Volumes of highly twisted knots and links

We show that for a large class of hyperbolic knots and links, we can determine bounds on the volume of the link complement from combinatorial information given by a link diagram. Specifically, there is a universal constant C such that if a knot or link admits a prime, twist reduced diagram with at least 2 twist regions and at least C crossings per twist region, then the link complement is hyperbolic with volume bounded below by 3.3515 times the number of twist regions in the diagram. C is at most 113.Comment: 14 pages, 4 figures. Minor changes to clarify exposition, fix typos, and correct a historical inaccuracy in the introduction. Paper has now appeared in AG

Disrupting the speech motor mechanism: exploring left hemisphere specialisation for verbal and manual sequencing using a dual task approach

It is well established that speech production and fine motor praxis are linked neurologically, with evidence indicating that shared left hemisphere networks underpin both functions. One suggestion for the crucial component of this left lateralised specialisation is that both speech and praxis rely on effective sequencing of information for their successful execution (Flowers & Hudson, 2013). Whilst the concept of speech and motor sequencing and their neural correlates is well accepted, few studies explore the behavioural characteristics of language and praxis when performed simultaneously. This study was designed to probe the mechanism behind this interaction by overloading the left hemisphere sequencing network via a dual task paradigm. Participants (n=22) performed an experimental set of motor and speech tasks, (namely a verbal fluency paradigm and an electronic peg moving task), as well as a control set of similar tasks, (namely digit recall and a box crossing tracking test), both under single and dual task conditions. The two sets of tasks differed on the extent to which they relied on motor and speech sequencing, and it was hypothesised that tasks more reliant on this type of processing (i.e. the experimental condition) would suffer a greater performance decrement under dual task conditions, thus reflecting the greater load placed on left hemisphere speech and praxis centres. Each task was performed for 2 mins for both conditions, and scores were calculated based upon number of correct responses/movements made. Ordering of single and dual presentation was counterbalanced between participants. Participants subsequently underwent functional Transcranial Doppler ultrasound (fTCD) whilst performing a word generation task, to provide a direct measure of their hemispheric language dominance. Results showed that tasks forming the experimental arm were more impaired under dual task conditions than the control tasks, suggesting they both relied on a common processing system. Most interestingly speech production scores in the experimental arm were consistently impaired under dual task conditions, whereas the control arm speech task performance remained consistent with single task conditions. Motor performance suffered less in dual task conditions over both experimental and control arms, but there was a significant effect of hand dominance on performance in dual task conditions, whereby non-preferred hand usage didn’t suffer under dual task conditions, but preferred hand did. This data indicates the common processing capacity for speech and fine motor tasks of the right hand are controlled by left hemisphere networks which can be disrupted through a dual task paradigm. This data supports theories suggesting a motor based, gestural origin for language (e.g. Corballis, 2003), and indicates that speech production is more sensitive to the effects of increased processing requirements than are motor tasks

Factors Associated With Receipt of Preventive Dental Treatment Procedures Among Adult Patients at a Dental Training School in Wisconsin, 2001-2002

Background: Gender differences in oral health-related quality of life and the fear of dental pain in seeking and receiving preventive dental care have been recognized and documented. Preventive dental treatment procedures (PDTPs) are commonly accepted as the primary approach to prevent dental disease. Objective: We examined whether the likelihood of receiving PDTPs differed by gender in adult patients receiving dental care at a dental training institution in Milwaukee, Wisconsin.Methods: Data from the Marquette University School of Dentistry electronic patient management database for 2001 through 2002 were analyzed. Descriptive, bivariate, and multivariable analyses were performed. The preventive procedures used in the study were those coded in accordance with the American Dental Association\u27s classification system: D1110 (adult prophylaxis: professional cleaning and polishing of the teeth), D1204 (adult topical application of fluoride), D1205 (adult topical application of fluoride plus prophylaxis), and D1330 (oral hygiene instruction).Results: Of the 1563 consecutive patient records (888 women, 675 men) reviewed for the years 2001-2002, 794 individuals (51%), aged 18 to 60 years, were identified as having received PDTPs. At the bivariate level, a significant gender difference in the receipt of PDTPs was identified (423 women [48%] vs 371 men [55%]; P = 0.004). In the multivariable analyses, age, race/ethnicity, marital status, poverty level, and health insurance type (public, private, none) were significantly associated with the receipt of PDTPs (all, P \u3c 0.05), but gender was not.Conclusions: Gender differences in receiving PDTPs were not found in this dental school patient population. Receipt of PDTPs was associated with other demographic factors such as age, race/ethnicity, marital status, income level, and health insurance

What cell wall components are the best indicators for Miscanthus digestibility and conversion to ethanol following variable pretreatments?

Background: Energy crops including Miscanthus provide a storable, portable energy source which can be used to complement a wide range of products and energy generation systems. Miscanthus is predominantly used in Europe as a combustion material for electricity generation but also has the potential for biochemical conversion due to its high yield and low-nutrient requirements. The ratio of holocellulose (hemicellulose and cellulose combined) to acid detergent lignin (H:L) within the senesced material has previously been shown to indicate the relative suitability of Miscanthus accessions for thermochemical conversion. In this study, the ratio was assessed to examine its use as a selection aid for biochemical conversion. 20 highly-characterised Miscanthus accessions were saccharified using an enzyme mix to determine optimum sugar release. Nine of these accessions spanning high, medium and low H:L ratios were then autoclaved with dilute acid, alkali or water, and enzymically hydrolysed and fermented to produce ethanol. Samples taken throughout the process allowed assessments of released sugars. Results: Enzymic degradation of the biomass showed a relationship between H:L ratio and glucose release, with high glucose release for high H:L ratio accessions and vice versa. Xylose release showed no such relationship. This relationship was maintained following pretreatments and enzyme saccharification, where compound analysis showed that following all pretreatments, accessions with high H:L ratios repeatedly had the highest releases of glucose, xylose and arabinose, and produced more ethanol. Release of all measured compounds increased with the pretreatment severity and ethanol yields from each pretreatment correlated with the respective glucose yield, providing assurance that any inhibitory compounds generated were tolerated by the fermentation yeast. Strong correlations were also seen between glucose release, ethanol and cell wall components, with cellulose showing the highest correlations with ethanol yields for some treatments and H:L ratio with others. Conclusions: The H:L ratio is a good predictor of ethanol yields and sugar release from Miscanthus in this study but individual components lignin and cellulose also correlate well, especially for hot water and mild acid pretreatments. In conclusion, use of the H:L ratio does not provide any advantages over the concentration of individual cell wall components for predicting sugar release and ethanol yields.publishersversionPeer reviewe

Cerebral lateralisation of speech production and motor skill

The association between praxis and language is longstanding in neuropsychology, with evidence revealing that left hemisphere lesions often lead to combined impairments in motor control and speech (Rasmussen and Milner, 1975; Goldenberg, 2013). Strong left hemisphere asymmetry for language is a robust finding at the population level (e.g. Knecht et al 2000a) and similarly the cortical activation patterns of manual praxis for skilled tasks also reveal a left hemisphere bias (Buxbaum et al, 2005; Haaland et al, 2004). As such, common neural mechanisms are thought to underlie both speech and motor skill, especially actions involving fine motor control of the hands. However, evidence for a clear causal relationship between handedness and speech laterality has proven somewhat weak and inconsistent, due to the wide variation in measurement and classification approaches used (Groen, et al, 2013). A suggestion by Flowers and Hudson (2013) is that motor and speech laterality are related where they involve a common feature of motor output, namely the co-ordination of sequences of movements or utterances to execute a plan or intention so as to achieve a goal; either limb movement or expression of an idea (e.g. Grimme, et al, 2011). The research conducted here investigates speech and motor lateralisation from the hypothesis that sequencing based tasks will be best able to elicit the predicted left hemisphere activation patterns. Five empirical chapters are presented detailing a number of studies involving healthy adults, typically developing children and adults with Developmental Coordination Disorder. The research uses an emerging technique in cognitive neuropsychology; functional Transcranial Doppler (fTCD) sonography, to explore hemispheric laterality of speech and motor skill. Measurements of the degree of activation in each of the hemispheres during language tasks, and the use of a skill-based motor task to determine handedness, are the primary indicators of lateralisation used throughout this thesis. Results from the first 3 chapters 4 reveal that 1) atypical patterns of speech laterality are linked to greater performance differences on motor skill tasks; 2) that whilst hand preference is established early on in childhood the relative performance ability between the non-preferred and preferred hands develops linearly with age; 3) adults with developmental coordination disorder display atypical patterns of laterality of speech networks. The final 2 empirical chapters employ novel neuroimaging paradigms to investigate the mechanisms underlying the links between speech and motor sequencing. Results show that the pegboard task elicits left hemisphere dominant activation regardless of the hand used, unlike other motor tasks with similar properties. Finally a dual task paradigm demonstrates that speech production suffers greater impairments than motor skill when performed simultaneously, providing support for theories proposing a gestural origin to speech. The data are discussed in terms of the specialisation of the left hemisphere for higher order sequential processing, in the context of a lateralised speech-praxis centre model

The role of the dominant versus the non-dominant hemisphere: an fMRI study of Aphasia recovery following stroke

Background: Speech production is one of the most frequently affected cognitive functions following stroke; however, the neural mechanisms underlying the recovery of speech function are still incompletely understood. Aims: The current study aims to address the differential contributions of the dominant and non-dominant hemispheres in recovery from aphasia following stroke by comparing data from four stroke patients and 12 control participants to assess the patterns of activation during speech production tasks during functional magnetic resonance imaging (fMRI) scanning. Methods & Procedures: Four chronic stroke patients (three left-hemisphere lesion and one right-hemisphere lesion) diagnosed with Broca’s aphasia at the acute phase, but now recovered to near normal speech ability, were tested on speech production tasks (phonemic fluency, categorical fluency and picture naming) whilst undergoing fMRI. These patients were compared with 12 healthy controls undergoing the same procedure. Outcomes & Results: Individual subject analysis showed activation peaks in perilesional areas in three out of four patients. This included one patient with right-hemisphere lesion, who also showed predominant perilesional activation. Group analysis of control participants showed predominately left-hemisphere activation, but not exclusively so. Laterality indexes were calculated and showed predominant left-hemisphere lateralisation in the control group (LI = 0.4). Three out of the four patients showed speech lateralised to the same hemisphere as their lesion and the fourth patient showed speech lateralised to the opposite hemisphere to their lesion. Different speech production tasks resulted in varying lateralisation indices (LIs) within participants. Conclusions: The data suggest that perilesional areas support recovery of speech in the chronic phase post-stroke regardless of the site of the lesion. The study has implications for the understanding of functional recovery as well as for the paradigms used in fMRI to localise speech production areas. Specifically, a variety of speech tasks are required to elicit activation that is representative of the range of cortical involvement in speech in healthy adults and that also allows for accurate reporting of the extent of recovery experienced in patients

Genome scan detection of selective sweeps among biotypes of the soybean aphid, Aphis glycines, with differing virulence to resistance to A. glycines (Rag) traits in soybean, Glycine max

Multiple biotypes of soybean aphid, Aphis glycines, occur in North America adapted for survival (virulence) on soybean, Glycine max, with one or more different resistance to A. glycines (Rag) traits. The degree of genome-wide variance between biotypes and the basis of virulence remains unknown, but the latter is hypothesized to involve secreted effector proteins. Between 167,249 and 217,750 single nucleotide polymorphisms (SNPs) were predicted from whole genome re-sequencing of A. glycines avirulent biotype 1 (B1) and virulent B2, B3 and B4 colony-derived iso-female lines when compared to the draft B1 genome assembly, Ag_bt1_v6.0. Differences in nucleotide diversity indices (π) estimated within 1000 bp sliding windows demonstrated that 226 of 353 (64.0%) regions most differentiated between B1 and ≥ 2 virulent biotypes, representing \u3c 0.1% of the 308 Mb assembled genome size, are located on 15 unordered scaffolds. Furthermore, these 226 intervals were coincident and show a significant association with 326 of 508 SNPs with significant locus-by-locus FST estimates between biotype populations (r = 0.6271; F1,70 = 45.36, P \u3c 0.001) and genes showing evidence of directions selection (πN/πS \u3e 2.0; r = 0.6233; F1,70 = 50.20, P \u3c 0.001). A putative secreted effector glycoprotein is encoded in proximity to genome intervals of low estimated π (putative selective sweep) within avirulent B1 compared to all three virulent biotypes. Additionally, SNPs are clustered in or in proximity to genes putatively involved in intracellular protein cargo transport and the regulation of secretion. Results of this study indicate that factors on a small number of scaffolds of the A. glycines genome may contribute to variance in virulence towards Rag traits in G. max

Development of a Modified Cervical Collar to Eliminate Overheating and Dysphagia Side Effects

Currently, thousands of people each year require the use of a rigid cervical collar. The collars are used in situations of emergency, as well as in situations of precaution, when spinal injury is or may be present. There are many different styles and sizes of cervical collars available on the market today; however, common side effects are noticed when wearing the collars that may reduce the effectiveness to the patient. Often patients complain of general discomfort issues or may suffer from more serious side effects such as pressure sores, increased intracranial pressure, dysphagia, and abnormal distraction within the upper spine. A need exists for the modification of current cervical collars to reduce the painful or uncomfortable side effects associated with wearing them which would, in turn, increase the effectiveness of the therapy that the collar provides to the spine. There are two main components of most cervical collar designs: the rigid outer shell and the inner padding. Both of these components have been considered by our design team in the modification design to improve the efficacy of the cervical collar and to reduce side effects from wearing them. The main goals of this project were to reduce the overall discomfort patients experience that is associated with overheating and dysphagia side effects. As a team, we have researched and tested many materials to determine the best fit for our modified cervical collar. The tests included an end user survey that determined the overall comfortability between the available collars, a cold temperature retention test that showed how long the prospective cooling materials would maintain lower temperatures, and an in-collar temperature test that looked at the temperatures of the materials within the lining of a collar As a team, we have designed a rigid cervical collar that utilizes a slightly flexible, but durable 1/16th inch polyethylene outer shell with padded gel inserts. The outer shell is a two piece design that incorporates the favorable concepts of currently manufactured collars. The two pieces were cut using a scroll saw and molded using an application of heat to the desired positions. There are multiple cut outs in the plastic of both pieces that give flexibility when fitting the collar and the pieces can be connected using velcro straps. The inner “cooling system” is composed of two hydrogels: TheraPearl Technology freezable beads and a pressure activated cooling pad marketed by The Green Pet Shop. The cooling materials will then be wrapped together in polyolefin shrink wrap and placed within specified cutout positions in the antimicrobial padding. Finally the components will be covered in a heat resistant cloth material to ensure direct contact with the skin is compatible and comfortable for the patient. The modifications focus on reducing the hot spots on the cheeks, chin, and neck that are commonly associated with discomfort in patients, will address the discomfort of the chin and neck associated with dysphagia, and will also maintain the rigidity and restriction of motion necessary of the collar. Testing on the efficacy of the design concepts brought forth is still in progress, but we believe the modified cervical collar can increase patient comfort levels and reduce overheating

The relationship between lateralization patterns from sequence based motor tasks and hemispheric speech dominance

Objective: Skilled motor praxis and speech production display marked asymmetries at the individual and the population level, favouring the right hand and the left hemisphere respectively. Theories suggesting a common processing mechanism between praxis and speech are supported by evidence that shared neural architecture underlies both functions. Despite advances in understanding the neurobiology of this left-hemisphere specialisation the cortical networks linking these two functions are rarely investigated on a behavioural level. Method: This study deploys functional Transcranial Doppler (fTCD) ultrasound to directly measure hemispheric activation during skilled manual praxis tasks shown to be correlated to hemispheric speech lateralisation indices. In a new paradigm we test the hypothesis that praxis tasks are highly dependent on the left hemisphere's capacity for processing sequential information will be better correlated with direction and strength of hemispheric speech lateralisation Results: Across two experiments we firstly show that only certain praxis tasks (pegboard and coin-rotation) correlated with direct measurements of speech lateralisation despite shared properties across all tasks tested. Secondly, through novel imaging of hemispheric activation during praxis, results showed that the pegboard differed in the lateralisation pattern created and furthermore that it was significantly related to speech laterality indices, which was not the case for either of the other two tasks. Conclusion: These results are discussed in terms of a lateralised speech-praxis control mechanism and demonstrates that measurements of motor paradigms through the use of fTCD are reliable enough to provide a new insight to the behavioural relationship been speech and handedness

Testing the relationship between lateralization on sequence-based motor tasks and language laterality using an online battery

Studies have highlighted an association between motor laterality and speech production laterality. It is thought that common demands for sequential processing may underlie this association. However, most studies in this area have relied on relatively small samples and have infrequently explored the reliability of the tools used to assess lateralization. We, therefore, established the validity and reliability of an online battery measuring sequence-based motor laterality and language laterality before exploring the associations between laterality indices on language and motor tasks. The online battery was completed by 621 participants, 52 of whom returned to complete the battery a second time. The three motor tasks included in the battery showed good between-session reliability (r ≥ .78) and were lateralized in concordance with hand preference. The novel measure of speech production laterality was left lateralized at population level as predicted, but reliability was less satisfactory (r = .62). We found no evidence of an association between sequence-based motor laterality and language laterality. Those with a left-hand preference were more strongly lateralized on motor tasks requiring midline crossing; this effect was not observed in right-handers. We conclude that there is little evidence of the co-lateralization of language and sequence-based motor skill on this battery