108 research outputs found
Durational exposure-dependent effect of carbamate treated net on hepatic and renal functions in Wistar rats
Assessment of the duration exposure-dependent effect of carbamate treated net on hepatic and renal functions of albino Wistar rats after 30 and 60 days was carried out. Serum ALT, AST and ALP levels were determined to assess liver function while serum creatinine and urea levels were measured for kidney function. Eighteen (18) male albino Wstar rats weighing 138-146g were divided into 3 groups of 6 rats each. Group 1 served as control, group 2 animals were exposed to carbamate treated net for 30 days and group 3 animals exposed for 60 days. The results showed that the levels of serum AST and ALT increased in all the experimental groups exposed when compared to the control group. ALT increased significantly (p<0.05) in the rats exposed for 60 days (203.83±0.307) while AST increased highest in experimental groups exposed for 30 days (203± 1.613)and 60 days (362± 0.365) respectively when compared to the control (150.5±0.34). ALP increased significantly (p<0.05) only in the group exposed for 30 days (17.67±0.21),but decreased in the group exposed for 60 days when compared to the control group. Serum creatinine increased insignificantly (p>0.05) in the group exposed for 30 days but decreased in the group exposed for 60 days while serum urea level in the group exposed for 30 days remain unchanged but decreased after 60 days when compared to the control group. Statistically, there was a significant increase (p<0.05) in body weight and organ weight of the animals exposed for 30 and 60 days. Therefore, this present study demonstrates that exposure to carbamate treated net may alter the integrity and function of liver thereby causing hepatotoxicity while the exposure of rats to carbamate treated net may not pose any significant nephrotoxicity in rats
Completeness of classical spin models and universal quantum computation
We study mappings between distinct classical spin systems that leave the
partition function invariant. As recently shown in [Phys. Rev. Lett. 100,
110501 (2008)], the partition function of the 2D square lattice Ising model in
the presence of an inhomogeneous magnetic field, can specialize to the
partition function of any Ising system on an arbitrary graph. In this sense the
2D Ising model is said to be "complete". However, in order to obtain the above
result, the coupling strengths on the 2D lattice must assume complex values,
and thus do not allow for a physical interpretation. Here we show how a
complete model with real -and, hence, "physical"- couplings can be obtained if
the 3D Ising model is considered. We furthermore show how to map general
q-state systems with possibly many-body interactions to the 2D Ising model with
complex parameters, and give completeness results for these models with real
parameters. We also demonstrate that the computational overhead in these
constructions is in all relevant cases polynomial. These results are proved by
invoking a recently found cross-connection between statistical mechanics and
quantum information theory, where partition functions are expressed as quantum
mechanical amplitudes. Within this framework, there exists a natural
correspondence between many-body quantum states that allow universal quantum
computation via local measurements only, and complete classical spin systems.Comment: 43 pages, 28 figure
The role of government co-investment funds in the supply of entrepreneurial finance: An assessment of the early operation of the UK Angel Co-investment Fund
Co-investment funds – which invest alongside private investors, especially business angels – thereby leveraging their networks and experience and minimizing public sector transaction costs – are a recent approach by governments in various countries to address the early stage entrepreneurial funding gap which is perceived as a barrier to the ability of firms to scale-up. However, little literature exists on their operation, impact and effectiveness. This paper assesses the early operation of the UK’s Angel Co-investment Fund, established in 2011. Interview evidence from angels and business managers suggests that the Angel Co-investment Fund is improving the availability of finance by enabling firms to raise funding rounds of between £500,000 and £2 m, hence addressing some aspects of the broken finance escalator model. However, our evidence suggests that it is not yet impacting the supply side, either in terms of stimulating the formation of new angel groups or enhancing learning amongst less experienced angels. Some aspects of the operation of the investment process have attracted criticism from angels and entrepreneurs which need to be addressed. Nevertheless, there is sufficient evidence for positive impact to justify the scheme’s expansion
Classical Ising model test for quantum circuits
We exploit a recently constructed mapping between quantum circuits and graphs
in order to prove that circuits corresponding to certain planar graphs can be
efficiently simulated classically. The proof uses an expression for the Ising
model partition function in terms of quadratically signed weight enumerators
(QWGTs), which are polynomials that arise naturally in an expansion of quantum
circuits in terms of rotations involving Pauli matrices. We combine this
expression with a known efficient classical algorithm for the Ising partition
function of any planar graph in the absence of an external magnetic field, and
the Robertson-Seymour theorem from graph theory. We give as an example a set of
quantum circuits with a small number of non-nearest neighbor gates which admit
an efficient classical simulation.Comment: 17 pages, 2 figures. v2: main result strengthened by removing
oracular settin
The Molecular Clockwork of the Fire Ant Solenopsis invicta
This is an open-access article, free of all copyright, and may be freely reproduced, distributed, transmitted, modified, built upon, or otherwise used by anyone for any lawful purpose. The work is made available under the Creative Commons CC0 public domain dedication
The transformation of the business angel market: empirical evidence and research implications
Business angel investing – a key source of finance for entrepreneurial businesses – is rapidly evolving from a fragmented and largely anonymous activity dominated by individuals investing on their own to one that is increasingly characterised by groups of investors investing together through managed angel groups. The implications of this change have been largely ignored by scholars. The paper examines the investment activity and operation of angel groups in Scotland to highlight the implications of this change for the nature of angel investing. It goes on to argue that this transformation challenges both the ongoing relevance of prior research on business angels and current methodological practices, and raises a set of new research questions
Belief Propagation and Loop Series on Planar Graphs
We discuss a generic model of Bayesian inference with binary variables
defined on edges of a planar graph. The Loop Calculus approach of [1, 2] is
used to evaluate the resulting series expansion for the partition function. We
show that, for planar graphs, truncating the series at single-connected loops
reduces, via a map reminiscent of the Fisher transformation [3], to evaluating
the partition function of the dimer matching model on an auxiliary planar
graph. Thus, the truncated series can be easily re-summed, using the Pfaffian
formula of Kasteleyn [4]. This allows to identify a big class of
computationally tractable planar models reducible to a dimer model via the
Belief Propagation (gauge) transformation. The Pfaffian representation can also
be extended to the full Loop Series, in which case the expansion becomes a sum
of Pfaffian contributions, each associated with dimer matchings on an extension
to a subgraph of the original graph. Algorithmic consequences of the Pfaffian
representation, as well as relations to quantum and non-planar models, are
discussed.Comment: Accepted for publication in Journal of Statistical Mechanics: theory
and experimen
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