bluuebunny/crossref_metadata_2025_split huggingface dataset:
Hybridization, polyploidy and speciation inSpartina(Poaceae)
Authors: Ainouche Malika L. , Baumel Alex , Salmon Armel , Yannic Glenn 
Published: December 2004

SummaryHybridization and polyploidy are well illustrated in the genusSpartina. This paper examines how recent molecular approaches have helped our understanding of the past and recent reticulate history of species, with special focus on allopolyploid speciation.Spartinaspecies are tetraploid, hexaploid or dodecaploid perennials, most of them being native to the New World. The molecular phylogeny indicates an ancient split between the tetraploid and the hexaploid species, withS.argentinensisas sister to the hexaploid lineage. Recent hybridization and polyploidization events involved hexaploid species, resulting from introductions of the east‐AmericanS. alterniflora. In California, ongoing hybridizations with its sister speciesS. foliosaresult in introgressant hybrid swarms. In Europe, hybridization withS. maritimaresulted inS. × neyrautii(France) andS. × townsendii(England), with.S. alternifloraas the maternal parent. The allopolyploidS. anglicaresulted from chromosome doubling ofS. × townsendii.This young allopolyploid contains divergent homoeologous subgenomes that have not undergone significant changes since their reunion. Hybridization, rather than genome duplication, appears to have shaped the allopolyploid genome at both the structural and epigenetic levels.
Integration of populations and differentiation of species
Authors: Rieseberg Loren H. , Church Sheri A. , Morjan Carrie L. 
Published: December 2004

SummaryThe framework for modern studies of speciation was established as part of the Neo‐Darwinian synthesis of the early twentieth century. Here we evaluate this framework in the light of recent empirical and theoretical studies. Evidence from experimental studies of selection, quantitative genetic studies of species’ differences, and the molecular evolution of ‘isolation’ genes, all agree that directional selection is the primary cause of speciation, as initially proposed by Darwin. Likewise, as suggested by Dobzhansky and Mayr, gene flow does hold species together, but probably more by facilitating the spread of beneficial mutants and associated hitchhiking events than by homogenizing neutral loci. Reproductive barriers are important as well in that they preserve adaptations, but as has been stressed by botanists for close to a century, they rarely protect the entire genome from gene flow in recently diverged species. Contrary to early views, it is now clear that speciation can occur in the presence of gene flow. However, recent theory does support the long‐held view that population structure and small population size may increase speciation rates, but only under special conditions and not because of the increased efficacy of drift as suggested by earlier authors. Rather, low levels of migration among small populations facilitates the rapid accumulation of beneficial mutations that indirectly cause hybrid incompatibilities.
Rapid accumulation of polyphosphate in extraradical hyphae of an arbuscular mycorrhizal fungus as revealed by histochemistry and a polyphosphate kinase/luciferase system
Authors: Ezawa Tatsuhiro , Cavagnaro Timothy R. , Smith Sally E. , Smith F. Andrew , Ohtomo Ryo 
Published: December 2004

SummaryThe rate of polyphosphate accumulation in extraradical hyphae of an arbuscular mycorrhizal fungus was investigated by conventional histochemistry and a new enzymatic method using a bacterial enzyme, polyphosphate kinase. Marigold (Tagetes patula cv. Bonanza Orange) was inoculated with Archaeospora leptoticha and grown under P‐deficient conditions. Extraradical hyphae were harvested at 0, 1, 3 and 24 h after 1 mm P‐application. PolyP levels were assessed by both metachromasy of Toluidine blue O and polyphosphate kinase which converted polyP to ATP followed by the ATP‐luciferase assay. Percentage of hyphae with metachromatic granules was increased from 25 to 44% from 0 to 1 h, and a maximum of 50% was reach by 3 h. Polyphosphate content was doubled from 1 to 3 h after P‐application (4.8–10.0 mol as Pi mg−1 protein) at a rate of 46.4 ± 15.1 nmol min−1 mg−1. The rate of polyphosphate accumulation in the hyphae was surprisingly rapid as those of polyphosphate‐hyper accumulating microorganisms. The enzymatic method employed in the present study allows highly specific and sensitive assessment of polyphosphate in the mycorrhizal system.
Changes in rolandic mu rhythm during observation of a precision grip
Authors: Muthukumaraswamy S.D. , Johnson B.W. 
Published: December 2004

AbstractWe recorded 128‐channel EEG from 16 participants while they observed, imitated, and self‐initiated the precision grip of a manipulandum. Mu rhythm amplitudes were significantly lower during observation of a precision grip than during observation of a simple hand extension without object interaction. Scalp topographies for subtractions of observation, imitation, and execution conditions from the control condition showed a high degree of congruence, supporting the notion of a human observation–execution matching system. Surface Laplacian transformations suggest that the decrease in mu amplitude during precision grip observation reflects desynchronization of mu rhythm generators in the sensorimotor cortex. These results support the hypothesis that sensorimotor cortex is a neural substrate involved in the representation of both self‐ and other‐generated actions and show the mu rhythm is sensitive to subtle changes in observed motor behavior.
Lysophospholipid Enhancement of Human T Cell Sensitivity to Diphtheria Toxin by Increased Expression of Heparin‐Binding Epidermal Growth Factor
Authors: Goetzl Edward J. , Kong Yvonne , Kenney John S. 
Published: December 2004

The effects of lysophosphatidic acid (LPA) and sphingosine 1–phosphate (S1P) on T cell expression of heparin‐binding epidermal growth factor–like growth factor (HB‐EGF), the diphtheria toxin (DT) receptor, were investigated in the Tsup‐1 cultured line of human CD4+ 8+ 3low T lymphoblastoma cells. Tsup‐1 cells bear endothelial differentiation gene (edg)‐2 and ‐4‐encoded G protein–coupled receptors (GPCRs) for LPA and Edg‐3 and ‐5 GPCRs for S1P. Suppression by DT of Tsup‐1 cell protein synthesis was enhanced by LPA and S1P, with lipid structural specificity similar to that required for their recognition by Edg receptors. LPA and S1P increased the Tsup‐1 cell level of immunoreactive HB‐EGF, and neutralizing antibodies to HB‐EGF inhibited LPA and S1P enhancement of Tsup‐1 cell susceptibility to DT. Stabilized transfection of Tsup‐1 cells with a combination of plasmids encoding Edg‐2 plus ‐4 antisense mRNA suppressed the levels of Edg‐2 and ‐4, but not Edg‐3 and ‐5, in Western blots and reduced in parallel the increments in HB‐EGF and susceptibility to DT evoked by LPA but not S1P. Similar transfection with Edg‐3 plus ‐5 antisense plasmids suppressed Tsup‐1 cell levels of immunoreactive Edg‐3 and ‐5, but not Edg‐2 or ‐4, and concurrently reduced S1P‐, but not LPA‐, induced Tsup‐1 cell increases in both HB‐EGF and susceptibility to DT. Edg GPCR‐mediated LPA and S1P enhancement of T cell sensitivity to DT, thus, may be attributable to increased expression of the DT receptor HB‐EGF.
Thalassemia and Malaria: New Insights into an Old Problem
Authors: Clegg John B. , Weatherall David J. 
Published: December 2004

The hemoglobinopathies are probably the world’s most common genetic diseases: The World Health Organization has estimated that at least 5% of the population are carriers for one or other of the most serious forms, the α‐ and β‐thalassemias and the structural variant hemoglobins S, C, and E, which are found at polymorphic frequencies in many countries. All these hemoglobinopathies are believed to provide protection against malaria, and it is thought that, in malarial regions of the world, natural selection has been responsible for elevating and maintaining their gene frequencies, an idea first proposed 50 years ago by J.B.S. Haldane.Epidemiological studies undertaken in the 1950s on hemoglobin S in Africa provided support for the “malaria hypothesis,” but until recently it has proved extremely difficult to verify it for the thalassemias. The application of molecular methods has, however, provided new opportunities to address this old question. Population and molecular genetic analysis of thalassemia variants, and microepidemiological studies of the relationship between α‐thalassemia and malaria in the southwest Pacific, have provided unequivocal evidence for protection. Surprisingly, some of this protection appears to derive from enhanced susceptibility in very young thalassemic children to both Plasmodium falciparum and, especially, P. vivax, and this early exposure appears to provide the basis for better protection in later life.
A Novel System to Diagnose Cutaneous Adverse Drug Reactions Employing the Cellscan—Comparison with Histamine Releasing Test and Inf‐γ Releasing Test
Authors: Goldberg Ilan , Gilburd Boris , Kravitz Martine Szyper , Kivity Shmuel , Ben Chaim Berta , Klein Tirza , Schiffenbauer Yael , Trubniykovr Ela , Brenner Sarah , Shoenfeld Yehuda 
Published: December 2004

Background: There are several mechanisms to describe allergic drug
reactions yet the methods to diagnose them are limited.Objective: To compare several conventional clinical and laboratory
methods to diagnose skin reactions to drugs
to a new method of diagnosing drug reactions by the CellScan system.Methods: The study entailed 21 patients who were diagnosed as
suffering from drug eruptions, and 105 healthy controls with no history of drug
allergy. The drugs were classified into two groups according to suspicion of
causing drug allergy: high and low. Most of the patients were on more than
one drug, leading to 41 patient‐drug interactions (assays). Histamine
releasing test (HRT), interferon (INF)‐γ releasing test and CellScan
examination were performed on lymphocytes of the patients and controls.Results: The HRT was interpreted as positive in 9 out of 18 (50%)
patients and in 13 out of 35 (37%) assays. Based on the INF‐γ releasing test,
positive results were observed in 16 out of 21 (76%) patients and in 24 out of 41
(59%) assays. In the CellScan test (CST), positive results were observed in 17
out of 21 (81%) patients and in 29 out of 41 (71%) assays. The rate of identifying
the drug for eruption in the high suspicion level drugs was 9 out of 22 (41%)
assays in the HRT, 20 out of 24 (83%) assays in the INF‐γ releasing test, and 21
out of 24 (87%) studies with the CellScan method. The rate of determining of
the drug that caused the eruption in the low suspicion level drugs was 4 out of
13 (31%) in the HRT, 4 out of 17 (24%) assays in the INF‐γ releasing test, and 8
out of 17 (47%) analyses in the CST. When examined
in the CellScan, 99 out of 105 (94%) controls were interpreted as negative.Conclusion: This preliminary study indicates that the CellScan seems to
be an easy and promising method for the detection of drugs responsible for
adverse skin reactions. In contrast to the HRT and to the Interferon‐γ secretion
test, the CellScan method is characterized by its ability to track and monitor
the reaction of individual cells. By measuring the kinetic parameters of selected
cells before and after adding the suspected drug, we were able to identify
the culprit drug. The CellScan method had the highest sensitivity, and the
interferon‐γ secretion test had the highest specificity for detection of the culprit
drug. In contrast, the analysis of 105
normal control sera disclosed a high specificity of 94% for the CellScan method.
The Effects of Enterococcus faecium and Selenium on Methotrexate Treatment in Rat Adjuvant‐induced Arthritis
Authors: Rovenský Jozef , šv­k Karol , Mat′ha Vladim­r , Itok Richard , Ebringer Ladislav , Ferenčík Miroslav , StanĨ­ková Mária 
Published: December 2004

The effects of probiotic bacteria Enterococcus faecium (EF)
and selenium were studied on methotrexate (MTX) treatment in rats with adjuvant
arthritis (AA).Arthritic rats were preventive treated orally with the following substances:
lyophilized EF (15 mg/kg/day, 5 days a week); sodium selenite pentahydrate
(SSe, 0.050 mg/kg containing 0.015 mg/kg selenium, 5 days a week); MTX (0.6
mg/kg/week), and their combinations for the period of 50 days from adjuvant
application. Levels of serum albumin, serum nitrite/nitrate concentrations, hind
paw swelling, arthrogram scores, whole body bone mineral density (BMD), and
bone erosions were evaluated
as markers of inflammation and destructive changes associated with arthritis.Long‐term preventive treatment with low‐dose MTX significantly inhibited
the markers of both inflammation and arthritis. EF or SSe when administered
singly or in combination had no significant effect on given parameters in arthritic
rats. EF but not SSe potentiated the beneficial effects of MTX, which resulted in
a more significant reduction of hind paw swelling, arthrogram scores and whole
body BMD decrease. EF had a tendency to improve also the effect of MTX on
serum albumin and nitrite/nitrate concentrations.Our results indicate that EF may increase the preventive effect of MTX
treatment in
rat AA by improving its anti‐inflammatory and anti‐arthritic effects.
Privatization morphs into ‘publicization’: businesses look a lot like government
Authors: Sellers Martin P. 
Published: December 2004

Private companies become like public agencies because competition for contracts is keen and they must be perceived by the contacting agent, government, as being agreeable with the government's demands in order to be contracted with again. Government makes suggestions, sets requirements, and provides recommendations to private companies which, over time, cause the private companies/facilities to look more and more like government agencies – and company managers are left pressed between their need to re‐contract and the business instincts and acumen for which they’ve presumably been contracted with in the first place.This paper will briefly visit the common arguments for and against privatization. Additionally, the results of a limited study of the effect of publicization on private prison companies operating nationally in the US will be examined.
Distributions Generated by Perturbation of Symmetry with Emphasis on a Multivariate Skewt-Distribution
Authors: Azzalini Adelchi , Capitanio Antonella 
Published: December 2004

SummaryA fairly general procedure is studied to perturb a multivariate density satisfying a weak form of multivariate symmetry, and to generate a whole set of non-symmetric densities. The approach is sufficiently general to encompass some recent proposals in the literature, variously related to the skew normal distribution. The special case of skew elliptical densities is examined in detail, establishing connections with existing similar work. The final part of the paper specializes further to a form of multivariate skew t-density. Likelihood inference for this distribution is examined, and it is illustrated with numerical examples.
Functional Quasi-Likelihood Regression Models with Smooth Random Effects
Authors: Chiou Jeng-Min , Müller Hans-Georg , Wang Jane-Ling 
Published: December 2004

SummaryWe propose a class of semiparametric functional regression models to describe the influence of vector-valued covariates on a sample of response curves. Each observed curve is viewed as the realization of a random process, composed of an overall mean function and random components. The finite dimensional covariates influence the random components of the eigenfunction expansion through single-index models that include unknown smooth link and variance functions. The parametric components of the single-index models are estimated via quasi-score estimating equations with link and variance functions being estimated nonparametrically. We obtain several basic asymptotic results. The functional regression models proposed are illustrated with the analysis of a data set consisting of egg laying curves for 1000 female Mediterranean fruit-flies (medflies).
Data Tilting for Time Series
Authors: Hall Peter , Yao Qiwei 
Published: December 2004

SummaryWe develop a general methodology for tilting time series data. Attention is focused on a large class of regression problems, where errors are expressed through autoregressive processes. The class has a range of important applications and in the context of our work may be used to illustrate the application of tilting methods to interval estimation in regression, robust statistical inference and estimation subject to constraints. The method can be viewed as ‘empirical likelihood with nuisance parameters’.
The poetry of nationalism*
Authors: Aberbach David 
Published: December 2004

Abstract.The poetry of nationalism has roots in ancient literature, particularly the Hebrew Bible, but is mostly a product of nationalism since the French Revolution. Many national poets are politically active and serve in government. Asserting artistic individuality, they express national individuality, though nationalism can also suppress creativity. Calling for moral regeneration, poets inspire their people with memories of heroism, real or imagined, and with myths unique to the nation. Their poetry often springs from defeat but anticipates national liberation and independence. Yet there is also a dark side to some national poets, particularly in their glorification of violence and lust for revenge against oppressors. National poetry changed after the failed revolutions of 1848–9. National poets were less inclined to believe in liberal ideals and progress toward universal goals and there was greater disillusionment and ambiguity toward the national role. World War I severely limited the militarist tendency in national poetry.
Prefrontal cortex: Links between low frequency delta EEG in sleep and neuropsychological performance in healthy, older people
Authors: Anderson Clare , Horne James A. 
Published: December 2004

AbstractLow frequency (<1 Hz) delta EEG in sleep is of increasing interest as it indicates cortical reorganization, especially in the prefrontal cortex (PFC). Other research shows that delta power in sleep is positively linked to waking cerebral metabolic rate. Such findings suggest that<1 Hz activity may reflect waking performance at neuropsychological tests specific to the PFC. We investigated this unexplored area. Sleep EEGs (Fp1–F3, Fp2–F4, O1–P3, O2–P4) were recorded in 24 healthy 61–75‐year‐olds. We found significant associations between 0.5–1.0 Hz power from the left frontal EEG channel, in the first non‐REM period, and performance at tasks more specific to the left PFC (e.g., nonverbal planning and verbal fluency). This association was absent from the posterior channels. Neither age nor response times were confounding factors. This potential sleep EEG marker for PFC neuropsychological function in healthy, older people also points to further uses of the sleep EEG in understanding the role of sleep.
Representation of the standard: Stimulus context effects on the process generating the mismatch negativity component of event‐related brain potentials
Authors: Sussman Elyse , Sheridan Karen , Kreuzer Judith , Winkler István 
Published: December 2004

AbstractIn the auditory oddball paradigm, the frequent occurrence of a sound (the “standard”) forms the basis of deviance detection. The incoming sounds are compared with the cortical representation of the standard and those sounds that do not match it elicit the mismatch negativity (MMN) event‐related brain potential. Here we address the issue of whether the relative probability of the sounds in a sequence was a critical factor influencing which sounds would be represented as standards in the deviant comparison process. One frequent (F1) and two infrequent (D1 and D2) sounds that differed only in duration were presented in a sequence. D1 occurred proportionally as frequently with respect to D2 as F1 occurred with respect to D1. If the proportional relationship of sounds were critical then D1 could serve as a “standard” to D2 and thus D2 should elicit two MMNs. However, D2 elicited MMN only with respect to F1. This result as well as those obtained in two control conditions suggests that “standards” are not established on the basis of relative probability; they emerge as a result of global characteristics, the longer‐term context, of the sound sequence.
Effects of cycling exercise on the soleus H‐reflex and state anxiety among men with low or high trait anxiety
Authors: Motl Robert W. , O'connor Patrick J. , Dishman Rod K. 
Published: December 2004

AbstractThe present study examined the effects of low‐ and high‐intensity cycling exercise on the H‐reflex and state anxiety among men having low (n=20) or high (n=20) trait anxiety. Participants completed measures of state anxiety and underwent elicitation and recording of the H‐reflex in the soleus muscle before and 10 min after three 20‐min conditions: (1) quiet rest, (2) cycling at 40% V̇O2peak, and (3) cycling at 70% V̇O2peak. We found that (1) exercise, but not quiet rest, resulted in a reduction of the H‐reflex; the magnitude of the reduction did not differ between men having low or high trait anxiety; (2) exercise and quiet rest resulted in similar reductions of state anxiety, and the magnitude of the reductions was larger for men having high trait anxiety than low trait anxiety; and (3) reductions of the H‐reflex were unrelated to reductions of self‐reported state anxiety across all three conditions. Contrary to prior opinion, the postexercise reduction in the H‐reflex reported by previous researchers and in the present study appears to be unrelated to self‐reported anxiety after exercise.
Electrophysiological evidence for altered early cerebral somatosensory signal processing in schizophrenia
Authors: Waberski Till D. , Norra Christine , Kawohl Wolfram , Thyerlei Dinah , Hock Dorothee , Klostermann Fabian , Curio Gabriel , Buchner Helmut , Hoff Paul , Gobbelé René 
Published: December 2004

AbstractVarious studies have indicated an impairment of sensory signal processing in schizophrenic patients. Anatomical and functional imaging studies have indicated morphological and metabolic abnormalities in the thalamus in schizophrenia. Other results give evidence for an additional role of cortical dysfunction in sensory processing in schizophrenia. Advanced analysis of human median nerve somatosensory evoked potentials (SEPs) reveals a brief oscillatory burst of low‐amplitude and high‐frequency activity (∼600 Hz), the so‐called high frequency oscillations (HFOs). The present study explores the behavior of HFOs in a cohort of schizophrenic patients in comparison to a group of controls. HFOs in the group of patients appeared with a delayed latency. In the low‐frequency part of the SEPs an increase in amplitude was found. These results are interpreted to reflect a lack of somatosensory inhibition in the somatosensory pathway, either at a thalamic or a cortical level.
Menstrual cycle phase effects on prepulse inhibition of acoustic startle
Authors: Jovanovic Tanja , Szilagyi Sandor , Chakravorty Subhajit , Fiallos Ana M. , Lewison Barbara J. , Parwani Arti , Schwartz Marion P. , Gonzenbach Stephen , Rotrosen John P. , Duncan Erica J. 
Published: December 2004

AbstractPrepulse inhibition (PPI) represents an attenuation of the startle reflex following the presentation of a weak prepulse at brief intervals prior to the startle eliciting pulse. It has been shown that increases in striatal dopamine levels decrease PPI; because dopamine release is sensitive to estrogen, it is likely that PPI varies across the menstrual cycle. Cross‐sectional studies looking at estrogen effects suggest that this may be true. In this study, we compare effects of menstrual phase on PPI in a between‐group design (men, follicular phase women, and luteal phase women) as well as a within‐subjects design (women across the two phases). The study found a between‐group as well as a within‐subjects effect of phase on PPI. PPI in follicular phase women did not differ significantly from PPI in men. However, PPI was reduced in luteal women compared to follicular women. These data provide evidence that ovarian hormones affect sensorimotor gating.