bluuebunny/crossref_metadata_2025 huggingface dataset:
Lead-free acoustic emission sensors
Authors: Lam K. H. , Lin D. M. , Chan H. L. W.
Published: November 2007

Acoustic emission (AE) sensors have been fabricated using both soft- and hard-type lead-free (Na0.5K0.5)NbO3-based ceramics. The acoustic and electromechanical properties of the ceramics have been determined using the resonance technique. The lead-free AE sensors were calibrated using a laser source and compared to a commercial sensor. A lead zirconate titanate (PZT) 5H ceramics AE sensor has also been fabricated and calibrated for comparison. It was found that the sensitivity of lead-free AE sensors is comparable to that of the lead-based PZT sensor. To evaluate the sensors for potential application, they have been used in the detection of AE in an impact test. The lead-free sensors can reproduce AE signals accurately without giving artifacts and have potential use in commercial AE systems.
Optical anisotropy of InGaAs∕Ga(As,P) quantum dots grown on GaAs (311)B substrates
Authors: Zhang Y. C. , Pancholi A. , Stoleru V. G. , Hanna M. C. , Norman A. G.
Published: November 2007

Very high quality structures consisting of multilayer InGaAs quantum dots (QDs) were grown on (311)B GaAs by introducing strain-compensated Ga(As,P) barriers between adjacent QD layers. The dot optical anisotropy was studied by performing polarized photoluminescence (PL) measurements both on the surface and the edges of the samples. The observed in-plane optical anisotropy of the dots can be eventually related to the direction and the extent of the dot strain relaxation. The transverse electric mode of the edge-emitted PL showed about 5° deviation from the sample surface for the dots grown on (311)B GaAs. This can be attributed to the tilted vertical alignment and the shape asymmetry of dots resulted from the substrate orientation.
Ultrahigh photocurrent gain in m-axial GaN nanowires
Authors: Chen Reui-San , Chen Hsin-Yi , Lu Chien-Yao , Chen Kuei-Hsien , Chen Chin-Pei , Chen Li-Chyong , Yang Ying-Jay
Published: November 2007

An ultrahigh photocurrent gain has been found in the ultraviolet-absorbed GaN nanowires with m-directional long axis grown by chemical vapor deposition. The quantitative results have shown the gain values at 5.0×104–1.9×105 of the GaN nanowires with diameters from 40to135nm are near three orders of magnitude higher than the values of 5.2×101–1.6×102 estimated from the thin film counterparts. The intensity-dependent gain study has shown that the gain value is very sensitive to the excitation intensity following an inverse power law and no gain saturation observed in this investigated intensity range from 0.75to250W∕m2. This behavior has strongly suggested a surface-dominant rather than trap-dominant high gain mechanism in this one-dimensional nanostructure. The strong carrier localization effect induced by the surface electric field in the GaN nanowires is also discussed.
Nondegenerate three-dimensional complex Euclidean superintegrable systems and algebraic varieties
Authors: Kalnins E. G. , Kress J. M. , Miller W.
Published: November 2007

A classical (or quantum) second order superintegrable system is an integrable n-dimensional Hamiltonian system with potential that admits 2n−1 functionally independent second order constants of the motion polynomial in the momenta, the maximum possible. Such systems have remarkable properties: multi-integrability and multiseparability, an algebra of higher order symmetries whose representation theory yields spectral information about the Schrödinger operator, deep connections with special functions, and with quasiexactly solvable systems. Here, we announce a complete classification of nondegenerate (i.e., four-parameter) potentials for complex Euclidean 3-space. We characterize the possible superintegrable systems as points on an algebraic variety in ten variables subject to six quadratic polynomial constraints. The Euclidean group acts on the variety such that two points determine the same superintegrable system if and only if they lie on the same leaf of the foliation. There are exactly ten nondegenerate potentials.
The Perception of Space and Form Recognition in a Simulated Environment: The Case of Minimalist Sensory-Substitution Devices
Authors: Auvray Malika , Philipona David , O'Regan J Kevin , Spence Charles
Published: November 2007

Whenever we explore a simulated environment, the sensorimotor interactions that underlie our perception of space may be modified. We investigated the conditions under which it is possible to acquire the mastery of new sensorimotor laws and thereby to infer new perceptual spaces. A computer interface, based on the principles of minimalist sensory-substitution devices, was designed to enable different possible links between a user's actions (manipulation of a mouse and/or keys of a keyboard) and the resulting pattern of sensory stimulation (visual or auditory) to be established. The interface generated an all-or-none stimulus whose activation varied as a function of the participant's exploration of a hidden form. In this study we addressed the following questions: What are the conditions necessary for participants to understand their actions as constituting a displacement in a simulated space? What are the conditions required for participants to conceive of sensations as originating from the encounter with an object situated in this space? Finally, what are the conditions required for participants to recognise forms within this space? The results of the two experiments reported here show that, under certain conditions, participants can interpret the new sensorimotor laws as movements in a new perceptual space and can recognise simple geometric forms, and that this occurs no matter whether the sensory stimulation is presented in the visual or auditory modality.
Modulation of metabolic brain networks after subthalamic gene therapy for Parkinson's disease
Authors: Feigin Andrew , Kaplitt Michael G. , Tang Chengke , Lin Tanya , Mattis Paul , Dhawan Vijay , During Matthew J. , Eidelberg David
Published: November 2007

Parkinson's disease (PD) is characterized by elevated expression of an abnormal metabolic brain network that is reduced by clinically effective treatment. We used fluorodeoxyglucose (FDG) positron emission tomography (PET) to determine the basis for motor improvement in 12 PD patients receiving unilateral subthalamic nucleus (STN) infusion of an adenoassociated virus vector expressing glutamic acid decarboxylase (AAV-GAD). After gene therapy, we observed significant reductions in thalamic metabolism on the operated side as well as concurrent metabolic increases in ipsilateral motor and premotor cortical regions. Abnormal elevations in the activity of metabolic networks associated with motor and cognitive functioning in PD patients were evident at baseline. The activity of the motor-related network declined after surgery and persisted at 1 year. These network changes correlated with improved clinical disability ratings. By contrast, the activity of the cognition-related network did not change after gene transfer. This suggests that modulation of abnormal network activity underlies the clinical outcome observed after unilateral STN AAV-GAD gene therapy. Network biomarkers may be used as physiological assays in early-phase trials of experimental therapies for PD and other neurodegenerative disease.
A dual function for a bacterial small RNA: SgrS performs base pairing-dependent regulation and encodes a functional polypeptide
Authors: Wadler Caryn S. , Vanderpool Carin K.
Published: November 2007

SgrS is a 227-nt small RNA that is expressed in
Escherichia coli
during glucose-phosphate stress, a condition associated with intracellular accumulation of glucose-6-phosphate caused by disruption of glycolytic flux. Under stress conditions, SgrS negatively regulates translation and stability of the
ptsG
mRNA, encoding the major glucose transporter, by means of a base pairing-dependent mechanism requiring the RNA chaperone Hfq. SgrS activity mitigates the effects of glucose-phosphate stress, and the present study has elucidated a function of SgrS that is proposed to contribute to the stress response. The 5′ end of SgrS, upstream of the nucleotides involved in base pairing with the
ptsG
mRNA, contains a 43-aa ORF,
sgrT
, that is conserved in most species that contain SgrS-like small RNAs. The
sgrT
gene is translated in
E. coli
under conditions of glucose-phosphate stress. Analysis of alleles that separate the base pairing function of SgrS from the
sgrT
coding sequence revealed that either of these functions alone are sufficient for previously characterized SgrS phenotypes. SgrS-dependent down-regulation of
ptsG
mRNA stability does not require SgrT and SgrT by itself has no effect on
ptsG
mRNA stability. Cells expressing
sgrT
alone had a defect in glucose uptake even though they had nearly wild-type levels of PtsG (IICB
Glc
). Together, these data suggest that SgrS represents a previously unrecognized paradigm for small RNA (sRNA) regulators as a bifunctional RNA that encodes physiologically redundant but mechanistically distinct functions contributing to the same stress response.
In vivo
multiphoton microscopy of NADH and FAD redox states, fluorescence lifetimes, and cellular morphology in precancerous epithelia
Authors: Skala Melissa C. , Riching Kristin M. , Gendron-Fitzpatrick Annette , Eickhoff Jens , Eliceiri Kevin W. , White John G. , Ramanujam Nirmala
Published: November 2007

Metabolic imaging of the relative amounts of reduced NADH and FAD and the microenvironment of these metabolic electron carriers can be used to noninvasively monitor changes in metabolism, which is one of the hallmarks of carcinogenesis. This study combines cellular redox ratio, NADH and FAD lifetime, and subcellular morphology imaging in three dimensions to identify intrinsic sources of metabolic and structural contrast
in vivo
at the earliest stages of cancer development. There was a significant (
P
< 0.05) increase in the nuclear to cytoplasmic ratio (NCR) with depth within the epithelium in normal tissues; however, there was no significant change in NCR with depth in precancerous tissues. The redox ratio significantly decreased in the less differentiated basal epithelial cells compared with the more mature cells in the superficial layer of the normal stratified squamous epithelium, indicating an increase in metabolic activity in cells with increased NCR. However, the redox ratio was not significantly different between the superficial and basal cells in precancerous tissues. A significant decrease was observed in the contribution and lifetime of protein-bound NADH (averaged over the entire epithelium) in both low- and high-grade epithelial precancers compared with normal epithelial tissues. In addition, a significant increase in the protein-bound FAD lifetime and a decrease in the contribution of protein-bound FAD are observed in high-grade precancers only. Increased intracellular variability in the redox ratio, NADH, and FAD fluorescence lifetimes were observed in precancerous cells compared with normal cells.
The P2 capsid protein of the nonenveloped rice dwarf phytoreovirus induces membrane fusion in insect host cells
Authors: Zhou Feng , Pu Yingying , Wei Taiyun , Liu Huijun , Deng Wulan , Wei Chunhong , Ding Biao , Omura Toshihiro , Li Yi
Published: November 2007

Insect transmission is an essential process of infection for numerous plant and animal viruses. How an insect-transmissible plant virus enters an insect cell to initiate the infection cycle is poorly understood, especially for nonenveloped plant and animal viruses. The capsid protein P2 of rice dwarf virus (RDV), which is nonenveloped, is necessary for insect transmission. Here, we present evidence that P2 shares structural features with membrane-fusogenic proteins encoded by enveloped animal viruses. When RDV P2 was ectopically expressed and displayed on the surface of insect
Spodoptera frugiperda
cells, it induced membrane fusion characterized by syncytium formation at low pH. Mutational analyses identified the N-terminal and a heptad repeat as being critical for the membrane fusion-inducing activity. These results are corroborated with results from RDV-infected cells of the insect vector leafhopper. We propose that the RDV P2-induced membrane fusion plays a critical role in viral entry into insect cells. Our report that a plant viral protein can induce membrane fusion has broad significance in studying the mechanisms of virus entry into insect cells and insect transmission of nonenveloped plant and animal viruses.
Evolutionary plasticity of developmental gene regulatory network architecture
Authors: Hinman Veronica F. , Davidson Eric H.
Published: November 2007

Sea stars and sea urchins evolved from a last common ancestor that lived at the end of the Cambrian, approximately half a billion years ago. In a previous comparative study of the gene regulatory networks (GRNs) that embody the genomic program for embryogenesis in these animals, we discovered an almost perfectly conserved five-gene network subcircuit required for endoderm specification. We show here that the GRN structure upstream and downstream of the conserved network kernel has, by contrast, diverged extensively. Mesoderm specification is accomplished quite differently; the Delta–Notch signaling system is used in radically distinct ways; and various regulatory genes have been coopted to different functions. The conservation of the conserved kernel is thus the more remarkable. The results indicate types of network linkage subject to evolutionary change. An emergent theme is that subcircuit design may be preserved even while the identity of genes performing given roles changes because of alteration in their
cis
-regulatory control systems.
Three-dimensional computational holographic imaging and recognition using independent component analysis
Authors: Do Cuong Manh , Javidi Bahram
Published: November 2007

We present computational holographic three-dimensional imaging and automated object recognition based on independent component analysis (ICA). Three-dimensional sensing of the scene is performed by computational holographic imaging of the objects using phase-shifting digital holography. We used principal components analysis to reduce data dimension and ICA to recognize the three-dimensional objects. In this paper, kurtosis maximization-based algorithm is used. To the best of our knowledge, this paper is the first to report using ICA in three-dimensional imaging technology.
Robust recognition of zinc binding sites in proteins
Authors: Ebert Jessica C. , Altman Russ B.
Published: November 2007

Metals play a variety of roles in biological processes, and hence their presence in a protein structure can yield vital functional information. Because the residues that coordinate a metal often undergo conformational changes upon binding, detection of binding sites based on simple geometric criteria in proteins without bound metal is difficult. However, aspects of the physicochemical environment around a metal binding site are often conserved even when this structural rearrangement occurs. We have developed a Bayesian classifier using known zinc binding sites as positive training examples and nonmetal binding regions that nonetheless contain residues frequently observed in zinc sites as negative training examples. In order to allow variation in the exact positions of atoms, we average a variety of biochemical and biophysical properties in six concentric spherical shells around the site of interest. At a specificity of 99.8%, this method achieves 75.5% sensitivity in unbound proteins at a positive predictive value of 73.6%. We also test its accuracy on predicted protein structures obtained by homology modeling using templates with 30%–50% sequence identity to the target sequences. At a specificity of 99.8%, we correctly identify at least one zinc binding site in 65.5% of modeled proteins. Thus, in many cases, our model is accurate enough to identify metal binding sites in proteins of unknown structure for which no high sequence identity homologs of known structure exist. Both the source code and a Web interface are available to the public at http://feature.stanford.edu/metals.
Properties of spray‐dried and freeze‐dried faba bean protein concentrates
Authors: Otegui I. , Fernández‐Quintela A. , Diego A. De , Cid C. , Macarulla M. T. , Partearroyo M. A.
Published: November 2007

Summary  A protein concentrate from faba bean seeds was prepared by isoelectric precipitation and spray‐dried. Its functional properties were measured and the results obtained were compared to those from another concentrate prepared by the classical freeze‐drying technique. The functional properties were found to be indistinguishable. However, the protein solubility profile was different depending on the preparation technique. Some antinutritional factors (trypsin inhibitors, tannins and phytates) were also analysed. Both protein concentrates showed lower concentrations of tannins and phytates than the seeds.
Modelling shrinkage and porosity during vacuum dehydration
Authors: Krokida Magdalini K. , Zogzas Nikolaos P. , Maroulis Zacharias B.
Published: November 2007

Summary  Apparent density, true density, specific volume and internal porosity were investigated during vacuum dehydration of banana, apple, carrot and potato, at various moisture contents and pressures. The pressure was found to effect significantly the apparent density and porosity of the materials examined, while for the true density, this effect was practically negligible. In all four materials the development of porosity was favoured by the decrease of pressure. At the lowest pressure used (30 mbars) banana and apple developed the highest porosity values (∽75%), followed by those of carrot (∽50%) and potato (‐25%). A simple mathematical model was proposed to predict the above properties as functions of material moisture content and pressure. The parameters incorporated into the model were: the enclosed water density, the dry solids density, the apparent density of the dry material, and a transformed volume‐shrinkage coefficient. Among these parameters, only the apparent density of the dry material was found to be strongly affected by the pressure and a suitable exponential equation was proposed to express this influence. The proposed model was fitted to the experimental data satisfactorily, and the required parameters were estimated through a regression analysis procedure.
Improving the nutritional value of wheat bran by a white‐rot fungus
Authors: Lena Gabriella Di , Patroni Elvira , Quaglia G. B.
Published: November 2007

Summary  This investigation was concerned with the solid‐state cultivation of the white‐rot fungus Lentinula edodes on wheat bran and its impact on the nutritional value of the substrate. A considerable reduction (60%) in the concentration of the phytic acid of wheat bran was detected after 7 days of incubation, but no further reduction was observed during the following weeks. Protein digestibility increased gradually during the first 3 weeks of incubation reaching a maximum (82%) at day 20. Hydrolytic and oxidative exoenzymes, such as phytase, endocellulase and polyphenol oxidase, were released by the mycelium during the colonization of the substrate. Total and insoluble dietary fibre and crude protein content in bran increased with fungal growth while the in vitro dry matter enzyme digestibility decreased.
Safety assessment of genetically engineered yeast: elimination of mutagenicity of the yeast Saccharomyces cerevisiae by decreasing the activity of methylglyoxal synthase
Authors: Hashimoto Wataru , Inose Tomoko , Masuda Keiko , Murata Kousaku
Published: November 2007

Summary  Methylglyoxal synthase catalyses the transformation of dihydroxyacetonephosphate to methylglyoxal, a toxic 2‐oxoaldehyde which is found to be present in the yeast Saccharomyces cerevisiae DKD‐5D‐H. Yeast cells in which genes for phosphoglucose isomerase, phosphofructokinase and triosephosphate isomerase had been extrachromosomally amplified by using a multi‐copy plasmid showed an increased ability to induce mutagenesis in standard tests when compared to wild type yeast. This response is mainly due to the increased amount of methylglyoxal in the engineered cells. To decrease the mutagenic activity and make it possible to use genetically engineered yeasts for practical fermentation processes, a mutant having a decreased level of methylglyoxal synthase activity was isolated. When transformed with genes for the glycolytic enzymes, the mutant cells showed extremely low levels of methylglyoxal content and mutagenic activity, both levels being comparable with those of non‐transformed DKD‐5D‐H cells.
Comparison between an odour profile and a flavour profile of dry fermented sausages
Authors: Rousset‐Akrim Sylvie , Martin Jean‐Francis , Bayle Marie‐Christine , Berdagué Jean‐Louis
Published: November 2007

Summary  Two preparations of dry fermented sausage inoculated with one of four different strains of Staphylococcus were prepared a week apart and tested twice by 10 trained assessors. Profiles of eight attributes (vinegar, dry sausage, fat, dry cured‐ham, pâté, milk, butter and nutty) were monadically assessed twice and scored on non‐structured scales. During the first two sessions subjects tasted twice the four dry sausages from both preparations, and during the last two sessions 7 days later they assessed the odour of the same samples in duplicate by sparging with air. Principal component analysis showed that the eight samples (four strains X two preparations) of dry sausage were described similarly by tasting and sniffing except for the fat attribute. The principal component analysis showed that the eight samples of dry sausage were better discriminated by smell than by taste. The smelling procedure resulted in a better recognition of dry sausages inoculated with the same strain of Staphylococcus than that by tasting. Variance analysis showed that product effect was significant on common odour and flavour attributes: ‘vinegar’, ‘fat’ and ‘butter’; and it was never significant on ‘nutty’ and ‘pâté’. The F‐values for ‘vinegar’, ‘fat’, ‘dry‐ham’, ‘milk’ and ‘butter’ were higher by smell than by taste. Only ‘dry‐sausage’ was better distinguished by taste.
Heart valve disease associated with treatment with ergot‐derived dopamine agonists: a clinical and echocardiographic study of patients with Parkinson’s disease
Authors: Rasmussen V. G. , Poulsen S. H. , Dupont E. , Østergaard K. , Safikhany G. , Egeblad H.
Published: November 2007

Objective. To elucidate the association between treatment with ergot‐derived dopamine agonists (EDDA) and valvular abnormalities amongst patients with idiopathic Parkinson’s disease (IPD) and secondly, to analyse the yield of clinical screening for valvular heart disease.

Design. A cross‐sectional controlled study.

Setting. The cohort of IPD patients treated in the outpatient clinic, Department of Neurology, Aarhus University Hospital, Denmark.

Subjects. A total of 138 IPD patients [median age 64 (39–87) years, 62% men] treated with either EDDA (n = 85) or non‐EDDA (n = 53) for at least 6 months.

Interventions. Patients were screened for valvular heart disease by clinical means and by examiner‐blinded echocardiography. Main outcome measure was valvular regurgitation revealed by echocardiography.

Results. Severe aortic regurgitation (n = 4) or moderate aortic (n = 12), mitral (n = 3) or tricuspidal valve regurgitation (n = 5) was found in 22 EDDA patients (25.9%). Two patients had coexistent moderate mitral and tricuspid valvular regurgitation. Two non‐EDDA patients had moderate valve insufficiency (3.8%,P < 0.05). The adjusted relative risk for at least moderate valve insufficiency in the EDDA patients was 7.2% (P < 0.05). The sensitivity of detecting at least moderate valvular disease by cardiac murmur, dyspnoea, or the heart failure marker NT‐proBNP (natriuretic peptide) was 62% for the neurologists and 93% for the cardiologist but with equally low specificity (30–35%).

Conclusion. EDDA was associated with a clinically important and statistically significant risk of at least moderate valve regurgitation. Clinical screening for valve disease was inadequate and it seems advisable to offer EDDA patients control with echocardiography.
Swallowing dysfunction in Wilson’s disease: a scintigraphic study
Authors: Da Silva‐júnior F. P. , Carrasco A. E. A. B. , Da Silva Mendes A. M. , Lopes A. J. T. , Nobre E Souza M. A. , De Bruin V. M. S.
Published: November 2007

Abstract  Although dysphagia is a common complaint of patients with Wilson’s disease (WD) and pneumonia is an important cause of death in these patients, swallowing function remains an underinvestigated field in this condition. The aim of this study was to characterize swallowing dynamics in WD patients. Eight WD patients and 15 age‐matched controls underwent scintigraphic evaluation of oral and pharyngeal deglutition. Patients had significantly slower oral transit (P = 0.008) and a greater percentage of oral residue (P = 0.006) when compared to controls. Two of eight patients were free of neurological symptoms at time of examination. Impaired oropharyngeal function was found in patients without dysphagia and without neurological symptoms. Our findings indicate that WD may present with objective swallowing dysfunction, even in the absence of neurological manifestations. Further studies are necessary to investigate the impact of this dysfunction on morbidity and mortality in WD.
Review of invertebrate biological control agent regulation in Australia, New Zealand, Canada and the USA: recommendations for a harmonized European system
Authors: Hunt E. J. , Kuhlmann U. , Sheppard A. , Qin T.‐K. , Barratt B. I. P. , Harrison L. , Mason P. G. , Parker D. , Flanders R. V. , Goolsby J.
Published: November 2007

Europe lags far behind Australia, New Zealand, Canada and the USA in terms of implementing regulatory procedures for the import and release of invertebrate biological control agents (IBCAs). A number of standards, documents and guidelines have been produced over recent years in an attempt to harmonize regulation of IBCA introduction into Europe. Despite these efforts, the number of member countries implementing any form of IBCA regulation remains low, with many industries, biological practitioners and regulators fearing that a regulatory system would render the process of approval for IBCA introduction into a country costly and time consuming. Europe’s priority is therefore to formulate a regulatory system that will be readily approved of and adopted by all member countries. In this paper we review the current regulatory processes operating in Australia, New Zealand, Canada and the USA. There is potential for Europe to benefit from the years of experience that these countries have in IBCA regulation. We therefore propose recommendations based on features of the regulatory processes in each of the four countries that work well and that could be adopted to generate a workable Europe‐wide regulatory system.
Bring in the Arts and Get the Creativity for Free: A Study of theArtists in ResidenceProject
Authors: Styhre Alexander , Eriksson Michael
Published: November 2007

In the literature on creativity and innovation, there is a tendency to idolize great contributors to the liberal arts as extraordinarily creative individuals. Suchex post factoaccounts of ‘great men and women’ are, however, of limited value for everyday practices in organizations. This paper reports insights from a Swedish project namedArtists in Residence(AIRIS) wherein artists, including musicians, painters, actors and directors, dancers and choreographers, collaborated with a regular company or workplace during a ten‐month project, aimed at helping the co‐workers think in new and creative ways. The study concludes that there are many benefits from making the world of artists and the world of work intersect, but there is also a demand on the participant to fully commit to the project. Even though the culture project was positively received among co‐workers, only a limited effect on workplace climate could be reported for the 2005 evaluation, while the 2006 evaluation indicates more positive effects. Still, the amount of texts advocating artists' creative skills and experiences outnumber the cases of actual projects bringing the two groups together. Studies of projects like AIRIS show that there is a great potential in bringing artists into industry.
Spinal cord degeneration in C57BL/6N mice following induction of experimental parkinsonism with MPTP
Authors: Samantaray Supriti , Knaryan Varduhi H. , Butler Jonathan T. , Ray Swapan K. , Banik Naren L.
Published: November 2007

We examined neurodegeneration in spinal cord (SC) and role of such extra‐nigral degeneration in MPTP‐induced experimental parkinsonism in C57BL/6N mice. HPLC‐photodiode array analysis confirmed presence of the active neurotoxin MPP+in SC after single injection of MPTP (25 mg/kg, i.p.). Mitochondrial enzyme monoamine oxidase‐B (MAO‐B) responsible forin vivoconversion of MPTP to MPP+was inhibited in SC by pre‐treatment withl‐deprenyl, a specific inhibitor of MAO‐B. Besidesin vitroconversion of MPTP to MPP+occurred by SC mitochondrial preparation, which was inhibited byl‐deprenyl implicating SC as a specific target of MPTP‐neurotoxicity. Double immunofluorescent labeling and spectrofluorimetric assay via kynuramine oxidation showed MAO‐B expression and activity in SC neurons. Localization of dopamine transporter immunoreactivity in SC along with specific uptake of3H‐MPP+by SC synaptosomal preparation further confirmed SC as target of MPTP‐neurotoxicity. Compared with control, increased neuronal death on the seventh day in SC of mice injected with MPTP (2 × 25 mg/kg, at 6 h interval) strongly suggested SC degeneration in pre‐symptomatic phase of MPTP‐induced experimental parkinsonism. Such extra‐nigral neurodegeneration in Parkinson’s disease indicated novel molecular mechanism preceding nigrostriatal degeneration and suggested designing broad therapeutic intervention for this complex movement disorder.
Nightjar Caprimulgus europaeus and Woodlark Lullula arborea– recovering species in Britain?
Authors: LANGSTON R. H. W. , WOTTON S. R. , CONWAY G. J. , WRIGHT L. J. , MALLORD J. W. , CURRIE F. A. , DREWITT A. L. , GRICE P. V. , HOCCOM D. G. , SYMES N.
Published: November 2007

The Nightjar Caprimulgus europaeus and Woodlark Lullula arborea are identified as species of conservation concern at both a UK and a European level on account of historical declines in their population sizes and ranges. The UK populations of both species have increased significantly in recent decades and this paper reviews the extent, nature and causes of these population changes, based on evidence from national surveys and autecological studies. It also considers the future prospects of both species in the face of likely changes to their preferred habitats in Britain. Nightjar numbers have increased greatly since the national survey in 1981, when the British population was estimated at only 2100 churring males, with an estimated 3400 in 1992 and 4606 (± 913) in 2004. Population recovery has been closely associated with their colonization of clear‐fell areas in planted forests. Over 57% of the calling (‘churring’) males recorded were in planted forests in 2004. Woodlark numbers have also made a substantial recovery from a low level of just 250 territories in 1986 to 1426–1552 territories in 1997. Over 85% of the Woodlark territories recorded in 1997 were on heathland or in planted forests. Despite these increases, both species continue to occupy only part of their much more extensive former breeding ranges. The recovery of these species has coincided with the availability of suitable open ground habitat resulting from the felling of forests planted in the late 1920s and 1930s, often on former heathland habitats, the clearance and restocking of areas damaged by storms in October 1987 and January 1990 and the restoration of heathland habitats. Forests and heathlands support the majority of the breeding populations of Nightjars and Woodlarks, although there are regional variations in their relative importance. The prospects for further recovery may be limited due to a reduction of open ground habitat following restocking of planted forests, including those damaged in the storms of 1987 and 1990, the effects of recreational disturbance and, at least locally, poor Woodlark breeding productivity due to predation.
The utilization of dead wood resources by woodpeckers in Britain
Authors: SMITH KEN W.
Published: November 2007

Dead wood is important for woodpeckers, providing foraging, roost and nest‐sites. In this paper, data from long‐term studies of woodpeckers and dead wood in oakwoods in southern England are used to examine the dead wood requirements of the three British resident woodpecker species. Both Great Dendrocopos major and Lesser Spotted Woodpeckers Dendrocopos minor select dead trees for nest‐sites although the former is able to nest in living trees too. On the other hand a smaller fraction of Lesser Spotted Woodpecker nests are in living trees. Green Woodpecker Picus viridis shows no selection for dead nesting trees. Hence the smallest woodpecker species appears to be most dependent on dead and decaying trees for nest‐sites. Great and Lesser Spotted Woodpeckers show no preference for foraging on dead trees although they both make use of dead branches on living trees. Lesser Spotted Woodpeckers forage on smaller branches higher in the tree than Great Spotted Woodpeckers. There has been a trend for increasing dead wood resources in the study woods with both dead wood on the ground and standing dead trees (snags) increasing in the last 20 years. The levels of dead wood are shown to be the result of continual processes of creation and decay. Around 0.5% of oak Quercus spp., Ash Fraxinus excelsior and Hornbeam Carpinus betulus and 3.4% of the birch Betula spp. trees die each year in the woods resulting in a continuity of new dead snags and fallen trees. There is a high turnover of standing dead snags of oak and birch with 95% and 80% annual survival, respectively. Snags are only suitable for nesting Great Spotted Woodpeckers for a few years after their creation. It is suggested that these stand and dead wood dynamics are likely to provide habitats more favourable for the Great Spotted than the Lesser Spotted Woodpecker.
Woodland birds in patchy landscapes: the evidence base for strategic networks
Authors: DOLMAN P. M. , HINSLEY S. A. , BELLAMY P. E. , WATTS K.
Published: November 2007

Habitat creation and management within wooded networks is a potentially effective strategy to reduce ecological isolation and the deleterious effects of fragmentation. However, questions remain over the relative advantages of different approaches, e.g. buffering patches vs. increasing connectivity. Potential effects of woodland fragmentation include reduction in regional woodland cover, reduced patch size, edge effects with loss of core habitat, and increased isolation with disruption of dispersal and metapopulation dynamics. We adopt an evidence‐based approach to review how each of these affects woodland birds with an emphasis on studies from the UK and use this to identify management priorities for mitigation. There is evidence for both patch area and composition effects: larger woodlands support more woodland bird species, and woods located within sparsely wooded landscapes are less valuable to specialist woodland species. Bird assemblages show a nested pattern with respect to area, and thus species found in small woods also occur in large woods but not vice versa. However, small woods may be preferred by a few edge species, while small woods also have greater variability in bird species composition. Consideration of the metapopulation dynamics of specialist species with poor dispersal shows that creating or buffering large woodlands is more efficient than a greater total area of small fragments. Connectivity appears most useful for widespread generalist species with almost continuous populations. Woodland structure and quality are of overwhelming importance: as well as mature woodland, young growth, scrub and edges are also key components. There is an urgent need to examine the relationship between nest predation and landscape structure within UK woodlands.
Seed development in Ricinus communis cv. Hale (castor bean). II. Accumulation of phytic acid in the developing endosperm and embryo in relation to the deposition of lipid, protein, and phosphorus
Authors: Greenwood J. S. , Gifford D. J. , Bewley J. D.
Published: November 2007

The accumulation of phytic acid in the developing endosperm and embryo of the castor bean seed (Ricinus communis L. cv. Hale) has been followed in relation to the deposition of the major lipid and protein reserves. In the endosperm, there is a considerable degree of synchronization in the synthesis and deposition of these reserves, although phytic acid accumulation lags behind that of total protein and lipid. The pattern of reserve deposition within the embryo is documented for the first time. Lipid accumulation commences later than in the endosperm, and the major deposition of phytic acid is also later; protein deposition continues longer in the embryo than in the endosperm. Changes in various phosphorus-containing fractions were followed in both the embryo and endosperm during development, viz total, acid-soluble, inorganic, and lipid phosphorus. While sugar and nucleoside phosphates, and then nucleic acid and protein phosphorus, are predominant in the total phosphorus pool earlier in endosperm development, later there is a large increase in the total pool size, which is attributable particularly to phytic acid formation. This component accounts for over 90% of the total phosphorus content of the mature dry endosperm. A similar pattern of events occurs in the developing embryo.
Natural intersectional hybridization between North American species of Populus (Salicaceae) in sections Aigeiros and Tacamahaca. I. Population studies of P. × parryi
Authors: Eckenwalder James E.
Published: November 2007

Populus fremontii and P. trichocarpa are western trees of sections Aigeiros Duby (cottonwoods) and Tacamahaca Spach (balsam poplars), respectively. They have distinctive ranges and ecological tolerances but are broadly sympatric in California and Nevada. Here, the two species often display a narrow zone of overlap between otherwise separate elevational ranges. They may hybridize in such areas to produce the tree that Sargent first named P. × parryi. I have found hybrids in most investigated populations in which both parent species are present. Putative hybrids from four populations are morphologically intermediate between their parents and possess an additive chromatographic profile combining the flavones of cottonwoods with the flavonols of balsam poplars. A pictorialized scatter diagram demonstrates this and morphological and chemical hybrid indices quantify the relationship. Hybrids from two populations, each lacking one of the parent species, resemble hybrids from the other two populations, in which all three taxa are present. Morphological and chemical evidence for advanced-generation hybrids is equivocal. The putative hybrids are less fertile and are more susceptible to at least some pests than are the parent species. These factors may now limit hybridization to the first generation but do not preclude long-term intersectional introgression. Since balsam poplars and cottonwoods have been in contact and have hybridized in this region for at least 12 million years, hybridization may have had significant effects on either or both species as they evolved from their Tertiary ancestors.
An ultrastructural study of particle distribution during microsporogenesis in tomato plants infected with the Brazilian tobacco rattle virus
Authors: Gaspar José O. , Vega J. , Camargo I. J. B. , Costa A. S.
Published: November 2007

Long and short particles of the Brazilian tobacco rattle virus (BTRV) were visualized in cells of the anther tissues of infected tomato plants. The BTRV appeared mostly as aggregates of parallel particles associated with mitochondria, though isolated aggregates and individual particles were seen in microspores and mature pollen grains. The BTRV particles could be seen in the cytoplasm of infected anther cells during the various stages of microsporogenesis from the stage of premeiotic cells to mature pollen grains. Virus distribution through meristems is the main mechanism that permits the BTRV to reach the pollen. Virus passage from somatic cells to the microspore-precursor cells while plasmodesmata are still functional may be complementary in case of early infection or the only way of access in late-infected plants. Both short and long particles could be seen in the cytoplasm of the vegetative and generative cells of the pollen. No virus particle was ever seen in the nuclei of infected cells, associated with the cellulose or callose walls, or on the outside wall of pollen grains. There was a small number of virus particles present in the microspore mother cells and microspores, and a large number of short- and long-particle aggregates in the mature pollen grains. These results indicate that virus increase occurs during pollen grain maturation and is not only the result of distribution. Microsporogenesis is comparable between infected and noninfected tissues. However, pollen grains from infected plants showed a lower germination than normal pollen.
DYONS NEAR THE PLANCK SCALE
Authors: LAPERASHVILI LARISA , DAS C. R.
Published: November 2007

In this paper we suggest a new model of preons–dyons making composite quark–leptons and bosons, described by the supersymmetric string-inspired flipped [Formula: see text] gauge group of symmetry. This approach predicts the possible extension of the Standard Model to the family replicated gauge group model of type GN fam , where N fam is the number of families and G is the symmetry group: G = SMG, SU(5), SO(10), E6, etc. Here E6 and [Formula: see text] are nondual and dual sectors of theory with hyperelectric g and hypermagnetic [Formula: see text] charges, respectively. Starting with an idea that the most realistic model leading to the unification of all fundamental interactions (including gravity) is the "heterotic" string-derived flipped model, we have assumed that at high energies μ > 1016 GeV there exists the following chain of the flipped models: [Formula: see text] ended by the flipped E6 gauge group of symmetry at the scale M SSG ~ 1018 GeV . Suggesting N = 1 supersymmetric [Formula: see text] preonic model we have considered preons as dyons confined by hypermagnetic strings in the region of energies μ≲M Pl . Our model is based on the recent theory of composite non-Abelian flux tubes in SQCD — analog ANO-strings. Considering the breakdown of E6 and [Formula: see text] at the Planck scale into the SU(6) × U(1) gauge group, we have shown that the six types of k-strings — composite N = 1 supersymmetric non-Abelian flux tubes — are created by the condensation of spreons–dyons near the Planck scale and have six fluxes quantized according to the Z6 center group of SU(6): Φn = nΦ0(n = ±1, ±2, ±3). These fluxes give three types of k-strings with tensions Tk = kT0, where k = 1, 2, 3, and produce three (and only three) generations of composite quark–leptons and bosons giving a very specific type of "horizontal symmetry." Thus, the present model predicts N gen = N fam = 3. It was shown that our preonic strings are very thin, with radius R str ~ 10-18 GeV -1, and their tension T0 is enormously large: T0 ~ 1038 GeV 2. It was shown that the condensation of spreons near the Planck scale gives the phase transition at some scales M crit and [Formula: see text], which correspond to the following breakdowns of E6 (or [Formula: see text]) for preons: E6 →SU(6)×U(1), or [Formula: see text]. We have calculated the critical values of gauge coupling constants: α-1(M crit ) ≈4.23 and [Formula: see text]. It was investigated that in our world we have quark–leptons and gauge bosons Aμ in the region of energies μ≲M Pl , but monopolic "quark–leptons" and dual gauge fields [Formula: see text] exist in the region μ≳M Pl .
${\mathcal N}=1^*$ MODEL SUPERPOTENTIAL REVISITED (IR BEHAVIOR OF ${\mathcal N}=4$ LIMIT)
Authors: ARNONE S. , DI SEGNI G. , SICCARDI M. , YOSHIDA K.
Published: November 2007

The one-loop contribution to the superpotential, in particular the Veneziano–Yankielowicz potential in [Formula: see text] supersymmetric Yang–Mills model is discussed from an elementary field theory method and the matrix model point of view. Both approaches are based on the renormalization group variation of the superconformal [Formula: see text] supersymmetric Yang–Mills model.
On camelback: René Chudeau (1864–1921), Conrad Kilian (1898–1950), Albert Félix de Lapparent (1905–1975) and Théodore Monod (1902–2000), four French geological travellers cross the Sahara
Authors: Taquet Philippe
Published: November 2007

From 1920 to 1990, these brave geologists travelled through the Sahara from Mauritania to Libya and from Algeria to Niger. During these hikes across thousands of kilometres, often in very difficult conditions, they were able to trace the main features of the geology of these desert regions, they established stratigraphical sections of the main sedimentary provinces, discovered volcanic and eruptive complexes and drew geological maps of large areas.

Today, helicopters, four-wheel-drive vehicles, satellite observations and global positioning systems allow people to visit the most remote regions of the Sahara safely; however, geologists, naturalists and explorers like Chudeau, Kilian, De Lapparent, Monod made the most of their observations and discoveries thanks two essential auxiliaries: the camel and the goatskin bottle.

The portraits and the principal contributions to the geology of the Sahara of these four pioneers are presented here with maps of their itineraries.
The organized traveller: scientific instructions for geological travels in Italy and Europe during the eighteenth and nineteenth centuries
Authors: Vaccari E.
Published: November 2007

The history of geological travels usually focuses on the study of individuals or groups of travellers, but it should also consider in detail some essential aspects of the meaning of geological travel, such as the beginnings of this particular kind of scientific travel, the emergence of a ‘conscious’ geological traveller, the concept of ‘field’ and fieldwork for a geologist and finally the first attempts to codify the style and the method of a geological travel. The aim of this paper is to look at possible answers to some of these questions by presenting a short outline, based on some significant examples in the historical development of a particular kind of scientific literature still little known and open to further investigation: the instructions for geological travellers, including writing by those people, generally scientists, who wanted to organize their experiences to instruct others on how to undertake geological observations methodically. From the early eighteenth century, these texts may be found within private diaries or official reports, in journals or periodicals, scholarly monographs or textbooks, and also as articles, pamphlets, booklets or even books on their own, especially in the late nineteenth century.