989 resultados para orthogonal projections


Relevância:

10.00% 10.00%

Publicador:

Resumo:

Hispanics are a large and growing part of the United States workforce. Projections of the U.S. Census Bureau (2001) state that, by the year 2050, Hispanics will account for 25% of the population. For the Midwest in particular, the Hispanic population is expected to increase 35% by the year 2025. The construction industry is expected to experience a greater percentage increase of its Hispanic population, due to the labor-intensive nature of the industry. This study addresses the expected increase of Hispanic workers in the construction industry by testing the best approaches for delivering training to construction crews with Hispanic workers as well as American supervisors and laborers in the state of Iowa. The research methodology consisted of assessing the effects on communication, safety, work environment, and productivity as a result of the integration training. Results show that integration on-site training decreases workers’ desire to move and increases quality of work and productivity. Most importantly, experimental design was used to show the increasing levels of direct construction communication due to the Toolbox Integration Course for Hispanic Workers and American Supervisors (TICHA) designed as part of this project. This study recommends the creation of a quasi-governmental or association program that can offer continuous research and training that can benefit the construction industry as well as society as a whole. The industry involvement in this process is crucial for contractors. Not only do contractors benefit from reduced insurance premiums when workers act safely, but workers with better communication skills are more productive.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

We tested for antigen recognition and T cell receptor (TCR)-ligand binding 12 peptide derivative variants on seven H-2Kd-restricted cytotoxic T lymphocytes (CTL) clones specific for a bifunctional photoreactive derivative of the Plasmodium berghei circumsporozoite peptide 252-260 (SYIPSAEKI). The derivative contained iodo-4-azidosalicylic acid in place of PbCS S-252 and 4-azidobenzoic acid on PbCS K-259. Selective photoactivation of the N-terminal photoreactive group allowed crosslinking to Kd molecules and photoactivation of the orthogonal group to TCR. TCR photoaffinity labeling with covalent Kd-peptide derivative complexes allowed direct assessment of TCR-ligand binding on living CTL. In most cases (over 80%) cytotoxicity (chromium release) and TCR-ligand binding differed by less than fivefold. The exceptions included (a) partial TCR agonists (8 cases), for which antigen recognition was five-tenfold less efficient than TCR-ligand binding, (b) TCR antagonists (2 cases), which were not recognized and capable of inhibiting recognition of the wild-type conjugate, (c) heteroclitic agonists (2 cases), for which antigen recognition was more efficient than TCR-ligand binding, and (d) one partial TCR agonist, which activated only Fas (C1)95), but not perforin/granzyme-mediated cytotoxicity. There was no correlation between these divergences and the avidity of TCR-ligand binding, indicating that other factors than binding avidity determine the nature of the CTL response. An unexpected and novel finding was that CD8-dependent clones clearly incline more to TCR antagonism than CD8-independent ones. As there was no correlation between CD8 dependence and the avidity of TCR-ligand binding, the possibility is suggested that CD8 plays a critical role in aberrant CTL function.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Abstract The amygdala is a group of nuclei in the temporal lobe of the brain that plays a crucial role in anxiety and fear behavior. Sensory information converges in the basolateral and lateral nuclei of the amygdala, which have been the first regions in the brain where the acquisition of new (fear) memories has been associated with long term changes in synaptic transmission. These nuclei, in turn, project to the central nucleus of the amygdala. The central amygdala, through its extensive projections to numerous nuclei in the midbrain and brainstem, plays a pivotal role in the orchestration of the rapid autonomic and endocrine fear responses. In the central amygdala a large number of neuropeptides and receptors is expressed, among which high levels of vasopressin and oxytocin receptors. Local injections of these peptides into the amygdala modulate several aspects of the autonomic fear reaction. Interestingly, their effects are opposing: vasopressin tends to enhance the fear reactions, whereas oxytocin has anxiolytic effects. In order to investigate the neurophysiological mechanisms that could underlie this opposing modulation of the fear behavior, we studied the effects of vasopressin and oxytocin on the neuronal activity in an acute brain slice preparation of the rat central amygdala. We first assessed the effects of vasopressin and oxytocin on the spontaneous activity of central amygdala neurons. Extracellular single unit recordings revealed two major populations of neurons: a majority of neurons was excited by vasopressin and inhibited by oxytocin, whereas other neurons were only excited by oxytocin receptor activation. The inhibitory effect of oxytocin could be reduced by the block of GABAergic transmission, whereas the excitatory effects of vasopressin and oxytocin were not affected. In a second step we identified the cellular mechanisms for the excitatory effects of both peptides as well as the morphological and biochemical mechanisms underlying the opposing effects, by using sharp electrode recordings together with intracellular labelings. We revealed that oxytocin-excited neurons are localized in the lateral part (CeL) whereas vasopressin excited cells are found in the medial part of the central amygdala (CeM). The tracing of the neuronal morphology showed that the axon collaterals of the oxytocin-excited neurons project from the CeL, far into the CeM. Combined immunohistochemical stainings indicated that these projections are GABAergic. In the third set of experiments we investigated the synaptic interactions between the two identified cell populations. Whole-cell patch-clamp recordings in the CeM revealed that the inhibitory effect of oxytocin was caused by the massive increase of inhibitory GABAergic currents, which was induced by the activation of CeL neurons. Finally, the effects of vasopressin and oxytocin on evoked activity were investigated. We found on the one hand, that the probability of evoking action potentials in the CeM by stimulating the basolateral amygdala afferents was enhanced under vasopressin, whereas it decreased under oxytocin. On the other hand, the impact of cortical afferents stimulation on the CeL neurons was enhanced by oxytocin application. Taken together, these findings have allowed us to develop a model, in which the opposing behavioral effects of vasopressin and oxytocin are caused by a selective activation of two distinct populations of neurons in the GABAergic network of the central amygdala. Our model could help to develop new anxiolytic treatments, which modulate simultaneously both receptor systems. By acting on a GABAergic network, such treatments can further be tuned by combinations with classical benzodiazepines. Résumé: L'amygdale est un groupe de noyaux cérébraux localisés dans le lobe temporal. Elle joue un rôle essentiel dans les comportements liés à la peur et l'anxiété. L'information issue des aires sensorielles converge vers les noyaux amygdaliens latéraux et basolatéraux, qui sont les projections vers différents noyaux du tronc cérébral et de l'hypothalamus, joue un rôle clef premières régions dans lesquelles il a été démontré que l'acquisition d'une nouvelle mémoire (de peur) était associée à des changements à long terme de la transmission synaptique. Ces noyaux envoient leurs projections sur l'amygdale centrale, qui à travers ses propres dans l'orchestration des réponses autonomes et endocrines de peur. Le contrôle de l'activité neuronale dans l'amygdale centrale module fortement la réaction de peur. Ainsi, un grand nombre de neuropeptides sont spécifiquement exprimés dans l'amygdale centrale et un bon nombre d'entre eux interfère dans la réaction de peur et d'anxiété. Chez les rats, une forte concentration de récepteurs à l'ocytocine et à la vasopressine est exprimée dans le noyau central, et l'injection de ces peptides dans l'amygdale influence différents aspects de la réaction viscérale associée à la peur. Il est intéressant de constater que ces peptides exercent des effets opposés. Ainsi, la vasopressine augmente la réaction de peur alors que l'ocytocine a un effet anxiolytique. Afin d'investiguer les mécanismes neurophysiologiques responsables de ces effets opposés, nous avons étudié l'effet de la vasopressine et de l'ocytocine sur l'activité neuronale de préparations de tranches de cerveau de rats contenant entre autres de l'amygdale centrale. Tout d'abord, notre intérêt s'est porté sur les effets de ces deux neuropeptides sur l'activité spontanée dans l'amygdale centrale. Des enregistrements extracellulaires ont révélé différentes populations de neurones ; une majorité était excitée par la vasopressine et inhibée par l'ocytocine ; d'autres étaient seulement excités par l'activation du récepteur à l'ocytocine. L'effet inhibiteur de l'ocytocine a pu être réduit par l'inhibition de la transmission GABAergique, alors que ses effets excitateurs n'étaient pas affectés. Dans un deuxième temps, nous avons identifié les mécanismes cellulaires responsables de l'effet excitateur de ces deux peptides et analysé les caractéristiques morphologiques et biochimiques des neurones affectés. Des enregistrements intracellulaires ont permis de localiser les neurones excités par l'ocytocine dans la partie latérale de l'amygdale centrale (CeL), et ceux excités par la vasopressine dans sa partie médiale (CeM). Le traçage morphologique des neurones a révélé que les collatérales axonales des cellules excitées par l'ocytocine projetaient du CeL loin dans le CeM. De plus, des colorations immuno-histochimiques ont révélé que ces projections étaient GABAergiques. Dans un troisième temps, nous avons étudié les interactions synaptiques entre ces deux populations de cellules. Les enregistrements en whole-cell patch-clamp dans le CeM ont démontré que les effets inhibiteurs de l'ocytocine résultaient de l'augmentation massive des courants GABAergique résultant de l'activation des neurones dans le CeL. Finalement, les effets de l'ocytocine et de la vasopressine sur l'activité évoquée ont été étudiés. Nous avons pu montrer que la probabilité d'évoquer un potentiel d'action dans le CeM, par stimulation de l'amygdale basolatérale, était augmentée sous l'effet de la vasopressine et diminuée sous l'action de l'ocytocine. Par contre, l'impact de la stimulation des afférences corticales sur les neurones du CeL était augmenté par l'application de l'ocytocine. L'ensemble de ces résultats nous a permis de développer un modèle dans lequel les effets comportementaux opposés de la vasopressine et de l'ocytocine sont causés par une activation sélective des deux différentes populations de neurones dans un réseau GABAergique. Un tel modèle pourrait mener au développement de nouveaux traitements anxiolytiques en modulant l'activité des deux récepteurs simultanément. En agissant sur un réseau GABAergique, les effets d'un tel traitement pourraient être rendus encore plus sélectifs en association avec des benzodiazépines classiques.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Using one male-inherited, one female-inherited and eight biparentally inherited markers, we investigate the population genetic structure of the Valais shrew (Sorex antinorii) in the Swiss Alps. Bayesian analysis on autosomal microsatellites suggests a clear genetic differentiation between two groups of populations. This geographically based structure is consistent with two separate postglacial recolonization routes of the species into Switzerland from Italian refugia after the last Pleistocene glaciations. Sex-specific markers also confirm genetic structuring among western and eastern areas, since very few haplotypes for either Y chromosome or mtDNA genome are shared between the two regions. Overall, these results suggest that two already well-differentiated genetic lineages colonized the Swiss Alps and came into secondary contact in the Rhône Valley. Low level of admixture between the two lineages is likely explained by the mountainous landscape structure of lateral valleys orthogonal to the main Rhône valley.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

We compute the exact vacuum expectation value of 1/2 BPS circular Wilson loops of TeX = 4 U(N) super Yang-Mills in arbitrary irreducible representations. By localization arguments, the computation reduces to evaluating certain integrals in a Gaussian matrix model, which we do using the method of orthogonal polynomials. Our results are particularly simple for Wilson loops in antisymmetric representations; in this case, we observe that the final answers admit an expansion where the coefficients are positive integers, and can be written in terms of sums over skew Young diagrams. As an application of our results, we use them to discuss the exact Bremsstrahlung functions associated to the corresponding heavy probes.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

A transitory projection from primary and secondary auditory areas to the contralateral and ipsilateral areas 17 and 18 exists in newborn kittens. Distinct neuronal populations project to ipsilateral areas 17-18, contralateral areas 17-18 and contralateral auditory cortex; they are at different depth in layers II, III, and IV. By postnatal day 38 the auditory to visual projections have been lost, apparently by elimination of axons rather than by neuronal death. While it was previously reported that the elimination of transitory axons is responsible for focusing the origin of callosal connections to restricted portions of sensory areas it now appears that similar events play a more general role in the organization of cortico-cortical networks. Indeed, the elimination of juvenile projections is largely responsible for determining which areas will be connected in the adult.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

A major problem with holographic optical tweezers (HOTs) is their incompatibility with laser-based position detection methods, such as back-focal-plane interferometry (BFPI). The alternatives generally used with HOTs, like high-speed video tracking, do not offer the same spatial and temporal bandwidths. This has limited the use of this technique in precise quantitative experiments. In this paper, we present an optical trap design that combines digital holography and back-focal-plane displacement detection. We show that, with a particularly simple setup, it is possible to generate a set of multiple holographic traps and an additional static non-holographic trap with orthogonal polarizations and that they can be, therefore, easily separated for measuring positions and forces with the high positional and temporal resolutions of laser-based detection. We prove that measurements from both polarizations contain less than 1% crosstalk and that traps in our setup are harmonic within the typical range. We further tested the instrument in a DNA stretching experiment and we discuss an interesting property of this configuration: the small drift of the differential signal between traps.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

In this work, a new one-class classification ensemble strategy called approximate polytope ensemble is presented. The main contribution of the paper is threefold. First, the geometrical concept of convex hull is used to define the boundary of the target class defining the problem. Expansions and contractions of this geometrical structure are introduced in order to avoid over-fitting. Second, the decision whether a point belongs to the convex hull model in high dimensional spaces is approximated by means of random projections and an ensemble decision process. Finally, a tiling strategy is proposed in order to model non-convex structures. Experimental results show that the proposed strategy is significantly better than state of the art one-class classification methods on over 200 datasets.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Purpose : To assess time trends of testicular cancer (TC) mortality in Spain for period 1985-2019 for age groups 15-74 years old through a Bayesian age-period-cohort (APC) analysis. Methods: A Bayesian age-drift model has been fitted to describe trends. Projections for 2005-2019 have been calculated by means of an autoregressive APC model. Prior precision for these parameters has been selected through evaluation of an adaptive precision parameter and 95% credible intervals (95% CRI) have been obtained for each model parameter. Results: A decrease of -2.41% (95% CRI: -3.65%; -1.13%) per year has been found for TC mortality rates in age groups 15-74 during 1985-2004, whereas mortality showed a lower annual decrease when data was restricted to age groups 15-54 (-1.18%; 95% CRI: -2.60%; -0.31%). During 2005-2019 is expected a decrease of TC mortality of 2.30% per year for men younger than 35, whereas a leveling off for TC mortality rates is expected for men older than 35. Conclusions: A Bayesian approach should be recommended to describe and project time trends for those diseases with low number of cases. Through this model it has been assessed that management of TC and advances in therapy led to decreasing trend of TC mortality during the period 1985-2004, whereas a leveling off for these trends can be considered during 2005-2019 among men older than 35.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Purpose : To assess time trends of testicular cancer (TC) mortality in Spain for period 1985-2019 for age groups 15-74 years old through a Bayesian age-period-cohort (APC) analysis. Methods: A Bayesian age-drift model has been fitted to describe trends. Projections for 2005-2019 have been calculated by means of an autoregressive APC model. Prior precision for these parameters has been selected through evaluation of an adaptive precision parameter and 95% credible intervals (95% CRI) have been obtained for each model parameter. Results: A decrease of -2.41% (95% CRI: -3.65%; -1.13%) per year has been found for TC mortality rates in age groups 15-74 during 1985-2004, whereas mortality showed a lower annual decrease when data was restricted to age groups 15-54 (-1.18%; 95% CRI: -2.60%; -0.31%). During 2005-2019 is expected a decrease of TC mortality of 2.30% per year for men younger than 35, whereas a leveling off for TC mortality rates is expected for men older than 35. Conclusions: A Bayesian approach should be recommended to describe and project time trends for those diseases with low number of cases. Through this model it has been assessed that management of TC and advances in therapy led to decreasing trend of TC mortality during the period 1985-2004, whereas a leveling off for these trends can be considered during 2005-2019 among men older than 35.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Purpose : To assess time trends of testicular cancer (TC) mortality in Spain for period 1985-2019 for age groups 15-74 years old through a Bayesian age-period-cohort (APC) analysis. Methods: A Bayesian age-drift model has been fitted to describe trends. Projections for 2005-2019 have been calculated by means of an autoregressive APC model. Prior precision for these parameters has been selected through evaluation of an adaptive precision parameter and 95% credible intervals (95% CRI) have been obtained for each model parameter. Results: A decrease of -2.41% (95% CRI: -3.65%; -1.13%) per year has been found for TC mortality rates in age groups 15-74 during 1985-2004, whereas mortality showed a lower annual decrease when data was restricted to age groups 15-54 (-1.18%; 95% CRI: -2.60%; -0.31%). During 2005-2019 is expected a decrease of TC mortality of 2.30% per year for men younger than 35, whereas a leveling off for TC mortality rates is expected for men older than 35. Conclusions: A Bayesian approach should be recommended to describe and project time trends for those diseases with low number of cases. Through this model it has been assessed that management of TC and advances in therapy led to decreasing trend of TC mortality during the period 1985-2004, whereas a leveling off for these trends can be considered during 2005-2019 among men older than 35.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Purpose : To assess time trends of testicular cancer (TC) mortality in Spain for period 1985-2019 for age groups 15-74 years old through a Bayesian age-period-cohort (APC) analysis. Methods: A Bayesian age-drift model has been fitted to describe trends. Projections for 2005-2019 have been calculated by means of an autoregressive APC model. Prior precision for these parameters has been selected through evaluation of an adaptive precision parameter and 95% credible intervals (95% CRI) have been obtained for each model parameter. Results: A decrease of -2.41% (95% CRI: -3.65%; -1.13%) per year has been found for TC mortality rates in age groups 15-74 during 1985-2004, whereas mortality showed a lower annual decrease when data was restricted to age groups 15-54 (-1.18%; 95% CRI: -2.60%; -0.31%). During 2005-2019 is expected a decrease of TC mortality of 2.30% per year for men younger than 35, whereas a leveling off for TC mortality rates is expected for men older than 35. Conclusions: A Bayesian approach should be recommended to describe and project time trends for those diseases with low number of cases. Through this model it has been assessed that management of TC and advances in therapy led to decreasing trend of TC mortality during the period 1985-2004, whereas a leveling off for these trends can be considered during 2005-2019 among men older than 35.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

PURPOSE: To implement real-time myocardial strain-encoding (SENC) imaging in combination with tracking the tissue displacement in the through-plane direction. MATERIALS AND METHODS: SENC imaging was combined with the slice-following technique by implementing three-dimensional (3D) selective excitation. Certain adjustments were implemented to reduce scan time to one heartbeat. A total of 10 volunteers and five pigs were scanned on a 3T MRI scanner. Spatial modulation of magnetization (SPAMM)-tagged images were acquired on planes orthogonal to the SENC planes for comparison. Myocardial infarction (MI) was induced in two pigs and the resulting SENC images were compared to standard delayed-enhancement (DE) images. RESULTS: The strain values computed from SENC imaging with slice-following showed significant difference from those acquired without slice-following, especially during systole (P < 0.01). The strain curves computed from the SENC images with and without slice-following were similar to those computed from the orthogonal SPAMM images, with and without, respectively, tracking the tag line displacement in the strain direction. The resulting SENC images showed good agreement with the DE images in identifying MI in infarcted pigs. CONCLUSION: Correction of through-plane motion in real-time cardiac functional imaging is feasible using slice-following. The strain measurements are more accurate than conventional SENC measurements in humans and animals, as validated with conventional MRI tagging.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Using the transit pulse method, we have determined compressional wave velocities of rocks from various geological units belonging to the Penninic zone along the NFP20-West profiles of the Swiss western Alps. The velocities have been measured at confining pressures up to 400 MPa, along three orthogonal axes defined by the macrostructure of the rocks. The samples analysed show a degree of metamorphism ranging from greenschist to eclogite facies. This collection includes schists, dolomites, gneisses and ophiolitic rocks. The mean velocities range from 5.9 km/s for a quartzitic calcschist to 7.9 km/s for an eclogitic metagabbro. The velocity anisotropy is as high as 20 %. The range of acoustic impedance is wide, from 15 to 27 10(6) kg/m2s. From these measurements, normal incident reflection coefficients for likely rock assemblages within and between geological units were estimated in order to interpret zone of the strong reflections recorded along the seismic profiles. Reflection coefficients as high as 0.17 could be determined.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

This paper presents a Bayesian approach to the design of transmit prefiltering matrices in closed-loop schemes robust to channel estimation errors. The algorithms are derived for a multiple-input multiple-output (MIMO) orthogonal frequency division multiplexing (OFDM) system. Two different optimizationcriteria are analyzed: the minimization of the mean square error and the minimization of the bit error rate. In both cases, the transmitter design is based on the singular value decomposition (SVD) of the conditional mean of the channel response, given the channel estimate. The performance of the proposed algorithms is analyzed,and their relationship with existing algorithms is indicated. As withother previously proposed solutions, the minimum bit error rate algorithmconverges to the open-loop transmission scheme for very poor CSI estimates.