Extent and toxicity of contaminated marine sediments in Southeastern Florida

Thirty sites were sampled in southern Biscayne Bay and Manatee Bay in December 1999 to determine the extent of toxicity in sediments. Analyses and assays included: pesticides and phenols in seawater; chemical contaminants in sediment; amphipod mortality, HRGS P450, sea urchin sperm fertilization and embryology, MicrotoxTM, MutatoxTM, grass shrimp AChE and juvenile clam mortality assays; sea urchin sperm, amphipod and oyster DNA damage; and benthic community assessment. Sediment sites near the mouth of canals showed evidence of contamination. Contaminant plumes and associated toxicity do not appear to extend seaward of the mouth of the canals in an appreciable manner. Concentrations of contaminants in the sediments in open areas of Biscayne and Manatee Bays are generally low. (PDF contains 140 pages

A CRC usefulness assessment for adaptation layers in satellite systems

This paper assesses the real usefulness of CRCs in today's satellite network-to-link adaptation layers under the lights of enhanced error control and framing techniques, focusing on the DVB-S and DVB-S2 standards. Indeed, the outer block codes of their FEC schemes (Reed-Solomon and BCH, respectively) can provide very accurate error-detection information to the receiver in addition to their correction capabilities, at virtually no cost. This handy feature could be used to manage on a frame-by-frame basis what CRCs do locally, on the frames' contents, saving the bandwidth and processing load associated with them, and paving the way for enhanced transport of IP over DVB-S2. Mathematical and experimental results clearly show that if FEC has been properly congured for combined error correction and detection, having an uncorrected event after FEC decoding is likely to be an extremely improbable event. Under such conditions, it seems possible and attractive to optimize the way global error-control is done over satellite links by reducing the role of CRCs, or even by removing them from the overall encapsulation process

Charles M. Breder, Jr.: Hypothetical considerations, 1931-1937

Charles M. Breder Jr. “hypothesis” diary is a deviation from the field diaries that form part of the Breder collection housed at the Arthur Vining Davis Library, Mote Marine Laboratory. There are no notes or observations from specific scientific expeditions in the document. Instead, the contents provide an insight into the early meticulous scientific thoughts of this biologist, and how he examines and develops these ideas. It is apparent that among Dr. Breder’s passions was his continual search for knowledge about questions that still besieged many scientists. Topics discussed include symmetry, origin of the atmosphere, origin of life, mechanical analogies of organisms, aquaria as an organism, astrobiology, entropy, evolution of species, and other topics. The diary was transcribed as part of the Coastal Estuarine Data/Document Rescue and Archeology effort for South Florida. (PDF contains 33 pages

Discrete choice modelling incorporating attribute thresholds of perception

In this paper we formulate a discrete choice model that incorporates thresholds in the perception of attribute changes. The model considers multiple options and allows changes in several attributes. We postulate that if thresholds exist they could be random, differ between individuals, and even be a function of socio-economic characteristics and choice conditions. Our formulation allows estimation of the parameters of the threshold probability distribution starting from information about choices. The model is applied to synthetic data and also to real data from a stated preference survey. We found that where perception thresholds exist in the population, the use of models without them leads to errors in estimation and prediction. Clearly, the effect is more relevant when the typical size of change in the attribute value is comparable with the threshold, and when the contribution of this attribute in the utility function is substantial. Finally, we discuss the implications of the threshold model for estimation of the benefits of transport investments, and show that where thresholds exist, models that do not represent them can overestimate benefits substantially

A Theory of Corporate Capital Structure and Investment.

This article describes how financial disruptions affect investment in a general equilibrium economy. I show that in a world with differentiated lenders, the most efficient will become financial intermediaries; their preeminence will nonetheless be limited by frictions with depositors. Because of these frictions, cash rich companies prefer to tap the bond market directly, while moderately endowed firms borrow from intermediaries, and cash poor companies are unable to borrow at all. The aggregation of this model produces an economy with intuitive features: investment falls whenever the risk free rate rises, or when the financial health of firms and intermediaries deteriorates.

The Rise and Fall of Bank Control in the United States: 1890-1939

This article studies how equity ownership and corporate control were separated in the United States. Initially, railroads and industrial firms were tightly controlled by a few shareholders; this situation was altered in the 1890s by massive mergers and reorganizations, which allowed private banks to control railroads and industrial firms. Between 1912 and 1939, bank control faded away as a result of a political reaction against financial institutions. Using stock market data from 1914, I show that the eviction of banks from corporate boards depressed firm values by about 7 percent, and that part of this value came from cartelization.

Un software matemático para análisis de señales bioacústicas

El objetivo de este trabajo fue el desarrollo de una herramienta computacional que fuera una alternativa al método manual de análisis empleado tradicionalmente, permitiendo analizar y caracterizar registros sonoros de forma sistemática y objetiva, con la ventaja adicional de reducir el tiempo de procesamiento de un gran número de señales.Área: Ingeniería, Arquitectura y Tecnología

Etica generale ed etica cristiana nel pensiero di Ernst Troeltsch

In his reflections on the problems raised by the Christian ethics, Troeltsch’s starting point has always been a general theory of ethics, which should have been structured of a theoretical and of a practical part. In this sense he can be seen as a representative of the development of the modern moral thought; in particular his intention was to develop Herrman’s idea of integrating Kant’s subjective ethics with Schleiermacher’s objective ethics. This Grundkonzeption of Troeltsch’s is extremely evident when analysing his courses of lessons held at WS in 1905/06 and in 1911/12, where he indicates the concepts of moral duty or moral law, of evil (or of what is against morality), of a system of moral aims or of objective or cultural values, as the “fundamental concepts” of ethics. As for the Christian ethics, if the fact that morality and religiosity are tightly intertwined implies that “all the moral commandments of reason, which aim at the conquest of personality, are presented as emanations of God’s divine will”, then “theonomy speaks in autonomy’s name”, and the respect of the moral law is immediately recognised as a “divine obligation”. From this point of view the Christian ethics intersects the law of nature, and its story can be identified with that of the Christian natural law, interpreted and practiced from time to time “either in a more conservative, either in a more radical or democratic form”

How Do Firms Choose Their Lenders? An Empirical Investigation

This article investigates which firms borrow directly from the capital markets and which raise funds through intermediaries. Our empirical results show that large companies with abundant cash and collateral tap the credit markets directly. These markets cater to safe and profitable industries, and are most active when riskless rates or intermediary earnings are low. We show that determinants of lender selection sharpen during investment downturns and that there are substantial asymmetries in the way firms enter and exit capital markets. These results support a theoretical framework where intermediaries have better reorganizational skills but a higher cost of capital than bondholders