Task influence of scene content selected by active vision

This thesis investigated possible features that are used to guide saccadic eye movements in specific tasks, including a visual search task, answering questions about an image, and freely viewing images. Current eyetracking technology was used to gather eye movement records of subjects as they viewed images. A classical experiment that shows the influence of task on eye movements conducted by Alfred Yarbus was replicated under natural viewing conditions. In this experiment, 17 viewers were given a set of different instructions before viewing a Russian painting. Eye movement records were compared between tasks, and it was found that the instruction a viewer is given did affect which regions of the image are fixated. Even though the viewing times in the two experiments were drastically different (3 minutes compared to ~20 seconds), the behaviors of the 17 subjects were remarkably similar to the original record published by Yarbus; regions that were \u27informative\u27 for the task were fixated. Behavior between the 17 subjects (within one task) was more similar than between the seven tasks (within one subject). In a second experiment, 23 observers performed a visual search task in images of real-world scenes. Before each trial, the subject was shown a preview image of the target. This image was either pixel-for-pixel exactly as it appeared in the image (\u27Extracted Object\u27 condition) or was a cartoon icon representation of the target (\u27Cartoon Icon\u27 condition). On average, the reaction time in finding the target in the Cartoon Icon condition was 3.0 seconds, and less than 2.5 seconds in the Extracted Object condition. This increase in reaction time was caused primarily by the viewer taking longer to initially fixate on the target. Perceptual saliency and other feature content of the images at fixated and random locations were compared to gain insight into what features the visual system was using to guide, and expedite, visual search in each of the two conditions. Several commonly used metrics were used to measure the performance of each of 18 different topographical feature maps. It was found that feature maps that weight areas according to the color and spatial characteristics of the target perform better than general low-level saliency maps, showing that the visual system can be fine-tuned according to the task. However, a general model of visual attention for search in real-world scenes cannot be created using only low-level stimulus properties

Dimension Preference And Component Selection: Alternative Measures Of Children'S Attention To Stimulus Components 1

As children grow older they show an increasing preference for classifying objects on the basis of shape rather than color. To clarify the nature of this “dimension preference,” children of ages 3½ to 6½ years were given a method of triads test of dimension preferences, followed (after a week's delay) by a component selection task (see Hale & Morgan, 1973). The most notable results were these: (a) as expected, children below and above the median age differed in frequency of shape preference, (b) for children below the median age, higher component selection test scores were observed for the preferred dimension, although all scores were considerably above chance level and (c) no age difference was found in the relative magnitudes of the component selection scores. The results suggest that a “preference” for a particular dimension does not necessarily indicate a high degree of selective attention to that dimension. Also, the age difference in children's dimension preferences may be attributable to factors unrelated to selective attention.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/108298/1/ets200834.pd

The archaeo-eukaryotic primase of plasmid pRN1 requires a helix bundle domain for faithful primer synthesis

The plasmid pRN1 encodes for a multifunctional replication protein with primase, DNA polymerase and helicase activity. The minimal region required for primase activity encompasses amino-acid residues 40–370. While the N-terminal part of that minimal region (residues 47–247) folds into the prim/pol domain and bears the active site, the structure and function of the C-terminal part (residues 248–370) is unknown. Here we show that the C-terminal part of the minimal region folds into a compact domain with six helices and is stabilized by a disulfide bond. Three helices superimpose well with the C-terminal domain of the primase of the bacterial broad host range plasmid RSF1010. Structure-based site-directed mutagenesis shows that the C-terminal helix of the helix bundle domain is required for primase activity although it is distant to the active site in the crystallized conformation. Furthermore, we identified mutants of the C-terminal domain, which are defective in template binding, dinucleotide formation and conformation change prior to DNA extension

Effect of increased quadriceps tensile stiffness on peak anterior cruciate ligament strain during a simulated pivot landing

ACL injury prevention programs often involve strengthening the knee muscles. We posit that an unrecognized benefit of such training is the associated increase in the tensile stiffness of the hypertrophied muscle. We tested the hypothesis that an increased quadriceps tensile stiffness would reduce peak anteromedial bundle (AM‐)ACL relative strain in female knees. Twelve female cadaver knees were subjected to compound impulsive two‐times body weight loads in compression, flexion, and internal tibial torque beginning at 15° flexion. Knees were equipped with modifiable custom springs to represent the nonlinear rapid stretch behavior of a normal and increased stiffness female quadriceps (i.e., 33% greater stiffness). Peak AM‐ACL relative strain was measured using an in situ transducer while muscle forces and tibiofemoral kinematics and kinetics were recorded. A 3D ADAMS™ dynamic biomechanical knee model was used in silico to interpret the experimental results which were analyzed using a repeated‐measures Wilcoxon test. Female knees exhibited a 16% reduction in peak AM‐ACL relative strain and 21% reduction in change in flexion when quadriceps tensile stiffness was increased by 33% (mean (SD) difference: 0.97% (0.65%), p  = 0.003). We conclude that increased quadriceps tensile stiffness reduces peak ACL strain during a controlled study simulating a pivot landing. © 2013 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 32:423–430, 2014.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/102663/1/jor22531.pd

Influence of grape rot on the contents of sulfur binding compounds in wine after automated optical grape sorting

In the last years, climate change has played an important role in some wine growing regions because of the increasing hazard of different kinds of bunch rot. Botrytis cinerea is the most important kind of rot on grapes. Beside sensory effects, this rot can influence the content of yeast nutrients, e.g. thiamine, in the must and thus affect the alcoholic fermentation. To get insight into the influence of Botrytis cinerea on the content of sulfur binding compounds formed during the fermentation process in wine, tons of grapes from the Mosel valley were sorted by an automated optical grape sorter, an innovative possibility of grape sorting, in 2011. Wine samples before sulfurisation of the four sorting fractions, namely control (unsorted berries), free-run (juice from opened berries), positive (healthy, intact berries) and negative (rotten berries) were analysed for the sulfur-binding compounds acetaldehyde, pyruvic acid, 2-oxoglutaric acid and for bound sulfur dioxide. The results show that acetaldehyde concentrations were not affected by rot, while pyruvic acid and 2-oxoglutaric acid levels were significantly higher in the negative fractions and lower in the positive fractions. Accordingly, bound sulfur levels were significantly higher in wines from the negative fraction. In conclusion, it could be shown that fractionation of the berries can efficiently help to reduce sulfur binding compounds in wine and thus reduce the addition of sulfur dioxide

Extinction of conservation and transitivity of weight

This study attempted to determine whether children will relinquish their belief in Piagetian concepts upon presentation of disconfirming evidence. Two age groups were tested: third- and fourth-grade, and sixth-grade. Conservation of weight and transitivity of weight were the concepts examined; the discrepant feedback consisted of three trials with either non-conservation or nontransitivity outcomes. Resistance or extinction was inferred from the subject's explanations for the outcomes, his responses on subsequent trials, and his performance on a one-month delayed posttest. Conservation subjects showed only moderate resistance by any of these measures; furthermore, there was no evidence of a developmental increase in resistance. Transitivity subjects, in contrast, were much less likely than conservers to change their judgments on either the initial or the delayed test; they also showed the expected developmental increase in resistance to extinction. The results are interpreted as indicating that Piagetian concepts may vary in the extent to which they entail feelings of logical necessity.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/33761/1/0000013.pd

Magnetic properties of the spin-1 chain compound NiCl3_3C6_6H5_5CH2_2CH2_2NH3_3

We report experimental results of the static magnetization, ESR and NMR spectroscopic measurements of the Ni-hybrid compound NiCl$_3$C$_6$H$_5$CH$_2$CH$_2$NH$_3$. In this material NiCl$_3$ octahedra are structurally arranged in chains along the crystallographic $a$-axis. According to the static susceptibility and ESR data Ni$^{2+}$ spins $S = 1$ are isotropic and are coupled antiferromagnetically (AFM) along the chain with the exchange constant $J = 25.5$ K. These are important prerequisites for the realization of the so-called Haldane spin-1 chain with the spin-singlet ground state and a quantum spin gap. However, experimental results evidence AFM order at $T_{\rm N} \approx 10$ K presumably due to small interchain couplings. Interestingly, frequency-, magnetic field-, and temperature-dependent ESR measurements, as well as the NMR data, reveal signatures which could presumably indicate an inhomogeneous ground state of co-existent mesoscopically spatially separated AFM ordered and spin-singlet state regions similar to the situation observed before in some spin-diluted Haldane magnets

Establishment and mitotic stability of an extra-chromosomal mammalian replicon

<p>Abstract</p> <p>Background</p> <p>Basic functions of the eukaryotic nucleus, like transcription and replication, are regulated in a hierarchic fashion. It is assumed that epigenetic factors influence the efficiency and precision of these processes. In order to uncouple local and long-range epigenetic features we used an extra-chromosomal replicon to study the requirements for replication and segregation and compared its behavior to that of its integrated counterpart.</p> <p>Results</p> <p>The autonomous replicon replicates in all eukaryotic cells and is stably maintained in the absence of selection but, as other extra-chromosomal replicons, its establishment is very inefficient. We now show that following establishment the vector is stably associated with nuclear compartments involved in gene expression and chromosomal domains that replicate at the onset of S-phase. While the vector stays autonomous, its association with these compartments ensures the efficiency of replication and mitotic segregation in proliferating cells.</p> <p>Conclusion</p> <p>Using this novel minimal model system we demonstrate that relevant functions of the eukaryotic nucleus are strongly influenced by higher nuclear architecture. Furthermore our findings have relevance for the rational design of episomal vectors to be used for genetic modification of cells: in order to improve such constructs with respect to efficiency elements have to be identified which ensure that such constructs reach regions of the nucleus favorable for replication and transcription.</p

Triple-q octupolar ordering in NpO_2

We report the results of resonant X-ray scattering experiments performed at the Np M_4,5 edges in NpO_2. Below T_0 = 25 K, the development of long-range order of Np electric quadrupoles is revealed by the growth of superlattice Bragg peaks. The electronic transition is not accompanied by any measurable crystallographic distortion, either internal or external, so the symmetry of the system remains cubic. The polarization and azimuthal dependence of the intensity of the resonant peaks is well reproduced assuming Templeton scattering from a triple-q longitudinal antiferroquadrupolar structure. Electric quadrupole order in NpO_2 could be driven by the ordering at T_0 of magnetic octupoles of Gamma_5 symmetry, splitting the Np ground state quartet and leading to a singlet ground state with zero dipole magnetic moment.Comment: 4 Pages, 3 Figures, submitted to Phys. Rev. Lett. v2: resubmitted after referee report

Pilot Testing Behavior Therapy for Chronic Tic Disorders in Neurology and Developmental Pediatrics Clinics

Comprehensive Behavioral Intervention for Tics (CBIT) is an efficacious treatment with limited regional availability. As neurology and pediatric clinics are often the first point of therapeutic contact for individuals with tics, the present study assessed preliminary treatment response, acceptability, and feasibility of an abbreviated version, modified for child neurology and developmental pediatrics clinics. Fourteen youth (9-17) with Tourette disorder across 2 child neurology clinics and one developmental pediatrics clinic participated in a small case series. Clinician-rated tic severity (Yale Global Tic Severity Scale) decreased from pre- to posttreatment, z = –2.0, P \u3c .05, r = –.48, as did tic-related impairment, z = –2.4, P \u3c .05, r = –.57. Five of the 9 completers (56%) were classified as treatment responders. Satisfaction ratings were high, and therapeutic alliance ratings were moderately high. Results provide guidance for refinement of this modified CBIT protocol