bluuebunny/crossref_metadata_2025 huggingface dataset:
Electrical stimulation of sacral dermatomes in multiple sclerosis patients with neurogenic detrusor overactivity
Authors: Fjorback M.V. , Van Rey F.S. , Rijkhoff N.J.M. , Nøhr M. , Petersen T. , Heesakkers J.P.
Published: February 2007

Aims

Transcutaneous electrical stimulation of the dorsal penile/clitoral nerve (DPN) has been shown to suppress detrusor contractions in patients with neurogenic detrusor overactivity (NDO). However, the long‐term use of surface electrodes in the genital region may not be well tolerated and may introduce hygienic challenges. The aim of this study was to assess whether electrical stimulation of the sacral dermatomes could suppress detrusor contractions in multiple sclerosis (MS) patients with NDO, hereby providing an alternative to DPN stimulation.

Materials and Methods

A total of 14 MS patients (8 M, 6 F) with low bladder capacity (<300 ml) and a recent urodynamic study showing detrusor overactivity incontinence participated in the study. Three successive slow fill cystometries (16 ml/min) were carried out in each patient. The first filling served as control filling where no stimulation was applied. In the second and third filling electrical stimulation of either the DPN or sacral dermatomes was applied automatically whenever the detrusor pressure exceeded 10 cmH2O.

Results

The control filling showed detrusor overactivity in 12 of the 14 patients. In 10 of the 12 patients one or more detrusor contractions could be suppressed with DPN stimulation. Electrical stimulation of the sacral dermatomes failed to suppress detrusor contractions in all patients.

Conclusions

Although therapeutic effects may be present from stimulation of the sacral dermatomes, we were unable to demonstrate any acute effects during urodynamics. For this reason stimulation of the sacral dermatomes is not an option in a system that relies on the acute suppression of a detrusor contraction. Neurourol. Urodynam. 26:525–530, 2007. © 2007 Wiley‐Liss, Inc.
Changes in T‐type calcium channel and its subtypes in overactive detrusor of the rats with partial bladder outflow obstruction
Authors: Li Longkun , Jiang Chonghe , Hao Ping , Li Weibing , Fan Lixin , Zhou Zhansong , Song Bo
Published: February 2007

Aims

To investigate the activity of the T‐type calcium channel (TCC) and the expression of its subtypes in overactive detrusor (OD) myocytes in rats after partial bladder outflow obstruction (PBOO).

Methods

Thirteen male Wistar rats with OD after PBOO (OD group) and eight sham‐operated rats (control group) were studied. The two groups were compared regarding the expression of TCC subtype genes by reverse transcription‐polymerase chain reaction (RT‐PCR) and the TCC kinetics and cell action potential by whole‐cell patch‐clamp.

Results

The time course and density of the current were significantly higher in the OD cells than those in the control detrusor. Whole‐cell patch‐clamp analysis showed that the activation of TCCs in detrusor myocytes in the OD group was faster than the control group, but inactivation was almost the same in both groups, suggesting a significant enhancement of the Ca2+ “window” current in the OD group. Patch‐clamp recording of action potentials in the OD cells indicated an increase in excitability and a decrease in the repolarization interval. RT‐PCR assay showed an abnormal expression of α1G subtype in the OD cells.

Conclusions

TCCs could be one of the crucial factors for the abnormal excitation in OD cells. The development of OD after PBOO presumably relates to the increase in TCC current in the bladder cells, the enhancement of the Ca2+ “window” current for Ca2+ inflow, the prolongation of the intracellular calcium oscillations, and the acceleration of the cell depolarization. Neurourol. Urodynam. 26:870–878, 2007. © 2007 Wiley‐Liss, Inc.
An adaptive remeshing strategy for flows with moving boundaries and fluid–structure interaction
Authors: Saksono P. H. , Dettmer W. G. , Perić D.
Published: February 2007

The primary objective of this work is to extend the capability of the arbitrary Lagrangian–Eulerian (ALE)‐based strategy for solving fluid–structure interaction problems. This is driven by the fact that the ALE mesh movement techniques will not be able to treat problems in which fluid–structure interface experiences large motion. In addition, for certain problems the need arises to capture accurately flow features, such as a region with high gradients of the solution variables. This can be achieved by incorporating an adaptive remeshing procedure into the solution strategy.

As in our previous works (Comput. Methods Appl. Mech. Eng. 2006; 195:1633–1666; Comput. Methods Appl. Mech. Eng. 2006; 195:5754–5779), here, the fluid flow is governed by the incompressible Navier–Stokes equations and modelled by using stabilized low order velocity–pressure finite elements. The motion of the fluid domain is accounted for by an arbitrary Lagrangian–Eulerian (ALE) strategy. The flexible structure is represented by means of appropriate standard finite element formulations while the motion of the rigid body is described by rigid body dynamics. For temporal discretization of both fluid and solid bodies, the discrete implicit generalized‐α method is employed. The resulting strongly coupled set of non‐linear equations is then solved by means of a novel partitioned solution procedure, which is based on the Newton–Raphson methodology and incorporates full linearization of the overall incremental problem.

Within the adaptive solution strategy, the quality of fluid mesh and the solution quality indicator are evaluated regularly and compared against the appropriate remeshing criteria to decide whether a remeshing step is required. The adaptive remeshing procedure follows closely the standard computational procedure in which the adaptive remeshing process produces a mesh that can capture salient features of the flow field. For the problems under consideration in this work the motion of the fluid boundary very often results in boundaries with very high curvatures and a fluid domain that contain areas with small cross‐sections. To be able to generate meshes that give result with acceptable accuracy these local geometrical features need to be included in determining the element density distribution. The numerical examples demonstrate the robustness and efficiency of the methodology. Copyright © 2007 John Wiley & Sons, Ltd.
First‐trimester ADAM12 and PAPP‐A as markers for intrauterine fetal growth restriction through their roles in the insulin‐like growth factor system
Authors: Cowans Nicholas J. , Spencer Kevin
Published: February 2007

Background

PAPP‐A is a marker used as part of the most effective method of screening for chromosomal anomalies in the first trimester. ADAM12 is a recently discovered pregnancy associated member of the ADAM (a multidomain glycoprotein metalloprotease) family. Recently, ADAM12 has been shown as a potential marker for early screening for chromosomal anomalies. Both PAPP‐A and ADAM12 have been identified as proteases to insulin‐like growth factor binding proteins. In this role, they may have a regulatory function in controlling the amount of free bioactive insulin‐like growth factor (IGF). We therefore wish to examine if the levels of either of these proteases are related to various growth related adverse pregnancy outcomes.

Materials and Methods

PAPP‐A and ADAM12 were measured in a subset of samples collected at 11 to 14 weeks as part of an OSCAR clinic screening for chromosomal anomalies. Follow‐up of pregnancies screened between September 1999 and August 2003 identified 1705 pregnancies with an outcome of intrauterine fetal demise on or after 24 weeks, preterm delivery at 24–34 weeks or 35–36 weeks, very low birthweight (<1.5 kg), low birthweight (<2.5 kg), large birthweight (>4.5 kg), and birth weight below the 3rd or 5th or 10th centile for gestation. A series of 414 normal outcome pregnancies constituted the control group.

Marker levels were adjusted for gestation and maternal weight and the log MoM of the markers were compared using t‐test of unequal variance between the control group and the various adverse outcome groups.

Results

ADAM12 and PAPP‐A concentrations were reduced in low for gestational age birth weights and in all births with weights below 2.5 kg. There was a linear relationship between the severity of the IUGR and the decrease in PAPP‐A and ADAM12. In the larger babies, only ADAM12 was found to be significantly increased in babies above the 90th centile of weight for gestation.

Conclusions

The results of our study are compatible with the proposed role of ADAM12 and PAPP‐A in promoting growth and development by breaking down IGF binding proteins and causing the release of free IGF for uptake into cells to promote growth. In those cases that eventually result in poor fetal growth, levels of PAPP‐A and ADAM12 at 11–14 weeks are significantly lower than normal—in this instance, lowered PAPP‐A and ADAM12 would result in less free IGF being available for cell uptake and growth stimulation. Further studies may elucidate if screening using such modalities can lead to new potential treatments for poorly growing fetuses. Copyright © 2007 John Wiley & Sons, Ltd.
Whole genome amplification from a single cell: a new era for preimplantation genetic diagnosis
Authors: Coskun Serdar , Alsmadi Osama
Published: February 2007

Preimplantation genetic diagnosis (PGD) is a technique used for determining the genetic status of a single cell biopsied from embryos or oocytes. Genetic analysis from a single cell is both rewarding and challenging, especially in PGD. The starting material is very limited and not replaceable, and the diagnosis has to be made in a very short time. Different whole genome amplification (WGA) techniques have been developed to specifically increase the DNA quantities originating from clinical samples with limited DNA contents. In this review, currently available WGA techniques are introduced and, among them, multiple displacement amplification (MDA) is discussed in detail. MDA generates abundant assay‐ready DNA to perform broad panels of genetic assays through its ability to rapidly amplify genomes from single cells. The utilization of MDA for single‐cell molecular analysis is expanding at a high rate, and MDA is expected to soon become an integral part of PGD. Copyright © 2007 John Wiley & Sons, Ltd.
Isolated left‐sided congenital diaphragmatic hernia: cardiac axis and displacement before fetal viability has no role in predicting postnatal outcome
Authors: Kalache Karim D. , Mkhitaryan Monika , Bamberg Christian , Roehr Charles Christoph , Wauer Roland , Mau Harald , Bollmann Rainer
Published: February 2007

Objectives

The purpose of this retrospective study was to determine whether objective assessment of cardiac shifting on two‐dimensional ultrasonography can predict postnatal outcome in fetuses with isolated left‐sided congenital diaphragmatic hernia (CDH).

Materials and Methods

Still images at the level of the four‐chamber view were obtained in 23 fetuses with left‐sided CDH. A group of 12 fetuses (3 non‐survivors and 9 survivors) were examined at two periods, between 20 and 30 weeks and between 31 and 40 weeks. A further 11 fetuses (2 non‐survivors and 9 survivors) were examined between 31 and 40 weeks. Fetal heart axis and position were determined manually and associated with postnatal outcome.

Results

The cardiac axis remained constant in the 9 survivors (15.5 ± 3.2 versus 17.2 ± 3.3, p = 0.71) and 3 non‐survivors (19.0 ± 11.5 versus 18.5 ± 11.8, p = 0.97). There was no statistical difference between the 9 survivors and 3 non‐survivors at the two periods. Cardiac displacement remained constant in the 9 survivors (0.2 ± 0.02 versus 0.2 ± 0.02, p = 0.32) but increased significantly in the 3 non‐survivors (0.2 ± 0.04 versus 0.4 ± 0.02, p = 0.015). The difference between survivors and non‐survivors was statistically significant between the18 survivors and 5 non‐survivors examined between 31 and 40 weeks of gestation (0.2 ± 0.02 versus 0.4 ± 0.02, p = 0.037).

Conclusion

This study does not support the hypothesis that objective assessment of mediastinal shift in fetuses with left‐sided CDH has a role in predicting postnatal outcome before fetal viability, which is when it would be more useful for counseling patients regarding whether to continue with the pregnancy or to opt for termination. Copyright © 2007 John Wiley & Sons, Ltd.
Erratum: Epidemiological assessment of levodopa use in Cuba: 1993–1998
Authors: Lara G. , Cuadrado‐Gamarra J. I. , de Pedro‐Cuesta J. , Esteban E. M. , Giménez‐Roldán S. , Luis‐González S.
Published: February 2007

Epidemiological assessment of levodopa use in Cuba: 1993–1998

G. Lara, J. I. Cuadrado‐Gamarra, J. de Pedro‐Cuesta, E. M. Esteban, S. Giménez‐Roldán, S. Luis‐González

Pharmacoepidemiology and Drug Safety 2006; 15: 521–526

DOI: 10.1002/pds.1150

It has come to the attention of the authors that this published article contained an error.

The above article should have contained the following link to the supplementary material available on the PDS website. This information is as follows:

Supplementary electronic material for this paper is available in Wiley Interscience at http://www.interscience.wiley.com/jpages/10538569/suppmat
The effect of low pressure chemical vapor deposition of silicon nitride on the electronic interface properties of oxidized silicon wafers
Authors: Jin Hao , Weber K. J.
Published: February 2007

The effect of LPCVD Si3N4 film deposition on oxidized Si wafers, to form Si3N4/SiO2/Si stacks, is studied using capacitance–voltage and carrier lifetime measurements. The deposition of a nitride film leads to an increase in the density of defects at the Si–SiO2 interface, with the increase being greater the thinner the oxide. However, even the presence of a very thin intermediate oxide results in a dramatic improvement in interface properties compared to the direct deposition of the Si3N4 film on Si. The interface degradation occurs in the initial stages of nitride film deposition and appears to be largely the result of increased interfacial stress. Subsequent thermal treatments do not result in significant further degradation of the Si–SiO2 interface (except for a loss of hydrogen), again in contrast to the case where the nitride films is deposited onto Si. Copyright © 2007 John Wiley & Sons, Ltd.
Isosteres of peptides: boron analogs as dipolar forms of α‐amino acids – a theoretical study
Authors: Malde Alpeshkumar K. , Khedkar Santosh A. , Coutinho Evans C.
Published: February 2007

Modification of peptides to produce peptidomimetics is of great interest, with the aim of designing potent, selective, and metabolically stable analogs having certain conformational properties. Organoboranes have been reported in the literature with a wide range of therapeutic applications. One of the therapeutically important class of molecules is amine‐carboxyboranes derived from amino acids by replacement of the Cα atom of an amino acid/peptide by boron. The conformational preferences of these peptides, with respect to backbone ω, ϕ, and ψ torsion angles, have been investigated by theoretical calculations. The amide bond in these molecules has the same geometry in the ground and transition states as the natural peptides. However, the boron isosteres of glycine and alanine peptides are less structured than their natural derivatives, but are distinguished by structures with a positive value for the ϕ angle, which is normally disfavored for natural peptides. This property could be used to build peptides with a geometry not usually seen in natural peptides. Copyright © 2007 John Wiley & Sons, Ltd.
Polyester nanoparticles by non‐aqueous emulsion polycondensation
Authors: Müller Kevin , Klapper Markus , Müllen Klaus
Published: February 2007

A versatile non‐aqueous emulsion polycondensation process for the mild fabrication of polyester nanoparticles is presented. Spherical nanoparticles with diameters smaller than 60 nm are prepared in non‐aqueous emulsion systems. These emulsions consisted in one case of DMF dispersed in n‐hexane and in a second with acetonitrile dispersed in a continuous cyclohexane phase. Stabilization of these systems was achieved by using a polyisoprene‐polymethylmethacrylate block copolymer. The suitability of these aprotic emulsions for synthesizing polyester nanoparticles by emulsion polycondensation having molecular weights up to 22,000 g/mol is demonstrated. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 1101–1108, 2007
Quality of life of patients with gastric cancer in Taiwan: validation and clinical application of the Taiwan Chinese version of the EORTC QLQ‐C30 and EORTC QLQ‐STO22
Authors: Huang Chi‐Cheng , Lien Heng‐Hui , Sung Yung‐Chuan , Liu Han‐Ting , Chie Wei‐Chu
Published: February 2007

The relatively high incidence of gastric cancer in Taiwan warranted the need of a disease‐specific quality of life (QOL) instrument. We translated the EORTC QLQ‐C30 and QLQ‐STO22 according to the guidelines from the EORTC. A total of 100 patients were interviewed. Convergent and discriminant validity, Cronbach's alpha coefficient and known‐groups comparisons were used to examine the reliability and validity. We found good reliability for multi‐item subscales of the QLQ‐C30 and QLQ‐STO22 (Cronbach's alpha coefficient: 0.70–0.94) except cognitive functioning of the QLQ‐C30 and eating restriction of the QLQ‐STO22. Patients in the active treatment group experienced compromised functional status and worse treatment‐associated symptoms than those in the follow‐up group. Similar results were found in comparisons based on Eastern Cooperative Oncology Group (ECOG) Performance Status and dysphagia grades. The study has ascertained the cross‐cultural validity, reliability and clinical applicability of the Taiwan Chinese version of the EORTC QLQ‐C30 and QLQ‐STO22. Copyright © 2007 John Wiley & Sons, Ltd.
Analysis of the segmentation in the profile of alpine talus slopes
Authors: Francou Bernard , Manté Claude
Published: February 2007

A method for analysing the segmentation in the profile of talus slopes is used in an Alpine periglacial environment. Two populations of talus slope profiles are examined according to the development of their headwalls. Beneath massive rockwalls the profile appears bi‐segmented: a break point situated at a constant angle (33–34 degrees) divides an extensive proximal segment with a shallow curvature from a shorter and more concave distal segment. When the headwall disappears, the segmentation is modified and a concavity extends throughout the profile. A new model for talus slope formation is proposed in which the rockfall mechanism and the removal processes are combined.
Niveo‐aeolian sedimentation and resulting sedimentary structures; søndre strømfjord area, Western Greenland
Authors: Dijkmans J. W. A.
Published: February 2007

Winter observations were carried out on aeolian sand sheets in Western Greenland, in order to obtain insight into the occurrence and influence of niveo‐aeolian sedimentation in modern cold‐climate sand‐sheet environments. The alternating or simultaneous aeolian transportation of snow and sand appears to form an important factor in the sedimentation. Niveo‐aeolian beds develop annually and are deposited during a period when the snow cover is thin. They are covered by clean snow when sand transport is impeded by ample snow or insufficient wind velocity.

The nature and significance of denivation features in the sedimentological record are equally poorly understood. In order to study these snow‐related structures, the winter observations are compared with sections trenched in summer when no snow was left. After desiccation of the surface in summer, the sediments deriving from the niveo‐aeolian beds on planar and low‐angle inclined surfaces are likely to be redistributed by wind action. However, on slip faces denivation structures are frequently preserved as deformation of cross‐strata and a model of their association is presented. Most of these structures resemble deformation structures previously described in wetted sand, but their association, indicating (1) collapse due to volume reduction and (2) the alternation of deformed and undeformed sedimentary units, form diagnostic indicators of cold‐climate aeolian deposits.
Observations of winter aeolian transport and niveo‐aeolian deposition at crater lake, pangnirtung pass, N.W.T., Canada
Authors: Neuman Cheryl Mckenna
Published: February 2007

Annual observations of aeolian transport in an arctic proglacial setting indicate that summer transport is minimal when frequent precipitation occurs and water levels are high, but that autumn and winter transport is much more significant than is usually assumed. Strong katabatic winds and low snowfall are typical of the winter season, so that bare frozen surfaces contribute grains to the transport load through sublimation and abrasion. During violent winter sandstorms, coarse granules are suspended up to 4 m above the surface and conventional instrumentation grossly underestimates the transport load. Most of the depositional record of this transport is erased during flooding of the sandur in the following season. Relatively light summer winds winnow out the fine fraction of the coarse, poorly to moderately sorted winter aeolian deposits, so that a lag develops on the surface of thin aeolian sand sheets lining the sandur.
Stratification mechanisms in slope deposits in high subequatorial mountains
Authors: Francou Bernard
Published: February 2007

An analysis of the processes active in the frost environment of high subequatorial mountains makes it possible to propose a model for the stratification of slope deposits. Bedding is generated by solifluction sheets which move at the speed of a few cm y−1. Solifluction involves needle ice, frost creep and gelifluction, and the ground thickness concerned is less than 20 cm. Sorting takes place by frost heaving. Coarse particles are concentrated at the front of the sheets, where matrix materials tend to be washed away, and are then buried by the advancing fine layer. Sedimentary characteristics allow recognition of several diagnostic features which can be used to indicate the origin of bedding in relic slope deposits situated in mid‐latitudes. This model offers an alternative to earlier concepts of the stratification of slope deposits, but further studies are required, since other processes may also generate similar bedding features.
Un pingo en système fermé dans des dolomies paléozoïques de l'arctique canadien
Authors: St‐Onge Denis A. , Pissart Albert
Published: February 2007

Si quelques pingos en système ouvert ont été observés dans des formations de roches dures de régions à pergélisol continu, un seul pingo en système fermé soulevant des roches consolidées paléozoïques a été, à notre connaissance, mentionné dans les éerits scientifiques. Toutefois, à ce jour, très peu de renseignements ont été fournis concernant ce pingo particulier.

A la suite d'une étude régionale précisant comment s'est effectué le retrait glaciaire dans la région septentrionale du District de Mackenzie où ce pingo a été observé, des précisions peuvent ětre apportées sur les caractéristiques et la genèse probable de ce pingo.

L'édification de cette forme est, croit‐on, liée à la perméabilité exceptionnelle des dolomies fortement fissurées au sein desquelles a dǔ exister une nappe aquifère. Celle‐ci aurait été mise sous pression par le gel à la suite de la vidange d'un lac proglaciaire, selon le schéma maintenant classique expliquant l'apparition des pingos du delta du fleuve Mackenzie.
Periglacial evidence from the western Cape Mountains, South Africa: A progress report
Authors: Boelhouwers J.
Published: February 2007

Extensive Pleistocene debris deposits occur in the Western Cape Mountains, South Africa. Although a cryogenic origin for the clasts is generally accepted, there is still discussion about the conditions under which debris transport and deposition took place. In the Waaihoek Mountains solifluction features occur at 1800m a.s.l. Present‐day periglacial activity results from surficial soil frost action and snowfalls in the cold season. To assess the significance of freeze‐thaw action on soil movement rates, continuous and periodic measurements are being made of climatic parameters and soil movement at several experimental sites, including a snowpatch site, at 1850m a.s.l. in the Waaihoek Mountains.
Cryoplanation surfaces in the central andes at latitude 35º S
Authors: Grosso Santiago A. , Corte Arturo E.
Published: February 2007

A survey of cryoplanation surfaces in the Andean mountain range near latitude 35º south, and longitude 70º west shows cryoplanation surfaces are present on plutonic, volcanic, sedimentary and metamorphic rocks. Gypsum mountains above the lower limit of permafrost do not show cryoplanation. Most cryoplanation terraces are in areas with mean annual air temperature below −1ºC, (i.e. above the lowest limit of sporadic permafrost at 2800 m). The largest cryoplanation surfaces are observed on sedimentary rocks and located in areas where mean annual air temperatures are near 0ºC. Possibly, these surfaces are inactive under the present climate and were formed in a colder, past cryogenic episode.

The largest cryoplanation surfaces are formed in sedimentary rocks, followed by volcanic, metamorphic and intrusive rocks. Gypsum rocks of low frost susceptibility (non‐porous) do not produce cryoplanation terraces. Cryoplanation is thought to be the result of frost shattering, frost heave and gelifluction of frost‐susceptible (porous) rocks in a climate with numerous freeze‐thaw cycles.
Caractérisation du Pergélisol de Buttes Cryogènes à l'Aide de Diagraphies Électriques au Nunavik, Québec
Authors: Fortier R. , LéVesque R. , Seguin M. K.
Published: February 2007

Electrical loggings for permafrost characterization in cryogenic mounds in Nunavik, Québec. Geophysical methods are useful tools to improve the understanding of physical phenomena related to permafrost. Induced polarization logging has not been commonly used yet for permafrost studies. In this study, electrical contact is insured through regularly spaced metallic electrodes vertically inserted in the ground along a multiconductor cable. Thermistors located at the same depths yield a temperature profile in the soil. Both apparent electrical resistivities and apparent electrical chargeabilities are logged. A dipole‐dipole configuration is used. The spacings between the electrodes of a dipole vary from 0.1 to 1 m. Two study areas (Kangiqsualujjuaq in Ungava Bay and Umiujaq in Hudson Bay) in northern Quebec are investigated; they are both located at the tree line and have a mean annual air temperature of about −5.6ºC. The base of permafrost is easily detected through the high contrasts in apparent electrical resistivity and apparent chargeability between frozen and unfrozen soils. Ice‐rich permafrost is characterized by high resistivity values and close to zero chargeability values, while ice‐poor permafrost is characterized by intermediate resistivity and low chargeability values. In unfrozen zones, low apparent resistivity and high apparent chargeability (positive or negative) values are encountered. These guidelines for the interpretation of the logs allow a categorization of different subhorizontal zones in permafrost. Ice‐rich zones do occur near the surface and at the base of permafrost. A low ice content zone is usually sandwiched between these two zones. In this central zone, the growth of ice lenses is limited due to the small intake of water which is damned by the icy zones above and below.
Solifluction and the Role of Permafrost Creep, Eastern Melville Island, N.W.T., Canada
Authors: Bennett L. P. , French H. M.
Published: February 2007

In situ measurements of solifluction and permafrost creep on several low‐angled slopes near Rea Point, Melville Island, emphasize that there is no clear relationship between the two processes. Solifluction and permafrost creep are essentially independent in time (e.g. early summer versus late summer dominance) and mechanics (e.g. the flow of saturated sediments versus the plastic flow of ice‐rich sediments). Such differences are also likely to alter the relative importance of each of these mass‐wasting processes on a slope.
Differential frost heave, load casting and convection: Converging mechanisms; a discussion of the origin of cryoturbations
Authors: Van Vliet‐Lanoë Brigitte
Published: February 2007

This paper reviews and discusses the main mechanisms involved in cryoturbation processes and patterned ground. The arguments are based upon field, thermal, moisture and micromorphological data in relation to cryogenic fabric stability and local hydraulic conditions. Differential frost heaving appears to be the main mechanism of cryoturbation, but its action can be helped by cryostatic pressures, by differential swelling and probably also by load casting in poorly drained sites. Differential frost heaving can be emphasized if organics are present. Frost‐susceptibility gradients provide an understanding of the geometry of deformations.
A periglacial stratified slope deposit in the valley and ridge province of central Pennsylvania, USA: Sedimentology, stratigraphy, and geomorphic evolution
Authors: Gardner Thomas W. , Ritter John B. , Shuman Christopher A. , Bell James C. , Sasowsky Kathryn C. , Pinter Nicholas
Published: February 2007

The sedimentology and stratigraphy of a stratified slope deposit in central Pennsylvania together with existing pollen data and global climate simulations are used to develop a model for stratified slope deposition within the context of a waxing and waning Late Wisconsinan periglacial climate. The deposit consists of well‐stratified beds of platy, subangular shale chips ranging in size from very fine to very coarse gravel and is characterized by two facies: a matrix‐supported facies and a clast‐supported facies. Mechanical breakdown of bare, highly fractured shale bedrock by frost shattering and freeze‐thaw activity in a periglacial environment in front of the Late Wisconsinan glacial boundary provided an abundant and continuous sediment supply. Gelifracts were transported from bedrock source areas to depositional sites along valley side‐slopes by sheetwash and debris flow processes, creating an inclined (10º), aggradational surface of low relief. Surface runoff was derived from snow melt and rainfall onto impermeable frozen ground and bedrock surfaces. The cyclic nature and timing of deposition indicate that sediment was produced and transported immediately prior to and after the Late Wisconsinan glacial maximum. The Late Wisconsinan glacial maximum was characterized by permafrost conditions with reduced sediment supply and erosional truncation of the stratified slope deposit. Frost cracks, ice wedges and soil wedges developed on an unconformity within the deposit during the glacial maximum.
Observations of aeolian transport and niveo‐aeolian deposition at three lowland sites, Canadian arctic archipelago
Authors: Lewkowicz Antoni G. , Young Kathy L.
Published: February 2007

Observations of wind action were made in the late winter, spring and summer at three lowland sites located on Banks Island (1977‐79), Melville Island (1986‐87) and Ellesmere Island (1989‐90). Erosion pin measurements in north‐central Banks Island showed minimal activity on interfluves and the highest rates at a blowout site in an unvegetated sand plain. The timing of aeolian activity during the year depended on the site characteristics. Where the snow cover was incomplete in winter, either because a rugged microtopography resulted in terrain elements protruding above the surface of the snow or because sublimation of snow exposed the ground surface, aeolian transport could occur year‐round. In areas with a flatter microtopography, summer transport took place but deflation was negligible over the winter and niveo‐aeolian deposition was confined to the autumn and spring when the snow cover was patchy. Windblown sediment became spatially concentrated by denivation at some sites and was deposited on slopes as fans or layers up to 8 cm thick. In the years this occurred, the rate of deposition was greater than sediment removal by wash or other processes and, at least in the short term, the form of the slope was changed.
Ice‐wedge casts of Wisconsinan age in Eastern Nebraska
Authors: Wayne William J.
Published: February 2007

Sand‐filled, wedge‐shaped structures beneath a thin layer of aeolian sand penetrate a pre‐Illinoian till and gravel in northeastern Nebraska. Interpreted to be relic thermal contraction crack wedges, they provide the first definite evidence in this State of the former presence of permafrost. The wedges are 5‐7 m apart, 1.8‐2.8 m deep and 0.6‐0.9 m across at the top, taper downward to a crack and intersect to form polygons. They are filled with medium sand that contains mostly rounded and frosted grains. Vertical fabric is present in each wedge. Ventifacts lie along the top of the till, which is covered by 0.3‐0.4 m of interlaminated medium and fine sand that grades upward into 1.0 m of Peoria Loess.

These sand wedges formed in thermal contraction cracks, in dry, windswept areas 25‐50 km south of the Late Wisconsinan ice margin, where snow cover was minimal, so that blown sand fell into the open cracks. They probably required mean annual temperatures of —6 °C to —8 °C or lower, along with strong winds and rapid drops in temperature. Yardang‐like topography, beyond the limit of Wisconsinan till across central South Dakota and northeastern Nebraska, is further evidence of exceptionally strong winds parallel to the ice margin during the Late Wisconsinan glacial maximum, between 22 and 18 ka.
Ploughing blocks of the Tien Shan
Authors: Gorbunov A. P.
Published: February 2007

Ploughing blocks (boulders) consist of three elements, namely, a rock fragment, a mound and an elongate depression. The movement of a block downslope leads to the formation of a pressure mound ahead of the block, while in its rear there is a furrow. In the Tien Shan mountains the size of the largest ploughing block is ≈11 m3, the height of the largest mound is about 1.0 m and the most elongated furrow is ≈37 m long.

Seasonally frozen ground below the blocks or in their immediate vicinity gives rise to their movement. Seasonal freezing is the key factor that dictates a high ice content and ground moisture beneath the block which causes the gliding downslope. The block movement velocity is not regular and reaches its maximum in the second half of spring. Velocity varies also from year to year: in certain years it is nil and sometimes it is high as 7‐10 cm a year.
Age of growth of two pingos, Sarqaq Dalen, West Central Greenland
Authors: Yoshikawa Kenji
Published: February 2007

The aim of this note is to identify the beginnings of growth of two pingos located in Sarqaq Dalen, west‐central Greenland. One is located at the toe of an alluvial fan, and seems to be active; the other is on a river bed, and already collapsed. Marine sand covers the pingos and indicates that the Holocene transgression predates their growth. The pingos are located approximately 2 km from the present coastline. Pollen analysis of the overlying sediments of the two pingos leads to the following conclusions: (1) although the study area had already emerged from the sea at Post Fjord stage (7800 years BP), it was submerged again sometime between 7000‐5000 years BP; (2) one pingo started its growth approximately 4500 years BP; (3) the other pingo started its growth approximately 6000‐5500 years BP.
Changes to the permafrost environment after forest fire, Da Xi'an Ridge, Gu Lian Mining Area, China
Authors: Lin‐Heng Liang , You‐Wu Zhou , Jia‐Cheng Wang
Published: February 2007

Permafrost field investigations in the Gu Lian Mining area of Great Xi'an Ridge (in Chinese: DA HINGAN LING) was undertaken in the second year following a forest fire. It was found that after the fire air temperature, ground temperature, evaporation (measured by pan) and wind velocity increased but humidity, ground ice and water content decreased. These changes led to an increase in seasonal thaw depths. These results illustrate that the permafrost environment is changed greatly by forest fire.
Permafrost and ground ice conditions reported during recent geotechnical investigations in the Mayo district, Yukon territory
Authors: Burn C. R.
Published: February 2007

The Mayo District, Yukon Territory, lies in the widespread discontinuous permafrost zone. Permafrost thicknesses of up to 40 m have been measured in valleys, and of 135 m at higher elevations. Many observations of ground ice have been made by placer miners, but generally these are unrecorded. Recently, over 200 shallow geotechnical boreholes have been drilled in the area in association with municipal or highway construction. Ground ice is usually encountered at undisturbed sites within 4 m of the surface. In the main valleys at elevations below 1100 m a.s.l. coarse, clastic, outwash materials, sand dunes and slopes with southerly aspect are usually frost‐free. Stripping of vegetation for construction or placer mining leads to permafrost degradation, but permafrost can re‐establish as vegetation regenerates. Ground temperatures at Mayo and Keno Hill indicate a geothermal flux of over 0.1 W/m2.
A model of the rate of frost shattering: Application to field data from Japan, Svalbard and Antarctica
Authors: Matsuoka Norikazu
Published: February 2007

An empirical model of the rate of bedrock frost shattering (Matsuoka, 1990b) was applied to field data obtained from four different environments: Japanese lowland and alpine regions, Svalbard and Antarctica. The model indicates that the annual frost shattering rate is a function of freeze‐thaw frequency per year, degree of saturation and bedrock tensile strength. Field measurements of these parameters were carried out for 1‐6 years on rockwalls in the four study areas. Despite the differences in thermal and moisture conditions, the model agreed fairly well with the field data, with the exception of those from Antarctica and part of Svalbard, where moisture is insufficient for frost shattering. The model predicts the weathering rates of bedrock situated in environments where frost shattering prevails.

Un modèle empirique de la vitesse de désagrégation par le gel (Matsuoka, 1990b) a été appliqué aux données de terrain obtenues dans 4 environnements différents, à savoir: les basses terres et les régions alpines du Japon, Svalbard et l'Antarctique. Le modèle indique que la vitesse annuelle de désagrégation est fonction de la fréquence annuelle des cycles gel/dégel, du degré de saturation des roches et de la limite élastique à la traction. Des mesures de ces paramètres ont été réalisées pendant des durées variant de 1 à 6 ans sur des faces rocheuses dans les 4 régions étudiées. Bien que des différences existent dans les conditions thermiques et les conditions d'humidité, le modèle cadre bien avec les données de terrain, sauf dans l'Antarctique et une partie de Svalbard où l'humidité est insuffisante pour provoquer la désagrégation par le gel. Le modèle prédit les vitesses de gélivation du bedrock dans des enrionnements où la désagrégation par le gel est prépondérante.
Frost heave mechanism in welded tuff
Authors: Akagawa Satoshi , Fukuda Masami
Published: February 2007

Segregation freezing, one of the heave mechanisms in freezing soils, is shown to be responsible for the breakdown of freezing welded tuff. Frost heave tests of welded tuff have proved that segregation freezing occurs in rock by revealing ice lens growth, pore water flow and the existence of hydraulic gradient driving water to the freezing front.

The physical characteristics of the tuff, such as pore microstructure, mineral composition, unfrozen water conditions, permeability, and so forth, are similar to those of frost‐susceptible soils.

An empirical equation, derived from the tuffs water retention curve and unfrozen water content measurements with pulsed NMR, relates the segregation freezing temperature and frost heave pressure. This equation is discussed in the context of the governing thermodynamics. We suggest that the segregation freezing concept is generally applicable to common rocks.

La formation de glace de ségrégation, processus bien connu dans le gel des sols est responsable de la fracturation par le gel des tuffs cimentés à chaud. La formation de la glace de ségrégation est démontrée par la croissance de lentilles de glace, l'écoulement de l'eau des pores et l'existence d'un gradient hydraulique amenant l'eau au front de gel.
Rock Properties as Controls on Free‐face Debris Fall Activity
Authors: Douglas George R. , Whalley W. Brian , McGreevy James P.
Published: February 2007

A free face composed of basalt flows showed, over a 72 week observation period, considerable variation in yield (kg or m3) of fallen material. Yield peaks in spring and autumn were recorded but small contributions were made from all flows throughout the year. The incidence of frost action cannot account for all of the yield peaks. An explanation of free‐face weathering can best be given by taking the microcrack crack system into account in relation to some simple rock properties. Although there are several factors involved, microcrack density and coefficient of loosening are useful indicators of flow behaviour. An explanation of rock removal which takes material properties into account as well as environmental or climatic conditions is to be preferred and can be applied as a general model for all climates.
Evidence for enhanced mechanical weathering associated with seasonally late‐lying and perennial snow patches, Jotunheimen, Norway
Authors: Berrisford Mark S.
Published: February 2007

At two snow patch sites in Jotunheimen, Norway, direct evidence of surface fracturing and splitting of boulders was collected to quantify spatial variations in the amounts of mechanical weathering associated with snow patches. Transects between external control and internal sites display a 3‐5‐fold increase in the percentage of clasts affected by mechanically induced fracture processes. Up to 50% of clasts within the internal areas of the snow patches exhibit either surface flaking or more severe fracturing; this contrasts with up to 15% of clasts exhibiting evidence of mechanical weathering at the snow patch peripheries. The results indicate that the snow patches significantly enhance mechanical weathering processes and that maximum mechanical weathering is associated with the average annual retreat position of the snow margin.
Hydrogen and oxygen isotopes and the origin of the ice in peat plateaus
Authors: Harris Stuart A. , Schmidt Irena H. , Krouse H. Roy
Published: February 2007

δ18O and δD values (% SMOW) were measured on 159 samples from the active layer and permafrost on peat plateaus and from the adjacent fen at sites about 50 km north of Tuchitua along the Robert Campbell Highway in southeastern Yukon Territory. The regression lines for the samples from the active layer and the permafrost were very similar, which suggests that they both contained mainly water from meteoric sources. The water samples from the fen produced results which gave a noticeably different regression line, so that it appears that the icy core of the peat plateaus is the result of downward penetration of precipitation into permafrost rather than freezing water migrating from the surrounding fen. These relationships appear to be constant throughout the study area, and there is no evidence of the ice being from an earlier, colder period. The precipitation in this area of the Yukon Territory shows a δD versus δ18O behaviour somewhat like that reported for Whitehorse in the literature.
La gélivation des parois rocheuses dans une glacière du jura neuchǎtelois
Authors: Pancza André
Published: February 2007

L'enregistrement de la température et les mesures de l'humidité de la roche dans la glacière de Monlési ont révélé les conditions microclimatiques très particulières dans lesquelles s'effectue la gélivation de cette cavité souterraine. La très grande efficacité du gel est en apparente contradiction avec les quelques cycles de gels‐dégels annuels enregistrés. Cette intense gélivation des parois et du plafond de la glacière s'explique par le fait, que le gel agit dans une roche imbibée, voire saturée d'eau.

Vu la rareté des glacières, leur impact sur l'évolution morphologique jurassienne est insignifinate. Cependant, au cours du Quaternaire, au début et à la fin des époques glaciaires, il n'est pas exclu que la plupart des cavités karstiques di Jura aient abrité une lentille de glcae. Si l'intensité de la gélivation fur celle que nous constatons aujourd'hui, ces dépressions karstiques s'avèrent ětre des formes mixtes, dues à la dissolution mais aussi à la gélivation.
Holocene periglacial processes and environmental changes in Daqingshan mountains, inner Mongolia, China
Authors: Zhijiu Cut , Changqing Song
Published: February 2007

Periglacial phenomena and palaeobotany evidence of environmental changes are present in the Daqingshan area, northern China. This arid‐semiarid area is sensitive to climatic change. There were four climatic periods during the Holocene. During the Hypsithermal, the annual mean temperature was 1–2 °C higher than today. On the other hand, the annual mean temperature was 2.0–2.5 °C lower during recent glaciation and about 7 °C lower at the end of the Late Pleistocene. The fluctuation of vertical vegetation belts was about 200–600 m during the Holocene.

Des phénomènes périglaciaires et des observations paléobotaniques démontrent l'existence de changements de l'environnement dans la région de Daqingshan, au nord de la Chine. Cette région aride ou semi‐aride est très sensible aux changements climatiques. Quatre périodes climatiques ont été reconnues pendant l'Holocène. Pendant l'Hypsithermal, la température moyenne annuelle était 1 á 2 °C plus élevée qu'aujourd'hui. D'autre part, la température moyenne annuelle était 2,0 a 2,5 °C plus basse pendant la glaciation récente et environ 7 °C plus élevée à la fin du Pléistocène. Les modifications des limites verticales de la végétation pendant l'Holocène ont été comprises approximativement entre 200 et 600 m.
Vertical movements of boulders in a subnival boulder pavement at 2800 m a.s.l. in the Alps (France)
Authors: Pissart A. , Francou B.
Published: February 2007

Vertical movements of boulders within a subnival boulder pavement were measured at 2800 m a.s.l. in the Alps over a period of 10 years. It was demonstrated that some boulders are undergoing sinking and others upheaving. The upheaving occurs in autumn during ground freezing, while the sinking of boulders probably occurs in springtime when the ground temperature is below 0 °C under the snow patch.
Recent microweathering phenomena in southern and central Sweden
Authors: Swantesson Jan O. H.
Published: February 2007

More than 200 weathering sites, in southern and central Sweden, representing different rock types and environments have been investigated. Field studies were complemented by thin‐section examination and laboratory simulation experiments. Research results in a classification of weathering forms in crystalline rocks in cool temperate climates. Special attention is paid to Holocene microweathering, facilitated because glaciation removed most old weathered material. Only minor forms, including surface colorations, mineral weathering, pitting and flaking, have been produced entirely during the Holocene. Where recent breakdown is observed, the primary reason must be sought in the geological history of rock. Holocene microweathering a few cm in depth is caused by a complex interaction between different weathering processes. Salt crystallization, however, seems important in areas that have experienced seashore conditions. Often the forms produced are as much the result of rock properties as of actual weathering processes.
Periglacial phenomena and pleistocene environmental conditions in the Netherlands—An overview
Authors: Vandenberghe J.
Published: February 2007

During the IGU/IPA Symposium entitled ‘Periglacial Environments in relation to Climate’ (3–6 May 1991) prominent aspects of modern periglacial research in the Netherlands were presented in a field excursion. This paper highlights the Dutch Pleistocene periglacial environments within the framework of palaeoclimatology, sedimentology and geomorphology.