Two puzzles for Marquis's conservative view on abortion

Don Marquis argues that abortion is morally wrong in most cases since it deprives the fetus of the value of its future. I criticize Marquis’s argument for the modified conservative view by adopting an argumentative strategy in which I work within his basic account: if it is granted that his fundamental idea is sound, what follows about the morality of abortion? I conclude that Marquis is faced with a dilemma: either his position must shift towards the extreme conservative view on which abortion is never morally permissible, or he must abandon any recognizably conservative view. This dilemma suggests that Marquis’s view is either deeply implausible or that he cannot use this argument to successfully support his preferred position.     

Stem cell research in Asia: A critical view

Stem cell research stands as a high‐priority field in many countries across the Asia‐Pacific region, and the past decade has seen remarkable investment into facilities and programs intended to increase competitiveness in the drive to find clinical applications. In the years roughly framed by Korean cloner Woo‐Suk Hwang's meteoric ascent and fall, speculation was rampant that Asia was poised to overtake the West in this field of science. But that potential remains unfulfilled. In this article, I will look at some of the deficits in infrastructure and governance that underlie the East–West stem cell gap, and suggest a number of measures that might be taken to remedy them. J. Cell. Biochem. 107: 853–856, 2009. © 2009 Wiley‐Liss, Inc.     

Hempel's view on functional explanation some critical comments

Summary Functional explanations are regarded as a special type of explanation by many biologists. Philosophers of science tend to agree that they are weak forms of the common modes of explanation, although the elucidation of the logical structure involved is difficult. The present paper shows that Hempel's reconstruction of functional explanations is inadequate on pragmatic grounds. Thus his conclusion that such explanations are necessarily weak is also objectionable. There is no reason for allotting functional explanations a special logical status.     

Tumor initiating cells in pancreatic cancer: A critical view

Emerging evidence points to the existence of pancreatic cancer stem cells (CSC) as the culprit in the initiation, maintenance, metastasis, and treatment resistance of pancreatic cancer. The existence of such a cell population would have an important impact on the design of novel therapies against this devastating disease. However, no in vivo validation or rebuttal of the pancreatic CSC hypothesis exists. Major backlashes in the discussion on CSC are firstly, the confusion between the terms CSC and cell of origin of pancreatic ductal adenocarcinoma (PDAC), secondly the ambiguity of the cell of origin itself and thirdly, the fact that the CSC hypothesis is based on cell sorting and xenografting experiments; the latter of which often precludes solid conclusions because of the lack of a natural microenvironment and differences in drug delivery. Nonetheless, recent studies in other cancers partially support the CSC hypothesis by demonstrating a link between epithelial-to-mesenchymal transdifferentiation/transition (EMT) and CSC properties. Such a link is again open to dispute as EMT is a reversible process which is highly dependent on major oncogenic pathways in PDAC [e.g. K-Ras, transforming growth factor-β (TGF-β)] rather than on presumed cancer stem cell pathways. Hence, the available evidence does not robustly support the CSC concept in PDAC and a thorough validation of this hypothesis in well-defined genetically engineered mouse models of pancreatic cancer is required.     

Mitochondrial introns: a critical view

Although group I and group II introns were discovered more than 25 years ago, they are still difficult to identify. Modeling their RNA structure also remains particularly challenging for organelle sequences, owing to their great diversity. In fact, accelerated evolution in organelles often results in a reduced RNA structure and a loss of autocatalytic splicing and intron mobility. We set out to identify all mitochondrial group I and II introns in published sequences, and, to this end, we developed and applied a new search approach: RNAweasel. On the basis of the results, we focus here on building a comprehensive picture of mitochondrial group I introns, including a modified (reduced) consensus RNA secondary structure and a concise phylogeny-based subclassification.     

Pandanus tectorius Parkins, in Australia: a conservative view

Pandanus tectorius Parkins, is a widespread and variable species with many forms, often local, some of which have been considered as distinct species. Fourteen binomials are here considered as synonyms of P. tectorius, but several of them warrant retention at varietal rank. Comments on the variability and its relation to a species concept in the genus Pandanus are included.     

Effect of hydrazine deproteination on bone mineral phase: a critical view

Over the last 30 years several techniques have been developed to separate bone matrix and bone mineral, in order to allow for a study of each component independently of the other. Preservation of original characteristics of the phase studied after isolation has always been a great challenge for all such techniques. The hydrazine deproteination procedure, first proposed by Termine, has been one of the processes most widely used for studying bone mineral. It is found to be one of the most effective, notwithstanding controversy over its efficiency in bone deproteination and criticism regarding possible changes it could make to the characteristics of bone mineral. In this work, we have studied the possible chemical and physical alterations caused by the hydrazine deproteination process to bone mineral from rats and to other materials of biological interest. Materials were characterized by scanning electron microscopy (SEM), thermogravimetric analysis (TGA), X-ray diffractometry (XRD), inductive coupled plasma-optical emission spectroscopy (ICP-OES), C-H-N analysis and infrared spectroscopy (FTIR), before and after hydrazine deproteination. Finally, here we present a comprehensive discussion on the criticism of hydrazine deproteination. The experimental results obtained in this work, even when compared to the results in the literature, show that most widespread criticism to the hydrazine deproteination process is not completely justified.     

A critical analysis of the view that right atrial pressure determines venous return.

A. C. Guyton pioneered major advances in understanding cardiovascular equilibrium. He superimposed venous return curves on cardiac output curves to reveal their intersection at the one level of right atrial pressure (Pra) and flow simultaneously consistent with independent properties of the heart and vasculature. He showed how this point would change with altered properties of the heart (e.g., contractility, sensitivity to preload) and/or of the vasculature (e.g., resistance, total volume). In such graphical representations of negative feedback between two subdivisions of a system, one input/output relationship is necessarily plotted backward, i.e., with the input variable on the y-axis (here, the venous return curve). Unfortunately, this format encourages mistaken ideas about the role of Pra as a "back pressure," such as the assertion that elevating Pra to the level of mean systemic pressure would stop venous return. These concepts are reexamined through review of the original experiments on venous return, presentation of a hypothetical alternative way for obtaining the same data, and analysis of a simple model.     

A view on microbial ecology

World Journal of Microbiology and Biotechnology - In the research areas referred to above the Department of General Microbiology in Copenhagen is involved directly or indirectly. Microbial ecology...     

A remark on the distribution of conservative quantities

In line with a suggestion made in the recent book by the author, a distribution function is derived for the distribution in a social group of such conservative quantities for which every individual has a minimum requirement, this minimum requirement varying from individual to individual.     

A critical view on social performance assessment at company level: social life cycle analysis of an algae case

The International Journal of Life Cycle Assessment - Social indicators are not easy to be quantitatively analyzed, although at the local scale, the social impacts might be relevant and important....     

A conservative test of genetic drift in the endosymbiotic bacterium Buchnera: slightly deleterious mutations in the chaperonin groEL

The obligate endosymbiotic bacterium Buchnera aphidicola shows elevated rates of sequence evolution compared to free-living relatives, particularly at nonsynonymous sites. Because Buchnera experiences population bottlenecks during transmission to the offspring of its aphid host, it is hypothesized that genetic drift and the accumulation of slightly deleterious mutations can explain this rate increase. Recent studies of intraspecific variation in Buchnera reveal patterns consistent with this hypothesis. In this study, we examine inter- and intraspecific nucleotide variation in groEL, a highly conserved chaperonin gene that is constitutively overexpressed in Buchnera. Maximum-likelihood estimates of nonsynonymous substitution rates across Buchnera species are strikingly low at groEL compared to other loci. Despite this evidence for strong purifying selection on groEL, our intraspecific analysis of this gene documents reduced synonymous polymorphism, elevated nonsynonymous polymorphism, and an excess of rare alleles relative to the neutral expectation, as found in recent studies of other Buchnera loci. Comparisons with Escherichia coli generally show patterns predicted by their differences in N(e). The sum of these observations is not expected under relaxed or balancing selection, selective sweeps, or increased mutation rate. Rather, they further support the hypothesis that drift is an important force driving accelerated protein evolution in this obligate mutualist.