New determination of zonal harmonics coeffi- cients of the earth's gravitational potential special report no. 165

Zonal harmonics coefficient determination of earth gravitational potentia

Long term variation of the solar diurnal anisotropy of galactic cosmic rays observed with the Nagoya multi-directional muon detector

We analyze the three dimensional anisotropy of the galactic cosmic ray (GCR) intensities observed independently with a muon detector at Nagoya in Japan and neutron monitors over four solar activity cycles. We clearly see the phase of the free-space diurnal anisotropy shifting toward earlier hours around solar activity minima in A>0 epochs, due to the reduced anisotropy component parallel to the mean magnetic field. The average parallel component is consistent with a rigidity independent spectrum, while the perpendicular component increases with GCR rigidity. We suggest that this harder spectrum of the perpendicular component is due to contribution from the drift streaming. We find that the bidirectional latitudinal density gradient is positive in A>0 epoch, while it is negative in A<0 epoch, in accord with the drift model prediction. The radial density gradient, on the other hand, varies with ~11-year cycle with maxima (minima) in solar maximum (minimum) periods, but there is no significant difference seen between average radial gradients in A>0 and A<0 epochs. The average parallel mean free path is larger in A0. We also find, however, that parallel mean free path (radial gradient) appears to persistently increase (decreasing) in the last three cycles of weakening solar activity. We suggest that simple differences between these parameters in A>0 and A<0 epochs are seriously biased by these long-term trends.Comment: accepted for the publication in the Astrophysical Journa

Life Satisfaction of Undergraduate Students: Extrinsic and Intrinsic Motivators

In college, choosing a major involves thinking about its extrinsic and intrinsic attributes, for instance its pecuniary benefits versus the degree to which it is internally rewarding. Some students may choose lucrative majors over those which they believe are internally rewarding and vice versa. Previous research has shown that those who pursue intrinsic goals are happier relative to those who pursue extrinsic ones. However, people tend to overestimate the life satisfaction gained by extrinsic needs while underestimating the satisfaction gained by intrinsic needs. It is possible that students choosing a major for reasons conflicting with their personal goals may suffer from lowered life satisfaction. Nonetheless, the temporary circumstances of college students may create a unique dynamic from what has previously been studied. 270 University of Hawai’i at Mānoa college students were surveyed at random. Constructs such as optimism and feelings of community, among others, were found to be indicators of increased life satisfaction. This research may suggest that factors such as the possibility of employment and financial prospects, in addition to other known correlates are key determinants of life satisfaction in college students.Economic

Intrinsic Linking and Knotting of Graphs

An analog to intrinsic linking, intrinsic even linking, is explored in the first half of this paper. Four graphs are established to be minor minimal intrinsically even linked, and it is conjectured that they form a complete minor minimal set. Some characterizations are given, using the simplest of the four graphs as an integral part of the arguments, that may be useful in proving the conjecture. The second half of this paper investigates a new approach to intrinsic knotting. By adapting knot energy to graphs, it is hoped that intrinsic knotting can be detected through direct computation. However, graph energies are difficult to compute, and it is unclear whether they can be used to determine whether a graph is intrinsically knotted

DEFORMATIONS OF REDUCIBLE SL(n, C) REPRESENTATIONS OF FIBERED 3-MANIFOLD GROUPS

Let M_φ be a surface bundle over a circle with monodromy φ : S → S. We study deformations of certain reducible representations of π_1(M_φ) into SL(n, C), obtained by composing a reducible representation into SL(2, C) with the irreducible representation SL(2, C) → SL(n, C). In particular, we show that under certain conditions on the eigenvalues of φ∗, the red cible representation is contained in a (n + 1 + k)(n − 1) dimensional component of the representation variety, where k is the number of components of ∂M_φ. This result applies to mapping tori of pseudo-Anosov maps with orientable invariant foliations whenever 1 is not an eigenvalue of the induced map on homology, where the reducible representation is also a limit of irreducible representations

Heat dissipation in water-cooled reflectors

The energy balance of a lamp varies with the thermal and optical characteristics of the reflector. The photosynthetic radiation efficiency of lamps, defined as input power divided by photosynthetically active radiation (PAR, 400-700 nm) emitted from the lamp ranges between 0.17 and 0.26. The rest of the energy input is wasted as longwave (3000 nm and over) and non-PAR shortwave radiation (from 700 nm to 3000 nm), convective, and conductive heat from the lamp, reflector, and ballast, and simply for increasing the cooling load. Furthermore, some portion of the PAR is uselessly absorbed by the inner walls, shelves, vessels, etc. and some portion of the PAR received by the plantlets is converted into sensible and latent heat. More than 98% of the energy input is probably converted into heat, with only less than 2% of the energy input being converted into chemical energy as carbohydrates by photosynthesis. Therefore, it is essential to reduce the generation of heat in the culture room in order to reduce the cooling load. Through use of a water-cooled reflector, the generation of convective and conductive heat and longwave radiation from the reflector can be reduced, without reduction of PAR

Seasonal variations of the geopotential inferred from satellite observations

Annual variation of geopotential determined by tracking satellite