Palladium and platinum complexes of substituted 4-vinylcyclohexene

In recent years numerous complexes have been reported in which olefins were chelated to transition metals.Ever since the generally regarded first olefin complex, Zeise\u27s salt (32) KPt(C2H43, the interest in this field of organometallic chemistry has expanded to several families of olefinic ligands and metals like palladium(II), platinum(II) copper(I), silver(I), and more recently vanadium and titanium The nature of the bonding of olefins to metal atoms seemed to involved the interaction between pi electrons in the unsaturated molecule and the hybrid orbitals of the metal rather than a localized sigma bonds between the metal atom and a particular carbon atom. The metal was complexed to a hydrocarbon which possessed a surplus of electrons. The direct overlap of a sigma orbital of the metal anad the p-orbital of the carbon atom formed a sigma type bond. The ligand carbon atom donated a surplus bonding pi-p electrons to a vacant sigma orbital of the metal while at the same time the excess negative charge was released back to the olefin from from a pi-d orbital of the metal to an empty antibonding pi-p orbital of the carbon atom. Dewar (9) illustrated this point by molecular orbital diagram. (See figure B) [see PDF file for Formula] The metal to olefin bond consisted of two parts: (a) overlap of the pi electron density of the olefin with sigma type acceptor orbital on the metal atom and (b) a back-bonding resulting from the flow of electron density from filled metal dxy or other dπ - pπ hybrid orbitals into antibonding orbital on the carbon atom. A schematic diagram of platinum olefin complexes can be shown as: [see PDF file for Formula] It was the intention of this research to increase our understanding of these stable diolefin complexes. In particular, the occurrence of rearrangement upon complexation of certain ligands to most likely a more stable configuration posed an interesting project. They syntheses of diolefin complexes provided an establishment of good technique and verification of reported data. The program of study was concentrated on the complexation of cyclic diolefins with primarily palladium(II) and platinum(II) chloride

Hawaiian Plumerias

Reprint June 1972The plumeria is an important ornamental tree in Hawaii as well as in Florida, the West Indies, Central America, India, China, Indonesia, Australia, islands of the Pacific basin, and some other tropical regions. This booklet covers all aspects of plumeria cultivation in Hawaii

Introductory programming: a systematic literature review

As computing becomes a mainstream discipline embedded in the school curriculum and acts as an enabler for an increasing range of academic disciplines in higher education, the literature on introductory programming is growing. Although there have been several reviews that focus on specific aspects of introductory programming, there has been no broad overview of the literature exploring recent trends across the breadth of introductory programming. This paper is the report of an ITiCSE working group that conducted a systematic review in order to gain an overview of the introductory programming literature. Partitioning the literature into papers addressing the student, teaching, the curriculum, and assessment, we explore trends, highlight advances in knowledge over the past 15 years, and indicate possible directions for future research

Student Employment: Linking College and the Workplace

The focus of National Student Employment Association (formerly the National Association of Student Employment Administrators, or NASEA) publications has always been on students in transition. From the freshman moving from high school to higher education, to the senior attempting the transition to professional employment and financial independence, we always have explored how students can better accomplish these linking experiences. Student employment is a hybrid, serving as a bridge between work and school, and ultimately, a link between school and full-time work. Student employment links elements of financial aid, career development, academic learning, experiential education, and personal development. Student employment, in all of these ways, is a bridge, moving the student from point A to point B. Because of this variety, any publication on student employment must necessarily speak to diverse themes. We have organized this publication in four sections: an introduction followed by three themed sections.https://digitalcommons.brockport.edu/bookshelf/1000/thumbnail.jp

Finishing the euchromatic sequence of the human genome

The sequence of the human genome encodes the genetic instructions for human physiology, as well as rich information about human evolution. In 2001, the International Human Genome Sequencing Consortium reported a draft sequence of the euchromatic portion of the human genome. Since then, the international collaboration has worked to convert this draft into a genome sequence with high accuracy and nearly complete coverage. Here, we report the result of this finishing process. The current genome sequence (Build 35) contains 2.85 billion nucleotides interrupted by only 341 gaps. It covers ∼99% of the euchromatic genome and is accurate to an error rate of ∼1 event per 100,000 bases. Many of the remaining euchromatic gaps are associated with segmental duplications and will require focused work with new methods. The near-complete sequence, the first for a vertebrate, greatly improves the precision of biological analyses of the human genome including studies of gene number, birth and death. Notably, the human enome seems to encode only 20,000-25,000 protein-coding genes. The genome sequence reported here should serve as a firm foundation for biomedical research in the decades ahead

Developmental delays and dental caries in low-income preschoolers in the USA: a pilot cross-sectional study and preliminary explanatory model

Abstract Background Anecdotal evidence suggests that low-income preschoolers with developmental delays are at increased risk for dental caries and poor oral health, but there are no published studies based on empirical data. The purpose of this pilot study was two-fold: to examine the relationship between developmental delays and dental caries in low-income preschoolers and to present a preliminary explanatory model on the determinants of caries for enrollees in Head Start, a U.S. school readiness program for low-income preschool-aged children. Methods Data were collected on preschoolers ages 3–5 years at two Head Start centers in Washington, USA (N = 115). The predictor variable was developmental delay status (no/yes). The outcome variable was the prevalence of decayed, missing, and filled surfaces (dmfs) on primary teeth. We used multiple variable Poisson regression models to test the hypothesis that within a population of low-income preschoolers, those with developmental delays would have increased dmfs prevalence than those without developmental delays. Results Seventeen percent of preschoolers had a developmental delay and 51.3% of preschoolers had ≥1 dmfs. Preschoolers with developmental delays had a dmfs prevalence ratio that was 1.26 times as high as preschoolers without developmental delays (95% CI: 1.01, 1.58; P < .04). Other factors associated with increased dmfs prevalence ratios included: not having a dental home (P = .01); low caregiver education (P < .001); and living in a non-fluoridated community (P < .001). Conclusions Our pilot data suggest that developmental delays among low-income preschoolers are associated with increased primary tooth dmfs. Additional research is needed to further examine this relationship. Future interventions and policies should focus on caries prevention strategies within settings like Head Start classrooms that serve low-income preschool-aged children with additional targeted home- and community-based interventions for those with developmental delays

The Performance of Adaptive Routers on Worst Case Permutations

. Chaotic routing [4, 13, 14] is a randomized, nonminimal adaptive routing algorithm for multicomputers. An adaptive routing algorithm is one in which the path a packet takes from its source to its destination may depend on other packets it encounters. Such algorithms potentially avoid network bottlenecks by routing packets around &quot;hot spots.&quot; Minimal adaptive routing algorithms have the additional advantage that the path each packet takes is a shortest one. Chinn, Leighton, and Tompa [6] provide a lower bound for permutation routing problems on the n \Theta n mesh for a large class of deterministic minimal adaptive algorithms. Specifically, they prove that for any such routing algorithm, there exists a permutation that requires\Omega (n 2 =k 2 ) steps to route all the packets in the permutation, where k is the number of packets a node can contain. We present experimental results showing the performance of the Chaos router on permutations for which a deterministic m..

Palladium and platinum complexes of substituted 4-vinylcyclohexene

In recent years numerous complexes have been reported in which olefins were chelated to transition metals.Ever since the generally regarded first olefin complex, Zeise\u27s salt (32) KPt(C2H43, the interest in this field of organometallic chemistry has expanded to several families of olefinic ligands and metals like palladium(II), platinum(II) copper(I), silver(I), and more recently vanadium and titanium The nature of the bonding of olefins to metal atoms seemed to involved the interaction between pi electrons in the unsaturated molecule and the hybrid orbitals of the metal rather than a localized sigma bonds between the metal atom and a particular carbon atom. The metal was complexed to a hydrocarbon which possessed a surplus of electrons. The direct overlap of a sigma orbital of the metal anad the p-orbital of the carbon atom formed a sigma type bond. The ligand carbon atom donated a surplus bonding pi-p electrons to a vacant sigma orbital of the metal while at the same time the excess negative charge was released back to the olefin from from a pi-d orbital of the metal to an empty antibonding pi-p orbital of the carbon atom. Dewar (9) illustrated this point by molecular orbital diagram. (See figure B) [see PDF file for Formula] The metal to olefin bond consisted of two parts: (a) overlap of the pi electron density of the olefin with sigma type acceptor orbital on the metal atom and (b) a back-bonding resulting from the flow of electron density from filled metal dxy or other dπ - pπ hybrid orbitals into antibonding orbital on the carbon atom. A schematic diagram of platinum olefin complexes can be shown as: [see PDF file for Formula] It was the intention of this research to increase our understanding of these stable diolefin complexes. In particular, the occurrence of rearrangement upon complexation of certain ligands to most likely a more stable configuration posed an interesting project. They syntheses of diolefin complexes provided an establishment of good technique and verification of reported data. The program of study was concentrated on the complexation of cyclic diolefins with primarily palladium(II) and platinum(II) chloride