bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Century of Library Support for Teacher Education in Calgary
Authors: Brydges Barbara 
Published: September 2017

This paper traces the century-long history of a library that has served teacher preparation programs in Calgary, Alberta, since 1909. It looks at how this library’s role and collections adapted to shifting notions of what constituted good teacher education and changing economic circumstances. In recounting this history, the paper examines the historical circumstances that created a separate education library at the University of Calgary and how issues of group and professional identity contributed to its continuing existence. The various themes which emerge may be common to many North American education libraries.
Guest Editorial
Authors: Ramachandran Hema , Lanham Erin 
Published: September 2017

This issue of Education Libraries, which is dedicated to the ongoing, timely, and important topic of information literacy in the workplace, showcases presentations from two sessions sponsored by the Education and Engineering Divisions at the 2010 SLA Annual Conference in New orleans http://www.sla.org/content/events/confpresentations/2010.cfm. The first part of the program provided an overview of the issues from key researchers in the field; the second part was a panel of academic and corporate engineering librarians discussing the challenges they face in imparting information literacy. [...]
21st Century Workforce Initiatives: Implications for Information Literacy Instruction in Academic Libraries
Authors: Leavitt Laura L. 
Published: September 2017

The discussion that follows is designed to expose the reader to a selection of educational reform initiatives that fall under the “21st Century Workforce” umbrella. The aims of these initiatives are quite harmonious with the overarching goals of librarianship and the opportunities for librarians to become involved and to demonstrate leadership in this arena are plentiful. The author’s efforts to incorporate information literacy principles and to encourage critical thinking in a graduate level organizational behavior class – in light of these initiatives and in response to employer feedback – are also discussed. It is hoped that the followinginformation will inspire librarians to explore the initiatives further and to re-examine current information literacy and instruction efforts within this larger framework.
Detecting Earning Management: Deferred Taxes vs Accruals: A Pakistani Perspective
Authors: Shanwari Imran , Shah S. M. Aamir 
Published: September 2017

Objective: Earning Management has been one of the major areas of accounting research which has received a great attention in the past and also quite recently. Detecting earning management has always been one of the major areas of concern for the researchers. Earnings Management is pervasive. There are a number of models available to Detect and measure the earnings management activity.
Methodology: The accrual models are the most used models to proxy the discretionary accruals and the earnings management. The effectiveness of the accrual models is somewhat skeptical at times when researchers found some inconsistencies in results while using the accrual models. The researchers are still finding some better and effective model that can be used to better measure and capture the earnings management activity. The focus of this study is to find out as to whether a deferred tax as compared to accrual models is more useful in measuring or detecting the earnings management in Pakistani perspective. The study is based on the Pakistani companies listed on the Karachi Stock Exchange (KSE). This study is expected to be an addition to the existing research as to whether the models used for detecting earnings management through deferred taxes by Philips et al (2003) are also applicable to Pakistani Scenario which is a developing country. The study used Probit Regression Model with pooled cross sectional data to measure the usefulness of both; accruals and deferred taxes (the proxies) used as better measure for Earnings management.
Results: The results of the study are inconsistent with the Philips et al. (2003) study. Based on this study it is concluded that deferred tax is not incrementally useful along with the other accrual measure. The accruals models show significant results and are more powerful metric to detect earnings management as compared to the deferred taxes in Pakistan.
Accumulation and hoar effects on microwave emission in the Greenland ice-sheet dry-snow zones
Authors: Abdalati Waleed , Steffen Konrad 
Published: September 2017

AbstractThe relationships between accumulation and microwave emissivity in the dry-snow regions of the Greenland ice sheet are studied with special focus on hoar formation. With the use of a discrete-ordinate radiative-transfer model, the relative contributions of hoar and accumulation to microwave omission are examined. The results show that the link between microwave emission and accumulation rates in the dry-snow area of the Greenland ice sheet is significant; however, the emissivity is also dependent on the extent of hoar development. As a result, accumulation estimates based on passive microwave observations in the low-accumulation dry-snow areas will require successful parameterization of hoar formation. Furthermore, the increasing Tb, trends that were observed during the 1980s, which have been hypothesized to be related to accumulation changes, may be strongly related to variations in hoar development. Other possible explanations for these observed trends, such as slight surface melt or atmospheric conditions, are also discussed.
Glaciohydraulic supercooling: a freeze-on mechanism to create stratified, debris-rich basal ice: I. Field evidence
Authors: Lawson Daniel E. , Strasser Jeffrey C. , Evenson Edward B. , Alley Richard B. , Larson Grahame J. , Arcone Steven A. 
Published: September 2017

AbstractDebris-laden ice accretes to the base of Matanuska Glacier, Alaska, U.S.A., from water that supercools while flowing in a distributed drainage system tip the adverse slope of an overdeepening. Frazil ice grows in the water column and forms aggregates, while other ice grows on the glacier sole or on substrate materials. Sediment is trapped by this growing ice, forming stratified debris-laden basal ice. Growth rates of >0.l ma−1 of debris-rich basal ice are possible. The large sediment fluxes that this mechanism allows may have implications for interpretation of the widespread deposits from ice that flowed through other overdeepenings, including Heinrich events and the till sheets south of the Laurentian Great Lakes.
Modeling the signature of a transponder in altimeter return data and determination of the reflection surface of the ice cap near the GRIP camp, Greenland
Authors: Haardenog-Pedersen G. , Keller K. , Tscherning C. C. , Gundestrup N. 
Published: September 2017

AbstractUsing an active transponder with the ERS-I and ERS-2 radar altimeters, the distance to the satellite was measured at a location close to the GRIP site, Greenland, at an altitude of 3.2 km. The measurement was executed while the transponder was in the “ice-tracking mode”. It includes a bias due to the propagation delay. The location of the transponder was determined using the global positioning system.The transponder signal was modeled and the distance from the altimeter to the effective reflection point of the transponder was determined. Since the transponder was located within 1 km of the ground tracks, the measurement was corrected for this offset. A correction was also done for the surface slope, resulting in the distance (plus bias) to the closest sub-satellite point on the surface of the (compact) snow.The transponder signal was then removed from the radar altimeter waveform, enabling the determination of the distance (plus bias from the altimeter to the first reflective surface within the snow. The différence between this distance and that obtained using the transponder was < 2 m. This shows that the surface which gives rise to the first return of the reflection agrees with the surface of the (compact, dry) snow at this high-altitude location. This is an important result to be used when studying ice-cap topography using satellite radar altimetry.
Glacial retreat and its geomorphologic effects on Mexico’s active volcanoes, 1994–95
Authors: Palacios David , Marcos Javier De 
Published: September 2017

AbstractThe northern slopes of Mexico’s great, active stratovolcanoes, Popocatépetl (5450 m.a.s.l.) and Pico de Orizaba (5700 m a.s.l.), are covered by glaciers. This paper analyzes the retreat of the glaciers between February 1994 and October 1995, and its geo-morphological consequences. The results discussed are a continuation of research conducted on the volcanoes up to 1994. Although the glaciers retreated a great deal during the 1980s and early 1990s, the process accelerated from 1994 to 1995. The heavy erosion that had been observed on the deglaciated walls of the volcanoes during these decades increased as the glaciers retreated. Sediments originating from material loosened from the exposed lateral walls added to the supraglacial layer. Temperature readings taken from boreholes made in the glaciers indicated that ablation had been reduced as a result of the insulating effects of the debris mantle. This allowed widespread formation of deposits that buried ice in areas where the glacier had already disappeared. These results confirmed the conclusions of earlier studies that deglaciation of stratovolcanoes has resulted in the acceleration of slope processes and the formation of buried ice deposits.
Crevasse patterns and the strain-rate tensor: a high-resolution comparison
Authors: Harper J. T. , Humphrey N. F. , Pfeffer W. T. 
Published: September 2017

AbstractValues of the strain-rate tensor represented at a 20 m length scale are found to explain the pattern and orientation of crevasses in a 0.13 km2 reach of Worthington Glacier, Alaska, U.S.A. The flow field of the reach is constructed from surveyed displacements of 110 markers spaced 20-30 m apart. A velocity gradient method is then used to calculate values of the principal strain-rate axes at the nodes of a 20 m x 20 m orthogonal grid. Crevasses in the study reach are of two types, splaying and transverse, and are everywhere normal to the trajectories of greatest (most tensile) principal strain rate. Splaying crevasses exist where the longitudinal strain rate (x) is ≤ 0 and transverse crevasses are present under longitudinally extending flow (i.e. x > 0). The orientation of crevasses changes in the down-glacier direction, but the calculated rotation by the flow field does not account for this change in orientation. Observations suggest that individual crevasses represent local values of the regional flow field and are transient on the time-scale of 1-2 years; they are not persistent features that are translated and rotated by flow. Crevasse patterns are thus found to be a useful tool for mapping the strain-rate tensor in this reach of a temperate valley glacier.
Altitudinal gradient of mass-balance sensitivity to climatic change from 18 years of observations on glacier d’Argentière, France
Authors: Vallon M. , Vincent C. , Reynaud L. 
Published: September 2017

AbstractAssessment of the contribution of small glaciers to sea-level rise or the reconstruction of past glacial mass balance requires knowledge of mass-balance sensitivity to climatic variations. The aim of this paper is to clarify this relation. The mass-balance fluctuations analyzed from measurements on glacier d’Argentière, Mont Blanc massif, France, between 1850 and 2700 m a.s.l. were compared with climatic variations at a nearby meteorological station. Statistical study of the data shows that: (1) the annual mass-balance fluctuations are dependent on elevation, and (2) the mass-balance sensitivity to temperature decreases with altitude and diverges from current model results. Consequences of a temperature variation of 1°C for global volume variations are significant. A simple calculation on glacier des Bossons, Mont Blanc massif, France, shows that the sensitivity from the model can lead to volume variations twice as high as results compatible with our observations.
Satellite gravity and the mass balance of the antarctic ice sheet
Authors: Bentley C. R. , Wahr J. M. 
Published: September 2017

AbstractChanges in the Earth’s gravity field with time have important applications to a broad range of disciplines. Any process that involves a large enough horizontal redistribution of mass, either within the Earth or on or above its surface, is potentially detectable. In particular, when ice sheets grow or shrink, gravity changes as mass is redistributed in the solid earth and between the oceans and the ice sheets. The sources of global sea-level rise (about 2 mm a−1 over the last century) and in particular the contribution of the Antarctic ice sheet thereto are not well understood. Gravity measurements can help to diminish this uncertainty.The technology currently exists to measure gravity with high accuracy by a dual-satellite mission in which the distance between the satellites is precisely monitored. We estimate from recent studies that temporal changes in the gravity field as determined by a satellite gravity mission lasting 5 years at an orbital height of 400 km would be sensitive to changes in the overall mass of the Antarctic ice sheet to a precision corresponding to better than 0.01 mm a−1 of sea-level change. However, the effects of three other phenomena that could each produce a temporally varying gravity signal with characteristics comparable to that caused by a change in Antarctic ice—postglacial rebound, inter-annual variability in snowfall, and atmospheric pressure trends — also need to be evaluated. Postglacial rebound could be partly separated from ice-mass changes with the aid of global positioning system campaigns and numerical models of rebound that use improved determinations of mantle viscosity also provided by the gravity mission. Determination of inter-annual ice-mass changes will be aided by measurements of moisture-flux divergence around the perimeters of the ice sheets and direct observations of inter-annual changes by the gravity satellite itself. The removal of pressure effects over Antarctica will become more effective as the number of automatic weather stations in the interior of the continent increases.Even after corrections are made for these factors, the uncertainties they cause limit the accuracy in the détermination of the contribution of the Antarctic ice sheet to sea-level change to about 0.5 mm a−1. However, there is a strong complementarity between gravity measurements and the surface-height measurements that will be produced by NASA’s laser altimeter mission early next century. Together, they should be able to determine that contribution to an accuracy of about 0.1 mm a−1.
A 1 year record of global radiation and albedo in the ablation zone of Morteratschgletscher, Switzerland
Authors: Oerlemans J. , Knap W. H. 
Published: September 2017

AbstractWe analyse data on solar radiation measured with an automatic weather station on Morteratschgletscher, Switzerland, for the period 1 October 1995–30 September 1996. The station is in the lower ablation zone. Due to shading by surrounding mountains and atmospheric attenuation, only 49% of the annual extraterrestrial irradiance (mean: 292 W m−2) reaches the glacier surface. About 48% of this is absorbed at the surface (mean: 79 W m−2; annual albedo of 0.53).We present a simple albedo scheme for use in glacier mass-balance models. We fit the model to the 1 year dataset by optimizing five control parameters (optimal values in brackets): albedo of snow (0.75), albedo of firn (0.53), albedo of ice (0.34), e-folding constant for effect of ageing on snow albedo (21.9 days) and e-folding constant for effect of snow depth on albedo (3.2 cm). The input consists of daily albedo, snow depth and dates of snowfall events. The correlation coefficient between observed and simulated albedo is 0.931, the corresponding rms difference being 0.067.
Geometric evolution and ice dynamics during a surge of Bakaninbreen, Svalbard
Authors: Murray Tavi , Dowdeswell Julian A. , Drewry David J. , Frearson Ian 
Published: September 2017

AbstractBakaninbreen, Svalbard, started surging in 1985 and developed a steep surge front where fast-moving ice impinged on stagnant non-surging ice. This front, which was 20- 25 m high in 1985, became a steep and heavily crevassed feature about 60 m high. The surge continued through 1986-95. Annual surge-front propagation rate was 1.0 1.8 km a−1 during 1985-89; this rate dropped considerably during 1989 95 and the front became less steep. Front propagation occurred largely by longitudinal compression and vertical extension of the ice and the effects of over-riding appear minor. Ice velocities were slower than the average propagation rate of the front. The surge affected Bakaninbreen in four zones: (1) Upper region where extensive flow, fast propagation rates and negative vertical strain occurred, resulting in widespread crevassing and stranded blocks tens of metres above the post-surge ice surface, (2) Mid-glacier region where initial strong compression was associated with ice thickening which started before the arrivai of the surge front. Horizontal strain rates were very low but vertical strain rates were tip to 300 mmd−1. As (he front passed, the horizontal velocity increased and about 500 m behind it became extensive. Negative vertical strain and ice down-draw occurred as ice velocities dropped, (3) Surge front where ice velocity was high but vertical strain remained positive associated with compression. (4) Lower region below the iront where only compression occurred, resulting in the formation of a fore bulge, a thickening of the ice of up to 50 m above pre-surge levels. The fore bulge affected the whole 1.7 km below the, now halted, surge front. The glacier has not advanced, Bakaninbreen’s surge was characterized by a long active phase, approximately 10 years, low ice velocities and low basal shear stresses compared to glaciers in lower latitudes, and an indistinct surge termination.
Isotopic diffusion in polar firn: implications for interpretation of seasonal climate parameters in ice-core records, with emphasis on central Greenland
Authors: Cuffey Kurt M. , Steig Eric J. 
Published: September 2017

AbstractIf it were possible to properly extract seasonal information from ice-core isotopic records, paleoclimate researchers could retrieve a wealth of new information concerning the nature of climate changes and the meaning of trends observed in ice-core proxy records. It is widely recognized, however, that the diffusional smoothing of the seasonal record makes a “proper extraction" very difficult. In this paper, we examine the extent to which seasonal information (specifically the amplitude and shape of the seasonal cycle) is irrecoverably destroyed by diffusion in the firn. First, we show that isotopic diffusion firn is reasonably well understood. We do this by showing that a slightly modified version of the Whillans and Grootes (1985) theory makes a tenable a priori prediction of the decay of seasonal isotopic amplitudes with depth at the GISP2 site, though a small adjustment to one parameter significantly improves the prediction. Further, we calculate the amplitude decay at various other ice-core sites and show that these predictions compare favorably with published data from South Pole and locations in southern and central Greenland and the Antarctic Peninsula. We then present numerical experiments wherein synthetic ice-core records are created, diffused, sampled, reconstituted and compared to the original. These show that, alter diffusive mixing in the entire fini column, seasonal amplitudes can be reconstructed to within about 20% error in central Greenland but that all information about sub-annual signals is permanently lost there. Furthermore, most of the error in the amplitude reconstructions is due to the unknowable variations in the sub-annual signal. Finally, we explore how these results can be applied to other locations and suggest that Dye 3 has a high potential for meaningful seasonal reconstructions, while Siple Dome has no potential at all. An optimal ice-core site for seasonal reconstructions has a high accumulation rate and a low temperature.
The stability of a viscous till sheet coupled with ice flow, considered at wavelengths less than the ice thickness
Authors: Hindmarsh Richard C. A. 
Published: September 2017

AbstractA perturbation method is used to analyse the stability of a thin till layer overlain by a deep ice layer. Ice is modelled as a linearly viscous fluid, while the till viscosity has power-law dependence on stress and effective pressure. A linearized set of equations yields descriptions of the coupling of the ice flow with the sediment flow and reveals parameter ranges where the till-perturbation amplitude can grow. This sheet-flow instability is an essential part of any theory of drumlin formation and shows that viscous models of till have the ability to explain typical deforming-bed features. This is of great significance for large-scale ice-sheet modelling.
Mass balance of glaciers other than the ice sheets
Authors: Cogley J. Graham , Adams W. P. 
Published: September 2017

AbstractSmall glaciers appear to have been at equilibrium or shrinking very slightly during 1961–90, according to analysis of an essentially complete set of published measurements. Simple calculations give an average annual mass balance of –195 ± 59 mm a−1 (water equivalent) but this is too low because of systematic errors. Neglect of internal accumulation is responsible for some tens of millimeters of underestimate. Uneven spatial coverage, with fewer measurements where mass balances are less negative, accounts for about 50 mm a−1 of underestimate. This figure derives from spatial interpolation based on global data on ice extent and on an analysis of correlations between balance time series. The correlogram shows exponential decay, the scale length being about 600 km. The largest bias is due to a newly detected dependence of mass balance on glacier size. Among the 231 measured glaciers, many are small and belong to a restricted size range in which balance is negative, but much of the small-glacier extent is accounted for by larger glaciers in a size range where balance is indistinguishable from zero. Correcting for this size bias increases the average balance to –35 ± 89 mm a−1. Inspection of time series for 1940–95 (251 glaciers) shows that mass balance was least negative during the 1960s, and has varied in broad agreement with Northern Hemisphere temperature anomalies; smaller small glaciers (A < 16 km2) appear to be more sensitive than larger small glaciers to changes in thermal forcing. The small-glacier contribution to sea-level rise implied by this assessment is only 0.06–0.32 mm a−1, consistent with glaciers in general making little or no contribution to sea-level change during 1961–90.