Cepheid Masses: FUSE Observations of S Mus

S Mus is the Cepheid with the hottest known companion. The large ultraviolet flux means that it is the only Cepheid companion for which the velocity amplitude could be measured with the echelle mode of the HST GHRS. Unfortunately, the high temperature is difficult to constrain at wavelengths longer than 1200 \AA because of the degeneracy between temperature and reddening. We have obtained a FUSE spectrum in order to improve the determination of the temperature of the companion. Two regions which are temperature sensitive near 16,000 K but relatively unaffected by H$_2$ absorption (940 \AA, and the Ly $\beta$ wings) have been identified. By comparing FUSE spectra of S Mus B with spectra of standard stars, we have determined a temperature of 17,000 $\pm$ 500 K. The resultant Cepheid mass is 6.0 $\pm$ 0.4 M$_\odot$. This mass is consistent with main sequence evolutionary tracks with a moderate amount of convective overshoot.Comment: accepted to Ap

Visualization of diffusion limited antimicrobial peptide attack on supported lipid membranes

Understanding the mechanism of action of antimicrobial peptides (AMP) is fundamental to the development and design of peptide based antimicrobials. Utilizing fast-scan atomic force microscopy (AFM) we detail the attack of an AMP on both prototypical prokaryotic (DOPC:DOPG) and eukaryotic (DOPC:DOPE) model lipid membranes on the nanoscale and in real time. Previously shown to have a favourable therapeutic index, we study Smp43, an AMP with a helical-hinge-helical topology isolated from the venom of the North African scorpion Scorpio maurus palmatus. We observe the dynamic formation of highly branched defects being supported by 2D diffusion models and further experimental data from liposome leakage assays and quartz crystal microbalance-dissipation (QCM-D) analysis, we propose that Smp43 disrupts these membranes via a common mechanism, which we have termed ‘diffusion limited disruption’ that encompasses elements of both the carpet model and the expanding pore mechanism

The dumortierite supergroup. I. A new nomenclature for the dumortierite and holtite groups

Although the distinction between magnesiodumortieite and dumortierite, i.e. Mg vs. Al dominance at the partially vacant octahedral Al1 site, had met current criteria of the IMA Commission on New Minerals, Nomenclature and Classification (CNMNC) for distinguishing mineral species, the distinction between holtite and dumortierite had not, since Al and Si are dominant over Ta and (Sb, As) at the Al1 and two Si sites, respectively, in both minerals. Recent studies have revealed extensive solid solution between Al, Ti, Ta and Nb at Al1 and between Si, As and Sb at the two Si sites or nearly coincident (As, Sb) sites in dumortierite and holtite, further blurring the distinction between the two minerals. This situation necessitated revision in the nomenclature of the dumortierite group. The newly constituted dumortierite supergroup, space group Pnma (no. 62), comprises two groups and six minerals, one of which is the first member of a potential third group, all isostructural with dumortierite. The supergroup, which has been approved by the CNMNC, is based on more specific end-member compositions for dumortierite and holtite, in which occupancy of the Al1 site is critical. (1) Dumortierite group, with Al1 = Al^(3+), Mg^(2+) and 〈, where 〈 denotes cation vacancy. Charge balance is provided by OH substitution for O at the O2, O7 and O10 sites. In addition to dumortierite, endmember composition AlAl_6Bsi_3O_(18), and magnesiodumortierite, endmember composition MgAl_6Bsi_3O_(17)(OH), plus three endmembers, “hydroxydumortierite”, 〈Al_6Bsi_3O_(15)(OH)_3 and two Mg-Ti analogues of dumortierite, (Mg_(0.5)Ti_(0.5))Al_6Bsi_3O_(18) and (Mg_(0.5)Ti_(0.5))Mg_2Al_4Bsi_3O_(16)(OH)_2, none of which correspond to mineral species. Three more hypothetical endmembers are derived by homovalent substitutions of Fe^(3+) for Al and Fe^(2+) for Mg. (2) Holtite group, with Al1 = Ta^(5+), Nb^(5+), Ti^(4+) and 〈. In contrast to the dumortierite group, vacancies serve not only to balance the extra charge introduced by the incorporation of pentavalent and quadrivalent cations for trivalent cations at Al1, but also to reduce repulsion between the highly charged cations. This group includes holtite, endmember composition (Ta_(0.6)〈_(0.4))Al_6Bsi_3O_(18), nioboholite (2012-68), endmember composition (Nb_(0.6)〈_(0.4_)Al_6Bsi_3O_(18), and titanoholtite (2012-69), endmember composition (Ti_(0.75)〈_(0.25))Al_6Bsi_3O_(18). (3) Szklaryite (2012-70) with Al1 = 〈 and an endmember formula 〈Al_6Bas^(3+)_ 3O_(15). Vacancies at Al1 are caused by loss of O at O2 and O7, which coordinate the Al1 with the Si sites, due to replacement of Si^(4+) by As^(3+) and Sb^(3+), and thus this mineral does not belong in either the dumortierite or the holtite group. Although szklaryite is distinguished by the mechanism introducing vacancies at the Al1 site, the primary criterion for identifying it is based on occupancy of the Si/As, Sb sites: (As^(3+) + Sb^(3+)) > Si^(4+) consistent with the dominant-valency rule. A Sb^(3+) analogue to szklaryite is possible

The dumortierite supergroup. II. Three new minerals from the Szklary pegmatite, SW Poland: Nioboholtite, (Nb_(0.6)〈_(0.4))Al_6Bsi_3O_(18), titanoholtite, (Ti_(0.75)〈_(0.25))Al_6Bsi_3O_(18), and szklaryite 〈Al_6Bas^(3+)_ 3O_(15)

Three new minerals in the dumortierite supergroup were discovered in the Szklary pegmatite, Lower Silesia, Poland. Nioboholtite, endmember (Nb_(0.6)〈_(0.4))Al_6B_3Si_3O_(18), and titanoholtite, endmember (Ti_(0.75)〈_(0.25))Al_6B_3Si_3O_(18), are new members of the holtite group, whereas szklaryite, endmember 〈Al_6Bas^(3+)_ 3O_(15), is the first representative of a potential new group. Nioboholtite occurs mostly as overgrowths not exceeding 10 μm in thickness on cores of holtite. Titanoholtite forms patches up to 10 μm across in the holtite cores and streaks up to 5 μm wide along boundaries between holtite cores and the nioboholtite rims. Szklaryite is found as a patch ∼2 μm in size in As- and Sb- bearing dumortierite enclosed in quartz. Titanoholtite crystallized almost simultaneously with holtite and other Ta-dominant minerals such as tantalite-(Mn) and stibiotantalite and before nioboholtite, which crystallized simultaneously with stibiocolumbite during decreasing Ta activity in the pegmatite melt. Szklaryite crystallized after nioboholtite during the final stage of the Szklary pegmatite formation. Optical properties could be obtained only from nioboholtite, which is creamy-white to brownish yellow or grey-yellow in hand specimen, translucent, with a white streak, biaxial (–), n_α = 1.740 – 1.747, n_β ∼ 1.76, n_γ ∼ 1.76, and Δ < 0.020. Electron microprobe analyses of nioboholtite, titanoholtite and szklaryite give, respectively, in wt.%: P_2O_5 0.26, 0.01, 0.68; Nb_2O_55.21, 0.67, 0.17; Ta_2O_5 0.66, 1.18, 0.00; SiO_2 18.68, 21.92, 12.78; TiO_2 0.11, 4.00, 0.30; B_2O_3 4.91, 4.64, 5.44; Al_2O_3 49.74, 50.02, 50.74; As_2O_3 5.92, 2.26, 16.02; Sb_2O_3 10.81, 11.48, 10.31; FeO 0.51, 0.13, 0.19; H_2O (calc.) 0.05, –, –, Sum 96.86, 96.34, 97.07, corresponding on the basis of O = 18–As–Sb to {(Nb_(0.26)Ta_(0.02)〈_(0.18)) (Al_(0.27)Fe_(0.05)Ti_(0.01))〈_(0.21)}_(Σ1.00)Al_6B_(0.92){Si_(2.03)P_(0.02)(Sb_(0.48)As_(0.39)Al_(0.07)}_(Σ3.00)(O_(17.09)OH_(0.04)〈_(0.87))_(Σ18.00), {(Ti_(0.32) Nb_(0.03)Ta_(0.03)〈_(0.10) )(Al_(0.3 5) Ti_(0.01) Fe_(0.01))〈_(0.15)}_(Σ1.00) Al_6 B_(0.86) {Si_(2.36) (Sb_(0.51) As_(0.14) )}_(Σ3.01)(O_(17.35)〈_(0.65))_(Σ18.00) and {〈_(0.53) (Al_(0.41) Ti_(0.02) Fe_(0.02))(Nb_(0.01)〈_(0.01) )}_(Σ1.00)Al_6 B_(1.01) {(As_(1.07) Sb_(0.47) Al_(0.03)) Si_(1.37) P_(0.06)}_(Σ3.00)(O_(16.46)〈_(1.54))_(Σ18.00). Electron backscattered diffraction indicates that the three minerals are presumably isostructural with dumortierite, that is, orthorhombic symmetry, space group Pnma (no. 62), and unit-cell parameters close to a = 4.7001, b = 11.828, c = 20.243 Å, with V = 1125.36 Å^3 and Z = 4; micro-Raman spectroscopy provided further confirmation of the structural relationship for nioboholtite and titanoholtite. The calculated density is 3.72 g/cm^3 for nioboholtite, 3.66 g/cm^3 for titanoholtite and 3.71 g/cm^3 for szklaryite. The strongest lines in X-ray powder diffraction patterns calculated from the cell parameters of dumortierite of Moore and Araki (1978) and the empirical formulae of nioboholtite, titanoholtite and szklaryite are [d, Å, I (hkl)]: 10.2125, 67, 46, 19 (011); 5.9140, 40, 47, 57 (020); 5.8610, 66, 78, 100 (013); 3.4582, 63, 63, 60 (122); 3.4439, 36, 36, 34 (104); 3.2305, 100, 100, 95 (123); 3.0675, 53, 53, 50 (105); 2.9305, 65, 59, 51 (026); 2.8945, 64, 65, 59 (132), respectively. The three minerals have been approved by the IMA CNMNC (IMA 2012-068, 069, 070) and were named for their relationship to holtite and occurrence in the Szklary pegmatite, respectively

Geochemical and microstructural characterisation of two species of cool-water bivalves (Fulvia tenuicostata and Soletellina biradiata) from Western Australia

The shells of two marine bivalve species (Fulvia tenuicostata and Soletellina biradiata) endemic to south Western Australia have been characterised using a combined crystallographic, spectroscopic and geochemical approach. Both species have been described previously as purely aragonitic; however, this study identified the presence of three phases, namely aragonite, calcite and Mg-calcite, using XRD analysis. Data obtained via confocal Raman spectroscopy, electron probe microanalysis and laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) show correlations between Mg • S and Mg • P in F. tenuicostata and between Sr • S and S • Ba in S. biradiata. The composition of the organic macromolecules that constitute the shell organic matrix (i.e. the soluble phosphorus-dominated and/or insoluble sulfur-dominated fraction) influences the incorporation of Mg, Sr and Ba into the crystal lattice. Ionic substitution, particularly Ca2+ by Mg2+ in calcite in F. tenuicostata, appears to have been promoted by the combination of both S- and P-dominated organic macromolecules. The elemental composition of these two marine bivalve shells is species specific and influenced by many factors, such as crystallographic structure, organic macromolecule composition and environmental setting. In order to reliably use bivalve shells as proxies for paleoenvironmental reconstructions, both the organic and inorganic crystalline material need to be characterised to account for all influencing factors and accurately describe the "vital effect"

WHO guidelines on fluid resuscitation in children: missing the FEAST data.

The World Health Organization recommendations on management of common childhood illnesses affect the lives of millions of children admitted to hospital worldwide. Its latest guidelines,1 released in May 2013, continue to recommend rapid fluid resuscitation for septic shock, even though the only large controlled trial of this treatment (Fluid Expansion as a Supportive Treatment (FEAST) found that it increased the risk of death in African children.2 A subsequent systematic review of bolus resuscitation in children with shock resulting from severe infection also did not support its use.3 Failure to take this evidence into account is not consistent with WHO’s commitment to systematically and transparently assess evidence using the GRADE (Grading of Recommendations Assessment, Development and Evaluation) process when producing guidelines and could endanger the lives of children

Evaluation of plastic and steel bins for protection of stored maize against Insect Infestation in Ghana: Poster

Maize is a staple food in Ghana where there is ever increasing demand for its use to also support poultry and livestock production. However, post-harvest loss of maize is high in Ghana. This study evaluated the effectiveness of plastic and steel bins as bulk storage structures to reduce maize post-harvest loss in Ejura, Ghana during the period from February 2016 to January 2017. Maize pre-disinfested with a solar biomass hybrid dryer was stored in the following treatments: i. a white 7-ton plastic bin filled with untreated maize, ii. agreen 7-ton plastic bin filled with untreated maize, iii.a 6-ton Kikapu steel bin filled with untreated maize, iv. six 50-kg polypropylene (PP) bags filled with maize treated with Betallic Super (80 g pirimiphos-methyl and 15 g permethrin per liter as an emulsifiable concentrate (EC)), and v. six 50-kg PP bags filled with untreated maize ascontrol. Moisture content, insect pests, insect damaged kernels (IDK), grain weight loss, aflatoxin and fumonisin levels data were collected monthly. Sitophilus zeamais, Tribolium castaneum, Cathartus quadricollis, and Cryptolestes ferrugineus were the dominant insect species collected from maize samples. At the end of 12 months of storage, % IDK in the control was &gt;17% while IDK values in the other treatments were &lt;3%. Mean grain weight losses of &lt;1% were recorded in the bin treatments. Mycotoxin levels in the control were above the allowable threshold of 15 ppb. Our data suggest that use of plastic and steel bins has potential to reduce post-harvest loss of maize during storage.Maize is a staple food in Ghana where there is ever increasing demand for its use to also support poultry and livestock production. However, post-harvest loss of maize is high in Ghana. This study evaluated the effectiveness of plastic and steel bins as bulk storage structures to reduce maize post-harvest loss in Ejura, Ghana during the period from February 2016 to January 2017. Maize pre-disinfested with a solar biomass hybrid dryer was stored in the following treatments: i. a white 7-ton plastic bin filled with untreated maize, ii. agreen 7-ton plastic bin filled with untreated maize, iii.a 6-ton Kikapu steel bin filled with untreated maize, iv. six 50-kg polypropylene (PP) bags filled with maize treated with Betallic Super (80 g pirimiphos-methyl and 15 g permethrin per liter as an emulsifiable concentrate (EC)), and v. six 50-kg PP bags filled with untreated maize ascontrol. Moisture content, insect pests, insect damaged kernels (IDK), grain weight loss, aflatoxin and fumonisin levels data were collected monthly. Sitophilus zeamais, Tribolium castaneum, Cathartus quadricollis, and Cryptolestes ferrugineus were the dominant insect species collected from maize samples. At the end of 12 months of storage, % IDK in the control was &gt;17% while IDK values in the other treatments were &lt;3%. Mean grain weight losses of &lt;1% were recorded in the bin treatments. Mycotoxin levels in the control were above the allowable threshold of 15 ppb. Our data suggest that use of plastic and steel bins has potential to reduce post-harvest loss of maize during storage

Fantasies of subjugation: a discourse theoretical account of British policy on the European Union

The decision by the UK government to hold a referendum on Britain’s membership of the European Union (EU) marks an important development in policy towards the EU. Policy changes of this kind must be understood in the historical and political context in which they occur. This includes the framing of the policy issues within public discourse. In the UK, policies are formed in a discursive environment which is overwhelmingly hostile towards the EU. Debates are structured by a predominantly Euroskeptic discourse which emphasizes the UK’s separation and heterogeneity from the rest of the EU. Drawing on the logics of critical explanation, this article examines the structure and affective power of Euroskeptic discourses which dictate the terms of the EU debate. It presents a case study of the recent EU treaty revision process, culminating in the Treaty of Lisbon. In so doing, it enables a deeper understanding of recent policy developments