Opening of Ancillary Service Markets to Distributed Energy Resources: A Review

Electric power systems are moving toward more decentralized models, where energy generation is performed by small and distributed power plants, often from renewables. With the gradual phase out from fossil fuels, however, Distribution Energy Resources (DERs) are expected to take over in the provision of all regulation services required to operate the grid. To this purpose, the opening of national Ancillary Service Markets (ASMs) to DERs is considered an essential passage. In order to allow this transition to happen, current opportunities and barriers to market participation of DERs must be clearly identified. In this work, a comprehensive review is provided of the state-of-the-art of research on DER integration into ASMs. The topic at hand is analyzed from different perspectives. First, the current situation and main trends regarding the reformation processes of national ASMs are analyzed to get a clear picture of the evolutions expected and adjustment required in the future, according to the scientific community. Then, the focus is moved to the strategies to be adopted by aggregators for the effective control and coordination of DERs, exploring the challenges posed by the uncertainties affecting the problem. Coordination schemes between transmission and distribution system operators, and the implications on the grid infrastructure operation and planning, are also investigated. Finally, the review deepens the control capabilities required for DER technologies to perform the needed control actions

The ABCDEF's of Matrix Models for Supersymmetric Chern-Simons Theories

We consider N = 3 supersymmetric Chern-Simons gauge theories with product unitary and orthosymplectic groups and bifundamental and fundamental fields. We study the partition functions on an S^3 by using the Kapustin-Willett-Yaakov matrix model. The saddlepoint equations in a large N limit lead to a constraint that the long range forces between the eigenvalues must cancel; the resulting quiver theories are of affine Dynkin type. We introduce a folding/unfolding trick which lets us, at the level of the large N matrix model, (i) map quivers with orthosymplectic groups to those with unitary groups, and (ii) obtain non-simply laced quivers from the corresponding simply laced quivers using a Z_2 outer automorphism. The brane configurations of the quivers are described in string theory and the folding/unfolding is interpreted as the addition/subtraction of orientifold and orbifold planes. We also relate the U(N) quiver theories to the affine ADE quiver matrix models with a Stieltjes-Wigert type potential, and derive the generalized Seiberg duality in 2 + 1 dimensions from Seiberg duality in 3 + 1 dimensions.Comment: 30 pages, 5 figure

Heterogenous forms of dyslipidemiain women with polycystic ovary syndrome

Forms of dyslipidemia are very common in individuals affected by polycystic ovary syndrome (PCOS), but in addition to plasmatic lipids, it is necessary to evaluate the alterations in the atherogenic lipoproteins (Lp) and apolipoproteins (apo). In our study we measured the concentrations of apoB, Lp(a) and low density lipoproteins (LDL) in 42 patients with PCOS (age: 28 +/- 7 years, body mass index: 27 +/- 5 kg/m-) and 37 healthy women (of the same age and body mass index). Methods: values of Lp(a) >30 mg/dl were considered high, whereas for apoB, values >100 g/l were considered high. Results: the patients with PCOS showed an increase in triglycerides (p=0.0011) and low levels of high density lipoproteins (HDL) (p=0.0131), but the total cholesterol and the LDLs were not significantly different to those of the control group. High levels of Lp(a) were found in 24% of the individuals with PCOS, and a smaller number showed high levels of apoB (14%). This analysis shows that the concentrations of Lp(a) are only correlated to the HDL levels (r =0.378, p= 0.0431). 36% of the patients with PCOS with normal levels of plasmatic lipids show high levels of Lp(a) and apoB, and small and dense LDLs. Conclusions: alterations in the plasmatic lipids are present in 1/3 of the women affected by PCOS. More research is necessary to better understand the mechanisms responsible to reduce the risk of cardiovascular problems in young women with polycystic ovary syndrome

Nerve degeneration in inguinal hernia specimens

BACKGROUND: The histological study of the herniated inguinal area is rare in the literature. This report is focused on the detection of structural changes of the nerves within tissues bordering the inguinal hernia of cadavers. Their physiopathological consequences are hypothesized. MATERIALS AND METHODS: Primary inguinal hernia was diagnosed in 30 fresh cadavers. Tissue specimens from the inguinal region close to and around the hernia opening were excised for histological examination. A control of the data was achieved through tissue samples excised from equivalent sites of the inguinal region in 15 cadavers without hernia. RESULTS: The detected nerves in the inguinal area demonstrated pathological changes such as fibrotic degeneration, atrophy, and fatty dystrophy of the axons. The thickening of the perineural sheath was constantly seen. These findings were consistently present, independent of the hernia type. CONCLUSIONS: The detected nerve alterations lead us to imagine a worsening, or even the cessation, of the nervous impulse to the muscles, leading to atrophy and weakening of the abdominal wall. This could represent one of the multifactorial causes of hernia genesis

fixation free inguinal hernia repair with the 3d dynamic responsive prosthesis proflor features procedural steps and long term results

Abstract Background Static and fixated meshes to repair mobile structures like the groin may seem a procedural incongruence. Inguinal hernia is described as a degenerative disease. Therefore, the objective of disease treatment should be the regeneration of wasted tissue. The fibrotic scar plate, a typical biologic response of conventional static meshes, does not represent tissue regeneration but rather a foreign body reaction. These contrasting aspects seem to be related to high complication rates of inguinal herniorrhaphy. Recent studies concerning the pathophysiology of the groin have led to the development of new concepts for repairing inguinal protrusions. A proprietary designed 3D dynamic responsive implant showing regenerative biologic response is the result of this studies. Materials and methods A cohort of 389 individuals underwent open inguinal hernia repair with the 3D dynamic responsive implant following a specific surgical technique. Thanks to the inherent dynamic properties, all procedures were performed without need for fixation of the 3D prosthesis. Results The outcomes of the dynamic hernia repair procedure were reduced postoperative pain and minimized overall complication rates, also long term. Moreover, no patient discomfort or chronic pain was reported. Conclusions Inguinal hernia repair with the 3D dynamic responsive implant ProFlor seems to represent an effective concept change for the treatment of this widespread degenerative disease. Moving in synchrony with the groin, implanted without need of fixation and acting as a regenerative scaffold, ProFlor™ appears to possess all that is needed for a physiologic and pathogenetical consequent treatment of inguinal protrusions leading to a dramatic lessening of intra- and postoperative complications

Arterial stiffness, endothelial and cognitive function in subjects with type 2 diabetes in accordance with absence or presence of diabetic foot syndrome.

BACKGROUND: Endothelial dysfunction is an early marker of cardiovascular disease so endothelial and arterial stiffness indexes are good indicators of vascular health. We aimed to assess whether the presence of diabetic foot is associated with arterial stiffness and endothelial function impairment. METHODS: We studied 50 subjects with type 2 diabetes mellitus and diabetic foot syndrome (DFS) compared to 50 diabetic subjects without diabetic foot, and 53 patients without diabetes mellitus, by means of the mini mental state examination (MMSE) administered to evaluate cognitive performance. Carotid-femoral pulse wave velocity (PWV) and augmentation index (Aix) were also evaluated by Applanation tonometry (SphygmoCor version 7.1), and the RH-PAT data were digitally analyzed online by Endo-PAT2000 using reactive hyperemia index (RHI) values. RESULTS: In comparison to diabetic subjects without diabetic foot the subjects with diabetic foot had higher mean values of PWV, lower mean values of RHI, and lower mean MMSE. At multinomial logistic regression PWV and RHI were significantly associated with diabetic foot presence, whereas ROC curve analysis had good sensitivity and specificity in arterial PWV and RHI for diabetic foot presence. CONCLUSIONS: Pulse wave velocity and augmentation index, mean RHI values, and mean MMSE were effective indicators of diabetic foot. Future research could address these issues by means of longitudinal studies to evaluate cardiovascular event incidence in relation to arterial stiffness, endothelial and cognitive markers

Feeding the brain: the importance of nutrients for brain functions and health

\u2018We are what we eat\u2019, said the philosopher Feuerbach. In fact, the quality of the food we eat affects our mind as well: the brain, which represents 2% of our body weight, consumes about 20% of the calories we eat each day. Follow a few rules could therefore help to feed properly our brain, so it works to the best of its ability. It is important to know properties of foods especially regarding their aminoacidic composition because aminoacids are components of neurotransmitters, molecules needed for brain transmission and function. It is also possible to choose specific food to prevent or support different diseases that affects nervous system

Mechanical correlates of dyspnea in bronchial asthma.

We hypothesized that dyspnea and its descriptors, that is, chest tightness, inspiratory effort, unrewarded inspiration, and expiratory difficulty in asthma reflect different mechanisms of airflow obstruction and their perception varies with the severity of bronchoconstriction. Eighty-three asthmatics were studied before and after inhalation of methacholine doses decreasing the 1-sec forced expiratory volume by ~15% (mild bronchoconstriction) and ~25% (moderate bronchoconstriction). Symptoms were examined as a function of changes in lung mechanics. Dyspnea increased with the severity of obstruction, mostly because of inspiratory effort and chest tightness. At mild bronchoconstriction, multivariate analysis showed that dyspnea was related to the increase in inspiratory resistance at 5 Hz (R 5) (r (2) = 0.10, P = 0.004), chest tightness to the decrease in maximal flow at 40% of control forced vital capacity, and the increase in R 5 at full lung inflation (r (2) = 0.15, P = 0.006), inspiratory effort to the temporal variability in R 5-19 (r (2) = 0.13, P = 0.003), and unrewarded inspiration to the recovery of R 5 after deep breath (r (2) = 0.07, P = 0.01). At moderate bronchoconstriction, multivariate analysis showed that dyspnea and inspiratory effort were related to the increase in temporal variability in inspiratory reactance at 5 Hz (X 5) (r (2) = 0.12, P = 0.04 and r (2) = 0.18, P < 0.001, respectively), and unrewarded inspiration to the decrease in X 5 at maximum lung inflation (r (2) = 0.07, P = 0.04). We conclude that symptom perception is partly explained by indexes of airway narrowing and loss of bronchodilatation with deep breath at low levels of bronchoconstriction, but by markers of ventilation heterogeneity and lung volume recruitment when bronchoconstriction becomes more severe

Risk factors for obstructive sleep apnea syndrome in children: state of the art

The obstructive sleep apnea syndrome (OSAS) represents only part of a large group of pathologies of variable entity called respiratory sleep disorders (RSD) which include simple snoring and increased upper airway resistance syndrome (UARS). Although the etiopathogenesis of adult OSAS is well known, many aspects of this syndrome in children are still debated. Its prevalence is about 2% in children from 2 to 8 years of age, mostly related to the size of the upper airways adenoid tissue. Several risk factors linked to the development of OSAS are typical of the pediatric age. The object of this paper is to analyze the state of the art on this specific topic, discussing its implications in terms of diagnosis and management