9,714 research outputs found
On the CCD Calibration of Zwicky galaxy magnitudes & The Properties of Nearby Field Galaxies
We present CCD photometry for galaxies around 204 bright (m_Z < 15.5) Zwicky
galaxies in the equatorial extension of the APM Galaxy Survey, sampling and
area over 400 square degrees, which extends 6 hours in right ascension. We fit
a best linear relation between the Zwicky magnitude system, m_Z, and the CCD
photometry, B, by doing a likehood analysis that corrects for Malmquist bias.
This fit yields a mean scale error in Zwicky of 0.38 mag per magnitude: ie
Delta m_Z = (0.62 \pm 0.05) Delta B and a mean zero point of = -0.35
\pm 0.15 mag. The scatter around this fit is about 0.4 mag. Correcting the
Zwicky magnitude system with the best fit model results in a 60% lower
normalization and 0.35 mag brighter M_* in the luminosity function. This brings
the CfA2 luminosity function closer to the other low redshift estimations (eg
Stromlo-APM or LCRS). We find a significant positive angular correlation of
magnitudes and position in the sky at scales smaller than about 5 armin, which
corresponds to a mean separation of 120 Kpc/h. We also present colours, sizes
and ellipticities for galaxies in our fields which provides a good local
reference for the studies of galaxy evolution.Comment: Full size figures can be found in
http://www.ieec.fcr.es/cosmo-www/zwicky.ps Version accepted for publication
in MNRAS. Extended discussion on properties of nearby galaxies. References
added. An inconsistency in the R band isophote used has been corrected. Main
results and conclusions are unchange
Farming on the Edge in Poland. Options for Improving Farm Incomes for the Main Types of Farms after Joining the EU
The aim of the paper is to examine the financial impacts of introducing the Common Agricultural Policy into the Polish farming sector after the accession to the EU. Aggregated results from farm level modelling using linear programming for 210 farm types representing the variety of Polish farms, and 90% of the agricultural sector are presented. The benefits of the negotiated subsidy arrangements are unequally distributed and only a partial solution to low farm family incomes.EU accession, Polish Agriculture, direct payments, typical farms, farm model., Farm Management,
Optimal Clustering under Uncertainty
Classical clustering algorithms typically either lack an underlying
probability framework to make them predictive or focus on parameter estimation
rather than defining and minimizing a notion of error. Recent work addresses
these issues by developing a probabilistic framework based on the theory of
random labeled point processes and characterizing a Bayes clusterer that
minimizes the number of misclustered points. The Bayes clusterer is analogous
to the Bayes classifier. Whereas determining a Bayes classifier requires full
knowledge of the feature-label distribution, deriving a Bayes clusterer
requires full knowledge of the point process. When uncertain of the point
process, one would like to find a robust clusterer that is optimal over the
uncertainty, just as one may find optimal robust classifiers with uncertain
feature-label distributions. Herein, we derive an optimal robust clusterer by
first finding an effective random point process that incorporates all
randomness within its own probabilistic structure and from which a Bayes
clusterer can be derived that provides an optimal robust clusterer relative to
the uncertainty. This is analogous to the use of effective class-conditional
distributions in robust classification. After evaluating the performance of
robust clusterers in synthetic mixtures of Gaussians models, we apply the
framework to granular imaging, where we make use of the asymptotic
granulometric moment theory for granular images to relate robust clustering
theory to the application.Comment: 19 pages, 5 eps figures, 1 tabl
Field Quantization, Photons and Non-Hermitean Modes
Field quantization in three dimensional unstable optical systems is treated
by expanding the vector potential in terms of non-Hermitean (Fox-Li) modes in
both the cavity and external regions. The cavity non-Hermitean modes (NHM) are
treated using the paraxial and monochromaticity approximations. The NHM
bi-orthogonality relationships are used in a standard canonical quantization
procedure based on introducing generalised coordinates and momenta for the
electromagnetic (EM) field. The quantum EM field is equivalent to a set of
quantum harmonic oscillators (QHO), associated with either the cavity or the
external region NHM. This confirms the validity of the photon model in unstable
optical systems, though the annihilation and creation operators for each QHO
are not Hermitean adjoints. The quantum Hamiltonian for the EM field is the sum
of non-commuting cavity and external region contributions, each of which is sum
of independent QHO Hamiltonians for each NHM, but the external field
Hamiltonian also includes a coupling term responsible for external NHM photon
exchange processes. Cavity energy gain and loss processes is associated with
the non-commutativity of cavity and external region operators, given in terms
of surface integrals involving cavity and external region NHM functions on the
cavity-external region boundary. The spontaneous decay of a two-level atom
inside an unstable cavity is treated using the essential states approach and
the rotating wave approximation. Atomic transitions leading to cavity NHM
photon absorption have a different coupling constant to those leading to photon
emission, a feature resulting from the use of NHM functions. Under certain
conditions the decay rate is enhanced by the Petermann factor.Comment: 38 pages, tex, 2 figures, ps. General expression for decay rate
added. To be published in Journal of Modern Optic
STABILIZATION OF UPLAND RICE PRODUCTION UNDER SHORTENED FALLOW IN WEST AFRICA: RESEARCH PRIORITY SETTING IN A DYNAMIC ENVIRONMENTAL AND ECONOMIC CLIMATE
This paper presents a dynamic model of land resource degradation and shifting rice cultivation in West Africa based upon Boserup and Dvorak. The model indicates the ex ante impact of research strategies to maximize the economic benefits of host plant resistance and land resource management and thereby stabilize yield decline and reduce land degradation.Land Economics/Use, Resource /Energy Economics and Policy,
Overlook of Sino-American Power Transition: With Special Considerations of Cyber Warfare
Examination of the current posssible power transition between the Unoted States and China and how it relates to Power Transition Theory. then an overlook into how cyber warfare will play a part in a huge power transition, a topic that is not included in the antiquated PTT
The Effect Of Intermittent Cooling On Simulated Basketball Game Performance
Context: Hyperthermia is induced during prolonged exercise which promotes fatigue and a decline in performance. Basketball athletes have trouble preventing an onset of hyperthermia; thus, cryotherapy is applied intermittently to combat the negative effects.
Objective: To determine, (1) effect intermittent cooling has on simulated basketball performance, perceived exertion and perceived recovery; and (2) change in performance while applying two different forms of intermittent cooling during the Basketball Specific Fatigue Protocol (BSFP).
Design: Crossover study design.
Setting: Indoor collegiate basketball court.
Patients or Other Participants: Sixteen competitively trained recreational basketball athletes (15 males, 1 female; age = 21.1 ± 1.2 yr).
Main Outcome Measures: Participants completed 3 trials of the BSFP. Between quarters, intermittent cooling was applied for 5-minutes to the lower extremity using either a phase changing material (PCM), wetted ice (WI) or received no treatment (control). Change in countermovement jump height (ΔCMJ), 10m sprint time (ΔST), heart rate (ΔHR), ratings of perceived exertion (RPE) and perceived recovery score (PRS) were recorded each quarter.
Results: PRS found to significantly increase starting quarter 2 (Q2), (7.0 ± 2.0, p = 0.02), with significantly higher PRS at Q2 using the PCM (7.5 ± 2.0, p \u3c 0.01). HR and ST saw significant change between quarters (ΔHR: Q1 = 81.8 ± 2.6 bpm, p \u3c 0.01; ΔST: Q1 to Q4 (- 0.2 ± 0.1 s, p = 0.02), Q2 to Q4 (- 0.1 ± 0.0 s, p = 0.03), but not between conditions (ΔHR: p = 0.51, ΔST: p = 0.33). RPE significantly increased each quarter until the completion of the simulated game (p
Conclusions: Intermittent cooling, applied to the lower extremity via PCM, can increase perceived recovery through the first half of simulated basketball game performance
From Presumed Fathers to Lesbian Mothers: Sex Discrimination and the Legal Construction of Parenthood
In Part I of this article, Dalton briefly reviews the way legal scholars commonly define sex-based discrimination, particularly as it pertains to issues of reproduction. Part II is a brief historical review of legal constructions of parenthood. In Part III, Dalton examines two legal concepts: retroactive legitimation and presumed fatherhood. Both concepts were introduced in 1872 and each independently encouraged judges to think of fatherhood as consisting of two distinct spheres, the biological and the social. She then traces the legal development of these concepts through a series of presumed father, retroactive legitimation, and putative father cases. In Part IV Dalton extends the analysis to include legal constructions of motherhood by introducing lesbian co-mother and female surrogacy cases into the mix. This allows the author to directly compare legal constructions of motherhood to legal constructions of fatherhood. In Part V Dalton discusses gendered aspects of the legal institution of marriage and the complicated role marriage plays in legal constructions of parenthood. In Part VI she delves into several recent lesbian co-mother and surrogacy cases to explore how some judges are attempting to expand legal constructions of motherhood in ways that would bring them more on par with legal constructions of fatherhood. And finally, in Part VII, Dalton offers final remarks and concludes that judges\u27 inability to conceive of a gender neutral subject, at least when considering issues related to human reproduction, creates serious legal disadvantages for virtually all women. As the analysis below makes clear, the resulting discrimination is grounded in gendered constructions of parenthood and not, as many courts conclude, in the biological differences between men and women
Characteristics and problems of successful extension-related community clubs in Knox County, Tennessee, 1944-1977
Successful Knox County Community Clubs, organized prior to 1955 and active at the time of the study, were studied to compare and characterize the clubs and to Identify factors contributing to their success. Information was derived primarily from interviews with key members from selected clubs, also from interviews with other key people associated with selected clubs during periods studied, from review of records, club reports, minutes, scrapbooks, library materials, etc.
Most clubs started because of special needs or interests of residents and because of the influence of Extension and other professionals. The East Tennessee Community Improvement Program influenced selected clubs\u27 start, and also their continuation through the time of the study. During the study period, 1944-1977, communities grew in population and farming declined.
The major problems faced by clubs during the Formative Period, 1944-1954, were related to school, library and the need for community services; during Intermediate Years, 1955-1969, the problems mostly had to do with education, beautification, need for a community center, community services and parks and recreation; and in Recent Years, 1970-1977, basic club organization, land use planning and law enforcement were major problems. It was found that the clubs studied were successful in completing projects relating to specific community problems. They were receptive to help from Extension and other outside resources, and cooperated well with county government and other public and private organizations.
Implications were drawn and recommendations made for use of the findings and for further study
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