No description available.

In two experiments the Weighted Salience Model (WSM) of conceptual combination was examined. Several of the hypotheses set forth in the WSM were evaluated, including the importance of salience of constituent features, differential interpretation strategies based on similarity, an initial reliance on the modifier as opposed to the head, and a context effect of salience reorganization. Results confirmed that the hierarchy of output dominance within constituent features was important in determining features in final combinations. Additionally, similar pairs were defined with property interpretations more frequently than were dissimilar pairs, and dissimilar pairs were defined with relation interpretations more frequently than were similar pairs. Context effects were demonstrated through the finding that target features were found more often in primed than unprimed pairs. The hypothesis of modifier superiority was not confirmed. These findings indicate that the WSM adds to the current understanding of conceptual combination through a reliance on output dominance and the importance of context. Despite these strengths, changes to the WSM may be necessary if future studies fail to support the importance of the modifier over the head noun.

This interpretive exploratory case study investigated the challenges and barriers to the multi-grade context in general, as well as to Information and Communication Technology (ICT) implementation in a multi-grade context. Possible solutions based on teacher perceptions were generated inductively within a three-level typology. The research took place in three phases. Pre-training data were gathered in the first phase, using an open-ended questionnaire (all participants: n=20); personal interviews (n=9); and two focus group interviews, which consisted of three participants per focus group. Training on the Intel® Teach ICT programme and the provision of laptops (one per teacher) constituted the second phase. The third phase included post-training data generation using an open-ended questionnaire (all participants) and two focus group interviews, which consisted of three participants per focus group, to elicit teacher perceptions of the training programme and their use of the laptops in the classroom after the training. The findings suggest that first order (school or meso level) challenges pertaining to multi-grade teaching relate to the lack of resources; curriculum challenges; learner related challenges; isolation, impact on communication and teaching; time constraints; and a work overload as a result of the multiple roles. Second order challenges (self or micro level) related to the perceived uncaring attitude of the Department of Basic Education that left teachers feeling hurt and neglected; the unpreparedness for the multi-grade context which demotivated teachers; and the negative perceptions the teachers had about their learners. Third order challenges (system level, beyond the school level or micro level) were related to the lack of Departmental support from officials; the lack of curriculum training for the multi-grade context; and the lack of support on various fronts. Regarding ICT related challenges, the findings suggest that first order barriers related to the lack of suitable infrastructure for ICT implementation; lack of peer support; lack of access to appropriate hardware and software; and lack of time. Second order barriers related to the negative beliefs in the self; negative perceptions about the learners’ ability to use the laptop; and negative beliefs related to teaching and learning. The third order barriers were related to the lack of support and assistance from the Department of Basic Education for ICT implementation. The findings suggest that the participants viewed the provisioning of enabling programmes for parents as an important solution to first order challenges, and a change in mindset as the most important solution for second order problems. Third order solutions included a “multi-grade Renaissance” towards a new model for multi-grade teaching; re-thinking the curriculum requirements regarding multi-grade teaching by the Department of Basic Education; increased support and training from the Department; incentives to teach with ICT in the multi-grade context; encouraging further research inmulti-grade teaching; providing sufficient resources; establishing partnerships with stakeholders; and the closure and merger of multi-grade schools. There was evidence that the laptops provided were used in a variety of ways after the Intel® Teach training by the participants, including email as a tool to communicate with their fellow multi-grade peers, which serve to break their sense of isolation. Quantitative data from the open-ended questionnaire confirmed an increase in the usage of the laptop after the Intel® Teach training intervention. Although the participants generally experienced the Intel teach training intervention as positive, they also identified negative experiences. These findings enabled the embedding of ‘self and sustainable support from stakeholders’ more explicitly in the professional teacher development ICT implementation framework of Du Plessis and Webb (2012b), which suggests that the Intel® Teach training intervention can be used as a vehicle to address ICT implementation within the multi-grade context. It is suggested that the Department of Basic Education should consider exposing all teachers to the Intel® Teach programme and assist multi-grade teachers by providing better on-going support and putting the necessary policies, implementation and infrastructure in place.

This study provides a comprehensive modeling evaluation of the dynamic stability of Long Combination Vehicles (LCVs) that are commonly operated on U.S. highways, using multibody dynamic simulations in MATLAB/Simulink®. The dynamic equations for a tractor with two trailers connected by an A-frame converter dolly (A-Dolly) are developed. The dynamic model is used for running MATLAB® simulations, with parameters that are obtained through measurements or obtained from other sources. The simulation results are verified using track test data to establish a baseline model. The baseline model is used for parametric studies to evaluate the effect of trailer cargo weight, center of gravity (CG) longitudinal location, and trailer wheelbase. The dynamic model is further used to analyze both single-trailer and double-trailer trucks through nondimensionalization. The nondimensionalization method has the added advantage of enabling studies that can more broadly apply to various truck configurations. The simulation results indicate that increasing the trailer wheelbase reduces rearward amplification due to the damping effect of the longer wheelbase. A larger momentum ratio due to increased trailer gross weight increases rearward amplification. The detailed models of pneumatic disc and drum brakes in LCVs, including the airflow delay and thermal characteristics, are also developed and are coupled with the articulated vehicle dynamic models. The disc and drum brake braking performance are evaluated and compared in straight-line braking and combined steering and braking at a 150-ft J-turn maneuver. In straight-line braking, the simulation results indicate that disc brakes provide significantly shorter braking distance than drum brakes at highway speeds on a dry road, mainly due to their larger braking torque. On a slippery road surface, however, the greater braking torque causes more frequent wheel lockup and ABS activation at higher speeds, and disc brakes do not provide a substantially shorter braking distance than drum brakes. The simulations also point out that the disc brakes' cooling capacity is higher than the drum brake, with the cooling efficiency heavily dependent on the airflow speed. At higher driving speeds, the airflow accelerates to a turbulent flow and increases the convection efficiency. For braking in-turn maneuvers, at higher entering speeds, disc brakes decelerate the vehicle slightly sooner and then scrub speed faster, resulting in better roll stability when compared with drum brakes. / Doctor of Philosophy / Long combination vehicles (LCVs) are the combination of a tractor and two or more trailers and have been widely used on U.S. highways for cargo transport. Although LCVs have a larger cargo volume and provide more modularity in transporting goods, at higher speeds, they can be more prone to rollovers and require longer stopping distances and space to maneuver from one lane of travel to another. This study investigates the dynamic stability of an LCV, A-double trailer that includes a tractor, two trailers, and a dolly through modeling and simulation. The dynamic equations of each vehicle unit are derived based on Newtonian Mechanics (i.e., F = ma). The dynamic models are tuned to match the track testing results for similar vehicles, performed by the Center for Vehicle Systems and Safety (CVeSS) at Virginia Tech in the past. A novel evaluation method that nondimensionalizes the equations is used to allow for ease of use for LCVs with different cargo weights, lengths, and other similar variations. The dimensionless parameters are the function of vehicle parameters and express the relationship among the magnitude of vehicle parameters. Using the nondimensionalized model, the study performs a frequency analysis of the effect of trailer cargo weight, CG longitudinal position, and trailer wheelbase on roll stability and rearward amplification. Rearward amplification is the ratio of peak lateral acceleration between the tractor and the rearmost trailer. Slow-sweeping sinusoidal steering from 0.01 Hz to 0.6 Hz is used for the simulation analysis. The simulation results show that by increasing the trailer wheelbase—the distance from the trailer kingpin to the axle—the vehicle is more laterally stable because the longer wheelbases make the trailer more resistive to spinning around. Additionally, the pneumatic disc and drum brake models and thermal models are developed and coupled with the vehicle dynamic model. The disc and drum brake braking performance are investigated during both straight-line braking and combined steering and braking in a curve. The disc brakes generate a greater brake torque compared with drum brakes, and as such can decelerate the vehicle more efficiently on dry road surfaces, particularly at higher speeds such as highway speeds. This improves avoidance during emergency stops and roll stability during traveling in a curve, such as at a highway exit. The disc brakes also have greater cooling capacity because they can transfer the generated heat to the air due to the greater airflow and turbulence caused naturally by their design. This greatly helps to keep the brakes cooler on the track and to improve their stopping efficiency.

This study examines multigrade teaching in selected schools in Canada and its implications for improving multigrade teaching in South Africa, where over 50 % of primary schools are multigrade and the teachers have not received preparation in multigrade teaching. The case study method was adopted because it allowed for 'an intensive, holistic description and analysis' of the multigrade classroom. The approach is interpretivist, based on the assumption that social phenomena are 'socially constituted' and 'valuationally based'. Research techniques included a literature review, interviews and observations. Four classrooms with grade combinations ranging from two grades to eight grades (Kindergarten to grade 7) were studied. Despite problems such as the lack of official recognition, inadequate teacher education and support - problems common to both Canada and South Africa - the Canadian teachers managed their classrooms effectively. This was indicated by their understanding of the children's needs, their integration of the curriculum for teaching across the grades and the learning areas, their use of effective instructional strategies and their involyement of parents in the classroom. A reason for their success may be that their teacher education includes child-centred, activity based approaches, integration of the curriculum, critical thinking, flexibility and effective instructional strategies, which they may adapt for effective multigrade teaching. The study found that successful multigrade teaching depended on the teacher. For South Africa, this may imply that intervention programmes should focus on relevant preparation and support for multigrade teachers. The emphasis on material resources in the implementation of Curriculum 2005 has not been balanced with adequate training on policy, curriculum and instructional strategies. Teacher education should include methodologies that are experiential, reflective and participatory. A variety of instructional strategies should be employed in the multigrade classroom. The respondents in the study believed further that multigrade teaching is more beneficial than single-grade teaching because it caters for the diversity of needs amongst children and allows for peer tutoring, thereby exploiting Vygotsky's theory of the 'zone of proximal development'. Thus, instead of viewing multigrade teaching as a temporary phenomenon, it should be viewed as an opportunity for improving school effectiveness.

International Telemetering Conference Proceedings / October 25-28, 1999 / Riviera Hotel and Convention Center, Las Vegas, Nevada / This paper introduces the development of an S-band miniaturized solid-state pulse transmitter. Four-way power combination technique is applied to raise output power. The output power of the RF pulse exceeds 500W, and the combined efficiency amounts to 90%. The transmitter has many other good characteristics, such as small dimensions, light weight, low power consumption, high duty factor and so on. Development of this transmitter will greatly improve the ability of telemetry. It will undoubtedly promote the application and development of pulse telemetry system.

No description available.

No description available.

Class of 2012 Abstract / Specific Aims: The incidence of non-response, recurrence, relapse, and rate of complications of Clostridium difficile infections treated with combination of metronidazole and vancomycin versus vancomycin or metronidazole alone over a one-year period by treatment and strain type (i.e. NAP1/BI/027) were evaluated. The incidence of mortality in patients with moderate to severe Clostridium difficile associated diarrhea prescribed metronidazole, vancomycin, or combination metronidazole plus vancomycin as initial therapy was also determined. Additionally, significant factors associated with the use of combination vancomycin-metronidazole as initial therapy for moderate to severe CDAD were characterized. Methods: T This retrospective medical record review has been approved by the Institutional Review Board. Adult patients with stool specimens tested for detection of Clostridium difficile toxin B by PCR between April 2010 and March 2011 at a tertiary care, academic medical center were evaluated. Patients were included in the study if diagnosed with moderate to severe disease and received either monotherapy with metronidazole, monotherapy with oral vancomycin, or combination therapy with metronidazole and oral vancomycin for at least 80% of the first 10 days of treatment. Patients who are discharged alive within 72 hours of admission or who received therapy for less than 48 hours were excluded. Main Results: All patients (N=411) with laboratory evidence of Clostridium difficile during the study time period were evaluated. A total of 26 subjects who received oral vancomycin monotherapy and 56 subjects who received oral vancomycin along with metronidazole for at least 80% of the first 10 days of treatment were identified. Of the subjects who received oral vancomycin monotherapy during the first ten days of therapy, 5 (19%) were classified has a treatment failure or died within the first 21 days of therapy and 5 (19%) had either a recurrence or reappearance of Clostridium difficile associated diarrhea between 22 and 65 days post start of therapy. Of the subjects who received a combination of oral vancomycin and metronidazole during the first 10 days of therapy, 14 (25%) were classified has a treatment failure or died within the first 21 days of therapy and 22 (39%) had either a recurrence or reappearance of Clostridium difficile associated diarrhea between 22 and 65 days post start of therapy. In the combination therapy group, 5 (9%) were reported to have an ileus, toxic megacolon, or necrotic bowel during the first 10 days of therapy. Conclusions: In this study, the subjects who received a combination of oral vancomycin and metronidazole had higher rates of clinical failure, death, and recurrence than subjects who received monotherapy. Current guideline statements recommend combination therapy only in patients with an ileus with Clostridium difficile-associated diarrhea.

Head and neck cancer is the sixth leading cancer worldwide. Head and neck squamous cell carcinoma (HNSCC) accounts for more than 90% of incident cases. Despite intense, multimodality treatment regimens for HNSCC including surgery, chemotherapy, and radiation, little progress has been made over the past 30 years in improving overall survival rates. Tumor cell death induced by both conventional and targeted chemotherapy is often mediated by the BCL-2 family-dependent mitochondrial apoptotic pathway. However, initiators of this apoptotic pathway, such as p53, are more than 50% of the time mutated or deleted in HNSCC rendering the disease refractory to treatment. To counter such resistance, direct therapeutic targeting of the BCL-2 family is conceptually appealing. For this purpose, we use three clinically-available drugs: cisplatin, fenretinide, and ABT-263 (navitoclax). Both cisplatin and fenretinide are known to induce a BH3-only pro-apoptotic protein, Noxa, which binds to and inactivates multi-domain anti-apoptotic protein MCL-1 and release from its interaction with multi-domain pro-apoptotic protein BAK, followed by the phosphorylation via CDK2 for the proteasome-mediated degradation. Activated BAK can now go through conformational change for the oligomerization at the outer membrane of the mitochondria to release cytochrome c into the cytosol and induce caspase-dependent apoptotic cell death. ABT-263 directly binds to multi-domain anti-apoptotic proteins, such as BCL-2 and BCL-XL, to inhibit their activity and leads to the activation of multi-domain pro-apoptotic protein BAX to induce apoptosis. We hypothesize that combining the Noxa-inducing drugs (cisplatin or fenretinide) along with ABT-263 can efficiently induce BAX and BAK activation and significantly increase cell death in HNSCC cells by simultaneously inhibiting the activity of MCL-1, BCL-2, and BCL-XL. Combination-induced treatments in four cell lines (HN8, HN30, HN31, and UMSCC1) tested led to significant increase in apoptotic cell death. Cisplatin and ABT-263 combined treatment is inducing the expression of Noxa and leading to increase in apoptosis in HN30, HN31, UMSCC1, but not HN8. Similarly, fenretinide and ABT-263 combined treatment is inducing the expression of Noxa in all four cell lines tested and is largely relying on expression of Noxa.