3D-Effects in Total Stability Evaluations

This master’s dissertation has been performed in cooperation with Tyréns and the Dept. of Construction Sciences, LTH. We have investigated if it is possible to increase the total stability for excavations with retaining structures and if each side of an excavation could be treated as a separate 2D-case with additional theories to approximate its 3D-effects. End-surface theories from the Commission on slope stability (CSS) report 3:95 could possibly be used to consider 3D-effects although they are originally created for slopes without structural support. Neither is there any information regarding the interaction between these separated 2D-systems. The intention of this master’s dissertation is to validate that these theories mentioned can be used and that it is reasonable doing so. It is done by evaluating three different kinds of systems namely > Generalised sloped excavations where corners and thus interactions between sides are introduced into the model but without structure to examine endsurface- and additional 3D-effects where the applied theories are valid. > Generalised excavation with retaining structure to determine corner-, endsurface- and structural effects. > The theories evaluated are then applied to a real life case with material- and structural parameters evaluated from the Västlänken project. Here the possibility of excavating a 70x70x15 m (length, width, depth) is investigated. For all of the modelling steps; analytical and numerical calculations have been performed, where Slope/W has been used to aid the analytical calculations and Plaxis- 2D and 3D have been used for 2D and 3D modelling. Evident in the results assembled in this work is that 2D-analytical calculations underestimates the total stability (FS) for an excavation when compared to numerical calculations. Applying the end surface theory from CSS report 3:95 generates results similar to the ones generated by 3D modelling, but on the safe side. This final comparison was made without considering the stabilising effect that can be accounted for due to the retaining structural connections in the corners

En studie om hur olika röstkvaliteter i kombination med bakgrundsbuller påverkar barns språkförståelse

Föreliggande studie baseras på en jämförelse mellan två likvärdiga grupper av barn. Syftet var att undersöka om barns språkförståelse påverkas mer av en dysfonisk (hes) röst i kombination med bakgrundsbuller jämfört med en typisk (funktionell) röst i kombination med bakgrundsbuller. Syftet var även att ta reda på barnens subjektiva upplevelse om lärarens röstkvalitet, kombinationen röstkvalitet och bakgrundsbuller samt ”frökens sätt att vara”. Vidare undersöktes sambandet mellan barnens kognitiva kapacitet och hur de presterade på språkförståelsetestet. I studien ingick 98 barn som grupperades efter kön innan testningen initierades. Testsituationen bestod av tre deltest som undersökte förmågorna: Arbetsminne, exekutiva funktioner och språkförståelse samt en intervju om barnens subjektiva upplevelse. Språkförståelsetestet var en digitaliserad version av TROG-2 och bestod av två olika förinspelade röstkvaliteter i kombination med bakgrundsbuller varav den ena gruppen lyssnade till en typisk röst och den andra till en dysfonisk röst. Resultatet av testningen visade signifikanta skillnader gällande barnens subjektiva upplevelse av röstkvaliteten, kombinationen röstkvalitet och bakgrundsbuller samt ”frökens sätt att vara”. Barnen som lyssnade till den dysfoniska rösten skattade nämligen den mer negativt och använde fler negativa ordval jämfört med den andra gruppen. Dock fanns det ingen signifikant skillnad mellan grupperna enligt resultaten av arbetsminneskapacitet, exekutiva funktioner eller språkförståelse. Starka samband visades mellan barnens kognitiva kapacitet och hur de presterade på språkförståelsetestet. Resultaten är viktiga eftersom varje elev förtjänar en optimal lärandemiljö och detta kan vi närma oss genom att röstutbildning blir en obligatorisk del av lärarutbildningen

Physiologic regulation of heart rate and blood pressure involves connexin 36-containing gap junctions

Chronically elevated sympathetic nervous activity underlies many cardiovascular diseases. Elucidating the mechanisms contributing to sympathetic nervous system output may reveal new avenues of treatment. The contribution of the gap junctional protein connexin 36 (Cx36) to the regulation of sympathetic activity and thus blood pressure and heart rate was determined, using a mouse with specific genetic deletion of Cx36. Ablation of the Cx36 protein was confirmed in sympathetic preganglionic neurons of Cx36 knockout (KO) mice. Telemetric analysis from conscious Cx36 KO mice revealed higher variance in heart rate and blood pressure during rest and activity compared to wildtype (WT) mice, and smaller responses to chemoreceptor activation when anesthetized. In the working heart brainstem preparation of the Cx36 KO mouse, respiratory-coupled sympathetic nerve discharge was attenuated and responses to chemoreceptor stimulation and noxious stimulation were blunted compared to WT mice. Using whole cell patch recordings, sympathetic preganglionic neurons in spinal cord slices of Cx36 KO mice displayed lower levels of spikelet activity compared to WT mice, indicating reduced gap junction coupling between neurons. Cx36 deletion therefore disrupts normal regulation of sympathetic outflow with effects on cardiovascular parameters

Rapid sediment deposition and fine-scale strata formation in the Hudson estuary

Author Posting. © American Geophysical Union, 2004. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Journal of Geophysical Research 109 (2004): F02004, doi:10.1029/2003JF000096.A 9 month time series of tripod-mounted optical and acoustic measurements of sediment concentration and bed elevation was used to examine depositional processes in relationship to hydrodynamic variables in the Hudson River estuary. A series of cores was also taken directly under and adjacent to the acoustic measurements to examine the relation between the depositional processes and the resulting fine-scale stratigraphy. The measurements reveal that deposition occurs as a result of sediment flux convergence behind a salinity front and that the accumulation rates are sufficient to deposit up to 25 cm of new high-porosity sediment in a single ebb-tidal phase. Subsequent dewatering and erosion reduces the thickness of the initial deposit to several centimeters. These depositional events were only observed on spring tides. Ten depositional events during two spring tidal cycles produced a seasonal deposit of 18 cm, consistent with estimates of seasonal deposition from cores. A proxy for near-bed suspended grain size variations was estimated from the combined acoustic and optical measurements, implying that the erosional processes resuspend only the finer-grained sediments, thus leaving behind silt and very fine grained sand beds. The thickness of the deposited homogenous clayey silt beds, and the vertical separation between beds interlaminated with silt and very fine sand, are roughly consistent with the acoustic measurements of changes in bed elevations during deposition and erosion. The variability in individual bed thickness is the result of variations of processes over an individual tidal cycle and is not a product of variations over the spring neap fortnightly timescale.The authors would like to acknowledge the Hudson River Foundation, who provided funding for this work under grant 009/00A

Ganglion Cell Adaptability: Does the Coupling of Horizontal Cells Play a Role?

Background: The visual system can adjust itself to different visual environments. One of the most well known examples of this is the shift in spatial tuning that occurs in retinal ganglion cells with the change from night to day vision. This shift is thought to be produced by a change in the ganglion cell receptive field surround, mediated by a decrease in the coupling of horizontal cells. Methodology/Principal Findings: To test this hypothesis, we used a transgenic mouse line, a connexin57-deficient line, in which horizontal cell coupling was abolished. Measurements, both at the ganglion cell level and the level of behavioral performance, showed no differences between wild-type retinas and retinas with decoupled horizontal cells from connexin57-deficient mice. Conclusion/Significance: This analysis showed that the coupling and uncoupling of horizontal cells does not play a dominant role in spatial tuning and its adjustability to night and day light conditions. Instead, our data suggest that anothe

The pancreatic beta cell surface proteome

The pancreatic beta cell is responsible for maintaining normoglycaemia by secreting an appropriate amount of insulin according to blood glucose levels. The accurate sensing of the beta cell extracellular environment is therefore crucial to this endocrine function and is transmitted via its cell surface proteome. Various surface proteins that mediate or affect beta cell endocrine function have been identified, including growth factor and cytokine receptors, transporters, ion channels and proteases, attributing important roles to surface proteins in the adaptive behaviour of beta cells in response to acute and chronic environmental changes. However, the largely unknown composition of the beta cell surface proteome is likely to harbour yet more information about these mechanisms and provide novel points of therapeutic intervention and diagnostic tools. This article will provide an overview of the functional complexity of the beta cell surface proteome and selected surface proteins, outline the mechanisms by which their activity may be modulated, discuss the methods and challenges of comprehensively mapping and studying the beta cell surface proteome, and address the potential of this interesting subproteome for diagnostic and therapeutic applications in human disease