Mathematical Model of Easter Island Society Collapse

In this paper we consider a mathematical model for the evolution and collapse of the Easter Island society, starting from the fifth century until the last period of the society collapse (fifteen century). Based on historical reports, the available primary sources consisted almost exclusively on the trees. We describe the inhabitants and the resources as an isolated system and both considered as dynamic variables. A mathematical analysis about why the structure of the Easter Island community collapse is performed. In particular, we analyze the critical values of the fundamental parameters driving the interaction humans-environment and consequently leading to the collapse. The technological parameter, quantifying the exploitation of the resources, is calculated and applied to the case of other extinguished civilization (Cop\'an Maya) confirming, with a sufficiently precise estimation, the consistency of the adopted model.Comment: 9 pages, 1 figure, final version published on EuroPhysics Letter

Strange kinetics: conflict between density and trajectory description

We study a process of anomalous diffusion, based on intermittent velocity fluctuations, and we show that its scaling depends on whether we observe the motion of many independent trajectories or that of a Liouville-like equation driven density. The reason for this discrepancy seems to be that the Liouville-like equation is unable to reproduce the multi-scaling properties emerging from trajectory dynamics. We argue that this conflict between density and trajectory might help us to define the uncertain border between dynamics and thermodynamics, and that between quantum and classical physics as well.Comment: submitted to Chemical Physic

Integrating Dynamics and Wear Modelling to Predict Railway Wheel Profile Evolution

The aim of the work described was to predict wheel profile evolution by integrating multi-body dynamics simulations of a wheelset with a wear model. The wear modelling approach is based on a wear index commonly used in rail wear predictions. This assumes wear is proportional to Tγ, where T is tractive force and γ is slip at the wheel/rail interface. Twin disc testing of rail and wheel materials was carried out to generate wear coefficients for use in the model. The modelling code is interfaced with ADAMS/Rail, which produces multi-body dynamics simulations of a railway wheelset and contact conditions at the wheel/rail interface. Simplified theory of rolling contact is used to discretise the contact patches produced by ADAMS/Rail and calculate traction and slip within each. The wear model combines the simplified theory of rolling contact, ADAMS/Rail output and the wear coefficients to predict the wear and hence the change of wheel profile for given track layouts

Primary cosmic ray spectrum in the 10 to the 12th power - 10 to the 16th power eV energy range from the NUSEX experiment

A primary cosmic ray spectrum was derived which fits both experimental multiple muon rates and the all-nucleon flux derived from the single muon intensities underground. In the frame of the interaction model developed by Gaisser, Elbert and Stanev, it is possible to reproduce NUSEX muon data with a primary composition in which the iron spectrum is only slightly flatter than the proton one. This result rules out the popular idea that the primary composition varies drastically with increasing energy, leading to the dominance of heavier nuclei at energies 10 to the 15th power to 10 to the 16th power eV

Correlation of Bony Invasion With Nodal Metastasis, Pattern of Invasion and Survival in Oral Squamous Cell Carcinoma: A Retrospective Analysis of 122 Primary Cases From Oral Cancer Centre of South India

Oral squamous cell carcinoma (OSCC) is considered to be the most common epithelial malignant neoplasm of the oral cavity. Despite advancements in diagnosis and therapeutics the clinical outcome of the disease has not improved much which may be attributed to tumor biology and heterogeneity. Bone invasion by cancer cells is currently staged as a moderately advanced disease. However, many low-grade carcinomas such as verrucous carcinoma and carcinoma cuniculatum show body invasion but less nodal metastases and better overall survival. The present study was orchestrated to analyze if bone invasion in OSCC has any impact on regional nodal metastases and survival

Definition and description of larval types of Cyaneolytta (Coleoptera Meloidae) and new records of their phoretic association with Carabidae (Coleoptera)

The hypothesis of a general phoretic association of Cyaneolytta Péringuey 1909 triungulins (Meloidae) with Anthiini (Carabidae) is supported by many new records from several regions of Africa and India. Four morphological larval types of Cyaneolytta are described and some morpho-species belonging to different morphotypes are identified and illustrated

Results of low energy background measurements with the Liquid Scintillation Detector (LSD) of the Mont Blanc Laboratory

The 90 tons liquid scintillation detector (LSD) is fully running since October 1984, at a depth of 5,200 hg/sq cm of standard rock underground. The main goal is to search for neutrino bursts from collapsing stars. The experiment is very sensitive to detect low energy particles and has a very good signature to gamma-rays from (n,p) reaction which follows the upsilon e + p yields n + e sup + neutrino capture. The analysis of data is presented and the preliminary results on low energy measurements are discussed

Rosetta Philae SD2 Drill System and Its Operation on 67p/Churyumov-Gerasimenko

Rosetta Lander Philae approached and landed on the surface of comet 67P/Churyumov-Gerasimenko on the 12th of November 2014. Among the specific Subsystems and instruments carried on board, the Drill, Sample and Distribution System (SD2) which was in charge to drill the surface of the comet, take comet’s soil sample(s) and distribute the collected sample to different instruments. Rosetta has been launched in 2004 and, after very complex orbital trajectories and specific commissioning events, met and carried out a rendezvous with the comet; after ten years cruise and three subsequent touch down, Philae eventually landed on the comet surface. On the 14th of November 2014 SD2 was decided to be operated on the comet. This paper provides an overview of the achievements during the operational phase on the comet and will summarize the basic characteristics and peculiarities of SD2 drill system

Tau oligomers accumulation sensitizes prostate cancer cells to docetaxel treatment

Purpose: Human tau is a highly dynamic, multifunctional protein expressed in different isoforms and conformers, known to modulate microtubule turnover. Tau oligomers are considered pathologic forms of the protein able to initiate specific protein accumulation diseases, called tauopathies. In our study, we investigated the potential association between autophagy and tau oligomers accumulation and its role in the response of prostate cancer cells to docetaxel. Methods: We evaluated in vitro the expression of tau oligomers in prostate cancer cell lines, PC3 and DU145, in presence of autophagy inhibitors and investigated the role of tau oligomers accumulation in resistance to docetaxel treatment. Results: Tau protein was basally expressed in prostate cancer lines as several monomeric and oligomeric forms. The pharmacologic inhibition of autophagy induced in cancer cells the accumulation of tau protein, with a prevalent expression of oligomeric forms. Immunofluorescence analysis of untreated cells revealed that tau was visible mainly in dividing cells where it was localized on the mitotic spindle. Inhibition of autophagy determined an evident upregulation of tau signal in dividing cells and the presence of aberrant monoastral mitotic spindles. The accumulation of tau oligomers was associated with DNA DSB and increased cytotoxic effect by docetaxel. Conclusions: Our data indicate that autophagy could exert a promoting role in cancer growth and during chemotherapy facilitating degradation of tau protein and thus blocking the antimitotic effect of accumulated tau oligomers. Thus, therapeutic strategies aimed at stimulating tau oligomers formation, such as autophagy inhibition, could be an effective adjuvant in cancer therapy