Étude du partage attentionnel : Analogie entre la production temporelle avec interruption et la double tâche

L’estimation temporelle de l’ordre des secondes à quelques minutes requiert des ressources attentionnelles pour l’accumulation d’information temporelle pendant l’intervalle à estimer (Brown, 2006; Buhusi & Meck, 2009; Zakay & Block, 2004). Ceci est démontré dans le paradigme de double tâche, où l’exécution d’une tâche concurrente pendant l’estimation d’un intervalle mène à un effet d’interférence, soit une distorsion de la durée perçue se traduisant par des productions temporelles plus longues et plus variables que si l’estimation de l’intervalle était effectuée seule (voir Brown, 1997; 2010). Un effet d’interférence est également observé lorsqu’une interruption est attendue pendant l’intervalle à estimer, l’allongement étant proportionnel à la durée d’attente de l’interruption (Fortin & Massé, 2000). Cet effet a mené à l’hypothèse que la production avec interruption serait sous-tendue par un mécanisme de partage attentionnel similaire à la double tâche (Fortin, 2003). Afin d’étudier cette hypothèse, deux études empiriques ont été effectuées dans des contextes expérimentaux associés respectivement à une augmentation et à une diminution de l’effet d’interférence, soit le vieillissement (Chapitre II) et l’entraînement cognitif (Chapitre III). Dans le Chapitre II, la tâche de production avec interruption est étudiée chez des participants jeunes et âgés à l’aide de la spectroscopie proche infrarouge fonctionnelle (SPIRf). Les résultats montrent que l’attente de l’interruption est associée à des coûts comportementaux et fonctionnels similaires à la double tâche. Au niveau comportemental, un allongement des productions proportionnel à la durée d’attente de l’interruption est observé chez l’ensemble des participants, mais cet effet est plus prononcé chez les participants âgés que chez les jeunes. Ce résultat est compatible avec les observations réalisées dans le paradigme de double tâche (voir Verhaegen, 2011 pour une revue). Au niveau fonctionnel, la production avec et sans interruption est associée à l’activation du cortex préfrontal droit et des régions préfrontales dorsolatérales connues pour leur rôle au niveau de l’estimation temporelle explicite (production d’intervalle) et implicite (processus préparatoires). En outre, l’attente de l’interruption est associée à l’augmentation de l’activation corticale préfrontale dans les deux hémisphères chez l’ensemble des participants, incluant le cortex ventrolatéral préfrontal associé au contrôle attentionnel dans la double tâche. Finalement, les résultats montrent que les participants âgés se caractérisent par une activation corticale bilatérale lors de la production sans et avec interruption. Dans le cadre des théories du vieillissement cognitif (Park & Reuter-Lorenz, 2009), cela suggère que l’âge est associé à un recrutement inefficace des ressources attentionnelles pour la production d’intervalle, ceci nuisant au recrutement de ressources additionnelles pour faire face aux demandes liées à l’attente de l’interruption. Dans le Chapitre III, la tâche de production avec interruption est étudiée en comparant la performance de participants assignés à l’une ou l’autre de deux conditions d’exécution extensive (cinq sessions successives) de double tâche ou de production avec interruption. Des sessions pré et post-test sont aussi effectuées afin de tester le transfert entre les conditions. Les résultats montrent un effet d’interférence et de durée d’interférence tant en production avec double tâche qu’en production avec interruption. Ces effets sont toutefois plus prononcés lors de la production avec interruption et tendent à augmenter au fil des sessions, ce qui n’est pas observé en double tâche. Cela peut être expliqué par l’influence des processus préparatoires pendant la période pré-interruption et pendant l’interruption. Finalement, les résultats ne mettent pas en évidence d’effets de transfert substantiels entre les conditions puisque les effets de la pratique concernent principalement la préparation temporelle, un processus spécifique à la production avec interruption. Par la convergence que permet l’utilisation d’un même paradigme avec des méthodologies distinctes, ces travaux approfondissent la connaissance des mécanismes attentionnels associés à l’estimation temporelle et plus spécifiquement à la production avec interruption. Les résultats supportent l’hypothèse d’un partage attentionnel induit par l’attente de l’interruption. Les ressources seraient partagées entre les processus d’estimation temporelle explicite et implicite, une distinction importante récemment mise de l’avant dans la recherche sur l’estimation du temps (Coull, Davranche, Nazarian & Vidal, 2013). L’implication de processus dépendant des ressources attentionnelles communes pour le traitement de l’information temporelle peut rendre compte de l’effet d’interférence robuste et systématique observé dans la tâche de production avec interruption.

X-Linked Retinitis Pigmentosa 2 Is a Novel Maternal-Effect Gene Required for Left-Right Asymmetry in Zebrafish

Retinitis pigmentosa 2 (RP2) gene is responsible for up to 20% of X-linked retinitis pigmentosa, a severe heterogeneous genetic disorder resulting in progressive retinal degeneration in humans. In vertebrates, several bodies of evidence have clearly established the role of Rp2 protein in cilia genesis and/or function. Unexpectedly, some observations in zebrafish have suggested the oocyte-predominant expression of the rp2 gene, a typical feature of maternal-effect genes. In the present study, we investigate the maternal inheritance of rp2 gene products in zebrafish eggs in order to address whether rp2 could be a novel maternal-effect gene required for normal development. Although both rp2 mRNA and corresponding protein are expressed during oogenesis, rp2 mRNA is maternally inherited, in contrast to Rp2 protein. A knockdown of the protein transcribed from both rp2 maternal and zygotic mRNA results in delayed epiboly and severe developmental defects, including eye malformations, that were not observed when only the protein from zygotic origin was knocked down. Moreover, the knockdown of maternal and zygotic Rp2 revealed a high incidence of left-right asymmetry establishment defects compared to only zygotic knockdown. Here we show that rp2 is a novel maternal-effect gene exclusively expressed in oocytes within the zebrafish ovary and demonstrate that maternal rp2 mRNA is essential for successful embryonic development and thus contributes to egg developmental competence. Our observations also reveal that Rp2 protein translated from maternal mRNA is important to allow normal heart loop formation, thus providing evidence of a direct maternal contribution to left-right asymmetry establishment.

“Saved by the Pacing Catheter”: Gigantic Right Atrial Thromboembolus as a Cause of Pulmonary Embolism

Pulmonary embolism (PE) related to the presence of right heart thromboemboli entails a higher mortality rate than PE alone. Furthermore, right heart thromboemboli are often associated with deep venous thrombosis. The most effective therapy for haemodynamically stable patients remains unknown, although recent data suggest that thrombolytic therapy is associated with a better outcome. We describe the case of an 83-year-old woman, hospitalized with PE consequent to right heart thrombus-in-transit, in whom investigation revealed a concomitant deep venous thrombosis. She required thrombolysis, given the high mortality risk that is traditionally associated with this clinical entity.

Amphetamine increases blood pressure and heart rate but has no effect on motor recovery or cerebral haemodynamics in ischaemic stroke: a randomized controlled trial (ISRCTN 36285333)

Amphetamine enhances recovery after experimental ischaemia and has shown promise in small clinical trials when combined with motor or sensory stimulation. Amphetamine, a sympathomimetic, might have haemodynamic effects in stroke patients, although limited data have been published. Subjects were recruited 3-30 days post ischaemic stroke into a phase II randomised (1:1), double blind, placebo-controlled trial. Subjects received dexamphetamine (5mg initially, then 10mg for 10 subsequent doses with 3 or 4 day separations) or placebo in addition to inpatient physiotherapy. Recovery was assessed by motor scales (Fugl-Meyer, FM), and functional scales (Barthel index, BI and modified Rankin score, mRS). Peripheral blood pressure (BP), central haemodynamics and middle cerebral artery blood flow velocity were assessed before, and 90 minutes after, the first 2 doses. 33 subjects were recruited, age 33-88 (mean 71) years, males 52%, 4-30 (median 15) days post stroke to inclusion. 16 patients were randomised to placebo and 17 amphetamine. Amphetamine did not improve motor function at 90 days; mean (standard deviation) FM 37.6 (27.6) vs. control 35.2 (27.8) (p=0.81). Functional outcome (BI, mRS) did not differ between treatment groups. Peripheral and central systolic BP, and heart rate, were 11.2 mmHg (p=0.03), 9.5 mmHg (p=0.04) and 7 beats/minute (p=0.02) higher respectively with amphetamine, compared with control. A non-significant reduction in myocardial perfusion (Buckberg Index) was seen with amphetamine. Other cardiac and cerebral haemodynamics were unaffected. Amphetamine did not improve motor impairment or function after ischaemic stroke but did significantly increase BP and heart rate without altering cerebral haemodynamics.

The study of histopathological damage in heart and bulbus arteriosus in rainbow trout

This study investigated the pathological changes of heart and bulbus artrius of rainbow trout breeders in several group of ages and density. The aim of study was to consider the process and the intensity of the heart and bulbus arteriosus damages in accordance to gender, age and stocking density of trout in three fish culture center (Zarghezel, Niyak in Haraz Region,Mazandaran and Espiran in Tabriz city environs). In field research, the all records the feed and feeding type, rate of mortality, stocking density of spawners and per spawners fishes, water chemical and physical specification was screened. Stocking density was considered as the most important stressor. 10 fish specimens from 7 weight groups (less than 90g, 90 to 300g, 300 to 500 g, 500 to 1000g, 1 to 3 kg, 3 to 5 kg, over 5 kg), totally 210 specimens were sampled and heart and bulbus arteriosus were taken. Samples were fixed in 10 % formalin and transferred to pathology laboratory of veterinary faculty of Tabriz Azad University. Histopathological slides and H&E staining were prepared from these samples. In total, 47 male and 73 female samples showed cardiovascular injury (29 cases in extensive system, 41 cases in semi intensive system, 50 cases in intensive system). The most important was damages, edema and hyperemia in spongy layer of atrium and ventricle muscles, but degeneration the muscle fibers, moderate edema , minor vascular damage. Hemorrhage as the effect of severs vascular damage, thrombus, sever inflammation, sever degeneration in muscle fiber, necrosis and fibrose were further pathological changed. The results of this study showed that the severity of damage increased by increasing the age (weight) of fishes. This situation was seen in all three culturing system (extensive system, semi intensive system, recirculation system). Histopathological changes is obviously seen in samples over 500g, therefore the damages were found to be important (P<0.05). Pathological effects and its severity in recirculation system was significantly high (P<0.05). Comparison with two other culturing system, histopathological changed in heart and bulbus arterius between male and female was significantly different.

Left Ventricle Non-Compaction Myocardium and Thrombophilia in a Pregnant Woman

Non-compaction of the ventricular myocardium (NCM) is a genetic cardiomyopathy usually due to mutationof the G4.5 gene located in the Xq28 chromosomal region. This congenital disorder is characterized by pronounced trabeculations and intertrabecular recesses resulting from abnormal embryogenesis between the fifth and eighth fetal weeks. The reported prevalence in the general population is between 0.014% and 1.3%. The classic triad of complications includes heart failure, ventricular arrhythmias and systemic embolic events, although some patients have an asymptomatic form. NCM is commonly diagnosed by echocardiography, but contrast ventriculography, CT and MRI can also be used. Here we present a case of left ventricle NCM, manifested after respiratory infection, in a pregnant patient with congenital thrombophilia and a history of myocardial infarction.

Double bass and electric bass: the case study of John Patitucci

The electric bass and double bass are two different instruments sharing a common function: they link harmony with rhythm, especially when talking about jazz music. The capacity of a bassist to fully support an ensemble is something that can be achieved individually playing electric or double bass. However there are some bassists who, despite of the technical differences between these two instruments, choose to play both. Some of these performers are true masters using and switching electric and double bass according to the different musical settings. It is possible to define similarities and differences between the electric and double bass, but is it viable to use similar approaches too? In order to investigate this field, I focus my research on one exemplar player who combines all the qualities needed to both play electric than double bass: John Patitucci, an inspiration for bassists of all generations and a musician who synthesizes all the fundamental characteristics of an ideal bass player. This dissertation is inspired by Patitucci’s example and by the urge to fill a gap in the specialized literature concerning the history and application of different left and right hand techniques on the electric and double bass. The main purpose of this study is to create the backbone of a bass program for teaching both instruments using John Patitucci as example. His technical approach on both instruments and his soloing vocabulary are points of departure of this dissertation. I begin my study with the historical origins of Patitucci’s techniques ending with the development of exercises created in order to teach his techniques and vocabulary to those who aspire to play electric and double bass; RESUMO: Baixo elétrico e contrabaixo, dois instrumentos distintos que partilham uma função comum: a possibilidade de produzir um conjunto de notas capazes de interligar uma grelha harmonia a uma base rítmica, criando uma coesão estética e musical, sobretudo na música jazz. A capacidade de um baixista de conseguir alcançar de forma eficiente esta ligação como sólido suporte para um “ensemble” musical está na base de uma sua eventual afirmação profissional. Há músicos que apesar das diferencias técnicas entre estes dois instrumentos, decidiram tocar ambos; alguns deles conseguiram destacarse, usando e trocando o baixo elétrico e o contrabaixo para servir melhor diferentes situações musicais. O contrabaixo e baixo elétrico têm características em comum mas ao mesmo tempo diferem por apresentar algumas diferenças técnica substanciais; será por isso possível abordar, explorar e aprender ambos utilizando uma mesma base metodológica? Com o intuito de explorar esta possibilidade direcionei a minha pesquisa para o estudo de um músico que no curso da sua longa carreira consegui grande destaque em quanto baixista elétrico e contrabaixista. John Patitucci é a síntese desta tipologia de músico, sendo uma fonte de inspiração para baixistas de todas as gerações. Esta dissertação é inspirada no seu exemplo e no desejo de colmatar o vazio presente na literatura musical comum aos dois instrumentos sobre a história e aplicação das técnicas da mão esquerda e direita. O foco principal é a criação de uma base sólida para o futuro desenvolvimento de um programa de ensino comum para o baixo eléctrico e o contrabaixo, utilizando o vocabulário técnico e improvisativo de Patitucci como ponto de partida. A dissertação aborda as origens históricas das técnicas utilizadas por Patitucci desenvolvendo, numa fase sucessiva, exercícios criados com a função de ensinar as suas técnicas aos que desejarem aprofundar a prática do baixo elétrico e do contrabaixo.

Plan of the town of Alexandria, D.C. with the environs : exhibiting the outlet of the Alexandria Canal, the shipping channel, wharves, Hunting Cr. &c. /

Relief shown by hachures. Depths shown by contours.

High-Dose Oral Ibuprofen in Treatment of Patent Ductus Arteriosus in Full-Term Neonates

Background: Patent ductus arteriosus (PDA) is an important risk for heart failure due to left to right shunt in term neonates. Objectives: In this study, we evaluated the effect of high dose ibuprofen in closure of PDA in term neonates. Patients and Methods: We used double dose ibuprofen (20 mg/kg, 10 mg/kg, and 10 mg/kg) for 3 - 30 day old term neonates with PDA who were admitted in the neonatal wards of Shiraz University of Medical Sciences. The results of this study were compared to the data of the previous study in our center which used the low dose of ibuprofen (10 mg/kg, 5 mg/kg, and 5 mg/kg). Results: 29 full term neonates received high-dose ibuprofen, in 18 neonates, PDA was closed after 4 days (62.1% versus 43.3% for the standard dose and 4.7% for the control group in the previous study) (P = 0.001). The results showed no significant correlation between the closure rate and gestational age, postnatal age, sex, and weight. In the 4th day of treatment, size of the pulmonic end of ductus arteriosus decreased from 2.09 mm to 0.77 mm compared to 1.68 mm to 0.81 mm in the standard dose of oral ibuprofen and 2.1 mm to 1.4 mm in the control group (P = 0.046). Conclusions: This study indicated that high-dose oral ibuprofen was more effective in closing or decreasing the size of PDA.

Heart dimensions may influence the occurrence of the heart rate deflection point in highly trained cyclists

To determine whether the heart rate (HR) response to exercise in 21 highly trained cyclists (mean (SD) age 25 (3) years) was related to their heart dimensions. Methods—Before performing an incremental exercise test involving a ramp protocol with workload increases of 25 W/min, each subject underwent echocardiographic evaluation of the following variables: left ventricular end diastolic internal diameter (LVIDd), left ventricular posterior wall thickness at end diastole (LVPWTd), interventricular septal wall thickness at end diastole (IVSTd), left ventricular mass index (LVMI), left atrial dimension (LAD), longitudinal left atrial (LLAD) and right atrial (LRAD) dimensions, and the ratio of early to late (E/A) diastolic flow velocity. Results—The HR response showed a de- flection point (HRd) at about 85% V~ O2MAX in 66.7% of subjects (D group; n = 14) and was linear in 33.3% (NoD group; n = 7). Several echocardiographic variables (LVMI, LAD, LLAD, LRAD) indicative of heart dimensions were similar in each group. However, mean LPWTd (p<0.01) and IVSTd (p<0.05) values were signifi- cantly higher in the D group. Finally, no significant diVerence between groups was found with respect to the E/A. The HR response is curvilinear during incremental exercise in a considerable number of highly trained endurance athletes—that is, top level cyclists. The departure of HR increase from linearity may predominantly occur in athletes with thicker heart walls.

Gender differences in right ventricular function in patients with non-ischaemic cardiomyopathy

The aim of this study is to evaluate sex-related differences in right ventricular (RV) function, assessed with cardiac magnetic resonance imaging, in patients with stable non-ischaemic dilated cardiomyopathy. Mean age was 60.9 ± 12.2 years. Men presented higher levels of haemoglobin and white blood cell counts than women, and performed better in cardiopulmonary stress testing. A total of 24 patients (12 women) presented severe left ventricular (LV) systolic dysfunction, 32 (13 female) moderate and 15 (8 women) mild LV systolic dysfunction. In the group with severe LV systolic dysfunction, average right ventricular ejection fraction (RVEF) was normal in women (52 ± 4 %), whereas it was reduced in men (39 ± 3 %) p = 0.035. Only one woman (8 %) had severe RV systolic dysfunction (RVEF < 35 %) compared with 6 men (50 %) p < 0.001. In patients with moderate and mild LV dysfunction , the mean RVEF was normal in both men and women. In the 14 healthy volunteers, the lowest value of RVEF was 48 % and mean RVEF was normal in women (56 ± 2 %) and in men (51 ±  1 %), p = 0.08. In patients with dilated cardiomyopathy, RV systolic dysfunction is found mainly in male patients with severe LV systolic dysfunction.

Vibrational spectroscopy of phthalocyanine and naphthalocyanine in sandwich-type (na)phthalocyaninato and porphyrinato rare earth complexes: Part 14. The infrared and Raman characteristics of phthalocyanine in “pinwheel-like” homoleptic bis[1,8,15,22-tetrakis(3-pentyloxy)phthalocyaninato] rare earth(III) double-decker complexes

The infrared (IR) spectroscopic data and Raman spectroscopic properties for a series of 13 “pinwheel-like” homoleptic bis(phthalocyaninato) rare earth complexes M[Pc(α-OC5H11)4]2 [M = Y and Pr–Lu except Pm; H2Pc(α-OC5H11)4 = 1,8,15,22-tetrakis(3-pentyloxy)phthalocyanine] have been collected and comparatively studied. Both the IR and Raman spectra for M[Pc(α-OC5H11)4]2 are more complicated than those of homoleptic bis(phthalocyaninato) rare earth analogues, namely M(Pc)2 and M[Pc(OC8H17)8]2, but resemble (for IR) or are a bit more complicated (for Raman) than those of heteroleptic counterparts M(Pc)[Pc(α-OC5H11)4], revealing the decreased molecular symmetry of these double-decker compounds, namely S8. Except for the obvious splitting of the isoindole breathing band at 1110–1123 cm−1, the IR spectra of M[Pc(α-OC5H11)4]2 are quite similar to those of corresponding M(Pc)[Pc(α-OC5H11)4] and therefore are similarly assigned. With laser excitation at 633 nm, Raman bands derived from isoindole ring and aza stretchings in the range of 1300–1600 cm−1 are selectively intensified. The IR spectra reveal that the frequencies of pyrrole stretching and pyrrole stretching coupled with the symmetrical CH bending of –CH3 groups are sensitive to the rare earth ionic size, while the Raman technique shows that the bands due to the isoindole stretchings and the coupled pyrrole and aza stretchings are similarly affected. Nevertheless, the phthalocyanine monoanion radical Pc′− IR marker band of bis(phthalocyaninato) complexes involving the same rare earth ion is found to shift to lower energy in the order M(Pc)2 > M(Pc)[Pc(α-OC5H11)4] > M[Pc(α-OC5H11)4]2, revealing the weakened π–π interaction between the two phthalocyanine rings in the same order.

Tuning the valence of the cerium center in (Na)phthalocyaninato and porphyrinato cerium double-deckers by changing the nature of the tetrapyrrole ligands

A series of 7 cerium double-decker complexes with various tetrapyrrole ligands including porphyrinates, phthalocyaninates, and 2,3-naphthalocyaninates have been prepared by previously described methodologies and characterized with elemental analysis and a range of spectroscopic methods. The molecular structures of two heteroleptic \[(na)phthalocyaninato](porphyrinato) complexes have also been determined by X-ray diffraction analysis which exhibit a slightly distorted square antiprismatic geometry with two domed ligands. Having a range of tetrapyrrole ligands with very different electronic properties, these compounds have been systematically investigated for the effects of ligands on the valence of the cerium center. On the basis of the spectroscopic (UV−vis, near-IR, IR, and Raman), electrochemical, and structural data of these compounds and compared with those of the other rare earth(III) counterparts reported earlier, it has been found that the cerium center adopts an intermediate valence in these complexes. It assumes a virtually trivalent state in cerium bis(tetra-tert-butylnaphthalocyaninate) as a result of the two electron rich naphthalocyaninato ligands, which facilitate the delocalization of electron from the ligands to the metal center. For the rest of the cerium double-deckers, the cerium center is predominantly tetravalent. The valences (3.59−3.68) have been quantified according to their LIII-edge X-ray absorption near-edge structure (XANES) profiles.

Raman spectroscopic characteristics of phthalocyanine and naphthalocyanine in sandwich-type phthalocyaninato and porphyrinato rare earth complexes Part 5. – Raman spectroscopic characteristics of naphthalocyanine in mixed [tetrakis(4-tert-butylphenyl)porphyrinato]-(naphthalocyaninato) rare earth double-deckers

Raman spectra were recorded in the range 400–1800 cm−1 for a series of 15 mixed \[tetrakis(4-tert-butylphenyl)porphyrinato](2,3-naphthalocyaninato) rare earth double-deckers M(TBPP)(Nc) (M = Y; La–Lu except Pm) using laser excitation at 632.8 and 785 nm. Comparisons with bis(naphthalocyaninato) rare earth counterparts reveal that the vibrations of the metallonaphthalocyanine M(Nc) fragment dominate the Raman features of M(TBPP)(Nc). When excited with radiation of 632.8 nm, the most intense vibration appears at about 1595 cm−1, due to the naphthalene stretching. These complexes exhibit the marker Raman band for Nc•− as a medium-intense band in the range 1496–1507 cm−1, attributed to the coupling of pyrrole and aza stretching, while the marker Raman band of Nc2− in intermediate-valence Ce(TBPP)(Nc) appears as a strong band at 1493 cm−1 and is due to the isoindole stretchings. By contrast, when excited with radiation of 785 nm that is in close resonance with the main Q absorption band of the naphthalocyanine ligand, the ring radial vibrations at ca 680 and 735 cm−1 for MIII(TBPP)(Nc) are selectively intensified and are the most intense bands. For the cerium double-decker, the most intense vibration also acting as the marker Raman band of Nc2− appears at 1497 cm−1 with contributions from both pyrrole CC and aza CN stretches. The same vibrational modes show weak to medium intensity scattering at 1506–1509 cm−1 for MIII(TBPP)(Nc) and this is the marker Raman band of Nc•− when thus excited. The scatterings due to the Nc breathings, ring radial vibration, aza group stretchings, naphthalene stretchings, benzoisoindole stretchings and the coupling of pyrrole CC and aza CN stretchings in MIII(TBPP)(Nc) are all slightly blue shifted along with the decrease in rare earth ionic radius, confirming the effects of increased ring–ring interactions on the Raman characteristics of naphthalocyanine in the mixed ring double-deckers.