While the facilitation-competition paradigm under the stress-gradient hypothesis has received recent attention, its rigorous testing is yet to be explored. Most of the studies have considered a switch in the net interactions from competition to facilitation with increasing environmental stress as primary evidence supporting the hypothesis, though few studies examined changes in interaction along a full range of a stress gradient. Here, we have conceptualized possible variations in the patterns of change in interaction strength along such gradient. Based on this, we empirically evaluated the temporal shift in the interaction between two marine sessile animals, goose barnacles (Capitulum mitella) and mussels (Septifer virgatus), under multiple stress factors. The net effect of goose barnacles on mussel survivorship was positively related to the total stress gradient encompassing two stress factors, physical disturbance and thermal stress, while no negative value occurred even under mild conditions. When the two stress factors were treated separately, however, the net effect demonstrated apparently different patterns: monotonic increase with physical disturbance versus a quasi-asymptotic pattern (no change over a wide range) with thermal stress. These variable situations have not previously been recognized in this discipline, and the present study emphasizes the importance of an integrative and mechanistic approach to testing and deciphering the facilitation-competition paradigm.

Animals monitor the outcome of their choice and adjust subsequent choice behavior using the outcome information. Together with the anterior cingulate cortex (ACC), the lateral habenula (LHb) has recently attracted attention for its crucial role in monitoring negative outcome. To investigate their contributions to subsequent behavioral adjustment, we recorded single-unit activity from the LHb and ACC in monkeys performing a reversal learning task. The monkey was required to shift a previous choice to the alternative if the choice had been repeatedly unrewarded in past trials. We found that ACC neurons stored outcome information from several past trials, whereas LHb neurons detected the ongoing negative outcome with shorter latencies. ACC neurons, but not LHb neurons, signaled a behavioral shift in the next trial. Our findings suggest that, although both the LHb and the ACC represent signals associated with negative outcome, these structures contribute to subsequent behavioral adjustment in different ways.

No abstract

No abstract

No abstract

Distribution and seasonal fluctuation of the bacteria which inhibit the growth of a red tide marine dinoflagellate Gymnodinium mikimotoi, were surveyed in Tanabe Bay (Wakayama Pref., Japan), us ing the newly developed MPN method with an axenic culture of G. mikimotoi. G. mikimotoi's growth inhibiting bacteria (Gm-GIB) were detected at 103-104 cells/ ml before occurrences of huge red tides by G. mikimotoi at the beginning of August in 1990 and from the end of August to the beginning of Sep tember in 1991. The number of Gm-GIB fell by about two orders of magnitude at the blooming periods of G. mikimotoi, and then increased again after the blooms declined. These results suggest that the fluc tuation of Gm-GIB counts in seawater is significantly related to the development and decline process of G. mikimotoi red tide. Forty strains of Gm-GIB isolated in this study all acted as killers against this dinoflagellate rather than as suppressers on the algal growth under laboratory conditions. The precise causes of the fluctuation of Gm-GIB in seawater environments remain unknown.

We measured the eye movements of participants who watched a 6-minute movie in stereoscopic and non-stereoscopic form. We analyzed four shots of the movie. The results indicate that in a 2D movie viewers tended to look at the actors, as most of the eye movements were clustered there. The significance of the actors started at the beginning of a shot, as the eyes of the viewer focused almost immediately to them. In S3D movie the eye movement patterns were more widely distributed to other targets. For example, complex stereoscopic structures and objects nearer than the actor captured the interest and eye movements of the participants. Also, the tendency to first look at the actors was diminished in the S3D shots. The results suggests that in a S3D movie there are more eye movements which are directed to wider array of objects than in a 2D movie. INTRODUCTIONThe purpose of a moviemaker is to influence the viewers to pay attention to salient events of the script, so that the viewers understand the details, consequences and emotional significance of events 1 . This can be accomplished by utilizing for example shot distance, focus, angle, movement, point of view, scene composition and principles of cutting 1,2 . In a stereoscopic film the effect of these techniques might be different, as the processes of stereoscopic vision affect the way viewers pay attention and understand the scenes. Moviemakers and stereographers know how to utilize the possibilities of stereoscopy, as recent excellent stereoscopic films have shown, but there is less empirical data related to these effects. According to our recent studies the viewers most often mention experiences of reality-likeness, presence, enhanced emotions and richness of structural details when watching a stereoscopic movie 3,4 . Asking the viewers to describe their experiences is the best way to form an understanding of the underlying psychological processes 5-8 , so these results tell us a lot about the experiential added value of stereoscopy. However, there are also processes that are not consciously accessible. These processes might be reflexive, automatic or too quick to enter the consciousness of the viewer. For example, eye movements and the related changes in the focus of attention are only partially guided by conscious intentions of the viewers. As the locations where the eyes stop to collect information determine what parts of the visual environment we notice, measuring the eye movements with stereoscopic film shows, which part of each shot is regarded as informative and important.Eye movements can be divided to two main phases. Firstly, there are fixations when the eye is pointing to a single location of the scene. Secondly, there are saccades when the eyes quickly move the point of regard to another position. Information is acquired during fixations, as during the saccades the information from the eye is mostly suppressed. Experiments suggest that viewers look at the most informative areas of the scene. The definition of informative depends on the task and the cont...

Abstract— This paper describes a method for reducing the discrepancy between accommodation and convergence when viewing stereoscopic 3‐D images. The method uses a newly developed stereoscopic 3‐D display system with a telecentric optical system and a mobile LCD. The examination of a mono‐focal lens showed that a correction lens having the appropriate refractive power and conditions for presenting stereoscopic 3‐D images clearly reduces the discrepancy between accommodation and convergence. The authors also developed a stereoscopic 3‐D display that uses dynamic optical correction to reduce the discrepancy between accommodation and convergence. The display equalizes the theoretical points of accommodation and convergence. The purpose of the development was to expand the regeneration range of a stereoscopic 3‐D image having the appropriate accommodation. An evaluation of the developed display showed that it resolves the discrepancy between convergence and accommodation.