The dominant Anopheles vectors of human malaria in the Asia-Pacific region: occurrence data, distribution maps and bionomic précis

<p>Abstract</p> <p>Background</p> <p>The final article in a series of three publications examining the global distribution of 41 dominant vector species (DVS) of malaria is presented here. The first publication examined the DVS from the Americas, with the second covering those species present in Africa, Europe and the Middle East. Here we discuss the 19 DVS of the Asian-Pacific region. This region experiences a high diversity of vector species, many occurring sympatrically, which, combined with the occurrence of a high number of species complexes and suspected species complexes, and behavioural plasticity of many of these major vectors, adds a level of entomological complexity not comparable elsewhere globally. To try and untangle the intricacy of the vectors of this region and to increase the effectiveness of vector control interventions, an understanding of the contemporary distribution of each species, combined with a synthesis of the current knowledge of their behaviour and ecology is needed.</p> <p>Results</p> <p>Expert opinion (EO) range maps, created with the most up-to-date expert knowledge of each DVS distribution, were combined with a contemporary database of occurrence data and a suite of open access, environmental and climatic variables. Using the Boosted Regression Tree (BRT) modelling method, distribution maps of each DVS were produced. The occurrence data were abstracted from the formal, published literature, plus other relevant sources, resulting in the collation of DVS occurrence at 10116 locations across 31 countries, of which 8853 were successfully geo-referenced and 7430 were resolved to spatial areas that could be included in the BRT model. A detailed summary of the information on the bionomics of each species and species complex is also presented.</p> <p>Conclusions</p> <p>This article concludes a project aimed to establish the contemporary global distribution of the DVS of malaria. The three articles produced are intended as a detailed reference for scientists continuing research into the aspects of taxonomy, biology and ecology relevant to species-specific vector control. This research is particularly relevant to help unravel the complicated taxonomic status, ecology and epidemiology of the vectors of the Asia-Pacific region. All the occurrence data, predictive maps and EO-shape files generated during the production of these publications will be made available in the public domain. We hope that this will encourage data sharing to improve future iterations of the distribution maps.</p

NUCLEAR MAGNETIC RESONANCE SPECTRA OF METHYLSILANES AND THEIR DERIVATIVES

Author Institution: University Chemical Laboratories; Mellon InstituteThe proton chemical shifts, the vicinal HH, directly-bound $^{29}SiH$ and $^{13}CH$, and some $^{29}SiCH$ coupling constants in more than 20 methylsilyl compounds are reported. These parameters, which have produced the empirical correlations given below, will be discussed with reference to those obtained from silyl and alkyl compounds. $CH_{3^{-}}$ and I- substituents contribute additively to $J_{SiH}$ in SiHXYZ. The $MH_{3}X$ coupling constants (M is C or Si) can be expressed as $J_{MH}^{4} (1+x)$, where the parameter x depends on X, and is approximately the same if M is C or Si. There is a fair correlation between increasing $J_{CH}$ and $J^{SiCH}_{gem}$ in $CH_{3}SiXYZ. CH_{3^{-}}, Br-$ and I- substituents contribute additively to $J_{CH} (CH_{3}SiXYZ)$ and $J^{HH}_{vic} (CH_{3}SiHXY)$, and the latter quantity can also be expressed, as for substituted ethanes, by an equation of the form $J^{HH}_{vic} = J^{0}(1-a\Delta E)$, where $\Delta E = E_{(X)}-E_{(H)}, E_{(X)}$ is the Huggins electronegativity of X, and $J^{0}$ is close to the observed coupling in monomethylsilane. Substitution by $CH_{3^{-}}$ or Br- changes the $\alpha(SiH)$ proton chemical shift additively, and similar effects on the $\beta(CH_{3})$ proton chemical shifts are observed with substitution by $CH_{3^{-}}, Cl-, Br-, or I-$. As in alkyl compounds, $CH_{3^{-}}$ and I- substitution shifts depend substantially on the other groups in the molecule, but Br- and (to a lesser extent) Cl- substitution shifts are fairly constant. The positive F- substitution shifts are particularly interesting. A fair correlation between increasing $\tau(CH_{3}MXYZ)$ and $J_{CH}(CH_{3}MXYZ)$, where M is C or Si, is observed