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Letters + Questions 

 

Letters from readers:

Thank you for the wonderful information regarding label ingredients. This information will make it easier for me to avoid wheat in my diet. Also, thank you for acknowledging that allergies can take many forms besides just anaphylatic shock, other respiratory problems or hives. I have been allergic to wheat for a long time and didn't realize it until had a blood test done. I have since removed wheat from my diet and it definitely confirms the diagnosis. I haven't felt this good in a long time! Thank you. Christine Goodwin.

 

 Questions:

Send answers/comments to editor@scienceinafrica.co.za 

  • I've read somewhere that the fresh smell one gets just after it's rained is due to ozone in the air. Is this true? And what causes the "ocean-fresh" smell of the sea? Also, why do you only smell it occasionally and not all the time?

  • Regarding NEPAD, I would briefly like to know what the 4 pillars of NEPAD are.

  • I was curious to see some very large birds taking off and flying around amongst the shells and low-flying bombers over the Tigris in the centre of Baghdad during the recent war in Iraq. Please could someone give me an I.D. on these?

  • I am a dentist and implantologist and have started making my own implants in my town. I buy material from Chennai that is the capital of my state Tamilnadu in India. Test results of the metal is ASTM Grade 2. I want to know if it is correct to use this for oral implants. I have heard that ASTM Grade 4 is better than 2. Is this correct?


 

Previous Month's Questions

Twins - what are the odds? Any answers?

Ankle joint manufacture in SA?

Unidentified crawling caterpillar - or new species? Any answers?

Which species of Cape Parrot are these?

Debate on food fortification

Commentary on World Summit on Sustainable Development

Sharknets

Chameleons indoors or outdoors

Our earliest ancestors and 'knuckle-walking'

Labradors with diabetes...how much insulin?

Innovation competitions and technikons

Mussels or not : seafood allergies

New developments in SA's AIDS battle

Chameleons disappearing?

Any new research in Heartwater?


Help identifying birds

Marlo and Maxine

Stan and StaciI am an exotic bird breeder located in Cincinnati, OH. I recently acquired two mature pairs of Cape parrots and would like some help in identifying which Capes I have. I know they are not the nominate robustus, but rather the fuscicollis or suahelicus. Can you help me identify them. I have attached photos of both pairs.
Thank you....Debbie Perrin E-mail: perrinda@worldnet.att.net

Reply:

Both pairs are definitely not Cape Parrots Poicephalus robustus. Instead I would strongly suggest that they are Grey-headed Parrots of which there
are 2 sub-species and I think yours are Poicephalus fuscicollis suahelicus.
It is difficult to tell P.f.suahelicus apart from P. fuscicollis fuscicollis and in fact no one has yet identified any true differences between them, but in my very limited experience there is an outward difference in bill-shape, with P. fuscicollis fuscicollis having a larger and more pronounced curvature. You might want to look at our species identification on 
the website of the Cape Parrot Working Group at www.cpwg.unp.ac.za

Sincerely, Louise Warburton, Research Centre for African Parrot Conservation, South Africa


Debate on food fortification

We would like to briefly respond to Mr Gary Klugman's reply (to our article) published in the Science in Africa journal (June 2002). We are somewhat surprised at the ongoing correspondence with Mr. Gary Klugman as we believe that we have already addressed the issues that he raised in our previous article published in Science in Africa in June 2002. Mr. Klugman is right when he says that there is a paucity of data on the actual absorption of electrolytic iron in maize porridge, although the specified levels are intended to offset the possible phytate-linked reduction in absorption. In addition, during the implementation phase, the Department of Health plans to conduct a baseline survey and monitor changes in nutritional status over time to assess this aspect as part of a comprehensive monitoring and evaluation component.

Jack Bagriansky
France Bégin
Venkatesh Mannar
Peter Ranum
The Micronutrient Initiative, 250, Albert Street, Ottawa, Ontario, Canada K1R 7Z1


 

THE JOHANNESBURG SUMMIT

It is with a sense of unreality that I view the ongoing flow of noble
statements about the upcoming summit. A case in point is the "WEHAB" article reproduced in your May 2002 issue, attributed to UN Secretary-General Kofi Annan.

No-one it seems has any intention whatsoever of raising the single key
issue: HUMAN OVERPOPULATION.

Instead, in an orgy of well-intentioned platitudes, the world prepares to
engage in yet another extravagant talk-shop where the haves will
diplomatically avoid genteel blackmail into increasing aid to the have-nots,
whereafter all 80,000 well-fed and rested delegates warmly pat each other on the back before jetting off to their next very important engagement.

And all the while the human species will happily conform to the biological
imperative of inexorable expansion to utilise the last of its available
resources.

Incredible! And I thought we had big brains?

Clearly the Johannesburg Summit will go down in history as 'Rio MINUS Ten'.

Sincerely
Peter Vos


 

Sharknets

QUESTION:
I often see documentaries on how large amounts marine fauna get caught and die in shark nets all over the world, and as far as I can see, this is
unnecessary. The problem with shark nets, is that they are not rigid, so animals get more entangled the more they twist and turn. Since the purpose of the nets is not to catch the sharks, but to provide a barrier (that doesn't go all the way to the ocean floor) to sharks to deter them from venturing close to the shore. A solution that could avoid tangling would be to use a more rigid barrier like a metal or plastic grate that could be suspended from the water surface like current nets are, and these grates could be interlinked to form a continuous barrier. 

This would much easier to maintain since you would not need teams of people to check the nets each day for entangled sharks and other fauna.
I cant see why such solutions have not yet been applied to this problem.


REPLY FROM EXPERT
Unfortunately, the reader has several incorrect assumptions in his letter of concern: 
(1) The only country other than South Africa (& that is only in KwaZulu-Natal) that has shark nets specifically designed to be used as a bather-protection device is Australia (New South Wales).

(2) The shark nets in each of these programmes historically catch approximately 1200 and 162 sharks per annum, respectively; far less than any target fishery for sharks (i.e. for human consumption).

(3) Shark nets are not designed to act as a barrier, they are merely a shark fishery designed to reduce the number of sharks close inshore and thereby reducing the chances of an encounter between sharks and humans. The 6m deep shark nets are set in approximately 10-12m water depth parallel to the coast and approximately 400m from the shore. Sharks can therefore swim through the gap between the nets and the seabed, between the adjacent nets themselves and between the shoreline and the nets. There is possibly a slight barrier effect, but approximately one third of the sharks caught are on the inside of the nets.

(4) Following the above explanation, the use of a more rigid device would not serve the same function. Although we are always striving to reduce the mortality of animals in the nets, any rigid structures in the sea off KwaZulu-Natal would soon get pummelled through the dynamic nature of this coastline (large surf). With present engineering constraints, it is unfortunately not possible to construct a rigid (or even semi-rigid) structure to extend from the beach, through the surf and back to the beach that would endure the constant beating of the surf. 

However, we appreciate the concern of the public regarding mortalities of our marine fauna and concur that efforts should be made to reduce any negative impact that the shark nets may have. The Natal Sharks Board has therefore initiated several projects to reduce impact, including (1) a 25% reduction in the total number of nets used (while maintaining the same degree of bather safety), (2) deploying sound producing devices (known as 'pingers') to warn dolphins of the presence of the nets, (3) removing the nets in advance of the annual winter 'sardine run' with its associated high predator activity and, more recently, (4) experimentation with the more selective alternative to nets that is known as 'drum-lines'. These are baited hooks attached to large buoys and are designed to catch large, potentially dangerous, sharks only. They have proved very effective as a bather protection device in Australia and are therefore the focus of research by the Natal Sharks Board.

I hope that this response has adequately answered the query from your reader. 

Sincerely, 

Dr. Vic Peddemors 
Chief Scientist 
Natal Sharks Board 


Chameleons indoors or outdoors

QUESTION FROM READER

We were recently given a "baby" chameleon (body length about 5cm).  I
am concerned about leaving it outside in our garden to live as I have
heard that Butcher birds etc often eat them.  I have a small
courtyard with a garden and have never seen any birds in there -
perhaps the Chameleon can live there?  In the meatime it sits in my
pot-plant in my kitchen - would this also be acceptable?

I am concerned that it will not be able to catch many flies for
eating - can we offer some dead flies?

Any other information would be highly appreciated.  thanks!

Sandy

ANSWER FROM EXPERT

Firstly, a chameleon with a 5 cm long body is not nesessarily a baby.
It could be a subadult or even adult dwarf chameleon.

You say you were given a chameleon. If this chameleon originates from
anywhere other than the region you live in, then it is not good
conservation practice to release it in your garden. I would never do
such a thing because it may have genetic implications. But I do
accept that it is in fact common practice for "naive" public to
introduce chameleons from all over into suburban gardens. And so I
can live with that - I just don't agree with it.

So let's say that you have a local chameleon - if you're living in
the Cape Town environs, chances are that you have a Cape Dwarf
Chameleon (Bradypodion pumilum). The chameleon will be much better
off in your court yard than indoors. It needs to eat quite frequently
(can do 20 small insects a day). No it will not eat dead flies. And
it needs moisture. If you're keeping it indoors for a while, spray
the plant it perches on with water. Chameleons drink water by licking
wet leaves (and not from a bowl). Yes, Butcher birds and cats may eat
your chameleon, but chances are that it will go unnoticed if you have
a well vegetated garden. Still better than dying of hunger "safely"
indoors...

Good luck  --  Marius Burger

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Our earliest Ancestors and 'knuckle walking'

Dear Dr Ackermann

Thank you for your recent article in Science In Africa wherein you distilled
a huge amount of confusing new data into a most useful form, comprehensible even to  fascinated laymen like myself. I really hope you can be cajoled into more such articles in issues to come.

Perhaps you might in a future article deal with knuckle-walking? This seems
to have been quite an issue earlier last year when Richmond and Strait of
George Washington University apparently found that Lucy and other afarensis (afarensi?) had the wrist spur, while A africanus did not. Nor apparently did A robustus or, significantly, the 3.3 myo Little Foot(?)

What of the real oldsters like Ardipithecus ramidus, Orrorin tugenensis and
A. kadabba? (Perhaps the remains are too fragmentary to tell?)

Is the wrist-spur still a hot issue, or has it perhaps petered out?

Sincerely
Peter Vos

Reply from Author:

Dear Peter Vos,

You are correct that the knuckle walking issue has caused a stir, and certainly the presence or absence of knuckle-walking morphology on
the distal radius (forearm bone) of O. tugenensis and A. ramidus
would go a long way towards settling the debate. This goes back to
the idea of what is primitive and what is derived - if we knew what
morphology the early ancestors of African apes and humans displayed,
it would be a whole lot easier interpreting the relationships among
the later hominids.   Richmond and Strait (2000) note that two of the
earliest hominid taxa  - A. anamensis and A. afarensis - both retain
specialized wrist morphology associated with knuckle-walking.  They
suggest that South African A. robustus and A. africanus have lost
this trait, and are subsequently more human-like.   Basically, this
implies that knuckle-walking was a shared derived characteristic of
the African ape and human clade, and that before bipedalism evolved
locomotion was a mixed-bag of terrestrial walking, arboreal climing,
and some suspension.  Therefore, the presence of
knuckle-walking traits in the early hominids is a kind of remnant
left over from their ancestors, even after they have transitioned to
bipedality.   I wish I could tell you more about knuckle walking in
the recent early hominids finds, but alas, the necessary skeletal
elements either aren't there, like in the case of Orrorin, or haven't
been fully analysed yet.  One thing is certain: this issue is far
from resolved.

Best wishes,
Dr Becky Ackermann


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Labrador with diabetes - how much insulin?

My 10 year old Labrador has diabetes...diagnosed three months ago. 
She has been on long acting insulin since then. Last week I brought her 
insulin down to 10u 2x per day...and this morning her glucose levels were 
way up high (fasting urine test). I gave her 12.5 u...Where do I go from 
here?  How dangerous is this level of glucose, and what symptoms do I look 
out for?

Reply from Author:

Dear Ms Craven, 

Did the vet tell you to reduce the insulin or had the glucose levels gone too low when you tested them prior to reducing the insulin? If the glucose levels have returned to normal again after increasing insulin to 12.5 u then remain with that dose. If not, then go back to the original dose suggested by the vet and, if this reduces glucose too much, reduce the amounts of insulin you give by smaller amounts (eg 12u then 11.5u until the glucose levels reach an acceptable level). 

Unfortunately you didn't give me the glucose levels you recorded but obvious symptoms of high glucose levels include excessive thirst (drinking lots of water all the time) and urinating all the time. Glucose levels that are too low could result in a diabetic coma so if your dog starts staggering and falling about, you must quickly give it a sugary drink. Glucose levels that are too high generally don't have any obvious effect but are highly dangerous because of the damage that long term high blood sugar levels do to the blood vessels. It is this damage that ultimately can lead to heart attacks, strokes, kidney disease etc. 

I hope that you will soon get your dog's glucose levels under control. 

Dr Sonia Wolfe-Coote 

For Dr Wolfe-Cootes article on Type 2 diabetes, ENTER HERE.

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Innovation and Entrepeneurs

It was very interesting to read your article "Are South African
scientists good innovators and entrepreneurs? (Link here for article)

It is noteworthy that only universities were visited, while Technikons are
closer to industry. Is it because the challenge for university staff (being
more theoretical) to become entrepreneurs are greater?

Regards
Jurie Groenewald

Reply from Author:

Dear Jurie,
Thank you for your response to the article.

I think technical entrepreneurship at universities, technikons, and the
population at  large in South Africa is lacking and needs to be improved.
We have chosen for now to focus on universities, because we see this to be
the source of the most significant technical breakthroughs. In future we may
also broaden our focus to include technikons.

The entrepreneurship workshops we held were also open to people outside the universities - as long as they registered with us first.

I hope this answers your question.

Kind regards,
Robert Zipplies
Catalyst Innovation Incubator (hosts of the Catalystii Innovation Competition)

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Missing Scientists

I am trying to find two friends whom I last saw in UK around 1969; they are Peter and Rachel Shelley. Peter had a PhD in Engineering from Imperial College, London and I believe his field was fluid mechanics. Rachel trained as a teacher but then did an MSc in Food Technology. They came to South Africa in about 1969, Dr Shelley to a lectureship and Rachel (née Schofield) to work as a scientist with an ice cream manufacturer. I hope you might publish my letter in some form and that someone who knows either of these two - or where they have worked or anything about them really - might get in touch with me. My name is Richard Sargent, I live in Somerset, England and my address is r.sargent@btinternet.com

Sincere thanks for your anticipated help,
Dick Sargent 

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Mussels or not?

I just read your article on the seafood allergy - very interesting. I find my ears, nose and throat itch like mad when i have shellfish with legs - crayfish, prawns crab and the like. Yet mussels and that sort of thing I'm fine with. Is there any thing I can do to get around this allergy as it was always there, so I know what it tastes like?

Thanks
Duncan Sutherland

Reply from author:


Dear Duncan

Sorry about your allergy, I can imagine how you feel, but 
unfortunately one can't do much about it. The best treatment at the 
moment is avoidance! If you accidentally eat some crustacean, you can 
take oral antihistamines, which help you with the symptoms. If you 
experience much stronger symptoms, this could happen if you continue 
to eat the particular crustacean, you could experience a so-called anaphylactic shock which could be fatal. So, be on the watch.

If you need any more written information, give me your postal address 
and I can send you a patient information sheet we have produced to 
give more info to the public.

All the best
Dr Andreas Lopata
Specialist Scientist (PhD)
Groote Schuur Hospital

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Chameleons disappearing?

Thank you for a most interesting web site. I enjoy all the articles because
they are well written and easily understood. I also find the links to other
web sites most interesting.

A point that I would like to raise is the disappearance of our chameleons. I
don't know if this would generate much interest in scientific circles but
over the last ten or twenty years the chameleons that were once fairly
common seem to have vanished and I have not seen one in over 3 years.

I live on the West Rand and often go for walks in the Kloofendal Nature
Reserve near me but see no chameleons. Previously we stayed in Bryanston and we would often come across chameleons in our garden but for a number of years prior to leaving there in 1996 I saw none.


Thanks once again.

Alistair Veitch

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New developments in SA's AIDS battle

One can not help but sympathize with President Thabo Mbeki over the HIV/AIDS crisis issue facing South Africa. To come to the conclusion that nothing can be done to stop AIDS, other than to give those people you preside over, either infected (positively diagnosed with HIV/AIDS) or possibly infected (rape victims, blood transfusion recipients etc), assorted drug medications for the rest of their lives must be harrowing to say the least, especially as the majority of infectees are young and female. It almost reads like some science fiction novel dreamed up by some author of the past (eg Dune): A people dependent on a substance other than required nutrients for life, controlled by those who supply the substance, basically enslaving them. As for the cost on the country - say R 100 per month per person per 10 million in population comes to one thousand million (billion) rands (R 1 000 000 000) every month. The suppliers / manufacturers would certainly smile over such returns from such a huge consumer market, and the power they get from the control of such. The president would certainly cry at such a scenario. At that rate our economy will more than likely be reduced to a miserable state regardless of who ever governs the country. In fact, I would consider abdicating and hand power over to those who seek it out, and let them try feed the rapidly increasing HIV population with the livelihood of the entire country. After all, it seems like a battle / war lost, so let the critics rule and reap their dubious rewards.

Dr David Ross, Cape Town

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New Research in Heartwater?

"We farm in Botswana and lose lots of stock to what we call in Afrikaans:
'Hart water'. Is there any new research on preventing this tick bite
inflicted illness for our area?"

E-mail: editor@scienceinafrica.co.za and we will forward your comments. 

Answer:

What you are talking about is referred to as Heartwater or Cowdriosis. It affects cattle, sheep & goats and some wild ruminants. It is caused by the rickettsia Cowdria ruminantium and transmitted by ticks of the genus Amblyomma. Heartwater is most severe in small ruminants but also causes great losses in exotic cattle that are more susceptible than indigenous breeds. Indigenous cattle are also affected when poor condition weakens the immune system or when animals are moved from an area free of heartwater to an endemic area. 

The disease develops after an infected tick has fed on a susceptible animal, and the nymphae and adult are the infective stages.

In Botswana, the tick Amblyomma hebraeum is found in the eastern parts of the country, making them the potential disease risk areas.

Apart from the cattle and small stock, various large & small game animals, hares & some ground-dwelling birds can also become infected with heartwater subclinically, meaning they don't show the clinical symptoms of the disease, but have Cowdria in their blood. As healthy carriers of the infection, these animals play an important role in maintenance of the infection in ticks. Because they cannot be dipped like cattle, these animals also serve as hosts on which ticks feed.

The disease has traditionally been controlled by the use of chemical acaricides to prevent and control transmission. Only one vaccine is commercially available against heartwater, a live vaccine produced from blood of sheep infected with the virulent Ball 3 stock of Cowdria. It has not been widely adopted because it requires a strict cold chain and can result in severe clinical reactions. Current research focuses on the development of safer and more effective inactivated vaccines. Oxytetracycline treatment is normally successful if administered early and is also used in a prophylactic manner during the peak of Amblyomma spp. season on very valuable and susceptible animals. This method, although not recommended by veterinarians, is widely used by commercial farmers in South Africa and by traditional farmers when they have to transport their cattle to endemic areas.

Hope information provided will help.

Motseki Hlatshwayo
University of the North
Qwa-Qwa Campus
Private Bag X13
Phuthadtijhaba
9866
E-mail: hlatshwayo@uniqwa.ac.za

Note: Information courtesy of Bruno Minjauw (Heartwater in Sub-Saharan Africa), DFID, AHP, FAO, ILRI ICTTD)

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Unidentified crawling caterpillar

Hi there,
I am convinced that I discovered a new species of "caterpillar" on my garden wall a few weeks ago. It definitely was something I've never seen before. It was redish brown in colour, about 4,5 - 5cm long and FLAT. More pointed at the head and tail and about 1cm wide across its middle. It had 3 or 4 pairs of legs at its top end and only 1 or 2 pairs at the rear end. What was MOST UNUSUAL was the little cluster of bristles which protruded from its rear end each time it moved forward, using these to push it forward. These little bristles were a much lighter shade, almost beige and went in & out its body as it moved forward. I did hold it briefly and there was no change in its attitude towards being handled, but soon replaced it where I'd found it & it disappeared into a dark crevice in my garden wall.

I have always had a fascination for any insects, spending much time studying each ones movements and antics, and found this particular chappie to be MOST DIFFERENT from anything I've ever seen in the past.
I would really appreciate it if you would be kind enough to send me an appropriate link to similar insects, so that I can try to locate it and read more about it if possible.
Many thanks,
Annie

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Twins - what are the odds?

I wonder if somebody could possibly assist me. I want to know what the chances of my having twins are. Here is a
brief history:

There is only one set of twins on my side of the family but many
generations ago. On my husband's side of the family it goes like this:

His grandmother had two sets of twins. His mother was one of the sets.
His mother then had a set of twins but one died before birth.

I would like to know how this is carried through the generations.

Laura

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Ankle joints in South Africa?

I had an amputation of my left leg under the knee in April 2000. I
want to know if any ankle joints are manufactured in the RSA. The prosthesis that I am using at the moment has a solid ankle joint. To change my prosthesis (the foot and ankle only) with a fancy ankle joint will cost about R 20 000. I want to know if any ankle joints are
in the process of being manufactured in South Africa. The imported prosthesis parts went up by 40% in November 2002. Please help us ordinary salary people to obtain these fancy prosthesis.
Regards

John

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