Task planning and control synthesis for robotic manipulation in space applications

Space-based robotic systems for diagnosis, repair and assembly of systems will require new techniques of planning and manipulation to accomplish these complex tasks. Results of work in assembly task representation, discrete task planning, and control synthesis which provide a design environment for flexible assembly systems in manufacturing applications, and which extend to planning of manipulatiuon operations in unstructured environments are summarized. Assembly planning is carried out using the AND/OR graph representation which encompasses all possible partial orders of operations and may be used to plan assembly sequences. Discrete task planning uses the configuration map which facilitates search over a space of discrete operations parameters in sequential operations in order to achieve required goals in the space of bounded configuration sets

Age and growth, reproduction and diet of the red blenny Parablennius ruber (Blenniidae)

Basic biological information for a sublittoral population of the red blenny Parablennius ruber is presented based on a two-year study involving 2350 specimens. The length-weight relationship was given by TW = 0.011 x TL2.963 (where TW = total weight, in g; TL = total length, in cm). Age at length data was inferred by modal analysis of the monthly length-frequency distributions. The parameters of the fitted von Bertalanffy growth equation (with seasonal component, birth date on February, 15th) were L∞ = 13.22 cm; K = 0.62 year-1; to = -0.39 year; C = 0.68; WP = 0.97. Macroscopic examination of the gonads, and analysis of the monthly values of the gonadosomatic index, indicated that reproduction occurs in winter, with a maximum in February and March, when water temperatures are low. Individuals become sexually mature around 6 cm TL, a size that can be reached in less than one year. Stomach contents suggest an omnivorous diet mainly composed of scrapped filamentous algae and associated invertebrates

Comparison of Techniques and Solvents on the Antimicrobial and Antioxidant Potential of Extracts from Acacia dealbata and Olea europaea

Ethnopharmacological use of plant natural extracts has been known since ancient times. The optimization of plant molecule extraction is fundamental in obtaining relevant extraction yields. The main purpose of this study was to understand the role of different extraction techniques (solid-liquid, ultrasound, Soxhlet, and microwave) and solvents (water, methanol, ethanol, acetone, dichloromethane, and hexane) on the antimicrobial and antioxidant activities of extracts from Olea europaea (olive) and Acacia dealbata (mimosa). Crude plant extracts were evaluated for their antimicrobial activity against Staphylococcus aureus and Escherichia coli by the disk diffusion method. The antioxidant capacity of the extracts was determined by ABTS (2,2-azinobis (3-ethyl-benzothiazoline-6-sulfonic acid)) and DPPH (2,2-diphenyl-1-picrylhydrazyl) methods. In terms of extraction yield, ultrasound extraction and the solvents methanol, acetone (O. europaea) or water (A. dealbata) were found to be the best options. However, ethanol and acetone proved to be the best solvents to extract compounds with antimicrobial activity and antioxidant capacity, respectively (regardless of the extraction method employed). Soxhlet and microwave were the best techniques to extract compounds with antimicrobial activity, whereas any of the tested techniques showed the ability to extract compounds with antioxidant capacity. In most of the cases, both plant extracts (mimosa and olive) were more efficient against S. aureus than E. coli. In the present study, both mimosa and olive leaf crude extracts proved to have antimicrobial and antioxidant activities, increasing the demand of these natural products as a source of compounds with health benefits.</jats:p

A Pomset-Based Model for Estimating Workcells' Setups in Assembly Sequence Planning

This paper presents a model based on pomsets (partially ordered multisets) for estimating the minimum number of setups in the workcells in Assembly Sequence Planning. This problem is focused through the minimization of the makespan (total assembly time) in a multirobot system. The planning model considers, apart from the durations and resources needed for the assembly tasks, the delays due to the setups in the workcells. An A* algorithm is used to meet the optimal solution. It uses the And/Or graph for the product to assemble, that corresponds to a compressed representation of all feasible assembly plans. Two basic admissible heuristic functions can be defined from relaxed models of the problem, considering the precedence constraints and the use of resources separately. The pomset-based model presented in this paper takes into account the precedence constraints in order to obtain a better estimation for the second heuristic function, so that the performance of the algorithm could be improved

Serine hydroxymethyl transferase is required for optic lobe neuroepithelia development in Drosophila

Funding Information: This work was supported by the European Research Council under the European Union’s Horizon 2020 research and innovation programme (H2020-ERC-2017-STG-GA 759853-StemCellHabitat); Wellcome Trust and Howard Hughes Medical Institute (HHMI-208581/Z/17/ZMetabolicRegSCfate); EMBO Installation grant (H2020-EMBO-3311/2017/G2017) and Fundaçaõ para a Ciência e a Tecnologia (IF/01265/2014/CP1252/CT0004 and SFRH/BD/135262/2017 Eunice Silva); ‘Inova4Health – UIDB/04462/2020 and UIDP/04462/2020, and the Associated Laboratory LS4FUTURE (LA/P/0087/2020), Fundaçaõ para a Ciência e a Tecnologia/Ministério da Ciência, Tecnologia e Ensino Superior’. E.A.B.S. was partially funded by a Fundaçaõ para a Ciência e a Tecnologia doctoral fellowship under the PGCD-Graduate Program Science for Development (SFRH/BD/135262/ 2017). This research was funded in part by the Wellcome Trust [208581/Z/17/Z]. Open Access funding provided by the European Research Council. Deposited in PMC for immediate release. Publisher Copyright: © 2023. Published by The Company of Biologists Ltd.Cell fate and growth require one-carbon units for the biosynthesis of nucleotides, methylation reactions and redox homeostasis, provided by one-carbon metabolism. Consistently, defects in one-carbon metabolism lead to severe developmental defects, such as neural tube defects. However, the role of this pathway during brain development and in neural stem cell regulation is poorly understood. To better understand the role of one carbon metabolism we focused on the enzyme Serine hydroxymethyl transferase (Shmt), a key factor in the one-carbon cycle, during Drosophila brain development. We show that, although loss of Shmt does not cause obvious defects in the central brain, it leads to severe phenotypes in the optic lobe. The shmt mutants have smaller optic lobe neuroepithelia, partly justified by increased apoptosis. In addition, shmt mutant neuroepithelia have morphological defects, failing to form a lamina furrow, which likely explains the observed absence of lamina neurons. These findings show that one-carbon metabolism is crucial for the normal development of neuroepithelia, and consequently for the generation of neural progenitor cells and neurons. These results propose a mechanistic role for one-carbon during brain development.publishersversionpublishe

Forage Legumes in Tropical Regions: Recent Advances and Future Challenges

Nitrogen input in tropical pastures increases forage and animal productivity. Forage legumes can fix atmospheric nitrogen and are the most economical way to add this nutrient to the soil. Our objective was to report the benefits of forage legumes in tropical pastures and possible strategies to implement different forage legumes. In tropical conditions, such as in Brazil, the use of forage legumes is still scarce. Even with low legume adoption on tropical pastures, forage legumes can provide ecosystem services. Increased animal productivity is the first ecosystem service provided by these legumes, mainly due to the addition of nitrogen that is typically the most limiting nutrient on tropical soils and yet the most important driver of plant growth and development. Legumes also provide an opportunity to increase nitrogen cycling in grassland, reducing grassland degradation. Pastures that include legumes have greater litter quality than grass monocultures, increasing soil organic matter at a faster rate. Legumes improve diet nutritive value and animal performance, resulting in reduced enteric methane emissions per unit of animal product. Additionally, legumes are generally associated with lower nitrous oxide emissions than N-fertilized grass swards and reduce the carbon footprint from the system due to nitrogen manufacture, transport, storage, and application. However, the greatest challenge in tropical pastures is to increase the adoption of forage legumes. It is necessary to understand the role of different legumes in the pasture environment. Some legumes have high herbage accumulation and biological nitrogen fixation potential, but they have low canopy stability; nonetheless, they could be used on short-lived pastures as well as integrated crop-livestock systems. When the objective is to achieve grass-legume stability in mixed pastures, it is necessary to use clonal propagation legumes and provide appropriate defoliation management to minimize light competition among plant communities

Absolute and convective instabilities of parallel propagating circularly polarized Alfvén waves: numerical results

Context.The stability of parallel propagating circularly polarized Alfvén waves (pump waves) has been studied for more than four decades with the use of normal mode analysis. It is well known that the normal mode analysis does not answer the question if a pump wave looks stable or unstable in a particular reference frame. To answer this question it is necessary to find out if the instability is absolute or convective in this reference frame. Aims.We extend our previous study of absolute and convective instabilities of pump waves with small amplitude to pump waves with arbitrary amplitude. Methods.To study the absolute and convective instabilities of pump waves with arbitrary amplitude we numerically implement Brigg's method. Results.We show that the wave is absolutely unstable in a reference frame moving with the velocity U with respect to the rest plasma if U satisfies the inequality Ul Ur) we study the signalling problem. We show that spatially amplifying waves exist only when the signalling frequency is in two symmetric frequency bands, and calculate the dependences of the boundaries of these bands on U for different values of a . We also obtain the dependences of the maximum spatial amplification rate on U for different values of a . The implication of these results on the interpretation of observational data from space missions is discussed. In particular, it is shown that circularly polarized Alfvén waves propagating in the solar wind are convectively unstable in a reference frame of any realistic spacecraft

Spun biotextiles in tissue engineering and biomolecules delivery systems

Nowadays, tissue engineering is described as an interdisciplinary field that combines engineering principles and life sciences to generate implantable devices to repair, restore and/or improve functions of injured tissues. Such devices are designed to induce the interaction and integration of tissue and cells within the implantable matrices and are manufactured to meet the appropriate physical, mechanical and physiological local demands. Biodegradable constructs based on polymeric fibers are desirable for tissue engineering due to their large surface area, interconnectivity, open pore structure, and controlled mechanical strength. Additionally, biodegradable constructs are also very sought-out for biomolecule delivery systems with a target-directed action. In the present review, we explore the properties of some of the most common biodegradable polymers used in tissue engineering applications and biomolecule delivery systems and highlight their most important uses.Authors acknowledge the Portuguese Foundation for Science and Technology (FCT), FEDER funds by means of Portugal 2020 Competitive Factors Operational Program (POCI) and the Portuguese Government (OE) for funding the project PEPTEX with reference PTDC/CTM-TEX/28074/2017 (POCI-01-0145- FEDER-028074). Authors also acknowledge project UID/CTM/00264/2020 of Centre for Textile Science and Technology (2C2T), funded by national funds through FCT/MCTES

Anharmonic transitions in nearly dry L-cysteine I

Two special dynamical transitions of universal character have been recently observed in macromolecules at $T_{D}\sim 180 - 220$ K and $T^{*}\sim 100$ K. Despite their relevance, a complete understanding of the nature of these transitions and their consequences for the bio-activity of the macromolecule is still lacking. Our results and analysis concerning the temperature dependence of structural, vibrational and thermodynamical properties of the orthorhombic polymorph of the amino acid L-cysteine (at a hydration level of 3.5%) indicated that the two referred temperatures define the triggering of very simple and specific events that govern all the biochemical interactions of the biomolecule: activation of rigid rotors ($T<T^{*}$), phonon-phonon interactions with phonons of water dimer ($T^{*}<T<T_{D}$), and water rotational barriers surpassing ($T>T_{D}$).Comment: 4 pages, 4 figures, submitted to Physical Review Letter

New insights on mechanisms of sulfonamide bio-transformation by environmental bacteria

info:eu-repo/semantics/publishedVersio