bluuebunny/crossref_metadata_2025 huggingface dataset:
Late Quaternary History of Tundra Vegetation in Northwestern Alaska
Authors: Anderson Patricia M. , Bartlein Patrick J. , Brubaker Linda B.
Published: October 2002

Pollen analysis of a new core from Joe Lake indicates that the late Quaternary vegetation of northwestern Alaska was characterized by four tundra and two forest-tundra types. These vegetation types were differentiated by combining quantitative comparisons of fossil and modern pollen assemblages with traditional, qualitative approaches for inferring past vegetation, such as the use of indicator species. Although imprecisely dated, the core probably spans at least the past 40,000 yr. A graminoid-Salixtundra dominated during the later and early portions of the glacial record. The middle glacial interval and the transition from glacial to interglacial conditions are characterized by a graminoid-Betula-Salixtundra. APopulusforest-Betulashrub tundra existed during the middle potion of this transition, being replaced in the early Holocene by aBetula-Alnusshrub tundra. The modernPiceaforest-shrub tundra was established by the middle Holocene. These results suggest that the composition of modem tundra communities in northwestern Alaska developed relatively recently and that throughout much of the late Quaternary, tundra communities were unlike the predominant types found today in northern North America. Although descriptions of vegetation variations within the tundra will always be restricted by the innate taxonomic limitations of their herb-dominated pollen spectra, the application of multiple interpretive approaches improves the ability to reconstruct the historical development of this vegetation type.
Holocene Paleoenvironmental Change in the Kenyan Central Rift as Indicated by Micromammals from Enkapune Ya Muto Rockshelter
Authors: Marean Curtis W. , Mudida Nina , Reed Kaye E.
Published: October 2002

An assemblage of micromammals, recovered from the Holocene levels of a rockshelter at 2400 m in the montane forest of the Mau Escarpment, were examined with the goal of testing and contributing to prior reconstructions of paleoenvironments in the Central Rift Valley of Kenya. Species representation in the assemblage is consistent with a drying of the Rift Valley lakes in the middle Holocene and suggests a decrease in forest accompanied by expanding grasslands near the site. Changes in the abundance of grassland species suggests an increase in the frequency of fires, probably the result of pastoral burning. The body size of the root rat (Tachyoryctes splendens) decreases from the early Holocene to the middle Holocene, and this may indicate increasing aridity or increasing temperature. We compare measures of species diversity (number of taxa, species richness, and the Shannon diversity index) for both micromammals and macromammals since species diversity may change with paleoenvironmental change. The macromammals show no changes in species diversity that are assignable to paleoenvironmental change, while the micromammals show a trend toward decreasing diversity from the early to middle Holocene, and then show an increase in diversity during the peak of the middle Holocene dry phase, though sample size effects may be confounding the patterning.
Mid-Holocene Erosion of Soil Catenas on Moraines near the Type Pinedale Till, Wind River Range, Wyoming
Authors: Dahms Dennis E.
Published: October 2002

Buried soils are described from the floors of four kettles on Pinedale piedmont moraines of the southwestern Wind River Range, Wyoming, near the type locality of the Pinedale Till. The buried soils indicate that a previously unreported episode of slope erosion has occurred along adjacent catenas on some of the moraines in this region. Radiocarbon ages of the buried soils indicate that slope erosion occurred during the middle Holocene from 8540 ± 190 to 4800 ± 60 14C yr B.P. The presence of buried soils in moraine kettles indicates that profiles on the crests and backslopes of some of the moraines in this region are not the products of continuous post-Pinedale soil formation. Rather, the crest and backslope soils on Pinedale moraines result from two periods of soil development separated by an interval of erosion. Thus, soils on crests and backslopes are considered to be welded profiles. Relative-age studies that use soil data to estimate the age of moraines in this region must take into account the possibility that a mid-Holocene erosion episode affected the genesis and morphology of soils on the moraines. This study corroborates results of previous work that suggests that data from complete catenas are more useful for estimating the characteristic soil development on Quaternary moraines than are data derived from crests alone.
The Response of Northern Hemisphere Extratropical Climate and Vegetation to Orbitally Induced Changes in Insolation during the Last Interglaciation
Authors: Harrison Sandy P. , Kutzbach John E. , Prentice I. Colin , Behling Pat J. , Sykes Martin T.
Published: October 2002

The last interglaciation (substage 5e) provides an opportunity to examine the effects of extreme orbital changes on regional climates. We have made two atmospheric general circulation model experiments: P+T+ approximated the northern hemisphere seasonality maximum near the beginning of 5e; P-T- approximated the minimum near the end of 5e. Simulated regional climate changes have been translated into biome changes using a physiologically based model of global vegetation types. Major climatic and vegetational changes were simulated for the northern hemisphere extratropics, due to radiational effects that were both amplified and modified by atmospheric circulation changes and sea-ice feedback. P+T+ showed mid-continental summers up to 8°C warmer than present. Mid-latitude winters were 2-4°C cooler than present but in the Arctic, summer warmth reduced sea-ice extent and thickness, producing winters 2-8°C warmer than present. The tundra and taiga biomes were displaced poleward, while warm-summer steppes expanded in the mid latitudes due to drought. P-T- showed summers up to 5°C cooler than present, especially in mid latitudes. Sea ice and snowpack were thicker and lasted longer; polar desert, tundra, and taiga biomes were displaced equatorward, while cool-summer steppes and semideserts expanded due to the cooling. A slight winter warming in mid latitudes, however, caused warm-temperate evergreen forests and scrub to expand poleward. Such qualitative contrasts in the direction of climate and vegetation change during 5e should be identifiable in the paleorecord.
Ice-Volume Forcing of East Asian Winter Monsoon Variations in the Past 800,000 Years
Authors: Ding Zhongli , Liu Tungsheng , Rutter Nat W. , Yu Zhiwei , Guo Zhengtang , Zhu Rixiang
Published: October 2002

Particle-size measurements of some typical loess-soil samples taken in different localities of the Chinese Loess Plateau demonstrate that the grain size ratio of <2 μm/>10 μm (%) can be used as an indicator of variations in intensity of the East Asian winter monsoon winds. Grain-size curves of the Baoji and Weinan sections show that this proxy indicator is very sensitive to loess-soil alterations. Analytical results also suggest that during soil-forming periods, eolian dust accumulation was still substantial and, hence, loess deposition can be regarded as a nearly continuous process during the Quaternary period. In this study we compared the Baoji grain-size time series with the SPECMAP marine isotope record with the objective of elucidating the dynamic linkage between changes in global ice volume and the winter monsoon circulation. Both records show good agreement at both time and frequency domains. In particular, the winter monsoon variations are also dominated by a 100,000 yr period over the past 800,000 yr. It is thus inferred that direct local insolation forcing could be less important in driving the East Asian winter monsoon variability, and, alternatively, variations in glacial-age boundary conditions may have played a key role in modulating and pacing its strength and timing.
Holocene Climate Effects on the Development of a Peatland on the Tuktoyaktuk Peninsula, Northwest Territories
Authors: Vardy Sheila R. , Warner Barry G. , Aravena Ramon
Published: October 2002

Six cores were collected from a small peatland on the Tuktoyaktuk Peninsula, yielding up to 1.8 m of organic material and 1.2 m of ice-rich material. Stratigraphic relationships, radiocarbon dating, and pollen, plant macrofossil, and isotopic analyses are used to reconstruct the developmental history of the peatland. Organic matter began to accumulate in the basin about 7200 yr B.P., during a period when the climate is thought to have been warmer than present. Initially the permafrost table was probably below the bottom of the basin, and an open-water mineral wetland with emergent and submergent aquatic vegetation occupied the site. Enriched δ18O values from ice samples confirm the existence of an open water body with a water balance strongly affected by evaporation. Transformation to a graminoid fen peatland was underway by 6300 yr B.P. Permafrost and ice began to form in the peatland at this time. Low-centered polygons probably began to develop by 4700 yr B.P. and subsequently evolved into the high-centered polygons which characterise the southwestern part of the peatland today. Peat accumulation in the polygons has been extremely slow for the last 4000 years. The eastern, wetter part of the basin has largely remained unchanged since its inception about 7000 yr B.P. Development of the peatland may be linked to permafrost formation that was controlled by regional climate changes during the Holocene.
Geochronology of Middle and Upper Pleistocene Loess Sections in Hungary
Authors: Frechen Manfred , Horváth Erzsébet , Gábris Gyula
Published: October 2002

The application of both thermoluminescence and infrared stimulated luminescence dating to the extensively studied “classical” Hungarian loess/paleosol sequences from Basaharc, Mende, and Paks provides a reliable chronological framework and climatostratigraphic reconstruction for the last interglacial/glacial cycle. Based on this combined luminescence dating study a new chronology is proposed for the “Young Loess” in Hungary. Luminescence dating suggests that the loess below the MF2 horizon formed during the penultimate glaciation. The MF1 horizon probably formed during an interstade within oxygen isotope stage 3. For the youngest loess, overlying MF1, a very high accumulation rate was determined. Large time gaps occur above MF2 and MF1, indicating that most of the record of the last glaciation is missing in the standard sections at Basaharc, Mende, and Paks. Either large discontinuities or a very low accumulation rate occurred in all three type sections during the soil-forming periods. High-resolution studies of climatic proxies using this combined luminescence dating approach provide a reliable chronological framework for loess and loess derivatives of the last glacial cycle in Hungary, although a precise and complete chronostratigraphic reconstruction cannot be achieved from the incomplete records found at these sites.
Numerical Ages of Holocene Tributary Debris Fans Inferred from Dissolution Pitting on Carbonate Boulders in the Grand Canyon of Arizona
Authors: Hereford Richard , Thompson Kathryn S. , Burke Kelly J.
Published: October 2002

Carbonate boulders transported down steep tributary channels by debris flow came to rest on Holocene debris fans beside the Colorado River in Grand Canyon National Park. Weakly acidic rainfall and the metabolic activity of blue-green algae have produced roughly hemispheric dissolution pits as much as 2-cm deep on the initially smooth surfaces of the boulders. The average depth of dissolution pits increases with relative age of fan surfaces. The deepening rate averages 2.4 mm/1000 yr (standard error = 0.2 mm/1000 yr), as calculated from several radiometrically dated surfaces and an archeological structure. This linear rate, which appears constant over at least the past 3000 yr, is consistent with field relations limiting the maximum age of the fans and with the physical chemistry of limestone dissolution. Dissolution-pit measurements (n= 6973) were made on 617 boulders on 71 fan surfaces at the 26 largest debris fans in Grand Canyon. Among these fan surfaces, the average pit depth ranges from 1.2 to 17.4 mm, and the resulting pit dissolution ages range from 500 to 7300 cal yr B.P. Most (75%) surfaces are younger than 3000 yr, probably because of removal of older debris fans by the Colorado River. Many of the ages are close to 800, 1600, 2300, 3100, or 4300 cal yr B.P. If not the result of differential preservation of fan surfaces, this clustering implies periods of heightened debris-flow activity and increased precipitation.
A 5000-yr Record of Climate Change in Varved Sediments from the Oxygen Minimum Zone off Pakistan, Northeastern Arabian Sea
Authors: von Rad Ulrich , Schaaf Michael , Michels Klaus H. , Schulz Hartmut , Berger Wolfgang H. , Sirocko Frank
Published: October 2002

The upper Holocene marine section from a kasten core taken from the oxygen minimum zone off Karachi (Pakistan) at water depth 700 m contains continuously laminated sediments with a sedimentation rate of 1.2 mm/yr and a unique record of monsoonal climatic variability covering the past 5000 years. Our chronostratigraphy is based on varve counts verified by conventional and AMS14C dating. Individual hemipelagic varve couplets are about 0.8–1.5 mm thick, with light-colored terrigenous laminae (A) deposited mainly during the winter monsoon alternating with dark-colored laminae (B) rich in marine organic matter, coccoliths, and fish debris that reflect deposition during the high-productivity season of the late summer monsoon (August–October). Precipitation and river runoff appear to control varve thickness and turbidite frequency. We infer that precipitation decreased in the river watershed (indicated by thinning varves) after 3500–4000 yr B.P. This is about the time of increasing aridification in the Near East and Middle East, as documented by decreasing Nile River runoff data and lake-level lowstands between Turkey and northwestern India. This precipitation pattern continued until today with precipitation minima about 2200–1900 yr B.P., 1000 yr B.P., and in the late Middle Ages (700–400 yr B.P.), and precipitation maxima in the intervening periods. As documented by spectral analysis, the thickness of varve couplets responds to the average length of a 250-yr cycle, a 125-yr cycle, the Gleissberg cycle of solar activity (95 yr), and a 56-yr cycle of unknown origin. Higher frequency cycles are also present at 45, 39, 29–31, and 14 yr. The sedimentary gray-value also shows strong variability in the 55-yr band plus a 31-yr cycle. Because high-frequency cyclicity in the ENSO band (ca. 3.5 and 5 yr) is only weakly expressed, our data do not support a straightforward interaction of the Pacific ENSO with the monsoon-driven climate system of the Arabian Sea.
First Quaternary Fossil Record of Caecilians from a Mexican Archaeological Site
Authors: Wake Thomas A. , Wake Marvalee H. , Lesure Richard G.
Published: October 2002

A single vertebra from an Early Formative period archaeological site in coastal Chiapas, México, is identified as belonging to the amphibianDermophis mexicanus(Duméril and Bibron) 1841 (Amphibia: Gymnophiona: Caeciliidae). The vertebra was recovered from deposits dated to approximately 1200–1350 B.C. The specimen represents the first Quaternary fossil record for gymnophiones. Its presence suggests the possible role of the species as a bioturbator. Its recovery is further evidence of the utility of fine-grained archaeological recovery techniques.
Male gender: Risk factor for severe symptomatic cholelithiasis
Authors: Lein Heng‐Hui , Huang Ching‐Shui
Published: October 2002

The aim of this study was to determine the effect of male gender on the clinical presentation of symptomatic cholelithiasis. Laparoscopic cholecystectomy (LC) has been accepted as standard procedure for the management of symptomatic cholelithiasis even when the gallbladder is acutely inflamed. With the accumulated experience in the management of acute cholecystitis, some factors including male gender were recognized to influence the clinical presentation of symptomatic cholelithiasis and increase the conversion rate during LC. This retrospective study tried to clarify the correlation between male gender and the clinical presentation of symptomatic cholelithiasis. The medical records of all patients presenting with symptomatic cholelithiasis from January 1994 to August 1999 were evaluated. These cases were divided into four groups as follows: (1) elective LC group: patients with a history of biliary colic or acute attack of cholecystitis but whose LC was performed electively without any inflammatory change in the gallbladder during operation; (2) acute LC group: patients presenting with acute cholecystitis, and LC was performed successfully without conversion; (3) acute conversion group: patients who underwent LC during the course of acute cholecystitis but the procedure were disturbed by severe inflammatory change so they were converted to open surgery; (4) acute open group: patients whose acute cholecystitis was managed by direct open surgery due to the preoperative prediction that LC would not succeed. The correlation of gender, age, and operating time were assessed among these four groups. We found that: (1) the male/female ratio increased (in the patient group sequence of simple LC, acute LC, acute open, and acute conversion group); (2) in the acute LC group male patients had significantly (p=0.04, t‐test) longer operating time than females; (3) although there was no significant difference between the mean age of male (55.7±13.4) and female (56.3±15.7) patients in the acute cholecystitis groups (i.e., all patients in the acute LC, acute conversion, and acute open groups), the distribution curve by age in male patients showed a significantly shift to a younger age compared with female patients (p=0.009, Fisher’s exact test).
Histologic Features of the Liver in Type Ia Glycogen Storage Disease: Comparative Study between Different Age Groups and Consecutive Biopsies
Authors: Göğüş Safiye , Koçak Nurten , Ciliv Gönenç , Karabulut Erdem , Akçören Zuhal , Kale Gülsev , Çağlar Melda
Published: October 2002

In this report, the histologic criteria for the diagnosis of type Ia glycogen storage disease (GSD) in a wide age range were studied. Liver needle biopsies of 44 patients with type Ia GSD confirmed by enzyme analysis were re-evaluated and compared. Fatty change, nuclear hyperglycogenation (NH), and fibrosis were examined and graded. The second biopsies of 14 patients were also evaluated and compared with the first ones. The patients were grouped according to age: group I: <1 year (18 cases), group II: 1–5 years (19 cases), group III: >5 years (7 cases). A mosaic pattern was detected in all biopsies. The amount of fibrosis in group I was less than that in the other two groups. The fatty change in group I was more prominent. There was not much difference in the amount of NH between age groups. In comparing the two different biopsies of 14 patients, the amount of fibrosis was found to be increased in 7 cases. NH was also increased in a different group of 7 patients. These findings were both statistically significant. The amount of fatty change was minimal in most of the cases. Fibrosis is associated with types III, IV, VI, IX, and X GSD. Our results support previous studies stating that fibrosis may also be present and varies in extent in type I GSD. Fatty change as large lipid vacuoles and NH may not be seen in many cases of type I GSD. Therefore, histologic criteria for the diagnosis of GSD may not be specific, and enzyme analysis should be performed.
Rapid Onset of Severe Twin–Twin Transfusion Syndrome Caused by Placental Venous Thrombosis
Authors: Nikkels Peter G.J. , van Gemert Martin J.C. , Sollie-Szarynska Krystyna M. , Molendijk Harry , Timmer Bert , Machin Geoffrey A.
Published: October 2002

We report a case of rapid onset of severe twin–twin transfusion syndrome (TTTS) at 25 weeks gestation in a monochorionic twin pregnancy that was uneventful before that time. Thrombosis of a main venous branch draining several arteriovenous (AV) anastomoses to the donor changed the previous hemodynamic balance that existed between multiple bidirectional AV anastomoses. The opposing AVs became hemodynamically uncompensated and, despite amnioreductions, severe TTTS developed. At 27 weeks a cesarean section was performed because of worsening cardiotocography parameters of both fetuses. Birth weights were 750 and 1840 g, and initial hemoglobin concentrations were 9.2 and 13.4 mmol/liter for donor and recipient, respectively. The recipient twin died 5 months later of an ischemic, necrotic, and perforated small intestine due to a throm-bosed superior mesenteric artery. The donor is well at 2.5 years. No abnormalities in several factors associated with thrombophilia, including factor V Leiden mutations, were found in the parents.
What memory strategy is best for examinations in psychology?
Authors: McDougall Siné , Gruneberg Michael
Published: October 2002

This study examines the memory strategies used by psychology students during their finals examinations. The strategies used, as evidenced by exam plans at the front of their answers, were related to actual examination performance. The results of the present study showed that, when students' worst marks were considered, those not showing evidence of having used any strategy performed significantly worse than those using a strategy. The strategy which involved listing researchers names proved to be better than a no‐strategy approach. However, when students' best marks were considered, no differences were apparent in examination marks as a result of the strategies which students employed. This suggests that the type of strategy used is more important when students' knowledge of a topic is weak in comparison to when students have a good knowledge of a topic area. Copyright © 2002 John Wiley & Sons, Ltd.
Automatic EEG interpretation adaptable to individual electroencephalographer using artificial neural network
Authors: Nakamura Masatoshi , Sugi Takenao , Ikeda Akio , Shibasaki Hiroshi
Published: October 2002

In view of the fact that the visual EEG interpretation could be a subjective task and may vary among the electroencephalographers, the main objective of this study was to develop an automatic EEG interpretation system which is adaptable to each electroencephalographer. The system adapted to each electroencephalographer would bring a close automatic EEG interpretation to that done by the electroencephalographer's visual interpretation. The adaptable automatic EEG interpretation was accomplished by using the constructive neural network with forgetting factor. The artificial neural network was constructed so as to give the integrative interpretation of the EEG based on the intermediate judgment of 13 items that characterized the visual interpretation. The developed method was evaluated based on the visually inspected EEG data of 37 patients by electroencephalographer‐A and the data of 20 patients by electroencephalographer‐B. The adapted ANN showed good agreement with each electroencephalographer's visual inspection. The proposed automatic EEG interpretation by use of the ANN can be a powerful assistant tool for individual electroencephalographers for their EEG interpretation. Copyright © 2001 John Wiley & Sons, Ltd.
Computationally efficient algorithms for state estimation with ellipsoidal approximations
Authors: Maksarov D. G. , Norton J. P.
Published: October 2002

Computationally efficient algorithms for computing minimal‐volume ellipsoidal bounds on the state of a linear, discrete‐time dynamical system are presented. Ellipsoidally bounded noise is considered, rather than the scalar‐noise case usually treated; the latter is covered as a degenerate special case of the former. The algorithms have differing accuracy and computational requirements, resulting from differing specifications of the bounds. The paper compares these alternative approaches to computing ellipsoidal bounds on state, giving simulation results to illustrate the performance of the algorithms. Copyright © 2002 John Wiley & Sons, Ltd.
A test of homogeneity for autoregressive processes
Authors: Gómez Rafael Martínez Pedro , Drouiche Karim
Published: October 2002

In this paper, we introduce a new hypothesis test to determine whether or not two spectral densities are proportional. We deliberately limit our study to autoregressive processes and derive the asymptotic behaviour of the test. A test for autoregressive coefficient nullity or randomness is deduced. We derive asymptotic behaviour for these tests and show the usefulness of our test to detect speech in a noisy environment. Copyright © 2002 John Wiley & Sons, Ltd.
An efficient adaptive algorithm for edge detection based on the likelihood ratio test
Authors: De Santis A. , Iacoviello D.
Published: October 2002

The edge detection problem in blurred and noisy 2‐D signals is dealt with. An adaptive signal processing algorithm is proposed which marks edge points according to an hypothesis test which compares the likelihoods of two models describing the local signal behaviour in the two cases of absence/presence of an edge. The two models are identified by a regularized least squares estimation algorithm, obtaining a numerically efficient procedure, quite robust with respect to additive noise and blurr perturbation. No global thresholding or data prefiltering is required. Copyright © 2002 John Wiley & Sons, Ltd.
On‐line almost‐sure parameter estimation for partially observed discrete‐time linear systems with known noise characteristics
Authors: Elliott Robert J. , Ford Jason J. , Moore John B.
Published: October 2002

In this paper we discuss parameter estimators for fully and partially observed discrete‐time linear stochastic systems (in state‐space form) with known noise characteristics. We propose finite‐dimensional parameter estimators that are based on estimates of summed functions of the state, rather than of the states themselves. We limit our investigation to estimation of the state transition matrix and the observation matrix. We establish almost‐sure convergence results for our proposed parameter estimators using standard martingale convergence results, the Kronecker lemma and an ordinary differential equation approach. We also provide simulation studies which illustrate the performance of these estimators. Copyright © 2002 John Wiley & Sons, Ltd.
Effects of state regulations on marketing margins and price transmission asymmetry: Evidence from the New York City and upstate New York fluid milk markets
Authors: Romain Robert , Doyon Maurice , Frigon Mathieu
Published: October 2002

A marketing margin model that allows testing for constant returns to scale technology and asymmetric marketing costs and farm price transmissions is proposed. Results indicate that a constant returns to scale technology cannot be rejected. During the period prior to the enactment of the price gouging law in June 1991 by the New York State Legislature, significant short‐run and long‐run asymmetries in both marketing costs and farm price transmissions were identified. After 1991, these asymmetries were no longer significant or were reduced substantially. Finally, the legislative change that occurred in 1987, allowing Farmland Dairies' entry into the New York City fluid milk market, contributed significantly to reducing marketing margins in the New York City fluid milk market. [EconLit Citations: D400, C300] © 2002 Wiley Periodicals, Inc.
HOXD13 polyalanine tract expansion in classical synpolydactyly type Vordingborg
Authors: Kjaer Klaus Wilbrandt , Hedeboe Jess , Bugge Merete , Hansen Claus , Friis‐Henriksen Karen , Vestergaard Maria Baeksted , Tommerup Niels , Opitz John M.
Published: October 2002

In 1927, Oluf Thomsen, in a classic paper, described a seven‐generation family with autosomal dominant axial synpolydactyly (SPD)—the Vordingborgtyp of axis duplication and dysostosis. Expansion of a polyalanine tract in the HOXD13 gene is known to cause synpolydactyly. We have rediscovered part of the family described by Thomsen, and detected a 9 triplet polyalanine expansion within HOXD13segregating with the disorder. The phenotypic spectrum in mutation carriers ranged from severe to inapparent bone malformations. In the latter case, only dermatoglyphics revealed the genetic status. © 2002 Wiley‐Liss, Inc.
Trisomy 20q caused by der(4) t(4;20) (q35;q13.1): Report of a new patient and review of the literature
Authors: Plotner Pamela L. , Smith Janice L. , Northrup Hope
Published: October 2002

An infant with multiple congenital anomalies and severe developmental delay was found to have a derivative chromosome 4 by routine karyotypic analysis. Using telomeric FISH analysis, the source of the additional chromatin was determined to be from 20q. The infant, thus, is trisomic for 20q13.1 to 20qter and monosomic for the sub‐telomeric region of 4q. Other cases of trisomy 20q13.1to 20qter associated with telomeric deletions are reviewed and compared to the current patient. © 2002 Wiley‐Liss, Inc.
Probable identity of Goltz syndrome and Van Allen‐Myhre syndrome: Evidence from phenotypic evolution
Authors: Hancock Susan , Pryde Peter , Fong Christine , Brazy Jane E. , Stewart Katharina , Favour Amy , Pauli Richard M.
Published: October 2002

We describe a girl who was diagnosed with split foot‐split hand anomaly prenatally, in whom at birth the diagnosis of Van Allen‐Myhre syndrome was made, and who at 8 months of age was recognized to have Goltz syndrome. Based on the evolution of clinical features in this infant, we suggest that our case, as well as that reported by Van Allen and Myhre, is an example of unusually severe Goltz syndrome. © 2002 Wiley‐Liss, Inc.
Personal experiences of cystic fibrosis (CF) carrier couples prospectively identified in CF families
Authors: Henneman Lidewij , Kooij Loes , Bouman Katelijne , Kate Leo P. ten
Published: October 2002

This qualitative study explores the experiences of cystic fibrosis (CF) carrier couples, prospectively identified in CF families, and the impact of the resulting genetic risk on reproductive behavior. Of the 12 couples identified until 1997, seven couples participated in semistructured interviews and two couples filled in a questionnaire, two to eight years after receipt of the test‐results. After receiving the results, most couples reported that they were shocked, because they did not expect to both be carriers. More anxiety was expressed by those who were pregnant (n = 4) at the time of testing. There were reported difficulties in disclosing the results to family members, and the reactions of family members were not always supportive. After testing, some couples had problems with reproductive decision‐making. All viable pregnancies (17 in 8 couples) were monitored by prenatal diagnosis; all affected pregnancies were terminated (6 in 4 couples). Couples who have live‐born children after testing may subsequently have concerns during infancy about the correctness of the results of prenatal diagnosis and how to inform their children. Most couples did not regret the testing and, in general, the counseling was experienced positively, although some dissatisfaction was reported with regard to the psychological support received during pregnancy. Couples supported the idea of carrier screening in the general population, although various concerns were expressed. The results indicate a preference for testing before pregnancy. These findings may be useful in investigating possible dilemmas caused by the introduction of population carrier screening. Observations reported here might also apply to other recessively inherited disorders. © 2002 Wiley‐Liss, Inc.
Investigation of Notch3 as a candidate gene for bipolar disorder using brain hyperintensities as an endophenotype
Authors: Ahearn Eileen P. , Speer Marcy C. , Chen Y.T. , Steffens David C. , Cassidy Frederick , Van Meter Susan , Provenzale James M. , Weisler Richard H. , Rama Krishnan K. Ranga
Published: October 2002

The purpose of the study was to consider MRI hyperintensities as a potential endophenotype for bipolar disorder (BPD) and to investigate Notch3 (CADASIL) as a candidate gene for BPD. MRI scans were performed on 21 members of a family with a high incidence of BPD. Two‐point and multipoint linkage analyses were performed and two exons of Notch3 were investigated with SSCP. Fifteen of 21 family members had MRI hyperintensities, including all bipolar patients and six family members with no affective illness. Two‐point linkage analysis yielded negative results for all models. Multipoint linkage analysis yielded negative results except for Model 1a, in which a maximal LOD score was −1.24. A mutation screen of Exons 3 and 4 was negative. Notch3 does not appear to be a candidate gene for BPD in this family. © 2002 Wiley‐Liss, Inc.
Genitopatellar syndrome: Delineating the anomalies of female genitalia
Authors: Lammer Edward J. , Abrams Liane
Published: October 2002

We report the second female with genitopatellar syndrome, a recently identified arthrogryposis syndrome. The salient features include severe mental retardation and microcephaly with absence of the corpus callosum, absent/hypoplastic patellae, genital anomalies, and hydronephrosis. © 2002 Wiley‐Liss, Inc.
Infantile hypotonia as a presentation of rett syndrome
Authors: Heilstedt Heidi A. , Shahbazian Mona D. , Lee Brendan
Published: October 2002

Rett syndrome (RTT) is classically defined by meeting certain clinical diagnostic criteria. It affects mostly females, and one possible pathogenic mechanism was considered to involve mitochondrial function. This was based on the finding of ultrastructural alterations in the mitochondria and decreased respiratory chain enzyme activity. However, the principal etiology of RTT has since been found to be mutations in the MECP2 gene, which is located on the X chromosome. Molecular analysis has allowed the phenotype of MECP2 mutations to be broadened beyond RTT to include girls who have mild mental retardation, autism, and an Angelman syndrome phenotype, as well as males with severe encephalopathy. We present a girl with a previously described mutation in the MECP2 gene whose phenotype is of atypical RTT. She presented with hypotonia and developmental delay in infancy without a clear period of normal development. As part of her evaluation for hypotonia, a muscle biopsy and respiratory chain enzyme analysis showed a slight decrease in respiratory chain enzyme activity consistent with previous reports. This report supports broadening the phenotype of patients who should be considered for MECP2 mutation analysis to include cases of developmental delay and hypotonia without evidence of an initial period of normal development. Furthermore, it supports the hypothesis of an underlying secondary defect in energy metabolism contributing to the pathogenesis of RTT. © 2002 Wiley‐Liss, Inc.
Excretion and measurement of estradiol and progesterone metabolites in the feces and urine of female squirrel monkeys (Saimiri sciureus)
Authors: Moorman E.A. , Mendoza S.P. , Shideler S.E. , Lasley B.L.
Published: October 2002

The first objective of the present study was to determine the metabolic form and rate of excretion of ovarian hormone metabolites in the urine and feces of female squirrel monkeys injected with radiolabeled progesterone (Po) and estradiol. The major portion of the urinary metabolites of both hormones was excreted within 16–24 hr post‐injection. Estrogen and Po isotopes in feces exhibited an excretion peak at 16 hr post‐injection. The majority of recovered radiolabel of both hormones was excreted in feces. Chromatographic separation of fecal extractions indicated that the major estrogen metabolites in feces are in the free as opposed to the conjugated form. The radioactivity and immunoreactivity for estrone and estradiol (E1 and E2, respectively) in eluates of fecal samples subjected to celite co‐chromatography indicated that both free E1 and E2 exist as excretion products in the feces of female squirrel monkeys. The major radioactive peaks for Po metabolites showed peaks in the elution profile at or very near the Po standard, and corresponded with the celite co‐chromatography elution profile of Po standard when subjected to enzyme immunoassay (EIA). The second objective was to validate the application of EIA systems to measure fecal metabolites. Reproductive events of one female squirrel monkey across one annual reproductive cycle are described using the endocrine profile generated from fecal steroid assays. Examination of this profile confirmed that longitudinal fecal sampling and steroid hormone metabolite measurement in feces was not only feasible and practical, but accurately detected known reproductive events as well. © 2002 Wiley‐Liss, Inc.
Brief communication: Arboreal bipedalism in Bwindi chimpanzees
Authors: Stanford Craig B.
Published: October 2002

Evidence of the form and function of bipedal behavior in nonhuman primates provides critical evidence to test theories about the origins of hominid bipedalism. Bipedalism has long been considered an evolutionarily interesting but rare behavior in wild chimpanzees. During May 2001, chimpanzees of the Ruhija community in the Bwindi Impenetrable National Park, Uganda, engaged in an exceptional frequency of arboreal bipedalism when feeding in large Ficus trees. Seventy‐eight bipedal bouts of at least 5 sec duration were recorded for the entire community (0.49 bouts/hr), with a mean duration of 13.7 sec (±1.6 sec). The animals employed many variations on the bipedal postural theme, ranging from erect standing on the largest substrates while grasping overhead limbs for support, to standing on one leg while suspending the other leg in space, to extended‐lean standing, in which bipedal standing transitioned into horizontal arm‐leg suspension as the animal reached for more distant fruits. Bipedalism was used as part of a behavioral repertoire that integrated brachiation, four‐limbed suspension, and forelimb‐supported standing for effective small‐fruit foraging. These observations suggest that under certain ecological conditions, arboreal bipedalism can be an important posture for wild chimpanzees, and may have been an important behavioral precursor to full terrestrial bipedalism. Am J Phys Anthropol 119:87–91, 2002. © 2002 Wiley‐Liss, Inc.
Succinate in dystrophic white matter: A proton magnetic resonance spectroscopy finding characteristic for complex II deficiency
Authors: Brockmann Knut , Bjornstad Alf , Dechent Peter , Korenke Christoph G. , Smeitink Jan , Trijbels J. M. Frans , Athanassopoulos Sabine , Villagran Rafael , Skjeldal Ola H. , Wilichowski Ekkehard , Frahm Jens , Hanefeld Folker
Published: October 2002

A deficiency of succinate dehydrogenase is a rare cause of mitochondrial encephalomyopathy. Three patients, 2 sisters and 1 boy from an unrelated family, presented with symptoms and magnetic resonance imaging signs of leukoencephalopathy. Localized proton magnetic resonance spectroscopy indicated a prominent singlet at 2.40ppm in cerebral and cerebellar white matter not present in gray matter or basal ganglia. The signal was also elevated in cerebrospinal fluid and could be identified as originating from the two equivalent methylene groups of succinate. Subsequently, an isolated deficiency of complex II (succinate:ubiquinone oxidoreductase) was demonstrated in 2 patients in muscle and fibroblasts. One of the sisters died at the age of 18 months. Postmortem examination showed the neuropathological characteristics of Leigh syndrome. Her younger sister, now 12 months old, is also severely affected; the boy, now 6 years old, follows a milder, fluctuating clinical course. Magnetic resonance spectroscopy provides a characteristic pattern in succinate dehydrogenase deficiency.
Neuroplasticity in old age: Sustained fivefold induction of hippocampal neurogenesis by long‐term environmental enrichment
Authors: Kempermann Gerd , Gast Daniela , Gage Fred H.
Published: October 2002

Neurons are continually born from endogenous stem cells and added to the dentate gyrus throughout life, but adult hippocampal neurogenesis declines precipitously with age. Short‐term exposure to an enriched environment leads to a striking increase in new neurons, along with a substantial improvement in behavioral performance. Could this plastic response be relevant for explaining the beneficial effects of leading “an active life” on brain function and pathology? Adult hippocampal neurogenesis in mice living in an enriched environment from the age of 10 to 20 months was fivefold higher than in controls. Relatively, the increase in neuronal phenotypes was entirely at the expense of newly generated astrocytes. This cellular plasticity occurred in the context of significant improvements of learning parameters, exploratory behavior, and locomotor activity. Enriched living mice also had a reduced lipofuscin load in the dentate gyrus, indicating decreased nonspecific age‐dependent degeneration. Therefore, in mice signs of neuronal aging can be diminished by a sustained active and challenging life, even if this stimulation started only at medium age. Activity exerts not only an acute but also a sustained effect on brain plasticity.
Full‐range kinetic study on bulk syndiotactic polymerization of styrene with homogeneous metallocene catalysis
Authors: Fan Rong , Li Bo‐Geng , Cao Kun , Zhou Wen‐Le , Shen Zhi‐Gang , Ye Meng
Published: October 2002

By choosing a proper agitator and reinforcing its stirring shear, powdery syndiotactic polystyrene (sPS) is prepared in a bulk precipitation process with two homogeneous metallocene catalyst systems [Cp*TiX3/MAO/TIBA (X = Cl or OPhOMe)]. A full‐range kinetics study of the heterogeneous polymerization is performed in detail to produce this kind of powdery sPS in an industrial process. A typical curve of conversion versus time takes an S shape and an obvious acceleration phenomenon occurs in the middle stage of the polymerization, although the polymer–monomer gel is avoided. The viscous‐average molecular weight of sPS goes through a peculiar increasing–decreasing–increasing change during the bulk polymerization process. These phenomena are viewed in terms of the two‐phase polymerization mechanism and the overheating in particles during polymerization. The influence of the metallocene catalyst type and concentration, MAO/Ti ratio, triisobutyl aluminum (TIBA)/Ti ratio, and polymerization temperature on the polymerization kinetics are investigated. TIBA has dual effects on the polymerization. A small amount of TIBA in the catalyst system promotes polymerization, but more TIBA leads to a low molecular weight sPS. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 2635–2643, 2002
In situ sol‐gel process of polystyrene/silica hybrid materials: Effect of silane‐coupling agents
Authors: Jang Jyongsik , Park Hwanseok
Published: October 2002

The polystyrene–silica hybrid materials have been successfully prepared from styrene and tetraethoxysilane in the presence of silane‐coupling agents by an in situ sol‐gel process. Triethoxysilyl group can be incorporated into polystyrene as side chains by the free‐radical copolymerization of polystyrene with silane‐coupling agents, and simultaneously polystyrene–silica hybrid materials with covalent bonds between two phases were formed via the sol‐gel reaction. The 3‐(trimethoxysilyl)‐propyl‐methacrylate (MPS) systems were found to be more homogeneous than the corresponding allytrimethoxysilane hybrid system of equal molar content. In the MPS‐introduced system, the thermal properties of the materials were greatly affected by the presence of MPS. FTIR results indicate successful formation of the silica networks and covalent bonding formation of coupling agents with styrene. The homogeneity of polystyrene–silica systems was examined by scanning electron microscope and atomic force microscope. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 2074–2083, 2002
Influences of some polymerization conditions on particle properties of suspension poly(vinyl chloride) resin
Authors: Bao Y. Z. , Brooks B. W.
Published: October 2002

Effects of polymerization temperature, conversions, and nonionic surfactant on the particle properties of suspension poly(vinyl chloride) (PVC) resins were investigated. It was shown that polymerization temperature has no significant influences on the mean particle size of PVC resin, and that the cold plasticiser absorption (CPA) of resin decreases linearly with the increase of polymerization temperature. Agglomeration of VCM droplets finishes before 20% conversion, and the mean particle size keeps almost constant at later stages of the polymerization process, but the CPA continues decreasing with the increase of conversion. Scanning Electron Microscopy (SEM) micrographs show that the degree of agglomeration of primary particles increases with polymerization temperature and conversion. Addition of nonionic surfactant to the VCM suspension system, as a secondary suspending agent, has a great influence on the particle properties of PVC resin. The particle size and CPA increase as the concentration of nonionic surfactant increases. The nonionic surfactant with a greater HLB value is more effective in raising the mean particle size, but is less effective in raising the CPA. It is considered that the added nonionic surfactant would be absorbed faster on the VCM/water interface than the poly(vinyl alcohol) (PVA), which was used as the primary suspending agent. Because the colloid protection ability of the nonionic surfactant is less than that of PVA, droplets become less resistant to coalescence, and the mean particle size of the final PVC resin increases consequently. The increase of porosity is caused by the combined effects of increased coalescence of VCM droplets and the nonionic surfactant's steric effect inside the droplets. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 1544–1552, 2002
Synthesis and characterization of water‐soluble polymeric adhesion promoter for epoxy resin/copper joints
Authors: Song S. M. , Cho K. , Park C. E. , Yun H. K. , Oh S. Y.
Published: October 2002

Nobel polymeric adhesion promoter soluble in water was synthesized to improve the adhesion strength of copper lead frame/epoxy molding compound (EMC) joints. N‐(4‐phenolyl)‐(benzotriazole‐5‐carboxylic)amide (PBCA) was synthesized by reacting benzotriazole‐5‐carboxylic acid (CBTA) with 4‐aminophenol. Poly[acrylic‐co‐4‐(5‐benzotriazole)amido phenyl acrylate] (PAB) was synthesized by reacting poly acryloyl chloride with PBCA. The adhesion strength of PAB‐treated copper lead frame/epoxy resin joints increased with the increase of PBCA content in PAB by forming more Cu‐triazole complex. The adhesion strength of PAB‐treated copper lead frame/epoxy resin joints having high PBCA content in PAB (more than 0.3 of mole ratio) is comparable to that of polybenzimidazole (PBI)‐treated copper lead frame/epoxy resin joints. However, the adhesion strength of PAB‐treated copper/epoxy resin joints decreased with the increase of PAB treatment time since Cu‐triazole complex particles were formed on PAB‐treated copper surface and acted as defects. The initial adhesion strength was maintained by suppressing the formation of Cu‐triazole complex particles using PAB having low PBCA contents (0.003 mole ratio of PBCA). The solubility of PAB in water was dependent on the mole ratio of carboxylic acid to PBCA in PAB. The increase of carboxylic acid content in PAB improved the solubility of PAB in water but decreased the adhesion strength with copper. PAB containing 0.03 mole ratio of PBCA was soluble in water. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 2202–2210, 2002