770 research outputs found
The double RGB in M 2: C, N, Sr and Ba abundances
The globular cluster M 2 has a photometrically detected double red giant
branch (RGB) sequence. We investigate here the chemical differences between the
two RGBs in order to gain insight in the star formation history of this
cluster. The low-resolution spectra, covering the blue spectral range, were
collected with the MODS spectrograph on the LBT, and analyzed via spectrum
synthesis technique. The high quality of the spectra allows us to measure C, N,
Ba, and Sr abundances relative to iron for 15 RGB stars distributed along the
two sequences. We add to the MODS sample C and N measurements for 35 additional
stars belonging to the blue RGB sequence, presented in Lardo et al. (2012). We
find a clear separation between the two groups of stars in s-process elements
as well as C and N content. Both groups display a C-N anti-correlation and the
red RGB stars are on average richer in C and N with respect to the blue RGB.
Our results reinforce the suggestion that M2 belongs to the family of globular
clusters with complex star formation history, together with Omega Cen, NGC
1851, and M 22.Comment: 11 pages, 8 figures. Accepted for publication in MNRA
Challenges and opportunities for more efficient water use and circular wastewater management. The case of Campania Region, Italy
By 2050, global demand for water is expected to increase by some 55% due to population growth and urbanization. The utilization of large amounts of freshwater in the world, generate huge volumes of wastewater of which, globally, more than 80% is discharged without treatment, thus causing impacts on aquatic ecosystems, human health and economic productivity. More sustainable practices of wastewater management are expected as a way towards circular bioeconomy (CBE) processes, whose goal is to implement closed systems promoting the systematic use of recycling, reuse and recovery of bioproducts and by-products and the reduction of waste generation. This approach, if adopted in the water and wastewater sector, can ensure environmental, economic and social benefits. The reuse of wastewater, on the one hand, reduces the volume of wastewater and the pressure on water bodies; on the other hand, the recovery of nutrients (P or N) and/or other high value bioproducts (biogas, cellulose, biopolymers) from wastewater offers numerous advantages in terms of supplying new raw bio-based materials that can be refed back to supply chains (thus substituting fossil resources) and, at the same time, producing cleaner water to be reused. Nevertheless, while in Europe many industries have demonstrated the ability to recycle and reuse water, in many regions of Italy the sustainable management of water and wastewater is not yet consolidated. In this study we explore the available technological, economic and environmental options concerning water use and wastewater treatment and we apply them to design appropriate scenarios for improved use efficiency and circular management. A comprehensive literature review of the most promising wastewater treatment processes for resources and energy valorization was conducted. The recovery of PHAs, struvite, nitrogen and algal biomass, as potential substitutes for conventional PET, phosphate and nitrogen chemical fertilizers and electricity, respectively, in addition to reusable treated water, were hypothesized and carefully discussed. Resulting scenarios are tested against the present situation of Campania Region (situated in Southern Italy) based on population and demand statistics, in order to develop strategies and policies potentially applicable locally and elsewhere
Risk-adjusted performance indicators in life insurance
The paper approaches the potential of risk-adjusted performance indicators in life insurance, with special reference to a structured policy. The final issue is the computation of risk adjusted indicators as a tool to evaluate the portfolio given a policy structure. The
computation of such indicator could be suitable for the appraisal of both portfolio optimization and potential profits of the structured policy. The selection tool is put into an asset and liability management decision making context, where the relationship between
expected surplus and capital at risk are compared.
The analysis is applied to a structured temporary annuity and is treated by means of Monte
Carlo simulations
Conservação pós-colheita de melão Galia 'Solar King' a temperatura ambiente sob influência de 1 - MCP (1 - metilciclopropeno).
O objetivo deste trabalho foi avaliar o efeito de doses de 1-MCP (0, 100, 300 e 900 ppb) no comportamento respiratório e na qualidade pós-colheita de melão Galia 'Solar King', em temperatura ambiente (24,5 ± 0,9ºC e 86,4 ± 7,9%). O 1-MCP reduziu a atividade respiratória e atrasou o pico de produção de etileno mas não afetou o teor de sólidos solúveis totais, a acidez total titulável, o pH e a aparência externa. Contudo, a aparência interna dos frutos tratados foi melhor, principalmente na concentração de 300 ppb. Além da melhor aparência, aquela dose possibilitou atividade respiratória mais baixaSuplemento 2. Edição do 42 Congresso Brasileiro de Olericultura e 11 Congresso Latino Americano de Horticultura, Uberlândia, jul. 2002
Avaliação do amaciamento de melão Galia 'Solar King' tratado com 1-MCP (1-metilciclopropreno) através da firmeza da polpa e tomografia de RM.
Objetivou-se avaliar o efeito de doses de 1-MCP (0, 100, 300 e 900 ppb) sobre o amaciamento da polpa (firmeza e tomografia de RM) e a formação da região de abscisão do pedúnculo, durante o armazenamento (24,5 ± 0,9ºC e 86,4 ± 7,9%) de melão Galia 'Solar King'. O 1-MCP atrasou a evolução de ambas as variáveis. As melhores respostas foram obtidas com 300 e 900 ppb, recomendando-se a primeira como dose econômica
Somatic instability of the expanded GAA triplet-repeat sequence in Friedreich ataxia progresses throughout life
Friedreich ataxia (FRDA) patients are homozygous for expanded GAA triplet-repeat
alleles in the FXN gene. Primary neurodegeneration involving the dorsal root ganglia
(DRG) results in progressive ataxia. While it is known that DRG are inherently sensitive
to frataxin deficiency, recent observations also indicate that they show age-dependent,
further expansion of the GAA triplet-repeat mutation. Whether somatic instability is
progressive has not been systematically investigated in FRDA patients. Small pool PCR
analysis of ~2300 individual molecules from tissues of an 18-week fetus, homozygous
for expanded alleles, revealed very low levels of instability compared with adult-derived
tissues (4.2% versus 30.6%, P<0.0001). Mutation load in blood samples from multiple
patients and carriers increased significantly with age, ranging from 7.5% at 18-weeks
gestation to 78.7% at 49y (R=0.91; P=0.0001). Therefore, somatic instability in FRDA
occurs mostly after early embryonic development and progresses throughout life,
lending further support to the role of postnatal somatic instability in disease
pathogenesis
The Gaia spectrophotometric standard stars survey -II. Instrumental effects of six ground-based observing campaigns
The Gaia SpectroPhotometric Standard Stars (SPSS) survey started in 2006, it
was awarded almost 450 observing nights, and accumulated almost 100,000 raw
data frames, with both photometric and spectroscopic observations. Such large
observational effort requires careful, homogeneous, and automated data
reduction and quality control procedures. In this paper, we quantitatively
evaluate instrumental effects that might have a significant (i.e.,1%)
impact on the Gaia SPSS flux calibration. The measurements involve six
different instruments, monitored over the eight years of observations dedicated
to the Gaia flux standards campaigns: DOLORES@TNG in La Palma, EFOSC2@NTT and
ROSS@REM in La Silla, [email protected] in Calar Alto, BFOSC@Cassini in Loiano, and
[email protected] in San Pedro Martir. We examine and quantitatively evaluate the
following effects: CCD linearity and shutter times, calibration frames
stability, lamp flexures, second order contamination, light polarization, and
fringing. We present methods to correct for the relevant effects, which can be
applied to a wide range of observational projects at similar instruments.Comment: 16 pages, 13 figures, accepted for publication in Astron. Nach
Automatically Extracted Machine Learning Features from Preoperative CT to Early Predict Microvascular Invasion in HCC: The Role of the Zone of Transition (ZOT)
Background: Microvascular invasion (MVI) is a consolidated predictor of hepatocellular carcinoma (HCC) recurrence after treatments. No reliable radiological imaging findings are available for preoperatively diagnosing MVI, despite some progresses of radiomic analysis. Furthermore, current MVI radiomic studies have not been designed for small HCC nodules, for which a plethora of treatments exists. This study aimed to identify radiomic MVI predictors in nodules <= 3.0 cm by analysing the zone of transition (ZOT), crossing tumour and peritumour, automatically detected to face the uncertainties of radiologist's tumour segmentation. Methods: The study considered 117 patients imaged by contrast-enhanced computed tomography; 78 patients were finally enrolled in the radiomic analysis. Radiomic features were extracted from the tumour and the ZOT, detected using an adaptive procedure based on local image contrast variations. After data oversampling, a support vector machine classifier was developed and validated. Classifier performance was assessed using receiver operating characteristic (ROC) curve analysis and related metrics. Results: The original 89 HCC nodules (32 MVI+ and 57 MVI-) became 169 (62 MVI+ and 107 MVI-) after oversampling. Of the four features within the signature, three are ZOT heterogeneity measures regarding both arterial and venous phases. On the test set (19MVI+ and 33MVI-), the classifier predicts MVI+ with area under the curve of 0.86 (95%CI (0.70-0.93), p similar to 10(-5)), sensitivity = 79% and specificity = 82%. The classifier showed negative and positive predictive values of 87% and 71%, respectively. Conclusions: The classifier showed the highest diagnostic performance in the literature, disclosing the role of ZOT heterogeneity in predicting the MVI+ status
SN 2002lt and GRB 021211: a SN/GRB Connection at z = 1
We present spectroscopic and photometric observations of the afterglow of GRB
021211 and the discovery of its associated supernova, SN 2002lt. The spectrum
shows a broad feature (FWHM = 150 A), around 3770 A (in the rest-frame of the
GRB), which we interpret as Ca H+K blueshifted by 14400 km/s. Potential sources
of contamination due to the host galaxy and/or residuals of telluric absorption
have been analyzed and ruled out. Overall, the spectrum shows a suggestive
resemblance with the one of the prototypical type-Ic SN 1994I. This might
indicate that GRBs are produced also by standard type-Ic supernovae.Comment: 6 pages, 5 color figures. Proceedings of the 2003 GRB Conference
(Santa Fe, NM, 2003 Sep 8-12). Needs aipprocs LaTeX clas
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