Seasonal Lekking Behavior of the Greater Prairie-Chicken in Illinois

Spring behavior of prairie-chickens (Tympanuchus cupido) has been studied extensively, however there is little information on fall-winter lekking activity. Greater prairie-chickens were observed weekly on a lek from 25 September 1982 to 23 June 1983 during morning and evening hours in Jasper County, Illinois. The peak number of prairie-chicken males on the lek occurred in February although hen attendance did not occur until 10 March 1983. All spring lekking activities were higher compared to that of the fall-winter period. Fall-winter lek activity was aggression which centered on probably brief, less intense male aggression which probably establishes or maintains territorial boundaries. Imperfect booming performances were common during the fall-winter with each display being best developed and most intense during hen attendance. The AM period was less variable in daily attendance; significantly higher in time spent on the lek, Activity Index (i.e. Indice which incorporates time spent on the lek, mean encounters per cock, number of males involved in aggression and attendance on the lek; used to evaluate male behavior) and numbers of males on the lek; compared to that of the PM. The PM period was more affected by cloud cover (51-100%) and was associated with significantly less time spent on the lek, earlier departure times and a lower Activity Index. The northern harrier (Circus cyaneus) accounted for 97.3% of the interspecific interactions with repeated harassment being the most common behavior observed. Ring-necked pheasant (Phasianus colchicus) interactions were observed, however they appeared to be of little effect on lekking behavior in this study

Regional disparities and seasonal differences in climate risk to rice labour.

The 880 million agricultural workers of the world are especially vulnerable to increasing heat stress due to climate change, affecting the health of individuals and reducing labour productivity. In this study, we focus on rice harvests across Asia and estimate the future impact on labour productivity by considering changes in climate at the time of the annual harvest. During these specific times of the year, heat stress is often high compared to the rest of the year. Examining climate simulations of the Coupled Model Intercomparison Project 6 (CMIP6), we identified that labour productivity metrics for the rice harvest, based on local wet-bulb globe temperature, are strongly correlated with global mean near-surface air temperature in the long term (p ≪ 0.01, R 2 > 0.98 in all models). Limiting global warming to 1.5 °C rather than 2.0 °C prevents a clear reduction in labour capacity of 1% across all Asia and 2% across Southeast Asia, affecting the livelihoods of around 100 million people. Due to differences in mechanization between and within countries, we find that rice labour is especially vulnerable in Indonesia, the Philippines, Bangladesh, and the Indian states of West Bengal and Kerala. Our results highlight the regional disparities and importance in considering seasonal differences in the estimation of the effect of climate change on labour productivity and occupational heat-stress

Degenerate dispersive equations arising in the study of magma dynamics

An outstanding problem in Earth science is understanding the method of transport of magma in the Earth's mantle. Models for this process, transport in a viscously deformable porous media, give rise to scalar degenerate, dispersive, nonlinear wave equations. We establish a general local well-posedness for a physical class of data (roughly $H^1$) via fixed point methods. The strategy requires positive lower bounds on the solution. This is extended to global existence for a subset of possible nonlinearities by making use of certain conservation laws associated with the equations. Furthermore, we construct a Lyapunov energy functional, which is locally convex about the uniform state, and prove (global in time) nonlinear dynamic stability of the uniform state for any choice of nonlinearity. We compare the dynamics to that of other problems and discuss open questions concerning a larger range of nonlinearities, for which we conjecture global existence.Comment: 27 Pages, 7 figures are not present in this version. See http://www.columbia.edu/~grs2103/ for a PDF with figures. Submitted to Nonlinearit

Particle characteristics of microplastics contaminating the mussel Mytilus edulis and their surrounding environments

This is the final version. Available on open access from Elsevier via the DOI in this recordWe investigated the environmental partitioning and particle characteristics of macro-, meso- and microplastics and their uptake into the mussel, Mytilus edulis. Sediment samples, overlying seawater and mussels from 9 intertidal locations in the South West of England were analysed for abundance and type of microplastic. Micro- and mesoplastic-like particles were found in 88.5% of the 269 mussels sampled, ranging from 1.43 to 7.64 items per mussel. Of these plastic particles, 70.9% were identified as semi-synthetic (mainly modified-cellulose). Mussel microplastic abundance, but not polymer type, was correlated with that of their surrounding sediment, but not with sea-surface microplastic concentration or mussel size for our study sites. We found significant differences in the relative abundance of polymer types and particle sizes between seawater, sediment, and mussels, with mussels over-representing modified-cellulose fibre abundance but under-representing polyvinyl. Mussels contained significantly smaller plastic fragments than their surrounding sediment and shorter fibres than their overlying seawater

Simple guide to starting a research group

Conducting cutting-edge research and scholarship becomes more complicated with each passing year; forming a collaborative research group offers a way to navigate this increasing complexity. Yet many individuals whose work might benefit from the formation of a collaborative team may feel overwhelmed by the prospect of attempting to build and maintain a research group. We propose this simple guide for starting and maintaining such an enterprise

Regulation of proliferating cell nuclear antigen ubiquitination in mammalian cells

After exposure to DNA-damaging agents that block the progress of the replication fork, monoubiquitination of proliferating cell nuclear antigen (PCNA) mediates the switch from replicative to translesion synthesis DNA polymerases. We show that in human cells, PCNA is monoubiquitinated in response to methyl methanesulfonate and mitomycin C, as well as UV light, albeit with different kinetics, but not in response to bleomycin or camptothecin. Cyclobutane pyrimidine dimers are responsible for most of the PCNA ubiquitination events after UV-irradiation. Failure to ubiquitinate PCNA results in substantial sensitivity to UV and methyl methanesulfonate, but not to camptothecin or bleomycin. PCNA ubiquitination depends on Replication Protein A (RPA), but is independent of ATR-mediated checkpoint activation. After UV-irradiation, there is a temporal correlation between the disappearance of the deubiquitinating enzyme USP1 and the presence of PCNA ubiquitination, but this correlation was not found after chemical mutagen treatment. By using cells expressing photolyases, we are able to remove the UV lesions, and we show that PCNA ubiquitination persists for many hours after the damage has been removed. We present a model of translesion synthesis behind the replication fork to explain the persistence of ubiquitinated PCNA