bluuebunny/crossref_metadata_2025_split huggingface dataset:
Sir Edward Appleton and early ionosphere research
Authors: Wilkes M. V. 
Published: June 2004

The earliest suggestion that there might be a conducting layer in the earth's atmosphere was made in 1839 by Gauss, who was concerned to explain the diurnal geomagnetic phenomena, and who pointed out that a possible hypothesis was that they arose from electric currents encircling the earth somewhere in the atmosphere. However, at that time, no mechanism to account for the existence of a conducting layer could be suggested, nor was there any knowledge of how air could become conducting; indeed, until ionizing radiation began to be studied, it was even suggested that air naturally became conducting at low pressure.
It was soon apparent that the propagation of radio waves beyond the horizon could not be explained as the result of diffraction. Heaviside and Kennelly, at about the same time, both proposed that a conducting layer in the atmosphere was responsible. It was Appleton who first showed, by an elegant and well planned series of experiments, that this was indeed the case; or to put it more precisely, that at a point distant from the transmitter there was, in addition to a wave received along the surface of the earth, a second wave descending from the sky.
Design and analysis of pilot studies: recommendations for good practice
Authors: Lancaster Gillian A. , Dodd Susanna , Williamson Paula R. 
Published: June 2004

AbstractPilot studies play an important role in health research, but they can be misused, mistreated and misrepresented. In this paper we focus on pilot studies that are used specifically to plan a randomized controlled trial (RCT). Citing examples from the literature, we provide a methodological framework in which to work, and discuss reasons why a pilot study might be undertaken. A well‐conducted pilot study, giving a clear list of aims and objectives within a formal framework will encourage methodological rigour, ensure that the work is scientifically valid and publishable, and will lead to higher quality RCTs. It will also safeguard against pilot studies being conducted simply because of small numbers of available patients.
Primary cutaneous CD30+ anaplastic large cell lymphoma with keratoacanthoma‐like pseudocarcinomatous hyperplasia and marked eosinophilia and neutrophilia
Authors: Lin Jeng‐Hsien , Lee J. Yu‐Yun 
Published: June 2004

Background:  Pseudocarcinomatous hyperplasia (PCH) and marked tissue neutrophilia have been observed in cutaneous CD30+ anaplastic large cell lymphoma (ALCL) occasionally and may cause misdiagnosis.Methods:  An unusual case of CD30+ ALCL of the skin resembling keratoacanthoma (KA) both clinically and pathologically was described. Histologic examination and immunostaining were performed.Results:  A 55‐year‐old woman presented with a 3‐month history of an enlarging hyperkeratotic tumor on the forehead with a central keratinous plug. Microscopic examination showed epithelial hyperplasia resembling KA and a diffuse background infiltrate of large atypical lymphoid cells in the dermis. The atypical cells resembled epithelial cells and were obscured by a massive infiltrate of eosinophils and neutrophils. Immunostaining confirmed the presence of a diffuse infiltrate of CD30+ cells; these cells were negative for CD45RO, CD20, CD15, epithelial membrane antigen, anaplastic lymphoma kinase‐1, and cytokeratin. There was no evidence of extracutaneous involvement. The findings were consistent with primary cutaneous CD30+ ALCL of null cell phenotype with KA‐like epithelial hyperplasia and marked eosinophilia and neutrophilia.Conclusions:  Our case illustrates that primary cutaneous ALCL may be associated with KA‐like PCH and concurrent marked tissue eosinophilia and neutrophilia. Diagnosis in such cases is challenging both clinically and histologically because the large atypical lymphoid cells may easily be obscured by the massive infiltrates of eosinophils and neutrophils or confused with invasive squamous cell carcinoma.
Cutaneous metastasis: a clinical, pathological, and immunohistochemical appraisal
Authors: Saeed Sadia , Keehn Connie A. , Morgan Michael B. 
Published: June 2004

Background:  Cutaneous tumor metastasis may be the first manifestation of cancer, but more often is a harbinger of advanced disease that portends an ominous prognosis. All skin accessions over the past 10 years from a large Veterans Administration (VA) hospital were reviewed.Methods:  Archived histories, glass slides, and the immunohistochemical battery (IHC), were assessed to determine diagnostic accuracy.Results:  Of the 100,453 cases reviewed, there were a total of 77 cases (75 males and 2 females) of cutaneous metastasis from the lungs (28.6%), metastatic melanoma (18.2%), gastrointestinal tract (14.2%), genitourinary tract (10.4%), head and neck (9.1%), hematologic (5.2%), breast (5.2%), and miscellaneous (<2%). Metastasis represented the first indication of an internal malignancy in 7.8% of cases. The cutaneous sites of involvement included the head and neck (28%), the trunk (40%), the extremities (18%), and multiple sites (14%). The age range was 38–83 years, with a mean of 62 years. The average time interval between diagnosis of internal malignancy and cutaneous presentation was 33 months (range: <1 month−22 years), and the average survival following diagnosis was 7.5 months (range: <1 month−8 years). In a cohort of subjects, a truncated immunohistochemical battery consisting of CK‐7, CK‐20, and S‐100 was consistent with the expected staining pattern of the primary source of cutaneous metastasis in 83.33% of the patients.Conclusions:  Excluding the potential for age and gender bias in this study conducted in a VA setting, cutaneous metastases represent an uncommon, deadly, and late‐developing occurrence in many patients. Compared with previous studies, lung carcinoma remains the most common of the cutaneous metastases, with a relative rise in the incidence of metastatic melanoma. The immunohistochemical battery of CK‐7, CK‐20, and S‐100 is a helpful adjunct in narrowing the differential diagnosis of the primary site of a large proportion of cutaneous metastases, particularly tumors with an epithelioid appearance such as carcinomas and melanomas.
Perilesional vs. lesional skin changes in senile lentigo
Authors: Cario‐Andre Muriel , Lepreux Sebastien , Pain Catherine , Nizard Carine , Noblesse Emmanuelle , Taïeb Alain 
Published: June 2004

Background:  Senile lentigo (SL) is a common component of photoaged skin. It is characterized by hyperpigmented macules which affect chronically irradiated skin mostly after 50 years of age. This study was undertaken to assess the basic morphology of SL on dorsum of hands.Methods:  A systematic comparison between lesional vs. perilesional skin using immunohistochemistry and electron microscopy was done to detect precursor lesions of SL and to determine whether melanocytes or keratinocytes were first affected in the evolution of lesions.Results:  In 12 cases studied, the main findings show that clusters of perilesional keratinocytes accumulate melanin in large melanosomial complexes, and that melanocytes counts are increased respective to total length of section in lesional skin, but the increment is probably due to the development of characteristic epidermal rete ridges. Melanocytes had overall a normal ultrastructure, with mostly quiescent features in perilesional skin and melanosomial transport seeming more active in lesional skin.Conclusions:  Our data indicate that SL may represent a loss of epidermal melanin unit homeostasis due to chronic irradiation, where keratinocytic changes predominate over melanocytic changes. We hypothesize that abnormal pigment retention in keratinocytes is the primary defect in SL, which may partly explain the therapeutic effect of retinoids.
Human MHC class I chain related (MIC) genes: their biological function and relevance to disease and transplantation
Authors: Collins R. W. M. 
Published: June 2004

SummaryMajor histocompatibility complex (MHC) class I chain related (MIC) molecules show homology with classical human leukocyte antigen (HLA) molecules, but they do not combine with β2 microglobulin, do not bind peptide and are not expressed on normal circulating lymphocytes. In response to stress, MIC proteins are expressed on the cell surface of freshly isolated gastric epithelium, endothelial cells and fibroblasts and engage the activating natural killer cell receptor NKG2D, which is found on many cells within the immune system. Despite the highly polymorphic nature of MIC genes, only one polymorphic position has been identified that appears to affect the binding of NKG2D. Alleles with a methionine at codon 129 have a 10–50‐fold greater capacity to complex NKG2D than alleles with a valine at this position. Renal and pancreatic grafts with evidence of both acute and chronic rejection have been shown to express MIC proteins, and anti‐MIC antibodies have been identified in the serum of these patients. Some MIC molecules which are expressed by tumours appear to shed and solubilize in plasma. This soluble form of MIC engages cells expressing NKG2D, rendering them inactive, and impairs tumour cytolysis. Similarly, a protein encoded by human cytomegalovirus (CMV) prevents MICB surface expression and subsequent NKG2D interaction. Whereas the benefit of solid organ transplantation may be hindered by the expression of MIC molecules on grafts, tumours and viruses may take advantage of the expression of MIC molecules on transformed and virus‐infected cells in order to evade this recognition pathway.
Evaluating association and transmission of eight inflammatory genes with Viliuisk encephalomyelitis susceptibility
Authors: Oleksyk T. K. , Goldfarb L. G. , Sivtseva T. , Danilova A. P. , Osakovsky V. L. , Shrestha S. , O'Brien S. J. , Smith M. W. 
Published: June 2004

SummarySince the discovery of Viliuisk encephalomyelitis (VE) in 1887, scientists have tried to understand the natural history and aetiology of this endemic neurological disorder among the native Sakha population of Central Siberia. Familial aggregation and segregation analysis suggested a genetic influence on VE incidence. However, recent studies have implicated an unknown virus, possibly from the alpha herpesvirus family, as a possible cause for this disease. As VE is a neurological disease characterized by the inflammatory reactions systematically observed in the spinocerebellar fluid and in the brain tissue of deceased patients, we examined 17 single nucleotide polymorphisms (SNPs) across seven inflammation‐related candidate gene regions, including chemokine receptors type 2 and 5 (CCR2/CCR5), interferon‐γ (IFN‐γ), interleukin‐4 (IL‐4), IL‐6, IL‐10, stromal cell‐derived factor (SDF) and chemokine regulated upon activation, normal T‐cell expressed and presumably secreted (RANTES). Our main objective was to analyse the degree of genetic association between VE and candidate genes that have been previously implicated in other inflammatory diseases. Samples were collected from 83 affected families comprising 88 verified VE cases, 156 family members, and an additional 69 unrelated, unaffected inhabitants of the same geographical area. This collection included substantially all of the cases that are currently on the VE Registry. The experimental design included both case–control and transmission/disequilibrium test (TDT)‐based familial association analyses. None of 17 SNPs analysed was significantly associated with VE occurrence. Exclusion of these eight genes based on the lack of association has important implications for identifying the disease agent, as well as prescribing therapy and understanding Viliuisk encephalomyelitis.
Speciation in the Central American Seaway: the importance of taxon sampling in the identification of trans‐isthmian geminate pairs
Authors: Craig Matthew T. , Hastings Philip A. , Pondella Daniel J. 
Published: June 2004

AbstractAim To create a molecular phylogenetic hypothesis for the closely related serranid generaAlphestesBloch and Schneider andDermatolepisGill and assess the role of the Panamanian Isthmus in speciation within these reef fishes.Location Tropical eastern Pacific, Caribbean, and Indian Oceans.Methods Sequence data from one nuclear (TMO‐4C4) and three mitochondrial genes (16S, 12S, and cytochromeb) were used in maximum parsimony and maximum likelihood analyses.Results Here we show that previously hypothesized trans‐isthmian geminate species are not each other's closest living relatives. Species ofAlphestesBloch and Schneider in the eastern Pacific are sister taxa indicating post‐closure speciation. WithinDermatolepisGill, we identify a sister group relationship between the Caribbean and western Indian Ocean species, a rarely reported biogeographic pattern. Based on sequence divergence, speciation among the three species ofDermatolepiswas, however, nearly simultaneous around the time of the isthmian closure event.Main conclusions Our molecular phylogenetic analysis of two closely related genera of reef fishes, each with presumed trans‐isthmian geminates, cautions against the uncritical use of morphological similarity in identification of geminates, as well as the assumption that trans‐isthmian sister groups date to the isthmian closure event. These findings suggest that in some instances incomplete sampling of species within a clade including putative geminates may lead to improper conclusions regarding the pattern and timing of speciation, as well as incorrect estimation of the rate at which evolution has proceeded.
Representing species in reserves from patterns of assemblage diversity
Authors: Araújo M. B. , Densham P. J. , Williams P. H. 
Published: June 2004

AbstractAim  A positive relationship between assemblage diversity (AD) – equivalent to the biotic version of the environment diversity, ED, method – and species diversity has been reported. This being true, reserve networks with many different assemblages would be expected to represent more species than reserve networks including fewer and less different assemblages. This idea was tested using European species atlas distributions of terrestrial vertebrates and plants. It is asked whether: (1) maximizing AD within one group would represent species diversity of this group better than expected by chance; and (2) maximizing AD within one group would represent species diversity of other groups better than expected by chance.Location  Europe.Methods  Three ordination techniques (non‐metric multidimensional scaling, detrended correspondence analysis and correspondence analysis) are used to summarize patterns of compositional turnover within assemblages. p‐Median location‐allocation models are then calculated from ordination space to measure the degree of expected species representation within the group being sampled as well as the expected representation within other groups. Results are compared with near‐optimal solutions obtained with complementarity‐based algorithms and to a null model obtained by simulating selection of areas at random. Matrix correlation analysis was also performed to investigate broad patterns of covariation in compositional turnover of assemblages of species belonging to different taxonomic groups and these values were compared with correlation in species richness scores between groups.Results  The AD model did not always represent more species of the group being sampled than expected by chance (P < 0.05). Results were independent of the method and taxonomic group considered. Effectiveness of AD within one group to represent species of other groups varied, but in most cases it was worse than using complementarity‐based algorithms as a surrogate strategy. Even when correlations indicated high coincidence between assemblages, taxonomic‐based surrogates did not always recover more species than expected by chance (P < 0.05).Main conclusions  Results are discussed in the light of two possible explanations: (1) the AD model is based on unrealistic assumptions, namely that species have equal probability of having the centre of their distributions anywhere in ordination space and that species display unimodal, symmetrical, bell‐shaped response curves to gradients; (2) particular implementation of methods may be inadequate to summarize useful complementarity among assemblages, especially for restricted‐range species. We conclude that both arguments are likely to play a role in explaining results, but that opportunities exist to improve performance of existing surrogate strategies.
Regional biogeography of shallow reef fish and macro‐invertebrate communities in the Galapagos archipelago
Authors: Edgar G. J. , Banks S. , Fariña J. M. , Calvopiña M. , Martínez C. 
Published: June 2004

AbstractAim  To delineate biogeographical patterns in Galapagos shallow‐water reef fauna at regional scales.Location  Galapagos Islands.Methods  Fishes and macro‐invertebrates were quantitatively censused using underwater visual techniques along more than 500 transects at defined depth strata across the Galapagos archipelago. Data were analysed using multivariate techniques to define regional patterns and identify species typical of different regions.Results  Subtidal communities of fishes and macro‐invertebrates on shallow reefs differed consistently in species composition across the Galapagos archipelago, with three major biogeographical groupings: (1) the ‘far‐northern area’ containing the islands of Darwin and Wolf, (2) the ‘central/south‐eastern area’, including the east coast of Isabela, and (3) the ‘western area’, encompassing Fernandina and western Isabela. In addition, the northern islands of Pinta, Marchena and Genovesa form a separate region in the central/south‐eastern area, and Bahia Elizabeth and Canal Bolivar separate from other parts of the western area. The far‐northern bioregion is characterized by high fish species richness overall, including a high proportion of species of Indo‐Pacific origin. However, very few endemic fishes or species with distributions extending south from Ecuador (‘Peruvian’ species) are present, and the bioregion also possesses relatively low species richness of mobile macro‐invertebrate taxa. By contrast, the ‘western’ bioregion possesses disproportionately high numbers of endemic fish taxa, high numbers of cool‐temperate Peruvian fish species, and high invertebrate species richness, but very few species of Indo‐Pacific origin. The Bahia Elizabeth/Canal Bolivar bioregion possesses more endemic species and fewer species with Peruvian affinities than coasts within the western bioregion. The northern bioregion of Pinta, Marchena and Genovesa represents an overlap zone with affinities to both the far‐northern and south‐eastern islands. The south‐eastern bioregion includes species from a variety of different sources, particularly ‘Panamic’ species with distributions extending north to Central America.Main conclusions  On the basis of congruent divisions for reef fish and macro‐invertebrate communities, the Galapagos archipelago can be separated into three major biogeographical areas, two of which can be further subdivided into two regions. Each of these five bioregions possesses communities characterized by a distinctive mix of species derived from Indo‐Pacific, Panamic, Peruvian and endemic source areas. The conservation significance of different regions is not reflected in counts of total species richness. The regions with the lowest overall fish species richness possess a temperate rather than tropical climate and highest levels of endemism.
The distribution of divergent mitochondrial DNA lineages of threespine stickleback (Gasterosteus aculeatus) in the northeastern Pacific Basin: post‐glacial dispersal and lake accessibility
Authors: Johnson Lisa S. , Taylor Eric B. 
Published: June 2004

AbstractAim This study furthers the documentation of the geographical distribution of two divergent (c. 3%) mitochondrial DNA clades in the threespine stickleback (Gasterosteus aculeatus) and tests the hypotheses that the northeastern Pacific distribution has been influenced by post‐glacial colonization and lake elevation and that clade identity is associated with certain morphological attributes such as reduction in body armour.Location Lakes and nearshore marine environments of the eastern Pacific Basin from southcentral Alaska to southeastern British Columbia, (BC) Canada.Methods Restriction enzyme analysis of polymerase chain reaction‐amplified mitochondrial DNA fragments (cytochromeb) from a total of 45 new populations combined with existing data for a further 45 populations. Lake elevation data were collected for 78 localities and tested for an association with mtDNA clade by contingency table analyses. Morphological data were collected on sticklebacks from eight samples representing four lake‐stream systems and tested for differentiation among populations with different mtDNA clade identities using analyses of variance.Results We extend the known distribution of the haplotypes diagnostic of the Trans‐North Pacific Clade (TNPC) southward to mid‐Vancouver Island and, for the first time, on mainland BC, in other island populations far from putative refugia, and in nearby anadromous populations. A morphological analysis indicated that the mainland population with the TNPC was not characterized by reduced spine or lateral plate (‘armour’) traits that characterize some putative relict populations on the Queen Charlotte Islands. We found a significant association between lake elevation and the presence of the TNPC; the TNPC was present more often in lakes located at or lower than 42 m than in higher elevation lakes.Main conclusions Our data support the hypothesis that post‐glacial colonization by TNPC‐bearing marine sticklebacks and aspects of lake ‘accessibility’ were important in determining the distribution of mtDNA clades in the eastern Pacific Ocean basin. More generally, our study demonstrates how processes acting both across immense geographic scales (e.g. pan‐Pacific dispersal) and local scales (lake accessibility contingent on timing and extent of isostatic rebound) may interact to explain biogeographical patterns.