162 research outputs found
Factors affecting follower responses to movement calls in cooperatively breeding dwarf mongooses
In social species, individuals maximize the benefits of group living by remaining cohesive and coordinating their actions. Communication is key to collective action, including ensuring that group members move together; individuals often produce signals when attempting to lead a group to a new area. However, the function of these signals, and how responses to them are affected by intrinsic characteristics of the caller and extrinsic factors, has rarely been experimentally tested. We conducted a series of field-based playback experiments with habituated wild dwarf mongooses, Helogale parvula, a cooperatively breeding and territorial species, to investigate follower responses to movement calls. In our first experiment, we found that focal individuals were more likely to respond to playback of ‘movement calls’ than control ‘close calls’, indicating movement calls function as recruitment signals. In a second experiment, we found that focal individuals responded similarly to the movement calls of dominant and subordinate groupmates, suggesting that dominance status (an intrinsic factor) does not influence receiver responses. In a final experiment, we found that individuals responded to the simulated presence of a rival group, but that this outgroup conflict (an extrinsic factor) did not affect responses to movement calls compared to a control situation. This may be because attention is instead focused on the potential presence of an imminent threat. By using playbacks to isolate the acoustic signal from physical movement cues, our results provide experimental evidence of how movement calls help leaders to attract followers and thus adds to our understanding of recruitment signals more generally
CD300lf is the primary physiologic receptor of murine norovirus but not human norovirus
Murine norovirus (MNoV) is an important model of human norovirus (HNoV) and mucosal virus infection more broadly. Viral receptor utilization is a major determinant of cell tropism, host range, and pathogenesis. The bona fide receptor for HNoV is unknown. Recently, we identified CD300lf as a proteinaceous receptor for MNoV. Interestingly, its paralogue CD300ld was also sufficient for MNoV infection in vitro. Here we explored whether CD300lf is the sole physiologic receptor in vivo and whether HNoV can use a CD300 ortholog as an entry receptor. We report that both CD300ld and CD300lf are sufficient for infection by diverse MNoV strains in vitro. We further demonstrate that CD300lf is essential for both oral and parenteral MNoV infection and to elicit anti-MNoV humoral responses in vivo. In mice deficient in STAT1 signaling, CD300lf is required for MNoV-induced lethality. Finally, we demonstrate that human CD300lf (huCD300lf) is not essential for HNoV infection, nor does huCD300lf inhibit binding of HNoV virus-like particles to glycans. Thus, we report huCD300lf is not a receptor for HNoV
Personalised anti-inflammatory therapy for bronchiectasis and cystic fibrosis:selecting patients for controlled trials of neutrophil elastase inhibition
Background
Neutrophil elastase (NE) has been linked to lung neutrophil dysfunction in bronchiectasis and cystic fibrosis (CF), making NE inhibition a potential therapeutic target. NE inhibitor trials have given mixed result perhaps because not all patients have elevated airway NE activity.
Methods
We tested whether a single baseline sputum NE measurement or a combination of clinical parameters could enrich patient populations with elevated NE activity for “personalised medicine”. Intra- and interindividual variations of total and active NE levels in induced sputum from patients with CF or bronchiectasis were monitored over 14 days. Patients with established CF and bronchiectasis (n=5 per group) were recruited. NE was measured using three different methods: one total and two active NE assays. Subsequently, we analysed the association between clinical parameters and NE from a large bronchiectasis cohort study (n=381).
Results
All three assays showed a high degree of day-to-day variability (0–233% over 14 days). There were strong correlations found between all assays (p<0.0001). Despite high day-to-day variability, patients could be stratified into “high” or “low” groups based on moderate cut-off levels. In the bronchiectasis cohort study, factors most associated with high sputum NE levels were: Pseudomonas aeruginosa infection (β-estimate 11.5, 95% CI −6.0–29.0), sputum colour (β-estimate 10.4, 95% CI 4.3–16.6), Medical Research Council dyspnoea score (β-estimate 6.4, 95% CI 1.4–11.4) and exacerbation history (β-estimate 3.4, 95% CI 1.4–5.3). Collectively, P. aeruginosa infection, sputum colour and exacerbation frequency provided the greatest specificity for “high” NE (98.7%, 95% CI 7.0–99.6%).
Conclusion
These results show that patients with bronchiectasis and CF can be effectively divided into “high” or “low” groups, based on sputum NE assays or clinical inclusion criteria
High temperatures in the terrestrial mid-latitudes during the early Palaeogene
The early Paleogene (56–48 Myr) provides valuable information about the Earth’s climate system in an equilibrium high pCO2 world. High ocean temperatures have been reconstructed for this greenhouse period, but land temperature estimates have been cooler than expected. This mismatch between marine and terrestrial temperatures has been difficult to reconcile. Here we present terrestrial temperature estimates from a newly calibrated branched glycerol dialkyl glycerol tetraether-based palaeothermometer in ancient lignites (fossilized peat). Our results suggest early Palaeogene mid-latitude mean annual air temperatures of 23–29 °C (with an uncertainty of ± 4.7 °C), 5–10 °C higher than most previous estimates. The identification of archaeal biomarkers in these same lignites, previously observed only in thermophiles and hyperthermophilic settings, support these high temperature estimates. These mid-latitude terrestrial temperature estimates are consistent with reconstructed ocean temperatures and indicate that the terrestrial realm was much warmer during the early Palaeogene than previously thought
Inhibition of (dppf)nickel-catalysed Suzuki-Miyaura cross-coupling reactions by α-halo-N-heterocycles
A nickel/dppf catalyst system was found to successfully achieve the Suzuki-Miyaura cross-coupling reactions of 3- and 4-chloropyridine and of 6-chloroquinoline but not of 2-chloropyridine or of other α-halo-N-heterocycles. Further investigations revealed that chloropyridines undergo rapid oxidative addition to [Ni(COD)(dppf)] but that α-halo-N-heterocycles lead to the formation of stable dimeric nickel species that are catalytically inactive in Suzuki-Miyaura cross-coupling reactions. However, the corresponding Kumada-Tamao-Corriu reactions all proceed readily, which is attributed to more rapid transmetalation of Grignard reagents
Theorising Global Governance Inside Out: A Response to Professor Ladeur
Professor Ladeur argues that administrative law’s postmodernism (and by extension Global Administrative Law) necessitates that we move beyond relying on ideas of delegation, account- ability and legitimacy. Global Governance, particularly Global Administrative Law and Global Constitutionalism, should try to adapt and experiment with the changing nature of the postmod- ern legality and support the creation of norms that will adapt to the complexities of globalisation. Ladeur’s contestation, similar to GAL’s propositions, can be challenged. By taking the International Criminal Tribunal for Rwanda, a significant contributor to the field of international criminal law, as an example, it is suggested that the creation of networks that Ladeur makes visible may not account for ‘regulatory capture’. This paper will argue that from the outside, the proliferation of networks may suggest that spontaneous accountability is possible. A closer look, however, drawing on anthropological insights from the ICTR, reveals that international institutions are suscepti- ble to capture by special interests. Furthermore, there are two central themes that animate the response to Professor Ladeur: the political nature of international institutions and the history of international law, and the role of institutions in this history
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Zafirlukast is a broad-spectrum thiol isomerase inhibitor that inhibits thrombosis without altering bleeding times
Background and purpose
Multiple members of the thiol isomerase (TI) family of enzymes are present in, and released by platelets. Inhibition of these enzymes results in diminished platelet responses including aggregation, adhesion and thrombus formation. In recent years, the therapeutic potential of TI inhibition has been recognised and drug-development technologies used to identify selective small molecule inhibitors. To date, few pan-TI inhibitors have been characterised and the most studied, bacitracin is known to be nephrotoxic which prohibits its systemic therapeutic usage.
Experimental approach
We therefore sought to identify novel broad-spectrum inhibitors of these enzymes and test their effects in vivo. 3641 compounds were screened for inhibitory effects on the redox activity of ERp5, PDI, ERp57, ERp72 and thioredoxin (TRX) in an insulin turbidity assay. Of the lead compounds identified, zafirlukast (ZFL) was selected for further investigation.
Key results
When applied to platelets, ZFL diminished platelet responses in vitro. ZFL was antithrombotic in murine models of thrombosis but did not impair responses in a model of haemostasis. Since thiol isomerases are known to modulate adhesion receptor function, we explored the effects of ZFL on cell migration. This was inhibited independently of cysteinyl leukotriene receptor expression and was associated with modulation of cell-surface free thiol levels consistent with alterations in redox activity on the cell surface.
Conclusion and implications
We identify zafirlukast to be a novel, potent, broad-spectrum TI inhibitor, with wide ranging effects on platelet function, thrombosis and integrin-mediated cell migration. ZFL is antithrombotic but does not cause bleeding
Association of Accelerometry-Measured Physical Activity and Cardiovascular Events in Mobility-Limited Older Adults: The LIFE (Lifestyle Interventions and Independence for Elders) Study.
BACKGROUND:Data are sparse regarding the value of physical activity (PA) surveillance among older adults-particularly among those with mobility limitations. The objective of this study was to examine longitudinal associations between objectively measured daily PA and the incidence of cardiovascular events among older adults in the LIFE (Lifestyle Interventions and Independence for Elders) study. METHODS AND RESULTS:Cardiovascular events were adjudicated based on medical records review, and cardiovascular risk factors were controlled for in the analysis. Home-based activity data were collected by hip-worn accelerometers at baseline and at 6, 12, and 24 months postrandomization to either a physical activity or health education intervention. LIFE study participants (n=1590; age 78.9±5.2 [SD] years; 67.2% women) at baseline had an 11% lower incidence of experiencing a subsequent cardiovascular event per 500 steps taken per day based on activity data (hazard ratio, 0.89; 95% confidence interval, 0.84-0.96; P=0.001). At baseline, every 30 minutes spent performing activities ≥500 counts per minute (hazard ratio, 0.75; confidence interval, 0.65-0.89 [P=0.001]) were also associated with a lower incidence of cardiovascular events. Throughout follow-up (6, 12, and 24 months), both the number of steps per day (per 500 steps; hazard ratio, 0.90, confidence interval, 0.85-0.96 [P=0.001]) and duration of activity ≥500 counts per minute (per 30 minutes; hazard ratio, 0.76; confidence interval, 0.63-0.90 [P=0.002]) were significantly associated with lower cardiovascular event rates. CONCLUSIONS:Objective measurements of physical activity via accelerometry were associated with cardiovascular events among older adults with limited mobility (summary score >10 on the Short Physical Performance Battery) both using baseline and longitudinal data. CLINICAL TRIAL REGISTRATION:URL: http://www.clinicaltrials.gov. Unique identifier: NCT01072500
Competition and habitat quality influence age and sex distribution in wintering rusty blackbirds.
Bird habitat quality is often inferred from species abundance measures during the breeding and non-breeding season and used for conservation management decisions. However, during the non-breeding season age and sex classes often occupy different habitats which suggest a need for more habitat-specific data. Rusty Blackbird (Euphagus carolinus) is a forested wetland specialist wintering in bottomland hardwood forests in the south-eastern U. S. and belongs to the most steeply declining songbirds in the U.S. Little information is available to support priority birds such as the Rusty Blackbird wintering in this threatened habitat. We assessed age and sex distribution and body condition of Rusty Blackbirds among the three major habitats used by this species in the Lower Mississippi Alluvial Valley and also measured food availability. Overall, pecan groves had the highest biomass mainly driven by the amount of nuts. Invertebrate biomass was highest in forests but contributed only a small percentage to overall biomass. Age and sex classes were unevenly distributed among habitats with adult males primarily occupying pecan groves containing the highest nut biomass, females being found in forests which had the lowest nut biomass and young males primarily staying in forest fragments along creeks which had intermediate nut biomass. Males were in better body condition than females and were in slightly better condition in pecan groves. The results suggest that adult males occupy the highest quality habitat and may competitively exclude the other age and sex classes
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