A Comparison of some Upland and Valley Soils in the Ungava-Labrador Peninsula

Thirteen soil profiles from northern Québec and Labrador, Canada, near the northern tree-line, were sampled and analysed. Five of these, located on poorly to imperfectly drained sites, are strongly cryoturbated soils with permafrost at a shallow depth. Below the surface horizon they have very uniform profile distributions of pH, carbon and extractable iron and aluminum due to the active mixing of the horizons. The eight soils from well-drained sites have profiles similar to those of soils in similar settings in more temperate climatic regions. One of these, developed in one of the most northerly valleys having a black spruce-larch forest vegetation, has the characteristics of a podzol (spodosol) except that the podzolic B (spodic) horizon is too thin. The other seven profiles all have color B horizons, although the coarse texture prevents their classification as cambic horizons; these soils all have carbon-rich A horizons varying in thickness from 1.5 to 20 cm. Soil temperature at 50 cm depth closely follows the elevational and latitudinal distribution of the soils; a range of 0 to 10° C was observed. Soil development, measured as depth of solum, organic carbon accumulation or degree of B horizon development, is closely related to soil temperature and site position. The presence of permanently frozen ice layers at shallow depth has a marked influence on soil genesis and the properties of the resultant soils.Treize profils de sols provenant du Nouveau-Québec et du Labrador, près de la limite septentrionale des arbres, furent échantillonnés et analysés. Aux endroits mal drainés, cinq de ces profils sont fortement cryoturbés et se caractérisent par la présence du pergélisol à de faibles profondeurs. Sous la surface, le brassage des horizons associé à la cryoturbation tend à uniformiser la distribution verticale du pH, du carbone, et du fer et de l'aluminium extractibles. Les huit sols bien drainés possèdent des profils comparables à ceux qui se développent sur des sites bien drainés des régions plus tempérées. Un de ces sols sous couvert forestier, développé dans une des dernières vallées au nord a toutes les caractéristiques d'un podzol (spodosol) si ce n'est que l'horizon B pod-zolique (spodique) est trop mince. Les sept autres sols ont des horizons B identifiables par leur couleur; tous ces sols ont des horizons A riches en carbone dont l'épaisseur varie entre 1,5 et 20 cm. Il existe une étroite relation entre la température des sols à 50 cm de profondeur et la distribution altitudinale et latitudinale de ces sols; des températures variant entre 0 et 100C ont été enregistrées. Il semble également exister une relation entre le développement pédogénétique et la température des sols ainsi que la position des sites. La présence de couches de glace, a faible profondeur, influence la pédogénèse et les différentes propriétés des sols qui en résultent.Von dreizehn Boden-Profilen von Nord-Quebec und Labrador, Kanada, nahe der nôrdlichen Baumgrenze wurden entnommene Proben analysiert. Davon sind fùnf, die von schlecht drânierten Gelànden stammen, stark kryoturbatisch und zeichnen sich durch das Vorkommen von Dauerfrost in geringen Tiefen aus. Unter der Oberflàche fùhrt die Verknetung der Horizonte in Verbindung mit der Kryoturbation zu einer gleichmâBigen vertikalen Verteilung der Sàure, des Kohlenstoffs und des gewinnbaren Eisens und Aluminiums. Die acht gut drânierten Bôden besitzen Profile, die mit denen der gut drânierten Bôden der mehr gemâGigten Gebiete vergleichbar sind. Einer dieser Bôden, der sich in einem der letzten bewaldeten Tàler im Norden entwickelt hat, besitzt aile Eigenschaften eines Podsol, auRer dafi der podsolige B-Horizont zu dùnn ist. Die sieben anderen Bôden haben aile B-Ho-rizonte, identif iziert durch ihre Farben ; ail dièse Bôden besitzen an Kohlenstoff reiche A-Horizonte, deren Dicke zwischen 1,5 und 20 cm variiert. Es besteht eine enge Beziehung zwischen der Bodentemperatur in 50 cm Tiefe und der Hôhen- und Breiten-Verteilung dieser Bôden ; Temperaturen zwischen O0C und 100C wurden registriert. Eine Beziehung scheint auch zu bestehen zwischen der bodengenetischen Entwicklung und der Temperatur der Bôden sowie der Lage der Vorkommen. Das Vorhandensein von Eisschichten in mâfliger Tiefe beeinfluBt die Bodenentwick-lung und die verschiedenen Eigenschaften der Bôden, die sich hieraus ergeben

La genèse des podzols

Les podzols sont des sols acides de milieux forestiers caractérisés par l'accumulation de fer (Fe) et d'aluminium (Al) dans l'horizon B (horizon B podzolique). Ils couvrent de vastes étendues des zones boréales et tempérées humides et sont associés à des substrats à texture grossière. La connaissance des mécanismes responsables de la formation des podzols est essentielle à la compréhension, la modélisation et la gestion des écosystèmes forestiers, agricoles et aquatiques et à la prévision de leurs réactions face à des changements des conditions environnementales. Quatre théories majeures, ou modèles conceptuels, ont été proposées afin de représenter la genèse des podzols : la théorie des fulvates (Stobbe et Wright, 1959; McKeague et al., 1978), la théorie de la proto-imogolite (Farmer et al., 1980; Anderson et al., 1982), la théorie des compartiments chimiques (Ugolini et Dahlgren, 1987) et la théorie des polymères d'AI (Browne, 1995). Celles-ci ont mis en relief le rôle de certains processus tels que la création et le transport de complexes organo-métalliques, la synthèse de la proto-imogolite et la néoformation d'imogolite, l'altération des minéraux par l'acide carbonique (H2CO3) ainsi que la formation de complexes polymériques dissouts de type Al-silice (Si). L'importance accordée à chacun de ces processus varie toutefois en fonction de la nature des milieux prospectés lors de la définition d'une théorie particulière. L'absence d'une théorie globale et intégrée de la genèse des podzols est aussi liée à la compréhension incomplète de la dynamique des podzols, à l'omission de certains processus importants et à l'apparente opposition entre les théories.Podzols are acidic soils of forested areas characterized by the pedogenic accumulation of iron (Fe) and aluminum (Al) in the B horizon (podzolic B horizon). Podzols cover large areas of the wet temperate and boreal zones and are associated to coarse parent materials. Knowledge on podzol genesis is of considerable interest with respect to the understanding, modelling and management of forested, agricultural and aquatic ecosystems and to the forecasting of soil changes in response to environmental perturbations. Four theories, or conceptual models, were formulated to describe podzol formation: the fulvate theory (Stobbe and Wright, 1959; McKeague etal., 1978), the proto-imogolite theory (Farmer et al., 1980; Anderson etal., 1982), the theory of chemical compartments (Ugolini and Dahlgren, 1987) and the Al polymer theory (Browne, 1995). Each theory emphasizes the role of specific processes such as the formation and transport of organo-metallic complexes, proto-imogolite synthesis and imogolite precipitation, mineral weathering by carbonic acid (H2CO3) and the formation of poiynuclear Al-silicate soluble complexes. However, the relative importance attributed to any of these processes varies as a function of the properties of the sites explored by the authors of a given theory. The absence of an integrated theory of podzol genesis also reflects our incomplete understanding of podzol dynamics, the fact that important processes have been left out and the apparent opposition between theories.Podsols sind saure Bôden waldiger Milieus, charakterisiert durch die Anhâufung von Eisen (Fe) und Aluminium (Al) im B-Horizont (podsolischer B-Horizont). Sie bedecken ausgedehnte Flâchen der nôrdlichen und feuchten gemassigten Gebiete und werden mit Substraten grober Textur in Verbindung gebracht. Die Kenntnis der Mechanismen, die zur Bildung der Podsols fuhrt, ist unerlàsslich fur das Ver-stàndnis, die Modellierung und Bewirtschaftung der Forst-, Landwirtschaft- und Wasser-Okosysteme und fur die Vorhersage ihrer Reaktionen auf Verànderungen in den Umweltbedingungen. Vier Haupttheorien oder Denkmodelle wurden zur Darstellung der Genèse der Podsols vorgeschlagen : die Theorie der Fulvate (Stobbe und Wright, 1959; McKeague etal., 1978), die Proto-Imogolit-Theorie (Farmer et al., 1980 ; Anderson et al.,1982), die Théorie der chemischen Abteilungen (Ugolini und Dahlgren, 1987) und die Al-Polymer-Theorie (Browne, 1995). Diese Theorien haben die RoIIe bestimmter Prozesse hervorgehoben, wie die Bildung und den Transport organischmetallischer Einheiten, die Synthèse des Proto-lmogolit und die Neubildung von lmogolit, die Verânderung der Minérale durch die Kohlensâure (H2CO3) sowie die Bildung von aufgelôsten Polymer-Einheiten des Typs Al-Silizium (Si). Die Bedeutung, die jedem dieser Prozesse zugemessen wird, variiert jedoch je nach der Natur der bei der Aufstellung einer bestimmten Théorie untersuchten Milieus. Das Fehlen einer globalen und integrierten Théorie der Entstehung der Podsols hàngt auch mit dem unvollstàndigen Verstândnis der Dynamik der Podsols, dem Weglassen gewisser wichtiger Prozesse und dem offenbaren Gegensatz zwischen den Theorien zusammen

GenTAC registry report: Gender differences among individuals with genetically triggered thoracic aortic aneurysm and dissection

Previous data suggest women are at increased risk of death from aortic dissection. Therefore, we analyzed data from the GenTAC registry, the NIH‐sponsored program that collects information about individuals with genetically triggered thoracic aortic aneurysms and cardiovascular conditions. We performed cross‐sectional analyses in adults with Marfan syndrome (MFS), familial thoracic aortic aneurysm or dissection (FTAAD), bicuspid aortic valve (BAV) with thoracic aortic aneurysm or dissection, and subjects under 50 years of age with thoracic aortic aneurysm or dissection (TAAD <50 years). Women comprised 32% of 1,449 subjects and were 21% of subjects with BAV, 34% with FTAAD, 22% with TAAD <50 years, and 47% with MFS. Thoracic aortic dissections occurred with equal gender frequency yet women with BAV had more extensive dissections. Aortic size was smaller in women but was similar after controlling for BSA. Age at operation for aortic valve dysfunction, aneurysm or dissection did not differ by gender. Multivariate analysis (adjusting for age, BSA, hypertension, study site, diabetes, and subgroup diagnoses) showed that women had fewer total aortic surgeries (OR = 0.65, P  < 0.01) and were less likely to receive angiotensin converting enzyme inhibitors (ACEi; OR = 0.68, P  < 0.05). As in BAV, other genetically triggered aortic diseases such as FTAAD and TAAD <50 are more common in males. In women, decreased prevalence of aortic operations and less treatment with ACEi may be due to their smaller absolute aortic diameters. Longitudinal studies are needed to determine if women are at higher risk for adverse events. © 2013 Wiley Periodicals, Inc.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/97193/1/35836_ftp.pd

Relapse prevention for addictive behaviors

The Relapse Prevention (RP) model has been a mainstay of addictions theory and treatment since its introduction three decades ago. This paper provides an overview and update of RP for addictive behaviors with a focus on developments over the last decade (2000-2010). Major treatment outcome studies and meta-analyses are summarized, as are selected empirical findings relevant to the tenets of the RP model. Notable advances in RP in the last decade include the introduction of a reformulated cognitive-behavioral model of relapse, the application of advanced statistical methods to model relapse in large randomized trials, and the development of mindfulness-based relapse prevention. We also review the emergent literature on genetic correlates of relapse following pharmacological and behavioral treatments. The continued influence of RP is evidenced by its integration in most cognitive-behavioral substance use interventions. However, the tendency to subsume RP within other treatment modalities has posed a barrier to systematic evaluation of the RP model. Overall, RP remains an influential cognitive-behavioral framework that can inform both theoretical and clinical approaches to understanding and facilitating behavior change

Constraining soil mineral weathering 87Sr/86Sr for calcium apportionment studies of a deciduous forest growing on soils developed from granitoid igneous rocks

We used 87Sr/86Sr as a proxy for Ca to apportion the contribution of atmospheric deposition and soil mineral weathering sources to the Ca pools in trees in a small forested watershed of southern Quebec. The effects of topography and forest stand composition were assessed by dividing the watershed into three study zones representing two elevations and differences in tree species. Apportionment calculations show that all tree species studied contained Ca that is dominantly sourced from soil mineral weathering (averaging 85%), due to the presence in the soils of easily weathered Ca-bearing minerals such as calcite and apatite as well as the relatively deep rooting habits (reaching the mineral soil) of the tree species. Calcium pools in trees are shifted towards the atmospheric component on hilltops due to the filtering of dry aerosols of the tree canopies which are more exposed to atmospheric circulation than trees at the bottom of the slopes, although some variability in soil bulk chemistry and mineralogy in the watershed obscures the full extent of this phenomenon. The buildup and recycling of Ca in the soil-vegetation system, with the forest floor acting as the major accessible Ca pool for the tree roots, must be considered when interpreting apportionment calculations. This work supports other Ca cycling models in forests suggesting that topography can influence the balance of Ca captured from atmospheric sources by trees, even in cases where mineral weathering is the dominant source of Ca nutrition in trees

Partitioning of the source of leaf calcium of American beech and sugar maple using leaf Ca/Sr ratios: A predominantly surficial but variable depth of Ca uptake

Background and Aims Reduced availability of calcium (Ca) has been linked to maple forest decline. We therefore aimed at assessing the contribution of the different soil horizons to leaf Ca of competing beech (Fagus grandifolia Ehrh.) and sugar maple (Acer saccharum Marsh.) to better understand the dynamics of Ca uptake. Methods Leaf Ca was partitioned using the Ca/Sr ratio approach in two mature forests of southern Quebec. A mass balance was also used at one site to validate the results obtained with the Ca/Sr approach. Results The L and F horizons contributed most of the leaf Ca of beech and maple with likely small contributions from the upper B and/or H/Ahe horizons. Leaf Ca/Sr ratios of beech were however more variable than those of maple. Using a mass balance, the organic horizons and upper mineral soil horizons were found to provide ca. 80 and 20%of tree Ca uptake, respectively. Conclusion Beech and maple Ca uptake depth apportionment is on average similar but beech is likely more plastic in sourcing soil Ca. The low contribution of the mineral soil to leaf Ca at our sites can be linked to less favorable conditions for Ca uptake likely associated with low Ca/Al ratios

Agricultural Practices Influence Dissolved Nutrients Leaching through Intact Soil Cores

ABSTRACT high water table was set in the Netherlands suggesting that fertilizing soils with a combination of inorganic and Yet, Eisenhauer et al. (1993) found that greater percolaorganic fertilizers might be a good way to reduce both NO 3 -N and tion of water through no-till than plowed soils led to NO 3 -N leaching (Kanwar et al., 1995; Lamb et al., 1998). P concentration (R 2 ϭ 0.50) and soil P saturation ratio (M3-PSR) (R 2 ϭ Fewer studies have investigated how tillage affects P 0.55). These results suggest that the leaching of dissolved N and leaching, bu