An approximate MO-LCAO-SCF method including overlap

Molecular orbital method based on atomic self consistent field functions and applicable where pi electron restrictions not fulfille

Fast Structuring of Radio Networks for Multi-Message Communications

We introduce collision free layerings as a powerful way to structure radio networks. These layerings can replace hard-to-compute BFS-trees in many contexts while having an efficient randomized distributed construction. We demonstrate their versatility by using them to provide near optimal distributed algorithms for several multi-message communication primitives. Designing efficient communication primitives for radio networks has a rich history that began 25 years ago when Bar-Yehuda et al. introduced fast randomized algorithms for broadcasting and for constructing BFS-trees. Their BFS-tree construction time was $O(D \log^2 n)$ rounds, where $D$ is the network diameter and $n$ is the number of nodes. Since then, the complexity of a broadcast has been resolved to be $T_{BC} = \Theta(D \log \frac{n}{D} + \log^2 n)$ rounds. On the other hand, BFS-trees have been used as a crucial building block for many communication primitives and their construction time remained a bottleneck for these primitives. We introduce collision free layerings that can be used in place of BFS-trees and we give a randomized construction of these layerings that runs in nearly broadcast time, that is, w.h.p. in $T_{Lay} = O(D \log \frac{n}{D} + \log^{2+\epsilon} n)$ rounds for any constant $\epsilon>0$. We then use these layerings to obtain: (1) A randomized algorithm for gathering $k$ messages running w.h.p. in $O(T_{Lay} + k)$ rounds. (2) A randomized $k$-message broadcast algorithm running w.h.p. in $O(T_{Lay} + k \log n)$ rounds. These algorithms are optimal up to the small difference in the additive poly-logarithmic term between $T_{BC}$ and $T_{Lay}$. Moreover, they imply the first optimal $O(n \log n)$ round randomized gossip algorithm

Mono- and di-anionic coordination modes of arylazosalicylates in their bis(η5-cyclopentadienyl)titanium(IV) complexes: Syntheses and crystal structures

The bis(η5-cyclopentadienyl)titanium(IV) complexes of 5-[(E)-2-(aryl)-1-diazenyl]-2-hydroxybenzoic acids (H2LXASA) where the aryl group is an X-substituted phenyl ring such that X = CH, COEt, CMe, CF, CCl, CBr and N have been synthesised. Two types of titanium(IV) compounds viz. (i) [Ti(η5-C5H5)2(O2CC6H3(OH-2)(NNC6H4(H-4)-5))2] (3) and [Ti(η5-C5H5)2(O2CC6H3(OH-2)(NNC6H4(OC2H5-4)-5))2] (4), and (ii) [Ti(η5-C5H5)2(O2CC6H3(O-2)(NNC6H4(CH3-4)-5))] (5), [Ti(η5-C5H5)2(O2CC6H3(O-2)(NNC6H4(F-4)-5))] (6), [Ti(η5-C5H5)2(O2CC6H3(O-2)(NNC6H4(Cl-4)-5))] (7), [Ti(η5-C5H5)2(O2CC6H3(O-2)(NNC6H4(Br-4)-5))] (8) and [Ti(η5-C5H5)2(O2CC6H3(O-2)(NNC5H4(N-4)-5))] (9) were isolated and characterised by IR, 1H and 13C NMR spectroscopic techniques. The crystal and molecular structures of 3–9 have been determined by single crystal X-ray crystallography. Compounds 3 and 4 conform to the formula Cp2Ti(HLXASA-κO)2 with a monodentate carboxylate ligand while those of 5–9 conform to Cp2Ti(LXASA-κ2O1,O2) with the dianions chelating the titanium atoms via carboxylate-O and hydroxy-O atoms. The common feature of the molecular structures is the adoption of distorted tetrahedral geometries based (Cp)2O2 donor sets. HydroxylOH…O(carbonyl) bonding leads to supramolecular chains in the crystal of 4 but, these are absent in 3. Persistent CpCH…O(carbonyl) interactions, with the carbonyl atoms accepting two or three such interactions, lead to supramolecular chains with helical (5, 7 and 8) or linear (6 and 9) topologies; C–X…π interactions also play an important role in the packing of 6–8

Spontaneous rupture of vaginal varicose veins mimicking placenta praevia

Vaginal varicosities are often an asymptomatic venous disorder that rarely occur in pregnant women. There is little information in medical literature concerning diagnosis and management.1 We present an isolated incident of spontaneous rupture of vulvar varicosities mimicking the presentation of placenta previa. It was successfully managed with a simple surgical approach done under local anesthesia

Self-stabilizing algorithms for Connected Vertex Cover and Clique decomposition problems

In many wireless networks, there is no fixed physical backbone nor centralized network management. The nodes of such a network have to self-organize in order to maintain a virtual backbone used to route messages. Moreover, any node of the network can be a priori at the origin of a malicious attack. Thus, in one hand the backbone must be fault-tolerant and in other hand it can be useful to monitor all network communications to identify an attack as soon as possible. We are interested in the minimum \emph{Connected Vertex Cover} problem, a generalization of the classical minimum Vertex Cover problem, which allows to obtain a connected backbone. Recently, Delbot et al.~\cite{DelbotLP13} proposed a new centralized algorithm with a constant approximation ratio of $2$ for this problem. In this paper, we propose a distributed and self-stabilizing version of their algorithm with the same approximation guarantee. To the best knowledge of the authors, it is the first distributed and fault-tolerant algorithm for this problem. The approach followed to solve the considered problem is based on the construction of a connected minimal clique partition. Therefore, we also design the first distributed self-stabilizing algorithm for this problem, which is of independent interest

Climate and changing winter distribution of alcids in the Northwest Atlantic

Population level impacts upon seabirds from changing climate are increasingly evident, and include effects on phenology, migration, dispersal, annual survivorship, and reproduction. Most population data on seabirds derive from nesting colonies; documented climate impacts on winter ecology are scarce. We studied interannual variability in winter abundance of six species of alcids (Charadriiformes, Alcidae) from a 58-year time series of data collected in Massachusetts 1954–2011. We used counts of birds taken during fall and winter from coastal vantage points. Counts were made by amateur birders, but coverage was consistent in timing and location. We found significant association between winter abundance of all six species of alcids and climate, indexed by North Atlantic Oscillation (NAO), at two temporal scales: (1) significant linear trends at the 58-year scale of the time series; and (2) shorter term fluctuations corresponding to the 5–8 year periodicity of NAO. Thus, variation in winter abundance of all six species of alcids was significantly related to the combined short-term and longer-term components of variation in NAO. Two low-Arctic species (Atlantic Puffin and Black Guillemot) peaked during NAO positive years, while two high Arctic species (Dovekie and Thick-billed Murre) peaked during NAO negative years. For Common Murres and Razorbills, southward shifts in winter distribution have been accompanied by southward expansion of breeding range, and increase within the core of the range. The proximate mechanism governing these changes is unclear, but, as for most other species of seabirds whose distributions have changed with climate, seems likely to be through their prey

Climate and changing winter distribution of alcids in the Northwest Atlantic

Population level impacts upon seabirds from changing climate are increasingly evident, and include effects on phenology, migration, dispersal, annual survivorship, and reproduction. Most population data on seabirds derive from nesting colonies; documented climate impacts on winter ecology are scarce. We studied interannual variability in winter abundance of six species of alcids (Charadriiformes, Alcidae) from a 58-year time series of data collected in Massachusetts 1954–2011. We used counts of birds taken during fall and winter from coastal vantage points. Counts were made by amateur birders, but coverage was consistent in timing and location. We found significant association between winter abundance of all six species of alcids and climate, indexed by North Atlantic Oscillation (NAO), at two temporal scales: (1) significant linear trends at the 58-year scale of the time series; and (2) shorter term fluctuations corresponding to the 5–8 year periodicity of NAO. Thus, variation in winter abundance of all six species of alcids was significantly related to the combined short-term and longer-term components of variation in NAO. Two low-Arctic species (Atlantic Puffin and Black Guillemot) peaked during NAO positive years, while two high Arctic species (Dovekie and Thick-billed Murre) peaked during NAO negative years. For Common Murres and Razorbills, southward shifts in winter distribution have been accompanied by southward expansion of breeding range, and increase within the core of the range. The proximate mechanism governing these changes is unclear, but, as for most other species of seabirds whose distributions have changed with climate, seems likely to be through their prey

Regulation of Iron-Related Molecules In the Rat Hippocampus: Sex- and Age-Associated Differences

Iron accumulation, especially that of free oxidized ferrous iron, has been shown to induce tissue oxidative damage and contribute to brain aging and the development of neurodegenerative disease. Here we examine whether sex and advanced age affect the expression of iron-related molecules that participate in regulating free iron levels (heme oxygenase I (HOI), iron-regulatory protein I (IRPI), and ferritin heavy chain (FTH)) and whether changes in the expression of these molecules are associated with differences in the expression of alpha-synuclein (ASN) which is thought to be a critical regulator in the pathogenesis of neurodegeneration. Using a well-established aging animal model, we demonstrate that the expression of HOI, FTH, and IRPI mRNAs is higher in the female hippocampus than that observed in male Fischer 344/NNiaHSD x Brown Norway/BiNia (F344BN) rats, regardless of age group. Consistent with these sexassociated alterations in iron-related regulators, the expression of ASN mRNA and protein in the female hippocampus was lower than that found in male rats. These results suggest a sex-dependent difference in regulating the expression of molecules involved in iron metabolism and neurodegeneration. A similar finding in humans, if present, may help to shed light on why sex may affect the incidence of neurodegenerative disorders