bluuebunny/crossref_metadata_2025_split huggingface dataset:
Bed properties and hydrological conditions underneath McCall Glacier, Alaska, USA
Authors: Pattyn Frank , Delcourt Charlotte , Samyn Denis , de Smedt Bert , Nolan Matt 
Published: August 2009

AbstractDuring three summer field seasons (2003, 2005 and 2006) we carried out radio-echo sounding measurements with a 5MHz (central frequency) ice-penetrating radar on McCall Glacier, Arctic Alaska, USA, along the central flowline and 17 cross-profiles. Two-way travel time was, after migration, converted to ice thickness, which, in combination with a recent digital elevation model of the surface of the glaciated area, resulted in a detailed map of the bed topography. This reveals a complex basal topography in the confluence area of the different glacial cirques. The pattern of subglacial water flow following the hydraulic potential gradient was calculated for the whole glacier area and shows a confluence of subglacial water downstream from the confluence of the glacier cirques. From the ice-thickness map the total ice volume was estimated as slightly less than 0.5 km3. Bed reflection power (BRP) was determined for the glacier after correction for ice-thickness dependence. Results reveal a clear relationship between the BRP pattern and basal sliding anomalies along the central flowline.
Structural controls on englacial esker sedimentation: Skeiðarárjökull, Iceland
Authors: Burke Matthew J. , Woodward John , Russell Andrew J. , Jay Fleisher P. 
Published: August 2009

AbstractWe have used ground-penetrating radar (GPR) to observe englacial structural control upon the development of an esker formed during a high-magnitude outburst flood (jökulhlaup). The surge-type Skeiðarárjökull, an outlet glacier of the Vatnajökull ice cap, Iceland, is a frequent source of jökulhlaups. The rising-stage waters of the November 1996 jökulhlaup travelled through a dense network of interconnected fractures that perforated the margin of the glacier. Subsequent discharge focused upon a small number of conduit outlets. Recent ice-marginal retreat has exposed a large englacial esker associated with one of these outlets. We investigated structural controls on esker genesis in April 2006, by collecting >2.5km of GPR profiles on the glacier surface up-glacier of where the esker ridge has been exposed by meltout. In lines closest to the exposed esker ridge, we interpret areas of englacial horizons up to ~30m wide and ~10–15m high as an up-glacier continuation of the esker sediments. High-amplitude, dipping horizons define the base of esker materials across many lines. Similar dipping surfaces deeper in the profiles suggest that: (1) the dipping surfaces beneath the esker are englacial tephera bands; (2) floodwaters were initially discharged along structurally controlled englacial surfaces (tephra bands); (3) the rapid increase in discharge resulted in hydrofracturing; (4) establishment of preferential flow paths resulted in conduit development along the tephra bands due to localized excavation of surrounding glacier ice; and (5) sedimentation took place within the new accommodation space to form the englacial structure melting out to produce the esker.
A new regional high-resolution map of basal and surface topography for the Greenland ice-sheet margin at Paakitsoq, West Greenland
Authors: Mottram Ruth , Nielsen Claus , Ahlstrøm Andreas P. , René Niels , Kristensen Steen S. , Christensen Erik L. , Forsberg Rene´ , Stenseng Lars 
Published: August 2009

AbstractIn 2005 an airborne survey was carried out from a Twin Otter aircraft at Pâkitsup Akuliarusersua (Paakitsoq) near Ilulissat in West Greenland. The survey aimed to measure ice thickness with a 60 MHz coherent radar and surface elevation with a scanning laser altimeter. Positioning information came from multiple on-board differential GPS units and an inertial navigation system. The region surveyed covers >80km along the ice margin and has a total area of ~2700km2 with varying density of measurements: the between-track distance was ~1 km near the margin, increasing to ~3km away from the margin. Regional high-resolution maps of basal topography under the Greenland ice sheet are useful for resolving important glaciological and hydrological questions and for enhancing related process studies, such as the influence of basal meltwater on ice dynamics. The ice-sheet margin in this region is also currently under consideration for hydropower development and has a long and continuing history of glaciological investigations, lately with emphasis on the connection between surface meltwater formation and surface velocity of the ice sheet. Here we present a new regional map of the surface and basal topography of the ice-sheet margin and discuss some of the implications for reported observations at Swiss Camp.
Flow dynamics of the Rutford Ice Stream ice-drainage basin, West Antarctica, from radar stratigraphy
Authors: King E.C. 
Published: August 2009

AbstractRutford Ice Stream, West Antarctica, drains a catchment of >45 000 km2into the Ronne Ice Shelf through a 26 km wide, 2.4 km deep subglacial trough adjacent to the Ellsworth Mountains. Forty-two per cent of its catchment boundary is common with Pine Island Glacier, where rapid change to ice dynamics is currently underway. These changes may eventually affect adjacent catchments such as Rutford. Radar sounding data were acquired over the Rutford ice-drainage basin that show the internal structure. In particular, distinctive reflector groups were identified that mark the boundaries between four different flow elements. The flow-margin reflector groups include curvilinear events that cross-cut isochrones and are therefore likely to be post-depositional. These reflections may arise from crystal orientation fabrics generated by localized strain in a flow margin. One of the sectors of the ice-drainage basin supplies the largest share (38%) of the ice volume flux through the main trunk of Rutford Ice Stream. This sector may be preferentially affected by continuing surface lowering in the Pine Island Glacier catchment.
Radar signatures beneath a surface topographic lineation near the outlet of Kamb Ice Stream and Engelhardt Ice Ridge, West Antarctica
Authors: Matsuoka Kenichi , Gades Anthony , Conway Howard , Catania Ginny , Raymond Charles F. 
Published: August 2009

AbstractVisible and infrared satellite images reveal numerous lineations on the Siple Coast region of West Antarctica. We used 5 MHz ice-penetrating radar to probe the interior and the bed of the ice sheet beneath a lineation at the boundary between Engelhardt Ice Ridge and flat-ice terrain to the south of the Kamb Ice Stream (KIS) outlet. Results show curved reflectors that emerge from the bed beneath 600 m thick ice. The tops of the reflectors extend about 100m into the ice above the bed, where they become almost horizontal. Apparent reflectivity of the horizontal section is about 20 dB less than that of the bed. We conclude that the likely cause of such strong reflection is sea water that was accreted into basal crevasses when the flat-ice terrain was floating. Internal layers are warped downward just downslope from the basal reflectors. It is thought that the downwarping was caused by localized basal melting in the past. The spatial pattern of downwarping suggests that localized basal melting was stronger on the north side than on the south side of KIS; apparently ice/ocean interactions on the two sides of KIS were different.
Radioglaciological studies on Hurd Peninsula glaciers, Livingston Island, Antarctica
Authors: Navarro F.J. , Otero J. , Macheret Yu.Ya. , Vasilenko E.V. , Lapazaran J.J. , Ahlstrøm A.P. , Machío F. 
Published: August 2009

AbstractWe present the results of several radio-echo sounding surveys carried out on Johnsons and Hurd Glaciers, Livingston Island, Antarctica, between the 1999/2000 and 2004/05 austral summer campaigns, which included both radar profiling and common-midpoint measurements with low (20– 25 MHz)- and high (200 MHz)-frequency radars. The latter have allowed us to estimate the radio-wave velocity in ice and firn and the corresponding water contents in temperate ice, which vary between 0 and 1.6% depending on the zone. Maximum ice thickness is ~200 m, with a mean value of 93.6±2.5 m. Total ice volume is 0.968±0.026 km3, for an area of 10.34±0.03km2. The subglacial relief of Johnsons Glacier is quite smooth, while that of Hurd Glacier shows numerous overdeepenings and peaks. The radar records suggest that Hurd Glacier has a polythermal structure, contrary to the usual assumption that glaciers in Livingston Island are temperate. This is also supported by other dynamical and geomorphological evidence.
Deducing the thermal structure in the tongue of Gornergletscher, Switzerland, from radar surveys and borehole measurements
Authors: Eisen O. , Bauder A. , Lüthi M. , Riesen P. , Funk M. 
Published: August 2009

AbstractWe present the thermal distribution in the confluence area of Gorner- and Grenzgletscher, Valais, Switzerland. The area was mapped by ice-penetrating radar at 1–5 and 40 MHz. The higher-frequency data reveal a thick surface layer of low backscatter in the center of the Grenzgletscher branch. Based on datasets of borehole-temperature measurements and flow velocity, we interpret this as a thick layer of cold ice, advected from the accumulation region of Grenzgletscher. Along seven profiles the base of the low-backscatter zone can be found at a maximum depths between approximately 100 and 200 m. Laterally, the layer extends some 400 m, ∼1/3 of the width of the Grenzgletscher branch. The lower boundary of the low-backscatter zone is systematically higher than the cold–temperate transition surface found in the boreholes. This discrepancy is attributed to the direct sensitivity of radar backscatter to liquid-water inclusions, rather than to the temperature distributions as observed in boreholes. We present the current state of the cold layer and discuss its influence on other glacier characteristics.
Automated Identification of Diagnosis and Co-morbidity in Clinical Records
Authors: Cano C. , Blanco A. , Peshkin L. 
Published: August 2009

Summary
Objectives: Automated understanding of clinical records is a challenging task involving various legal and technical difficulties. Clinical free text is inherently redundant, unstructured, and full of acronyms, abbreviations and domain-specific language which make it challenging to mine automatically. There is much effort in the field focused on creating specialized ontology, lexicons and heuristics based on expert knowledge of the domain. However, ad-hoc solutions poorly generalize across diseases or diagnoses. This paper presents a successful approach for a rapid prototyping of a diagnosis classifier based on a popular computational linguistics platform.
Methods: The corpus consists of several hundred of full length discharge summaries provided by Partners Healthcare. The goal is to identify a diagnosis and assign co-morbidity. Our approach is based on the rapid implementation of a logistic regression classifier using an existing toolkit: LingPipe (http://alias-i.com/lingpipe). We implement and compare three different classifiers. The baseline approach uses character 5-grams as features. The second approach uses a bag-of-words representation enriched with a small additional set of features. The third approach reduces a feature set to the most informative features according to the information content.
Results: The proposed systems achieve high performance (average F-micro 0.92) for the task. We discuss the relative merit of the three classifiers. Supplementary material with detailed results is available at: http://decsai.ugr.es/~ccano/LR/supplementary_material/

Conclusions: We show that our methodology for rapid prototyping of a domain-unaware system is effective for building an accurate classifier for clinical records.
Applicability of Lewin´s Change Management Model in a Hospital Setting
Authors: Prokosch H.-U. , Ganslandt T. , Šuc J. 
Published: August 2009

Summary
Objectives: Today’s socio-economic developments in the healthcare area require continued optimization of processes and cost structures at hospitals, often associated with process changes for different occupational groups in the hospital. Formal methods for managing change have been established in other industries. The goal of this study was to assess the applicability of Kurt Lewin’s change management method to a health informatics-related project at a German university hospital.
Methods: A project at the University Hospital Erlangen introducing changed requirements in the documentation of costly material in the surgical area was conducted following the concept of Lewin’s approach based on field theory, group dynamics, action research and the three steps of change. A data warehouse contributed information to several steps in the change process.
Results: The model was successfully applied to the change project. Socio-dynamic forces relevant to the project goals were identified and considered in the design of the new documentation concept. The achieved documentation level met the new requirements and in some areas even exceeded them.
Conclusions: Based on the project experiences, we consider Kurt Lewin’s approach applicable to change management projects in the hospital sector without a requirement for substantial additional resources, however, specific hospital characteristics need to be taken into account. The data warehouse played an important role by providing essential contributions throughout the entire change process.
Automatic Brain Segmentation in Time-of-Flight MRA Images
Authors: Säring D. , Fiehler J. , Illies T. , Möller D. , Handels H. , Forkert N. D. 
Published: August 2009

Summary
Objectives: Cerebral vascular malformations might, caused by ruptures, lead to strokes. The rupture risk depends to a great extent on the individual anatomy of the vasculature. The 3D Time-of-Flight (TOF) MRA technique is one of the most commonly used non-invasive imaging techniques to obtain knowledge about the individual vascular anatomy. Unfortunately TOF images exhibit drawbacks for segmentation and direct volume visualization of the vasculature. To overcome these drawbacks an initial segmentation of the brain tissue is required.
Methods: After preprocessing of the data is applied the low-intensity tissues surrounding the brain are segmented using region growing. In a following step this segmentation is used to extract supporting points at the border of the brain for a graph-based contour extraction. Finally a consistency check is performed to identify local outliers which are corrected using non-linear registration.
Results: A quantitative validation of the method proposed was performed on 18 clinical datasets based on manual segmentations. A mean Dice coefficient of 0.989 was achieved while in average 99.56% of all vessel voxels were included by the brain segmentation. A comparison to the results yielded by three commonly used tools for brain segmentation revealed that the method described achieves better results, using TOF images as input, which are within the inter-observer variability.
Conclusion: The method suggested allows a robust and automatic segmentation of brain tissue in TOF images. It is especially helpful to improve the automatic segmentation or direct volume rendering of the cerebral vascular system.
Physical Activity and Postmenopausal Breast Cancer
Authors: Schmidt M. E. , Chang-Claude J. , Slanger T. , Obi N. , Flesch-Janys D. , Steindorf K. 
Published: August 2009

Summary
Objectives: Epidemiological evidence suggests an inverse association between physical activity (PA) and postmenopausal breast cancer risk. Breast cancer is a heterogeneous disease, influenced by reproductive factors, lifestyle pattern, and predispositions. We investigated whether these risk factors modify the effect of PA on breast cancer risk.
Methods: We analyzed data from 2004 hormone-receptor-positive postmenopausal breast cancer cases and 6569 controls from the population-based MARIE study conducted 2002–2005 in Germany. Interaction was statistically tested using adjusted unconditional logistic regression models.
Results: The inverse association between leisure-time PA and risk of postmenopausal hormone-receptor-positive breast cancer was not heterogeneous by family history of breast cancer or by hormone therapy. PA showed a significant interaction with benign breast diseases (p = 0.023) and with breastfeeding (p = 0.045) but not with parity (p = 0.94), with clear risk reductions only for women who ever had breastfed or who ever had a benign breast disease (among ever breastfed: odds ratio = 0.63; 95% confidence interval = (0.52, 0.77), highest vs. lowest PA quartile). Interaction with BMI was weak (p = 0.053).
Conclusions: Breastfeeding and benign breast diseases modified the effect of PA on postmenopausal breast cancer risk. If other studies find similar modifications, increasing knowledge about these risk factors may contribute to a better understanding of the mode of action of PA on breast cancer risk. For women who are at higher risk for breast cancer due to family history or due to hormone therapy use, it is encouraging that they might lower their risk by being physically active.
A Case Study on Physiology-Based Drought Screening of Coconut with Selected Accessions
Authors: Nainanayake AD , Morison JIL 
Published: August 2009

Recurrent droughts in Sri Lanka, now becoming increasingly frequent, cause substantial losses in coconut production. Consequently, the development of drought tolerant coconut varieties is an urgent need. Yield is the most reliable parameter to evaluate genotypes for drought tolerance but yield-based evaluation is a complex and time consuming exercise with a perennial tree crop like coconut. With the objective of identifying drought tolerant varieties, 40 coconut forms or accessions (forms/acc) in the germplasm collection at Coconut Research Institute of Sri Lanka (CRISL) have been screened. This ongoing investigation gathered information on different types of parameters, and data on a wide range of physiological parameters of adult coconut palms, during an 81-day natural drought was available, along with soil moisture readings in the manure circle. Five contrasting forms/acc (Clovis, Kasagala, Dwarf Green, Cameroon Red Dwarf, and Dwarf x Tall hybrid DT), out of the forty screened, were selected for the present case study to explore the behaviour of some important physiological functions during a drought, their relationships, and the possibility of developing a method for rapid selection of putative drought tolerant coconut palms, based on easily measurable physiological parameters. The response to drought, in terms of physiological parameters, varied in the forms/acc selected for the case study. Clovis was identified as a putative drought tolerant form/acc as it maintained a high rate of photosynthesis and water use efficiency even at the end of the dry spell. Cameroon Red Dwarf was the most drought sensitive. Kasagala showed a degree of drought tolerance, oriented towards survival, with conservation and efficient use of available soil water. However, Kasagala is not likely to be viable as a commercial crop as its low photosynthetic rate due to low stomatal conductance is indicative of low potential productivity. Drought sensitivity 1 of DT was at an intermediate level. The assimilation rate of DT was 20% higher than the mean rate of other forms/acc up to mild levels of water stress, but declined sharply when soil moisture content decreased below 15%. However, it recovers very quickly on rewetting of the soil with the onset of rains, which enables it to maintain a high overall yield. The drop in coconut production when soil water is deficient is mainly due to limitations at the stomatal level rather than at the non-stomatal (biochemical) level of the assimilation process, especially in mild to moderate drought conditions. Screening for drought tolerance based on physiological parameters appears to be rapid and promising. Nevertheless, these procedures should be further verified with long-term yield data of more forms/acc before they are widely applied. Key words: Coconut, drought tolerance, water use efficiency, photosynthesis, stomatal limitation doi: 10.4038/cocos.v18i0.985 COCOS (2007), 18
Available Soil Phosphorus in Coconut Plantations in Boralu and Pallama Soil Series, under different Fertilizer Regimes, in Gampaha District of Sri Lanka
Authors: Jayakody JADSS , Tennakoon NA , Fernandopulle MND 
Published: August 2009

Coconut plantations in the Gampaha District of Sri Lanka are generally under fertilized or not fertilized at all. The available soil phosphorus in the two major coconut growing soils in the district viz. Boralu and Pallama series, under three fertilizer regimes, organic manures, inorganic fertilizers, or no fertilizer, over the preceding five-year period, was determined and mapped. Some 32,400 ha were covered with 30 sampling locations. Leaf P content was also determined at selected sampling locations. Available P in the Boralu and Pallama soils was at a ‘medium' level of sufficiency, with a mean of 16 mg/kg, even in unfertilized coconut plantations. Leaf-P concentration in all the coconut plantations fertilized annually with inorganics, ranging from 0.135 to 0.196%, were higher than the critical leaf-P concentration (0.120%). These findings show that the available phosphorus in the two major soil series in the Gampaha District, were generally sufficient to support a healthy growth of coconut. Key Words: Available phosphorus, Boralu soil series, Coconut, Fertilizer, Pallama soil series. doi: 10.4038/cocos.v18i0.987COCOS (2007), 18
Effect of Abscisic Acid on Survival and Recovery of Cryopreserved Plumule Explants of Coconut (<i>Cocos nucifera</i>)
Authors: Bandupriya HDD , Fernando SC , Verdeil J-L , Malaurie B 
Published: August 2009

Cryopreservation has great potential for long-term storage of coconut genetic resources. The recent development of the encapsulation-dehydration cryogenic technique dramatically facilitated progress with cryopreservation. The present study tested the effect of abscisic acid in the encapsulationdehydration method for cryopreservation of coconut plumules. Plumules were excised from mature zygotic embryos of Coconut var. Sri Lanka Tall and encapsulated in calcium alginate. The alginate beads were used to test effect of different cryoprotection pretreatments (mixtures of 0.75 M sucrose and abscisic acid (ABA) at concentrations of 0, 10, 20 and 40 μM), and exposure to silica gel for 16 hours for further dehydration, prior to freezing in liquid nitrogen. Effect of the treatments without freezing was also tested. The water loss from alginate beads following sucrose incubation and dehydration was monitored, and the survival and growth of plumules assessed at different stages. Addition of ABA to the sucrose pretreatment medium increased the survival rate of unfrozen plumules from 60% to over 80%. Pretreatment with 40 μM ABA gave the highest survival rate (84%) of frozen plumules. The recovery rate of plumules (frozen and unfrozen) pretreated without ABA was very low (6-8%). The addition of ABA increased the recovery rate significantly; frozen plumules that had been treated with 40 μM ABA recorded a 39% recovery rate. The improved recovery could be ascribed to increased water loss (69%) in plumules treated with 40 μM ABA. Key words: Coconut, plumule, cryopreservation, abscisic acid doi: 10.4038/cocos.v18i0.989COCOS (2007), 18