Quantitative shape analysis of soil map delineations in Benton County, Oregon

Soils are 3-dimensional bodies that make up natural landscapes. In addition to the morphological properties used to characterize soils, soil bodies also have the properties of size and shape. Soil maps are made in an effort to provide information on the spatial distribution of different kinds of soils. Soil mappers draw to scale, as accurately as possible, the sizes and shapes of the different kinds of soil bodies they observe in the landscape. Beyond that, however, very little quantitative information relative to size and shape is provided to soil map users. Quantitative shape characterization presents several opportunities to learn about soil genesis and soil interpretations for land use. Intriguing questions include "Why does a soil body have the particular shape it has?", "Does each map unit possess an intrinsic shape or range of shapes?", "Do existing map unit interpretations apply equally to delineations of different size and shape?", "How can shape data for individual delineations be aggregated into an overall description of soil patterns in different geographic areas?", "What effects do soil patterns have on land use?". None of these questions can be answered without first having an appropriate technique for characterizing the shapes of individual delineations. The objective of this research, therefore, was to examine several possible shape indexes and isolate those few which had the greatest utility for characterizing shape. These few were then used to examine shape distributions within a few selected map units and compare shapes between map units. Data were collected by digitizing 452 delineations sampled from 13 different kinds of soil bodies identified in the soil survey of Benton County. For each delineation, 43 potential indexes were calculated. These included primary measurements, such as area and perimeter, and figure attribute ratios such as Horton's form ratio, Miller's circularity index, Schumm's elongation ratio, and Fridland's coefficient of dissection. A convex hull was circumscribed around each delineation, and the same primary measurements and attribute ratios were calculated for the convex hull. Additional indexes were calculated by comparing values determined for a delineation and corresponding values for it's convex hull. One additional technique used was to fit each polygon and convex hull with a 22-sided vertex lag polygon. Calculation of distances between vertices of this polygon leads to the derivation of a vertex lag index of shape. Variations on the vertex lag theme provided several additional indexes. Correlation analysis showed that the set of 43 indexes was highly intercorrelated. In order to reduce this set to a smaller set of minimally correlated indexes, the entire data set was subjected to a factor analysis. The result was a set of three dominant factors, which together accounted for 86.1% of the total variance in the data set. Each factor was interpreted by considering the nature of the shape indexes that loaded heavily on it, and a single index was selected to represent each factor on the basis of maximum interpretability. The first factor was interpreted as a measure of the complexity, or irregularity, of a delineation. The vertex lag index for the delineation was selected as the best single index to represent this attribute of shape. The second factor included all of the primary measurements. Though not a measure of shape per se, primary measurement data were viewed as significant elements in the spatial description of soil map delineations. Polygon area was taken as the best index to represent the effects of primary measurements. The third factor was interpreted as a measure of form. In this case, Schumm's elongation ratio, as measured on the convex hull, was found to be the most interpretable index of form. These three attributes, size, form, and complexity, provided the best quantitative description of shape. The indexes that represent them were found to be minimally correlated and maximally interpretable. Each of the 13 kinds of soil bodies sampled was characterized in terms of the three aspects of shape using descriptive statistics and frequency histograms. Comparisons between samples were evaluated using the Mann-Whitney U test. The data suggested that delineations belonging to a single soil mapping unit do have distinctive distributions of size, form, and complexity. Shape differences between mapping units were most evident when comparing soils on different landforms, parent materials, and slope gradients

Climate drives the geography of marine consumption by changing predator communities

Este artículo contiene 7 páginas, 3 figuras, 1 tabla.The global distribution of primary production and consumption by humans (fisheries) is well-documented, but we have no map linking the central ecological process of consumption within food webs to temperature and other ecological drivers. Using standardized assays that span 105° of latitude on four continents, we show that rates of bait consumption by generalist predators in shallow marine ecosystems are tightly linked to both temperature and the composition of consumer assemblages. Unexpectedly, rates of consumption peaked at midlatitudes (25 to 35°) in both Northern and Southern Hemispheres across both seagrass and unvegetated sediment habitats. This pattern contrasts with terrestrial systems, where biotic interactions reportedly weaken away from the equator, but it parallels an emerging pattern of a subtropical peak in marine biodiversity. The higher consumption at midlatitudes was closely related to the type of consumers present, which explained rates of consumption better than consumer density, biomass, species diversity, or habitat. Indeed, the apparent effect of temperature on consumption was mostly driven by temperature-associated turnover in consumer community composition. Our findings reinforce the key influence of climate warming on altered species composition and highlight its implications for the functioning of Earth’s ecosystems.We acknowledge funding from the Smithsonian Institution and the Tula Foundation.Peer reviewe

Case Reports1. A Late Presentation of Loeys-Dietz Syndrome: Beware of TGFβ Receptor Mutations in Benign Joint Hypermobility

Background: Thoracic aortic aneurysms (TAA) and dissections are not uncommon causes of sudden death in young adults. Loeys-Dietz syndrome (LDS) is a rare, recently described, autosomal dominant, connective tissue disease characterized by aggressive arterial aneurysms, resulting from mutations in the transforming growth factor beta (TGFβ) receptor genes TGFBR1 and TGFBR2. Mean age at death is 26.1 years, most often due to aortic dissection. We report an unusually late presentation of LDS, diagnosed following elective surgery in a female with a long history of joint hypermobility. Methods: A 51-year-old Caucasian lady complained of chest pain and headache following a dural leak from spinal anaesthesia for an elective ankle arthroscopy. CT scan and echocardiography demonstrated a dilated aortic root and significant aortic regurgitation. MRA demonstrated aortic tortuosity, an infrarenal aortic aneurysm and aneurysms in the left renal and right internal mammary arteries. She underwent aortic root repair and aortic valve replacement. She had a background of long-standing joint pains secondary to hypermobility, easy bruising, unusual fracture susceptibility and mild bronchiectasis. She had one healthy child age 32, after which she suffered a uterine prolapse. Examination revealed mild Marfanoid features. Uvula, skin and ophthalmological examination was normal. Results: Fibrillin-1 testing for Marfan syndrome (MFS) was negative. Detection of a c.1270G > C (p.Gly424Arg) TGFBR2 mutation confirmed the diagnosis of LDS. Losartan was started for vascular protection. Conclusions: LDS is a severe inherited vasculopathy that usually presents in childhood. It is characterized by aortic root dilatation and ascending aneurysms. There is a higher risk of aortic dissection compared with MFS. Clinical features overlap with MFS and Ehlers Danlos syndrome Type IV, but differentiating dysmorphogenic features include ocular hypertelorism, bifid uvula and cleft palate. Echocardiography and MRA or CT scanning from head to pelvis is recommended to establish the extent of vascular involvement. Management involves early surgical intervention, including early valve-sparing aortic root replacement, genetic counselling and close monitoring in pregnancy. Despite being caused by loss of function mutations in either TGFβ receptor, paradoxical activation of TGFβ signalling is seen, suggesting that TGFβ antagonism may confer disease modifying effects similar to those observed in MFS. TGFβ antagonism can be achieved with angiotensin antagonists, such as Losartan, which is able to delay aortic aneurysm development in preclinical models and in patients with MFS. Our case emphasizes the importance of timely recognition of vasculopathy syndromes in patients with hypermobility and the need for early surgical intervention. It also highlights their heterogeneity and the potential for late presentation. Disclosures: The authors have declared no conflicts of interes

Multivariate analysis of 1.5 million people identifies genetic associations with traits related to self-regulation and addiction.

Behaviors and disorders related to self-regulation, such as substance use, antisocial behavior and attention-deficit/hyperactivity disorder, are collectively referred to as externalizing and have shared genetic liability. We applied a multivariate approach that leverages genetic correlations among externalizing traits for genome-wide association analyses. By pooling data from ~1.5 million people, our approach is statistically more powerful than single-trait analyses and identifies more than 500 genetic loci. The loci were enriched for genes expressed in the brain and related to nervous system development. A polygenic score constructed from our results predicts a range of behavioral and medical outcomes that were not part of genome-wide analyses, including traits that until now lacked well-performing polygenic scores, such as opioid use disorder, suicide, HIV infections, criminal convictions and unemployment. Our findings are consistent with the idea that persistent difficulties in self-regulation can be conceptualized as a neurodevelopmental trait with complex and far-reaching social and health correlates

Climate drives the geography of marine consumption by changing predator communities

The global distribution of primary production and consumption by humans (fisheries) is well-documented, but we have no map linking the central ecological process of consumption within food webs to temperature and other ecological drivers. Using standardized assays that span 105° of latitude on four continents, we show that rates of bait consumption by generalist predators in shallow marine ecosystems are tightly linked to both temperature and the composition of consumer assemblages. Unexpectedly, rates of consumption peaked at midlatitudes (25 to 35°) in both Northern and Southern Hemispheres across both seagrass and unvegetated sediment habitats. This pattern contrasts with terrestrial systems, where biotic interactions reportedly weaken away from the equator, but it parallels an emerging pattern of a subtropical peak in marine biodiversity. The higher consumption at midlatitudes was closely related to the type of consumers present, which explained rates of consumption better than consumer density, biomass, species diversity, or habitat. Indeed, the apparent effect of temperature on consumption was mostly driven by temperature-associated turnover in consumer community composition. Our findings reinforce the key influence of climate warming on altered species composition and highlight its implications for the functioning of Earth's ecosystems