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The benefit of mandibular advancement devices in patients with sleep-disordered breathing and as a potential option for obstructive sleep apnoea syndrome is well recognised. Their use in the setting of epilepsy or other seizure disorders is typically contraindicated.
A 48-year-old patient with a history of poorly controlled epilepsy and obstructive sleep apnoea syndrome was referred for ENT review for possible tracheostomy. The patient was wheelchair-bound with 24-hour continuous positive airway pressure, but sleep studies demonstrated persistent, severe episodes of apnoea and notable sleep disturbance. Sleep nasendoscopy demonstrated marked improvement on capnography with the laryngeal mask airway in situ, and this was maintained with mandibular advancement using jaw thrust following removal of the laryngeal mask airway. A mandibular advancement device was subsequently trialled; this had no subjective benefit for the patient, but the seizures resolved and control of apnoea was achieved with the combination of a mandibular advancement device and continuous positive airway pressure.
This paper highlights a novel application of mandibular advancement devices, used in combination with continuous positive airway pressure, which resulted in complete resolution of sleep deprivation and apnoea-induced epileptic events.
Smoking is a well-established risk factor for dementia, but the effects of passive smoking are unclear. We aimed to examine links between passive smoking and dementia or cognitive impairment.
We searched seven medical research databases: MEDLINE, Web of Science (Core Collection), Cochrane, EMBASE, PsycINFO, Scopus, and CINAHL Plus. Studies were included if they examined measures of passive smoking and either cognitive impairment or dementia.
Of 1,425 records found, nine papers of varying methodologies were included after screening against inclusion criteria. Eight papers reported weak associations between passive smoking and either cognitive impairment or dementia. One paper only found this association alongside carotid artery stenosis. The papers’ quality was variable, with only two deemed high quality.
There is limited weak observational evidence linking passive smoking with an increased risk of cognitive impairment or dementia. However, the studies were methodologically diverse and of inconsistent quality, preventing firm conclusions.
We examine time series of the transition region spectral line O v 629 Å, observed with the Coronal Diagnostic Spectrometer (CDS) onboard the SoHO spacecraft. Primarily we were looking for intensity and velocity oscillations in polar plumes, however by chance we detected a giant macro-spicule at the limb and were able to follow its dynamical structure. We have reported the dynamics of the giant macro-spicule in Banerjee et al. (2000a) and have also reported the existence of long period oscillations in the polar plumes as observed in the O v 629 Å line in Banerjee et al. (2000a,b). In this short contribution we revisit one of these dataset, namely s16834r01 to test the reliability of the observed periods. The statistical significance of the oscillations is estimated by using a randomisation method. Our analysis re-confirms the presence of compressional waves with periods of 20-25 minutes.
Impending malignant spinal cord compression (IMSCC) may be defined as compression of the thecal sac, without any visible pressure on the spinal cord itself. Although there is a perception that IMSCC patients have a better prognosis and less severe clinical symptoms than true malignant spinal cord compression (MSCC) patients, these factors have never been documented in the literature.
To record the characteristics, management and functional outcome of a group of patients with IMSCC, who were treated with radiotherapy in our institution, and compare these parameters with similar data on MSCC patients.
Materials and methods
Data (gender, age, primary oncological diagnosis, pain, performance status and neurological status) were prospectively collected for 28 patients. Patients were then followed up post treatment to document their response to treatment and treatment-related toxicity.
The median survival of our group of IMSCC patients is similar to that of an MSCC patient. In addition, the IMSCC group exhibits significant clinical symptoms including neurological deficit.
Although further studies are necessary, we have found that IMSCC patients in this study share similar prognosis and clinical symptoms with MSCC patients. Clinicians should be aware of this when communicating with IMSCC patients and their families, and short-course radiotherapy should be considered.
The paper provides new estimates of dementia prevalence at a national and local level in Ireland and new projections of future numbers of people with dementia.
The prevalence of dementia at a national and local level has been calculated by applying European Collaboration on Dementia (EuroCoDe) prevalence rates to data from the Census of Population 2006. The National Disability Survey has been used to estimate the number of people with Down syndrome and dementia. Projections of future numbers of people with dementia have been calculated by applying EuroCoDe prevalence rates to the most recently available population projections from the Central Statistics Office (CSO).
It is estimated that there were 41 740 people with dementia in Ireland in 2006. Estimates show that there are clear regional differences in prevalence of dementia across Ireland, with the largest proportion of people with dementia in the West of Ireland, and the Dublin North Eastern region having the lowest share of dementia. Our best estimate is that there are 700 people with Down syndrome and dementia in Ireland. Applying EuroCoDe prevalence rates to the most recent CSO population projections shows that the prevalence of dementia in Ireland will increase to between 67 493 and 70 000 in 2021 and to between 140 580 and 147 000 in 2041.
Although there are several limitations to these estimates, the data provide timely and useful information for planning effective health and social care services, as well as raising public and professional awareness about dementia at a national level.
This book was born out of passion, frustration, excitement and hope. Readers will perceive all these emotions throughout the following pages. If the hard-won lessons recounted here lead to improved conservation of some remarkable species and their ecosystems, we will have fulfilled our aim.
We have cumulatively spent well over a century studying the various members of the Order Sirenia. Our passions include learning about and trying to conserve manatees and dugongs. The word ‘unique’ has lost its force through inaccuracy and over-use, but we want to reclaim its original meaning here. The sirenians possess suites of morphological, ecological and physiological adaptations that allow them, truly, to hold a unique place in the animal kingdom. Although once a more diverse group, the sirenians are limited now to only four species, albeit with remarkably wide geographic ranges (especially the dugong). Reduced in numbers through much of that range, and with myriad threats to their long-term survival, the sirenians have nonetheless demonstrated tenacity and resilience, hopeful signs that they will persist, if given a chance.
Understanding the conservation status of species is very important because it is an indicator of the likelihood of their continuing to exist. In this chapter we first review the criteria used for designating the conservation status of sirenians. We then provide an overview of the methods used for estimating abundance and trends in population sizes. The remainder of the chapter provides an updated summary of findings and our assessment of the status of the extant sirenians. This assessment includes reviews of their status under various international agreements, population sizes and trends, major threats and pertinent conservation impediments and actions.
Criteria for Designating Conservation Status
The IUCN Red List of Threatened Species (Red List) produced by the Species Survival Commission (SSC) of the International Union for Conservation of Nature (IUCN) is the best-known global conservation status listing and ranking system (IUCN 2009). In 2005 the World Conservation Congress passed a resolution mandating the use of the Red List for national legislation, international conventions, conservation planning and scientific research (IUCN 2005).
As explained in Chapter 3, sirenians evolved from primitive terrestrial herbivores early in the Tertiary period. Like whales and dolphins (cetaceans) but unlike the pinnipeds (walruses, seals and sea lions), manatees and dugongs spend their entire lives in the water and do not return to land to give birth and suckle their young. Sirenians are believed to share a common origin with several superficially dissimilar mammals of African origin, grouped together at the superordinal level as the Afrotheria. Within the Afrotheria the sirenians are closely aligned with elephants and hyraxes, and the three have been linked together as the clade Paenungulata, a unique grouping recognised for most of the last century (see Chapter 3). Although features of the external form of sirenians reflect adaptations to their lives of swimming and diving, the phylogenetic history of dugongs and manatees is reflected in features of their reproductive biology, which in some respects is strikingly similar to that of elephants (as outlined under ‘Reproductive cycles’ below and in the Supplementary Material Appendix 6.1).
Understanding the life history and reproductive biology of sirenians is fundamental to the development of effective strategies for their conservation. For example, knowledge of when and where they breed is important for assessing the effectiveness of establishing sanctuaries or other protected areas to protect breeding habitat. In addition, knowledge of the mating system (Chapter 5), the average ages at which females start breeding, the litter size, average inter-birth interval, life span and the probabilities of reproduction and survival, and how these parameters are affected by age and changing environmental conditions, are essential for understanding the population dynamics of manatees and dugongs. Knowledge of population dynamics is a requisite for sound management policies and for estimating the levels of human-induced mortality that are likely to be sustainable. In this chapter, we characterise the biology of reproduction in the Sirenia, and describe the methodological and analytical approaches that have been taken over the years to determine their vital parameters of reproduction and survival. We summarise the results of these studies and then review how information about vital parameters has been incorporated into models of sirenian population dynamics and the implications of these models for future research and management.
In 2008 a US federal court judge ruled that the Defense Department’s plans to construct an offshore marine airbase on the island of Okinawa, Japan contravened the US National Historic Preservation Act of 1966 (Tanji 2008). The rationale for the court’s decision, known as Dugong v. Gates, was that construction plans for the base failed to protect the dugong, one of the animals that are the subjects of this book. The dugong is listed as critically endangered by the Japanese Ministry of the Environment and as a National Monument on the Japanese Register of Cultural Properties because of its high cultural value to the people of Okinawa. In 2005 a companion court case (Dugong v. Rumsfeld) had established the legitimacy of declaring an animal to be a historically significant ‘property’ under US legislation, ensuring that the US National Historic Preservation Act of 1966 applied.
The outcome of these court cases does not guarantee the future of the dugong in Japan, where it is subject to multiple threats in addition to the airbase (Marsh et al. 2002; Ikeda and Mukai 2012; Chapter 8). Indeed, the court decision seems unlikely to prevent the construction of the airbase.
As discussed in Chapters 3–6, manatees and dugongs are long-lived, slow breeding, aquatic herbivores with a low metabolic rate. This life history means that their populations are sensitive to both mortality, especially adult mortality, and habitat loss. Dugongs and manatees are subject to a range of threats (Chapter 7), the relative importance of which varies with location and particularly whether the range state is a developed or developing country. The capacity of a country to implement effective conservation actions also varies with its developmental stage; in general, developing countries are likely to have a lower capacity to implement effective conservation than developed countries (Leverington et al. 2008; Table 8.9).
Our review of sirenian research (Chapters 3–6) is largely based on Florida manatees and Australian dugongs, because those populations are the ones that have provided the bulk of our knowledge. Ironically, these are among the sirenian populations most likely to persist (Table 8.9). This situation is not a coincidence, as extensive scientific information can inform effective conservation decisions. However, as noted in Chapter 1 and by Reynolds et al. (2009), lack of science is not the primary factor that is preventing the conservation of sirenians and other marine mammals. Indeed, developing tropical nations should not wait for science at the pace and sophistication of the developed world before implementing conservation actions. Rather, the science learned elsewhere in broad outline will be for the most part transferable to conservation of Trichechus senegalensis, T. inunguis, T. m. manatus and most populations of dugongs, as assumed in the sirenian conservation primer by Hines et al. (2012b).
The culmination of the evolution of the hydrodamaline lineage in the North Pacific Ocean that began in the Miocene (Chapter 3) ended abruptly in historic times. Hydrodamalis gigas, once distributed widely around the region, was restricted to coastal fringes of two islands near the Kamchatka Peninsula of Siberia, where it was discovered by Europeans in the middle of the eighteenth century. This magnificent, though bizarre, beast was quickly exploited for its meat to supply workers in the expanding fur trade, and could not hold out for long after it was found. Perhaps typical of its time, this exploitation was wasteful and opportunistic. Given the restricted distribution, limited population and likely low rates of potential population growth (see Chapter 6 for discussion of life histories of extant sirenians), the pressures of exploitation could only be withstood by H. gigas for some 27 years before it was rendered extinct. This extinction was a great loss of a biological treasure, and is sometimes cited as a warning of the vulnerability of sirenian populations (among others) to over-exploitation. In appreciation of the uniqueness of this animal, and of the importance of the lesson its loss teaches us, we highlight the historical background to its discovery during a truly epic voyage; describe the demise of the last population; and provide a summary of both historical and modern findings regarding its biology. Over the years, previous authors have also given accounts of the sea cow’s discovery and extirpation (e.g. Goodwin 1946; Scheffer 1973; Haley 1980; Reynolds and Odell 1991; Dietz 1992; Anderson and Domning 2002). However, only one scientist ever observed and dissected Hydrodamalis gigas, and so throughout this chapter we provide the reader with excerpts of Steller’s descriptions through direct translations of his own words rather than attempt to interpret them anew.
Georg Wilhelm Steller and the Voyage of the St Peter
Steller’s sea cow (Hydrodamalis gigas) was named for Georg Wilhelm Steller, the only scientist ever to observe this extraordinary animal alive. He discovered a relict population of the giant sirenian when he was stranded with crew mates on an uninhabited island in the eastern Bering Sea in 1741. Steller was an excellent scientist of his time, particularly in botany, and was physically strong and well-suited to the spartan life of a frontier naturalist (Stejneger 1936). He was born in 1709 in Germany, where his university education emphasised theology, anatomy, medicine and botany (he eventually lectured in the last of these). His early career took him to Russia, where he changed the spelling of his name (originally Stöhler or Stöller) to better suit the Russian language (Stejneger 1936). Steller received an appointment from the Academy of Sciences at St Petersburg, which sent him to the Kamchatka Peninsula of far eastern Siberia as a botanist. Soon thereafter he joined the second expedition of Vitus Bering (for whom the Bering Sea is named) on which he served as naturalist, physician and pastor. Captain-Commander Bering was a Dane, commissioned by Peter the Great to explore passages at the eastern frontiers of Russia and beyond to North America. The expedition sailed from Kamchatka in two ships, the St Peter and the St Paul (Figure 2.1).
The feeding biology of sirenians, the only group of fully aquatic herbivorous mammals, is arguably their most defining characteristic and the basis for their popular name – sea cows. In this chapter, we describe the feeding biology of wild populations of the four species of extant sirenians and the methods used to obtain this information. We then explore the significance of this information for sirenian conservation. We have not considered the feeding biology of captive sirenians, which is discussed by various authors, especially Best (1981) and Marshall et al. (1998, 2000, 2003), or the feeding biology of Steller’s sea cow and other extinct sirenians, which are discussed in Chapters 2 and 3.
Optimal Foraging Theory
MacArthur and Pianka (1966) and Emlen (1966) first articulated the theory of optimal foraging, which states that natural selection favours animals whose behavioural strategies maximise their net energy intake per unit time spent foraging. Foraging time includes both the time spent searching for food and the time spent handling food. The theory was devised to attempt to explain why, out of the wide range of foods available, animals often restrict themselves to a few preferred types. The theory is based on assumptions that may not apply to wild animals and is contentious (e.g. Pyke 1984; Pierce and Ollason 1987), but provides a useful heuristic framework for considering the trade-offs that sirenians have to make as they go about their daily lives.
Dugongs and manatees, the only fully aquatic herbivorous mammals, live in the coastal waters, rivers and lakes of more than 80 subtropical and tropical countries. Symbols of fierce conservation battles, sirenian populations are threatened by multiple global problems. Providing comparative information on all four surviving species, this book synthesises the ecological and related knowledge pertinent to understanding the biology and conservation of the sirenia. It presents detailed scientific summaries, covering sirenian feeding biology; reproduction and population dynamics; behavioural ecology; habitat requirements and threats to their continued existence. Outlining the current conservation status of the sirenian taxa, this unique study will equip researchers and professionals with the scientific knowledge required to develop proactive, precautionary and achievable strategies to conserve dugongs and manatees. Supplementary material is available online at: www.cambridge.org/9780521888288.