From Farkas’ lemma to linear programming: An exercise in diagrammatic algebra

Farkas’ lemma is a celebrated result on the solutions of systems of linear inequalities, which finds application pervasively in mathematics and computer science. In this work we show how to formulate and prove Farkas’ lemma in diagrammatic polyhedral algebra, a sound and complete graphical calculus for polyhedra. Furthermore, we show how linear programs can be modeled within the calculus and how some famous duality results can be proved

Oral health knowledge in pre-school children: a survey among parents in central Italy

Background: The aim of this survey was to evaluate the knowledge and awareness of parents about potential oral health risk factors and correct management of oral hygiene of their preschool children. Material and Methods: The participation to the survey was proposed to all parents of 3-5 year aged children attending a kindergarten in Campobasso. A self-administered questionnaire was completed to obtain information regarding demographic and education variables, knowledge about caries and its transmission, infant feeding practice, maternal oral health during pregnancy, parents and children’s oral hygiene habits and risk behaviors (e.g., sharing cutlery, tasting of baby food, nightly using of baby bottles or pacifier), oral health prevention and role of school. Results: Overall, the parents of 101 children consented to fill the questionnaire. Data analysis showed that only 24% of respondents was aware of the potential vertical transmissibility of cariogenic bacteria through contaminated saliva. It is still a common trend from61% of parents tasting food of their child. On 101 children, 30% used pacifier and 17% used baby bottle with milk during night and among these children 41% for more than 2 years. Parents reported no toothbrushing for 57% of the children in their first 3 years of life. Conclusions: From this survey, independently on parents education, it emerges as still nowadays parents are not fully trained and informed about the management of their child’s oral hygiene and as it’s necessary a parental oral health promoting program to control children oral health risk status, starting from school

Reconfiguration of optical-NFV network architectures based on cloud resource allocation and QoS degradation cost-aware prediction techniques

The high time required for the deployment of cloud resources in Network Function Virtualization network architectures has led to the proposal and investigation of algorithms for predicting trafc or the necessary processing and memory resources. However, it is well known that whatever approach is taken, a prediction error is inevitable. Two types of prediction errors can occur that have a different impact on the increase in network operational costs. In case the predicted values are higher than the real ones, the resource allocation algorithms will allocate more resources than necessary with the consequent introduction of an over-provisioning cost. Conversely, when the predicted values are lower than the real values, the allocation of fewer resources will lead to a degradation of QoS and the introduction of an under-provisioning cost. When over-provisioning and under-provisioning costs are different, most of the prediction algorithms proposed in the literature are not adequate because they are based on minimizing the mean square error or symmetric cost functions. For this reason we propose and investigate a forecasting methodology in which it is introduced an asymmetric cost function capable of weighing the costs of over-provisioning and under-provisioning differently. We have applied the proposed forecasting methodology for resource allocation in a Network Function Virtualization architectures where the Network Function Virtualization Infrastructure Point-of-Presences are interconnected by an elastic optical network.We have veried a cost savings of 40% compared to solutions that provide a minimization of the mean square error

The academic impact of natural disasters: evidence from L’Aquila earthquake

This paper uses a standard difference-in-differences approach to examine the effect of the L’Aquila earthquake on the academic performance of the students of the local university. The empirical results indicate that this natural disaster reduced students’ probability of graduating on-time and slightly increased students’ probability of dropping out. While post-disaster measures (e.g. fast re-establishment of education activities in temporary locations) are likely to have mitigated the effects of this event, disruptions in the learning environment and the mental trauma suffered by students in the aftermath of the earthquake may have worsened their academic performance

Controlled optimal black start procedures in smart grids for service restoration in presence of electrical storage systems

This paper presents an optimisation problem to determine the optimal reclosure order of remotely operable switches deployed in a smart grid consisting in a distribution network equipped with one or more Energy Storage Systems (ESS). The proposed solution integrates nonlinear real and reactive power flow equations, by reconducting them to a set of conic constraints, together with several network operator requirements, such as network radiality and ampacity limits. A numerical simulation validates the approach and concludes the work

What is a Gene? A Two Sided View

The need to account for all currently available experimental observations concerning the gene nature, has reshaped the concept of gene turning it from the essentially mechanistic unit, predominant during the '70s, into a quite abstract open and generalized entity, whose contour appears less defined as compared to the past. Here we propose the essence of the gene to be considered double faced. In this respect genotypic and phenotypic entities of a gene would coexist and mix reciprocally. This harmonizes present knowledge with current definitions and predisposes for remodelling of our thinking as a consequence of future discoveries. A two sided view of the gene also allows to combine the genetic and epigenetic aspects in a unique solution, being structural and functional at the same time and simultaneously able to include the different levels in an overlapping unicum

Environmental microbial contamination in dental setting: a local experience

ntroduction. Patients and operators are exposed during dental practice to an infective risk, which derives especially from micro- organisms suspended in aerosols. Environmental microbiologi- cal monitoring in dental settings represents a good instrument to detect critical situations. Methods. In order to investigate environmental microbial contami- nation level in a local reality, we analyzed water, air and surfaces samples of a community-based dental facility by using protocol and threshold values proposed in a recent multicenter study carried out by the Italian Society of Hygiene, Preventive Medicine and Public Health (S.It.I.) working group ?Hygiene in Dentistry?. Microbial contamination was assessed in the same room for 4 non-consecu- tive weeks during all the five working days, before and at the end of the daily activity. Air was sampled also during clinical activity, through both active and passive sampling systems. Results. Contamination of water showed a decrease during activ- ities, while a decrease in air contamination was registered only at the end of the day. Passive sampling values resulted more often above threshold values adopted. At the same time, surfaces con- tamination increases at the end of the activity. It seems that in the dental clinic analyzed microbial buildup represents the higher critical element. No differences have been registered among the different days of the week. Discussion. Our study highlights the need to improve disinfection procedures and air treatment systems in the considered environ- ment. Microbiological monitoring could represent an important element to detect the presence of risk factors and to adopt control measures

The intrinsic topological information of the wild-type and of up-promoter mutations of the Saccharomyces cerevisiae alcohol dehydrogenase II regulatory region.

A 569-base pair fragment encompassing the upstream regulatory region, the RNA initiation sites, and the initial part of the coding region of the Saccharomyces cerevisiae alcohol dehydrogenase II gene has been analyzed for the presence of sites which undergo conformational modification under torsional stress. Fine mapping of P1 and S1 endonuclease-sensitive sites was obtained on single topoisomers produced by in vitro ligation. It was shown that the upstream activator sequence, the TATA sequence, a region directly upstream to the RNA initiation sites, and several positions in the first segment of the transcribed region change conformation as a function of the applied torsional stress in a precisely coordinate fashion. The superhelical density optima for this coordinate modifications have been determined. Analysis of the conformational changes of the promoter sequence in several naturally occurring (Young, E. T., Williamson, V. M., Taguchi, A., Smith, M., Sledziewski, L., Russel, D., Osterman, J., Denis, C., Cox, D., and Beier, D., (1982) in Genetic Engineering of Microorganisms for Chemicals (Hollander, A., De Moss, R. D., Kaplan, S., Konisky, J., Savage, D., and Wolle, R. S., eds) pp. 335-361, Plenum Publishing Corp., New York) up-promoter constitutive mutants was performed. This analysis has shown that the conformation of functionally relevant sites changes as a function of sequence mutations that have taken place elsewhere; this shows that the conformational behavior of the whole promoter region is linked and suggests transmission in cis of topological effects in RNA polymerase II promoters

Different pulp dressing materials for the pulpotomy of primary teeth: A systematic review of the literature

Background: Pulpotomy of primary teeth provides favorable clinical results over time; however, to date, there is still not a consensus on an ideal pulp dressing material. Therefore, the aim of the present systematic review was to compare pulpotomy agents to establish a preferred material to use. Methods: After raising a PICO question, the PRISMA guideline was adopted to carry out an electronic search through the MEDLINE database to identify comparative studies on several pulp dressing agents, published up to October 2019. Results: The search resulted in 4274 records; after exclusion, a total of 41 papers were included in the present review. Mineral trioxide aggregate (MTA), Biodentine and ferric sulphate yielded good clinical results over time and might be safely used in the pulpotomies of primary molars. Among agents, MTA seemed to be the material of choice. On the contrary, calcium hydroxide showed the worst clinical performance. Although clinically successful, formocreosol should be replaced by other materials, due to its potential cytotoxicity and carcinogenicity. Conclusion: MTA seemed to be the gold standard material in the pulpotomy of primary teeth. Promising results were also provided by calcium silicate-based cements. Further randomized clinical trials (RCTs) with adequate sample sizes and long follow-ups are encouraged to support these outcomes