The evolution of virulence was studied in a virus subjected to alternating episodes of vertical and horizontal transmission. Bacteriophage f1 was used as the parasite because it establishes a debilitating but non-fatal infection that can be transmitted vertically (from a host to its progeny) as well as horizontally (infection of new hosts). Horizontal transmission was required of all phage at s...

We measured the eye movements of three sisters with Niemann-Pick type C disease who had a selective defect of vertical saccades, which were slow and hypometric. Horizontal saccades, and horizontal and vertical pursuit and vestibular eye movements were similar to control subjects. The initial movement of oblique saccades was mainly horizontal and most of the vertical component occurred after the...

We compared horizontal and vertical smooth pursuit eye movements in five healthy human subjects. When maintenance of pursuit was tested using predictable waveforms (sinusoidal or triangular target motion), the gain of horizontal pursuit was greater, in all subjects, than that of vertical pursuit; this was also the case for the horizontal and vertical components of diagonal and circular tracking...

Vertical phoria (vertical vergence in the absence of binocular feedback) can be trained to vary with non-visual cues such as vertical conjugate eye position, horizontal conjugate eye position and horizontal vergence. These prior studies demonstrated a low-level association or coupling between vertical vergence and several oculomotor cues. As a test of the potential independence of multiple eye-...

multinational corporations (mncs) are major actors in contemporary world. their negative and positive impacts on human life make clear the need for expanding their responsibilities. the aim of this article is to show how responsibilities of mncs evolve during recent 50-60 years. through two sections, the article examines vertical and horizontal expansion of mncs’ responsibilities and then recen...

The world is three-dimensional; hence, even surface-bound animals need to learn vertical spatial information. Separate encoding of vertical and horizontal spatial information seems to be the common strategy regardless of the locomotory style of animals. However, a difference seems to exist in the way freely moving species, such as fish, learn and integrate spatial information as opposed to surf...

PURPOSE To evaluate and compare the observers' ability to measure simulations of cup/disc ratios (CDR) as concentric and non-concentric circles. METHODS In a prospective, random, and masked setting, 43 images representing the CDR spectrum from 0.2 to 0.9 for vertical and horizontal CDR measurements were developed and presented on a computer screen to 171 participants. RESULTS There were sat...

statement of problem: among periodontal defects, the furcation involvement represents one of the most chalenging scenarios due to the difficulty of achieving a predictable improvement regardless of the type of periodontal therapy. moreover, the presence of furcation involvement has been demonstrated to considerably affect tooth prognosis. thus, treatment of furcation defects is a challenge in c...

Although not currently a widely accepted notion, evidence suggests an anisotropy between horizontal and vertical orientations in visual processing. While there is evidence of an early neurological bias due to a greater number of cortical neurons tuned to the horizontal orientation, recent behavioral evidence suggests a “horizontal effect”, where performance for broadband horizontal stimuli is w...