Pluralism about Knowledge

In this paper I consider the prospects for pluralism about knowledge, that is, the view that there is a plurality of knowledge relations. After a brief overview of some views that entail a sort of pluralism about knowledge, I focus on a particular kind of knowledge pluralism I call standards pluralism. Put roughly, standards pluralism is the view that one never knows anything simpliciter. Rather, one knows by this-or-that epistemic standard. Because there is a plurality of epistemic standards, there is a plurality of knowledge relations. In §1 I argue that one can construct an impressive case for standards pluralism. In §2 I clarify the relationship between standards pluralism, epistemic contextualism and epistemic relativism. In §3 I argue that standards pluralism faces a serious objection. The gist of the objection is that standards pluralism is incompatible with plausible claims about the normative role of knowledge. In §4 I finish by sketching the form that a standards pluralist response to this objection might take

The conceptual design of a hybrid life support system based on the evaluation and comparison of terrestrial testbeds

This report summarizes a trade study of different options of a bioregenerative Life Support System (LSS) and a subsequent conceptual design of a hybrid LSS. The evaluation was based mainly on the terrestrial testbed projects MELISSA (ESA) and BIOS (Russia). In addition, some methods suggested by the Advanced Life Support Project (NASA) were considered. Computer models, including mass flows were established for each of the systems with the goal of closing system loops to the extent possible. In order to cope with the differences in the supported crew size and provided nutrition, all systems were scaled for supporting a crew of six for a 780 day Mars mission (180 days transport to Mars; 600 days surface period) as given in the NASA Design Reference Mission Scenario [Hoffman, S.J., Kaplan, D.L. Human exploration of Mars: the Reference Mission of the NASA Mars Exploratory Study, 1997]. All models were scaled to provide the same daily allowances, as of calories, to the crew. Equivalent System Mass (ESM) analysis was used to compare the investigated system models against each other. Following the comparison of the terrestrial systems, the system specific subsystem options for Food Supply, Solid Waste Processing, Water Management and Atmosphere Revitalization were evaluated in a separate trade study. The best subsystem technologies from the trade study were integrated into an overall design solution based on mass flow relationships. The optimized LSS is mainly a bioregenerative system, complemented by a few physicochemical elements, with a total ESM of 18,088 kg, which is about 4 times higher than that of a pure physico-chemical LSS, as designed in an earlier study

Transcardiopulmonary thermal dye versus single thermodilution methods for assessment of intrathoracic blood volume and extravascular lung water in major burn resuscitation.

The purpose of this study was to compare the approximated values for intrathoracic blood volume (ITBV) and extravascular lung water (EVLW) obtained from a single indicator dilution to the exact data measured by double-indicator dilution. Eighteen patients with an average TBSA of 46.3% (range, 26 to 67%) and an average abbreviated burn severity index of 8.7 (range, 7 to 11) were included into a intraindividual comparative prospective study over a 20-month period. The COLD Z-021 system (Pulsion Medical Systems, Munich, Germany) was used to obtain both the exact measurements, as well as the estimated values for ITBV and EVLW. Two hundred ninety intraindividually comparative measurements were performed during the first 4 days after the burn injury. A good correlation between both techniques was shown for ITBVI (0.77;

Transcardiopulmonary vs Pulmonary Arterial Thermodilution Methods for Hemodynamic Monitoring of Burned Patients.

The objective of this study was to validate a new method of transcardiopulmonary thermodilution for assessment of cardiac index (CI), stroke volume index (SVI), systemic vascular resistance index (SVRI) and additional parameters such as intrathoracic blood volume index and extravascular lung water index (EVLWI) by comparison with conventional pulmonary artery catheter values in a severely burned population. The pulmonary artery measurements were performed continuously with the Vigilance system, and the transcardiopulmonary thermodilution with the PiCCO(R) system. One hundred thirteen measurements with each system on up to six consecutive days were taken in 14 severely burned patients (average TBSA, 49.6%; average ABSI, 10.3), aged 21 to 61 years (mean, 42.2 years) and compared intraindividually. An excellent correlation between the two methods was shown for CI (r = 0.80) and its derived parameters SVI and SVRI in states of low to normal cardiac output. The correlation was poor for cardiac indices greater then 5.5 up to their maximum values (r = 0.46). No correlation between index of oxygenation (PaO2/FiO2) vs EVLW I was observed. There was no difference between survivors and nonsurvivors, and between patients with and without inhalation injury in EVLWI. The method of transcardiopulmonary thermodilution is suitable to assess SVI, CI and SVRI under the special pathophysiologic condition of a major burn for low to normal cardiac output states. It is less reliable when cardiac output is high. The lower cost and less invasive nature are the advantages of the system compared with use of the pulmonary artery catheter. The role of intrathoracic blood volume index and EVLWI in cardiopulmonary monitoring of severely burned patients remains to be further determined

Clinical practice of glycerol preserved allograft skin coverage.

This retrospective study examines the use and advantages/disadvantages of glycerol preserved human allograft skin in our burn care facility between February 1997 and December 1999. Three hundred and twenty patients were included into the study, 85 of whom were treated with human cadaver skin. The usage of allograft slightly increased the number of operative procedures per percent of the total body surface area burn. There were no adverse effects noted from the use of allograft. The group of patients with allograft use had a significantly larger burn size, ABSI score and length of ICU stay. Demographically the groups were comparable. The considerably easier handling and storage of glycerol preserved allograft skin make it preferable to cryopreserved allograft skin in all indications where it is used as a temporary wound closure. We recommend the usage of cryopreserved skin in cases where the integration of a dermal component as a permanent part of wound closure is desired