Attention and distraction in the modular visual system of a jumping spider

Animals must selectively attend to relevant stimuli and avoid being distracted by unimportant stimuli. Jumping spiders (Salticidae) do this by coordinating eyes with different capabilities. Objects are examined by a pair of high-acuity principal eyes, whose narrow field of view is compensated for by retinal movements. The principal eyes overlap in field of view with motion-sensitive anterior-lateral eyes, which direct their gaze to new stimuli. Using a salticid-specific eyetracker, we monitored the gaze direction of the principal eyes as they examined a primary stimulus. We then presented a distractor stimulus visible only to the ALEs and observed whether the principal eyes reflexively shifted their gaze to it or whether this response was flexible. Whether spiders redirected their gaze to the distractor depended on properties of both the primary and distractor stimuli. This flexibility suggests that higher-order processing occurs in the management of the attention of the principal eyes.

Anisotropic Psychophysical Trends in the Discrimination of Tactile Direction in a Precision Grip

Tactile cues arising from interactions with objects have a sense of directionality which affects grasp. Low latency responses to varied grip perturbations indicate that grasp safety margins are exaggerated in certain directions and conditions. In a grip with the ulnar-radial axis vertical, evidence suggests that distal and downward directions are more sensitive to task parameters and have larger safety margins. This suggests that, for the purpose of applying forces with the fingers, reference frames with respect to the hand and gravity are both in operation. In this experiment, we examined human sensitivities to the direction of tactile movement in the context of precision grip in orientations either orthogonal to or parallel to gravity. Subjects performed a two-alternative-forced-choice task involving a textured cube which moved orthogonal to their grip axis. Subjects’ arms were placed in a brace that allowed for finger movement but minimized arm movement. Movement of thumb and index joints were monitored via PhaseSpace motion capture. The subject was presented with a textured cube and instructed to lightly grasp the cube, as if it were slipping. In each trial the object was first translated 1 cm in 0° (proximal), 90° (radial), 180° (distal), or 270° (ulnar) and returned to its origin. This primary stimulus was immediately followed by a 10 mm secondary stimulus at a random 5° interval between −30° and 30° of the primary stimulus. Response from the subject after each pair of stimuli indicated whether the test direction felt the same as or different from the primary stimulus. Traditional bias and sensitivity analyses did not provide conclusive results but suggested that performance is best in the ulnar-radial axis regardless of gravity. Modeling of the response curve generated a detection threshold for each primary stimulus. Lower thresholds, indicating improved detection, persisted in the ulnar-radial axis. Anisotropic thresholds of increased detection appear to coincide with digit displacement and appear to be independent of the grasp orientation.

Anti-Westernism as a criterion for pretending to be revolutionary in Iran and its application as an effective tool in removing political rivals

What has been less visible to observers over more than Iran’s thirty years political events or, in other words, what was actually formed the motivation power of government system after the 1979 revolution, was located under the shadow of a vast tree of religion, is a kind of xenophobia and, in its particular form, is anti-Western. It can be argued that the contents, capacity and role of this religion without any “anti-Western” anticipation were useless and deficient to the Iranian Shiite rulers. The basis of the discussion in this article is the context in which a kind of anti-modernization grew from within and became the dominant discourse of society headed by traditional clergy. What is being discussed in this article is to fingers on the main stimulus and the central tool of production of legitimacy, and its role and application in conjunction with the political ideology of rule in Iran. In this regard, the present article seeks to explain how this primary stimulus has evolved and how it is used as a political tool but in the form of ideology.

John D. Cooper and His Demonstration of a Curtiss Flying Boat in Istanbul, 1914: The First American Aircraft Sold to Turkey

This article describes the career of John D. Cooper, an early American aviator and a leading test pilot for Glenn Curtiss. In the latter role he demonstrated a Curtiss flying boat in Istanbul in 1914 before a massive crowd. This aircraft was subsequently sold to Turkey and provided the primary stimulus to Ottoman naval aviation. It was also the first American aircraft sold in the Middle East.

The Influence of Selected Type of Daylight Device on Horizontal and Vertical Internal Illuminance

Daylighting is one of the key parameters of internal environment generation in buildings. This parameter determines creation of suitable conditions for visual activities in internal spaces and contributes to human well-being and comfort. Daylight is also the primary stimulus for synchronizing the human circadian photobiological system. Traditional parameters and criterions based explicitly on photopic vision have been critically re-evaluated and basic principles of circadian photometry have been developed in theoretical level. Nevertheless daylighting has often been neglected or left out from the main design proposals, which are usually just focused on covering basic needs for vision tasks represented barely by the illumination limits on working plane. Because the amount of light entering the eye is the most important for circadian entrainment, the illuminance recorded on a vertical plane, at eye level, is more significant for human biological system. This paper deals with the comparison of internal horizontal and vertical illuminance recorded in 3 models of room, inserted in simulation program Radiance and illuminated by three types of lighting devices, i.e. window, light-pipes and permanent supplementary artificial lighting represented by the combination of window and light-pipes. Achieved data also express the influence of a workplace position on the amount of illuminance entering the eye according to the direction of the incoming daylight from windows in side-lit room.

Parallel and divergent adaptations of rat soleus and plantaris to chronic exercise and hypergravity

It has been demonstrated that endurance exercise and chronic acceleration, i.e., hypergravity, produce comparable adaptations in a variety of physiological systems, including decreased adiposity, increased energy metabolism, and altered intermediary metabolism. Similar adaptations have not been demonstrated for skeletal muscle per se. To further differentiate between these general responses with respect to gravity and exercise, this study tested the hypothesis that chronic exercise (voluntary wheel running) and chronic acceleration (2 G via centrifugation) will induce similar changes in muscle myosin heavy chain (MHC) isoform expression in rat plantaris, a fast extensor, and in rat soleus, a slow “antigravity” extensor. The experimental design involved four groups of mature male rats ( n = 8/group): 1 G and 2 G with running wheels, and 1 G and 2 G controls without running wheels. The primary observations from the study were as follows: 1) 8 wk of 2 G are an adequate stimulus for MHC compositional changes in rat plantaris and soleus muscle; 2) both exercise and +G caused an increase in the slow MHC1 isoform in soleus muscle, suggesting that loading is a primary stimulus for this shift; and 3) 2 G and exercise appeared to have differential effects on the plantaris muscle MHC isoforms, with 2 G causing an increase in MHC2b, and exercise causing a decrease in MHC2b with a concomitant increase in MHC1, suggesting that factors other than enhanced loading, possibly locomotor activity levels, are the primary stimulus for this shift.

Predominant activation of endothelin-dependent cardiac hypertrophy by norepinephrine in rat left ventricle

Locally released endothelin (ET)-1 has been recently identified as an important mediator of cardiac hypertrophy. It is still unclear, however, which primary stimulus specifically activates ET-dependent signaling pathways. We therefore examined in adult rats ( n = 51) the effects of a selective ETA receptor antagonist in experimental models of cardiac hypertrophy, in which myocardial growth is predominantly initiated by a single primary stimulus. Rats were exposed to mechanical overload (ascending aortic stenosis), increased levels of circulating ANG II (ANG II infusion combined with hydralazine), or adrenergic stimulation (infusion of norepinephrine in a subpressor dose) for 7 days. All experimental treatments significantly increased left ventricular weight/body weight ratios compared with untreated rats, whereas systolic left ventricular peak pressure was increased only after ascending aortic stenosis. ETA receptor blockade exclusively reduced norepinephrine-induced cardiac hypertrophy and atrial natriuretic peptide gene expression. Blood pressure levels and heart rates remained unaffected during ETA receptor blockade in all experimental groups. These data indicate that in rat left ventricle, the ET-dependent signaling pathway leading to early development of cardiac hypertrophy and fetal gene expression is primarily activated by norepinephrine.

Role of prostaglandins in intrauterine migration of the equine conceptus

Between at least day 9 and day 16 after ovulation the spherical equine conceptus migrates continuously throughout the uterine lumen, propelled by peristaltic myometrial contractions. This unusually long period of intrauterine movement ensures that the conceptus delivers its anti-luteolytic signal to the entire endometrium to achieve luteostasis. The present experiment tested the hypothesis that prostaglandins stimulate the myometrial contractions that result in the migration of the conceptus. Serial ultrasonographic examinations of the uteri of eight mares performed during 2 h periods between day 10 and day 18 of gestation recorded the pattern of conceptus migration before and after treatment with the cyclo-oxygenase inhibitor flunixin meglumine. Conceptus mobility was high between day 10 and day 14 after ovulation (4.3 +/- 0.8, 4.7 +/- 0.8 and 4.3 +/- 0.9 changes of location per h on day 10, day 12 and day 14, respectively), but was reduced immediately and markedly by an i.v. injection of flunixin meglumine (3.8 +/- 1.5, 1.8 +/- 0.8 and 0.7 +/- 0.2 location changes per h), thereby implicating prostaglandins as the primary stimulus for the myometrial contractions that drive migration of the conceptus.