Book chapters will be unavailable on Saturday 24th August between 8am-12pm BST. This is for essential maintenance which will provide improved performance going forwards. Please accept our apologies for any inconvenience caused.
To send content items to your account,
please confirm that you agree to abide by our usage policies.
If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your account.
Find out more about sending content to .
To send content items to your Kindle, first ensure firstname.lastname@example.org
is added to your Approved Personal Document E-mail List under your Personal Document Settings
on the Manage Your Content and Devices page of your Amazon account. Then enter the ‘name’ part
of your Kindle email address below.
Find out more about sending to your Kindle.
Note you can select to send to either the @free.kindle.com or @kindle.com variations.
‘@free.kindle.com’ emails are free but can only be sent to your device when it is connected to wi-fi.
‘@kindle.com’ emails can be delivered even when you are not connected to wi-fi, but note that service fees apply.
Human alteration of the planet’s terrestrial landscapes for agriculture, habitation and commerce is reshaping wildlife communities. The threat of land cover change to wildlife is pronounced in regions with rapidly growing human populations. We investigated how species richness and species-specific occurrence of bats changed as a function of land cover and canopy (tree) cover across a rapidly changing region of Florida, USA. Contrary to our predictions, we found negligible effects of agriculture and urban development on the occurrence of all species. In contrast, we found that a remotely sensed metric of canopy cover on a broad scale (25 km2) was a good predictor of the occurrence of eight out of ten species. The occurrence of all smaller bats (vespertilionids) in our study increased with 0–50% increases in canopy cover, while larger bats showed different patterns. Occurrence of Brazilian free-tailed bats (Tadarida brasiliensis) decreased with increasing canopy cover, and Florida bonneted bats (Eumops floridanus) were not influenced by canopy cover. We conclude that remotely sensed measures of canopy cover can provide a more reliable predictor of bat species richness than land-cover types, and efforts to prevent the loss of bat diversity should consider maintaining canopy cover across mosaic landscapes with diverse land-cover types.
Background: Cervical sponylotic myelopathy (CSM) may present with neck and arm pain. This study investiagtes the change in neck/arm pain post-operatively in CSM. Methods: This ambispective study llocated 402 patients through the Canadian Spine Outcomes and Research Network. Outcome measures were the visual analogue scales for neck and arm pain (VAS-NP and VAS-AP) and the neck disability index (NDI). The thresholds for minimum clinically important differences (MCIDs) for VAS-NP and VAS-AP were determined to be 2.6 and 4.1. Results: VAS-NP improved from mean of 5.6±2.9 to 3.8±2.7 at 12 months (P<0.001). VAS-AP improved from 5.8±2.9 to 3.5±3.0 at 12 months (P<0.001). The MCIDs for VAS-NP and VAS-AP were also reached at 12 months. Based on the NDI, patients were grouped into those with mild pain/no pain (33%) versus moderate/severe pain (67%). At 3 months, a significantly high proportion of patients with moderate/severe pain (45.8%) demonstrated an improvement into mild/no pain, whereas 27.2% with mild/no pain demonstrated worsening into moderate/severe pain (P <0.001). At 12 months, 17.4% with mild/no pain experienced worsening of their NDI (P<0.001). Conclusions: This study suggests that neck and arm pain responds to surgical decompression in patients with CSM and reaches the MCIDs for VAS-AP and VAS-NP at 12 months.
Despite a recent increase in research on its sociopolitical implications, many questions regarding rap music’s influence on mass-level participation remain unanswered. We consider the possibility that “imagining a better world” (measured here as the degree to which young African Americans are critical of the music’s negative messages) can correlate with a desire to “build a better world” (operationalized as an individual’s level of political participation). Evidence from the Black Youth Project (BYP)’s Youth Culture Survey (Cohen 2005) demonstrates that rap critique exerts a conditional impact on non-voting forms of activism. Rap critique enhances heavy consumers’ civic engagement, but this relationship does not occur among Blacks who consume the music infrequently. By demonstrating rap’s politicizing power and contradicting certain criticisms of Hip Hop culture, our research celebrates the possibilities of Black youth and Black music.
To estimate the additional health and economic burden of antimicrobial-resistant (AMR) infections in Australian hospitals.
A simulation model based on existing evidence was developed to assess the additional mortality and costs of healthcare-associated AMR Escherichia coli (E. coli), Klebsiella pneumoniae, Pseudomonas aeruginosa, Enterococcus faecium, and Staphylococcus aureus infections.
Australian public hospitals.
Australian hospitals spent an additional AUD$5.8 million (95% uncertainty interval [UI], $2.2–$11.2 million) per year treating ceftriaxone-resistant E.coli bloodstream infections (BSI), and an estimated AUD$5.5 million per year (95% UI, $339,633–$22.7 million) treating MRSA patients. There are no reliable estimates of excess morbidity and mortality from AMR infections in sites other than the blood and in particular for highly prevalent AMR E. coli causing urinary tract infections (UTIs).
The limited evidence-base of the health impact of resistant infection in UTIs limits economic studies estimating the overall burden of AMR. Such data are increasingly important and are urgently needed to support local clinical practice as well as national and global efforts to curb the spread of AMR.
Elevated levels of organochlorines (OC) have been reported in Inuit populations in the Arctic. We hypothesized that prenatal exposure to a Canadian Arctic OC mixture adversely affects male reproductive function and health with age. Sprague–Dawley female rats (F0) were gavaged with an environmentally relevant concentration of an Arctic OC mixture or corn oil (Control) during mating with untreated males until parturition (F1 litters). After postnatal day (PND) 90, the weights of the OC F1 males differed dramatically relative to Controls (P<0.05; n=10) and they exhibited respiratory distress. Except for possible thinning of the alveolar barrier, histological observation of the lungs revealed no apparent pathology to explain the respiratory distress. At PND 365, OC F1 males had reduced relative reproductive organ weights and lower sperm quality than Controls (P<0.05). At PND 90, OC F1 males were subfertile (P<0.05), but were infertile at PND 365. In conclusion, environmentally relevant prenatal OC exposure reduced reproductive function and health in aging male rats, providing new insight into the effects of early-life exposures to these contaminants.
Teaching undergraduate students, mentoring graduate students, and generating publishable research are distinct tasks for many political scientists. This article highlights lessons for merging these activities through experiences from an initiative that sparked a series of collaborative-research projects focused on opinions about crime and punishment in the United States. This article describes three collaborative projects conducted between 2015 and 2017 to demonstrate how to merge undergraduate teaching, graduate training, and producing research. By participating in these projects, students learned about social-scientific research through hands-on experiences designing experiments, collecting and analyzing original data, and reporting empirical findings to a public audience. This approach is an effective way to engage students and generate research that can advance professional goals.
For more than 30 years the ‘two-process model’ has played a central role in the understanding of sleep/wake regulation. This ostensibly simple model is an interesting example of a non-smooth dynamical system, whose rich dynamical structure has been relatively unexplored. The two-process model can be framed as a one-dimensional map of the circle, which, for some parameter regimes, has gaps. We show how border collision bifurcations that arise naturally in maps with gaps extend and supplement the Arnold tongue saddle-node bifurcation set that is a feature of continuous circle maps. The novel picture that results shows how the periodic solutions that are created by saddle-node bifurcations in continuous maps transition to periodic solutions created by period-adding bifurcations as seen in maps with gaps.
Introduction: Laceration is common in children presenting to the emergency department (ED). They are often uncooperative related to pain and distressed during repair. Currently, there are wide variations regarding sedation and analgesia practices when sutures are required. There is a growing interest in the intranasal (IN) route for procedural sedation and pain control because of its effectiveness potential and ease of administration. Few studies have evaluated IN ketamine for procedural sedation in children with reported doses ranging from 3 to 9 mg/kg. The objective is to evaluate the optimal IN ketamine dose for effective and safe procedural sedation for laceration repair in children aged 1 to 12 years. Methods: A dose escalation clinical trial with an initial dose of 3 mg/kg of IN ketamine up to a maximum dose of 9 mg/kg in children 1 to 12 years old, using a 3+3 trial design. For each tested dose, 3 patients are enrolled. Escalation to the next dose is permitted if sedation is unsuccessful in at least one patient without serious adverse event (SAE). Regression to prior dose is warranted in the occurrence of two or more SEAs. This process is repeated until effective sedation for 6 patients at two consecutive doses is achieved with a maximum of 1 SAE or if regression occurs. The primary outcome is the optimal dose for successful procedural sedation as per the PERC/PECARN consensus criteria. Secondary outcome, namely, pain and anxiety levels, parent, patient and provider satisfaction, recovery time, length of stay in the ED, side effects and adverse event are recorded. Results: Nine patients have been recruited from March to December 2017 with median age of 2.9 years-old and with laceration length of 2 to 5 cm and with facial involvement in 55% of cases, respectively. Sedation was successful in 1/3, 1/3 and 3/3 of patients at doses of 3, 4, 5 mg/kg respectively, without any SAE. Median time from ketamine administration to return to baseline status and discharge were 35 and 98 min, respectively. We expect to complete patient recruitment in March 2018. Conclusion: The results from our trial is a groundwork for future dose-finding study. Pending study completion, a multicentric dose validation trial, is set up to further validate the optimal dose from dosINK1 trial. IN ketamine has the potential to improve the field of procedural sedation for children by introducing an effective IN agent with respiratory stability but without the need for an IV line insertion not otherwise needed.
Introduction: Despite revolutionary changes in the medical education landscape, journal club (JC) continues to be a ubiquitous pedagogical tool and is a primary way that residency programs review new evidence and teach evidence-based medicine. JC is a community of practice among physicians, which may help translate research findings into practice. Program representatives state that JC should have a goal of translating novel research into changes in clinical care, but there has been minimal evaluation of the success of JC in achieving this goal. Specifically, emergency medicine resident perspectives on the utility of JC remain unknown. Methods: We designed a multi-centre qualitative study for three distinct academic environments at the University of British Columbia (Vancouver, Victoria and Kelowna). Pilot testing was performed to generate preliminary themes and to finalize the interview script. An exploratory, semi-structured focus group was performed, followed by multiple one-on-one interviews using snowball sampling. Iterative thematic analysis directed data collection until thematic sufficiency was achieved. Analysis was conducted using a constructivist Grounded Theory method with communities of practice as a theoretical lens. Themes were compared to the existing literature to corroborate or challenge existing educational theory. Results: Pilot testing has revealed the following primary themes: (1) Only select residents are able to increase their participation in JC over the course of residency and navigate the transition from peripheral participant to core member; (2) These residents use their increased clinical experience to perceive relevance in JC topics, and; (3) Residents who remain peripheral participants identify a lack time to prepare for journal club and a lack of staff physician attendance as barriers to resident engagement. We will further develop these themes during the focus group and interview phases of our study. Conclusion: JC is a potentially valuable educational resource for residents. JC works as a community of practice only for a select group of residents, and many remain peripheral participants for the duration of their residency. Incorporation of Free Open-Access Medical Education resources may also decrease preparation time for residents and staff physicians and increase buy-in. To augment clinical impact, the JC community of practice may need to expand beyond emergency medicine and include other specialties.
The epitheliochorial placenta of the pig does not allow the passage of immunoglobulin to the foetus and thus the young piglet is born without passive immune protection. During the first 36 h of life there is a massive transmission of macromolecules across the intestine, virtually all that are present in the gut may be effectively endocytosed and transmitted into the blood stream. The postnatal transmission of antibody from colostrum during this period provides the young animal with a spectrum of serum antibodies indistinguishable from that of its mother. It is established that even in utero the piglet is capable of mounting some response to antigenic challenge. Despite this, the ability of the young animal to respond may be influenced profoundly by the absorption of macromolecules (antibodies and antigens in colostrum and in sow's milk as well as antigens in the farrowing house) during the first hours after birth. These effects range from passive protection from infectious agents during the neonatal period to determining the precise nature of the immune response to antigens during later periods (e.g. at weaning).
At birth all cellular components of the immune system are represented but during the first few weeks of life dramatic changes occur in the number and distribution of these cells. Our histological studies have shown that shortly after birth the predominant T lymphocytes in the small intestine are T2+, T4− and T8−; whilst in other organs there are large numbers of conventional T4+ and T8+ cells. By 1 week of age there is a dramatic increase in the numbers of T4+ cells, whilst T8+ cells remain low, and only start to increase by week 7. Thus, changes in lymphocyte populations are occurring concurrent with increasing exposure to environmental antigens. The functional capacity of these cells also changes during this period and this process may be particularly affected by early weaning.
During the neonatal period an animal is presented with a vast array of antigenic material for the first time. How and when these antigens are presented may profoundly influence the capacity of the immune system to respond to them.
The role played by the Arabian Peninsula in hominin dispersals out of Africa has long been debated. The DISPERSE Project has focused on south-western Arabia as a possible centre of hominin settlement and a primary stepping-stone for such dispersals. This work has led to the recent discovery, at Wadi Dabsa, of an exceptional assemblage of over 1000 lithic artefacts, including the first known giant handaxe from the Arabian Peninsula. The site and its associated artefacts provide important new evidence for hominin dispersals out of Africa, and give further insight into the giant handaxe phenomenon present within the Acheulean stone tool industry.