48 research outputs found
A planner for All-Terrain Vehicles on unknown rough terrains based on the MPC paradigm and D*-like algorithm
A novel conceptual design of a planner for a mobile vehicle, operating on poorly traversable unknown rough terrains, is discussed. Finding a way to include a vehicle model into the planning stage, while coping with unknown or partially known terrains, is a challenging and rarely addressed optimization setup. The main advantages of a possible solution of such a problem would be twofold. First, the planner would give trajectories which are feasible to follow by the vehicle, which is not the case in many other state of the art planning algorithms especially for large vehicle speeds. Second, those trajectories would be the optimal ones in accordance to the current vehicle states and knowledge on its environment.
We propose a solution based on an MPC planning paradigm, wherein the planner solves a constrained optimal control problem at each time instant using the current knowledge on the terrain, which is caught appropriately by an objective function. Solving an optimal control problem allows for the vehicle model being included into the planning stage, while the repeated optimization allows for taking continuously into account new terrain information. To deal with the information given beyond the sensor range and to guarantee reaching a given goal position, we have adopted a Dā-like algorithm for rough terrains being used as a cost-to-go term within the optimization setup
Spatially-resolved potential measurement with ion crystals
We present a method to measure potentials over an extended region using
one-dimensional ion crystals in a radio frequency (RF) ion trap. The
equilibrium spacings of the ions within the crystal allow the determination of
the external forces acting at each point. From this the overall potential, and
also potentials due to specific trap features, are calculated. The method can
be used to probe potentials near proximal objects in real time, and can be
generalized to higher dimensions.Comment: 7 pages (double spaced), 3 figure
Design and Test of a Forward Neutron Calorimeter for the ZEUS Experiment
A lead scintillator sandwich sampling calorimeter has been installed in the
HERA tunnel 105.6 m from the central ZEUS detector in the proton beam
direction. It is designed to measure the energy and scattering angle of
neutrons produced in charge exchange ep collisions. Before installation the
calorimeter was tested and calibrated in the H6 beam at CERN where 120 GeV
electrons, muons, pions and protons were made incident on the calorimeter. In
addition, the spectrum of fast neutrons from charge exchange proton-lucite
collisions was measured. The design and construction of the calorimeter is
described, and the results of the CERN test reported. Special attention is paid
to the measurement of shower position, shower width, and the separation of
electromagnetic showers from hadronic showers. The overall energy scale as
determined from the energy spectrum of charge exchange neutrons is compared to
that obtained from direct beam hadrons.Comment: 45 pages, 22 Encapsulated Postscript figures, submitted to Nuclear
Instruments and Method
Challenges and opportunities for ELSI early career researchers
Background: Over the past 25 years, there has been growing recognition of the importance of studying the Ethical, Legal and Social Implications (ELSI) of genetic and genomic research. A large investment into ELSI research from the National Institutes of Health (NIH) Human Genomic Project budget in 1990 stimulated the growth of this emerging field; ELSI research has continued to develop and is starting to emerge as a field in its own right. The evolving subject matter of ELSI research continues to raise new research questions as well as prompt re-evaluation of earlier work and a growing number of scholars working in this area now identify themselves as ELSI scholars rather than with a particular discipline.
Main text: Due to the international and interdisciplinary nature of ELSI research, scholars can often find themselves isolated from disciplinary or regionally situated support structures. We conducted a workshop with Early Career Researchers (ECRs) in Oxford, UK, and this paper discusses some of the particular challenges that were highlighted. While ELSI ECRs may face many of the universal challenges faced by ECRs, we argue that a number of challenges are either unique or exacerbated in the case of ELSI ECRs and discuss some of the reasons as to why this may be the case. We identify some of the most pressing issues for ELSI ECRs as: interdisciplinary angst and expertise, isolation from traditional support structures, limited resources and funding opportunities, and uncertainty regarding how research contributions will be measured. We discuss the potential opportunity to use web 2.0 technologies to transform academic support structures and address some of the challenges faced by ELSI ECRs, by helping to facilitate mentoring and support, access to resources and new accreditation metrics.
Conclusion: As our field develops it is crucial for the ELSI community to continue looking forward to identify how emerging digital solutions can be used to facilitate the international and interdisciplinary research we perform, and to offer support for those embarking on, progressing through, and transitioning into an ELSI research career
Tooth Crown Morphology in Turner and Klinefelter Syndrome Individuals from a Croatian Sample
Svrha: Turnerov sindrom (TS) i Klinefelterov sindrom (KS) dvije su najÄeÅ”Äe aneuploidije kromosoma X i svaka je povezana sa sustavnim poremeÄajima u rastu i razvoju. Istraživan je utjecaj tih sindroma na morfologiju krune zuba na uzorku osoba iz Hrvatske. Ispitanici i postupci: Uzorak je sadržavao 57 osoba s TS-om, 37 s KS-om i 88 u kontrolnom uzorku. Morfologija kruna zuba vrjednovana je prema Turner-Scottovu dentoantropoloÅ”kom sustavu. Rezultati: Lopatasti sjekutiÄi i hipokonus bili su znaÄajno drukÄiji u osoba s TS-om u odnosu prema kontroli i osobama s KS-om. Osobe s TS-om pokazuju niže stupnjeve ekspresije negoli one u drugim skupinama. Nadalje, znaÄajno je razliÄit bio broj lingvalnih kvržica na mandibularnim pretkutnjacima, hipokonulid na mandibularnom drugom kutnjaku i kvržica 7 na mandibularnom prvom kutnjaku, premda uparena usporedba nije rasvijetlila te razlike. Tuberculum dentale, distalni akcesorni greben oÄnjaka i Carabellijevo obilježje , bili su izraženi sliÄno kao u kontroli. Osobe s KS-om nisu se znaÄajno razlikovale od kontrolnog uzorka ni u jednom obilježju, Å”to je možda povezano s veliÄinom uzorka. ZakljuÄak: U dosadaÅ”njim istraživanjimaautori pretpostavljaju da gubitak kromosoma X reducirajuÄe utjeÄe na morfologiju krune zuba, Å”to je
potvrÄeno u ovom istraživanju. Osobe s TS-om pokazuju opÄe pojednostavljenu morfologiju zuba u usporedbi s kontrolnim uzorkom, premda su neka obilježja izražena podjednako kao u kontrolnom uzorku. UÄinci KS-a manje su jasni. Premda se u dosadaÅ”njim istraživanjima sugerira da prekobrojni kromosom X poveÄava dimenzije zubne krune, u ovom istraživanju nije naÄen znaÄajan uÄinak na morfologiju krune zuba.Objective: Turner syndrome (TS) and Klinefelter syndrome (KS) represent the two most common X chromosome aneuploidies, each associated with systemic disruptions to growth and development. Effects of these conditions on tooth crown morphology are explored in a sample of Croatian individuals. Material and Methods: The sample included 57 TS, 37 KS and 88 control individuals. Dental crown morphology was scored on dental casts according to the Turner-Scott Dental Anthropology System. Results: Incisor shoveling and the hypocone were significantly different between TS individuals and both control and KS individuals. Individuals with TS exhibit lower grades of expression than either group. Furthermore, the number of lingual cusps on the mandibular premolars, the hypoconulid on the mandibular second molar, and cusp 7 on the mandibular first molar were significantly different, though pair-wise comparisons did not elucidate these differences. Tuberculum dentale, distal accessory ridge, and Carabelliās trait were expressed similarly to the control. KS individuals were not significantly different from control individuals for any trait, though this may be related to sample size. Conclusions: Previous studies suggest the loss of an X chromosome has a reducing effect on
dental crown morphology, which is confirmed in this research. TS individuals exhibit generally simpler dental morphology compared to the control sample, though some traits are expressed comparably to the control sample. The effects of KS are less clear. Though previous studies suggest that the presence of an extra X chromosome increases dental crown dimensions, there was no notable effect on crown morphology in this study