616 research outputs found
Misuse of the Less Restrictive Alternative Inquiry in Rule of Reason Analysis
The rule of reason articulated by the Supreme Court in 1918 in Chicago Board of Trade has long been the target of scorn and ridicule by scholars and judges. The rule, which is used to determine the legality of restraints under Section 1 of the Sherman Act, instructs courts to identify and balance a restraint\u27s competitive effects - restraints that are net procompetitive are legal. Critics argue that the rule is easy to state but impossible to apply, as it asks courts to identify the unidentifiable and balance the unbalanceable. Despite the steady criticism, the rule has remained the exclusive rule of reason approach of the Supreme Court for nearly a century.
Yet, perhaps in an attempt to improve the test, each of the federal circuits has incorporated the less restrictive alternative inquiry as an independent and dispositive prong of the rule of reason. Under this newly created test, a restraint that achieves a net procompetitive benefit - and thus is legal under the Supreme Court standard - is illegal if the procompetitive benefits could have been attained by a less restrictive alternative. Surprisingly, the new test has not only avoided much criticism, but has received widespread support from scholars across the ideological spectrum.
Rather than improve the rule of reason, however, use of the less restrictive alternative inquiry as a dispositive factor transforms an already difficult analysis into a virtually unworkable multi-tiered balancing adventure. It adds a new level of confusion and opacity to Section 1 analysis and threatens to change the role of antitrust law from an ex ante deterrent of net anticompetitive behavior to an ex post regulator of net procompetitive business decisions.
This Article examines the historical use of the less restrictive alternative inquiry and its emergence in the modern rule of reason analysis. The Article argues that use of the inquiry in the modern rule of reason is both theoretically and practically flawed. The Article concludes that proof of less restrictive alternatives should be used solely as proof of anticompetitive intent, which in turn should only be used as one factor to aid courts in balancing the competitive effects of a restraint of trade. Such use of the search for less restrictive alternatives is consistent with nearly one hundred years of Supreme Court precedent and maintains the proper focus of the antitrust laws on the competitive impact of the restraint
EFECTIVIDAD Y ACTIVIDAD. MEDICIONES PARA EVALUAR DOCENTES
La evaluación de docentes se puede realizar desde diferentes puntos de vista, desde diferentes observadores y con distinto propósito. Este artículo intenta plantear algunos de los objetivos que normalmente se usan y las formas actuales de entender y medir aproximaciones a esos objetivos. Efectividad se refiere a lograr los objetivos, en este caso cuántos alumnos aprenden lo suficiente para aprobar una asignatura. Actividad se refiere a cuán intenso es el esfuerzo docente para ese logro. Ambas son medidas que ayudan a administrar y gestionar el proceso educativo. Todas estas mediciones están teñidas por las formas y métodos pedagógicos utilizados en cada situación. Hay características que se pueden medir para toda una cátedra en forma separada de las de docentes individuales. Tampoco son idénticas las mediciones para docentes que dictan clases con asistencia obligatoria o sin ella. En este artículo se tratan indicadores que cada cátedra puede medir respecto de las tareas docentes en sus diferentes aspectos y se elaboran algunos índices que resultaron útiles en la aplicación práctica en la Facultad de Ciencias Económicas de la Universidad Nacional de Tucumán
RESIK observations of He-like Ar X-ray line emission in solar flares
The Ar XVII X-ray line group principally due to transitions 1s2 - 1s2l (l=s,
p) near 4 Anstroms was observed in numerous flares by the RESIK bent crystal
spectrometer aboard CORONAS-F between 2001 and 2003. The three line features
include the Ar XVII w (resonance line), a blend of x and y (intercombination
lines), and z (forbidden line), all of which are blended with Ar XVI
dielectronic satellites. The ratio G, equal to [I(x+y) + I(z)]/I(w), varies
with electron temperature Te mostly because of unresolved dielectronic
satellites. With temperatures estimated from GOES X-ray emission, the observed
G ratios agree fairly well with those calculated from CHIANTI and other data.
With a two-component emission measure, better agreement is achieved. Some S XV
and S XVI lines blend with the Ar lines, the effect of which occurs at
temperatures greater than 8MK, allowing the S/Ar abundance ratio to be
determined. This is found to agree with coronal values. A nonthermal
contribution is indicated for some spectra in the repeating-pulse flare of 2003
February 6.Comment: Latex file and 3 ps files. Astrophysical Journal Letters (accepted,
June 2008
Solar off-limb line widths: Alfven waves, ion-cyclotron waves, and preferential heating
Alfven waves and ion-cyclotron absorption of high-frequency waves are
frequently brought into models devoted to coronal heating and fast solar-wind
acceleration. Signatures of ion-cyclotron resonance have already been observed
in situ in the solar wind (HELIOS spacecrafts) and, recently, in the upper
corona (UVCS/SOHO remote-sensing results). We propose a method to constrain
both the Alfven wave amplitude and the preferential heating induced by
ion-cyclotron resonance, above a partially developed polar coronal hole
observed with the SUMER/SOHO spectrometer. The instrumental stray light
contribution is first substracted from the spectra. By supposing that the
non-thermal velocity is related to the Alfven wave amplitude, it is constrained
through a density diagnostic and the gradient of the width of the Mg X 625 A
line. The temperatures of several coronal ions, as functions of the distance
above the limb, are then determined by substracting the non-thermal component
to the observed line widths. The effect of stray light explains the apparent
decrease with height in the width of several spectral lines, this decrease
usually starting about 0.1-0.2 Rs above the limb. This result rules out any
direct evidence of damping of the Alfven waves, often suggested by other
authors. We also find that the ions with the smallest charge-to-mass ratios are
the hottest ones at a fixed altitude and that they are subject to a stronger
heating, as compared to the others, between 57" and 102" above the limb. This
constitutes a serious clue to ion-cyclotron preferential heating.Comment: 15 pages, 12 figures, 3 table
Coronal ion-cyclotron beam instabilities within the multi-fluid description
Spectroscopic observations and theoretical models suggest resonant
wave-particle interactions, involving high-frequency ion-cyclotron waves, as
the principal mechanism for heating and accelerating ions in the open coronal
holes. However, the mechanism responsible for the generation of the
ion-cyclotron waves remains unclear. One possible scenario is that ion beams
originating from small-scale reconnection events can drive micro-instabilities
that constitute a possible source for the excitation of ion-cyclotron waves. In
order to study ion beam-driven electromagnetic instabilities, the multi-fluid
model in the low-beta coronal plasma is used. While neglecting the electron
inertia this model allows one to take into account ion-cyclotron wave effects
that are absent from the one-fluid MHD model. Realistic models of density and
temperature as well as a 2-D analytical magnetic field model are used to define
the background plasma in the open-field funnel region of a polar coronal hole.
Considering the WKB approximation, a Fourier plane-wave linear mode analysis is
employed in order to derive the dispersion relation. Ray-tracing theory is used
to compute the ray path of the unstable wave as well as the evolution of the
growth rate of the wave while propagating in the coronal funnel. We demonstrate
that, in typical coronal holes conditions and assuming realistic values of the
beam velocity, the free energy provided by the ion beam propagating parallel
the ambient field can drive micro-instabilities through resonant ion-cyclotron
excitation.Comment: 8 pages, 6 figures, submitted to A&
Search for photospheric footpoints of quiet Sun transition region loops
CONTEXT:The footpoints of quiet Sun Transition Region (TR) loops do not seem
to coincide with the photospheric magnetic structures appearing in traditional
low-sensitivity magnetograms.
AIMS: To look for the so-far unidentified photospheric footpoints of TR loops
using G-band bright points (BPs) as proxies for photospheric magnetic field
concentrations.
METHODS: Comparison of TR measurements with SoHO/SUMER and photospheric
magnetic field observations obtained with the Dutch Open Telescope.
RESULTS: Photospheric BPs are associated with bright TR structures, but they
seem to avoid the brightest parts of the structure. BPs appear in regions that
are globally redshifted, but they avoid extreme velocities. TR explosive events
are not clearly associated with BPs.
CONCLUSIONS: The observations are not inconsistent with the BPs being
footpoints of TR loops, although we have not succeeded to uniquely identify
particular BPs with specific TR loops.Comment: Accepted for publication in A&A. 10 pages, 10 figures. Due to size
limitations, the quality of fig3 is not goo
Highly Ionized Potassium Lines in Solar X-ray Spectra and the Abundance of Potassium
The abundance of potassium is derived from X-ray lines observed during flares
by the RESIK instrument on the solar mission CORONAS-F between 3.53 A and 3.57
A. The lines include those emitted by He-like K and Li-like K dielectronic
satellites, which have been synthesized using the CHIANTI atomic code and newly
calculated atomic data. There is good agreement of observed and synthesized
spectra, and the theoretical behavior of the spectra with varying temperature
estimated from the ratio of the two GOES channels is correctly predicted. The
observed fluxes of the He-like K resonance line per unit emission measure gives
log A(K) = 5.86 (on a scale log A(H) = 12), with a total range of a factor 2.9.
This is higher than photospheric abundance estimates by a factor 5.5, a
slightly greater enhancement than for other elements with first ionization
potential (FIP) less than about 10 eV. There is, then, the possibility that
enrichment of low-FIP elements in coronal plasmas depends weakly on the value
of the FIP which for K is extremely low (4.34 eV). Our work also suggests that
fractionation of elements to form the FIP effect occurs in the low chromosphere
rather than higher up, as in some models.Comment: 14 pages, 3 figure
First Light Measurements with the XMM-Newton Reflection Grating Spectrometers: Evidence for an Inverse First Ionisation Potential Effect and Anomalous Ne A bundance in the Coronae of HR 1099
The RS CVn binary system HR 1099 was extensively observed by the XMM-Newton
observatory in February 2000 as its first-light target. A total of 570 ks of
exposure time was accumulated with the Reflection Grating Spectrometers (RGS).
The integrated X-ray spectrum between 5-35 Angstrom is of unprecedented quality
and shows numerous features attributed to transitions of the elements C, N, O,
Ne, Mg, Si, S, Fe, and Ni. We perform an in-depth study of the elemental
composition of the average corona of this system, and find that the elemental
abundances strongly depend on the first ionisation potential (FIP) of the
elements. But different from the solar coronal case, we find an inverse FIP
effect, i.e., the abundances (relative to oxygen) increase with increasing FIP.
Possible scenarios, e.g., selective enrichment due to Ne-rich flare-like
events, are discussed.Comment: 5 pages, 4 figures. Accepted by A&A Letters, XMM issu
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