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The spatial separation of the eyes causes a difference in the images in the two eyes formed by a solid object. These differences, or binocular disparities, form the basis for stereoscopic vision. This chapter discusses the extent to which each of these differences is used as a basis for stereopsis. Topics covered include feature tokens for stereopsis, monocular occlusion, occlusion as a depth token, stereopsis from illusions, chromostereopsis, and irradiation stereopsis.

This chapter discusses the strengths and weaknesses of techniques of 3D laser imaging based on time of flight and triangulation. Laser scanning by triangulation is a fully developed technology. Through this method, it is now possible to create faithful 3D datasets from a reasonable range of surface materials. However, laser scanning has some certain drawbacks, restricting their universal applicability. For surfaces with concavities or with intricate details, occlusion may occur due to the necessary separation of the viewpoint between the viewing camera and the laser projector. In addition, the data may be corrupted by false and poor returns caused by variable material reflectance. In the time of flight system, the distance is measured by measuring the time for a focused laser beam to impact on and return from the surface of interest. In this method, the distance is computed and a 3D image can be created if the laser beam is scanned across the target. Although, the time of flight method is a more attractive alternative as it eliminates occlusion, it has disadvantages as well. The time resolution necessary to measure the range to sub-millimetre accuracy is difficult to achieve and the measured time is also affected by the magnitude of the returned signal. In addition to reviewing the pros and cons of this current technology, the chapter also discusses the development of a new approach to time-of-flight laser imaging based on time-correlated single photon counting. This new method has various advantages compared to the old methods. It has the ability to make 3D measurements on distance, poorly reflecting or transparent surfaces.

This chapter contemplates the question of how a doctrine of mystery can provide measure for ones' life. Firstly, it explains how the issue it addresses was reached. Secondly, it argues that one may discern how various conceptions, beliefs, and comportments are consonant to the experience of mystery. Thirdly, it discusses in detail the disconsonant concepts based on confrontation, degradation, and occlusion. The chapter concludes by discussing the finer aspects of humility.

Question 1.1

How would you classify this incisor relationship?

What are the other occlusal features you can see?

What are Andrew’s six keys to normal static occlusion?

What is the difference between an Angle’s and an Andrew’s class I molar relationship?...

While several different neural processes contribute to the perception of biological motion, the responsiveness of a key area, the human superior temporal sulcus (STS), to biological motion appears to be driven largely by the need to integrate motion information with configural body form information. This need reflects the fact that the human body produces complex patterns of articulated motions at multiple spatial locations that are linked by the underlying human form. Such a global integration of motion and form information would provide several advantages to observers of human movement across a variety of otherwise challenging conditions including brief durations, occlusion, and observer movement.

One of the primary features of Christianity is that it accommodates the whole of the suffering of humankind, a suffering that is both moral and physical. Nonetheless the burden of suffering and salvation through suffering have often been confused together. Christ does not tell us either what or why he suffers. But he guides us in how he suffers. Closed in on oneself or open to the other: These are the two ways of living suffering, by which suffering becomes a manner of living rather just a condemnation of life.

This chapter focuses on malignant bowel obstruction (MBO), a common complication in women diagnosed with ovarian cancer, colorectal cancer, and other gynaecological malignancies. MBO generally afflicts 25–42 per cent of patients with advanced ovarian cancer, but rarely occurs in patients with endometrial cancer. MBO develops by the existence of mechanical obstruction from an extrinsic occlusion of the bowel lumen, intraluminal occlusion of the lumen, luminal obstruction due to tumour growth in the bowel wall, and adynamic ileus. Bowel obstruction can also be caused by other non-malignant factors such as adhesion, post-irridation bowel damage, hernias, and inflammatory bowel disease. Management of MBO includes pain management, pharmacological management, and non-pharmacological management. In patients with MBO, pharmacological treatment is generally successful. Only patients who are strictly considered as appropriate candidates for surgery and parenteral nutrition are given such treatments.

Arteries relax in response to some vasodilators only if the endothelium is present. The obligatory role for vasodilatation of a diffusible factor from endothelium termed ‘EDRF’ for endothelial-dependent relaxing factor, now identified as nitric oxide or a related nitroso-thiol has been demonstrated for many agents, including acetylcholine, bradykinin, substance P, ATP, other adenine nucleotides — and especially important for this chapter — the vasodilator action of 5-HT. Other vasodilator agents, however, such as nitrates, papaverine, isoproterenol, and prostaglandins, do not require endothelium. This chapter focuses on pharmacological considerations in atherosclerosis and in the collateral arteries that grow in response to the vascular occlusion that so often occurs with atherosclerosis.

This chapter, as its title suggests, is concerned primarily with practical issues surrounding amblyopia therapy. Imprecise or inappropriate measurement techniques have limited understandings of occlusion therapy. To examine these issues the chapter draws upon observations made in the literature and on some techniques recently developed in the laboratory. Finally, experimental data that indicate how proposals work in practice are presented. The discussions are necessarily restricted in scope and do not address the many neuroscientific contributions that have increased the understandings of this curious condition. Throughout this chapter the attention is focused on the amblyopic child as opposed to the infant and the chapter defines the former as being of an age at which a visual task involving ‘linear’ optotypes can be performed, either by the elicitation of a verbal response or by the child indicating the target seen at distance on a hand-held key card. Also, it makes no specific reference to the taxonomy of amblyopia although it acknowledge this to be an obvious factor likely to influence treatment outcome. At the beginning of this chapter, attention is drawn to the lack of empirical (as opposed to clinical, anecdotal) support for the use of occlusion therapy. It is suggested that this arose because of inadequate or inappropriate measurement of compliance and visual outcome.

It has been reported that infants represent the continued existence of an object through occlusion and they can track even multiple objects. Many studies have found that infants track the discrete numerosity of small sets of objects in multiple modalities, but the interpretation of these findings remains controversial. In this chapter, the authors evaluate the available evidence for four theories that have been proposed to explain how infants track discrete quantity namely: object indexing, sets, mental magnitudes/accumulator, and integers. Of the four theories, only the accumulator and the generative integer views posit an irreducibly numerical basis to infants' number representations. The object indexing and set accounts provide a mechanism by which infants might be able to track small numbers of discrete objects and compare them on the basis of their numerical identity without actually being able to count.

This chapter identifies the occlusions that are created by current organisations of knowledge for Renaissance texts. It argues that the post-Cartesian segregation of cognition from corporeality prevents one from stopping the connection between aesthetic practice and physiological concept in the Renaissance. The chapter then tries to determine whether passionate and argumentative poetic expressions provide happiness that is both intellectual and primeval.

This chapter discusses the results of a series of experiments aimed at investigating visual-information processing in baboons. Two lines of research on baboons are presented in this chapter. The first one explores the processes of perceptual grouping. In comparison to humans when similarly tested, baboons barely group spatially separated elements into a single percept. The second one addresses the issue of depth perception. Baboons perceive depth when presented with pictorial depth cues, but the study also highlights human–baboon differences in the processing of occlusion cues as indicators of depth. A local precedence effect was observed in baboons, in contrast to humans, who showed a global precedence effect. Experiments further revealed that local precedence in baboons is a direct consequence of their difficulty in overcoming the separation between the local elements, a necessary process for perceiving the whole. Moreover, baboons perceive the corridor illusion, suggesting that they gain depth information from the pictorial cues available in the image background.

Ophthalmology principally aims to prevent visual loss, restore visual function, and relieve ocular discomfort. The majority of the pathology can be directly visualized and thus requires proficient ocular examination techniques and visual recognition skills. Another distinguishing aspect of ophthalmology is the overlap between medical and surgical conditions. Common systemic diseases such as diabetes and hypertension have ocular features, and diseases involving every organ of the body can have ocular manifestations. A thorough medical knowledge is paramount, as is the ability to collaborate with other medical teams. Intraocular surgery for conditions such as cataract is technically challenging, as ocular tissues are so delicate. It therefore requires high levels of fine hand–eye coordination. As an ophthalmologist, you will be faced both with acute eye conditions, some of which are sight-threatening and require prompt diagnosis and management, and with chronic conditions, which require monitoring and treatment for many years. You will be exposed to patients of all ages, from premature babies to the elderly, so good communication with a wide range of patient groups and their families is essential. Patients often say that what they fear most is losing their sight. Therefore, empathy and support for patients with debilitating visual impairment are imperative. The questions in this chapter will test your knowledge of acute emergency ophthalmic presentations and the understanding and interpretation of ophthalmic examination, as well as ocular conditions that have systemic associations. In addition, questions relating to ophthalmic risk factors, communication, and probity are included. Eye problems can be daunting to many medical students and doctors. Through practice in examining patients and recognizing key conditions, confidence can be gained in how best to manage these patients and, importantly, when to refer them to other specialties. Ophthalmology incorporates a unique and appealing mix of medical and surgical conditions. It is a rapidly advancing specialty with recent significant advances in diagnostic and therapeutic options. It also provides an opportunity for a good work–life balance.

Pathologic processes involving the retina or choroid can present with a wide variety of visual field defects. Usually visual field defects of retinal diseases directly correlate with the fundus findings. Visual field changes are often the result of damage to the retina or scarring but, in conjunction with other clinical findings, they may help narrow the differential diagnosis. Most of the macular lesions result in visual field defects that do not respect the vertical or horizontal midline. Occasionally inflammatory disorders result in visual field defects that do not directly correlate with the retinal findings. For example, patients with multiple evanescent white dot syndrome (MEWDS) may have an enlarged blind spot. Macular disorders can cause central or paracentral scotomas depending on the location of the lesion. Causes of macular pathology include drusen, atrophy from dry age-related macular degeneration (AMD), retinal hemorrhage, choroidal neovascular membrane, macular edema, macular hole, macular scar, pathologic myopia, and macular dystrophies of the retina or choroid. Central serous chorioretinopathy (CSCR) can show a relative defect that is anatomically correlated with the area of subretinal or sub RPE (retinal pigment epithelium) fluid accumulation. Residual pigmentary changes in inactive CSCR can also cause a relative depression in the corresponding visual field. Pathologic myopia can present with a variety of visual field defects depending on the retinal findings, such as posterior staphyloma or choroidal neovascular membrane. AMD may show nonspecific changes in the central or paracentral visual field that correlate with the structural damage to the retina and choroid. Geographic atrophy in dry AMD can cause a dense scotoma correlated with the pattern of the atrophy. Choroidal neovascular membranes can cause a depression in the correlating visual field due to edema or hemorrhage. Disciform scars in endstage AMD can also cause a dense scotoma. Macular holes may cause a small central scotoma. Pattern dystrophies are a family of disorders with a common pathology at the level of the RPE. Butterfly dystrophy, an autosomal dominant disorder, and Sjögren reticular dystrophy, an autosomal recessive disorder, are two examples of pattern dystrophies.

Brentano never investigated whether the ‘peculiar feature’ of inner perception—that it can never become inner observation—that distinguishes our awareness of the mental from other forms of perceptual awareness could serve as the mark of the mental. However, his students Stumpf and Husserl developed marks of the mental that are inspired by this idea. The chapter clarifies Husserl’s Thesis that mental phenomena have no appearances, argues that it is superior to Brentano’s Thesis, and defends it against objections from Reinach and Husserl himself. Husserl himself threw out the baby with the bathwater when he later rejected Husserl’s Thesis. A precisified form of this idea can still unify our intuitions about the mental.

Intrinsic to glaucoma surgery using a tube shunt is the management of early postoperative hypotony. This consideration is unavoidable in all cases when using a tube shunt without an intrinsic valve and must still be considered in tube shunts that contain a valve, as the valve may not function as anticipated. Unfortunately, in the attempt to avoid hypotony and its associated complications, we are faced with elevated intraocular pressure (IOP) and its associated difficulties. However, the attempt to control IOP is not the only consideration when anticipating intentional tube occlusion. Additional factors such as technical complexity of the procedure, predictability of IOP in the early postoperative period, potential to reverse occlusion either partially or completely, and the impact on the long-term function of the tube shunt must be considered. The desired endpoint when occluding a tube intentionally is the complete prevention of flow to the tube shunt reservoir. The standard ways to occlude the tube are an external encircling ligature or an internal occluding suture, otherwise known as an “obturator” or a “ripcord,” or some combination thereof. With the external suture technique, prior to placing the reservoir, a 7–0 or 8–0 polyglactin 910 (Vicryl™ , Ethicon, Inc., Somerville, New Jersey) suture is tightly tied around the tube approximately 4–6 mm from the reservoir (Figure 35.1). It is anticipated that this suture will dissolve in about one month, opening the tube. However, the timing of opening may be highly variable between individuals, and that variability may be problematic. Alternatively, a 9–0 polypropylene suture can be placed around the tip of an anterior chamber tube with release performed by laser lysis. To prevent the polypropylene suture from floating freely in the anterior chamber after release, a pass should be made through the wall of the tube during placement. Alternatively, with the “ripcord” technique, the end of a 3–0 polypropylene suture without the needle is threaded into the distal opening of the tube at the reservoir for a distance of 4–6 mm.

Every animal that has a respiratory faculty has some mechanism for regulating its perfusion and ventilation. A prerequisite for such regulation is some way of sensing internal and external levels of respiratory-relevant gases. The regulatory entities can be peripheral, central, or both. This chapter looks at the control of breathing in aquatic and terrestrial invertebrates and concludes that the main signal for aquatic species is oxygen, whereas the internal pH/PCO₂ is most important for the control of air breathing, regardless of the phylogenetic group to which the animal may belong.

This chapter discusses sickle cell disease and related conditions, including biochemical, pathological, and clinical abnormalities and factors to be considered in nutritional evaluation (e.g., growth, nutritional status). Dietary management is specifically discussed, including protein and caloric needs, vitamins and minerals, and effects therapies on growth and development).