3,568 research outputs found
Alien Registration- Newcomb, Elmer E. (Saint Albans, Somerset County)
https://digitalmaine.com/alien_docs/9737/thumbnail.jp
Scanning Electron Microscopy Laboratory Portfolio
These images were prepared by Ian Newcomb as part of the class MCR 484 Scanning Electron Microscopy at SUNY College of Environmental Science and Forestry, Fall 2016.
All images were acquired on the JEOL JSM 5800 LV Scanning Electron Microscope in the N. C. Brown Center for Ultrastructure Studie
Circadian Rhythms of Crawling and Swimming in the Nudibranch Mollusc Melibe leonina
Daily rhythms of activity driven by circadian clocks are expressed by many organisms, including molluscs. We initiated this study, with the nudibranch Melibe leonina, with four goals in mind: (1) determine which behaviors are expressed with a daily rhythm; (2) investigate which of these rhythmic behaviors are controlled by a circadian clock; (3) determine if a circadian clock is associated with the eyes or optic ganglia of Melibe, as it is in several other gastropods; and (4) test the hypothesis that Melibe can use extraocular photoreceptors to synchronize its daily rhythms to natural light-dark cycles. To address these goals, we analyzed the behavior of 55 animals exposed to either artificial or natural light-dark cycles, followed by constant darkness. We also repeated this experiment using 10 animals that had their eyes removed. Individuals did not express daily rhythms of feeding, but they swam and crawled more at night. This pattern of locomotion persisted in constant darkness, indicating the presence of a circadian clock. Eyeless animals also expressed a daily rhythm of locomotion, with more locomotion at night. The fact that eyeless animals synchronized their locomotion to the light-dark cycle suggests that they can detect light using extraocular photoreceptors. However, in constant darkness, these rhythms deteriorated, suggesting that the clock neurons that influence locomotion may be located in, or near, the eyes. Thus, locomotion in Melibe appears to be influenced by both ocular and extraocular photoreceptors, although the former appear to have a greater influence on the expression of circadian rhythms
The Heider balance - a continuous approach
The Heider balance (HB) is investigated in a fully connected graph of
nodes. The links are described by a real symmetric array r(i,j), i,j=1,...,N.
In a social group, nodes represent group members and links represent relations
between them, positive (friendly) or negative (hostile). At the balanced state,
r(i,j)r(j,k)r(k,i)>0 for all the triads (i,j,k). As follows from the structure
theorem of Cartwright and Harary, at this state the group is divided into two
subgroups, with friendly internal relations and hostile relations between the
subgroups. Here the system dynamics is proposed to be determined by a set of
differential equations. The form of equations guarantees that once HB is
reached, it persists. Also, for N=3 the dynamics reproduces properly the
tendency of the system to the balanced state. The equations are solved
numerically. Initially, r(i,j) are random numbers distributed around zero with
a symmetric uniform distribution of unit width. Calculations up to N=500 show
that HB is always reached. Time to get the balanced state varies with the
system size N as N^{-1/2}. The spectrum of relations, initially narrow, gets
very wide near HB. This means that the relations are strongly polarized. In our
calculations, the relations are limited to a given range around zero. With this
limitation, our results can be helpful in an interpretation of somestatistical
data.Comment: 9 pages, 4 figures. Int. J. Mod. Phys. C (2005), in prin
Flux and field line conservation in 3--D nonideal MHD flows: Remarks about criteria for 3--D reconnection without magnetic neutral points
We make some remarks on reconnection in plasmas and want to present some
calculations related to the problem of finding velocity fields which conserve
magnetic flux or at least magnetic field lines. Hereby we start from views and
definitions of ideal and non-ideal flows on one hand, and of reconnective and
non-reconnective plasma dynamics on the other hand. Our considerations give
additional insights into the discussion on violations of the frozen--in field
concept which started recently with the papers by Baranov & Fahr (2003a;
2003b). We find a correlation between the nonidealness which is given by a
generalized form of the Ohm's law and a general transporting velocity, which is
field line conserving.Comment: 9 pages, 2 figures, submitted to Solar Physic
First Results from Viper: Detection of Small-Scale Anisotropy at 40 GHZ
Results of a search for small-scale anisotropy in the cosmic microwave
background (CMB) are presented. Observations were made at the South Pole using
the Viper telescope, with a .26 degree (FWHM) beam and a passband centered at
40 GHz. Anisotropy band-power measurements in bands centered at l = 108, 173,
237, 263, 422 and 589 are reported. Statistically significant anisotropy is
detected in all bands.Comment: 5 pages, 4 figures, uses emulateapj.sty, submitted to ApJ Letter
The automation of a stellar proper motion measuring system Annual report, 1 Jul. 1966 - 30 Jun. 1967
Design and operation of automated stellar proper motion measuring syste
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