Solving satisfiability problems by fluctuations: The dynamics of stochastic local search algorithms

Stochastic local search algorithms are frequently used to numerically solve hard combinatorial optimization or decision problems. We give numerical and approximate analytical descriptions of the dynamics of such algorithms applied to random satisfiability problems. We find two different dynamical regimes, depending on the number of constraints per variable: For low constraintness, the problems are solved efficiently, i.e. in linear time. For higher constraintness, the solution times become exponential. We observe that the dynamical behavior is characterized by a fast equilibration and fluctuations around this equilibrium. If the algorithm runs long enough, an exponentially rare fluctuation towards a solution appears.Comment: 21 pages, 18 figures, revised version, to app. in PRE (2003

Scientific and technological developments in mating disruption of scale insects

[EN] Mating disruption (MD) is a species-specific and environmentally friendly pest management tactic based on the release of synthetic sex pheromones aiming to interrupt the mate-finding communication and prevent mating in the target pest. The present work aims to provide an overview of the current scientific and technical knowledge on mating disruption of scale pests (Hemiptera: Coccoidea). Biparental scales are suitable targets for mating disruption (technically, MD is not suitable for parthenogenetic scales), as the females have a limited spreading ability, and adult males are short lived and have a narrow window of time for mate searching. In this perspective, delayed mating also plays an important role by reducing female attractiveness and population growth potential. The mechanisms involved in MD of scales are most likely assigned to `competitive disruption¿ rather than `noncompetitive¿ mechanisms, although no specific studies addressed this issue. Mating disruption has been commercially developed and increasingly applied against the vine mealybug Planococcus ficus (Signoret) (Hemiptera: Pseudococcidae) and the California red scale Aonidiella aurantii (Maskell) (Hemiptera: Diaspididae) to a lesser extent. Critical factors affecting MD effectiveness are the pest density and effective disruption late in the season. Mating disruption applied to scale pests is effective in small plots and compatible with biological control and integrated management programs. In conclusion, MD has a high potential for management of scale pests, providing that key factors such as technological advances in pheromone synthesis and pheromone formulations, elucidation of disruption mechanisms, and simplification of the registration process are addressed.The authors wish to thank Alejandro Carbonell and Teresa Gadea (EPA, Ecologia y Proteccion Agricola SL), Ignacio de Alfonso (Suterra LCC), David Haviland (University of California), and Vittorio Veronelli (CBC Europe) for providing insightful information on the application and spread of mating disruption. Funding was provided by Fundacao para a Ciencia e a Tecnologia I.P., Portugal, to Centro de Estudos Florestais (UIDB/00239/2020), and by the University of Catania in the framework of the research project `Emergent pests and pathogens and relative sustainable strategies -5A722192113'.Franco. José Carlos; Cocco, A.; Lucchi, A.; Mendel, Z.; Suma, P.; Vacas, S.; Mansour, R.... (2022). Scientific and technological developments in mating disruption of scale insects. Entomologia Generalis. 42(2):251-273. https://doi.org/10.1127/entomologia/2021/1220S25127342

INSECT PESTS OF EUCALYPTUSPLANTATIONS IN SARDINIA (ITALY)

In Sardinia (Italy), Eucalyptusplantations cover approximately 23,000 hectares, above all in the southern part ofthe island. There is a complex of phytophagous insect pests that is threatening the health status of Eucalyptustrees. Themost recent invasions include the sap-suckers, Glycaspis brimblecombei, Blastopsylla occidentalis, and the bronze bug,Thaumastocoris peregrinus. Other pest species have also been reported, including the gall wasps, Ophelimus maskelliand Leptocybe invasa, the longhorn beetles, Phoracantha semipunctataand P. recurva, and the weevils, Gonipterusscutellatusand Polydrusus(= Metallites) parallelus. Defoliation caused by the gypsy moth, Lymantria dispar, have alsobeen frequently observed in various Eucalyptus-planted areas of Sardinia

L-dopa and dopamine-(R)-alpha-lipoic acid conjugates as multifunctional codrugs with antioxidant properties

A series of multifunctional codrugs (1-4), obtained by joining L-Dopa (LD) and dopamine (DA) with (R)-R-lipoic acid (LA), was synthesized and evaluated as potential codrugs with antioxidant and iron-chelating properties. These multifunctional molecules were synthesized to overcome the pro-oxidant effect associated with LD therapy. The physicochemical properties, together with the chemical and enzymatic stabilities of synthesized compounds, were evaluated in order to determine both their stability in aqueous medium and their sensitivity in undergoing enzymatic cleavage by rat and human plasma to regenerate the original drugs. The new compounds were tested for their radical scavenging activities, using a test involving the Fe (II)- H2O2-induced degradation of deoxyribose, and to evaluate peripheral markers of oxidative stress such as plasmatic activities of superoxide dismutase (SOD) and glutathione peroxidase (GPx) in the plasma. Furthermore, we showed the central effects of compounds 1 and 2 on spontaneous locomotor activity of rats in comparison with LD-treated animals. From the results obtained, compounds 1-4 appeared stable at a pH of 1.3 and in 7.4 buffered solution; in 80% human plasma they were turned into DA and LD. Codrugs 1-4 possess good lipophilicity (log P > 2 for all tested compounds). Compounds 1 and 2 seem to protect partially against the oxidative stress deriving from auto-oxidation and MAO-mediated metabolism of DA. This evidence, together with the “in vivo” dopaminergic activity and a sustained release of the parent drug in human plasma, allowed us to point out the potential advantages of using 1 and 2 rather than LD in treating pathologies such as Parkinson’s disease, characterized by an evident decrease of DA concentration in the brain

Road traffic pollution and childhood leukemia: a nationwide case-control study in Italy

Background The association of childhood leukemia with traffic pollution was considered in a number of studies from 1989 onwards, with results not entirely consistent and little information regarding subtypes. Aim of the study We used the data of the Italian SETIL case-control on childhood leukemia to explore the risk by leukemia subtypes associated to exposure to vehicular traffic. Methods We included in the analyses 648 cases of childhood leukemia (565 Acute lymphoblastic–ALL and 80 Acute non lymphoblastic-AnLL) and 980 controls. Information on traffic exposure was collected from questionnaire interviews and from the geocoding of house addresses, for all periods of life of the children. Results We observed an increase in risk for AnLL, and at a lower extent for ALL, with indicators of exposure to traffic pollutants. In particular, the risk was associated to the report of closeness of the house to traffic lights and to the passage of trucks (OR: 1.76; 95% CI 1.03–3.01 for ALL and 6.35; 95% CI 2.59–15.6 for AnLL). The association was shown also in the analyses limited to AML and in the stratified analyses and in respect to the house in different period of life. Conclusions Results from the SETIL study provide some support to the association of traffic related exposure and risk for AnLL, but at a lesser extent for ALL. Our conclusion highlights the need for leukemia type specific analyses in future studies. Results support the need of controlling exposure from traffic pollution, even if knowledge is not complete

Condições de trabalho em unidades hospitalares COVID-19: percepções de trabalhadores de enfermagem

Objetivo: Conhecer as percepções de trabalhadores de enfermagem acerca de suas condições de trabalho em unidades hospitalares COVID-19.Método: Estudo qualitativo, descritivo, multicêntrico, realizado setembro de 2020 e julho de 2021 com 35 trabalhadores de enfermagem de unidades COVID-19 de sete hospitais do Rio Grande do Sul, Brasil. Os dados foram produzidos por meio de entrevistas semiestruturadas e submetidos à análise temática de conteúdo com auxílio do software NVivo.Resultados: Os participantes referiram disponibilidade de recursos materiais e equipamentos de proteção individual, mas percebiam carências de recursos humanos, de suporte multiprofissional e absorção extra de tarefas, resultando na intensificação do trabalho e culminando em sobrecarga. Aspectos profissionais e institucionais também foram referidos, como fragilidade na autonomia profissional, defasagem salarial, atrasos nos pagamentos e pouca valorização institucional.Conclusão: Os trabalhadores de enfermagem das unidades COVID-19 conviveram com a precarização das condições de trabalho, agravadas por elementos organizacionais, profissionais e financeiros. Palavras-chave: Enfermagem. COVID-19. Condições de trabalho. Profissionais de enfermagem. Unidades hospitalares

Evaluation of a novel human IgG1 anti-claudin3 antibody that specifically recognizes its aberrantly localized antigen in ovarian cancer cells and that is suitable for selective drug delivery

Membrane protein claudin3 has been recently suggested as a marker for biologically aggressive tumors and a possible target for the therapeutic delivery of active anti-cancer compounds. Claudin3-binding molecules such as the Clostridium perfringens enterotoxin (CPE), CPE-related molecules, and murine and chimeric antibodies have shown promising antitumor efficacy in preclinical oncological settings. We first engineered a fully human anti-claudin3 IgG1 antibody (IgGH6) by fusing the human IgG1 Fc-domain to the anti-claudin3 scFvH6 previously isolated from a pre-immune phage display library. The construct was expressed in mammalian cells and specifically targeted claudin3 endogenously expressed on the surface of different human ovarian cancer cell lines. No detectable cross-reactivity with other homologous claudins was observed. The epitope recognized by IgGH6 is located within the minor extracellular domain of claudin3 and becomes accessible only in tumor cells characterized by incomplete junction formation. Confocal microscopy experiments demonstrated that IgGH6 was actively internalized in tumor cells after binding to native claudin3 and co-localized, likely within intracellular vesicles, with the C-CPE peptide. Preliminary results indicate that IgGH6 accumulated in vivo in free claudin3 ovarian carcinoma xenografts. For its selective uptake in tumor cells and its human nature, IgGH6 represents a valuable candidate for antibody-drug conjugate therapeutic applications in ovarian cancer patients

EVALUATION OF THE EPIDEMIOLOGY OF EXPOSED FRACTURES BEFORE AND DURING THE COVID-19 PANDEMIC

ABSTRACT Objective: To assess the impact of the COVID-19 pandemic on the epidemiology and clinical outcomes of open fractures considering the periods before and during the pandemic. Methods: An observational and retrospective study, which included patients aged over 18 years, admitted to the Orthopedics and Traumatology Ward of Hospital São Paulo, of the Federal University of São Paulo (UNIFESP). Data was collected in two moments: pre-pandemic (March 1, 2019, to February 29, 2020) and during the pandemic (March 1, 2020, to February 28, 2021). Results: In total, 183 patients were evaluated with a mean age of 36 years ± 14 years. In the pre-pandemic period, 94 patients underwent surgery, 81 men (85.37%) and 13 women (14.2%), with a mean age of 36 ± 3 years. During the pandemic period, 89 patients were subjected to surgery, 77 men (86.6%) and 12 women (13.4%), with a mean age of 38 ± 3 years. Conclusion: During the pandemic, open fractures were still more common in men. Regarding hospital indicators, the prevalence of infections in the surgical wound and the length of stay of patients with open fractures increased, however, with little significance. Fractures classified as Gustilo IIIA were the most common, while the most common according to the AO classification were 33, 34, 42, 43, 2R3, and 2R3 + 2U2. The frequency of run overs during the pandemic decreased. However, firearm projectile injuries and falls and occupational injuries increased. Level of Evidence III, Retrospective Comparative Study

On the freezing of variables in random constraint satisfaction problems

The set of solutions of random constraint satisfaction problems (zero energy groundstates of mean-field diluted spin glasses) undergoes several structural phase transitions as the amount of constraints is increased. This set first breaks down into a large number of well separated clusters. At the freezing transition, which is in general distinct from the clustering one, some variables (spins) take the same value in all solutions of a given cluster. In this paper we study the critical behavior around the freezing transition, which appears in the unfrozen phase as the divergence of the sizes of the rearrangements induced in response to the modification of a variable. The formalism is developed on generic constraint satisfaction problems and applied in particular to the random satisfiability of boolean formulas and to the coloring of random graphs. The computation is first performed in random tree ensembles, for which we underline a connection with percolation models and with the reconstruction problem of information theory. The validity of these results for the original random ensembles is then discussed in the framework of the cavity method.Comment: 32 pages, 7 figure