4,499 research outputs found
Modeling large scale species abundance with latent spatial processes
Modeling species abundance patterns using local environmental features is an
important, current problem in ecology. The Cape Floristic Region (CFR) in South
Africa is a global hot spot of diversity and endemism, and provides a rich
class of species abundance data for such modeling. Here, we propose a
multi-stage Bayesian hierarchical model for explaining species abundance over
this region. Our model is specified at areal level, where the CFR is divided
into roughly one minute grid cells; species abundance is observed at
some locations within some cells. The abundance values are ordinally
categorized. Environmental and soil-type factors, likely to influence the
abundance pattern, are included in the model. We formulate the empirical
abundance pattern as a degraded version of the potential pattern, with the
degradation effect accomplished in two stages. First, we adjust for land use
transformation and then we adjust for measurement error, hence
misclassification error, to yield the observed abundance classifications. An
important point in this analysis is that only of the grid cells have been
sampled and that, for sampled grid cells, the number of sampled locations
ranges from one to more than one hundred. Still, we are able to develop
potential and transformed abundance surfaces over the entire region. In the
hierarchical framework, categorical abundance classifications are induced by
continuous latent surfaces. The degradation model above is built on the latent
scale. On this scale, an areal level spatial regression model was used for
modeling the dependence of species abundance on the environmental factors.Comment: Published in at http://dx.doi.org/10.1214/10-AOAS335 the Annals of
Applied Statistics (http://www.imstat.org/aoas/) by the Institute of
Mathematical Statistics (http://www.imstat.org
Deamination and related reactions of some bicyclo-octylamines
The bicyclo-octylamines (1-5) have been deaminated by the nitrous acid method and by the decomposition of their nitrosocarbamates in ethanol. In addition, the amines (1-4) were deaminated by the decomposition of their triazenes in acetic acid. Complete quantitative analyses of the products
[diagrams displayed]
from the nitrosocarbamate decompositions were obtained using analytical capillary column g.l.c. techniques developed by Banks1. Incomplete information was obtained from the nitrous acid and triazene decompositions.
The results from (1) and (2) were very different from the solvolysis products of the corresponding tosylates reported earlier by Banks1 but broadly in agreement with the results from cis- and trans-4-t-butylcyclohexylamines.
The endo-amine (1) gave large amounts of elimination and hydride shift products. At the unrearranged position, internal substitution to give R-X (Scheme) occurred with predominant retention of configuration. Unrearranged external substitution product, R-Y, was mainly of inverted configuration.
The exo-amine (2) gave less elimination and [equation displayed], and hydrocarbon rearrangement. Both internal and external substitution occurred
with predominant retention of configuration at the unrearranged position. There was some evidence that this amine reacted, to a small extent, through a non-chair conformer. The model proposed by Maskill and Whiting involving an ion pair separated by
molecular nitrogen was used, with minor alterations, to
accommodate these results.
The products of deamination of amines (3) and (4) were similar but not identical and included large amounts of hydrocarbon and products derived from carbon migration. However, both amines showed a tendency to maintain their structural identity when compared with the products of solvolysis of the 3 corresponding tosylates. The results suggest initial formation of the classical carbonium ions (6) and (7) from (3) and (4) respectively followed by relaxation to a common non-classical ion (8).
[diagrams displayed]
Deamination of (5) gave a very different distribution of products from (3) and (4). Very little rearranged product was observed and most of the substitution was with retention of configuration although a small but significant amount was inverted,
Initial formation of a classical carbonium ion, with nominal
structure (6), followed by relaxation to the non-classical
ion (9) is proposed as a possible mechanism. The different fates
[diagram displayed]
of the initially formed carbonium ions from (5) and (3) are thought to be due to the different positions of the counter-ions.
The mode of decomposition of adamant-2-yl-0NN-azoxy-tosylate (10) has been investigated as a link between deamination and tosylate solvolysis which would be amenable to kinetic studies. Preliminary results suggested that the mechanism is ionic, the activated complex having carbonium ion character. Isolation of 2-adamantyl tosylate from the ethanolysis of (10) is presented as evidence for internal return of tosylate anion in solvolysis of alkyl tosylates. [diagram displayed
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Coming Soon to ACRL | NEC: A New Open Access Repository for Conference Proceedings and Other Materials
This poster describes a new open access repository being developed to store and disseminate digital materials arising from ACRL | NEC conferences and SIG events. Come learn more about the repository and how your ACRL | NEC group can participate
Inhibition of Nitric Oxide and Soluble Guanylyl Cyclase Signaling Affects Olfactory Neuron Activity in the Moth, \u3cem\u3eManduca sexta\u3c/em\u3e
Nitric oxide is emerging as an important modulator of many physiological processes including olfaction, yet the function of this gas in the processing of olfactory information remains poorly understood. In the antennal lobe of the moth, Manduca sexta, nitric oxide is produced in response to odor stimulation, and many interneurons express soluble guanylyl cyclase, a well-characterized nitric oxide target. We used intracellular recording and staining coupled with pharmacological manipulation of nitric oxide and soluble guanylyl cyclase to test the hypothesis that nitric oxide modulates odor responsiveness in olfactory interneurons through soluble guanylyl cyclase-dependent pathways. Nitric oxide synthase inhibition resulted in pronounced effects on the resting level of firing and the responses to odor stimulation in most interneurons. Effects ranged from bursting to strong attenuation of activity and were often accompanied by membrane depolarization coupled with a change in input resistance. Blocking nitric oxide activation of soluble guanylyl cyclase signaling mimicked the effects of nitric oxide synthase inhibitors in a subset of olfactory neurons, while other cells were differentially affected by this treatment. Together, these results suggest that nitric oxide is required for proper olfactory function, and likely acts through soluble guanylyl cyclase-dependent and -independent mechanisms in different subsets of neurons
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A New Green Salamander in the Southern Appalachians: Evolutionary History of Aneides aeneus and Implications for Management and Conservation with the Description of a Cryptic Micro-endemic Species (vol 107, pg 748, 2019)
Depressive symptoms in asymptomatic stage B heart failure with Type II diabetic mellitus.
BackgroundThe presence of concomitant Type II diabetic mellitus (T2DM) and depressive symptoms adversely affects individuals with symptomatic heart failure (HF).HypothesisIn presymptomatic stage B HF, this study hypothesized the presence of greater inflammation and depressive symptoms in T2DM as compared to non-T2DM Stage B patients.MethodsThis cross-sectional study examined clinical parameters, inflammatory biomarkers, and depressive symptoms in 349 T2DM and non-T2DM men with asymptomatic stage B HF (mean age 66.4 years ±10.1; range 30-91).ResultsFewer diabetic HF patients had left ventricular (LV) systolic dysfunction (P < .05) although more had LV diastolic dysfunction (P < .001). A higher percentage of T2DM HF patients were taking ACE-inhibitors, beta-blockers, calcium channel blockers, statins, and diuretics (P values < .05). T2DM HF patients had higher circulating levels of interleukin-6 (IL-6) (P < .01), tumor necrosis factor-alpha (P < .01), and soluble ST2 (sST2) (P < .01) and reported more somatic/affective depressive symptoms (Beck Depression Inventory II) (P < .05) but not cognitive/affective depressive symptoms (P = .20). Among all patients, in a multiple regression analysis predicting presence of somatic/affective depressive symptoms, sST2 (P = .026), IL-6 (P = .010), B-type natriuretic peptide (P = .016), and sleep (Pittsburgh Sleep Quality Index [P < .001]) were significant predictors (overall model F = 15.39, P < .001, adjusted R2 = .207).ConclusionsSomatic/affective but not cognitive/affective depressive symptoms are elevated in asymptomatic HF patients with T2DM patients. Linkages with elevated inflammatory and cardiac relevant biomarkers suggest shared pathophysiological mechanisms among T2DM HF patients with somatic depression, and these conditions are responsive to routine interventions, including behavioral. Copyright © 2019 John Wiley & Sons, Ltd
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