The stable marriage problem with restricted pairs Dias, Vânia M.F.; da Fonseca, Guilherme D.; de Figueiredo, Celina M.H. ...
Theoretical computer science,
09/2003, Letnik:
306, Številka:
1-3
Journal Article
Recenzirano
Odprti dostop
A stable matching is a complete matching of men and women such that no man and woman who are not partners both prefer each other to their actual partners under the matching. In an instance of the ...STABLE MARRIAGE problem, each of the n men and n women ranks the members of the opposite sex in order of preference. It is well known that at least one stable matching exists for every STABLE MARRIAGE problem instance. We consider extensions of the STABLE MARRIAGE problem obtained by forcing and by forbidding sets of pairs. We present a characterization for the existence of a solution for the STABLE MARRIAGE WITH FORCED AND FORBIDDEN PAIRS problem. In addition, we describe a reduction of the STABLE MARRIAGE WITH FORCED AND FORBIDDEN PAIRS problem to the STABLE MARRIAGE WITH FORBIDDEN PAIRS problem. Finally, we also present algorithms for finding a stable matching, all stable pairs and all stable matchings for this extension. The complexities of the proposed algorithms are the same as the best known algorithms for the unrestricted version of the problem.
We review our experience and the literature in treating 4 patients with Wilms' tumor (WT) with intracardiac extension among 92 patients with this neoplasm. Cardiopulmonary bypass with circulatory ...arrest and profound hypothermia was used. There were 3 boys (3 years, 4 years 5 months, and 15 years) and 1 girl (6 years). The follow-up periods were 8 months, 3 years, 2 years 6 months, and 15 years, respectively. We had no surgical complications and conclude that the preoperative diagnosis is extremely important. These patients must be transferred to institutions where concomitant cardiac procedures can be performed. In treating patients with WT, Doppler ultrasound must be used preoperatively in all cases, not only those in which clinical and radiologic signs of intravascular involvement are found. We propose that preoperative chemotherapy should be used, as it shrinks the thrombus and causes desirable adherence of the thrombus to the venous wall, reducing the probability of thromboembolism during the surgical procedure. We also find this method safer than in our 1st case, where neither cardiac arrest nor hypothermia was used. Our results agree with the literature that intracardiac extension of WT does not worsen its prognosis when a rational surgical approach is used.
Biopharmaceuticals are innovative solutions that have revolutionized the treatment of important chronic diseases and malignancies. The approval of biosimilar products has become a complex and ...balanced process, and there are versions of drugs with established biosimilarity that can offer a more accessible treatment option to patients. The objective of this work was to identify the advancement of these technologies by means of patent and article analysis based on technological and scientific prospection. In patent document recovery, Derwent Innovation Index (DWPI) and PatentInspiration databases were used. The research was based on the search of the selected terms in the title, summary, and claims of the documents through a search strategy containing IPC code and keywords. In articles recovery, the Web of Science tool was used in the search of scientific publications dated from the last 5 years. The search resulted in a total of 2295 individual patent documents and 467 families using DWPI database, 769 individual patents and 205 families using PatentInspiration, and 2602 articles using Web of Science database. Additionally, this work describes the number of organizations that contribute to this area, where they are, how much development they have undergone, and the inventors/authors involved. Based on the number of publications registered, there is an important prominence for scientific research in mAbs. In terms of innovation, it is expected that several therapeutic drugs are already under regulatory review, which will allow drugs to be approved over the next few years and will thus generate a continuous flow of new products based on immunotherapies, mAbs, and biosimilar drugs. These drugs have become essential weapons for the treatment of significant diseases, and the increasing trend in the number of related scientific and technological publications contributes to making these therapies available to the greatest number of people.
The seagrass of Perezoso (Cahuita National Park, Caribbean coast of Costa Rica) was monitored using the CARICOMP protocol. Productivity (2.7 +/- 1.15 g/m2/d; n=74) was intermediate, compared to other ...Caribbean sites. Total biomass was intermediate to high (750-1500 g/m2) at most CARICOMP sites (Colombia, Cuba, Mexico, Puerto Rico and Venezuela) including Costa Rica (822.8 +/- 391.84 g/m2; n=32). Turnover rates were high (5.5 +/- 1.36%; n=74) compared to what was found in March and August at other sites. Shoot densities average 725 shoots/m2, in the Caribbean region, while in Costa Rica the value was higher (1184 +/- 335.5 shoots/m2). Average leaf length and width in the entire region were 14.4 cm and 10.6 mm, respectively, similar to what we found, but leaf area index average 3.4 m2 m(-2), higher than what was found in Costa Rica (0.92 m2 m(-2)). At Cahuita, seagrass productivity was significantly lower in March 2005 compared with the previous six years, and biomass has decreased with time. Seagrass productivity and biomass are being affected by the maximum temperatures, which increased by almost 10 degrees C from 1999 to 2005, and show a high negative correlation. Turnover rate and temperature were not correlated. Recreational boating, swimming and nutrient loading from deforested lands in the coast, the upstream rivers and local pollution are potential sources of impact to the seagrass beds at Cahuita.
► The processing conditions of chitosan electrospun mats are investigated. ► The conditions for obtaining reproducible mats with uniform fibers are presented. ► Fiber diameter is affected by the ...solution and the distance to the collector. ► Needle diameter and feed rate do not have influence in the chitosan mats. ► Electrospinning does not influence the degree of deacetylation of the polymer.
The production of chitosan nanofiber mats by electrospinning presents serious difficulties due to the lack of suitable solvents and the strong influence of processing parameters on the fiber properties. Two are the main problems to be solved: to control the properties of the solution in order to obtain large area uniform fiber mats by having a stable flow rate and to avoid sparks during the process, damaging the fiber mats. In this work chitosan electrospun mats have been prepared form solutions of trifluoroacetic acid/dichloromethane mixtures, allowing solving the aforementioned problems. Mats with uniform fibers of submicron diameters without beads were obtained. Further, the influence of the different solution and process parameters on the mean fiber diameter and on the width of the distribution of the fiber sizes has been assessed. Solvent composition, needle diameter, applied voltage and traveling distance were the parameters considered in this study.
Anaerobic sludge granulation was evaluated in an expanded granular sludge bed (EGSB) reactor based on the increases in the specific organic loading rate (SOLR). The effect of precursor substances ...(calcium chloride, sodium chloride, and tannin) on the development of granular sludge was also investigated in batch reactors. The reactors were fed with synthetic sewage and operated in mesophilic conditions. The EGSB was operated with a variable hydraulic retention time (HRT) and the batch reactors, with cycles of 8 h and 16 h. The increase of SOLR from 17.4 ± 7.4 to 104.6 ± 66.7 mgCOD gVSS-1 d-1 in the EGSB resulted in an increase on the average granules diameter from 344.3 to 1583.3 μm. These conditions also favored the reduction rates of chemical oxygen demand (COD) and volatile fatty acids (VFAs) concentration in the reactor. When the upflow velocity suffered an abrupt increase (from 0.06 L h-1 to 0.25 L h-1), the granules size began to decrease and lose their settleability characteristics. Considering this, it is proposed to start the biomass granulation process without effluent recirculation, and, after the granules reach the desired size and settleability capacity, the normal operation of EGSB reactor starts. The results showed that calcium chloride was more efficient for granulation. CaCl2 addition can be performed only during the reactor's start-up, improving granulation and reducing start-up time. Thus, these results have practical implications as granules maintenance is the key to the proper EGSB operation.
•High upflow velocity decreases the granules' size in the start-up of the EGSB.•It is recommended to start the sludge granulation in UASB-type reactors.•The increase in the size of the granules favored COD removals.•Calcium chloride can be used as precursor agent for anaerobic sludge granulation.
The positive Ti isotope versus SiO2‐content correlation in igneous rocks reflects the fractional crystallization of Ti‐bearing oxide minerals. However, Ti isotope variations of subduction‐related ...igneous rocks indicate that the Ti isotope compositions of their mantle sources are heterogeneous and additional mineral phases may promote Ti isotope fractionation. We have determined the Ti isotope composition of well‐characterized subduction‐related basalts, andesites and boninites. Samples from the Solomon Islands, the Troodos ophiolite in Cyprus, and Cape Vogel in Papua New Guinea show small but resolvable variations that may be related to differences in their mantle sources. Specifically, the δ49Ti of boninites (+0.109‰ to +0.168‰) is slightly higher than that of tholeiites (−0.027‰ to +0.111‰) from the same localities (Troodos in Cyprus and Cape Vogel in Papua New Guinea). Modeling suggests the partial melting of progressively depleted mantle sources where residual Cr‐spinel plays a greater role in controlling the Ti budget during partial melting. More pronounced variations in δ49Ti are clearly linked to the fractional crystallization of Ti‐oxides: Samples from Rabaul Volcanic Complex (New Britain, Papua New Guinea) show increasing δ49Ti (up to +0.373‰) with increasing Ti/V and decreasing Dy/Yb. Fractional crystallization models suggest that oxide minerals and amphibole are needed to sufficiently increase the δ49Ti of these magmas. Our study highlights that the combination of diagnostic trace element patterns and Ti isotope compositions in subduction‐related igneous rocks can be a powerful tool to constrain petrogenetic processes and to discriminate between different crystallizing mineral phases.
Plain Language Summary
Titanium isotope data obtained for basalts from various volcanic arc‐related settings show how the different minerals involved in their magmatic evolution influence their Titanium isotope composition. Coupled with trace element concentration data, magmatic processes are revealed that operate on either a large scale, such as along the arc in the 10 km range, or as very specific magma chamber processes.
Key Points
Mass‐dependent Titanium isotope variations in arc basalts originate from fractional crystallization as well as partial melting
Trace element and isotope modeling strongly suggest that amphibole fractionates Ti isotopes in addition to magnetite or ilmenite
FRB 20180916B is a well-studied repeating fast radio burst source. Its proximity (~150 Mpc), along with detailed studies of the bursts, have revealed many clues about its nature -- including a ...16.3-day periodicity in its activity. Here we report on the detection of 18 bursts using LOFAR at 110-188 MHz, by far the lowest-frequency detections of any FRB to date. Some bursts are seen down to the lowest-observed frequency of 110 MHz, suggesting that their spectra extend even lower. These observations provide an order-of-magnitude stronger constraint on the optical depth due to free-free absorption in the source's local environment. The absence of circular polarization and nearly flat polarization angle curves are consistent with burst properties seen at 300-1700 MHz. Compared with higher frequencies, the larger burst widths (~40-160 ms at 150 MHz) and lower linear polarization fractions are likely due to scattering. We find ~2-3 rad/m^2 variations in the Faraday rotation measure that may be correlated with the activity cycle of the source. We compare the LOFAR burst arrival times to those of 38 previously published and 22 newly detected bursts from the uGMRT (200-450 MHz) and CHIME/FRB (400-800 MHz). Simultaneous observations show 5 CHIME/FRB bursts when no emission is detected by LOFAR. We find that the burst activity is systematically delayed towards lower frequencies by ~3 days from 600 MHz to 150 MHz. We discuss these results in the context of a model in which FRB 20180916B is an interacting binary system featuring a neutron star and high-mass stellar companion.
•An overview of origami-inspired systems and structures is presented discussing the fundamentals, applications and modeling.•The construction of origami reduced-order models based on kinematic-based ...approach and symmetry hypotheses is discussed.•Kinematic-based approach is treated using either equivalent mechanisms or direct geometric analysis, establishing a procedure to build reduced-order models based on rigid origami theory.•Finite element analysis (FEA) is discussed for a complete investigation including panel deformations during folding process, furnishing a range of validity for reduced-order models.•Nonlinear dynamics of origami systems is discussed as an application of the use of reduced-order models showing rich and complex behaviors.
Origami is inspiring several fields of knowledge such as engineering, aerospace systems, medicine, and biomechanics, motivating the creation of novel adaptive and morphing systems and structures where smart materials are employed for actuation. The combination of low energy processes and inherent foldability allows the design of optimized systems widely applicable, ranging from nanoscale to megascale. This article deals with a general overview of the mechanical description of origami-inspired systems and structures, discussing their fundamentals, applications and modeling approaches. A critical review of the mechanical modeling is discussed considering either kinematic-based or mechanic-based formulations. A collection of results is reported to allow a comparison of the best strategies to deal with the complex behavior of origami systems and structures. Kinematic-based formulations are presented with a special interest on developing reduced-order models. Equivalent mechanisms and direct geometric approaches are treated exploring symmetry hypotheses as the basis to build proper reduced-order models. Mechanic-based formulations are treated as a reference description using finite element analysis. The comparison of the different descriptions allows one to establish reduced-order model range of validity, which is a powerful tool for design purposes. Nonlinear dynamics of origami systems and structures are reviewed exploiting the use of reduced-order models. A rich and complex behavior originated from the combination of geometrical and constitutive nonlinearities is stated.
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