Your Accelerated Eyes

first_imgWhen a beam of light hits your eye, a chain of events is set off that is really quite amazing.  Kendall J. Blumer (Washington University School of Medicine) describes a little of it in the Jan. 1 issue of Nature.1  You don’t have to understand the following description; just be glad you don’t have to operate your retina in manual mode:Light streaming into the eye is detected by specialized neurons (photoreceptors) in the retina.  In response to light, a coordinated series of molecular events � the so-called phototransduction cascade � is triggered in these cells (Fig. 1).  Photons excite pigment-containing proteins called rhodopsins, which then switch on the protein transducin by loading it with the small molecule guanosine triphosphate (GTP).  When bound to GTP, transducin turns on a phosphodiesterase, an enzyme that breaks down cyclic guanosine monophosphate (cGMP � another small molecule).  High concentrations of cGMP open specialized ion channels in the outer cell membrane.  Thus, by reducing the concentration of cGMP, light changes the flow of ions across the membrane of photoreceptive neurons, producing an electrical signal that is necessary for communicating with the brain. (Emphasis added in quotes.)Now that’s just to turn the signal on.  When the light stops, it needs to be turned off quickly.  Normally, it would take too long for this process to reverse, but the retina has a standard procedure that takes care of it:But this presents a problem.  Photoreceptor cells can turn off in less than a second in response to a brief flash of light.  In contrast, the hydrolysis of GTP by transducin requires tens of seconds to complete, making it difficult to understand how such a mechanism could account for the rapid turn-off of photoreceptor cells.  To get around this problem, photoreceptor cells possess a protein called regulator of G-protein signalling 9 (RGS9) that accelerates transducin’s ability to hydrolyse GTP.Blumer describes what happens when a person has a defect in this accelerator protein.  It can take tens of seconds to adjust to a bright room when walking out of a theater.  It can take tens of seconds to see when driving into a dark tunnel.  And perhaps the worst of all (for Rose Bowl fans): “Moreover, people with this problem also suffer from difficulties in seeing certain moving objects (such as balls thrown during a sporting event).”    Having one such accelerator protein would be amazing enough, but now – the rest of the story: “RGS9 is one of nearly 30 such RGS proteins, which regulate signalling by hundreds of receptors coupled to transducin-like G proteins in cell networks of the nervous, cardiovascular, sensory and immune systems.”Kendall J. Blumer, “Vision: the need for speed,” Nature 427, 20 – 21 (01 January 2004); doi:10.1038/427020a.We need to know things like this to avoid taking our bodies for granted.  This one deserves a little pondering.  Do some simple experiments; see how quickly your eye adjusts to different light levels, and think about all those little protein machines knowing just what to do on cue.    Poor Charlie.  The eye as he knew it was enough to give him cold shudders.  In 1859, biochemistry was not even a science yet.  Charlie must be approaching absolute zero by now.  A book preceding The Origin of Species by about 2900 years, by a wiser man (Solomon), makes a lot more sense after reading the above description:  “The hearing ear and the seeing eye, The LORD has made them both” (Proverbs 20:12).(Visited 13 times, 1 visits today)FacebookTwitterPinterestSave分享0last_img read more

SA a stable democracy: Motlanthe

first_img5 March 2012 South Africa is politically and economically stable and investors should not be put off by debate about the country’s policies, which is natural in a fledgling democracy, says Deputy President Kgalema Motlanthe. Addressing the Ernst and Young Strategic Growth Forum Africa at the Westin Hotel in Cape Town on Friday, Motlanthe said it was “normal in a fledgling democracy that you will have a plethora of views, but we think we are doing very well in terms of national cohesion”. The country has been alive with debates on nationalisation, land reform and labour policies in recent months.Making space for opposing views “We come from a [past] where views were not tolerated, views were suppressed, so we have to open up space for people to ventilate their views in public,” Motlanthe said. “The trick is knowing which views influence policy processes and how policy is adopted,” he told business leaders and government officials from across the continent. South Africa is a constitutional democracy owing its allegiance to the Constitution. “Certainly as the executive we know we have to work in a co-operative fashion with the other two arms of the state [the judiciary and and legislature] and that we are held accountable to the Constitution,” Motlanthe said.Predictable investment environment South Africa remains an attractive investment destination – it has a predictable investment environment, is politically stable, has a stable banking system and offers many investment opportunities, the Deputy President said. The country also enjoys goodwill with neighbouring countries, which bodes well for investors looking to expand across Africa. Motlanthe said the country’s response to the 2008-09 global financial crisis – which brought the government, labour, civil society and business together in a national dialogue – was even adopted as a model by the International Labour Organisation (ILO).Cabinet ‘to consider amendments to labour laws’ Earlier last week, Motlanthe said the Cabinet would be considering amendments to the country’s Labour Relations Act over the coming months, as part of a range of measures to ensure that more jobs are created. Responding to a question in Parliament from leader of the opposition Lindiwe Mazibuko on Wednesday, Motlanthe added, however, that South Africa’s current labour legislation was flexible enough to allow for competition in the labour market. He said the improvement of the country’s tertiary colleges and training institutions, mooted in the recently released Green Paper on Post-School Further Education and Training, would accelerate efforts to build a capable labour force. Turning to what was being done to ensure that economic growth was being led by the private sector, Motlanthe said the private sector played a major role, but that there would also be a role for government to create an enabling environment for growth. Source: BuaNewslast_img read more

Feds Indict Reporter For ‘Anonymous’ Hyperlinking

first_imgYou now can get hauled into federal court in the United States for sharing a link in a chat room, apparently.  Barrett Brown, the journalist covering Anonymous-related activities for news outlets like The Guardian, was charged late Friday with 12 charges including linking, identity theft and fraud related to the Stratfor Global Intelligence hack.The indictment reads, “in that Brown transferred the hyperlink ‘http://wikisend.com/download/597646/stratfor_full_b.txt.gz’ from the Internet Relay Chat (IRC) channel called ‘#AnonOps’ to an IRC channel under Brown’s control called ‘#ProjectPM,’ said hyperlink provided access to data stolen from the company Stratfor Global Intelligence, to include in excess of 5,000 credit card account numbers.”Brown, who’s also writing a book about Anonymous, shared a link that thousands of people have shared before him. Brown is not charged with hacking into Stratfor, mind you, just linking. In fact, Brown’s involvement with Stratfor was more as a press laison than anything else.As someone who has been in and around Anonymous since 2008 as either as an activist or journalist, Brown’s indictment is downright terrifying. I’m not the only one that thinks so either.   Gawker’s Adrian Chen called this indictment “frightening because it seems to criminalize linking,” and he’s right. There is nothing in the language of the indictment that clarifies when it is okay to link to documents Anonymous puts publicly online.I’ve linked to “stolen information” countless times in articles I have written about Anonymous activities, and I know of other journalists and bloggers who have done the same. Besides articles, I’ve also retweeted Anonymous posts, posts that contained information that could be classified as stolen. There is nothing in Brown’s indictment that clarifies whether sharing links in this manner is illegal either.  “Worryingly, there is no specific information to indicate what, if anything, differentiates Brown’s behavior from that of any Twitter user simply retweeting the link to those files,” wrote Lorraine Murphy at The Daily Dot.    Who else retweeting dodgy information will be arrested?Immediately following news of Brown’s indictment, Internet activists, journalists and bloggers protested by tweeting the link that got Brown arrested, under #RightToLink.Asher Wolf, an online privacy advocate and creator of CryptoParty, led the charge with:It has been tweeted more than 230 times. Many #RightTo Link tweets argued that criminalizing hyperlinking and sharing hyperlinks infringes on free speech, but the hashtag failed to draw many First Amendment activists. As of Monday evening, #RightToLink had collected just under 1,600 individual mentions according to Topsy. One of my favorites tweets, as it encapsulates the fear, comes from VinceintheBay:“It’s a slippery slope. What’s next? No copy + pasting? No control + F? No right clicking? WTF?! #RightToLink #WarOnLinks”VinceintheBay’s tweet may seem hyperbolic, but there is the Richard O’Dwyer case to consider. The feds tried for two years to extradite O’Dwyer, a British citizen, for creating a site that linked to copyright-infringing material (a.k.a. Hollywood movies). Unlike Kim DotCom’s Megaupload, O’Dwyer’s TVShack never hosted actual content — it was a link aggregator like Reddit.O’Dwyer managed to avoid extradition last week by signing an agreement to pay $32,000 to “victims whose copyrights were infringed by TVShack,” a sum which represents the profit O’Dwyer made from ad sales on his site.  Will Brown be as “lucky”? Image courtesy of Barrett Brown’s YouTube channel Tags:#Anonymous The Dos and Don’ts of Brand Awareness Videos Guide to Performing Bulk Email Verification A Comprehensive Guide to a Content Auditcenter_img fruzsina eordogh Facebook is Becoming Less Personal and More Pro… Related Posts last_img read more

IAAF allows 21 more Russians to compete as neutrals

first_imgDon’t miss out on the latest news and information. Urgent reply from Philippine ‍football chief MOST READ LATEST STORIES Ferrari shows good pace, reliability in 1st week of F1 tests However, with just eight days before the European indoors start in Glasgow, Russia says they won’t have time to get British visas.“They’re all obviously happy to get neutral status and the theoretical chance to compete at the European championships, but for objective reasons our athletes have to turn it down,” head coach Yuri Borzakovsky said in a statement. “They just physically can’t manage to sort out all the organizational issues in such a short time.”FEATURED STORIESSPORTSPrivate companies step in to help SEA Games hostingSPORTSUrgent reply from Philippine ‍football chiefSPORTSPalace wants Cayetano’s PHISGOC Foundation probed over corruption chargesThe federation said this affects six athletes including Sokolova and decathlete Artyom Makarenko who meet the qualifying standards. Another 11 Russians who already had approval will compete led by two-time world high jump champion Maria Lasitskene.The IAAF said it had not been told of any visa issues before deciding the athletes’ cases and that Russian officials told its staff they wanted to send Makarenko to the championships as recently as Tuesday. FILE – In this file photo dated Thursday, June 6, 2013, Russia’s Yelena Sokolova competes in the women’s long jump event at the Golden Gala IAAF athletic meeting, in Rome’s Olympic stadium. (AP Photo/Andrew Medichini, FILE)MOSCOW, Russia—Russia’s officially neutral track and field team swelled in size as the IAAF approved 21 more athletes on Thursday to compete internationally — but Russia says it’s too late for next week’s European indoor championships.The IAAF ruled Yelena Sokolova, the 2012 Olympic silver medalist in long jump, can return to international competition for the first time since Russia’s team was banned in 2015 over widespread doping. Triple jumper Irina Gumenyuk has her approval extended from last season.ADVERTISEMENT US judge bars Trump’s health insurance rule for immigrants Private companies step in to help SEA Games hosting Grace Poe files bill to protect govt teachers from malicious accusationscenter_img SEA Games hosting troubles anger Duterte To get neutral status, Russian athletes have had to show they’re clean by providing information about their drug-testing history to an IAAF panel.The approvals are the first granted since the World Anti-Doping Agency started analyzing data from the Moscow laboratory last month. The IAAF said it has yet to receive any of the data.A total of 64 Russians have neutral status for 2019, of which 45 had the same status last year. A large number of cases have yet to be heard ahead of the world championships in Doha, which runs from Sept. 28 through Oct. 6.Seventy-three Russians had the status at some stage last season, according to Russian officials, who said they sent 192 applications for this season.Even with the neutral-status system in place, there have still been doping-related embarrassments for the IAAF and Russia. Of the six Russians who won world championship medals as neutrals in 2017, two have since been stripped of that status.ADVERTISEMENT They are race walk silver medalist Sergei Shirobokov, who traveled to a remote part of Kyrgyzstan to work with a banned coach, and the high jumper Daniil Lysenko, who is charged with failing to make himself available for three drug tests.Sports Related Videospowered by AdSparcRead Next ‘We are too hospitable,’ says Sotto amid SEA Games woes Oil plant explodes in Pampanga town PDEA chief backs Robredo in revealing ‘discoveries’ on drug war PH underwater hockey team aims to make waves in SEA Games PLAY LIST 02:42PH underwater hockey team aims to make waves in SEA Games01:44Philippines marks anniversary of massacre with calls for justice01:19Fire erupts in Barangay Tatalon in Quezon City01:07Trump talks impeachment while meeting NCAA athletes02:49World-class track facilities installed at NCC for SEA Games02:11Trump awards medals to Jon Voight, Alison Krauss View commentslast_img read more