Global late Quaternary megafauna extinctions linked to humans, not climate change

The late Quaternary megafauna extinction was a severe global-scale event. Two factors, climate change and modern humans, have received broad support as the primary drivers, but their absolute and relative importance remains controversial. To date, focus has been on the extinction chronology of individual or small groups of species, specific geographical regions or macroscale studies at very coarse geographical and taxonomic resolution, limiting the possibility of adequately testing the proposed hypotheses. We present, to our knowledge, the first global analysis of this extinction based on comprehensive country-level data on the geographical distribution of all large mammal species (more than or equal to 10 kg) that have gone globally or continentally extinct between the beginning of the Last Interglacial at 132 000 years BP and the late Holocene 1000 years BP, testing the relative roles played by glacial–interglacial climate change and humans. We show that the severity of extinction is strongly tied to hominin palaeobiogeography, with at most a weak, Eurasia-specific link to climate change. This first species-level macroscale analysis at relatively high geographical resolution provides strong support for modern humans as the primary driver of the worldwide megafauna losses during the late Quaternary

Next-to-leading order QCD predictions for W+W+jj production at the LHC

Because the LHC is a proton-proton collider, sizable production of two positively charged W-bosons in association with two jets is possible. This process leads to a distinct signature of same sign high-pt leptons, missing energy and jets. We compute the NLO QCD corrections to the QCD-mediated part of pp -> W+W+jj. These corrections reduce the dependence of the production cross-section on the renormalization and factorization scale to about +- 10 percent. We find that a large number of W+W+jj events contain a relatively hard third jet. The presence of this jet should help to either pick up the W+W+jj signal or to reject it as an unwanted background.Comment: 15 pages, 5 (lovely) figures, v3 accepted for publication in JHEP, corrects tables in appendi

The medium-term sustainability of organisational innovations in the national health service

Background: There is a growing recognition of the importance of introducing new ways of working into the UK's National Health Service (NHS) and other health systems, in order to ensure that patient care is provided as effectively and efficiently as possible. Researchers have examined the challenges of introducing new ways of working-'organisational innovations'-into complex organisations such as the NHS, and this has given rise to a much better understanding of how this takes place-and why seemingly good ideas do not always result in changes in practice. However, there has been less research on the medium-and longer-term outcomes for organisational innovations and on the question of how new ways of working, introduced by frontline clinicians and managers, are sustained and become established in day-to-day practice. Clearly, this question of sustainability is crucial if the gains in patient care that derive from organisational innovations are to be maintained, rather than lost to what the NHS Institute has called the 'improvement-evaporation effect'. Methods: The study will involve research in four case-study sites around England, each of which was successful in sustaining its new model of service provision beyond an initial period of pilot funding for new genetics services provided by the Department of Health. Building on findings relating to the introduction and sustainability of these services already gained from an earlier study, the research will use qualitative methods-in-depth interviews, observation of key meetings, and analysis of relevant documents-to understand the longer-term challenges involved in each case and how these were surmounted. The research will provide lessons for those seeking to sustain their own organisational innovations in wide-ranging clinical areas and for those designing the systems and organisations that make up the NHS, to make them more receptive contexts for the sustainment of innovation. Discussion: Through comparison and contrast across four sites, each involving different organisational innovations, different forms of leadership, and different organisational contexts to contend with, the findings of the study will have wide relevance. The research will produce outputs that are useful for managers and clinicians responsible for organisational innovation, policy makers and senior managers, and academics

The treatment of the infrared region in perturbative QCD

We discuss the contribution coming from the infrared region to NLO matrix elements and/or coefficient functions of hard QCD processes. Strictly speaking, this contribution is not known theoretically, since it is beyond perturbative QCD. For DGLAP evolution all the infrared contributions are collected in the phenomenological input parton distribution functions (PDFs), at some relatively low scale Q_0; functions which are obtained from a fit to the `global' data. However dimensional regularization sometimes produces a non-zero result coming from the infrared region. Instead of this conventional regularization treatment, we argue that the proper procedure is to first subtract from the NLO matrix element the contribution already generated at the same order in \alpha_s by the LO DGLAP splitting function convoluted with the LO matrix element. This prescription eliminates the logarithmic infrared divergence, giving a well-defined result which is consistent with the original idea that everything below Q_0 is collected in the PDF input. We quantify the difference between the proposed treatment and the conventional approach using low-mass Drell-Yan production and deep inelastic electron-proton scattering as examples; and discuss the potential impact on the `global' PDF analyses. We present arguments to show that the difference cannot be regarded as simply the use of an alternative factorization scheme.Comment: 15 pages, 5 figures, title changed, text considerably modified to improve presentation, and discussion section enlarge

Mitigating agency risk between investors and ventures’ managers

The general management literature has long focused on the agency risks involved in the relationship between general managers and shareholders. Shareholders can deploy contractual and non-contractual mechanisms to reduce these inefficiencies. This study examines - based on a broad international sample of investment contracts - how the use of contractual and non-contractual mechanisms is related to the degree of risks associated with the venture’s development stage as well as how these practices differ across countries. Hypotheses are tested using a proprietary dataset of 265 hand-collected investment contracts associated with ventures in the U.S., Israel and nine European countries. Findings suggest that the use of mitigating contractual and non-contractual mechanisms is related to the degree of agency risks, and that these practices vary across countries. This study draws implications for how investors can best deploy their capital in different institutional settings whilst nurturing their relationships with managers and entrepreneurs

SARS and hospital priority setting: a qualitative case study and evaluation

BACKGROUND: Priority setting is one of the most difficult issues facing hospitals because of funding restrictions and changing patient need. A deadly communicable disease outbreak, such as the Severe Acute Respiratory Syndrome (SARS) in Toronto in 2003, amplifies the difficulties of hospital priority setting. The purpose of this study is to describe and evaluate priority setting in a hospital in response to SARS using the ethical framework 'accountability for reasonableness'. METHODS: This study was conducted at a large tertiary hospital in Toronto, Canada. There were two data sources: 1) over 200 key documents (e.g. emails, bulletins), and 2) 35 interviews with key informants. Analysis used a modified thematic technique in three phases: open coding, axial coding, and evaluation. RESULTS: Participants described the types of priority setting decisions, the decision making process and the reasoning used. Although the hospital leadership made an effort to meet the conditions of 'accountability for reasonableness', they acknowledged that the decision making was not ideal. We described good practices and opportunities for improvement. CONCLUSIONS: 'Accountability for reasonableness' is a framework that can be used to guide fair priority setting in health care organizations, such as hospitals. In the midst of a crisis such as SARS where guidance is incomplete, consequences uncertain, and information constantly changing, where hour-by-hour decisions involve life and death, fairness is more important rather than less

Age-related differences in adaptation during childhood: The influences of muscular power production and segmental energy flow caused by muscles

Acquisition of skillfulness is not only characterized by a task-appropriate application of muscular forces but also by the ability to adapt performance to changing task demands. Previous research suggests that there is a different developmental schedule for adaptation at the kinematic compared to the neuro-muscular level. The purpose of this study was to determine how age-related differences in neuro-muscular organization affect the mechanical construction of pedaling at different levels of the task. By quantifying the flow of segmental energy caused by muscles, we determined the muscular synergies that construct the movement outcome across movement speeds. Younger children (5-7 years; n = 11), older children (8-10 years; n = 8), and adults (22-31 years; n = 8) rode a stationary ergometer at five discrete cadences (60, 75, 90, 105, and 120 rpm) at 10% of their individually predicted peak power output. Using a forward dynamics simulation, we determined the muscular contributions to crank power, as well as muscular power delivered to the crank directly and indirectly (through energy absorption and transfer) during the downstroke and the upstroke of the crank cycle. We found significant age × cadence interactions for (1) peak muscular power at the hip joint [Wilks' Lambda = 0.441, F(8,42) = 2.65, p = 0.019] indicating that at high movement speeds children produced less peak power at the hip than adults, (2) muscular power delivered to the crank during the downstroke and the upstroke of the crank cycle [Wilks' Lambda = 0.399, F(8,42) = 3.07, p = 0.009] indicating that children delivered a greater proportion of the power to the crank during the upstroke when compared to adults, (3) hip power contribution to limb power [Wilks' Lambda = 0.454, F(8,42) = 2.54, p = 0.023] indicating a cadence-dependence of age-related differences in the muscular synergy between hip extensors and plantarflexors. The results demonstrate that in spite of a successful performance, children construct the task of pedaling differently when compared to adults, especially when they are pushed to their performance limits. The weaker synergy between hip extensors and plantarflexors suggests that a lack of inter-muscular coordination, rather than muscular power production per se, is a factor that limits children's performance ranges