28,420 research outputs found
Balancing contractual and relational approaches for PPP success and sustainability
Useful synergies are targeted by proposing a convergence of hitherto parallel international endeavours towards: (1) developing better and sustainable relationships for more productive construction project teams, in general; and (2) optimising the necessarily long term contractual arrangements of PPPs in particular. Examples are drawn from Africa and Latin America to reinforce reported PPP experiences from other regions, in building up a case for injecting ârelational contracting approachesâ in order to develop more productive and sustainable PPPs. Strong and sustainable relationships are shown to be essential, and complementary to appropriate contractual incentives, that would together empower PPP project teams to focus on developing sustainable infrastructure and ultimately on overall sustainable development. These propositions are merged into a basic model that merits further investigation and development, in order to ensure that planned PPPs benefit the community at large, in respect of both present and future generations
Helicity-1/2 Mode as a Probe of Interactions of Massive Rarita-Schwinger Field
We consider the electromagnetic and gravitational interactions of a massive
Rarita-Schwinger field. Stueckelberg analysis of the system, when coupled to
electromagnetism in flat space or to gravity, reveals in either case that the
effective field theory has a model-independent upper bound on its UV cutoff,
which is finite but parametrically larger than the particle's mass. It is the
helicity-1/2 mode that becomes strongly coupled at the cutoff scale. If the
interactions are inconsistent, the same mode becomes a telltale sign of
pathologies. Alternatively, consistent interactions are those that propagate
this mode within the light cone. Studying its dynamics not only sheds light on
the Velo-Zwanziger acausality, but also elucidates why supergravity and other
known consistent models are pathology-free.Comment: 18 pages, cutoff analysis improved, to appear in PR
Solution of Linear Programming Problems using a Neural Network with Non-Linear Feedback
This paper presents a recurrent neural circuit for solving linear programming problems. The objective is to minimize a linear cost function subject to linear constraints. The proposed circuit employs non-linear feedback, in the form of unipolar comparators, to introduce transcendental terms in the energy function ensuring fast convergence to the solution. The proof of validity of the energy function is also provided. The hardware complexity of the proposed circuit compares favorably with other proposed circuits for the same task. PSPICE simulation results are presented for a chosen optimization problem and are found to agree with the algebraic solution. Hardware test results for a 2âvariable problem further serve to strengthen the proposed theory
How Vulnerable are Bangladeshâs Indigenous People to Climate Change?
This paper compares the vulnerabilities to climate change and climate variability of the indigenous people with the Bengali population of Bangladesh. It distinguishes between (a) individual vulnerabilities that are related to an individualâs capability to adapt to climate change and; (b) spatial vulnerabilities, that is, vulnerabilities that are related to the location of a person (like the exposure to climate change-induced disasters). While an individualâs capability to adapt to climate change is determined by many factors, some relatively simple approximation is to look at poverty, landlessness, and illiteracy. Spatial vulnerabilities are reviewed by looking at drought hazard maps, flood hazard maps, landslide hazard maps, and cyclone hazard maps. Hence, the paper compares levels of poverty, landlessness, illiteracy, and the more direct though also more subjective exposures to increased droughts, floods, landslides, and cyclones across the two population groups. The paper concludes with some broad suggestions on adaptation strategies of indigenous people as well as suggestions for policy interventions to reduce climate change-induced vulnerabilities for indigenous people in the Chittagong Hill Tracts (CHT).Bangladesh, climate change, vulnerability
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