320 research outputs found
A note on the birefringence angle estimation in CMB data analysis
Parity violating physics beyond the standard model of particle physics
induces a rotation of the linear polarization of photons. This effect, also
known as cosmological birefringence (CB), can be tested with the observations
of the cosmic microwave background (CMB) anisotropies which are linearly
polarized at the level of . In particular CB produces non-null CMB
cross correlations between temperature and B mode-polarization, and between E-
and B-mode polarization. Here we study the properties of the so called
D-estimators, often used to constrain such an effect. After deriving the
framework of both frequentist and Bayesian analysis, we discuss the interplay
between birefringence and weak-lensing, which, albeit parity conserving,
modifies pre-existing TB and EB cross correlation.Comment: 12 pages. Accepted for publication in JCA
Climate Resilience Pathways of Rural Households. Evidence from Ethiopia
This paper explores the resilience capacity of rural Ethiopian households after the drought shock
occurred in 2011. The work develops an original empirical framework able to capture the policy and
socio-economic determinants of householdsâ resilience capacity by making parametric statistical
assumption on the resilience distribution. To this end, the analysis employs a two-wave
representative panel dataset aligned with detailed weather records while controlling for a large set
of household- and community-level characteristics. The analysis shows that the majority of these
factors affects significantly resilience capacity only in the group of households affected by the
drought shock, suggesting that the observed effect relates to the adaptive capacity enabled by
these factors, rather than a simple welfare effect. Three policy indications emerge from the findings
of the empirical model. First, government support programmes, such as the PSNP, appear to
sustain householdsâ resilience by helping them to reach the level of pre-shock total consumption,
but have no impact on the food-consumption resilience. Secondly, the âselling out assets strategyâ
affects positively on householdsâ resilience, but only in terms of food consumption. Finally, the
presence of informal institutions, such as social networks providing financial support, sharply
increases householdsâ resilience by helping them to reach pre-shock levels of food and total
consumption. Policies incentivizing the formation of these networks, through the participation of
households to agricultural cooperative, agricultural associations, or community projects, may also
help farmers in recovering their wealth level after a weather shoc
Ricerche su Difilo di Sinope
Difilo di Sinope (IV/III sec. a.C.) è considerato, perlomeno a partire dal I sec. d.C., uno dei tre maggiori rappresentanti della commedia nuova, accanto a Menandro e Filemone. Il presente studio è articolato in due sezioni. La prima parte è dedicata a inquadrare Difilo nello spazio e nel tempo in cui operò sulla base di elementi sia esterni, forniti dalle testimonianze biografiche e aneddotiche, che interni, tramite lâanalisi di alcuni frammenti delle sue commedie, con lâobiettivo di mostrare che esse non sono da considerare avulse dal contesto storico in cui furono prodotte. La seconda parte, invece, indaga le modalitĂ della trasmissione e della ricezione dei suoi testi, tanto in Grecia, dalle revisioni dâautore alla fine della circolazione delle copie, anche attraverso lâesame delle scarne citazioni papiracee, quanto a Roma, con lo studio delle riprese da parte dei commediografi latini e delle testimonianze che collocano il poeta nel canone della commedia nuova
Design of a Rule Based System to Assign Components to Drive Maps
Questo lavoro di tesi sâinserisce allâinterno del macroprogetto Leanergie portato avanti dallâuniversitĂ di Hannover nel campo delle macchine utensili, con lo scopo di prevedere giĂ durante la fase di progettazione il consumo di energia della macchina a seconda dello scenario applicativo, in modo da poter pianificare la miglior combinazione dei diversi componenti in termini di consumo di energia. La previsione del consumo di energia, a differenza degli altri metodi basati su modelli matematici e simulativi, è basata su informazioni empiriche acquisite durante il funzionamento della macchina. Questo lavoro si è occupato in particolare di permettere una previsione del consumo di energia tutte le volte in cui non è possibile avere informazioni empiriche su un dato componente, ad esempio quando non è possibile estrarre dati operativi o quando sono presenti nuovi componenti che non hanno mai avuto un applicazione industriale. Per ottenere tali risultati, è stato sviluppato un concetto basato sulla Fuzzy Logic che assegni ad ogni componente privo di informazioni empiriche un diagramma che approssimi il suo funzionamento e il suo consumo di energia nella maniera piĂš precisa possibile
Fertilisation with compost mitigates salt stress in tomato by affecting plant metabolomics and nutritional profiles
Abstract
Background
Salinity is one of the major threats for crop growth and yield and its rate of expansion is expected to increase. We conducted a pot experiment to evaluate and compare the effect of a green compost addition and mineral fertilisation, on growth, nutrition and metabolites of tomato plants, exposed to increasing doses of NaCl.
Results
Although the development of stressed plants was lower than the corresponding controls, compost-treated plants performed better than mineral-amended plants watered with the same amount of salt. The different plant growth was related to an increased nutritional status. Namely, compost-treated plants showed a larger content of macro- and micronutrients, and a greater accumulation of osmoprotectants, such as soluble sugars and amino acids. Moreover, compost-treated plants showed a larger content of metabolites involved in modulating the response to salt stress, such as molecules related to energy transfer in plants and precursors of Reactive Oxygen Species scavenging compounds. Overall, the better performance of compost-added plants may be attributed to a greater availability of the organic forms of nutrients and to the positive bioactivity of compost-derived humic substances.
Conclusions
Compost application efficiently mitigated salt stress in tomato plants in respect to mineral fertilisation. This alleviating role was associated to the induction of a more efficient metabolic response that increased accumulation of metabolites involved in modulating the salinity stress. Therefore, fertilising with composted agricultural residue may represent a convenient alternative to mineral fertilisers to grow tomato plants in the presence of salt stress.
Graphical Abstrac
Continuum and atomistic description of excess electrons in TiO2
The modelling of an excess electron in a semiconductor in a prototypical dye sensitised solar cell is carried out using two complementary approaches: atomistic simulation of the TiO2 nanoparticle surface is complemented by a dielectric continuum model of the solventâsemiconductor interface. The two methods are employed to characterise the bound (excitonic) states formed by the interaction of the electron in the semiconductor with a positive charge opposite the interface. Density-functional theory (DFT) calculations show that the excess electron in TiO2 in the presence of a counterion is not fully localised but extends laterally over a large region, larger than system sizes accessible to DFT calculations. The numerical description of the excess electron at the semiconductorâelectrolyte interface based on the continuum model shows that the exciton is also delocalised over a large area: the exciton radius can have values from tens to hundreds of Ă
ngstrĂśms, depending on the nature of the semiconductor (characterised by the dielectric constant and the electron effective mass in our model)
Atypical presentation of anti-N-methyl-D-aspartate receptor encephalitis: Two case reports
Background: Anti-N-methyl-D-aspartate receptor encephalitis is a rare autoimmune disease characterized by severe neurological and psychiatric symptoms and a difficult diagnosis. The disease is often secondary to a neoplastic lesion, seldom diagnosed years later. Psychiatric symptoms are prevalent in adults; neurologic symptoms are more evident in children, who typically present primarily with neurological symptoms. To the best of our knowledge, the association with juvenile idiopathic arthritis has not been described. Case presentation: We report the cases of two caucasian girls with an atypical presentation. The first patient was an 8-year-old girl with normal psychomotor development. Over a 4-month period she developed behavioral problems, speech impairment, and deterioration in academic skills. Within 8 months from the onset of symptoms, choreic movements gradually appeared. Hematological, neuroradiological, and neurophysiological examinations were negative; however, her symptoms worsened and treatment with prednisone was started. Although her choreic movements improved within 1 month, her neuropsychological and behavioral symptoms continued. Anti-N-methyl-D-aspartate receptor antibodies in cerebrospinal fluid and in blood were detected. Therapy with intravenously administered immunoglobulins was administered, without improvement of symptoms. After 2 months of steroid treatment, she suddenly started to pronounce some words with a progressive improvement in language and behavior. The second patient was a 14-year-old girl with classic anti-N-methyl-D-aspartate receptor encephalitis, treated successfully with intravenously administered immunoglobulins and methylprednisolone, followed by orally administered prednisone, who developed chronic arthritis of the hip. The arthritis was confirmed by magnetic resonance imaging and associated to antinuclear antigen antibody positivity. One year after the encephalitis presentation, an ovarian cystic mass was identified as a teratoma. The surgical resection of the mass was followed by the resolution of the psychotic spectrum and arthritis. Conclusions: Anti-N-methyl-D-aspartate receptor encephalitis in pediatric patients can present initially with neuropsychological and behavioral symptoms. In the literature, the association of anti-N-methyl-D-aspartate receptor encephalitis with juvenile idiopathic arthritis is not yet described: to the best of our knowledge, this is the first case reported. The link to a neoplastic lesion can explain the favorable course of encephalitis and arthritis, after the surgical resection of the mass. Early diagnosis and treatment can improve the patient's outcome
Control-theoretical load-balancing for cloud applications with brownout
Cloud applications are often subject to unexpected events like flash crowds and hardware failures. Without a predictable behaviour, users may abandon an unresponsive application. This problem has been partially solved on two separate fronts: first, by adding a self-adaptive feature called brownout inside cloud applications to bound response times by modulating user experience, and, second, by introducing replicas -- copies of the applications having the same functionalities -- for redundancy and adding a load-balancer to direct incoming traffic. However, existing load-balancing strategies interfere with brownout self-adaptivity. Load-balancers are often based on response times, that are already controlled by the self-adaptive features of the application, hence they are not a good indicator of how well a replica is performing. In this paper, we present novel load-balancing strategies, specifically designed to support brownout applications. They base their decision not on response time, but on user experience degradation. We implemented our strategies in a self-adaptive application simulator, together with some state-of-the-art solutions. Results obtained in multiple scenarios show that the proposed strategies bring significant improvements when compared to the state-of-the-art ones
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