bluuebunny/crossref_metadata_2025_split huggingface dataset:
Assessment of short‐term association between health outcomes and ozone concentrations using a Markov regression model
Authors: Zeghnoun Abdelkrim , Czernichow Pierre , Declercq Christophe 
Published: April 2003

AbstractLongitudinal binary data are often used in panel studies where short‐term associations between air pollutants and respiratory health outcomes are investigated. A Markov regression model in which the transition probabilities depend on the covariates, as well as the past responses, was used to study the short‐term association between daily ozone (O3) concentrations and respiratory health outcomes in a panel of schoolchildren in Armentières, Northern France. The results suggest that there was a small but statistically significant association between O3 and children's cough episodes. A 10 μg/m3 increase in O3 concentrations was associated with a 13.9 % increase in cough symptoms (CI 95% = 1.2–28.1%).The use of a Markov regression model can be useful as it permits one to address easily both the regression objective and the stochastic dependence between successive observations. However, it is important to verify the sensitivity of the Markov regression parameters to the time‐dependence structure.In this study, it was found that, although what happened on the previous day was a strong predictor of what happened on the current day, this did not contradict the O3‐respiratory symptom associations. Compared to the Markov regression model, the signs of the parameter estimates of marginal and random‐intercept models remain the same. The magnitudes of the O3 effects were also essentially the same in the three models, whose confidence intervals overlapped. Copyright © 2003 John Wiley & Sons, Ltd.
Improving the precision of longitudinal ecological surveys using precisely defined observational units
Authors: Ryan Daniel A. J. , Heyward Andrew 
Published: April 2003

AbstractIn ecological longitudinal studies, it is difficult to precisely define an observational unit. In many cases the investigator must decide between permanent observational units or observational units with no permanent markers (re‐established each year). The latter choice is appealing as there are no maintenance costs, but the loss of precision in a longitudinal study can be severe. In this article, we analytically demonstrate that by not permanently and precisely marking observational units in a longitudinal study, the efficiency can be reduced, or the cost increased, or both. The magnitude of loss is illustrated for a coral reef benthic survey where precision was reduced by as much as a factor of 12. General formulae to estimate the relative efficiency of ecological surveys based on different levels of observational unit markings are also presented. Copyright © 2003 John Wiley & Sons, Ltd.
Spatial covariance modelling in a complex coastal domain by multidimensional scaling
Authors: Løland Anders , Høst Gudmund 
Published: April 2003

AbstractIn aquatic studies, spatial interactions may be both easier to interpret and to quantify by using water distance than by using geographic distance. The water distance is the shortest path between those two sites that may be traversed entirely over water. One problem is that water distances may be non‐Euclidean, and thus covariance and variogram functions are not necessarily valid when using the water distance as a distance metric. Another problem is that the computation of water distances for a large set of spatial locations is computationally expensive. Our alternative is a computationally efficient method for calculation of a Euclidean approximation to water distances. The first step of the method is to define a triangular grid covering the complex domain of interest. Using this triangular grid, we pre‐compute approximate water distances using a graph search algorithm. These water distances are then approximated by multidimensional scaling, giving a Euclidean space. Finally, we use linear interpolation to move the data locations into the new Euclidean space. By using this method, subsequent computations of water distances between any locations can be done very fast and the method leads to a theoretically valid spatial covariance model. We apply our method to herring data from the Vestfjord system in Northern Norway. Copyright © 2003 John Wiley & Sons, Ltd.
A general model for predicting brown tree snake capture rates
Authors: Engeman Richard M. , Paige Groninger N. , Vice Daniel S. 
Published: April 2003

AbstractThe inadvertent introduction of the brown tree snake (Boiga irregularis) to Guam has resulted in the extirpation of most of the island's native terrestrial vertebrates, has presented a health hazard to small children, and also has produced economic problems. Trapping around ports and other cargo staging areas is central to a program designed to deter dispersal of the species. Sequential trapping of smaller plots is also being used to clear larger areas of snakes in preparation for endangered species reintroductions. Traps and trapping personnel are limited resources, which places a premium on the ability to plan the deployment of trapping efforts. In a series of previous trapping studies, data on brown tree snake removal from forested plots was found to be well modeled by exponential decay functions. For the present article, we considered a variety of model forms and estimation procedures, and used capture data from individual plots as random subjects to produce a general random coefficients model for making predictions of brown tree snake capture rates. The best model was an exponential decay with positive asymptote produced using nonlinear mixed model estimation where variability among plots was introduced through the scale and asymptote parameters. Practical predictive abilities were used in model evaluation so that a manager could project capture rates in a plot after a period of time, or project the amount of time required for trapping to reduce capture rates to a desired level. The model should provide managers with a tool for optimizing the allocation of limited trapping resources. Copyright © 2003 John Wiley & Sons, Ltd.
Pesticide dispersion–advection equation with soil temperature effect
Authors: Paraiba Lourival Costa , Pulino Petronio 
Published: April 2003

AbstractA dispersion–advection equation, denoted as a DAPESTE model, of one‐dimensional evolution to simulate pesticide leaching in soil with a sinusoidal function to describe the daily average soil temperature at different depths is presented. In numerical simulation, the finite element method (FEM) will be used for space semi‐discretization and the regressive Eüler method (REM) for time discretization. It will be used as an FEM for dispersion–advection problems in which the advective transport predominates over the dispersive one. Let us suppose that the pesticide diffusivities in the gaseous and aqueous soil phases depend on the soil temperature. In this way, the effective hydrodynamic dispersion coefficient of the dispersion–advection equation will depend on the soil temperature. The pesticide air–water partition coefficient of the Henry law, varying with temperature, will be determined by the Clausius–Clapeyron equation. The van't Hoff equation will be used to determine the temperature dependence of the pesticide soil sorption coefficient. The Arrhenius equation will be used to estimate the effect of the soil temperature on the pesticide degradation rate. These temperature dependence relationships can help comprehend the pesticide behavior in the soil under different scenarios of the soil temperatures, especially in pesticide concentration leaching and its half‐life in soil. Copyright © 2003 John Wiley & Sons, Ltd.
Pilot‐aided acquisition algorithms for asynchronous
Authors: Xiao Pei , Ström Erik 
Published: April 2003

AbstractThe problem of estimating propagation delays of orthogonally modulated signals in asynchronous DS‐CDMA systems over time‐varing Rayleigh‐fading channels is treated in this paper. The maximum likelihood (ML) estimator and its unaffordable complexity for implementation are discussed. Some suboptimal solutions, e.g., whitened sliding correlator, MMSE estimator, subspace‐based estimator, approximate ML estimator, are proposed to combat the multiple access interference in the fading channels. The performance of these estimators are evaluated with the computer simulations and shown to have better acquisition performance than the standard sliding correlator. They also achieve reduced computational complexity compared with the ML estimator, while maintaining an acceptable performance degradation. Copyright © 2003 AEI
Combining Galois with complex field coding for space–time communications
Authors: Wang Renqiu , Wang Zhengdao , Giannakis Georgios B. 
Published: April 2003

AbstractA joint scheme combining error‐control coding (ECC) with complex‐field coding (CFC) is proposed for space–time communications through flat or frequency‐selective fading multiple‐input multiple‐output (MIMO) channels. It is shown that the diversity gain of this joint coding scheme is the product of the free distance of the ECC, the complex‐field block encoder size, and the number of receiving antennas, which is computationally prohibitive to achieve using ECC alone. The decoding complexity with the proposed iterative decoder is comparable to a system without CFC. Numerical simulations for perfectly interleaved and HIPERLAN channels with both single and multiple antennas show great potential of the proposed joint coding scheme. Copyright © 2003 AEI
Co‐channel interference mitigation in GSM networks by iterative estimation of channel and data
Authors: Lončar Maja , Mecklenbräuker Christoph F. , Müller Ralf R. 
Published: April 2003

AbstractIn multiple‐access communication systems several users share the system resources, thus creating co‐channel interference to each other. Multiuser detection, applied at the receiver side, is a powerful technique to combat co‐channel interference, in contrast to single‐user approaches that treat the interference as additive noise. In this paper, we investigate the feasibility of achieving increased spectral efficiency in GSM‐like TDMA networks by applying multiuser detection. We focus on downlink operation and consider two mobile users that share the same physical channel within the same cell or in two adjacent cells. No synchronization between the base stations is assumed. Mobile terminals exploit multiple receiving antennas. We propose a simple iterative receiver algorithm that performs joint channel and data estimation. Results of simulations that evaluate the receiver's performance are presented. Copyright © 2003 AEI
Traditions in monkeys
Authors: Perry Susan , Manson Joseph H. 
Published: April 2003

AbstractTraditions, defined as relatively long‐lasting behavioral practices shared among members of a group partly via social learning, were studied in monkeys, specifically Japanese macaques, before being studied in great apes. Although apes and humans may share some social learning capacities that are absent in monkeys, a complete understanding of the roots of human culture requires attention to the socioecological conditions favoring traditions, however generated, in animals generally and in multiple behavioral domains. Using the four criteria of intergroup variation, observation of the origin and spread of a novel behavior, dissemination patterned according to age or kinship, or individuals' close observation of others' performance of the behavior before engaging in it, over twenty‐five behaviors have been nominated as traditions in free‐ranging monkey populations. Tolerant gregariousness has been proposed to increase the likelihood of the emergence of traditions in any behavioral domain. Omnivory and extractive foraging should favor the emergence of foraging‐related traditions; strong cooperative relationships and flexible coalitionary structure should favor the emergence of social conventions that function to test social bonds. These conditions are taxonomically widespread. Thus, the current restriction of most reported free‐ranging monkey traditions to two taxa (Macaca fuscata and Cebus) is likely to reflect variation in primatologists' research goals, methods, and concepts rather than real interspecific variation in the propensity to generate traditions.
Is culture a golden barrier between human and chimpanzee?
Authors: Boesch Christophe 
Published: April 2003

AbstractCulture pervades much of human existence. Its significance to human social interaction and cognitive development has convinced some researchers that the phenomenon and its underlying mechanisms represent a defining criterion for humankind. However, care should be taken not to make hasty conclusions in light of the growing number of observations on the cultural abilities of different species, ranging from chimpanzees and orangutans to whales and dolphins. The present review concentrates on wild chimpanzees and shows that they all possess an extensive cultural repertoire. In the light of what we know from humans, I evaluate the importance of social learning leading to acquisition of cultural traits, as well as of collective meaning of communicative traits. Taking into account cross‐cultural variations in humans, I argue that the cultural abilities we observe in wild chimpanzees present a broad level of similarity between the two species.
Cultural panthropology
Authors: Whiten Andrew , Horner Victoria , Marshall‐Pescini Sarah 
Published: April 2003

AbstractCulture, in the most basic sense of “tradition,” has been shown to exist in many species. There is more to the phenomenon of culture in humans, however, than the mere existence of traditions. Thus, rather than expecting that culture can be assigned to living or ancestral species in an all‐or‐none fashion, reconstruction of the evolution of this uniquely complex phenomenon is likely to depend on successfully teasing apart its components, which may have evolved in a somewhat mosaic fashion. In this paper, we dissect ten different aspects of human culture and offer evidence that most of them are manifested in chimpanzees, even if in limited ways, permitting inferences about the cultural profile of our common ancestor. The aspects of culture examined include large‐scale patterns of behavioral variation across populations, the mechanisms available for social transmission, and cultural contents. The contrasts thus drawn for humans and chimpanzees offer a framework for cultural comparisons between other taxa from the past and present.
The evolution of culture: New perspectives and evidence
Authors: Janson Charles H. , Smith Eric A. 
Published: April 2003

AbstractThis and the next issue of Evolutionary Anthropology are devoted to presenting the most recent advances in our understanding of the evolution of culture in non‐human primates and humans. This effort was stimulated in part by the recent explosion of comparative evidence for extensive communicative and material culture in two great apes, chimpanzees1 and orangutans.2 Before this evidence accumulated, it was easy for anthropologists to maintain that examples of non‐human primate culture were little more impressive than those put forward for many other non‐human species, and thus they could leave intact the seemingly huge gap between animal and human culture. The overall purpose of this special pair of issues of Evolutionary Anthropology is to ask how and why culture has changed over evolutionary time from non‐primates to non‐human primates to early hominins to modern humans.
Genetic alterations in primary cutaneous CD30+ anaplastic large cell lymphoma
Authors: Mao Xin , Orchard Guy , Lillington Debra M. , Russell‐Jones Robin , Young Bryan D. , Whittaker Sean 
Published: April 2003

AbstractPrimary cutaneous CD30+ anaplastic large cell lymphoma (C‐ALCL) represents a distinct clinical subtype of CD30+ anaplastic large cell lymphomas. The etiology and underlying molecular pathogenesis of C‐ALCL remain unclear. This study aimed to investigate genetic changes in C‐ALCL. Comparative genomic hybridization (CGH) analysis of 23 DNA samples from 15 C‐ALCL cases identified chromosome imbalances (CI) in 10 samples from eight cases (43%). The mean number of CI per sample was 2.09 ± 3.86, with gains (2.00 ± 3.85) more common than losses (0.09 ± 0.29). The most frequent CI were gains of 1/1p and 5 (50%) and 6, 7, 8/8p, and 19 (38%). Microarray‐based CGH analysis of six DNA samples from five cases with CI revealed genomic imbalances (GI) in all of the cases studied. This included oncogene copy number gains of FGFR1 (8p11) in three cases, and NRAS (1p13.2), MYCN (2p24.1), RAF1 (3p25), CTSB (8p22), FES (15q26.1), and CBFA2 (21q22.3) in two cases. Real‐time PCR analysis of nine DNA samples from eight cases with CI and GI detected amplifications of CTSB and RAF1 in seven cases (88%), REL (2p13p12) and JUNB (19p13.2) in six cases (75%), and MYCN and YES1 (18p11.3) in four cases (50%). Immunohistochemical staining of paraffin sections from six cases demonstrated expression of JUNB protein in five cases and BCL2 in three cases. These results reveal a consistent pattern of genetic alterations in C‐ALCL and provide the molecular basis for further investigation of this disease. © 2003 Wiley‐Liss, Inc.
Chromosomal instability in pancreatic ductal cells from patients with chronic pancreatitis and pancreatic adenocarcinoma
Authors: Moskovitz Alexander H. , Linford Nancy J. , Brentnall Teresa A. , Bronner Mary P. , Storer Barry E. , Potter John D. , Bell Richard H. , Rabinovitch Peter S. 
Published: April 2003

AbstractPancreatic adenocarcinoma is a disease with high mortality for which chronic pancreatitis confers a markedly increased risk. We hypothesize that chromosome instability and genomic damage occur in pre‐neoplastic pancreatic ductal epithelium, and that this damage may be related to oxidative stress. We used dual‐color fluorescence in situ hybridization with centromere probes and locus‐specific arm probes for chromosome arms 11q, 17p, and 18q to identify genomic instability in cultures of normal‐appearing human pancreatic ductal epithelium from normal organ donor controls compared to patients with chronic pancreatitis or pancreatic adenocarcinoma. To examine early pancreatic tumorigenesis, we studied only normal‐appearing pancreatic ductal cells adjacent to pancreatitis or carcinoma. We found that, compared to the finding in normal controls, chromosomal abnormalities are present in normal‐appearing human pancreatic ductal epithelia obtained from patients with chronic pancreatitis or pancreatic adenocarcinoma. Furthermore, these chromosomal abnormalities could be induced in cultured pancreatic ductal epithelium from normal organ donors by chronic exposure to dilute hydrogen peroxide, suggesting that oxidative stress may contribute to the development of chromosomal instability in the pancreas. These results elucidate a potential mechanism linking chronic pancreatitis to pancreatic cancer and suggest that chromosomal instability may be an early event in the pathogenesis of pancreatic cancer. © 2003 Wiley‐Liss, Inc.
The presence of multiple regions of homozygous deletion at the CSMD1 locus in oral squamous cell carcinoma question the role of CSMD1 in head and neck carcinogenesis
Authors: Toomes Carmel , Jackson Andrew , Maguire Kristie , Wood Joseph , Gollin Susanne , Ishwad Chandramohan , Paterson Ian , Prime Steven , Parkinson Kenneth , Bell Sandra , Woods Geoffrey , Markham Alexander , Oliver Richard , Woodward Robert , Sloan Philip , Dixon Michael , Read Andrew , Thakker Nalin 
Published: April 2003

AbstractWe and others previously identified a region of hemizygous or homozygous deletion at chromosome band 8p23 in oral and oropharyngeal squamous cell carcinomas (OSCCs) and many other cancer types, suggesting the presence of a tumor‐suppressor gene (TSG) in this region. Recently, based on a single region of homozygous deletion in head and neck squamous cell carcinomas (HNSCC), a putative TSG, CUB and sushi multiple domains‐1 (CSMD1), has been identified. In the present study, we mapped three OSCC cell lines with previously described homozygous deletions at a high resolution onto a detailed physical map. Critically, this map covered a wider region than that used in previous studies, and in contrast to these studies, our results revealed multiple regions of homozygous deletion within a small interval on 8p23. To investigate this deletion pattern further, we generated a panel of 34 sequence tagged site (STS) markers spanning the region and tested these three cell lines and an additional 34 OSCC cell lines, identifying homozygous deletions in a further four. Combining the results from all seven deleted cell lines identified three non‐overlapping regions of homozygous deletion. This complex pattern could be consistent with the presence of multiple TSGs or one very large TSG in this region, and/or specific chromosomal instability. CSMD1 spans two of the three deleted regions and, therefore, would appear to be an excellent candidate for a TSG. However, deletion mapping with STSs corresponding to the exons of CSMD1 shows that some of the deletions do not interrupt its coding region, and in other cell lines the coding region is interrupted by two discontinuous homozygous deletions, suggesting the presence of redundant deletions. These results call into question whether the CSMD1 gene is the 8p23 TSG or whether this or any other genes at this locus are involved in the development of OSCC. © 2003 Wiley‐Liss, Inc.
Peculiar structure and location of 9p21 homozygous deletion breakpoints in human cancer cells
Authors: Florl Andrea R. , Schulz Wolfgang A. 
Published: April 2003

AbstractThe CDKN2A tumor‐suppressor gene in chromosome band 9p21 encoding CDKN2A (also known as p16, INK4A), a negative regulator of cyclin‐dependent kinases, and p14ARF1, an activator of TP53, is inactivated in many human cancers by point mutations, promoter hypermethylation, or deletions. Homozygous deletions predominate in certain cancer types (e.g., bladder cancers). To understand why deletions are unusually prevalent at this locus, deletions in bladder and renal cancer cell lines were mapped in detail and several deletion breakpoints cloned. Deletions were interstitial and encompassed 0.1 to >30 Mb. Most deletion breakpoints were located in or close to LINE‐1 retrotransposon clusters. Therefore, deletions of CDKN2A may be facilitated by the presence of LINE‐1 clusters that flank the locus. All cloned junctions were products of non‐homologous recombination and consistently contained exact 2‐bp microhomologies. Microhomologies are otherwise hallmarks of DNA double‐strand break repair by non‐homologous end joining, but the consistent size found at the CDKN2A deletion junctions is difficult to reconcile with the known properties of this process. Therefore, an unknown mechanism appears to be involved in the generation of CDKN2A deletions during carcinogenesis. © 2003 Wiley‐Liss, Inc.