104 research outputs found
Using control synthesis to generate corner cases: A case study on autonomous driving
This paper employs correct-by-construction control synthesis, in particular
controlled invariant set computations, for falsification. Our hypothesis is
that if it is possible to compute a "large enough" controlled invariant set
either for the actual system model or some simplification of the system model,
interesting corner cases for other control designs can be generated by sampling
initial conditions from the boundary of this controlled invariant set.
Moreover, if falsifying trajectories for a given control design can be found
through such sampling, then the controlled invariant set can be used as a
supervisor to ensure safe operation of the control design under consideration.
In addition to interesting initial conditions, which are mostly related to
safety violations in transients, we use solutions from a dual game, a
reachability game for the safety specification, to find falsifying inputs. We
also propose optimization-based heuristics for input generation for cases when
the state is outside the winning set of the dual game. To demonstrate the
proposed ideas, we consider case studies from basic autonomous driving
functionality, in particular, adaptive cruise control and lane keeping. We show
how the proposed technique can be used to find interesting falsifying
trajectories for classical control designs like proportional controllers,
proportional integral controllers and model predictive controllers, as well as
an open source real-world autonomous driving package.Comment: To appear at EMSOFT 201
Colliding Wave Solutions in a Symmetric Non-metric Theory
A method is given to generate the non-linear interaction (collision) of
linearly polarized gravity coupled torsion waves in a non-metric theory.
Explicit examples are given in which strong mutual focussing of gravitational
waves containing impulsive and shock components coupled with torsion waves does
not result in a curvature singularity. However, the collision of purely torsion
waves displays a curvature singularity in the region of interaction.Comment: 16 pages, 1 ps figure, It will appear in Int. Jour. of Theor. Physic
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Immigration represents a promising counter-narrative for Rust Belt cities in the 21st century. Increasingly, both immigrants and refugees are part of the comeback stories of Northeastern and Midwestern cities from Buffalo, to Dayton and Pittsburgh. This review explores recent research in urban geography and allied disciplines focusing on the international migration patterns,
processes, and politics reshaping the urban geography of the American Rust Belt. Recent research sheds crucial light on how im/migrant lives are reshaping urban landscapes of Rust Belt cities, and conversely, how local immigration policies in these cities are rearranging the uneven geographies of immigrant receptivity across the U.S. Overall, this review highlights the limitations of the singular spatial imaginary of the Rust Belt advanced previously by many urbanists. Rather, this review illustrates the rich, complex, and tangled contemporary spatial nuances associated with international migration in this region. These spatial nuances are complicated by increasingly exclusionary immigration policy and rhetoric at the federal level since January of 2017
Inositols: From established knowledge to novel approaches
Myo-inositol (myo-Ins) and D-chiro-inositol (D-chiro-Ins) are natural compounds involved in many biological pathways. Since the discovery of their involvement in endocrine signal transduction, myo-Ins and D-chiro-Ins supplementation has contributed to clinical approaches in ameliorating many gynecological and endocrinological diseases. Currently both myo-Ins and D-chiro-Ins are well-tolerated, effective alternative candidates to the classical insulin sensitizers, and are useful treatments in preventing and treating metabolic and reproductive disorders such as polycystic ovary syndrome (PCOS), gestational diabetes mellitus (GDM), and male fertility disturbances, like sperm abnormalities. Moreover, besides metabolic activity, myo-Ins and D-chiro-Ins deeply influence steroidogenesis, regulating the pools of androgens and estrogens, likely in opposite ways. Given the complexity of inositol-related mechanisms of action, many of their beneficial effects are still under scrutiny. Therefore, continuing research aims to discover new emerging roles and mechanisms that can allow clinicians to tailor inositol therapy and to use it in other medical areas, hitherto unexplored. The present paper outlines the established evidence on inositols and updates on recent research, namely concerning D-chiro-Ins involvement into steroidogenesis. In particular, D-chiro-Ins mediates insulin-induced testosterone biosynthesis from ovarian thecal cells and directly affects synthesis of estrogens by modulating the expression of the aromatase enzyme. Ovaries, as well as other organs and tissues, are characterized by a specific ratio of myo-Ins to D-chiro-Ins, which ensures their healthy state and proper functionality. Altered inositol ratios may account for pathological conditions, causing an imbalance in sex hormones. Such situations usually occur in association with medical conditions, such as PCOS, or as a consequence of some pharmacological treatments. Based on the physiological role of inositols and the pathological implications of altered myo-Ins to D-chiro-Ins ratios, inositol therapy may be designed with two different aims: (1) restoring the inositol physiological ratio; (2) altering the ratio in a controlled way to achieve specific effects
The genetic architecture of membranous nephropathy and its potential to improve non-invasive diagnosis
Membranous Nephropathy (MN) is a rare autoimmune cause of kidney failure. Here we report a genome-wide association study (GWAS) for primary MN in 3,782 cases and 9,038 controls of East Asian and European ancestries. We discover two previously unreported loci, NFKB1 (rs230540, OR = 1.25, P = 3.4 × 10-12) and IRF4 (rs9405192, OR = 1.29, P = 1.4 × 10-14), fine-map the PLA2R1 locus (rs17831251, OR = 2.25, P = 4.7 × 10-103) and report ancestry-specific effects of three classical HLA alleles: DRB1*1501 in East Asians (OR = 3.81, P = 2.0 × 10-49), DQA1*0501 in Europeans (OR = 2.88, P = 5.7 × 10-93), and DRB1*0301 in both ethnicities (OR = 3.50, P = 9.2 × 10-23 and OR = 3.39, P = 5.2 × 10-82, respectively). GWAS loci explain 32% of disease risk in East Asians and 25% in Europeans, and correctly re-classify 20-37% of the cases in validation cohorts that are antibody-negative by the serum anti-PLA2R ELISA diagnostic test. Our findings highlight an unusual genetic architecture of MN, with four loci and their interactions accounting for nearly one-third of the disease risk
The genetic architecture of membranous nephropathy and its potential to improve non-invasive diagnosis
Membranous Nephropathy (MN) is a rare autoimmune cause of kidney failure. Here we report a genome-wide association study (GWAS) for primary MN in 3,782 cases and 9,038 controls of East Asian and European ancestries. We discover two previously unreported loci, NFKB1 (rs230540, OR = 1.25, P = 3.4 × 10-12) and IRF4 (rs9405192, OR = 1.29, P = 1.4 × 10-14), fine-map the PLA2R1 locus (rs17831251, OR = 2.25, P = 4.7 × 10-103) and report ancestry-specific effects of three classical HLA alleles: DRB1*1501 in East Asians (OR = 3.81, P = 2.0 × 10-49), DQA1*0501 in Europeans (OR = 2.88, P = 5.7 × 10-93), and DRB1*0301 in both ethnicities (OR = 3.50, P = 9.2 × 10-23 and OR = 3.39, P = 5.2 × 10-82, respectively). GWAS loci explain 32% of disease risk in East Asians and 25% in Europeans, and correctly re-classify 20-37% of the cases in validation cohorts that are antibody-negative by the serum anti-PLA2R ELISA diagnostic test. Our findings highlight an unusual genetic architecture of MN, with four loci and their interactions accounting for nearly one-third of the disease risk
Evaluation of thyroid function status among postmenopausal women with and without osteoporosis
Objective: To investigate the relationship between thyroid function status and bone mineral density (BMD) among women with postmenopausal osteoporosis. Methods: A retrospective study was performed among 1217 women aged 45-80 years who attended the Department of Obstetrics and Gynecology at Dokuz Eylul University, Izmir, Turkey, between August 1, 2009, and June 1, 2013. Eligible participants were grouped according to the presence or absence of osteoporosis as defined by BMD measurements at the lumbar vertebrae (Ll-L4), femoral neck, or trochanter of the femur. Serum levels of free tri-iodothyronine, free tetraiodothyronine, and thyroid-stimulating hormone (TSH) were assessed. Results: The 303 women with osteoporosis had a lower mean TSH level (1.8 mIU/L) than did the 914 women without osteoporosis (1.9 mIU/L; P = 0.01). A positive correlation between TSH level and measures of BMD was observed (P = 0.01). The TSH level was associated with a protective effect in a regression model for development of osteoporosis; the odds ratio was 0.68 (95% confidence interval 0.53-0.86). Conclusion: Osteoporosis appeared to be independently associated with serum TSH level. Maintaining TSH levels within the upper limit of the reference range during treatment of hypothyroidism could be important to prevent osteoporosis among postmenopausal women. (C) 2016 International Federation of Gynecology and Obstetrics. Published by Elsevier Ireland Ltd. All rights reserved
Teaching cell division to secondary school students: an investigation of difficulties experienced by Turkish teachers
This study examines the difficulties biology teachers face when teaching cell division in the secondary schools of the central part of the Erzurum province in Turkey. During this research, a questionnaire was distributed to a total of 36 secondary school biology teachers
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