Optimal design of a 2-DOF pick-and-place parallel robot using dynamic performance indices and angular constraints

This paper presents an approach for the optimal design of a 2-DOF translational pick-and-place parallel robot. By taking account of the normalized inertial and centrifugal/Coriolis torques of a single actuated joint, two global dynamic performance indices are proposed for minimization. The pressure angles within a limb and between two limbs are considered as the kinematic constraints to prevent direct and indirect singularities. These considerations together form a multi-objective optimization problem that can then be solved by the modified goal attainment method. A numerical example is discussed. A number of robots designed by this approach have been integrated into production lines for carton packing in the pharmaceutical industry

The gray matter volume of the amygdala is correlated with the perception of melodic intervals: a voxel-based morphometry study

Music is not simply a series of organized pitches, rhythms, and timbres, it is capable of evoking emotions. In the present study, voxel-based morphometry (VBM) was employed to explore the neural basis that may link music to emotion. To do this, we identified the neuroanatomical correlates of the ability to extract pitch interval size in a music segment (i.e., interval perception) in a large population of healthy young adults (N = 264). Behaviorally, we found that interval perception was correlated with daily emotional experiences, indicating the intrinsic link between music and emotion. Neurally, and as expected, we found that interval perception was positively correlated with the gray matter volume (GMV) of the bilateral temporal cortex. More important, a larger GMV of the bilateral amygdala was associated with better interval perception, suggesting that the amygdala, which is the neural substrate of emotional processing, is also involved in music processing. In sum, our study provides one of first neuroanatomical evidence on the association between the amygdala and music, which contributes to our understanding of exactly how music evokes emotional responses

Singularity-invariant leg rearrangements in Stewart-Gough platforms

Postprint (author’s final draft

Patellar tendon ossification after partial patellectomy: a case report

<p>Abstract</p> <p>Introduction</p> <p>Patellar tendon ossification is a rare pathology that may be seen as a complication after sleeve fractures of the tibial tuberosity, total patellectomy during arthroplasty, intramedullary nailing of tibial fractures, anterior cruciate ligament reconstruction with patellar tendon autograft and knee injury without fracture. However, its occurrence after partial patellectomy surgery has never been reported in the literature.</p> <p>Case presentation</p> <p>We present the case of a 35-year-old Turkish man with a comminuted inferior patellar pole fracture that was treated with partial patellectomy. During the follow-up period, his patellar tendon healed with ossification and then ruptured from the inferior attachment to the tibial tubercle. The ossification was excised and the tendon was subsequently repaired.</p> <p>Conclusion</p> <p>To the best of our knowledge, this is the first report of patellar tendon ossification occurring after partial patellectomy. Orthopaedic surgeons are thus cautioned to be conscious of this rare complication after partial patellectomy.</p

Economic value of ecosystem services, minerals and oil in a melting Arctic: a preliminary assessment

The Arctic region is composed of unique marine and terrestrial ecosystems that provide a range of services to local and global populations. However, Arctic sea-ice and permafrost is melting at an unprecedented rate, threatening many of these ecosystems and the services they provide. This short communication provides a preliminary assessment of the quantity, distribution and economic value of key ecosystem services as well as geological resources such as oil and minerals provided by Arctic ecosystems to beneficiaries in the Arctic region and globally. Using biophysical and economic data from existing studies, preliminary estimates indicate that the Arctic currently provides about $$281 billion per year (in 2016 US$) in terms of food, mineral extraction, oil production, tourism, hunting, existence values and climate regulation. However, given predictions of ice-free summers by 2037, many of the ecosystem services may be lost. We hope that this communication stimulates discussion among policy-makers regarding the value of ecosystem services and such geological resources as minerals and oil provided by the Arctic region, and the potential ecosystem losses resulting from Arctic melt, so as to motivate decisions vis a vis climate change mitigation before Arctic ice disappears completely

Methods for biogeochemical studies of sea ice: The state of the art, caveats, and recommendations

AbstractOver the past two decades, with recognition that the ocean’s sea-ice cover is neither insensitive to climate change nor a barrier to light and matter, research in sea-ice biogeochemistry has accelerated significantly, bringing together a multi-disciplinary community from a variety of fields. This disciplinary diversity has contributed a wide range of methodological techniques and approaches to sea-ice studies, complicating comparisons of the results and the development of conceptual and numerical models to describe the important biogeochemical processes occurring in sea ice. Almost all chemical elements, compounds, and biogeochemical processes relevant to Earth system science are measured in sea ice, with published methods available for determining biomass, pigments, net community production, primary production, bacterial activity, macronutrients, numerous natural and anthropogenic organic compounds, trace elements, reactive and inert gases, sulfur species, the carbon dioxide system parameters, stable isotopes, and water-ice-atmosphere fluxes of gases, liquids, and solids. For most of these measurements, multiple sampling and processing techniques are available, but to date there has been little intercomparison or intercalibration between methods. In addition, researchers collect different types of ancillary data and document their samples differently, further confounding comparisons between studies. These problems are compounded by the heterogeneity of sea ice, in which even adjacent cores can have dramatically different biogeochemical compositions. We recommend that, in future investigations, researchers design their programs based on nested sampling patterns, collect a core suite of ancillary measurements, and employ a standard approach for sample identification and documentation. In addition, intercalibration exercises are most critically needed for measurements of biomass, primary production, nutrients, dissolved and particulate organic matter (including exopolymers), the CO2 system, air-ice gas fluxes, and aerosol production. We also encourage the development of in situ probes robust enough for long-term deployment in sea ice, particularly for biological parameters, the CO2 system, and other gases.This manuscript is a product of SCOR working group 140 on Biogeochemical Exchange Processes at Sea-Ice Interfaces (BEPSII); we thank BEPSII chairs Jacqueline Stefels and Nadja Steiner and SCOR executive director Ed Urban for their practical and moral support of this endeavour. This manuscript was first conceived at an EU COST Action 735 workshop held in Amsterdam in April 2011; in addition to COST 735, we thank the other participants of the “methods” break-out group at that meeting, namely Gerhard Dieckmann, Christoph Garbe, and Claire Hughes. Our editors, Steve Ackley and Jody Deming, and our reviewers, Mats Granskog and two anonymous reviewers, provided invaluable advice that not only identified and helped fill in some gaps, but also suggested additional ways to make what is by nature a rather dry subject (methods) at least a bit more interesting and accessible. We also thank the librarians at the Institute of Ocean Sciences for their unflagging efforts to track down the more obscure references we required. Finally, and most importantly, we thank everyone who has braved the unknown and made the new measurements that have helped build sea-ice biogeochemistry into the robust and exciting field it has become.This is the final published article, originally published in Elementa: Science of the Anthropocene, 3: 000038, doi: 10.12952/journal.elementa.00003

Serum anti-flagellin and anti-lipopolysaccharide immunoglobulins as predictors of linear growth faltering in Pakistani infants at risk for environmental enteric dysfunction

Background: Environmental Enteric Dysfunction (EED) in children from low-income countries has been linked to linear growth declines. There is a critical need to identify sensitive and early EED biomarkers.Objective: Determine whether levels of antibodies against bacterial components flagellin (flic) and lipopolysaccharide (LPS) predict poor growth.Design/Methods: In a prospective birth cohort of 380 children in rural Pakistan blood and stool samples were obtained at ages 6 and 9 months. Linear mixed effects models were used to examine longitudinal associations between quartiles of anti-flic and anti-LPS antibodies and changes in LAZ, WAZ and WLZ scores. Spearman\u27s correlations were measured between anti-flic and anti-LPS immunoglobulins with measures of systemic/enteric inflammation and intestinal regeneration.Results: Anti-LPS IgA correlated significantly with CRP, AGP and Reg1 serum at 6mo and with MPO at 9mo. In multivariate analysis at 6mo of age, higher anti-LPS IgA levels predicted greater declines in LAZ scores over subsequent 18mo (comparing highest to lowest quartile, β (SE) change in LAZ score/year = -0.313 (0.125), p-value = 0.013). Anti-flic Ig A in the two highest quartiles measured at 9mo of age had declines in LAZ of -0.269 (0.126), p = 0.033; and -0.306 (0.129), p = 0.018 respectively, during the subsequent 18mo of life, compared to those in the lowest quartile of anti-flic IgA.Conclusions and Relevance: Elevated anti-flic IgA and anti-LPS IgA antibodies at 6 and 9mo, predict declines in linear growth. Systemic and enteric inflammation correlated with anti-LPS IgA provides mechanistic considerations for potential future interventions

A model-based analysis of physical and biological controls on ice algal and pelagic primary production in Resolute Passage

A coupled 1-D sea ice-ocean physical-biogeochemical model was developed to investigate the processes governing ice algal and phytoplankton blooms in the seasonally ice-covered Arctic Ocean. The 1-D column is representative of one grid cell in 3-D model applications and provides a tool for parameterization development. The model was applied to Resolute Passage in the Canadian Arctic Archipelago and assessed with observations from a field campaign during spring of 2010. The factors considered to limit the growth of simulated ice algae and phytoplankton were light, nutrients, and in the case of ice algae, ice melt. In addition to the standard simulation, several model experiments were conducted to determine the sensitivity of the simulated ice algal bloom to parameterizations of light, mortality, and pre-bloom biomass. Model results indicated that: (1) ice algae limit subsequent pelagic productivity in the upper 10 m by depleting nutrients to limiting levels; (2) light availability and pre-bloom biomass determine the onset timing of the ice algal bloom; (3) the maximum biomass is relatively insensitive to the pre-bloom biomass, but is limited by nutrient availability; (4) a combination of linear and quadratic parameterizations of mortality rate is required to adequately simulate the evolution of the ice algal bloom; and (5) a sinking rate for large detritus greater than a threshold of ∼10 m d–1 effectively strips the surface waters of the limiting nutrient (silicate) after the ice algal bloom, supporting the development of a deep chlorophyll maximum

The EEG signature of sensory evidence accumulation during decision formation closely tracks subjective perceptual experience

How neural representations of low-level visual information are accessed by higher-order processes to inform decisions and give rise to conscious experience is a longstanding question. Research on perceptual decision making has revealed a late event-related EEG potential (the Centro-Parietal Positivity, CPP) to be a correlate of the accumulation of sensory evidence. We tested how this evidence accumulation signal relates to externally presented (physical) and internally experienced (subjective) sensory evidence. Our results show that the known relationship between the physical strength of the external evidence and the evidence accumulation signal (reflected in the CPP amplitude) is mediated by the level of subjective experience of stimulus strength. This shows that the CPP closely tracks the subjective perceptual evidence, over and above the physically presented evidence. We conclude that a remarkably close relationship exists between the evidence accumulation process (i.e. CPP) and subjective perceptual experience, suggesting that neural decision processes and components of conscious experience are tightly linked

Sensitivity to musical emotion is influenced by tonal structure in congenital amusia

Emotional communication in music depends on multiple attributes including psychoacoustic features and tonal system information, the latter of which is unique to music. The present study investigated whether congenital amusia, a lifelong disorder of musical processing, impacts sensitivity to musical emotion elicited by timbre and tonal system information. Twenty-six amusics and 26 matched controls made tension judgments on Western (familiar) and Indian (unfamiliar) melodies played on piano and sitar. Like controls, amusics used timbre cues to judge musical tension in Western and Indian melodies. While controls assigned significantly lower tension ratings to Western melodies compared to Indian melodies, thus showing a tonal familiarity effect on tension ratings, amusics provided comparable tension ratings for Western and Indian melodies on both timbres. Furthermore, amusics rated Western melodies as more tense compared to controls, as they relied less on tonality cues than controls in rating tension for Western melodies. The implications of these findings in terms of emotional responses to music are discussed