Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 36
Filtrar
1.
Phys Rev Lett ; 132(26): 261001, 2024 Jun 28.
Artigo em Inglês | MEDLINE | ID: mdl-38996294

RESUMO

Precision measurements by the Alpha Magnetic Spectrometer (AMS) on the International Space Station of the deuteron (D) flux are presented. The measurements are based on 21×10^{6} D nuclei in the rigidity range from 1.9 to 21 GV collected from May 2011 to April 2021. We observe that over the entire rigidity range the D flux exhibits nearly identical time variations with the p, ^{3}He, and ^{4}He fluxes. Above 4.5 GV, the D/^{4}He flux ratio is time independent and its rigidity dependence is well described by a single power law ∝R^{Δ} with Δ_{D/^{4}He}=-0.108±0.005. This is in contrast with the ^{3}He/^{4}He flux ratio for which we find Δ_{^{3}He/^{4}He}=-0.289±0.003. Above ∼13 GV we find a nearly identical rigidity dependence of the D and p fluxes with a D/p flux ratio of 0.027±0.001. These unexpected observations indicate that cosmic deuterons have a sizable primarylike component. With a method independent of cosmic ray propagation, we obtain the primary component of the D flux equal to 9.4±0.5% of the ^{4}He flux and the secondary component of the D flux equal to 58±5% of the ^{3}He flux.

2.
Phys Rev Lett ; 131(15): 151002, 2023 Oct 13.
Artigo em Inglês | MEDLINE | ID: mdl-37897756

RESUMO

We present the precision measurements of 11 years of daily cosmic positron fluxes in the rigidity range from 1.00 to 41.9 GV based on 3.4×10^{6} positrons collected with the Alpha Magnetic Spectrometer (AMS) aboard the International Space Station. The positron fluxes show distinctly different time variations from the electron fluxes at short and long timescales. A hysteresis between the electron fluxes and the positron fluxes is observed with a significance greater than 5σ at rigidities below 8.5 GV. On the contrary, the positron fluxes and the proton fluxes show similar time variation. Remarkably, we found that positron fluxes are modulated more than proton fluxes with a significance greater than 5σ for rigidities below 7 GV. These continuous daily positron fluxes, together with AMS daily electron, proton, and helium fluxes over an 11-year solar cycle, provide unique input to the understanding of both the charge-sign and mass dependencies of cosmic rays in the heliosphere.

3.
Phys Rev Lett ; 127(13): 131802, 2021 Sep 24.
Artigo em Inglês | MEDLINE | ID: mdl-34623867

RESUMO

Searches for the lepton number violating K^{+}→π^{-}µ^{+}e^{+} decay and the lepton flavor violating K^{+}→π^{+}µ^{-}e^{+} and π^{0}→µ^{-}e^{+} decays are reported using data collected by the NA62 experiment at CERN in 2017-2018. No evidence for these decays is found and upper limits of the branching ratios are obtained at 90% confidence level: B(K^{+}→π^{-}µ^{+}e^{+})<4.2×10^{-11}, B(K^{+}→π^{+}µ^{-}e^{+})<6.6×10^{-11} and B(π^{0}→µ^{-}e^{+})<3.2×10^{-10}. These results improve by 1 order of magnitude over previous results for these decay modes.

4.
Waste Manag ; 73: 523-534, 2018 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-28404511

RESUMO

The aim of the present study is to analyze the influence of independent process variables such as temperature, residence time, and heating rate on the torrefaction process of coffee chaff (CC) and spent coffee grounds (SCGs). Response surface methodology and a three-factor and three-level Box-Behnken design were used in order to evaluate the effects of the process variables on the weight loss (WL) and the Higher Heating Value (HHV) of the torrefied materials. Results showed that the effects of the three factors on both responses were sequenced as follows: temperature>residence time>heating rate. Data obtained from the experiments were analyzed by analysis of variance (ANOVA) and fitted to second-order polynomial models by using multiple regression analysis. Predictive models were determined, able to obtain satisfactory fittings of the experimental data, with coefficient of determination (R2) values higher than 0.95. An optimization study using Derringer's desired function methodology was also carried out and the optimal torrefaction conditions were found: temperature 271.7°C, residence time 20min, heating rate 5°C/min for CC and 256.0°C, 20min, 25°C/min for SCGs. The experimental values closely agree with the corresponding predicted values.


Assuntos
Café , Resíduos Industriais , Modelos Estatísticos , Gerenciamento de Resíduos , Calefação , Análise de Regressão , Temperatura
5.
Sci Total Environ ; 576: 129-137, 2017 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-27783931

RESUMO

Beef cattle production is a widespread activity in Italy in the agricultural field and determines an important impact on environment and resources consumption. Carbon footprint evaluation is thus necessary to evaluate the contributions of the different stages and the possible improvements of the production chain. In this study, two typical Italian beef production systems, a conventional and an organic one are investigated in order to evaluate the greenhouse gas emissions from "cradle to gate farm" by a Life Cycle Assessment (LCA) approach; the carbon footprint (CF) per 1kg of live weight meat is calculated. The contributions from feed production, enteric fermentation, and manure management are taken into account, in order to compare the life cycle of the two productions; also the carbon balance in soil is evaluated, in order to verify the impact in a life cycle perspective. The results of CF calculation of the two farms show that organic system (24.62kgCO2eq/kg live weight) produce more GHG emissions than the conventional one (18.21kgCO2eq/kg live weight) and that the enteric fermentation is the more heavy contribution, with a range of 50-54% of the global CF value. Improvements of the production chain could be realized by accurate feeding strategies, in order to obtain reduction of methane emissions from enteric digestion of cattles.

6.
Waste Manag ; 60: 151-157, 2017 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-27596944

RESUMO

The annual production of driftwood in Italy has been estimated to be more than 60,000 tonnes. This wood can be used as an energy source. Particular attention should be paid to its content of alkali and alkaline earth metals, sulfur and chlorine. Few works are available in the literature on this topic. For this reason, the authors propose experimental tests of combustion, gasification and pyrolysis, to evaluate the fate of alkali and alkaline earth metals, sulfur and chlorine in the solid residues and compare the three thermal degradation technologies. The results show a release of alkaline earth metals of about 45% of the initial quantity for gasification and a release of 55% of the initial quantity for combustion (while pyrolysis at 600°C has a very low release). The release of sodium is about 65% for gasification and 80% for combustion. It can be seen that the release of sodium is higher than that of alkaline earth metals; this is due to the divalency of the last ones. Dealing with the release of major elements (chlorine, sulfur and AAEMs) the tests have shown that pyrolysis process is a low emitting technology.


Assuntos
Poluentes Atmosféricos/análise , Incineração/métodos , Gerenciamento de Resíduos/métodos , Madeira/análise , Fontes Geradoras de Energia , Temperatura Alta , Itália , Resíduos Sólidos/análise , Madeira/química
7.
J Natl Cancer Inst ; 91(17): 1468-74, 1999 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-10469747

RESUMO

BACKGROUND: The incidence of Kaposi's sarcoma (KS) is increased severalfold in individuals infected with human immunodeficiency virus-1 (HIV). Human herpesvirus 8 (HHV8) has also been implicated in KS. We investigated several factors that may determine the onset of KS, particularly HHV8 infection in individuals after becoming seropositive for HIV. METHODS: We studied 366 individuals belonging to different HIV-exposure categories (i.e., homosexual activity, intravenous drug use, and heterosexual contact) for whom a negative HIV serologic test and then a positive HIV serologic test were available within a 2-year period. HHV8 antibody testing was performed by use of an immunofluorescence assay on the first serum sample available after the first positive HIV test. Actuarial rates of progression of KS and of other acquired immunodeficiency syndrome (AIDS)-defining diseases were estimated by use of time-to-event statistical methods. All statistical tests were two-sided. RESULTS: Twenty-one of the 366 study participants developed AIDS-related KS, and 83 developed AIDS without KS. One hundred forty (38.3%) participants had detectable anti-HHV8 antibodies. The actuarial progression rate to KS among persons co-infected with HIV/HHV8 was nearly 30% by 10 years after HIV seroconversion. Increasing HHV8 antibody titers increased the risk of developing KS (for seronegative versus highest titer [1:125 serum dilution], adjusted relative hazard [RH] = 51.82; 95% confidence interval [CI] = 6.08-441.33) but not of other AIDS-defining diseases (adjusted RH = 1.14; 95% CI = 0.72-1.80). HHV8-seropositive homosexual men compared with HHV8-seropositive participants from other HIV-exposure categories showed an increased risk of KS that approached statistical significance (adjusted RH = 6.93; 95% CI = 0.88-54.84). CONCLUSIONS: Approximately one third of individuals co-infected with HIV/HHV8 developed KS within 10 years after HIV seroconversion. Progression to KS increased with time after HIV seroconversion. Higher antibody titers to HHV8 appear to be related to faster progression to KS but not to other AIDS-defining diseases.


Assuntos
Infecções Oportunistas Relacionadas com a AIDS/virologia , Infecções por HIV/complicações , Infecções por Herpesviridae/complicações , Herpesvirus Humano 8/imunologia , Sarcoma de Kaposi/virologia , Análise Atuarial , Adolescente , Adulto , Idoso , Anticorpos Antivirais/sangue , Contagem de Linfócito CD4 , Progressão da Doença , Feminino , Herpesvirus Humano 4/imunologia , Humanos , Itália , Masculino , Pessoa de Meia-Idade , Risco
8.
Bioresour Technol ; 214: 266-275, 2016 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-27136614

RESUMO

The kinetic behaviour of olive tree pruning (PR), two- (2PH) and three-phase (3PH) olive pomace and their blends was investigated under combustion condition using thermogravimetric analysis. PR was blended with 2PH and 3PH at different ratios (25:75, 50:50 and 75:25) and tested in the temperature range from ambient to 1000°C in order to evaluate the co-combustion behaviour. Results showed that the thermal degradation of all samples can be divided into three regions (drying, devolatilisation, char oxidation) with different combustion properties, depending on the percentage of PR. Significant interaction was detected between the fuels, and reactivity of 2PH and 3PH was improved upon blending with PR. The iso-conversional methods, Ozawa-Flynn-Wall and Vyazovkin, were employed for the kinetic analysis of the oxidation process. The results revealed that the activation energy of PR was higher than the one of 2PH and 3PH, and the minimum value was obtained for 25PR752PH sample.


Assuntos
Resíduos Industriais , Azeite de Oliva , Eliminação de Resíduos/métodos , Indústria de Processamento de Alimentos , Temperatura Alta , Cinética , Olea/química , Azeite de Oliva/química , Termogravimetria
9.
Bioresour Technol ; 198: 470-7, 2015 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-26421610

RESUMO

Fermentable sugars production from three kind of steam-exploded oak wood was optimized by Response Surface Methodology (RSM), using the severity factor (R0), the pretreated total solids (TS%) and the enzyme loading (EL%) as variables of a central composite design. A total of 17 experiments for each biomass were carried out. The optimal conditions established with RSM were: severity, 4.46 for holm, 4.03 for turkey oak and 3.92 for downey oak; total solids, 5.4% for holm, 5.0% for turkey oak and 12.7% for downey oak; and enzyme concentration, 9.6% for holm, 15.0% for turkey oak and 15.0% for downey oak. Under these conditions, the model predicted an overall sugar yield of 67.1% for holm, 79.9% for turkey oak and 68.4% for downey oak. The results of the confirmation experiments under optimal conditions agreed well with model predictions. Oak wood species may be a good feedstock for the production of reducing sugars.


Assuntos
Biotecnologia/métodos , Carboidratos/biossíntese , Quercus/química , Madeira/química , Biocombustíveis , Biomassa , Celulases/química , Celulases/metabolismo , Etanol/química , Etanol/metabolismo , Glucose/metabolismo , Hidrólise , Quercus/metabolismo , Vapor , Madeira/metabolismo
10.
Bioresour Technol ; 186: 154-162, 2015 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-25817025

RESUMO

The influence of the addition of cellulosic ethanol residue (CER) on the combustion of Indonesian sub-bituminous coal was analyzed by non isothermal thermo-gravimetric analysis (TGA). The effect of blends ratio (5%, 10%, 15% and 20%), interaction mechanism, and heating rate (5°C/min, 10°C/min, 15°C/min, 20°C/min) on the combustion process was studied. The results show that the increase of the blending ratio allows to achieve the increase of the combustibility index from 7.49E-08 to 5.26E-07 at the blending ratio of 20%. Two types of non-isothermal kinetic analysis methods (Ozawa-Flynn-Wall and Vyazovkin) were also applied. Results indicate that the activation energy of the blends decreases with increasing the conversion rate. In particular, the blending ratio of 20% confirms to have the better combustion performance, with the average value of the activation energy equal to 41.10 kJ/mol obtained by Ozawa-Flynn-Wall model and 31.17 kJ/mol obtained by Vyazovkin model.


Assuntos
Carvão Mineral/análise , Etanol/química , Esgotos/análise , Esgotos/química , Resíduos/análise , Biomassa , Temperatura Alta , Incineração/métodos , Cinética , Termogravimetria/métodos
11.
AIDS ; 3(2): 87-90, 1989 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-2496724

RESUMO

A multicentre cohort study was carried out to estimate the incidence of AIDS and HIV-related conditions in newly infected intravenous drug users (IVDU). The enrollment criteria included the identification of the seroconversion time. Two hundred and five subjects entered the study, and were followed for a mean of 26 months. Twelve subjects developed clinical AIDS over a 4-year period. The actuarial incidence of AIDS estimated by Kaplan-Meier survival technique was 17.8% by 4 years since seroconversion. The risk of developing AIDS increased significantly after 24 months from seroconversion. Relatively small figures accounted for the lack of statistical association between the risk factors investigated and the disease status.


PIP: The natural course of HIV infection in 205 intravenous drug users (IVDU) presenting at 11 centers in Italy was followed since 1983. Criteria for entering the study were spontaneous attendance at the clinic from January 1983-April 1988; history of IVDU; dated negative HIV test and a positive test not over 18 months later. 13 of the 205 subjects developed AIDS by 30 April 1988, a total of 447.25 person-years, for an overall incidence of AIDS of 2.9% person-years. The clinical presentation was opportunistic infections in 7, wasting syndrome in 5, and encephalopathy in 1. No Kaposi's sarcoma was seen. The incidence of AIDS was 1.5% in the 1st year; 2.9% after 2 years; 9.9% after 3 years and 17.9% after 42-48 months. The risk of AIDS increased significantly 24 months after seroconversion. 11 others developed AIDS-related complex (ARC) in the 4-year period, an incidence of 3.4% person-years. The minor opportunistic infections seen were zona (4 cases), oral candidiasis (2), and hairy leukoplakia (1). 2 subjects had myelopathy. 87 others developed persistent generalized lymphadenopathy (PGL). 45.8% of the group remained asymptomatic. The subjects mean age was 26, and the sex ratio was 4:1 overall, but 12:1 among the AIDS group. The natural history of AIDS in this series closely resembled other reports on male homosexuals.


Assuntos
Síndrome da Imunodeficiência Adquirida/transmissão , Soropositividade para HIV/transmissão , Transtornos Relacionados ao Uso de Substâncias/complicações , Complexo Relacionado com a AIDS/etiologia , Adolescente , Adulto , Feminino , Humanos , Injeções Intravenosas , Masculino , Fatores de Risco , Fatores de Tempo
13.
Minerva Med ; 66(86): 4665-8, 1975 Dec 15.
Artigo em Italiano | MEDLINE | ID: mdl-1207946

RESUMO

Notes on the literature data concerning renal alterations observed in the course of virus diseases, and on the results of experiments designed to show the nephrotoxic action of viruses and their possible investigation of certain nephropathies, are followed by the presentation of a case of serious renal insufficiency in a young woman with virus hepatitis. The clinical data, the history and the results of blood chemistry and function tests showed this to be attributable to glomerulonephritis, probably caused by the same virus.


Assuntos
Glomerulonefrite/etiologia , Hepatite A/complicações , Doença Aguda , Adulto , Fosfatase Alcalina/sangue , Amilases/sangue , Feminino , Glomerulonefrite/enzimologia , Hepatite A/enzimologia , Humanos , Transaminases/sangue
14.
Minerva Chir ; 35(3): 167-70, 1980 Feb 15.
Artigo em Italiano | MEDLINE | ID: mdl-7374976

RESUMO

Haemorrhoid cryosurgery in 528 cases operated since the University of Genoa Colon and Rectum Diseases Centre opened is illustrated. It is shown that the complete success of this technique is dependent on careful preoperative assessment, adoption of a suitable method, and proper post-operative management. An analysis of these three parameters is followed by a description of the immediate and 1-yr follow-up results observed in the reported series. The soundness of the method is asserted. Stress is laid on the fact that cryosurgery offers a valid alternative to conventional surgical methods, provided its indications are strictly adhered to.


Assuntos
Criocirurgia , Hemorroidas/cirurgia , Criocirurgia/instrumentação , Criocirurgia/métodos , Seguimentos , Humanos , Complicações Pós-Operatórias , Prognóstico
15.
Minerva Chir ; 48(11): 613-5, 1993 Jun 15.
Artigo em Italiano | MEDLINE | ID: mdl-8414101

RESUMO

Pre-operative skin test response has been evaluated in 50 cases of colorectal carcinoma. Cellular defense's depression was correlated with tumoral staging (p = < 0.001). In B2 and C groups, a higher incidence of metastatic and local recurrences was registered in subjects with low response. These last are suitable for a randomized trial including immunotherapy.


Assuntos
Neoplasias Colorretais/imunologia , Feminino , Seguimentos , Humanos , Imunidade Celular , Masculino , Prognóstico
16.
Minerva Chir ; 50(6): 591-4, 1995 Jun.
Artigo em Italiano | MEDLINE | ID: mdl-7501218

RESUMO

After investigation of the international literature on this subject, the authors describe a case report of adhesive-stenotic and retractile peritonitis, very likely caused bt a foreign body reaction (surgical stitches, gloves, rice powder, etc.?). This case-report is interesting both to remember the existence of this pathology and to limit its iatrogenic development. In conclusion, it is advisable to wash surgical gloves with sterile solutions and to limit enlarged bowel resections mostly in young people.


Assuntos
Corpos Estranhos/complicações , Peritonite/etiologia , Adolescente , Feminino , Corpos Estranhos/cirurgia , Granuloma de Corpo Estranho/complicações , Humanos , Doença Iatrogênica , Peritonite/cirurgia , Complicações Pós-Operatórias , Grampeadores Cirúrgicos
17.
Recenti Prog Med ; 81(10): 663-5, 1990 Oct.
Artigo em Italiano | MEDLINE | ID: mdl-2291012

RESUMO

The Authors describe a case of multiple myeloma in a patient with HIV infection: this is an exceptional observation in young people and in HIV seropositive patients. The marked proliferation of lymphocyte B polyclones, typically found in the advanced stages of HIV infection, could be a determining factor in the appearance of a malignant clone, causing the onset of multiple myeloma.


Assuntos
Soropositividade para HIV/complicações , Mieloma Múltiplo/etiologia , Adulto , Ensaio de Imunoadsorção Enzimática , Soropositividade para HIV/diagnóstico , Humanos , Masculino , Mieloma Múltiplo/diagnóstico
18.
Recenti Prog Med ; 82(2): 69-71, 1991 Feb.
Artigo em Italiano | MEDLINE | ID: mdl-2034870

RESUMO

In order to evaluate the antibody response to anti-hepatitis B vaccine, 21 heroin addicted with HIV infection previously vaccinated, were studied. 18 patients were asymptomatic and 3 were at the LAS stage. An antibody response was estimated at 1 and 12 months after the end of the vaccination. The first control showed that 62% presented a protective anti-HBs (higher than 10 mU/ml); after one year 70% of responders had a persistent immunity. The antibody response showed no correlation with the value of immunologic tests; the vaccine showed neither a significant evidence of side-effects nor a negative influence on the HIV infection.


Assuntos
Síndrome da Imunodeficiência Adquirida/imunologia , HIV-1 , Hepatite B/prevenção & controle , Dependência de Heroína/imunologia , Vacinas contra Hepatite Viral/imunologia , Síndrome da Imunodeficiência Adquirida/complicações , Soropositividade para HIV/complicações , Soropositividade para HIV/imunologia , Anticorpos Anti-Hepatite B/sangue , Dependência de Heroína/complicações , Humanos , Fatores de Tempo
19.
Sci Total Environ ; 482-483: 71-9, 2014 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-24636888

RESUMO

The cradle to grave carbon footprint (CF) and energy footprint (EF) analysis of extra virgin olive oil (EVOO) produced in the Province of Perugia (Umbria, Italy) is assessed. In this study, olive orchard cultivation, EVOO extraction, bottling, packaging, storage at -18°C and distribution in the main importing countries were studied from a life cycle assessment perspective, with the main objective of identifying the processes with the largest environmental impacts. The selected functional unit was 1L of EVOO, packaged for distribution. Inventory data was gathered mainly through both direct communication using questionnaires and direct measurements. To determine the CF the ISO/TS 14067:2013 was followed while the EF was evaluated according to ISO standards 14040 and 14044. Results showed that the most impacting process is the distribution, mainly due to the choice of employing air transport. The main other hot spots identified were the olive orchard fertilization, EVOO freezing during its storage at the olive mill factory and the manufacture of glass bottles. Suggested improvement opportunities included shifts in the EVOO transportation policy, the introduction of lighter glass bottles in the bottling process, the use of cooling agent with lower global warming potential and the employment of biodiesel in the farming machineries.


Assuntos
Agricultura/estatística & dados numéricos , Pegada de Carbono/estatística & dados numéricos , Monitoramento Ambiental , Óleos de Plantas , Poluentes Atmosféricos/análise , Poluição do Ar/estatística & dados numéricos , Dióxido de Carbono/análise , Itália , Azeite de Oliva
20.
Artigo em Inglês | MEDLINE | ID: mdl-23406500

RESUMO

Mineral oil hydrocarbons present in printing inks and recycled paper migrate from paper-based food packaging to foods primarily through the gas phase. Migration from two commercial products packed in recycled paperboard, i.e. muesli and egg pasta, was monitored up to the end of their shelf life (1 year) to study the influence of time, storage conditions, food packaging structure and temperature. Mineral oil saturated and aromatic hydrocarbons (MOSH and MOAH, respectively), and diisopropyl naphthalenes (DIPN) were monitored using online HPLC-GC/FID. Storage conditions were: free standing, shelved, and packed in transport boxes of corrugated board, to represent domestic, supermarket and warehouse storage, respectively. Migration to food whose packs were kept in transport boxes was the highest, especially after prolonged storage, followed by shelved and free-standing packs. Tested temperatures were representative of refrigeration, room temperature, storage in summer months and accelerated migration testing. Migration was strongly influenced by temperature: for egg pasta directly packed in paperboard, around 30 mg kg⁻¹ of MOSH migrated in 8 months at 20°C, but in only 1 week at 40°C. Muesli was contained into an internal polyethylene bag, which firstly adsorbed hydrocarbons and later released them partly towards the food. Differently, the external polypropylene bag, containing pasta and recycled paper tray, strongly limited the migration towards the atmosphere and gave rise to the highest level of food contamination. Tests at increased temperatures not only accelerated migration, but also widened the migration of hydrocarbons to higher molecular masses, highlighting thus a difficult interpretation of data from accelerated simulation.


Assuntos
Contaminação de Alimentos/análise , Embalagem de Alimentos , Hidrocarbonetos/química , Óleo Mineral/química , Papel , Reciclagem , Cromatografia Gasosa , Cromatografia Líquida de Alta Pressão , Cinética , Temperatura
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA