Dendroclimatology uses precisely dated tree-ring series and climate measurements to reconstruct climate for periods prior to instrumented records. Dendroclimatology requires a predictable, relationship between growth and climate. Tree-ring series from silver fir in Slovenia and red spruce in the northeastern US were calibrated to monthly climate variables for two periods, corresponding approximately to the first and second halves of the 20th Century. Bootstrapped response function analysis indicated that growth during the two periods was associated with markedly different variables of monthly mean temperature and monthly total precipitation. These findings suggest caution in dendroclimatic reconstruction and are interpretable as indications that the relationship of tree growth to climate may have changed during the 20th Century.

Cambial electrical resistance (CER) was used as an objective measure of vitality of silver fir (Abies alba) in the forests of Slovenia. Trees were rated during the growing season by CER and a subjective crown status index (CSI). Both CER and CSI were inversely correlated to annual ring width increment. Using both CER and CSI, fir were assigned to vitality and vigour categories. Inferences made from these categories and radial growth trends indicated that ring growth decreased prior to the development of canopy symptoms. This decrease in ring growth would have been detected as an increase in CER. This pattern of decline is consistent with the decline of trees due to chronic below-ground stress. Variation in CER was due both to the vascular cambium and to the thickness of the nonconducting phloem.

Polluted air masses from the industrialized northeastern corridor of the United States flow through Acadia National Park, Maine, U.S.A. The polluted air masses create elevated ozone episodes throughout the growing season, causing visible foliar damage to some native plant species. This study used dendroclimatic techniques to investigate the possibility that elevated ozone levels adversely affected white pine (Pinus strobus L.) radial growth rates. Tree-ring cores were extracted from white pine trees in eight separate stands within the park. Tree-ring indices were then regressed with ozone variables to model the effects of elevated ozone levels on tree growth under field conditions. Models from seven of the eight stands documented negative associations between tree-ring indices and ozone levels that were stronger than any associations between tree-ring indices and climate. The modeled growth-ozone associations exhibited stand-level variations, suggesting that site characteristics affect tree responses to ozone pollution.

Root chemistry is being increasingly used as a marker of biologically relevant soil chemistry. To evaluate this marker, we determined the precision of measurement, the effect of organic soil horizon, and the effect of stand elevation on the chemistry of fine root tips of red spruce (Picea rubens Sarg.). Fine root tips were collected from the F and H horizons of the forest floor of nine locations. Six of the locations were selected as pairs that differed in elevation. The concentrations of Al, Ca, Mg, and Fe in fine root tip collections were determined by direct current plasma emission spectroscopy. Element concentrations were not well correlated between collections made from the F and H layers associated with individual trees. The concentration of Ca was significantly higher and the concentrations of Al and Fe were significantly lower in fine root tips collected from the F than in tips collected from the H horizons. Fine root tips collected from the higher elevation member of paired locations yielded a higher Al:Ca ratio than did those collected from the lower elevation member. These results indicated the need to stratify fine root collections by soil horizon within the forest floor.

Summary In sapwood challenge experiments in Acer rubrum , columns of discolouration initiated by wounding and inoculation with pioneer fungi ( Cephalosporium sp., Phialophora sp.) were similar in size to untreated wounds. Inoculation with decay fungi ( Pleurotus ostreatus, Trametes versicolor ) produced larger columns of wound‐initiated discolouration. The removal of bark around a bore wound caused a significantly larger column to form compared to the sum of the columns inititiated by separate wounds. Stage‐I discoloured wood, not associated with obviously rotted wood, had concentrations of mobile cations and soluble phenols similar to sapwood. Stage‐II discoloured wood, spatially associated with rotted wood, was frequently bounded by a chemically distinct boundary layer and the discoloured wood contained significantly greater concentrations of mobile cations and soluble phenols than stage‐I discoloured wood.

Recently, the CS-3000(R) Plus Blood Cell Separator with the TNX-6 platelet separation chamber insert has been furnished with a small-volume (30-ml) collection chamber. In this study, a platelet synthetic medium containing glucose and bicarbonate (PSM) was used for resuspension and storage of this highly concentrated platelet product. Eighteen donors participated in a paired study design where each participant donated platelets on two occasions, once following collection in a standard chamber with resuspension and storage in plasma and once following collection in the new chamber with resuspension and storage in PSM. Substantially higher total platelet counts were obtained using platelets collected in the small chamber and stored in PSM as compared to control (4.4+/-0.9x10(11) vs. 3.5+/-0.9x10(11) platelets, p<0.01 by paired t test). After 5 days of storage, PSM-stored platelets demonstrated higher ATP levels, less lactate dehydrogenase in the supernatant and increased lactate production with resulting lower pH at day 5 of storage (6.94+/-0.15 vs. 7.08+/-0.09, p<0.05). There were no statistically significant differences of the survival by multiple-hit estimation of PSM-stored as compared to plasma-stored platelets as determined by In-111 labeling and infusion. A slight decrease in the initial percent recovery with the additive-suspended as compared to suspended plasma cells was noted: 50+/-8 versus 54+/-9%, respectively (p<0.05). In conclusion, the CS-3000 Plus/TNX-6 apheresis system with a new reduced-volume collection chamber and an additive solution provides a plasma-poor and highly concentrated platelet product with satisfactory in vivo viability and in vitro functional characteristics after 5 days of storage.

The inoculation of sugar maple (Acer saccharum Marsh.) saplings with Ceratocystis virescens (Davidson) C. Moreau (=Ceratocystis coerulescens (Munch) Bakshi), the causal agent of sapstreak disease, resulted in infection and the development of extensive discoloration. A distinct column boundary layer formed between the discolored wood and sapwood in wounded saplings infected with C. virescens and in noninoculated controls. Elemental markers of discoloration and column boundary layer formation were similar for infected and noninoculated control saplings. The extensive damage caused by sapstreak disease is interpreted as resulting from the rapid spread of the pathogen prior to column boundary layer formation.

Primary bovine fibroblasts derived from foetal palate can be transformed by bovine papillomavirus type 4 DNA only in the presence of an activated ras gene, indicating that the virus does not encode all the information required for morphological transformation of non-established cells. A subgenomic fragment containing the complete E8 and E7 open reading frames (ORFs) induces transformation in cooperation with activated ras but transformation is abolished when the E7 ORF is deleted at the 3' end, showing that this ORF encodes a necessary transforming function. Transformation is more aggressive when the E8 and E7 ORFs are placed under the transcriptional control of the long terminal repeat of the mouse Moloney leukaemia virus, suggesting that the degree of transformation is dependent on the level of expression of these genes.

Anomalies in the radial concentration trends of Ca2+, Mg2+, and other divalent cations in the stemwood of red spruce (Picearubens Sarg.) occurred in trees grown in New England, Tennessee, and North Carolina. These anomalies may be assumed to result from changes in sap chemistry. These inferred changes in sap chemistry were the expected result of changes of divalent cation availability in forest soils. The patterns of these anomalies may be interpreted as a signal of a regional mobilization of cations in the rooting zone of red spruce. The anomalous increase in divalent cations present in wood formed in the mid-1900s is coincident both with rapid increases in SOx and NOx deposition in eastern North America and with increases in radial growth increment. The anomalous decrease in divalent cations in wood formed in the late-1900s is coincident with declines in radial increment. Comparisons with divalent cation trends in eastern hemlock (Tsugacanadensis (L.) Carr.), Fraser fir (Abiesfraseri (Pursh) Poir.), and yellow birch (Betulaalleghaniensis Britt. = B. lutea Michx.) suggested that these anomalies were not restricted to red spruce. Radial concentration trends of 90Sr introduced to the environment through radioactive fallout during the 1950s and 1960s were used to investigate the physiology of these divalent cation concentration anomalies. The distributions of 90Sr were also used to estimate the turnover rates for the nutritionally available pools of alkaline earths such as calcium.

Wounding the cambium of red maple ( Acer rubrum L.) altered peroxidase isoenzymes and enhanced the activities of peroxidase and indole-3-acetic acid oxidase in homogenates of adjacent cambial tissue. Four separate experiments were conducted, in May and July in each of two successive years. Wounds made in July caused greater increases in enzyme activity than those made in May. Alterations in peroxidase isoenzyme pattern were consistent for all experiments. These changes are intrepretable as aspects of the molecular regulation of barrier zone formation.

Prolonged suppression of cambial growth has apparently caused a decline in radial growth in many mature red spruce, Picea rubens. Surveys indicate that this decline occurs in trees throughout the natural range of red spruce and is independent of elevation, tree size, and age class. In addition, crowns of mature red spruce at high elevations across the northeastern United States have been dying back. Understanding the physiological basis for the growth decline is essential for the judicious management of the red spruce resource. A sequence of events is inferred through which an imbalance of aluminum and calcium in the fine root environment reduces the rate of wood formation, decreases the amount of functional sapwood and live crown, and leaves large trees more vulnerable to extant secondary diseases and insect pests.

Cambial electrical resistance (CER) was related to the number of cells per radial file of vascular cambium in dominant and codominant balsam fir (Abiesbalsamea (L.) Mill.) trees sampled during the growing season. Scanning electron microscopy (SEM) was used to examine the vascular cambial zone (VCZ) of balsam fir during the growing and dormant seasons. Trees selected for SEM were categorized as having growing season CER < 10 kΩ or CER > 12 kΩ. The two growing trees with CER < 10 kΩ had a mean of seven cells per radial file of VCZ in contrast with four cells per radial file in the two trees of CER > 12 kΩ. Trees of either growing season category had dormant season CER > 12 kΩ and four cells per radial file of VCZ. The relationship between CER and the number of cells per radial file of VCZ supports the hypothesis relating CER to periodic growth rate in balsam fir.

Communications on Pure and Applied MathematicsVolume 18, Issue 3 p. 415-441 Article Some remarks on a paper of Calderòn on existence and uniqueness theorems for systems of partial differential equations† K. T. Smith, K. T. Smith University of WisconsinSearch for more papers by this author K. T. Smith, K. T. Smith University of WisconsinSearch for more papers by this author First published: August 1965 https://doi.org/10.1002/cpa.3160180304Citations: 4 † This paper was written while the author was a Visiting Member of the Courant Institute of Mathematical Sciences, New York University. This Visiting Membership is supported by the National Science Foundation, under grant number NSF-GP-1669. Reproduction in whole or in part is permitted for any purpose of the United States Government. AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat Citing Literature Volume18, Issue3August 1965Pages 415-441 RelatedInformation

In 1954 N. Aronszajn [l] proved an inequality for formally positive integro-differential forms which has been found very interesting in itself and which has had a strong influence on subsequent progress in elliptic partial differential equations.We propose to extend this inequality in respect to the class of possible domains of integration and in respect to the kind of norms involved.Let {Pj} be a finite set of differential operators of order m with continuous coefficients on the closure G of a domain G C.R n > Suppose that the characteristic polynomials 2 pj(x, £) have no common real zero 7^0 for #£G and no common complex zero 5*0 for xÇzG -G.Then an inequality of the formJo Jo holds for all functions u of class C m on G and all derivatives D m u of order m.The inequality is valid for a large class of bounded domains G-finite sums of those with boundary of Lipschitz graph type [2 ; 4]including, for example, all with smooth boundary, all convex domains, and all finite sums of such. 3 With minor modifications it is also valid for quite a large class of unbounded domains.The full details of the statement of the theorem, as well as the proof, will be given in another paper.Here we prefer to show the proof in a case which, though special, still contains the idea.We will suppose :

: A proof is presented of the theorem that if B is a Banach space and if T is a completely continuous operator in B, there then exist proper invariant subspaces of T. The proof assumes strong convergence, complete continuity in the sense that any bounded set is transformed by T into a set with compact closure, and a strictly convex norm. The same theorem is proved for a Hilbert space; the theorem utilizes the concepts of weak and strong convergenece of elements and operators. The simplifying feature of the latter proof is that the metric propjections coincide with the usual orthogonal projections.