2,695 research outputs found
R&D Spillovers and the Case for Industrial Policy in an Open Economy
In this paper we consider the case for subsidies towards firms which generate R&D spillovers in open economies. We show that many expected results are overturned in the presence of strategic behaviour by firms. Local R&D spillovers to other domestic firms may justify an R&D tax rather than a subsidy; R&D cooperation by local firms over-internalises the externality and also justifies an R&D tax; and international spillovers which benefit foreign firms may justify a subsidy, even though the government cares only about the profits of home firms.
Comparing the Ancient Star Formation Histories of the Magellanic Clouds
We present preliminary results from a new HST archival program aimed at
tightly constraining the ancient (>4 Gyr ago) star formation histories (SFHs)
of the field populations of the SMC and LMC. We demonstrate the quality of the
archival data by constructing HST/WFPC2-based color-magnitude diagrams (CMDs;
M_{F555W} ~ +8) for 7 spatially diverse fields in the SMC and 8 fields in the
LMC. The HST-based CMDs are >2 magnitudes deeper than any from ground based
observations, and are particularly superior in high surface brightness regions,
e.g., the LMC bar, which contain a significant fraction of star formation and
are crowding limited from ground based observations. To minimize systematic
uncertainties, we derive the SFH of each field using an identical maximum
likelihood CMD fitting technique. We then compute an approximate mass weighted
average SFH for each galaxy. We find that both galaxies lack a dominant burst
of early star formation, which suggests either a suppression or an
under-fueling of early star formation. From 10-12 Gyr ago, the LMC experienced
a period of enhanced stellar mass growth relative to the SMC. Similar to some
previous studies, we find two notable peaks in the SFH of the SMC at ~4.5 and 9
Gyr ago, which could be due to repeated close passages with the LMC, implying
an interaction history that has persisted for at least 9 Gyr. We find little
evidence for strong periodic behavior in the lifetime SFHs of both MCs,
suggesting that repeated encounters with the Milky Way are unlikely. Beginning
~3.5 Gyr ago, both galaxies show increases in their SFHs, in agreement with
previous studies, and thereafter, track each other remarkably well. (abridged)Comment: 9 pages, 5 Figures, Accepted for Publication in MNRA
Saltation under Martian Gravity and its Influence on the Global Dust Distribution
Dust and sand motion are a common sight on Mars. Understanding the
interaction of atmosphere and Martian soil is fundamental to describe the
planet's weather, climate and surface morphology.
We set up a wind tunnel to study the lift of a mixture between very fine sand
and dust in a Mars simulant soil. The experiments were carried out under
Martian gravity in a parabolic flight. The reduced gravity was provided by a
centrifuge under external microgravity. The onset of saltation was measured for
a fluid threshold shear velocity of 0.820.04 m/s. This is considerably
lower than found under Earth gravity.
In addition to a reduction in weight, this low threshold can be attributed to
gravity dependent cohesive forces within the sand bed, which drop by 2/3 under
Martian gravity. The new threshold for saltation leads to a simulation of the
annual dust cycle with a Mars GCM that is in agreement with observations
Bailouts in a common market: a strategic approach
Governments in the EU grant Rescue and Restructure Subsidies to bail out ailing firms. In an international asymmetric Cournot duopoly we study effects of such subsidies on market structure and welfare. We adopt a common market setting, where consumers from the two countries form one market. We show that the subsidy is positive also when it fails to prevent the exit. The reason is a strategic effect, which forces the more efficient firm to make additional cost-reducing effort. When the exit is prevented, allocative and productive efficiencies are lower and the only gaining player is the rescued firm
Strike, occupy, transform! Students, subjectivity and struggle
This article uses student activism to explore the way in which activists are challenging the student as consumer model through a series of experiments that blend pedagogy and protest. Specifically, I suggest that Higher Education is increasingly becoming an arena of the postpolitical, and I argue that one of the ways this student-consumer subjectivity is being (re)produced is through a series of ‘depoliticisation machines’ operating within the university. This article goes on to claim that in order to counter this, some of those resisting the neoliberalisation of higher education have been creating political-pedagogical experiments that act as ‘repoliticisation machines’, and that these experiments countered student-consumer subjectification through the creation of new radical forms of subjectivity. This paper provides an example of this activity through the work of a group called the Really Open University and its experiments at blending, protest, pedagogy and propaganda
Does the revised cardiac risk index predict cardiac complications following elective lung resection?
Background:
Revised Cardiac Risk Index (RCRI) score and Thoracic Revised Cardiac Risk Index (ThRCRI) score were developed to predict the risks of postoperative major cardiac complications in generic surgical population and thoracic surgery respectively. This study aims to determine the accuracy of these scores in predicting the risk of developing cardiac complications including atrial arrhythmias after lung resection surgery in adults.
Methods:
We studied 703 patients undergoing lung resection surgery in a tertiary thoracic surgery centre. Observed outcome measures of postoperative cardiac morbidity and mortality were compared against those predicted by risk.
Results:
Postoperative major cardiac complications and supraventricular arrhythmias occurred in 4.8% of patients. Both index scores had poor discriminative ability for predicting postoperative cardiac complications with an area under receiver operating characteristic (ROC) curve of 0.59 (95% CI 0.51-0.67) for the RCRI score and 0.57 (95% CI 0.49-0.66) for the ThRCRI score.
Conclusions:
In our cohort, RCRI and ThRCRI scores failed to accurately predict the risk of cardiac complications in patients undergoing elective resection of lung cancer. The British Thoracic Society (BTS) recommendation to seek a cardiology referral for all asymptomatic pre-operative lung resection patients with > 3 RCRI risk factors is thus unlikely to be of clinical benefit
On acceptance conditions for membrane systems: characterisations of L and NL
In this paper we investigate the affect of various acceptance conditions on
recogniser membrane systems without dissolution. We demonstrate that two
particular acceptance conditions (one easier to program, the other easier to
prove correctness) both characterise the same complexity class, NL. We also
find that by restricting the acceptance conditions we obtain a characterisation
of L. We obtain these results by investigating the connectivity properties of
dependency graphs that model membrane system computations
The ‘Blueprint’ framework for career management skills: a critical exploration
This article examines the Blueprint framework for career management skills as it has been revealed across sequential implementations in the USA, Canada and Australia. It is argued that despite its lack of an empirical basis, the framework forms a useful and innovative means through which career theory, practice and policy can be connected. The framework comprises both core elements (learning areas, learning model and levels) and contextual elements (resources, community of practice, service delivery approach and policy connection). Each of these elements is explored
Cell cycle regulation of astrocytes by extracellular nucleotides and fibroblast growth factor-2
Extracellular ATP enhances the mitogenic activity of fibroblast growth factor-2 (FGF2) in astrocytes, but the molecular mechanism underlying this synergistic interaction is not known. To determine whether the potentiating effect of extracellular ATP involves cell cycle control mechanisms, we have measured the expression of cyclins that are induced in different phases of the cell cycle in primary cultures of rat cortical astrocytes. We found that ATP potentiated the ability of FGF2 to stimulate expression of cyclin D1, a regulator of cell cycle entry, as well as cyclin A, a regulator of DNA replication. Because FGF2 and P2 purinergic receptors are coupled to extracellular signal regulated protein kinase (ERK), a key member of a signaling cascade that regulates proliferation, we also investigated the role of ERK in regulating cyclin expression induced by FGF2 and ATP. We found that the potentiating effect of ATP on cyclin expression was significantly reduced by U0126, an inhibitor of MEK, the upstream activator of ERK. P2 receptor agonist studies revealed that UTP enhanced FGF2-induced cyclin expression and mitogenesis whereas 2-methylthioADP was ineffective. By contrast, 2-3-O-(4-benzoyl)-benzoyl-ATP markedly inhibited FGF2-induced mitogenesis. Consistent with opposing effects of P2Y and P2X receptors on mitogenesis, UTP stimulated a transient activation of ERK whereas BzATP stimulated a more sustained ERK signal. These findings suggest that signaling by P2Y receptors, most likely of the purine/pyrimidine subtype, enhance the ability of FGF2 to stimulate entry into a new cell cycle, as well as DNA replication, by an ERK-dependent mechanism, whereas signaling by P2X receptors, possibly the P2X7 subtype, inhibits FGF2-induced mitogenesis in astrocytes. Interactions between P2Y, P2X and polypeptide growth factor signaling pathways may have important implications for CNS development as well as injury and repair
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