Tactile Transfer Learning and Object Recognition With a Multifingered Hand Using Morphology Specific Convolutional Neural Networks.

Multifingered robot hands can be extremely effective in physically exploring and recognizing objects, especially if they are extensively covered with distributed tactile sensors. Convolutional neural networks (CNNs) have been proven successful in processing high dimensional data, such as camera images, and are, therefore, very well suited to analyze distributed tactile information as well. However, a major challenge is to organize tactile inputs coming from different locations on the hand in a coherent structure that could leverage the computational properties of the CNN. Therefore, we introduce a morphology-specific CNN (MS-CNN), in which hierarchical convolutional layers are formed following the physical configuration of the tactile sensors on the robot. We equipped a four-fingered Allegro robot hand with several uSkin tactile sensors; overall, the hand is covered with 240 sensitive elements, each one measuring three-axis contact force. The MS-CNN layers process the tactile data hierarchically: at the level of small local clusters first, then each finger, and then the entire hand. We show experimentally that, after training, the robot hand can successfully recognize objects by a single touch, with a recognition rate of over 95%. Interestingly, the learned MS-CNN representation transfers well to novel tasks: by adding a limited amount of data about new objects, the network can recognize nine types of physical properties

Extração de DNA para análise da amelogenina em amostras fixadas em formalina, incluídas em parafina e armazenadas por 1 e 5 anos no Departamento de Patologia da Universidade Federal de São Paulo

O uso da biologia molecular em amostras fi xadas em formalina e incluídas em parafi na (FFPE) vem crescendo, e a melhoria nos métodos de obtenção do DNA para sua análise é necessária. O objetivo deste estudo foi avaliar o DNA extraído de blocos de tecidos FFPE (fígado, baço e cérebro não tumorais), obtidos de necropsia, 8 a 24 horas post mortem, utilizando três métodos de extração de DNA (kit comercial, fenolclorofórmio e Salting-Out). Foram realizadas as PCRs dos genes da actina (136pb), amelogenina humana (AMEL 212-218pb) e STRs (100-400pb) para avaliar a efi cácia do método de extração de DNA e determinar o sexo dos indivíduos. Foram utilizados 28 casos arquivados (1 e 5 anos) e 12 recentes, sendo analisadas 10 amostras de cada um dos tecidos. O kit comercial apresentou maior grau de pureza, resultados reprodutíveis e consistentes na amplifi cação por PCR nos genes da -actina e AMEL e na análise por STR. Este estudo fornece uma compreensão dos desafi os envolvendo amostras FFPE, e esclareceu novas estratégias para análises moleculares neste tipo de material

Electron Cotunneling in a Semiconductor Quantum Dot

We report transport measurements on a semiconductor quantum dot with a small number of confined electrons. In the Coulomb blockade regime, conduction is dominated by cotunneling processes. These can be either elastic or inelastic, depending on whether they leave the dot in its ground state or drive it into an excited state, respectively. We are able to discriminate between these two contributions and show that inelastic events can occur only if the applied bias exceeds the lowest excitation energy. Implications to energy-level spectroscopy are discussed.Comment: To be published in Phys. Rev. Let

Chiropractic student diagnosis and management of headache disorders: A survey examining self-perceived preparedness and clinical proficiency.

ObjectiveTo explore the self-perceived preparedness and clinical proficiency in headache diagnosis and management of Australian chiropractic students in senior years of study.MethodsAustralian chiropractic students in the 4th (n = 134) and 5th year (n = 122) of 2 chiropractic university programs were invited to participate in an online cross-sectional survey. Descriptive analyses were conducted for all variables. Post hoc analyses were performed using simple linear regression to evaluate the relationship between self-perceived preparedness and correctness of headache diagnosis and management scores.ResultsAustralian chiropractic students in senior years demonstrated moderate overall levels of self-perceived preparedness and proficiency in their ability to diagnose and manage headache disorders. Final-year students had a slightly higher self-perceived preparedness and proficiency in headache diagnosis and management compared to those students in the 4th year of study. There was no relationship between self-perceived preparedness and correctness of headache diagnosis and management for either 4th- or 5th-year chiropractic students.ConclusionOur findings suggest that there may be gaps in graduate chiropractic student confidence and proficiency in headache diagnosis and management. These findings call for further research to explore graduate chiropractic student preparedness and proficiency in the diagnosis and management of headache disorders

Clinicians' Ability to Detect a Palpable Difference in Spinal Stiffness Compared With a Mechanical Device.

OBJECTIVE: The purpose of this study was to quantify the threshold at which clinicians can detect a difference in spinal stiffness of the thoracic and lumbar spine via palpation and then determine if this detection threshold would affect a clinician's ability to identify changes in spinal stiffness as measured by an objective instrument. METHODS: In this study, the threshold at which a change in spinal stiffness was detected was quantified in 12 experienced clinicians (physical therapists and doctors of chiropractic) by changing the differential stiffness in 2 inflatable targets until the clinician could no longer identify which was stiffer. In the second part of the study, clinicians then were asked to palpate pre-identified pairs of vertebrae in an asymptomatic volunteer and to identify the stiffer of the pair (T7 and L3, T7 and L4, L3 and L4), and the biomechanical stiffness of each vertebral pair was quantified objectively by a validated instrument. RESULTS: The mean stiffness detection threshold for the clinicians was 8%. Objective measurement of the stiffness differential between vertebral pairs was 30% for T7* and L3, 20% for T7* and L4, and 10% for L3* and L4 (*denotes the stiffer of the pair). Ten of 12 clinicians correctly identified T7 as stiffer when compared with L3 and T7 as stiffer than L4. Alternatively, when the differential vertebral pair stiffness was similar to the stiffness detection threshold (~8%), clinicians were less successful in identifying the stiffer vertebra of the pair; 4 of 12 clinicians correctly identified L3 as being stiffer compared with L4. CONCLUSION: These results suggest that the physiological limits of human palpation may limit the ability of clinicians to identify small alterations in spine stiffness

Investigation of the factors influencing spinal manipulative therapy force transmission through the thorax: A cadaveric study

Abstract Spinal manipulative therapy (SMT) clinical effects are believed to be linked to its force–time profile characteristics. Previous studies have revealed that the force measured at the patient-table interface is most commonly greater than the one applied at the clinician-patient interface. The factors explaining this force amplification remains unclear. Objective To determine the difference between the force applied to a cadaveric specimen’s thoracic spine and the resulting force measured by a force-sensing table, as well as to evaluate the relationship between this difference and both the SMT force–time characteristics and the specimens’ characteristics. Methods Twenty-five SMTs with different force–time profiles were delivered by an apparatus at the T7 vertebra of nine human cadaveric specimens lying prone on a treatment table equipped with a force plate. The difference between the force applied by the apparatus and the resulting force measured by the force plate was calculated in absolute force (Fdiff) and as the percentage of the applied force (Fdiff%). Kinematics markers were inserted into T6 to T8 spinous and transverse processes to evaluate vertebral displacements during the SMT thrusts. Mixed-effects linear models were run to evaluate the variance in Fdiff and Fdiff% explained by SMT characteristics (peak force, thrust duration and force application rate), T6 to T8 relative and total displacements, and specimens’ characteristics (BMI, height, weight, kyphosis angle, thoracic thickness). Results Sixty percent of the trials showed lower force measured at the force plate than the one applied at T7. Fdiff¸ was significantly predicted (R2marginal = 0.54) by peak force, thrust duration, thoracic thickness and T6–T7 relative displacement in the z-axis (postero-anterior). Fdiff% was significantly predicted (R2marginal = 0.56) by force application rate, thoracic thickness and total T6 displacements. For both dependant variables, thoracic thickness showed the highest R2marginal out of all predictors. Conclusion Difference in force between the clinician-patient and the patient-table interfaces is influenced by SMT force–time characteristics and by thoracic thickness. How these differences in force are associated with vertebral displacements remains unclear. Although further studies are needed, clinicians should consider thorax thickness as a possible modulator of forces being transmitted through it during prone SMT procedures

Kondo effect in an integer-spin quantum dot

The Kondo effect is a key many-body phenomenon in condensed matter physics. It concerns the interaction between a localised spin and free electrons. Discovered in metals containing small amounts of magnetic impurities, it is now a fundamental mechanism in a wide class of correlated electron systems. Control over single, localised spins has become relevant also in fabricated structures due to the rapid developments in nano-electronics. Experiments have already demonstrated artificial realisations of isolated magnetic impurities at metallic surfaces, nanometer-scale magnets, controlled transitions between two-electron singlet and triplet states, and a tunable Kondo effect in semiconductor quantum dots. Here, we report an unexpected Kondo effect realised in a few-electron quantum dot containing singlet and triplet spin states whose energy difference can be tuned with a magnetic field. This effect occurs for an even number of electrons at the degeneracy between singlet and triplet states. The characteristic energy scale is found to be much larger than for the ordinary spin-1/2 case.Comment: 12 page

Photo-Stimulated Electron Detrapping and the Two-State Model for Electron Transport in Nonpolar Liquids

In common nonpolar liquids, such as saturated hydrocarbons, a dynamic equilibrium between trapped (localized) and quasifree (extended) states has been postulated for the excess electron (the two-state model). Using time-resolved dc conductivity, the effect of 1064 nm laser photoexcitation of trapped electrons on the charge transport has been observed in liquid n-hexane and methylcyclohexane. The light promotes the electron from the trap into the conduction band of the liquid, instantaneously increasing the conductivity by orders of magnitude. From the analysis of the two-pulse, two-color photoconductivity data, the residence time of the electrons in traps has been estimated as ca. 8.4 ps for n-hexane and ca. 13 ps for methylcyclohexane (at 295 K). The rate of detrapping decreases at lower temperature with an activation energy of ca. 200 meV (280-320 K); the lifetime-mobility product for quasifree electrons scales linearly with the temperature. We suggest that the properties of trapped electrons in hydrocarbon liquids can be well accounted for using the simple electron bubble (Wigner-Seiz spherical well) model. The estimated localization time of the quasifree electron is 20-50 fs; both time estimates are in good agreement with the "quasiballistic" model. This localization time is significantly lower than the value of ca. 300 fs obtained using time-domain terahertz (THz) spectroscopy for the same system [E. Knoesel et al., J. Chem. Phys. 121, 394 (2004)]. We suggest that the THz signal originates from the oscillations of electron bubbles rather than the free-electron plasma; vibrations of these bubbles may be responsible for the deviations from the Drude behavior observed below 0.4 THz. Various implications of these results are discussed.Comment: 37 page, 5 figures; w Supplement of 13 pages and 5 figures; accepted by J. Chem. Phy