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In this paper, we investigate a class of nonlinear MIMO systems based on prescribed-time sliding mode control (PTSMC). In an effort to extend the concept of fixed-time theory with capability of handling more practical systems, we have developed a PTSMC based on the free-will arbitrary time (FWAT) principle of stability. We propose the FWAT sliding surfaces to improve the convergence of a nonlinear system, what is known as arbitrary convergence in control theory. According to the proposed sliding surface, the states of a system can reach the sliding surfaces (arbitrary reaching phase) within a given time interval and also can hit the origin within a predefined time (arbitrary sliding phase). Using this method, the overall stabilization time can be adjusted freely to suit the needs of the designer. Furthermore, this control method is capable of being implemented independent of any other system parameters. Lyapunov stability theory shows the stability of the proposed control scheme and the designed sliding surfaces. Finally, the efficiency of the proposed approach is demonstrated by performing on two well-known examples such that it verifies the arbitrary convergence of the designed sliding surfaces for various times in spite of revealing the designed control independency of any initial values. [ABSTRACT FROM AUTHOR]

Daily monitoring of airborne fungal spores was carried out for the first time in Al Khor city, Qatar, using a Hirst type 7-day recording volumetric spore trap, from May 2017 to May 2019. During the sampling period, the annual and monthly fluctuations, as well as intradiurnal variations of airborne fungal spore concentrations, were evaluated. Cladosporium, followed by Alternaria, were the spore types most abundant in the atmosphere of the city, with a strong interannual variability in the atmospheric concentrations being observed. The Annual Spore Integrals (ASIns) were 3334 and 1172 spore * day/m3 (2017–2018), and 6796 and 1538 spore * day/m3 (2018–2019) for Cladosporium and Alternaria, respectively. Total daily spore concentrations showed significantly positive correlations with mean, minimum, and maximum temperatures but significantly negative correlations with relative humidity. However, due to the scarce rainfalls' days, we did not find a statistically significant correlations between Cladosporium and Alternaria spore concentrations and this parameter. Despite this, the spore peaks were strongly related to precipitations that occurred during the previous month. In general, no significant correlations were found with wind speed but, regarding wind direction, the higher percentage of spores were collected when wind blows from the 4th quadrant (NW). According to the intradiurnal pattern, Cladosporium fungal spores displayed their maximum daily concentration during 8:00–10:00 h in the morning, with a second peak in the afternoon, while for Alternaria, the maximum peaks were observed between 08:00 and 14:00 h. Because no consistent previous aerobiological studies exist from Qatar, the aim of this study is to define the seasonality and intradiurnal behaviour of these two airborne fungal spore and the role that, in such arid scene, the meteorological parameters play on the spore concentrations. [ABSTRACT FROM AUTHOR]

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The monolithic silica filters here studied were chemically exfoliated by hydrothermal method to modify their physical–chemical properties and optimize photodegradation of methylene blue dye (MB). XRD results revealed an increase in the α-cristobalite phase when it was exposed to higher hydrothermal temperature. Meanwhile, SEM analyses showed a correlation between surface cracking with increased temperature and reaction time. The exfoliated filters increase the adsorption capacity of the molecule up to 2.5 times and show a degradation efficiency of 94% in 5 h of reaction, maintaining the efficiency at 60% after three cycles. Results show a correlation between photodegradation capacity with the morphological stability of the filter. The efficiency is attributed to the exfoliation and presence of pores in the surface, product of the hydrothermal reaction. Therefore, the use of exfoliated monolithic filters is presented as an innovative alternative for its practicality and reproducibility for the scaling up of water treatment processes. [ABSTRACT FROM AUTHOR]

We describe how one can explicitly obtain all atoms of an arbitrary root-closed monoid, whose quotient group is isomorphic to Z 2 . For this purpose, we solve this task for three special types of such monoids in Theorems 5 and 6, and then transfer these results to the general case. It turns out that all atoms can be obtained from the (regular) continued fraction expansion of the slopes of the bounding rays of the cone, which is spanned by the monoid. [ABSTRACT FROM AUTHOR]

Digital Video Broadcasting Terrestrial (DVB-T) is a standard issued by the European Telecommunications Standards Institute (ETSI). The ETSI also issued some implementation guidelines regarding transmission aspects which include coverage requirements. For broadcasting designers, the main reference for calculating coverage is the recommendations of the International Telecommunication Union-Radiocommunication Sector (ITU-R). However, we are in trouble if we try to use the ITU-R recommendations to meet the ETSI coverage requirements because the latter specify a minimum signal level at the receiver to be guaranteed over 99 % of time whereas the ITU-R recommendations only give a calculation procedure for up to 50 % of the time. The present paper offers a method in order to adapt the ETSI coverage requirements to the ITU-R recommendations, based on a research measurement of the DVB-T signal level received in four different environments over a long period of time. [ABSTRACT FROM AUTHOR]

Drawing on evolutionary realism as a guiding framework and using relevant theoretical bases at macro- (country-), meso- (industry-), and micro- (firm-) levels, we investigate the relative variance explained by each level on selection (non-economic performance) and retention (decertification) of Benefit Corporations (B-Corps). Based on a sample of 5052 observations of certified B-Corps and 1403 observations of decertified B-Corps, relative to the country and industry differences, firm-level differences explain most of the variance in non-economic performance, especially for workers and community impact areas. Industry-level differences explain small differences in customers and environmental performance while country differences do not explain meaningful performance differences. The results also show a similar pattern in relative effects for decertified B-Corps. Our findings point to the value of disaggregating the relative effects of multilevel factors in further understanding drivers of non-economic performance and the decertification of B-Corps. [ABSTRACT FROM AUTHOR]

In many real-world optimization problems, more than one objective plays a role and input parameters are subject to uncertainty. In this paper, motivated by applications in disaster relief and public facility location, we model and solve a bi-objective stochastic facility location problem. The considered objectives are cost and covered demand, where the demand at the different population centers is uncertain but its probability distribution is known. The latter information is used to produce a set of scenarios. In order to solve the underlying optimization problem, we apply a Benders' type decomposition approach which is known as the L-shaped method for stochastic programming and we embed it into a recently developed branch-and-bound framework for bi-objective integer optimization. We analyze and compare different cut generation schemes and we show how they affect lower bound set computations, so as to identify the best performing approach. Finally, we compare the branch-and-Benders-cut approach to a straight-forward branch-and-bound implementation based on the deterministic equivalent formulation. [ABSTRACT FROM AUTHOR]

Archaeologists and epigraphers have long worked in concert across methodological and theoretical differences to study past writing. Ongoing integration of digital technologies into both fields is extending this collaboration's scope by facilitating rapid information exchange, integration of multiple datasets in digital formats, and accumulation and analysis of large datasets. Recent research by the Maya Hieroglyphic Database Project, for example, has deployed social network analysis to correlate ritual practice, discourse, and material culture with political interactions. Similarly, epigraphers and archaeologists of pre-Angkorian and Angkorian Southeast Asia have conducted spatial analysis to illuminate the relationship between economy, human mobility, and land use. Collectively, these examples illustrate how scholars are already using digital technologies for research at larger scales and with more diverse datasets than was previously possible. Moreover, they point to further directions for articulating text, material, and context in future studies of the human past. [ABSTRACT FROM AUTHOR]

The vehicle routing problem (VRP) is one of the challenging problems in optimization and can be described as combinatorial optimization and NP-hard problem. Researchers have used many artificial intelligence techniques in order to try to solve this problem. Among these techniques, metaheuristic algorithms that can perform random search are the most promising because they can be used to find the right solution in the shortest possible time. Therefore, in this paper, the Harris hawks optimization (HHO) algorithm was used to attempt to solve the VRP. The algorithm was applied to 10 scenarios and the experimental results revealed that the HHO had a strong ability to check for and find the best route as compared to other metaheuristic algorithms, namely, simulated annealing and artificial bee colony optimization. The comparison was based on three criteria: minimum objective function obtained, minimum number of iterations required and satisfaction of capacity constraints. In all scenarios, the HHO showed clear superiority over the other methods. [ABSTRACT FROM AUTHOR]

In this paper, we study gapsets and we focus on obtaining information on how the maximum distance between two consecutive elements influences the behaviour of the set. In particular, we prove that the cardinality of the set of gapsets with genus g such that the maximum distance between two consecutive elements is κ is equal to the cardinality of the set of gapsets with genus g + 1 such that the maximum distance between two consecutive elements is κ + 1 , when 2 g ≤ 3 κ . [ABSTRACT FROM AUTHOR]

A numerical semigroup S is cyclotomic if its semigroup polynomial P S is a product of cyclotomic polynomials. The number of irreducible factors of P S (with multiplicity) is the polynomial length ℓ (S) of S. We show that a cyclotomic numerical semigroup is complete intersection if ℓ (S) ≤ 2 . This establishes a particular case of a conjecture of Ciolan et al. (SIAM J Discrete Math 30(2):650–668, 2016) claiming that every cyclotomic numerical semigroup is complete intersection. In addition, we investigate the relation between ℓ (S) and the embedding dimension of S. [ABSTRACT FROM AUTHOR]

The novel coronavirus 2019 (COVID-19) emerges from the Chinese city Wuhan and its spread to the rest of the world, primarily affected economies and their businesses, leading to a global depression. The explanatory and cross-sectional regression approach assesses the impact of COVID-19 cases on healthcare expenditures, logistics performance index, carbon damages, and corporate social responsibility in a panel of 77 countries. The results show that COVID-19 cases substantially increase healthcare expenditures and decrease corporate social responsibility. On the other hand, an increase in the coronavirus testing capacity brings positive change in reducing healthcare expenditures, increased logistics activities, and corporate social responsibility. The cost of carbon emissions increases when corporate activities begin to resume. The economic affluence supports logistics activities and improves healthcare infrastructure. It linked to international cooperation and their assistance to supply healthcare logistics traded equipment through mutual trade agreements. The greater need to enhance global trade and healthcare logistics supply helps minimize the sensitive coronavirus cases that are likely to provide a safe and healthy environment for living. [ABSTRACT FROM AUTHOR]

Purpose of Review: We summarize recent published work concerning assessment and treatment of aphasia in bilingual and multilingual people and review current related models of treatment outcomes. As well, we discuss studies that address the recently debated topic of cognitive processes in bilingual individuals with aphasia, with a focus on the effects of bilingualism on aphasia recovery and its potential protective effects. Recent Findings: Providing assessment and treatment tools that best serve multilingual individuals with aphasia and unpacking the variables and mechanisms that underlie response to treatment have emerged as goals of several recent studies. Additionally, while findings are still contradictory, some empirical studies reported that aphasia may manifest less severely in multilingual individuals and may improve faster compared to in monolingual counterparts. Summary: The findings of recent studies with the focus of aphasia in multilingual individuals are crucial to understanding theoretical and clinical aspects of brain-related language impairment in multilingual people and to the study of language representation and processing in the brain. [ABSTRACT FROM AUTHOR]

International research devoted to the representation of women on bank boards of directors is growing rapidly and consideration of the representative set of publications allows summarizing their results. Information analysis of 104 articles published in international scientific journals reveals their thematic diversity and allows one to establish thematic and geographic biases in this research theme. [ABSTRACT FROM AUTHOR]

The silicon thin films have been deposited using VHF (60 MHz) plasma enhanced chemical vapor deposition (PECVD) process. The influence of the power (10–50 W), used during the deposition, on the silicon thin films properties was studied. The structural transition (different crystalline fraction) along with their variable grain distribution within amorphous silicon matrix has been discussed with the help of optical, electrical and structural measurements. Raman characterization along with photoluminescence (PL), UV-VIS spectroscopy, micro-ellipsometry spectroscopy and Field emission scanning electron microscopy (FESEM) have been performed to recognize the transitions in deposited silicon films including the microstructure mainly related with crystallite fraction and optical constants. FESEM was used to investigate the characteristics and variation in the microstructure. From Raman results, the structural transition from amorphous to micro/nanocrystalline growth occur as indicated by narrow band at 515 cm−1 observed at 10 W applied power deposited film. From these results, it was found that with increasing power, the crystallinity increases and the films are highly crystalline (Xc > 50%) in nature above 20 W applied power. The contribution of nano-sized crystallites increases the crystalline volume fraction from 32 to 84%. The peak observed nearly at 2.0 eV in photoluminescence emission spectra (PL) confirms the presence of nanocrystallites in the deposited films which is well correlated with the band gap values observed from UV-VIS spectroscopy. However, red shift in PL peak energy and decrease in PL intensity observed and are explained in terms of grain boundaries. The shift in refractive index (n) and extinction coefficient (k) were also observed at different power variation. The investigation of spectroscopic ellipsometry result explains the microstructure of deposited film with changes in crystallite sizes and their volume fractions. [ABSTRACT FROM AUTHOR]

In this paper we present and study the ideal duplication, a new construction within the class of the relative ideals of a numerical semigroup S, that, under specific assumptions, produces a relative ideal of the numerical duplication S ⋈ b E . We prove that every relative ideal of the numerical duplication can be uniquely written as the ideal duplication of two relative ideals of S; this allows us to better understand how the basic operations of the class of the relative ideals of S ⋈ b E work. In particular, we characterize the ideals E such that S ⋈ b E is nearly Gorenstein. [ABSTRACT FROM AUTHOR]

For a numerical semigroup ring K[H] we study the trace of its canonical ideal. The colength of this ideal is called the residue of H. This invariant measures how far is H from being symmetric, i.e. how far is K[H] from being a Gorenstein ring. We remark that the canonical trace ideal contains the conductor ideal, and we study bounds for the residue. For 3-generated numerical semigroups we give explicit formulas for the canonical trace ideal and the residue of H. Thus, in this setting we can classify those whose residue is at most one (the nearly Gorenstein ones), and we show the eventual periodic behaviour of the residue in a shifted family. [ABSTRACT FROM AUTHOR]

During 2020, a total of 64 wild boar carcasses were tested for Enterobacteriaceae count (EBC), Salmonella and Yersinia enterocolitica in the abdominal region (i) within 5 h after hunting in the game collection point and (ii) before dressing and processing in the game-handling establishment (GHE) (49 carcasses—average time interval between (i) and (ii): 4.3 days). Because of COVID-19 restrictions, 15 carcasses were transported to a near slaughterhouse (average time interval between (i) and (ii): 2.3 days). Mesenteric lymph nodes (MLNs) were collected and tested for Salmonella and Y. enterocolitica. Results are shown in relation to sampling A (49 carcasses—GHE) and sampling B (15 carcasses—slaughterhouse). Sampling A: EBC median values were (i) 2.51 log10 CFU/cm2 and (ii) 2.79 log10 CFU/cm2. EBC increase between (i) and (ii) was statistically significant (p = 0.001). Salmonella prevalence on carcasses varied from (i) 2.0 to (ii) 6.1%. Sampling B: EBC median values were (i) 3.1 log10 CFU/cm2 and (ii) 3.32 log10 CFU/cm2. EBC increase between (i) and (ii) was not statistically significant (p = 0.191). Salmonella prevalence on carcasses varied from (i) 6.7 to (ii) 0.0%. The prevalence (sampling A + B) of lymphatic Salmonella carriers was 7.8% (5/64). From carcasses and/or MNLs, the serovars Enteritidis, Typhimurium, Agama, Zaiman and Diarizonae O:50 (z) were detected. Y. enterocolitica was never isolated. Long chilling periods prior to wild game processing should be avoided, and carcasses should be tested at GHE rather than after shooting to proper reflect the microbial load of wild boar meat entering the food chain. [ABSTRACT FROM AUTHOR]

Fungi are an important component of ecosystems. Some fungi are widely distributed, while others are limited to certain habitats. Studies based on airborne fungal spores can help to know the geographical distribution of fungi in the territory. Our aim was to show that a gamma probability density function (gpdf) based on a database of 20 airborne fungal spore taxa concentrations in eight localities of Catalonia (NE Spain) for a period of 20 years was a useful tool to map the distribution of these taxa in this region, as well as to establish a general classification on their sporulation through the alpha parameter of the validated model. This allows a more efficient study of the atmospheric dynamics of the different taxa, since the number of taxa is reduced to a representative taxon for each of the categories of the generic classification. In general, the results obtained confirmed that the scale parameter of the gamma distribution changes from year to year, depending on the meteorological conditions, while the shape parameter remains fairly stable. At the temporal scale, airborne fungal spores of Agrocybe sp. showed the highest stability; at the spatial scale, Cladosporium sp. showed the highest stability. Regarding localities, Girona was the station with greater interannual variation, while Barcelona and Vielha showed the lowest. In addition, the results obtained allowed a non-subjective classification of these taxa in five groups, based on the gamma (shape) parameter. The taxa Alternaria sp., Cladosporium sp., Ganoderma sp., Pleospora sp., Leptosphaeria sp., Aspergillus sp.-Penicillium sp. were cosmopolitan and showed a similar behavior across the whole study area, with any of them possible candidates for used in predictive models; airborne fungal spores of Agrocybe sp., Arthrinium sp., Epicoccum sp., Drechslera sp.–Helminthosporium sp., Pithomyces sp., Thelephoraceae, Stemphylium sp., Xylariaceae can be used as meteorological indicators and Agaricus sp., Coprinaceae sp., Torula sp. can be used as indicators of anthropogenic activities. The results obtained could be used to reduce the number of spore taxa analyzed and subsequently develop generic predictive models. [ABSTRACT FROM AUTHOR]

In this article, a quadtree element-free Galerkin method (QEFGM) is proposed for automatically configuring background cells. The QEFGM is then employed in the fracture analysis of a piezoelectric elliptical tube subjected to internal pressure and thermal loading. The stress intensity factor (SIF) is calculated by the QEFGM and the traditional element-free Galerkin method (EFGM). By investigating an internally cracked piezoelectric plate subjected to lateral tension, the error of SIF for the EFGM is 5.17%, and the QEFGM is 1.28% at the crack-to-length ratio ( c / W = 0.25 ). The results show that the error of QEFGM is one-fourth of EFGM, which demonstrates the correctness and superiority of the approach. The QEFGM was then employed in an examination of the system geometry on the SIF in a fractured piezoelectric tube. Fracture analysis was carried out for four ellipses with different axial ratios and three super-ellipses of different powers. The SIF increased with the axial ratio for the ellipses, and increased with the powers for the super-ellipses. In this paper, various physical characteristics analyses of fracture piezoelectric material were carried out under different structure geometries. The presented result is beneficial to the prediction of material life. [ABSTRACT FROM AUTHOR]

Let f 1 (n) , ... , f k (n) be polynomial functions of n. For fixed n ∈ N , let S n ⊆ N be the numerical semigroup generated by f 1 (n) , ... , f k (n) . As n varies, we show that many invariants of S n are eventually quasi-polynomial in n, most notably the Betti numbers, but also the type, the genus, and the size of the Δ -set. The tool we use is expressibility in the logical system of parametric Presburger arithmetic. Generalizing to higher dimensional families of semigroups, we also examine affine semigroups S n ⊆ N m generated by vectors whose coordinates are polynomial functions of n, and we prove that in this case the Betti numbers are also eventually quasi-polynomial functions of n. [ABSTRACT FROM AUTHOR]

In this paper, we present an improved methodology to compute the ω -primality of a numerical semigroup. The approach is based on exploiting the structure of the problem on a resolution method for optimizing a linear function over the set of efficient solutions of a multiple objective integer linear programming problem. The numerical experiments show the efficiency of the proposed technique compared to the existing methods. [ABSTRACT FROM AUTHOR]

The atmosphere is host to a complex electric environment, ranging from a global electric circuit generating fluctuating atmospheric electric fields to local lightning strikes and ions. While research on interactions of organisms with their electrical environment is deeply rooted in the aquatic environment, it has hitherto been confined to interactions with local electrical phenomena and organismal perception of electric fields. However, there is emerging evidence of coupling between large- and small-scale atmospheric electrical phenomena and various biological processes in terrestrial environments that even appear to be tied to continental waters. Here, we synthesize our current understanding of this connectivity, discussing how atmospheric electricity can affect various levels of biological organization across multiple ecosystems. We identify opportunities for research, highlighting its complexity and interdisciplinary nature and draw attention to both conceptual and technical challenges lying ahead of our future understanding of the relationship between atmospheric electricity and the organization and functioning of biological systems. [ABSTRACT FROM AUTHOR]

For the first time, the composition of micromycetes communities was investigated in both photic and aphotic entrance zones of seven caves in Montenegro: Obodska Pećina, Golubinja Pećina, Veluštica Pećina, Vrbacka jama, Jama ER-1, Njegoš Pećina, and an unnamed cave. In total, 72 species of micromycetes were identified: 46 species from illuminated photic zones of the caves, including 43 species on phototrophs, 10 species from the air, 15 species on substrates, and 50 species from unlit aphotic zones, including 35 species from the air and 37 species on substrates. The most frequently isolated species were Acrodontium salmoneum, Aureobasidium pullulans, Cladosporium oxysporum, Mucor racemosus f. racemosus, Penicillium chrysogenum, and Rhizopus stolonifer. The similarity between micromycetes composition of different biotopes was evaluated using the Jaccard index and cluster analysis. The greatest similarity was observed in the communities isolated from the air of the photic zones of the caves. [ABSTRACT FROM AUTHOR]

Genetic programming (GP) is a top performer in solving classification and clustering problems, in general and symbolic regression problems, in particular. GP has produced impressive results and has outperformed human generated results for 76 different problems taken from 22 different fields. There remain a number of significant open issues despite its impressive results. Among them are high computational cost, premature convergence and high error rate. These issues must be addressed for GP to realise its full potential. In this paper a simple and cost effective technique called Difficult First Strategy-GP (DFS-GP) is proposed to address the aforementioned problems. The proposed technique involves pre-processing and sampling steps. In the pre-processing step, difficult to evolve data points by GP from the given data set are marked and in the sampling step, they are introduced in the evolutionary run by using two newly defined sampling techniques, called difficult points first and difficulty proportionate selection. These techniques are biased towards selecting difficult data points during the initial stage of a run and of easy points in the latter stage of a run. This ensures that GP does not ignore difficult-to-evolve data points during a run. Experiments have shown that GP coupled with DFS avoids premature convergence and attained higher fitness than standard GP using same fitness evaluations. Performance of the proposed technique was evaluated on three commonly known metrics, which are convergence speed, fitness and variance in the best results. Our results have shown that the proposed setups had achieved 10–15% better fitness values than Standard GP. Furthermore, the proposed setups had consistently generated better quality solutions on all the problems and utilized 30–50% less computations to match the best performance of Standard GP. [ABSTRACT FROM AUTHOR]

This research aims at providing the scientific evidence of ancient construction practice and production technology on the use locally available geoearth materials and natural herbs, namely kadukkai (Terminalia Chebula), neelamari (Indigofera tinctoria), hibiscus (Rosa sinensis), palm jaggery (Borassus flabellifer), aloe vera (Aloe barbadenis) as specified in ancient palm leaf texts which were adopted at Padmanabhapuram Palace, India for preparing the traditional lime mortars. Six mortar samples of three different mortar typologies (wall, bedding and floor finish) were taken from the Padmanabhapuram Palace for the study. The sampled mortars were characterized using physiochemical analysis as well as modern analytical techniques including XRD, TG-DTA, FT-IR and FESEM-EDX methods. Different binder-to-aggregate ratios was proportioned for wall plaster (1:3), bedding mortar (1:2) and floor finish (1:1) and was confirmed through acid loss analysis. Wall plaster samples indicated the presence of organic protein and polysaccharide spectral peaks substantiated by FT-IR analysis. Organics have played a significant role in the formation of calcium aluminate silicates and carbonate polymorphs to enhance the crystalline hydrated phases observed through XRD and FESEM analyses. The thermal investigation substantiated that calcite decarbonation mostly occurred between 705 and 730 °C. The results apprised the wide use of hydraulic lime with fine-grained aggregate particles, added with fermented organics to produce an environmentally friendly organic mortar to restore the structure. [ABSTRACT FROM AUTHOR]

A numerical semigroup is a submonoid of N with finite complement in N . A generalized numerical semigroup is a submonoid of N d with finite complement in N d . In the context of numerical semigroups, Wilf's conjecture is a long standing open problem whose study has led to new mathematics and new ways of thinking about monoids. A natural extension of Wilf's conjecture, to the class of C -semigroups, was proposed by García-García, Marín-Aragón, and Vigneron-Tenorio. In this paper, we propose a different generalization of Wilf's conjecture, to the setting of generalized numerical semigroups, and prove the conjecture for several large families including the irreducible, symmetric, and monomial case. We also discuss the relationship of our conjecture to the extension proposed by García-García, Marín-Aragón, and Vigneron-Tenorio. [ABSTRACT FROM AUTHOR]

In this expository note, we give a self-contained presentation of the equivalence between the opposite category of commutative monoids and that of commutative, monoid k -schemes that are diagonalizable, for any field k . [ABSTRACT FROM AUTHOR]

Planning and scheduling of operating rooms (ORs) is important for hospitals to improve efficiency and achieve high quality of service. Due to significant uncertainty in surgery durations, scheduling of ORs can be very challenging. In this paper, surgical case scheduling problem with uncertain duration of surgeries in multi resource environment is investigated. We present a two-stage stochastic mixed-integer programming model, named SOS, with the objective of total ORs idle time and overtime. Also, in this paper a two-step approach is proposed for solving the model based on the L-shaped algorithm. Proposing the model in a multi resources environment with considering real-life limitations in academic hospitals and developing an approach for solving this stochastic model efficiently form the main contributions of this paper. The model is evaluated through several numerical experiments based on real data from Hasheminejad Kidney Center (HKC) in Iran. The solutions of SOS are compared with the deterministic solutions in several real instances. Numerical results show that SOS enjoys a better performance in 97% of the cases. Furthermore, the results of comparing with actual schedules applied in HKC reveal a notable reduction of OR idle time and over time which illustrate the efficiency of the proposed model in practice. [ABSTRACT FROM AUTHOR]

Microbial organisms can cause huge crises in decorated caves, as seen in emblematic sites such as Lascaux cave. The preservation of such sites involves understanding the healthy microbial behavior of caves before the damage occurs. Indeed, knowledge of normal cave behavior is a prerequisite to identifying potential imbalance. This study seeks to determine whether models of aerobiological behavior could be identified in several caves of different sizes, ranging from rock shelters to large caves that are open or closed to the public. Aerial rates of fungi and bacteria were monitored over 3 years in nine sites in Dordogne (France). This study revealed that in a context of caves where public visits were carefully managed, fungal and bacterial rates were more affected by the size of the caves than by the opening of sites to the visitors. The study confirmed that large caves can generally be described as "self-purifying caves" as they were strongly affected by the exterior environment at their entry but much less so at locations further inside the cave, while small caves can be described as "non-self-purifying caves" since they were strongly affected by the exterior environment throughout their whole length. The results also highlighted the difficulty to determine a limit value of microbial rates valid for all caves because of the specificities of each one. [ABSTRACT FROM AUTHOR]

Grape wood activated carbon (GWAC) as a cost-effectiveness and nontoxic adsorbent was developed for methylene blue (MB) removal from aqueous solutions. The adsorbent was characterized using SEM, BET, FTIR and pHZPC. Design of experiments, modeling and optimization of data were carried out using central composite design through response surface methodology. The effects of the main variables including initial dye concentration (100–500 mg/L), pH (3–11), contact time (10–90 min) and adsorbent dosage (0.25–12.25 g/L) on the decolorization were investigated using analysis of variance (ANOVA). The efficiency of MB removal increased to more than 98.5% with increasing pH and contact time from 3 to 11 and 10 to 90 min, respectively, under 0.25–12.25 g/L of GWAC. The experimental data were fitted to Langmuir model (R2 = 0.98), and the maximum adsorption capacity (qmax) was 4.82 mg/g. The adsorption kinetics were well described by the pseudo-second order (R2 = 0.9485). This study highlighted grape wood waste as a suitable adsorbent with high efficiency for the removal of methylene blue from water and wastewater. [ABSTRACT FROM AUTHOR]

In Lake Grande de Peñalara, an originally fishless small high mountain lake in the Central Iberian Peninsula, brook trout (Salvelinus fontinalis) was introduced in the 1970s, and then eradicated 30 years later using gillnets. In this study, we investigated the time-course and changes in macroinvertebrates and zooplankton communities, before and after the eradication, by studying their richness and several biological and ecological traits of macroinvertebrates. Macroinvertebrates richness increased from 13 taxa coexisting with fish, up to a maximum of 27 taxa after the eradication. Rare groups usually affected by fish predation, e.g. swimmers in surface and open waters, showed high dispersal and recolonization capabilities, while those with burrowing, interstitial or crawler habits maintained their presence, and even with the presence of fish given their advantage of hiding from being directly sighted by fish. Taxa with affinities for rare habitats within the lake (e.g. macrophyte beds) occasionally appeared 4–6 years after eradication. In contrast, zooplankton assemblage did not significantly change in richness in the 10 years after eradication. No new species of cladocerans or copepods appeared after fish removal, but 4 new rotifer taxa appeared and 5 disappeared. This was apparently more related to a change in water quality or trophic status as a consequence of the fish removal than to the direct effect of fish removal on rotifers. Zooplankters were significantly smaller, on average, before fish eradication rather than later, indicating that the community responded to the change in predation pressure. [ABSTRACT FROM AUTHOR]

Background: Increasing the interval of administration of anti-TNF agents over the duration specified in the data sheet is not common in inflammatory bowel disease (IBD).Aim: To evaluate the outcomes of IBD patients treated with this strategy.Methods: Patients with IBD who were treated with infliximab or adalimumab at intervals > 8 weeks or > 2 weeks, respectively, because of persistent clinical remission, were identified at local databases of the ENEIDA registry (a nationwide registry promoted by the Spanish Working Group in Crohn's disease and Ulcerative Colitis-GETECCU) of two referral centers. Treatment success was considered if patients remained in clinical remission with the same schedule or without biological therapy at the end of follow-up, and if no return to the conventional schedule, dose-escalation, change in biological agent, or a course of systemic corticosteroids or surgery were required.Results: Eighty-five patients were included, 60 treated with infliximab and 25 with adalimumab. The spaced schedule was initiated after a median of 25 months on anti-TNF treatment (IQR 14-49). Throughout a median follow-up of 34 months (IQR 21-47), fifty patients (59%) fulfilled the success criteria of the spaced strategy. No differences were found regarding type of IBD or anti-TNF agent. Baseline C-reactive protein levels and disease duration at the time of starting anti-TNF treatment were the only factors associated with treatment success.Conclusions: Anti-TNF administration at longer intervals than those provided in the data sheet may be an efficacious, convenient, and cheaper treatment option, particularly in patients in whom anti-TNF treatment was initiated early. [ABSTRACT FROM AUTHOR]

The Italian Society of Colorectal Surgery (SICCR) promoted the project reported here, which consists of a position statement of Italian colorectal surgeons to address the surgical aspects of Crohn's disease management. Members of the society were invited to express their opinions on several items proposed by the writing committee, based on evidence available in the literature. The results are presented, focusing on relevant points. The present paper is not an alternative to available guidelines; rather, it offers a snapshot of the attitudes of SICCR surgeons about the surgical treatment of Crohn's disease. The committee was able to identify some points of major disagreement and suggested strategies to improve quality of available data and acceptance of guidelines. [ABSTRACT FROM AUTHOR]

The Italian Society of Colorectal Surgery (SICCR) promoted the project reported here, which consists of a Position Statement of Italian colorectal surgeons to address the surgical aspects of ulcerative colitis management. Members of the society were invited to express their opinions on several items proposed by the writing committee, based on evidence available in the literature. The results are presented, focusing on relevant points. The present paper is not an alternative to available guidelines; rather, it offers a snapshot of the attitudes of SICCR surgeons about the surgical treatment of ulcerative colitis. The committee was able to identify some points of major disagreement and suggested strategies to improve the quality of available data and acceptance of guidelines. [ABSTRACT FROM AUTHOR]

Introduction: Natalizumab (NTZ) can be associated with an opportunistic infection, progressive multifocal leukoencephalopathy (PML), caused by John Cunningham virus (JCV). High titer of anti-JCV antibody (JCV index) in patients treated with NTZ for over 2 years limit it use, leading to treatment discontinuation.Objective: Aim of the study was to investigate the JCV index changes pre, during and post NTZ treatment and describe the trend after a long period of NTZ discontinuation.Methods: Patients with relapsing-remitting multiple sclerosis (RR-MS) treated with NTZ between 2010 and 2018 were enrolled in this retrospective-prospective observational study. Inclusion criteria were: (1) diagnosis of RR-MS according to the McDonald criteria 2010, (2) at least six NTZ administrations, (3) at least two determinations of JCV Index during the follow-up period, (4) NTZ discontinuation period for more than 6 months. JCV index was determined by STRATIFY II. There were three different timepoints: NTZ initiation (T0), NTZ discontinuation (T1) and time after NTZ suspension (T2). Seroconversion was defined as changing status of serum JCV antibody. Main outcomes were the JCV index changes and the rate of seroconversion.Results: At baseline we enrolled 285 patients (208 JCV negative, 67 JCV positive, and 10 not available). There was a statistically significant increase of JCV index during NTZ treatment period (T0 vs T1, p =0.0009) and during NTZ discontinuation period (T1 vs T2, p =0.04). Patients seroconverted to a positive status more frequently during NTZ treatment than after discontinuation (p =0.008). Moreover, patients who shifted to fingolimod (FTY) as exit strategy after NTZ discontinuation, showed a statistically significant increase of JCV index.Conclusion: Our data confirmed that a high percentage of patients shift to or remain in a positive JCV status during NTZ treatment and after discontinuation. NTZ suspension seems not to be able to interfere on JCV status modification over an extended period. The choice of alternative treatment as exit strategy after NTZ discontinuation should be carefully considered because it could negatively influence the PML risk stratification of patients. [ABSTRACT FROM AUTHOR]

In this paper we study those submonoids of N d with a nontrivial pseudo-Frobenius set. In the affine case, we prove that they are the affine semigroups whose associated algebra over a field has maximal projective dimension possible. We prove that these semigroups are a natural generalization of numerical semigroups and, consequently, most of their invariants can be generalized. In the last section we introduce a new family of submonoids of N d and using its pseudo-Frobenius elements we prove that the elements in the family are direct limits of affine semigroups. [ABSTRACT FROM AUTHOR]

Groundwater is the major water source in arid and semi-arid regions and its availability under future climatic scenarios is uncertain. In this context, the knowledge of the likely changes in aquifer recharge is very important for sustainable management of groundwater resources in these environments. This work assesses the effect of future potential changes in the climate variables on aquifer recharge in a Mediterranean semi-arid aquifer (Sierra de Las Aguilas (SAG), SE Spain). We used monthly piezometric data to validate the aquifer recharge simulated by HYDROBAL ecohydrological model over the period 2001–2016. This model was then used to simulate the aquifer recharge over the historical period 1971–2000 and over two projected periods (2039–2068 and 2069–2098) using 18 downscaled climate projections. The results show that the percentage of aquifer recharge to precipitation (PAR) decreased significantly over the historical period (− 0.3% year−1, p < 0.05). This decreasing tendency is expected to continue in the same direction with similar reduction rate (− 0.4% year−1, p < 0.001) under the moderate RCP4.5 climate scenario and with a higher rate (− 0.6% year−1, p < 0.001) under the high RCP8.5 scenario. These changes, due principally to the reduction of precipitations, will inverse the recuperation trend observed in the water level. Actually, the current water pumping from the SAG aquifer represents 10% of precipitation below the observed PAR (15.1%). However, in the future, the PAR is expected to decrease below the 10% threshold under the two RCP scenarios for the medium- and long-term periods. [ABSTRACT FROM AUTHOR]

Alternaria and Cladosporium are the most common airborne fungal spores responsible for health problems, as well as for crop pathologies. The study of their behavior in the air is a necessary step for establishing control and prevention measures. The aim of this paper is to develop a logistic regression model for predicting the daily concentrations of airborne Alternaria and Cladosporium fungal spores from meteorological variables. To perform the logistic regression analysis, the concentration levels are binarized using concentration thresholds. The fungal spore data have been obtained at eight aerobiological monitoring stations of the Aerobiological Network of Catalonia (NE Spain). The meteorological data used were the maximum and minimum daily temperatures and daily rainfall provided by the meteorological services. The relationship between the meteorological variables and the fungal spore levels has been modeled by means of logistic regression equations, using data from the period 1995–2012. Values from years 2013–2014 were used for validation. In the case of Alternaria, three equations for predicting the presence and the exceedance of the thresholds 10 and 30 spores/m3 have been established. For Cladosporium, four equations for the thresholds 200, 500, 1000, and 1500 spores/m3 have been established. The temperature and cumulative rainfall in the last 3 days showed a positive correlation with airborne fungal spore levels, while the rain on the same day had a negative correlation. Sensitivity and specificity were calculated to measure the predictive power of the model, showing a reasonable percentage of correct predictions (ranging from 48 to 99%). The simple equations proposed allow us to forecast the levels of fungal spores that will be in the air the next day, using only the maximum and minimum temperatures and rainfall values provided by weather forecasting services. [ABSTRACT FROM AUTHOR]

Actuators, sensors, micro- and nano-electromechanical systems and other piezoelectirc components are generally constructed in block form or as a thin laminated composites. The study of the integrity of such materials in their various forms and small sizes is still a challenge nowadays. To gain a better understanding of these systems, this work presents a crack surface contact formulation that includes friction and thus makes it possible to study the integrity of these advanced materials under more realistic crack surface multifield operational conditions. The dual boundary element method (BEM) is used for modeling frictional crack surface contact on piezoelectric solids in the presence of electric fields, further taking into account the electrical semipermeable boundary conditions on the crack. The formulation uses contact operators over the augmented Lagrangian to enforce contact constraints on the crack surfaces. The BEM reveals to be a very suitable methodology for these interface interaction problems because it considers only the boundary degrees of freedom, what makes it possible to reduce the number of unknowns and to obtain accurate results with a much lower number of elements than formulations based on the standard finite element method or the eXtended finite element method. The capabilities of this methodology are illustrated by solving some benchmark problems. [ABSTRACT FROM AUTHOR]

In this paper, we present new analytical solutions for modified polarization saturation (PS) models for arbitrary polarized and semipermeable 2-D piezoelectric media. The PS model is modified to various other non-linear fracture models by varying the normal electric displacement saturated conditions in place of a constant saturated value. These variations are hereby defined as interpolating linear, quadratic and cubic type's polynomials into saturated value interpolated on the basis of possible electric displacement values at the centre of the crack, actual crack tip and saturated zone tip. To present the analytical study, a centre crack problem in 2-D semipermeable piezoelectric media under arbitrary poling direction and combined in-plane mechanical and electric displacement loadings is considered. Using extended Stroh formalism and complex variable approach, these models are mathematically reduced into generalized non-homogeneous Riemann–Hilbert problems. Applying Riemann–Hilbert technique, the solution of these problems is obtained in terms of generalized complex potential functions representing traction forces and electric displacement components. These lead to obtain the explicit expressions for saturated zone length, crack opening displacement, crack opening potential and local intensity factor in each case. Also, the results of saturation zones and local intensity factor are obtained in each case and compared with the established numerical results. The studies show that saturated zone length increases with increasing electric loading for each case and also depends on the polynomial varying saturation condition. For a particular electric loading applied within the range of critical value, it increases with increasing degree of polynomial type saturated condition i.e. from constant to cubic type's normal electric displacement saturated condition. [ABSTRACT FROM AUTHOR]

Aim: To assess the clinical benefits of transmural healing (TH) shown on intestinal ultrasound (IUS) after treatment with tumor necrosis factor-alpha antibodies (anti-TNF) in patients with Crohn's disease.Materials and Methods: This prospective study included consecutively 36 patients who underwent IUS in the week prior to start anti-TNF treatment, at 12 weeks, and 1 year after starting treatment. The clinical response to treatment was assessed using the Crohn's disease activity index and C-reactive protein (CRP) values. TH was defined as the normalization of bowel wall thickness on IUS. Treated patients were considered to have a good outcome if none of the following situations presented: need to reintroduce corticosteroids or intensify maintenance therapy and/or need for surgery.Results: After the induction regimen, 29 patients (80.6%) achieved clinical remission, and serum CRP values returned to normal in 20 patients (55.6%). In the IUS at 12 weeks, treatment induced a statistically significant reduction in the wall thickness (p < 0.001) and color Doppler grade (p < 0.001), as well as resolution of complications in 66.7% of patients (p < 0.03). IUS after 1 year of biological therapy showed TH in 14/33 patients (42.4%). During the follow-up (median 48.5 months), 23 of the 33 (69.7%) patients in remission or response after induction therapy presented a good outcome. Sonographic TH was significantly related with better outcomes, with only 1/14 patients having a poor outcome compared to 9/19 without TH (OR 11.7, 95% CI 1.2-108.2 p = 0.01, Chi-squared test).Conclusion: Patients who achieve TH on IUS with biological treatment have better clinical outcomes. [ABSTRACT FROM AUTHOR]

Given a numerical semigroup ring R = k 〚 S 〛 , an ideal E of S and an odd element b ∈ S , the numerical duplication S ⋈ b E is a numerical semigroup, whose associated ring k 〚 S ⋈ b E 〛 shares many properties with the Nagata's idealization and the amalgamated duplication of R along the monomial ideal I = (t e ∣ e ∈ E) . In this paper we study the associated graded ring of the numerical duplication characterizing when it is Cohen–Macaulay, Gorenstein or complete intersection. We also study when it is a homogeneous numerical semigroup, a property that is related to the fact that a ring has the same Betti numbers of its associated graded ring. On the way we also characterize when gr m (I) is Cohen–Macaulay and when gr m (ω R) is a canonical module of gr m (R) in terms of numerical semigroup's properties, where ω R is a canonical module of R. [ABSTRACT FROM AUTHOR]

Percutaneous ultrasonography (perc-US) and magnetic resonance enterography (e-MR) are the present standards for staging patients with Crohn's disease (CD). However, intraoperative data still have some discrepancies with preoperative ones. The contribution of intraoperative ultrasonography (IOUS) has never been evaluated. Sixty-five consecutive patients scheduled for ileal/colonic resection for CD between 2010 and 2014 were prospectively enrolled. All patients had perc-US, e-MR and IOUS. Data from different imaging modalities were compared. The reference standard was the final pathology. Surgery was scheduled because of intestinal obstruction (n = 31 patients), inflammatory mass (n = 21), fistula (n = 10), or abdominal pain/sepsis (n = 3). Fourteen (21.5%) patients had a major discrepancy between preoperative and intraoperative data that required a modification of the surgical planning (five additional ileal lesions, three unknown ileo-sigmoid fistulas, and six not confirmed CD sites). IOUS correctly staged CD in all but one patients (missed ileo-colonic fistula). Pathology data differed from Perc-US data in 13 (20%) patients, from e-MR data in 14 (21.5%), and from IOUS data in one (1.5%). The sensitivity of Perc-US, e-MR and IOUS was: for the identification of CD sites 84.2%, 86.1%, and 100%; for the identification of stenoses 86.8%, 86.8%, and 100%; for the identification of fistulas 75.0%, 81.3%, and 93.8%, respectively. IOUS contributed to the surgical planning in 8 (12.3%) patients. IOUS is a safe, feasible and easy-to-perform procedure that optimizes staging of CD and, in some patients, helps to better define the treatment strategy. It could be helpful to face complex disease presentations on the basis of objective and reproducible data. [ABSTRACT FROM AUTHOR]

We find a relation between the genus of a quotient of a numerical semigroup S and the genus of S itself. We use this identity to compute the genus of a quotient of S when S has embedding dimension 2. We also exhibit identities relating the Frobenius numbers and the genus of quotients of numerical semigroups that are generated by certain types of arithmetic progressions. [ABSTRACT FROM AUTHOR]