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Showing papers by "University of St Andrews published in 1998"


Journal ArticleDOI
TL;DR: This paper focuses on bilateral ventrolateral prefrontal responses that show deactivations for previously seen words and activations for novel words in functional magnetic resonance imaging that are evoked by different sorts of stimuli.

2,049 citations


Journal ArticleDOI
27 Aug 1998-Nature
TL;DR: The results of asking subjects to choose the most attractive faces from continua that enhanced or diminished differences between the average shape of female and male faces indicate a selection pressure that limits sexual dimorphism and encourages neoteny in humans.
Abstract: Testosterone-dependent secondary sexual characteristics in males may signal immunological competence1 and are sexually selected for in several species2,3. In humans, oestrogen-dependent characteristics of the female body correlate with health and reproductive fitness and are found attractive4,5,6. Enhancing the sexual dimorphism of human faces should raise attractiveness by enhancing sex-hormone-related cues to youth and fertility in females5,7,8,9,10,11, and to dominance and immunocompetence in males5,12,13. Here we report the results of asking subjects to choose the most attractive faces from continua that enhanced or diminished differences between the average shape of female and male faces. As predicted, subjects preferred feminized to average shapes of a female face. This preference applied across UK and Japanese populations but was stronger for within-population judgements, which indicates that attractiveness cues are learned. Subjects preferred feminized to average or masculinized shapes of a male face. Enhancing masculine facial characteristics increased both perceived dominance and negative attributions (for example, coldness or dishonesty) relevant to relationships and paternal investment. These results indicate a selection pressure that limits sexual dimorphism and encourages neoteny in humans.

1,186 citations


Journal ArticleDOI
19 Feb 1998-Nature
TL;DR: It is shown that dispersal and interactions, which are important elements of population dynamics, must be included in predictions of biotic responses to climate change.
Abstract: Many attempts to predict the biotic responses to climate change rely on the 'climate envelope' approach, in which the current distribution of a species is mapped in climate-space and then, if the position of that climate-space changes, the distribution of the species is predicted to shift accordingly. The flaw in this approach is that distributions of species also reflect the influence of interactions with other species, so predictions based on climate envelopes may be very misleading if the interactions between species are altered by climate change. An additional problem is that current distributions may be the result of sources and sinks, in which species appear to thrive in places where they really persist only because individuals disperse into them from elsewhere. Here we use microcosm experiments on simple but realistic assemblages to show how misleading the climate envelope approach can be. We show that dispersal and interactions, which are important elements of population dynamics, must be included in predictions of biotic responses to climate change.

1,161 citations


Journal ArticleDOI
TL;DR: The authors solve the coherence optimization problem involving maximization of interferometric coherence and formulate a new coherent decomposition for polarimetric SAR interferometry that allows the separation of the effective phase centers of different scattering mechanisms.
Abstract: The authors examine the role of polarimetry in synthetic aperture radar (SAR) interferometry. They first propose a general formulation for vector wave interferometry that includes conventional scalar interferometry as a special case. Then, they show how polarimetric basis transformations can be introduced into SAR interferometry and applied to form interferograms between all possible linear combinations of polarization states. This allows them to reveal the strong polarization dependency of the interferometric coherence. They then solve the coherence optimization problem involving maximization of interferometric coherence and formulate a new coherent decomposition for polarimetric SAR interferometry that allows the separation of the effective phase centers of different scattering mechanisms. A simplified stochastic scattering model for an elevated forest canopy is introduced to demonstrate the effectiveness of the proposed algorithms. In this way, they demonstrate the importance of wave polarization for the physical interpretation of SAR interferograms. They investigate the potential of polarimetric SAR interferometry using results from the evaluation of fully polarimetric interferometric shuttle imaging radar (SIR)-C/X-SAR data collected during October 8-9, 1994, over the SE Baikal Lake Selenga delta region of Buriatia, Southeast Siberia, Russia.

1,013 citations


Journal ArticleDOI
TL;DR: In this article, a modified IkappaBalpha, conjugated to the small ubiquitin-like protein SUMO-1, which is resistant to signal-induced degradation, was detected.

962 citations


Journal ArticleDOI
28 Mar 1998-BMJ
TL;DR: Odds ratios are a common measure of the size of an effect and may be reported in case-control studies, cohort studies, or clinical trials, and are also used to report the findings from systematic reviews and meta-analyses.
Abstract: Odds ratios are a common measure of the size of an effect and may be reported in case-control studies, cohort studies, or clinical trials. Increasingly, they are also used to report the findings from systematic reviews and meta-analyses. Odds ratios are hard to comprehend directly and are usually interpreted as being equivalent to the relative risk. Unfortunately, there is a recognised problem that odds ratios do not approximate well to the relative risk when the initial risk (that is, the prevalence of the outcome of interest) is high. 1 2 Thus there is a danger that if odds ratios are interpreted as though they were relative risks then they may mislead. The advice given in many texts is unusually coy on the matter. For example: “The odds ratio is approximately the same as the relative risk if the outcome of interest is rare. For common events, however, they can be quite different.”3 How close is “approximately the same,” how uncommon does an event have to be to qualify as “rare,” and how different is “quite different”? #### Summary points If the odds ratio is interpreted as a relative risk it will always overstate any effect size: the odds ratio is smaller than the relative risk for odds ratios of less than one, and bigger than the relative risk for odds ratios of greater than one The extent of overstatement increases as both the initial risk increases and the odds ratio departs from unity However, serious divergence between the odds ratio and the relative risk occurs only with large effects on groups at high initial risk. Therefore qualitative judgments based on interpreting odds ratios as though they were relative risks are unlikely to be seriously in error In studies which show reductions in risk (odds ratios of less than one), the odds ratio …

839 citations


Proceedings Article
01 Jan 1998
TL;DR: In this article, the role of polarimetry in synthetic aperture radar (SAR) interferometry is examined and a coherent decomposition for polarimetric SAR inter-ferometry that allows the separation of the effective phase centers of different scattering mechanisms is introduced.
Abstract: In this paper, we examine the role of polarimetry in synthetic aperture radar (SAR) interferometry. We first propose a general formulation for vector wave interferometry that includes conventional scalar interferometry as a special case. Then, we show how polarimetric basis transformations can be introduced into SAR interferometry and applied to form interferograms between all possible linear combinations of polarization states. This allows us to reveal the strong polarization dependency of the interferometric coherence. We then solve the coherence optimization problem involving maximization of interferometric coherence and formulate a new coherent decomposition for polarimetric SAR interferometry that allows the separation of the effective phase centers of different scattering mechanisms. A simplified stochastic scattering model for an elevated forest canopy is introduced to demonstrate the effectiveness of the proposed algorithms. In this way, we demonstrate the importance of wave polarization for the physical interpretation of SAR interferograms. We investigate the potential of polarimetric SAR interferometry using results from the evaluation of fully polarimetric interferometric shuttle imaging radar (SIR)-C/X-SAR data collected during October 8-9, 1994, over the SE Baikal Lake Selenga delta region of Buriatia, Southeast Siberia, Russia.

794 citations


Journal ArticleDOI
TL;DR: It is argued that most of the alternatives for explaining social learning without invoking the cognitively complex concept of imitation can be subsumed under a single process, priming, in which input increases the activation of stored internal representations.
Abstract: To explain social learning without invoking the cognitively complex concept of imitation, many learning mechanisms have been proposed. Borrowing an idea used routinely in cognitive psychology, we argue that most of these alternatives can be subsumed under a single process, priming, in which input increases the activation of stored internal representations. Imitation itself has generally been seen as a "special faculty." This has diverted much research towards the all-or-none question of whether an animal can imitate, with disap- pointingly inconclusive results. In the great apes, however, voluntary, learned behaviour is organized hierarchically. This means that im- itation can occur at various levels, of which we single out two clearly distinct ones: the "action level," a rather detailed and linear speci- fication of sequential acts, and the "program level," a broader description of subroutine structure and the hierarchical layout of a behavioural "program." Program level imitation is a high-level, constructive mechanism, adapted for the efficient learning of complex skills and thus not evident in the simple manipulations used to test for imitation in the laboratory. As examples, we describe the food- preparation techniques of wild mountain gorillas and the imitative behaviour of orangutans undergoing "rehabilitation" to the wild. Rep- resenting and manipulating relations between objects seems to be one basic building block in their hierarchical programs. There is evi- dence that great apes suffer from a stricter capacity limit than humans in the hierarchical depth of planning. We re-interpret some chimpanzee behaviour previously described as "emulation" and suggest that all great apes may be able to imitate at the program level. Action level imitation is seldom observed in great ape skill learning, and may have a largely social role, even in humans.

756 citations


Journal ArticleDOI
09 Apr 1998-Nature
TL;DR: Sc scalp-recorded event-related brain potentials are used to identify neural activity associated with implicit and explicit memory during the performance of a recognition memory task and show that when task and memory contamination effects are eliminated, the neural correlates of explicit and implicit memory differ qualitatively.
Abstract: One presentation of a word to a subject is enough to change the way in which the word is processed subsequently, even when there is no conscious (explicit) memory of the original presentation. This phenomenon is known as implicit memory. The neural correlates of implicit memory have been studied previously, but they have never been compared with the correlates of explicit memory while holding task conditions constant or while using a procedure that ensured that the neural correlates were not 'contaminated' by explicit memory. Here we use scalp-recorded event-related brain potentials to identify neural activity associated with implicit and explicit memory during the performance of a recognition memory task. Relative to new words, recently studied words produced activity in three neuroanatomically and functionally dissociable neural populations. One of these populations was activated whether or not the word was consciously recognized, and its activity therefore represents a neural correlate of implicit memory. Thus, when task and memory contamination effects are eliminated, the neural correlates of explicit and implicit memory differ qualitatively.

735 citations


Journal ArticleDOI
TL;DR: Key features of the histologic phenotypes of breast cancers in carriers of mutant BRCA1 and BRCa2 genes are identified and this information may improve the classification of breast cancer in individuals with a family history of the disease and may ultimately aid in the clinical management of patients.
Abstract: BACKGROUND: We have previously demonstrated that breast cancers associated with inherited BRCA1 and BRCA2 gene mutations differ from each other in their histopathologic appearances and that each of these types differs from breast cancers in patients unselected for family history (i.e., sporadic cancers). We have now conducted a more detailed examination of cytologic and architectural features of these tumors. METHODS: Specimens of tumor tissue (5-microm-thick sections) were examined independently by two pathologists, who were unaware of the case or control subject status, for the presence of cell mitosis, lymphocytic infiltration, continuous pushing margins, and solid sheets of cancer cells; cell nuclei, cell nucleoli, cell necrosis, and cell borders were also evaluated. The resulting data were combined with previously available information on tumor type and tumor grade and further evaluated by multifactorial analysis. All statistical tests are two-sided. RESULTS: Cancers associated with BRCA1 mutations exhibited higher mitotic counts (P = .001), a greater proportion of the tumor with a continuous pushing margin (P<.0001), and more lymphocytic infiltration (P = .002) than sporadic (i.e., control) cancers. Cancers associated with BRCA2 mutations exhibited a higher score for tubule formation (fewer tubules) (P = .0002), a higher proportion of the tumor perimeter with a continuous pushing margin (P<.0001), and a lower mitotic count (P = .003) than control cancers. CONCLUSIONS: Our study has identified key features of the histologic phenotypes of breast cancers in carriers of mutant BRCA1 and BRCA2 genes. This information may improve the classification of breast cancers in individuals with a family history of the disease and may ultimately aid in the clinical management of patients.

679 citations


Journal ArticleDOI
01 Jul 1998-Neuron
TL;DR: Findings support the idea that GFRalpha1 and the transmembrane tyrosine kinase Ret are both necessary receptor components for GDNF in the developing kidney and nervous system, and that GDNF and neurturin can mediate some of their activities through a second receptor.

Journal ArticleDOI
TL;DR: Novel, quantitative approaches to the interpretation of abundance indices from which reliable inferences about conservation status can be made are described, revealing critical periods during which populations are likely to have been affected by environmental change.
Abstract: 1. Widespread declines in the populations of many British farmland birds have occurred since the early 1970s. We must understand the causes of these declines tomake recommendations about conservation and agricultural management, andthis can be approached by investigating the relationships, across species, betweenabundance and agricultural change. We describe novel, quantitative approaches to the interpretation of abundance indices from which reliable inferences about conservation status can be made. 2. We calculated farmland Common Birds Census indices for 42 species, smoothed the series to reveal underlying trends and estimated confidence intervals for the changes in abundance. 3. Between 1968 and 1995, the abundance of 12 species declined significantly andthat of 14 species increased. 4. Specialization was the only significant determinant of changes in abundance (of 10 tests against species characteristics): 13 farmland specialists declined, on average, by 30%, whilst 29 more generalist species underwent an average increase of 23%, confirming that farmland birds should engender conservation concern. 5. Smoothed abundance curves, transformed to emphasize trend direction and timing, were then compared quantitatively to identify whether groups of species had shared common trends. 6. Species tended not to be strongly grouped, but small groups of species with common trends were identified. Similarities in ecology among grouped species clarify the possible environmental causes of their population trends, indicating future research priorities. 7. The groups identified included: one group consisting of three thrush species Turdus and the skylark Alauda arvensis L. which all declined from the mid-1970s after being stable previously; one group comprising three trans-Saharan migrant warblers (Sylvidae), whose abundance fell in the early 1970s and later increased; and a diverse group of six smoothly increasing species. 8. Turning points were identified as where each species’ population trend turned significantly, revealing critical periods during which populations are likely to have been affected by environmental change. 9. Three collections of downward turning points were found, including one in the mid-1970s when many farmland bird declines began. Four other periods each included many upturns. The groups of turning points should facilitate the identification of environmental changes which have had widespread effects. Management prescriptions can then be designed to reverse or to mirror such key changes and thereby focus conservation effort effectively.

Journal ArticleDOI
TL;DR: Signature whistle copying was rare and did not initiate reunions or specific vocal responses, which strongly support the hypothesis that signature whistles are used to maintain group cohesion.

Journal ArticleDOI
TL;DR: It is suggested that the low levels of variability observed in endangered populations are more likely to result from a combination of publication biases, which tend to inflate the level of variability which is considered 'normal', and inbreeding effects, which may hasten loss of variability due to drift.
Abstract: Genetic variability is the clay of evolution, providing the base material on which adaptation and speciation depend. It is often assumed that most interspecific differences in variability are due p...

Journal ArticleDOI
01 Dec 1998-Geology
TL;DR: In this article, a cladistic analysis of geologic and geochemical characters of 12 Neoproterozoic glacial deposits identifies two distinct groups that are found in a consistent stratigraphic order whenever two glacial units occur within a single succession.
Abstract: A thick Neoproterozoic carbonate and glaciogenic succession of the southern Congo craton has yielded δ 13 C and 87 Sr/ 86 Sr records through the later Cryogenian (ca. 750–600 Ma) and earlier part of the Terminal Proterozoic (ca. 600–570 Ma). Sizeable negative δ 13 C excursions (to less than–5‰) occur above each of two glacial intervals and the 87 Sr/ 86 Sr values of marine carbonates shift from ∼0.7072 to ∼0.7079 at the upper glacial level. These geochemical constraints provide a Marinoan (younger Varanger) age for the upper glacial interval, previously regarded as a second phase of the Sturtian glaciation. The δ 13 C record from the Congo craton is therefore incompatible with recent global δ 13 C syntheses that have identified four or more separate ice ages during the Neoproterozoic. A cladistic analysis of geologic and geochemical characters of 12 Neoproterozoic glacial deposits identifies two distinct groups that are found in a consistent stratigraphic order whenever two glacial units occur within a single succession. We use δ 13 C and 87 Sr/ 86 Sr records from the Congo craton and other key successions to test the null hypothesis that there were only two global glaciations (Sturtian and Marinoan) during the Neoproterozoic. Placing the GSSP (global stratotype section and point) for the base of the Terminal Proterozoic within or just above a cap carbonate of the younger (Marinoan) glaciogenic succession would confine all known Neoproterozoic glaciations to the Cryogenian. The rapid shift in marine 87 Sr/ 86 Sr to more radiogenic values during the Marinoan glaciation is opposite that predicted by the snowball Earth scenario which calls for continental runoff to cease during glaciation, resulting in a shift to less radiogenic values.

Journal ArticleDOI
TL;DR: Experiments monitoring the egg and larval production of captive northwest Atlantic cod Gadus morhua indicated that first-timespawners perform poorly compared to second-time spawners, and larvae are less likely to hatch in environmental conditions favorable for survival.
Abstract: Experiments monitoring the egg and larval production of captive northwest Atlantic cod Gadus morhua indicated that first-time spawners perform poorly compared to second-time spawners. They breed for a shorter period, produce fewer egg batches, exhibit lower fecundity, and produce smaller eggs with lower fertilization and hatching rates; moreover, their larvae are less likely to hatch in environmental conditions favorable for survival. Batch-average egg diameters of first-time spawners underwent a continuous rapid decline between initial and terminal batches, whereas second-time spawners commonly exhibited a parabolic curve (slight increase followed by a decrease). Seasonal composite hatching rates of all eggs spawned by first- and second-time spawners were 13 and 62%, respectively. Larval production per maternal gram was an order of magnitude greater for second-time than for first-time spawners (200 versus 20 larvae/g). Batch-average egg diameter declined 11% and larval dry weight declined 29% fr...

Journal ArticleDOI
01 May 1998-Pain
TL;DR: It can be unhelpful for pain classification systems to combine surgery and trauma in a single category, and studies are needed to identify the operative procedures associated with the development of pain so that preventive measures can be implemented.
Abstract: Surgery and trauma are recognised as important causes of chronic pain, although their overall contribution has not been systematically studied. This paper reports on the contribution of surgery and trauma to chronic pain among 5130 patients attending 10 outpatient clinics located throughout North Britain. Surgery contributed to pain in 22.5% of patients, and was particularly associated with the development of pain in the abdomen and with anal, perineal and genital pain. Trauma was a cause of pain in 18.7% of patients, and was most common in pain in the upper limb, the spine and the lower limb. Patients with chronic pain associated with trauma are on average younger than those with chronic post-surgical pain. Further, and unusually for pain conditions, the trauma patients show an excess of males over females. These findings indicate that it can be unhelpful for pain classification systems to combine surgery and trauma in a single category. The results also point to areas for potentially fruitful research into the aetiology of chronic pain. In particular, studies are needed to identify the operative procedures associated with the development of pain so that preventive measures can be implemented.

Journal ArticleDOI
TL;DR: It is proposed that the heat shock protein family can be classified as a class of anti-apoptotic genes, in addition to the Bcl-2 and inhibitor of apoptosis protein families of genes, and that HSP72 acts downstream of SAPK/JNK.

Journal ArticleDOI
TL;DR: In this paper, the authors used cross-correlation analysis to derive the sizes of the broad Hβ-emitting regions based on emission-line time delays, or lags.
Abstract: We present the light curves obtained during an 8 yr program of optical spectroscopic monitoring of nine Seyfert 1 galaxies: 3C 120, Akn 120, Mrk 79, Mrk 110, Mrk 335, Mrk 509, Mrk 590, Mrk 704, and Mrk 817. All objects show significant variability in both the continuum and emission-line fluxes. We use cross-correlation analysis to derive the sizes of the broad Hβ-emitting regions based on emission-line time delays, or lags. We successfully measure time delays for eight of the nine sources and find values ranging from about 2 weeks to a little over 2 months. Combining the measured lags and widths of the variable parts of the emission lines allows us to make virial mass estimates for the active nucleus in each galaxy. The virial masses are in the range 107-108 M☉.

Journal ArticleDOI
TL;DR: A structure-based alignment of TNFR family members indicates that the extracellular domains are constructed primarily of two small polypeptide modules, which play distinctive structural roles in the architecture of the domains.

Journal ArticleDOI
TL;DR: In this paper, the rotational frequency shift of a light beam in classical terms and measure it using a mm-wave source is explained using a rotational Doppler shift model, which is equivalent to the momentum per photon multiplied by the translational velocity.
Abstract: We explain the rotational frequency shift of a light beam in classical terms and measure it using a mm-wave source. The shift is equal to the total angular momentum per photon multiplied by the angular velocity between the source and observer. This is analogous to the translational Doppler shift, which is equal to the momentum per photon multiplied by the translational velocity. We show that the shifts due to the spin and orbital angular momentum components of the light beam act in an additive way.

Journal ArticleDOI
TL;DR: The prevalence of reports of facilitatory, rather than neutral or inhibitory, effects amongst the various species investigated is highlighted and the possible role(s) of larva‐larva interactions, cue perception distances, hierarchical effects and whether or not biofilm cues are surface‐bo... is considered.
Abstract: The methodologies applied in laboratory and field studies of the effects of biofilm cues on marine invertebrate larval settlement on hard substrata are briefly reviewed and some of the general problems (such as experimental repeatability, handling effects) that may be encountered, and the ecological representativeness of the species utilized are discussed. The review focuses also on the range of bioassay approaches and highlights the wide range of larval densities, substrata and biofilm sources that have been variously applied. It is important to consider all of these features in any attempt at formulating general principles and trends relating to larval settlement responses in natural assemblages. This review also highlights the prevalence of reports of facilitatory, rather than neutral or inhibitory, effects amongst the various species investigated and considers the possible role(s) of larva‐larva interactions, cue perception distances, hierarchical effects and whether or not biofilm cues are surface‐bo...

Journal ArticleDOI
TL;DR: Metal-free radical chain sequences based around cyclohexadiene derivatives are being developed, and tetrathiafulvalenes mimic metals and allow a crossover from homolytic to ionic chemistry.
Abstract: An urgent search is being made for generic reagents that promote free radical synthetic transformations as means of banishing the toxic threat of organotin hydrides. Although second-generation tin reagents are beguiling, organosilanes and a range of thiocarbonyl compounds are more intrinsically benign. Metal-free radical chain sequences based around cyclohexadiene derivatives are being developed (see reaction scheme), and tetrathiafulvalenes mimic metals and allow a crossover from homolytic to ionic chemistry. Z=alkene.

Journal ArticleDOI
TL;DR: In this article, a computer-generated hologram is used for the production of high-order multiringed Laguerre-Gaussian modes with specific azimuthal and radial indices.
Abstract: A computer-generated hologram is used for the production of high-order multiringed Laguerre–Gaussian modes. These holograms differ from those previously reported in that they have an additional circular discontinuity. The holograms are used in transmission and are designed to convert the fundamental Hermite–Gaussian laser mode into a Laguerre–Gaussian mode with specific azimuthal and radial indices. The optical efficiency exceeds 40% with a radial mode purity of approximately 80%.

Book
08 Oct 1998
TL;DR: The culture of the countryside 7. Consuming Rome 8. Keeping faith? 9. Roman power and the Gauls 10. Being Roman in Gaul 11. Mapping cultural change.
Abstract: 1. On Romanization 2. Roman power and the Gauls 3. The civilising ethos 4. Mapping cultural change 5. Urbanising the Gauls 6. The culture of the countryside 7. Consuming Rome 8. Keeping faith? 9. Being Roman in Gaul.

Journal ArticleDOI
TL;DR: Evaluation strategies are introduced: lazy higher-order functions that control the parallel evaluation of non-strict functional languages that can be used to model a wide range of commonly used programming paradigms, including divide-and-conquer parallelism, pipeline Parallelism, producer/ consumer parallelism and data-oriented parallelism.
Abstract: The process of writing large parallel programs is complicated by the need to specify both the parallel behaviour of the program and the algorithm that is to be used to compute its result. This paper introduces evaluation strategies: lazy higher-order functions that control the parallel evaluation of non-strict functional languages. Using evaluation strategies, it is possible to achieve a clean separation between algorithmic and behavioural code. The result is enhanced clarity and shorter parallel programs. Evaluation strategies are a very general concept: this paper shows how they can be used to model a wide range of commonly used programming paradigms, including divide-and-conquer parallelism, pipeline parallelism, producer/consumer parallelism, and data-oriented parallelism. Because they are based on unrestricted higher-order functions, they can also capture irregular parallel structures. Evaluation strategies are not just of theoretical interest: they have evolved out of our experience in parallelising several large-scale parallel applications, where they have proved invaluable in helping to manage the complexities of parallel behaviour. Some of these applications are described in detail here. The largest application we have studied to date, Lolita, is a 40,000 line natural language engineering system. Initial results show that for these programs we can achieve acceptable parallel performance, for relatively little programming effort.

Journal ArticleDOI
TL;DR: Imitation in chimpanzees may have some power to produce cultural convergence, counter to the supposition that individual learning processes corrupt copied actions.
Abstract: Imitation was studied experimentally by allowing chimpanzees (Pan troglodytes) to observe alternative patterns of actions for opening a specially designed "artificial fruit." Like problematic foods primates deal with naturally, with the test fruit several defenses had to be removed to gain access to an edible core, but the sequential order and method of defense removal could be systematically varied. Each subject repeatedly observed 1 of 2 alternative techniques for removing each defense and 1 of 2 alternative sequential patterns of defense removal. Imitation of sequential organization emerged after repeated cycles of demonstration and attempts at opening the fruit. Imitation in chimpanzees may thus have some power to produce cultural convergence, counter to the supposition that individual learning processes corrupt copied actions. Imitation of sequential organization was accompanied by imitation of some aspects of the techniques that made up the sequence.

Journal ArticleDOI
TL;DR: The results support the conclusion that increasing the volume and surface density of mitochondrial clusters is the primary mechanism for enhancing the aerobic capacity of muscle in cold-water fish.
Abstract: The abundance, distribution and oxidative capacities of mitochondria have been investigated in the red pectoral fin adductor muscles of fish (Order Perciformes) that use a predominantly labriform style of swimming. Mediterranean Sea species from the families Labridae, Serranidae, Sparidae and Antarctic Nototheniidae and non-Antarctic Nototheniidae and Channichthyidae were studied. Sub-Antarctic species from the Beagle Channel, Tierra del Fuego, included the pelagic haemoglobin-less icefish (Champsocephalus esox) and the robalo (Eleginops maclovinus), which occurs as far north as 35 degrees S. In Champsocephalus esox, the mitochondrial volume density of red muscle was 0.51 and mitochondrial cristae surface density (43. 9 microm2 microm-3) was higher than reported for Antarctic icefishes. In the red-blooded, active pelagic or semi-pelagic species, mitochondrial volume density was within the range 0.27-0.33 regardless of habitat temperature. Amongst less active demersal species, mitochondrial volume density ranged from 0.29-0.33 in polar species to 0.08-0.13 in Mediterranean species. In Antarctic species and Champsocephalus esox, myofibrils occurred in ribbons or clusters one fibril thick entirely surrounded by mitochondria. The volume density of intracellular lipid droplets was not correlated with activity patterns or habitat temperature. In a comparison of Eleginops maclovinus caught in summer (approximately 10 degrees C) and winter (approximately 4 degrees C), mitochondrial volume density did not differ, whereas the surface density of mitochondrial clusters was higher in summer fish. The temperature-dependence of the state 3 respiration rate of isolated mitochondria with pyruvate as substrate was described by a single quadratic relationship for all species, indicating no significant up-regulation of the maximum rate of oxygen uptake per milligram mitochondrial protein in Antarctic species. Our results support the conclusion that increasing the volume and surface density of mitochondrial clusters is the primary mechanism for enhancing the aerobic capacity of muscle in cold-water fish.

Journal ArticleDOI
TL;DR: In this article, the authors observed the rotational frequency shift of a mm-wave beam with an orbital angular momentum of $l ∆ ∆ + ∆ per photon, when the beam is rotated at an angular frequency ∆+ ∆−Omega, and showed that this shift, and those found in a number of experiments on the rotation of circularly polarized beams, are special cases of the rotation frequency shift recently predicted by Bialynicki-Birula.
Abstract: We observe the frequency shift, $l\ensuremath{\Omega}$, imparted to a mm-wave beam with an orbital angular momentum of $l\ensuremath{\Elzxh}$ per photon, when the beam is rotated at angular frequency $\ensuremath{\Omega}$. We show that this shift, and those found in a number of experiments on the rotation of circularly polarized beams, are special cases of the rotational frequency shift recently predicted by Bialynicki-Birula and Bialynicka-Birula. The measurement also explicitly confirms a theoretical prediction by Nienhuis.

Journal ArticleDOI
TL;DR: A detailed survey of attitudes towards safety at the Sellafield site of British Nuclear Fuels in Cumbria is described in this paper, where focus groups were held to elicit safety-relevant beliefs, attitudes and values, and the material was incorporated into a 172-item questionnaire administered as part of the monthly team briefings.
Abstract: This paper describes a detailed survey of attitudes towards safety at the Sellafield site of British Nuclear Fuels in Cumbria. Focus groups were held to elicit safety-relevant beliefs, attitudes and values, and the material was incorporated into a 172-item questionnaire administered as part of the monthly team briefings, and preceded by an explanatory video. Data were collected in this survey from 5296 participants. The questions covered nine domains of safety, i.e. safety procedures, risks, job satisfaction, safety rules, participation, training, control, and design of plant. Each domain was analysed by principal components analysis and 38 factors were extracted. The 19 accounting for most variance were analysed. Factor scores were validated against reported number of lost-time accidents and most discriminated at high levels of significance. Various methods for analysing the data are described. Results were compared with a ‘generic’ analysis of the whole data set, which produced 42 factors. Thes...