Crack growth and development of fracture zones in plain concrete and similar materials

[abstract missing

Mechanisms underlying cortical resonant states: implications for levodopa-induced dyskinesia

A common observation in recordings of neuronal activity from the cerebral cortex is that populations of neurons show patterns of synchronized oscillatory activity. However, it has been suggested that neuronal synchronization can, in certain pathological conditions, become excessive and possibly have a pathogenic role. In particular, aberrant oscillatory activation patterns have been implicated in conditions involving cortical dysfunction. We here review the mechanisms thought to be involved in the generation of cortical oscillations and discuss their relevance in relation to a recent finding indicating that high-frequency oscillations in the cerebral cortex have an important role in the generation of levodopa-induced dyskinesia. On the basis of these insights, it is suggested that the identification of physiological changes associated with symptoms of disease is a particularly important first step toward a more rapid development of novel treatment strategies

Arbetsbehov och kostnader för dikor i utedrift utan ligghall jämfört med traditionell djurhållning med byggnader

Det svenska lantbruket är bara en av många näringar i Sverige där kostnaderna för verksamheten har ökat kraftigt den senaste tiden. Detta har gjort att många lantbrukare har det tuffare rent ekonomiskt när det kommer till investeringar. För dikoproducenter är det redan tufft sen innan då inkomsterna kontra utgifterna är relativt lika. För att dikoproducenterna ska få det bättre ekonomiskt bör de undersöka andra sätt om hur de kan hålla djuren under vinterperioden. Utedrift utan ligghall är ett bra och ekonomiskt djurhållningssystem för lantbrukare förutsatt att de har rätt marker till det. I detta arbete kommer den som är intresserad av utedrift utan ligghall få ta del utav information gällande utedrift utan ligghall samt djurhållning i byggnader. Det kommer att presenteras två kvantitativa undersökningar som har gjorts för vartdera system via enkäter. Utifrån undersökningen får man ta del utav arbetsbehovet för varje system samt vissa ekonomiska aspekter exempelvis investeringskostnad för byggnaden respektive för stängslet. Bland de viktigaste resultaten är att arbetstiden för den dagliga skötseln av dikor i utedrift utan ligghall i medeltal tar 1,8 minuter per diko och dag under vinterperioden och 2 minuter per diko och dag för system med djurstall. Det är stor variation i arbetstid mellan minsta och högsta arbetstid för båda systemen. Det ska också nämnas att det var stor variation för investeringskostnaden per dikoplats för de olika systemen. Systemet som hade högst investeringskostnad per dikoplats var ett system med byggnader med en kostnad på 47 095 kr medan ett system med utedrift utan ligghall hade en kostnad på 3 900 kr per diko. Slutsatsen är att det är mer ekonomiskt att ha utedrift utan ligghall eftersom investeringskostnaden är lägre per djur jämfört kostnaden som är för djur som hålls i djurstall. Dessutom kan lantbrukare som har utedrift kan spara tid med sitt system jämfört om de skulle ha djuren i en byggnad då de har färre arbetsmoment kring djuren.Swedish agriculture is just one of many industries in Sweden where the costs of operations have increased sharply recently. This has meant that many farmers have a tougher financial time when it comes to investments. For beef cow producers, this is already tough since before due to the income versus expenses are relatively equal. For the beef cow producers to be better off financially, they should check other ways about how they can keep the animals during the winter period. Ranching without any buildings is a good and economical animal husbandry system for farmers, provided they have the right land for it. In this work anyone who is interested in ranching without any buildings will be able to take part in information regarding ranching without any buildings and keeping animals in buildings. Two quantitative studies have been done for each system with the help of surveys. Based on the surveys, one can take part in the work requirements for each system as well as certain financial aspects such as the investment cost of the building compared with the fence. Among the most important results is that the working time for the daily care of the cows in outdoor operation without a lying shed takes an average of 1,8 minutes per cow and day during the winter period and 2 minutes per cow and day för systems with animal stalls. There is a large variation in working hours between the minimum and maximum working hours for both systems. It should also be mentioned that there was a large variation in the investment cost per cow place for the different systems. The system with the highest investment cost per cow place was a system with buildings with a cost of 47 095 SEK, while an outdoor operation without a lying shed had a cost of 3 900 SEK per cow. The conclusion is that it is more economical to have a ranch without any buildings. As the cost is lower per animal compared to the cost of animals kept in buildings. And that the farmers that have this kind of system can save time compared to if they would keep the animals in a building as they have less time around the animals

Influence of Plastic Dissipation on Apparent Fracture Energy Determined by a Three-Point Beding Test

A three-point bending test used for determining the fracture energy in modus I for wood perpendicular to the grain is studied, If the height of the specimen is varied, the results show a size effect, The specimens used in testing have been analyzed by finite element calculations with an anisotropic elasto-plastic material model in order to determine the influence of plastic dissipation. Analysis has been performed for three sizes of specimens where the height and length have been varied. The computational results are compared with experimental results

Conversion of helical tomotherapy plans to step-and-shoot IMRT plans-Pareto front evaluation of plans from a new treatment planning system

Purpose: The resulting plans from a new type of treatment planning system called SharePlan (TM) have been studied. This software allows for the conversion of treatment plans generated in a TomoTherapy system for helical delivery, into plans deliverable on C-arm linear accelerators (linacs), which is of particular interest for clinics with a single TomoTherapy unit. The purpose of this work was to evaluate and compare the plans generated in the SharePlan system with the original TomoTherapy plans and with plans produced in our clinical treatment planning system for intensity-modulated radiation therapy (IMRT) on C-arm linacs. In addition, we have analyzed how the agreement between SharePlan and TomoTherapy plans depends on the number of beams and the total number of segments used in the optimization. Methods: Optimized plans were generated for three prostate and three head-and-neck (H&N) cases in the TomoTherapy system, and in our clinical treatment planning systems (TPS) used for IMRT planning with step-and-shoot delivery. The TomoTherapy plans were converted into step-and-shoot IMRT plans in SharePlan. For each case, a large number of Pareto optimal plans were created to compare plans generated in SharePlan with plans generated in the Tomotherapy system and in the clinical TPS. In addition, plans were generated in SharePlan for the three head-and-neck cases to evaluate how the plan quality varied with the number of beams used. Plans were also generated with different number of beams and segments for other patient cases. This allowed for an evaluation of how to minimize the number of required segments in the converted IMRT plans without compromising the agreement between them and the original TomoTherapy plans. Results: The plans made in SharePlan were as good as or better than plans from our clinical system, but they were not as good as the original TomoTherapy plans. This was true for both the head-and-neck and the prostate cases, although the differences between the plans for the latter were small. The evaluation of the head-and-neck cases also showed that the plans generated in SharePlan were improved when more beams were used. The SharePlan Pareto front came close to the front for the TomoTherapy system when a sufficient number of beams were added. The results for plans generated with varied number of beams and segments demonstrated that the number of segments could be minimized with maintained agreement between SharePlan and TomoTherapy plans when 10-19 beams were used. Conclusions: This study showed (using Pareto front evaluation) that the plans generated in SharePlan are comparable to plans generated in other TPSs. The evaluation also showed that the plans generated in SharePlan could be improved with the use of more beams. To minimize the number of segments needed in a plan with maintained agreement between the converted IMRT plans and the original TomoTherapy plans, 10-19 beams should be used, depending on target complexity. SharePlan has proved to be useful and should thereby be a time-saving complement as a backup system for clinics with a single TomoTherapy system installed alongside conventional C-arm linacs. (C) 2011 American Association of Physicists in Medicine. [DOI: 10.1118/1.3592934

Haematological toxicity in adult patients receiving craniospinal irradiation - Indication of a dose-bath effect.

The purpose of this study was to investigate the correlation between the haematological toxicity observed in patients treated with craniospinal irradiation, and the dose distribution in normal tissue, specifically the occurrence of large volumes exposed to low dose

A system for automated tracking of motor components in neurophysiological research

In the study of motor systems it is often necessary to track the movements of an experimental animal in great detail to allow for interpretation of recorded brain signals corresponding to different control signals. This task becomes increasingly difficult when analyzing complex compound movements in freely moving animals. One example of a complex motor behavior that can be studied in rodents is the skilled reaching test where animals are trained to use their forepaws to grasp small food objects, in many ways similar to human hand use. To fully exploit this model in neurophysiological research it is desirable to describe the kinematics at the level of movements around individual joints in 3D space since this permits analyses of how neuronal control signals relate to complex movement patterns. To this end, we have developed an automated system that estimates the paw pose using an anatomical paw model and recorded video images from six different image planes in rats chronically implanted with recording electrodes in neuronal circuits involved in selection and execution of forelimb movements. The kinematic description provided by the system allowed for a decomposition of reaching movements into a subset of motor components. Interestingly, firing rates of individual neurons were found to be modulated in relation to the actuation of these motor components suggesting that sets of motor primitives may constitute building blocks for the encoding of movement commands in motor circuits. The designed system will, thus, enable a more detailed analytical approach in neurophysiological studies of motor systems

Characterization of long-term motor deficits in the 6-OHDA model of Parkinson's disease in the common marmoset.

Research aimed at developing new therapies for Parkinson's disease (PD) critically depend on valid animal models of the disease that allows for repeated testing of motor disabilities over extended time periods. We here present an extensive characterization of a wide range of motor symptoms in the 6-OHDA marmoset model of PD when tested over several months. The severity of motor deficits was quantified in two ways: (i) through manual scoring protocols appropriately adapted to include species specific motor behavior and (ii) using automated quantitative motion tracking based on image processing of the digital video recordings. We show that the automated methods allow for rapid and reliable characterization of motor dysfunctions, thus complementing the manual scoring procedures, and that robust motor symptoms lasting for several months could be induced when using a two-stage neurotoxic lesioning procedure involving one hemisphere at a time. This non-human primate model of PD should therefore be well suited for long-term evaluation of novel therapies for treatment of PD