bluuebunny/crossref_metadata_2025_split huggingface dataset:
Statistical Issues in fMRI for Brain Imaging
Authors: Lazar Nicole A. , Eddy William F. , Genovese Christopher R. , Welling Joel 
Published: May 2007

SummaryFunctional magnetic resonance imaging is a technique developed in the last decade and used in the fields of cognitive psychology and neuroscience, among others, to study the processes underlying the working of the human brain. In this paper we examine some of the statistical issues in functional magnetic resonance imaging for brain research. We start by giving a brief introduction to the physics of magnetic resonance imaging. Using a psychological experiment as a case study, we then describe questions of design and statistical analysis. The data obtained from functional magnetic resonance imaging studies are of a highly complex nature, displaying both spatial and temporal correlation, as well as high levels of noise from different sources. Given this, the scope for statistics is vast, and is not limited to simple analysis of the data, once collected.
Signal Extraction Problems in Seismology*
Authors: Kitagawa Genshiro , Takanami Tetsuo , Matsumoto Norio 
Published: May 2007

SummaryThe earth's surface is under continuous influence of a variety of natural forces such as the effect of past earthquakes, wave, wind, tide, air pressure, precipitation and a variety of human induced sources. Since it is almost impossible to describe the response to these noise inputs precisely, for automatic processing of seismic data, proper statistical modeling is necessary. In this paper, we describe four specific examples of time series modeling for signal extraction problems related to seismology. Namely, we consider 1) the estimation of the arrival time of a seismic signal, 2) the extraction of small seismic signal from noisy data, 3) the detection of the coseismic effect in groundwater level data contaminated by various effects from air pressure etc., and 4) the estimation of changing spectral characteristic of seismic record.
Adults' Statistical Literacy: Meanings, Components, Responsibilities
Authors: Gal Iddo 
Published: May 2007

SummaryStatistical literacy is a key ability expected of citizens in information‐laden societies, and is often touted as an expected outcome of schooling and as a necessary component of adults’numeracy and literacy. Yet, its meaning and building blocks have received little explicit attention. This paper proposes a conceptualization of statistical literacy and describes its key components. Statistical literacy is portrayed as the ability to interpret, critically evaluate, and communicate about statistical information and messages. It is argued that statistically literate behavior is predicated on the joint activation of five interrelated knowledge bases (literacy, statistical, mathematical, context, and critical), together with a cluster of supporting dispositions and enabling beliefs. Educational and research implications are discussed, and responsibilities facing educators, statisticians, and other stakeholders are outlined.
What Makes Business Statistics Special?
Authors: Riviére Pascal 
Published: May 2007

SUMMARYNon‐specialists might have the feeling that building statistics on businesses is a very simple task: it seems one just has to “add facts”. But for survey statisticians, business statistics are extremely complex: great heterogeneity of the universe, definition of the statistical units, difficulty of classifying businesses, quality of the register, variety of accounting standards, sample co‐ordination, or reduction of survey burden. This paper argues that the issues raised by business survey methodology are conceptual and not only practical. It describes different aspects of statistical processing and tries to analyse the special features of business statistics.
MC's for MCMC'ists
Authors: Nummelin Esa 
Published: May 2007

SummaryWe develop a minimum amount of theory of Markov chains at as low a level of abstraction as possible in order to prove two fundamental probability laws for standard Markov chain Monte Carlo algorithms:1. The law of large numbers explains why the algorithm works: it states that the empirical means calculated from the samples converge towards their “true” expected values, viz. expectations with respect to the invariant distribution of the associated Markov chain (=the target distribution of the simulation).2. The central limit theorem expresses the deviations of the empirical means from their expected values in terms of asymptotically normally distributed random variables. We also present a formula and an estimator for the associated variance.
OBITUARY NATHAN JACOBSON (1910–1999)
Authors: COHN P. M. 
Published: May 2007

Nathan Jacobson, who died on 5 December 1999, was an outstanding algebraist,
whose work on almost all aspects of algebra was of fundamental importance, and
whose writings will exercise a lasting influence. He had been an honorary member
of the Society since 1972.Nathan Jacobson (later known as ‘Jake’ to his friends) was born in Warsaw (in
what he describes as the ‘Jewish ghetto’) on 5 October 1910 (through an error some
documents have the date 8 September); he was the second son of Charles Jacobson
(as he would be known later) and his wife Pauline, née Rosenberg. His family
emigrated to the USA during the First World War, first to Nashville, Tennessee,
where his father owned a small grocery store, but they then settled in Birmingham,
Alabama, where Nathan received most of his schooling. Later the family moved to
Columbus, Mississippi, but the young Nathan entered the University of Alabama
in 1926 and graduated in 1930. His initial aim was to follow an uncle and obtain a
degree in law, but at the same time he took all the (not very numerous) mathematics
courses, in which he did so well that he was offered a teaching assistantship in
mathematics in his junior (3rd) year. This marked a turning point; he now decided
to major in mathematics and pursue this study beyond College. During his final
year at Alabama he applied for admission and financial aid to three top graduate
schools in the country: Princeton, Harvard and Chicago. He was awarded a research
assistantship at Princeton; after the first year he was appointed a part-time instructor
for two years, and during his fourth year he was appointed a Procter Fellow. The
stipend was enough to enable him to make a grand tour of Europe by car in 1935,
in the company of two Princeton fellow-students at the time: H. F. Bohnenblust and
Robert J. Walker.
THE HEAT FLOW OF THE CCR ALGEBRA
Authors: ARVESON WILLIAM 
Published: May 2007

Let Pf(x) =−if′(x) and Qf(x) = xf(x) be the canonical operators acting on an appropriate common
dense domain in L2(ℝ). The derivations DP(A) = i(PA−AP) and DQ(A) = i(QA−AQ) act on the
*-algebra [Ascr ] of all integral operators having smooth kernels of compact support, for example, and one
may consider the noncommutative ‘Laplacian’, L = D2P+D2Q, as a linear mapping of [Ascr ] into itself.L generates a semigroup of normal completely positive linear maps on [Bscr ](L2(ℝ)), and this paper
establishes some basic properties of this semigroup and its minimal dilation to an E0-semigroup. In
particular, the author shows that its minimal dilation is pure and has no normal invariant states, and he
discusses the significance of those facts for the interaction theory introduced in a previous paper.There are similar results for the canonical commutation relations with n degrees of freedom, where
1 [les ] n < 1.
CONES OF CURVES AND OF LINE BUNDLES ON SURFACES ASSOCIATED WITH CURVES HAVING ONE PLACE AT INFINITY
Authors: CAMPILLO ANTONIO , PILTANT OLIVIER , REGUERA-LÓPEZ ANA J. 
Published: May 2007

Let V be a pencil of curves in ${\bf P}^2$ with one place at infinity, and $X \longrightarrow {\bf P}^2$ the minimal composition of point blow-ups eliminating its base locus. We study the cone of curves and the cones of numerically effective and globally generated line bundles on X. It is proved that all of these cones are regular. In particular, this result provides a new class of rational projective surfaces with a rational polyhedral cone of curves. The surfaces in this class have non-numerically effective anticanonical sheaf if the pencil is neither rational nor elliptic.
An application is a global version on X of Zariski's unique factorization theorem for complete ideals. We also define invariants of the semigroup of globally generated line bundles on X depending only on the topology of V at infinity.2000 Mathematical Subject Classification: primary 14C20; secondary 14E05.
FANS AND LADDERS IN SMALL CANCELLATION THEORY
Authors: McCAMMOND JONATHAN P. , WISE DANIEL T. 
Published: May 2007

This paper provides a strengthening of the theorems of small cancellation theory. It is proven that disc diagrams contain 'fans' of consecutive 2-cells along their boundaries. The size of these fans is linked to the strength of the small cancellation conditions satisfied by the diagram. A classification result is proven for disc diagrams satisfying small cancellation conditions. Any disc diagram either contains three fans along its boundary, or it is a ladder, or it is a wheel. Similar statements are proven for annular diagrams. 2000 Mathematical Subject Classification: 20F06.
A BANACH SPACE WHOSE OPERATOR ALGEBRA HAS K0-GROUP ℚ
Authors: ZSÁK ANDRÁS 
Published: May 2007

We construct a Banach space X whose algebra of bounded linear operators has K0-group the additive group of rational numbers. We achieve this using a Gowers-Maurey space.2000 Mathematical Subject Classification: 20F36, 55P35, 55Q05, 55Q40, 55U10
Sharks need the lateral line to locate odor sources: rheotaxis and eddy chemotaxis
Authors: Gardiner Jayne M. , Atema Jelle 
Published: May 2007

SUMMARY
Odor plumes are complex, dynamic, three-dimensional structures used by many animals to locate food, mates, home sites, etc. Yet odor itself has no directional properties. Animals use a variety of different senses to obtain directional information. Since most odor plumes are composed of dispersing odor patches and dissipating vorticity eddies, aquatic animals may localize odor sources by simultaneous analysis of chemical and hydrodynamic dispersal fields, a process referred to as eddy chemotaxis. This study examines the contributions of olfaction, mechanoreception and vision to odor source localization in a shark, the smooth dogfish Mustelus canis. Two parallel, turbulent plumes were created in an 8 m flume: squid rinse odor and seawater control. Minimally turbulent `oozing' sources of odor and seawater control were physically separated from sources of major turbulence by placing a brick downstream from each oozing source, creating two turbulent wakes, one or the other flavored with food odor. This created four separate targets for the sharks to locate. Animals were tested under two light conditions(fluorescent and infrared) and in two sensory conditions (lateral line intact and lateral line lesioned by streptomycin). Intact animals demonstrated a preference for the odor plume over the seawater plume and for the source of odor/turbulence (the brick on the odor side) over the source of the odor alone(the odor-oozing nozzle). Plume and target preference and search time were not significantly affected by light condition. In the light, lesioning the lateral line increased search time but did not affect success rate or plume preference. However, lesioned animals no longer discriminated between sources of turbulent and oozing odor. In the dark, search time of lesioned animals further increased, and the few animals that located any of the targets did not discriminate between odor and seawater plumes, let alone targets. These results demonstrate for the first time that sharks require both olfactory and lateral line input for efficient and precise tracking of odor-flavored wakes and that visual input can improve food-finding performance when lateral line information is not available. We distinguish between rheotaxis: orientation to the large-scale flow field (olfaction, vision and superficial lateral line),eddy chemotaxis: tracking the trail of small-scale, odor-flavored turbulence(olfaction and lateral line canals), and pinpointing the source of the plume(lateral line canals and olfaction).
Metabolic rate of nocturnal incubation in female great tits,Parus major, in relation to clutch size measured in a natural environment
Authors: de Heij Maaike E. , van der Graaf Alexandra J. , Hafner Dennis , Tinbergen Joost M. 
Published: May 2007

SUMMARYTo study the energetic costs of incubation in relation to clutch size,clutch sizes were manipulated and the metabolic rate of female great tits, Parus major (Linnaeus), during nocturnal incubation(MRinc) was measured using mobile oxygen analysers. Individuals were measured on consecutive nights while incubating their own or manipulated clutches. The experiment was performed under field conditions in order to place possible effects of clutch size manipulation within the context of other factors explaining variation in MRinc. Females spent more energy when incubating enlarged clutches as compared with controls(6–10% more energy for three additional eggs) but did not spend significantly less energy when incubating reduced clutches. MRinc was strongly negatively related to ambient temperature. The effect of clutch enlargement is consistent with previous studies whereas the absence of an effect of clutch reduction is not. The small effect of clutch enlargement on MRinc highlights the need for further studies to include measurements of daily energy expenditure in order to judge how important energy expenditure can be in explaining fitness consequences of incubating experimentally enlarged clutches.
Behavioural and physiological responses to increased foraging effort in male mice
Authors: Vaanholt Lobke M. , De Jong Berber , Garland Theodore , Daan Serge , Visser G. Henk 
Published: May 2007

SUMMARY
Free-living animals must forage for food and hence may face energetic constraints imposed by their natural environmental conditions (e.g. ambient temperature, food availability). Simulating the variation in such constraints,we have experimentally manipulated the rate of work (wheel running) mice must do to obtain their food, and studied the ensuing behavioural and physiological responses. This was done with a line of mice selectively bred for high spontaneous wheel running and a randomly bred control line that vary in the amount of baseline wheel-running activity. We first determined the maximum workload for each individual. The maximum workload animals could engage in was around 23 km d–1 in both control and activity-selected mice,and was not associated with baseline wheel-running activity. We then kept mice at 90% of their individual maximum and measured several physiological and behavioural traits. At this high workload, mice increased wheel-running activity from an average of 10 to 20 km d–1, and decreased food intake and body mass by approximately 20%. Mass-specific resting metabolic rate strongly decreased from 1.43 to 0.98 kJ g–1d–1, whereas daily energy expenditure slightly increased from 2.09 to 2.25 kJ g–1 d–1. Costs of running decreased from 2.3 to 1.6 kJ km–1 between baseline and workload conditions. At high workloads, animals were in a negative energy balance, resulting in a sharp reduction in fat mass as well as a slight decrease in dry lean mass. In addition, corticosterone levels increased, and body temperature was extremely low in some animals at high workloads. When challenged to work for food, mice thus show significant physiological and behavioural adjustments.
Morphological diversity of medusan lineages constrained by animal–fluid interactions
Authors: Dabiri John O. , Colin Sean P. , Costello John H. 
Published: May 2007

SUMMARYCnidarian medusae, commonly known as jellyfish, represent the earliest known animal taxa to achieve locomotion using muscle power. Propulsion by medusae requires the force of bell contraction to generate forward thrust. However, thrust production is limited in medusae by the primitive structure of their epitheliomuscular cells. This paper demonstrates that constraints in available locomotor muscular force result in a trade-off between high-thrust swimming via jet propulsion and high-efficiency swimming viaa combined jet-paddling propulsion. This trade-off is reflected in the morphological diversity of medusae, which exhibit a range of fineness ratios(i.e. the ratio between bell height and diameter) and small body size in the high-thrust regime, and low fineness ratios and large body size in the high-efficiency regime. A quantitative model of the animal–fluid interactions that dictate this trade-off is developed and validated by comparison with morphological data collected from 660 extant medusan species ranging in size from 300 μm to over 2 m. These results demonstrate a biomechanical basis linking fluid dynamics and the evolution of medusan bell morphology. We believe these to be the organising principles for muscle-driven motility in Cnidaria.
Allatotropin-like peptide released by Malpighian tubules induces hindgut activity associated with diuresis in the Chagas disease vector Triatoma infestans (Klug)
Authors: Santini Maria Soledad , Ronderos Jorge Rafael 
Published: May 2007

SUMMARY
Haematophagous insects incorporate a large amount of blood with each meal,producing a big quantity of urine in a few hours to eliminate the excess water and Na+. Malpighian tubules (MTs) have traditionally been seen as a system that responds to neuroendocrine stimulus. In a related paper, we demonstrated that MTs of Triatoma infestans produce an autonomous endocrine secretion of an allatotropin-like (AT-like) peptide. In the present study, we report a myostimulatory activity of AT at the level of the hindgut(HG), associated with endocrine mechanisms regulating post-prandial diuresis. Allatotropin induced an increase in frequency and intensity of peristaltic contractions at the level of the HG. The release of the HG content in MTs–HG in vitro preparations undergoing an osmotic shock occurred at different times, depending on the number of MTs present, and there was no release in treatments without MTs. The application of an AT-antiserum to MTs–HG preparations undergoing osmotic shock produced a delay or a long-term blockade of diuresis, depending on the antiserum dilution applied. Similar results were obtained when AT-antiserum was applied in vivoprior to blood intake, decreasing the volume of urine eliminated during the first 2 h. Our results allow us to assign a specific endocrine function to the AT-like peptide released by MTs that is linked to the elimination of urine after blood meals.
Diving and foraging energetics of the smallest marine mammal, the sea otter (Enhydra lutris)
Authors: Yeates Laura C. , Williams Terrie M. , Fink Traci L. 
Published: May 2007

SUMMARYAs the smallest and one of the most recently evolved marine mammals, sea otters face physiological challenges rarely encountered by larger, more derived aquatic species. To examine the effect of these challenges on foraging costs and resultant daily energy budgets, we measured the energetics of resting, grooming, diving and foraging for adult, male sea otters. The energy expended for these different behaviors as determined from open flow respirometry was then standardized across activity budgets measured for wild sea otters to estimate field metabolic rates (FMR). We found that the metabolic rate of captive otters performing single dives ranging in duration from 40 to 192 s was 17.6±0.5 ml O2 kg–1min–1 and only 1.3 times resting rates. This rate increased significantly if the animals foraged during submergence. The cost of a foraging dive for sea otters was nearly twice that predicted for phocid seals,which was attributed in part to elevated locomotor costs associated with buoyancy and swimming style. Our behavioral studies indicate that wild sea otters spend the greatest proportion of the day feeding and resting, with the largest daily energy expenditure (6.1±1.1 MJ day–1)associated with foraging. The resulting mean FMR for wild sea otters based on the energy expended for all behaviors was 15.7±2.7 MJ day–1 and matched predicted FMR values based upon a regression of known FMR values for other marine mammals across a range of body sizes. This was achieved by counterbalancing elevated foraging costs with prolonged periods of rest on the water surface.
Interspecific comparison of hydrodynamic performance and structural properties among intertidal macroalgae
Authors: Boller Michael L. , Carrington Emily 
Published: May 2007

SUMMARY
Macroalgae use flexibility and reconfiguration, i.e. the alteration of shape, size and orientation as water velocity increases, to reduce the hydrodynamic forces imposed in the wave-swept rocky intertidal zone. Quantifying the effects of flexibility on hydrodynamic performance is difficult, however, because the mechanisms of reconfiguration vary with water velocity and the relationship between algal solid mechanics and hydrodynamic performance is poorly understood. In this study, the hydrodynamic performance,morphology and solid mechanics of 10 rocky shore macroalgal species were quantified to evaluate the influences of flexibility and morphology on reconfiguration. Hydrodynamic performance was measured in a flume by direct measurement of changes in size and shape during reconfiguration across a wide range of velocities, material stiffness was quantified with standard materials testing, and structural properties were calculated from material and morphological data. Hydrodynamic parameters varied significantly among species, indicating variation in the magnitude of reconfiguration and the velocities required for full reconfiguration. Structural properties also varied among species, and were correlated with hydrodynamic performance in some instances. The relationship between hydrodynamic and structural properties is velocity dependent, such that flexibility influences different aspects of reconfiguration at low and high velocities. Groups are identifiable among species based on hydrodynamic and structural properties, suggesting that these properties are useful for addressing functional-form hypotheses and the effects of hydrodynamic disturbance on macroalgal communities.