Population-level estimates of species' distributions can reveal fundamental ecological processes and facilitate conservation. However, these may be difficult to obtain for mobile species, especially ...colonial central-place foragers (CCPFs; e.g., bats, corvids, social insects), because it is often impractical to determine the provenance of individuals observed beyond breeding sites. Moreover, some CCPFs, especially in the marine realm (e.g., pinnipeds, turtles, and seabirds) are difficult to observe because they range tens to ten thousands of kilometers from their colonies. It is hypothesized that the distribution of CCPFs depends largely on habitat availability and intraspecific competition. Modeling these effects may therefore allow distributions to be estimated from samples of individual spatial usage. Such data can be obtained for an increasing number of species using tracking technology. However, techniques for estimating population-level distributions using the telemetry data are poorly developed. This is of concern because many marine CCPFs, such as seabirds, are threatened by anthropogenic activities. Here, we aim to estimate the distribution at sea of four seabird species, foraging from approximately 5,500 breeding sites in Britain and Ireland. To do so, we GPS-tracked a sample of 230 European Shags Phalacrocorax aristotelis, 464 Black-legged Kittiwakes Rissa tridactyla, 178 Common Murres Uria aalge, and 281 Razorbills Alca torda from 13, 20, 12, and 14 colonies, respectively. Using Poisson point process habitat use models, we show that distribution at sea is dependent on (1) density-dependent competition among sympatric conspecifics (all species) and parapatric conspecifics (Kittiwakes and Murres); (2) habitat accessibility and coastal geometry, such that birds travel further from colonies with limited access to the sea; and (3) regional habitat availability. Using these models, we predict space use by birds from unobserved colonies and thereby map the distribution at sea of each species at both the colony and regional level. Space use by all four species' British breeding populations is concentrated in the coastal waters of Scotland, highlighting the need for robust conservation measures in this area. The techniques we present are applicable to any CCPF.
To evaluate the effects of BRAF inhibition on the tumor microenvironment in patients with metastatic melanoma.
Thirty-five biopsies were collected from 16 patients with metastatic melanoma ...pretreatment (day 0) and at 10 to 14 days after initiation of treatment with either BRAF inhibitor alone (vemurafenib) or BRAF + MEK inhibition (dabrafenib + trametinib) and were also taken at time of progression. Biopsies were analyzed for melanoma antigens, T-cell markers, and immunomodulatory cytokines.
Treatment with either BRAF inhibitor alone or BRAF + MEK inhibitor was associated with an increased expression of melanoma antigens and an increase in CD8+ T-cell infiltrate. This was also associated with a decrease in immunosuppressive cytokines interleukin (IL)-6 and IL-8 and an increase in markers of T-cell cytotoxicity. Interestingly, expression of exhaustion markers TIM-3 and PD1 and the immunosuppressive ligand PDL1 was increased on treatment. A decrease in melanoma antigen expression and CD8 T-cell infiltrate was noted at time of progression on BRAF inhibitor alone and was reversed with combined BRAF and MEK inhibition.
Together, these data suggest that treatment with BRAF inhibition enhances melanoma antigen expression and facilitates T-cell cytotoxicity and a more favorable tumor microenvironment, providing support for potential synergy of BRAF-targeted therapy and immunotherapy. Interestingly, markers of T-cell exhaustion and the immunosuppressive ligand PDL1 are also increased with BRAF inhibition, further implying that immune checkpoint blockade may be critical in augmenting responses to BRAF-targeted therapy in patients with melanoma.
Knowledge of seabird distributions plays a key role in seabird conservation and sustainable marine management, underpinning efforts to designate protected areas or assess the impact of human ...developments. Technological advances in animal tracking devices increasingly allow researchers to acquire information on the movement of birds from specific colonies. Nevertheless, most seabird colonies have not been subject to such tracking and another means must be found to assess their likely foraging distribution. Consequently, foraging range data collated and summarized across other tracking studies has often been used to estimate species‐level foraging distances for use within applied settings. However, generic species‐specific foraging ranges must be used with caution because of the amount of variation in seabird foraging behaviour at both the individual and colony levels. Specifically, although current reviews of seabird foraging ranges provide summary estimates of maximum foraging range, they typically do not assess the extent of among‐colony or among‐individual variation around such estimates. To address this, we conducted a variance component analysis of the maximum distance reached from the breeding colony per foraging trip (foraging range) using multi‐colony tracking datasets to estimate the degree of between‐individual, between‐year and between‐colony variation in foraging range in four UK breeding seabirds (Black‐legged Kittiwake Rissa tridactyla, Common Guillemot Uria aalge, Razorbill Alca torda and European Shag Gulosus aristotelis). We also provide updated estimates of typical foraging ranges for each species and quantify the influence of breeding stage and colony size. Overall, between‐colony variation was typically the largest variance component, explaining 20–30% of the observed variation in foraging range across the four species. Individual‐level variation was also relatively large among Shag. In Kittiwake, Guillemot and Shag, but not Razorbill, average foraging ranges were positively associated with colony size. In addition, Kittiwake and Razorbill travelled further during incubation than during chick‐rearing. More generally, our estimates of mean foraging ranges for each species were subject to a high degree of uncertainty, which should be incorporated into impact assessments carried out using such data.
The provision of artificial nest structures is used in the conservation of a broad range of bird groups including raptors, owls, ducks, passerines and seabirds, with varying degrees of success.
...Artificial nestboxes have been provided to increase the density and breeding success of Roseate Tern pairs at colonies in north‐west Europe and the eastern seaboard of the USA and Canada, but their effect on breeding productivity has never been comprehensively quantified.
Using 15 years of monitoring data, based on daily nest monitoring visits, we carried out a comparative analysis of the breeding performance of Roseate Tern pairs utilizing artificial nestboxes with those in open nests, on Rockabill Island (Ireland), to evaluate the effectiveness of nestbox installation as a conservation measure.
Nestboxes were used ahead of open sites early in the season, likely by the experienced breeding pairs. Hatching success and fledging success were higher for pairs in nestboxes compared with those in open nest sites. Earlier clutches were more successful than later ones, independent of the effects of nest site type.
The results of this study show definitively that Roseate Terns nesting in nestboxes perform better than those using open nest sites at their largest European colony and that nestboxes are chosen ahead of other sites, likely by the experienced breeding pairs. We recommend the continued and expanded use of nestboxes to help maximize the densities and breeding performance of the Roseate Tern.
A Roseate Tern using a nestbox on Rockabill Island. We show, using comparative analyses of long‐term breeding data, that nests in nestboxes are more productive than open nests. More eggs successfully survive to hatch and more nestlings survive to fledge in nestboxes.
Seabirds are central place foragers during the breeding season and, as marine food resources are often patchily distributed, flexibility in foraging behaviour may be important in maintaining prey ...delivery rates to chicks. We developed a methodological approach using a combination of GPS data loggers and temperature-depth recorders that allowed us to describe the behaviour of surface-feeding seabirds. Specifically, we tested whether differences in foraging behaviour of black-legged kittiwakesRissa tridactylacould be linked with reproductive success by comparing 2 consecutive years at 2 sites. At Rathlin Island (Northern Ireland) during 2010, foraging differed markedly from that during 2009 and from that at Lambay Island (Republic of Ireland) during both years. Birds exhibited foraging trips of greater duration, travelled a greater total distance, spent more time in transit and spent longer recuperating on the surface of the water. This notable shift was associated with a decline in breeding success, with greater loss of eggs to predation and lower prey delivery rates, resulting in the starvation of 15% of chicks. We suggest that food resources were reduced or geographically less accessible during 2010, with suitable foraging areas located further from the colony. Birds did not invest greater amounts of time attempting to catch prey. Thus, our results indicate that kittiwakes at Rathlin modulated their foraging behaviour not by increasing foraging effort through feeding more intensively within prey patches but by extending their range to increase the probability of encountering more profitable prey patches.
A number of mammalian antimicrobial proteins produced by neutrophils and cells of epithelial origin have chemotactic and activating effects on host cells, including cells of the immune system. ...Eosinophil granules contain an antimicrobial protein known as eosinophil-derived neurotoxin (EDN), which belongs to the RNase A superfamily. EDN has antiviral and chemotactic activities in vitro. In this study, we show that EDN, and to a lesser extent human pancreatic RNase (hPR), another RNase A superfamily member, activates human dendritic cells (DCs), leading to the production of a variety of inflammatory cytokines, chemokines, growth factors, and soluble receptors. Human angiogenin, a RNase evolutionarily more distant to EDN and hPR, did not display such activating effects. Additionally, EDN and hPR also induced phenotypic and functional maturation DCs. These RNases were as efficacious as TNF-alpha, but induced a different set of cytokine mediators. Furthermore, EDN production by human macrophages could be induced by proinflammatory stimuli. The results reveal the DC-activating activity of EDN and hPR and suggest that they are likely participants of inflammatory and immune responses. A number of endogenous mediators in addition to EDN have been reported to have both chemotactic and activating effects on APCs, and can thus amplify innate and Ag-specific immune responses to danger signals. We therefore propose these mediators be considered as endogenous multifunctional immune alarmins.
•Maximum entropy modelling was used to identify kittiwake feeding habitats.•Extent of optimal habitat and reproductive success declined between years.•MPA designation may be less effective where ...variability in feeding habitat is high.•Complementary approaches to the current proposed MPA networks are advocated.
Marine Protected Areas (MPAs) are an important conservation tool. For marine predators, recent research has focused on the use of Species Distribution Models (SDMs) to identify proposed sites. We used a maximum entropy modelling approach based on static and dynamic oceanographic parameters to determine optimal feeding habitat for black-legged kittiwakes (Rissa tridactyla) at two colonies during two consecutive breeding seasons (2009 and 2010). A combination of Geographic Positioning System (GPS) loggers and Time-Depth Recorders (TDRs) attributed feeding activity to specific locations. Feeding areas were<30km from the colony, <40km from land, in productive waters, 25–175m deep. The predicted extent of optimal habitat declined at both colonies between 2009 and 2010 coincident with declines in reproductive success. Whilst the area of predicted optimal habitat changed, its location was spatially stable between years. There was a close match between observed feeding locations and habitat predicted as optimal at one colony (Lambay Island, Republic of Ireland), but a notable mismatch at the other (Rathlin Island, Northern Ireland). Designation of an MPA at Rathlin may, therefore, be less effective than a similar designation at Lambay perhaps due to the inherent variability in currents and sea state in the North Channel compared to the comparatively stable conditions in the central Irish Sea. Current strategies for designating MPAs do not accommodate likely future redistribution of resources due to climate change. We advocate the development of new approaches including dynamic MPAs that track changes in optimal habitat and non-colony specific ecosystem management.
This study examined HIV superinfection in HIV-infected women postpartum, and its association with mother-to-child transmission (MTCT).
Plasma samples were obtained from HIV-infected women who ...transmitted HIV to their infants after 6 weeks of age (transmitters, n = 91) and HIV-infected women who did not transmit HIV to their infants (nontransmitters, n = 91). These women were originally enrolled in a randomized trial for prevention of MTCT of HIV in Malawi (Post-Exposure Prophylaxis of Infants trial in Malawi).
Two HIV genomic regions (p24 and gp41) were analyzed by next-generation sequencing for HIV superinfection. HIV superinfection was established if the follow-up sample contained a new, phylogenetically distinct viral population. HIV superinfection and transmission risk were examined by multiple logistic regression, adjusted for Post-Exposure Prophylaxis of Infants study arm, baseline viral load, baseline CD4 cell count, time to resumption of sex, and breastfeeding duration.
Transmitters had lower baseline CD4 cell counts (P = 0.001) and higher viral loads (P < 0.0001) compared with nontransmitters. There were five cases of superinfection among transmitters (rate of superinfection = 4.7/100 person-years) compared with five cases among the nontransmitters (rate of superinfection = 4.4/100 person-years; P = 0.78). HIV superinfection was not associated with increased risk of postnatal MTCT of HIV after controlling for maternal age, baseline viral load, and CD4 cell count (adjusted odds ratio = 2.32, P = 0.30). Longer breastfeeding duration was independently associated with a lower risk of HIV superinfection after controlling for study arm and baseline viral load (P = 0.05).
There was a significant level of HIV superinfection in women postpartum, but this was not associated with an increased risk of MTCT via breastfeeding.
Estimation of Electron Transfer Distances from AM1 Calculations Nelsen, Stephen F; Newton, Marshall D
The journal of physical chemistry. A, Molecules, spectroscopy, kinetics, environment, & general theory,
11/2000, Letnik:
104, Številka:
44
Journal Article
Recenzirano
We examine a simple approximate method for calculating the electron transfer (ET) distance suitable for extracting the off-diagonal electronic coupling element (H ab ) of Marcus−Hush theory from the ...optical spectrum of nitrogen-centered organic intervalence radical cations. A very simple estimate of the ET distance on the adiabatic ground-state surface (d 12(dm)) is employed. AM1-UHF calculation of the dipole moment component in the long axis direction (μ1) for the radical cation using the center of mass as the origin gives the estimated d 12(dm) (Å) = 2μ1(Debye)/4.8023 (eq 7). Cave and Newton's Generalized Mulliken−Hush theory equation allows calculation of the diabatic counterpart (d ab ) in terms of d 12 and the transition dipole moment (μ12), obtained from the experimental intervalence optical band. These calculations indicate that d ab is significantly smaller than the distance between the nominal sites or charge localization, ratio 0.82−0.85 for the aromatic-bridged bis(hydrazines), 0.76−0.87 for the unsaturated-bridged bis(triarylamines), 0.74−0.79 for the saturated-bridged bis(diazenes), and 0.71−0.85 for the saturated-bridged bis(hydrazines) examined here. Furthermore, d ab is not very different for diastereomers that differ in relative orientation of the oxidized and reduced charge-bearing units for the aromatic-bridged compounds; experimental data corresponds to a superposition of the spectra of such isomers. There appears to be a problem with the trend of calculated ET distances as methyl groups are substituted on a benzene-1,4-diyl bridge. The d 12(dm) calculated is smaller for the compound with the tetramethyl-substituted bridge (DU) than that with the dimethyl-substituted bridge (XY), in contrast to the general trend in d 12 as twisting increases, and to the dipolar splitting constant for the triplet form of the dication oxidation states of these compounds.
Capsule We examined regurgitates from Black-legged Kittiwakes during the early chick-rearing period over two breeding seasons at two colonies in Ireland where diet has not been studied previously. ...Clupeids were the dominant food source at both colonies, which contrasts with other studies throughout the British Isles that suggest Kittiwakes feed mainly on sandeels during this period. Our study is limited by sample size and restricted to the early breeding season, but suggests a link between reproductive success and dietary composition which should be investigated further.
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