bluuebunny/crossref_metadata_2025 huggingface dataset:
Stage-variations of anandamide hydrolase activity in the mouse uterus during the natural oestrus cycle
Authors: Klinger Francesca G , Battista Natalia , De Felici Massimo , Maccarrone Mauro
Published: April 2006

Recent studies have demonstrated that the endogenous cannabinoids are important modulators of fertility in mammals. In particular, a role of the endocannabinoid system in early stages of embryo development, oviductal transport of embryos, pregnancy maintenance and labour has been demonstrated in rodents and/or in humans. In the present paper, we report the analysis of FAAH activity and protein content in the mouse uterus as a function of the natural oestrus cycle stages. Variations of FAAH activity are discussed in relationship to changes in sex steroid levels and to the possible action of AEA on remodelling of uterine tissues.
Localization of deformed wing virus infection in queen and drone Apis mellifera L
Authors: Fievet Julie , Tentcheva Diana , Gauthier Laurent , de Miranda Joachim , Cousserans François , Colin Marc Edouard , Bergoin Max
Published: April 2006

The distribution of deformed wing virus infection within the honey bee reproductive castes (queens, drones) was investigated by in situ hybridization and immunohistology from paraffin embedded sections. Digoxygenin or CY5.5 fluorochrome end-labelled nucleotide probes hybridizing to the 3' portion of the DWV genome were used to identify DWV RNA, while a monospecific antibody to the DWV-VP1 structural protein was used to identify viral proteins and particles. The histological data were confirmed by quantitative RT-PCR of dissected organs. Results showed that DWV infection is not restricted to the digestive tract of the bee but spread in the whole body, including queen ovaries, queen fat body and drone seminal vesicles.
Evaluation of three Polymerase chain reaction tests targeting morphological transforming region II, UL-83 gene and glycoprotein O gene for the detection of Human Cytomegalovirus genome in clinical specimens of immunocompromised patients in Chennai, India
Authors: Sowmya P , Madhavan HN , Therese KL
Published: April 2006

Background

Human Cytomegalovirus (HCMV) continues to be an important cause of morbidity and occasional mortality in immunocompromised patients. Polymerase chain reaction (PCR) is the most sensitive and commonly used method for the assessment of HCMV infection in the immunocompromised patients at risk from severe associated clinical manifestations. However, there is little consistency in the qualitative PCR used for different regions of HCMV genome. Therefore, the performance of three Qualitative PCR tests to detect HCMV genome in clinical specimens from immunocompromised patients was evaluated. With pp65 antigenemia assay as the "gold standard", nested PCR for morphological transforming region II (mtr II) and glycoprotein O (gO) gene and uniplex PCR for UL 83 gene were applied on 92 consecutive clinical specimens obtained from 74 immunocompromised patients with clinically suspected HCMV disease. Virus isolation was attempted on 12 clinical specimens from six pp65 antigenemia positive patients. Based on the pp 65 antigenemia results as "gold standard", the sensitivity, specificity, positive predictive value and negative predictive value for each PCR was calculated.

Results

The PCR targeting mtr II region showed a higher sensitivity (100%) and negative predictive value (100%) than the other two PCRs in detecting HCMV DNA from clinical specimens obtained from different immunocompromised patient population of Chennai region, India.

Conclusion

The results suggests that the optimal method of detection of HCMV DNA could be achieved by PCR using primer sequences targeting mtr II region of genome of HCMV in Chennai region, India.
Toward a treaty on safety and cost-effectiveness of pharmaceuticals and medical devices: enhancing an endangered global public good
Authors: Faunce Thomas Alured
Published: April 2006

• Expert evaluations of the safety, efficacy and cost-effectiveness of pharmaceutical and medical devices, prior to marketing approval or reimbursement listing, collectively represent a globally important public good. The scientific processes involved play a major role in protecting the public from product risks such as unintended or adverse events, sub-standard production and unnecessary burdens on individual and governmental healthcare budgets.

• Most States now have an increasing policy interest in this area, though institutional arrangements, particularly in the area of cost-effectiveness analysis of medical devices, are not uniformly advanced and are fragile in the face of opposing multinational industry pressure to recoup investment and maintain profit margins.

• This paper examines the possibility, in this context, of States commencing negotiations toward bilateral trade agreement provisions, and ultimately perhaps a multilateral Treaty, on safety, efficacy and cost-effectiveness analysis of pharmaceuticals and medical devices. Such obligations may robustly facilitate a conceptually interlinked, but endangered, global public good, without compromising the capacity of intellectual property laws to facilitate local product innovations.
Tacit knowledge as the unifying factor in evidence based medicine and clinical judgement
Authors: Thornton Tim
Published: April 2006

The paper outlines the role that tacit knowledge plays in what might seem to be an area of knowledge that can be made fully explicit or codified and which forms a central element of Evidence Based Medicine. Appeal to the role the role of tacit knowledge in science provides a way to unify the tripartite definition of Evidence Based Medicine given by Sackett et al: the integration of best research evidence with clinical expertise and patient values. Each of these three elements, crucially including research evidence, rests on an ineliminable and irreducible notion of uncodified good judgement.

The paper focuses on research evidence, drawing first on the work of Kuhn to suggest that tacit knowledge contributes, as a matter of fact, to puzzle solving within what he calls normal science. A stronger argument that it must play a role in research is first motivated by looking to Collins' first hand account of replication in applied physics and then broader considerations of replication in justifying knowledge claims in scientific research. Finally, consideration of an argument from Wittgenstein shows that whatever explicit guidelines can be drawn up to guide judgement the specification of what counts as correctly following them has to remain implicit.

Overall, the paper sets out arguments for the claim that even though explicit guidelines and codifications can play a practical role in informing clinical practice, they rest on a body of tacit or implicit skill that is in principle ineliminable. It forms the bedrock of good judgement and unites the integration of research, expertise and values.
The membrane targeted apoptosis modulators erucylphosphocholine and erucylphosphohomocholine increase the radiation response of human glioblastoma cell lines in vitro
Authors: Rübel Amelie , Handrick René , Lindner Lars H , Steiger Matthias , Eibl Hansjörg , Budach Wilfried , Belka Claus , Jendrossek Verena
Published: April 2006

Background

Alkylphosphocholines constitute a novel class of antineoplastic synthetic phospholipid derivatives that induce apoptosis of human tumor cell lines by targeting cellular membranes. We could recently show that the first intravenously applicable alkylphosphocholine erucylphosphocholine (ErPC) is a potent inducer of apoptosis in highly resistant human astrocytoma/glioblastoma cell lines in vitro. ErPC was shown to cross the blood brain barrier upon repeated intravenous injections in rats and thus constitutes a promising candidate for glioblastoma therapy. Aim of the present study was to analyze putative beneficial effects of ErPC and its clinically more advanced derivative erucylphosphohomocholine (erucyl-N, N, N-trimethylpropanolaminphosphate, ErPC3, Erufosine™ on radiation-induced apoptosis and eradication of clonogenic tumor cells in human astrocytoma/glioblastoma cell lines in vitro.

Results

While all cell lines showed high intrinsic resistance against radiation-induced apoptosis as determined by fluorescence microscopy, treatment with ErPC and ErPC3 strongly increased sensitivity of the cells to radiation-induced cell death (apoptosis and necrosis). T98G cells were most responsive to the combined treatment revealing highly synergistic effects while A172 showed mostly additive to synergistic effects, and U87MG cells sub-additive, additive or synergistic effects, depending on the respective radiation-dose, drug-concentration and treatment time. Combined treatment enhanced therapy-induced damage of the mitochondria and caspase-activation. Importantly, combined treatment also increased radiation-induced eradication of clonogenic T98G cells as determined by standard colony formation assays.

Conclusion

Our observations make the combined treatment with ionizing radiation and the membrane targeted apoptosis modulators ErPC and ErPC3 a promising approach for the treatment of patients suffering from malignant glioma. The use of this innovative treatment concept in an in vivo xenograft setting is under current investigation.
Growth of a human mammary tumor cell line is blocked by galangin, a naturally occurring bioflavonoid, and is accompanied by down-regulation of cyclins D3, E, and A
Authors: Murray Tessa J , Yang Xinhai , Sherr David H
Published: April 2006

Introduction

This study was designed to determine if and how a non-toxic, naturally occurring bioflavonoid, galangin, affects proliferation of human mammary tumor cells. Our previous studies demonstrated that, in other cell types, galangin is a potent inhibitor of the aryl hydrocarbon receptor (AhR), an environmental carcinogen-responsive transcription factor implicated in mammary tumor initiation and growth control. Because some current breast cancer therapeutics are ineffective in estrogen receptor (ER) negative tumors and since the AhR may be involved in breast cancer proliferation, the effects of galangin on the proliferation of an ER-, AhRhigh line, Hs578T, were studied.

Methods

AhR expression and function in the presence or absence of galangin, a second AhR inhibitor, α-naphthoflavone (α-NF), an AhR agonist, indole-3-carbinol, and a transfected AhR repressor-encoding plasmid (FhAhRR) were studied in Hs578T cells by western blotting for nuclear (for instance, constitutively activated) AhR and by transfection of an AhR-driven reporter construct, pGudLuc. The effects of these agents on cell proliferation were studied by 3H-thymidine incorporation and by flow cytometry. The effects on cyclins implicated in mammary tumorigenesis were evaluated by western blotting.

Results

Hs578T cells were shown to express high levels of constitutively active AhR. Constitutive and environmental chemical-induced AhR activity was profoundly suppressed by galangin as was cell proliferation. However, the failure of α-NF or FhAhRR transfection to block proliferation indicated that galangin-mediated AhR inhibition was either insufficient or unrelated to its ability to significantly block cell proliferation at therapeutically relevant doses (IC50 = 11 μM). Galangin inhibited transition of cells from the G0/G1 to the S phases of cell growth, likely through the nearly total elimination of cyclin D3. Expression of cyclins A and E was also suppressed.

Conclusion

Galangin is a strong inhibitor of Hs578T cell proliferation that likely mediates this effect through a relatively unique mechanism, suppression of cyclin D3, and not through the AhR. The results suggest that this non-toxic bioflavonoid may be useful as a chemotherapeutic, particularly in combination with agents that target other components of the tumor cell cycle and in situations where estrogen receptor-specific therapeutics are ineffective.
Type I insulin-like growth factor receptor over-expression induces proliferation and anti-apoptotic signaling in a three-dimensional culture model of breast epithelial cells
Authors: Yanochko Gina M , Eckhart Walter
Published: April 2006

Introduction

Activation of the type I insulin-like growth factor receptor (IGFIR) promotes proliferation and inhibits apoptosis in a variety of cell types. Transgenic mice expressing a constitutively active IGFIR or IGF-I develop mammary tumors and increased levels of IGFIR have been detected in primary breast cancers. However, the contribution of IGFIR activation in promoting breast cancer progression remains unknown. Mammary epithelial cell lines grown in three-dimensional cultures form acinar structures that mimic the round, polarized, hollow and growth-arrested features of mammary alveoli. We used this system to determine how proliferation and survival signaling by IGFIR activation affects breast epithelial cell biology and contributes to breast cancer progression.

Methods

Pooled, stable MCF-10A breast epithelial cells expressing wild-type IGFIR or kinase-dead IGFIR (K1003A) were generated using retroviral-mediated gene transfer. The effects of over-expression of wild-type or kinase-dead IGFIR on breast epithelial cell biology were analyzed by confocal microscopy of three-dimensional cultures. The contribution of signaling pathways downstream of IGFIR activation to proliferation and apoptosis were determined by pharmacological inhibition of phosphatidylinositol 3' kinase (PI3K) with LY294002, MAP kinase kinase (MEK) with UO126 and mammalian target of rapamycin (mTOR) with rapamycin.

Results

We found that MCF-10A cells over-expressing the IGFIR formed large, misshapen acinar structures with filled lumina and disrupted apico-basal polarization. This phenotype was ligand-dependent, occurring with IGF-I or supraphysiological doses of insulin, and did not occur in cells over-expressing the kinase-dead receptor. We observed increased proliferation, decreased apoptosis and increased phosphorylation of Ser473 of Akt and Ser2448 of mTOR throughout IGFIR structures. Inhibition of PI3K with LY294002 or MEK with UO126 prevented the development of acinar structures from IGFIR-expressing but not control cells. The mTOR inhibitor rapamycin failed to prevent IGFIR-induced hyperproliferation and survival signaling.

Conclusion

Increased proliferation and survival signaling as well as loss of apico-basal polarity by IGFIR activation in mammary epithelial cells may promote early lesions of breast cancer. Three-dimensional cultures of MCF-10A cells over-expressing the IGFIR are a useful model with which to study the role of IGFIR signaling in breast cancer progression and for characterizing the effects of chemotherapeutics targeted to IGFIR signaling.
A comparison of continuous and bi-level positive airway pressure non-invasive ventilation in patients with acute cardiogenic pulmonary oedema: a meta-analysis
Authors: Ho Kwok M , Wong Karen
Published: April 2006

Introduction

We conducted the present study to investigate the potential beneficial and adverse effects of continuous positive airway pressure (CPAP) compared with bi-level positive airway pressure (BiPAP) noninvasive ventilation in patients with cardiogenic pulmonary oedema.

Method

We included randomized controlled studies comparing CPAP and BiPAP treatment in patients with cardiogenic pulmonary oedema from the Cochrane Controlled Trials Register (2005 issue 3), and EMBASE and MEDLINE databases (1966 to 1 December 2005), without language restriction. Two reviewers reviewed the quality of the studies and independently performed data extraction.

Results

Seven randomized controlled studies, including a total of 290 patients with cardiogenic pulmonary oedema, were considered. The hospital mortality (relative risk [RR] 0.76, 95% confidence interval [CI] 0.32–1.78; P = 0.52; I2 = 0%) and risk for requiring invasive ventilation (RR 0.80, 95% CI 0.33–1.94; P = 0.62; I2 = 0%) were not significantly different between patients treated with CPAP and those treated with BiPAP. Stratifying studies that used either fixed or titrated pressure during BiPAP treatment and studies involving patients with or without hypercapnia did not change the results. The duration of noninvasive ventilation required until the pulmonary oedema resolved (weighted mean difference [WMD] in hours = 3.65, 95% CI -12.12 to +19.43; P = 0.65, I2 = 0%) and length of hospital stay (WMD in days = -0.04, 95% CI -2.57 to +2.48; P = 0.97, I2 = 0%) were also not significantly different between the two groups. Based on the limited data available, there was an insignificant trend toward an increase in new onset acute myocardial infarction in patients treated with BiPAP (RR 2.10, 95% CI 0.91–4.84; P = 0.08; I2 = 25.3%).

Conclusion

BiPAP does not offer any significant clinical benefits over CPAP in patients with acute cardiogenic pulmonary oedema. Until a large randomized controlled trial shows significant clinical benefit and cost-effectiveness of BiPAP versus CPAP in patients with acute cardiogenic pulmonary oedema, the choice of modality will depend mainly on the equipment available.
Deciphering cellular states of innate tumor drug responses
Authors: Graudens Esther , Boulanger Virginie , Mollard Cindy , Mariage-Samson Régine , Barlet Xavier , Grémy Guilaine , Couillault Christine , Lajémi Malika , Piatier-Tonneau Dominique , Zaborski Patrick , Eveno Eric , Auffray Charles , Imbeaud Sandrine
Published: April 2006

Background

The molecular mechanisms underlying innate tumor drug resistance, a major obstacle to successful cancer therapy, remain poorly understood. In colorectal cancer (CRC), molecular studies have focused on drug-selected tumor cell lines or individual candidate genes using samples derived from patients already treated with drugs, so that very little data are available prior to drug treatment.

Results

Transcriptional profiles of clinical samples collected from CRC patients prior to their exposure to a combined chemotherapy of folinic acid, 5-fluorouracil and irinotecan were established using microarrays. Vigilant experimental design, power simulations and robust statistics were used to restrain the rates of false negative and false positive hybridizations, allowing successful discrimination between drug resistance and sensitivity states with restricted sampling. A list of 679 genes was established that intrinsically differentiates, for the first time prior to drug exposure, subsequently diagnosed chemo-sensitive and resistant patients. Independent biological validation performed through quantitative PCR confirmed the expression pattern on two additional patients. Careful annotation of interconnected functional networks provided a unique representation of the cellular states underlying drug responses.

Conclusion

Molecular interaction networks are described that provide a solid foundation on which to anchor working hypotheses about mechanisms underlying in vivo innate tumor drug responses. These broad-spectrum cellular signatures represent a starting point from which by-pass chemotherapy schemes, targeting simultaneously several of the molecular mechanisms involved, may be developed for critical therapeutic intervention in CRC patients. The demonstrated power of this research strategy makes it generally applicable to other physiological and pathological situations.
RNA editing of human microRNAs
Authors: Blow Matthew J , Grocock Russell J , van Dongen Stijn , Enright Anton J , Dicks Ed , Futreal P Andrew , Wooster Richard , Stratton Michael R
Published: April 2006

Background

MicroRNAs (miRNAs) are short RNAs of around 22 nucleotides that regulate gene expression. The primary transcripts of miRNAs contain double-stranded RNA and are therefore potential substrates for adenosine to inosine (A-to-I) RNA editing.

Results

We have conducted a survey of RNA editing of miRNAs from ten human tissues by sequence comparison of PCR products derived from matched genomic DNA and total cDNA from the same individual. Six out of 99 (6%) miRNA transcripts from which data were obtained were subject to A-to-I editing in at least one tissue. Four out of seven edited adenosines were in the mature miRNA and were predicted to change the target sites in 3' untranslated regions. For a further six miRNAs, we identified A-to-I editing of transcripts derived from the opposite strand of the genome to the annotated miRNA. These miRNAs may have been annotated to the wrong genomic strand.

Conclusion

Our results indicate that RNA editing increases the diversity of miRNAs and their targets, and hence may modulate miRNA function.
Linkages between atmospheric circulation, climate and streamflow in the northern North Atlantic: research prospects
Authors: Kingston D. G. , Lawler D. M. , McGregor G. R.
Published: April 2006

This paper evaluates the relationships between atmospheric circulation, climate and streamflow in the northern North Atlantic region over the last century and especially the last 50 years. Improved understanding of climatic influences on streamflow is vital given the great importance of fluvial processes to natural systems and water resources, especially in the light of recent and predicted climate change. The main focus lies with climatic and hydrologic implications of the major circulation patterns in the northern North Atlantic, namely the North Atlantic Oscillation (NAO) and Arctic Oscillation (AO). The studies reviewed here reveal key relationships between circulation, climate and streamflow across the northern North Atlantic, allowing the construction of a simple conceptual model for this system. Generally positive NAO/AO-streamflow relationships are found in northwest Europe and northeast USA, with both positive and negative NAO/AO-streamflow linkages apparent for parts of eastern Canada. To help promote a better understanding of the system, several research gaps are identified and critically examined, including: the spatial scope and coverage of investigations; data quality and homogeneity; appropriateness of analytical techniques; and the need for greater knowledge and technique sharing between hydrology and climatology, particularly regarding the rigorous characterization of atmospheric circulation patterns. Among these, the development of seasonally varying, or mobile, NAO indices, to capture variations in subseasonal, seasonal and annual movements in the centres of action, and the need to develop analyses of more hydrologically meaningful climate variables beyond conventional time averaged statistics, are deemed particularly important.
Geostatistics, spatial rate of change analysis and boundary detection in plant ecology and biogeography
Authors: Kent Martin , Moyeed Rana A. , Reid Catherine L. , Pakeman Robin , Weaver Ruth
Published: April 2006

Over the past decade, biologists and ecologists rather than geographers have been primarily responsible for developments in spatial analysis and geostatistics that are of great potential importance to both biogeography and community/landscape ecology. These advances in geostatistics, rate of change analysis and boundary detection and their application to floristic and environmental data at the community scale are reviewed. Issues of scale, spatial autocorrelation and terminology are introduced. Approaches to the description of spatial pattern in plant assemblages and environmental data, the quantification and removal of spatial autocorrelation, the spatial interpolation of data, techniques for the description and analysis of spatial rate of change and finally boundary detection are all reviewed in turn. Despite the development of new methods, the extent to which they have been applied more widely within both plant ecology and biogeography is limited. The paper concludes that perhaps the time is right for biogeographers to reassess the potential significance of these areas for the subject.
A Japanese View of the 1906 San Francisco Earthquake Disaster
Authors: Otani Shunsuke
Published: April 2006

During the period from 20 May to 26 June 1906, Professor Toshikata Sano of the Imperial University of Tokyo investigated the building damage caused by the 1906 San Francisco earthquake and fire disaster. The main findings of Sano's investigation were (1) the number of casualties was deliberately reported smaller than it was known to be by the local government, (2) the fire disaster was extensive in San Francisco, (3) the damage to buildings in San Francisco was more severe in the reclaimed land than on the hills, (4) the intensity of ground shaking was estimated to be 0.1 g on the hills and 0.25 g in the reclaimed land in San Francisco, (5) the performance of steel structures was generally good under shaking, (6) the performance of the two reinforced concrete buildings in San Francisco was good, and (7) the failure of brick and masonry construction was attributed to poor material quality and workmanship.
Probing the Evolutionary Origins of Music Perception
Authors: McDERMOTT JOSH , HAUSER MARC D.
Published: April 2006

Abstract:Empirical data have recently begun to inform debates on the evolutionary origins of music. In this paper we discuss some of our recent findings and related theoretical issues. We claim that theories of the origins of music will be usefully constrained if we can determine which aspects of music perception are innate, and, of those, which are uniquely human and specific to music. Comparative research in nonhuman animals, particularly nonhuman primates, is thus critical to the debate. In this paper we focus on the preferences that characterize most humans' experience of music, testing whether similar preferences exist in nonhuman primates. Our research suggests that many rudimentary acoustic preferences, such as those for consonant over dissonant intervals, may be unique to humans. If these preferences prove to be innate in humans, they may be candidates for music‐specific adaptations. To establish whether such preferences are innate in humans, one important avenue for future research will be the collection of data from different cultures. This may be facilitated by studies conducted over the internet.
Musical Behavior in a Neurogenetic Developmental Disorder: Evidence from Williams Syndrome
Authors: LEVITIN DANIEL J.
Published: April 2006

Abstract:This paper reviews a series of studies performed to assess the musical abilities and behaviors of individuals with Williams syndrome, a neurogenetic developmental disorder, in the hope of eventually being able to link genes, neurodevelopment, and cognition. Two questionnaire studies addressing the role of music in everyday life, and unusual reactions to sound, are described. Additionally, the findings from two empirical behavioral studies and a neuroimaging study are reviewed. The findings show that individuals with Williams syndrome tend to be more engaged in musical activities than others, and I report a possible neuroanatomical correlate of this engagement, with increased activation in the right amygdala to music and to noise. Williams syndrome represents a compelling model of the relationship between genes, brains, and such complex cognitive behaviors as music.
Structural, Functional, and Perceptual Differences in Heschl's Gyrus and Musical Instrument Preference
Authors: SCHNEIDER PETER , SLUMING VANESSA , ROBERTS NEIL , BLEECK STEFAN , RUPP ANDRÉ
Published: April 2006

Abstract: The musical pitch of harmonic complex sounds, such as instrumental sounds, is perceived primarily by decoding either the fundamental pitch (keynote) or spectral aspects of the stimuli, for example, single harmonics. We divided 334 professional musicians, including symphony orchestra musicians, 75 amateur musicians, and 54 nonmusicians, into either fundamental pitch listeners or spectral pitch listeners. We observed a strong correlation between pitch perception preference and asymmetry of brain structure and function in the pitch‐sensitive lateral areas of Heschl's gyrus (HG), irrespective of musical ability. In particular, fundamental pitch listeners exhibited both larger gray matter volume measured using magnetic resonance imaging (MRI) and enhanced P50m activity measured using magnetoencephalography (MEG) in the left lateral HG, which is sensitive to rapid temporal processing. Their chosen instruments were percussive or high‐pitched instruments that produce short, sharp, or impulsive tones (e.g., drums, guitar, piano, trumpet, or flute). By contrast, spectral pitch listeners exhibited a dominant right lateral HG, which is known to be sensitive to slower temporal and spectral processing. Their chosen instruments were lower‐pitched melodic instruments that produce rather sustained tones with characteristic changes in timbre (e.g., bassoon, saxophone, french horn, violoncello, or organ). Singers also belonged to the spectral pitch listeners. Furthermore, the absolute size of the neural HG substrate depended strongly on musical ability. Overall, it is likely that both magnitude and asymmetry of lateral HG, and the related perceptual mode, may have an impact on preference for particular musical instruments and on musical performance.
Key Processing Precedes Emotional Categorization of Western Music
Authors: FILIPIC SUZANNE , BIGAND EMMANUEL
Published: April 2006

Abstract:To investigate whether key processing precedes the appraisal of valence in music, participants listened to pairs of clips of same or different valence, played either in the same key or one semitone apart. They judged whether the second clip expressed the same emotion as the first one. Our predictions were confirmed: the response times obtained were shorter when both clips were played in the same key than when they were played one semitone apart.
Neuronal Mechanisms Underlying the Perception of Pitch and Harmony
Authors: LANGNER GERALD
Published: April 2006

Abstract: Temporal processing of periodic acoustic signals in the auditory brain stem provides an explanation for pitch perception and the natural preference of our hearing system for harmonic relationships in music. Experimental evidence is reviewed for a corresponding neuronal model of correlation analysis and the spatial representation of pitch information along the second neural axis of the auditory system.
Emotion Processing of Major, Minor, and Dissonant Chords
Authors: PALLESEN KAREN JOHANNE , BRATTICO ELVIRA , BAILEY CHRISTOPHER , KORVENOJA ANTTI , KOIVISTO JUHA , GJEDDE ALBERT , CARLSON SYNNÖVE
Published: April 2006

Abstract: Musicians and nonmusicians listened to major, minor, and dissonant musical chords while their BOLD brain responses were registered with functional magnetic resonance imaging. In both groups of listeners, minor and dissonant chords, compared with major chords, elicited enhanced responses in several brain areas, including the amygdala, retrosplenial cortex, brain stem, and cerebellum, during passive listening but not during memorization of the chords. The results indicate that (1) neural processing in emotion‐related brain areas is activated even by single chords, (2) emotion processing is enhanced in the absence of cognitive requirements, and (3) musicians and nonmusicians do not differ in their neural responses to single musical chords during passive listening.
Influence of Musical Training on Pitch Processing: Event‐Related Brain Potential Studies of Adults and Children
Authors: MORENO SYLVAIN , BESSON MIREILLE
Published: April 2006

Abstract: The aim of this experiment was to determine whether eight weeks of musical training based on pitch processing could help eight‐year‐old children detect pitch changes in language. Results show that a relatively short exposure (eight weeks) to pitch processing in music exerts some influence on pitch processing in language. Therefore, these results are in line with the hypothesis that common processes may underlie pitch processing in language and in music.
Rooted edges of a minimal directed spanning tree on random points
Authors: Bai Z. D. , Lee Sungchul , Penrose Mathew D.
Published: April 2006

For n independent, identically distributed uniform points in [0, 1]d, d ≥ 2, let Ln be the total distance from the origin to all the minimal points under the coordinatewise partial order (this is also the total length of the rooted edges of a minimal directed spanning tree on the given random points). For d ≥ 3, we establish the asymptotics of the mean and the variance of Ln, and show that Ln satisfies a central limit theorem, unlike in the case d = 2.
Large deviation probabilities for the number of vertices of random polytopes in the ball
Authors: Calka Pierre , Schreiber Tomasz
Published: April 2006

In this paper we establish large deviation results on the number of extreme points of a homogeneous Poisson point process in the unit ball of Rd. In particular, we deduce an almost-sure law of large numbers in any dimension. As an auxiliary result we prove strong localization of the extreme points in an annulus near the boundary of the ball.
On a conditionally Poissonian graph process
Authors: Norros Ilkka , Reittu Hannu
Published: April 2006

Random (pseudo)graphs GN with the following structure are studied: first, independent and identically distributed capacities Λi are drawn for vertices i = 1, …, N; then, each pair of vertices (i, j) is connected, independently of the other pairs, with E(i, j) edges, where E(i, j) has distribution Poisson(Λi Λj / ∑k=1N Λk). The main result of the paper is that when P(Λ1 > x) ≥ x−τ+1, where τ ∈ (2, 3), then, asymptotically almost surely, GN has a giant component, and the distance between two randomly selected vertices of the giant component is less than (2 + o(N))(log log N)/(-log (τ − 2)). It is also shown that the cases τ > 3, τ ∈ (2, 3), and τ ∈ (1, 2) present three qualitatively different connectivity architectures.
Exact distribution of word counts in shuffled sequences
Authors: Rødland Einar Andreas
Published: April 2006

In DNA sequences, specific words may take on biological functions as marker or signalling sequences. These may often be identified by frequent-word analyses as being particularly abundant. Accurate statistics is needed to assess the statistical significance of these word frequencies. The set of shuffled sequences - letter sequences having the samek-word composition, for some choice ofk, as the sequence being analysed - is considered the most appropriate sample space for analysing word counts. However, little is known about these word counts. Here we present exact formulae for word counts in shuffled sequences.
On regular variation for infinitely divisible random vectors and additive processes
Authors: Hult Henrik , Lindskog Filip
Published: April 2006

We study the tail behavior of regularly varying infinitely divisible random vectors and additive processes, i.e. stochastic processes with independent but not necessarily stationary increments. We show that the distribution of an infinitely divisible random vector is tail equivalent to its Lévy measure and we study the asymptotic decay of the probability for an additive process to hit sets far away from the origin. The results are extensions of known univariate results to the multivariate setting; we exemplify some of the difficulties that arise in the multivariate case.
Numerical bounds for the distributions of the maxima of some one- and two-parameter Gaussian processes
Authors: Mercadier Cécile
Published: April 2006

We consider the class of real-valued stochastic processes indexed on a compact subset ofRorR2with almost surely absolutely continuous sample paths. We obtain an implicit formula for the distributions of their maxima. The main result is the derivation of numerical bounds that turn out to be very accurate, in the Gaussian case, for levels that are not large. We also present the first explicit upper bound for the distribution tail of the maximum in the two-dimensional Gaussian framework. Numerical comparisons are performed with known tools such as the Rice upper bound and expansions based on the Euler characteristic. We deal numerically with the determination of the persistence exponent.
Optimality of randomized trunk reservation for a problem with a single constraint
Authors: Fan-Orzechowski X. , Feinberg E. A.
Published: April 2006

We study an optimal admission of arriving customers to a Markovian finite-capacity queue, e.g. an M/M/c/N queue, with several customer types. The system managers are paid for serving customers and penalized for rejecting them. The rewards and penalties depend on customer type. The goal is to maximize the average rewards per unit time subject to the constraint on the average penalties per unit time. We provide a solution to this problem based on Lagrangian optimization. For a feasible problem, we show the existence of a randomized trunk reservation optimal policy with the acceptance thresholds for different customer types ordered according to a linear combination of the service rewards and rejection costs. In addition, we prove that any 1-randomized stationary optimal policy has this structure. In particular, we establish the structure of an optimal policy that maximizes the average rewards per unit time subject to the constraint on the blocking probability of either one of the customer types or a group of customer types pooled together.
A Markovian growth-collapse model
Authors: Boxma Onno , Perry David , Stadje Wolfgang , Zacks Shelemyahu
Published: April 2006

We consider growth-collapse processes (GCPs) that grow linearly between random partial collapse times, at which they jump down according to some distribution depending on their current level. The jump occurrences are governed by a state-dependent rate functionr(x). We deal with the stationary distribution of such a GCP, (Xt)t≥0, and the distributions of the hitting timesTa= inf{t≥ 0 :Xt=a},a> 0. After presenting the general theory of these GCPs, several important special cases are studied. We also take a brief look at the Markov-modulated case. In particular, we present a method of computing the distribution of min[Ta, σ] in this case (where σ is the time of the first jump), and apply it to determine the long-run average cost of running a certain Markov-modulated disaster-ridden system.
Perturbation analysis of a variable M/M/1 queue: a probabilistic approach
Authors: Antunes Nelson , Fricker Christine , Guillemin Fabrice , Robert Philippe
Published: April 2006

In this paper, motivated by the problem of the coexistence on transmission links of telecommunications networks of elastic and unresponsive traffic, we study the impact on the busy period of an M/M/1 queue of a small perturbation in the service rate. The perturbation depends upon an independent stationary process (X(t)) and is quantified by means of a parameter ε ≪ 1. We specifically compute the two first terms of the power series expansion in ε of the mean value of the busy period duration. This allows us to study the validity of the reduced service rate approximation, which consists in comparing the perturbed M/M/1 queue with the M/M/1 queue whose service rate is constant and equal to the mean value of the perturbation. For the first term of the expansion, the two systems are equivalent. For the second term, the situation is more complex and it is shown that the correlations of the environment process (X(t)) play a key role.
Le Her with s Suits and d Denominations
Authors: Vanniasegaram Sithparran
Published: April 2006

In 2002, Benjamin and Goldman gave a complete solution to a variant of the two-player card game Le Her. We extend their result by giving optimal strategies for the authentic version played with a deck consisting of arbitrary numbers of suits and denominations. Additionally, we show that the player who has the advantage in the game when one standard deck is used does not have the advantage if nineteen or more standard decks are used.
Range of Asymptotic Behaviour of the Optimality Probability of the Expert and Majority Rules
Authors: Berend Daniel , Sapir Luba
Published: April 2006

We study the uncertain dichotomous choice model. In this model, a group of expert decision makers is required to select one of two alternatives. The applications of this model are relevant to a wide variety of areas. A decision rule translates the individual opinions of the members into a group decision, and is optimal if it maximizes the probability of the group making a correct choice. In this paper, we assume the correctness probabilities of the experts to be independent random variables selected from some given distribution. Moreover, the ranking of the members in the group is (at least partly) known. Thus, one can follow rules based on this ranking. The extremes are the expert rule and the majority rule. The probabilities of the two extreme rules being optimal were compared in a series of early papers, for a variety of distributions. In most cases, the asymptotic behaviours of the probabilities of the two extreme rules followed the same patterns. Do these patterns hold in general? If not, what are the ranges of possible asymptotic behaviours of the probabilities of the two extreme rules being optimal? In this paper, we provide satisfactory answers to these questions.
Positive Dependence and Weak Convergence
Authors: Colangelo A. , Müller A. , Scarsini M.
Published: April 2006

A more general definition of MTP2(multivariate total positivity of order 2) probability measure is given, without assuming the existence of a density. Under this definition the class of MTP2measures is proved to be closed under weak convergence. Characterizations of the MTP2property are proved under this more general definition. Then a precise definition of conditionally increasing measure is provided, and closure under weak convergence of the class of conditionally increasing measures is proved. As an application we investigate MTP2properties of stationary distributions of Markov chains, which are of interest in actuarial science.
A Diffusion Limit for Generalized Correlated Random Walks
Authors: Gruber Urs , Schweizer Martin
Published: April 2006

A generalized correlated random walk is a process of partial sums such that (X, Y) forms a Markov chain. For a sequence (Xn) of such processes in which each takes only two values, we prove weak convergence to a diffusion process whose generator is explicitly described in terms of the limiting behaviour of the transition probabilities for the Yn. Applications include asymptotics of option replication under transaction costs and approximation of a given diffusion by regular recombining binomial trees.
A Forward Algorithm for Solving Optimal Stopping Problems
Authors: Irle Albrecht
Published: April 2006

We consider the optimal stopping problem for g(Zn), where Zn, n = 1, 2, …, is a homogeneous Markov sequence. An algorithm, called forward improvement iteration, is presented by which an optimal stopping time can be computed. Using an iterative step, this algorithm computes a sequence B0 ⊇ B1 ⊇ B2 ⊇ · · · of subsets of the state space such that the first entrance time into the intersection F of these sets is an optimal stopping time. Various applications are given.
Several Types of Ergodicity for M/G/1-Type Markov Chains and Markov Processes
Authors: Liu Yuanyuan , Hou Zhenting
Published: April 2006

In this paper we study polynomial and geometric (exponential) ergodicity for M/G/1-type Markov chains and Markov processes. First, practical criteria for M/G/1-type Markov chains are obtained by analyzing the generating function of the first return probability to level 0. Then the corresponding criteria for M/G/1-type Markov processes are given, using their h-approximation chains. Our method yields the radius of convergence of the generating function of the first return probability, which is very important in obtaining explicit bounds on geometric (exponential) convergence rates. Our results are illustrated, in the final section, in some examples.
Local Linear Approximations of Jump Diffusion Processes
Authors: Jimenez J. C. , Carbonell F.
Published: April 2006

Local linear approximations have been the main component in the construction of a class of effective numerical integrators and inference methods for diffusion processes. In this note, two local linear approximations of jump diffusion processes are introduced as a generalization of the usual ones. Their rate of uniform strong convergence is also studied.
On a Continuous-State Population-Size-Dependent Branching Process and Its Extinction
Authors: Li Yuqiang
Published: April 2006

A continuous-state population-size-dependent branching process {Xt} is a modification of the Jiřina process. We prove that such a process arises as the limit of a sequence of suitably scaled population-size-dependent branching processes with discrete states. The extinction problem for the populationXtis discussed, and the limit distribution ofXt/tobtained whenXttends to infinity.
On Maxima and Ladder Processes for a Dense Class of Lévy Process
Authors: Pistorius Martijn
Published: April 2006

In this paper, we present an iterative procedure to calculate explicitly the Laplace transform of the distribution of the maximum for a Lévy process with positive jumps of phase type. We derive error estimates showing that this iteration converges geometrically fast. Subsequently, we determine the Laplace transform of the law of the upcrossing ladder process and give an explicit pathwise construction of this process.
Stabilization of an Overloaded Queueing Network Using Measurement-Based Admission Control
Authors: Leskelä Lasse
Published: April 2006

Admission control can be employed to avoid congestion in queueing networks subject to overload. In distributed networks, the admission decisions are often based on imperfect measurements on the network state. In this paper, we study how the lack of complete state information affects the system performance, by considering a simple network model for distributed admission control. The stability region of the network is characterized and it is shown how feedback signaling makes the system very sensitive to its parameters.
Limit Theorems for Moving Averages with Random Coefficients and Heavy-Tailed Noise
Authors: Kulik Rafał
Published: April 2006

We consider a stationary moving average process with random coefficients, , generated by an array, {Ct,k, t ∈ Z, k ≥ 0}, of random variables and a heavy-tailed sequence, {Zt, t ∈ Z}. We analyze the limit behavior using a point process analysis. As applications of our results we compare the limiting behavior of the moving average process with random coefficients with that of a standard MA(∞) process.
A Compound Poisson Approximation Inequality
Authors: Peköz Erol A.
Published: April 2006

We give conditions under which the number of events which occur in a sequence ofm-dependent events is stochastically smaller than a suitably defined compound Poisson random variable. The results are applied to counts of sequence pattern appearances and to system reliability. We also provide a numerical example.
A Limit Theorem for Discrete Galton-Watson Branching Processes with Immigration
Authors: Li Zenghu
Published: April 2006

We provide a simple set of sufficient conditions for the weak convergence of discrete-time, discrete-state Galton-Watson branching processes with immigration to continuous-time, continuous-state branching processes with immigration.