The Neuroscience of Visual Hallucinations

Each year, some two million people in the United Kingdom experience visual hallucinations. Infrequent, fleeting visual hallucinations, often around sleep, are a usual feature of life. In contrast, consistent, frequent, persistent hallucinations during waking are strongly associated with clinical disorders; in particular delirium, eye disease, psychosis, and dementia. Research interest in these disorders has driven a rapid expansion in investigatory techniques, new evidence, and explanatory models. In parallel, a move to generative models of normal visual function has resolved the theoretical tension between veridical and hallucinatory perceptions. From initial fragmented areas of investigation, the field has become increasingly coherent over the last decade. Controversies and gaps remain, but for the first time the shapes of possible unifying models are becoming clear, along with the techniques for testing these. This book provides a comprehensive survey of the neuroscience of visual hallucinations and the clinical techniques for testing these. It brings together the very latest evidence from cognitive neuropsychology, neuroimaging, neuropathology, and neuropharmacology, placing this within current models of visual perception. Leading researchers from a range of clinical and basic science areas describe visual hallucinations in their historical and scientific context, combining introductory information with up-to-date discoveries. They discuss results from the main investigatory techniques applied in a range of clinical disorders. The final section outlines future research directions investigating the potential for new understandings of veridical and hallucinatory perceptions, and for treatments of problematic hallucinations. Fully comprehensive, this is an essential reference for clinicians in the fields of the psychology and psychiatry of hallucinations, as well as for researchers in departments, research institutes and libraries. It has strong foundations in neuroscience, cognitive science, optometry, psychiatry, psychology, clinical medicine, and philosophy. With its lucid explanation and many illustrations, it is a clear resource for educators and advanced undergraduate and graduate students.

Adaptive, convergent origins of the pygmy phenotype in African rainforest hunter-gatherers

Tropical rainforest hunter-gatherer populations worldwide share the pygmy phenotype, or small human body size. The evolutionary history of this phenotype is largely unknown. Here we studied DNA from the Batwa, a rainforest hunter-gatherer population from east central Africa, to identify regions of the Batwa genome that underlie the pygmy phenotype. We then performed population genomic analyses to study the evolution of these regions, including comparisons with the Baka, a west central African rainforest hunter-gatherer population. We conclude that the pygmy phenotype likely arose due to positive natural selection and that it arose possibly multiple times within Africa. These results support longstanding anthropological hypotheses that small body size confers an important selective advantage for human rainforest hunter-gatherers.

Blackfolds, plane waves and minimal surfaces

Minimal surfaces in Euclidean space provide examples of possible non-compact horizon geometries and topologies in asymptotically flat space-time. On the other hand, the existence of limiting surfaces in the space-time provides a simple mechanism for making these configurations compact. Limiting surfaces appear naturally in a given space-time by making minimal surfaces rotate but they are also inherent to plane wave or de Sitter space-times in which case minimal surfaces can be static and compact. We use the blackfold approach in order to scan for possible black hole horizon geometries and topologies in asymptotically flat, plane wave and de Sitter space-times. In the process we uncover several new configurations, such as black helicoids and catenoids, some of which have an asymptotically flat counterpart. In particular, we find that the ultraspinning regime of singly-spinning Myers-Perry black holes, described in terms of the simplest minimal surface (the plane), can be obtained as a limit of a black helicoid, suggesting that these two families of black holes are connected. We also show that minimal surfaces embedded in spheres rather than Euclidean space can be used to construct static compact horizons in asymptotically de Sitter space-times.

New geometries for black hole horizons

We construct several classes of worldvolume effective actions for black holes by integrating out spatial sections of the worldvolume geometry of asymptotically flat black branes. This provides a generalisation of the blackfold approach for higher-dimensional black holes and yields a map between different effective theories, which we exploit by obtaining new hydrodynamic and elastic transport coefficients via simple integrations. Using Euclidean minimal surfaces in order to decouple the fluid dynamics on different sections of the worldvolume, we obtain local effective theories for ultraspinning Myers-Perry branes and helicoidal black branes, described in terms of a stress-energy tensor, particle currents and non-trivial boost vectors. We then study in detail and present novel compact and non-compact geometries for black hole horizons in higher-dimensional asymptotically flat space-time. These include doubly-spinning black rings, black helicoids and helicoidal p-branes as well as helicoidal black rings and helicoidal black tori in D ≥ 6.

Effect of the Tiger Stripes on the water vapor distribution in Enceladus' exosphere

The jet activity emanating from Enceladus' exosphere south pole region observed by Cassini is a subject of intensive study. The in situ and remote sensing observations performed since 2005 triggered an active modeling campaign. Such modeling is essential for better understanding of the measurements performed by individual instruments as well as to link them for a more complete picture of the volatile and ice grain distribution in Enceladus' exosphere. This paper is focused on the investigation of the effect that diffuse gas sources along the Tiger Stripes have on distribution of the water vapor in Enceladus' exosphere using the updated version of our multiplume model. We have found that accounting for the gas production by Tiger Stripes is critical for interpretation of the Cassini data. According to our calculations, sources along the Tiger Stripes (apart from those originally identified by Spitale and Porco (2007)) must contribute about 23–32% to the total plume source rate, which varies in the range of (6.4–29) ×1027 s−1. The effect of the previously unidentified source suggested in the paper is found to be critical for explaining the Ultraviolet Imaging Spectrograph 2007 and 2010 observations in the whole range of the elapsed times.

Periodontal regeneration - furcation defects: a consensus report from the AAP Regeneration Workshop

BACKGROUND Treatment of furcation defects is a core component of periodontal therapy. The goal of this consensus report is to critically appraise the evidence and to subsequently present interpretive conclusions regarding the effectiveness of regenerative therapy for the treatment of furcation defects and recommendations for future research in this area. METHODS A systematic review was conducted before the consensus meeting. This review aims to evaluate and present the available evidence regarding the effectiveness of different regenerative approaches for the treatment of furcation defects in specific clinical scenarios compared with conventional surgical therapy. During the meeting, the outcomes of the systematic review, as well as other pertinent sources of evidence, were discussed by a committee of nine members. The consensus group members submitted additional material for consideration by the group in advance and at the time of the meeting. The group agreed on a comprehensive summary of the evidence and also formulated recommendations for the treatment of furcation defects via regenerative therapies and the conduction of future studies. RESULTS Histologic proof of periodontal regeneration after the application of a combined regenerative therapy for the treatment of maxillary facial, mesial, distal, and mandibular facial or lingual Class II furcation defects has been demonstrated in several studies. Evidence of histologic periodontal regeneration in mandibular Class III defects is limited to one case report. Favorable outcomes after regenerative therapy for maxillary Class III furcation defects are limited to clinical case reports. In Class I furcation defects, regenerative therapy may be beneficial in certain clinical scenarios, although generally Class I furcation defects may be treated predictably with non-regenerative therapies. There is a paucity of data regarding quantifiable patient-reported outcomes after surgical treatment of furcation defects. CONCLUSIONS Based on the available evidence, it was concluded that regenerative therapy is a viable option to achieve predictable outcomes for the treatment of furcation defects in certain clinical scenarios. Future research should test the efficacy of novel regenerative approaches that have the potential to enhance the effectiveness of therapy in clinical scenarios associated historically with less predictable outcomes. Additionally, future studies should place emphasis on histologic demonstration of periodontal regeneration in humans and also include validated patient-reported outcomes. CLINICAL RECOMMENDATIONS Based on the prevailing evidence, the following clinical recommendations could be offered. 1) Periodontal regeneration has been established as a viable therapeutic option for the treatment of various furcation defects, among which Class II defects represent a highly predictable scenario. Hence, regenerative periodontal therapy should be considered before resective therapy or extraction; 2) The application of a combined therapeutic approach (i.e., barrier, bone replacement graft with or without biologics) appears to offer an advantage over monotherapeutic algorithms; 3) To achieve predictable regenerative outcomes in the treatment of furcation defects, adverse systemic and local factors should be evaluated and controlled when possible; 4) Stringent postoperative care and subsequent supportive periodontal therapy are essential to achieve sustainable long-term regenerative outcomes.

The Nurturing of Seagliders By the National Oceanographic Partnership Program

The National Oceanographic Partnership Program provided critical support to the development of Seaglider long-range autonomous underwater vehicles. This support enabled: (1) development and integration of chemical and biological sensors, (2) transition to low-power, bi-directional satellite communication, and (3) software upgrades to enhance capability and reliability. Sponsored improvements led to setting the mission endurance and range records for autonomous underwater vehicles, wide use by the oceanographic community and licensing for commercialization.

An analysis of Texas's school based HPV vaccine mandate: A public health risk communication failure: HPVETO!

Genital human papillomavirus (HPV) is of public health concern because persistent infection with certain HPV types can cause cervical cancer. In response to a nationwide push for cervical cancer legislation, Texas Governor Rick Perry bypassed the traditional legislative process and issued an executive order mandating compulsory HPV vaccinations for all female public school students prior to their entrance in the sixth grade. By bypassing the legislative process Governor Perry did not effectively mitigate the risk perception issues that arose around the need for and usefulness of the vaccine mandate. This policy paper uses a social policy paradigm to identify perception as the key intervening factor on how the public responds to risk information. To demonstrate how the HPV mandate failed, it analyzes four factors, economics, politics, knowledge and culture, that shape perception and influence the public's response. By understanding the factors that influence the public's perception, public health practitioners and policy makers can more effectively create preventive health policy at the state level. ^

Mandating the HPV vaccine

Background. HPV is the underlying cause of cervical cancer, a malignant tumor of the female genital tract. Each year, cervical cancer is newly diagnosed in approximately 10,000 women, and over 3,000 women die from the malignancy. In addition, HPV is implicated as a cause of other cancers involving the genital tract, male and female, and the head and neck. ^ Gardasil, a vaccine against HPV, was licensed by the FDA in June 2006. Early study results have shown Gardasil to be safe and effective at preventing HPV infections that are commonly associated with the development of cervical cancer, as well as other HPV-related cancers and genital warts. The vaccine is most effective when administered in childhood, before initial exposure to HPV, which typically occurs shortly after the onset of sexual activity. Accordingly, the CDC's Advisory Committee on Immunization Practices (ACIP) has recommended routine vaccination of females aged 11-12 years. ^ Taking the ACIP recommendation one step further, many states have considered school-based mandates of the HPV vaccine in an attempt to reduce the burden of HPV-related illness, in particular to reduce the disparately high incidence of cervical cancer in medically underserved populations. These mandate attempts have sparked heated debate—highlighting public concerns regarding adolescent sexuality, corporate greed, and vaccines in general. ^ Methods. My research focuses on publicly available sources of information such as medical journals, government reports (federal and state), NGO reports, newspapers, and books. I begin with a background discussion of HPV, cervical cancer, and the HPV vaccine. I then discuss public health policy issues related to vaccines, vaccine mandates, and HPV-related illness. Specifically, I discuss the public health benefit of previous vaccine mandates, the legality of vaccine mandates, and the undue corporate influence on the politics of instituting HPV vaccine mandates. In addition, I examine some of the causes behind the anti-vaccine movement and the controversy surrounding adolescent sexuality as it pertains to the HPV vaccine. In the final section, I focus on the recent failed attempt by Governor Rick Perry to mandate the HPV vaccine in Texas. A retrospective analysis of Governor Perry's policy decisions is undertaken and recommendations are made regarding future attempts to mandate the HPV vaccine, or other vaccines under development for similar sexually transmitted viral diseases such as HIV and herpes simplex. ^ Results. In Texas, as in other states across the country, HPV vaccine mandates faced opposition from those who, while they may support mandates of other vaccines, oppose mandates for the HPV vaccine based largely on the idea that HPV is a sexually transmitted disease—they see responsible sexual behavior as the appropriate method for preventing HPV-related illness. A second major group of opposition comes from those who are generally opposed to all vaccine mandates, due to concerns that mandates are intended primarily for the financial benefit of the pharmaceutical industry or due to concerns—largely unfounded—that vaccines pose a greater health threat than the illnesses they are designed to prevent. ^ Conclusion. In order to reduce opposition to vaccine mandates, care must be taken to educate the public regarding the benefits of vaccination by mobilizing the public health sector, avoid the impression that the decision to institute mandates is rash or pressured by allowing time for open debate, and minimize lobbying efforts by vaccine manufacturers. ^