bluuebunny/crossref_metadata_2025 huggingface dataset:
Metallothionein expression in chloroplasts enhances mercury accumulation and phytoremediation capability
Authors: Ruiz Oscar N. , Alvarez Derry , Torres Cesar , Roman Laura , Daniell Henry
Published: April 2011

Genetic engineering to enhance mercury phytoremediation has been accomplished by expression of the merAB genes that protects the cell by converting Hg[II] into Hg[0] which volatilizes from the cell. A drawback of this approach is that toxic Hg is released back into the environment. A better phytoremediation strategy would be to accumulate mercury inside plants for subsequent retrieval. We report here the development of a transplastomic approach to express the mouse metallothionein gene (mt1) and accumulate mercury in high concentrations within plant cells. Real‐time PCR analysis showed that up to 1284 copies of the mt1 gene were found per cell when compared with 1326 copies of the 16S rrn gene, thereby attaining homoplasmy. Past studies in chloroplast transformation used qualitative Southern blots to evaluate indirectly transgene copy number, whereas we used real‐time PCR for the first time to establish homoplasmy and estimate transgene copy number and transcript levels. The mt1 transcript levels were very high with 183 000 copies per ng of RNA or 41% the abundance of the 16S rrn transcripts. The transplastomic lines were resistant up to 20 μm mercury and maintained high chlorophyll content and biomass. Although the transgenic plants accumulated high concentrations of mercury in all tissues, leaves accumulated up to 106 ng, indicating active phytoremediation and translocation of mercury. Such accumulation of mercury in plant tissues facilitates proper disposal or recycling. This study reports, for the first time, the use of metallothioniens in plants for mercury phytoremediation. Chloroplast genetic engineering approach is useful to express metal‐scavenging proteins for phytoremediation.
Assessing the utility of 210Pb geochronology for estimating sediment accumulation rates on river floodplains in Fiji
Authors: Terry James P. , Lal Rajeev , Garimella Sitaram
Published: April 2011

Low‐energy gamma ray spectroscopy has been employed to estimate floodplain sedimentation rates using measurements of 210Pb in floodplain alluvium. The utility of the technique is assessed through the analysis of excess (unsupported) 210Pb profiles in three sediment cores taken from the floodplain of the Labasa River on Vanua Levu in northern Fiji. A low‐energy germanium spectrometer (LEGe) was used for the nondestructive determination of excess 210Pb in a region cultivated intensively with sugarcane. Measured average historical (c. 25 years) vertical accretion rates are between 2.2 and 4.4 cm yr−1. The findings are broadly comparable with published sedimentation rates from analyses of radionuclide profiles elsewhere in the tropical South Pacific Islands, but the rates are higher than those measured previously at the same Labasa River sites using 137Cs profiles. Accelerated soil erosion owing to cane burning and land tillage seems to be largely responsible for sediment production, although flood‐related effects such as channel accretion by coarse bedload and the emplacement of large organic debris also influence floodplain sedimentation. However, application of the 210Pb technique in Fiji (and perhaps neighbouring island countries) is found to have serious drawbacks compared to the more robust 137Cs method, owing principally to the low 210Pb concentrations in the sandy alluvial sediment tested.
Spaces of uncertainty: A model of mobile space in the Sahel
Authors: Retaillé Denis , Walther Olivier
Published: April 2011

This paper presents a model of mobile space in the Sahel based on the two logics of circulation and production. An overview of the epistemological origins of the model shows how spatial structuring in (and of) the Sahel has been progressively transformed by the territorial action of economic actors, colonial powers, states and development programmes. The particular focus is on nomadic and cross‐border spaces – configurations that offer an ideal perspective on the mobility of space. The model confirms the hypothesis that economic actors, states and development agencies all aim to improve the way uncertainty is managed, but remain profoundly divided over what strategies to adopt. Whereas free flows allow economic actors to obtain products wherever these may be available, states and development agencies conceive of territory as a resource that must drive the specialization of production. The proposed model also suggests that mobile space is not peculiar to the Sahel and that the spatial logics of circulation and production in the Sahel are also present in the process of globalization. It provides conceptual resources that could lead to other models potentially applicable to understanding uncertainty in a highly mobile, globalized world.
Globalization, economic crisis and Africa's informal economy women workers
Authors: Johnston‐Anumonwo Ibipo , Doane Donna L.
Published: April 2011

The processes of globalization and debt crisis led to dramatic changes in African countries. In the context of a new economic crisis – now on a global scale – it is useful to revisit debates regarding the impact of earlier policies in response to economic crisis on the poor, with a focus on very low‐income informal women workers. In this paper, we adopt a gender analysis framework to examine contending perspectives about the differential impacts of globalization, liberalization and structural adjustment programs on African women and men. We comment on two predominant schools of thought that appear to underlie and define the majority of case studies situated in African countries. While one asserts that globalization and liberalization offer entrepreneurial opportunities for women, an opposing view contends that the neoliberal political and economic reforms connected with structural adjustment policies have been devastating for poor women workers. A review of available empirical research on the responses of informal economy women workers to challenges of increased workload, reduced income and curtailed access to social services, cautions against dogmatic adherence to conceptual perspectives that either assume workers in the informal economy to be dynamic entrepreneurs when they cannot be, or condemn only contemporary policies for conditions that are the product of complex historical processes.
Livelihoods and the transformative potential of cities: Challenges of inclusive development in Rustenburg, North West Province, South Africa
Authors: Mosiane Ben
Published: April 2011

Urban geographers increasingly incorporate the potential of so‐called informal livelihood activities to provide resources that can be creatively managed in the transformation of urban space, particularly to the benefit of less well off and marginalized residents. This paper reports a case study in Rustenburg, North West Province, South Africa, where city managers began to promote inclusive development in the early 1990s, just prior to the formal dismantling of the apartheid system. The findings reveal that Rustenburg's urban transformation process, over a decade later, continued to reproduce repressive practices that limit the informal livelihood activities of the urban majority. Apparently efforts of well‐meaning city managers to implement a sustainable and inclusive development process are often rendered futile at the point of actually defining the constituents of urban socioeconomic transformation.
Diagnostic tools in beta regression with varying dispersion
Authors: Ferrari Silvia L. P. , Espinheira Patricia L. , Cribari‐Neto Francisco
Published: April 2011

We consider the issue of performing residual and local influence analyses in beta regression models with varying dispersion, which are useful for modelling random variables that assume values in the standard unit interval. In such models, both the mean and the dispersion depend upon independent variables. We derive the appropriate matrices for assessing local influence on the parameter estimates under different perturbation schemes. An application using real data is presented and discussed.
A wavelet‐based spectral method for extracting self‐similarity measures in time‐varying two‐dimensional rainfall maps
Authors: Ramírez‐Cobo Pepa , Lee Kichun Sky , Molini Annalisa , Porporato Amilcare , Katul Gabriel , Vidakovic Brani
Published: April 2011

Many environmental time‐evolving spatial phenomena are characterized by a large number of energetic modes, the occurrence of irregularities, and self‐organization over a wide range of space or time scales. Precipitation is a classical example characterized by both strong intermittency and multiscale dynamics, and these features generate persistence, long‐range dependence, and extremes (whether be it droughts or extreme floods). Over the last two decades, time‐frequency or time‐scale transforms have become indispensable tools in the analysis of such phenomena and, as a consequence, a number of wavelet‐based spectral methods are now routinely employed to estimate Hurst exponents and other measures of regularity and scaling. In this article, an ensemble of new wavelet‐based spectral tools for analysis of 2‐D images is proposed. The new scale‐mixing wavelet spectrum is applied to the analysis of time sequences of two‐dimensional spatial rainfall radar images characterized by either convective or frontal systems. Intermittent spatial patterns connected to the precipitation‐formation mechanisms were encoded in low‐dimensional informative descriptors appropriate for classification, discrimination analyses and possible integration with climate models. We found that convective rainfall spatial patterns compared to frontal patterns produce spectral signatures consistent with their generation mechanism.
Frequency and phase estimation in time series with quasi periodic components
Authors: Paraschakis Konstantinos , Dahlhaus Rainer
Published: April 2011

In this article, we consider frequency and phase estimation in a noisy oscillation with potentially non‐constant phase increments resulting from an underlying non‐constant frequency. A maximum periodogram method on segments is used to estimate the time‐varying frequency and a subsequent least squares approach to estimate the phase. A key problem addressed in this article is the question how to set up a meaningful concept of asymptotic statistics for this model. This problem is solved by a special infill asymptotics concept. We use this concept to prove consistency and asymptotic normality of the estimates. Furthermore, the phase estimate is compared to the Hilbert transform in a simulation.
Optimizing the operating conditions in a high precision industrial process using soft computing techniques
Authors: Corchado Emilio , Sedano Javier , Curiel Leticia , Villar José R.
Published: April 2011

This interdisciplinary research is based on the application of unsupervized connectionist architectures in conjunction with modelling systems and on the determining of the optimal operating conditions of a new high precision industrial process known as laser milling. Laser milling is a relatively new micro‐manufacturing technique in the production of high‐value industrial components. The industrial problem is defined by a data set relayed through standard sensors situated on a laser‐milling centre, which is a machine tool for manufacturing high‐value micro‐moulds, micro‐dies and micro‐tools. The new three‐phase industrial system presented in this study is capable of identifying a model for the laser‐milling process based on low‐order models. The first two steps are based on the use of unsupervized connectionist models. The first step involves the analysis of the data sets that define each case study to identify if they are informative enough or if the experiments have to be performed again. In the second step, a feature selection phase is performed to determine the main variables to be processed in the third step. In this last step, the results of the study provide a model for a laser‐milling procedure based on low‐order models, such as black‐box, in order to approximate the optimal form of the laser‐milling process. The three‐step model has been tested with real data obtained for three different materials: aluminium, cooper and hardened steel. These three materials are used in the manufacture of micro‐moulds, micro‐coolers and micro‐dies, high‐value tools for the medical and automotive industries among others. As the model inputs are standard data provided by the laser‐milling centre, the industrial implementation of the model is immediate. Thus, this study demonstrates how a high precision industrial process can be improved using a combination of artificial intelligence and identification techniques.
Clinical and imaging features of Othello’s syndrome
Authors: Graff‐Radford J. , Whitwell J. L. , Geda Y. E. , Josephs K. A.
Published: April 2011

Background and Purpose:  Our objective was to document the clinical and imaging features of Othello’s syndrome (delusional jealousy).

Methods:  The study design was a retrospective case series of 105 patients with Othello’s syndrome that were identified using the Electronic Medical Record system of Mayo Clinic.

Results:  The average age at onset of Othello’s syndrome was 68 (25–94) years with 61.9% of patients being male. Othello’s syndrome was most commonly associated with a neurological disorder (73/105) compared with psychiatric disorders (32/105). Of the patients with a neurological disorder, 76.7% had a neurodegenerative disorder. Seven of eight patients with a structural lesion associated with Othello’s syndrome had right frontal lobe pathology. Voxel‐based morphometry showed greater gray matter loss predominantly in the dorsolateral frontal lobes in the neurodegenerative patients with Othello’s compared to matched patients with neurodegenerative disorders without Othello’s syndrome. Treatment success was notable for patients with dopamine agonist induced Othello’s syndrome in which all six patients had improvement in symptoms following decrease in medication.

Conclusions:  This study demonstrates that Othello’s syndrome occurs most frequently with neurological disorders. This delusion appears to be associated with dysfunction of the frontal lobes, especially the right frontal lobe.
When persons disagree: An ERP study of Unagreement in Spanish
Authors: Mancini Simona , Molinaro Nicola , Rizzi Luigi , Carreiras Manuel
Published: April 2011

Agreement is one of the main devices used by languages to signal grammatical relations. In this study, we investigated the neurophysiological processing correlates of subject‐verb agreement in Spanish using Unagreement, a phenomenon characterized by a person mismatch between subject and verb that nonetheless produces a grammatical pattern. Unagreement was compared to well‐formed sentences with full agreement, and ill‐formed sentences with a person mismatch. Compared to control sentences, Unagreement produced a left posterior negativity followed by a more central negativity; no P600 effect was observed. In contrast, person violations generated a negativity that was widely distributed over the scalp, followed by a P600 effect. These data suggest that the comprehension of qualitatively different agreement patterns, which could reflect the performance of different processing routines, recruits different neural generators.
Determination of allele frequencies of growth hormone AluI polymorphism in Brown Swiss, Holstein, native East Anatolian Red and Turkish Grey breeds
Authors: ÖZDEMIR MEMIS
Published: April 2011

A total of 177 cattle of four breeds were genotyped for the bovine growth hormone (BGH)‐AluI polymorphism by polymerase chain reaction‐restriction fragment length polymorphism (PCR‐RFLP). The genotype and gene frequencies for each breed were determined and tested to be in Hardy–Weinberg equilibrium. According to breeds, frequencies of allele L gene were 0.905 for Brown Swiss, 0.898 for Holstein, 0.976 for East Anatolian Red and 0.893 for Turkish Grey Breeds. The allele L was predominant and variant VV was not detected in the breeds studied. BGH‐AluI genotypes were found to be in equilibrium within and among breeds.
An assessment of the texture of acidified sodium caseinate gels with added inulin using response surface methodology
Authors: PICONE CAROLINA S F , MAXIMO GUILHERME J , KUHN KÁTIA R , ROS‐POLSKI VALQUÍRIA , CUNHA ROSIANE L
Published: April 2011

This work evaluated the effect of inulin concentration (0–6.0% w/w) on the mechanical properties and microstructure of gels composed of sodium caseinate (CN) (1.5–6.5% w/w) at pH 4.6. Inulin did not statistically affect the elastic modulus and rupture properties of the studied gels but affected the nonlinear mechanical behaviour. Samples with higher inulin concentrations (6% w/w) presented strain‐weakening deformation behaviour, whilst gels with lower inulin concentrations were strain hardening. The presence of inulin resulted in a more closed‐pores network. Gel deformability increased as CN concentration was enhanced, reaching a maximum of 0.60 at 5.58% (w/w) CN, but was not affected by inulin concentration.
Mitochondrial aconitase knockdown attenuates paraquat‐induced dopaminergic cell death via decreased cellular metabolism and release of iron and H2O2
Authors: Cantu David , Fulton Ruth E. , Drechsel Derek A. , Patel Manisha
Published: April 2011

J. Neurochem. (2011) 10.1111/j.1471‐4159.2011.07290.x

Mitochondrial oxidative stress is a contributing factor in the etiology of numerous neuronal disorders. However, the precise mechanism(s) by which mitochondrial reactive oxygen species modify cellular targets to induce neurotoxicity remains unknown. In this study, we determined the role of mitochondrial aconitase (m‐aconitase) in neurotoxicity by decreasing its expression. Incubation of the rat dopaminergic cell line, N27, with paraquat (PQ2+) resulted in aconitase inactivation, increased hydrogen peroxide (H2O2) and increased ferrous iron (Fe2+) at times preceding cell death. To confirm the role of m‐aconitase in dopaminergic cell death, we knocked down m‐aconitase expression via RNA interference. Incubation of m‐aconitase knockdown N27 cells with PQ2+ resulted in decreased H2O2 production, Fe2+ accumulation, and cell death compared with cells expressing basal levels of m‐aconitase. To determine the metabolic role of m‐aconitase in mediating neuroprotection, we conducted a complete bioenergetic profile. m‐Aconitase knockdown N27 cells showed a global decrease in metabolism (glycolysis and oxygen consumption rates) which blocked PQ2+‐induced H+ leak and respiratory capacity deficiency. These findings suggest that dopaminergic cells are protected from death by decreasing release of H2O2 and Fe2+ in addition to decreased cellular metabolism.
Insulin receptor substrate chico acts with the transcription factor FOXO to extend Drosophila lifespan
Authors: Yamamoto Rochele , Tatar Marc
Published: April 2011

Although extensively studied in Caenorhabditis elegans, no work has yet demonstrated for Drosophila melanogaster whether reduced insulin/IGF signaling (IIS) requires the FOXO transcription factor (foxo) to extend lifespan. Here, we conduct genetic epistasis analysis to determine whether foxo is required for chico mutants (insulin receptor substrate) to reduce age‐specific mortality and thus extend lifespan. The mutant chico1 allele strongly extends lifespan relative to wild‐type sibs. A mutant of foxo eliminates most of this chico survival benefit. In addition, we used a factorial proportional hazard analysis to formally study the main effects of chico and of foxo and to determine how these genes interact to influence mortality. We document that foxo indeed contributes to how chico increases lifespan, but part of the convergence in survival between chico genotypes in the foxo‐mutant background may occur because chico mutation exacerbates the negative effects of foxo mutation.
Effects of age on parathyroid hormone signaling in human marrow stromal cells
Authors: Zhou Shuanhu , Bueno Ericka M. , Kim Sung Won , Amato Ilaria , Shen Longxiang , Hahne Jochen , Bleiberg Ilan , Morley Paul , Glowacki Julie
Published: April 2011

Human bone marrow stromal cells (hMSCs) have the potential to differentiate into osteoblasts; there are age‐related decreases in their proliferation and differentiation to osteoblasts. Parathyroid hormone (PTH), when applied intermittently in vivo, has osteoanabolic effects in a variety of systems. In this study, we compared PTH signaling and osteoanabolic effects in hMSCs from young and old subjects. There were age‐related decreases in expression of PTH/PTHrP receptor type 1 (PTHR1) gene (P = 0.049, n = 19) and in PTH activation of CREB (P = 0.029, n = 7) and PTH stabilization of β‐catenin (P = 0.018, n = 7). Three human PTH peptides, PTH1‐34, PTH1‐31C (Ostabolin‐C, Leu27, Cyclo[Glu22‐Lys26]‐hPTH1‐31), and PTH1‐84 (10 nm), stimulated osteoblast differentiation with hMSCs. Treatment with PTH1‐34 resulted in a significant 67% increase in alkaline phosphatase activity in hMSCs obtained from younger subjects (<50 years old, n = 5), compared with an 18% increase in hMSCs from elders (>55 years old, n = 7). Both knockdown of CREB and treatment with a protein kinase A inhibitor H‐89 blocked PTH stimulation of osteoblast differentiation in hMSCs from young subjects. The PTH peptides significantly stimulated proliferation of hMSCs. Treatment with PTH1‐34 resulted in an average of twice as many cells in cultures of hMSCs from young subjects (n = 4), but had no effect with hMSCs from elders (n = 7). Upregulation of PTHR1 by 24‐h pretreatment with 100 nm dexamethasone rescued PTH stimulation of proliferation in hMSCS from elders. In conclusion, age‐related intrinsic alterations in signaling responses to osteoanabolic agents like PTH may contribute to cellular and tissue aging of the human skeleton.
Comparative biology of mammalian telomeres: hypotheses on ancestral states and the roles of telomeres in longevity determination
Authors: Gomes Nuno M. V. , Ryder Oliver A. , Houck Marlys L. , Charter Suellen J. , Walker William , Forsyth Nicholas R. , Austad Steven N. , Venditti Chris , Pagel Mark , Shay Jerry W. , Wright Woodring E.
Published: April 2011

Progressive telomere shortening from cell division (replicative aging) provides a barrier for human tumor progression. This program is not conserved in laboratory mice, which have longer telomeres and constitutive telomerase. Wild species that do/do not use replicative aging have been reported, but the evolution of different phenotypes and a conceptual framework for understanding their uses of telomeres is lacking. We examined telomeres/telomerase in cultured cells from > 60 mammalian species to place different uses of telomeres in a broad mammalian context. Phylogeny‐based statistical analysis reconstructed ancestral states. Our analysis suggested that the ancestral mammalian phenotype included short telomeres (< 20 kb, as we now see in humans) and repressed telomerase. We argue that the repressed telomerase was a response to a higher mutation load brought on by the evolution of homeothermy. With telomerase repressed, we then see the evolution of replicative aging. Telomere length inversely correlated with lifespan, while telomerase expression co‐evolved with body size. Multiple independent times smaller, shorter‐lived species changed to having longer telomeres and expressing telomerase. Trade‐offs involving reducing the energetic/cellular costs of specific oxidative protection mechanisms (needed to protect < 20 kb telomeres in the absence of telomerase) could explain this abandonment of replicative aging. These observations provide a conceptual framework for understanding different uses of telomeres in mammals, support a role for human‐like telomeres in allowing longer lifespans to evolve, demonstrate the need to include telomere length in the analysis of comparative studies of oxidative protection in the biology of aging, and identify which mammals can be used as appropriate model organisms for the study of the role of telomeres in human cancer and aging.
Relational uncertainty and cortisol responses to hurtful and supportive messages from a dating partner
Authors: PRIEM JENNIFER S. , SOLOMON DENISE H.
Published: April 2011

This article evaluates theoretical claims linking relational uncertainty to experiences of stress during interactions with a partner. Two observational studies were conducted to evaluate the association between relational uncertainty and salivary cortisol in the context of hurtful and supportive interactions. In Study 1, participants (N = 89) engaged in a conversation about core traits or values with a partner, who was trained to be hurtful. In Study 2, participants (N = 89) received supportive messages after completing a series of stressful tasks and receiving negative performance feedback. As predicted, partner uncertainty was associated with greater cortisol reactivity to the hurtful interaction in Study 1. Contrary to expectations, Study 1 results also indicated that self uncertainty was associated with less cortisol reactivity, when self, partner, and relationship uncertainty were tested in the same model. Study 2 revealed that relational uncertainty dampened cortisol reactions to performing poorly on tasks while the partner observed. As predicted, Study 2 also found that partner uncertainty was associated with less cortisol recovery after the supportive interaction, but neither self nor relationship uncertainty was associated with rate of cortisol change during the recovery period.
The grandparent–grandchild relationship in childhood and adulthood: A matter of continuation?
Authors: GEURTS TEUN , VAN TILBURG THEO G. , POORTMAN ANNE‐RIGT
Published: April 2011

This study examined whether grandparents perceive adult grandchildren as frequent and important contacts by analyzing network membership. It additionally examined whether this network membership is related to relationship intensity during childhood. Network membership was assessed in 1992 (397 grandparents, 1,594 adult grandchildren) and at the 2005–2006 follow‐up (155 grandparents, 429 adult grandchildren) from the Longitudinal Aging Study Amsterdam. Relationship intensity during childhood was assessed in 1992. One out of 4 grandparents identified at least 1 adult grandchild in their personal network. Adult grandchildren who had an intense relationship with their grandparents during childhood were more often in grandparents' network than others. An intense relationship during childhood promotes continuation of the relationship into adulthood and might contribute to grandparent's support potential.
The value of routine ferritin measurement in blood donors
Authors: O'Meara Alix , Infanti Laura , Stebler Christine , Ruesch Morven , Sigle Joerg‐Peter , Stern Martin , Buser Andreas
Published: April 2011

BACKGROUND: Iron store deficiency is a common side effect of whole blood donation. Early recognition and reversal of excessive iron loss may avoid symptomatic iron store depletion in blood donors and reduce volunteer loss due to iron deficiency (ID) anemia.

STUDY DESIGN AND METHODS: Between 1996 and 2009, a total of 160,612 visits with the intention to donate blood by 23,557 healthy volunteers were recorded at our center. As of 2004, routine serum ferritin testing and additional counseling of donors at risk for donation‐induced anemia were implemented. We analyzed the impact of this measure on the hemoglobin (Hb) levels and anemia occurrence in our donor population and in particular in women of childbearing age. Donation rejections due to low Hb counts, the intervals to next donation, and return rates thereafter were also assessed.

RESULTS: The introduction of routine serum ferritin analysis resulted in an increase of mean Hb levels in blood donors particularly in women of childbearing age. The incidence of predonation anemia and donation ineligibility due to a low Hb concentration decreased significantly. The return intervals of donors rejected on account of low Hb levels were shortened; however, the return rates thereafter were also curtailed.

CONCLUSIONS: Systematic serum ferritin measurements allowed an optimized management of ID in our donors and efficacious prevention of ID anemia.
Managerial Discretion and Corporate Governance in Publicly Traded Firms: Evidence From the Property–Liability Insurance Industry
Authors: Miller Steve M.
Published: April 2011

Abstract

We study the incremental impact of corporate governance in mitigating managerial discretion, controlling for incentive alignment of managerial ownership. We extend the managerial discretion hypothesis to predict that for firms with the same set of governance tools, those that utilize governance tools more stringently to control agency costs will command greater contracting cost advantages, leading them to specialize in business with greater managerial discretion. Using 72 publicly traded insurers from 1994 to 2006, we find evidence supporting our hypothesis. Our findings complement the finance literature that focuses on the role of financing policies in mitigating agency costs of managerial discretion.
CEO Turnover and Ownership Structure: Evidence From the U.S. Property–Liability Insurance Industry
Authors: He Enya , Sommer David W.
Published: April 2011

Abstract

This article examines the impact of ownership structure on the relation between firm performance and chief executive officer (CEO) turnover in the U.S. property–liability insurance industry. Theoretical implications of stock versus mutual ownership structures on the performance–turnover relation are ambiguous. Our empirical results indicate that CEO turnover is less responsive to firm underwriting performance in mutual insurers compared to stock insurers. In fact, we find that while CEO turnover for stock firms is negatively related to prior performance, no such relationship is found for mutual insurers. These results hold while controlling for board structure and other relevant factors.
Toward a Global Convergence of Interests
Authors: BIJIAN ZHENG
Published: April 2011

The G‐20 supplanted the G‐8 as the executive committee of globalization as the emerging and advanced economies came together in the wake of the Wall Street crash to stave off depression. Now, each country is going its own way.

In this section we examine whether the G‐20 can be saved, and what the countries within it must do to bring the global economy into balance.
Where the G‐20 Stands
Authors: STIGLITZ JOE
Published: April 2011

The G‐20 supplanted the G‐8 as the executive committee of globalization as the emerging and advanced economies came together in the wake of the Wall Street crash to stave off depression. Now, each country is going its own way.

In this section we examine whether the G‐20 can be saved, and what the countries within it must do to bring the global economy into balance.
How to Get America Back on Track
Authors: MOYO DAMBISA
Published: April 2011

The G‐20 supplanted the G‐8 as the executive committee of globalization as the emerging and advanced economies came together in the wake of the Wall Street crash to stave off depression. Now, each country is going its own way.

In this section we examine whether the G‐20 can be saved, and what the countries within it must do to bring the global economy into balance.
Prepare to Compete with the Muslim Brotherhood
Authors: ALI AYAAN HIRSI
Published: April 2011

The Great Arab Revolt of 2011 has moved swiftly from the peaceful overthrow of autocrats in the nation‐states of Tunisia and Egypt to brutal repression in the tribal societies of Libya, Syria, Bahrain and Yemen.

Meanwhile, the wired youth bulge of the Middle East that brought change is dissipating into an impotent diaspora while the organized interests of the old regimes and the once‐suppressed Islamists charge ahead to power. This section examines the revolt, the reaction and the power struggles in its aftermath.
Behind the Scenes of France's Lead on Libya
Authors: LÉVY BERNARD‐HENRI
Published: April 2011

The Great Arab Revolt of 2011 has moved swiftly from the peaceful overthrow of autocrats in the nation‐states of Tunisia and Egypt to brutal repression in the tribal societies of Libya, Syria, Bahrain and Yemen.

Meanwhile, the wired youth bulge of the Middle East that brought change is dissipating into an impotent diaspora while the organized interests of the old regimes and the once‐suppressed Islamists charge ahead to power. This section examines the revolt, the reaction and the power struggles in its aftermath.
The Tunisian Revolt: Where Have All the Islamists Gone?
Authors: ROY OLIVIER
Published: April 2011

The Great Arab Revolt of 2011 has moved swiftly from the peaceful overthrow of autocrats in the nation‐states of Tunisia and Egypt to brutal repression in the tribal societies of Libya, Syria, Bahrain and Yemen.

Meanwhile, the wired youth bulge of the Middle East that brought change is dissipating into an impotent diaspora while the organized interests of the old regimes and the once‐suppressed Islamists charge ahead to power. This section examines the revolt, the reaction and the power struggles in its aftermath.
Humiliation: The Catalyst for the Arab Revolt
Authors: DELKATESH MOHAMAD
Published: April 2011

The Great Arab Revolt of 2011 has moved swiftly from the peaceful overthrow of autocrats in the nation‐states of Tunisia and Egypt to brutal repression in the tribal societies of Libya, Syria, Bahrain and Yemen.

Meanwhile, the wired youth bulge of the Middle East that brought change is dissipating into an impotent diaspora while the organized interests of the old regimes and the once‐suppressed Islamists charge ahead to power. This section examines the revolt, the reaction and the power struggles in its aftermath.
America's Internet Freedom Agenda
Authors: MOROZOV EVGENY
Published: April 2011

The Great Arab Revolt of 2011 has moved swiftly from the peaceful overthrow of autocrats in the nation‐states of Tunisia and Egypt to brutal repression in the tribal societies of Libya, Syria, Bahrain and Yemen.

Meanwhile, the wired youth bulge of the Middle East that brought change is dissipating into an impotent diaspora while the organized interests of the old regimes and the once‐suppressed Islamists charge ahead to power. This section examines the revolt, the reaction and the power struggles in its aftermath.
Identification of Expressed Genes During Infection of Chinese Cabbage (Brassica rapa subsp. pekinensis) by Plasmodiophora brassicae
Authors: SUNDELIN THOMAS , JENSEN DAN F. , LÜBECK METTE
Published: April 2011

ABSTRACT. Plasmodiophora brassicae is an obligate, biotrophic pathogen causing the club‐root disease of crucifers. Despite its importance as a plant pathogen, little is known about P. brassicae at the molecular level as most of its life cycle takes place inside the plant host, and axenic culturing is impossible. Discovery of genes expressed during infection and gene organization are the first steps toward a better understanding of the pathogen–host interaction. Here, suppression subtractive hybridization was used to search for the P. brassicae genes expressed during plant infection. One‐hundred and forty ESTs were found of which 49% proved to be P. brassicae genes. Ten novel P. brassicae genes were identified, and the genomic sequences surrounding four of the ESTs were acquired using genome walking. Alignment of the ESTs and the genomic DNA sequences confirmed that P. brassicae genes are intron rich and that the introns are small. These results show that it is possible to discover new P. brassicae genes from a mixed pool of both plant and pathogen cDNA. The results also revealed that some of the P. brassicae genes expressed in Chinese cabbage (Brassica rapa subsp. pekinensis) were identical to the genes expressed in the infection of Arabidopsis plants, indicating that these genes play an important role in P. brassicae infection.
Evaluation of a nanometer roughness scale resorbable media‐processed surface: a study in dogs
Authors: Marin Charles , Granato Rodrigo , Bonfante Estevam A. , Suzuki Marcelo , Janal Malvin N. , Coelho Paulo G.
Published: April 2011

Objectives: This study compared the biomechanical fixation and bone‐to‐implant contact (BIC) of implants with different surfaces treatment (experimental – resorbable blasting media‐processed nanometer roughness scale surface, and control – dual acid‐etched) in a dog model.

Material and methods: Surface characterization was made in six implants by means of scanning electron microscopic imaging, atomic force microscopy to evaluate roughness parameters, and X‐ray photoelectron spectroscopy (XPS) for chemical assessment. The animal model comprised the bilateral placement of control (n=24) and experimental surface (n=24) implants along the proximal tibiae of six mongrel dogs, which remained in place for 2 or 4 weeks. Half of the specimens were biomechanically tested (torque), and the other half was subjected to histomorphologic/morphometric evaluation. BIC and resistance to failure measures were each evaluated as a function of time and surface treatment in a mixed model ANOVA.

Results: Surface texturing was significantly higher for the experimental compared with the control surface. The survey XPS spectra detected O, C, Al, and Ti at the control group, and Ca (∼0.2– 0.9%) and P (∼1.7– 4.1%) besides O, C, Al, and Ti at experimental surfaces. While no statistical difference in BIC was found between experimental and control surfaces or between 2 and 4 weeks in vivo, both longer time and use of experimental surface significantly increased resistance to failure.

Conclusions: The experimental surface resulted in enhanced biomechanical fixation but comparable BIC relative to control, suggesting higher bone mechanical properties around the experimental implants.

To cite this article: Marin C, Granato R, Bonfante EA, Suzuki M, Janal MN, Coelho PG. Evaluation of a nanometer roughness scale resorbable media‐processed surface: a study in dogs. Clin. Oral Impl. Res. 23, 2012; 119–124. doi: 10.1111/j.1600‐0501.2010.02155.x
Influence of two barrier membranes on staged guided bone regeneration and osseointegration of titanium implants in dogs: part 1. Augmentation using bone graft substitutes and autogenous bone
Authors: Schwarz Frank , Mihatovic Ilja , Golubovic Vladimir , Hegewald Andrea , Becker Jürgen
Published: April 2011

Objectives: To assess the influence of two barrier membranes and two bone graft substitutes mixed with autogenous bone (AB) on staged guided bone regeneration and osseointegration of titanium implants in dogs.

Materials and methods: Four saddle‐type defects each were prepared in the upper jaw of six fox hounds and randomly filled with a natural bone mineral (NBM)+AB and a biphasic calcium phosphate (SBC)+AB and allocated to either an in situ gelling polyethylene glycol (PEG) or a collagen membrane (CM). At 8 weeks, modSLA titanium implants were inserted and left to heal in a submerged position. At 8+2 weeks, dissected blocks were processed for histomorphometrical analysis (e.g., treated area [TA], bone‐to‐implant contact [BIC]).

Results: The mean TA values (mm2) and BIC values (%) tended to be higher in the PEG groups(TA: NBM+AB [10.4 ± 2.5]; SBC+AB [10.4 ± 5.8]/BIC: NBM+AB [86.4 ± 20.1]; SBC+AB [80.1 ± 21.5]) when compared with the corresponding CM groups (TA: NBM+AB [9.7 ± 4.8]; SBC+AB [7.8 ± 4.3]/BIC: NBM+AB [71.3 ± 20.8]; SBC+AB [72.4 ± 20.3]). A significant difference was observed for the mean TA values in the SBC+AB groups.

Conclusion: It was concluded that all augmentation procedures investigated supported bone regeneration and staged osseointegration of modSLA titanium implants. However, the application of PEG may be associated with increased TA values.

To cite this article: Schwarz F, Mihatovic I, Golubovic V, Hegewald A, Becker J. Influence of two barrier membranes on staged guided bone regeneration and osseointegration of titanium implants in dogs: part 1. Augmentation using bone graft substitutes and autogenous bone. Clin. Oral Impl. Res. 23, 2012; 83–89. doi: 10.1111/j.1600‐0501.2011.02187.x
Use of a titanium device in lateral sinus floor elevation: an experimental study in monkeys
Authors: Schweikert Michael , Botticelli Daniele , de Oliveira José Américo , Scala Alessandro , Salata Luiz A. , Lang Niklaus P.
Published: April 2011

Aim: To evaluate the effect of a space‐maintaining device fixed to the lateral wall of the maxillary sinus after the elevation of the sinus mucosa on bone filling of the sinus cavity.

Material and methods: Immediately after the elevation of the maxillary sinus Schneiderian membrane accomplished through lateral antrostomy in four monkeys, a titanium device was affixed to the lateral sinus wall protruding into the sinus cavity to maintain the mucosa elevated without the use of grafting material. The healing of the tissue around the implants was evaluated after 3 and 6 months. Ground sections were prepared and analyzed histologically.

Results: The void under the elevated sinus membrane, originally filled with the blood clot, was reduced after 3 as well as after 6 months of healing of about 56% and 40.5%, respectively. In seven out of eight cases, the devices had perforated the sinus mucosa. The formation of mineralized bone and bone marrow amounted to about 42% and 69% after 3 and 6 months, respectively. The connective tissue represented about 53% and 23% of the newly formed tissue after 3 and 6 months, respectively.

Conclusions: New bone formation was found below the devices. However, shrinkage of the newly formed tissue was observed both after 3 and 6 months of healing. Hence, the space‐maintaining function of the devices used in the present study has to be questioned.

To cite this article: Schweikert M, Botticelli D, de Oliveira JA, Scala A, Salata LA, Lang NP. Use of a titanium device in lateral sinus floor elevation: an experimental study in monkeys. Clin. Oral Impl. Res. 23, 2012; 100–105. doi: 10.1111/j.1600‐0501.2011.02200.x
Experimentally increased turbidity causes behavioural shifts in Lake Malawi cichlids
Authors: Gray Suzanne M. , Sabbah Shai , Hawryshyn Craig W.
Published: April 2011

Abstract –  The aquatic environment is being perturbed globally through increases in turbidity, which can have detrimental effects for the maintenance of fish diversity, especially in species dependent on visual cues for reproduction and species recognition. We performed a short‐term manipulation of the visual environment in Lake Malawi to test for an immediate behavioural response to increased turbidity in territorial rock‐dwelling cichlid fishes that use colourful visual cues to maintain territories near the substrate and attract mates. We found a significant movement of fish away from the substrate, with a concomitant shift from displaying territorial and courting behaviours to foraging behaviours, during the five minutes following the release of a turbidity plume over the area. This study is the first to test for and demonstrate an immediate behavioural response of a natural fish population to a short‐term increase in turbidity that might mimic the initial (i.e., immediate) stage of a run‐off event after rainfall in a deforested area.
Dietary plasticity of Arctic charr (Salvelinus alpinus) facilitates coexistence with competitively superior European whitefish (Coregonus lavaretus)
Authors: Eloranta Antti P. , Siwertsson Anna , Knudsen Rune , Amundsen Per‐Arne
Published: April 2011

Abstract – Habitat use and diet of Arctic charr (Salvelinus alpinus) coexisting with European whitefish (Coregonus lavaretus) and grayling (Thymallus thymallus) were studied in one deep and two relatively shallow subarctic lakes in northern Norway. Stomach content and stable isotope analyses revealed clear and temporally stable resource partitioning between the species in all three lakes. Arctic charr had a wide and flexible trophic niche and was the only piscivorous species. In contrast, whitefish and grayling had remarkably stable planktivorous and benthivorous niches, respectively. In the deepest lake, Arctic charr together with grayling mainly utilised littoral benthos, while piscivory was more prevalent in Arctic charr in the two shallower lakes. In one of the shallow lakes, whitefish was apparently relegated to the inferior profundal niche because of dominance of the littoral by grayling. Our results suggest that Arctic charr may not necessarily need an extensive profundal zone as a refuge, but can coexist with whitefish if a third competing fish species like grayling occurs in the littoral habitat or if profitable small prey fish are available. The study demonstrates that strong dietary plasticity of Arctic charr is instrumental in the observed coexistence with the commonly competitively superior whitefish.
Dynamics of Native β‐actin mRNA Transport in the Cytoplasm
Authors: Lifland Aaron W. , Zurla Chiara , Yu Joana , Santangelo Philip J.
Published: April 2011

Transport of messenger RNAs (mRNAs) in the cytoplasm is essential for localization to translation sites and for post‐transcriptional regulation. Utilizing single‐RNA sensitive probes and real‐time fluorescence microscopy, we accurately quantified the dynamics of native, non‐engineered, β‐actin mRNAs within the cytoplasm of epithelial cells and fibroblasts for the first time. Using single‐particle tracking and temporal analysis, we determined that native β‐actin mRNAs, under physiologic conditions, exhibit bursts of intermittent, processive motion on microtubules, interspersed between time periods of diffusive motion, characterized by non‐thermal enhanced diffusivity. When transport processes were perturbed via ATP depletion, temperature reduction, dynamitin overexpression and chemical inhibitors, processive motion was diminished or eliminated and diffusivity was reduced. These data support a model whereby processive, motor‐driven motion is responsible for long‐distance mRNA transport.
ESCRT Proteins and Cell Signalling
Authors: Wegner Catherine Sem , Rodahl Lina M. W. , Stenmark Harald
Published: April 2011

Subunits of the endosomal sorting complex required for transport (ESCRT) were identified as components of a molecular machinery that sorts ubiquitinated membrane proteins into the intraluminal vesicles (ILVs) of multivesicular endosomes (MVEs) for subsequent delivery to the lumen of lysosomes or related organelles. As many of the membrane proteins that undergo ESCRT‐mediated sorting are signalling receptors that are ubiquitinated in response to ligand binding, ESCRT subunits have been hypothesized to play a crucial role in attenuation of cell signalling by mediating ligand‐induced receptor degradation. Here we discuss this concept based on the examples from loss‐of‐function studies in model organisms and cell lines. The emerging picture is that ESCRTs are indeed involved in downregulation of receptor signalling pathways associated with cell survival, proliferation and polarity. In addition, the recent discovery of a positive role for the ESCRT pathway in Wnt signalling through sequestration of an inhibitory cytosolic component into MVEs illustrates that ESCRTs may also control signalling in ways that are independent of degradative receptor sorting.