bluuebunny/crossref_metadata_2025 huggingface dataset:
Three popular myths about language development
Authors: Kamhi Alan G.
Published: November 2007

Important clinical decisions are based in part on the information parents provide about their children's developmental language history. There are several myths about speech and language development, however, that cause parents to provide inaccurate information. Three of these myths are discussed in this paper: the First Word myth, the 'Older Sibling as Inter preter' myth, and the First Sentence myth. Familiarity with the mis conceptions that underlie these myths should help clinicians notice when parents might be providing inaccurate developmental language informa tion. The ability to recognize an inaccurate parental report should eliminate the diagnostic enigmas associated with these myths and thereby lead to more accurate diagnoses and appropriate intervention decisions.
Speaking and writing: young children's use of connectives
Authors: Raban Bridie
Published: November 2007

The investigation reported here seeks reasons for the frequent use of and in young children's writing. Comparisons between their speech and writing are reported, and further data from opportunities to write at length and from books written for children learning to read are also considered. Children at an early age were found to differentiate between speech and writing, and evidence is found which questions the value of the traditional language experience approach to the early stages of writing.
Reducing vowel and fiinal consonant prolongations in twin brothers
Authors: Hargrove Patricia M. , Dauer Kathleen E. , Montelibano Michelle
Published: November 2007

This study describes a training programme designed to reduce the frequency of vowel and final consonant prolongations in a pair of 4-year-old identical twin brothers. The goal was accomplished through the implementation of 11 objectives and a variety of training procedures. The boys' progress was evaluated by their performances in spontaneous speech and on a naming task.
The needs of teachers of children with speech and language disorders
Authors: Miller Carol
Published: November 2007

This paper outlines the chief findings about the needs of teachers of children with speech and language disorders, as emerged from a DES-funded project at the University of Birmingham into the develop ment of a distance-taught course. Teachers responded to questionnaires concerning the desirability of particular topics in such a course. A summary of their responses is given, and an analysis made of their preferences.
Preventing spelling disabilities
Authors: Glenn Patricia , Hurley Sandra Rollins
Published: November 2007

This paper synthesizes the results of research from the fields of psycholinguistics and education into the nature of the process of acquisition of spelling skills, and provides insights into some cases of dysorthographia. The spelling problems of some children appear to have resulted from the early adoption of an unusual reading strategy. This strategy, and its attendant spelling disability, may have resulted when these children began the reading process in a state of phonological unreadiness. Specific suggestions for classroom instruction in reading and spelling are derived from the research. These techniques, if adopted, would prevent or alleviate the spelling disability of children who exhibit the symptoms described.
Approaches to the development of language and communication with children who have speech and language disorders
Authors: Jacklin Angela
Published: November 2007

This paper presents the findings of a small-scale classroom-based research project. It was designed to attempt to explore the interrela tionship of approaches used by therapists and teachers in the develop ment of language and communication with children who have speech and language disorders. In particular, emphasis is given to trying to understand the way in which children 'make use' of what they are taught as a way in to evaluating the effectiveness of the approaches used.
What's in a name? Comparative therapy for word-finding difficulties using semantic and phonological approaches
Authors: Wright Susan Hyde , Gorrie Barbara , Haynes Corinne , Shipman Anne
Published: November 2007

The effect of two therapy methods in the treatment of word-finding problems during a confrontational picture-naming situation are com pared in two groups of severely language-impaired children. A treat ment technique that promotes the strengthening of the children's seman tic networking and encourages the use of self-cuing (semantic treatment) is contrasted with an approach that fosters the child's phonological awareness and supports the use of phonological self-cuing (phonologic al treatment). A course of 15 sessions of treatment over five weeks is undertaken by each subject. The results are measured one week after the end of treatment. Those subjects receiving the semantic treatment indicate a highly significant improvement in naming untrained pictures, but the phonological treatment group makes no significant improve ment. Reasons for this and the efficacy of the two methods is examined, and possible clinical implications are discussed.
Integration of a pupil from a language unit into the host school: a case study
Authors: Marshman Alison , Miller Carol
Published: November 2007

This case study examines the integration of a pupil from a language unit located in a mainstream school into classes in the host school. Data was gathered through observation, examination of written information, and semi-structured interviews. The study concludes that careful planning, parental involvement, ancillary provision, effective communication, and the availability of support and training for mainstream teachers are essential. It also recognizes that, for some pupils, speech and language difficulties may have long-term effects requiring additional provision after leaving a unit.
Working on both sides of the fence: the effect of a dual qualification on collaborative working practice
Authors: Newman Sally
Published: November 2007

Being a therapist and a teacher affects collaborative working practice in many ways. The most crucial factor which changed when the author began working as a teacher was her view of how teachers develop language skills through classroom work. If therapists are to advise teachers on how children with speech and language difficulties may be helped, then understanding the teacher's perspective on language is crucial. This paper examines what this perspective is, and how it may influence joint therapist/teacher work with children.
Screening for early language delay in the 18-36 month age-range: the predictive validity of tests of production, and implications for practice
Authors: Boyle James , Gillham Bill , Smith Nicola
Published: November 2007

Research evidence reveals that the processes of production and compre hension are not functionally discrete before around 28 months. The implications for the predictive validity of standardized screening tests which involve production, particularly those using 'flexible object naming', are considered. Examples of multiphasic and monophasic language screening tests suitable for use with children in the 18-36 month age range are reviewed, and theoretical and empirical issues underlying the development of the First Words and First Sentences tests are explored.
A prelingually deaf child's acquisition of spoken vocabulary in the first year of multichannel cochlear implant use
Authors: Willis Suzi , Edwards Jo
Published: November 2007

Professionals working with prelingually, profoundly deaf children with cochlear implants must be able to give both qualitative and quantitative information regarding vocabulary acquisition and all areas of language development. The following investigation is an initial attempt to address this need. This single subject study evaluated a 4-year-old, prelingually, profoundly deaf child's acquisition of receptive and expressive spoken vocabulary in the first year of multichannel cochlear implant use. Three standardized assessments were utilized to evaluate these areas of langu age development. A prelingually deaf child, after 12 months of cochlear implant use can be described as having a 'hearing age' of 12 months. It was hypothesized that the subject of this study would be more likely to acquire vocabulary at a rate similar to that of a hearing-age control, rather than that of a chronological-age control. In order to test this hypothesis, comparisons were made with standardized data for nor mally-hearing children. It was found that this child acquired vocabulary at approximately twice the rate of a hearing age control.
Promoting the communication skills of children with moderate learning difficulties
Authors: Lamb Susannah J. , Bibby Peter A. , Wood David J.
Published: November 2007

This paper presents the results of an intervention programme designed to promote the communication skills of a group of children with moderate learning difficulties. Thirty children were involved in a 12-week programme of supported peer-communication activities which aimed to improve the children's regulatory skills during peer interaction. By the end of the pro gramme, the children were talking more, asking more appropriate questions and responding to ambiguous utterances more effectively. The results of the study demonstrate that a programme for children with learning difficulties in which pairs of children working together are encouraged to use and reflect on regulatory strategies can provide an effective context for intervention.
New Directions in Interdisciplinarity: Broad, Deep, and Critical
Authors: Frodeman Robert , Mitcham Carl
Published: November 2007

Aristotle launched Western knowledge on a trajectory toward disciplinarity that continues to this day. But is the knowledge management project that began with Aristotle adequate for the age of Google? Perhaps an undisciplined discourse more evocative of Plato can help us constitute new, more relevant inter- and transdisciplinary forms of knowledge. This article explores the history of disciplinarity and interdisciplinarity, arguing for a new, critical form of interdisciplinarity that moves beyond the academy into dialogue with the public and private sectors. Contemporary knowledge production should involve not only a horizontal axis stretching across academia but also a vertical axis where academic research is integrated into contemporary life.
Holocene environmental changes in Namibia inferred from pollen analysis of swamp and lake deposits
Authors: Scott L. , Cooremans B. , de Wet J.S. , Vogel J.C.
Published: November 2007

Spring deposits exposed during building operations in downtown Windhoek, and lake sediments retrieved from underneath 50 m of water in a sinkhole (Lake Otjikoto), contain pollen profiles which reflect environmental changes in Namibia during the Holocene. At Windhoek moist local conditions are reflected by pollen in the spring deposits which were radiocarbon-dated to between ca. 7000 and 6000 BP. They remained relatively favourable until 5630 BP despite signs of drying. Weedy Compositae (Lactucoideae or Liguliflorae) increased until the end of this record ca. 2410 BP, indicating local disturbance. Deposits from Lake Otjikoto were dated to the late Holocene although an accurate chronology could not be estabiished for the sequence due to unexpected results with radiocarbon measurements. Pollen accumulation values and composition indicate relatively dry conditions after 3500 BP which were followed temporarily by a wetter climate during more recent times.
Late Holocene sea-level changes from grain-size data: evidence from the Gulf of Mexico
Authors: Tanner William F.
Published: November 2007

Grain-size kurtosis of sand in the beach ridge plain of St. Vincent Island, Florida, is numerically reasonably uniform within any one ridge set, but changes at important set boundaries. Where these changes are found, there are also differences in air photo and field appearance and in measured ridge-set heights. Sets with low kurtosis (∼3.0) stand topographically high, and sets with higher values (∼3.6) stand low. Study of wave energy levels and beach sand grain-size kurtosis along modem Gulf of Mexico beaches shows that kurtosis is an inverse function of surf-zone energy density.

Storms and storminess (for the study area) can be evaluated in the framework of the selective- transport model of May (1973); the actual data sequence is greatly different from what is required by the model, and therefore storms and storminess cannot be invoked to explain the history of the area. Instead, the data sequence matches results predicted by the model for small sea-level changes. Storms and tectonism do not have appropriate durations and rates of operation, hence did not cause changes in kurtosis across St. Vincent Island. Slow land elevation changes (warping, isostatic adjustment) do not take place repeatedly up and down like the granulometric parameters. Tidal effects, in the study area, are both much too small and too frequent to have been important.

The changes in kurtosis therefore indicate water level changes, and provide a sea-level history, including three sea level drops and four rises, of 1-3 m each, since about 3000 BP. Similar results have been obtained elsewhere, so these results are not local.
The climate of the last 2000 years in southern Africa
Authors: Tyson P.D. , Lindesay J.A.
Published: November 2007

Until recently, relatively little was known of the exact nature of climatic change in southern Africa over the past two millennia. New research based on oxygen isotope analyses of cave speleothems and mollusc remains in shell middens, together with foraminifera studies of inshore marine deposits, palynological and micromammalian research and earlier dendrochronological work, has allowed more reliable identification of the effects of the 'Little Ice Age' in the subcontinent. Cooling prevailed from 1300 to 1850 with a warm episode occurring between about 1500 and 1675. In addition, the generally warmer period from about 900 to 1300 may have been associated with the Medieval Warm Epoch. Earlier distinctive events appear to have been a variable period of cooling from 600 to 900, a warmer period from about AD 250 to 600 and a notable interval of cooling between AD 100 and 200.

Much of the evidence for the 'Little Ice Age' in southern Africa suggests that in the summer rainfall region drier conditions prevailed during the period of cooling. At the same time the winter rainfall region became wetter. This supports a previous postulation that as the tropical easterlies of the general circulation of the atmosphere strengthen and become more perturbed over southern Africa over extended periods, so the climate becomes wetter over the summer rainfall area. As the circumpolar westerlies strengthen and expand northward, so the summer rainfall region becomes drier, while the coastal Mediterranean winter rainfall region becomes wetter.
The palaeosalinity and vegetational history of Garaet el Ichkeul, northwest Tunisia
Authors: Stevenson A.C. , Phethean S.J. , Robinson J.E.
Published: November 2007

Palaeoecological studies of a 14C-dated, 6 m Livingstone core collected from Lac Ichkeul, N. Tunisia have allowed a palaeosalinity and vegetational history record for the last 3000 years to be derived from pollen, chemical and faunal evidence. The lake has been the subject of at least three different salinity regimes; saline (c. 3000 BP-c. 2000 BP), then brackish - fresh (c. 2000 BP-c. 1500 BP), and finally saline (c. 1500 BP-present). These changes in lake salinity are evaluated in the light of the known causes and the implications for the long-term future of the waterfowl populations discussed. An already disturbed Mediterranean woodland dominated by Quercus (cf. Q. suber) and Pinus (possibly P. halepensis) with a significant amount of Phillyrea characterizes the catchment vegetation from c. 3000 BP. From c. 1900 BP a degree of stabilization and regeneration occurs as woodland reinvades and ruderal indicators decline. However, from c. 1400 BP disturbance recommences and Quercus ilex pollen is seen for the first time. This is followed by further woodland interference resulting in the initial rise of Pistacia, but even this is eventually replaced by grassland as intensive cultivation of the Ichkeul catchment for Olea and winter wheat occurs.
An 8000-year record of sea-level change from grain-size parameters: data from beach ridges in Denmark
Authors: Tanner William F.
Published: November 2007

The low-energy beach ridge system near the town of Jerup, in the extreme north of Denmark, was sampled at 154 sites, on a pattern of one per ridge (intervals of 50-51 years, starting about 7800 BP). None of these ridges was built by storm waves or by wind. They are not like high-energy ridges to the north, which differ in size, morphology, bedding and granulometry.

In the low-energy system, sand grain-size kurtosis (inverted) is a reliable index of wave energy density in the surf zone, and also indicates an important component of settling. Kurtosis tends to be more-or-less constant in sets of 5-20 ridges, then to change abruptly at set boundaries, which therefore represent sea- level changes (1-5 m), centuries apart. The sixth moment measure (grain size) and ridge spacing also indicate sea-level change. Glacio-isostatic rebound has averaged 2 to 2.1 mm yr-1 for this system; the history of this rebound plots best on a semi-log diagram showing a decrease from about 4 mm yr-1 (at 6000 BP) to about 1.3 mm yr-1 (at 1000 BP).

The Jerup sea-level curve matches the Gulf of Mexico curve as far back as the latter goes. Each provides sea level history in the 'Little Ice Age' (most recent millennium), and other changes since 3000 BP; the Jerup curve shows earlier fluctuations. The largest changes were in the range 3-5 m; maximum rates were about 1 cm yr-1 .
A new hypothesis for the Holocene appearance of coccolithophores in the Black Sea
Authors: Jones Glenn A.
Published: November 2007

A recent accelerator mass spectrometer (AMS) radiocarbon study of Black Sea Holocene sediments has resolved a long-standing chronology controversy involving radioisotope and varve- counting methodologies. The revised chronology combined with model results of the salinity evolution of the Black Sea since the last glacial maximum does not support the hypothesis of a salinity-controlled Holocene invasion of the Black Sea by coccolithophores, a planktonic golden-brown unicellular marine algae. Rather, evidence presented here is used to suggest these organisms were inadvertently transported from the Mediterranean Sea by sailing vessels during the Greek exploration and colonization of the Black Sea in the seventh and eighth centuries BC. As such this may be one of the earliest examples of anthropogenic transport of marine organisms between ocean basins, and a good example of the difficulties inherent in distinguishing natural from anthropogenic effects when studying Holocene biological systems.
Transformation of a northern hardwood forest by aboriginal (Iroquois) fire: charcoal evidence from Crawford Lake, Ontario, Canada
Authors: Clark J.S. , Royall P.D.
Published: November 2007

Ecologists have long debated whether Indian burning had important impacts on presettlement forests. We obtained stratigraphic evidence for fire using charcoal analysis of southern Ontario lake sediments. The record spans a period of Iroquois occupation when cultivation coincides with pollen evidence for transition from northern hardwoods to white pine/oak forests. Charcoal data reveal that this transition was attended by increased charcoal accumulation, sufficiently high to suggest vegetation fires. Results support the notion that Indian burning is capable of producing dramatic changes in forest composition spanning centuries.
Problems associated with correlating calibrated radiocarbon-dated pollen diagrams with historical events
Authors: Dumayne Lisa , Stoneman Rob , Barber Keith , Harkness Doug
Published: November 2007

Problems of reconciling events registered in radiocarbon-dated pollen diagrams with calendar- dated archaeological events have been encountered when interpreting pollen diagrams constructed from a number of mire sites in the Hadrianic-Antonine frontier zone of Roman Britain. Only at Fozy Moss, Northumbria, is it possible to relate a substantial clearance in the radiocarbon-dated pollen diagram to a particular event in the calendar-dated archaeological record; in this case the Roman occupation of northern Britain and the building of Hadrian's Wall. The limitations encountered with such an approach are highlighted - too few dates and lack of precision as a result of sample size and calibration - and their implications discussed.
Reconstructing the climate of Mexico from historical records
Authors: O'Hara Sarah L. , Metcalfe Sarah E.
Published: November 2007

There is a growing number of studies that use historical sources to reconstruct recent environmental change. In Mexico there are abundant sources of information that can be used to determine variations in the climate over the historical period. In this paper we draw together information from a variety of primary and secondary historical sources to reconstruct fluctuations in the climate of central Mexico over the last 600 years. The Aztecs are believed to have entered the Basin of Mexico during a period of severe drought. Wet conditions, however, characterized much of the Aztec (AD 1345-1521) and early colonial period prior to a return to drier conditions in the 1640s. Between 1640 and 1915, a series of severe droughts caused widespread devastation throughout central Mexico, particularly during the mid- to late 1700s and late 1800s. Since the early 1900s this region has experienced slightly wetter conditions. The climatic record from the Basin of Mexico is compared with proxy climatic data from two other areas in Mexico: a detailed lake-level curve from Lake Patzcuaro in central Mexico and the few tree-ring records from northern Mexico. Although the palaeoclimatic records from central Mexico are similar, there is greater divergence between the records from central and northern Mexico. In general, fluctuations in the climate over the last 600 years can be explained by changes in the relative strength of the summer 'monsoon', but it is possible that ENSO events can cause considerable differences in prevailing climate conditions in the northern and central parts of the country.
Recent Holocene changes in sedimentation in a landslide-dammed lake in the Cascade Mountains, southwestern British Columbia, Canada
Authors: Goff J.R. , Hicock S.R. , Hamilton T.S.
Published: November 2007

Landslide-damming of Silver Lake in the Cascade Mountains took place about 1000BP. Delta growth favoured the faulted west valley side. At the commencement of logging activity in AD 1946 the course of Silverhope Creek was diverted away from access roads. As a consequence, the channel shifted from the west to the east side of the valley, forming a new delta. Six gravity lake cores and SCUBA surveys of lake sediments reveal changes in the depositional regime. In two cores, late Pleistocene-early Holocene sediments are pre served. Old delta abandonment, new delta growth, reorientation of turbidity channels and confluence zones are discussed. 137Cs data show that, following channel diversion, little or no further deposition occurred on the old delta. Assuming that the 1964 137Cs maximum has been recorded in each core, sedimentation rates appar ently decrease to the NNW, away from the new delta, and 137Cs values increase northwards. Stratigraphy, 14C and 137Cs dates indicate that there has been a recent increase in sedimentation rate of about 20 times near the deltas, to about 10 times in a mid-lake location. Erosion and the release of destabilized glaciolacustrine valley- side sediments into the creek enhances sedimentation in Silver Lake. Unstable sediments on steep valley sides prohibit forest regrowth.
The Neolithic transition in the Balkans - archaeological perspectives and palaeoecological evidence: a comment on Willis and Bennett
Authors: Edwards Kevin J. , Halstead Paul , Zvelebil Marek
Published: November 2007

Willis and Bennett have argued that palynological evidence from southeastern Europe fails to substantiate archaeological arguments for a 'Neolithic transition'. In this response, we argue that Willis and Bennett ignore the complexity of the pattern and process of Neolithiciz ation in southeastern Europe and that the available palynological evidence is inadequate to address such issues.
A Holocene vegetation history from lowland Guatemala
Authors: Islebe Gerald A. , Hooghiemstra Henry , Brenner Mark , Curtis Jason H. , Hodell David A.
Published: November 2007

A 5.45-m core from Lake Peten-Itza, lowland Guatemala, contains a near-complete record of Holo cene sedimentation. The age-depth relationship for the core is based on AMS 14C dating of terrestrial wood fragments and provides a reliable chronology in this karst region where hard-water lake error has typically confounded sediment geochronology. In the basal part of the sequence, pollen of the Moraceae-Urticaceae group dominate, indicating the presence of widespread tropical forest during the early Holocene (c. 8600-5600 yr BP). Relative abundance of pollen of high forest taxa declined beginning as early as 5600 yr BP, indicating climatic drying or perhaps initial land clearance. Deforestation by prehistoric Mayan inhabitants is documented clearly in the pollen record beginning about 2000 yr BP (106 cal BC-122 cal AD, 95.4%, 2 sigmas) by the appearance of disturbance taxa (e.g. Ambrosia and Poaceae) and presence of Zea. Forest regrowth occurred following the Classic Maya collapse, c. AD 900, as reflected by a relative increase in Moraceae-Urticaceae pollen.
Holocene vegetation of the Central Saharan Mountains: the end of a myth
Authors: Thinon Michel , Ballouche Aziz , Reille Maurice
Published: November 2007

Since the end of the 1950s it has generally been accepted that, during the mid-Holocene humid period, the central Saharan mountain vegetation (Ahaggar, Tassili-n-Ajjer and Tibesti) was clearly Mediterranean or even forest in nature. In addition to the present-day elements growing in North Africa the flora was supposed to have included some European arboreal species. This concept was mainly based on the results of pollen analysis. More recent pollen and macrofossil analysis of organic sediments from the Ahaggar massif show that mid-Holocene flora was actually very similar to that found at the present day. Earlier studies had included analysis of sediment contaminated by pollen transported long distances which had accumulated over a period of 4000 years. An endemic olive (Olea laperrini) and the Atlas pistachio tree (Pistacia atlantica), two species which are still well represented nowadays, dominated the vegetation. The new data question the extension of the Mediterranean vegetation towards the south and the amplitude of the associated climatic change.
Modelling long-term anthropogenic erosion of a loess cover: South Downs, UK
Authors: Favis-Mortlock David , Boardman John , Bell Martin
Published: November 2007

There is growing archaeological evidence that erosion induced by prehistoric agricultural activities has, in many parts of Europe, greatly thinned an original thick loess cover. The evidence for this is, however, almost entirely observational and qualitative. Whether in the time available, anthropogenic activity could have produced modern thin loessial soils has not been quantitatively evaluated. This study adopts a novel modelling approach in the estimation of long-term rates of soil loss and textural modification under prehistoric and historic tillage practices. The EPIC (Erosion-Productivity Impact Calculator) model is used to simulate the effects of erosion on a hillslope in the UK South Downs from 7000 BP to the present day. Results suggest that the major period of soil loss was between 4000 and 1800 BP under conditions of gradually intensifying agriculture following permanent clearance; that land-use rather than climate appears to be the main factor influencing past erosion rates; and that a 'thin' loess cover of c. 1.2 m is a more likely initial condition at 7000 BP than a thicker cover. Despite the tentative nature of the data used to construct the land-use and climate stages and original loessial profiles, the model succeeds in reproducing the decreased thickness and increased stoniness of present-day South Downs soils. Time series of simulated erosion and change in soil stoniness appear self- consistent and broadly plausible. The methodology therefore appears promising as a tool for testing hypotheses regarding past erosion rates.
The role of farming in the postglacial expansion of beech and hornbeam in the oak woodlands of central Europe
Authors: Küster Hansjörg
Published: November 2007

Beech did not spread simultaneously in different parts of central Europe. Therefore a climatic deterio ration can hardly account for an oak decline and a subsequent beech expansion. From the fifth millennium BC onwards, farming activities and shifting colonization are reflected by pollen analysis. At the same time, beech became more frequent in many landscapes. As a consequence of the transition from shifting to permanent colonization in the early Middle Ages the expansion of beech came to an end. Trees that could better withstand intensive human impact, such as hornbeam, were then favoured.
A 200-year record of gale frequency, Edinburgh, Scotland: possible link with high-magnitude volcanic eruptions
Authors: Dawson Alastair G. , Hickey Kieran , McKenna John , Foster D.L.
Published: November 2007

Most research concerned with the relationship between volcanic activity and global climate change has focused on the impacts that volcanoes have on atmospheric temperature. Very little attention, however, has been given to the effect of volcanic eruptions on patterns of storminess. Here we present a historical record of gale-day frequency for Edinburgh, Scotland, extending from AD 1780 to 1988 (the Mossman-Hickey chronology), which we believe represents the longest historical record of gales in Europe. Calculation of gale- day frequency for this time interval shows three clear peaks in storminess that follow the volcanic eruptions of Tambora (1815), Krakatoa (1883) and El Chichon (1982). It appears that the greatest periods of storminess evident in the Edinburgh record during the last 200 years have taken place during relatively short intervals following major episodes of volcanism. If correct, the processes linking high-magnitude volcanic eruptions to storminess in the North Atlantic need to be included in IPCC research that presently focuses most attention on linkages between increased storminess and the effects of global warming.
Structural equation models in medical research
Authors: Bentler PM , Stein JA
Published: November 2007

Structural equation modelling (SEM) is a modern statistical method that allows one to evaluate causal hypotheses on a set of intercorrelated nonexperimental data. The sample variances and covariances, and possibly the means, are compared to those predicted by a theory-based hypothetical model after optimal estimation of the parameters of the model. The goodness-of-fit of the empirical data to the hypothesized model is evaluated statistically. This review describes the underlying statistical theory and rationale of SEM. Both confirmatory factor analysis and latent variable path models are discussed. The applicability of SEM to assessment of reliability and validity is noted. A detailed example is provided, and several examples from the medical literature are briefly reviewed. Cautions regarding the possible misuse or misinterpretation of the technique are also mentioned. Possible future directions for the use of SEM in medical research are suggested. Two appendices provide more technical details.
Review papers : The statistical basis of meta-analysis
Authors: Fleiss JL
Published: November 2007

Two models for study-to-study variation in a meta-analysis are presented, critiqued and illustrated. One, the fixed effects model, takes the studies being analysed as the universe of interest; the other, the random effects model, takes these studies as representing a sample from a larger population of possible studies. With emphasis on clinical trials, this paper illustrates in some detail the application of both models to three summary measures of the effect of an experimental intervention versus a control: the standardized difference for comparing two means, and the relative risk and odds ratio for comparing two proportions.
Metabolic images from dynamic positron emission tomography studies
Authors: O'Sullivan F.
Published: November 2007

A dynamic sequence of positron emission tomography (PET) images gives rise to the possibility of creating images of in vivo tissue metabolism. For this reason PET is potentially a valuable instrument in the study of human biology and medicine. The analysis of dynamic PET data to produce metabolic images is a challenging problem from a statistical point of view. For example, a typical data set arising in the study of cerebral glucose utilization has on the order of 30 time-binned images per cross-sectional slice of tissue under examination, each of dimension 128 x 128 pixels. Metabolic imaging requires that the time series at each pixel, known as the time activity curve (TAC), be analysed to produce an estimate of local metabolism. This paper describes a mixture analysis approach to the construction of such metabolic images. In the approach the TAC at a given pixel is expressed as a weighted sum of sub-TACs corresponding to homogeneous tissues represented at the pixel. Estimates of tissue metabolism at the pixel are then constructed as a weighted sum of the metabolism associated with the individual sub-TACs. The procedure is illustrated by application to a [F-18]-labelled deoxyglucose study in a patient with a brain tumour. The ability to map simultaneously a range of parameters related to the transport and biochemical transformation of the radio-tracer, demons trates the potential power of dynamic PET.
Multi-period crossover trials
Authors: Matthews Jns
Published: November 2007

This paper presents a review of crossover designs for use in medical applications which have three or more treatment periods. Only outcomes which can be analysed as continuous variables are considered. Designs which purport to allow for carryover effects are reviewed in detail, as are methods for analysing data collected in such trials. In practice, it is often possible to eliminate carryover by interposing sufficiently long 'washout' periods between successive treatments, and suitable designs for this case are also mentioned. Much current practice revolves around a model which has been widely criticized: the shortcomings of this model and the implications of possible remedies, for design as well as analysis, are discussed.
Design issues in cohort studies
Authors: Prentice Ross L.
Published: November 2007

Some basic features of cohort studies are reviewed along with a brief discussion of relative risk estimation procedures. This background, and a discussion of factors influencing cohort study power, provides a context to examine various cohort study design choices, including the choice of study population, the selection of cohort size and follow-up duration, cohort ascertainment and subsampling choices, and decisions concerning validation and reliability substudies. It is noted that confounding issues, and especially issues related to measurement error in the assessment of primary exposure and confounding variables, may have a major influence on the precision and reliability of cohort study analyses. A brief discussion is provided of the role of cohort studies in relation to other observational and experimental research strategies.
Design issues in case-control studies
Authors: Wacholder Sholom
Published: November 2007

The most difficult and most important considerations in planning the protocol of a case-control study are ascertainment of cases, selection of controls and the quality of the exposure measurement. Plans to ensure careful field work are equally important; without attention to data collection, the protocol will be meaningless. In most case-control studies, the measurement problem is magnified because one cannot implement the collection of exposure information at the beginning of follow-up, and instead must rely on interviews, existing records or extrapolation into the past. Consideration of a case-control study as an efficient way to study a cohort helps to resolve some design issues.
Latent class analysis in medical research
Authors: Formann Anton K , Kohlmann Thomas
Published: November 2007

In the introduction we give a brief characterization of the usual measures for indicating the quality of diagnostic procedures (sensitivity, specificity and predictive value) and we refer to their relationship to parameters of the latent class model. Different variants of latent class analysis (LCA) for dichotomous data are described in the following: the basic (unconstrained) model, models with parameters fixed to given values and with equality constraints on parameters, multigroup LCA including mixed-group vali dation, and linear logistic LCA including its relationship to the Rasch model and to the measurement of change in latent subgroups. The problem with the identifiability of latent class models and the possi bilities for statistically testing their fit are outlined. The second part refers to latent class models for polytomous data. Special attention is paid to simple variants having fixed and/or equated parameters and to log-linear extension of LCA with its possibility for including interactions on the latent level. Several examples are presented to illustrate typical applications of the model. The paper ends with some warnings that should be taken into consideration by potential users of LCA.
Renal Pelvic Carcinoma with Unusual Appearance Simulating Amyloidosis (Myeloma Kidney)
Authors: Hes Ondrej , Michal Michal , Kinkor Zdeněk , Čuřík Romuald , Baumruk Luděk
Published: November 2007

We describe 5 cases of urothelial carcinoma (UC) of the renal pelvis, which grew in a distinctive gross and microscopical pattern into the renal parenchyma. Five patients (2 men and 3 women, mean age 67.4 years) underwent nephrectomy for vague clin ical findings. The cut surface of the tumor was white to light gray and the consistency was elastic. The corticomedullary border was indistinct, resulting in an appearance that suggested amyloidosis or myeloma. The renal pelvis showed normal mucosa with areas of dysplastic changes. The tumors spread from the renal pelvis in a diffuse and irregular, infiltrative pattern and surrounded intact glomeruli. Detailed sampling of invasive tumor component showed foci of UC with transitions to clear squamous cells. The predominant clear squamous neoplastic cells had foci of granular eosinophilic cytoplasm and resembled conventional renal cell carcinoma. Four pa tients were alive and without signs of the disease for 5 months to 4 years after nephrectomy; 1 died of generalized tumor 7 months after nephrectomy. The unusual gross and microscopic features result in varied problems in differential diagnosis, which are discussed herein. Int J Surg Pathol 10(1):41-45, 2002
Endocervicosis of the Small Intestine
Authors: Chen Karl T. K.
Published: November 2007

A case of endocervicosis of the small intestine incidentally found as a mass lesion dur ing a gastric bypass surgery is reported. No previous cases of intestinal endocervico sis have been reported in the literature. Int J Surg Pathol 10(1):65-67, 2002
Plexiform Spitz Nevus
Authors: Clarke B. , Essa A. , Chetty R.
Published: November 2007

In 1999, Spatz et al. reported the first 2 cases of a plexiform variant Spitz nevus. We describe another case of this variant on the upper thigh of a 10-year-old boy and dis cuss the differential diagnosis. Histologically, it comprised nodules of epithelioid cells with a plexiform arrangement distributed throughout the superficial and deep der mis. The cells had moderate eosinophilic cytoplasm with vesicular nuclei and promi nent nucleoli. Intranuclear inclusions were present focally. The tumor nodules were embedded in a myxoid stroma with intratumoral and peritumoral inflammatory cells including both lymphocytes and eosinophils. There were occasional melanin- containing spindle-shaped cells. An intraepidermal component could not be assessed, since the lesion was ulcerated. The differential diagnosis includes both melanocytic and nonmelanocytic lesions exhibiting a plexiform pattern of growth as well as myx oid lesions. Int J Surg Pathol 10(1):69-73, 2002
Clinicopathologic Significance of Cathepsin B and Urokinase-type Plasminogen Activator Immunostaining in Colorectal Adenocarcinoma
Authors: Visscher Daniel W. , Sloane B. , Sakr Wael , Sameni M. , Weaver D. , Bouwman D. , Crissman John D.
Published: November 2007

Acetone-fixed cryostat sections of 52 colorectal adenocarcinomas (26 stage B, 26 stage C) were immunostained with antibodies for two "invasion-associated" proteolytic enzymes—cathepsin B and urokinase-type plasminogen activator. Cathepsin B immu nostaining of neoplastic cells was observed in 21 tumors (40%). It was generally accompanied by staining among peritumoral host cells. There was no correlation be tween neoplastic cell cathepsin B staining and tumor stage (stage B, 42% positive vs stage C, 38% positive) however staining was more frequent in tumors that recurred (cathepsin B negative, 23% recurred vs cathepsin B positive, 48% recurred, P = .05-.06,25 months follow-up). Significant neoplastic cell urokinase-type plasminogen activator staining was present in only six cases (12%); however, peritumoral spindle and inflammatory cells exhibited positivity in 35% of tumors. There was no correlation between host cell derived urokinase-type plasminogen activator staining and either node metastasis or patient outcome. Tumors that stained for both neoplastic cell ca thepsin B and stromal cell urokinase-type plasminogen activator (12%) characterized a morphologically and clinically aggressive subset, compared to cases that stained for only one (51%) or neither (37%) enzyme (both positive, 83% recurred, 83% poorly differentiated vs neither positive, 26% recurred, 5% poorly differentiated). These data imply that invasion-associated proteases are derived from heterogeneous cellular sources in colorectal tumors. Further, synergistic protease activity may promote aggres sive clinical behavior accounting, in part, for the adverse prognostic significance of poor differentiation. Int J Surg Pathol 1(4):227-234, 1994
Immunohistochemical Detection of Toxocaral Antigens in Human Liver Biopsies
Authors: De Brito T. , Chieffi P.P. , Peres B.A. , Santos R.T. , Gayotto L.C.C. , Regina Vianna M. , Porta G. , Alves V.A.F.
Published: November 2007

The distribution of Toxocara species larval antigens in tissue was studied by immunohis tochemical techniques in five human cases of toxocariasis. Patients had a clinical his tory suggestive of the infection, a positive enzyme-linked immunosorbent assay test for toxocaral antibodies, and histopathologic patterns of toxocariasis. Liver biopsies were taken from all five patients, usually under suspicion of liver abscess or of meta static or primary liver neoplasia. In one case a segment of the right colon adjacent to the liver lesions was also examined. Immunohistochemical techniques using polyclonal antiserum raised in rabbits against excretory secretory (TES) antigens of Toxocara canis larvae detected antigen deposits phagocyte ed by macrophages at the periphery of eosinophil-rich granulomas, in the portal inflammatory infiltrate, between epithelioid cells close to the areas of necrosis, and sequestered in the collagen of the periportal region. Both nonabsorbed and Strongyloides venezuelensis and Ascaris suum absorbed sera essentially detected similar antigenic sites, but these sites were more frequently observed and more evident when the former was used. The importance of antigen detection for the etiologic diagnosis of eosinophilic granulomatous inflammation and eosinophil-rich inflammatory infiltrates is stressed. Int J Surg Pathol 2(2):117-124, 1994
Polypoid Histiocytoma (Fibroxanthoma) of the Stomach Mimicking Signet Ring Adenocarcinoma by Endoscopic Evaluation
Authors: Costa Michael J. , Larkin Edward , Ruebner Boris H.
Published: November 2007

A 3 cm polyp of the gastric greater curvature formed by a histiocytoma (fibroxanthoma) was discovered in a 62-year-old, diabetic, chronically-ill woman undergoing evalua tion for anemia. The histology of the endoscopic biopsy of this lesion mimicked a signet ring adenocarcinoma as the mucosa was infiltrated by histiocytic cells with enlarged, atypical nuclei and intracytoplasmic mucin. The patient died without clinical evidence of recurrence from staphylococcal septicemia 8 months following subtotal proximal gastrectomy. While the pathologic findings fell into the spectrum of an in flammatory fibroid polyp or histiocytoma (inflammatory pseudotumor, plasma cell granuloma) of the stomach, the predominance of foamy histiocytes was distinctive. In addition, histiocytic cells were present in the enlarged perigastric lymph nodes, the spleen, and the bone marrow. The histogenesis of this gastric polyp is obscure and not the focus of this report. This polyp mimicked an adenocarcinoma by endoscopic evaluation both by its exophytic appearance and microscopic histology. Immunohisto chemistry for markers of epithelial and histiocytic differentiation may be used to avoid this diagnostic trap and establish the diagnosis prior to surgery. Int J Surg Pathol 2(2): 141-145, 1994
Long-term Treatment With Pravastatin Alone and in Combination With Gemfibrozil in Familial Type IIB Hyperlipoproteinemia or Combined Hyperlipidemia
Authors: Napoli Claudio , Lepore Stefano , Chiariello Paola , Condorelli Mario , Chiariello Massimo
Published: November 2007

Background: Pravastatin inhibits 3-hydroxy-3-methylglutaryl-coenzyme A reductase. It pre vents mevalonate synthesis, reducing endogenous cholesterol production, and reduces cholesterol content in the liver, thus resulting in a down-regulation of low-density lipoprotein receptor production. Gemfibrozil reduces very low-density lipoprotein production and low- density lipoprotein-cholesterol level and increases very low-density lipoprotein catabolism. Therefore, it was suggested that combination therapy with both drugs could effect greater reduction of cholesterol levels as compared to pravastatin alone. The present study was car ried out to evaluate the efficacy and safety of pravastatin as a monotherapy or in combination with gemfibrozil in the treatment of patients with familial type IIb hyperlipoproteinemia or familial combined hyperlipidemia.

Methods and Results: Forty-one patients were included in the study. All patients initially followed 6 weeks of hypolipidemic diet; subsequently they were randomized and received either 20 mg once daily of pravastatin alone (n = 13) or 20 mg of pravastatin together with 600 mg of gemfibrozil twice daily (n = 14). As a control, 14 patients were treated with diet only. The treatment lasted 24 months and clinical evaluation and laboratory tests were done at given time points. Both groups of treated patients showed an early reduction (3 months) of total (about 30% P < .0 vs controls), low-density lipoprotein (about 35%, P < .0 vs con trols) and very low-density lipoprotein cholesterol levels (about 18%, P = NS). In contrast, high-density lipoprotein cholesterol levels increased significantly in patients treated with pravastatin and gemfibrozil (about 20%, P < .05 vs controls). Pravastatin treatment alone reduced the level of serum triglycerides as efficiently as in combination with gemfibrozil. Data showed a sustained normalization of lipid profile until 24 months. However, this effect was achieved in patients that had rather low levels of triglycerides. During the treatment we did not observe any difference in the incidence of possible drug-related side effects. Severe myopathy or rhabdomyolysis was not observed at the doses of the drugs used in our study. Conclusions: Therapy with pravastatin alone and in combination with gemfibrozil resulted in significant and sustained normalization of lipid profile in high-risk patients with familial type lib hyperlipoproteinemia or familial combined hyperlipidemia.