bluuebunny/crossref_metadata_2025_split huggingface dataset:
Climatic implications of reconstructed early–mid Pliocene equilibrium-line altitudes in the McMurdo Dry Valleys, Antarctica
Authors: Krusic A.G. , Prentice M.L. , Licciardi J.M. 
Published: March 2009

AbstractEarly–mid Pliocene moraines in the McMurdo Dry Valleys, Antarctica, are more extensive than the present alpine glaciers in this region, indicating substantial climatic differences between the early–mid Pliocene and the present. To quantify this difference in the glacier–climate regime, we estimated the equilibrium-line altitude (ELA) change since the early–mid Pliocene by calculating the modern ELA and reconstructing the ELAs of four alpine glaciers in Wright and Taylor Valleys at their early–mid Pliocene maxima. The area–altitude balance ratio method was used on modern and reconstructed early–mid Pliocene hypsometry. In Wright and Victoria Valleys, mass-balance data identify present-day ELAs of 800–1600ma.s.l. and an average balance ratio of 1.1. The estimated ELAs of the much larger early–mid Pliocene glaciers in Wright and Taylor Valleys range from 600 to 950±170ma.s.l., and thus are 250–600±170m lower than modern ELAs in these valleys. The depressed ELAs during the early–mid-Pliocene most likely indicate a wetter and therefore warmer climate in the Dry Valleys during this period than previous studies have recognized.
Comparison of mass balances for Vernagtferner, Oetzal Alps, as obtained from direct measurements and distributed modeling
Authors: Paul Frank , Escher-Vetter Heidi , Machguth Horst 
Published: March 2009

AbstractThe direct comparison of modeled glacier mass-balance distribution with field measurements could be problematic, as the methodology of determination and the processes considered at the point or catchment scale could differ strongly. Moreover, direct measurements cover only small parts of a glacier, and model performance is thus difficult to assess outside these regions. Remaining opportunities for model validation include comparison of snowlines, as derived from remote-sensing data, and maps of the mass-balance distribution, as interpreted by observers with local knowledge. This study compares such hand-drawn maps of the Vernagtferner (Oetzal Alps) mass balance with the modeled pattern as obtained from a distributed energy-/mass-balance model of intermediate complexity. The model is driven by measured daily values of temperature, global radiation and precipitation from a nearby climate station and grids of mean daily potential global radiation and climatologic annual precipitation sums. Compared with the direct measurements, the calculated mean mass balance and equilibrium-line altitude agreed very well in both balance years, although the spatial pattern of the mass-balance distribution displayed larger deviations in regions influenced by snowdrift or local topographic undulations. However, compared with the remaining snow as visible on a satellite image from 1999, the modeled snowline pattern for a larger sample of glaciers is in very good agreement.
Reconstruction of the annual balance of Vadret da Morteratsch, Switzerland, since 1865
Authors: Nemec Johanna , Huybrechts Philippe , Rybak Oleg , Oerlemans Johannes 
Published: March 2009

AbstractWe have reconstructed the annual balance of Vadret da Morteratsch, Engadine, Switzerland, with a two-dimensional energy-balance model for the period 1865–2005. The model takes into account a parameterization of the surface energy fluxes, an albedo that decreases exponentially with snow depth as well as the shading effect of the surrounding mountains. The model was first calibrated with a 5 year record of annual balance measurements made at 20 different sites on the glacier between 2001 and 2006 using meteorological data from surrounding weather stations as input. To force the model for the period starting in 1865, we employed monthly temperature and precipitation records from nearby valley stations. The model reproduces the observed annual balance reasonably well, except for the lower part during the warmest years. Most crucial to the results is the altitudinal precipitation gradient, but this factor is hard to quantify from the limited precipitation data at high elevations. The simulation shows an almost continuous mass loss since 1865, with short interruptions around 1920, 1935 and 1980. A trend towards a more negative annual balance can be observed since the beginning of the 1980s. The simulated cumulative mass balance for the entire period 1865–2005 was found to be –46mw.e.
20th-century climate change inferred from four long-term point observations of seasonal mass balance
Authors: Huss Matthias , Bauder Andreas 
Published: March 2009

AbstractFour long-term time series of seasonal mass-balance observations, all starting in 1914, have been compiled for two stakes on Claridenfirn and one stake on Grosser Aletschgletscher and Silvrettagletscher, Switzerland. These data represent the longest records of mass balance worldwide. A mass-balance model based on the temperature-index approach is used to correct field data for varying observation dates and data gaps and to separate accumulation and ablation. The homogenized continuous 93 year time series cover most of the 20th century and enable us to investigate temporal, regional and altitudinal variability in mass balance and changes in the climatic forcing on glaciers. A high-altitude site shows summer balance trends opposite to those at three stakes located near the equilibrium line. Since 1975, melt rates have increased by 10%(10 a)−1 periods of enhanced climatic forcing are detected: 1943–53 and 1987–2007. The energy consumed for melt was higher in the 1940s despite lower air temperatures compared to the years since 1987. We find evidence for a change in the glacier surface heat budget, which has important implications for the long-term stability of degree-day factors in empirical temperature-index modelling.
Sensitivity of net mass-balance estimates to near-surface temperature lapse rates when employing the degree-day method to estimate glacier melt
Authors: Gardner Alex S. , Sharp Martin 
Published: March 2009

AbstractGlacier mass-balance models that employ the degree-day method of melt modeling are most commonly driven by surface air temperatures that have been downscaled over the area of interest, using digital elevation models and assuming a constant free air lapse rate that is often taken to be the moist adiabatic lapse rate (MALR: –6.5°Ckm–1). Air-temperature lapse rates measured over melting glacier surface are, however, consistently less steep than free air values and have been shown to vary systematically with lower-tropospheric temperatures. In this study, the implications of including a variable near-surface lapse rate in a 26 year (1980–2006) degree-day model simulation of the surface mass balance of Devon Ice Cap, Nunavut, Canada, are examined and compared with estimates derived from surface air temperatures downscaled using a constant near-surface lapse rate equal to the measured summer mean (–4.9°Ckm–1) and the MALR. Our results show that degree-day models are highly sensitive to the choice of lapse rate. When compared with 23 years of surface mass-balance measurements from the northwest sector of the ice cap, model estimates are significantly better when surface air temperatures are downscaled using a modeled daily lapse rate rather than a constant lapse equal to either the summer mean or the MALR.
Four decades of winter mass balance of Vernagtferner and Hintereisferner, Austria: methodology and results
Authors: Escher-Vetter Heidi , Kuhn Michael , Weber Markus 
Published: March 2009

AbstractIn this study, long-term series of winter mass balances from two neighbouring glaciers in the southern Oetztal Alps, Austria, i.e. Hintereisferner and Vernagtferner, are analyzed with respect to the methods used in their determination. For this purpose, (1) some basic data of field surveys are presented, (2) the influence of different temporal systems is discussed, and (3) the profile, contour and a ‘model’ method based on energy-balance ablation modelling and measured net mass balance are discussed with respect to the reliability of the resulting series. The main findings of the investigations are: (1) The winter mass-balance series for Hintereisferner and Vernagtferner as determined with all applied methods result in a reliable climatologic average of 1000±100mmw.e. (2) When using the profile method, different spatial integration approaches are quite sensitive to the altitudinal coverage and the spatial pattern of observations. (3) The error of the model method occurs randomly, whereas contour as well as profile-method errors are more systematic. (4) Filtered time series from the two glaciers show similar tendencies for the last three decades.
The ‘benchmark glacier’ concept – does it work? Lessons from the North Cascade Range, USA
Authors: Fountain Andrew G. , Hoffman Matthew J. , Granshaw Frank , Riedel Jon 
Published: March 2009

AbstractBenchmark glaciers were established in many alpine areas during the 1960s as part of the International Hydrological Decade to represent ‘typical’ mass and energy processes on glaciers in different climatic regions around the world. These glaciers have received new interest in the past decade because they are used to infer the contribution of alpine glacier wastage to global sea-level rise. We compare South Cascade Glacier, the benchmark glacier for the northwest contiguous USA, and four other secondary glaciers, against the topographic, area and mass changes of 321 glaciers in the surrounding region. Results show that South Cascade Glacier is unusually large, of lower slope and much larger area and had mass losses greater than most other glaciers in the region. Three of the four secondary glaciers were much more typical. Year-to-year variations in mass balance were highly correlated between all five glaciers, and any of these glaciers, including the benchmark glacier, could be used to infer temporal mass variations in the region. However, the use of South Cascade Glacier to estimate area/mass losses for the region would result in overestimating the area/mass changes by a factor of three. Local differences in the magnitude of annual glacier mass balance control cumulative mass changes and area changes. There appears to be no way to select a representative glacier a priori, and knowledge of changes over the region is required. Therefore, there may be great uncertainty in estimates of sea-level rise from the wastage of alpine glaciers based on the benchmark approach. We recommend re-evaluation of regional glacier mass changes inferred from benchmark glaciers in critical regions.
Calculation of sensible-heat flux over a melting ice surface using simple climate data and daily measurements of ablation
Authors: Braithwaite Roger J. 
Published: March 2009

AbstractSensible-heat flux is obviously important for glacier ablation but is difficult to measure routinely. Sensible-heat flux can be estimated from wind-speed and temperature data using a dimensionless heat-transfer coefficient. Values of the heat-transfer coefficient are evaluated for six sites by correlating measured melt energy with a wind–temperature variable (product of daily mean wind speed, temperature and mean atmospheric pressure for the altitude in question). Data are available for short periods from two sites in Arctic Canada and two sites in North Greenland, and for hundreds of days of record at Nordbogletscher and Qamanârssûp sermia in South and West Greenland, respectively. Average transfer coefficients for four out of the six sites are close to 0.003, which is in reasonable agreement with values reported elsewhere, while larger values of 0.0047 and 0.0057 are found at the other two sites. Heat-transfer coefficients are also estimated on a monthly basis for the two long records, and substantial variations are found, suggesting that the method should not be used for <20–30 days of data. The present study is based on manually observed ablation and climate data, but the approach could be updated to use data from automatic recording stations using modern sensors.
Geodetic and direct mass-balance measurements: comparison and joint analysis
Authors: Graham Cogley J. 
Published: March 2009

AbstractThis paper describes a new compilation of both direct and geodetic mass-balance measurements, develops a procedure to reduce diverse balance measurements over different time-spans to common time-spans, and presents updated estimates of global average balance of small glaciers based on the enlarged compilation. Although geodetic measurements are fewer than direct measurements, they cover four times as many balance years. Direct and geodetic measurements are unbiased with respect to one another, but differences are often substantial. The statistical procedure can be understood by imagining that an n-year balance measurement is an average of a series of 1 year measurements. The series is hypothetical but we can calculate the uncertainty of each of its elements if, in addition to its measured average, we can also estimate its standard deviation. For this claim to be valid, the annual series must be stationary and normally distributed with independent (roughly, uncorrelated) elements, for which there is reasonable evidence. The need to know the standard deviation means that annual direct measurements from a nearby glacier, or equally reliable information about variability, are indispensable. Given this information, the new methodology results in moderately more negative balances. This is probably because tidewater glaciers are better represented in the geodetic data. In any case, the most recent published estimate of global average balance, 0.8–1.0mma–1 of sea-level equivalent for 2001–04, is now increased substantially to 1.1–1.4 mma–1 for 2001–05.
South Cascade Glacier mass balance, 1935–2006
Authors: Rasmussen L.A. 
Published: March 2009

AbstractA simple model uses daily observations of precipitation and temperature at a nearby weather station to estimate glacier-average seasonal mass-balance components at South Cascade Glacier, Washington, USA, from 1935, 24 years before measurements began at the glacier. This is 13 years earlier than measurements that can be derived using the NCEP–NCAR reanalysis database (begins 1 January 1948). Although the model’s error in estimating winter balance and summer balance over 1959–2006 is greater than that of a model using the reanalysis database, its error in estimating net balance is comparable. The model uses an empirically determined precipitation ratio between the station and the glacier, and a seasonally varying temperature lapse rate determined from 9 years of measurements at the glacier. Temperature is used with a degree-day formulation to estimate ablation and to partition precipitation between rain and snow for estimating accumulation. Both processes are assumed to exist throughout the year, and model results are compared seasonally with adjusted observations of winter and summer balances. The published mass-balance series is adjusted to a constant-topography (1970) series in an attempt to remove the influence of changing topography on the glacier’s response to climate. The reconstructed values prior to 1959 are also with respect to the 1970 glacier topography. Because precipitation is measured at the weather station, rather than being inferred from other meteorological variables, it enables us to distinguish more accurately between wet-day and dry-day conditions, including vertical lapse rates of temperature.
<i>In vitro</i> Regeneration of <i>Aristolochia tagala</i> Champ. A Rare Medicinal Plant of Chittagong Hill Tracts
Authors: Biswas Animesh , Bari MA , Roy Mohashweta , Bhadra SK 
Published: March 2009

An efficient regeneration protocol through in vitro direct organogenesis was developed for a valuable medicinal plant Aristolochia tagala Champ. using nodal segments as explants. Multiple shoot buds were induced directly from nodal explants cultured on MS (Murashige and Skoog 1962) basal medium supplemented with 2.0 mg/l BAP (N6- benzylaminopurine) and 0.5 mg/l NAA (a-naphthalenacetic acid). The average number of shoots induced per culture was found to be six. Excised shoot roots were cultured on half-strength MS medium containing 0.5 mg/l IBA. The rooted plantlets were transferred to natural environment after proper acclimatization. Â Key words: Aristolochia tagala, rare medicinal plant, direct organogenesis. doi: 10.3329/jbs.v15i0.2204 J. bio-sci. 15: 63-67, 2007 Â Â Â Â
Influence of Irrigation, Fertilizer and Variety on Grain Growth of Barley (<i>Hordeum vulgare</i> L.)
Authors: Mollah MSI , Paul NK 
Published: March 2009

An experiment was conducted in the experimental field of Rajshahi University Campus (AEZ-11) to study the influence of soil moisture and NPK fertilizers on grain growth of four varieties of barley (Hordeum velgare L.). Spikelet number (SN), spike dry weight (SDW), grain number (GN), grain dry weight (GDW), spike relative growth rate (spike RGR) and grain relative growth rate (grain RGR) were observed highest in the highest level of irrigation (40 mm). The highest amount of fertilizer (120N 75P 45K) produced the highest SN, SDW, GN, GDW, spike RGR and grain RGR. BHL-3 produced the highest SN, BARI Barley -2 produced the highest spike RGR, BARI Barley -1 produced the highest grain RGR and BL-1 produced the highest SDW, GN, and GDW. Key words: Irrigation, soil moisture, fertilizers, barley, grain growth. Â doi: 10.3329/jbs.v15i0.2205 J. bio-sci. 15: 69-75, 2007
Dosimetry of cell-monolayers in multiwell plat
Authors: Andreeff M. , Oehme L. , Kotzerke J. , Freudenberg R. 
Published: March 2009

Summary
Aim: Irradiation of cells in-vitro with unsealed radionuclides is often carried out in cylindrical multi-well-plates. For calculation of the absorbed dose using the sphere model is common. This model assumes a spherical distribution of activity. However, by physical aspects a dose reduction in the peripheral area of the activity volume is expected and predicted especially for high-energy beta-emitting radionuclides. The impact on cellular dosimetry shall be depicted in this paper. Methods: The dose-distribution inside a multi-well-plate was calculated by convolving the dose distribution around a point source with a given activity. This was performed for the radionuclides I-131, Re-188 and Y-90 in wells of different sizes. For comparison the sphere dose was also calculated. Results: Depending on the beta-energy differences up to 40% between the mean calculated dose and the mean sphere dose were found, whereby calculated dose was always lower than the sphere model prediction. Furthermore a fall-off was calculated for the bottom-dose compared to dose in the centre. An analytical expression was revealed for the bottom-dose with respect to the filling level for three different wells. Conclusion: The shape of geometry and the influence on dose distribution must be considered especially at in-vitro exposure with low energy and short range beta-emitting radionuclides. There could be a great impact for exact dose estimation, which is especially necessary to know for comparison of different irradiation experiments (e.g. different radionuclides, various irradiation geometries or comparison with x-rays).
Subjective perception of radioactivity
Authors: Müller S. P. , Beyer T. , Bockisch A. , Freudenberg L. S. 
Published: March 2009

Summary
Aim: We assess the attitude of patients with thyroid disease towards radiation and radioactivity before and after radioiodine therapy by means of a cultural-anthropological approach. We evaluate in patient interviews how their subjective attitude towards radioactivity as an abstract term and towards radioactivity in the medical context on the basis of their personal experiences with radionuclide therapy. Patients, methods: 29 patients with autonomously functioning thyroid lesions (17 women, 12 men, 35–79 years) were included in this study. All patients were interviewed prior to and 22–27 month post radioiodine therapy in an open dialogue with the principal investigator. Patients were asked to describe their attitude towards radioactivity in general and towards radioiodine therapy in particular. Patients were asked to use a scoring system (1: positive, 5: negative) to quantify their perception of radioactivity. Results: The personal perception of radio - activuty as an abstract term does not change significantly (p = 0.15) before and after radioiodine therapy. This perception is linked to mostly negative impressions of radiactivity. However, patients become more positive when assessing the value of radioactivity as part of their therapy regimen. Thus, we observe a significant increase in percepted value of radioactivity post radioiodine therapy (p = 0.03). Conclusion: Patients continue to view radioactivity as something negative despite treatment success following radioiodine therapy. Our results provide useful information for patient information by the nuclear medicine physician prior to a radioiodine therapy.
Grossly apparent cartilage erosion of the patellar articular surface in dogs with congenital medial patellar luxation
Authors: Janssens L.A. , Béosier Y.M. , Daems R. 
Published: March 2009

SummaryOne hundred and forty-five stifles of client-owned dogs that underwent corrective surgery for congenital medial patellar luxation were inspected for cartilage erosion on the articular surface of the patella. The lesions were mapped in surface percentage ranges of 20% and by location. Two-thirds of the patellae had cartilage erosion. Cartilage erosion varied between 0 and 100% of the total patellar articular surface and was localised mainly on the medial and distal side of the patella. Dogs with Grade IV patellar luxations and heavier dogs were more affected. The majority of dogs in our study with congenital medial patellar luxation had grossly apparent cartilage erosion on the articular surface of the patella, which may help to explain why certain patients do not function well clinically after technically successful corrective surgery.
The role of computed tomography in the classification and management of pelvic fractures
Authors: Clements D. , Farrell M. , Heller J. , Bennett D. , Carmichael S. , Draffan D. 
Published: March 2009

SummaryComputed tomography (CT) imaging is an important component in the pre-operative assessment of pelvic fractures in humans. The value of CT images in the management of small animal pelvic fractures is presently undetermined. The objective of this study was to investigate the benefits of CT images on the management of pelvic fractures. A prospective study of 25 traumatised cases of canine and feline pelvic fractures were evaluated, where CT images and conventional orthogonal radiographic assessments were performed on each case. Three diplomat orthopaedic surgeons independently reviewed the radio-graphs and CT images on separate occasions and determined fracture classification, management plan, estimated recovery time and prognosis. A consensus review of the imaging modalities and surgical reports was used as the definitive fracture description. For all observers, management was not found to differ significantly between radiographic and CT analysis (P< 0.05). There was moderate agreement between observers and between imaging modalities for fracture description. Greatest discrepancy was found as the fracture complexity increased, such as with acetabula and sacral fractures, whereby CT was the most sensitive. Clinically high quality radiography would be recommended for all pelvic fracture cases; CT may be beneficial where there is uncertainty, particularly with acetabula fractures or sacral fractures causing neurological deficits. Experienced orthopaedic surgeons often disagreed on the diagnosis, treatment and prognosis of pelvic trauma.