bluuebunny/crossref_metadata_2025 huggingface dataset:
The Neuropeptide Nociceptin Is a Synaptically Released Endogenous Inhibitor of Hippocampal Long-Term Potentiation
Authors: Bongsebandhu-phubhakdi Saknan , Manabe Toshiya
Published: May 2007

Hippocampal long-term potentiation (LTP) of excitatory synaptic transmission has been regarded as a cellular model of learning and memory. Its induction is regulated by many functional molecules at synapses, including the neuropeptide nociceptin, which is identified as an endogenous ligand for the orphan opioid receptor. Mutant mice lacking the receptor exhibit enhanced LTP and hippocampus-dependent memory formation; however, the precise molecular and cellular mechanism is largely unknown. Here, we show that LTP in the hippocampal CA1 region is inhibited by nociceptin synaptically released from interneurons by tetanic stimulation. This endogenous nociceptin downregulates the excitability of pyramidal cells by the hyperpolarization induced by the activation of K+channels, which are the common target shared with GABABreceptors, although the mode of action is considerably different. Interestingly, the modulation of LTP by endogenous nociceptin is not observed when theta-burst stimulation is used instead of tetanic stimulation, suggesting that relatively longer high-frequency synaptic activation is required for the release of endogenous nociceptin. These results indicate that, in addition to GABA, nociceptin released from interneurons by their high-frequency activation is a novel endogenous neuromodulator that negatively regulates LTP induction in the hippocampus through direct modulation of pyramidal cells.
PlexinA3 Restricts Spinal Exit Points and Branching of Trunk Motor Nerves in Embryonic Zebrafish
Authors: Feldner Julia , Reimer Michell M. , Schweitzer Jörn , Wendik Björn , Meyer Dirk , Becker Thomas , Becker Catherina G.
Published: May 2007

The pioneering primary motor axons in the zebrafish trunk are guided by multiple cues along their pathways. Plexins are receptor components for semaphorins that influence motor axon growth and path finding. We cloned plexinA3 in zebrafish and localized plexinA3 mRNA in primary motor neurons during axon outgrowth. Antisense morpholino knock-down led to substantial errors in motor axon growth. Errors comprised aberrant branching of primary motor nerves as well as additional exit points of axons from the spinal cord. Excessively branched and supernumerary nerves were found in both ventral and dorsal pathways of motor axons. The trunk environment and several other types of axons, including trigeminal axons, were not detectably affected by plexinA3 knock-down. RNA overexpression rescued all morpholino effects. Synergistic effects of combined morpholino injections indicate interactions of plexinA3 with semaphorin3A homologs. Thus, plexinA3 is a crucial receptor for axon guidance cues in primary motor neurons.
Conditional NF-L Transgene Expression in Mice forIn VivoAnalysis of Turnover and Transport Rate of Neurofilaments
Authors: Millecamps Stéphanie , Gowing Geneviève , Corti Olga , Mallet Jacques , Julien Jean-Pierre
Published: May 2007

We generated mice with doxycycline control of a human neurofilament light (NF-L) transgene in the context of the absence (tTA;hNF-L;NF-L−/−) or presence (tTA;hNF-L;NF-L+/−) of endogenous mouse NF-L proteins. Doxycycline treatment caused the rapid disappearance of human NF-L (hNF-L) mRNA in tTA;hNF-L mice, but the hNF-L proteins remained with a half-life of 3 weeks in the brain. In the sciatic nerve, the disappearance of hNF-L proteins after doxycycline treatment occurred in synchrony along the sciatic nerve, suggesting a proteolysis of NF proteins along the entire axon. The presence of permanent NF network in tTA;hNF-L;NF-L+/−mice further stabilized and extended longevity of hNF-L proteins by several months. Surprisingly, after cessation of doxycycline treatment, there was no evidence of leading front of newly synthesized hNF-L proteins migrating into sciatic nerve axons devoid of NF structures. The hNF-L proteins detected at weekly intervals reappeared and accumulated in synchrony at similar rate along nerve segments, a phenomenon consistent with a fast hNF-L transport into axons. We estimated the hNF-L transport rate to be of ∼10 mm/d in axons devoid of NF structures based on the use of an adenovirus encoding tet-responsive transcriptional activator to transactivate the hNF-L transgene in hypoglossal motor neurons. These results providein vivoevidence that the stationary NF network in axons is a key determinant of half-life and transport rate of NF proteins.
Modulation of the Purinergic P2X7Receptor Attenuates Lipopolysaccharide-Mediated Microglial Activation and Neuronal Damage in Inflamed Brain
Authors: Choi Hyun B. , Ryu Jae K. , Kim Seung U. , McLarnon James G.
Published: May 2007

We investigated the involvement and roles of the ionotropic purinergic receptor P2X7R in microglia in mediating lipopolysaccharide (LPS)-induced inflammatory responses and neuronal damage in rat striatum. A detailedin vivostudy showed that LPS injection into striatum markedly increased the expression of P2X7R in microglia compared with control (saline)-injected animals. Additionally, LPS injection upregulated a broad spectrum of proinflammatory mediators, including inducible nitric oxide synthase (nitric oxide production marker), 3-nitrotyrosine (peroxynitrite-mediated nitration marker), 4-hydroxynonenal (lipid peroxidation marker), and 8-hydroxy-2′-deoxyguanosine (oxidative DNA damage marker), and reduced neuronal viability. The P2X7R antagonist oxidized ATP (oxATP) was effective in attenuating expressions of all inflammatory mediators and in addition inhibited LPS-induced activation of the cellular signaling factors p38 mitogen-activated protein kinase and transcriptional factor nuclear factor κB. Most importantly,in vivo, oxATP blockade of P2X7R also reduced numbers of caspase-3-positive neurons and increased neuronal survival in LPS-injected brain.In vitro, LPS stimulation of cultured human microglia enhanced cellular expressions of a host of proinflammatory factors, including cyclooxygenase-2, interleukin-1β (IL-1β), IL-6, IL-12, and tumor necrosis factor-α; all factors were inhibited by oxATP. A novel finding was that LPS potentiated intracellular [Ca2+]imobilization induced by the P2X7R ligand 2′,3′-O-(4-benzoyl-benzoyl) ATP, which could serve as a mechanistic link for P2X7R amplification of inflammatory responses. Our results suggest critical roles for P2X7R in mediating inflammation and inhibition of this subtype purinergic receptor as a novel therapeutic approach to reduce microglial activation and confer neuroprotection in inflamed and diseased brain.
Serotonergic Modulation of Plasticity of the Auditory Cortex Elicited by Fear Conditioning
Authors: Ji Weiqing , Suga Nobuo
Published: May 2007

In the awake big brown bat, 30 min auditory fear conditioning elicits conditioned heart rate decrease and long-term best frequency (BF) shifts of cortical auditory neurons toward the frequency of the conditioned tone; 15 min conditioning elicits subthreshold cortical BF shifts that can be augmented by acetylcholine. The fear conditioning causes stress and an increase in the cortical serotonin (5-HT) level. Serotonergic neurons in the raphe nuclei associated with stress and fear project to the cerebral cortex and cholinergic basal forebrain. Recently, it has been shown that 5-HT2Areceptors are mostly expressed on pyramidal neurons and their activation improves learning and memory. We applied 5-HT, an agonist (α-methyl-5-HT), or an antagonist (ritanserin) of 5-HT2Areceptors to the primary auditory cortex and discovered the following drug effects: (1) 5-HT had no effect on the conditioned heart rate change, although it reduced the auditory responses; (2) 4 mm5-HT augmented the subthreshold BF shifts, whereas 20 mm5-HT did not; (3) 20 mm5-HT reduced the long-term BF shifts and changed them into short-term; (4) α-methyl-5-HT increased the auditory responses and augmented the subthreshold BF shifts as well as the long-term BF shifts; (5) in contrast, ritanserin reduced the auditory responses and reversed the direction of the BF shifts. Our data indicate that the BF shift can be modulated by serotonergic neurons that augment or reduce the BF shift or even reverse the direction of the BF shift. Therefore, not only the cholinergic system, but also the serotonergic system, plays an important role in cortical plasticity according to behavioral demands.
Constitutive Ret Activity in Knock-In Multiple Endocrine Neoplasia Type B Mice Induces Profound Elevation of Brain Dopamine Concentration via Enhanced Synthesis and Increases the Number of TH-Positive Cells in the Substantia Nigra
Authors: Mijatovic Jelena , Airavaara Mikko , Planken Anu , Auvinen Petri , Raasmaja Atso , Piepponen T. Petteri , Costantini Frank , Ahtee Liisa , Saarma Mart
Published: May 2007

Ret is the common signaling receptor for glial cell line-derived neurotrophic factor (GDNF) and other ligands of the GDNF family that have potent effects on brain dopaminergic neurons. The Met918Thr mutation leads to constitutive activity of Ret receptor tyrosine kinase, causing the cancer syndrome called multiple endocrine neoplasia type B (MEN2B). We used knock-in MEN2B mice with the Ret-MEN2B mutation to study the effects of constitutive Ret activity on the brain dopaminergic system and found robustly increased concentrations of dopamine (DA) and its metabolites in the striatum, cortex, and hypothalamus. The concentrations of brain serotonin were not affected and those of noradrenaline were slightly increased only in the lower brainstem. Tyrosine hydroxylase (TH) protein levels were increased in the striatum and substantia nigra/ventral tegmental area (SN/VTA), and TH mRNA levels were increased in SN/VTA of MEN2B mice, suggesting that constitutive Ret activity increases DA levels by increasing its synthesis. Also, the striatal DA transporter protein levels in the MEN2B mice were increased, which agrees with increased sensitivity of these mice to the stimulatory effects of cocaine. In the SN pars compacta of homozygous MEN2B mice, we found a 26% increase in the number of TH-positive cells, but no differences were found in the VTA. Thus, we show here that the constitutive Ret activity in mice is sufficient to increase the number of dopaminergic neurons and leads to profound elevation of brain DA concentration. These data clearly suggest that Ret activity per se can have a direct biological function that actively changes and shapes the brain dopaminergic system.
Extracellular proteins of Clostridium chauvoei are protective in a mouse model
Authors: Mattar María , Cortiñas Teresa , Stefanini Ana
Published: May 2007

The anaerobic bacillus
Clostridium chauvoei
is the causative agent of blackleg, a lethal disease that has an important impact on the sheep and cattle industry worldwide. Immunity to
C. chauvoei
is considered to be mainly anticellular, and for this reason there is scarce information about the immunogenicity of extracellular proteins. In this work variations in protein profiles, immune response by ELISA and protective capacity of culture supernatants of three
C. chauvoei
strains, collected at different growth phases, are reported. Sera raised against extracellular antigens also recognised cellular antigens of the same molecular masses. Partially purified cell-free supernatants and those concentrated 10 times by ultrafiltration (C-CFS), obtained at the early stationary phase of growth, induced a strong immunoprotective response, even at low doses, that was more marked for
C. chauvoei
strain ATCC 10092 (p ≤ 0.05). With C-CFS formulations, a clear relationship was observed between IgG titres, protective capacity and concentration of the antigen doses, indicating a specific immune response.
Effects of tiletamine-zolazepam anaesthesia on plasma antioxidative status and some haematological parameters in sheep
Authors: Ceylan C. , Aydilek N. , Ipek H.
Published: May 2007

It is not clear whether the anaesthetic agents tiletamine and zolazepam have antioxidant or pro-oxidant effects. Therefore, this study was carried out to investigate the effects of tiletamine-zolazepam anaesthesia on oxidant/antioxidant status in blood plasma and on haematological parameters in 10 healthy Awassi ewes. The tiletamine-zolazepam combination was administrated in a dose of 7.5 mg/kg intramuscularly. The animals were spontaneously breathing air during the procedure. Blood samples were collected by jugular venipuncture before induction and at 30, 60, 120 min, 24 h and 3 days after anaesthesia. Malondialdehyde concentration, an index of lipid peroxidation, was higher at 30, 60, 120 min and 24 h (P < 0.05) than the baseline value in the plasma. The level of glutathione decreased (P < 0.05) at 30, 60 and 120 min, then returned to the baseline level. Beta-carotene concentration was lower (P < 0.05) than the baseline value during anaesthesia with the exception of its level at 120 min. Glutathione peroxidase and catalase activities decreased (P < 0.05) at the onset of anaesthesia, then returned to baseline values. There was no significant change in vitamin A level. Red blood cell count, haematocrit and haemoglobin concentration significantly decreased (P < 0.05) only at 30 min and thereafter they gradually returned to the baseline values. Based on the results tiletamine-zolazepam anaesthesia seems to accelerate lipid peroxidation and to impair the enzymatic antixoidant defence in the blood plasma.
Detection of equine X chromosome mosaicism in a mare using an equine X whole chromosome painting probe (WCPP) — A case report
Authors: Bugno Monika , Słota Ewa , Pieńkowska-Schelling Aldona , Schelling C.
Published: May 2007

An infertile mare with hypoplastic ovaries was subjected to cytogenetic analysis. Fluorescence
in situ
hybridisation (FISH) using the equine X whole chromosome painting probe (WCPP) was carried out on a chromosome preparation obtained from blood lymphocyte culture. The number of analysed spreads was high (235) and in the X chromosome aneuploidy in mosaic form was diagnosed. The karyotype formula was 63,X / 64,XX / 65,XXX. The ratio of the three lines was 15%, 82% and 3%, respectively. The application of the FISH technique with WCPP is discussed.
Susac’s syndrome: clinical characteristics of a Hungarian case
Authors: Mike Andrea , Gaál Valéria , Németh Adrienne , Kövér Ferenc , Komoly Sámuel , Illés Zsolt
Published: May 2007

A Susac-szindróma ritka, többszörös szervi érintettséggel járó kórkép, melyet encephalopathiából, a retinát ellátó artéria ágainak okklúziójából és halláscsökkenésből álló triász jellemez. Ritka előfordulása, fluktuáló lefolyása és a hosszabb-rövidebb ideig inkomplett klinikai kép miatt sokszor nem ismerik fel, pedig az időben megkezdett kezelés a prognózist kedvezően befolyásolja.
Módszer:
Közleményünkben egy beteg esetét ismertetjük, és összefoglaljuk a kórkép legfontosabb ismérveit, diagnosztikai és terápiás lehetőségeit.
Eredmények:
A 30 éves nőbeteg ismeretlen eredetű encephalopathia, napok alatt kialakuló személyiségváltozás, meglassult gondolkodás, indítékhiány miatt került a pszichiátriai, majd a neurológiai klinikánkra. A koponya MR-vizsgálata multiplex fehérállományi laesiókat, liquorvizsgálata emelkedett összfehérjét mutatott. Az anamnézisben szereplő ismétlődő kétoldali látászavar, halláscsökkenés és migrénes fejfájás az encephalopathiával együtt a fiatal nőbeteg esetében Susac-szindróma lehetőségét vetette fel. Az immunszerológiai vizsgálatok szisztémás kötőszöveti betegséget nem jeleztek, a thrombophilia irányában végzett vizsgálatok negatívak voltak. A fundoszkópia és a fluoreszcens angiográfia a retinaerek többszörös okklúzióját, az audiogram kétoldali típusos halláscsökkenést mutatott. A liquor vizsgálata a szindrómára jellemző összfehérje-emelkedést jelezte. A krónikus szteroidterápia a tünetek regresszióját eredményezte.
Következtetések:
Egy magyar eset ismertetésével célunk ráirányítani a figyelmet egy olyan ritka kórképre, melynél az interdiszciplináris gondolkodás a klinikai diagnózis alapvető része.
Optimal Stocking Densities of Walleye Fingerlings in Minnesota Lakes
Authors: Jacobson Peter C. , Anderson Charles S.
Published: May 2007

A generalized additive model was developed that described the effects of fingerling stocking density on the abundance of walleyes Sander vitreus in 551 lakes in Minnesota. Walleye abundance was measured as a catch per effort (CPE) from 1,511 standard Minnesota Department of Natural Resources gill-net assessments conducted during 1986–2004. In addition to fingerling stocking, the effects of lake morphometry, productivity, and fish community variables on walleye CPE were also described using a generalized additive model. Lake morphometry variables had sharply nonlinear effects on walleye abundance. Walleye abundance declined in lakes with areas less than 1,000 acres and increased rapidly in lakes with depths of less than 30 ft. The lake productivity variable, total alkalinity, was positively related to walleye abundance. Abundance of northern pike Esox lucius had a negative effect and abundance of yellow perch Perca flavescens a positive effect on walleye abundance. The response of walleye abundance to fingerling stocking was asymptotic: peak walleye abundance occurred at stocking densities greater than 0.65 lb·littoral acre−1·year−1. A fingerling stocking density of 0.50 lb·littoral acre−1·year−1 is recommended as a balance between increased abundance and relative costs of stocking for most lakes in Minnesota.
Production of External Fluorescent Marks on Golden Perch Fingerlings through Osmotic Induction Marking with Alizarin Red S
Authors: Crook David A. , O'Mahony Damien , Gillanders Bronwyn M. , Munro Andrew R. , Sanger Andrew C.
Published: May 2007

Osmotic induction marking trials with alizarin red S (ARS) were conducted on golden perch Macquaria ambigua to evaluate the use of ARS as a lower-cost alternative to osmotic induction marking with calcein for producing external fluorescent marks on hatchery-produced fish. After a 10-min immersion in a 5% solution of salt, experimental groups of golden perch were rinsed for 5 s in freshwater and immersed for 10 min in either a 0.1% or 0.5% solution of ARS, whereas control groups were either left untreated or immersed in a 0.1% solution of ARS for 10 min without prior immersion in the salt solution. All fish treated in the 0.5% solution of ARS died within 5 min of immersion, but no mortalities were observed in any of the controls or fish treated with the 0.1% solution of ARS. External fluorescent marks were observed on both the osmotic induction-marked fish and the direct ARS immersion-marked fish 100 d after treatment, but the osmotic induction-marked fish possessed more intense marks. Clear marks remained visible on fish marked by osmotic induction 9 months after treatment. This study indicates that highly visible external marks can be produced through osmotic induction with ARS at a substantially lower cost than marks produced through osmotic induction with calcein. Although further refinement and testing are needed, we conclude that the method has considerable potential for use in the mass marking of fish.
Precision of Hard Structures Used to Estimate Age of Riverine Catostomids and Cyprinids in the Upper Colorado River Basin
Authors: Quist Michael C. , Jackson Zachary J. , Bower Michael R. , Hubert Wayne A.
Published: May 2007

Understanding the population dynamics of native and nonnative fishes is critical for guiding and evaluating management activities, but obtaining information on population dynamics is often dependent on identifying structures that provide precise estimates of age. We examined age estimation using various hard structures for native bluehead suckers Catostomus discobolus, flannelmouth suckers C. latipinnis, and roundtail chub Gila robusta, and nonnative white suckers C. commersonii, creek chub Semotilus atromaculatus, white sucker × bluehead sucker hybrids, and white sucker × flannelmouth sucker hybrids in a small headwater stream of the upper Colorado River basin (UCRB) in Wyoming. We evaluated between-reader precision (i.e., between two readers) and agreement of otolith age estimates with estimates from scales, fin rays, cleithra, and opercular bones. Exact agreement between readers was highest for otoliths (66–96% among species) and fin rays (61–92%) and lowest for opercles (25–69%), cleithra (21–41%), and scales (15–48%). Age estimates from fin rays were almost exactly the same as those from otoliths for all species except creek chub, for which fin ray estimates were consistently lower than otolith estimates. Age estimates from scales were generally 1–4 years lower than those from otoliths for most species, and most discrepancies occurred when otolith ages were greater than 5 years. We recommend that fin rays be used to estimate age of native catostomids and roundtail chub in the UCRB because fin rays provide accurate estimates of otolith age and can be obtained without sacrificing fish. We further recommend that otoliths be used to estimate age of creek chub in the UCRB because accuracy of fin rays was poor and because sacrificing this nonnative species may benefit native fishes of the UCRB.
A Comparison of Shoreline Seines with Fyke Nets for Sampling Littoral Fish Communities in Floodplain Lakes
Authors: Clark Sandra J. , Jackson John R. , Lochmann Steve E.
Published: May 2007

We compared shoreline seines with fyke nets in terms of their ability to sample fish species in the littoral zone of 22 floodplain lakes of the White River, Arkansas. Lakes ranged in size from less than 0.5 to 51.0 ha. Most contained large amounts of coarse woody debris within the littoral zone, thus making seining in shallow areas difficult. We sampled large lakes (>2 ha) using three fyke nets; small lakes (<2 ha) were sampled using two fyke nets. Fyke nets were set for 24 h. Large lakes were sampled with an average of 11 seine hauls/lake and small lakes were sampled with an average of 3 seine hauls/lake, but exact shoreline seining effort varied among lakes depending on the amount of open shoreline. Fyke nets collected more fish and produced greater species richness and diversity measures than did seining. Species evenness was similar for the two gear types. Two species were unique to seine samples, whereas 13 species and 3 families were unique to fyke-net samples. Although fyke nets collected more fish and more species than did shoreline seines, neither gear collected all the species present in the littoral zone of floodplain lakes. These results confirm the need for a multiple-gear approach to fully characterize the littoral fish assemblages in floodplain lakes.
Influences on Brown Trout and Brook Trout Population Dynamics in a Michigan River
Authors: Zorn Troy G. , Nuhfer Andrew J.
Published: May 2007

Understanding the influences of local and regional processes on the dynamics of self‐sustaining trout populations would help fishery biologists better manage trout populations and protect rivers supporting trout. We explored hypotheses behind long‐term temporal variation in density, growth, and survival of brown troutSalmo truttaand brook troutSalvelinus fontinalisusing data collected over several decades on Michigan's Au Sable River. Regression models developed for these species emphasized the influence of year‐class strength on older age‐classes, year‐class strength being positively related to spawner abundance for both species and negatively related to high spring streamflow conditions for brown trout. Age‐class density was also positively associated with high levels of large woody debris (LWD) in streams. Annual growth increments of brown trout and brook trout were often negatively related to increased age‐class density and LWD and positively affected by elevated total phosphorus levels, cool summers, and warm winters. Annual survival of trout from age 0 to age 4 was negatively related to intra‐ and interspecific age‐class density, and in three of seven models, positively associated with levels of LWD. Our findings emphasize the importance of year‐class strength to trout population dynamics as well as the need to include collection of regional‐ and local‐scale habitat data in studies of trout population dynamics.
Regional Synchrony of Brown Trout and Brook Trout Population Dynamics among Michigan Rivers
Authors: Zorn Troy G. , Nuhfer Andrew J.
Published: May 2007

The ability to describe regional patterns in trout density would be useful for biologists concerned with population status across large regions as well as managers of rivers at the local scale. Noting the importance of flow conditions at the time of emergence to trout year‐class strength in Michigan streams and the influence of age‐0 trout abundance on subsequent abundance of older age‐classes, we assessed the potential for regional synchrony in the population dynamics of brown trout Salmo trutta and brook trout Salvelinus fontinalis among Michigan rivers. We used correlation analyses to look for regional synchrony in May stream discharge (approximating the time of brown trout fry emergence) and fall trout density among many Michigan trout streams. We found a high degree of synchrony in average May discharge among streams, particularly those in the northern portion of Michigan's Lower Peninsula. There were significant correlations in the long‐term densities of brown trout and brook trout year‐classes among several rivers in this area, including sites up to 140 km apart and rivers draining into different Great Lakes. Predicted numbers of days to 50% swim‐up of brown trout fry were similar among four streams and synchronous, further supporting the hypothesis of synchrony in trout population dynamics in Michigan streams at the regional scale. Long‐term trout population estimates and streamflow data collected from a network of long‐term index (fixed) sites throughout Michigan will aid in further description of the spatial extent of synchrony in trout populations.
Biomechanics of ossified tendons in ornithopod dinosaurs
Authors: Organ Chris L.
Published: May 2007

Spinal ossified tendons are a defining character for Ornithischia, one of the two major clades of dinosaurs. The function of these bony rods has remained a mystery since their first detailed description in 1886. Qualitative approaches to understand ossified tendon function have resulted in different ecological and behavioral interpretations for ornithopod dinosaurs. To evaluate ossified tendon function, this study constructed finite element models of the vertebral column for two ornithopod taxa:Tenontosaurus, which shows the plesiomorphic condition of longitudinally arrayed tendons along the spinous processes, andBrachylophosaurus, which exhibits a lattice of tendons along the spinous processes. Both models predict that ossified tendons stiffened the vertebral column, especially the tail, but the derived lattice of ossified tendons in iguanodontoidean dinosaurs, likeBrachylophosaurus, increased spinal stiffness more than the plesiomorphic condition. Caudofemoral muscles that retracted the hindlimb during locomotion attached the femur to the tail in ornithopods. Increased tail stiffness caused by intratendinous ossification may have influenced locomotion by rigidly anchoring M. caudofemoralis longus to the tail, thereby allowing a more forceful retraction of the hindlimb by reducing ventral flexion of the tail during muscle contraction. Ossified tendons may also have been important for storing elastic energy throughout the gait cycle. Moreover, the lattice of ossified tendons stiffened the trunk and tail nearly equally inBrachylophosaurus, indicating the evolution of a postural function by passively supporting the epaxial musculature in maintaining a horizontal vertebral column.
Varieties of Capitalism and the Auto Industry's Environmental Initiatives: National Institutional Explanations for Firms' Motivations
Authors: Mikler John J.
Published: May 2007

The auto industry is usually considered to be a global industry. Yet the majority of passenger cars are still manufactured and sold in industrialised states where its largest firms are headquartered. The central claim made is that despite the auto industry being comprised of multinational corporations, there are clear national differences in the motivations firms cite for environmental initiatives. US firms are more focused on traditional material factors, especially market forces. However, German and Japanese firms are more focused on social concerns and internally-driven strategies. They have more normative, non-market rationales for their environmental initiatives. By analysing what firms themselves say motivates them to improve the environmental performance of their products, via a qualitative analysis of recent environmental reports by German, US and Japanese firms, as well as interviews conducted with key personnel, the conclusion reached is as follows. While the question of ‘greenwashing’ versus real commitment to reduce the environmental impact of the industry's products remains relevant, the institutional basis of capitalist relations in their home state (i.e. their home state's variety of capitalism) suggests different nationally appropriate and conducive paths to environmental commitments.
Field Experiments: A Bridge between Lab and Naturally Occurring Data
Authors: List John A.
Published: May 2007

Laboratory experiments have been used extensively in economics in the past several decades to lend both positive and normative insights into a myriad of important economic issues. This study discusses a related approach that has increasingly grown in prominence of latefield experiments. I argue that field experiments serve as a useful bridge between data generated in the lab and empirical studies using naturally-occurring data. In discussing this relationship, I highlight that field experiments can yield important insights into economic theory and provide useful guidance to policymakers. I also draw attention to an important methodological contribution of field experiments: they provide an empirical account of behavioral principles that are shared across different domains. In this regard, at odds with conventional wisdom, I argue that representativeness of the environment, rather than representative of the sampled population, is the most crucial variable in determining generalizability of results for a large class of experimental laboratory games.
Curing Spam: Rights, Signals & Screens
Authors: Van Alstyne Marshall W.
Published: May 2007

Recognizing spam as a pollution problem points to a market-based approach that could be more effective than prior approaches based on technology or law. Marshall Van Alstyne argues that an imperfect market could create more value than even a hypothetical "perfect" filter.
Garrison America
Authors: Bowles Samuel , Jayadev Arjun
Published: May 2007

Samuel Bowles and Arjun Jayadev estimate that America devotes about a quarter of its labor force to conflicts over dividing up the pie rather than producing it--far more than other nations. Inequality may be among the reasons.
Corporate Attorney-Client Privilege: Who Represents the Corporation?
Authors: Baum Ido
Published: May 2007

The corporate lawyer-client privilege is increasingly controversial. Courts assert that the privilege promotes corporate compliance with the law as long as it is restricted to communications in furtherance of legal advice. This article assumes the privilege increases the probability that a corporation will escape liability. Courts can apply various tests to determine whether the agent who communicated with the corporate attorney can be defined as a representative of the corporation. The most restrictive test, the “control group” test, has been rejected by most American jurisdictions, but it has recently re-emerged in the United Kingdom. The author proposes that this test motivates corporations to restructure their optimal internal decision-making processes in order to “squeeze” into the privilege. When plaintiffs are uninformed about the internal organization of a corporate defendant, even corporations that cannot squeeze into the test have an incentive to mimic the behavior of privileged corporations, and consequently pursue socially harmful actions. These findings are supported by case law from control group jurisdictions.
Pork Quality Classification Using a Hyperspectral Imaging System and Neural Network
Authors: Jun Qiao , Ngadi Michael , Wang Ning , Gunenc Aynur , Monroy Mariana , Gariepy Claude , Prasher Shiv
Published: May 2007

Pork quality is usually determined subjectively as PSE, PFN, RFN, RSE and DFD based on color, texture and exudation of the meat. In this study, a hyperspectral-imaging-based technique was developed to achieve rapid, accurate and objective assessment of pork quality. The principal component analysis (PCA) and stepwise operation methods were used to select feature waveband from the entire spectral wavelengths (430 to 980 nm). Then the feature waveband images were extracted at the selected feature wavebands from raw hyperspectral images, and the average reflectance (R) was calculated within the whole loin-eye area. Artificial neural network was used to classify these groups. Results showed that PCA analysis had a better performance than that of stepwise operation for feature waveband images selection. The 1st derivative data gave a better result than that of mean reflectance spectra data. The best classified result was 87.5% correction. The error frequency showed that RSE samples were easier to classify. The PFN and PSE samples were difficult to separate from each other.
Semiempirical Fouling Kinetics Model in Batch and Continuous Direct Ohmic Heating of Milk
Authors: ulc Radek , Nový Michal
Published: May 2007

The direct ohmic heating has been one of modern heating technology at which an electrical current passing directly through an electrically conductive medium generates the heat. During milk ohmic heating fouling deposits can be formed due to milk protein degradation. The fouling removal requires periodical cleaning that increases costs of energy, detergents and wastewater treatment.Simple semiempirical generalized correlation quantifying the effect of concentration and temperature onto electrical conductivity was proposed and tested on published data of milk, coffee and aqueous H2TiF6 solution. The semiempirical fouling kinetics model was proposed and verified in direct batch ohmic heating of milk. The model is based on the analogy to mechanisms and chemical kinetics of serial reactions. The effect of flowrate onto the fouling formation in continuous direct ohmic heating of milk was investigated. The proposed empirical fouling kinetics model is based on the assumption that the growth rate of the fouling layer thickness depends on time exponentially. It was found that fouling layer growth intensity was not decreased by the higher wall shear stress induced by the higher flowrate. However increasing wall shear stress enlarged the maximal time tnf in which the fouling layer growth is negligible.
Spatial and Temporal Resolution in Data-Driven Process Modeling of an Integrated Newsprint Mill
Authors: Harrison Robert P , Stuart Paul
Published: May 2007

Like many globalized industries, the pulp and paper sector finds itself with an increasingly demanding clientele, who continually expect a better and cheaper product. An important design strategy being employed to address this objective is through an analysis of the vast quantity of process and product data accumulated in plant-wide data historians, in order to improve operations. Mill processes are multivariate, meaning that the interactions between the variables are as important as the variables themselves. Process relationships must therefore be modeled as a group, using an appropriate simulation technique like Multivariate Analysis (MVA), with suitable data pre-processing to account for process upsets and other disturbances. In a previous paper, using an Eastern Canadian newsprint mill as an industrial case study, we showed that it was possible to find statistically significant correlations between wood chip refiner operation, intermediate pulp quality, and final paper quality using data-driven models. This was true even though some important process parameters went unmeasured, process lags changed with time, and the operation of key equipment items changed gradually with use. The present study compares the use of different timescales and combinations of unit operations to determine which ones yield the best MVA simulations. Because plant operating data were used, and experimental design was not practical, it is possible that some of the correlations found could be attributable to coincidence. We therefore added and removed variables and time periods to explore the validity of the models. The best MVA models were obtained by using a shorter (1-hour) data timescale, although use of a weighted-average filter helped to bridge the gap between these faster readings and the slower paper quality trends.
Optimization of the Variable Reflux Ratio in a Batch Distillation Column through a Heuristic Method
Authors: Manca Davide
Published: May 2007

The manuscript is focused on the optimization of a batch distillation column that is actually formulated in terms of control problem. The final objective is finding the optimal time-dependent reflux profile. In order to fulfill the call for simplicity and functionality from the industries, the reflux profile was approximated by means of a piece-wise function with three time intervals. A first-principles model, derived from the literature, proved to be a good trade-off between computational effort and accuracy. The capacity factor (CAP), defined as the on-specification products produced per time unit, is the performance index that must be maximized. The optimization problem was solved by a specifically modified Simplex method that demonstrated a good behavior in case of discontinuous objective function. Finally, a graphical analysis of the capacity factor was performed to show the irregularities of such a function.
Entry Deterrence in a Duopoly Market
Authors: Dana James D. , Spier Kathryn E.
Published: May 2007

In a homogeneous good, Cournot duopoly model, entry may occur even when the potential entrant has no cost advantage and no independent access to distribution. By sinking its costs of production before negotiating with the incumbents, the entrant creates an externality that induces the incumbents to bid more aggressively for the distribution rights to its output. Each incumbent is willing to pay up to the incremental profit earned from the additional output plus the incremental loss avoided by keeping the output away from its rival. This implies that the incumbents are willing to pay up to the market price for each unit of available output. A sequential game in which the incumbents produce first is analyzed, and the conditions under which entry is deterred by incumbents' preemptive capacity expansions are derived.
Mimicking History: The European Commission and Its Education Policy
Authors: Petit Isabelle
Published: May 2007

Decision makers do not act in a policy vacuum. As they develop their programs, they are aware of and influenced by available historical examples. If we look closely at the European Commission's education policy (measures as well as discourses), we notice the existence of similarities in the strategies that it deploys in this field and dynamics deployed much earlier by states engaged in nation building (that is, the redefinition of peoples' spatial representation of their community of belonging; the creation of a framework of shared values; and the process of "detemporalization-naturalization").This observation leads us to believe that if the European Commission decided to become involved in the field of education at an early stage in the integration process, it was not onlyas most people believeto ensure an effective implementation of the Common Market in 1957 or the Single Market in 1987. Rather, through its education policy, the Commission also hoped to create and foster an EU identity that the founding fathers and subsequent "Europeans" considered necessary for achieving their goals of creating "an ever closer union."
Strategy, Relevance and Meaning: On the Use of Context in the Finnish European Elections 2004
Authors: Mykkanen Juri
Published: May 2007

In this article Relevance Theory, a variety of cognitive linguistics, is applied to televised political advertising, extending the theory to cover audiovisual communication besides its traditional use in studying verbal communication. According to Relevance Theory signification in any communicated message is more complicated than the standard semiotic theory claims. More profound mental processes must take place prior to the moment of perceiving the message as composed of coded elements. With examples drawn from the Finnish campaign for the 2004 European Parliamentary elections, the article shows how these prior mental processes operate to produce the appearance of coded messages. To understand how relevance works, it is important to pay close attention to strategies applied by campaign teams in creating TV spots. It is also argued that relevance theory, better than semiotics, can be used in bridging political advertising and political practice and upgrading the status of political advertising as a serious art of politics.
Digital Media Literacies: Rethinking Media Education in the Age of the Internet
Authors: Buckingham David
Published: May 2007

This article considers how media educators can respond to the new challenges and opportunities of the Internet, and of digital media more broadly. It begins by exploring the value and limitations of the notion of ‘literacy’ in this context. It argues that ‘competence-based’ definitions of literacy tend to neglect the social diversity of literacy practices, and to retain a narrow focus on ‘information’, and it suggests that a broader definition of literacy necessarily entails a more critical approach. It then moves on to consider the nature of digital literacy more specifically. It argues that definitions of digital literacy have tended to take a rather limited view of information, and of issues of reliability and bias, and it proposes a broader approach which recognises the social and ideological nature of all forms of mediated representation. Following from this, it then provides some concrete indications of ways in which media education approaches might be applied specifically to the analysis of the World Wide Web, using the established framework of ‘key concepts’ (representation, language, production, audience). Finally, it considers the potential of digital media production in the classroom as a means of promoting digital literacy. It distinguishes between the approach adopted by media educators and more instrumental or expressive approaches. It then considers the difficulties of such work in a context where a ‘digital divide’ in access to technology continues to exist, both within and between societies. It argues that the benefits of digital technology in this respect depend crucially on the pedagogic and social contexts in which such technology is used, for example, in the opportunities that are provided for collaborative production and for students sharing their work with a wider audience. The article concludes by arguing that digital literacy needs to be seen as part of a broader reconceptualisation of literacy, and of the use of technology in education.
Argumentative Knowledge Construction in Online Learning Environments in and across Different Cultures: A Collaboration Script Perspective
Authors: Weinberger A. , Clark D.B. , HÄkkinen P. , Tamura Y. , Fischer F.
Published: May 2007

In recent years, information and communication technology has established new opportunities to participate in online learning environments around the globe. These opportunities include the dissemination of specific online learning environments as well as opportunities for learners to connect to online learning environments in distant locations. These dissemination and distance learning scenarios create potential challenges, however, in terms of the cultural differences in the internal scripts that learners of different cultures bring to these environments. This article considers these issues and challenges specifically for online environments focusing on argumentative knowledge construction. It discusses the importance of cross-cultural research in this area and proposes that a collaboration script perspective may prove extremely valuable for this research.
Pyrrole thin films deposited on paper by pulsed RF plasma
Authors: Şahin Halil
Published: May 2007

Attempts were made to plasma deposit an oriented π-conjugated polymer of pyrrole (Py) on paper surfaces in order to produce electrically conductive layers. The N/C atomic ratio of 0.13–0.24 was observed for all treatment conditions. This implies the nature of the deposition formed on the paper surface via pulsed plasma is different from that of pyrrole monomer. An increase in conductivity of all pyrrole-plasma treated papers was observed. The 50 W RF-power with 5 min plasma exposed paper sample shows 8.15 × 10−9 S·cm−1 conductivity. The conductivity measurements indicated a plasma-enhanced ring-opening reaction mechanism of pyrrole.
Physical Foundations of Rhenium-Osmium Method - A Review
Authors: Dąbek Józef , Halas Stanislaw
Published: May 2007

A newly acquired mass spectrometer MI 1201 by the Mass Spectrometry Laboratory will be adapted to determine rhenium and osmium isotope concentrations using negative thermal ionization mass spectrometry (NTIMS). We describe the principle of the Re-Os dating technique and the thermal ionization phenomena which lead to high precision isotope analysis on NTIMS.
Glacial and Periglacial Transformation of Palaeokarst in the Lublin-Volhynia Region (Se Poland, NW Ukraine) on the Base of TL Dating
Authors: Dobrowolski Radosław , Fedorowicz Stanisław
Published: May 2007

Distinctly diverse results of TL dating are obtained for the deposits with similar lithofacial features but filling morphologically differentiated karst palaeoforms (dolines, pipes, pockets). The infillings of dolines and pipes are mostly of the Saalian age. Based on sedimentological analysis, their formation conditions are related to sub- or/and terminoglacial environment. The age obtained for all infillings of pockets is underestimated in comparison with lithostratigraphic data. A close genetic relationship between these forms and periglacial conditions seems to indicate that the reduction of TL signal is mostly influenced by the disintegration of grains resulted from the repeated freezing and thawing of glaciogenic deposits. A considerable influence of frost weathering on the decrease of thermoluminescence intensity of mineral grains is indirectly confirmed by the results of experimental investigations consisting in the repeated TL measurements of pockets' infillings after successive freeze-thaw cycles.
Age Correlation of Loess with other Pleistocene Deposits on the Basis of TL and OSL Dating
Authors: Fedorowicz Stanisław
Published: May 2007

The author collected 26 samples from six loess profiles located in Poland and Ukraine and 16 samples from three galcigenic profiles in Lithuania. TL and OSL dates were obtained for the samples. The TL dates were calculated in the Gdańsk University laboratory and the OSL dates were obtained by the Institute of Physics Laboratory at the Silesian Technical University. The dating results were referred to the OSL = f(TL) chart. In respect of luminescent dating results, the Upper Vistulian loess shows a high similarity of TL and OSL dates. It means that loess formation took place in conditions conductive to ensure that solar radiation the grains were exposed to reduce the energy accumulated in them. The TL dates of Middle and Upper Vistulian loess are slightly older than the OSL dates. The largest discrepancies were found in soil sample dates. The analysis of glacigenic profile dates is not unambiguous. The fact that the TL dates are older than the OSL dates may mean that during deposition the conditions were not sufficiently conductive to reduce the energy stored earlier in the grains examined with the TL method. This time could have been sufficient to reduce the energy examined with the OSL method.