Three hypotheses (Cryptic, Female Mimicry, and Winter Adaptation) have been proposed to explain the occurrence of delayed plumage maturation (DPM) in passerine birds. We show that each of these ...hypotheses is really a composite of two different questions about: 1) the proximate function of dull plumage in second year (SY) males and 2) the selective mechanism that has favored that proximate function. We review the three hypotheses in the context of this distinction, and we find little evidence clearly supporting any of them. We propose a new Status Signaling Hypothesis (SSH) suggesting that dull SY male plumage is a reliable signal of subordinance. We suggest that female choice based on male plumage color (as an index of male quality) is the selective mechanism that has favored subordinate status signaling by SY males. If females prefer bright males, then dull plumage may be a reliable signal of subordinance and SY males may experience reduced levels of aggression from adult males. Male characters (like plumage color) are most likely to be the object of female choice when males defend simple nesting territories with little or no variation in territory quality. In such a system, SY males with low resource-holding potential would benefit (via matings or experience) by signaling subordinance and being allowed to settle among more brightly colored adults. Thus, DPM is expected to be more prevalent when males defend simple nesting territories. This prediction of the SSH is supported by data from the literature-a significantly higher proportion of species with DPM defend simple nesting territories (versus all-purpose territories) than do species without DPM.
Full text
Available for:
BFBNIB, FZAB, GIS, IJS, KILJ, NMLJ, NUK, OILJ, PNG, SAZU, SBCE, SBMB, UL, UM, UPUK
The high microbiologic diversity encountered in prosthetic joint infection (PJI) makes the choice of empirical antimicrobial therapies challenging, especially in cases of implant retention or ...one-stage exchange. Despite the risk of dysbiosis and toxicity, the combination of vancomycin with a broad-spectrum β-lactam is currently recommended in all cases, even if Gram-negative bacilli (GNB) might be less represented in late PJI. In this context, this study aimed to describe the microbiologic epidemiology of PJI according to the chronology of infection.
This prospective cohort study (2011–2016) evaluated the microbiologic aetiology of 567 PJI according to time of occurrence from prosthesis implantation—early (<3 months), delayed (3–12 months) and late (>12 months)—as well as mechanism of acquisition.
Initial microbiologic documentation (n = 511; 90.1%) disclosed 164 (28.9%) Staphylococcus aureus (including 26 (16.1%) methicillin-resistant S. aureus), 162 (28.6%) coagulase-negative staphylococci (including 81 (59.1%) methicillin-resistant coagulase-negative staphylococci), 80 (14.1%) Enterobacteriaceae, 74 (13.1%) streptococci and 60 (10.6%) Cutibacterium acnes. Considering nonhaematogenous late PJI (n = 182), Enterobacteriaceae (n = 7; 3.8%) were less represented than in the first year after implantation (n = 56; 17.2%; p <0.001), without difference regarding nonfermenting GNB (4.6% and 2.7%, respectively). The prevalence of anaerobes (n = 40; 21.9%; including 32 (80.0%) C. acnes) was higher in late PJI (p <0.001). Consequently, a broad-spectrum β-lactam might be useful in 12 patients (6.6%) with late PJI only compared to 66 patients (20.3%) with early/delayed PJI (p <0.001).
Considering the minority amount of GNB in late postoperative PJI, the empirical use of a broad-spectrum β-lactam should be reconsidered, especially when a two-stage exchange is planned.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
A technique for estimating the size of objects in photographs is described, and its accuracy and utility are demonstrated using data collected from both captive and free-ranging American coot chicks. ...Measures of the body size and growth rate of chicks are central to many avian studies.
Full text
Available for:
BFBNIB, NMLJ, NUK, PNG, SAZU, UL, UM, UPUK
Background. Legislation requiring the addition of bittering agents to antifreeze enables assessment of the impact on frequency, volume and severity of suicidal antifreeze ingestions. Methods. U.S. ...poison control data were analyzed comparing 130 suicidal antifreeze ingestions occurring in two states after enactment of bittering requirements with 3,493 cases occurring in states (or at times) where bittering was not required. Results. The frequency of suicidal antifreeze ingestions was unchanged after implementation of bittering. The volume implicated, medical outcome distribution, and use of antidotes, hemodialysis, intubation, or critical care, showed no significant difference between bittered and non-bittered groups. Bittering was not a significant contributor (positively or negatively) in predicting lethal or life-threatening medical outcomes. Conclusion. The addition of bittering agents to antifreeze for the purpose of limiting the frequency or severity of suicidal ingestions could not be justified using U.S. poison control data.
Full text
Available for:
DOBA, IJS, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
We compared the ecology of two high arctic finches to determine which ecological factors might influence male parental roles during incubation. Male Snow Buntings (Plectrophenax nivalis) feed their ...mates at the nest throughout the incubation period, while male Lapland Longspurs (Calcarius lapponicus) usually do not. We identified and tested seven ecological factors that could potentially explain the difference between these two species; (1) risk of nest predation, (2) nesting synchrony, (3) potential for polygyny, (4) timing of breeding, (5) diet, (6) distance between nest and foraging areas, and (7) nest microclimate. Of these, only predation rate and nest microclimate differed significantly between longspurs and buntings. Buntings nest in rock cavities and suffer lower overall nest predation than longspurs (28 vs. 51%, respectively), suggesting that this factor could influence the occurrence of incubation feeding. However, since male longspurs could feed their mates away from the nest, risk of nest predation can only explain why incubation feeding at the nest does not occur, not why incubation feeding per se is rare in longspurs. Due to differences in nest microclimate on sunny days, eggs cool more rapidly in bunting nests, suggesting that female longspurs can take advantage of solar radiation to warm their eggs and can consequently spend a higher proportion of their time foraging than female buntings. A comparison of female incubation schedules supports this idea; female longspurs spent more total time off their eggs (X = 25.9 min/h) than female buntings (X = 15.9 min/h). We conclude that, of the factors we investigated, the colder nest microclimate associated withhole nesting has been the most important ecological factor influencing the occurrence and high frequency of incubation feeding in Snow Buntings. We discuss the possibility that hole nesting favors incubation feeding in passerine birds in general.
Full text
Available for:
BFBNIB, INZLJ, NMLJ, NUK, PNG, SAZU, UL, UM, UPUK, ZRSKP
The mechanisms underlying the transition from acute to chronic pain remain unclear. Here, we sought to characterize the transcriptome associated with chronic low back pain as well as the ...transcriptome of the transition from acute to chronic low back pain. For the analysis, we compared the whole blood transcriptome of: (a) patients at the onset of low back pain who no longer had pain within 6 weeks after onset (acute) with patients who developed chronic low back pain at 6 months (chronic T5); and, (b) patients at the onset of low back pain (chronic T1) who developed chronic pain at 6 months with healthy pain-free (normal) controls. The majority of differentially expressed genes were protein coding. We illustrate a unique chronic low back pain transcriptome characterized by significant enrichment for known pain genes, extracellular matrix genes, and genes from the extended major histocompatibility complex (MHC) genomic locus. The transcriptome of the transition from acute to chronic low back pain was characterized by significant upregulation of antigen presentation pathway (MHC class I and II) genes and downregulation of mitochondrial genes associated with oxidative phosphorylation, suggesting a unique genomic signature of vulnerability to low back pain chronicity.
Full text
Available for:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
We made daily visits to 47 Eared Grebe Podiceps nigricollis nests in two colonies to determine the frequency of conspecific brood parasitism. Three criteria were used to detect parasitism: the ...appearance of two or more new eggs in a 24 hour period, new eggs after the host had ceased laying, and the disappearance of a marked egg with the simultaneous appearance of a new unmarked egg. We detected parasitism at 68% of nests in one colony, 14% of nests in the second colony, and 38% of nests in both colonies combined. The spatial dispersion of parasitic eggs among host nests within one colony did not differ from random expectation but, with respect to temporal dispersion, parasites were more likely to lay in host nests in the laying stage than expected by chance. Egg loss was more common at parasitized nests than unparasitized nests, but further studies are needed to confirm whether this is due to egg rejection by hosts. A comparison of clutch sizes in parasitized and unparasitized nests indicated that unparasitized nests never contained more that four eggs - supernormal clutches of five or more eggs thus indicate that parasitism has taken place and, if used as an assay for parasitism, would have identified two thirds of the cases of parasitism in our study. Applying this assay to clutch size information collected 40 years ago at a site close to our study area indicates that parasitism may be a regular feature of Eared Grebe reproduction.
Full text
Available for:
BFBNIB, NMLJ, NUK, PNG, SAZU, UL, UM, UPUK
Explosive magnetotail activity has long been understood in the context of its auroral manifestations. While global models have been used to interpret and understand many magnetospheric processes, the ...temporal and spatial scales of some auroral forms have been inaccessible to global modeling creating a gulf between observational and theoretical studies of these phenomena. We present here an important step toward bridging this gulf using a newly developed global magnetosphere‐ionosphere model with resolution capturing
≲ 30 km azimuthal scales in the auroral zone. In a global magnetohydrodynamic (MHD) simulation of the growth phase of a synthetic substorm, we find the self‐consistent formation and destabilization of localized magnetic field minima in the near‐Earth magnetotail. We demonstrate that this destabilization is due to ballooning‐interchange instability which drives earthward entropy bubbles with embedded magnetic fronts. Finally, we show that these bubbles create localized field‐aligned current structures that manifest in the ionosphere with properties matching observed auroral beads.
Plain Language Summary
The aurora has long been used as a window onto the magnetosphere. However, auroral observations are inherently limited in trying to reconstruct global magnetospheric dynamics from the “magnetic shadow” they cast on Earth. For this reason modeling has been used in tandem with observations to better contextualize and understand the data. Substorms, the violent reconfiguration of the magnetotail and one of the most dynamic magnetospheric phenomena, have been known to be preceded by the formation of bead‐like structures in the aurora. The processes responsible for auroral beading and their causal versus correlative role with substorm onset have remained an enduring mystery. The vast disparity between the spatial scales of auroral beads and those of the global magnetosphere has greatly complicated the use of modeling in unraveling this mystery. We show here for the first time a demonstration of the self‐consistent formation of a magnetospheric configuration that becomes unstable during the period preceding the substorm onset and that this instability manifests in the ionosphere with similar morphology to auroral beads. The global context of the model shows that the magnetospheric processes responsible for beading are not necessarily causal to onset but a consequence of the slow magnetotail reconfiguration that precedes onset.
Key Points
We present the first global magnetosphere simulation to reveal ballooning‐interchange instability of a narrow Bz minimum in the near‐Earth magnetotail
The instability is prominent during the substorm growth phase and generates earthward entropy bubbles with embedded magnetic fronts
The bubbles drive mesoscale ionospheric field‐aligned currents and auroral structures (beads) with properties matching to those observed
Full text
Available for:
FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
Male snow buntings regularly feed their mates on the nest during the incubation period. We removed males from 7 females at the start of incubation (Early Widows) and from 7 others when the eggs ...hatched (Late Widows) to experimentally assess the effects of incubation feeding on the behaviour of females and the reproductive success of both parents. Early Widows spent significantly more time off their nests than Late Widows and Controls. As a consequence, Early Widows had significantly longer incubation periods and a significantly higher proportion of them lost two or more eggs during development. There was no difference between Early and Late Widows in any index of reproductive success measured during the nestling period although significantly earlier brood reduction suggests that Early Widows were in poorer condition than Late Widows. Since both parents benefitted from incubation feeding by increased hatching success and shorter incubation periods, we conclude that this behaviour is an adaptive form of indirect parental care by males and is not the result of female manipulation.
Full text
Available for:
BFBNIB, NMLJ, NUK, PNG, SAZU, UL, UM, UPUK
BK virus (BKV) reactivation has been increasingly associated with the occurrence of late-onset hemorrhagic cystitis (HC) after allogeneic hematopoietic SCT (allo-HSCT) resulting in morbidity and ...sometimes mortality. We investigated the incidence, risk factors and outcome of BKV-HC in 323 consecutive adult patients undergoing allo-HSCT over a 5-year period. BK viremia values for HC staging were evaluated, as well as the medico-economic impact of the complication. Forty-three patients developed BKV-HC. In univariate analysis, young age (P=0.028), unrelated donor (P=0.0178), stem cell source (P=0.0001), HLA mismatching (P=0.0022) and BU in conditioning regimen (P=0.01) were associated with a higher risk of developing BKV-HC. In multivariate analysis, patients receiving cord blood units (CBUs) (P=0.0005) and peripheral blood stem cells (P=0.011) represented high-risk subgroups for developing BKV-HC. BK viremia was directly correlated to HC severity (P=0.011) with a 3 to 6-log peak being likely associated with grades 3 or 4 HC. No correlation was found between BKV-HC and acute graft versus host disease or mortality rate. Patients with BKV-HC required a significantly longer duration of hospitalization (P<0.0001), more RBC (P=0.0003) and platelet transfusions (P<0.0001). Over the 5-year study period, the financial cost of the complication was evaluated at \euro2 376 076 ($3 088 899). Strategies to prevent the occurrence of late-onset BKV-HC after allo-HSCT are urgently needed, especially in CBU and peripheral blood stem cell recipients. BK viremia correlates with the severity of the disease. Prospective studies are required to test prophylactic approaches.
Full text
Available for:
DOBA, EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, IZUM, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UILJ, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
PDF
