This paper proposes efficient batch-based and online strategies for kernel regression over graphs (KRG). The proposed algorithms do not require the input signal to be a graph signal, whereas the ...target signal is defined over the graph. We first use random Fourier features (RFF) to tackle the complexity issues associated with kernel methods employed in the conventional KRG. For batch-based approaches, we also propose an implementation that reduces complexity by avoiding the inversion of large matrices. Then, we derive two distinct online strategies using RFF, namely, the mini-batch gradient KRG (MGKRG) and the recursive least squares KRG (RLSKRG). The stochastic-gradient KRG (SGKRG) is introduced as a particular case of the MGKRG. The MGKRG and the SGKRG are low-complexity algorithms that employ stochastic gradient approximations in the regression-parameter update. The RLSKRG is a recursive implementation of the RFF-based batch KRG. A detailed stability analysis is provided for the proposed online algorithms, including convergence conditions in both mean and mean-squared senses. A discussion on complexity is also provided. Numerical simulations include a synthesized-data experiment and real-data experiments on temperature prediction, brain activity estimation, and image reconstruction. Results show that the RFF-based batch implementation offers competitive performance with a reduced computational burden when compared to the conventional KRG. The MGKRG offers a convenient trade-off between performance and complexity by varying the number of mini-batch samples. The RLSKRG has a faster convergence than the MGKRG and matches the performance of the batch implementation.
Skin and feather characteristics, which play a critical role in body temperature maintenance, can be affected by incubation circumstances, such as incubation temperature. However, no study to date ...has assessed the influence of incubation temperature during the fetal stage on morphometric characteristics and vascular development of the skin, feather characteristics, and their relationship to hormone levels and preferred temperature in later life in chickens. Broiler breeder eggs were exposed to low (36°C), control (37.5°C), or high (39°C) temperatures (treatments LT, CK, and HT, respectively) from day 13 of incubation onward, because it is known that the endocrine axes are already established at this time. During this period, eggshell temperature of HT eggs (38.8±0.33°C) was higher than of LT (37.4±0.08°C) and CK eggs (37.8 ±0.15°C). The difference between eggshell and incubator air temperature diminished with the increasing incubation temperature, and was approximately zero for HT. HT hatchlings had higher surface temperature on the head, neck, and back, and thinner and more vascularized skin than did CK and LT hatchlings. No differences were found among treatments for body weight, total feather weight, number and length of barbs, barbule length, and plasma T4 concentration. LT hatchlings showed lower plasma T3 and GH, as well as lower T3/T4 ratio and decreased vascularity in the neck, back, and thigh skin compared to CK hatchlings. On the other hand, HT hatchlings had decreased skin thickness and increased vascularity, and preferred a higher ambient temperature compared to CK and HT hatchlings. In addition, for all treatments, surface temperature on the head was higher than of the other body regions. We conclude that changes in skin thickness and vascularity, as well as changes in thyroid and growth hormone levels, are the result of embryonic strategies to cope with higher or lower than normal incubation temperatures. Additionally exposure to increased temperature during incubation is an environmental factor that can exert early-life influence on ambient temperature preference of broiler hatchlings in later life.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Corynebacterium diphtheriae (C. diphtheriae) infections, usually related to upper airways involvement, could be highly invasive. Especially in developing countries, non-toxigenic C. diphtheriae ...strains are now emerging as cause of invasive disease like endocarditis. The present case stands out for reinforcing the high virulence of this pathogen, demonstrated by the multiple systemic embolism and severe valve deterioration. It also emphasizes the importance of a coordinated interdisciplinary work to address all these challenges related to infectious endocarditis.
A 21-year-old male cocaine drug abuser presented to the emergency department with a 1-week history of fever, asthenia and dyspnea. His physical examination revealed a mitral systolic murmur, signs of acute arterial occlusion of the left lower limb, severe arterial hypotension and acute respiratory failure, with need of vasoactive drugs, orotracheal intubation/mechanical ventilation, empiric antimicrobial therapy and emergent endovascular treatment. The clinical suspicion of acute infective endocarditis was confirmed by transesophageal echocardiography, demonstrating a large vegetation on the mitral valve associated with severe valvular regurgitation. Abdominal ultrasound was normal with no hepatic, renal, or spleen abscess. Serial blood cultures and thrombus culture, obtained in the vascular procedure, identified non-toxigenic C. diphtheriae, with antibiotic therapy adjustment to monotherapy with ampicillin. Since the patient had a severe septic shock with sustained fever, despite antimicrobial therapy, urgent cardiac surgical intervention was planned. Anatomical findings were compatible with an aggressive endocarditis, requiring mitral valve replacement for a biological prosthesis. During the postoperative period, despite an initial clinical recovery and successfully weaning from mechanical ventilation, the patient presented with a recrudescent daily fever. Computed tomography of the abdomen revealed a hypoattenuating and extensive splenic lesion suggestive of abscess. After sonographically guided bridging percutaneous catheter drainage, surgical splenectomy was performed. Despite left limb revascularization, a forefoot amputation was required due to gangrene. The patient had a good clinical recovery, fulfilling 4-weeks of antimicrobial treatment.
Despite the effectiveness of toxoid-based vaccines, recent global outbreaks of invasive C. diphtheriae infectious related to non-toxigenic strains have been described. These infectious could be highly invasive as demonstrated in this case. Interdisciplinary work with an institutional "endocarditis team" is essential to achieve favorable clinical outcomes in such defiant scenarios.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Vulgarizado em 1961 nos Estados Unidos da América (EUA), o conceito de ‘big science’ refere-se à investigação científica em grande escala, com orçamentos importantes, equipas numerosas, instrumentos ...e laboratórios de grandes dimensões, com produção de uma enorme quantidade de dados. Por meio de revisão bibliográfica e análise documental, analisa-se o Programme for International Student Assessment (PISA), destacando características que apresentam similaridades com o conceito de ‘big science’. Os resultados encontrados apontam que o PISA pode ser considerado o primeiro programa no campo das ciências sociais e humanas que se insere nesta forma de fazer ciência
Chronic kidney disease is commonly found in patients with aortic stenosis (AS) undergoing transcatheter aortic valve replacement (TAVR) and has marked impact in their prognosis. It has been shown ...however that TAVR may improve renal function by alleviating the hemodynamic barrier imposed by AS. Nevertheless, the predictors of and clinical consequences of renal function improvement are not well established. Our aim was to assess the predictors of improvement of renal function after TAVR.
The present work is an analysis of the Brazilian Registry of TAVR, a national non-randomized prospective study with 22 Brazilian centers. Patients with baseline renal dysfunction (estimated glomerular filtration rate eGFR < 60mL/min/1.73m2) were stratified according to renal function after TAVR: increase >10% in eGFR were classified as TAVR induced renal function improvement (TIRFI); decrease > 10% in eGFR were classified as acute kidney injury (AKI) and stable renal function (neither criteria).
A total of 819 consecutive patients with symptomatic severe AS were included. Of these, baseline renal dysfunction (estimated glomerular filtration rate eGFR < 60mL/min/1.73m2) was present in 577 (70%) patients. Considering variance in renal function between baseline and at discharge after TAVR procedure, TIRFI was seen in 197 (34.1%) patients, AKI in 203 (35.2%), and stable renal function in 177 (30.7%). The independent predictors of TIRFI were: absence of coronary artery disease (OR: 0.69; 95% CI 0.48-0.98; P = 0.039) and lower baseline eGFR (OR: 0.98; 95% CI 0.97-1.00; P = 0.039). There was no significant difference in 30-day and 1-year all-cause mortality between patients with stable renal function or TIRFI. Nonetheless, individuals that had AKI after TAVR presented higher mortality compared with TIRFI and stable renal function groups (29.3% vs. 15.4% vs. 9.5%, respectively; p < 0.001).
TIRFI was frequently found among baseline impaired renal function individuals but was not associated with improved 1-year outcomes.
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The diagnostic ultrasound-guided high mechanical index impulses during an intravenous microbubble infusion (sonothrombolysis) improve myocardial perfusion in acute ST segment elevation myocardial ...infarction, but its effect on left ventricular diastolic dysfunction (DD), left atrial (LA) mechanics and remodeling is unknown. We assessed the effect of sonothrombolysis on DD grade and LA mechanics.
One hundred patients (59 ± 10 years; 34% women) were randomized to receive either high mechanical index impulses plus percutaneous coronary intervention (PCI) (therapy group) or PCI only (control group) (n = 50 in each group). Diastolic dysfunction grade and LA mechanics were assessed immediately before and after PCI and at 48 to 72 hours, 1 month, and 6 months of follow-up. Diastolic dysfunction grades were classified as grades I, II, and III. The LA mechanics was obtained by two-dimensional speckle-tracking echocardiography-derived global longitudinal strain (GLS).
As follow-up time progressed, increased DD grade was observed more frequently in the control group than in the therapy group at 1 month and 6 months of follow-up (all P < .05). The LA-GLS values were incrementally higher in the therapy group when compared with the control group at 48 to 72 hours, 24.0% ± 7.3% in the therapy group versus 19.6% ± 7.2% in the control group, P = .005; at 1 month, 25.3% ± 6.3% in the therapy group versus 21.5% ± 8.3% in the control group, P = .020; and at 6 months, 26.2% ± 8.7% in the therapy group versus 21.6% ± 8.5% in the control group, P = .015. The therapy group was less likely to experience LA remodeling (odds ratio, 2.91 1.10-7.73; P = .03). LA-GLS was the sole predictor of LA remodeling (odds ratio, 0.79 0.67-0.94; P = .006).
Sonothrombolysis is associated with better DD grade and LA mechanics, reducing LA remodeling.
Abstract
Aims
Left ventricular remodelling occurs during the chronic course of aortic regurgitation (AR) and aortic stenosis (AS), leading to myocardial hypertrophy and fibrosis. Several studies have ...shown that extracellular volume fraction (ECV) and indexed extracellular volume (iECV) are important surrogate markers of diffuse myocardial fibrosis (MF). Postoperative data on these cardiovascular magnetic resonance (CMR) extracellular expansion parameters for either AS or AR are scarce. This study aimed to demonstrate the postoperative changes that occur in diffuse MF, and the influence of preoperative MF on the reversal of LV remodelling, in patients with AR or AS.
Methods and results
Patients with severe AR or AS and indications for surgery were prospectively enrolled. Patients underwent pre- and postoperative CMR, and ECV and iECV were quantified. Data from 99 patients were analysed (32 with AR and 67 with AS). After surgery, the left ventricle mass index decreased in both groups (AR: 110 vs. 91 g/m2; AS: 86 vs. 68 g/m2, both P < 0.001). The late gadolinium enhancement fraction (AR: preoperative 1.9% vs. postoperative 1.7%, P = 0.575; AS: preoperative 2.4% vs. postoperative 2.4%, P = 0.615) and late gadolinium enhancement mass (AR: preoperative 3.8 g vs. postoperative 2.5 g, P = 0.635; AS: preoperative 3.4 g vs. postoperative 3.5 g, P = 0.575) remained stable in both groups. Preoperative iECV and ECV were greater in the AR group (iECV: 30 mL/m2 vs. 22 mL/m2, P = 0.001; ECV: 28.4% vs. 27.2%, P = 0.048). Indexed extracellular volume decreased after surgery in both groups (AR: 30–26.5 mL/m2, AS: 22–18.2 mL/m2, both P < 0.001); it was still greater in the AR group (AR: 26.5 mL/m2 vs. AS: 18.2 mL/m2, P < 0.001). Postoperative ECV remained stable in the AR group (preoperative 28.4% vs. postoperative 29.9%; P = 0.617) and increased in the AS group (preoperative 27.2% vs. postoperative 28.6%; P = 0.033).
Conclusion
Patients with both AR or AS presented reduction in iECV after surgery, unfolding the reversible nature of diffuse MF. In contrast to patients with AS, those with AR developed postoperative iECV regression with stable ECV, suggesting a balanced reduction in both intracellular and extracellular myocardial components.
Graphical Abstract
Graphical Abstract
Diffuse myocardial fibrosis measures and changes in ECV and iECV. Panels A, B, and C demonstrate automatic native T1, post-contrast T1, and extracellular volume (ECV) measures, respectively, in the postoperative cardiovascular magnetic resonance of a patient with severe aortic stenosis (Global ECV with LGE = 26.1%; iECV = 17.4 mL/m2). Graphics D and E show comparisons between the pre- and postoperative measures of the global ECV with late gadolinium enhancement (LGE) and the indexed extracellular volume (iECV), respectively, in aortic valvular heart diseases. Solid horizontal lines indicate median values; boxes indicate p25 and p75; and vertical lines indicate the highest and lowest values. P values indicate differences between measures (significant if <0.05). NS, non-significant.
The long-term evolution of rivers draining westward from Brazilian Great escarpment remain unclear and one of the main questions is how western draining rivers organized and defined their modern ...courses. In this study, we evaluated how the Piraí Depression (PD) evolved and how rivers draining the PD interior defined their valleys and became an important contributing area for the Paraná River catchment. We used three sets of data: (1) topographical metrics (ks(n), knickpoints, local relief, χ-index values, Gilbert metrics, Swath Profiles and Seppômen Maps); (2) relief and river morphology (elbows and low-divides) from remote sensing derived data; and (3) sedimentologic analysis from a drainage capture previously identified with vibro-corer drilling. Ks(n), local relief and χ indices, and morphological evidence, point to an ongoing process of drainage rearrangement all over PD as it has been continuously eroded by Tibagi, Cinzas, Itararé and, mainly the Atlantic draining rivers from the Ribeira do Iguape River System. Morphometric, morphological and sedimentologic data imply long-lasting recurrence of captures and divide migration. The oldest capture evidence in the study area corresponds to the incision of the Iapó River which created the Guartelá Canyon. At least three generations of captures followed, and the younger generation is exemplified by the Maracanã-Jotuba capture as shown by the fieldwork data and described sedimentary facies. The field-documented underground capture illustrates the progressive abandonment and valley filling of the Maracanã River and capture by Jotuba river. Headward erosion and groundwater sapping are crucial for drainage (re)arrangements. In the PD drainage transition from endorheic to exorheic system was a direct result of captures. Atlantic rivers have greater erosion power and also migrate westward capturing areas from Paraná-La Plata which does not prevent drainage rearrangements to take place between westward-draining rivers.
•The Piraí Depression have been dismantled by headward erosion.•Endorheic to exorheic drainage transition involved captures, expanding the Parana- La Plata system.•Underground processes are key to captures in high plateaus and low relief areas.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPUK, ZAGLJ, ZRSKP
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