Tag: 维也纳酒店里的鸡多少钱

Impact of ocean acidification and high solar radiation on productivity and species composition of a late summer phytoplankton community of the coastal Western Antarctic Peninsula

first_imgThe Western Antarctic Peninsula (WAP), one of the most productive regions of the Southern Ocean, is currently undergoing rapid environmental changes such as ocean acidification (OA) and increased daily irradiances from enhanced surface‐water stratification. To assess the potential for future biological CO2 sequestration of this region, we incubated a natural phytoplankton assemblage from Ryder Bay, WAP, under a range of pCO2 levels (180 μatm, 450 μatm, and 1000 μatm) combined with either moderate or high natural solar radiation (MSR: 124 μmol photons m−2 s−1 and HSR: 435 μmol photons m−2 s−1, respectively). The initial and final phytoplankton communities were numerically dominated by the prymnesiophyte Phaeocystis antarctica, with the single cells initially being predominant and solitary and colonial cells reaching similar high abundances by the end. Only when communities were grown under ambient pCO2 in conjunction with HSR did the small diatom Fragilariopsis pseudonana outcompete P. antarctica at the end of the experiment. Such positive light‐dependent growth response of the diatom was, however, dampened by OA. These changes in community composition were caused by an enhanced photosensitivity of diatoms, especially F. pseudonana, under OA and HSR, reducing thereby their competitiveness toward P. antarctica. Moreover, community primary production (PP) of all treatments yielded similar high rates at the start and the end of the experiment, but with the main contributors shifting from initially large to small cells toward the end. Even though community PP of Ryder Bay phytoplankton was insensitive to the changes in light and CO2 availability, the observed size‐dependent shift in productivity could, however, weaken the biological CO2 sequestration potential of this region in the future.last_img read more

Will contactless payment cards catch on in the United States?

first_img 7SHARESShareShareSharePrintMailGooglePinterestDiggRedditStumbleuponDeliciousBufferTumblr Contactless debit, credit and prepaid cards – payment cards that can be used by tapping a point of sale (POS) terminal or waving the card near the terminal – have been issued by major banks around the world since 2007.  Also referred to as “tap and pay” or “tap and go,” these cards feature an embedded NFC antenna and chip (different than the EMV chip) which allows the card to exchange payment credentials to an NFC enabled terminal with just a wave or a tap. They are touted for both speed and convenience mostly because no signature or PIN is needed.  In addition, transaction amounts using this capability are typically limited to $25 or $50, consistent with the waiving of the need for signature for mag stripe transactions for those amounts.Common in most countries around the worldContactless cards are very common in most developed countries. In the United Kingdom, for example, 88 million contactless cards have been issued and 187.7 million transactions were made in the month of April 2016 out of 1.1 billion global transactions. Overall, the total number of contactless transactions are up 185.9% from the previous year which means consumers like using the cards for their convenient, tap and go capability.In Australia, 66% of cardholders have a contactless card that allows them to tap and pay. Industry data reports that 53% of the Australian cardholders use their cards as tap and pay at least once a week.  In Canada, 10 percent of all domestic transactions are contactless now and said to be growing at the rate of 1% per month. continue reading »last_img read more

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