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Showing papers by "Laval University published in 2000"


Journal ArticleDOI
TL;DR: The Situational Motivation Scale (SIMS) as mentioned in this paper is designed to assess the constructs of intrinsic motivation, identified regulation, external regulation, and amotivation in field and laboratory settings.
Abstract: The purpose of the present research was to develop and validate a situational (or state) measure of motivation, the Situational Motivation Scale (SIMS) The SIMS is designed to assess the constructs of intrinsic motivation, identified regulation, external regulation, and amotivation (E L Deci & R M Ryan, 1985, 1991) in field and laboratory settings Five studies were conducted to develop and validate the SIMS Overall, results show that the SIMS is composed of 4 internally consistent factors The construct validity of the scale is also supported by correlations with other constructs as postulated by current theories Moreover, the SIMS is responsive to experimental induction as evidenced by data gathered through a laboratory study In sum, the SIMS represents a brief and versatile self-report measure of situational intrinsic motivation, identified regulation, external regulation, and amotivation

1,209 citations


Journal ArticleDOI
TL;DR: It is demonstrated here that mice lacking Ucp2 following targeted gene disruption are not obese and have a normal response to cold exposure or high-fat diet and a role for UCP2 in the limitation of ROS and macrophage-mediated immunity is indicated.
Abstract: The gene Ucp2 is a member of a family of genes found in animals and plants, encoding a protein homologous to the brown fat uncoupling protein Ucp1 (refs 1–3). As Ucp2 is widely expressed in mammalian tissues4,5, uncouples respiration6 and resides within a region of genetic linkage to obesity4, a role in energy dissipation has been proposed. We demonstrate here, however, that mice lacking Ucp2 following targeted gene disruption are not obese and have a normal response to cold exposure or high-fat diet. Expression of Ucp2 is robust in spleen, lung and isolated macrophages4,5,7, suggesting a role for Ucp2 in immunity or inflammatory responsiveness4. We investigated the response to infection with Toxoplasma gondii in Ucp2−/− mice, and found that they are completely resistant to infection, in contrast with the lethality observed in wild-type littermates. Parasitic cysts and inflammation sites in brain were significantly reduced in Ucp2−/− mice (63% decrease, P<0.04). Macrophages from Ucp2 −/− mice generated more reactive oxygen species than wild-type mice (80% increase, P<0.001) in response to T. gondii, and had a fivefold greater toxoplasmacidal activity in vitro compared with wild-type mice (P<0.001 ), which was absent in the presence of a quencher of reactive oxygen species (ROS). Our results indicate a role for Ucp2 in the limitation of ROS and macrophage-mediated immunity.

1,062 citations


Journal ArticleDOI
TL;DR: In this paper, a series of composite membranes based on sulfonated polyether ether ketone with embedded heteropolycompounds were studied and their electrochemical and thermal properties were studied, showing that an increase in degree of sulfonation and introduction of these fillers resulted in increased Tg and enhanced membrane hydrophilicity, bringing about a substantial gain in proton conductivity.

838 citations


Journal ArticleDOI
Mircea Steriade1
TL;DR: In vivo experiments using simultaneous intracellular recordings from thalamic and cortical neurons show that short-term plasticity processes occur after prolonged and rhythmic spike-bursts fired by thalamo- neocortical neurons during slow-wave sleep oscillations.

767 citations


Journal ArticleDOI
01 Jul 2000
TL;DR: Data collected indicate that subjective norms, attitude, and beliefs concerning the consequences of online shopping have significant effects on consumers' intentions to buy online and provide strong support for the positive effects of personal innovativeness on attitude and intentions to shop online.
Abstract: The objective of this study is to investigate the factors affecting online shopping. A model explaining the impact of different factors on online shopping intentions and behavior is developed based on the theory of planned behavior. The model is then tested empirically in a longitudinal study with two surveys. Data collected from 705 consumers indicate that subjective norms, attitude, and beliefs concerning the consequences of online shopping have significant effects on consumers' intentions to buy online. Behavioral control and intentions significantly influenced online shopping behavior. The results also provide strong support for the positive effects of personal innovativeness on attitude and intentions to shop online. The implications of the findings for theory and practice are discussed.

722 citations


Journal ArticleDOI
TL;DR: Oseltamivir was effective and well tolerated in the treatment of natural influenza infection in adults and was associated with higher symptom scores, less viral shedding, and improved health, activity, and sleep quality.

721 citations


Journal ArticleDOI
TL;DR: This article examined the variable use of inflection in adult second language (L2) acquisition and found that learners sometimes have a problem with realization of surface morphology, such that they resort to non-finite forms.
Abstract: In this article, two accounts of the variable use of inflection in adult second language (L2) acquisition are examined. The Missing Surface Inflection Hypothesis (MSIH) proposes that L2 learners have unconscious knowledge of the functional projections and features underlying tense and agreement. However, learners sometimes have a problem with realization of surface morphology, such that they resort to non-finite forms (e.g. Haznedar and Schwartz, 1997; Prevost and White, 1999). The Impaired Representation Hypothesis (IRH) claims that L2 inflection is essentially impaired, due to lack of functional categories, features or feature strength (e.g. Eubank, 1993/94; Meisel, 1997). These views make different predictions for adult L2 acquisition. Spontaneous production data from two adult learners of French and two adult learners of German are examined. The data show that finite forms do not occur in non-finite contexts, that learners exhibit syntactic reflexes of finiteness and that inflected forms largely show ...

715 citations


Journal ArticleDOI
TL;DR: The authors derived the asymptotic sampling distribution of various estimators frequently used to order distributions in terms of poverty, welfare, and inequality, including estimators of most of the poverty indices currently in use, as well as estimators used to infer stochastic dominance of any order.
Abstract: We derive the asymptotic sampling distribution of various estimators frequently used to order distributions in terms of poverty, welfare, and inequality. This includes estimators of most of the poverty indices currently in use, as well as estimators of the curves used to infer stochastic dominance of any order. These curves can be used to determine whether poverty, inequality, or social welfare is greater in one distribution than in another for general classes of indices and for ranges of possible poverty lines. We also derive the sampling distribution of the maximal poverty lines up to which we may confidently assert that poverty is greater in one distribution than in another. The sampling distribution of convenient dual estimators for the measurement of poverty is also established. The statistical results are established for deterministic or stochastic poverty lines as well as for paired or independent samples of incomes. Our results are briefly illustrated using data for four countries drawn from the Luxembourg Income Study data bases.

695 citations


Journal ArticleDOI
TL;DR: An in vivo preparation has been developed to study the mechanisms underlying spontaneous sleep oscillations in anesthetized cats and an analytical model of the cortical network accurately predicted the scaling observed in simulations and from recordings in cortical slabs of increasing size.
Abstract: An in vivo preparation has been developed to study the mechanisms underlying spontaneous sleep oscillations. Dual and triple simultaneous intracellular recordings were made from neurons in small isolated cortical slabs (10 mm x 6 mm) in anesthetized cats. Spontaneously occurring slow sleep oscillations, present in the adjacent intact cortex, were absent in small slabs. However, the isolated slabs displayed brief active periods separated by long periods of silence, up to 60 s in duration. During these silent periods, 60% of neurons showed non-linear amplification of low-amplitude depolarizing activity. Nearly 40% of the cells, twice as many as in intact cortex, were classified as intrinsically bursting. In cortical network models based on Hodgkin-Huxley-like neurons, the summation of simulated spontaneous miniature excitatory postsynaptic potentials was sufficient to activate a persistent sodium current, initiating action potentials in single neurons that then spread through the network. Consistent with this model, enlarging the isolated cortical territory to an isolated gyrus (30 mm x 20 mm) increased the probability of initiating large-scale activity. In these larger territories, both the frequency and regularity of the slow oscillation approached that generated in intact cortex. The frequency of active periods in an analytical model of the cortical network accurately predicted the scaling observed in simulations and from recordings in cortical slabs of increasing size.

667 citations


Journal ArticleDOI
TL;DR: The pilot study provides evidence for the efficacy of a task-related circuit class at improving locomotor function in chronic stroke.

607 citations


Journal ArticleDOI
TL;DR: Successful semen cryopreservation enhances the advantages of AI over natural breeding, as long-term storage facilitates semen transport over distances, permits the quarantine of semen, and enables extended use of superior germplasm, even after the sire's death.
Abstract: The genetic improvement of agriculturally important species and disease control are of fundamental importance to the success of a sustainable agri-food industry. In this sense, artificial insemination (AI) is arguably the most important tool contributing to the advancement of modern animal production. Through AI, 1 ejaculate from a genetically superior male can be used to impregnate multiple females to maximize the distribution of agriculturally favorable genes. As well, AI eliminates physical contact between animals, thus limiting the spread of sexually transmitted diseases. Successful semen cryopreservation enhances these advantages of AI over natural breeding. Long-term storage facilitates semen transport over distances, permits the quarantine of semen, and enables extended use of superior germplasm, even after the sire’s death. For agriculturally important animals, semen cryopreservation is an established industry worldwide, particularly for dairy cattle. Genome resource banking to preserve the biodiversity of endangered species or valuable transgenic lines also would benefit from sperm cryopreservation. For many mammals; however, effective semen cryopreservation is not a reality because a large number of sperm are apparently infertile following freezing and thawing. Compared to fresh, 8 times more cryopreserved bovine sperm were required to achieve equivalent fertilization rates in vivo (Shannon and Vishwanath, 1995). Although AI in pigs with fresh, cooled semen is increasingly popular, the fertility of cryopreserved semen remains about half that of fresh semen (Crabo, 1991). Following either transuterine or oviductal insemination of superovulated ewes, conception rates and percentage of fer-

Journal ArticleDOI
TL;DR: An update on the concept of aortic prosthesis-patient mismatch is presented and the present knowledge with regard to its impact on hemodynamic status, functional capacity, morbidity and mortality is reviewed.

Journal ArticleDOI
TL;DR: The results show that the proposed early stopped training approach (STA) is effective for improving prediction accuracy and offers an alternative when dynamic adaptive forecasting is desired.

Journal ArticleDOI
TL;DR: The results suggest that the plant defense enzymes could be stimulated in cucumber roots which have been colonized by non-pathogenic rhizobacteria or in a compatible interaction between cucumber and P. aphanidermatum.

Journal ArticleDOI
TL;DR: It is found that bovine spermatozoa are poorly adapted to metabolize the toxic hydrogen peroxide and the involvement of an oxidative stress during a freeze/thaw cycle is consistent with the hypothesis that ROS generated during such a cycle are detrimental to sperm function.
Abstract: Growing evidence suggests that the generation of reactive oxygen species (ROS) and their detoxification by antioxidants plays a very important role in fertility. However, the relationship between the level of antioxidants in spermatozoa and the decreased fecundity following a freeze/thaw cycle remains poorly understood. We assessed the activities of antioxidant enzymes such as catalase, glutathione peroxidase (GPx), superoxide dismutase (SOD), and levels of reduced/oxidized glutathione (GSH/GSSG) in bovine semen. Sperm cells were isolated using a Percoll gradient to avoid contamination from seminal plasma, cellular debris, and other cell types. We found that bovine spermatozoa are poorly adapted to metabolize the toxic hydrogen peroxide (H(2)O(2)). Indeed, very low levels of GPx and an absence of catalase were observed. We also studied the effect of freezing and thawing bovine spermatozoa in a egg yolk-Tris-glycerol extender (EYTG). Cryopreservation significantly reduced sperm GSH levels by 78% and SOD activity by 50%. We also investigated whether the decrease in GSH level could be linked to oxidative metabolism and found that a greater reduction in intracellular GSH level occurred when fresh sperm cells were incubated in EYTG for 6 hr at 38.5 degrees C under aerobic conditions than when incubated under restricted oxygen availability. Our results strongly suggest the involvement of an oxidative stress during a freeze/thaw cycle and are consistent with the hypothesis that ROS generated during such a cycle are detrimental to sperm function.

Journal ArticleDOI
TL;DR: Evaluated antimicrobial films, designed to slowly release bacterial inhibitors, to improve the preservation of vacuum-packaged processed meats during refrigerated storage found strongest inhibition was observed on drier surfaces (bologna), onto which acid release was slower, and with films containing cinnamaldehyde, as a result of its greater antimicrobial activity under these conditions.

Journal ArticleDOI
TL;DR: A nearly perfect correlation between genotypic and phenotypic analysis for most of these 394 strains found the usefulness of DNA-based assays for the detection of antibiotic resistance genes associated with staphylococcal infections.
Abstract: Clinical isolates of Staphylococcus aureus (a total of 206) and S. epidermidis (a total of 188) from various countries were tested with multiplex PCR assays to detect clinically relevant antibiotic resistance genes associated with staphylococci. The targeted genes are implicated in resistance to oxacillin (mecA), gentamicin ?aac(6')-aph(2"), and erythromycin (ermA, ermB, ermC, and msrA). We found a nearly perfect correlation between genotypic and phenotypic analysis for most of these 394 strains, showing the following correlations: 98% for oxacillin resistance, 100% for gentamicin resistance, and 98.5% for erythromycin resistance. The discrepant results were (i) eight strains found to be positive by PCR for mecA or ermC but susceptible to the corresponding antibiotic based on disk diffusion and (ii) six strains of S. aureus found to be negative by PCR for mecA or for the four erythromycin resistance genes targeted but resistant to the corresponding antibiotic. In order to demonstrate in vitro that the eight susceptible strains harboring the resistance gene may become resistant, we subcultured the susceptible strains on media with increasing gradients of the antibiotic. We were able to select cells demonstrating a resistant phenotype for all of these eight strains carrying the resistance gene based on disk diffusion and MIC determinations. The four oxacillin-resistant strains negative for mecA were PCR positive for blaZ and had the phenotype of beta-lactamase hyperproducers, which could explain their borderline oxacillin resistance phenotype. The erythromycin resistance for the two strains found to be negative by PCR is probably associated with a novel mechanism. This study reiterates the usefulness of DNA-based assays for the detection of antibiotic resistance genes associated with staphylococcal infections.

Journal ArticleDOI
01 Mar 2000-Sleep
TL;DR: An adequate evaluation of persistent insomnia requires detailed historical information as well as medical, psychological and psychiatric assessment, and use of a classification system for sleep disorders and familiarity with major diagnostic groups will facilitate the clinician's evaluation and treatment.
Abstract: Insomnia is a condition which affects millions of individuals, giving rise to emotional distress, daytime fatigue, and loss of productivity. Despite its prevalence, it has received scant clinical attention. An adequate evaluation of persistent insomnia requires detailed historical information as well as medical, psychological and psychiatric assessment. Use of a classification system for sleep disorders and familiarity with major diagnostic groups will facilitate the clinician's evaluation and treatment. Thorough assessment also requires attention to the unique aspects of presentation and specific set of etiologies which are associated with particular age groups.

Journal ArticleDOI
TL;DR: The results indicate that participants whose level of intolerance of uncertainty was increased showed a higher level of worry, compared to participants whoselevel of intolerance was decreased, which is coherent with the theoretical model of worry and GAD, which stipulates thatolerance of uncertainty plays a key role in the acquisition and maintenance of excessive worry.

Journal ArticleDOI
TL;DR: The present findings indicate a cell-specific localization of ERalpha, ERbeta and AR in reproductive tissues in rats of both sexes, which contribute to a better understanding of the respective role of these steroids in reproduction function.
Abstract: There is now evidence that oestrogens and androgens can influence male and female reproductive systems. In order to accurately identify the sites of action of oestrogens and androgens, we have proceeded to the histological localization of the two oestrogen receptor (ER) subtypes, ERalpha and ERbeta, and the androgen receptor (AR) in the reproductive tissues of adult rats of both sexes. AR was detected by immunocytochemistry, while ERalpha and ERbeta were localized by both immunocytochemistry and in situ hybridization. In the pituitary gland of animals of both sexes, ERalpha was found in the majority of nuclei of secretory cells in the anterior pituitary. The intermediate and posterior lobes did not show any staining. ERbeta was not found to be expressed in any of the pituitary lobes. Using AR antibodies, nuclear staining was detected in about 50% of secretory cells of the anterior lobe, the intermediate and posterior lobes being completely unstained. In the testis, ERalpha was localized in nuclei of Leydig cells as well as in round spermatocytes and spermatids, while ERbeta could only be detected in Sertoli cell nuclei. AR immunoreactivity was found in nuclei of Sertoli, peritubular myoid and Leydig cells. In the prostate, ERbeta was observed in epithelial cells of tubulo-alveoli, while the stroma was unlabelled. ERalpha was not found to be expressed in any prostate cells. In the prostate, AR was detected in nuclei of epithelial, stromal and endothelial cells. In seminal vesicles, staining of ERalpha was found in nuclei of epithelial and stromal cells. Similar findings were observed using AR antibodies. While ERbeta mRNA could not be detected by in situ hybridization, weak staining for ERbeta was localized in epithelial cells of seminal vesicles. In the ovary, both ERalpha and ERbeta were found to be expressed. ERbeta mRNA was found in granulosa cells of growing follicles, while ERalpha was present in theca cells, interstitial gland cells and germinal epithelium. AR immunoreactivity was detected in granulosa cell nuclei in growing follicles and also in scattered interstitial cells. In the oviduct and uterus, ERalpha was observed in nuclei of epithelial cells as well as of stromal and muscle cells. Similarly, AR immunoreactivity was present in nuclei of epithelial cells, stromal and muscle cells in both the oviduct and uterus. ERbeta was not detected in the oviduct and uterus. The present findings indicate a cell-specific localization of ERalpha, ERbeta and AR in reproductive tissues in rats of both sexes. By establishing the precise sites of action of oestrogens and androgens they contribute to a better understanding of the respective role of these steroids in reproduction function.

Journal ArticleDOI
TL;DR: It is shown that phosphorylated dimers of HSP27 interact with Daxx, a mediator of Fas-induced apoptosis, preventing the interaction of DAXx with both Ask1 and Fas and blocking DaxX-mediated apoptosis.
Abstract: Heat shock protein 27 (HSP27) confers cellular protection against a variety of cytotoxic stresses and also against physiological stresses associated with growth arrest or receptor-mediated apoptosis. Phosphorylation modulates the activity of HSP27 by causing a major change in the supramolecular organization of the protein, which shifts from oligomers to dimers. Here we show that phosphorylated dimers of HSP27 interact with Daxx, a mediator of Fas-induced apoptosis, preventing the interaction of Daxx with both Ask1 and Fas and blocking Daxx-mediated apoptosis. No such inhibition was observed with an HSP27 phosphorylation mutant that is only expressed as oligomers or when apoptosis was induced by transfection of a Daxx mutant lacking its HSP27 binding domain. HSP27 expression had no effect on Fas-induced FADD- and caspase-dependent apoptosis. However, HSP27 blocked Fas-induced translocation of Daxx from the nucleus to the cytoplasm and Fas-induced Daxx- and Ask1-dependent apoptosis. The observations revealed a new level of regulation of the Fas pathway and suggest a mechanism for the phosphorylation-dependent protective function of HSP27 during stress and differentiation.

Journal ArticleDOI
TL;DR: The hypotheses that the initial occurrence of clinically significant depression, MDD, results from either biochemical changes directly due to type 2 diabetes or its treatment or from the psychosocial demands imposed by the illness or the treatment do not seem to be supported.
Abstract: OBJECTIVE: To review the support for two hypotheses concerning the interrelationship between depression and diabetes and to identify areas in which more research is needed. RESEARCH DESIGN AND METHODS: A review was conducted using primarily electronic databases. Articles relating to diabetes and depressive symptomatology, depressive disorder, and dysthymic disorder were selected. The study focuses mainly on adults with diabetes. RESULTS: The initial onset of major depressive disorder (MDD) seems to be independent of the onset of type 2 diabetes, but results remain equivocal for type 1 diabetes. However, in both type 1 and type 2 diabetes, diabetes-related psychological and physiological processes may be involved in the higher recurrence and longer duration of MDD and depressive symptomatology CONCLUSIONS: The hypotheses that the initial occurrence of clinically significant depression, MDD, results from either biochemical changes directly due to type 2 diabetes or its treatment or from the psychosocial demands imposed by the illness or its treatment do not seem to be supported. MDD in diabetic individuals represents a multidetermined phenomenon resulting from interactions between biologic and psychosocial factors. This interaction may increase the probability of developing type 2 diabetes in otherwise healthy individuals.

Journal ArticleDOI
TL;DR: In this article, the critical intensity inside plasma filaments generated in air by high-power, ultra-short laser pulses is estimated analytically and compared to recent experimental data.
Abstract: The critical intensity inside plasma filaments generated in air by high-power, ultra-short laser pulses is estimated analytically and compared to recent experimental data. The result, Icrit≈4×1013 W/cm2, is highly relevant for atmospheric applications.

Journal ArticleDOI
TL;DR: The results suggest that the higher plasma HDL cholesterol levels and the generally more cardioprotective plasma lipoprotein profile found in abdominally obese black versus white individuals are explained, at least to a certain extent, by a lower visceral AT deposition and a higher plasma LPL activity in black individuals.
Abstract: Abdominal obesity is associated with numerous metabolic alterations, such as hypertriglyceridemia and low levels of high density lipoprotein (HDL) cholesterol. However, compared with abdominally obese white individuals, abdominally obese black individuals have been characterized by higher plasma HDL cholesterol levels, suggesting that the impact of abdominal fat accumulation on the lipoprotein-lipid profile may differ among ethnic groups. Therefore, we have compared the associations between body fatness, visceral adipose tissue (AT) accumulation, and metabolic risk variables in a sample of 247 white men and 240 white women versus a sample of 93 black men and 143 black women. Although no difference in mean total body fatness was found between the 2 race groups, white men had higher levels of visceral AT than did black men (P<0.001). Despite the fact that black women had a greater body fat content than did white women, black women had levels of visceral AT that were similar to those of white women, suggesting a lower susceptibility to visceral obesity in black women. This lower accumulation of visceral AT in blacks was accompanied by significantly reduced apolipoprotein B concentrations and ratios of total cholesterol to HDL cholesterol as well as higher plasma HDL cholesterol levels (P<0.05) compared with those values in whites. Irrespective of sex, higher postheparin plasma hepatic lipase (HL) and lower lipoprotein lipase (LPL) activities were found in whites, resulting in an HL/LPL ratio that was twice as high in whites as in blacks (P<0.005). Although differences in lipoprotein-lipid levels were noted between whites and blacks, results from multiple regression analyses revealed that after control for morphometric and metabolic variables of the study (body fat mass, visceral AT, LPL, HL, and age), ethnicity had, per se, only a minor contribution to the variance in plasma lipoprotein levels. Thus, our results suggest that the higher plasma HDL cholesterol levels and the generally more cardioprotective plasma lipoprotein profile found in abdominally obese black versus white individuals are explained, at least to a certain extent, by a lower visceral AT deposition and a higher plasma LPL activity in black individuals.

Journal ArticleDOI
TL;DR: In this paper, a survey of the central 700 arcmin2 region of the ρ Ophiuchi molecular cloud at 850 μm using the Submillimeter Common-User Bolometer Array (SCUBA) on the James Clerk Maxwell Telescope is presented.
Abstract: We present results from a survey of the central 700 arcmin2 region of the ρ Ophiuchi molecular cloud at 850 μm using the Submillimeter Common-User Bolometer Array (SCUBA) on the James Clerk Maxwell Telescope. Using the clump-finding procedure developed by Williams et al., we identify 55 independent objects and compute size, flux, and degree of central concentration. Comparison with isothermal, pressure-confined, self-gravitating Bonnor-Ebert spheres implies that the clumps have internal temperatures of 10-30 K and surface pressures P/k = 106-7 K cm-3, consistent with the expected average pressure in the ρ Ophiuchi central region, P/k ~ 2 × 107 K cm-3. The clump masses span 0.02-6.3 M☉ assuming a dust temperature Td ~ 20 K and a dust emissivity κ850 = 0.01 cm2 g-1. The distribution of clump masses is well characterized by a broken power law, N(M) ∝ M-α, with α = 1.0-1.5 for M > 0.6 M☉ and α = 0.5 for M ≤ 0.6 M☉, although significant incompleteness may affect the slope at the lower mass end. This mass function is in general agreement with the ρ Ophiuchi clump mass function derived at 1.3 mm by Motte et al. The two-point correlation function of the clump separations is measured and reveals clustering on size scales r < 3 × 104 AU with a radial power-law exponent γ = 0.75.

Journal ArticleDOI
Antoine Bellemare1, M. Karasek1, Martin Rochette1, S. LRochelle, Michel Tetu1 
TL;DR: In this paper, a room temperature multifrequency erbium-doped fiber (EDF) laser anchored on the ITU frequency grid and using frequency periodic filters is presented.
Abstract: Room temperature multifrequency erbium-doped fiber (EDF) lasers anchored on the ITU frequency grid and using frequency periodic filters are presented. The multifrequency operation is demonstrated both theoretically and experimentally by adding a frequency shifter in the ring cavity to prevent steady-state laser operation and single-frequency oscillation.

Journal ArticleDOI
TL;DR: In this article, the kinematic characteristics of a three degree-of-freedom (dof) parallel mechanism are studied. Butler et al. present an architecture of the mechanism consisting of a mobile platform attached to a base through three identical prismatic-revolute-spherical jointed serial linkages.
Abstract: A study of the kinematic characteristics of a three degree-of-freedom (dof) parallel mechanism is presented. The architecture of the mechanism is comprised of a mobile platform attached to a base through three identical prismatic-revolute-spherical jointed serial linkages. The prismatic joints are considered to be actuated. These prismatic actuators lie on a common plane and have radial directions of action. The mechanism's inverse displacement solution is obtained. Since the mechanism has only 3 dof, constraint equations describing the inter-relationship between the six motion coordinates are derived. These constraints allow the definition of parasitic motions, i.e., motions in the three unspecified motion coordinates. Architecture optimization of the device is undertaken demonstrating that specific values of design variables allow minimization of parasitic motion.

Journal ArticleDOI
TL;DR: Pertussis in secondary case patients was less severe than in index case patients but presented with classic symptoms, and the burden of disease appears to increase with age, with smoking, and with asthma.
Abstract: The effect of age on the clinical presentation of pertussis was assessed in 664 adolescent and adult cases. Complications were more frequent in adults than in adolescents (28% vs. 16%). Pneumonia occurred in 2% of patients /=50 years old. Duration of cough, risk of sinusitis, and number of nights with disturbed sleep increased with smoking and asthma. The secondary attack rate in other household members >/=12 years was 11%. Pertussis in secondary case patients was less severe than in index case patients but presented with classic symptoms. The main source of infection in adolescents was schoolmates or friends; in adults it was workplace or their children. Teachers and health care workers had a greater risk of pertussis than did the general population. The burden of disease appears to increase with age, with smoking, and with asthma.

Patent
08 Sep 2000
TL;DR: In this paper, the authors proposed a method for estimating systolic and mean pulmonary artery pressures of a patient, comprising the steps of (a) producing an electric signal xs(t) representative of heart sounds of the patient; (b) extracting second heart sound S2(t), from the signal produced in step (a); (c) extracting pulmonary and aortic components P2t and A2t from S2t; (d) extracting a signal representative of mean cardiac interval; (e) correlating the pulmonary and anaphyric components P
Abstract: The method of estimating systolic and mean pulmonary artery pressures of a patient, comprising the steps of (a) producing an electric signal xs(t) representative of heart sounds of the patient; (b) extracting second heart sound S2(t) from the signal produced in step (a); (c) extracting pulmonary and aortic components P2(t) and A2(t) from S2(t); (d) extracting a signal representative of mean cardiac interval; (e) correlating the pulmonary and aortic components P2(t) and A2(t) to obtain a cross correlation function; (f) measuring a splitting interval of the cross correlation function obtained in step (e); (g) producing a normalized splitting interval; and (h) estimating the systolic and mean pulmonary artery pressures by means of predetermined regressive functions The present invention also relates to an apparatus for estimating systolic and mean pulmonary artery pressures of a patient

Journal ArticleDOI
TL;DR: It is concluded that VEGFR2 mediates the physiological effect of VEGF on cell migration and that two independent pathways downstream of V EGFR2 regulate actin-based motility.