julilili42/papers huggingface dataset:
Applicability of ground‐penetrating radar as a tool for nondestructive soil‐depth mapping on Pleistocene periglacial slope deposits
2009-06-16

Abstract Soil depth plays a decisive role in determining soil properties in mountainous regions for ecological site assessment. To evaluate the use of ground‐penetrating radar (GPR) for fast and high‐resolution mapping within mountainous regions, we examined the possibilities and limitations of GPR to determine soil depth over bedrock and to delineate individual substrate layers formed during the Pleistocene in a periglacial environment (Pleistocene periglacial slope deposits, PPSD). Selected catenae in representative subregions of the study area (Dill catchment, SE Rhenish Massif, Germany) have been successfully mapped using GPR. A practicable method was developed using a 400 MHz antenna to reach a mean penetration depth of 1.5 m and to map different substrates and layers of PPSD based on calibrations of the GPR at soil pits along 12 catenae. Colluvium, the three types of PPSD layers, as well as the in situ bedrock could be distinguished in most sections of the GPR surveys. Characteristic GPR facies caused by intrinsic material properties of the different substrates, such as stone content and soil moisture content, could be distinguished in different geomorphologic and lithological settings. A layer‐based velocity distribution was determined for characteristic substrate layers at soil pits enabling us to considerably enhance the accuracy of soil‐depth prediction. Compared to traditionally surveyed soil profiles, our results demonstrate an accuracy of layer thickness surveying within a standard deviation of approx. 0.1 m. It is demonstrated that the combination of GPR with conventional soil‐pit mapping is an efficient and valid method to produce high‐resolution data of substrate distribution.
Microstructural Evolution of Silica on Single Crystal Silicon Carbide. Part II: Influence of Impurities and Defects
2009-06-16

Passive oxidation of single crystal silicon carbide (6H–SiC) resulted in the formation of a vitreous silica layer which crystallized gradually at temperatures near 1300°–1400°C. During this process, statistically distributed devitrification centers appeared and disk‐like aligned crystal plates (radialites) formed. The crystallization process did not necessarily start at structural defects although these often act as areas of preferred nucleation. A second structural transition from disk‐like radialites to small crystalline spheres (globulites) was not connected to structural defects but a consequence of the presence of impurities. Alkaline and earth‐alkaline elements are common contaminations within the atmospheres of typical furnaces fitted with alumina tubes. Globulite formation was a process of recrystallization catalyzed by an impurity‐related melt formed on top of the devitrified areas. Crystallization caused exsolution of reaction gas and local impurity enrichments as the solubility for these phases is much higher in the devitrifying vitreous silica matrix. Both clean and impurity‐loaded oxidation produced specific morphologies of scales and interfaces.
Why do shrews twitter? Communication or simple echo-based orientation
2009-06-17

Shrews are very vocal animals. We tested behaviourally whether the high-pitched laryngeal ‘twittering’ calls of as-yet unclear function serve for communication or echo-based orientation. We used a representative species from each of the two largest phylogenetic groups of shrews. In both species, experimental manipulation of substrate density, but not of the likelihood of conspecific presence, affected the shrews' call rate when exploring an unknown environment. This adaptation of call rate to the degree of habitat clutter parallels bat echolocation and suggests that shrews may use the echoes and reverberations of their calls for identifying routes through their habitat or for probing habitat type. To assess the acoustic feasibility of shrew echo orientation, we ensonified shrew habitats in the field with an ‘artificial shrew’ (small speaker mounted close to a sensitive microphone). The data showed that shrew-like calls can indeed yield echo scenes useful for habitat assessment at close range, but beyond the range of the shrews' vibrissae.
Orientation and electronic properties of phthalocyanines on polycrystalline substrates
2009-06-18

Abstract We review the molecular orientation of phthalocyanines as representatives of flat, π‐conjugated molecules on different polycrystalline substrates. Thin films with a thickness of ∼10–50 nm are often highly ordered on several substrates. The molecular orientation, however, can be radically different for single crystalline model substrates and for relatively ill defined polycrystalline substrates. Moreover, it is important to distinguish between the growth of the first organic layer(s) at the substrate surface and the growth in films of a thickness of several nanometers: Differently oriented, buried interfacial layers of few monolayers were observed in particular for polycrystalline substrates. The growth mode is discussed in terms of different molecule–molecule and molecule–substrate interactions. Consequences for our understanding of the behavior of such films in devices are considered in context with electronic interface properties. (© 2009 WILEY‐VCH Verlag GmbH &amp; Co. KGaA, Weinheim)
Single‐cell expression profiling of dopaminergic neurons combined with association analysis identifies pyridoxal kinase as Parkinson's disease gene
2009-06-18

Abstract Objective The etiology of Parkinson disease (PD) is complex and multifactorial, with hereditary and environmental factors contributing. Monogenic forms have provided molecular clues to disease mechanisms but genetic modifiers of idiopathic PD are still to be determined. Methods We carried out whole‐genome expression profiling of isolated human substantia nigra (SN) neurons from patients with PD vs. controls followed by association analysis of tagging single‐nucleotide polymorphisms (SNPs) in differentially regulated genes. Association was investigated in a German PD sample and confirmed in Italian and British cohorts. Results We identified four differentially expressed genes located in PD candidate pathways, ie, MTND2 (mitochondrial, p = 7.14 × 10 −7 ), PDXK (vitamin B6/dopamine metabolism, p = 3.27 × 10 −6 ), SRGAP3 (axon guidance, p = 5.65 × 10 −6 ), and TRAPPC4 (vesicle transport, p = 5.81 × 10 −6 ). We identified a DNA variant ( rs2010795 ) in PDXK associated with an increased risk of PD in the German cohort ( p = 0.00032). This association was confirmed in the British ( p = 0.028) and Italian ( p = 0.0025) cohorts individually and reached a combined value of p = 1.2 × 10 −7 (odds ratio [OR], 1.3; 95% confidence interval [CI], 1.18–1.44). Interpretation We provide an example of how microgenomic genome‐wide expression studies in combination with association analysis can aid to identify genetic modifiers in neurodegenerative disorders. The detection of a genetic variant in PDXK , together with evidence accumulating from clinical studies, emphasize the impact of vitamin B6 status and metabolism on disease risk and therapy in PD. Ann Neurol 2009;66:792–798
Corrigendum to “Antithrombotic therapy after bioprosthetic aortic valve replacement: ACTION Registry survey results” [Eur. J. Cardiothorac. Surg. 33 (2008) 531–536]
2009-06-18

Department of Cardiovascular Surgery, Hospital Clinic, Barcelona, Spain Department of Cardio-Vascular and Thoracic Surgery, University of Rennes, France Department of Cardiothoracic Surgery, St. Antonius Hospital, Nieuwegein, The Netherlands Department of Cardiac and Thoracic Surgery, University of Cologne, Germany Department of Cardiac Surgery, The Royal Sussex County Hospital, United Kingdom Department of Cardiothoracic Surgery, University Hospital Birmingham, United Kingdom Department of Cardiothoracic Surgery, University Hospital, Coimbra, Portugal Department of Thoracic and Cardiovascular Surgery, Heart Center North Rhine-Westphalia, Ruhr University of Bochum, Bad Oeynhausen, Germany Department of Cardiothoracic Surgery, Wessex Cardiothoracic Centre, Southampton General Hospital, Southampton, United Kingdom Department of Thoracic, Cardiac and Vascular Surgery, University of Tubingen, Germany Department of Cardiovascular Surgery, Pitie Salpetriere Hospital, University Pierre et Marie Curie, France Department of Cardio-Thoracic Surgery, Catharina Hospital, Eindhoven, The Netherlands Department of Cardiac Surgery, University of Parma, Italy
Effects of Humic Substances and Quinones at Low Concentrations on Ferrihydrite Reduction by Geobacter metallireducens
2009-06-19

Humic substances (HS) and quinones can accelerate dissimilatory Fe(III) reduction by electron shuttling between microorganisms and poorly soluble iron(III) (hydr)oxides. The mechanism of electron shuttling for HS is not fully understood, but it is suggested that the most important redox-active components in HS are also quinones. Here we studied the influence of HS and different quinones at low concentrations on ferrihydrite reduction by Geobacter metallireducens. The aquatic HS used were humic and fulvic acids (HA and FA) isolated from groundwater of a deep aquifer in Gorleben (Niedersachsen, Germany). HA stimulated iron reduction stronger than FA down to total HA concentrations as low as 1 mg/L. The quinones studied showed large differences: some had strong accelerating effects, whereas others showed only small effects, no effects, or even inhibitory effects on the kinetics of iron reduction. We found that the redox potentials of the most active quinones fall in a narrow range of -137 to -225 mV vs NHE at pH 7. These results give evidence that the kinetic of microbial iron reduction mediated by electron shuttles is mainly controlled by thermodynamic parameters, i.e., by the redox potential of the shuttle compound, rather than by the proportion of dissolved vs adsorbed compound.
ChemInform Abstract: Biosynthetic Capacities of Actinomycetes. Part 49. Albidopyrone (I), a New α‐Pyrone‐Containing Metabolite from Marine‐Derived Streptomyces sp. NTK 227
2009-06-19

Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
3-(4-Fluorophenyl)-6-methoxy-2-(4-pyridyl)quinoxaline
2009-06-19

In the title compound, C(20)H(14)FN(3)O, the quinoxaline system makes dihedral angles of 32.38 (7) and 48.04 (7)° with the 4-fluoro-phenyl and pyridine rings, respectively. The 4-fluoro-phenyl ring makes a dihedral angle of 57.77 (9)° with the pyridine ring. In the crystal, the mol-ecules form dimeric C-H⋯N hydrogen-bonded R(2) (2)(20) ring motifs lying about crystallographic inversion centers. The dimeric units stack via π-π inter-actions between methoxy-phenyl rings and pyridine-fluoro-phenyl rings with centroid-centroid distances of 3.720 (1) and 3.823 (1) Å, respectively. The respective average perpendicular distances are 3.421 and 3.378 Å, with dihedral angles between the rings of 1.31 (9) and 11.64 (9)°.
Using wikis for organizational learning: functional and psycho‐social principles
2009-06-20

Purpose The purpose of this paper is to aim to identify principles that make wikis an effective application when they are used within an organization. Those principles are supposed to make wikis a successful instrument for organizational learning. Design/methodology/approach The article makes a distinction between functional and psycho‐social principles and emphasizes their impact on organizational learning. Findings The functional principles (quick and easy editing; wikilinks; no hierarchical hypertext structure; revision and topicality; collaborative product; scalability and flexibility) may be regarded as the constitutive attributes of wikis. The psycho‐social principles (openness; self‐organization; autonomy; interest and personal relevance; diversity; serendipity effect) are not directly associated with wikis as a tool, but refer to the application context. Originality/value The article explains the functional and psycho‐social principles in detail. This will help organizations and knowledge‐management executives to employ wikis in an efficient way and avoid their disadvantages. Thus, the functional and psycho‐social principles can be a valuable starting point for applying wikis successfully in various organizational scenarios.
Cerebellar Engagement in an Action Observation Network
2009-06-22

The cerebellum has traditionally been viewed as a brain structure subserving skilled motor behaviors. However, the cerebellum might be involved not only in movement coordination, but also in action observation and understanding of others' actions. Veridical visual perception of human body motion is of immense importance for a variety of daily-life situations and for successful social interactions. Here, by combining visual psychophysics with a lesion analysis, we assessed visual sensitivity to human walking in patients with lesions to the left cerebellum. Patients with left lateral cerebellar lesions exhibit deficits in visual sensitivity to body motion, whereas medial lesions do not substantially affect visual perception of human locomotion. The findings point to left lateral cerebellar involvement in an action observation network. We discuss possible mechanisms of cerebellar engagement in visual social perception revealed by body motion.
Relative resistance of SGK1 knockout mice against chemical carcinogenesis
2009-06-22

Abstract The serum and glucocorticoid inducible kinase SGK1 was originally cloned from mammary tumor cells. SGK1 was found to be up‐regulated in a variety of tumors, but down‐regulated in several distinct tumors. Thus, evidence for a role of SGK1 in tumor growth remained conflicting. According to in vitro observations, SGK1 is up‐regulated by the oncogene β‐catenin and negatively regulates the proapoptotic transcription factor FOXO3a, which in turn stimulates transcription of the Bcl2‐interacting mediator BIM. This study aimed to define the role of SGK1 in colon carcinoma in vivo . SGK1 knockout mice ( sgk1 −/− ) and their wild type littermates ( sgk1 +/+ ) were subjected to chemical cancerogenesis (intraperitoneal injection of 20 mg/kg 1,2‐dimethylhydrazine followed by three cycles of 30 g/L synthetic dextran sulfate sodium for 7 days). Moreover, SGK1 was silenced in HEK293 cells. FOXO3a and BIM protein abundance was determined by Western blotting and immunohistochemistry. Following chemical cancerogenesis, sgk1 −/− mice developed significantly less colonic tumors than sgk1 +/+ mice. According to Western blotting and immunohistochemistry, SGK1 deficiency enhanced the expression of FOXO3a and BIM both, in vitro and in vivo . SGK1 deficiency counteracts the development of colonic tumors, an effect at least in part due to up‐regulation of FOXO3a and BIM. © 2009 IUBMB IUBMB Life, 61(7): 768–776, 2009
Morpho‐tectonic evolution of the Crimean mountains (Ukraine) as constrained by apatite fission track data
2009-06-22

Abstract Apatite fission track thermochronology (AFT) is used to investigate the low‐temperature thermal evolution of the Crimean Mountains and provide new insights into the geodynamic and geomorphic evolution of the westernmost tip of the Caucasus–Crimean fold‐and‐thrust belt. The vast majority of the samples taken from Jurassic sedimentary and magmatic rocks revealed AFT ages in the range of 51–32 Ma. These ages, together with modelled cooling paths, show that the mountain range experienced a thermal overprint after the Late Cimmerian orogeny. We interpret the overprint in terms of the burial of Cimmerian structures by a thick pile (&gt;4 km) of platform sediments during Early Cretaceous–Late Eocene times. This scenario implies that highly elevated palaeosurfaces of Early Cretaceous age survived in large part because of the protection provided by thick accumulations of platform deposits. Since final uplift in the middle Pliocene, the palaeosurfaces have been significantly degraded and dissected by fluvial incision and large‐scale landslides.
Influence of standard treatment on ileal and colonic antimicrobial defensin expression in active Crohn’s disease
2009-06-22

Summary Background Crohn’s Disease (CD), a chronic intestinal inflammation, is currently treated primarily by therapeutics which are directed against inflammatory responses. Recent findings though suggest a central role of the innate immune barrier in the pathophysiology. Important factors providing this barrier are antimicrobial peptides like the α‐ and β‐defensins. Little is known about in vivo effects of common drugs on their expression. Aim To analyse the influence of corticosteroids, azathioprine and aminosalicylate treatment on ileal and colonic antimicrobial peptides in active CD and also assess the role of inflammation. Methods We measured the expression of antimicrobial peptides and pro‐inflammatory cytokines in 75 patients with active CD. Results Ileal and colonic α‐ and β‐defensins as well as LL37 remained unaffected by corticosteroids, azathioprine or aminosalicylate treatment. Additionally, we did not observe a negative coherency between Paneth cell α‐defensins and any measured cytokines. HBD2 and LL37 unlike HBD1 levels were linked to inflammatory cytokines and increased in highly inflamed samples. Conclusions Current oral drug treatment seems to have no major effect on the expression of antimicrobial peptides. In contrast to HBD2 and LL37, ileal levels of HD5 and HD6 and colonic HBD1 level are independent of current inflammation. Innovative drugs should aim to strengthen protective innate immunity.
Tryptophan is a marker of human postmortem brain tissue quality
2009-06-22

Abstract Postmortem human brain tissue is widely used in neuroscience research, but use of tissue originating from different brain bank centers is considered inaccurate because of possible heterogeneity in sample quality. There is thus a need for well‐characterized markers to assess the quality of postmortem brain tissue. Toward this aim, we determined tryptophan (TRP) concentrations, phosphofructokinase‐1 and glutamate decarboxylase activities in 119 brain tissue samples. These neurochemical parameters were tested in samples from autopsied individuals, including control and pathological cases provided by 10 different brain bank centers. Parameters were assessed for correlation with agonal state, postmortem interval, age and gender, brain region, preservation and freezing methods, storage conditions and storage time, RNA integrity, and tissue pH value. TRP concentrations were elevated significantly ( p = 0.045) with increased postmortem interval; which might indicate increased protein degradation. Therefore, TRP concentration might be one useful and convenient marker for estimating the quality of human postmortem brain tissue.
Loop closure and trajectory estimation with long-range passive RFID in densely tagged environments
2009-06-22

In more and more commercial scenarios, radio frequency identification (RFID) is used to tag assets on a large scale. These given tag infrastructures offer themselves for the navigation of autonomous transport vehicles and service robots. In this paper we investigate loop closure for graphbased simultaneous localization and mapping (SLAM) and trajectory estimation in environments with such dense RFID infrastructures: We compare different methods of inferring that a place has been revisited, examine their robustness, and show how the trajectory of the robot can be reconstructed. Given this trajectory, a robot is able to map transponder positions or to localize itself with RFID and odometry alone and without a reference localization system. The accuracy of our approach is shown through a series of experiments with a mobile robot.
They Do What They Are Told to Do: The Influence of Instruction on (Chess) Expert Perception—Commentary on Linhares and Brum (2007)
2009-06-22

Abstract Linhares and Brum (2007) argue that they provide evidence for analogy as the main principle behind experts’ acquisition of perceptual knowledge. However, the methodology they used—asking players to pair positions using abstract similarity—raises the possibility that the task reflects more the effect of directional instructions than the principles underlying the acquisition of knowledge. Here we replicate and extend Linhares and Brum’s experiment and show that the matching task they used is inadequate for drawing any conclusions about the nature of experts’ perception. When expert chess players were instructed to match problems based on similarities at the abstract level (analogy), they produced more abstract pairs than pairs based on concrete similarity. However, the same experts produced more concrete pairs than abstract ones when instructed to match the problems based on concrete similarity. Asking experts to match problems using explicit instructions is not an appropriate way to show the importance of either analogy or similarity in the acquisition of expert knowledge. Experts simply do what they are told to do.
SHOULDERED ADZES, BIFACES, AND CHERT PRISMS: A CHARACTERIZATION OF MIMOTIEN STONE TOOL ASSEMBLAGES FROM LATER CAMBODIAN PREHISTORY
2009-06-22

Mimotien circular earthworks in the red soil area of east Cambodia and southern Vietnam (Anonymous 1930; Malleret 1959; Groslier 1966 a, b) are dated to the end of the Neolithic and the beginning of the Metal Age with the settlements ending in the second half of the first millennium BC (Haidle 2001). Fifty-six of these very homogeneous settlement sites with outer wall, inner ditch and central platform have been recorded so far (Nguyen 1984, 1997, 1999; Luong 1985; Nguyen 1986; Kojo and Pheng 1997; Dega 2002; Thuy 2002; Haidle 2006), of which Krek 52/62, in Ponhea Krek district, Kampong Cham province, Cambodia, is the most intensively examined (Dega et al. 1997; Kojo and Peng 1998; Albrecht et al. 2000; Vin 2003). A total area of 100 m2 has been excavated there between 1997 and 2004 by a GermanCambodian team from Tubingen University, Royal University of Fine Arts Phnom Penh and Memot Centre for Archaeology. Artefacts are concentrated on the edge of the inner platform. These include pottery, spindle whorls and other ceramic artefacts (Heng and Som 1999; Haidle et al. submitted) as well as fragments of glass bangles (Haidle 2001; Haidle and Neumann 2004) and an abundance of lithic artefacts. Some hundred stone tools in different stages of their artefact life, from blanks to finally discarded pieces, have been discovered together with debris from production and reworking. The lithic inventories of this (Heng and Mao 1999) and other Mimotien earthworks (Chhor et al. 1999; Thuy 1999; Dega 2002) present a diverse picture of raw materials (Neumann and Haidle 2002), tool types, production modes, and functions.
Direct crosstalk between mast cell–TNF and TNFR1-expressing endothelia mediates local tissue inflammation
2009-06-23

Abstract Signaling through tumor necrosis factor receptor 1 (TNFR1) controls bacterial infections and the induction of inflammatory Th1 cell–mediated autoimmune diseases. By dissecting Th1 cell–mediated delayed-type hypersensitivity responses (DTHRs) into single steps, we localized a central defect to the missing TNFR1 expression by endothelial cells (ECs). Adoptive transfer and mast cell knockin experiments into KitW/KitW-v, TNF−/−, and TNFR1−/− mice showed that the signaling defect exclusively affects mast cell–EC interactions but not T cells or antigen-presenting cells. As a consequence, TNFR1−/− mice had strongly reduced mRNA and protein expression of P-selectin, E-selectin, ICAM-1, and VCAM-1 during DTHR elicitation. In consequence, intravital fluorescence microscopy revealed up to 80% reduction of leukocyte rolling and firm adhesion in TNFR1−/− mice. As substitution of TNF−/− mice with TNF-producing mast cells fully restored DTHR in these mice, signaling of mast cell-derived TNF through TNFR1-expressing ECs is essential for the recruitment of leukocytes into sites of inflammation.