Temperature-sensitive Tien Shan tree ring chronologies show multi-centennial growth trends

Two millennia-length juniper ring width chronologies, processed to preserve multi-centennial growth trends, are presented for the Alai Range of the western Tien Shan in Kirghizia. The chronologies average the information from seven near-timberline sampling sites, and likely reflect summer temperature variation. For comparison, chronologies are also built using standard dendrochronological techniques. We briefly discuss some qualities of these "inter-decadal” records, and show the low frequency components removed by the standardization process include a long-term negative trend in the first half of the last millennium and a long-term positive trend since about AD 1800. The multi-centennial scale Alai Range chronologies, where these trends are retained, are both systematically biased (but in an opposite sense) in their low frequency domains. Nevertheless, they represent the best constraints and estimates of long-term summer temperature variation, and reflect the Medieval Warm Period, the Little Ice Age, and a period of warming since about the middle of the nineteenth centur

ON SOLVABILITY OF THE BOUNDARY VALUE PROBLEMS FOR HARMONIC FUNCTION ON NONCOMPACT RIEMANNIAN MANIFOLDS

We study questions of existence and belonging to the given functional class of solutions of the Laplace-Beltrami equations on a noncompact Riemannian manifold M with no boundary. In the present work we suggest the concept of φ-equivalency in the class of continuous functions and establish some interrelation between problems of existence of solutions of the Laplace-Beltrami equations on M and off some compact B ⊂ M with the same growth "at infinity". A new conception of φ-equivalence classes of functions on M develops and generalizes the concept of equivalence of function on M and allows us to more accurately estimate the rate of convergence of the solution to boundary conditions

ON SOLVABILITY OF THE BOUNDARY VALUE PROBLEMS FOR THE INHOMOGENEOUS ELLIPTIC EQUATIONS ON NONCOMPACT RIEMANNIAN MANIFOLDS

We study questions of existence and belonging to a given functional class of solutions of the inhomogeneous elliptic equations ∆u - c(x)u = g(x), where c(x) >(=)0, g(x) are H¨older fuctions on a noncompact Riemannian manifold M without boundary. In this work we develop an approach to evaluation of solutions to boundary-value problems for linear and quasilinear equations of the elliptic type on arbitrary noncompact Riemannian manifolds. Our technique is essentially based on an approach from the papers by E. A. Mazepa and S. A. Korol’kov connected with an introduction of equivalency classes of functions and representations. We investigate the relationship between the existence of solutions of this equation on M and outside some compact set B ⊂ M with the same growth "at infinity"

Methanolysis of N-acetoxy-N-n-propyloxy-N’,N’-dimethylurea in different conditions

The methanolysis of N-acetoxy-N-n-propyloxy-N’,N’-dimethylurea in the presence of strong acids at room temperatures or in the boiling methanol yields N,N-dimethoxy-N’,N’-dimethylurea as final product. Primarily the nucleophilic substitution acetoxy group at nitrogen on methoxy group arises. At second stage the transesterification of N,N-dialkoxyamino group of formed N-methoxy-N-n-propyloxy-N’,N’-dimethylurea take place

New approach to N,N-dialkoxy-N'-arylureas and N,N-dialkoxycarbamates

Methanolysis of N-chloro-N-alkoxy-N'-arylureas in the presence of silver trifluoroacetate gives the corresponding N,N-dialkoxy-N'‑arylureas, whereas N-chloro-N-alkoxycarbamates react with alcohols in the presence of silver trifluoroacetate to afford N,N-dialkoxycarbamates

Pyramidal amide nitrogen in N-acyloxy-N-alkoxyureas and N-acyloxy-N-alkoxycarbamates

The XRD studies of N-acyloxy-N-alkoxyamides 1, 2 have revealed a highly pyramidal configuration of amide nitrogen in the O–N–O group

Synthesis and structure of N-alkoxyhydrazines and N-alkoxy-N',N',N'-trialkylhydrazinium salts

New types of 1,1,1-trialkyl-2-alkoxyhydrazinium chlorides and N-alkoxyhydrazines were obtained by reactions of N-chloro-N-alkoxyureas with trimethylamine or 1,4-diaza[2.2.2]bicyclooctane and by reactions of methyl N chloro-N-methoxycarbamate with potassium salt of N-acetylbenzenesulfonylamide. The XRD studies of N,N' bis(methoxycarbonyl)-N,N'-dimethoxyhydrazine, N'-methoxy-N'‑methoxycarbonyl-N-acetylbenzenesulfonylhydrazide and 1,1,1-trimethyl-2-methoxyhydrazinium perchlorate revealed the pyramidal configuration of the central nitrogen atoms in O–N–N geminal system, unusual elongation of N–N+ bond and shortening of N–OMe bond in 1,1,1-trimethyl-2-methoxyhydrazinium perchlorate

The properties and structure of N-chloro-N-methoxy-4-nitrobenzamide

The XRD study of N-chloro-N-methoxy-4-nitrobenzamide revealed the high pyramidality degree of its amide nitrogen atom in O–N–Cl moiety. N-Chloro-N-methoxy-4-nitrobenzamide reacts with AcONa in MeCN selectively forming N-acetoxy-N-methoxy-4-nitrobenzamide, whereas its methanolysis in the presence of AcONa yields N,N' bis(4-nitrobenzoyl)-N,N'-dimethoxyhydrazine