Tactical radio communications used in military applications hasstrict requirements regarding security and has to be operable inrough environments in which there may be disturbances and disruptionson a radio link. The performance of the Secure CommunicationInteroperability Protocol (SCIP) operating in an asynchronouscommunication network with various levels of packet loss isinvestigated and found inadequate mainly due to problems withcryptographic synchronization between the transmitting and receivingunits. The introduction of additional counter data to each datapacket remedies this problem and allows the receiving units to fillthe holes left by packet losses with filler packets, maintainingsynchronization. The audio quality can then be measured using thePerceptual Evaluation of Speech Quality (PESQ) algorithm.Measurements are performed in an emulated radio link with aconfigurable packet loss ratio developed by Saab. The results showthat parts of SCIP can be used alongside the counter solution withoutimpacting the audio quality. The insertion of filler packets is shownto have a positive effect on the audio quality, while aggregation ofpackets to conserve transmission data rate is shown to have anegative effect.

Background: Elevated blood glucose in patients undergoing cardiac surgery pose increased risks of sternal incision infections, kidney disease, irregular heartbeats, extended hospital stays, and death. Elevated blood glucose also increases the costs of healthcare from prolonged lengths of stay and increased complications. The Surgical Care Improvement Project (SCIP) #4 performance measure is used to evaluate achievement of a target blood glucose control < 200 milligram/deciliter (mg/dl) post cardiac surgery on postoperative days 1 and 2. In the institution where this study was carried out, blood sugar control in the cardiac surgery patient has presented a challenge. Purpose: The purpose of this practice inquiry was to identify patient characteristics and outcomes in cardiac surgery patients who met the SCIP #4 performance measure versus those patients who did not. Methods: A retrospective nested case-control design was used. Risk factors for postoperative hyperglycemia and in-hospital outcomes were compared between cardiac surgery patients who were SCIP #4 met defined as 6AM BG ≤ 200 mg/dl on postoperative days 1 and 2 and those that were SCIP #4 not met, defined as 6AM BG > 200 mg/dl on postoperative days 1 or 2. Results: Results from this study showed that preoperative hemoglobin AIC and history of diabetes were two major contributors for SCIP #4 not-met status. There was a trend towards a longer length of stay in the SCIP #4 not met group as compared to the met group (9.01 ± 7.33 versus 7.30 ± 4.93 days, respectively; p = . 096). Mortality was 3 times more prevalent in the SCIP #4 not met than the met group (6.2% versus 2.1%, respectively); however, this different did not reach statistical significance (p = .129). Renal failure was four-fold more frequent in patients who were SCIP #4 not-met than who were SCIP #4 met (13.6% vs. 4.1%, respectively; p = 0.003). Conclusions: Results from this study showed that SCIP #4 not met is associated with development of postoperative renal failure in the hospital and a trend towards longer length of stay. History of diabetes and preoperative hemoglobin AIC level should be taken into consideration when evaluating strategies for managing hyperglycemia. Future research is needed to study the relationship between SCIP #4 met status and long-term outcomes. The use of preoperative hemoglobin A1C to identify patients at high risk for uncontrolled postoperative glucose and plan effective glucose control should be studied. Such study may include implementing intravenous insulin on all patients with diabetes and elevated hemoglobin A1C levels and comparing the short and long term outcomes.

Cell cycle progression in Caulobacter crescentus depends on the master regulator, CtrA. During the transition from swarmer to stalk cell (G1 to S phase), CtrA is degraded by the AAA+ protease ClpXP and levels rise again in the predivisional stage. The focus of this work is to explore how cyclic, regulated degradation is controlled. CtrA is known to bind to the origin of replication, thereby suppressing replication, so we first asked if DNA binding had an effect on CtrA stability. CtrA is readily degraded by ClpXP on its own, but when bound to DNA containing the proper binding sites, degradation is inhibited. Stabilization is dependent on DNA binding, as CtrA mutants deficient in DNA binding show the same degradation regardless of addition of DNA, as does CtrA in the presence of a mutant origin sequence lacking CtrA binding sites. Looking closely at CtrA degradation in the presence of auxiliary factors suggests that higher order complex formation may be a mechanism of protecting critical cell cycle regulators from premature proteolysis. In vivo study of over-expression of CtrA mutants revealed that accumulation of non-degradable CtrA, CtrA-DD, perturbs the cell cycle, leading to filamentation and a G2 arrest. Over-expression of the DNA-binding domain alone showed filamentation but no G2 arrest, suggesting that CtrA-DD is detrimental for reasons including, but likely not limited to, its ability to bind DNA. Exogenously expressing other domains of CtrA may further elucidate the mechanism of its regulated degradation in vivo.

There are many real cases where a company needs to determine the price of its products so as to maximise its revenue or profit.<p>To do so, the company must consider customers' reactions to these prices, as they may refuse to buy a given product or service if its price is too high. This is commonly known in literature as a pricing problem.<p>This class of problems, which is typically bilevel, was first studied in the 1990s and is NP-hard, although polynomial algorithms do exist for some particular cases. Many questions are still open on this subject.<p><p>The aim of this thesis is to investigate mathematical properties of pricing problems, in order to find structural properties, formulations and solution methods that are as efficient as possible. In particular, we focus our attention on pricing problems over a network. In this framework, an authority owns a subset of arcs and imposes tolls on them, in an attempt to maximise his/her revenue, while users travel on the network, seeking for their minimum cost path.<p><p>First, we provide a detailed review of the state of the art on bilevel pricing problems. <p>Then, we consider a particular case where the authority is using an unit toll scheme on his/her subset of arcs, imposing either the same toll on all of them, or a toll proportional to a given parameter particular to each arc (for instance a per kilometre toll). We show that if tolls are all equal then the complexity of the problem is polynomial, whereas in case of proportional tolls it is pseudo-polynomial.<p>We then address a robust approach taking into account uncertainty on parameters. We solve some polynomial cases of the pricing problem where uncertainty is considered using an interval representation.<p><p>Finally, we focus on another particular case where toll arcs are connected such that they constitute a path, as occurs on highways. We develop a Dantzig-Wolfe reformulation and present a Branch-and-Cut-and-Price algorithm to solve it. Several improvements are proposed, both for the column generation algorithm used to solve the linear relaxation and for the branching part used to find integer solutions. Numerical results are also presented to highlight the efficiency of the proposed strategies. This problem is proved to be APX-hard and a theoretical comparison between our model and another one from the literature is carried out. / Doctorat en Sciences / info:eu-repo/semantics/nonPublished

Spinal cord injury (SCI) is an acquired physical disability through traumatic injuries such as car accidents and shooting incidents, and non-traumatic injury such as a tumour on the spinal cord, amongst others. Unlike other parts of the body, the spinal cord does not have the ability to repair itself if it is damaged. Consequently, a person who has acquired an SCI will have a physical disability and will be either a paraplegic – paralysis of the lower part of the body, including the legs, or a quadriplegic, which is paralysis of all four limbs. Acquiring a spinal cord injury (SCI) has devastating long-term negative outcomes for the injured person as well as his/her cohabiting partner on a physical, psychological, psychosocial and socio-economical level. Exposure to such prolonged adversity and resulting negative outcomes calls for resilience, namely the ability to positively adapt despite the adversity being exposed to. Not all individuals have the natural ability to “bounce back”, and consequently resilience promotion is imperative. In South Africa, the focus of service delivery in rehabilitation centres is mainly centred on the injured person and consequently the well-being of the spinal cord injured person’s partner (SCIPP) is neglected. Little information is available on resilience-promoting programmes for SCIPPs; thus the main aim of this study was to design and develop a group resilience-promoting programme (GRPP) for SCIPPs. The researcher mainly followed a qualitative research approach and included a small quantitative component. In the context of applied research, an intervention research model comprising six phases was employed. Phase 1, Problem analysis and project planning, was reported on in section A. Manuscript 1 reports on phase 2 (information gathering and synthesis), and consists of a qualitative research synthesis, and mainly aimed at organizing and synthesizing previous research on resilience-promoting processes in order to inform the design and development of a group resilience-promoting programme (GRPP) for SCIPPs. After a systematic review and quality appraisal a total of 74 papers were selected to be quality appraised after abstracts and titles were assessed for relevance. Twenty-one studies were included and synthesized where after an outline for the content of a GRPP for SCIPPs was formulated. Conclusions and recommendations highlight that the formulated GRPP for SCIPPs needs to be further developed into an intervention that could be implemented with SCIPPs. As such, the researcher therefore proceeded with the study (see manuscript 2), aiming in developing small-group programme content and activities (using knowledge gathered from pre-existing interventions; resilience literature; consultations with experts; people living with spinal cord injury (SCI) and personal experience) to promote resilience in SCIPPs. By means of purposive sampling six advisory panel members from a diverse background were interviewed before and after the pilot study with two SCIPPs and one observer to contribute towards the further development of the GRPP for SCIPPs. A six-session GRPP for SCIPPs was formulated, including the following: (1) Information on SCI and resilience; (2) Help SCIPPs understand that their reactions to/emotions regarding these huge changes are normal; (3) Caretaking and support; (4) My dual role; (5) Own caretaking by SCIPPs; and (6) Termination and way forward. The newly developed GRPP for SCIPPs however had to be formally evaluated. Recommendations were made by professionals in the field that the GRPP for SCIPPs should first be subjected to peer review prior to implementing it with the target population. Therefore in manuscript 3 (reporting on phase 5 – evaluation ) the evaluation purpose was to subject the GRPP for SCIPPs to peer review by means of an empirical study with professional role-players (social workers and psychologists) in the field of spinal cord injury, prior to exhibiting it to the target population. The six group sessions were presented to professional role-players (n=12) working within the field of SCI during two 2-day workshops, whereby they were requested to evaluate the content and procedural elements of the GRPP for SCIPPs mainly by means of qualitative research, with a small numerical (quantitative) component. Thematic content analysis and basic descriptive statistics were employed. Overall positive feedback regarding the newly developed intervention was received, with suggested adjustments that needed to be made to the GRPP for SCIPPs prior to formal evaluation with the target group. The GRPP for SCIPPs will further be subjected to expert review in other provinces in South Africa, as the current participants were all from Gauteng. Furthermore, postgraduate students will be recruited to test the programme with the target-population in South Africa for possible further improvement and suggestions, as well as possible expansion to adjust this intervention to meet the needs of male SCIPPs; SCIPs themselves; children of a parent/s living with SCI; and also for post-injury cohabiting relationships, as this intervention might be a starting point for above-mentioned research-opportunities.

Spinal cord injury (SCI) is an acquired physical disability through traumatic injuries such as car accidents and shooting incidents, and non-traumatic injury such as a tumour on the spinal cord, amongst others. Unlike other parts of the body, the spinal cord does not have the ability to repair itself if it is damaged. Consequently, a person who has acquired an SCI will have a physical disability and will be either a paraplegic – paralysis of the lower part of the body, including the legs, or a quadriplegic, which is paralysis of all four limbs. Acquiring a spinal cord injury (SCI) has devastating long-term negative outcomes for the injured person as well as his/her cohabiting partner on a physical, psychological, psychosocial and socio-economical level. Exposure to such prolonged adversity and resulting negative outcomes calls for resilience, namely the ability to positively adapt despite the adversity being exposed to. Not all individuals have the natural ability to “bounce back”, and consequently resilience promotion is imperative. In South Africa, the focus of service delivery in rehabilitation centres is mainly centred on the injured person and consequently the well-being of the spinal cord injured person’s partner (SCIPP) is neglected. Little information is available on resilience-promoting programmes for SCIPPs; thus the main aim of this study was to design and develop a group resilience-promoting programme (GRPP) for SCIPPs. The researcher mainly followed a qualitative research approach and included a small quantitative component. In the context of applied research, an intervention research model comprising six phases was employed. Phase 1, Problem analysis and project planning, was reported on in section A. Manuscript 1 reports on phase 2 (information gathering and synthesis), and consists of a qualitative research synthesis, and mainly aimed at organizing and synthesizing previous research on resilience-promoting processes in order to inform the design and development of a group resilience-promoting programme (GRPP) for SCIPPs. After a systematic review and quality appraisal a total of 74 papers were selected to be quality appraised after abstracts and titles were assessed for relevance. Twenty-one studies were included and synthesized where after an outline for the content of a GRPP for SCIPPs was formulated. Conclusions and recommendations highlight that the formulated GRPP for SCIPPs needs to be further developed into an intervention that could be implemented with SCIPPs. As such, the researcher therefore proceeded with the study (see manuscript 2), aiming in developing small-group programme content and activities (using knowledge gathered from pre-existing interventions; resilience literature; consultations with experts; people living with spinal cord injury (SCI) and personal experience) to promote resilience in SCIPPs. By means of purposive sampling six advisory panel members from a diverse background were interviewed before and after the pilot study with two SCIPPs and one observer to contribute towards the further development of the GRPP for SCIPPs. A six-session GRPP for SCIPPs was formulated, including the following: (1) Information on SCI and resilience; (2) Help SCIPPs understand that their reactions to/emotions regarding these huge changes are normal; (3) Caretaking and support; (4) My dual role; (5) Own caretaking by SCIPPs; and (6) Termination and way forward. The newly developed GRPP for SCIPPs however had to be formally evaluated. Recommendations were made by professionals in the field that the GRPP for SCIPPs should first be subjected to peer review prior to implementing it with the target population. Therefore in manuscript 3 (reporting on phase 5 – evaluation ) the evaluation purpose was to subject the GRPP for SCIPPs to peer review by means of an empirical study with professional role-players (social workers and psychologists) in the field of spinal cord injury, prior to exhibiting it to the target population. The six group sessions were presented to professional role-players (n=12) working within the field of SCI during two 2-day workshops, whereby they were requested to evaluate the content and procedural elements of the GRPP for SCIPPs mainly by means of qualitative research, with a small numerical (quantitative) component. Thematic content analysis and basic descriptive statistics were employed. Overall positive feedback regarding the newly developed intervention was received, with suggested adjustments that needed to be made to the GRPP for SCIPPs prior to formal evaluation with the target group. The GRPP for SCIPPs will further be subjected to expert review in other provinces in South Africa, as the current participants were all from Gauteng. Furthermore, postgraduate students will be recruited to test the programme with the target-population in South Africa for possible further improvement and suggestions, as well as possible expansion to adjust this intervention to meet the needs of male SCIPPs; SCIPs themselves; children of a parent/s living with SCI; and also for post-injury cohabiting relationships, as this intervention might be a starting point for above-mentioned research-opportunities.