High-precision satellite positioning system as a new tool to study the biomechanics of human locomotion.

New Global Positioning System (GPS) receivers allow now to measure a location on earth at high frequency (5Hz) with a centimetric precision using phase differential positioning method. We studied whether such technique was accurate enough to retrieve basic parameters of human locomotion. Eight subjects walked on an athletics track at four different imposed step frequencies (70-130steps/min) plus a run at free pace. Differential carrier phase localization between a fixed base station and the mobile antenna mounted on the walking person was calculated. In parallel, a triaxial accelerometer, attached to the low back, recorded body accelerations. The different parameters were averaged for 150 consecutive steps of each run for each subject (total of 6000 steps analyzed). We observed a perfect correlation between average step duration measured by accelerometer and by GPS (r=0.9998, N=40). Two important parameters for the calculation of the external work of walking were also analyzed, namely the vertical lift of the trunk and the velocity variation per step. For an average walking speed of 4.0km/h, average vertical lift and velocity variation were, respectively, 4.8cm and 0.60km/h. The average intra-individual step-to-step variability at a constant speed, which includes GPS errors and the biological gait style variation, were found to be 24. 5% (coefficient of variation) for vertical lift and 44.5% for velocity variation. It is concluded that GPS technique can provide useful biomechanical parameters for the analysis of an unlimited number of strides in an unconstrained free-living environment.

Maximized Utility of the Global Positioning System, HR-316, 1991

This report describes a project begun in January 1989 and completed December 1990, with the primary objective of obtaining sufficiently accurate horizontal and vertical control by using Global Positioning System (GPS) for highway applications. The ISU research group studied the operations of the Ashtech GPS receiver in static, pseudo-static, kinematic, and pseudo-kinematic modes. By using the Electronic Distance Measuring Instrument (EDMI) Calibration Baseline at ISU, the GPS receiver was tested for distance measurement accuracy. It was found that GPS measurements differed from the baseline distance by about 5.3 mm. Four projects were undertaken to further evaluate and improve the horizontal as well as the vertical accuracies of the GPS receiver -- (1) The Campus Project: with all points concentrated within a one-mile radius; (2) The Des Moines Project: a typical DOT project with all the points within a five-mile radius; (3) The Iowa Project: with all points within a 100-mile radius in the state of Iowa; and (4) The Mustang Project: an extension of the Iowa project, including a typical DOT project of about 10 miles within the inner 30 mile radius of the Iowa project.

The dmf1/mid1 gene is essential for correct positioning of the division septum in fission yeast.

Little is known about the mechanisms that establish the position of the division plane in eukaryotic cells. Wild-type fission yeast cells divide by forming a septum in the middle of the cell at the end of mitosis. Dmf1 mutants complete mitosis and initiate septum formation, but the septa that form are positioned at random locations and angles in the cell, rather than in the middle. We have cloned the dmf1 gene as a suppressor of the cdc7-24 mutant. The dmf1 mutant is allelic with mid1. The gene encodes a novel protein containing a putative nuclear localization signal, and a carboxy-terminal PH domain. In wild-type cells, Dmf1p is nuclear during interphase, and relocates to form a medial ring at the cell cortex coincident with the onset of mitosis. This relocalization occurs before formation of the actin ring and is associated with increased phosphorylation of Dmf1p. The Dmf1p ring can be formed in the absence of an actin ring, but depends on some of the genes required for actin ring formation. When the septum is completed and the cells separate, Dmf1p staining is once again nuclear. These data implicate Dmf1p as an important element in assuring correct placement of the division septum in Schizosaccharomyces pombe cells.

Measurement of the mechanical power of walking by satellite positioning system (GPS).

PURPOSE: This descriptive article illustrates the application of Global Positioning System (GPS) professional receivers in the field of locomotion studies. The technological challenge was to assess the external mechanical work in outdoor walking. METHODS: Five subjects walked five times during 5 min on an athletic track at different imposed stride frequency (from 70-130 steps x min(-1)). A differential GPS system (carrier phase analysis) measured the variation of the position of the trunk at 5 Hz. A portable indirect calorimeter recorded breath-by-breath energy expenditure. RESULTS: For a walking speed of 1.05 +/- 0.11 m x s(-1), the vertical lift of the trunk (43 +/- 14 mm) induced a power of 46.0 +/- 20.4 W. The average speed variation per step (0.15 +/- 0.03 m x s(-1)) produced a kinetic power of 16.9 +/- 7.2 W. As compared with commonly admitted values, the energy exchange (recovery) between the two energy components was low (39.1 +/- 10.0%), which induced an overestimated mechanical power (38.9 +/- 18.3 W or 0.60 W x kg(-1) body mass) and a high net mechanical efficiency (26.9 +/- 5.8%). CONCLUSION: We assumed that the cause of the overestimation was an unwanted oscillation of the GPS antenna. It is concluded that GPS (in phase mode) is now able to record small body movements during human locomotion, and constitutes a promising tool for gait analysis of outdoor unrestrained walking. However, the design of the receiver and the antenna must be adapted to human experiments and a thorough validation study remains to be conducted.

Improvement of walking speed prediction by accelerometry and altimetry, validated by satellite positioning.

Activity monitors based on accelerometry are used to predict the speed and energy cost of walking at 0% slope, but not at other inclinations. Parallel measurements of body accelerations and altitude variation were studied to determine whether walking speed prediction could be improved. Fourteen subjects walked twice along a 1.3 km circuit with substantial slope variations (-17% to +17%). The parameters recorded were body acceleration using a uni-axial accelerometer, altitude variation using differential barometry, and walking speed using satellite positioning (DGPS). Linear regressions were calculated between acceleration and walking speed, and between acceleration/altitude and walking speed. These predictive models, calculated using the data from the first circuit run, were used to predict speed during the second circuit. Finally the predicted velocity was compared with the measured one. The result was that acceleration alone failed to predict speed (mean r = 0.4). Adding altitude variation improved the prediction (mean r = 0.7). With regard to the altitude/acceleration-speed relationship, substantial inter-individual variation was found. It is concluded that accelerometry, combined with altitude measurement, can assess position variations of humans provided inter-individual variation is taken into account. It is also confirmed that DGPS can be used for outdoor walking speed measurements, opening up new perspectives in the field of biomechanics.

The positioning of colectomy in the treatment of ulcerative colitis in the era of biologic therapy.

The position of surgery in the treatment of ulcerative colitis (UC) has changed in the era of biologics. Several important questions arise in determining the optimal positioning of surgery in the treatment of UC, which has long been a challenge facing gastroenterologists and surgeons. Surgery is life-saving in some patients and leads to better bowel function and better quality of life in most patients. The benefits of surgery, however, must be weighed against the potential surgical morbidity and compromised functioning that clearly can occur. The introduction of biologic therapy has added further complexity to decisions about medical management, surgery, and the relative timing of these choices. Appropriate medical management of UC may induce and maintain remission and may prevent surgery. However, medical management also carries risks of adverse effects, and recent data suggest that delay of surgery during ineffective medical therapy can increase the chances of negative surgical outcomes. To make individualized timely treatment decisions, early collaboration between gastroenterologists and surgeons is important and more data on predictors of treatment response and positive outcomes are needed. Early identification of patients who would benefit from biologic therapy or surgery is challenging.

Spanish E-Consumer Segmentation and Positioning in Virtual Supermarkets Sector

This article analyses different factors that influence the purchasing behaviour of online supermarket customers. These factors are related to both the appearance of the website as well as the processes that take place when making the purchase. Based on these analyses, the various groups of consumers with homogenous behaviour are studied and positioned according to their attitudes. The analysis also allows the quality of the service offered by this kind of establishment to be defined, as well as the main dimensions in which it develops. In the conclusions, factors which should influence the manager of an online supermarket to improve the quality of its service are given

WLAN ja logistiikka-ala

Tästä insinöörityöstä pyrittiin luomaan käytännönläheinen opas logistiikka-alan yritysten WLAN-ratkaisujen suunnittelusta ja toteutuksesta. Insinöörityössä on tiivistetty käytännös-ä parhaiksi todetut metodit ja teoreettinen tieto langattomista verkoista. Työn tarkoituk-sena oli kehittää ja parantaa yrityksen langattomien lähiverkkojen yksikön toimintaa ja luoda kattava opas yksikköön saapuville työntekijöille. Logistiikka-alalla WLAN-tekniikka on mahdollistanut varastoissa langattoman työskentelyn, joka on näkynyt nopeudessa ja kustannustehokkuudessa. Logistiset varastot ovat haasteellinen ympäristö WLAN-verkoille, mutta koko ajan kehittyvän tekniikan ansiosta varastoihin on mahdollista luoda nopea ja luotettava langaton lähiverkko. Insinöörityön teoreettisessa osiossa käsitellään muun muassa WLAN-tekniikan historiaa, standardeja ja yleisesti WLAN-tekniikkaa. Työssä tutustutaan myös WLAN-antenneihin, laitteistoihin ja tietoturvallisuuteen. Käytännön tutkimustyö toteutettiin kahden vuoden aikana WLAN-verkkojen ylläpidon, suunnittelun ja toteutuksen muodossa. Näiden vuosien aikana onnistuttiin kehittämään käytettyjä menetelmiä ja luomaan uusia lähestymistapoja, sekä toteuttamaan useita on-nistuneita WLAN-verkkoja. Työssä esitellään teoreettisen suunnittelun lisäksi kaksi kappa-letta onnistuneesti toteutuneita WLAN-ratkaisuja.

Description of a robotics-oriented relational positioning methodology

This paper presents a relational positioning methodology for flexibly and intuitively specifying offline programmed robot tasks, as well as for assisting the execution of teleoperated tasks demanding precise movements.In relational positioning, the movements of an object can be restricted totally or partially by specifying its allowed positions in terms of a set of geometric constraints. These allowed positions are found by means of a 3D sequential geometric constraint solver called PMF – Positioning Mobile with respect to Fixed. PMF exploits the fact that in a set of geometric constraints, the rotational component can often be separated from the translational one and solved independently.

The Arabidopsis PHYTOCHROME KINASE SUBSTRATE2 protein is a phototropin signaling element that regulates leaf flattening and leaf positioning.

In Arabidopsis (Arabidopsis thaliana), the blue light photoreceptor phototropins (phot1 and phot2) fine-tune the photosynthetic status of the plant by controlling several important adaptive processes in response to environmental light variations. These processes include stem and petiole phototropism (leaf positioning), leaf flattening, stomatal opening, and chloroplast movements. The PHYTOCHROME KINASE SUBSTRATE (PKS) protein family comprises four members in Arabidopsis (PKS1-PKS4). PKS1 is a novel phot1 signaling element during phototropism, as it interacts with phot1 and the important signaling element NONPHOTOTROPIC HYPOCOTYL3 (NPH3) and is required for normal phot1-mediated phototropism. In this study, we have analyzed more globally the role of three PKS members (PKS1, PKS2, and PKS4). Systematic analysis of mutants reveals that PKS2 (and to a lesser extent PKS1) act in the same subset of phototropin-controlled responses as NPH3, namely leaf flattening and positioning. PKS1, PKS2, and NPH3 coimmunoprecipitate with both phot1-green fluorescent protein and phot2-green fluorescent protein in leaf extracts. Genetic experiments position PKS2 within phot1 and phot2 pathways controlling leaf positioning and leaf flattening, respectively. NPH3 can act in both phot1 and phot2 pathways, and synergistic interactions observed between pks2 and nph3 mutants suggest complementary roles of PKS2 and NPH3 during phototropin signaling. Finally, several observations further suggest that PKS2 may regulate leaf flattening and positioning by controlling auxin homeostasis. Together with previous findings, our results indicate that the PKS proteins represent an important family of phototropin signaling proteins.

Paikka- ja tilannetiedon hyödyntäminen sovelluksissa

Erilaisten mobiiliverkkojen käytön yleistyessä nousee esiin uudenlaisia sovellusalueita, kuten esimerkiksi paikkatietoiset sovellukset. Mobiiliudesta johtuen sovellusten käyttötilanteet vaihtelevat. Käyttötilanteista voidaan kerätä tietoa ja käyttää tätä hyödyksi. Tilannetiedolla tarkoitetaan sovelluksen käyttötilanteeseen tai käyttäjään liittyvää lisätietoa. Paikka- ja tilannetietoisten sovellusten kehittäminen vaati monia ohjelmistokehitystä tukevia järjestelmiä. Tilannetiedon väljän määritelmän takia tilannetietoisten sovellusten kehitykselle ei ole vielä selkeitä toimintamalleja. Tilannetietoisten sovellusten kehitystä avustavia järjestelmiä on luotu etenkin tutkimuksessa, mutta nämä eivät ole vielä yleistyneet laajempaan käyttöön. Paikkatiedon käyttö sen sijaan on hyvinkin standardoitua, mutta paikkatieto nähdään vain osana tilannetietoa. Tässä diplomityössä toteutettiin paikka- ja tilannetiedon sovelluskehitystä tukevia järjestelmiä, joilla paikka- ja tilannetiedon hyödyntäminen sovelluksissa mahdollistettiin. WLAN - verkosta saadun paikkatiedon hyödyntämiseen toteutettiin SOAP -palvelurajapinta. Tilannetiedon hyödyntämiseksi toteutettiin MUPE -sovellusympäristöön välittäjäkomponentteja paikka-, sää- ja kuntopyörän harjoitustiedolle sekä RFID -havaintotiedoille. Näitä komponetteja käytettiin tilannetietoisten sovellusten luomiseen sekä tietoliikennetekniikan laitoksen codecamp -kursseilla, että tilannetietoisessa pelisovelluksessa. Työn tuloksena saatiin toimivia sovelluksia, ja välittäjäkomponentit sovellusten luomiseen. Työn tuloksena voidaan todeta, että ilman tilannetietoista sovelluskehitystä tukevia komponentteja, olisi tämäntyyppinen sovelluskehitys huomattavasti vaativampaa. Tukevat komponentit helpottavat sovelluskehitystä, mutta helposti myös rajaavat kehitysmahdollisuuksia.

Mobile robot localization using sonar ranging and wlan intensity maps

 Main goal of this thesis was to implement a localization system which uses sonars and WLAN intensity maps to localize an indoor mobile robot. A probabilistic localization method, Monte Carlo Localization is used in localization. Also the theory behind probabilistic localization is explained. Two main problems in mobile robotics, path tracking and global localization, are solved in this thesis. Implemented system can achieve acceptable performance in path tracking. Global localization using WLAN received signal strength information is shown to provide good results, which can be used to localize the robot accurately, but also some bad results, which are no use when trying to localize the robot to the correct place. Main goal of solving ambiguity in office like environment is achieved in many test cases.

Translation of polarity cues into asymmetric spindle positioning in "Caenorhabditis elegans"

Abstract: Asymmetric cell division is important to generate tissue diversity. The Caenorhabditis elegans embryo is well suited to study the mechanisms of asymmetric cell division. In wild type one-cell stage embryos, the spindle sets up along the anterior-posterior axis (AP). During anaphase, the spindle elongates. While the anterior spindle pole is relatively immobile, the posterior spindle pole moves towards the posterior cortex during anaphase leading to an asymmetric spindle position. As a result, the first cleavage gives rise to a large anterior blastomere and a smaller posterior one, which differs also in cell fate determinants. This posterior spindle displacement occurs in response to polarity cues set up along the AP axis by the PAR proteins and is due to imbalanced pulling forces acting on the two spindle poles, with net forces acting on the posterior spindle pole being more extensive than those at the anterior one. The project of my thesis was to characterize the involvement of two new components, gpr-1 and gpr-2, in spindle positioning. These genes encode essentially identical proteins containing a GoLoco motif characteristic of proteins interacting with α subunits of heterotrimeric G protein (Gα). In gpr-1/2(RNAi) embryos and in embryos lacking simultaneously two α subunits, goa-1 and gpa-16, (Ga(RNAi) embryos), there is a minimal posterior displacement of the spindle during anaphase, and the first division is equal. I found that the pulling forces acting on the two spindle poles is weak and equal in gpr-1/2(RNAi) and Gα (RNAi) embryos. I found that GPR-1/2 acts downstream of polarity cues for generation of pulling forces. Furthermore, I showed that GPR-1/2 distribution was enriched at the posterior cortex during metaphase whereas GOA-1 and GPA-16 were uniformly distributed at the cell cortex throughout the cell cycle. Gα subunits oscillate between GDP- and GTP-bound forms. Gα signaling is turned on by GDP/GTP exchange catalyzed by guanine nucleotide exchange factors (GEFs) and turned off by hydrolysis of GTP catalyzed by GTPase activating proteins (GAPs). A third class of proteins, the guanine dissociation inhibitors (GDIs), binds the GDP-bound form of Gα subunits and inhibits nucleotide exchange. I found that GPR-1/2 acts as a GDI for GOA-1. Taken together, my findings suggest a model in which differential activation of Gα subunits along the AP axis may translate into generation of differential pulling forces on the anterior and posterior spindle poles, and, thus, asymmetric cell division. Résumé L'embryon du nématode Caenorhabditis elegans est un modèle approprié pour étudier les mécanismes de la division asymétrique. Chez l'embryon précoce, le fuseau mitotique se forme le long de l'axe antéro-postérieur (A/P) et au centre de l'embryon, le pôle antérieur restant relativement immobile alors que le pôle postérieur du fuseau se déplace vers le cortex postérieur au cours de l'anaphase conduisant à une position excentrée du fuseau. 11 en résulte une première division qui génère un blastomère antérieur et postérieur de grande et petite taille respectivement et qui diffèrent en facteurs développementaux. Ce déplacement postérieur se produit en réponse de la polarité établie par la distribution polarisée des protéines PAR et est le résultat de la génération de forces inégales tirant sur les deux pôles du fuseau, les forces agissant sur le pôle postérieur du fuseau étant plus grandes. Le projet de ma thèse était d'identifier la fonction de deux nouveaux constituants, gpr-1 et gpr-2 dans le positionnement asymétrique du fuseau. Ces gènes codent essentiellement pour la même protéine qui contient un motif GoLoco, caractéristique des protéines interagissant avec la sous-unité alpha des protéines G hétérotrimériques. Chez l'embryon gpr-1/2(RNAi) et chez les embryons dépourvus d'activité de deux sous-unités alpha, goa-1 et gpa-16, (Gα(RNAi)), j'ai montré qu'il y avait un déplacement minimal du fuseau vers le pôle postérieur au cours de l'anaphase et la première division est symétrique en raison de forces faibles et égales agissant sur les deux pôles du fuseau. J'ai également montré que gpr-1/2 était requis en aval des signaux établissant la polarité pour générer les forces responsables du positionnement asymétrique du fuseau. De plus, j'ai montré que GPR-1/2 était enrichi au pôle postérieur lors de la métaphase alors que GOA-1 et GPA-16 étaient localisés de façon uniforme au cortex de l'embryon précoce. Gas oscillent entre une forme liée au GDP et une forme liée au GTP. La signalisation des Gas est activée par l'échange GDP/GTP qui est catalysé par des protéines GEFs. La signalisation des Gas est désactivée par l'hydrolyse du GTP qui est catalysée par des protéines GAPs. Une troisième classe de protéines, GDIs lie la forme GDP et inhibe l'échange de nucléotides. J'ai montré que GPR-1/2 agissait comme un GDI pour GOA-1. Mes résultats suggèrent un modèle dans lequel une activation différentielle des Gα le long de l'axe A/P pourrait générer des forces différentielles sur le pôle antérieur et postérieur du fuseau.

Competitive positioning of Spanish agricultural cooperatives

Cooperatives are the basis of the social economy in many agricultural sectors. The present research work investigates the management situation of the olive oil cooperatives in Catalonia. The study identifies a typology of cooperatives based on their attitudes towards to the sector. A positioning map of the different types of cooperatives is then established on the basis of their characteristics. The study concludes with important managerial aspects of olive oil cooperatives in Catalonia.