49 research outputs found

    Learning Flexible and Reusable Locomotion Primitives for a Microrobot

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    The design of gaits for robot locomotion can be a daunting process which requires significant expert knowledge and engineering. This process is even more challenging for robots that do not have an accurate physical model, such as compliant or micro-scale robots. Data-driven gait optimization provides an automated alternative to analytical gait design. In this paper, we propose a novel approach to efficiently learn a wide range of locomotion tasks with walking robots. This approach formalizes locomotion as a contextual policy search task to collect data, and subsequently uses that data to learn multi-objective locomotion primitives that can be used for planning. As a proof-of-concept we consider a simulated hexapod modeled after a recently developed microrobot, and we thoroughly evaluate the performance of this microrobot on different tasks and gaits. Our results validate the proposed controller and learning scheme on single and multi-objective locomotion tasks. Moreover, the experimental simulations show that without any prior knowledge about the robot used (e.g., dynamics model), our approach is capable of learning locomotion primitives within 250 trials and subsequently using them to successfully navigate through a maze.Comment: 8 pages. Accepted at RAL+ICRA201

    Ancient DNA Analysis and Stable Isotope Ecology of Sea Turtles (Cheloniidae) from the Gold Rush-era (1850s) Eastern Pacific Ocean

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    Historical and archaeological evidence documents the importation of sea turtles from the eastern Pacific Ocean (Baja California) to California during the Gold Rush (1848–1855) and through the end of 19th century, but it is unknown whether these 19th century sea turtles foraged in similar ways to their modern counterparts. To identify the species of two Gold Rush-era sea turtle specimens recovered from archaeological deposits in San Francisco, California, we first analyze ancient DNA (aDNA). We then analyze carbon (δ13Ccol), nitrogen (δ15N), and hydrogen (δD) stable isotopes of bone collagen and carbon (δ13Cap) and oxygen (δ18Oap) stable isotopes of bone apatite to test if eastern Pacific sea turtle diets have changed over the past 160 years. Ancient DNA confirms that both archaeological specimens are green sea turtles (Chelonia mydas). The stable isotope values from the 19th-century specimens are statistically indistinguishable from the modern comparatives in both δ13Ccoland δ15N, suggesting that green sea turtle dietary intake has remained relatively unchanged since the 1850s. However, the values are unclear for δD and δ18Oapand require additional research.Support for this work came the University of Oklahoma Libraries Open Access Fund.YesOpen Quaternary is an international peer-reviewed venue for contributions that consider the changing environment of the Quaternary, as well as the development of humanity

    Familial hypercholesterolaemia in children and adolescents from 48 countries: a cross-sectional study

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    Background: Approximately 450 000 children are born with familial hypercholesterolaemia worldwide every year, yet only 2·1% of adults with familial hypercholesterolaemia were diagnosed before age 18 years via current diagnostic approaches, which are derived from observations in adults. We aimed to characterise children and adolescents with heterozygous familial hypercholesterolaemia (HeFH) and understand current approaches to the identification and management of familial hypercholesterolaemia to inform future public health strategies. Methods: For this cross-sectional study, we assessed children and adolescents younger than 18 years with a clinical or genetic diagnosis of HeFH at the time of entry into the Familial Hypercholesterolaemia Studies Collaboration (FHSC) registry between Oct 1, 2015, and Jan 31, 2021. Data in the registry were collected from 55 regional or national registries in 48 countries. Diagnoses relying on self-reported history of familial hypercholesterolaemia and suspected secondary hypercholesterolaemia were excluded from the registry; people with untreated LDL cholesterol (LDL-C) of at least 13·0 mmol/L were excluded from this study. Data were assessed overall and by WHO region, World Bank country income status, age, diagnostic criteria, and index-case status. The main outcome of this study was to assess current identification and management of children and adolescents with familial hypercholesterolaemia. Findings: Of 63 093 individuals in the FHSC registry, 11 848 (18·8%) were children or adolescents younger than 18 years with HeFH and were included in this study; 5756 (50·2%) of 11 476 included individuals were female and 5720 (49·8%) were male. Sex data were missing for 372 (3·1%) of 11 848 individuals. Median age at registry entry was 9·6 years (IQR 5·8-13·2). 10 099 (89·9%) of 11 235 included individuals had a final genetically confirmed diagnosis of familial hypercholesterolaemia and 1136 (10·1%) had a clinical diagnosis. Genetically confirmed diagnosis data or clinical diagnosis data were missing for 613 (5·2%) of 11 848 individuals. Genetic diagnosis was more common in children and adolescents from high-income countries (9427 [92·4%] of 10 202) than in children and adolescents from non-high-income countries (199 [48·0%] of 415). 3414 (31·6%) of 10 804 children or adolescents were index cases. Familial-hypercholesterolaemia-related physical signs, cardiovascular risk factors, and cardiovascular disease were uncommon, but were more common in non-high-income countries. 7557 (72·4%) of 10 428 included children or adolescents were not taking lipid-lowering medication (LLM) and had a median LDL-C of 5·00 mmol/L (IQR 4·05-6·08). Compared with genetic diagnosis, the use of unadapted clinical criteria intended for use in adults and reliant on more extreme phenotypes could result in 50-75% of children and adolescents with familial hypercholesterolaemia not being identified. Interpretation: Clinical characteristics observed in adults with familial hypercholesterolaemia are uncommon in children and adolescents with familial hypercholesterolaemia, hence detection in this age group relies on measurement of LDL-C and genetic confirmation. Where genetic testing is unavailable, increased availability and use of LDL-C measurements in the first few years of life could help reduce the current gap between prevalence and detection, enabling increased use of combination LLM to reach recommended LDL-C targets early in life

    Association of BMI, lipid-lowering medication, and age with prevalence of type 2 diabetes in adults with heterozygous familial hypercholesterolaemia: a worldwide cross-sectional study

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    Background: Statins are the cornerstone treatment for patients with heterozygous familial hypercholesterolaemia but research suggests it could increase the risk of type 2 diabetes in the general population. A low prevalence of type 2 diabetes was reported in some familial hypercholesterolaemia cohorts, raising the question of whether these patients are protected against type 2 diabetes. Obesity is a well known risk factor for the development of type 2 diabetes. We aimed to investigate the associations of known key determinants of type 2 diabetes with its prevalence in people with heterozygous familial hypercholesterolaemia. Methods: This worldwide cross-sectional study used individual-level data from the EAS FHSC registry and included adults older than 18 years with a clinical or genetic diagnosis of heterozygous familial hypercholesterolaemia who had data available on age, BMI, and diabetes status. Those with known or suspected homozygous familial hypercholesterolaemia and type 1 diabetes were excluded. The main outcome was prevalence of type 2 diabetes overall and by WHO region, and in relation to obesity (BMI ≥30·0 kg/m2) and lipid-lowering medication as predictors. The study population was divided into 12 risk categories based on age (tertiles), obesity, and receiving statins, and the risk of type 2 diabetes was investigated using logistic regression. Findings: Among 46 683 adults with individual-level data in the FHSC registry, 24 784 with heterozygous familial hypercholesterolaemia were included in the analysis from 44 countries. 19 818 (80%) had a genetically confirmed diagnosis of heterozygous familial hypercholesterolaemia. Type 2 diabetes prevalence in the total population was 5·7% (1415 of 24 784), with 4·1% (817 of 19 818) in the genetically diagnosed cohort. Higher prevalence of type 2 diabetes was observed in the Eastern Mediterranean (58 [29·9%] of 194), South-East Asia and Western Pacific (214 [12·0%] of 1785), and the Americas (166 [8·5%] of 1955) than in Europe (excluding the Netherlands; 527 [8·0%] of 6579). Advancing age, a higher BMI category (obesity and overweight), and use of lipid-lowering medication were associated with a higher risk of type 2 diabetes, independent of sex and LDL cholesterol. Among the 12 risk categories, the probability of developing type 2 diabetes was higher in people in the highest risk category (aged 55–98 years, with obesity, and receiving statins; OR 74·42 [95% CI 47·04–117·73]) than in those in the lowest risk category (aged 18–38 years, without obesity, and not receiving statins). Those who did not have obesity, even if they were in the upper age tertile and receiving statins, had lower risk of type 2 diabetes (OR 24·42 [15·57–38·31]). The corresponding results in the genetically diagnosed cohort were OR 65·04 (40·67–104·02) for those with obesity in the highest risk category and OR 20·07 (12·73–31·65) for those without obesity. Interpretation: Adults with heterozygous familial hypercholesterolaemia in most WHO regions have a higher type 2 diabetes prevalence than in Europe. Obesity markedly increases the risk of diabetes associated with age and use of statins in these patients. Our results suggest that heterozygous familial hypercholesterolaemia does not protect against type 2 diabetes, hence managing obesity is essential to reduce type 2 diabetes in this patient population. Funding: Pfizer, Amgen, MSD, Sanofi-Aventis, Daiichi-Sankyo, and Regeneron

    Poverty in the Palestinian Territories

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    The Palestinian Territories have a uniquely fragmented geography, characterized by the isolation of Gaza from the rest of the world, and the man-made barriers to mobility within the West Bank. The internal mobility restrictions imposed by Israel, unique to the West Bank, play an important role in explaining spatial variations in outcomes within the West Bank. This is strikingly analogous to the role of Gaza s external barriers in explaining the divergence between the West Bank and Gaza. These have consequences for poverty and economic development. Detailed analysis using a series of labor force and household surveys were undertaken as part of the West Bank and Gaza Poverty and Inclusion Assessment, Coping with Conflict? The analysis shows that over the last decade, internal and external barriers have been associated with tremendous constraints to growth and investment, which is evident in high rates of unemployment, especially in Gaza and among women and youth

    Months Report from the Phase 3 Study of Plerixafor+G-CSF VS. Placebo+G-CSF for Mobilization of Hematopoietic Stem Cell for Autologous Transplant in Patients with NHL.

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    Abstract Introduction: We previously reported that plerixafor + G-CSF was as safe as and more effective than placebo + G-CSF in mobilizing hematopoietic stem cell for autologous transplant in patients with non-Hodgkins lymphoma (NHL) through 100 days follow-up (DiPersio ASH 2007). We report herein the 12 months data. Methods: This was a phase 3, multicenter, randomized, double-blind, placebo-controlled study. NHL patients requiring an autologous hematopoietic stem cell transplant were eligible. Patients received G-CSF (10 μg/kg) subcutaneously daily for up to 8 days. Beginning on evening of Day 4 and continuing daily for up to 4 days, patients received either plerixafor (240 μg/kg) or placebo subcutaneously. Starting on morning of Day 5, patients began daily apheresis for up to 4 days or until ≥ 5 x 106 CD34+cells/kg were collected. We report herein the 12 months graft durability and hematology data. Results: As reported previously, 89/150 (59%) patients in the plerixafor group and 29/148 (20%) patients in the placebo group met the primary endpoint of collecting ≥ 5 x 106 CD34+ cells/kg in ≤ 4 days of apheresis, p &amp;lt; 0.001. 135 patients (90%) in plerixafor group and 82 patients (55%) in placebo group underwent transplantation. Median time to neutrophil and platelet engraftment was similar in both groups. There were no differences in graft durability through 12 months follow-up between the two groups. Two plerixa for treated patients had graft failure (one had pre-existing MDS and one developed AML). One plerixafor-treated patient had delayed platelet engraftment. The hematology profiles were similar between the two groups through 12 months follow-up, except that patients in the plerixafor group had significantly higher platelet count at 12 months than patients in the placebo group (p=0.026) (Table 1). During the 12 months follow-up, 14/135 (10.4%) patients in plerixafor group and 10/82 (12.2%) patients in the placebo group died. 7/14 in the plerixafor group and 5/10 in the placebo group died of disease progression. Plerixafor + G-CSF Placebo + G-CSF Hematology data presented as mean ± SD and n= number of patients with available data aAll patients who underwent transplantation bAll patients who underwent transplantation and had laboratory data at the study visit cP values were NS for all variables at all time points between groups except for platelet count at 12 months (p=0.026) Graft durability (n, %) 100 daysa 128/135 (94.8%) 78/82 (95.1%) 6 monthsb 120/123 (97.6%) 77/78 (98.7%) 12 monthsb 110/112 (98.2%) 65/65 (100.0%) Platelet (x 109/L) 100 days 183 ± 83 (n= 113) 169 ± 81 (n=63) 6 months 190 ± 78 (n=100) 180 ± 77 (n=64) 12 monthsc 209 ± 81 (n=50) 170 ± 78 (n=37) Neutrophils (x 109/L) 100 days 3.1 ± 1.7 (n=107) 3.2 ± 2.1 (n=61) 6 months 3.3 ± 1.4 (n=98) 3.8 ± 2.6 (n=64) 12 months 3.5 ± 1.4 (n=50) 4.2 ± 2.7 (n=38) Hemogloblin (mg/dL) 100 days 12.3 ± 1.5 (n=112) 12.3 ± 1.5 (n=63) 6 months 12.5 ± 1.5 (n=100) 12.4 ± 1.5 (n=64) 12 months 13.0 ± 1.4 (n=50) 12.7 ± 1.6 (n=37) Conclusions: The addition of plerixafor to G-CSF resulted in higher CD34+ cell collection in fewer days of apheresis and higher proportion of patients proceeding to transplant than G-CSF alone. Importantly, this 12 months report showed that transplants with cells collected with plerixafor resulted in graft durability rates that were similar to cells collected with G-CSF alone.</jats:p
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