33,548 research outputs found
Ocean shrimp report 1972 season
California's 1972 ocean shrimp landings totaled 2,488,683 pounds, a decrease of 585,857 pounds from the 1971 season when 3,074,540 pounds were landed. The decrease resulted primarily from the failure of the vessels to reach the quotas in Areas A, B-1 and B-2. (18pp.
Recovery operators, paraconsistency and duality
There are two foundational, but not fully developed, ideas in paraconsistency, namely, the duality between paraconsistent and intuitionistic paradigms, and the introduction of logical operators that express meta-logical notions in the object language. The aim of this paper is to show how these two ideas can be adequately accomplished by the Logics of Formal Inconsistency (LFIs) and by the Logics of Formal Undeterminedness (LFUs). LFIs recover the validity of the principle of explosion in a paraconsistent scenario, while LFUs recover the validity of the principle of excluded middle in a paracomplete scenario. We introduce definitions of duality between inference rules and connectives that allow comparing rules and connectives that belong to different logics. Two formal systems are studied, the logics mbC and mbD, that display the duality between paraconsistency and paracompleteness as a duality between inference rules added to a common core– in the case studied here, this common core is classical positive propositional logic (CPL + ). The logics mbC and mbD are equipped with recovery operators that restore classical logic for, respectively, consistent and determined propositions. These two logics are then combined obtaining a pair of logics of formal inconsistency and undeterminedness (LFIUs), namely, mbCD and mbCDE. The logic mbCDE exhibits some nice duality properties. Besides, it is simultaneously paraconsistent and paracomplete, and able to recover the principles of excluded middle and explosion at once. The last sections offer an algebraic account for such logics by adapting the swap-structures semantics framework of the LFIs the LFUs. This semantics highlights some subtle aspects of these logics, and allows us to prove decidability by means of finite non-deterministic matrices
Packet equalisation in PONs using adjustable gain-clamped semiconductor optical amplifiers (AGC-SOA)
The past ten years have witnessed a dramatic growth in the delivery of high bandwidth services through Passive Optical Networks (PONs), directly to the home or to the kerb. The bursty nature of upstream traffic in a PON (from the user to Optical Network Unit, ONU) combined with a wide dynamic range of signal strength (-15dB to -28dB the difference between a very close Optical Network Terminal (ONT) with a small split ratio and a distant ONT with a high split ratio), places severe demands on the burst mode receiver at the ONU. We report here on an adjustable gain-clamped semiconductor optical amplifier (AGC-SOA) designed to maximize the output saturated power while adjusting gain to regulate the power differences between packets without loss of linearity. This device is shown to be able to modulate gain at rates that are compatible with packet to packet equalisation. Through theoretical analysis coupled with experimental verification, this paper demonstrates for the first time that this is entirely feasible
Import of cytochrome c heme lyase into mitochondria
Cytochrome c heme lyase (CCHL) catalyses the covalent attachment of the heme group to apocytochrome c during its import into mitochondria. The enzyme is membrane-associated and is located within the intermembrane space. The precursor of CCHL synthesized in vitro was efficiently translocated into isolated mitochondria from Neurospora crassa. The imported CCHL, like the native protein, was correctly localized to the intermembrane space, where it was membrane-bound. As with the majority of mitochondrial precursor proteins, CCHL uses the MOM19-GIP receptor complex in the outer membrane for import. In contrast to proteins taking the general import route, CCHL was imported independently of both ATP-hydrolysis and an electrochemical potential as external energy sources. CCHL which lacks a cleavable signal sequence apparently does not traverse the inner membrane to reach the intermembrane space; rather, it translocates through the outer membrane only. Thus, CCHL represents an example of a novel, 'non-conservative' import pathway into the intermembrane space, thereby also showing that the import apparatus in the outer membrane acts separately from the import machinery in the inner membrane
Market Structure in the Residential Real Estate Brokerage Market
This study provides empirical evidence regarding brokerage firm concentration in a local market multiple listing service setting over the year 1992-1995. To evaluate the level of brokerage firm concentration in this market, Gini Coefficients, Herfindahl-Hirschman Indices and Concentration Ratios for each year of the study period are calculated. Our results indicate that for firms responsible for listing properties, firm concentration has not varied substantially over the four-year study period. However, for those firms that were responsible for actually selling properties, firm concentration has decreased over the study period. This finding tends to indicate that the MLS now provides greater exposure to a wide variety of sales firms, therefore leading to a higher level of competition with a lower level of concentration for selling firms in this local market.
Low Molecular Weight mRNA Encodes a Protein That Controls Serotonin 5-HT_(1c) and Acetylcholine M_1 Receptor Sensitivity in Xenopus Oocytes
Serotonin 5-HT_(1c) and acetylcholine M_1 receptors activate phosphoinositidase, resulting in an increased formation of IP_3 and 1,2 diacylglycerol. In Xenopus oocytes injected with mRNA encoding either of these receptors, Ca^(2+) released from intracellular stores in response to IP3 then opens Ca^(2+)-gated Cl^-channels. In the present experiments, oocytes expressing a transcript from a cloned mouse serotonin 5-HT_(1c) receptor were exposed to identical 15-s pulses of agonist, administered 2 min apart; the second current response was two to three times that of the first. However, in those oocytes coinjected with the 5-HT_(1c) receptor transcript and a low molecular weight fraction (0.3-1.5 kb) of rat brain mRNA, the second current response was ~50% of the first. Thus, the low molecular weight RNA encodes a protein (or proteins) that causes desensitization. Experiments using fura-2 or a Ca^(2+)-free superfusate indicated that desensitization of the 5-HT_(1c) receptor response does not result from a sustained elevation of intracellular Ca^(2+) level or require the entry of extracellular Ca^(2+). Photolysis of caged IP_3 demonstrated that an increase in IP_3 and a subsequent rise in Ca^(2+) do not produce desensitization of either the IP_3 or 5-HT_(1c) peak current responses. Furthermore, in oocytes coinjected with the low molecular weight RNA and a transcript from the rat M_1 acetylcholine receptor, the M_1 current response was greatly attenuated. Our data suggest that the proteins involved in attenuation of the M_1 current response and desensitization of the 5-HT_(1c) current response may be the same
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