Comparison of human and humanoid robot control of upright stance

There is considerable recent interest in developing humanoid robots. An important substrate for many motor actions in both humans and biped robots is the ability to maintain a statically or dynamically stable posture. Given the success of the human design, one would expect there are lessons to be learned in formulating a postural control mechanism for robots. In this study we limit ourselves to considering the problem of maintaining upright stance. Human stance control is compared to a suggested method for robot stance control called zero moment point (ZMP) compensation. Results from experimental and modeling studies suggest there are two important subsystems that account for the low- and mid-frequency (DC to 1 Hz) dynamic characteristics of human stance control. These subsystems are (1) a “sensory integration” mechanism whereby orientation information from multiple sensory systems encoding body kinematics (i.e. position, velocity) is flexibly combined to provide an overall estimate of body orientation while allowing adjustments (sensory re-weighting) that compensate for changing environmental conditions and (2) an “effort control” mechanism that uses kinetic-related (i.e., force-related) sensory information to reduce the mean deviation of body orientation from upright. Functionally, ZMP compensation is directly analogous to how humans appear to use kinetic feedback to modify the main sensory integration feedback loop controlling body orientation. However, a flexible sensory integration mechanism is missing from robot control leaving the robot vulnerable to instability in conditions where humans are able to maintain stance. We suggest the addition of a simple form of sensory integration to improve robot stance control. We also investigate how the biological constraint of feedback time delay influences the human stance control design. The human system may serve as a guide for improved robot control, but should not be directly copied because the constraints on robot and human control are different.     

Activation Energies of Reactions Catalyzed by the Nitrate Reductase from Chlorella vulgaris

The thermal dependence of two of the reactions catalyzed bythe nitrate reductase from Chlorella vulgaris was determined.The activation energies for NADH:nitrate oxidoreductase (EC1.6.6.1 [EC] ) and NADH:Cytochrome c oxidoreductase (EC 1.6.99.3 [EC] )are 42.1 kJ?mol^–1 and 21.5 kJ?mol^–1, respectively.Since the thermal dependency of the two enzymes is different,ratios of the activities will vary with temperature. The importanceof both rigorous thermal control during nitrate reductase assaysas well as the need to specify the temperature at which theratio of activities for the enzyme are clearly established. ¹Present Address: Cropping Systems Research Laboratory, USDA-ARS,Route 3, Box 215, Lubbock, TX 79401, U.S.A. (Received November 25, 1987; Accepted March 2, 1988)     

Salinity induced changes in the reproductive physiology of wheat plants

The effect of salinity on reproductive physiology of wheat wasinvestigated. One set of wheat plants was subjected to increasingsalt levels up to a certain concentration, whereas another setwas given the same concentration in a single application. Theformer was called "gradual" and latter "shock" treatment. Theireffects on pollen viability, germination and activity of starchsynthetase were studied. Gradual treatment seemed to reducethe toxic effects of salts on the viability of pollen grainsand their germination. Seeds obtained from the two sets weregerminated in the same salinities in which their plants hadbeen growing, and the results were compared with those of seedsobtained from control plants growing in a non-saline medium.The seeds of plants from the gradual treatment were better suitedfor germination on a saline medium than those from the shocktreatment or the control group. Salt treatment also increasedthe activity of starch synthetase at the midmilky stage in developinggrains. This phenomenon was considered essential for synthesisof starch in a saline environment. The increase in Na⁺ and Cl^– and decrease in K⁺ contentsof wheat grains in both treatments suggest that the effect ofsalinity on the physiological phenomenon studied is due to changesin the ionic content of the plants. ¹ In partial fulfilment of a Ph.D. degree from the Universityof Karachi, Pakistan. ² Professor of Botany, Director of Research Projects, Head,Plant Physiology Section, University of Karachi, Pakistan. (Received July 11, 1977; )     

Glycine-serine transformation in the photosynthetic bacterium Chromatium vinosum

The metabolic transformation of glycine into serine in the photosyntheticbacterium Chromatium vinosum was accompanied by the evolutionof CO₂ due to decarboxylation of glycine. Isonicotinylhydrazideinhibited both ¹⁴CO₂ evolution and the formation of ¹⁴C-serinefrom ¹⁴C-glycine. The results indicate that a glycine-serinetransformation reaction takes place which is analogous to thatoccurring in green leaf tissues. Glycine may be metabolisedthrough serine by this reaction. The light stimulation of ¹⁴CO₂evolution and ¹⁴C-serine formation from 14C-glycine by the Chromatiumcells are judged to be results of the light-induced enhancementof ¹⁴C-glycine uptake by the bacterial cells. ¹This is paper 53 in the series "Structure and Function of ChloroplastProteins" and paper 7 of the series "Biosynthetic Mechanismof Glycolate in Chromatium". Paper 6 of the latter series isRef. 3 by Asami and Akazawa (1978). ²This study was aided by research grants from the Ministry ofEducation, Science and Culture of Japan and the Nissan ScienceFoundation (Tokyo). ³Postdoctoral Fellow (1980) of the Japan Society for the Promotionof Science. (Received May 20, 1980; )     

Emotion Attribution to a Non-Humanoid Robot in Different Social Situations

In the last few years there was an increasing interest in building companion robots that interact in a socially acceptable way with humans. In order to interact in a meaningful way a robot has to convey intentionality and emotions of some sort in order to increase believability. We suggest that human-robot interaction should be considered as a specific form of inter-specific interaction and that human–animal interaction can provide a useful biological model for designing social robots. Dogs can provide a promising biological model since during the domestication process dogs were able to adapt to the human environment and to participate in complex social interactions. In this observational study we propose to design emotionally expressive behaviour of robots using the behaviour of dogs as inspiration and to test these dog-inspired robots with humans in inter-specific context. In two experiments (wizard-of-oz scenarios) we examined humans'' ability to recognize two basic and a secondary emotion expressed by a robot. In Experiment 1 we provided our companion robot with two kinds of emotional behaviour (“happiness” and “fear”), and studied whether people attribute the appropriate emotion to the robot, and interact with it accordingly. In Experiment 2 we investigated whether participants tend to attribute guilty behaviour to a robot in a relevant context by examining whether relying on the robot''s greeting behaviour human participants can detect if the robot transgressed a predetermined rule. Results of Experiment 1 showed that people readily attribute emotions to a social robot and interact with it in accordance with the expressed emotional behaviour. Results of Experiment 2 showed that people are able to recognize if the robot transgressed on the basis of its greeting behaviour. In summary, our findings showed that dog-inspired behaviour is a suitable medium for making people attribute emotional states to a non-humanoid robot.     

Model-based analysis of non-specific binding for background correction of high-density oligonucleotide microarrays

Motivation: High-density DNA microarrays provide us with usefultools for analyzing DNA and RNA comprehensively. However, thebackground signal caused by the non-specific binding (NSB) betweenprobe and target makes it difficult to obtain accurate measurements.To remove the background signal, there is a set of backgroundprobes on Affymetrix Exon arrays to represent the amount ofnon-specific signals, and an accurate estimation of non-specificsignals using these background probes is desirable for improvementof microarray analyses. Results: We developed a thermodynamic model of NSB on shortnucleotide microarrays in which the NSBs are modeled by duplexformation of probes and multiple hypothetical targets. We fittedthe observed signal intensities of the background probes withthose expected by the model to obtain the model parameters.As a result, we found that the presented model can improve theaccuracy of prediction of non-specific signals in comparisonwith previously proposed methods. This result will provide auseful method to correct for the background signal in oligonucleotidemicroarray analysis. Availability: The software is implemented in the R languageand can be downloaded from our website (http://www-shimizu.ist.osaka-u.ac.jp/shimizu_lab/MSNS/). Contact: furusawa{at}ist.osaka-u.ac.jp Supplementary information: Supplementary data are availableat Bioinformatics online. The authors wish it to be known that, in their opinion, thefirst two authors should be regarded as joint First Authors. Associate Editor: Trey Ideker     

Power enhancement via multivariate outlier testing with gene expression arrays

Motivation: As the use of microarrays in human studies continuesto increase, stringent quality assurance is necessary to ensureaccurate experimental interpretation. We present a formal approachfor microarray quality assessment that is based on dimensionreduction of established measures of signal and noise componentsof expression followed by parametric multivariate outlier testing. Results: We applied our approach to several data resources.First, as a negative control, we found that the Affymetrix andIllumina contributions to MAQC data were free from outliersat a nominal outlier flagging rate of =0.01. Second, we createda tunable framework for artificially corrupting intensity datafrom the Affymetrix Latin Square spike-in experiment to allowinvestigation of sensitivity and specificity of quality assurance(QA) criteria. Third, we applied the procedure to 507 Affymetrixmicroarray GeneChips processed with RNA from human peripheralblood samples. We show that exclusion of arrays by this approachsubstantially increases inferential power, or the ability todetect differential expression, in large clinical studies. Availability: http://bioconductor.org/packages/2.3/bioc/html/arrayMvout.htmland http://bioconductor.org/packages/2.3/bioc/html/affyContam.htmlaffyContam (credentials: readonly/readonly) Contact: aasare{at}immunetolerance.org; stvjc{at}channing.harvard.edu The authors wish it to be known that, in their opinion, thefirst two authors should be regarded as joint First Authors. Associate Editor: Trey Ideker     

Effect of linolenate on photosynthesis by intact spinach chloroplasts II. Influence of preillumination of leaves on the inhibition of photosynthesis by linolenate

The inhibitory effect of linolenate on intact spinach chloroplastsdepends on the level of the internal pool of metabolites. Chloroplastsfrom preilluminated leaves or chloroplasts artificially loadedwith 3-phosphoglyceric acid required higher concentrations oforthophosphate for maximal rates of CO₂ dependent O₂ evolutionthan untreated chloroplasts. The loaded chloroplasts were moresensitive to linolenate, and in the presence of linolenate theoptimal phosphate concentration was shifted toward lower values.We propose that the inhibition of photosynthesis by linolenateis due to inhibition of the "phosphate translocator". ¹ Part of this work has been published in the Book of Abstracts,4th International Congress on Photosynthesis, Reading, U.K.,1977, p. 265–266. ² This work is part of a doctoral programme carried out by L.Mv6 Akamba in this laboratory. ³ To whom reprint requests should be adressed. (Received October 14, 1978; )     

Ultraviolet-B sensitivities in Japanese lowland rice cultivars: cyclobutane pyrimidine dimer photolyase activity and gene mutation

There is a cultivar difference in the response to ultraviolet-B(UVB: 280–320 nm) in rice (Oryza sativa L.). AmongJapanese lowland rice cultivars, Sasanishiki, a leading Japaneserice cultivar, is resistant to the damaging effects of UVB whileNorin 1, a close relative, is less resistant. We found previouslythat Norin 1 was deficient in cyclobutane pyrimidine dimer (CPD)photorepair ability and suggested that the UVB sensitivity inrice depends largely on CPD photorepair ability. In order toverify that suggestion, we examined the correlation betweenUVB sensitivity and CPD photolyase activity in 17 rice cultivarsof progenitors and relatives in breeding of UV-resistant Sasanishikiand UV-sensitive Norin 1. The amino acid at position 126 ofthe deduced amino acid sequence of CPD photolyase in cultivarsincluding such as Norin 1 was found to be arginine, the CPDphotolyase activities of which were lower. The amino acid atthat position in cultivars including such as Sasanishiki wasglutamine. Furthermore, cultivars more resistant to UVB werefound to exhibit higher photolyase activities than less resistantcultivars. These results emphasize that single amino acid alterationfrom glutamine to arginine leads to a deficit of CPD photolyaseactivity and that CPD photolyase activity is one of the mainfactors determining UVB sensitivity in rice. ¹ These authors contributed equally to the paper. ² Corresponding author: E-mail, kumagai{at}ige.tohoku.ac.jp; Fax,+81-22-217-5691.     

Cytokinin effects on protein synthesis of in vitro systems of higher plants

Cytokinin, N₆-(₂-isopentenyl) adenine, stimulates the proteinsynthesis of in vitro systems prepared from tobacco pith and/orone-day-old corn shoots. The maximal stimulation was found ata cytokinin concentration of 10^–7 to 10^–6 M andwas 20 to 30% higher than the control level. ¹Herrn Prof. Dr. K. Mothes fur Vollendung seines 75. Lebensjahresgewidmet. (Received September 19, 1975; )     

PHOTOSYNTHESIS OF GLYCINE AND SERINE IN GREEN PLANTS

1. The effects of "carbonyl" reagents on the photosyntheticin-corporation of ¹⁴CO₂ into the assimilation products of tobaccoand spinach leaves were studied. The presence of "carbonyl"reagents causes an increase in the ratio of ¹⁴CO₂ incorporatedin glycine and a decrease in serine. The incorporation of ¹⁴Cfrom glycolate-1-¹⁴C and glycolaldehyde-2-¹⁴C into glycine andserine was also affected by "carbonyl" reagents, as in the caseof ¹⁴CO₂-experiment. 2. The feeding experiments of glycine-1-¹⁴C and serine-1-¹⁴Cin the presence and in the absence of "carbonyl" reagents revealedthat these reagents inhibit the conversion of glycine to serine. 3. The results obtained above, together with the effects ofthiols on ¹⁴CO₂ incorporation presented in this paper, supportthe assumption that glycine and serine are formed via glycolateand glyoxylate during photosynthesis in green plants. 4. Comparison of ¹⁴C incorporation in malate from ¹⁴CO₂, glycolate-1-¹⁴C,glycine-1-¹⁴C and serine-1-¹⁴C in the presence and in the absenceof "carbonyl" reagents suggested the occurrence of the pathwayof the malate formation via glycolate and glyoxylate, not passingthrough glycine and serine, during photosynthesis. ¹ A part of this paper was presented at the Symposium on "Nitrogenand Plant" by the Japanese Society of Plant Physiologists, inOctober, 1963 ² Present address: Radiation Center of Osaka Prefecture, Sakai,Osaka     

CHLOROPHYLL-SENSITIZED REDUCTION OF PLASTOQUINONE BY ASCORBIC ACID AND QUENCHING OF CHLOROPHYLL-FLUORESCENCE BY PLASTOQUINONE

1. Photochemical reduction of plastoquinone by ascorbic acid inethanol was sensitized with some derivatives of chlorophyll.The order of effectiveness was as follows: allomerized chlorophylla > chlorophyllin a > chlorophyll a > chlorophyll b> pheophytin a.
2. Quenching of the fluorescence of chlorophylla by plastoquinonewas observed. The quenching constant calculatedwas 71 litreper mole.

¹Contribution No. 159 from the Department of Biology, Facultyof Science, Kyushu University. Supported in part by a grant-in-aidfor Fundamental Scientific Research from the Ministry of Education. ²Present address: Biological Laboratory, General Education Department,Kyushu University, Ropponmatsu, Fukuoka. ³Present address: Biological Institute, Daiichi College of PharmaceuticalSciences, Tamagawa-machi, Takamiya, Fukuoka.     

THE INCORPORATION OF 32P ORTHOPHOSPHATE INTO THE PHOSPHOLIPIDS OF ELONGATING AVENA COLEOPTILES

Four phospholipids of Avena coleoptile tissue were identifiedas phosphatidyl inositol, phosphatidyl glycerol, phosphatidylethanolamine and phosphatidyl choline. IAA caused an increase in total uptake of ³²P and incorporationof ³²P in phospholipids. IAA also caused a shift in the proportionsof identified ³²P phospholipids. Incorporation of ³²P into phosphatidylcholine was greater while incorporation into phosphatidyl glyceroland phosphatidyl ethanolamine was less in IAA-treated tissuecompared with untreated control tissue. ¹Contribution No. 338 from the Department of Botany, PennsylvaniaState University and 3001 from the Pennsylvania AgriculturalExperiment Station. ²Present address: Juniata College, Huntingdon, Pennsylvania,U.S.A.     

Effect of abscisic acid and auxin on ribonuclease during ageing of bean endocarp tissue sections

The activity of RNase increases rapidly upon cutting sectionsof bean (Phascolus vulgaris L. var. Kentucky Wonder) endocarp,peaks within 4 to 8 hr and then declines. This rapid developmentof RNase activity is inhibited by cycloheximide. Auxin (naphthaleneaceticacid, NAA) accelerates the rate of decline of RNase. Abscisicacid (ABA) enhances the level of RNase between 4 and 24 hr,associated with a decline in RNA, and this effect of ABA isobscured in the presence of auxin. ¹ This work was supported by National Science Foundation Grant(GB-8316) to J. A. Sacher. ² On leave from Laboratorio di Radiobiochimica ed EcofisiologiaVegetale, C. N. R., Roma, (Italy), with a Fellowship supportedby North Atlantic Threaty Organization. ³ Present address: Instituto di Botanica, Universita di Ban,Bari, 70126, Italy. (Received April 1, 1971; )     

Biomimetic vibrissal sensing for robots

Active vibrissal touch can be used to replace or to supplement sensory systems such as computer vision and, therefore, improve the sensory capacity of mobile robots. This paper describes how arrays of whisker-like touch sensors have been incorporated onto mobile robot platforms taking inspiration from biology for their morphology and control. There were two motivations for this work: first, to build a physical platform on which to model, and therefore test, recent neuroethological hypotheses about vibrissal touch; second, to exploit the control strategies and morphology observed in the biological analogue to maximize the quality and quantity of tactile sensory information derived from the artificial whisker array. We describe the design of a new whiskered robot, Shrewbot, endowed with a biomimetic array of individually controlled whiskers and a neuroethologically inspired whisking pattern generation mechanism. We then present results showing how the morphology of the whisker array shapes the sensory surface surrounding the robot's head, and demonstrate the impact of active touch control on the sensory information that can be acquired by the robot. We show that adopting bio-inspired, low latency motor control of the rhythmic motion of the whiskers in response to contact-induced stimuli usefully constrains the sensory range, while also maximizing the number of whisker contacts. The robot experiments also demonstrate that the sensory consequences of active touch control can be usefully investigated in biomimetic robots.     

Changes in competible IAA binding in relation to bud development in pea seedlings

An insoluble (particulate) ³H-IAA-binding system similar tothat reported by Hertel et al. (3) is described in buds frompea seedlings. The binding is competed by NAA as well as IAA.Auxin-competible binding is optimal at 25?C and pH6.5; Ca⁺²increases binding as does a 1 hr preincubation at 4?C. Releaseof apical dominance produces outgrowth and a large decreasein the NAA-competible ³H-IAA-binding activity in the axillarybuds; this correlates with a decreased ability of auxin to inhibitthe buds. Both the antiauxin triiodobenzoic acid and the cytokininbenzyladenine also compete with the bound IAA. ¹Supported in part by a Special Research Assistance Grant fromthe College of Literature, Science and the Arts, Universityof Michigan and by USPHS Grant no. ES-000634. ²Present address: Universitet u Pritini, Prirodno-matemat-facultet,38000 Pritina, Yugoslavia. (Received May 16, 1974; )     

The effect of low temperature upon the polyribosome, nucleic acid and protein content of potato leaves

Short periods of low temperature exposure, or longer periodsof cool temperature growth did not cause a decline or "run-off"of potato leaf polyribosomes. In fact, polyribosome levels werehigher in the leaves of plants grown in the cool temperatureregime. The ribosomal RNA levels were higher in cool grown leavesafter day 12 of treatment, while the protein and amino acidlevels did not exhibit a dramatic change. The results are discussedin respect to efficient plant protein synthesis in cooler climates. ¹This research was supported in part by a grant from the RockefellerFoundation. ²Scientific Journal Series Article 8745 of the Minnesota AgriculturalExperiment Station. (Received June 20, 1974; )     

Studies on chlorophyll formation in Chlorella protothecoides III. Effects of chloramphenicol, cycloheximide, and ethionine on chlorophyll formation

Effects of chloramphenicol, cycloheximide, puromycin and ethionineon the light-independent and subsequent light-dependent processesof chlorophyll formation in "glucose-bleached" cells of Chlorellaprotothecoides were studied. These substances, except puromycin,strongly suppressed different phases of chlorophyll formation.Ethionine most strongly suppressed the light-independent phaseand chloramphenicol an early, relatively short process in thelight-dependent phase of chlorophyll formation. Cycloheximideseverely suppressed all phases of chlorophyll formation. Possibleimplications of these results for the biosynthesis of chlorophyllin algal cells are discussed. ¹ Present address: National Food Research Institute, Ministryof Agriculture and Forestry, Koto-ku, Tokyo 135, Japan. ² Laboratory of Entomology, Faculty of Agriculture, TamagawaUniversity, Machida-shi, Tokyo, Japan (Received October 5, 1972; )     

CHOICE OF BIOASSAY IN ASSESSING ACTIVITY OF ENDOGENOUS GROWTH SUBSTANCES

A chloroform extract of peelings and buds of ‘Red Pontiac’potato tubers yielded chromatographic eluates that exhibitedqualitatively and quantitatively different stimulating and inhibitingresponses on four bioassays. The essentiality of selecting asatisfactory array of bioassays, coupled with a thorough extractionprocedure, is emphasized. ¹This research was supported by United States Public HealthService Grant EF-61 ²Present address: Department of Botany, Hebrew University, Jerusalem,Israel ³Present address: Department of Agronomy, University of Tokyo,Bunkyo-ku, Tokyo