61 research outputs found
Study and development of a remote biometric authentication protocol
This paper reports the phases of study and implementation of a remote biometric authentication protocol developed during my internship at the I.i.t. of the C.n.r. in Pisa. Starting from the study of authentication history we had a look from the first system used since the 60ies to the latest technology; this helped us understand how we could realize a demonstration working protocol that could achieve a web remote authentication granting good reliability: to do this we choosed to modify the SSL handshake with biometric tests and we decided to use smart-cards a secure vault for the sensible biometric data involved. In the first chapter you will find a brief definition of authentication and an introduction on how we can achieve it, with a particular focus on new biometric techniques. In the second chapter there\u27s the history of authentication from the very first password system to actual ones: new token and smart card technolgies are longer stressed in order to introduce the reader to the last chapter. In the third chapter you will find the project framework, the development of our implementation choiches and the source code of the demo project
A high resolution study of complex organic molecules in hot cores
We present the results of a line identification analysis using data from the
IRAM Plateau de Bure Inferferometer, focusing on six massive star-forming hot
cores: G31.41+0.31, G29.96-0.02, G19.61-0.23, G10.62-0.38, G24.78+0.08A1 and
G24.78+0.08A2. We identify several transitions of vibrationally excited methyl
formate (HCOOCH) for the first time in these objects as well as transitions
of other complex molecules, including ethyl cyanide (CHCN), and
isocyanic acid (HNCO). We also postulate a detection of one transition of
glycolaldehyde (CH(OH)CHO) in two new hot cores. We find G29.96-0.02,
G19.61-0.23, G24.78+0.08A1 and 24.78+0.08A2 to be chemically very similar.
G31.41+0.31, however, is chemically different: it manifests a larger chemical
inventory and has significantly larger column densities. We suggest that it may
represent a different evolutionary stage to the other hot cores in the sample,
or it may surround a star with a higher mass. We derive column densities for
methyl formate in G31.41+0.31, using the rotation diagram method, of
10 cm and a T of 170 K. For G29.96-0.02,
G24.78+0.08A1 and G24.78+0.08A2, glycolaldehyde, methyl formate and methyl
cyanide all seem to trace the same material and peak at roughly the same
position towards the dust emission peak. For G31.41+0.31, however,
glycolaldehyde shows a different distribution to methyl formate and methyl
cyanide and seems to trace the densest, most compact inner part of hot cores.Comment: Accepted to MNRA
Observations of CHOH and CHCHO in a Sample of Protostellar Outflow Sources
Iram 30-m Observations towards eight protostellar outflow sources were taken
in the 96-\SI{176}{\giga\hertz} range. Transitions of CHOH and CHCHO
were detected in seven of them. The integrated emission of the transitions of
each species that fell into the observed frequency range were measured and fit
using RADEX and LTE models. Column densities and gas properties inferred from
this fitting are presented. The ratio of the A and E-type isomers of CHOH
indicate that the methanol observed in these outflows was formed on the grain
surface. Both species demonstrate a reduction of terminal velocity in their
line profiles in faster outflows, indicating destruction in the post-shock gas
phase. This destruction, and a near constant ratio of the CHOH and
CHCHO column densities imply it is most likely that CHCHO also forms on
the grain surface.Comment: Accepted for publication in Ap
Metabolism of glutathione in tumour cells as evidenced by 1H MRS
Abstract1H MRS signals of glutathione and of free glutamate were examined in samples from cultured tumour cells, namely MCF-7 from mammary carcinoma and TG98 from malignant glioma, with the aim of relating signal intensities to aspects of GSH metabolism. Spectra of cells harvested at different cell densities suggest that GSH and glu signal intensities are related to cell density and proliferation and their ratio is dependent on the activity of the γ-glutamyl cysteine synthetase. The hypothesis is confirmed by experiments performed on cells treated with buthionine sulfoximine that inhibits the enzyme activity
The origin and structure of clumps along molecular outflows: the test case of CB3
We investigate the origin of the small, chemically rich molecular clumps
observed along the main axis of chemically rich outflows such as CB3 and L1157.
We develop a chemical model where we explore the chemical evolution of these
clumps, assuming they are partially pre-existing to the outflow, or
alternatively newly formed by the impact of the outflow on the surrounding
medium. The effects of the impact of the outflow are reproduced by density and
temperature changes in the clump. We find that the observed abundances of
CH3OH, SO and SO2 are best reproduced by assuming a scenario where the dense
molecular gas observed is probably pre-existing in the interstellar medium
before the formation of their exciting (proto)stars and that the clumpiness and
the rich chemistry of the clumps are a consequence of a pre-existing density
enhancement and of its interaction with the outflow.Comment: 11 pages, 5 figures, accepted by MNRAS; corrected label in figure
The CORONA Business in Modern Cities
As a response to the global outbreak of the SARS-COVID-19 pandemic, authorities have enforced a number of measures including
social distancing, travel restrictions that lead to the “temporary”
closure of activities stemming from public services, schools, industry to local businesses. In this poster we draw the attention to the
impact of such measures on urban environments and activities. For
this, we use crowdsensed information available from datasets like
Google Popular Times and Apple Maps to shed light on the changes
undergone during the outbreak and the recover
VizieR Online Data Catalog: L1157-B1 DCN (2-1) and H13CN (2-1) datacubes (Busquet+, 2017)
IRAM NOEMA observations of DCN(2-1) and H13CN(2-1) towa brightest bow-shock B1 of the L1157 molecular outflow. All data cubes are provided in fits format smoothed to a velocity resolution of 0.5km/s. (2 data files)
Astrochemistry at work in the L1157-B1 shock: acetaldehyde formation
The formation of complex organic molecules (COMs) in protostellar environments is a hotly debated topic. In particular, the relative importance of the gas phase processes as compared to a direct formation of COMs on the dust grain surfaces is so far unknown. We report here the first high-resolution images of acetaldehyde (CH3CHO) emission towards the chemically rich protostellar shock L1157-B1, obtained at 2 mm with the IRAM Plateau de Bure interferometer. Six blueshifted CH3CHO lines with Eu = 26-35 K have been detected. The acetaldehyde spatial distribution follows the young (̃ 2000 yr) outflow cavity produced by the impact of the jet with the ambient medium, indicating that this COM is closely associated with the region enriched by iced species evaporated from dust mantles and released into the gas phase. A high CH3CHO relative abundance, 2-3 × 10-8, is inferred, similarly to what found in hot corinos. Astrochemical modelling indicates that gas phase reactions can produce the observed quantity of acetaldehyde only if a large fraction of carbon, of the order of 0.1 per cent, is locked into iced hydrocarbons
REDISCOVER International Guidelines on the Perioperative Care of Surgical Patients With Borderline-resectable and Locally Advanced Pancreatic Cancer
OBJECTIVE: The REDISCOVER consensus conference aimed at developing and validate guidelines on the perioperative care of patients with borderline resectable (BR-) and locally advanced (LA) pancreatic ductal adenocarcinoma (PDAC).SUMMARY BACKGROUND DATA: Coupled with improvements in chemotherapy and radiation, the contemporary approach to pancreatic surgery supports resection of BR-PDAC and, to a lesser extent, LA-PDAC. Guidelines outlining the selection and perioperative care for these patients are lacking.METHODS: The Scottish Intercollegiate Guidelines Network (SIGN) methodology was used to develop the REDISCOVER guidelines and create recommendations. The Delphi approach was used to reach consensus (agreement ≥80%) among experts. Recommendations were approved after a debate and vote among international experts in pancreatic surgery and pancreatic cancer management. A Validation Committee used the AGREE II-GRS tool to assess the methodological quality of the guidelines. Moreover, an independent multidisciplinary advisory group revised the statements to ensure adherence to non-surgical guidelines.RESULTS: Overall, 34 recommendations were created targeting centralization, training, staging, patient selection for surgery, possibility of surgery in uncommon scenarios, timing of surgery, avoidance of vascular reconstruction, details of vascular resection/reconstruction, arterial divestment, frozen section histology of perivascular tissue, extent of lymphadenectomy, anticoagulation prophylaxis and role of minimally invasive surgery. The level of evidence was however low for 29 of 34 clinical questions. Participants agreed that the most conducive mean to promptly advance our understanding in this field is to establish an international registry addressing this patient population ( https://rediscover.unipi.it/ ).CONCLUSIONS: The REDISCOVER guidelines provide clinical recommendations pertaining to pancreatectomy with vascular resection for patients with BR- and LA-PDAC, and serve as the basis of a new international registry for this patient population.</p
REDISCOVER International Guidelines on the Perioperative Care of Surgical Patients With Borderline-resectable and Locally Advanced Pancreatic Cancer
OBJECTIVE: The REDISCOVER consensus conference aimed at developing and validate guidelines on the perioperative care of patients with borderline resectable (BR-) and locally advanced (LA) pancreatic ductal adenocarcinoma (PDAC).SUMMARY BACKGROUND DATA: Coupled with improvements in chemotherapy and radiation, the contemporary approach to pancreatic surgery supports resection of BR-PDAC and, to a lesser extent, LA-PDAC. Guidelines outlining the selection and perioperative care for these patients are lacking.METHODS: The Scottish Intercollegiate Guidelines Network (SIGN) methodology was used to develop the REDISCOVER guidelines and create recommendations. The Delphi approach was used to reach consensus (agreement ≥80%) among experts. Recommendations were approved after a debate and vote among international experts in pancreatic surgery and pancreatic cancer management. A Validation Committee used the AGREE II-GRS tool to assess the methodological quality of the guidelines. Moreover, an independent multidisciplinary advisory group revised the statements to ensure adherence to non-surgical guidelines.RESULTS: Overall, 34 recommendations were created targeting centralization, training, staging, patient selection for surgery, possibility of surgery in uncommon scenarios, timing of surgery, avoidance of vascular reconstruction, details of vascular resection/reconstruction, arterial divestment, frozen section histology of perivascular tissue, extent of lymphadenectomy, anticoagulation prophylaxis and role of minimally invasive surgery. The level of evidence was however low for 29 of 34 clinical questions. Participants agreed that the most conducive mean to promptly advance our understanding in this field is to establish an international registry addressing this patient population ( https://rediscover.unipi.it/ ).CONCLUSIONS: The REDISCOVER guidelines provide clinical recommendations pertaining to pancreatectomy with vascular resection for patients with BR- and LA-PDAC, and serve as the basis of a new international registry for this patient population.</p
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