Ohgaki, Ryuichi; Wei, Ling; Yamada, Kazunori; Hara, Taiki; Kuriyama, Chiaki; Okuda, Suguru; Ueta, Kiichiro; Shiotani, Masaharu; Nagamori, Shushi; Kanai, Yoshikatsu
2016-07-01
Canagliflozin, a selective sodium/glucose cotransporter (SGLT) 2 inhibitor, suppresses the renal reabsorption of glucose and decreases blood glucose level in patients with type 2 diabetes. A characteristic of canagliflozin is its modest SGLT1 inhibitory action in the intestine at clinical dosage. To reveal its mechanism of action, we investigated the interaction of canagliflozin with SGLT1 and SGLT2. Inhibition kinetics and transporter-mediated uptake were examined in human SGLT1- or SGLT2-expressing cells. Whole-cell patch-clamp recording was conducted to examine the sidedness of drug action. Canagliflozin competitively inhibited SGLT1 and SGLT2, with high potency and selectivity for SGLT2. Inhibition constant (Ki) values for SGLT1 and SGLT2 were 770.5 and 4.0 nM, respectively. (14)C-canagliflozin was suggested to be transported by SGLT2; however, the transport rate was less than that of α-methyl-d-glucopyranoside. Canagliflozin inhibited α-methyl-d-glucopyranoside-induced SGLT1- and SGLT2-mediated inward currents preferentially from the extracellular side and not from the intracellular side. Based on the Ki value, canagliflozin is estimated to sufficiently inhibit SGLT2 from the urinary side in renal proximal tubules. The Ki value for SGLT1 suggests that canagliflozin suppresses SGLT1 in the small intestine from the luminal side, whereas it does not affect SGLT1 in the heart and skeletal muscle, considering the maximal concentration of plasma-unbound canagliflozin. Similarly, SGLT1 in the kidney would not be inhibited, thereby aiding in the prevention of hypoglycemia. After binding to SGLT2, canagliflozin may be reabsorbed by SGLT2, which leads to the low urinary excretion and prolonged drug action of canagliflozin. Copyright © 2016 by The American Society for Pharmacology and Experimental Therapeutics.
SGLT 2 Inhibitors: A New Therapeutic Target And Its Role In Current Clinical Practice
Directory of Open Access Journals (Sweden)
PV Shiji
2015-10-01
Full Text Available Diabetes, one of the major life style diseases, is associated with high morbidity and mortality owing to its microvascular and macrovascular complications. The chance of development of various complications can be effectively prevented by tight glycemic control. We have various groups of drugs like Biguanides, Sulfonyl ureas, Glitazones, Alpha-glucosidase inhibitors, Incretin based therapy, Insulin and Insulin analogues in the armamentarium to treat diabetes. But still, the number of patients attaining glycemic targets are relatively low and various adverse effect limit the use of some of these drugs, especially in special groups. Hence there is ongoing research to develop newer and newer drugs which provide sustained blood glucose reduction with minimal adverse effects. SGLT-2 inhibitors are a new group of drugs recently approved by FDA to treat Diabetes. In this review we discuss about mechanism of action, various adverse effects and the clinical role of various SGLT-2 Inhibitors.
A novel SGLT is expressed in the human kidney
Kothinti, Rajendra K.; Blodgett, Amy B.; North, Paula E.; Roman, Richard J.; Tabatabai, Niloofar M.
2012-01-01
Selective inhibitors of sodium-glucose cotransporter 2 (SGLT2)-mediated reabsorption of glucose in the proximal tubule of the kidney are being developed for the treatment of diabetes. SGLT2 shares high degree of homology with SGLT3; however, very little is known about the expression and functional role of SGLT3 in the human kidney. Indeed, the SGLT2 inhibitors that are currently in clinical trials might affect the expression and/or the activity of SGLT3. Therefore, the present study examined ...
A novel SGLT is expressed in the human kidney.
Kothinti, Rajendra K; Blodgett, Amy B; North, Paula E; Roman, Richard J; Tabatabai, Niloofar M
2012-09-05
Selective inhibitors of sodium-glucose cotransporter 2 (SGLT2)-mediated reabsorption of glucose in the proximal tubule of the kidney are being developed for the treatment of diabetes. SGLT2 shares high degree of homology with SGLT3; however, very little is known about the expression and functional role of SGLT3 in the human kidney. Indeed, the SGLT2 inhibitors that are currently in clinical trials might affect the expression and/or the activity of SGLT3. Therefore, the present study examined the expression of SGLT3 mRNA and protein in human kidney and in a human proximal tubule HK-2 cell line. The results indicated that human SGLT3 (hSGLT3) message and protein are expressed both in vivo and in vitro. We also studied the activity of hSGLT3 protein following its over-expression in mammalian kidney-derived COS-7 cells and in HK-2 cells treated with the imino sugar deoxynojirimycin (DNJ), a potent agonist of hSGLT3. Over-expression of hSGLT3 in COS-7 cells increased intracellular sodium concentration by 3-fold without affecting glucose transport. Activation of hSGLT3 with DNJ (50μM) increased sodium uptake in HK-2 cells by 5.5 fold and this effect could be completely blocked with SGLT inhibitor phlorizin (50μM). These results suggest that SGLT3 is expressed in human proximal tubular cells where it serves as a novel sodium transporter. Up-regulation of the expression of SGLT3 in the proximal tubule in diabetic patients may contribute to the elevated sodium transport in this segment of the nephron that has been postulated to promote hyperfiltration and renal injury.
LP-925219 maximizes urinary glucose excretion in mice by inhibiting both renal SGLT1 and SGLT2
Powell, David R.; Smith, Melinda G; Doree, Deon D; Harris, Angela L; Xiong, Wendy W; Mseeh, Faika; Wilson, Alan; Gopinathan, Suma; Diaz, Damaris; Goodwin, Nicole C.; Harrison, Bryce; Strobel, Eric; Rawlins, David B.; Carson, Ken; Zambrowicz, Brian
2015-01-01
Sodium-glucose cotransporter 2 (SGLT2) inhibitors are a new class of oral anti-diabetic agents that improve glycemic control by inhibiting SGLT2-mediated renal glucose reabsorption. Currently available agents increase urinary glucose excretion (UGE) to 50% of filtered glucose when SGLT2 is completely inhibited. This led us to test whether LP-925219, a small molecule dual SGLT1/SGLT2 inhibitor, increases UGE to maximal values in wild-type (WT) mice. We first tested LP-925219 inhibition of gluc...
Bounding the current in nonlinear conducting composites
Milton, Graeme W.; Serkov, Sergey K.
2000-06-01
Suppose a three-dimensional composite of two nonlinear conducting phases mixed in fixed proportions is subject to a fixed average electric field. What values can the average current take as the microstructure varies over all configurations? What microstructures produce the maximum or minimum current flow? Which microstructures are best for guiding the current in a given direction? Here, following the compensated compactness method of Tartar (1977: Estimation de coefficients homogénéisés. In: Glowinski, R., Lions, J.-L. (Eds.), Computer Methods in Applied Sciences and Engineering, Springer-Verlag Lecture Notes in Mathematics 704. Springer-Verlag, Berlin, pp. 136-212) we show how one can obtain remarkably tight bounds on the average current flow. In many, but not all cases, we find that simple laminate structures produce the maximum or minimum current flow, and are best for guiding the current in a given direction. Sometimes it is advantageous to orient the layer surfaces parallel (rather than orthogonal) to the direction of the applied field to generate the minimum current flow in that direction.
Kothinti, Rajendra K; Blodgett, Amy B; Petering, David H; Tabatabai, Niloofar M
2010-05-01
Cadmium (Cd) exposure causes glucosuria (glucose in the urine). Previously, it was shown that Cd exposure of primary cultures of mouse kidney cells (PMKC) decreased mRNA levels of the glucose transporters, SGLT1 and SGLT2 and that Sp1 from Cd-exposed cells displayed reduced binding to the GC boxes of the mouse SGLT1 promoter in vitro. Here, we identified a GC box upstream of mouse SGLT2 gene. ChIP assays on PMKC revealed that exposure to 5 microM Cd abolished Sp1 binding to SGLT1 GC box while it decreased Sp1 binding to SGLT2 GC sequence by 30% in vivo. The in vitro DNA binding assay, EMSA, demonstrated that binding of Sp1 from Cd (7.5 microM)-treated PMKC to the SGLT2 GC probe was 86% lower than in untreated cells. Sp1 is a zinc finger protein. Compared to PMKC exposed to 5 microM Cd alone, inclusion of 5 microM Zn restored SGLT1 and 2 mRNA levels by 15% and 30%, respectively. Cd (10 microM) decreased the binding of recombinant Sp1 (rhSp1) to SGLT1 and SGLT2 GC probes to 12% and 8% of untreated controls. Cd exerted no effect on GC-bound rhSp1. Co-treatment with Cd and Zn showed that added Zn significantly restored rhSp1 binding to the SGLT1 and SGLT2. Addition of Zn post Cd treatment was not stimulatory. We conclude that Cd can replace Zn in Sp1 DNA binding domain to reduce its binding to GC sites in mouse SGLT1 and SGLT2 promoters. Copyright 2010 Elsevier Inc. All rights reserved.
Bounded Algebra and Current-Mode Digital Circuits
Institute of Scientific and Technical Information of China (English)
WU Xunwei; Massoud Pedram
1999-01-01
This paper proposes two boundedarithmetic operations, which are easily realized with current signals.Based on these two operations, a bounded algebra system suitable fordescribing current-mode digital circuits is developed and itsrelationship with the Boolean algebra, which is suitable for representingvoltage-mode digital circuits, is investigated. Design procedure forcurrent-mode circuits using the proposed algebra system is demonstratedon a number of common circuit elements which are used to realizearithmetic operations, such as adders and multipliers.
Simulated annealing reveals the kinetic activity of SGLT1, a member of the LeuT structural family.
Longpré, Jean-Philippe; Sasseville, Louis J; Lapointe, Jean-Yves
2012-10-01
The Na(+)/glucose cotransporter (SGLT1) is the archetype of membrane proteins that use the electrochemical Na(+) gradient to drive uphill transport of a substrate. The crystal structure recently obtained for vSGLT strongly suggests that SGLT1 adopts the inverted repeat fold of the LeuT structural family for which several crystal structures are now available. What is largely missing is an accurate view of the rates at which SGLT1 transits between its different conformational states. In the present study, we used simulated annealing to analyze a large set of steady-state and pre-steady-state currents measured for human SGLT1 at different membrane potentials, and in the presence of different Na(+) and α-methyl-d-glucose (αMG) concentrations. The simplest kinetic model that could accurately reproduce the time course of the measured currents (down to the 2 ms time range) is a seven-state model (C(1) to C(7)) where the binding of the two Na(+) ions (C(4)→C(5)) is highly cooperative. In the forward direction (Na(+)/glucose influx), the model is characterized by two slow, electroneutral conformational changes (59 and 100 s(-1)) which represent reorientation of the free and of the fully loaded carrier between inside-facing and outside-facing conformations. From the inward-facing (C(1)) to the outward-facing Na-bound configuration (C(5)), 1.3 negative elementary charges are moved outward. Although extracellular glucose binding (C(5)→C(6)) is electroneutral, the next step (C(6)→C(7)) carries 0.7 positive charges inside the cell. Alignment of the seven-state model with a generalized model suggested by the structural data of the LeuT fold family suggests that electrogenic steps are associated with the movement of the so-called thin gates on each side of the substrate binding site. To our knowledge, this is the first model that can quantitatively describe the behavior of SGLT1 down to the 2 ms time domain. The model is highly symmetrical and in good agreement with the
Mende, Christian W
2017-03-01
Patients with type 2 diabetes (T2D) often have coexisting chronic kidney disease (CKD). However, healthy renal function is crucial in maintaining glucose homeostasis, assuring that almost all of the filtered glucose is reabsorbed by the sodium glucose cotransporters (SGLTs) SGLT-1 and SGLT-2. In diabetes, an increased amount of glucose is filtered by the kidneys and SGLT-2 is upregulated, leading to increased glucose absorption and worsening hyperglycemia. Prolonged hyperglycemia contributes to the development of CKD by inducing metabolic and hemodynamic changes in the kidneys. Due to the importance of SGLT-2 in regulating glucose levels, investigation into SGLT-2 inhibitors was initiated as a glucose-dependent mechanism to control hyperglycemia, and there are three agents currently approved for use in the United States: dapagliflozin, canagliflozin, and empagliflozin. SGLT-2 inhibitors have been shown to reduce glycated hemoglobin (A1C), weight, and blood pressure, which not only affects glycemic control, but may also help slow the progression of renal disease by impacting the underlying mechanisms of kidney injury. In addition, SGLT-2 inhibitors have shown reductions in albuminuria, uric acid, and an increase in magnesium. Caution is advised when prescribing SGLT-2 inhibitors to patients with moderately impaired renal function and those at risk for volume depletion and hypotension. Published data on slowing of the development, as well as progression of CKD, is a hopeful indicator for the possible renal protection potential of this drug class. This narrative review provides an in-depth discussion of the interplay between diabetes, SGLT-2 inhibitors, and factors that affect kidney function.
Conformational Dynamics of hSGLT1 during Na+/Glucose Cotransport
DEFF Research Database (Denmark)
Loo, D. D.; Hirayama, B. A.; Karakossian, M. H.
2006-01-01
. voltage (Q-V) and fluorescence vs. voltage ( F-V) relations (for medium and slow components) obeyed Boltzmann relations with similar parameters: z (apparent valence of voltage sensor) 1; and V0.5 (midpoint voltage) between -15 and -40 mV. Sugar induced an inward current (Na+/glucose cotransport......This study examines the conformations of the Na+/glucose cotransporter (SGLT1) during sugar transport using charge and fluorescence measurements on the human SGLT1 mutant G507C expressed in Xenopus oocytes. The mutant exhibited similar steady-state and presteady-state kinetics as wild-type SGLT1...
SGLT inhibitors: a novel target for diabetes.
Kanwal, Abhinav; Banerjee, Sanjay K
2013-01-01
Inhibiting sodium-glucose co-transporters (SGLT1/SGLT2), which have a key role in the absorption of glucose in the kidney and/or GI tract has been proposed as a novel therapeutic strategy for diabetes. Thus, screening and patenting of chemical compounds for SGLT1/SGLT2 gets more importance in the development of new drugs in diabetes. Several companies are developing SGLT inhibitors, some of which are now in various stages of clinical development. Some molecules in the pipeline, including dapagliflozin, canagliflozin, ASP1941, BI10773, LX4211, RG7201 and TS071, are at various stages of drug development. This patent review presents the overall progress carried out in the development of SGLT inhibitors over the last decade with the active participation of various pharmaceutical companies. This class of drug is anticipated to have a large impact on diabetes field and predicting to attain a blockbuster status.
SGLT inhibitors in management of diabetes.
Tahrani, Abd A; Barnett, Anthony H; Bailey, Clifford J
2013-10-01
The two main sodium-glucose cotransporters (SGLTs), SGLT1 and SGLT2, provide new therapeutic targets to reduce hyperglycaemia in patients with diabetes. SGLT1 enables the small intestine to absorb glucose and contributes to the reabsorption of glucose filtered by the kidney. SGLT2 is responsible for reabsorption of most of the glucose filtered by the kidney. Inhibitors with varying specificities for these transporters (eg, dapagliflozin, canagliflozin, and empagliflozin) can slow the rate of intestinal glucose absorption and increase the renal elimination of glucose into the urine. Results of randomised clinical trials have shown the blood glucose-lowering efficacy of SGLT inhibitors in type 2 diabetes when administered as monotherapy or in addition to other glucose-lowering therapies including insulin. Increased renal glucose elimination also assists weight loss and could help to reduce blood pressure. Effective SGLT2 inhibition needs adequate glomerular filtration and might increase risk of urinary tract and genital infection, and excessive inhibition of SGLT1 can cause gastro-intestinal symptoms. However, the insulin-independent mechanism of action of SGLT inhibitors seems to offer durable glucose-lowering efficacy with low risk of clinically significant hypoglycaemia at any stage in the natural history of type 2 diabetes. SGLT inhibition might also be considered in conjunction with insulin therapy in type 1 diabetes. Copyright © 2013 Elsevier Ltd. All rights reserved.
Current understanding of organically bound tritium (OBT) in the environment.
Kim, S B; Baglan, N; Davis, P A
2013-12-01
It has become increasingly recognized that organically bound tritium (OBT) is the more significant tritium fraction with respect to understanding tritium behaviour in the environment. There are many different terms associated with OBT; such as total OBT, exchangeable OBT, non-exchangeable OBT, soluble OBT, insoluble OBT, tritiated organics, and buried tritium, etc. A simple classification is required to clarify understanding within the tritium research community. Unlike for tritiated water (HTO), the environmental quantification and behaviour of OBT are not well known. Tritiated water cannot bio-accumulate in the environment. However, it is not clear whether or not this is the case for OBT. Even though OBT can be detected in terrestrial biological materials, aquatic biological materials and soil samples, its behaviour is still in question. In order to evaluate the radiation dose from OBT accurately, further study will be required to understand OBT measurements and determine OBT fate in the environment. The relationship between OBT speciation and the OBT/HTO ratio in environmental samples will be useful in this regard, providing information on the previous tritium exposure conditions in the environment and the current tritium dynamics. Crown Copyright © 2013. Published by Elsevier Ltd. All rights reserved.
SGLT2 inhibitors: a promising new therapeutic option for treatment of type 2 diabetes mellitus.
Misra, Monika
2013-03-01
Hyperglycemia is an important pathogenic component in the development of microvascular and macrovascular complications in type 2 diabetes mellitus. Inhibition of renal tubular glucose reabsorption that leads to glycosuria has been proposed as a new mechanism to attain normoglycemia and thus prevent and diminish these complications. Sodium glucose cotransporter 2 (SGLT2) has a key role in reabsorption of glucose in kidney. Competitive inhibitors of SGLT2 have been discovered and a few of them have also been advanced in clinical trials for the treatment of diabetes. To discuss the therapeutic potential of SGLT2 inhibitors currently in clinical development. A number of preclinical and clinical studies of SGLT2 inhibitors have demonstrated a good safety profile and beneficial effects in lowering plasma glucose levels, diminishing glucotoxicity, improving glycemic control and reducing weight in diabetes. Of all the SGLT2 inhibitors, dapagliflozin is a relatively advanced compound with regards to clinical development. SGLT2 inhibitors are emerging as a promising therapeutic option for the treatment of diabetes. Their unique mechanism of action offers them the potential to be used in combination with other oral anti-diabetic drugs as well as with insulin. © 2012 The Author. JPP © 2012 Royal Pharmaceutical Society.
Vrhovac, Ivana; Balen Eror, Daniela; Klessen, Dirk; Burger, Christa; Breljak, Davorka; Kraus, Ognjen; Radović, Nikola; Jadrijević, Stipe; Aleksic, Ivan; Walles, Thorsten; Sauvant, Christoph; Sabolić, Ivan; Koepsell, Hermann
2015-09-01
Novel affinity-purified antibodies against human SGLT1 (hSGLT1) and SGLT2 (hSGLT2) were used to localize hSGLT2 in human kidney and hSGLT1 in human kidney, small intestine, liver, lung, and heart. The renal locations of both transporters largely resembled those in rats and mice; hSGLT2 and SGLT1 were localized to the brush border membrane (BBM) of proximal tubule S1/S2 and S3 segments, respectively. Different to rodents, the renal expression of hSGLT1 was absent in thick ascending limb of Henle (TALH) and macula densa, and the expression of both hSGLTs was sex-independent. In small intestinal enterocytes, hSGLT1 was localized to the BBM and subapical vesicles. Performing double labeling with glucagon-like peptide 1 (GLP-1) or glucose-dependent insulinotropic peptide (GIP), hSGLT1 was localized to GLP-1-secreting L cells and GIP-secreting K cells as has been shown in mice. In liver, hSGLT1 was localized to biliary duct cells as has been shown in rats. In lung, hSGLT1 was localized to alveolar epithelial type 2 cells and to bronchiolar Clara cells. Expression of hSGLT1 in Clara cells was verified by double labeling with the Clara cell secretory protein CC10. Double labeling of human heart with aquaporin 1 immunolocalized the hSGLT1 protein in heart capillaries rather than in previously assumed myocyte sarcolemma. The newly identified locations of hSGLT1 implicate several extra renal functions of this transporter, such as fluid absorption in the lung, energy supply to Clara cells, regulation of enteroendocrine cells secretion, and release of glucose from heart capillaries. These functions may be blocked by reversible SGLT1 inhibitors which are under development.
SGLT-2 inhibitors: the glucosuric antidiabetics
Rekha Thaddanee; Ajeet Kumar Khilnani; Gurudas Khilnani
2013-01-01
Despite availability of a number of oral antidiabetics, a sizeable population of diabetics remains uncontrolled. Thus there is growing need of new group of drugs for diabetic control. Understanding renal conservation of glucose by efficient reabsorption through sodium glucose cotransporter-2 (SGLT-2) has paved way for development of an entirely new group of drugs, the SGLT-2 inhibitors. These glucosuric antidiabetic agents have shown promise in early clinical studies. Canagliflozin is recentl...
SGLT-2 inhibition in patients with kidney disease.
Gilbert, R E
2014-12-01
Accustomed to managing diabetes with agents that mostly act by modulating the secretion and actions of insulin, with the advent of sodium-glucose linked transporter-2 (SGLT-2) inhibitors, physicians are now aware that the kidney also needs to be considered in the spectrum of action of anti-hyperglycaemic agents. Though familiar with the need for dose adjustment when prescribing many of our current anti-hyperglycaemic drugs in the setting of kidney dysfunction, with the SGLT-2 inhibitors pharmacodynamic as well as pharmacokinetic aspects also need to be considered. Finally, through their ability to reduce intraglomerular pressure, systemic blood pressure and plasma uric acid concentration, the SGLT-2 inhibitors offers the possibility of kidney protection. An hypothesis that will need to be tested with long term studies that address changes in the kidney beyond albuminuria, assessing the rate of decline in glomerular filtration rate and 'hard'kidneyrelated endpoints such as the need for renal replacement therapy (dialysis, transplantation) will be important in this setting.
Rieg, Timo; Masuda, Takahiro; Gerasimova, Maria; Mayoux, Eric; Platt, Kenneth; Powell, David R.; Thomson, Scott C.; Koepsell, Hermann; Vallon, Volker
2013-01-01
In the kidney, the sodium-glucose cotransporters SGLT2 and SGLT1 are thought to account for >90 and ∼3% of fractional glucose reabsorption (FGR), respectively. However, euglycemic humans treated with an SGLT2 inhibitor maintain an FGR of 40–50%, mimicking values in Sglt2 knockout mice. Here, we show that oral gavage with a selective SGLT2 inhibitor (SGLT2-I) dose dependently increased urinary glucose excretion (UGE) in wild-type (WT) mice. The dose-response curve was shifted leftward and the ...
Update on developments with SGLT2 inhibitors in the management of type 2 diabetes
Directory of Open Access Journals (Sweden)
Nauck MA
2014-09-01
Full Text Available Michael A Nauck Department of Internal Medicine, Diabeteszentrum Bad Lauterberg, Bad Lauterberg im Harz, Germany Abstract: The importance of the kidney's role in glucose homeostasis has gained wider understanding in recent years. Consequently, the development of a new pharmacological class of anti-diabetes agents targeting the kidney has provided new treatment options for the management of type 2 diabetes mellitus (T2DM. Sodium glucose co-transporter type 2 (SGLT2 inhibitors, such as dapagliflozin, canagliflozin, and empagliflozin, decrease renal glucose reabsorption, which results in enhanced urinary glucose excretion and subsequent reductions in plasma glucose and glycosylated hemoglobin concentrations. Modest reductions in body weight and blood pressure have also been observed following treatment with SGLT2 inhibitors. SGLT2 inhibitors appear to be generally well tolerated, and have been used safely when given as monotherapy or in combination with other oral anti-diabetes agents and insulin. The risk of hypoglycemia is low with SGLT2 inhibitors. Typical adverse events appear to be related to the presence of glucose in the urine, namely genital mycotic infection and lower urinary tract infection, and are more often observed in women than in men. Data from long-term safety studies with SGLT2 inhibitors and from head-to-head SGLT2 inhibitor comparator studies are needed to fully determine their benefit–risk profile, and to identify any differences between individual agents. However, given current safety and efficacy data, SGLT2 inhibitors may present an attractive option for T2DM patients who are failing with metformin monotherapy, especially if weight is part of the underlying treatment consideration. Keywords: anti-diabetes agents, efficacy, hyperglycemia, safety, sodium glucose co-transporter type 2 inhibitors, type 2 diabetes mellitus
Effect of the bound nucleon form factors on charged-current neutrino-nucleus scattering
Tsushima, K; Saitô, K; Kim, Hungchong
2003-01-01
We study the effect of bound nucleon form factors on charged-current neutrino-nucleus scattering. The bound nucleon form factors associated with the vector and axial-vector currents are calculated in the quark-meson coupling model. We compute the inclusive $^{12}$C($nu_mu,mu^-$)$X$ differential and total cross sections, which have been measured by the LSND collaboration at Los Alamos, using a relativistic Fermi gas model with the calculated bound nucleon form factors. It is shown that the bound nucleon form factors reduce the total cross section by about 8% relative to that calculated with the free nucleon form factors, where most of the conventional calculations overestimate the total cross section data by about 30% to 100%.
Current conservation in electrodisintegration of a bound system in the Bethe-Salpeter approach
Karmanov, V A
2014-01-01
Using our solutions of the Bethe-Salpeter equation with OBE kernel in Minkowski space both for the bound and scattering states, we calculate the transition form factors for electrodisintegration of the bound system which determine the electromagnetic current J of this process. Special emphasis is put on verifying the gauge invariance which should manifest itself in the current conservation. We find that for any value of the momentum transfer q the contributions of the plane wave and the final state interaction to the quantity J.q cancel each other thus providing J.q=0. However, this cancellation is obtained only if the initial Bethe-Salpeter amplitude (bound state), the final one (scattering state) and the current operator are strictly consistent with each other. A reliable result for the transition form factor can be found only in this case.
A single amino acid change converts the sugar sensor SGLT3 into a sugar transporter.
Directory of Open Access Journals (Sweden)
Laura Bianchi
Full Text Available BACKGROUND: Sodium-glucose cotransporter proteins (SGLT belong to the SLC5A family, characterized by the cotransport of Na(+ with solute. SGLT1 is responsible for intestinal glucose absorption. Until recently the only role described for SGLT proteins was to transport sugar with Na(+. However, human SGLT3 (hSGLT3 does not transport sugar but causes depolarization of the plasma membrane when expressed in Xenopus oocytes. For this reason SGLT3 was suggested to be a sugar sensor rather than a transporter. Despite 70% amino acid identity between hSGLT3 and hSGLT1, their sugar transport, apparent sugar affinities, and sugar specificity differ greatly. Residue 457 is important for the function of SGLT1 and mutation at this position in hSGLT1 causes glucose-galactose malabsorption. Moreover, the crystal structure of vibrio SGLT reveals that the residue corresponding to 457 interacts directly with the sugar molecule. We thus wondered if this residue could account for some of the functional differences between SGLT1 and SGLT3. METHODOLOGY/PRINCIPAL FINDINGS: We mutated the glutamate at position 457 in hSGLT3 to glutamine, the amino acid present in all SGLT1 proteins, and characterized the mutant. Surprisingly, we found that E457Q-hSGLT3 transported sugar, had the same stoichiometry as SGLT1, and that the sugar specificity and apparent affinities for most sugars were similar to hSGLT1. We also show that SGLT3 functions as a sugar sensor in a living organism. We expressed hSGLT3 and E457Q-hSGLT3 in C. elegans sensory neurons and found that animals sensed glucose in an hSGLT3-dependent manner. CONCLUSIONS/SIGNIFICANCE: In summary, we demonstrate that hSGLT3 functions as a sugar sensor in vivo and that mutating a single amino acid converts this sugar sensor into a sugar transporter similar to SGLT1.
Stored Energy of Coupled Electric and Magnetic Currents and the Lower Bound on Q
DEFF Research Database (Denmark)
Kim, Oleksiy S.
2015-01-01
—New expressions for the stored energy and radiated power of an arbitrary combination of electric and magnetic currents in free space are presented. These expressions enable the calculation of the fundamental lower bound on Q for arbitraryshaped electrically small antennas of finite size....
Lower bounds for ballistic current and noise in non-equilibrium quantum steady states
Directory of Open Access Journals (Sweden)
Benjamin Doyon
2015-03-01
Full Text Available Let an infinite, homogeneous, many-body quantum system be unitarily evolved for a long time from a state where two halves are independently thermalized. One says that a non-equilibrium steady state emerges if there are nonzero steady currents in the central region. In particular, their presence is a signature of ballistic transport. We analyze the consequences of the current observable being a conserved density; near equilibrium this is known to give rise to linear wave propagation and a nonzero Drude peak. Using the Lieb–Robinson bound, we derive, under a certain regularity condition, a lower bound for the non-equilibrium steady-state current determined by equilibrium averages. This shows and quantifies the presence of ballistic transport far from equilibrium. The inequality suggests the definition of “nonlinear sound velocities”, which specialize to the sound velocity near equilibrium in non-integrable models, and “generalized sound velocities”, which encode generalized Gibbs thermalization in integrable models. These are bounded by the Lieb–Robinson velocity. The inequality also gives rise to a bound on the energy current noise in the case of pure energy transport. We show that the inequality is satisfied in many models where exact results are available, and that it is saturated at one-dimensional criticality.
Dapagliflozin, SGLT2 Inhibitor, Attenuates Renal Ischemia-Reperfusion Injury
Yoon-Kyung Chang; Hyunsu Choi; Jin Young Jeong; Ki-Ryang Na; Kang Wook Lee; Beom Jin Lim; Dae Eun Choi
2016-01-01
Dapagliflozin, a new type of drug used to treat diabetes mellitus (DM), is a sodium/glucose cotransporter 2 (SGLT2) inhibitor. Although some studies showed that SGLT2 inhibition attenuated reactive oxygen generation in diabetic kidney the role of SGLT2 inhibition is unknown. We evaluated whether SLT2 inhibition has renoprotective effects in ischemia-reperfusion (IR) models. We evaluated whether dapagliflozin reduces renal damage in IR mice model. In addition, hypoxic HK2 cells were treated wi...
SGLT2 Inhibitors: Benefit/Risk Balance.
Scheen, André J
2016-10-01
Inhibitors of sodium-glucose cotransporters type 2 (SGLT2) reduce hyperglycemia by increasing urinary glucose excretion. They have been evaluated in patients with type 2 diabetes treated with diet/exercise, metformin, dual oral therapy or insulin. Three agents are available in Europe and the USA (canagliflozin, dapagliflozin, empagliflozin) and others are commercialized in Japan or in clinical development. SGLT2 inhibitors reduce glycated hemoglobin, with a minimal risk of hypoglycemia. They exert favorable effects beyond glucose control with consistent body weight, blood pressure, and serum uric acid reductions. Empagliflozin showed remarkable reductions in cardiovascular/all-cause mortality and in hospitalization for heart failure in patients with previous cardiovascular disease. Positive renal outcomes were also shown with empagliflozin. Mostly reported adverse events are genital mycotic infections, while urinary tract infections and events linked to volume depletion are rather rare. Concern about a risk of ketoacidosis and bone fractures has been recently raised, which deserves caution and further evaluation.
Lu, Yasong; Griffen, Steven C.; Boulton, David W.; Leil, Tarek A.
2014-01-01
In the kidney, glucose in glomerular filtrate is reabsorbed primarily by sodium-glucose cotransporters 1 (SGLT1) and 2 (SGLT2) along the proximal tubules. SGLT2 has been characterized as a high capacity, low affinity pathway responsible for reabsorption of the majority of filtered glucose in the early part of proximal tubules, and SGLT1 reabsorbs the residual glucose in the distal part. Inhibition of SGLT2 is a viable mechanism for removing glucose from the body and improving glycemic control...
Yasong eLu; Griffen, Steven C.; Boulton, David W.; Leil, Tarek A.
2014-01-01
In the kidney, glucose in glomerular filtrate is reabsorbed primarily by sodium-glucose cotransporters 1 (SGLT1) and 2 (SGLT2) along the proximal tubules. SGLT2 has been characterized as a high capacity, low affinity pathway responsible for reabsorption of the majority of filtered glucose in the early part of proximal tubules, and SGLT1 reabsorbs the residual glucose in the distal part. Inhibition of SGLT2 is a viable mechanism for removing glucose from the body and improving glycemic control...
Yasong eLu; Griffen, Steven C.; Boulton, David W.; Leil, Tarek A.
2014-01-01
In the kidney, glucose in glomerular filtrate is reabsorbed primarily by sodium-glucose cotransporters 1 (SGLT1) and 2 (SGLT2) along the proximal tubules. SGLT2 has been characterized as a high capacity, low affinity pathway responsible for reabsorption of the majority of filtered glucose in the early part of proximal tubules, and SGLT1 reabsorbs the residual glucose in the distal part. Inhibition of SGLT2 is a viable mechanism for removing glucose from the body and improving glycemic control...
Lu, Yasong; Griffen, Steven C.; Boulton, David W.; Leil, Tarek A.
2014-01-01
In the kidney, glucose in glomerular filtrate is reabsorbed primarily by sodium-glucose cotransporters 1 (SGLT1) and 2 (SGLT2) along the proximal tubules. SGLT2 has been characterized as a high capacity, low affinity pathway responsible for reabsorption of the majority of filtered glucose in the early part of proximal tubules, and SGLT1 reabsorbs the residual glucose in the distal part. Inhibition of SGLT2 is a viable mechanism for removing glucose from the body and improving glycemic control...
Intestinal SGLT1 in metabolic health and disease.
Lehmann, Anders; Hornby, Pamela J
2016-06-01
The Na(+)-glucose cotransporter 1 (SGLT1/SLC5A1) is predominantly expressed in the small intestine. It transports glucose and galactose across the apical membrane in a process driven by a Na(+) gradient created by Na(+)-K(+)-ATPase. SGLT2 is the major form found in the kidney, and SGLT2-selective inhibitors are a new class of treatment for type 2 diabetes mellitus (T2DM). Recent data from patients treated with dual SGLT1/2 inhibitors or SGLT2-selective drugs such as canagliflozin (SGLT1 IC50 = 663 nM) warrant evaluation of SGLT1 inhibition for T2DM. SGLT1 activity is highly dynamic, with modulation by multiple mechanisms to ensure maximal uptake of carbohydrates (CHOs). Intestinal SGLT1 inhibition lowers and delays the glucose excursion following CHO ingestion and augments glucagon-like peptide-1 (GLP-1) and peptide YY (PYY) secretion. The latter is likely due to increased glucose exposure of the colonic microbiota and formation of metabolites such as L cell secretagogues. GLP-1 and PYY secretion suppresses food intake, enhances the ileal brake, and has an incretin effect. An increase in colonic microbial production of propionate could contribute to intestinal gluconeogenesis and mediate positive metabolic effects. On the other hand, a threshold of SGLT1 inhibition that could lead to gastrointestinal intolerability is unclear. Altered Na(+) homeostasis and increased colonic CHO may result in diarrhea and adverse gastrointestinal effects. This review considers the potential mechanisms contributing to positive metabolic and negative intestinal effects. Compounds that inhibit SGLT1 must balance the modulation of these mechanisms to achieve therapeutic efficacy for metabolic diseases. Copyright © 2016 the American Physiological Society.
Lu, Yasong; Griffen, Steven C; Boulton, David W; Leil, Tarek A
2014-01-01
In the kidney, glucose in glomerular filtrate is reabsorbed primarily by sodium-glucose cotransporters 1 (SGLT1) and 2 (SGLT2) along the proximal tubules. SGLT2 has been characterized as a high capacity, low affinity pathway responsible for reabsorption of the majority of filtered glucose in the early part of proximal tubules, and SGLT1 reabsorbs the residual glucose in the distal part. Inhibition of SGLT2 is a viable mechanism for removing glucose from the body and improving glycemic control in patients with diabetes. Despite demonstrating high levels (in excess of 80%) of inhibition of glucose transport by SGLT2 in vitro, potent SGLT2 inhibitors, e.g., dapagliflozin and canagliflozin, inhibit renal glucose reabsorption by only 30-50% in clinical studies. Hypotheses for this apparent paradox are mostly focused on the compensatory effect of SGLT1. The paradox has been explained and the role of SGLT1 demonstrated in the mouse, but direct data in humans are lacking. To further explore the roles of SGLT1/2 in renal glucose reabsorption in humans, we developed a systems pharmacology model with emphasis on SGLT1/2 mediated glucose reabsorption and the effects of SGLT2 inhibition. The model was calibrated using robust clinical data in the absence or presence of dapagliflozin (DeFronzo et al., 2013), and evaluated against clinical data from the literature (Mogensen, 1971; Wolf et al., 2009; Polidori et al., 2013). The model adequately described all four data sets. Simulations using the model clarified the operating characteristics of SGLT1/2 in humans in the healthy and diabetic state with or without SGLT2 inhibition. The modeling and simulations support our proposition that the apparent moderate, 30-50% inhibition of renal glucose reabsorption observed with potent SGLT2 inhibitors is a combined result of two physiological determinants: SGLT1 compensation and residual SGLT2 activity. This model will enable in silico inferences and predictions related to SGLT1/2 modulation.
Directory of Open Access Journals (Sweden)
Francisco Castaneda, Antje Burse, Wilhelm Boland, Rolf K-H. Kinne
2007-01-01
Full Text Available The treatment of diabetes has been mainly focused on maintaining normal blood glucose concentrations. Insulin and hypoglycemic agents have been used as standard therapeutic strategies. However, these are characterized by limited efficacy and adverse side effects, making the development of new therapeutic alternatives mandatory. Inhibition of glucose reabsorption in the kidney, mediated by SGLT1 or SGLT2, represents a promising therapeutic approach. Therefore, the aim of the present study was to evaluate the effect of thioglycosides on human SGLT1 and SGLT2. For this purpose, stably transfected Chinese hamster ovary (CHO cells expressing human SGLT1 and SGLT2 were used. The inhibitory effect of thioglycosides was assessed in transport studies and membrane potential measurements, using α-methyl-glucoside uptake and fluorescence resonance energy transfer, respectively. We found that some thioglycosides inhibited hSGLT more strongly than phlorizin. Specifically, thioglycoside I (phenyl-1'-thio-β-D-glucopyranoside inhibited hSGLT2 stronger than hSGLT1 and to a larger extent than phlorizin. Thioglycoside VII (2-hydroxymethyl-phenyl-1'-thio-β-D-galacto-pyranoside had a pronounced inhibitory effect on hSGLT1 but not on hSGLT2. Kinetic studies confirmed the inhibitory effect of these thioglycosides on hSGLT1 or hSGLT2, demonstrating competitive inhibition as the mechanism of action. Therefore, these thioglycosides represent promising therapeutic agents for the control of hyperglycemia in patients with diabetes.
Blanco, Ayelén Melisa; Bertucci, Juan Ignacio; Ramesh, Naresh; Delgado, María Jesús; Valenciano, Ana Isabel; Unniappan, Suraj
2017-01-01
Glucose homeostasis is an important biological process that involves a variety of regulatory mechanisms. This study aimed to determine whether ghrelin, a multifunctional gut-brain hormone, modulates intestinal glucose transport in goldfish (Carassius auratus). Three intestinal glucose transporters, the facilitative glucose transporter 2 (GLUT2), and the sodium/glucose co-transporters 1 (SGLT1) and 2 (SGLT2), were studied. Immunostaining of intestinal sections found colocalization of ghrelin and GLUT2 and SGLT2 in mucosal cells. Some cells containing GLUT2, SGLT1 and SGLT2 coexpressed the ghrelin/growth hormone secretagogue receptor 1a (GHS-R1a). Intraperitoneal glucose administration led to a significant increase in serum ghrelin levels, as well as an upregulation of intestinal preproghrelin, ghrelin O-acyltransferase and ghs-r1 expression. In vivo and in vitro ghrelin treatment caused a concentration- and time-dependent modulation (mainly stimulatory) of GLUT2, SGLT1 and SGLT2. These effects were abolished by the GHS-R1a antagonist [D-Lys3]-GHRP-6 and the phospholipase C inhibitor U73122, suggesting that ghrelin actions on glucose transporters are mediated by GHS-R1a via the PLC/PKC signaling pathway. Finally, ghrelin stimulated the translocation of GLUT2 into the plasma membrane of goldfish primary intestinal cells. Overall, data reported here indicate an important role for ghrelin in the modulation of glucoregulatory machinery and glucose homeostasis in fish. PMID:28338019
The Role of the Kidney and SGLT2 Inhibitors in Type 2 Diabetes.
Katz, Pamela M; Leiter, Lawrence A
2015-12-01
Effective glycemic control reduces the risk for diabetes-related complications. However, the majority of patients with type 2 diabetes still do not achieve glycemic targets. Beyond metformin therapy, current practice guidelines for the management of type 2 diabetes recommend individualized treatment based on patient and agent characteristics. The sodium glucose cotransporter type 2 (SGLT2) inhibitors represent a novel treatment strategy, independent of impaired beta-cell function and insulin resistance. SGLT2 inhibitors decrease renal glucose reabsorption, thereby increasing urinary glucose excretion with subsequent reduction in plasma glucose levels and glycosylated hemoglobin concentrations. Current evidence suggests that they are effective as monotherapy or as add-ons to metformin either alone, or in combination with other oral glucose-lowering agents or insulin. They are generally well tolerated, though rates of lower urinary tract and genital mycotic infections are slightly increased. The advantages of this class include modest reductions in body weight and blood pressure, and low risk for hypoglycemia. Long-term safety data and results of ongoing cardiovascular outcome studies are awaited so we can fully understand the role that SGLT2 inhibitors will play in the comprehensive management of type 2 diabetes.
Currents at the sills bounding Delfin Basin in the northern Gulf of California
Lopez, M.; Candela, J.
2013-05-01
One-year-long currents at the two sills bounding Delfin basin (maximum depth ˜900 m), are analyzed. The Delfin (DEL) sill (˜400 m depth) has the largest mean velocities near the bottom in an overflow that discharges water into the Delfin Basin (roughly towards the head of the gulf), whereas the Ballenas Channel (BC) sill (˜600 m depth) has the largest mean velocities close to the surface which also flow towards the head of the gulf. The energy of the subinertial current fluctuations is also quite different. Most of the energy at the DEL sill is concentrated in the lowest frequencies (periods > 15 days). In the case of the BC sill, the spectra are not red and much of the energy is concentrated at periods ≤ 15 days except close to the surface, where most the energy is also concentrated in the lowest frequencies associated with the current fluctuations of the mean near-surface current towards the head of the gulf. Near-bottom current fluctuations towards the head of the gulf at the overflow of the DEL sill are well correlated with intermediate and deeper currents towards the mouth of the gulf, as well as with surface currents towards the head of the gulf at the BC sill for periods ≥ 20 days. Transport of the overflow also has the largest coherences with near-surface currents at the BC sill for periods ≥ 20 days, but there is also significant coherence with deeper currents at the same low frequencies. The relationship between the overflow and the exchange at the BC sill is also clearly borne out by the first empirical mode of currents at both locations. This is interpreted as part of the exchange of the northern gulf by which fluctuations of the near-bottom flow into the deepest basins are compensated by fluctuations of the near-surface flow out of the same basins. In addition, near-bottom transport and currents at the DEL sill are coherent with deep currents at the CB sill at the shorter periods of 10 and 3.2 days. At these periods, there is also good
Takebayashi, Kohzo; Inukai, Toshihiko
2017-09-01
Sodium glucose cotransporter 2 (SGLT2) inhibitors are a new class of antidiabetic drugs that improve glycemic control by inhibiting reabsorption of glucose filtered through the renal glomerulus. Use of drugs in this class has increased because of their effect of decreasing body weight and a low risk for hypoglycemia, in addition to a relatively strong glucose-lowering effect. SGLT2 inhibitors such as canagliflozin and sotagliflozin (a SGLT1/SGLT2 dual inhibitor) also have a mild or moderate intestinal and renal SGLT1 inhibitory effect because of their relatively weak selectivity for SGLT2 over SGLT1. Recent evidence shows that these SGLT2 inhibitors with low SGLT2/SGLT1 selectivity elevate the level of circulating glucagon like peptide-1 (GLP-1), an incretin hormone that promotes insulin secretion in pancreatic β cells. This effect probably occurs partly via inhibition of intestinal SGLT1, and the elevation of active GLP-1 levels is especially apparent when these drugs are co-administered with dipeptidyl peptidase 4 (DPP4) inhibitors. These findings suggest that a combination of canagliflozin or sotagliflozin and a DPP4 inhibitor can provide a beneficial effect associated with elevation of circulating active GLP-1 and may serve as a treatment for patients with type 2 diabetes.
[Contributions of SGLT-2 and new drugs under investigation].
Mediavilla Bravo, J J
2014-07-01
DeFronzo spoke of the "ominous octet", in which he referred to the existence of distinct pathways and organs related to the physiopathology of type 2 diabetes mellitus (DM2). One of these key organs is the kidney, which plays an important role in regulating glucose metabolism through gluconeogenesis and through glomerular filtration and glucose reabsorption in the proximal convoluted tubules. Approximately 180 g of glucose are filtered to the renal tubule from the blood stream through the glomerulus. The filtrate is subsequently reabsorbed from the tubules to the peritubular capillaries through the action of sodium glucose cotransporters (SGLT). There are 2 main cotransporters in the kidney, SGLT1 and SGLT2, which reabsorb the glucose (10% and 90%, respectively) and return it to the blood. In persons with DM2, SGLT2 is increased, leading to greater renal absorption of glucose, which has adverse effects as it contributes to the maintenance of hyperglycemia. Selective pharmacological SGLT2 inhibition increases renal glucose excretion and secondarily reduces its plasma values. SGLT2 inhibitors act exclusively on the kidney, reduce glycosylated hemoglobin (HbA1c) by about 0.66%, decrease blood pressure, and induce a weight loss of approximately 1.8 kg. These drugs have a low risk of hypoglycemia but carry an increased risk of genitourinary infections. Several clinical trials have shown that dapagliflozin (10mg/day), the first SGLT2 inhibitor commercialized in Spain, produces a statistically significant reduction in HbA1c of 0.82-0.97%, both in monotherapy and in combination with metformin, glimepiride, pioglitazone, or insulin. Its use produces a weight loss of between 2 and 3 kg and reduces both systolic and diastolic blood pressure, while the risk of hypoglycemias is low.
Bergen-Cico, Dessa K.; Lape, Megan E.
2013-01-01
Background: Alcohol and marijuana are the most commonly used psychoactive substances; however, the sequencing and relationship between age of first use and continued current problematic use among college-bound emerging adults is not well understood. Methods: This is a cross-sectional study of current and historical alcohol and marijuana use among…
Grempler, Rolf; Augustin, Robert; Froehner, Stefanie; Hildebrandt, Tobias; Simon, Eric; Mark, Michael; Eickelmann, Peter
2012-02-03
Sodium glucose cotransporters (SGLT) actively catalyse carbohydrate transport across cellular membranes. Six of the 12 known SGLT family members have the capacity to bind and/or transport monosaccharides (SGLT-1 to 6); of these, all but SGLT-5 have been characterised. Here we demonstrate that human SGLT-5 is exclusively expressed in the kidney. Four splice variants were detected and the most abundant SGLT-5-mRNA was functionally characterised. SGLT-5 mediates sodium-dependent [(14)C]-α-methyl-D-glucose (AMG) transport that can be inhibited by mannose, fructose, glucose, and galactose. Uptake studies using demonstrated high capacity transport for mannose and fructose and, to a lesser extent, glucose, AMG, and galactose. SGLT-5 mediated mannose, fructose and AMG transport was weakly (μM potency) inhibited by SGLT-2 inhibitors. In summary, we have characterised SGLT-5 as a kidney mannose transporter. Further studies are warranted to explore the physiological role of SGLT-5.
Usha Panchapakesan; Kate Pegg; Simon Gross; Muralikrishna Gangadharan Komala; Harshini Mudaliar; Josephine Forbes; Carol Pollock; Amanda Mather
2013-01-01
Sodium/glucose cotransporter 2 (SGLT2) inhibitors are oral hypoglycemic agents used to treat patients with diabetes mellitus. SGLT2 inhibitors block reabsorption of filtered glucose by inhibiting SGLT2, the primary glucose transporter in the proximal tubular cell (PTC), leading to glycosuria and lowering of serum glucose. We examined the renoprotective effects of the SGLT2 inhibitor empagliflozin to determine whether blocking glucose entry into the kidney PTCs reduced the inflammatory and fib...
Directory of Open Access Journals (Sweden)
Yasong eLu
2014-12-01
Full Text Available In the kidney, glucose in glomerular filtrate is reabsorbed primarily by sodium-glucose cotransporters 1 (SGLT1 and 2 (SGLT2 along the proximal tubules. SGLT2 has been characterized as a high capacity, low affinity pathway responsible for reabsorption of the majority of filtered glucose in the early part of proximal tubules, and SGLT1 reabsorbs the residual glucose in the distal part. Inhibition of SGLT2 is a viable mechanism for removing glucose from the body and improving glycemic control in patients with diabetes. Despite demonstrating high levels (in excess of 80% of inhibition of glucose transport by SGLT2 in vitro, potent SGLT2 inhibitors, e.g., dapagliflozin and canagliflozin, inhibit renal glucose reabsorption by only 30-50% in clinical studies. Hypotheses for this apparent paradox are mostly focused on the compensatory effect of SGLT1. The paradox has been explained and the role of SGLT1 demonstrated in the mouse, but direct data in humans are lacking. To further explore the roles of SGLT1/2 in renal glucose reabsorption in humans, we developed a systems pharmacology model with emphasis on SGLT1/2 mediated glucose reabsorption and the effects of SGLT2 inhibition. The model was calibrated using robust clinical data in the absence or presence of dapagliflozin (DeFronzo et al. data (2013, and evaluated against clinical data from the literature (Mogensen, 1971;Wolf et al., 2009;Polidori et al., 2013. The model adequately described all four data sets. Simulations using the model clarified the operating characteristics of SGLT1/2 in humans in the healthy and diabetic state with or without SGLT2 inhibition. The modeling and simulations support our proposition that the apparent moderate, 30-50% inhibition of renal glucose reabsorption observed with potent SGLT2 inhibitors is a combined result of two physiological determinants: SGLT1 compensation and residual SGLT2 activity. This model will enable in silico inferences and predictions related to
Sodium glucose transporter 2 (SGLT2 inhibition and ketogenesis
Directory of Open Access Journals (Sweden)
Sanjay Kalra
2015-01-01
Full Text Available Sodium glucose transporter 2 (SGLT2 inhibitors are a recently developed class of drug that have been approved for use in type 2 diabetes. Their unique extra-pancreatic glucuretic mode of action has encouraged their usage in type 1 diabetes as well. At the same time, reports of pseudo ketoacidosis and ketoacidosis related to their use have been published. No clear mechanism for this phenomenon has been demonstrated so far. This communication delves into the biochemical effects of SGLT2 inhibition, discusses the utility of these drugs and proposes steps to maximize safe usage of the molecules.
Sodium glucose transporter 2 (SGLT2) inhibition and ketogenesis.
Kalra, Sanjay; Sahay, Rakesh; Gupta, Yashdeep
2015-01-01
Sodium glucose transporter 2 (SGLT2) inhibitors are a recently developed class of drug that have been approved for use in type 2 diabetes. Their unique extra-pancreatic glucuretic mode of action has encouraged their usage in type 1 diabetes as well. At the same time, reports of pseudo ketoacidosis and ketoacidosis related to their use have been published. No clear mechanism for this phenomenon has been demonstrated so far. This communication delves into the biochemical effects of SGLT2 inhibition, discusses the utility of these drugs and proposes steps to maximize safe usage of the molecules.
Bays, Harold
2013-01-01
Although hyperglycemia is a key therapeutic focus in the management of patients with type 2 diabetes mellitus (T2DM), many patients experience sub-optimal glycemic control. Current glucose-lowering agents involve the targeting of various body organs. Sodium glucose co-transporter type 2 (SGLT2) inhibitors target the kidney, reduce renal glucose reabsorption, and increase urinary glucose elimination, thus lowering glucose blood levels. This review examines some of the key efficacy and safety d...
Improved upper bounds on Kaluza-Klein gravity with current Solar System experiments and observations
Deng, Xue-Mei
2015-01-01
As an extension of previous works on classical tests of Kaluza-Klein (KK) gravity and as an attempt to find more stringent constraints on this theory, its effects on physical experiments and astronomical observations conducted in the Solar System are studied. We investigate the gravitational time delay at inferior conjunction caused by KK gravity, and use new Solar System ephemerides and the observation of \\textit{Cassini} to strengthen constraints on KK gravity by up to two orders of magnitude. These improved upper bounds mean that the fifth-dimensional space in the soliton case is a very flat extra dimension in the Solar System, even in the vicinity of the Sun.
Improved upper bounds on Kaluza-Klein gravity with current Solar System experiments and observations
Energy Technology Data Exchange (ETDEWEB)
Deng, Xue-Mei [Chinese Academy of Sciences, Purple Mountain Observatory, Nanjing (China); Xie, Yi [Nanjing University, School of Astronomy and Space Science, Nanjing (China); Shanghai Key Laboratory of Space Navigation and Position Techniques, Shanghai (China); Nanjing University, Ministry of Education, Key Laboratory of Modern Astronomy and Astrophysics, Nanjing (China)
2015-11-15
As an extension of previous works on classical tests of Kaluza-Klein (KK) gravity and as an attempt to find more stringent constraints on this theory, its effects on physical experiments and astronomical observations conducted in the Solar System are studied. We investigate the gravitational time delay at inferior conjunction caused by KK gravity, and use new Solar System ephemerides and the observation of Cassini to strengthen constraints on KK gravity by up to two orders of magnitude. These improved upper bounds mean that the fifth-dimensional space in the soliton case is a very flat extra dimension in the Solar System, even in the vicinity of the Sun. (orig.)
Why Do SGLT2 Inhibitors Inhibit Only 30–50% of Renal Glucose Reabsorption in Humans?
Liu, Jiwen; Lee, TaeWeon; DeFronzo, Ralph A.
2012-01-01
Sodium glucose cotransporter 2 (SGLT2) inhibition is a novel and promising treatment for diabetes under late-stage clinical development. It generally is accepted that SGLT2 mediates 90% of renal glucose reabsorption. However, SGLT2 inhibitors in clinical development inhibit only 30–50% of the filtered glucose load. Why are they unable to inhibit 90% of glucose reabsorption in humans? We will try to provide an explanation to this puzzle in this perspective analysis of the unique pharmacokineti...
Cellular distribution and regulation of intestinal SGLT1
Sá, Carla M.; Azevedo, Marisa; Lima, Cristóvão F; Wilson, Cristina Pereira
2011-01-01
Diabetes is achieving epidemic proportions in many countries. In addiction to high blood glucose it is associated with increased intestinal expression of the sodium-glucose cotransporter (SGLT1). This transporter is located in brush-border membrane (BBM) of the enterocytes and is responsible for transporting glucose and galactose from the intestinal lumen into the cytosol, using the inward Na+ gradient maintained by the basolateral Na+/K+-ATPase. Our previous results show that the adaptive re...
Phillips, D R; Devine, N K
1998-01-01
The electromagnetic interactions of a relativistic two-body bound state are formulated in three dimensions using an equal-time (ET) formalism. This involves a systematic reduction of four-dimensional dynamics to a three-dimensional form by integrating out the time components of relative momenta. A conserved electromagnetic current is developed for the ET formalism. It is shown that consistent truncations of the electromagnetic current and the $NN$ interaction kernel may be made, order-by-order in the coupling constants, such that appropriate Ward-Takahashi identities are satisfied. A meson-exchange model of the $NN$ interaction is used to calculate deuteron vertex functions. Calculations of electromagnetic form factors for elastic scattering of electrons by deuterium are performed using an impulse-approximation current. Negative-energy components of the deuteron's vertex function and retardation effects in the meson-exchange interaction are found to have only minor effects on the deuteron form factors.
Cai, Wenqing; Jiang, Linlin; Xie, Yafei; Liu, Yuqiang; Liu, Wei; Zhao, Guilong
2015-01-01
A brief history of the design of sodium-dependent glucose cotransporter 2 (SGLT2) inhibitors is reviewed. The design of O-glucoside SGLT2 inhibitors by structural modification of phlorizin, a naturally occurring O-glucoside, in the early stage was a process mainly driven by biology with anticipation of improving SGLT2/SGLT1 selectivity and increasing metabolic stability. Discovery of dapagliflozin, a pioneering C-glucoside SGLT2 inhibitor developed by Bristol-Myers Squibb, represents an important milestone in this history. In the second stage, the design of C-glycoside SGLT2 inhibitors by modifications of the aglycone and glucose moiety of dapagliflozin, an original structural template for almost all C-glycoside SGLT2 inhibitors, was mainly driven by synthetic organic chemistry due to the challenge of designing dapagliflozin derivatives that are patentable, biologically active and synthetically accessible. Structure-activity relationships (SAR) of the SGLT2 inhibitors are also discussed.
Analysis of efficacy of SGLT2 inhibitors using semi-mechanistic model
Directory of Open Access Journals (Sweden)
Oleg eDemin Jr
2014-10-01
Full Text Available Renal sodium-dependent glucose co-transporter 2 (SGLT2 is one of the most promising targets for the treatment of type 2 diabetes. Two SGLT2 inhibitors, dapagliflozin and canagliflozin, have already been approved for use in USA and Europe; several additional compounds are also being developed for this purpose. Based on the in vitro IC50 values and plasma concentration of dapagliflozin measured in clinical trials, the marketed dosage of the drug was expected to almost completely inhibit SGLT2 function and reduce glucose reabsorption by 90%. However, the administration of dapagliflozin resulted in only 30–50% inhibition of reabsorption. This study was aimed at investigating the mechanism underlying the discrepancy between the expected and observed levels of glucose reabsorption. To this end, systems pharmacology models were developed to analyze the time profile of dapagliflozin, canagliflozin, ipragliflozin, empagliflozin, and tofogliflozin in the plasma and urine; their filtration and active secretion from the blood to the renal proximal tubules; reverse reabsorption; urinary excretion; and their inhibitory effect on SGLT2. The model shows that concentration levels of tofogliflozin, ipragliflozin, and empagliflozin are higher than levels of other inhibitors following administration of marketed SGLT2 inhibitors at labeled doses and non-marketed SGLT2 inhibitors at maximal doses (approved for phase 2/3 studies. All the compounds exhibited almost 100% inhibition of SGLT2. Based on the results of our model, two explanations for the observed low efficacy of SGLT2 inhibitors were supported: 1 the site of action of SGLT2 inhibitors is not in the lumen of the kidney’s proximal tubules, but elsewhere (e.g., the kidneys proximal tubule cells; and 2 there are other transporters that could facilitate glucose reabsorption under the conditions of SGLT2 inhibition (e.g., other transporters of SGLT family.
Directory of Open Access Journals (Sweden)
Usha Panchapakesan
Full Text Available Sodium/glucose cotransporter 2 (SGLT2 inhibitors are oral hypoglycemic agents used to treat patients with diabetes mellitus. SGLT2 inhibitors block reabsorption of filtered glucose by inhibiting SGLT2, the primary glucose transporter in the proximal tubular cell (PTC, leading to glycosuria and lowering of serum glucose. We examined the renoprotective effects of the SGLT2 inhibitor empagliflozin to determine whether blocking glucose entry into the kidney PTCs reduced the inflammatory and fibrotic responses of the cell to high glucose. We used an in vitro model of human PTCs. HK2 cells (human kidney PTC line were exposed to control 5 mM, high glucose (HG 30 mM or the profibrotic cytokine transforming growth factor beta (TGFβ1; 0.5 ng/ml in the presence and absence of empagliflozin for up to 72 h. SGLT1 and 2 expression and various inflammatory/fibrotic markers were assessed. A chromatin immunoprecipitation assay was used to determine the binding of phosphorylated smad3 to the promoter region of the SGLT2 gene. Our data showed that TGFβ1 but not HG increased SGLT2 expression and this occurred via phosphorylated smad3. HG induced expression of Toll-like receptor-4, increased nuclear deoxyribonucleic acid binding for nuclear factor kappa B (NF-κB and activator protein 1, induced collagen IV expression as well as interleukin-6 secretion all of which were attenuated with empagliflozin. Empagliflozin did not reduce high mobility group box protein 1 induced NF-κB suggesting that its effect is specifically related to a reduction in glycotoxicity. SGLT1 and GLUT2 expression was not significantly altered with HG or empagliflozin. In conclusion, empagliflozin reduces HG induced inflammatory and fibrotic markers by blocking glucose transport and did not induce a compensatory increase in SGLT1/GLUT2 expression. Although HG itself does not regulate SGLT2 expression in our model, TGFβ increases SGLT2 expression through phosphorylated smad3.
Isotonic transport by the Na+-glucose cotransporter SGLT1 from humans and rabbit
DEFF Research Database (Denmark)
Zeuthen, T; Meinild, A K; Loo, D D;
2001-01-01
water transport was divided about equally between cotransport, osmosis across the SGLT1 and osmosis across the native oocyte membrane. 6. Coexpression of AQP1 with the SGLT1 increased the water permeability more than 10-fold and steady state isotonic transport was achieved after less than 2 s of sugar...
MAP17 and SGLT1 protein expression levels as prognostic markers for cervical tumor patient survival.
Directory of Open Access Journals (Sweden)
Marco Perez
Full Text Available MAP17 is a membrane-associated protein that is overexpressed in human tumors. Because the expression of MAP17 increases reactive oxygen species (ROS generation through SGLT1 in cancer cells, in the present work, we investigated whether MAP17 and/or SGLT1 might be markers for the activity of treatments involving oxidative stress, such as cisplatin or radiotherapy. First, we confirmed transcriptional alterations in genes involved in the oxidative stress induced by MAP17 expression in HeLa cervical tumor cells and found that Hela cells expressing MAP17 were more sensitive to therapies that induce ROS than were parental cells. Furthermore, MAP17 increased glucose uptake through SGLT receptors. We then analyzed MAP17 and SGLT1 expression levels in cervical tumors treated with cisplatin plus radiotherapy and correlated the expression levels with patient survival. MAP17 and SGLT1 were expressed in approximately 70% and 50% of cervical tumors of different types, respectively, but they were not expressed in adenoma tumors. Furthermore, there was a significant correlation between MAP17 and SGLT1 expression levels. High levels of either MAP17 or SGLT1 correlated with improved patient survival after treatment. However, the patients with high levels of both MAP17 and SGLT1 survived through the end of this study. Therefore, the combination of high MAP17 and SGLT1 levels is a marker for good prognosis in patients with cervical tumors after cisplatin plus radiotherapy treatment. These results also suggest that the use of MAP17 and SGLT1 markers may identify patients who are likely to exhibit a better response to treatments that boost oxidative stress in other cancer types.
MAP17 Is a Necessary Activator of Renal Na+/Glucose Cotransporter SGLT2.
Coady, Michael J; El Tarazi, Abdulah; Santer, René; Bissonnette, Pierre; Sasseville, Louis J; Calado, Joaquim; Lussier, Yoann; Dumayne, Christopher; Bichet, Daniel G; Lapointe, Jean-Yves
2017-01-01
The renal proximal tubule reabsorbs 90% of the filtered glucose load through the Na(+)-coupled glucose transporter SGLT2, and specific inhibitors of SGLT2 are now available to patients with diabetes to increase urinary glucose excretion. Using expression cloning, we identified an accessory protein, 17 kDa membrane-associated protein (MAP17), that increased SGLT2 activity in RNA-injected Xenopus oocytes by two orders of magnitude. Significant stimulation of SGLT2 activity also occurred in opossum kidney cells cotransfected with SGLT2 and MAP17. Notably, transfection with MAP17 did not change the quantity of SGLT2 protein at the cell surface in either cell type. To confirm the physiologic relevance of the MAP17-SGLT2 interaction, we studied a cohort of 60 individuals with familial renal glucosuria. One patient without any identifiable mutation in the SGLT2 coding gene (SLC5A2) displayed homozygosity for a splicing mutation (c.176+1G>A) in the MAP17 coding gene (PDZK1IP1). In the proximal tubule and in other tissues, MAP17 is known to interact with PDZK1, a scaffolding protein linked to other transporters, including Na(+)/H(+) exchanger 3, and to signaling pathways, such as the A-kinase anchor protein 2/protein kinase A pathway. Thus, these results provide the basis for a more thorough characterization of SGLT2 which would include the possible effects of its inhibition on colocalized renal transporters. Copyright © 2016 by the American Society of Nephrology.
SGLT1-mediated transport in Caco-2 cells is highly dependent on cell bank origin
DEFF Research Database (Denmark)
Steffansen, B; Pedersen, Maria; Laghmoch, A M
2017-01-01
The Caco-2 cell line is a well-established in vitro model for studying transport phenomena for prediction of intestinal nutrient and drug absorption. However, for substances depending on transporters such predictions are complicated due to variable transporter expression and limited knowledge about...... permeability (PSGLT1). Here, the objective was to characterize and compare SGLT1-mediated uptake in Caco-2 cells obtained from different cell banks. SGLT1-mediated uptake of the standard SGLT1 substrate, α-MDG, in Caco-2 cells was shown to be highly dependent on cell bank origin. The most robust and reliable...
Sodium-glucose cotransporter 2 (SGLT-2) inhibitors for patients with Type 2 diabetes
DEFF Research Database (Denmark)
Røder, Michael Einar; Storgaard, Heidi; Rungby, Jørgen;
2016-01-01
problem. Extremely rare cases of ketoacidosis are reported, mostly in patients with Type 1 diabetes. One SGLT-2i, empagliflozin, has been shown to reduce cardiovascular mortality and progression of kidney disease in patients with Type 2 diabetes and cardiovascular disease. Outcome trials for other SGLT-2i......The sodium-glucose cotransporter 2 inhibitor (SGLT-2i)-class is efficacious as monotherapy and as add-on therapy with an expected lowering of the glycated haemoglobin (HbA1c) concentration of approximately 7 mmol/mol. Side effects relate to the mode of action, genital infections are the main...... are pending. SGLT-2i are now in guidelines as a possible second-line therapy or in case of metformin intolerance....
The role of SGLT1 and GLUT2 in intestinal glucose transport and sensing.
Directory of Open Access Journals (Sweden)
Pia V Röder
Full Text Available Intestinal glucose absorption is mediated by SGLT1 whereas GLUT2 is considered to provide basolateral exit. Recently, it was proposed that GLUT2 can be recruited into the apical membrane after a high luminal glucose bolus allowing bulk absorption of glucose by facilitated diffusion. Moreover, SGLT1 and GLUT2 are suggested to play an important role in intestinal glucose sensing and incretin secretion. In mice that lack either SGLT1 or GLUT2 we re-assessed the role of these transporters in intestinal glucose uptake after radiotracer glucose gavage and performed Western blot analysis for transporter abundance in apical membrane fractions in a comparative approach. Moreover, we examined the contribution of these transporters to glucose-induced changes in plasma GIP, GLP-1 and insulin levels. In mice lacking SGLT1, tissue retention of tracer glucose was drastically reduced throughout the entire small intestine whereas GLUT2-deficient animals exhibited higher tracer contents in tissue samples than wild type animals. Deletion of SGLT1 resulted also in reduced blood glucose elevations and abolished GIP and GLP-1 secretion in response to glucose. In mice lacking GLUT2, glucose-induced insulin but not incretin secretion was impaired. Western blot analysis revealed unchanged protein levels of SGLT1 after glucose gavage. GLUT2 detected in apical membrane fractions mainly resulted from contamination with basolateral membranes but did not change in density after glucose administration. SGLT1 is unequivocally the prime intestinal glucose transporter even at high luminal glucose concentrations. Moreover, SGLT1 mediates glucose-induced incretin secretion. Our studies do not provide evidence for GLUT2 playing any role in either apical glucose influx or incretin secretion.
Carcinogenicity in rats of the SGLT2 inhibitor canagliflozin.
De Jonghe, Sandra; Proctor, Jim; Vinken, Petra; Feyen, Bianca; Wynant, Inneke; Marien, Dirk; Geys, Helena; Mamidi, Rao N V S; Johnson, Mark D
2014-12-05
The carcinogenicity potential of canagliflozin, an inhibitor of SGLT2, was evaluated in a 2-year rat study (10, 30, and 100 mg/kg). Rats showed an increase in pheochromocytomas, renal tubular tumors, and testicular Leydig cell tumors. Systemic exposure multiples at the highest dose relative to the maximum clinical dose were 12- to 21-fold. Pheochromocytomas and renal tubular tumors were noted in both sexes at 100 mg/kg. Leydig cell tumors were observed in males in all dose groups and were associated with increased luteinizing hormone levels. Hyperplasia was increased in the adrenal medulla at 100 mg/kg, but only a limited increase in simple tubular hyperplasia was observed in the kidney of males at 100 mg/kg. Hyperostosis occurred and was accompanied by substantial effects on calcium metabolism, including increased urinary calcium excretion and decreased levels of calcium regulating hormones (1,25-dihydroxyvitamin D and parathyroid hormone). A separate study with radiolabeled calcium confirmed that increased urinary calcium excretion was mediated via increased calcium absorption from the gastrointestinal tract. It was hypothesized that, at high doses, canagliflozin might have inhibited glucose absorption in the intestine via SGLT1 inhibition that resulted in glucose malabsorption, which increased calcium absorption by stimulating colonic glucose fermentation and reducing intestinal pH. Pheochromocytomas and adrenal medullary hyperplasia were attributed to altered calcium homeostasis, which have a known relationship in the rat. In conclusion, Leydig cell tumors were associated with increased luteinizing hormone levels and pheochromocytomas were most likely related to glucose malabsorption and altered calcium homeostasis. Renal tubular tumors may also have been linked to glucose malabsorption. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.
Vallon, Volker; Rose, Michael; Gerasimova, Maria; Satriano, Joseph; Platt, Kenneth A.; Koepsell, Hermann; Cunard, Robyn; Sharma, Kumar; Thomson, Scott C.; Rieg, Timo
2012-01-01
The Na-glucose cotransporter SGLT2 mediates high-capacity glucose uptake in the early proximal tubule and SGLT2 inhibitors are developed as new antidiabetic drugs. We used gene-targeted Sglt2 knockout (Sglt2−/−) mice to elucidate the contribution of SGLT2 to blood glucose control, glomerular hyperfiltration, kidney growth, and markers of renal growth and injury at 5 wk and 4.5 mo after induction of low-dose streptozotocin (STZ) diabetes. The absence of SGLT2 did not affect renal mRNA expressi...
Nagata, Takumi; Suzuki, Masayuki; Fukazawa, Masanori; Honda, Kiyofumi; Yamane, Mizuki; Yoshida, Ayae; Azabu, Hiroko; Kitamura, Hidekazu; Toyota, Naoto; Suzuki, Yoshiyuki; Kawabe, Yoshiki
2014-06-15
Sodium-glucose cotransporter 2 (SGLT2) inhibitors showed a glucose lowering effect in type 2 diabetes patients through inducing renal glucose excretion. Detailed analysis of the mechanism of the glucosuric effect of SGLT2 inhibition, however, has been hampered by limitations of clinical study. Here, we investigated the mechanism of urinary glucose excretion using nonhuman primates with SGLT inhibitors tofogliflozin and phlorizin, both in vitro and in vivo. In cells overexpressing cynomolgus monkey SGLT2 (cSGLT2), both tofogliflozin and phlorizin competitively inhibited uptake of the substrate (α-methyl-d-glucopyranoside; AMG). Tofogliflozin was found to be a selective cSGLT2 inhibitor, inhibiting cSGLT2 more strongly than did phlorizin, with selectivity toward cSGLT2 1,000 times that toward cSGLT1; phlorizin was found to be a nonselective cSGLT1/2 inhibitor. In a glucose titration study in cynomolgus monkeys under conditions of controlled plasma drug concentration, both tofogliflozin and phlorizin increased fractional excretion of glucose (FEG) by up to 50% under hyperglycemic conditions. By fitting the titration curve using a newly introduced method that avoids variability in estimating the threshold of renal glucose excretion, we found that tofogliflozin and phlorizin lowered the threshold and extended the splay in a dose-dependent manner without significantly affecting the tubular transport maximum for glucose (TmG). Our results demonstrate the contribution of SGLT2 to renal glucose reabsorption (RGR) in cynomolgus monkeys and demonstrate that competitive inhibition of cSGLT2 exerts a glucosuric effect by mainly extending splay and lowering threshold without affecting TmG.
Guo, Cheng; Hu, Min; DeOrazio, Russell J; Usyatinsky, Alexander; Fitzpatrick, Kevin; Zhang, Zhenjun; Maeng, Jun-Ho; Kitchen, Douglas B; Tom, Susan; Luche, Michele; Khmelnitsky, Yuri; Mhyre, Andrew J; Guzzo, Peter R; Liu, Shuang
2014-07-01
The sodium glucose co-transporter 2 (SGLT2) has received considerable attention in recent years as a target for the treatment of type 2 diabetes mellitus. This report describes the design, synthesis and structure-activity relationship (SAR) of C-glycosides with benzyltriazolopyridinone and phenylhydantoin as the aglycone moieties as novel SGLT2 inhibitors. Compounds 5p and 33b demonstrated high potency in inhibiting SGLT2 and high selectivity against SGLT1. The in vitro ADMET properties of these compounds will also be discussed. Copyright © 2014 Elsevier Ltd. All rights reserved.
Scheen, André J
2015-07-01
Inhibitors of sodium-glucose cotransporters type 2 (SGLT2) are proposed as a novel approach for the management of type 2 diabetes mellitus. SGLT2 cotransporters are responsible for reabsorption of 90 % of the glucose filtered by the kidney. The glucuretic effect resulting from SGLT2 inhibition contributes to reduce hyperglycaemia and also assists weight loss and blood pressure reduction. Several SGLT2 inhibitors are already available in many countries (dapagliflozin, canagliflozin, empagliflozin) and in Japan (ipragliflozin, tofogliflozin). These SGLT2 inhibitors share similar pharmacokinetic characteristics with a rapid oral absorption, a long elimination half-life allowing once-daily administration, an extensive hepatic metabolism mainly via glucuronidation to inactive metabolites and a low renal elimination as a parent drug. Pharmacokinetic parameters are slightly altered in the case of chronic kidney disease (CKD). While no dose adjustment is required in the case of mild CKD, SGLT2 inhibitors may not be used or only at a lower daily dose in patients with moderate CKD. Furthermore, the pharmacodynamic response to SGLT2 inhibitors as assessed by urinary glucose excretion declines with increasing severity of renal impairment as assessed by a reduction in the estimated glomerular filtration rate. Nevertheless, the glucose-lowering efficacy and safety of SGLT2 inhibitors are almost comparable in patients with mild CKD as in patients with normal kidney function. In patients with moderate CKD, the efficacy tends to be dampened and safety concerns may occur. In patients with severe CKD, the use of SGLT2 inhibitors is contraindicated. Thus, prescribing information should be consulted regarding dosage adjustments or restrictions in the case of renal dysfunction for each SGLT2 inhibitor. The clinical impact of SGLT2 inhibitors on renal function and their potential to influence the course of diabetic nephropathy deserve attention because of preliminary favourable results
Miller, Eden M
2017-02-01
The focus on the kidney as a therapeutic target for the treatment of type 2 diabetes mellitus (T2DM) has led to the development of the sodium-glucose cotransporter-2 (SGLT-2) inhibitors, of which 3 are available in the United States. This article addresses the implications for SGLT-2 inhibition in the treatment of T2DM.
A Review on the Relationship between SGLT2 Inhibitors and Cancer
Directory of Open Access Journals (Sweden)
Hao-Wen Lin
2014-01-01
Full Text Available Risk of increasing breast and bladder cancer remains a safety issue of SGLT2 (sodium glucose cotransporter type 2 inhibitors, a novel class of antidiabetic agent. We reviewed related papers published before January 29, 2014, through Pubmed search. Dapagliflozin and canagliflozin are the first two approved SGLT2 inhibitors for diabetes therapy. Although preclinical animal toxicology did not suggest a cancer risk of dapagliflozin and overall tumor did not increase, excess numbers of female breast cancer and male bladder cancer were noted in preclinical trials (without statistical significance. This concern of cancer risk hindered its approval by the US FDA in January, 2012. New clinical data suggested that the imbalance of bladder and breast cancer might be due to early diagnosis rather than a real increase of cancer incidence. No increased risk of overall bladder or breast cancer was noted for canagliflozin. Therefore, the imbalance observed with dapagliflozin treatment should not be considered as a class effect of SGLT2 inhibitors and the relationship with cancer for each specific SGLT2 inhibitor should be examined individually. Relationship between SGLT2 inhibition and cancer formation is still inconclusive and studies with larger sample size, longer exposure duration, and different ethnicities are warranted.
SGLT-2 Inhibitors: Is There a Role in Type 1 Diabetes Mellitus Management?
Ahmed-Sarwar, Nabila; Nagel, Angela K; Leistman, Samantha; Heacock, Kevin
2017-09-01
The purpose of this review is to identify and evaluate disease management of patients with type 1 diabetes mellitus (T1DM) who were treated with a sodium-glucose cotransporter 2 (SGLT-2) inhibitor as an adjunct to insulin therapy. A PubMed (1969 to March 2017) and Ovid (1946 to March 2017) search was performed for articles published utilizing the following MESH terms: canagliflozin, empagliflozin, dapagliflozin, type 1 diabetes mellitus, insulin dependent diabetes, insulin, sodium-glucose transporter 2. There were no limitations placed on publication type. All English-language articles were evaluated for association of SGLT-2 inhibitors and type 1 diabetes. Further studies were identified by review of pertinent manuscript bibliographies. All 3 SGLT-2 inhibitors, when combined with insulin, resulted in an overall reduction of hemoglobin A1C (up to 0.49%), lower total daily insulin doses, and a reduction in weight (up to 2.7 kg). The combination therapy of insulin and SGLT-2 inhibitors also resulted in a lower incidence of hypoglycemia. Study duration varied from 2 to 18 weeks. A review of the identified literature indicated that there is a potential role for the combination of SGLT-2 inhibitors with insulin in T1DM for improving glycemic control without increasing the risk of hypoglycemia. The short duration and small sample sizes limit the ability to fully evaluate the incidences of diabetic ketoacidosis and urogenital infections. The risks associated with this combination of medications require further evaluation.
Sapaev, Usman; Husakou, Anton; Herrmann, Joachim
2013-10-21
We study numerically low-order harmonic generation in noble gases pumped by intense femtosecond laser pulses in the tunneling ionization regime. We analyze the influence of the phase-mismatching on this process, caused by the generated plasma, and study in dependence on the pump intensity the origin of harmonic generation arising either from the bound-electron nonlinearity or the tunnel-ionization current. It is shown that in argon the optimum pump intensity of about 100 TW/cm² leads to the maximum efficiency, where the main contribution to low-order harmonics originates from the bound-electron third and fifth order susceptibilities, while for intensities higher than 300 TW/cm² the tunnel-ionization current plays the dominant role. Besides, we predict that VUV pulses at 133 nm can be generated with relatively high efficiency of about 1.5 × 10⁻³ by 400 nm pump pulses.
Sapaev, U; Herrmann, J
2013-01-01
We study numerically low-order harmonic generation in noble gases pumped by intense femtosecond laser pulses in the tunneling ionization regime. We analyze the influence of the phase-mismatching on this process, caused by the generated plasma, and study in dependence on the pump intensity the origin of harmonic generation arising either from the bound-electron nonlinearity or the tunnel-ionization current. It is shown that in argon the optimum pump intensity of about 100 TW/cm$^2$ leads to the maximum efficiency, where the main contribution to low-order harmonics originates from the bound-electron third and fifth order susceptibilities, while for intensities higher than 300 TW/cm$^2$ the tunnel-ionization current plays the dominant role. Besides, we predict that VUV pulses at 133 nm can be generated with relatively high efficiency of about $1.5\\times10^{-3}$ by 400 nm pump pulses.
Molecular analysis of the SGLT2 gene in patients with renal glucosuria
DEFF Research Database (Denmark)
Santer, René; Kinner, Martina; Lassen, Christoph L.
2003-01-01
heterozygous for an SGLT2 mutation resulting in glucosuria in the range of 14.6 to 202 g/1.73 m(2)/d (81 - 1120 mmol/1.73 m(2)/d). Some, but not all, of their heterozygous family members had an increased glucose excretion of up to 4.4 g/1.73 m(2)/d (24 mmol/1.73 m(2)/d). Likewise, in index cases...... with glucosuria below 10 g/1.73 m(2)/d (55 mmol/1.73 m(2)/d) an SGLT2 mutation, if present, was always detected in the heterozygous state. We conclude that SGLT2 plays an important role in renal tubular glucose reabsorption. Inheritance of renal glucosuria shows characteristics of a codominant trait with variable...
Determination of the Na(+)/glucose cotransporter (SGLT1) turnover rate using the ion-trap technique.
Longpré, Jean-Philippe; Lapointe, Jean-Yves
2011-01-05
The Na(+)/glucose cotransporter (SGLT1) is a membrane protein that couples the transport of two Na(+) ions and one glucose molecule using the so-called alternating access mechanism. According to this principle, each cotransporter molecule can adopt either of two main conformations: one with the binding sites accessible to the extracellular solution and one with the binding sites facing the intracellular solution. The turnover rate (TOR) is the number of complete cycles that each protein performs per second. Determination of the TOR has important consequences for investigation of the cotransport mechanism, as none of the rate constants involved in mediating transport in a given direction (conformational changes and binding and unbinding reactions) can be slower than the TOR measured under the same conditions. In addition, the TOR can be used to estimate the number of cotransporter molecules involved in generating a given ensemble activity. In this study, we obtain an independent estimation of the TOR for human SGLT1 expressed in Xenopus laevis oocytes applying the ion-trap technique. This approach detects the quantity of ions released in or taken up from the restricted space existing between the oocyte plasma membrane and the tip of a large ion-selective electrode. Taking advantage of the fact that hSGLT1 in the absence of Na(+) can cotransport glucose with protons, we used a pH electrode to determine a TOR of 8.00 ± 1.3 s⁻¹ in the presence of 35 mM α-methyl-glucose at -150 mV (pH 5.5). For the same group of oocytes, a TOR of 13.3 ± 2.4 s⁻¹ was estimated under near-V(max) conditions, i.e., in the presence of 90 mM Na(+) and 5 mM α-methyl-glucose. Under these circumstances, the average cotransport current was -1.08 ± 0.61 μA (n = 14), and this activity was generated by an average of 3.6 ± 0.7 × 10¹¹ cotransporter molecules/oocyte. Copyright © 2011 Biophysical Society. Published by Elsevier Inc. All rights reserved.
Determination of the Na+/Glucose Cotransporter (SGLT1) Turnover Rate Using the Ion-Trap Technique
Longpré, Jean-Philippe; Lapointe, Jean-Yves
2011-01-01
The Na+/glucose cotransporter (SGLT1) is a membrane protein that couples the transport of two Na+ ions and one glucose molecule using the so-called alternating access mechanism. According to this principle, each cotransporter molecule can adopt either of two main conformations: one with the binding sites accessible to the extracellular solution and one with the binding sites facing the intracellular solution. The turnover rate (TOR) is the number of complete cycles that each protein performs per second. Determination of the TOR has important consequences for investigation of the cotransport mechanism, as none of the rate constants involved in mediating transport in a given direction (conformational changes and binding and unbinding reactions) can be slower than the TOR measured under the same conditions. In addition, the TOR can be used to estimate the number of cotransporter molecules involved in generating a given ensemble activity. In this study, we obtain an independent estimation of the TOR for human SGLT1 expressed in Xenopus laevis oocytes applying the ion-trap technique. This approach detects the quantity of ions released in or taken up from the restricted space existing between the oocyte plasma membrane and the tip of a large ion-selective electrode. Taking advantage of the fact that hSGLT1 in the absence of Na+ can cotransport glucose with protons, we used a pH electrode to determine a TOR of 8.00 ± 1.3 s−1 in the presence of 35 mM α-methyl-glucose at −150 mV (pH 5.5). For the same group of oocytes, a TOR of 13.3 ± 2.4 s−1 was estimated under near-Vmax conditions, i.e., in the presence of 90 mM Na+ and 5 mM α-methyl-glucose. Under these circumstances, the average cotransport current was −1.08 ± 0.61 μA (n = 14), and this activity was generated by an average of 3.6 ± 0.7 × 1011 cotransporter molecules/oocyte. PMID:21190656
Fukuzawa, Taku; Fukazawa, Masanori; Ueda, Otoya; Shimada, Hideaki; Kito, Aki; Kakefuda, Mami; Kawase, Yosuke; Wada, Naoko A.; Goto, Chisato; Fukushima, Naoshi; Jishage, Kou-ichi; Honda, Kiyofumi; King, George L.; Kawabe, Yoshiki
2013-01-01
Although excessive fructose intake is epidemiologically linked with dyslipidemia, obesity, and diabetes, the mechanisms regulating plasma fructose are not well known. Cells transfected with sodium/glucose cotransporter 5 (SGLT5), which is expressed exclusively in the kidney, transport fructose in vitro; however, the physiological role of this transporter in fructose metabolism remains unclear. To determine whether SGLT5 functions as a fructose transporter in vivo, we established a line of mice lacking the gene encoding SGLT5. Sodium-dependent fructose uptake disappeared in renal brush border membrane vesicles from SGLT5-deficient mice, and the increased urinary fructose in SGLT5-deficient mice indicated that SGLT5 was the major fructose reabsorption transporter in the kidney. From this, we hypothesized that urinary fructose excretion induced by SGLT5 deficiency would ameliorate fructose-induced hepatic steatosis. To test this hypothesis we compared SGLT5-deficient mice with wild-type mice under conditions of long-term fructose consumption. Paradoxically, however, fructose-induced hepatic steatosis was exacerbated in the SGLT5-deficient mice, and the massive urinary fructose excretion was accompanied by reduced levels of plasma triglycerides and epididymal fat but fasting hyperinsulinemia compared with fructose-fed wild-type mice. There was no difference in food consumption, water intake, or plasma fructose between the two types of mice. No compensatory effect by other transporters reportedly involved in fructose uptake in the liver and kidney were indicated at the mRNA level. These surprising findings indicated a previously unrecognized link through SGLT5 between renal fructose reabsorption and hepatic lipid metabolism. PMID:23451068
KATP channel as well as SGLT1 participates in GIP secretion in the diabetic state.
Ogata, Hidetada; Seino, Yusuke; Harada, Norio; Iida, Atsushi; Suzuki, Kazuyo; Izumoto, Takako; Ishikawa, Kota; Uenishi, Eita; Ozaki, Nobuaki; Hayashi, Yoshitaka; Miki, Takashi; Inagaki, Nobuya; Tsunekawa, Shin; Hamada, Yoji; Seino, Susumu; Oiso, Yutaka
2014-08-01
Glucose-dependent insulinotropic polypeptide (GIP), a gut hormone secreted from intestinal K-cells, potentiates insulin secretion. Both K-cells and pancreatic β-cells are glucose-responsive and equipped with a similar glucose-sensing apparatus that includes glucokinase and an ATP-sensitive K(+) (KATP) channel comprising KIR6.2 and sulfonylurea receptor 1. In absorptive epithelial cells and enteroendocrine cells, sodium glucose co-transporter 1 (SGLT1) is also known to play an important role in glucose absorption and glucose-induced incretin secretion. However, the glucose-sensing mechanism in K-cells is not fully understood. In this study, we examined the involvement of SGLT1 (SLC5A1) and the KATP channels in glucose sensing in GIP secretion in both normal and streptozotocin-induced diabetic mice. Glimepiride, a sulfonylurea, did not induce GIP secretion and pretreatment with diazoxide, a KATP channel activator, did not affect glucose-induced GIP secretion in the normal state. In mice lacking KATP channels (Kir6.2(-/-) mice), glucose-induced GIP secretion was enhanced compared with control (Kir6.2(+) (/) (+)) mice, but was completely blocked by the SGLT1 inhibitor phlorizin. In Kir6.2(-/-) mice, intestinal glucose absorption through SGLT1 was enhanced compared with that in Kir6.2(+) (/) (+) mice. On the other hand, glucose-induced GIP secretion was enhanced in the diabetic state in Kir6.2(+) (/) (+) mice. This GIP secretion was partially blocked by phlorizin, but was completely blocked by pretreatment with diazoxide in addition to phlorizin administration. These results demonstrate that glucose-induced GIP secretion depends primarily on SGLT1 in the normal state, whereas the KATP channel as well as SGLT1 is involved in GIP secretion in the diabetic state in vivo.
Sabolić, Ivan; Vrhovac, Ivana; Eror, Daniela Balen; Gerasimova, Maria; Rose, Michael; Breljak, Davorka; Ljubojević, Marija; Brzica, Hrvoje; Sebastiani, Anne; Thal, Serge C.; Sauvant, Christoph; Kipp, Helmut; Vallon, Volker; Koepsell, Hermann
2012-01-01
With a novel antibody against the rat Na+-d-glucose cotransporter SGLT2 (rSGLT2-Ab), which does not cross-react with rSGLT1 or rSGLT3, the ∼75-kDa rSGLT2 protein was localized to the brush-border membrane (BBM) of the renal proximal tubule S1 and S2 segments (S1 > S2) with female-dominant expression in adult rats, whereas rSglt2 mRNA expression was similar in both sexes. Castration of adult males increased the abundance of rSGLT2 protein; this increase was further enhanced by estradiol and pr...
Shigeno, Riyoko; Horie, Ichiro; Ando, Takao; Abiru, Norio; Kawakami, Atsushi
2016-06-01
A low-carbohydrate diet is effective to improve hyperglycemia via insulin-independent actions. We report here that a low-carbohydrate diet combined with an SGLT2 inhibitor was effective and safe to treat refractory hyperglycemia in the perioperative period in a type 2 diabetes patient complicated with a high titer of insulin antibodies.
Sapaev, U; Husakou, A.; Herrmann, J.
2013-01-01
We study numerically low-order harmonic generation in noble gases pumped by intense femtosecond laser pulses in the tunneling ionization regime. We analyze the influence of the phase-mismatching on this process, caused by the generated plasma, and study in dependence on the pump intensity the origin of harmonic generation arising either from the bound-electron nonlinearity or the tunnel-ionization current. It is shown that in argon the optimum pump intensity of about 100 TW/cm$^2$ leads to th...
Scheen, A J; Paquot, N
2014-12-01
Sodium-glucose cotransporter type 2 (SGLT-2) inhibitors (canagliflozin, dapagliflozin, empagliflozin) are new glucose-lowering agents that exert their therapeutic activity independently of insulin by facilitating glucose excretion through the kidneys. However, this simple renal mechanism that results in sustained glucose urinary loss leads to more complex indirect metabolic effects. First, by reduction of chronic hyperglycaemia and attenuation of glucose toxicity, SGLT-2 inhibitors can improve both insulin secretion by beta cells and peripheraltissue insulin sensitivity. In the case of canagliflozin, because of low-potency SGLT1 inhibition, a non-renal (intestinal) effect may also be considered, which may contribute to better control of postprandial hyperglycaemia, although this contribution remains to be better analyzed in humans. Second, chronic glucose loss most probably leads to compensatory mechanisms. One of them, although not well evidenced in humans, might involve an increase in energy intake, an effect that may limit weight loss in the long run. Another could be an increase in endogenous glucose production, most probably driven by increased glucagon secretion, which may somewhat attenuate the glucoselowering effect. Nevertheless, despite these compensatory mechanisms and most probably because of the positive effects of the reduction in glucotoxicity, SGLT-2 inhibitors exert clinically relevant glucose-lowering activity while promoting weight loss, a unique dual effect among oral antidiabetic agents. Furthermore, the combination of SGLT-2 inhibitors with other drugs that either have anorectic effects (such as incretin-based therapies) or reduce hepatic glucose output (like metformin) and, thus, may dampen these two compensatory mechanisms appears appealing for the management of type 2 diabetes mellitus. Copyright © 2014 Elsevier Masson SAS. All rights reserved.
Bound entanglement and entanglement bounds
Energy Technology Data Exchange (ETDEWEB)
Sauer, Simeon [Physikalisch-Astronomische Fakultaet, Friedrich-Schiller-Univesitaet Jena (Germany)]|[Physikalisches Institut, Albert-Ludwigs-Universitaet Freiburg, Hermann-Herder-Strasse 3, D-79104 Freiburg (Germany); Melo, Fernando de; Mintert, Florian; Buchleitner, Andreas [Physikalisches Institut, Albert-Ludwigs-Universitaet Freiburg, Hermann-Herder-Strasse 3, D-79104 Freiburg (Germany)]|[Max-Planck-Institut fuer Physik komplexer Systeme, Noethnitzer Str.38, D-01187 Dresden (Germany); Bae, Joonwoo [School of Computational Sciences, Korea Institute for Advanced Study, Seoul 130-012 (Korea); Hiesmayr, Beatrix [Faculty of Physics, University of Vienna, Boltzmanngasse 5, A-1090 Vienna (Austria)
2008-07-01
We investigate the separability of Bell-diagonal states of two qutrits. By using lower bounds to algebraically estimate concurrence, we find convex regions of bound entangled states. Some of these regions exactly coincide with the obtained results when employing optimal entanglement witnesses, what shows that the lower bound can serve as a precise detector of entanglement. Some hitherto unknown regions of bound entangled states were discovered with this approach, and delimited efficiently.
Directory of Open Access Journals (Sweden)
Huizhen Cai
2017-02-01
Full Text Available Lycium barbarum L. polysaccharide (LBP is prepared from Lycium barbarum L. (L. barbarum, which is a traditional Chinese medicine. LPB has been shown to have hypoglycemic effects. In order to gain some mechanistic insights on the hypoglycemic effects of LBP, we investigated the uptake of LBP and its effect on glucose absorption in the human intestinal epithelial cell line Caco2 cell. The uptake of LBP through Caco2 cell monolayer was time-dependent and was inhibited by phloridzin, a competitive inhibitor of SGLT-1. LPB decreased the absorption of glucose in Caco2 cell, and down-regulated the expression of SGLT-1. These results suggest that LBP might be transported across the human intestinal epithelium through SGLT-1 and it inhibits glucose uptake via down-regulating SGLT-1.
Saha, J P; Saha, Jyoti Prasad; Kundu, Anirban
2004-01-01
We perform a systematic reevaluation of the constraints on the flavor-changing neutral current (FCNC) parameters in R-parity conserving and R-parity violating supersymmetric models. As a typical process, we study the constraints coming from the measurements on the B0-\\bar{B0} system on the supersymmetric $\\delta^d_{13}$ parameters, as well as on the products of the lambda' type R-parity violating couplings. Present data allows us to put constraints on both the real and the imaginary parts of the relevant parameters.
Hong, Mengqi; Nie, Zhenyu; Chen, Zhengyue; Yu, Xiongwei; Bao, Beiyan
2016-05-25
Objective: To investigate the role of glucose transporter 1 (GLUT1) and sodium-glucose cotransporter 1 (SGLT1) in high glucose dialysate-induced peritoneal fibrosis. Methods: Thirty six male SD rats were randomly divided into 6 groups (6 in each):normal control group, sham operation group, peritoneal dialysis group (PD group), PD+phloretin group (PD+T group), PD+phlorizin group (PD+Z group), PD+phloretin+phlorizin group (PD+T+Z group). Rat model of uraemia was established using 5/6 nephrotomy, and 2.5% dextrose peritoneal dialysis solution was used in peritoneal dialysis. Peritoneal equilibration test was performed 24 h after dialysis to evaluate transport function of peritoneum in rats; HE staining was used to observe the morphology of peritoneal tissue; and immunohistochemistry was used to detect the expression of GLUT1, SGLT1, TGF-β1 and connective tissue growth factor (CTGF) in peritoneum. Human peritoneal microvascular endothelial cells (HPECs) were divided into 5 groups:normal control group, peritoneal dialysis group (PD group), PD+phloretin group (PD+T group), PD+phlorezin group (PD+Z group), and PD+phloretin+phlorezin group (PD+T+Z group). Real time PCR and Western blotting were used to detect mRNA and protein expressions of GLUT1, SGLT1, TGF-β1, CTGF in peritoneal membrane and HPECs. Results:In vivo, compared with sham operation group, rats in PD group had thickened peritoneum, higher ultrafiltration volume, and the mRNA and protein expressions of GLUT1, SGLT1, CTGF, TGF-β1 were significantly increased (all P<0.05); compared with PD group, thickened peritoneum was attenuated, and the mRNA and protein expressions of GLUT1, SGLT1, CTGF, TGF-β1 were significantly decreased in PD+T, PD+Z and PD+T+Z groups (all P<0.05). Pearson's correlation analysis showed that the expressions of GLUT1, SGLT1 in peritoneum were positively correlated with the expressions of TGF-β1 and CTGF (all P<0.05). In vitro, the mRNA and protein expressions of GLUT1, SGLT1, TGF-β1
Chino, Yukihiro; Samukawa, Yoshishige; Sakai, Soichi; Nakai, Yasuhiro; Yamaguchi, Jun-ichi; Nakanishi, Takeo; Tamai, Ikumi
2014-01-01
Sodium glucose cotransporter 2 (SGLT2) inhibitors have been reported to lower the serum uric acid (SUA) level. To elucidate the mechanism responsible for this reduction, SUA and the urinary excretion rate of uric acid (UEUA) were analysed after the oral administration of luseogliflozin, a SGLT2 inhibitor, to healthy subjects. After dosing, SUA decreased, and a negative correlation was observed between the SUA level and the UEUA, suggesting that SUA decreased as a result of the increase in the...
Taku Fukuzawa; Masanori Fukazawa; Otoya Ueda; Hideaki Shimada; Aki Kito; Mami Kakefuda; Yosuke Kawase; Naoko A Wada; Chisato Goto; Naoshi Fukushima; Kou-Ichi Jishage; Kiyofumi Honda; King, George L.; Yoshiki Kawabe
2013-01-01
Although excessive fructose intake is epidemiologically linked with dyslipidemia, obesity, and diabetes, the mechanisms regulating plasma fructose are not well known. Cells transfected with sodium/glucose cotransporter 5 (SGLT5), which is expressed exclusively in the kidney, transport fructose in vitro; however, the physiological role of this transporter in fructose metabolism remains unclear. To determine whether SGLT5 functions as a fructose transporter in vivo, we established a line of mic...
Bounding species distribution models
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Thomas J. STOHLGREN, Catherine S. JARNEVICH, Wayne E. ESAIAS,Jeffrey T. MORISETTE
2011-10-01
Full Text Available Species distribution models are increasing in popularity for mapping suitable habitat for species of management concern. Many investigators now recognize that extrapolations of these models with geographic information systems (GIS might be sensitive to the environmental bounds of the data used in their development, yet there is no recommended best practice for “clamping” model extrapolations. We relied on two commonly used modeling approaches: classification and regression tree (CART and maximum entropy (Maxent models, and we tested a simple alteration of the model extrapolations, bounding extrapolations to the maximum and minimum values of primary environmental predictors, to provide a more realistic map of suitable habitat of hybridized Africanized honey bees in the southwestern United States. Findings suggest that multiple models of bounding, and the most conservative bounding of species distribution models, like those presented here, should probably replace the unbounded or loosely bounded techniques currently used [Current Zoology 57 (5: 642–647, 2011].
Bounding Species Distribution Models
Stohlgren, Thomas J.; Jarnevich, Cahterine S.; Morisette, Jeffrey T.; Esaias, Wayne E.
2011-01-01
Species distribution models are increasing in popularity for mapping suitable habitat for species of management concern. Many investigators now recognize that extrapolations of these models with geographic information systems (GIS) might be sensitive to the environmental bounds of the data used in their development, yet there is no recommended best practice for "clamping" model extrapolations. We relied on two commonly used modeling approaches: classification and regression tree (CART) and maximum entropy (Maxent) models, and we tested a simple alteration of the model extrapolations, bounding extrapolations to the maximum and minimum values of primary environmental predictors, to provide a more realistic map of suitable habitat of hybridized Africanized honey bees in the southwestern United States. Findings suggest that multiple models of bounding, and the most conservative bounding of species distribution models, like those presented here, should probably replace the unbounded or loosely bounded techniques currently used [Current Zoology 57 (5): 642-647, 2011].
A Novel Therapeutic Agent for Type 2 Diabetes Mellitus: SGLT2 Inhibitor
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Chang Hee Jung
2014-08-01
Full Text Available Type 2 diabetes mellitus (T2DM is a complex endocrine and metabolic disorder, and a major public health problem that is rapidly increasing in prevalence. Although a wide range of pharmacotherapies for glycemic control is now available, management of T2DM remains complex and challenging. The kidneys contribute immensely to glucose homeostasis by reabsorbing glucose from the glomerular filtrate. Sodium-glucose cotransporter 2 (SGLT2 inhibitors, a new class of antidiabetic agents that inhibit glucose absorption from the kidney independent of insulin, offer a unique opportunity to improve the outcomes of patients with T2DM. In this review, we provide an overview of two globally-approved SGLT2 inhibitors, dapagliflozin and canagliflozin, and discuss their effects and safety. This information will help clinicians to decide whether these drugs will benefit their patients.
SGLT2 inhibition: a novel prospective strategy in treatment of diabetes mellitus.
Deshmukh, Aaishwarya B; Patel, Maharshi C; Mishra, Bharat
2013-01-01
The role of the kidney in glucose homeostasis and the potential of the kidney as a therapeutic target in type 2 diabetes is little appreciated. Hyperglycemia is an important pathogenic component in the development of microvascular and macrovascular complications in type 2 diabetes mellitus. Inhibition of renal tubular glucose re-absorption that leads to glycosuria has been proposed as a new mechanism to attain normoglycemia and thus prevent and diminish these complications, thus representing an innovative therapeutic strategy for the treatment of hyperglycemia and/or obesity in patients with type 1 or type 2 diabetes by enhancing glucose and energy loss through the urine. Sodium glucose co-transporter 2 (SGLT2) has a key role in re-absorption of glucose in kidney. Competitive inhibitors of SGLT2 have been discovered and a few of them have also been advanced in clinical trials for the treatment of diabetes.
QSAR studies on triazole derivatives as sglt inhibitors via CoMFA and CoMSIA
Zhi, Hui; Zheng, Junxia; Chang, Yiqun; Li, Qingguo; Liao, Guochao; Wang, Qi; Sun, Pinghua
2015-10-01
Forty-six sodium-dependent glucose cotransporters-2 (SGLT-2) inhibitors with hypoglycemic activity were selected to develop three-dimensional quantitative structure-activity relationship (3D-QSAR) using comparative molecular field analysis (CoMFA) and comparative molecular similarity indices analysis (CoMSIA) models. A training set of 39 compounds were used to build up the models, which were then evaluated by a series of internal and external cross-validation techniques. A test set of 7 compounds was used for the external validation. The CoMFA model predicted a q2 value of 0.792 and an r2 value of 0.985. The best CoMSIA model predicted a q2 value of 0.633 and an r2 value of 0.895 based on a combination of steric, electrostatic, hydrophobic and hydrogen-bond acceptor effects. The predictive correlation coefficients of CoMFA and CoMSIA models were 0.872 and 0.839, respectively. The analysis of the contour maps from each model provided insight into the structural requirements for the development of more active sglt inhibitors, and on the basis of the models 8 new sglt inhibitors were designed and predicted.
Sodium-glucose co-transporter 2 (SGLT2 inhibitors: a growing class of anti-diabetic agents
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Eva M Vivian
2014-12-01
Full Text Available Although several treatment options are available to reduce hyperglycemia, only about half of individuals with diagnosed diabetes mellitus (DM achieve recommended glycemic targets. New agents that reduce blood glucose concentrations by novel mechanisms and have acceptable safety profiles are needed to improve glycemic control and reduce the complications associated with type 2 diabetes mellitus (T2DM. The renal sodium-glucose co-transporter 2 (SGLT2 is responsible for reabsorption of most of the glucose filtered by the kidney. Inhibitors of SGLT2 lower blood glucose independent of the secretion and action of insulin by inhibiting renal reabsorption of glucose, thereby promoting the increased urinary excretion of excess glucose. Canagliflozin, dapagliflozin, and empagliflozin are SGLT2 inhibitors approved as treatments for T2DM in the United States, Europe, and other countries. Canagliflozin, dapagliflozin, and empagliflozin increase renal excretion of glucose and improve glycemic parameters in patients with T2DM when used as monotherapy or in combination with other antihyperglycemic agents. Treatment with SGLT2 inhibitors is associated with weight reduction, lowered blood pressure, and a low intrinsic propensity to cause hypoglycemia. Overall, canagliflozin, dapagliflozin, and empagliflozin are well tolerated. Cases of genital infections and, in some studies, urinary tract infections have been more frequent in canagliflozin-, dapagliflozin-, and empagliflozin-treated patients compared with those receiving placebo. Evidence from clinical trials suggests that SGLT2 inhibitors are a promising new treatment option for T2DM.
Singh, Awadhesh Kumar; Singh, Ritu
2017-06-01
Both sodium-glucose co-transporter-2 inhibitors (SGLT-2Is) and glucagon-like peptide-1 receptor agonists (GLP-1RAs) have been consistently found to lower blood glucose, body weight and systolic blood pressure (SBP) in patients with type 2 diabetes mellitus (T2DM). While all the SGLT-2Is inhibit glucose reabsorption by blocking SGLT-2 receptor in kidney, dose-dependently, the highest licensed dose of canagliflozin 300-mg has an additional ability to inhibit SGLT-1 receptor in intestine transiently, that may lead to additional inhibition of prandial glucose absorption, unlike other approved highly selective SGLT-2Is. Areas covered: An electronic search on studies with highest licensed dose of all approved SGLT-2Is and long-acting GLP-1RAs was made up to December 2016. We systemically reviewed the studies of canagliflozin 300-mg and compared its glucose, body weight and SBP lowering with other approved SGLT-2Is and GLP-1RAs in their highest approved doses. Expert commentary: From the available evidences, it appears that canagliflozin 300-mg may have the highest potential to improve gluco-metabolic profile in T2DM, amongst the SGLT-2Is class. While the highest approved dosage of GLP-1RAs lowered HbA1c better than canagliflozin 300-mg, weight and SBP lowering could be non-inferior or slightly better with the latter drug. Nonetheless, only head-to-head trial can conclusively answer these questions.
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Masato Furuhashi
Full Text Available Fatty acid-binding protein 4 (FABP4/A-FABP/aP2 is secreted from adipocytes in association with catecholamine-induced lipolysis, and elevated serum FABP4 level is associated with obesity, insulin resistance and atherosclerosis. Secreted FABP4 as a novel adipokine leads to insulin resistance via increased hepatic glucose production (HGP. Sodium-glucose cotransporter 2 (SGLT2 inhibitors decrease blood glucose level via increased urinary glucose excretion, though HGP is enhanced. Here we investigated whether canagliflozin, an SGLT2 inhibitor, modulates serum FABP4 level.Canagliflozin (100 mg/day was administered to type 2 diabetic patients (n = 39 for 12 weeks. Serum FABP4 level was measured before and after treatment.At baseline, serum FABP4 level was correlated with adiposity, renal dysfunction and noradrenaline level. Treatment with canagliflozin significantly decreased adiposity and levels of fasting glucose and HbA1c but increased average serum FABP4 level by 10.3% (18.0 ± 1.0 vs. 19.8 ± 1.2 ng/ml, P = 0.008, though elevation of FABP4 level after treatment was observed in 26 (66.7% out of 39 patients. Change in FABP4 level was positively correlated with change in levels of fasting glucose (r = 0.329, P = 0.044, HbA1c (r = 0.329, P = 0.044 and noradrenaline (r = 0.329, P = 0.041 but was not significantly correlated with change in adiposity or other variables.Canagliflozin paradoxically increases serum FABP4 level in some diabetic patients despite amelioration of glucose metabolism and adiposity reduction, possibly via induction of catecholamine-induced lipolysis in adipocytes. Increased FABP4 level by canagliflozin may undermine the improvement of glucose metabolism and might be a possible mechanism of increased HGP by inhibition of SGLT2.UMIN-CTR Clinical Trial UMIN000018151.
Furuhashi, Masato; Matsumoto, Megumi; Hiramitsu, Shinya; Omori, Akina; Tanaka, Marenao; Moniwa, Norihito; Yoshida, Hideaki; Ishii, Junnichi; Miura, Tetsuji
2016-01-01
Fatty acid-binding protein 4 (FABP4/A-FABP/aP2) is secreted from adipocytes in association with catecholamine-induced lipolysis, and elevated serum FABP4 level is associated with obesity, insulin resistance and atherosclerosis. Secreted FABP4 as a novel adipokine leads to insulin resistance via increased hepatic glucose production (HGP). Sodium-glucose cotransporter 2 (SGLT2) inhibitors decrease blood glucose level via increased urinary glucose excretion, though HGP is enhanced. Here we investigated whether canagliflozin, an SGLT2 inhibitor, modulates serum FABP4 level. Canagliflozin (100 mg/day) was administered to type 2 diabetic patients (n = 39) for 12 weeks. Serum FABP4 level was measured before and after treatment. At baseline, serum FABP4 level was correlated with adiposity, renal dysfunction and noradrenaline level. Treatment with canagliflozin significantly decreased adiposity and levels of fasting glucose and HbA1c but increased average serum FABP4 level by 10.3% (18.0 ± 1.0 vs. 19.8 ± 1.2 ng/ml, P = 0.008), though elevation of FABP4 level after treatment was observed in 26 (66.7%) out of 39 patients. Change in FABP4 level was positively correlated with change in levels of fasting glucose (r = 0.329, P = 0.044), HbA1c (r = 0.329, P = 0.044) and noradrenaline (r = 0.329, P = 0.041) but was not significantly correlated with change in adiposity or other variables. Canagliflozin paradoxically increases serum FABP4 level in some diabetic patients despite amelioration of glucose metabolism and adiposity reduction, possibly via induction of catecholamine-induced lipolysis in adipocytes. Increased FABP4 level by canagliflozin may undermine the improvement of glucose metabolism and might be a possible mechanism of increased HGP by inhibition of SGLT2. UMIN-CTR Clinical Trial UMIN000018151.
Hot Topics in Primary Care: Role of the Kidney and SGLT-2 Inhibition in Type 2 Diabetes Mellitus.
Miller, Kevin; Miller, Eden M
2015-12-01
SGLT-2 inhibitors provide a complementary mechanism of glucose lowering and can be used as monotherapy or in combination with other medications, including insulin. In addition to improved glycemic control, which generally is maintained over 2 years, SGLT-2 inhibitors provide reductions in body weight and systolic blood pressure. Increases in LDL-C and HDL-C also have been observed. A requirement for adequate renal function is a limitation in patients with CKD. A low incidence of hypoglycemia, ability to promote weight loss, and availability as an oral formulation diminish common barriers to glucose-lowering therapy.
Syntheses of isotope-labeled SGLT2 inhibitor canagliflozin (JNJ-28431754).
Lin, Ronghui; Hoerr, David C; Weaner, Larry E; Salter, Rhys
2017-08-18
Canagliflozin (Invokana, JNJ-28431754) is an orally bioavailable and selective SGLT2 (subtype 2 sodium-glucose transport protein) inhibitor approved for the treatment of type 2 diabetes. Herein, we report the synthesis of (13) C and (14) C-labeled canagliflozin. Stable isotope-labeled [(13) C6 ]canagliflozin was synthesized in 4 steps starting from [(13) C6 ]-labeled glucose. The [(14) C]-Labeled canagliflozin was synthesized by incorporation of [(14) C] into the benzylic position between the thiophene and benzene rings of the compound. Detailed synthesis of the isotope-labeled compounds is reported. Copyright © 2017 John Wiley & Sons, Ltd.
Sharma, Mukesh C.; Sharma, Smita
2014-01-01
A QSAR study on thiophenyl derivatives as SGLT2 inhibitors as potential antidiabetic agents was performed with thirty-three compounds. Comparison of the obtained results indicated the superiority of the genetic algorithm over the simulated annealing and stepwise forward-backward variable method for feature selection. The best 2D QSAR model showed satisfactory statistical parameters for the data set (r2 = 0.8499, q2 = 0.8267, and pred_r2 = 0.7729) with four descriptors describing the nature of substituent groups and the environment of the substitution site. Evaluation of the model implied that electron-rich substitution position improves the inhibitory activity. The good predictive 3D-QSAR models by k-nearest neighbor (kNN) method for molecular field analysis (MFA) have cross-validated coefficient q2 value of 0.7663 and predicted r2 value of 0.7386. The results have showed that thiophenyl groups are necessary for activity and halogen, bulky, and less bulky groups in thiophenyl nucleus enhanced the biological activity. These studies are promising for the development of novel SGLT2 inhibitor, which may have potent antidiabetic activity. PMID:25574393
Canagliflozin: A novel SGLT2 inhibitor for type 2 diabetes mellitus
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Shaveta Kaushal
2014-01-01
Full Text Available Diabetes Mellitus continues to be a major non- communicable disease with global burden of 366 million at present and projected to increase to 439 to 552 million by 2030, India being the hub of diabetes. Sodium glucose transporter 2 (SGLT2 inhibitors presents a new class of anti-diabetic drugs having an insulin-independent mechanism that offers a considerable advantage of increasing urinary glucose excretion without inducing hypoglycemia and promoting weight loss due to loss of 300 to 400kcal/day, Canagliflozin being the 1 st successful candidate of this group and became the first SGLT2 inhibitor to be FDA approved on March 29, 2013. In various clinical trials, it has shown promising results in controlling glycemia, causing weight loss, reducing systolic and diastolic BP and cardiovascular risk. There are some safety concerns associated with its use e.g. genital mycotic infections, increased urination, urinary tract infection and hyperkalemia, which need to be carefully addressed while using this drug.
Canagliflozin: A Novel SGLT2 Inhibitor for Type 2 Diabetes Mellitus
Kaushal, Shaveta; Singh, Harmanjit; Thangaraju, Pugazhenthan; Singh, Jasbir
2014-01-01
Diabetes Mellitus continues to be a major non- communicable disease with global burden of 366 million at present and projected to increase to 439 to 552 million by 2030, India being the hub of diabetes. Sodium glucose transporter 2 (SGLT2) inhibitors presents a new class of anti-diabetic drugs having an insulin-independent mechanism that offers a considerable advantage of increasing urinary glucose excretion without inducing hypoglycemia and promoting weight loss due to loss of 300 to 400kcal/day, Canagliflozin being the 1st successful candidate of this group and became the first SGLT2 inhibitor to be FDA approved on March 29, 2013. In various clinical trials, it has shown promising results in controlling glycemia, causing weight loss, reducing systolic and diastolic BP and cardiovascular risk. There are some safety concerns associated with its use e.g. genital mycotic infections, increased urination, urinary tract infection and hyperkalemia, which need to be carefully addressed while using this drug. PMID:24741548
Directory of Open Access Journals (Sweden)
Mukesh C. Sharma
2014-01-01
Full Text Available A QSAR study on thiophenyl derivatives as SGLT2 inhibitors as potential antidiabetic agents was performed with thirty-three compounds. Comparison of the obtained results indicated the superiority of the genetic algorithm over the simulated annealing and stepwise forward-backward variable method for feature selection. The best 2D QSAR model showed satisfactory statistical parameters for the data set (r2=0.8499, q2=0.8267, and pred_r2=0.7729 with four descriptors describing the nature of substituent groups and the environment of the substitution site. Evaluation of the model implied that electron-rich substitution position improves the inhibitory activity. The good predictive 3D-QSAR models by k-nearest neighbor (kNN method for molecular field analysis (MFA have cross-validated coefficient q2 value of 0.7663 and predicted r2 value of 0.7386. The results have showed that thiophenyl groups are necessary for activity and halogen, bulky, and less bulky groups in thiophenyl nucleus enhanced the biological activity. These studies are promising for the development of novel SGLT2 inhibitor, which may have potent antidiabetic activity.
Bounding species distribution models
Institute of Scientific and Technical Information of China (English)
Thomas J. STOHLGREN; Catherine S. JARNEVICH; Wayne E. ESAIAS; Jeffrey T. MORISETTE
2011-01-01
Species distribution models are increasing in popularity for mapping suitable habitat for species of management concern.Many investigators now recognize that extrapolations of these models with geographic information systems (GIS) might be sensitive to the environmental bounds of the data used in their development,yet there is no recommended best practice for “clamping” model extrapolations.We relied on two commonly used modeling approaches:classification and regression tree (CART) and maximum entropy (Maxent) models,and we tested a simple alteration of the model extrapolations,bounding extrapolations to the maximum and minimum values of primary environmental predictors,to provide a more realistic map of suitable habitat of hybridized Africanized honey bees in the southwestern United States.Findings suggest that multiple models of bounding,and the most conservative bounding of species distribution models,like those presented here,should probably replace the unbounded or loosely bounded techniques currently used [Current Zoology 57 (5):642-647,2011].
Seufert, Jochen
2015-01-01
Despite the availability of a great variety of medications, a significant proportion of people with type 2 diabetes mellitus (T2DM) are not able to achieve or maintain adequate glycemic control. Beyond improved glucose control, novel treatments would ideally provide a reduction of cardiovascular risk, with a favorable impact on excess weight, and a low intrinsic hypoglycemia risk, as well as a synergistic mechanism of action for broad combination therapy. With the development of sodium glucose cotransporter 2 (SGLT2) inhibitors, an antidiabetic pharmacologic option has recently become available that comes close to meeting these requirements. For the first time, SGLT2 inhibitors offer a therapeutic approach acting directly on the kidneys without requiring insulin secretion or action. Canagliflozin, dapagliflozin, and empagliflozin are the SGLT2 inhibitors approved to date. Taken once a day, these medications can be combined with all other antidiabetic medications including insulin, due to their insulin-independent mechanism of action, with only a minimal risk of hypoglycemia. SGLT2 inhibitors provide additional reductions in body weight and blood pressure due to the therapeutically induced excretion of glucose and sodium through the kidneys. These “concomitant effects” are particularly interesting with regard to the increased cardiovascular risk in T2DM. In many cases, T2DM treatment requires a multidimensional approach where the treatment goals have to be adapted to the individual patient. While there is a consensus on the use of metformin as a first-line drug therapy, various antidiabetics are used for treatment intensification. New mechanisms of action like that of SGLT2 inhibitors such as canagliflozin, which can be used both in early and late stages of diabetes, are a welcome addition to expand the treatment options for patients at every stage of T2DM. The efficacy and tolerability of canagliflozin have been tested in an extensive clinical trial program
Seufert, Jochen
2015-01-01
Despite the availability of a great variety of medications, a significant proportion of people with type 2 diabetes mellitus (T2DM) are not able to achieve or maintain adequate glycemic control. Beyond improved glucose control, novel treatments would ideally provide a reduction of cardiovascular risk, with a favorable impact on excess weight, and a low intrinsic hypoglycemia risk, as well as a synergistic mechanism of action for broad combination therapy. With the development of sodium glucose cotransporter 2 (SGLT2) inhibitors, an antidiabetic pharmacologic option has recently become available that comes close to meeting these requirements. For the first time, SGLT2 inhibitors offer a therapeutic approach acting directly on the kidneys without requiring insulin secretion or action. Canagliflozin, dapagliflozin, and empagliflozin are the SGLT2 inhibitors approved to date. Taken once a day, these medications can be combined with all other antidiabetic medications including insulin, due to their insulin-independent mechanism of action, with only a minimal risk of hypoglycemia. SGLT2 inhibitors provide additional reductions in body weight and blood pressure due to the therapeutically induced excretion of glucose and sodium through the kidneys. These "concomitant effects" are particularly interesting with regard to the increased cardiovascular risk in T2DM. In many cases, T2DM treatment requires a multidimensional approach where the treatment goals have to be adapted to the individual patient. While there is a consensus on the use of metformin as a first-line drug therapy, various antidiabetics are used for treatment intensification. New mechanisms of action like that of SGLT2 inhibitors such as canagliflozin, which can be used both in early and late stages of diabetes, are a welcome addition to expand the treatment options for patients at every stage of T2DM. The efficacy and tolerability of canagliflozin have been tested in an extensive clinical trial program
Positive Root Bounds and Root Separation Bounds
Herman, Aaron Paul
In this thesis, we study two classes of bounds on the roots of a polynomial (or polynomial system). A positive root bound of a polynomial is an upper bound on the largest positive root. A root separation bound of a polynomial is a lower bound on the distance between the roots. Both classes of bounds are fundamental tools in computer algebra and computational real algebraic geometry, with numerous applications. In the first part of the thesis, we study the quality of positive root bounds. Higher quality means that the relative over-estimation (the ratio of the bound and the largest positive root) is smaller. We find that all known positive root bounds can be arbitrarily bad. We then show that a particular positive root bound is tight for certain important classes of polynomials. In the remainder of the thesis, we turn to root separation bounds. We observe that known root separation bounds are usually very pessimistic. To our surprise, we also find that known root separation bounds are not compatible with the geometry of the roots (unlike positive root bounds). This motivates us to derive new root separation bounds. In the second part of this thesis, we derive a new root separation for univariate polynomials by transforming a known bound into a new improved bound. In the third part of this thesis, we use a similar strategy to derive a new improved root separation bound for polynomial systems.
SGLT-2 inhibitors and their potential in the treatment of diabetes
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Rosenwasser RF
2013-11-01
Full Text Available Rebecca F Rosenwasser,1 Senan Sultan,2 David Sutton,2 Rushab Choksi,1 Benjamin J Epstein3 1East Coast Institute for Research, Jacksonville, FL, USA; 2Northeast Florida Endocrine and Diabetes Associates, Jacksonville, FL, USA; 3Department of Pharmacotherapy and Translational Research, University of Florida College of Pharmacy, Gainesville, FL, USA Abstract: Diabetes remains a burgeoning global problem, necessitating ongoing efforts on the part of pharmaceutical and device manufacturers, patients, and society to curb the frightening trends in morbidity and mortality attributable to the malady. Since 1835 when phlorizin was discovered, sodium glucose co-transporter 2 (SGLT-2 inhibitors have rested tantalizingly on the horizon, promising a more physiological approach to glucose control. These agents lower glucose by enhancing its excretion by blocking reabsorption in the renal tubules, thus eliminating glucose from the body along with the molecules' attendant effects on caloric balance, plasma osmolality, and lipids. Consequently, SGLT-2 inhibitors improve glucose control to an extent comparable to other hypoglycemic agents while simultaneously reducing body weight, blood pressure, and cholesterol – an admirable portfolio. One agent, canagliflozin, has recently been approved by the US Food and Drug Administration (FDA and two other agents have progressed through Phase III trials, including dapagliflozin and empagliflozin. Collectively, when used as monotherapy, these agents have demonstrated reductions in hemoglobin A1c (HbA1c, body weight, and blood pressure of –0.34% to –1.03%, –2.0 to -3.4 kg, and –1.7 to –6.4 mmHg/–0.3 to –2.6 mmHg (systolic blood pressure/diastolic blood pressure, respectively. SGLT-2 inhibitors have been well tolerated, with hypoglycemia (0.9% to 4.3% occurring infrequently in clinical trials. Safety signals related to breast and bladder cancer have arisen with dapagliflozin, though these are unsubstantiated
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Ballester Pla, Coralio
2012-03-01
Full Text Available The observation of the actual behavior by economic decision makers in the lab and in the field justifies that bounded rationality has been a generally accepted assumption in many socio-economic models. The goal of this paper is to illustrate the difficulties involved in providing a correct definition of what a rational (or irrational agent is. In this paper we describe two frameworks that employ different approaches for analyzing bounded rationality. The first is a spatial segregation set-up that encompasses two optimization methodologies: backward induction and forward induction. The main result is that, even under the same state of knowledge, rational and non-rational agents may match their actions. The second framework elaborates on the relationship between irrationality and informational restrictions. We use the beauty contest (Nagel, 1995 as a device to explain this relationship.
La observación del comportamiento de los agentes económicos tanto en el laboratorio como en la vida real justifica que la racionalidad acotada sea un supuesto aceptado en numerosos modelos socio-económicos. El objetivo de este artículo es ilustrar las dificultades que conlleva una correcta definición de qué es un agente racional (irracional. En este artículo se describen dos marcos que emplean diferentes metodologías para analizar la racionalidad acotada. El primero es un modelo de segregación espacial donde se contrastan dos metodologías de optimización: inducción hacia atrás y hacia adelante. El resultado principal es que, incluso con el mismo nivel de conocimiento, tanto agentes racionales como irracionales podrían coincidir en sus acciones. El segundo marco trabaja sobre la relación entre irracionalidad y restricción de información. Se utiliza el juego llamado “beauty contest” (Nagel 1995 como mecanismo para explicar dicha relación.
Scheen, André J
2015-01-01
Inhibitors of sodium-glucose co-transporter type 2 (SGLT2) are proposed as a novel approach for the management of type 2 diabetes mellitus (T2DM). Several compounds are already available in many countries (dapagliflozin, canagliflozin, empagliflozin and ipragliflozin) and some others are in a late phase of development. The available SGLT2 inhibitors share similar pharmacokinetic characteristics, with a rapid oral absorption, a long elimination half-life allowing once-daily administration, an extensive hepatic metabolism mainly via glucuronidation to inactive metabolites, the absence of clinically relevant drug-drug interactions and a low renal elimination as parent drug. SGLT2 co-transporters are responsible for reabsorption of most (90 %) of the glucose filtered by the kidneys. The pharmacological inhibition of SGLT2 co-transporters reduces hyperglycaemia by decreasing renal glucose threshold and thereby increasing urinary glucose excretion. The amount of glucose excreted in the urine depends on both the level of hyperglycaemia and the glomerular filtration rate. Results of numerous placebo-controlled randomised clinical trials of 12-104 weeks duration have shown significant reductions in glycated haemoglobin (HbA1c), resulting in a significant increase in the proportion of patients reaching HbA1c targets, and a significant lowering of fasting plasma glucose when SGLT2 inhibitors were administered as monotherapy or in addition to other glucose-lowering therapies including insulin in patients with T2DM. In head-to-head trials of up to 2 years, SGLT2 inhibitors exerted similar glucose-lowering activity to metformin, sulphonylureas or sitagliptin. The durability of the glucose-lowering effect of SGLT2 inhibitors appears to be better; however, this remains to be more extensively investigated. The risk of hypoglycaemia was much lower with SGLT2 inhibitors than with sulphonylureas and was similarly low as that reported with metformin, pioglitazone or sitagliptin
Bader, Nimrah; Mirza, Lubna
2016-01-01
We are reporting a timely case of atypical euglycemic diabetic ketoacidosis in a type 1 diabetic patient treated with sodium-glucose cotransporter-2 (SGLT-2) inhibitor canagliflozin. The clinical history, physical examination findings and laboratory values are described. Other causes of acidosis such as salicylate toxicity or alcohol intoxication were excluded. Ketoacidosis resolved after increasing dextrose and insulin doses supporting the hypothesis that SGLT-2 inhibitors may lead to hypoinsulinemia. Euglycemic ketoacidosis did not recur in our patient after discontinuing canagliflozin. We recommend reserving SGLT2 inhibitor therapy to type 2 diabetics, discontinuing medication and treating patients presenting with ketoacidosis due to SGLT-2 inhibitors with higher concentrations of dextrose with appropriate doses of insulin to help resolve acidosis. PMID:27375734
Institute of Scientific and Technical Information of China (English)
郭琳; 李强
2016-01-01
Mechanism complementary, simple and effective treatment is important for decreasing the blood glucose level of type 2 diabetes patient. Aglycone SGLT2 inhibitors with competitive combined glucose transporters, effectively restrain the activity of renal proximal convoluted tubules SGLT-2, reduce renal tubular epithelial cells reabsorption of glucose, increase the excretion of urine glucose, thereby reducing the blood sugar level. Because the mechanism is not dependent on insulin secretion and insulin action of unique mechanism of action of SGLT2 inhibitor is especially suitable for as a choice for insulin combined treatment drugs. This paper reviews the basic evidence for insulin combined SGLT-2 inhibitor treatment in the following respects:starting time, patients and safety, to point out the combination therapy in the treatment of type 2 diabetes will have good application prospects.%机制互补且简单有效的治疗方案更利于2型糖尿病患者的血糖管理。S G LT-2抑制剂的糖苷配基通过与葡萄糖竞争性结合转运蛋白，有效抑制肾脏近曲小管S G LT-2的活性，减少肾小管上皮细胞对葡萄糖的重吸收，使尿葡萄糖排泄增加，从而降低血糖水平。由于其不依赖于胰岛素分泌和胰岛素作用的独特的作用机制，SGLT-2抑制剂特别适合作为胰岛素联合治疗的选择药物。本文综述了基础胰岛素联合SGLT-2抑制剂治疗的循证证据、起始时机、适应人群和安全性，指出这种联合治疗在2型糖尿病的治疗中将拥有良好的应用前景。
Role of SGLT2 inhibitors in the treatment of type 2 diabetes mellitus.
Solini, Anna
2016-12-01
In the last ten years, knowledge on pathophysiology of type 2 diabetes (T2DM) has significantly increased, with multiple failures (decreased incretin effect, increased lipolysis, increased glucagon secretion, neurotransmitters dysfunction) recognized as important contributors, together with decreased insulin secretion and reduced peripheral glucose uptake. As a consequence, the pharmacologic therapy of T2DM has been progressively enriched by several novel classes of drugs, trying to overcome these defects. The last, intriguing compounds come into the market are SGLT2 inhibitors, framing the kidney in a different scenario, not as site of a harmful disease complication, but rather as the means to correct hyperglycemia and fight the disease. This review aims to offer a short, updated overview of the role of these compounds in the treatment of T2DM, focusing on efficacy, ancillary albeit relevant clinical effects, safety, potential cardiovascular protection, positioning in common therapeutic algorithms.
Sodium-dependent reorganization of the sugar-binding site of SGLT1
DEFF Research Database (Denmark)
Hirayama, Bruce A; Loo, Donald D F; Díez-Sampedro, Ana
2007-01-01
of interactions between mutated residues and hydroxyls on the pyranose ring was assessed by comparing the affinities of deoxy sugars to those of glucose. We determined conformation-dependent accessibility to the mutated residues by both a traditional substituted cysteine accessibility method (SCAM) and a new......The sodium-dependent glucose cotransporter SGLT1 undergoes a series of voltage- and ligand-induced conformational changes that underlie the cotransport mechanism. In this study we describe how the binding of external Na changes the conformation of the sugar-binding domain, exposing residues...... that are involved in sugar recognition to the external environment. We constructed 15 individual Cys mutants in the four transmembrane helices (TMHs) that form the sugar binding and translocation domain. Each mutant was functionally characterized for transport kinetics and substrate specificity. Identification...
Bader, Nimrah; Mirza, Lubna
2016-01-01
We are reporting a timely case of atypical euglycemic diabetic ketoacidosis in a type 1 diabetic patient treated with sodium-glucose cotransporter-2 (SGLT-2) inhibitor canagliflozin. The clinical history, physical examination findings and laboratory values are described. Other causes of acidosis such as salicylate toxicity or alcohol intoxication were excluded. Ketoacidosis resolved after increasing dextrose and insulin doses supporting the hypothesis that SGLT-2 inhibitors may lead to hypoin...
Directory of Open Access Journals (Sweden)
Seufert J
2015-11-01
Full Text Available Jochen SeufertDepartment of Endocrinology and Diabetology, Clinic for Internal Medicine II, Freiburg University Hospital, Freiburg, GermanyAbstract: Despite the availability of a great variety of medications, a significant proportion of people with type 2 diabetes mellitus (T2DM are not able to achieve or maintain adequate glycemic control. Beyond improved glucose control, novel treatments would ideally provide a reduction of cardiovascular risk, with a favorable impact on excess weight, and a low intrinsic hypoglycemia risk, as well as a synergistic mechanism of action for broad combination therapy. With the development of sodium glucose cotransporter 2 (SGLT2 inhibitors, an antidiabetic pharmacologic option has recently become available that comes close to meeting these requirements. For the first time, SGLT2 inhibitors offer a therapeutic approach acting directly on the kidneys without requiring insulin secretion or action. Canagliflozin, dapagliflozin, and empagliflozin are the SGLT2 inhibitors approved to date. Taken once a day, these medications can be combined with all other antidiabetic medications including insulin, due to their insulin-independent mechanism of action, with only a minimal risk of hypoglycemia. SGLT2 inhibitors provide additional reductions in body weight and blood pressure due to the therapeutically induced excretion of glucose and sodium through the kidneys. These "concomitant effects" are particularly interesting with regard to the increased cardiovascular risk in T2DM. In many cases, T2DM treatment requires a multidimensional approach where the treatment goals have to be adapted to the individual patient. While there is a consensus on the use of metformin as a first-line drug therapy, various antidiabetics are used for treatment intensification. New mechanisms of action like that of SGLT2 inhibitors such as canagliflozin, which can be used both in early and late stages of diabetes, are a welcome addition to expand
Institute of Scientific and Technical Information of China (English)
赵晓娟; 赵永红; 刘秀菊
2015-01-01
Blood glucose levels lowered by sodium-glucose cotransporter 2 (SGLT-2) inhibitor that could reduced reabsorption of glucose by human kidney, increased urine glucose excretion, which was a new way to treat diabetes type 2. In recent years, SGLT-2 inhibitor has also been published to treat patients with diabetes type 2, and brought new hope to them.%钠-葡萄糖协同转运蛋白-2抑制剂通过减少人体肾脏对葡萄糖的重吸收，增加尿糖的排泄，达到降低血液中葡萄糖水平的目的，从而成为治疗2型糖尿病的新途径。近年来，SGLT-2抑制剂类药物也不断的问世，给2型糖尿病患者的治疗带来了新的希望。
SY 10-2 THE ROLE OF SGLT2 INHIBITORS IN THE MANAGEMENT OF T2DM.
Jung, Chang Hee
2016-09-01
Type 2 diabetes mellitus (T2DM) is a complex endocrine and metabolic disorder and is a major global public health problem with a rapidly increasing prevalence. Although a wide range of pharmacotherapy for glycemic control in T2DM is now available, management of T2DM remains complex and challenging. The kidneys contribute to glucose homeostasis primarily by the glucose reabsorption from the glomerular filtrate. The sodium-glucose co-transporter 2 (SGLT2) inhibitors, a new class of antidiabetes agents that inhibit glucose absorption from the kidney tubule independent of insulin, offer a unique opportunity to improve outcomes for patient with T2DM.In this session, I'd like to discuss several topics regarding SGLT2 inhibitors including their glucose lowering effects, recently issued adverse effects and long-term cardiovascular benefits from the perspectives of endocrinologist.
Sakuma, Shinji; Kanamitsu, Shun; Teraoka, Yumi; Masaoka, Yoshie; Kataoka, Makoto; Yamashita, Shinji; Shirasaka, Yoshiyuki; Tamai, Ikumi; Muraoka, Masahiro; Nakatsuji, Yohji; Kida, Toshiyuki; Akashi, Mitsuru
2012-04-01
A carboxyl group-terminated polyamidoamine dendrimer (generation: 3.0) bearing arbutin, which is a substrate of Na⁺/glucose cotransporter 1 (SGLT1), via a nonbiodegradable ω-amino triethylene glycol linker (PAMAM-ARB), inhibits SGLT1-mediated D-glucose uptake, as does phloridzin, which is a typical SGLT1 inhibitor. Here, since our previous research revealed that the activity of arbutin was dramatically improved through conjugation with the dendrimer, we examined the involvement of functional groups on the dendrimer surface in inhibition of SGLT1-mediated D-glucose uptake. PAMAM-ARB, with a 6.25% arbutin content, inhibited in vitro D-glucose uptake most strongly; the inhibitory effect decreased as the arbutin content increased. In vitro experiments using arbutin-free original dendrimers indicated that dendrimer-derived carboxyl groups actively participated in SGLT1 inhibition. However, the inhibitory effect was much less than that of PAMAM-ARB and was equal to that of glucose moiety-free PAMAM-ARB. Data supported that the glucose moiety of arbutin was essential for the high activity of PAMAM-ARB in SGLT1 inhibition. Analysis of the balance of each domain further suggested that carboxyl groups anchored PAMAM-ARB to SGLT1, and the subsequent binding of arbutin-derived glucose moieties to the target sites on SGLT1 resulted in strong inhibition of SGLT1-mediated D-glucose uptake.
Hoi, Julia Katharina; Holik, Ann-Katrin; Geissler, Katrin; Hans, Joachim; Friedl, Barbara; Liszt, Kathrin; Krammer, Gerhard E.; Ley, Jakob P.; Somoza, Veronika
2017-01-01
Flavanoids and related polyphenols, among them hesperitin, have been shown to modulate cellular glucose transport by targeting SGLT-1 and GLUT-2 transport proteins. We aimed to investigate whether homoeriodictyol, which is structurally related to hesperitin, affects glucose uptake in differentiated Caco-2 cells as a model for the intestinal barrier. The results revealed that, in contrast to other polyphenols, the flavanon homoeriodictyol promotes glucose uptake by 29.0 ± 3.83% at a concentration of 100 μM. The glucose uptake stimulating effect was sensitive to phloridzin, but not to phloretin, indicating an involvement of the sodium-coupled glucose transporter SGLT-1, but not of sodium-independent glucose transporters (GLUT). In addition, in contrast to the increased extracellular serotonin levels by stimulation with 500 mM D-(+)-glucose, treatment with 100 μM homoeriodictyol decreased serotonin release by –48.8 ± 7.57% in Caco-2 cells via a phloridzin-sensitive signaling pathway. Extracellular serotonin levels were also reduced by –57.1 ± 5.43% after application of 0.01 μM homoeriodictyol to human neural SH-SY5Y cells. In conclusion, we demonstrate that homoeriodictyol affects both the glucose metabolism and the serotonin system in Caco-2 cells via a SGLT-1-meditated pathway. Furthermore, the results presented here support the usage of Caco-2 cells as a model for peripheral serotonin release. Further investigations may address the value of homoeriodictyol in the treatment of anorexia and malnutrition through the targeting of SGLT-1. PMID:28192456
Market Access through Bound Tariffs
DEFF Research Database (Denmark)
Sala, Davide; Schröder, Philipp J.H.; Yalcin, Erdal
on the risk that exporters face in destination markets. The present paper formalizes the underlying interaction of risk, fixed export costs and firms' market entry decisions based on techniques known from the real options literature; doing so we highlight the important role of bound tariffs at the extensive......WTO negotiations deal predominantly with bound - besides applied - tariff rates. But, how can reductions in tariffs ceilings, i.e. tariff rates that no exporter may ever actually be confronted with, generate market access? The answer to this question relates to the effects of tariff bindings...... margin of trade. We find that bound tariffs are more effective with higher risk destination markets, that a large binding overhang may still command substantial market access, and that reductions in bound tariffs generate effective market access even when bound rates are above current and long...
Market access through bound tariffs
DEFF Research Database (Denmark)
Sala, Davide; Schröder, Philipp J.H.; Yalcin, Erdal
2010-01-01
on the risk that exporters face in destination markets. The present paper formalizes the underlying interaction of risk, fixed export costs and firms' market entry decisions based on techniques known from the real options literature; doing so we highlight the important role of bound tariffs at the extensive......WTO negotiations deal predominantly with bound - besides applied - tariff rates. But, how can reductions in tariffs ceilings, i.e. tariff rates that no exporter may ever actually be confronted with, generate market access? The answer to this question relates to the effects of tariff bindings...... margin of trade. We find that bound tariffs are more effective with higher risk destination markets, that a large binding overhang may still command substantial market access, and that reductions in bound tariffs generate effective market access even when bound rates are above current and longterm...
O'Neill, Julie; Fasching, Angelica; Pihl, Liselotte; Patinha, Daniela; Franzén, Stephanie; Palm, Fredrik
2015-08-01
Early stage diabetic nephropathy is characterized by glomerular hyperfiltration and reduced renal tissue Po2. Recent observations have indicated that increased tubular Na(+)-glucose linked transport (SGLT) plays a role in the development of diabetes-induced hyperfiltration. The aim of the present study was to determine how inhibition of SLGT impacts upon Po2 in the diabetic rat kidney. Diabetes was induced by streptozotocin in Sprague-Dawley rats 2 wk before experimentation. Renal hemodynamics, excretory function, and renal O2 homeostasis were measured in anesthetized control and diabetic rats during baseline and after acute SGLT inhibition using phlorizin (200 mg/kg ip). Baseline arterial pressure was similar in both groups and unaffected by SGLT inhibition. Diabetic animals displayed reduced baseline Po2 in both the cortex and medulla. SGLT inhibition improved cortical Po2 in the diabetic kidney, whereas it reduced medullary Po2 in both groups. SGLT inhibition reduced Na(+) transport efficiency [tubular Na(+) transport (TNa)/renal O2 consumption (Qo2)] in the control kidney, whereas the already reduced TNa/Qo2 in the diabetic kidney was unaffected by SGLT inhibition. In conclusion, these data demonstrate that when SGLT is inhibited, renal cortex Po2 in the diabetic rat kidney is normalized, which implies that increased proximal tubule transport contributes to the development of hypoxia in the diabetic kidney. The reduction in medullary Po2 in both control and diabetic kidneys during the inhibition of proximal Na(+) reabsorption suggests the redistribution of active Na(+) transport to less efficient nephron segments, such as the medullary thick ascending limb, which results in medullary hypoxia.
Directory of Open Access Journals (Sweden)
Xin Jin
Full Text Available Delphinidin-3-glucoside (Dp is a member of a family of bioactive compounds known as anthocyanins that occur naturally in pigmented plants and are known to ameliorate oxidative stress. Previous studies have showed that Dp decreased oxidative stress in vascular endothelial cells, however, the underlying mechanisms remain largely unknown. In the present study, we showed that pretreatment with Dp significantly suppressed oxidized low-density lipoprotein (oxLDL-induced cell proliferation inhibition and apoptosis in primary human umbilical vein endothelial cells (HUVECs. Also, Dp pretreatment attenuated oxLDL-induced mitochondrial dysfunction via decreased reactive oxygen species (ROS and superoxide anion generation, thereby repressing mitochondrial membrane potential and closing mitochondrial permeability transition pore. Furthermore, in vitro and in vivo data showed that Dp was transported into endothelial cells in a temperature, concentration, and time-dependent manner via the sodium-dependent glucose transporter (SGLT1. Suppression of SGLT1 by its substrate glucose, its inhibitor phlorizin or SGLT1 siRNA blocked Dp transportation. Repression of SGLT1 significantly inhibited Dp function of ameliorating mitochondrial dysfunction induced by pro-apoptotic factors (Apoptosis-inducing factor, Cytochrome c, Caspase-3 and Bax/Bcl-2 ratio. Taken together, our data indicate that Dp protects VECs via the SGLT1-ROS-mitochodria pathway. This new insight may help to elucidate the molecular mechanisms underlying the vascular protection afforded by Dp, and anthocyanins in general, in the context of prevention of endothelial dysfunction and atherosclerosis.
Mamidi, Rao N V S; Proctor, Jim; De Jonghe, Sandra; Feyen, Bianca; Moesen, Esther; Vinken, Petra; Ma, Jing Ying; Bryant, Stewart; Snook, Sandra; Louden, Calvert; Lammens, Godelieve; Ways, Kirk; Kelley, Michael F; Johnson, Mark D
2014-09-25
Canagliflozin is an SGLT2 inhibitor used for the treatment of type 2 diabetes mellitus. Studies were conducted to investigate the mechanism responsible for renal tubular tumors and pheochromocytomas observed at the high dose in a 2-year carcinogenicity study in rats. At the high dose (100mg/kg) in rats, canagliflozin caused carbohydrate malabsorption evidenced by inhibition of intestinal glucose uptake, decreased intestinal pH and increased urinary calcium excretion. In a 6-month mechanistic study utilization of a glucose-free diet prevented carbohydrate malabsorption and its sequelae, including increased calcium absorption and urinary calcium excretion, and hyperostosis. Cell proliferation in the kidney and adrenal medulla was increased in rats maintained on standard diet and administered canagliflozin (100mg/kg), and in addition an increase in the renal injury biomarker KIM-1 was observed. Increased cell proliferation is considered as a proximal event in carcinogenesis. Effects on cell proliferation, KIM-1 and calcium excretion were inhibited in rats maintained on the glucose-free diet, indicating they are secondary to carbohydrate malabsorption and are not direct effects of canagliflozin. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.
[Canagliflozin (Invokana): kidney SGLT2 cotransporter inhibitor for treating type 2 diabetes].
Scheen, A J
2014-12-01
Canagliflozin is an inhibitor of sodium-glucose cotransporters type 2 (SGLT2) that are present in renal tubules. This specific insulin-independent mechanism promotes glucosuria, which results in a reduction in fasting and postprandial glycaemia and a decrease of glycated haemoglobin (HbA(1c)). Furthermore, canagliflozin promotes weight loss and lowers arterial (mainly systolic) blood pressure. Its efficacy is decreased in patients with renal insufficiency and the treatment should be stopped if estimated glomerular filtration rate is below 45 ml/min/1.73 m2. Both the efficacy and safety of canagliflozin have been investigated in 24 to 104-week controlled trials versus placebo or versus an active comparator (glimepiride or sitagliptin). The mean reduction in HbA(1c) averages 0.75% when added to other treatments, as compared to placebo. The 100 mg dose is as active as sitagliptin 100 mg while the 300 mg canagliflozin dose is even more efficacious. Adverse events are mostly mycotic genital infections and more rarely mild urinary tract infections. Caution is required in elderly patients and the risk of volume depletion should be checked (hypotension). Hypoglycaemia may occur only in patients already treated with an insulin-secreting agent or insulin. Canagliflozin is commercialized under the trade name Invokana, at the doses of 100 mg and 300 mg once daily, for the treatment of type 2 diabetes.
Putapatri, Siddamal Reddy; Kanwal, Abhinav; Banerjee, Sanjay K; Kantevari, Srinivas
2014-03-15
Sodium-glucose co-transporter (SGLT) inhibitors are a novel class of therapeutic agents for the treatment of type 2 diabetes by preventing renal glucose reabsorption. In our efforts to identify novel inhibitors of SGLT, we synthesized a series of l-rhamnose derived acyclic C-nucleosides with 1,2,3-triazole core. The key β-ketoester building block 4 prepared from l-rhamnose in five steps, was reacted with various aryl azides to produce the respective 1,2,3-triazole derivatives in excellent yields. Deprotection of acetonide group gave the desired acyclic C-nucleosides 7a-o. All the new compounds were screened for their sodium-glucose co-transporters (SGLT1 and SGLT2) inhibition activity using recently developed cell-based nonradioactive fluorescence glucose uptake assay. Among them, 7m with IC50: 125.9nM emerged as the most potent SGLT2 inhibitor. On the other hand compound 7d exhibited best selectivity for inhibition of SGLT2 (IC50: 149.1nM) over SGLT1 (IC50: 693.2nM). The results presented here demonstrated the utility of acyclic C-nucleosides as novel SGLT inhibitors for future investigations.
Scheen, André J
2014-04-01
Inhibitors of sodium-glucose cotransporters type 2 (SGLT2) reduce hyperglycaemia by decreasing renal glucose threshold and thereby increasing urinary glucose excretion. They are proposed as a novel approach for the management of type 2 diabetes mellitus. They have proven their efficacy in reducing glycated haemoglobin, without inducing hypoglycaemia, as monotherapy or in combination with various other glucose-lowering agents, with the add-on value of promoting some weight loss and lowering arterial blood pressure. As they may be used concomitantly with many other drugs, we review the potential drug-drug interactions (DDIs) regarding the three leaders in the class (dapagliglozin, canagliflozin and empagliflozin). Most of the available studies were performed in healthy volunteers and have assessed the pharmacokinetic interferences with a single administration of the SGLT2 inhibitor. The exposure [assessed by peak plasma concentrations (Cmax) and area under the concentration-time curve (AUC)] to each SGLT2 inhibitor tested was not significantly influenced by the concomitant administration of other glucose-lowering agents or cardiovascular agents commonly used in patients with type 2 diabetes. Reciprocally, these medications did not influence the pharmacokinetic parameters of dapagliflozin, canagliflozin or empagliflozin. Some modest changes were not considered as clinically relevant. However, drugs that could specifically interfere with the metabolic pathways of SGLT2 inhibitors [rifampicin, inhibitors or inducers of uridine diphosphate-glucuronosyltransferase (UGT)] may result in significant changes in the exposure of SGLT2 inhibitors, as shown for dapagliflozin and canagliflozin. Potential DDIs in patients with type 2 diabetes receiving chronic treatment with an SGLT2 inhibitor deserve further attention, especially in individuals treated with several medications or in more fragile patients with hepatic and/or renal impairment.
Directory of Open Access Journals (Sweden)
Joshua J Neumiller
2014-06-01
Full Text Available Type 2 diabetes is increasing in prevalence worldwide, and hyperglycemia is often poorly controlled despite a number of therapeutic options. Unlike previously available agents, sodium-glucose co-transporter 2 (SGLT2 inhibitors offer an insulin-independent mechanism for improving blood glucose levels, since they promote urinary glucose excretion (UGE by inhibiting glucose reabsorption in the kidney. In addition to glucose control, SGLT2 inhibitors are associated with weight loss and blood pressure reductions, and do not increase the risk of hypoglycemia. Empagliflozin is a selective inhibitor of SGLT2, providing dose-dependent UGE increases in healthy volunteers, with up to 90 g of glucose excreted per day. It can be administered orally, and studies of people with renal or hepatic impairment indicated empagliflozin needed no dose adjustment based on pharmacokinetics. In Phase II trials in patients with type 2 diabetes, empagliflozin provided improvements in glycosylated hemoglobin (HbA1c and other measures of glycemic control when given as monotherapy or add-on to metformin, as well as reductions in weight and systolic blood pressure. As add-on to basal insulin, empagliflozin not only improved HbA1c levels but also reduced insulin doses. Across studies, empagliflozin was generally well tolerated with a similar rate of hypoglycemia to placebo; however, patients had a slightly increased frequency of genital infections, but not urinary tract infections, versus placebo. Phase III studies have also reported a good safety profile along with significant improvements in HbA1c, weight and blood pressure, with no increased risk of hypoglycemia versus placebo. Based on available data, it appears that empagliflozin may be a useful option in a range of patients; however, clinical decisions will be better informed by the results of ongoing studies, in particular, a large cardiovascular outcome study (EMPA-REG OUTCOME™.
Chino, Yukihiro; Samukawa, Yoshishige; Sakai, Soichi; Nakai, Yasuhiro; Yamaguchi, Jun-ichi; Nakanishi, Takeo; Tamai, Ikumi
2014-01-01
Sodium glucose cotransporter 2 (SGLT2) inhibitors have been reported to lower the serum uric acid (SUA) level. To elucidate the mechanism responsible for this reduction, SUA and the urinary excretion rate of uric acid (UEUA) were analysed after the oral administration of luseogliflozin, a SGLT2 inhibitor, to healthy subjects. After dosing, SUA decreased, and a negative correlation was observed between the SUA level and the UEUA, suggesting that SUA decreased as a result of the increase in the UEUA. The increase in UEUA was correlated with an increase in urinary d-glucose excretion, but not with the plasma luseogliflozin concentration. Additionally, in vitro transport experiments showed that luseogliflozin had no direct effect on the transporters involved in renal UA reabsorption. To explain that the increase in UEUA is likely due to glycosuria, the study focused on the facilitative glucose transporter 9 isoform 2 (GLUT9ΔN, SLC2A9b), which is expressed at the apical membrane of the kidney tubular cells and transports both UA and d-glucose. It was observed that the efflux of [14C]UA in Xenopus oocytes expressing the GLUT9 isoform 2 was trans-stimulated by 10 mm d-glucose, a high concentration of glucose that existed under SGLT2 inhibition. On the other hand, the uptake of [14C]UA by oocytes was cis-inhibited by 100 mm d-glucose, a concentration assumed to exist in collecting ducts. In conclusion, it was demonstrated that the UEUA could potentially be increased by luseogliflozin-induced glycosuria, with alterations of UA transport activity because of urinary glucose. PMID:25044127
Hatanaka, Takashi; Ogawa, Daisuke; Tachibana, Hiromi; Eguchi, Jun; Inoue, Tatsuyuki; Yamada, Hiroshi; Takei, Kohji; Makino, Hirofumi; Wada, Jun
2016-08-01
It is unclear whether the improvement in diabetic nephropathy by sodium glucose cotransporter 2 (SGLT2) inhibitors is caused by a direct effect on SGLT2 or by the improvement in hyperglycemia. Here, we investigated the effect of dapagliflozin on early-stage diabetic nephropathy using a mouse model of type 1 diabetes and murine proximal tubular epithelial cells. Eight-week-old Akita mice were treated with dapagliflozin or insulin for 12 weeks. Body weight, urinary albumin excretion, blood pressure, as well as levels of blood glucose and hemoglobin A1c were measured. Expansion of the mesangial matrix, interstitial fibrosis, and macrophage infiltration in kidneys were evaluated by histology. Oxidative stress and apoptosis were evaluated in kidneys and cultured proximal tubular epithelial cells. Compared with nontreated mice, dapagliflozin and insulin decreased blood glucose and hemoglobin A1c levels equally. Urine volume and water intake increased significantly in the dapagliflozin-treated group compared with those in the insulin-treated group, but there were no differences in body weight or blood pressure between the two groups. Macrophage infiltration and fibrosis in renal interstitium improved significantly in the dapagliflozin group compared with the insulin group. Oxidative stress was attenuated by dapagliflozin, and suppression occurred in a dose-dependent manner. RNAi knockdown of SGLT2 resulted in reduced oxidative stress. Dapagliflozin ameliorates diabetic nephropathy by suppressing hyperglycemia-induced oxidative stress in a manner independent of hyperglycemia improvement in Akita mice. Our findings suggest that dapagliflozin may be a novel therapeutic approach for the treatment of diabetic nephropathy.
[EMPAGLIFLOZIN (JARDIANCE) :Nw SGLT2 COTRANSPORTER INHIBITOR FOR TREATING TYPE 2 DIABETES].
Scheen, A J
2015-09-01
Empagliflozin is a new inhibitor of sodiumglucose cotransporters type 2 (SGLT2) for the treatment of type 2 diabetes mellitus (T2DM). Its specific action inhibits glucose reabsorption in renal tubules and thus promotes glucosuria. This effect results in a reduction in fasting and postprandial glycaemia and a decrease of glycated haemoglobin (HbA(Ic)), independently of insulin. Furthermore, calorie urinary loss promotes weight reduction and osmotic diuresis lowers arterial blood pressure. The efficacy of empagliflozin increases according to the level of hyperglycaemia but decreases in patients with renal insufficiency. In 24 to 104-week controlled trials versus placebo, empagliflozin reduces HbA(1c) (approximately 0.8%), without hypoglycaemia (except in patients already treated with insulin or sulphonylureas). This improvement in glucose control is rather similar to that observed with active comparators (metformin, glimepiride or sitagliptin), with the advantage for empagliflozin of reducing body weight (approximately 2 kg) and blood pressure (systolic approximately 4 mm Hg and diastolic approximately 2 mm Hg). Empagliflozin has shown a cardiovascular protection in the EMPA-REG OUTCOME trial. Mycotic genital infections occur more frequently, especially in women, while a negligible increase in mild urinary tract infections may be observed. The risk of hypotension and volume depletion is low, although it should be carefully checked in more fragile and at risk patients. Empagliflozin (Jardiance), which is commercialized at the doses of 10 mg and 25 mg once daily, is indicated for the treatment of T2DM and reimbursed in Belgium with conditions as add-on to a background glucose-lowering therapy.
Institute of Scientific and Technical Information of China (English)
牟博佼; 李岩; 朱岩
2012-01-01
Bounded rationality has become an important research focus in operations management.This paper summarizes the current results in this field related to the behavioral theories underlying the research and conclusions from behavioral experiments and analytical modeling.Finally,this paper gives some directions for future research,including studies on selling multiple products and vertical/horizontal competition in multiple periods using bounded rationality.%有限理性成为近年来运营管理领域关注的热点,本文归纳分析了该类问题的阶段性研究成果。本文首先提炼出该类研究采用的行为理论基础,然后从行为实验和建模分析2种方法视角介绍了研究焦点以及取得的结论。最后基于研究现状展望了该领域的未来发展,指出未来研究可以针对单周期多产品、多周期纵向/横向竞争等系统展开分析。
Viscosity bound versus the universal relaxation bound
Hod, Shahar
2017-10-01
For gauge theories with an Einstein gravity dual, the AdS/CFT correspondence predicts a universal value for the ratio of the shear viscosity to the entropy density, η / s = 1 / 4 π. The holographic calculations have motivated the formulation of the celebrated KSS conjecture, according to which all fluids conform to the lower bound η / s ≥ 1 / 4 π. The bound on η / s may be regarded as a lower bound on the relaxation properties of perturbed fluids and it has been the focus of much recent attention. In particular, it was argued that for a class of field theories with Gauss-Bonnet gravity dual, the shear viscosity to entropy density ratio, η / s, could violate the conjectured KSS bound. In the present paper we argue that the proposed violations of the KSS bound are strongly constrained by Bekenstein's generalized second law (GSL) of thermodynamics. In particular, it is shown that physical consistency of the Gauss-Bonnet theory with the GSL requires its coupling constant to be bounded by λGB ≲ 0 . 063. We further argue that the genuine physical bound on the relaxation properties of physically consistent fluids is ℑω(k > 2 πT) > πT, where ω and k are respectively the proper frequency and the wavenumber of a perturbation mode in the fluid.
Institute of Scientific and Technical Information of China (English)
顾问
2015-01-01
通过对江苏省高职院校拓展训练校内培训开展的现状调查研究,构建符合高职教育规律的拓展训练培训实践操作模式,提升拓展训练校内培训的针对性、实效性,从而更系统高效地助推高职学生综合素质提升.%Through the investigation and research on the current situation of the development of outward bound of higher vocational colleges in Jiangsu province, the practical operation mode of the higher vocational education was constructed, which can improve the pertinence and effectiveness of the school training so as to more efficient improve the comprehensive quality of higher vocational college students.
Functions of bounded variation
Lind, Martin
2006-01-01
The paper begins with a short survey of monotone functions. The functions of bounded variation are introduced and some basic properties of these functions are given. Finally the jump function of a function of bounded variation is defined.
Felker, Susan B.
2005-01-01
Robert Cobb Jr., of Greensboro, N.C., a 1986-89 participant in the Virginia Tech Upward Bound program, was recently named Virginia's TRIO Achiever for 2004. Federal TRIO programs include Upward Bound and Educational Talent Search.
Directory of Open Access Journals (Sweden)
Ina Bisha
2014-12-01
Full Text Available Sodium-Galactose Transporter (SGLT is a secondary active symporter which accumulates sugars into cells by using the electrochemical gradient of Na+ across the membrane. Previous computational studies provided insights into the release process of the two ligands (galactose and sodium ion into the cytoplasm from the inward-facing conformation of Vibrio parahaemolyticus sodium/galactose transporter (vSGLT. Several aspects of the transport mechanism of this symporter remain to be clarified: (i a detailed kinetic and thermodynamic characterization of the exit path of the two ligands is still lacking; (ii contradictory conclusions have been drawn concerning the gating role of Y263; (iii the role of Na+ in modulating the release path of galactose is not clear. In this work, we use bias-exchange metadynamics simulations to characterize the free energy profile of the galactose and Na+ release processes toward the intracellular side. Surprisingly, we find that the exit of Na+ and galactose is non-concerted as the cooperativity between the two ligands is associated to a transition that is not rate limiting. The dissociation barriers are of the order of 11-12 kcal/mol for both the ion and the substrate, in line with kinetic information concerning this type of transporters. On the basis of these results we propose a branched six-state alternating access mechanism, which may be shared also by other members of the LeuT-fold transporters.
Directory of Open Access Journals (Sweden)
Deepu Daniel
2015-04-01
Full Text Available Diabetes is one of the most common diseases encountered in both the outpatient and inpatient settings. According to data from the 2011 National Diabetes Fact Sheet, approximately 8.3% (25.8 million of the entire American population have diabetes. Of this population, about 72.9% (18.8 million have been clinically diagnosed while an estimated 27.1% (7.0 million remain undiagnosed. According to the study Economic Costs of Diabetes in the U.S. in 2012, the total national cost of diagnosed diabetes, including direct medical cost and reduced productivity was nearly $245 billion. Extensive research efforts have gone into developing new pharmacologic agents to treat diabetes. The newest medications recently approved by the FDA are the SGLT2 inhibitors. This article will explain the mechanism of the action of this class of drugs along with their specific role in diabetic management. This article will focus on canagliflozin and dapagliflozin, the two most well researched and studied drugs of SGLT2 inhibitors, both of which have been approved for use by the Food and Drug Administration. Some of the major trials concerning both of these drugs will be presented in this article.
Jabbour, Serge A; Whaley, Jean M; Tirmenstein, Mark; Poucher, Simon M; Reilly, Timothy P; Boulton, David W; Saye, Joanne; List, James F; Parikh, Shamik
2012-07-01
Sodium-glucose co-transporter 2 (SGLT2) plays a key role in glucose homeostasis as the key transporter responsible for most renal glucose reabsorption in the proximal tubules of the kidney. Dapagliflozin is a potent, selective, and reversible inhibitor of SGLT2 that lowers blood glucose levels in an insulin-independent fashion. This novel agent has been studied extensively in patients with type 2 diabetes mellitus (T2DM). In these clinical trials, dapagliflozin significantly decreased glycated hemoglobin and fasting plasma glucose levels when administered alone or as add-on treatment in patients who were already receiving metformin, a sulfonylurea (glimepiride), pioglitazone, or insulin. Moreover, dapagliflozin decreased body weight when taken as monotherapy or in combination with metformin, a sulfonylurea, or insulin, and mitigated weight gain in patients receiving pioglitazone. Consistent with preclinical toxicology studies, dapagliflozin has a manageable adverse event profile that is largely predictable from its mechanism of action. While there are no clinically significant negative effects on renal function or electrolytes, dapagliflozin treatment is associated with increased frequencies of urinary tract infections and vulvovaginitis/balanitis. With a mechanism of action that is distinct from and complementary to that of existing antihyperglycemic therapies, dapagliflozin is an effective antihyperglycemic agent that is well tolerated and may enhance weight loss. As such, dapagliflozin promises to become an important adjunctive therapy for comprehensive treatment of T2DM.
Sabino-Silva, Robinson; Alves-Wagner, Ana B T; Burgi, Katia; Okamoto, Maristela M; Alves, Adilson S; Lima, Guilherme A; Freitas, Helayne S; Antunes, Vagner R; Machado, Ubiratan F
2010-12-01
Salivary gland dysfunction is a feature in diabetes and hypertension. We hypothesized that sodium-glucose cotransporter 1 (SGLT1) participates in salivary dysfunctions through a sympathetic- and protein kinase A (PKA)-mediated pathway. In Wistar-Kyoto (WKY), diabetic WKY (WKY-D), spontaneously hypertensive (SHR), and diabetic SHR (SHR-D) rats, PKA/SGLT1 proteins were analyzed in parotid and submandibular glands, and the sympathetic nerve activity (SNA) to the glands was monitored. Basal SNA was threefold higher in SHR (P acinar cells were regulated in parallel to the SNA. Electrical stimulation of the sympathetic branch to salivary glands increased (∼30%, P acinar cells. Taken together, our results show highly coordinated regulation of sympathetic activity upon PKA activity and plasma membrane SGLT1 content in salivary glands. Furthermore, the present findings show that diabetic- and/or hypertensive-induced changes in the sympathetic activity correlate with changes in SGLT1 expression in basolateral membrane of acinar cells, which can participate in the salivary glands dysfunctions reported by patients with these pathologies.
Kuhre, Rune Ehrenreich; Bechmann, Louise Ellegaard; Wewer Albrechtsen, Nicolai Jacob; Hartmann, Bolette; Holst, Jens Juul
2015-06-15
Neurotensin (NT) is a neurohormone produced in the central nervous system and in the gut epithelium by the enteroendocrine N cell. NT may play a role in appetite regulation and may have potential in obesity treatment. Glucose ingestion stimulates NT secretion in healthy young humans, but the mechanisms involved are not well understood. Here, we show that rats express NT in the gut and that glucose gavage stimulates secretion similarly to oral glucose in humans. Therefore, we conducted experiments on isolated perfused rat small intestine with a view to characterize the cellular pathways of secretion. Luminal glucose (20% wt/vol) stimulated secretion but vascular glucose (5, 10, or 15 mmol/l) was without effect. The underlying mechanisms depend on membrane depolarization and calcium influx, since the voltage-gated calcium channel inhibitor nifedipine and the KATP channel opener diazoxide, which causes hyperpolarization, eliminated the response. Luminal inhibition of the sodium-glucose cotransporter 1 (SGLT1) (by phloridzin) eliminated glucose-stimulated release as well as secretion stimulated by luminal methyl-α-D-glucopyranoside (20% wt/vol), a metabolically inactive SGLT1 substrate, suggesting that glucose stimulates secretion by initial uptake by this transporter. However, secretion was also sensitive to GLUT2 inhibition (by phloretin) and blockage of oxidative phosphorylation (2-4-dinitrophenol). Direct KATP channel closure by sulfonylureas stimulated secretion. Therefore, glucose stimulates NT secretion by uptake through SGLT1 and GLUT2, both causing depolarization either as a consequence of sodium-coupled uptake (SGLT1) or by closure of KATP channels (GLUT2 and SGLT1) secondary to the ATP-generating metabolism of glucose.
Moran, Andrew W; Al-Rammahi, Miran A; Arora, Daleep K; Batchelor, Daniel J; Coulter, Erin A; Daly, Kristian; Ionescu, Catherine; Bravo, David; Shirazi-Beechey, Soraya P
2010-09-01
In an intensive livestock production, a shorter suckling period allows more piglets to be born. However, this practice leads to a number of disorders including nutrient malabsorption, resulting in diarrhoea, malnutrition and dehydration. A number of strategies have been proposed to overcome weaning problems. Artificial sweeteners, routinely included in piglets' diet, were thought to enhance feed palatability. However, it is shown in rodent models that when included in the diet, they enhance the expression of Na+/glucose co-transporter (SGLT1) and the capacity of the gut to absorb glucose. Here, we show that supplementation of piglets' feed with a combination of artificial sweeteners saccharin and neohesperidin dihydrochalcone enhances the expression of SGLT1 and intestinal glucose transport function. Artificial sweeteners are known to act on the intestinal sweet taste receptor T1R2/T1R3 and its partner G-protein, gustducin, to activate pathways leading to SGLT1 up-regulation. Here, we demonstrate that T1R2, T1R3 and gustducin are expressed together in the enteroendocrine cells of piglet intestine. Furthermore, gut hormones secreted by the endocrine cells in response to dietary carbohydrates, glucagon-like peptides (GLP)-1, GLP-2 and glucose-dependent insulinotrophic peptide (GIP), are co-expressed with type 1 G-protein-coupled receptors (T1R) and gustducin, indicating that L- and K-enteroendocrine cells express these taste elements. In a fewer endocrine cells, T1R are also co-expressed with serotonin. Lactisole, an inhibitor of human T1R3, had no inhibitory effect on sweetener-induced SGLT1 up-regulation in piglet intestine. A better understanding of the mechanism(s) involved in sweetener up-regulation of SGLT1 will allow the identification of nutritional targets with implications for the prevention of weaning-related malabsorption.
Chen, Jiao; Fan, Fang; Wang, J. Y.; Long, Yang; Gao, C. L.; Stanton, R. C.; Xu, Yong
2017-01-01
To assess the efficacy and safety of the SGLT-2 inhibitors as adjunct therapy to insulin in T1DM, clinical trials indexed in PubMed, Cochrane Library, EMbase from inception through April 5, 2016. A meta-analysis was conducted on trials of SGLT-2 inhibitors in patients with T1DM on insulin therapy using RevMan 5.3 software. Of the 371 articles identified, ten met eligibility criteria. Seven clinical trials including four randomized controlled trials and 581 patients were included. Compared with the control group, SGLT-2 inhibitors group had significantly reduced fasting plasma glucose by 0.69 mmol/L [1.32; 0.07], glycosylated hemoglobin A1C by 0.37% [0.54; 0.20], body weight by 2.54 kg [3.48; 1.60] and total daily insulin dose by 6.22 IU [8.04; 4.40]. The total incidence of adverse events (AEs), hypoglycemia, and genital and urinary infections were also similar to placebo, while an increased incidence of diabetic ketoacidosis (DKA) (n = 16) was seen in SGLT-2 inhibitors group. The present study demonstrates that SGLT-2 inhibitors are effective as adjunct therapy to insulin in T1DM, heralding improved glycemic control, reduced body weight and total daily insulin dose without an increase in total AEs, hypoglycemia, or genital and urinary infections. However, the risk of DKA should be carefully monitored in future clinical trials. PMID:28276512
Physical Uncertainty Bounds (PUB)
Energy Technology Data Exchange (ETDEWEB)
Vaughan, Diane Elizabeth [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Preston, Dean L. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
2015-03-19
This paper introduces and motivates the need for a new methodology for determining upper bounds on the uncertainties in simulations of engineered systems due to limited fidelity in the composite continuum-level physics models needed to simulate the systems. We show that traditional uncertainty quantification methods provide, at best, a lower bound on this uncertainty. We propose to obtain bounds on the simulation uncertainties by first determining bounds on the physical quantities or processes relevant to system performance. By bounding these physics processes, as opposed to carrying out statistical analyses of the parameter sets of specific physics models or simply switching out the available physics models, one can obtain upper bounds on the uncertainties in simulated quantities of interest.
Abbasi, Nazanin N; Purslow, Peter P; Tosh, Susan M; Bakovic, Marica
2016-06-01
Oat β-glucan consumption is linked to reduced risk factors associated with diabetes and obesity by lowering glycemic response and serum level of low-density lipoproteins. The purpose of this study was to identify the mechanism of action of oat β-glucan at the interface between the gut wall and the lumen responsible for attenuating glucose levels. We proposed that viscous oat β-glucan acts as a physical barrier to glucose uptake in normally absorptive gut epithelial cells IEC-6 by affecting the expression of intestinal glucose transporters. Concentration and time-dependent changes in glucose uptake were established by using a nonmetabolizable glucose analog 2-[N-(7-nitrobenz-2-oxa-1,3-diazol-4-yl)amino]-2-deoxy-d-glucose. The effectiveness of nutrient transport in IEC-6 cells was shown by significant differences in glucose uptake and corresponding transporter expression. The expressions of glucose transporters sodium-glucose-linked transport protein 1 (SGLT1) and glucose transporter 2 (GLUT2) increased with time (0-60 minutes) and glucose levels (5-25 mmol/L). The suppression of glucose uptake and SGLT1 and GLUT2 expression by increasing concentrations (4-8 mg/mL) of oat β-glucan demonstrated a direct effect of the physical properties of oat β-glucan on glucose transport. These results affirmed oat β-glucan as a dietary agent for minimizing postprandial glucose and showed that modulating the activity of the key intestinal glucose transporters with oat β-glucan could be an effective way of lowering blood glucose levels in patients with diabetes. Copyright © 2016 Elsevier Inc. All rights reserved.
de Rham, Claudia; Tolley, Andrew J; Zhou, Shuang-Yong
2016-01-01
Recently, aLIGO has announced the first direct detections of gravitational waves, a direct manifestation of the propagating degrees of freedom of gravity. The detected signals GW150914 and GW151226 have been used to examine the basic properties of these gravitational degrees of freedom, particularly setting an upper bound on their mass. It is timely to review what the mass of these gravitational degrees of freedom means from the theoretical point of view, particularly taking into account the recent developments in constructing consistent massive gravity theories. Apart from the GW150914 mass bound, a few other observational bounds have been established from the effects of the Yukawa potential, modified dispersion relation and fifth force that are all induced when the fundamental gravitational degrees of freedom are massive. We review these different mass bounds and examine how they stand in the wake of recent theoretical developments and how they compare to the bound from GW150914.
Multicolor Bound Soliton Molecule
Luo, Rui; Lin, Qiang
2015-01-01
We show a new class of bound soliton molecule that exists in a parametrically driven nonlinear optical cavity with appropriate dispersion characteristics. The composed solitons exhibit distinctive colors but coincide in time and share a common phase, bound together via strong inter-soliton four-wave mixing and Cherenkov radiation. The multicolor bound soliton molecule shows intriguing spectral locking characteristics and remarkable capability of spectrum management to tailor soliton frequencies, which may open up a great avenue towards versatile generation and manipulation of multi-octave spanning phase-locked Kerr frequency combs, with great potential for applications in frequency metrology, optical frequency synthesis, and spectroscopy.
Institute of Scientific and Technical Information of China (English)
Wen Jing Zhao; Yong Heng Shi; Gui Long Zhao; Yu Li Wang; Hua Shao; Li Da Tang; Jian Wu Wang
2011-01-01
A series of gem-dimethyl-bearing C-glucosides were designed and synthesized as SGLT2 inhibitors, with anhydrous aluminum chloride-mediated Friedel-Crafts alkylation to construct the gem-dimethyl functionality being the key step. The in vivo anti-hyperglycemic activity was evaluated with mice oral glucose tolerance test (OGTT), and all the synthesized compounds showed significant but less potent anti-hyperglycemic activity than the positive control dapagliflozin.
Space-bounded communication complexity
DEFF Research Database (Denmark)
Brody, Joshua Eric; Chen, Shiteng; Papakonstantinou, Periklis A.
2013-01-01
In the past thirty years, Communication Complexity has emerged as a foundational tool to proving lower bounds in many areas of computer science. Its power comes from its generality, but this generality comes at a price---no superlinear communication lower bound is possible, since a player may...... communicate his entire input. However, what if the players are limited in their ability to recall parts of their interaction? We introduce memory models for 2-party communication complexity. Our general model is as follows: two computationally unrestricted players, Alice and Bob, each have s(n) bits of memory....... When a player receives a bit of communication, he "compresses" his state. This compression may be an arbitrary function of his current memory contents, his input, and the bit of communication just received; the only restriction is that the compression must return at most s(n) bits. We obtain memory...
Entropy bounds for uncollapsed rotating bodies
Abreu, Gabriel
2010-01-01
Entropy bounds in black hole physics, based on a wide variety of different approaches, have had a long and distinguished history. Recently the current authors have turned attention to uncollapsed systems and obtained a robust entropy bound for uncollapsed static spherically symmetric configurations. In the current article we extend this bound to rotating systems. This extension is less simple than one might at first suppose. Purely classically, (using only classical general relativity and basic thermodynamics), it is possible to show that the entropy of uncollapsed matter inside a region enclosed by a surface of area A is bounded from above by S = max kappa(FIDOs) / (2 pi). Thus, using only classical general relativity, basic thermodynamics, and the Unruh effect, we are able to argue that for uncollapsed matter S <= {1/2} A.
Lee, Yu Jin; Suh, Han Na; Han, Ho Jae
2009-06-01
Recent studies demonstrated that endoplasmic reticulum (ER) stress regulates glucose homeostasis and that ER stress preconditioning which induces an adaptive, protective unfolded protein response (UPR) offers cytoprotection against nephrotoxins. Thus the aim of the present study was to use renal proximal tubule cells (PTCs) to further elucidate the link between the BSA-induced ER stress and alpha-methyl-d-glucopyranoside (alpha-MG) uptake and to identify related signaling pathways. Among ER stress inducers such as high glucose, BSA, H2O2, or tumicamycin, BSA pretreatment ameliorated the reduction of Na(+)-glucose cotransporter (SGLT) expression and alpha-MG uptake by gentamicin or cyclosporine A. Immunofluorescence studies revealed that BSA (10 mg/ml) stimulated the expression of glucose-regulated protein 78 (GRP78), an ER stress biomarker. In addition, BSA increased levels of GRP78 protein expression and eukaryotic initiation factor 2alpha (eIF2alpha) phosphorylation in a time-dependent manner. Furthermore, transfection with a GRP78-specific small interfering RNA (siRNA) inhibited BSA-stimulated SGLT expression and alpha-MG uptake. In experiments designed to unravel the mechanisms underlying BSA-induced ER stress, BSA stimulated the production of cellular reactive oxygen species (ROS), and antioxidants such as ascorbic acid or N-acetylcysteine (NAC) blocked BSA-induced increases in GRP78 activation, eIF2alpha phosphorylation, SGLT expression, and alpha-MG uptake. Moreover, the cells upregulated peroxisome proliferator-activated receptor-gamma (PPARgamma) mRNA levels in response to BSA or troglitazone (a PPARgamma agonist), but BSA was ineffective in the presence of GW9662 (a PPARgamma antagonist). In addition, both BSA and troglitazone stimulated GRP78 and eIF2alpha activation, SGLT expression, and alpha-MG uptake, whereas GW9662 inhibited the effects of BSA. BSA also stimulated phosphorylation of JNK and NF-kappaB, and GW9662 or GRP78 siRNA attenuated this
Suh, Han Na; Lee, Yu Jin; Kim, Mi Ok; Ryu, Jung Min; Han, Ho Jae
2014-10-01
The aim of this study is to determine whether GlcN could recover the endoplasmic reticulum (ER) stress-induced dysfunction of Na(+) /glucose cotransporter (SGLT) in renal proximal tubule cells (PTCs) under hypoxia. With the rabbit model, the renal ischemia induced tubulointerstitial abnormalities and decreased SGLTs expression in tubular brush-border, which were recovered by GlcN. Thus, the protective mechanism of GlcN against renal ischemia was being examined by using PTCs. Hypoxia decreased the level of protein O-GlcNAc and the expression of O-GlcNAc transferase (OGT) while increased O-GlcNAcase (OGA) and these were reversed by GlcN. Hypoxia also decreased the expression of SGLTs (SGLT1 and 2) and [(14) C]-α-methyl-D-glucopyranoside (α-MG) uptake which were recovered by GlcN and PUGNAc (OGA inhibitor). Hypoxia enhanced reactive oxygen species (ROS) and then ER stress proteins, glucose-regulated protein 78 (GRP78), and C/EBP-homologous protein (CHOP). However, the expression of GRP78 increased till 6 h and then decreased whereas CHOP increased gradually. Moreover, decreased GRP78 and increased CHOP were reversed by NAC (antioxidant) and GlcN. GlcN ameliorated hypoxia-induced decrease of O-GlcNAc modification of Sp1 but OGT or Sp1 siRNAs blocked the recovery effect of GlcN on SGLT expression and α-MG uptake. In addition, hypoxia-decreased GRP78 and HIF-1α expression was reversed by GlcN but OGT siRNA or Sp1 siRNA ameliorated the effect of GlcN. When PTCs were transfected with GRP78 siRNA or HIF-1α siRNA, SGLT expression and α-MG uptake was decreased. Taken together, these data suggest that GlcN-induced O-GlcNAc modified Sp1 with stimulating GRP78 and HIF-1α activity ameliorate hypoxia-induced SGLT dysfunction in renal PTCs. J. Cell. Physiol. 229: 1557-1568, 2014. © 2014 Wiley Periodicals, Inc.
Hoyer, Paul
2016-01-01
Even a first approximation of bound states requires contributions of all powers in the coupling. This means that the concept of "lowest order bound state" needs to be defined. In these lectures I discuss the "Born" (no loop, lowest order in $\\hbar$) approximation. Born level states are bound by gauge fields which satisfy the classical field equations. As a check of the method, Positronium states of any momentum are determined as eigenstates of the QED Hamiltonian, quantized at equal time. Analogously, states bound by a strong external field $A^\\mu(\\xv)$ are found as eigenstates of the Dirac Hamiltonian. Their Fock states have dynamically created $e^+e^-$ pairs, whose distribution is determined by the Dirac wave function. The linear potential of $D=1+1$ dimensions confines electrons but repels positrons. As a result, the mass spectrum is continuous and the wave functions have features of both bound states and plane waves. The classical solutions of Gauss' law are explored for hadrons in QCD. A non-vanishing bo...
Endurance bounds of aerial systems
Harrington, Aaron M.; Kroninger, Christopher M.
2014-06-01
Within the past few years micro aerial vehicles (MAVs) have received much more attention and are starting to proliferate into military as well as civilian roles. However, one of the major drawbacks for this technology currently, has been their poor endurance, usually below 10 minutes. This is a direct result of the inefficiencies inherent in their design. Often times, designers do not consider the various components in the vehicle design and match their performance to the desired mission for the vehicle. These vehicles lack a prescribed set of design guidelines or empirically derived design equations which often limits their design to selection of commercial off-the-shelf components without proper consideration of their affect on vehicle performance. In the current study, the design space for different vehicle configurations has been examined including insect flapping, avian flapping, rotary wing, and fixed wing, and their performance bounds are established. The propulsion system typical of a rotary wing vehicle is analyzed to establish current baselines for efficiency of vehicles at this scale. The power draw from communications is analyzed to determine its impact on vehicle performance. Finally, a representative fixed wing MAV is examined and the effects of adaptive structures as a means for increasing vehicle endurance and range are examined. This paper seeks to establish the performance bounds for micro air vehicles and establish a path forward for future designs so that efficiency may be maximized.
Information, Utility & Bounded Rationality
Ortega, Pedro A
2011-01-01
Perfectly rational decision-makers maximize expected utility, but crucially ignore the resource costs incurred when determining optimal actions. Here we employ an axiomatic framework for bounded rational decision-making based on a thermodynamic interpretation of resource costs as information costs. This leads to a variational "free utility" principle akin to thermodynamical free energy that trades off utility and information costs. We show that bounded optimal control solutions can be derived from this variational principle, which leads in general to stochastic policies. Furthermore, we show that risk-sensitive and robust (minimax) control schemes fall out naturally from this framework if the environment is considered as a bounded rational and perfectly rational opponent, respectively. When resource costs are ignored, the maximum expected utility principle is recovered.
Bounded Computational Capacity Equilibrium
Hernandez, Penelope
2010-01-01
We study repeated games played by players with bounded computational power, where, in contrast to Abreu and Rubisntein (1988), the memory is costly. We prove a folk theorem: the limit set of equilibrium payoffs in mixed strategies, as the cost of memory goes to 0, includes the set of feasible and individually rational payoffs. This result stands in sharp contrast to Abreu and Rubisntein (1988), who proved that when memory is free, the set of equilibrium payoffs in repeated games played by players with bounded computational power is a strict subset of the set of feasible and individually rational payoffs. Our result emphasizes the role of memory cost and of mixing when players have bounded computational power.
Bachoc, Christine; Cohen, Gerard; Sole, Patrick; Tchamkerten, Aslan
2010-01-01
The maximum size of a binary code is studied as a function of its length N, minimum distance D, and minimum codeword weight W. This function B(N,D,W) is first characterized in terms of its exponential growth rate in the limit as N tends to infinity for fixed d=D/N and w=W/N. The exponential growth rate of B(N,D,W) is shown to be equal to the exponential growth rate of A(N,D) for w <= 1/2, and equal to the exponential growth rate of A(N,D,W) for 1/2< w <= 1. Second, analytic and numerical upper bounds on B(N,D,W) are derived using the semidefinite programming (SDP) method. These bounds yield a non-asymptotic improvement of the second Johnson bound and are tight for certain values of the parameters.
Carlson, C E; Lebed, R F; Carlson, Carl E.; Carone, Christopher D.; Lebed, Richard F.
2001-01-01
Jurco, Moller, Schraml, Schupp, and Wess have shown how to construct noncommutative SU(N) gauge theories from a consistency relation. Within this framework, we present the Feynman rules for noncommutative QCD and compute explicitly the most dangerous Lorentz-violating operator generated through radiative corrections. We find that interesting effects appear at the one-loop level, in contrast to conventional noncommutative U(N) gauge theories, leading to a stringent bound. Our results are consistent with others appearing recently in the literature that suggest collider limits are not competitive with low-energy tests of Lorentz violation for bounding the scale of spacetime noncommutativity.
Institute of Scientific and Technical Information of China (English)
杜铁奇; 郑亿; 朱灵龙; 钟为慧
2015-01-01
Sodium glucose Co-transporter 2 (SGLT2) has been a hot spot of research on the treatment for type II diabetes. Inhibiting SGLT2, which works in the kidney specially, can reduce renal glucose reab-sorption, excrete excess glucose through the urine and lower the plasma glucose. This paper briefly reviews the synthetic routes to the C-aryl glucosides sodium glucose Co-transporter 2 inhibitors on the market, such as Ipragliflozin, Empagliflozin.%钠-葡萄糖协同转运蛋白2（SGLT2）抑制剂是目前Ⅱ型糖尿病药物研究的热点之一。通过抑制这种在肾脏特异性表达的钠-葡萄糖协同转运蛋白2（SGLT2），可以减少肾脏对葡萄糖的重吸收，增加葡萄糖在尿中的排泄，从而降低血糖。本文将针对已上市的C-芳基糖苷类SGLT2抑制剂伊格列净和恩格列净的合成路线进行简要评述。
Katsuda, Yoshiaki; Sasase, Tomohiko; Tadaki, Hironobu; Mera, Yasuko; Motohashi, Yu; Kemmochi, Yusuke; Toyoda, Kaoru; Kakimoto, Kochi; Kume, Shinichi; Ohta, Takeshi
2015-01-01
The spontaneously diabetic torii (SDT) fatty rat is a new model of type 2 diabetes showing overt obesity, hyperglycemia and hyperlipidemia. With early onset of diabetes mellitus, diabetic microvascular complications, including nephropathy, peripheral neuropathy and retinopathy, are observed at young ages. In the present study, blood glucose levels of female SDT fatty rats were controlled with phlorizin, a non-selective SGLT inhibitor, to examine whether and how these complications are caused by hyperglycemia. Phlorizin treatment adequately controlled plasma glucose levels during the experiment. At 29 weeks of age, urinary albumin excretion considerably increased in SDT fatty rats. Glomerulosclerosis and tubular pathological findings also indicate diabetic nephropathy. These renal parameters tended to decrease with phlorizin; however, effects were partial. Sciatic nerve conduction velocities were significantly delayed in SDT fatty rats compared with Sprague-Dawley (SD) rats. Intraepidermal nerve fiber density, an indicator of subclinical small nerve fiber neuropathy, significantly decreased in SDT fatty rats. Retinal dysfunction (prolongation of peak latency for oscillatory potential in electroretinograms) and histopathological eye abnormalities, including retinal folding and mature cataracts were also observed. Both nerve and eye disorders were prevented with phlorizin. These findings indicate that severe hyperglycemia mainly causes diabetic complications in SDT fatty rats. However, other factors, such as hyperlipidemia and hypertension, may affect diabetic nephropathy. These characteristics of diabetic complications will become helpful in evaluating new drugs for diabetic complications using SDT fatty rats.
KATSUDA, Yoshiaki; SASASE, Tomohiko; TADAKI, Hironobu; MERA, Yasuko; MOTOHASHI, Yu; KEMMOCHI, Yusuke; TOYODA, Kaoru; KAKIMOTO, Kochi; KUME, Shinichi; OHTA, Takeshi
2015-01-01
The spontaneously diabetic torii (SDT) fatty rat is a new model of type 2 diabetes showing overt obesity, hyperglycemia and hyperlipidemia. With early onset of diabetes mellitus, diabetic microvascular complications, including nephropathy, peripheral neuropathy and retinopathy, are observed at young ages. In the present study, blood glucose levels of female SDT fatty rats were controlled with phlorizin, a non-selective SGLT inhibitor, to examine whether and how these complications are caused by hyperglycemia. Phlorizin treatment adequately controlled plasma glucose levels during the experiment. At 29 weeks of age, urinary albumin excretion considerably increased in SDT fatty rats. Glomerulosclerosis and tubular pathological findings also indicate diabetic nephropathy. These renal parameters tended to decrease with phlorizin; however, effects were partial. Sciatic nerve conduction velocities were significantly delayed in SDT fatty rats compared with Sprague-Dawley (SD) rats. Intraepidermal nerve fiber density, an indicator of subclinical small nerve fiber neuropathy, significantly decreased in SDT fatty rats. Retinal dysfunction (prolongation of peak latency for oscillatory potential in electroretinograms) and histopathological eye abnormalities, including retinal folding and mature cataracts were also observed. Both nerve and eye disorders were prevented with phlorizin. These findings indicate that severe hyperglycemia mainly causes diabetic complications in SDT fatty rats. However, other factors, such as hyperlipidemia and hypertension, may affect diabetic nephropathy. These characteristics of diabetic complications will become helpful in evaluating new drugs for diabetic complications using SDT fatty rats. PMID:25736710
Upper bounds on superpartner masses from upper bounds on the Higgs boson mass.
Cabrera, M E; Casas, J A; Delgado, A
2012-01-13
The LHC is putting bounds on the Higgs boson mass. In this Letter we use those bounds to constrain the minimal supersymmetric standard model (MSSM) parameter space using the fact that, in supersymmetry, the Higgs mass is a function of the masses of sparticles, and therefore an upper bound on the Higgs mass translates into an upper bound for the masses for superpartners. We show that, although current bounds do not constrain the MSSM parameter space from above, once the Higgs mass bound improves big regions of this parameter space will be excluded, putting upper bounds on supersymmetry (SUSY) masses. On the other hand, for the case of split-SUSY we show that, for moderate or large tanβ, the present bounds on the Higgs mass imply that the common mass for scalars cannot be greater than 10(11) GeV. We show how these bounds will evolve as LHC continues to improve the limits on the Higgs mass.
Appell, Jürgen; Merentes Díaz, Nelson José
2013-01-01
This monographis a self-contained exposition of the definition and properties of functionsof bounded variation and their various generalizations; the analytical properties of nonlinear composition operators in spaces of such functions; applications to Fourier analysis, nonlinear integral equations, and boundary value problems. The book is written for non-specialists. Every chapter closes with a list of exercises and open problems.
DEFF Research Database (Denmark)
Emiris, Ioannis Z.; Mourrain, Bernard; Tsigaridas, Elias
2010-01-01
of variables. One application is to the bitsize of the eigenvalues and eigenvectors of an integer matrix, which also yields a new proof that the problem is polynomial. We also compare against recent lower bounds on the absolute value of the root coordinates by Brownawell and Yap [5], obtained under...
On Entropy Bounds and Holography
Halyo, Edi
2009-01-01
We show that the holographic entropy bound for gravitational systems and the Bekenstein entropy bound for nongravitational systems are holographically related. Using the AdS/CFT correspondence, we find that the Bekenstein bound on the boundary is obtained from the holographic bound in the bulk by minimizing the boundary energy with respect the AdS radius or the cosmological constant. This relation may also ameliorate some problems associated with the Bekenstein bound.
Bounded Satisfiability for PCTL
Bertrand, Nathalie; Schewe, Sven
2012-01-01
While model checking PCTL for Markov chains is decidable in polynomial-time, the decidability of PCTL satisfiability, as well as its finite model property, are long standing open problems. While general satisfiability is an intriguing challenge from a purely theoretical point of view, we argue that general solutions would not be of interest to practitioners: such solutions could be too big to be implementable or even infinite. Inspired by bounded synthesis techniques, we turn to the more applied problem of seeking models of a bounded size: we restrict our search to implementable -- and therefore reasonably simple -- models. We propose a procedure to decide whether or not a given PCTL formula has an implementable model by reducing it to an SMT problem. We have implemented our techniques and found that they can be applied to the practical problem of sanity checking -- a procedure that allows a system designer to check whether their formula has an unexpectedly small model.
Reaching Fleming's dicrimination bound
Gruebl, Gebhard
2012-01-01
Any rule for identifying a quantum system's state within a set of two non-orthogonal pure states by a single measurement is flawed. It has a non-zero probability of either yielding the wrong result or leaving the query undecided. This also holds if the measurement of an observable $A$ is repeated on a finite sample of $n$ state copies. We formulate a state identification rule for such a sample. This rule's probability of giving the wrong result turns out to be bounded from above by $1/n\\delta_{A}^{2}$ with $\\delta_{A}=|_{1}-_{2}|/(\\Delta_{1}A+\\Delta_{2}A).$ A larger $\\delta_{A}$ results in a smaller upper bound. Yet, according to Fleming, $\\delta_{A}$ cannot exceed $\\tan\\theta$ with $\\theta\\in(0,\\pi/2) $ being the angle between the pure states under consideration. We demonstrate that there exist observables $A$ which reach the bound $\\tan\\theta$ and we determine all of them.
Fadini, Gian Paolo; Bonora, Benedetta Maria; Zatti, Giancarlo; Vitturi, Nicola; Iori, Elisabetta; Marescotti, Maria Cristina; Albiero, Mattia; Avogaro, Angelo
2017-04-04
Sodium-glucose co-transporter-2 inhibitors (SGLT2i) reduce glucose levels, body weight, and blood pressure, possibly resulting in cardiovascular protection. In phase III trials, SGLT2i were shown to increase HDL cholesterol. We aimed to evaluate whether the SGLT2i dapagliflozin affects HDL function in a randomized placebo-controlled trial. Thirty-three type 2 diabetic patients were randomized to receive dapagliflozin 10 mg or placebo for 12 weeks on top of their glucose lowering medications. The primary end-point was the change in cholesterol efflux capacity (CEC) from macrophages at study end versus baseline. Secondary endpoints were changes in: distribution of HDL subfractions, lipid profile, activity of enzymes that mediate HDL antioxidant properties (PON1 and ARE) and cholesterol metabolism (CETP), HbA1c, body weight and composition. Thirty-one patients completed the study, n = 16 in the placebo group and n = 15 in the dapagliflozin group. Patients randomized to dapagliflozin were older and had lower adiposity indexes, although these differences disappeared after correction for multiple testing. Therapy with dapagliflozin reduced HbA1c by 0.9% and body weight by 3.1 kg, mainly attributable to reduction of body water and lean mass. As compared to placebo, dapagliflozin reduced CEC (-6.7 ± 2.4 versus 0.3 ± 1.8%; p = 0.043), but this effect was no longer significant after adjusting for age and BMI. No change was detected in HDL cholesterol, HDL subfractions, activity of PON1, ARE, and CETP. Despite improvements in glucose control and reduction in body weight, therapy with dapagliflozin exerted no significant effect on HDL cholesterol levels and HDL functionality. Trial registration EudraCT 2014-004270-42; NCT02327039.
Energy Technology Data Exchange (ETDEWEB)
Okauchi, Seizo, E-mail: okauchi@med.kawasaki-m.ac.jp; Shimoda, Masashi; Obata, Atsushi; Kimura, Tomohiko; Hirukawa, Hidenori; Kohara, Kenji; Mune, Tomoatsu; Kaku, Kohei; Kaneto, Hideaki
2016-02-12
It is well known that Sodium-Glucose Co-transporter 2 (SGLT2) inhibitors, new hypoglycemic agents, improve glycemic control by increasing urine glucose excretion, but it remained unclear how they exert protective effects on pancreatic β-cells. In this study, we examined the effects of SGLT2 inhibitor luseogliflozin on β-cell function and mass using obese type 2 diabetic db/db mice. Ten-week-old male diabetic db/db mice were treated with luseogliflozin 0.0025% or 0.01% in chow (Luse 0.0025% or Luse 0.01%) or vehicle (control) for 4 weeks. Urinary glucose excretion was increased in Luse groups (0.0025% and 0.01%) compared to control mice 3 days after the intervention. Fasting blood glucose levels were significantly lower in mice treated with Luse compared to control mice. Fasting serum insulin concentrations were significantly higher in mice treated with Luse compared to control mice. Triglyceride levels tended to be lower in Luse groups compared to control mice. In immunohistochemical study using pancreas tissues, β-cell mass was larger in Luse groups compared to control group which was due to the increase of β-cell proliferation and decrease of β-cell apoptosis. Furthermore, in gene analysis using isolated islets, insulin 1, insulin 2, MafA, PDX-1 and GLUT2 gene expression levels were significantly higher in Luse groups compared to control group. In contrast, expression levels of fibrosis-related gene such as TGFβ, fibronectin, collagen I and collagen III were significantly lower in Luse groups. In conclusion, SGLT2 inhibitor luseogliflozin ameliorates glycemic control and thus exerts protective effects on pancreatic β-cell mass and function. - Highlights: • SGLT2 inhibitor luseogliflozin ameliorates glycemic control in db/db mice. • Luseogliflozin increases β-cell proliferation and decreases β-cell apoptosis. • Luseogliflozin preserves various β-cell-specific gene expression. • Luseogliflozin decreases various fibrosis-related factors in db
Spatially Adaptive Intensity Bounds for Image Restoration
Directory of Open Access Journals (Sweden)
Kaaren L. May
2003-11-01
Full Text Available Spatially-adaptive intensity bounds on the image estimate are shown to be an effective means of regularising the ill-posed image restoration problem. For blind restoration, the local intensity constraints also help to further define the solution, thereby reducing the number of multiple solutions and local minima. The bounds are defined in terms of the local statistics of the image estimate and a control parameter which determines the scale of the bounds. Guidelines for choosing this parameter are developed in the context of classical (nonblind image restoration. The intensity bounds are applied by means of the gradient projection method, and conditions for convergence are derived when the bounds are refined using the current image estimate. Based on this method, a new alternating constrained minimisation approach is proposed for blind image restoration. On the basis of the experimental results provided, it is found that local intensity bounds offer a simple, flexible method of constraining both the nonblind and blind restoration problems.
BOUNDING PYRAMIDS AND BOUNDING CONES FOR TRIANGULAR BEZIER SURFACES
Institute of Scientific and Technical Information of China (English)
Jian-song Deng; Fa-lai Chen; Li-li Wang
2000-01-01
This paper describes practical approaches on how to construct bounding pyramids and bounding cones for triangular Bézier surfaces. Examples are provided to illustrate the process of construction and comparison is made between various surface bounding volumes. Furthermore, as a starting point for the construction,we provide a way to compute hodographs of triangular Bézier surfaces and improve the algorithm for computing the bounding cone of a set of vectors.
Lower bounds on Q of some dipole shapes
DEFF Research Database (Denmark)
Kim, Oleksiy S.
2016-01-01
The lower bound on the radiation Q of an arbitrary electrically small antenna shape can be determined by finding the optimal electric current density on the exterior surface of the shape, such that the Q of this current radiating in free space is minimized, and then augmenting it with a magnetic...... current density cancelling the fields inside the shape's surface. The Q of these coupled electric and magnetic currents radiating in free space is the lower bound on Q for the given shape. The approach is exemplified and its general applicability is substantiated by computing the lower bounds...
Critical SQG in bounded domains
Constantin, Peter; Ignatova, Mihaela
2016-01-01
We consider the critical dissipative SQG equation in bounded domains, with the square root of the Dirichlet Laplacian dissipation. We prove global a priori interior $C^{\\alpha}$ and Lipschitz bounds for large data.
Energy Technology Data Exchange (ETDEWEB)
Maldacena, Juan [School of Natural Sciences, Institute for Advanced Study,1 Einstein Drive, Princeton, NJ (United States); Shenker, Stephen H. [Stanford Institute for Theoretical Physics and Department of Physics, Stanford University,382 Via Pueblo Mall, Stanford, CA (United States); Stanford, Douglas [School of Natural Sciences, Institute for Advanced Study,1 Einstein Drive, Princeton, NJ (United States)
2016-08-17
We conjecture a sharp bound on the rate of growth of chaos in thermal quantum systems with a large number of degrees of freedom. Chaos can be diagnosed using an out-of-time-order correlation function closely related to the commutator of operators separated in time. We conjecture that the influence of chaos on this correlator can develop no faster than exponentially, with Lyapunov exponent λ{sub L}≤2πk{sub B}T/ℏ. We give a precise mathematical argument, based on plausible physical assumptions, establishing this conjecture.
DEFF Research Database (Denmark)
Faupin, Jeremy; Møller, Jacob Schach; Skibsted, Erik
2011-01-01
We study regularity of bound states pertaining to embedded eigenvalues of a self-adjoint operator H, with respect to an auxiliary operator A that is conjugate to H in the sense of Mourre. We work within the framework of singular Mourre theory which enables us to deal with confined massless Pauli–......–Fierz models, our primary example, and many-body AC-Stark Hamiltonians. In the simpler context of regular Mourre theory, our results boil down to an improvement of results obtained recently in [8, 9]....
Maldacena, Juan; Stanford, Douglas
2015-01-01
We conjecture a sharp bound on the rate of growth of chaos in thermal quantum systems with a large number of degrees of freedom. Chaos can be diagnosed using an out-of-time-order correlation function closely related to the commutator of operators separated in time. We conjecture that the influence of chaos on this correlator can develop no faster than exponentially, with Lyapunov exponent $\\lambda_L \\le 2 \\pi k_B T/\\hbar$. We give a precise mathematical argument, based on plausible physical assumptions, establishing this conjecture.
Spectral computations for bounded operators
Ahues, Mario; Limaye, Balmohan
2001-01-01
Exact eigenvalues, eigenvectors, and principal vectors of operators with infinite dimensional ranges can rarely be found. Therefore, one must approximate such operators by finite rank operators, then solve the original eigenvalue problem approximately. Serving as both an outstanding text for graduate students and as a source of current results for research scientists, Spectral Computations for Bounded Operators addresses the issue of solving eigenvalue problems for operators on infinite dimensional spaces. From a review of classical spectral theory through concrete approximation techniques to finite dimensional situations that can be implemented on a computer, this volume illustrates the marriage of pure and applied mathematics. It contains a variety of recent developments, including a new type of approximation that encompasses a variety of approximation methods but is simple to verify in practice. It also suggests a new stopping criterion for the QR Method and outlines advances in both the iterative refineme...
Delay Bounds for Multiclass FIFO
Jiang, Yuming; Misra, Vishal
2016-01-01
FIFO is perhaps the simplest scheduling discipline. For single-class FIFO, its delay guarantee performance has been extensively studied: The well-known results include a stochastic delay bound for $GI/GI/1$ by Kingman and a deterministic delay bound for $D/D/1$ by Cruz. However, for multiclass FIFO, few such results are available. To fill the gap, we prove delay bounds for multiclass FIFO in this work, considering both deterministic and stochastic cases. Specifically, delay bounds are present...
DEFF Research Database (Denmark)
Nielson, Hanne Riis; Nielson, Flemming
1992-01-01
they obtain a quadratic bound. These bounds are shown to be tight. Specializing the case of strict and additive functions to functionals of a form that would correspond to iterative programs they show that a linear bound is tight. This is related to several analyses studied in the literature (including...
Error bounds for set inclusions
Institute of Scientific and Technical Information of China (English)
ZHENG; Xiyin(郑喜印)
2003-01-01
A variant of Robinson-Ursescu Theorem is given in normed spaces. Several error bound theorems for convex inclusions are proved and in particular a positive answer to Li and Singer's conjecture is given under weaker assumption than the assumption required in their conjecture. Perturbation error bounds are also studied. As applications, we study error bounds for convex inequality systems.
Multifunctions of bounded variation
Vinter, R. B.
2016-02-01
Consider control systems described by a differential equation with a control term or, more generally, by a differential inclusion with velocity set F (t , x). Certain properties of state trajectories can be derived when it is assumed that F (t , x) is merely measurable w.r.t. the time variable t. But sometimes a refined analysis requires the imposition of stronger hypotheses regarding the time dependence. Stronger forms of necessary conditions for minimizing state trajectories can be derived, for example, when F (t , x) is Lipschitz continuous w.r.t. time. It has recently become apparent that significant addition properties of state trajectories can still be derived, when the Lipschitz continuity hypothesis is replaced by the weaker requirement that F (t , x) has bounded variation w.r.t. time. This paper introduces a new concept of multifunctions F (t , x) that have bounded variation w.r.t. time near a given state trajectory, of special relevance to control. We provide an application to sensitivity analysis.
Kaneto, Hideaki; Obata, Atsushi; Shimoda, Masashi; Kimura, Tomohiko; Hirukawa, Hidenori; Okauchi, Seizo; Matsuoka, Taka-Aki; Kaku, Kohei
2016-01-01
Pancreatic β-cell dysfunction and insulin resistance are the main characteristics of type 2 diabetes. Chronic exposure of β-cells to hyperglycemia leads to the deterioration of β-cell function. Such phenomena are well known as pancreatic β-cell glucose toxicity. MafA, a strong transactivator of insulin gene, is particularly important for the maintenance of mature β-cell function, but its expression level is significantly reduced under diabetic conditions which is likely associated with β-cell failure. Reduction of incretin receptor expression level in β-cells in diabetes is also likely associated with β-cell failure. On the other hand, incretin-related drugs and sodium-glucose co-transporter 2 (SGLT2) inhibitors are promising diabetes therapy based on the mechanism for pancreatic β-cell glucose toxicity. Indeed, it was shown that incretin-related drugs exerted protective effects on β-cells through the augmentation of IRS-2 expression especially in the presence of pioglitazone. It was also shown that incretin-related drug and/or pioglitazone exerted more protective effects on β-cells at the early stage of diabetes compared to the advanced stage. SGLT2 inhibitors, new hypoglycemic agents, also exert beneficial effects for the protection of pancreatic β-cells as well as for the reduction of insulin resistance in various insulin target tissues. Taken together, it is important to select appropriate therapy based on the molecular mechanism for glucose toxicity.
A Proof of the Conformal Collider Bounds
Hofman, Diego M; Meltzer, David; Poland, David; Rejon-Barrera, Fernando
2016-01-01
In this paper, we prove that the "conformal collider bounds" originally proposed by Hofman and Maldacena hold for any unitary parity-preserving conformal field theory (CFT) with a unique stress tensor in spacetime dimensions larger than 2. In particular this implies that the ratio of central charges for a unitary 4d CFT lies in the interval $\\frac{31}{18} \\geq \\frac{a}{c} \\geq \\frac{1}{3}$. For superconformal theories this is further reduced to $\\frac{3}{2} \\geq \\frac{a}{c} \\geq \\frac{1}{2}$. The proof relies only on CFT first principles - in particular, bootstrap methods - and thus constitutes the first complete field theory proof of these bounds. We further elaborate on similar bounds for non-conserved currents and relate them to results obtained recently from deep inelastic scattering.
Nowak, K.; Kästner, M.; Miltner, A.
2009-04-01
During degradation of organic pollutants in soil, metabolites, microbial biomass, CO2and "bound" residues ("non-extractable" residues in soil organic matter) are formed. Enhanced transformation of these contaminants into "bound" residues has been proposed as an alternative remediation method for polluted soils. However, this kind of residues may pose a potential risk for the environment due to their chemical structure and possible remobilization under different conditions. Therefore particular attention is given actually to "bound" residues. Part of these non-extractable residues may be "biogenic," because microorganisms use the carbon from the pollutant to form their biomass components (fatty acids, amino acids, amino sugars), which subsequently may be incorporated into soil organic matter. Furthermore, the CO2 originating from mineralization of xenobiotics, can be re-assimilated by microorganisms and also incorporated into "biogenic residue". The hazard posed by "bound" residues may be overestimated because they are "biogenic" (contain microbial fatty acids and amino acids). The knowledge about the pathways of "biogenic residue" formation is necessary for a proper assessment of the fate of tested pollutants and their turnover in the soil environment. Moreover, these data are needed to establish the realistic degradation rates of the contaminants in soil. The main objectives of this study are: to quantify the extent of "biogenic residue" (fatty acids, amino acids, amino sugars) formation during the degradation of a model pollutant (2,4-dichlorophenoxyacetic acid = 2,4-D) and during CO2 assimilation by microorganisms and to evaluate which components are mainly incorporated into "bound" residues. To investigate the extent of "biogenic residue" formation in soil during the degradation of 2,4-D, experiments with either 14C-U-ring and 13C6-2,4-D or carboxyl-14C 2,4-D were performed. The incubation experiments were performed according to OECD test guideline 307, in the
Directory of Open Access Journals (Sweden)
Hotimah Masdan Salim
2016-10-01
Full Text Available Background: Endothelial dysfunction caused by increased oxidative stress is a critical initiator of macro- and micro-vascular disease development in diabetic patients. Ipragliflozin, a selective sodium glucose co-transporter 2 (SGLT2 inhibitor, offers a novel approach for the treatment of diabetes by enhancing urinary glucose excretion. The aim of the present study was to examine whether ipragliflozin attenuates endothelial dysfunction in diabetic mice.Methods: Eight-week-old male C57BL/6 mice were treated with streptozotocin (150 mg/kg by a single intraperitoneal injection to induce diabetes mellitus. At three days of injection, ipragliflozin (3 mg/kg/day was administered via gavage for 3 weeks. Vascular function was assessed by isometric tension recording. Human umbilical endothelial cells (HUVEC were used for in vitro experiments. RNA and protein expression were examined by quantitative RT-PCR (qPCR and western blot, respectively. Oxidative stress was determined by measuring urine 8-hydroxy-2'-deoxyguanosine (8-OHdG level.Results: Ipragliflozin administration significantly reduced blood glucose level (P<0.01 and attenuated the impairment of endothelial function in diabetic mice, as determined by acetylcholine-dependent vasodilation (P<0.001. Ipragliflozin did not alter metabolic parameters such as body weight and food intake. Ipragliflozin administration ameliorated impaired phosphorylation of Akt and eNOSSer1177 in the abdominal aorta and reduced reactive oxygen species generation as determined by urinary excretion of 8-OHdG in diabetic mice. Furthermore, qPCR analyses demonstrated that ipragliflozin decreased the expression of inflammatory molecules (e.g.; MCP-1, VCAM-1 and ICAM-1 in the abdominal aorta (P<0.05, respectively. In in vitro studies, incubation with methylglyoxal, one of the advanced glycation end products, significantly impaired phosphorylation of Akt and eNOSSer1177 (P<0.01, respectively and increased the expression of MCP-1
Directory of Open Access Journals (Sweden)
Lubin Xu
2017-06-01
Full Text Available Aim To evaluate the effects of sodium-glucose co-transporter 2 (SGLT2 inhibition on renal function and albuminuria in patients with type 2 diabetes. Methods We conducted systematic searches of PubMed, Embase and Cochrane Central Register of Controlled Trials up to June 2016 and included randomized controlled trials of SGLT2 inhibitors in adult type 2 diabetic patients reporting estimated glomerular filtration rate (eGFR and/or urine albumin/creatinine ratio (ACR changes. Data were synthesized using the random-effects model. Results Forty-seven studies with 22,843 participants were included. SGLT2 inhibition was not associated with a significant change in eGFR in general (weighted mean difference (WMD, −0.33 ml/min per 1.73 m2, 95% CI [−0.90 to 0.23] or in patients with chronic kidney disease (CKD (WMD −0.78 ml/min per 1.73 m2, 95% CI [−2.52 to 0.97]. SGLT2 inhibition was associated with eGFR reduction in short-term trials (WMD −0.98 ml/min per 1.73 m2, 95% CI [−1.42 to −0.54], and with eGFR preservation in long-term trials (WMD 2.01 ml/min per 1.73 m2, 95% CI [0.86 to 3.16]. Urine ACR reduction after SGLT2 inhibition was not statistically significant in type 2 diabetic patients in general (WMD −7.24 mg/g, 95% CI [−15.54 to 1.06], but was significant in patients with CKD (WMD −107.35 mg/g, 95% CI [−192.53 to −22.18]. Conclusions SGLT2 inhibition was not associated with significant changes in eGFR in patients with type 2 diabetes, likely resulting from a mixture of an initial reduction of eGFR and long-term renal function preservation. SGLT2 inhibition was associated with statistically significant albuminuria reduction in type 2 diabetic patients with CKD.
Efficacy, safety and regulatory status of SGLT2 inhibitors: focus on canagliflozin
Haas, B; Eckstein, N; Pfeifer, V; Mayer, P; Hass, M D S
2014-01-01
Prevalence of diabetes mellitus is inc6reasing, with a burden of 382 million patients worldwide at present (more than the entire US population). The International Diabetes Federation anticipates an increase up to 592 million patients by 2035. Another major problem arises from the fact that just 50% of patients with type 2 diabetes mellitus are at target glycaemic control with currently available medications. Therefore, a clear need for new therapies that aim to optimize glycaemic control becomes evident. Renal sodium-linked glucose transporter 2 inhibitors are new antidiabetic drugs with an insulin-independent mechanism of action. They pose one remarkable advantage compared with already established antidiabetics: increasing urinary glucose excretion without inducing hypoglycaemia, thereby promoting body weight reduction due to loss of ~300 kcal per day. This review focuses on canagliflozin, which was the first successful compound of this class to be approved by both the US Food and Drug Administration and the European Medicines Agency in 2013. Clinical trials showed promising results: enhancing glycaemic control was paralleled by reducing body weight and systolic and diastolic blood pressure. Nevertheless, some safety concerns remain, such as genital mycotic infections, urinary tract infections and cardiovascular risks in vulnerable patients, which will be closely monitored in several post-authorization safety studies. PMID:25365416
Bounding approaches to system identification
Norton, John; Piet-Lahanier, Hélène; Walter, Éric
1996-01-01
In response to the growing interest in bounding error approaches, the editors of this volume offer the first collection of papers to describe advances in techniques and applications of bounding of the parameters, or state variables, of uncertain dynamical systems. Contributors explore the application of the bounding approach as an alternative to the probabilistic analysis of such systems, relating its importance to robust control-system design.
On functions of bounded variation
Aistleitner, Christoph; Pausinger, Florian; Svane, Anne Marie; Tichy, Robert F.
2015-01-01
The recently introduced concept of $\\mathcal{D}$-variation unifies previous concepts of variation of multivariate functions. In this paper, we give an affirmative answer to the open question from Pausinger \\& Svane (J. Complexity, 2014) whether every function of bounded Hardy--Krause variation is Borel measurable and has bounded $\\mathcal{D}$-variation. Moreover, we show that the space of functions of bounded $\\mathcal{D}$-variation can be turned into a commutative Banach algebra.
Bukh, Boris
2011-01-01
In 2008, Bukh, Matousek, and Nivasch conjectured that for every n-point set S in R^d and every k, 0 <= k <= d-1, there exists a k-flat f in R^d (a "centerflat") that lies at "depth" (k+1) n / (k+d+1) - O(1) in S, in the sense that every halfspace that contains f contains at least that many points of S. This claim is true and tight for k=0 (this is Rado's centerpoint theorem), as well as for k = d-1 (trivial). Bukh et al. showed the existence of a (d-2)-flat at depth (d-1) n / (2d-1) - O(1) (the case k = d-2). In this paper we concentrate on the case k=1 (the case of "centerlines"), in which the conjectured value for the leading constant is 2/(d+2). We prove that 2/(d+2) is an *upper bound* for the leading constant. Specifically, we show that for every fixed d and every n there exists an n-point set in R^d for which no line in R^d lies at depth larger than 2n/(d+2) + o(n). This point set is the "stretched grid"---a set which has been previously used by Bukh et al. for other related purposes.
Bounds on tau neutrino magnetic moment and charge radius from Super-K and SNO observations
Joshipura, A S; Joshipura, Anjan S.; Mohanty, Subhendra
2001-01-01
Neutrinos can scatter electrons in water detectors through their magnetic moments and charge radii in addition to the charged and neutral currents channels. The recent solar neutrino charged current event rates announced by SNO with the earlier solar and atmospheric neutrino observations from Super-Kamiokande allows us to put upper bounds of $\\mu < 10^{-31} cm^2$ on the neutrino charge radii. For the electron and muon neutrinos these bounds are comparable with existing bounds but for tau neutrinos these bounds are three orders of magnitude more stringent than earlier terrestrial bounds. These bounds are independent of any specific model of neutrino oscillations.
Institute of Scientific and Technical Information of China (English)
LIU Li-Guo; TIAN Cheng-Lin; CHEN Ping-Xing; YUAN Nai-Chang
2009-01-01
We derive an analytical lower bound on the concurrence for bipartite quantum systems with an improved computable cross norm or realignment criterion and an improved positive partial transpose criterion respectively.Furthermore we demonstrate that our bound is better than that obtained from the local uncertainty relations criterion with optimal local orthogonal observables which is known as one of the best estimations of concurrence.
Bounds for Asian basket options
Deelstra, Griselda; Diallo, Ibrahima; Vanmaele, Michèle
2008-09-01
In this paper we propose pricing bounds for European-style discrete arithmetic Asian basket options in a Black and Scholes framework. We start from methods used for basket options and Asian options. First, we use the general approach for deriving upper and lower bounds for stop-loss premia of sums of non-independent random variables as in Kaas et al. [Upper and lower bounds for sums of random variables, Insurance Math. Econom. 27 (2000) 151-168] or Dhaene et al. [The concept of comonotonicity in actuarial science and finance: theory, Insurance Math. Econom. 31(1) (2002) 3-33]. We generalize the methods in Deelstra et al. [Pricing of arithmetic basket options by conditioning, Insurance Math. Econom. 34 (2004) 55-57] and Vanmaele et al. [Bounds for the price of discrete sampled arithmetic Asian options, J. Comput. Appl. Math. 185(1) (2006) 51-90]. Afterwards we show how to derive an analytical closed-form expression for a lower bound in the non-comonotonic case. Finally, we derive upper bounds for Asian basket options by applying techniques as in Thompson [Fast narrow bounds on the value of Asian options, Working Paper, University of Cambridge, 1999] and Lord [Partially exact and bounded approximations for arithmetic Asian options, J. Comput. Finance 10 (2) (2006) 1-52]. Numerical results are included and on the basis of our numerical tests, we explain which method we recommend depending on moneyness and time-to-maturity.
Anaphoric Pronouns and Bound Variables
Wasow, Thomas
1975-01-01
Deals with certain problems inherent in deriving anaphoric pronouns from bound variables. Syntactic rules applied to determine anaphora relations cannot be applied if anaphoric pronouns and their antecedents have identical underlying forms. An approach to anaphora which preserves some advantages of the bound-variable theory without the problems is…
Asynchronous Bounded Expected Delay Networks
Bakhshi, Rena; Fokkink, Wan; Pang, Jun
2010-01-01
The commonly used asynchronous bounded delay (ABD) network models assume a fixed bound on message delay. We propose a probabilistic network model, called asynchronous bounded expected delay (ABE) model. Instead of a strict bound, the ABE model requires only a bound on the expected message delay. While the conditions of ABD networks restrict the set of possible executions, in ABE networks all asynchronous executions are possible, but executions with extremely long delays are less probable. In contrast to ABD networks, ABE networks cannot be synchronised efficiently. At the example of an election algorithm, we show that the minimal assumptions of ABE networks are sufficient for the development of efficient algorithms. For anonymous, unidirectional ABE rings of known size N we devise a probabilistic leader election algorithm having average message and time complexity O(N).
Bounded relative motion under zonal harmonics perturbations
Baresi, Nicola; Scheeres, Daniel J.
2017-04-01
The problem of finding natural bounded relative trajectories between the different units of a distributed space system is of great interest to the astrodynamics community. This is because most popular initialization methods still fail to establish long-term bounded relative motion when gravitational perturbations are involved. Recent numerical searches based on dynamical systems theory and ergodic maps have demonstrated that bounded relative trajectories not only exist but may extend up to hundreds of kilometers, i.e., well beyond the reach of currently available techniques. To remedy this, we introduce a novel approach that relies on neither linearized equations nor mean-to-osculating orbit element mappings. The proposed algorithm applies to rotationally symmetric bodies and is based on a numerical method for computing quasi-periodic invariant tori via stroboscopic maps, including extra constraints to fix the average of the nodal period and RAAN drift between two consecutive equatorial plane crossings of the quasi-periodic solutions. In this way, bounded relative trajectories of arbitrary size can be found with great accuracy as long as these are allowed by the natural dynamics and the physical constraints of the system (e.g., the surface of the gravitational attractor). This holds under any number of zonal harmonics perturbations and for arbitrary time intervals as demonstrated by numerical simulations about an Earth-like planet and the highly oblate primary of the binary asteroid (66391) 1999 KW4.
The Out-bound and In-bound Travelling Market
Institute of Scientific and Technical Information of China (English)
Emily Yu
2009-01-01
@@ As the Spring Festival of China with a long vocation of seven days nationally is approaching,more and more attention is paid to the out-bound and inn-bound trayeling market.Will people hold their pockets firmly in the"cold winter"of world-wide financial crisis,or will they grab the great discount of traveling and take a good relax?
Combining Alphas via Bounded Regression
Directory of Open Access Journals (Sweden)
Zura Kakushadze
2015-11-01
Full Text Available We give an explicit algorithm and source code for combining alpha streams via bounded regression. In practical applications, typically, there is insufficient history to compute a sample covariance matrix (SCM for a large number of alphas. To compute alpha allocation weights, one then resorts to (weighted regression over SCM principal components. Regression often produces alpha weights with insufficient diversification and/or skewed distribution against, e.g., turnover. This can be rectified by imposing bounds on alpha weights within the regression procedure. Bounded regression can also be applied to stock and other asset portfolio construction. We discuss illustrative examples.
Bounds for Certain Character Sums
Institute of Scientific and Technical Information of China (English)
杨锦; 郑志勇
2003-01-01
This paper shows a connection between exponential sums and character sums. In particular, we introduce a character sum that is an analog of the classical Kloosterman sums and establish the analogous Weil-Estermann's upper bound for it. The paper also analyzes a generalized Hardy-Littlewood example for character sums, which shows that the upper bounds given here are the best possible. The analysis makes use of local bounds for the exponential sums and character sums. The basic theorems have been previously established.
Institute of Scientific and Technical Information of China (English)
Zhi-Hong Tao; Cong-Hua Zhou; Zhong Chen; Li-Fu Wang
2007-01-01
Bounded Model Checking has been recently introduced as an efficient verification method for reactive systems.This technique reduces model checking of linear temporal logic to propositional satisfiability.In this paper we first present how quantified Boolean decision procedures can replace BDDs.We introduce a bounded model checking procedure for temporal logic CTL* which reduces model checking to the satisfiability of quantified Boolean formulas.Our new technique avoids the space blow up of BDDs, and extends the concept of bounded model checking.
Computing Constrained Cramer Rao Bounds
Tune, Paul
2012-01-01
We revisit the problem of computing submatrices of the Cram\\'er-Rao bound (CRB), which lower bounds the variance of any unbiased estimator of a vector parameter $\\vth$. We explore iterative methods that avoid direct inversion of the Fisher information matrix, which can be computationally expensive when the dimension of $\\vth$ is large. The computation of the bound is related to the quadratic matrix program, where there are highly efficient methods for solving it. We present several methods, and show that algorithms in prior work are special instances of existing optimization algorithms. Some of these methods converge to the bound monotonically, but in particular, algorithms converging non-monotonically are much faster. We then extend the work to encompass the computation of the CRB when the Fisher information matrix is singular and when the parameter $\\vth$ is subject to constraints. As an application, we consider the design of a data streaming algorithm for network measurement.
An Inequality for Bounded Functions
Kouba, Omran
2012-01-01
In this note we prove optimal inequalities for bounded functions in terms of their deviation from their mean. These results extend and generalize some known inequalities due to Thong (2011) and Perfetti (2011)
Schulz, Marc Daniel; Dusuel, Sébastien; Vidal, Julien
2016-11-01
We discuss the emergence of bound states in the low-energy spectrum of the string-net Hamiltonian in the presence of a string tension. In the ladder geometry, we show that a single bound state arises either for a finite tension or in the zero-tension limit depending on the theory considered. In the latter case, we perturbatively compute the binding energy as a function of the total quantum dimension. We also address this issue in the honeycomb lattice where the number of bound states in the topological phase depends on the total quantum dimension. Finally, the internal structure of these bound states is analyzed in the zero-tension limit.
Schulz, M D; Vidal, J
2016-01-01
We discuss the emergence of bound states in the low-energy spectrum of the string-net Hamiltonian in the presence of a string tension. In the ladder geometry, we show that a single bound state arises either for a finite tension or in the zero-tension limit depending on the theory considered. In the latter case, we perturbatively compute the binding energy as a function of the total quantum dimension. We also address this issue in the honeycomb lattice where the number of bound states in the topological phase depends on the total quantum dimension. Finally, the internal structure of these bound states is analyzed in the zero-tension limit.
Some bounds for quantum copying
Rastegin, A E
2001-01-01
We derive lower bounds on the absolute error and the relative error of an abstract copying of two-state set. We do not specify a copying transformation and a dimension of state space. Only the unitarity of quantum mechanical transformations is used. Our approach is based on the notion of angle between two states. We first prove several useful statements, simply expressed in terms of angles. We then examine a lower bound on the absolute error, that was first considered by Hillery and Buzek. Our reasonings supplement and reinforce the results, obtained by them. So, we derive more strong bounds on the absolute error, and we also consider a tradeoff between size of error and corresponding probability distributions. After that we examine a lower bound on the relative error.
Bound values for Hall conductivity of heterogeneous medium under quantum Hall effect conditions
Indian Academy of Sciences (India)
V E Arkhincheev
2008-02-01
Bound values for Hall conductivity under quantum Hall effect (QHE) conditions in inhomogeneous medium has been studied. It is shown that bound values for Hall conductivity differ from bound values for metallic conductivity. This is due to the unusual character of current percolation under quantum Hall effect conditions.
Mutual information challenges entropy bounds
Casini, H
2006-01-01
We consider some formulations of the entropy bounds at the semiclassical level. The entropy S(V) localized in a region V is divergent in quantum field theory (QFT). Instead of it we focus on the mutual information I(V,W)=S(V)+S(W)-S(V U W) between two different non-intersecting sets V and W. This is a low energy quantity, independent of the regularization scheme. In addition, the mutual information is bounded above by twice the entropy corresponding to the sets involved. Calculations of I(V,W) in QFT show that the entropy in empty space cannot be renormalized to zero, and must be actually very large. We find that this entropy due to the vacuum fluctuations violates the FMW bound in Minkowski space. The mutual information also gives a precise, cutoff independent meaning to the statement that the number of degrees of freedom increases with the volume in QFT. If the holographic bound holds, this points to the essential non locality of the physical cutoff. Violations of the Bousso bound would require conformal th...
Hemmingsen, Bianca; Krogh, Jesper; Metzendorf, Maria-Inti; Richter, Bernd
2016-04-21
Sodium-glucose cotransporter (SGLT) 2 inhibitors were recently approved as glucose-lowering interventions in people with type 2 diabetes mellitus (T2DM). Potential beneficial or harmful effects of SGLT 2 inhibitors in people at risk for the development of T2DM are unknown. To assess the effects of SGLT 2 inhibitors focusing on the prevention or delay of T2DM and its associated complications in people with impaired glucose tolerance, impaired fasting blood glucose or moderately elevated glycosylated haemoglobin A1c (HbA1c) or any combination of these. We searched the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, PubMed, EMBASE, ClinicalTrials.gov, the World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP) and reference lists of systematic reviews, articles and health technology assessment reports. We asked investigators of ongoing for information about additional trials. The date of the last search of all databases was January 2016. Randomised controlled trials (RCTs) of any duration comparing SGLT 2 inhibitors with any glucose-lowering intervention, behaviour-changing intervention, placebo or no intervention in people with impaired fasting glucose, impaired glucose tolerance, moderately elevated HbA1c or combinations of these. Two review authors read all abstracts, assessed quality and extracted data independently. We resolved discrepancies by consensus or the involvement of a third author. We could not include any RCT in this systematic review. One trial was published in two abstracts, but did not provide separate information of the participants with impaired glucose tolerance, impaired fasting glucose or both. We identified two ongoing trials, both evaluating the effects of dapagliflozin (and metformin) in people at risk for the development of type 2 diabetes and a follow-up of 24 to 26 weeks. Both trials will mainly report on surrogate outcome measures with some data on adverse effects and health
Eta nuclear bound states revisited
Friedman, E; Mareš, J
2013-01-01
The strong energy dependence of the s-wave eta-N scattering amplitude at and below threshold, as evident in coupled-channels K-matrix fits and chiral models that incorporate the S11 N*(1535) resonance, is included self consistently in eta-nuclear bound state calculations. This approach, applied recently in calculations of kaonic atoms and Kbar-nuclear bound states, is found to impose stronger constraints than ever on the onset of eta-nuclear binding, with a minimum value of Re a_{eta N} approximately 0.9 fm required to accommodate an eta-4He bound state. Binding energies and widths of eta-nuclear states are calculated within several underlying eta-N models for nuclei across the periodic table, including eta-25Mg for which some evidence was proposed in a recent COSY experiment.
Improved Range Searching Lower Bounds
DEFF Research Database (Denmark)
Larsen, Kasper Green; Nguyen, Huy L.
2012-01-01
Table of Contents -------------------------------------------------------------------------------- In this paper we present a number of improved lower bounds for range searching in the pointer machine and the group model. In the pointer machine, we prove lower bounds for the approximate simplex...... range reporting problem. In approximate simplex range reporting, points that lie within a distance of ε ⋅ Diam(s) from the border of a query simplex s, are free to be included or excluded from the output, where ε ≥ 0 is an input parameter to the range searching problem. We prove our lower bounds...... by constructing a hard input set and query set, and then invoking Chazelle and Rosenberg's [CGTA'96] general theorem on the complexity of navigation in the pointer machine. For the group model, we show that input sets and query sets that are hard for range reporting in the pointer machine (i.e. by Chazelle...
Experimental activation of bound entanglement.
Kaneda, Fumihiro; Shimizu, Ryosuke; Ishizaka, Satoshi; Mitsumori, Yasuyoshi; Kosaka, Hideo; Edamatsu, Keiichi
2012-07-27
Entanglement is one of the essential resources in quantum information and communication technology (QICT). The entanglement thus far explored and applied to QICT has been pure and distillable entanglement. Yet, there is another type of entanglement, called "bound entanglement," which is not distillable by local operations and classical communication. We demonstrate the experimental "activation" of the bound entanglement held in the four-qubit Smolin state, unleashing its immanent entanglement in distillable form, with the help of auxiliary two-qubit entanglement and local operations and classical communication. We anticipate that it opens the way to a new class of QICT applications that utilize more general classes of entanglement than ever, including bound entanglement.
Modeling agreement on bounded scales.
Vanbelle, Sophie; Lesaffre, Emmanuel
2017-01-01
Agreement is an important concept in medical and behavioral sciences, in particular in clinical decision making where disagreements possibly imply a different patient management. The concordance correlation coefficient is an appropriate measure to quantify agreement between two scorers on a quantitative scale. However, this measure is based on the first two moments, which could poorly summarize the shape of the score distribution on bounded scales. Bounded outcome scores are common in medical and behavioral sciences. Typical examples are scores obtained on visual analog scales and scores derived as the number of positive items on a questionnaire. These kinds of scores often show a non-standard distribution, like a J- or U-shape, questioning the usefulness of the concordance correlation coefficient as agreement measure. The logit-normal distribution has shown to be successful in modeling bounded outcome scores of two types: (1) when the bounded score is a coarsened version of a latent score with a logit-normal distribution on the [0,1] interval and (2) when the bounded score is a proportion with the true probability having a logit-normal distribution. In the present work, a model-based approach, based on a bivariate generalization of the logit-normal distribution, is developed in a Bayesian framework to assess the agreement on bounded scales. This method permits to directly study the impact of predictors on the concordance correlation coefficient and can be simply implemented in standard Bayesian softwares, like JAGS and WinBUGS. The performances of the new method are compared to the classical approach using simulations. Finally, the methodology is used in two different medical domains: cardiology and rheumatology.
Lower Bounds for Sparse Recovery
Ba, Khanh Do; Price, Eric; Woodruff, David P
2011-01-01
We consider the following k-sparse recovery problem: design an m x n matrix A, such that for any signal x, given Ax we can efficiently recover x' satisfying ||x-x'||_1 <= C min_{k-sparse} x"} ||x-x"||_1. It is known that there exist matrices A with this property that have only O(k log (n/k)) rows. In this paper we show that this bound is tight. Our bound holds even for the more general /randomized/ version of the problem, where A is a random variable and the recovery algorithm is required to work for any fixed x with constant probability (over A).
Variables Bounding Based Retiming Algorithm
Institute of Scientific and Technical Information of China (English)
宫宗伟; 林争辉; 陈后鹏
2002-01-01
Retiming is a technique for optimizing sequential circuits. In this paper, wediscuss this problem and propose an improved retiming algorithm based on variables bounding.Through the computation of the lower and upper bounds on variables, the algorithm can signi-ficantly reduce the number of constraints and speed up the execution of retiming. Furthermore,the elements of matrixes D and W are computed in a demand-driven way, which can reducethe capacity of memory. It is shown through the experimental results on ISCAS89 benchmarksthat our algorithm is very effective for large-scale sequential circuits.
Bounds for Completely Decomposable Jacobians
Duursma, Iwan
2010-01-01
A curve over the field of two elements with completely decomposable Jacobian is shown to have at most six rational points and genus at most 26. The bounds are sharp. The previous upper bound for the genus was 145. We also show that a curve over the field of $q$ elements with more than $q^{m/2}+1$ rational points has at least one Frobenius angle in the open interval $(\\pi/m,3\\pi/m)$. The proofs make use of the explicit formula method.
Institute of Scientific and Technical Information of China (English)
周笑犁; 孔祥峰; 张珍珍; 印遇龙
2013-01-01
Ojective To investigate the effects of soybean oligosaccharides (SBOS) on development of small intestine and absorption in weaned piglets. Method Twelve Huanjiang mini-piglets weaned at age 21 d were randomly allocated into two groups with six replicates in the feeding trial. The piglets were fed 0% or 0.5% SBOS- supplemented diet for 14 d. The plasma was collected at the end of this trail and used for measuring blood glucose. The jejunum and ileum were collected for histological analysis. The mRNA expression abundances of sodiuml glucose cotransporter (SGLT1) and glucose transporfer (GLUT2) in jejunum and ileum were determined by relative quantitative RT-PCR respectively. Results The mRNA expression of SGLT1 and GLUT2 in SBOS group had intestinal space position specificity, and their expression levels in the jejunum were higher (P<0.05) than those in ileum, as well as than the control group. SBOS increased (.P<0.05) the ratio of villus height and fossae depth of small intestine. Conclusion SBOS can promote development and nutrient absorption of small intestine in mini-piglets.%目的 研究大豆寡糖(SBOS)对小肠发育及其吸收功能的影响.方法 选用21d龄断奶的环江香猪12头,随机分为2组,每组6头,分别饲喂添加0.5％ SBOS的日粮和基础日粮,试验期14d.试验结束后采集血液,肝素抗凝,离心分离血浆,测定血糖浓度；放血处死后取空、回肠组织各两份,另一份采用于组织固定,进行形态学观察；一份利用荧光定量RT-PCR法,测定葡萄糖转运载体SGLT1和GLUT2 mRNA的表达.结果 与基础日粮组相比,SBOS组葡萄糖转运载体的表达具有肠道空间位置特异性,空肠SGLT1和GLUT2 mRNA的表达量显著高于回肠(P＜0.05)；并显著高于基础日粮组空肠的表达量(P＜0.05)；SBOS显著提高了仔猪小肠绒毛高度与隐窝深度的比值(P＜0.05).结论 SBOS能促进小肠发育,提高肠道对营养物质的吸收.
Market access through bound tariffs
DEFF Research Database (Denmark)
Sala, Davide; Schröder, Philipp J.H.; Yalcin, Erdal
2010-01-01
WTO negotiations deal predominantly with bound - besides applied - tariff rates. But, how can reductions in tariffs ceilings, i.e. tariff rates that no exporter may ever actually be confronted with, generate market access? The answer to this question relates to the effects of tariff bindings on t...
Market Access through Bound Tariffs
DEFF Research Database (Denmark)
Sala, Davide; Schröder, Philipp J.H.; Yalcin, Erdal
WTO negotiations deal predominantly with bound - besides applied - tariff rates. But, how can reductions in tariffs ceilings, i.e. tariff rates that no exporter may ever actually be confronted with, generate market access? The answer to this question relates to the effects of tariff bindings on t...
Bounded Densities and Their Derivatives
DEFF Research Database (Denmark)
Kozine, Igor; Krymsky, V.
2009-01-01
This paper describes how one can compute interval-valued statistical measures given limited information about the underlying distribution. The particular focus is on a bounded derivative of a probability density function and its combination with other available statistical evidence for computing ...
Wronskian Method for Bound States
Fernandez, Francisco M.
2011-01-01
We propose a simple and straightforward method based on Wronskians for the calculation of bound-state energies and wavefunctions of one-dimensional quantum-mechanical problems. We explicitly discuss the asymptotic behaviour of the wavefunction and show that the allowed energies make the divergent part vanish. As illustrative examples we consider…
Variational Bounds for Creeping Composites
Procházka, Petr
2010-05-01
In the paper time dependent variational bounds are derived based on Extended Hashin-Shtrikman variational principles. Direct calculation leads to explicit formulas to be presented in the text. For various mechanical properties easy coding in Excel, say, can be used and verification of accuracy for numerical procedures is available using the derived formulas.
Pieter Paul Rubens, "Prometheus Bound."
Shoemaker, Marla K.
1986-01-01
Provides a full-color reproduction of Pieter Paul Rubens' painting, "Prometheus Bound," and a lesson plan for using it with students in grades 10 through 12. The goal of the lesson is to introduce students to the techniques of design and execution used by Rubens. (JDH)
Carvalho, Catarina; MarkoviÄ, Petar; Maróti, Miklós
2007-01-01
We prove that the constraint languages invariant under a short sequence of J\\'onsson terms (containing at most three non-trivial ternary terms) are tractable by showing that they have bounded width. This improves the previous result by Kiss and Valeriote and presents some evidence that the Larose-Zadori conjecture holds in the congruence-distributive case.
Pieter Paul Rubens, "Prometheus Bound."
Shoemaker, Marla K.
1986-01-01
Provides a full-color reproduction of Pieter Paul Rubens' painting, "Prometheus Bound," and a lesson plan for using it with students in grades 10 through 12. The goal of the lesson is to introduce students to the techniques of design and execution used by Rubens. (JDH)
A Functional Calculus for Quotient Bounded Operators
Directory of Open Access Journals (Sweden)
Sorin Mirel Stoian
2006-12-01
Full Text Available If (X, P is a sequentially locally convex space, then a quotient bounded operator T beloging to QP is regular (in the sense of Waelbroeck if and only if it is a bounded element (in the sense of Allan of algebra QP. The classic functional calculus for bounded operators on Banach space is generalized for bounded elements of algebra QP.
Directory of Open Access Journals (Sweden)
Gurgle HE
2016-06-01
Full Text Available Holly E Gurgle, Karen White, Carrie McAdam-Marx Department of Pharmacotherapy, University of Utah College of Pharmacy, Salt Lake City, UT, USA Abstract: Controversy exists regarding the selection of second-line therapy for patients with type 2 diabetes mellitus (T2DM who are unable to achieve glycemic control with metformin therapy alone. Newer pharmacologic treatments for T2DM include glucagon-like peptide-1 receptor agonists and sodium–glucose cotransporter 2 inhibitors. Both the classes of medication are efficacious, exhibit positive effects on weight, and are associated with minimal risk of hypoglycemia. The purpose of this review is to compare the clinical trial and real-world effectiveness data of glucagon-like peptide-1 receptor agonists versus sodium–glucose cotransporter 2 inhibitors related to A1c reduction, weight loss, cost-effectiveness, cardiovascular outcomes, and safety in patients with T2DM. This review summarizes comparative evidence for providers who are determining which of the two classes may be the most appropriate for a specific patient. Keywords: type 2 diabetes mellitus, GLP-1 receptor agonist, SGLT2 inhibitor, A1c, weight loss, adverse effect
Shi, Jian; Zheng, Haihui; Yu, Jia; Zhu, Lijun; Yan, Tongmeng; Wu, Peng; Lu, Linlin; Wang, Ying; Hu, Ming; Liu, Zhongqiu
2016-03-01
Hydrolysis by lactase-phloridzin hydrolase (LPH) is the first and critical step in the absorption of isoflavonoid glucosides. However, the absorption characteristics of calycosin-7-O-β-d-glucoside (CG) slightly differ from other isoflavonoid glucosides. In this study, we used the rat intestinal perfusion model and performed pharmacokinetic studies and in vitro experiments to determine the factors influencing CG absorption and disposition. After oral administration of isoflavonoid glucosides, LPH was found to play minimal or no role on the hydrolysis of CG, in contrast to that of daidzin. CG was mainly transported into the small intestinal cells by sodium-dependent glucose transporter 1 (SGLT-1) as intact. This pathway could be the main mechanism underlying the high permeability of CG in the small intestine. CG was likely to be hydrolyzed in enterocytes to its aglycone calycosin by broad-specific β-glucuronides (BSβG) and glucocerebrosidase or rapidly metabolized. Calycosin was also rapidly and extensively metabolized to 3'-glucuronide in the enterocytes and liver, and the glucuronidation rates of calycosin and CG were much higher in the former. The metabolites were also transported into lumen by breast cancer resistance protein and multidrug resistance-associated protein 2. In conclusion, the enterocytes could be an important site for CG absorption, deglycosylation, and metabolism in rats. This study could contribute to the theoretical foundation and mechanism of absorption and disposition of flavonoid compounds.
Gallo, Linda A; Ward, Micheal S; Fotheringham, Amelia K; Zhuang, Aowen; Borg, Danielle J; Flemming, Nicole B; Harvie, Ben M; Kinneally, Toni L; Yeh, Shang-Ming; McCarthy, Domenica A; Koepsell, Hermann; Vallon, Volker; Pollock, Carol; Panchapakesan, Usha; Forbes, Josephine M
2016-05-26
Blood glucose control is the primary strategy to prevent complications in diabetes. At the onset of kidney disease, therapies that inhibit components of the renin angiotensin system (RAS) are also indicated, but these approaches are not wholly effective. Here, we show that once daily administration of the novel glucose lowering agent, empagliflozin, an SGLT2 inhibitor which targets the kidney to block glucose reabsorption, has the potential to improve kidney disease in type 2 diabetes. In male db/db mice, a 10-week treatment with empagliflozin attenuated the diabetes-induced upregulation of profibrotic gene markers, fibronectin and transforming-growth-factor-beta. Other molecular (collagen IV and connective tissue growth factor) and histological (tubulointerstitial total collagen and glomerular collagen IV accumulation) benefits were seen upon dual therapy with metformin. Albuminuria, urinary markers of tubule damage (kidney injury molecule-1, KIM-1 and neutrophil gelatinase-associated lipocalin, NGAL), kidney growth, and glomerulosclerosis, however, were not improved with empagliflozin or metformin, and plasma and intra-renal renin activity was enhanced with empagliflozin. In this model, blood glucose lowering with empagliflozin attenuated some molecular and histological markers of fibrosis but, as per treatment with metformin, did not provide complete renoprotection. Further research to refine the treatment regimen in type 2 diabetes and nephropathy is warranted.
Alternation-Trading Proofs, Linear Programming, and Lower Bounds
Williams, Ryan
2010-01-01
A fertile area of recent research has demonstrated concrete polynomial time lower bounds for solving natural hard problems on restricted computational models. Among these problems are Satisfiability, Vertex Cover, Hamilton Path, Mod6-SAT, Majority-of-Majority-SAT, and Tautologies, to name a few. The proofs of these lower bounds follow a certain proof-by-contradiction strategy that we call alternation-trading. An important open problem is to determine how powerful such proofs can possibly be. We propose a methodology for studying these proofs that makes them amenable to both formal analysis and automated theorem proving. We prove that the search for better lower bounds can often be turned into a problem of solving a large series of linear programming instances. Implementing a small-scale theorem prover based on this result, we extract new human-readable time lower bounds for several problems. This framework can also be used to prove concrete limitations on the current techniques.
Physics with loosely bound nuclei
Indian Academy of Sciences (India)
Chhanda Samanta
2001-08-01
The essential aspect of contemporary physics is to understand properties of nucleonic matter that constitutes the world around us. Over the years research in nuclear physics has provided strong guidance in understanding the basic principles of nuclear interactions. But, the scenario of nuclear physics changed drastically as the new generation of accelerators started providing more and more rare isotopes, which are away from the line of stability. These weakly bound nuclei are found to exhibit new forms of nuclear matter and unprecedented exotic behaviour. The low breakup thresholds of these rare nuclei are posing new challenges to both theory and experiments. Fortunately, nature has provided a few loosely bound stable nuclei that have been studied thoroughly for decades. Attempts are being made to ﬁnd a consistent picture for the unstable nuclei starting from their stable counterparts. Some signiﬁcant differences in the structure and reaction mechanisms are found.
Lower Bounds on Paraclique Density.
Hagan, Ronald D; Langston, Michael A; Wang, Kai
2016-05-11
The scientific literature teems with clique-centric clustering strategies. In this paper we analyze one such method, the paraclique algorithm. Paraclique has found practical utility in a variety of application domains, and has been successfully employed to reduce the effects of noise. Nevertheless, its formal analysis and worst-case guarantees have remained elusive. We address this issue by deriving a series of lower bounds on paraclique densities.
Wronskian method for bound states
Energy Technology Data Exchange (ETDEWEB)
Fernandez, Francisco M, E-mail: fernande@quimica.unlp.edu.ar [INIFTA (UNLP, CONICET), Division Quimica Teorica, Boulevard 113 S/N, Sucursal 4, Casilla de Correo 16, 1900 La Plata (Argentina)
2011-05-15
We propose a simple and straightforward method based on Wronskians for the calculation of bound-state energies and wavefunctions of one-dimensional quantum-mechanical problems. We explicitly discuss the asymptotic behaviour of the wavefunction and show that the allowed energies make the divergent part vanish. As illustrative examples we consider an exactly solvable model, the Gaussian potential well, and a two-well potential proposed earlier for the interpretation of the infrared spectrum of ammonia.
Bound Modes in Dielectric Microcavities
Visser, P M; Lenstra, D
2002-01-01
We demonstrate how exactly bound cavity modes can be realized in dielectric structures other than 3d photonic crystals. For a microcavity consisting of crossed anisotropic layers, we derive the cavity resonance frequencies, and spontaneous emission rates. For a dielectric structure with dissipative loss and central layer with gain, the beta factor of direct spontaneous emission into a cavity mode and the laser threshold is calculated.
Entropy Bounds in Spherical Space
Brevik, I; Odintsov, S D; Brevik, Iver; Milton, Kimball A.; Odintsov, Sergei D.
2002-01-01
Exact calculations are given for the Casimir energy for various fields in $R\\times S^3$ geometry. The Green's function method naturally gives a result in a form convenient in the high-temperature limit, while the statistical mechanical approach gives a form appropriate for low temperatures. The equivalence of these two representations is demonstrated. Some discrepancies with previous work are noted. In no case, even for ${\\cal N}=4$ SUSY, is the ratio of entropy to energy found to be bounded.
2013-03-26
... Agency Information Collection Activities; Comment Request; Upward Bound and Upward Bound Math Science... Upward Bound Math Science Annual Performance Report. OMB Control Number: 1840-NEW. Type of Review: New... under the regular Upward Bound (UB) and Upward Bound Math and Science (UBMS) Programs. The Department is...
Kim, Hyo-Sil
2011-01-01
We study the motion-planning problem for a car-like robot whose turning radius is bounded from below by one and which is allowed to move in the forward direction only (Dubins car). For two robot configurations $\\sigma, \\sigma'$, let $\\ell(\\sigma, \\sigma')$ be the shortest bounded-curvature path from $\\sigma$ to $\\sigma'$. For $d \\geq 0$, let $\\ell(d)$ be the supremum of $\\ell(\\sigma, \\sigma')$, over all pairs $(\\sigma, \\sigma')$ that are at Euclidean distance $d$. We study the function $\\dub(d) = \\ell(d) - d$, which expresses the difference between the bounded-curvature path length and the Euclidean distance of its endpoints. We show that $\\dub(d)$ decreases monotonically from $\\dub(0) = 7\\pi/3$ to $\\dub(\\ds) = 2\\pi$, and is constant for $d \\geq \\ds$. Here $\\ds \\approx 1.5874$. We describe pairs of configurations that exhibit the worst-case of $\\dub(d)$ for every distance $d$.
Daly, Ruth A
2009-01-01
Beam powers and black hole masses of 48 extended radio sources are combined to obtain lower bounds on the spins and magnetic field strengths of supermassive black holes. This is done in the context of the models of Blandford & Znajek (1977) (the 'BZ' model) and Meier (1999); a parameterization for bounds in the context of other models is suggested. The bounds obtained for very powerful classical double radio sources in the BZ model are consistent with black hole spins of order unity for sources at high redshift. The black hole spins are largest for the highest redshift sources and decrease for sources at lower redshift; the sources studied have redshifts between zero and two. Lower power radio sources associated with central dominant galaxies may have black hole spins that are significantly less than one. Combining this analysis with other results suggests that the maximum values of black hole spin associated with powerful radio galaxies decline from values of order unity at a redshift of 2 to values of o...
Bounds on Generalized Huffman Codes
Baer, Michael B
2007-01-01
New lower and upper bounds are obtained for the compression of optimal binary prefix codes according to various nonlinear codeword length objectives. Like the coding bounds for Huffman coding - which concern the traditional linear code objective of minimizing average codeword length -- these are in terms of a form of entropy and the probability of the most probable input symbol. As in Huffman coding, some upper bounds can be found using sufficient conditions for the codeword corresponding to the most probable symbol being one bit long. Whereas having probability no less than 0.4 is a tight sufficient condition for this to be the case in Huffman coding, other penalties differ, some having a tighter condition, some a looser condition, and others having no such sufficient condition. The objectives explored here are ones for which optimal codes can be found using a generalized form of Huffman coding. These objectives include one related to queueing (an increasing exponential average), one related to single-shot c...
On interpretations of bounded arithmetic and bounded set theory
Pettigrew, Richard
2008-01-01
In a recent paper, Kaye and Wong proved the following result, which they considered to belong to the folklore of mathematical logic. THEOREM: The first-order theories of Peano arithmetic and ZF with the axiom of infinity negated are mutually interpretable with interpretations that are inverse to each other. In this note, I describe a theory of sets that stands in the same relation to the bounded arithmetic IDelta0 + exp. Because of the weakness of this theory of sets, I cannot straightforwardly adapt Kaye and Wong's interpretation of the arithmetic in the set theory. Instead, I am forced to produce a different interpretation.
Upper Bounds on Numerical Approximation Errors
DEFF Research Database (Denmark)
Raahauge, Peter
2004-01-01
This paper suggests a method for determining rigorous upper bounds on approximationerrors of numerical solutions to infinite horizon dynamic programming models.Bounds are provided for approximations of the value function and the policyfunction as well as the derivatives of the value function....... The bounds apply to moregeneral problems than existing bounding methods do. For instance, since strict concavityis not required, linear models and piecewise linear approximations can bedealt with. Despite the generality, the bounds perform well in comparison with existingmethods even when applied...... to approximations of a standard (strictly concave)growth model.KEYWORDS: Numerical approximation errors, Bellman contractions, Error bounds...
Improved complexity bounds for real root isolation using Continued Fractions
Tsigaridas, Elias
2010-01-01
We consider the problem of isolating the real roots of a square-free polynomial with integer coefficients using (variants of) the continued fraction algorithm (CF). We introduce a novel way to compute a lower bound on the positive real roots of univariate polynomials. This allows us to derive a worst case bound of $\\sOB(d^6 + d^4\\tau^2 + d^3\\tau^2)$ for isolating the real roots of a polynomial with integer coefficients using the classic variant of CF, where $d$ is the degree of the polynomial and $\\tau$ the maximum bitsize of its coefficients. This improves the previous bound by Sharma \\cite{sharma-tcs-2008} by a factor of $d^3$ and matches the bound derived by Mehlhorn and Ray \\cite{mr-jsc-2009} for another variant of CF; it also matches the worst case bound of the subdivision-based solvers. We present a new variant of CF, we call it iCF, that isolates the real roots of a polynomial with integer coefficients in $\\sOB(d^5+d^4\\tau)$, thus improving the current known bound for the problem by a factor of $d$. If...
Improved complexity bounds for real root isolation using Continued Fractions
Tsigaridas, Elias
2010-01-01
We consider the problem of isolating the real roots of a square-free polynomial with integer coefficients using (variants of) the continued fraction algorithm (CF). We introduce a novel way to compute a lower bound on the positive real roots of univariate polynomials. This allows us to derive a worst case bound of $\\sOB( d^6 + d^4\\tau^2 + d^3\\tau^2)$ for isolating the real roots of a polynomial with integer coefficients using the classic variant of CF, where $d$ is the degree of the polynomial and $\\tau$ the maximum bitsize of its coefficients. This improves the previous bound by Sharma \\cite{sharma-tcs-2008} by a factor of $d^3$ and matches the bound derived by Mehlhorn and Ray \\cite{mr-jsc-2009} for another variant of CF; it also matches the worst case bound of the subdivision-based solvers. We present a new variant of CF, we call it iCF, that isolates the real roots of a polynomial with integer coefficients in $\\sOB(d^5+d^4\\tau)$, thus improving the current known bound for the problem by a factor of $d$. I...
Thrailkill, Kathryn M; Nyman, Jeffry S; Bunn, R Clay; Uppuganti, Sasidhar; Thompson, Katherine L; Lumpkin, Charles K; Kalaitzoglou, Evangelia; Fowlkes, John L
2017-01-01
Skeletal co-morbidities in type 1 diabetes include an increased risk for fracture and delayed fracture healing, which are intertwined with disease duration and the presence of other diabetic complications. As such, chronic hyperglycemia is undoubtedly a major contributor to these outcomes, despite standard insulin-replacement therapy. Therefore, using the streptozotocin (STZ)-induced model of hypoinsulinemic hyperglycemia in DBA/2J male mice, we compared the effects of two glucose lowering therapies on the fracture resistance of bone and markers of bone turnover. Twelve week-old diabetic (DM) mice were treated for 9weeks with: 1) oral canagliflozin (CANA, dose range ~10-16mg/kg/day), an inhibitor of the renal sodium-dependent glucose co-transporter type 2 (SGLT2); 2) subcutaneous insulin, via minipump (INS, 0.125units/day); 3) co-therapy (CANA+INS); or 4) no treatment (STZ, without therapy). These groups were also compared to non-diabetic control groups. Untreated diabetic mice experienced increased bone resorption and significant deficits in cortical and trabecular bone that contributed to structural weakness of the femur mid-shaft and the lumbar vertebra, as determined by three-point bending and compression tests, respectively. Treatment with either canagliflozin or insulin alone only partially rectified hyperglycemia and the diabetic bone phenotype. However, when used in combination, normalization of glycemic control was achieved, and a prevention of the DM-related deterioration in bone microarchitecture and bone strength occurred, due to additive effects of canagliflozin and insulin. Nevertheless, CANA-treated mice, whether diabetic or non-diabetic, demonstrated an increase in urinary calcium loss; FGF23 was also increased in CANA-treated DM mice. These findings could herald ongoing bone mineral losses following CANA exposure, suggesting that certain CANA-induced skeletal consequences might detract from therapeutic improvements in glycemic control, as they
Bound Polaron Pair Formation in Poly (phenylenevinylenes)
Rothberg, Lewis
The following sections are included: * INTRODUCTION * PHOTOGENERATED YIELD OF SINGLET EXCITONS * AGGREGRATION EFFECTS ON EXCITED STATE PHOTO-GENERATION * ASSIGNMENT TO BOUND POLARON PAIRS AND DISCUSSION * PROBLEMS WITH THE BOUND POLARON PAIR PICTURE AND CONCLUSION * REFERENCES
An Exponential Bound for Cox Regression☆
Kosorok, M. R.
2012-01-01
We present an asymptotic exponential bound for the deviation of the survival function estimator of the Cox model. We show that the bound holds even when the proportional hazards assumption does not hold. PMID:23565013
An Exponential Bound for Cox Regression.
Goldberg, Y; Kosorok, M R
2012-07-01
We present an asymptotic exponential bound for the deviation of the survival function estimator of the Cox model. We show that the bound holds even when the proportional hazards assumption does not hold.
Helioscope bounds on hidden sector photons
Energy Technology Data Exchange (ETDEWEB)
Redondo, J.
2007-12-15
The flux of hypothetical ''hidden photons'' from the Sun is computed under the assumption that they interact with normal matter only through kinetic mixing with the ordinary standard model photon. Requiring that the exotic luminosity is smaller than the standard photon luminosity provides limits for the mixing parameter down to {chi}
Physical bounds for antenna radiation efficiency
Shahpari, Morteza
2016-01-01
Small volume, reduced conductivity and high frequencies are major imperatives in the design of communications infrastructure. The radiation efficiency $\\eta_r$ impacts on the optimal gain, quality factor, and bandwidth. The current efficiency limit applies to structures confined to a radian sphere $ka$ ($k$ is the wave number, $a$ is the radius). Here we present new absolute limits to $\\eta_r$ for arbitrary antenna shapes based on $k^2S$ where $S$ is the conductor surface area. For an electrical length of $10^{-5}$ our result is four orders of magnitude closer to the analytical solution. The improved bound on $\\eta_r$ is more accurate, more general, and easier to calculate than other limits. It is based on the total surface area of the conductors and provides greatly improved estimations for electrically small radiators at very low frequencies. The work is of great benefit to antenna designers assessing new materials such as conductive polymers.
Bounding biomass in the Fisher equation
Birch, Daniel A.; Tsang, Yue-Kin; Young, William R.
2007-06-01
The Fisher-Kolmogorov-Petrovskii-Piskunov equation with a variable growth rate and advection by an incompressible velocity field is considered as a model for plankton dispersed by ocean currents. If the average growth rate is negative then the model has a survival-extinction transition; the location of this transition in the parameter space is constrained using variational arguments and delimited by simulations. The statistical steady state reached when the system is in the survival region of parameter space is characterized by integral constraints and upper and lower bounds on the biomass and productivity that follow from variational arguments and direct inequalities. In the limit of zero-decorrelation time the velocity field is shown to act as Fickian diffusion with an eddy diffusivity much larger than the molecular diffusivity: this allows a one-dimensional model to predict the biomass, productivity, and extinction transitions. All results are illustrated with a simple growth and stirring model.
Helioscope bounds on hidden sector photons
Energy Technology Data Exchange (ETDEWEB)
Redondo, J.
2007-12-15
The flux of hypothetical ''hidden photons'' from the Sun is computed under the assumption that they interact with normal matter only through kinetic mixing with the ordinary standard model photon. Requiring that the exotic luminosity is smaller than the standard photon luminosity provides limits for the mixing parameter down to {chi}
Counting and Enumeration Problems with Bounded Treewidth
Pichler, Reinhard; Rümmele, Stefan; Woltran, Stefan
By Courcelle's Theorem we know that any property of finite structures definable in monadic second-order logic (MSO) becomes tractable over structures with bounded treewidth. This result was extended to counting problems by Arnborg et al. and to enumeration problems by Flum et al. Despite the undisputed importance of these results for proving fixed-parameter tractability, they do not directly yield implementable algorithms. Recently, Gottlob et al. presented a new approach using monadic datalog to close the gap between theoretical tractability and practical computability for MSO-definable decision problems. In the current work we show how counting and enumeration problems can be tackled by an appropriate extension of the datalog approach.
New bounds for multi-dimensional packing
Seiden, S.; Stee, van, Rob
2001-01-01
New upper and lower bounds are presented for a multi-dimensional generalization of bin packing called box packing. Several variants of this problem, including bounded space box packing, square packing, variable sized box packing and resource augmented box packing are also studied. The main results, stated for d=2, are as follows: A new upper bound of 2.66013 for online box packing, a new $14/9 + varepsilon$ polynomial time offline approximation algorithm for square packing, a new upper bound ...
The Acquisition of Bound and Free Anaphora.
Koster, Jan; Koster, Charlotte
Most linguists assume that bound anaphors such as "himself" are connected with their antecedents in a different way from free anaphors such as "him." Bound anaphora resolution is deterministic, based on Principle A of Chomsky's binding theory. Free anaphors, pronominals, cannot be bound in the domain of reflexives (principle…
Bounded rationality and heterogeneous expectations in macroeconomics
D. Massaro
2012-01-01
This thesis studies the effect of individual bounded rationality on aggregate macroeconomic dynamics. Boundedly rational agents are specified as using simple heuristics in their decision making. An important aspect of the type of bounded rationality described in this thesis is that the population of
Bound entangled states invariant under Ux
Institute of Scientific and Technical Information of China (English)
Wang Zhen; Wang Zhi-Xi
2008-01-01
This paper obtains an entangled condition for isotropic-like states by using an atomic map. It constructs a class of bound entangled states from the entangled condition and shows that the partial transposition of the state from the constructed bound entangled class is an edge bound entangled state by using range criterion.
Tight adversary bounds for composite functions
Hoyer, P.; Spalek, R.
2005-01-01
The quantum adversary method is a very versatile method for proving lower bounds on quantum algorithms. It has many equivalent formulations, yields tight bounds for many computational problems, and has natural connections to classical lower bounds. One of its formulations is in terms of the spectral
Determining Normal-Distribution Tolerance Bounds Graphically
Mezzacappa, M. A.
1983-01-01
Graphical method requires calculations and table lookup. Distribution established from only three points: mean upper and lower confidence bounds and lower confidence bound of standard deviation. Method requires only few calculations with simple equations. Graphical procedure establishes best-fit line for measured data and bounds for selected confidence level and any distribution percentile.
Computing the bounds on the loss rates
Fourneau J.-M.; Mokdad L.; Pekergin N.
2002-01-01
We consider an example network where we compute the bounds on cell loss rates. The stochastic bounds for these loss rates using simple arguments lead to models easier to solve. We proved, using stochastic orders, that the loss rates of these easier models are really the bounds of our original model. For ill-balanced configurations these models give good estimates of loss rates.
Labeling schemes for bounded degree graphs
DEFF Research Database (Denmark)
Adjiashvili, David; Rotbart, Noy Galil
2014-01-01
graphs. Our results complement a similar bound recently obtained for bounded depth trees [Fraigniaud and Korman, SODA 2010], and may provide new insights for closing the long standing gap for adjacency in trees [Alstrup and Rauhe, FOCS 2002]. We also provide improved labeling schemes for bounded degree...
Counting Young Tableaux of Bounded Height
Bergeron, Francois; Gascon, Francis
2000-03-01
We show that formulas of Gessel, for the generating functions for Young standard tableaux of height bounded by k (see [2]), satisfy linear differential equations, with polynomial coefficients, equivalent to P-recurrences conjectured by Favreau, Krob and the first author (see [1]) for the number of bounded height tableaux and pairs of bounded height tableaux.
Boosting equal time bound states
Dietrich, Dennis D; Jarvinen, Matti
2012-01-01
We present an explicit and exact boost of a relativistic bound state defined at equal time of the constituents in the Born approximation (lowest order in hbar). To this end, we construct the Poincar\\'e generators of QED and QCD in D=1+1 dimensions, using Gauss' law to express A^0 in terms of the fermion fields in A^1=0 gauge. We determine the fermion-antifermion bound states in the Born approximation as eigenstates of the time and space translation generators P^0 and P^1. The boost operator is combined with a gauge transformation so as to maintain the gauge condition A^1=0 in the new frame. We verify that the boosted state remains an eigenstate of P^0 and P^1 with appropriately transformed eigenvalues and determine the transformation law of the equal-time, relativistic wave function. The shape of the wave function is independent of the CM momentum when expressed in terms of a variable, which is quadratically related to the distance x between the fermions. As a consequence, the Lorentz contraction of the wave ...
Asymmetric dark matter bound state
Bi, Xiao-Jun; Kang, Zhaofeng; Ko, P.; Li, Jinmian; Li, Tianjun
2017-02-01
We propose an interesting framework for asymmetric scalar dark matter (ADM), which has novel collider phenomenology in terms of an unstable ADM bound state (ADMonium) produced via Higgs portals. ADMonium is a natural consequence of the basic features of ADM: the (complex scalar) ADM is charged under a dark local U (1 )d symmetry which is broken at a low scale and provides a light gauge boson X . The dark gauge coupling is strong and then ADM can annihilate away into X -pair effectively. Therefore, the ADM can form a bound state due to its large self-interaction via X mediation. To explore the collider signature of ADMonium, we propose that ADM has a two-Higgs doublet portal. The ADMonium can have a sizable mixing with the heavier Higgs boson, which admits a large cross section of ADMonium production associated with b b ¯. The resulting signature at the LHC depends on the decays of X . In this paper we consider a case of particular interest: p p →b b ¯ +ADMonium followed by ADMonium→2 X →2 e+e- where the electrons are identified as (un)converted photons. It may provide a competitive explanation to heavy di-photon resonance searches at the LHC.
Decoherence in time evolution of bound entanglement
Sun, Z; Sun, C P; Wang, X; Sun, Zhe; Wang, Xiaoguang
2007-01-01
We study a dynamic process of disentanglement by considering the time evolution of bound entanglement for a quantum open system, two qutrits coupling to a common environment. Here, the initial quantum correlations of the two qutrits are characterized by the bound entanglement. In order to show the universality of the role of environment on bound entanglement, both bosonic and spin environments are considered. We found that the bound entanglement displays collapses and revivals, and it can be stable against small temperature and time change. The thermal fluctuation effects on bound entanglement are also considered.
Capacity Bounds for Parallel Optical Wireless Channels
Chaaban, Anas
2016-01-01
A system consisting of parallel optical wireless channels with a total average intensity constraint is studied. Capacity upper and lower bounds for this system are derived. Under perfect channel-state information at the transmitter (CSIT), the bounds have to be optimized with respect to the power allocation over the parallel channels. The optimization of the lower bound is non-convex, however, the KKT conditions can be used to find a list of possible solutions one of which is optimal. The optimal solution can then be found by an exhaustive search algorithm, which is computationally expensive. To overcome this, we propose low-complexity power allocation algorithms which are nearly optimal. The optimized capacity lower bound nearly coincides with the capacity at high SNR. Without CSIT, our capacity bounds lead to upper and lower bounds on the outage probability. The outage probability bounds meet at high SNR. The system with average and peak intensity constraints is also discussed.
Exact entanglement bases and general bound entanglement
Zhong, Z Z
2004-01-01
In this paper, we give the more general bound entangled states associated with the unextendible product bases (UPB), i.e. by using of the exact entanglement bases (EEB) and the complete basis with unextendible product bases (CBUPB), we prove that the arbitrary convex sums of the uniform mixtures (bound entangled states) associated with UPBs are still bound entangled states. Further, we discuss the equivalent transformation group and classification of the CBUPBs, and by using this classification, we prove that in the meaning of indistinguishability, the set of the above all possible bound entangled states can be reduced to the set of all possible mixtures of some fixed basic bound entangled states. At last, we prove that every operating of the partial transposition (PT) map acting upon a density matrix under any bipartite partitioning induces a mapping from the above reduced set of bound entangled states to oneself, which corresponds to a non-identical permutation of the basic bound entangled states.
Thermodynamic law from the entanglement entropy bound
Park, Chanyong
2015-01-01
From black hole thermodynamics, the Bekenstein bound has been proposed as a universal thermal entropy bound. It has been further generalized to an entanglement entropy bound which is valid even in a quantum system. In a quantumly entangled system, the non-negativity of the relative entropy leads to the entanglement entropy bound. When the entanglement entropy bound is saturated, a quantum system satisfies the thermodynamics-like law with an appropriately defined entanglement temperature. We show that the saturation of the entanglement entropy bound accounts for a universal feature of the entanglement temperature proportional to the inverse of the system size. In addition, we also find that a global quench unlike the excitation does not preserve the entanglement entropy bound.
Universal bound on the efficiency of molecular motors
Pietzonka, Patrick; Barato, Andre C.; Seifert, Udo
2016-12-01
The thermodynamic uncertainty relation provides an inequality relating any mean current, the associated dispersion and the entropy production rate for arbitrary non-equilibrium steady states. Applying it here to a general model of a molecular motor running against an external force or torque, we show that the thermodynamic efficiency of such motors is universally bounded by an expression involving only experimentally accessible quantities. For motors pulling cargo through a viscous fluid, a universal bound for the corresponding Stokes efficiency follows as a variant. A similar result holds if mechanical force is used to synthesize molecules of high chemical potential. Crucially, no knowledge of the detailed underlying mechano-chemical mechanism is required for applying these bounds.
Directory of Open Access Journals (Sweden)
Cedric Jurysta
2013-01-01
Full Text Available Background/Aims: The expression and localization of several distinct glucose transporters (GLUT1, GLUT2, GLUT4, and SGLT1 was recently characterized in the parotid gland of normal rats by quantitative real-time PCR analysis, immunohistochemistry and Western blotting. The major aims of the present study was to compare the mRNA expression of these glucose transporters in both the parotid gland and submaxillary gland of control rats, streptozotocin-induced diabetic rats and hereditarily diabetic Goto-Kakizaki rats. Methods: Quantitative real-time PCR analysis was performed in the parotid and submaxillary salivary glands and, for purpose of comparison, also in the heart, kidney, liver, lung, muscle and pancreas from control animals and either streptozotocin-treated or Goto-Kakizaki rats. Results: The expression of GLUT4, but not GLUT1 or SGLT1, mRNA was decreased in the diabetic rats. The results also allow comparing both the mRNA expression level of the four glucose transporters in salivary glands and six other organs, and the diabetes-induced changes in such an expression in distinct locations. Conclusion: The mRNA expression of the insulin-dependent GLUT4 transporter was the sole to be significantly decreased in the salivary glands of diabetic animals. The possible consequence of such a decrease in terms of the control of salivary glucose concentration requires further investigation.
Lo, Margaret C; Lansang, M Cecilia
2013-01-01
Nearly 285 million people worldwide, with 10% being Americans, suffer from diabetes mellitus and its associated comorbidities. This is projected to increase by 6.5% per year, with 439 million inflicted by year 2030. Both morbidity and mortality from diabetes stem from the consequences of microvascular and macrovascular complications. Of the 285 million with diabetes, over a quarter of a million die per year from related complications, making diabetes the fifth leading cause of death in high-income countries. These startling statistics illustrate the therapeutic failure of current diabetes drugs to retard the progression of diabetes. These statistics further illustrate the continual need for further research and development of alternative drugs with novel mechanisms to slow disease progression and disease complications. The treatment algorithm updated in 2008 by American Diabetes Association and the European Association for the Study of Diabetes currently recommends the traditional medications of metformin, either as monotherapy or in combination with sulfonylurea or insulin, as the preferred choice in the tier 1 option. The algorithm only suggests addition of alternative medications such as pioglitazone and incretin-based drugs as second-line agents in the tier 2 "less well-validated" option. However, these traditional medications have not proven to delay the progressive course of diabetes as evidence of increasing need over time for multiple drug therapy to maintain sufficient glycemic control. Because current diabetes medications have limited efficacy and untoward side effects, the development of diabetes mellitus drugs with newer mechanisms of action continues. This article will review the clinical data on the newly available incretin-based drugs on the market, including glucagon-like peptide agonists and of dipeptidyl peptidase type-4 inhibitors. It will also discuss 2 unique medications: pramlintide, which is indicated for both type and type-2 diabetes, and
Hsu, Chia Wei; Zhen, Bo; Stone, A. Douglas; Joannopoulos, John D.; Soljačić, Marin
2016-09-01
Bound states in the continuum (BICs) are waves that remain localized even though they coexist with a continuous spectrum of radiating waves that can carry energy away. Their very existence defies conventional wisdom. Although BICs were first proposed in quantum mechanics, they are a general wave phenomenon and have since been identified in electromagnetic waves, acoustic waves in air, water waves and elastic waves in solids. These states have been studied in a wide range of material systems, such as piezoelectric materials, dielectric photonic crystals, optical waveguides and fibres, quantum dots, graphene and topological insulators. In this Review, we describe recent developments in this field with an emphasis on the physical mechanisms that lead to BICs across seemingly very different materials and types of waves. We also discuss experimental realizations, existing applications and directions for future work.
Towards Bounded Infeasible Code Detection
Christ, Jürgen; Schäf, Martin
2012-01-01
A first step towards more reliable software is to execute each statement and each control-flow path in a method once. In this paper, we present a formal method to automatically compute test cases for this purpose based on the idea of a bounded infeasible code detection. The method first unwinds all loops in a program finitely often and then encodes all feasible executions of the loop-free programs in a logical formula. Helper variables are introduced such that a theorem prover can reconstruct the control-flow path of a feasible execution from a satisfying valuation of this formula. Based on this formula, we present one algorithm that computes a feasible path cover and one algorithm that computes a feasible statement cover. We show that the algorithms are complete for loop-free programs and that they can be implemented efficiently. We further provide a sound algorithm to compute procedure summaries which makes the method scalable to larger programs.
Institute of Scientific and Technical Information of China (English)
张波; 杨文英
2016-01-01
[Summary] As of 2014, an estimated 387 million people have diabetes mellitus ( DM) worldwide, which represents 8.3%of the adult population.China Noncommunicable Disease Surveillance in 2010 shows that the overall prevalence of DM is estimated to be 11.6%(approximately 113.9 million) in the Chinese adult population, with the prevalence among men of 12.1%and women of 11.0%, respectively.Control of blood glucose is fundamental to DM management.Despite the availability of several antihyperglycemic agents, only 53%of patients with DM achieve the recommended goals for DM care of HbA1C<7.0%.According to the National Health and Nutrition Examination Survey and the Behavioral Risk Factor Surveillance System Survey during the period of 10 years in the United States, 33.4%to 48.7%of persons with DM still have not met the targets for glycemic control, blood pressure or lipid level.In order to improve glycemic control, there is a need for new therapeutic options with innovative mechanisms of action and acceptable safety profiles.As a newly developed class of oral antidiabetic drugs, sodium-glucose co-transporter 2 inhibitors(SGLT2i) have recently been approved for the treatment of patients with type 2 diabetes mellitus, including canagliflozin, dapagliflozin, and empagliflozin.Evidence from clinical trials has suggested promising efficacy and safety of SGLT2i when used as monotherapy or in combination with other antihyperglycemic medications.SGLT2i significantly reduce HbA1C and fasting plasma glucose, and are well tolerated in general with a low intrinsic propensity to cause hypoglycemia, as well as rare severe renal or cardiovascular adverse events reported.%2014年全球确诊糖尿病患者共3．87亿例，患病率8．3％。2010年中国慢病监测暨糖尿病专题调查显示，中国成人糖尿病患病率为11．6％（约1．139亿例），男性和女性分别为12．1％和11．0％。血糖控制对2型糖尿病的治疗管理至关重要。
Bounding the space of holographic CFTs with chaos
Energy Technology Data Exchange (ETDEWEB)
Perlmutter, Eric [Department of Physics, Princeton University,Jadwin Hall, Princeton, NJ 08544 (United States)
2016-10-13
Thermal states of quantum systems with many degrees of freedom are subject to a bound on the rate of onset of chaos, including a bound on the Lyapunov exponent, λ{sub L}≤2π/β. We harness this bound to constrain the space of putative holographic CFTs and their would-be dual theories of AdS gravity. First, by studying out-of-time-order four-point functions, we discuss how λ{sub L}=2π/β in ordinary two-dimensional holographic CFTs is related to properties of the OPE at strong coupling. We then rule out the existence of unitary, sparse two-dimensional CFTs with large central charge and a set of higher spin currents of bounded spin; this implies the inconsistency of weakly coupled AdS{sub 3} higher spin gravities without infinite towers of gauge fields, such as the SL(N) theories. This fits naturally with the structure of higher-dimensional gravity, where finite towers of higher spin fields lead to acausality. On the other hand, unitary CFTs with classical W{sub ∞}[λ] symmetry, dual to 3D Vasiliev or hs[λ] higher spin gravities, do not violate the chaos bound, instead exhibiting no chaos: λ{sub L}=0. Independently, we show that such theories violate unitarity for |λ|>2. These results encourage a tensionless string theory interpretation of the 3D Vasiliev theory.
Resignation Syndrome: Catatonia? Culture-Bound?
Sallin, Karl; Lagercrantz, Hugo; Evers, Kathinka; Engström, Ingemar; Hjern, Anders; Petrovic, Predrag
2016-01-01
Resignation syndrome (RS) designates a long-standing disorder predominately affecting psychologically traumatized children and adolescents in the midst of a strenuous and lengthy migration process. Typically a depressive onset is followed by gradual withdrawal progressing via stupor into a state that prompts tube feeding and is characterized by failure to respond even to painful stimuli. The patient is seemingly unconscious. Recovery ensues within months to years and is claimed to be dependent on the restoration of hope to the family. Descriptions of disorders resembling RS can be found in the literature and the condition is unlikely novel. Nevertheless, the magnitude and geographical distribution stand out. Several hundred cases have been reported exclusively in Sweden in the past decade prompting the Swedish National Board of Health and Welfare to recognize RS as a separate diagnostic entity. The currently prevailing stress hypothesis fails to account for the regional distribution and contributes little to treatment. Consequently, a re-evaluation of diagnostics and treatment is required. Psychogenic catatonia is proposed to supply the best fit with the clinical presentation. Treatment response, altered brain metabolism or preserved awareness would support this hypothesis. Epidemiological data suggests culture-bound beliefs and expectations to generate and direct symptom expression and we argue that culture-bound psychogenesis can accommodate the endemic distribution. Last, we review recent models of predictive coding indicating how expectation processes are crucially involved in the placebo and nocebo effect, delusions and conversion disorders. Building on this theoretical framework we propose a neurobiological model of RS in which the impact of overwhelming negative expectations are directly causative of the down-regulation of higher order and lower order behavioral systems in particularly vulnerable individuals. PMID:26858615
Resignation syndrome: Catatonia? Culture-bound?
Directory of Open Access Journals (Sweden)
Karl eSallin
2016-01-01
Full Text Available Resignation syndrome (RS designates a long-standing disorder predominately affecting psychologically traumatised children and adolescents in the midst of a strenuous and lengthy migration process. Typically a depressive onset is followed by gradual withdrawal progressing via stupor into a state that prompts tube feeding and is characterised by failure to respond even to painful stimuli. The patient is seemingly unconscious. Recovery ensues within months to years and is claimed to be dependent on the restoration of hope to the family.Descriptions of disorders resembling RS can be found in the literature and the condition is unlikely novel. Nevertheless, the magnitude and geographical distribution stand out. Several hundred cases have been reported exclusively in Sweden in the past decade prompting the Swedish National Board of Health and Welfare to recognise RS as a separate diagnostic entity. The currently prevailing stress hypothesis fails to account for the regional distribution and contributes little to treatment. Consequently, a re-evaluation of diagnostics and treatment is required. Psychogenic catatonia is proposed to supply the best fit with the clinical presentation. Treatment response, altered brain metabolism or preserved awareness would support this hypothesis.Epidemiological data suggests culture-bound beliefs and expectations to generate and direct symptom expression and we argue that culture-bound psychogenesis can accommodate the endemic distribution.Last, we review recent models of predictive coding indicating how expectation processes are crucially involved in the placebo and nocebo effect, delusions and conversion disorders. Building on this theoretical framework we propose a neurobiological model of RS in which the impact of overwhelming negative expectations are directly causative of the down-regulation of higher order and lower order behavioural systems in particularly vulnerable individuals.
Using tolerance bounds in scientific investigations
Energy Technology Data Exchange (ETDEWEB)
Wendelberger, J.R.
1996-07-01
Assessment of the variability in population values plays an important role in the analysis of scientific data. Analysis of scientific data often involves developing a bound on a proportion of a population. Sometimes simple probability bounds are obtained using formulas involving known mean and variance parameters and replacing the parameters by sample estimates. The resulting bounds are only approximate and fail to account for the variability in the estimated parameters. Tolerance bounds provide bounds on population proportions which account for the variation resulting from the estimated mean and variance parameters. A beta content, gamma confidence tolerance interval is constructed so that a proportion beta of the population lies within the region bounded by the interval with confidence gamma. An application involving corrosion measurements is used to illustrate the use of tolerance bounds for different situations. Extensions of standard tolerance intervals are applied to generate regression tolerance bounds, tolerance bounds for more general models of measurements collected over time, and tolerance intervals for varying precision data. Tolerance bounds also provide useful information for designing the collection of future data.
Bound anionic states of adenine
Energy Technology Data Exchange (ETDEWEB)
Haranczyk, Maciej; Gutowski, Maciej S; Li, Xiang; Bowen, Kit H
2007-03-20
Anionic states of nucleic acid bases are involved in DNA damage by low-energy electrons and in charge transfer through DNA. Previous gas phase studies of free, unsolvated nucleic acid base parent anions probed only dipole-bound states, which are not present in condensed phase environments, but did not observe valence anionic states, which for purine bases, are thought to be adiabatically unbound. Contrary to this expectation, we have demonstrated that some thus far ignored tautomers of adenine, which result from enamine-imine transformations, support valence anionic states with electron vertical detachment energies as large as 2.2 eV, and at least one of these anionic tautomers is adiabatically bound. Moreover, we predict that the new anionic tautomers should also dominate in solutions and should be characterized by larger values of electron vertical detachment energy than the canonical valence anion. All of the new-found anionic tautomers might be formed in the course of dissociative electron attachment followed by a hydrogen atom attachment to a carbon atom, and they might affect the structure and properties of DNA and RNA exposed to low-energy electrons. The discovery of these valence anionic states of adenine was facilitated by the development of: (i) a new experimental method for preparing parent anions of nucleic acid bases for photoelectron experiments, and (ii) a new combinatorial/ quantum chemical approach for identification of the most stable tautomers of organic molecules. The computational portion of this work was supported by the: (i) Polish State Committee for Scientific Research (KBN) Grants: DS/8000-4-0140-7 (M.G.) and N204 127 31/2963 (M.H.), (ii) European Social Funds (EFS) ZPORR/2.22/II/2.6/ARP/U/2/05 (M.H.), and (iii) US DOE Office of Biological and Environmental Research, Low Dose Radiation Research Program (M.G.). M.H. holds the Foundation for Polish Science (FNP) award for young scientists. The calculations were performed at the Academic
Nonadditivity of Rains' bound for distillable entanglement
Wang, Xin; Duan, Runyao
2017-06-01
Rains' bound is arguably the best known upper bound of the distillable entanglement by operations completely preserving positivity of partial transpose (PPT) and was conjectured to be additive and coincide with the asymptotic relative entropy of entanglement. We disprove both conjectures by explicitly constructing a special class of mixed two-qubit states. We then introduce an additive semidefinite programming lower bound (EM) for the asymptotic Rains' bound, and it immediately becomes a computable lower bound for entanglement cost of bipartite states. Furthermore, EM is also proved to be the best known upper bound of the PPT-assisted deterministic distillable entanglement and gives the asymptotic rates for all pure states and some class of genuinely mixed states.
Process expression of bounded Petri nets
Institute of Scientific and Technical Information of China (English)
吴哲辉
1996-01-01
The concept of process expression of bounded Petri nets is presented.Moreover,an algorithm to find the process expression for a bounded Petri net is given.A process expression of a bounded Petri net is a regular expression whose every alphabet symbol represents a basic subprocess of the net.The regular set expressed by the regular expression is the set of all surjective processes of a bounded Petri net.A surjective process of a bounded Petri net is a process of this net in which every s-cut corresponds to a reachable marking of the net.Therefore,all surjective processes of a bounded Petri net can be obtained as long as its process expression and the basic subprocess represented by the alphabet symbols of the process expression are given.
Thermodynamic law from the entanglement entropy bound
Park, Chanyong
2016-04-01
From black hole thermodynamics, the Bekenstein bound has been proposed as a universal thermal entropy bound. It has been further generalized to an entanglement entropy bound which is valid even in a quantum system. In a quantumly entangled system, the non-negativity of the relative entropy leads to the entanglement entropy bound. When the entanglement entropy bound is saturated, a quantum system satisfies the thermodynamicslike law with an appropriately defined entanglement temperature. We show that the saturation of the entanglement entropy bound accounts for a universal feature of the entanglement temperature proportional to the inverse of the system size. In addition, we show that the deformed modular Hamiltonian under a global quench also satisfies the generalized entanglement entropy boundary after introducing a new quantity called the entanglement chemical potential.
Bounds on double-diffusive convection
Balmforth, Neil J.; Ghadge, Shilpa A.; Kettapun, Atichart; Mandre, Shreyas D.
2006-12-01
We consider double-diffusive convection between two parallel plates and compute bounds on the flux of the unstably stratified species using the background method. The bound on the heat flux for Rayleigh Bénard convection also serves as a bound on the double-diffusive problem (with the thermal Rayleigh number equal to that of the unstably stratified component). In order to incorporate a dependence of the bound on the stably stratified component, an additional constraint must be included, like that used by Joseph (Stability of Fluid Motion, 1976, Springer) to improve the energy stability analysis of this system. Our bound extends Joseph's result beyond his energy stability boundary. At large Rayleigh number, the bound is found to behave like R_T(1/2) for fixed ratio R_S/R_T, where R_T and R_S are the Rayleigh numbers of the unstably and stably stratified components, respectively.
Instanton bound states in ABJM theory
Energy Technology Data Exchange (ETDEWEB)
Hatsuda, Yasuyuki [DESY Hamburg (Germany). Theory Group; Tokyo Institute of Technology (Japan). Dept. of Physics; Moriyama, Sanefumi [Nagoya Univ. (Japan). Kobayashi Maskawa Inst. and Graduate School of Mathematics; Okuyama, Kazumi [Shinshu Univ., Matsumoto, Nagano (Japan). Dept. of Physics
2013-06-15
The partition function of the ABJM theory receives non-perturbative corrections due to instanton effects. We study these non-perturbative corrections, including bound states of worldsheet instantons and membrane instantons, in the Fermi-gas approach. We require that the total non-perturbative correction should be always finite for arbitrary Chern-Simons level. This finiteness is realized quite non-trivially because each bound state contribution naively diverges at some levels. The poles of each contribution should be canceled out in total. We use this pole cancellation mechanism to find unknown bound state corrections from known ones. We conjecture a general expression of the bound state contribution. Summing up all the bound state contributions, we find that the effect of bound states is simply incorporated into the worldsheet instanton correction by a redefinition of the chemical potential in the Fermi-gas system. Analytic expressions of the 3- and 4-membrane instanton corrections are also proposed.
Conditionally bounding analytic ranks of elliptic curves
Bober, Jonathan W
2011-01-01
We describe a method for bounding the rank of an elliptic curve under the assumptions of the Birch and Swinnerton-Dyer conjecture and the generalized Riemann hypothesis. As an example, we compute, under these conjectures, exact upper bounds for curves which are known to have rank at least as large as 20, 21, 22, 23, and 24. For the known curve of rank at least 28, we get a bound of 30.
Computing the bounds on the loss rates
Directory of Open Access Journals (Sweden)
Fourneau J.-M.
2002-01-01
Full Text Available We consider an example network where we compute the bounds on cell loss rates. The stochastic bounds for these loss rates using simple arguments lead to models easier to solve. We proved, using stochastic orders, that the loss rates of these easier models are really the bounds of our original model. For ill-balanced configurations these models give good estimates of loss rates.
Scalable Capacity Bounding Models for Wireless Networks
Du, Jinfeng; Medard, Muriel; Xiao, Ming; Skoglund, Mikael
2014-01-01
The framework of network equivalence theory developed by Koetter et al. introduces a notion of channel emulation to construct noiseless networks as upper (resp. lower) bounding models, which can be used to calculate the outer (resp. inner) bounds for the capacity region of the original noisy network. Based on the network equivalence framework, this paper presents scalable upper and lower bounding models for wireless networks with potentially many nodes. A channel decoupling method is proposed...
Risk Bounds for Infinitely Divisible Distribution
Zhang, Chao
2012-01-01
In this paper, we study the risk bounds for samples independently drawn from an infinitely divisible (ID) distribution. In particular, based on a martingale method, we develop two deviation inequalities for a sequence of random variables of an ID distribution with zero Gaussian component. By applying the deviation inequalities, we obtain the risk bounds based on the covering number for the ID distribution. Finally, we analyze the asymptotic convergence of the risk bound derived from one of the two deviation inequalities and show that the convergence rate of the bound is faster than the result for the generic i.i.d. empirical process (Mendelson, 2003).
Some Improved Nonperturbative Bounds for Fermionic Expansions
Energy Technology Data Exchange (ETDEWEB)
Lohmann, Martin, E-mail: marlohmann@gmail.com [Universita di Roma Tre, Dipartimento di Matematica (Italy)
2016-06-15
We reconsider the Gram-Hadamard bound as it is used in constructive quantum field theory and many body physics to prove convergence of Fermionic perturbative expansions. Our approach uses a recursion for the amplitudes of the expansion, discovered in a model problem by Djokic (2013). It explains the standard way to bound the expansion from a new point of view, and for some of the amplitudes provides new bounds, which avoid the use of Fourier transform, and are therefore superior to the standard bounds for models like the cold interacting Fermi gas.
Bounds in the location-allocation problem
DEFF Research Database (Denmark)
Juel, Henrik
1981-01-01
Develops a family of stronger lower bounds on the objective function value of the location-allocation problem. Solution methods proposed to solve problems in location-allocation; Efforts to develop a more efficient bound solution procedure; Determination of the locations of the sources.......Develops a family of stronger lower bounds on the objective function value of the location-allocation problem. Solution methods proposed to solve problems in location-allocation; Efforts to develop a more efficient bound solution procedure; Determination of the locations of the sources....
Conductivity bounds in probe brane models
Ikeda, Tatsuhiko N; Nakai, Yuichiro
2016-01-01
We discuss upper and lower bounds on the electrical conductivity of finite temperature strongly coupled quantum field theories, holographically dual to probe brane models, within linear response. In a probe limit where disorder is introduced entirely through an inhomogeneous background charge density, we find simple lower and upper bounds on the electrical conductivity in arbitrary dimensions. In field theories in two spatial dimensions, we show that both bounds persist even when disorder is included in the bulk metric. We discuss the challenges with finding sharp lower bounds on conductivity in three or more spatial dimensions when the metric is inhomogeneous.
A violation of the covariant entropy bound?
Masoumi, Ali
2014-01-01
Several arguments suggest that the entropy density at high energy density $\\rho$ should be given by the expression $s=K\\sqrt{\\rho/G}$, where $K$ is a constant of order unity. On the other hand the covariant entropy bound requires that the entropy on a light sheet be bounded by $A/4G$, where $A$ is the area of the boundary of the sheet. We find that in a suitably chosen cosmological geometry, the above expression for $s$ violates the covariant entropy bound. We consider different possible explanations for this fact; in particular the possibility that entropy bounds should be defined in terms of volumes of regions rather than areas of surfaces.
A Stronger LP Bound for Formula Size Lower Bounds via Clique Constraints
Ueno, Kenya
2009-01-01
We introduce a new technique proving formula size lower bounds based on the linear programming bound originally introduced by Karchmer, Kushilevitz and Nisan [11] and the theory of stable set polytope. We apply it to majority functions and prove their formula size lower bounds improved from the classical result of Khrapchenko [13]. Moreover, we introduce a notion of unbalanced recursive ternary majority functions motivated by a decomposition theory of monotone self-dual functions and give integrally matching upper and lower bounds of their formula size. We also show monotone formula size lower bounds of balanced recursive ternary majority functions improved from the quantum adversary bound of Laplante, Lee and Szegedy [15].
An outer bound for 2-receiver discrete memoryless broadcast channels
Nair, Chandra
2008-01-01
An outer bound to the two-receiver discrete memoryless broadcast channel is presented. We compare it to the known outer bounds and show that the outer bound presented is at least as tight as the existing bounds.
Helical bound states in the continuum of the edge states in two dimensional topological insulators
Energy Technology Data Exchange (ETDEWEB)
Sablikov, Vladimir A., E-mail: sablikov@gmail.com; Sukhanov, Aleksei A.
2015-09-04
We study bound states embedded into the continuum of edge states in two-dimensional topological insulators. These states emerge in the presence of a short-range potential of a structural defect coupled to the boundary. In this case the edge states flow around the defect and have two resonances in the local density of states. The bound state in continuum (BIC) arises due to an interference of the resonances when they are close to the degeneracy. We find the condition under which the BIC appears, study the spacial distribution of the electron density, and show that the BIC has a helical structure with an electron current circulating around the defect. - Highlights: • We find bound states in the continuum of edge states in 2D topological insulators. • The bound states are induced by an impurity potential and topological order. • The bound state in the continuum has a helical structure of spin and current density.
Tools for model-independent bounds in direct dark matter searches
DEFF Research Database (Denmark)
Cirelli, M.; Del Nobile, E.; Panci, P.
2013-01-01
We discuss a framework (based on non-relativistic operators) and a self-contained set of numerical tools to derive the bounds from some current direct detection experiments on virtually any arbitrary model of Dark Matter elastically scattering on nuclei.......We discuss a framework (based on non-relativistic operators) and a self-contained set of numerical tools to derive the bounds from some current direct detection experiments on virtually any arbitrary model of Dark Matter elastically scattering on nuclei....
No-arbitrage bounds for financial scenarios
DEFF Research Database (Denmark)
Geyer, Alois; Hanke, Michael; Weissensteiner, Alex
2014-01-01
We derive no-arbitrage bounds for expected excess returns to generate scenarios used in financial applications. The bounds allow to distinguish three regions: one where arbitrage opportunities will never exist, a second where arbitrage may be present, and a third, where arbitrage opportunities...
Optimal online bounded space multidimensional packing
L. Epstein (Lea); R. van Stee (Rob)
2003-01-01
textabstractWe solve an open problem in the literature by providing an online algorithm for multidimensional bin packing that uses only bounded space. We show that it is optimal among bounded space algorithms for any dimension $d>1$. Its asymptotic performance ratio is $(Pi_{infty})^d$, where
New bounds for multi-dimensional packing
S. Seiden; R. van Stee (Rob)
2001-01-01
textabstractNew upper and lower bounds are presented for a multi-dimensional generalization of bin packing called box packing. Several variants of this problem, including bounded space box packing, square packing, variable sized box packing and resource augmented box packing are also studied. The
Lower Bounds of Concurrence for Multipartite States
Zhu, Xue-Na; Fei, Shao-Ming
2012-01-01
We study the entanglement of multipartite quantum states. Some lower bounds of the multipartite concurrence are reviewed. We further present more effective lower bounds for detecting and qualifying entanglement, by establishing functional relations between the concurrence and the generalized partial transpositions of the multipartite systems.
A Note on Geodesically Bounded -Trees
Directory of Open Access Journals (Sweden)
Kirk WA
2010-01-01
Full Text Available It is proved that a complete geodesically bounded -tree is the closed convex hull of the set of its extreme points. It is also noted that if is a closed convex geodesically bounded subset of a complete -tree and if a nonexpansive mapping satisfies then has a fixed point. The latter result fails if is only continuous.
New bounds for multi-dimensional packing
Seiden, S.; Stee, R. van
2001-01-01
New upper and lower bounds are presented for a multi-dimensional generalization of bin packing called box packing. Several variants of this problem, including bounded space box packing, square packing, variable sized box packing and resource augmented box packing are also studied. The main results,
Threshold Circuit Lower Bounds on Cryptographic Functions
Kiltz, E.; Simon, H.U.
2005-01-01
In this work, we are interested in non-trivial upper bounds on the spectral norm of binary matrices $M$ from {-1, 1} $^{N × N}$. It is known that the distributed Boolean function represented by $M$ is hard to compute in various restricted models of computation if the spectral norm is bounded from ab
Experimental evidence of bounds of quantum correlations
Bovino, F A; Castelletto, S; Degiovanni, I P; Rastello, M L; Berchera, I R
2003-01-01
We implemented the experiment proposed by Cabello [arXiv:quant-ph/0309172] to test the bounds of quantum correlation. As expected from the theory we found that, for certain choices of local observables, Cirel'son's bound of the Clauser-Horne-Shimony-Holt inequality ($2\\sqrt{2}$) is not reached by any quantum states.
Spatial coagulation with bounded coagulation rate
Bailleul, Ismael
2010-01-01
We prove that the spatial coagulation equation with bounded coagulation rate is well-posed for all times in a given class of kernels if the convection term of the underlying particle dynamics has divergence bounded below by a positive constant. Multiple coagulations, fragmentation and scattering are also considered.
Generalized upper bound for inelastic diffraction
Troshin, S. M.; Tyurin, N. E.
2017-01-01
For inelastic diffraction, we obtain an upper bound valid for the whole range of the elastic scattering amplitude variation allowed by unitarity. We discuss the energy dependence of the inelastic diffractive cross-section on the base of this bound and recent Large Hadron Collider (LHC) data.
A generalized upper bound for inelastic diffraction
Troshin, S M
2016-01-01
For the inelastic diffraction, we obtain an upper bound valid in the whole range of the elastic scattering amplitude variation allowed by unitarity. We discuss the energy dependence of the inelastic diffractive cross-section on the base of this bound and recent LHC data.
On the range of completely bounded maps
Directory of Open Access Journals (Sweden)
Richard I. Loebl
1978-01-01
Full Text Available It is shown that if every bounded linear map from a C*-algebra α to a von Neumann algebra β is completely bounded, then either α is finite-dimensional or β⫅⊗Mn, where is a commutative von Neumann algebra and Mn is the algebra of n×n complex matrices.
Bounds in the location-allocation problem
DEFF Research Database (Denmark)
Juel, Henrik
1981-01-01
Develops a family of stronger lower bounds on the objective function value of the location-allocation problem. Solution methods proposed to solve problems in location-allocation; Efforts to develop a more efficient bound solution procedure; Determination of the locations of the sources....
Nanopore sensing of individual transcription factors bound to DNA
Squires, Allison; Atas, Evrim; Meller, Amit
2015-06-01
Transcription factor (TF)-DNA interactions are the primary control point in regulation of gene expression. Characterization of these interactions is essential for understanding genetic regulation of biological systems and developing novel therapies to treat cellular malfunctions. Solid-state nanopores are a highly versatile class of single-molecule sensors that can provide rich information about local properties of long charged biopolymers using the current blockage patterns generated during analyte translocation, and provide a novel platform for characterization of TF-DNA interactions. The DNA-binding domain of the TF Early Growth Response Protein 1 (EGR1), a prototypical zinc finger protein known as zif268, is used as a model system for this study. zif268 adopts two distinct bound conformations corresponding to specific and nonspecific binding, according to the local DNA sequence. Here we implement a solid-state nanopore platform for direct, label- and tether-free single-molecule detection of zif268 bound to DNA. We demonstrate detection of single zif268 TFs bound to DNA according to current blockage sublevels and duration of translocation through the nanopore. We further show that the nanopore can detect and discriminate both specific and nonspecific binding conformations of zif268 on DNA via the distinct current blockage patterns corresponding to each of these two known binding modes.
Black hole bombs and photon mass bounds
Pani, Paolo; Gualtieri, Leonardo; Berti, Emanuele; Ishibashi, Akihiro
2012-01-01
Generic extensions of the standard model predict the existence of ultralight bosonic degrees of freedom. Several ongoing experiments are aimed at detecting these particles or constraining their mass range. Here we show that massive vector fields around rotating black holes can give rise to a strong superradiant instability which extracts angular momentum from the hole. The observation of supermassive spinning black holes imposes limits on this mechanism. We show that current supermassive black hole spin estimates provide the tightest upper limits on the mass of the photon (mv<4x10^{-20} eV according to our most conservative estimate), and that spin measurements for the largest known supermassive black holes could further lower this bound to mv<10^{-22} eV. Our analysis relies on a novel framework to study perturbations of rotating Kerr black holes in the slow-rotation regime, that we developed up to second order in rotation, and that can be extended to other spacetime metrics and other theories.
Automatic analysis of distance bounding protocols
Malladi, Sreekanth; Kothapalli, Kishore
2010-01-01
Distance bounding protocols are used by nodes in wireless networks to calculate upper bounds on their distances to other nodes. However, dishonest nodes in the network can turn the calculations both illegitimate and inaccurate when they participate in protocol executions. It is important to analyze protocols for the possibility of such violations. Past efforts to analyze distance bounding protocols have only been manual. However, automated approaches are important since they are quite likely to find flaws that manual approaches cannot, as witnessed in literature for analysis pertaining to key establishment protocols. In this paper, we use the constraint solver tool to automatically analyze distance bounding protocols. We first formulate a new trace property called Secure Distance Bounding (SDB) that protocol executions must satisfy. We then classify the scenarios in which these protocols can operate considering the (dis)honesty of nodes and location of the attacker in the network. Finally, we extend the const...
Structural Bounds on the Dyadic Effect
Cinelli, Matteo; Iovanella, Antonio
2016-01-01
In this paper we consider the dyadic effect introduced in complex networks when nodes are distinguished by a binary characteristic. Under these circumstances two independent parameters, namely dyadicity and heterophilicity, are able to measure how much the assigned characteristic affects the network topology. All possible configurations can be represented in a phase diagram lying in a two-dimensional space that represents the feasible region of the dyadic effect, which is bound by two upper bounds on dyadicity and heterophilicity. Using some network's structural arguments, we are able to improve such upper bounds and introduce two new lower bounds, providing a reduction of the feasible region of the dyadic effect as well as constraining dyadicity and heterophilicity within a specific range. Some computational experiences show the bounds' effectiveness and their usefulness with regards to different classes of networks.
Calculation of size for bound-state constituents
Glazek, Stanislaw D
2014-01-01
Elements are given of a calculation that identifies the size of a proton in the Schroedinger equation for lepton-proton bound states, using the renormalization group procedure for effective particles (RGPEP) in quantum field theory, executed only up to the second order of expansion in powers of the coupling constant. Already in this crude approximation, the extraction of size of a proton from bound-state observables is found to depend on the lepton mass, so that the smaller the lepton mass the larger the proton size extracted from the same observable bound-state energy splitting. In comparison of Hydrogen and muon-proton bound-state dynamics, the crude calculation suggests that the difference between extracted proton sizes in these two cases can be a few percent. Such values would match the order of magnitude of currently discussed proton-size differences in leptonic atoms. Calculations using the RGPEP of higher order than second are required for a precise interpretation of the energy splittings in terms of t...
Bounding the Space of Holographic CFTs with Chaos
Perlmutter, Eric
2016-01-01
Thermal states of quantum systems with many degrees of freedom are subject to a bound on the rate of onset of chaos, including a bound on the Lyapunov exponent, $\\lambda_L\\leq 2\\pi /\\beta$. We harness this bound to constrain the space of putative holographic CFTs and their would-be dual theories of AdS gravity. First, by studying out-of-time-order four-point functions, we show how $\\lambda_L=2\\pi/\\beta$ in ordinary holographic CFTs follows from properties of the OPE at strong coupling. We then rule out the existence of unitary, sparse two-dimensional CFTs with large central charge and a set of higher spin currents of bounded spin; this implies the inconsistency of weakly coupled AdS$_3$ higher spin gravities without infinite towers of gauge fields, such as the $SL(N)$ theories. This fits naturally with the structure of higher-dimensional gravity, where finite towers of higher spin fields lead to acausality. On the other hand, unitary CFTs with classical $W_{\\infty}[\\lambda]$ symmetry, dual to 3D Vasiliev or h...
Key management and encryption under the bounded storage model.
Energy Technology Data Exchange (ETDEWEB)
Draelos, Timothy John; Neumann, William Douglas; Lanzone, Andrew J.; Anderson, William Erik
2005-11-01
There are several engineering obstacles that need to be solved before key management and encryption under the bounded storage model can be realized. One of the critical obstacles hindering its adoption is the construction of a scheme that achieves reliable communication in the event that timing synchronization errors occur. One of the main accomplishments of this project was the development of a new scheme that solves this problem. We show in general that there exist message encoding techniques under the bounded storage model that provide an arbitrarily small probability of transmission error. We compute the maximum capacity of this channel using the unsynchronized key-expansion as side-channel information at the decoder and provide tight lower bounds for a particular class of key-expansion functions that are pseudo-invariant to timing errors. Using our results in combination with Dziembowski et al. [11] encryption scheme we can construct a scheme that solves the timing synchronization error problem. In addition to this work we conducted a detailed case study of current and future storage technologies. We analyzed the cost, capacity, and storage data rate of various technologies, so that precise security parameters can be developed for bounded storage encryption schemes. This will provide an invaluable tool for developing these schemes in practice.
Bound-free Spectra for Diatomic Molecules
Schwenke, David W.
2012-01-01
It is now recognized that prediction of radiative heating of entering space craft requires explicit treatment of the radiation field from the infrared (IR) to the vacuum ultra violet (VUV). While at low temperatures and longer wavelengths, molecular radiation is well described by bound-bound transitions, in the short wavelength, high temperature regime, bound-free transitions can play an important role. In this work we describe first principles calculations we have carried out for bound-bound and bound-free transitions in N2, O2, C2, CO, CN, NO, and N2+. Compared to bound ]bound transitions, bound-free transitions have several particularities that make them different to deal with. These include more complicated line shapes and a dependence of emission intensity on both bound state diatomic and atomic concentrations. These will be discussed in detail below. The general procedure we used was the same for all species. The first step is to generate potential energy curves, transition moments, and coupling matrix elements by carrying out ab initio electronic structure calculations. These calculations are expensive, and thus approximations need to be made in order to make the calculations tractable. The only practical method we have to carry out these calculations is the internally contracted multi-reference configuration interaction (icMRCI) method as implemented in the program suite Molpro. This is a widely used method for these kinds of calculations, and is capable of generating very accurate results. With this method, we must first of choose which electrons to correlate, the one-electron basis to use, and then how to generate the molecular orbitals.
Lower Bounds on Q for Finite Size Antennas of Arbitrary Shape
Kim, Oleksiy S
2015-01-01
The problem of the lower bound on the radiation Q for an arbitrarily shaped finite size antenna of non-zero volume is formulated in terms of equivalent electric and magnetic currents densities distributed on a closed surface coinciding with antenna exterior surface. When these equivalent currents radiate in free space, the magnetic current augments the electric current, so that the fields interior to the surface vanish. In contrast to approaches based solely on electric currents, the proposed technique ensures no stored energy interior to the antenna exterior surface, and thus, allows the fundamental lower bound on Q to be determined. To facilitate the computation of the bound, new expressions for the stored energy, radiated power, and Q of coupled electric and magnetic source currents in free space are derived.
On an Outer bound and an Inner Bound for the General Broadcast Channel
Gohari, Amin Aminzadeh; Anantharam, Venkat
2010-01-01
In this paper, we study the Nair-El Gamal outer bound and Marton's inner bound for general two-receiver broadcast channels. We show that the Nair-El Gamal outer bound can be made fully computable. For the inner bound, we show that, unlike in the Gaussian case, for a degraded broadcast channel even without a common message, Marton's coding scheme without a superposition variable is in general insufficient for obtaining the capacity region. Further, we prove various results that help to restrict the search space for computing the sum-rate for Marton's inner bound. We establish the capacity region along certain directions and show that it coincides with Marton's inner bound. Lastly, we discuss an idea that may lead to a larger inner bound.
Positivity bounds on double parton distributions
Energy Technology Data Exchange (ETDEWEB)
Diehl, Markus; Kasemets, Tomas
2013-03-15
Double hard scattering in proton-proton collisions is described in terms of double parton distributions. We derive bounds on these distributions that follow from their interpretation as probability densities, taking into account all possible spin correlations between two partons in an unpolarized proton. These bounds constrain the size of the polarized distributions and can for instance be used to set upper limits on the effects of spin correlations in double hard scattering. We show that the bounds are stable under leading-order DGLAP evolution to higher scales.
Bounds for convection between rough boundaries
Goluskin, David
2016-01-01
We consider Rayleigh-B\\'enard convection in a layer of fluid between no-slip rough boundaries, where the top and bottom boundary heights are functions of the horizontal coordinates with bounded gradients. We use the background method to derive an upper bound on mean heat flux across the layer for all admissible boundary geometries. This flux, normalized by the temperature difference between the boundaries, can grow with the Rayleigh number ($Ra$) no faster than $Ra^{1/2}$ as $Ra \\rightarrow \\infty$. Coefficients of the bound are given explicitly in terms of the geometry, and evaluation of the coefficients is illustrated for sinusoidal boundaries.
On the reflection of magnon bound states
MacKay, Niall
2010-01-01
We investigate the reflection of two-particle bound states of a free open string in the light-cone AdS_5 x S^5 string sigma model, for large angular momentum J=J_56 and ending on a D7 brane which wraps the entire AdS_5 and a maximal S^3 of S^5. We use the superspace formalism to analyse fundamental and two-particle bound states in the cases of supersymmetry-preserving and broken-supersymmetry boundaries. We find the boundary S-matrices corresponding to bound states both in the bulk and on the boundary.
Bounds on List Decoding Gabidulin Codes
Wachter-Zeh, Antonia
2012-01-01
An open question about Gabidulin codes is whether polynomial-time list decoding beyond half the minimum distance is possible or not. In this contribution, we give a lower and an upper bound on the list size, i.e., the number of codewords in a ball around the received word. The lower bound shows that if the radius of this ball is greater than the Johnson radius, this list size can be exponential and hence, no polynomial-time list decoding is possible. The upper bound on the list size uses subspace properties.
Lightweight Distance Bounding Protocol against Relay Attacks
Kim, Jin Seok; Cho, Kookrae; Yum, Dae Hyun; Hong, Sung Je; Lee, Pil Joong
Traditional authentication protocols are based on cryptographic techniques to achieve identity verification. Distance bounding protocols are an enhanced type of authentication protocol built upon both signal traversal time measurement and cryptographic techniques to accomplish distance verification as well as identity verification. A distance bounding protocol is usually designed to defend against the relay attack and the distance fraud attack. As there are applications to which the distance fraud attack is not a serious threat, we propose a streamlined distance bounding protocol that focuses on the relay attack. The proposed protocol is more efficient than previous protocols and has a low false acceptance rate under the relay attack.
Probing Andreev bound states in one-atom superconducting contacts
Energy Technology Data Exchange (ETDEWEB)
Pothier, Hugues; Janvier, Camille; Tosi, Leandro; Girit, Caglar; Goffman, Marcelo; Esteve, Daniel; Urbina, Cristian [Quantronics Group, SPEC, CEA-Saclay (France)
2015-07-01
Superconductors are characterized by a dissipationless current. Since the work of Josephson 50 years ago, it is known that a supercurrent can even flow through tunnel junctions between superconductors. This Josephson effect also occurs through any type of ''weak links'' between superconductors: non-superconducting materials, constrictions,.. A unified understanding of the Josephson effect has emerged from a mesoscopic description of weak links. It relies on the existence of doublets of localized states that have energies below the superconducting gap: the Andreev bound states. I will present experiments performed on the simplest conductor possible, a single-atom contact between superconductors, that illustrate these concepts. The most recent work demonstrates time-domain manipulation of quantum superpositions of Andreev bound states.
Collider Bounds on Lee-Wick Higgs Bosons
Alvarez, Ezequiel; Zurita, José
2011-01-01
We study the constraints on the Lee-Wick Higgs sector arising from direct collider searches. We work in an effective-field theory framework, where all of the Lee-Wick partners are integrated out, with the sole exception of the Lee-Wick Higgs bosons. The resulting theory is a two-Higgs doublet model where the second doublet has wrong-sign kinetic and mass terms. We include the bounds coming from direct Higgs searches at both LEP and Tevatron using the code HiggsBounds, and show the currently excluded parameter space. We also analyze the prospects of LHC Run-I, finding that with a total integrated luminosity of 5 fb $^{-1}$ and a center-of-mass energy of 7 TeV, most of the parameter space for the SM-like CP-even Higgs will be probed.
How entangled are bound entangled states?
Wei, T C; Goldbart, P M; Munro, W J; Wei, Tzu-Chieh; Altepeter, Joseph B.; Goldbart, Paul M.; Munro, William J.
2003-01-01
Bound entangled states are states that are entangled but from which no entanglement can be distilled if all parties are allowed only local operations and classical communication. However, in creating these states one needs nonzero entanglement to start with. To date, no analytic results reveal the entanglement content of these strange states. Here, the entanglement of two distinct multipartite bound entangled states is determined analytically in terms of geometric measure of entanglement and a related quantity. The results are compared with those for the relative entropy of entanglement and the negativity, and plausible lower bounds on the entanglement of formation are given. Along the way, an intriguing example emerges, in which a bipartite mixed state, associated with Smolin's bound entangled state, can be reversibly converted into a bipartite Bell state, and vice versa. Furthermore, for any N-qubit state that is PPT for all bipartite partitionings, there is no violation of the two-setting, three-setting, a...
THE EIGENVALUE PERTURBATION BOUND FOR ARBITRARY MATRICES
Institute of Scientific and Technical Information of China (English)
Wen Li; Jian-xin Chen
2006-01-01
In this paper we present some new absolute and relative perturbation bounds for the eigenvalue for arbitrary matrices, which improves some recent results. The eigenvalue inclusion region is also discussed.
Compositional encoding for bounded model checking
Institute of Scientific and Technical Information of China (English)
Jun SUN; Yang LIU; Jin Song DONG; Jing SUN
2008-01-01
Verification techniques like SAT-based bounded model checking have been successfully applied to a variety of system models. Applying bounded model checking to compositional process algebras is, however, a highly non-trivial task. One challenge is that the number of system states for process algebra models is not statically known, whereas exploring the full state space is computa-tionally expensive. This paper presents a compositional encoding of hierarchical processes as SAT problems and then applies state-of-the-art SAT solvers for bounded model checking. The encoding avoids exploring the full state space for complex systems so as to deal with state space explosion. We developed an automated analyzer which combines complementing model checking tech-niques (I.e., bounded model checking and explicit on-the-fly model checking) to validate system models against event-based temporal properties. The experiment results show the analyzer handles large systems.
Constructive spherical codes near the Shannon bound
Solé, Patrick
2011-01-01
Shannon gave a lower bound in 1959 on the binary rate of spherical codes of given minimum Euclidean distance $\\rho$. Using nonconstructive codes over a finite alphabet, we give a lower bound that is weaker but very close for small values of $\\rho$: The construction is based on the Yaglom map combined with some finite sphere packings obtained from nonconstructive codes for the Euclidean metric. Concatenating geometric codes meeting the TVZ bound with a Lee metric BCH code over GF(p); we obtain spherical codes that are polynomial time constructible. Their parameters outperform those obtained by Lachaud and Stern in 1994. At very high rate they are above 98 per cent of the Shannon bound.
An Exact Black Hole Entropy Bound
Birmingham, Daniel; Birmingham, Danny; Sen, Siddhartha
2001-01-01
We show that a Rademacher expansion can be used to establish an exact bound for the entropy of black holes within a conformal field theory framework. This convergent expansion includes all subleading corrections to the Bekenstein-Hawking term.
Family of nonlocal bound entangled states
Yu, Sixia; Oh, C. H.
2017-03-01
Bound entanglement, being entangled yet not distillable, is essential to our understanding of the relations between nonlocality and entanglement besides its applications in certain quantum information tasks. Recently, bound entangled states that violate a Bell inequality have been constructed for a two-qutrit system, disproving a conjecture by Peres that bound entanglement is local. Here we construct this kind of nonlocal bound entangled state for all finite dimensions larger than two, making possible their experimental demonstration in most general systems. We propose a Bell inequality, based on a Hardy-type argument for nonlocality, and a steering inequality to identify their nonlocality. We also provide a family of entanglement witnesses to detect their entanglement beyond the Bell inequality and the steering inequality.
Vulnerable Derivatives and Good Deal Bounds
DEFF Research Database (Denmark)
Murgoci, Agatha
2013-01-01
can be obtained. We provide a link between the objective probability measure and the range of potential risk-neutral measures, which has an intuitive economic meaning. We also provide tight pricing bounds for European calls and show how to extend the call formula to pricing other financial products......We price vulnerable derivatives – i.e. derivatives where the counterparty may default. These are basically the derivatives traded on the over-the-counter (OTC) markets. Default is modelled in a structural framework. The technique employed for pricing is good deal bounds (GDBs). The method imposes...... a new restriction in the arbitrage free model by setting upper bounds on the Sharpe ratios (SRs) of the assets. The potential prices that are eliminated represent unreasonably good deals. The constraint on the SR translates into a constraint on the stochastic discount factor. Thus, tight pricing bounds...
Bound phenolics in foods, a review.
Acosta-Estrada, Beatriz A; Gutiérrez-Uribe, Janet A; Serna-Saldívar, Sergio O
2014-01-01
Among phytochemicals, phenolic compounds have been extensively researched due to their diverse health benefits. Phenolic compounds occur mostly as soluble conjugates and insoluble forms, covalently bound to sugar moieties or cell wall structural components. Absorption mechanisms for bound phenolic compounds in the gastrointestinal tract greatly depend on the liberation of sugar moieties. Food processes such as fermentation, malting, thermoplastic extrusion or enzymatic, alkaline and acid hydrolyses occasionally assisted with microwave or ultrasound have potential to release phenolics associated to cell walls. Different kinds of wet chemistry methodologies to release and detect bound phenolic have been developed. These include harsh heat treatments, chemical modifications or biocatalysis. New protocols for processing and determining phenolics in food matrices must be devised in order to release bound phenolics and for quality control in the growing functional food industry.
New Spectral Features from Bound Dark Matter
Catena, Riccardo
2016-01-01
We demonstrate that dark matter particles gravitationally bound to the Earth can induce a characteristic nuclear recoil signal at low energies in direct detection experiments. The new spectral feature we predict can provide the ultimate smoking gun for dark matter discovery for experiments with positive signal but unclear background. The new feature is universal, in that the ratio of bound over halo dark matter event rates at detectors is independent of the dark matter-nucleon cross section.
Upper Bounds for the Laplacian Graph Eigenvalues
Institute of Scientific and Technical Information of China (English)
Jiong Sheng LI; Yong Liang PAN
2004-01-01
We first apply non-negative matrix theory to the matrix K = D + A, where D and A are the degree-diagonal and adjacency matrices of a graph G, respectively, to establish a relation on the largest Laplacian eigenvalue λ1 (G) of G and the spectral radius ρ(K) of K. And then by using this relation we present two upper bounds for λ1 (G) and determine the extremal graphs which achieve the upper bounds.
New Spectral Features from Bound Dark Matter
DEFF Research Database (Denmark)
Catena, Riccardo; Kouvaris, Chris
2016-01-01
We demonstrate that dark matter particles gravitationally bound to the Earth can induce a characteristic nuclear recoil signal at low energies in direct detection experiments. The new spectral feature we predict can provide the ultimate smoking gun for dark matter discovery for experiments...... with positive signal but unclear background. The new feature is universal, in that the ratio of bound over halo dark matter event rates at detectors is independent of the dark matter-nucleon cross section....
New Spectral Features from Bound Dark Matter
DEFF Research Database (Denmark)
Catena, Riccardo; Kouvaris, Chris
2016-01-01
We demonstrate that dark matter particles gravitationally bound to the Earth can induce a characteristic nuclear recoil signal at low energies in direct detection experiments. The new spectral feature we predict can provide the ultimate smoking gun for dark matter discovery for experiments...... with positive signal but unclear background. The new feature is universal, in that the ratio of bound over halo dark matter event rates at detectors is independent of the dark matter-nucleon cross section....
The neural basis of bounded rational behavior
Coricelli, Giorgio; Nagel, Rosemarie
2010-01-01
Bounded rational behaviour is commonly observed in experimental games and in real life situations. Neuroeconomics can help to understand the mental processing underlying bounded rationality and out-of-equilibrium behaviour. Here we report results from recent studies on the neural basis of limited steps of reasoning in a competitive setting —the beauty contest game. We use functional magnetic resonance imaging (fMRI) to study the neural correlates of human mental processes in strategic games. ...
New spectral features from bound dark matter
Catena, Riccardo; Kouvaris, Chris
2016-07-01
We demonstrate that dark matter particles gravitationally bound to the Earth can induce a characteristic nuclear recoil signal at low energies in direct detection experiments. The new spectral feature that we predict can provide a complementary verification of dark matter discovery at experiments with positive signal but unclear background. The effect is generically expected, in that the ratio of bound over halo dark matter event rates at detectors is independent of the dark matter-nucleon cross section.
Generalization error bounds for stationary autoregressive models
McDonald, Daniel J; Schervish, Mark
2011-01-01
We derive generalization error bounds for stationary univariate autoregressive (AR) models. We show that the stationarity assumption alone lets us treat the estimation of AR models as a regularized kernel regression without the need to further regularize the model arbitrarily. We thereby bound the Rademacher complexity of AR models and apply existing Rademacher complexity results to characterize the predictive risk of AR models. We demonstrate our methods by predicting interest rate movements.
Lower Bound of Electrical Conductivity from Holography
Ge, Xian-Hui; Wu, Shao-Feng
2015-01-01
We propose a universal lower bound of dc electrical conductivity in rotational- and translational- symmetries breaking systems via the holographic duality. This bound predicts that BTZ-black brane can be easily used to realize linear temperature resistivity. We also construct an anisotropic black brane solution, which yields linear temperature for the in-plane resistivity and insulating behavior for the out-of-plane resistivity. Ultimately, we discuss its implications in experiments.
Eigenvalue variance bounds for covariance matrices
Dallaporta, Sandrine
2013-01-01
This work is concerned with finite range bounds on the variance of individual eigenvalues of random covariance matrices, both in the bulk and at the edge of the spectrum. In a preceding paper, the author established analogous results for Wigner matrices and stated the results for covariance matrices. They are proved in the present paper. Relying on the LUE example, which needs to be investigated first, the main bounds are extended to complex covariance matrices by means of the Tao, Vu and Wan...
Effective Height Upper Bounds on Algebraic Tori
Habegger, Philipp
2012-01-01
The main emphasis will be on height upper bounds in the algebraic torus G^{n}_{m}. By height we will mean the absolute logarithmic Weil height. Section 3.2 contains a precise definition of this and other more general height functions. The first appendix gives a short overview of known results in the abelian case. The second appendix contains a few height bounds in Shimura varieties.
Structure Biology of Membrane Bound Enzymes
Energy Technology Data Exchange (ETDEWEB)
Fu, Dax [Johns Hopkins Univ., Baltimore, MD (United States). School of Medicine. Dept. of Physiology
2016-11-30
The overall goal of the proposed research is to understand the membrane-associated active processes catalyzed by an alkane $\\square$-hydroxylase (AlkB) from eubacterium Pseudomonase oleovorans. AlkB performs oxygenation of unactivated hydrocarbons found in crude oils. The enzymatic reaction involves energy-demanding steps in the membrane with the uses of structurally unknown metal active sites featuring a diiron [FeFe] center. At present, a critical barrier to understanding the membrane-associated reaction mechanism is the lack of structural information. The structural biology efforts have been challenged by technical difficulties commonly encountered in crystallization and structural determination of membrane proteins. The specific aims of the current budget cycle are to crystalize AlkB and initiate X-ray analysis to set the stage for structural determination. The long-term goals of our structural biology efforts are to provide an atomic description of AlkB structure, and to uncover the mechanisms of selective modification of hydrocarbons. The structural information will help elucidating how the unactivated C-H bonds of saturated hydrocarbons are oxidized to initiate biodegradation and biotransformation processes. The knowledge gained will be fundamental to biotechnological applications to biofuel transformation of non-edible oil feedstock. Renewable biodiesel is a promising energy carry that can be used to reduce fossil fuel dependency. The proposed research capitalizes on prior BES-supported efforts on over-expression and purification of AlkB to explore the inner workings of a bioenergy-relevant membrane-bound enzyme.
Quantum bounds for ordered searching and sorting
Hoyer, P; Shi, Y; Hoyer, Peter; Neerbek, Jan; Shi, Yaoyun
2001-01-01
We consider the quantum complexities of searching an ordered list and sorting an un-ordered list. For searching an ordered list of N elements, we prove a lower bound of \\frac{1}{\\pi}(\\ln(N)-1) on the number of oracle queries that access the list elements. This improves the previously best lower bound of ({1/12}\\log_2(N) - O(1)) due to Ambainis. For sorting N numbers, we prove a lower bound of \\frac{N}{2\\pi}(\\ln(N)-1) on the number of binary comparisons. The previously best lower bound is \\Omega(N). Our proofs are based on a weighted all-pairs inner product argument, and our results generalize to bounded error quantum algorithms. Both results are proven in the so-called quantum black box model, a quantum analogue of classical decision trees. In addition to our lower bound results, we give an exact quantum algorithm for ordered searching using (\\log_3(N) + O(1)) queries, which is roughly 0.631 \\log_2(N). Although our algorithm is worse than that of Farhi, Goldstone, Gutmann and Sipser, which makes 0.526 \\log_2(...
Parallel Branch-and-Bound Methods for the Job Shop Scheduling
DEFF Research Database (Denmark)
Clausen, Jens; Perregaard, Michael
1998-01-01
Job-shop scheduling (JSS) problems are among the more difficult to solve in the class of NP-complete problems. The only successful approach has been branch-and-bound based algorithms, but such algorithms depend heavily on good bound functions. Much work has been done to identify such functions...... for the JSS problem, but with limited success. Even with recent methods, it is still not possible to solve problems substantially larger than 10 machines and 10 jobs. In the current study, we focus on parallel methods for solving JSS problems. We implement two different parallel branch-and-bound algorithms...
2011-01-01
This thesis develops a new FEM based algorithm for shakedown analysis of structures made of elastic plastic bounded linearly kinematic hardening material. Its concept can be briefly described as: Hardening law is simulated using a two-surface plastic model. One yield surface is the initial surface, defined by yield stress sigma_y, and the other one is the bounding surface, defined by ultimate strength sigma_u. The initial surface can translate inside the bounding surface without changing its ...
Error bounds from extra precise iterative refinement
Energy Technology Data Exchange (ETDEWEB)
Demmel, James; Hida, Yozo; Kahan, William; Li, Xiaoye S.; Mukherjee, Soni; Riedy, E. Jason
2005-02-07
We present the design and testing of an algorithm for iterative refinement of the solution of linear equations, where the residual is computed with extra precision. This algorithm was originally proposed in the 1960s [6, 22] as a means to compute very accurate solutions to all but the most ill-conditioned linear systems of equations. However two obstacles have until now prevented its adoption in standard subroutine libraries like LAPACK: (1) There was no standard way to access the higher precision arithmetic needed to compute residuals, and (2) it was unclear how to compute a reliable error bound for the computed solution. The completion of the new BLAS Technical Forum Standard [5] has recently removed the first obstacle. To overcome the second obstacle, we show how a single application of iterative refinement can be used to compute an error bound in any norm at small cost, and use this to compute both an error bound in the usual infinity norm, and a componentwise relative error bound. We report extensive test results on over 6.2 million matrices of dimension 5, 10, 100, and 1000. As long as a normwise (resp. componentwise) condition number computed by the algorithm is less than 1/max{l_brace}10,{radical}n{r_brace} {var_epsilon}{sub w}, the computed normwise (resp. componentwise) error bound is at most 2 max{l_brace}10,{radical}n{r_brace} {center_dot} {var_epsilon}{sub w}, and indeed bounds the true error. Here, n is the matrix dimension and w is single precision roundoff error. For worse conditioned problems, we get similarly small correct error bounds in over 89.4% of cases.
Fourier Series Approximations to J2-Bounded Equatorial Orbits
Directory of Open Access Journals (Sweden)
Wei Wang
2014-01-01
Full Text Available The current paper offers a comprehensive dynamical analysis and Fourier series approximations of J2-bounded equatorial orbits. The initial conditions of heterogeneous families of J2-perturbed equatorial orbits are determined first. Then the characteristics of two types of J2-bounded orbits, namely, pseudo-elliptic orbit and critical circular orbit, are studied. Due to the ambiguity of the closed-form solutions which comprise the elliptic integrals and Jacobian elliptic functions, showing little physical insight into the problem, a new scheme, termed Fourier series expansion, is adopted for approximation herein. Based on least-squares fitting to the coefficients, the solutions are expressed with arbitrary high-order Fourier series, since the radius and the flight time vary periodically as a function of the polar angle. As a consequence, the solutions can be written in terms of elementary functions such as cosines, rather than complex mathematical functions. Simulations enhance the proposed approximation method, showing bounded and negligible deviations. The approximation results show a promising prospect in preliminary orbits design, determination, and transfers for low-altitude spacecrafts.
A Bound on Equipartition of Energy
Masi, Nicolo'
2011-01-01
In this article I want to demonstrate that the time-scale constraints for a thermodynamic system imply the new concept of equipartition of energy bound (EEB) or, more generally, a thermodynamical bound for the partition of energy. This means that I theorize and discuss the possibility to put an upper limit to the equipartition factor for a gas of particles. This could be interpreted as a sort of transcription of the entropy bounds from quantum-holographic sector. The number 4.93, i.e. the EEB, obtained from a comparison between the Margolus-Levitin quantum theorem and the TTT bound for relaxation times by Hod, seems like a special value for the thermodynamics of particle systems. This bound has been related to the idea of an extremal statistics and independently traced in a statistical mechanics framework. In fact, I identified a type of fluid that is capable of reaching to saturate the limit value I obtained for the equipartition factor. This was done by analyzing the mathematical behavior of the distributio...
Conformational phases of membrane bound cytoskeletal filaments
Quint, David A.; Grason, Gregory; Gopinathan, Ajay
2013-03-01
Membrane bound cytoskeletal filaments found in living cells are employed to carry out many types of activities including cellular division, rigidity and transport. When these biopolymers are bound to a membrane surface they may take on highly non-trivial conformations as compared to when they are not bound. This leads to the natural question; What are the important interactions which drive these polymers to particular conformations when they are bound to a surface? Assuming that there are binding domains along the polymer which follow a periodic helical structure set by the natural monomeric handedness, these bound conformations must arise from the interplay of the intrinsic monomeric helicity and membrane binding. To probe this question, we study a continuous model of an elastic filament with intrinsic helicity and map out the conformational phases of this filament for various mechanical and structural parameters in our model, such as elastic stiffness and intrinsic twist of the filament. Our model allows us to gain insight into the possible mechanisms which drive real biopolymers such as actin and tubulin in eukaryotes and their prokaryotic cousins MreB and FtsZ to take on their functional conformations within living cells.
Introduction to QCD - a bound state perspective
Hoyer, Paul
2011-01-01
These lecture notes focus on the bound state sector of QCD. Motivated by data which suggests that the strong coupling \\alpha_s(Q) freezes at low Q, and by similarities between the spectra of hadrons and atoms, I discuss if and how QCD bound states may be treated perturbatively. I recall the basic principles of perturbative gauge theory bound states at lowest order in the \\hbar expansion. Born level amplitudes are insensitive to the i\\epsilon prescription of propagators, which allows to eliminate the Z-diagrams of relativistic, time-ordered Coulomb interactions. The Dirac wave function thus describes a single electron which propagates forward in time only, even though the bound state has any number of pair constituents when Feynman propagators are used. In the absence of an external potential, states that are bound by the Coulomb attraction of their constituents can be analogously described using only their valence degrees of freedom. The instantaneous A^0 field is determined by Gauss' law for each wave functi...
Johnson Type Bounds on Constant Dimension Codes
Xia, Shu-Tao
2007-01-01
Very recently, an operator channel was defined by Koetter and Kschischang when they studied random network coding. They also introduced constant dimension codes and demonstrated that these codes can be employed to correct errors and/or erasures over the operator channel. Constant dimension codes are equivalent to the so-called linear authentication codes introduced by Wang, Xing and Safavi-Naini when constructing distributed authentication systems in 2003. In this paper, we study constant dimension codes. It is shown that Steiner structures are optimal constant dimension codes achieving the Wang-Xing-Safavi-Naini bound. Furthermore, we show that constant dimension codes achieve the Wang-Xing-Safavi-Naini bound if and only if they are certain Steiner structures. Then, we derive two Johnson type upper bounds, say I and II, on constant dimension codes. The Johnson type bound II slightly improves on the Wang-Xing-Safavi-Naini bound. Finally, we point out that a family of known Steiner structures is actually a fam...
Space Lower Bounds for Online Pattern Matching
Clifford, Raphael; Porat, Ely; Sach, Benjamin
2011-01-01
We present space lower bounds for online pattern matching under a number of different distance measures. Given a pattern of length m and a text that arrives one character at a time, the online pattern matching problem is to report the distance between the pattern and a sliding window of the text as soon as the new character arrives. We require that the correct answer is given at each position with constant probability. We give Omega(m) bit space lower bounds for L_1, L_2, L_\\infty, Hamming, edit and swap distances as well as for any algorithm that computes the cross-correlation/convolution. We then show a dichotomy between distance functions that have wildcard-like properties and those that do not. In the former case which includes, as an example, pattern matching with character classes, we give Omega(m) bit space lower bounds. For other distance functions, we show that there exist space bounds of Omega(log m) and O(log^2 m) bits. Finally we discuss space lower bounds for non-binary inputs and show how in som...
Lower Bounds on Q for Finite Size Antennas of Arbitrary Shape
DEFF Research Database (Denmark)
Kim, Oleksiy S.
2016-01-01
The problem of the lower bound on the radiation Q for an arbitrarily shaped finite size antenna of non-zero volume is formulated in terms of equivalent electric and magnetic currents densities distributed on a closed surface coinciding with antenna exterior surface. When these equivalent currents...
Institute of Scientific and Technical Information of China (English)
无
2001-01-01
This paper analyzes some problems arising in determining the mails Whole Delivery Standard of Time Bound (WDSTB) at present, and further on the basis of the postal central office system currently in practice, puts forward the principle, reflection and the concrete approaches in determining the Delivery Standard of Time Bound (DSTB).
Numerical simulation of wall-bounded turbulent shear flows
Moin, P.
1982-01-01
Developments in three dimensional, time dependent numerical simulation of turbulent flows bounded by a wall are reviewed. Both direct and large eddy simulation techniques are considered within the same computational framework. The computational spatial grid requirements as dictated by the known structure of turbulent boundary layers are presented. The numerical methods currently in use are reviewed and some of the features of these algorithms, including spatial differencing and accuracy, time advancement, and data management are discussed. A selection of the results of the recent calculations of turbulent channel flow, including the effects of system rotation and transpiration on the flow are included.
Relaxing neutrino mass bounds by a running cosmological constant
Energy Technology Data Exchange (ETDEWEB)
Bauer, F.; Schrempp, L.
2007-11-15
We establish an indirect link between relic neutrinos and the dark energy sector which originates from the vacuum energy contributions of the neutrino quantum fields. Via renormalization group effects they induce a running of the cosmological constant with time which dynamically influences the evolution of the cosmic neutrino background. We demonstrate that the resulting reduction of the relic neutrino abundance allows to largely evade current cosmological neutrino mass bounds and discuss how the scenario might be probed by the help of future large scale structure surveys and Planck data. (orig.)
Energy Technology Data Exchange (ETDEWEB)
Bechtle, Philip; Weiglein, Georg [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Brein, Oliver [Freiburg Univ. (Germany). Physikalisches Inst.; Heinemeyer, Sven [Instituto de Fisica de Cantabria (CSIC-UC), Santander (Spain); Williams, Karina [Bonn Univ. (Germany). Bethe Center for Theoretical Physics
2011-01-15
We introduce version 2.0.0 of the computer program HiggsBounds. The program tests neutral and charged Higgs sectors of arbitrary models against the current exclusion bounds from LEP and the Tevatron. As input, it requires a selection of model predictions, such as Higgs masses, branching ratios, effective couplings and total decay widths. The program uses the expected and observed topological cross section limits from the Higgs searches to determine whether a given parameter scenario of a model is excluded at the 95% C.L. by those searches. Version 2.0.0 includes 39/53 LEP/Tevatron Higgs search analyses, compared to 13/36 in the previous release (1.2.0). Among the newly included analyses are LEP searches for neutral Higgs bosons (H) decaying invisibly or into hadrons, LEP searches via the production modes {tau}{sup +}{tau}{sup -}H and b anti bH, Tevatron searches via t anti tH, and LEP and Tevatron searches for charged Higgs bosons. Also, all Tevatron results presented at the ICHEP'10 are included in version 2.0.0. In this note, we explain the basic ideas behind the implementation of HiggsBounds and provide a list of search topologies implemented in version 2.0.0. Furthermore, we apply HiggsBounds 2.0.0 to (a) determine the allowed Higgs mass range for a simple 4th generation model, (b) update/reproduce LEP/Tevatron Higgs exclusion plots for the MSSM m{sub h}{sup max} benchmark scenario, and (c) show exclusion results for the scalar sector of the Randall-Sundrum model. (orig.)
Energy Technology Data Exchange (ETDEWEB)
Bechtle, Philip; Weiglein, Georg [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Brein, Oliver [Freiburg Univ. (Germany). Physikalisches Inst.; Heinemeyer, Sven [Instituto de Fisica de Cantabria (CSIC-UC), Santander (Spain); Williams, Karina [Bonn Univ. (Germany). Bethe Center for Theoretical Physics
2011-01-15
We introduce version 2.0.0 of the computer program HiggsBounds. The program tests neutral and charged Higgs sectors of arbitrary models against the current exclusion bounds from LEP and the Tevatron. As input, it requires a selection of model predictions, such as Higgs masses, branching ratios, effective couplings and total decay widths. The program uses the expected and observed topological cross section limits from the Higgs searches to determine whether a given parameter scenario of a model is excluded at the 95% C.L. by those searches. Version 2.0.0 includes 39/53 LEP/Tevatron Higgs search analyses, compared to 13/36 in the previous release (1.2.0). Among the newly included analyses are LEP searches for neutral Higgs bosons (H) decaying invisibly or into hadrons, LEP searches via the production modes {tau}{sup +}{tau}{sup -}H and b anti bH, Tevatron searches via t anti tH, and LEP and Tevatron searches for charged Higgs bosons. Also, all Tevatron results presented at the ICHEP'10 are included in version 2.0.0. In this note, we explain the basic ideas behind the implementation of HiggsBounds and provide a list of search topologies implemented in version 2.0.0. Furthermore, we apply HiggsBounds 2.0.0 to (a) determine the allowed Higgs mass range for a simple 4th generation model, (b) update/reproduce LEP/Tevatron Higgs exclusion plots for the MSSM m{sub h}{sup max} benchmark scenario, and (c) show exclusion results for the scalar sector of the Randall-Sundrum model. (orig.)
Bounds on localisable information via semidefinite programming
Synak, B; Horodecki, M; Synak, Barbara; Horodecki, Karol; Horodecki, Michal
2004-01-01
We investigate so-called localisable information of bipartite states and a parallel notion of information deficit. Localisable information is defined as the amount of information that can be concentrated by means of classical communication and local operations where only maximally mixed states can be added for free. The information deficit is defined as difference between total information contents of the state and localisable information. We consider a larger class of operations: the so called PPT operations, which in addition preserve maximally mixed state (PPT-PMM operations). We formulate the related optimization problem as sedmidefnite program with suitable constraints. We then provide bound for fidelity of transition of a given state into product pure state on Hilbert space of dimension d. This allows to obtain general upper bound for localisable information (and also for information deficit). We calculated the bounds exactly for Werner states and isotropic states in any dimension. Surprisingly it turns...
Bound States in Boson Impurity Models
Shi, Tao; Wu, Ying-Hai; González-Tudela, A.; Cirac, J. I.
2016-04-01
The formation of bound states involving multiple particles underlies many interesting quantum physical phenomena, such as Efimov physics or superconductivity. In this work, we show the existence of an infinite number of such states for some boson impurity models. They describe free bosons coupled to an impurity and include some of the most representative models in quantum optics. We also propose a family of wave functions to describe the bound states and verify that it accurately characterizes all parameter regimes by comparing its predictions with exact numerical calculations for a one-dimensional tight-binding Hamiltonian. For that model, we also analyze the nature of the bound states by studying the scaling relations of physical quantities, such as the ground-state energy and localization length, and find a nonanalytical behavior as a function of the coupling strength. Finally, we discuss how to test our theoretical predictions in experimental platforms, such as photonic crystal structures and cold atoms in optical lattices.
Bound States Of Supersymmetric Black Holes
Britto-Pacumio, R A
2002-01-01
The quantum mechanics of N slowly-moving supersymmetric black holes in five dimensions is considered. A divergent continuum of states describing arbitrarily closely bound black holes with arbitrarily small excitation energies is found. A superconformal structure appears at low energies and can be used to define a topological index counting the weighted number of supersymmetric bound states. It is shown that the index is determined from the dimensions of certain cohomology classes on the symmetric product of N copies of R4. This bound state index is computed exactly for two and three black holes. The required regulator for the infrared continuum of near-coincident black holes is chosen in accord with the enhanced superconformal symmetry.
Bounded link prediction in very large networks
Cui, Wei; Pu, Cunlai; Xu, Zhongqi; Cai, Shimin; Yang, Jian; Michaelson, Andrew
2016-09-01
Evaluating link prediction methods is a hard task in very large complex networks due to the prohibitive computational cost. However, if we consider the lower bound of node pairs' similarity scores, this task can be greatly optimized. In this paper, we study CN index in the bounded link prediction framework, which is applicable to enormous heterogeneous networks. Specifically, we propose a fast algorithm based on the parallel computing scheme to obtain all node pairs with CN values larger than the lower bound. Furthermore, we propose a general measurement, called self-predictability, to quantify the performance of similarity indices in link prediction, which can also indicate the link predictability of networks with respect to given similarity indices.
η-nuclear bound states revisited
Friedman, E.; Gal, A.; Mareš, J.
2013-10-01
The strong energy dependence of the s-wave ηN scattering amplitude at and below threshold, as evident in coupled-channels K-matrix fits and chiral models that incorporate the S11N* (1535) resonance, is included self-consistently in η-nuclear bound-state calculations. This approach, applied recently in calculations of kaonic atoms and Kbar-nuclear bound states, is found to impose stronger constraints than ever on the onset of η-nuclear binding, with a minimum value of ReaηN ≈ 0.9 fm required to accommodate an η-4He bound state. Binding energies and widths of η-nuclear states are calculated within several underlying ηN models for nuclei across the periodic table, including Mg25η for which some evidence was proposed in a recent COSY experiment.
Narrow deeply bound K- atomic states
Friedman, E.; Gal, A.
1999-07-01
Using optical potentials fitted to a comprehensive set of strong interaction level shifts and widths in K- atoms, we predict that the K- atomic levels which are inaccessible in the atomic cascade process are generally narrow, spanning a range of widths about 50-1500 keV over the entire periodic table. The mechanism for this narrowing is different from the mechanism for narrowing of pionic atom levels. Examples of such `deeply bound' K- atomic states are given, showing that in many cases these states should be reasonably well resolved. Several reactions which could be used to form these `deeply bound' states are mentioned. Narrow deeply bound states are expected also in overlinep atoms.
Shedding of cell membrane-bound proteoglycans.
Nam, Eon Jeong; Park, Pyong Woo
2012-01-01
Membrane-bound proteoglycans function primarily as coreceptors for many glycosaminoglycan (GAG)-binding ligands at the cell surface. The majority of membrane-bound proteoglycans can also function as soluble autocrine or paracrine effectors as their extracellular domains, replete with all GAG chains, are enzymatically cleaved and released from the cell surface by ectodomain shedding. In particular, the ectodomain shedding of syndecans, a major family of cell surface heparan sulfate proteoglycans, is an important posttranslational mechanism that modulates diverse pathophysiological processes. Syndecan shedding is a tightly controlled process that regulates the onset, progression, and resolution of various infectious and noninfectious inflammatory diseases. This review describes methods to induce and measure the shedding of cell membrane-bound proteoglycans, focusing on syndecan shedding as a prototypic example.
Creed, Peter A.; Patton, Wendy; Hood, Michelle
2010-01-01
We surveyed 506 Australian high school students on career development (exploration, planning, job-knowledge, decision-making, indecision), personal functioning (well-being, self-esteem, life satisfaction, school satisfaction) and control variables (parent education, school achievement), and tested differences among work-bound, college-bound and…
Institute of Scientific and Technical Information of China (English)
曲腾飞
2013-01-01
The paper through data method, questionnaire survey method and other methods to study on the status of outward bound training in Henan college sports teaching, and puts forward some constructive suggestions, in order to provide scientific and effective method to deepen the teaching reform of college sports.% 本文通过资料法、问卷调查法等方法对河南高校体育课开展素质拓展训练的现状进行研究，并提出一些建设性的建议，旨在为深化高校体育教学改革提供科学有效的方法。
Lower bounds for unbounded operators and semigroups
2016-01-01
Let $A$ be an unbounded operator on a Banach space $X$. It is sometimes useful to improve the operator $A$ by extending it to an operator $B$ on a larger Banach space $Y$ with smaller spectrum. It would be preferable to do this with some estimates for the resolvent of $B$, and also to extend bounded operators related to $A$, for example a semigroup generated by $A$. When $X$ is a Hilbert space, one may also want $Y$ to be Hilbert space. Results of this type for bounded operators have been giv...
Generalized Bounds on Majoron-neutrino couplings
Tomás, R; Valle, José W F
2001-01-01
We discuss limits on neutrino-Majoron couplings both from laboratory experiments as well as from astrophysics. They apply to the simplest class of Majoron models which covers a variety of possibilities where neutrinos acquire mass either via a seesaw-type scheme or via radiative corrections. By adopting a general framework including CP phases we generalize bounds obtained previously. The combination of complementary bounds enables us to obtain a highly non-trivial exclusion region in the parameter space. We find that the future double beta project GENIUS, together with constraints based on supernova energy release arguments, could restrict neutrino-Majoron couplings down to the 10^{-7} level.
Upper bounds on the photon mass
Accioly, Antonio; Scatena, Eslley; 10.1103/PhysRevD.82.065026
2010-01-01
The effects of a nonzero photon rest mass can be incorporated into electromagnetism in a simple way using the Proca equations. In this vein, two interesting implications regarding the possible existence of a massive photon in nature, i.e., tiny alterations in the known values of both the anomalous magnetic moment of the electron and the gravitational deflection of electromagnetic radiation, are utilized to set upper limits on its mass. The bounds obtained are not as stringent as those recently found; nonetheless, they are comparable to other existing bounds and bring new elements to the issue of restricting the photon mass.
Weakly bound systems, continuum effects, and reactions
Jaganathen, Y; Ploszajczak, M
2012-01-01
Structure of weakly bound/unbound nuclei close to particle drip lines is different from that around the valley of beta stability. A comprehensive description of these systems goes beyond standard Shell Model and demands an open quantum system description of the nuclear many-body system. We approach this problem using the Gamow Shell Model which provides a fully microscopic description of bound and unbound nuclear states, nuclear decays, and reactions. We present in this paper the first application of the GSM for a description of the elastic and inelastic scattering of protons on 6He.
Bounded distortion homeomorphisms on ultrametric spaces
Hughes, Bruce; Morón, Manuel A
2010-01-01
It is well-known that quasi-isometries between R-trees induce power quasi-symmetric homeomorphisms between their ultrametric end spaces. This paper investigates power quasi-symmetric homeomorphisms between bounded, complete, uniformly perfect, ultrametric spaces (i.e., those ultrametric spaces arising up to similarity as the end spaces of bushy trees). A bounded distortion property is found that characterizes power quasi-symmetric homeomorphisms between such ultrametric spaces that are also pseudo-doubling. Moreover, examples are given showing the extent to which the power quasi-symmetry of homeomorphisms is not captured by the quasiconformal and bi-H\\"older conditions for this class of ultrametric spaces.
Learning within bounds and dream sleep
Geszti, T.; Pazmandi, F.
1987-12-01
In a bounded-synapses version of Hopfield's model (1984) for neural networks the quasienergy of a given memory, which is approximately equal to the depth of the corresponding energy well is calculated exactly by treating the change of a synaptic strength on learning as a random walk within bounds. Attractors corresponding to stored memories are found to be considerably flattened before serious retrieval errors arise. This allows dream sleep to be interpreted as random recall and relearning of fresh strong memories, in order to stack them on top of weak incidental memory imprints of a day.
Irreversibility for all bound entangled states
Yang, D; Horodecki, R; Synak-Radtke, B; Yang, Dong; Horodecki, Michal; Horodecki, Ryszard; Synak-Radtke, Barbara
2005-01-01
We derive a new inequality for entanglement for a mixed four-partite state. Employing this inequality, we present a one-shot lower bound for entanglement cost and prove that entanglement cost is strictly larger than zero for any entangled state. We demonstrate that irreversibility occurs in the process of formation for all non-distillable entangled states. In this way we solve a long standing problem, of how "real" is entanglement of bound entangled states. Using the new inequality we also prove impossibility of local-cloning and local-deleting of a known entangled state.
Proof of a Quantum Bousso Bound
Bousso, Raphael; Fisher, Zachary; Maldacena, Juan
2014-01-01
We prove the generalized Covariant Entropy Bound, $\\Delta S\\leq (A-A')/4G\\hbar$, for light-sheets with initial area $A$ and final area $A'$. The entropy $\\Delta S$ is defined as a difference of von Neumann entropies of an arbitrary state and the vacuum, with both states restricted to the light-sheet under consideration. The proof applies to free fields, in the limit where gravitational backreaction is small. We do not assume the null energy condition. In regions where it is violated, we find that the bound is protected by the defining property of light-sheets: that their null generators are nowhere expanding.
Photon-assisted tunneling through a topological superconductor with Majorana bound states
Energy Technology Data Exchange (ETDEWEB)
Tang, Han-Zhao; Zhang, Ying-Tao, E-mail: zhangyt@mail.hebtu.edu.cn [College of Physics, Hebei Normal University, Shijiazhuang 050024 (China); Liu, Jian-Jun, E-mail: liujj@mail.hebtu.edu.cn [College of Physics, Hebei Normal University, Shijiazhuang 050024 (China); Department of Physics, Shijiazhuang University, Shijiazhuang 050035 (China)
2015-12-15
Employing the Keldysh Nonequilibrium Green’s function method, we investigate time-dependent transport through a topological superconductor with Majorana bound states in the presence of a high frequency microwave field. It is found that Majorana bound states driven by photon-assisted tunneling can absorb(emit) photons and the resulting photon-assisted tunneling side band peaks can split the Majorana bound state that then appears at non-zero bias. This splitting breaks from the current opinion that Majorana bound states appear only at zero bias and thus provides a new experimental method for detecting Majorana bound states in the Non-zero-energy mode. We not only demonstrate that the photon-assisted tunneling side band peaks are due to Non-zero-energy Majorana bound states, but also that the height of the photon-assisted tunneling side band peaks is related to the intensity of the microwave field. It is further shown that the time-varying conductance induced by the Majorana bound states shows negative values for a certain period of time, which corresponds to a manifestation of the phase coherent time-varying behavior in mesoscopic systems.
Computing Bounds on Resource Levels for Flexible Plans
Muscvettola, Nicola; Rijsman, David
2009-01-01
A new algorithm efficiently computes the tightest exact bound on the levels of resources induced by a flexible activity plan (see figure). Tightness of bounds is extremely important for computations involved in planning because tight bounds can save potentially exponential amounts of search (through early backtracking and detection of solutions), relative to looser bounds. The bound computed by the new algorithm, denoted the resource-level envelope, constitutes the measure of maximum and minimum consumption of resources at any time for all fixed-time schedules in the flexible plan. At each time, the envelope guarantees that there are two fixed-time instantiations one that produces the minimum level and one that produces the maximum level. Therefore, the resource-level envelope is the tightest possible resource-level bound for a flexible plan because any tighter bound would exclude the contribution of at least one fixed-time schedule. If the resource- level envelope can be computed efficiently, one could substitute looser bounds that are currently used in the inner cores of constraint-posting scheduling algorithms, with the potential for great improvements in performance. What is needed to reduce the cost of computation is an algorithm, the measure of complexity of which is no greater than a low-degree polynomial in N (where N is the number of activities). The new algorithm satisfies this need. In this algorithm, the computation of resource-level envelopes is based on a novel combination of (1) the theory of shortest paths in the temporal-constraint network for the flexible plan and (2) the theory of maximum flows for a flow network derived from the temporal and resource constraints. The measure of asymptotic complexity of the algorithm is O(N O(maxflow(N)), where O(x) denotes an amount of computing time or a number of arithmetic operations proportional to a number of the order of x and O(maxflow(N)) is the measure of complexity (and thus of cost) of a maximumflow
BOUNDS FOR THE ZEROS OF POLYNOMIALS
Institute of Scientific and Technical Information of China (English)
W. M. Shah; A.Liman
2004-01-01
Let P(z) =n∑j=0 ajzj be a polynomial of degree n. In this paper we prove a more general result which interalia improves upon the bounds of a class of polynomials. We also prove a result which includes some extensions and generalizations of Enestrom-Kakeya theorem.
Bounds on transverse momentum dependent distribution functions
Henneman, A A
2001-01-01
When more than one hadron takes part in a hard process, an extended set of quark distribution and fragmentation functions becomes relevant. In this talk, the derivation of Soffer-like bounds for these functions, in the case of a spin-1/2 target, is sketched and some of their aspects are discussed.
Bounds on transverse momentum dependent distribution functions
Henneman, A.
2000-01-01
When more than one hadron takes part in a hard process, an extended set of quark distribution and fragmentation functions becomes relevant. In this talk, the derivation of Soffer-like bounds for these functions, in the case of a spin-1/2 target, is sketched and some of their aspects are discussed.
Bounds on transverse momentum dependent distribution functions
Henneman, A.
2001-01-01
When more than one hadron takes part in a hard process, an extended set of quark distribution and fragmentation functions becomes relevant. In this talk, the derivation of Soffer-like bounds for these functions, in the case of a spin-1/2 target [1], is sketched and some of their aspects are discussed.
Bounding the bias of contrastive divergence learning
DEFF Research Database (Denmark)
Fischer, Anja; Igel, Christian
2011-01-01
Optimization based on k-step contrastive divergence (CD) has become a common way to train restricted Boltzmann machines (RBMs). The k-step CD is a biased estimator of the log-likelihood gradient relying on Gibbs sampling. We derive a new upper bound for this bias. Its magnitude depends on k...
Bounded Rationality of Generalized Abstract Fuzzy Economies
Directory of Open Access Journals (Sweden)
Lei Wang
2014-01-01
Full Text Available By using a nonlinear scalarization technique, the bounded rationality model M for generalized abstract fuzzy economies in finite continuous spaces is established. Furthermore, by using the model M, some new theorems for structural stability and robustness to (λ,ϵ-equilibria of generalized abstract fuzzy economies are proved.
Collisional properties of weakly bound heteronuclear dimers
Marcelis, B.; Kokkelmans, S.J.J.M.F.; Shlyapnikov, G.V.; Petrov, D.S.
2008-01-01
We consider collisional properties of weakly bound heteronuclear molecules (dimers) formed in a two-species mixture of atoms with a large mass difference. We focus on dimers containing light fermionic atoms as they manifest collisional stability due to an effective dimer-dimer repulsion originating
A Tight Bound for the Lamplighter Problem
Ganapathy, Murali K.; Tetali, Prasad
2006-01-01
We settle an open problem, raised by Y. Peres and D. Revelle, concerning the $L^2$ mixing time of the random walk on the lamplighter graph. We also provide general bounds relating the entropy decay of a Markov chain to the separation distance of the chain, and show that the lamplighter graphs once again provide examples of tightness of our results.
Improved Lower Bound for Online Strip Packing
Harren, Rolf; Kern, Walter
We study the online strip packing problem and derive an improved lower bound of Ͽ ≥ 2.589... for the competitive ratio of this problem. The construction is based on modified “Brown-Baker-Katseff sequences‿ (Brown et al. in Acta Inform. 18:207–225, 1982) using only two types of rectangles. In
Improved lower bound for online strip packing
Harren, Rolf; Kern, Walter
2012-01-01
In the two-dimensional strip packing problem a number of rectangles have to be packed without rotation or overlap into a strip such that the height of the strip used is minimal. The width of the rectangles is bounded by 1 and the strip has width 1 and infinite height. We study the online version of
Monotonicity and bounds on Bessel functions
Directory of Open Access Journals (Sweden)
Larry Landau
2000-07-01
Full Text Available survey my recent results on monotonicity with respect to order of general Bessel functions, which follow from a new identity and lead to best possible uniform bounds. Application may be made to the "spreading of the wave packet" for a free quantum particle on a lattice and to estimates for perturbative expansions.
Dilation volumes of sets of bounded perimeter
DEFF Research Database (Denmark)
Kiderlen, Markus; Rataj, Jan
it to determine the derivative of the contact distribution function of a stationary random closed set at zero. A variant for uncountable Q is given, too. The proofs are based on approximation of the characteristic function of A by smooth functions of bounded variation and showing corresponding formulas for them....
A Characterization of Complete Bounded Domain
Institute of Scientific and Technical Information of China (English)
殷慰萍; 苏简兵; 赵振刚
2002-01-01
@@ 1 IntroductionThis paper is concerned with biholomorphic mappings between two bounded domains D and G both in Cn.Consequently,an important question is whether the domain D is biholomorphic to G? We give an answer for this question under a very weak condition.
A PSL Bounded Model Checking Method
Institute of Scientific and Technical Information of China (English)
YU Lei; ZHAO Zongtao
2012-01-01
SAT-based bounded model checking （BMC） is introduced as an important complementary technique to OBDD-based symbolic model checking, and is an efficient verification method for parallel and reactive systems. However, until now the properties verified by bounded model checking are very finite. Temporal logic PSL is a property specification language （IEEE-1850） describing parallel systems and is divided into two parts, i.e. the linear time logic FL and the branch time logic OBE. In this paper, the specification checked by BMC is extended to PSL and its algorithm is also proposed. Firstly, define the bounded semantics of PSL, and then reduce the bounded semantics into SAT by translating PSL specification formula and the state transition relation of the system to the propositional formula A and B, respectively. Finally, verify the satisfiability of the conjunction propositional formula of A and B. The algorithm results in the translation of the existential model checking of the temporal logic PSL into the satisfiability problem of propositional formula. An example of a queue controlling circuit is used to interpret detailedly the executing procedure of the algorithm.
Concerns on Monotonic Imbalance Bounding Matching Methods
Yatracos, Yannis G.
2013-01-01
Concerns are expressed for the Monotonic Imbalance Bounding (MIB) property (Iacus et al. 2011) and for MIB matching because i) the definition of the MIB property leads to inconsistencies and the nature of the imbalance measure is not clearly defined, ii) MIB property does not generalize Equal Percent Bias Reducing (EPBR) property, iii) MIB matching does not provide statistical information available with EPBR matching.
Combined perturbation bounds:Ⅱ.Polar decompositions
Institute of Scientific and Technical Information of China (English)
2007-01-01
In this paper,we study the perturbation bounds for the polar decomposition A=QH where Q is unitary and H is Hermitian.The optimal （asymptotic） bounds obtained in previous works for the unitary factor,the Hermitian factor and singular values of A areσr2||ΔQ||F2≤||ΔA||F2, 1/2||ΔH||F2≤||ΔA||F2 and ||Δ∑||F2≤||ΔA||F2,respectively,where∑=diag（σ1,σ2,...,σr,0,...,0） is the singular value matrix of A andσr denotes the smallest nonzero singular value.Here we present some new combined （asymptotic） perturbation boundsσr2||ΔQ||F2+1/2||ΔH||F2≤||ΔA||F2 andσr2||ΔQ||F2+||Δ∑||F2≤||ΔA||F2 which are optimal for each factor.Some corresponding absolute perturbation bounds are also given.
Lower bounds for polynomials using geometric programming
Ghasemi, Mehdi
2011-01-01
We make use of a result of Hurwitz and Reznick, and a consequence of this result due to Fidalgo and Kovacec, to determine a new sufficient condition for a polynomial $f\\in\\mathbb{R}[X_1,...,X_n]$ of even degree to be a sum of squares. This result generalizes a result of Lasserre and a result of Fidalgo and Kovacec, and it also generalizes the improvements of these results given in [6]. We apply this result to obtain a new lower bound $f_{gp}$ for $f$, and we explain how $f_{gp}$ can be computed using geometric programming. The lower bound $f_{gp}$ is generally not as good as the lower bound $f_{sos}$ introduced by Lasserre and Parrilo and Sturmfels, which is computed using semidefinite programming, but a run time comparison shows that, in practice, the computation of $f_{gp}$ is much faster. The computation is simplest when the highest degree term of $f$ has the form $\\sum_{i=1}^n a_iX_i^{2d}$, $a_i>0$, $i=1,...,n$. The lower bounds for $f$ established in [6] are obtained by evaluating the objective function ...
Properties of Excitons Bound to Ionized Donors
DEFF Research Database (Denmark)
Skettrup, Torben; Suffczynski, M.; Gorzkowski, W.
1971-01-01
Binding energies, interparticle distances, oscillator strengths, and exchange corrections are calculated for the three-particle complex corresponding to an exciton bound to an ionized donor. The results are given as functions of the mass ratio of the electron and hole. Binding of the complex is o...
Qp-spaces on bounded symmetric domains
Directory of Open Access Journals (Sweden)
Jonathan Arazy
2008-01-01
Full Text Available We generalize the theory of Qp spaces, introduced on the unit disc in 1995 by Aulaskari, Xiao and Zhao, to bounded symmetric domains in Cd, as well as to analogous Moebius-invariant function spaces and Bloch spaces defined using higher order derivatives; the latter generalization contains new results even in the original context of the unit disc.
Covariant Entropy Bound and Padmanabhan's Emergent Paradigm
Hadi, H; Darabi, F
2016-01-01
The covariant entropy conjecture is invariant under time reversal and consequently its origin must be statistical rather than thermodynamical. This may impose a fundamental constraint on the number of degrees of freedom in nature. Indeed, the covariant entropy bound imposes an upper entropy bound for any physical system. Considering a cosmological system, we show that Padmanabhan's emergent paradigm, which indicates that the emergence of cosmic space is due to the discrepancy between the surface and bulk degrees of freedom, leads to a lower entropy bound. The lower and upper entropy bounds may coincide on the apparent horizon for the radiation field and dark energy with the equations of state $\\omega=\\frac{1}{3}$ and $\\omega=-1$, respectively. Moreover, the maximal entropy inside the apparent horizon occurs when it is filled completely by the radiation field or dark energy. It turns out that for dark energy case (pure de Sitter space)\\ the holographic principle is satisfied in the sense that the number of deg...
A cosmological bound on radiative neutrino lifetime
Mirizzi, A.; Montanino, D.; Serpico, P. D.
2008-07-01
Neutrino oscillation experiments and direct bounds on absolute masses constrain neutrino mass differences to fall into the microwave energy range, for most of the allowed parameter space. As a consequence of these recent phenomenological advances, older constraints on radiative neutrino decays based on diffuse background radiations and assuming strongly hierarchical masses in the eV range are now outdated. We thus derive new bounds on the radiative neutrino lifetime using the high precision cosmic microwave background spectral data collected by the FIRAS instrument on board of COBE. The lower bound on neutrino lifetime is between a few ×1019 s and ~ 5 × 1020 s, depending on the neutrino mass ordering and on the absolute neutrino mass scale. However, due to phase space limitations, the upper bound on the effective magnetic moment mediating the decay is not better than ~10-8 μB. We also comment about possible improvements of these limits, by means of recent diffuse infrared photon background data.
Revisiting cosmological bounds on radiative neutrino lifetime
Mirizzi, A; Serpico, Pasquale Dario
2007-01-01
Neutrino oscillation experiments and direct bounds on absolute masses constrain neutrino mass differences to fall into the microwave energy range, for most of the allowed parameter space. As a consequence of these recent phenomenological advances, older constraints on radiative neutrino decays based on diffuse background radiations and assuming strongly hierarchical masses in the eV range are now outdated. We thus derive new bounds on the radiative neutrino lifetime using the high precision cosmic microwave background spectral data collected by the FIRAS instrument on board of COBE. The lower bound on the lifetime is between a few x 10^19 s and 5 x 10^20 s, depending on the neutrino mass ordering and on the absolute mass scale. However, due to phase space limitations, the upper bound in terms of the effective magnetic moment mediating the decay is not better than ~ 10^-8 Bohr magnetons. We also comment about possible improvements of these limits, by means of recent diffuse infrared photon background data. We ...
New Spectral Features from Bound Dark Matter
DEFF Research Database (Denmark)
Catena, Riccardo; Kouvaris, Chris
2016-01-01
We demonstrate that dark matter particles gravitationally bound to the Earth can induce a characteristic nuclear recoil signal at low energies in direct detection experiments. The new spectral feature we predict can provide the ultimate smoking gun for dark matter discovery for experiments...
Lower Bound for Visual Cryptography Schemes
Cheraghi, Abbas
2007-01-01
For a given visual cryptography scheme, it is possible to present a basis matrices for it and most of constructions are based on basis matrices. In this paper we introduce a lower bound for the pixel expansion of visual cryptography schemes with basis matrices. To make the main theorem more flexible, we will introduce a lower bound based on induced matchings of hypergraph of qualified sets. As an application, we present an algebraic proof for the fact that the pixel expansion of basis matrices of any $k$ out of $k$ scheme is at least $2^{k-1}$. In the sequel, we present a lower bound for the pixel expansion of a given graph access structure in term of maximum number of edges in an induced matching. Finally, we show that the minimum pixel expansion of basis matrices of graph access structure $P_n$ is exactly $\\lceil \\frac{n+1}{2}\\rceil$ and this shows the lower bound mentioned in the main theorem is sharp.
Sharp Bounds for Symmetric and Asymmetric Diophantine Approximation
Institute of Scientific and Technical Information of China (English)
Cornelis KRAAIKAMP; Ionica SMEETS
2011-01-01
In 2004,Tong found bounds for the approximation quality of a regular continued fraction convergent to a rational number,expressed in bounds for both the previous and next approximation.The authors sharpen his results with a geometric method and give both sharp upper and lower bounds.The asymptotic frequencies that these bounds occur are also calculated.
Analysis of upper and lower bounds of the frame noise in linear detector arrays
Jaggi, S.
1991-01-01
This paper estimates the upper and lower bounds of the frame noise of a linear detector array that uses a one-dimensional scan pattern. Using chi-square distribution, it is analytically shown why it is necessary to use the average of the variances and not the average of the standard deviations to estimate these bounds. Also, a criteria for determining whether any excessively noisy lines exist among the detectors is derived from these bounds. Using a Gaussian standard random variable generator, these bounds are demonstrated to be accurate within the specified confidence interval. A silicon detector array is then used for actual dark current measurements. The criterion developed for determination of noisy detectors is checked on the experimentally obtained data.
Loophole in Search Beyond Grossman—Nir Bound
Hou, George W. S.
2017-01-01
The Grossman-Nir bound concept is robust, but the common perception of may be circumvented. Because of the blinding Kπ2(3) decay, K+ decay experiments such as E787/E949 and the currently running NA62 kinematically exclude the “blinding zone”. This offers an opportunity for the currently running KOTO experiment. With no kinematic control, if the KOTO experiment is able to veto all true background, it may discover KL → π 0 + X 0, where X 0 is an invisible “dark” boson with mass mX 0 ∼ mπ 0. This could happen with 2015 data at hand, which supposedly should allow KOTO to reach nominal GN bound sensitivity. An explicit model of gauged L μ ‑ Lr , linked with muon g ‑ 2 hence with very light Z‧, is given. Adding vector-like quarks that mix with usual quarks, W-boson loops induce s → dZ‧ and b → sZ‧ transitions. Besides realizing the scenario, the model provides further illustration of potential impact. Given that usual dark bosons linked with the photon are tightly constrained, KOTO has a unique opportunity to probe the muon-related dark sector.
Bounded sets in the range of an X∗∗-valued measure with bounded variation
B. Marchena; Piñeiro, C.
2000-01-01
Let X be a Banach space and A⊂X an absolutely convex, closed, and bounded set. We give some sufficient and necessary conditions in order that A lies in the range of a measure valued in the bidual space X∗∗ and having bounded variation. Among other results, we prove that X∗ is a G. T.-space if and only if A lies inside the range of some X∗∗-valued measure with bounded variation whenever XA is isomorphic to a Hilbert space.
Reinforcement Learning with Bounded Information Loss
Peters, Jan; Mülling, Katharina; Seldin, Yevgeny; Altun, Yasemin
2011-03-01
Policy search is a successful approach to reinforcement learning. However, policy improvements often result in the loss of information. Hence, it has been marred by premature convergence and implausible solutions. As first suggested in the context of covariant or natural policy gradients, many of these problems may be addressed by constraining the information loss. In this paper, we continue this path of reasoning and suggest two reinforcement learning methods, i.e., a model-based and a model free algorithm that bound the loss in relative entropy while maximizing their return. The resulting methods differ significantly from previous policy gradient approaches and yields an exact update step. It works well on typical reinforcement learning benchmark problems as well as novel evaluations in robotics. We also show a Bayesian bound motivation of this new approach [8].
Empirical processes with bounded \\psi_1 diameter
Mendelson, Shahar
2010-01-01
We study the empirical process indexed by F^2=\\{f^2 : f \\in F\\}, where F is a class of mean-zero functions on a probability space. We present a sharp bound on the supremum of that process which depends on the \\psi_1 diameter of the class F (rather than on the \\psi_2 one) and on the complexity parameter \\gamma_2(F,\\psi_2). In addition, we present optimal bounds on the random diameters \\sup_{f \\in F} \\max_{|I|=m} (\\sum_{i \\in I} f^2(X_i))^{1/2} using the same parameters. As applications, we extend several well known results in Asymptotic Geometric Analysis to any isotropic, log-concave ensemble on R^n.
Mutual Information Rate and Bounds for It
Baptista, Murilo S.; Rubinger, Rero M.; Viana, Emilson R.; Sartorelli, José C.; Parlitz, Ulrich; Grebogi, Celso
2012-01-01
The amount of information exchanged per unit of time between two nodes in a dynamical network or between two data sets is a powerful concept for analysing complex systems. This quantity, known as the mutual information rate (MIR), is calculated from the mutual information, which is rigorously defined only for random systems. Moreover, the definition of mutual information is based on probabilities of significant events. This work offers a simple alternative way to calculate the MIR in dynamical (deterministic) networks or between two time series (not fully deterministic), and to calculate its upper and lower bounds without having to calculate probabilities, but rather in terms of well known and well defined quantities in dynamical systems. As possible applications of our bounds, we study the relationship between synchronisation and the exchange of information in a system of two coupled maps and in experimental networks of coupled oscillators. PMID:23112809
Dynamics of Nonlinear Waves on Bounded Domains
Maliborski, Maciej
2016-01-01
This thesis is concerned with dynamics of conservative nonlinear waves on bounded domains. In general, there are two scenarios of evolution. Either the solution behaves in an oscillatory, quasiperiodic manner or the nonlinear effects cause the energy to concentrate on smaller scales leading to a turbulent behaviour. Which of these two possibilities occurs depends on a model and the initial conditions. In the quasiperiodic scenario there exist very special time-periodic solutions. They result for a delicate balance between dispersion and nonlinear interaction. The main body of this dissertation is concerned with construction (by means of perturbative and numerical methods) of time-periodic solutions for various nonlinear wave equations on bounded domains. While turbulence is mainly associated with hydrodynamics, recent research in General Relativity has also revealed turbulent phenomena. Numerical studies of a self-gravitating massless scalar field in spherical symmetry gave evidence that anti-de Sitter space ...
Asymptotic Sharpness of Bounds on Hypertrees
Directory of Open Access Journals (Sweden)
Lin Yi
2017-08-01
Full Text Available The hypertree can be defined in many different ways. Katona and Szabó introduced a new, natural definition of hypertrees in uniform hypergraphs and investigated bounds on the number of edges of the hypertrees. They showed that a k-uniform hypertree on n vertices has at most (nk−1$\\left( {\\matrix{n \\cr {k - 1} } } \\right$ edges and they conjectured that the upper bound is asymptotically sharp. Recently, Szabó verified that the conjecture holds by recursively constructing an infinite sequence of k-uniform hypertrees and making complicated analyses for it. In this note we give a short proof of the conjecture by directly constructing a sequence of k-uniform k-hypertrees.
Bounds on bacterial cell growth rates
Landy, Jonathan
2013-01-01
Recent experiments have shown that rod-like bacteria in nutrient-rich media grow in length at an exponential rate. Here, I point out that it is the elongated shape of these bacteria that allows for this behavior. Further, I show that when a bacterium's growth is limited by some nutrient -- taken in by the cell through a diffusion-to-capture process -- its growth is suppressed: In three-dimensional geometries, the length $L$ is bounded by $\\log L \\lesssim t^{1/2}$, while in two dimensions the length is bounded by a power-law form. Fits of experimental growth curves to these predicted, sub-exponential forms could allow for direct measures of quantities relating to cellular metabolic rates.
Mutual information rate and bounds for it.
Directory of Open Access Journals (Sweden)
Murilo S Baptista
Full Text Available The amount of information exchanged per unit of time between two nodes in a dynamical network or between two data sets is a powerful concept for analysing complex systems. This quantity, known as the mutual information rate (MIR, is calculated from the mutual information, which is rigorously defined only for random systems. Moreover, the definition of mutual information is based on probabilities of significant events. This work offers a simple alternative way to calculate the MIR in dynamical (deterministic networks or between two time series (not fully deterministic, and to calculate its upper and lower bounds without having to calculate probabilities, but rather in terms of well known and well defined quantities in dynamical systems. As possible applications of our bounds, we study the relationship between synchronisation and the exchange of information in a system of two coupled maps and in experimental networks of coupled oscillators.
Mutual information rate and bounds for it.
Baptista, Murilo S; Rubinger, Rero M; Viana, Emilson R; Sartorelli, José C; Parlitz, Ulrich; Grebogi, Celso
2012-01-01
The amount of information exchanged per unit of time between two nodes in a dynamical network or between two data sets is a powerful concept for analysing complex systems. This quantity, known as the mutual information rate (MIR), is calculated from the mutual information, which is rigorously defined only for random systems. Moreover, the definition of mutual information is based on probabilities of significant events. This work offers a simple alternative way to calculate the MIR in dynamical (deterministic) networks or between two time series (not fully deterministic), and to calculate its upper and lower bounds without having to calculate probabilities, but rather in terms of well known and well defined quantities in dynamical systems. As possible applications of our bounds, we study the relationship between synchronisation and the exchange of information in a system of two coupled maps and in experimental networks of coupled oscillators.
REE bound DNA in natural plant
Institute of Scientific and Technical Information of China (English)
王玉琦; 江平; 郭繁清; 张智勇; 孙景信; 许雷; 曹国印
1999-01-01
The binding of rare earth elements (REEs) with nucleic acids in the leaves of fern Dicranopteris dichotoma (DD) has been studied by molecular activation analysis (MAA). The REEs bound DNA (REE-DNA) was obtained from the leaves of DD. The CTAB-based procedure was modified for extraction of total DNA. The purity of DNA was examined by UV spectroscopy. The DNA obtained was separated and determined by agarose gel electrophoresis further. Meanwhile, the contents of eight rare earth elements (La, Ce, Nd, Sm, Eu,Tb, Yb and Lu) in REE-DNA were detected by instrumental neutron activation analysis (INAA). The results showed that REE-DNA with higher purity could be extracted from plant using this method. It was also found that REEs were bound firmly with DNA in the leaves of DD. The molecular weight (MW) of REE-DNA band was about 22 kb in agarose gel electrophoresis.
Nemytskii operator on generalized bounded variation space
Directory of Open Access Journals (Sweden)
René Erlín Castillo
2014-06-01
Full Text Available In this paper we show that if the Nemytskii operator maps the (φ, α-bounded variation space into itself and satisfies some Lipschitz condition, then there are two functions g and h belonging to the (φ, α-bounded variation space such that f(t, y = g(ty + h(t for all t ∈ [a, b], y ∈ R. Resumen. En este artículo demostramos que si el operador de Nemytskii lleva el espacio de variación (φ, α-acotada en sí mismo, y satisface cierta condición de Lipschitz, entonces existen dos funciones g y h perteneciendo al espacio de variación (φ, α-acotada tal que f(t, y = g(ty + h(t para todo t ∈ [a, b], y ∈ R.
Compressed sensing performance bounds under Poisson noise
Raginsky, Maxim; Marcia, Roummel F; Willett, Rebecca M
2009-01-01
This paper describes performance bounds for compressed sensing (CS) where the underlying sparse or compressible (sparsely approximable) signal is a vector of nonnegative intensities whose measurements are corrupted by Poisson noise. In this setting, standard CS techniques cannot be applied directly for several reasons. First, the usual signal-independent and/or bounded noise models do not apply to Poisson noise, which is non-additive and signal-dependent. Second, the CS matrices typically considered are not feasible in real optical systems because they do not adhere to important constraints, such as nonnegativity and photon flux preservation. Third, the typical $\\ell_2$--$\\ell_1$ minimization leads to overfitting in the high-intensity regions and oversmoothing in the low-intensity areas. In this paper, we describe how a feasible positivity- and flux-preserving sensing matrix can be constructed, and then analyze the performance of a CS reconstruction approach for Poisson data that minimizes an objective functi...
A Holographic Bound on Cosmic Magnetic Fields
McInnes, Brett
2015-01-01
Magnetic fields large enough to be observable are ubiquitous in astrophysics, even at extremely large length scales. This has led to the suggestion that such fields are seeded at very early (inflationary) times, and subsequently amplified by various processes involving, for example, dynamo effects. Many such mechanisms give rise to extremely large magnetic fields at the end of inflationary reheating, and therefore also during the quark-gluon plasma epoch of the early universe. Such plasmas have a well-known holographic description. We show that holography imposes an upper bound on the intensity of magnetic fields (scaled by the squared temperature) in these circumstances, and that the values expected in some models of cosmic magnetism come close to attaining that bound.
Performance bound for quantum absorption refrigerators
Correa, Luis A.; Palao, José P.; Adesso, Gerardo; Alonso, Daniel
2013-04-01
An implementation of quantum absorption chillers with three qubits has been recently proposed that is ideally able to reach the Carnot performance regime. Here we study the working efficiency of such self-contained refrigerators, adopting a consistent treatment of dissipation effects. We demonstrate that the coefficient of performance at maximum cooling power is upper bounded by 3/4 of the Carnot performance. The result is independent of the details of the system and the equilibrium temperatures of the external baths. We provide design prescriptions that saturate the bound in the limit of a large difference between the operating temperatures. Our study suggests that delocalized dissipation, which must be taken into account for a proper modeling of the machine-baths interaction, is a fundamental source of irreversibility which prevents the refrigerator from approaching the Carnot performance arbitrarily closely in practice. The potential role of quantum correlations in the operation of these machines is also investigated.
Performance bounds for Lambda Policy Iteration
Scherrer, Bruno
2007-01-01
We consider the discrete-time infinite-horizon discounted stationary optimal control problem formalized by Markov Decision Processes. We study Lambda Policy Iteration, a family of algorithms parameterized by lambda, originally introduced by Ioffe and Bertsekas. Lambda Policy Iteration generalizes the standard algorithms Value Iteration and Policy Iteration, and has some connections with TD(Lambda) introduced by Sutton & Barto. We deepen the original theory developped by Ioffe and Bertsekas by providing convergence rate bounds which generalize standard bounds for Value Iteration described for instance by Puterman. We also develop the theory of this algorithm when it is used in an approximate form. Doing so, we extend and unify the separate analyses developped by Munos for Approximate Value Iteration and Approximate Policy Iteration.
Preservation under Substructures modulo Bounded Cores
Sankaran, Abhisekh; Madan, Vivek; Kamath, Pritish; Chakraborty, Supratik
2012-01-01
We investigate a model-theoretic property that generalizes the classical notion of "preservation under substructures". We call this property \\emph{preservation under substructures modulo bounded cores}, and present a syntactic characterization via $\\Sigma_2^0$ sentences for properties of arbitrary structures definable by FO sentences. Towards a sharper characterization, we conjecture that the count of existential quantifiers in the $\\Sigma_2^0$ sentence equals the size of the smallest bounded core. While we do not have a proof of the conjecture yet, we show that it holds for special fragments of FO and also over special classes of structures. We present a (not FO-definable) class of finite structures for which the conjecture fails, but for which the classical {\\L}o\\'s-Tarski preservation theorem holds. As a fallout of our studies, we have obtained combinatorial proofs of the {\\L}o\\'s-Tarski theorem for some of the aforementioned cases.
A holographic bound for D3-brane
Energy Technology Data Exchange (ETDEWEB)
Momeni, Davood; Myrzakul, Aizhan; Myrzakulov, Ratbay [Eurasian National University, Eurasian International Center for Theoretical Physics, Astana (Kazakhstan); Eurasian National University, Department of General Theoretical Physics, Astana (Kazakhstan); Faizal, Mir [University of British Columbia-Okanagan, Irving K. Barber School of Arts and Sciences, Kelowna, BC (Canada); University of Lethbridge, Department of Physics and Astronomy, Lethbridge, AB (Canada); Bahamonde, Sebastian [University College London, Department of Mathematics, London (United Kingdom)
2017-06-15
In this paper, we will regularize the holographic entanglement entropy, holographic complexity and fidelity susceptibility for a configuration of D3-branes. We will also study the regularization of the holographic complexity from the action for a configuration of D3-branes. It will be demonstrated that for a spherical shell of D3-branes the regularized holographic complexity is always greater than or equal to the regularized fidelity susceptibility. Furthermore, we will also demonstrate that the regularized holographic complexity is related to the regularized holographic entanglement entropy for this system. Thus, we will obtain a holographic bound involving regularized holographic complexity, regularized holographic entanglement entropy and regularized fidelity susceptibility of a configuration of D3-brane. We will also discuss a bound for regularized holographic complexity from action, for a D3-brane configuration. (orig.)
Some general bounds for 1-D scattering
Visser, M
1999-01-01
One-dimensional scattering problems are of wide physical interest and are encountered in many diverse applications. In this article I establish some very general bounds for reflection and transmission coefficients for one-dimensional potential scattering. Equivalently, these results may be phrased as general bounds on the Bogolubov coefficients, or statements about the transfer matrix. A similar analysis can be provided for the parametric change of frequency of a harmonic oscillator. A number of specific examples are discussed---in particular I provide a general proof that sharp step function potentials always scatter more effectively than the corresponding smoothed potentials. The analysis also serves to collect together and unify what would otherwise appear to be quite unrelated results.
PSPACE Bounds for Rank-1 Modal Logics
Schröder, Lutz
2007-01-01
For lack of general algorithmic methods that apply to wide classes of logics, establishing a complexity bound for a given modal logic is often a laborious task. The present work is a step towards a general theory of the complexity of modal logics. Our main result is that all rank-1 logics enjoy a shallow model property and thus are, under mild assumptions on the format of their axiomatisation, in PSPACE. This leads to a unified derivation of tight PSPACE-bounds for a number of logics including K, KD, coalition logic, graded modal logic, majority logic, and probabilistic modal logic. Our generic algorithm moreover finds tableau proofs that witness pleasant proof-theoretic properties including a weak subformula property. This generality is made possible by a coalgebraic semantics, which conveniently abstracts from the details of a given model class and thus allows covering a broad range of logics in a uniform way.
Exact BPS bound for noncommutative baby Skyrmions
Energy Technology Data Exchange (ETDEWEB)
Domrin, Andrei, E-mail: domrin@mi.ras.ru [Department of Mathematics and Mechanics, Moscow State University, Leninskie gory, 119992, GSP-2, Moscow (Russian Federation); Lechtenfeld, Olaf, E-mail: lechtenf@itp.uni-hannover.de [Institut für Theoretische Physik and Riemann Center for Geometry and Physics, Leibniz Universität Hannover, Appelstraße 2, 30167 Hannover (Germany); Linares, Román, E-mail: lirr@xanum.uam.mx [Departamento de Física, Universidad Autónoma Metropolitana Iztapalapa, San Rafael Atlixco 186, C.P. 09340, México D.F. (Mexico); Maceda, Marco, E-mail: mmac@xanum.uam.mx [Departamento de Física, Universidad Autónoma Metropolitana Iztapalapa, San Rafael Atlixco 186, C.P. 09340, México D.F. (Mexico)
2013-11-25
The noncommutative baby Skyrme model is a Moyal deformation of the two-dimensional sigma model plus a Skyrme term, with a group-valued or Grassmannian target. Exact abelian solitonic solutions have been identified analytically in this model, with a singular commutative limit. Inside any given Grassmannian, we establish a BPS bound for the energy functional, which is saturated by these baby Skyrmions. This asserts their stability for unit charge, as we also test in second-order perturbation theory.
The lower bound on independence number
Institute of Scientific and Technical Information of China (English)
LI; Yusheng
2002-01-01
［1］Caro, Y., New Results on the Independence Number, Technical Report, Tel_Aviv: Tel_Aviv University, 1979.［2］Wei, V., A lower bound on the stability number of a simple graph, Bell Laboratories Technical Memorandum, 1981, 81_11217_11219.\\}［3］Alon, N., Spencer, J., The Probabilistic Method, New York: Wiley_Interscience, 1992.［4］Ajtai, M., Komls, J., Szemerédi E., A note on Ramsey numbers, J. Combin. Theory, Ser. A, 1980, 29: 354-360.［5］Shearer, J., A note on the independence number of triangle_free graphs, Discrete Math., 1983, 46: 83-87.［6］Kim, J., The Ramsey number R(3,t)has order of magnitude t\\+2／logt, Random Structures Algorithms, 1995, 7: 174-207.［7］Tardos, E., 1997 Fulkerson Prize, Notices of American Math. Soc., 1998, 45(8): 984.［8］Griggs, J., Lower bounds on the independence number in term of the degrees, J. Combin. Theory, Ser. B, 1983, 34: 22-29.［9］Li, Y., Rousseau, C., Fan_complete graph Ramsey numbers, J. Graph Theory, 1996, 23: 413-420.［10］Shearer, J., A note on the independence number of triangle_free graphs, II, J. Combin. Theory, Ser. B, 1991, 53: 300-307.［11］Li, Y., Rousseau, C., On book_complete Ramsey numbers, J. Combin. Theory, Ser. B, 1996, 68: 36-44.［12］Li, Y., Rousseau, C., Zang, W., Asymptotic upper bounds for Ramsey functions, Graphs Combin., 2001, 17: 123-128.［13］Caro, Y., Li, Y., Rousseau, C. et al., Asymptotic bounds for some bipartite graph: complete graph Ramsey numbers, Discrete Math., 2000, 220: 51-56.
Singular integral on bounded strictly pseudoconvex domain
Institute of Scientific and Technical Information of China (English)
GONG Ding-dong
2008-01-01
Kytmanov and Myslivets gave a special Cauchy principal value of the singular integral on the bounded strictly pseudoconvex domain with smooth boundary. By means of this Cauchy integral principal value, the corresponding singular integral and a composition formula are obtained. This composition formula is quite different from usual ones in form. As an application, the corresponding singular integral equation and the system of singular integral equations are discussed as well.
Invariance and stability for bounded uncertain systems.
Peng, T. K. C.
1972-01-01
The positive limit sets of the solutions of a contingent differential equation are shown to possess an invariance property. In this connection the 'invariance principle' in the theory of Lyapunov stability is extended to systems with unknown, bounded, time-varying parameters, and thus to a large and important class of nonautonomous systems. Asymptotic stability criteria are obtained and applied to guaranteed cost control problems.
Lower bounds on the Calabi functional
Donaldson, S. K.
2005-01-01
The main result of this paper shows that "test configurations" give new lower bounds on the $L^{2}$ norm of the scalar curvature on a Kahler manifold. This is closely analogous to the analysis of the Yang-Mills functional over Riemann surfaces by Atiyah and Bott. The proof uses asymptotic approximation by finite-dimensional problems: the essential ingredient being the Tian-Zelditch-Lu expansion of the "density of states" function.
Nonminimal global monopoles and bound orbits
Nucamendi, U; Sudarsky, D; Nucamendi, Ulises; Salgado, Marcelo; Sudarsky, Daniel
2000-01-01
We perform a numerical analysis of the gravitational field of a global monopole coupled nonminimally to gravity, and find that, for some given nonminimal couplings (in constrast with the minimal coupling case), there is an attractive region where bound orbits exist. We exhibit the behavior of the frequency shifts that would be associated with `rotation curves' of stars in circular orbits in the spacetimes of such global monopoles.
Upper and lower bounds on quantum codes
Smith, Graeme Stewart Baird
This thesis provides bounds on the performance of quantum error correcting codes when used for quantum communication and quantum key distribution. The first two chapters provide a bare-bones introduction to classical and quantum error correcting codes, respectively. The next four chapters present achievable rates for quantum codes in various scenarios. The final chapter is dedicated to an upper bound on the quantum channel capacity. Chapter 3 studies coding for adversarial noise using quantum list codes, showing there exist quantum codes with high rates and short lists. These can be used, together with a very short secret key, to communicate with high fidelity at noise levels for which perfect fidelity is, impossible. Chapter 4 explores the performance of a family of degenerate codes when used to communicate over Pauli channels, showing they can be used to communicate over almost any Pauli channel at rates that are impossible for a nondegenerate code and that exceed those of previously known degenerate codes. By studying the scaling of the optimal block length as a function of the channel's parameters, we develop a heuristic for designing even better codes. Chapter 5 describes an equivalence between a family of noisy preprocessing protocols for quantum key distribution and entanglement distillation protocols whose target state belongs to a class of private states called "twisted states." In Chapter 6, the codes of Chapter 4 are combined with the protocols of Chapter 5 to provide higher key rates for one-way quantum key distribution than were previously thought possible. Finally, Chapter 7 presents a new upper bound on the quantum channel capacity that is both additive and convex, and which can be interpreted as the capacity of the channel for communication given access to side channels from a class of zero capacity "cloning" channels. This "clone assisted capacity" is equal to the unassisted capacity for channels that are degradable, which we use to find new upper
Sublinear Bounds for Randomized Leader Election
Kutten, Shay; Pandurangan, Gopal; Peleg, David; Robinson, Peter; Trehan, Amitabh
2012-01-01
This paper concerns {\\em randomized} leader election in synchronous distributed networks. A distributed leader election algorithm is presented for complete $n$-node networks that runs in O(1) rounds and (with high probability) uses only $O(\\sqrt{n}\\log^{3/2} n)$ messages to elect a unique leader (with high probability). When considering the "explicit" variant of leader election where eventually every node knows the identity of the leader, our algorithm yields the asymptotically optimal bounds...
A bound particle coupled to two thermostats
Fogedby, Hans C.; Imparato, Alberto
2011-05-01
We consider a harmonically bound Brownian particle coupled to two distinct heat reservoirs at different temperatures. We show that the presence of a harmonic trap does not change the large deviation function from the case of a free Brownian particle discussed by Derrida and Brunet and Visco. Likewise, the Gallavotti-Cohen fluctuation theorem related to the entropy production at the heat sources remains in force. We support the analytical results with numerical simulations.
Tight Bounds for Distributed Functional Monitoring
Woodruff, David P
2011-01-01
We resolve several fundamental questions in the area of distributed functional monitoring, initiated by Cormode, Muthukrishnan, and Yi (SODA, 2008). In this model there are $k$ sites each tracking their input and communicating with a central coordinator that continuously maintain an approximate output to a function $f$ computed over the union of the inputs. The goal is to minimize the communication. We show the randomized communication complexity of estimating the number of distinct elements up to a $1+\\eps$ factor is $\\Omega(k/\\eps^2)$, improving the previous $\\Omega(k + 1/\\eps^2)$ bound and matching known upper bounds. For the $p$-th frequency moment $F_p$, $p > 1$, we improve the previous $\\Omega(k + 1/\\eps^2)$ communication bound to $\\tilde{\\Omega}(k^{p-1}/\\eps^2)$. We obtain similar improvements for heavy hitters, empirical entropy, and other problems. We also show that we can estimate $F_p$, for any $p > 1$, using $\\tilde{O}(k^{p-1}\\poly(\\eps^{-1}))$ communication. This drastically improves upon the pre...
Bounds on hadronic axions from stellar evolution
Raffelt, Georg G.; Dearborn, David S. P.
1987-10-01
We consider in detail the effect of the emission of ``hadronic'' invisible axions (which do not couple to electrons) from the interior of stars on stellar evolution. To this end we calculate plasma emission rates for axions due to the Primakoff process for the full range of conditions encountered in a giant star. Much attention is paid to plasma, degeneracy, and screening effects. We reconsider the solar bound by evolving a 1.0 Msolar star to solar age and lowering the presolar helium abundance so as to obtain the correct present-day luminosity of the Sun. The previous bound on the axion-photon coupling of G9cluster M67 and with the value 1.3×108 yr derived from the number of such stars in the old galactic disk population. We obtain a conservative limit of G9decay and probably the possibility of measuring the solar hadronic axion flux which, according to our bounds, must be less than 2×10-3 of the solar luminosity. There remains a narrow range of parameters (0.01<~G9<~0.1, ma<~10-4 eV) in which a recently proposed laboratory experiment might still measure axionlike particles.
Hybrid bounds for Dirichlet's L-function
Huxley, M. N.; Watt, N.
2000-11-01
This is a paper about upper bounds for Dirichlet's L-function, L(s, [chi]), on its critical line (s + s¯ = 1). It is to be assumed throughout that, unless otherwise stated, the Dirichlet character, [chi], is periodic modulo a prime, r, and is not the principal character mod r. Our main theorem below shows that, if [epsilon] > 0, thenformula here(where A is an absolute constant), for 0 < [alpha] = (log r)/(log t) [less-than-or-eq, slant] 2/753 [minus sign] [epsilon]. Somewhat weaker bounds are obtained for other cases where 0 < [alpha] [less-than-or-eq, slant] 11/180 [minus sign] [epsilon]. Note that in [13] it was shown that, for 0 < [alpha] [less-than-or-eq, slant] 2/57,formula hereOur main theorem is a corollary of the new bounds we prove for certain exponential sums, S, with a Dirichlet character factor:formula herewhere M2 [less-than-or-eq, slant] 2M and f(x) is a real function whose derivatives satisfy certain conditions restricting their size.
Fingerprint of topological Andreev bound states in phase-dependent heat transport
Sothmann, Björn; Hankiewicz, Ewelina M.
2016-08-01
We demonstrate that phase-dependent heat currents through superconductor-topological insulator Josephson junctions provide a useful tool to probe the existence of topological Andreev bound states, even for multichannel surface states. We predict that in the tunneling regime topological Andreev bound states lead to a minimum of the thermal conductance for a phase difference ϕ =π , in clear contrast to a maximum of the thermal conductance at ϕ =π that occurs for trivial Andreev bound states in superconductor-normal-metal tunnel junctions. This opens up the possibility that phase-dependent heat transport can distinguish between topologically trivial and nontrivial 4 π modes. Furthermore, we propose a superconducting quantum interference device geometry where phase-dependent heat currents can be measured using available experimental technology.
Bounds on neutrino mixing with exotic singlet neutrinos
Indian Academy of Sciences (India)
J K Singhal; Sardar Singh; Ashok K Nagawat; N K Sharma
2002-09-01
We examine the effects of mixing induced non-diagonal light–heavy neutrino weak neutral currents on the amplitude for the process $v_{a}\\overline{v}_{a}→ ZZ$ (with $a = e$; or ). By imposing constraint that the amplitude should not exceed the perturbative unitarity limit at high energy $(\\sqrt{s}=)$, we obtain bounds on light–heavy neutrino mixing parameter $\\sin^{2}^{v_{a}}_{L}$ where $^{v_{a}}_{L}$ is the mixing angle. In the case of one heavy neutrino (mass $m_{}$) or mass degenerate heavy neutrinos, for $ = 1$ TeV, no bound is obtained for $m_{} < 0:50$ TeV. However, $\\sin^{2}^{v_{a}}_{L}≤ 3:8× 10^{-6}$ for $m_{} = 5$ TeV and $\\sin^{2} ^{v_{a}}_{L}≤ 6.0× 10^{-8}$ for $m_{} = 10$ TeV. For = ∞, no constraint is obtained for $m_{} < 0:99$ TeV and $\\sin^{2} ^{v_{a}}_{L}≤ 3.8× 10^{-2}$ (for $m_{} = 5$ TeV) and $\\sin^{2}^{v_{a}}_{L}≤ 9.6× 10^{-3}$ (for $m_{} = 10$ TeV).
Dependence Uncertainty Bounds for the Expectile of a Portfolio
Directory of Open Access Journals (Sweden)
Edgars Jakobsons
2015-12-01
Full Text Available We study upper and lower bounds on the expectile risk measure of risky portfolios when the joint distribution of the risky components is not fully specified. First, we summarize methods for obtaining bounds when only the marginal distributions of the components are known, but not their interdependence (unconstrained bounds. In particular, we provide the best-possible upper bound and the best-possible lower bound (under some conditions, as well as numerical procedures to compute them. We also derive simple analytic bounds that appear adequate in various situations of interest. Second, we study bounds when some information on interdependence is available (constrained bounds. When the variance of the portfolio is known, a simple-to-compute upper bound is provided, and we illustrate that it may significantly improve the unconstrained upper bound. We also show that the unconstrained lower bound cannot be readily improved using variance information. Next, we derive improved bounds when the bivariate distributions of each of the risky components and a risk factor are known. When the factor induces a positive dependence among the components, it is typically possible to improve the unconstrained lower bound. Finally, the unconstrained dependence uncertainty spreads of expected shortfall, value-at-risk and the expectile are compared.
Valenzuela, Sergio O; Saitoh, Eiji; Kimura, Takashi
2012-01-01
In a new branch of physics and technology called spin-electronics or spintronics, the flow of electrical charge (usual current) as well as the flow of electron spin, the so-called 'spin current', are manipulated and controlled together. This book provides an introduction and guide to the new physics and application of spin current.
Search for $\\eta$'(958)-nucleus bound states by (p,d) reaction at GSI and FAIR
Fujioka, H; Benlliure, J; Brinkmann, K -T; Friedrich, S; Geissel, H; Gellanki, J; Guo, C; Gutz, E; Haettner, E; Harakeh, M N; Hayano, R S; Higashi, Y; Hirenzaki, S; Hornung, C; Igarashi, Y; Ikeno, N; Itahashi, K; Iwasaki, M; Jido, D; Kalantar-Nayestanaki, N; Kanungo, R; Knoebel, R; Kurz, N; Metag, V; Mukha, I; Nagae, T; Nagahiro, H; Nanova, M; Nishi, T; Ong, H J; Pietri, S; Prochazka, A; Rappold, C; Reiter, M P; Rodríguez-Sánchez, J L; Scheidenberger, C; Simon, H; Sitar, B; Strmen, P; Sun, B; Suzuki, K; Szarka, I; Takechi, M; Tanaka, Y K; Tanihata, I; Terashima, S; Watanabe, Y N; Weick, H; Widmann, E; Winfield, J S; Xu, X; Yamakami, H; Zhao, J
2015-01-01
The mass of the {\\eta}' meson is theoretically expected to be reduced at finite density, which indicates the existence of {\\eta}'-nucleus bound states. To investigate these states, we perform missing-mass spectroscopy for the (p, d) reaction near the {\\eta}' production threshold. The overview of the experimental situation is given and the current status is discussed.
Mixed matrix hollow fiber membranes for removal of protein-bound toxins from human plasma
Tijink, M.S.L.; Wester, M.; Glorieux, G.; Gerritsen, K; Sun, J.; Swart, P.C.; Borneman, Z.; Wessling, M.; Vanholder, R.; Joles, J.A.; Stamatialis, D.
2013-01-01
In end stage renal disease (ESRD) waste solutes accumulate in body fluid. Removal of protein bound solutes using conventional renal replacement therapies is currently very poor while their accumulation is associated with adverse outcomes in ESRD. Here we investigate the application of a hollow fiber
Universality and scaling phenomenology of small-scale turbulence in wall-bounded flows
Wei, L.; Elsinga, G.E.; Brethouwer, G.; Schlatter, P.; Johansson, A.V.
2014-01-01
The Reynolds number scaling of flow topology in the eigenframe of the strain-rate tensor is investigated for wall-bounded flows, which is motivated by earlier works showing that such topologies appear to be qualitatively universal across turbulent flows. The databases used in the current study are
Multiplexed Electrochemistry of DNA-bound Metalloproteins
Pheeney, Catrina G.; Arnold, Anna R.; Grodick, Michael A.; Barton, Jacqueline K.
2013-01-01
Here we describe a multiplexed electrochemical characterization of DNA-bound proteins containing [4Fe-4S] clusters. DNA-modified electrodes have become an essential tool for the characterization of the redox chemistry of DNA repair proteins containing redox cofactors, and multiplexing offers a means to probe different complex samples and substrates in parallel to elucidate this chemistry. Multiplexed analysis of EndonucleaseIII (EndoIII), a DNA repair protein containing a [4Fe-4S] cluster known to be accessible via DNA-mediated charge transport, shows subtle differences in the electrochemical behavior as a function of DNA morphology. The peak splitting, signal broadness, sensitivity to π-stack perturbations, and kinetics were all characterized for the DNA-bound reduction of EndoIII on both closely and loosely packed DNA films. DNA-bound EndoIII is seen to have two different electron transfer pathways for reduction, either through the DNA base stack or through direct surface reduction; closely packed DNA films, where the protein has limited surface accessibility, produce electrochemical signals reflecting electron transfer that is DNA-mediated. Multiplexing furthermore permits the comparison of the electrochemistry of EndoIII mutants, including a new family of mutations altering the electrostatics surrounding the [4Fe-4S] cluster. While little change in the midpoint potential was found for this family of mutants, significant variations in the efficiency of DNA-mediated electron transfer were apparent. Based on the stability of these proteins, examined by circular dichroism, we propose that the electron transfer pathway can be perturbed not only by the removal of aromatic residues but also through changes in solvation near the cluster. PMID:23899026
Ionically Bound Peroxidase from Peach Fruit
Directory of Open Access Journals (Sweden)
Neves Valdir Augusto
2002-01-01
Full Text Available Soluble, ionically bound peroxidase (POD and polyphenoloxidase (PPO were extracted from the pulp of peach fruit during ripening at 20°C. Ionically bound form was purified 6.1-fold by DEAE-cellulose and Sephadex G-100 chromatography. The purified enzyme showed only one peak of activity on Sephadex G-100 and PAGE revealed that the enzyme was purified by the procedures adopted. The purified enzyme showed a molecular weight of 29000 Da, maximum activity at pH 5.0 and at 40ºC. The calculated apparent activation energy (Ea for the reaction was10.04 kcal/mol. The enzyme was heat-labile in the temperature range of 60 to 75ºC with a fast inactivation at 75ºC. Measurement of residual activity showed a stabilizing effect of sucrose at various temperature/sugar concentrations (0, 10, 20 %, w/w, with an activation energy (Ea for inactivation increasing with sucrose concentration from 0 to 20% (w/w. The Km and Vmax values were 9.35 and 15.38 mM for 0-dianisidine and H2O2, respectively. The bound enzyme was inhibited competitively by ferulic, caffeic and protocatechuic acids with different values of Ki,. L-cysteine, p-coumaric and indolacetic acid and Fe++ also inhibited the enzyme but at a lower grade. N-ethylmaleimide and p-CMB were not effective to inhibit the enzyme demonstrating the non-essentiality of SH groups.
Spectral conditions for entanglement witnesses versus bound entanglement
Chruściński, Dariusz; Kossakowski, Andrzej; Sarbicki, Gniewomir
2009-10-01
It is shown that entanglement witnesses constructed via the family of spectral conditions are decomposable, i.e., cannot be used to detect bound entanglement. It supports several observations that bound entanglement reveals highly nonspectral features.
Spectral conditions for entanglement witnesses vs. bound entanglement
Chruscinski, Dariusz; Sarbicki, Gniewomir
2009-01-01
It is shown that entanglement witnesses constructed via the family of spectral conditions are decomposable, i.e. cannot be used to detect bound entanglement. It supports several observations that bound entanglement reveals highly non-spectral features.
Persistence of noncompact normally hyperbolic invariant manifolds in bounded geometry
Eldering, Jaap
2012-01-01
We prove a persistence result for noncompact normally hyperbolic invariant manifolds in Riemannian manifolds of bounded geometry. The bounded geometry of the ambient manifold is a crucial assumption in order to control the uniformity of all estimates throughout the proof.
Is there an quasi-bound state?
Wilkin, C; Chiladze, D; Dymov, S; Hanhart, C; Hartmann, M; Hejny, V; Kacharava, A K; Keshelashvili, I; Khoukaz, A; Maeda, Y; Mersmann, T; Mielke, M; Mikirtychiants, S; Papenbrock, M; Rathmann, F; Rausmann, T; Schleichert, R; Ströher, H; Täschner, A; Valdau, Yu; Wronska, A
2007-01-01
The observed variation of the total cross section for the dp -> 3He eta reaction near threshold means that the magnitude of the s--wave amplitude falls very rapidly with the eta centre--of--mass momentum. It is shown here that recent measurements of the momentum dependence of the angular distribution imply a strong variation also in the phase of this amplitude. Such a behaviour is that expected from a quasi--bound or virtual eta-3He state. The interpretation can be investigated further through measurements of the deuteron or proton analysing powers and/or spin--correlations.
BOUND PERIODICAL HOLDINGS BATTELLE - NORTHWEST LIBRARY
Energy Technology Data Exchange (ETDEWEB)
None
1967-05-01
This report lists the bound periodicals in the Technical Library at the Pacific Northwest Laboratory, operated by Battelle Memorial Institute. It was prepared from a computer program and is arranged in two parts. Part one is an alphabetical list of journals by title; part two is an arrangement of the journals by subject. The list headings are self-explanatory, with the exception of the title code, which is necessary in the machine processing. The listing is complete through June, 1966 and updates an earlier publication issued in March, 1965.
Mass bounds on a very light neutralino
Energy Technology Data Exchange (ETDEWEB)
Dreiner, Herbi K. [Bethe Center for Theoretical Physics and Physikalisches Institut der Universitaet Bonn, Bonn (Germany); Heinemeyer, Sven [Instituto de Fisica de Cantabria (CSIC-UC), Santander (Spain); Kittel, Olaf [Universidad de Granada, Departamento de Fisica Teorica y del Cosmos and CAFPE, Granada (Spain); Langenfeld, Ulrich [DESY Zeuthen, Zeuthen (Germany); Weber, Arne M. [Max-Planck-Institut fuer Physik (Werner-Heisenberg-Institut), Munich (Germany); Weiglein, Georg [University of Durham, IPPP, Durham (United Kingdom)
2009-08-15
Within the Minimal Supersymmetric Standard Model (MSSM) we systematically investigate the bounds on the mass of the lightest neutralino. We allow for non-universal gaugino masses and thus even consider massless neutralinos, while assuming in general that R-parity is conserved. Our main focus is on laboratory constraints. We consider collider data, precision observables, and also rare meson decays to very light neutralinos. We then discuss the astrophysical and cosmological implications. We find that a massless neutralino is allowed by all existing experimental data and astrophysical and cosmological observations. (orig.)
Betweenness Centrality : Algorithms and Lower Bounds
Kintali, Shiva
2008-01-01
One of the most fundamental problems in large scale network analysis is to determine the importance of a particular node in a network. Betweenness centrality is the most widely used metric to measure the importance of a node in a network. In this paper, we present a randomized parallel algorithm, lower bounds and an algebraic method for computing betweenness centrality of all nodes in a network. We prove that any path comparison based algorithm cannot compute betweenness of all nodes in less than O(nm) time.
Total-variation regularization with bound constraints
Energy Technology Data Exchange (ETDEWEB)
Chartrand, Rick [Los Alamos National Laboratory; Wohlberg, Brendt [Los Alamos National Laboratory
2009-01-01
We present a new algorithm for bound-constrained total-variation (TV) regularization that in comparison with its predecessors is simple, fast, and flexible. We use a splitting approach to decouple TV minimization from enforcing the constraints. Consequently, existing TV solvers can be employed with minimal alteration. This also makes the approach straightforward to generalize to any situation where TV can be applied. We consider deblurring of images with Gaussian or salt-and-pepper noise, as well as Abel inversion of radiographs with Poisson noise. We incorporate previous iterative reweighting algorithms to solve the TV portion.
Bound Alternative Direction Optimization for Image Deblurring
Directory of Open Access Journals (Sweden)
Xiangrong Zeng
2014-01-01
the ℓp regularizer by a novel majorizer and then, based on a variable splitting, to reformulate the bound unconstrained problem into a constrained one, which is then addressed via an augmented Lagrangian method. The proposed algorithm actually combines the reweighted ℓ1 minimization method and the alternating direction method of multiples (ADMM such that it succeeds in extending the application of ADMM to ℓp minimization problems. The conducted experimental studies demonstrate the superiority of the proposed algorithm for the synthesis ℓp minimization over the state-of-the-art algorithms for the synthesis ℓ1 minimization on image deblurring.
Valuation models and Simon's bounded rationality
Directory of Open Access Journals (Sweden)
Alexandra Strommer de Farias Godoi
2009-09-01
Full Text Available This paper aims at reconciling the evidence that sophisticated valuation models are increasingly used by companies in their investment appraisal with the literature of bounded rationality, according to which objective optimization is impracticable in the real world because it would demand an immense level of sophistication of the analytical and computational processes of human beings. We show how normative valuation models should rather be viewed as forms of reality representation, frameworks according to which the real world is perceived, fragmented for a better understanding, and recomposed, providing an orderly method for undertaking a task as complex as the investment decision.
Mass bounds on a very light neutralino
Energy Technology Data Exchange (ETDEWEB)
Dreiner, Herbi K. [Bonn Univ. (Germany). Bethe Center for Theoretical Physis and Physikalisches Institut; Heinemeyer, Sven [Instituto de Fisica de Cantabria (CSIC-UC), Santander (Spain); Kittel, Olaf [Granada Univ. (Spain). Dept. de Fisica Teorica y del Cosmos and CAFPE; Langenfeld, Ulrich [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany); Weber, Arne M. [Max-Planck-Institut fuer Physik, Muenchen (Germany). Werner-Heisenberg-Institut; Weiglein, Georg [Durham Univ. (United Kingdom). IPPP
2008-12-15
Within the Minimal Supersymmetric Standard Model (MSSM) we systematically investigate the bounds on the mass of the lightest neutralino. We allow for non-universal gaugino masses and thus even consider massless neutralinos, while assuming in general that R-parity is conserved. Our main focus are laboratory constraints. We consider collider data, precision observables, and also rare meson decays to very light neutralinos. We then discuss the astrophysical and cosmological implications. We find that a massless neutralino is allowed by all existing experimental data and astrophysical and cosmological observations. (orig.)
Landauer Bound for Analog Computing Systems
Diamantini, M Cristina; Trugenberger, Carlo A
2016-01-01
By establishing a relation between information erasure and continuous phase transitions we generalise the Landauer bound to analog computing systems. The entropy production per degree of freedom during erasure of an analog variable (reset to standard value) is given by the logarithm of the configurational volume measured in units of its minimal quantum. As a consequence every computation has to be carried on with a finite number of bits and infinite precision is forbidden by the fundamental laws of physics, since it would require an infinite amount of energy.
Bounds on entanglement in qudit subsystems
Kendon, Vivien M.; Zyczkowski, Karol; Munro, William J.
2002-01-01
The entanglement in a pure state of N qudits (d-dimensional distinguishable quantum particles) can be characterised by specifying how entangled its subsystems are. A generally mixed subsystem of m qudits is obtained by tracing over the other N-m qudits. We examine the entanglement in the space of mixed states of m qudits. We show that for a typical pure state of N qudits, its subsystems smaller than N/3 qudits will have a positive partial transpose and hence are separable or bound entangled. ...
Novel Bound States in Graphene with Impurities
Gupta, Kumar S
2008-01-01
We obtain a novel bound state spectrum of the low energy excitations near the Fermi points of graphene in the presence of a charge impurity. The effects of possible short range interactions induced by the impurity are modelled by suitable boundary conditions. The spectrum in the subcritical region of the effective Coulomb coupling is labelled by a parameter which characterizes the boundary conditions and determines the inequivalent quantizations of the system. In the supercritical region we obtain a renormalization group flow for the effective Coulomb coupling.
Jackson's Theorem on Bounded Symmetric Domains
Institute of Scientific and Technical Information of China (English)
Ming Zhi WANG; Guang Bin REN
2007-01-01
Polynomial approximation is studied on bounded symmetric domain Ω in C n for holo-morphic function spaces X ,such as Bloch-type spaces,Bergman-type spaces,Hardy spaces,Ω algebra and Lipschitz space.We extend the classical Jackson ’s theorem to several complex variables:E k f,X ) ω (1 /k,f,X ),where E k f,X )is the deviation of the best approximation of f ∈X by polynomials of degree at mostk with respect to the X -metric and ω (1/k,f,X )is the corresponding modulus of continuity.
Mass Bounds on a Very Light Neutralino
Dreiner, H K; Kittel, O; Langenfeld, U; Weber, A M; Weiglein, G
2009-01-01
Within the Minimal Supersymmetric Standard Model (MSSM) we systematically investigate the bounds on the mass of the lightest neutralino. We allow for non-universal gaugino masses and thus even consider massless neutralinos, while assuming in general that R-parity is conserved. Our main focus are laboratory constraints. We consider collider data, precision observables, and also rare meson decays to very light neutralinos. We then discuss the astrophysical and cosmological implications. We find that a massless neutralino is allowed by all existing experimental data and astrophysical and cosmological observations.
Mass bounds on a very light neutralino
Dreiner, Herbi K.; Heinemeyer, Sven; Kittel, Olaf; Langenfeld, Ulrich; Weber, Arne M.; Weiglein, Georg
2009-08-01
Within the Minimal Supersymmetric Standard Model (MSSM) we systematically investigate the bounds on the mass of the lightest neutralino. We allow for non-universal gaugino masses and thus even consider massless neutralinos, while assuming in general that R-parity is conserved. Our main focus is on laboratory constraints. We consider collider data, precision observables, and also rare meson decays to very light neutralinos. We then discuss the astrophysical and cosmological implications. We find that a massless neutralino is allowed by all existing experimental data and astrophysical and cosmological observations.
A Holographic Bound for D3-Brane
Momeni, Davood; Bahamonde, Sebastian; Myrzakul, Aizhan; Myrzakulov, Ratbay
2016-01-01
In this paper, we will calculate the holographic entanglement entropy, holographic complexity, and fidelity susceptibility for a D3-brane. It will be demonstrated that for a D3-brane the holographic complexity is always greater than or equal to than the fidelity susceptibility. Furthermore, we will also demonstrate that the holographic complexity is related to the holographic entanglement entropy for this system. Thus, we will obtain a holographic bound involving holographic complexity, holographic entanglement entropy and fidelity susceptibility of a D3-brane.
Andreev bound states. Some quasiclassical reflections
Energy Technology Data Exchange (ETDEWEB)
Lin, Y., E-mail: yiriolin@illinois.edu; Leggett, A. J. [University of Illinois at Urhana-Champaign, Dept. of Physics (United States)
2014-12-15
We discuss a very simple and essentially exactly solvable model problem which illustrates some nice features of Andreev bound states, namely, the trapping of a single Bogoliubov quasiparticle in a neutral s-wave BCS superfluid by a wide and shallow Zeeman trap. In the quasiclassical limit, the ground state is a doublet with a splitting which is proportional to the exponentially small amplitude for “normal” reflection by the edges of the trap. We comment briefly on a prima facie paradox concerning the continuity equation and conjecture a resolution to it.
Infrared spectroscopy of weakly bound molecular ions
Energy Technology Data Exchange (ETDEWEB)
Yeh, Lisa I-Ching
1988-11-01
The infrared spectra of a series of hydrated hydronium cluster ions and of protonated ethane ion are presented. A tandem mass spectrometer is ideally suited to obtaining the spectra of such weakly bound molecular ions. Traditional absorption spectroscopy is not feasible in these situations, so the techniques described in this thesis make use of some consequence of photon absorption with higher sensitivity than simply attenuation of laser power. That consequence is dissociation. By first mass selecting the parent ion under study and then mass selecting the fragment ion formed from dissociation, the near unit detection efficiency of ion counting methods has been used to full advantage.
Engineering the coupling between Majorana bound states
Shi, Z. C.; Shao, X. Q.; Xia, Y.; Yi, X. X.
2017-09-01
We study the coupling between Majorana bound states (CMBS), which is mediated by a topologically trivial chain in the presence of pairing coupling and long-range coupling. The results show that CMBS can be enhanced by the pairing coupling and long-range coupling of the trivial chain. When driving the trivial chain by periodic driving field, we deduce the analytical expressions of CMBS in the high-frequency limit, and demonstrate that CMBS can be modulated by the frequency and amplitude of driving field. Finally we exhibit the application of tunable CMBS in realizing quantum logic gates.
Landauer bound for analog computing systems
Diamantini, M. Cristina; Gammaitoni, Luca; Trugenberger, Carlo A.
2016-07-01
By establishing a relation between information erasure and continuous phase transitions we generalize the Landauer bound to analog computing systems. The entropy production per degree of freedom during erasure of an analog variable (reset to standard value) is given by the logarithm of the configurational volume measured in units of its minimal quantum. As a consequence, every computation has to be carried on with a finite number of bits and infinite precision is forbidden by the fundamental laws of physics, since it would require an infinite amount of energy.
Informationally complete quantum measurements & entanglement bounds
Flammia, Steven Thomas
2007-12-01
We define a class of measurements which we call pure-state informationally complete (PSI-complete) POVMs. These are measurements which can be used to reconstruct the pure state of a d-dimensional quantum system, but not necessarily a mixed state. We show that 2d measurement outcomes is necessary and sufficient for PSI-completeness. This demonstrates that the measurement complexity (as measured by the number of measurement outcomes) can achieve quadratic improvements when the system is confidently believed to be in a pure state. Next, we consider symmetric informationally complete POVMs (SIC-POVMs). SIC-POVMs are relevant for mixed state quantum tomography, but are not well understood. We prove a theorem related to the conjectured existence of SIC-POVMs showing the uniqueness (up to certain symmetries) of SIC-POVMs of a particular group-covariant type when the dimension of the Hilbert space is a prime number. In the second part of the dissertation, we consider a computational model that has access to only one pure qubit, along with n qubits in the totally mixed state. This model is thought to be capable of performing sonic computational tasks exponentially faster than any known classical algorithm. We show that circuits of this type generally lead to entangled states, but where the entanglement (as measured by the negativity) is bounded by a constant, independent of n, for all bipartite divisions. This suggests that the global nature of entanglement is a more important resource than the magnitude of the entanglement. We then consider multiply constrained bounds on entanglement measures based on convex constraint functions. We outline the general procedure, and then explicitly implement the program for the case of 4 x N quantum systems by bounding the entanglement of formation, the concurrence, and the tangle. Finally, we develop generalized bounds for quantum single-parameter estimation problems for which the coupling to the parameter is described by intrinsic multi
Arsenic-bound excitons in diamond
Barjon, J.; Jomard, F.; Morata, S.
2014-01-01
A set of new excitonic recombinations is observed in arsenic-implanted diamond. It is composed of two groups of emissions at 5.355/5.361 eV and at 5.215/5.220/5.227 eV. They are respectively attributed to the no-phonon and transverse-optical phonon-assisted recombinations of excitons bound to neutral arsenic donors. From the Haynes rule, an ionization energy of 0.41 eV is deduced for arsenic in diamond, which shows that arsenic is a shallower donor than phosphorus (0.6 eV), in agreement with theory.
Derivation of sink strengths in bounded media
Energy Technology Data Exchange (ETDEWEB)
Brailsford, A.D. (Ford Motor Co., Dearborn, MI (USA). Engineering and Research Staff)
1981-11-01
Several reasons for the need to extend the rate theory of point defect recovery processes to bounded media are cited. This paper is concerned with the essential first step, the derivation of the strength of sinks near a free surface. The Effective Medium method is used. Sink strengths so derived are shown to be formally the same as those found in an unbounded system. Image effects associated with the surface are proved to be small when the sink is located more than a few sink radii from the surface.
Nuclear dynamics of K¯ bound states
Mareš, J.; Friedman, E.; Gal, A.
2006-07-01
K¯ nuclear bound states were generated dynamically within a relativistic mean field (RMF) model. Substantial polarization of the core nucleus was found for light nuclei. The behavior of the dynamically calculated width ΓK¯ as function of the K¯ binding energy was studied. A lower limit of ΓK¯ ˜ 35 - 45 MeV for 1s K¯ nuclear states in light nuclei such as 12C was placed on the width expected for deep binding in the range B K¯ ˜ 100 - 200 MeV.
Fermionic bound states in distinct kinklike backgrounds
Energy Technology Data Exchange (ETDEWEB)
Bazeia, D. [Universidade Federal da Paraiba, Departamento de Fisica, Joao Pessoa, Paraiba (Brazil); Mohammadi, A. [Universidade Federal de Campina Grande, Departamento de Fisica, Caixa Postal 10071, Campina Grande, Paraiba (Brazil)
2017-04-15
This work deals with fermions in the background of distinct localized structures in the two-dimensional spacetime. Although the structures have a similar topological character, which is responsible for the appearance of fractionally charged excitations, we want to investigate how the geometric deformations that appear in the localized structures contribute to the change in the physical properties of the fermionic bound states. We investigate the two-kink and compact kinklike backgrounds, and we consider two distinct boson-fermion interactions, one motivated by supersymmetry and the other described by the standard Yukawa coupling. (orig.)
Complexity Considerations, cSAT Lower Bound
Hofman, Radoslaw
2007-01-01
This article discusses completeness of Boolean Algebra as First Order Theory in Goedel's meaning. If Theory is complete then any possible transformation is equivalent to some transformation using axioms, predicates etc. defined for this theory. If formula is to be proved (or disproved) then it has to be reduced to axioms. If every transformation is deducible then also optimal transformation is deducible. If every transformation is exponential then optimal one is too, what allows to define lower bound for discussed problem to be exponential (outside P). Then we show algorithm for NDTM solving the same problem in O(n^c) (so problem is in NP), what proves that P \
Black-hole bombs and photon-mass bounds.
Pani, Paolo; Cardoso, Vitor; Gualtieri, Leonardo; Berti, Emanuele; Ishibashi, Akihiro
2012-09-28
Generic extensions of the standard model predict the existence of ultralight bosonic degrees of freedom. Several ongoing experiments are aimed at detecting these particles or constraining their mass range. Here we show that massive vector fields around rotating black holes can give rise to a strong superradiant instability, which extracts angular momentum from the hole. The observation of supermassive spinning black holes imposes limits on this mechanism. We show that current supermassive black-hole spin estimates provide the tightest upper limits on the mass of the photon (m(v) is black holes could further lower this bound to m(v) black holes in the slow-rotation regime, that we developed up to second order in rotation, and that can be extended to other spacetime metrics and other theories.
Bounding the Probability of Error for High Precision Recognition
Kae, Andrew; Learned-Miller, Erik
2009-01-01
We consider models for which it is important, early in processing, to estimate some variables with high precision, but perhaps at relatively low rates of recall. If some variables can be identified with near certainty, then they can be conditioned upon, allowing further inference to be done efficiently. Specifically, we consider optical character recognition (OCR) systems that can be bootstrapped by identifying a subset of correctly translated document words with very high precision. This "clean set" is subsequently used as document-specific training data. While many current OCR systems produce measures of confidence for the identity of each letter or word, thresholding these confidence values, even at very high values, still produces some errors. We introduce a novel technique for identifying a set of correct words with very high precision. Rather than estimating posterior probabilities, we bound the probability that any given word is incorrect under very general assumptions, using an approximate worst case ...
Baryons as relativistic three-quark bound states
Eichmann, Gernot; Williams, Richard; Alkofer, Reinhard; Fischer, Christian S
2016-01-01
We review the spectrum and electromagnetic properties of baryons described as relativistic three-quark bound states within QCD. The composite nature of baryons results in a rich excitation spectrum, whilst leading to highly non-trivial structural properties explored by the coupling to external (electromagnetic and other) currents. Both present many unsolved problems despite decades of experimental and theoretical research. We discuss the progress in these fields from a theoretical perspective, focusing on nonperturbative QCD as encoded in the functional approach via Dyson-Schwinger and Bethe-Salpeter equations. We give a systematic overview as to how results are obtained in this framework and explain technical connections to lattice QCD. We also discuss the mutual relations to the quark model, which still serves as a reference to distinguish 'expected' from 'unexpected' physics. We confront recent results on the spectrum of non-strange and strange baryons, their form factors and the issues of two-photon proce...
SMT-based Bounded Model Checking with Difference Logic Constraints
Bersani, Marcello M; Morzenti, Angelo; Pradella, Matteo; Rossi, Matteo; Pietro, Pierluigi San
2010-01-01
Traditional Bounded Model Checking (BMC) is based on translating the model checking problem into SAT, the Boolean satisfiability problem. This paper introduces an encoding of Linear Temporal Logic with Past operators (PLTL) into the Quantifier-Free Difference Logic with Uninterpreted Functions (QF-UFIDL). The resulting encoding is a simpler and more concise version of existing SATbased encodings, currently used in BMC. In addition, we present an extension of PLTL augmented with arithmetic relations over integers, which can express unbounded counters; as such, the extended logic is more expressive than PLTL. We introduce suitable restrictions and assumptions that are shown to make the verification problem for the extended logic decidable, and we define an encoding of the new logic into QF-UFIDL. Finally, a performance comparison with the SAT-based approach on purely PLTL examples shows significant improvements in terms of both execution time and memory occupation.
Persistence-Based Branch Misprediction Bounds for WCET Analysis
DEFF Research Database (Denmark)
Puffitsch, Wolfgang
2015-01-01
Branch prediction is an important feature of pipelined processors to achieve high performance. However, it can lead to overly pessimistic worst-case execution time (WCET) bounds when being modeled too conservatively. This paper presents bounds on the number of branch mispredictions for local dyna...... linear programming formulations of the WCET problem. An evaluation on a number of benchmarks shows that with these bounds, dynamic branch prediction does not necessarily lead to higher WCET bounds than static prediction schemes....
Greedy Wavelet Projections are Bounded on BV (Preprint)
2003-10-30
functions of bounded variation on IRd with d ??? 2. Let ????, ?? ??? ??, be a wavelet basis of compactly supported functions normalized in BV, i.e...Wojtaszczyk October 30, 2003 Abstract Let BV = BV(IRd) be the space of functions of bounded variation on IRd with d ≥ 2. Let ψλ, λ ∈ ∆, be a wavelet basis...greedy approximation, functions of bounded variation , thresholding, bounded projections. 1 Introduction The space BV := BV(Ω) of functions of
Bounds for the connective constant of the hexagonal lattice
Energy Technology Data Exchange (ETDEWEB)
Alm, S E; Parviainen, R [Department of Mathematics, Uppsala University, Box 480, 75106 Uppsala (Sweden)
2004-01-23
We give improved bounds for the connective constant of the hexagonal lattice. The lower bound is found by using Kesten's method of irreducible bridges and by determining generating functions for bridges on one-dimensional lattices. The upper bound is obtained as the largest eigenvalue of a certain transfer matrix. Using a relation between the hexagonal and the (3.12{sup 2}) lattices, we also give bounds for the connective constant of the latter lattice.
Asymptotic bound on binary self-orthogonal codes
Institute of Scientific and Technical Information of China (English)
DING Yang
2009-01-01
We present two constructions for binary self-orthogonal codes. It turns out that our constructions yield a constructive bound on binary self-orthogonal codes. In particular, when the in-formation rate R = 1/2, by our constructive lower bound, the relative minimum distance δ≈ 0.0595 (for GV bound, δ≈0.110). Moreover, we have proved that the binary self-orthogonal codes asymptotically achieve the Gilbert-Varshamov bound.
Asymptotic bound on binary self-orthogonal codes
Institute of Scientific and Technical Information of China (English)
无
2009-01-01
We present two constructions for binary self-orthogonal codes. It turns out that our constructions yield a constructive bound on binary self-orthogonal codes. In particular, when the in-formation rate R = 1/2, by our constructive lower bound, the relative minimum distance δ≈ 0.0595 (for GV bound, δ≈ 0.110). Moreover, we have proved that the binary self-orthogonal codes asymptotically achieve the Gilbert-Varshamov bound.
Andrade, Daniel
2012-01-01
We present a new method to propagate lower bounds on conditional probability distributions in conventional Bayesian networks. Our method guarantees to provide outer approximations of the exact lower bounds. A key advantage is that we can use any available algorithms and tools for Bayesian networks in order to represent and infer lower bounds. This new method yields results that are provable exact for trees with binary variables, and results which are competitive to existing approximations in credal networks for all other network structures. Our method is not limited to a specific kind of network structure. Basically, it is also not restricted to a specific kind of inference, but we restrict our analysis to prognostic inference in this article. The computational complexity is superior to that of other existing approaches.
Candidate for laser cooling of a negative ion: observations of bound-bound transitions in La(-).
Walter, C W; Gibson, N D; Matyas, D J; Crocker, C; Dungan, K A; Matola, B R; Rohlén, J
2014-08-08
Despite the tremendous advances in laser cooling of neutral atoms and positive ions, no negatively charged ion has been directly laser cooled. The negative ion of lanthanum, La(-), has been proposed as the best candidate for laser cooling of any atomic anion [ and , Phys. Rev. A 81, 032503 (2010)]. Tunable infrared laser photodetachment spectroscopy is used to measure the bound-state structure of La(-), revealing a spectrum of unprecedented richness with multiple bound-bound electric dipole transitions. The potential laser-cooling transition ((3)F(2)(e)→(3)D(1)(o)) is identified and its excitation energy is measured. The results confirm that La^{-} is a very promising negative ion for laser-cooling applications.
Kobuchi, Shinji; Yano, Kyoka; Ito, Yukako; Sakaeda, Toshiyuki
2016-10-01
Canagliflozin is a novel, orally selective inhibitor of sodium-dependent glucose co-transporter-2 (SGLT2) for the treatment of patients with type 2 diabetes mellitus. In this study, a validated liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for the quantitative analysis of canagliflozin in a lower volume of rat plasma (0.1 mL) was established and applied to a pharmacokinetic study in rats. Following liquid-liquid extraction by tert-butyl methyl ether, chromatographic separation of canagliflozin was performed on a Quicksorb ODS (2.1 mm i.d. × 150 mm, 5 µm size) using acetonitrile-0.1% formic acid (90:10, v/v) as the mobile phase at a flow rate of 0.2 mL/min. The detection was carried out using an API 3200 triple-quadrupole mass spectrometer operating in the positive electrospray ionization mode. Selected ion monitoring transitions of m/z = 462.0 [M + NH4 ](+) → 191.0 for canagliflozin and m/z = 451.2 [M + H](+) → 71.0 for empagliflozin (internal standard) were obtained. The validation of the method was investigated, and it was found to be of sufficient specificity, accuracy and precision. Canagliflozin in rat plasma was stable under the analytical conditions used. This validated method was successfully applied to assess the pharmacokinetics of canagliflozin in rats using 0.1 mL rat plasma. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.
Lower bounds for the minimum distance of algebraic geometry codes
DEFF Research Database (Denmark)
Beelen, Peter
, such as the Goppa bound, the Feng-Rao bound and the Kirfel-Pellikaan bound. I will finish my talk by giving several examples. Especially for two-point codes, the generalized order bound is fairly easy to compute. As an illustration, I will indicate how a lower bound can be obtained for the minimum distance of some......A one-point AG-code is an algebraic geometry code based on a divisor whose support consists of one point. Since the discovery of the Feng-Rao lower bound for the minimum distance, there has been a renewed interest in such codes. This lower bound is also called the order bound. An alternative...... description of these codes in terms of order domains has been found. In my talk I will indicate how one can use the ideas behind the order bound to obtain a lower bound for the minimum distance of any AG-code. After this I will compare this generalized order bound with other known lower bounds...
Upper bounds on the solution of coupled algebraic riccati equation
Directory of Open Access Journals (Sweden)
Czornik Adam
2001-01-01
Full Text Available Upper bounds for eigenvalues of a solution to continuous time coupled algebraic Riccati equation (CCARE and discrete time coupled algebraic Riccati equation (DCARE are developed as special cases of bounds for the unified coupled algebraic Riccati equation (UCARE. They include bounds of the maximal eigenvalues, the sums of the eigenvalues and the trace.
Almost Chebyshev set with respect to bounded subsets
Institute of Scientific and Technical Information of China (English)
李冲; 王兴华
1997-01-01
The uniqueness and existence of restricted Chebyshev center with respect to arbitrary subset are investigated. The concept of almost Chebyshev sets with respect to bounded subsets is introduced. It is proved that each closed subset in a reflexive locally uniformly convex (uniformly convex, respectively) Banach space is an almost Chebyshev subset with respect to compact convex subsets (bounded convex subsets and bounded subsets, respectively).
Bounds in the generalized Weber problem under locational uncertainty
DEFF Research Database (Denmark)
Juel, Henrik
1981-01-01
An existing analysis of the bounds on the Weber problem solution under uncertainty is incorrect. For the generalized problem with arbitrary measures of distance, we give easily computable ranges on the bounds and state the conditions under which the exact values of the bounds can be found...
Bounded Rationality, Retaliation, and the Spread of Urban Violence
Jacobs, Bruce A.; Wright, Richard
2010-01-01
Drawing from in-depth interviews with 52 active street criminals, this article examines the grounded theoretic implications of bounded rationality for retaliatory street violence. The bounds on rationality that this article explores are anger, uncertainty, and time pressure. These bounds create imperfections in the retaliatory decision-making…
Bounds on the capacity of constrained two-dimensional codes
DEFF Research Database (Denmark)
Forchhammer, Søren; Justesen, Jørn
2000-01-01
Bounds on the capacity of constrained two-dimensional (2-D) codes are presented. The bounds of Calkin and Wilf apply to first-order symmetric constraints. The bounds are generalized in a weaker form to higher order and nonsymmetric constraints. Results are given for constraints specified by run...
Improved Space Bounds for Cache-Oblivious Range Reporting
DEFF Research Database (Denmark)
Afshani, Peyman; Zeh, Norbert
2011-01-01
We provide improved bounds on the size of cacheoblivious range reporting data structures that achieve the optimal query bound of O(logB N + K/B) block transfers. Our first main result is an O(N √ logN log logN)-space data structure that achieves this query bound for 3-d dominance reporting and 2-...
The magnetic field generated by an electron bound in angular-momentum eigenstates
Ayuel, K
1999-01-01
The magnetic field generated by an electron bound in a spherically symmetric potential is calculated for eigenstates of the orbital and total angular momentum. General expressions are presented for the current density in such states and the magnetic field is calculated through the vector potential, which is obtained from the current density by direct integration. The method is applied to the hydrogen atom, for which we reproduce and extend known results.
Revisiting the upper bounding process in a safe Branch and Bound algorithm
Goldsztejn, Alexandre; Michel, Claude; Rueher, Michel
2008-01-01
Finding feasible points for which the proof succeeds is a critical issue in safe Branch and Bound algorithms which handle continuous problems. In this paper, we introduce a new strategy to compute very accurate approximations of feasible points. This strategy takes advantage of the Newton method for under-constrained systems of equations and inequalities. More precisely, it exploits the optimal solution of a linear relaxation of the problem to compute efficiently a promising upper bound. First experiments on the Coconuts benchmarks demonstrate that this approach is very effective.
Sasseville, Louis J; Longpré, Jean-Philippe; Wallendorff, Bernadette; Lapointe, Jean-Yves
2014-09-01
The sodium/myo-inositol transporter 2 (SMIT2) is a member of the SLC5A gene family, which is believed to share the five-transmembrane segment inverted repeat of the LeuT structural family. The two-electrode voltage-clamp (TEVC) technique was used to measure the steady-state and the pre-steady-state currents mediated by human SMIT2 after expression in Xenopus laevis oocytes. Phlorizin is first shown to be a poor inhibitor of pre-steady-state currents for depolarizing voltage pulse. From an up to threefold difference between the apparent ON and OFF transferred charges during a voltage pulse, we also show that a fraction of the transient current recorded for very negative potentials is not a true pre-steady-state current coming from the cotransporter conformational changes. We suggest that this transient current comes from a time-dependent leak current that can reach large amplitudes when external Na(+) concentration is reduced. A kinetic model was generated through a simulated annealing algorithm. This algorithm was used to identify the optimal connectivity among 19 different kinetic models and obtain the numerical values of the associated parameters. The proposed 5-state model includes cooperative binding of Na(+) ions, strong apparent asymmetry of the energy barriers, a rate-limiting step that is likely associated with the translocation of the empty transporter, and a turnover rate of 21 s(-1). The proposed model is a proof of concept for a novel approach to kinetic modeling of electrogenic transporters and allows insight into the transport mechanism of members of the LeuT structural family at the millisecond timescale.
Finding Light Spanners in Bounded Pathwidth Graphs
Grigni, Michelangelo
2011-01-01
Given an edge-weighted graph $G$ and $\\epsilon>0$, a $(1+\\epsilon)$-spanner is a spanning subgraph $G'$ whose shortest path distances approximate those of $G$ within a $(1+\\epsilon)$ factor. If $G$ is from certain minor-closed graph families (at least bounded genus graphs and apex graphs), then we know that light spanners exist. That is, we can compute a $(1+\\epsilon)$-spanner $G'$ with total edge weight at most a constant times the weight of a minimum spanning tree. This constant may depend on $\\epsilon$ and the graph family, but not on the particular graph $G$ nor on its edge weighting. For weighted graphs from several minor-closed graph families, the existence of light spanners has been essential in the design of approximation schemes for the metric TSP (the traveling salesman problem) and some similar problems. In this paper we make some progress towards the conjecture that light spanners exist for every minor-closed graph family. In particular, we show that they exist for graphs with bounded pathwidth. W...
Bound and Radiation Fields in Rindler Frame
Hirayama, T
2001-01-01
Energy-momentum tensor of Li\\'enard-Wiechert field is split into bound and emitted parts in Rindler frame, by generalizing the reasoning of Teitelboim used in inertial frame. Our discussion proceeds with the the notion of ``energy'' defined with respect to the Killing vector field attached to the frame. We obtain the ``radiation formula in Rindler frame''(Rindler version of Larmor formula) and it is found that the radiation power is proportional to the square of ``acceleration $\\alpha^\\mu$ of the charge relative to the Rindler frame''. This result makes us split the Li\\'enard-Wiechert field into the part $\\tII$ which is linear in $\\alpha^\\mu$ and the part $\\tI$ which is independent of $\\alpha^\\mu$, and by using them, we split the energy-momentum tensor into two parts. We find that these are properly interpreted as the emitted and bound parts of the tensor in Rindler frame. In our identification of radiation, a charge does not radiate not only in the case where the charge is fixed to the Rindler frame, but als...
Nuclear internal conversion between bound atomic states
Chemin, J. F.; Harston, M. R.; Karpeshin, F. F.; Carreyre, J.; Attallah, F.; Aleonard, M. M.; Scheurer, J. N.; Boggaert, G.; Grandin, J. R.; Trzhaskovskaya, M. B.
2003-01-01
We present experimental and theoretical results for rate of decay of the (3/2)+ isomeric state in 125Te versus the ionic charge state. For charge state larger than 44 the nuclear transition lies below the threshold for emission of a K-shell electron into the continuum with the result that normal internal conversion is energetically forbiden. Rather surprisingly, for the charge 45 and 46 the lifetime of the level was found to have a value close to that in neutral atoms. We present direct evidence that the nuclear transition could still be converted but without the emission of the electron into the continuum, the electron being promoted from the K-shell to an other empty bound state lying close to the continuum. We called this process BIC. The experimental results agree whith theoretical calculations if BIC resonances are taken into account. This leads to a nuclear decay constant that is extremely sensitive to the precise initial state and simple specification of the charge state is no longer appropriate. The contribution to decay of the nucleus of BIC has recently been extended to the situation in which the electron is promoted to an intermediate filled bound state (PFBIC) with an apparent violation of the Pauli principle. Numerical results of the expected dependence of PFBIC on the charge state will be presented for the decay of the 77.351 keV level in 197Au.
Search for a bound K− pp system
Directory of Open Access Journals (Sweden)
Camerini P.
2010-04-01
Full Text Available Data from the K− absorption reaction on 6,7Li, 9Be, 13C and 16O have recently been collected by FINUDA at the DAΦNE φ-factory (Laboratori Nazionali di Frascati-INFN, following an earlier lower statitics run on 12C and some other targets. FINUDA is a high acceptance magnetic spectrometer which performed a wide range of studies by detecting the charged particles and neutrons exiting the targets after the absorption event. In this paper it is discussed about the study of the A(K− , Λp reaction in the context of the search for deeply bound $ar{K}$ - nuclear states. The observation of a bump in the Λp invariant mass distribution is discussed in terms of a possible signature of a deeply bound K− pp kaonic cluster as well as of more conventional physics. An overview of the experimental situation in this ﬁeld will be given.
Bound states -- from QED to QCD
Hoyer, Paul
2014-01-01
These lectures are divided into two parts. In Part 1 I discuss bound state topics at the level of a basic course in field theory: The derivation of the Schr\\"odinger and Dirac equations from the QED Lagrangian, by summing Feynman diagrams and in a Hamiltonian framework. Less well known topics include the equal-time wave function of Positronium in motion and the properties of the Dirac wave function for a linear potential. The presentation emphasizes physical aspects and provides the framework for Part 2, which discusses the derivation of relativistic bound states at Born level in QED and QCD. A central aspect is the maintenance of Poincar\\'e invariance. The transformation of the wave function under boosts is studied in detail in D=1+1 dimensions, and its generalization to D=3+1 is indicated. Solving Gauss' law for $A^0$ with a non-vanishing boundary condition leads to a linear potential for QCD mesons, and an analogous confining potential for baryons.
A bound on the entropy of supergravity?
de Boer, Jan; Messamah, Ilies; Bleeken, Dieter Van den
2009-01-01
We determine, in two independent ways, the number of BPS quantum states arising from supergravity degrees of freedom in a system with fixed total D4D0 charge. First, we count states generated by quantizing the spacetime degrees of freedom of 'entropyless' multicentered solutions consisting of anti-D0-branes bound to a D6-anti-D6 pair. Second, we determine the number of free supergravity excitations of the corresponding AdS_3 geometry with the same total charge. We find that, although these two approaches yield a priori different sets of states, the leading degeneracies in a large charge expansion are equal to each other and that, furthermore, the number of such states is parametrically smaller than that arising from the D4D0 black hole's entropy. This strongly suggests that supergravity alone is not sufficient to capture all degrees of freedom of large supersymmetric black holes. Comparing the free supergravity calculation to that of the D6-anti-D6-D0 system we find that the bound on the free spectrum imposed...
On Aharonov-Casher bound states
Silva, E. O.; Andrade, F. M.; Filgueiras, C.; Belich, H.
2013-04-01
In this work bound states for the Aharonov-Casher problem are considered. According to Hagen's work on the exact equivalence between spin-1/2 Aharonov-Bohm and Aharonov-Casher effects, is known that the ∇ṡ E term cannot be neglected in the Hamiltonian if the spin of particle is considered. This term leads to the existence of a singular potential at the origin. By modeling the problem by boundary conditions at the origin which arises by the self-adjoint extension of the Hamiltonian, we derive for the first time an expression for the bound state energy of the Aharonov-Casher problem. As an application, we consider the Aharonov-Casher plus a two-dimensional harmonic oscillator. We derive the expression for the harmonic oscillator energies and compare it with the expression obtained in the case without singularity. At the end, an approach for determination of the self-adjoint extension parameter is given. In our approach, the parameter is obtained essentially in terms of physics of the problem.