An Oceanographic Study of the Cavity Beneath the McMurdo Ice Shelf, Antarctica

This thesis reports the first observations of currents, temperature and salinity beneath the McMurdo Ice Shelf, Antarctica. They are reviewed and discussed here in conjunction with results of a numerical modelling study used to simulate current flow and to investigate local sediment deposition. The McMurdo Ice Shelf lies behind Ross Island off the Victoria Land coast of Antarctica, and represents the northwest corner of the much larger Ross Ice Shelf. The site will be drilled by the ANDRILL consortium in 2006, passing through the ice shelf, the water column, and 1000 m into the sea floor, to obtain a record of ice shelf and climate history in this area. This study stems from a site survey carried out in early 2003, for which access holes were melted at two locations on the McMurdo Ice Shelf. Current meters surveyed multiple depths simultaneously during spring tides, and profiles of temperature and salinity were collected through a diurnal tidal cycle at each site. Maximum currents were recorded in the boundary layer at the base of the ice shelf, reaching 0.22 m s−1 during the flood tide. The salinity and temperature profiles were similar at the two sites, with greater temporal variability observed at the site closer to the open water of McMurdo Sound. Supercooling, due to the pressure-dependence of the in-situ freezing temperature, was observed at one of the sites. At the second site, where the draft of the ice shelf was deeper, temperatures corresponding to basal melting were observed. At a third site on the sea ice at the northwestern edge of the McMurdo Ice Shelf, a current meter surveyed the water column to 320 metres below sea level for 23 days. This allowed comparison of current behaviour through spring and neap tides, and between subsea ice and sub-ice shelf environments in the same season. Net throughflow over spring tides at each of the three sites was consistent with transport eastwards from McMurdo Sound along the channel defined by local bathymetry. Profiles of temperature and salinity from beneath the ice shelf were likewise consistent with McMurdo Sound being the source of the observed water masses. Flow along the sub-ice shelf channel was further investigated using an adaptation of a two-dimensional thermohaline ocean model. Year-long profiles of temperature and salinity from southern McMurdo Sound were used to seasonally force the model, resulting in annual variation in all parameters. The rate of melting decreased monotonically from ∼0.6 m yr−1 at the deep end of the ice shelf, into a region of freezing associated with supercooling closer to the McMurdo Sound end of the domain. This change in regime mirrored the observations from the boundary layer beneath the McMurdo Ice Shelf. Sediment transport and deposition were investigated, with settling velocities used to represent sediment sizes ranging from biogenic pellets and fine sand through algal flocs to fine mud, particle types known and described from the present day environment. This method of incorporating sedimentation processes gave results similar to observations from surface sediment cores collected beneath the ice shelf. The larger grains were preferentially deposited close to the open water McMurdo Sound source, whereas fine-grained material was entrained into the general circulation and deposited by regions of down-welling. A settling velocity of ∼1x10−4 m s−1, corresponding to a grain size of ∼5 μm, defined the boundary between these depositional behaviours. Characteristics of the water beneath the ice shelf suggest that it had been transported from McMurdo Sound, being modified through interaction with the base of the ice shelf. This pattern of throughflow was also seen in the current meter data, with a strong tidal signal throughout the water column superimposed on the net transport eastward from McMurdo Sound and under the ice shelf. This net flow pattern was supported by the results of the longer-term simulation experiments

Veterinarian nominated common conditions of rabbits and guinea pigs compared with published literature

Rabbits and guinea pigs are increasingly popular pets in the UK, yet little is known about their common ailments, or how these relate to what appears in the published literature. The aim of this study was to characterise the common conditions of rabbits and guinea pigs, and to compare these with the topics found in the published literature. Information about the common conditions seen in rabbits and guinea pigs in clinical practice was obtained from a survey of UK veterinarians. The common conditions seen were compared with results from a structured literature search. Conditions relating to the dental (29.9%), and skin (37.6%) body systems were commonly nominated by veterinarians for rabbits and guinea pigs, respectively. A total of 655 rabbit and 1086 guinea pig citations were examined and there appeared to be a mismatch between the conditions nominated in the veterinary questionnaire, and those found in the literature. This is the first time that the published literature has been compared to the nominated caseload of veterinarians in practice, and there is concern that the literature about rabbits and guinea pigs may not be representative of, or relevant to the caseload seen in clinical practice. This is of importance for clinicians being able to apply an objective, evidence-based approach. The publishing of clinically-relevant, research-based evidence should be prioritised

Veterinary services during the COVID pandemic: less stressful for cats and their carers?

OBJECTIVES: The COVID-19 pandemic saw major changes to small animal veterinary practice, many of which may have had an impact on stress in cats presented to the clinic. The aim of this study was to examine the nature of feline outpatient visits before and during the pandemic, and examine signs of stress noted in cats before, during and after these visits. METHODS: A questionnaire was used to gather data on cat owner experiences of visits to the veterinary clinic. Data were gathered on the owner’s most recent experience of a consultation, with consultations occurring in February 2020 or earlier coded as a standard consultation, and consultations occurring in March 2020 or later coded as COVID-19 consultations. RESULTS: A total of 371 responses were received, with 210 coded as standard consultations and 161 coded as COVID-19 consultations. Consultation type varied significantly between standard and COVID-19 consultations (P <0.001), with emergency consultations more frequent and preventive healthcare consultations less frequent during the COVID-19 pandemic. The area in which the owner and their cat waited also varied significantly between standard and COVID-19 consultations (P <0.001), with standard consultations more likely to involve time in a waiting room while COVID-19 consultations were often called straight in or waited outside the practice. Most owners notedbehaviours associated with stress in their cats, regardless of consultation type, although trying to hide or escape were noted more frequently for cats seen prior to the COVID-19 pandemic. CONCLUSIONS AND RELEVANCE: The findings suggest that outpatient visits to the veterinary clinic were stressful for cats both prior to and during the COVID-19 pandemic, but some measures taken during the pandemic, for example less use of waiting rooms, could be used alongside existing cat friendly measures to help to reduce stress in feline patients

Next‐generation sequencing in precision oncology: Patient understanding and expectations

BackgroundImplementation of precision oncology interventions poses several challenges to informed consent and patient education. This study assessed cancer patients’ understanding, expectations, and outcomes regarding participation in research examining the impact of matched tumor and germline sequencing on their clinical care.MethodsA total of 297 patients (mean age: 59 years; 50% female; 96% white) with refractory, metastatic cancer were surveyed, including 217 who completed surveys both before and after undergoing integrated whole exome and transcriptome sequencing as part of a larger clinical research study.ResultsAt baseline, the vast majority of patients expected to receive several potential direct benefits from study participation, including written reports of sequencing findings (88%), greater understanding of the causes of their cancer (74%), and participation in clinical trials for which sequencing results would make them eligible (84%). In most cases, these benefits were not realized by study completion. Despite explanations from study personnel to the contrary, most participants (67%‐76%) presumed that incidental germline sequencing findings relevant to noncancerous health conditions (eg, diabetes) would automatically be disclosed to them. Patients reported low levels of concern about study risks at baseline and low levels of regret about study participation at follow‐up.ConclusionsFindings suggest that cancer patients participating in precision oncology intervention research have largely unfulfilled expectations of direct benefits related to their study participation. Increased focus on patient education to supplement the informed consent process may help manage patients’ expectations regarding the extent and likelihood of benefits received as a result of undergoing genomic sequencing.This study assessed cancer patients’ understanding and expectations regarding participation in research examining the impact of matched tumor and germline sequencing on their clinical care. Findings suggest that cancer patients participating in precision oncology intervention research have largely unfulfilled expectations of direct benefits related to their study participation. Increased focus on patient education to supplement the informed consent process may help manage patients’ expectations regarding the extent and likelihood of benefits received as a result of undergoing genomic sequencing.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/147745/1/cam41947.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/147745/2/cam41947_am.pd

Owners and veterinary surgeons in the United Kingdom disagree about what should happen during a small animal vaccination consultation

Dog and cat vaccination consultations are a common part of small animal practice in the United Kingdom. Few data are available describing what happens during those consultations or what participants think about their content. The aim of this novel study was to investigate the attitudes of dog and cat owners and veterinary surgeons towards the content of small animal vaccination consultations. Telephone interviews with veterinary surgeons and pet owners captured rich qualitative data. Thematic analysis was performed to identify key themes. This study reports the theme describing attitudes towards the content of the consultation. Diverse preferences exist for what should be prioritised during vaccination consultations, and mismatched expectations may lead to negative experiences. Vaccination consultations for puppies and kittens were described to have a relatively standardised structure with an educational and preventative healthcare focus. In contrast, adult pet vaccination consultations were described to focus on current physical health problems with only limited discussion of preventative healthcare topics. This first qualitative exploration of UK vaccination consultation expectations suggests that the content and consistency of adult pet vaccination consultations may not meet the needs or expectations of all participants. Redefining preventative healthcare to include all preventable conditions may benefit owners, pets and veterinary surgeons, and may help to provide a clearer structure for adult pet vaccination consultations. This study represents a significant advance our understanding of this consultation type

Owner and veterinary surgeon perspectives on the roles of veterinary nurses and receptionists in relation to small animal preventative healthcare consultations in the United Kingdom

Veterinary receptionists and veterinary nurses rarely feature in published practice-based research, yet are integral to small animal veterinary practice in the United Kingdom (UK). The aim of this study was to investigate the perspectives of UK-based owners and veterinary surgeons about veterinary nurses and receptionists in relation to their role in preventative healthcare. Semi-structured telephone interviews were conducted with 15 dog and cat owners and 14 veterinary surgeons. Interview transcripts were thematically analysed. Reception staff were identified as having a range of important roles, from rapport building to providing healthcare information and advice. The perceived importance of those roles appeared to differ between owners and veterinary surgeons. Veterinary nurses were described as performing a diversity of roles in relation to preventative healthcare, both in the reception area and in the consulting room. Many owners, and some veterinary surgeons, expressed uncertainty about the remit and status of veterinary nurses in relation to providing veterinary advice. This study identifies for the first time the degree of responsibility for preventative healthcare given to veterinary receptionists and veterinary nurses in UK small animal practices. Further work is needed involving reception and nursing staff to fully appreciate and define their roles in small animal practice

Effects of liver-stage clearance by Primaquine on gametocyte carriage of Plasmodium vivax and P. falciparum

Primaquine (PQ) is the only currently licensed antimalarial that prevents Plasmodium vivax (Pv) relapses. It also clears mature P. falciparum (Pf) gametocytes, thereby reducing post-treatment transmission. Randomized PQ treatment in a treatment-to-reinfection cohort in Papua New Guinean children permitted the study of Pv and Pf gametocyte carriage after radical cure and to investigate the contribution of Pv relapses.; Children received radical cure with Chloroquine, Artemether-Lumefantrine plus either PQ or placebo. Blood samples were subsequently collected in 2-to 4-weekly intervals over 8 months. Gametocytes were detected by quantitative reverse transcription-PCR targeting pvs25 and pfs25.; PQ treatment reduced the incidence of Pv gametocytes by 73%, which was comparable to the effect of PQ on incidence of blood-stage infections. 92% of Pv and 79% of Pf gametocyte-positive infections were asymptomatic. Pv and to a lesser extent Pf gametocyte positivity and density were associated with high blood-stage parasite densities. Multivariate analysis revealed that the odds of gametocytes were significantly reduced in mixed-species infections compared to single-species infections for both species (ORPv = 0.39 [95% CI 0.25-0.62], ORPf = 0.33 [95% CI 0.18-0.60], p&lt;0.001). No difference between the PQ and placebo treatment arms was observed in density of Pv gametocytes or in the proportion of Pv infections that carried gametocytes. First infections after blood-stage and placebo treatment, likely caused by a relapsing hypnozoite, were equally likely to carry gametocytes than first infections after PQ treatment, likely caused by an infective mosquito bite.; Pv relapses and new infections are associated with similar levels of gametocytaemia. Relapses thus contribute considerably to the Pv reservoir highlighting the importance of effective anti-hypnozoite treatment for efficient control of Pv.; ClinicalTrials.gov NCT02143934

qRT-PCR versus IFA-based quantification of male and female gametocytes in low-density Plasmodium falciparum infections and their relevance for transmission

Accurate quantification of female and male gametocytes and sex ratios in asymptomatic low-density malaria infections are important for assessing their transmission potential. Gametocytes often escape detection even by molecular methods, therefore ultralow gametocyte densities were quantified in large blood volumes.; Female and male gametocytes were quantified in 161 PCR-positive Plasmodium falciparum infections from a cross-sectional survey in Papua New Guinea. Ten-fold concentrated RNA from 800 µL blood was analyzed using female-specific pfs25 and male-specific pfmget or mssp qRT-PCR. Gametocyte sex ratios from qRT-PCR were compared with those from immunofluorescence assays (IFA).; Gametocytes were identified in 58% (93/161) P. falciparum-positive individuals. Mean gametocyte densities were frequently below 1 female and 1 male gametocyte/µL by qRT-PCR. The mean proportion of males was 0.39 (95% confidence interval, 0.33-0.44) by pfs25/pfmget qRT-PCR; this correlated well with IFA results (Pearsons r2 = 0.91; P < .001). A Poisson model fitted to our data predicted 16% P. falciparum-positive individuals that are likely to transmit, assuming at least 1 female and 1 male gametocyte per 2.5 µL mosquito bloodmeal.; Based on model estimates of female and male gametocytes per 2.5 µL blood, P. falciparum-positive individuals detected exclusively by ultrasensitive diagnostics are negligible for human-to-mosquito transmission.Estimating the transmission potential of ultralow-density malaria infections informs interventions. Almost all infections with ≥1 female and male gametocyte per 2.5 µL mosquito bloodmeal, and thus with highest likelihood of contributing to human-to-mosquito transmission, were detectable by standard molecular diagnostics