Nearly-optimal scheduling of users with Markovian time-varying transmission rates

We address the problem of developing a well-performing and implementable scheduler of users with wireless connections to the central controller, which arise in areas such as mobile data networks, heterogeneous networks, or vehicular communications systems. The main feature of such systems is that the connection quality of each user is time-varying, resulting in time-varying transmission rate corresponding to available channel states. We assume that this evolution is Markovian, relaxing the common but unrealistic assumption of stationary channels. We first focus on the three-state channel and study the optimal policy, showing that threshold policies (of giving higher priority to users with higher transmission rate) are not necessarily optimal. For the general channel we design a scheduler which generalizes the recently proposed Potential Improvement (PI) scheduler, and propose its two practical approximations, whose performance is analyzed and compared to existing alternative schedulers in a variety of simulation scenarios. We suggest and give evidence that the variant of PI which only relies on the steady-state distribution of the channel, performs extremely well, and therefore should be used for practical implementation

Markovian binary trees subject to catastrophes: computation of the extinction probability

This thesis is focused on the study of the probability that a certain Markovian binary tree becomes extinct. Diefferently from most of the existing literature, this study has been conducted through a matrix approach instead of probabilistic. A Markovian binary tree (MBT) is a model suitable for processes of evolution involving a population of individuals, wherein each of them evolves independently from the others. At every moment, the whole population can be partitioned into a finite number of typologies. During its life, an individual evolves and various events may happen, according to established probabilistic rules, in particular: - an individual can change its type and continue its life; - an individual can generate another individual and continue its life, the newborn individual will evolve independently from its parent; - an individual can die. An MBT is said to be extinct whenever there are no more individuals alive. In particular, in our analysis, we are interested in computing the probability that a certain tree will become extinct conditioned that the starting population consists of only one individual. This problem has been tackled with a renewed interest in the last years, since the vector of extinction probabilities was identied as the minimal nonnegative solution of a certain quadratic vector equation. Various algorithms have been proposed for computing such a solution, and a survey of them is reported in the thesis. In this work we deal with an extension of this model, in fact, beside the process of the population, we introduce a parallel independent process of catastrophes. When a catastrophe happens it influences every individual alive at the moment, who may die or survive with a probability depending on their current type. Also in this case we are interested in computing the extinction probability vector, however the challenge is much harder since the quadratic vector equation employed in the classical MBT case is not true anymore. In a recent work, Hautphenne et al. pointed out the importance of a parameter, whose positivity or negativity plays the discriminating role between the processes that will survive forever with a certain positive probability and those which will become extinct almost surely. The problem is that even only the computation of this parameter is beyond our possibilities. In fact, it is showed in the thesis how its computation of is equivalent to the computation of the maximal Lyapunov exponent of a random dynamical system, a problem that is well known to be hard apart from special cases. Hautphenne et al. proposed an upper and a lower bound for such a parameter by using probabilistic arguments. In this thesis, by using matrix properties, we provide different expressions for the value of the parameter and we derive some upper and lower bounds. We conclude the thesis by showing with numerical experiment when the various bounds are accurate or not. It becomes evident that the upper bound provided by Hautphenne et al. is still the best upper bound available, on the other hand the lower bound we suggested works better than the one available before

Gene Position More Strongly Influences Cell-Free Protein Expression from Operons than T7 Transcriptional Promoter Strength

The cell-free transcription-translation of multiple proteins typically exploits genes placed behind strong transcriptional promoters that reside on separate pieces of DNA so that protein levels can be easily controlled by changing DNA template concentration. However, such systems are not amenable to the construction of artificial cells with a synthetic genome. Herein, we evaluated the activity of a series of T7 transcriptional promoters by monitoring the fluorescence arising from a genetically encoded Spinach aptamer. Subsequently the influences of transcriptional promoter strength on fluorescent protein synthesis from one, two, and three gene operons were assessed. It was found that transcriptional promoter strength was more effective at controlling RNA synthesis than protein synthesis in vitro with the PURE system. Conversely, the gene position within the operon strongly influenced protein synthesis but not RNA synthesis

Morphological characteristics of “Bracco Italiano” dog

The Italian Bracco is one of the oldest pointing dog breed, used for hunting ever since the Renaissance time; paintings of the 14th century show hunting sceneries with dogs similar to the present day Bracco. The breed has been officially registered by ENCI (the Italian cynological club) in 1949, when the definitive standard was established. In this work, we report the first results of a study aimed at measuring morphological traits in this breed, as a part of a more comprehensive study whose objective is to identify the characters that have the potential of being genetically improved. Body measures were taken from 121 adult (mean age 4.09±2.64 years) Bracco Italiano dogs (65 males and 56 females). For each animal the following biometrical measurements were considered: withers height, chest height, length of the rump (RL), iliac width of rump, chest and cannon circumference. The ratio chest/cannon circumference was calculated, as index of body compactness. The proportion rump length-withers height (RLWH) was also calculated. ANOVA was used to test the differences between males and females for morphological measurements (sex as fixed factor and age at measurement as covariate). Data were analysed by JMP software version 5.0 of SAS Inst. Significant differences were observed between the means of females and males for withers height (59.0±2.95 cm in females and 62.1±2.73 cm in males; P<0.01), chest circumference (71.3±5.46 cm and 73.9±3.97 cm, in females and males respectively; P<0.01) and cannon circumference (12.6±0.98 cm and 13.6±0.90 cm in females and males respectively; P<0.05). The other measurements were not different between sexes. Sexual dimorphism was evident and generally the measures coincided with what reported in the standard, except for the length of the rump, which was around ¼ of the withers height instead of the value of 1/3 required in the standard

Genetic variability of the Bracco Italiano dog breed based on microsatellite polimorphism

The Bracco Italiano is one of the oldest breeds of Italian pointing dogs, used for hunting ever since Renaissance times. After the Second World War it was included among the breeds officially recorded by the ENCI (the Italian Cynological Club), and since 1970 more than 23,000 animals have been registered; there are currently approximately 750 births per year. In this paper, we present the breed characterization of the population at the molecular level using 21 STR markers from the panels recommended for the 2006, 2008 and 2010 ISAG canine comparison test. Number of alleles, allele frequencies, deviations from Hardy-Weinberg proportions, linkage disequilibrium among loci, genetic similarity, genetic distances and molecular co-ancestry-based parameters were calculated. The number of alleles ranged from 3 to 9 (mean 6.43) whereas the expected heterozygosity ranged from 0.44 to 0.81 (mean 0.64). There was a high genetic similarity within the whole population (0.455) showing the great homogeneity of the sampled animals, as confirmed also by the small kinship distance (0.336), by the high values of the self molecular coancestry (0.703) and of the inbreeding coefficient (0.406). These results suggest the need for a careful genetic management of the population in order to avoid the risk of an excessive increase in the inbreeding level which would result in significant inbreeding depression and in significant loss of genetic variation

Relative influence of noncovalent interactions on the melting points of a homologous series of 1,2-dibromo- 4,5-dialkoxybenzenes

Crystal structures are presented for two members of the homologous series of 1,2-dibromo-4,5-dialkoxybenzenes, viz. those with decyloxy and hexadecyloxy substituents, namely 1,2-dibromo-4,5-bis(decyloxy)benzene, C26H44Br2O2, (II), and 1,2-dibromo-4,5-bis(hexadecyloxy)benzene, C38H68Br2O2, (III). The relative influences which halogen bonding, π- π stacking and van der Waals interactions have on these structures are analysed and the results compared with those already found for the lightest homologue, 1,2-dibromo-4,5- dimethoxybenzene, (I) [Cukiernik, Zelcer, Garland & Baggio (2008). Acta Cryst. C64, o604-o608]. The results confirm that the prevalent interactions stabilizing the structures of (II) and (III) are van der Waals contacts between the aliphatic chains. In the case of (II), weak halogen C - Br ⋯(Br - C) ′ interactions are also present and contribute to the stability of the structure. In the case of (III), van der Waals interactions between the aliphatic chains are almost exclusive, weaker C - Br ⋯ π interactions being the only additional interactions detected. The results are in line with commonly accepted models concerning trends in crystal stability along a homologous series (as measured by their melting points), but the earlier report for n = 1, and the present report for n = 10 and 16, are among the few providing single-crystal information validating the hypothesis.Fil: Fonrouge, Ana. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química, Física de los Materiales, Medioambiente y Energía. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química, Física de los Materiales, Medioambiente y Energía; ArgentinaFil: Cecchi, Florencia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química, Física de los Materiales, Medioambiente y Energía. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química, Física de los Materiales, Medioambiente y Energía; ArgentinaFil: Alborés, Pablo. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química, Física de los Materiales, Medioambiente y Energía. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química, Física de los Materiales, Medioambiente y Energía; ArgentinaFil: Baggio, Ricardo Fortunato. Comisión Nacional de Energía Atómica; ArgentinaFil: Cukiernik, Fabio Daniel. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química, Física de los Materiales, Medioambiente y Energía. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química, Física de los Materiales, Medioambiente y Energía; Argentin

Composition and acaricidal activity of Laurus novocanariensis and Laurus nobilis essential oils against Psoroptes cuniculi

The major components of Laurus nobilis and L. novocanariensis leaf oils were identifi ed and their acaricidal activity against Psoroptes cuniculi evaluated. Monoterpenes were predominant in L. nobilis oil (91.8%), while ses quiterpenes were only 1.4%. The main components of this oil were 1,8-cineole (39.2%), α-terpinyl acetate (11.3%), sabinene (10.6%) and linalool (7.4%). The acaricidal activity of L. nobilis oil, at a concentration of 10%, led to a mortality rate of 73%; at 5% the average activity was signifi cantly reduced to 51%, while dilutions of 2.5%, 1.25% and 0.625% were ineffective. Laurus novocanariensis oil, compared to L. nobilis, was richer in sesquiterpenes; the main constituents were α-pinene (10.4%), 1,8-cineole (9.6%) and β-selinene (7.2%). After 24 h of contact, the oil of L. novocanariensis killed all the mites when used at 10% and 5% concentrations. At lower concentrations the mortality signifi cantly decreased; a dilution of 0.625% was ineffective.info:eu-repo/semantics/publishedVersio

The effects of an invasive seaweed on native communities vary along a gradient of land-based human impacts

The difficulty in teasing apart the effects of biological invasions from those of other anthropogenic perturbations has hampered our understanding of the mechanisms underpinning the global biodiversity crisis. The recent elaboration of global-scale maps of cumulative human impacts provides a unique opportunity to assess how the impact of invaders varies among areas exposed to different anthropogenic activities. A recent meta-analysis has shown that the effects of invasive seaweeds on native biota tend to be more negative in relatively pristine than in human-impacted environments. Here, we tested this hypothesis through the experimental removal of the invasive green seaweed, Caulerpa cylindracea, from rocky reefs across the Mediterranean Sea. More specifically, we assessed which out of land-based and sea-based cumulative impact scores was a better predictor of the direction and magnitude of the effects of this seaweed on extant and recovering native assemblages. Approximately 15 months after the start of the experiment, the removal of C. cylindracea from extant assemblages enhanced the cover of canopy-forming macroalgae at relatively pristine sites. This did not, however, result in major changes in total cover or species richness of native assemblages. Preventing C. cylindracea re-invasion of cleared plots at pristine sites promoted the recovery of canopyforming and encrusting macroalgae and hampered that of algal turfs, ultimately resulting in increased species richness. These effects weakened progressively with increasing levels of land-based human impacts and, indeed, shifted in sign at the upper end of the gradient investigated. Thus, at sites exposed to intense disturbance from land-based human activities, the removal of C. cylindracea fostered the cover of algal turfs and decreased that of encrusting algae, with no net effect on species richness. Our results suggests that competition from C. cylindracea is an important determinant of benthic assemblage diversity in pristine environments, but less so in species-poor assemblages found at sites exposed to intense disturbance from landbased human activities, where either adverse physical factors or lack of propagules may constrain the number of potential native colonizers. Implementing measures to reduce the establishment and spread of C. cylindracea in areas little impacted by land-based human activities should be considered a priority for preserving the biodiversity of Mediterranean shallow rocky reefs

Intestinal helminths of the endemic Italian hare, Lepus corsicanus (De Winton, 1898), in Sicily (Italy)

The Italian hare (Lepus corsicanus De Winton, 1898) is endemic to central and southern Italy, where it lives in sympatry with Lepus europaeus in the mainland, while in Sicily L. europaeus is absent. The only report of endoparasites in L. corsicanus in Italy dates back to 2012. After a period of protection, the population density of the Italian hare in Sicily increased. This enabled new parasitological data to be collected on 27 hares which were compared with the data collected on 15 Sicilian hares from a previous study. Trichostrongylus retortaeformis, Paranoplocephala sp. and Cittotaenia (Mosgovoyia) sp. were isolated from the intestine. T. retortaeformis was the most prevalent and abundant parasite. Its abundance was significantly higher in males than in females. No age differences emerged. T. retortaeformis abundance was not related to low body mass and was significantly higher than that calculated from the data of the previous survey. At the same time aggregation, known as a regulatory factor of host-parasite relationship, was also higher in the present study. The possible biases introduced by sampling with different methods prevent any definitive conclusions. However, the relationship between L. corsicanus and its intestinal parasite biocoenosis appears to be stable and has possibly improved, in line with the improved status of the host population