685 research outputs found
A Future Vision For The Engineering Design Environment: A Future Sociotechnical Scenario
No full textThis paper presents a future vision for the working practices of designers within a manufacturing organisation. By its very nature the engineering design environment is highly distributed in nature and is characterised by a large number of information sources, which together with the designers forms a complex sociotechnical system. In discussions with designers it is apparent that changes are required to this environment to reflect the changes in the design process and organisations. We have developed a scenario that incorporates many of the features requested by designers and managers to improve the design environment. The scenario sets out a route map for the development of technical and social tools that aid the designer
Recession, International Trade and the Fallacies of Composition
No full textA truly global recession has not been manifest since the Great Depression of the 1930s. As a result, the multilateral institutions put in place at the end of the Second World War to ensure that a major depression never happened again have not been tested. One of the lessons of the Great Depression was that governments had a major role to play in managing the economy. The use of subsidies to affect economic outcomes was one manifestation of this expanded role. In a recession, sector specific subsidies will likely be requested by firms. Subsidies can distort trade, leading to the potential for beggar thy neighbour subsidy wars. Subsidies will be difficult to discipline in a global recession.beggar thy neighbour, deficits, paradox of thrift, recession, subsidies, International Relations/Trade,
Race for the Kerr field
No full textRoy P. Kerr has discovered his celebrated metric 45 years ago, yet the problem to find a generalization of the Schwarzschild metric for a rotating mass was faced much earlier. Lense and Thirring, Bach, Andress, Akeley, Lewis, van Stockum and others have tried to solve it or to find an approximative solution at least. In particular Achilles Papapetrou, from 1952 to 1961 in Berlin, was interested in an exact solution. He directed the author in the late autumn of 1959 to work on the problem. Why did these pre-Kerr attempts fail? Comments based on personal reminiscences and old notes
Microwave and RF photonic applications of integrated Kerr micro-combs
No full textWe report applications of integrated Kerr micro-combs to RF photonic systems and demonstrate a wide range of advanced functions including a microwave photonic intensity differentiator, filters and true time delays. The on-chip Kerr optical comb is CMOS-compatible and serves as a high-performance multi-wavelength source for transversal filter functions, thus greatly reducing the cost, size, and complexity of the system. © 2018 The Author(s).</p
Political Precaution, Pandemics and Protectionism
No full textDespite strong scientific evidence and representations made by international scientific organizations, a considerable number of countries have imposed import bans on pork in response to the H1N1 pandemic. The imposition of these barriers is contrary to WTO rules. The motivation for the imposition of these barriers does not appear to have arisen from producers’ requests or consumer lobbying – political precaution provides the motivation. There appears to be little control over political precaution in the rules of international trade. Hence, the balance between the strong rules of trade desired by firms wishing to engage in international commerce and the need, at times, for politicians to respond to requests for protection may be changing in favour of more protection. Keywords: H1N1, import bans, pork, precaution, protection, swineH1N1, import bans, pork, precaution, protection, swine, Food Consumption/Nutrition/Food Safety, Health Economics and Policy, International Relations/Trade, Livestock Production/Industries, Political Economy, Public Economics, Risk and Uncertainty,
Polynomial rings over Goldie-Kerr commutative rings
No full textAll rings in this paper are commutative, and
acc
⊥
\operatorname {acc} \bot
(resp.,
acc
⊕
\operatorname {acc} \, \oplus
) denotes the acc on annihilators (resp., on direct sums of ideals). Any subring of an
acc
⊥
\operatorname {acc} \bot
ring, e.g., of a Noetherian ring, is an
acc
⊥
\operatorname {acc} \bot
ring. Together,
acc
⊥
\operatorname {acc} \bot
and
acc
⊕
\operatorname {acc} \, \oplus
constitute the requirement for a ring to be a Goldie ring. Moreover, a ring
R
R
is Goldie iff its classical quotient ring
Q
Q
is Goldie. A ring
R
R
is a Kerr ring (the appellation is for J. Kerr, who in 1990 constructed the first Goldie rings not Kerr) iff the polynomial ring
R
[
x
]
R[x]
has
acc
⊥
\operatorname {acc} \bot
(in which case
R
R
must have
acc
⊥
\operatorname {acc} \bot
). By the Hilbert Basis theorem, if
S
S
is a Noetherian ring, then so is
S
[
x
]
S[x]
; hence, any subring
R
R
of a Noetherian ring is Kerr. In this note, using results of Levitzki, Herstein, Small, and the author, we show that any Goldie ring
R
R
such that
Q
=
Q
c
(
R
)
Q = {Q_c}(R)
has nil Jacobson radical (equivalently, the nil radical of
R
R
is an intersection of associated prime ideals) is Kerr in a very strong sense:
Q
Q
is Artinian and, hence, Noetherian (Theorems 1.1 and 2.2). As a corollary we prove that any Goldie ring
A
A
that is algebraic over a field
k
k
is Artinian, and, hence, any order
R
R
in
A
A
is a Kerr ring (Theorem 2.5 and Corollary 2.6). The same is true of any algebra
A
A
over a field
k
k
of cardinality exceeding the dimension of
A
A
(Corollary 2.7). Other Kerr rings are: reduced
acc
⊥
\operatorname {acc} \bot
rings and valuation rings with
acc
⊥
\operatorname {acc} \bot
(see 3.3 and 3.4).</p
A qualitative study of shift handover practice and function from a socio‐technical perspective
No full textSpectral multiplexing of dissipative Kerr solitons in a single optical microresonator
No full textWe experimentally demonstrate that dissipative Kerr solitons generated in different spectral regions can stably coexist in a single optical microresonator enabling spectral multiplexing of soliton microcombs. (C) 2020 The Author(s)LPQ
Hawking radiation from general Kerr-(anti)de Sitter black holes
No full textWe calculate the total flux of Hawking radiation from Kerr-(anti)de Sitter black holes by using gravitational anomaly method developed in [S. P. Robinson and F. Wilczek, Phys. Rev. Lett. 95, 011303 (2005)]. We consider the general Kerr-(anti)de Sitter black holes in arbitrary D dimensions with the maximal number [D/2] of independent rotating parameters. We find that the physics near the horizon can be described by an infinite collection of (1+1)-dimensional quantum fields coupled to a set of gauge fields with charges proportional to the azimuthal angular momentums m(i). With the requirement of anomaly cancellation and regularity at the horizon, the Hawking radiation is determined.Astronomy & AstrophysicsPhysics, Particles & FieldsSCI(E)0ARTICLE2null7
A role for ABCB1 in prognosis, invasion and drug resistance in ependymoma
No full text© 2019, The Author(s). Three of the hallmarks of poor prognosis in paediatric ependymoma are drug resistance, local invasion and recurrence. We hypothesised that these hallmarks were due to the presence of a sub-population of cancer stem cells expressing the multi-drug efflux transporter ABCB1. ABCB1 gene expression was observed in 4 out of 5 paediatric ependymoma cell lines and increased in stem cell enriched neurospheres. Functional inhibition of ABCB1 using vardenafil or verapamil significantly (p ≤ 0.05–0.001) potentiated the response to three chemotherapeutic drugs (vincristine, etoposide and methotrexate). Both inhibitors were also able to significantly reduce migration (p ≤ 0.001) and invasion (p ≤ 0.001). We demonstrate that ABCB1 positive patients from an infant chemotherapy-led trial (CNS9204) had a shorter mean event free survival (EFS) (2.7 versus 8.6 years; p = 0.007 log-rank analysis) and overall survival (OS) (5.4 versus 12 years; p = 0.009 log-rank analysis). ABCB1 positivity also correlated with reduced event free survival in patients with incompletely resected tumours who received chemotherapy across CNS9204 and CNS9904 (a radiotherapy-led SIOP 1999-04 trial cohort; p = 0.03). ABCB1 is a predictive marker of chemotherapy response in ependymoma patients and vardenafil, currently used to treat paediatric pulmonary hypertension in children, could be repurposed to reduce chemoresistance, migration and invasion in paediatric ependymoma patients at non-toxic concentrations
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