bluuebunny/crossref_metadata_2025_split huggingface dataset:
Cryoturbations: A sediment structural analysis
Authors: Vandenberghe J. 
Published: February 2007

AbstractCryoturbations have always provoked discussions on their origin. However, the sedimentary structures which result from the deformations differ according to the mechanism involved. Diagnostic characterization by sedimentary structure is especially suited to distinguish between deformations caused by cryohydrostatic and cryostatic pressure on the one hand and by periglacial loading on the other.
Present‐day periglacial microforms in the Lesotho Highlands: Implications for present and past climatic conditions
Authors: Hanvey Patricia M. , Marker Margaret E 
Published: February 2007

AbstractA variety of active periglacial microforms have been identified in the vicinity of Tlaeeng Pass (3275 m a.s.l.) in the Lesotho Highlands. These include thufa (both earth and stone‐cored varieties), terracettes, stone polygons and patterned ground. Ground ice within the saturated zone of soil profiles is clearly evident during the winter season, and pebbles perched on needle ice up to 5 cm in length are common. Although possible relict periglacial landforms (such as nivation hollows and protalus ramparts) have been recorded in the area, their identification and, hence, associated climatic inferences is problematic.The presence of active features clearly indicates present‐day periglacial activity, with the variety of forms resulting from diurnal or seasonal freeze‐thaw cycles. Considering a widely accepted global decrease in temperature during the Quaternary, a severity of temperatures greater than what is experienced under present marginal periglacial conditions can be projected for the Lesotho Highlands. However, past moisture regimes are more difficult to project from present‐day features, and this problem is exacerbated by the general paucity of clearly defined diagnostic relict forms.
Variations Dilatométriques de Cylindres de Roches Calcaires Subissant des Cycles de Gel‐Dégel
Authors: Prick A. , Pissart A. , Ozouf J.‐C. 
Published: February 2007

AbstractLes variations de diamétre et de longueur de cylindres de roches calcaires poreuses ont été mesurées au cours de cycles de gel‐dégel. Il est apparu ainsi l'existence de variations de dimension de ces roches, fort complexes et non isotropiques. Ces variations résultent essentiellement de la migration d'eau non gelée au sein des échantillons; ces migrations, dirigées vers les pores le plus larges ou vers les faces des échantillons exposées d'abord au front de gel, produisent des contractions là où des dilatations auraient été attendues. Les expériences soulignent toute l'importance du degré d'humidité des échantillons, de la porosité de la roche, de la vitesse de gel et de faibles variations éventuelles des dispositifs expérimentaux utilisés. Ces mesures dilatométriques donnent pour les variations de longueur des échantillons, des indications précieuses sur les tensions que subissent les roches sous l'action du gel et paraissent ětre une méthode d'étude prometteuse de la gélivation.
Changes in the extent of permafrost during the late quaternary period in the territory of the former Soviet Union
Authors: Kondratjeva Kalerija A. , Khrutzky Stanislav F. , Romanovsky Nikolai N. 
Published: February 2007

AbstractThe cryolithozone occupies a considerable part of the territory of the former Soviet Union. During the Zyriansk (50,000–60,000 years BP) and Sartansk (15,000–27,000 years BP) cold periods of the late Pleistocene, permafrost developed to its maximum thickness and spread as far south as 48–49°N on the Russian plain. In western Siberia and the European north‐east, relict Pleistocene permafrost is separated at depth from late Pleistocene permafrost by a thaw layer; in middle and eastern Siberia where no ice sheets developed, the permafrost is continuous and thick. During the late Glacial to early Holocene warming, the extent of the cryolithozone diminished and thermokarst processes intensified. Using geothermal data from deep boreholes, the approximate rock palaeotemperatures for the last 12,000 years are described for the Russian plain, western Siberia and eastern Siberia.
Talus movement in the high equatorial andes: A synthesis of ten years of data
Authors: Pérez Francisco L. 
Published: February 2007

AbstractThe surficial movement of debris was monitored on a talus cone in the Venezuelan Andes for about a decade. The talus surface was classified into three textures (blocks, pebbles, sand). Painted stones were placed along four transects perpendicular to the slope; many markers (≈︁ 36%) were lost, mostly in pebble and sand areas, owing to burial. Mean stone movement decreased downslope, being much lower on the talus base (33.8 cm) than on the lines above (157.9, 239.9 and 107.8 cm). Tracers on blocks shifted a shorter distance (36.9 cm) than those on either pebbles (152.3 cm) or sand (225.1 cm). A regression showed that annual movement rates on 46 plots were inversely correlated with mean particle size (r=−0.878). An ANOVA indicated that the difference in rates between textures was more significant than that found between slope positions. Markers below outcrops also moved less than those on open talus. A line painted on the rockwall at the talus apex showed alternate periods of debris erosion and accretion, with an overall drop of 22.2 mm of the talus surface during a period of 11.5 years. Rates of debris movement vary substantially between talus textures because these are affected by different transport processes. Mean rates of debris movement remained essentially erratic during the study period, showing no consistent trends through time.
Present and past geocryogenic processes in Mexico
Authors: Heine Klaus 
Published: February 2007

AbstractPeriglacial processes and landforms are described from the Cordillera Neovolcánica of central Mexico. Inactive rock glaciers are related to different late‐glacial and Holocene phases of permafrost conditions. Active discontinuous permafrost occurs above c. 4600 m ASL and appears to be from the Little Ice Age. The lower limit of late‐glacial rock glaciers is situated 500 and 600 m lower than during the Little Ice Age.
Quantitative estimation of cryogenic weathering energy
Authors: Vasiliyev A. A. 
Published: February 2007

AbstractExperiments to measure the energy released by the cryogenic weathering of sandstone and shale are described. The energy released by fracturing is thought to be proportional to the importance of new surfaces appearing in the rock at the time of disintegration. The specific surfaces of samples which have been submitted to freezing have been determined by an absorption technique. The energy released by disintegration of sandstone is about −400 Kj/m2 of specific surface, and for shale is 700 Kj/m2. These values represent less than 1–2% of the heat flux of the frozen rock and have a negligible effect therefore, on the thermal region of the active layer.
Some observations regarding sorted stripes, livingston island, south shetlands
Authors: Hall Kevin 
Published: February 2007

AbstractSorted stripes have long been recognized in the sub‐Antarctic and the maritime Antarctic. The cold and wet conditions of these regions, when compared with the drier continent, are ideal for their development. In particular, the frequent low‐amplitude, short‐duration freeze‐thaw cycles of the sub‐Antarctic favour the development of miniature sorted forms. The maritime Antarctic, however, with its larger amplitude and longer duration of freeze‐thaw cycles, plus the presence of permafrost, exhibits a more frequent occurrence of the larger forms.The Byers Peninsula has an extensive range of sorted features but, despite being situated in the maritime Antarctic and within a permafrost zone, the majority of these features are of the miniature variety. In addition, the sorted stripes exhibit a distinct spatial preference. Their alignment and spatial distribution are not associated with either the sun or the wind, but are a function of the snow cover.
Water migration and ice segregation in the transition zone between thawed and frozen soil
Authors: Solomatin V. I. , Xu Xiaozu 
Published: February 2007

AbstractSamples of silty clay were kept under constant boundary temperature conditions of +1°C (top) and −1°C (bottom) in a series of cold room laboratory experiments. Water migration and ice enrichment near the permafrost table were observed in all samples. Cryogenic layering was observed in soil layers with boundary temperature conditions of −0.5 to −1.0°C. These results confirm earlier observations which explain the occurrence of an ice‐rich layer near the permafrost table, and they may be used to explain the influence of snow cover on isotopic composition of near‐surface ground water and ice.
Ground temperature and related permafrost characteristics in west greenland
Authors: Van Tatenhove Frank G. M. , Olesen Ole B. 
Published: February 2007

AbstractShallow and surficial ground temperatures in west Greenland are presented and reviewed together with available deep temperature profiles in the unglaciated area of west and southwest Greenland. Ground temperature measurements in Kangerlussuaq (Søndre Strømfjord) reveal a temperature at the depth of zero annual amplitude, TZAA, of −1.6 ± 0.2°C. The average thickness of the active layer is 1.7 m and the permafrost thickness is estimated to be 127 ± 31 m. The permafrost thickness in Sisimiut (Holsteinborg) is estimated to be 33 ± 9m with TZAA at −0.3 ± 0.1°C. In Sisimiut, the average active layer thickness is 2.3 m. Between Kangerlussuaq and the ice sheet margin, permafrost is continuous and the active layer thickness is between 0.15 and 5.0m. The interactions between geomorphology, wind pattern, snowcover characteristics and paths of snow meltwater play an important role in determining the variability in ground temperature and permafrost thickness over short distances. The distribution and redistribution of available water are especially important in the low‐precipitation area near the ice margin in central west Greenland. Therefore soil temperatures tend to be colder in low‐lying, organic‐rich soils with dense vegetation than in sandy, inorganic soils with discontinuous vegetation. Within a west Greenland perspective, ground temperature in Sisimiut is relatively warm and in Kangerlussuaq relatively cold owing to their respectively more oceanic and continental climatic regimes.
Active patterned ground and cryoturbation on Muckish mountain, Co. Donegal, Ireland
Authors: Wilson Peter , Sellier Dominique 
Published: February 2007

AbstractActive stony earth circles occur on the less coarse cells of relict sorted nets developed in quartzite debris above 600m ASL on Muckish Mountain, north‐west Ireland. The earth circles are underlain by deformed and truncated podzolic soil horizons that resemble cryoturbations produced by differential frost heave of adjacent sediments. Grain‐size distributions indicate that the soils are frost‐susceptible and possess negative frost‐susceptibility gradients. This infrequent association of coarse quartzite debris and fine‐grained frost‐susceptible matrix probably arises from the weathering of thin inter‐bedded pelites (schists) within the quartzite. Recent activity may have been triggered by climatic deterioration during the Little Ice Age, although present climate on Muckish appears capable of maintaining the surface morphology of the stony earth circles. These features, along with forms described previously, suggest that most if not all upland areas in Ireland above 600‐700m ASL possess climatic conditions favouring frost‐related soil processes.
Grèzes, grèzes litées: Historique des définitions
Authors: Ozouf J.‐C. , Coutard J.‐P. , Lautridou J.‐P. 
Published: February 2007

AbstractThe terms grèze and grèze litée, introduced by Y. Guillien to define a special type of slope deposit, are often not well used by authors. It is necessary to recall the initial definitions. The grèze is a sandy and gravelly material produced by frost shattering: mode 2.5 mm, maximum size 25 mm. The use of the term éboulis ordonnés as a synonym for grèze litée should be avoided because this type of deposit accumulates by solifluction and runoff processes, not by successive rockfalls.
Processus Génétiques à l'origine des Formations de Pente à Graviers de Craie en Champagne
Authors: Laurain M. , Guérin H. , Marre A. , Richard Et J. 
Published: February 2007

AbstractEn Champagne, des dépts de pente stratifiés crayeux connus sous le nom de ‘graveluche’ sont nombreux. Ils sont formés de dèbris calcaire dont la taille varie de 2 à 3 mm jusqu'à 1 à 2 cm et d'une matrice silteuse. Des lits gras alternent avec des lits maigres. Trois explications différentes ont été proposées pour en expliquer la genèse; il s'agirait soit: 1) de depots éoliens, 2) de dépǒts de solifluxion, 3) de dépǒts résultant d'écoulements gravitaires mal précisés.
Models for the genetic and environmental interpretation of stratified slope deposits: Review
Authors: van Steijn Henk , Bertran Pascal , Francou Bernard , Texier Jean‐Pierre , Hétu Bernard 
Published: February 2007

AbstractThe principal aspects addressed are the relationships between transport processes and de‐positional environments, and the sedimentary properties of the deposits. The following ‘process‐product’ models are discussed: (a) stone‐banked solifluction sheets or lobes, (b) dry grain flows and frost‐coated clast flows, (c) debris flows, and (d) niveo‐aeolian transport within the context of talus development. Problems of convergence, the possible role of other processes, and the climatic significance of stratified slope deposits are briefly discussed.
Quelques Considérations Concernant des Formations de Pente dans les Carpates Méridionales
Authors: Urdea Petru 
Published: February 2007

AbstractEn Roumanie les formations de pente des Carpates Méridionales sont peu étudiées. Le présent article est consacré aux formations de pente des zones alpine et forestière des montagnes Fgraş, Retezat et Cǎndrel. Des analyses morphographiques, morphométriques, granulométriques et minéralogiques mettent en évidence les particularités de ces formations. Celles‐ci indiquent les processus génétiques permettant de différencier éboulis de gravité, éboulis à avalanches, bourrelets‐protalus, éboulis fluants, éboulis ruisselés, cǒnes et talus d'avalanches, éboulis soliflués et dépǒts de solifluxion. Ces formes sont présentes surtout dans les régions alpines formées de schistes cristallins et largement développées dans les montagnes de Fǎgǎraş, et Cǎndrel. L'analyse minutieuse des éboulis stratifiés, et leurs rapports spatiaux avec les terrasses quaternaires apportent de nouvelles données permettant des conclusions paléoclimatiques pour cette partie de l'espace carpatique.
Secretagogin is a new neuroendocrine marker in the human prostate
Authors: Adolf Katja , Wagner Ludwig , Bergh Anders , Stattin Pär , Ottosen Peter , Borre Michael , Birkenkamp‐Demtröder Karin , Ørntoft Torben Falck , Tørring Niels 
Published: February 2007

AbstractBackgroundNeuroendocrine (NE) differentiation in prostate cancer (PCa), promoted by NE cell secreted products, appears to be associated with tumor progression, poor prognosis, and hormone‐refractory disease. We recently reported secretagogin, a hexa‐EF‐hand Ca2+ binding protein, as a novel NE marker in carcinoid tumors of the lung and the gastrointestinal tract. The present study analyzes the expression of secretagogin in normal and malign prostate tissue.MethodsWe analyzed immunoreactivity for secretagogin, chromogranin A (CgA), neuron specific enolase (NSE), and synaptophysin (SYN) in consecutive sections from 87 formalin‐fixed paraffin‐embedded (FFPE) benign hyperplastic (n = 10) and prostate adenocarcinoma (n = 77) specimens. The intracellular distribution of secretagogin, CgA, and NSE was examined by confocal fluorescent microscopy, and we characterized secretagogin in eight samples by Western blotting.ResultsSecretagogin is cytoplasmic and nuclear expressed in NE and NE differentiated cells, and to a lesser extent in epithelial cells, in the benign prostate and prostate adenocarcinoma cells. Secretagogin stained 82% (46/56) of benign and 71% (48/68) of prostate adenocarcinomas and co‐localized with the NE markers CgA and NSE. The expression of secretagogin is significantly correlated to CgA (P < 0.001) and NSE (P < 0.048) in prostate adenocarcinoma and to CgA in normal epithelium (P < 0.028).ConclusionsSecretagogin is a novel NE marker in the prostate with more extended immunoreactivity compared to the NE markers CgA, SYN, and NSE. Secretagogin is widely expressed in prostatic adenocarcinoma as opposed to adenocarcinomas in other organs. Prostate 67: 472–484, 2007. © 2007 Wiley‐Liss, Inc.
Understanding the folding and stability of a zinc finger‐based full sequence design protein with replica exchange molecular dynamics simulations
Authors: Li Wenfei , Zhang Jian , Wang Wei 
Published: February 2007

AbstractFull sequence design protein FSD‐1 is a designed protein based on the motif of zinc finger protein. In this work, its folding mechanism and thermal stability are investigated using the replica exchange molecular dynamics model with the water molecules being treated explicitly. The results show that the folding of the FSD‐1 is initiated by the hydrophobic collapse, which is accompanied with the formation of the C‐terminal α‐helix. Then the folding proceeds with the formation of the β‐hairpin and the further package of the hydrophobic core. Compared with the β‐hairpin, the α‐helix has much higher stability. It is also found that the N‐capping motif adopted by the FSD‐1 contributes to the stability of the α‐helix dramatically. The hydrophobic contacts made by the side chain of Tyr3 in the native state are essential for the stabilization of the β‐hairpin. It is also found that the folding of the N‐terminal β‐hairpin and the C‐terminal α‐helix exhibits weak cooperativity, which is consistent with the experimental data. Meanwhile, the folding pathway is compared between the FSD‐1 and the target zinc finger peptide, and the possible role of the zinc ion on the folding pathway of zinc finger is proposed. Proteins 2007. © 2007 Wiley‐Liss, Inc.
The reflection, absorption, and transmission of solar radiation by fog and cloud
Authors: Hewson E. W. 
Published: February 2007

AbstractStarting from Mecke's analysis of the absorption and scattering by water droplets, a system of equations is derived from which may be computed the fractions of the sun and sky radiation incident on a fog or cloud which will be reflected, absorbed and transmitted. These fractions are found to vary with the size of the droplets, the thickness of the fog or cloud, and the density, or amount of liquid water per cubic metre. The zenith distance of the sun also has a slight effect, but this is very small by comparison with the effects of the other variable factors.Drops of radius 2 × 10−3 cm. are taken as typical of fog, and drops of radius 5 × 10−4 as typical of cloud. Table I gives, for fog and cloud, for three values of the density, 0.1 gm./m.3 (diffuse), 1.0 gm./m.3 (moderate) and 5 gm./m.3 (dense), and for thickness of cloud or fog of 20 m., 80 m. and 200 m., and also, for 1,000 m,. and 4,000 m. for cloud, the theoretically computed values of the fractions of incident radiation which are scattered, absorbed and transmitted.A fog is found to reflect less, absorb more, and transmit more, than cloud of the same density and thickness (vertical extent). A diffuse fog of density 0.1 gm/m.3 transmits 98.5 per cent if its thickness is only 20 m., and 86.6 per cent if its thickness is 200 m. In order to reflect 80 per cent of the incident radiation, a cloud of density 1.0 gm./m.3 must have a thickness of at least 150 m., while a cloud of density 5.0 gm./m.3 must have a thickness of at least about 50m.The absorption is greatest in the upper layers of the cloud or fog, and so tends to increase the lapse rte within the liquid bearing layer, but this tendency is masked by the interchange by long‐wave radiation, which cools the upper part of the cloud while warming the lower layers.No observational data are available in a suitable form for comparison with the results displayed in Table I.
Characterization of phenolic compounds in the fruits of Forsythia suspensa by high‐performance liquid chromatography coupled with electrospray ionization tandem mass spectrometry
Authors: Guo Hui , Liu Ai‐Hua , Ye Min , Yang Min , Guo De‐An 
Published: February 2007

AbstractPhenolic compounds are the major bioactive constituents of Forsythia suspensa, an important Chinese herbal medicine used for the treatment of various infectious diseases. Fragmentation behaviors of the phenolic compounds in F. suspensa were investigated by using a high‐performance liquid chromatography/tandem mass spectrometry (HPLC/MSn) method. For common phenylethanoid glycosides, the loss of the caffeoyl moiety was the first fragmentation step, then sequential losses of rhamnose, hexose and water were observed in further fragmentations. If a substituent group presented in the β position, the fragmentation was triggered by initial loss of a substituent group to form structures such as suspensaside A. Then it underwent the common fragmentation pathways as mentioned above, or eliminated characteristic residues of masses 134 or 152 Da, respectively. The latter pathway is reported here for the first time. The fragmentation behaviors of furofuran lignans displayed a typical cleavage of the tetrahydrofuran ring. However, the presence of a hydroxyl group at C‐1 led to the successive loss of 30 Da. Neutral loss of CO2 and benzyl cleavage were characteristic for lignans with a 2,3‐dibenzylbutyrolactone skeleton. A neutral loss of 30 Da was also observed in the fragmentation pattern of flavonols. These fragmentation rules were implemented to analyze phenolic compounds in the fruits of F. suspensa. A total of 51 compounds, including 24 phenylethanoid glycosides, 21 lignans and 6 flavonols, were identified or tentatively characterized based on their retention times, UV spectra and MS fragmentation patterns. Copyright © 2007 John Wiley & Sons, Ltd.
Adduct simplification in the analysis of cyanobacterial toxins by matrix‐assisted laser desorption/ionization mass spectrometry
Authors: Howard Karen L. , Boyer Gregory L. 
Published: February 2007

AbstractA novel method for simplifying adduct patterns to improve the detection and identification of peptide toxins using matrix‐assisted laser desorption/ionization (MALDI) time‐of‐flight (TOF) mass spectrometry is presented. Addition of 200 µM zinc sulfate heptahydrate (ZnSO4 · 7H2O) to samples prior to spotting on the target enhances detection of the protonated molecule while suppressing competing adducts. This produces a highly simplified spectrum with the potential to enhance quantitative analysis, particularly for complex samples. The resulting improvement in total signal strength and reduction in the coefficient of variation (from 31.1% to 5.2% for microcystin‐LR) further enhance the potential for sensitive and accurate quantitation. Other potential additives tested, including 18‐crown‐6 ether, alkali metal salts (lithium chloride, sodium chloride, potassium chloride), and other transition metal salts (silver chloride, silver nitrate, copper(II) nitrate, copper(II) sulfate, zinc acetate), were unable to achieve comparable results. Application of this technique to the analysis of several microcystins, potent peptide hepatotoxins from cyanobacteria, is illustrated. Copyright © 2007 John Wiley & Sons, Ltd.