149 research outputs found
Quantum statistics of overlapping modes in open resonators
We study the quantum dynamics of optical fields in weakly confining
resonators with overlapping modes. Employing a recently developed quantization
scheme involving a discrete set of resonator modes and continua of external
modes we derive Langevin equations and a master equation for the resonator
modes. Langevin dynamics and the master equation are proved to be equivalent in
the Markovian limit. Our open-resonator dynamics may be used as a starting
point for a quantum theory of random lasers.Comment: 6 pages, corrected typo
Photoassociation spectroscopy of cold calcium atoms
Photoassociation spectroscopy experiments on 40Ca atoms close to the
dissociation limit 4s4s 1S0 - 4s4p 1P1 are presented. The vibronic spectrum was
measured for detunings of the photoassociation laser ranging from 0.6 GHz to 68
GHz with respect to the atomic resonance. In contrast to previous measurements
the rotational splitting of the vibrational lines was fully resolved. Full
quantum mechanical numerical simulations of the photoassociation spectrum were
performed which allowed us to put constraints on the possible range of the
calcium scattering length to between 50 a_0 and 300 a_0
A scoring system for immunohistochemical staining: consensus report of the task force for basic research of the EORTC-GCCG
Samuel Beckettâs Krappâs Last Tape: Remembering Kant, Forgetting Proust
This article draws on Samuel Beckettâs recently published letters
and archival scholarship to consider the place of Immanuel Kantâs
critical epistemology within Beckettâs early thinking and his subsequent
works. Beginning from Beckettâs engagement with Kantâs Critique
of Pure Reason, demonstrated by notes taken from Wilhelm
Windelbandâs A History of Philosophy between 1932 and 1933, excerpts
from Jules de Gaultierâs From Kant to Nietzsche in the
âWhoroscopeâ Notebook, and Beckettâs acquisition of Immanuel
Kants Werke in 1938, I offer a close analysis of the philosophical underpinnings
of Beckettâs parody of Proustâs Ă la recherche du temps
perdu in Krappâs Last Tape. The larger purpose of this article is to
argue that a critique of metaphysical thought can be found in Beckettâs
work and to demonstrate that Kantâs influence as a philosophical
source of this critique has been largely overlooked in Beckett criticism
Influence of the vegetation management of the leeves in irrigated rice organic in diversity of Hymenoptera parasitoids
CinĂ©tica da degradação ruminal do capim TanzĂąnia irrigado sob trĂȘs nĂveis de resĂduo pĂłs-pastejo
Response of a Lake Michigan coastal lake to anthropogenic catchment disturbance
A paleolimnological investigation of post-European sediments in a Lake Michigan coastal lake was used to examine the response of Lower Herring Lake to anthropogenic impacts and its role as a processor of watershed inputs. We also compare the timing of this response with that of Lake Michigan to examine the role of marginal lakes as âearly warningâ indicators of potential changes in the larger connected system and their role in buffering Lake Michigan against anthropogenic changes through biotic interactions and material trapping. Sediment geochemistry, siliceous microfossils and nutrient-related morphological changes in diatoms, identified three major trophic periods in the recent history of the lake. During deforestation and early settlement (pre-1845â1920), lake response to catchment disturbances results in localized increases in diatom abundances with minor changes in existing communities. In this early phase of disturbance, Lower Herring Lake acts as a sediment sink and a biological processor of nutrient inputs. During low-lake levels of the 1930s, the lake goes through a transitional period characterized by increased primary productivity and a major shift in diatom communities. Post-World War II (late 1940sâ1989) anthropogenic disturbances push Lower Herring Lake to a new state and a permanent change in diatom community structure dominated by Cyclotella comensis . The dominance of planktonic summer diatom species associated with the deep chlorophyll maximum (DCM) is attributed to epilimnetic nutrient depletion. Declining Si:P ratios are inferred from increased sediment storage of biogenic silica and morphological changes in the silica content of Aulacoseira ambigua and Stephanodiscus niagarae . Beginning in the late 1940s, Lower Herring Lake functions as a biogeochemical processor of catchment inputs and a carbon, nutrient and silica sink. Microfossil response to increased nutrients and increased storage of biogenic silica in Lower Herring Lake and other regional embayments occur approximately 20â25Â years earlier than in a nearby Lake Michigan site. Results from this study provide evidence for the role of marginal lakes and bays as nutrient buffering systems, delaying the impact of anthropogenic activities on the larger Lake Michigan system.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/43091/1/10933_2004_Article_1688.pd
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