Isochronal synchronization of delay-coupled systems

We consider small network models for mutually delay-coupled systems which typically do not exhibit stable isochronally synchronized solutions. We show that for certain coupling architectures which involve delayed self feedback to the nodes, the oscillators become isochronally synchronized. Applications are shown for both incoherent pump coupled lasers and spatio-temporal coupled fiber ring lasers.Comment: 5 pages, accepted for publication in Physical Review

Microscale application of column theory for high resolution force and displacement sensing

We present the design, fabrication and experimental validation of a novel device that exploits the amplification of displacement and attenuation of structural stiffness in the post-buckling deformation of slender columns to obtain pico-Newton force and nanometer displacement resolution even under an optical microscope. The extremely small size, purely mechanical sensing scheme and vacuum compatibility of the instrument makes it compatible with existing visualization tools of nanotechnology. The instrument has a wide variety of potential applications ranging from electro-mechanical characterization of one dimensional solids to single biological cells

Dissociating Allopregnanolone Mnemonic Effects from Sedation

Allopregnanolone (Allop) is a neurosteroid metabolite of progesterone. Allop modulates cognition, specifically learning and memory, but these effects are frequently confounded by its anxiolytic and sedative properties. We attempted to dissociate the anxiolytic effects of Allop from its mnemonic effects by employing a pharmacological challenge with d- amphetamine. Because previous research suggests that the effects of Allop may vary with the cognitive domain being tested, we assessed both spatial and non-spatial memory. Spatial memory was tested in a Morris Water Maze, and non-spatial object memory was tested on a novel discrimination task. Allop, alone or in combination with d-amphetamine did not have any significant effects on spatial memory. Neither Allop nor amphetamine alone affected memory of a novel object relative to controls, but the combination of the two produced a dissociation and enhanced performance. The results suggest that, depending on the type of memory being tested, the sedative effects of Allop can be dissociated from mnemonic effects by co-administering a sub-threshold dose of d-amphetamine

To the Seniors

It scarcely seems a year ago that I was asked to prepare a short statement for inclusion in the 1959 Ames Forester. Time passes so rapidly! Now the editor of the 1960 publication has made a similar request

Preparation of Southern Pine for Preservation

Perhaps the most important portion of work connected with the preservative treatment of Southern Pine wood is the proper preparation of it for the reception of the preservative. The so-called empty cell processes of treatment with creosote oil are based on the fact that the material is thoroughly seasoned. Although a great quantity of unseasoned wood is prepared for treatment by a period of heating with live steam most of the authorities connected with the wood preserving industry are agreed that seasoned wood will receive a better and more uniform treatment than wood prepared by the steaming process. Most of the drying, curing, or seasoning is the result of slacking the material in the weather and giving what is commonly called air seasoning. Such being the case, the chief concern of the wood preserver is to secure the proper seasoning in the open, of the wood before it is sent to the wood preserving plant for the treatment with the designated preservative

Are We Too Many?

The greatly increased enrollment of students in the forest schools of the United States is viewed with considerable alarm by many, and the question is often heard, where will all of these students find employment? Perhaps it might be well to explore a few of the possibilities for men who have forestry training, particularly those possibilities in the field of the forest industries

The Calcasieu Pine District of Louisiana

Of all the tottering thrones of to-day none is more shaky than that of King “Pinus palustris”, who is ruling in the last decade of greatness of one of the world’s grandest kingdoms. The history of that kingdom is the story of the climax and decline of the great forests of southern long leaf yellow pine. It has not been many years since those magnificent southern forests stood silent and intact. Now it will not be long before the noise and bustle of the last big logging operation will die away, leaving behind destruction and desolation, except for a few scattered tracts of virgin timber and scant reproduction