Hysteretic evolution of ice rises and ice rumples with variations in sea level

Ice rises and ice rumples are locally grounded features found in coastal Antarctica and are surrounded by otherwise freely floating ice shelves. An ice rise has an independent flow regime, whereas the flow regime of an ice rumple conforms to that of the ice shelf and merely slows the flow of ice. In both cases, local highs in the bathymetry are in contact with the ice shelf from below, thereby regulating the large-scale ice flow, with implications for the upstream continental grounding line position. This buttressing effect, paired with the suitability of ice rises as a climate archive, necessitates a better understanding of the transition between ice rise and ice rumple, their evolution in response to a change in sea level, and their dynamic interaction with the surrounding ice shelf. We investigate this behaviour using a three-dimensional full Stokes ice flow model. The simulations span end-member basal friction scenarios of almost stagnant and fully sliding ice at the ice-bed interface. We analyse the coupling with the surrounding ice shelf by comparing the deviations between the non-local full Stokes surface velocities and the local shallow ice approximation (SIA). Deviations are generally high at the ice divides and small on the lee sides. On the stoss side, where ice rise and ice shelf have opposing flow directions, deviations can be significant. Differences are negligible in the absence of basal sliding where the corresponding steady state ice rise is larger and develops a fully independent flow regime that is well described by SIA. When sea level is increased and a transition from ice rise to ice rumple is approached, the divide migration is more abrupt the higher the basal friction. In each scenario, the transition occurs after the stoss side grounding line has moved over the bed high and is positioned on a retrograde slope. We identify a hysteretic response of ice rises and ice rumples to changes in sea level, with grounded area being larger in a sea level increase scenario than in a sea level decrease scenario. This hysteresis not only shows irreversibility following an equal increase and subsequent decrease in sea level, but also has important implications for ice flow model initialisation. The initial grounded area needs to be carefully considered, as this will determine the formation of either an ice rise or an ice rumple, thereby causing different buttressing effects

Ocena wyników leczenia wypadania narządów dna miednicy metodą zmodyfikowanej perineokolporektopeksji. Doświadczenia własne

Objectives: Anatomical and functional results of a modified sacral perineocolporectopexy for extreme forms of complex pelvic organs prolapse. Material and methods: Between 2005 and 2010, 10 women aged 47-75 years were treated by abdomino-perineal implantation of polypropylene mesh for modified sacral perineocolporectopexy and subsequently followed-up. They were suffering from enterocele (9 pts), genital prolapse (8 pts), descending perineum (5 pts), rectal prolapse (4 pts), rectocele (3 pts). Five women were incontinent (mean Wexner: 9) and six had incomplete rectal evacuation. Defecography revealed enterocele III°(5 pts) and II°(4 pts). MR designed descending perineum in 5 pts (mean: 3,8cm). Results: Permanent reconstruction of the pelvic floor and remission of organs prolapse was achieved at 12-months follow-up in all except 1 patient. There were 2 small vaginal erosions of the mesh and 1 haematoma within the pelvic floor. Improvement at rectal emptying was found in 4 patients, feeling of pelvic heaviness in 6 patients, dyspareunia in 3 patients. Mean incontinence score decreased from 9 to 4. Conclusions: 1. Modified sacral perineocolporectopexy is effective in the treatment of complex pelvic floor anatomical defects and organ prolapse. 2. Improvements in rectal emptying, pelvic feeling of heaviness and dyspareunia have been achieved. 3. The implant tolerance was good and the complications rate was law.Cel pracy: Ocena wyników leczenia wypadania narządów dna miednicy metodą zmodyfikowanej perineokolporektopeksji. Materiał i metody: W latach 2005–2010, 10 pacjentek w wieku od 45 do 75 lat zostało poddanych zabiegowi perineokolporektopeksji z implantacją siatki polipropylenowej z dostępu brzuszno-kroczowego. U 9 pacjentek występowało enterocele, u 8 wypadanie narządów rodnych, w 5 przypadkach obniżenie dna miednicy, w 4 przypadkach wypadanie odbytnicy, a w 3 rektocele. Pięć kobiet skarżyło się na nietrzymanie stolca (śr Wexner: 9) a 6 na brak pełnego opróżnienia odbytnicy. Defekografia wykazała obecność enterocele III° u 5 pacjentek i II° u kolejnych 4 rezonans magnetyczny uwidocznił obniżenie dna miednicy w 5 przypadkach (śr o 3,8cm). Wyniki: U 9 pacjentek w 12-mięsięcznej obserwacji osiągnięto trwałą rekonstrukcję dna miednicy i ustąpienie wypadania narządów. Odnotowano dwa przypadki erozji siatki przez pochwę oraz jeden krwiak w miednicy mniejszej. Poprawę opróżniania odbytnicy stwierdzono u 4 pacjentek, uczucia ciężkości w miednicy u 6, a dyspareunii u 3 kobiet. Średni współczynnik nietrzymania stolca obniżył się z 9 do 4. Wnioski: 1. Zmodyfikowana krzyżowa perineokolporektopeksja jest skutecznym leczeniem złożonych anatomicznie defektów dna miednicy oraz wypadania narządów. 2. Osiągnięto poprawę w zakresie opróżniania odbytnicy, uczucia ciężkości w miednicy i dyspareunii. 3. Zabieg cechował się dobrą tolerancją materiału protetycznego i niskim odsetkiem powikłań

Do We Know What We Need? Preference for Feedback About Accurate Performances Does Not Benefit Sensorimotor Learning

Previous research on skill acquisition has shown that learners seem to prefer receiving knowledge of results (KR) about those trials in which they have performed more accurately. In the present study, we assessed whether this preference leads to an advantage in terms of skill acquisition, transfer, and retention of their capacity to extrapolate the motion of decelerating objects during periods of visual occlusion. Instead of questionnaires, we adopted a more direct approach to investigate learners' preferences for KR. Participants performed 90 trials of a motion extrapolation task (acquisition phase) in which, every three trials, they could decide between receiving KR about their best or worst performance. Retention and transfer tests were carried out 24 hr after the acquisition phase, without KR, to examine the effects of the self-selected KR on sensorimotor learning. Consistent with the current literature, a preference for receiving KR about the most accurate performance was observed. However, participants' preferences were not consistent throughout the experiment as less than 10% (N = 40) selected the same type of KR in all their choices. Importantly, although preferred by most participants, KR about accurate performances had detrimental effects on skill acquisition, suggesting that learners may not always choose the KR that will maximize their learning experiences and skill retention

Telecommunications Regulatory Reform during the Carter Years: Origins, Conflicts and Impacts

Regulatory reform by the federal government advanced during the years of Jimmy Carter's presidency. This paper addresses positions taken by Carter's administration and by congress which focused on telecommunications policy issues. It explores how policies changed and the impacts which resulted

Assessment of adherence to visual correction and occlusion therapy in the Infant Aphakia Treatment Study

AbstractOcclusion therapy throughout early childhood is believed to be efficacious in treating deprivation amblyopia but has not been rigorously assessed in clinical trials. Further, tools to assess adherence to such therapy over an extended period of time are lacking. Using data from the Infant Aphakia Treatment Study, a randomized clinical trial of treatment for unilateral congenital cataract, we examined the use of quarterly 48-h recall interviews and annual 7-day prospective diaries to assess reported hours of patching in 114 children throughout the first 5 years of life. Consistency of data reported was assessed using correlation coefficients and intraclass correlation coefficients. Both interview and diary data showed excellent consistency with Cronbach’s Alpha’s ranging from 0.69 to 0.88 for hours of patching and 0.60 to 0.73 for hours of sleep. However, caregivers reported somewhat more adherence in prospective diaries than retrospective interviews. Completion rates, on the other hand, were substantially higher for telephone interviews than prospective diaries. For example, four years after surgery response rates to telephone interviews exceeded 75% versus completion rates of only 54% for diaries. In situations where occlusion dose monitors cannot be used for assessing adherence to occlusion therapy, such as in infants or over an extended period of time, quantitative assessments of occlusion therapy can be obtained by parental report, either as a series of prospective diaries or a series of recall interviews

Mass customization of teaching and learning in organizations

In search of methods that improve the efficiency of teaching and training in organizations, several authors point out that mass customization (MC) is a principle that covers individual needs of knowledge and skills and, at the same time, limits the development costs of customized training to those of mass training. MC is proven and established in the economic sector, and shows high potential for continuing education, too. The paper explores this potential and proposes a multidisciplinary, pragmatic approach to teaching and training in organizations. The first section of the paper formulates four design principles of MC deduced from an examination of economics literature. The second section presents amit™, a frame for mass customized training, designed according to the principles presented in the first section. The evaluation results encourage the further development and use of mass customized training in continuing education, and offer suggestions for future research

Evolution of Derwael Ice Rise in Dronning Maud Land, Antarctica, over the last millennia

Ice rises situated in the ice-shelf belt around Antarctica have a spatially confined flow regime with local ice divides. Beneath the divides, ice stratigraphy often develops arches with amplitudes that record the divide's horizontal residence time andsurface elevation changes. To investigate the evolution of Derwael Ice Rise, Dronning Maud Land, Antarctica, we combine radar and GPS data from three consecutive surveys, with a two-dimensional, full Stokes, thermomechanically-coupled, transient ice-flow model. We find that the surface mass balance (SMB) is higher on the upwind and lower on the downwind slopes. Near the crest, the SMB is anomalously low and causes arches to form in the shallow stratigraphy, observable by radar. In deeper ice, arches are consequently imprinted by both SMB and ice rheology (Raymond effect). The data show how arch amplitudes decrease as along-ridge slope increases, emphasizing that the lateral positioning of radar cross-sections is important for the arch interpretation. Using the model with three rheologies (isotropic with n = 3,4.5 and anisotropic with n = 3), we show that Derwael Ice Rise is close to steady-state, but is best explained using ice anisotropy and moderate thinning. Our preferred, albeit notunique, scenario suggests that the ice divide has existed for at least 5000 years and lowered at approximately 0.03 m a−1 over the last 3400 years. Independent of the specific thinning scenario, our modeling suggests that Derwael Ice Rise has exhibited a local flow regime at least since the Mid-Holocene

Harvester-Forwarder and Harvester-Yarder Systems for Fuel Reduction Treatments

Two harvesting systems were compared for reducing fuel loadings in overstocked conifer stands in eastern Oregon; forest managers also set a high priority on minimizing soil disturbance. Both employed cut-to-length (CTL) harvesters; one used a forwarder and the other a small skyline yarder. Both systems produced very similar and acceptable results in terms of fuels reduction and soil disturbance, but at different stump-to-mill costs: $46/green ton for the forwarder system versus$80/green ton for the yarder system

CO21 234. Implantación trans apical de válvula aórtica: excelentes resultados en pacientes de alto riesgo

ObjetivosLa implantación transapical de válvulas aórticas es un método nuevo aplicable a pacientes de alto riesgo y estenosis grave de válvula aórtica. Un informe de nuestra experiencia inicial.MétodosDesde abril de 2008 fueron tratados 208 pacientes (edad 79±8 anos, media 36-99 años), con el método híbrido de implantación transapical de válvula aórtica. La media logística EuroSCORE (STS) fue de 40±20% (6-97%) y la media del STS score 21±16% (3-97%). Catorce pacientes ingresaron en shock cardiogénico. Operaciones combinadas fueron efectuadas en 30 pacientes. Intervención de coronarias con stent en 25 pacientes, corrección de ASD en un paciente, dilatación de estenosis pulmonar en un paciente. Aneurismectomía en dos pacientes.Implantación de stent en la arteria renal en un paciente.ResultadosEl éxito técnico de las operaciones fue del 99,5%, la mortalidad hospitalaria fue de 5,7% para todo el grupo, 21% para el grupo en shock cardiogénico. No hubo complicaciones neurológicas en ningún paciente. En el 6% de los pacientes operados hubo la necesidad de implantación de marcapasos. El análisis de regresión univariante demuestra que el shock cardiogénico, elevado B-type natriuretic peptide (BNP)-level, son claros indicadores para la mortalidad postoperatoria temprana (30 días después de la operación). Shock cardiogénico, New York Heart Association (NYHA) IV, altos scores de riesgo, insuficiencia renal grave, son factores independientes para la predicción de la mortalidad acumulativa.ConclusionesLa técnica de recambio transapical de válvulas aórticas reduce significativamente el riesgo operatorio en pacientes de alto riesgo en comparación con el método convencional de recambio valvular aórtico