Length-weight relationship of fishes caught by trawl off Alexandria, Egypt

This paper presents the length-weight relationship parameters (a and b) for 29 fish species, belonging to 16 families, taken by otter trawl fishing from Egyptian Mediterranean waters. The b values obtained ranged from 2.50 to 3.44 (with a mean of 2.926)

Climate change, contemporary society and engineering practice: a sustainability journey

[Abstract]: Climate change, Contemporary Society and engineers share an indivisible pathway towards sustainability through the means of technology. Climate change and sustainability are now new domains that require a better understanding by engineers. Ten years ago sustainability was a development for the future however the absence of climate certainty in contemporary society has raised sustainability awareness to the forefront of societal debate. While sustainability in theory is defined as the capacity to maintain a certain process or state indefinitely. However the literal meaning of “indefinitely” in sustainability definition poses a set of intriguing questions, is indefinite human survival a plausible proposition in a finite world. For this reason efforts in the fight against climate change are becoming a global effort, since it requires global cooperation and greater scientific consensus to reduce carbon emissions and consequently the planet’s energy footprint. We recognize that Sustainability ought to be economically viable, ecologically sound and sensitive; socially responsible and culturally appropriate. Surrounded by this realm of thinking all these mentioned definitions are equal measures that fail to address the importance of “technology” as a subject in the climate change and sustainability debate. Since this generation had inherited the historical legacy of nonrenewable energy technologies. The term “technology” in this context implies any technical system that can result in and/or be well described in terms of a process by which humans modify nature to meet their needs and wants. This paper seeks to investigate the underlying philosophical frames and the nature of the issues of sustainability present to engineers. It explores the notion of “Sustainability” and “technology “in engineering practice. Further, we argue that in order to establish a clear, measurable, actionable, and universally accessible working definition of sustainable engineering practices. climate change and technology life cycle need to be inclusive to sustainability

Extremal functions for the anisotropic Sobolev inequalities

The existence of multiple nonnegative solutions to the anisotropic critical problem - \sum_{i=1}^{N} \frac{\partial}{\partial x_i} (| \frac{\partial u}{\partial x_i} |^{p_i-2} \frac{\partial u}{\partial x_i}) = |u|^{p^*-2} u {in} \mathbb{R}^N is proved in suitable anisotropic Sobolev spaces. The solutions correspond to extremal functions of a certain best Sobolev constant. The main tool in our study is an adaptation of the well-known concentration-compactness lemma of P.-L. Lions to anisotropic operators. Futhermore, we show that the set of nontrival solutions \calS is included in $L^\infty(\R^N)$ and is located outside of a ball of radius $\tau >0$ in $L^{p^*}(\R^N)$

Reduced Fine-Tuning in Supersymmetry with R-parity violation

Both electroweak precision measurements and simple supersymmetric extensions of the standard model prefer a mass of the Higgs boson less than the experimental lower limit of 114 GeV. We show that supersymmetric models with R parity violation and baryon number violation have a significant range of parameter space in which the Higgs dominantly decays to six jets. These decays are much more weakly constrained by current LEP analyses and would allow for a Higgs mass near that of the $Z$. In general, lighter scalar quark and other superpartner masses are allowed and the fine-tuning typically required to generate the measured scale of electroweak symmetry breaking is ameliorated. The Higgs would potentially be discovered at hadron colliders via the appearance of new displaced vertices. The lightest neutralino could be discovered by a scan of vertex-less events LEP I data.Comment: 5 pages, 2 figures. Significant detail added to the arguments regarding LEP limits - made more quantitative. Better figures used, plotting more physical quantities. Typos corrected and references updated. Conclusions unchange