19Stable isotope analysis has emerged as one of the primary means for examining the structure and 20 dynamics of food webs, and numerous analytical approaches are now commonly used in the 21 field. Techniques range from simple, qualitative inferences based on the isotopic niche, to 22Bayesian mixing models that can be used to characterize food-web structure at multiple 23 hierarchical levels. We provide a comprehensive review of these techniques, and thus a single 24 reference source to help identify the most useful approaches to apply to a given data set. We

Striatal atrophy begins many years prior to diagnosable HD, and assessment of atrophy on MRI may be very useful in both predicting HD onset and in tracking progression in future therapeutic trials in preclinical subjects.

No abstract

We recently described a disorder termed Huntington disease-like 2 (HDL2) that completely segregates with an unidentified CAG/CTG expansion in a large pedigree (W). We now report the cloning of this expansion and its localization to a variably spliced exon of JPH3 (encoding junctophilin-3), a gene involved in the formation of junctional membrane structures.

Inherent site factors can generate substantial variation in the ground water nitrate removal capacity of riparian zones. This paper examines research in the glaciated Northeast to relate variability in ground water nitrate removal to site attributes depicted in readily available spatial databases, such as SSUIRGO. Linking site‐specific studies of riparian ground water nitrate removal to spatial data can help target high‐value riparian locations for restoration or protection and improve the modeling of watershed nitrogen flux. Site attributes, such as hydric soil status (soil wetness) and geomorphology, affect the interaction of nitrate‐enriched ground water with portions of the soil ecosystem possessing elevated biogeochemical transformation rates (i.e., biologically active zones). At our riparian sites, high ground water nitrate‐N removal rates were restricted to hydric soils. Geomorphology provided insights into ground water flowpaths. Riparian sites located on outwash and organic/alluvial deposits have high potential for nitrate‐enriched ground water to interact with biologically active zones. In till deposits, ground water nitrate removal capacity may be limited by the high occurrence of surface seeps that markedly reduce the time available for biological transformations to occur within the riparian zone. To fully realize the value of riparian zones for nitrate retention, landscape controls of riparian nitrate removal in different climatic and physiographic regions must be determined and translated into available spatial databases.

Dementia and psychiatric disorders are common in AL and have suboptimal rates of recognition and treatment. This may contribute to morbidity and interfere with the ability of residents to age in place.

Huntington disease (HD) is a neurodegenerative disorder caused by the abnormal expansion of CAG repeats in the HD gene on chromosome 4p16.3. Past studies have shown that the size of expanded CAG repeat is inversely associated with age at onset (AO) of HD. It is not known whether the normal Huntington allele size influences the relation between the expanded repeat and AO of HD. Data collected from two independent cohorts were used to test the hypothesis that the unexpanded CAG repeat interacts with the expanded CAG repeat to influence AO of HD. In the New England Huntington Disease Center Without Walls (NEHD) cohort of 221 HD affected persons and in the HD-MAPS cohort of 533 HD affected persons, we found evidence supporting an interaction between the expanded and unexpanded CAG repeat sizes which influences AO of HD (P = 0.08 and 0.07, respectively). The association was statistically significant when both cohorts were combined (P = 0.012). The estimated heritability of the AO residual was 0.56 after adjustment for normal and expanded repeats and their interaction. An analysis of tertiles of repeats sizes revealed that the effect of the normal allele is seen among persons with large HD repeat sizes (47-83). These findings suggest that an increase in the size of the normal repeat may mitigate the expression of the disease among HD affected persons with large expanded CAG repeats.

Neuropathologic and neuroimaging studies have suggested that frontal lobes are affected in Huntington's disease (HD), and that atrophy in this region may be associated with some of the cognitive impairment and clinical decline observed in patients with HD. We measured gray and white matter volumes within the frontal lobes on MRI for 20 patients with HD (10 mildly affected and 10 moderately affected) and 20 age- and sex-matched control subjects. We also correlated frontal lobe measurements with measures of symptom severity and cognitive function. Patients who were mildly affected had frontal lobe volumes (both gray and white matter) essentially identical to those of control subjects, despite clearly abnormal basal ganglia. Patients who were moderately affected demonstrated significant reductions in total frontal lobe volume (17%) and frontal white matter volume (28%). Frontal lobe white matter volume reductions, but not total frontal lobe volume reductions, were disproportionately greater than overall brain volume reductions (17%). Frontal lobe volume correlated with symptom severity and general cognitive function, but these correlations did not remain significant after taking into account total brain volume. We conclude that cognitive impairment and symptom severity are associated with frontal lobe atrophy, but this association is not specific to the frontal lobes. Frontal lobe atrophy (like total brain atrophy) occurs in later stages of increasing HD symptom severity and this atrophy primarily involves white matter.