253 research outputs found

    Modeling the herd prey response to individualistic predators attacks

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    In this paper, we consider predators hunting on prey gathered in groups and in such way exhibiting the possibility of reducing the predators pressure. To model this feature, however, we depart from the Holling type II (HTII) response function, in that we assume that a sufficiently large set of prey could respond to individualistic attacks and therefore induce the predator to renounce. The basic idea is described at first in a simple two-populations predator-prey system. It is then expanded considering the generalist predators to deal with two prey. In the first case, both are gathered in herds, and in the second one, one of the two instead behaves individualistically. The net outcome is an enhanced survival for the prey with respect to both the herding cases without and with predators feeding satiation (i.e., using the HTII response)

    Quaternion methods for random matrices in quantum physics

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    The theory of random matrices, or random matrix theory, RMT in what follows, has been developed at the beginning of the fties to describe the sta- tistical properties of energy levels of complex quantum systems, [1], [2], [3]. In the early eighties it has enjoyed renewed interest since it has been recognized as a very useful tool in the study of numerous physical systems. Specically, it is very useful in the analysis of chaotic quantum systems. In fact, in the last years many papers appeared about the problem of quantum chaos which implies the quantization of systems whose underlying classical dynamics is irregular (i.e. chaotic). The simplest models considered in this eld are billi- ards of various shapes. From the the classical point of view, a point particle in a 2-dimensional billiard displays regular or irregular motion depending on the shape of the billiard; for instance motion in a rectangular or circular billi- ard is regular thanks to the symmetries of the boundary. On the other hand, billiards of arbitrary shapes imply chaotic motion, i.e. exponential diver- gence of initially nearby trajectories. In order to study quantum billiards we have to consider the Schroedinger equation in various 2-dimensional domains. The eigenvalues of the Schroedinger equation represent the allowed energy levels of our quantum particle in the billiard under consideration, while the eigenfunction norms represent the probability density of nding the particle in a certain position. The question of quantum chaos is whether the charac- ter of the classical motion (regular or chaotic) can in uence some propertie

    Surgical ‘damage control’ treatment of a large retroperitoneal liposarcoma encasing a horseshoe kidney

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    Damage control is a surgical strategy for severely compromised trauma patients based on speed control of life-threatening injuries that aims to rapidly resuscitate patients in an intensive care unit (ICU). We report on the use of such therapeutic strategy in a patient affected by a retroperitoneal sarcoma concomitant to a horseshoe kidney, a relatively rare anatomical malformation

    Glasgow Prognostic Score Class 2 Predicts Prolonged Intensive Care Unit Stay in Patients Undergoing Pneumonectomy

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    Background. The Glasgow prognostic score (GPS) is an inflammation-based score based on albuminemia and Creactive protein concentration proved to be associated with cancer-specific survival in several neoplasms. The present study explored the immediate postoperative value of the GPS for patients undergoing pneumonectomy for lung cancer. Methods. The value of the GPS preoperatively was studied in 250 patients undergoing pneumonectomy for non-small cell lung cancer (NSCLC). We analyzed overall postoperative complications, pulmonary and cardiac complications, 30-day postoperative death, reoperation for early complications, intensive care unit (ICU) length of stay and total length of hospital stay. Results. Patients with a GPS of 0 and 1 had a mean ICU length of stay of 0.8 days, whereas patients with a GPS of 2 had a mean ICU stay of 5.0 days (p = 0.004). The postoperative mortality rate in patients with a GPS of 2 was much higher than in patients with a GPS of 1 and 2, although it was not statistically significant (p = 0.083). Conclusions. A preoperative GPS of 2 effectively predicts a prolonged ICU stay in patients who undergo pneumonectomy for cancer. The score may be proposed as an easy-to-determine, economical, and fast preoperative tool to plan and optimize ICU admissions after elective pneumonectomy

    Migration paths saturations in meta-epidemic systems

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    In this paper we consider a simple two-patch model in which a population affected by a disease can freely move. We assume that the capacity of the interconnected paths is limited, and thereby influencing the migration rates. Possible habitat disruptions due to human activities or natural events are accounted for. The demographic assumptions prevent the ecosystem to be wiped out, and the disease remains endemic in both populated patches at a stable equilibrium, but possibly also with an oscillatory behavior in the case of unidirectional migrations. Interestingly, if infected cannot migrate, it is possible that one patch becomes disease-free. This fact could be exploited to keep disease-free at least part of the population

    Weekly paclitaxel as first-line chemotherapy in elderly advanced breast cancer patients: a phase II study of the Gruppo Italiano di Oncologia Geriatrica (GIOGer)

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    Background: First-line chemotherapy regimens suitable for elderly advanced breast cancer patients are still not defined. Patients and methods: Women with stage III or IV breast cancer aged >_70 years were enrolled in a phase II study aimed to evaluate both activity and toxicity of weekly paclitaxel. Among 46 planned patients, at least 18 responses and not more than seven unacceptable toxic events are required for a favourable conclusion. Paclitaxel 80 mg/m2 was administered weekly for 3 weeks every 28 days. Results: Unacceptable toxicity occurred in seven out of 46 patients evaluated for toxicity [15.2%; exact 95% confidence interval (CI) 7.6% to 28.2%] and was represented by one case of febrile neutropenia, one case of severe allergic reaction and five cases of cardiac toxicity. Among 41 patients evaluated for response, a complete response occurred in two (4.9%) patients and a partial response in 20 (48.8%), with an overall response rate of 53.7% (exact 95% CI 38.7% to 67.9%). The median progression-free survival was 9.7 months (95% CI 8.5\u201318.7) and median survival was 35.8 months (95% CI 19\u2013not defined). Conclusions: Weekly paclitaxel is highly active in elderly advanced breast cancer patients. Data on cardiovascular complications, however, indicate the need for a careful monitoring of cardiac function before and during chemotherap

    Novel correlations between spectroscopic and morphological properties of activated carbons from waste coffee grounds

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    Massive quantities of spent coffee grounds (SCGs) are generated by users around the world. Different processes have been proposed for SCG valorization, including pyrolytic processes to achieve carbonaceous materials. Here, we report the preparation of activated carbons through pyrolytic processes carried out under different experimental conditions and in the presence of various porosity activators. Textural and chemical characterization of the obtained carbons have been achieved through Brunauer–Emmett–Teller (BET), ESEM,13C solid state NMR, XPS, XRD, thermogravimetric and spectroscopic determinations. The aim of the paper is to relate these data to the preparation method, evaluating the correlation between the spectroscopic data and the physical and textural properties, also in comparison with the corresponding data obtained for three commercial activated carbons used in industrial adsorption processes. Some correlations have been observed between the Raman and XPS data

    Integrità elettorale e voto regionale

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    La sezione monografica ha un duplice intento. Da un lato, dar conto di alcuni degli sviluppi e delle problematiche di integrità elettorale associati alla dimensione propriamente procedurale delle consultazioni elettorali in Italia. In particolare sono stati considerati argomenti problematici che impattano sia sulla formazione dell’offerta politica (la trasparenza nella selezione e proposta delle coalizioni e delle candidature); la possibilità di un terzo mandato per i Presidenti di regione; l’uso della propaganda online nelle campagne elettorali regionali; l’espressione della partecipazione (l’opportunità di dotarsi di modalità di voto elettronico; l’incidenza del voto non valido nelle elezioni parlamentari in prospettiva comparata europea. Dall’altro lato si è inteso soffermare l’attenzione sul voto regionale, con riferimento ad alcuni degli aspetti procedurali appena richiamati, ma anche (secondo una prassi consolidata della Rivista) all’analisi delle elezioni regionali del febbraio 2023 – segnate da un forte tasso di astensionismo nonché da una netta affermazione della coalizione conservatrice che ha vinto le elezioni politiche del settembre 2022 – nelle due Regioni più popolose d’Italia: Lazio e Lombardia. L’insieme dei contributi si contraddistingue, oltre che per l’approfondimento dei temi con una particolare attenzione alla dimensione empirica, per la sua interdisciplinarietà che offre spazio a contributi di taglio non solo giuridico ma anche politologico
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