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941.
942.
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
943.
944.
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
945.
946.
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
947.
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
948.
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
949.
Marie Desgeorges André Mégarbané Caroline Guittard Soukeyna Carles Jacques Loiselet Jacques Demaille M. Claustres 《Human genetics》1997,100(2):279-283
Cystic fibrosis (CF) is thought to be rare among the Arab populations from the Middle East and little data have been reported
so far. We have studied a sample of 20 families living in Lebanon for several generations and who have at least one child
with CF. These families are mainly from the Maronite, Greek Catholic, Greek Orthodox, Shiite or Sunnite groups. We found a
50% rate of consanguineous marriage, independent of the community of origin. The distribution of CF genotypes was determined
through the screening of all exons of the CFTR (cystic fibrosis transmembrane conductance regulator) gene by the technique
of denaturing gradient gel electrophoresis combined with asymmetric amplification DNA sequencing. A total of ten different
mutations accounting for 87.5% of 32 unrelated CF alleles was identified, including two novel putative mutations (E672del
and IVS21-28G→A). Three mutations, ΔF508 (37.5%), W1282X (15.6%), and N1303K (9.4%) accounted for 62.5% of CF alleles. Interestingly,
in the Maronite group, 66.7% of the ΔF508 chromosomes were found to be associated with allele 7 of the IVS8(T)tract, contrasting
with the absolute linkage disequilibrium between European ΔF508 chromosomes and allele 9. During this study, two previously
undescribed polymorphisms (IVS14a + 17del5 and 2691T/C) were also identified.
Received: 2 January 1997 / Accepted: 16 March 1997 相似文献
950.
Luis M. Torres-Vila Jacques Stockel Roger Roehrich M. Carmen Rodríguez-Molina 《Entomologia Experimentalis et Applicata》1997,84(2):109-114
Dispersal and survival of Lobesia botrana Den. & Schiff. (Lepidoptera: Tortricidae) larvae in a simulated first generation and the relationship with their density on vine inflorescences were studied under field conditions. Artificial infestations with neonate larvae were conducted at densities of 5, 10, 15, 20 and 25 individuals per vine inflorescence. Larvae had a considerable dispersal capacity on the vine espalier and were able to reach several inflorescences around those artificially infested. Dispersal downwards (63.1%) was significantly more frequent than upwards (36.9%), probably because larvae move down the vine plant using silk threads. However, the fact that there was upwards dispersal provides evidence that larvae are capable of active locomotion upwards on the vine plant structure. Mean distances covered by larvae ranged between 10 and 30 cm, with a maximum as far as 45 cm. The longest displacements were not associated with the downward dispersal. The maximum distance covered by larvae was positively correlated with larval density. Mean distance and larval density were not correlated, but mean distances covered at high larval densities were significantly higher than at low densities. At higher larval densities, the proportion of larvae which established in the artificially infested inflorescences decreased whereas the proportion of dispersing individuals increased. However, as a result of the balance between establishment and dispersal, larval survival did not differ significantly among larval densities (26–44%). The results obtained suggest that larval dispersal must be taken into account when preimaginal stages are sampled to determine whether damage thresholds are reached in an integrated pest management program. 相似文献