Ecological Sanitation: Technical Issues on the Adequacy of On-Site Storage and Treatment of Human Waste

A recent development in the water and sanitation sector is the concept of ecological sanitation (Eco-sanitation, or "Eco-San"); that is, the on-site storage and treatment of human fecal waste. The goal of this type of sanitation is to provide the user with a hygienic means of waste disposal, as well as a safe, stable, and useful end product. This paper examines the efficacy of such systems; namely, the type of treatment provided and the extent of pathogen destruction. Mathematical models of pathogen die-off data from experimental studies are used to estimate the hygienic quality of human fecal material under conditions normally found in Eco-San systems. A review of the literature shows major gaps in the data available to model the Eco-San systems. Lack of field data on the Eco-San process results in an incomplete description of the operating conditions. The scarcity of data on the kinetics of pathogen destruction at low temperatures also adds uncertainty to the assessment. Also, much of the available kinetic data is from studies that are carried out under conditions not necessarily encountered in Eco-San. Extrapolation of pathogen destruction from the kinetic models developed under different test conditions show inconsistent results. The use of the EPA Part503 Biosolids Rule pathogen reduction model also is not appropriate as a guide to determining treatment efficiency. More research and data on the survival of pathogens at lower temperature ranges is needed to determine the exact nature of Eco-San process efficiency. Existing data is used to develop a simplified model for the prediction of pathogen destruction. Recommendations are made to develop indicators of the efficacy of Eco-San treatment. The conclusions include a discussion on the way to operate double-vault latrines in dual phase manner that will result in a safe, hygienic end product.Master of Public Healt

Active symbols and internal models: Towards a cognitive connectionism

In the first section of the article, we examine some recent criticisms of the connectionist enterprise: first, that connectionist models are fundamentally behaviorist in nature (and, therefore, non-cognitive), and second that connectionist models are fundamentally associationist in nature (and, therefore, cognitively weak). We argue that, for a limited class of connectionist models (feed-forward, pattern-associator models), the first criticism is unavoidable. With respect to the second criticism, we propose that connectionist models are fundamentally associationist but that this is appropriate for building models of human cognition. However, we do accept the point that there are cognitive capacities for which any purely associative model cannot provide a satisfactory account. The implication that we draw from is this is not that associationist models and mechanisms should be scrapped, but rather that they should be enhanced.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/45877/1/146_2005_Article_BF01889764.pd

Anti-La/SSB antiidiotypic antibodies in maternal serum - A marker of low risk for neonatal lupus in an offspring

Objective. The anti-La/SSB response to major B cell epitopes of La/SSB can be blocked by an active idiotypic/antiidiotypic network, which can be identified using synthetic complementary epitopes deduced from the sequence of the major B cell epitopes of the molecule. This study evaluated the role of this network in pregnant women with anti-Ro/SSA and/or anti-La/SSB antibodies in the development of neonatal lupus syndrome (NLS). Methods. Sixty-three serum samples collected from anti-Ro/anti-La-positive women during pregnancy or within 6 months after delivery were obtained from the Research Registry for Neonatal Lupus and the PR Interval Dexamethasone Evaluation study. These samples, as well as 30 sera from healthy individuals, were tested in a blinded manner by enzyme-linked immunosorbent assay against, synthetic peptides corresponding to major B cell epitopes and complementary epitopes of La/SSB. Results. Sera from mothers giving birth to a healthy child and having no history of a child with NLS exhibited higher antiidiotypic antibody activity compared with mothers carrying a child with NLS (P < 0.0001) or mothers giving birth to a healthy child but who previously gave birth to a child with NLS (P 0.0151). Sera from mothers of healthy children, which exhibited no apparent epitope activity against amino acids 349-364, revealed a significantly greater frequency of hidden anti-349-364aa epitope responses, blocked by antiidiotypic antibodies, as compared with sera from women pregnant with an affected child (P = 0.0094). Conclusion. The presence of antiidiotypic antibodies to autoantibodies against La/SSB may protect the fetus by blocking pathogenic maternal autoantibodies. Testing for these antiidiotypic responses may be useful in predicting a decreased risk of NLS