Showing posts with label a. Show all posts
Showing posts with label a. Show all posts
Wednesday, March 18, 2015
How to Build a Skiff Wood Boat Plans
How to Build a Skiff - Wood Boat Plans
The following is a description of an easily constructed 12-ft. skiff, suitable for rowing and paddling.This is the type used by many duck hunters, as it may be easily pushed through marshes. It is constructed of 3/4-in. dressed pine, or cypress.
The Skiff is Especially Constructed for Use in Shallow Water and Marshes by Duck Hunters, but with the Addition of a Keel It Makes a Good Craft for Almost Any Water as a Rowboat
The sides consist of planks, 14 in. wide, but 12-in. planks may be used, the length being 12 ft. 4 in. Two stem pieces are constructed as shown in Fig. 1, and the plank ends are fastened to them with screws. Nail a crosspiece on the plank edges in the exact center, so as to space the planks 34 in. apart, as shown in Fig. 2; then turn it over and nail another crosspiece in the center of the planks for width, and make the spacing of the other edges 40 in. Plane the lower edges so that, in placing a board across them, the surfaces will be level. The floor boards are 6 in. wide and fastened on crosswise, being careful to apply plenty of red lead between all joints and using galvanized nails, 2 in. long.
(Fig. 3)
A deck, 18 in. long, is fastened on each end, as shown in Fig. 3. It is made of strips fastened to a crosspiece. The seats, or thwarts, consist of 10-in. boards, and are placed on short strips fastened to the side planks about 5 in. from the bottom. The oarlocks are held in a wedge-shaped piece of wood, having a piece of gas pipe in them for a bushing, the whole being fastened at the upper edge of the side planks with screws, as shown in Fig. 4. The location of these must be determined by the builder.
(Fig. 4)
Some calking may be required between the bottom, or floor, boards, if they are not nailed tightly against one another. The calking material may be loosely woven cotton cord, which is well forced into the seams. The first coat of paint should be of red lead mixed with raw linseed oil, and when dry any color may be applied for the second coat.
While, for use in shallow water, these boats are not built with a keel, one can be attached to prevent the boat from "sliding off" in a side wind or when turning around. When one is attached, it should be 3/4 in. thick, 3 in. wide, and about 8 ft. long.
—Contributed by B. Francis Dashiell, Baltimore, Md.
THE BOY MECHANIC - BOOK 2
1000 THINGS FOR BOYS TO DO
HOW TO CONSTRUCT DEVICES FOR WINTER SPORTS, MOTION-PICTURE CAMERA, INDOOR GAMES, REED FURNITURE, ELECTRICAL NOVELTIES, BOATS, FISHING RODS, CAMPS AND CAMP APPLIANCES, KITES AND GLIDERS, PUSHMOBILES, ROLLER COASTER, FERRIS WHEEL
AND
HUNDREDS OF OTHER THINGS WHICH DELIGHT EVERY BOY WITH 995 ILLUSTRATIONS
PUBLISHED 1915, BY H. H. WINDSOR CHICAGO
POPULAR MECHANICS CO. PUBLISHERS
Pass the clams please A strategy for object retrieval in the octopus
I recently blogged about a line of research on octopus reaching movements, but I left out an important study for times sake. I promised to cover it promptly, and so Im making good on that promise here. To recap:
It has been shown that reaching movements by octopuses are controlled by the nervous system of the arms relatively autonomously from the central nervous system; that is, a severed arm can complete these movements on its own, given the proper stimulation of the base of the nerve cord of the arm. This is all well and good, as the movements being studied were rather simple, involving the extension of an arm. This reaching movement was found to consist of a propagating wave of muscle activity down the arm, a solution to the control of such a flexible appendage that greatly reduces the amount of neural computation that is needed to make such a movement.)
The study Ill look at today is Octopuses Use a Human-like Strategy to Control Precise Point-to-Point Arm Movements by Sumbre et al (2006). In it, the authors study a more complicated movement: retrieval of an object using a single arm. This is a problem of interest to neuroscientists and roboticists, because understanding how the octopus generates controlled, precise movement using an appendage with so many possible movements might give us some insight into the optimal solution of this problem. This could help reveal general rules of efficiency in neural programming.
Beginning (as is advisable) at the beginning, the authors videotaped reaching movements in O. vulgaris that were elicited by touching a piece of food to the animals outstretched arm. Their observations revealed that octopuses create joints in their arm during this movement, around which they move stiffened segments of the arm much the same way that animals with a skeleton (notably, humans) do. A series of stills from one of their videos and a lovely diagram of the arm "joints" of an octopus who is about to eat an unhappy-looking fish are shown below:
It turns out that most of the distance covered in this movement sequence comes from the arms rotation about the medial joint (the yellow one), much as most of the effective range of human retrieval movements come from flexion of the elbow. After some more detailed analysis of the kinetics of this movement (which Ill skip here - but please check out the paper if youre interested) the authors go on to probe the pattern of muscle activity that is responsible for this movement as they did in their earlier studies (for a brief explanation of their methods, see my earlier post; for a longer one, see the paper reference therein.) They found differences in patterns of muscle activity depending upon where in the arm recordings were being made. When they looked proximally to the medial joint (eg. in arm segment L1 in the above diagram,) they found that a wave of muscle activity propagated away from the body, as it does in reaching movements. When they recorded from a portion of the arm distal to the medial joint (eg. in arm segment L2,) they found that muscle activity was propagating in the opposite direction - from the tip of the arm towards the base.
Using these results, the authors offer an elegant explanation of the neural control of this behavior. They suggest that the initiation of a retrieval movement involves the initiation of two waves of muscle activity, one starting from the tip of the arm and one from the base. Where these waves meet, the medial joint is formed. In this way, the octopus nervous system simplifies the problem of finding an efficient way to retrieve an object, a problem which would be hard to solve on the basis of proprioception or neural control contingent on a direct representation of sensory space due to the flexibility of the octopuss body.
In case you were wondering (I sure was), an experiment that was reported in the supplementary material (though it seems pretty important to me) revealed that retrieval could not be elicited in denervated arms in the way that arm extension can. Therefore, it appears that some input from the central nervous system is required to initiate this more complicated movement, although it is still possible (and seems likely) that, once initiated, the movement is driven primarily by peripheral mechanisms local to the arm performing the movement. The authors found that ablation of the anterior basal lobe left octopuses unable to initiate object retrieval, confirming its suspected function as a motor center in the octopus.
The authors finally put forth a hypothesis of convergent evolution of reaching movements between octopods and vertebrates:
It is especially surprising that of all possible
geometrical structures and motor control strategies
with which a flexible arm can bring an object to the
mouth, the octopus generates a quasi-articulated structure
with a striking morphological and kinematic resemblance
to the multijoint articulated limbs of vertebrates.
Because the hypothetical common ancestor of cephalopods
and vertebrates dates back to the beginning of
Cambrian era (about 540 million years ago), fetching
appears to be a genuine and rare case of evolutionary
functional convergence, where two independent attributes
(morphology and neural control) coevolved to
achieve a common goal.
I have no particular problem with this hypothesis. Id be interested to see if these types of movements are present in other species of cephalopods, both decapods and other octopod varieties. I think that the case for convergent evolution in this instance will always be a hard sell, because (unlike, for example, the eye) the anatomy of the body parts executing the movement in question are so different. In addition, the movements studied in this paper were elicited in very specific conditions using octopuses that were trained to extend their arms and wait for food to be pressed to them, leaving it unclear what other types of movements they might make in retrieving an object as well as the relative importance of the aforementioned quasi-articulated arm movements in the ethogram of the octopus. Those criticisms aside, Im willing to accept the idea that articulated movement really does represent a good solution to the problem of controlling movement, because it shows up across animalia so often and in so many forms. Why wouldnt we expect the octopus to get in on the action?
Thanks for reading!
Sumbre, G., Fiorito, G., Flash, T., & Hochner, B. (2006). Octopuses Use a Human-like Strategy to Control Precise Point-to-Point Arm Movements Current Biology, 16 (8), 767-772 DOI: 10.1016/j.cub.2006.02.069
Read more »
It has been shown that reaching movements by octopuses are controlled by the nervous system of the arms relatively autonomously from the central nervous system; that is, a severed arm can complete these movements on its own, given the proper stimulation of the base of the nerve cord of the arm. This is all well and good, as the movements being studied were rather simple, involving the extension of an arm. This reaching movement was found to consist of a propagating wave of muscle activity down the arm, a solution to the control of such a flexible appendage that greatly reduces the amount of neural computation that is needed to make such a movement.)
The study Ill look at today is Octopuses Use a Human-like Strategy to Control Precise Point-to-Point Arm Movements by Sumbre et al (2006). In it, the authors study a more complicated movement: retrieval of an object using a single arm. This is a problem of interest to neuroscientists and roboticists, because understanding how the octopus generates controlled, precise movement using an appendage with so many possible movements might give us some insight into the optimal solution of this problem. This could help reveal general rules of efficiency in neural programming.
Beginning (as is advisable) at the beginning, the authors videotaped reaching movements in O. vulgaris that were elicited by touching a piece of food to the animals outstretched arm. Their observations revealed that octopuses create joints in their arm during this movement, around which they move stiffened segments of the arm much the same way that animals with a skeleton (notably, humans) do. A series of stills from one of their videos and a lovely diagram of the arm "joints" of an octopus who is about to eat an unhappy-looking fish are shown below:
It turns out that most of the distance covered in this movement sequence comes from the arms rotation about the medial joint (the yellow one), much as most of the effective range of human retrieval movements come from flexion of the elbow. After some more detailed analysis of the kinetics of this movement (which Ill skip here - but please check out the paper if youre interested) the authors go on to probe the pattern of muscle activity that is responsible for this movement as they did in their earlier studies (for a brief explanation of their methods, see my earlier post; for a longer one, see the paper reference therein.) They found differences in patterns of muscle activity depending upon where in the arm recordings were being made. When they looked proximally to the medial joint (eg. in arm segment L1 in the above diagram,) they found that a wave of muscle activity propagated away from the body, as it does in reaching movements. When they recorded from a portion of the arm distal to the medial joint (eg. in arm segment L2,) they found that muscle activity was propagating in the opposite direction - from the tip of the arm towards the base.
Using these results, the authors offer an elegant explanation of the neural control of this behavior. They suggest that the initiation of a retrieval movement involves the initiation of two waves of muscle activity, one starting from the tip of the arm and one from the base. Where these waves meet, the medial joint is formed. In this way, the octopus nervous system simplifies the problem of finding an efficient way to retrieve an object, a problem which would be hard to solve on the basis of proprioception or neural control contingent on a direct representation of sensory space due to the flexibility of the octopuss body.
In case you were wondering (I sure was), an experiment that was reported in the supplementary material (though it seems pretty important to me) revealed that retrieval could not be elicited in denervated arms in the way that arm extension can. Therefore, it appears that some input from the central nervous system is required to initiate this more complicated movement, although it is still possible (and seems likely) that, once initiated, the movement is driven primarily by peripheral mechanisms local to the arm performing the movement. The authors found that ablation of the anterior basal lobe left octopuses unable to initiate object retrieval, confirming its suspected function as a motor center in the octopus.
The authors finally put forth a hypothesis of convergent evolution of reaching movements between octopods and vertebrates:
It is especially surprising that of all possible
geometrical structures and motor control strategies
with which a flexible arm can bring an object to the
mouth, the octopus generates a quasi-articulated structure
with a striking morphological and kinematic resemblance
to the multijoint articulated limbs of vertebrates.
Because the hypothetical common ancestor of cephalopods
and vertebrates dates back to the beginning of
Cambrian era (about 540 million years ago), fetching
appears to be a genuine and rare case of evolutionary
functional convergence, where two independent attributes
(morphology and neural control) coevolved to
achieve a common goal.
I have no particular problem with this hypothesis. Id be interested to see if these types of movements are present in other species of cephalopods, both decapods and other octopod varieties. I think that the case for convergent evolution in this instance will always be a hard sell, because (unlike, for example, the eye) the anatomy of the body parts executing the movement in question are so different. In addition, the movements studied in this paper were elicited in very specific conditions using octopuses that were trained to extend their arms and wait for food to be pressed to them, leaving it unclear what other types of movements they might make in retrieving an object as well as the relative importance of the aforementioned quasi-articulated arm movements in the ethogram of the octopus. Those criticisms aside, Im willing to accept the idea that articulated movement really does represent a good solution to the problem of controlling movement, because it shows up across animalia so often and in so many forms. Why wouldnt we expect the octopus to get in on the action?
Thanks for reading!
Sumbre, G., Fiorito, G., Flash, T., & Hochner, B. (2006). Octopuses Use a Human-like Strategy to Control Precise Point-to-Point Arm Movements Current Biology, 16 (8), 767-772 DOI: 10.1016/j.cub.2006.02.069
Tuesday, March 17, 2015
5 Books to Read to a Dog
This got me to thinking. Since dogs are the audience, what books would they enjoy hearing? I composed a list of 5 early reader books to read to a dog. I tried to pick ones that both reader and listener would like. When I wasnt sure, I consulted my pug, Pablo, and he made the call.
1 The number one book was a no-brainer. Three Stories You Can Read to Your Dog by Sara Swan Miller. What dog wouldnt rejoice to hear stories written to suit his taste and interests? Theres a story about a "burglar," another about a bone, and a third about a "wild" dog who enjoys chasing cars and squirrels. And if your canine companion still hasnt had his fill, check out Three More Stories You Can Read to Your Dog by the same author.
Now here, in no particular order, are the rest.
2 For kids just starting out Go, Dog, Go by P.D. Eastman will put them on the road to reading. Dogs of all kinds, big ones, little ones, green ones, red ones, and yellow ones, take off on the page as they zoom about in cars, on boats, and even on skis. Pablo gives this book an enthusiastic thumbs up!
3 Dogs dont just like to listen to stories. Sometimes they are in the mood for some meaty nonfiction. Why Do Dogs Bark? by Joan Holub answers the many questions that dogs may wonder about in those odd moments when they arent nosing about in the trash can or digging up the garden. Kids will enjoy learning about their canine friends as well.
4 I dont have many heros. But Balto, a sled dog that helped get vital medicine to children in Nome, Alaska, back in 1925, is one of them. I first learned about Balto when I was researching a book about the great dogsled race that eventually became the Iditarod. Children reading The Bravest Dog Ever: The True Story of Balto by Natalie Standiford will be inspired to learn how dogs helped save lives, and the dogs hearing the stirring tale can bask in their ancestors glory.
Tuesday, March 10, 2015
Ax Belonging to a Human Giant Discovered in West Virginia
Ax Belonging to a Human Giant Discovered in West Virginia
West Virginia Historical Magazine, Volume-2-1902
Giants Axe
Charleston, West Virginia., March 17, 1902
Dear Mr. Ladley,
Some years ago when Colonel Ben Smith mound was opened by Professor Norris, of the Smithsonian, he found the skeleton of a giant, which measured seven feet eight inches in length.
This occurred about fifteen years ago. Now comes the sequel. A few days ago Joe Fister was ploughing near the mound an unearthed a stone ax. The ax is of granite, beautifully made and well preserved. It weighs seven pounds eight ounces. The largest ever found here.
Dr. J. N. Mahan brought this ax, and has it in his possession. Could this have been the giants ax?
Cant you get some of your correspondents to give an article on Indian axes, & c.
Very Truly Yours,
Robert Douglas Roller
Monday, March 9, 2015
50 Interesting Facts About Andres Bonifacio a Philippine National Hero The Hero of The Masses
50 Interesting Facts About Andres Bonifacio, a Philippine National Hero - The Hero of The Masses
Andres Bonifacio one of the greatest Filipinos,a real man of honor, a true hero
...
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Andres Bonifacio one of the greatest Filipinos,a real man of honor, a true hero
...100 Ancient Skeletons Discovered in A West Virginia Stone Tomb
100 Ancient Skeletons Discovered in A West Virginia Stone Tomb
Bridges crossing the Ohio River at Steubenville, Ohio. On the right bank and the West Virginia side was the location of the stone wall and mass graves within the cave.
History of the Pan Handle, West Virginia 1879
An Ancient Sepulcher
In the summer of 1834, one Samual Cummings, an enterprising stone-mason of Stuebenville, Ohio one day crossed the river to prospect along the ledge of rocks that line the hills on the Virginia side for a suitable place to quarry stone. In looking about he discovered a massive rock, that in some previous age of the world, had fallen from the overhanging cliffs above. While making an examination, with a view of quarrying it, he discovered an ancient stone wall built against one side of it, but almost hid from view by the accumulated rubbish of ages. Curiosity led him to throw this wall down, when an opening appeared in the rock a few feet from him, that disclosed a large cavern or vault scooped out of the underside of the rock, which, upon closer inspection, he found to contain a large number of human skeletons, packed together in perfect regularity. Visitors estimated the number at 75 to 100.
At the time of this discovery the proprietor of the land - Colonel Nathaniel Wells - lived several miles distant, and did not hear of it for several days. In the meantime, in the absence of anyone with authority to protect the place, visitors thronged to it by the hundreds, each one carrying away prominent portions of the remains, till they were scattered, as it were, to the winds. Thus were the remains of the dead, of a pre-historic race, dragged from the long repose of ages and ruthlessly destroyed, to gratify the idle curiosity of the ignorant and thoughtless.
The vault is located on the Virginia of the Ohio River, nearly opposite South Street, Steubenville, about 100 rods below Mr. Wells ferry landing, and a few east of the Pittsburgh, Wheeling and Kentucky Railroad.
History of the Pan Handle, West Virginia 1879
An Ancient Sepulcher
In the summer of 1834, one Samual Cummings, an enterprising stone-mason of Stuebenville, Ohio one day crossed the river to prospect along the ledge of rocks that line the hills on the Virginia side for a suitable place to quarry stone. In looking about he discovered a massive rock, that in some previous age of the world, had fallen from the overhanging cliffs above. While making an examination, with a view of quarrying it, he discovered an ancient stone wall built against one side of it, but almost hid from view by the accumulated rubbish of ages. Curiosity led him to throw this wall down, when an opening appeared in the rock a few feet from him, that disclosed a large cavern or vault scooped out of the underside of the rock, which, upon closer inspection, he found to contain a large number of human skeletons, packed together in perfect regularity. Visitors estimated the number at 75 to 100.
At the time of this discovery the proprietor of the land - Colonel Nathaniel Wells - lived several miles distant, and did not hear of it for several days. In the meantime, in the absence of anyone with authority to protect the place, visitors thronged to it by the hundreds, each one carrying away prominent portions of the remains, till they were scattered, as it were, to the winds. Thus were the remains of the dead, of a pre-historic race, dragged from the long repose of ages and ruthlessly destroyed, to gratify the idle curiosity of the ignorant and thoughtless.
The vault is located on the Virginia of the Ohio River, nearly opposite South Street, Steubenville, about 100 rods below Mr. Wells ferry landing, and a few east of the Pittsburgh, Wheeling and Kentucky Railroad.
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