RESUMEN
Herein, we report a catalyst-free, one-pot three-component reaction of 5-amino-2,3-dihydro-7H-thiazolo[3,2-a]pyrimidin-7-one, aromatic aldehyde, and dimedone in ethylene glycol as a green solvent at 100 °C for the easy access of hexahydro-5H-thiazolo[2',3':2,3]pyrimido[4,5-b]quinoline. Catalyst-free, green solvent, simple procedure, mild reaction conditions, easy work-up procedure, and good to excellent yields are the significant advantages of this protocol.
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QuinolinasRESUMEN
The cationic complexes of Mn(III) with the 5-Hal-sal2323 (Hal = Cl, Br) ligands and a paramagnetic doubly charged counterion [ReCl6]2- have been synthesized: [Mn(5-Cl-sal2323)]2[ReCl6] (1) and [Mn(5-Br-sal2323)]2[ReCl6] (2). Their crystal structures and magnetic properties have been studied. These isostructural two-component ionic compounds show a thermally induced spin transition at high temperature associated with the cationic subsystem and a field-induced slow magnetic relaxation of magnetization at cryogenic temperature, associated with the anionic subsystem. The compounds are the first examples of the coexistence of spin crossover and field-induced slow magnetic relaxation in the family of known [MnIII(sal2323)] cationic complexes with various counterions.
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Compuestos Organometálicos , Sales (Química) , Ligandos , Campos Magnéticos , Modelos Moleculares , Compuestos Organometálicos/químicaRESUMEN
In this paper, we report an efficient synthetic route for the 23,23-difluoro-25-hydroxyvitamin D3 (5) and its 24-hydroxylated analogues (7,8), which are candidates for the CYP24A1 main metabolites of 5. The key fragments, 23,23-difluoro-CD-ring precursors (9-11), were synthesized starting from Inhoffen-Lythgoe diol (12), and introduction of the C23 difluoro unit to α-ketoester (19) was achieved using N,N-diethylaminosulfur trifluoride (DAST). Preliminary biological evaluation revealed that 23,23-F2-25(OH)D3 (5) showed approximately eight times higher resistance to CYP24A1 metabolism and 12 times lower VDR-binding affinity than its nonfluorinated counterpart 25(OH)D3 (1).
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Calcifediol , Calcitriol , Calcifediol/metabolismo , Calcitriol/farmacología , Receptores de Calcitriol/metabolismo , Vitamina D/análogos & derivados , Vitamina D3 24-Hidroxilasa/metabolismoRESUMEN
As a fundamental part of our daily lives, visual word processing has received much attention in the psychological literature. Despite the well established advantage of perceiving letters in a word or in a pseudoword over letters alone or in random sequences using accuracy, a comparable effect using response times has been elusive. Some researchers continue to question whether the advantage due to word context is perceptual. We use the capacity coefficient, a well established, response time based measure of efficiency to provide evidence of word processing as a particularly efficient perceptual process to complement those results from the accuracy domain.
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Tiempo de Reacción/fisiología , Lectura , Percepción Visual/fisiología , Adulto , Femenino , Humanos , Masculino , Estimulación Luminosa , Adulto JovenRESUMEN
In their recent paper, Marchant, Simons, and De Fockert (2013) claimed that the ability to average between multiple items of different sizes is limited by small samples of arbitrarily attended members of a set. This claim is based on a finding that observers are good at representing the average when an ensemble includes only two sizes distributed among all items (regular sets), but their performance gets worse when the number of sizes increases with the number of items (irregular sets). We argue that an important factor not considered by Marchant et al. (2013) is the range of size variation that was much bigger in their irregular sets. We manipulated this factor across our experiments and found almost the same efficiency of averaging for both regular and irregular sets when the range was stabilized. Moreover, highly regular sets consisting only of small and large items (two-peaks distributions) were averaged with greater error than sets with small, large, and intermediate items, suggesting a segmentation threshold determining whether all variable items are perceived as a single ensemble or distinct subsets. Our results demonstrate that averaging can actually be parallel but the visual system has some difficulties with it when some items differ too much from others.
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Disposición en Psicología , Percepción del Tamaño , Femenino , Humanos , MasculinoRESUMEN
The experiment undertaken was designed to elucidate the impact of model skill level on observational learning processes. The task was bimanual circle tracing with a 90° relative phase lead of one hand over the other hand. Observer groups watched videos of either an instruction model, a discovery model, or a skilled model. The instruction and skilled model always performed the task with the same movement strategy, the right-arm traced clockwise and the left-arm counterclockwise around circle templates with the right-arm leading. The discovery model used several movement strategies (tracing-direction/hand-lead) during practice. Observation of the instruction and skilled model provided a significant benefit compared to the discovery model when performing the 90° relative phase pattern in a post-observation test. The observers of the discovery model had significant room for improvement and benefited from post-observation practice of the 90° pattern. The benefit of a model is found in the consistency with which that model uses the same movement strategy, and not within the skill level of the model. It is the consistency in strategy modeled that allows observers to develop an abstract perceptual representation of the task that can be implemented into a coordinated action. Theoretically, the results show that movement strategy information (relative motion direction, hand lead) and relative phase information can be detected through visual perception processes and be successfully mapped to outgoing motor commands within an observational learning context.
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Conducta Imitativa/fisiología , Aprendizaje/fisiología , Movimiento/fisiología , Percepción Visual/fisiología , Brazo/fisiología , Mano/fisiología , Humanos , Práctica PsicológicaRESUMEN
We examined whether body parts attached to abstract stimuli automatically force embodiment in a mental rotation task. In Experiment 1, standard cube combinations reflecting a human pose were added with (1) body parts on anatomically possible locations, (2) body parts on anatomically impossible locations, (3) colored end cubes, and (4) simple end cubes. Participants (N=30) had to decide whether two simultaneously presented stimuli, rotated in the picture plane, were identical or not. They were fastest and made less errors in the possible-body condition, but were slowest and least accurate in the impossible-body condition. A second experiment (N=32) replicated the results and ruled out that the poor performance in the impossible-body condition was due to the specific stimulus material. The findings of both experiments suggest that body parts automatically trigger embodiment, even when it is counterproductive and dramatically impairs performance, as in the impossible-body condition. It can furthermore be concluded that body parts cannot be used flexibly for spatial orientation in mental rotation tasks, compared to colored end cubes. Thus, embodiment appears to be a strong and inflexible mechanism that may, under certain conditions, even impede performance.
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Cuerpo Humano , Imaginación/fisiología , Rotación , Percepción Espacial/fisiología , Adolescente , Adulto , Femenino , Humanos , Masculino , Persona de Mediana EdadRESUMEN
The verbalization of one's thoughts has been shown to impair judgment and decision making in some cases, particularly when targets are perceptual. This finding has been attributed to the fact that non-verbal processes are sometimes difficult to verbalize, which may cause a shift in processing that is maladaptive to the task. The study shows that concurrent written explanations can also enhance judgment and decision making in certain visual choice tasks. This finding suggests that the effect of verbalization on perceptual tasks is not dependent on whether the targets of the judgment are verbal or perceptual but rather on whether there is adequate vocabulary to execute the task and whether the task benefits from a more analytic approach.
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Toma de Decisiones/fisiología , Juicio/fisiología , Habla/fisiología , Vocabulario , Adolescente , Adulto , Femenino , Humanos , Masculino , Adulto JovenRESUMEN
Embodied theories of object representation propose that the same neural networks are involved in encoding and retrieving object knowledge. In the present study, we investigated whether motor programs play a causal role in the retrieval of object names. Participants performed an object-naming task while squeezing a sponge with either their right or left hand. The objects were artifacts (e.g. hammer) or animals (e.g. giraffe) and were presented in an orientation that favored a grasp or not. We hypothesized that, if activation of motor programs is necessary to retrieve object knowledge, then concurrent motor activity would interfere with naming manipulable artifacts but not non-manipulable animals. In Experiment 1, we observed naming interference for all objects oriented towards the occupied hand. In Experiment 2, we presented the objects in more 'canonical orientations'. Participants named all objects more quickly when they were oriented towards the occupied hand. Together, these interference/facilitation effects suggest that concurrent motor activity affects naming for both categories. These results also suggest that picture-plane orientation interacts with an attentional bias that is elicited by the objects and their relationship to the occupied hand. These results may be more parsimoniously accounted for by a domain-general attentional effect, constraining the embodied theory of object representations. We suggest that researchers should scrutinize attentional accounts of other embodied cognitive effects.
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Atención/fisiología , Cognición/fisiología , Fuerza de la Mano/fisiología , Desempeño Psicomotor/fisiología , Tiempo de Reacción/fisiología , Adolescente , Adulto , Femenino , Mano/fisiología , Humanos , Masculino , Orientación/fisiología , Estimulación Luminosa , Adulto JovenRESUMEN
Human sensitivity for social cues is exquisite, as illustrated by the ease with which simplified point-light movements invoke social and emotional responses. Compared to faces, these biological motion stimuli only recently started to be used to explore questions regarding social cognition and anxiety. We presented human point-light walkers that could be perceived as facing towards or facing away from the observer, and tested whether participants with high social anxiety would perceive these bistable stimuli differently, because this type of stimuli has particular relevance for them. The results showed that observers with high social anxiety tended to see walkers as facing away more frequently than those with low social anxiety. This may mean that high socially anxious observers are biased towards the more positive perceptual alternative because they are motivated to protect themselves against threatening social experiences, but we also explore alternative explanations. The findings are in line with the evidence for a positivity bias in perception, also called wishful seeing, but in contrast with the attentional negativity bias often found in social anxiety. We discuss reasons for this divergence and possible limitations of the current study.
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Ansiedad/psicología , Percepción de Movimiento , Trastornos Fóbicos/psicología , Caminata/psicología , Adulto , Señales (Psicología) , Femenino , Humanos , Luz , MasculinoRESUMEN
Visually presented biological motion stimuli activate regions in the brain that are also related to musculo-skeletal pain. We therefore hypothesized that chronic pain impairs the perception of visually presented actions that involve body parts that hurt. In the first experiment, chronic back pain (CLBP) patients and healthy controls judged the lifted weight from point-light biological motion displays. An actor either lifted an invisible container (5, 10, or 15 kg) from the floor, or lifted and manipulated it from the right to the left. The latter involved twisting of the lower back and would be very painful for CLBP patients. All participants recognized the displayed actions, but CLBP patients were impaired in judging the difference in handled weights, especially for the trunk rotation. The second experiment involved discrimination between forward and backward walking. Here the patients were just as good as the controls, showing that the main result of the first experiment was indeed specific to the sensory aspects of the task, and not to general impairments or attentional deficits. The results thus indicate that the judgment of sensorimotor aspects of a visually displayed movement is specifically affected by chronic low back pain.
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Atención/fisiología , Juicio/fisiología , Dolor de la Región Lumbar/fisiopatología , Dolor de la Región Lumbar/psicología , Percepción de Movimiento/fisiología , Nociceptores/fisiología , Percepción Visual/fisiología , Levantamiento de Peso/fisiología , Adulto , Anciano , Mapeo Encefálico , Síndromes de Dolor Regional Complejo/enfermería , Síndromes de Dolor Regional Complejo/fisiopatología , Síndromes de Dolor Regional Complejo/psicología , Discriminación en Psicología/fisiología , Femenino , Humanos , Masculino , Persona de Mediana Edad , Actividad Motora/fisiología , Orientación/fisiología , Dimensión del Dolor , Rango del Movimiento Articular/fisiología , Tiempo de Reacción/fisiología , Valores de Referencia , Filtrado Sensorial/fisiología , Caminata/fisiologíaRESUMEN
Three experiments examined the effects of symmetry and complexity, as facial structures, on the aesthetic judgments of faces, and how these effects are modulated by moderate or massive familiarization. Results showed that symmetrical faces were judged as more attractive than nonsymmetrical faces, and simple faces were judged as more attractive than complex faces-with complexity defined as the number of facial elements. Complexity in faces seemed to have overridden the usually positive effects of facial symmetry. Moreover, while moderate familiarization did not modulate the effects, massive familiarization to a specific face type resulted in structural generalization effects: participants provided higher aesthetic judgments to faces that were new, but similarly structured to those which they were familiarized. This latter result contrasts previous studies that have found structural contrast effects following familiarization to meaningless, abstract stimuli. Taken together, these results reflect the greater biological and social significance of faces as compared to other objects in the world. They also show that people are drawn to those with familiar characteristics.
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Estética/psicología , Cara/anatomía & histología , Generalización Psicológica , Reconocimiento en Psicología , Adulto , Animales , Femenino , Humanos , Juicio , Masculino , Adulto JovenRESUMEN
We investigated whether the mere presentation of single-digit Arabic numbers activates their magnitude representations using a visually-presented symbolic same-different task for 20 adults and 15 children. Participants saw two single-digit Arabic numbers on a screen and judged whether the numbers were the same or different. We examined whether reaction time in this task was primarily driven by (objective or subjective) perceptual similarity, or by the numerical difference between the two digits. We reasoned that, if Arabic numbers automatically activate magnitude representations, a numerical function would best predict reaction time; but if Arabic numbers do not automatically activate magnitude representations, a perceptual function would best predict reaction time. Linear regressions revealed that a perceptual function, specifically, subjective visual similarity, was the best and only significant predictor of reaction time in adults and in children. These data strongly suggest that, in this task, single-digit Arabic numbers do not necessarily automatically activate magnitude representations in adults or in children. As the first study to date to explicitly study the developmental importance of perceptual factors in the symbolic same-different task, we found no significant differences between adults and children in their reliance on perceptual information in this task. Based on our findings, we propose that visual properties may play a key role in symbolic number judgements.
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Juicio , Conceptos Matemáticos , Reconocimiento Visual de Modelos/fisiología , Tiempo de Reacción , Simbolismo , Adolescente , Adulto , Femenino , Humanos , Masculino , Adulto JovenRESUMEN
In a recent paper, we provided independent evidence on the accuracy of 'haptically' measured geographical slant perception (Taylor-Covill & Eves, 2013). Durgin (2013) argues that the devices used in our work, namely the palm-board, and palm-controlled inclinometer (PCI), are not measures of perception. In response, we outline four failures of replication in the laboratory work of Durgin and colleagues on which they base their model of slant perception. We also highlight fundamental differences between the perceptual tasks Durgin and colleagues ask of participants relative to those of Proffitt and colleagues' traditional measures. These subtle differences might help explain how the two groups have arrived at discrepant conclusions.
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Mano/fisiología , Percepción Espacial , Percepción del Tacto , Femenino , Humanos , MasculinoRESUMEN
It is surprising how easily we are able to recognize people whom we have not seen in many years, somehow compensating for the aging-related facial changes that occurred. We measured the limits of the ability to recognize faces across the lifespan by young versus old men and women. Images of five males and five females at young and middle ages were morphed in 10% increments to create aged face images across the lifespan. Fifty-eight participants (28 females) judged whether pairs of photographs were of the same or different identity. Women outperformed men for female faces, exhibiting a sex difference and own-sex bias. Additionally, older participants showed an own-age bias and outperformed their younger counterparts with older stimuli. It appears that the recognition of faces is affected by the own-age and own-sex biases, potentially allowing us to remember some people better than others, thus mediating our interaction with the world.
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Cara , Reconocimiento Visual de Modelos , Prejuicio , Adolescente , Adulto , Factores de Edad , Envejecimiento , Femenino , Humanos , Masculino , Factores Sexuales , Adulto JovenRESUMEN
The finding that repeated exposure to a stimulus enhances attitudes directed towards it is a well-established phenomenon. Despite this, the effects of exposure to products are difficult to determine given that they could have previously been exposed to participants any number of times. Furthermore, factors other than simple repeated exposure can influence affective evaluations for stimuli that are meaningful. In our first study, we examined the influence of existing familiarity with common objects and showed that the attractiveness of shapes representing common objects increases with their rated commonness. In our second study, we eliminated the effects of prior exposure by creating fictitious yet plausible products; thus, exposure frequency was under complete experimental control. We also manipulated the attention to be drawn to the products' designs by placing them in contexts where their visual appearance was stressed to be important versus contexts in which it was indicated that little attention had been paid to their design. Following mere exposure, attractiveness ratings increased linearly with exposure frequency, with the slope of the function being steeper for stimuli presented in an inconspicuous context-indicating that individuals engage in more deliberate processing of the stimuli when attention is drawn to their visual appearance.
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Percepción de Forma , Generalización de la Respuesta , Reconocimiento en Psicología , Adulto , Atención , Femenino , Humanos , Masculino , Persona de Mediana Edad , Adulto JovenRESUMEN
This study investigated how frequency demand and motion feedback influenced composite ocular movements and eye-hand synergy during manual tracking. Fourteen volunteers conducted slow and fast force-tracking in which targets were displayed in either line-mode or wave-mode to guide manual tracking with target movement of direct position or velocity nature. The results showed that eye-hand synergy was a selective response of spatiotemporal coupling conditional on target rate and feedback mode. Slow and line-mode tracking exhibited stronger eye-hand coupling than fast and wave-mode tracking. Both eye movement and manual action led the target signal during fast-tracking, while the latency of ocular navigation during slow-tracking depended on the feedback mode. Slow-tracking resulted in more saccadic responses and larger pursuit gains than fast-tracking. Line-mode tracking led to larger pursuit gains but fewer and shorter gaze fixations than wave-mode tracking. During slow-tracking, incidences of saccade and gaze fixation fluctuated across a target cycle, peaking at velocity maximum and the maximal curvature of target displacement, respectively. For line-mode tracking, the incidence of smooth pursuit was phase-dependent, peaking at velocity maximum as well. Manual behavior of slow or line-mode tracking was better predicted by composite eye movements than that of fast or wave-mode tracking. In conclusion, manual tracking relied on versatile visual strategies to perceive target movements of different kinematic properties, which suggested a flexible coordinative control for the ocular and manual sensorimotor systems.
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Percepción de Movimiento , Reconocimiento Visual de Modelos , Desempeño Psicomotor , Movimientos Sacádicos , Adulto , Atención , Fenómenos Biomecánicos , Retroalimentación Sensorial , Femenino , Humanos , Masculino , Dinamómetro de Fuerza Muscular , Tiempo de Reacción , Procesamiento de Señales Asistido por ComputadorRESUMEN
The aim of this study was to investigate the role of online vision of a target object and the participant's moving hand in the early phase of reach-to-grasp movements. We designed an experiment that separately manipulated the visibility of a moving hand and the target object by using two liquid crystal shutter plates placed in the same horizontal plane (25 cm above the experimental table). When target view was available immediately after movement onset, the effect of hand view in the early phase of movement was very limited. The effect of hand view appeared when target view in the early phase of movement was not available. This was even the case for the condition where the temporal range of non-availability of target view after movement initiation was 150 ms. Therefore, online vision (of target and hand) for controlling grasping was utilized in a flexible fashion that depended on the visual environment.
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Retroalimentación Sensorial , Fuerza de la Mano , Percepción de Movimiento , Orientación , Propiocepción , Desempeño Psicomotor , Tiempo de Reacción , Adolescente , Femenino , Humanos , Masculino , Psicofísica , Privación Sensorial , Percepción del Tamaño , Adulto JovenRESUMEN
Evidence suggests that binding, or encoding a feature with respect to other features in time and space, can convey cognitive advantages. However, evidence across many kinds of stimuli and paradigms presents a mixed picture, alternatively showing cognitive costs or cognitive advantages associated with maintaining bound representations. We examined memory for colored letters drawn from similar and distinct color sets under circumstances that encouraged or discouraged the maintenance of color-letter binding. Our results confirmed previous change recognition research showing feature recognition improvement under explicit instructions to maintain binding. Color memory improved during binding, showing a reduced detrimental effect of feature similarity on retrieval, particularly when the letter served as the retrieval cue for a letter-color object. We found that feature recognition improved when two conditions were met: 1) relationships between features were to-be-remembered, and 2) the feature conjunction was relevant at test. Our results further suggest that this feature advantage arises because the encoded relationship between the features facilitates retrieval, not because features and objects are represented simultaneously in separate buffers.
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Percepción de Color/fisiología , Memoria a Corto Plazo/fisiología , Reconocimiento Visual de Modelos/fisiología , Adolescente , Adulto , Señales (Psicología) , Femenino , Humanos , Masculino , Adulto JovenRESUMEN
This study investigates enhanced visuomotor processing of phobic compared to fear-relevant and neutral stimuli. We used a response priming design to measure rapid, automatic motor activation by natural images (spiders, snakes, mushrooms, and flowers) in spider-fearful, snake-fearful, and control participants. We found strong priming effects in all tasks and conditions; however, results showed marked differences between groups. Most importantly, in the group of spider-fearful individuals, spider pictures had a strong and specific influence on even the fastest motor responses: Phobic primes entailed the largest priming effects, and phobic targets accelerated responses, both effects indicating speeded response activation by phobic images. In snake-fearful participants, this processing enhancement for phobic material was less pronounced and extended to both snake and spider images. We conclude that spider phobia leads to enhanced processing capacity for phobic images. We argue that this is enabled by long-term perceptual learning processes.