bluuebunny/crossref_metadata_2025 huggingface dataset:
Migrant Organization and Hometown Impacts in Rural Mexico
Authors: FOX JONATHAN , BADA XOCHITL
Published: April 2008

The interaction between migration, development and rural democratization is not well understood. Exit is usually understood as an alternative to voice, but the Mexican experience with cross‐border social and civic action led by hometown associations suggests that exit can also be followed by voice. This article explores migrant impacts on hometown civic life, focusing on voice and bargaining over community development investments of collective remittances that are matched by government social funds. The most significant democratizing impacts include expatriate pressures on local governments for accountability and greater voice for outlying villages in municipal decision‐making.
From Covert to Overt: Everyday Peasant Politics in China and the Implications for Transnational Agrarian Movements
Authors: WALKER KATHY LE MONS
Published: April 2008

This contribution spotlights overt collective action as the form of everyday peasant politics in post‐socialist China. It first considers the interlinking in the post‐socialist period of global neoliberal capitalism and internal (so‐called) primitive accumulation by corrupt officials and eager entrepreneurs. Against this background it examines the collective protests of the last 20 years, focusing first on the issue of corrupt local power and then on land seizures. It argues that the emergence of sustained rural contention has been informed by China's socialist legacy as well as older peasant ideologies, and it has involved the coalescence of a shared class perspective among the poor and dispossessed. The final portion of the article considers the implications of these everyday peasant politics, especially land struggles, for transnational agrarian movements.
Where There Is No Movement: Local Resistance and the Potential for Solidarity
Authors: MALSEED KEVIN
Published: April 2008

In Burma, any attempt to form independent agrarian movements is violently suppressed, yet rural Karen villagers have developed and practise complex forms of resistance involving inter‐community action and solidarity across wide regions. These have been successful in weakening state control over land and livelihoods largely because their lack of formal organization makes them difficult to target. Though Karen village resistance has characteristics that resemble ‘movements’ as broadly defined and make it comparable to some existing agrarian movements, transnational movement coalitions have yet to actively engage with it. This contribution argues that transnational agrarian movements and local struggles could both benefit from active engagement, and explores the possibility and potential for such engagement in the Karen case.
Glutamate induces release of glutathione from cultured rat astrocytes – a possible neuroprotective mechanism?
Authors: Frade João , Pope Simon , Schmidt Maike , Dringen Ralf , Barbosa Rui , Pocock Jennifer , Laranjinha João , Heales Simon
Published: April 2008

Glutamate is the major excitatory amino acid of the mammalian brain but can be toxic to neurones if its extracellular levels are not tightly controlled. Astrocytes have a key role in the protection of neurones from glutamate toxicity, through regulation of extracellular glutamate levels via glutamate transporters and metabolic and antioxidant support. In this study, we report that cultures of rat astrocytes incubated with high extracellular glutamate (5 mM) exhibit a twofold increase in the extracellular concentration of the tripeptide antioxidant glutathione (GSH) over 4 h. Incubation with glutamate did not result in an increased release of lactate dehydrogenase, indicating that the rise in GSH was not because of membrane damage and leakage of intracellular pools. Glutamate‐induced increase in extracellular GSH was also independent of de novo GSH synthesis, activation of NMDA and non‐NMDA glutamate receptors or inhibition of extracellular GSH breakdown. Dose–response curves indicate that GSH release from rat astrocytes is significantly stimulated even at 0.1 mM glutamate. The ability of astrocytes to increase GSH release in the presence of extracellular glutamate could be an important neuroprotective mechanism enabling neurones to maintain levels of the key antioxidant, GSH, under conditions of glutamate toxicity.
Identification of multiple post‐translational modifications in the porcine brain specific p25α
Authors: Kleinnijenhuis Anne J. , Hedegaard Claus , Lundvig Ditte , Sundbye Sabrina , Issinger Olaf Georg , Jensen Ole Nørregaard , Jensen Poul Henning
Published: April 2008

P25α is a protein normally expressed in oligodendrocytes and subcellular relocalization of p25α occurs in multiple system atrophy, Parkinson’s disease and Lewy body dementia along with ectopic expression in neurons. Moreover, it accumulates in Lewy body inclusions with aggregated α‐synuclein and is a potent stimulator of α‐synuclein aggregation. P25α is a phosphoprotein and post‐translational modifications (PTMs) may play a role in its disease‐related abnormalities. To investigate the spectrum of PTMs on p25α we cloned porcine p25α and isolated the protein from porcine brain. Using several complementary tandem mass spectrometry techniques for peptide mass analysis and amino acid sequencing, a comprehensive analysis of the PTMs on porcine p25α was performed. It was found that porcine p25α is heavily modified with a variety of modifications: phosphorylation, di‐ and trimethylation, citrullination and a HexNAc group. The modifications are localized within p25α’s unfolded terminal domains and suggest that their functional states are regulated. This comprehensive mapping of p25α’s PTMs will form the basis for future functional studies and investigations of p25α’s potential role as a biomarker.
Leucine induces phosphorylation and activation of p70S6K in cortical neurons via the system L amino acid transporter
Authors: Ishizuka Yuta , Kakiya Naomasa , Nawa Hiroyuki , Takei Nobuyuki
Published: April 2008

p70S6 kinase is a multipotent kinase that phosphorylates substrates in response to extracellular stimuli. This kinase activity inhibits apoptosis, regulates cell size and controls translation. In the CNS, p70S6K also participates in synaptic plasticity. In this study, we report that leucine, a branched‐chain amino acid, induces phosphorylation and activation of p70S6 kinase in cortical neurons. Leucine also induces phosphorylation of S6 protein, a substrate of p70S6K. These effects of leucine are completely inhibited by rapamycin, consistent with mammalian target of rapamycin mediating p70S6 phosphorylation. Finally, we demonstrate that the action of leucine on cortical neurons is mediated by the system L amino acid transporter. Neurons express components of system L amino acid transporter LAT1, LAT2, and CD98. Leucine uptake and its effect on p70S6 kinase are both inhibited by a specific inhibitor of system L amino acid transporter. We propose that leucine plays important roles in regulating signaling by p70S6 kinase by acting as an intercellular communicator in the CNS.
THE INTERNATIONAL DIMENSIONS OF NEUROETHICS
Authors: LOMBERA SOFIA , ILLES JUDY
Published: April 2008

Neuroethics, in its modern form, investigates the impact of brain science in four basic dimensions: the self, social policy, practice and discourse. In this study, we analyzed a set of 461 peer‐reviewed articles with neuroethics content, published by authors from 32 countries. We analyzed the data for: (1) trends in the development of international neuroethics over time, and (2) how challenges at the intersection of ethics and neuroscience are viewed in countries that are considered developed by International Monetary Fund (IMF) standards, and in those that are developing. Our results demonstrate a steady increase in global participation in neuroethics from 1989 to 2005, characterized by an increase in numbers of articles published specifically on neuroethics, journals publishing these articles, and countries contributing to the literature. The focus from all countries was on the practice of brain science and the amelioration of neurological disease. Indicators of technology creation and diffusion in developing countries were specifically correlated with increases in publications concerning policy implications of brain science. Neuroethics is an international endeavor and, as such, should be sensitive to the impact that context has on acceptance and use of technological innovation.
Electron microscopy encounters with unusual thermophiles helps direct genomic analysis of Aciduliprofundum boonei
Authors: REYSENBACH A.‐L. , FLORES G. E.
Published: April 2008

Terry Beveridge's enthusiasm about the ingenuity of microorganisms has stimulated many new avenues of microbial research. One example where Terry's observations helped direct the scientific process was in the analysis of the draft genome of the thermoacidophilic archaeum, Aciduliprofundum boonei. This deep‐sea vent heterotroph ferments peptides as its primary metabolic pathway, using numerous enzymes encoding for proteolytic or peptidolytic activities. An almost complete modified Embden–Meyerhof–Parnas pathway operates in the gluconeogenic direction. Terry was particularly intrigued by the S‐layer and flagellum of A. boonei. Although only putative genes for the S‐layer protein could be identified, several genes encoding for glycosyl transferases were located in the draft genome that could glycosylate the S‐layer proteins and protect the proteins from the acidic environment. Furthermore, A. boonei possesses a unique organization to its flagellum genes and may represent a third organizational type within the Archaea.
Arterial stiffness, endothelial function and microcirculatory reactivity in healthy young males
Authors: Wright C. I. , Scholten H. J. , Schilder J. C. M. , Elsen B. M. , Hanselaar W. , Kroner C. I. , Draijer R. , Kastelein J. J. P. , Stok W. , Karemaker J. , De Groot E.
Published: April 2008

Large (C1) and small (C2) arterial stiffness has been suggested to parallel endothelial reactivity and has led researchers to suggest parameters of arterial stiffness may be alternative measures to brachial sonographic assessments of flow‐mediated dilatation (FMD). However, past studies comparing these measures can be criticized. In addition to %FMD responses, we recorded concurrent hyperaemic responses of the microcirculation and both were compared with C1 and C2. Twenty‐nine subjects 18–30 years of age were investigated. Radial blood pressure was recorded with a tonometer. Pulse waveform analysis was performed to calculate C1 and C2. These were compared with %FMD responses and responses of finger flux measured by laser Doppler fluxmetry (LDF); pulsatile finger volume measured by photoplethysmography (PPG); and palm skin temperature measured by infrared thermography (Tpalm) (i.e. microcirculatory responses). Responses were determined as % changes from control. We only found weak relationships between C1 and %FMD (r = 0·4, P = 0·04); C2 and %PPG (r = 0·38, P = 0·07); and C2 and %LDFdorsal (r = −0·38; P = 0·04). Responses of %FMD weakly parallel those of C1. Neither C2 nor C1 are viable indicators of endothelial or microcirculatory reactivity (i.e. hyperaemic or venous constriction) in healthy, resting young males. These findings refute the claims that C1 and C2 are substitute measures to sonographic assessments of brachial FMD.
Stimulant Induced Psychosis
Authors: Shibib Shatha , Chalhoub Nevyne
Published: April 2008

Background:  Stimulants are used as a first line option in the treatment of ADHD and are amongst the safest drugs used in children and adolescents. The potential for psychotic side effects are well known, but reported as rare.

Method:  We are reporting four cases of stimulant induced psychosis which presented over a 2 year period in a small community CAMHS setting.

Results:  Our findings suggest that stimulant induced psychosis occurs. The symptoms in the early stages of the psychotic episode mimicked ADHD. Long acting preparations appeared to be a contributory factor to the development of psychotic side effects. Rechallenge with stimulant medication is described.

Conclusion:  Psychosis is an important, unpredictable side effect of stimulant medication. Symptoms resolve with discontinuation of treatment. Remergence of ADHD symptoms are rapid and rechallenge is often indicated. It would be advisable for all professionals involved in the care and treatment of patients with ADHD to receive mental health training to aid the early recognition and appropriate management of such side effects.
Influence of Representation Targets on the Total Area of Conservation‐Area Networks
Authors: JUSTUS JAMES , FULLER TREVON , SARKAR SAHOTRA
Published: April 2008

Abstract:  Systematic conservation planning typically requires specification of quantitative representation targets for biodiversity surrogates such as species, vegetation types, and environmental parameters. Targets are usually specified either as the minimum total area in a conservation‐area network in which a surrogate must be present or as the proportion of a surrogate's existing spatial distribution required to be in the network. Because the biological basis for setting targets is often unclear, a better understanding of how targets affect selection of conservation areas is needed. We studied how the total area of conservation‐area networks depends on percentage targets ranging from 5% to 95%. We analyzed 12 data sets of different surrogate distributions from 5 regions: Korea, Mexico, Québec, Queensland, and West Virginia. To assess the effect of spatial resolution on the target‐area relationship, we also analyzed each data set at 7 spatial resolutions ranging from 0.01°× 0.01° to 0.10°× 0.10°. Most of the data sets showed a linear relationship between representation targets and total area of conservation‐area networks that was invariant across changes in spatial resolution. The slope of this relationship indicated how total area increased with target level, and our results suggest that greater surrogate representation requires significantly more area. One data set exhibited a highly nonlinear relationship. The results for this data set suggest a new method for setting targets on the basis of the functional form of target‐area relationships. In particular, the method shows how the target‐area relationship can provide a rationale for setting targets solely on the basis of distributional information about surrogates.
Household Location Choices: Implications for Biodiversity Conservation
Authors: PETERSON M. NILS , CHEN XIAODONG , LIU JIANGUO
Published: April 2008

Abstract:  Successful conservation efforts require understanding human behaviors that directly affect biodiversity. Choice of household location represents an observable behavior that has direct effects on biodiversity conservation, but no one has examined the sociocultural predictors of this choice relative to its environmental impacts. We conducted a case study of the Teton Valley of Idaho and Wyoming (U.S.A.) that (1) explored relationships between sociodemographic variables, environmental attitudes, and the environmental impact of household location choices, (2) assessed the potential for small household sizes in natural areas to multiply the environmental impacts of household location decisions, and (3) evaluated how length of residency predicted the environmental attitudes of people living in natural areas. We collected sociodemographic data, spatial coordinates, and land‐cover information in a survey of 416 households drawn from a random sample of Teton Valley residents (95% compliance rate). Immigrants (respondents not born in the study area) with the lowest education levels and least environmentally oriented attitudes lived in previously established residential areas in disproportionately high numbers, and older and more educated immigrants with the most environmentally oriented attitudes lived in natural areas in disproportionately high numbers. Income was not a significant predictor of household location decisions. Those living in natural areas had more environmental impact per person because of the location and because small households (<3 people/household) were 4 times as likely in natural areas as large households. Longer residency in natural areas predicted less environmentally oriented attitudes, suggesting that living in natural areas does not foster more concern for nature. Because populaces are rapidly aging, growing more educated, and potentially growing more environmentally oriented, these patterns are troubling for biodiversity conservation. Our results demonstrate a need for environmentalists to make household location decisions that reflect their environmental attitudes and future research to address how interactions between education level, environmental attitudes, population aging, and household location choices influence biodiversity conservation.
Genetic susceptibility to Keloid scarring: SMAD gene SNP frequencies in Afro‐Caribbeans
Authors: Brown Jason J. , Ollier William , Arscott Guyan , Ke Xiayi , Lamb Janine , Day Philip , Bayat Ardeshir
Published: April 2008

Abstract:  Keloid disease (KD) is a fibroproliferative dermal tumour of unknown aetiology. The increased familial clustering in KD, its increased prevalence in certain races and increased concordance in identical twins suggest a strong genetic predisposition to keloid formation. The highest incidence of keloids is found in the black population, where it has been estimated around 4–6% and up to 16% in random samples of black Africans. SMAD genes 3, 6 and 7 were investigated as candidate genes in Jamaican patients with keloid scars (n = 183) and a matched control population (n = 121) because of their previously reported involvement in fibrotic disorders and to determine if they were associated with keloid disease susceptibility. Thirty Five SNPs across these genes were genotyped using Time‐of‐Flight Mass Spectrometry (MALDI‐TOF MS) and iPLEX assay. Linkage disequilibrium (LD) was established between several of the SNPs investigated. In the Jamaican population, the SMAD SNPs investigated for this study were not strongly associated with increased risk of developing KD. Identification of genetic markers in candidate genes such as the SMAD family may be of significant importance in diagnosis, prognosis and development of new therapies in the management of keloid scarring.
Multiple erythema migrans – manifestation of systemic cutaneous borreliosis
Authors: Egberts Friederike , Möller Maike , Proksch Erhardt , Schwarz Thomas
Published: April 2008

Erythema migrans is the clinical hallmark lesion of a stage I infection with Borrelia burgdorferi. Multifocal lesions are rarely observed in Europe and thus may be missed, in particular when the typical clinical appearance of the pronounced advancing margin is missing.We present three patients with such a clinical appearance which caused differential diagnostic problems. Multiple erythema migrans represent an early stage of systemic infection. Thus early diagnosis and rapid initiation of therapy are warranted.
Recommendations for the use of rituximab (anti‐CD20 antibody) in the treatment of autoimmune bullous skin diseases§
Authors: Hertl Michael , Zillikens Detlef , Borradori Luca , Bruckner‐Tuderman Leena , Burckhard Harald , Eming Rüdiger , Engert Andreas , Goebeler Matthias , Hofmann Silke , Hunzelmann Nicolas , Karlhofer Franz , Kautz Ocko , Lippert Undine , Niedermeier Andrea , Nitschke Martin , Pfütze Martin , Reiser Marcel , Rose Christian , Schmidt Enno , Shimanovich Iakov , Sticherling Michael , Wolff‐Franke Sonja
Published: April 2008

Autoimmune bullous skin disorders are induced by autoantibodies against distinct adhesion complexes of the epidermal and dermal‐epidermal junction. Since most of these disorders are characterized by a severe, potentially lethal course,they require long‐term immunosuppressive treatment to reduce the de novo synthesis of pathogenic autoantibodies by B lymphocytes. Rituximab, a chimeric monoclonal antibody against CD20 on B lymphocytes, has shown promise in several case reports or cohort studies in the treatment of paraneo‐plastic pemphigus,refractory cases of pemphigus vulgaris and foliaceus and in other autoimmune bullous disorders.Treatment with rituximab leads to depletion of pathogenic B‐cells which may last up to 12 months resulting in a reduction of plasma cells secreting pathogenic autoantibodies.Rituximab is usually administered in an adjuvant setting at a dose of 375 mg/m2 i.v.in weekly intervals for four consecutive weeks in addition to the standard immunosuppressive treatment.The present consensus statement of German‐speaking derma‐tologists,rheumatologists and oncologists summarizes and evaluates the current evidence for the use and mode of application of rituximab in autoimmune bullous skin disorders.
High‐dose intravenous corticosteroid pulse therapy in alopecia areata: Own experience compared with the literature
Authors: Luggen Peter , Hunziker Thomas
Published: April 2008

Background: Seven prospective studies including 193 patients have been published on high‐dose intravenous corticosteroid pulse therapy in alopecia areata (AA).We compare these data with a retrospective analysis of our own consecutive patients.

Patients and Methods: Between 1998 and 2002,25 patients with severe AA were treated at the Department of Dermatology, University of Bern, with infusions of 500 mg methylprednisolone on 3 consecutive days.In addition to the inpatient records, in 2004 all patients were followed up by a questionnaire.

Results: Four of 10 patients with multifocal AA and 3 of 9 patients with ophiasis‐type AA had full re‐growth of hair, whereas all 6 patients with AA totalis/universalis failed to respond.

Conclusion: Intravenous corticosteroid pulse therapy may be helpful in the treatment of multifocal and ophiasis‐type AA.Patients with an initial episode of short duration have better chances for success.
Current therapeutic options of chronic leg ulcers
Authors: Renner Regina , Simon Jan C.
Published: April 2008

Wound treatment is continually becoming more complex and difficult. In the following review, we focus on the different options of wound debridement, stimulation of granulation tissue, different wound dressings, and therapeutic strategies in hard‐to‐heal‐wounds. We also present some future treatment options for chronic wounds.
Keratoacanthoma with perineural invasion: An indicator for aggressive behavior?
Authors: Basoglu Yasmin , Metze Dieter , Nashan Dorothee , Ständer Sonja
Published: April 2008

Neurotropic invasion of keratoacanthoma (KA) is rare and can easily be missed histologically. A 36‐year‐old woman developed a KA on the upper lip four weeks after CO2 laser skin resurfacing; it showed microscopic evidence of perineural invasion. Despite repeated treatment with intralesional methotrexate, the KA recurred after 6 months. She was then treated with ionizing radiation (56 Gy) and has been tumor‐free for more than 3 years.

Immunohistochemistry showed decreased expression of desmoglein 1 as it is seen in squamous cell carcinomas. In most cases not much importance is attached to perineural invasion which is frequently seen in KA because of the high rate of spontaneous regression. Our case suggests that perineural invasion may be an indicator for aggressive growth of head‐and‐neck KAs so that histologically‐controlled excision is recommended.
Hypoxia induces expression of a GPI‐anchorless splice variant of the prion protein
Authors: Kikuchi Yutaka , Kakeya Tomoshi , Nakajima Osamu , Sakai Ayako , Ikeda Kikuko , Yamaguchi Naoto , Yamazaki Takeshi , Tanamoto Ken‐ichi , Matsuda Haruo , Sawada Jun‐ichi , Takatori Kosuke
Published: April 2008

The human prion protein (PrP) is a glycoprotein with a glycosylphosphatidylinositol (GPI) anchor at its C‐terminus. Here we report alternative splicing within exon 2 of the PrP gene (PRNP) in the human glioblastoma cell line T98G. The open reading frame of the alternatively spliced mRNA lacked the GPI anchor signal sequence and encoded a 230 amino acid polypeptide. Its product, GPI‐anchorless PrP (GPI− PrPSV), was unglycosylated and soluble in non‐ionic detergent, and was found in the cytosolic fraction. We also detected low levels of alternatively spliced mRNA in human brain and non‐neuronal tissues. When long‐term passaged T98G cells were placed in a low‐oxygen environment, alternatively spliced mRNA expression increased and expression of normally spliced PrP mRNA decreased. These findings imply that oxygen tension regulates GPI− PrPSV expression in T98G cells.
Aldo‐keto reductase from Helicobacter pylori– role in adaptation to growth at acid pH
Authors: Cornally Denise , Mee Blanaid , MacDonaill Ciarán , Tipton Keith F. , Kelleher Dermot , Windle Henry J. , Henehan Gary T. M.
Published: April 2008

Pyridine‐linked oxidoreductase enzymes of Helicobacter pylori have been implicated in the pathogenesis of gastric disease. Previous studies in this laboratory examined a cinnamyl alcohol dehydrogenase that was capable of detoxifying a range of aromatic aldehydes. In the present work, we have extended these studies to identify and characterize an aldoketo reductase (AKR) enzyme present in H. pylori. The gene encoding this AKR was identified in the sequenced strain of H. pylori, 26695. The gene, referred to as HpAKR, was cloned and expressed in Escherichia coli as a His‐tag fusion protein, and purified using nickel chelate chromatography. The gene product (HpAKR) has been assigned to the AKR13C1 family, although it differs in specificity from the two other known members of this family. The enzyme is a monomer with a molecular mass of approximately 39 kDa on SDS/PAGE. It reduces a range of aromatic aldehyde substrates with high catalytic efficiency, and exhibits dual cofactor specificity for both NADPH and NADH. HpAKR can function over a broad pH range (pH 4–9), and has a pH optimum of 5.5. It is inhibited by sodium valproate. Its substrate specificity complements that of the cinnamyl alcohol dehydrogenase activity in H. pylori, giving the organism the capacity to reduce a wide range of aldehydes. Generation of an HpAKR isogenic mutant of H. pylori demonstrated that HpAKR is required for growth under acidic conditions, suggesting an important role for this enzyme in adaptation to growth in the gastric mucosa. This AKR is a member of a hitherto little‐studied class.
Microstructured and Electro‐Assisted High‐Temperature Wettability of MgO in Contact with a Silicate Slag‐Based on Fayalite
Authors: Aneziris Christos G. , Hampel Michael
Published: April 2008

In this work, MgO samples have been microstructured by laser treatment and surfaces with a controlled stripe design have been manufactured. Sessile drop wetting measurements were performed in a special heating microscope by determining horizontal contact angles as well as contact angles as a function of surface inclination angles. In a further step, voltage was applied to ground MgO surfaces and the wetting behavior was registered as a function of the voltage level. Activation energy analysis was conducted for all the experiments.
Effect of CMAS Infiltration on Radiative Transport Through an EB‐PVD Thermal Barrier Coating
Authors: Li Li , Clarke David R.
Published: April 2008

One of the adverse effects of sand ingestion in gas turbines is that the thermal barrier coatings on the blades and vanes can be infiltrated at high temperatures by molten calcium–magnesium–aluminum–silicate (CMAS) and cause premature failure of the coating. To investigate the effect of CMAS penetration, the optical properties of a synthetic glass representative of CMAS are reported from 500 nm to 2.5 μm. Results are then presented to show that silicate infiltration of an electron beam‐deposited TBC can increase radiative transport through the coating. The results are qualitatively consistent with a simple optical scattering model for radiative transport through a porous coating.
Development of Agile Titania Sensors Via High‐Temperature Reductive Etching Process (HiTREP©): I. Structural Reorganization
Authors: Azad Abdul‐Majeed , Dolan Shawn , Akbar Sheikh A.
Published: April 2008

High selectivity, enhanced sensitivity, short response times and long shelf‐life are much sought‐after features in solid‐state chemical sensors for the detection and metering of gas(es) of interest. Because the sensing mechanism of semiconducting oxides is invariably surface dominated, benign microscopic features are desirable to realize a useful sensing material. In principle, such morphological features could be incorporated in a number of semiconducting oxides by employing a technique based on thermodynamic consideration of the metal/metal oxide coexistence. By dynamically modulating the equilibrium oxygen partial pressure across the metal/metal oxide proximity line, renewed formulation and growth of an oxide surface on an atomic/submolecular level with exotic morphological features under conditions of oxygen “deprivation” or “enrichment” has been achieved practically in a number of potential ceramic sensor systems. In the case of oxides that are not amenable to such classical oxygen partial pressure modulation, a novel high‐temperature reductive etching process (HiTREP©) could be exploited to recreate the smart nanofeatures to impart the desired accentuation effect. This surface modification method was applied to a new commercially available aqueous plasma electro‐deposited (PED) titania thick film, and the microscopic results of this strategy are presented.
Big Fish are the Best: Seed Dispersal of Bactris glaucescens by the Pacu Fish (Piaractus mesopotamicus) in the Pantanal, Brazil
Authors: Galetti Mauro , Donatti Camila I. , Pizo Marco Aurélio , Giacomini Henrique C.
Published: April 2008

We studied the potential role as seed disperser of the pacu fish (Piaractus mesopotamicus, Characidae) in the Pantanal of Brazil. The most important food item in the diet of the pacu in the wet season was fruits of the palm Bactris glaucescens found in the guts of 73 percent of all fishes collected (N= 70). We found a positive relationship between fish length, weight, and gape size and the number of intact seeds in their gut. Therefore, large pacus are especially important in dispersing B. glaucescens seeds within the studied system. Since the best seed dispersers are the largest fishes, which are preferred by commercial fisheries, we predict that the ongoing over fishing in freshwater ecosystems will have major impacts on the dispersal system of fish‐dependent plants. We suggest that it is paramount to change the attitudes in fisheries management of fruit‐eating fishes and urgent to evaluate the impact of fishing on forest regeneration.
Seedling Traits Determine Drought Tolerance of Tropical Tree Species
Authors: Poorter Lourens , Markesteijn Lars
Published: April 2008

Water availability is the most important factor determining tree species distribution in the tropics, but the underlying mechanisms are still not clear. In this study, we compared functional traits of 38 tropical tree species from dry and moist forest, and quantified their ability to survive drought in a dry‐down experiment in which wilting and survival were monitored. We evaluated how seedling traits affect drought survival, and how drought survival determines species distribution along the rainfall gradient. Dry forest species tended to have compound leaves, high stem dry matter content (stem dry mass/fresh mass), and low leaf area ratio, suggesting that reduction of transpiration and avoidance of xylem cavitation are important for their success. Three functional groups were identified based on the seedling traits: (1) drought avoiders with a deciduous leaf habitat and taproots; (2) drought resisters with tough tissues (i.e., a high dry matter content); and (3) light‐demanding moist forest species with a large belowground foraging capacity. Dry forest species had a longer drought survival time (62 d) than moist forest species (25 d). Deciduousness explained 69 percent of interspecific variation in drought survival. Among evergreen species, stem density explained 20 percent of the drought survival. Drought survival was not related to species distribution along the rainfall gradient, because it was mainly determined by deciduousness, and species with deciduous seedlings are found in both dry and moist forests. Among evergreen species, drought survival explained 28 percent of the variation in species position along the rainfall gradient. This suggests that, apart from drought tolerance, other factors such as history, dispersal limitation, shade tolerance, and fire shape species distribution patterns along the rainfall gradient.
Patterns of Land Cover Change in and Around Madidi National Park, Bolivia
Authors: Forrest Jessica L. , Sanderson Eric W. , Wallace Robert , Lazzo Teddy Marcelo Siles , Cerveró Luis Humberto Gómez , Coppolillo Peter
Published: April 2008

This study examines how human land uses and biophysical factors serve as predictors of land cover change in and around Madidi National Park in Bolivia. The Greater Madidi Landscape ranges over an elevational gradient from < 200 m in the Amazon basin to 6000 m in the high Andes, contains more than ten major ecosystem types, and several protected areas and sustainable use zones. In this study, Landsat Thematic Mapper satellite images collected over the study area at the beginning of the 1990s and then the 2000s were classified according to broad land cover types. Below elevations of 3000 m, the landscape experienced equal rates of deforestation and secondary forest increases of approximately 0.63 percent annually, resulting in no significant net change. Below elevations of 1000 m, however, we found an annual net loss in forest cover of 0.11 percent. Across the landscape, land cover change was most likely to occur near areas previously deforested, near roads and population centers, and at low elevations. We found net deforestation rates to be inversely related to strength of natural resource protection laws in protected areas and other jurisdictions. Results suggest little net change for the landscape as a whole, but that local scale changes may be significant, particularly near roads. Management policies favorable for biodiversity conservation in this landscape should limit the building of new roads and immigration to biologically sensitive areas and continue to support protected areas, which are achieving a positive result for forest conservation.
Allometric Models for Predicting Aboveground Biomass in Two Widespread Woody Plants in Hawaii
Authors: Litton Creighton M. , Boone Kauffman J.
Published: April 2008

Allometric models are important for quantifying biomass and carbon storage in terrestrial ecosystems. Generalized allometry exists for tropical trees, but species‐ and site‐specific models are more accurate. We developed species‐specific models to predict aboveground biomass in two of the most ubiquitous natives in Hawaiian forests and shrublands, Metrosideros polymorpha and Dodonaea viscosa. The utility of the M. polymorpha allometry for predicting biomass across a range of sites was explored by comparing size structure (diameter at breast height vs. tree height) of the trees used to develop the models against trees from four M. polymorpha‐dominated forests along a precipitation gradient (1630–2380 mm). We also compared individual tree biomass estimated with the M. polymorpha model against existing generalized equations, and the D. viscosa model with an existing species‐specific model. Our models were highly significant and displayed minimal bias. Metrosideros polymorpha size structures from the three highest precipitation sites fell well within the 95% confidence intervals for the harvested trees, indicating that the models are applicable at these sites. However, size structure in the area with the lowest precipitation differed from those in the higher rainfall sites, emphasizing that care should be taken in applying the models too widely. Existing generalized allometry differed from the M. polymorpha model by up to 88 percent, particularly at the extremes of the data range examined, underestimating biomass in small trees and overestimating in large trees. The existing D. viscosa model underestimated biomass across all sizes by a mean of 43 percent compared to our model. The species‐specific models presented here should enable more accurate estimates of biomass and carbon sequestration in Hawaiian forests and shrublands.
Leaffall Phenology in a Subtropical Wet Forest in Puerto Rico: From Species to Community Patterns
Authors: Zalamea Marcela , González Grizelle
Published: April 2008

Leaffall phenology is an important periodical event in forests, contributing to mobilization of organic matter from primary producers to soil. For seasonal forests, leaffall periodicity has been related to rainfall regime and dry season length. In weakly seasonal forests, where there is no marked dry season, other climatic factors could trigger leaf shed. In this study, we aimed to determine if other climatic variables (wind speed, solar radiation, photosynthetic photon flux density [PPFD], day length, temperature, and relative humidity) could be better correlated with patterns of litter and leaffall in a weakly seasonal subtropical wet forest in Puerto Rico. Leaffall patterns were correlated mainly with solar radiation, PPFD, day length, and temperature; and secondarily with rainfall. Two main peaks of leaffall were observed: April–June and August–September, coinciding with the periods of major solar radiation at this latitude. Community leaffall patterns were the result of overlapping peaks of individual species. Of the 32 species analyzed, 21 showed phenological patterns, either unimodal (16 species), bimodal (three species), or multimodal (two species). Lianas also presented leaffall seasonality, suggesting that they are subject to the same constraints and triggering factors affecting trees. In addition to solar radiation as a main determinant of leaffall timing in tropical forests, our findings highlight the importance of interannual variation and asynchrony, suggesting that leaffall is the result of a complex interaction between environmental and physiological factors.
Altered Adhesive Structures and Their Relation to RhoGTPase Activation in Merlin‐Deficient Schwannoma
Authors: Flaiz Christine , Ammoun Sylwia , Biebl Anja , Hanemann C. Oliver
Published: April 2008

Schwannomas are Schwann cell tumors of the nervous system that occur spontaneously and in patients with neurofibromatosis 2 (NF2) and lack the tumor suppressor merlin. Merlin is known to bind paxillin, beta1 integrin and focal adhesion kinase, members of focal contacts, multi‐protein complexes that mediate cell adhesion to the extracellular matrix. Moreover, merlin‐deficient Schwannomas show pathological adhesion to the extracellular matrix making the characterization of focal contacts indispensable. Using our Schwannoma in vitro model of human primary Schwann and Schwannoma cells, we here show that Schwannoma cells display an increased number of mature and stable focal contacts. In addition to an involvement of RhoA signaling via the Rho kinase ROCK, Rac1 plays a significant role in the pathological adhesion of Schwannoma cells. The Rac1 guanine exchange factor— beta‐Pix, localizes to focal contacts in human primary Schwannoma cells, and we show that part of the Rac1 activation, an effect of merlin‐deficiency, occurs at the level of focal contacts in human primary Schwannoma cells. Our results help explaining the pathological adhesion of Schwannoma cells, further strengthen the importance of RhoGTPase signaling in Schwannoma development, and suggest that merlin's role in tumor suppression is linked to focal contacts.
Parametric and Nonparametric Regression in the Presence of Endogenous Control Variables
Authors: Frölich Markus
Published: April 2008

The aim of this paper is to convey to a wider audience of applied statisticians that nonparametric (matching) estimation methods can be a very convenient tool to overcome problems with endogenous control variables. In empirical research one is often interested in the causal effect of a variable X on some outcome variable Y. With observational data, i.e. in the absence of random assignment, the correlation between X and Y generally does not reflect the treatment effect but is confounded by differences in observed and unobserved characteristics. Econometricians often use two different approaches to overcome this problem of confounding by other characteristics. First, controlling for observed characteristics, often referred to as selection on observables, or instrumental variables regression, usually with additional control variables. Instrumental variables estimation is probably the most important estimator in applied work. In many applications, these control variables are themselves correlated with the error term, making ordinary least squares and two‐stage least squares inconsistent. The usual solution is to search for additional instrumental variables for these endogenous control variables, which is often difficult. We argue that nonparametric methods help to reduce the number of instruments needed. In fact, we need only one instrument whereas with conventional approaches one may need two, three or even more instruments for consistency. Nonparametric matching estimators permit

consistent estimation without the need for (additional) instrumental variables and permit arbitrary functional forms and treatment effect heterogeneity.
Play Theory, Playing, and Culture
Authors: Masters Patricia Anne
Published: April 2008

This article focuses on theoretical approaches to play and their application to play communities. It explores the work of pioneers in the study of this important interactional form: Johan Huizinga and Roger Caillois. In addition, the seminal work of Mihaly Csikszentmihalyi on the play experience and its seductive qualities for individuals is discussed. Briefly introduced is the recent work of Brian Sutton‐Smith who proposed that each discipline develops a specific rhetoric in studying play and identifies the rhetorics typically employed by scholars in the social sciences and the humanities. This article provides examples of approaches to analyzing the functional outcomes of cultural performances, including parades, and proposes broadening the scope of research to include not only the outcomes of play but also the experience of playing, thus illuminating our understanding of the strong bonds that are formed through communal play.
A GROWTH MODEL FOR SOUTH AFRICA
Authors: Rattsø Jørn , Stokke Hildegunn E.
Published: April 2008

We examine the South African growth experience during 1960‐2005 using an intertemporal growth model. The model combines old growth theory investment dynamics and new growth theory endogenous productivity growth. The consumption and investment decisions are intertemporal and assume open capital markets. Structural change is captured by separating the traded and nontraded sectors, and sectoral productivity growth is determined in a barriers‐to‐growth framework. Calibration of the model shows how the growth experience combines neoclassical convergence, technology spillovers with barriers and productivity‐investment interaction. Counterfactual analysis shows the growth costs of sanctions and protectionism. The suggested model is an alternative to existing growth modelling in South Africa, in which investments are short‐sighted and productivity growth is imposed exogenously.
INFLATION TARGETING AND THE FISHER EFFECT IN SOUTH AFRICA: AN EMPIRICAL INVESTIGATION
Authors: Mitchell‐innes H.a. , Aziakpono M.j. , Faure A.p.
Published: April 2008

The paper analyses the relationship between expected inflation and nominal interest rates during a period of inflation targeting in South Africa, i.e. from 2000 to 2005. Specifically, it investigates the Fisher hypothesis that nominal interest rates move one‐to‐one with expected inflation, leaving the real interest rate unaffected. The analysis distinguishes between a short‐run Fisher effect and a long‐run Fisher effect. Using cointegration and error correction models (for monthly data for the period April 2000 to July 2005), it was found that the short‐run Fisher hypothesis did not hold during the relevant period under the inflation targeting monetary policy framework in South Africa. This is attributed to a combination of the South African Reserve Bank's (SARB) control over short‐term interest rates and the effects of the monetary transmission mechanism. The long‐run Fisher hypothesis could not be confirmed in its strictest form: while changes in inflation expectations move in the same direction as the nominal long‐term interest rate. This suggests that monetary policy has an influence on the real long‐term interest rate, which has positive implications for general economic activity, thus confirming the credibility of the inflation targeting framework.
ESTIMATING SARB'S POLICY REACTION RULE
Authors: Ortiz Alberto , Sturzenegger Federico
Published: April 2008

This paper uses a Dynamic Stochastic General Equilibrium (DSGE) model to estimate the South African Reserve Bank's (SARB) policy reaction rule. We find that the SARB has a stable rule very much in line with those estimated for Canada, UK, Australia and New Zealand. Relative to other emerging economies the policy reaction function of the SARB appears to be much more stable with a consistent anti inflation bias, a somewhat larger weight on output and a very low weight on the exchange rate.
AFTER MUGABE GOES – THE ECONOMIC AND POLITICAL RECONSTRUCTION OF ZIMBABWE
Authors: Parsons Rwk
Published: April 2008

This Presidential address briefly outlines the developments in Zimbabwe since independence in 1980 leading up to the current political and economic crisis. The Zimbabwean situation is assessed within the conceptual framework of patrimonialism and predatory states. The origins of the Zimbabwean crisis are then analysed in their economic and political context leading to an eventual “fragile” or “failed” state. Evaluation of the crisis suggests that institutional damage has proceeded to the point at which only large scale economic and political reconstruction offers sustainable long term solutions, irrespective of when President Mugabe leaves office. The address concludes with an examination of the regional implications for Southern African Development Community – as well as the role of the global community – and outlines some of the core components of any reconstruction process‐to‐be in Zimbabwe.
LONG‐RUN M3 DEMAND IN SOUTH AFRICA: A COINTEGRATED VAR MODEL
Authors: Todani K.r.
Published: April 2008

This paper presents a system cointegration analysis of a long‐run demand for money (measured in terms of M3) in South Africa. In particular, the paper estimates a cointegrated vector autoregression model, consisting of real money, income and the opportunity cost of holding money. Using a variety of theory consistent identification schemes, the money demand function is identified along with other two cointegrating relations, namely, an IS‐type relationship and a relationship relating inflation to the spread between long‐ and short‐term interest rates. The model shows that of the variables used, only income and real money are error‐correcting to the money demand relation. The money demand relation is found to be relatively stable over the sample period, when short‐run fluctuations are corrected for. The model further shows that the long‐run link between money and inflation is rather weak.
THE IMPLICATIONS OF OECD GROWTH FOR SOUTH AFRICAN EXPORTS
Authors: Rangasamy L. , Brick K.
Published: April 2008

This paper examines the role of OECD growth on South African exports using a vector error correction model. In the long run both OECD growth and the real effective exchange rate were found to influence South Africa's export performance, while in the short run, the real effective exchange rate was found to be an important driver of export growth. The policy implications that emerge from the study underscore the importance of fully exploiting current trading relationships, diversifying South African export destinations and enhancing competitiveness.