Geometry,vibrational frequencies,and ionization potentials for CO/Ni(100); explanation of the disappearance of the 5σ peak in pes

Using a cluster of 14 Ni atoms to model a Ni(100) surface, we used ab initio methods [generalized valence bond (GVB)] to study CO chemisorbed at the on-top site. Reported are the optimum geometry, vibrational frequencies, and ionization potentials. We propose a new explanation for the two lowest levels of free CO (5σ and 1π) reducing to one level of chemisorbed CO.     

Olefin-alkyl group exchange of B-alkyl-9-borabicyclo-[3.3.1]nonanes. Evidence for a dehydroboration-hydroboration process

B-Alkyl-9-borabicyclo[3.3.1]nonanes (9-BBN) undergo a rather facile olefin-alkyl group exchange process when refluxed with an olefin in tetrahydrofuran. Kinetic and competition studies support a dehydroboration-hydroboration process.     

Economic implications of poor access to antenatal care in rural and remote Western Australian Aboriginal communities: An individual sampling model of pregnancy

Background

Australian Aboriginal women attend antenatal care less frequently and experience poorer pregnancy outcomes than non-Aboriginal women. Improving access to antenatal care is recognised as a means to improve pregnancy outcomes for mother and baby.

Objective

To estimate the costs of inadequate antenatal care and provide baseline measurements and implications for policy that targets improving access to care in rural and remote Western Australian (WA) Aboriginal communities.

Methods

An individual sampling model of pregnancy was developed that simulated hypothetical women with pregnancy events and outcomes observed in the WA Aboriginal population. Weekly pregnancy events were modelled via logistic regression according to maternal characteristics, events during pregnancy and current gestation, with adequate and inadequate care (?4 and <4 antenatal visits) to reflect differences in outcomes reported in the literature. The pregnancy model simulated clinical management including antenatal visits, hospitalisations, and transfers to tertiary care.

Results

The mean cost of pregnancy was AUD$8985, with a large difference depending on access to antenatal care (AUD$7635 and AUD$10,216 for adequate and inadequate care respectively). The main difference in costs resulted from neonatal care (AUD$1021 vs AUD$3205 for adequate and inadequate care respectively). In a rural community with 150 births per year, up to AUD$123,082 may be spent to improve access to care at no extra cost to the total current expenditure (AUD$1,347,733).

Conclusions

The large difference in pregnancy costs between those receiving adequate and inadequate care demonstrates that additional expenditure on improving access to antenatal care may be cost-effective and should be further investigated.     

Role of Context in Risk-Based Reasoning

In this article we report the influence of contextual factors on mathematics and science teachers' reasoning in risk-based decision-making. We examine previous research that presents judgments of risk as being subjectively influenced by contextual factors and other research that explores the role of context in mathematical problem-solving. Our own approach has been to develop carefully designed software tools that support the user to empathize with a hypothetical person, Deborah, who suffers from a medical condition. The tools were used by a group of teachers who were asked to help Deborah decide whether to have an operation that could cure the condition but which carries particular risks. In order to make this decision, the teachers were required to model the risks of the operation and also the lifestyle decisions that Deborah might make. We trace the teachers' efforts to coordinate judgments of likelihood and impact. The data emphasize the sensitivity of reasoning to matters of context; we set out in detail the various ways in which the process was affected by context.     

MAKING LINKS BETWEEN ARITHMETIC AND ALGEBRAIC THINKING

In the Purposeful Algebraic Activity project we have designed and implemented a series of six spreadsheet based tasks for year 7 pupils aimed at developing early algebraic competence. Our data collection and analysis have been designed to collect evidence about specific features of both the spreadsheet environment and of task design, which influence the ways in which pupils engage with the notion of variable. In this paper we present a case study of one pair of pupils using data from the teaching programme and interviews. We use this case study to identify elements of the task design which have influenced the development of the pupils' thinking.     

Reliability of Speech-Language Pathologist and Otolaryngologist Ratings of Laryngeal Signs of Reflux in an Asymptomatic Population Using the Reflux Finding Score

OBJECTIVE: To determine inter- and intrajudge agreement in rating signs of laryngopharyngeal reflux (LPR) under "ideal" conditions: Experienced coworkers in a practice devoted to voice-disordered patients, raters trained in the items on a standardized scale, raters from both speech-language pathology (SLP) and otolaryngology, and raters of asymptomatic participants. STUDY DESIGN: Prospective study using a scale to rate videolaryngoscopic examinations. METHODS: Two SLPs and two otolaryngologists used the Reflux Finding Scale (RFS) to independently rate videotapes of endoscopic examinations for 30 participants asymptomatic of reflux. RESULTS: Thirteen (43%) were assigned a total score >7, indicative of LPR, by at least one rater. Intraclass correlation coefficients showed a significant lack of agreement in total scores provided by the otolaryngologists and by all raters combined. One otolaryngologist and the two SLPs demonstrated good interrater agreement in total scores. McNamar's statistic and Poisson regression modeling showed differences in rater agreement for many individual items. Repeated ratings of four participants showed no significant differences, indicating good intrarater reliability. CONCLUSIONS: Level of rater agreement regarding the presence and the severity of physical findings attributed to LPR within and between otolaryngologists and SLPs differed. Given the role each profession plays in the diagnosis and treatment of LPR and related voice disturbances, higher levels of interprofessional agreement are desired. Results support the need for greater consensus among professionals regarding the discreet features of physical findings associated with LPR, a fuller understanding of normal variants, and greater emphasis on interrater reliability when rating physical findings.     

Age-related changes in sensitivity to native phonotactics in Japanese infants

Japanese infants at the ages of 6, 12, and 18 months were tested on their ability to discriminate three nonsense words with different phonotactic status: canonical keetsu, noncanonical but possible keets, and noncanonical and impossible keet. The results showed that 12 and 18 months olds discriminate the keets/keetsu pair, but infants in all age groups fail to discriminate the keets/keet pair. Taken together with the findings in our previous study [Kajikawa et al., J. Acoust. Soc. Am. 120(4), 2278-2284 (2006)], these results suggest that Japanese infants develop the perceptual sensitivity for native phonotactics after 6 months of age, and that this sensitivity is limited to canonical patterns at this early developmental stage.     

Versatile Para-Substituted Pyridine Lanthanide Coordination Complexes Allow Late Stage Tailoring of Complex Function

A series of cationic and neutral p−Br and p−NO₂ pyridine substituted Eu(III) and Gd(III) coordination complexes serve as versatile synthetic intermediates. Nucleophilic aromatic substitution occurs readily at the para position under mild conditions, allowing C−N and C−C bond forming reactions to take place, permitting the introduction of azide, amino and alkynyl substituents. For Eu(III) complexes, this approach allows late stage tuning of absorption and emission spectral properties, exemplified by the lowering of the energy of an LMCT transition accompanied by a reduction in the Eu−N_py bond length. Additionally, these complexes provide direct access to the corresponding Eu(II) analogues. With the Gd(III) series, the nature of the p-substituent does not significantly change the EPR properties (linewidth, relaxation times), as required for their development as EPR spin probes that can be readily conjugated to biomolecules under mild conditions.     

The impact of impurities in synthetic peptides on the outcome of T-cell stimulation assays

Protein-spanning peptide pools have proven valuable as a screening tool for detecting T-lymphocyte responses against a wide range of proteins. We have used this approach in our search for T cells reactive to the onconeural protein HuD. We found positive responses in only 3 of 127 individuals; however, these were highly unusual in that the same class I HLA alleles and peptides were involved. These T-cell responses were not confirmed when peptides re-synthesized by the same manufacturer with similar and with higher purity levels were used. Our observations indicated that these T-cell responses were not directed against the designed HuD peptides. Here, we report on (i) comparisons of the peptide batches analyzed by matrix-assisted laser desorption/ionization Fourier transform mass spectrometry (MALDI-FTMS) that did--and did not--elicit T-cell responses and (ii) a detailed analysis of the various by-products of peptides, irrespective of T-cell assay outcome. We found numerous differences between the peptide batches, such as omissions of amino acids in the primary structure of the peptides. Furthermore, some batches revealed strong interactions with calcium ions or contained sulfated peptides. Our data reveal that different batches from the same peptide may contain artefacts that influence the outcome of HLA-restricted T-cell response assays.     

Formation and stability of mononuclear and dinuclear Eu(III) complexes and their catalytic reactivity toward cleavage of an RNA analog

The complex between Eu(III) and 1,7-diaza-4,10,13-trioxacyclopentadecane-N,N'-diacetic acid (L4) was characterized by pH potentiometric titration and 1H NMR spectroscopy. The conversion of the monomer to a dimeric complex is observed as the pH is increased from 7 to 10 in a reaction that releases one mol/HO- per dimer formed. The dimeric complex undergoes a further ionization with a pKa of 10.7. Kinetic parameters are reported for the cleavage of the simple phosphodiester 2-hydroxypropyl-4-nitrophenyl phosphate catalyzed by both the monomeric and the dimeric Eu(III) complexes. These data show that the monomer and dimer stabilize their bound reaction transition states with similar free energies of 7.1 and 7.6 kcal/mol, respectively. Clearly, a bridging hydroxide is not an optimal linker to promote cooperative catalysis between Eu(III) centers in macrocycles with multiple polyaminocarboxylate pendent groups.