Consequences and therapy of the metabolic acidosis of chronic kidney disease

Metabolic acidosis is common in patients with chronic kidney disease (CKD), particularly once the glomerular filtration rate (GFR) falls below 25 ml/min/1.73 m2. It is usually mild to moderate in magnitude with the serum bicarbonate concentration ([HCO3−]) ranging from 12 to 23 mEq/l. Even so, it can have substantial adverse effects, including development or exacerbation of bone disease, growth retardation in children, increased muscle degradation with muscle wasting, reduced albumin synthesis with a predisposition to hypoalbuminemia, resistance to the effects of insulin with impaired glucose tolerance, acceleration of the progression of CKD, stimulation of inflammation, and augmentation of β2-microglobulin production. Also, its presence is associated with increased mortality. The administration of base to patients prior to or after initiation of dialysis leads to improvement in many of these adverse effects. The present recommendation by the National Kidney Foundation Kidney Disease Outcomes Quality Initiative (NKF KDOQI) is to raise serum [HCO3−] to ≥22 mEq/l, whereas Caring for Australians with Renal Impairment (CARI) recommends raising serum [HCO3−] to >22 mEq/l. Base administration can potentially contribute to volume overload and exacerbation of hypertension as well as to metastatic calcium precipitation in tissues. However, sodium retention is less when given as sodium bicarbonate and sodium chloride intake is concomitantly restricted. Results from various studies suggest that enhanced metastatic calcification is unlikely with the pH values achieved during conservative base administration, but the clinician should be careful not to raise serum [HCO3−] to values outside the normal range

Maximum Entropy Reconstruction Of Moment Coded Images

The maximum entropy principle (MEP) is applied to the problem of reconstructing an image from knowledge of a finite set of its moments. This new approach is compared to the existing method of moments approach and is shown to have a clear edge in performance in all of the applications attempted. Compression ratios more than twice as high as those previously achieved are possible with the new MEP method

The Eight Dimensional Quantum Hall Effect and the Octonions

We construct a generalization of the quantum Hall effect where particles move in an eight dimensional space under an SO(8) gauge field. The underlying mathematics of this particle liquid is that of the last normed division algebra, the octonions. Two fundamentally different liquids with distinct configurations spaces can be constructed, depending on whether the particles carry spinor or vector SO(8) quantum numbers. One of the liquids lives on a 20 dimensional manifold of with an internal component of SO(7) holonomy, whereas the second liquid lives on a 14 dimensional manifold with an internal component of $G_2$ holonomy.Comment: 5 page

Closed-Loop Two-Stage Stochastic Optimization of Offshore Wind Farm Collection System

A two-stage stochastic optimization model for the design of the closed-loop cable layout of an Offshore Wind Farm (OWF) is presented. The model consists on a Mixed Integer Linear Program (MILP) with scenario numeration incorporation to account for both wind power and cable failure stochasticity. The objective function supports simultaneous optimization of: (i) Initial investment (network topology and cable sizing), (ii) Total electrical power losses costs, and (iii) Reliability costs due to energy curtailment from cables failures. The mathematical optimization program is embedded in an iterative framework called PCI (Progressive Contingency Incorporation), in order to simplify the full problem while still including its global optimum. The applicability of the method is demonstrated by tackling a real-world instance. Results show the functionality of the tool in quantifying the economic profitability when applying stochastic optimization compared to a deterministic approach, given certain values of failure parameters

Pancreatitis of the Gastroduodenal Groove: A Case Report

Groove pancreatitis, a form of chronic pancreatitis affecting the head of the pancreas, is localized within the groove between the pancreas head, duodenum, and common bile duct. We report a case of a male patient with groove pancreatitis who initially underwent a duodenal preserving gastrenteranastomosis. Unfortunately, the patient's symptoms were only partially controlled, necessitating a pancreaticoduodenectomy in due course as the definite surgical restoration procedure. The surgical approach selected proved inadequate since the patient's symptoms did not resolve over time. This reflects that by-pass operations like these are not indicated for the management of patients with groove pancreatitis

Analysis of the experimental spectral coherence in the Nysted Wind Farm

In this paper, it is analysed the coherence between wind speeds located in a horizontal plane corresponding to hub height of wind turbines in a large wind farm. The coherence is calculated through real data from Nysted Offshore Wind Farm. Concretely, the wind speed measured in the 72 Wind Turbines and in 2 of the meteorological masts during 9 months. The results are analysed in the scale of power fluctuations in large offshore wind farms. This analysis shows the needing of a new spectral coherence model.The work presented in this paper has been done in the research Project ”Power Fluctuations from large offshore wind farms” financed by the Danish Transmission System Operator Energinet.dk as PSO 2004 project number 6506. A. Vigueras-Rodr´ıguez is supported by the Spanish Ministerio de Educaci´on y Ciencia through the grant program “Becas FPU” and from the national research project “ENE2006-15422-C02-02

A Wave-function for Stringy Universes

We define a wave-function for string theory cosmological backgrounds. We give a prescription for computing its norm following an earlier analysis within general relativity. Under Euclidean continuation, the cosmologies we discuss in this paper are described in terms of compact parafermionic worldsheet systems. To define the wave-function we provide a T-fold description of the parafermionic conformal field theory, and of the corresponding string cosmology. In specific examples, we compute the norm of the wave-function and comment on its behavior as a function of moduli.Comment: 30 pages, 3 figures, v3: references adde

A review on MVdc collection systems for high-power offshore wind farms

Recently, offshore renewable technologies have shown a rapid growth with the advancement in technology together with reduction of capital investment per unit size. This movement is further catalyzed by various government policy decisions and new set targets on renewable energy (RE) production. Due to higher wind speed, limited land availability and flexibility of transporting very large structures (with the increased size of a single wind turbine) offshore wind power plants provide commendable benefits over onshore wind plants. At present, only medium voltage ac is used in the offshore wind collection systems. However, the use of medium voltage direct current (MVdc) at the collection level is becoming more attractive due to advantages like lower systems losses, zero reactive power compensation and flexibility of power flow control compared to traditional ac collection systems. This paper intends to review opportunities and key challenges associated with the emerging MVdc technology for offshore wind collection systems. Attention is given to the DC wind turbine concept and selecting a suitable MVdc collection system topology with appropriate control modes