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This study examined the effect of coach-initiated motivational climate and parental support on intrinsic motivation, enjoyment of sport participation, subjective vitality, sport-related violence, and academic achievement of youth soccer players. The second purpose was to examine if intrinsic motivation mediates the impact of coach-initiated climate and parental support on the above endogenous variables. Two measurements Time 1 (T1) and Time 2 (T2) were conducted. In T1, 494 young soccer male athletes completed surveys of coach-created motivational climate, parental praise and understanding, intrinsic motivation, sport-related violence, vitality, sport enjoyment and Grade Point Average (GPA). After five months, 188 of those soccer athletes responded again to the same surveys (T2). In both measurements the findings suggest that perceived coach-initiated empowering climate and parental praise and understanding have indirect effects on sport-related violence, GPA, vitality and sport enjoyment through intrinsic motivation in sport.

The integration of renewable rnergy sources (RESs) into the power grid involves operational challenges due to the inherent RES energy-production variability. Imbalances between actual power generation and scheduled production can lead to grid instability and revenue loss for RES operators and aggregators. To address this risk, in this paper, we introduce a mutually beneficial bilateral trading scheme between a RES and a DR aggregator to internally offset real-time energy imbalances before resorting to the flexibility market. We consider that the DR aggregator manages the energy demand of users, characterized by uncertainty in their participation in DR events and thus the actual provision of flexibility, subject to their offered monetary incentives. Given that the RES aggregator faces penalties according to dual pricing for positive or negative imbalances, we develop an optimization framework to achieve the required flexibility while addressing the trade-off between maximizing the profit of the RES and DR aggregators and appropriately incentivizing the users. By using appropriate parameterization of the solution, the achievable revenue for the imbalance offsetting can be shared between the RES and the DR aggregators while keeping users satisfied. Our analysis highlights the interdependencies of the demand–production energy imbalance on user characteristics and the RES and DR aggregator profits. Based on our results, we show that a win–win outcome (for the RES and DR aggregators and the users) is possible for a wide range of cases, and we provide guidelines so that such bilateral agreements between RES and DR aggregators could emerge in practical settings.

Reputation systems are an important means to facilitate trustworthy interactions between on-and off-chain services and users. However, contemporary reputation systems are typically dependent on a trusted central authority to preserve privacy of raters or on adding noise into the user feedback. Moreover, the accuracy of reputation values relies on the integrity of user feedback or input; this feedback should not be tampered with or misused for other purposes. This paper presents blockchain-based reputation system named REPUTABLE (A Decentralized Reputation System for blockchain-based Ecosystems), which computes the reputation of service providers and external services within a blockchain ecosystem through decentralized on-chain and off-chain implementation. Specifically, REPUTABLE not only ensures privacy, but also reliability, integrity and accuracy of reputation values, while incurring minimal overhead. It also enables performing certain data or statistical analytics functions on user feedback, whilst preserving security, privacy, accountability and unlinkability of participants and their feedback. We present a proof-of-concept implementation and a demonstration of the REPUTABLE system. Finally, by means of formal and empirical evaluation, we show the effectiveness of our proposed system to preserve the anonymity of user feedback and the high performance of its blockchain-based implementation.

This paper analyzes the effects of including collective action clauses (CACs) and enhanced CACs in international (nondomestic law-governed) sovereign bonds on sovereigns’ borrowing costs, using secondary-market bond yield spreads. Our findings indicate that inclusion of enhanced CACs, introduced in August 2014, is associated with lower borrowing costs for both noninvestment-grade and investment-grade issuers. These results suggest that market participants do not associate the use of CACs and enhanced CACs with borrowers’ moral hazard, but instead consider their implied benefits of an orderly and efficient debt resolution process in case of restructuring.

Colchicine’s medical evolution is historically bound to the Mediterranean basin, since remarkable researchers from this region underscored its valuable properties. With the passing of years colchicine became an essential pharmaceutical substance for the treatment of rheumatologic and cardiovascular diseases. In light of recent findings, the therapeutic value of colchicine has grown. In clinical practice, colchicine remains underutilized in view of its proven efficacy and safety. Its complex pharmacokinetics and multifaceted anti-inflammatory role remain under investigation. The current review addresses the safe administration of colchicine in view of key drug to drug interactions. Finally, we are briefly presenting colchicine’s future potential applications.

Soil physical and chemical properties can be seriously affected by forest operations. There is a knowledge gap on this topic for oak ecosystems, which can play a significant role in the context of multiple-use forestry. The main objective of this study was to analyse forest floor and topsoil changes (0–10 cm) two years after the application of small-scale thinning (50% reduction of basal area) and clear-cut operations using mules to carry harvested material in a Northern Greece oak (Quercus frainetto Ten)ecosystem. The total amount of forest floor (O1+O2 horizons) was reduced by 37.8% in the thinned and 30.8% in the clear-cut plots compared to control plots. These large reductions are mainly due to reduction in the O2 horizon in the treated plots. Decomposition was reduced in the treated plots, possibly due to the new drier conditions. Treatments increased the soil pH but not to a significant extent. No evidence of erosion was found in the experimental plots due to the protective function of the forest floor and the use of designated mule trails. The areal extent of soil compaction was limited to only 3% of the total area mainly due to the careful planning and implementation of animal skidding. Small differences in C (%) and Ν (%) were found among control, thinned and clear-cut plots. The limiting growth factors in Mediterranean oak ecosystems are soil depth and the seasonal change of soil moisture, especially during the summer dry period. More research on the definition of the optimum thinning degree and extraction systems in similar ecosystems will be important to satisfy the need to improve soil characteristics.

This paper examines the causes, process, and outcome of Belize’s 2016–17 sovereign debt restructuring – its third episode in last 10 years. As was the case in the earlier two restructurings, in 2006–07 and in 2012–13, the 2016–17 debt restructuring was executed through collaborative engagement with creditors outside an IMF-supported program. While providing liquidity relief and partially addressing long-term debt sustainability concerns, the restructuring will need to be underpinned by ambitious fiscal consolidation and growth-enhancing structural reforms to secure durable gains and avoid future debt distress situations.

Background. Computed tomography (CT) and magnetic resonance imaging (MRI) are used for the identification of an adrenal neoplasm. Traditionally, the adrenal gland radiological size (RS) is underestimated by any preoperative imaging compared to the actual histological size (HS). The objective of the study was to investigate whether recent and more sophisticated imaging techniques can more accurately predict adrenal tumors’ size. Material and methods. We retrospectively analyzed 129 patients (86 females, 67%) with mean age 54.2 years (median: 56; range: 6 – 82), who underwent adrenalectomy (1 bilateral adrenalectomy) during the period 11/2016 to 2/2019. The 130 adrenal tumors were divided according to their RS in: A, ≤ 3 cm, B, > 3 cm and ≤ 6 cm, C, > 6 cm. Agreement between RS and HS was evaluated by the intraclass correlation coefficient (ICC). Results. In the total population, RS underestimated HS by 34% using CT or either imaging with good agreement; 28% using MRI with fair agreement. Only for RS 3 – 6cm CT, MRI or either method underestimated HS by 35% with fair agreement; for RS > 6 cm underestimation was 15% using CT, or 6% using either imaging with fair agreement. Conclusions. In defiance of the technological progress in imaging modalities, the present study confirmed previous findings that adrenal imaging by CT or MRI, cannot predict accurately the real size of adrenal tumors. In case of an adrenal incidentaloma this disagreement has a major impact not only on achieving an effective decision- making process favoring a conservative treatment or a surgical excision, but also on deciding when surgery is the option of the appropriate approach by open or laparoscopic adrenalectomy.

Abstract Background Cognitive dysfunction syndrome (CDS) is a common progressive neurodegenerative disease that is poorly defined. Specific multitargeted protocols do not exist for setting the diagnosis and the prognosis of the syndrome. Hypothesis/Objectives To quantify Aβ42 and Aβ40 peptides in blood and cerebrospinal fluid (CSF) and to investigate their contribution to CCDS. Animals A total of 61 dogs from a hospital population. Methods Case‐control study. Six young (YG: 0‐4 years old), 8 middle‐aged (4‐8 years old), 17 cognitively unimpaired and aged (CU: 8‐20 years old), and 30 cognitively impaired and aged (CI: 8‐17 years). From the CI group, 10 dogs exhibited mild impairment (CI‐MCI) and 20 exhibited severe impairment (CI‐SCI). Cognitive status was assessed using a validated owner‐based questionnaire. Direct and indirect Aβ markers were determined in plasma fractions (total‐TP, free‐FP, bound to plasma components‐CP) and CSF using commercial ELISA assays (AΒtest, Araclon Biotech). Results TPAβ42/40 facilitated discrimination between CI‐MCI and CU aged dogs with area under curve ≥ 0.79. CSFAβ42 levels were higher (P = .09) in CU (1.25 ± 0.28 ng/mL) than in MCI (1.04 ± 0.32 ng/mL) dogs. CSF Aβ42 levels were correlated with the CP fragment (CPAβ40: P = .02, CPAβ42: P = .02). CPAβ42 was higher in the CI‐MCI (23.03 ± 11.79 pg/μL) group compared to the other aged dogs (CU: 10.42 ± 7.18 pg/μL, P = .02, SCI: 11.40 ± 12.98 pg/μL, P = .26). Conclusion and Clinical Importance The Aβ should be determined in all of the 3 plasma fractions (TP, FP, CP). In the clinical approach, TPAβ42/40 could be used as an efficient preselection tool for the aged canine population targeting dogs with mild cognitive impairment.

Introduction. The association of autoimmune thyroid disease (AITD) with diabetes mellitus type-1 (DM1) has been previously documented. However, limited data exist regarding the association of AITD and diabetes mellitus type-2 (DM2). The objective of the study was to expose the role of AITD on DM2 and the impact of AITD in euthyroid patients with pre-diabetes. Euthyroid prediabetic patients were defined by impaired fasting glucose and/or glucose intolerance. Material and methods. We assessed static and dynamic insulin resistance (IRI) and insulin secretion indices (ISI), and the disposition index (DI). Results. Out of 166 patients studied, 31.9% had AITD; impaired fasting glucose (IFG) prevalence was the same with non-AITD patients. In contrast, impaired glucose tolerance (IGT) was less prevalent in AITD compared to non-AITD patients (9.4% versus 28.3%, p=0.008). IRI did not differ between the two groups. The dynamic ISI, 1st phase and 2nd phase insulin release, and the DI showed a worse insulin secretion in non-AITD compared to AITD patients (0.54 versus 0.45, p=0.029; 1029.3 versus 864.3, p=0.033; 354.8 versus 286.5, p=0.035; 0.09 versus 0.07, p=0.02, respectively). On the other hand, hsCRP was higher in AITD versus non-AITD individuals (p=0.008). Conclusions. Although individuals with pre-diabetes and AITD presented with higher levels of low-grade inflammation, their dynamic ISI and the DI, were less impaired.

Transcatheter aortic valve implantation (TAVI) led to the foundation of the subspecialty of structural heart interventions and created an emerging area of clinical and technical issues. Soon after TAVI introduction into clinical practice, boundaries were expanded with utilization of valve-in-valve (V-i-V) techniques. V-i-V comprised a diverse subset of patients including TAVI within TAVI, TAVI within a degenerated surgically implanted bioprosthesis, or even TAVI-in-TAVI-in-surgical bioprosthesis. In the present review, we summarize the available literature and present initial experience on the field in Greece.

Pulmonary vein isolation (PVI) is the cornerstone in atrial fibrillation (AF) ablation; yet, the role of arrhythmogenic superior vena cava (SVC) is increasingly recognized and different ablation strategies have been employed in this context. SVC can act as a trigger or perpetuator of AF, and its significance might be more pronounced in patients undergoing repeated ablation. Several cohorts have examined efficacy, safety and feasibility of SVC isolation (SVCI) among AF patients. The majority of these studies explored as-needed SVCI during index PVI, and only a minority of them included repeated ablation subjects and non-radiofrequency energy sources. Studies of heterogeneous design and intent have explored both empiric and as-needed SVCI on top of PVI and reported inconclusive results. These studies have largely failed to demonstrate any clinical benefit in terms of arrhythmia recurrence, although safety and feasibility are undisputable. Mixed population demographics, small number of enrollees and short follow-up are the main limitations. Procedural and safety data are comparable between empiric SVCI and as-needed SVCI, and some studies suggested that empiric SVCI might be associated with reduced AF recurrences in paroxysmal AF patients. Currently, no study has compared different ablation energy sources in the setting of SVCI, and no randomized study has addressed as-needed SVCI on top of PVI. Furthermore, data regarding cryoablation are still in their infancy, and regarding SVCI in patients with cardiac devices more safety and feasibility data are needed. PVI non-responders, patients undergoing repeated ablation and patients with long SVC sleeves could be potential candidates for SVCI, especially via an empiric approach. Although many technical aspects remain unsettled, the major question to answer is which clinical phenotype of AF patients might benefit from SVCI?

Polymerase chain reaction (PCR) is the most common method used for nucleic acid (DNA) amplification. The development of PCR-performing microfluidic reactors (μPCRs) has been of major importance, due to their crucial role in pathogen detection applications in medical diagnostics. Closed loop (CL) is an advantageous type of μPCR, which uses a circular microchannel, thus allowing the DNA sample to pass consecutively through the different temperature zones, in order to accomplish a PCR cycle. CL μPCR offers the main advantages of the traditional continuous-flow μPCR, eliminating at the same time most of the disadvantages associated with the long serpentine microchannel. In this work, the performance of three different CL μPCRs designed for fabrication on a printed circuit board (PCB) was evaluated by a computational study in terms of the residence time in each thermal zone. A 3D heat transfer model was used to calculate the temperature distribution in the microreactor, and the residence times were extracted by this distribution. The results of the computational study suggest that for the best-performing microreactor design, a PCR of 30 cycles can be achieved in less than 3 min. Subsequently, a PCB chip was fabricated based on the design that performed best in the computational study. PCB constitutes a great substrate as it allows for integrated microheaters inside the chip, permitting at the same time low-cost, reliable, reproducible, and mass-amenable fabrication. The fabricated chip, which, at the time of this writing, is the first CL μPCR chip fabricated on a PCB, was tested by measuring the temperatures on its surface with a thermal camera. These results were then compared with the ones of the computational study, in order to evaluate the reliability of the latter. The comparison of the calculated temperatures with the measured values verifies the accuracy of the developed model of the microreactor. As a result of that, a total power consumption of 1.521 W was experimentally measured, only ~7.3% larger than the one calculated (1.417 W). Full validation of the realized CL μPCR chip will be demonstrated in future work.

Objective: We aim to investigate whether EEG dynamics differ in adults with ASD (Autism Spectrum Disorders), ADHD (attention-deficit/hyperactivity disorder), compared with healthy subjects during the performance of an innovative cognitive task: Aristotle's valid and invalid syllogisms. We follow the Neuroanatomical differences type of criterion in assessing the results of our study in supporting or not the dual-process theory of Kahneman, 2011) (Systems I & II of thinking). Method: We recorded EEGs from 14 scalp electrodes in 30 adults with ADHD, 30 with ASD and 24 healthy, normal subjects. The subjects were exposed in a set of innovative cognitive tasks (inducing varying cognitive loads), the Aristotle's four types of syllogism mentioned above. The multiscale entropy (MSE), a nonlinear information-theoretic measure or tool was computed to extract features that quantify the complexity of the EEG. Results: The dynamics of the curves of the grand average of MSE values of the ADHD and ASD participants was significantly in higher levels for the majority of time scales, than the healthy subjects over a number of brain regions (electrodes locations), during the performance of both valid and invalid types of syllogism. This result is seemingly not in accordance of the broadly accepted ‘theory’ of complexity loss in ‘pathological’ subjects, but actually this is not the case as explained in the text. ADHD subjects are engaged in System II of thinking, for both Valid and Invalid syllogism, ASD and Control in System I for valid and invalid syllogism, respectively. A surprising and ‘provocative’ result of this paper, as shown in the next sections, is that the Complexity-variability of ASD and ADHD subjects, when they face Aristotle's types of syllogisms, is higher than that of the control subjects. An explanation is suggested as described in the text. Also, in the case of invalid type of Aristotelian syllogisms, the linguistic and visuo-spatial systems are both engaged ONLY in the temporal and occipital regions of the brain, respectively, of ADHD subjects. In the case of valid type, both above systems are engaged in the temporal and occipital regions of the brain, respectively, of both ASD and ADHD subjects, while in the control subjects only the visuo-spatial type is engaged (Goel et al., 2000; Knauff, 2007). Conclusion: Based on the results of the analysis described in this work, the differences in the EEG complexity between the three groups of participants lead to the conclusion that cortical information processing is changed in ASD and ADHD adults, therefore their level of cortical activation may be insufficient to meet the peculiar cognitive demand of Aristotle's reasoning. Significance: The present paper suggest that MSE, is a powerful and efficient nonlinear measure in detecting neural dysfunctions in adults with ASD and ADHD characteristics, when they are called on to perform in a very demanding as well as innovative set of cognitive tasks, that can be considered as a new diagnostic ‘benchmark’ in helping detecting more effectively such type of disorders. A linear measure alone, as the typical PSD, is not capable in making such a distinction. The work contributes in shedding light on the neural mechanisms of syllogism/reasoning of Aristotelian type, as well as toward understanding how humans reason logically and why ‘pathological’ subjects deviate from the norms of formal logic.

Background: Economic crisis poses an immense threat to public health worldwide and has been linked to cardiovascular morbidity and mortality. Greece is facing a distinctive recession over the recent years. However, the exact impact on coronary artery disease (CAD) burden has not been adequately addressed. Methods: Demographic, clinical, and angiographic data of 3895 hospitalized patients were retrospectively studied. Patients were classified into two groups: those before crisis (2006–2007, n = 1228) and those during crisis (2011–2015, n = 2667). Results: All data before and during crisis were compared. During crisis, patients presented with less acute coronary syndrome (ACS – 45.5% vs. 39.9%, p

Introduction. Conflicting findings have been published regarding the pressure wave reflection and the arterial stiffness in young women with polycystic ovary syndrome (PCOS) as opposed to the overt ab initio presence of endothelial dysfunction, which can be reversed six months after metformin administration. The aim of this study was to investigate wave reflections in women with PCOS and to evaluate the effect of metformin treatment. Material and methods. Sixty-four young women, 35 with PCOS (P) (20 lean(L), PL; 15 overweight/ obese (OWB), POWB) and 29 controls (18 CL;11 COWB) were studied. Wave reflection was assessed by the Augmentation Index (AIx) as central augmentation pressure-to-pulse height ratio corrected for heart rate (HR) 75 bpm (AIX@75) or without HR correction AIx and the central augmentation time index (Tr). The endothelial function was evaluated biochemically by plasma endothelin 1(ET-1) levels. The metabolic and hormonal profile and a dvanced glycated end-products (AGEs) levels were also assessed. Metformin (1700 mg/daily) was administered for six months in 20 (9 lean, 11 obese) women with PCOS and the measurements were repeated. Results. All subgroups had comparable age. Wave reflection indices did not differ between PCOS and controls. AIx@75 significantly improved post-metformin treatment in POWB (p=0.046). AGE levels differed between PCOS women groups and controls (p

Introduction. Arterial variations may cause significant complications during diagnostic and interventional procedures. The objective of the study. Our study examined 73 donated cadavers in the National and Kapodistrian University of Athens, in an effort to unearth possible artery alternations. Material and methods. The major branches of the abdominal aorta, the arteries of the limps and the neck were inquired. Results. In 58.9% of the cadavers no arterial variation was found, whereas one, two and three alternations at the same cadaver were observed in 21.9%, 12.3% and 6.8% respectively. The most common anatomical variations were noted in the vascular branching of the celiac trunk found in 24.7% of the cadavers. Conclusions. There was no statistically significant difference between the two genders concerning the frequency of the observed arterial variations (p

This paper documents the two debt restructurings that Grenada undertook in 2004–06 and 2013–15. Both restructurings emerged as a consequence of weak fiscal and debt situations, which became unsustainable soon after external shocks hit the island economy. The two restructurings provided liquidity relief, with the second one involving a principal haircut. However, the first restructuring was not able to secure long-term debt sustainability. Grenada’s restructuring experience shows the importance of (1) establishing appropriate debt restructuring objectives; (2) committing to policy reforms and maintaining ownership of the restructuring goals; and (3) engaging closely and having clear communications with creditors.

Purpose. This study aimed to quantify the deviation of an arterial pulse (pressure wave) from the „golden“ or „divine“ pulse, defined according to the golden ratio φ (phi), and to investigate whether the extent of this deviation is related to the function of autonomic nervous system (ANS) as assessed by 24-hr heart rate variability (HRV). Methods. Seventy-two healthy subjects underwent 24-hr continuous monitoring of ECG. Applanation tonometry of the radial artery and pulse wave analysis of peripheral and central (mathematically derived) aortic pressure waveforms were performed in all subjects. Time- and frequency domain indices of HRV were computed together with nonlinear dynamic parameters. Two novel indices were computed primarily based on pressure (systolic and diastolic pressure; mmHg) and time (ejection and diastolic durations-intervals; msec) values extracted from the recorded pressure waves. Results. The new phenotypic, geometrical biomarkers based on the golden ratio (φ) were associated withHRV indices and especially with those computed at the frequency domain. These associations were independent from age, gender, body mass index, mean arterial pressure, pulse pressure and mean 24-hr heart rate. Conclusion. The new proposed geometrical analysis of the arterial pulse reflects/characterizes specific 24-hr HRV features and is independently related with ANS function. Although the potential pathophysiological, underlying mechanisms of this association can be hardly explained by this study, the application of the golden ratio φ for the analysis of the arterial pulse merits further investigation and may open a new window for the evaluation of cardiovascular risk.

Analysis of classical cerebrospinal fluid biomarkers, especially when incorporated in a classification/diagnostic system such as the AT(N), may offer a significant diagnostic tool allowing correct identification of Alzheimer’s disease during life. We describe four patients with more or less atypical or mixed clinical presentation, in which the classical cerebrospinal fluid biomarkers amyloid peptide with 42 and 40 amino acids (Aβ42 and Aβ40, respectively), phospho-tau (τP-181) and total tau (τΤ) were measured. Despite the unusual clinical presentation, the biomarker profile was compatible with Alzheimer’s disease in all four patients. The measurement of classical biomarkers in the cerebrospinal fluid may be a useful tool in identifying the biochemical fingerprints of Alzheimer’s disease, especially currently, due to the recent approval of the first disease-modifying treatment, allowing not only typical but also atypical cases to be enrolled in trials of such treatments.

The prevalence of atrial fibrillation (AF) is bound to increase globally in the following years, affecting the quality of life of millions of people, increasing mortality and morbidity, and beleaguering health care systems. Increasingly effective therapeutic options against AF are the constantly evolving electroanatomic substrate mapping systems of the left atrium (LA) and ablation catheter technologies. Yet, a prerequisite for better long-term success rates is the understanding of AF pathogenesis and maintenance. LA electrical and anatomical remodeling remains in the epicenter of current research for novel diagnostic and treatment modalities. On a molecular level, electrical remodeling lies on impaired calcium handling, enhanced inwardly rectifying potassium currents, and gap junction perturbations. In addition, a wide array of profibrotic stimuli activates fibroblast to an increased extracellular matrix turnover via various intermediaries. Concomitant dysregulation of the autonomic nervous system and the humoral function of increased epicardial adipose tissue (EAT) are established mediators in the pathophysiology of AF. Local atrial lymphomononuclear cells infiltrate and increased inflammasome activity accelerate and perpetuate arrhythmia substrate. Finally, impaired intracellular protein metabolism, excessive oxidative stress, and mitochondrial dysfunction deplete atrial cardiomyocyte ATP and promote arrhythmogenesis. These overlapping cellular and molecular alterations hinder us from distinguishing the cause from the effect in AF pathogenesis. Yet, a plethora of therapeutic modalities target these molecular perturbations and hold promise in combating the AF burden. Namely, atrial selective ion channel inhibitors, AF gene therapy, anti-fibrotic agents, AF drug repurposing, immunomodulators, and indirect cardiac neuromodulation are discussed here.

This paper examines the causes, processes, and outcomes of the two Belize sovereign debt restructurings in 2006–07 and in 2012–13, which occurred outside an IMF-supported program. It finds that the motivation for the two debt restructurings differed, as the former was driven by external liquidity concerns while the latter was motivated by a substantial increase in the coupon rates and future fiscal solvency concerns. Despite differential treatment between residents and non-residents, both 2006–07 and 2012–13 debt exchanges were executed through collaborative engagement, due in part to the existence of a broad-based creditor committee and the authorities’ effective communication strategy. However, while providing temporary liquidity relief, neither of the debt restructurings properly addressed long-term debt sustainability concerns. Going forward, the success of the 2012–13 debt restructuring will still depend on the country’s ability to strengthen fiscal efforts and the public debt management framework.

Aim: The investigation of the association between total arterial compliance (CT)—estimated by a novel technique—with left ventricular mass (LVM) and hypertrophy (LVH). Our hypothesis was that CT may be better related to LVM compared to the gold-standard regional aortic stiffness. Within the frame of the ongoing cross-sectional study “SAFAR,” 226 subjects with established hypertension or with suspected hypertension underwent blood pressure (BP) assessment, carotid-to-femoral pulse wave velocity (cf-PWV), and echocardiographic measurement of LVM. LVM index (LVMI) was calculated by the ratio of LVM to body surface area. CT was estimated by a previously proposed and validated formula: CT = 36.7 /cf-PWV2 [ml/mmHg]. LVMI was related to age (r = 0.207, p = 0.002), systolic BP (r = 0.248, p < 0.001), diastolic BP (r = 0.139, p = 0.04), mean BP (r = 0.212, p = 0.002), pulse pressure (r = 0.212, p = 0.002), heart rate (r = −0.172, p = 0.011), cf-PWV (r = 0.268, p < 0.001), and CT (r = −0.317, p < 0.001). The highest correlation was observed for CT that was significantly stronger than the respective correlation of cf-PWV (p < 0.001). In multivariate analysis, CT was a stronger determinant, compared to cf-PWV, of LVMI and LVH. It remains to be further explored whether CT has also a superior prognostic value beyond and above local or regional (segmental) estimates of pulse wave velocity.

Background: Cardiac output (CO) monitoring remains a salient challenge. The state-of-the-art is based on generalized transfer functions and parameter estimations from pooled clinical data, which do not necessarily reflect the state of the cardiovascular system in a patient-specific way. Here, we introduce a patient-specific approach to estimate CO from sequential radial pressure measurements and carotid-to-femoral pulse wave velocity (cf-PWV). We do so by effectively tuning a generalized mathematical model of the cardiovascular system (1). Methods: Initially, the method uses the measured cf-PWV to estimate arterial compliance. We consequently determine aortic flow from beat-to-beat radial pressure measurements based on the assumption of a fairly constant total peripheral resistance (TPR) over several heartbeats (2). Concretely, we developed an algorithm which, starting from an initial flow, employs a gradient-based optimization process (3) to calculate TPR at each beat. This TPR value is subsequently used as input for a new flow approximation. The process is repeated until convergence is reached. To assess the accuracy of the method, we implemented the algorithm on in vivo anonymized data from n=15 subjects (4) and compared the method-derived CO to the measured ones. Results: Our results demonstrated that precise estimates of CO were yielded, with a RMSE of 0.38 L/min (Fig. 1). Small variance in arterial compliance tuning did not show to significantly undermine the accuracy of the CO predictions. Conclusions: The in vivo validation allows us to conclude that our novel method accurately estimates CO in a patient-specific way. Therefore, the technique may potentially be employed for noninvasive CO monitoring in the clinical setting.

During 19th century the term “cardiolith” was widely used to describe a cluster of cardiac entities that could cause sudden death. Blood clots, polypoid growths, microorganisms and inflammation were implicated. Scientists of the era described formations that could enter any heart chamber after having been formed in any portion of the cardiac substance and could provoke a deadly thrombus or embolus. While pathologist and bacteriologist Auguste Sheridan Delépine (1855–1921), was the first who used the term “cardiolith” in his treatise “Description of a cardiolith” in 1890, a series of researchers noted the phenomenon, forming the “School of Cardiolithists”.

We study the co-evolution of the dynamics or co-movement of two electricity markets, the Italian and Greek, by studying the dynamics of their wholesale day-ahead prices, simultaneously in the time-frequency domain. Co-movement is alternatively referred as market integration in financial economics and markets are internationally integrated if the reward for risk is identical regardless the market one trades in. The innovation of this work is the application of wavelet analysis and more specifically the wavelet coherence to estimate the dynamic interaction between these two prices. Our method is compared to other generic econometric tools used in Economics and Finance namely the dynamic correlation and coherence analysis, to study the co-movement of variables of the type related to these two fields. Our study reveals valuable information that we believe will be extremely useful to the authorities as well as other agents participating in these markets to better prepare the national markets towards the European target model, a framework in which the two markets will be coupled.

Brachial cuff blood pressure (BP) is clinically important, but may be an inaccurate substitute for central BP. Many non-invasive devices have been developed that purport to estimate central BP from peripheral artery sites, yet with no standardized guidelines; the accuracy testing of these new devices has not been undertaken in a uniform fashion with comparable protocols. This is an abridged paper describing the recommendations reached by an international task force convened to identify issues that need to be addressed and reach consensus relating to methods for assessing and reporting the accuracy (validation) of central BP devices. The recommendations are endorsed by the Association for Research into Arterial Structure and Physiology (ARTERY) Society, as well as the European Society of Hypertension (ESH) Working Group on Arterial Structure and Function, and the ESH Working Group on Blood Pressure Monitoring and Cardiovascular Variability. Researchers interested in validating central BP monitors should read the full version of the statement.

Background: Chronic systemic inflammatory diseases (CSID) are associated with increased cardiovascular morbidity and mortality. Widening of retinal venular calibers has been independently associated with systemic inflammation and cardiovascular risk in the general population. We aimed to test the hypothesis that retinal vessel calibers are altered in a population with rheumatoid arthritis (RA), systemic lupus erythematosus (SLE) and spondyloarthropathies (SpA) compared to a reference group (RG). Methods: Between 2012 and 2014 digital retinal images were obtained from consecutive individuals and retinal vessel calibers were measured with validated software to determine central retinal arteriolar and venular equivalents. Results: One hundred eighty-eight patients with CSID [(74 RA, 75 SLE, 39 SpA), (70.2% females, mean age 50.4 ± 12.5 years)] and 512 non-CSID individuals [(187 normotensives and 325 hypertensives, 90 of whom untreated; RG), (43.7% females, mean age 52.3 ± 11.7)] were recruited. Logistic regression analysis after adjustment for all factors associated with retinal vessel calibers in univariate analysis (age, sex, body mass index, blood pressure, anti-hypertensive/lipid modifying drugs and disease duration), showed that both arteriolar and venular retinal vessel calibers were comparable between CSID patients and the RG. No significant differences were found regarding retinal vessel calibers between each patient subgroup and the RG. Conclusions: Retinal vessel calibers were not significantly altered in patients with CSID. Well-controlled disease, as indicated by inflammatory indices, may be an explanation of our results suggesting that sufficient control of inflammation could improve microvascular abnormalities in these populations.

Background: Arterial stiffness measured under static conditions reclassifies significantly cardiovascular (CV) risk and associates with organ damage, including narrower retinal arterioles. However, arterial stiffness exhibits diurnal variation, thus single static stiffness recordings do not correspond to the “usual” 24 hr, awake and asleep average arterial stiffness. We aimed to test the hypothesis that ambulatory 24 hr, awake and asleep aortic (a) pulse wave velocity (PWV) associate with retinal vessel calibers, independently of confounders and of static arterial stiffness, in hypertensive individuals free from diabetes and CV disease. Methods: Digital retinal images were obtained (181 individuals, age: 53.9 ± 10.7 years, 55.2% men) and retinal vessel calibers were measured with validated software to determine central retinal arteriolar and venular equivalents (CRAE and CRVE, respectively); ambulatory (24 hr, awake, asleep) and static office aPWV were estimated by Mobilo-O-Graph; and static office carotid-femoral (cf) PWV by SphygmoCor. Results: Regression analysis performed in 320 gradable retinal images showed that, after adjustment for confounders: (i) ambulatory aPWV was significantly associated with narrower retinal arterioles but not with venules; (ii) asleep aPWV had stronger associations with CRAE than awake aPWV; (iii) both ambulatory aPWV and cfPWV were associated mutually independently with narrower retinal arterioles; aPWV introduction in the model of cfPWV, improved model’s R2 (p = 0.012). Similar discriminatory ability of 24 hr aPWV and of cfPWV to detect the presence of retinal arteriolar narrowing was found. Conclusion: Ambulatory aPWV, estimated by an operator-independent method, provides additional information to cfPWV regarding the associations of arterial stiffness with the retinal microcirculation.

In this work we propose a new hybrid model, a combination of the manifold learning Principal Components (PC) technique and the traditional multiple regression (PC-regression), for short and medium-term forecasting of daily, aggregated, day-ahead, electricity system-wide load in the Greek Electricity Market for the period 2004–2014. PC-regression is shown to effectively capture the intraday, intraweek and annual patterns of load. We compare our model with a number of classical statistical approaches (Holt-Winters exponential smoothing of its generalizations Error-Trend-Seasonal, ETS models, the Seasonal Autoregressive Moving Average with exogenous variables, Seasonal Autoregressive Integrated Moving Average with eXogenous (SARIMAX) model as well as with the more sophisticated artificial intelligence models, Artificial Neural Networks (ANN) and Support Vector Machines (SVM). Using a number of criteria for measuring the quality of the generated in-and out-of-sample forecasts, we have concluded that the forecasts of our hybrid model outperforms the ones generated by the other model, with the SARMAX model being the next best performing approach, giving comparable results. Our approach contributes to studies aimed at providing more accurate and reliable load forecasting, prerequisites for an efficient management of modern power systems.

Objectives: To search for: (i) potential differences in the within-subject pulse pressure (PP) day time variability between the brachial artery and aorta; (ii) the presence of substantial day time variation in the aortic-to-brachial (AtB) PP disparity. Background: Brachial blood pressure (BP) variability is a risk factor, but also a source of inaccuracy for the assessment of BP-related cardiovascular risk. PP differs substantially in simultaneous measurements at the brachial artery and the aorta; this is of clinical importance regarding accurate cardiovascular risk assessment and reduction strategies. Whether the brachial and the aortic PP time variability is similar, and whether the AtB PP disparity varies during the day is not known. Methods: In 13 healthy volunteers hourly assessment of brachial and aortic PP was performed (8:00–19:00) under controlled conditions at home. Results: Aortic PP day variability was consistently and significantly lower than brachial PP (assessed by: standard deviation, variance and time rate variation index, p < 0.05 for all). Individual AtB PP difference (brachial – aortic PP, mmHg) varied substantially within all the 13 subjects; a significant variation during the day in the AtB PP amplification (defined as brachial/aortic PP) was evident (p = 0.006). Conclusions: By taking into account both time and arterial space, substantial physiological differences in PP variability between the brachial artery and the aorta were observed. These novel findings suggest that non-invasive 24-h aortic ambulatory BP monitoring is warranted in order to significantly improve CV risk assessment and reduction strategies. This possibility must be tested in future clinical studies.