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Generalized Baumslag-Solitar groups are a class of combinatorially interesting groups. Their group theory is also closely associated to a the topology of a class of 2-dimensional spaces. These 2-dimensional spaces are Seifert fibred. We develop the basic topology of these fibrations and derive some of the most immediate group theoretic consequences of this topology.
This survey article has two components. The first part gives a gentle introduction to Serres notion of $G$-complete reducibility, where $G$ is a connected reductive algebraic group defined over an algebraically closed field. The second part concerns consequences of this theory when $G$ is simple of exceptional type, specifically its role in elucidating the subgroup structure of $G$. The latter subject has a history going back about sixty years. We give an overview of what is known, up to the present day. We also take the opportunity to offer several corrections to the literature.
Every four years leading researchers gather to survey the latest developments in all aspects of group theory. Since 1981, the proceedings of these meetings have provided a regular snapshot of the state of the art in group theory and helped to shape the direction of research in the field. This volume contains selected papers from the 2022 meeting held in Newcastle. It includes substantial survey articles from the invited speakers, namely the mini course presenters Michel Brion, Fanny Kassel and Pham Huu Tiep; and the invited one-hour speakers Bettina Eick, Scott Harper and Simon Smith. It features these alongside contributed survey articles, including some new results, to provide an outstanding resource for graduate students and researchers.
To determine whether gross motor scores of toddlers after complex cardiac surgery were different from fine motor scores and were adequately represented by motor composite scores and, whether acute care predictors and chronic childhood health markers of gross motor scores differed from those of fine motor.
Methods:
This prospective inception-cohort outcomes study included 171 toddlers after complex cardiac surgery with cardiopulmonary bypass at age <6 months, born in Northern Alberta from 2009 to 2019, and without known chromosomal abnormalities. At a mean (standard deviation) age of 21.7 (3.7) months, the Bayley Scales of Infant and Toddler Development-III determined motor composite and scaled scores (normative values, 100 (15), 10 (3), respectively). The same variables from surgery and assessment were analysed using multivariate regression to predict gross and fine motor scores; results expressed as effect size (95% confidence interval) with % variance.
Results:
Composite, fine, and gross motor scores were 89.7 (14.2), 9.4 (2.5), and 7.2 (2.7), respectively. Predictive variables accounted for 21.2% of the variance for fine motor, and 36.9% for gross motor. Multivariate analysis for gross motor scores included toddlers need for cardiac medication, effect size (95% confidence interval) −0.801 (−1.62, −0.02), gastrostomy, −1.35 (−2.39, −0.319), and single ventricle, −0.93 (−1.71, −0.15). These same variables did not predict fine motor scores.
Conclusion:
Gross motor skills commonly were lower than fine motor skills for toddlers after complex cardiac surgery. Predictors for gross motor scores differed from fine motor scores. Separate reporting of gross motor scores could lead to improved identification of predictors of delay and to optimised early intervention.
To determine the association between blood markers of white matter injury (e.g., serum neurofilament light and phosphorylated neurofilament heavy) and a novel neuroimaging technique measuring microstructural white matter changes (e.g., diffusion kurtosis imaging) in regions (e.g., anterior thalamic radiation and uncinate fasciculus) known to be impacted in traumatic brain injury (TBI) and associated with symptoms common in those with chronic TBI (e.g., sleep disruption, cognitive and emotional disinhibition) in a heterogeneous sample of Veterans and non-Veterans with a history of remote TBI (i.e., >6 months).
Participants and Methods:
Participants with complete imaging and blood data (N=24) were sampled from a larger multisite study of chronic mild-moderate TBI. Participants ranged in age from young to middle-aged (mean age = 34.17, SD age = 10.96, range = 19-58) and primarily male (66.7%). The number of distinct TBIs ranged from 1-5 and the time since most recent TBI ranged from 0-30 years. Scores on a cognitive screener (MoCA) ranged from 22-30 (mean = 26.75). We performed bivariate correlations with mean kurtosis (MK) in the anterior thalamic radiation (ATR; left, right) uncinate fasciculus (UF; left, right), and serum neurofilament light (NFL), and phosphorylated neurofilament heavy (pNFH). Both were log transformed for non-normality. Significance threshold was set at p<0.05.
Results:
pNFH was significantly and negatively correlated to MK in the right (r=-0.446) and left (r=-0.599) UF and right (r=-0.531) and left (r=-0.469) ATR. NFL showed moderate associations with MK in the right (r=-0.345) and left (r=-0.361) UF and little to small association in the right (r=-0.063) and left (r=-0.215) ATR. In post-hoc analyses, MK in both the left (r=0.434) and right (r=0.514) UF was positively associated with performance on a frontally-mediated list-learning task (California Verbal Learning Test, 2nd Edition; Trials 1-5 total).
Conclusions:
Results suggest that serum pNFH may be a more sensitive blood marker of microstructural complexity in white matter regions frequently impacted by TBI in a chronic mild-moderate TBI sample. Further, it suggests that even years after a mild-moderate TBI, levels of pNFH may be informative regarding white matter integrity in regions related to executive functioning and emotional disinhibition, both of which are common presenting problems when these patients are seen in a clinical setting.
Unproven economic returns at the farm level are a major barrier to large-scale adoption of cover crops. The objective of this study was to evaluate the short-run private net returns to producers implementing a cereal rye (Secale cereale L.) cover crop preceding the no-till corn (Zea mays L.) phase of a US Midwest corn–soybean (Glycine max [L.] Merr.) rotation in an integrated crop and cow–calf operation. We used experimental agronomic data from six location-years in Iowa to estimate private net returns to cereal rye across alternative scenarios in a partial budget framework. Net returns in the absence of grazing averaged −$123.74 ha−1 and were negative for 82.2% of the treatments, while net returns under partial grazing averaged −$15.24 ha−1 and were negative for 54.8% of the treatments. Early-broadcast cereal rye produced higher biomass and larger net cost savings in the livestock enterprise than late-drilled cereal rye, but it also resulted in higher corn yield penalties. In the no-grazing scenario, net losses for early-broadcast cereal rye were $165.97 ha−1 larger, on average, than for late-drilled cereal rye. Our findings should raise awareness about the low probability of obtaining positive annual private net returns to cereal rye in Iowa in the absence of sizable targeted financial incentives, and inform the policy discussion on the cost-effectiveness of government-sponsored conservation programs.
Close-range sensors are employed to observe glaciological processes that operate over short timescales (e.g. iceberg calving, glacial lake outburst floods, diurnal surface melting). However, under poor weather conditions optical instruments fail while the operation of radar systems below 17 GHz do not have sufficient angular resolution to map glacier surfaces in detail. This letter reviews the potential of millimetre-wave radar at 94 GHz to obtain high-resolution 3-D measurements of glaciers under most weather conditions. We discuss the theory of 94 GHz radar for glaciology studies, demonstrate its potential to map a glacier calving front and summarise future research priorities.
To determine potentially modifiable risk factors for a complicated Glenn procedure (cGP) and whether a cGP predicted adverse neurodevelopmental and functional outcomes. A cGP was defined as post-operative death, heart transplant, extracorporeal life support, Glenn takedown, or prolonged ventilation.
Methods:
All 169 patients having a Glenn procedure from 2012 to 2017 were included. Neurodevelopmental assessments were performed at age 2 years in consenting survivors (n = 156/159 survivors). The Bayley Scales of Infant and Toddler Development-3rd Edition (Bayley-III) and the Adaptive Behavior Assessment System-2nd Edition (ABAS-II) were administered. Adaptive functional outcomes were determined by the General Adaptive Composite (GAC) score from the ABAS-II. Predictors of outcomes were determined using univariate and multiple variable linear or Cox regressions.
Results:
Of patients who had a Glenn procedure, 10/169 (6%) died by 2 years of age and 27/169 (16%) had a cGP. Variables statistically significantly associated with a cGP were the inotrope score on post-operative day 1 (HR 1.04, 95%CI 1.01, 1.06; p = 0.010) and use of inhaled nitric oxide post-operatively (HR 7.31, 95%CI 3.19, 16.76; p < 0.001). A cGP was independently statistically significantly associated with adverse Bayley-III Cognitive (ES −10.60, 95%CI −17.09, −4.11; p = 0.002) and Language (ES −11.43, 95%CI −19.25, −3.60; p = 0.004) scores and adverse GAC score (ES −14.89, 95%CI −22.86, −6.92; p < 0.001).
Conclusions:
Higher inotrope score and inhaled nitric oxide used post-operatively were associated with a cGP. A cGP was independently associated with adverse 2-year neurodevelopmental and functional outcomes. Whether early recognition and intervention for risk of a cGP can prevent adverse outcomes warrants study.
Background: Mutations in the slow skeletal muscle troponin T (TNNT1) gene cause a congenital nemaline myopathy resulting in death from respiratory insufficiency in early infancy. We report on four French Canadians with a novel congenital TNNT1 myopathy. Methods: Patients underwent lower extremity and paraspinal MRI, quadriceps biopsy and genetic testing. TNNT1 expression in muscle was assessed by quantitative PCR and immunoblotting. Wild type or mutated TNNT1 mRNAs were co-injected with morpholinos in a zebrafish knockdown model to assess for rescue of the morphant phenotype. Results: Four patients shared a novel missense homozygous mutation in TNNT1. They developed from childhood slowly progressive limb-girdle weakness with spinal rigidity and contractures. They suffered from restrictive lung disease and recurrent episodes of rhabdomyolysis. Older patients remained ambulatory into their sixties. Lower extremity MRI showed symmetrical myopathic changes. Paraspinal MRI showed diffuse fibro-fatty involution. Biopsies showed multi-minicores. Nemaline rods were seen in half the patients. TNNT1 mRNA expression was similar in controls and patients, while levels of TNNT1 protein were reduced in patients. Wild type TNNT1 mRNA rescued the zebrafish morphants but mutant transcripts failed to do so. Conclusions: This study expands the spectrum of TNNT1-related myopathy to include a milder clinical phenotype caused by a functionally-confirmed novel mutation.
Background: Mutations in the slow skeletal muscle troponin T (TNNT1) gene cause a congenital nemaline myopathy resulting in death from respiratory insufficiency in early infancy. We report on four French Canadians with a novel congenital TNNT1 myopathy. Methods: Patients underwent lower extremity and paraspinal MRI, quadriceps biopsy and genetic testing. TNNT1 expression in muscle was assessed by quantitative PCR and immunoblotting. Wild type or mutated TNNT1 mRNAs were co-injected with morpholinos in a zebrafish knockdown model to assess for rescue of the morphant phenotype. Results: Four patients shared a novel missense homozygous mutation in TNNT1. They developed from childhood slowly progressive limb-girdle weakness with spinal rigidity and contractures. They suffered from restrictive lung disease and recurrent episodes of rhabdomyolysis. Older patients remained ambulatory into their sixties. Lower extremity MRI showed symmetrical myopathic changes. Paraspinal MRI showed diffuse fibro-fatty involution. Biopsies showed multi-minicores. Nemaline rods were seen in half the patients. TNNT1 mRNA expression was similar in controls and patients, while levels of TNNT1 protein were reduced in patients. Wild type TNNT1 mRNA rescued the zebrafish morphants but mutant transcripts failed to do so. Conclusions: This study expands the spectrum of TNNT1-related myopathy to include a milder clinical phenotype caused by a functionally-confirmed novel mutation.
Background: Neonatal Arterial Ischemic Stroke (NAIS) is a common form of paediatric stroke often affecting classical language areas. The post-stroke reorganization of functional language networks may provide insight into later-emerging language deficits and may help to identify at-risk children with NAIS. Methods: A cross-sectional study of fourteen children with left (n=8; 2M; 11.1±2.2 years) or right (n=6; 3M; 12.4±4 years) middle cerebral artery (MCA) NAIS, as well as seven neurotypical children (5M; 13.4±2.7 years), was conducted. Children listened to correct/incorrect syntactic sentences while MEG was recorded, and task-related functional connectivity in the time window and frequency band of interest was determined. Language outcomes were assessed using a battery of neuropsychological tests. Results: A network-based analysis of syntactic language processing (4-7 Hz, 1.2-1.4s) revealed a dysfunctional bilateral frontal-temporal network involving language areas in patients (p=0.01). Patients with right-MCA stroke exhibited a positive correlation between left hemispheric connectivity and measures of language skill (p<0.01), resembling the neurotypical children. In left-MCA stroke patients, greater bilateral connectivity or right laterality in the language network is correlated with good outcome (p<0.05). Conclusions: Depending on the hemispheric location of stroke, certain patterns of language network reorganization may account for impairments in a bilateral frontal-temporal language subnetwork and support language outcome.
Outdoor advertisements for food and drink products form a large part of the food environment and they disproportionately promote unhealthy products. However, less is known about the social patterning of such advertisements. The main aim of this study was to explore the socio-economic patterning of food and drink advertising at bus stops in Scotland’s capital city, Edinburgh.
Design:
Bus stop advertisements were audited to identify food/drink adverts and classify them by food/drink category (i.e. ‘advert category’). This data were then linked to area-based deprivation and proximity measures. Neighbourhood deprivation was measured using the bus stop x/y co-ordinates, which were converted to postcodes to identify the matching 2012 deprivation level via the Scottish Index of Multiple Deprivation. Distance to schools and leisure centres were also collected using location data. Generalised estimating equations and linear regression analyses were used to assess associations between the promotion of advert categories and deprivation and proximity to schools/leisure centres, respectively.
Setting:
Edinburgh city, United Kingdom.
Results:
561 food/drink advertisements were identified across 349 bus stops, with 8 advertisement categories noted and included in the final analysis, including alcohol, fast food outlets and confectionary. The majority of adverts were for ‘unhealthy’ food and drink categories, however there was no evidence for any socio-economic patterning of these advertisements. There was no evidence of a relationship between advertisements and proximity to schools and leisure centres.
Conclusions:
While there is no evidence for food and drink advertising being patterned by neighbourhood deprivation, the scale of unhealthy advertising is an area for policy evaluations and interventions on the control of such outdoor advertising.