Search

We give an explicit Dirichlet series for the generating function of the discriminants of quartic dihedral extensions of ℚ. From this series we deduce an asymptotic formula for the number of isomorphism classes of such quartic extensions with discriminant up to a given bound. On the other hand, by using essentially classical results of genus theory combined with elementary analytical methods such as the method of the hyperbola, we show how to compute exactly this number up to quite large bounds, and we give a table of selected values.

Let k be a quadratic field. We give an explicit formula for the Dirichlet series enumerating cubic fields whose quadratic resolvent field is isomorphic to k. Our work is a sequel to previous work of Cohen and Morra, where such formulas are proved in a more general setting, in terms of sums over characters of certain groups related to ray class groups. In the present paper we carry the analysis further and prove explicit formulas for these Dirichlet series over Q. In a companion paper we do the same for quartic fields having a given cubic resolvent. As an application (not present in the initial version), we compute tables of the number of S_3-sextic fields E with |Disc(E)| < X, for X ranging up to 10^23. An accompanying PARI/GP implementation is available from the second author's website., 16 pages, submitted. Revised version: includes counts of S_3-sextic fields

The neuropsychological profile of a child with a Landau-Kleffner syndrome is presented here. The observed cognitive difficulties included verbal short-term memory and seemed partially compensated for when the experimental assessments bypassed the auditory channel. This case study is especially challenging since the child, whose phonological skills were quite efficient and who exhibited a dichotic listening unilateral extinction, had developed average reading and spelling abilities. The fact that B.E.'s performance on memory tasks was quite poor when the stimuli were presented auditorily and more efficient when the stimuli were presented visually, strongly suggests that the observed memory impairment was due to a deficit at the level of cortical auditory processing. B.E.'s phonological skills were efficient, suggesting a neuropsychological dissociation between phonological ability and auditory processing. The fact that B.E. dramatically recovered language and easily acquired reading and spelling accounts for the hypothesis that compensatory strategies allowed him to develop phonological skills from predominantly visual input.

International audience; We study several methods for the numerical computation of Petersson scalar products, and in particular we prove a generalization of Haberland's formula to any subgroup of finite index G of Gamma = PSL_2 (Z), which gives a fast method to compute these scalar products when a Hecke eigenbasis is not necessarily available.

Aluminum (Al)-containing calcium-deficient carbonated hydroxyapatites were produced by a precipita- tion method from aqueous solution with carbonate (0-6.1%) and aluminum (0.1-0.5%) concentrations close to those found in biological materials. Two series of apatites were prepared: one at pH 7.0 and another at pH 9.0. High- resolution electron microscopy has shown that many of them possess structural defects such as screw dislocations, grain boundaries, and central defects. Samples with high carbonate content and high water and high Al 3+ content had a high amount of structural defects. Accordingly, a sample (7Al1) with a relatively high carbonate content (6.1%) and a sample (7Al6) without carbonate but with a relatively high water (2.0 mol) and Al 3+ content (0.39%) presented the high- est amount of structural defects, 54% and 47%, respectively. A sample (7Al13) with a low level of crystalline water (1 mol) and low carbonate (2.5%) showed a small amount of defects. The presence of water associated with Al 3+ induced a high number of crystals having a central defect with a great similarity to the so-called water layer of octacalcium phosphate (OCP). Observed images of all these crystals have shown good correspondence with the computer-simulated image based on the crystal structure of hydroxyapatite, in- dicating that the addition of Al 3+ and carbonate does not perturbe the apatitic structure. © 2000 John Wiley & Sons

Resume Nous donnons une formule asymptotique pour le nombre d'extensions relatives cycliques de degre premier d'un corps de nombres.

Le but de cet article est d'expliquer comment calculer exactement le nombre de classes d'isomorphismes d'extensions abeliennes de Q en degre inferieur ou egal a 4 et de discriminant majore par une borne donnee. On parvient par exemple a calculer le nombre de corps cubiques cycliques de discriminant inferieur ou egal a 10 37 .

Cochlear implants apparently restore the inner ear functions and increase the acoustic consciousness of pre- and postlingually deaf children. However, not all deaf individuals benefit equally from the implantation of this electronic device and several variables appear to critically affect post-implant linguistic performance. We review the scientific literature on particular aspects of speech and language development following cochlear implantation. The available data show great variability in post-implant linguistic improvement: for some, a cochlear implant allows the full development of linguistic competence and provides marked benefits in a wide range of psychological and social abilities, whereas others remain language-delayed or develop a functional but imperfect command of language. The degree and patterns of linguistic development are greatly influenced by the characteristics of the population studied, including the age at which deafness occurred and the length of the auditory deprivation period.

A linguistic analysis in low-risk preterm (PT) children was conducted to determine whether the acquisition of complex aspects of the lexicon, such as verbs, was influenced by their premature birth status and whether sociocultural factors played a modulating role in this aspect of cognitive development. Fifty-one PT children, distributed in three birthweight groups — extremely low (780–1200 g), very low (1201–1500 g) and low (1501–2210 g) — were evaluated at 42 months and 60 months of age to assess their production of main, auxiliary and non-finite verb types and tokens relative to that of two control groups of full-term children matched for age and socioeconomic level. The children's verb lexicon was collected during a 20-min controlled play context. Analyses of transcript data revealed first that the effect of sociocultural variables was independent of birth status or age. Further analyses revealed significant differences, indicating a marked increase in both verb type and token usage in the control children, whereas verb production in the three groups of PT children remained generally poorer. The data suggest that impaired language development is a cognitive consequence of prematurity independently of birthweight.

Language production involves complex yet productively varying motor behavior. Rule-governed combinations yield a finite set of formational units combined in an infinite number of ways. The creativity of language ensures that no particular articulation will be highly automatized. Linguistic articulation is highly complex and varied. As such, it differs from the other more automatized motor behaviors typically studied such as learned movements in apraxia studies or repetitive behavior as occurs in walking or other everyday activities. Language also strives to maintain a balance between ease of articulation and ease of perception, while maintaining linguistically relevant distinctions. We report here a number of studies on the articulatory consequences of Parkinson's disease (PD) in the spoken and signed modalities. Our goal is to highlight the commonalities and distinctions between the two modalities of speech and sign that will allow us to better understand the impingements of PD on language production in general.

We describe the computation of extended tables of degree 8 fields with a quartic subfield, using class field theory. In particular we find the minimum discriminants for all signatures and for all the possible Galois groups. We also discuss some phenomena and statistics discovered while making the tables, such as the occurrence of 11 non-isomorphic number fields having the same discriminant, or several pairs of non-isomorphic number fields having the same Dedekind zeta function.

We use the algorithmic computation of exact sequences of Abelian groups to compute the complete structure of ( Z K / m ) ∗ (\mathbb {Z}_{K}/\mathfrak {m})^{*} for an ideal m \mathfrak {m} of a number field K K , as well as ray class groups of number fields, and conductors and discriminants of the corresponding Abelian extensions. As an application we give several number fields with discriminants less than previously known ones.

In this study we investigated lateralized control of speech during the intracarotid amobarbital procedure. Vowel segments were extracted from recordings made during two separate amobarbital procedures and involving two patients. Subjects were right-handed, presented with focal left mesial temporal epileptogenic foci. Age of onset of seizure disorders was 1.5 years for one subject and 16 years for the other. Recorded pre- and postinjection speech samples were digitized. Analyses were conducted on formants 1 and 2 (F1, F2) measures to determine the extent of formant fluctuation in the time course of the IAP. Preliminary results showed, for these two cases, that the left hemisphere is involved in the control of both F1and F2and the right in the control of F2only. The data reveal the potential of coupling the IAP procedure and the acoustical analysis of speech in the study of cerebral control of speech.

We present a preliminary investigation of macroscopic polarimetric imaging of uterine cervix. Orthogonal state contrast (OSC) images of healthy and anomalous cervices have been taken in vivo at 550 nm. Four ex vivo cervix samples have been studied in full Muller polarimetry, at 550 nm and 700 nm, and characterized in detail by standard pathology. One sample was totally healthy, another one carried CIN lesions at very early stage (CIN1) in its visible exocervical region, while for the other two samples more advanced (CIN3) lesions were present, together with visible glandular epithelium (ectropion). Significant birefringence has been observed in the healthy regions of all six samples, both in vivo and ex vivo. Standard treatments of the Mueller images of the ex vivo samples allowed to quantify both retardation and depolarization. Retardation reached 60° in healthy regions, and disappeared in the anomalous regions of the other three ex vivo samples. The depolarization power was largest in healthy regions, and lower in CINs and ectropion. Possible origins of the observed effects are briefly discussed.

We correct some too optimistic predictions in an earlier paper of ours.

It has previously been shown that impairment of postural stability is a side effect of typical antipsychotic drugs, which are largely administered to control psychosis and behavioral symptoms in elderly patients. Surprisingly, no study has yet addressed this problem with second-generation antipsychotics. The objective of this study was to determine the extent to which risperidone at low doses altered balance control in healthy participants. Twelve healthy young adults received, following a randomized double-blind crossover design, a single oral dose of placebo, 1 and 3 mg of risperidone on separate days at least 14 days apart. Evaluation of extrapyramidal symptoms using the Extrapyramidal Symptom Rating Scale-abbreviated scoring form (ESRS-A) and measures of postural sway using a force platform were assessed over 9 h following drug ingestion. There is a significant increase in the postural stability item of the ESRS-A parkinsonism subscale at 3 and 6 h following 3 mg of risperidone only when compared to placebo. With regard to balance control, body sway measures were increased at 1 mg of risperidone but more pronounced at 3 mg. The peak effects were observed at 3 h after administration of the drug and had not completely returned to baseline after 9 h. Risperidone administered at low doses did not elicit clinically detectable EPS but had significant effects on balance control. A dose–response effect on impairment of balance was observed that followed the expected time course of the drug pharmacokinetics. These results are likely to apply to older or demented individuals who have pre-existing balance control deficit.

Tactile working memory was found to be more developed in completely blind (congenital and acquired) than in semi-sighted subjects, indicating that experience plays a crucial role in shaping working memory. A model of working memory, adapted from the classical model proposed by Baddeley and Hitch (1) and Baddeley (2), is presented where the connection strengths of a highly cross-modal network are altered through experience.

As an iatrogenic movement disorder, tardive dyskinesia (TD) offers a unique opportunity to study brain-behavior relationships. The authors provide a brief overview of TD and discuss its association to cognitive dysfunction. It is argued that, given the complexity of the variables involved in the study of TD, there is pressing need for greater applications of neuropsychological research paradigms to help elucidate this disorder.

Tardive dyskinesia (TD) has been associated with cognitive deficits, especially in older psychiatric patients an neuroleptic medication. This study investigated the relationship between presence of TD, organic brain dysfunction (OBD), and cognitive deficits in young psychiatric outpatients maintained on minimal doses of oral neuroleptics, with anticholinergics prescribed only on an as-needed basis. Sixty-four patients, aged 20-39 years, were evaluated for the presence of abnormal movements, localizing and nonlocalizing physical signs, and deficits in memory, ability to shift, and sustained attention. Sixteen patients showed definite signs of TD. Significant associations were found between TD and OBD, and between cognitive deficits and OBD, but not between TD and cognitive deficits. Significant regression predictors of TD were the interaction between OBD and previous dystonia, as well as duration of neuroleptic treatment. These findings suggest that some potential risk factors for TD already identified in the literature also apply to younger patients with relatively shorter exposure to neuroleptics. However, the results indicate that the relationship between movement disorders and cognitive deficits may be more apparent in older patients.

Given a number field $k$ and a quadratic extension $K_2$, we give an explicit asymptotic formula for the number of isomorphism classes of cubic extensions of $k$ whose Galois closure contains $K_2$ as quadratic subextension, ordered by the norm of their relative discriminant ideal. The main tool is Kummer theory. We also study in detail the error term of the asymptotics and show that it is $O(X^{\alpha})$, for an explicit $\alpha, Comment: 19 pages

International audience; Motor actions and action verbs activate similar cortical brain regions. A functional interference can be taken as evidence that there is a parallel treatment of these two types of information and would argue for the biological grounding of language in action. A novel approach examining the relationship between language and grip force is presented. With eyes closed and arm extended, subjects listened to words relating (verbs) or not relating (nouns) to a manual action while holding a cylinder with an integrated force sensor. There was a change in grip force when subjects heard verbs that related to manual action. Grip force increased from about 100 ms following the verb presentation, peaked at 380 ms and fell abruptly after 400 ms, signalling a possible inhibition of the motor simulation evoked by these words. These observations reveal the intimate relationship that exists between language and grasp and show that it is possible to elucidate online new aspects of sensorimotor interaction.

Depression in Idiopathic Parkinson's disease (IPD) is frequent, difficult to recognize, under managed and has a profound impact on quality of life. Current categorization of diagnosis in psychiatry poorly applies to the protean manifestations of mood disorders presented by parkinsonian patients. In this study we have chosen to dissect the state of depressive mood as assessed with the Beck Depression Inventory (BDI) at different points in time of pharmacological interventions using a dimensional approach. The 21 items of the BDI were classified in two new categories or factors: hyperkinetic and hypokinetic. The hyperkinetic factor included all items related to unbalanced intrusions of negative feelings and ideas, as well as to behavioral hyperactivity. The hypokinetic factor included all items related to loss of drive for appetitive behaviors and loss of mental and physical energy. The objectives were to (1) compare different pharmacological treatments on the two-factor approach in PD depression, (2) determine the influence of levodopa therapy on the two-factor approach, and (3) explore the two-factor approach in placebo conditions. Three sets of analyses using the hypo/hyperkinetic dichotomy favour a neurobiological dissociation of these factors in response to pharmacological intervention: symptoms of the hyperkinetic factor are responsive to serotonergic drugs while those of the hypokinetic one are not and may even show deterioration under SSRIs. In contrast, the hypokinetic factor is responsive to dopaminergic drugs and may show deterioration under serotonergic drugs. Furthermore, the two factors seem to transiently dissociate on placebo intervention aiming at correcting either mood or motor status. The dimensional approach to depression symptomatology may thus be of heuristic value in probing aminergic modulation of mood in IPD and establishing new correlations between affective and motor symptoms.

We examined auditory perception in Williams syndrome by investigating strategies used in organizing sound patterns into coherent units. In Experiment 1, we investigated the streaming of sound sequences into perceptual units, on the basis of pitch cues, in a group of children and adults with Williams syndrome compared to typical controls. We showed that individuals with Williams syndrome were sensitive to the same pitch cues as typical children and adults when streaming these patterns. In Experiment 2, we evaluated differences in reliance on pitch and contour cues in unfamiliar melody perception in a group of adults with Williams syndrome relative to typical control children and adults. Unlike controls who demonstrated greater proficiency when contour cues were available, adults with Williams syndrome showed no such advantage.

International audience; In this expository paper, we show how to use in practice 3-descent with a 3-isogeny to find an estimate for the rank of an elliptic curve having a rational 3-torsion subgroup, and we also give a geometric interpretation of these computations.

International audience; In this study, we examined the influence of child gender and sociocultural (SCL) factors in languageproduction. Subjects were French Parisian children in nine age groups (24, 27, 30, 33, 36, 39, 42, 45and 48 months). A total of 316 language samples were recorded during a 20-min standardized playsession. Measures of grammatical and lexical development included Mean Length of Utterance(MLU) and word type and token—specifically, grammatical words such as determiners, prepositionsand pronouns as well as verbs. ANOVAs revealed strong influences of SCL, with children from highSCL families showing more complex lexical productions and a higher rate of development. Theseobservations suggest that amount of exposure to language accounts for this differential rate ofacquisition. Analyses also revealed a general effect of gender, showing a small advantage in languageproduction for girls over boys until 36 months of age.

La formule de Raabe classique donne la valeur de l'integrale de la fonction log gamma d'Euler sur un intervalle de longueur 1. Nous calculons des integrales p-adiques analogues pour les fonctions log gamma p-adiques de Diamond et de Morita, et nous montrons que chacune de ces fonctions est caracterisee de maniere unique par son equation fonctionnelle et sa formule de Raabe p-adique. Nous demontrons aussi une formule de type Raabe pour les fonctions zeta de Hurwitz p-adiques.

This study was concerned with the involvement of the cerebral hemispheres in the acquisition of perceptual skill with novel speech sounds. Two groups of eight subjects rated on three occasions the dissimilarity of pairs of Mandarin Chinese speech sounds varying on voicing and aspiration, presented to the left or right ear with contralateral noise. The experimental group received listening experience with long passages of Mandarin containing the target sounds. Multidimensional scaling analysis of dissimilarity ratings indicated that listening experience leads to increased perceptual differentiation of phonetic categories drawn from a language unfamiliar to the listener. This improvement occurred sooner with presentation of the target sounds to the right hemisphere than to the left if the phonological contrast was along the voicing dimension. Improvement in the perception of stimuli varying on aspiration occurred in right ear presentations only. This finding supports the position that speech perception mechanisms at the feature level may be distributed asymmetrically across the hemispheres.

We examined the development of phonological processing, naming speed, and visual attention in kindergarten and addressed the question of their contribution to reading and spelling in grade 1. Seventy five French-speaking children were administered seven tasks at the two phases of the study, and reading and spelling were assessed in grade 1. The major findings revealed that syllable awareness and visual attention were the most important predictors of early reading and spelling, and confirm the influence of naming speed and phoneme awareness on specific skills. These observations strongly suggest that written language acquisition relies on linguistic, perceptual and cognitive cross-modal skills and highlight the need for diversifying written language measures and analyzing their specific predictors. Copyright © 2006 John Wiley & Sons, Ltd.

Cumulative exposure to glucocorticoid hormones (GC) over the lifespan has been associated with cognitive impairment and may contribute to physical and cognitive degeneration in aging. The objective of the present study was to examine whether the pattern of cognitive deficits in patients with Cushing’s syndrome (CS), a disorder characterized by chronic exposure to elevated levels of glucocorticoids (GC), is similar to that observed in older individuals. Ten subjects with CS were compared to sex-, age-, and education-matched healthy controls and older subjects (age of CS subjects + 15 yr). All participants were administered tests to assess attention, visuospatial processing, learning and memory, reasoning, concept formation and verbal fluency. MANCOVAs with depression scores as covariate and polynomial contrasts revealed that the age-matched control group performed better than the CS and older subject groups in visual target detection, trail making test, stroop task, digit symbol substitution, block design, object assembly, visual reproduction, spatial memory and similarities. The CS and older subjects performed similarly on these tasks. Further, a principal component analysis revealed two significant factors, representing general cognitive function and verbal memory explaining 39.9% and 10.0% of the variance, respectively. Additional MANCOVAs with depression as a covariate revealed that CS and older control subjects showed impaired performance on general cognitive function compared to age-matched controls. These results suggest that hypersecretion of GCs has “aging-like” effects on cognitive performance in individuals with CS.

Movement formulas, engrams, kinesthetic images and internal models of the body in action are notions derived mostly from clinical observations of brain-damaged subjects. They also suggest that the prehensile geometry of an object is integrated in the neural circuits and includes the object’s graspable characteristics as well as its semantic properties. In order to determine whether there is a conjoined representation of the graspable characteristics of an object in relation to the actual grasping, it is necessary to separate the graspable (low-level) from the semantic (high-level) properties of the object. Right-handed subjects were asked to grasp and lift a smooth 300-g cylinder with one hand, before and after judging the level of difficulty of a ‘‘grasping for pouring’’ action, involving a smaller cylinder and using the opposite hand. The results showed that simulated grasps with the right hand exert a direct influence on actual motor acts with the left hand. These observations add to the evidence that there is a conjoined representation of the graspable characteristics of the object and the biomechanical constraints of the arm.

There is evidence in the literature that cognitive functions in schizophrenia (SC) may be improved by atypical neuroleptics (NLPs) in contrast to typical medication, but there is still controversy regarding this apparent superiority of atypical drugs. In this study, we assessed the differential effects of risperidone and haloperidol on verbal memory, attention, and psychiatric symptoms in SC. The performance of 28 SC participants, randomly assigned to risperidone (2–6 mg/day) or haloperidol (2–40 mg/day), was compared with that of healthy controls. The California Verbal Learning Test (CVLT), the d2 Cancellation Test, and the Positive and Negative Symptoms Scale were administered at baseline and 3, 6, and 12 months. Relative to controls, all SC participants showed markedly impaired verbal memory and processing speed at each assessment period. There was no differential effect between the two NLPs on CVLT and d2 performance. However, risperidone was more effective than haloperidol in reducing psychiatric symptoms. Improvement in symptom severity was not associated with improvement in neurocognitive performance on these specific tests. Neither conventional nor atypical neuroleptic medications improved neurocognitive functioning over a 12-month follow-up, suggesting that psychopathological improvement under risperidone is independent of cognitive function. (JINS, 2008,14, 110–118.)

One the most fundamental aspects of the human motor system is the hemispheric asymmetry seen in behavioral specialization. Hemispheric dominance can be inferred by a contralateral hand preference in grasping. Few studies have considered grasp orientation in the context of manual lateralization and none has looked at grasp orientation with natural prehension. Thirty right-handed adults performed precision grasps of a cylinder using the thumb and index fingers, and the opposition axis (OA) was defined as the line connecting these two contact points on the cylinder. Subjects made ten consecutive grasps with one hand (primary hand movements) followed by ten grasps with the other hand (trailing movements). Differences between primary and trailing grasps revealed that each hemisphere is capable of programming the orientation of the OA and that primary movements with the right hand significantly influenced OA orientation of the trailing left hand. These results extend the hemispheric dominance of the left hemisphere to the final positions of fingers during prehension.

Let $M(x)$ be the summatory function of the Möbius function and $R(x)$ be the remainder term for the number of squarefree integers up to $x$. In this paper, we prove the explicit bounds $|M(x)

The objective of this study was to describe the steps involved in establishing a morbidity/mortality review committee (MMRC) to analyze the causes of avoidable deaths or life-threatening complications and the development of plans and protocols to avoid their recurrence.The MMRC included physicians from each hospital department. Each member was responsible for organizing departmental meetings to analyze its avoidable deaths and life-threatening complications.During its meetings three times a year, the MMRC developed a method for analysis of these serious events. Each department organized 3 (range: 1-12) meetings a year and analyzed 1-3 cases at each. Over 30 months, 35,817 patients were admitted to the hospital and 341 (1%) died. The unexpected mortality rate varied by department and specialty (median: 27%, range: 6-65%). In all, 92 cases were referred to MMRC meetings (27%; range: 6-70% of hospital deaths), and 30% of them involvement nosocomial diseases. Heart disease was the primary cause of unexpected deaths.The principal improvements involved medical and surgical strategies, surgical techniques, drug prescriptions, and patient monitoring.