2), a member of the polycomb group (PcG) forming multimeric protein complexes that maintains the transcriptional repressive state of genes over successive cell generations. The fact that recent studies indicate that ncRNAs recruit PcG complexes to the locus of transcription or to sites located elsewhere in the genome cause us to postulate that the increased chromatin condensation in the parous breast has been initiated by ncRNAs, a postulate supported by the observed upregulation of several ncRNAs that included the XIST. The identification of a specific genomic signature of pregnancy has uncovered a novel tool that will serve as a surrogate biomarker for testing new chemopreventive agents and will significantly advance the field of cancer prevention. The clinical impact of this work is that it validates in an experimental system the genomic signature of prevention identified in the human parous breast and establish the bases for the use of the hormone hCG in the prevention of breast cancer, an approach that has not been fully developed until now.
Cytochrome P450-7B1 and 11β-hydroxysteroid dehydrogenase type 1 distribution in human tissues
Authors: Chalbot Sonia , Morfin Robert
Published: April 2012

Successive action of cytochrome P450-7B1 (CYP7B1) and 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1) on 3β-hydroxysteroids such as DHEA and epiandrosterone leads to the production of cytoprotective 7β-hydroxylated derivatives. Investigation of the presence of these enzymes in human tissues could be carried out on commercially available human tissue arrays with use of antibodies specific to CYP7B1 and 11β-HSD1 for immunohistochemistry. Both enzymes were detected mainly in tissues of endodermic and ectodermic origin which are prone to undergo inflammation. As low doses of the 7β-hydroxylated derivatives of DHEA and epiandrosterone trigger the resolution of inflammation and tissue repair, CYP7B1 and 11β-HSD1 tissue contents may reflect the tissue ability for reparation after pathological conditions.
Estetrol prevents and suppresses mammary tumors induced by DMBA in a rat model
Authors: Visser Monique , Kloosterboer Helenius J. , Bennink Herjan J.T. Coelingh
Published: April 2012

Background: Estetrol (E4) is a pregnancy-specific estrogenic steroid hormone produced by the human fetal liver in both male and female fetuses. During pregnancy, E4 plasma values increase exponentially until parturition and decrease thereafter. The synthesis of E4 in the liver of a newborn ceases during the first weeks after birth.

Materials and methods: Here we report the effect of E4 on the initiation and growth of mammary tumors chemically induced by 7,12 dimethylbenz(a)anthracene (DMBA) in female Sprague-Dawley rats in two different protocols. Two prevention studies to test the effect on initiation and growth of induced tumors and one intervention study to test the effect on tumor growth were performed. In the prevention studies, the effect of oral doses of E4 over a dose range of 0.5–3.0 mg/kg was investigated. In the intervention study, oral doses of 1, 3 and 10 mg/kg E4 were used. The anti-estrogen tamoxifen (TAM) and ethinylestradiol (EE) were used as reference compounds. In all studies, a group with ovariectomized animals (OVX) was included.

Results: In the prevention studies, 2.5 mg and 3 mg/kg E4 showed a significant effect on the number and growth of induced tumors by DMBA, and the effects were comparable to those of TAM, whereas EE had no effect. In the intervention study, the effect of a high dose of E4 (10 mg/kg) on tumor number was similar to that of OVX and better than TAM and high-dose EE. The 3 mg/kg E4 had an effect comparable to high-dose EE. The treatment effects were largely due to complete regression of existing tumors.

Conclusions: The natural fetal estrogen E4 prevents tumor initiation by DMBA and inhibits the growth of existing DMBA-induced tumors.
Hormonal enzymatic systems in normal and cancerous human breast: control, prognostic factors, and clinical applications
Authors: Pasqualini Jorge R. , Chetrite Gérard S.
Published: April 2012

The bioformation and transformation of estrogens and other hormones in the breast tissue as a result of the activity of the various enzymes involved attract particular attention for the role they play in the development and pathogenesis of hormone-dependent breast cancer. The enzymatic process concerns the aromatase, which transforms androgens into estrogens; the sulfatase, which hydrolyzes the biologically inactive sulfates to the active hormone; the 17β-hydroxysteroid dehydrogenases, which are involved in the interconversion estradiol/estrone or testosterone/androstenedione; hydroxylases, which transform estrogens into mitotic and antimitotic derivatives; and sulfotransferases and glucuronidases, which, respectively convert into the biologically inactive sulfates and glucuronides. These enzymatic activities are more intense in the carcinoma than in the normal tissue. Concerning aromatase, the application of antiaromatase agents has been largely developed in the treatment of breast cancer patients, with very positive results. Various studies have shown that the activity levels of these enzymes and their mRNA can be involved as interesting prognostic factors for breast cancer. In conclusion, the application of new antienzymatic molecules can open attractive perspectives in the treatment of hormone-dependent breast cancer.
Hormones in normal and cancerous breast: basic and clinical applications
Authors: Brodie Angela , Russo José , Pasqualini Jorge R.
Published: April 2012

No abstract available
Interaction of dietary polyphenols with molecular signaling pathways of antiestrogen resistance: possible role in breast cancer recurrence
Authors: Aiyer Harini S. , Bouker Kerrie B. , Cook Katherine L. , Facey Caroline O.B. , Hu Rong , Schwartz Jessica L. , Shajahan Ayesha N. , Hilakivi-Clarke Leena , Clarke Robert
Published: April 2012

Breast cancer is the most common cancer diagnosed in women and its global incidence is rising rapidly. Adjuvant hormonal therapy, with antiestrogens (AE) such as tamoxifen and fulvestrant, is highly effective in the treatment of estrogen receptor-positive (ER+) breast cancers and is largely responsible for the increase in survival rates seen in the past four decades. However, nearly 50% of women with ER+ cancer display de novo or acquired resistance to AE therapies. Potential molecular mechanisms driving the resistance phenotype are beginning to be elucidated, allowing further development of more effective therapeutic and preventive strategies to reduce the overall mortality due to breast cancer. Over 70% of breast cancer survivors surveyed report increasing their comsumption of fruits, vegetables, and natural product supplements upon diagnosis. These are rich sources of dietary polyphenols (PPs) that can interact with cell-signaling pathways involved in the development of AE resistance. However, research on mechanisms by which these agents may affect AE resistance and whether PP intake can significantly change breast cancer recurrence is limited. We summarize the available data on the effects of PPs on breast cancer recurrence and the interactions of these compounds with some of the signaling pathways hypothesized to drive cell death and survival involved in the development of AE resistance in breast cancer.
Freistellung von wettbewerbsbeschränkenden Vereinbarungen
Authors: Mohr Jochen , König Carsten
Published: April 2012

Der nachfolgende Beitrag erläutert im Anschluss an die Darstellung des Tatbestands des Verbots wettbewerbsbeschränkender
Vereinbarungen gem. Art. 101 Abs. 1, § 1 GWB in JURA Heft 3/2011 die Freistellung tatbestandlicher Wettbewerbsbeschränkungen gem. Art. 101 Abs. 3 AEUV, § 2 GWB.Ergänzend werden die Rechtsfolgen von Verstößen gegen das Kartellverbot insbesondere gem. § 33 GWB sowie dessen Verhältnis zum Missbrauchsverbot und zur Fusionskontrolle behandelt.
Zurechnungskriterien für Aktionen nicht-staatlicher Gewaltakteure
Authors: Hofmann Tobias
Published: April 2012

Die Problematik der Zurechnung von Handlungen nichtstaatlicher
Akteure gilt als »Klassiker« in völkerrechtlichen
Prüfungsarbeiten. Dieser Beitrag behandelt nun die Frage,
welche Voraussetzungen erfüllt sein müssen, damit einem
Staat Handlungen privater Akteure zugerechnet werden können.
Hierbei werden in einem ersten Schritt die vertretenen
Zurechnungskriterien herausgearbeitet und sodann in einem
zweiten Schritt der Frage nachgegangen, ob sich im Zuge der
Ereignisse des 11. September für den Bereich des internationalen
Terrorismus neue Kriterien entwickelt haben.
Gesetzliche Schuldverhältnisse: Eine Einführung
Authors: Röthel Anne
Published: April 2012

Was sind gesetzliche Schuldverhältnisse, und warum gibt es
sie? Was unterscheidet sie von vertraglichen Schuldverhältnissen,
und worin unterscheiden sie sich untereinander? Welche
Regeln gelten für sämtliche Schuldverhältnisse, und welche gelten nur für gesetzliche oder nur für vertragliche
Schuldverhältnisse? Diese Fragen liegen nahe, lassen sich
aber nicht immer leicht beantworten. Die folgende Einführung
in das Recht der gesetzlichen Schuldverhältnisse will eine
erste Orientierung geben. Der Beitrag richtet sich an Studierende
der ersten Semester.
Eingriffsbefugnisse bei Veranstaltungen
Authors: Trurnit Christoph
Published: April 2012

In unserer Gesellschaft gibt es eine ausgeprägte »Event-Kultur«. Ganz gleich, ob z. B. Massenparty, Sportereignis oder Stadtfest, Veranstaltungen können Probleme für die öffentliche Sicherheit verursachen. Bei der Abwehr von Gefahren im Zusammenhang mit Veranstaltungen müssen die zuständigen Behörden nicht nur besondere einsatztaktische und
psychologische Aspekte berücksichtigen. Es zeigt sich dabei
auch einmal mehr die ungebrochene Aktualität des Allgemeinen
Polizei- und Ordnungsrechts.
Das Verbot des Insiderhandels im Wertpapierhandelsgesetz
Authors: Kretschmer Joachim
Published: April 2012

Wirtschaftsstrafrecht ist oft sog. Nebenstrafrecht. Dazu zählen
auch die Sanktionsvorschriften im WertpapierhandelsG. Der Beitrag beschäftigt sich mit dem Insiderstrafrecht und macht in Grundzügen die Insiderdelikte bekannt. Das Verbot des Insiderhandels ist zudem aktuell, weil derzeit – März 2012 – ehemalige Funktionäre der Schutzgemeinschaft der Kapitalanleger in München wegen einschlägiger Delikte vor Gericht stehen.
Examensklausur ZR Silberhochzeitsreise mit Hindernissen
Authors: Schmidt Jessica
Published: April 2012

Die reiserechtliche Klausur wurde aus Anlass einiger neuer
Entscheidungen des BGH im Wintersemester 2010/11 im Examensklausurenkurs der Friedrich-Schiller-Universität Jena angeboten. Gegenstand sind zum einen klassische Standardprobleme der Haftung des Reiseveranstalters (Reisevertrag als Vertrag zugunsten Dritter bei Familienangehörigen,
vertragliche und deliktische Haftung des Reiseveranstalters, Abgrenzung Eigen- und Fremdleistung, Schadensersatz für nutzlos aufgewendete Urlaubszeit), zum anderen insbesondere Probleme betreffend die Wahrung der Ausschlussfrist des § 651 g BGB.
Barriers to Medication Adherence in HIV-Infected Children and Youth Based on Self- and Caregiver Report
Authors: Buchanan Ashley L. , Montepiedra Grace , Sirois Patricia A. , Kammerer Betsy , Garvie Patricia A. , Storm Deborah S. , Nichols Sharon L.
Published: April 2012

OBJECTIVE:

Nonadherence to antiretroviral therapy among children/youth with HIV often is associated with disease progression. This study examined the agreement between child and caregiver perceptions of barriers to adherence and factors associated with these barriers.

METHODS:

Children/youth with perinatally acquired HIV and their parents/caregivers (n = 120 dyads) completed a questionnaire about 19 potential barriers to adherence to the child’s antiretroviral therapy regimen. Agreement between the 2 reports was measured via the kappa statistic. Factors associated with the barriers were assessed by using multiple logistic regression.

RESULTS:

Of the 120 children, 55% were African American, 54% were boys, and the average age was 12.8 years. The most frequently reported barrier by either the caregiver or youth was “forgot.” There were varying degrees of agreement between child and caregiver on the following barriers: “forgot,” “taste,” “child was away from home,” “child refused,” and “child felt good.” Children who knew their HIV status were more likely to report logistical barriers, such as scheduling issues. Children with a biological parent as their caregiver were more likely to report regimen or fear of disclosure as a barrier.

CONCLUSIONS:

Lack of agreement was observed for more than half of the studied barriers, indicating discrepancies between children’s and caregivers’ perceptions of factors that influence medication-taking. The findings suggest a need for interventions that involve both child and caregiver in the tasks of remembering when to administer the child’s medications, sustaining adherence, and appropriately transitioning medication responsibility to the youth.
Magnesium Use in Asthma Pharmacotherapy: A Pediatric Emergency Research Canada Study
Authors: Schuh Suzanne , Zemek Roger , Plint Amy , Black Karen J. L. , Freedman Stephen , Porter Robert , Gouin Serge , Hernandez Alexandra , Johnson David W.
Published: April 2012

OBJECTIVES:

To examine the use of intravenous magnesium in Canadian pediatric emergency departments (EDs) in children requiring hospitalization for acute asthma and association of administration of frequent albuterol/ipratropium and timely corticosteroids with hospitalization.

METHODS:

Retrospective medical record review at 6 EDs of otherwise healthy children 2 to 17 years of age with acute asthma. Data were extracted on history, disease severity, and timing of ED stabilization treatments with inhaled albuterol, ipratropium, corticosteroids, and magnesium. Primary outcome was the proportion of hospitalized children given magnesium in the ED. Secondary outcome was the ED use of “intensive therapy” in hospitalized children, defined as 3 albuterol inhalations with ipratropium and corticosteroids within 1 hour of triage.

RESULTS:

A total of 19 (12.3%) of 154 hospitalized children received magnesium (95% confidence interval 7.1, 17.5) versus 2 of 962 discharged patients. Children given magnesium were more likely to have been previously admitted to ICU (odds ratio [OR] 11.2), hospitalized within the past year (OR 3.8), received corticosteroids before arrival (OR 4.0), presented with severe exacerbation (OR 6.1), and to have been treated at 1 particular center (OR 14.9). Forty-two (53%) of 90 hospitalized children were not given “intensive therapy.” Children receiving “intensive therapy” were more likely to present with severe disease to EDs by using asthma guidelines (ORs 8.9, 3.0). Differences in the frequencies of all stabilization treatments were significant across centers.

CONCLUSIONS:

Magnesium is used infrequently in Canadian pediatric EDs in acute asthma requiring hospitalization. Many of these children also do not receive frequent albuterol and ipratropium, or early corticosteroids. Significant variability in the use of these interventions was detected.
Automated Primary Care Screening in Pediatric Waiting Rooms
Authors: Anand Vibha , Carroll Aaron E. , Downs Stephen M.
Published: April 2012

BACKGROUND AND OBJECTIVE:

Implementing US Preventive Services Task Force and American Academy of Pediatrics preventive service guidelines within the short duration of a visit is difficult because identifying which of a large number of guidelines apply to a particular patient is impractical. Clinical decision support system integrated with electronic medical records offer a good strategy for implementing screening in waiting rooms. Our objective was to determine rates of positive risk screens during typical well-care visits among children and adolescents in a primary care setting.

METHODS:

Child Health Improvement through Computer Automation (CHICA) is a pediatric clinical decision support system developed by our research group. CHICA encodes clinical guidelines as medical logic modules to generate scanable paper forms: the patient screening form to collect structured data from patient families in the waiting room and the physician worksheet to provide physician assessments at each visit. By using visit as a unit of analysis from CHICA’s database, we have determined positive risk screen rates in our population.

RESULTS:

From a cohort of 16 963 patients, 408 601 questions were asked in 31 843 visits. Of the questions asked, 362 363 (89%) had a response. Of those, 39 176 (11%) identified positive risk screens in both the younger children and the adolescent age groups.

CONCLUSIONS:

By automating the process of screening and alerting the physician to those who screened positive, we have significantly decreased the burden of identifying relevant guidelines and screening of patient families in our clinics.
Birth Asphyxia: A Major Cause of Early Neonatal Mortality in a Tanzanian Rural Hospital
Authors: Ersdal Hege Langli , Mduma Estomih , Svensen Erling , Perlman Jeffrey
Published: April 2012

OBJECTIVE:

Early neonatal mortality within the first 24 hours contributes substantially to overall neonatal mortality rates. The definition of birth asphyxia (BA) is imprecise, and reliable cause-specific mortality data are limited; thus the estimated proportion of BA-related deaths globally remains questionable. The objective was to determine the presumed causes of neonatal death within the first 24 hours in a rural hospital in Northern Tanzania.

METHODS:

This is a prospective descriptive observational study conducted in the delivery room and adjacent neonatal area. Research assistants were trained to observe and record events related to labor, neonatal resuscitation, and 24-hour postnatal course. BA was defined as failure to initiate spontaneous respirations and/or 5-minute Apgar score <7, prematurity as gestational age <36 weeks, and low birth weight (LBW) as birth weight <3rd centile for gestational age. Data were analyzed with χ2 and Student’s t tests.

RESULTS:

Over 1 year, 4720 infants were born and evaluated. Of these, 256 were admitted to the neonatal area. Forty-nine infants died secondary to BA (61%), prematurity (18%), LBW (8%), infection (2%), congenital abnormalities (8%), and unclear reason (2%). The 5-minute Apgar score was ≥7 in 50% of the infants who died secondary to BA.

CONCLUSIONS:

Most cases of early neonatal mortality were related to BA, and prematurity and LBW are additional important considerations. Reducing perinatal mortality requires a multifaceted approach with attention to issues related to BA, potential complications of prematurity, and LBW. The 5-minute Apgar score is a poor surrogate of BA.
Ground improvements in Haneda/Tokyo International Airport expansion project
Authors: Kitazume Masaki
Published: April 2012

Haneda/Tokyo International Airport was established in 1931 as the first primary airport in Japan where a runway of 300 m was operated. The airport has been expanded several times and the current airport has three runways and two terminal buildings on the man-made island. In order to cope with the future increase in air transportation, the fourth runway was constructed on a man-made island to the south of the existing airfield in 2010. As soft soil strata were stratified at the construction site, several ground improvement techniques were employed to improve the ground. As the project site was adjacent to the current airport, a large part of the construction site was regulated as a restricted area under the Civil Aeronautics Act of Japan. Under the limitation, the construction project had to be progressed under a very tight schedule. In this paper, the application of the ground improvement techniques is briefly introduced as well as an outline of the construction project.
Evaluation of contrast metrics for liquid‐crystal displays under different viewing conditions
Authors: Lu Weige , Xu Haisong , Luo M. Ronnier
Published: April 2012

Abstract— A psychophysical experiment was carried out to assess the perceptual contrast on a large‐sized liquid‐crystal display (LCD) under nine phases of viewing conditions. Based on the results, six contrast models employing different color attributes or the index of just‐noticeable difference (JND) were developed. Their performances were also tested by the visual data of the nine phases, which indicated that the model CQ employing CIECAM02 brightness gives the best performance in predicting visual data under different viewing conditions among those models. A preprocessing step was also proposed to utilize the contrast model CQ conveniently in the practical contrast evaluation of LCDs.
V‐shaped electro‐optical mode based on deformed‐helix ferroelectric liquid crystal with subwavelength pitch
Authors: Pozhidaev Eugene , Chigrinov Vladimir , Murauski Anatoli , Molkin Vadim , Tao Du , Kwok Hoi‐Sing
Published: April 2012

Abstract— V‐shaped electro‐optical response is shown, both theoretically and experimentally, to be an inherent property of a deformed‐helix ferroelectric liquid‐crystal cell (DHFLC) under a special choice of the applied rectangular alternating‐electric‐field waveform, frequency, and cell geometry. In contrast to other known V‐shaped ferroelectric liquid‐crystal (FLC) modes, the discovered V‐shaped switching is observed in a broadband frequency range including 1 kHz, and not at a certain characteristic frequency. This type of V‐shaped switching allows for a drastic increase in the operating frequency of field‐sequential‐color (FSC) LCD cells in comparison with fast nematic liquid‐crystal (NLC) modes.
Changes in seed dispersal processes and the potential for between‐patch connectivity for an arid land daisy
Authors: Emmerson Louise M. , Facelli José M. , Chesson Peter , Possingham Hugh , Day Jemery R.
Published: April 2012

Dispersal is a major and critical process in population biology that has been particularly challenging to study. Animals can have major roles in seed dispersal even in species that do not appear specifically adapted to animal‐aided dispersal. This can occur by two processes: direct movement of diaspores by animals and modification of landscape characteristics by animals in ways that greatly influence dispersal. We exploited the production of large, persistent dispersal structures (seed heads, henceforth) by Erodiophyllum elderi (Asteraceae), a daisy from arid Australia, to further understand secondary dispersal. Seed head dispersal on and off animal tracks in eight E. elderi patches was monitored for 9.5 months by periodically recording the location of marked seed heads. Sites were located inside a reserve that excludes sheep but not kangaroos, and in a nearby area with both kangaroos and sheep. The distance moved and likelihood of seed head movement was higher in areas with sheep, and especially along animal tracks. There was clear evidence that seed heads were channeled down animal tracks during large rainfall events. Seed head dispersal away from patches occurred to a limited extent via their physical contact with sheep and potentially via wind dispersal. Thus, the advantages of this study system allowed us to demonstrate the two postulated effects of herbivores on dispersal via direct movement of seed heads, and two distinct indirect effects through landscape modification by herbivores from the creation of animal tracks and the denudation of vegetation.
Postdispersal seed predation limits the abundance of a long‐lived perennial forb (Lithospermum ruderale)
Authors: Bricker Mary , Maron John
Published: April 2012

Loss of seeds to consumers is common in plant communities, but the degree to which these losses influence plant abundance or population growth is often unclear. This is particularly the case for postdispersal seed predation by rodents, as most studies of rodent seed predation have focused on the sources of spatiotemporal variation in seed loss but not quantified the population consequences of this loss. In previous work we showed that seed predation by deer mice (Peromyscus maniculatus) substantially reduced seedling recruitment and establishment of Lithospermum ruderale (Boraginaceae), a long‐lived perennial forb. To shed light on how rodent seed predation and the near‐term effects on plant recruitment might influence longer‐term patterns of L. ruderale population growth, we combined experimental results with demographic data in stage‐based population models. Model outputs revealed that rodent seed predation had a significant impact on L. ruderale population growth rate (λ). With the removal of postdispersal seed predation, the projected population growth rates increased between 0.06 and 0.12, depending on site (mean Δλ across sites = 0.08). Seed predation shifted the projected stable stage distribution of populations from one with a high proportion of young plants to one in which larger adult size classes dominate. Elasticities of vital rates also changed, with germination and growth of seedlings and young plants becoming more important with the removal of seed predation. Simulations varying the magnitude of seed predation pressure while holding other vital rates constant showed that seed predation could lower λ even if only 40% of available seeds were consumed. These results demonstrate that rodent granivory can be a potent force limiting the abundance of a long‐lived perennial forb.
A power–efficiency trade‐off in resource use alters epidemiological relationships
Authors: Hall Spencer R. , Becker Claes R. , Duffy Meghan A. , Cáceres Carla E.
Published: April 2012

Trade‐offs play pivotal roles in the ecology and evolution of natural populations. However, trade‐offs are probably not static, invariant relationships. Instead, ecological factors can shift, alter, or reverse the relationships underlying trade‐offs and create critical genotype × environment (G × E) interactions. But which ecological factors alter trade‐offs or create G × E interactions, and why (mechanistically) do they do this? We tackle these questions using resource quality as the central ecological factor and a case study of disease in the plankton. We show that clonal genotypes of a zooplankton host (Daphnia dentifera) exhibit a “power–efficiency” trade‐off in resource use, where powerful (fast‐feeding) host clones perform well on richer algal resources, but more efficient (slow‐feeding) clones perform relatively well on poorer resources. This resource‐based trade‐off then influences epidemiological relationships due to fundamental connections between resources and fecundity, transmission rate (an index of resistance), and replication of a virulent fungal parasite (Metschnikowia bicuspidata) within hosts. For instance, using experiments and dynamic energy budget models, we show that the power–efficiency trade‐off overturned a previously detected trade‐off between fecundity and transmission risk of hosts to this parasite. When poorer resources were eaten, transmission risk and fecundity were negatively, not positively, correlated. Additionally, poor resource quality changed positive relationships between yield of infectious stages (spores) and host fecundity: those fecundity–spore relationships with poor food became negative or nonsignificant. Finally, the power–efficiency trade‐off set up an interaction between host clone and resource quality for yield of fungal spores: powerful clones yielded relatively more spores on the better resource, while efficient clones yielded relatively more on the poorer resource. Thus, the physiological ecology of resource use can offer potent, mechanistic insight linking environmental factors to epidemiological relationships.