bluuebunny/crossref_metadata_2025_split huggingface dataset:
Selection of the relevant information set for predictive relationships analysis between time series
Authors: Triacca Umberto 
Published: December 2002

AbstractIn time series analysis, a vector Y is often called causal for another vector X if the former helps to improve the k‐step‐ahead forecast of the latter. If this holds for k=1, vector Y is commonly called Granger‐causal for X. It has been shown in several studies that the finding of causality between two (vectors of) variables is not robust to changes of the information set. In this paper, using the concept of Hilbert spaces, we derive a condition under which the predictive relationships between two vectors are invariant to the selection of a bivariate or trivariate framework. In more detail, we provide a condition under which the finding of causality (improved predictability at forecast horizon 1) respectively non‐causality of Y for X is unaffected if the information set is either enlarged or reduced by the information in a third vector Z. This result has a practical usefulness since it provides a guidance to validate the choice of the bivariate system {X, Y} in place of {X, Y, Z}. In fact, to test the ‘goodness’ of {X, Y} we should test whether Z Granger cause X not requiring the joint analysis of all variables in {X, Y, Z}. Copyright © 2002 John Wiley & Sons, Ltd.
Multivariate Bayesian regression applied to the problem of network security
Authors: Triantafyllopoulos Kostas , Pikoulas John 
Published: December 2002

AbstractAn Erratum has been published for this article inJournal of Forecasting 23(6): 461 (2004).This paper examines the problem of intrusion in computer systems that causes major breaches or allows unauthorized information manipulation. A new intrusion‐detection system using Bayesian multivariate regression is proposed to predict such unauthorized invasions before they occur and to take further action. We develop and use a multivariate dynamic linear model based on a unique approach leaving the unknown observational variance matrix distribution unspecified. The result is simultaneous forecasting free of the Wishart limitations that is proved faster and more reliable. Our proposed system uses software agent technology. The distributed software agent environment places an agent in each of the computer system workstations. The agent environment creates a user profile for each user. Every user has his or her profile monitored by the agent system and according to our statistical model prediction is possible. Implementation aspects are discussed using real data and an assessment of the model is provided. Copyright © 2002 John Wiley & Sons, Ltd.
Forecasting trend output in the Euro area
Authors: Schumacher Christian 
Published: December 2002

AbstractThis paper is an applied study about forecasting trend output and the output gap in the Euro area. The need for trend output forecasts is justified by an analysis of the monetary strategy of the European Central Bank. Trend output serves as a direct inflation indicator and helps to determine the reference value for money. For both purposes, trend output has to be forecasted. A permanent–transitory decomposition based on cointegration restrictions gives an estimate of trend output in the Euro area. Ex‐ante point forecasts of trend output are computed and bootstrap simulation is employed to construct prediction intervals that take estimation uncertainty into consideration. The uncertainty of trend output and the output gap is quite large and raises questions about their usefulness as indicators for monetary policy. Copyright © 2002 John Wiley & Sons, Ltd.
An electron microprobe study of P645/T390: Evidence for an Early Helladic III Lerna–Aegina connection
Authors: Dorais Michael J. , Shriner Christine M. 
Published: December 2002

AbstractMiddle Helladic Aeginetan Ware is widely distributed throughout the Aegean. It is characterized by a “gold mica or volcanic ash” fabric and is abundant at Lerna on the Argive plain, Greece, in the Middle Helladic and Late Helladic I periods. A group of Early Helladic III ceramics at Lerna includes P645/T390, which also has a volcanic fabric. We have sampled all the major rock types of the separate volcanic episodes on Aegina, Methana, and Poros and analyzed the constituent minerals with the electron microprobe. These analyses provide a reference standard against which the mineralogy of P645/T390 and other potential Aeginetan wares can be compared. The compositions of amphibole, clinopyroxene, plagioclase, and biotite in P645/T390 are identical to the same minerals in dacites on Aegina, suggesting an origin on that island. Compositional mismatches with the minerals of Methana and Poros indicated the ceramic was not manufactured at these locations. This narrow‐necked jar represents the earliest occurrence of Aeginetan Ware on mainland Greece that has been confirmed by a quantitative method. © 2002 Wiley Periodicals, Inc.
The source of raw materials for Roman pottery from Leptiminus, Tunisia
Authors: Sherriff Barbara L. , Court Patricia , Johnston Shannon , Stirling Lea 
Published: December 2002

AbstractLeptiminus, a Roman port city on the west coast of Tunisia, North Africa, exported olive oil and a garum fish paste to Rome. Excavations have uncovered many facilities including kilns and a potter's workshop, indicating an extensive ceramic industry. The vessels, manufactured at Leptiminus, included African red‐slip fineware, coarseware, and amphorae. A petrographic study of pottery sherds showed them to contain very similar temper, rounded aeolian sand grains and limestone, but varying in proportions to produce different textures. An investigation of the source of raw materials for the pottery found three distinct types of clay within a 50 km radius of Leptiminus: grey Miocene, brown Pliocene, and green Late Pliocene clay. Statistical analysis of trace element compositions, using induced neutron activation, of clays and sherds showed that the Pliocene brown clay was used to create all types of pottery. The specific clay horizon, used in Roman times, has apparently been removed by quarrying. However, a lateral continuation of this bed was found 7 m beneath the Leptiminus site 290. © 2002 Wiley Periodicals, Inc.
Eolian processes, ground cover, and the archaeology of coastal dunes: A taphonomic case study from San Miguel Island, California, U.S.A.
Authors: Rick Torben C. 
Published: December 2002

AbstractGeomorphological evidence and historical wind records indicate that eolian processes have heavily influenced San Miguel Island environments for much of the Late Quaternary. The island is almost constantly bombarded by prevailing northwesterly winds, with peak velocities exceeding 75 km/h and wind gusts reaching over 100 km/h. These strong winds played an important role in the location, formation, and preservation of the island's more than 600 archaeological sites. Excavation and surface collection at a stratified Middle and Late Holocene archaeological site on the island's north coast suggest that wind related disturbances result in significant displacement of light fish bones, produce concentrations of shellfish and heavy mammal bones, and cause significant abrasion, etching, and polishing of bones, shells, and artifacts. These data illustrate that wind not only alters surface materials but can significantly disturb subsurface deposits to a depth of at least 20 cm. Working in concert with a variety of taphonomic processes, wind can play a fundamental role in the preservation of archaeological sites and careful scrutiny during excavation and laboratory analysis is required to delineate its effects. © 2002 Wiley Periodicals, Inc.
Statistical flattening of MEG beamformer images
Authors: Barnes Gareth R. , Hillebrand Arjan 
Published: December 2002

AbstractWe propose a method of correction for multiple comparisons in MEG beamformer based Statistical Parametric Maps (SPMs). We introduce a modification to the minimum‐variance beamformer, in which beamformer weights and SPMs of source‐power change are computed in distinct steps. This approach allows the calculation of image smoothness based on the computed weights alone. In the first instance we estimate image smoothness by looking at local spatial correlations in residual images generated using random data; we then go on to show how the smoothness of the SPM can be obtained analytically by measuring the correlations between the adjacent weight vectors. In simulations we show that the smoothness of the SPM is highly inhomogeneous and depends on the source strength. We show that, for the minimum variance beamformer, knowledge of image smoothness is sufficient to allow for correction of the multiple comparison problem. Per‐voxel threshold estimates, based on the voxels extent (or cluster size) in flattened space, provide accurate corrected false positive error rates for these highly inhomogeneously smooth images. Hum. Brain Mapping 18:1–12, 2003. © 2002 Wiley‐Liss, Inc.
Reproducibility of the hemodynamic response to auditory oddball stimuli: A six‐week test–retest study
Authors: Kiehl Kent A. , Liddle Peter F. 
Published: December 2002

AbstractDetermining the reliability and reproducibility of the hemodynamic response is important for the interpretation and understanding of the results of functional magnetic resonance imaging (fMRI) experiments. We describe a whole brain fMRI study designed to examine the reproducibility of the event‐related hemodynamic response elicited by low‐probability task‐relevant target stimuli and low‐probability task‐irrelevant novel stimuli assessed 6 weeks apart. Reliable activation was observed during test and retest for processing of target stimuli in multiple frontal, temporal, parietal, cerebellar, and subcortical sites. Novel stimuli elicited reliable activation during test and retest in lateral frontal cortex, inferior parietal lobule, and lateral temporal cortex, though there was evidence of habituation at some cortical sites. The patterns of activation associated with target detection and novelty processing are consistent with the intracranial distribution of the neural sources generated during similar tasks and replicate the results of previous event‐related fMRI studies. The observed pattern of results supports the hypothesis that the hemodynamic response to target and novel stimuli is highly reproducible over the 6‐week test–retest period. Hum. Brain Mapping 18:42–52, 2003. © 2002 Wiley‐Liss, Inc.
Posterior cingulate cortex activation by emotional words: fMRI evidence from a valence decision task
Authors: Maddock Richard J. , Garrett Amy S. , Buonocore Michael H. 
Published: December 2002

AbstractFunctional imaging studies consistently find that emotional stimuli activate the posterior cingulate cortex, a region that appears to have memory‐related functions. However, prior imaging studies have not controlled for non‐emotional stimulus features that might activate this region by engaging memory processes unrelated to emotion. This study examined whether emotional words activated the posterior cingulate cortex when these potentially confounding factors were controlled. Sixty‐four pleasant and 64 unpleasant words were matched with neutral words on non‐emotional features known to influence memory. Eight subjects underwent block‐designed functional magnetic resonance imaging scans while evaluating the valence of these words. The posterior cingulate cortex was significantly activated bilaterally during both unpleasant and pleasant compared to neutral words. The strongest activation peak with both unpleasant and pleasant words was observed in the left subgenual cingulate cortex. Anteromedial orbital and left inferior and middle frontal cortices were also activated by both pleasant and unpleasant words. Right amygdala and auditory cortex were activated only by unpleasant words, while left frontal pole was activated only by pleasant words. The results show that activation of the posterior cingulate cortex by emotional stimuli cannot be attributed to the memory‐enhancing effects of non‐emotional stimulus features. The findings are consistent with the suggestion that this region may mediate interactions of emotional and memory‐related processes. The results also extend prior findings that evaluating emotional words consistently activates the subgenual cingulate cortex, and suggest a means of probing this region in patients with mood disorders. Hum. Brain Mapping 18:30–41, 2003. © 2002 Wiley‐Liss, Inc.
Efficient acquisition of human retinotopic maps
Authors: Slotnick Scott D. , Yantis Steven 
Published: December 2002

AbstractA bifield stimulation method for rapidly obtaining retinotopic maps in human occipital cortex using functional MRI was compared to conventional unifield stimulation. While maintaining central fixation, each participant viewed the conventional display, consisting of a single rotating checkerboard wedge and, in a separate run, the bifield display, consisting of two symmetrically placed rotating checkerboard wedges (a ‘propeller’ configuration). Both stimulus configurations used wedges with 30 degree polar angle width, 6.8 degrees visual angle extension from fixation, and 8.3 Hz contrast polarity reversal rate. Retinotopic maps in each condition were projected onto a distortion corrected computationally flattened cortical surface representation obtained from a high‐resolution structural MRI. An automated procedure to localize borders between early visual areas revealed, as expected, that map precision increased with duration of data acquisition for both conditions. Bifield stimulation required 40% less time to yield maps with similar precision to those obtained using conventional unifield stimulation. Hum. Brain Mapping 18:22–29, 2003. © 2002 Wiley‐Liss, Inc.
Reducing avoidable inequalities in health: a new criterion for setting health care capitation payments
Authors: Hauck Katharina , Shaw Rebecca , Smith Peter C. 
Published: December 2002

AbstractTraditionally, most health care systems which pretend to any sort of rationality and cost control have sought to allocate their limited funds in order to secure equal opportunity of access for equal need. The UK government is implementing a fundamental change of resource allocation philosophy towards ‘contributing to the reduction of avoidable health inequalities’. The purpose of this essay is to explore some of the economic issues that arise when seeking to allocate health care resources according to the new criterion. It indicates that health inequalities might arise because of variations in the quality of health services, variations in access to those services, or variations in the way people produce health, and that the resource allocation consequences differ depending on which source is being addressed. The paper shows that an objective of reducing health inequalities is not necessarily compatible with an objective of equity of access, nor with the objective of maximising health gain. The results have profound consequences for approaches towards economic evaluation, the role of clinical guidelines and performance management, as well as for resource allocation methods. Copyright © 2002 John Wiley & Sons, Ltd.
Desmoplastic neurotropic melanoma of the head and neck: The role of radiation therapy
Authors: Anderson Timothy D. , Weber Randal S. , Guerry Dupont , Elder David , Schuchter Lynn , Loevner Laurie A. , Rosenthal David I. 
Published: December 2002

AbstractBackgroundDesmoplastic neurotropic melanoma (DNM) is an uncommon cutaneous melanoma variant with pronounced neurotropism. In contrast to ordinary melanomas, locoregional recurrences are common and distant metastasis are uncommon in patients with DNM. Local control with surgery and radiation therapy may assume a more important role in this variant of melanoma. We present a case of an unresectable skull base recurrence of DNM that was controlled using radiation therapy alone and review the literature.MethodsCase report with 36‐month follow‐up.ResultsThe patient is a 68‐year‐old with multiple recurrences of a DNM that originated on the forehead. After extensive surgery, including total parotidectomy and temporal bone resection, the patient had an unresectable recurrence of the skull base develop. This was treated with definitive radiation therapy, resulting in a complete response. The patient has had no evidence of recurrence at 3 years.ConclusionsDNM is a locally aggressive type of melanoma with a high risk of local recurrence that can be radioresponsive. The incidence of distant metastasis is low, so aggressive treatment to control local disease is warranted. This may include surgery plus adjuvant radiation therapy or definitive radiotherapy for unresectable recurrences. © 2002 Wiley Periodicals, Inc.
Direct coaptation of extensive facial nerve defects after removal of the superficial part of the parotid gland: An anatomic study
Authors: Gardetto Alexander , Kovacs Peter , Piegger Johannes , Rainer Christian , Meirer Romed , Piza‐Katzer Hildegunde 
Published: December 2002

AbstractBackground.In the surgical repair of facial nerve paralysis, a tension‐free end‐to‐end coaptation of the trunk or its branches with or without rerouting is functionally superior to grafting. Assuming that a lengthening of all branches of the parotid plexus can be attained by removal of the superficial part of the parotid gland and mobilization of the branches, we performed an anatomic study.Methods.The parotid regions of 10 cadavers were dissected to investigate the length gained for the branches of the parotid plexus by this technique. Every branch at the upper and ventral border of the gland was marked by a surgical suture. After removing the superficial part of the parotid gland, the branches were cut at the suture, and the proximal stump was drawn toward the distal stump. The distance of the overlapping stumps was measured by means of an electronic gliding caliper. In addition, in five specimens only the trunk of the facial nerve was dissected by the same method, and the distance of the overlapping stumps was measured.Results and Conclusions.The results demonstrate that removing the superficial part of the parotid gland may be sufficient to enable direct coaptation without nerve grafting. Cut temporal or zygomatic branches with a gap of up to 15 mm and cut buccal or marginal mandibular branches with a gap of up to 23 mm can be bridged by mobilization of just the proximal stumps. This technique may also be used to bridge a 17‐mm gap of the trunk of the facial nerve. © 2002 Wiley Periodicals, Inc. Head Neck 24: 1047–1053, 2002
Clinical usefulness of telomerase activation and telomere length in head and neck cancer
Authors: Patel Mintoo M. , Parekh Lalit J. , Jha Franky P. , Sainger Rachana N. , Patel Jayendra B. , Patel Devendra D. , Shah Pankaj M. , Patel Prabhudas S. 
Published: December 2002

AbstractBackground.Telomere shortening at every replication cycle is postulated to limit the life span of human somatic cells. In contrast, activation of telomerase is proposed to be an essential step for cancer cell immortalization. Head and neck cancer is the most common malignancy in the Indian population compared with Western countries. However, there are very few reports on telomerase activity and telomere length in head and neck cancer.Methods.Telomerase activation and telomere length alterations were studied in tumor and adjacent normal tissues in 110 patients with head and neck cancer and 40 patients with precancerous/benign conditions. Telomerase activity and telomere lengths were determined by Telomeric Repeat Amplification Protocol (TRAP assay) and Southern blot analysis, respectively.Results.Telomerase activation was observed in 78.2% of the malignant tissues, 85% of the precancerous tissues, and 53.1% of the adjacent normal tissues. Peak terminal restriction fragment length (TRF) was observed to be significantly lower in malignant tissues compared with the adjacent normal tissues. No significant correlation could be observed between telomerase activation and clinicopathologic characteristics of the patients. Two‐year disease‐free survival analysis showed that patients showing telomerase activation in the adjacent normal tissues and patients showing higher telomere length in malignant tissues had poor disease‐free survival.Conclusions.Our results demonstrate the significant clinical usefulness of telomerase activation and telomere length for head and neck cancer patients. These markers may be helpful in predicting the clinical course of the disease and thus in identifying the patients in need of a close follow‐up and vigorous adjuvant treatment. © 2002 Wiley Periodicals, Inc. Head Neck 24: 1060–1067, 2002
Platelet 5‐HT2A‐receptor‐mediated induction of aggregation is not altered in major depression
Authors: Gómez‐Gil Esther , Gastó Cristóbal , Díaz‐Ricart Maribel , Carretero Marta , Salamero Manel , Catalán Rosa , Escolar Ginés 
Published: December 2002

AbstractBackgroundStudies of the 5‐HT2A receptor subtype in major depression have focused on the density of these receptors in neuronal cells and platelets, showing an up‐regulation secondary to a deficit in serotonergic activity in major depression. However, their functional state has often been disregarded. The aim of the study was to investigate whether depressed patients show abnormalities in the function of the 5‐HT2A receptor pathway in platelets.MethodThe percentage of serotonin‐amplified platelet aggregation to adenosine diphosphate (ADP) was assessed in 30 untreated patients with major depressive disorder and in 15 controls. Since 5‐HT2A platelet receptors mediate the serotonin‐induced platelet aggregation response, this index was used as a measure of the functional status of the platelet 5‐HT2A receptor pathway.ResultsThere was no significant difference in the percentage of serotonin‐amplified platelet aggregation to ADP between depressed patients and controls. No correlation with the severity of depression, as assessed by the Hamilton scale, was found.ConclusionThe results showed no consistent changes in the platelet aggregating responses to serotonin in the depressed patients. Therefore this study does not support the hypothesis of an alteration of the functional status of platelet 5‐HT2A receptors in major depression. Copyright © 2002 John Wiley & Sons, Ltd.