असली उल्लू कौन
जैसे कोई राजनीतिक धन्धेबाज़ चुनाव बाद राष्ट्रजनों से विमुख होकर अपना मुंह फेर लेता है वैसे ही उलूक
तकरीबन एक बिंदु के गिर्द अपनी गर्दन को घुमा लेता है .अभी सामने देख रहा है अभी पीछे .
उलूक के मामले में वजह बड़ी सादी सी सामने आई है .उल्लू की सबकी सब,सारी , ग्रीवा धमनियां रीढ़ की
हड्डी के एक अंश कशुरूका (Vertebra)से होकर नहीं गुज़रती हैं .जो धमनियां कशेरूका से होकर जाती भी हैं
वहां वहां हड्डी में बनी नाली उस धमनी से 10गुना ज्यादा चौड़ी रहती है .ऐसे में जब उलूक एक केन्द्रीय बिंदु के
गिर्द अपनी गर्दन दाएं या बाएँ समान रूप से 270 अंश तक घुमा लेता है तब भी धमनियों के क्षतिग्रस्त होने का
कोई ख़तरा नहीं रहता है .
नेताओं में ऐसा अनुकूलन संभवतया चारा ,कोयला ,विकलांगों की बैसाखियाँ आदि खाने से पैदा हो गया है
.बहरसूरत विज्ञानियों को नेताओं और उल्लुओं को एक ही परिवेश में नियंत्रित परिश्थितियों में रख कर पता
लगाना चाहिए .इनमें से असली उल्लू कौन है .हमारा मानना है हमारे राजनीति धंधे बाज़ इस हुनर में
आदमियत का मान कम नहीं होने देंगे .विजय उन्हीं की होगी .दिग्विजयी वही साबित होंगें .
बहर हाल उल्लुओं के इस अनुकूलित हुनर की ओर लौटते हैं .
धमनियों के अवरुद्ध होकर दम घोटने की संभावनाओं को एक दम से खारिज करने के लिए एक और
अनुकूलन उल्लुओं में देखने को मिला है .जबड़े के नीचे की हड्डियों के नीचे की धमनियां चौड़ी होते होते एक
रेज़र्वायर (रक्ताशय ,जलाशय )में ही आ मिली है .जबकि मनुष्य की धमनियां दिल से निकलने के बाद संकरी
होती चली जाती हैं .ऐसे में दिमाग को राक्तापूर्ति निर्बाध होती रहती है भले धमनी कहीं से भी दब खप जाए
.इसी के चलते उल्लू अपना सिर (हेड )और आँखें एक बिंदु के चारों और आसानी से घुमाते रहतें हैं .
नेताओं स्सारी राजनीतिक धंधे बाजों में जन विमुख होने का गुण कब आया है यह अभी अनुमेय ही बना हुआ
है .
जॉन हापकिंस विश्वविद्यालय के साइंसदानों ने उन उल्लुओं पर आज़माइश की हैं जो स्वाभविक कारणों से
अपनी मौत मर गए हैं .
गर्दन के दोनों ओर की मुख्यधमनियों में जो दिमाग को रक्त ले जाती हैं साइंसदानों ने सुइयों के ज़रिये एक
रंगीन रंजक (डाई )पहुंचाई और इनके स्केन उतारे ताकि जीवित अवस्था में इन धमनियों में होने वाले रक्त
प्रवाह का जायजा लिया जा सके साथ ही अपने हाथ से ही इनकी गर्दन को 270 अंश नर्तन भी करवाया .
इस प्रकार इस तथ्य की पुष्टि भी हुई क्यों किसी कार एक्सीडेंट में व्हिप्लाश से आदमी की गर्दन टूट जाती है
या वह स्ट्रोक का शिकार होजाता है ग्रीवा धमनियों में रक्त प्रवाह के अवरुद्ध हो जाने से .जबकि उलूक ऐसा
मज़े से कर लेता है गर्दन और नेत्रों का दोनों और नर्तन रात में अपने शिकार की टोह लेते हुए .
मनुष्य और इतर प्राणियों के मामले में ग्रीवा धमनियां अति नाज़ुक होतीं हैं लेकिन उल्लुओं के मामले में एक
विशेष जैविक अनुकूलन ने उन्हें यह सुविधा प्रदान की है .
राजनीतिक धंधे बाजों पर अभी आश्माइशें होना बाकी हैं .नतीजों की प्रतीक्षा कीजिए .
Mystery of owls spinning their heads all the way around revealed
A team of scientists has solved the ever-perplexing question of how owls seem to be able to turn their heads all the way around, and they’ve picked up an international prize in the process.
The reason for the neck-turning ability is this: an owl’s neck arteries don’t go through every vertebra and, where the arteries do go through a vertebra, the canal in the bone is up to 10 times wider than the artery inside it, meaning the arteries are less likely to get damaged during rotation.
Even with the larger canals, there is still a possibility that the arteries could get pinched and stop the blood flow to the brain. But owls also have a way to get around this problem, the scientists discovered. The arteries that are at the base of an owl’s head widen and pool into reservoirs, whereas human arteries would narrow further away from the heart. “The reservoirs make for more blood flow, even if the arteries are pinched elsewhere,” explains NPR. This allows the owls to sustain the blood needed to move their heads and eyes, even as their head is turned.
The scientists at Johns Hopkins made their discovery by testing dead owls (which died of natural causes) and injecting dye into their necks to mimic blood flow, while moving their heads in real-time in a scanner.
The scientists won first prize in the National Science Foundation’s annual visualization challenge for their research and here’s the winning illustration. The research was also acknowledged in the journal Science on Feb. 1.
The study helps shed light on why humans can so easily damage their fragile neck vessels, while owls can turn their heads 270 degrees without injury.
“Until now, brain imaging specialists like me who deal with human injuries caused by trauma to arteries in the head and neck have always been puzzled as to why rapid, twisting head movements did not leave thousands of owls lying dead on the forest floor from stroke,” said study senior investigator Dr. Philippe Gailloud in a statement.
The team plans to test hawks next, to see if they share any of the same abilities that allow owls to turn their heads.
Birdwatch News Archive
Fabian de Kok-Mercado MA holds a Barred Owl. Photo courtesy of Johns Hopkins Medicine.
How do owls swivel their heads?
Birdwatch news teamPosted on: 02 Feb 2013
The mystery of how owls rotate their heads almost full circle – by as much as 270 degrees in either direction – has finally been solved.
In what may be the first experiment of its kind, medical illustrators and neurological imaging experts used angiography, CT scans and medical illustrations to examine the anatomy of 12 owls. The team, from Johns Hopkins Medicine in Baltimore, USA, and led by Fabian de Kok-Mercado MA found four major biological adaptations designed to prevent injury from rotational head movements.
The question has been how the bird doesn't throttle itself in the process. If humans did it, we'd cut the blood supply to our brains and pass out, and probably damage the delicate blood vessels in our necks and heads.
To solve the puzzle, the team studied the bone structure and complex vasculature in the heads and necks of Snowy, Barred and Great Horned Owls after their deaths from natural causes.
"Our in-depth study of owl anatomy resolves one of the many interesting neurovascular medical mysteries of how owls have adapted to handle extreme head rotations," says de Kok-Mercado, now a scientific illustrator and animator at the Howard Hughes Medical Institute.
Fellow researcher Philippe Gailloud MD added:"Until now, brain imaging specialists like me who deal with human injuries caused by trauma to arteries in the head and neck have always been puzzled as to why rapid, twisting head movements did not leave thousands of owls lying dead on the forest floor from stroke. The carotid and vertebral arteries in the neck of most animals – including owls and humans - are very fragile and highly susceptible to even minor tears of the vessel lining.”
“Our results show precisely what morphological adaptations are needed to handle such head gyrations and why humans are so vulnerable to osteopathic injury from chiropractic therapy. Extreme manipulations of the human head are really dangerous because we lack so many of the vessel-protecting features seen in owls.”
Read the full report in the journal Science.
In what may be the first experiment of its kind, medical illustrators and neurological imaging experts used angiography, CT scans and medical illustrations to examine the anatomy of 12 owls. The team, from Johns Hopkins Medicine in Baltimore, USA, and led by Fabian de Kok-Mercado MA found four major biological adaptations designed to prevent injury from rotational head movements.
The question has been how the bird doesn't throttle itself in the process. If humans did it, we'd cut the blood supply to our brains and pass out, and probably damage the delicate blood vessels in our necks and heads.
To solve the puzzle, the team studied the bone structure and complex vasculature in the heads and necks of Snowy, Barred and Great Horned Owls after their deaths from natural causes.
"Our in-depth study of owl anatomy resolves one of the many interesting neurovascular medical mysteries of how owls have adapted to handle extreme head rotations," says de Kok-Mercado, now a scientific illustrator and animator at the Howard Hughes Medical Institute.
Fellow researcher Philippe Gailloud MD added:"Until now, brain imaging specialists like me who deal with human injuries caused by trauma to arteries in the head and neck have always been puzzled as to why rapid, twisting head movements did not leave thousands of owls lying dead on the forest floor from stroke. The carotid and vertebral arteries in the neck of most animals – including owls and humans - are very fragile and highly susceptible to even minor tears of the vessel lining.”
“Our results show precisely what morphological adaptations are needed to handle such head gyrations and why humans are so vulnerable to osteopathic injury from chiropractic therapy. Extreme manipulations of the human head are really dangerous because we lack so many of the vessel-protecting features seen in owls.”
Read the full report in the journal Science.
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