bluuebunny/crossref_metadata_2025 huggingface dataset:
MUC1 Initiates Src-CrkL-Rac1/Cdc42–Mediated Actin Cytoskeletal Protrusive Motility after Ligating Intercellular Adhesion Molecule-1
Authors: Shen Qiang , Rahn Jennifer J. , Zhang Jing , Gunasekera Nirosha , Sun Xuejun , Shaw Andrew R.E. , Hendzel Michael J. , Hoffman Pat , Bernier Ashlyn , Hugh Judith C.
Published: April 2008

MUC1, a transmembrane glycoprotein of the mucin family, when aberrantly expressed on breast cancer cells is correlated with increased lymph node metastases. We have previously shown that MUC1 binds intercellular adhesion molecule-1 (ICAM-1) on surrounding accessory cells and facilitates transendothelial migration of MUC1-bearing cells. Nevertheless, the underlying molecular mechanism is still obscure. In the present study, we used a novel assay of actin cytoskeletal reorganization to show that by ligating ICAM-1, MUC1 triggers Rac1- and Cdc42-dependent actin cytoskeletal protrusive activity preferentially at the heterotypic cell-cell contact sites. Further, we show that these MUC1/ICAM-1 interaction–initiated lamellipodial and filopodial protrusions require Src family kinase and CT10 regulator of kinase like (CrkL) accompanied by the rapid formation of a Src-CrkL signaling complex at the MUC1 cytoplasmic domain. Through inhibition of Src kinase activity, we further revealed that Src is required for recruiting CrkL to the MUC1 cytoplasmic domain as well as mediating the observed actin cytoskeleton dynamics. These findings suggest a novel MUC1-Src-CrkL-Rac1/Cdc42 signaling cascade following ICAM-1 ligation, through which MUC1 regulates cytoskeletal reorganization and directed cell motility during cell migration. (Mol Cancer Res 2008;6(4):555–67)
Expression of Glucose Transporter-1 and -3 in the Head and Neck Carcinoma – The Correlation of the Expression with the Biological Behaviors
Authors: Zhou Shuihong , Wang Shenqing , Wu Qiuliang , Fan Jun , Wang Qinying
Published: April 2008

Objective: The aim of this study was to determine the biological significance of glucose transporter (Glut)-1 and Glut-3 expression in head and neck carcinoma (HNC). Methods: We detected expression of Glut-1 and -3 in 38 HNCs and analyzed the relationship between increased expression and the biological behavior of HNCs. Results: The gene expression levels of Glut-1 and -3 in HNCs were significantly higher than those in adjacent cancer tissues or in normal tissues. The GLUT-1 gene level was correlated with the lymph node metastasis and clinical stage of 38 HNCs, and the GLUT-3 gene level was correlated with the lymph node metastasis of 38 HNCs. Of the 38 cases, 30 showed positive expression of Glut-1 protein. The Glut-1 protein expression level was related to the lymph node metastasis and clinical stage of 38 HNCs. However, there was no case that expressed Glut-3 protein. The high expression of Glut-1 gene and protein was associated with poor survival in the HNCs. GLUT-3 gene expression was not associated with the prognosis of HNCs. Conclusions:GLUT-1 gene expression level and protein expression were correlated with lymph node metastasis, poor survival and clinical stage of HNCs. The GLUT-3 gene expression level was high in HNCs, and its expression was associated with an increased incidence of lymph node metastasis of HNCs.
Evaluation of Factors Associated with Chronic Low Back Pain in Hemodialysis Patients
Authors: Cristofolini Tatiana , Draibe Sergio , Sesso Ricardo
Published: April 2008

Background/Aims: Low back pain is a common and disabling symptom that has not been properly studied in hemodialysis patients. The aim of this study was to evaluate factors associated with chronic low back pain in these patients. Methods: We evaluated 205 patients undergoing chronic hemodialysis. Data were obtained through medical records, patient interviews and physical examination. Balance was evaluated through the Tinetti scale. The muscular strength was evaluated through the quadriceps muscle manual test and the Kendall scale graduation. Results: 74 patients (36.1%) had low back pain. They were older (p = 0.020), undergoing dialysis for a longer period (p = 0.071) and had more comorbidities than patients without lumbar pain. Among the patients with low back pain, 75.7% presented balance disorders and 59.5% muscular weakness. In multivariate analysis the factors related to low back pain were balance deficit (OR: 9.30; 95% CI: 2.77–31.20), muscular strength deficit (OR: 14.33; 95% CI: 4.55–45.19), arterial hypertension (OR: 4.51; 95% CI: 1.32–15.37), bone disease (OR: 43.39; 95% CI: 11.51–163.53) and cerebrovascular disease (OR: 20.21; 95% CI: 3.28–124.65). Conclusions: Chronic low back pain is common in hemodialysis patients and is associated with muscle weakness, balance disorders, and comorbidities.
Acquired Unilateral Melanocytic Nevi in Otherwise Normal Skin
Authors: Yu Xijun , Nagai Hiroshi , Nishigori Chikako , Horikawa Tatsuya
Published: April 2008

We describe a case with numerous melanocytic nevi in otherwise normal skin. A 5-year-old girl presented with more than 100 small pigment lesions on her left arm, shoulder and upper back without underlying light brown macule. The pigment lesions were first found on her left forearm at 3 months old and gradually increased along with her growth. Skin biopsy from a pigmented lesion shows a pathological change in compound-type melanocytic nevus without any atypical changes. Speckled lentiginous nevus is known to have multiple melanocytic lesions on the underlying brown macule from birth. Partial unilateral lentiginosis is characterized by unilateral lentigines with histopathological changes in lentigo but not melanocytic proliferation in the dermis. Agminated melanocytic nevi tend to be clustered together in a circumscribed area, whereas in the present case melanocytic nevi were segmentally arranged but not agminated. We consider that this is an unusual type of mosaicism of melanocytic disorders.
Distribution of APOE Genotypes in a Memory Clinic Cohort
Authors: van der Flier W.M. , Pijnenburg Y.A.L. , Schoonenboom S.N.M. , Dik M.G. , Blankenstein M.A. , Scheltens P.
Published: April 2008

Aim: To describe the distribution of apolipoprotein E (APOE) genotypes in a cohort of memory clinic patients. Methods: We included 749 memory clinic patients. Diagnoses were made in a multidisciplinary consensus meeting and the APOE genotype was determined. The community-based cohort of the Longitudinal Aging Study Amsterdam was used as control population (n = 2,233). Results: In the memory clinic sample, there were 173 patients with subjective complaints, 125 patients with mild cognitive impairment (MCI), 251 patients with Alzheimer disease (AD), 107 patients with another type of dementia, and 93 patients with another neurologic or psychiatric diagnosis. The APOE allele distribution differed among groups. There was no difference in the prevalence of the Ε2 allele, but there were differences in distribution of the Ε3 and Ε4 alleles. Compared with the control population (15%), the prevalence of APOE Ε4 was increased among patients with subjective complaints (22%), MCI (36%), AD (42%) and other types of dementia (25%). Conclusion: We observed an increased prevalence of APOE Ε4 in patients with MCI and subjective complaints. This finding is of great clinical importance as nondemented patients positive for APOE Ε4 could be identified as being at genetic risk of AD, and for that reason monitored more closely.
Cognitive Function and Psychiatric Symptoms in Early- and Late-Onset Frontotemporal Dementia
Authors: Shinagawa Shunichiro , Toyota Yasutaka , Ishikawa Tomohisa , Fukuhara Ryuji , Hokoishi Kazuhiko , Komori Kenjiro , Tanimukai Satoshi , Ikeda Manabu
Published: April 2008

Background/Aim: Some recent studies mentioned that late-onset frontotemporal dementia (FTD) is more common than previously assumed. Although much research has been done in the field, there are no systematic studies which have compared clinical characteristics of early- and late-onset FTD. The aim of this study was to compare cognitive function and psychiatric symptoms in patients with early- and late-onset FTD. Methods: Study participants were consecutive outpatients. There were 35 FTD patients; their mean age at onset was 63.0 years. We studied sex, education, duration from onset to consultation, Clinical Dementia Rating (CDR) scores, Mini-Mental State Examination (MMSE) scores, Raven’s Coloured Progressive Matrices (RCPM) scores, and Neuropsychiatric Inventory (NPI) scores at first consultation of early- and late-onset FTD patients. Results: There were no significant differences in sex ratio, education, CDR scores, and duration from onset to consultation. There were significant differences in the total MMSE scores, ‘three-word recall task’, ‘construction task’, and RCPM scores; late-onset groups scored significantly lower than early-onset groups. There were significant differences in the apathy domain of NPI and total NPI scores; late-onset groups scored significantly higher than early-onset groups. Conclusion: Late-onset FTD patients may have memory and visuospatial deficits in addition to their behavioural changes, even if they are clinically diagnosed according to consensus diagnostic criteria. They also present more apathy, and they may have a different histolopathological background.
Effect of ApoE Genotype on Response to Donepezil in Patients with Alzheimer’s Disease
Authors: Choi Seong Hye , Kim Sang Yun , Na Hae Ri , Kim Byung-Kun , Yang Dong Won , Kwon Jay C. , Park Mee Young
Published: April 2008

Background/Aims: The possible influence of apolipoprotein E (ApoE) genotype on the response to acetylcholinesterase inhibitor therapy in patients with Alzheimer’s disease (AD) remains a matter of controversy. In order to address this issue, we investigated the effects of ApoE genotype on the clinical response to donepezil in patients with mild to moderate AD. Methods: An open study was carried out in 51 patients with probable AD who were treated with 5–10 mg of donepezil per day for 48 weeks. Results:  Eighteen (35.3%) of the 51 patients had 1 or 2 ApoE Ε4 alleles. ApoE Ε4 carriers with AD showed a mean 1.1-point increase from the baseline score of 23.9 on the 70-point Alzheimer’s Disease Assessment Scale-Cognitive Component at 48 weeks, while the ApoE Ε4 noncarrier group showed a 3.1-point increase from the baseline score of 22.5 (p = 0.03). The ApoE Ε4 carrier group exhibited a mean 0.13-point worsening from the baseline score of 0.97 on the Korean Instrumental Activities of Daily Living at 48 weeks, while the ApoE Ε4 noncarrier group exhibited a 0.17-point worsening from the baseline score of 0.64 (p = 0.05). Conclusion: AD patients who carry the ApoE Ε4 allele may respond more favorably to donepezil than Ε4 noncarriers.
Vascular Cognitive Impairment: Prodromal Stages of Ischemic Vascular Dementia
Authors: Ramos-Estébanez Ciro , Moral-Arce Ignacio , Muñoz-Arrondo Roberto , González-Mandly Andrés , Matorras-Galán Pedro , González-Macias Jesús , Hernández-Hernández José Luis
Published: April 2008

Background/Aims: To describe the natural history of the prodromal stages of ischemic vascular dementia (pVaD). Methods: A sample of 314 inpatients with pVaD or a clini- cal diagnosis of vascular dementia (VaD; lacunar state, Binswanger’s disease, pure cortical VaD, corticosubcortical and strategic infarctions) admitted to a teaching tertiary center during a 13-year period was assessed (retrospectively n = 88, prospectively n = 226). Prospective neuropsychological assessment consisted of Mini Mental State Examination, Revised Wechsler Adult Intelligence Scale, Exit-25, Trail Making tests, Blessed Dementia Scale and Camdex H, Global Depression Scale and Hamilton Depression Rating Scale tests. Univariate analysis and logistic regressions are displayed. Results: An unrecognized pVaD was related with a clinical onset with cognitive impairment no dementia (CIND) versus symptomatic cerebrovascular events (p < 0.0001), and with being under therapy with anticoagulant or antiplatelet agents (p < 0.01). Age <85 years at diagnosis of VaD (p < 0.01) correlated with a delayed pVaD diagnosis. CIND onset was associated with a longer prodromal stage (p < 0.01), no clinical strokes during pVaD (p < 0.001), silent ischemia (p < 0.01) and Binswanger’s disease (p < 0.01). Conclusions: Vascular cognitive impairment remains an underdiagnosed, yet treatable entity. A brief neuropsychological examination and informant interviews should become standard practice in elderly populations with vascular risk factors. Small-vessel disease is a prevalent condition with a distinct natural history.
The Circulating Inactive Form of Matrix Gla Protein (ucMGP) as a Biomarker for Cardiovascular Calcification
Authors: Cranenburg Ellen C.M. , Vermeer Cees , Koos Ralf , Boumans Marie-Louise , Hackeng Tilman M. , Bouwman Freek G. , Kwaijtaal Martijn , Brandenburg Vincent M. , Ketteler Markus , Schurgers Leon J.
Published: April 2008

Objective: Matrix γ-carboxyglutamate (Gla) protein (MGP) is a vitamin K-dependent protein and a strong inhibitor of vascular calcification. Vitamin K deficiency leads to inactive uncarboxylated MGP (ucMGP), which accumulates at sites of arterial calcification. We hypothesized that as a result of ucMGP deposition around arterial calcification, the circulating fraction of ucMGP is decreased. Here we report on the development of an ucMGP assay and the potential diagnostic utility of monitoring serum ucMGP levels. Methods and Results: An ELISA-based assay was developed with which circulating ucMGP can be determined. Serum ucMGP levels were measured in healthy subjects (n = 165) and in four patient populations; patients who underwent angioplasty (n = 30), patients with aortic stenosis (n = 25), hemodialysis patients (n = 52), and calciphylaxis patients (n = 10). All four patient populations had significantly lower ucMGP levels. In angioplasty patients and in those with aortic stenosis, some overlap was observed with the control population. However, in the hemodialysis and calciphylaxis populations, virtually all subjects had ucMGP levels below the normal adult range. Conclusion: Serum ucMGP may be used as a biomarker to identify those at risk for developing vascular calcification. This assay may become an important tool in the diagnosis of cardiovascular calcification.
Preserved BK Channel Function in Vasospastic Myocytes from a Dog Model of Subarachnoid Hemorrhage
Authors: Jahromi Babak S. , Aihara Yasuo , Ai Jinglu , Zhang Zhen-Du , Weyer George , Nikitina Elena , Yassari Reza , Houamed Khaled M. , Macdonald R. Loch
Published: April 2008

Cerebral vasospasm after subarachnoid hemorrhage (SAH) is due to contraction of smooth muscle cells in the cerebral arteries. The mechanism of this contraction, however, is not well understood. Smooth muscle contraction is regulated in part by membrane potential, which is determined by K+ conductance in smooth muscle. Voltage-gated (Kv) and large-conductance, Ca2+-activated K+ (BK) channels dominate arterial smooth muscle K+ conductance. Vasospastic smooth muscle cells are depolarized relative to normal cells, but whether this is due to altered Kv or BK channel function has not been determined. This study determined if BK channels are altered during vasospasm after SAH in dogs. We first characterized BK channels in basilar-artery smooth muscle using whole-cell patch clamping and single-channel recordings. Next, we compared BK channel function between normal and vasospastic cells. There were no significant differences between normal and vasospastic cells in BK current density, kinetics, Ca2+ and voltage sensitivity, single-channel conductance or apparent Ca2+ affinity. Basilar-artery myocytes had no, small- or intermediate-conductance, Ca2+-activated K+ channels. The lack of difference in BK channels between vasospastic and control cells suggests alteration(s) in other K+ channels or other ionic conductances may underlie the membrane depolarization and vasoconstriction observed during vasospasm after SAH.
Interleukin-11 for Treatment of Hepatitis C-Associated ITP
Authors: Fontana Vincenzo , Dudkiewicz Pamela , Jy Wenche , Horstman Larry , Ahn Yeon S.
Published: April 2008

Background: Immune thrombocytopenic purpura (ITP) is frequently associated with chronic hepatitis C (HpC-ITP). Methods: Recombinant interleukin-11 (rIL-11), which has both thrombopoietic and anti-inflammatory properties, was evaluated in 12 patients with HpC-ITP in this pilot study. Group 1 (7 patients) was treated at high dose (50 µg/kg daily) while group 2 (5 patients) at low dose (15–35 µg/kg three/week). Results: In group 1, mean platelet counts rose from initial 54 × 109/l to 103 × 109/l (p = 0.02) and in group 2, from an initial 51 × 109/l to 74 × 109/l (p = 0.04). Antiplatelet antibody (aPlt-Ab) decreased in group 1. LFT improved in both groups. The mean HCV-RNA decreased in group 1 (p = 0.04), not in group 2. Side effects were common and troublesome, but were minimized with individualized dosing. One patient achieved good remission of both ITP and HpC lasting >2 years with low-dose maintenance. Conclusion: When used based on individual tolerance, rIL-11 appears useful in HpC-ITP.
Lentigo Maligna in a Young Adult
Authors: Ferrara Gerardo , Ligrone Luigi , Zalaudek Iris , Mordente Ines , Argenziano Giuseppe
Published: April 2008

Background: Lentigo maligna is mainly diagnosed in the elderly with severely sun-damaged skin. Observation: We describe a case of lentigo maligna in a 51-year-old woman with Fitzpatrick skin type III. Based on private photographs of the patient, we were able to ascertain that the lesion was already present at the age of 22 years. Despite the 29-year clinical history, the lesion was still entirely intraepidermal on histologic examination. Conclusion: Lentigo maligna in young adults is extremely rare, and therefore represents a diagnostic challenge for both clinicians and histopathologists.
Perspectives on The Cold War after Stalin's Death: A Missed Opportunity for Peace?
Authors: Jervis Robert L. , Maddux Thomas , Greiner Bernd
Published: April 2008

This forum presents three different perspectives on the eighth volume in the Harvard Cold War Studies Book Series, The Cold War after Stalin's Death: A Missed Opportunity for Peace? edited by Klaus Larres and Kenneth Osgood. The fifteen contributors to the book discuss changes and continuities in the international environment during the first few years after the death of Josif Stalin, seeking to focus on whether there was a chance during that period to end the Cold War. The book covers U.S.-Soviet relations in depth but also deals with numerous other European and Asian countries. Three distinguished scholars offer their assessments of The Cold War after Stalin's Death and explore some of the major issues raised by the contributors to the volume.
Improving Generalization for Temporal Difference Learning: The Successor Representation
Authors: Dayan Peter
Published: April 2008

Estimation of returns over time, the focus of temporal difference (TD) algorithms, imposes particular constraints on good function approximators or representations. Appropriate generalization between states is determined by how similar their successors are, and representations should follow suit. This paper shows how TD machinery can be used to learn such representations, and illustrates, using a navigation task, the appropriately distributed nature of the result.
Correlated Attractors from Uncorrelated Stimuli
Authors: Cugliandolo L. F.
Published: April 2008

Analytic results for a neural network model proposed to account for neurophysiological experiments in which attractors for uncorrelated patterns are found to be correlated are presented. Exact expressions for the associative attractors and their correlations are described.
Learning of Phase Lags in Coupled Neural Oscillators
Authors: Ermentrout Bard , Kopell Nancy
Published: April 2008

If an oscillating neural circuit is forced by another such circuit via a composite signal, the phase lag induced by the forcing can be changed by changing the relative strengths of components of the coupling. We consider such circuits, with the forced and forcing oscillators receiving signals with some given phase lag. We show how such signals can be transformed into an algorithm that yields connection strengths needed to produce that lag. The algorithm reduces the problem of producing a given phase lag to one of producing a kind of synchrony with a “teaching” signal; the algorithm can be interpreted as maximizing the correlation between voltages of a cell and the teaching signal. We apply these ideas to regulation of phase lags in chains of oscillators associated with undulatory locomotion.
The Role of Weight Normalization in Competitive Learning
Authors: Goodhill Geoffrey J. , Barrow Harry G.
Published: April 2008

The effect of different kinds of weight normalization on the outcome of a simple competitive learning rule is analyzed. It is shown that there are important differences in the representation formed depending on whether the constraint is enforced by dividing each weight by the same amount (“divisive enforcement”) or subtracting a fixed amount from each weight (“subtractive enforcement”). For the divisive cases weight vectors spread out over the space so as to evenly represent “typical” inputs, whereas for the subtractive cases the weight vectors tend to the axes of the space, so as to represent “extreme” inputs. The consequences of these differences are examined.
A Probabilistic Resource Allocating Network for Novelty Detection
Authors: Roberts Stephen , Tarassenko Lionel
Published: April 2008

The detection of novel or abnormal input vectors is of importance in many monitoring tasks, such as fault detection in complex systems and detection of abnormal patterns in medical diagnostics. We have developed a robust method for novelty detection, which aims to minimize the number of heuristically chosen thresholds in the novelty decision process. We achieve this by growing a gaussian mixture model to form a representation of a training set of “normal” system states. When previously unseen data are to be screened for novelty we use the same threshold as was used during training to define a novelty decision boundary. We show on a sample problem of medical signal processing that this method is capable of providing robust novelty decision boundaries and apply the technique to the detection of epileptic seizures within a data record.
Object Recognition and Sensitive Periods: A Computational Analysis of Visual Imprinting
Authors: O'Reilly Randall C. , Johnson Mark H.
Published: April 2008

Using neural and behavioral constraints from a relatively simple biological visual system, we evaluate the mechanism and behavioral implications of a model of invariant object recognition. Evidence from a variety of methods suggests that a localized portion of the domestic chick brain, the intermediate and medial hyperstriatum ventrale (IMHV), is critical for object recognition. We have developed a neural network model of translation-invariant object recognition that incorporates features of the neural circuitry of IMHV, and exhibits behavior qualitatively similar to a range of findings in the filial imprinting paradigm. We derive several counter-intuitive behavioral predictions that depend critically upon the biologically derived features of the model. In particular, we propose that the recurrent excitatory and lateral inhibitory circuitry in the model, and observed in IMHV, produces hysteresis on the activation state of the units in the model and the principal excitatory neurons in IMHV. Hysteresis, when combined with a simple Hebbian covariance learning mechanism, has been shown in this and earlier work (Földiák 1991; O'Reilly and McClelland 1992) to produce translation-invariant visual representations. The hysteresis and learning rule are responsible for a sensitive period phenomenon in the network, and for a series of novel temporal blending phenomena. These effects are empirically testable. Further, physiological and anatomical features of mammalian visual cortex support a hysteresis-based mechanism, arguing for the generality of the algorithm.
A Convergence Result for Learning in Recurrent Neural Networks
Authors: Kuan Chung-Ming , Hornik Kurt , White Halbert
Published: April 2008

We give a rigorous analysis of the convergence properties of a backpropagation algorithm for recurrent networks containing either output or hidden layer recurrence. The conditions permit data generated by stochastic processes with considerable dependence. Restrictions are offered that may help assure convergence of the network parameters to a local optimum, as some simulations illustrate.
Overgrowing forest as a possible cause for the local extinction of Vipera aspis in the northern Swiss Jura mountains
Authors: Jaggi Christoph , Baur Bruno
Published: April 2008

In the northern Swiss Jura mountains, the Asp viper Vipera aspis was common until the 1940ies. During the past 50 years many local populations went extinct and nowadays the species is considered as threatened. We compared habitat characteristics of localities with extant viper populations with those of localities where the species became extinct. These two groups of localities did not differ in exposure, altitude, inclination, soil structure and cover of ground vegetation. However, localities where the species is still found were situated more frequently at forest edges, in dry meadows and at roadsides, whereas localities in which V. aspis became extinct were situated more frequently in forests. Tree density was lower at localities where the viper is still present. The results suggest that former habitats of V. aspis became overgrown by bushes and trees, which in turn may have led to a colder, more humid and thus unfavourable microclimate for V. aspis. We conclude that logging is an essential tool to maintain suitable habitat for this thermophilous ovoviviparous reptile.
Cranial morphology of Rafetus euphraticus (Daudin, 1801) from Southeastern Anatolia
Authors: Taşkavak Ertan
Published: April 2008

Observations on cranial morphology were made on Euphrates soft-shelled turtles, Rafetus euphraticus, sampled in the Euphrates and Tigris rivers and tributaries, Southeastern Anatolia. The vomer separates the maxillaries in half of the specimens, whereas the maxillae meet on the vomer in others. The parietal has no contribution in the formation of the foramen nervi trigemini due to the contact between the prootic and the epipterygoid. There are variations in the contacts of the basisphenoid and in the formation of the trigeminal region, a prootic-epipterygoid contact participates in the trigeminal region. The contacts of the vomer-pterygoid, the vomer-basisphenoid and the vomer-pterygoid-basisphenoid are observed in some specimens. In one specimen, the parietal contacts the opisthotic. All specimens have the symphyseal ridge, althought it is weak and barely discernible.
Interactions between branchiate mole salamanders (Ambystoma talpoideum) and lesser sirens (Siren intermedia): asymmetrical competition and intraguild predation
Authors: Fauth John E.
Published: April 2008

Using field sampling and experiments in natural and artificial ponds, I studied interactions between branchiate adult mole salamanders (Ambystoma talpoideum) and lesser sirens (Siren intermedia), two top predators in temporary ponds of the southeastern United States. The abundance and distribution of these two salamanders were independent among ponds, with A. talpoideum more numerous and widespread than S. intermedia. Both species were more likely to be found in ponds near other intermittent wetlands. Within a pond, captures of these two species were negatively correlated, and a field experiment showed that paedomorphic A. talpoideum avoided traps containing S. intermedia. An experiment in artificial ponds confirmed that interactions between these two species were highly asymmetrical; S. intermedia reduced the growth and recruitment of A. talpoideum without experiencing reciprocal. positive or negative effects. These results suggest that S. intermedia competes with and is an intraguild predator of A. talpoideum, limiting its growth and controlling its recruitment.
Ecology and conservation of the Milos viper, Macrovipera schweizeri (Werner, 1935)
Authors: Nilson Göran , Andrén Claes , Ioannidis Yiannis , Dimaki Maria
Published: April 2008

The Milos viper (Macrovipera schweizeri) is nocturnal from early summer until mid-September. The typical habitat was maquis terrain with small and large bushes on gravel or rocky ground. Telemetric studies showed that cryptic basking behaviour was used during 23.5% of the localisations, and a preference for large bushes (77.7%). The mean distance moved between two succeeding days was 28.5 m (with s_x, of 47.9), and in general, the male home range covered an area of 10 to 20 ha, while the female home range was smaller. Hibernacula were south facing and situated in the middle of the home ranges. Population density was 50 adult vipers per km2 in the optimal habitats. The total population for western Milos was estimated to be around 2,500 adult vipers during the study period (1993-98). The present total population on Milos seems to be below 3,000 adult animals. The species has been isolated since the Pliocene, and adapted to a diet of passerine birds. A pattern of twice-a-year foraging during spring and autumn bird migrations was highlighted. During spring, the vipers tend to be concentrated around water pools; in the dry autumn nights they climb up trees for resting birds. In years with a cold spring or autumn, critical situations may occur with starvation, resulting in cyclic population patterns. Mid-May is the mating period. The female reproductive cycle is biennial. The sex ratio is nearly equal. Around 600 specimens reach adulthood and participate in the reproductive activities each year. Mining and fires destroy habitat. The yearly estimated removal by man and road killing of vipers is up to 500-600 adult specimens. Thus, the input and out-take of adult specimens is of the same magnitude, and equal to a yearly 25% turnover. This indicates a very delicate balance, and even a small change that increases the removed number can lead towards a rapid extinction. A conservation program is urgently needed and should include the establishment of protected areas, the closing of roads for night-time driving, and prohibition of increased mining activities.
Land salamanders of the family Hynobiidae from the Neogene and Quaternary of Europe
Authors: Venczel Márton
Published: April 2008

A new extinct genus with two new species of land salamanders of the family Hynobiidae, from the Late Miocene of Polgárdi (MN13), Hungary (Parahynobius kordosi gen. n. sp. n.) and from the Lower Pleistocene of Betfia IX/C (MQ1), Romania (Parahynobius betfianus gen. n. sp. n.), is described. The Late Miocene locality of Tardosbánya (MN12) and the Lower Pliocene locality of Osztramos 1C (MN 14), Hungary, also yielded several vertebrae, assigned with some doubt to the above genus (cf. Parahynobius). The new taxa belonged to the westernmost distributed stock of land salamanders of the Hynohius-group, which, based on the available fossil record, reached the Carpathian Basin during Late Miocene and disappeared from the area during Lower Pleistocene times. The Hynobiidae had a wider geographic distribution during the Tertiary and Quaternary compared to their present range, which is limited to Asia.
Early metamorphosis in common frog Rana temporaria tadpoles at risk of drying: an experimental demonstration
Authors: Loman Jon
Published: April 2008

Does the development rate of common frog tadpoles accelerate if their habitat dries? To study this, the water level in experimental tanks was reduced shortly before time of metamorphosis. Water level remained high in control tanks. The experiment was performed at two different tadpole densities and replicated four times, with tadpoles from different source ponds. The experimental treatment, simulating a drying pond, resulted in earlier metamorphosis while no significant difference in size at metamorphosis was found. Resources per capita decreased as a result of the decreased water level so the increase in development rate was not an effect of feeding conditions. Temperatures in the tanks were such that it is unlikely that the increased development rate was due to temperature effects. I interpret the advancement of metamorphosis as an adaptive response to the threat of drying. This response has been documented for several other anuran species. All those breed in temporary water bodies, supporting the hypothesis that the trait is an evolved adaptation for breeding in such waters.
An Analysis of Sexual Isolation in the Domestic Fowl: 1. the Basis of Homogamy in Males
Authors: Lill Alan
Published: April 2008

(I) The basis of homogamy exhibited by the adult domestic cock was investigated because of its important role in effecting potential sexual isolation between breeds and strains of chicken. (2) The importance of female plumage coloration in breed 'identification' by males was determined by modification and other tests. (3) Female plumage coloration possesses isolating value, but more so in single than in multi-coloured breeds. In the latter, discriminating cocks responded additionally to other, unknown releasers. (4) Homogamy appeared to be a largely genetic trait in domestic cocks, as judged from social isolation experiments. Homogamic-heterosexual juvenile experience very slightly enhanced the expression of homogamy by adult males, homogamic-homosexual experience did not, however. (5) Homogamy, though a comparatively stable trait, was not irreversible and could be modified by certain types of juvenile and adult social environment. (6) The present findings are advanced as a contribution to knowledge of macro- and micro-evolutionary mechanisms in avian species.
Coital Behavior in Dogs Iii. Effects of Early Isolation On Mating in Males
Authors: Beach Frank A.
Published: April 2008

Three groups of male beagles were reared from weaning to sexual maturity under special circumstances and their responses to estrous females were compared in a series of mating tests. Five dogs were reared under conditions of semi-isolation (SI). They lived in individual cages and had very little physical contact with other animals throughout the experiment. The 5 males constituting the control group also inhabited individual cages but for 15 min. each day they were set free in the colony room where they could interact with other uncaged dogs. A final group of 5 males was reared together with 5 females in a I-acre field. None of the subjects had contact with estrous bitches except during the mating tests. The copulatory performance of the control and the group-reared males was essentially the same, but that of the semi-isolates was deficient in one particular. SI males mounted estrous females as readily and as frequently as members of the other 2 groups, but the orientation of mounting was abnormal. Ninety-seven per cent of the mounts by control and group-reared males were oriented to the female's rear, whereas 39 per cent of the mounts by SI dogs were directed to the head, side, or flank of the receptive bitch. One consequence of this difference was that SI males achieved intromission in only 24 per cent of their tests, as compared with 58 per cent and 54 per cent for the control and group-reared animals.
The Integrable Variant of the Theory of Slip
Authors: Nikitin
Published: April 2008

The model of elastoplastic medium is based on the concept of slip proposed by Batdorf and Budiansky. The conditions of slip on a slip plane take into account “the local loading criterion”. Under some assumptions we succeeded in integrating the plastic shears over all possible slip planes in case of arbitrary three‐dimensional stress state and obtained an expression for the plastic strain tensor increments and the closed variant of the elastoplastic model, which turns out to be a variant of the plastic flow theory. The integration method proposed can be applied for establishing the links between local conditions and macroscopic equations, and for some other slip conditions too.
Comparative Evaluation of an Eulerian CFD and Gaussian Plume Models Based on Prairie Grass Dispersion Experiment
Authors: Demael E. , Carissimo B.
Published: April 2008

A theoretical and statistical comparison of a three-dimensional computational fluid dynamics (CFD) model with two Gaussian plume models is proposed on the Prairie Grass data field experiment for neutral conditions, using both maximum arcwise concentrations and spatially paired observations. In theory, it is impossible to have the same near-source behavior with the Eulerian CFD code as with the Gaussian plume models. The former presents the inability to account for the dependence of the turbulent diffusivity to the distance from the source, contrary to plume models for which this dependence is fitted to observations. The study described herein looks at the practical implications of these theoretical differences by comparing the two different types of models on a flat-terrain case, a situation favoring Gaussian models. The results herein show that the Eulerian CFD model gives acceptable results, both for arc-maximum concentrations and spatially paired observations. Indeed, the statistical performances are above the criteria of “good performance” commonly defined in literature. In general, the results for Eulerian code fall between those of a Gaussian model that has been fitted using the Prairie Grass dataset and those of one fitted with different datasets.
A Semiempirical Microscale Model of the Surface Energy Balance and Its Application to Two Urban Rooftops
Authors: Barzyk Timothy M. , Frederick John E.
Published: April 2008

Individual structures within the same local-scale (102–104 m) environment may experience different microscale (<103 m) climates. Urban microclimate variations are often a result of site-specific features, including spatial and material characteristics of surfaces and surrounding structures. A semiempirical surface energy balance model is presented that incorporates radiative and meteorological measurements to statistically parameterize energy fluxes that are not measured directly, including sensible heat transport, storage heat flux through conduction, and evaporation (assumed to be negligible under dry conditions). Two Chicago rooftops were chosen for detailed study. The City Hall site was located in an intensely developed urban area characterized by close-set high-rise buildings. The University rooftop was in a highly developed area characterized by three- to seven-story buildings of stone, concrete, and brick construction. Two identical sets of instruments recorded measurements contemporaneously from these rooftops during summer 2005, and results from the week of 29 July to 5 August are presented here. The model explains 83.7% and 96% of the variance for the City Hall and University sites, respectively. Results apply to a surface area of approximately 1260 m2, at length scales similar to the dimensions of built structures and other urban elements. A site intercomparison revealed variations in surface energy balance components caused by site-specific features and demonstrated the relevance of the model to urban applications.
An Evaluation of Scatterometer-Derived Oceanic Surface Pressure Fields
Authors: Patoux Jérôme , Foster Ralph C. , Brown Robert A.
Published: April 2008

Oceanic surface pressure fields are derived from the NASA Quick Scatterometer (QuikSCAT) surface wind vector measurements using a two-layer similarity planetary boundary layer model in the midlatitudes and a mixed layer planetary boundary layer model in the tropics. These swath-based surface pressure fields are evaluated using the following three methods: 1) a comparison of bulk pressure gradients with buoy pressure measurements in the North Pacific and North Atlantic Oceans, 2) a least squares difference comparison with the European Centre for Medium-Range Weather Forecasts (ECMWF) surface pressure analyses, and 3) a parallel spectral analysis of the QuikSCAT and ECMWF surface pressure fields. The correlation coefficient squared between scatterometer-derived pressure fields and buoys is found to be R2 = 0.936. The average root-mean-square difference between the scatterometer-derived and the ECMWF pressure fields ranges from 1 to 3 hPa, depending on the latitude and season, and decreases after the assimilation of QuikSCAT winds in the ECMWF numerical weather prediction model. The spectral components of the scatterometer-derived pressure fields are larger than those of ECMWF surface analyses at all scales in the midlatitudes and only at shorter wavelengths in the tropics.
Snowfall Retrievals Using Millimeter-Wavelength Cloud Radars
Authors: Matrosov Sergey Y. , Shupe Matthew D. , Djalalova Irina V.
Published: April 2008

It is demonstrated that millimeter-wavelength radars that are designed primarily for cloud studies can be also used effectively for snowfall retrievals. Radar reflectivity–liquid equivalent snowfall rate (Ze–S) relations specifically tuned for Ka- and W-band radar frequencies are applied to measurements taken by vertically pointing ground-based 8-mm cloud radars (MMCR) that are designed for the U.S. Department of Energy’s Atmospheric Radiation Measurement (ARM) Program and by the nadir-pointing spaceborne 94-GHz CloudSat radar. Comparisons of the MMCR-based snowfall accumulations estimated during experimental events with no significant snowflake riming and controlled gauge measurements indicated an 87% standard deviation between radar and gauge data that is consistent with the uncertainties in the coefficients of the Ze–S relations resulting from variability in snowflake microphysical properties. Comparisons of CloudSat-based snowfall-rate retrievals in heavy snowfall were consistent with estimates from surface S-band precipitation surveillance radars made using algorithms that were specifically designed for use with these radars. A typical difference between the CloudSat and the S-band precipitation radar estimates of snowfall rate for approximately collocated resolution pixels was within a factor of 2, which is of the order of the uncertainty of each estimate. The results of this study suggest that the ground-based and satellite-borne radars operating at Ka and W bands can provide valuable retrieval information on vertical profiles of snowfall, which is an important component of the global water cycle. This information is particularly important in Arctic regions where precipitation information from other sources is scarce.
Evaluation of the Ensemble Transform Analysis Perturbation Scheme at NRL
Authors: McLay Justin G. , Bishop Craig H. , Reynolds Carolyn A.
Published: April 2008

The ensemble transform (ET) scheme changes forecast perturbations into analysis perturbations whose amplitudes and directions are consistent with a user-provided estimate of analysis error covariance. A practical demonstration of the ET scheme was undertaken using Naval Research Laboratory (NRL) Atmospheric Variational Data Assimilation System (NAVDAS) analysis error variance estimates and the Navy Operational Global Atmospheric Prediction System (NOGAPS) numerical weather prediction (NWP) model. It was found that the ET scheme produced forecast ensembles that were comparable to or better in a variety of measures than those produced by the Fleet Numerical and Oceanography Center (FNMOC) bred-growing modes (BGM) scheme. Also, the demonstration showed that the introduction of stochastic perturbations into the ET forecast ensembles led to a substantial improvement in the agreement between the ET and NAVDAS analysis error variances. This finding is strong evidence that even a small-sized ET ensemble is capable of obtaining good agreement between the ET and NAVDAS analysis error variances, provided that NWP model deficiencies are accounted for. Last, since the NAVDAS analysis error covariance estimate is diagonal and hence ignores multivariate correlations, it was of interest to examine the ET analysis perturbations’ spatial correlation. Tests showed that the ET analysis perturbations exhibited statistically significant, realistic multivariate correlations.
The Evolution of Morning Convective Systems over the U.S. Great Plains during the Warm Season. Part II: A Climatology and the Influence of Environmental Factors
Authors: Hane Carl E. , Haynes John A. , Andra David L. , Carr Frederick H.
Published: April 2008

Mesoscale convective systems that affect a limited area within the southern plains of the United States during late morning hours during the warm season are investigated. A climatological study over a 5-yr period documents the initiation locations and times, tracks, associated severe weather, and relation to synoptic features over the lifetimes of 145 systems. An assessment is also made of system evolution in each case during the late morning. For a subset of 48 systems, vertical profiles of basic variables from Rapid Update Cycle (RUC) model analyses are used to characterize the environment of each system. Scatter diagrams and discriminant analyses are used to assess which environmental variables are most promising in helping to determine which of two classes of evolutionary character each system will follow.
Ensemble Held–Suarez Test with a Spectral Transform Model: Variability, Sensitivity, and Convergence
Authors: Wan Hui , Giorgetta Marco A. , Bonaventura Luca
Published: April 2008

The idealized test case proposed by Held and Suarez is carried out with the atmospheric general circulation model ECHAM5 of the Max Planck Institute for Meteorology. The aim is to investigate the sensitivity of the solutions of the spectral dynamical core to spatial and temporal resolution, and to evaluate the numerical convergence of the solutions. Low-frequency fluctuations at time scales as long as thousands of days are found in ultralong integrations. To distinguish the effect of changed resolution from the fluctuations caused by the internal variability, the ensemble method is employed in experiments at resolutions ranging from T31 to T159 with 16 to 81 vertical levels. Significance of the differences between ensembles is assessed by three different statistical tests. Convergence property of the numerical solution is concisely summarized by a ratio index.

Results show that the simulated climate state in the Held–Suarez test is sensitive to spatial resolution. Increase of horizontal resolution leads to slight weakening and poleward shift of the westerly jets. Significant warming is detected in high latitudes, especially near the polar tropopause, while the tropical tropopause becomes cooler. The baroclinic wave activity intensifies considerably with increased horizontal resolution. Higher vertical resolution also leads to stronger eddy variances and cooling near the tropical tropopause, but equatorward shift of the westerly jets. The solutions show an indication of convergence at T85L31 resolution according to all the three statistical tests applied. Differences between integrations with various time steps are judged to be within the noise level induced by the inherent low-frequency variability.
The Impact of Trade Wind Strength on Precipitation over the Windward Side of the Island of Hawaii
Authors: Esteban Mary Ann , Chen Yi-Leng
Published: April 2008

The effects of trade wind strength and the diurnal heating cycle on the production of summer trade wind rainfall on the windward side of the island of Hawaii are examined from the data collected from the Hawaiian Rainband Project (HaRP) during 11 July–24 August 1990 and from National Weather Service Hydronet and National Climatic Data Center rain gauge data during 11 July–24 August for the years 1997–2000.

For strong trades, the daily rainfall totals on the windward lowlands west of Hilo are higher with a nocturnal maximum there due to the convergence of the katabatic flow and the incoming decelerating trade wind flow, and orographic lifting aloft. The maximum rainfall axis shifts farther inland when trades are stronger. Except in the late afternoon hours, rainfall amounts on the windward side are higher when trades are stronger. For weak trades (≤5 m s−1), the rainfall distributions have a pronounced late afternoon maximum on the windward slopes due to the development of anabatic winds. The nocturnal rainfall over the windward lowlands and the early morning coastal rainfall are lower when trades are weaker.