bluuebunny/crossref_metadata_2025 huggingface dataset:
Selected physiologic compatibilities and incompatibilities between human and porcine organ systems
Authors: Ibrahim Zuhaib , Busch Jamie , Awwad Michel , Wagner Robert , Wells Kevin , Cooper David K. C.
Published: October 2006

Abstract:  The shortage of donor organs is a major barrier to clinical organ transplantation. Although xenotransplantation is considered one of the alternatives to human organ transplantation, there are immunologic and physiologic incompatibilities between humans and pigs. With the exception of coagulation, the major potential physiologic incompatibilities relating to function of the kidney, heart, liver, lungs, pancreatic islets, and hormones are reviewed. Some of these physiologic differences can be overcome by producing genetically altered pigs to improve compatibility with humans. The possibility of producing such pigs for organ transplantation is considered.
The annual cycle of Synechococcus (cyanobacteria) in the northern Levantine Basin shelf waters (Eastern Mediterranean)
Authors: Uysal Zahit , Köksalan İrem
Published: October 2006

Abundance of picoplanktonic chroococcoid marine cyanobacteria Synechococcus was monitored weekly over the year 1998 in shallow coastal waters of the northern Levantine Basin. The ambient physical, chemical and biological variables (temperature, salinity, Secchi disk depth, total suspended sediment, nitrate, phosphate, Chl a and phytoplankton) were also measured. Synechococcus was found to be more abundant during summer and early autumn and less during winter and early spring. At the surface and 15 m depth, cell concentrations were in the range 6.4 × 103–1.5 × 105 and 3.2 × 103–1.6 × 105 cells·ml−1, respectively. Based on the Pearson product–moment correlation analysis, a highly significant correlation between Synechococcus abundance and ambient temperature was observed (n = 40, r = 0.558, P < 0.01). As Synechococcus forms blooms that usually do not last more than a week, the short time‐scale survey achieved in this study was appropriate to reveal its abundance dynamics. Several factors such as rapid changes in nutrient concentration (especially nitrate), phytoplankton, light availability, temperature, salinity, freshwater input and vertical mixing played a relevant role on the abundance of Synechococcus over the year in the highly dynamic shallow coastal waters of the Levantine Basin.
Identification and characterization of PEBP as a calpain substrate
Authors: Chen Qinghua , Wang Susan , Thompson Stephanie N. , Hall Edward D. , Guttmann Rodney P.
Published: October 2006

Calpains are calcium‐ and thiol‐dependent proteases whose dysregulation has been implicated in a number of diseases and conditions such as cardiovascular dysfunction, ischemic stroke, and Alzheimer's disease (AD). While the effects of calpain activity are evident, the precise mechanism(s) by which dysregulated calpain activity results in cellular degeneration are less clear. In order to determine the impact of calpain activity, there is a need to identify the range of specific calpain substrates. Using an in vitro proteomics approach we confirmed that phosphatidylethanolamine‐binding protein (PEBP) as a novel in vitro and in situ calpain substrate. We also observed PEBP proteolysis in a model of brain injury in which calpain is clearly activated. In addition, with evidence of calpain dysregulation in AD, we quantitated protein levels of PEBP in postmortem brain samples from the hippocampus of AD and age‐matched controls and found that PEBP levels were approximately 20% greater in AD. Finally, with previous evidence that PEBP may act as a serine protease inhibitor, we tested PEBP as an inhibitor of the proteasome and found that PEBP inhibited the chymostrypsin‐like activity of the proteasome by ∼30%. Together these data identify PEBP as a potential in vivo calpain substrate and indicate that increased PEBP levels may contribute to impaired proteasome function.
Protective effects of an anti‐inflammatory cytokine, interleukin‐4, on motoneuron toxicity induced by activated microglia
Authors: Zhao Weihua , Xie Wenjie , Xiao Qin , Beers David R. , Appel Stanley H.
Published: October 2006

Microglia‐mediated cytotoxicity has been implicated in models of neurodegenerative diseases, such as amyotrophic lateral sclerosis, Parkinson's disease and Alzheimer's disease, but few studies have documented how neuroprotective signals might mitigate such cytotoxicity. To explore the neuroprotective mechanism of anti‐inflammatory cytokines, we applied interleukin‐4 (IL‐4) to primary microglial cultures activated by lipopolysaccharide as well as to activated microglia cocultured with primary motoneurons. lipopolysaccharide increased nitric oxide and superoxide (O2·−) and decreased insulin‐like growth factor‐1 (IGF‐1) release from microglial cultures, and induced motoneuron injury in microglia‐motoneuron cocultures. However, lipopolysaccharide had minimal effects on isolated motoneuron cultures. IL−4 interaction with microglial IL‐4 receptors suppressed and nitric oxide release, and lessened lipopolysaccharide‐induced microglia‐mediated motoneuron injury. The extent of nitric oxide suppression correlated directly with the extent of motoneuron survival. Although IL‐4 enhanced release of free IGF‐1 from microglia in the absence of lipopolysaccharide, it did not enhance free IGF‐1 release in the presence of lipopolysaccharide. These data suggest that IL‐4 may provide a significant immunomodulatory signal which can protect against microglia‐mediated neurotoxicity by suppressing the production and release of free radicals.
Hydrothermal Synthesis of Magnesium Aluminate Platelets
Authors: Chen Zhi‐Zhan , Shi Er‐Wei , Zhang Hua‐Wei , Zhang Yong , Li Xiang‐Biao , Liu Xue‐Chao , Xiao Bing
Published: October 2006

Magnesium aluminate (MgAl2O4) platelets were first synthesized by hydrothermal treatment of γ‐AlO(OH) in a magnesium nitrate aqueous solution at 400°C. The platelets are 100–200 nm in width and 25 nm in thickness. The influence of temperature, the anions of the magnesium salt, the amount of magnesium salt, and precursor pH on the formation of such structure was investigated. The experimental results indicated that the anions of the magnesium salt and precursor pH could have a significant influence on the growth of MgAl2O4. MgAl2O4 formation followed the in situ transformation mechanism, which was the reason why the MgAl2O4 crystallites had a platelet morphology.
Antisense‐Mediated Depletion of Tomato Chloroplast Omega‐3 Fatty Acid Desaturase Enhances Thermal Tolerance
Authors: Liu Xun‐Yan , Yang Jing‐Hua , Li Bin , Yang Xiu‐Mei , Meng Qing‐Wei
Published: October 2006

A chloroplast‐localized tomato (Lycopersicon esculentum Mill.) ω‐3 fatty acid desaturase gene (LeFAD7) was isolated and characterized with regard to its sequence, response to various temperatures, and function in antisense transgenic tomato plants. The deduced amino acid sequence had four histidine‐rich regions, of which three regions were highly conserved throughout the whole ω‐3 fatty acid desaturase gene family. Southern blotting analysis showed that LeFAD7 was encoded by a single copy gene and had two homologous genes in the tomato genome. Northern blot showed that LeFAD7 was expressed in all organs and was especially abundant in leaf tissue. Meanwhile, expression of LeFAD7 was induced by chilling stress (4 °C), but was inhibited by high temperature (45 °C), in leaves. Transgenic tomato plants were produced by integration of the antisense LeFAD7 DNA under the control of a CaMV35S promoter into the genome. Antisense transgenic plants with lower 18:3 content could maintain a higher maximal photochemical efficiency (Fv/Fm) and O2 evolution rate than wild‐type plants. These results suggested that silence of the LeFAD7 gene alleviated high‐temperature stress. There was also a correlation between the low content of 18:3 resulting from silence of the LeFAD7 gene and tolerance to high‐temperature stress.

(Managing editor: Li‐Hui Zhao)
Low mtDNA diversity among widespread Australian diamondback moth Plutella xylostella (L.) suggests isolation and a founder effect
Authors: SAW JESSLYN , ENDERSBY NANCY M. , MCKECHNIE STEPHEN W.
Published: October 2006

Abstract
Populations of Australian diamondback moth (DBM) Plutella xylostella (L.), a serious pest of cruciferous crops, display extremely low levels of genetic differentiation across Australia and New Zealand sample locations, as determined previously using microsatellite markers. These data suggest high levels of contemporary gene flow that is consistent with Australian DBM being a vagile species. Here we examine Australian DBM samples for haplotype variation using the mitochondrial DNA sequences of a 257 bp fragment of the CO1 gene. We compare this variation to equivalent mtDNA sequence variation in samples from New Zealand, Kenya and Korea. Using 42 moths collected throughout Australia we show that Australian DBM have both low mtDNA haplotype and nucleotide diversities. The three Australian haplotypes detected are closely related and they cluster with the common haplotype group from Indonesia. In addition the Australian haplotype frequency distribution resembled more that from Indonesia than that from Kenya or Korea. These data are consistent with an original strong Australian/New Zealand founder effect, from a south‐eastern Asian source, with subsequent continued isolation. In a single season, the frequency of PXMt01, the most common Australian haplotype, was estimated at 15 locations spread across southern Australia and New Zealand using a polymerase chain reaction BiPASA method. The PXMt01 haplotype frequency variation was heterogenous, suggesting a small degree of population isolation that was not detected using microsatellites. Differentiation was not a function of geographical distance. These data suggest transient and sporadic local colonisation events by small numbers of founding females.
Spatial distribution of banana skipper (Erionota thrax L.) (Lepidoptera: Hesperiidae) and its parasitoids in a Cavendish banana plantation, Penang, Malaysia
Authors: OKOLLE JUSTIN N. , MANSOR MASHHOR , AHMAD ABU HASSAN
Published: October 2006

Abstract
Spatial distribution of immatures of the banana skipper (Erionota thrax L.) and their parasitisms from three major parasitoids were studied in a Cavendish banana plantation from April 2004 to December 2004. Infestation levels and parasitism of E. thrax life stages were recorded from bunched plants (BP), flowering plants (FP), preflowered plants (PF), broad leaf followers (BLF) and narrow leaf followers (NLF), as well as on well managed and poorly managed plants. Mean numbers of the immatures and numbers parasitized from the nine blocks in the plantation were fitted to four dispersion indices. Significant numbers of E. thrax immatures and those parasitized by Ooencyrtus erionotae, Cotesia erionotae and Brachymeria albotibialis were recorded from BLF and PF; no eggs were found on BP and FP. Although infestation was higher on well managed plants, only larval parasitism was significantly different. Three of the four indices indicated that eggs and larvae were random while all the indices showed pupae to be clumped. Parasitized eggs and pupae were clumped (4/4 indices) while 3/4 indices revealed a random pattern for parasitized larvae.
Philosophy of Action and Philosophy of Religion
Authors: Goetz Stewart
Published: October 2006

The world's major monotheistic religions typically maintain that God freely chose, in the libertarian sense, to create the universe for a reason or purpose. Philosophers of religion often argue that the idea that God makes a free choice to create for a purpose is deeply flawed. In parallel with these philosophers of religion, philosophers of action typically argue that the idea that human beings make free choices to act for purposes is also flawed. I begin my article by briefly summarizing what is involved in the idea of a human agent freely choosing for a purpose. I then examine criticisms of this idea by philosophers of action and suggest how they might plausibly be rebutted. I conclude by suggesting that if these criticisms by philosophers of action are suspect, then there is good reason for thinking that the same or similar criticisms by philosophers of religion are suspect.
Psychiatric injury in breach of a relationship
Authors: Handford Peter
Published: October 2006

The distinction between primary and secondary victims confirmed by Page v Smith has caused major problems in English psychiatric damage law. The House of Lords has suggested that the search for principle has been called off, and that the only sensible strategy is to say ‘thus far and no farther’. This paper suggests that one way forward is to recognise that it is not only persons who are physically proximate to an ‘accident’ who should be put in a special category: any case in which there is some sort of pre-existing relationship between claimant and defendant should be regarded as different from the standard secondary victim scenario. The relationship concept, first recognised in the USA and now adopted by the Court of Appeal, can be found in embryo form in the early cases.
Montelukast in allergic rhinitis: a systematic review and meta‐analysis
Authors: Grainger J. , Drake‐Lee A.
Published: October 2006

Key points

• Allergic rhinitis is common.

• This systematic review outlines the evidence regarding montelukast in allergic rhinitis and provides a meta‐analysis of its efficacy.

• The evidence suggests that montelukast does reduce nasal symptom score by 3.4% (95% CI: 2.5% to 4.2%) when compared with placebo.

• Montelukast is not as effective as topical nasal steroids or antihistamines and should therefore be regarded as second line therapy.

• When used, montelukast should be used in combination with an antihistamine.
Defining the stenotic post‐laryngectomy tracheostoma and its impact on the quality of life in laryngectomees: development and validation of a stoma function questionnaire
Authors: Paleri V. , Wight R.G. , Owen S. , Hurren A. , Stafford F.W.
Published: October 2006

Objectives:  The aims of this study were to identify if: (i) size of stoma contributes to quality of life (QoL) in laryngectomees; (ii) stoma size has an impact on routine stoma care and function; and (iii) an optimal stoma size exists below which patients experience stoma problems.

Design:  Cross‐sectional study of laryngectomees.

Setting:  Two tertiary care centres.

Participants:  Fifty‐seven patients who had undergone total laryngectomy one to five years ago and using tracheo‐oesophageal speech as their primary communication means.

Main outcomes measures:  Three main measures were studied:

1 a new study specific questionnaire designed to assess problems with function and care of the end tracheosto‐ ma;

2 QoL as assessed by the head and neck QoL instrument;

3 a precision custom designed sizer to measure the minimum stoma diameter.

Results:  The final study‐specific questionnaire contained four items assessing different aspects of stomal function. From raw total scores an overall stomal score was generated. The stoma score was moderately correlated to emotion and speech domains in head and neck Quality of Life questionnaire, indicating that different concepts were being measured. The mean minimum stoma diameter was 15.9 ± 2.9 mm. There was a significant increase in the area under the receiver operating characteristic curve beyond a threshold value of ≥15 mm; smaller sizes were associated with a poorer stoma score (Mann–Whitney test, P < 0.001). No patient found the stoma sizer use distressing.

Conclusions:  Size of stoma significantly contributes to QoL in laryngectomees and stomas with minimum diameters of 14 mm or less are associated with adverse effects on routine stoma function. The study‐specific stoma function questionnaire appears to be a useful instrument.
A comparison of endoscopic and microscopic removal of wax: a randomised clinical trial
Authors: Pothier D. D. , Hall C. , Gillett S.
Published: October 2006

Objectives:  Using a microscope to achieve a view of the canal during dewaxing is the most commonly performed method of dewaxing in secondary care, but an endoscope can also be used. We set out to compare endoscopic and microscopic dewaxing.

Design:  Randomised clinical trial.

Setting:  Otolaryngology Outpatient Department.

Participants:  One hundred participants selected sequentially from patients requiring dewaxing of their ears to allow examination of the tympanic membrane. Patients with external or middle ear pathology were excluded.

Methods:  Patients were randomly assigned to have dewaxing performed using microinstruments aided by vision with a microscope or an endoscope. All participants who were entered the study completed the study.

Main outcome measures:  Levels of pain and discomfort experienced by the participants were assessed by a visual analogue scale (VAS). Difficulty of performing the dewaxing indicated by the endoscopist using a VAS. The length of time taken to perform the dewaxing was also recorded.

Results:  Endoscopic dewaxing was less uncomfortable than microscopic dewaxing for patients (VAS median values 5 and 25 respectively; P < 0.002) as well as less painful (VAS median values 3.5 and 10 respectively; P < 0.075). Endoscopic dewaxing was easier to perform than microscopic dewaxing (VAS median values for difficulty were 9 and 20 respectively; P < 0.005) and took less time (mean time for endoscopic dewaxing was 1.8 min versus 3.3 min for microscopic dewaxing (P < 0.001). Ninety‐one per cent of ears could be dewaxed with a Jobson–Horne probe or wax hook.

Conclusions:  The cost of an operating microscope suitable for use with dewaxing is approximately 10 times that of a suitable endoscope, dewaxing is a cheaper alternative to microscopic dewaxing that has benefits for the patient and clinician.
Differential Regulation of the Three Methanol Methyltransferase Isozymes in
Methanosarcina acetivorans
C2A
Authors: Bose Arpita , Pritchett Matthew A. , Rother Michael , Metcalf William W.
Published: October 2006

Genetic analysis of the three methanol-specific methyltransferase 1 operons (
mtaCB1
,
mtaCB2
, and
mtaCB3
) in
Methanosarcina acetivorans
led to the suggestion that each of them has a discrete function during growth on methanol, which might be reflected in differential gene regulation (Pritchett and Metcalf, Mol. Microbiol.
56:
1183-1194, 2005). To test this suggestion, reporter gene fusions were constructed for each of the three operons, and their expression was examined under various growth conditions. Expression of the
mtaCB1
and
mtaCB2
fusions was 100-fold and 575-fold higher, respectively, in methanol-grown cells than in trimethylamine (TMA)-grown cells. The
mtaCB3
fusion was expressed at low levels on methanol, TMA, and dimethylamine but was significantly upregulated on monomethylamine and acetate. When TMA- or acetate-grown cultures were shifted to methanol, the
mtaCB1
fusion was expressed most highly during exponential phase, whereas the
mtaCB2
fusion, although strongly induced prior to
mtaCB1
expression, did not reach full expression levels until stationary phase. The
mtaCB3
fusion was transiently expressed prior to entry into exponential phase during a TMA-to-methanol substrate shift experiment. When acetate-grown cells were shifted to medium containing both TMA and methanol, TMA utilization commenced prior to utilization of methanol; however, these two substrates were consumed simultaneously later in growth. Under these conditions expression of the
mtaCB2
and
mtaCB3
fusions was delayed, suggesting that methylamines may repress their expression.
Phototaxis and Impaired Motility in Adenylyl Cyclase and Cyclase Receptor Protein Mutants ofSynechocystissp. Strain PCC 6803
Authors: Bhaya Devaki , Nakasugi Kenlee , Fazeli Fariba , Burriesci Matthew S.
Published: October 2006

We have carefully characterized and reexamined the motility and phototactic responses ofSynechocystissp. adenylyl cyclase (Cya1) and catabolite activator protein (SYCRP1) mutants to different light regimens, glucose, 3-(3,4-dichlorophenyl)-1,1-dimethylurea, and cyclic AMP. We find that contrary to earlier reports,cya1andsycrp1mutants are motile and phototactic but are impaired in one particular phase of phototaxis in comparison with wild-typeSynechocystissp.
AmiC Functions as an
N
-Acetylmuramyl-
l
-Alanine Amidase Necessaryfor Cell Separation and Can Promote Autolysis in
Neisseria gonorrhoeae
Authors: Garcia Daniel L. , Dillard Joseph P.
Published: October 2006

Neisseria gonorrhoeae
is prone to undergo autolysis under many conditions
not conducive to growth. The role of autolysis during gonococcal
infection is not known, but possible advantages for the bacterial
population include provision of nutrients to a starving population,
modulation of the host immune response by released cell components, and
donation of DNA for natural transformation. Biochemical studies
indicated that an
N
-acetylmuramyl-
l
-alanine amidase
is responsible for cell wall breakdown during autolysis. In order to
better understand autolysis and in hopes of creating a nonautolytic
mutant, we mutated
amiC
, the gene for a putative
peptidoglycan-degrading amidase in
N. gonorrhoeae
.
Characterization of peptidoglycan fragments released during growth
showed that an
amiC
mutant did not produce free disaccharide,
consistent with a role for AmiC as an
N
-acetylmuramyl-
l
-alanine amidase. Compared to the
wild-type parent, the mutant exhibited altered growth characteristics,
including slowed exponential-phase growth, increased turbidity in
stationary phase, and increased colony opacity. Thin-section electron
micrographs showed that mutant cells did not fully separate but grew as
clumps. Complementation of the
amiC
deletion mutant with
wild-type
amiC
restored wild-type growth characteristics and
transparent colony morphology. Overexpression of
amiC
resulted
in increased cell lysis, supporting AmiC's purported function as a
gonococcal autolysin. However,
amiC
mutants still underwent
autolysis in stationary phase, indicating that other gonococcal enzymes
are also involved in this
process.
Blocking Chromosome Translocation during Sporulation ofBacillus subtilisCan Result in Prespore-Specific Activation of σGThat Is Independent of σEand of Engulfment
Authors: Chary Vasant K. , Xenopoulos Panagiotis , Piggot Patrick J.
Published: October 2006

Formation of spores byBacillus subtilisis characterized by cell compartment-specific gene expression directed by four RNA polymerase σ factors, which are activated in the order σF-σE-σG-σK. Of these, σGbecomes active in the prespore upon completion of engulfment of the prespore by the mother cell. Transcription of the gene encoding σG,spoIIIG, is directed in the prespore by RNA polymerase containing σFbut also requires the activity of σEin the mother cell. When first formed, σGis not active. Its activation requires expression of additional σE-directed genes, including the genes required for completion of engulfment. Here we report conditions in which σGbecomes active in the prespore in the absence of σEactivity and of completion of engulfment. The conditions are (i) having anspoIIIEmutation, so that only the origin-proximal 30% of the chromosome is translocated into the prespore, and (ii) placingspoIIIGin an origin-proximal location on the chromosome. The main function of the σE-directed regulation appears to be to coordinate σGactivation with the completion of engulfment, not to control the level of σGactivity. It seems plausible that the role of σEin σGactivation is to reverse some inhibitory signal (or signals) in the engulfed prespore, a signal that is not present in thespoIIIEmutant background. It is not clear what the direct activator of σGin the prespore is. Competition for core RNA polymerase between σFand σGis unlikely to be of major importance.
Cn-MOVE AND ITS DUPLICATED MOVE OF LINKS
Authors: KOBAYASHI KAZUAKI , SHIBUYA TETSUO , YASUHARA AKIRA
Published: October 2006

A local move is a pair of tangles with same end points. Habiro defined a system of local moves, Cn-moves, and showed that two knots have the same Vassiliev invariants of order ≤ n - 1 if and only if they are transformed into each other by Cn-moves. We define a local move, βn-move, which is obtained from a Cn-move by duplicating a single pair of arcs with same end points. Then we immediately have that a Cn+1-move is realized by a βn-move and that a βn-move is realized by twice Cn-moves. In this note we study the relation between Cn-move and βn-move, and in particular, give answers to the following questions: (1) Is a βn-move realized by a finite sequence of Cn+1-moves? (2) Is Cn-move realized by a finite sequence of βn-moves?
ON EXTREME COEFFICIENTS OF THE JONES–KAUFFMAN POLYNOMIAL FOR VIRTUAL LINKS
Authors: AVDEEV ROMAN S.
Published: October 2006

An important problem of knot theory is to find or estimate the extreme coefficients of the Jones–Kauffman polynomial for (virtual) links with a given number of classical crossings. This problem has been studied by Morton and Bae [1] and Manchón [11] for the case of classical links. It turns out that the general case can be reduced to the case when the extreme coefficient function is expressible in terms of chord diagrams (previous authors consider only d-diagrams which correspond to the classical case [9]). We find the maximal absolute values for generic chord diagrams, thus, for generic virtual knots. Also we consider the "next" coefficient of the Jones–Kauffman polynomial in terms of framed chord diagrams and find its maximal value for a given number of chords. These two functions on chord diagrams are of their own interest because there are related to the Vassiliev invariants of classical knots and J-invariants of planar curves, as mentioned in [10].
GLOBAL PROPERTIES OF SPACELIKE CURVES IN MINKOWSKI 3-SPACE
Authors: IZUMIYA SHYUICHI , KIKUCHI MAKOTO , TAKAHASHI MASATOMO
Published: October 2006

We study global properties of closed spacelike curves in Minkowski 3-space.
ON DEFAULT CORRELATION AND PRICING OF COLLATERALIZED DEBT OBLIGATION BY COPULA FUNCTIONS
Authors: LI PING , CHEN HOUSHENG , DENG XIAOTIE , ZHANG SHUNMING
Published: October 2006

Default correlation is the key point for the pricing of multi-name credit derivatives. In this paper, we apply copulas to characterize the dependence structure of defaults, determine the joint default distribution, and give the price for a specific kind of multi-name credit derivative — collateralized debt obligation (CDO). We also analyze two important factors influencing the pricing of multi-name credit derivatives, recovery rates and copula function. Finally, we apply Clayton copula, in a numerical example, to simulate default times taking specific underlying recovery rates and average recovery rates, then price the tranches of a given CDO and then analyze the results.
MODEL RISK IN VaR ESTIMATION: AN EMPIRICAL STUDY
Authors: YAO JING , LI ZHONG-FEI , NG KAI W.
Published: October 2006

This paper studies the model risk; the risk of selecting a model for estimating the Value-at-Risk (VaR). By considering four GARCH-type volatility processes exponentially weighted moving average (EWMA), generalized autoregressive conditional heteroskedasticity (GARCH), exponential GARCH (EGARCH), and fractionally integrated GARCH (FIGARCH), we evaluate the performance of the estimated VaRs using statistical tests including the Kupiec's likelihood ratio (LR) test, the Christoffersen's LR test, the CHI (Christoffersen, Hahn, and Inoue) specification test, and the CHI nonnested test. The empirical study based on Shanghai Stock Exchange A Share Index indicates that both EGARCH and FIGARCH models perform much better than the other two in VaR computation and that the two CHI tests are more suitable for analyzing model risk.
GAME THEORETICAL ANALYSIS OF BUY-IT-NOW PRICE AUCTIONS
Authors: YU HAI , DANG CHUANGYIN , WANG SHOU-YANG
Published: October 2006

We study two kinds of buy-it-now options, temporary and permanent, under a theoretical model of Stackelberg game. In this two-stage game, the bidders, as the followers, use a two-threshold strategy to determine whether to bid or directly buy the item at the posted price, given an auction configuration featured by the seller in the first stage and other common knowledge. Under the uniform distribution assumption for the bidders' valuation, we derive the optimal necessary conditions of the starting price and the buy-it-now price for maximizing the seller's expected revenue. Then, we use two numerical experiments to find some interesting insights, which include that under identical bidders' participation costs, the temporary buy-it-now option can acquire a higher expected revenue for the seller than the permanent option, and a buy-it-now price auction always nontrivially dominates a regular auction in terms of the achieved expected revenue, no matter whether the seller or the bidders are risk-averse.
Cross-talk between Language Processes and Overt Motor Behavior in the First 200 msec of Processing
Authors: Boulenger Véronique , Roy Alice C. , Paulignan Yves , Deprez Viviane , Jeannerod Marc , Nazir Tatjana A.
Published: October 2006

A recently emerging view sees language understanding as closely linked to sensory and motor processes. The present study investigates this issue by examining the influence of processing action verbs and concrete nouns on the execution of a reaching movement. Fine-grained analyses of movement kinematics revealed that relative to nouns, processing action verbs significantly affects overt motor performance. Within 200 msec after onset, processing action verbs interferes with a concurrent reaching movement. By contrast, the same words assist reaching movement when processed before movement onset. The cross-talk between language processes and overt motor behavior provides unambiguous evidence that action words and motor action share common cortical representations and could thus suggest that cortical motor regions are indeed involved in action word retrieval.
A Moment to Reflect upon Perceptual Synchrony
Authors: Elliott Mark A. , Shi Zhuanghua , Kelly Sean D.
Published: October 2006

How does neuronal activity bring about the interpretation of visual space in terms of objects or complex perceptual events? If they group, simple visual features can bring about the integration of spikes from neurons responding to different features to within a few milliseconds. Considered as a potential solution to the “binding problem,” it is suggested that neuronal synchronization is the glue for binding together different features of the same object. This idea receives some support from correlated- and periodic-stimulus motion paradigms, both of which suggest that the segregation of a figure from ground is a direct result of the temporal correlation of visual signals. One could say that perception of a highly correlated visual structure permits space to be bound in time. However, on closer analysis, the concept of perceptual synchrony is insufficient to explain the conditions under which events will be seen as simultaneous. Instead, the grouping effects ascribed to perceptual synchrony are better explained in terms of the intervals of time over which stimulus events integrate and seem to occur simultaneously. This point is supported by the equivalence of some of these measures with well-established estimates of the perceptual moment. However, it is time in extension and not the instantaneous that may best describe how seemingly simultaneous features group. This means that studies of perceptual synchrony are insufficient to address the binding problem.
Magnetic Stimulation of the Left Visual Cortex Impairs Expert Word Recognition
Authors: Skarratt Paul A. , Lavidor Michal
Published: October 2006

One of the hallmarks of expert reading is the ability to identify arrays of several letters quickly and in parallel. Such length-independent reading has only been found for word stimuli appearing in the right visual hemifield (RVF). With left hemifield presentation (LVF), response times increase as a function of word length. Here we investigated the comparative efficiency with which the two hemispheres are able to recognize visually presented words, as measured by word length effects. Repetitive transcranial magnetic stimulation (rTMS) of the left occipital cortex disrupted expert processing of the RVF such that a length effect was created (Experiment 1). Right occipital rTMS, on the other hand, had no such effect on RVF words and nor did it modulate the length effect already present in the LVF. Experiment 2 explored the time course of these TMS-induced effects by applying single pulses of TMS at various stimulus-onset asynchronies for the same task. We replicated the TMS-induced length effect for RVF words, but only when a single pulse was applied to the left visual cortex 80 msec after target presentation. This is the first demonstration of TMS-induced impairment producing a word length effect, and as such confirms the specialization of the left hemisphere in word recognition. It is likely that anatomical differences in the pathway linking retinal input to higher level cortical processing drive this effect.
Mental Representation of Verb Meaning: Behavioral and Electrophysiological Evidence
Authors: Li Xuesong , Shu Hua , Liu Youyi , Li Ping
Published: October 2006

Previous psycholinguistic research has debated the nature of the mental representation of verbs and the access of relevant verb information in sentence processing. In this study, we used behavioral and electrophysiological methods to examine the representation of verbs in and out of sentence contexts. In five experiments, word naming and event-related potential (ERP) components were used to measure the speed and the amplitude, respectively, associated with different verb-object combinations that result in different degrees of fit between the verb and its object. Both naming speed and ERP amplitudes (N400) are proven to be sensitive indices of the degree of fit, varying as a function of how well the object fits the verb in terms of selectional restrictions. The results suggest that the semantic features of the verb's arguments are an integral part of the mental representation of verbs, and such information of the verb is accessed and used on-line during sentence processing. Implications of these results are discussed in light of recent computational semantic models that view the lexicon through high-order lexical co-occurrences in language use.
Training for Chairing: A Practical Approach
Authors: Hemery John , Meerts Paul
Published: October 2006

This article draws on the experience of two series of courses in negotiation and chairing, fifty in all, conducted in preparation for the UK and Finnish Presidencies of the European Union, 2005 and 2006. It outlines the concept and design of the programme, and introduces a four-part analysis of the chair's role which provided the intellectual framework for the series. It examines in detail the structure of the courses and the practical exercises which formed the core of the training. A concluding section draws together the lessons learned. The article would be helpful specifically to those preparing officials for the Presidency of the EU, but also for multilateral negotiations more generally, as well as to those interested in the theory and practice of chairing.
Can CGCMs Simulate the Twentieth-Century “Warming Hole” in the Central United States?
Authors: Kunkel Kenneth E. , Liang Xin-Zhong , Zhu Jinhong , Lin Yiruo
Published: October 2006

The observed lack of twentieth-century warming in the central United States (CUS), denoted here as the “warming hole,” was examined in 55 simulations driven by external historical forcings and in 19 preindustrial control (unforced) simulations from 18 coupled general circulation models (CGCMs). Twentieth-century CUS trends were positive for the great majority of simulations, but were negative, as observed, for seven simulations. Only a few simulations exhibited the observed rapid rate of warming (cooling) during 1901–40 (1940–79). Those models with multiple runs (identical forcing but different initial conditions) showed considerable intramodel variability with trends varying by up to 1.8°C century−1, suggesting that internal dynamic variability played a major role at the regional scale. The wide range of trend outcomes, particularly for those models with multiple runs, and the small number of simulations similar to observations in both the forced and unforced experiments suggest that the warming hole is not a robust response of contemporary CGCMs to the estimated external forcings. A more likely explanation based on these models is that the observed warming hole involves external forcings combined with internal dynamic variability that is much larger than typically simulated.

The observed CUS temperature variations are positively correlated with North Atlantic (NA) sea surface temperatures (SSTs), and both NA SSTs and CUS temperature are negatively correlated with central equatorial Pacific (CEP) SSTs. Most models simulate rather well the connection between CUS temperature and NA SSTs. However, the teleconnections between NA and CEP SSTS and between CEP SSTs and CUS temperature are poorly simulated and the models produce substantially less NA SST variability than observed, perhaps hampering their ability to reproduce the warming hole.
Defining Intraseasonal Rainfall Variability within the North American Monsoon
Authors: Englehart Phil J. , Douglas Arthur V.
Published: October 2006

This study provides an empirical description of intraseasonal rainfall variability within the North American monsoon (NAM) region. Applying particular definitions to historical daily rainfall observations, it demonstrates that distinct intraseasonal rainfall modes exist and that these modes differ considerably from the monsoon core region in northwest Sonora (SON), California, to its northward extension in southeast Arizona (AZ). To characterize intraseasonal rainfall variability (ISV), separate P-mode principal component (PC) analyses were performed for SON and AZ. The results indicate that in each area, much of the ISV in rainfall can be described by three orthogonal modes. The correlations between ISV modes and total seasonal rainfall reinforce the notion of differing behaviors between the monsoon’s core and extension. For SON all three ISV modes exhibit significant correlation with seasonal rainfall, with the strongest relationship in evidence for the ISV mode, which is related to rainfall intensity. For AZ, total rainfall exhibits the strongest correlation with the ISV mode, which emphasizes season length and rainfall consistency. Examination of longer-period behavior in the ISV modes indicates that, for SON, there is a positive linear trend in intensity, but a countervailing trend toward a shorter monsoon season along with less consistent rainfall in the form of shorter wet spells. For AZ, the evidence for trend in the ISV modes is not nearly as compelling, though one of the modes appears to exhibit distinct multidecadal variability. This study also evaluates teleconnectivity between ENSO, the Pacific decadal oscillation (PDO), and the NAM’s intraseasonal rainfall variability. Results indicate that part of the intraseasonal rainfall variability in both SON and AZ is connected to ENSO while only SON exhibits a teleconnection with the long-period fluctuations of the PDO.
Comparison of Precipitation from Observed Data and General Circulation Models over the Iberian Peninsula
Authors: Nieto Susana , Rodríguez-Puebla Concepción
Published: October 2006

In this paper, the ability of model outputs from the Intergovernmental Panel on Climate Change (IPCC) to describe the natural internal variability of precipitation observations is evaluated. The analysis is focused on the Iberian Peninsula for December–February (DJF). The study was performed with observed data from National Meteorological Institutes, reanalysis data from the National Centers for Environmental Prediction–National Center for Atmospheric Research, teleconnection indices, and model simulations. First, the seasonal cycle, mean winter pattern, and tendency for nine model simulations were evaluated. Then, four models were selected to obtain interannual variability and to diagnose the links between precipitation and large-scale circulation. This intercomparison is based on the modes obtained by the empirical orthogonal function (EOF) and spectral analyses to investigate the temporal properties of the most significant spatial patterns. The models well reproduce the observed seasonal cycle and the mean winter pattern; however, they poorly capture the interannual variability found in observed data. To ascertain the reasons for these results, features affecting the precipitation process are considered by analyzing the relationships with the dominant modes of large-scale atmospheric fields, such as sea level pressure, storm activity, jet stream, moisture flux, and teleconnection indices. The precipitation response to the mean flow suggests signs of potential seasonal predictability in DJF.
The Effect of a Large Freshwater Perturbation on the Glacial North Atlantic Ocean Using a Coupled General Circulation Model
Authors: Hewitt C. D. , Broccoli A. J. , Crucifix M. , Gregory J. M. , Mitchell J. F. B. , Stouffer R. J.
Published: October 2006

The commonly held view of the conditions in the North Atlantic at the last glacial maximum, based on the interpretation of proxy records, is of large-scale cooling compared to today, limited deep convection, and extensive sea ice, all associated with a southward displaced and weakened overturning thermohaline circulation (THC) in the North Atlantic. Not all studies support that view; in particular, the “strength of the overturning circulation” is contentious and is a quantity that is difficult to determine even for the present day. Quasi-equilibrium simulations with coupled climate models forced by glacial boundary conditions have produced differing results, as have inferences made from proxy records. Most studies suggest the weaker circulation, some suggest little or no change, and a few suggest a stronger circulation.

Here results are presented from a three-dimensional climate model, the Hadley Centre Coupled Model version 3 (HadCM3), of the coupled atmosphere–ocean–sea ice system suggesting, in a qualitative sense, that these diverging views could all have occurred at different times during the last glacial period, with different modes existing at different times. One mode might have been characterized by an active THC associated with moderate temperatures in the North Atlantic and a modest expanse of sea ice. The other mode, perhaps forced by large inputs of meltwater from the continental ice sheets into the northern North Atlantic, might have been characterized by a sluggish THC associated with very cold conditions around the North Atlantic and a large areal cover of sea ice. The authors’ model simulation of such a mode, forced by a large input of freshwater, bears several of the characteristics of the Climate: Long-range Investigation, Mapping, and Prediction (CLIMAP) Project’s reconstruction of glacial sea surface temperature and sea ice extent.
Rescuer Fatigue: Standard versus Continuous Chest‐Compression Cardiopulmonary Resuscitation
Authors: Heidenreich Joseph W. , Berg Robert A. , Higdon Travis A. , Ewy Gordon A. , Kern Karl B. , Sanders Arthur B.
Published: October 2006

Objectives Continuous chest‐compression cardiopulmonary resuscitation (CCC‐CPR) has been advocated as an alternative to standard CPR (STD‐CPR). Studies have shown that CCC‐CPR delivers substantially more chest compressions per minute and is easier to remember and perform than STD‐CPR. One concern regarding CCC‐CPR is that the rescuer may fatigue and be unable to maintain adequate compression rate or depth throughout an average emergency medical services response time. The specific aim of this study was to compare the effects of fatigue on the performance of CCC‐CPR and STD‐CPR on a manikin model.

Methods This was a prospective, randomized crossover study involving 53 medical students performing CCC‐CPR and STD‐CPR on a manikin model. Students were randomized to their initial CPR group and then performed the other type of CPR after a period of at least two days. Students were evaluated on their performance of 9 minutes of CPR for each method. The primary endpoint was the number of adequate chest compressions (at least 38 mm of compression depth) delivered per minute during each of the 9 minutes. The secondary endpoints were total compressions, compression rate, and the number of breaks taken for rest. The students' performance was evaluated on the basis of Skillreporter Resusci Anne (Laerdal, Wappingers Falls, NY) recordings. Primary and secondary endpoints were analyzed by using the generalized linear mixed model for counting data.

Results In the first 2 minutes, participants delivered significantly more adequate compressions per minute with CCC‐CPR than STD‐CPR, (47 vs. 32, p = 0.004 in the 1st minute and 39 vs. 29, p = 0.04 in the 2nd minute). For minutes 3 through 9, the differences in number of adequate compressions between groups were not significant. Evaluating the 9 minutes of CPR as a whole, there were significantly more adequate compressions in CCC‐CPR vs. STD‐CPR (p = 0.0003). Although the number of adequate compressions per minute declined over time in both groups, the rate of decline was significantly greater in CCC‐CPR compared with STD‐CPR (p = 0.0003). The mean number of total compressions delivered in the first minute was significantly greater with CCC‐CPR than STD‐CPR (105 per minute vs. 58 per minute, p < 0.001) and did not change over 9 minutes in either group. There were no differences in compression rates or number of breaks between groups.

Conclusions CCC‐CPR resulted in more adequate compressions per minute than STD‐CPR for the first 2 minutes of CPR. However, the difference diminished after 3 minutes, presumably as a result of greater rescuer fatigue with CCC‐CPR. Overall, CCC‐CPR resulted in more total compressions per minute than STD‐CPR during the entire 9 minutes of resuscitation.
Recent Development of 6π-Electrocyclic Photochromic Systems
Authors: Matsuda Kenji , Irie Masahiro
Published: October 2006

Photochromic compounds are currently recognized as the promising candidates for future optoelectronic devices, such as memories and switches. Photochemical pericyclic reactions between 1,3,5-hexatriene and 1,3-cyclohexadiene have been used in several ways to construct versatile photochromic compounds. Recent development of the 6π-electrocyclic photochromic systems is overviewed.
Synthesis of Tungsten Carbide Nanocrystal via a Simple Reductive Reaction
Authors: Guo Chunli , Liu Yi , Ma Xiaojian , Qian Yitai , Xu Liqiang
Published: October 2006

Tungsten carbide nanocrystal had been prepared by the simple reaction of WO3, Mg, and anhydrous CH3CH2OH in an autoclave at 600 °C. There were two types of tungsten carbide in the samples; one was pure WC, and the other was wrapped by carbon. Transmission electron microscopy (TEM) results revealed that the diameters of WC nanocrystals ranged from 100 to 200 nm, and that the WC nanocrystals were slightly agglomerated. The possible formation mechanism of the as-obtained tungsten carbide was discussed.
Preparation of Monetite (CaHPO4) with Hexagonally Packed Mesoporous Structure by a Sol–Gel Method Using Cationic Surfactant Aggregates as a Template
Authors: Tokuoka Yoshikazu , Ito Yasunobu , Kitahara Keiichi , Niikura Yoshihiro , Ochiai Akira , Kawashima Norimichi
Published: October 2006

We first-successfully fabricated mesoporous calcium phosphates by a regular sol–gel method using cationic surfactant aggregates as a template. Low-angle XRD and TEM observation indicated that a product included hexagonally packed mesoporous structure. Wide-angle XRD and FT-IR observation identified the product as monetite (CaHPO4), which is one of calcium phosphates.