836 research outputs found
Multi-year total ozone column variability at three Norwegian sites and the influence of Northern Hemisphere Climatic indices
Total ozone column (TOC) measurements are retrieved from the Ozone Monitoring Instrument (OMI) onboard the NASA Earth Observing System (EOS) Aura satellite at the three Norwegian sites: Oslo (59.9 degrees N 10.7 degrees E, 1 m a.s. l.), Trondheim (63.4 degrees N 10.4 degrees E, 3 m a.s.l.) and Andoya (69.1 degrees N 15.7 degrees E, 32 m a.s.l.). TOC data have been analysed from 2005 to 2021, in order to detect annual and multi-years total ozone variability. The relationship between geopotential height (GPH) at 250 hPa and total ozone column has been evaluated after showing that monthly anomalies in GPH and TOC are correlated amongst the three sites. The influence of the three Northern Hemisphere Tele Connection (TC) indices (North Atlantic Oscillation, Arctic Oscillation and Scandinavia) on TOC variability has been investigated. It is found that Scandinavia index plays a prominent role for the northernmost latitudes of Andoya and Trondheim while North Atlantic Oscillation and Arctic Oscillation indices are weakly correlated (negatively) to TOC and (positively) to GPH at Oslo. The response of TOC variability to the solar activity at the three sites is also explored and it is noticed that in the period of increasing variation of solar activity, significant TOC anomaly events are only observed in Andoya and Trondheim
Ground-based NO2 measurements at the Italian Brewer stations: A pilot study with Global Ozone Monitoring Experiment (GOME)
Ground-based NO2 total column measurements have been collected since 1992 using Brewer spectrophotometry at Rome, an urban site, and Ispra (semirural). These are the only ground-based stations regularly monitoring NO2 in Italy. The methodology of measurement together with the procedure to control its quality is described. From the analysis of the time series it was found that the mean value
of the NO2 column is 1.63 DU atRome and 1.60 DU atIspra. A firstat tempt to compare NO2 vertical column densities (VCD) from GOME with those derived from ground-based Brewer measurements, under different atmospheric conditions and measurement time lags is here presented. The results of this pilot study showed unsatisfactory agreement because different atmospheres are probed by GOME and Brewer instruments. The GOME space resolution resulted insufficient to fully characterize the Rome and Ispra highly localized polluted areas
Ground-based NO2 measurements at the Italian Brewer stations: A pilot study with Global Ozone Monitoring Experiment (GOME)
Ground-based NO2 total column measurements have been collected since 1992 using Brewer spectrophotometry at Rome, an urban site, and Ispra (semirural). These are the only ground-based stations regularly monitoring NO2 in Italy. The methodology of measurement together with the procedure to control its quality is described. From the analysis of the time series it was found that the mean value
of the NO2 column is 1.63 DU atRome and 1.60 DU atIspra. A firstat tempt to compare NO2 vertical column densities (VCD) from GOME with those derived from ground-based Brewer measurements, under different atmospheric conditions and measurement time lags is here presented. The results of this pilot study showed unsatisfactory agreement because different atmospheres are probed by GOME and Brewer instruments. The GOME space resolution resulted insufficient to fully characterize the Rome and Ispra highly localized polluted areas
Aerosol Single Scattering Albedo retrieval in the UV range: an application to OMI satellite validation
Abstract. The aerosol Single Scattering Albedo (SSA) and Absorbing Aerosol Optical Depth (AAOD) at 320.1 nm are derived at Rome site by the comparison between Brewer and modelled spectra. The UVSPEC radiative transfer model is used to calculate the UV irradiances for different SSA values, taking into account as input data total ozone and Aerosol Optical Depth (AOD) obtained from Brewer spectral measurements. The accuracy in determining SSA depends on the aerosol amount and on Solar Zenith Angle (SZA) value: SSA uncertainty increases when AOD and SZA decrease. The monthly mean values of SSA and AAOD during the period January 2005–June 2008 are analysed, showing a monthly and seasonal variability. It is found that the SSA and AAOD averages are 0.80±0.08 and 0.056±0.028, respectively. AAOD retrievals are also used to quantify the error in the Ozone Monitoring Instrument (OMI) surface UV products due to absorbing aerosols, not included in the current OMI UV algorithm. OMI and Brewer UV irradiances at 324.1 nm and Erythemal Dose Rates (EDRs) under clear sky conditions, are compared as a function of AAOD. Three methods are considered to investigate on the applicability of an absorbing aerosol correction on OMI UV data at Rome site. Depending on the correction methodology, the bias value decreases from 18% to 2% for spectral irradiance at 324.1 nm and from 25% to 8% for EDR
Personal UV exposure on a ski-field at an alpine site
International audienceMountain sites experience enhanced ambient UV radiation levels due to the concurrent effects of shorter radiation path-length, low aerosol load and high reflectivity of the snow surfaces. This study was encouraged by the possibility to collect data of personal UV exposure in the mountainous areas of Italy, for the first time. Personal UV exposure (expressed in terms of Exposure Ratio, ER) of two groups of volunteers (ski instructors and skiers) at the Alpine site of La Thuile (Valle d'Aosta region, Italy) was assessed using polysulphone dosimetry which was tested in a mountainous snow-covered environment. In addition measurements of biological markers of individual response to UV exposure such as skin colorimetric parameters were carried out. It was found that snow and altitude of study site affect calibration curves of polysulphone dosimeters in comparison to a situation without snow. The median ER, taking into account the whole sample, is 0.60 in winter, with a range of 0.29 to 1.46, and 1.02 in spring, ranging from 0.46 to 1.72. There are no differences in exposures across skiers and instructors in spring while in winter skiers experience lower values. UV exposures are not sensitive to the use of sunscreen across instructor/skier group by day or by seasons or by photo-type. With regard to colorimetric parameters, the main result was that both skiers and instructors had on average significantly lower values of L* and b* after exposure i.e. becoming darker but the inappropriate sunscreen use did not reveal any changes in skin colorimetric parameters except in one spring day. In conclusions UV intensities on the ski-fields are often significantly higher than those on horizontal surfaces. Given the high levels of exposure observed in the present study, dedicated public heath messages on the correct sunscreen use should be adopted
Climate-induced conservation risks of historic reinforced concrete buildings: Preliminary results from literature review
Environmental conditions can favour different kinds of deterioration in historic reinforced concrete structures. This preliminary results from literature review are focused on the climate-induced risks affecting reinforced concrete buildings with respect to mechanical, chemical, and biological deterioration. To this purpose, a three-step process defined by the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) flow diagram, was used leading to the inclusion of 45 documents identified via the search engines Scopus and Web of Science. The outcomes highlight that chemical and mechanical decays are the most investigated ones, being mainly triggered by salt weathering and freezing-thawing cycles. It was found that experimental and theoretical approaches are often coupled to estimate climate-induced deterioration mechanisms, also considering environmental parameters. Finally, the literature search provides some milestones which can be used to evaluate gaps and research needs in the field of climate-induced conservative risks affecting reinforced concrete structures
From 3-Port to New Laparoendoscopic Single-Site (LESS) Cholecystectomy : A Critical Analysis of Available Evidence.
In recent years, laparoendoscopic single-site surgery (LESS) has gained greater interest and diffusion for the treatment of gallstones. This critical review aims to evaluate the feasibility and safety of LESS cholecystectomy versus the 3-port technique (TPT) through a comparative analysis of 5 parameters: mean operative time, intraoperative and postoperative complications, conversion to open, conversion to the 4-trocar technique and postoperative hospital stay. The authors performed a systematic search of the medical literature through a search of PubMed and Ovid EMBASE. Inclusion criteria were as follows: publication date between January 1, 2005, and December 31, 2010; English or Italian language; human participants and series of 20 operations or more. There were 5 manuscripts meeting the inclusion criteria for TPT and 23 for LESS. Only one prospective randomized controlled trial comparing TPT and LESS was identified. Operative time is significantly longer in the single-incision group. Complications and conversion rates to the 4-port technique are higher in LESS. Postoperative hospital stay is similar in the 2 groups. Rate of conversion to open is higher in TPT. Despite the number of publications on LESS cholecystectomy, the vast majority of data available in the literature are from small case series without any comparative data. Although LESS cholecystectomy is a fashionable technique there are few data available for an evidence-based determination as to the real benefits of this technique. Well-designed comparative studies are suggested to validate the clinical benefits and ensure that there are no new complications or added costs associated with the new technique
Indications to total thyroidectomy for multinodular goiter in old patients
Background: In Western society, the percentage of elderly people is
continually growing. The prevalence of goiter increases with the age and it
is estimated that 90% of women over 60 years old and 60% of men over
80 years old have a relief of thyroid nodules. This has great importance for
these patients, because the incidence of malignant transformation is higher
than younger ones and these are often tumor very aggressive patterns. If
thyroidectomy is indicated for patients with suspected neoplasm and severe
obstructive symptoms, their surgery should not be delayed since a late
urgent operation could raise morbidity and mortality risk. The main
indications for young patients are due to obstructive and metabolic causes
over and above suspected cancer.
Total thyroidectomy is considered by many authors as the treatment of
choice.
Materials and methods: 75 elderly patients were submitted to
thyroidectomy. The indications were metabolic (42.6%), obstructive (32%)
and for suspected cancer (25.4%).
Results: The most frequent complications observed with respect to young
patients in different series have been cardiovascular, pulmonary or
urological. Regarding the complications directly related to thyroidectomy,
there were no differences compared to younger groups, except transient
complications (hypoparathyroidism, seroma). In our experience, the main
complication was represented by hypocalcemia (30.6%), permanent in 8% of
cases. Cancer was relieved in 21.3% of cases.
Prognosis has been excellent in most cases, with immediate remission of
symptoms related to thyrotoxicosis and to tracheal and esophageal
compression in almost all symptomatic patients.
Conclusions: Age is an independent prognostic factor for cancers. It has
been demonstrated that elderly patients with PTC that are operated have
better prognosis and quality of life due to the resolution of dyspnea and
dysphagia. In our experience, we think that age is not a contraindication to
thyroid surgery
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