Data paucity can seem to hinder science‐based approaches to the conservation of imperiled species. Yet, even individually limited datasets can improve understanding and management of complex ...ecological systems when carefully integrated. We demonstrate this approach to gain first insights on the transmission ecology of Yersinia pestis in Grasslands National Park (GNP), Canada, where both the bacterium and its rodent host, the nationally threatened black‐tailed prairie dog (BTPD, Cynomys ludovicianus), reach the northern limit of their distribution in North America. Primarily flea‐borne, Y. pestis causes sylvatic plague, a disease of exceptional relevance to both human health and wildlife conservation. We integrated data collected independently by multiple organizations in 2010–2017 across 17 BTPD colonies, where the species co‐occur with Richardson's ground squirrels (RGS, Urocitellus richardsonii). Available data included estimates of BTPD density and occupancy from visual counts and colony mapping; information on flea distribution, abundance, and prevalence of infection with Y. pestis from burrow swabbing, animal combing, and PCR assays; and the response of these variables to deltamethrin application on BTPD colony sections. Our analyses suggest that sylvatic plague in GNP is maintained at an enzootic level (i.e., chronic presence affecting a low proportion of individuals) with no evidence of widespread mortality, at least partially due to reduced flea activity after spring (percentage of prevalence in burrows: April–May = 11.69–33.89%; June–September: 1.75–3.19%), low prevalence of Y. pestis in flea samples (95% CI = 0.42–2.27%), and relatively low BTPD densities. Nonetheless, reducing flea prevalence through insecticide application had a positive effect on BTPD abundance, suggesting that enzootic plague is causing chronic mortality. Because flea prevalence on hosts was higher following drier years and higher on RGS than on BTPD (26.69% vs. 3.27%), insecticide application may be particularly important during dry periods and may need to take RGS and their movements into consideration. Differences between flea communities sampled by burrow swabbing and host combing suggest that plague surveillance should integrate both methods. Effects of projected climate change on vector life cycles, flea community composition, and host–parasite interactions warrant continued monitoring and an adaptive approach to species recovery actions and plague mitigation measures.
Despite evidence supporting its use, nasogastric rehydration is rarely used in North America. We conducted a prospective, cross-sectional, 3-phase study to evaluate current perspectives.
We compared ...the proportions of respondents in favor of nasogastric (as opposed to intravenous) rehydration, should oral rehydration fail, between clinicians and caregivers. Phase 1: caregivers of children aged 3 to 48 months, who presented to a Canadian pediatric emergency department with symptoms of gastroenteritis, were invited to complete a survey. Phase 2: phase 1 participants administered intravenous or nasogastric rehydration had the procedure observed and outcome data recorded. Phase 3: pediatric emergency medicine physicians, fellows, and nurses completed a survey.
Four hundred thirty-five children-parent dyads and 113 health care providers participated. If oral rehydration were to fail, 10% (47 of 435) of caregivers and 14% (16 of 113) of clinicians would choose nasogastric rehydration (difference = 3.4%; 95% confidence interval: -2.8 to 11.4). Caregivers were more familiar with the term intravenous than nasogastric rehydration (80% vs 20%; P < .001). Sixty-four children (15%) received intravenous rehydration; none received nasogastric rehydration. Participating nurses have inserted 90 (interquartile range: 25-150) intravenous cannulas compared with 4 (interquartile range: 2-10) nasogastric tubes during the preceding 6 months (P < .001). After a brief educational intervention, the proportion recommending nasogastric rehydration increased to 27% (117 of 435) among caregivers (P < .001) and 43% (49 of 113) among health care providers (P < .001).
In keeping with caregiver desires, health care providers in a Canadian emergency department employ intravenous rehydration when oral rehydration fails. Enhanced change management strategies will be required for nasogastric rehydration to become adopted in this environment.
Despite growing knowledge, neonatal pain remains unrecognized, undertreated, and generally challenging. A cross-sectional survey study was conducted to investigate neonatal nurses’ perceptions, ...knowledge, and practice of infant pain in the United States and China, including 343 neonatal nurses (American nurses n = 237; Chinese nurses n = 106). Nurses’ responses regarding neonatal pain reflected adequate knowledge in general pain concepts, but knowledge deficits related to several topics were found (e.g., preterm infants are more sensitive to pain and long-term consequences of pain). Most reported regular use of pain assessment tools, but fewer agreed that the tool used was appropriate and accurate. More American nurses (83%) than Chinese nurses (58%) felt confident in the use of pain medications, while more Chinese nurses (78%) than American nurses (61%) acknowledged the effectiveness of nonpharmacologic interventions. About half reported that pain in their units was well managed (American: 44.3%; Chinese: 55.7%), and less than half felt that pain guidelines/protocols were research-based (American: 42.6%; Chinese: 34.9%). Nurses’ perceptions of well-managed pain in their units were significantly correlated with adequate education/training, use of accurate tools, and use of research-based protocols. Barriers to effective pain management included resistance to change, lack of knowledge, lack of time, fear of side effects of pain medication, and lack of trust in the tools. The survey reflects concerns that pain has not been well managed in many neonatal intensive care units in the United States and China. Further actions are needed to solve the issues of inadequate training, lack of clinically feasible pain tools, and absence of evidence-based guidelines/protocols.
Abstract We present a new upper limit on the cosmic molecular gas density at z = 2.4–3.4 obtained using the first year of observations from the CO Mapping Array Project (COMAP). COMAP data cubes are ...stacked on the 3D positions of 243 quasars selected from the Extended Baryon Oscillation Spectroscopic Survey (eBOSS) catalog, yielding a 95% upper limit for flux from CO(1–0) line emission of 0.129 Jy km s −1 . Depending on the balance of the emission between the quasar host and its environment, this value can be interpreted as an average CO line luminosity L CO ′ of eBOSS quasars of ≤1.26 × 10 11 K km pc 2 s −1 , or an average molecular gas density ρ H 2 in regions of the Universe containing a quasar of ≤1.52 × 10 8 M ⊙ cMpc −3 . The L CO ′ upper limit falls among CO line luminosities obtained from individually targeted quasars in the COMAP redshift range, and the ρ H 2 value is comparable to upper limits obtained from other line intensity mapping (LIM) surveys and their joint analyses. Further, we forecast the values obtainable with the COMAP/eBOSS stack after the full 5 yr COMAP Pathfinder survey. We predict that a detection is probable with this method, depending on the CO properties of the quasar sample. Based on the achieved sensitivity, we believe that this technique of stacking LIM data on the positions of traditional galaxy or quasar catalogs is extremely promising, both as a technique for investigating large galaxy catalogs efficiently at high redshift and as a technique for bolstering the sensitivity of LIM experiments, even with a fraction of their total expected survey data.
BackgroundIndividuals with mood disorders often report lingering health-related quality of life (HRQOL) and social and cognitive impairments even after mood symptoms have improved. Exercise ...programmes improve mood symptoms in patients, but whether exercise improves functional outcomes in patients with difficult-to-treat mood disorders remains unknown.DesignWe evaluated the impact of a 12-week structured running programme on cognitive, social and quality-of-life outcomes in participants with difficult-to-treat mood disorders.MethodsIn a prospective, open-label study, patients referred to the St Joseph’s Healthcare Hamilton Team Unbreakable running programme for youth and adults with mood disorders completed a comprehensive assessment battery before and after the 12-week exercise intervention.ResultsWe collected preintervention and postintervention data from 18 participants who improved on the general health, vitality, role of emotions, social functioning and mental health (all p≤0.01) HRQOL subscales. Performance improved on cognitive tests that assessed working memory and processing speed (p≤0.04); there were no improvements in complex executive functioning tasks. Regression analyses indicated that younger age, shorter illness duration and reduced bodily pain predicted social and cognitive outcomes.ConclusionParticipation in a group-based, structured running programme was associated with improved HRQOL and social and cognitive function.
ObjectiveAlthough numerous studies suggest a salutary effect of exercise on mood, few studies have explored the effect of exercise in patients with complex mental illness. Accordingly, we evaluated ...the impact of running on stress, anxiety and depression in youth and adults with complex mood disorders including comorbid diagnoses, cognitive and social impairment and high relapse rates.MethodsParticipants were members of a running group at St Joseph Healthcare Hamilton’s Mood Disorders Program, designed for clients with complex mood disorders. On a weekly basis, participants completed Cohen’s Perceived Stress Scale, Beck Depression Inventory (BDI) and Beck Anxiety Inventory (BAI) questionnaires, providing an opportunity to evaluate the effect of running in this population.ResultsData collected for 46 participants from April 2012 to July 2015 indicated a significant decrease in depression (p<0.0001), anxiety (p<0.0001) and stress (p=0.01) scores. Whereas younger participant age, younger age at onset of illness and higher perceived levels of friendship with other running group members (ps≤0.04) were associated with lower end-of-study depression, anxiety and stress scores, higher attendance was associated with decreasing BDI and BAI (ps≤0.01) scores over time. ConclusionsAerobic exercise in a supportive group setting may improve mood symptoms in youth and adults with complex mood disorders, and perceived social support may be an important factor in programme’s success. Further research is required to identify specifically the mechanisms underlying the therapeutic benefits associated with exercise-based therapy programmes.
Low-ionization metal absorption due to O i has been identified as an important probe of the physical state of the intergalactic/circumgalactic medium at the tail end of reionization. We use here ...high-resolution hydrodynamic simulations to interpret the incidence rate of O i absorbers at z ∼ 6 as observed by Becker et al. We infer weak O i absorbers (EW ≳ 0.1 Å) to have typical H i column densities in the range of sub-damped Lyman α systems, densities of 80 times the mean baryonic density and metallicities of about 1/500th solar. This is similar to the metallicity inferred at similar overdensities at z ∼ 3, suggesting that the metal enrichment of the circumgalactic medium around low-mass galaxies has already progressed considerably by z ∼ 6. The apparently rapid evolution of the incidence rates for O i absorption over the redshift range 5 ≲ z ≲ 6 mirrors that of self-shielded Lyman-limit systems at lower redshift and is mainly due to the rapid decrease of the metagalactic photoionization rate at z ≳ 5. We predict the incidence rate of O i absorbers to continue to rise rapidly with increasing redshift as the IGM becomes more neutral. If the distribution of metals extends to lower density regions, O i absorbers will allow the metal enrichment of the increasingly neutral filamentary structures of the cosmic web to be probed.
Abstract Measurements of the mean free path of Lyman-continuum photons in the intergalactic medium during the epoch of reionization can help constrain the nature of the sources as well as sinks of ...hydrogen-ionizing radiation. A recent approach to this measurement has been to utilize composite spectra of multiple quasars at z ∼ 6, and infer the mean free path after correcting the spectra for the presence of quasar proximity zones. This has revealed not only a steep drop in the mean free path from z = 5 to z = 6, but also potentially a mild tension with reionization simulations. We critically examine such direct measurements of the mean free path for biases due to quasar environment, incomplete reionization, and quasar proximity zones. Using cosmological radiative transfer simulations of reionization combined with one-dimensional radiative transfer calculations of quasar proximity zones, we find that the bias in the mean free path due to overdensities around quasars is minimal at z ∼ 6. Patchiness of reionization at this redshift also does not affect the measurements significantly. Fitting our model to the data results in a mean free path of $\lambda _{\mathrm{mfp}}=1.49^{+0.47}_{-0.52}$ pMpc at z = 6, which is consistent with the recent measurements in the literature, indicating robustness with respect to the modelling of quasar proximity zones. We also compare various ways in which the mean free path has been defined in simulations before the end of reionization. Overall, our finding is that recent measurements of the mean free path appear to be robust relative to several sources of potential bias.
Reionization in Technicolor Finlator, Kristian; Keating, Laura; Oppenheimer, Benjamin D ...
Monthly Notices of the Royal Astronomical Society,
10/2018, Letnik:
480, Številka:
2
Journal Article
Recenzirano
Odprti dostop
We present the Technicolor Dawn simulations, a suite of cosmological radiation hydrodynamic simulations of the first 1.2 billion yr. By modelling a spatially inhomogeneous ultraviolet background ...(UVB) on the fly with 24 frequencies and resolving dark matter haloes down to 10(8) M-circle dot within 12 h(-1) Mpc volumes, our simulations unify observations of the intergalactic and circumgalactic media, galaxies, and reionization into a common framework. The only empirically tuned parameter, the fraction f(esc,gal)(z) of ionizing photons that escape the interstellar medium, is adjusted to match observations of the Lyman-alpha forest and the cosmic microwave background. With this single calibration, our simulations reproduce the history of reionization; the stellar mass and star formation rate relation of galaxies; the number density and metallicity of damped Lyman-alpha absorbers (DLAs) at z similar to 5; the abundance of weak metal absorbers; the ultraviolet background amplitude; and the Lyman-a flux power spectrum at z = 5.4. The galaxy stellar mass and ultraviolet luminosity functions are underproduced by <= 2 x, suggesting an overly vigorous feedback model. The mean transmission in the Lyman-alpha forest is underproduced at z < 6, indicating tension between measurements of the UVB amplitude and Lyman-alpha transmission. The observed Si IV column density distribution is reasonably well reproduced (similar to 1 sigma low). By contrast, C IV remains significantly underproduced despite being boosted by an intense >4 Ryd UVB. Solving this problem by increasing metal yields would overproduce both weak absorbers and DLA metallicities. Instead, the observed strength of high-ionization emission from high-redshift galaxies and absorption from their environments suggest that the ionizing flux from conventional stellar population models is too soft.
PDF
![A [C ii] 158 μm emitter ass...](http://api.summon.serialssolutions.com/2.0.0/image/issn/XR4PS5YY4K/2397-3366/small "A [C ii] 158 μm emitter associated with an O i absorber at the end of the reionization epoch")
