Steric and electronic control of an ultrafast isomerization.

Synthetic control of the influence of steric and electronic factors on the ultrafast (picosecond) isomerization of penta-coordinate ruthenium dithietene complexes (Ru((CF3)2C2S2)(CO)(L)2, where L = a monodentate phosphine ligand) is reported. Seven new ruthenium dithietene complexes were prepared and characterized by single crystal X-ray diffraction. The complexes are all square pyramidal and differ only in the axial vs. equatorial coordination of the carbonyl ligand. Fourier Transform Infrared (FTIR) spectroscopy was used to study the ν(CO) bandshapes of the complexes in solution, and these reveal rapid exchange between two or three isomers of each complex. Isomerization is proposed to follow a Berry psuedorotation-like mechanism where a metastable, trigonal bipyramidal (TBP) intermediate is observed spectroscopically. Electronic tuning of the phosphine ligands L = PPh3, P((p-Me)Ph)3, ((p-Cl)Ph)3, at constant cone angle is found to have little effect on the kinetics or thermodynamic stabilities of the axial, equatorial and TBP isomers of the differently substituted complexes. Steric tuning of the phosphine ligands over a range of phosphine cone angles (135 < θ < 165°) has a profound impact on the isomerization process, and in the limit of greatest steric bulk, the axial isomer is not observable. Temperature dependence of the FTIR spectra was used to obtain the relative thermodynamic stabilities of the different isomers of each of the seven ruthenium dithietene complexes. This study details how ligand steric effects can be used to direct the solution state dynamics on the picosecond time scale of discrete isomers energetically separated by <2.2 kcal mol-1. This work provides the most detailed description to date of ultrafast isomerization in the ground states of transition metal complexes

What Do All These Numbers Mean? Data Visualization as an Innovative Methodology to Make Program Decisions

Background: There is a lack of consistent, comprehensible data collection and analysis methods for evaluating teacher preparation program’s coverage of required standards for accreditation. Of particular concern is the adequate coverage of standards and competencies that address the teaching of English learners and teachers of students from culturally and linguistically diverse backgrounds. Purpose: To graphically convey the findings of a faculty survey regarding English learner and multicultural content in teacher preparation coursework in order to inform them of inadequate coverage (and saturation) of those particular teaching standards and competencies. Setting: A small teacher preparation program in a Northern California public university that prepares elementary school teachers and special education teachers. Intervention: 10 full and part-time faculty members in a teacher preparation program that prepares elementary and special education teachers. Research Design: Congruency study, in which raw data from faculty survey responses were compared with rated program responses to teacher preparation standards by means of a relational database with graphing output capabilities. Data Collection: A survey instrument was designed and administered to all faculty members in the program. Findings: The resulting radar maps and other graphic outputs allowed faculty to clearly see where their course content aligned with the program accreditation response and where more coverage of that particular competency was necessary. Conclusions: The use of relational databases was a highly effective method for helping one teacher preparation program to visualize their progress towards meeting standards for teacher preparation in the area of student diversity and the teaching of English learners. Keywords: data visualization, program evaluation, teacher developmen

Prediction of Van Hove singularity systems in ternary borides

A computational search for stable structures among both $\alpha$ and $\beta$ phases of ternary ATB4 borides (A= Mg, Ca, Sr, Ba, Al, Ga, and Zn, T is 3d or 4d transition elements) has been performed. We found that $\alpha$-ATB4 compounds with A=Mg, Ca, Al, and T=V, Cr, Mn, Fe, Ni, and Co form a family of structurally stable or almost stable materials. These systems are metallic in non-magnetic states and characterized by the formation of the localized molecular-like state of 3d transition metal atom dimers, which leads to the appearance of numerous Van Hove singularities (VHS) in the electronic spectrum. The closeness of these VHS to the Fermi level can be easily tuned by electron doping. For the atoms in the middle of the 3d row (Cr, Mn, and Fe), these VHS led to magnetic instabilities and new magnetic ground states with a weakly metallic or semiconducting nature. The magnetic ground states in these systems appear as an analog of the spin glass state. Experimental attempts to produce MgFeB4 and associated challenges are discussed, and promising directions for further synthetic studies are formulated.Comment: 9 figure

ANALISIS KESULITAN SISWA DALAM MEMECAHKAN MASALAH MATEMATIKA PADA MATERI ARITMATIKA SOSIAL DI KELAS VII SMP NEGERI 2 BANDA ACEH TAHUN AJARAN 2013/2014

Banda Ace

Differential expression of CD10 in prostate cancer and its clinical implication

BACKGROUND: CD10 is a transmembrane metallo-endopeptidase that cleaves and inactivates a variety of peptide growth factors. Loss of CD10 expression is a common, early event in human prostate cancer; however, CD10 positive cancer cells frequently appear in lymph node metastasis. We hypothesize that prostate tumors expressing high levels of CD10 have a more aggressive biology with an early propensity towards lymph node metastasis. METHODS: Eighty-seven patients, 53 with and 34 without pathologically organ confined prostate cancer at the time of radical prostatectomy (RP), were used for the study. Fourteen patients with lymph node metastasis found at the time of surgery were identified and included in this study. Serial sections from available frozen tumor specimens in OCT were processed for CD10 immunohistochemistry. Cancer glands were graded for the presence and intensity of CD10 staining, and overall percentage of glands staining positive was estimated. Clinical characteristics including pre- and post-operative PSA and Gleason score were obtained. A similar study as a control for the statistical analysis was performed with CD13 staining. For statistical analysis, strong staining was defined as > 20% positivity based on the observed maximum separation of the cumulative distributions. RESULTS: CD10 expression significantly correlated with Gleason grade, tumor stage, and with pre-operative serum PSA. Seventy percent of RP specimens from patients with node metastasis showed strong staining for CD10, compared to 30% in the entire cohort (OR = 3.4, 95% CI: 1.08–10.75, P = 0.019). Increased staining for CD10 was associated with PSA recurrence after RP. CD13 staining did not correlate significantly with any of these same clinical parameters. CONCLUSION: These results suggest that the expression of CD10 by prostate cancer corresponds to a more aggressive phenotype with a higher malignant potential, described histologically by the Gleason score. CD10 offers potential clinical utility for stratifying prostate cancer to predict biological behavior of the tumor

Exploring attitudes to edgy urban destinations: the case of Deptford, London

The role of tourists and tourism in urban development is not fully understood. Research has focused on tourism districts within city centres, but less is known about tourism in peripheral, less affluent urban districts. These areas can appeal to visitors as edgy alternatives to mainstream destinations. This study establishes who is interested in visiting and why, and it explores the underlying rationale for negative attitudes. The aims are addressed by an in-depth analysis of Deptford in South East London. This area is a relatively deprived part of a world city, albeit one that has long been earmarked as London's next cool district. The study uses a mix of different sources to analyse the case. Responses to a New York Times article on Deptford are analysed and the attitudes of actual visitors and key stakeholders are explored. The discussion includes an examination of different interpretations and attitudes towards the notion of edginess. Edginess is deemed attractive by certain audiences; something linked to a reverence for working-class life in the arts. The study concludes that, whilst edginess is a noted characteristic, what people appreciate about Deptford is its ‘distinctive ordinariness’ – its contrast with more polished and contrived urban districts

LightBox: Full-stack Protected Stateful Middlebox at Lightning Speed

Running off-site software middleboxes at third-party service providers has been a popular practice. However, routing large volumes of raw traffic, which may carry sensitive information, to a remote site for processing raises severe security concerns. Prior solutions often abstract away important factors pertinent to real-world deployment. In particular, they overlook the significance of metadata protection and stateful processing. Unprotected traffic metadata like low-level headers, size and count, can be exploited to learn supposedly encrypted application contents. Meanwhile, tracking the states of 100,000s of flows concurrently is often indispensable in production-level middleboxes deployed at real networks. We present LightBox, the first system that can drive off-site middleboxes at near-native speed with stateful processing and the most comprehensive protection to date. Built upon commodity trusted hardware, Intel SGX, LightBox is the product of our systematic investigation of how to overcome the inherent limitations of secure enclaves using domain knowledge and customization. First, we introduce an elegant virtual network interface that allows convenient access to fully protected packets at line rate without leaving the enclave, as if from the trusted source network. Second, we provide complete flow state management for efficient stateful processing, by tailoring a set of data structures and algorithms optimized for the highly constrained enclave space. Extensive evaluations demonstrate that LightBox, with all security benefits, can achieve 10Gbps packet I/O, and that with case studies on three stateful middleboxes, it can operate at near-native speed.Comment: Accepted at ACM CCS 201