The Eroding Artificial/Natural Distinction: Some Consequences for Ecology and Economics

Since Thomas Kuhn’s The Structure of Scientific Revolutions (1962), historians and philosophers of science have paid increasing attention to the implications of disciplinarity. In this chapter we consider restrictions posed to interdisciplinary exchange between ecology and economics that result from a particular kind of commitment to the ideal of disciplinary purity, that is, that each discipline is defined by an appropriate, unique set of objects, methods, theories, and aims. We argue that, when it comes to the objects of study in ecology and economics, ideas of disciplinary purity have been underwritten by the artificial-natural distinction. We then problematize this distinction, and thus disciplinary purity, both conceptually and empirically. Conceptually, the distinction is no longer tenable. Empirically, recent interdisciplinary research has shown the epistemological and policy-oriented benefits of dealing with models which explicitly link anthropogenic (i.e., “artificial”) and non-anthropogenic factors (i.e., “natural”). We conclude that, in the current age of the Anthropocene, it is to be expected that without interdisciplinary exchange, ecology and economics may relinquish global relevance because the distinct and separate systems to which each “pure” science was originally made to apply will only diminish over time

Merlin Phosphorylation by p21-activated Kinase 2 and Effects of Phosphorylation on Merlin Localization

The Nf2 tumor suppressor gene product merlin is related to the membrane-cytoskeleton linker proteins of the band 4.1 superfamily, including ezrin, radixin, and moesin (ERMs). Merlin is regulated by phosphorylation in a Rac/cdc42-dependent fashion. We report that the phosphorylation of merlin at serine 518 is induced by the p21-activated kinase PAK2. This is demonstrated by biochemical fractionation, use of active and dominant-negative mutants of PAK2, and immunodepletion. By using wild-type and mutated forms of merlin and phospho-directed antibodies, we show that phosphorylation of merlin at serine 518 leads to dramatic protein relocalization. Neurofibromatosis type 2 (NF2)1 is an inherited disorder characterized by the development of Schwann cell tumors of the eighth cranial nerve. Mutations and loss of heterozygosity of theNF2 gene have been detected in NF2 patients and in various sporadic tumors, including schwannomas, meningiomas, and ependymomas (1). In further support of a role for NF2 in tumor suppression, mice heterozygous for an Nf2 mutation are predisposed to a wide variety of tumors with high metastatic potential (2). In a separate model in which Nf2 is inactivated specifically in Schwann cells, mice develop schwannomas and Schwann cell hyperplasia (3). The longest and predominant splice form of the Nf2gene codes for a 595-amino acid protein highly similar to the band 4.1 family of proteins. It is most closely related to the ERM proteins,moesin, ezrin, and radixin. The ERM proteins are thought to function as cell membrane-cytoskeleton linkers and are localized to cortical actin structures near the plasma membrane such as microvilli, membrane ruffles, and lamellipodia (4, 5). Likewise, merlin is localized to cortical actin structures, in patterns that partially overlap with the ERMs (1). It has been proposed that intramolecular binding of the N-terminal and C-terminal domains conformationally regulates the ERM proteins by masking binding sites for interacting proteins. The ERMs can also form homodimers and heterodimers, among themselves and with merlin, adding an additional level of complexity to the regulation of these proteins (6). The recently solved crystal structure of the moesin N/C-terminal complex strengthens this model of conformational regulation (7). Given the sequence and, most likely, structural similarities of merlin to the ERM proteins, it is possible that merlin itself could be regulated in a similar fashion. Recent studies (8, 9) have implicated additional factors in the regulation of the ERMs, including phospholipids and phosphorylation. Previous work from our group and others (10, 11) has shown that merlin is differentially phosphorylated as well and that merlin protein levels are affected by growth conditions such as cell confluency, loss of adhesion, or serum deprivation. Merlin is found in an hypophosphorylated form when the combination of cellular and environmental conditions are growth-inhibitory (10). ERMs can be phosphorylated by Rho kinase, and this phosphorylation can affect intramolecular association and cellular localization. Phosphorylation and/or phospholipids may promote the transition of the proteins to an active form by “opening” intra- and intermolecular associations. These active monomers can then bind to other interacting proteins and the actin cytoskeleton and induce actin-rich membrane projections (5,8, 12, 13). The induction of merlin phosphorylation by activated alleles of the Rho family GTPases has also been examined. Interestingly, although activated Rho did not induce noticeable phosphorylation of merlin, activated forms of Rac and cdc42 did. The site of Rac-induced phosphorylation was determined to be a serine at position 518; mutation of serine 518 results in reduced basal phosphorylation and eliminated Rac-induced phosphorylation (11). Although Rac and cdc42 are implicated in the regulation of many pathways, they are most associated with regulation of cytoskeleton reorganization and gene expression (for recent reviews see Refs.14-16). In light of the data demonstrating that activated Rac/cdc42 leads to phosphorylation and possible inactivation of merlin, the elucidation of the responsible effector pathways and their effects on merlin function are of major importance. Understanding this regulation of merlin could lead to a more complete appreciation of the effects of merlin loss in tumors

Independent components in stimulus-related BOLD signals and estimation of the underlying neural responses

We measured blood oxygen level dependent (BOLD) responses to the onset of dynamic noise stimulation in defined regions of the primary retinotopic projection (V1) in visual cortex. The response waveforms showed a remarkable diversity across stimulus types, violating the basic assumption of a unitary general linear model of a uniform BOLD response function convolved with each stimulus sequence. We used independent component analysis (ICA) to analyze the component mechanisms contributing to these responses. The underlying neural responses for the components were estimated by nonlinear optimization through the Friston–Buxton hemodynamic model of the BOLD response. Our analysis suggests that one of the identified components reflected a sustained neural response to the stimulus and that another reflected an extremely slow neural response. A third component exhibited nonlinear change-specific transient responses. The first two components showed stable spatial structure in the V1 region of interest with respect to the eccentricity of the noise stimulus

Estimating the Economic Value of Specific Characteristics Associated with Angus Bulls Sold at Auction

The genetic traits of a purebred bull convey the reproductive and economic value to buyers. This study examines and compares the value of actual production weights (birth, weaning, and yearling weight), production expected progeny differences (EPDs) (birth, weaning, milk, and yearling), and ultrasound EPDs (carcass quality predictors) for purebred Angus bulls sold at auction. One EPD, birth weight, was valued by buyers more than its corresponding actual weight, though both actual weights and EPDs significantly impact price. Predictors of carcass quality were important in determining price. Finally, several individual animal factors and sale characteristics were significant in determining price.Angus bulls, carcass characteristics, EPDs, marketing factors, production factors, Agribusiness, Agricultural and Food Policy, Agricultural Finance, Food Consumption/Nutrition/Food Safety, Livestock Production/Industries, Q10, Q12,

ESTIMATING THE ECONOMIC VALUES ASSOCIATED WITH EPDS FOR ANGUS BULLS AT AUCTION

The genetic traits that an Angus bull possesses convey the reproductive and economic value of the animal to potential buyers. This paper examines and draws comparisons between the value of actual production weights and production EPDs, while also establishing values for ultrasound EPDs. Results indicate that only one EPD, birth weight, was valued by buyers more than its corresponding actual weight, though actual weights and EPDs significantly impacted price. Ultrasound EPDs were also found to be significant, suggesting buyers of Angus bulls consider carcass information when purchasing bulls.Angus Bulls, Birth Weight, Carcass, EPDs, Hedonic Model, Livestock Production/Industries,

Genome-Wide Transposon Screen of a Pseudomonas syringae mexB Mutant Reveals the Substrates of Efflux Transporters.

Bacteria express numerous efflux transporters that confer resistance to diverse toxicants present in their environment. Due to a high level of functional redundancy of these transporters, it is difficult to identify those that are of most importance in conferring resistance to specific compounds. The resistance-nodulation-division (RND) protein family is one such example of redundant transporters that are widespread among Gram-negative bacteria. Within this family, the MexAB-OprM protein complex is highly expressed and conserved among Pseudomonas species. We exposed barcoded transposon mutant libraries in isogenic wild-type and ΔmexB backgrounds in P. syringae B728a to diverse toxic compounds in vitro to identify mutants with increased susceptibility to these compounds. Mutants with mutations in genes encoding both known and novel redundant transporters but with partially overlapping substrate specificities were observed in a ΔmexB background. Psyr_0228, an uncharacterized member of the major facilitator superfamily of transporters, preferentially contributes to tolerance of acridine orange and acriflavine. Another transporter located in the inner membrane, Psyr_0541, contributes to tolerance of acriflavine and berberine. The presence of multiple redundant, genomically encoded efflux transporters appears to enable bacterial strains to tolerate a diversity of environmental toxins. This genome-wide screen performed in a hypersusceptible mutant strain revealed numerous transporters that would otherwise be dispensable under these conditions. Bacterial strains such as P. syringae that likely encounter diverse toxins in their environment, such as in association with many different plant species, probably benefit from possessing multiple redundant transporters that enable versatility with respect to toleration of novel toxicants.IMPORTANCE Bacteria use protein pumps to remove toxic compounds from the cell interior, enabling survival in diverse environments. These protein pumps can be highly redundant, making their targeted examination difficult. In this study, we exposed mutant populations of Pseudomonas syringae to diverse toxicants to identify pumps that contributed to survival in those conditions. In parallel, we examined pump redundancy by testing mutants of a population lacking the primary efflux transporter responsible for toxin tolerance. We identified partial substrate overlap for redundant transporters, as well as several pumps that appeared more substrate specific. For bacteria that are found in diverse environments, having multiple, partially redundant efflux pumps likely allows flexibility in habitat colonization

Observations of Global and Local Infall in NGC 1333

We report ``infall asymmetry'' in the HCO$^+$ (1--0) and (3--2) lines toward NGC 1333, extended over $\sim 0.39 {\rm pc}^2$, a larger extent than has been reported be fore, for any star-forming region. The infall asymmetry extends over a major portion of the star-forming complex, and is not limited to a single protostar, or to a single dense core, or to a single spectral line. It seems likely that the infall asymmetry represents inward motions, and that these motions are physically associated with the complex. Both blue-asymmetric and red-asymmetric lines are seen, but in both the (3--2) and (1--0) lines of HCO$^+$ the vast majority of the asymmetric lines are blue, indicating inward motions. The (3--2) line, tracing denser gas, has the spectra with the strongest asymmetry and these spectra are associated with the protostars IRAS 4A and 4B, which most likely indicates a warm central source is affecting the line profiles. The (3--2) and (1--0) lines usually have the same sense of asymmetry in common positions, but their profiles differ significantly, and the (1--0) line appears to trace motions on much larger spatial scales than does the (3--2) line. Line profile models fit the spectra well, but do not strongly constrain their parameters. The mass accretion rate of the inward motions is of order 10$^{-4}$ M$_\odot$/yr, similar to the ratio of stellar mass to cluster age.Comment: 28 pages, 11 figures, 1 colour figur

The Spitzer c2d Survey of Nearby Dense Cores. IX. Discovery of a Very Low Luminosity Object Driving a Molecular Outflow in the Dense Core L673-7

We present new infrared, submillimeter, and millimeter observations of the dense core L673-7 and report the discovery of a low-luminosity, embedded Class 0 protostar driving a molecular outflow. L673-7 is seen in absorption against the mid-infrared background in 5.8, 8, and 24 micron Spitzer images, allowing for a derivation of the column density profile and total enclosed mass of L673-7, independent of dust temperature assumptions. Estimates of the core mass from these absorption profiles range from 0.2-4.5 solar masses. Millimeter continuum emission indicates a mass of about 2 solar masses, both from a direct calculation assuming isothermal dust and from dust radiative transfer models constrained by the millimeter observations. We use dust radiative transfer models to constrain the internal luminosity of L673-7, defined to be the luminosity of the central source and excluding the luminosity from external heating, to be 0.01-0.045 solar luminosities, with 0.04 solar luminosities the most likely value. L673-7 is thus classified as a very low luminosity object (VeLLO), and is among the lowest luminosity VeLLOs yet studied. We calculate the kinematic and dynamic properties of the molecular outflow in the standard manner, and we show that the expected accretion luminosity based on these outflow properties is greater than or equal to 0.36 solar luminosities. The discrepancy between this expected accretion luminosity and the internal luminosity derived from dust radiative transfer models indicates that the current accretion rate is much lower than the average rate over the lifetime of the outflow. Although the protostar embedded within L673-7 is consistent with currently being substellar, it is unlikely to remain as such given the substantial mass reservoir remaining in the core.Comment: 19 pages, 14 figures. Accepted by Ap

The New Zealand Strong Motion Earthquake Recorder Network

The network of strong-motion earthquake recorders, maintained throughout New Zealand by the Engineering Seismology Section of the Department of Scientific and Industrial Research, is described. The instruments are either deployed as ground instruments to measure potential earthquake attack on structures, or in structures, e.g. buildings, dams and industrial installations, to record structural response. Details are given of installation of instruments , maintenance, laboratory work, record retrieval and digitisation, costs and staffing for the network. Future developments mooted include an improved digitising system, the introduction of an improved version of the existing mechanical-optical instrument in 1979, and, in the long term, the introduction of an entirely new digital recorder, having an electrical output from its accelerometers, which will make possible the transmission of data by telephone or radio link