121 research outputs found
An Albino Muskox near the Atkinson Point River, Northwest Territories
Gavin during his stay near the mouth of the Perry River (67°48'N, 102°16'W) from 1937-1941 reported only few muskoxen. The largest herds were 12 and 15, seen in 1938 on the mainland a few miles west of the mouth of the Perry River. Aleksiuk saw no muskoxen during his period of field work in the Perry River area from 21 May to 10 August 1963 but reported that, according to local Eskimos, muskoxen were still found in the region of MacAlpine Lake, at the headwaters of Perry River. During waterfowl surveys on 11, 15, and 16 August 1971, between Perry River and the Atkinson Point River (103°18'W) and between 67°10'N and 67°45'N we saw the following numbers of muskoxen: 1, 26, 48, 1, 1, 23, 16, 1, 1. Dates of observation of herds, their location and numbers of yearlings preclude the possibility of duplication. Of particular interest was the occurrence of a light-coloured individual in the herd of 23 observed on 15 August along the Atkinson Point River at 67°45'N, 103°18'W. The animal in question was a large adult of a pale creamy-yellow colour. Photographs taken at the time show the animal to be accompanied by a yearling of normal colouration. At first the pale-coloured individual was thought to be a bull but the persistent proximity of the yearling and the adult's behaviour in running at the forefront of the herd when chased (in opposition to bulls which normally follow the herd) suggested that the muskox in question was a cow.... We were unable to get a good look at the cow's horns but they appeared paler than in muskoxen having the typical pelage; just then we had run into low cloud and rain and were in fact retreating to our camp on the Perry River. Only one albino muskox has been recorded previously. Tener quotes McDougall's observation of an adult albino cow muskox on 18 June 1853 at Cape Smyth, Melville Island. That cow was followed by a black calf
Riboflavin-responsive complex I deficiency
Three patients from a large consanguineous family, and one unrelated patient had exercise intolerance since early childhood and improved by supplementation with a high dosage of riboflavin. This was confirmed by higher endurance power in exercise testing. Riboflavin had been given because complex I, which contains riboflavin in FMN, one of its prosthetic groups, had a very low activity in muscle. Histochemistry showed an increase of subsarcolemmal mitochondria. The low complex I activity contrasted with an increase of the activities of succinate dehydrogenase, succinate-cytochrome c oxidoreductase and cytochrome c oxidase. Isolated mitochondria from these muscle specimens proved deficient in oxidizing pyruvate plus malate and other NAD+-linked substrates, but oxidized succinate and ascorbate at equal or higher levels than controls. Two years later a second biopsy was taken in one of the patients, and the activity of complex I had increased from 16% to 47% of the average activity in controls. In the four biopsies, cytochrome c oxidase activity correlated negatively with age. We suspect that this is due to reactive oxygen species generated by the proliferating mitochondria and peroxidizing unsaturated fatty acids of cardiolipin. Three of the four patients had low blood carnitine, and all were found to have hypocarnitinemic family members
Practical tips and tricks in measuring strain, strain rate and twist for the left and right ventricles.
Strain imaging provides an accessible, feasible and non-invasive technique to assess cardiac mechanics. Speckle tracking echocardiography (STE) is the primary modality with the utility for detection of subclinical ventricular dysfunction. Investigation and adoption of this technique has increased significantly in both the research and clinical environment. It is therefore important to provide information to guide the sonographer on the production of valid and reproducible data. The focus of this review is to (1) describe cardiac physiology and mechanics relevant to strain imaging, (2) discuss the concepts of strain imaging and STE and (3) provide a practical guide for the investigation and interpretation of cardiac mechanics using STE
The use of virtual reality and augmented reality to enhance cardio-pulmonary resuscitation: a scoping review.
Background and objective Virtual reality (VR) and augmented reality (AR) have been proposed as novel methods to enhance cardio-pulmonary resuscitation (CPR) performance and increase engagement with CPR training. A scoping review was conducted to map the global evolution of these new approaches to CPR training, to assess their efficacy and determine future directions to meet gaps in current knowledge. Methods A standardised five-stage scoping methodology was used to (1) identify the research question, (2) identify relevant studies, (3) select the studies, (4) chart the data and (5) summarise the findings. The Kirkpatrick model levels of evidence were used to chart and assess the efficacy of each intervention reported. A multi-pronged search term strategy was used to search the Web of Science, PubMed, CINAHL and EMBASE databases up to June 2020. Results A total of 42 articles were included in this review. The first relevant paper identified was published in 2009 and based on VR, from 2014 onwards there was a large increase in the volume of work being published regarding VR and AR uses in CPR training. This review reports Kirkpatrick level one to three evidence for the use of VR/AR–CPR. Inconsistencies in the specific language, keywords used and methodologies are highlighted. Conclusion VR and AR technologies have shown great potential in the area of CPR, and there is continuing evidence of new novel applications and concepts. As VR/AR research into CPR reaches an inflection point, it is key to bring collaboration and consistency to the wider research community, to enable the growth of the area and ease of access to the wider medical community
Revisiting the Historic Distribution and Habitats of the Whooping Crane
Understanding the historic range and habitats of an endangered species can assist in conservation and reintroduction efforts for that species. Individuals reintroduced into a species’ historic core range have a higher survival rate compared to individuals introduced near the periphery or outside the historic range (Falk and Olwell, 1992; Griffith et al., 1989). Individuals on the periphery of a species’ range tend to occupy less favorable habitats and have lower and more variable densities than those near the core of their range (Brown, 1984; Brown et al., 1995, 1996). Such conclusions, however, presume that historic habitats have not changed since a species was extirpated from core areas – a difficult assumption for many areas, and particularly for wetland habitat (Prince, 1997). Many endangered species persist only on the periphery of their historic range because of habitat loss or modification in their core range (Channell and Lomolino, 2000), which can bias our understanding of the species’ habitat preferences. Further, habitat models based on locations where species persist necessarily emphasize local conditions rather than historical conditions (Kuemmerle et al., 2011). For example, habitat models for the European bison (Bison bonasus) suggested it was a woodland species, but assessment of the bison’s historic range indicated it preferred mosaictype landscapes and had a more eastern and northern distribution than previously reported (Kuemmerle et al., 2011, 2012). Hence, accurate determination of the historic range and habitat conditions for endangered species can improve our understanding of their ecology and assist in conservation and reintroduction efforts. Examining the historic range from an ecological perspective can also help identify where appropriate habitat still exists that could sustain a population
A Dutch Fanconi Anemia FANCC Founder Mutation in Canadian Manitoba Mennonites
Fanconi anemia (FA) is a recessive DNA instability disorder associated with developmental abnormalities, bone marrow failure, and a predisposition to cancer. Based on their sensitivity to DNA cross-linking agents, FA cells have been assigned to 15 complementation groups, and the associated genes have been identified. Founder mutations have been found in different FA genes in several populations. The majority of Dutch FA patients belongs to complementation group FA-C. Here, we report 15 patients of Dutch ancestry and a large Canadian Manitoba Mennonite kindred carrying the FANCC c.67delG mutation. Genealogical investigation into the ancestors of the Dutch patients shows that these ancestors lived in four distinct areas in The Netherlands. We also show that the Dutch and Manitoba Mennonite FANCC c.67delG patients share the same haplotype surrounding this mutation, indicating a common founder
Mortality in Aransas-Wood Buffalo Whooping Cranes: Timing, Location, and Causes
The Aransas-Wood Buffalo Population (AWBP) of Whooping Cranes (Grus americana) has experienced a population growth rate of approximately 4% for multiple decades (Butler et al., 2014a; Miller et al., 1974). Population growth for long-lived species of birds is generally highly sensitive to variation in adult mortality rates (Sæther and Bakke, 2000). A population model for endangered Red-crowned Cranes (Grus japonensis) in Japan conforms to this pattern, where growth rate is most sensitive to adult mortality (Masatomi et al., 2007). Earlier analyses observed that the AWBP growth rate increased in the mid-1950s and that this increase was likely caused by reduced annual mortality rates, even while the population experienced slightly decreasing natality (Binkley and Miller, 1988; Miller et al., 1974). A more contemporary analysis of the AWBP determined that approximately 50% of variation in annual population growth could be explained by variation in annual mortality (Butler et al., 2014a). Therefore, as a vital rate, mortality is critical to the maintained growth of the AWBP
A red knot as a black swan:How a single bird shows navigational abilities during repeat crossings of the Greenland Icecap
Despite the wealth of studies on seasonal movements of birds between southern nonbreeding locations and High Arctic breeding locations, the key mechanisms of navigation during these migrations remain elusive. A flight along the shortest possible route between pairs of points on a sphere ('orthodrome') requires a bird to be able to assess its current location in relation to its migration goal and to make continuous adjustment of heading to reach that goal. Alternatively, birds may navigate along a vector with a fixed orientation ('loxodrome') based on magnetic and/or celestial compass mechanisms. Compass navigation is considered especially challenging for summer migrations in Polar regions, as continuous daylight and complexity in the geomagnetic field may complicate the use of both celestial and magnetic compasses here. We examine the possible use of orientation mechanisms during migratory flights across the Greenland Icecap. Using a novel 2 g solar-powered satellite transmitter, we documented the flight paths travelled by a female red knotCalidris canutus islandicaduring two northward and two southward migrations. The geometry of the paths suggests that red knots can migrate across the Greenland Icecap along the shortest-, orthodrome-like, path instead of the previously suggested loxodrome path. This particular bird's ability to return to locations visited in a previous year, together with its sudden course changes (which would be appropriate responses to ambient wind fields), suggest a map sense that enables red knots to determine location, so that they can tailor their route depending on local conditions
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