NEA TDBIV project : preparation of a state-of-the-art report on thermodynamic data for cement

The program of work of the fourth phase of the OECD NEA Thermochemical Database Project (TDB-IV) contemplates a line of activity on the preparation of a state of the art report on cements. The present work aims at presenting the project, its aims and its limits

School Counselor Leadership: Illuminating the Lived Experiences of Principals who Utilize Counselors in Leadership

AbstractThe topic of principal–school counselor partnerships has been emerging over the last several decades. The American School Counselor Association (ASCA) helped introduce and streamline counselor roles and responsibilities in 1952 and has been advocating for schools to have comprehensive school counseling programs since. Despite articles, research, and ASCA’s work to promote school counselors as leaders in the school and the importance of a comprehensive school counseling program, a gap remains with respect to counselors working with principals to establish comprehensive school counseling programs from the principal’s perspective. To understand the principal’s experience, the study was conducted using eight principals at Recognized ASCA Model Program schools. Using semistructured interviews and thematic analysis coding, the purpose of this hermeneutic phenomenological study was to answer the following overarching question about the lived experiences of principals who utilize counselors in school leadership by helping to remove barriers for a more effective principal/counselor partnership. Findings suggest that when principals and counselors have better relationships, they experience an increase in understanding of each other’s roles, achieve a higher level of mutual respect, better communication which helps with better flow of day-to-day operations, and experience an increase in the potential to have a higher job satisfaction rate. This in turn has enormous social change implications, as better principal-counselor relationships improve opportunities for student success

School Counselor Leadership: Illuminating the Lived Experiences of Principals who Utilize Counselors in Leadership

AbstractThe topic of principal–school counselor partnerships has been emerging over the last several decades. The American School Counselor Association (ASCA) helped introduce and streamline counselor roles and responsibilities in 1952 and has been advocating for schools to have comprehensive school counseling programs since. Despite articles, research, and ASCA’s work to promote school counselors as leaders in the school and the importance of a comprehensive school counseling program, a gap remains with respect to counselors working with principals to establish comprehensive school counseling programs from the principal’s perspective. To understand the principal’s experience, the study was conducted using eight principals at Recognized ASCA Model Program schools. Using semistructured interviews and thematic analysis coding, the purpose of this hermeneutic phenomenological study was to answer the following overarching question about the lived experiences of principals who utilize counselors in school leadership by helping to remove barriers for a more effective principal/counselor partnership. Findings suggest that when principals and counselors have better relationships, they experience an increase in understanding of each other’s roles, achieve a higher level of mutual respect, better communication which helps with better flow of day-to-day operations, and experience an increase in the potential to have a higher job satisfaction rate. This in turn has enormous social change implications, as better principal-counselor relationships improve opportunities for student success

Microbiology in nuclear waste disposal: interfaces and reaction fronts

It is now generally acknowledged that microbial populations will be present within nuclear waste repositories and that the consequences of such activity on repository performance must be assessed. Various modelling approaches - based either on mass balance/thermodynamics or on kinetics - have been developed to provide scoping estimates of the possible development of these populations. Past work has focused on particular areas of the repository which can be considered relatively homogeneous and hence can be represented by some kind of ‘box' or ‘mixing tank'. In reality, however, waste repositories include a range of engineering materials (steel, concrete, etc.) which are emplaced at depth in a rock formation. Strong chemical gradients - of the type which may be exploited by lithoautotrophic microbial populations - are likely to be found at the contacts between different materials and at the interface between the engineered structures and the host rock. Over the long timescales considered, solute transport processes will cause the locations of strong chemical gradients to move, forming reaction fronts. The high-pH plume resulting from the leaching of cement/concrete in some repository types is a particularly important example of such a reaction front. Redox fronts, which may occur in different areas of all kinds of repositories, also play an important role and would be locations where microbial activity is likely to be significant. In this paper, the key microbial processes expected at (or around) interfaces and fronts will be discussed, with particular emphasis on the development of quantitative models. The applicability of the models used will be tested by considering similar fronts which can be found in natural system

Quantification of bone strength by intraoperative torque measurement: a technical note

Introduction: Bone strength describes the resistance of bone against mechanical failure. Bone strength depends on both the amount of bone and the bone's quality, and the bone strength may be looked upon as a relevant parameter to judge an osteosynthesis' stability. Information about bone strength was barely available intraoperatively in the past. The previous work of our group reported on development and laboratory evaluation of mechanical torque measurement as a method for the intraoperative quantification of bone strength. With the clinical series presented here we intend to verify that the im gesamten Text DensiProbe™ instrumentation for intraoperative torque measurement and the related measurement method are eligible for intraoperative use based on the following criteria: application of the method may not create complications, the measurement can be performed by the surgeon himself and may only cause a limited increase in the procedure time. Patients and methods: From December 2006 until May 2007 ten patients with a pertrochanteric femoral fracture or a lateral femoral neck fracture eligible for stabilization with DHS® were included in the study after having received informed consent. Any medication and comorbidity that might have influenced bone quality or bone mineral density (BMD) in these patients was documented. Bone strength was intraoperatively measured with DensiProbe®. Complications that were obviously related with torque measurement were documented as well as any deviation from the suggested procedure; 6 and 12 weeks postoperative follow-up included clinical and radiological examination. The time required for torque measurement, the overall operating time and the number of persons present in the operating room were protocolled. BMD values of the contralateral femoral neck were postoperatively assessed by dual energy X-ray absorptiometry (DEXA) and compared to intraoperative peak torque values measured by DensiProbe®. Results: No major complication was observed during intraoperative application of DensiProbe®by trained surgeons. The unintended extraction of the guide wire together with the torque measurement probe was reported only once and is looked upon as a minor complication. Fracture healing was uneventful in all patients. The mean time for torque measurement was 2.35±0.9min accounting for 2.2±1.1% of total surgery time. The presence of an additional person was not required to perform torque measurement but to protocol the data. There was a tendency towards correlation between BMD values of the femoral neck and intraoperative peak torque values. Discussion: The data presented clearly indicate that the DensiProbe® instrumentation and measurement principle are eligible for routine intraoperative use by trained surgeons. Interpretation of possible correlations between BMD values measured by means of DEXA and the Peak Torque values assessed by DensiProbe® has to be considered very carefully, because BMD and Peak Torque analyse bone at a different scale. Only within the framework of a multicenter study it will be possible to include a sufficient number of patients for calculation of the methods' predictive value towards implant failure and to verify acceptance of the method by the surgeon

Fixation principles in metaphyseal bone—a patent based review

Osteoporotic changes start in cancellous bone due to the underlying pathophysiology. Consequently, the metaphyses are at a higher risk of "osteoporotic” fracture than the diaphysis. Furthermore, implant purchase to fix these fractures is also affected by the poor bone quality. In general, researchers and developers have worked on three different approaches to address the problem of fractures to osteoporotic bone: adapted anchoring techniques, improved load distribution as well as transfer with angular stable screws, and augmentation techniques using bone substitutes. A patent-based review was performed to evaluate which ideas were utilized to improve fixation in osteoporotic, metaphyseal bone, especially in the proximal femur, and to analyze whether the concept had entered clinical use. Anchoring devices that are either extramedullary or intramedullary have a long clinical history. However, demanding surgical techniques and complications, especially in poor quality bone, are justification that such implants and their corresponding surgical techniques need to be improved upon. Expanding elements have been evaluated in the laboratory. The results are promising and the potential of this approach has yet to be fully exploited in the clinics. Internal fixators with angular stable screws open the door for many new anchorage ideas and have great potential for further optimization of load distribution and transfer. Augmentation techniques may improve anchorage in osteoporotic bone. However, the properties of bone substitute materials will need to be modified and improved upon in order to meet the demanding requirements. If we summarise the development process and the clinical use of implants to date, we have to clearly state that more factors than simply biomechanical advantage will determine the clinical success of a new fixation principle or a new implant. Instead, fracture treatment of patients with osteoporosis really needs an interdisciplinary approach

Systems analysis of gaze stabilization behaviour and imaging of motor systems in the blowfly calliphora

A fast and powerful gaze stabilization reflex supports self-motion es- timation and flight control in flies. Changes in body posture are conveyed by a variety of sensory modalities and compensated for by fast and accurate head movements. This thesis aims to further our understanding of the behavioural basis of compensatory head move- ments, and presents a first foray into the in vivo imaging of the motor systems that actuate these control reflexes. Major sensors that contribute to gaze stabilisation are the visual ocelli and compound eyes on the head, and the mechanosensory halteres on the thorax. The integration of visual feedback and mechanosensory feedforward control gives rise to a two-degree-of-freedom controller, a design which is extensively used in engineering applications. I per- formed a linear systems analysis of compensatory head roll in response to forced thorax oscillations in the fly. The feedforward pathway ex- hibited a high bandwidth and constant gain and reduced the response delay of the reflex. Large stability margins in the feedback pathway supplied by the compound eyes guaranteed stable behaviour in the face of response variability. The occlusion of the ocelli did not change the gain of the feedback pathway, but significantly reduced the la- tency. I investigated the use of iodine-enhanced computed x-ray microto- mography (microCT) to perform fast three-dimensional imaging of the neck and flight motor systems. Virtual dissections of major func- tional units illustrate the possibilities and limitations of microCT. To observe the configuration of motor systems in behaving flies I per- formed gated microtomography using hard x-rays at the TOMCAT beamline of the Swiss Light Source, a third generation synchrotron. While 3D tomograms of the neck motor system proved elusive, this thesis presents the first in vivo tomograms of the flight motor and wing hinge during tethered flight.Open Acces