Ideal Hypothesis Research Articles

Denoising of Hyperspectral Images Employing Two-Phase Matrix Decomposition

Noise reduction is a significant preprocessing step for hyperspectral image (HSI) analysis. There are various noise sources, leading to the difficulty in developing a somewhat universal technique for noise reduction. A majority of the existing denoising strategies are designed to tackle a certain kind of noise, with somewhat idealized hypotheses imposed on them. Therefore, it is desirable to develop a noise reduction technique with high universality for various noise patterns. Matrix decomposition can decompose a given matrix into two components if they have low-rank and sparse properties. This fits the case of HSI denoising when an HSI is reorganized as a matrix, because the noise-free signal of HSI has low rank due to the high correlations within its content, while the noise of HSI has structured sparsity with respect to the big volume of data. Moreover, matrix decomposition avoids denoising process falling into the dependence on distribution characteristics of the noise or making some idealized assumptions on HSI signal and noise. In this paper, a two-phase matrix decomposition scheme is presented. First, by employing the low-rank property of HSI signal and the structured sparsity of HSI noise, the hyperspectral data matrix is decomposed into a basic signal component and a rough noise component. Then, the latter is further decomposed into a spatial compensation part and a final noise part, via using the band-by-band total variation (TV) regularization. A number of simulated and real data experiments demonstrate that the proposed approach produces superior denoising results for different HSI noise patterns within a wide range of noise levels.

FUNDAMENTAL LIMITATIONS OF HIGH CONTRAST IMAGING SET BY SMALL SAMPLE STATISTICS

In this paper, we review the impact of small sample statistics on detection thresholds and corresponding confidence levels (CLs) in high contrast imaging at small angles. When looking close to the star, the number of resolution elements decreases rapidly towards small angles. This reduction of the number of degrees of freedom dramatically affects CLs and false alarm probabilities. Naively using the same ideal hypothesis and methods as for larger separations, which are well understood and commonly assume Gaussian noise, can yield up to one order of magnitude error in contrast estimations at fixed CL. The statistical penalty exponentially increases towards very small inner working angles. Even at 5-10 resolution elements from the star, false alarm probabilities can be significantly higher than expected. Here we present a rigorous statistical analysis which ensures robustness of the CL, but also imposes a substantial limitation on corresponding achievable detection limits (thus contrast) at small angles. This unavoidable fundamental statistical effect has a significant impact on current coronagraphic and future high contrast imagers. Finally, the paper concludes with practical recommendations to account for small number statistics when computing the sensitivity to companions at small angles and when exploiting the results of direct imaging planet surveys.

Reid's response to Hume's perceptual relativity argument

Reid declared Hume's appeal to variation in the magnitude of a table with distance to be the best argument that had ever been offered for the ‘ideal hypothesis’ that we experience nothing but our own mental states. Reid's principal objection to this argument fails to apply to minimally visible points. He did establish that we have reason to take our perceptions to be caused by external objects. But his case that we directly perceive external objects is undermined by what Hume had to say about the role played by color in our perception of the primary qualities of bodies.

Equivalence of chain conformations in the surface region of a polymer melt and a single Gaussian chain under critical conditions

In the melt polymer conformations are nearly ideal according to Flory's ideality hypothesis. Silberberg generalized this statement for chains in the interfacial region. We check the Silberberg argument by analyzing the conformations of a probe chain end-grafted at a solid surface in a sea of floating free chains of concentration φ by the self-consistent field (SCF) method. Apart from the grafting, probe chain and floating chains are identical. Most of the results were obtained for a standard SCF model with freely jointed chains on a six-choice lattice, where immediate step reversals are allowed. A few data were generated for a five-choice lattice, where such step reversals are forbidden. These coarse-grained models describe the equilibrium properties of flexible atactic polymer chains at the scale of the segment length. The concentration was varied over the whole range from φ = 0 (single grafted chain) to φ = 1 (probe chain in the melt). The number of contacts with the surface, average height of the free end and its dispersion, average loop and train length, tail size distribution, end-point and overall segment distributions were calculated for a grafted probe chain as a function of φ, for several chain lengths and substrate∕polymer interactions, which were varied from strong repulsion to strong adsorption. The computations show that the conformations of the probe chain in the melt do not depend on substrate∕polymer interactions and are very similar to the conformations of a single end-grafted chain under critical conditions, and can thus be described analytically. When the substrate∕polymer interaction is fixed at the value corresponding to critical conditions, all equilibrium properties of a probe chain are independent of φ, over the whole range from a dilute solution to the melt. We believe that the conformations of all flexible chains in the surface region of the melt are close to those of an appropriate single chain in critical conditions, provided that one end of the single chain is fixed at the same point as a chain in the melt.

Preheated shock experiments in the molten CaAl2Si2O8‐CaFeSi2O6‐CaMgSi2O6 ternary: A test for linear mixing of liquid volumes at high pressure and temperature

AbstractWe performed 17 new shock wave experiments on preheated (1673 K) hedenbergite liquid (CaFeSi2O6) and two model basalt liquids (an equimolar binary mix of CaAl2Si2O8 + CaFeSi2O6 and an equimolar ternary mix of CaAl2Si2O8 + CaFeSi2O6 +CaMgSi2O6) in order to determine their equations of state (EOS). Ambient pressure density measurements on these and other Fe‐bearing silicate liquids indicate that FeO has a partial molar volume that is highly dependent on composition, which leads to large errors in estimates of the densities of Fe‐bearing liquids at ambient pressure based on an ideal mixing of any fixed set of end‐member liquids. We formulated a series of mixing tests using the EOS determined in this study to examine whether ideal mixing of volumes might nevertheless suffice to describe the ternary system CaAl2Si2O8‐CaFeSi2O6‐CaMgSi2O6 at high temperature and pressure. The ideal mixing null hypothesis is rejected; compositional variations in partial molar volume of FeO appear to extend to high pressure. Only densities of Fe‐bearing liquid mixtures with oxide mole fraction of FeO less than 0.06 can be adequately approximated using an ideal solution.

How Recent History Affects Perception: The Normative Approach and Its Heuristic Approximation

There is accumulating evidence that prior knowledge about expectations plays an important role in perception. The Bayesian framework is the standard computational approach to explain how prior knowledge about the distribution of expected stimuli is incorporated with noisy observations in order to improve performance. However, it is unclear what information about the prior distribution is acquired by the perceptual system over short periods of time and how this information is utilized in the process of perceptual decision making. Here we address this question using a simple two-tone discrimination task. We find that the “contraction bias”, in which small magnitudes are overestimated and large magnitudes are underestimated, dominates the pattern of responses of human participants. This contraction bias is consistent with the Bayesian hypothesis in which the true prior information is available to the decision-maker. However, a trial-by-trial analysis of the pattern of responses reveals that the contribution of most recent trials to performance is overweighted compared with the predictions of a standard Bayesian model. Moreover, we study participants' performance in a-typical distributions of stimuli and demonstrate substantial deviations from the ideal Bayesian detector, suggesting that the brain utilizes a heuristic approximation of the Bayesian inference. We propose a biologically plausible model, in which decision in the two-tone discrimination task is based on a comparison between the second tone and an exponentially-decaying average of the first tone and past tones. We show that this model accounts for both the contraction bias and the deviations from the ideal Bayesian detector hypothesis. These findings demonstrate the power of Bayesian-like heuristics in the brain, as well as their limitations in their failure to fully adapt to novel environments.

A Dialectical Approach to Rethinking Roommate Relationships

Previous research on the complex interplay between roommate factors and relational satisfaction has offered contradictory findings. This study establishes a typology that accounts for relational satisfaction among first-year college roommates. Drawing from the theoretical framework of Interactional Dialectics and the ideal hypothesis, three roommate types were proposed and analyzed. The results suggest that individuals who share the same roommate type report higher levels of relational satisfaction. Furthermore, this study found that smaller discrepancies between individuals' ideal and actual roommate relationships yielded higher levels of relational satisfaction. Implications and directions for future research on roommate relationships are discussed.

Testing the Ideal Free Distribution Hypothesis: Moose Response to Changes in Habitat Amount

According to the ideal free distribution hypothesis, the density of organisms is expected to remain constant across a range of habitat availability, provided that organisms are ideal, selecting habitat patches that maximize resource access, and free, implying no constraints associated with patch choice. The influence of the amount of habitat on moose (Alces alces) pellet group density as an index of moose occurrence was assessed within the Foothills Natural Region, Alberta, Canada, using a binary patch-matrix approach. Fecal pellet density was compared across 45 sites representing a gradient in habitat amount. Pellet density in moose habitat increased in a linear or quadratic relationship with mean moose habitat patch size. Moose pellet density decreased faster thanwhatwould be expected from a decrease in habitat amount alone. This change in pellet group density with habitat amount may be because one or both of the assumptions of the ideal free distribution hypothesis were violated.

A Simple Explicit Equation for the Saturation Temperature of Humid Air

AbstractBased on the Clausius‐Clapeyron equation and the ideal gas hypothesis for the gas phase, an explicit equation is derived for the saturation temperature of humid air. In order to account for the real gas effects in the vapor phase, the expression is then modified by using the state equation of a pure water two‐phase (vapor‐liquid) system at equilibrium recommended by Wagner and Pruss. Unlike other equations, it does not require knowledge of the relative humidity. The new equation describes the saturation temperature of humid air as a function of humidity ratio x and system pressure p in the following ranges: 0 < x < 0.2; 0.5 bar < p < 16 bar. As a side product, a simple expression for relative humidity is deduced.

Non-extensivity of the chemical potential of polymer melts

Following Flory's ideality hypothesis, the chemical potential of a test chain of length n immersed into a dense solution of chemically identical polymers of length distribution P(N) is extensive in n . We argue that an additional contribution deltamu(c)(n) approximately +1/rho (sqrt[n]) arises (rho being the monomer density) for all P(N) if n " <N> which can be traced back to the overall incompressibility of the solution leading to a long-range repulsion between monomers. Focusing on Flory-distributed melts, we obtain deltamu(c)(n) approximately equal to (1 - 2n/ <N> ) / rho (sqrt[n]) for n " <N>(2) , hence, deltarho(c)(n) approximately equal to -1/rho (sqrt[n]) if n is similar to the typical length of the bath <N> . Similar results are obtained for monodisperse solutions. Our perturbation calculations are checked numerically by analyzing the annealed length distribution P(N) of linear equilibrium polymers generated by Monte Carlo simulation of the bond fluctuation model. As predicted we find, e.g., the non-exponentiality parameter K (p) = 1 - <N(P)> (p)! <N>(p) to decay as K (p) approximately equal to 1/ (sqrt[<N>]) for all moments p of the distribution.

Statutory zoning and the environment

PurposeThe purpose of this paper is to develop a hypothesis for evaluating the potential contribution of planning conditions to protect the environment by reducing environmental complaints (ECs) in an institutional context of growing communicative planning and interpret the results of an empirical study using two received hypotheses in terms of sustainable development in the light of the actual participation of the public in influencing the formulation of planning conditions.Design/methodology/approachThe hypothesis is tested using Environmental Protection Department EC and Planning Department zoning data. In addition, field observation of the conduct the Town Planning Board in their open sessions is made over a period of 27 months.FindingsThe hypothesis about the frequency of planning permissions and the incidence of ECs using the “received” model of Lai is refuted. The results for testing Lai's model on the relationship between Comprehensive Development Area zoning and ECs are indecisive. Though a negative correlation between zoning and complaints is established, the strength of such correlation is insignificant for each of the specified periods.Research limitations/implicationsThe promise of communicative theorists about empowering the public in planning has yet to be fulfilled in terms of contribution to the shaping of planning conditions. Official suppression of addresses of locations of the occurrence of ECs does not allow the ideal hypothesis to be tested.Practical implicationsSubject to further and better qualitative research, the limitations of the new public participation law in planning for shaping planning conditions are revealed by an examination of observed facts about the time spent by the Town Planning Board in decision making and the nature of the planning conditions imposed in response to public comments.Originality/valueThe paper demonstrates an approach to evaluate the direct means of measuring the relationship between externalities and zoning with a view to interpret the contribution of planning conditions to sustainable development.

Comparison between Ideal and Nonideal Solution Models for Single-Cell Cryopreservation Protocols

Models for cell dehydration during a cryopreservation protocol are usually based on the hypothesis of ideal dilute solution. The strong electrolyte character of NaCl makes us revisit these models. The case of nonideal solution is analyzed by computing the dehydration curves without this additional hypothesis. The conclusion is that, in general, while the application of the ideal dilute solution hypothesis is convenient in many cases, for some specific cooling rates there exist important differences in the degree of dehydration predicted by these two models in the studied cases of mouse sperm and hepatocyte. It is shown how this finding has relevant implications for the design and optimization of cryopreservation protocols.

Causes and consequences of distribution patterns in a migratory songbird across its geographic range

The ideal distribution hypothesis states that territorial animals identify habitats with ideal habitat suitability and alter their settlement patterns accordingly. This hypothesis assumes no cost of migrating to a more profitable patch once the current one becomes less profitable. Another underlying assumption is that individuals only use current information while deciding where to breed. To evaluate these assumptions and resultant alternative hypotheses, we studied Ovenbird ( Seiurus aurocapilla (L., 1766)) territories during 2000–2001 in six northern hardwood tracts within a landscape composed of wetlands, regenerating stands, small farms and roads. We incorporated data from our own study and from published studies across the Ovenbird geographic range, using an information-theoretic approach. Contrary to the ideal distribution hypothesis, Ovenbird territory density increased with upland openings, but density was similar across clearcut-edge-distance and forest-thinning categories. Relationships between reproduction and territory density were uncertain and therefore provided little evidence against the ideal free distribution hypothesis, but there was some evidence in favor of the alternative costly migration and ideal dominance hypotheses from the analysis of our own data and the meta-analysis, respectively. Finally, territories became denser when fecundity and pairing success were high during the previous year, and this supports the public information hypothesis. We recommend using measures of reproductive success in conjunction with territory density when assessing population status.

Static Rouse modes and related quantities: Corrections to chain ideality in polymer melts

Following the Flory ideality hypothesis intrachain and interchain excluded-volume interactions are supposed to compensate each other in dense polymer systems. Multichain effects should thus be neglected and polymer conformations may be understood from simple phantom chain models. Here we provide evidence against this phantom chain, mean-field picture. We analyze numerically and theoretically the static correlation function of the Rouse modes. Our numerical results are obtained from computer simulations of two coarse-grained polymer models for which the strength of the monomer repulsion can be varied, from full excluded volume ("hard monomers") to no excluded volume ("phantom chains"). For nonvanishing excluded volume we find the simulated correlation function of the Rouse modes to deviate markedly from the predictions of phantom chain models. This demonstrates that there are nonnegligible correlations along the chains in a melt. These correlations can be taken into account by perturbation theory. Our simulation results are in good agreement with these new theoretical predictions.

Two-Phase Shrinking Porous Media Drying: A Modeling Approach Including Liquid Pressure Gradients Effects

This article deals with the drying modeling of a saturated deformable porous media (solid + fluid). This modeling takes into account the mechanical behavior of the product as well as its initial conditions such as its moisture content and geometry. The effect of fluid pressure gradient on the fluid transfer is described by using Darcy's law, and the fluid compressibility is characterized by its bulk modulus of elasticity. The solid phase is supposed to be incompressible and the porous media permanently diphasic (ideal shrinkage hypothesis). The description of the strong thermo-hydro-mechanical coupling that takes place within the material during drying is taken into account in the light of Biot's consolidation theory by adopting Terzaghi's effective stress principle. The numerical resolution is performed by FEM and ALE methods. A comparison between experimental results (convective drying of an alumina gel) and numerical results improves the ability of this modeling to describe thermo-hydro-mechanical coupling. It further highlights a current lack of precision in the determination of the thermophysical parameters values that control the model.

Intramolecular long-range correlations in polymer melts: The segmental size distribution and its moments

We present theoretical arguments and numerical results to demonstrate long-range intrachain correlations in concentrated solutions and melts of long flexible polymers, which cause a systematic swelling of short chain segments. They can be traced back to the incompressibility of the melt leading to an effective repulsion u(s) approximately s/rho R3(s) approximately c(e)/sqrt[s] when connecting two segments together where s denotes the curvilinear length of a segment, R(s) its typical size, c(e) approximately 1/rho b(e)3 the "swelling coefficient," b(e) the effective bond length, and rho the monomer density. The relative deviation of the segmental size distribution from the ideal Gaussian chain behavior is found to be proportional to u(s). The analysis of different moments of this distribution allows for a precise determination of the effective bond length b(e) and the swelling coefficient c(e) of asymptotically long chains. At striking variance to the short-range decay suggested by Flory's ideality hypothesis the bond-bond correlation function of two bonds separated by s monomers along the chain is found to decay algebraically as 1/s(3/2). Effects of finite chain length are briefly considered.

Intramolecular Form Factor in Dense Polymer Systems: Systematic Deviations from the Debye Formula

We discuss theoretically and numerically the intramolecular form factor $F(q)$ in dense polymer systems. Following Flory's ideality hypothesis, chains in the melt adopt Gaussian configurations and their form factor is supposed to be given by Debye's formula. At striking variance to this, we obtain noticeable (up to 20%) non-monotonic deviations which can be traced back to the incompressibility of dense polymer solutions beyond a local scale. The Kratky plot ($q^2F(q)$ {\it vs.} wavevector $q$) does not exhibit the plateau expected for Gaussian chains in the intermediate $q$-range. One rather finds a significant decrease according to the correction $\delta(F^{-1}(q)) = q^3/32\rho$ that only depends on the concentration $\rho$ of the solution, but neither on the persistence length or the interaction strength.

Extending En for measurement science

For metrology to be recognized as a measurement science, it must be seen to be using the scientific method. This requires metrologists to make predictions that can be tested and validated by experiment. The fundamental testable prediction is usually a variant of ‘agreement within the claimed uncertainty’, and the experiment is usually a comparison of two or more nominally identical measurements. The normalized error, En, can be generalized as the ratio of {a difference of the two values} to {the standard uncertainty in the difference of the two values}. This definition can apply equally to the difference between a particular measurement and a reference value with an uncertainty or to an unmediated bilateral difference between two measurements considered as peers. This latter interpretation leads to the creation of a family of bilateral En values in a comparison, which can be aggregated by taking the root-mean-square (RMS) average. This RMS En is a norm that can support intuitive ideas of ordering performance in the comparison. The mean-square En is a chi-squared-like statistic and can be evaluated by Monte Carlo simulation to perform quantitative tests of the ideal agreement hypothesis for a comparison. The use of these statistics in broader aggregates is discussed: averaging across similar unlinked key/regional comparisons, across a range of artefact values, across different principal measurement techniques in a given metrology area or even across all major metrology areas spanning the entire International System of Units. Each of these ‘averages’ can be done as an overall aggregate of all participants or can focus on one particular participant's RMS En aggregated with respect to all its peers' results.

Itinéraires du XIXe siècle ed. by Roland Le Huenen, Stéphane Vachon (review)

780 Reviews abiding difficultyof making a generic classification of Emile is a recurrent theme here, and the difficultyitself, rather than any radical attempt to resolve it, shapes Mall's work. Thus, the tension between treatise and novel forms is apparent each time that Emile is used as an example. That is one aspect of the use of examples, but Mall will examine at length the question of exemplarity in the work, disentangling its many functions, some of which are linked loosely if at all to the distinction between novel and treatise. Emile, who is in any case not the only example invoked, must be unique, in order to demonstrate the truth of the new method, yet capable of generalization in order to prove its utility. He is regularly an ideal hypothesis but occasionally gives a bad example, so briefly representing a banal social norm rather than the alternative vision in which he generally has his place. Mall is excellent on everything relating to enunciation, clearly one of the most difficultissues for the reader of Emile. Mall shows how the authorial je disqualifies itself, rejecting any basis in experience for the foundation of a new order of education, making the Governor a necessary figure, although one who is nevertheless identified with the author by more or less ambigu? ous means. In her last chapter she takes up the issues of enunciation raised by the Profession de foi du vicaire savoyard, developing the notion of 'vicariance' generally, and ofthe substitution of one voice foranother in particular. In her meticulous sifting ofthe text, she also reminds us that the discourse ofthe vicaire is situated in relation to religious institutions, whereas the rest of the educational process described is cut offfrom institutions. That is typical of her ability to formulate general observations and judgements on the solid base provided by her detailed analyses. If Mall rejects the easy assurance of those who see only a treatise on education in Emile, she never fails into an excessive literalism that would block all global readings of the text. Her conclusion regarding the double allegiance of the work is this: 'La fiction d'Emile ne developpe pas, n'illustre pas une theorie anterieure ou separee qui serait, elle, non fictive : la theorie est l'autre face de la fiction, son autre figure' (p. 318). Quoted thus, the judgement may seem unsurprising, but the reader who follows the thread of this rich study,difficultto describe adequately in a short review because so much of its richness lies in the subtlety of the detailed readings, will know that the author has illuminated the text to an extent that has rarely been accomplished previously. This is a book to change our ways of thinking about Emile and to stimulate reflection on issues of enunciation and multiple voices throughout Rousseau's work. It is essential reading. Universite Lyon II Lumiere Michael O'Dea Itinerairesdu XIXe siecle, vol. ii. Ed. by Roland Le Huenen and Stephane Vachon. (A la recherche du xixe siecle, 6) Toronto: Centre d'etudes du xixe siecle Joseph Sable. 2001. 199 pp. ?IQ05; $28.49. ISBN 0-7727-8909-6. Drawing attention to the writings ofVictor Jacquemont, who leftrecords ofhis scien? tificexpedition to northern India in the 1830s, Yannick Resch argues that the young man's letters home are of particular interest. When Sonia Sapienza explores Charles Nodier's account of his trip from Dieppe to the Scottish Highlands, she too concen? trates more on literary than topographical aspects, and she points up the influence of Sterne's Sentimental Journey. Travellers' tales are not, however, the subject of most of the dozen papers by specialists from the French Departments of the Universities of Toronto and Montreal that are presented here. As the editors explain, readers should not be taken in by ia couleur proustienne du titre de cette collection' (p. 3); the focus is rather on the ceaseless transformations that they see as the essence of French cultural life in the nineteenth century. With its essays on major writers of the period, the volume as a whole lends support to that assertion. It hardly seems worth MLR, 99.3, 2004 781 debating, however, the rhetorical question whether or...

Roland Le Huenen (review)

780 Reviews abiding difficultyof making a generic classification of Emile is a recurrent theme here, and the difficultyitself, rather than any radical attempt to resolve it, shapes Mall's work. Thus, the tension between treatise and novel forms is apparent each time that Emile is used as an example. That is one aspect of the use of examples, but Mall will examine at length the question of exemplarity in the work, disentangling its many functions, some of which are linked loosely if at all to the distinction between novel and treatise. Emile, who is in any case not the only example invoked, must be unique, in order to demonstrate the truth of the new method, yet capable of generalization in order to prove its utility. He is regularly an ideal hypothesis but occasionally gives a bad example, so briefly representing a banal social norm rather than the alternative vision in which he generally has his place. Mall is excellent on everything relating to enunciation, clearly one of the most difficultissues for the reader of Emile. Mall shows how the authorial je disqualifies itself, rejecting any basis in experience for the foundation of a new order of education, making the Governor a necessary figure, although one who is nevertheless identified with the author by more or less ambigu? ous means. In her last chapter she takes up the issues of enunciation raised by the Profession de foi du vicaire savoyard, developing the notion of 'vicariance' generally, and ofthe substitution of one voice foranother in particular. In her meticulous sifting ofthe text, she also reminds us that the discourse ofthe vicaire is situated in relation to religious institutions, whereas the rest of the educational process described is cut offfrom institutions. That is typical of her ability to formulate general observations and judgements on the solid base provided by her detailed analyses. If Mall rejects the easy assurance of those who see only a treatise on education in Emile, she never fails into an excessive literalism that would block all global readings of the text. Her conclusion regarding the double allegiance of the work is this: 'La fiction d'Emile ne developpe pas, n'illustre pas une theorie anterieure ou separee qui serait, elle, non fictive : la theorie est l'autre face de la fiction, son autre figure' (p. 318). Quoted thus, the judgement may seem unsurprising, but the reader who follows the thread of this rich study,difficultto describe adequately in a short review because so much of its richness lies in the subtlety of the detailed readings, will know that the author has illuminated the text to an extent that has rarely been accomplished previously. This is a book to change our ways of thinking about Emile and to stimulate reflection on issues of enunciation and multiple voices throughout Rousseau's work. It is essential reading. Universite Lyon II Lumiere Michael O'Dea Itinerairesdu XIXe siecle, vol. ii. Ed. by Roland Le Huenen and Stephane Vachon. (A la recherche du xixe siecle, 6) Toronto: Centre d'etudes du xixe siecle Joseph Sable. 2001. 199 pp. ?IQ05; $28.49. ISBN 0-7727-8909-6. Drawing attention to the writings ofVictor Jacquemont, who leftrecords ofhis scien? tificexpedition to northern India in the 1830s, Yannick Resch argues that the young man's letters home are of particular interest. When Sonia Sapienza explores Charles Nodier's account of his trip from Dieppe to the Scottish Highlands, she too concen? trates more on literary than topographical aspects, and she points up the influence of Sterne's Sentimental Journey. Travellers' tales are not, however, the subject of most of the dozen papers by specialists from the French Departments of the Universities of Toronto and Montreal that are presented here. As the editors explain, readers should not be taken in by ia couleur proustienne du titre de cette collection' (p. 3); the focus is rather on the ceaseless transformations that they see as the essence of French cultural life in the nineteenth century. With its essays on major writers of the period, the volume as a whole lends support to that assertion. It hardly seems worth MLR, 99.3, 2004 781 debating, however, the rhetorical question whether or...