Fabrication of controlled-porosity metals Patent

Production method for manufacturing porous tungsten bodies from tungsten powder particle

An empirical Bayesian analysis applied to the globular cluster pulsar population

We describe an empirical Bayesian approach to determine the most likely size of an astronomical population of sources of which only a small subset are observed above some limiting flux density threshold. The method is most naturally applied to astronomical source populations at a common distance (e.g.,stellar populations in globular clusters), and can be applied even to populations where a survey detects no objects. The model allows for the inclusion of physical parameters of the stellar population and the detection process. As an example, we apply this method to the current sample of radio pulsars in Galactic globular clusters. Using the sample of flux density limits on pulsar surveys in 94 globular clusters published by Boyles et al., we examine a large number of population models with different dependencies. We find that models which include the globular cluster two-body encounter rate, $\Gamma$, are strongly favoured over models in which this is not a factor. The optimal model is one in which the mean number of pulsars is proportional to $\exp(1.5 \log \Gamma)$. This model agrees well with earlier work by Hui et al. and provides strong support to the idea that the two-body encounter rate directly impacts the number of neutron stars in a cluster. Our model predicts that the total number of potentially observable globular cluster pulsars in the Boyles et al. sample is 1070$^{+1280}_{-700}$, where the uncertainties signify the 95% confidence interval. Scaling this result to all Galactic globular clusters, and to account for radio pulsar beaming, we estimate the total population to be 2280$^{+2720}_{-1490}$.Comment: 8 pages, 6 figures, 3 tables, corrected a few minor formatting errors which have also been submitted as an erratum to MNRA

Alloy ionizer fabrication Summary report

Fabrication methods of porous refractory ionizers from spherical powders of iridium-tungsten, and rhenium-tungste

Assessing the impact of co-occurrence frequency and diversity in statistical learning accounts of language processing

Language is heralded as one of the foremost human achievements and is vital in scaffolding the successful development of many other skills. Yet, the mechanism by which language is acquired is still poorly understood. One possible account is Statistical Learning Theory, an explanation of language acquisition that has grown in popularity over the past three decades. The central tenet of Statistical Learning Theory is that learners are guided by statistical regularities in their environment and can utilise these to develop an implicit understanding of their natural language. Current theory holds that transitional probabilities are the best predictor of learner performance in statistical learning tasks. However, little has been done to investigate alternative statistical measures. This thesis presents two such metrics: Bigram frequency and bigram diversity and contrasts them with transitional probability in predicting task performance. Through the repurposing of primed lexical decision and sequence learning tasks, I present a novel approach to examining the impact of statistical priming on task performance in a naturalistic dataset. Model comparison using Bayesian multilevel modelling suggests that transitional probability is not as reliable a predictor as was previously believed. Moreover, I demonstrate that bigram frequency may represent a better metric for predicting task performance in these tasks. The current work highlights the importance of considering alternative metrics of statistical regularity when describing the underlying mechanisms of language acquisition and showcases alternative methods of examining statistical learning performance

Neuromechanical measurement of motor impairments in relation to upper limb activity limitations after stroke

Loss of upper-limb function is a problem following stroke. Recent research has led to the emergence of new treatments but progress is hampered by lack of reliable objective measures of impairment, and understanding of the underlying impairment mechanisms associated with loss and recovery of functional activity. The aim of this research was to identify, using neuromechanical measurement methods, inter-relationships between motor impairments, and correlates of motor impairments with functional activity limitation in the upper limb of acute and chronic stroke survivors.An instrumented rig has been developed to measure impairments: muscle weakness, active range of movement, motor control accuracy in rhythmic and discrete tracking tasks, spasticity, coactivation, contracture and non-neural stiffness. In pilot studies, signal processing and data analysis techniques have been used to generate novel, clinically and physiologically relevant indices to quantify impairments. In a Main Study, 13 older impaired participants in the acute phase post-stroke, 13 in the chronic phase 14 age-matched unimpaired participants underwent rig assessments and performed a test of upper limb activity. A sub-group of impaired participants were tested on two days for test-retest reliability evaluation.Statistical tests have confirmed the validity of the impairments to distinguish between acute and chronic patients and unimpaired individuals, except coactivation during discrete movements and non-neural stiffness. Repeatability coefficients for the active test indices have been presented as benchmark values for use in future trials. The muscle activation indices showed lower repeatability which highlights the challenge of using these to measure change over time. The impairments that contributed to lower motor control accuracy were reduced extensor weakness, delayed extensor onset timing, coactivation and smaller extension AROM and PROM; coactivation was more strongly associated with motor control accuracy than with spasticity or stiffness.The most important contributors to functional activity in the acute group was extensor weakness, and in the chronic group was motor control accuracy and coactivation (rhythmic task). Contracture was important contributor in both groups, and was associated with weakness and loss of active range of movement rather than spasticity. The findings support the notion that rehabilitation strategies should focus on increasing muscle strength and prevention of contracture. However, assessment of more complex impairments like motor control accuracy and coactivation may be crucial to better target therapy, especially in the later phases post-stroke

Parasitism in Calves

There is little information concerning the extent of parasitic infestation in cattle, particularly subclinical infestations. Relatively few experimental studies of parasitic infestations in cattle have been made. This is due, in part at least, to the high cost of cattle as experimental animals and the space required for conducting experiments on them. Internal parasites have long been recognized as a hazard in the production of sheep and swine but comparatively few livestock raisers realize that in many instances parasites cause serious losses in cattle. Even when parasites are present in sufficient numbers to produce clinical symptoms, these symptoms are often confused with and ascribed to other conditions. This is particularly true in those areas where parasitism occurs in conjunction with malnutrition

Exploiting the full power of temporal gene expression profiling through a new statistical test: Application to the analysis of muscular dystrophy data

Background: The identification of biologically interesting genes in a temporal expression profiling dataset is challenging and complicated by high levels of experimental noise. Most statistical methods used in the literature do not fully exploit the temporal ordering in the dataset and are not suited to the case where temporal profiles are measured for a number of different biological conditions. We present a statistical test that makes explicit use of the temporal order in the data by fitting polynomial functions to the temporal profile of each gene and for each biological condition. A Hotelling T2-statistic is derived to detect the genes for which the parameters of these polynomials are significantly different from each other. Results: We validate the temporal Hotelling T2-test on muscular gene expression data from four mouse strains which were profiled at different ages: dystrophin-, beta-sarcoglycan and gammasarcoglycan deficient mice, and wild-type mice. The first three are animal models for different muscular dystrophies. Extensive biological validation shows that the method is capable of finding genes with temporal profiles significantly different across the four strains, as well as identifying potential biomarkers for each form of the disease. The added value of the temporal test compared to an identical test which does not make use of temporal ordering is demonstrated via a simulation study, and through confirmation of the expression profiles from selected genes by quantitative PCR experiments. The proposed method maximises the detection of the biologically interesting genes, whilst minimising false detections. Conclusion: The temporal Hotelling T2-test is capable of finding relatively small and robust sets of genes that display different temporal profiles between the conditions of interest. The test is simple, it can be used on gene expression data generated from any experimental design and for any number of conditions, and it allows fast interpretation of the temporal behaviour of genes. The R code is available from V.V. The microarray data have been submitted to GEO under series GSE1574 and GSE3523

Small Engine Component Technology (SECT)

A study of small gas turbine engines was conducted to identify high payoff technologies for year-2000 engines and to define companion technology plans. The study addressed engines in the 186 to 746 KW (250 to 1000 shp) or equivalent thrust range for rotorcraft, commuter (turboprop), cruise missile (turbojet), and APU applications. The results show that aggressive advancement of high payoff technologies can produce significant benefits, including reduced SFC, weight, and cost for year-2000 engines. Mission studies for these engines show potential fuel burn reductions of 22 to 71 percent. These engine benefits translate into reductions in rotorcraft and commuter aircraft direct operating costs (DOC) of 7 to 11 percent, and in APU-related DOCs of 37 to 47 percent. The study further shows that cruise missile range can be increased by as much as 200 percent (320 percent with slurry fuels) for a year-2000 missile-turbojet system compared to a current rocket-powered system. The high payoff technologies were identified and the benefits quantified. Based on this, technology plans were defined for each of the four engine applications as recommended guidelines for further NASA research and technology efforts to establish technological readiness for the year 2000

Stimulating a Gradual and Progressive Shift to Personalize Learning for All: There is Magic in the Middle

This essay contends that personalized professional learning can support the shift towards a culture of personalized learning at the middle school level, with the potential to make a district-wide impact. If you have ever worked in a middle school, you would agree there is a sense magic and contagious energy within middle school students. Middle school is often an overlooked and untapped resource when considering efforts to transform school and district culture. Middle school students start to develop passions and a voice for advocacy, making agency a powerful accelerator when students channel their collective energy towards a shared vision for change. This past year has placed tremendous pressures on our educators, school leaders, students, and parents; yet, it has also offered us a remarkable opportunity to re-imagine our educational system by focusing on a more personalized approach to learning for both our students and adults. Educators have re-entered the learner’s seat with an immediate urgency to enhance their instructional practices so they may engage students in learning and manage their classrooms in new and nontraditional learning environments. The result of this shift has yielded many benefits, such as the use of technology for learning and curation of digital curriculum resources; however, it has also created a renewed need to focus on the efficacy and professional learning of educators. Rising concerns with equity, learning loss, and mental health have added additional pressure for school leaders, teachers, and support staff. Therefore, there is a need to reimagine our vision for the future of education and strategically plan flexible pathways to make our vision a reality. A vision for embedding ongoing personalized coaching within professional learning communities can improve teacher efficacy, enhance collaborative data analysis and lesson planning, and transform school culture to maximize personalized learning for all students