94 research outputs found
Gender differences in V˙O2 and HR kinetics at the onset of moderate and heavy exercise intensity in adolescents
The majority of the studies on (V)over dotO(2) kinetics in pediatric populations investigated gender differences in prepubertal children during submaximal intensity exercise, but studies are lacking in adolescents. The purpose of this study was to test the hypothesis that gender differences exist in the (V)over dotO(2) and heart rate (HR) kinetic responses to moderate (M) and heavy (H) intensity exercise in adolescents. Twenty-one healthy African-American adolescents (9 males, 15.8 +/- 1.1 year; 12 females, 15.7 +/- 1 year) performed constant work load exercise on a cycle ergometer at M and H. The (V)over dotO(2) kinetics of the male group was previously analyzed (Lai et al., Appl. Physiol. Nutr. Metab. 33:107-117, 2008b). For both genders, (V)over dotO(2) and HR kinetics were described with a single exponential at M and a double exponential at H. The fundamental time constant (tau(1)) of (V)over dotO(2) was significantly higher in female than male at M (45 +/- 7 vs. 36 +/- 11 sec, P < 0.01) and H (41 +/- 8 vs. 29 +/- 9 sec, P < 0.01), respectively. The functional gain (G(1)) was not statistically different between gender at M and statistically higher in females than males at H: 9.7 +/- 1.2 versus 10.9 +/- 1.3 mL min(-1) W-1, respectively. The amplitude of the slow component was not significantly different between genders. The HR kinetics were significantly (tau(1), P < 0.01) slower in females than males at M (61 +/- 16 sec vs. 45 +/- 20 sec, P < 0.01) and H (42 +/- 10 sec vs. 30 +/- 8 sec, P = 0.03). The G(1) of HR was higher in females than males at M: 0.53 +/- 0.11 versus 0.98 +/- 0.2 bpm W-1 and H: 0.40 +/- 0.11 versus 0.73 +/- 0.23 bpm W-1, respectively. Gender differences in the (V)over dotO(2) and HR kinetics suggest that oxygen delivery and utilization kinetics of female adolescents differ from those in male adolescents
Insights into the reionization epoch from cosmic-noon-CIV emitters in the VANDELS survey
Recently, intense emission from nebular C III] and C IV emission lines have
been observed in galaxies in the epoch of reionization () and have been
proposed as the prime way of measuring their redshift and studying their
stellar populations. These galaxies might represent the best examples of cosmic
reionizers, as suggested by recent low-z observations of Lyman Continuum
emitting galaxies, but it is hard to directly study the production and escape
of ionizing photons at such high redshifts. The ESO spectroscopic public survey
VANDELS offers the unique opportunity to find rare examples of such galaxies at
cosmic noon (), thanks to the ultra deep observations available. We
have selected a sample of 39 galaxies showing C IV emission, whose origin
(after a careful comparison to photoionization models) can be ascribed to star
formation and not to AGN. By using a multi-wavelength approach, we determine
their physical properties including metallicity and ionization parameter and
compare them to the properties of the parent population to understand what are
the ingredients that could characterize the analogs of the cosmic reionizers.
We find that C IV emitters are galaxies with high photons production efficiency
and there are strong indications that they might have also large escape
fraction: given the visibility of C IV in the epoch of reionization this could
become the best tool to pinpoint the cosmic reioinzers.Comment: 15 pages, 10 figures, resubmitted to A&A after addressing the referee
comment
The ionizing photon production efficiency of bright z2-5 galaxies
We investigate the production efficiency of ionizing photons ()
of 1174 galaxies with secure redshift at z=2-5 from the VANDELS survey to
determine the relation between ionizing emission and physical properties of
bright and massive sources. We constrain and galaxy physical
parameters by means of spectro-photometric fits performed with the BEAGLE code.
The analysis exploits the multi-band photometry in the VANDELS fields, and the
measurement of UV rest-frame emission lines (CIII], HeII, OIII]) from deep VIMOS spectra. We find no clear evolution
of with redshift within the probed range. The ionizing efficiency
slightly increases at fainter , and bluer UV slopes, but these trends
are less evident when restricting the analysis to a complete subsample at
log(M/M)9.5. We find a significant trend of increasing
with increasing EW(Ly), with an average
log(/Hz erg)25 at EW50\AA, and a higher ionizing
efficiency for high-EW CIII] and OIII] emitters.
The most significant correlations are found with respect to stellar mass,
specific star-formation rate (sSFR) and SFR surface density ().
The relation between and sSFR shows a monotonic increase from
log(/Hz erg) 24.5 at log(sSFR)-9.5 to
25.5 at log(sSFR)-7.5, a low scatter and little dependence
on mass. The objects above the main-sequence of star-formation consistently
have higher-than-average . A clear increase of with
is also found, with log(/Hz erg)25 for
objects at 10 M.(Abridged)Comment: 11 pages, 9 figures, accepted for publication in A&
Pathological Complete Response in Patients With Resected Pancreatic Adenocarcinoma After Preoperative Chemotherapy
Importance: Preoperative chemo(radio)therapy is increasingly used in patients with localized pancreatic adenocarcinoma, leading to pathological complete response (pCR) in a small subset of patients. However, multicenter studies with in-depth data about pCR are lacking. Objective: To investigate the incidence, outcome, and risk factors of pCR after preoperative chemo(radio)therapy. Design, Setting, and Participants: This observational, international, multicenter cohort study assessed all consecutive patients with pathology-proven localized pancreatic adenocarcinoma who underwent resection after 2 or more cycles of chemotherapy (with or without radiotherapy) in 19 centers from 8 countries (January 1, 2010, to December 31, 2018). Data collection was performed from February 1, 2020, to April 30, 2022, and analyses from January 1, 2022, to December 31, 2023. Median follow-up was 19 months. Exposures: Preoperative chemotherapy (with or without radiotherapy) followed by resection. Main Outcomes and Measures: The incidence of pCR (defined as absence of vital tumor cells in the sampled pancreas specimen after resection), its association with OS from surgery, and factors associated with pCR. Factors associated with overall survival (OS) and pCR were investigated with Cox proportional hazards and logistic regression models, respectively. Results: Overall, 1758 patients (mean [SD] age, 64 [9] years; 879 [50.0%] male) were studied. The rate of pCR was 4.8% (n = 85), and pCR was associated with OS (hazard ratio, 0.46; 95% CI, 0.26-0.83). The 1-, 3-, and 5-year OS rates were 95%, 82%, and 63% in patients with pCR vs 80%, 46%, and 30% in patients without pCR, respectively (P < .001). Factors associated with pCR included preoperative multiagent chemotherapy other than (m)FOLFIRINOX ([modified] leucovorin calcium [folinic acid], fluorouracil, irinotecan hydrochloride, and oxaliplatin) (odds ratio [OR], 0.48; 95% CI, 0.26-0.87), preoperative conventional radiotherapy (OR, 2.03; 95% CI, 1.00-4.10), preoperative stereotactic body radiotherapy (OR, 8.91; 95% CI, 4.17-19.05), radiologic response (OR, 13.00; 95% CI, 7.02-24.08), and normal(ized) serum carbohydrate antigen 19-9 after preoperative therapy (OR, 3.76; 95% CI, 1.79-7.89). Conclusions and Relevance: This international, retrospective cohort study found that pCR occurred in 4.8% of patients with resected localized pancreatic adenocarcinoma after preoperative chemo(radio)therapy. Although pCR does not reflect cure, it is associated with improved OS, with a doubled 5-year OS of 63% compared with 30% in patients without pCR. Factors associated with pCR related to preoperative chemo(radio)therapy regimens and anatomical and biological disease response features may have implications for treatment strategies that require validation in prospective studies because they may not universally apply to all patients with pancreatic adenocarcinoma.</p
Pathological Complete Response in Patients With Resected Pancreatic Adenocarcinoma After Preoperative Chemotherapy
Importance: Preoperative chemo(radio)therapy is increasingly used in patients with localized pancreatic adenocarcinoma, leading to pathological complete response (pCR) in a small subset of patients. However, multicenter studies with in-depth data about pCR are lacking. Objective: To investigate the incidence, outcome, and risk factors of pCR after preoperative chemo(radio)therapy. Design, Setting, and Participants: This observational, international, multicenter cohort study assessed all consecutive patients with pathology-proven localized pancreatic adenocarcinoma who underwent resection after 2 or more cycles of chemotherapy (with or without radiotherapy) in 19 centers from 8 countries (January 1, 2010, to December 31, 2018). Data collection was performed from February 1, 2020, to April 30, 2022, and analyses from January 1, 2022, to December 31, 2023. Median follow-up was 19 months. Exposures: Preoperative chemotherapy (with or without radiotherapy) followed by resection. Main Outcomes and Measures: The incidence of pCR (defined as absence of vital tumor cells in the sampled pancreas specimen after resection), its association with OS from surgery, and factors associated with pCR. Factors associated with overall survival (OS) and pCR were investigated with Cox proportional hazards and logistic regression models, respectively. Results: Overall, 1758 patients (mean [SD] age, 64 [9] years; 879 [50.0%] male) were studied. The rate of pCR was 4.8% (n = 85), and pCR was associated with OS (hazard ratio, 0.46; 95% CI, 0.26-0.83). The 1-, 3-, and 5-year OS rates were 95%, 82%, and 63% in patients with pCR vs 80%, 46%, and 30% in patients without pCR, respectively (P < .001). Factors associated with pCR included preoperative multiagent chemotherapy other than (m)FOLFIRINOX ([modified] leucovorin calcium [folinic acid], fluorouracil, irinotecan hydrochloride, and oxaliplatin) (odds ratio [OR], 0.48; 95% CI, 0.26-0.87), preoperative conventional radiotherapy (OR, 2.03; 95% CI, 1.00-4.10), preoperative stereotactic body radiotherapy (OR, 8.91; 95% CI, 4.17-19.05), radiologic response (OR, 13.00; 95% CI, 7.02-24.08), and normal(ized) serum carbohydrate antigen 19-9 after preoperative therapy (OR, 3.76; 95% CI, 1.79-7.89). Conclusions and Relevance: This international, retrospective cohort study found that pCR occurred in 4.8% of patients with resected localized pancreatic adenocarcinoma after preoperative chemo(radio)therapy. Although pCR does not reflect cure, it is associated with improved OS, with a doubled 5-year OS of 63% compared with 30% in patients without pCR. Factors associated with pCR related to preoperative chemo(radio)therapy regimens and anatomical and biological disease response features may have implications for treatment strategies that require validation in prospective studies because they may not universally apply to all patients with pancreatic adenocarcinoma.</p
Enterprise Culture and the Arts: Neo-Liberal Values and British Art Institutions
Neoliberal discourse has spread from the economic realm into all parts of society. This chapter discusses the current situation of neoliberal discourses and their effects on the arts, focusing on the United Kingdom. It also examines the historical development of British cultural policy, highlighting trends toward the marketization of the arts, increasing government intervention, and a growing emphasis on managerialism. The analysis shows that British arts organizations have been deeply affected by state and corporate interests. The chapter draws on the work of Pierre Bourdieu, who describes the field of cultural production as containing two poles that are autonomous or heteronomous. By tracing British cultural policy as it came to favor enterprise culture, the chapter demonstrates an increasing loss of autonomy in the arts
Non-AIDS defining cancers in the D:A:D Study-time trends and predictors of survival : a cohort study
BACKGROUND:Non-AIDS defining cancers (NADC) are an important cause of morbidity and mortality in HIV-positive individuals. Using data from a large international cohort of HIV-positive individuals, we described the incidence of NADC from 2004-2010, and described subsequent mortality and predictors of these.METHODS:Individuals were followed from 1st January 2004/enrolment in study, until the earliest of a new NADC, 1st February 2010, death or six months after the patient's last visit. Incidence rates were estimated for each year of follow-up, overall and stratified by gender, age and mode of HIV acquisition. Cumulative risk of mortality following NADC diagnosis was summarised using Kaplan-Meier methods, with follow-up for these analyses from the date of NADC diagnosis until the patient's death, 1st February 2010 or 6 months after the patient's last visit. Factors associated with mortality following NADC diagnosis were identified using multivariable Cox proportional hazards regression.RESULTS:Over 176,775 person-years (PY), 880 (2.1%) patients developed a new NADC (incidence: 4.98/1000PY [95% confidence interval 4.65, 5.31]). Over a third of these patients (327, 37.2%) had died by 1st February 2010. Time trends for lung cancer, anal cancer and Hodgkin's lymphoma were broadly consistent. Kaplan-Meier cumulative mortality estimates at 1, 3 and 5 years after NADC diagnosis were 28.2% [95% CI 25.1-31.2], 42.0% [38.2-45.8] and 47.3% [42.4-52.2], respectively. Significant predictors of poorer survival after diagnosis of NADC were lung cancer (compared to other cancer types), male gender, non-white ethnicity, and smoking status. Later year of diagnosis and higher CD4 count at NADC diagnosis were associated with improved survival. The incidence of NADC remained stable over the period 2004-2010 in this large observational cohort.CONCLUSIONS:The prognosis after diagnosis of NADC, in particular lung cancer and disseminated cancer, is poor but has improved somewhat over time. Modifiable risk factors, such as smoking and low CD4 counts, were associated with mortality following a diagnosis of NADC
Antenna Array Signal Processing for Multistatic Radar Systems
The introductions of Digital Beam Forming (DBF), original signal exploitation and waveform multiplexing techniques have led to the design of novel radar concepts. Passive Coherent Locator (PCL) and Multiple-Input Multiple-Output (MIMO) sensors are two examples of innovative approaches. Beside the inherent benefits of this class of sensors, related to the use of emitters of opportunity and the waveform diversity for the PCL and the MIMO cases respectively, an additional gain is achieved by using ad-hoc array signal processing techniques. The well-known advantages provided by the antenna arrays, or phased arrays, are, among other, the possibility of synthesising arbitrarily steered beams, especially in the case of DBF, the capability of shaping the array pattern sidelobes region and the opportunity of placing nulls towards specific directions. The last feature allows suppressing, or mitigating, the echoes of unwanted signals (clutter, jammer, interferences) that are present inside the radar scenario and that can degrade the detection performance of the system. With DBF, the interferences suppression can adaptively be done in real time. This thesis has focused on the development of novel array processing algorithms, with emphasis on antenna pattern optimisation. Also, attention was paid to resolution enhancement and clutter suppression techniques exploiting the available radar architectures. A PCL and a MIMO array system have been investigated in order to validate the proposed techniques. Specifically, the first part of the thesis deals with the development of the array signal processing chain of a PCL system based on a circular array. The performance of digital beamforming algorithms highly depends on the behavior of the antenna section of the array; indeed, an inaccurate characterisation of the element channels and their mutual influence degrades the shape of the synthesised array pattern. A complete analysis of the circular array is presented in the text and a technique for the mutual coupling compensation, based on an optimisation approach, was retrieved. The effectiveness of the method was validated. Furthermore, a new pattern shaping technique for the sidelobes reduction was developed. Due to the poor angular resolution of the PCL array, the criteria for estimating the quality of the retrieved algorithm was represented by the achievable sidelobes suppression level for a given angular resolution. A comparison with the phase modes approach has proven the better performance of the proposed method. Concerning the validation of the PCL system, the entire signal processing chain of the sensor was developed and the related behavior was successfully assessed by the comparison with the ground truth data provided by an ADSB transponder. The second part of the thesis refers to coherent MIMO radars and to the benefifits they provide with respect to conventional array-based radars. The linear array confifiguration was taken as reference and a MIMO test board, the RADOCA system, has been realised and studied. By first recalling the peculiarity of such systems, i.e. the possibility of synthesising virtual array structures, the research activity has investigated the effect that illumination errors produce on the related pattern behavior. The analytical expression of the errors affected pattern was retrieved and the comparison with conventional linear array systems showed the higher degradation they produce on MIMO based arrays. The focus was then moved to the identification of calibration and array processing techniques, capable of exploiting both the MIMO radar principle and the additional degrees of freedom provided by the virtual channels. By referring to the RADOCA demonstrator, a calibration procedure was retrieved and validated thanks to real data acquisitions. Then, with the aim of enhancing the system performance, two objectives were reached: the extension of the maximum unambiguous Doppler interval, by means of a random selection of the radar transmitter sequence, and the identification of a novel 2D high resolution technique based on the MUSIC algorithm. The comparisons with traditional approaches highlighted the benefits of the proposed techniques.Geoscience and Remote SensingCivil Engineering and Geoscience
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