Motile bacteria respond to environmental cues to move to more favorable locations. The components of the chemotaxis signal transduction systems that mediate these responses are highly conserved among prokaryotes including both eubacterial and archael species. The best‐studied system is that found in Escherichia coli. Attractant and repellant chemicals are sensed through their interactions with transmembrane chemoreceptor proteins that are localized in multimeric assemblies at one or both cell poles together with a histidine protein kinase, CheA, an SH3‐like adaptor protein, CheW, (...) and a phosphoprotein phosphatase, CheZ. These multimeric protein assemblies act to control the level of phosphorylation of a response regulator, CheY, which dictates flagellar motion. Bacterial chemotaxis is one of the most‐understood signal transduction systems, and many biochemical and structural details of this system have been elucidated. This is an exciting field of study because the depth of knowledge now allows the detailed molecular mechanisms of transmembrane signaling and signal processing to be investigated. BioEssays 28:9–22, 2006. © 2005 Wiley Periodicals, Inc. (shrink)

We study the effective and proof-theoretic content of the polarized Ramsey’s theorem, a variant of Ramsey’s theorem obtained by relaxing the definition of homogeneous set. Our investigation yields a new characterization of Ramsey’s theorem in all exponents, and produces several combinatorial principles which, modulo bounding for ${\Sigma^0_2}$ formulas, lie (possibly not strictly) between Ramsey’s theorem for pairs and the stable Ramsey’s theorem for pairs.

We formulate a polarized version of Ramsey’s theorem for trees. For those exponents greater than 2, both the reverse mathematics and the computability theory associated with this theorem parallel that of its linear analog. For pairs, the situation is more complex. In particular, there are many reasonable notions of stability in the tree setting, complicating the analysis of the related results.

Electrical resistivity and ac-calorimetric measurements reveal a complex magnetic phase diagram for single crystals of the ferromagnetic Kondo-lattice compound CeAgSb2 at high pressures up to 80 kbar. The ferromagnetic order at TC = 9.6 K at ambient pressure is completely suppressed at a critical pressure PC = 35 kbar. Another magnetic transition, possibly antiferromagnetic, found above 27 kbar, attains a maximum value TN 6 K at 44 kbar and then appears to be completely suppressed by 50 kbar. Thermodynamic and transport (...) measurements in the ferromagnetic state indicate an energy gap Δ 30 K in the spin-wave excitation spectrum at ambient pressure which decreases to Δ 10 K at P = 30 kbar. No superconductivity is observed at ambient pressure above T 0.1 K, under applied pressure in the ferromagnetic state (P = 28.5 kbar), nor in the antiferromagnetic state (P = 33 − 46 kbar) above 0.3 K. © 2003 The American Physical Society. (shrink)

Focal brain metabolic effects detected by proton magnetic resonance spectroscopy (MRS) in obsessive-compulsive disorder (OCD) represent prospective indices of clinical status and guides to treatment design. Sampling bilateral pregenual anterior cingulate cortex (pACC), anterior middle cingulate cortex (aMCC), and thalamus in 40 adult patients and 16 healthy controls, we examined relationships of the neurometabolites glutamate+glutamine (Glx), creatine+phosphocreatine (Cr), and choline-compounds (Cho) with OCD diagnosis and multiple symptom types. The latter included OC core symptoms (Yale-Brown Obsessive-Compulsive Scale - YBOCS), depressive symptoms (...) (Montgomery-Åsberg Depression Rating Scale - MADRS), and general functioning (Global Assessment Scale - GAS). pACC Glx was 9.7% higher in patients than controls. Within patients, Cr and Cho correlated negatively with YBOCS and MADRS, while Cr correlated positively with the GAS. In aMCC, Cr and Cho correlated negatively with MADRS, while Cr in thalamus correlated positively with GAS. These findings present moderate support for glutamatergic and cingulocentric perspectives on OCD. Based on our prior metabolic model of OCD, we offer one possible interpretation of these group and correlational effects as consequences of a corticothalamic state of elevated glutamatergic receptor activity alongside below-normal glutamatergic transporter activity. (shrink)

This response reinforces several major themes in our target article: (a) the importance of sex-specific, within-sex variation in mating tactics; (b) the relevance of optimality thinking to understanding that variation; (c) the significance of special design for reconstructing evolutionary history; (d) the replicated findings that women's mating preferences vary across their menstrual cycle in ways revealing special design; and (e) the importance of applying market phenomena to understand the complex dynamics of mating. We also elaborate on three points: (1) Men (...) who have indicators of genetic fitness may provide more direct benefits when female demand for extra-pair and short-term sex is very low; (2) both men and women track ecological cues to make mating decisions; and (3) more research on female orgasm is needed. (shrink)

Simple mass nouns are words like ‘water’, ‘furniture’ and ‘gold’. We can form complex mass noun phrases such as ‘dirty water’, ‘leaded gold’ and ‘green grass’. I do not propose to discuss the problems in giving a characterization of the words that are mass versus those that are not. For the purposes of this paper I shall make the following decrees: (a) nothing that is not a noun or noun phrase can be mass, (b) no abstract noun phrases are considered (...) mass, (c) words like ‘thing’, ‘entity’ and ‘object’ are not mass, (d) I shall not consider such words as ‘stuff’, ‘substance or ‘matter’, (e) measures on mass nouns (like ‘gallon of gasoline’, ‘blade of grass’, etc.) are not considered, (f) plurals of count terms are not considered mass. Within these limitations, we can say generally that mass noun phrases are those phrases that ‘much’ can be prefexed to, by ‘many’ cannot be prefexed to, without an0maly.l Semantically, such phrases usually have the property of collectiveness- they are true of any sum of things of which they are true ; and of divisiveness - they are true of any part (down to a certain limit) of things of which they are true. All of this, however, is only ‘generally speaking’ - I shall mostly use only the simple examples given above and ignore the problems in giving a complete characterization of mass nouns. In the paper I want to discuss some problems involved in casting English sentences containing mass nouns into some artificial language; but in order to do this we should have some anchoring framework on which to justify or reject a given proposal. The problem of finding an adequate language can be viewed as a case of translation (from English to the artificial language), where the translation relation must meet certain requirements. I shall suggest five such requirements; others could be added. (shrink)

Different researchers use "the philosophy of automated theorem p r o v i n g " t o cover d i f f e r e n t concepts, indeed, different levels of concepts. Some w o u l d count such issues as h o w to e f f i c i e n t l y i n d e x databases as part of the philosophy of automated theorem p r o v i n g . (...) Others wonder about whether f o r m u l a s should be represented as strings or as trees or as lists, and call this part of the philosophy of automated theorem p r o v i n g . Yet others concern themselves w i t h what k i n d o f search should b e embodied i n a n y automated theorem prover, or to what degree any automated theorem prover should resemble Prolog. Still others debate whether natural deduction or semantic tableaux or resolution is " b e t t e r " , a n d c a l l t h i s a part of the p h i l o s o p h y of automated theorem p r o v i n g . Some people wonder whether automated theorem p r o v i n g should be " h u m a n oriented" or "machine o r i e n t e d " — sometimes arguing about whether the internal p r o o f methods should be " h u m a n - I i k e " or not, sometimes arguing about whether the generated proof should be output in a f o r m u n d e r s t a n d a b l e by p e o p l e , and sometimes a r g u i n g a b o u t the d e s i r a b i l i t y o f h u m a n intervention in the process of constructing a proof. There are also those w h o ask such questions as whether we s h o u l d even be concerned w i t h completeness or w i t h soundness of a system, or perhaps we should instead look at very efficient (but i n c o m p l e t e ) subsystems or look at methods of generating models w h i c h might nevertheless validate invalid arguments. A n d a l l of these have been v i e w e d as issues in the philosophy of automated theorem proving. Here, I w o u l d l i k e to step back from such i m p l e m e n t - ation issues and ask: " W h a t do we really think we are doing when we w r i t e an automated theorem prover?" My reflections are perhaps idiosyncratic, but I do think that they put the different researchers* efforts into a broader perspective, and give us some k i n d of handle on w h i c h directions we ourselves m i g h t w i s h to pursue when constructing (or extending) an automated theorem proving system. A logic is defined to be (i) a vocabulary and formation rules ( w h i c h tells us w h a t strings of symbols are w e l l - formed formulas in the logic), and ( i i ) a definition of ' p r o o f in that system ( w h i c h tells us the conditions under which an arrangement of formulas in the system constitutes a proof). Historically speaking, definitions of ' p r o o f have been given in various different manners: the most c o m m o n have been H i l b e r t - s t y l e ( a x i o m a t i c ) , Gentzen-style (consecution, or sequent), F i t c h - s t y l e (natural deduction), and Beth-style (tableaux).. (shrink)

For over forty years, Leland Ryken has championed and modeled a Christian liberal arts education. His scholarship and commitment to integrating faith with learning in the classroom have influenced thousands of students who have sat under his winsome teaching. Published in honor of Professor Ryken and presented on the occasion of his retirement from Wheaton College, this compilation carries on his legacy of applying a Christian liberal arts education to all areas of life. Five sections explore the background of a (...) Christian liberal arts education, its theological basis, habits and virtues, differing approaches, and ultimate aims. Contributors including Philip Ryken, Jeffry Davis, Duane Litfin, John Walford, Alan Jacobs, and Jim Wilhoit analyze liberal arts as they relate to the disciplines, the Christian faith, and the world. Also included are a transcript of a well-known 1984 chapel talk delivered by Leland Ryken on the student's calling and practical chapters on how to read, write, and speak well. Comprehensive in scope, this substantial volume will be a helpful guide to anyone involved in higher education, as well as to students, pastors, and leaders looking for resources on the importance of faith in learning. - Publisher. (shrink)

In an interesting experimental study, Bonini et al. (1999) present partial support for truth-gap theories of vagueness. We say this despite their claim to find theoretical and empirical reasons to dismiss gap theories and despite the fact that they favor an alternative, epistemic account, which they call ‘vagueness as ignorance’. We present yet more experimental evidence that supports gap theories, and argue for a semantic/pragmatic alternative that unifies the gappy supervaluationary approach together with its glutty relative, the subvaluationary approach.

In the case of an actual proper name such as ‘Aristotle’ opinions as to the Sinn may differ. It might, for instance, be taken to be the following: the pupil of Plato and teacher of Alexander the Great. Anybody who does this will attach another Sinn to the sentence ‘Aristotle was born in Stagira’ than will a man who takes as the Sinn of the name: the teacher of Alexander the Great who was born in Stagira. So long as the (...) Bedeutung remains the same, such variations of Sinn may be tolerated, although they are to be avoided.. (shrink)

Introduction. Murder, some may suggest, is to be defined as the intentional and uncoerced killing of the innocent; and it is true by definition that murder is wrong. Yet wars, particularly modern wars, seem to require the killing of the innocent, e.g. through anti-morale terror bombing. Therefore war must be wrong.

Jeffry H. Morrison offers readers the first comprehensive look at the political thought and career of John Witherspoon—a Scottish Presbyterian minister and one of America’s most influential and overlooked founding fathers. Witherspoon was an active member of the Continental Congress and was the only clergyman both to sign the Declaration of Independence and to ratify the federal Constitution. During his tenure as president of the College of New Jersey at Princeton, Witherspoon became a mentor to James Madison and influenced many (...) leaders and thinkers of the founding period. He was uniquely positioned at the crossroads of politics, religion, and education during the crucial first decades of the new republic. Morrison locates Witherspoon in the context of early American political thought and charts the various influences on his thinking. This impressive work of scholarship offers a broad treatment of Witherspoon’s constitutionalism, including his contributions to the mediating institutions of religion and education, and to political institutions from the colonial through the early federal periods. This book will be appreciated by anyone with an interest in American political history and thought and in the relation of religion to American politics. “I have been waiting a long time for such a book on John Witherspoon. This book is not only well-researched, but well-written. The story Morrison tells is quite wonderful.” —_Michael Novak, American Enterprise Institute for Public Policy Research_ _ _ "Dr. John Witherspoon is at once an exceptionally influential figure in Early American history, and a sadly neglected one. Professor Morrison's book fills this gap in American political history brilliantly. It is especially revealing of 18th century views on the interrationships between education, religion, and society. Morrison presents new insights into the Early American understanding of balancing faith, government, and society. It will change our conceptions of this period and provide fresh perspectives on contemporary problems. Everyone interested in the American Founding era is indebted to Morrison for this illuminating book." —_Garrett Ward Sheldon, University of Virginia's College at Wise_ "At last we have a full and learned account, as the title states, of _JOHN WITHERSPOON aND THE FOUNDING OF THE AMERICAN REPUBLIC_. Including discussion of Witherspoon's direct role in the crucial events of 1775-1790 as an advocate of Independence and friend of the Constitution, as a contributor to early American religious and political thought, and most important, as a mentor to James Madison and other Princeton revolutionairies and nation-builders, Morrison reveals Witherspoon's high standing in American religious, educational, and political history. Madison remembered Witherspoon's injunction to his students to 'Lead useful Lives;' he provided an excellent role model." —_Ralph Ketcham, Syracuse University_. (shrink)

This book focuses on the degree to which certain moral and legal doctrines are rooted in specific passions that are then institutionalised in the form of criminal law. A philosophical analysis is developed of the following questions: when, if ever, should hatred be overcome by sympathy or compassion? What are forgiveness and mercy and to what degree do they require - both conceptually and morally - the overcoming of certain passions and the motivation by other passions? If forgiveness and mercy (...) indeed are moral virtues, what role, if any, should they play in the law? (shrink)

Simpson has claimed that “ATR0 is the weakest set of axioms which permits the development of a decent theory of countable ordinals” [8]. This paper provides empirical support for Simpson's claim. In particular, Cantor's Normal Form Theorem and Sherman's Inequality for countable well-orderings are both equivalent to ATR0. The proofs of these results require a substantial development of ordinal exponentiation and a strengthening of the comparability result in [3].

The conceptual framework of an Interdisciplinary Studies (IDS) program shapes the quality, variety, and results of intellectual inquiry. While there are many viable paradigms for IDS programs, a liberal arts framework particularly enhances interdisciplinary inquiry. Specifically, a liberal arts approach emphasizes integrative thinking, conceptual synthesis, character formation, and coherence across bodies of knowledge. In harmony with the liberal arts, an IDS program equips students to productively wrestle with the inevitable dysfunction and complexity of this world. By situating the task of (...) inquiry among multiple disciplines, interdisciplinarians cultivate ethical-moral discernment alongside fluency in differing modes of academic analysis. Additionally, when oriented towards the liberal arts, an IDS program counters the false pragmatism of careerism and specialization by producing creative critical thinkers who can thrive in a variety of fields. Contextualizing interdisciplinary studies within a liberal arts schema provides students with rich opportunities to unite the mind, the passions, and the will for greater flourishing. (shrink)

We have all been victims of wrongdoing. Forgiving that wrongdoing is one of the staples of current pop psychology dogma; it is seen as a universal prescription for moral and mental health in the self-help and recovery section of bookstores. At the same time, personal vindictiveness as a rule is seen as irrational and immoral. In many ways, our thinking on these issues is deeply inconsistent; we value forgiveness yet at the same time now use victim-impact statements to argue for (...) harsher penalties for criminals. Do we have a right to hate others for what they have done to us? Providing a nuanced approach to a proper understanding of the place of our strongest emotions in moral, political, and personal life, and using lucid, easily understood prose, this volume is a classic example of philosophical thinking applied to a thorny, everyday problem. (shrink)

Natural deduction is the type of logic most familiar to current philosophers, and indeed is all that many modern philosophers know about logic. Yet natural deduction is a fairly recent innovation in logic, dating from Gentzen and Jaśkowski in 1934. This article traces the development of natural deduction from the view that these founders embraced to the widespread acceptance of the method in the 1960s. I focus especially on the different choices made by writers of elementary textbooks—the standard conduits of (...) the method to a generation of philosophers—with an eye to determining what the ‘essential characteristics’ of natural deduction are. (shrink)

Based on a series of lectures delivered at the University of Virginia in October 1981. Includes bibliographical references and index.

Scientists employ a variety of procedures to eliminate degrees of freedom from computationally and/or analytically intractable equations. In the process, they often construct new models and discover new concepts, laws and functional relations. I argue these procedures embody a central notion of reduction, namely, the containment of one structure within another. However, their inclusion in the philosophical concept of reduction necessitates a reevaluation of many standard assumptions about the ontological, epistemological and functional features of a reduction. On the basis of (...) the reevaluation, I advocate a continuum of reduction which proceeds from the eliminative to the constructive. The metaphysical aspects of theory use in constructive reductions are sketched. (shrink)

Chemists take mechanisms to be an important way of explaining chemical change. I examine the usefulness of the mechanism approach in the recent philosophical literature in explicating the explanatory use of mechanisms by organic chemists. I argue that chemists consider a mechanism to be explanatory because it accounts for the “dynamic process of bringing about” (Tabery 2004 , 10) chemical change. For chemists, mechanisms are causal explanations based on interventions that show “how some possibilities depend on others” (Woodward 2003 , (...) 375). Only possibilities are achievable because chemists face a number of challenges when they explain by means of a mechanism. †To contact the author, please write to: Department of Philosophy, Smith College, Northampton, MA 01063; e‐mail: [email protected]. (shrink)

We show that when certain statements are provable in subsystems of constructive analysis using intuitionistic predicate calculus, related sequential statements are provable in weak classical subsystems. In particular, if a $\Pi^1_2$ sentence of a certain form is provable using E-HA ${}^\omega$ along with the axiom of choice and an independence of premise principle, the sequential form of the statement is provable in the classical system RCA. We obtain this and similar results using applications of modified realizability and the Dialectica interpretation. (...) These results allow us to use techniques of classical reverse mathematics to demonstrate the unprovability of several mathematical principles in subsystems of constructive analysis. (shrink)

By stressing the act rather than the relation of approximation, I argue that the magnitude of the error introduced should not be used as the sole criterion for judging the worth of the approximation. Magnitude is a necessary but not sufficient condition for such a judgement. Controllability, the absence of cancelling errors, and the approximation's justification are also important criteria to consider when praising or blaming an approximation. Boltzmann's discussion of the types of approximations used in the kinetic theory of (...) gases at the turn of the century illustrates the use of these criteria. (shrink)

Prediction is more than testing established theory by examining whether the prediction matches the data. To show this, I examine the practices of a community of scientists, known as threaders, who are attempting to predict the final, folded structure of a protein from its primary structure, i.e., its amino acid sequence. These scientists employ a careful and deliberate methodology of prediction. A key feature of the methodology is calibration. They calibrate in order to construct better models. The construction leads to (...) knowledge of how to construct or build an object. Thus, prediction serves a cognitive goal of model construction and not just model or theory testing. The kind of knowledge that results is relevantly different than theoretical knowledge. (shrink)

In this commentary, we attempt to broaden thinking and dialogue about how our ancestral past might have affected attachment and reproductive strategies. We highlight the theoretical benefits of formulating specific predictions of how different sources of stress might impact attachment and reproductive strategies differently, and we integrate some of these ideas with another recent evolutionary model of human mating.

Two studies examined the link between social dominance and male waist-to-hip ratio (WHR). Groups of four men interacted in a leaderless group discussion. In both studies, men with higher WHRs (associated with current and long-term health status) were rated by other group members as behaving more leader-like when an observer was present, and rated themselves as being more assertive. In Study 2, men with higher WHRs were rated by independent observers as behaving more dominantly, but only when the evaluator was (...) present. These results are discussed in terms of evolutionary models of health, attraction, and intrasexual competition. (shrink)

We show that \\) cannot be proved with one typical application of \\) in an intuitionistic extension of \ to higher types, but that this does not remain true when the law of the excluded middle is added. The argument uses Kohlenbach’s axiomatization of higher order reverse mathematics, results related to modified reducibility, and a formalization of Weihrauch reducibility.

Philosophers disagree how abstract, theoretical principles can be applied to instances. This paper generates a puzzle for law theorists, causal theorists and inductivists alike. Intractability can force scientists to use a "semi-empirical" method, in which some of an equation's theoretically-determinable parameters are replaced with values taken directly from the data. This is not a purely deductive or inductive process, nor does it involve causes and capacities in any simple way (Humphreys 1995). I argue the predictive successes of such methods require (...) us to reanalyze our views about the nature of prediction, the status of models, and the goal(s) of science. When laws and experimental evidence are neither individually nor jointly sufficient for prediction, models become the locus of understanding. I analyze an historically important debate about the use of semi-empirical methods to construct potential energy surfaces. (shrink)