Tulane University

About: Tulane University is a education organization based out in New Orleans, Louisiana, United States. It is known for research contribution in the topics: Population & Blood pressure. The organization has 24478 authors who have published 47205 publications receiving 1944993 citations. The organization is also known as: University of Louisiana.

The 'Unreasonable Effectiveness' of Stratigraphic and Geomorphic Experiments

Abstract: The growth of quantitative analysis and prediction in Earth-surface science has been accompanied by growth in experimental stratigraphy and geomorphology. Experimenters have grown increasingly bold in targeting landscape elements from channel reaches up to the entire erosional networks and depositional basins, often using very small facilities. The experiments produce spatial structure and kinematics that, although imperfect, compare well with natural systems despite differences of spatial scale, time scale, material properties, and number of active processes. Experiments have been particularly useful in studying a wide range of forms of self-organized (autogenic) complexity that occur in morphodynamic systems. Autogenic dynamics creates much of the spatial structure we see in the landscape and in preserved strata, and is strongly associated with sediment storage and release. The observed consistency between experimental and field systems despite large differences in governing dimensionless numbers is what we mean by “unreasonable effectiveness”. We suggest that unreasonable experimental effectiveness arises from natural scale independence. We generalize existing ideas to relate internal similarity, in which a small part of a system is similar to the larger system, to external similarity, in which a small copy of a system is similar to the larger system. We propose that internal similarity implies external similarity, though not the converse. The external similarity of landscape experiments to natural landscapes suggests that natural scale independence may be even more characteristic of morphodynamics than it is of better studied cases such as turbulence. We urge a shift in emphasis in experimental stratigraphy and geomorphology away from classical dynamical scaling and towards a quantitative understanding of the origins and limits of scale independence. Other research areas with strong growth potential in experimental surface dynamics include physical–biotic interactions, cohesive effects, stochastic processes, the interplay of structural and geomorphic self-organization, extraction of quantitative process information from landscape and stratigraphic records, and closer interaction between experimentation and theory.

Sex differences in metabolic homeostasis, diabetes, and obesity.

Abstract: There are fundamental aspects of the control of metabolic homeostasis that are regulated differently in males and females. This sex asymmetry represents an evolutionary paradigm for females to resist the loss of energy stores. This perspective discusses the most fundamental sex differences in metabolic homeostasis, diabetes, and obesity. Together, the role of genetic sex, the programming effect of testosterone in the prenatal period in males, and the activational role of sex hormones at puberty produce two different biological systems in males and females that need to be studied separately. These sex-specific differences in energy homeostasis and metabolic dysfunction represent an untested source of factors that can be harnessed to develop relevant sex-based therapeutic avenues for diabetes, metabolic syndrome, and obesity.

A model for evaluating IT security investments

Abstract: A ssessing the return on investment has always been a sticking point for technology investments. Similar to IT productivity paradox [1], Return on Security Investment (ROSI) has become a controversial topic due to immense growth of e-businesses. Defining the value of security investments is challenging. However, it is clear that “security consumers will need to understand the variables that define ROSI and endure the discomfort of assigning dollar values to quantities that currently are extremely ill-defined” [12]. While calculating ROSI seems taxing, increasing possibility and scope of IT security breaches due to increasing interconnectivity makes it imperative. As the number of security breaches increases exponentially according to the CERT (see Table 1) so does their cost. The 2003 CSI/FBI Computer Crime and Security Survey revealed that 56% of respondents detected security breaches. Information Week and PricewaterhouseCoopers LLP estimated that computer viruses and hacking took a $1.6 trillion toll on the worldwide economy and $266 billion in the U.S. [5]. Security breaches have a significant impact on the market values of firms too. We have estimated that compromised firms, on average, lost approximately 2.1% of their market values within two days surrounding security breaches [3]. This translates to an average loss of $1.65 billion in market capitalization per incident. Moitra and Konda [10] found that as investment in security increases the survivability of firms from security breaches increases rapidly at first and then more slowly at higher levels of investment. Undoubtedly these figures point to the importance of more studies on the economics and management of IT security investments. Fear, uncertainty, and doubt (FUD) strategy has been used for years to sell investments in security [1]. However, according to Earthlink security experts Lisa Ekman and Lisa Hoyt, “Crying wolf may get the first firewall, but over the long run, you need a more well-rounded perspective” [12]. Since diverse security techA Model for Evaluating IT Security Investments

Live attenuated, multiply deleted simian immunodeficiency virus causes AIDS in infant and adult macaques

Abstract: A substantial risk in using live attenuated, multiply deleted viruses as vaccines against AIDS is their potential to induce AIDS. A mutant of the simian immunodeficiency virus (SIV) with large deletions in nef and vpr and in the negative regulatory element induced AIDS in six of eight infant macaques vaccinated orally or intravenously. Early signs of immune dysfunction were seen in the remaining two offspring. Prolonged follow-up of sixteen vaccinated adult macaques also showed resurgence of chronic viremia in four animals: two of these developed early signs of disease and one died of AIDS. We conclude that this multiply deleted SIV is pathogenic and that human AIDS vaccines built on similar prototypes may cause AIDS.