We use cookies to distinguish you from other users and to provide you with a better experience on our websites. Close this message to accept cookies or find out how to manage your cookie settings.
To save 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 saving content to .
To save content items to your Kindle, first ensure no-reply@cambridge.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 saving to your Kindle.
Note you can select to save to either the @free.kindle.com or @kindle.com variations.
‘@free.kindle.com’ emails are free but can only be saved 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.
Rallidae are frequent colonists of oceanic islands and are often susceptible to introduced predators. The Tristan Moorhen Gallinula nesiotis was endemic to Tristan da Cunha, South Atlantic and is thought to have gone extinct in the late nineteenth century. The closely related Gough Moorhen G. comeri was introduced to Tristan da Cunha from neighbouring Gough Island in 1956. We report historical records of their spread across Tristan da Cunha and the results of a population survey undertaken in February–March 2024. Gough Moorhens are now found across the entire island wherever there is suitable habitat from sea level to above 900 m elevation. Gough Moorhens prefer fern bush habitat on the Base, the plateau above the steep coastal cliffs. The total population is approximately 41,500 birds (95% confidence interval 24,000–72,000). Our density estimates (3–6 birds/ha) are similar to estimates for Gough Moorhens on Gough Island before the post-2021 population decline and are at the higher end of densities reported for oceanic island rallids, suggesting that the Tristan da Cunha population may be near carrying capacity.
Rapid blood culture identification is most effective with antimicrobial stewardship feedback, which is limited during non-business hours. We implemented overnight review of Blood Culture Identification 2 panel results by intensive care unit pharmacists and demonstrated reduced time to evaluation (3.6 vs 9.3 hours, P < .01).
To understand healthcare workers’ (HCWs) beliefs and practices toward blood culture (BCx) use.
Design:
Cross-sectional electronic survey and semi-structured interviews.
Setting:
Academic hospitals in the United States.
Participants:
HCWs involved in BCx ordering and collection in adult intensive care units (ICU) and wards.
Methods:
We administered an anonymous electronic survey to HCWs and conducted semi-structured interviews with unit staff and quality improvement (QI) leaders in these institutions to understand their perspectives regarding BCx stewardship between February and November 2023.
Results:
Of 314 HCWs who responded to the survey, most (67.4%) were physicians and were involved in BCx ordering (82.3%). Most survey respondents reported that clinicians had a low threshold to culture patients for fever (84.4%) and agreed they could safely reduce the number of BCx obtained in their units (65%). However, only half of them believed BCx was overused. Although most made BCx decisions as a team (74.1%), a minority reported these team discussions occurred daily (42.4%). A third of respondents reported not usually collecting the correct volume per BCx bottle, half were unaware of the improved sensitivity of 2 BCx sets, and most were unsure of the nationally recommended BCx contamination threshold (87.5%). Knowledge regarding the utility of BCx for common infections was limited.
Conclusions:
HCWs’ understanding of best collection practices and yield of BCx was limited.
The negative predictive value of blaCTX-M on BCID2 for ceftriaxone resistance in E. coli and K. pneumoniae group was 97% and 94%, respectively. Creation of a genotypic antibiogram led to updated local guidance for clinicians to utilize for empiric treatment of Enterobacterales bloodstream infections identified via rapid diagnostics.
Behavior is the product of interconnected brain regions that work together as networks. This case study examines whether there are differences between a participant with a large congenital left temporal lobe cyst, which impacted the volume of structures in the region, and control subjects of similar age on cognitive tasks and network connectivity as measured by resting-state functional magnetic resonance imaging (rs-fMRI).
Participants and Methods:
The case participant (CP; 71 year old female) and controls (CON; n = 25; 48% female) were recruited as part of a larger aging study. CON were chosen from the larger study population by age (+/- 10 years from CP; Range = 68-86 years). Cognitive tasks included: Shopping list memory task, Montreal Cognitive Assessment, WAIS-IV subtests: Digit Span, Digit-Symbol, Symbol Span, and Letter-Number Sequencing. For rs-fMRI, we administered four blood-oxygen level dependent (BOLD) functional connectivity (rs-fMRI) scans at 6 minutes each. Image processing was conducted using the CONN toolbox. Independent sample t-tests evaluated differences between CP and CON. Segregation was evaluated in the Auditory (Au), Cerebellar-basal ganglia (CBBG), Cingulo-Opercular Task Control (COTC), Dorsal Attention (DA), Default Mode (DMN), Fronto-Parietal Task Control (FPTC), Salience (Sa), Sensory Somatomotor Hand (SSH), Sensory Somatomotor Mouth (SSM), Visual (Vi), and Ventral Attention (VA) networks to assess CP’s functional segregation by network throughout the brain. Bonferroni correction was applied to account for multiple comparisons in cognitive testing (.05/7 for significance at p < 0.007) and network segregation (.05/11 for significance at p < .005).
Results:
Independent samples t-tests did not reveal significant differences across cognitive tasks (t(24) <1.04, p > .05). Network segregation did not reveal significant differences between CP and CON across networks examined (t(24) < 1.269, p > .005). However, DMN and DA segregation trended toward significance (t(24) = -2.724, p = .006 and t(24) =-2.006, p = .028), respectively) with CP demonstrating lower segregation as compared to CON.
Conclusions:
CP performed similarly on cognitive testing to CON, indicating that the congenital presence of a large temporal lobe cyst did not impact global cognition, list learning and memory, working memory, or processing speed. CP did not demonstrate significantly different segregation across networks of interest after Bonferroni correction. Our cognitive performance results are consistent with a similar case-study examining language, which revealed intact linguistic abilities (Tuckete et al., 2022). The lack of differences in cognitive performance and segregation highlight the capacity for plasticity in the human brain, even in the presence of a large structural abnormality. This also suggests that the processes of aging in this case are not markedly different from controls. In future research we intend to expand on this case study by evaluating right temporal to hippocampal seeds and language network seeds to delve deeper into memory and language functioning.
In 21 antimicrobial stewardship programs in critical-access hospitals in Nebraska and Iowa that self-reported nonadherence to a CDC Core Element or Elements, in-depth program assessment and feedback revealed that accountability and education most needed improvement. Recommendations included providing physician and pharmacist training, tracking interventions, and providing education. Program barriers included lack of time and/or personnel and antimicrobial stewardship and/or infectious diseases expertise.
We compared the individual-level risk of hospital-onset infections with multidrug-resistant organisms (MDROs) in hospitalized patients prior to and during the coronavirus disease 2019 (COVID-19) pandemic. We also quantified the effects of COVID-19 diagnoses and intrahospital COVID-19 burden on subsequent MDRO infection risk.
Design:
Multicenter, retrospective, cohort study.
Setting:
Patient admission and clinical data were collected from 4 hospitals in the St. Louis area.
Patients:
Data were collected for patients admitted between January 2017 and August 2020, discharged no later than September 2020, and hospitalized ≥48 hours.
Methods:
Mixed-effects logistic regression models were fit to the data to estimate patients’ individual-level risk of infection with MDRO pathogens of interest during hospitalization. Adjusted odds ratios were derived from regression models to quantify the effects of the COVID-19 period, COVID-19 diagnosis, and hospital-level COVID-19 burden on individual-level hospital-onset MDRO infection probabilities.
Results:
We calculated adjusted odds ratios for COVID-19–era hospital-onset Acinetobacter spp., P. aeruginosa and Enterobacteriaceae spp infections. Probabilities increased 2.64 (95% confidence interval [CI], 1.22–5.73) times, 1.44 (95% CI, 1.03–2.02) times, and 1.25 (95% CI, 1.00–1.58) times relative to the prepandemic period, respectively. COVID-19 patients were 4.18 (95% CI, 1.98–8.81) times more likely to acquire hospital-onset MDRO S. aureus infections.
Conclusions:
Our results support the growing body of evidence indicating that the COVID-19 pandemic has increased hospital-onset MDRO infections.
In September 2021, a cluster of 6 patients with nosocomial coronavirus disease 2019 (COVID-19) were identified in a transplant unit. A visitor and 11 healthcare workers also tested positive for severe acute respiratory coronavirus virus 2 (SARS-CoV-2). Genomic sequencing identified 3 separate introductions of SARS-CoV-2 with related transmission among the identified patients and healthcare workers.
To evaluate the need for mandatory infectious diseases consultation (IDC) for candidemia in the setting of antimicrobial stewardship guidance.
Design:
Retrospective cohort study from January 2016 to December 2019.
Setting:
Academic quaternary-care referral center.
Patients:
All episodes of candidemia in adults (n = 92), excluding concurrent bacterial infection or death or hospice care within 48 hours.
Methods:
Primary outcome was all-cause 30-day mortality. Secondary outcomes included guideline-adherence and treatment choice. Guideline-adherence was assessed with the EQUAL Candida score.
Results:
Of 186 episodes of candidemia, 92 episodes in 88 patients were included. Central venous catheters (CVCs) were present in 66 episodes (71.7%) and were the most common infection source (N = 38, 41.3%). The most frequently isolated species was Candida glabrata (40 of 94, 42.6%). IDC was performed in 84 (91.3%) of 92 candidemia episodes. Mortality rates were 20.8% (16 of 77) in the IDC group versus 25% (2 of 8) in the no-IDC group (P = .67). Other comparisons were numerically different but not significant: repeat blood culture (98.8% vs 87.5%; P = .17), echocardiography (70.2% vs 50%; P = .26), CVC removal (91.7% vs 83.3%; P = .45), and initial echinocandin treatment (67.9% vs 50%; P = .44). IDC resulted in more ophthalmology examinations (67.9% vs 12.5%; P = .0035). All patients received antifungal therapy. Antimicrobial stewardship recommendations were performed in 19 episodes (20.7%). The median EQUAL Candida score with CVC was higher with IDC (16 vs 11; P = .001) but not in episodes without CVC (12 vs 11.5; P = .81).
Conclusions:
In the setting of an active antimicrobial stewardship program and high consultation rates, mandatory IDC may not be warranted for candidemia.
This introduction to the mathematics of incompressible fluid mechanics and its applications keeps prerequisites to a minimum – only a background knowledge in multivariable calculus and differential equations is required. Part One covers inviscid fluid mechanics, guiding readers from the very basics of how to represent fluid flows through to the incompressible Euler equations and many real-world applications. Part Two covers viscous fluid mechanics, from the stress/rate of strain relation to deriving the incompressible Navier-Stokes equations, through to Beltrami flows, the Reynolds number, Stokes flows, lubrication theory and boundary layers. Also included is a self-contained guide on the global existence of solutions to the incompressible Navier-Stokes equations. Students can test their understanding on 100 progressively structured exercises and look beyond the scope of the text with carefully selected mini-projects. Based on the authors' extensive teaching experience, this is a valuable resource for undergraduate and graduate students across mathematics, science, and engineering.
Frank H. Berkshire, Imperial College of Science, Technology and Medicine, London,Simon J. A. Malham, Heriot-Watt University, Edinburgh,J. Trevor Stuart, Imperial College of Science, Technology and Medicine, London
Recall our discussion on internal fluid forces in . Here and in the next two sections we consider the explicit form of the shear stresses and in particular the deviatoric stress matrix. This is necessary if we want to consider/model any real fluid, i.e. non-ideal fluid. We explain shear stresses as follows – see , p. 31).
Frank H. Berkshire, Imperial College of Science, Technology and Medicine, London,Simon J. A. Malham, Heriot-Watt University, Edinburgh,J. Trevor Stuart, Imperial College of Science, Technology and Medicine, London
Frank H. Berkshire, Imperial College of Science, Technology and Medicine, London,Simon J. A. Malham, Heriot-Watt University, Edinburgh,J. Trevor Stuart, Imperial College of Science, Technology and Medicine, London
The well-posedness of smooth solutions to the three-dimensional incompressible Navier–Stokes equations globally in time is a major open mathematical problem. Our goal in this chapter is to provide a succinct though comprehensive introduction to the main well-posedness results that are known. In the three-dimensional case, we indicate how smooth solutions may develop singularities in finite time. At the same time we establish classical regularity assumptions/conditions that guarantee well-posedness globally in time, i.e. if we could prove three-dimensional incompressible Navier–Stokes solutions satisfied those assumptions/conditions, then we would establish global regularity.
Frank H. Berkshire, Imperial College of Science, Technology and Medicine, London,Simon J. A. Malham, Heriot-Watt University, Edinburgh,J. Trevor Stuart, Imperial College of Science, Technology and Medicine, London
Frank H. Berkshire, Imperial College of Science, Technology and Medicine, London,Simon J. A. Malham, Heriot-Watt University, Edinburgh,J. Trevor Stuart, Imperial College of Science, Technology and Medicine, London
Frank H. Berkshire, Imperial College of Science, Technology and Medicine, London,Simon J. A. Malham, Heriot-Watt University, Edinburgh,J. Trevor Stuart, Imperial College of Science, Technology and Medicine, London
Herein we focus on two-dimensional irrotational flows which have a rich structure in the sense that they are intimately connected to complex variable theory and analysis.
Frank H. Berkshire, Imperial College of Science, Technology and Medicine, London,Simon J. A. Malham, Heriot-Watt University, Edinburgh,J. Trevor Stuart, Imperial College of Science, Technology and Medicine, London
Frank H. Berkshire, Imperial College of Science, Technology and Medicine, London,Simon J. A. Malham, Heriot-Watt University, Edinburgh,J. Trevor Stuart, Imperial College of Science, Technology and Medicine, London
Let us consider the forces that act on a small parcel of fluid in a fluid flow. There are two types:
1.External or body forces, these may be due to gravity or external electromagnetic fields. They exert a force per unit volume on the continuum.
2.Surface or stress forces, these are forces, molecular in origin, that are applied by the neighbouring fluid across the surface of the fluid parcel.
The surface or stress forces are normal stresses and tangential or shear stresses. In this chapter we only include the stress forces across the fluid parcels due to pressure differentials, representing a specific component of the normal stresses, and we entirely ignore the shear stresses. In other words, we leave out the stress components essentially resulting from molecular diffusion. This is what defines ideal fluid flow.
Frank H. Berkshire, Imperial College of Science, Technology and Medicine, London,Simon J. A. Malham, Heriot-Watt University, Edinburgh,J. Trevor Stuart, Imperial College of Science, Technology and Medicine, London
Frank H. Berkshire, Imperial College of Science, Technology and Medicine, London,Simon J. A. Malham, Heriot-Watt University, Edinburgh,J. Trevor Stuart, Imperial College of Science, Technology and Medicine, London