Structural,compositional and mineralogical characterization of carbonatitic copper sulfide: Run of mine,concentrate and tailings

The aim of this study was to determine the structural, compositional, and mineralogical composition of carbonatitic copper sulfide concentrator plant streams. Three samples, each from a different stream(run of mine(ROM), concentrate, and tailings) of a copper concentrator were characterized using various techniques, including stereomicroscopy, X-ray fluorescence, X-ray diffraction, Fourier transform infrared(FTIR) spectroscopy, scanning electron microscopy(SEM) in conjunction with energy-dispersive X-ray spectroscopy(EDS), and optical microscopy. The results reveal that each stream possesses its own unique compositional features. Carbonate minerals associated with calcite and dolomite, followed by quartz, remain the major minerals in both the ROM and tails streams. In the ROM stream, chalcopyrite appears to occur as veins within the carbonatite-hosting ore body. Mineral phase mutation was discovered in the tails stream because magnetite formerly identified in the ROM as the primary iron oxide had evolved into hematite. This metamorphosis was likely promoted by the concentration process. The concentration process was effective, upgrading the chalcopyrite content from 2 wt% in the ROM stream to 58 wt% in the concentrate stream; it was accompanied by bornite(4 wt%), anilite(3 wt%), and digenite(2.5 wt%). In addition, the concentrate stream exhibited properties distinctive from those of the other streams. The FTIR analysis showed the existence of a sulfide group related to the chalcopyrite mineral. Free chalcopyrite grains were observed in the concentrate by SEM analysis, and their mineral presence was supported by the EDS analysis results. All characterization techniques corresponded well with each other regarding the structure, chemistry, and composition of the samples.     

Wolves in sheep’s clothing: three new cases of aggressive mimicry in Red Sea coral reef fishes

ABSTRACT

Here we document three cases of mimicry in coral reef fishes not previously reported in the literature involving two groupers (Epinephelus leucogrammicus and Plectropomus marisrubri) and a soapfish (Diploprion drachi) as mimics, and two wrasses (Larabicus quadrilineatus and Cheilinus quinquecinctus) and a blenny (Meiacanthus nigrolineatus) as models. All three cases are of aggressive mimicry, with a predatory species mimicking a harmless one, and in one of the cases, the mimicry is also Müllerian, where both the predator and harmless species are unpalatable.     

Diversity and dispersal history of the talitrids (Crustacea: Amphipoda: Talitridae) of Bermuda

Five taxa of talitrid amphipods were found in the archipelago of Bermuda, of which three were recorded there for the first time. Four of these are supralittoral wrack generalists: Platorchestia monodi BOLD:AAB3402, (a unique Molecular Operational Taxonomic Unit according to the Barcode Index Number system), a related species recognized by molecular methods, Platorchestia platensis BOLD:AAA2949, Mexorchestia carpenteri carpenteri BOLD:AAC1491 and Tethorchestia antillensis; and one a terrestrial leaf-litter generalist: Talitroides alluaudi. A key is provided to discriminate between the formally described talitrids of Bermuda. Dispersal mechanisms from the American continent to Bermuda were considered for all taxa based on species distributions along the North American Atlantic coast and also investigated by molecular methods, using genetic population differentiation and haplotype network analysis based on the barcode region of cytochrome c oxidase subunit I gene. For P. monodi BOLD:AAB3402 the genetic results suggest that some dispersal events occurred before human colonization of Bermuda but are equivocal about the source population and therefore the direction of dispersal. Some very recent synanthropic dispersal is possible with this species. For the other two species studied genetically, P. platensis BOLD:AAA2949 and M. c. carpenteri BOLD:AAC1491, the small population samples analysed support dispersal to Bermuda from the American mainland, before human occupation of Bermuda, although the available sample size was limited for these species. The available limited direct, non-genetic evidence supports synanthropic transport for Talitroides alluaudi. Platorchestia monodi BOLD:AAB3402 is found in the same wrack habitat as P. platensis BOLD:AAA2949 on Bermuda, apparently without interbreeding. No evidence was found that driftwood specialist talitrids had become established in Bermuda.     

Baronia brevicornis caterpillars build shelters to avoid predation

In at least 18 Lepidoptera families, caterpillars build shelters that mainly serve to regulate microclimate (humidity, temperature) and/or to avoid predation. We aimed to explore the function of the tubular structures built with the leaves of the host plant, Acacia cochliacantha Humboldt and Bonpland ex Willdenow (Fabaceae), by a lepidopteran endemic to Mexico, Baronia brevicornis Salvin. We experimentally evaluated whether tubular structure building behaviour is induced by high temperature or predator odour, and if shelters reduce or enhance predation of B. brevicornis caterpillars. We used Calosoma angulatum as predator. Our analyses showed that caterpillars did not make the tubular structures in response to high temperature. We also found no difference in predators’ visual recognition of sheltered versus unsheltered caterpillars. Caterpillars did not build shelters but they moved more often when exposed to predator odour. Unsheltered caterpillars were more frequently consumed when predators were allowed to interact with sheltered and unsheltered caterpillars. Hence, the tubular structures built by B. brevicornis are most likely a strategy for reducing predation, for example by C. angulatum.     

问答社区问句中多字词表达提取

基于互动问答社区问句中多字词表达和问句理解的关系,提出针对互动问答社区问句进行多字词表达抽取,并基于互动问答社区问句中多字词表达的特点,提出适用于互动问答社区的多字词表达提取方法.该方法在利用互信息和停用词表的方法从问句中抽取候选多字词表达的基础上,将候选多字词表达分为正确串、残缺串、冗余串和错误串4类,借助搜索引擎对查询串的优化和候选多字词表达在互联网上的检索结果,设计候选多字词表达校正方法,实现对多字词表达的提取.以新浪爱问知识人问题库中的问句进行实验,结果表明,多字词表达抽取的准确率、召回率和F值分别达到84%,52%和0.64,验证了该方法的有效性.     

Activation of stress signalling pathways enhances tolerance of fungi to chemical fungicides and antifungal proteins

Fungal disease is an increasing problem in both agriculture and human health. Treatment of human fungal disease involves the use of chemical fungicides, which generally target the integrity of the fungal plasma membrane or cell wall. Chemical fungicides used for the treatment of plant disease, have more diverse mechanisms of action including inhibition of sterol biosynthesis, microtubule assembly and the mitochondrial respiratory chain. However, these treatments have limitations, including toxicity and the emergence of resistance. This has led to increased interest in the use of antimicrobial peptides for the treatment of fungal disease in both plants and humans. Antimicrobial peptides are a diverse group of molecules with differing mechanisms of action, many of which remain poorly understood. Furthermore, it is becoming increasingly apparent that stress response pathways are involved in the tolerance of fungi to both chemical fungicides and antimicrobial peptides. These signalling pathways such as the cell wall integrity and high-osmolarity glycerol pathway are triggered by stimuli, such as cell wall instability, changes in osmolarity and production of reactive oxygen species. Here we review stress signalling induced by treatment of fungi with chemical fungicides and antifungal peptides. Study of these pathways gives insight into how these molecules exert their antifungal effect and also into the mechanisms used by fungi to tolerate sub-lethal treatment by these molecules. Inactivation of stress response pathways represents a potential method of increasing the efficacy of antifungal molecules.