3,875 research outputs found
Charter and Party Boat Operators in the U.S. Gulf of Mexico: A Social Structure Perspective
To better address the charter and party boat fishery needs in the U.S. Gulf of Mexico, fishery managers must understand the linkages between the industry and other groups and organizations that affect its success. Gulf state charter and party boat operators were interviewed to ascertain the extent of their social network linkages, membership in community organizations, business community relationships, and linkages to information sources. Approximately one-third to one-half of the charter and party boat operators did not belong to local community organizations that could assist their business through tourism promotion or natural resource protection. Despite their limited integration in the community, the vast majority of operators gave and received referrals from other businesses. Of four major information sources, the National Weather Service and the County Marine Extension agents were rated highest and lowest, respectively, in mean importance to charter and party boat operators. Results suggest that business success can be enhanced by strengthening network ties between operators and local businesses, chambers of commerce, and tourism organizations. For this to occur, individual operators and charter/party boat organizations need to become more effective in representing industry interests. Informational linkages between industry and govemment agencies also need improvement
Reconstructing the Accretion History of the Galactic Stellar Halo from Chemical Abundance Ratio Distributions
Observational studies of halo stars during the last two decades have placed
some limits on the quantity and nature of accreted dwarf galaxy contributions
to the Milky Way stellar halo by typically utilizing stellar phase-space
information to identify the most recent halo accretion events. In this study we
tested the prospects of using 2-D chemical abundance ratio distributions
(CARDs) found in stars of the stellar halo to determine its formation history.
First, we used simulated data from eleven "MW-like" halos to generate satellite
template sets of 2-D CARDs of accreted dwarf satellites which are comprised of
accreted dwarfs from various mass regimes and epochs of accretion. Next, we
randomly drew samples of mock observations of stellar chemical
abundance ratios ([/Fe], [Fe/H]) from those eleven halos to generate
samples of the underlying densities for our CARDs to be compared to our
templates in our analysis. Finally, we used the expectation-maximization
algorithm to derive accretion histories in relation to the satellite template
set (STS) used and the sample size. For certain STS used we typically can
identify the relative mass contributions of all accreted satellites to within a
factor of 2. We also find that this method is particularly sensitive to older
accretion events involving low-luminous dwarfs e.g. ultra-faint dwarfs -
precisely those events that are too ancient to be seen by phase-space studies
of stars and too faint to be seen by high-z studies of the early Universe.
Since our results only exploit two chemical dimensions and near-future surveys
promise to provide dimensions, we conclude that these new
high-resolution spectroscopic surveys of the stellar halo will allow us to
recover its accretion history - and the luminosity function of infalling dwarf
galaxies - across cosmic time.Comment: Article contains 18 pages total (16 pages of main text + 2 pages of
Appendix) with 12 figures; accepted for publication in Ap
Residual Symmetries for Neutrino Mixing with a Large theta_13 and Nearly Maximal delta_D
The residual Z^s_2(k) and bar Z^s_2(k) symmetries induce a direct and unique
phenomenological relation with theta_x (= theta_13) expressed in terms of the
other two mixing angles, theta_s (= theta_12) and theta_a (= theta_23), and the
Dirac CP phase delta_D. Z^s_2(k) predicts a theta_x probability distribution
centered around 3^o ~ 6^o with an uncertainty of 2^o to 4^o while those from
bar Z^s_2(k) are approximately a factor of two larger. Either result fits the
T2K, MINOS and Double CHOOZ measurements. Alternately a prediction for the
Dirac CP phase delta_D results in a peak at +-74^o (+-106^o) for Z^s_2(k) or
+-123^o (+-57^o) for bar Z^s_2(k) which is consistent with the latest global
fit. We also give a distribution for the leptonic Jarslkog invariant J_v which
can provide further tests from measurements at T2K and NOvA.Comment: Accepted for publication in PR
Reaction of Lignite and Oxygen at Low Temperature: Heat of Reaction and Rate of Oxygen Consumption
the rate heat of oxidation for Ugalte la 90* C were studied as function© of tesaoeratura* content and prior ceddatioa. The oqpariMRltai procedures Involved passing oxygon throu^x a prepared eanple la an adiabatic calorimeter and aaaaurlag the t®aperatare riee and oxygen eoasuaed foe* a given time*
¥h« heat of oxidation asrooared to increase vith incroaninr, tersnerature. At 20* C, value© vera sporadic and ramiod down to 23.550 ^j|2^83n2 compared to values of 35,000 + 9,6GG and 89,000 ♦ 9,600 at 60* and 90* respectively. The low values at 20* C are attributed to the oocurraae© of increased nhysioal adsorption ZyQA\u27bS.V’B to Ctl£S%Lco3. X^JftCtiOKk •
At 20* C the smallest particle aia* of 0.125 to 0,036 inches gave low values for the heat of reaction (23,500 and 2^,800 calories per &rm aole osygan), while larger site© produced values greater than 70,8*»Q, The lor values are attributed to greater physical adsorption in the «*+i\u27*\u3c**• sines corresponding to Increased KOTC®SF« ^ti2l6 • -\u27V ■*» Jtjt
«*+i\u27*\u3c**• sines corresponding to Increased KOTC®SF« ^ti2l6 • -\u27V ■*» Jtjt !«■J~h .-» ,-. r-. J| M a- A\u27 n j, j~\u3e -vioul \u3e JTL ft -
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