1,135 research outputs found
Time properties of the the rho-class burst of the microquasar GRS 1915+105 observed with BeppoSAX in April 1999
We present a temporal analysis of a BeppoSAX observation of GRS 1915+105
performed on April 13, 1999 when the source was in the rho class, which is
characterised by quasi-regular bursting activity. The aim of the present work
is to confirm and extend the validity of the results obtained with a BeppoSAX
observation performed on October 2000 on the recurrence time of the burst and
on the hard X-ray delay. We divided the entire data set into several series,
each corresponding to a satellite orbit, and performed the Fourier and wavelet
analysis and the limit cycle mapping technique using the count rate and the
average energy as independent variables. We found that the count rates
correlate with the recurrence time of bursts and with hard X-ray delay,
confirming the results previously obtained. In this observation, however, the
recurrence times are distributed along two parallel branches with a constant
difference of 5.2+/-0.5 s.Comment: Accepted for publication in Section 7. Stellar structure and
evolution of Astronomy and Astrophysic
Lyapunov functions for a non-linear model of the X-ray bursting of the microquasar GRS 1915+105
This paper introduces a biparametric family of Lyapunov functions for a
non-linear mathematical model based on the FitzHugh-Nagumo equations able to
reproduce some main features of the X-ray bursting behaviour exhibited by the
microquasar GRS 1915+105. These functions are useful to investigate the
properties of equilibrium points and allow us to demonstrate a theorem on the
global stability. The transition between bursting and stable behaviour is also
analyzed.Comment: Published on International Journal of Non-Linear Mechanics, vol. 88,
pp. 142-14
Role of systemic inflammation scores in pulmonary metastasectomy for colorectal cancer
Background: Patients with pulmonary metastases from colorectal cancer can
benefit from surgical removal.However, the biological determinants of postsurgical
outcome are not completely elucidated. We evaluated the role of host systemic
inflammation status in this setting.
Methods: The modified Glasgow prognostic score (based on serum C-reactive
protein and albumin levels) and the neutrophil-to-lymphocyte (NTL) ratio were
obtained from 44 patients who received curative-intent metastasectomy, and were
used as indicators of systemic inflammation status.We tested the impact of both of
these parameters on overall survival (OS) and progression-free survival (PFS), as
well as their correlation with other well-known prognosticators.
Results: Five-year PFS and OS rates were 18% and 49%, respectively. At univariate
analysis,multiple metastases, disease-free interval <36 months, and a Glasgow score
of 2 (P = 0.031)were significantly associated to aworse PFS rate.A NTL ratio >3 predicted
disease progression in the short-term(P = 0.036), but the effect on late events
was weaker (P = 0.079). Factors associated with worse OS were multiple metastasis
(P = 0.002), elevated carcinoembryonic antigen (P = 0.009), a Glasgowscore of 2 (P =
0.029), and a faster metastasis growth (P = 0.008).At Cox regression analysis, neither
a Glasgow score of 2, nor elevated NTL ratio showed an independent effect on survival
rates.
Conclusions: Systemic inflammation scores did not perform well as independent
survival prognosticators in patients undergoing curative-intent pulmonary
metastasectomy. Further investigation is warranted to evaluate whether these measurements
could still be useful when restricting the analysis to specific patient subcategories
or to diverse postoperative phases
Excitation transport with collective radiative decay
We investigate a one-dimensional quantum emitter chain where transport of excitations and correlations takes place via nearest neighbor, dipole-dipole interactions. In the presence of collective radiative emission, we show that a phase imprinting wavepacket initialization procedure can lead to subradiant transport and can preserve quantum correlations. In the context of cavity mediated transport, where emitters are coupled to a common delocalized optical mode, we analyze the effect of frequency disorder and nonidentical photon-emitter couplings on excitation transport
The complex time behaviour of the microquasar GRS 1915+105 in the \rho-class observed with BeppoSAX. III: The hard X-ray delay and limit cycle mapping
The microquasar GRS1915+105 was observed by BeppoSAX in October 2000 for
about ten days while the source was in \rho-mode, which is characterized by a
quasi-regular type I bursting activity. This paper presents a systematic
analysis of the delay of the hard and soft X-ray emission at the burst peaks.
The lag, also apparent from the comparison of the [1.7-3.4] keV light curves
with those in the [6.8-10.2] keV range, is evaluated and studied as a function
of time, spectral parameters, and flux. We apply the limit cycle mapping
technique, using as independent variables the count rate and the mean photon
rate. The results using this technique were also cross-checked using a more
standard approach with the cross-correlation methods. Data are organized in
runs, each relative to a continuous observation interval. The detected
hard-soft delay changes in the course of the pointing from about 3 s to about
10 s and presents a clear correlation with the baseline count rate.Comment: accepted for publication in A&
Duration of air leak is reduced after awake nonresectional lung volume reduction surgery
OBJECTIVE:
Prolonged air leak occurs frequently after lung volume reduction surgery (LVRS) and can negatively affect both morbidity and hospital stay. We hypothesised that awake nonresectional LVRS could reduce the duration of air leak in emphysema patients.
METHODS:
This analysis included 66 patients undergoing awake, unilateral plication of the most emphysematous lung regions under sole epidural anaesthesia. Primary outcome measure was the rate of prolonged (>7 days) air leak; secondary outcome measures included the mean duration of air leak, hospital stay and early discharges (<or=4 days). All results were retrospectively compared with those of a similar control group undergoing resectional LVRS under general anaesthesia.
RESULTS:
Intergroup comparisons showed that demographics and baseline data were well matched. Prolonged air leak occurred in 12 patients (18%) in the awake group versus 27 patients (40%) in the control group (p=0.007) with a mean duration of 5.2+/-6.5 days versus 7.9+/-7.6 days (p<0.0002). Mean hospital stay was significantly shorter in the awake group (6.3+/-2.8 days vs 9.2+/-5.6 days, p<0.0001). At univariate analysis, resectional LVRS (p=0.007), higher severity of emphysema (p<0.0001) and lower diffusion capacity for carbon monoxide (p=0.0001) correlated with occurrence of prolonged air leak; however, logistic regression indicated high severity of emphysema as the most important factor predicting prolonged air leak (odds ratio=4.85, p<0.0001). At 6 months, dyspnoea index, FEV1 and 6 min walking test improved significantly in both study groups.
CONCLUSIONS:
In this study, awake nonresectional LVRS was associated with a lower rate of prolonged air leak and a shorter hospital stay than the standard resectional technique
Company Competitiveness as a Variable Success Strategy for the Territory and the Environment
Supporting the fortunes of the Made in Italy agri-food brand are the best quality products which can be found throughout the Italian territory and which, in many cases, derive from Southern Italy, with a particularly interesting role assumed by Campania and Sicily.The Sicily Region boasts a varied and peculiar food and wine heritage, especially from a qualitative point of view, the Born in Sicily brand, made with excellent raw materials which constitute and support the development of important production lines within the agro-industrial sector.Among the most important food industries in Italy and on the island, there are some operating in the confectionery industry. Today the fast-growing confectionery industry contributes a great deal to the agri-food system.This study analyzes the agri-food system both in Italy and Sicily, highlighting the main sectors which contribute to make the Made in Italy brand competitive around the world and how companies have succeeded in starting up some interesting internationalization processes.This the reason why a specific case regarding a Sicilian confectionery industry is examined so as to understand how it was able to create such a successful innovative product, establishing itself on both the national and international market.The results show that entrepreneurial skills contribute a great deal to creating business competitiveness and territorial development
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