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| Sex education, STIs and politicians make a toxic combination Should our response to the rising number of sexually transmitted infections (STIs) be a call for more ignorance, as one MP appears to believe?Woody Allen, in the movie Annie Hall, tells a joke about how two elderly (probably Jewish) women are at a Catskill Mountain resort, and one of 'em says, "Boy, the food at this place is really terrible." The other one says, "Yeah, I know; and such small portions." That's how I feel about sex education in Britain's schools. Over the bank holiday weekend, an MP, Stewart Jackson (Conservative, Peterborough) in response to media reports of a rise in the number of STIs (sexually transmitted infections) in teenagers, said on Twitter that the problem was too much sex education. He tweeted on 26 August:V disappointing news on STD rates in Pboro. No doubt our liberal friends will tell us we need MORE sex education – as it's worked so wellPredictably (although perhaps not to Mr Jackson), when it was further circulated on Twitter it led to a flurry of comments from people agreeing and – mainly – disagreeing with him. As far as I can tell, at first he chose not to respond but after some time he lashed out on Twitter, saying:Touched a raw nerve with shrill intolerant pro sex education Lefties who don't like debating the issues. Wonder why not?On 27 August he said, Re. Sex education Memo to sad tedious sex obsessed Leftie weirdos – do please tweeting me [sic] You're confusing me with someone who's interestedand thenLeft are simply unable to debate issues without personal abuse and vicious shrill denunciation. Important we keep them locked out of powerThe irony of tweeting an insult (even truly sad, tedious, sex-obsessed Leftie weirdos don't identify themselves as such) then complaining about insults led to a flurry of comment on Twitter, on blogs and even on the BBC. On Twitter everyone's tweets are public and accessible and it seems that all the tweets that had been directed at Mr Jackson – all that the bloggers could find – are entirely civil (certainly by parliamentary standards) and seek to debate the issues. It is therefore hard to see what he was objecting to when he made his complaint on which he enlarged in the Peterborough Evening Telegraph, where he also said that:"I wanted to engage in intelligent debate but was met with a barrage of crude, personal abuse. I am always keen to hear from my constituents but these people were generally not even from Peterborough and were only interested in making personal attacks."This repeated assertion had all the ingredients needed to infuriate people who use Twitter – rather like poking a wasps nest – who felt not only that they were right (cue cartoon), that he was failing to engage with them, that he falsely or unfairly accused them, but also that they had caught him in that alleged falsehood. None of these blogs, except perhaps one, was particularly rude, as opposed to critical, and there is no evidence that they were emailed or tweeted to him. There are some important issues behind all this.First, it is not clear whether the rise in reported STIs reflects a genuine rise in incidence or is an artefact of more widespread testing (leading to more true positives being picked up). This has been covered by Mark Easton at the BBC and by Dr Petra Boynton, and no doubt elsewhere, so I will not pursue that further here.Second, there is the question of whether we have too much sex education or too little. I would say we have too little and of poor quality. This is also the view of young people themselves, who report that sex education does not tell them what they need to know or does not reach them in time. There is surely merit in providing sex education before children are sexually active, and before the pubertal "giggle factor" and the "schoolyard fable factory" prevent information being readily accepted.There is international evidence that "school-based sex education improves awareness of risk and ways to reduce it. It increases the intention to practise safer sex and delays rather than hastens the onset of sexual activity". There is also evidence of this from the UK. Hell, sex education has even been reported to work in Peterborough! Other countries seem to do it better (sex education that is). For example in the Scandinavian countries and Holland, which can hardly be described as puritanical, and where sex education is delivered early and clearly (and where the media is more supportive of it), the rate of teenage conception (and teenage abortion) is much lower than in the UK. The age of first intercourse is also delayed relative to the UK. It seems that providing information equips boys to resist peer pressure and girls better to resist boy pressure. It also makes the use of effective contraception more likely when sexual activity does begin.I agree with Anne Widdecombe. I will repeat that. I agree with Anne Widdecombe – and Stuart Jackson – that there is a problem with the over-sexualisation of young people by our media more widely. I agree with them that this is unhealthy. No doubt it contributes to the earlier onset of sexual activity and also causes misery to girls (mainly) as they feel expected to conform to the sexualised body images portrayed in the media. Given that this is the society we have (and it is impossible to uninvent the internet, movies, teen magazines, TV, etc) we have two approaches to tackling this problem that could be used in combination. First, we can try to roll back the normalisation of portrayals of women as mainly or primarily sexual objects. We can for example regulate – or self-regulate – so that so-called family newspapers do not portray women in topless or sexual poses, and that such objectification and soft porn is marketed as such. So, for example, magazines like Zoo and Nuts should be available to adults and displayed and sold as such. I have supported cross-party campaigns on this led by the Fawcett Society and Object, but I am not certain whether Mr Jackson has done so. Second, we can equip young people for the world as it exists rather than as we would wish it to be. The curious thing about those who believe in Victorian values is that the Victorian age was a golden era for the sexual exploitation of women and the abuse of children.Evan Harrisguardian.co.uk © Guardian News & Media Limited 2010 | Use of this content is subject to our Terms & Conditions | More Feeds guardian.co.uk |
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Colour My World: Red parrot feathers resist bacterial degradation Why do parrots have such brightly colored feathers? There are lots of evolutionary reasons, but now you can add one more to the list: bright pigments resist bacterial degradationHave you ever noticed how many white bird species, such as most gulls and geese, have black wing feathers? This is because black and brown colours are the result of melanins that are incorporated into the feather structure while it is growing. Melanins strengthen feathers and reduce wear, especially in birds that fly long distances or that live in marine environments filled with abrasive sand and salt. But birds use their feathers for a variety of purposes. Probably the most familiar function is visual communication. The sex and age of an individual is often revealed by the intensity, quality, hue and pattern of its plumage colours. The brightest plumage colours are provided by carotenoid-based pigments, which are red, orange and yellow. But birds do not synthesize their own carotenoids; instead, these pigments are co-opted from their diet and are placed into growing feathers. Thus, carotenoid-based feather colours can provide visual information about the state of a particular individual's health and the quality of its diet. This is the reason that many captive flamingos are white while wild flamingos are a brilliant pink: they obtain carotenoid-based pigments from their diet of algae and invertebrates and place these pigments into their skin, feathers and even into the keratin sheath covering their beaks. The pinkest flamingos are those that consumed the best diet and are the healthiest. But among birds, the parrots are unique: their bright reds, oranges and yellows are not derived from dietary carotenoids. Unlike any other group of birds, parrots synthesize their own red, orange and yellow pigments, which were named "psittacofulvins" in honor of their avian creators [DOI: 10.1016/j.cbpc.2004.03.011]. Interestingly, these lipid-soluble pigments are found nowhere else; not in other birds, not in plants, nor even in plankton. In addition to their unique pigments, most parrots are monochromatic: males, females and even juvenile birds look very much the same and the brightness of their plumage doesn't vary, regardless of diet. Taken together, these factors suggest that their unique feather pigments serve more functions than just visual communication in parrots. This is where Edward H. Burtt, Jr., a professor in the Zoology Department at Ohio Wesleyan University in Delaware, Ohio, comes into the story. A few years ago, he noticed that a variety feather-consuming microbes, including Bacillus licheniformis, Bacillus pumilus and other Bacillus species, are present on feathers, particularly among birds that live in salty or humid habitats. So of course, he wanted to know why those bacteria were there. Dr Burtt's investigations showed these bacteria were eating feathers, and he also found that melanin-containing feathers are more resistant to bacterial degradation than those without melanins. Might the recently identified psittacofulvins serve a similar function in parrots, which primarily dwell in steamy tropical jungles? A tantalizing hint was provided by another researcher's observation that green feathers from Blue-crowned Parakeets, Aratinga aduticaudata, were unusually resistant to bacterial degradation [Grande et al]. To test the potential degradation-resistant properties of parrot feathers, Dr Burtt's team, which included several undergraduate honors students, first classified colourful flight feathers (rectrices and remiges) from 13 parrot species into six general colour categories: blue, green, red, yellow, black and white. The team placed differently-colored feathers into a bacterial medium containing Bacillus licheniformis, a bacteria that enzymatically degrades feathers. They measured the increased concentration of enzymatic by-products created as the bacteria broke down the feathers and compared this rate of accumulation between feathers of different colors (Figure 1):As you can see, they found that feather colour significantly affected the bacterial degradation rate: White feathers degraded more rapidly than black, blue, green and red feathers. This is consistent with their hypothesis that colourful psittacofulvin pigments reduce microbial damage to parrot feathers. Based on those data, it is reasonable to predict that green feathers -- which contain both psittacofulvins and melanins -- would be more resistant to bacterial degradation than feathers containing only melanins (blue, black) or only red psittacofulvins. But this is not what the team found. The reason lies in the biochemistry of these pigments: green feathers only contain yellow psittacofulvins -- not red. If you look closely at the above figure, you'll see that feathers containing yellow psittacofulvins degraded nearly as rapidly as did white feathers, which do not contain any pigments at all. Biochemical analysis of yellow psittacofulvin molecules found that they are formed by small carbon chains with few double-bonds, while red psittacofulvins are longer carbon chains with more double-bonds. In short, red psittacofulvin molecules are bigger than yellow psittacofulvins and have stronger bonds, so therefore, they should be more difficult for bacteria to break down. So the team tested this hypothesis by comparing the rate of feather degradation to the amount of red or yellow psittacofulvins that the feathers contained, and found a direct relationship (figure 2): So simply stated, the presence of psittacofulvins alone is not enough to resist bacterial damage: the feathers have to contain red psittacofulvins. Even though this isn't an earth-shaking finding, it is interesting to me, an evolutionary biologist studies and lives with parrots, and who finds avian color to be source of endless fascination. This sweet little study serves as a reminder that there can be (and probably are) several evolutionary functions for specific characters, all exerting their individual influences simultaneously. Even the tiniest of influences, such as biochemistry, can have some stunning evolutionary consequences, as exemplified by the featured photograph of a Green-winged Macaw, Ara chloroptera.Sources:Burtt, E., Schroeder, M., Smith, L., Sroka, J., & McGraw, K. (2010). Colourful parrot feathers resist bacterial degradation. Biology Letters DOI: 10.1098/rsbl.2010.0716McGraw, K.J., & Nogare, M.C. (2004). Carotenoid pigments and the selectivity of psittacofulvin-based coloration systems in parrots. Comparative Biochemistry and Physiology Part B: Biochemistry and Molecular Biology, 138 (3), 229-233 DOI: 10.1016/j.cbpc.2004.03.011Grande, J. M., Negro, J. J. & Torres, M. J. (2004). The evolution of bird plumage colouration: a role for feather-degrading bacteria? Ardeola 51 (2), 375–383.GrrlScientistguardian.co.uk © Guardian News & Media Limited 2010 | Use of this content is subject to our Terms & Conditions | More Feeds guardian.co.uk |
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