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Absorption spectrum of Rhodospirillum rubout pigment complexes in basic solvents. — The adsorption and aggregation of bacteriochlorophyll are studied in various polar solvents, at different concentrations. It is shown that 3 absorption bands exist in these conditions, duplicating 3 of the absorption bands found in vivo: the 772 nin, the 830 nm and the 890 nm-bands. The 800 nm-band cannot be formed in vitro. The relations between the respective concentrations of the 3 states of bacteriochlorophyll found In vitro are calculated and discussed. 相似文献
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Jacques Hartmann 《Ocean Development & International Law》2018,49(3):276-299
The United Nations Convention on the Law of the Sea (LOSC) permits state parties to establish an Exclusive Economic Zone (EEZ) 200 nautical miles from their coast. Coastal states have exclusive jurisdiction over resources within the EEZ, but navigational and other high seas freedoms continue to exist. A significant number of states have, however, enacted legislation that departs from the LOSC, interfering with the navigational rights and freedoms of other states. This article analzses this development with a specific focus on the Arctic. It investigates the powers of Arctic coastal states to regulate shipping in the EEZ and thereby navigation in the Arctic Ocean. It adds to the existing literature by providing an analysis of state practice, suggesting that despite uncertainty concerning the interpretation of the LOSC Article 234 and the right to exercise legislative jurisdiction over ice-covered waters, a not insignificant number of states have claimed jurisdiction in their own EEZ beyond the rights granted in the LOSC, and are therefore not in a position to object to extensive jurisdictional claims in the Arctic. 相似文献
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Agossa Fiacre R. Padonou Gil G. Fassinou Arsene Jacques Y. H. Odjo Esdras M. Akuoko Osei K. Salako Albert Koukpo Zinsou C. Nwangwu Udoka C. Akinro Bruno Sezonlin Michel Akogbeto Martin C. 《Malaria journal》2018,17(1):1-16
The emergence of mosquitoes that can avoid indoor-deployed interventions, such as treated bed nets and indoor residual spraying, threatens the mainstay of malaria control in Zambia. Furthermore, the requirement for high coverage of these tools poses operational challenges. Spatial repellents are being assessed to supplement these vector control tools, but limitations exist in the residual effect of the repellent and the need for external power or heat for diffusion of the volatiles. A semi-field evaluation of a novel controlled release spatial repellent device (CRD) was conducted in Macha, Zambia. These devices emanate metofluthrin with no need for external power. Devices were deployed in huts within the semi-field system (SFS). Female Anopheles gambiae sensu stricto released within the SFS were trapped overnight by light traps and collected by aspiration the next morning inside and outside of huts to determine the extent of mosquito repellency and the impact on host-seeking and survival. Experiments studied the impact of number of devices as well as the presence of hut occupants. The study was complemented with numerical methods based on computational fluid dynamics to simulate spatial distribution of metofluthrin. Presence of CRDs was associated with significant reductions in indoor counts of mosquitoes, regardless of whether huts were occupied or not. Repellency ranged from 15 to 60% compared to huts with no devices. Reducing the number of devices from 16 to 4 had little impact on repellency. When huts were occupied, indoor mosquito host-seeking was higher in the presence of CRDs, whilst survival was significantly reduced. This study demonstrated that deployment of as few as four CRDs within a hut was associated with reduced indoor mosquito densities. As would be expected, presence of occupants within huts, resulted in greater indoor catches (both with and without devices). The increased indoor mosquito host-seeking and mortality in huts when devices were present may be explained by the excito-repellency activity of metofluthrin. These semi-field experiments provide preliminary data on the utility of CRD spatial repellents to reduce indoor densities of An. gambiae mosquitoes. Studies will further investigate the impact of CRDs on mosquito behaviour as well as epidemiological protective efficacy. 相似文献
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Calibration and non‐orthogonality correction of three‐axis Hall sensors for the monitoring of MRI workers' exposure to static magnetic fields 下载免费PDF全文
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Redox‐triggered chiroptical switching activity of ruthenium(III)‐bis‐(β‐diketonato) complexes bearing a bipyridine‐helicene ligand 下载免费PDF全文
Nidal Saleh Nicolas Vanthuyne Jacques Bonvoisin Jochen Autschbach Monika Srebro‐Hooper Jeanne Crassous 《Chirality》2018,30(5):592-601
The charged, electroactive bipyridine‐helicene‐ruthenium(III) complex [ 4 ] . +,PF6? has been prepared from 3‐(2‐pyridyl)‐4‐aza[6]helicene and a Ru‐bis‐(β‐diketonato)‐bis‐acetonitrile precursor (β‐diketonato: 2,2,6,6‐tetramethyl‐3,5‐heptanedionato). Its chiroptical properties (electronic circular dichroism and optical rotation) were studied both experimentally and theoretically and suggest the presence of 2 diastereoisomers, namely (P,Δ)‐ and (P,Λ)‐[ 4 ] . +,PF6? (denoted jointly as (P,Δ*)‐[ 4 ] . +,PF6?) and their mirror‐images (M,Λ)‐ and (M,Δ)‐[ 4 ] . +,PF6? ((M,Δ*)‐[ 4 ] . +,PF6?). The electrochemical reduction of (P,Δ*)‐[ 4 ] . +,PF6? to neutral complex (P,Δ*)‐ 4 was performed and revealed strong changes in the UV‐vis and electronic circular dichroism spectra. A reversible redox‐triggered chiroptical switching process was then achieved. 相似文献
999.
Conifer‐feeding budworms emerge from overwintering sites as small larvae in early spring, several days before budburst, and mine old needles. These early‐emerging larvae suffer considerable mortality during this foraging period as they disperse in search of available, current‐year buds. Once buds flush, surviving budworms construct feeding shelters and must complete maturation before fresh host foliage senesces and lignifies later in the summer. Late‐developing larvae suffer greater mortality and survivors have lower fecundity when feeding on older foliage. Thus, there is a seasonal trade‐off in fitness associated with host synchrony: early‐emerging budworms have a greater risk of mortality during spring dispersal but gain better access to the most nutritious foliage, while, on the other hand, late‐emerging larvae incur a lower risk during the initial foraging period but must contend with rapidly diminishing resource quality at the end of the feeding period. We investigate the balance that results from these early‐season and late‐season synchrony fitness trade‐offs using the concept of the phenological window. Parameters associated with the variation in the phenological window are used to estimate generational fitness as a function of host‐plant synchrony. Because defoliation modifies these relationships, it is also included in the analysis. We show that fitness trade‐offs characterizing the phenological window result in a robust synchrony relationship between budworm and host plant over a wide geographic range in southern British Columbia, Canada. 相似文献
1000.
A subset of chemosensory genes differs between two populations of a specialized leaf beetle after host plant shift 下载免费PDF全文
Ding Wang Stefan Pentzold Maritta Kunert Marco Groth Wolfgang Brandt Jacques M. Pasteels Wilhelm Boland Antje Burse 《Ecology and evolution》2018,8(16):8055-8075
Due to its fundamental role in shaping host selection behavior, we have analyzed the chemosensory repertoire of Chrysomela lapponica. This specialized leaf beetle evolved distinct populations which shifted from the ancestral host plant, willow (Salix sp., Salicaceae), to birch (Betula rotundifolia, Betulaceae). We identified 114 chemosensory candidate genes in adult C. lapponica: 41 olfactory receptors (ORs), eight gustatory receptors, 17 ionotropic receptors, four sensory neuron membrane proteins, 32 odorant binding proteins (OBPs), and 12 chemosensory proteins (CSP) by RNA‐seq. Differential expression analyses in the antennae revealed significant upregulation of one minus‐C OBP (ClapOBP27) and one CSP (ClapCSP12) in the willow feeders. In contrast, one OR (ClapOR17), four minus‐C OBPs (ClapOBP02, 07, 13, 20), and one plus‐C OBP (ClapOBP32) were significantly upregulated in birch feeders. The differential expression pattern in the legs was more complex. To narrow down putative ligands acting as cues for host discrimination, the relative abundance and diversity of volatiles of the two host plant species were analyzed. In addition to salicylaldehyde (willow‐specific), both plant species differed mainly in their emission rate of terpenoids such as (E,E)‐α‐farnesene (high in willow) or 4,8‐dimethylnona‐1,3,7‐triene (high in birch). Qualitatively, the volatiles were similar between willow and birch leaves constituting an “olfactory bridge” for the beetles. Subsequent structural modeling of the three most differentially expressed OBPs and docking studies using 22 host volatiles indicated that ligands bind with varying affinity. We suggest that the evolution of particularly minus‐C OBPs and ORs in C. lapponica facilitated its host plant shift via chemosensation of the phytochemicals from birch as novel host plant. 相似文献