bluuebunny/crossref_metadata_2025 huggingface dataset:
Evidence for a dual function of EphB4 as tumor promoter and suppressor regulated by the absence or presence of the ephrin‐B2 ligand
Authors: Rutkowski Raphael , Mertens‐Walker Inga , Lisle Jessica E. , Herington Adrian C. , Stephenson Sally‐Anne
Published: December 2011

Overexpression of the receptor tyrosine kinase EphB4 is common in epithelial cancers and linked to tumor progression by promoting angiogenesis, increasing survival and facilitating invasion and migration. However, other studies have reported loss of EphB4 suggesting a tumor suppressor function in some cancers. These opposing roles may be regulated by (i) the presence of the primary ligand ephrin‐B2 that regulates pathways involved in tumor suppression or (ii) the absence of ephrin‐B2 that allows EphB4 signaling via ligand‐independent pathways that contribute to tumor promotion. To explore this theory, EphB4 was overexpressed in the prostate cancer cell line 22Rv1 and the mammary epithelial cell line MCF‐10A. Overexpressed EphB4 localized to lipid‐rich regions of the plasma membrane and confirmed to be ligand‐responsive as demonstrated by increased phosphorylation of ERK1/2 and internalization. EphB4 overexpressing cells demonstrated enhanced anchorage‐independent growth, migration and invasion, all characteristics associated with an aggressive phenotype, and therefore supporting the hypothesis that overexpressed EphB4 facilitates tumor promotion. Importantly, these effects were reversed in the presence of ephrin‐B2 which led to a reduction in EphB4 protein levels, demonstrating that ligand‐dependent signaling is tumor suppressive. Furthermore, extended ligand stimulation caused a significant decrease in proliferation that correlated with a rise in caspase‐3/7 and ‐8 activities. Together, these results demonstrate that overexpression of EphB4 confers a transformed phenotype in the case of MCF‐10A cells and an increased metastatic phenotype in the case of 22Rv1 cancer cells and that both phenotypes can be restrained by stimulation with ephrin‐B2, in part by reducing EphB4 levels.
Effects of four types of hydroxyapatite nanoparticles with different nanocrystal morphologies and sizes on apoptosis in rat osteoblasts
Authors: Xu Zhengli , Liu Changsheng , Wei Jie , Sun Jiao
Published: December 2011

Hydroxyapatite nanoparticles (nano‐HAP) have been reported to cause inflammatory reactions. Here, we aimed to compare the effects of four types of nano‐HAP with different nanocrystal morphologies (short rod‐like, long rod‐like, spherical or needle‐shaped crystals) and sizes (10–20, 10–30 or 20–40 nm) on growth inhibition and apoptosis in primary cultured rat osteoblasts. The osteoblasts was treated with the four types of nano‐HAP at various concentrations (20, 40, 60, 80 or 100 mg l−1). The nano‐HAP specific surface area was detected using the Brunauer, Emmet and Teller method. The cell growth rate was detected using the 3‐(4,5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyltetrazolium bromide assay; apoptotic alterations and the level of reactive oxygen species in osteoblasts were measured using flow cytometry; and the amounts of apoptotic p53 and cytochrome c proteins were measured using western blotting. We observed that all four types of nano‐HAP inhibited the growth of osteoblasts in a dose‐dependent manner. These nano‐HAP significantly induced apoptosis in osteoblasts. Nano‐HAP with smaller specific surface areas induced lower apoptosis rates. The needle‐shaped and the short rod‐like particles induced greater cellular injury than the spherical and long rod‐like particles, respectively. The increased apoptosis rates were accompanied by increased p53 and cytochrome c expression. These findings indicate that nano‐HAP inhibit the activity of osteoblasts and also induce the apoptosis of osteoblasts in vitro. These findings also suggest that the nano‐HAP‐induced apoptotic pathway is mediated by a mitochondrial‐dependent pathway. Moreover, the sizes, morphologies and concentrations of nano‐HAP have significant effects on the apoptotic level. Copyright © 2011 John Wiley & Sons, Ltd.
Changes in 3-dimensional bone structure indices in hypoparathyroid patients treated with PTH(1-84): A randomized controlled study
Authors: Sikjaer Tanja , Rejnmark Lars , Thomsen Jesper Skovhus , Tietze Anna , Brüel Annemarie , Andersen Gratien , Mosekilde Leif
Published: December 2011

Hypoparathyroidism (hypoPT) is characterized by a state of low bone turnover and high bone mineral density (BMD) despite conventional treatment with calcium supplements and active vitamin D analogues. To assess effects of PTH substitution therapy on 3-dimensional bone structure, we randomized 62 patients with hypoPT into 24 weeks of treatment with either PTH(1-84) 100 µg/day subcutaneously or similar placebo as an add-on therapy. Micro-computed tomography was performed on 44 iliac crest bone biopsies (23 on PTH treatment) obtained after 24 weeks of treatment. Compared with placebo, PTH caused a 27% lower trabecular thickness (p < 0.01) and 4% lower trabecular bone tissue density (p < 0.01), whereas connectivity density was 34% higher (p < 0.05). Trabecular tunneling was evident in 11 (48%) of the biopsies from the PTH group. Patients with tunneling had significantly higher levels of biochemical markers of bone resorption and formation. At cortical bone, number of Haversian canals per area was 139% higher (p = 0.01) in the PTH group, causing a tendency toward an increased cortical porosity (p = 0.09). At different subregions of the hip, areal BMD (aBMD) and volumetric BMD (vBMD), as assessed by dual-energy X-ray absorptiometry (DXA) and quantitative computed tomography (QCT), decreased significantly by 1% to 4% in the PTH group. However, at the lumbar spine, aBMD decreased by 1.8% (p < 0.05), whereas vBMD increased by 12.8% (p = 0.02) in the PTH compared with the placebo group. © 2012 American Society for Bone and Mineral Research.
p‐Aminophenol‐induced cytotoxicity in Jurkat T Cells: Protective effect of 2(RS)‐n‐propylthiazolidine‐4(R)‐carboxylic acid
Authors: Chang Weiyuan , Barve Shrish , Chen Theresa S.
Published: December 2011

Acetaminophen (APAP) is hepatotoxic and can cause toxicity in Jurkat T cells. p‐Aminophenol (PAP), an industrial chemical and APAP metabolite, is nephrotoxic and hepatotoxic. Its potential toxicity in Jurkat T cells was investigated. PAP (10–250 µM) caused toxicity (decreased survival and increased LDH activity in incubation medium) and GSH depletion. At a concentration of 100 µM but not 250 µM, PAP increased DNA fragmentation. It decreased p‐Akt levels (Elisa) and at higher concentrations decreased p‐Akt expression (Western blotting). It had no effect on FasL expression. The cysteine precursor 2(RS)‐n‐propylthiazolidine‐4(R)‐carboxylic acid (250 µM) attenuated the PAP (100 µM)‐induced decrease in viability and prevented GSH depletion and increased DNA fragmentation. It attenuated the PAP‐induced decrease in p‐Akt levels and protected against the decrease in p‐Akt expression. The results demonstrate PAP‐induced toxicity and suggest that it is due at least in part to apoptosis and involves GSH depletion and p‐Akt inactivation. © 2011 Wiley Periodicals, Inc. J Biochem Mol Toxicol 26:71–78 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/jbt.20402
Virtual screening for compounds that mimic protein–protein interface epitopes
Authors: Geppert Tim , Reisen Felix , Pillong Max , Hähnke Volker , Tanrikulu Yusuf , Koch Christian P. , Perna Anna Maria , Perez Tatiana Batista , Schneider Petra , Schneider Gisbert
Published: December 2011

Modulation of protein–protein interactions (PPI) has emerged as a new concept in rational drug design. Here, we present a computational protocol for identifying potential PPI inhibitors. Relevant regions of interfaces (epitopes) are predicted for three‐dimensional protein models and serve as queries for virtual compound screening. We present a computational screening protocol that incorporates two different pharmacophore models. One model is based on the mathematical concept of autocorrelation vectors and the other utilizes fuzzy labeled graphs. In a proof‐of‐concept study, we were able to identify serine protease inhibitors using a predicted trypsin epitope as query. Our virtual screening framework may be suited for rapid identification of PPI inhibitors and suggesting bioactive tool compounds. Copyright for JCC Journal: © 2011 Wiley Periodicals, Inc. J Comput Chem, 2011
Back‐scattered electron imaging for leakage analysis of four retrofilling materials
Authors: Chittoni Simone Bücker , Martini Tassiana , Wagner Márcia Helena , Da Rosa Ricardo Abreu , Cavenago Bruno Cavalini , Duarte Marco Antônio Húngaro , Klein Celso Afonso , Só Marcus Vinícius Reis
Published: December 2011

This study aimed to evaluate, ex vivo, the nanoleakage in dentinal tubules, the linear infiltration of silver nitrate in the dentin wall/root‐end filling material interface, and the presence of gaps in this interface in root‐end cavities filled with 4 filling materials. Forty‐eight disto‐buccal root canals of maxillary molars were instrumented and filled. Retrograde cavities were prepared with ultrasonic points (apical 2 mm). The samples were divided into 2 control groups (n = 4) and 4 experimental groups (n = 10): Group I – white mineral trioxide aggregate (MTA); Group II – Super EBA; Group III – Portland cement; and Group IV – Sealer 26. After 1 week, the specimens were subjected to silver nitrate and prepared for SEM (backscattered electrons). In the apical‐apical segment, an area with significantly higher leakage was observed for Super EBA, followed by Portland cement, MTA, and Sealer 26 (P = 0.0054). In the medium and cervical segments, all materials showed the same leakage behavior (P = 0.1815 and P = 0.1723, respectively). The linear infiltration at the dentin wall/root‐end filling material interface was higher with Super EBA than the other groups. No differences in the percentage of gaps along the 3 mm of dentin wall/root‐end filling material interface between the 4 materials were evident (P > 0.05). Nanoleakage occurred mainly in the apical segment of the samples, and Super EBA showed the highest values. The area and linear leakage were lower in the middle and coronal segments, regardless of the root‐end filling material. No material perfectly sealed the root‐end cavities, which allowed for the leakage occurrence. Microsc. Res. Tech. 75:796–800, 2012. © 2011 Wiley Periodicals, Inc.
Effect of atorvastatin on the cortical bones of corticosteroid treated rabbits
Authors: Handal John A. , John Thomas K. , Goldstein Daniel T. , Khurana Jasvir S. , Saing Minn , Braitman Leonard E. , Samuel Solomon P.
Published: December 2011

Osteoporosis (“secondary” osteoporosis) and avascular necrosis (AVN) of the femoral head are well‐known adverse effects of corticosteroid therapy. Statins have been reputed to increase bone strength and bone density. In this study, we evaluated the effect of atorvastatin calcium on the flexural properties (3‐point bending strength and modulus) of corticosteroid (methylprednisolone acetate) treated rabbit femurs and tibias. Our study hypothesis was that the use of statins would counteract the loss of bone strength caused by corticosteroid treatment. The 40 rabbits were divided into 5 groups: control, corticosteroid alone and corticosteroid combined with oral doses of atorvastatin calcium (2, 10, or 20 mg/day). A daily oral dose of atorvastatin calcium treatment for 70 days weakened the long bones of methylprednisolone acetate treated rabbits irrespective of the dosage (2, 10, or 20 mg). Cortical bone strength was assessed using the 3‐point bending test at the end of the study period. A daily oral dose of atorvastatin calcium did not attenuate the loss of cortical bone strength caused by corticosteroid treatment in rabbits. It appeared to decrease that bone strength. If these results hold true in humans, they would have wide applicability given the frequent combined use of corticosteroids and statins in many patients. © 2011 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 30:872–876, 2012
Design of online solid phase extraction‐liquid chromatography‐tandem mass spectrometry (SPE‐LC‐MS/MS) hyphenated systems for quantitative analysis of small organic compounds in biological matrices
Authors: Kuklenyik Zsuzsanna , Calafat Antonia M. , Barr John R. , Pirkle James L.
Published: December 2011

Three online solid phase extraction‐liquid chromatography‐tandem mass spectrometry (SPE‐LC‐MS/MS) method examples are presented where two different types of chromatographic columns or solvent systems were coupled to meet specific analytical objectives: (i) SPE of target analytes by restricted access media from high ionic strength urine matrix was coupled with reversed phase LC‐MS/MS conditions accommodating high ionization potentials of the analytes (urinary bisphenol A and other phenolic derivatives); (ii) strong cation exchange SPE of analytes of diverse polarity and pKa was coupled with reversed phase LC‐MS/MS analysis (urinary atrazine metabolites); (iii) pre‐concentration of low pg per sample analytes by weak anion exchange SPE was hyphenated with ion pair LC‐MS analysis (intracellular nucleotide triphosphate analogs). With these examples we suggest a conductive generic work flow for the development of online SPE‐LC‐MS methods and show how advanced commercial LC devices and software allow for the design of complex yet highly versatile analytical separation systems suited to the unique physicochemical properties of the target analytes.
The economic value of publicly accessible deer hunting land
Authors: Knoche Scott , Lupi Frank
Published: December 2011

Access to lands for hunting is widely recognized as critical to sustaining and developing participation in hunting. Deer hunters comprise a substantial portion of recreational hunters in the United States, and numerous stakeholders benefit from the deer management services provided by hunters on public lands. We estimated the economic value of publicly accessible deer hunting land in Michigan using economic models of hunting destinations for hunters in the archery season and for hunters in the firearm season. We found that the amounts of state‐owned hunting land, federally owned hunting land, and publicly accessible, privately owned Commercial Forest Act land are significant (P < 0.001) and positive determinants of hunting destinations. The annual economic value of Michigan's publicly accessible hunting land to archery and firearm deer hunters, beyond hunter expenditures, was estimated to be over $80 million. Access to state‐owned land accounted for approximately $50 million in annual economic value to Michigan deer hunters. The average per‐acre value of publicly accessible hunting land is greatest in the Southern Lower Peninsula of Michigan, where public access is scarce and the majority of hunters reside. Understanding the economic values hunters derive from publicly accessible hunting lands will enable managers and policy makers to make better decisions when considering policy options that involve reducing or increasing public access. © 2011 The Wildlife Society.
A comparative study of adverse drug reactions during two heat waves that occurred in France in 2003 and 2006
Authors: Sommet Agnès , Durrieu Genevieve , Lapeyre‐Mestre Maryse , Montastruc Jean‐Louis ,   The Association of French PharmacoVigilance Centres
Published: December 2011

Purpose

Heat waves could reveal or aggravate several ‘serious’ adverse drug reactions (ADRs) in elderly. Thus, we wanted to describe the main characteristics of heat‐related ‘serious’ ADRs occurred in patients older than 70 years during these two events in France (2003 and 2006).

Methods

We analysed ‘serious’ ADRs reported to the network of French pharmacovigilance centres in summer 2003 and 2006 and suspected to be heat related. ‘Serious’ ADRs occurred during summers with heat waves (2003 and 2006) were compared with ADRs occurred during the same months in the summers of 2004 and 2005 (reference period).

Results

Patients' characteristics and number of ‘serious’ ADRs were similar whatever the year of the study. Number of drug‐related deaths seemed higher in 2003 than in 2004–2005. More ‘serious’ heat‐related ADRs were reported in the summers of 2003 and 2006 (68 in 2003 and 72 in 2006). Comparing with the reference period, metabolic ADRs were less frequent during the summers of 2003 (29%, p = 0.0001) and 2006 (39%, p = 0.003). Occurrence of other ADRs was similar whatever the period. Drugs more frequently involved during heat waves were diuretics, serotonic antidepressants, angiotensin converting inhibitors and proton pump inhibitors. Differences between 2003 and 2006 were found for non‐dopaminergic (atropinic) antiparkinsonians or antiepileptics (most frequently involved in 2006) and beta‐blockers or proton pump inhibitors (less frequently involved in 2006).

Conclusion

The present study underlines the interest of a National Pharmacovigilance Database to follow each year the role of drugs in heat‐related ADRs. This survey should be associated with other pharmacoepidemiological methods, such as case–control or population‐based studies. Copyright © 2011 John Wiley & Sons, Ltd.
Friday Letters : Connecting Students, Teachers, and Families Through Writing
Authors: Newman Terry H. , Bizzarri Sarah A.
Published: December 2011

An important part of student success in school is the involvement of families. However, the communication between students and families regarding school is often sparse at best and caregivers can feel left out as to what is happening. Friday letters improve communication between students and families and also provide a myriad of instructional opportunities. Students are taken through the optimal learning model of explicit writing instruction, shared writing experiences, and independent writing. Students write a letter to their parents each Friday detailing their behavioral and academic accomplishments. Feedback is provided to students based on individualized needs. Students are excited about this writing because it is meaningful to them and written to an authentic audience. Families are excited because they receive weekly updates regarding their child's academic and social endeavors. Teachers are excited because their students are advancing their writing skills while improving communication between students, families, and teachers.
Plasmachemisches Ätzen und Beschichten bei Atmosphärendruck
Authors: Lopez Elena , Linaschke Dorit , Dresler Birte , Dani Ines , Leyens Christoph , Beyer Eckhard
Published: December 2011

Zur industriellen Herstellung waferbasierter kristalliner Silizium‐Solarzellen kommt eine Vielzahl unterschiedlichster Technologien zum Einsatz. Die Kombination dieser Technologien erfordert ein aufwändiges Handling der Wafer, was nicht nur die Investitionskosten, sondern auch die Gefahr des Waferbruchs erhöht.

Der Einsatz von Plasmatechnologien bietet die Möglichkeit, alle Prozessschritte in der Herstellungskette kristalliner Siliziumsolarzellen ohne Nutzung nasschemischer Bäder oder Vakuumprozesse durchzuführen. Am Fraunhofer IWS wurden alle zur Solarzellenfertigung erforderlichen Ätzprozesse sowie die Abscheidung der Passivierungs‐ und Antireflexschicht mit Hilfe von Atmosphärendruck‐Plasmaprozessen erfolgreich demonstriert.
Somatic muscle specification during embryonic and post‐embryonic development in the nematode C. elegans
Authors: Krause Michael , Liu Jun
Published: December 2011

Myogenesis has proved to be a powerful paradigm for understanding cell fate specification and differentiation in many model organisms. Studies of somatic bodywall muscle (BWM) development in Caenorhabditis elegans allow us to define, with single cell resolution, the distinct hierarchies of transcriptional regulators needed for myogenesis throughout development. Although all 95 BWM cells appear uniform after differentiation, there are several different regulatory cascades employed embryonically and post‐embryonically. These, in turn, are integrated into multiple extrinsic cell signaling events. The convergence of these different pathways on the key nodal point, that is the activation of the core muscle module, commits individual cells to myogenesis. Comparisons of myogenesis between C. elegans and other model systems provide insights into the evolution of contractile cell types, demonstrating the conservation of regulatory schemes for muscles throughout the animal kingdom. WIREs Dev Biol 2012, 1:203–214. doi: 10.1002/wdev.15

This article is a U.S. Government work, and as such, is in the public domain in the United States of America.

This article is categorized under:

Gene Expression and Transcriptional Hierarchies > Regulatory Mechanisms

Invertebrate Organogenesis > Worms

Comparative Development and Evolution > Model Systems
Nanowired drug delivery for neuroprotection in central nervous system injuries: modulation by environmental temperature, intoxication of nanoparticles, and comorbidity factors
Authors: Sharma Hari Shanker , Sharma Aruna
Published: December 2011

Recent developments in nanomedicine resulted in targeted drug delivery of active compounds into the central nervous system (CNS) either through encapsulated material or attached to nanowires. Nanodrug delivery by any means is supposed to enhance neuroprotection due to rapid accumulation of drugs within the target area and a slow metabolism of the compound. These two factors enhance neuroprotection than the conventions drug delivery. However, this is still uncertain whether nanodrug delivery could alter the pharmacokinetics of compounds making it more effective or just longer exposure of the compound for extended period of time is primarily responsible for enhanced effects of the drugs. Our laboratory is engaged in understanding of the nanodrug delivery using TiO2 nanowires in CNS injuries models, for example, spinal cord injury (SCI), hyperthermia and/or intoxication of nanoparticles with or without other comorbidity factors, that is, diabetes or hypertension in rat models. Our observations suggest that nanowired drug delivery is effective under normal situation of SCI and hyperthermia as evidenced by significant reduction in the blood–brain barrier (BBB) breakdown, brain edema formation, cognitive disturbances, neuronal damages, and brain pathologies. However, when the pathophysiology of these CNS injuries is aggravated by nanoparticles intoxication or comorbidity factors, adjustment in dosage of nanodrug delivery is needed. This indicates that further research in nanomedicine is needed to explore suitable strategies in achieving greater neuroprotection in CNS injury in combination with nanoparticles intoxication or other comorbidity factors for better clinical practices. WIREs Nanomed Nanobiotechnol 2012, 4:184–203. doi: 10.1002/wnan.172

This article is categorized under:

Therapeutic Approaches and Drug Discovery > Nanomedicine for Neurological Disease
Site‐specific protein cleavage in vivo by an intein‐derived protease
Authors: Volkmann Gerrit , Volkmann Verena , Liu Xiang-Qin
Published: December 2011

Site‐specific protein cleavage is a ubiquitous process in cellular protein metabolism, yet molecular tools to provide control of protein cleavage inside living cells remain scarce. Here, we show that the C‐terminal intein fragment of the non‐canonical Ssp (Synechocystis sp. PCC6803) DnaB S1 split‐intein can be used as a site‐specific protease for in vivo protein cleavage both in bacterial and eukaryotic cells. Mutagenesis data indicate a broad tolerance of the intein‐derived protease (IP) toward the amino acid upstream of the cleavage site. Furthermore, deletion studies reveal that the recognition sequence for the IP can be as short as ten amino acids. The structural features underlying the cleavage reaction preclude unintended proteolysis of endogenous proteins, thus ensuring that negative effects on cell viability are minimal.
Bridging the Gap between Family Doctors and Regional Health Authorities
Authors: Hatcher Lydia , Howell Oscar
Published: December 2011

The communication between family doctors and regional health authorities has become more complex and fragmented over the last 2 decades. By using a novel approach, we developed a medical advisory committee structure for community physicians enshrined in the regional health authority bylaws. This has improved bilateral communication, policy making that affects patients in the community, linkages between programs and family doctors, and input into the institutional care of our patients. We believe this model could be implemented or adapted by regional health authorities elsewhere in Canada having as its ultimate goal better patient care.
Évaluer l'acceptation d'un système de gestion des données électroniques dans un établissement de soins tertiaires
Authors: Young Wendy , Klima George , Isaac Winston
Published: December 2011

La présente recherche rend compte de la satisfaction relative à l'adoption d'un système de gestion des documents électroniques dans un milieu de soins tertiaires. Une brochette de possibilités de formation et de familiarisation a été offerte: formation individuelle, portes ouvertes, formation sans inscription, cyberapprentissage, formation en classe et étude autonome. On a constaté que le profil de satisfaction à l'égard de la formation ainsi qu'à l'égard de l'utilité et de la facilité d'utilisation du système diffère selon les professions. Les administrateurs étaient les plus satisfaits, et les infirmières, les moins satisfaites. On pouvait faire une association entre la participation aux portes ouvertes et la satisfaction envers le système.
Dust ion-acoustic solitary structures in non-thermal dusty plasma
Authors: DAS ANIMESH , BANDYOPADHYAY ANUP , DAS K. P.
Published: December 2011

Dust ion-acoustic solitary structures have been investigated in an unmagnetized non-thermal plasma consisting of negatively charged dust grains, adiabatic positive ions, and non-thermal electrons. Whenever the non-thermal parameter exceeds a critical value, the present system supports negative potential double layer solution. However, this double layer solution is unable to restrict the occurrence of negative potential solitary waves of the present system. As a result, the occurrence of one type of negative potential solitary wave is restricted by Mc < M < MD, whereas the second type of solitary wave exists for all M > MD, where Mc is the lower bound of the Mach number M and MD (> Mc) is the Mach number corresponding to a negative potential double layer. A finite jump between the amplitudes of negative potential solitary waves at M = MD − ϵ1 and M = MD + ϵ2 has been observed, where 0 < ϵ1 < MD − Mc and ϵ2 > 0. Depending on the analytical theory presented in this paper, a numerical scheme has been provided to find the value of the Mach number at which double layer solution exists, and also the amplitude of that double layer. Although the occurrence of coexistence of solitary structures of both polarities is restricted by Mc < M ≤ Mmax, only negative potential solitary wave still exists for all M > Mmax, where Mmax is the upper bound of M for the existence of positive potential solitary waves only. Qualitatively different compositional parameter spaces showing the nature of existing solitary structures of the energy integral have been found. These solution spaces are capable of producing new results and physical ideas for the formation of solitary structures whenever one can move the solution spaces through the family of curves parallel to the curve M = Mc.
Covariation between understorey light environments and soil resources in Bornean mixed dipterocarp rain forest
Authors: Russo Sabrina E. , Zhang Lin , Tan Sylvester
Published: December 2011

Variation in understorey irradiance is both a cause and consequence of the structure and dynamics of closed-canopy forests, which are also influenced by soil nutrients and water availability. We tested the hypothesis that understorey light regimes differ among four mixed dipterocarp forest types that share the same rainfall, but grow on different soils along an edaphic gradient at one site in Borneo. Based on data from photosynthetically active radiation sensors deployed at 1-m height at 36 locations for 351 sensor-days, we found significant soil-related variation in irradiance. The more productive forest types on clay and fine loam had lower daily photosynthetic photon flux density (PPFD) than those on the more nutrient-depleted and better-drained sandy loam and loam. They also had fewer moderate to high-intensity sunflecks, and a greater proportion of their daily PPFD came from low-intensity light. Understorey irradiance did not, however, monotonically decline with increasing soil resources. Forests on intermediate soils had greater irradiance than those with more and less soil resources, due to steeper slopes. Plant communities arrayed on resource gradients are commonly used to test hypotheses of environmental factors driving their assembly. Our results indicate that consideration of multiple resource dimensions in such tests is critical.
Control of Carapa guianensis phenology and seed production at multiple scales: a five-year study exploring the influences of tree attributes, habitat heterogeneity and climate cues
Authors: Klimas Christie A. , Kainer Karen A. , Wadt Lúcia H. , Staudhammer Christina L. , Rigamonte-Azevedo Valéria , Correia Manoel Freire , da Silva Lima Lílian Maria
Published: December 2011

During 5 y, we monitored reproductive activity and seed production of Carapa guianensis in two forest types to test the hypothesis that seed production is influenced by multiple factors across scales (regional climatic cues, local habitat heterogeneity and individual tree attributes). Variability in seed production was moderate at the population (CVp = 1.25) and individual level (xCVi = 1.24). A mixed model with a Poisson regression revealed that seed production was explained by variables at all scales. Total seed production was significantly higher in occasionally inundated forests. Diameter at breast height, dbh2, crown cross-sectional area, liana load, density, dry-season rainfall and mean maximum temperature were also significant in explaining seed production variation. Seed production increased with dbh until 40–50 cm, then decreased. Liana load demonstrated a negative relationship with seed production, but only in terra firme forests. Climatic cues (rainfall and temperature parameters) were central to setting overall patterns in reproductive activity and seemed to best explain why years with high seed production were consistent across the two forest types (habitats) examined. Dry-season rainfall was positively correlated with seed production.
On measuring phonetic precursor robustness: a response to Moreton
Authors: Yu Alan C. L.
Published: December 2011

Much debate in recent years has focused on the relative contribution of analytic and channel biases in shaping the typology of sound. Moreton (2008) argues forcefully for the strength of analytic bias, such as Universal Grammar and other non-modality-specific cognitive biases that facilitate the learning of some phonological patterns and inhibit that of others, in creating typological asymmetries on its own, unassisted by the robustness of phonetic precursors. This article focuses on the assessment of phonetic precursor robustness. The main goal of this article is two-fold: (i) to establish the inadequacy of Moreton's method of evaluating relative phonetic precursor robustness and to offer an alternative to his approach; (ii) to report the results of a cross-linguistic study comparing the nature of vowel-to-vowel coarticulation and the interaction between obstruent voicing and vowel height with the same languages – no previous studies have directly compared these two phonetic precursors.
Marx, Necessity and Science
Authors: Ruben D.-H.
Published: December 2011

Among the very many questions we might wish to ask of any particular
science, two of them concern the nature of the objects of the science and
the character of the laws which describe the behaviour of those objects.
What I wish to do is to raise those two questions about historical
materialism. That is, I want to ask what it is
that one studies in Capital for example, and
in what ways of behaving does the nomic or
lawlike behaviour of those objects consist. Both are ontological questions
of a sort, and, in particular, questions about what I call social ontology,
although it is usual to restrict the term ‘ontological’ to the former
question alone. The first question asks about the objects to whose existence
historical materialism is committed; the second asks about the
characteristic ways of behaving of those objects.
Macherey and Marxist Literary Theory
Authors: Eagleton Terry
Published: December 2011

A resurgence of interest in the materialist aesthetics of Walter
Benjamin and Bertolt Brecht has helped to free Marxist criticism from the
neo-Hegelian forms within which it has long been imprisoned. Yet the central
category of those materialist aesthetics—the ‘author as producer’—remains a
transitional concept, potently
demystificatory but politically indeterminate. And crucial though the
analysis of the relations between ‘base’ and ‘superstructure’
within art itself clearly is, its historical
explanatory power is not yet fully evident. The moment of Brecht, for
example, is not easily translatable to English literary culture. Donne's
Songs and Sonnets and George Herbert's
The Temple belong to different modes of
literary production, but inhabit alternative areas of the same ideological
formation; Defoe and Fielding practise the same mode of literary production,
but it is their ideological antagonism which claims our attention.
Henry Esmond was the only novel of Thackerary
to be published complete, rather than in monthly serialized parts; but
though this difference of productive mode undoubtedly impresses itself on
the novel's form, it leaves the ‘Thackerayan ideology’ essentially intact.
No one expects modes of literary production and literary ‘superstructures’
to form a symmetrical relationship, dancing a harmonious minuet hand-in-hand
throughout history; yet even if we allow for disjunction and uneven
development, it seems true that the ‘author as producer’ concept is one
which must, as it were, lie dormant over certain spans of literary history.
The aesthetic redefinition of fiction as ‘organic form’ which develops in
late nineteenth-century England, to discover its major ideologue in Henry
James, is doubtless related to those shifts in literary production (from
serialization and the ‘three-decker’ novel to the single volume) determined
by the economic demands of the monopolist private lending libraries; yet it
is not clear how such material mutations become an
active element in the reconstruction of
fictional ideologies.
Althusser: How to be a Marxist in Philosophy
Authors: O'Hagan Timothy
Published: December 2011

Althusser called a recent essay: ‘Is it simple to be a Marxist in
philosophy?’ My title, intentionally provocative, echoes that question.
Following Althusser, I shall answer it in the negative and, in so doing,
shall raise a series of further questions concerning the nature of and
connections between politics, science and philosophy. My lecture will keep
turning on these three points, just as Althusser's own work has turned on
them, ever since his first book, a monograph on Montesquieu, up to his most
recent critical interventions on the role and organization of the French
Communist Party in the 1970s. In an interview given in 1968,
characteristically entitled ‘Philosophy as a revolutionary weapon’,
Althusser linked the three points in an autobiographical comment:

In 1948, when I was thirty, I became a teacher of philosophy and joined
the French Communist Party. Philosophy was an interest; I was trying to make
it my profession. Politics was a passion; I was trying to become a communist
militant.
Challenges for efficient health service delivery: experiences of dietitians completing their compulsory community service year in South Africa
Authors: Parker Whadi-ah , Steyn Nelia P , Mchiza Zandile , Wentzel-Viljoen Edelweiss , Dannhauser Andre , Mbhenyane Xikombiso , Nthangeni Gladys , Moeng Lynn
Published: December 2011

Objective

To evaluate the successes and shortcomings of the community service programme implemented by the Department of Health (DOH) in South Africa by evaluating community service dietitians’ experiences and challenges during the 2009 community service year.

Design

The study employed both quantitative and qualitative research designs. A national survey was conducted using a questionnaire to illicit information on community service dietitians’ working environments and the challenges they experienced. Furthermore individual interviews were conducted with a purposively selected subsample of community service dietitians to further explore issues that arose in the survey.

Setting

Data were collected from community service dietitians in the public health sector in South Africa.

Subjects

Dietitians completing their community service year in 2009.

Results

Of the 168 community service dietitians placed in 2009, 134 (80 %) participated in the survey, while five community service dietitians in each province (n 45) were interviewed. Overall the community service dietitians were positive about the community service year and reported that it improved their confidence, skills and competencies. However, they experienced challenges related to the orientation programme, supervision/mentoring, resources available, patient referrals and communication.

Conclusions

Despite the overall success of the community service year there are still challenges which the DOH needs to address in order to provide the best nutrition service possible for its patients.
Why Study Law? The Relevance of Legal Information to the Law Student, Researcher and Practitioner
Authors: Virgo Graham
Published: December 2011

Professor Graham Virgo, in delivering the 3rd Willi Steiner Memorial Lecture, asks if it is possible to become a legal practitioner in England and Wales without having studied Law as an academic discipline. Is there any point in studying for a Law degree? Students study any academic subject to acquire knowledge and to develop key skills. This is just as true of students studying Law. But is the knowledge acquired by a Law student and the skills which they develop really of benefit to them in legal practice? Crucially, what can the managers of legal information do to support the particular needs of Law students and academic researchers?
SLS/BIALL Academic Law Library Survey 2009/2010
Authors: Clinch Peter
Published: December 2011

This is the latest report analysing the results of the survey conducted on behalf of the Society of Legal Scholars and BIALL. It has been written by Peter Clinch, formerly Senior Subject Librarian for Law, Cardiff University
Response to Steven L. Taylor's review of Violent Democracies in Latin America
Authors: Arias Desmond
Published: December 2011

I want to thank Steven Taylor for his thoughtful comments on the volume Daniel Goldstein and I edited. In this response I will address two key points he raises that help to highlight some of the key differences in our approaches.
A Realist Foreign Policy for the United States
Authors: Rosato Sebastian , Schuessler John
Published: December 2011

What kind of policy can the United States pursue that ensures its security while minimizing the likelihood of war? We describe and defend a realist theory of foreign policy to guide American decision makers. Briefly, the theory says that if they want to ensure their security, great powers such as the United States should balance against other great powers. They should also take a relaxed view toward developments involving minor powers and, at most, should balance against hostile minor powers that inhabit strategically important regions of the world. We then show that had the great powers followed our theory's prescriptions, some of the most important wars of the past century might have been averted. Specifically, the world wars might not have occurred, and the United States might not have gone to war in either Vietnam or Iraq. In other words, realism as we conceive it offers the prospect of security without war. At the same time, we also argue that if the United States adopts an alternative liberal foreign policy, this is likely to result in more, rather than fewer, wars. We conclude by offering some theoretically-based proposals about how US decision makers should deal with China and Iran.
Reply to Evgeny Morozov's review of The Digital Origins of Dictatorship and Democracy: Information Technology and Political Islam
Authors: Howard Philip N.
Published: December 2011

Morozov is absolutely right to point out that other countries—not in the set analyzed in Digital Origins—might reveal different paths toward or away from democratic government. But a quick look at some of the examples shows that they do not directly conflict with my argument that the proliferation of consumer electronics in countries with an active civil society and limited resource wealth seems to come with democratic consequences. China, Cuba, North Korea, Iran, Russia, and Venezuela are often offered as examples of how a tough regime can use digital media to oppress their citizens.
Utilizing cover crop mulches to reduce tillage in organic systems in the southeastern USA
Authors: Reberg-Horton S. Chris , Grossman Julie M. , Kornecki Ted S. , Meijer Alan D. , Price Andrew J. , Place George T. , Webster Theodore M.
Published: December 2011

Organic systems in the southeastern USA offer unique challenges and solutions to crop production due to regional soil and climate characterized by highly weathered soil types, high precipitation and the capacity to grow cover crops in the winter. Recently, the interest of producers and researchers in high-residue cover crops and conservation tillage systems has increased. Various designs of the roller–crimper to manage cover crops have been invented and demonstrated to growers in the southeastern region of the USA over the past 17 years. The impacts of high-residue cover crop mulches on the agronomic systems in the region are diverse. Legume cover crops assist with meeting N demand from cash crops though they decompose rapidly and are seldom sufficient for N demanding crops such as corn. Cereal cover crop mulches can have the opposite effect by immobilizing N and have a longer impact on soil moisture and weed dynamics. While undesirable for many crops, N immobilization is one possible mechanism for weed suppression in legume cash crops planted into cereal residues. Other cover crop weed suppression mechanisms include physical impedance, light availability, allelopathy and microclimate effects. Regardless of the cause, successful weed control by mulches is highly dependent on having substantial biomass. The southeastern region is capable of producing cover crop biomass in excess of 9000 kg ha−1, which is sufficient for weed control in many cash crops, although supplementary weed control is sometimes necessary. Long-term data are needed to predict when farmers should add supplementary weed control. More work is also needed on how much additional N is required for the cash crops and how best to deliver that N in a high-residue environment using organic sources.
Storm and substorm effects on magnetotail current sheet motion
Authors: Davey E. A. , Lester M. , Milan S. E. , Fear R. C.
Published: December 2011

Passes through the mid‐region of the magnetotail by the Cluster spacecraft from 2001 to 2007 have been examined to study the dynamics of the cross‐tail current sheet. Cluster is ideally placed to study this region due to the orientation of the orbit in the magnetotail, such that the current sheet is sampled at distances downtail from about 8–19 RE. Multiple fluctuations of the X component of the magnetic field (BX) from positive to negative and vice versa, measured by Cluster as it crosses the nominal location of the current sheet, indicate that the current sheet is in motion. In this study we use the number of crossings of the current sheet by the Cluster 3 spacecraft as a measure of the dynamics of the magnetotail. The effects of substorm and magnetic storm activity on the dynamics during these orbits have been investigated using the AE and SYM‐H indices. Our results indicate that the current sheet is more often in motion during orbits when there is greater than average substorm activity and a quiet ring current. Results suggest that internal processes within the tail that initiate substorms may also initiate the flapping motion of the current sheet. In addition the more dipolar field that results from an enhanced ring current during magnetic storms may inhibit tail dynamics during substorm events.
Aerodynamics of stratovolcanoes during multiphase processes
Authors: Doronzo Domenico M. , Martí Joan , Sulpizio Roberto , Dellino Pierfrancesco
Published: December 2011

Pyroclastic density currents (PDCs) are gas‐particle flows generated during explosive eruptions, which are often erupted over the flanks of stratovolcanoes. These volcanoes may have different shapes, which can affect the flow aerodynamics and hence the depositional processes. Here, multiphase numerical simulations are carried out in order to define semiquantitative relationships among the PDC behavior, particle response, and deposit formation. Three stratovolcano shapes are used: straight, convex and concave, and, by means of numerical simulations, their effects both on the flow structure and depositional processes are highlighted. The current starts moving as a homogeneous flow, and then it rapidly evolves to a turbulent boundary layer moving in contact with the ground, overlaid by a companion wake region. Results show that thin boundary layers produce thick deposits of massive layers, whereas thick boundary layers produce thin laminated deposits. Moreover, concave wake regions would produce thick massive deposits of fine ash, whereas convex wake regions would produce thin ash deposits.
On the relationship between QBO and distribution of tropical deep convection
Authors: Liess Stefan , Geller Marvin A.
Published: December 2011

There have been several observational and modeling analyses that have indicated that the stratospheric quasi‐biennial oscillation (QBO) significantly affects the tropical troposphere. This article aims to identify the QBO signal in tropical deep convection. Some difficulties in previous studies were ambiguities in the identification of tropical deep convection in observations, and also in separating the El Niño/Southern Oscillation (ENSO) and other tropospheric signals from QBO influences. We use a recent cluster analysis of 21.5 years of International Satellite Cloud Climatology Project tropical weather states to identify tropical deep convection and cirrus clouds, as well as 32.25 years of precipitation data as proxies for deep convection. Correlations between the QBO, ENSO, and other tropospheric patterns such as the tropospheric biennial oscillation and Pacific decadal oscillation are taken into account to isolate the influence of the QBO. Whereas tropical deep convection is mostly related to ENSO and the annual cycle, the QBO westerly phase, independent of the annual cycle as well as linear and nonlinear impacts of ENSO, leads to an eastward shift in the strength of meridional overturning contributions to the Hadley circulation over the Pacific and thus also affects the subtropical circulation. For deep convective clouds, relative differences in convective cloud cover between the QBO easterly and QBO westerly phases can be as large as 51% ± 7% of the annual average over isolated regions in the tropical west Pacific and 103% ± 35% over the east Pacific, where the absolute values are lower and where notable deviations occur during the QBO westerly phase.