bluuebunny/crossref_metadata_2025 huggingface dataset:
Mass Balance Studies on the Hintereisferner, Ötztal Alps, 1952–1961
Authors: Hoinkes H. , Rudolph R.
Published: September 2017

Investigations of the mass balance of the Hintereisferner are dealt with for the period 1952–61. Ablation of ice was measured with stakes, ten of which per square kilometre were considered as a sufficient number. The area of ice ablation terminates in the “zero-line of ice ablation”. The net accumulation was studied in pits, and by mapping of enduring accumulation patterns. In order to avoid errors it is proposed that the term “firn line” be replaced by the term “old snow line”. This would more clearly emphasize that only the net accumulation of old snow from the current budget year is a gain of mass for the glacier. The term “firn”, in accordance: with Flint’s [1957] definition should be used only for snow more than one year old. Between the old snow line and the zero-line of ice ablation in some years an appreciable firn ablation takes place. The mass balance reveals a large variation between +0 77×106m.3 of water in the most favourable budget year 1954–55, and −9.83×106m.3 of water in the most unfavourable budget year 1957–58. The average annual mass balance was −3.60×106m3 of water, with an estimated maximum possible error of about ±0.54×106m3 of water.
Zonation in the Accumulation Area of the Glaciers of Axel Heiberg Island, N.W.T., Canada
Authors: Müller Fritz
Published: September 2017

Mass budget studies on the glaciers of Axel Heiberg Island, Canadian Arctic Archipelago, during the summers of 1959–61, resulted in recognition of five distinct zones in the accumulation area. The 1961 data from these zones of the main glacier investigated are presented. The implication is made that the long-term changes in size, elevation and net accumulation of these zones can be utilized as climatic indicators.
Variability of Lake Ice Growth and Quality in the Schefferville Region, Central Labrador—Ungava
Authors: Andrews J. T.
Published: September 2017

An examination of rates of ice growth, actual ice thickness and the quality of the lake ice profile on Knob Lake, central Labrador—Ungava, showed that all these factors were extremely variable. Three sites were established on Knob Lake from 1957 to 1961, and a similar sequence of sites was established on a neighbouring lake, Maryjo Lake, from 1959 to 1961. Significant variations occurred within a single lake body from site to site, though it was noted that certain patterns of ice growth and quality did occur throughout most years and could be directly related to patterns of snow accumulation on the lake. Variations from lake to lake were found to be least at the centre lake sites, probably because snow cover was always least at these sites and would not affect heat loss so greatly as at the marginal sites. It is suggested that the majority of empirical formulae proposed for lake ice growth are unrealistic for short-term forecasting of ice thickness and growth, and even long-term forecasting, using accumulated degree-days of frost, only gives average values. The only answer is repeated samplings on any lake, until such time that sufficient data are gathered for a full statistical approach based on probability analysis.
Gravity Measurements on the Athabaska Glacier, Alberta, Canada
Authors: Kanasewich E. R.
Published: September 2017

The thickness of the Athabaska Glacier has been obtained along eight transverse profiles by an investigation of gravity anomalies. Three-dimensional computations with a low-speed digital computer were made in this study to acquire more precise results than previously obtained. The thickness of the glacier varies front 326 m. on a line below the lower ice fall to 49 m. near the terminus. The accuracy of the results is discussed and compared with independent data from bore holes and a seismic program. The cross-section of the glacier valley was found to approximate a parabola on several lines. From a knowledge of the thickness. shape and surface slope of the glacier, the average shear stress exerted by the bed on the ice was found to be 1.0 bar.
Some Crystal Growth Features of Sea Ice
Authors: Bennington Kenneth O.
Published: September 2017

Laboratory studies of the supercooling and freezing of baths of sea-water are described and compared with features of natural sea ice. By using dyes the convection cells in the sea-water test baths could be studied. and the growth of crystals relative to this cell structure could be observed. Brine expelled by the separation of ice from the system commonly followed the pre-existing convection channels. Sections of sea ice are interpreted in the light of these observations, and sea ice is shown to inherit drainage channels and banding features from the characteristics of the parent liquid system.
Results of Measurements in the 309 Meter Bore Hole at Byrd Station, Antarctica
Authors: Gow Anthony J.
Published: September 2017

Temperature, inclination, and closure have been measured in a 309 m. deep drill hole at Byrd Station, Antarctica. The results of five series of measurements taken yearly since February 1958 show that temperatures below 70 m. have remained constant since December 1958, that the closure rate has accelerated, and that the hole has undergone negligible inclination from the vertical. Anomalous temperatures in the upper levels of the drill hole are attributed to the steel casing that was permanently emplaced to a depth of 36 m. during drilling in 1957–58. A positive temperature gradient was observed in the casing, but negative gradients exist below the casing and a constant gradient profile is developed below 170 m. Both ice motion and climatic changes at Byrd Station are thought to have contributed to the formation of the observed negative temperature gradients. Insignificant bending of the drill hole would imply negligible differential motion in the upper 300 m. of the 2,400 m. thick ice sheet at Byrd Station. The rate of hole closure has accelerated throughout the 4 yr. period of observations, except at the bottom of the drill hole, where the most recent measurements (February 1962) show that some constraint is now developing. Deformation rates throughout the drill hole are not proportional to some constant power of the stress; instead the value of the power has been found to increase with both increasing stress and time of application of stress. This behavior is attributed to some process of continuous deformational recrystallization of ice in the walls of the drill hole. A recoring of the deformed drill hole to investigate such effects is advocated.
Arctic Sea Ice of Various Ages: II. Elastic Properties
Authors: Pounder E. R. , Langleben M. P.
Published: September 2017

Young’s modulus E and Poisson’s ratio σ0 were calculated for biennial and polar ice from measurements of the P-wave velocity in small samples and from a study of the resonant frequencies of the saure samples. P- and S-wave velocities in the biennial ice cover were also found by a seismic method. The small-scale tests showed no significant differences between the two types of ice tested. Young’s modulus averaged 3.6 per cent lower than the comparable figure for annual sea ice. The seismic method gave values of E and σ0 about 20 per cent lower than the small-scale tests.
Rate of Growth or Shrinkage of Nonequilibrium Ice Sheets
Authors: Weertman J.
Published: September 2017

An analysis is made of the time required to build up an ice-age ice sheet and of the time required to destroy such an ice sheet. The calculations are based on the approximation that the theory of perfect plasticity is valid. It is concluded that the time required to build up an ice-age ice sheet is longer than the time required to eliminate it. If it is assumed that the accumulation rate of an ice-age ice sheet lies in the range of 0.2 to 0.6 m./yr., it is found that the growth time of a large ice sheet is of the order of 15,000 to 30,000 yr. Ablation rates of to 2 m./yr. lead to shrinkage times of the order of 2,000 to 4,000 yr., provided ablation occurs over an appreciable area of the ice sheet.
The Glacial Lakes of Kumaon, India
Authors: Saxena H. B.
Published: September 2017

In the Kumaon region of the outer Himalayas there is a chain of lakes which, on the basis of various features, were previously thought to be of tectonic origin. A detailed geological study of this area carried out in June 1961 revealed the presence of morainic deposits in the vicinity of the lakes, and it is now considered that they are essentially of glacial origin.
Deformation in the Vicinity of Ice Divides
Authors: Raymond Charles F.
Published: September 2017

Numerical calculations by finite elements show that the variation of horizontal velocity with depth in the vicinity of a symmetric, isothermal, non-slipping ice ridge deforming on a flat bed is approximately consistent with prediction from laminar flow theory except in a zone within about four ice thicknesses of the divide. Within this near-divide zone horizontal shear strain-rate is less concentrated near the bottom and downward velocity is less rapid in comparison to the flanks. The profiles over depth of horizontal and vertical velocity approach being linear and parabolic respectively. Calculations for various surface elevation profiles show these velocity profile shapes are insensitive to the ice-sheet geometry.
Stability of Sheet Water Flow Under a Glacier
Authors: Weertman J. , Birchfield G. E.
Published: September 2017

Walder recently analyzed the initial instability of water flow in a sheet under a glacier that is produced by greater heat production in the flowing water and thus the larger rate of ice melting where a perturbation has increased the water sheet thickness. We have looked at the problem from the other presumed final state. We assume that instabilities have finally caused all the water to flow in channels (R-channels) at the bed. We investigated whether these channels can collect enough of the water that is produced by the geothermal heat and the heat sliding to remain in existence. When a basal shear stress is present, the distance out to which a channel can collect water is not that much greater than the channel radius itself. It is concluded that it is not likely for the channel to be able to collect appreciable amounts of water that is produced at the bed. Hence despite the indication that an instability initially might grow in a water sheet, this instability either cannot develop to the point when the water flow is primarily in channels or else the water flow alternates cyclically between a state primarily of sheet flow and a state of channel flow. It would appear that the channels that do exist under a glacier have their primary origin in the melt water from the upper surface that pours down moulins and thus is already channelized by the time it reaches the bed.
Investigations of Glacier Hydrological Systems using Dye Tracer Techniques: Observations at Pasterzengletscher, Austria
Authors: Burkimsher Marion
Published: September 2017

A comprehensive series of dye tracer tests was undertaken over two summers at Pasterzengletscher, Austria, and from these a number of important conclusions can be drawn. A lateral division of drainage on the lower tongue was proved, but this was not determined by the direction of oblique crevasses. Water from many moulins passed into two or more drainage courses, as shown by repeated patterns of multiple peaks on the time/concentration curves. The spatial pattern of travel times from different moulins on the tongue was complex, although it remained stable over time. Repeated tracer tests showed that throughflow velocities varied by up to an order of magnitude during a single day. Maximum velocities occurred at the time of peak discharge, and probably the large diurnal velocity variations are caused by changes in the proportion of the length which has channel-full pressure flow. However, seasonal velocity variations were much smaller, although changes in outflow discharge were larger than in the diurnal case. This gives strong support to the concept that channels adjust in size to the average water discharge passing through, and that these changes occur over a matter of days or a few weeks.
Isotope Stratification in High Mountain Glaciers: Examples from the Peruvian Andes and Himalaya
Authors: Grabczak Jerzy , Niewodniczański Jerzy , Różański Kazimierz
Published: September 2017

18O and deuterium content was measured in snow and ice samples collected from two crevasses on temperate glaciers high in the Andes and in the Himalaya. The results show that, due to intense exposure to sun, a significant part of the annual accumulation of snow is removed by melting and sublimation, the latter being predominant. There is strong empirical evidence that in natural conditions which are characteristic of both the glaciers studied sublimation of the snow cover can be approximated by the thermodynamic equilibrium process. The short-term fluctuations, though slightly moderated, and longer-term variations can still be observed in the deeper parts of the glaciers in spite of firnification of the snow.
A Whole-Field Interferometric Scheme for Measuring strain and Flow Rates of Glacier and Other Natural Surfaces
Authors: Cloud Gary , Conley Edgar
Published: September 2017

The flow of glacier ice is mapped using high-resolution photography and non-coherent-light speckle interferometry. Young’s fringe patterns result when a double-exposed photoplate image of the straining surface is illuminated by a narrow beam of coherent light. Geometry gives a relationship between the ice surface displacement vector and the interference fringe patterns. This displacement vector is corrected for rigid-body (camera) movement and projected onto the ice surface using topological maps. The strain during the time-lapse interval is thus known. Comparison with data acquired by surveying techniques at Nisqually Glacier, Washington, U.S.A., is limited because of small overlap of the surface studied. In the areas for which results can be compared, our experiments yield a flow of 0.6 m/d where conventional methods yield about 0.4 m/d.
Spatial Variations in Snow Stability Inferred from Artillery Control
Authors: Judson Arthur , M. King Rudy
Published: September 2017

Decisions on snow stability are strongly influenced by the presence of fresh avalanches. An analysis of 18 pairs of controlled avalanche paths in Colorado indicates most behave independently. The study supports the hypothesis that spatial variations in slope stability are common in unstable snow.
Systematic Unequal Dissection of Opposing Valley Sides
Authors: Liebling Richard S. , Scherp Horst S.
Published: September 2017

In the Nahoni Range of the northern Ogilvie Mountains, Yukon Territory, Canada, dissection channels are most markedly developed on valley sides facing the north and north-east. The extent of slope channelling is controlled by intensity of insolation and its influence on persistence of snow and ice. Upon the cooler north- and north-east-facing slopes, snow and ice remain well into midsummer; melt water is released over a long period and its discharge is restricted to narrow rivulets. In contrast, snow and ice on the warmer west- and south-facing slopes melt rapidly during the late spring months. The scree on these valley sides moves down-slope as a more or less uniform mass of water-saturated detritus.
VLF surface-impedance measurements for ice-depth mapping — an assessment of some commonly encountered interference effects
Authors: Thiel David V. , James Daniel , Johnson Peter
Published: September 2017

The effects on very low-frequency surface-impedence measurements of lateral variations commonly found in ice environments have been measured and modelled numerically using die quasi-static two-dimensional boundary-element method. Results indicate that surface-impedance measurements made in the vicinity of crevasses oriented perpendicular to the plane Of incidence, and those made in the vicinity of moraines and melt streams, can all show significant changes to the measured apparent resistivity. It is, therefore, misleading to use such measurements in the interpretation of ice depth.
Variation of snow, winter precipitation and winter air temperature during the last century at Nagaoka, Japan
Authors: Nakamura Tsutomu , Shimizu Masujiro
Published: September 2017

Reduced amounts of snow in the eight winters from 1986-87 to 1993-94 at Nagaoka, Japan, seem to be due to a winter air-temprature rise. The winter air temprature has shown cyclic varition gradual increase in the past 100years. The linear rate of the temperature rise in the past century was calculated as 1.35°C per 100 years. Both the maximum Snow depth and winter precipitation showed an inversely positive correlation with winter mean air temperature, The square of the statistical correlation coefficient r2 was calculated as 0.321 and 0.107. respectively. Statistically smoothed curves or the maximum snow depth and winter precipitation showed maximum values in 1940, Fluctuations in deviation of the maximum Snow depth showed smaller values than in precipitation. The minimum winter mean air temperature obtained from a 10 year moving average curve was found in 1942, and the deviation fom the climatic mean changed from negative to positive in 1949. The change in sign or the temperature deviation and the increase of the deviation may be attributable to global warming.
Controls on glacier surging in Svalbard
Authors: Hamilton Gordon S. , Dowdeswell Julian A.
Published: September 2017

The geographical distribution of surge-type glaciers worldwide displays a remarkably non-random pattern. Surge-type glaciers tend to be concentrated in certain glacierized areas and to be completely absent in others. This observation suggests that special conditions are required for surges to occur. However, the factors controlling the spatial occurrence of surge-type behaviour are not known. To investigate this problem we performed probability statistical analysis on a sample population of 615 glaciers in Svalbard. The probability that a glacier in the sample population is surge-type is 36.4%. Within the sampled area there is a spatial variation in the concentration of surge-type glaciers. Several geometric and environmental factors associated with glaciers in the sample population were measured and tested to determine if they are related to the probability of surging. Of the geometric factors tested (length, slope, elevation, orientation and presence or absence of tributaries), only glacier length is related to surging, with surge probability increasing with increasing length. Elevated probabilities of surging were also found for glaciers associated with sedimentary subglacial rocks and sub-polar thermal regimes. The distributions of related factors were used to predict the spatial distribution of surge-type glaciers. However, in each case the individual factors were unable to reproduce the observed pattern of surge-type glacier distribution.
An Experimental Study of the Motion of Ice Past Obstacles by the Process of Regelation
Authors: Morris E. M.
Published: September 2017

The results of regelation experiments, in which a single object is pulled through ice, cannot be applied directly to the problem of basal sliding in glaciers because the two systems have different geometries. When the force applied to a single object is small, impurities trapped in the regelation water-layer around the object inhibit the regelation process. At larger forces, above the Drake-Shreve transition point, impurities are shed in a trace behind the object. However, when ice moves over a series of obstacles a trace may exist above and below the transition point. The regelation velocity below the transition point is not reduced by the effect of trapped impurities. In an experiment in which brass cylingerrs of various cross-sections rotate in ice, the ratio between the expected regelation velocity, calculated using the basal-sliding theory of Nye, and the measured regelation velocity is 8±2, both above and below the transition point. The same ratio has been obtained by other workers with wires of similar thermal conductivity above the transition point. Measurements of température differences indicate that supercooling cannot be the main source of the unexpectedly low regelation velocities above the transition point.
On the use of Tensiometers in Snow Hydrology
Authors: Colbeck S. C.
Published: September 2017

The construction and use of snow-water tensiometers is gerscribed. Water pressure at the base of a shallow, Arctic snow-pack was measured to illustrate the response of the basal layer to water percolation. Water tension above an ice layer and water flux through the ice layer were measured in glacial snow. The gravity flow theory is used to explain the close agreement between these parameters. This suggests that the ice layer has little effect on the flow field and that gravity (rather than tension gradients) controls the flow. Further work on water tensions is neegerd to igerntify the role of tension gradients in ripening and shallow snow covers.
On the Origin of Ablation Hollows (Polygons) on Snow
Authors: Jahn Alfred , Kłapa Mieczyslaw
Published: September 2017

Ablation polygons on snow have been examined, mainly in the Tatra Mountains, both by field observation and by experiment. The polygons are initiated under peculiar climatic conditions—mostly when the melting of snow is somewhat slow and is accompanied simultaneously by the metamorphism of snow. A thick snow cover appears to be a prerequisite of this process. A detailed analysis of the problem of dirt concentration in snow, due to ablation, reveals the major role played by adhesion in this process. The concentration of dirt is due to lateral movement of the material and this is intrinsically related to the micro-elements of the snow surface.

The origin and development of ablation polygons do not depend on the presence of dirt in the snow; on the contrary, the process of dirt concentration and its effects are dependent on the evolution of polygonal forms.
Short Notes: Measured Beta Activity of Alaskan Firn
Authors: Wu T. H.
Published: September 2017

The measured β activities of firn samples from two sites on the Juneau Icefield are in good agreement with each other and with those of Greenland firn. A consistent pattern of β-activity variation can be identified far the fire layers from 1959 through 1962. The 1952–53 firn layer cannot be identified from the measured β activities.
The Heat and Mass Balance of Snow Dunes on the Central Antarctic Plateau
Authors: Weller G.
Published: September 2017

The heat-balance components of the faces of snow blocks were measured at “Plateau” station on the Antarctic plateau using micro-meteorological instrumentation. Heat-balance considerations and sublimation observations indicate considerable mass loss from the sloping snow surfaces during summer but little loss from horizontal surfaces. This process tends to level the irregularities of the snow surface. The conclusions are applicable to the snow dunes forming the general accumulation pattern on the Antarctic plateau.
Time-Dependent Intraglacier Structures
Authors: Goodman R. H.
Published: September 2017

Using time-domain pulsed radar, the intrastructure of a typical temperate glacier has been studied. Certain features have exhibited a rapid change in structure, and cannot be explained by density or ice characteristics of a stable nature. It is believed these time-dependent structures are related to the internal water system for glaciers.
On the Use of Telephone Poles for the Observation of Areal Snow-Depth Distribution
Authors: Kikuchi Katsuhiro
Published: September 2017

For the observation of areal snow-depth distribution over a wide area, such as the Ishikari Plain in Hokkaido, Japan, existing telephone poles were used in place of the snow scales. Telephone pole number plates (telephone poles in Japan have number plates) were photographed by a 35 mm camera with zoom lens ranging from 80 mm to 200 mm through the window of the observation vehicle. The snow depth was calculated by the ratios of the length of the number plates to the distance between the lower edge of the number plates and the snow surface. Since measurements by direct sounding using a rod as compared with the values by the above method showed a good coincidence with an accuracy of ± 10 cm, it was considered satisfactory for snow depth observation over a wide area.
The Mass Balance of the Sea Ice of the Arctic Ocean
Authors: Koerner R. M.
Published: September 2017

From data taken on the British Trans-Arctic Expedition it is calculated that 9% of the Arctic Ocean surface between the North Pole and Spitsbergen was hummocked or ridged ice, 17% was unridged ice less than a year old, 73% was unridged old ice and 0.6% was ice-free. The mode of 250 thickness measurements taken through level areas of old floes along the entire traverse lies between 2.25 and 2.75 m. The mean end-of-winter thickness of the ice is calculated to be 4.6 m in the Pacific Gyral and 3.9 m in the Trans-Polar Drift Stream. From measurements of the percentage coverage and thickness of the various ice forms, it is calculated that the total annual ice accumulation in the Arctic Ocean is equivalent to a continuous layer of ice 1.1 m thick. 47% of this accumulation occurs in ice-free areas and under ice less than 1 year old. 20% of the total ice production is either directly or indirectly related to ridging or hummocking. An ice-ablation rate of 500 kg m−2 measured on a level area of a multi-year floe is compared with the rate on deformed and ponded ice. Greatest melting occurs on new hummocks and least on old smooth hummocks. The annual balance of ice older than 1 year but younger than multi-year ice is calculated from a knowledge of ice-drift patterns and the percentage coverage of first-year ice. The same calculations give a mean-maximum drift period of 5 years for ice in the Trans-Polar Drift Stream and 16 years in the Pacific Gyral. It is calculated that for the period February 1968 to May 1969 the annual ice export was 5 580 km3.
Ice Calving into the Proglacial Generator Lake, Baffin Island, N.W.T., Canada
Authors: Holdsworth G.
Published: September 2017

The morphology of the Barnes Ice Cap margin at the proglacial Generator Lake is described. Types of calving that take place into the lake are discussed, particularly an observed calving in July 1970 when an ice-ramp of about 0.4 × 106 m3 volume broke off due to a rise in lake level. Bending analyses which throw some light on the calving mechanism are presented.
Flow of a Valley Glacier with a Solid Friction Law
Authors: Reynaud L.
Published: September 2017

Friction on the bed is assumed to obey Coulomb’s law of solid friction in the presence of interstitial pressure (Lliboutry, 1968). According to this, the friction is a maximum at certain places in the bottom of the valley. Assuming Glen’s non-linear creep law, the steady-state flow of ice along a regular cylindrical channel of parabolic section has been calculated. The results reproduce to high accuracy the distribution of velocity measured on the Athabasca Glacier (Raymond, 1971).
Snow-Fence Experiments in Alpine Areas
Authors: Martinelli M.
Published: September 2017

Snow fences built up-wind of natural snowdrifts at four alpine sites in the Colorado Rocky Mountains changed snow accumulation appreciably. The 3 m tall fences increased the amount of snow at three sites but decreased it at the fourth. At two of the three sites where snow was increased, there was no change in melt rate, so the additional snow prolonged the melt period 1–3 weeks. Fences most successfully augmented natural snow accumulation at sites with level or gently sloping terrain down-wind from the accumulation site. Between 15 and 30 m of fence was needed to produce an extra 1000 m3 of water equivalent in the snowfields at the beginning of the melt season. Fences of the type described here, if properly located, are a means of increasing summer stream flow from alpine areas.
The Yield of Avalanche Snow at Rogers Pass, British Columbia, Canada
Authors: Schaerer Peter
Published: September 2017

The annual mass of snow moved by avalanches was observed at 45 avalanche paths over a period of 19 years by measuring the volume and density of each individual avalanche. Several other methods to estimate the total annual avalanche mass were applied but they were found less efficient owing to inaccuracy and difficulties in timing.

For the data set, the yield ratio, i.e. the percentage of snow removed annually by avalanches, had a mean value of 11.2% and a 30 year maximum of 30.9%. The yield ratio varied strongly among avalanche paths and yearly, and could not be explained satisfactorily. The exposure to wind, inclination of the avalanche track, control by artillery, and the winter weather can all have an influence on the value of the parameter.

The temporal variability of avalanche yield is erratic but weather patterns frequently associated with high or low yield ratios could be identified. High values are usually associated with large avalanches triggered by major weather events in the late part of the winter.
A One-Dimensional Finite-Element Model for Two-Dimensional Glacier Flow
Authors: Stolle D. F. E.
Published: September 2017

A description of the reduction of two-dimensional equilibrium equations to one-dimensional form via the Kantorovich method is given. An appropriate interpolation function is obtained by relating basal shear stress to sliding velocity and integrating the constitutive model through the depth of ice. An example is presented which demonstrates the ability of the numerical model to effect solutions which are in good agreement with those obtained via full two-dimensional finite-element models; however, at a small fraction of computational and data input efforts. The technique described for the reduction of the equilibrium equations can also be used to convert three-dimensional stress equilibrium to two-dimensional form.
A Comparison Between the Theoretical and the Measured Long Profile of the Unteraar Glacier
Authors: Nye J. F.
Published: September 2017

The measurements by seismic sounding of the long profile of the Unteraar Glacier reported by Mercanton and Renaud are compared with theoretical calculations. By taking the valley to be a cylinder of parabolic cross-section a theoretical curve for the surface is deduced which depends on one unknown parameter only, the average shear stress on the bed. If this parameter is given the value 0.77 × 106 dynes/cm.2 the theoretical curve agrees well with the measurements.
Glacier Wasting and Retreat in the Southern ALPS of New Zealand
Authors: Harrington H. J.
Published: September 2017

Down-wasting has affected southern glaciers in New Zealand later than northern glaciers under the influence of a southward rising snow line which is attributed to a southerly shift in prevailing wind belts. Evidence from the Hooker Glacier indicates that the present period of wasting is the fourth of a series which began about 200 years ago.

As the firn line rises a glacier is planed in the ablation zone so that successive surfaces are parallel to the original surface, which shows that ablation is more active for a short distance below the fern line than near the terminal face. A period of accelerated terminal retreat can result from parallel down-wasting without a correlative acceleration in the rate of climatic change.
Kinematic analysis of isokinetic knee flexor and extensor tests
Authors: Alt Tobias , Severin Jannik , Nodler Yannick T. , Horn Dennis , El-Edrissi Omar , Knicker Axel J. , Strüder Heiko K.
Published: September 2017

BACKGROUND:

Isokinetic dynamometry is widely considered the gold standard in mechanical muscle performance testing. Invariably, the moment-position raw data obtained from the dynamometer is directly analysed although kinematic inaccuracies may inherently exist.

OBJECTIVE:

To quantify the differences between two processing methods of isokinetic raw data: one based on the device’s own software and one using a hybrid kinematic procedure.

METHODS:

Seventy-six healthy male participants performed unilateral concentric knee extensor (Qcon) (90[Formula: see text] ROM) and eccentric knee flexor (Hecc) tests (110[Formula: see text] ROM) at 150[Formula: see text]/s. The knee angles were recorded by two high-speed cameras per body side.

RESULTS:

Compared to isokinetic data, kinematic analysis revealed reduced knee ROM of 17[Formula: see text] for Qcon and of 21[Formula: see text] for Hecc. Thus, the mean ‘isokinetic’ angular velocity declined to 121 and 122[Formula: see text]/s, respectively. The angles of peak moment changed significantly ([Formula: see text]5[Formula: see text] for Qcon, [Formula: see text]20[Formula: see text] for Hecc). Contractional work decreased ([Formula: see text]20%) only for Qcon. The moments and angles derived from analysis of the DCR at the equilibrium point (DCRe) rose by 7% and 20% respectively when the isokinetic raw data were linked with kinematic data. The comparison of both processing methods revealed very high (R[Formula: see text] [Formula: see text] 91%) and high (R[Formula: see text] [Formula: see text] 69%) relationships for DCRe moments and angles.

CONCLUSIONS:

Isokinetic raw data comprise kinematic inaccuracies caused by axis misalignment, evasive movements and anatomical features. Although a hybrid kinematic procedure is more time-consuming, it may enable a more valid clinical interpretation of the test findings.
Cannon Ball Diagnosis and Management in a Flight Attendant Candidate
Authors: Zerrik Meryem , Echchachoui Houda , Iloughmane Zakaria , El’mhadi Choukri , Elkhader Salaheddine , Benaissa Laila , Chemsi Mohamed
Published: September 2017

BACKGROUND: ''Cannon ball'' opacities on chest X-rays are a common manifestation of hematogenous dissemination of a malignant tumor in the lungs. They indicate an advanced stage of disease with a very grim prognosis in terms of cure and survival. In aerospace medicine, this aspect
means the patient is unfit for flight duties. Nonmetastatic etiologies of pulmonary nodules are rare. We report a case of cannon ball opacities discovered fortuitously during an admission visit.CASE REPORT: A 23-yr-old flight attendant candidate came to the Aeromedical Expertise
Center of the Military Hospital in Rabat for medical evaluation. He had no previous medical comorbidities and was asymptomatic. The physical examination was unremarkable. Chest X-ray revealed multiple poorly defined pulmonary nodular opacities, without mediastinal widening. After excluding
other possibilities, such as infection or malignancy, the diagnosis of a pseudotumoral form of thoracic sarcoidosis was established by clinical and radiological findings, supported by histopathologic analysis.DISCUSSION: The pseudotumoral form of sarcoidosis is rare. It is usually
seen in young people who are asymptomatic. Chest X-ray shows bilateral nodular opacities of different sizes. CT scan shows snowballs, which may or may not manifest with air bronchogram or mediastinal lymph nodes. Laboratory investigations are nonspecific. Pulmonary functions are normal or
may show a restrictive pattern. Evolution is spontaneously favorable and does not require any treatment in asymptomatic patients. Aeromedical fitness in sarcoidosis disease depends on several conditions. This observation affirms the benefit of routine chest X-ray during medical evaulations
to detect possible entities that may endanger flight safety.Zerrik M, Echchachoui H, Iloughmane Z, El’mhadi C, Elkhader S, Benaissa L, Chemsi M. Cannon ball diagnosis and management in a flight attendant candidate. Aerosp Med Hum Perform. 2017; 88(10):958–961.
Pneumatic Multi-Pocket Elastomer Actuators for Metacarpophalangeal Joint Flexion and Abduction-Adduction
Authors: Tarvainen Tapio , Yu Wenwei
Published: September 2017

During recent years, interest has been rising towards developing fluidic fiber-reinforced elastomer actuators for wearable soft robotics used in hand rehabilitation and power-assist. However, they do not enable finger abduction-adduction, which plays an important role in activities of daily living, when grasping larger objects. Furthermore, the developed gloves often do not have separate control of joints, which is important for doing various common rehabilitation motions. The main obstacle for the development of a fully-assisting glove is moving a joint with multiple degrees of freedom. If the functions are built into the same structure, they are naturally coupled and affect each other, which makes them more difficult to design and complex to control than a simple flexion-extension actuator. In this study, we explored the key design elements and fabrication of pneumatic multi-pocket elastomer actuators for a soft rehabilitation glove. The goal was to gain more control over the metacarpophalangeal joint’s response by increasing the degree of actuation. Three main functional designs were tested for achieving both flexion and abduction-adduction. Five prototypes, with four different actuator geometries and four different reinforcement types, were designed and fabricated. They were evaluated by recording their free motion with motion capture and measuring their torque output using a dummy finger. Results showed the strengths and weaknesses of each design in separating the control of the two functions. We discuss the different improvements that are needed in order to make each design plausible for developing an actuator that meets the requirements for full assist of the hand’s motions. In conclusion, we show that it is possible to produce multi-pocket actuators for assisting MCP joint motion in both flexion and abduction-adduction, although coupling between the separate functions is still problematic and should be considered further.
Stomatal and Non-Stomatal Turbulent Deposition Flux of Ozone to a Managed Peatland
Authors: El-Madany Tarek , Niklasch Katharina , Klemm Otto
Published: September 2017

Ozone is a key trace gas in the troposphere; because it is a greenhouse gas, it is very reactive, and it is potentially toxic to humans, fauna, and vegetation. The main sink processes for ozone are chemical reactions and the turbulent deposition flux to the earth’s surface. The deposition process itself is rather complex: The interactions between co-varying drivers such as the tropospheric ozone concentration, turbulence, and chemical reactions are not well understood. In the case of ozone deposition to vegetation, another aspect that must be studied is the role of stomatal regulation for a wide range of conditions. Therefore, we measured turbulent deposition fluxes of ozone with the eddy covariance technique during the peak of the growing season in 2014 over a managed, rewetted peatland in NW Germany. The deposition flux was large during the day (up to −15 nmol m−2 s−1) and relatively small during the night (between −1 and −2 nmol m−2 s−1). Flux partitioning by applying the surface resistance analogy and further analysis showed that the stomatal uptake was smaller than non-stomatal deposition. The correction of stomatal conductance with the gross primary production (GPP) improved the estimation of day- and nighttime stomatal deposition fluxes. Statistical analysis confirmed that the friction velocity (u*) was the single most important driver of non-stomatal ozone deposition and that relationships with other environmental drivers are not linear and highly variable. Further research is needed to develop a better process understanding of non-stomatal ozone deposition, to quantify the role of surface deposition to the ozone budget of the atmospheric boundary layer, and to estimate uncertainties associated with the partitioning of ozone deposition into stomatal and non-stomatal fluxes.
Halide-Enhanced Catalytic Activity of Palladium Nanoparticles Comes at the Expense of Catalyst Recovery
Authors: Bouleghlimat Azzedine , Othman Mazin , Lagrave Louis , Matsuzawa Soichiro , Nakamura Yoshinobu , Fujii Syuji , Buurma Niklaas
Published: September 2017

In this communication, we present studies of the oxidative homocoupling of arylboronic acids catalyzed by immobilised palladium nanoparticles in aqueous solution. This reaction is of significant interest because it shares a key transmetallation step with the well-known Suzuki-Miyaura cross-coupling reaction. Additives can have significant effects on catalysis, both in terms of reaction mechanism and recovery of catalytic species, and our aim was to study the effect of added halides on catalytic efficiency and catalyst recovery. Using kinetic studies, we have shown that added halides (added as NaCl and NaBr) can increase the catalytic activity of the palladium nanoparticles more than 10-fold, allowing reactions to be completed in less than half a day at 30 °C. However, this increased activity comes at the expense of catalyst recovery. The results are in agreement with a reaction mechanism in which, under conditions involving high concentrations of chloride or bromide, palladium leaching plays an important role. Considering the evidence for analogous reactions occurring on the surface of palladium nanoparticles under different reaction conditions, we conclude that additives can exert a significant effect on the mechanism of reactions catalyzed by nanoparticles, including switching from a surface reaction to a solution reaction. The possibility of this switch in mechanism may also be the cause for the disagreement on this topic in the literature.
Assessing Autophagy in Sciatic Nerves of a Rat Model that Develops Inflammatory Autoimmune Peripheral Neuropathies
Authors: Brun Susana , Schall Nicolas , Jeltsch-David Hélène , Sèze Jérôme de , Muller Sylviane
Published: September 2017

The rat sciatic nerve has attracted widespread attention as an excellent model system for studying autophagy alterations in peripheral neuropathies. In our laboratory, we have developed an original rat model, which we used currently in routine novel drug screening and to evaluate treatment strategies for chronic inflammatory demyelinating polyneuropathy (CIDP) and other closely related diseases. Lewis rats injected with the S-palmitoylated P0(180-199) peptide develop a chronic, sometimes relapsing-remitting type of disease. Our model fulfills electrophysiological criteria of demyelination with axonal degeneration, confirmed by immunohistopathology and several typical features of CIDP. We have set up a series of techniques that led us to examine the failures of autophagy pathways in the sciatic nerve of these model rats and to follow the possible improvement of these defects after treatment. Based on these newly introduced methods, a novel area of investigation is now open and will allow us to more thoroughly examine important features of certain autophagy pathways occurring in sciatic nerves.
Comparison of Flipped Model to Traditional Classroom Learning in a Professional Pharmacy Course
Authors: McCabe Colleen , Smith Megan , Ferreri Stefanie
Published: September 2017

The flipped classroom is an approach to incorporate active learning that is being used in secondary education, higher education, and professional schools. This study investigates its impact on student learning and confidence in a professional degree program course. A quasi-experimental study was conducted to evaluate pharmacy students enrolled in a semester-long didactic traditional classroom course compared to students learning the same material using a flipped model through online self-study modules in a hands-on experiential learning course. Before and after each learning experience, students of each group completed a 16-item knowledge assessment on four topic areas and rated their level of confidence with each topic area on a Likert scale. There was a significant difference in knowledge with students in the traditional course scoring higher than students using flipped approach in the experiential course. Furthermore, the flipped experiential course students did not improve assessment scores from pre-test to post-test. For confidence rating, the traditional course group ranked confidence higher than the flipped experiential group for all topics. These findings challenge the notion that the flipped model using self-study in an experiential setting can be a substitution for didactic delivery of pharmacy education.
Modeling Polarized Emission from Black Hole Jets: Application to M87 Core Jet
Authors: Mościbrodzka Monika
Published: September 2017

We combine three-dimensional general-relativistic numerical models of hot, magnetized Advection Dominated Accretion Flows around a supermassive black hole and the corresponding outflows from them with a general relativistic polarized radiative transfer model to produce synthetic radio images and spectra of jet outflows. We apply the model to the underluminous core of M87 galaxy. The assumptions and results of the calculations are discussed in context of millimeter observations of the M87 jet launching zone. Our ab initio polarized emission and rotation measure models allow us to address the constrains on the mass accretion rate onto the M87 supermassive black hole.
Transcription Factors Responding to Pb Stress in Maize
Authors: Zhang Yanling , Ge Fei , Hou Fengxia , Sun Wenting , Zheng Qi , Zhang Xiaoxiang , Ma Langlang , Fu Jun , He Xiujing , Peng Huanwei , Pan Guangtang , Shen Yaou
Published: September 2017

Pb can damage the physiological function of human organs by entering the human body via food-chain enrichment. Revealing the mechanisms of maize tolerance to Pb is critical for preventing this. In this study, a Pb-tolerant maize inbred line, 178, was used to analyse transcription factors (TFs) expressed under Pb stress based on RNA sequencing data. A total of 464 genes expressed in control check (CK) or Pb treatment samples were annotated as TFs. Among them, 262 differentially expressed transcription factors (DETs) were identified that responded to Pb treatment. Furthermore, the DETs were classified into 4 classes according to their expression patterns, and 17, 12 and 2 DETs were significantly annotated to plant hormone signal transduction, basal transcription factors and base excision repair, respectively. Seventeen DETs were found to participate in the plant hormone signal transduction pathway, where basic leucine zippers (bZIPs) were the most significantly enriched TFs, with 12 members involved. We further obtained 5 Arabidopsis transfer DNA (T-DNA) mutants for 6 of the maize bZIPs, among which the mutants atbzip20 and atbzip47, representing ZmbZIP54 and ZmbZIP107, showed obviously inhibited growth of roots and above-ground parts, compared with wild type. Five highly Pb-tolerant and 5 highly Pb-sensitive in maize lines were subjected to DNA polymorphism and expression level analysis of ZmbZIP54 and ZmbZIP107. The results suggested that differences in bZIPs expression partially accounted for the differences in Pb-tolerance among the maize lines. Our results contribute to the understanding of the molecular regulation mechanisms of TFs in maize under Pb stress.
Carbonic Anhydrase Inhibition and the Management of Hypoxic Tumors
Authors: Supuran Claudiu T.
Published: September 2017

Hypoxia and acidosis are salient features of many tumors, leading to a completely different metabolism compared to normal cells. Two of the simplest metabolic products, protons and bicarbonate, are generated by the catalytic activity of the metalloenzyme carbonic anhydrase (CA, EC 4.2.1.1), with at least two of its isoforms, CA IX and XII, mainly present in hypoxic tumors. Inhibition of tumor-associated CAs leads to an impaired growth of the primary tumors, metastases and reduces the population of cancer stem cells, leading thus to a complex and beneficial anticancer action for this class of enzyme inhibitors. In this review, I will present the state of the art on the development of CA inhibitors (CAIs) targeting the tumor-associated CA isoforms, which may have applications for the treatment and imaging of cancers expressing them. Small molecule inhibitors, one of which (SLC-0111) completed Phase I clinical trials, and antibodies (girentuximab, discontinued in Phase III clinical trials) will be discussed, together with the various approaches used to design anticancer agents with a new mechanism of action based on interference with these crucial metabolites, protons and bicarbonate.