bluuebunny/crossref_metadata_2025 huggingface dataset:
Effects of Mycosphaerella leaf disease on the spectral reflectance properties of juvenile Eucalyptus globulus foliage
Authors: Pietrzykowski E. , Stone C. , Pinkard E. , Mohammed C.
Published: September 2006

Mycosphaerella leaf disease (MLD) can cause significant discoloration, necrosis and defoliation in commercial plantations of young Eucalyptus globulus. This study investigated the spectral reflectance changes that result in E. globulus foliage from Mycosphaerella infection. Spectral reflectance measurements were made on healthy and infected E. globulus foliage in the visible and near‐infrared wavelengths (400–1000 nm). Reflectance (R) at 760 nm produced the largest difference between the extremes of disease severity classes. The wavelength most sensitive to infection severity was R678 nm. Other sensitive wavelengths were located between 480 and 500 nm. The wavelengths near 708 and 550 nm appeared relatively insensitive to infection severity. The reflectance index best correlated to leaf infection was R678/R550 (r = 0.841, p < 0.0001). This index was used in a linear regression model for successfully predicting leaf infection levels from an independent data set (r = 0.95, p < 0.0001).
The sporicidal activity of yellow‐cedar heartwood, essential oil and wood constituents towards Phytophthora ramorum in culture
Authors: Manter D. K. , Karchesy J. J. , Kelsey R. G.
Published: September 2006

In this paper, we demonstrate that 140 mg/kg of essential oil from the wood of yellow‐cedar, incense cedar, Port‐Orford‐cedar or western juniper strongly inhibits zoospore germination and hyphal growth of Phytophthora ramorum in culture. Four individual compounds in yellow‐cedar heartwood were also tested. Zoospore germination was reduced to 0% with 10, 100 and 1000 mg/kg of nootkatin, carvacrol and valencene, respectively. Nootkatone was the least active compound, with 3.5% zoospore germination at 1000 mg/kg. Sporangia germination was 0% with 500 mg/kg of nootkatin or carvacrol. The disruption of the zoospore outer membrane and the loss of sporangial contents were often observed and indicative of sporicidal activity. Hyphal growth was inhibited by 99.9% with 50 mg/kg of nootkatin or 500 mg/kg of carvacrol, but growth resumed upon removing the inhibitors. The zoosporicidal activity of yellow‐cedar heartwood shavings stored dry for approximately 10 years was consistent with the quantity of extractable compounds they contained. Thus, spreading fresh shavings or chips of yellow‐cedar heartwood with appreciable higher concentrations of the active compounds, over areas in infection zones where spores might be difficult to control such as trails and parking lots used by hikers and bicyclists, might be useful as part of an integrated program to minimize P. ramorum spore distribution.
Records of Bursaphelenchus spp. intercepted in imported packaging wood at Ningbo, China
Authors: Gu J. , Braasch H. , Burgermeister W. , Zhang J.
Published: September 2006

From January 2003 to June 2005, samples from 3416 batches of wooden packaging material were inspected for the presence of nematodes in the Ningbo Entry–Exit Inspection and Quarantine Bureau, China. Bursaphelenchus spp. were detected in 202 batches from 25 different countries. The following species were identified on the basis of their morphology and their intergenic transcribed spacer‐restriction fragment length polymorphism (ITS‐RFLP) patterns: B. xylophilus, B. fungivorus, B. rainulfi, B. hylobianum, B. thailandae, B. mucronatus, B. aberrans, B. lini, B. singaporensis, B. doui, B. conicaudatus, B. vallesianus, B. pinasteri, B. hofmanni and B. arthuri. The most frequently found species were B. mucronatus (57 batches), B. xylophilus (40 batches), B. fungivorus (21 batches), B. rainulfi (19 batches) and B. thailandae (nine batches). The pine wood nematode B. xylophilus was not only found in packaging wood imported from areas where it is known to occur (i.e. The United States of America, Japan, Korea, Hong Kong and Taiwan), but also from countries considered to be free of this dangerous pest (i.e. Brazil, Thailand, Belgium, The Netherlands, Italy and Spain). The occurrence of B. xylophilus in packaging wood from countries regarded as being free of the nematode can most likely be explained by the global circulation of wooden packaging material among infested and non‐infested countries. Our findings emphasize the need to fully implement international standards on phytosanitary treatment of packaging wood, in order to prevent further spread of the pine wood nematode, and the need for careful re‐examination of the current heat treatment measures.
Investigation of physical and bathymetric characteristics of Lakes Abaya and Chamo, Ethiopia, and their management implications
Authors: Awulachew Seleshi Bekele
Published: September 2006

The purpose of this study was to investigate the physical parameters of Lakes Abaya and Chamo in the Ethiopian rift lakes system, including such physical characteristics as depth, water resources capacity, hydrology, water balances, and impacts of water use and degradation of their watersheds. These parameters have not previously been studied for these two lakes to any significant extent. This study describes the bathymetry survey undertaken for these two lakes, and the morphometric characteristics derived from it. This study is part of a research project developed to provide further details on such parameters as hydrology, water quality, sediment inflows and deposition, lake hydrodynamics and consumptive water uses. The bathymetric survey was conducted, utilizing a combination of global positioning system (GPS) and echo sounder. To calculate the morphometric characteristics, the background lake map was digitized, and the surveyed primary data were developed as digital values. The digital values were interpolated, generating grids of the elevation surface. The elevation area and elevation volume curves (capacity curves) of the two lakes were developed from the digital values, describing the water resources capacity of the lake water basins. The results of this study increase our understanding of the water resources of these two lakes, as well as provide better understanding of their vulnerability to human activities because of their shallow depths. Immediate application of the results, as a basis for continuation of this study, also is highlighted.
A potent non‐monoaminergic paradoxical sleep inhibitory system: a reverse microdialysis and single‐unit recording study
Authors: Crochet Sylvain , Onoe Hirotaka , Sakai Kazuya
Published: September 2006

Using reverse microdialysis and polygraphic recordings in freely moving cats, we investigated the effects on sleep–waking states of application of excitatory and inhibitory amino acid agonists, cholinergic agonist and monoamines to the periaqueductal grey and adjacent mesopontine tegmentum. Single‐unit recordings during behavioural states were further used to determine the neuronal characteristics of these structures. We found that muscimol, a GABAA receptor agonist, induced a significant increase in paradoxical sleep (PS) only when applied to a dorsocaudal central tegmental field (dcFTC) located just beneath the ventrolateral periaqueductal grey. In this structure, both kainic and N‐methyl‐aspartic acids caused a dose‐dependent increase in wakefulness (W) and decrease in both slow‐wave sleep (SWS) and PS. Norepinephrine and epinephrine, and to a lesser extent histamine, also increased W and decreased SWS and PS, whereas serotonin, dopamine and carbachol, a cholinergic agonist, had no effect. Two types of neurones were recorded in this structure, those exhibiting a higher rate of tonic discharge during both W and PS compared with during SWS, and those showing a phasic increase in firing rate during both active W and PS. Both types of neurones showed a gradual increase in unit activity during PS. Our study demonstrated for the first time that the ventrolateral periaqueductal grey and dcFTC play different roles in behavioural state control, that the dcFTC neurones are critically involved in the inhibitory mechanisms of PS generation, playing a central part in its maintenance, and that these neurones are under the control of GABAergic, glutamatergic, adrenergic and histaminergic systems.
Failure of nicotine‐dependent enhancement of synaptic efficacy at Schaffer–collateral CA1 synapses of AD11 anti‐nerve growth factor transgenic mice
Authors: Sola Elisabetta , Capsoni Simona , Rosato‐Siri Marcelo , Cattaneo Antonino , Cherubini Enrico
Published: September 2006

Alzheimer's disease is a neurodegenerative disorder characterized by neuronal loss associated with a progressive impairment of cognitive functions. Early consequences of Alzheimer's disease include deficit of cholinergic signalling in particular regions controlling memory processes, such as the cortex and hippocampus, and accumulation of β‐amyloid (Aβ) peptide in neuritic plaques. The cholinergic system depends for its integrity and function on nerve growth factor. Chronic nerve growth factor deprivation in transgenic mice (AD11) engineered to produce recombinant neutralizing anti‐nerve growth factor antibodies leads to progressive age‐dependent Alzheimer's‐like neurodegenerative pathology similar to that found in patients with Alzheimer's disease, associated with a selective loss of cholinergic neurones in the basal forebrain. Here we show that in the hippocampus of 6‐month‐old AD11 mice, Aβ aggregates started appearing in the CA1 region. The accumulation of Aβ was associated with a loss of cholinergic function at CA3–CA1 synapses. Whereas in wild‐type mice nicotine induced a persistent increase of synaptic efficacy via α7 nicotine acetylcholine receptors, in AD11 mice this alkaloid failed to modify synaptic strength. Moreover, nicotine failed to transiently enhance the frequency of spontaneous miniature glutamatergic currents (miniature excitatory postsynaptic currents) recorded from CA1 but not from CA3 pyramidal neurones of AD11 mice. However, in CA3 principal cells of AD11 mice, the potentiating effect of nicotine on miniature excitatory postsynaptic currents was prevented when Aβ peptide 1–42 was added to the extracellular solution. These data suggest that in AD11 mice, Aβ interferes with nicotine acetylcholine receptors at the level of presynaptic glutamatergic terminals, inhibiting their function possibly through calcium signalling via presynaptic α7 nicotine acetylcholine receptors.
Alteration of GABAergic synapses and gephyrin clusters in the thalamic reticular nucleus of GABAA receptor α3 subunit‐null mice
Authors: Studer Remo , Von Boehmer Lotta , Haenggi Tatjana , Schweizer Claude , Benke Dietmar , Rudolph Uwe , Fritschy Jean‐Marc
Published: September 2006

Multiple GABAA‐receptor subtypes are assembled from α, β and γ subunit variants. GABAA receptors containing the α3 subunit represent a minor population with a restricted distribution in the CNS. In addition, they predominate in monoaminergic neurons and in the nucleus reticularis thalami (nRT), suggesting a role in the regulation of cortical function and sleep. Mice with a targeted deletion of the α3 subunit gene (α30/0) are viable and exhibit a subtle behavioural phenotype possibly related to dopaminergic hyperfunction. Here, we investigated immunohistochemically the consequences of the loss of α3 subunit for maturation of GABAA receptors and formation of GABAergic synapses in the nRT. Throughout postnatal development, the regional distribution of the α1, α2, or α5 subunit was unaltered in α30/0 mice and the prominent α3 subunit staining of nRT neurons in wildtype mice was not replaced. Subcellularly, as seen by double immunofluorescence, the α3 and γ2 subunit were clustered at postsynaptic sites in the nRT of adult wildtype mice along with the scaffolding protein gephyrin. In α30/0 mice, γ2 subunit clustering was disrupted and gephyrin formed large aggregates localized at the cell surface, but unrelated to postsynaptic sites, indicating that nRT neurons lack postsynaptic GABAA receptors in mutant mice. Furthermore, GABAergic terminals were enlarged and reduced in number, suggesting a partial deficit of GABAergic synapses. Therefore, GABAA receptors are required for gephyrin clustering and long‐term synapse maintenance. The absence of GABAA‐mediated transmission in the nRT may have a significant impact on the function of the thalamo‐cortical loop of α30/0 mice.
Overexpression of a truncated TrkB isoform increases the proliferation of neural progenitors
Authors: Tervonen Topi A. , Ajamian Farzam , De Wit Joris , Verhaagen Joost , Castrén Eero , Castrén Maija
Published: September 2006

The truncated isoform of TrkB, TrkB.T1, has been shown to be expressed in the neurogenic region of rodent brain. TrkB.T1 lacks tyrosine kinase activity and it may modify the action of the full‐length TrkB. We show here that the full‐length TrkB and TrkB.T1 are expressed at the same relative expression levels in mouse neural progenitor cell cultures. The number of neurosphere‐forming progenitors was reduced and apoptosis increased in neurospheres generated from mice overexpressing TrkB.T1 when compared with wild‐type neurospheres. The proliferation of the transgenic neural progenitors was increased, as indicated by the larger average diameter of spheres (140% of control), the increased cell growth in an MTT assay (137% of control) and the faster rate of 3H‐thymidine incorporation (128% of control) in the transgenic cell cultures than in controls. The proliferation of neural progenitors was also increased after lentivirus‐mediated TrkB.T1 overexpression. A significant increase in 3H‐thymidine incorporation (119% of control) and the average diameter of spheres (112% of control) in the TrkB.T1‐transduced neurospheres compared with neurospheres transduced with the control vectors confirmed the role of TrkB.T1 in proliferation of neural progenitor. When induced to differentiate, progenitors overexpressing TrkB.T1 generated two to three times more neurons than did wild‐type cells. The increase in the number of neurons correlated with an increase in the number of apoptotic cells (two‐fold) at these time points. The data indicate that changes in the relative expression levels of different TrkB isoforms influence the replicative capacity of neural progenitors.
Kindling‐induced alterations in GABAA receptor‐mediated inhibition and neurosteroid activity in the rat piriform cortex
Authors: Gavrilovici Cezar , D'Alfonso Sabrina , Dann Mathew , Poulter Michael O.
Published: September 2006

The piriform cortex makes strong interconnections with limbic structures (amygdala, entorhinal cortex and hippocampus) that are involved in memory processing. These connections have also been implicated in the development of temporal lobe epilepsy. However, little is known about how neurones in this region may change during seizure genesis. Here we tested the hypothesis that in the kindling model of temporal lobe epilepsy GABAA receptor‐mediated inhibition is altered in the piriform cortex. To do this we performed whole‐cell patch‐clamp recordings in piriform cortex brain slices obtained from non‐kindled and amygdala‐kindled adult rats. We found that kindling coincided with an increase in the amplitude and duration of miniature inhibitory post‐synaptic currents (mIPSCs) recorded from non‐pyramidal neurones, whereas the mIPSCs occurring on pyramidal (excitatory) cells did not change. Non‐stationary noise analysis of mIPSCs occurring on the non‐pyramidal neurones showed that inferred unitary conductance of synaptic channels were the same before and after kindling, implying that the channel number increased significantly. Immunocytochemical analysis of the inhibitory innervation showed that it was also unaltered by seizure induction. We also found that the effect of the positive modulator tetrahydrodeoxycorticosterone was reduced on the pyramidal neurones after kindling. In contrast, the potentiating effects of tetrahydrodeoxycorticosterone on non‐pyramidal cells were about the same after kindling as in control (sham) rats. These data indicate that amygdala kindling causes a shift in the inhibition ‘balance’ between the pyramidal and non‐pyramidal cells, perhaps leading to the disinhibition of pyramidal cells.
Hyperpolarization‐activated and cyclic nucleotide‐gated cation channel subunit 2 ion channels modulate synaptic transmission from nociceptive primary afferents containing substance P to secondary sensory neurons in laminae I–IIo of the rodent spinal dorsal horn
Authors: Papp Ildikó , Sz˝ucs Péter , Holló Krisztina , Erdélyi Ferenc , Szabó Gábor , Antal Miklós
Published: September 2006

We have previously demonstrated that hyperpolarization‐activated and cyclic nucleotide‐gated cation channel subunit 2 (HCN2) is expressed by terminals of peptidergic nociceptive primary afferents in laminae I–IIo of the rat spinal dorsal horn. In this study, we investigated the possible neurotransmitters and postsynaptic targets of these HCN2‐expressing primary afferent terminals in the superficial spinal dorsal horn by using immunocytochemical methods. We demonstrated that HCN2 widely colocalizes with substance P (SP), and that HCN2‐positive terminals that are also immunoreactive for SP form serial close appositions with dendrites and perikarya of neurokinin 1 receptor‐immunoreactive neurons. It was also found that HCN2‐immunoreactive terminals are frequently apposed to neurons that are immunoreactive for calbindin, µ‐opioid receptor and the α‐amino‐3‐hydroxy‐5‐methylisoxazole‐4‐propionate receptor subunit GluR2, markers for excitatory interneurons. Investigating HCN2 immunoreactivity in glutamic acid decarboxylase 65‐green fluorescent protein transgenic mice, we found that HCN2‐positive terminals occasionally also contact cells that contain an isoform of glutamic acid decarboxylase (glutamic acid decarboxylase 65), a marker for GABAergic inhibitory neurons. Application of ZD7288, an antagonist of HCN channels, onto neurons that were recorded in spinal cord slices with whole‐cell patch‐clamp electrodes reduced the number of monosynaptic excitatory postsynaptic potentials evoked by electrical stimulation of primary afferents at nociceptive intensities. The results suggest that HCN2 may contribute to the modulation of membrane excitability of SP‐containing nociceptive primary afferent terminals, may increase the reliability of synaptic transmission from primary afferents to secondary sensory neurons and thus may play a role in the fine‐tuning of pain transmission from nociceptive primary afferents to neurons in the spinal dorsal horn.
Is the CCK2 receptor essential for normal regulation of body weight and adiposity?
Authors: Chen Hui , Kent Stephen , Morris Margaret J.
Published: September 2006

Cholecystokinin (CCK) is a gastrointestinal satiety signal released from the duodenum to terminate feeding, via CCK1 receptors. CCK2 receptors are considered to be involved in anxiety. CCK2 receptor knockout mice have increased body weight and food intake. Little is known regarding the effects of CCK2 receptor deficiency on adipose distribution and hypothalamic feeding regulators such as neuropeptide Y (NPY), a powerful stimulator of feeding. Adult (10 week) CCK2 receptor knockout and wild‐type mice were anaesthetized and killed by decapitation. Brain sections, organs and fat tissue were dissected. Plasma leptin, insulin and brain NPY content were measured by radioimmunoassay. Female CCK2 receptor knockout mice weighed more than control mice (22.0 ± 0.2 vs. 19.9 ± 0.4 g, P < 0.05), with this difference being less marked in male mice (26.4 ± 0.4 vs. 25.6 ± 0.6 g). Fat masses in all locations sampled were significantly smaller in CCK2 receptor knockout mice of both genders (P < 0.05), resulting in lower plasma leptin and insulin levels. NPY concentrations were significantly increased in arcuate nucleus and anterior hypothalamus in both male and female CCK2 receptor knockout mice, and total hypothalamic NPY content was increased by 7 and 9% in males and females, respectively (P < 0.05). CCK2 receptor deletion was associated with increased body weight and hypothalamic NPY content, but reduced fat masses and plasma leptin and insulin. Increased NPY might contribute to increased food intake in CCK2 receptor knockout mice. Further work needs to focus on the metabolic changes.
Concurrent visuomotor behaviour improves form discrimination in a patient with visual form agnosia
Authors: Schenk Thomas , Milner A. David
Published: September 2006

It is now well established that the visual brain is divided into two visual streams, the ventral and the dorsal stream. Milner and Goodale have suggested that the ventral stream is dedicated for processing vision for perception and the dorsal stream vision for action [A.D. Milner & M.A. Goodale (1995) The Visual Brain in Action, Oxford University Press, Oxford]. However, it is possible that ongoing processes in the visuomotor stream will nevertheless have an effect on perceptual processes. This possibility was examined in the present study. We have examined the visual form‐discrimination performance of the form‐agnosic patient D.F. with and without a concurrent visuomotor task, and found that her performance was significantly improved in the former condition. This suggests that the visuomotor behaviour provides cues that enhance her ability to recognize the form of the target object. In control experiments we have ruled out proprioceptive and efferent cues, and therefore propose that D.F. can, to a significant degree, access the object's visuomotor representation in the dorsal stream. Moreover, we show that the grasping‐induced perceptual improvement disappears if the target objects only differ with respect to their shape but not their width. This suggests that shape information per se is not used for this grasping task.
Inducible and neuronal nitric oxide synthases (NOS) have complementary roles in recovery sleep induction
Authors: Kalinchuk A. V. , Stenberg D. , Rosenberg P. A. , Porkka‐Heiskanen T.
Published: September 2006

Sleep homeostasis is the process by which recovery sleep is generated by prolonged wakefulness. The molecular mechanisms underlying this important phenomenon are poorly understood. We have previously shown that nitric oxide (NO) generation increases in the basal forebrain (BF) during sleep deprivation (SD). Moreover, both NO synthase (NOS) inhibition and a NO scavenger prevented recovery sleep induction, while administration of a NO donor during the spontaneous sleep–wake cycle increased sleep, indicating that NO is necessary and sufficient for the induction of recovery sleep. Next we wanted to know which NOS isoform is involved in the production of recovery sleep. Usingin vivomicrodialysis we infused specific inhibitors of NOS into the BF of rats during SD, and found that an inhibitor of inducible NOS (iNOS), 1400W, prevented non‐rapid eye movement (NREM) recovery, while an inhibitor of neuronal NOS (nNOS), L‐N‐propyl‐arginine, decreased REM recovery but did not affect NREM recovery. Using immunoblot analysis we found that iNOS was not expressed during the spontaneous sleep–wake cycle, but was induced by prolonged wakefulness (increased by 278%). A known iNOS inducer, lipopolysaccharide, evoked an increase in sleep that closely resembled recovery sleep, and its effects were abolished by 1400W. These results suggest that the elevation of NO produced by induction of iNOS in the BF during prolonged wakefulness is a specific mechanism for producing NREM recovery sleep and that the two NOS isoforms have a complementary role in NREM and REM recovery induction.
Internalization of D2 dopamine receptors is clathrin‐dependent and select to dendro–axonic appositions in primate prefrontal cortex
Authors: Paspalas Constantinos D. , Rakic Pasko , Goldman‐Rakic Patricia S.
Published: September 2006

Much of our knowledge on trafficking of neurotransmitter receptors derives from heterologous expression systems and neurons in vitro. Understanding these dynamics in vivo for dopamine receptors, and D2 receptors (D2Rs) in particular, presents a foremost challenge as their pharmacological manipulation underlies antipsychotic medications and drug abuse, which may in turn alter response to endogenous dopamine. Here we present the first ultrastructural evidence of clathrin‐mediated endocytosis of D2Rs or any other neurotransmitter receptor in the primate brain. We have captured in situ the insertion of D2Rs in clathrin‐coated membrane pits, resulting in receptor sorting in primary endosomes. Endocytosis was specific to nonsynaptic membranes of distal dendrites, and virtually absent from larger shafts, spines, axons and perikarya expressing D2Rs. The selective association of D2Rs with the clathrin endocytotic pathway of high‐order dendrites identifies a novel substrate for monitoring and adjusting dopaminoception, as well as a potent target for dysregulation, and manipulation, of D2R signalling in mental illness.
Spatial location is accurately tracked by human auditory sensory memory: evidence from the mismatch negativity
Authors: Deouell Leon Y. , Parnes Ariel , Pickard Natasha , Knight Robert T.
Published: September 2006

The nature of spatial representation in human auditory cortex remains elusive. In particular, although humans can discriminate the locations of sounds as close as 1–10 degrees apart, such resolution has not been shown in auditory cortex of humans or animals. We used the mismatch negativity (MMN) event related brain potential to measure the neural response to spatial change in humans in narrow 10 degree spatial steps. Twelve participants were tested using a dense array EEG setup while watching a silent movie and ignoring the sounds. The MMN was reliably elicited by infrequent changes of spatial location of sounds in free field. The MMN amplitude was linearly related to the degree of spatial change with a resolution of at least 10 degrees. These electrophysiological responses occurred within a window of 100–200 milliseconds from stimulus onset, and were localized to the posterior superior temporal gyrus. We conclude that azimuthal spatial displacement is rapidly, accurately and automatically represented in auditory sensory memory in humans, at the level of the auditory cortex.
Exercise affects energy metabolism and neural plasticity‐related proteins in the hippocampus as revealed by proteomic analysis
Authors: Ding Qinxue , Vaynman Shoshanna , Souda Puneet , Whitelegge Julian P. , Gomez‐Pinilla Fernando
Published: September 2006

Studies were conducted to evaluate the effect of a brief voluntary exercise period on the expression pattern and post‐translational modification of multiple protein classes in the rat hippocampus using proteomics. An analysis of 80 protein spots of relative high abundance on two‐dimensional gels revealed that approximately 90% of the proteins identified were associated with energy metabolism and synaptic plasticity. Exercise up‐regulated proteins involved in four aspects of energy metabolism, i.e. glycolysis, ATP synthesis, ATP transduction and glutamate turnover. Specifically, we found increases in fructose‐bisphosphate aldolase C, phosphoglycerate kinase 1, mitochondrial ATP synthase, ubiquitous mitochondrial creatine kinase and glutamate dehydrogenase 1. Exercise also up‐regulated specific synaptic‐plasticity‐related proteins, the cytoskeletal protein α‐internexin and molecular chaperones (chaperonin‐containing TCP‐1, neuronal protein 22, heat shock 60‐kDa protein 1 and heat shock protein 8). Western blot was used to confirm the direction and magnitude of change in ubiquitous mitochondrial creatine kinase, an enzyme essential for transducing mitochondrial‐derived ATP to sites of high‐energy demand such as the synapse. Protein phosphorylation visualized by Pro‐Q Diamond fluorescent staining showed that neurofilament light polypeptide, glial fibrillary acidic protein, heat shock protein 8 and transcriptional activator protein pur‐alpha were more intensely phosphorylated with exercise as compared with sedentary control levels. Our results, together with the fact that most of the proteins that we found to be up‐regulated have been implicated in cognitive function, support a mechanism by which exercise uses processes of energy metabolism and synaptic plasticity to promote brain health.
Global estimates of shark catches using trade records from commercial markets
Authors: Clarke Shelley C. , McAllister Murdoch K. , Milner‐Gulland E. J. , Kirkwood G. P. , Michielsens Catherine G. J. , Agnew David J. , Pikitch Ellen K. , Nakano Hideki , Shivji Mahmood S.
Published: September 2006

Despite growing concerns about overexploitation of sharks, lack of accurate, species‐specific harvest data often hampers quantitative stock assessment. In such cases, trade studies can provide insights into exploitation unavailable from traditional monitoring. We applied Bayesian statistical methods to trade data in combination with genetic identification to estimate by species, the annual number of globally traded shark fins, the most commercially valuable product from a group of species often unrecorded in harvest statistics. Our results provide the first fishery‐independent estimate of the scale of shark catches worldwide and indicate that shark biomass in the fin trade is three to four times higher than shark catch figures reported in the only global data base. Comparison of our estimates to approximated stock assessment reference points for one of the most commonly traded species, blue shark, suggests that current trade volumes in numbers of sharks are close to or possibly exceeding the maximum sustainable yield levels.
Brooding in Corbicula madagascariensis (Bivalvia, Corbiculidae) and the repeated evolution of viviparity in corbiculids
Authors: Glaubrecht Matthias , Fehér Zoltán , Von Rintelen Thomas
Published: September 2006

The limnic bivalve genus Corbicula Megerle von Mühlfeld, 1811 is a hyper‐invasive neozoon in North and South America as well as in Europe, where currently some taxa are rapidly extending their range. In addition to its extraordinarily invasive potential, the ‘Asiatic clam’ is remarkable for its recently discovered wide spectrum of reproductive strategies comprising oviparity, ovoviviparity and euviviparity. It renders Corbicula an ideal model for studying evolutionary transformations of reproductive features, in particular with respect to intrabranchial incubation (brooding) of embryos and shelled larvae in freshwater lineages. Based on rare material from Madagascar we here present evidence for prolonged incubation interpreted as being indicative of euviviparous reproduction in C. madagascariensis Smith, 1882. This mode is not only novel for corbiculids from the Ethiopian biogeographical region, but suggests — in combination with a mtDNA phylogeny — a more complicated pattern of the evolution of reproductive modes in corbiculids than previously assumed. We find an independent origin of viviparity and even euviviparity in the South American Neocorbicula Fischer, 1887 and the Afro‐Asian Corbicula, representing a remarkable example of parallel evolution in New and Old World corbiculids.
Introduction: Organizations, Risk and Regulation
Authors: Scheytt Tobias , Soin Kim , Sahlin‐Andersson Kerstin , Power Michael
Published: September 2006

abstract Risk, regulation and practices of organizing are interrelated in a myriad of ways. Natural disasters, technical failures, and also processes of organizing are sources of risk to which organizations must respond and for which new managerial and regulatory practices are demanded. In this introduction we highlight three salient features of risk management: the (un)intended production of risk by organizations; the complex interrelationship between risk management and regulation; and the evolving and often contested nature of risk management knowledge. Each of these three themes is evident in the different contributions to this themed section.
Imbrication of Representations: Risk and Digital Technologies*
Authors: Ciborra Claudio
Published: September 2006

abstract Though emerging from different venues and backgrounds, risk management and digital applications are both based on sophisticated techniques of representation. This paper tracks the multiple overlappings and convergence between these two streams of representations. Initially digital technologies play a background role, as a tool to execute the algorithms of risk calculus. Then, they are useful in managing surveys and data analysis for those areas where risk management needs to store data on, for example, accidents. With the extension of markets for trading risk, computers and networks (or Information and Communication Technologies, ICT) become the tools of choice to allow the efficient functioning of industries like insurance. In other industries, like banking, where ‘the business’ is a vast archipelago of applications running on systems and networks, it is apparent that these integrated systems are inherently exposed to risk. Hence, these humble tools become both the infrastructure of the risk industry, and also the source of new, often incalculable risks; they move from a clear‐cut subordinate relationship (as tool) to that ofimbrication. Risk representations become more calculable and formalized, but this is obtained at the price of an incalculability of the risks of the infrastructure itself. The analysis of the multiple patterns of imbrication of representations between risk and digital technologies is applied to a range of empirical domains: from software engineering and information systems (the subservient infrastructure); to operational risk in banking; and finally to the future scenario of the democratization of finance, whereby Global Risk Information Databases (GRIDs), become gigantic machines to represent, compute, and trade all sorts of individual and social risks.[1]Overall, the paper seeks to characterize the multiple links between risk and digital technologies in organizations and draws in part on the phenomenology of representation and Heidegger's studies of Care and Concern and his later work on the essence of modern technology.
Noise Trading and the Management of Operational Risk; Firms, Traders and Irrationality in Financial Markets*
Authors: Willman Paul , Fenton‐O'Creevy Mark , Nicholson Nigel , Soane Emma
Published: September 2006

abstract  Efficient market models cannot explain the high level of trading in financial markets in terms of asset portfolio adjustment. It is presumed that much of this excessive trading is irrational ‘noise’ trading. A corollary is that there must either be irrational traders in the market or rational traders with irrational aberrations. The paper reviews the various attempts to explain noise trading in the finance literature, concluding that the persistence of irrationality is not well explained. Data from a study of 118 traders in four large investment banks are presented to advance reasons why traders might seek to trade more frequently than financial models predict. The argument is advanced that trades do not simply occur in order to generate profit, but it does not follow that such trading is irrational. Trading may generate information, accelerate learning, create commitments and enhance social capital, all of which sustain traders' long term survival in the market. The paper treats noise trading as a form of operational risk facing firms operating in financial markets and discusses approaches to the management of such risk.
Failure to Mobilize in Reliability‐Seeking Organizations: Two Cases from the UK Railway*
Authors: Busby J. S.
Published: September 2006

abstract  There is a considerable line of research on organizations dealing with large scale, intrinsic hazards. We know a good deal, as a result, about both the causation of catastrophic failure and its avoidance. Past work has explained failure in terms of (for example) structural vulnerabilities and organizational degradation – and reliability in terms of collective mindfulness, rigorous enculturation and high levels of social redundancy. This paper presents a study, based on a qualitative analysis of two disastrous collisions on the UK railway, of organizations that are strongly reliability seeking yet ultimately experience catastrophic failure. It argues that these cases implicated an organizational incapacity to mobilize systemic reform. The possibility of the two failures had been well‐known in the organizations before their occurrence, but this knowledge could not be converted into modification. A model is presented to explain how processes of systemic reform co‐exist with a set of phenomena that tend to undermine them. It is these that need to be the principal focus of efforts at managing catastrophic failure risks.
Progress in the Molecular-Genetic Study of Intelligence
Authors: Posthuma Danielle , de Geus Eco J.C.
Published: September 2006

The past decade has seen a major shift in the genetic study of human intelligence; where classic studies aimed to quantify the heritability of intelligence, current studies aim to dissect this heritability into its molecular-genetic components. Five whole-genome linkage scans have been published in the past year, converging on several chromosomal (or genomic) regions important to intelligence. A handful of candidate genes, some of which lie in these genomic regions, have shown significant association to intelligence and the associations have been replicated in independent samples. Finding genes brings us closer to an understanding of the neurophysiological basis of human cognition. Furthermore, when genes are no longer latent factors in our models but can actually be measured, it becomes feasible to identify those environmental factors that interact and correlate with genetic makeup. This will supplant the long nature–nurture debate with actual understanding.
National Character and Personality
Authors: McCrae Robert R. , Terracciano Antonio
Published: September 2006

People in all cultures have shared perceptions about the personality characteristics of the typical member of their own culture and of typical members of other cultures. Recent collaborative work has provided validated assessments of the personality profiles of over 50 cultures, and judged by these criteria, perceptions of national character are unfounded stereotypes. An appreciation of that fact by the public might improve international relations, so research is needed to understand the origins and persistence of national-character stereotypes. Psychologists have begun to explore the utility of aggregate personality profiles, which reflect subtle but real differences between cultures in mean levels of personality traits.
Representations in the Human Prefrontal Cortex
Authors: Huey Edward D. , Krueger Frank , Grafman Jordan
Published: September 2006

The prefrontal cortex (PFC) in humans has been studied for more than a century, but many crucial questions about its functions remain unanswered. This paper will highlight a few key differences between human and animal PFCs, and between the human PFC (HPFC) and other parts of the human brain. We then make a case that the HPFC is critically important for executing behaviors over time and integrating disparate information from throughout the brain. Finally, we will focus on our position in the current debate regarding how the HPFC performs its functions and discuss future directions for research.
Neighborhood Characteristics and Depression
Authors: Cutrona Carolyn E. , Wallace Gail , Wesner Kristin A.
Published: September 2006

Neighborhoods with poor-quality housing, few resources, and unsafe conditions impose stress, which can lead to depression. The stress imposed by adverse neighborhoods increases depression above and beyond the effects of the individual's own personal stressors, such as poverty and negative events within the family or workplace. Furthermore, adverse neighborhoods appear to intensify the harmful impact of personal stressors and interfere with the formation of bonds between people, again increasing risk for depression. Neighborhoods do not affect all people in the same way. People with different personality characteristics adjust in different ways to challenging neighborhoods. As a field, psychology should pay more attention to the impact of contextual factors such as neighborhoods. Neighborhood-level mental health problems should be addressed at the neighborhood level. Public housing policies that contribute to the concentration of poverty should be avoided and research should be conducted on the most effective ways to mobilize neighborhood residents to meet common goals and improve the context in which they live.
Habits—A Repeat Performance
Authors: Neal David T. , Wood Wendy , Quinn Jeffrey M.
Published: September 2006

Habits are response dispositions that are activated automatically by the context cues that co-occurred with responses during past performance. Experience-sampling diary studies indicate that much of everyday action is characterized by habitual repetition. We consider various mechanisms that could underlie the habitual control of action, and we conclude that direct cuing and motivated contexts best account for the characteristic features of habit responding—in particular, for the rigid repetition of action that can be initiated without intention and that runs to completion with minimal conscious control. We explain the utility of contemporary habit research for issues central to psychology, especially for behavior prediction, behavior change, and self-regulation.
AGGLOMERATION EXTERNALITIES, PRODUCTIVITY, AND TECHNICAL INEFFICIENCY*
Authors: Tveteras Ragnar , Battese George E.
Published: September 2006

ABSTRACT Agglomeration externalities can have positive effects on both the production possibility frontier and technical inefficiency of firms. Increased levels of localized knowledge spillovers and substitution of internal inputs with external inputs may lead to fewer errors in decision‐making and execution of production tasks, thus causing firms to become technically more efficient relative to the production frontier. When we estimate a stochastic frontier production model on a large panel of salmon aquaculture farms, we find econometric support for positive agglomeration externalities on both the production frontier and technical inefficiency.
COLLEGE‐TO‐WORK MIGRATION OF TECHNOLOGY GRADUATES AND HOLDERS OF DOCTORATES WITHIN THE UNITED STATES
Authors: Gottlieb Paul D. , Joseph George
Published: September 2006

ABSTRACT This study estimates a series of random parameter logit models of the college‐to‐work migration decisions of technology graduates and holders of doctorates within the United States. We employ detailed information on the migration‐relevant characteristics of individuals, as well as on their actual origins and destinations at the metropolitan scale. In addition to its obvious implications for “brain drain” policies in U.S. metropolitan areas, the study demonstrates the richness of the random parameters technique for behavioral‐geographic analysis. We find that science and technology graduates migrate to better educated places, other things equal; that PhD graduates pay greater attention to amenity characteristics than other degree holders; and that foreign students from some immigrant groups migrate to places where those groups are concentrated.
SPACE, TRUST, AND COMMUNAL ACTION: RESULTS FROM FIELD EXPERIMENTS IN SOUTHEAST ASIA*
Authors: Carpenter Jeffrey P. , Daniere Amrita G. , Takahashi Lois M.
Published: September 2006

ABSTRACTThis paper examines the spatial dimensions of trust in two Southeast Asian cities using data from both household surveys and field experiments conducted in low‐income communities. The results suggest that space and location are important to understanding communal action and trust in developing countries. Not surprisingly, space matters in different ways depending on culture, history and the political‐economy of a particular country or city.
GEOGRAPHIC CONCENTRATION AND ESTABLISHMENT SCALE: AN EXTENSION USING PANEL DATA*
Authors: Barrios Salvador , Bertinelli Luisito , Strobl Eric
Published: September 2006

ABSTRACT In a recent study, Holmes and Stevens (2002) identify for the first time the positive relationship that exists between establishment scale and local industry concentration using a large cross‐sectional plant‐level data set for the United States. Using an exhaustive plant‐level panel data set for Irish manufacturing covering nearly three decades, we are able to extend their analysis in two ways. First, we show that failing to control for fixed effects biases the relationship upward, although the essence of the result still remains after fixed effects are included. Second, the link is substantially weaker when plants locate for the first time in an area, but strengthens with age for those that survive in the long run. We link our results to recent contributions on the dynamics of geographic concentration.
UNDERSTANDING LOCAL CONTENT DECISIONS: ECONOMIC ANALYSIS AND AN APPLICATION TO THE AUTOMOTIVE INDUSTRY*
Authors: Veloso Francisco M.
Published: September 2006

ABSTRACTIn industrializing regions, foreign investments often generate spillovers through regional backward links. This situation may create a gap between private and social valuations of resources, resulting in a level of local content below what would be optimal for the economy. This situation creates an opportunity for the enactment of domestic content regulations. This paper presents a model to understand how these policies condition the decisions of the economic agents and affect economic welfare. Then, it simulates the model using a case study of the automotive sector. Results suggest that, in certain conditions, this local content regulation can be welfare enhancing.
Regression‐based Tests for a Change in Persistence*
Authors: Leybourne Stephen J. , Kim Tae‐Hwan , Robert Taylor A. M.
Published: September 2006

We show that the minimal forward (reverse) recursive unit tests of Banerjee, Lumsdaine and Stock [Journal of Business and Economics Statistics (1992) Vol. 10, pp. 271–288] are consistent against the alternative of a change in persistence from I(0) to I(1) [I(1) to I(0)]. However, these statistics are also shown to diverge for series which are I(0) throughout. Consequently, a rejection by these tests does not necessarily imply a change in persistence. We propose a further test, based on the ratio of these statistics, which is consistent against changes either from I(0) to I(1), or vice versa, yet does not over‐reject against constant I(0) series. Consistent breakpoint estimators are proposed.
A Logit Model with Missing Information Illustrated by Testing for Hidden Unemployment in Transition Economies
Authors: Caudill Steven B.
Published: September 2006

In an important paper,Dempster, Laird and Rubin (1977)showed how the expectation maximization (EM) algorithm could be used to obtain maximum likelihood estimates of parameters in a multinomial probability model with missing information. This article extends Dempster, Laird and Rubin's work on the EM algorithm to the estimation of a multinomial logit model with missing information on category membership. We call this new model the latent multinomial logit (LMNL) model. A constrained version of the LMNL model is used to examine the issue of hidden unemployment in transition economies following the approach ofEarle and Sakova (2000). We found an additional 0.5% hidden unemployment among workers describing themselves as self‐employed in the transition economies of Central and Eastern Europe.