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Sample records for acid leakage hypothesis

  1. The acid-ash hypothesis revisited: a reassessment of the impact of dietary acidity on bone.

    PubMed

    Nicoll, Rachel; McLaren Howard, John

    2014-09-01

    The acid-ash hypothesis states that when there are excess blood protons, bone is eroded to provide alkali to buffer the net acidity and maintain physiologic pH. There is concern that with the typical Western diet, we are permanently in a state of net endogenous acid production, which is gradually reducing bone. While it is clear that a high acid-producing diet generates increased urinary acid and calcium excretion, the effect of diet does not always have the expected results on BMD, fracture risk and markers of bone formation and resorption, suggesting that other factors are influencing the effect of acid/alkali loading on bone. High dietary protein, sodium and phosphorus intake, all of which are necessary for bone formation, were thought to be net acid forming and contribute to low BMD and fracture risk, but appear under certain conditions to be beneficial, with the effect of protein being driven by calcium repletion. Dietary salt can increase short-term markers of bone resorption but may also trigger 1,25(OH)2D synthesis to increase calcium absorption; with low calcium intake, salt intake may be inversely correlated with BMD but with high calcium intake, salt intake was positively correlated with BMD. With respect to the effect of phosphorus, the data are conflicting. Inclusion of an analysis of calcium intake may help to reconcile the contradictory results seen in many of the studies of bone. The acid-ash hypothesis could, therefore, be amended to state that with an acid-producing diet and low calcium intake, bone is eroded to provide alkali to buffer excess protons but where calcium intake is high the acid-producing diet may be protective.

  2. Milk and acid-base balance: proposed hypothesis versus scientific evidence.

    PubMed

    Fenton, Tanis R; Lyon, Andrew W

    2011-10-01

    Recently the lay press has claimed a hypothetical association among dairy product consumption, generation of dietary acid, and harm to human health. This theoretical association is based on the idea that the protein and phosphate in milk and dairy products make them acid-producing foods, which cause our bodies to become acidified, promoting diseases of modern civilization. Some authors have suggested that dairy products are not helpful and perhaps detrimental to bone health because higher osteoporotic fracture incidence is observed in countries with higher dairy product consumption. However, scientific evidence does not support any of these claims. Milk and dairy products neither produce acid upon metabolism nor cause metabolic acidosis, and systemic pH is not influenced by diet. Observations of higher dairy product intake in countries with prevalent osteoporosis do not hold when urban environments are compared, likely due to physical labor in rural locations. Milk and other dairy products continue to be a good source of dietary protein and other nutrients. Key teaching points: Measurement of an acidic pH urine does not reflect metabolic acidosis or an adverse health condition. The modern diet, and dairy product consumption, does not make the body acidic. Alkaline diets alter urine pH but do not change systemic pH. Net acid excretion is not an important influence of calcium metabolism. Milk is not acid producing. Dietary phosphate does not have a negative impact on calcium metabolism, which is contrary to the acid-ash hypothesis.

  3. Increased Serum Hyaluronic Acid and Heparan Sulfate in Dengue Fever: Association with Plasma Leakage and Disease Severity

    PubMed Central

    Tang, Tommy Hing-Cheung; Alonso, Sylvie; Ng, Lisa Fong-Poh; Thein, Tun-Linn; Pang, Vincent Jun-Xiong; Leo, Yee-Sin; Lye, David Chien-Boon; Yeo, Tsin-Wen

    2017-01-01

    Plasma leakage is a major pathogenic mechanism of severe dengue, but the etiology remains unclear. The association between endothelial glycocalyx integrity and vascular permeability in older adults with dengue has not been evaluated. A prospective cohort study of adults with undifferentiated fever screened for dengue by RT-PCR or NS1 antigen testing was performed. Patients were assessed daily while symptomatic and at convalescence. Serum hyaluronic acid (HA), heparan sulfate (HS) and selected cytokines (TNF-α, IL-6, IL-10) were measured on enrollment and convalescence. Patients were diagnosed as dengue fever (DF, n = 30), dengue hemorrhagic fever (DHF, n = 20) and non-dengue (ND) febrile illness (n = 11). Acute HA and HS levels were significantly higher in all dengue patients compared to ND (p = 0.0033 and p = 0.0441 respectively), but not different between DF and DHF (p = 0.3426 and p = 0.9180 respectively). Enrolment HA inversely correlated with serum albumin, protein and platelets in all dengue and DHF (p < 0.05). HA and HS in all dengue patients decreased significantly at convalescence. Serum IL-10 was significantly associated with HA in all dengue patients (p = 0.002). Serum HA and HS levels were increased in adult dengue and HA was associated with markers of disease severity. Endothelial glycocalyx damage may have a role in vascular leakage in dengue. PMID:28393899

  4. A working hypothesis about the cause of Be stars: Episodic outward leakage of low-frequency waves excited by the iron-peak κ-mechanism

    NASA Astrophysics Data System (ADS)

    Shibahashi, Hiromoto

    2014-02-01

    Observations indicate that a circumstellar disk is formed around a Be star while the stellar rotation is below the break-up velocity. I propose a working hypothesis to explain this mystery by taking account of the effect of leaky waves upon angular momentum transfer. In B-type stars near the main sequence, low-frequency nonradial oscillations are excited by the κ-mechanism in the iron bump. They transport angular momentum from the driving zone to the surface. As a consequence, the angular momentum is gradually deposited near the stellar surface. This results in a gradual increase in the ``critical frequency for g-modes'', and g-modes eventually start to leak outward, long before the surface rotation reaches the break-up velocity. This leads to a substantial amount of angular momentum loss from the star, and a circumstellar disk is formed. The oscillations themselves will be soon damped owing to kinetic energy loss. Then the envelope of the star spins down and angular momentum loss stops soon. The star returns to being quiet and remains calm until nonradial oscillations are newly built up by the κ-mechanism to sufficient amplitude and a new episode begins. According to this view, the interval of episodic Be-star activity corresponds to the growth time of the oscillation, and it seems in good agreement with observations.

  5. [The kynurenic acid hypothesis - a new look at etiopathogenesis and treatment of schizophrenia].

    PubMed

    Flis, Marta; Szymona, Kinga; Morylowska-Topolska, Justyna; Urbańska, Anna; Krukow, Paweł; Kandefer-Szerszeń, Martyna; Zdzisińska, Barbara; Urbańska, Ewa M; Karakuła-Juchnowicz, Hanna

    2016-09-29

    Kynurenic acid (KYNA) is a neuroactive metabolite of tryptophan formed in the brain and in the periphery, known to block ionotropic glutamate receptors and α7 nicotinic receptors, and to act as a ligand of G protein-coupled GPR35 receptors and human aryl hydrocarbon (AHR) receptors. KYNA seems to modulate a number of mechanisms involved in the pathogenesis of schizophrenia including dopaminergic transmission in mesolimbic and mesocortical areas or glutamatemediated neurotransmission. The kynurenine hypothesis of schizophrenia links the occurrence of positive and negative symptoms of schizophrenia and cognitive impairments characteristic for the disease with the disturbances of kynurenine pathway function. Available data suggest that antipsychotic drugs may restore balance among kynurenine pathway metabolites, and that co-administration of glycine with antipsychotics may reduce extrapyramidal symptoms in patients suffering from schizophrenia. Central level of KYNA may increase in the course of inflammation, which is consistent with the inflammatory hypothesis of schizophrenia. Alterations of immune response and disturbed functioning of kynurenine pathway may lead to disproportion between neuroprotective and neurotoxic mechanisms in the brain. Currently, intense research efforts are focused on the role of kynurenine pathway metabolites in pathogenesis of schizophrenia, their association with the response to antipsychotic treatment, and search for novel medications modulating the function of kynurenine pathway.

  6. Hypothesis: Could Excessive Fructose Intake and Uric Acid Cause Type 2 Diabetes?

    PubMed Central

    Johnson, Richard J.; Perez-Pozo, Santos E.; Sautin, Yuri Y.; Manitius, Jacek; Sanchez-Lozada, Laura Gabriela; Feig, Daniel I.; Shafiu, Mohamed; Segal, Mark; Glassock, Richard J.; Shimada, Michiko; Roncal, Carlos; Nakagawa, Takahiko

    2009-01-01

    We propose that excessive fructose intake (>50 g/d) may be one of the underlying etiologies of metabolic syndrome and type 2 diabetes. The primary sources of fructose are sugar (sucrose) and high fructose corn syrup. First, fructose intake correlates closely with the rate of diabetes worldwide. Second, unlike other sugars, the ingestion of excessive fructose induces features of metabolic syndrome in both laboratory animals and humans. Third, fructose appears to mediate the metabolic syndrome in part by raising uric acid, and there are now extensive experimental and clinical data supporting uric acid in the pathogenesis of metabolic syndrome. Fourth, environmental and genetic considerations provide a potential explanation of why certain groups might be more susceptible to developing diabetes. Finally, we discuss the counterarguments associated with the hypothesis and a potential explanation for these findings. If diabetes might result from excessive intake of fructose, then simple public health measures could have a major impact on improving the overall health of our populace. PMID:19151107

  7. OF MICE, RATS AND MEN: REVISITING THE QUINOLINIC ACID HYPOTHESIS OF HUNTINGTON’S DISEASE

    PubMed Central

    Schwarcz, R.; Guidetti, P.; Sathyasaikumar, K. V.; Muchowski, P. J.

    2009-01-01

    The neurodegenerative disease Huntington’s Disease (HD) is caused by an expanded polyglutamine (polyQ) tract in the protein huntingtin (htt). Although the gene encoding htt was identified and cloned more than 15 years ago, and in spite of impressive efforts to unravel the mechanism(s) by which mutant htt induces nerve cell death, these studies have so far not led to a good understanding of pathophysiology or an effective therapy. Set against a historical background, we review data supporting the idea that metabolites of the kynurenine pathway (KP) of tryptophan degradation provide a critical link between mutant htt and the pathophysiology of HD. New studies in HD brain and genetic model organisms suggest that the disease may in fact be causally related to early abnormalities in KP metabolism, favoring the formation of two neurotoxic metabolites, 3-hydroxykynurenine and quinolinic acid, over the related neuroprotective agent kynurenic acid. These findings not only link the excitotoxic hypothesis of HD pathology to an impairment of the KP but also define new drug targets and therefore have direct therapeutic implications. Thus, pharmacological normalization of the imbalance in brain KP metabolism may provide clinical benefits, which could be especially effective in the early stages of the disease. PMID:19394403

  8. Role of nicotinic acid and nicotinamide in nicorandil-induced ulcerations: from hypothesis to demonstration.

    PubMed

    Trechot, Philippe; Jouzeau, Jean-Yves; Brouillard, Clotilde; Scala-Bertola, Julien; Petitpain, Nadine; Cuny, Jean-François; Gauchotte, Guillaume; Schmutz, Jean-Luc; Barbaud, Annick

    2015-10-01

    Nicorandil, a nicotinamide ester, was first reported to be involved in the induction of oral ulcers in 1997. Since then, many reports of single or multiple nicorandil-induced ulcerations (NIUs) have been reported. We hypothesised that in the case of high-dosage nicorandil or after an increased dosage of nicorandil, nicotinic acid and nicotinamide (two main metabolites of nicorandil) cannot appropriately merge into the endogenous pool of nicotinamide adenine dinucleotide/phosphate, which leads to abnormal distribution of these metabolites in the body. In recent or maintained trauma, nicotinamide increases blood flow at the edge of the raw area, inducing epithelial proliferation, while nicotinic acid ulcerates this epithelial formation, ultimately flooding the entire scar. We demonstrate, by comparison to a control patient non-exposed to nicorandil, an abnormal amount of nicotinic acid (×38) and nicotinamide (×11) in the ulcerated area in a patient with NIUs. All practitioners, especially geriatricians, dermatologists and surgeons, must be aware of these serious and insidious side effects of nicorandil. It is critical to rapidly reassess the risk-benefit ratio of this drug for any patient, and not only for those with diverticular diseases.

  9. Duodenal acidity may increase the risk of pancreatic cancer in the course of chronic pancreatitis: an etiopathogenetic hypothesis.

    PubMed

    Talamini, Giorgio

    2005-03-10

    Chronic pancreatitis patients have an increased risk of developing pancreatic cancer. The cause of this increase has yet to be fully explained but smoking and inflammation may play an important role. To these, we must now add a new potential risk factor, namely duodenal acidity. Patients with chronic pancreatitis very often present pancreatic exocrine insufficiency combined with a persistently low duodenal pH in the postprandial period. The duodenal mucosa in chronic pancreas patients with pancreatic insufficiency has a normal concentration of s-cells and, therefore, the production of secretin is preserved. Pancreatic ductal cells are largely responsible for the amount of bicarbonate and water secretion in response to secretin stimulation. When gastric acid in the duodenum is not well-balanced by alkaline pancreatic secretions, it may induce a prolonged secretin stimulus which interacts with the pancreatic ductal cells resulting in an increased rate of ductular cell activity and turnover. N-Nitroso compounds from tobacco, identified in human pancreatic juice and known to be important carcinogens, may then act on these active cells, thereby increasing the risk of cancer. Duodenal acidity is probably of particular concern in patients who have undergone a duodenum-preserving pancreatic head resection, since, in this anatomic situation, pancreatic juice transits directly via the jejunal loop, bypassing the duodenum. Patients undergoing a Whipple procedure or side-to-side pancreaticojejunostomy are probably less critically affected because secretions transit, at least in part, via the papilla. If the duodenal acidity hypothesis proves correct, then, in addition to stopping smoking, reduction of duodenal acid load in patients with pancreatic insufficiency may help decrease the risk of pancreatic cancer.

  10. Salvianolic Acid B Ameliorates Lipopolysaccharide-Induced Albumin Leakage from Rat Mesenteric Venules through Src-Regulated Transcelluar Pathway and Paracellular Pathway

    PubMed Central

    Liu, Yu-Ying; Zhang, Yu; He, Ke; Yang, Xiao-Yuan; Hu, Bai-He; Chang, Xin; Wang, Ming-Xia; Wei, Xiao-Hong; Fan, Jing-Yu; Wu, Xin-Min; Han, Jing-Yan

    2015-01-01

    Lipopolysaccharide (LPS) causes microvascular barrier disruption, leading to albumin leakage from microvessels resulting in a range of disastrous sequels. Salvianolic acid B (SalB) is a major water-soluble component derived from Salvia miltiorrhiza. Previous studies showed its potential to attenuate microvascular barrier dysfunction, but the underlying mechanism is not fully understood. The present study was intended to investigate the impact of SalB on endothelial cell barrier in vivo in rat mesenteric venules as well as in vitro in human umbilical vein endothelial cells (HUVECs), aiming at disclosing the mechanism thereof, particularly the role of Src in its action. Male Wistar rats were challenged by infusion of LPS (2 mg/kg/h) through left femoral vein for 90 min. SalB (5 mg/kg/h) was administrated either simultaneously with LPS or 30 min after LPS infusion through the left jugular vein. Vesicles in venular walls were observed by electron microscopy. HUVECs were incubated with LPS with or without SalB. The expression of Zonula occluden-1 (ZO-1), VE-cadherin, caveolin-1 and Src in HUVECs was assessed by Western blot and confocal microscopy, binding of SalB to Src was measured using Surface Plasmon Resonance and BioLayer Interferometry. Treatment with SalB inhibited albumin leakage from rat mesenteric venules and inhibited the increase of vesicle number in venular endothelial cells induced by LPS. In addition, SalB inhibited the degradation of ZO-1, the phosphorylation and redistribution of VE-cadherin, the expression and phosphorylation of caveolin-1, and phosphoirylation of Src in HUVECs exposed to LPS. Furthermore, SalB was found able to bind to Src. This study demonstrates that protection of SalB against microvascular barrier disruption is a process involving both para- and trans-endothelial cell pathway, and highly suggests Src as the key enzyme for SalB to work. PMID:25992563

  11. Salvianolic Acid B Ameliorates Lipopolysaccharide-Induced Albumin Leakage from Rat Mesenteric Venules through Src-Regulated Transcelluar Pathway and Paracellular Pathway.

    PubMed

    Pan, Chun-Shui; Liu, Ying-Hua; Liu, Yu-Ying; Zhang, Yu; He, Ke; Yang, Xiao-Yuan; Hu, Bai-He; Chang, Xin; Wang, Ming-Xia; Wei, Xiao-Hong; Fan, Jing-Yu; Wu, Xin-Min; Han, Jing-Yan

    2015-01-01

    Lipopolysaccharide (LPS) causes microvascular barrier disruption, leading to albumin leakage from microvessels resulting in a range of disastrous sequels. Salvianolic acid B (SalB) is a major water-soluble component derived from Salvia miltiorrhiza. Previous studies showed its potential to attenuate microvascular barrier dysfunction, but the underlying mechanism is not fully understood. The present study was intended to investigate the impact of SalB on endothelial cell barrier in vivo in rat mesenteric venules as well as in vitro in human umbilical vein endothelial cells (HUVECs), aiming at disclosing the mechanism thereof, particularly the role of Src in its action. Male Wistar rats were challenged by infusion of LPS (2 mg/kg/h) through left femoral vein for 90 min. SalB (5 mg/kg/h) was administrated either simultaneously with LPS or 30 min after LPS infusion through the left jugular vein. Vesicles in venular walls were observed by electron microscopy. HUVECs were incubated with LPS with or without SalB. The expression of Zonula occluden-1 (ZO-1), VE-cadherin, caveolin-1 and Src in HUVECs was assessed by Western blot and confocal microscopy, binding of SalB to Src was measured using Surface Plasmon Resonance and BioLayer Interferometry. Treatment with SalB inhibited albumin leakage from rat mesenteric venules and inhibited the increase of vesicle number in venular endothelial cells induced by LPS. In addition, SalB inhibited the degradation of ZO-1, the phosphorylation and redistribution of VE-cadherin, the expression and phosphorylation of caveolin-1, and phosphoirylation of Src in HUVECs exposed to LPS. Furthermore, SalB was found able to bind to Src. This study demonstrates that protection of SalB against microvascular barrier disruption is a process involving both para- and trans-endothelial cell pathway, and highly suggests Src as the key enzyme for SalB to work.

  12. Land-use Leakage

    SciTech Connect

    Calvin, Katherine V.; Edmonds, James A.; Clarke, Leon E.; Bond-Lamberty, Benjamin; Kim, Son H.; Wise, Marshall A.; Thomson, Allison M.; Kyle, G. Page

    2009-12-01

    Leakage occurs whenever actions to mitigate greenhouse gas emissions in one part of the world unleash countervailing forces elsewhere in the world so that reductions in global emissions are less than emissions mitigation in the mitigating region. While many researchers have examined the concept of industrial leakage, land-use policies can also result in leakage. We show that land-use leakage is potentially as large as or larger than industrial leakage. We identify two potential land-use leakage drivers, land-use policies and bioenergy. We distinguish between these two pathways and run numerical experiments for each. We also show that the land-use policy environment exerts a powerful influence on leakage and that under some policy designs leakage can be negative. International “offsets” are a potential mechanism to communicate emissions mitigation beyond the borders of emissions mitigating regions, but in a stabilization regime designed to limit radiative forcing to 3.7 2/m2, this also implies greater emissions mitigation commitments on the part of mitigating regions.

  13. Shroud leakage flow discouragers

    DOEpatents

    Bailey, Jeremy Clyde; Bunker, Ronald Scott

    2002-01-01

    A turbine assembly includes a plurality of rotor blades comprising a root portion, an airfoil having a pressure sidewall and a suction sidewall, and a top portion having a cap. An outer shroud is concentrically disposed about said rotor blades, said shroud in combination with said tip portions defining a clearance gap. At least one circumferential shroud leakage discourager is disposed within the shroud. The leakage discourager(s) increase the flow resistance and thus reduce the flow of hot gas flow leakage for a given pressure differential across the clearance gap to improve overall turbine efficiency.

  14. The Hypothesis that the Genetic Code Originated in Coupled Synthesis of Proteins and the Evolutionary Predecessors of Nucleic Acids in Primitive Cells.

    PubMed

    Francis, Brian R

    2015-02-11

    Although analysis of the genetic code has allowed explanations for its evolution to be proposed, little evidence exists in biochemistry and molecular biology to offer an explanation for the origin of the genetic code. In particular, two features of biology make the origin of the genetic code difficult to understand. First, nucleic acids are highly complicated polymers requiring numerous enzymes for biosynthesis. Secondly, proteins have a simple backbone with a set of 20 different amino acid side chains synthesized by a highly complicated ribosomal process in which mRNA sequences are read in triplets. Apparently, both nucleic acid and protein syntheses have extensive evolutionary histories. Supporting these processes is a complex metabolism and at the hub of metabolism are the carboxylic acid cycles. This paper advances the hypothesis that the earliest predecessor of the nucleic acids was a β-linked polyester made from malic acid, a highly conserved metabolite in the carboxylic acid cycles. In the β-linked polyester, the side chains are carboxylic acid groups capable of forming interstrand double hydrogen bonds. Evolution of the nucleic acids involved changes to the backbone and side chain of poly(β-d-malic acid). Conversion of the side chain carboxylic acid into a carboxamide or a longer side chain bearing a carboxamide group, allowed information polymers to form amide pairs between polyester chains. Aminoacylation of the hydroxyl groups of malic acid and its derivatives with simple amino acids such as glycine and alanine allowed coupling of polyester synthesis and protein synthesis. Use of polypeptides containing glycine and l-alanine for activation of two different monomers with either glycine or l-alanine allowed simple coded autocatalytic synthesis of polyesters and polypeptides and established the first genetic code. A primitive cell capable of supporting electron transport, thioester synthesis, reduction reactions, and synthesis of polyesters and

  15. The Hypothesis that the Genetic Code Originated in Coupled Synthesis of Proteins and the Evolutionary Predecessors of Nucleic Acids in Primitive Cells

    PubMed Central

    Francis, Brian R.

    2015-01-01

    Although analysis of the genetic code has allowed explanations for its evolution to be proposed, little evidence exists in biochemistry and molecular biology to offer an explanation for the origin of the genetic code. In particular, two features of biology make the origin of the genetic code difficult to understand. First, nucleic acids are highly complicated polymers requiring numerous enzymes for biosynthesis. Secondly, proteins have a simple backbone with a set of 20 different amino acid side chains synthesized by a highly complicated ribosomal process in which mRNA sequences are read in triplets. Apparently, both nucleic acid and protein syntheses have extensive evolutionary histories. Supporting these processes is a complex metabolism and at the hub of metabolism are the carboxylic acid cycles. This paper advances the hypothesis that the earliest predecessor of the nucleic acids was a β-linked polyester made from malic acid, a highly conserved metabolite in the carboxylic acid cycles. In the β-linked polyester, the side chains are carboxylic acid groups capable of forming interstrand double hydrogen bonds. Evolution of the nucleic acids involved changes to the backbone and side chain of poly(β-d-malic acid). Conversion of the side chain carboxylic acid into a carboxamide or a longer side chain bearing a carboxamide group, allowed information polymers to form amide pairs between polyester chains. Aminoacylation of the hydroxyl groups of malic acid and its derivatives with simple amino acids such as glycine and alanine allowed coupling of polyester synthesis and protein synthesis. Use of polypeptides containing glycine and l-alanine for activation of two different monomers with either glycine or l-alanine allowed simple coded autocatalytic synthesis of polyesters and polypeptides and established the first genetic code. A primitive cell capable of supporting electron transport, thioester synthesis, reduction reactions, and synthesis of polyesters and

  16. A Comparative Study of the Quality of Apical Seal in Resilon/Epiphany SE Following Intra canal Irrigation With 17% EDTA, 10% Citric Acid, And MTAD as Final Irrigants – A Dye Leakage Study Under Vacuum

    PubMed Central

    Saraswathi, Vidya; Ballal, Nidambur Vasudev; Acharya, Shashi Rashmi; Sampath, J. Sivakumar; Singh, Sandeep

    2017-01-01

    Introduction Adequate apical sealing ability of the root canal filling material is an essential requisite for a successful endodontic therapy. Various endodontic irrigants are used for the removal of smear layer before obturating with a solid core material, thereby, reducing microleakage and improving apical seal. Resilon, a synthetic material was developed as an alternative to replace the conventional gutta-percha (standard root canal filling material) and traditional sealers for the obturation of endodontically treated teeth. Aim To evaluate and compare in-vitro, the post obturation apical seal obtained with Resilon /Epiphany SE (Self Etch) sealer following irrigation with 17% Ethylenediamine Tetra-Acetic Acid (EDTA), 10% citric acid, and MTAD (a mixture of doxycycline, citric acid, and a detergent, Tween 80), as final irrigants in combination with Sodium hypochlorite (NaOCl) using dye leakage under vacuum method. Materials and Methods Fifty five single rooted human maxillary central incisors were subjected to root canal instrumentation. Based on the final irrigation solution, samples were divided into three experimental groups (n=15); (I) 17% EDTA + 1.3% NaOCl, (II) 10% citric acid + 1.3% NaOCl, (III) MTAD + 1.3% NaOCl and two control groups (positive and negative) with 0.9% normal saline as a final irrigant. The samples were obturated with resilon/epiphany SE sealer according to manufacturer instructions and placed in 2% rhodamine B dye solution under vacuum pressure for 30 minutes and allowed to remain in the dye for seven days. All samples were then longitudinally split and examined for dye leakage under stereomicroscope and the data were statistically analysed using one-way ANOVA and post hoc tukey test. Results Statistically significant difference (p=0.001) was observed in the mean apical leakage between the experimental and the control groups. However, there was no significant difference (p>0.05) observed in the mean apical leakage amongst the three

  17. The origins of life -- the 'protein interaction world' hypothesis: protein interactions were the first form of self-reproducing life and nucleic acids evolved later as memory molecules.

    PubMed

    Andras, Peter; Andras, Csaba

    2005-01-01

    The 'protein interaction world' (PIW) hypothesis of the origins of life assumes that life emerged as a self-reproducing and expanding system of protein interactions. In mainstream molecular biology, 'replication' refers to the material copying of molecules such as nucleic acids. However, PIW is conceptualized as an abstract communication system constituted by the interactions between proteins, in which 'replication' happens at the level of self-reproduction of these interactions between proteins. Densely concentrated peptide interaction systems may have reproduced and expanded as 'protocell' vesicles surrounded by lipid bi-layer membranes. Protocells led to the emergence of proto-RNA molecules of greater chemical stability which served as chemically differentiated 'memories' of peptide interaction states, thereby facilitating the reproduction and expansion of protocells. Simplification-driven expansion led to the selection of biotic amino acids and the reduction of the typical RNA alphabet to the four usual bases (A, C, G and U). Dense interactions between RNA molecules led to the emergence of the RNA interaction subsystem of the cell, and to the emergence of 'memories' of RNA interactions in the form of DNA molecules with greater chemical stability. The expansion of DNA molecule interactions led to the dense clustering and encapsulation of DNA molecules within the cell nucleus. RNA molecules therefore serve as memories of protein interactions and DNA molecules are memories of RNA interactions. We believe that the PIW hypothesis is more evolutionarily plausible than the mainstream RNA world hypothesis, and has greater explanatory power.

  18. Predicting recovery from acid rain using the micro-spatial heterogeneity of soil columns downhill the infiltration zone of beech stemflow: introduction of a hypothesis.

    PubMed

    Berger, Torsten W; Muras, Alexander

    Release of stored sulfur may delay the recovery of soil pH from Acid Rain. It is hypothesized that analyzing the micro-spatial heterogeneity of soil columns downhill of a beech stem enables predictions of soil recovery as a function of historic acid loads and time. We demonstrated in a very simplified approach, how these two different factors may be untangled from each other using synthetic data. Thereafter, we evaluated the stated hypothesis based upon chemical soil data with increasing distance from the stem of beech trees. It is predicted that the top soil will recover from acid deposition, as already recorded in the infiltration zone of stemflow near the base of the stem. However, in the between trees areas and especially in deeper soil horizons recovery may be highly delayed.

  19. Quinolinic Acid Responses during Interferon-α-Induced Depressive Symptomatology in Patients with Chronic Hepatitis C Infection - A Novel Aspect for Depression and Inflammatory Hypothesis

    PubMed Central

    Baranyi, Andreas; Meinitzer, Andreas; Breitenecker, Robert J.; Amouzadeh-Ghadikolai, Omid; Stauber, Rudolf; Rothenhäusler, Hans-Bernd

    2015-01-01

    Background The aim of this exploratory study is to gain for the first time a more comprehensive picture of the impact of changes of quinolinic acid concentrations on depressive symptomatology during and after IFN-α therapy. Methods The quinolinic acid concentrations of 35 HCV patients are examined in a prospective survey over the entire period of IFN-α treatment as well as three months later at six different times (baseline, one, three, six and nine months after the beginning of IFN-α treatment, and after the end of treatment). Results During IFN-α treatment Hamilton Depression Rating Scale scores rise significantly. At the same time there is greater activity of indoleamine 2,3-dioxygenase, with a resulting increase in plasma kynurenine concentrations. Compared to baseline values quinolinic acid concentrations increase significantly during therapy, reflecting an increased neurotoxic challenge. In addition, patients with higher scores in the Hamilton Depression Rating Scale at six and nine months after starting therapy show significantly higher levels of quinolinic acid concentration. Conclusions The increase of quinolinic acid during IFN-α therapy might contribute to depressive symptomatology through the neurotoxic challenge caused by quinolinic acid. Subsequently, our exploratory study results support the inflammatory hypothesis of depression. The awareness of relevant risk factors of IFN-α treatment-induced depression is essential to develop preventative treatment strategies. PMID:26368809

  20. Effects of dietary fats on plasma lipids and lipoproteins: an hypothesis for the lipid-lowering effect of unsaturated fatty acids

    PubMed Central

    Spritz, Norton; Mishkel, Maurice A.

    1969-01-01

    Several aspects of the effects of dietary fat on plasma lipids and lipoproteins were investigated in 12 subjects during the long-term feeding of formulas containing 40% of their calories as either saturated or unsaturated fats. The changes in fatty acid composition of plasma lipids, shown previously to occur after prolonged feedings of a dietary fat, required 10-14 days to be complete and were synchronous with the effect of the fat on plasma lipid concentrations. The change in lipid concentration occurred in low but not in high density lipoproteins. The effects on lipid levels of the low density lipoproteins were found to occur with little or no effect on the concentration of the protein moiety of these lipoproteins; as a result, cholesterol- and phospholipid to protein ratios in low density lipoproteins fell during unsaturated fat feeding. The effects of dietary fat on plasma phospholipids were studied in detail: the relative amounts of phosphatidylcholine, phosphatidylethanolamine, sphingomyelin, and lysophosphatidylcholine were unaffected by the type of dietary fat. However, the molecular species of phosphatidylcholine were markedly affected. More than 90% of the fatty acids at the α-position were saturated during both saturated and unsaturated feedings. In contrast, during unsaturated feedings, linoleate at the β-position outnumbered oleate by approximately 4:1, whereas during saturated feedings these two types of fatty acids were present in nearly equal amounts. This paper also presents the following hypothesis for the lipid-lowering effect of unsaturated dietary fat: since unsaturated fatty acids occupy a greater area than saturated acids, they alter the spatial configuration of the lipids into which they are incorporated; as a result, fewer lipid molecules can be accommodated by the apoprotein of the low-density lipoproteins (LDL), and thus the lipid content of the lipoprotein is lowered. The experimental findings of this study, while not proving this

  1. Life Origination Hydrate Hypothesis (LOH-Hypothesis)

    PubMed Central

    Ostrovskii, Victor; Kadyshevich, Elena

    2012-01-01

    The paper develops the Life Origination Hydrate Hypothesis (LOH-hypothesis), according to which living-matter simplest elements (LMSEs, which are N-bases, riboses, nucleosides, nucleotides), DNA- and RNA-like molecules, amino-acids, and proto-cells repeatedly originated on the basis of thermodynamically controlled, natural, and inevitable processes governed by universal physical and chemical laws from CH4, niters, and phosphates under the Earth's surface or seabed within the crystal cavities of the honeycomb methane-hydrate structure at low temperatures; the chemical processes passed slowly through all successive chemical steps in the direction that is determined by a gradual decrease in the Gibbs free energy of reacting systems. The hypothesis formulation method is based on the thermodynamic directedness of natural movement and consists ofan attempt to mentally backtrack on the progression of nature and thus reveal principal milestones alongits route. The changes in Gibbs free energy are estimated for different steps of the living-matter origination process; special attention is paid to the processes of proto-cell formation. Just the occurrence of the gas-hydrate periodic honeycomb matrix filled with LMSEs almost completely in its final state accounts for size limitation in the DNA functional groups and the nonrandom location of N-bases in the DNA chains. The slowness of the low-temperature chemical transformations and their “thermodynamic front” guide the gross process of living matter origination and its successive steps. It is shown that the hypothesis is thermodynamically justified and testable and that many observed natural phenomena count in its favor. PMID:25382120

  2. Impact of food supplementation and methionine on high densities of cotton rats: Support of the amino-acid-quality hypothesis?

    USGS Publications Warehouse

    Webb, R.E.; Leslie, David M.; Lochmiller, R.L.; Masters, R.E.

    2005-01-01

    Considerable research supports the tenet that quantity and quality of food limit vertebrate populations. We evaluated predictions that increased availabilities of food and the essential amino acid methionine were related to population limitation of the hispid cotton rat (Sigmodon hispidus). Effects of supplemental food and methionine on density, survival, and reproductive parameters of wild cotton rats were assessed in north-central Oklahoma in 1998-1999. Twelve enclosed groups of 16 adult cotton rats each (8 male, 8 female) were randomly assigned to either no supplementation (control), supplementation with a mixed ration that had methionine at slightly below maintenance levels (0.20%), or a methionine-enhanced mixed ration (1.20%). In general, densities of cotton rats were twice as high and were sustained longer with dietary supplementation, and methionine-supplemented populations maintained the highest densities. Treatment effects on survival depended on time of year, with higher survival in supplemented enclosures in October and November. Per capita recruitment was highest with methionine-enhanced food. Treatment effects on proportions of overall and female cotton rats in reproductive condition depended on sampling date, but males were most reproductively active with methionine supplementation. Methionine supplementation resulted in an earlier and longer reproductive season. Density-dependent and density-independent factors no doubt interplay to determine population dynamics of cotton rats, but our results suggest that methionine plays a role in the population dynamics of wild cotton rats, apparently by enhancing overall density, recruitment, and reproductive activity of males.

  3. Is the interaction between fatty acids and tryptophan responsible for the efficacy of a ketogenic diet in epilepsy? The new hypothesis of action.

    PubMed

    Maciejak, P; Szyndler, J; Turzyńska, D; Sobolewska, A; Kołosowska, K; Krząścik, P; Płaźnik, A

    2016-01-28

    The effects of a ketogenic diet in controlling seizure activity have been proven in many studies, although its mechanism of action remains elusive in many regards. We hypothesize that the ketogenic diet may exert its antiepileptic effects by influencing tryptophan (TRP) metabolism. The aim of this study was to investigate the influence of octanoic and decanoic fatty acids (FAs), the main components in the MCT diet (medium-chain triglyceride diet, a subtype of the ketogenic diet), on the metabolism of TRP, the activity of the kynurenic pathway and the concentrations of monoamines and amino acids, including branched-chain amino acids (BCAA) and aromatic amino acids (AAA) in rats. The acute effects of FA on the sedation index and hippocampal electrical after-discharge threshold were also assessed. We observed that intragastric administration of FA increased the brain levels of TRP and the central and peripheral concentrations of kynurenic acid (KYNA), as well as caused significant changes in the brain and plasma concentrations of BCAA and AAA. We found that the administration of FA clearly increased the seizure threshold and induced sedation. Furthermore, we have demonstrated that blocking TRP passage into the brain abolished these effects of FA but had no similar effect on the formation of ketone bodies. Given that FAs are major components of a ketogenic diet, it is suggested that the anticonvulsant effects of a ketogenic diet may be at least partly dependent on changes in TRP metabolism. We also propose a more general hypothesis concerning the intracellular mechanism of the ketogenic diet.

  4. Duct Leakage Repeatability Testing

    SciTech Connect

    Walker, Iain; Sherman, Max

    2014-01-01

    Duct leakage often needs to be measured to demonstrate compliance with requirements or to determine energy or Indoor Air Quality (IAQ) impacts. Testing is often done using standards such as ASTM E1554 (ASTM 2013) or California Title 24 (California Energy Commission 2013 & 2013b), but there are several choices of methods available within the accepted standards. Determining which method to use or not use requires an evaluation of those methods in the context of the particular needs. Three factors that are important considerations are the cost of the measurement, the accuracy of the measurement and the repeatability of the measurement. The purpose of this report is to evaluate the repeatability of the three most significant measurement techniques using data from the literature and recently obtained field data. We will also briefly discuss the first two factors. The main question to be answered by this study is to determine if differences in the repeatability of these tests methods is sufficient to indicate that any of these methods is so poor that it should be excluded from consideration as an allowed procedure in codes and standards.

  5. Duct Leakage Repeatability Testing

    SciTech Connect

    Walker, Iain; Sherman, Max

    2014-08-01

    The purpose of this report is to evaluate the repeatability of the three most significant measurement techniques for duct leakage using data from the literature and recently obtained field data. We will also briefly discuss the first two factors. The main question to be answered by this study is to determine if differences in the repeatability of these tests methods is sufficient to indicate that any of these methods is so poor that it should be excluded from consideration as an allowed procedure in codes and standards. The three duct leak measurement methods assessed in this report are the two duct pressurization methods that are commonly used by many practitioners and the DeltaQ technique. These are methods B, C and A, respectively of the ASTM E1554 standard. Although it would be useful to evaluate other duct leak test methods, this study focused on those test methods that are commonly used and are required in various test standards, such as BPI (2010), RESNET (2014), ASHRAE 62.2 (2013), California Title 24 (CEC 2012), DOE Weatherization and many other energy efficiency programs.

  6. Multifamily Envelope Leakage Model

    SciTech Connect

    Faakye, Omari; Griffiths, Dianne

    2015-05-08

    “The cost for blower testing is high, because it is labor intensive, and it may disrupt occupants in multiple units. This high cost and disruption deter program participants, and dissuade them from pursuing energy improvements that would trigger air leakage testing, such as improvements to the building envelope.” This statement found in a 2012 report by Heschong Mahone Group for several California interests emphasizes the importance of reducing the cost and complexity of blower testing in multifamily buildings. Energy efficiency opportunities are being bypassed. The cost of single blower testing is on the order of $300. The cost for guarded blower door testing—the more appropriate test for assessing energy savings opportunities—could easily be six times that, and that’s only if you have the equipment and simultaneous access to multiple apartments. Thus, the proper test is simply not performed. This research seeks to provide an algorithm for predicting the guarded blower door test result based upon a single, total blower door test.

  7. TWO NEW DUCT LEAKAGE TESTS

    SciTech Connect

    ANDREWS,J.W.

    1998-12-01

    Two variations on the tests for duct leakage currently embodied in ASHRAE Standard 152P (Method of Test for Determining the Design and Seasonal Efficiencies of Residential Thermal Distribution Systems) are presented. Procedures are derived for calculating supply and return duct leakage to/from outside using these new variations. Results of these tests are compared with the original ones in Standard 152P on the basis of data collected in three New York State homes.

  8. Application Of The Climafor Baseline To Determine Leakage: TheCase Of Scolel Te.

    SciTech Connect

    De Jong, B.H.J.; Bazan, E. Esquivel; Quechulpa Montalvo, S.

    2007-06-01

    The acceptance of forestry-based project activities tomitigate greenhouse gases emissions has been subjected to a number ofmethodological questions to be answered, of which the most challengingare baseline establishment and identification of and measuring leakage.Here we pose hypotheses for and quantify leakage of the Scolel Te projectin Chiapas, Mexico. In this project small-scale farmers are implementingforestry, agroforestry, and forest conservation activities, with carbonsequestration as one of the goals. The main leakage monitoring domain isdefined as the area owned by the participating farmers or communitiesoutside the area where the specific project activities take place. Thenull-hypothesis (no leakage) is that non-project land owned by the farmeror community will experience the same carbon stock changes as predictedby the regional baseline, specifically developed for the project. Firstwe assessed the most likely causes and sources of leakage that may occurin the project. From this analysis, one type of leakage seems to beimportant, i.e., activity shifting. Second we estimated the leakage of asample of participating farmers and communities. Actual land use was thencompared with expected land use derived from the baseline. The Plan Vivoof each participant, complemented with readily available tools toidentify the main sources and drivers of leakage are used to developsimple leakage assessment procedures, as demonstrated in this paper.Negative leakage was estimated to be negligible in this study.Incorporating these procedures already in the project planning stage willreduce the uncertainties related to the actual carbon mitigationpotential of any forestry project.

  9. The Contrastive Analysis Hypothesis

    ERIC Educational Resources Information Center

    Wardhaugh, Ronald

    1970-01-01

    Discusses the strong contrastive analysis hypothesis, which claims predictive powers for contrastive analysis, and the weak hypothesis, which claims only that contrastive analysis can help account for observed difficulties in second language learning. The strong hypothesis is found untenable, and difficulties with the weak hypothesis are discussed…

  10. Robust characterization of leakage errors

    NASA Astrophysics Data System (ADS)

    Wallman, Joel J.; Barnhill, Marie; Emerson, Joseph

    2016-04-01

    Leakage errors arise when the quantum state leaks out of some subspace of interest, for example, the two-level subspace of a multi-level system defining a computational ‘qubit’, the logical code space of a quantum error-correcting code, or a decoherence-free subspace. Leakage errors pose a distinct challenge to quantum control relative to the more well-studied decoherence errors and can be a limiting factor to achieving fault-tolerant quantum computation. Here we present a scalable and robust randomized benchmarking protocol for quickly estimating the leakage rate due to an arbitrary Markovian noise process on a larger system. We illustrate the reliability of the protocol through numerical simulations.

  11. Air-leakage control manual

    SciTech Connect

    Maloney, J.

    1991-05-01

    This manual is for builders and designers who are interested in building energy-efficient homes. The purpose of the manual is to provide the ``how and why`` of controlling air leakage by means of a system called the ``Simple Caulk and Seal`` (SIMPLE{center_dot}CS) system. This manual provides an overview of the purpose and contents of the manual; It discusses the forces that affect air leakage in homes and the benefits of controlling air leakage. Also discussed are two earlier approaches for controlling air leakage and the problems with these approaches. It describes the SIMPLE-{center_dot}CS system. It outlines the standard components of the building envelope that require sealing and provides guidelines for sealing them. It outlines a step-by-step procedure for analyzing and planning the sealing effort. The procedure includes (1) identifying areas to be sealed, (2) determining the most effective and convenient stage of construction in which to do the sealing, and (3) designating the appropriate crew member or trade to be responsible for the sealing.

  12. Air-Leakage Control Manual.

    SciTech Connect

    Maloney, Jim; Washington State Energy Office; United States. Bonneville Power Administration.

    1991-05-01

    This manual is for builders and designers who are interested in building energy-efficient homes. The purpose of the manual is to provide the how and why'' of controlling air leakage by means of a system called the Simple Caulk and Seal'' (SIMPLE{center dot}CS) system. This manual provides an overview of the purpose and contents of the manual; It discusses the forces that affect air leakage in homes and the benefits of controlling air leakage. Also discussed are two earlier approaches for controlling air leakage and the problems with these approaches. It describes the SIMPLE-{center dot}CS system. It outlines the standard components of the building envelope that require sealing and provides guidelines for sealing them. It outlines a step-by-step procedure for analyzing and planning the sealing effort. The procedure includes (1) identifying areas to be sealed, (2) determining the most effective and convenient stage of construction in which to do the sealing, and (3) designating the appropriate crew member or trade to be responsible for the sealing.

  13. 49 CFR 229.59 - Leakage.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...) Leakage from the main air reservoir and related piping may not exceed an average of 3 pounds per square... shall remain applied at least 5 minutes. (d) Leakage from control air reservoir, related piping,...

  14. Leakage Current Measurements in SOI Devices

    DTIC Science & Technology

    1991-12-01

    Total dose response of both NMOS and PMOS FETs fabrication on SOI substrates were studied. Back channel leakage currents were studied. Two types of...dose of the back channel and front channel of SIMOX and ZMR SOI substrates are reported. Some preliminary reports on the buried oxide leakage current are also provided. Bach channel leakage, SIMOX, ZMR, Total Dose Response .

  15. "Geyser" leakage on fluorescein angiography.

    PubMed

    Levy, Jaime; Fagan, Xavier J; Lifshitz, Tova; Schneck, Marina

    2013-11-22

    An 82-year-old patient with diabetes was followed up due to moderate nonproliferative diabetic retinopathy with macular edema in the right eye. Visual acuity was 6/36. Focal macular laser was conducted (A). Three years later, the patient presented with blurry vision in the right eye. Visual acuity was 3/60. Vitreous hemorrhage was observed (B), and neovascularization of the disc was suspected (C). Fluorescein angiography (D, mid venous phase; E-F, recirculation phase) confirmed neovascularization of the disc and depicted a striking vertical leakage. Panretinal photocoagulation was started. Possible explanations for the "geyser" leakage may be either a partial posterior vitreous detachment allowing the fluorescein to track upwards but not elsewhere or a pocket of syneretic vitreous allowing the fluorescein passage in which to diffuse, much like the passage the blood would have taken.

  16. Duct leakage measurement and analysis

    SciTech Connect

    Swim, W.B.; Griggs, E.I.

    1995-08-01

    Leakage measurements were made on 6-in. (150-mm) and 10-in. (250-mm) round and 14-in. by 6-in. (350-mm by 150-mm) and 22-in. by 8-in. (560-mm by 200-mm) rectangular ducts for both positive and negative internal pressures. The data were found to fit a power law model, with the leakage rate (Q) increasing with a power, n, of static pressure difference ({Delta}p), i.e., Q {proportional_to} ({Delta}p){sup n}. A convenient leakage prediction equation, Q = C ({Delta}p*){sup n}, uses a normalized pressure difference, {Delta}p* = {Delta}p/{Delta}p{sub ref}, with {Delta}p in in. wg (Pa) and a reference pressure difference, {Delta}p{sub ref}, of 1 in. wg (250 Pa). C{sub D}, the recommended design values of C for a repetitive element of a duct system--one duct section and one joint, ranged from 0.01 cfm (0.005 L/s) for a Vanstone flanged joint to 18.5 cfm (8.7 L/s) for an unsealed 22-in. by 8-in (560-mm by 200-mm) duct with a slip-and-drive joint. Most test ducts had C{sub D} values of 6 to 8 cfm (3 to 4 L/s) and had values of n close to 0.58. Joints were found to account for most of the leakage, and thus most of the value of C{sub D}, in unsealed ducts, with seams contributing only 10% to 38% of the total.

  17. Hypothesis analysis methods, hypothesis analysis devices, and articles of manufacture

    SciTech Connect

    Sanfilippo, Antonio P; Cowell, Andrew J; Gregory, Michelle L; Baddeley, Robert L; Paulson, Patrick R; Tratz, Stephen C; Hohimer, Ryan E

    2012-03-20

    Hypothesis analysis methods, hypothesis analysis devices, and articles of manufacture are described according to some aspects. In one aspect, a hypothesis analysis method includes providing a hypothesis, providing an indicator which at least one of supports and refutes the hypothesis, using the indicator, associating evidence with the hypothesis, weighting the association of the evidence with the hypothesis, and using the weighting, providing information regarding the accuracy of the hypothesis.

  18. Factors affecting apical leakage assessment.

    PubMed

    Karagöz-Küçükay, I; Küçükay, S; Bayirli, G

    1993-07-01

    This study was conducted to evaluate the influence of immediate versus delayed immersion time, and passive dye immersion versus centrifuged dye on apical leakage measurements. Eighty-four extracted human teeth with single straight canals were instrumented and divided into four experimental groups of 20 teeth each plus 2 negative and 2 positive controls. Low-temperature injection thermoplasticized gutta-percha and sealer were used to obturate the root canals. In groups A and B the filling materials were allowed to set for 72 h before the teeth were placed in India ink. In groups C and D the teeth were placed in India ink immediately after obturation. Also, in groups B and D the teeth were centrifuged in India ink for 20 min at 3,000 rpm before being immersed in ink. After 72 h in India ink, the teeth were cleared, and the linear extent of ink penetration was measured with a stereomicroscope. Statistical analysis of the data revealed no significant difference in leakage among the experimental groups whether the teeth were immersed in ink immediately after obturation or after setting of the filling materials for 72 h, and whether or not the teeth were centrifuged in ink prior to immersion.

  19. A Temporal Association between Folic Acid Fortification and a Rise in Colorectal Cancer Rates May be Illuminating Important Biological Principles: a Hypothesis

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Nationwide fortification of enriched uncooked cereal grains with folic acid began in the U.S. and Canada in 1996 and 1997, respectively, and became mandatory in 1998. The rationale was to reduce the number of births complicated by neural tube defects. Concurrently, the U.S. and Canada experienced ab...

  20. Zero leakage separable and semipermanent ducting joints

    NASA Technical Reports Server (NTRS)

    Mischel, H. T.

    1973-01-01

    A study program has been conducted to explore new methods of achieving zero leakage, separable and semipermanent, ducting joints for space flight vehicles. The study consisted of a search of literature of existing zero leakage methods, the generation of concepts of new methods of achieving the desired zero leakage criteria and the development of detailed analysis and design of a selected concept. Other techniques of leak detection were explored with a view toward improving this area.

  1. Energy Conservation Through Duct Leakage Reduction

    DTIC Science & Technology

    2004-02-26

    Energy Conservation Through Duct Leakage Reduction February 26, 2004 Rich Glatt – Lindab Inc. Report Documentation Page Form ApprovedOMB No. 0704...4. TITLE AND SUBTITLE Energy Conservation Through Duct Leakage Reduction 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6...Wall – DW that installs like SW - easiest installing DW system on the market – Eliminates the need for costly flanged connections – SMACNA Leakage

  2. Leakage-current properties of encapsulants

    NASA Technical Reports Server (NTRS)

    Wen, L. C.

    1986-01-01

    A theoretical modeling of leakage current in ethylene vinyl acetate (EVA) and polyvinyl butyral (PVB) modules is being developed and is described. The modeling effort derives mathematical relationships for the bulk and surface conductivites of EVA and PVB, the surface conductivities of glass and polymeric films, and the EVA and PVB pottants, all as functions of environmental parameters. Results from the modeling indicate that for glass/EVA, the glass surface controls the interfacial conductivity, although EVA bulk conductivity controls total leakage current. For PVB/glass, the interface conductivity controls leakage currents for relative humidity (RH) less than 40 to 50%, but PVB bulk conductivity controls leakage current above 50% RH.

  3. Microvascular dysfunction with increased vascular leakage response in mice systemically exposed to arsenic.

    PubMed

    Chen, Shih-Chieh; Huang, Shin-Yin; Lu, Chi-Yu; Hsu, Ya-Hung; Wang, Dean-Chuan

    2014-09-01

    The mechanisms underlying cardiovascular disease induced by arsenic exposure are not completely understood. The objectives of this study were to investigate whether arsenic-fed mice have an increased vascular leakage response to vasoactive agents and whether enhanced type-2 protein phosphatase (PP2A) activity is involved in mustard oil-induced leakage. ICR mice were fed water or sodium arsenite (20 mg/kg) for 4 or 8 weeks. The leakage response to vasoactive agents was quantified using the Evans blue (EB) technique or vascular labeling with carbon particles. Increased EB leakage and high density of carbon-labeled microvessels were detected in arsenic-fed mice treated with mustard oil. Histamine induced significantly higher vascular leakage in arsenic-fed mice than in water-fed mice. Pretreatment with the PP2A inhibitor okadaic acid or the neurokinin 1 receptor (NK1R) blocker RP67580 significantly reduced mustard oil-induced vascular leakage in arsenic-fed mice. The protein levels of PP2Ac and NK1R were similar in both groups. PP2A activity was significantly higher in the arsenic-fed mice compared with the control group. These findings indicate that microvessels generally respond to vasoactive agents, and that the increased PP2A activity is involved in mustard oil-induced vascular leakage in arsenic-fed mice. Arsenic may initiate endothelial dysfunction, resulting in vascular leakage in response to vasoactive agents.

  4. 49 CFR 236.735 - Current, leakage.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... Current, leakage. A stray electric current of relatively small value which flows through or across the... 49 Transportation 4 2013-10-01 2013-10-01 false Current, leakage. 236.735 Section 236.735 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD...

  5. 49 CFR 236.735 - Current, leakage.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... Current, leakage. A stray electric current of relatively small value which flows through or across the... 49 Transportation 4 2014-10-01 2014-10-01 false Current, leakage. 236.735 Section 236.735 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD...

  6. 49 CFR 236.735 - Current, leakage.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... Current, leakage. A stray electric current of relatively small value which flows through or across the... 49 Transportation 4 2012-10-01 2012-10-01 false Current, leakage. 236.735 Section 236.735 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD...

  7. 49 CFR 236.735 - Current, leakage.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... Current, leakage. A stray electric current of relatively small value which flows through or across the... 49 Transportation 4 2011-10-01 2011-10-01 false Current, leakage. 236.735 Section 236.735 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD...

  8. 49 CFR 236.735 - Current, leakage.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... Current, leakage. A stray electric current of relatively small value which flows through or across the... 49 Transportation 4 2010-10-01 2010-10-01 false Current, leakage. 236.735 Section 236.735 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD...

  9. 49 CFR 229.59 - Leakage.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... inch per minute for 3 minutes after the pressure has been reduced to 60 percent of the maximum pressure. (b) Brake pipe leakage may not exceed 5 pounds per square inch per minute. (c) With a full service... shall remain applied at least 5 minutes. (d) Leakage from control air reservoir, related piping,...

  10. 16 CFR 1507.5 - Pyrotechnic leakage.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 16 Commercial Practices 2 2011-01-01 2011-01-01 false Pyrotechnic leakage. 1507.5 Section 1507.5 Commercial Practices CONSUMER PRODUCT SAFETY COMMISSION FEDERAL HAZARDOUS SUBSTANCES ACT REGULATIONS FIREWORKS DEVICES § 1507.5 Pyrotechnic leakage. The pyrotechnic chamber in fireworks devices shall be...

  11. 16 CFR 1507.5 - Pyrotechnic leakage.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 16 Commercial Practices 2 2012-01-01 2012-01-01 false Pyrotechnic leakage. 1507.5 Section 1507.5 Commercial Practices CONSUMER PRODUCT SAFETY COMMISSION FEDERAL HAZARDOUS SUBSTANCES ACT REGULATIONS FIREWORKS DEVICES § 1507.5 Pyrotechnic leakage. The pyrotechnic chamber in fireworks devices shall be...

  12. 16 CFR 1507.5 - Pyrotechnic leakage.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 16 Commercial Practices 2 2013-01-01 2013-01-01 false Pyrotechnic leakage. 1507.5 Section 1507.5 Commercial Practices CONSUMER PRODUCT SAFETY COMMISSION FEDERAL HAZARDOUS SUBSTANCES ACT REGULATIONS FIREWORKS DEVICES § 1507.5 Pyrotechnic leakage. The pyrotechnic chamber in fireworks devices shall be...

  13. 16 CFR 1507.5 - Pyrotechnic leakage.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 16 Commercial Practices 2 2010-01-01 2010-01-01 false Pyrotechnic leakage. 1507.5 Section 1507.5 Commercial Practices CONSUMER PRODUCT SAFETY COMMISSION FEDERAL HAZARDOUS SUBSTANCES ACT REGULATIONS FIREWORKS DEVICES § 1507.5 Pyrotechnic leakage. The pyrotechnic chamber in fireworks devices shall be...

  14. 16 CFR 1507.5 - Pyrotechnic leakage.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 16 Commercial Practices 2 2014-01-01 2014-01-01 false Pyrotechnic leakage. 1507.5 Section 1507.5 Commercial Practices CONSUMER PRODUCT SAFETY COMMISSION FEDERAL HAZARDOUS SUBSTANCES ACT REGULATIONS FIREWORKS DEVICES § 1507.5 Pyrotechnic leakage. The pyrotechnic chamber in fireworks devices shall be...

  15. Predicting Envelope Leakage in Attached Dwellings

    SciTech Connect

    Faakye, O.; Arena, L.; Griffiths, D.

    2013-07-01

    The most common method for measuring air leakage is to use a single blower door to pressurize and/or depressurize the test unit. In detached housing, the test unit is the entire home and the single blower door measures air leakage to the outside. In attached housing, this 'single unit', 'total', or 'solo' test method measures both the air leakage between adjacent units through common surfaces as well air leakage to the outside. Measuring and minimizing this total leakage is recommended to avoid indoor air quality issues between units, reduce energy losses to the outside, reduce pressure differentials between units, and control stack effect. However, two significant limitations of the total leakage measurement in attached housing are: for retrofit work, if total leakage is assumed to be all to the outside, the energy benefits of air sealing can be significantly over predicted; for new construction, the total leakage values may result in failing to meet an energy-based house tightness program criterion. The scope of this research is to investigate an approach for developing a viable simplified algorithm that can be used by contractors to assess energy efficiency program qualification and/or compliance based upon solo test results.

  16. Bag Test Measures Leakage From Insulated Pipe

    NASA Technical Reports Server (NTRS)

    Schock, Kent D.; Easter, Barry P.

    1994-01-01

    Test quantifies leakage of gas from pipe even though pipe covered with insulation. Involves use of helium analyzer to measure concentration of helium in impermeable bag around pipe. Test administered after standard soap-solution bubble test indicates presence and general class of leakage.

  17. Radiofrequency radiation leakage from microwave ovens.

    PubMed

    Lahham, Adnan; Sharabati, Afifeh

    2013-12-01

    This work presents data on the amount of radiation leakage from 117 microwave ovens in domestic and restaurant use in the West Bank, Palestine. The study of leakage is based on the measurements of radiation emissions from the oven in real-life conditions by using a frequency selective field strength measuring system. The power density from individual ovens was measured at a distance of 1 m and at the height of centre of door screen. The tested ovens were of different types, models with operating powers between 1000 and 1600 W and ages ranging from 1 month to >20 y, including 16 ovens with unknown ages. The amount of radiation leakage at a distance of 1 m was found to vary from 0.43 to 16.4 μW cm(-2) with an average value equalling 3.64 μW cm(-2). Leakages from all tested microwave ovens except for seven ovens (∼6 % of the total) were below 10 μW cm(-2). The highest radiation leakage from any tested oven was ∼16.4 μW cm(-2), and found in two cases only. In no case did the leakage exceed the limit of 1 mW cm(-2) recommended by the ICNIRP for 2.45-GHz radiofrequency. This study confirms a linear correlation between the amount of leakage and both oven age and operating power, with a stronger dependence of leakage on age.

  18. The gender similarities hypothesis.

    PubMed

    Hyde, Janet Shibley

    2005-09-01

    The differences model, which argues that males and females are vastly different psychologically, dominates the popular media. Here, the author advances a very different view, the gender similarities hypothesis, which holds that males and females are similar on most, but not all, psychological variables. Results from a review of 46 meta-analyses support the gender similarities hypothesis. Gender differences can vary substantially in magnitude at different ages and depend on the context in which measurement occurs. Overinflated claims of gender differences carry substantial costs in areas such as the workplace and relationships.

  19. The Qualitative Similarity Hypothesis

    ERIC Educational Resources Information Center

    Paul, Peter V.; Lee, Chongmin

    2010-01-01

    Evidence is presented for the qualitative similarity hypothesis (QSH) with respect to children and adolescents who are d/Deaf or hard of hearing. The primary focus is on the development of English language and literacy skills, and some information is provided on the acquisition of English as a second language. The QSH is briefly discussed within…

  20. The Gender Similarities Hypothesis

    ERIC Educational Resources Information Center

    Hyde, Janet Shibley

    2005-01-01

    The differences model, which argues that males and females are vastly different psychologically, dominates the popular media. Here, the author advances a very different view, the gender similarities hypothesis, which holds that males and females are similar on most, but not all, psychological variables. Results from a review of 46 meta-analyses…

  1. Surface-active properties of lipophilic antioxidants tyrosol and hydroxytyrosol fatty acid esters: a potential explanation for the nonlinear hypothesis of the antioxidant activity in oil-in-water emulsions.

    PubMed

    Lucas, Ricardo; Comelles, Francisco; Alcántara, David; Maldonado, Olivia S; Curcuroze, Melanie; Parra, Jose L; Morales, Juan C

    2010-07-14

    Our group has recently observed a nonlinear tendency in antioxidant capacity of different hydroxytyrosol fatty acid esters in fish oil-in-water emulsions, where a maximum of antioxidant efficiency appeared for hydroxytyrosol octanoate. These results appear to disagree with the antioxidant polar paradox. Because the physical location of the antioxidants in an oil-water interface has been postulated as an important factor in explaining this behavior, we have prepared a series of tyrosol and hydroxytyrosol fatty acid esters with different chain length and studied their surface-active properties in water, because these physicochemical parameters could be directly related to the preferential placement at the interface. We have found that tyrosol and hydroxytyrosol fatty acid esters are relevant surfactants when the right hydrophilic-lipophilic balance (HLB) is attained and, in some cases, as efficient as emulsifiers commonly used in industry, such as Brij 30 or Tween 20. Moreover, a nonlinear dependency of surfactant effectiveness is observed with the increase in chain length of the lipophilic antioxidants. This tendency seems to fit quite well with the reported antioxidant activity in emulsions, and the best antioxidant of the series (hydroxytyrosol octanoate) is also a very effective surfactant. This potential explanation of the nonlinear hypothesis will help in the rational design of antioxidants used in oil-in-water emulsions.

  2. The interactive brain hypothesis

    PubMed Central

    Di Paolo, Ezequiel; De Jaegher, Hanne

    2012-01-01

    Enactive approaches foreground the role of interpersonal interaction in explanations of social understanding. This motivates, in combination with a recent interest in neuroscientific studies involving actual interactions, the question of how interactive processes relate to neural mechanisms involved in social understanding. We introduce the Interactive Brain Hypothesis (IBH) in order to help map the spectrum of possible relations between social interaction and neural processes. The hypothesis states that interactive experience and skills play enabling roles in both the development and current function of social brain mechanisms, even in cases where social understanding happens in the absence of immediate interaction. We examine the plausibility of this hypothesis against developmental and neurobiological evidence and contrast it with the widespread assumption that mindreading is crucial to all social cognition. We describe the elements of social interaction that bear most directly on this hypothesis and discuss the empirical possibilities open to social neuroscience. We propose that the link between coordination dynamics and social understanding can be best grasped by studying transitions between states of coordination. These transitions form part of the self-organization of interaction processes that characterize the dynamics of social engagement. The patterns and synergies of this self-organization help explain how individuals understand each other. Various possibilities for role-taking emerge during interaction, determining a spectrum of participation. This view contrasts sharply with the observational stance that has guided research in social neuroscience until recently. We also introduce the concept of readiness to interact to describe the practices and dispositions that are summoned in situations of social significance (even if not interactive). This latter idea links interactive factors to more classical observational scenarios. PMID:22701412

  3. Mesoamerican cosmovision: an hypothesis.

    NASA Astrophysics Data System (ADS)

    Franch, J. A.

    In the present conference the author explains a new hypothesis to interpret the cosmogonic vision of the people and the cultures from the Mesoamerican area during the precolumbian period. The hypothesis at issue consists in irregular octahedrical form, or as two pyramids jointed by the base in such a manner that the celestial pyramid has thirteen heavens in the form of platforms in such a way that the zenith is the seventh platform; on the contrary, the infraworld pyramid has nine platforms. The sequence of the heavens comes to an end in the number 13 heaven, or the West side of the world, that is to say the Omeyocan or the Tamoanchan, whereas the ninth infraworld is the Apochcalocan. This is the point of the intercommunication between the celestial world and the infraworld, the place of Death and Birth. In order to develop that hypothesis the author has a great number of ethnographic testimonies taken from Totonacs, Tzotziles, Mayas and, along with this, from Southamerican areas, as it is the case of the Kogi, of Colombia. The author has also considered the evidence that proceeds from the ancient codices as well as numerous samples of sculptures and reliefs, especially from the Aztec culture.

  4. Constraining Effects of Brine Leakage from Carbon Sequestration Sites

    NASA Astrophysics Data System (ADS)

    Wunsch, A.; Navarre-Sitchler, A. K.; McCray, J. E.

    2011-12-01

    Research has shown that pressure build up associated with injection of CO2 into a deep saline aquifer has the potential to promote brine leakage into overlying formations. In order to understand and quantify chemical changes in an underground source of drinking water (USDW) invaded by deep saline brines, we analyzed over 90,000 brine geochemical data entries from the NETL NATCARB brine database to identify potential brine constituents of concern. Using a variety of statistical methods and EPA regulatory levels or standards (RLS) we narrowed the list of brine constituents of potential concern to USDWs to TDS, thallium, chloride, sulfate and arsenic. Somewhat surprisingly, the distribution of reported pH had a fairly narrow distribution around a median value of 7.4, with over 78% of values complying with EPA recommended secondary standard for drinking water acidity. The pH distribution implies that unlike pure CO2 leakage, far-field brine leakage (i.e., brine not in contact with CO2) is not expected to bear a low-pH signature, thus suggesting use of other means of geochemical monitoring for brine leakage, such as electrical conductivity. Geochemical mixing models of brine and dilute water were used to constrain mixing ratios where RLS values are exceeded for the TDS, thallium and chloride. TDS and chloride exceed the EPA secondary standards at a brine/USDW mixing ratio of 0.012 and 0.459, respectively. The thallium maximum contaminant level (MCL) is exceeded at a brine/USDW mixing ratio of 0.3753, smaller than the chloride mixing ratio. However, sorption and/or desorption processes may alter thallium concentrations along a leakage pathway resulting in lower concentrations in the aquifer than predicted by simple mixing models. While leakage into USDWs has received considerable attention, brine contamination of groundwater used for irrigation of agricultural crops is also an important area of research. Our calculations suggest that almost all crops grown in the United

  5. Apparatus for detecting leakage of liquid sodium

    DOEpatents

    Himeno, Yoshiaki

    1978-01-01

    An apparatus for detecting the leakage of liquid sodium includes a cable-like sensor adapted to be secured to a wall of piping or other equipment having sodium on the opposite side of the wall, and the sensor includes a core wire electrically connected to the wall through a leak current detector and a power source. An accidental leakage of the liquid sodium causes the corrosion of a metallic layer and an insulative layer of the sensor by products resulted from a reaction of sodium with water or oxygen in the atmospheric air so as to decrease the resistance between the core wire and the wall. Thus, the leakage is detected as an increase in the leaking electrical current. The apparatus is especially adapted for use in detecting the leakage of liquid sodium from sodium-conveying pipes or equipment in a fast breeder reactor.

  6. Solute Leakage Resulting from Leaf Desiccation

    PubMed Central

    Leopold, A. Carl; Musgrave, Mary E.; Williams, Kathleen M.

    1981-01-01

    The leakage of solutes from foliar tissue is utilized as a dynamic measure of apparent changes in membrane integrity in response to desiccation. It is found that rehydrating leaf discs of cowpea (Vigna sinensis [L.] Endl.) show increasing leakiness in proportion to the extent of prior desiccation, whereas Selaginella lepidophylla Spring., a resurrection plant, does not. The elevated leakage rate of cowpea after desiccation recovers with time, and the passage of time in the stressed condition results in reduced subsequent leakiness. These characteristics are interpreted as suggesting that the leakage of solute reflects the condition of cellular membranes, and that desiccation stress leads to lesions in the membranes. The kinetics of solute leakage is suggested as a simple means of following changes in membrane lesions and associated features of membrane repair and hardening. PMID:16662082

  7. [Bile leakage in laparoscopic cholecystectomy. Authors' experience].

    PubMed

    Sperlongano, P; Pisaniello, D; Corsale, I; Cozza, G

    1999-01-01

    The Authors report their experience of two patients with bile leakage following videocholecystectomy (VLC) among a series of 163 cases. Reviewing the Literature, they analyze possible causes and mechanisms of bile spillage occurring after VCL. They also suggest some guidelines for a safe VLC, stressing the importance of the routinary placement of the sub-hepatic drainage to remove 48 hours to early detect possible bile leakages after surgery.

  8. Technology evaluation for space station atmospheric leakage

    SciTech Connect

    Lemon, D.K.; Friesel, M.A.; Griffin, J.W.; Skorpik, J.R.; Shepard, C.L.; Antoniak, Z.I.; Kurtz, R.J.

    1990-02-01

    A concern in operation of a space station is leakage of atmosphere through seal points and through the walls as a result of damage from particle (space debris and micrometeoroid) impacts. This report describes a concept for a monitoring system to detect atmosphere leakage and locate the leak point. The concept is based on analysis and testing of two basic methods selected from an initial technology survey of potential approaches. 18 refs., 58 figs., 5 tabs.

  9. Subsurface Barrier Formation as a CO2 Leakage Mitigation Technology

    NASA Astrophysics Data System (ADS)

    Castaneda Herrera, C. A.; Stevens, G.; Haese, R. R.

    2015-12-01

    Long-term CO2 containment in a geological storage reservoir is a key criterion for successfully implementing carbon capture and storage (CCS), however, CO2 leakage through different pathways cannot be completely ruled out in some instances. In this study we investigate the conditions for reactive barrier formation as a technology to mitigate and remediate CO2 leakage. We propose to inject a liquid reagent consistent of an alkaline sodium-silicate solution on top of the storage caprock, which will lead to silica mineral precipitation when in contact with an acidic, CO2-enriched fluid. This reaction will create a barrier that seals the leakage by reducing the permeability. Preliminary modelling has shown that the density, viscosity and alkalinity of the reagent fluid are critical for a successful seal formation, whereas differences in formation water composition and in the rock mineral composition are less important. In order to study the reaction through experiments, different reagent solutions were prepared and characterised in terms of silica concentration, density, viscosity and buffer capacity. In a static, diffusion-controlled batch experiment we observed silica mineral precipitation in the outer layer of the piece of rock inhibiting further mixing of the two fluids and slowing down the initial reaction rate. Core-flood experiments will be carried out to simulate barrier formation under fluid flow conditions. Here, the sealing efficiency of the reaction will be continuously measured in terms of a change in permeability.

  10. Leakage Suppression in the Toric Code

    NASA Astrophysics Data System (ADS)

    Suchara, Martin; Cross, Andrew; Gambetta, Jay

    2015-03-01

    Quantum codes excel at correcting local noise but fail to correct leakage faults that excite qubits to states outside the computational space. Aliferis and Terhal have shown that an accuracy threshold exists for leakage faults using gadgets called leakage reduction units (LRUs). However, these gadgets reduce the threshold and increase experimental complexity, and the costs have not been thoroughly understood. We explore a variety of techniques for leakage resilience in topological codes. Our contributions are threefold. First, we develop a leakage model that differs in critical details from earlier models. Second, we use Monte-Carlo simulations to survey several syndrome extraction circuits. Third, given the capability to perform 3-outcome measurements, we present a dramatically improved syndrome processing algorithm. Our simulations show that simple circuits with one extra CNOT per qubit reduce the accuracy threshold by less than a factor of 4 when leakage and depolarizing noise rates are comparable. This becomes a factor of 2 when the decoder uses 3-outcome measurements. Finally, when the physical error rate is less than 2 ×10-4 , placing LRUs after every gate may achieve the lowest logical error rate. We expect that the ideas may generalize to other topological codes.

  11. EFFECTS OF LEAKAGE NEUTRAL PARTICLES ON SHOCKS

    SciTech Connect

    Ohira, Yutaka

    2012-10-20

    In this paper, we investigate effects of neutral particles on shocks propagating into the partially ionized medium. We find that for 120 km s{sup -1} < u {sub sh} < 3000 km s{sup -1} (u {sub sh} is the shock velocity), about 10% of upstream neutral particles leak into the upstream region from the downstream region. Moreover, we investigate how the leakage neutral particles affect the upstream structure of the shock and particle accelerations. Using four-fluid approximations (upstream ions, upstream neutral particles, leakage neutral particles, and pickup ions), we provide analytical solutions of the precursor structure due to leakage neutral particles. It is shown that the upstream flow is decelerated in the precursor region and the shock compression ratio becomes smaller than without leakage neutral particles, but the total compression ratio does not change. Even if leakage of neutral particles is small (a few percent of total upstream particles), this smaller compression ratio of the shock can explain steep gamma-ray spectra from young supernova remnants. Furthermore, leakage neutral particles could amplify the magnetic field and heat the upstream region.

  12. Revisiting the Dutch hypothesis.

    PubMed

    Postma, Dirkje S; Weiss, Scott T; van den Berge, Maarten; Kerstjens, Huib A M; Koppelman, Gerard H

    2015-09-01

    The Dutch hypothesis was first articulated in 1961, when many novel and advanced scientific techniques were not available, such as genomics techniques for pinpointing genes, gene expression, lipid and protein profiles, and the microbiome. In addition, computed tomographic scans and advanced analysis techniques to dissect (small) airways disease and emphysema were not available. At that time, the group of researchers under the visionary guidance of Professor N. G. M. Orie put forward that both genetic and environmental factors can determine whether one would have airway obstructive diseases, such as asthma and chronic obstructive pulmonary disease (COPD). Moreover, they stipulated that the phenotype of obstructive airway disease could be affected by sex and changes with aging. Orie and colleagues' call to carefully phenotype patients with obstructive airways diseases has been adopted by many current researchers in an attempt to determine the heterogeneity of both asthma and COPD to better define these diseases and optimize their treatment. The founders of the Dutch hypothesis were far ahead of their time, and we can learn from their insights. We should fully characterize all patients in our clinical practice and not just state that they have asthma, COPD, or asthma and COPD overlap syndrome. This detailed phenotyping can help in understanding these obstructive airway diseases and provide guidance for disease management.

  13. Heparin Leakage in Central Venous Catheters by Hemodynamic Transport

    NASA Astrophysics Data System (ADS)

    Barbour, Michael; McGah, Patrick; Gow, Kenneth; Aliseda, Alberto

    2014-11-01

    Central venous catheters (CVCs), placed in the superior vena cava for hemodialysis, are routinely filled with heparin, an anticoagulant, while not in use to maintain patency and prevent thrombus formation at the catheter tip. However, the heparin-lock procedure places the patient at risk for systemic bleeding incidences, as heparin is known to leak into the blood stream. We propose that the driving mechanism behind heparin leakage is advective-diffusive transport due to the pulsatile blood flow surrounding the catheter tip. This novel hypothesis is based on Planar Laser Induced Fluorescence (PLIF) measurements of heparin transport from a CVC placed inside an in vitro pulsatile flow loop and validated with CFD simulations. The results show an initial, fast (<10s), advection-dominated phase that rapidly depletes the concentration of heparin at the CVC tip, followed by a slow, diffusion-limited phase inside the catheter lumen, where concentration is still high, that is insufficient at replenishing the lost heparin at the tip. These results, which estimate leakage rates consistent with published in vivo data, predict that the concentration of heparin at the catheter tip is effectively zero for the majority of the interdialytic phase, rendering the heparin lock ineffective.

  14. Pharmacological characterization of the late phase reduction in lung functions and correlations with microvascular leakage and lung edema in allergen-challenged Brown Norway rats.

    PubMed

    Mauser, Peter J; House, Aileen; Jones, Howard; Correll, Craig; Boyce, Christopher; Chapman, Richard W

    2013-12-01

    Late phase airflow obstruction and reduction in forced vital capacity are characteristic features of human asthma. Airway microvascular leakage and lung edema are also present in the inflammatory phase of asthma, but the impact of this vascular response on lung functions has not been precisely defined. This study was designed to evaluate the role of increased lung microvascular leakage and edema on the late phase changes in forced vital capacity (FVC) and peak expiratory flow (PEF) in allergen-challenged Brown Norway rats using pharmacological inhibitors of the allergic inflammatory response. Rats were sensitized and challenged with ovalbumin aerosol and forced expiratory lung functions (FVC, PEF) and wet and dry lung weights were measured 48 h after antigen challenge. Ovalbumin challenge reduced FVC (63% reduction) and PEF (33% reduction) and increased wet (65% increase) and dry (51% increase) lung weights. The antigen-induced reduction in FVC and PEF was completely inhibited by oral treatment with betamethasone and partially attenuated by inhibitors of arachidonic acid metabolism including indomethacin (cyclooxygenase inhibitor), 7-TM and MK-7246 (CRTH2 antagonists) and montelukast (CysLT1 receptor antagonist). Antagonists of histamine H1 receptors (mepyramine) and 5-HT receptors (methysergide) had no significant effects indicating that these pre-formed mast cell mediators were not involved. There was a highly significant (P < 0.005) correlation for the inhibition of FVC reduction and increase in wet and dry lung weights by these pharmacological agents. These results strongly support the hypothesis that lung microvascular leakage and the associated lung edema contribute to the reduction in forced expiratory lung functions in antigen-challenged Brown Norway rats and identify an important role for the cyclooxygenase and lipoxygenase products of arachidonic acid metabolism in these responses.

  15. 49 CFR 192.723 - Distribution systems: Leakage surveys.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 3 2012-10-01 2012-10-01 false Distribution systems: Leakage surveys. 192.723... Distribution systems: Leakage surveys. (a) Each operator of a distribution system shall conduct periodic leakage surveys in accordance with this section. (b) The type and scope of the leakage control...

  16. 49 CFR 192.706 - Transmission lines: Leakage surveys.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 3 2011-10-01 2011-10-01 false Transmission lines: Leakage surveys. 192.706... Transmission lines: Leakage surveys. Leakage surveys of a transmission line must be conducted at intervals not... transports gas in conformity with § 192.625 without an odor or odorant, leakage surveys using leak...

  17. 49 CFR 192.723 - Distribution systems: Leakage surveys.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 3 2010-10-01 2010-10-01 false Distribution systems: Leakage surveys. 192.723... Distribution systems: Leakage surveys. (a) Each operator of a distribution system shall conduct periodic leakage surveys in accordance with this section. (b) The type and scope of the leakage control...

  18. 49 CFR 192.706 - Transmission lines: Leakage surveys.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 3 2013-10-01 2013-10-01 false Transmission lines: Leakage surveys. 192.706... Transmission lines: Leakage surveys. Leakage surveys of a transmission line must be conducted at intervals not... transports gas in conformity with § 192.625 without an odor or odorant, leakage surveys using leak...

  19. 49 CFR 192.723 - Distribution systems: Leakage surveys.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 3 2011-10-01 2011-10-01 false Distribution systems: Leakage surveys. 192.723... Distribution systems: Leakage surveys. (a) Each operator of a distribution system shall conduct periodic leakage surveys in accordance with this section. (b) The type and scope of the leakage control...

  20. 49 CFR 192.706 - Transmission lines: Leakage surveys.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 3 2012-10-01 2012-10-01 false Transmission lines: Leakage surveys. 192.706... Transmission lines: Leakage surveys. Leakage surveys of a transmission line must be conducted at intervals not... transports gas in conformity with § 192.625 without an odor or odorant, leakage surveys using leak...

  1. 49 CFR 192.706 - Transmission lines: Leakage surveys.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 3 2010-10-01 2010-10-01 false Transmission lines: Leakage surveys. 192.706... Transmission lines: Leakage surveys. Leakage surveys of a transmission line must be conducted at intervals not... transports gas in conformity with § 192.625 without an odor or odorant, leakage surveys using leak...

  2. 49 CFR 192.723 - Distribution systems: Leakage surveys.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 3 2013-10-01 2013-10-01 false Distribution systems: Leakage surveys. 192.723... Distribution systems: Leakage surveys. (a) Each operator of a distribution system shall conduct periodic leakage surveys in accordance with this section. (b) The type and scope of the leakage control...

  3. 49 CFR 192.723 - Distribution systems: Leakage surveys.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 3 2014-10-01 2014-10-01 false Distribution systems: Leakage surveys. 192.723... Distribution systems: Leakage surveys. (a) Each operator of a distribution system shall conduct periodic leakage surveys in accordance with this section. (b) The type and scope of the leakage control...

  4. 21 CFR 870.2640 - Portable leakage current alarm.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Portable leakage current alarm. 870.2640 Section... leakage current alarm. (a) Identification. A portable leakage current alarm is a device used to measure the electrical leakage current between any two points of an electrical system and to sound an alarm...

  5. Determination of leakage areas in nuclear piping

    SciTech Connect

    Keim, E.

    1997-04-01

    For the design and operation of nuclear power plants the Leak-Before-Break (LBB) behavior of a piping component has to be shown. This means that the length of a crack resulting in a leak is smaller than the critical crack length and that the leak is safely detectable by a suitable monitoring system. The LBB-concept of Siemens/KWU is based on computer codes for the evaluation of critical crack lengths, crack openings, leakage areas and leakage rates, developed by Siemens/KWU. In the experience with the leak rate program is described while this paper deals with the computation of crack openings and leakage areas of longitudinal and circumferential cracks by means of fracture mechanics. The leakage areas are determined by the integration of the crack openings along the crack front, considering plasticity and geometrical effects. They are evaluated with respect to minimum values for the design of leak detection systems, and maximum values for controlling jet and reaction forces. By means of fracture mechanics LBB for subcritical cracks has to be shown and the calculation of leakage areas is the basis for quantitatively determining the discharge rate of leaking subcritical through-wall cracks. The analytical approach and its validation will be presented for two examples of complex structures. The first one is a pipe branch containing a circumferential crack and the second one is a pipe bend with a longitudinal crack.

  6. Sustainable management of leakage from wastewater pipelines.

    PubMed

    DeSilva, D; Burn, S; Tjandraatmadja, G; Moglia, M; Davis, P; Wolf, L; Held, I; Vollertsen, J; Williams, W; Hafskjold, L

    2005-01-01

    Wastewater pipeline leakage is an emerging concern in Europe, especially with regards to the potential effect of leaking effluent on groundwater contamination and the effects infiltration has on the management of sewer reticulation systems. This paper describes efforts by Australia, in association with several European partners, towards the development of decision support tools to prioritize proactive rehabilitation of wastewater pipe networks to account for leakage. In the fundamental models for the decision support system, leakage is viewed as a function of pipeline system deterioration. The models rely on soil type identification across the service area to determine the aggressiveness of the pipe environment and for division of the area into zones based on pipe properties and operational conditions. By understanding the interaction between pipe materials, operating conditions, and the pipe environment in the mechanisms leading to pipe deterioration, the models allow the prediction of leakage rates in different zones across a network. The decision support system utilizes these models to predict the condition of pipes in individual zones, and to optimize the utilization of rehabilitation resources by targeting the areas with the highest leakage rates.

  7. Air heater leakage: worse than you think

    SciTech Connect

    Guffre, J.

    2006-04-15

    Every good engineer knows that you cannot control what you cannot measure. In the case of rotary regenerative air heaters, many plants fail to limit the negative impact of heater leakage because they use measurement procedures and/or devices that fail to take into account its indirect effects. For a 500 MW coal-fired plant the heat energy that air heaters capture and recycle amounts to about 60% of that existing in the boiler, equivalent to 1.5 Btu per hour. This article explains the importance of accurately measuring leakage levels and the need to use modern seals to make heaters air-tight. 4 figs.

  8. Nedley Depression Hit Hypothesis

    PubMed Central

    Nedley, Neil; Ramirez, Francisco E.

    2014-01-01

    Depression is often diagnosed using the Diagnostic and Statistical Manual of Mental Disorders Fifth Edition (DSM-5) criteria. We propose how certain lifestyle choices and non-modifiable factors can predict the development of depression. We identified 10 cause categories (hits or “blows” to the brain) and theorize that four or more active hits could trigger a depression episode. Methods. A sample of 4271 participants from our community-based program (70% female; ages 17-94 years) was assessed at baseline and at the eighth week of the program using a custom test. Ten cause categories were examined as predictors of depression are (1) Genetic, (2)Developmental, (3)Lifestyle, (4)Circadian Rhythm, (5)Addiction, (6)Nutrition, (7)Toxic, (8)Social/Complicated Grief, (9)Medical Condition, and (10)Frontal Lobe. Results. The relationship between the DSM-5 score and a person having four hits categories in the first program week showed a sensitivity of 89.98 % (95% CI: 89.20 % - 90.73%), specificity 48.84% (CI 45.94-51.75) and Matthew Correlation Coefficient (MCC) .41 . For the eight-week test, the results showed a sensitivity 83.6% (CI 81.9-85.5), specificity 53.7% (CI 51.7-55.6) and MCC .38. Overall, the hits that improved the most from baseline after the eighth week were: Nutrition (47%), Frontal lobe (36%), Addiction (24%), Circadian rhythm (24%), Lifestyle (20%), Social (12%) and Medical (10%). Conclusions. The Nedley four-hit hypothesis seems to predict a depressive episode and correlates well with the DSM-5 criteria with good sensitivity and MCC but less specificity. Identifying these factors and applying lifestyle therapies could play an important role in the treatment of depressed individuals. PMID:27885322

  9. Geologic Storage of CO2: Leakage Pathways and Environmental Risks

    NASA Astrophysics Data System (ADS)

    Celia, M. A.; Peters, C. A.; Bachu, S.

    2002-05-01

    Geologic storage of CO2 appears to be an attractive option for carbon mitigation because it offers sufficient capacity to solve the problem, and it can be implemented with existing technology. Among the list of options for storage sites, depleted hydrocarbon reservoirs and deep saline aquifers are two major categories. While injection into hydrocarbon reservoirs offers immediate possibilities, especially in the context of enhanced oil recovery, it appears that deep saline aquifers provide the extensive capacity necessary to solve the problem over the decade to century time scale. Capacity and technology argue favorably for this option, but remaining obstacles to implementation include capture technologies, overall economic considerations, and potential environmental consequences of the injection. Of these, the environmental questions may be most difficult to solve. Experience from CO2 floods for enhanced oil recovery and from CO2 and acid gas disposal operations indicates that geological storage of CO2 is safe over the short term for comparatively small amounts of CO2. However, there is no experience to date regarding the long-term fate and safety of the large volumes of CO2 that must be injected to significantly reduce atmospheric emissions. In order to make proper evaluation of environmental risks, the full range of possible environmental consequences must be considered. Most of these environmental concerns involve migration and leakage of CO2 into shallow portions of the subsurface and eventually into the atmosphere. In shallow subsurface zones, elevated levels of carbon dioxide can cause pH changes, leading to possible mobilization of ground-water contaminants including metals. In the unsaturated zone, vegetation can be adversely affected, as can other ecosystem components. At the land surface, elevated levels of CO2 can lead to asphyxiation in humans and other animals. And finally, in the atmosphere, CO2 that leaks from underground diminishes the effectiveness

  10. Control of Air Leakage in Buildings.

    ERIC Educational Resources Information Center

    Wilson, A. Grant

    This discussion of air leakage emphasizes cause and provides suggestions for elimination of undesirable effects. Cause parameters described are--(1) pressure differential, (2) building shape, (3) temperature differential, (4) opening sizes, (5) mechanical system pressures, and (6) climatic factors. Effects discussed are--(1) increased mechanical…

  11. Vacuum test fixture improves leakage rate measurements

    NASA Technical Reports Server (NTRS)

    Maier, H.; Marx, H.

    1966-01-01

    Cylindrical chamber, consisting of two matching halves, forms a vacuum test fixture for measuring leakage rates of individual connections, brazed joints, and entrance ports used in closed fluid flow line systems. Once the chamber has been sufficiently evacuated, atmospheric pressure holds the two halves together.

  12. Measurements of the atmospheric neutron leakage rate

    NASA Technical Reports Server (NTRS)

    Lockwood, J. A.; Ifedili, S. O.; Jenkins, R. W.

    1973-01-01

    The atmospheric neutron leakage rate in the energy range from 0.01 to 10,000,000 eV has been measured as a function of latitude, altitude, and time with a neutron detector on board the Ogo 6 satellite. The latitude dependence of the neutron leakage is in reasonable agreement with that predicted by Lingenfelter (1963) and Light et al. (1973) if the neutron energy spectrum has the shape calculated by Newkirk (1963). The change in the neutron latitude dependence with the cosmic ray modulation agrees with the predictions of Lingenfelter and Light et al. For several solar proton events enhancements were observed in the neutron counting rates at lambda greater than or equal to 70 deg. Such events, however, provide an insignificant injection of protons at E less than or equal to 20 MeV into the radiation belts. An isotropic angular distribution of the neutron leakage in the energy range from 0.1 keV to 10 MeV best fits the observed altitude dependence of the neutron leakage flux.

  13. The migratory fascia hypothesis.

    PubMed

    Lelean, Peter

    2009-10-01

    its possible implications for lumbo-pelvic function. Although a review of anatomy atlases has failed to reveal mention of migratory fascia, the author respectfully suggests that dissection, specifically aimed at this task, may demonstrate its presence. It is also suggested that a retrospective review of lumbo-pelvic MRI records be initiated to identify the presence of this proposed fascial feature in the general population. Finally, magnetic resonance elastography may be useful in defining areas of increased muscular tension, in order to test the migratory fascia hypothesis.

  14. Cuff leakage, not paravalvular leakage, in the Carpentier Edwards PERIMOUNT Magna Ease aortic bioprosthesis.

    PubMed

    Tokunaga, Shigehiko; Cho, Tomoki; Izubuchi, Ryo; Masuda, Munetaka

    2015-12-01

    Though the Carpentier Edwards PERIMOUNT Magna Ease valve is a bioprosthesis with documented excellent haemodynamics and easy implantability, this valve has a gap between the cobalt-chromium-nickel alloy stent and silicone sewing ring. This gap, which is widest just below each of the three commissural struts, lacks silicone and leaves the two-layer polytetrafluoroethylene fabric unsupported and unprotected. If the needle of a valve suture is placed in this structurally weak area of the sewing ring, the resultant fabric tear may result in a true cuff leakage, not the usual paravalvular leakage. We describe this pitfall in the context of a recent operation to alert surgeons everywhere that suture placement too close to the stent (missing the silicone sewing ring) can result in postoperative cuff leakage. We need to be very careful to include the silicone ring in each stitch to prevent injury to the valve cuff of this prosthesis and to avoid cuff leakage.

  15. Is the Aluminum Hypothesis Dead?

    PubMed Central

    2014-01-01

    The Aluminum Hypothesis, the idea that aluminum exposure is involved in the etiology of Alzheimer disease, dates back to a 1965 demonstration that aluminum causes neurofibrillary tangles in the brains of rabbits. Initially the focus of intensive research, the Aluminum Hypothesis has gradually been abandoned by most researchers. Yet, despite this current indifference, the Aluminum Hypothesis continues to attract the attention of a small group of scientists and aluminum continues to be viewed with concern by some of the public. This review article discusses reasons that mainstream science has largely abandoned the Aluminum Hypothesis and explores a possible reason for some in the general public continuing to view aluminum with mistrust. PMID:24806729

  16. 40 CFR 91.324 - Analyzer leakage check.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... Analyzer leakage check. (a) Vacuum side leak check. (1) Check any location within the analysis system where a vacuum leak could affect the test results. (2) The maximum allowable leakage rate on the...

  17. 40 CFR 91.324 - Analyzer leakage check.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... Analyzer leakage check. (a) Vacuum side leak check. (1) Check any location within the analysis system where a vacuum leak could affect the test results. (2) The maximum allowable leakage rate on the...

  18. 40 CFR 91.324 - Analyzer leakage check.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... Analyzer leakage check. (a) Vacuum side leak check. (1) Check any location within the analysis system where a vacuum leak could affect the test results. (2) The maximum allowable leakage rate on the...

  19. 40 CFR 91.324 - Analyzer leakage check.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... Analyzer leakage check. (a) Vacuum side leak check. (1) Check any location within the analysis system where a vacuum leak could affect the test results. (2) The maximum allowable leakage rate on the...

  20. 40 CFR 91.324 - Analyzer leakage check.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... Analyzer leakage check. (a) Vacuum side leak check. (1) Check any location within the analysis system where a vacuum leak could affect the test results. (2) The maximum allowable leakage rate on the...

  1. Nonlinear Acoustics Used To Reduce Leakage Flow

    NASA Technical Reports Server (NTRS)

    Daniels, Christopher C.; Steinetz, Bruce M.

    2004-01-01

    Leakage and wear are two fundamental problems in all traditional turbine seals that contribute to an engine's inefficiency. The solutions to seal leakage and wear conflict in the conventional design space. Reducing the clearance between the seal and rotating shaft reduces leakage but increases wear because of increased contact incidents. Increasing the clearance to reduce the contact between parts reduces wear but increases parasitic leakage. The goal of this effort is to develop a seal that restricts leakage flow using acoustic pressure while operating in a noncontacting manner, thereby increasing life. In 1996, Dr. Timothy Lucas announced his discovery of a method to produce shock-free high-amplitude pressure waves. For the first time, the formation of large acoustic pressures was possible using dissonant resonators. A pre-prototype acoustic seal developed at the NASA Glenn Research Center exploits this fundamental acoustic discovery: a specially shaped cavity oscillated at the contained fluid's resonant frequency produces high-amplitude acoustic pressure waves of a magnitude approaching those required of today's seals. While the original researchers are continuing their development of acoustic pumps, refrigeration compressors, and electronic thermal management systems using this technology, the goal of researchers at Glenn is to apply these acoustic principles to a revolutionary sealing device. When the acoustic resonator shape is optimized for the sealing device, the flow from a high-pressure cavity to a low-pressure cavity will be restricted by a series of high-amplitude standing pressure waves of higher pressure than the pressure to be sealed. Since the sealing resonator cavity will not touch the adjacent sealing structures, seal wear will be eliminated, improving system life. Under a cooperative agreement between Glenn and the Ohio Aerospace Institute (OAI), an acoustic-based pre-prototype seal was demonstrated for the first time. A pressurized cavity was

  2. Scintigraphic detection of urinary leakage after kidney transplantation.

    PubMed

    DeLange, E E; Pauwels, E K; Lobatto, S; Tjon Pian Gi-van Loon, C E; van Hooff, J P

    1982-01-01

    Urinary leakage after kidney transplantation is a serious complication. In a retrospective study we analyzed 8 relevant cases of 14 patients with urinary leakage. In these eight patients kidney scintigraphy indicated the presence of urinary extravasation. Compared with other imaging modalities such as IV urography, cystography and ultrasound, scintigraphy seems to be an easy and safe method to detect urinary leakage. Moreover scintigraphic examination may suggest leakage, while this may not be clinically evident or suspected.

  3. Trending of Overboard Leakage of ISS Cabin Atmosphere

    NASA Technical Reports Server (NTRS)

    Schaezler, Ryan N.; Cook, Anthony J.; Leonard, Daniel J.; Ghariani, Ahmed

    2011-01-01

    The International Space Station (ISS) overboard leakage of cabin atmosphere is continually tracked to identify new or aggravated leaks and to provide information for planning of nitrogen supply to the ISS. The overboard leakage is difficult to trend with various atmosphere constituents being added and removed. Changes to nitrogen partial pressure is the nominal means of trending the overboard leakage. This paper summarizes the method of the overboard leakage trending and presents findings from the trending.

  4. Measurement Methods to Determine Air Leakage Between Adjacent Zones

    SciTech Connect

    Hult, Erin L.; Dickerhoff, Darryl J.; Price, Phillip N.

    2012-09-01

    Air leakage between adjacent zones of a building can lead to indoor air quality and energy efficiency concerns, however there is no existing standard for measuring inter-zonal leakage. In this study, synthesized data and field measurements are analyzed in order to explore the uncertainty associated with different methods for collecting and analyzing fan pressurization measurements to calculate interzone leakage.

  5. 49 CFR 192.706 - Transmission lines: Leakage surveys.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 3 2014-10-01 2014-10-01 false Transmission lines: Leakage surveys. 192.706... Transmission lines: Leakage surveys. Leakage surveys of a transmission line must be conducted at intervals not exceeding 15 months, but at least once each calendar year. However, in the case of a transmission line...

  6. Social Hypothesis Testing: Another Look.

    ERIC Educational Resources Information Center

    Mersmann, Harry J.

    Social hypothesis testing is the process by which individuals make judgments about what other people do, think, or say. In an attempt to replicate Snyder and Swann's (1978) research and to examine the relationship of certain personality traits to different hypothesis testing strategies, 86 college students made selections from a list of questions…

  7. Threshold Hypothesis: Fact or Artifact?

    ERIC Educational Resources Information Center

    Karwowski, Maciej; Gralewski, Jacek

    2013-01-01

    The threshold hypothesis (TH) assumes the existence of complex relations between creative abilities and intelligence: linear associations below 120 points of IQ and weaker or lack of associations above the threshold. However, diverse results have been obtained over the last six decades--some confirmed the hypothesis and some rejected it. In this…

  8. Efficient quantum dialogue without information leakage

    NASA Astrophysics Data System (ADS)

    Yin, Ai-Han; Tang, Zhi-Hui; Chen, Dong

    2015-02-01

    A two-step quantum dialogue scheme is put forward with a class of three-qubit W state and quantum dense coding. Each W state can carry three bits of secret information and the measurement result is encrypted without information leakage. Furthermore, we utilize the entangle properties of W state and decoy photon checking technique to realize three-time channel detection, which can improve the efficiency and security of the scheme.

  9. Gas pipeline leakage detection based on PZT sensors

    NASA Astrophysics Data System (ADS)

    Zhu, Junxiao; Ren, Liang; Ho, Siu-Chun; Jia, Ziguang; Song, Gangbing

    2017-02-01

    In this paper, an innovative method for rapid detection and location determination of pipeline leakage utilizing lead zirconate titanate (PZT) sensors is proposed. The negative pressure wave (NPW) is a stress wave generated by leakage in the pipeline, and propagates along the pipeline from the leakage point to both ends. Thus the NPW is associated with hoop strain variation along the pipe wall. PZT sensors mounted on the pipeline were used to measure the strain variation and allowed accurate (within 2% error) and repeatable location (within 4% variance) of five manually controlled leakage points. Experimental results have verified the effectiveness and the location accuracy for leakage in a 55 meter long model pipeline.

  10. Observation of anomalous leakage increase of narrow and short BCPMOS

    NASA Astrophysics Data System (ADS)

    Xu, Y. Z.; Pohland, O.; Cai, C.; Puchner, H.

    2004-07-01

    Leakage performance of BCPMOS (Buried channel PMOS) is investigated by experimentally varying the LDD implant conditions. An anomalous leakage increase with Boron LDD implant is observed for a small geometry (narrow and short) PMOS. Experimental results indicate that the increase of leakage current for narrow and short channel PMOS can be explained by boron piling up at the edge of STI isolation and from source/drain towards the middle of channel. Further confirmation of boron piling up is proven by the surface channel NMOS threshold voltage. Based on the leakage sensitivity, BCPMOS LDD is optimized to reduce leakage current for the small geometry transistors.

  11. Alopecia associated with unexpected leakage from electron cone

    SciTech Connect

    Wen, B.C.; Pennington, E.C.; Hussey, D.H.; Jani, S.K.

    1989-06-01

    Excessive irradiation due to unexpected leakage was found on a patient receiving electron beam therapy. The cause of this leakage was analyzed and the amount of leakage was measured for different electron beam energies. The highest leakage occurred with a 6 x 6 cm cone using a 12 MeV electron beam. The leakage dose measured along the side of the cone could be as great as 40%. Until the cones are modified or redesigned, it is advised that all patient setups be carefully reviewed to assure that no significant patient areas are in the side scatter region.

  12. Measuring and Suppressing Quantum State Leakage in a Superconducting Qubit

    NASA Astrophysics Data System (ADS)

    Chen, Zijun; Kelly, Julian; Quintana, Chris; Barends, R.; Campbell, B.; Chen, Yu; Chiaro, B.; Dunsworth, A.; Fowler, A. G.; Lucero, E.; Jeffrey, E.; Megrant, A.; Mutus, J.; Neeley, M.; Neill, C.; O'Malley, P. J. J.; Roushan, P.; Sank, D.; Vainsencher, A.; Wenner, J.; White, T. C.; Korotkov, A. N.; Martinis, John M.

    2016-01-01

    Leakage errors occur when a quantum system leaves the two-level qubit subspace. Reducing these errors is critically important for quantum error correction to be viable. To quantify leakage errors, we use randomized benchmarking in conjunction with measurement of the leakage population. We characterize single qubit gates in a superconducting qubit, and by refining our use of derivative reduction by adiabatic gate pulse shaping along with detuning of the pulses, we obtain gate errors consistently below 1 0-3 and leakage rates at the 1 0-5 level. With the control optimized, we find that a significant portion of the remaining leakage is due to incoherent heating of the qubit.

  13. Rationale for Measuring Duct Leakage Flows in Large Commercial Buildings

    SciTech Connect

    Wray, Craig P.; Diamond, Richard C.; Sherman, Max H.

    2005-07-01

    Industry-wide methods of assessing duct leakage are based on duct pressurization tests, and focus on ''high pressure'' ducts. Even though ''low pressure'' ducts can be a large fraction of the system and tend to be leaky, few guidelines or construction specifications require testing these ducts. We report here on the measured leakage flows from ten large commercial duct systems at operating conditions: three had low leakage (less than 5% of duct inlet flow), and seven had substantial leakage (9 to 26%). By comparing these flows with leakage flows estimated using the industry method, we show that the latter method by itself is not a reliable indicator of whole-system leakage flow, and that leakage flows need to be measured.

  14. Reserves in Context: Planning for Leakage from Protected Areas

    PubMed Central

    Renwick, Anna R.; Bode, Michael; Venter, Oscar

    2015-01-01

    When protected areas reduce threats within their boundaries, they often displace a portion of these threats into adjacent areas through a process known as ‘leakage’, undermining conservation objectives. Using theoretical models and a case study of terrestrial mammals in Indonesia, we develop the first theoretical explanation of how leakage impacts conservation actions, and highlight conservation strategies that mitigate these impacts. Although leakage is a socio-economic process, we demonstrate that its negative impacts are also affected by the distribution of species, with leakage having larger impacts in landscapes with homogeneous distribution of species richness. Moreover, leakage has a greater negative effect when conservation strategies are implemented opportunistically, even creating the potential for perversely negative consequences from protected area establishment. Leakage thereby increases the relative benefits of systematic conservation planning over opportunism, especially in areas with high leakage and heterogeneously distributed species. Although leakage has the potential to undermine conservation actions, conservation planning can minimize this risk. PMID:26053163

  15. FELERION: a new approach for leakage power reduction

    NASA Astrophysics Data System (ADS)

    R, Anjana; Somkuwar, Ajay

    2014-12-01

    The circuit proposed in this paper simultaneously reduces the sub threshold leakage power and saves the state of art aspect of the logic circuits. Sleep transistors and PMOS-only logic are used to further reduce the leakage power. Sleep transistors are used as the keepers to reduce the sub threshold leakage current providing the low resistance path to the output. PMOS-only logic is used between the pull up and pull down devices to mitigate the leakage power further. Our proposed fast efficient leakage reduction circuit not only reduces the leakage current but also reduces the power dissipation. Power and delay are analyzed at the 32 nm BSIM4 model for a chain of four inverters, NAND, NOR and ISCAS-85 c17 benchmark circuits using DSCH3 and the Microwind tool. The simulation results reveal that our proposed approach mitigates leakage power by 90%-94% as compared to the conventional approach.

  16. Simulation of permeability evolution of leakage pathway in carbonate-rich caprocks in carbon sequestration

    NASA Astrophysics Data System (ADS)

    Guo, B.; Fitts, J. P.; Dobossy, M. E.; Peters, C. A.

    2013-12-01

    the Michigan basin at an injection rate of 1 Mt/y. As an example, for a CVF value of 5%, the brine leakage rate after fifty years for a leakage pathway 1,000 m distance from the injection well is 0.88 kg/s, which is 2.4% larger than if there were no geochemical evolution of the permeability. In a sensitivity analysis with regard to the distance between the leakage pathway and the injection well, it was found that the cumulative leakage first increases with the distance and the relationship reverses after a certain distance. When the leakage pathway is farther away, the pressure increment drops leading to less acid brine flow; meanwhile, the time before the CO2 plume reaches the pathway is longer and this lengthens the reaction time with brine. Thirdly, we explored the role that SO2 would play if it were present as a co-injectant in carbon sequestration. The reaction considered is SO2 hydrolysis to form sulfurous acid. We expect the sulfurous acid will erode the calcite faster than carbonic acid because it is a stronger acid. Contrary to intuition, the simulation results showed a decrease in permeability due to CaSO3 precipitation in replacement of CaCO3, as CaSO3 has a larger molar volume.

  17. EVA Suit Microbial Leakage Investigation Project

    NASA Technical Reports Server (NTRS)

    Falker, Jay; Baker, Christopher; Clayton, Ronald; Rucker, Michelle

    2016-01-01

    The objective of this project is to collect microbial samples from various EVA suits to determine how much microbial contamination is typically released during simulated planetary exploration activities. Data will be released to the planetary protection and science communities, and advanced EVA system designers. In the best case scenario, we will discover that very little microbial contamination leaks from our current or prototype suit designs, in the worst case scenario, we will identify leak paths, learn more about what affects leakage--and we'll have a new, flight-certified swab tool for our EVA toolbox.

  18. Detecting margin leakage of dental composite restorations

    SciTech Connect

    Wu, W.; Cobb, E.; Dermann, K.; Rupp, N.W.

    1983-01-01

    The degree of microleakage between a restoration and the cavity wall is difficult to quantify objectively. A silver-staining method is used and compared to the radioisotope method with results that indicate a superior definition and more accurate evaluation of microleakage. In addition to the accuracy, two advantages are presented: (1) scoring of the leakage can be refined and divided into more precise numbers, and (2) teeth can be observed directly in a microscope without resorting to the indirect interpretation of film or photograph.

  19. Analysis of U.S. residential air leakage database

    SciTech Connect

    Chan, Wanyu R.; Price, Phillip N.; Sohn, Michael D.; Gadgil, Ashok J.

    2003-07-01

    The air leakage of a building envelope can be determined from fan pressurization measurements with a blower door. More than 70,000 air leakage measurements have been compiled into a database. In addition to air leakage, the database includes other important characteristics of the dwellings tested, such as floor area, year built, and location. There are also data for some houses on the presence of heating ducts, and floor/basement construction type. The purpose of this work is to identify house characteristics that can be used to predict air leakage. We found that the distribution of leakage normalized with floor area of the house is roughly lognormal. Year built and floor area are the two most significant factors to consider when predicting air leakage: older and smaller houses tend to have higher normalized leakage areas compared to newer and larger ones. Results from multiple linear regression of normalized leakage with respect to these two factors are presented for three types of houses: low-income, energy-efficient, and conventional. We demonstrate a method of using the regression model in conjunction with housing characteristics published by the US Census Bureau to derive a distribution that describes the air leakage of the single-family detached housing stock. Comparison of our estimates with published datasets of air exchange rates suggests that the regression model generates accurate estimates of air leakage distribution.

  20. Predicting Envelope Leakage in Attached Dwellings (Fact Sheet)

    SciTech Connect

    Not Available

    2013-11-01

    The most common method of measuring air leakage is to perform single (or solo) blower door pressurization and/or depressurization test. In detached housing, the single blower door test measures leakage to the outside. In attached housing, however, this "solo" test method measures both air leakage to the outside and air leakage between adjacent units through common surfaces. Although minimizing leakage to neighboring units is highly recommended to avoid indoor air quality issues between units, reduce pressure differentials between units, and control stack effect, the energy benefits of air sealing can be significantly overpredicted if the solo air leakage number is used in the energy analysis. Guarded blower door testing is more appropriate for isolating and measuring leakage to the outside in attached housing. This method uses multiple blower doors to depressurize adjacent spaces to the same level as the unit being tested. Maintaining a neutral pressure across common walls, ceilings, and floors acts as a "guard" against air leakage between units. The resulting measured air leakage in the test unit is only air leakage to the outside. Although preferred for assessing energy impacts, the challenges of performing guarded testing can be daunting.

  1. Geologic Carbon Sequestration: Leakage Potential and Policy Implications

    NASA Astrophysics Data System (ADS)

    Bielicki, J. M.; Peters, C. A.; Fitts, J. P.; Wilson, E. J.

    2014-12-01

    The geologic reservoirs that could be used for long-term sequestration of carbon dioxide (CO2) may have natural or manmade pathways that allow injected CO2, or the brine it displaces, to leak into overlying formations. Using a basin-scale leakage estimation model, we investigated the geophysical parameters that govern this leakage, and the resulting accumulations of leaked fluids in overlying formations. The results are discussed in the context of two polices aimed at governing long-term sequestration and protecting groundwater: the U.S. DOE guideline for storage permanence and the U.S. EPA UIC Program Class VI Rule. For a case study of CO2 injection into the Mt. Simon sandstone in the Michigan sedimentary basin, we showed that (1) the U.S. DOE guideline would allow for more leakage from larger injection projects than for smaller ones; (2) leakage amounts are determined mostly by well leakage permeability rather than by variation in formation permeabilities; (3) numerous leaking wells with anomalously high leakage permeabilities are necessary in order to achieve substantial leakage rates; (4) leakage can reach potable groundwater but intervening stratigraphic traps reduce the amount to be multiple orders of magnitude less than the leakage out of the reservoir, and (5) this leakage can reduce the Area of Review that is defined by the U.S. EPA as the area within which leakage can threaten groundwater. In summary, leakage that exceeds the U.S. DOE storage permanence goal would occur only under extreme conditions, the amount that reaches shallow potable groundwater may be inconsequential from a pollution standpoint, and leakage may be beneficial. Future federal policies should be harmonized to achieve the dual goals of protecting groundwater while allowing for adaptive management that incorporates uncertainties and imperfections inherent in geologic reservoirs.

  2. Modeling of the double leakage and leakage spillage flows in axial flow compressors

    NASA Astrophysics Data System (ADS)

    Du, Hui; Yu, Xianjun; Liu, Baojie

    2014-04-01

    A model to predict the double leakage and tip leakage leading edge spillage flows was developed. This model was combined by a TLV trajectory model and a TLV diameter model and formed as a function of compressor one-dimensional design parameters, i.e. the compressor massflow coefficient, ϕ and compressor loading coefficient, Ψ, and some critical blade geometrical parameters, i.e. blade solidity, σ, stagger angle, β S , blade chord length, C, and blade pitch length, S. By using this model, the double leakage and tip leakage leading edge spillage flow could be predicted even at the compressor preliminary design process. Considering the leading edge spillage flow usually indicates the inception of spike-type stall, i.e. the compressor is a tip critical design, this model could also be used as a tool to choose the critical design parameters for designers. At last, some experimental data from literature was used to validate the model and the results proved that the model was reliable.

  3. Optical imaging to map blood-brain barrier leakage

    NASA Astrophysics Data System (ADS)

    Jaffer, Hayder; Adjei, Isaac M.; Labhasetwar, Vinod

    2013-11-01

    Vascular leakage in the brain is a major complication associated with brain injuries and certain pathological conditions due to disruption of the blood-brain barrier (BBB). We have developed an optical imaging method, based on excitation and emission spectra of Evans Blue dye, that is >1000-fold more sensitive than conventional ultraviolet spectrophotometry. We used a rat thromboembolic stroke model to validate the usefulness of our method for vascular leakage. Optical imaging data show that vascular leakage varies in different areas of the post-stroke brain and that administering tissue plasminogen activator causes further leakage. The new method is quantitative, simple to use, requires no tissue processing, and can map the degree of vascular leakage in different brain locations. The high sensitivity of our method could potentially provide new opportunities to study BBB leakage in different pathological conditions and to test the efficacy of various therapeutic strategies to protect the BBB.

  4. Tasman leakage in a fine-resolution ocean model

    NASA Astrophysics Data System (ADS)

    van Sebille, Erik; England, Matthew H.; Zika, Jan D.; Sloyan, Bernadette M.

    2012-03-01

    Tasman leakage, the westward flow of thermocline waters south of Australia from the Pacific to the Indian Ocean, is one of the lesser-studied of the inter-ocean exchanges. Here, some of the properties of the Tasman leakage are inferred from Lagrangian particles integrated using the three-dimensional velocity fields of the 1/10 degree resolution OFES model. The mean Tasman leakage in this model is 4.2 Sv, with a standard deviation of 4.3 Sv. The heat flux associated with this leakage lies in the range 0.08-0.18 PW. There is large variability in the Tasman leakage on both sub-weekly and inter-annual scales, but no trend over the 1983-1997 period. Despite the large weekly variability, with peaks of more than 20 Sv, it appears that less than half of the Tasman leakage is carried within eddies.

  5. Action perception as hypothesis testing.

    PubMed

    Donnarumma, Francesco; Costantini, Marcello; Ambrosini, Ettore; Friston, Karl; Pezzulo, Giovanni

    2017-04-01

    We present a novel computational model that describes action perception as an active inferential process that combines motor prediction (the reuse of our own motor system to predict perceived movements) and hypothesis testing (the use of eye movements to disambiguate amongst hypotheses). The system uses a generative model of how (arm and hand) actions are performed to generate hypothesis-specific visual predictions, and directs saccades to the most informative places of the visual scene to test these predictions - and underlying hypotheses. We test the model using eye movement data from a human action observation study. In both the human study and our model, saccades are proactive whenever context affords accurate action prediction; but uncertainty induces a more reactive gaze strategy, via tracking the observed movements. Our model offers a novel perspective on action observation that highlights its active nature based on prediction dynamics and hypothesis testing.

  6. The atomic hypothesis: physical consequences

    NASA Astrophysics Data System (ADS)

    Rivas, Martín

    2008-08-01

    The hypothesis that matter is made of some ultimate and indivisible objects, together with the restricted relativity principle, establishes a constraint on the kind of variables we are allowed to use for the variational description of elementary particles. We consider that the atomic hypothesis not only states the indivisibility of elementary particles, but also that these ultimate objects, if not annihilated, cannot be modified by any interaction so that all allowed states of an elementary particle are only kinematical modifications of any one of them. Therefore, an elementary particle cannot have excited states. In this way, the kinematical group of spacetime symmetries not only defines the symmetries of the system, but also the variables in terms of which the mathematical description of the elementary particles can be expressed in either the classical or the quantum mechanical description. When considering the interaction of two Dirac particles, the atomic hypothesis restricts the interaction Lagrangian to a kind of minimal coupling interaction.

  7. Argument as Hypothesis-Testing.

    ERIC Educational Resources Information Center

    Zarefsky, David

    The argumentative perspective enables rhetoric to function in a manner analagous to science or analytic philosophy, yielding reliable knowledge about nonempirical topics, which other methods cannot address. In short, argumentation is the equivalent of hypothesis-testing. Forensics should offer laboratory experience in developing this perspective…

  8. The Triple T Allergy Hypothesis

    PubMed Central

    2004-01-01

    The early induction of allergy is a complex process involving protective and destructive gene variants, environmental and nutritional co-factors as well as allergen exposure. Although critical doses, interactions and susceptible time frames have not been identified so far, late gestation and early childhood seem to be important time periods for allergic sensitization. At least three risk factors can be distinguished based on altered early Th1 lymphocyte development. First, the number of children with an inborn maturation defect may have increased since the beginning of the last century, when this condition would otherwise have had a lethal outcome without antibiotics and other modern health care (survival hypothesis). Second, another group of children in industrialized countries may have a deficit of environmental Th1 triggers during early life (hygiene hypothesis). A third factor may also be found predominantly in western societies. The prophylaxis of rickets with vitamin D has the apparent side effect of suppressing Th1 development (vitamin hypothesis). Experimental as well as epidemiological studies now provide evidence for the vitamin hypothesis, which is examined in this paper by a time-course analysis of vitamin D application in Germany. Also paper studies in Swedish anthroposophic school children, the Tristan da Cunha islanders, and Swiss, Austrian and Bavarian farmers may be linked to either excessive or absent early vitamin D exposure. PMID:15330454

  9. On the Weyl curvature hypothesis

    SciTech Connect

    Stoica, Ovidiu Cristinel

    2013-11-15

    The Weyl curvature hypothesis of Penrose attempts to explain the high homogeneity and isotropy, and the very low entropy of the early universe, by conjecturing the vanishing of the Weyl tensor at the Big-Bang singularity. In previous papers it has been proposed an equivalent form of Einstein’s equation, which extends it and remains valid at an important class of singularities (including in particular the Schwarzschild, FLRW, and isotropic singularities). Here it is shown that if the Big-Bang singularity is from this class, it also satisfies the Weyl curvature hypothesis. As an application, we study a very general example of cosmological models, which generalizes the FLRW model by dropping the isotropy and homogeneity constraints. This model also generalizes isotropic singularities, and a class of singularities occurring in Bianchi cosmologies. We show that the Big-Bang singularity of this model is of the type under consideration, and satisfies therefore the Weyl curvature hypothesis. -- Highlights: •The singularities we introduce are described by finite geometric/physical objects. •Our singularities have smooth Riemann and Weyl curvatures. •We show they satisfy Penrose’s Weyl curvature hypothesis (Weyl=0 at singularities). •Examples: FLRW, isotropic singularities, an extension of Schwarzschild’s metric. •Example: a large class of singularities which may be anisotropic and inhomogeneous.

  10. Fluid leakage near the percolation threshold

    NASA Astrophysics Data System (ADS)

    Dapp, Wolf B.; Müser, Martin H.

    2016-02-01

    Percolation is a concept widely used in many fields of research and refers to the propagation of substances through porous media (e.g., coffee filtering), or the behaviour of complex networks (e.g., spreading of diseases). Percolation theory asserts that most percolative processes are universal, that is, the emergent powerlaws only depend on the general, statistical features of the macroscopic system, but not on specific details of the random realisation. In contrast, our computer simulations of the leakage through a seal—applying common assumptions of elasticity, contact mechanics, and fluid dynamics—show that the critical behaviour (how the flow ceases near the sealing point) solely depends on the microscopic details of the last constriction. It appears fundamentally impossible to accurately predict from statistical properties of the surfaces alone how strongly we have to tighten a water tap to make it stop dripping and also how it starts dripping once we loosen it again.

  11. Fluid leakage near the percolation threshold

    PubMed Central

    Dapp, Wolf B.; Müser, Martin H.

    2016-01-01

    Percolation is a concept widely used in many fields of research and refers to the propagation of substances through porous media (e.g., coffee filtering), or the behaviour of complex networks (e.g., spreading of diseases). Percolation theory asserts that most percolative processes are universal, that is, the emergent powerlaws only depend on the general, statistical features of the macroscopic system, but not on specific details of the random realisation. In contrast, our computer simulations of the leakage through a seal—applying common assumptions of elasticity, contact mechanics, and fluid dynamics—show that the critical behaviour (how the flow ceases near the sealing point) solely depends on the microscopic details of the last constriction. It appears fundamentally impossible to accurately predict from statistical properties of the surfaces alone how strongly we have to tighten a water tap to make it stop dripping and also how it starts dripping once we loosen it again. PMID:26839261

  12. Torque Transmission Device at Zero Leakage

    NASA Technical Reports Server (NTRS)

    Hendricks, R. C.; Mullen, R. L.

    2005-01-01

    In a few critical applications, mechanical transmission of power by rotation at low speed is required without leakage at an interface. Herein we examine a device that enables torque to be transmitted across a sealed environmental barrier. The barrier represents the restraint membrane through which the torque is transmitted. The power is transferred through elastic deformation of a circular tube into an elliptical cross-section. Rotation of the principle axis of the ellipse at one end results in a commensurate rotation of an elliptical cross section at the other end of the tube. This transfer requires no rigid body rotation of the tube allowing a membrane to seal one end from the other. Both computational and experimental models of the device are presented.

  13. A quantitative methodology to assess the risks to human health from CO 2 leakage into groundwater

    NASA Astrophysics Data System (ADS)

    Siirila, Erica R.; Navarre-Sitchler, Alexis K.; Maxwell, Reed M.; McCray, John E.

    2012-02-01

    Leakage of CO 2 and associated gases into overlying aquifers as a result of geologic carbon capture and sequestration may have adverse impacts on aquifer drinking-water quality. Gas or aqueous-phase leakage may occur due to transport via faults and fractures, through faulty well bores, or through leaky confining materials. Contaminants of concern include aqueous salts and dissolved solids, gaseous or aqueous-phase organic contaminants, and acidic gas or aqueous-phase fluids that can liberate metals from aquifer minerals. Here we present a quantitative risk assessment framework to predict potential human health risk from CO 2 leakage into drinking water aquifers. This framework incorporates the potential release of CO 2 into the drinking water aquifer; mobilization of metals due to a decrease in pH; transport of these metals down gradient to municipal receptors; distributions of contaminated groundwater to multiple households; and exposure and health risk to individuals using this water for household purposes. Additionally, this framework is stochastic, incorporates detailed variations in geological and geostatistical parameters and discriminates between uncertain and variable parameters using a two-stage, or nested, Monte Carlo approach. This approach is demonstrated using example simulations with hypothetical, yet realistic, aquifer characteristics and leakage scenarios. These example simulations show a greater risk for arsenic than for lead for both cancer and non-cancer endpoints, an unexpected finding. Higher background groundwater gradients also yield higher risk. The overall risk and the associated uncertainty are sensitive to the extent of aquifer stratification and the degree of local-scale dispersion. These results all highlight the importance of hydrologic modeling in risk assessment. A linear relationship between carcinogenic and noncarcinogenic risk was found for arsenic and suggests action levels for carcinogenic risk will be exceeded in exposure

  14. 49 CFR 178.345-13 - Pressure and leakage tests.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... adjacent cargo tanks empty and at atmospheric pressure. Each closure, except pressure relief devices and... 49 Transportation 3 2011-10-01 2011-10-01 false Pressure and leakage tests. 178.345-13 Section 178... Specifications for Containers for Motor Vehicle Transportation § 178.345-13 Pressure and leakage tests. (a)...

  15. 49 CFR 178.345-13 - Pressure and leakage tests.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... adjacent cargo tanks empty and at atmospheric pressure. Each closure, except pressure relief devices and... 49 Transportation 3 2014-10-01 2014-10-01 false Pressure and leakage tests. 178.345-13 Section 178... Specifications for Containers for Motor Vehicle Transportation § 178.345-13 Pressure and leakage tests. (a)...

  16. 49 CFR 178.345-13 - Pressure and leakage tests.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... adjacent cargo tanks empty and at atmospheric pressure. Each closure, except pressure relief devices and... 49 Transportation 3 2013-10-01 2013-10-01 false Pressure and leakage tests. 178.345-13 Section 178... Specifications for Containers for Motor Vehicle Transportation § 178.345-13 Pressure and leakage tests. (a)...

  17. 49 CFR 178.345-13 - Pressure and leakage tests.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... adjacent cargo tanks empty and at atmospheric pressure. Each closure, except pressure relief devices and... 49 Transportation 3 2012-10-01 2012-10-01 false Pressure and leakage tests. 178.345-13 Section 178... Specifications for Containers for Motor Vehicle Transportation § 178.345-13 Pressure and leakage tests. (a)...

  18. A review of leakage flow in centrifugal blood pumps.

    PubMed

    Chan, Weng-Kong; Wong, Yew-Wah

    2006-05-01

    This article presents a new approach in determining the functional relationship between the leakage flow in a centrifugal blood pump and various parameters that affect it. While high leakage flow in a blood pump is essential for good washout and can help prevent thrombus formation, excessive leakage flow will result in higher fluid shear stress that may lead to hemolysis. Dimensional analysis is employed to provide a functional relationship between leakage flow rate and other important parameters governing the operation of a centrifugal blood pump. Results showed that pump performance with a smaller gap clearance is clearly superior compared to those of two other similar pumps with larger gap clearances. It was also observed that the nondimensional leakage flow rate varies almost linearly with dimensionless pump head. It also decreases with increasing volume flow rate. A smaller gap clearance will also increase the flow resistance and hence, decrease the nondimensional leakage flow rate. Increasing surface roughness, length of the gap clearance passage, or loss coefficient of the gap geometry will increase losses and hence, decrease the leakage flow rate. It is also interesting to note that for a given pump and gap clearance geometry, the nondimensional leakage flow rate is almost independent of the Reynolds number when specific speed is constant.

  19. 49 CFR 178.347-5 - Pressure and leakage test.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 3 2011-10-01 2011-10-01 false Pressure and leakage test. 178.347-5 Section 178... Specifications for Containers for Motor Vehicle Transportation § 178.347-5 Pressure and leakage test. (a) Each cargo tank must be tested in accordance with § 178.345-13 and this section. (b) Pressure test....

  20. 49 CFR 178.346-5 - Pressure and leakage tests.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 3 2014-10-01 2014-10-01 false Pressure and leakage tests. 178.346-5 Section 178... Specifications for Containers for Motor Vehicle Transportation § 178.346-5 Pressure and leakage tests. (a) Each cargo tank must be tested in accordance with § 178.345-13 and this section. (b) Pressure test....

  1. 49 CFR 178.348-5 - Pressure and leakage test.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 2 2010-10-01 2010-10-01 false Pressure and leakage test. 178.348-5 Section 178... PACKAGINGS Specifications for Containers for Motor Vehicle Transportation § 178.348-5 Pressure and leakage test. (a) Each cargo tank must be tested in accordance with § 178.345-13 and this section. (b)...

  2. 49 CFR 178.346-5 - Pressure and leakage tests.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 3 2012-10-01 2012-10-01 false Pressure and leakage tests. 178.346-5 Section 178... Specifications for Containers for Motor Vehicle Transportation § 178.346-5 Pressure and leakage tests. (a) Each cargo tank must be tested in accordance with § 178.345-13 and this section. (b) Pressure test....

  3. 49 CFR 178.346-5 - Pressure and leakage tests.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 3 2011-10-01 2011-10-01 false Pressure and leakage tests. 178.346-5 Section 178... Specifications for Containers for Motor Vehicle Transportation § 178.346-5 Pressure and leakage tests. (a) Each cargo tank must be tested in accordance with § 178.345-13 and this section. (b) Pressure test....

  4. 49 CFR 178.347-5 - Pressure and leakage test.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 2 2010-10-01 2010-10-01 false Pressure and leakage test. 178.347-5 Section 178... PACKAGINGS Specifications for Containers for Motor Vehicle Transportation § 178.347-5 Pressure and leakage test. (a) Each cargo tank must be tested in accordance with § 178.345-13 and this section. (b)...

  5. 49 CFR 178.348-5 - Pressure and leakage test.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 3 2012-10-01 2012-10-01 false Pressure and leakage test. 178.348-5 Section 178... Specifications for Containers for Motor Vehicle Transportation § 178.348-5 Pressure and leakage test. (a) Each cargo tank must be tested in accordance with § 178.345-13 and this section. (b) Pressure test....

  6. 49 CFR 178.347-5 - Pressure and leakage test.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 3 2014-10-01 2014-10-01 false Pressure and leakage test. 178.347-5 Section 178... Specifications for Containers for Motor Vehicle Transportation § 178.347-5 Pressure and leakage test. (a) Each cargo tank must be tested in accordance with § 178.345-13 and this section. (b) Pressure test....

  7. 49 CFR 178.347-5 - Pressure and leakage test.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 3 2013-10-01 2013-10-01 false Pressure and leakage test. 178.347-5 Section 178... Specifications for Containers for Motor Vehicle Transportation § 178.347-5 Pressure and leakage test. (a) Each cargo tank must be tested in accordance with § 178.345-13 and this section. (b) Pressure test....

  8. 49 CFR 178.348-5 - Pressure and leakage test.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 3 2013-10-01 2013-10-01 false Pressure and leakage test. 178.348-5 Section 178... Specifications for Containers for Motor Vehicle Transportation § 178.348-5 Pressure and leakage test. (a) Each cargo tank must be tested in accordance with § 178.345-13 and this section. (b) Pressure test....

  9. 49 CFR 178.347-5 - Pressure and leakage test.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 3 2012-10-01 2012-10-01 false Pressure and leakage test. 178.347-5 Section 178... Specifications for Containers for Motor Vehicle Transportation § 178.347-5 Pressure and leakage test. (a) Each cargo tank must be tested in accordance with § 178.345-13 and this section. (b) Pressure test....

  10. 49 CFR 178.346-5 - Pressure and leakage tests.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 3 2013-10-01 2013-10-01 false Pressure and leakage tests. 178.346-5 Section 178... Specifications for Containers for Motor Vehicle Transportation § 178.346-5 Pressure and leakage tests. (a) Each cargo tank must be tested in accordance with § 178.345-13 and this section. (b) Pressure test....

  11. 49 CFR 178.348-5 - Pressure and leakage test.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 3 2011-10-01 2011-10-01 false Pressure and leakage test. 178.348-5 Section 178... Specifications for Containers for Motor Vehicle Transportation § 178.348-5 Pressure and leakage test. (a) Each cargo tank must be tested in accordance with § 178.345-13 and this section. (b) Pressure test....

  12. 49 CFR 178.348-5 - Pressure and leakage test.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 3 2014-10-01 2014-10-01 false Pressure and leakage test. 178.348-5 Section 178... Specifications for Containers for Motor Vehicle Transportation § 178.348-5 Pressure and leakage test. (a) Each cargo tank must be tested in accordance with § 178.345-13 and this section. (b) Pressure test....

  13. 49 CFR 178.346-5 - Pressure and leakage tests.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 2 2010-10-01 2010-10-01 false Pressure and leakage tests. 178.346-5 Section 178... PACKAGINGS Specifications for Containers for Motor Vehicle Transportation § 178.346-5 Pressure and leakage tests. (a) Each cargo tank must be tested in accordance with § 178.345-13 and this section. (b)...

  14. 40 CFR 90.324 - Analyzer leakage check.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... Provisions § 90.324 Analyzer leakage check. (a) Vacuum side leak check. (1) Check any location within the analysis system where a vacuum leak could affect the test results. (2) The maximum allowable leakage rate on the vacuum side is 0.5 percent of the in-use flow rate for the portion of the system being...

  15. 40 CFR 90.324 - Analyzer leakage check.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... Provisions § 90.324 Analyzer leakage check. (a) Vacuum side leak check. (1) Check any location within the analysis system where a vacuum leak could affect the test results. (2) The maximum allowable leakage rate on the vacuum side is 0.5 percent of the in-use flow rate for the portion of the system being...

  16. 40 CFR 90.324 - Analyzer leakage check.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... Provisions § 90.324 Analyzer leakage check. (a) Vacuum side leak check. (1) Check any location within the analysis system where a vacuum leak could affect the test results. (2) The maximum allowable leakage rate on the vacuum side is 0.5 percent of the in-use flow rate for the portion of the system being...

  17. 40 CFR 90.324 - Analyzer leakage check.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... Provisions § 90.324 Analyzer leakage check. (a) Vacuum side leak check. (1) Check any location within the analysis system where a vacuum leak could affect the test results. (2) The maximum allowable leakage rate on the vacuum side is 0.5 percent of the in-use flow rate for the portion of the system being...

  18. 40 CFR 89.316 - Analyzer leakage and response time.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... Equipment Provisions § 89.316 Analyzer leakage and response time. (a) Vacuum side leak check. (1) Any location within the analysis system where a vacuum leak could affect the test results must be checked. (2) The maximum allowable leakage rate on the vacuum side is 0.5 percent of the in-use flow rate for...

  19. 40 CFR 90.324 - Analyzer leakage check.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... Provisions § 90.324 Analyzer leakage check. (a) Vacuum side leak check. (1) Check any location within the analysis system where a vacuum leak could affect the test results. (2) The maximum allowable leakage rate on the vacuum side is 0.5 percent of the in-use flow rate for the portion of the system being...

  20. A CONCEPTUAL UNDERSTANDING OF LEAKAGE DURING SOIL-GAS SAMPLING

    EPA Science Inventory

    A heuristic model is developed to develop a conceptual understanding of leakage during soil-gas sampling. Leakage is shown to be simply a function of the permeability contrast between the formation and borehole and geometric factors. As the ratio of formation to borehole permea...

  1. 40 CFR 265.222 - Action leakage rate.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... to § 265.221(a). The action leakage rate is the maximum design flow rate that the leak detection... proposed response actions (e.g., the action leakage rate must consider decreases in the flow capacity of... exceeded, the owner or operator must convert the weekly or monthly flow rate from the monitoring...

  2. 40 CFR 264.302 - Action leakage rate.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... landfill units subject to § 264.301(c) or (d). The action leakage rate is the maximum design flow rate that... action leakage rate has been exceeded, the owner or operator must convert the weekly or monthly flow rate from the monitoring data obtained under § 264.303(c) to an average daily flow rate (gallons per...

  3. Questioning the social intelligence hypothesis.

    PubMed

    Holekamp, Kay E

    2007-02-01

    The social intelligence hypothesis posits that complex cognition and enlarged "executive brains" evolved in response to challenges that are associated with social complexity. This hypothesis has been well supported, but some recent data are inconsistent with its predictions. It is becoming increasingly clear that multiple selective agents, and non-selective constraints, must have acted to shape cognitive abilities in humans and other animals. The task now is to develop a larger theoretical framework that takes into account both inter-specific differences and similarities in cognition. This new framework should facilitate consideration of how selection pressures that are associated with sociality interact with those that are imposed by non-social forms of environmental complexity, and how both types of functional demands interact with phylogenetic and developmental constraints.

  4. Metabolic hypothesis for human altriciality.

    PubMed

    Dunsworth, Holly M; Warrener, Anna G; Deacon, Terrence; Ellison, Peter T; Pontzer, Herman

    2012-09-18

    The classic anthropological hypothesis known as the "obstetrical dilemma" is a well-known explanation for human altriciality, a condition that has significant implications for human social and behavioral evolution. The hypothesis holds that antagonistic selection for a large neonatal brain and a narrow, bipedal-adapted birth canal poses a problem for childbirth; the hominin "solution" is to truncate gestation, resulting in an altricial neonate. This explanation for human altriciality based on pelvic constraints persists despite data linking human life history to that of other species. Here, we present evidence that challenges the importance of pelvic morphology and mechanics in the evolution of human gestation and altriciality. Instead, our analyses suggest that limits to maternal metabolism are the primary constraints on human gestation length and fetal growth. Although pelvic remodeling and encephalization during hominin evolution contributed to the present parturitional difficulty, there is little evidence that pelvic constraints have altered the timing of birth.

  5. Endoscopic Treatment of Stump Leakage Related to the Ileal Conduit

    PubMed Central

    Odemis, Bulent; Oztas, Erkin; Akpinar, Muhammet Yener; Olcucuoglu, Erkan; Kayacetin, Ertugrul

    2016-01-01

    Abstract Background: Ileal conduit with leakage from either the anastomotic site or the stump is associated with high morbidity and mortality rates. The standard treatment of stump leakage is surgery. Case Presentation: A 60-year-old male patient was admitted to our hospital with complaint of hematuria and bladder carcinoma was diagnosed. After performing radical cystectomy and ileal conduit, he developed fever with abdominal pain within the first week of surgery. Stump leakage was diagnosed by endoscopic examination performed through a gastroscope. After two over-the-scope clips (OTSCs) were applied to the stump, vinyl mesh was inserted into the space between the OTSCs. Later, cyanoacrylat and lipiodol were repelled on the OTSCs and vinyl mesh. Subsequently, stump leakage was resolved. Conclusion: This is the first case of stump leakage related to ileal conduit that has been treated endoscopically, according to the current literature. PMID:27579432

  6. Quantum Speed Limits for Leakage and Decoherence

    NASA Astrophysics Data System (ADS)

    Marvian, Iman; Lidar, Daniel A.

    2015-11-01

    We introduce state-independent, nonperturbative Hamiltonian quantum speed limits for population leakage and fidelity loss, for a gapped open system interacting with a reservoir. These results hold in the presence of initial correlations between the system and the reservoir, under the sole assumption that their interaction and its commutator with the reservoir Hamiltonian are norm bounded. The reservoir need not be thermal and can be time dependent. We study the significance of energy mismatch between the system and the local degrees of freedom of the reservoir that directly interact with the system. We demonstrate that, in general, by increasing the system gap we may reduce this energy mismatch, and, consequently, drive the system and the reservoir into resonance; this can accelerate fidelity loss, irrespective of the thermal properties or state of the reservoir. This implies that quantum error suppression strategies based on increasing the gap are not uniformly beneficial. Our speed limits also yield an elementary lower bound on the relaxation time of spin systems.

  7. A Molecular–Structure Hypothesis

    PubMed Central

    Boeyens, Jan C. A.

    2010-01-01

    The self-similar symmetry that occurs between atomic nuclei, biological growth structures, the solar system, globular clusters and spiral galaxies suggests that a similar pattern should characterize atomic and molecular structures. This possibility is explored in terms of the current molecular structure-hypothesis and its extension into four-dimensional space-time. It is concluded that a quantum molecule only has structure in four dimensions and that classical (Newtonian) structure, which occurs in three dimensions, cannot be simulated by quantum-chemical computation. PMID:21151437

  8. In search of the hypothesis.

    PubMed Central

    Kaufman, J S; Cooper, R S

    1995-01-01

    Epidemiologic studies of racial differences sorely lack sound and explicit hypotheses. Race is a social convention, not a biological concept. Its careless use in epidemiology demonstrates a failure to generate appropriate hypotheses to study its role in health. Studies of hypertension in blacks illustrate the point. Two underlying pitfalls plague hypothesis generation: directionality involving the null and alternative hypotheses and circularity, where efforts to understand social factors have the effect of emphasizing racial differences. The proper prescription is to identify explicitly the hypotheses of interest, including their origins and implication. Images p662-a p665-a PMID:8570813

  9. Leakage assessment and identification of fluid leakage scenarios at CO2 storage sites (Invited)

    NASA Astrophysics Data System (ADS)

    Bunz, S.

    2013-12-01

    One of the major objectives of the ECO2 project (EU FP7) is to assess the risks associated with the storage of CO2 below the seabed. Within this frame, work package (WP) 1 investigates the sedimentary cover at currently active and potential storage sites using novel geophysical baseline studies, monitoring and modeling techniques in order to better understand CO2 migration mechanisms and its spatial and temporal evolution. A proper risk assessment of CO2 storage hinges on a thorough understanding of the geological evolution of an area and a sound comprehension of subsurface anomalies associated with the flow of fluids and their governing geological controls. To this end, WP 1 has analyzed a wealth of seafloor imaging and seismic data from the industrial storage sites at Sleipner and Snøhvit on the Norwegian Margin. In addition to conventional seafloor and seismic data, several novel high-resolution acquisition technologies have been used during offshore expeditions in 2011 and 2012, and their data integrated into this study. A solid background on the geological development and the stratigraphic framework has been developed including an interpretation of subsurface structure and structures related to the presence of fluids and possible fluid pathways on the basis of conventional 3D seismic data and by integrating several additional high-resolution data sets. The data revealed a number of fluid-flow features, as for example gas chimneys, pipes, shallow gas accumulations, leaking faults, fractures along the seafloor as well as gas hydrates. Each of these structures or set of structures has been evaluated with respect to their occurrence, distribution, origin and as a means for providing a potential pathway for CO2 if it would leak out of the storage formation. On the basis of this evaluation and the assumptions that paleo fluid-flow structures may be reactivated by CO2 injection and that the caprock of the storage formation may breach, a number of potential leakage

  10. Hypothesis tests for hydrologic alteration

    NASA Astrophysics Data System (ADS)

    Kroll, Charles N.; Croteau, Kelly E.; Vogel, Richard M.

    2015-11-01

    Hydrologic systems can be altered by anthropogenic and climatic influences. While there are a number of statistical frameworks for describing and evaluating the extent of hydrologic alteration, here we present a new framework for assessing whether statistically significant hydrologic alteration has occurred, or whether the shift in the hydrologic regime is consistent with the natural variability of the system. Four hypothesis tests based on shifts of flow duration curves (FDCs) are developed and tested using three different experimental designs based on different strategies for resampling of annual FDCs. The four hypothesis tests examined are the Kolmogorov-Smirnov (KS), Kuiper (K), confidence interval (CI), and ecosurplus and ecodeficit (Eco). Here 117 streamflow sites that have potentially undergone hydrologic alteration due to reservoir construction are examined. 20 years of pre-reservoir record is used to develop the critical value of the test statistic for type I errors of 5% and 10%, while 10 years of post-alteration record is used to examine the power of each test. The best experimental design, based on calculating the mean annual FDC from an exhaustive jackknife resampling regime, provided a larger number of unique values of each test statistic and properly reproduced type I errors. Of the four tests, the CI test consistently had the highest power, while the K test had the second highest power; KS and Eco always had the lowest power. The power of the CI test appeared related to the storage ratio of the reservoir, a rough measure of the hydrologic alteration of the system.

  11. Hypothesis testing and earthquake prediction.

    PubMed

    Jackson, D D

    1996-04-30

    Requirements for testing include advance specification of the conditional rate density (probability per unit time, area, and magnitude) or, alternatively, probabilities for specified intervals of time, space, and magnitude. Here I consider testing fully specified hypotheses, with no parameter adjustments or arbitrary decisions allowed during the test period. Because it may take decades to validate prediction methods, it is worthwhile to formulate testable hypotheses carefully in advance. Earthquake prediction generally implies that the probability will be temporarily higher than normal. Such a statement requires knowledge of "normal behavior"--that is, it requires a null hypothesis. Hypotheses can be tested in three ways: (i) by comparing the number of actual earth-quakes to the number predicted, (ii) by comparing the likelihood score of actual earthquakes to the predicted distribution, and (iii) by comparing the likelihood ratio to that of a null hypothesis. The first two tests are purely self-consistency tests, while the third is a direct comparison of two hypotheses. Predictions made without a statement of probability are very difficult to test, and any test must be based on the ratio of earthquakes in and out of the forecast regions.

  12. The hydraulic limitation hypothesis revisited.

    PubMed

    Ryan, Michael G; Phillips, Nathan; Bond, Barbara J

    2006-03-01

    We proposed the hydraulic limitation hypothesis (HLH) as a mechanism to explain universal patterns in tree height, and tree and stand biomass growth: height growth slows down as trees grow taller, maximum height is lower for trees of the same species on resource-poor sites and annual wood production declines after canopy closure for even-aged forests. Our review of 51 studies that measured one or more of the components necessary for testing the hypothesis showed that taller trees differ physiologically from shorter, younger trees. Stomatal conductance to water vapour (g(s)), photosynthesis (A) and leaf-specific hydraulic conductance (K L) are often, but not always, lower in taller trees. Additionally, leaf mass per area is often greater in taller trees, and leaf area:sapwood area ratio changes with tree height. We conclude that hydraulic limitation of gas exchange with increasing tree size is common, but not universal. Where hydraulic limitations to A do occur, no evidence supports the original expectation that hydraulic limitation of carbon assimilation is sufficient to explain observed declines in wood production. Any limit to height or height growth does not appear to be related to the so-called age-related decline in wood production of forests after canopy closure. Future work on this problem should explicitly link leaf or canopy gas exchange with tree and stand growth, and consider a more fundamental assumption: whether tree biomass growth is limited by carbon availability.

  13. Atlantic multi-decadal oscillation covaries with Agulhas leakage

    PubMed Central

    Biastoch, Arne; Durgadoo, Jonathan V.; Morrison, Adele K.; van Sebille, Erik; Weijer, Wilbert; Griffies, Stephen M.

    2015-01-01

    The interoceanic transfer of seawater between the Indian Ocean and the Atlantic, ‘Agulhas leakage', forms a choke point for the overturning circulation in the global ocean. Here, by combining output from a series of high-resolution ocean and climate models with in situ and satellite observations, we construct a time series of Agulhas leakage for the period 1870–2014. The time series demonstrates the impact of Southern Hemisphere westerlies on decadal timescales. Agulhas leakage shows a correlation with the Atlantic Multi-decadal Oscillation on multi-decadal timescales; the former leading by 15 years. This is relevant for climate in the North Atlantic. PMID:26656850

  14. Atlantic multi-decadal oscillation covaries with Agulhas leakage.

    PubMed

    Biastoch, Arne; Durgadoo, Jonathan V; Morrison, Adele K; van Sebille, Erik; Weijer, Wilbert; Griffies, Stephen M

    2015-12-10

    The interoceanic transfer of seawater between the Indian Ocean and the Atlantic, 'Agulhas leakage', forms a choke point for the overturning circulation in the global ocean. Here, by combining output from a series of high-resolution ocean and climate models with in situ and satellite observations, we construct a time series of Agulhas leakage for the period 1870-2014. The time series demonstrates the impact of Southern Hemisphere westerlies on decadal timescales. Agulhas leakage shows a correlation with the Atlantic Multi-decadal Oscillation on multi-decadal timescales; the former leading by 15 years. This is relevant for climate in the North Atlantic.

  15. Theory and Application of Magnetic Flux Leakage Pipeline Detection.

    PubMed

    Shi, Yan; Zhang, Chao; Li, Rui; Cai, Maolin; Jia, Guanwei

    2015-12-10

    Magnetic flux leakage (MFL) detection is one of the most popular methods of pipeline inspection. It is a nondestructive testing technique which uses magnetic sensitive sensors to detect the magnetic leakage field of defects on both the internal and external surfaces of pipelines. This paper introduces the main principles, measurement and processing of MFL data. As the key point of a quantitative analysis of MFL detection, the identification of the leakage magnetic signal is also discussed. In addition, the advantages and disadvantages of different identification methods are analyzed. Then the paper briefly introduces the expert systems used. At the end of this paper, future developments in pipeline MFL detection are predicted.

  16. Theory and Application of Magnetic Flux Leakage Pipeline Detection

    PubMed Central

    Shi, Yan; Zhang, Chao; Li, Rui; Cai, Maolin; Jia, Guanwei

    2015-01-01

    Magnetic flux leakage (MFL) detection is one of the most popular methods of pipeline inspection. It is a nondestructive testing technique which uses magnetic sensitive sensors to detect the magnetic leakage field of defects on both the internal and external surfaces of pipelines. This paper introduces the main principles, measurement and processing of MFL data. As the key point of a quantitative analysis of MFL detection, the identification of the leakage magnetic signal is also discussed. In addition, the advantages and disadvantages of different identification methods are analyzed. Then the paper briefly introduces the expert systems used. At the end of this paper, future developments in pipeline MFL detection are predicted. PMID:26690435

  17. [Temporal dimensions of suicide: hypothesis].

    PubMed

    Carbonell-Camós, Eliseu

    2008-01-01

    In this article, the author examines the temporal dimensions of suicide by taking into account the multiple existing approaches-circadian physiology, psychiatric or sociological epidemiology of suicide-however promoting a socio-anthropological perspective. From this perspective, suicide is examined as a social phenomenon inscribed in time. By beginning with a concern that is characteristic of anthropology of time, knowingly the relation between time of nature and time of society, the author addresses a key issue of the study of suicide already elaborated by Durkheim, in the relation between change that is a basic expression of the passage of time and suicide. After presenting different scientific contributions on the subject, the author proposes an hypothesis allowing integration of the influence of time related to natural phenomenon (cosmobiological rhythms) and the relation of time to social phenomenon (politico-economic rhythms) in relation with suicide and this, according to Gabennesch's theory of "failed promises."

  18. The Flexibility Hypothesis of Healing.

    PubMed

    Hinton, Devon E; Kirmayer, Laurence J

    2017-03-01

    Theories of healing have attempted to identify general mechanisms that may work across different modalities. These include altering expectations, remoralization, and instilling hope. In this paper, we argue that many forms of healing and psychotherapy may work by inducing positive psychological states marked by flexibility or an enhanced ability to shift cognitive sets. Healing practices may induce these states of cognitive and emotional flexibility through specific symbolic interventions we term "flexibility primers" that can include images, metaphors, music, and other media. The flexibility hypothesis suggests that cognitive and emotional flexibility is represented, elicited, and enacted through multiple modalities in healing rituals. Identifying psychological processes and cultural forms that evoke and support cognitive and emotional flexibility provides a way to understand the cultural specificity and potential efficacy of particular healing practices and can guide the design of interventions that promote resilience and well-being.

  19. Results of microwave oven radiation leakage surveys at Fermilab

    SciTech Connect

    Miller, T.M.

    1987-01-01

    This report describes the results of routine microwave oven leakage surveys which were conducted at Fermi National Accelerator Laboratory (Fermilab) between 1974 and 1985. A total of 80 ovens representing 250 oven-years of operation were examined. The mean maximum leakage at any point 5 cm from the surface was 0.20 x/ 3.1 mW/cm/sup 2/. Although there was a great deal of scatter in sequential measurements for individual ovens, it appears that leakage tends to increase with oven age. The mean logarithmic rate of increase for the 55 ovens with usable data was 0.21 per year. Case histories of ovens leaking in excess of the standard were examined, and improvements in leakage monitoring programs are suggested.

  20. Cement Leakage into Adjacent Vertebral Body Following Percutaneous Vertebroplasty.

    PubMed

    Park, Jae Hoo; Kim, Hyeun Sung; Kim, Seok Won

    2016-06-01

    Percutaneous vertebroplasty (PV) is a minimally invasive procedure for osteoporotic vertebral compression fractures that fail to respond to conventional conservative treatment. It significantly improves intolerable back pain within hours, and has a low complication rate. Although rare, PV is not free of complications, most of which are directly related to cement leakage. Because of its association with new adjacent fracture, the importance of cement leakage into the adjacent disc space is paramount. Here, we report an interesting case of cement leakage into the adjacent upper vertebral body as well as disc space following PV. To the best of our knowledge, there has been no report of cement leakage into the adjacent vertebral body following PV. This rare case is presented along with a review of the literature.

  1. [A serious complication in colorectal surgery: anastomotic leakage. Our experience].

    PubMed

    Petitti, T; Lippolis, G; Ferrozzi, L

    2005-10-01

    Anastomotic leakage is a severe complication in colorectal surgery with a lot of generic and specific risk factors. There are still controversies about the possibility to prevent it or to limit its severity with the use of faecal diversions. We report our experience on 189 patients operated in five years on colon-rectum, in election and emergency, with manual or mechanical anastomoses in the last 20 cm from the anal verge. We have had 21 anastomotic leakages (11%), symptomatic in 10 cases (5.5%), and 5 deaths (2.6%), 3 directly correlated to the leakage. In the patients (n 98) with loop-ileostomy there wasn't anastomotic leakages reduction, but only of clinical impact. We prefer loop-ileostomy in cases of extraperitoneal anastomoses, always in emergency and in anastomoses at risk.

  2. Expedient methods of respiratory protection. II. Leakage tests. Final report

    SciTech Connect

    Cooper, D.W.; Hinds, W.C.; Price, J.M.; Weker, R.; Yee, H.S.

    1983-07-01

    The following readily-available materials were tested on a manikin connected to a breathing simulator to determine the fraction of an approximately 2-..mu..m-diameter aerosol that would leak around the seal of the materials to the manikin's face: cotton/polyester shirt material, cotton handkerchief material, toweling (a wash cloth), a surgical mask (Johnson and Johnson Co., model HRI 8137), and a NIOSH-approved disposable face mask (3M, model number 8710). The leakage tests were performed to supplement the measurements of penetration through the materials, conducted as the first phase of this investigation. The leakage tests were performed with the materials held on to the face by three methods, leakage fractions being determined from comparisons with the penetration of the same aerosol for the materials fully taped to the face. At a breathing rate of 37 liters per minute, mean leakages ranged from 0.0 percent to 63 percent. Mean penetrations exclusive of leakage ranged from 0.6 percent to 39 percent. Use of nylon hosiery material (panty hose) to hold the handkerchief material or the disposable face mask to the face was found to be very effective in preventing leakage. Such a combination could be expected to reduce leakage around the handkerchief to about ten percent or less in practice, and around the mask to less than one percent, offering substantial protection from accidentally generated aerosols. The reduction in leakage around the mask provided by the hosiery material suggests the adaptation and use of such an approach in regular industrial hygiene practice. The third and final phase of this investigation is underway, in which the penetration of the materials by particles with diameters between 0.05 and 0.5 ..mu..m is being measured and the effectiveness of the methods for dose reduction in the presence of radioactive aerosols is being modeled.

  3. Air leakage on the postoperative day: powerful factor of postoperative recurrence after thoracoscopic bullectomy

    PubMed Central

    Jeon, Hyun Woo; Kye, Yeo Kon; Kim, Kyung Soo

    2016-01-01

    Background Primary spontaneous pneumothorax (PSP) is a relatively common disorder in young patients. Although various surgical techniques have been introduced, recurrence after video-assisted thoracoscopic surgery (VATS) remains high. The aim of study was to identify the risk factors for postoperative recurrence after thoracoscopic bullectomy in the spontaneous pneumothorax. Methods From January 2011 through March 2013, two hundreds and thirty two patients underwent surgery because of pneumothorax. Patients with a secondary pneumothorax, as well as cases of single port surgery, an open procedure, additional pleural procedure (pleurectomy, pleural abrasion) or lack of medical records were excluded. The records of 147 patients with PSP undergoing 3-port video-assisted thoracoscopic bullectomy with staple line coverage using an absorbable polyglycolic acid (PGA) sheet were retrospectively reviewed. Results The median age was 19 years (range, 11−34 years) with male predominance (87.8%). Median postoperative hospital stay was 3 days (range, 1−10 days) without mortality. Complications were developed in five patients. A total of 24 patients showed postoperative recurrence (16.3%). Younger age less than 17 years old and immediate postoperative air leakage were risk factors for postoperative recurrence after thoracoscopic bullectomy by multivariate analysis. Conclusions Immediate postoperative air leakage was the risk factor for postoperative recurrence. However, further study will be required for the correlation of air leakage with recurrence. PMID:26904217

  4. Defect-Enabled Electrical Current Leakage in Ultraviolet Light-Emitting Diodes

    DOE PAGES

    Moseley, Michael William; Allerman, Andrew A.; Crawford, Mary H.; ...

    2015-04-13

    The AlGaN materials system offers a tunable, ultra-wide bandgap that is exceptionally useful for high-power electronics and deep ultraviolet optoelectronics. Moseley et al. (pp. 723–726) investigate a structural defect known as an open-core threading dislocation or ''nanopipe'' that is particularly detrimental to devices that employ these materials. Furthermore, an AlGaN thin film was synthesized using metal-organic chemical-vapor deposition. Electrical current leakage is detected at a discrete point using a conductive atomic-force microscope (CAFM). However, no physical feature or abnormality at this location was visible by an optical microscope. The AlGaN thin film was then etched in hot phosphoric acid, andmore » the same location that was previously analyzed was revisited with the CAFM. The point that previously exhibited electrical current leakage had been decorated with a 1.1 μm wide hexagonal pit, which identified the site of electrical current leakage as a nanopipe and allows these defects to be easily observed by optical microscopy. Moreover, with this nanopipe identification and quantification strategy, the authors were able to correlate decreasing ultraviolet light-emitting diode optical output power with increasing nanopipe density.« less

  5. Defect-Enabled Electrical Current Leakage in Ultraviolet Light-Emitting Diodes

    SciTech Connect

    Moseley, Michael William; Allerman, Andrew A.; Crawford, Mary H.; Wierer, Jonathan; Smith, Michael L.; Biedermann, Laura

    2015-04-13

    The AlGaN materials system offers a tunable, ultra-wide bandgap that is exceptionally useful for high-power electronics and deep ultraviolet optoelectronics. Moseley et al. (pp. 723–726) investigate a structural defect known as an open-core threading dislocation or ''nanopipe'' that is particularly detrimental to devices that employ these materials. Furthermore, an AlGaN thin film was synthesized using metal-organic chemical-vapor deposition. Electrical current leakage is detected at a discrete point using a conductive atomic-force microscope (CAFM). However, no physical feature or abnormality at this location was visible by an optical microscope. The AlGaN thin film was then etched in hot phosphoric acid, and the same location that was previously analyzed was revisited with the CAFM. The point that previously exhibited electrical current leakage had been decorated with a 1.1 μm wide hexagonal pit, which identified the site of electrical current leakage as a nanopipe and allows these defects to be easily observed by optical microscopy. Moreover, with this nanopipe identification and quantification strategy, the authors were able to correlate decreasing ultraviolet light-emitting diode optical output power with increasing nanopipe density.

  6. Energy Efficient High-Pressure Turbine Leakage Technology Report

    NASA Technical Reports Server (NTRS)

    Gardner, W. B.

    1980-01-01

    The leakage test program was one of such supporting technology programs structured to provide guidance to the Energy Efficient Engine High Pressure Turbine Component Design Effort. Leakage reduction techniques were identified and evaluated. Test models were used to simulate component leak paths and to evaluate leakage reduction techniques. These models simulated the blade/disk attachment, the vane inner platform attachment, and the vane outer platform attachment combined with the blade outer airseal. Disk blade attachment testing indicated that leakage in this area could be reduced to very low levels by paying careful attention to the tolerances along the contact surface between the blade vibration damper and the blade platform contact surface. The aim of feather seal testing was to achieve a goal for an effective leakage gap of one mil (.001 inch) per inch of feather seal length. Results indicated that effective gaps even below the goal level were achievable by (1) maintaining close tolerances between feather seals and their slots to minimize end gaps and limit seal rotation, (2) avoiding feather seal overlap, and (3) minimizing feather seal intersections. W seals were shown to be effective leakage control devices. Wire rope, in its present state of development, was shown not to be an effective sealing concept for application to the component design.

  7. Subtotal petrosectomy and cerebrospinal fluid leakage in unilateral anacusis.

    PubMed

    Magliulo, Giuseppe; Iannella, Giannicola; Ciniglio Appiani, Mario; Re, Massimo

    2014-12-01

    Objective This study presents a group of patients experiencing recurrent cerebrospinal fluid (CSF) leakage associated with ipsilateral anacusis who underwent subtotal petrosectomies with the goal of stopping the CSF leak and preventing meningitis. Materials and Methods Eight patients with CSF leakage were enrolled: three patients with giant vestibular schwannomas had CSF leakage after gamma knife failure and subsequent removal via a retrosigmoid approach; two patients had malformations at the level of the inner ear with consequent translabyrinthine fistulas; two had posttraumatic CSF leakages; and one had a CSF leakage coexisting with an encephalocele. Two patients developed meningitis that resolved with antibiotic therapy. Each patient had preoperative anacusis and vestibular nerve areflexia on the affected side. Results The patients with congenital or posttraumatic CSF leaks had undergone at least one unsuccessful endaural approach to treat the fistula. All eight patients were treated successfully with a subtotal petrosectomy. The symptoms disappeared within 2 months postoperatively. No meningitis, signs of fistula, or other symptoms occurred during the follow-up. Conclusion A subtotal petrosectomy should be the first choice of treatment in patients with recurrent CSF leakage whenever there is associated unilateral anacusis.

  8. Subtotal Petrosectomy and Cerebrospinal Fluid Leakage in Unilateral Anacusis

    PubMed Central

    Magliulo, Giuseppe; Iannella, Giannicola; Appiani, Mario Ciniglio; Re, Massimo

    2014-01-01

    Objective This study presents a group of patients experiencing recurrent cerebrospinal fluid (CSF) leakage associated with ipsilateral anacusis who underwent subtotal petrosectomies with the goal of stopping the CSF leak and preventing meningitis. Materials and Methods Eight patients with CSF leakage were enrolled: three patients with giant vestibular schwannomas had CSF leakage after gamma knife failure and subsequent removal via a retrosigmoid approach; two patients had malformations at the level of the inner ear with consequent translabyrinthine fistulas; two had posttraumatic CSF leakages; and one had a CSF leakage coexisting with an encephalocele. Two patients developed meningitis that resolved with antibiotic therapy. Each patient had preoperative anacusis and vestibular nerve areflexia on the affected side. Results The patients with congenital or posttraumatic CSF leaks had undergone at least one unsuccessful endaural approach to treat the fistula. All eight patients were treated successfully with a subtotal petrosectomy. The symptoms disappeared within 2 months postoperatively. No meningitis, signs of fistula, or other symptoms occurred during the follow-up. Conclusion A subtotal petrosectomy should be the first choice of treatment in patients with recurrent CSF leakage whenever there is associated unilateral anacusis. PMID:25452896

  9. Prediction of leakage flow in a shrouded centrifugal blood pump.

    PubMed

    Teo, Ji-Bin; Chan, Weng-Kong; Wong, Yew-Wah

    2010-09-01

    This article proposes a phenomenological model to predict the leakage flow in the clearance gap of shrouded centrifugal blood pumps. A good washout in the gap clearance between the rotating impeller surfaces and volute casing is essential to avoid thrombosis. However, excessive leakage flow will result in higher fluid shear stress that may lead to hemolysis. Computational fluid dynamics (CFD) analysis was performed to investigate the leakage flow in a miniaturized shrouded centrifugal blood pump operating at a speed of 2000 rpm. Based on an analytical model derived earlier, a phenomenological model is proposed to predict the leakage flow. The leakage flow rate is found to be proportional to h(α) , where h is the gap size and the exponent α ranges from 2.955 to 3.15 for corresponding gap sizes of 0.2-0.5 mm. In addition, it is observed that α is a linear function of the gap size h. The exponent α compensates for the variation of pressure difference along the circumferential direction as well as inertia effects that are dominant for larger gap clearances. The proposed model displays good agreement with computational results. The CFD analysis also showed that for larger gap sizes, the total leakage flow rate is of the same order of magnitude as the operating flow rate, thus suggesting low volumetric efficiency.

  10. Field size dependent mapping of medical linear accelerator radiation leakage

    NASA Astrophysics Data System (ADS)

    Vũ Bezin, Jérémi; Veres, Attila; Lefkopoulos, Dimitri; Chavaudra, Jean; Deutsch, Eric; de Vathaire, Florent; Diallo, Ibrahima

    2015-03-01

    The purpose of this study was to investigate the suitability of a graphics library based model for the assessment of linear accelerator radiation leakage. Transmission through the shielding elements was evaluated using the build-up factor corrected exponential attenuation law and the contribution from the electron guide was estimated using the approximation of a linear isotropic radioactive source. Model parameters were estimated by a fitting series of thermoluminescent dosimeter leakage measurements, achieved up to 100 cm from the beam central axis along three directions. The distribution of leakage data at the patient plane reflected the architecture of the shielding elements. Thus, the maximum leakage dose was found under the collimator when only one jaw shielded the primary beam and was about 0.08% of the dose at isocentre. Overall, we observe that the main contributor to leakage dose according to our model was the electron beam guide. Concerning the discrepancies between the measurements used to calibrate the model and the calculations from the model, the average difference was about 7%. Finally, graphics library modelling is a readily and suitable way to estimate leakage dose distribution on a personal computer. Such data could be useful for dosimetric evaluations in late effect studies.

  11. Repositioning of charged I-II loop amino acid residues within the electric field by beta subunit as a novel working hypothesis for the control of fast P/Q calcium channel inactivation.

    PubMed

    Sandoz, Guillaume; Lopez-Gonzalez, Ignacio; Stamboulian, Séverine; Weiss, Norbert; Arnoult, Christophe; De Waard, Michel

    2004-04-01

    We have investigated the contribution of the Ca(v)beta subunits to the process of inactivation dependent of the I-II loop of Ca(v)alpha(2.1). Two amino acid residues located in the alpha1 interaction domain (AID) of the I-II loop of Ca(v)alpha(2.1) (Arg(387) and Glu(388)) have been directly implicated in voltage-dependent inactivation of this channel. Various point mutations of these residues disrupt the interaction between the I-II loop and the III-IV loop, and thereby modify the inactivation properties of the channel by accelerating its kinetics and shifting the steady-state inactivation curve towards hyperpolarized potentials. A similar disruption is produced by Ca(v)beta(4) subunit association with the I-II loop. Moreover, in the presence of Ca(v)beta(4) subunit, introducing negatively charged residues at positions 387 or 388 slows inactivation kinetics down, whereas introducing positive charges has the opposite effect. The shift of the steady-state inactivation curve is also amino acid charge-dependent. In contrast, mutation of Arg(387) or Glu(388) does not alter the differential regulation of the different Ca(v)beta isoforms on inactivation. These results suggest that the expression of Ca(v)beta(4) alters the contribution of charged residues at positions 387 and 388 to inactivation. We discuss these results with regard to the actual hypotheses on the mechanisms of calcium channel inactivation. We introduce the working concept that Ca(v)beta-subunits produce a conformational repositioning of charged AID residues within the electric field.

  12. THERMAL REGAIN FROM DISPLACEMENT OF DUCT LEAKAGE WITHIN INSULATION.

    SciTech Connect

    ANDREWS,J.W.

    2002-05-01

    In one type of duct efficiency retrofit, additional insulation is added to a duct system that is already insulated. For example, a layer of R-4 insulation might be: added to a duct system that already has R-4 installed. It is possible that--either by chance or by design--the add-on layer, while not stopping duct leaks, might cause the leakage air to flow longitudinally for a distance, parallel to the duct, before it finds a way out of the newly added outer layer. This could happen by chance if the outer and inner layers of insulation have seams at different locations. Perhaps more usefully, if such longitudinal displacement of the leakage air turned out to be useful, it might be designed into the makeup of the outer insulation layer intended to be used in the retrofit. It is plausible that this leakage air might serve a useful function in keeping the insulation layer warmer (or, in the air-conditioning mode, cooler) than it would be in the absence of the leakage. By being held close to the ducts for a while, it might establish an artificially warmer (or cooler, in air conditioning) zone around the ducts. To the extent that this effect would reduce the heat losses from the ducts, the leakage should be credited with a ''thermal regain'' in the same way that leakage into buffer zones is credited with thermal regain when the leakage air warms (or cools) the buffer zone relative to the temperature it would have in the absence of such duct leakage. The purpose of this report is to investigate whether and to what extent such thermal regain exists. The model developed below applies to a situation where there are two distinct layers of insulation around the duct, with leakage air moving between them in a longitudinal direction for a distance before it finds its way out from the outer insulation layer. It may also apply approximately where there is a single insulation layer with an air barrier on the outside. Leakage air may pass into the insulation itself and thence

  13. The venom optimization hypothesis revisited.

    PubMed

    Morgenstern, David; King, Glenn F

    2013-03-01

    Animal venoms are complex chemical mixtures that typically contain hundreds of proteins and non-proteinaceous compounds, resulting in a potent weapon for prey immobilization and predator deterrence. However, because venoms are protein-rich, they come with a high metabolic price tag. The metabolic cost of venom is sufficiently high to result in secondary loss of venom whenever its use becomes non-essential to survival of the animal. The high metabolic cost of venom leads to the prediction that venomous animals may have evolved strategies for minimizing venom expenditure. Indeed, various behaviors have been identified that appear consistent with frugality of venom use. This has led to formulation of the "venom optimization hypothesis" (Wigger et al. (2002) Toxicon 40, 749-752), also known as "venom metering", which postulates that venom is metabolically expensive and therefore used frugally through behavioral control. Here, we review the available data concerning economy of venom use by animals with either ancient or more recently evolved venom systems. We conclude that the convergent nature of the evidence in multiple taxa strongly suggests the existence of evolutionary pressures favoring frugal use of venom. However, there remains an unresolved dichotomy between this economy of venom use and the lavish biochemical complexity of venom, which includes a high degree of functional redundancy. We discuss the evidence for biochemical optimization of venom as a means of resolving this conundrum.

  14. Alien abduction: a medical hypothesis.

    PubMed

    Forrest, David V

    2008-01-01

    In response to a new psychological study of persons who believe they have been abducted by space aliens that found that sleep paralysis, a history of being hypnotized, and preoccupation with the paranormal and extraterrestrial were predisposing experiences, I noted that many of the frequently reported particulars of the abduction experience bear more than a passing resemblance to medical-surgical procedures and propose that experience with these may also be contributory. There is the altered state of consciousness, uniformly colored figures with prominent eyes, in a high-tech room under a round bright saucerlike object; there is nakedness, pain and a loss of control while the body's boundaries are being probed; and yet the figures are thought benevolent. No medical-surgical history was apparently taken in the above mentioned study, but psychological laboratory work evaluated false memory formation. I discuss problems in assessing intraoperative awareness and ways in which the medical hypothesis could be elaborated and tested. If physicians are causing this syndrome in a percentage of patients, we should know about it; and persons who feel they have been abducted should be encouraged to inform their surgeons and anesthesiologists without challenging their beliefs.

  15. The Over-Pruning Hypothesis of Autism

    ERIC Educational Resources Information Center

    Thomas, Michael S. C.; Davis, Rachael; Karmiloff-Smith, Annette; Knowland, Victoria C. P.; Charman, Tony

    2016-01-01

    This article outlines the "over-pruning hypothesis" of autism. The hypothesis originates in a neurocomputational model of the regressive sub-type (Thomas, Knowland & Karmiloff-Smith, 2011a, 2011b). Here we develop a more general version of the over-pruning hypothesis to address heterogeneity in the timing of manifestation of ASD,…

  16. Involvement of ROCK-mediated endothelial tension development in neutrophil-stimulated microvascular leakage

    PubMed Central

    Breslin, Jerome W.; Sun, Hengrui; Xu, Wenjuan; Rodarte, Charles; Moy, Alan B.; Wu, Mack H.; Yuan, Sarah Y.

    2009-01-01

    Neutrophil-induced coronary microvascular barrier dysfunction is an important pathophysiological event in heart disease. Currently, the precise cellular and molecular mechanisms of neutrophil-induced microvascular leakage are not clear. The aim of this study was to test the hypothesis that rho kinase (ROCK) increases coronary venular permeability in association with elevated endothelial tension. We assessed permeability to albumin (Pa) in isolated porcine coronary venules and in coronary venular endothelial cell (CVEC) monolayers. Endothelial barrier function was also evaluated by measuring transendothelial electrical resistance (TER) of CVEC monolayers. In parallel, we measured isometric tension of CVECs grown on collagen gels. Transference of constitutively active (ca)-ROCK protein into isolated coronary venules or CVEC monolayers caused a significant increase in Pa and decreased TER in CVECs. The ROCK inhibitor Y-27632 blocked the ca-ROCK-induced changes. C5a-activated neutrophils (106/ml) also significantly elevated venular Pa, which was dose-dependently inhibited by Y-27632 and a structurally distinct ROCK inhibitor, H-1152. In CVEC monolayers, activated neutrophils increased permeability with a concomitant elevation in isometric tension, both of which were inhibited by Y-27632 or H-1152. Treatment with ca-ROCK also significantly increased CVEC monolayer permeability and isometric tension, coupled with actin polymerization and elevated phosphorylation of myosin regulatory light chain on Thr18/Ser19. The data suggest that during neutrophil activation, ROCK promotes microvascular leakage in association with actin-myosin-mediated tension development in endothelial cells. PMID:16172166

  17. Coronal leakage of sealer-only backfill: an in vitro evaluation.

    PubMed

    Whitworth, John Martin; Baco, Lina

    2005-04-01

    We tested the hypothesis that AH Plus and Roeko Seal Automix (RSA) sealers alone are no less effective in preventing coronal microleakage than gutta-percha compacted with sealer. Freshly prepared sheep incisor root canals were obturated with warm gutta-percha alone, AHPlus or RSA alone, or warm gutta-percha with AH Plus or RSA (n = 20 each group). Coronal leakage was assessed under vacuum conditions with Indian ink and tooth clearing. Sealer-only backfills with AH Plus and RSA yielded significantly more dye-free canals than backfills of gutta-percha alone or with sealer (p < 0.001). Warm gutta-percha with or without sealer kept no more canals sealer free than the positive control. Mean dye penetration was 0.92% of canal length for AH Plus and RSA backfills, 27.42% for gutta-percha only backfills, 26.47% for gutta-percha with RSA and 13.92% for gutta-percha with AH Plus. Sealer only backfills allowed significantly less leakage than those including warm gutta-percha (p < 0.001). Sealer-only backfills may be a viable alternative to traditional gutta-percha and sealer compaction methods.

  18. Air-leakage effects on stone cladding panels

    NASA Astrophysics Data System (ADS)

    Colantonio, Antonio

    1995-03-01

    This paper looks at the effects of air leakage on insulated stone clad precast panels used in present day construction of large commercial buildings. The building investigated was a newly built twenty story office building in a high density urban setting. Air leakage was suspected as a possible cause for thermal comfort complaints at isolated locations within the perimeter zones of the building. During the warrantee period the building owner asked for a quality control inspection of the air barrier assembly of the building envelope. Infrared thermography was used to locate areas of suspected air leakage within the building envelope. In order to differentiate thermal patterns produced by air leakage, conduction and convection as well as radiation from external sources, the building was inspected from the exterior; (1) after being pressurized for three hours, (2) one hour after the building was depressurized and (3) two and a half hours after total building depressurization was maintained by the building mechanical systems. Thermal images from similar locations were correlated for each time and pressure setting to verify air leakage locations within the building envelope. Areas exhibiting air leakage were identified and contractors were requested to carry out the necessary repairs. The pressure differential across the building envelope needs to be known in order to properly carry out an inspection to identify all locations of air leakage within a building envelope. As well the direction of the air movement and the density of the cladding material need to be accounted for in the proper inspection of these types of wall assemblies.

  19. Infantile amnesia: a neurogenic hypothesis.

    PubMed

    Josselyn, Sheena A; Frankland, Paul W

    2012-08-16

    In the late 19th Century, Sigmund Freud described the phenomenon in which people are unable to recall events from early childhood as infantile amnesia. Although universally observed, infantile amnesia is a paradox; adults have surprisingly few memories of early childhood despite the seemingly exuberant learning capacity of young children. How can these findings be reconciled? The mechanisms underlying this form of amnesia are the subject of much debate. Psychological/cognitive theories assert that the ability to maintain detailed, declarative-like memories in the long term correlates with the development of language, theory of mind, and/or sense of "self." However, the finding that experimental animals also show infantile amnesia suggests that this phenomenon cannot be explained fully in purely human terms. Biological explanations of infantile amnesia suggest that protracted postnatal development of key brain regions important for memory interferes with stable long-term memory storage, yet they do not clearly specify which particular aspects of brain maturation are causally related to infantile amnesia. Here, we propose a hypothesis of infantile amnesia that focuses on one specific aspect of postnatal brain development--the continued addition of new neurons to the hippocampus. Infants (humans, nonhuman primates, and rodents) exhibit high levels of hippocampal neurogenesis and an inability to form lasting memories. Interestingly, the decline of postnatal neurogenesis levels corresponds to the emergence of the ability to form stable long-term memory. We propose that high neurogenesis levels negatively regulate the ability to form enduring memories, most likely by replacing synaptic connections in preexisting hippocampal memory circuits.

  20. Instantaneous Leakage Evaluation of Metal Cask at Drop Impact

    SciTech Connect

    Hirofumi Takeda; Norihiro Kageyama; Masumi Wataru; Ryoji Sonobe; Koji Shirai; Toshiari Saegusa

    2006-07-01

    There have been a lot of tests and analyses reported for evaluation of drop tests of metal casks. However, no quantitative measurement has ever been made for any instantaneous leakage through metal gaskets during the drop tests due to loosening of the bolts in the containments and lateral sliding of the lids. In order to determine a source term for radiation exposure dose assessment, it is necessary to obtain fundamental data of instantaneous leakage. In this study, leak tests were performed by using scale models of the lid structure and a full scale cask without impact limiters simulating drop accidents in a storage facility, with aim of measuring and evaluating any instantaneous leakage at drop impact. Prior to drop tests of a full scale metal cask, a series of leakage tests using scale models were carried out to establish the measurement method and to examine a relationship between the amount of the lateral sliding of the lid and the leak rate. It was determined that the leak rate did not depend on the lateral sliding speeds. Drop tests of a full scale metal cask without impact limiters were carried out by simulating drop accidents during handling in a storage facility. The target was designed to simulate a reinforced concrete floor in the facility. The first test was a horizontal drop from a height of 1 m. The second test simulated a rotational impact around an axis of a lower trunnion of the cask from the horizontal status at a height of 1 m. In the horizontal drop test, the amount of helium gas leakage was calculated by integrating the leak rate with time. The total amount of helium gas leakage from the primary and secondary lids was 1.99 x 10{sup -6} Pa.m{sup 3}. This value is 9.61 x 10{sup -9}% of the initially installed helium gas. The amount of leakage was insignificant. In the rotational drop test, the total amount of leakage from the primary and secondary lids was 1.74 x 10{sup -5} Pa.m{sup 3}. This value is 8.45 x 10{sup -8}% of the initially installed

  1. Gas-path leakage seal for a gas turbine

    DOEpatents

    Wolfe, Christopher E.; Dinc, Osman S.; Bagepalli, Bharat S.; Correia, Victor H.; Aksit, Mahmut F.

    1996-01-01

    A gas-path leakage seal for generally sealing a gas-path leakage-gap between spaced-apart first and second members of a gas turbine (such as combustor casing segments). The seal includes a generally imperforate foil-layer assemblage which is generally impervious to gas and is located in the leakage-gap. The seal also includes a cloth-layer assemblage generally enclosingly contacting the foil-layer assemblage. In one seal, the first edge of the foil-layer assemblage is left exposed, and the foil-layer assemblage resiliently contacts the first member near the first edge to reduce leakage in the "plane" of the cloth-layer assemblage under conditions which include differential thermal growth of the two members. In another seal, such leakage is reduced by having a first weld-bead which permeates the cloth-layer assemblage, is attached to the metal-foil-layer assemblage near the first edge, and unattachedly contacts the first member.

  2. Gas-path leakage seal for a gas turbine

    DOEpatents

    Wolfe, C.E.; Dinc, O.S.; Bagepalli, B.S.; Correia, V.H.; Aksit, M.F.

    1996-04-23

    A gas-path leakage seal is described for generally sealing a gas-path leakage-gap between spaced-apart first and second members of a gas turbine (such as combustor casing segments). The seal includes a generally imperforate foil-layer assemblage which is generally impervious to gas and is located in the leakage-gap. The seal also includes a cloth-layer assemblage generally enclosingly contacting the foil-layer assemblage. In one seal, the first edge of the foil-layer assemblage is left exposed, and the foil-layer assemblage resiliently contacts the first member near the first edge to reduce leakage in the ``plane`` of the cloth-layer assemblage under conditions which include differential thermal growth of the two members. In another seal, such leakage is reduced by having a first weld-bead which permeates the cloth-layer assemblage, is attached to the metal-foil-layer assemblage near the first edge, and unattachedly contacts the first member. 4 figs.

  3. Suppression and control of leakage field in electromagnetic helical microwiggler

    SciTech Connect

    Ohigashi, N.; Tsunawaki, Y.; Imasaki, K.

    1995-12-31

    Shortening the period of electromagnetic wiggler introduces both the radical increase of the leakage field and the decrease of the field in the gap region. The leakage field is severer problem in planar electromagnetic wiggler than in helical wiggler. Hence, in order to develop a short period electromagnetic wiggler, we have adopted {open_quotes}three poles per period{close_quotes} type electromagnetic helical microwiggler. In this work, we inserted the permanent magnet (PM) blocks with specific magnetized directions in the space between magnetic poles, for suppressing the leakage field flowing out from a pole face to the neighboring pole face. These PM-blocks must have higher intrinsic coersive force than saturation field of pole material. The gap field due to each pole is adjustable by controlling the leakage fields, that is, controlling the position of each iron screw set in each retainer fixing the PM-blocks. At present time, a test wiggler with period 7.8mm, periodical number 10 and gap length 4.6mm has been manufactured. Because the ratio of PM-block aperture to gap length is important parameter to suppress the leakage field, the parameter has been surveyed experimentally for PM-blocks with several dimensions of aperture. The field strength of 3-5kG (K=0.2-0.4) would be expected in the wiggler.

  4. Homocysteine, iron and cardiovascular disease: a hypothesis.

    PubMed

    Baggott, Joseph E; Tamura, Tsunenobu

    2015-02-06

    Elevated circulating total homocysteine (tHcy) concentrations (hyperhomocysteinemia) have been regarded as an independent risk factor for cardiovascular disease (CVD). However, several large clinical trials to correct hyperhomocysteinemia using B-vitamin supplements (particularly folic acid) have largely failed to reduce the risk of CVD. There is no doubt that a large segment of patients with CVD have hyperhomocysteinemia; therefore, it is reasonable to postulate that circulating tHcy concentrations are in part a surrogate marker for another, yet-to-be-identified risk factor(s) for CVD. We found that iron catalyzes the formation of Hcy from methionine, S-adenosylhomocysteine and cystathionine. Based on these findings, we propose that an elevated amount of non-protein-bound iron (free Fe) increases circulating tHcy. Free Fe catalyzes the formation of oxygen free radicals, and oxidized low-density lipoprotein is a well-established risk factor for vascular damage. In this review, we discuss our findings on iron-catalyzed formation of Hcy from thioethers as well as recent findings by other investigators on this issue. Collectively, these support our hypothesis that circulating tHcy is in part a surrogate marker for free Fe, which is one of the independent risk factors for CVD.

  5. Codon catalog usage and the genome hypothesis.

    PubMed Central

    Grantham, R; Gautier, C; Gouy, M; Mercier, R; Pavé, A

    1980-01-01

    Frequencies for each of the 61 amino acid codons have been determined in every published mRNA sequence of 50 or more codons. The frequencies are shown for each kind of genome and for each individual gene. A surprising consistency of choices exists among genes of the same or similar genomes. Thus each genome, or kind of genome, appears to possess a "system" for choosing between codons. Frameshift genes, however, have widely different choice strategies from normal genes. Our work indicates that the main factors distinguishing between mRNA sequences relate to choices among degenerate bases. These systematic third base choices can therefore be used to establish a new kind of genetic distance, which reflects differences in coding strategy. The choice patterns we find seem compatible with the idea that the genome and not the individual gene is the unit of selection. Each gene in a genome tends to conform to its species' usage of the codon catalog; this is our genome hypothesis. PMID:6986610

  6. A quantitative methodology to assess the risks to human health from CO2 leakage into groundwater

    NASA Astrophysics Data System (ADS)

    Siirila, E.; Sitchler, A.; Maxwell, R. M.; McCray, J. E.

    2010-12-01

    Leakage of CO2 and associated gases into overlying aquifers as a result of geologic carbon capture and sequestration may have adverse impacts on aquifer drinking-water quality. Gas or aqueous-phase leakage may occur due to transport via faults and fractures, through faulty well bores, or through leaky confining materials. Contaminants of concern include aqueous salts and dissolved solids, gaseous or aqueous-phase organic contaminants, and acidic gas or aqueous-phase fluids that can liberate metals from aquifer minerals. Here we present a quantitative risk assessment framework to predict potential human health risk from CO2 leakage into drinking water aquifers. This framework incorporates the potential release of CO2 into the drinking water aquifer; mobilization of metals due to a decrease in pH; transport of these metals down gradient to municipal receptors; distributions of contaminated groundwater to multiple households; and exposure and health risk to individuals using this water for household purposes. Additionally, this framework is stochastic, incorporates detailed variations in geological and geostatistical parameters and discriminates between uncertain and variable parameters using a two-stage, or nested, Monte Carlo approach. This approach is demonstrated using example simulations with hypothetical, yet realistic, aquifer characteristics and leakage scenarios. These example simulations show a greater risk for arsenic than for lead for both cancer and non-cancer endpoints, an unexpected finding given greater toxicity of lead at lower doses than arsenic. It was also found that higher background groundwater gradients also yield higher risk. The overall risk and the associated uncertainty are sensitive to the extent of aquifer stratification and the degree of local-scale dispersion. These results all highlight the importance of hydrologic modeling in risk assessment. A linear relationship between carcinogenic and noncarcinogenic risk was found for arsenic and

  7. Identifying and Managing Gas Leakage from Subsurface Sources

    NASA Astrophysics Data System (ADS)

    Benson, S. M.

    2015-12-01

    Subsurface gas accumulations exist from both natural sources such as hydrocarbon reservoirs, as well as, man-made sources such as natural gas storage, gas pipelines, CO2 storage, or even H2 storage. Both natural and manmade sources of subsurface gases have the potential to leak to the surface. Leakage can cause safety hazards and detrimental impacts associated with the release of greenhouse gases into the atmosphere. Leak management, which involves identifying, characterizing, assessing, and remediating leakage requires a coordinated and systematic approach to effectively deal with these occurrences. Here an overall workflow for leak management is presented, along with technological options and challenges for successful implementation. Many tools and approaches for leak management are available and in use today. However, the increased attention to leakage from a larger variety of sources, particularly associated with legacy facilities and infrastructure, raises new issues and challenges that are highlighted here.

  8. Dynamic sealing principles. [design configurations for fluid leakage control

    NASA Technical Reports Server (NTRS)

    Zuk, J.

    1976-01-01

    The fundamental principles governing dynamic sealing operation are discussed. Different seals are described in terms of these principles. Despite the large variety of detailed construction, there appear to be some basic principles, or combinations of basic principles, by which all seals function. They are: (1) selection and control of seal geometry, (2) control of leakage fluid properties, and (3) control of forces acting on leakage fluids. Theoretical and practical considerations in the application of these principles are discussed. Advantages, disadvantages, limitations, and application examples of various conventional and special seals are presented. Fundamental equations governing liquid and gas flows in thin-film seals, which enable leakage calculations to be made, are also presented.

  9. Crack detection and leakage monitoring on reinforced concrete pipe

    NASA Astrophysics Data System (ADS)

    Feng, Qian; Kong, Qingzhao; Huo, Linsheng; Song, Gangbing

    2015-11-01

    Reinforced concrete underground pipelines are some of the most widely used types of structures in water transportation systems. Cracks and leakage are the leading causes of pipeline structural failures which directly results in economic losses and environmental hazards. In this paper, the authors propose a piezoceramic based active sensing approach to detect the cracks and the further leakage of concrete pipelines. Due to the piezoelectric properties, piezoceramic material can be utilized as both the actuator and the sensor in the active sensing approach. The piezoceramic patch, which is sandwiched between protective materials called ‘smart aggregates,’ can be safely embedded into concrete structures. Circumferential and axial cracks were investigated. A wavelet packet-based energy analysis was developed to distinguish the type of crack and determine the further leakage based on different stress wave energy attenuation propagated through the cracks.

  10. Air Leakage Rates in Typical Air Barrier Assemblies

    SciTech Connect

    Hun, Diana E.; Atchley, Jerald Allen; Childs, Phillip W.

    2016-11-01

    Estimates for 2010 indicate that infiltration in residential buildings was responsible for 2.85 quads of energy (DOE 2014), which is about 3% of the total energy consumed in the US. One of the mechanisms being implemented to reduce this energy penalty is the use of air barriers as part of the building envelope. These technologies decrease airflow through major leakage sites such as oriented strand board (OSB) joints, and gaps around penetrations (e.g., windows, doors, pipes, electrical outlets) as indicated by Hun et al. (2014). However, most air barrier materials do not properly address leakage spots such as wall-to-roof joints and wall-to-foundation joints because these are difficult to seal, and because air barrier manufacturers usually do not provide adequate instructions for these locations. The present study focuses on characterizing typical air leakage sites in wall assemblies with air barrier materials.

  11. Leakage radiation microscope for observation of non-transparent samples.

    PubMed

    Merlo, Juan M; Ye, Fan; Burns, Michael J; Naughton, Michael J

    2014-09-22

    We describe a leakage radiation microscope technique that can be used to extend the leakage radiation microscopy to optically non-transparent samples. In particular, two experiments are presented, first to demonstrate that acquired images with our configuration correspond to the leakage radiation phenomenon and second, to show possible applications by directly imaging a plasmonic structure that previously could only be imaged with a near-field scanning optical microscope. It is shown that the measured surface plasmon wavelength and propagation length agree with theoretically-calculated values. This configuration opens the possibility to study important effects where samples are optically non-transparent, as in plasmonic cavities and single hole plasmonic excitation, without the use of time-consuming near-field scanning optical microscopy.

  12. An Investigation of Tendon Corrosion-Inhibitor Leakage into Concrete

    SciTech Connect

    Costello, J.F.; Naus, D.J.; Oland, C.B.

    1999-07-05

    During inspections performed at US nuclear power plants several years ago, some of the prestressed concrete containment had experienced leakage of the tendon sheathing filler. A study was conducted to indicate the extent of the leakage into the concrete and its potential effects on concrete properties. Concrete core samples were obtained from the Trojan Nuclear Plant. Examination and testing of the core samples indicated that the appearance of tendon sheathing filler on the surface was due to leakage of the filler from the conduits and its subsequent migration to the concrete surface through cracks that were present. Migration of the tendon sheathing filler was confined to the cracks with no perceptible movement into the concrete. Results of compressive strength tests indicated that the concrete quality was consistent in the containment and that the strength had increased relative to the strength at 28 days age.

  13. Air Leakage of U.S. Homes: Model Prediction

    SciTech Connect

    Sherman, Max H.; McWilliams, Jennifer A.

    2007-01-01

    Air tightness is an important property of building envelopes. It is a key factor in determining infiltration and related wall-performance properties such as indoor air quality, maintainability and moisture balance. Air leakage in U.S. houses consumes roughly 1/3 of the HVAC energy but provides most of the ventilation used to control IAQ. The Lawrence Berkeley National Laboratory has been gathering residential air leakage data from many sources and now has a database of more than 100,000 raw measurements. This paper uses a model developed from that database in conjunction with US Census Bureau data for estimating air leakage as a function of location throughout the US.

  14. Ethanol-induced leakage in Saccharomyces cerevisiae: kinetics and relationship to yeast ethanol tolerance and alcohol fermentation productivity

    SciTech Connect

    Salgueiro, S.P.; Sa-Correia, I.; Novais, J.M.

    1988-04-01

    Ethanol stimulated the leakage of amino acids and 260-nm-light-absorbing compounds from cells of Saccharomyces cerevisiae. The efflux followed first-order kinetics over an initial period. In the presence of lethal concentrations of ethanol, the efflux rates at 30 and 36/sup 0/C were an exponential function of ethanol concentration. At 36/sup 0/C, as compared with the corresponding values at 30/sup 0/C, the efflux rates were higher and the minimal concentration of ethanol was lower. The exponential constants for the enhancement of the rate of leakage had similar values at 30 or 36/sup 0/C and were of the same order of magnitude as the corresponding exponential constants for ethanol-induced death. Under isothermic conditions (30/sup 0/C) and up to 22% (vol/vol) ethanol, the resistance to ethanol-induced leakage of 260-nm-light-absorbing compounds was found to be closely related with the ethanol tolerance of three strains of yeasts, Kluyveromyces marxianus, Saccharomyces cerevisiae, and Saccharomyces bayanus. The resistance to ethanol-induced leakage indicates the possible adoption of the present method for the rapid screening of ethanol-tolerant strains. The addition to a fermentation medium of the intracellular material obtained by ethanol permeabilization of yeast cells led to improvements in alcohol fermentation by S. cerevisiae and S. bayanus. The action of the intracellular material, by improving yeast ethanol tolerance, and the advantages of partially recycling the fermented medium after distillation were discussed.

  15. Albumin leakage in online hemodiafiltration, more convective transport, more losses?

    PubMed

    Vega, Almudena; Quiroga, Borja; Abad, Soraya; Aragoncillo, Inés; Arroyo, David; Panizo, Nayara; López-Gómez, Juan M

    2015-06-01

    Online hemodiafiltration (OL-HDF) has now demonstrated some benefits in reducing mortality. It seems that rising convective volumes improve the outcomes, but the risks of it, such as albumin leakage, are not well defined yet. The aim of the present study was to evaluate the albumin leakage using two different filters with 20 and 30 L of post-dilution OL-HDF. In this cross-sectional study, 20 prevalent patients receiving post-dilution OL-HDL were included. We analyzed two dialyzers: FX1000, FMC and Polyflux 210H, Gambro. During four consecutive dialysis sessions, monitors were programmed using control-volume to obtain 20 or 30 L with both dialyzers. We collected albumin samples of the effluent at 5, 15, 30, 45 and 60 min and performed area under the curve (AUC) determinations for evaluating the losses. Mean patient age was 60 ± 9 years, and 70% were men. Albumin leakage was significant higher with Polyflux 210H when compared to FX 1000 FMC. A convective volume of 30 L produced greater albumin leakage than 20 L with both filters, though only with the FX 1000 FMC was it significant (minimum albumin leakage during first hour with FX 1000 FMC 20 L: 79.2 [0.0-175.7] mg; 30 liters: 403.3 [63.5-960.7] mg; with PF 210 Gambro 20 L: 869.1 [420.0-3214.7] mg; 30 L: 1841.7 [443.8-3417.5] mg). During OL-HDF, convective transport causes albumin leakage at least during the first hour. The albumin concentration in the effluent differs according to the type of filter used and the convective volume.

  16. Atlantic multi-decadal oscillation covaries with Agulhas leakage

    SciTech Connect

    Biastoch, Arne; Durgadoo, Jonathan V.; Morrison, Adele K.; van Sebille, Erik; Weijer, Wilbert; Griffies, Stephen M.

    2015-12-10

    The interoceanic transfer of seawater between the Indian Ocean and the Atlantic, ‘Agulhas leakage’, forms a choke point for the overturning circulation in the global ocean. Here, by combining output from a series of high-resolution ocean and climate models with in situ and satellite observations, we construct a time series of Agulhas leakage for the period 1870–2014. The time series demonstrates the impact of Southern Hemisphere westerlies on decadal timescales. Agulhas leakage shows a correlation with the Atlantic Multi-decadal Oscillation on multi-decadal timescales; the former leading by 15 years. Lastly, this is relevant for climate in the North Atlantic.

  17. Leakage estimation using Kalman filtering in noninvasive mechanical ventilation.

    PubMed

    Rodrigues, G G; Freitas, U S; Bounoiare, D; Aguirre, L A; Letellier, C

    2013-05-01

    Noninvasive mechanical ventilation is today often used to assist patient with chronic respiratory failure. One of the main reasons evoked to explain asynchrony events, discomfort, unwillingness to be treated, etc., is the occurrence of nonintentional leaks in the ventilation circuit, which are difficult to account for because they are not measured. This paper describes a solution to the problem of variable leakage estimation based on a Kalman filter driven by airflow and the pressure signals, both of which are available in the ventilation circuit. The filter was validated by showing that based on the attained leakage estimates, practically all the untriggered cycles can be explained.

  18. Leakage Current and Floating Gate Capacitor Matching Test

    NASA Astrophysics Data System (ADS)

    Tian, Weidong; Trogolo, Joe R.; Todd, Bob

    Capacitor mismatch is an important device parameter for precision analog applications. In the last ten years, the floating gate measurement technique has been widely used for its characterization. In this paper we describe the impact of leakage current on the technique. The leakage can come from, for example, thin gate oxide MOSFETs or high dielectric constant capacitors in advanced technologies. SPICE simulation, bench measurement, analytical model and numerical analyses are presented to illustrate the problem and key contributing factors. Criteria for accurate capacitor systematic and random mismatch characterization are developed, and practical methods of increasing measurement accuracy are discussed.

  19. Microvascular leakage of plasma proteins after PUVA and UVA

    SciTech Connect

    Staberg, B.; Worm, A.M.; Rossing, N.; Brodthagen, H.

    1982-04-01

    The transcapillary escape rate of albumin (TERalb), is a parameter of the leakage of macromolecules from the total microvasculature. In patients with psoriasis short-term PUVA treatment induces an increase in TERalb. In this study TERalb was measured in 3 groups of normal humans treated with PUVA, UVA and 8-methoxypsoralen. Treatment with PUVA and UVA caused a statistically significant increase in TERalb, whereas treatment with 8-methoxypsoralen did not induce any measurable changes. It is concluded that the UVA irradiation causes the abnormal leakage of macromolecules, whereas psoralen is not the responsible component. Furthermore the phenomenon can be elicited in normals and is not based on a preexisting psoriasis.

  20. Importance of mineralogical data for groundwater quality affectedby CO2 leakage

    SciTech Connect

    Xu, Tianfu

    2006-02-13

    Recently, geological storage of CO{sub 2} has been extensively investigated. The impact of leakage from CO{sub 2} storage reservoirs on groundwater quality is one of the concerns. Dissolution of CO{sub 2} in groundwater results in a decrease in pH. Such acidic condition can affect the dissolution and sorption mechanisms of many minerals (Jaffe and Wang, 2004). Some heavy-metal-bearing minerals dissolve under acidic conditions. For example, galena (PbS) can dissolve and increase significantly Pb concentrations and diminish groundwater quality. If calcite is present in the rock, it can buffer the pH and decrease galena dissolution. Therefore, mineralogical composition and distribution in caprock, overlying aquifers, and along the leakage paths are important data that should be obtained from site characterization. Insight into which minerals and compounds are most important for groundwater quality can be obtained from reactive geochemical transport simulations. Here we present results of simulations using the code TOUGHREACT, whose physical and chemical process capabilities have been discussed by Xu et al. (2006). The simulator can be applied to one-, two-, or three-dimensional porous and fractured media with physical and chemical heterogeneity, and can accommodate any number of chemical species present in liquid, gas and solid phases.

  1. Visual Inspection of Water Leakage from Ground Penetrating Radar Radargram

    NASA Astrophysics Data System (ADS)

    Halimshah, N. N.; Yusup, A.; Mat Amin, Z.; Ghazalli, M. D.

    2015-10-01

    Water loss in town and suburban is currently a significant issue which reflect the performance of water supply management in Malaysia. Consequently, water supply distribution system has to be maintained in order to prevent shortage of water supply in an area. Various techniques for detecting a mains water leaks are available but mostly are time-consuming, disruptive and expensive. In this paper, the potential of Ground Penetrating Radar (GPR) as a non-destructive method to correctly and efficiently detect mains water leaks has been examined. Several experiments were designed and conducted to prove that GPR can be used as tool for water leakage detection. These include instrument validation test and soil compaction test to clarify the maximum dry density (MDD) of soil and simulation studies on water leakage at a test bed consisting of PVC pipe burying in sand to a depth of 40 cm. Data from GPR detection are processed using the Reflex 2D software. Identification of water leakage was visually inspected from the anomalies in the radargram based on GPR reflection coefficients. The results have ascertained the capability and effectiveness of the GPR in detecting water leakage which could help avoiding difficulties with other leak detection methods.

  2. Blower-door techniques for measuring interzonal leakage

    SciTech Connect

    Hult, Erin L.; Sherman, Max H.; Walker, Iain

    2013-01-01

    Abstract The standard blower door test methods, such as ASTM E779, describe how to use a single blower door to determine the total leakage of a single-zone structure such as a detached single-family home. There are no standard test methods for measuring interzonal leakage in a two-zone or multi-zone building envelope such as might be encountered in with an attached garage or in a multifamily building. Some practitioners have been using techniques that involve making multiple measurements with a single blower door as well as combined measurements using multiple blower doors. Even for just two zones there are dozens of combinations of one-door and two-door test protocols that could conceivably be used to determine the interzonal air tightness. We examined many of these two-zone configurations using both simulation and measured data to estimate the accuracy and precision of each technique for realistic measurement scenarios. We also considered the impact of taking measurements at a single pressure versus over multiple pressures. We compared the various techniques and evaluated them for specific uses. Some techniques work better in one leakage regime; some are more sensitive to wind and other noise; some are more suited to determining only a subset of the leakage values. This paper makes recommendations on which techniques to use or not use for various cases and provides data that could be used to develop future test methods.

  3. 21 CFR 870.2640 - Portable leakage current alarm.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... (CONTINUED) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Monitoring Devices § 870.2640 Portable... the electrical leakage current between any two points of an electrical system and to sound an alarm if... exempt from the premarket notification procedures in subpart E of part 807 of this chapter subject to...

  4. 21 CFR 870.2640 - Portable leakage current alarm.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... (CONTINUED) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Monitoring Devices § 870.2640 Portable... the electrical leakage current between any two points of an electrical system and to sound an alarm if... exempt from the premarket notification procedures in subpart E of part 807 of this chapter subject to...

  5. 21 CFR 870.2640 - Portable leakage current alarm.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... (CONTINUED) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Monitoring Devices § 870.2640 Portable... the electrical leakage current between any two points of an electrical system and to sound an alarm if... exempt from the premarket notification procedures in subpart E of part 807 of this chapter subject to...

  6. 21 CFR 870.2640 - Portable leakage current alarm.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... (CONTINUED) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Monitoring Devices § 870.2640 Portable... the electrical leakage current between any two points of an electrical system and to sound an alarm if... exempt from the premarket notification procedures in subpart E of part 807 of this chapter subject to...

  7. 75 FR 20546 - Total Inward Leakage Requirements for Respirators

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-04-20

    ... (CDC) is reopening the comment period for the notice of proposed rulemaking by the National Institute for Occupational Safety and Health (NIOSH) of CDC, entitled ``Total Inward Leakage Requirements for...://www.regulations.gov . Follow the instructions for submitting comments. E-mail:...

  8. Leakage Currents and Gas Generation in Advanced Wet Tantalum Capacitors

    NASA Technical Reports Server (NTRS)

    Teverovsky, Alexander

    2015-01-01

    Currently, military grade, established reliability wet tantalum capacitors are among the most reliable parts used for space applications. This has been achieved over the years by extensive testing and improvements in design and materials. However, a rapid insertion of new types of advanced, high volumetric efficiency capacitors in space systems without proper testing and analysis of degradation mechanisms might increase risks of failures. The specifics of leakage currents in wet electrolytic capacitors is that the conduction process is associated with electrolysis of electrolyte and gas generation resulting in building up of internal gas pressure in the parts. The risk associated with excessive leakage currents and increased pressure is greater for high value advanced wet tantalum capacitors, but it has not been properly evaluated yet. In this work, in Part I, leakages currents in various types of tantalum capacitors have been analyzed in a wide range of voltages, temperatures, and time under bias. Gas generation and the level of internal pressure have been calculated in Part II for different case sizes and different hermeticity leak rates to assess maximal allowable leakage currents. Effects related to electrolyte penetration to the glass seal area have been studied and the possibility of failures analyzed in Part III. Recommendations for screening and qualification to reduce risks of failures have been suggested.

  9. 49 CFR 178.345-13 - Pressure and leakage tests.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... be tested with the adjacent cargo tanks empty and at atmospheric pressure. Each closure, except... 49 Transportation 2 2010-10-01 2010-10-01 false Pressure and leakage tests. 178.345-13 Section 178... PACKAGINGS Specifications for Containers for Motor Vehicle Transportation § 178.345-13 Pressure and...

  10. Plutonium Finishing Plant assessment of confinement system bypass leakage

    SciTech Connect

    Dick, J.D.

    1996-09-30

    The purpose of this report is to document walk-through`s of the safety class confinement systems at the Plutonium Finishing Plant (PFP). In addition this document outlines the actions taken to assess the confinement system for bypass leakage as well as establishing disposition for discovered deficiencies at the PFP.

  11. Closure of cerebrospinal fluid leakage after transsphenoidal surgery: technical note.

    PubMed

    Freidberg, S R; Hybels, R L; Bohigian, R K

    1994-07-01

    It is necessary to pack the sella turcica to prevent the leakage of cerebrospinal fluid after transsphenoidal surgery if the arachnoid has been torn. The packing is usually supported by nasal cartilage. If this is not available, we recommend the Synthes minifragment plate to support the intradural pack.

  12. 42 CFR 84.123 - Exhalation valve leakage test.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 42 Public Health 1 2010-10-01 2010-10-01 false Exhalation valve leakage test. 84.123 Section 84.123 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES OCCUPATIONAL SAFETY AND HEALTH RESEARCH AND RELATED ACTIVITIES APPROVAL OF RESPIRATORY PROTECTIVE DEVICES Gas Masks §...

  13. Thresholds of information leakage for speech security outside meeting rooms.

    PubMed

    Robinson, Matthew; Hopkins, Carl; Worrall, Ken; Jackson, Tim

    2014-09-01

    This paper describes an approach to provide speech security outside meeting rooms where a covert listener might attempt to extract confidential information. Decision-based experiments are used to establish a relationship between an objective measurement of the Speech Transmission Index (STI) and a subjective assessment relating to the threshold of information leakage. This threshold is defined for a specific percentage of English words that are identifiable with a maximum safe vocal effort (e.g., "normal" speech) used by the meeting participants. The results demonstrate that it is possible to quantify an offset that links STI with a specific threshold of information leakage which describes the percentage of words identified. The offsets for male talkers are shown to be approximately 10 dB larger than for female talkers. Hence for speech security it is possible to determine offsets for the threshold of information leakage using male talkers as the "worst case scenario." To define a suitable threshold of information leakage, the results show that a robust definition can be based upon 1%, 2%, or 5% of words identified. For these percentages, results are presented for offset values corresponding to different STI values in a range from 0.1 to 0.3.

  14. Detectivity of gas leakage based on electromagnetic radiation transfer

    NASA Astrophysics Data System (ADS)

    Long, Yunting; Wang, Lingxue; Li, Jiakun; Zhang, Changxing; Zhang, Bei

    2011-05-01

    Standoff detection of gas leakage is a fundamental need in petrochemical and power industries. The passive gas imaging system using thermal imager has been proven to be efficient to visualize leaking gas which is not visible to the naked eye. The detection probability of gas leakage is the basis for designing a gas imaging system. Supposing the performance parameters of the thermal imager are known, the detectivity based on electromagnetic radiation transfer model to image gas leakage is analyzed. This model takes into consideration a physical analysis of the gas plume spread in the atmosphere-the interaction processes between the gas and its surrounding environment, the temperature of the gas and the background, the background surface emissivity, and also gas concentration, etc. Under a certain environmental conditions, through calculating the radiation reaching to the detector from the camera's optical field of view, we obtain an entity "Gas Equivalent Blackbody Temperature Difference (GEBTD)" which is the radiation difference between the on-plume and off-plume regions. Comparing the GEBTD with the Noise Equivalent Temperature Difference (NETD) of the thermal imager, we can know whether the system can image the gas leakage. At last, an example of detecting CO2 gas by JADE MWIR thermal imager with a narrow band-pass filter is presented.

  15. Osmotic Stressing, Membrane Leakage, and Fluorescence: An Introductory Biochemistry Demonstration

    ERIC Educational Resources Information Center

    Seu, Kalani J.

    2015-01-01

    A fluorescence demonstration is described that incorporates several fundamental aspects of an introductory biochemistry course. A variation of a known leakage assay is utilized to prepare vesicles containing a quenched fluorophore. The vesicles are exposed to several osmotic environments ranging from isotonic to hypotonic. The degree of vesicle…

  16. 40 CFR 265.222 - Action leakage rate.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... system (LDS) can remove without the fluid head on the bottom liner exceeding 1 foot. The action leakage..., hydraulic conductivity, thickness of drainage material), construction, operation, and location of the LDS... the system over time resulting from siltation and clogging, rib layover and creep of...

  17. Leakage diffusion of underwater crude oil in wind fields.

    PubMed

    Chen, Liqiong; Liu, Qi; Li, Yunyun; Lu, Rui; Wu, Shijuan; Li, Xin; Hou, Tao

    2016-01-01

    Leakage of underwater crude oil pipes causes severe pollution to soil and water, and results in great economic loss. To predict the diffusion area of spilled oil before it reaches the water's surface and to reduce the time required for emergency response, numerical simulations were conducted on underwater spilled oil diffusion of bare crude oil pipes using FLUENT software. The influences of water-surface wind speed, leakage hole diameter, water velocity, and initial leakage velocity on oil diffusion were analyzed. The results revealed the following: (1) with wind blowing on the surface of the water, the vertical displacement of spilled oil jet-flow was affected by the combined action of water flow and wind, making it difficult for a high-speed jet-flow to form. A horizontal oil flow mostly moved in the direction of the bottom water, and frontier oil droplets dispersed quickly; (2) during the diffusion of spilled oil in water, the maximum horizontal displacement mostly increased linearly, while the maximum vertical displacement initially increased quickly and then slowed; (3) the greater the initial velocity and leakage hole diameter, the higher the oil jet-flow and the wider the diffusion area; the higher the water flow rate and water-surface wind speed, the smaller the vertical displacement of spilled oil. The existence of water-surface wind had no obvious influence on the horizontal displacement of underwater spilled oil.

  18. Minimum permissible leakage resistance established for instrumentation systems

    NASA Technical Reports Server (NTRS)

    Perrin, J. L.

    1966-01-01

    Mathematical formulas are used to determine if, and to what extent, an instrumentation system that has been exposed to the elements should be dried out to restore minimum permissible leakage resistance to ground. Formulas are also derived and used for an intermediate number of systems that are exposed to moisture penetration.

  19. 42 CFR 84.123 - Exhalation valve leakage test.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 42 Public Health 1 2011-10-01 2011-10-01 false Exhalation valve leakage test. 84.123 Section 84.123 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES OCCUPATIONAL SAFETY AND HEALTH RESEARCH AND RELATED ACTIVITIES APPROVAL OF RESPIRATORY PROTECTIVE DEVICES Gas Masks §...

  20. 42 CFR 84.123 - Exhalation valve leakage test.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 42 Public Health 1 2012-10-01 2012-10-01 false Exhalation valve leakage test. 84.123 Section 84.123 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES OCCUPATIONAL SAFETY AND HEALTH RESEARCH AND RELATED ACTIVITIES APPROVAL OF RESPIRATORY PROTECTIVE DEVICES Gas Masks §...

  1. 42 CFR 84.123 - Exhalation valve leakage test.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 42 Public Health 1 2014-10-01 2014-10-01 false Exhalation valve leakage test. 84.123 Section 84.123 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES OCCUPATIONAL SAFETY AND HEALTH RESEARCH AND RELATED ACTIVITIES APPROVAL OF RESPIRATORY PROTECTIVE DEVICES Gas Masks §...

  2. 42 CFR 84.123 - Exhalation valve leakage test.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 42 Public Health 1 2013-10-01 2013-10-01 false Exhalation valve leakage test. 84.123 Section 84.123 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES OCCUPATIONAL SAFETY AND HEALTH RESEARCH AND RELATED ACTIVITIES APPROVAL OF RESPIRATORY PROTECTIVE DEVICES Gas Masks §...

  3. 40 CFR 89.316 - Analyzer leakage and response time.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ....316 Section 89.316 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS...) The maximum allowable leakage rate on the vacuum side is 0.5 percent of the in-use flow rate for the portion of the system being checked. The analyzer flows and bypass flows may be used to estimate the...

  4. 40 CFR 89.316 - Analyzer leakage and response time.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ....316 Section 89.316 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS...) The maximum allowable leakage rate on the vacuum side is 0.5 percent of the in-use flow rate for the portion of the system being checked. The analyzer flows and bypass flows may be used to estimate the...

  5. 40 CFR 89.316 - Analyzer leakage and response time.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ....316 Section 89.316 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS...) The maximum allowable leakage rate on the vacuum side is 0.5 percent of the in-use flow rate for the portion of the system being checked. The analyzer flows and bypass flows may be used to estimate the...

  6. 40 CFR 89.316 - Analyzer leakage and response time.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ....316 Section 89.316 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS...) The maximum allowable leakage rate on the vacuum side is 0.5 percent of the in-use flow rate for the portion of the system being checked. The analyzer flows and bypass flows may be used to estimate the...

  7. Exploitation of Unintentional Information Leakage from Integrated Circuits

    ERIC Educational Resources Information Center

    Cobb, William E.

    2011-01-01

    The information leakage of electronic devices, especially those used in cryptographic or other vital applications, represents a serious practical threat to secure systems. While physical implementation attacks have evolved rapidly over the last decade, relatively little work has been done to allow system designers to effectively counter the…

  8. THE CARBON DIOXIDE LEAKAGE FROM CHAMBERS MEASURED USING SULFUR HEXAFLUORIDE

    EPA Science Inventory

    In plant chamber studies, if Co2 leaking from a chamber is not quantified, it can lead to an overestimate of assimilation rates and an underestimate of respiration rates: consequently, it is critical that Co2 leakage be determined. Sulfur Hexafluoride (SF6) was introduced into t...

  9. Can paternal leakage maintain sexually antagonistic polymorphism in the cytoplasm?

    PubMed Central

    Kuijper, B; Lane, N; Pomiankowski, A

    2015-01-01

    A growing number of studies in multicellular organisms highlight low or moderate frequencies of paternal transmission of cytoplasmic organelles, including both mitochondria and chloroplasts. It is well established that strict maternal inheritance is selectively blind to cytoplasmic elements that are deleterious to males – ’mother's curse’. But it is not known how sensitive this conclusion is to slight levels of paternal cytoplasmic leakage. We assess the scope for polymorphism when individuals bear multiple cytoplasmic alleles in the presence of paternal leakage, bottlenecks and recurrent mutation. When fitness interactions among cytoplasmic elements within an individual are additive, we find that sexually antagonistic polymorphism is restricted to cases of strong selection on males. However, when fitness interactions among cytoplasmic elements are nonlinear, much more extensive polymorphism can be supported in the cytoplasm. In particular, mitochondrial mutants that have strong beneficial fitness effects in males and weak deleterious fitness effects in females when rare (i.e. ’reverse dominance’) are strongly favoured under paternal leakage. We discuss how such epistasis could arise through preferential segregation of mitochondria in sex-specific somatic tissues. Our analysis shows how paternal leakage can dampen the evolution of deleterious male effects associated with predominant maternal inheritance of cytoplasm, potentially explaining why ’mother's curse’ is less pervasive than predicted by earlier work. PMID:25653025

  10. 40 CFR 265.255 - Action leakage rates.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... maximum design flow rate that the leak detection system (LDS) can remove without the fluid head on the... the action leakage rate has been exceeded, the owner or operator must convert the weekly flow rate from the monitoring data obtained under § 265.260, to an average daily flow rate (gallons per acre...

  11. 40 CFR 264.252 - Action leakage rate.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... flow rate that the leak detection system (LDS) can remove without the fluid head on the bottom liner... action leakage rate has been exceeded, the owner or operator must convert the weekly flow rate from the monitoring data obtained under § 264.254(c) to an average daily flow rate (gallons per acre per day) for...

  12. 40 CFR 264.222 - Action leakage rate.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... design flow rate that the leak detection system (LDS) can remove without the fluid head on the bottom... action leakage rate has been exceeded, the owner or operator must convert the weekly or monthly flow rate from the monitoring data obtained under § 264.226(d) to an average daily flow rate (gallons per...

  13. 40 CFR 264.302 - Action leakage rate.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... landfill units subject to § 264.301(c) or (d). The action leakage rate is the maximum design flow rate that...) STANDARDS FOR OWNERS AND OPERATORS OF HAZARDOUS WASTE TREATMENT, STORAGE, AND DISPOSAL FACILITIES Landfills... design (e.g., slope, hydraulic conductivity, thickness of drainage material), construction,...

  14. 40 CFR 265.302 - Action leakage rate.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... FACILITIES Landfills § 265.302 Action leakage rate. (a) The owner or operator of landfill units subject to... maximum design flow rate that the leak detection system (LDS) can remove without the fluid head on the... for uncertainties in the design (e.g., slope, hydraulic conductivity, thickness of drainage...

  15. 40 CFR 264.302 - Action leakage rate.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... landfill units subject to § 264.301(c) or (d). The action leakage rate is the maximum design flow rate that...) STANDARDS FOR OWNERS AND OPERATORS OF HAZARDOUS WASTE TREATMENT, STORAGE, AND DISPOSAL FACILITIES Landfills... design (e.g., slope, hydraulic conductivity, thickness of drainage material), construction,...

  16. 40 CFR 264.302 - Action leakage rate.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... landfill units subject to § 264.301(c) or (d). The action leakage rate is the maximum design flow rate that...) STANDARDS FOR OWNERS AND OPERATORS OF HAZARDOUS WASTE TREATMENT, STORAGE, AND DISPOSAL FACILITIES Landfills... design (e.g., slope, hydraulic conductivity, thickness of drainage material), construction,...

  17. 40 CFR 265.302 - Action leakage rate.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... FACILITIES Landfills § 265.302 Action leakage rate. (a) The owner or operator of landfill units subject to... maximum design flow rate that the leak detection system (LDS) can remove without the fluid head on the... for uncertainties in the design (e.g., slope, hydraulic conductivity, thickness of drainage...

  18. 40 CFR 265.302 - Action leakage rate.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... FACILITIES Landfills § 265.302 Action leakage rate. (a) The owner or operator of landfill units subject to... maximum design flow rate that the leak detection system (LDS) can remove without the fluid head on the... for uncertainties in the design (e.g., slope, hydraulic conductivity, thickness of drainage...

  19. Ecosystem Succession and Nutrient Retention: A Hypothesis

    ERIC Educational Resources Information Center

    Vitousek, Peter M.; Reiners, William A.

    1975-01-01

    A hypothesis is presented for the regulation of elemental losses from terrestrial ecosystems. Losses of elements are controlled by the net increment of biomass growth and the elemental composition of this net increment. According to this hypothesis, loss rates are highest in early succession and in steady state ecosystems. (Author/EB)

  20. A Model of the Relative Income Hypothesis

    ERIC Educational Resources Information Center

    Sanders, Shane

    2010-01-01

    James Duesenberry's (1949) relative income hypothesis holds substantial empirical credibility, as well as a rich set of implications. Although present in the pages of leading economics journals, the hypothesis has become all but foreign to the blackboards of economics classrooms. To help reintegrate the concept into the undergraduate economics…

  1. Current Status of the Molecular Clock Hypothesis

    ERIC Educational Resources Information Center

    Hermann, Gilbert

    2003-01-01

    Molecular genetics is a rapidly changing field with new developments almost from day to day. One interesting hypothesis that has come from everyone's ability to sequence proteins and/or genes is that of the molecular clock. This hypothesis postulates that homologous sequences of DNA and thus macro molecules evolve at a constant and invariable rate…

  2. Statistics and Hypothesis Testing in Biology.

    ERIC Educational Resources Information Center

    Maret, Timothy J.; Ziemba, Robert E.

    1997-01-01

    Suggests that early in their education students be taught to use basic statistical tests as rigorous methods of comparing experimental results with scientific hypotheses. Stresses that students learn how to use statistical tests in hypothesis-testing by applying them in actual hypothesis-testing situations. To illustrate, uses questions such as…

  3. The Interaction Hypothesis: A Critical Evaluation.

    ERIC Educational Resources Information Center

    Ellis, Rod

    The oral interaction hypothesis, proposed by Long and investigated by Pica, in second language (L2) acquisition is critiqued. The interaction hypothesis advances two major claims about the role of interaction in L2 acquisition: (1) comprehensible input is necessary for L2 acquisition; and (2) modifications to the interactional structure of…

  4. Statistical reasoning in clinical trials: hypothesis testing.

    PubMed

    Kelen, G D; Brown, C G; Ashton, J

    1988-01-01

    Hypothesis testing is based on certain statistical and mathematical principles that allow investigators to evaluate data by making decisions based on the probability or implausibility of observing the results obtained. However, classic hypothesis testing has its limitations, and probabilities mathematically calculated are inextricably linked to sample size. Furthermore, the meaning of the p value frequently is misconstrued as indicating that the findings are also of clinical significance. Finally, hypothesis testing allows for four possible outcomes, two of which are errors that can lead to erroneous adoption of certain hypotheses: 1. The null hypothesis is rejected when, in fact, it is false. 2. The null hypothesis is rejected when, in fact, it is true (type I or alpha error). 3. The null hypothesis is conceded when, in fact, it is true. 4. The null hypothesis is conceded when, in fact, it is false (type II or beta error). The implications of these errors, their relation to sample size, the interpretation of negative trials, and strategies related to the planning of clinical trials will be explored in a future article in this journal.

  5. Knowledge dimensions in hypothesis test problems

    NASA Astrophysics Data System (ADS)

    Krishnan, Saras; Idris, Noraini

    2012-05-01

    The reformation in statistics education over the past two decades has predominantly shifted the focus of statistical teaching and learning from procedural understanding to conceptual understanding. The emphasis of procedural understanding is on the formulas and calculation procedures. Meanwhile, conceptual understanding emphasizes students knowing why they are using a particular formula or executing a specific procedure. In addition, the Revised Bloom's Taxonomy offers a twodimensional framework to describe learning objectives comprising of the six revised cognition levels of original Bloom's taxonomy and four knowledge dimensions. Depending on the level of complexities, the four knowledge dimensions essentially distinguish basic understanding from the more connected understanding. This study identifiesthe factual, procedural and conceptual knowledgedimensions in hypothesis test problems. Hypothesis test being an important tool in making inferences about a population from sample informationis taught in many introductory statistics courses. However, researchers find that students in these courses still have difficulty in understanding the underlying concepts of hypothesis test. Past studies also show that even though students can perform the hypothesis testing procedure, they may not understand the rationale of executing these steps or know how to apply them in novel contexts. Besides knowing the procedural steps in conducting a hypothesis test, students must have fundamental statistical knowledge and deep understanding of the underlying inferential concepts such as sampling distribution and central limit theorem. By identifying the knowledge dimensions of hypothesis test problems in this study, suitable instructional and assessment strategies can be developed in future to enhance students' learning of hypothesis test as a valuable inferential tool.

  6. Radiation leakage dose from Elekta electron collimation system.

    PubMed

    Pitcher, Garrett M; Hogstrom, Kenneth R; Carver, Robert L

    2016-09-08

    This study provided baseline data required for a greater project, whose objective was to design a new Elekta electron collimation system having significantly lighter electron applicators with equally low out-of field leakage dose. Specifically, off-axis dose profiles for the electron collimation system of our uniquely configured Elekta Infinity accelerator with the MLCi2 treatment head were measured and calculated for two primary purposes: 1) to evaluate and document the out-of-field leakage dose in the patient plane and 2) to validate the dose distributions calculated using a BEAMnrc Monte Carlo (MC) model for out-of-field dose profiles. Off-axis dose profiles were measured in a water phantom at 100 cm SSD for 1 and 2 cm depths along the in-plane, cross-plane, and both diagonal axes using a cylindrical ionization chamber with the 10 × 10 and 20 × 20 cm2 applicators and 7, 13, and 20 MeV beams. Dose distributions were calculated using a previously developed BEAMnrc MC model of the Elekta Infinity accelerator for the same beam energies and applicator sizes and compared with measurements. Measured results showed that the in-field beam flatness met our acceptance criteria (± 3% on major and ±4% on diagonal axes) and that out-of-field mean and maximum percent leakage doses in the patient plane met acceptance criteria as specified by the International Electrotechnical Commission (IEC). Cross-plane out-of-field dose profiles showed greater leakage dose than in-plane profiles, attributed to the curved edges of the upper X-ray jaws and multileaf collimator. Mean leakage doses increased with beam energy, being 0.93% and 0.85% of maximum central axis dose for the 10 × 10 and 20 × 20 cm2 applicators, respectively, at 20 MeV. MC calculations predicted the measured dose to within 0.1% in most profiles outside the radiation field; however, excluding model-ing of nontrimmer applicator components led to calculations exceeding measured data by as much as 0.2% for some regions

  7. Evaluation of particulate filtering respirators using inward leakage (IL) or total inward leakage (TIL) testing--Korean experience.

    PubMed

    Han, Don-Hee; Lee, Jinheon

    2005-10-01

    Korean certification regulation for particulate filtering respirators requires inward leakage (IL) or total inward leakage (TIL) testing according to European Standard EN 13274-1, and the standard levels of compliance are similar to those of the European Standard. This study was conducted to evaluate particulate filtering respirators being commercially used in the Korean market using an IL or TIL test and the validity of standard level in Korea. Three half masks and 10 filtering facepieces (two top class, four 1st class and four 2nd class)-a total of 13 brand name respirators-were selected for the test with panels of 10 subjects. Each subject was classified with nine facial dimension grid squares in accordance with face length and lip length. IL or TIL testing was conducted at the laboratory of the 3M Innovation Center in which the experimental instruments and systems were established in compliance with European standards. The testing procedure followed EN 13274-1 (2001). As expected, leakages of half masks were less than those of filtering facepieces and the latter were significantly different among brands. TILs of the 1st class filtering facepieces were found to be much more than those of the 2nd class and the result may cause a wearer to get confused when selecting a mask. The main route leakage for filtering facepieces may not be the filter medium but the face seal. Therefore, it is necessary to develop well-fitting filtering facepieces for Koreans. Because leakages were significantly different for different facial dimensions, a defined test panel for IL or TIL testing according to country or race should be developed. A more precise method to demonstrate fit, for example, fit testing such as in the US regulations, will be needed before IL or TIL testing or when selecting a respirator. Another finding implies that geometric mean of five exercises for IL or TIL may be better than arithmetic mean to establish a standard individual subject mean.

  8. Hypothesis-free? No such thing

    SciTech Connect

    Wiley, H. S.

    2008-06-01

    Finding meaningful relationships in complex datasets requires starting with the appropriate data. A hypothesis usually takes the form of a mechanistic relationship between a specific cause and a consequent effect, and this will almost always depend on experimental context. There are some circumstances when data must be gathered in the absence of context or hypothesis to characterize a system, but it is unrealistic to expect such preliminary studies to lead to significant biological insights. For this, you need a hypothesis. Systems biology might be the future of biology, but we still need hypotheses to take us where we want to go.

  9. Leakage of Experimental Information to Potential Future Subjects by Debriefed Subjects

    ERIC Educational Resources Information Center

    Diener, Edward; And Others

    1972-01-01

    Leakage of experimental information from debreifed subjects into a university subject pool was studied. It was concluded that in settings similar to those of the experiment, leakage of information is not a serious problem. (Authors)

  10. Hypothesis Testing with Computer-Assisted Instruction.

    ERIC Educational Resources Information Center

    Schwartz, Helen J.

    1983-01-01

    Describes the components of SEEN, a computer program which provides an environment that prompts the user to create, support, and test an hypothesis, and its applications in an introductory world literature and an art history course. (MBR)

  11. Killing Me Softly: The Fetal Origins Hypothesis*

    PubMed Central

    Almond, Douglas

    2013-01-01

    In the epidemiological literature, the fetal origins hypothesis associated with David J. Barker posits that chronic, degenerative conditions of adult health, including heart disease and type 2 diabetes, may be triggered by circumstance decades earlier, in utero nutrition in particular. Economists have expanded on this hypothesis, investigating a broader range of fetal shocks and circumstances and have found a wealth of later-life impacts on outcomes including test scores, educational attainment, and income, along with health. In the process, they have provided some of the most credible observational evidence in support of the hypothesis. The magnitude of the impacts is generally large. Thus, the fetal origins hypothesis has not only survived contact with economics, but has flourished. PMID:25152565

  12. 77 FR 14445 - Leakage Tests on Packages for Shipment of Radioactive Material

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-03-09

    ... COMMISSION Leakage Tests on Packages for Shipment of Radioactive Material AGENCY: Nuclear Regulatory... Commission) is issuing a revision to Regulatory Guide 7.4, ``Leakage Tests on Packages for Radioactive... Standard N14.5-1997, ``Radioactive Materials--Leakage Tests on Packages for Shipment'' approved...

  13. 47 CFR 76.1706 - Signal leakage logs and repair records.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 47 Telecommunication 4 2012-10-01 2012-10-01 false Signal leakage logs and repair records. 76.1706... leakage logs and repair records. Cable operators shall maintain a log showing the date and location of... the probable cause of the leakage. The log shall be kept on file for a period of two years and...

  14. 47 CFR 76.1706 - Signal leakage logs and repair records.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 47 Telecommunication 4 2014-10-01 2014-10-01 false Signal leakage logs and repair records. 76.1706... leakage logs and repair records. Cable operators shall maintain a log showing the date and location of... the probable cause of the leakage. The log shall be kept on file for a period of two years and...

  15. 47 CFR 76.1706 - Signal leakage logs and repair records.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 47 Telecommunication 4 2011-10-01 2011-10-01 false Signal leakage logs and repair records. 76.1706... leakage logs and repair records. Cable operators shall maintain a log showing the date and location of... the probable cause of the leakage. The log shall be kept on file for a period of two years and...

  16. 47 CFR 76.1706 - Signal leakage logs and repair records.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 47 Telecommunication 4 2013-10-01 2013-10-01 false Signal leakage logs and repair records. 76.1706... leakage logs and repair records. Cable operators shall maintain a log showing the date and location of... the probable cause of the leakage. The log shall be kept on file for a period of two years and...

  17. 47 CFR 76.1706 - Signal leakage logs and repair records.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 47 Telecommunication 4 2010-10-01 2010-10-01 false Signal leakage logs and repair records. 76.1706... leakage logs and repair records. Cable operators shall maintain a log showing the date and location of... the probable cause of the leakage. The log shall be kept on file for a period of two years and...

  18. Self-healable and reversible liposome leakage by citrate-capped gold nanoparticles: probing the initial adsorption/desorption induced lipid phase transition

    NASA Astrophysics Data System (ADS)

    Wang, Feng; Liu, Juewen

    2015-09-01

    We herein report that the adsorption/desorption of citrate-capped gold nanoparticles (AuNPs) transiently causes leakage in fluid phase DOPC liposomes, while the liposomes do not leak with AuNPs capped with mercaptopropionic acid (MPA). Leakage also fails to occur for gel phase DPPC liposomes. Citrate-capped (but not MPA-capped) AuNPs raise the phase transition temperature of DPPC. We conclude that citrate-capped AuNPs interact with the PC liposomes very strongly, inducing a local fluid-to-gel lipid phase transition for DOPC. Leakage takes place during this transition, and the membrane integrity is resumed after the transition. Citrate-capped AuNPs allow stronger van der Waals forces than MPA-capped AuNPs with PC liposomes, since the latter are separated from the liposome surface by the ~0.3 nm MPA layer.We herein report that the adsorption/desorption of citrate-capped gold nanoparticles (AuNPs) transiently causes leakage in fluid phase DOPC liposomes, while the liposomes do not leak with AuNPs capped with mercaptopropionic acid (MPA). Leakage also fails to occur for gel phase DPPC liposomes. Citrate-capped (but not MPA-capped) AuNPs raise the phase transition temperature of DPPC. We conclude that citrate-capped AuNPs interact with the PC liposomes very strongly, inducing a local fluid-to-gel lipid phase transition for DOPC. Leakage takes place during this transition, and the membrane integrity is resumed after the transition. Citrate-capped AuNPs allow stronger van der Waals forces than MPA-capped AuNPs with PC liposomes, since the latter are separated from the liposome surface by the ~0.3 nm MPA layer. Electronic supplementary information (ESI) available: Methods, TEM, UV-vis and DLS data. See DOI: 10.1039/c5nr04805b

  19. Gas-path leakage seal for a turbine

    DOEpatents

    Bagepalli, Bharat Sampathkumaran; Aksit, Mahmut Faruk; Farrell, Thomas Raymond

    1999-01-01

    A gas-path leakage seal for generally sealing a gas-path leakage-gap between spaced-apart first and second members of a turbine (such as combustor casing segments of a gas turbine). The seal includes a flexible and generally imperforate metal sheet assemblage having opposing first and second surfaces and two opposing raised edges extending a generally identical distance above and below the surfaces. A first cloth layer assemblage has a thickness generally equal to the previously-defined identical distance and is superimposed on the first surface between the raised edges. A second cloth layer assemblage is generally identical to the first cloth layer assemblage and is superimposed on the second surface between the raised edges.

  20. Gas-path leakage seal for a turbine

    DOEpatents

    Bagepalli, B.S.; Aksit, M.F.; Farrell, T.R.

    1999-08-10

    A gas-path leakage seal for generally sealing a gas-path leakage-gap between spaced-apart first and second members of a turbine (such as combustor casing segments of a gas turbine). The seal includes a flexible and generally imperforate metal sheet assemblage having opposing first and second surfaces and two opposing raised edges extending a generally identical distance above and below the surfaces. A first cloth layer assemblage has a thickness generally equal to the previously-defined identical distance and is superimposed on the first surface between the raised edges. A second cloth layer assemblage is generally identical to the first cloth layer assemblage and is superimposed on the second surface between the raised edges. 5 figs.

  1. Turbocharger with sliding piston, and having vanes and leakage dams

    DOEpatents

    Roberts, Quentin; Alnega, Ahmed

    2011-12-06

    A turbocharger having a sliding piston for regulating exhaust gas flow into the turbine wheel includes a set of first vanes mounted on a fixed first wall of the turbine nozzle and projecting axially toward an opposite second wall of the nozzle, and/or a set of second vanes mounted on the end of the piston and projecting in an opposite axial direction toward the first wall of the nozzle. For the/each set of vanes, there are leakage dams formed on the wall that is adjacent the vane tips when the piston is closed. The leakage dams are closely adjacent the vane tips and discourage exhaust gas from leaking in a generally radial direction past the vane tips as the piston just begins to open from its fully closed position.

  2. Bacteriocin typing by leakage of ultraviolet light-absorbing material.

    PubMed Central

    Farkas-Himsley, H; Pagel, A

    1977-01-01

    A rapid and reproducible method of bacteriocin typing is described based on leakage of ultraviolet light-absorbing material (UVAM), detectable in supernatants of bacteriocin-sensitive cultures, by means of a spectrophotometer. The prerequisites for reproducible results, with nonsignificant fluctuations in standard error of the mean, are: a set of standardized bacteriocins, produced under defined conditions and of determined strength. These must interact with the unknown bacterial culture in suspension and at a given ratio in order to achieve an optimal multiplicity of interaction. Pyocin and colicin typing by the "scrape and streak" technique of Gillies (J. Hyg. 62:1-10, 1963) was compared with the UVAM leakage method in 275 tests; the two tests were found to be in good agreement for the strains tested. PMID:406200

  3. Leakage current measurements of a pixelated polycrystalline CVD diamond detector

    NASA Astrophysics Data System (ADS)

    Zain, R. M.; Maneuski, D.; O'Shea, V.; Bates, R.; Blue, A.; Cunnigham, L.; Stehl, C.; Berderman, E.; Rahim, R. A.

    2013-01-01

    Diamond has several desirable features when used as a material for radiation detection. With the invention of synthetic growth techniques, it has become feasible to look at developing diamond radiation detectors with reasonable surface areas. Polycrystalline diamond has been grown using a chemical vapour deposition (CVD) technique by the University of Augsburg and detector structures fabricated at the James Watt Nanofabrication Centre (JWNC) in the University of Glasgow in order to produce pixelated detector arrays. The anode and cathode contacts are realised by depositing gold to produce ohmic contacts. Measurements of I-V characteristics were performed to study the material uniformity. The bias voltage is stepped from -1000V to 1000V to investigate the variation of leakage current from pixel to pixel. Bulk leakage current is measured to be less than 1nA.

  4. Leakage currents in 4H-SiC JBS diodes

    SciTech Connect

    Ivanov, P. A. Grekhov, I. V.; Potapov, A. S.; Kon'kov, O. I.; Il'inskaya, N. D.; Samsonova, T. P.; Korol'kov, O.; Sleptsuk, N.

    2012-03-15

    Leakage currents in high-voltage 4H-SiC diodes, which have an integrated (p-n) Schottky structure (Junction Barrier Schottky, JBS), have been studied using commercial diodes and specially fabricated (based on a commercial epitaxial material) test Schottky diodes with and without the JBS structure. It is shown that (i) the main role in reverse charge transport is played by SiC crystal structure defects, most probably, by threading dislocations (density {approx}10{sup 4} cm{sup -2}), and (ii) the JBS structure, formed by the implantation of boron, partially suppresses the leakage currents (by up to a factor of 10 at optimal separation, 8 {mu}m between local p-type regions).

  5. Peptic ulcer perforation: sonographic imaging of active fluid leakage.

    PubMed

    Minardos, Ioannis; Ioannis, Minardos; Ziogana, Dimitra; Dimitra, Ziogana; Hristopoulos, Hristos; Hristos, Hristopoulos; Dermitzakis, Ioannis; Ioannis, Dermitzakis

    2006-01-01

    Sonography is not the method of choice for the evaluation of suspected peptic ulcer perforation (PUP). However, indirect sonographic signs and direct visualization of PUP have been reported by several authors in recent years. We report a case of an elderly woman who presented with severe abdominal pain and positive rebound sign, in whom abdominal sonography demonstrated indirect signs of PUP, the site of perforation, and active air fluid leakage through the perforated anterior prepyloric antral wall.

  6. Alternative magnetic flux leakage modalities for pipeline inspection

    SciTech Connect

    Katragadda, G.; Lord, W.; Sun, Y.S.; Udpa, S.; Udpa, L.

    1996-05-01

    Increasing quality consciousness is placing higher demands on the accuracy and reliability of inspection systems used in defect detection and characterization. Nondestructive testing techniques often rely on using multi-transducer approaches to obtain greater defect sensitivity. This paper investigates the possibility of taking advantage of alternative modalities associated with the standard magnetic flux leakage tool to obtain additional defect information, while still using a single excitation source.

  7. Rotordynamic and Leakage Characteristics of a 4-Stage Brush Seal

    DTIC Science & Technology

    1992-12-01

    AD-A266 012 WL-TR-92-2125 .AP ROTORDYNAMIC AND LEAKAGE CHARACTERISTICS OF A 4-STAGE BRUSH SEAL K. J. CONNER D. W. CHILDS TURBOMACHINERY LABORATORIES...pre-rotation, and seal spacing. Direct damping is shown to increase with running speed; otherwise, the rotordynamic coefficients are relatively...test results for the 4-stage brush seal with an 8-cavity labyrinth showed superior rotordynamics performance for the brush seal; viz., larger values for

  8. Binding and leakage of barium in alginate microbeads.

    PubMed

    Mørch, Yrr A; Qi, Meirigeng; Gundersen, Per Ole M; Formo, Kjetil; Lacik, Igor; Skjåk-Braek, Gudmund; Oberholzer, Jose; Strand, Berit L

    2012-11-01

    Microbeads of alginate crosslinked with Ca(2+) and/or Ba(2+) are popular matrices in cell-based therapy. The aim of this study was to quantify the binding of barium in alginate microbeads and its leakage under in vitro and accumulation under in vivo conditions. Low concentrations of barium (1 mM) in combination with calcium (50 mM) and high concentrations of barium (20 mM) in gelling solutions were used for preparation of microbeads made of high-G and high-M alginates. High-G microbeads accumulated barium from gelling solution and contained higher concentrations of divalent ions for both low- and high-Ba exposure compared with high-G microbeads exposed to calcium solely and to high-M microbeads for all gelling conditions. Although most of the unbound divalent ions were removed during the wash and culture steps, leakage of barium was still detected during storage. Barium accumulation in blood and femur bone of mice implanted with high-G beads was found to be dose-dependent. Estimated barium leakage relevant to transplantation to diabetic patients with islets in alginate microbeads showed that the leakage was 2.5 times lower than the tolerable intake value given by WHO for high-G microbeads made using low barium concentration. The similar estimate gave 1.5 times higher than is the tolerable intake value for the high-G microbeads made using high barium concentration. To reduce the risk of barium accumulation that may be of safety concern, the microbeads made of high-G alginate gelled with a combination of calcium and low concentration of barium ions is recommended for islet transplantation.

  9. Single-Photon Secure Quantum Dialogue Protocol Without Information Leakage

    NASA Astrophysics Data System (ADS)

    Zhou, Nan-Run; Hua, Tian-Xiang; Wu, Gui-Tong; He, Chao-Sheng; Zhang, Ye

    2014-11-01

    Combining the idea of ping-pong protocol with Controlled-NOT operation, we propose a secure quantum dialogue protocol based on single-photonss. Bob obtains the information of the encrypted quantum state by performing Controlled-NOT operation on the auxiliary particle and the encrypted single-photonss. Unlike the previous quantum dialogue protocols based on single-photonss, the proposed protocol not only overcomes information leakage but also possesses an acceptable efficiency.

  10. CO2 leakage risk in 3D heterogeneous formations

    NASA Astrophysics Data System (ADS)

    Hou, Z.; Murray, C. J.; Rockhold, M. L.

    2011-12-01

    In this study we use a stochastic sensitivity analysis framework to evaluate the impact of 3D spatial heterogeneity in permeability on CO2 leakage risk. The leakage is defined as the total mass of CO2 moving into the overburden through the caprock-overburden interface, in both gaseous and liquid (dissolved) phases. The entropy-based framework has the ability to quantify the uncertainty associated with the input parameters/factors in the form of prior pdfs (probability density functions). Effective sampling of the prior pdfs enables us to explore the parameter space and systematically evaluate the individual and combined effects of the factors/parameters of interest on CO2 leakage risk. The parameters that are considered in the study include: mean, variance, and horizontal to vertical spatial anisotropy ratio for caprock permeability, and those same parameters for reservoir permeability. Given the sampled spatial variogram parameters, multiple realizations of permeability fields were generated using GSLIB subroutines. For each permeability field, a numerical simulator STOMP (water-salt-CO2-energy operational mode) is used to simulate the CO2 migration within the reservoir and caprock up to 50 years after injection. Due to intensive computational demand, a scalable version simulator, eSTOMP, is run on the Jaguar supercomputer. We then perform statistical analyses and summarize the relationships between the parameters of interest (mean/variance/anisotropy ratio of caprock/reservoir permeability) and CO2 leakage ratio. We will also present the effects of those parameters on CO2 plume radius and reservoir injectivity.

  11. Tension-induced pore formation and leakage in adhering vesicles

    NASA Astrophysics Data System (ADS)

    Lenz, P.; Johnson, J. M.; Chan, Y.-H. M.; Boxer, S. G.

    2006-08-01

    The influence of inclusion-induced tension on pore formation is studied theoretically and experimentally. It is shown that fluorescently labeled lipids can enhance pore formation and induce leakage of adhering vesicles. These effects are more pronounced for smaller vesicles. The theoretical predictions are confirmed by experimental two-color fluorescent data. Finally, the influence of the pore formation dynamics on rupture processes of vesicles is analyzed yielding a new picture of the transition to bilayer disks.

  12. Magnetic flux leakage modeling for mechanical damage in transmission pipelines

    SciTech Connect

    Ivanov, P.A.; Zhang, Z.; Yeoh, C.H.; Udpa, L.; Sun, Y.; Udpa, S.S.; Lord, W.

    1998-09-01

    This paper presents a two stage FE model for prediction of magnetic flux leakage, resulting from mechanical damage. In the first stage the stress distribution associated with mechanical damage is obtained from a structural model. In the second stage the stress distribution is incorporated into a magnetic FE model, by mapping stress levels to permeability. MFL signals are calculated and compared with experimental gouge MFL signatures.

  13. Gas Turbine Tip Region Leakage Flow and Heat Transfer

    DTIC Science & Technology

    2005-09-07

    overlapped with a color map of scalar SMOKE VISULIZATION magnitudes, which are divided by the cascade exit velocity, in Smoke visualization was carried out...34Rotor-Tip Leakage: Part I - Basic Methodology," pressure on the over-tip casing wall of an axial turbine ASME Journal of Engineering for Power, Vol. 104...blade was compared with results ofwerewrapedarond rofledribs Th tet badedifers Durham University and revealed excellent match, assuring thefrom the

  14. Using Biomineralization Sealing for Leakage Mitigation in Shale

    NASA Astrophysics Data System (ADS)

    Gerlach, R.; Rothman, A.; Hiebert, R.; Cunningham, A. B.

    2013-12-01

    Estimates of the number of abandoned wells in the U.S and abroad range in the millions, all of which have a high probability of leaking at some point during their lifetime. We are currently focusing on developing technologies for sealing unwanted leakage pathways in fractured shales. We are investigating the feasibility of a plugging technology, which is based on the microbially-induced precipitation of carbonate minerals. Microbes can hydrolyze urea to ultimately change the saturation state of various minerals, including carbonates, such as calcium carbonate. The resulting biocement (calcium carbonate) has been demonstrated by us to cement together heavily fractured shale and drastically reduce the permeability of fractures in shale cores. We propose this technology for mitigating leakage from abandoned wells and as an alternative to more traditional, cement-based plugging technologies. We have demonstrated the principal feasibility of this technology for ensuring geologic CO2 storage in deep saline aquifers through the plugging of small aperture leaks such as fractures or delamination interfaces in the vicinity of injection wells. Fractured shale might reduce production efficiency as well as pose a risk to the environment due to leakage of hydrocarbons in the form of gas and liquid. The biomineralization technology can be delivered via low viscosity fluids and could potentially have significant advantages including a time- and space-dependent placement of biocement plugs in the immediate vicinity of wells as well as further away from the wellbore in the rock formation.

  15. Surface Leakage Mechanisms in III-V Infrared Barrier Detectors

    NASA Astrophysics Data System (ADS)

    Sidor, D. E.; Savich, G. R.; Wicks, G. W.

    2016-09-01

    Infrared detector epitaxial structures employing unipolar barriers exhibit greatly reduced dark currents compared to simple pn-based structures. When correctly positioned within the structure, unipolar barriers are highly effective at blocking bulk dark current mechanisms. Unipolar barriers are also effective at suppressing surface leakage current in infrared detector structures employing absorbing layers that possess the same conductivity type in their bulk and at their surface. When an absorbing layer possesses opposite conductivity types in its bulk and at its surface, unipolar barriers are not solutions to surface leakage. This work reviews empirically determined surface band alignments of III-V semiconductor compounds and modeled surface band alignments of both gallium-free and gallium-containing type-II strained layer superlattice material systems. Surface band alignments are used to predict surface conductivity types in several detector structures, and the relationship between surface and bulk conductivity types in the absorbing layers of these structures is used as the basis for explaining observed surface leakage characteristics.

  16. Air Leakage and Air Transfer Between Garage and Living Space

    SciTech Connect

    Rudd, Armin

    2014-09-01

    This research project focused on evaluation of air transfer between the garage and living space in a single-family detached home constructed by a production homebuilder in compliance with the 2009 International Residential Code and the 2009 International Energy Conservation Code. The project gathered important information about the performance of whole-building ventilation systems and garage ventilation systems as they relate to minimizing flow of contaminated air from garage to living space. A series of 25 multi-point fan pressurization tests and additional zone pressure diagnostic testing characterized the garage and house air leakage, the garage-to-house air leakage, and garage and house pressure relationships to each other and to outdoors using automated fan pressurization and pressure monitoring techniques. While the relative characteristics of this house may not represent the entire population of new construction configurations and air tightness levels (house and garage) throughout the country, the technical approach was conservative and should reasonably extend the usefulness of the results to a large spectrum of house configurations from this set of parametric tests in this one house. Based on the results of this testing, the two-step garage-to-house air leakage test protocol described above is recommended where whole-house exhaust ventilation is employed.

  17. Indoor-Outdoor Air Leakage of Apartments and Commercial Buildings

    SciTech Connect

    Price, P.N.; Shehabi, A.; Chan, R.W.; Gadgil, A.J.

    2006-06-01

    We compiled and analyzed available data concerning indoor-outdoor air leakage rates and building leakiness parameters for commercial buildings and apartments. We analyzed the data, and reviewed the related literature, to determine the current state of knowledge of the statistical distribution of air exchange rates and related parameters for California buildings, and to identify significant gaps in the current knowledge and data. Very few data were found from California buildings, so we compiled data from other states and some other countries. Even when data from other developed countries were included, data were sparse and few conclusive statements were possible. Little systematic variation in building leakage with construction type, building activity type, height, size, or location within the u.s. was observed. Commercial buildings and apartments seem to be about twice as leaky as single-family houses, per unit of building envelope area. Although further work collecting and analyzing leakage data might be useful, we suggest that a more important issue may be the transport of pollutants between units in apartments and mixed-use buildings, an under-studied phenomenon that may expose occupants to high levels of pollutants such as tobacco smoke or dry cleaning fumes.

  18. Oil Leakage from the Seal Ring of a Scroll Compressor

    NASA Astrophysics Data System (ADS)

    Kobayashi, Naoki; Fukui, Atsushi; Horiguchi, Hironori; Tsujimoto, Yoshinobu; Toyama, Toshiyuki

    In scroll compressors for air conditioners, there is a compressor with back-pressure chamber spaced by seal ring behind orbiting scroll. High pressure in the backpressure chamber presses the orbiting scroll to fixed scroll. In the case that lubrication oil and refrigerant gas with high pressure and temperature in the backpressure chamber leak to low pressure chamber through the seal ring, the efficiency of compressor decreases and the oil circulation rate can increase. In the present study the leakage characteristics of lubrication oil from the backpressure chamber to the low pressure chamber were investigated. In experiment, it was found that the oil leakage is larger for higher rotational speed of rotating disk, higher viscosity of oil and smaller pressure difference between the backpressure and low-pressure chambers. This could be explained by the calculation in which the seal ring was assumed to have a tilt angle. It was also found in the calculation that oil leakage is larger due to the thicker oil film between the seal ring and the rotating disk in the case of higher rotational speed of the disk, higher viscosity of oil and smaller pressure difference between the backpressure and low-pressure chambers.

  19. The effect of photodynamic action on leakage of ions through liposomal membranes that contain oxidatively modified lipids.

    PubMed

    Ytzhak, Shany; Ehrenberg, Benjamin

    2014-01-01

    Singlet oxygen, created in photosensitization, peroxidizes unsaturated fatty acids of the membrane's lipids. This generates alcoholic or aldehyde groups at double bonds' breakage points. In a previous study, we examined the leakage of a K(+) -induced cross-membrane electric potential of liposomes that undergo photosensitization. The question remains to what extent peroxidized lipids can compromise the stability of the membrane. In this study, we studied the effect of the oxidatively modified lipids PGPC and ALDOPC in the membrane on its stability, by monitoring the membrane electric potential with the potentiometric dye DiSC(2)(5). As the content of the modified lipids increases the membrane becomes less stable, and even at just 2% of the modified lipids the membrane's integrity is affected, in respect to the leakage of ions through it. When the liposomes that contain the modified lipids undergo photosensitization by hematoporphyrin, the lipid bilayer becomes even more unstable and passage of ions is accelerated. We conclude that the existence of lipids with a shortened fatty acid that is terminated by a carboxylic acid or an aldehyde and more so when photosensitized damage occurs to unsaturated fatty acids in lecithin, add up to a critical alteration of the membrane, which becomes leaky to ions.

  20. Availability: A Metric for Nucleic Acid Strand Displacement Systems

    PubMed Central

    2016-01-01

    DNA strand displacement systems have transformative potential in synthetic biology. While powerful examples have been reported in DNA nanotechnology, such systems are plagued by leakage, which limits network stability, sensitivity, and scalability. An approach to mitigate leakage in DNA nanotechnology, which is applicable to synthetic biology, is to introduce mismatches to complementary fuel sequences at key locations. However, this method overlooks nuances in the secondary structure of the fuel and substrate that impact the leakage reaction kinetics in strand displacement systems. In an effort to quantify the impact of secondary structure on leakage, we introduce the concepts of availability and mutual availability and demonstrate their utility for network analysis. Our approach exposes vulnerable locations on the substrate and quantifies the secondary structure of fuel strands. Using these concepts, a 4-fold reduction in leakage has been achieved. The result is a rational design process that efficiently suppresses leakage and provides new insight into dynamic nucleic acid networks. PMID:26875531

  1. Multiple hypothesis tracking for the cyber domain

    NASA Astrophysics Data System (ADS)

    Schwoegler, Stefan; Blackman, Sam; Holsopple, Jared; Hirsch, Michael J.

    2011-09-01

    This paper discusses how methods used for conventional multiple hypothesis tracking (MHT) can be extended to domain-agnostic tracking of entities from non-kinematic constraints such as those imposed by cyber attacks in a potentially dense false alarm background. MHT is widely recognized as the premier method to avoid corrupting tracks with spurious data in the kinematic domain but it has not been extensively applied to other problem domains. The traditional approach is to tightly couple track maintenance (prediction, gating, filtering, probabilistic pruning, and target confirmation) with hypothesis management (clustering, incompatibility maintenance, hypothesis formation, and Nassociation pruning). However, by separating the domain specific track maintenance portion from the domain agnostic hypothesis management piece, we can begin to apply the wealth of knowledge gained from ground and air tracking solutions to the cyber (and other) domains. These realizations led to the creation of Raytheon's Multiple Hypothesis Extensible Tracking Architecture (MHETA). In this paper, we showcase MHETA for the cyber domain, plugging in a well established method, CUBRC's INFormation Engine for Real-time Decision making, (INFERD), for the association portion of the MHT. The result is a CyberMHT. We demonstrate the power of MHETA-INFERD using simulated data. Using metrics from both the tracking and cyber domains, we show that while no tracker is perfect, by applying MHETA-INFERD, advanced nonkinematic tracks can be captured in an automated way, perform better than non-MHT approaches, and decrease analyst response time to cyber threats.

  2. Importance of the PMMA viscoelastic rheology on the reduction of the leakage risk during osteoporotic bone augmentation: A numerical leakage model through a porous media.

    PubMed

    Alenezi, Salem; Jerban, Saeed; Elkoun, Saïd

    2017-01-01

    Osteoporotic fractures poses one of the most problematic health issues that affects millions of people by weakening their bones (Osteoporosis). Polymethylmethacrylate (PMMA) cement is usually used to augment the bone and stabilize the fractures. Despite the benefit of using PMMA, it might cause a leakage where the cement undesirably access the surrounding tissues or vessels and lead to a serious complications. Consequently, it is important to study the leakage phenomenon and associated geometric and operation interactions. Although the experimental leakage models have been reported in many studies, a representative numerical leakage model is not exist. Therefore, the objectives of the present paper are to: (a) to develop and validate a representative numerical leakage model; and (b) to investigate numerically and analytically the importance of the rheological parameters (viscosity and relaxation time) on the cement flow to reduce the risk of leakage. ANSYS Polyflow was utilized to implement a 2D numerical leakage model to study the interaction of complex rheological parameters of the cement with the operational and geometrical structure of the representative porous media. In this model, the cement (represented by the upper-convected Maxwell model) flows from the entrance (tip of an 8 gauge cannula) through a porous media with a leakage path (blood vessels) toward the output (Bottom side). The verified and validated numerical leakage model showed the importance of the elastic and viscous part of the cement to control the uniformity of the distributed cement and augmentation pressure, respectively. Moreover, increasing the flow rate can lead to reduce the risk of leakage since the elastic effect will increase. Geometrical parameters of the porous media has a minor effect on changing the elasticity and subsequently on the uniformity of the distributed cement. In conclusion, Cement rheological parameters are found to be the most influential parameters to reduce the

  3. Micro-leakage of a Fissure Sealant Cured Using Quartz-tungsten-halogen and Plasma Arc Light Curing Units

    PubMed Central

    Bahrololoomi, Zahra; Soleimani, Ali Asghar; Jafari, Najmeh; Varkesh, Bentolhoda

    2014-01-01

    Background and aims. Newer curing units such as plasma arc can polymerize the sealants in much shorter curing times. The aim of this study was to compare the effect of two different curing units on the micro-leakage of a fissure sealant material. Materials and methods. Sixty two extracted premolars without caries were randomly divided into two groups of 31 samples. Occlusal surfaces of all teeth were cleansed. Then, teeth surfaces were etched by 37% phosphoric acid. After rinsing and drying, occlusal surfaces of teeth were sealed by a fissure sealant. The sealant was then cured using either a halogen light curing unit or a plasma arc curing light. After sealing, the teeth were thermocycled for 500 cycles. The teeth were then sectioned and examined for micro-leakage. Statistical analyses were performed with Mann-Whitney test. Results. There was no significant difference between two groups regarding micro-leakage (P = 0.42). Conclusion. Results showed that there was no significant difference between two different curing units. Therefore, plasma arc unit might be a useful alternative for sealant polymerization. PMID:25587389

  4. Micro-leakage of a Fissure Sealant Cured Using Quartz-tungsten-halogen and Plasma Arc Light Curing Units.

    PubMed

    Bahrololoomi, Zahra; Soleimani, Ali Asghar; Jafari, Najmeh; Varkesh, Bentolhoda

    2014-01-01

    Background and aims. Newer curing units such as plasma arc can polymerize the sealants in much shorter curing times. The aim of this study was to compare the effect of two different curing units on the micro-leakage of a fissure sealant material. Materials and methods. Sixty two extracted premolars without caries were randomly divided into two groups of 31 samples. Occlusal surfaces of all teeth were cleansed. Then, teeth surfaces were etched by 37% phosphoric acid. After rinsing and drying, occlusal surfaces of teeth were sealed by a fissure sealant. The sealant was then cured using either a halogen light curing unit or a plasma arc curing light. After sealing, the teeth were thermocycled for 500 cycles. The teeth were then sectioned and examined for micro-leakage. Statistical analyses were performed with Mann-Whitney test. Results. There was no significant difference between two groups regarding micro-leakage (P = 0.42). Conclusion. Results showed that there was no significant difference between two different curing units. Therefore, plasma arc unit might be a useful alternative for sealant polymerization.

  5. Prevention of biliary leakage after partial liver resection using topical hemostatic agents.

    PubMed

    Erdogan, Deha; Busch, Olivier R C; Gouma, Dirk J; van Gulik, Thomas M

    2007-01-01

    Liver resection is widely accepted as the only potentially curative treatment in malignant or benign hepatobiliary lesions. Although not frequent, biliary leakage is a postoperative complication which may have considerable consequences. The field of topical hemostatic agents is rapidly developing, with various products currently available. This article reviews the risk factors associated with biliary leakage and the methods used for testing or prevention of biliary leakage. A literature search was performed using key words related to experimental and clinical studies dealing with biliary leakage. Experimental studies assessed the potential bilio-static effect of different topical hemostatic agents after bile duct reconstruction. Clinical series show biliary leakage rates up to 12%. There is no evidence that flushing of the bile duct system after resection reduces the incidence of biliary leakage. Further controlled studies are needed to clarify the preventive effect of topical hemostatic agents on biliary leakage after liver resection.

  6. Automated detection of leakage in fluorescein angiography images with application to malarial retinopathy.

    PubMed

    Zhao, Yitian; MacCormick, Ian J C; Parry, David G; Leach, Sophie; Beare, Nicholas A V; Harding, Simon P; Zheng, Yalin

    2015-06-01

    The detection and assessment of leakage in retinal fluorescein angiogram images is important for the management of a wide range of retinal diseases. We have developed a framework that can automatically detect three types of leakage (large focal, punctate focal, and vessel segment leakage) and validated it on images from patients with malarial retinopathy. This framework comprises three steps: vessel segmentation, saliency feature generation and leakage detection. We tested the effectiveness of this framework by applying it to images from 20 patients with large focal leak, 10 patients with punctate focal leak, and 5,846 vessel segments from 10 patients with vessel leakage. The sensitivity in detecting large focal, punctate focal and vessel segment leakage are 95%, 82% and 81%, respectively, when compared to manual annotation by expert human observers. Our framework has the potential to become a powerful new tool for studying malarial retinopathy, and other conditions involving retinal leakage.

  7. Automated Detection of Leakage in Fluorescein Angiography Images with Application to Malarial Retinopathy

    PubMed Central

    Zhao, Yitian; J. C. MacCormick, Ian; G. Parry, David; Leach, Sophie; A. V. Beare, Nicholas; P. Harding, Simon; Zheng, Yalin

    2015-01-01

    The detection and assessment of leakage in retinal fluorescein angiogram images is important for the management of a wide range of retinal diseases. We have developed a framework that can automatically detect three types of leakage (large focal, punctate focal, and vessel segment leakage) and validated it on images from patients with malarial retinopathy. This framework comprises three steps: vessel segmentation, saliency feature generation and leakage detection. We tested the effectiveness of this framework by applying it to images from 20 patients with large focal leak, 10 patients with punctate focal leak, and 5,846 vessel segments from 10 patients with vessel leakage. The sensitivity in detecting large focal, punctate focal and vessel segment leakage are 95%, 82% and 81%, respectively, when compared to manual annotation by expert human observers. Our framework has the potential to become a powerful new tool for studying malarial retinopathy, and other conditions involving retinal leakage. PMID:26030010

  8. Amative orientation: the hormonal hypothesis examined.

    PubMed

    Money, John

    2002-01-01

    The hypothesis that human male and female amative orientation, arousal and courtship are sex-hormone dependent had as its precursor John Hunter's recorded but unpublished 18th century experiments of cross-sexed gonadal transplants in chicks. The hypothesis gained momentum in the 20th century after the discovery and eventual marketing of the sex hormones, and after the experimental demonstration by William C. Young that, in guinea-pigs, cross-sexed hormone administered prenatally influenced their subsequent male/female courtship and mating behavior. Comparatively and in review, human clinical syndromes of hypermasculinization and hypomasculinization do not disconfirm the hormonal hypothesis, but they do not adequately confirm it, either. They are compatible with the idea of a cofactor that governs whether amative orientation in practice, ideation and imagery is homosexual, heterosexual or bisexual.

  9. Monetizing Leakage Risk of Geologic CO2 Storage using Wellbore Permeability Frequency Distributions

    NASA Astrophysics Data System (ADS)

    Bielicki, Jeffrey; Fitts, Jeffrey; Peters, Catherine; Wilson, Elizabeth

    2013-04-01

    Carbon dioxide (CO2) may be captured from large point sources (e.g., coal-fired power plants, oil refineries, cement manufacturers) and injected into deep sedimentary basins for storage, or sequestration, from the atmosphere. This technology—CO2 Capture and Storage (CCS)—may be a significant component of the portfolio of technologies deployed to mitigate climate change. But injected CO2, or the brine it displaces, may leak from the storage reservoir through a variety of natural and manmade pathways, including existing wells and wellbores. Such leakage will incur costs to a variety of stakeholders, which may affect the desirability of potential CO2 injection locations as well as the feasibility of the CCS approach writ large. Consequently, analyzing and monetizing leakage risk is necessary to develop CCS as a viable technological option to mitigate climate change. Risk is the product of the probability of an outcome and the impact of that outcome. Assessment of leakage risk from geologic CO2 storage reservoirs requires an analysis of the probabilities and magnitudes of leakage, identification of the outcomes that may result from leakage, and an assessment of the expected economic costs of those outcomes. One critical uncertainty regarding the rate and magnitude of leakage is determined by the leakiness of the well leakage pathway. This leakiness is characterized by a leakage permeability for the pathway, and recent work has sought to determine frequency distributions for the leakage permeabilities of wells and wellbores. We conduct a probabilistic analysis of leakage and monetized leakage risk for CO2 injection locations in the Michigan Sedimentary Basin (USA) using empirically derived frequency distributions for wellbore leakage permeabilities. To conduct this probabilistic risk analysis, we apply the RISCS (Risk Interference of Subsurface CO2 Storage) model (Bielicki et al, 2013a, 2012b) to injection into the Mt. Simon Sandstone. RISCS monetizes leakage risk

  10. Ethanol-Induced Leakage in Saccharomyces cerevisiae: Kinetics and Relationship to Yeast Ethanol Tolerance and Alcohol Fermentation Productivity.

    PubMed

    Salgueiro, S P; Sá-Correia, I; Novais, J M

    1988-04-01

    Ethanol stimulated the leakage of amino acids and 260-nm-light-absorbing compounds from cells of Saccharomyces cerevisiae. The efflux followed first-order kinetics over an initial period. In the presence of lethal concentrations of ethanol, the efflux rates at 30 and 36 degrees C were an exponential function of ethanol concentration: k(e) = k(e)e, where k(e) and k(e) are the efflux rate constants, respectively, in the presence of a concentration X of ethanol or the minimal concentration of ethanol, X(m), above which the equation was applicable, coincident with the minimal lethal concentration of ethanol. E is the enhancement constant. At 36 degrees C, as compared with the corresponding values at 30 degrees C, the efflux rates were higher and the minimal concentration of ethanol (X(m)) was lower. The exponential constants for the enhancement of the rate of leakage (E) had similar values at 30 or 36 degrees C and were of the same order of magnitude as the corresponding exponential constants for ethanol-induced death. Under isothermic conditions (30 degrees C) and up to 22% (vol/vol) ethanol, the resistance to ethanol-induced leakage of 260-nm-light-absorbing compounds was found to be closely related with the ethanol tolerance of three strains of yeasts, Kluyveromyces marxianus, Saccharomyces cerevisiae, and Saccharomyces bayanus. The resistance to ethanol-induced leakage indicates the possible adoption of the present method for the rapid screening of ethanol-tolerant strains. The addition to a fermentation medium of the intracellular material obtained by ethanol permeabilization of yeast cells led to improvements in alcohol fermentation by S. cerevisiae and S. bayanus. The action of the intracellular material, by improving yeast ethanol tolerance, and the advantages of partially recycling the fermented medium after distillation were discussed.

  11. Ethanol-Induced Leakage in Saccharomyces cerevisiae: Kinetics and Relationship to Yeast Ethanol Tolerance and Alcohol Fermentation Productivity

    PubMed Central

    Salgueiro, Sancha P.; Sá-Correia, Isabel; Novais, Júlio M.

    1988-01-01

    Ethanol stimulated the leakage of amino acids and 260-nm-light-absorbing compounds from cells of Saccharomyces cerevisiae. The efflux followed first-order kinetics over an initial period. In the presence of lethal concentrations of ethanol, the efflux rates at 30 and 36°C were an exponential function of ethanol concentration: keX = keXmeE (X-Xm), where keX and keXm are the efflux rate constants, respectively, in the presence of a concentration X of ethanol or the minimal concentration of ethanol, Xm, above which the equation was applicable, coincident with the minimal lethal concentration of ethanol. E is the enhancement constant. At 36°C, as compared with the corresponding values at 30°C, the efflux rates were higher and the minimal concentration of ethanol (Xm) was lower. The exponential constants for the enhancement of the rate of leakage (E) had similar values at 30 or 36°C and were of the same order of magnitude as the corresponding exponential constants for ethanol-induced death. Under isothermic conditions (30°C) and up to 22% (vol/vol) ethanol, the resistance to ethanol-induced leakage of 260-nm-light-absorbing compounds was found to be closely related with the ethanol tolerance of three strains of yeasts, Kluyveromyces marxianus, Saccharomyces cerevisiae, and Saccharomyces bayanus. The resistance to ethanol-induced leakage indicates the possible adoption of the present method for the rapid screening of ethanol-tolerant strains. The addition to a fermentation medium of the intracellular material obtained by ethanol permeabilization of yeast cells led to improvements in alcohol fermentation by S. cerevisiae and S. bayanus. The action of the intracellular material, by improving yeast ethanol tolerance, and the advantages of partially recycling the fermented medium after distillation were discussed. PMID:16347612

  12. The effect of heterogeneity identifying the leakage of carbon dioxide in a shallow aquifer: an experimental study

    NASA Astrophysics Data System (ADS)

    Ha, S. W.; Lee, S. H.; Jeon, W. T.; Joo, Y. J.; Lee, K. K.

    2014-12-01

    Carbon dioxide (CO2) leakage into the shallow aquifer is one of the main concerns at a CO2 sequestration site. Various hydrogeochemical parameters have been suggested to determine the leakage (i.e., pH, EC, Alkalinity, Ca and δ13C). For the practical point of view, direct and continuous measurement of the dissolved CO2 concentration at the proper location can be the most useful strategy for the CO2 leakage detection in a shallow aquifer. In order to enhance possibility of identifying leaked CO2, monitoring location should be determined with regard to the shallow aquifer heterogeneity. In this study, a series of experiments were conducted to investigate the effects of heterogeneity on the dissolved CO2 concentrations. A 2-D sand tank of homogeneous medium sands including a single heterogeneity layer was designed. Two NDIR CO2 sensors, modified for continuous measuring in aquatic system, were installed above and below the single heterogeneous layer (clay, fine and medium sand lenses). Also, temperature and water contents were measured continuously at a same position. Bromocresol purple which is one of the acid-base indicator was used to visualize CO2 migration. During the gas phase CO2 injection at the bottom of the sand tank, dissolved CO2 in the water is continuously measured. In the results, significant differences of concentrations were observed due to the presence of heterogeneity layer, even the locations were close. These results suggested that monitoring location should be determined considering vertical heterogeneity of shallow aquifer at a CO2 leakage site.

  13. Exploiting multi-proxy analysis of marine sediments in the southeast Atlantic: Intensification of Agulhas leakage tied to the start of the 100ka cycles.

    NASA Astrophysics Data System (ADS)

    Petrick, Benjamin; McClymont, Erin; Marret, Fabienne

    2013-04-01

    The transition in orbital forcing from a 41 ka world to a 100 ka world was a major change in the climate regime over the last 1.5 Ma but its causes and its impacts are still being investigated. Here, we present reconstructions of sea-surface temperature (SST), salinity, and plankton assemblages obtained from a single core, ODP site 1087 (31°28'S, 15°19'E, 1374m water depth) spanning the last 1.5 Ma. Our hypothesis is that the response and position of the Agulhas leakage, which transfers heat and salt to the SE Atlantic region, has shifted as a result of changes in the dominant periodicity of orbital forcing. We draw on evidence from the alkenone (U37K') proxy for SST, dinoflagllate species analysis, and foraminifera oxygen isotopes for salinity and ice volume, to identify changes in the input of the Agulhas leakage to the SE Atlantic. We present the first continuous record of SE Atlantic SSTs reaching to 1.5 Ma which spans both the 41 kyr and 100 kyr glacial cycles. We identify large changes in SST and salinity on glacial-interglacial timescales, but show that there is a consistent pattern of SSTs leading salinity and then global ice volume change, so that deglaciation occurs some 5-10 kyr after the onset of rapid warming in the SE Atlantic during the recent glacials and interglacials. This early warming pattern, which characterizes the most recent cycles, began to develop as early at 900 ka, as the 100 kyr cycles became dominant. Before this time there is little evidence of Agulhas leakage in the ODP1087 record. We also show that over the last 600 ka there has been a strengthening of the Agulhas Leakage which has led to warmer interglacials over this time period. Overall the record shows that the strength and location of the Agulhas leakage is sensitive to changes in the dominant cycles in the climate.

  14. An excitatory synapse hypothesis of depression

    PubMed Central

    Thompson, Scott M.; Kallarackal, Angy J.; Kvarta, Mark D.; Van Dyke, Adam M.; LeGates, Tara A.; Cai, Xiang

    2015-01-01

    Depression is a common cause of mortality and morbidity, but the biological bases of the deficits in emotional and cognitive processing remain incompletely understood. Current antidepressant therapies are effective in only some patients and act slowly. We propose an excitatory synapse hypothesis of depression in which chronic stress and genetic susceptibility cause changes in the strength of subsets of glutamatergic synapses at multiple locations, including the prefrontal cortex, hippocampus and nucleus accumbens, leading to a dysfunction of cortico-mesolimbic reward circuitry that underlies many of the symptoms of depression. This hypothesis accounts for current depression treatments and suggests an updated framework for the development of better therapeutic compounds. PMID:25887240

  15. CO2-Brine Rheology Could Suppress Leakage From Geologic Carbon Sequestration Sites

    NASA Astrophysics Data System (ADS)

    Wang, S.; Clarens, A. F.

    2011-12-01

    Geologic carbon sequestration (GCS) in the deep subsurface is an attractive means for storing large volumes of CO2 over the long term. GCS is predicated on there being minimal leakage of CO2 to the surface since this would negate the climate change benefits and could also create a human health risk. Despite the importance of understanding leakage processes to GCS deployment, the phenomena remain especially difficult to characterize because CO2, driven by buoyant forces out of host formations, must travel over long length scales, encountering varied geologic formations and endogenous brines, and experiencing a wide range of shear, temperature and pressure conditions that result in complex phase behavior. This study explores the rheology of CO2-brine mixtures in an effort to better characterize the geophysics of a rising parcel of CO2 in the subsurface. Experimental work in this area to date has assumed that CO2-brine mixtures will exhibit simple Newtonian behavior. The hypothesis of this work is that CO2-brine mixtures will move through porous media generating high shear rates, caused by the small pore sizes, that could result in more complex flow phenomena. The rheological properties of single and multiphase CO2-brine mixtures were measured over a range of GCS-relevant temperature, pressure, ionic strength, and shear conditions using a rotational rheometer fitted with a high-pressure vessel and a low viscosity measurement unit. Under liquid-liquid equilibrium (LLE) conditions CO2-brine mixtures were found to exhibit consistently Newtonian behavior with the effective viscosity generally increasing with respect to CO2(aq) concentration. A small dip in viscosity occurs at the pressure corresponding to the transition of CO2 from liquid to gas but this minor effect is not likely to have an appreciable impact on leakage rates. More significantly, under vapor-liquid equilibrium (VLE) conditions, CO2-brine suspensions exhibit complex viscoelastic behavior that could

  16. Air Leakage and Air Transfer Between Garage and Living Space

    SciTech Connect

    Rudd, A.

    2014-09-01

    This research project focused on evaluation of air transfer between the garage and living space in a single-family detached home constructed by a production homebuilder in compliance with the 2009 International Residential Code and the 2009 International Energy Conservation Code. The project gathered important information about the performance of whole-building ventilation systems and garage ventilation systems as they relate to minimizing flow of contaminated air from garage to living space. A series of 25 multi-point fan pressurization tests and additional zone pressure diagnostic testing characterized the garage and house air leakage, the garage-to-house air leakage, and garage and house pressure relationships to each other and to outdoors using automated fan pressurization and pressure monitoring techniques. While the relative characteristics of this house may not represent the entire population of new construction configurations and air tightness levels (house and garage) throughout the country, the technical approach was conservative and should reasonably extend the usefulness of the results to a large spectrum of house configurations from this set of parametric tests in this one house. Based on the results of this testing, the two-step garage-to-house air leakage test protocol described above is recommended where whole-house exhaust ventilation is employed. For houses employing whole-house supply ventilation (positive pressure) or balanced ventilation (same pressure effect as the Baseline condition), adherence to the EPA Indoor airPLUS house-to-garage air sealing requirements should be sufficient to expect little to no garage-to-house air transfer.

  17. Power Beaming Leakage Radiation as a SETI Observable

    NASA Astrophysics Data System (ADS)

    Benford, James N.; Benford, Dominic J.

    2016-07-01

    The most observable leakage radiation from an advanced civilization may well be from the use of power beaming to transfer energy and accelerate spacecraft. Applications suggested for power beaming involve launching spacecraft to orbit, raising satellites to a higher orbit, and interplanetary concepts involving space-to-space transfers of cargo or passengers. We also quantify beam-driven launch to the outer solar system, interstellar precursors, and ultimately starships. We estimate the principal observable parameters of power beaming leakage. Extraterrestrial civilizations would know their power beams could be observed, and so could put a message on the power beam and broadcast it for our receipt at little additional energy or cost. By observing leakage from power beams we may find a message embedded on the beam. Recent observations of the anomalous star KIC 8462852 by the Allen Telescope Array (ATA) set some limits on extraterrestrial power beaming in that system. We show that most power beaming applications commensurate with those suggested for our solar system would be detectable if using the frequency range monitored by the ATA, and so the lack of detection is a meaningful, if modest, constraint on extraterrestrial power beaming in that system. Until more extensive observations are made, the limited observation time and frequency coverage are not sufficiently broad in frequency and duration to produce firm conclusions. Such beams would be visible over large interstellar distances. This implies a new approach to the SETI search: instead of focusing on narrowband beacon transmissions generated by another civilization, look for more powerful beams with much wider bandwidth. This requires a new approach for their discovery by telescopes on Earth. Further studies of power beaming applications should be performed, potentially broadening the parameter space of the observable features that we have discussed here.

  18. Assessment of different dyes used in leakage studies.

    PubMed

    Mente, Johannes; Ferk, Stephan; Dreyhaupt, Jens; Deckert, Andreas; Legner, Milos; Staehle, Hans Joerg

    2010-06-01

    The goal of this in vitro study was to identify the most suitable dye for endodontic dye leakage studies, which could be a further step towards standardisation. The root canals of 70 extracted, single-rooted human adult teeth were enlarged to apical size 50 using hand instruments. The teeth were divided into seven groups (n = 10 each), and all root canals were completely filled by injection with one of the following dyes: methylene blue 0.5% and 5%, blue ink, black ink, eosin 5%, basic fuchsin 0.5% and drawing ink. Transverse root sections from the coronal, middle and apical part of the roots were examined, and the percentage of the dentine penetrated by dye was evaluated by software-supported light microscopy. In addition, the range of particle size of drawing ink particles was evaluated. There were conspicuous differences in the relative dye penetration into the root dentine and the penetration behaviour in the different root sections (two-way ANOVA, both p < 0.0001). One dye (drawing ink) penetrated less into the root dentine compared with all the others (p <0.0001). The particle size of this agent (0.1-2 microm) corresponds best with the size range of a representative selection of 21 species of pathogenic endodontic bacteria. Compared to the other dyes tested, drawing ink appears to be superior for use in endodontic dye leakage studies. The penetration behaviour into the root dentine of all the other dyes tested might be one factor that limits the applicability of these dyes in dye leakage studies.

  19. Impeller leakage flow modeling for mechanical vibration control

    NASA Technical Reports Server (NTRS)

    Palazzolo, Alan B.

    1996-01-01

    HPOTP and HPFTP vibration test results have exhibited transient and steady characteristics which may be due to impeller leakage path (ILP) related forces. For example, an axial shift in the rotor could suddenly change the ILP clearances and lengths yielding dynamic coefficient and subsequent vibration changes. ILP models are more complicated than conventional-single component-annular seal models due to their radial flow component (coriolis and centrifugal acceleration), complex geometry (axial/radial clearance coupling), internal boundary (transition) flow conditions between mechanical components along the ILP and longer length, requiring moment as well as force coefficients. Flow coupling between mechanical components results from mass and energy conservation applied at their interfaces. Typical components along the ILP include an inlet seal, curved shroud, and an exit seal, which may be a stepped labyrinth type. Von Pragenau (MSFC) has modeled labyrinth seals as a series of plain annular seals for leakage and dynamic coefficient prediction. These multi-tooth components increase the total number of 'flow coupled' components in the ILP. Childs developed an analysis for an ILP consisting of a single, constant clearance shroud with an exit seal represented by a lumped flow-loss coefficient. This same geometry was later extended to include compressible flow. The objective of the current work is to: supply ILP leakage-force impedance-dynamic coefficient modeling software to MSFC engineers, base on incompressible/compressible bulk flow theory; design the software to model a generic geometry ILP described by a series of components lying along an arbitrarily directed path; validate the software by comparison to available test data, CFD and bulk models; and develop a hybrid CFD-bulk flow model of an ILP to improve modeling accuracy within practical run time constraints.

  20. The Hypothesis of Incommensurability and Multicultural Education

    ERIC Educational Resources Information Center

    McDonough, Tim

    2009-01-01

    This article describes the logical and rhetorical grounds for a multicultural pedagogy that teaches students the knowledge and skills needed to interact creatively in the public realm betwixt and between cultures. I begin by discussing the notion of incommensurability. I contend that this hypothesis was intended to perform a particular rhetorical…

  1. Morbidity and Infant Development: A Hypothesis.

    ERIC Educational Resources Information Center

    Pollitt, Ernesto

    1983-01-01

    Results of a study conducted in 14 villages of Sui Lin Township, Taiwan, suggest the hypothesis that, under conditions of extreme economic impoverishment and among children within populations where energy protein malnutrition is endemic, there is an inverse relationship between incidence of morbidity in infancy and measures of motor and mental…

  2. Groupthink: Hypothesis in Need of Testing.

    ERIC Educational Resources Information Center

    Moorhead, Gregory

    1982-01-01

    Reviews the major tenets of the groupthink hypothesis of Irving Janis, as well as the research on which it is based. Reviews previous research on group dynamics related to groupthink. Proposes guidelines for research to test the propositions of groupthink. (Author/RC)

  3. Diagnostic Hypothesis Generation and Human Judgment

    ERIC Educational Resources Information Center

    Thomas, Rick P.; Dougherty, Michael R.; Sprenger, Amber M.; Harbison, J. Isaiah

    2008-01-01

    Diagnostic hypothesis-generation processes are ubiquitous in human reasoning. For example, clinicians generate disease hypotheses to explain symptoms and help guide treatment, auditors generate hypotheses for identifying sources of accounting errors, and laypeople generate hypotheses to explain patterns of information (i.e., data) in the…

  4. Hypothesis on the nature of atmospheric UFOs

    NASA Astrophysics Data System (ADS)

    Mukharev, L. A.

    1991-08-01

    A hypothesis is developed according to which the atmospheric UFO phenomenon has an electromagnetic nature. It is suggested that an atmospheric UFO is an agglomeration of charged atmospheric dust within which there exists a slowly damped electromagnetic field. This field is considered to be the source of the observed optical effects and the motive force of the UFO.

  5. Improving your Hypothesis Testing: Determining Sample Sizes.

    ERIC Educational Resources Information Center

    Luftig, Jeffrey T.; Norton, Willis P.

    1982-01-01

    This article builds on an earlier discussion of the importance of the Type II error (beta) and power to the hypothesis testing process (CE 511 484), and illustrates the methods by which sample size calculations should be employed so as to improve the research process. (Author/CT)

  6. Forty Years Later: Updating the Fossilization Hypothesis

    ERIC Educational Resources Information Center

    Han, ZhaoHong

    2013-01-01

    A founding concept in second language acquisition (SLA) research, fossilization has been fundamental to understanding second language (L2) development. The Fossilization Hypothesis, introduced in Selinker's seminal text (1972), has thus been one of the most influential theories, guiding a significant bulk of SLA research for four decades; 2012…

  7. In Defense of Chi's Ontological Incompatibility Hypothesis

    ERIC Educational Resources Information Center

    Slotta, James D.

    2011-01-01

    This article responds to an article by A. Gupta, D. Hammer, and E. F. Redish (2010) that asserts that M. T. H. Chi's (1992, 2005) hypothesis of an "ontological commitment" in conceptual development is fundamentally flawed. In this article, I argue that Chi's theoretical perspective is still very much intact and that the critique offered by Gupta…

  8. The Marathon Group Hypothesis: An Unanswered Question

    ERIC Educational Resources Information Center

    Marks, Stephen E.; And Others

    1973-01-01

    The authors of this article contend that the Guinan and Foulds study was inadequately designed and executed, and the results indicate little of the "usefulness" of the test, much less illuminate the important hypothesis central to the investigation. Specific suggestions for further research in marathon group evaluation are made. (Author)

  9. Sleep memory processing: the sequential hypothesis

    PubMed Central

    Giuditta, Antonio

    2014-01-01

    According to the sequential hypothesis (SH) memories acquired during wakefulness are processed during sleep in two serial steps respectively occurring during slow wave sleep (SWS) and rapid eye movement (REM) sleep. During SWS memories to be retained are distinguished from irrelevant or competing traces that undergo downgrading or elimination. Processed memories are stored again during REM sleep which integrates them with preexisting memories. The hypothesis received support from a wealth of EEG, behavioral, and biochemical analyses of trained rats. Further evidence was provided by independent studies of human subjects. SH basic premises, data, and interpretations have been compared with corresponding viewpoints of the synaptic homeostatic hypothesis (SHY). Their similarities and differences are presented and discussed within the framework of sleep processing operations. SHY’s emphasis on synaptic renormalization during SWS is acknowledged to underline a key sleep effect, but this cannot marginalize sleep’s main role in selecting memories to be retained from downgrading traces, and in their integration with preexisting memories. In addition, SHY’s synaptic renormalization raises an unsolved dilemma that clashes with the accepted memory storage mechanism exclusively based on modifications of synaptic strength. This difficulty may be bypassed by the assumption that SWS-processed memories are stored again by REM sleep in brain subnuclear quantum particles. Storing of memories in quantum particles may also occur in other vigilance states. Hints are provided on ways to subject the quantum hypothesis to experimental tests. PMID:25565985

  10. A Philosophical Critique of Null Hypothesis Testing.

    ERIC Educational Resources Information Center

    Orey III, Michael A.; And Others

    1989-01-01

    An attempt is made to clarify the philosophical foundations of the debate over research methodology appropriate for psychology in particular and the utility of null hypothesis testing in general. The article also relates the debate to education and suggests that the debate is far from settled. (IAH)

  11. The Psycholinguistics of the Output Hypothesis.

    ERIC Educational Resources Information Center

    de Bot, Kees

    1996-01-01

    Elucidates the psycholinguistic mechanics of the "output hypothesis" and argues that output serves an important role in second language acquisition because it generates specific input the cognitive system needs to build up a coherent set of knowledge. The article hypothesizes that the locus of the effect of output is in the transition of…

  12. Measurement of LINAC 90 degrees head leakage radiation TVL values.

    PubMed

    Li, Zuofeng; Mutic, Sasa; Low, Daniel

    2006-09-01

    One of the key components in modern LINAC room shielding design is the amount of 90 degrees head leakage radiation levels. With the general clinical acceptance of intensity-modulated radiation therapy (IMRT) technique, accurate knowledge of this quantity has become even more important. Measurement of 90 degrees head leakage radiation of medical linear accelerators can be technically challenging due to the low dose rate causing poor signal-to-noise ratios in most detectors. 90 degrees leakage tenth-value layer (TVL) values in concrete have not been reported for the Elekta linear accelerators. This report describes our measurements of 90 degrees leakage TVL values for 6, 10, and 18 MV x-ray beams for an Elekta Precise Treatment System. A large-volume (1000 cm3) unpressurized ionization chamber and a high sensitivity electrometer, together with a separate chamber bias power supply, were used in these measurements in order to maximize the signal-to-noise ratio. A lead enclosure, of minimum thickness 10 cm, was constructed inside the treatment room to house the ion chamber to reduce the influence of room-scattered radiation. A square aperture of 10 X 10 cm2 area was left in the shield and aimed towards the accelerator head. Measurements were performed with the chamber placed at approximately 2 m from the accelerator isocenter. Concrete slabs with individual dimensions of approximately 40 X 40 cm2 cross-sectional area and 5 cm thickness were placed between the accelerator head and the ion chamber for these measurements. The measurements were performed with total concrete thickness of up to 80 cm, so that values up to the third TVL were measured. These measurements showed thatthe first concrete TVL values are 22, 23, and 28 cm (8.6, 9.1, and 10.5 in.) for 6, 10, and 18 MV beams, while the average of the first 3 TVL's were 25, 26, and 29 cm (9.9, 10.2, and 11.5 in.). Measured values agreed to within 10% of previously reported values for Varian linear accelerators for

  13. Numerical Simulations of Leakage from Underground LPG Storage Caverns

    SciTech Connect

    Yamamoto, Hajime; Pruess, Karsten

    2004-09-01

    To secure a stable supply of petroleum gas, underground storage caverns for liquified petroleum gas (LPG) are commonly used in many countries worldwide. Storing LPG in underground caverns requires that the surrounding rock mass remain saturated with groundwater and that the water pressure be higher than the liquid pressure inside the cavern. In previous studies, gas containment criteria for underground gas storage based on hydraulic gradient and pressure have been discussed, but these studies do not consider the physicochemical characteristics and behavior of LPG such as vaporization and dissolution in groundwater. Therefore, while these studies are very useful for designing storage caverns, they do not provide better understanding of the either the environmental effects of gas contamination or the behavior of vaporized LPG. In this study, we have performed three-phase fluid flow simulations of gas leakage from underground LPG storage caverns, using the multiphase multicomponent nonisothermal simulator TMVOC (Pruess and Battistelli, 2002), which is capable of solving the three-phase nonisothermal flow of water, gas, and a multicomponent mixture of volatile organic chemicals (VOCs) in multidimensional heterogeneous porous media. A two-dimensional cross-sectional model resembling an actual underground LPG facility in Japan was developed, and gas leakage phenomena were simulated for three different permeability models: (1) a homogeneous model, (2) a single-fault model, and (3) a heterogeneous model. In addition, the behavior of stored LPG was studied for the special case of a water curtain suddenly losing its function because of operational problems, or because of long-term effects such as clogging of boreholes. The results of the study indicate the following: (1) The water curtain system is a very powerful means for preventing gas leakage from underground storage facilities. By operating with appropriate pressure and layout, gas containment can be ensured. (2

  14. Experimental Evidence for Self-Limiting Reactive Flow through a Fractured Cement Core: Implications for Time-Dependent Wellbore Leakage

    SciTech Connect

    Huerta, Nicolas J; Hesse, Marc A; Bryant, Steven L; Strazisar, Brian R; Lopano, Christina L

    2013-01-01

    We present a set of reactive transport experiments in cement fractures. The experiments simulate coupling between flow and reaction when acidic, CO{sub 2}-rich fluids flow along a leaky wellbore. An analog dilute acid with a pH between 2.0 and 3.15 was injected at constant rate between 0.3 and 9.4 cm/s into a fractured cement core. Pressure differential across the core and effluent pH were measured to track flow path evolution, which was analyzed with electron microscopy after injection. In many experiments reaction was restricted within relatively narrow, tortuous channels along the fracture surface. The observations are consistent with coupling between flow and dissolution/precipitation. Injected acid reacts along the fracture surface to leach calcium from cement phases. Ahead of the reaction front, high pH pore fluid mixes with calcium-rich water and induces mineral precipitation. Increases in the pressure differential for most experiments indicate that precipitation can be sufficient to restrict flow. Experimental data from this study combined with published field evidence for mineral precipitation along cemented annuli suggests that leakage of CO{sub 2}-rich fluids along a wellbore may seal the leakage pathway if the initial aperture is small and residence time allows mobilization and precipitation of minerals along the fracture.

  15. A novel method to determine air leakage in heat pump clothes dryers

    SciTech Connect

    Bansal, Pradeep; Mohabir, Amar; Miller, William

    2016-01-06

    A heat pump clothes dryer offers the potential to save a significant amount of energy as compared with conventional vented electric dryers. Although heat pump clothes dryers (HPCD) offer higher energy efficiency; it has been observed that they are prone to air leakages, which inhibits the HPCD's gain in efficiency. This study serves to develop a novel method of quantifying leakage, and to determine specific leakage locations in the dryer drum and air circulation system. The basis of this method is the American Society of Testing and Materials (ASTM) standard E779 10, which is used to determine air leakage area in a household ventilation system through fan pressurization. This ASTM method is adapted to the dryer system, and the leakage area is determined by an analysis of the leakage volumetric flow - pressure relationship. Easily accessible leakage points were quantified: the front and back crease (in the dryer drum), the leakage in the dryer duct, the air filter, and the remaining leakage in the drum. The procedure allows investigators to determine major components contributing to leakage in HPCDs, thus improving component design features that result in more efficient HPCD systems.

  16. A novel method to determine air leakage in heat pump clothes dryers

    DOE PAGES

    Bansal, Pradeep; Mohabir, Amar; Miller, William

    2016-01-06

    A heat pump clothes dryer offers the potential to save a significant amount of energy as compared with conventional vented electric dryers. Although heat pump clothes dryers (HPCD) offer higher energy efficiency; it has been observed that they are prone to air leakages, which inhibits the HPCD's gain in efficiency. This study serves to develop a novel method of quantifying leakage, and to determine specific leakage locations in the dryer drum and air circulation system. The basis of this method is the American Society of Testing and Materials (ASTM) standard E779 10, which is used to determine air leakage areamore » in a household ventilation system through fan pressurization. This ASTM method is adapted to the dryer system, and the leakage area is determined by an analysis of the leakage volumetric flow - pressure relationship. Easily accessible leakage points were quantified: the front and back crease (in the dryer drum), the leakage in the dryer duct, the air filter, and the remaining leakage in the drum. The procedure allows investigators to determine major components contributing to leakage in HPCDs, thus improving component design features that result in more efficient HPCD systems.« less

  17. Studies of axial-leakage simulations for homogeneous and heterogeneous EBR-II core configurations

    SciTech Connect

    Grimm, K.N.; Meneghetti, D.

    1985-08-01

    When calculations of flux are done in less than three dimensions, leakage-absorption cross sections are normally used to model leakages (flows) in the dimensions for which the flux is not calculated. Since the neutron flux is axially dependent, the leakages, and hence the leakage-absorption cross sections, are also axially dependent. Therefore, to obtain axial flux profiles (or reaction rates) for individual subassemblies, an XY-geometry calculation delineating each subassembly has to be done at several axial heights with space- and energy-dependent leakage-absorption cross sections that are appropriate for each height. This report discusses homogeneous and heterogeneous XY-geometry calculations at various axial locations and using several differing assumptions for the calculation of the leakage-absorption cross section. The positive (outward) leakage-absorption cross sections are modeled as actual leakage absorptions, but the negative (inward) leakage-absorption cross sections are modeled as either negative leakage absorptions (+-B/sup 2/ method) or positive downscatter cross sections (the ..sigma../sub s/(1 ..-->.. g) method). 3 refs., 52 figs., 10 tabs.

  18. Cortical Neural Computation by Discrete Results Hypothesis.

    PubMed

    Castejon, Carlos; Nuñez, Angel

    2016-01-01

    One of the most challenging problems we face in neuroscience is to understand how the cortex performs computations. There is increasing evidence that the power of the cortical processing is produced by populations of neurons forming dynamic neuronal ensembles. Theoretical proposals and multineuronal experimental studies have revealed that ensembles of neurons can form emergent functional units. However, how these ensembles are implicated in cortical computations is still a mystery. Although cell ensembles have been associated with brain rhythms, the functional interaction remains largely unclear. It is still unknown how spatially distributed neuronal activity can be temporally integrated to contribute to cortical computations. A theoretical explanation integrating spatial and temporal aspects of cortical processing is still lacking. In this Hypothesis and Theory article, we propose a new functional theoretical framework to explain the computational roles of these ensembles in cortical processing. We suggest that complex neural computations underlying cortical processing could be temporally discrete and that sensory information would need to be quantized to be computed by the cerebral cortex. Accordingly, we propose that cortical processing is produced by the computation of discrete spatio-temporal functional units that we have called "Discrete Results" (Discrete Results Hypothesis). This hypothesis represents a novel functional mechanism by which information processing is computed in the cortex. Furthermore, we propose that precise dynamic sequences of "Discrete Results" is the mechanism used by the cortex to extract, code, memorize and transmit neural information. The novel "Discrete Results" concept has the ability to match the spatial and temporal aspects of cortical processing. We discuss the possible neural underpinnings of these functional computational units and describe the empirical evidence supporting our hypothesis. We propose that fast-spiking (FS

  19. Cortical Neural Computation by Discrete Results Hypothesis

    PubMed Central

    Castejon, Carlos; Nuñez, Angel

    2016-01-01

    One of the most challenging problems we face in neuroscience is to understand how the cortex performs computations. There is increasing evidence that the power of the cortical processing is produced by populations of neurons forming dynamic neuronal ensembles. Theoretical proposals and multineuronal experimental studies have revealed that ensembles of neurons can form emergent functional units. However, how these ensembles are implicated in cortical computations is still a mystery. Although cell ensembles have been associated with brain rhythms, the functional interaction remains largely unclear. It is still unknown how spatially distributed neuronal activity can be temporally integrated to contribute to cortical computations. A theoretical explanation integrating spatial and temporal aspects of cortical processing is still lacking. In this Hypothesis and Theory article, we propose a new functional theoretical framework to explain the computational roles of these ensembles in cortical processing. We suggest that complex neural computations underlying cortical processing could be temporally discrete and that sensory information would need to be quantized to be computed by the cerebral cortex. Accordingly, we propose that cortical processing is produced by the computation of discrete spatio-temporal functional units that we have called “Discrete Results” (Discrete Results Hypothesis). This hypothesis represents a novel functional mechanism by which information processing is computed in the cortex. Furthermore, we propose that precise dynamic sequences of “Discrete Results” is the mechanism used by the cortex to extract, code, memorize and transmit neural information. The novel “Discrete Results” concept has the ability to match the spatial and temporal aspects of cortical processing. We discuss the possible neural underpinnings of these functional computational units and describe the empirical evidence supporting our hypothesis. We propose that fast

  20. Einstein's Revolutionary Light-Quantum Hypothesis

    NASA Astrophysics Data System (ADS)

    Stuewer, Roger H.

    2005-05-01

    The paper in which Albert Einstein proposed his light-quantum hypothesis was the only one of his great papers of 1905 that he himself termed ``revolutionary.'' Contrary to widespread belief, Einstein did not propose his light-quantum hypothesis ``to explain the photoelectric effect.'' Instead, he based his argument for light quanta on the statistical interpretation of the second law of thermodynamics, with the photoelectric effect being only one of three phenomena that he offered as possible experimental support for it. I will discuss Einstein's light-quantum hypothesis of 1905 and his introduction of the wave-particle duality in 1909 and then turn to the reception of his work on light quanta by his contemporaries. We will examine the reasons that prominent physicists advanced to reject Einstein's light-quantum hypothesis in succeeding years. Those physicists included Robert A. Millikan, even though he provided convincing experimental proof of the validity of Einstein's equation of the photoelectric effect in 1915. The turning point came after Arthur Holly Compton discovered the Compton effect in late 1922, but even then Compton's discovery was contested both on experimental and on theoretical grounds. Niels Bohr, in particular, had never accepted the reality of light quanta and now, in 1924, proposed a theory, the Bohr-Kramers-Slater theory, which assumed that energy and momentum were conserved only statistically in microscopic interactions. Only after that theory was disproved experimentally in 1925 was Einstein's revolutionary light-quantum hypothesis generally accepted by physicists---a full two decades after Einstein had proposed it.

  1. Study of the Standard k-ɛ Model for Tip Leakage Flow in an Axial Compressor Rotor

    NASA Astrophysics Data System (ADS)

    Gao, Yanfei; Liu, Yangwei; Zhong, Luyang; Hou, Jiexuan; Lu, Lipeng

    2016-12-01

    The standard k-ɛ model (SKE) and the Reynolds stress model (RSM) are employed to predict the tip leakage flow (TLF) in a low-speed large-scale axial compressor rotor. Then, a new research method is adopted to "freeze" the turbulent kinetic energy and dissipation rate of the flow field derived from the RSM, and obtain the turbulent viscosity using the Boussinesq hypothesis. The Reynolds stresses and mean flow field computed on the basis of the frozen viscosity are compared with the results of the SKE and the RSM. The flow field in the tip region based on the frozen viscosity is more similar to the results of the RSM than those of the SKE, although certain differences can be observed. This finding indicates that the non-equilibrium turbulence transport nature plays an important role in predicting the TLF, as well as the turbulence anisotropy.

  2. Experiences in the management of anastomotic leakages and analysis of the factors affecting leakage healing in patients with esophagogastric junction cancer

    PubMed Central

    Ding, Ningning; He, Jie; Gao, Shugeng; Zhao, Yue; Yang, Ding; Sun, Kelin; Cheng, Guiyu; Mu, Juwei; Xue, Qi; Wang, Dali; Zhao, Jun; Gao, Yushun; Liu, Xiangyang; Fang, Dekang; Li, Jian; Wang, Yonggang; Huang, Jinfeng; Wang, Bing; Zhang, Liangze

    2017-01-01

    Background It was reported in the literatures that the incidence of anastomotic leakage in patients with esophagogastric junction cancer decreased due to application of staplers and closure devices as well as gastric conduit technique in recent years, however, it increased slightly at our center since widely using the above devices and gastric conduit techniques from 2009. The objective of this study was to summarize our experiences in the management of anastomotic leakages and analyze the factors affecting leakage healing in the patients with esophagogastric junction cancer after surgical resection in recent 6 years. Methods All patients who received surgical resections for esophagogastric junction cancer and diagnosed anastomotic leak at our center between January 2009 and December 2014 were retrospectively analyzed, we also enrolled the patients who had a longer hospital stay (>30 days) as they may develop anastomotic leak. The binary logistic regression in SPSS 16.0 was applied to analyze the factors that may affect leakage healing. Results Of the 1,815 surgically treated esophagogastric junction cancer patients, 91 cases were diagnosed anastomotic leakage postoperatively. The patients were divided into two groups based on the median leakage healing time (40 days) in this series: fast healing group (37 cases) and slowly healing group (54 cases). All factors that may affect the leakage healing were put into analysis by using binary logistic regression. The results of the analysis showed that leakage size (OR =1.073, P=0.004), thoracic drainage (OR =12.937, P=0.037) and smoking index ≤400 (OR =1.001, P=0.04) significantly affected the healing time, while drinking history (P=0.177), duration of fever after anastomotic leak developed (P=0.084), and hypoproteinemia after leak (P=0.169) also apparently but not significantly affect the healing time. Conclusions Though many factors may affect leakage healing in the esophagogastric junction carcinoma patients, leakage

  3. An Advanced Leakage Scheme for Neutrino Treatment in Astrophysical Simulations

    NASA Astrophysics Data System (ADS)

    Perego, A.; Cabezón, R. M.; Käppeli, R.

    2016-04-01

    We present an Advanced Spectral Leakage (ASL) scheme to model neutrinos in the context of core-collapse supernovae (CCSNe) and compact binary mergers. Based on previous gray leakage schemes, the ASL scheme computes the neutrino cooling rates by interpolating local production and diffusion rates (relevant in optically thin and thick regimes, respectively) separately for discretized values of the neutrino energy. Neutrino trapped components are also modeled, based on equilibrium and timescale arguments. The better accuracy achieved by the spectral treatment allows a more reliable computation of neutrino heating rates in optically thin conditions. The scheme has been calibrated and tested against Boltzmann transport in the context of Newtonian spherically symmetric models of CCSNe. ASL shows a very good qualitative and a partial quantitative agreement for key quantities from collapse to a few hundreds of milliseconds after core bounce. We have proved the adaptability and flexibility of our ASL scheme, coupling it to an axisymmetric Eulerian and to a three-dimensional smoothed particle hydrodynamics code to simulate core collapse. Therefore, the neutrino treatment presented here is ideal for large parameter-space explorations, parametric studies, high-resolution tests, code developments, and long-term modeling of asymmetric configurations, where more detailed neutrino treatments are not available or are currently computationally too expensive.

  4. Capillary leakage syndrome: a case report and a review.

    PubMed

    Garcês, S; Araújo, F; Rego, F; Soares, J L Ducla; Carlos, A G Palma

    2002-12-01

    Capillary leakage Syndrome (CLS) is a rare clinical syndrome, that was first described in 1960, characterized by acute episodes of generalized edema, hemoconcentration, hypoproteinemia and monoclonal gammopathy, in the vast majority of cases. We describe a 39-year-old man with anasarca, bilateral pleural and pericardial effusions, ascites and diffuse alveolo-intersticial edema. Clinical and laboratory findings were consistent with an acute episode of CLS. Treatment with prednisone, furosemide and aminophylline was started, which lead to a gradual improvement in 48 hours. Pathophysiologically there is an increase in capillary permeability with the extravasation of fluid and plasmatic proteins to the extravascular space that can lead to hypovolaemic shock. In the second phase there is a reentry of the fluid overload leading to pulmonary edema. The etiology of this hyperpermeability still remains unclear. The role of cytokines has become central in the comprehension of pathophysiology of CLS. Adhesion molecules are probably also involved in the genesis of capillary leakage. CLS treatment remains empirical. However, at present it seems that the association of steroids with furosemide, aminophylline and terbutaline are capable of controlling the clinical manifestation of the acute episodes in most cases. To our knowledge no prophylatic therapy has clearly proven its efficacy. There are only a few series analyzing the long-term evolution of patients with CLS. Further studies are necessary with the objective to collect enough patients with CLS to observe natural history of the disease and evaluate the efficacy of empiric treatments.

  5. Investigation of the Operating Properties of the Leakage Current Anemometer

    NASA Technical Reports Server (NTRS)

    Fucks, Wilhelm

    1947-01-01

    Freedom from inertia, erosion of electrodes, and reaction make the leakage current particularly appropriate for the measurement of flow velocities in gases. Apparatus previously described has now been improved by reducing the size of the electrodes by one -thousandth, as is necessary aerodynamically, and by increasing the magnitude of the current from 1000 to 10,000 times; the latter result was obtained.by use of mercury high-pressure lamps set up at the one focal point of an ellipsoidal reflector with the cathodes arranged at the other focal point or by use of suitable X-ray radiation. Families of calibration curves were taken with a number of vivid tests conditions of the greatest variety and the operating properties of the instrument were widely elucidated by calculation of the sensitivity to fluctuation; this was done at first for operation at stationary conditions only; due to the freedom from inertia the instationary conditions were thus also given. Accordingly, the leakage current anemometer ought to be appropriate for investigations of turbulence,

  6. AN ADVANCED LEAKAGE SCHEME FOR NEUTRINO TREATMENT IN ASTROPHYSICAL SIMULATIONS

    SciTech Connect

    Perego, A.; Cabezón, R. M.; Käppeli, R.

    2016-04-15

    We present an Advanced Spectral Leakage (ASL) scheme to model neutrinos in the context of core-collapse supernovae (CCSNe) and compact binary mergers. Based on previous gray leakage schemes, the ASL scheme computes the neutrino cooling rates by interpolating local production and diffusion rates (relevant in optically thin and thick regimes, respectively) separately for discretized values of the neutrino energy. Neutrino trapped components are also modeled, based on equilibrium and timescale arguments. The better accuracy achieved by the spectral treatment allows a more reliable computation of neutrino heating rates in optically thin conditions. The scheme has been calibrated and tested against Boltzmann transport in the context of Newtonian spherically symmetric models of CCSNe. ASL shows a very good qualitative and a partial quantitative agreement for key quantities from collapse to a few hundreds of milliseconds after core bounce. We have proved the adaptability and flexibility of our ASL scheme, coupling it to an axisymmetric Eulerian and to a three-dimensional smoothed particle hydrodynamics code to simulate core collapse. Therefore, the neutrino treatment presented here is ideal for large parameter-space explorations, parametric studies, high-resolution tests, code developments, and long-term modeling of asymmetric configurations, where more detailed neutrino treatments are not available or are currently computationally too expensive.

  7. Greater focus needed on methane leakage from natural gas infrastructure

    PubMed Central

    Alvarez, Ramón A.; Pacala, Stephen W.; Winebrake, James J.; Chameides, William L.; Hamburg, Steven P.

    2012-01-01

    Natural gas is seen by many as the future of American energy: a fuel that can provide energy independence and reduce greenhouse gas emissions in the process. However, there has also been confusion about the climate implications of increased use of natural gas for electric power and transportation. We propose and illustrate the use of technology warming potentials as a robust and transparent way to compare the cumulative radiative forcing created by alternative technologies fueled by natural gas and oil or coal by using the best available estimates of greenhouse gas emissions from each fuel cycle (i.e., production, transportation and use). We find that a shift to compressed natural gas vehicles from gasoline or diesel vehicles leads to greater radiative forcing of the climate for 80 or 280 yr, respectively, before beginning to produce benefits. Compressed natural gas vehicles could produce climate benefits on all time frames if the well-to-wheels CH4 leakage were capped at a level 45–70% below current estimates. By contrast, using natural gas instead of coal for electric power plants can reduce radiative forcing immediately, and reducing CH4 losses from the production and transportation of natural gas would produce even greater benefits. There is a need for the natural gas industry and science community to help obtain better emissions data and for increased efforts to reduce methane leakage in order to minimize the climate footprint of natural gas. PMID:22493226

  8. Greater focus needed on methane leakage from natural gas infrastructure.

    PubMed

    Alvarez, Ramón A; Pacala, Stephen W; Winebrake, James J; Chameides, William L; Hamburg, Steven P

    2012-04-24

    Natural gas is seen by many as the future of American energy: a fuel that can provide energy independence and reduce greenhouse gas emissions in the process. However, there has also been confusion about the climate implications of increased use of natural gas for electric power and transportation. We propose and illustrate the use of technology warming potentials as a robust and transparent way to compare the cumulative radiative forcing created by alternative technologies fueled by natural gas and oil or coal by using the best available estimates of greenhouse gas emissions from each fuel cycle (i.e., production, transportation and use). We find that a shift to compressed natural gas vehicles from gasoline or diesel vehicles leads to greater radiative forcing of the climate for 80 or 280 yr, respectively, before beginning to produce benefits. Compressed natural gas vehicles could produce climate benefits on all time frames if the well-to-wheels CH(4) leakage were capped at a level 45-70% below current estimates. By contrast, using natural gas instead of coal for electric power plants can reduce radiative forcing immediately, and reducing CH(4) losses from the production and transportation of natural gas would produce even greater benefits. There is a need for the natural gas industry and science community to help obtain better emissions data and for increased efforts to reduce methane leakage in order to minimize the climate footprint of natural gas.

  9. Leakage predictions for Rayleigh-step, helium-purge seals

    NASA Technical Reports Server (NTRS)

    Proctor, Margaret P.

    1988-01-01

    Rayleigh-step, helium purge, annular shaft seals, studied for use in liquid oxygen turbopumps, generate a hydrodynamic force that enables the seal to follow shaft perturbations. Hence, smaller clearances can be used to reduce seal leakage. FLOWCAL, a computer code developed by Mechanical Technology Incorporated, predicts gas flow rate through an annular seal with an axial pressure gradient. Analysis of a 50-mm Rayleigh-step, helium-purge, annular seal showed the flow rate increased axial pressure gradient, downstream pressure, and eccentricity ratio. Increased inlet temperature reduced leakage. Predictions made at maximum and minimum clearances (due to centrifugal and thermal growths, machining tolerances and + or - 2 percent uncertainty in the clearance measurement) placed wide boundaries on expected flow rates. The widest boundaries were set by thermal growth conditions. Predicted flow rates for a 50-mm Rayleigh-step, helium-purge, annular seal underestimated measured flow rates by three to seven times. However, the analysis did accurately predict flow rates for choked gas flow through annular seals when compared to flow rates measured in two other independent studies.

  10. Low standby leakage 12T SRAM cell characterisation

    NASA Astrophysics Data System (ADS)

    Yadav, Arjun; Nakhate, Sangeeta

    2016-09-01

    In this work, a low power and variability-aware static random access memory (SRAM) architecture based on a twelve-transistor (12T) cell is proposed. This cell obtains low static power dissipation due to a parallel global latch (G-latch) and storage latch (S-latch), along with a global wordline (GWL), which offer a high cell ratio and pull-up ratio for reliable read and write operations and a low cell ratio and pull-up ratio during idle mode to reduce the standby power dissipation. In the idle state, only the S-latch stores bits, while the G-latch is isolated from the S-latch and the GWL is deactivated. The leakage power consumption of the proposed SRAM cell is thereby reduced by 38.7% compared to that of the conventional six-transistor (6T) SRAM cell. This paper evaluates the impact of the chip supply voltage and surrounding temperature variations on the standby leakage power and observes considerable improvement in the power dissipation. The read/write access delay, read static noise margin (SNM) and write SNM were evaluated, and the results were compared with those of the standard 6T SRAM cell. The proposed cell, when compared with the existing cell using the Monte Carlo method, shows an appreciable improvement in the standby power dissipation and layout area.

  11. Variable cycle stirling engine and gas leakage control system therefor

    SciTech Connect

    Otters, J.

    1984-12-25

    An improved thermal engine of the type having a displacer body movable between the hot end and the cold end of a chamber for subjecting a fluid within that chamber to a thermodynamic cycle and having a work piston driven by the fluid for deriving a useful work output. The work piston pumps a hydraulic fluid and a hydraulic control valve is connected in line with the hydraulic output conduit such that the flow of hydraulic fluid may be restricted to any desired degree or stopped altogether. The work piston can therefore be controlled by means of a controller device independently from the movement of the displacer such that a variety of engine cycles can be obtained for optimum engine efficiency under varying load conditions. While a Stirling engine cycle is particularly contemplated, other engine cycles may be obtained by controlling the movement of the displacer and work pistons. Also disclosed are a working gas recovery system for controlling leakage of working gas from the displacer chamber, and a compound work piston arrangement for preventing leakage of hydraulic fluid around the work piston into the displacer chamber.

  12. The SSME seal test program: Leakage tests for helically-grooved seals

    NASA Technical Reports Server (NTRS)

    Childs, D. W.

    1983-01-01

    Helically grooved annular seal configurations were tested in highly turbulent flow to determine if reduced leakage and enhanced stability would result from the pumping action of the seal. It was found that: (1) leakage of a helically grooved seals decreases with running speed; (2) leakage reduction due to increased running speed is greater at lower values of R sub a; (3) an asymptote for leakage reduction is indicated with increasing running speed; (4) leakage is reduced by reducing the ridge (minimum) and average clearances; (5) leakage increases with increasing pitch angles and with increasing groove depth. Plain seals with smooth rotors and stators will leak more than a helically grooved seal. It was also found that plain seals with a rough rotor and a rough stator leak less than a properly designed helically grooved seal. A properly designed helically grooved seal consumes at least twice as much power as a conventional annular seal.

  13. Accurate Evaluation of Microwave-Leakage-Induced Frequency Shifts in Fountain Clocks

    NASA Astrophysics Data System (ADS)

    Fang, Fang; Liu, Kun; Chen, Wei-Liang; Liu, Nian-Feng; Suo, Rui; Li, Tian-Chun

    2014-10-01

    We report theoretical calculations of the transition probability errors introduced by microwave leakage in Cs fountain clocks, which will shift the clock frequency. The results show that the transition probability errors are affected by the Ramsey pulse amplitude, the relative phase between the Ramsey field and the leakage field, and the asymmetry of the leakage fields for the upward and downward passages. This effect is quite different for the leakage fields presenting below the Ramsey cavity and above the Ramsey cavity. The leakage-field-induced frequency shifts of the NIM5 fountain clock in different cases are measured. The results are consistent with the theoretical calculations, and give an accurate evaluation of the leakage-field-induced frequency shifts, as distinguished from other microwave-power-related effects for the first time.

  14. Geochemical confirmation of the lunar magmasphere hypothesis

    NASA Technical Reports Server (NTRS)

    Warren, P. H.

    1985-01-01

    The lunar magmasphere (or magma ocean) hypothesis was originally conceived to account for the enrichment of cumulus plagioclase (Al and Ca) in the main (highlands) portion of the crust. The great age of the highlands, and the complementary pattern of Eu anomalies between the highlands and the younger mare basalts, helped convince most specialists that the magmasphere hypothesis is correct. Doubts persist, however, particularly among physicists concerned about heat sources. It was shown in 1976 that a plot of Na/Ca vs. Mg/Fe for pristine highlands cumulates manifests a profound bimodality: One group, the Mg-rich rocks, plots along a normal igneous trend of inverse correlation between Na/Ca and Mg/Fe; the other group, the ferroan anorthosites (FAN), features low Na/Ca and low Mg/Fe. Only the FAN group can be plausibly linked to plag. flotation over the magmasphere.

  15. Exploring heterogeneous market hypothesis using realized volatility

    NASA Astrophysics Data System (ADS)

    Chin, Wen Cheong; Isa, Zaidi; Mohd Nor, Abu Hassan Shaari

    2013-04-01

    This study investigates the heterogeneous market hypothesis using high frequency data. The cascaded heterogeneous trading activities with different time durations are modelled by the heterogeneous autoregressive framework. The empirical study indicated the presence of long memory behaviour and predictability elements in the financial time series which supported heterogeneous market hypothesis. Besides the common sum-of-square intraday realized volatility, we also advocated two power variation realized volatilities in forecast evaluation and risk measurement in order to overcome the possible abrupt jumps during the credit crisis. Finally, the empirical results are used in determining the market risk using the value-at-risk approach. The findings of this study have implications for informationally market efficiency analysis, portfolio strategies and risk managements.

  16. The Neural Rejuvenation Hypothesis of Cocaine Addiction

    PubMed Central

    Dong, Yan; Nestler, Eric J.

    2014-01-01

    A leading hypothesis guiding current molecular and cellular research of drug addiction conceptualizes key aspects of addiction as a form of memory, in which common neuroplasticity mechanisms that mediate normal learning and memory processes are “hijacked” by exposure to drugs of abuse to produce pathologic addiction-related memories. Such addiction-related memories are particularly robust and long-lasting and once formed, less amenable to updating. Here, we propose the Neural Rejuvenation Hypothesis of Cocaine Addiction: that repeated exposure to drugs of abuse induces some plasticity mechanisms that are normally associated with brain development within the brain’s reward circuitry, which mediate the highly efficient and unusually stable memory abnormalities that characterize addiction. PMID:24958329

  17. A coulombic hypothesis of mitochondrial oxidative phosphorylation.

    PubMed

    Malpress, F H

    1984-08-21

    A coulombic hypothesis of mitochondrial oxidative phosphorylation is presented, founded upon the evidence for negative fixed charge formation during electron transport chain activity. The intermediary force is electrostatic (psi H) and not electrochemical (delta mu H). The electrochemical potential of the chemiosmotic hypothesis is identified as a "phantom" parameter which owes its delusive existence to the procedures by which it is measured. The connection between psi H and the conditional delta mu H values is examined; it entails the use of a variable conversion factor, f, where delta mu H (mV) = f psi H, and the concept of the "protonic status" of the diffuse double layer. A number of problems which beset the chemiosmotic view are reappraised in the light of the new interpretation, and find authentic solutions.

  18. A hypothesis for delayed dynamic earthquake triggering

    USGS Publications Warehouse

    Parsons, T.

    2005-01-01

    It's uncertain whether more near-field earthquakes are triggered by static or dynamic stress changes. This ratio matters because static earthquake interactions are increasingly incorporated into probabilistic forecasts. Recent studies were unable to demonstrate all predictions from the static-stress-change hypothesis, particularly seismicity rate reductions. However, current dynamic stress change hypotheses do not explain delayed earthquake triggering and Omori's law. Here I show numerically that if seismic waves can alter some frictional contacts in neighboring fault zones, then dynamic triggering might cause delayed triggering and an Omori-law response. The hypothesis depends on faults following a rate/state friction law, and on seismic waves changing the mean critical slip distance (Dc) at nucleation zones.

  19. Tests of the Giant Impact Hypothesis

    NASA Technical Reports Server (NTRS)

    Jones, J. H.

    1998-01-01

    The giant impact hypothesis has gained popularity as a means of explaining a volatile-depleted Moon that still has a chemical affinity to the Earth. As Taylor's Axiom decrees, the best models of lunar origin are testable, but this is difficult with the giant impact model. The energy associated with the impact would be sufficient to totally melt and partially vaporize the Earth. And this means that there should he no geological vestige of Barber times. Accordingly, it is important to devise tests that may be used to evaluate the giant impact hypothesis. Three such tests are discussed here. None of these is supportive of the giant impact model, but neither do they disprove it.

  20. Cell repair: Revisiting the patch hypothesis

    PubMed Central

    Davenport, Nicholas R.

    2016-01-01

    ABSTRACT Plasma membrane damage elicits a complex and dynamic cellular response. A vital component of this response, membrane resealing, is thought to arise from fusion of intracellular membranous compartments to form a temporary, impermeant patch at the site of damage; however, this hypothesis has been difficult to confirm visually. By utilizing advanced microscopy technologies with high spatiotemporal resolution in wounded Xenopus laevis oocytes, we provide the first direct visualization of the membrane fusion events predicted by the patch hypothesis; we show the barrier formed by patching is capable of abating exchange of material across the plasma membrane within seconds. Profound changes also occur to the plasma membrane surrounding wounds; lipid remodeling is accompanied by membrane fusion events, both conventional (e.g., exocytosis) and novel (e.g., “explodosis”). Further, we reveal additional complexity in wound-induced subcellular patterning, supporting existing evidence that extensive interactions between lipid, protein, and ionic signaling pathways shape the cellular wound response. PMID:28042380

  1. Probability, clinical decision making and hypothesis testing

    PubMed Central

    Banerjee, A.; Jadhav, S. L.; Bhawalkar, J. S.

    2009-01-01

    Few clinicians grasp the true concept of probability expressed in the ‘P value.’ For most, a statistically significant P value is the end of the search for truth. In fact, the opposite is the case. The present paper attempts to put the P value in proper perspective by explaining different types of probabilities, their role in clinical decision making, medical research and hypothesis testing. PMID:21234167

  2. Kelvin on an old, celebrated hypothesis

    NASA Astrophysics Data System (ADS)

    Harrison, Edward

    1986-07-01

    Lord Kelvin in 1901 tested an ``old and celebrated hypothesis'' that if we could see far enough into space the whole sky would be occupied with stellar disks all of perhaps the same brightness as the Sun. Kelvin was the first to solve quantitatively and correctly the riddle of a dark night sky, a riddle that had been previously solved qualitatively by Edgar Allan Poe, and is now known as Olbers' paradox.

  3. The OPERA hypothesis: assumptions and clarifications.

    PubMed

    Patel, Aniruddh D

    2012-04-01

    Recent research suggests that musical training enhances the neural encoding of speech. Why would musical training have this effect? The OPERA hypothesis proposes an answer on the basis of the idea that musical training demands greater precision in certain aspects of auditory processing than does ordinary speech perception. This paper presents two assumptions underlying this idea, as well as two clarifications, and suggests directions for future research.

  4. Testing the single-state dominance hypothesis

    SciTech Connect

    Álvarez-Rodríguez, R.; Moreno, O.; Moya de Guerra, E.; Sarriguren, P.; Šimkovic, F.; Faessler, A.

    2013-12-30

    We present a theoretical analysis of the single-state dominance hypothesis for the two-neutrino double-beta decay process. The theoretical framework is a proton-neutron QRPA based on a deformed Hartree-Fock mean field with BCS pairing correlations. We focus on the decays of {sup 100}Mo, {sup 116}Cd and {sup 128}Te. We do not find clear evidences for single-state dominance within the present approach.

  5. An impact hypothesis for Venus argon anomalies

    NASA Astrophysics Data System (ADS)

    Kaula, W. M.; Newman, W. I.

    1997-03-01

    The Ar-36+38 argon-excess anomally of Venus has been hypothesized to have its origin in the impact of an outer solar system body of about 100-km diameter. A critical evaluation is made of this hypothesis and its competitors; it is judged that its status must for the time being remain one of 'Sherlock Holmes' type, in that something so improbable must be accepted when all alternatives are eliminated.

  6. Large numbers hypothesis. I - Classical formalism

    NASA Technical Reports Server (NTRS)

    Adams, P. J.

    1982-01-01

    A self-consistent formulation of physics at the classical level embodying Dirac's large numbers hypothesis (LNH) is developed based on units covariance. A scalar 'field' phi(x) is introduced and some fundamental results are derived from the resultant equations. Some unusual properties of phi are noted such as the fact that phi cannot be the correspondence limit of a normal quantum scalar field.

  7. Sea otter health: Challenging a pet hypothesis

    PubMed Central

    Lafferty, Kevin D.

    2015-01-01

    A recent series of studies on tagged sea otters (Enhydra lutris nereis) challenges the hypothesis that sea otters are sentinels of a dirty ocean, in particular, that pet cats are the main source of exposure to Toxoplasma gondii in central California. Counter to expectations, sea otters from unpopulated stretches of coastline are less healthy and more exposed to parasites than city-associated otters. Ironically, now it seems that spillover from wildlife, not pets, dominates spatial patterns of disease transmission. PMID:26155464

  8. Threshold hypothesis revisited in the global perspective.

    PubMed

    Lin, W L

    1984-03-01

    International cross-sectional data for 1975 were used to examine the relationship between fertility and socioeconomic development in 116 developing countries. The choice of countries was based primarily on the availability of data on some major development indicators. These 116 countries account for about 98% of world population, with the exclusion of mainland China. The study included 34 economically more developed countries and 82 economically less developed countries. Countries more developed included 27 developed market countries, 6 centrally planned economies of Eastern Europe, and the USSR. The less developed countries included in this study have market economies with the exception of Viet Nam, which has a centrally planned economy. The 18 development indicators were classified into 3 categories: 8 demographic indicators; 8 social indicators; and 2 economic indicators. This study tests 1 aspect of the relationship between fertility decline and socioeconomic development, i.e., the threshold hypothesis. The central point of this hypothesis is that fertility levels resist forces tending towards a decline until a certain level of development is achieved. Beyond this point, fertility eventually will fall to a relatively low level. The evidence suggests that changes in levels of development variables may have little impact on the level of fertility in countries of the high fertility group, but fertility levels are related to development variables in the medium and low fertility group. The results conform with the threshold hypothesis. The regression results generally are consistent with the conclusion of past studies and support the recommendation that development policy should consider the effects of development variables such as education and health on fertility change rather than continuing to treat the fertility change as an exogenous variable in the development process. The study results are consistent with the hypothesis that specific socioeconomic

  9. An update on the amyloid hypothesis.

    PubMed

    Eckman, Christopher B; Eckman, Elizabeth A

    2007-08-01

    Alzheimer's disease (AD) is a devastating neurodegenerative disease. To rationally develop novel therapeutic and/or preventative agents for AD, an understanding of the etiology and pathogenesis of this complex disease is necessary. This article examines the evidence for the amyloid hypothesis of AD pathogenesis and discusses how it relates to the neurological and neuropathological features of AD, the known genetic risk factors and causative mutations, and the heightened risk associated with advanced age.

  10. Towards a glutamate hypothesis of depression

    PubMed Central

    Sanacora, Gerard; Treccani, Giulia; Popoli, Maurizio

    2011-01-01

    Half a century after the first formulation of the monoamine hypothesis, compelling evidence implies that long-term changes in an array of brain areas and circuits mediating complex cognitive-emotional behaviors represent the biological underpinnings of mood/anxiety disorders. A large number of clinical studies suggest that pathophysiology is associated with dysfunction of the predominant glutamatergic system, malfunction in the mechanisms regulating clearance and metabolism of glutamate, and cytoarchitectural/morphological maladaptive changes in a number of brain areas mediating cognitive-emotional behaviors. Concurrently, a wealth of data from animal models have shown that different types of environmental stress enhance glutamate release/transmission in limbic/cortical areas and exert powerful structural effects, inducing dendritic remodeling, reduction of synapses and possibly volumetric reductions resembling those observed in depressed patients. Because a vast majority of neurons and synapses in these areas and circuits use glutamate as neurotransmitter, it would be limiting to maintain that glutamate is in some way ‘involved’ in mood/anxiety disorders; rather it should be recognized that the glutamatergic system is a primary mediator of psychiatric pathology and, potentially, also a final common pathway for the therapeutic action of antidepressant agents. A paradigm shift from a monoamine hypothesis of depression to a neuroplasticity hypothesis focused on glutamate may represent a substantial advancement in the working hypothesis that drives research for new drugs and therapies. Importantly, despite the availability of multiple classes of drugs with monoamine-based mechanisms of action, there remains a large percentage of patients who fail to achieve a sustained remission of depressive symptoms. The unmet need for improved pharmacotherapies for treatment-resistant depression means there is a large space for the development of new compounds with novel

  11. Sea otter health: challenging a pet hypothesis

    USGS Publications Warehouse

    Lafferty, Kevin D.

    2015-01-01

    A recent series of studies on tagged sea otters (Enhydra lutris nereis) challenges the hypothesis that sea otters are sentinels of a dirty ocean, in particular, that pet cats are the main source of exposure to Toxoplasma gondii in central California. Counter to expectations, sea otters from unpopulated stretches of coastline are less healthy and more exposed to parasites than city-associated otters. Ironically, now it seems that spillover from wildlife, not pets, dominates spatial patterns of disease transmission.

  12. The study on leakage reappearance test of high pressure hose for power steering system

    NASA Astrophysics Data System (ADS)

    Lee, Gi-Chun; Kim, Hyoung-Eui; Park, Jong-Won; Jeong, Won-Wook; Lee, Jong-Hwang; Lim, Young-Han; Hwang, Kwon-Tae; Lee, Young-Shin; Kim, Jae-Hoon

    2009-07-01

    Generally, a leakage in a high pressure hose assembly can be determined if hydraulic fluid falls down through fitting which is swaged with a rubber hose. This study tried to visualize leakage, which is considered a failure occurring often in the hydraulic system. In the case of methods which verify leakage paths in the power steering hydraulic system equipped with a high pressure hose assembly, three types of leakage paths, which could be seen by cutting the swaging part, were generally found. However, it was difficult to find out leakage paths by using power steering oil. In this study, four methods, including the thermal burn image method, the hole drilling method of fitting metal, the white paint infiltration method, and the fluorescent infiltration method, were tried to introduce. The thermal burn image method failed to find out the leakage path between the fitting part and the rubber part. The hole drilling method is the way to check a leakage path on the fitting part, which doesn't need to cut a hose assembly. This method succeeds to visualize the leakage path partially but it could not check a sequential path of leakage, either, because it needs to drill more closely. The white paint infiltration method also could find the leakage path partially by using white paint mixed with thinner, which was pressurized by hand pump, instead of power steering oil. This method could check the leakage path by cutting the swaging part. The fluorescent infiltration method could verify the leakage path with naked eyes simply by holding the cutting swaging part closely to the ray of light. Reappearance test methods in the high pressure hose assembly, which include a hole drilling, a white paint infiltration, and a fluorescent infiltration method, can be applied to find the failure mode and to approve the test before the mass production of the high pressure hose.

  13. Dye leakage and modification of fast-setting mineral trioxide aggregate.

    PubMed

    Challenger, Hereward; Lane, Jason; Becker, Ryan; Nassiripour, Sepehr; Torabinejad, Mahmoud

    2015-02-01

    The objective of this investigation was to determine and decrease dye leakage of fast-setting mineral trioxide aggregate (FSMTA). Specimens using differing setting times or concentrations of calcium sulfate modified FSMTA were assessed for dye penetration. Based on the results, no statistical difference was found in the dye leakage of FSMTA compared with regular mineral trioxide aggregate (MTA). The addition of 10 percent calcium sulfate resulted in a statistical reduction in dye leakage compared to both unmodified FSMTA and regular MTA.

  14. Updating the lamellar hypothesis of hippocampal organization.

    PubMed

    Sloviter, Robert S; Lømo, Terje

    2012-01-01

    Andersen et al. (1971) proposed that excitatory activity in the entorhinal cortex propagates topographically to the dentate gyrus, and on through a "trisynaptic circuit" lying within transverse hippocampal "slices" or "lamellae." In this way, a relatively simple structure might mediate complex functions in a manner analogous to the way independent piano keys can produce a nearly infinite variety of unique outputs. The lamellar hypothesis derives primary support from the "lamellar" distribution of dentate granule cell axons (the mossy fibers), which innervate dentate hilar neurons and area CA3 pyramidal cells and interneurons within the confines of a thin transverse hippocampal segment. Following the initial formulation of the lamellar hypothesis, anatomical studies revealed that unlike granule cells, hilar mossy cells, CA3 pyramidal cells, and Layer II entorhinal cells all form axonal projections that are more divergent along the longitudinal axis than the clearly "lamellar" mossy fiber pathway. The existence of pathways with "translamellar" distribution patterns has been interpreted, incorrectly in our view, as justifying outright rejection of the lamellar hypothesis (Amaral and Witter, 1989). We suggest that the functional implications of longitudinally projecting axons depend not on whether they exist, but on what they do. The observation that focal granule cell layer discharges normally inhibit, rather than excite, distant granule cells suggests that longitudinal axons in the dentate gyrus may mediate "lateral" inhibition and define lamellar function, rather than undermine it. In this review, we attempt a reconsideration of the evidence that most directly impacts the physiological concept of hippocampal lamellar organization.

  15. Hydrologoclimatic hypothesis and examples of its use

    SciTech Connect

    Mezentsev, V.S.

    1995-05-01

    According to the opinion of a number of specialists, relative stability of the global climate has been observed throughout approximately the last eight millennia. This statement is based on the virtually constant water level of the ocean during the above period. and data on isotopic content of some chemical elements in core samples from ultradeep bore holes in the ice sheets of Antarctica, Greenland, and other places. This raises the hypothesis, according to which a universal proportionality of the heat and water resources actively participating in the exchange processes in the hydrosphere and the atmosphere of the earth should be maintained if a relatively stable global climate is retained for eight thousand years. A probable approach to justify a hydrologoclimatic hypothesis using information on the world water balance and assuming relatively stable climatic conditions is discussed. This hypothesis allows us to more properly estimate the world water balance and ratio of heat and water resources taking an active part in their exchange, as well as to analyze and generalize the available data on climatic elements, and to update their magnitudes and ratios.

  16. Origin of the moon - The collision hypothesis

    NASA Astrophysics Data System (ADS)

    Stevenson, D. J.

    By the impact or collision hypothesis, the author means any theory that seeks to derive the Moon-forming material from the outcome of one or more collisions between the Earth and other Sun-orbiting bodies. The impacting body or bodies must be large - larger than the Moon and perhaps even larger than Mars. This definition does not assume that the formation of the Moon was necessarily a singular event. Among proponents of the collision hypothesis, there are those who think that a single event overwhelmingly dominated and those who think that a few (or even many) impact events were needed. There are even versions of the collision hypothesis that are not very different from extreme versions of one of the alternative origin scenarios of capture, fission, and binary accretion! This review proceeds by advancing 10 propositions that the author believes embody the most important issues confronting the theory. These propositions may or may not be true, but they form a framework for asking the right questions.

  17. Paleoindian demography and the extraterrestrial impact hypothesis.

    PubMed

    Buchanan, Briggs; Collard, Mark; Edinborough, Kevan

    2008-08-19

    Recently it has been suggested that one or more large extraterrestrial (ET) objects struck northern North America 12,900 +/- 100 calendar years before present (calBP) [Firestone RB, et al. (2007) Proc Natl Acad Sci USA 104: 16016-16021]. This impact is claimed to have triggered the Younger Dryas major cooling event and resulted in the extinction of the North American megafauna. The impact is also claimed to have caused major cultural changes and population decline among the Paleoindians. Here, we report a study in which approximately 1,500 radiocarbon dates from archaeological sites in Canada and the United States were used to test the hypothesis that the ET resulted in population decline among the Paleoindians. Following recent studies [e.g., Gamble C, Davies W, Pettitt P, Hazelwood L, Richards M (2005) Camb Archaeol J 15:193-223), the summed probability distribution of the calibrated dates was used to identify probable changes in human population size between 15,000 and 9,000 calBP. Subsequently, potential biases were evaluated by modeling and spatial analysis of the dated occupations. The results of the analyses were not consistent with the predictions of extraterrestrial impact hypothesis. No evidence of a population decline among the Paleoindians at 12,900 +/- 100 calBP was found. Thus, minimally, the study suggests the extraterrestrial impact hypothesis should be amended.

  18. Isotopic niches support the resource breadth hypothesis.

    PubMed

    Rader, Jonathan A; Newsome, Seth D; Sabat, Pablo; Chesser, R Terry; Dillon, Michael E; Martínez Del Rio, Carlos

    2017-03-01

    Because a broad spectrum of resource use allows species to persist in a wide range of habitat types, and thus permits them to occupy large geographical areas, and because broadly distributed species have access to more diverse resource bases, the resource breadth hypothesis posits that the diversity of resources used by organisms should be positively related with the extent of their geographic ranges. We investigated isotopic niche width in a small radiation of South American birds in the genus Cinclodes. We analysed feathers of 12 species of Cinclodes to test the isotopic version of the resource breadth hypothesis and to examine the correlation between isotopic niche breadth and morphology. We found a positive correlation between the widths of hydrogen and oxygen isotopic niches (which estimate breadth of elevational range) and widths of the carbon and nitrogen isotopic niches (which estimates the diversity of resources consumed, and hence of habitats used). We also found a positive correlation between broad isotopic niches and wing morphology. Our study not only supports the resource breadth hypothesis but it also highlights the usefulness of stable isotope analyses as tools in the exploration of ecological niches. It is an example of a macroecological application of stable isotopes. It also illustrates the importance of scientific collections in ecological studies.

  19. Gravity and the quantum vacuum inertia hypothesis

    NASA Astrophysics Data System (ADS)

    Rueda, A.; Haisch, B.

    2005-08-01

    In previous work it has been shown that the electromagnetic quantum vacuum, or electromagnetic zero-point field, makes a contribution to the inertial reaction force on an accelerated object. We show that the result for inertial mass can be extended to passive gravitational mass. As a consequence the weak equivalence principle, which equates inertial to passive gravitational mass, appears to be explainable. This in turn leads to a straightforward derivation of the classical Newtonian gravitational force. We call the inertia and gravitation connection with the vacuum fields the quantum vacuum inertia hypothesis. To date only the electromagnetic field has been considered. It remains to extend the hypothesis to the effects of the vacuum fields of the other interactions. We propose an idealized experiment involving a cavity resonator which, in principle, would test the hypothesis for the simple case in which only electromagnetic interactions are involved. This test also suggests a basis for the free parameter () which we have previously defined to parametrize the interaction between charge and the electromagnetic zero-point field contributing to the inertial mass of a particle or object.

  20. Incompatibility of silver nanoparticles with lactate dehydrogenase leakage assay for cellular viability test is attributed to protein binding and reactive oxygen species generation.

    PubMed

    Oh, Seok-Jeong; Kim, Hwa; Liu, Yingqiu; Han, Hyo-Kyung; Kwon, Kyenghee; Chang, Kyung-Hwa; Park, Kwangsik; Kim, Younghun; Shim, Kyuhwan; An, Seong Soo A; Lee, Moo-Yeol

    2014-03-21

    A growing number of studies report that conventional cytotoxicity assays are incompatible with certain nanoparticles (NPs) due to artifacts caused by the distinctive characteristics of NPs. Lactate dehydrogenase (LDH) leakage assays have inadequately detected cytotoxicity of silver nanoparticles (AgNPs), leading to research into the underlying mechanism. When ECV304 endothelial-like umbilical cells were treated with citrate-capped AgNPs (cAgNPs) or bare AgNPs (bAgNPs), the plasma membrane was disrupted, but the LDH leakage assay failed to detect cytotoxicity, indicating interference with the assay by AgNPs. Both cAgNPs and bAgNPs inactivated LDH directly when treated to cell lysate as expected. AgNPs adsorbed LDH and thus LDH, together with AgNPs, was removed from assay reactants during sample preparation, with a resultant underestimation of LDH leakage from cells. cAgNPs, but not bAgNPs, generated reactive oxygen species (ROS), which were successfully scavenged by N-acetylcysteine or ascorbic acid. LDH inhibition by cAgNPs could be restored partially by simultaneous treatment with those antioxidants, suggesting the contribution of ROS to LDH inactivation. Additionally, the composition of the protein corona surrounding AgNPs was identified employing liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis. In sum, the LDH leakage assay, a conventional cell viability test method, should be employed with caution when assessing cytotoxicity of AgNPs.

  1. Method of detecting leakage from geologic formations used to sequester CO.sub.2

    DOEpatents

    White, Curt; Wells, Arthur; Diehl, J. Rodney; Strazisar, Brian

    2010-04-27

    The invention provides methods for the measurement of carbon dioxide leakage from sequestration reservoirs. Tracer moieties are injected along with carbon dioxide into geological formations. Leakage is monitored by gas chromatographic analyses of absorbents. The invention also provides a process for the early leak detection of possible carbon dioxide leakage from sequestration reservoirs by measuring methane (CH.sub.4), ethane (C.sub.2H.sub.6), propane (C.sub.3H.sub.8), and/or radon (Rn) leakage rates from the reservoirs. The invention further provides a method for branding sequestered carbon dioxide using perfluorcarbon tracers (PFTs) to show ownership.

  2. A study of leakage rates through mine seals in underground coal mines

    PubMed Central

    Schatzel, Steven J.; Krog, Robert B.; Mazzella, Andrew; Hollerich, Cynthia; Rubinstein, Elaine

    2015-01-01

    The National Institute for Occupational Safety and Health conducted a study on leakage rates through underground coal mine seals. Leakage rates of coal bed gas into active workings have not been well established. New seal construction standards have exacerbated the knowledge gap in our understanding of how well these seals isolate active workings near a seal line. At a western US underground coal mine, we determined seal leakage rates ranged from about 0 to 0.036 m3/s for seven 340 kPa seals. The seal leakage rate varied in essentially a linear manner with variations in head pressure at the mine seals. PMID:26322119

  3. An analysis of turbulent shear stresses in leakage flow through a bileaflet mechanical prostheses.

    PubMed

    Travis, Brandon R; Leo, Hwa L; Shah, Parina A; Frakes, David H; Yoganathan, Ajit P

    2002-04-01

    In this work, estimates of turbulence were made from pulsatile flow laser Doppler velocimetry measurements using traditional phase averaging and averaging after the removal of cyclic variation. These estimates were compared with estimates obtained from steady leakage flow LDV measurements and an analytical method. The results of these studies indicate that leakage jets which are free and planar in shape may be more unstable than other leakage jets, and that cyclic variation does not cause a gross overestimation of the Reynolds stresses at large distances from the leakage jet orifice.

  4. Suppressing Leakage in High Fidelity Single Qubit Gates for Superconducting Qubits

    NASA Astrophysics Data System (ADS)

    Chen, Z.; Kelly, J.; Quintana, C.; Barends, R.; Campbell, B.; Chen, Y.; Chiaro, B.; Dunsworth, A.; Fowler, A. G.; Lucero, E.; Jeffrey, E.; Megrant, A.; Mutus, J.; Neeley, M.; Neill, C.; O'Malley, P. J. J.; Roushan, P.; Sank, D.; Vainsencher, A.; Wenner, J.; White, T.; Korotkov, A. N.; Martinis, J. M.

    Recent results show that superconducting qubits are approaching the threshold for fault tolerant quantum error correction. However, leakage into non-qubit states remains a significant hurdle because leakage errors are highly detrimental for error correction schemes such as the surface code. I will demonstrate that with a simple addition to DRAG pulse shaping, leakage can be suppressed to the 10-5 level while simultaneously maintaining 10-3 gate fidelity. I will also show that the remaining leakage errors are due to heating of the qubit, suggesting further avenues for improvement. The work was supported by Google Inc., and by the NSFGRF under Grant No. DGE 1144085.

  5. Surface Monitoring of Leakage From Geologic CO2 Sequestration

    NASA Astrophysics Data System (ADS)

    Strazisar, B. R.; Klusman, R. W.; Wells, A. W.

    2003-12-01

    The capture of carbon dioxide (CO2) from large point sources and long term storage in geological formations has received much recent attention as a potential green house gas mitigation option. Among the proposed storage locations are active and depleted oil and natural gas reservoirs, unmineable coal seams, and deep saline aquifers. The success of any candidate storage location greatly depends on its ability to keep CO2 underground for a long period of time. In order to evaluate the success or failure of a CO2 storage operation, it is important to monitor injection sites to detect CO2 released at the surface. The U.S. Department of Energy has placed a high priority on the development of inexpensive, effective methods to measure, monitor, and verify long term sequestration of CO2 in geological sinks. Monitoring the leakage of CO2 is a challenging task, due to the small expected concentrations above a leaking reservoir as well as the relatively large background of CO2 present in the atmosphere. Another complication is the fact that CO2 continually diffuses from the soil into the atmosphere due to plant and microbial respiration. Any leak of CO2 from a reservoir would have to be differentiated from these other processes. In cooperation with the Texas Bureau of Economic Geology at the University of Texas, the National Energy Technology Laboratory is conducting a comprehensive surface monitoring effort at the site of a pilot scale injection project. In this project, approximately 4000 tons of CO2 will be injected into the Frio formation, a deep, non-petroleum bearing saline aquifer. Surface monitoring includes the detection of injected tracer molecules, direct measurement of CO2 soil flux, soil gas analysis, and carbon isotope analysis from soil gas CO2. These measurements, in conjunction with a parallel modeling effort and deep seismic surveys, will provide an accurate measure of the leak rate of CO2 to the surface (or an upper limit of leakage). Such an understanding

  6. Passive electrical monitoring and localization of fluid leakages from wells

    NASA Astrophysics Data System (ADS)

    Revil, A.; Mao, D.; Haas, A. K.; Karaoulis, M.; Frash, L.

    2015-02-01

    Electrokinetic phenomena are a class of cross-coupling phenomena involving the relative displacement between the pore water (together with the electrical diffuse layer) with respect to the solid phase of a porous material. We demonstrate that electrical fields of electrokinetic nature can be associated with fluid leakages from wells. These leakages can be remotely monitored and the resulting signals used to localize their causative source distribution both in the laboratory and in field conditions. The first laboratory experiment (Experiment #1) shows how these electrical fields can be recorded at the surface of a cement block during the leakage of a brine from a well. The measurements were performed with a research-grade medical electroencephalograph and were inverted using a genetic algorithm to localize the causative source of electrical current and therefore, localize the leak in the block. Two snapshots of electrical signals were used to show how the leak evolved over time. The second experiment (Experiment #2) was performed to see if we could localize a pulse water injection from a shallow well in field conditions in the case of a heterogeneous subsurface. We used the same equipment as in Experiment #1 and processed the data with a trend removal algorithm, picking the amplitude from 24 receiver channels just after the water injection. The amplitude of the electric signals changed from the background level indicating that a volume of water was indeed flowing inside the well into the surrounding soil and then along the well. We used a least-square inversion algorithm to invert a snapshot of the electrical potential data at the injection time to localize the source of the self-potential signals. The inversion results show positive potential anomalies in the vicinity of the well. For both experiments, forward numerical simulations of the problem using a finite element package were performed in order to assess the underlying physics of the causative source of the

  7. On leakage and seepage from geological carbon sequestration sites

    SciTech Connect

    Oldenburg, C.M.; Unger, A.J.A.; Hepple, R.P.; Jordan, P.D.

    2002-07-18

    Geologic carbon sequestration is one strategy for reducing the rate of increase of global atmospheric carbon dioxide (CO{sub 2} ) concentrations (IEA, 1997; Reichle, 2000). As used here, the term geologic carbon sequestration refers to the direct injection of supercritical CO{sub 2} deep into subsurface target formations. These target formations will typically be either depleted oil and gas reservoirs, or brine-filled permeable formations referred to here as brine formations. Injected CO{sub 2} will tend to be trapped by one or more of the following mechanisms: (1) permeability trapping, for example when buoyant supercritical CO{sub 2} rises until trapped by a confining caprock; (2) solubility trapping, for example when CO{sub 2} dissolves into the aqueous phase in water-saturated formations, or (3) mineralogic trapping, such as occurs when CO{sub 2} reacts to produce stable carbonate minerals. When CO{sub 2} is trapped in the subsurface by any of these mechanisms, it is effectively sequestered away from the atmosphere where it would otherwise act as a greenhouse gas. The purpose of this report is to summarize our work aimed at quantifying potential CO{sub 2} seepage due to leakage from geologic carbon sequestration sites. The approach we take is to present first the relevant properties of CO{sub 2} over the range of conditions from the deep subsurface to the vadose zone (Section 2), and then discuss conceptual models for how leakage might occur (Section 3). The discussion includes consideration of gas reservoir and natural gas storage analogs, along with some simple estimates of seepage based on assumed leakage rates. The conceptual model discussion provides the background for the modeling approach wherein we focus on simulating transport in the vadose zone, the last potential barrier to CO{sub 2} seepage (Section 4). Because of the potentially wide range of possible properties of actual future geologic sequestration sites, we carry out sensitivity analyses by

  8. Toxicity of ethacrynic acid in isolated rat hepatocytes.

    PubMed

    Yamamoto, K; Masubuchi, Y; Narimatsu, S; Kobayashi, S; Horie, T

    2002-04-01

    Ethacrynic acid, a loop diuretic drug, caused lipid peroxidation in isolated rat hepatocytes. The thiobarbituric acid reactive substances (TBARS) formation showed a good correlation with the leakage of glutamic-oxaloacetic acid transaminase (GOT) from the hepatocytes. The addition of antioxidants such as N, N'-diphenyl-p-phenylenediamine (DPPD) and promethazine to the isolated rat hepatocyte suspension containing ethacrynic acid prevented the lipid peroxidation and decreased the GOT leakage to some extent. SKF-525A inhibited the oxidative metabolism of ethacrynic acid and decreased the TBARS formation, suggesting that the lipid peroxidation was caused by the oxidative metabolism. The intracellular reduced glutathione markedly decreased in the hepatocyte suspension containing ethacrynic acid and the hepatocellular protein sulfhydryls were decreased, which was negatively correlated with the GOT leakage. Thus the ethacrynic acid-induced hepatotoxicity was found to be related to the lipid peroxidation and the decrease of cellular protein sulfhydryls.

  9. On Leakage from Geologic Storage Reservoirs of CO2

    SciTech Connect

    Pruess, Karsten

    2006-02-14

    Large amounts of CO2 would need to be injected underground to achieve a significant reduction of atmospheric emissions. The large areal extent expected for CO2 plumes makes it likely that caprock imperfections will be encountered, such as fault zones or fractures, which may allow some CO2 to escape from the primary storage reservoir. Leakage of CO2 could also occur along wellbores. Concerns with escape of CO2 from a primary geologic storage reservoir include (1) acidification of groundwater resources, (2) asphyxiation hazard when leaking CO2 is discharged at the land surface, (3) increase in atmospheric concentrations of CO2, and (4) damage from a high-energy, eruptive discharge (if such discharge is physically possible). In order to gain public acceptance for geologic storage as a viable technology for reducing atmospheric emissions of CO2, it is necessary to address these issues and demonstrate that CO2 can be injected and stored safely in geologic formations.

  10. Comprehensive failure analysis of leakage faults in bipolar transistors

    NASA Astrophysics Data System (ADS)

    Domengès, B.; Murray, H.; Schwindenhammer, P.; Imbert, G.

    2004-02-01

    The origin of a leakage current in several failed NPN bipolar transistors has been identified by complementary advanced failure analysis techniques. After precise localization of the failing area by photon emission microscopy and optical beam induced resistance change investigations, a focus ion beam technique was used to prepare thin lamellae adequate for transmission electron microscopy (TEM) study. Characterization of the related microstructure was performed by TEM and energy-dispersive spectrometry nanobeam analyses. It was identified as Ti-W containing trickle-like residue located at the surface of the spacers. Current-voltage measurements could be related to such structure defects and the involved conduction mechanism was identified as the Poole-Frenkel effect.

  11. [A mobile sensor for remote detection of natural gas leakage].

    PubMed

    Zhang, Shuai; Liu, Wen-qing; Zhang, Yu-jun; Kan, Rui-feng; Ruan, Jun; Wang, Li-ming; Yu, Dian-qiang; Dong, Jin-ting; Han, Xiao-lei; Cui, Yi-ben; Liu, Jian-guo

    2012-02-01

    The detection of natural gas pipeline leak becomes a significant issue for body security, environmental protection and security of state property. However, the leak detection is difficult, because of the pipeline's covering many areas, operating conditions and complicated environment. A mobile sensor for remote detection of natural gas leakage based on scanning wavelength differential absorption spectroscopy (SWDAS) is introduced. The improved soft threshold wavelet denoising was proposed by analyzing the characteristics of reflection spectrum. And the results showed that the signal to noise ratio (SNR) was increased three times. When light intensity is 530 nA, the minimum remote sensitivity will be 80 ppm x m. A widely used SWDAS can make quantitative remote sensing of natural gas leak and locate the leak source precisely in a faster, safer and more intelligent way.

  12. Highly sensitive optical sensor system for blood leakage detection

    NASA Astrophysics Data System (ADS)

    Ueda, Masahiro; Ishikawa, Kazuhiko; Jie, Chen; Sanae, Mizuno; Touma, Yasunori

    A highly sensitive method for the detection of blood leakage has been developed, and a practical sensor system for blood concentration measurement has been constructed. The present method is based on the attenuation of laser light by blood cells. The effects of the fluctuations of the incident laser light power are eliminated by normalizing the attenuated light intensity by the incident light intensity. A part of the incident laser light is reflected by a beam splitter mounted at the entrance of the test cell, of which the power is measured to provide base data for normalization. The optical path is extended to enhance sensitivity by using a pair of side mirrors. This multi-reflection method is very effective to increase sensitivity; the maximum sensitivity obtained for blood concentration is about 4 X 10 -6 by volume, which is significantly higher than that of the conventional sensors.

  13. Quench tank in-leakage diagnosis at St. Lucie

    SciTech Connect

    Price, J.E.; Au-Yang, M.K.; Beckner, D.A.; Vickery, A.N.

    1996-12-01

    In February 1995, leakage into the quench tank of the St. Lucie Nuclear Station Unit 1 was becoming an operational concern. This internal leak resulted in measurable increases in both the temperature and level of the quench tank water, and was so severe that, if the trend continued, plant shut down would be necessary. Preliminary diagnosis based on in-plant instrumentation indicated that any one of 11 valves might be leaking into the quench tank. This paper describes the joint effort by two teams of engineers--one from Florida Power & Light, the other from Framatome Technologies--to identify the sources of the leak, using the latest technology developed for valve diagnosis.

  14. Leakage currents in degraded multi-layer ceramic capacitors

    NASA Astrophysics Data System (ADS)

    Burton, L. C.

    1984-03-01

    Leakage currents in new and degraded X7R type multi-layer ceramic capacitors show both ohmic and space charge limited behavior. The near-3/2 power voltage characteristic (I proportional to V to the 3/2 power) of new devices can be attributed to electron emission from electrode points. The quadratic behavior (I proportional to V squared) for moderately degraded devices represents space charge limited emission from planar electrodes. This emission may evolve from the point emission due to resistivity decreases that occur in the emission region as a result of ion movement. For these currents, electrons are believed to be the dominant charge carriers. Neither Schottky nor Poole-Frenkel currents were identified.

  15. Moisture Risk in Unvented Attics Due to Air Leakage Paths

    SciTech Connect

    Prahl, D.; Shaffer, M.

    2014-11-01

    IBACOS completed an initial analysis of moisture damage potential in an unvented attic insulated with closed-cell spray polyurethane foam. To complete this analysis, the research team collected field data, used computational fluid dynamics to quantify the airflow rates through individual airflow (crack) paths, simulated hourly flow rates through the leakage paths with CONTAM software, correlated the CONTAM flow rates with indoor humidity ratios from Building Energy Optimization software, and used Warme und Feuchte instationar Pro two-dimensional modeling to determine the moisture content of the building materials surrounding the cracks. Given the number of simplifying assumptions and numerical models associated with this analysis, the results indicate that localized damage due to high moisture content of the roof sheathing is possible under very low airflow rates. Reducing the number of assumptions and approximations through field studies and laboratory experiments would be valuable to understand the real-world moisture damage potential in unvented attics.

  16. Moisture Risk in Unvented Attics Due to Air Leakage Paths

    SciTech Connect

    Prahl, D.; Shaffer, M.

    2014-11-01

    IBACOS completed an initial analysis of moisture damage potential in an unvented attic insulated with closed-cell spray polyurethane foam. To complete this analysis, the research team collected field data, used computational fluid dynamics to quantify the airflow rates through individual airflow (crack) paths, simulated hourly flow rates through the leakage paths with CONTAM software, correlated the CONTAM flow rates with indoor humidity ratios from Building Energy Optimization software, and used Wärme und Feuchte instationär Pro two-dimensional modeling to determine the moisture content of the building materials surrounding the cracks. Given the number of simplifying assumptions and numerical models associated with this analysis, the results indicate that localized damage due to high moisture content of the roof sheathing is possible under very low airflow rates. Reducing the number of assumptions and approximations through field studies and laboratory experiments would be valuable to understand the real-world moisture damage potential in unvented attics.

  17. A Study of Neutron Leakage in Finite Objects

    NASA Technical Reports Server (NTRS)

    Wilson, John W.; Slaba, Tony C.; Badavi, Francis F.; Reddell, Brandon D.; Bahadori, Amir A.

    2015-01-01

    A computationally efficient 3DHZETRN code capable of simulating High charge (Z) and Energy (HZE) and light ions (including neutrons) under space-like boundary conditions with enhanced neutron and light ion propagation was recently developed for simple shielded objects. Monte Carlo (MC) benchmarks were used to verify the 3DHZETRN methodology in slab and spherical geometry, and it was shown that 3DHZETRN agrees with MC codes to the degree that various MC codes agree among themselves. One limitation in the verification process is that all of the codes (3DHZETRN and three MC codes) utilize different nuclear models/databases. In the present report, the new algorithm, with well-defined convergence criteria, is used to quantify the neutron leakage from simple geometries to provide means of verifying 3D effects and to provide guidance for further code development.

  18. Structural and leakage integrity of tubes affected by circumferential cracking

    SciTech Connect

    Hernalsteen, P.

    1997-02-01

    In this paper the author deals with the notion that circumferential cracks are generally considered unacceptable. He argues for the need to differentiate two facets of such cracks: the issue of the size and growth rate of a crack; and the issue of the structural strength and leakage potential of the tube in the presence of the crack. In this paper the author tries to show that the second point is not a major concern for such cracks. The paper presents data on the structural strength or burst pressure characteristics of steam generator tubes derived from models and data bases of experimental work. He also presents a leak rate model, and compares the performance of circumferential and axial cracks as far as burst strength and leak rate. The final conclusion is that subject to improvement in NDE capabilities (sizing, detection, growth), that Steam Generator Defect Specific Management can be used to allow circumferentially degraded tubes to remain in service.

  19. Managing faecal incontinence or leakage: the Peristeen Anal Plug.

    PubMed

    Doherty, Willie

    Incontinence can be a devastating problem to many individuals. It is embarrassing and limiting socially, and prevents those with the problem from going about their day-to-day activities. People adopt coping strategies to manage the problem and those with urinary incontinence often look for containment products such as disposable pads or nappy-style products. These products have been developed using different absorbent materials and are accessible to sufferers in local supermarkets. Absorbency of the products has improved so that once wetted, they hold urine more easily. However, the same cannot be said for faecal incontinence management products and there are few that can be called upon to manage this devastating condition. The Peristeen Anal Plug, developed originally as the Conveen Anal Plug, stands alone in the search for a device to manage faecal incontinence or leakage.

  20. Compensation for booster leakage field in the Duke storage ring

    NASA Astrophysics Data System (ADS)

    Li, Wei; Hao, Hao; Mikhailov, Stepan F.; Popov, Victor; Li, Wei-Min; Wu, Ying. K.

    2017-01-01

    The High Intensity Gamma-ray Source (HIGS) at Duke University is an accelerator-driven Compton gamma-ray source, providing high flux gamma-ray beam from 1 MeV to 100 MeV for photo-nuclear physics research. The HIGS facility operates three accelerators, a linac pre-injector (0.16 GeV), a booster injector (0.16—1.2 GeV), and an electron storage ring (0.24—1.2 GeV). Because of the proximity of the booster injector to the storage ring, the magnetic field of the booster dipoles close to the ring can significantly alter the closed orbit in the storage ring being operated in the low energy region. This type of orbit distortion can be a problem for certain precision experiments which demand a high degree of energy consistency of the gamma-ray beam. This energy consistency can be achieved by maintaining consistent aiming of the gamma-ray beam, and therefore a steady electron beam orbit and angle at the Compton collision point. To overcome the booster leakage field problem, we have developed an orbit compensation scheme. This scheme is developed using two fast orbit correctors and implemented as a feedforward which is operated transparently together with the slow orbit feedback system. In this paper, we will describe the development of this leakage field compensation scheme, and report the measurement results, which demonstrate the effectiveness of the scheme. Supported by National Natural Science Foundation of China (11175180, 11475167) and US DOE (DE-FG02-97ER41033)

  1. SETI via Leakage from Light Sails in Exoplanetary Systems

    NASA Astrophysics Data System (ADS)

    Guillochon, James; Loeb, Abraham

    2015-10-01

    The primary challenge of rocket propulsion is the burden of needing to accelerate the spacecraft’s own fuel, resulting in only a logarithmic gain in maximum speed as propellant is added to the spacecraft. Light sails offer an attractive alternative in which fuel is not carried by the spacecraft, with acceleration being provided by an external source of light. By artificially illuminating the spacecraft with beamed radiation, speeds are only limited by the area of the sail, heat resistance of its material, and power use of the accelerating apparatus. In this paper, we show that leakage from a light sail propulsion apparatus in operation around a solar system analogue would be detectable. To demonstrate this, we model the launch and arrival of a microwave beam-driven light sail constructed for transit between planets in orbit around a single star, and find an optimal beam frequency on the order of tens of GHz. Leakage from these beams yields transients with flux densities of Jy and durations of tens of seconds at 100 pc. Because most travel within a planetary system would be conducted between the habitable worlds within that system, multiply transiting exoplanetary systems offer the greatest chance of detection, especially when the planets are in projected conjunction as viewed from Earth. If interplanetary travel via beam-driven light sails is commonly employed in our galaxy, this activity could be revealed by radio follow-up of nearby transiting exoplanetary systems. The expected signal properties define a new strategy in the search for extraterrestrial intelligence (SETI).

  2. SETI VIA LEAKAGE FROM LIGHT SAILS IN EXOPLANETARY SYSTEMS

    SciTech Connect

    Guillochon, James; Loeb, Abraham E-mail: aloeb@cfa.harvard.edu

    2015-10-01

    The primary challenge of rocket propulsion is the burden of needing to accelerate the spacecraft’s own fuel, resulting in only a logarithmic gain in maximum speed as propellant is added to the spacecraft. Light sails offer an attractive alternative in which fuel is not carried by the spacecraft, with acceleration being provided by an external source of light. By artificially illuminating the spacecraft with beamed radiation, speeds are only limited by the area of the sail, heat resistance of its material, and power use of the accelerating apparatus. In this paper, we show that leakage from a light sail propulsion apparatus in operation around a solar system analogue would be detectable. To demonstrate this, we model the launch and arrival of a microwave beam-driven light sail constructed for transit between planets in orbit around a single star, and find an optimal beam frequency on the order of tens of GHz. Leakage from these beams yields transients with flux densities of Jy and durations of tens of seconds at 100 pc. Because most travel within a planetary system would be conducted between the habitable worlds within that system, multiply transiting exoplanetary systems offer the greatest chance of detection, especially when the planets are in projected conjunction as viewed from Earth. If interplanetary travel via beam-driven light sails is commonly employed in our galaxy, this activity could be revealed by radio follow-up of nearby transiting exoplanetary systems. The expected signal properties define a new strategy in the search for extraterrestrial intelligence (SETI)

  3. Experimental determination of methane dissolution from simulated subsurface oil leakages

    NASA Astrophysics Data System (ADS)

    Sauthoff, W.; Peltzer, E. T.; Walz, P. M.; Brewer, P. G.

    2013-12-01

    Subsurface oil leakages and increased offshore drilling efforts have raised concern over the fate of hydrocarbon mixtures of oil and gas in ocean environments. Recent wellhead and pipeline failures in the Gulf of Mexico are extreme examples of this problem. Understanding the mechanism and rate of vertical transport of hydrocarbon chemical species is necessary to predict the environmental impact of subsurface leakages. In a series of controlled experiments, we carried out a deep-sea field experiment in Monterey Canyon to investigate the behavior of a gas-saturated liquid hydrocarbon mass rising from the seafloor. Aboard the R/V Rachel Carson, we used the ROV Ventana to transport a laboratory prepared volume of decane (C10H22) saturated with methane gas (CH4) to mimic a subsurface seafloor discharge. We released the oil and gas mixture into a vertically oriented open bottom glass tube followed by methane loss rate measurements both at discrete depths, and during rapid, continuous vehicle ascent from 800 to 100 m water depth to monitor changes in dissolution and bubble nucleation. Using laser Raman techniques and HD video we quantified the chemical state of the hydrocarbon fluid, including rate of methane gas dissolution. The primary methane Raman peak was readily observable within the decane C-H stretching complex. Variation in the amount of gas dissolved in the oil greatly influences oil plume density and in turn oil plume vertical rise rate. Our results show that the rise rate of the hydrocarbon mass significantly exceeds the rate at which the excess methane was lost by dissolution. This result implies that vertical transport of methane in the saturated hydrocarbon liquid phase can greatly exceed a gas bubble plume ascending the water column from a seafloor source. These results and observations may be applicable to improved understanding of the composition, distribution, and environmental fate of leaked hydrocarbon mixtures and inform remediation efforts.

  4. Mind the gap - tip leakage vortex in axial turbines

    NASA Astrophysics Data System (ADS)

    Dreyer, M.; Decaix, J.; Münch-Alligné, C.; Farhat, M.

    2014-03-01

    The tendency of designing large Kaplan turbines with a continuous increase of output power is bringing to the front the cavitation erosion issue. Due to the flow in the gap between the runner and the discharge ring, axial turbine blades may develop the so called tip leakage vortex (TLV) cavitation with negative consequences. Such vortices may interact strongly with the wake of guide vanes leading to their multiple collapses and rebounds. If the vortex trajectory remains close to the blade tip, these collapses may lead to severe erosion. One is still unable today to predict its occurrence and development in axial turbines with acceptable accuracy. Numerical flow simulations as well as the actual scale-up rules from small to large scales are unreliable. The present work addresses this problematic in a simplified case study representing TLV cavitation to better understand its sensitivity to the gap width. A Naca0009 hydrofoil is used as a generic blade in the test section of EPFL cavitation tunnel. A sliding mounting support allowing an adjustable gap between the blade tip and wall was manufactured. The vortex trajectory is visualized with a high speed camera and appropriate lighting. The three dimensional velocity field induced by the TLV is investigated using stereo particle image velocimetry. We have taken into account the vortex wandering in the image processing to obtain accurate measurements of the vortex properties. The measurements were performed in three planes located downstream of the hydrofoil for different values of the flow velocity, the incidence angle and the gap width. The results clearly reveal a strong influence of the gap width on both trajectory and intensity of the tip leakage vortex.

  5. The minimotif synthesis hypothesis for the origin of life

    PubMed Central

    Schiller, Martin R

    2017-01-01

    Several theories for the origin of life have gained widespread acceptance, led by primordial soup, chemical evolution, metabolism first, and the RNA world. However, while new and existing theories often address a key step, there is less focus on a comprehensive abiogenic continuum leading to the last universal common ancestor. Herein, I present the “minimotif synthesis” hypothesis unifying select origin of life theories with new and revised steps. The hypothesis is based on first principles, on the concept of selection over long time scales, and on a stepwise progression toward complexity. The major steps are the thermodynamically-driven origination of extant molecular specificity emerging from primordial soup leading to the rise of peptide catalysts, and a cyclic feed-forward catalytic diversification of compound and peptides in the primordial soup. This is followed by degenerate, semi-partially conservative peptide replication to pass on catalytic knowledge to progeny protocells. At some point during this progression, the emergence of RNA and selection could drive the separation of catalytic and genetic functions, allowing peptides and proteins to permeate the catalytic space, and RNA to encode higher fidelity information transfer. Translation may have emerged from RNA template driven organization and successive ligation of activated amino acids as a predecessor to translation. PMID:28083146

  6. The minimotif synthesis hypothesis for the origin of life.

    PubMed

    Schiller, Martin R

    2016-01-01

    Several theories for the origin of life have gained widespread acceptance, led by primordial soup, chemical evolution, metabolism first, and the RNA world. However, while new and existing theories often address a key step, there is less focus on a comprehensive abiogenic continuum leading to the last universal common ancestor. Herein, I present the "minimotif synthesis" hypothesis unifying select origin of life theories with new and revised steps. The hypothesis is based on first principles, on the concept of selection over long time scales, and on a stepwise progression toward complexity. The major steps are the thermodynamically-driven origination of extant molecular specificity emerging from primordial soup leading to the rise of peptide catalysts, and a cyclic feed-forward catalytic diversification of compound and peptides in the primordial soup. This is followed by degenerate, semi-partially conservative peptide replication to pass on catalytic knowledge to progeny protocells. At some point during this progression, the emergence of RNA and selection could drive the separation of catalytic and genetic functions, allowing peptides and proteins to permeate the catalytic space, and RNA to encode higher fidelity information transfer. Translation may have emerged from RNA template driven organization and successive ligation of activated amino acids as a predecessor to translation.

  7. Numerical studies on the performance of an aerosol respirator with faceseal leakage

    NASA Astrophysics Data System (ADS)

    Zaripov, S. K.; Mukhametzanov, I. T.; Grinshpun, S. A.

    2016-11-01

    We studied the efficiency of a facepiece filtering respirator (FFR) in presence of a measurable faceseal leakage using the previously developed model of a spherical sampler with porous layer. In our earlier study, the model was validated for a specific filter permeability value. In this follow-up study, we investigated the effect of permeability on the overall respirator performance accounting for the faceseal leakage. The Total Inward Leakage (TIL) was calculated as a function of the leakage-to-filter surface ratio and the particle diameter. A good correlation was found between the theoretical and experimental TIL values. The TIL value was shown to increase and the effect of particle size on TIL to decrease as the leakage-to- filter surface ratio grows. The model confirmed that within the most penetrating particle size range (∼50 nm) and at relatively low leakage-to-filter surface ratios, an FFR performs better (TIL is lower) when the filter has a lower permeability which should be anticipated as long as the flow through the filter represents the dominant particle penetration pathway. An increase in leak size causes the TIL to rise; furthermore, under certain leakage-to-filter surface ratios, TIL for ultrafine particles becomes essentially independent on the filter properties due to a greater contribution of the aerosol flow through the faceseal leakage. In contrast to the ultrafine fraction, the larger particles (e.g., 800 nm) entering a typical high- or medium-quality respirator filter are almost fully collected by the filter medium regardless of its permeability; at the same time, the fraction penetrated through the leakage appears to be permeability- dependent: higher permeability generally results in a lower pressure drop through the filter which increases the air flow through the filter at the expense of the leakage flow. The latter reduces the leakage effect thus improving the overall respiratory protection level. The findings of this study provide

  8. Epithelial ovarian cancer: testing the 'androgens hypothesis'.

    PubMed

    Olsen, Catherine M; Green, Adèle C; Nagle, Christina M; Jordan, Susan J; Whiteman, David C; Bain, Christopher J; Webb, Penelope M

    2008-12-01

    In 1998, Risch proposed a hypothesis for the pathogenesis of ovarian cancer relating to the role of androgens in stimulating epithelial cell proliferation. Although this hypothesis has been widely discussed, direct evidence to support it is scant. To address this issue, we have conducted a detailed analysis of factors possibly associated with high circulating levels of androgens, including polycystic ovary syndrome (PCOS), hirsutism and acne (all clinically associated with hyperandrogenism) using the data collected in an Australia-wide, population-based case-control study. Cases aged 18-79 years with a new diagnosis of invasive epithelial ovarian cancer (n=1276) or borderline malignant tumour (n=315) were identified through a network of clinics and cancer registries throughout Australia. Controls (n=1508) were selected from the National Electoral Roll. Women self-reported a history of PCOS, acne, hirsutism and also use of testosterone supplements or the androgenic medication Danazol. We found no evidence that a history of PCOS, acne or hirsutism was associated with ovarian cancer overall, or with specific subtypes, with the exception of serous borderline tumours that were positively associated with a history of PCOS (OR 2.6; 95% CI 1.0-6.1). Women who had ever used testosterone supplements had an increased risk of ovarian cancer (OR 3.7; 95% CI 1.1-12.0); however, use of the androgenic medication Danazol did not increase risk (OR 1.0; 95% CI 0.4-2.9). Overall, our results do not support the hypothesis that androgen-related disorders increase the risk of ovarian cancer.

  9. Hypothesis on how to measure electromagnetic hypersensitivity.

    PubMed

    Tuengler, Andreas; von Klitzing, Lebrecht

    2013-09-01

    Electromagnetic hypersensitivity (EHS) is an ill-defined term to describe the fact that people who experience health symptoms in the vicinity of electromagnetic fields (EMFs) regard them as causal for their complaints. Up to now most scientists assume a psychological cause for the suffering of electromagnetic hypersensitive individuals. This paper addresses reasons why most provocation studies could not find any association between EMF exposure and EHS and presents a hypothesis on diagnosis and differentiation of this condition. Simultaneous recordings of heart rate variability, microcirculation and electric skin potentials are used for classification of EHS. Thus, it could be possible to distinguish "genuine" electromagnetic hypersensitive individuals from those who suffer from other conditions.

  10. Grammatical equivalents of Palaeolithic tools: a hypothesis.

    PubMed

    Vieira, Antonio B

    2010-09-01

    In this article, language is considered as a behavioural trait evolving by means of natural selection, in co-evolution with the Palaeolithic tool industries. This perspective enables an analysis of the grammatical and syntactic equivalents of the multiple abilities and effects of lithic tools across the successive modes of their development and consider their influence in intra-group communication and the social biology of the hominine species concerned. The hypothesis is that grammatical equivalents inherent to stone tool work guide the evolution of language.

  11. Testing the gonadal regression-cytoprotection hypothesis.

    PubMed

    Crawford, B A; Spaliviero, J A; Simpson, J M; Handelsman, D J

    1998-11-15

    Germinal damage is an almost universal accompaniment of cancer treatment as the result of bystander damage to the testis from cytotoxic drugs and/or irradiation. Cancer treatment for the most common cancers of the reproductive age group in men has improved such that most are now treated with curative intent, and many others are treated with likelihood of prolonged survival, so that the preservation of fertility is an important component of posttreatment quality of life. This has led to the consideration of developing adjuvant treatments that may reduce the gonadal toxicity of cancer therapy. One dominant hypothesis has been based on the supposition that the immature testis was resistant to cytotoxin damage. Hence, if hormonal treatment were able to cause spermatogenic regression to an immature state via an effective withdrawal of gonadotrophin secretion, the testis might be maintained temporarily in a protected state during cytotoxin exposure. However, clinical studies have been disappointing but have also been unable to test the hypothesis definitively thus far, due to the inability to completely suppress gonadotrophin secretion. Similarly, experimental models have also given conflicting results and, at best, a modest cytoprotection. To definitively test this hypothesis experimentally, we used the fact that the functionally hpg mouse has complete gonadotrophin deficiency but can undergo the induction of full spermatogenesis by testosterone. Thus, if complete gonadotrophin deficiency were an advantage during cytotoxin exposure, then the hpg mouse should exhibit some degree of germinal protection against cytotoxin-induced damage. We therefore administered three different cytotoxins (200 mg/kg procarbazine, 9 mg/kg doxorubicin, 8 Gy of X irradiation) to produce a range of severity in testicular damage and mechanism of action to either phenotypically normal or hpg mice. Testis weight and homogenization-resistant spermatid numbers were measured to evaluate the

  12. Motion sickness: a cholinomimetic agent hypothesis.

    PubMed

    Sheehan, Scott E; Oman, Charles M; Duda, Kevin R

    2011-01-01

    Motion sickness has been defined as a set of physiological signs and symptoms produced as a result of prolonged sensory conflict in central nervous system vestibular centers. It has long been noted that the particular pattern of motion sickness signs and symptoms does not fit the conventional "fight or flight vs. rest and digest" autonomic synergy. We argue that most of the progression of symptoms is consistent with a new etiologic hypothesis: that an as-yet-unidentified ganglionic cholinomimetic agent is slowly released in proportion to sensory conflict. The agent accumulates systemically and stimulates the peripheral sympathetic and parasympathetic ganglia, the adrenal medulla, and potentiates the response of central cholinergic emetic pathways to the same conflict stimulus. The predominant effects of ganglionic stimulation on each autonomic organ, determined by resting tone, are selectively enhanced or inhibited by adrenal catecholamine release, producing the atypical pattern of autonomic changes seen in motion sickness. The adrenergic response may eventually also counter the central emetic drive. The hypothesis could be experimentally pursued via human and animal experiments employing a nicotinic antagonist that has both central and peripheral ganglionic actions such as mecamylamine.

  13. Advent of Continents: A New Hypothesis

    PubMed Central

    Tamura, Yoshihiko; Sato, Takeshi; Fujiwara, Toshiya; Kodaira, Shuichi; Nichols, Alexander

    2016-01-01

    The straightforward but unexpected relationship presented here relates crustal thickness to magma type in the Izu-Ogasawara (Bonin) and Aleutian oceanic arcs. Volcanoes along the southern segment of the Izu-Ogasawara arc and the western Aleutian arc (west of Adak) are underlain by thin crust (10–20 km). In contrast those along the northern segment of the Izu-Ogasawara arc and eastern Aleutian arc are underlain by crust ~35 km thick. Interestingly, andesite magmas dominate eruptive products from the former volcanoes and mostly basaltic lavas erupt from the latter. According to the hypothesis presented here, rising mantle diapirs stall near the base of the oceanic crust at depths controlled by the thickness of the overlying crust. Where the crust is thin, melting occurs at relatively low pressures in the mantle wedge producing andesitic magmas. Where the crust is thick, melting pressures are higher and only basaltic magmas tend to be produced. The implications of this hypothesis are: (1) the rate of continental crust accumulation, which is andesitic in composition, would have been greatest soon after subduction initiated on Earth, when most crust was thin; and (2) most andesite magmas erupted on continental crust could be recycled from “primary” andesite originally produced in oceanic arcs. PMID:27669662

  14. Inoculation Stress Hypothesis of Environmental Enrichment

    PubMed Central

    Crofton, Elizabeth J.; Zhang, Yafang; Green, Thomas A.

    2014-01-01

    One hallmark of psychiatric conditions is the vast continuum of individual differences in susceptibility vs. resilience resulting from the interaction of genetic and environmental factors. The environmental enrichment paradigm is an animal model that is useful for studying a range of psychiatric conditions, including protective phenotypes in addiction and depression models. The major question is how environmental enrichment, a non-drug and non-surgical manipulation, can produce such robust individual differences in such a wide range of behaviors. This paper draws from a variety of published sources to outline a coherent hypothesis of inoculation stress as a factor producing the protective enrichment phenotypes. The basic tenet suggests that chronic mild stress from living in a complex environment and interacting non-aggressively with conspecifics can inoculate enriched rats against subsequent stressors and/or drugs of abuse. This paper reviews the enrichment phenotypes, mulls the fundamental nature of environmental enrichment vs. isolation, discusses the most appropriate control for environmental enrichment, and challenges the idea that cortisol/corticosterone equals stress. The intent of the inoculation stress hypothesis of environmental enrichment is to provide a scaffold with which to build testable hypotheses for the elucidation of the molecular mechanisms underlying these protective phenotypes and thus provide new therapeutic targets to treat psychiatric/neurological conditions. PMID:25449533

  15. Advent of Continents: A New Hypothesis.

    PubMed

    Tamura, Yoshihiko; Sato, Takeshi; Fujiwara, Toshiya; Kodaira, Shuichi; Nichols, Alexander

    2016-09-27

    The straightforward but unexpected relationship presented here relates crustal thickness to magma type in the Izu-Ogasawara (Bonin) and Aleutian oceanic arcs. Volcanoes along the southern segment of the Izu-Ogasawara arc and the western Aleutian arc (west of Adak) are underlain by thin crust (10-20 km). In contrast those along the northern segment of the Izu-Ogasawara arc and eastern Aleutian arc are underlain by crust ~35 km thick. Interestingly, andesite magmas dominate eruptive products from the former volcanoes and mostly basaltic lavas erupt from the latter. According to the hypothesis presented here, rising mantle diapirs stall near the base of the oceanic crust at depths controlled by the thickness of the overlying crust. Where the crust is thin, melting occurs at relatively low pressures in the mantle wedge producing andesitic magmas. Where the crust is thick, melting pressures are higher and only basaltic magmas tend to be produced. The implications of this hypothesis are: (1) the rate of continental crust accumulation, which is andesitic in composition, would have been greatest soon after subduction initiated on Earth, when most crust was thin; and (2) most andesite magmas erupted on continental crust could be recycled from "primary" andesite originally produced in oceanic arcs.

  16. Advent of Continents: A New Hypothesis

    NASA Astrophysics Data System (ADS)

    Tamura, Yoshihiko; Sato, Takeshi; Fujiwara, Toshiya; Kodaira, Shuichi; Nichols, Alexander

    2016-09-01

    The straightforward but unexpected relationship presented here relates crustal thickness to magma type in the Izu-Ogasawara (Bonin) and Aleutian oceanic arcs. Volcanoes along the southern segment of the Izu-Ogasawara arc and the western Aleutian arc (west of Adak) are underlain by thin crust (10–20 km). In contrast those along the northern segment of the Izu-Ogasawara arc and eastern Aleutian arc are underlain by crust ~35 km thick. Interestingly, andesite magmas dominate eruptive products from the former volcanoes and mostly basaltic lavas erupt from the latter. According to the hypothesis presented here, rising mantle diapirs stall near the base of the oceanic crust at depths controlled by the thickness of the overlying crust. Where the crust is thin, melting occurs at relatively low pressures in the mantle wedge producing andesitic magmas. Where the crust is thick, melting pressures are higher and only basaltic magmas tend to be produced. The implications of this hypothesis are: (1) the rate of continental crust accumulation, which is andesitic in composition, would have been greatest soon after subduction initiated on Earth, when most crust was thin; and (2) most andesite magmas erupted on continental crust could be recycled from “primary” andesite originally produced in oceanic arcs.

  17. The Malaria-High Blood Pressure Hypothesis

    PubMed Central

    Smeeth, Liam; Cruickshank, J. Kennedy; Scott, J. Anthony G.

    2016-01-01

    Rationale: Several studies have demonstrated links between infectious diseases and cardiovascular conditions. Malaria and hypertension are widespread in many low- and middle-income countries, but the possible link between them has not been considered. Objective: In this article, we outline the basis for a possible link between malaria and hypertension and discuss how the hypothesis could be confirmed or refuted. Methods and Results: We reviewed published literature on factors associated with hypertension and checked whether any of these were also associated with malaria. We then considered various study designs that could be used to test the hypothesis. Malaria causes low birth weight, malnutrition, and inflammation, all of which are associated with hypertension in high-income countries. The hypothetical link between malaria and hypertension can be tested through the use of ecological, cohort, or Mendelian randomization studies, each of which poses specific challenges. Conclusions: Confirmation of the existence of a causative link with malaria would be a paradigm shift in efforts to prevent and control hypertension and would stimulate wider research on the links between infectious and noncommunicable disease. PMID:27151400

  18. Einstein's Revolutionary Light--Quantum Hypothesis

    NASA Astrophysics Data System (ADS)

    Stuewer, R. H.

    2006-03-01

    Albert Einstein's light-quantum paper was the only one of his great papers of 1905 that he himself called ``very revolutionary''. I sketch his arguments for light quanta, his analysis of the photoelectric effect, and his introduction of the wave-particle duality into physics in 1909. I show that Robert Andrews Millikan, in common with almost all physicists at the time, rejected Einstein's light-quantum hypothesis as an interpretation of his photoelectric-effect experiments of 1915. I then trace the complex experimental and theoretical route that Arthur Holly Compton followed between 1916 and 1922 that led to his discovery of the Compton effect, a discovery that Peter Debye also made virtually simultaneously and independently. Compton's discovery, however, was challenged on experimental grounds by William Duane and on theoretical grounds by Niels Bohr in the Bohr--Kramers--Slater theory of 1924, and only after that theory was disproved experimentally the following year by Walther Bothe and Hans Geiger in Berlin and by Compton and Alfred W. Simon in Chicago was Einstein's light-quantum hypothesis generally accepted by physicists.

  19. Investigations into the hypothesis of transgenic cannabis.

    PubMed

    Cascini, Fidelia

    2012-05-01

    The unusual concentration of cannabinoids recently found in marijuana samples submitted to the forensic laboratory for chemical analysis prompted an investigation into whether genetic modifications have been made to the DNA of Cannabis sativa L. to increase its potency. Traditional methods for the detection of genetically modified organisms (GMO) were used to analyze herbal cannabis preparations. Our analyses support the hypothesis that marijuana samples submitted to forensic laboratories and characterized by an abnormal level of Δ(9)-THC are the product of breeding selection rather than of transgenic modifications. Further, this research has shown a risk of false positive results associated with the poor quality of the seized samples and probably due to the contamination by other transgenic vegetable products. On the other hand, based on these data, a conclusive distinction between the hypothesis of GMO plant contamination and the other of genetic modification of cannabis cannot be made requiring further studies on comparative chemical and genetic analyses to find out an explanation for the recently detected increased potency of cannabis.

  20. Colloquium: Physics of the Riemann hypothesis

    NASA Astrophysics Data System (ADS)

    Schumayer, Dániel; Hutchinson, David A. W.

    2011-04-01

    Physicists become acquainted with special functions early in their studies. Consider our perennial model, the harmonic oscillator, for which we need Hermite functions, or the Laguerre functions in quantum mechanics. Here a particular number-theoretical function is chosen, the Riemann zeta function, and its influence on the realm of physics is examined and also how physics may be suggestive for the resolution of one of mathematics’ most famous unconfirmed conjectures, the Riemann hypothesis. Does physics hold an essential key to the solution for this more than 100-year-old problem? In this work numerous models from different branches of physics are examined, from classical mechanics to statistical physics, where this function plays an integral role. This function is also shown to be related to quantum chaos and how its pole structure encodes when particles can undergo Bose-Einstein condensation at low temperature. Throughout these examinations light is shed on how the Riemann hypothesis can highlight physics. Naturally, the aim is not to be comprehensive, but rather focusing on the major models and aim to give an informed starting point for the interested reader.

  1. Computation-distributed probability hypothesis density filter

    NASA Astrophysics Data System (ADS)

    Wang, Junjie; Zhao, Lingling; Su, Xiaohong; Shi, Chunmei; Ma, JiQuan

    2016-12-01

    Particle probability hypothesis density filtering has become a promising approach for multi-target tracking due to its capability of handling an unknown and time-varying number of targets in a nonlinear, non-Gaussian system. However, its computational complexity linearly increases with the number of obtained observations and the number of particles, which can be very time consuming, particularly when numerous targets and clutter exist in the surveillance region. To address this issue, we present a distributed computation particle probability hypothesis density(PHD) filter for target tracking. It runs several local decomposed particle PHD filters in parallel while processing elements. Each processing element takes responsibility for a portion of particles but all measurements and provides local estimates. A central unit controls particle exchange among the processing elements and specifies a fusion rule to match and fuse the estimates from different local filters. The proposed framework is suitable for parallel implementation. Simulations verify that the proposed method can significantly accelerate and maintain a comparative accuracy compared to the standard particle PHD filter.

  2. Learning-Related Changes in Adolescents' Neural Networks during Hypothesis-Generating and Hypothesis-Understanding Training

    ERIC Educational Resources Information Center

    Lee, Jun-Ki; Kwon, Yongju

    2012-01-01

    Fourteen science high school students participated in this study, which investigated neural-network plasticity associated with hypothesis-generating and hypothesis-understanding in learning. The students were divided into two groups and participated in either hypothesis-generating or hypothesis-understanding type learning programs, which were…

  3. Learning-Related Changes in Adolescents' Neural Networks During Hypothesis-Generating and Hypothesis-Understanding Training

    NASA Astrophysics Data System (ADS)

    Lee, Jun-Ki; Kwon, Yongju

    2010-11-01

    Fourteen science high school students participated in this study, which investigated neural-network plasticity associated with hypothesis-generating and hypothesis-understanding in learning. The students were divided into two groups and participated in either hypothesis-generating or hypothesis-understanding type learning programs, which were composed of 12 topics taught over a 12-week period. To measure change in student competence and brain networks, a paper & pencil test and an fMRI scanning session were administered before and after the training programs. Unlike the hypothesis-understanding group, a before and after training comparison for the hypothesis-generating group showed significantly strong changes in hypothesis explanation quotients and functional brain connectivity associated with hypothesis-generating. However, for the hypothesis-understanding group, the brain network related to hypothesis-understanding significantly strengthened, not from hypothesis-generating type learning, but from hypothesis-understanding type learning. These findings suggest that for hypothesis-generating and hypothesis-understanding there are at least two specialized brain network systems or processes at work in the brain. Furthermore, hypothesis-generating competence could be developed by appropriate training programs such as teaching by way of active hypothesis generation rather than present passive expository teaching practices.

  4. The Younger Dryas impact hypothesis: A requiem

    NASA Astrophysics Data System (ADS)

    Pinter, Nicholas; Scott, Andrew C.; Daulton, Tyrone L.; Podoll, Andrew; Koeberl, Christian; Anderson, R. Scott; Ishman, Scott E.

    2011-06-01

    The Younger Dryas (YD) impact hypothesis is a recent theory that suggests that a cometary or meteoritic body or bodies hit and/or exploded over North America 12,900 years ago, causing the YD climate episode, extinction of Pleistocene megafauna, demise of the Clovis archeological culture, and a range of other effects. Since gaining widespread attention in 2007, substantial research has focused on testing the 12 main signatures presented as evidence of a catastrophic extraterrestrial event 12,900 years ago. Here we present a review of the impact hypothesis, including its evolution and current variants, and of efforts to test and corroborate the hypothesis. The physical evidence interpreted as signatures of an impact event can be separated into two groups. The first group consists of evidence that has been largely rejected by the scientific community and is no longer in widespread discussion, including: particle tracks in archeological chert; magnetic nodules in Pleistocene bones; impact origin of the Carolina Bays; and elevated concentrations of radioactivity, iridium, and fullerenes enriched in 3He. The second group consists of evidence that has been active in recent research and discussions: carbon spheres and elongates, magnetic grains and magnetic spherules, byproducts of catastrophic wildfire, and nanodiamonds. Over time, however, these signatures have also seen contrary evidence rather than support. Recent studies have shown that carbon spheres and elongates do not represent extraterrestrial carbon nor impact-induced megafires, but are indistinguishable from fungal sclerotia and arthropod fecal material that are a small but common component of many terrestrial deposits. Magnetic grains and spherules are heterogeneously distributed in sediments, but reported measurements of unique peaks in concentrations at the YD onset have yet to be reproduced. The magnetic grains are certainly just iron-rich detrital grains, whereas reported YD magnetic spherules are

  5. Large eddy simulation of tip-leakage flow in an axial flow fan

    NASA Astrophysics Data System (ADS)

    Park, Keuntae; Choi, Haecheon; Choi, Seokho; Sa, Yongcheol; Kwon, Oh-Kyoung

    2016-11-01

    An axial flow fan with a shroud generates a complicated tip-leakage flow by the interaction of the axial flow with the fan blades and shroud near the blade tips. In this study, large eddy simulation is performed for tip-leakage flow in a forward-swept axial flow fan inside an outdoor unit of an air-conditioner, operating at the design condition of the Reynolds number of 547,000 based on the radius of blade tip and the tip velocity. A dynamic global model is used for a subgrid-scale model, and an immersed boundary method in a non-inertial reference frame is adopted. The present simulation clearly reveals the generation and evolution of tip-leakage vortex near the blade tip by the leakage flow. At the inception of the leakage vortex near the leading edge of the suction-side of the blade tip, the leakage vortex is composed of unsteady multiple vortices containing high-frequency fluctuations. As the leakage vortex develops downstream along a slant line toward the following blade, large and meandering movements of the leakage vortex are observed. Thus low-frequency broad peaks of velocity and pressure occur near the pressure surface. Supported by the KISTI Supercomputing Center (KSC-2016-C3-0027).

  6. 49 CFR 176.710 - Care following leakage or sifting of radioactive materials.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 2 2014-10-01 2014-10-01 false Care following leakage or sifting of radioactive... CARRIAGE BY VESSEL Detailed Requirements for Radioactive Materials § 176.710 Care following leakage or sifting of radioactive materials. (a) In case of fire, collision, or breakage involving any shipment...

  7. 49 CFR 176.710 - Care following leakage or sifting of radioactive materials.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 2 2012-10-01 2012-10-01 false Care following leakage or sifting of radioactive... CARRIAGE BY VESSEL Detailed Requirements for Radioactive Materials § 176.710 Care following leakage or sifting of radioactive materials. (a) In case of fire, collision, or breakage involving any shipment...

  8. 49 CFR 176.710 - Care following leakage or sifting of radioactive materials.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 2 2013-10-01 2013-10-01 false Care following leakage or sifting of radioactive... CARRIAGE BY VESSEL Detailed Requirements for Radioactive Materials § 176.710 Care following leakage or sifting of radioactive materials. (a) In case of fire, collision, or breakage involving any shipment...

  9. 49 CFR 176.710 - Care following leakage or sifting of radioactive materials.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 2 2011-10-01 2011-10-01 false Care following leakage or sifting of radioactive... CARRIAGE BY VESSEL Detailed Requirements for Radioactive Materials § 176.710 Care following leakage or sifting of radioactive materials. (a) In case of fire, collision, or breakage involving any shipment...

  10. 40 CFR 86.166-12 - Method for calculating emissions due to air conditioning leakage.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... to air conditioning leakage. 86.166-12 Section 86.166-12 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) CONTROL OF EMISSIONS FROM NEW AND IN-USE HIGHWAY... for calculating emissions due to air conditioning leakage. This section describes procedures used...

  11. A conservation planning approach to mitigate the impacts of leakage from protected area networks.

    PubMed

    Bode, Michael; Tulloch, Ayesha I T; Mills, Morena; Venter, Oscar; Ando, Amy W

    2015-06-01

    Protected area networks are designed to restrict anthropogenic pressures in areas of high biodiversity. Resource users respond by seeking to replace some or all of the lost resources from locations elsewhere in the landscape. Protected area networks thereby perturb the pattern of human pressures by displacing extractive effort from within protected areas into the broader landscape, a process known as leakage. The negative effects of leakage on conservation outcomes have been empirically documented and modeled using homogeneous descriptions of conservation landscapes. Human resource use and biodiversity vary greatly in space, however, and a theory of leakage must describe how this heterogeneity affects the magnitude, pattern, and biodiversity impacts of leakage. We combined models of household utility, adaptive human foraging, and biodiversity conservation to provide a bioeconomic model of leakage that accounts for spatial heterogeneity. Leakage had strong and divergent impacts on the performance of protected area networks, undermining biodiversity benefits but mitigating the negative impacts on local resource users. When leakage was present, our model showed that poorly designed protected area networks resulted in a substantial net loss of biodiversity. However, the effects of leakage can be mitigated if they are incorporated ex-ante into the conservation planning process. If protected areas are coupled with nonreserve policy instruments such as market subsidies, our model shows that the trade-offs between biodiversity and human well-being can be further and more directly reduced.

  12. Estimating the environmental and resource costs of leakage in water distribution systems: A shadow price approach.

    PubMed

    Molinos-Senante, María; Mocholí-Arce, Manuel; Sala-Garrido, Ramon

    2016-10-15

    Water scarcity is one of the main problems faced by many regions in the XXIst century. In this context, the need to reduce leakages from water distribution systems has gained almost universal acceptance. The concept of sustainable economic level of leakage (SELL) has been proposed to internalize the environmental and resource costs within economic level of leakage calculations. However, because these costs are not set by the market, they have not often been calculated. In this paper, the directional-distance function was used to estimate the shadow price of leakages as a proxy of their environmental and resource costs. This is a pioneering approach to the economic valuation of leakage externalities. An empirical application was carried out for the main Chilean water companies. The estimated results indicated that for 2014, the average shadow price of leakages was approximately 32% of the price of the water delivered. Moreover, as a sensitivity analysis, the shadow prices of the leakages were calculated from the perspective of the water companies' managers and the regulator. The methodology and findings of this study are essential for supporting the decision process of reducing leakage, contributing to the improvement of economic, social and environmental efficiency and sustainability of urban water supplies.

  13. 47 CFR 76.611 - Cable television basic signal leakage performance criteria.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 47 Telecommunication 4 2010-10-01 2010-10-01 false Cable television basic signal leakage...) BROADCAST RADIO SERVICES MULTICHANNEL VIDEO AND CABLE TELEVISION SERVICE Technical Standards § 76.611 Cable television basic signal leakage performance criteria. (a) No cable television system shall commence...

  14. 47 CFR 76.611 - Cable television basic signal leakage performance criteria.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 47 Telecommunication 4 2012-10-01 2012-10-01 false Cable television basic signal leakage...) BROADCAST RADIO SERVICES MULTICHANNEL VIDEO AND CABLE TELEVISION SERVICE Technical Standards § 76.611 Cable television basic signal leakage performance criteria. (a) No cable television system shall commence...

  15. 47 CFR 76.611 - Cable television basic signal leakage performance criteria.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 47 Telecommunication 4 2014-10-01 2014-10-01 false Cable television basic signal leakage...) BROADCAST RADIO SERVICES MULTICHANNEL VIDEO AND CABLE TELEVISION SERVICE Technical Standards § 76.611 Cable television basic signal leakage performance criteria. (a) No cable television system shall commence...

  16. 47 CFR 76.611 - Cable television basic signal leakage performance criteria.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 47 Telecommunication 4 2013-10-01 2013-10-01 false Cable television basic signal leakage...) BROADCAST RADIO SERVICES MULTICHANNEL VIDEO AND CABLE TELEVISION SERVICE Technical Standards § 76.611 Cable television basic signal leakage performance criteria. (a) No cable television system shall commence...

  17. 40 CFR 86.1867-12 - CO2 credits for reducing leakage of air conditioning refrigerant.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... lower global warming potential. LeakScore means the annual refrigerant leakage rate determined according....1 grams/year for systems using only electric compressors). GWPREF means the global warming potential... with a lower global warming potential. LeakScore means the annual refrigerant leakage rate...

  18. 40 CFR 86.1867-12 - CO2 credits for reducing leakage of air conditioning refrigerant.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... refrigerant with a lower global warming potential. LeakScore means the annual refrigerant leakage rate... (or 4.1 grams/year for systems using only electric compressors). GWPREF means the global warming... with a lower global warming potential. LeakScore means the annual refrigerant leakage rate...

  19. Non-destructive method for inward leakage detection of a plate evaporator

    NASA Astrophysics Data System (ADS)

    Hribernik, Ales

    2007-05-01

    A new non-destructive method was developed for the detection of refrigerant leakage at an evaporator's inflow. Nitrogen and oxygen gas were successively blown through the evaporator. A gas analyser was applied at the outflow of the evaporator and the oxygen concentration measured. It was possible to detect any leakage by investigating the oxygen concentration-time history diagram.

  20. Uncertainty Analysis for Assessing Leakage Through Water Tunnels: A Case from Nepal Himalaya

    NASA Astrophysics Data System (ADS)

    Panthi, Krishna Kanta; Nilsen, Bjørn

    2010-09-01

    Water leakage problems in unlined or shotcrete lined water tunnels are not new issues. In many occasions severe water leakage problems have been faced that not only have reduced the stability of the rock mass, but also have caused valuable water to be lost from it, causing safety risk as well as huge economic loss to the projects. Hence, making tunnels water tight plays an important role in improving stability and safety of underground excavations. The real challenge is however accurate prediction and quantification of possible water leakage, so that cost consequences can be incorporated during planning of a water conveying tunnel project. The main purposes of this paper are to analyze extensive data on leakage test carried out through exploratory drillhole used to define the need for pre-injection grouting of Khimti headrace tunnel and to carry out probabilistic approach of uncertainty analysis based on relationship established between leakage, hydrostatic head and selected Q-value parameters. The authors believe that the new approach regarding uncertainty analysis of leakage presented in this paper will improve the understanding of leakage characteristics of the rock mass, and hope this will lead to a better understanding concerning quantification of possible water leakage from unlined and shotcrete lined water tunnels.

  1. Approaches to informed consent for hypothesis-testing and hypothesis-generating clinical genomics research

    PubMed Central

    2012-01-01

    Background Massively-parallel sequencing (MPS) technologies create challenges for informed consent of research participants given the enormous scale of the data and the wide range of potential results. Discussion We propose that the consent process in these studies be based on whether they use MPS to test a hypothesis or to generate hypotheses. To demonstrate the differences in these approaches to informed consent, we describe the consent processes for two MPS studies. The purpose of our hypothesis-testing study is to elucidate the etiology of rare phenotypes using MPS. The purpose of our hypothesis-generating study is to test the feasibility of using MPS to generate clinical hypotheses, and to approach the return of results as an experimental manipulation. Issues to consider in both designs include: volume and nature of the potential results, primary versus secondary results, return of individual results, duty to warn, length of interaction, target population, and privacy and confidentiality. Summary The categorization of MPS studies as hypothesis-testing versus hypothesis-generating can help to clarify the issue of so-called incidental or secondary results for the consent process, and aid the communication of the research goals to study participants. PMID:23046515

  2. A hypothesis on Microthrix parvicella proliferation in biological nutrient removal activated sludge systems with selector tanks.

    PubMed

    Noutsopoulos, Constantinos; Mamais, Daniel; Andreadakis, Andreas; Stams, Alfons

    2012-05-01

    The objective of this study was to evaluate the ability of Microthrix parvicella for long-chain fatty acids uptake under anaerobic, anoxic, and aerobic conditions as well as its ability to utilize volatile fatty acids and long-chain fatty acids under anoxic and aerobic conditions. According to the results, a hypothesis on the competition between floc-forming microorganisms and M. parvicella for long-chain fatty acids uptake under aerobic, anoxic, and anaerobic conditions was formulated. According to this hypothesis, M. parvicella exhibits similar long-chain fatty acids uptake capacity with floc-forming microorganisms even at relatively high floc loading values that are very often imposed at selector tanks. Following this hypothesis, the failure of selector tanks to provide for an effective M. parvicella control is evidenced. Based on the experimental results, the ability of M. parvicella to utilize long-chain fatty acids with rates comparable to those of floc formers, even in anoxic conditions, in conjunction with its lower acetate utilization rates, provides a good explanation regarding its preference to slowly biodegradable organic carbon compounds.

  3. A two-dimensional simulation of plasma leakage due to dengue infection

    NASA Astrophysics Data System (ADS)

    Nuraini, N.; Windarto, Jayanti, Swarna; Soewono, Edy

    2014-03-01

    Dengue Hemorrhagic Fever (DHF) is a disease caused by Dengue virus infection. One major characteristic in a patient with DHF is the occurrence of plasma leakage. Plasma leakage is a consequence of the immune system mechanism which activates cytokine. As a result, permeability of vascular will increase. Another characteristic in a DHF patient is hypoalbuminea (decreasing of albumin concentration). Plasma leakage can be modelled by constructing mathematical model of albumin concentration in plasma blood due to increasing of cytokine. In this paper, decreasing of albumin concentration in blood plasma is modelled using diffusion equation. In addition, two-dimensional numerical simulations of albumin concentration are also presented. From the simulation, it is found that the greater leakage rate or the wider leakage area, the greater decreasing albumin concentration will be. Furthermore, when time t increases, the albumin concentration decreases to zero.

  4. Insulation Resistance and Leakage Currents in Low-Voltage Ceramic Capacitors with Cracks

    NASA Technical Reports Server (NTRS)

    Teverovsky, Alexander A.

    2014-01-01

    Measurement of insulation resistance (IR) in multilayer ceramic capacitors (MLCCs) is considered a screening technique that ensures the dielectric is defect-free. This work analyzes the effectiveness of this technique for revealing cracks in ceramic capacitors. It is shown that absorption currents prevail over the intrinsic leakage currents during standard IR measurements at room temperature. Absorption currents, and consequently IR, have a weak temperature dependence, increase linearly with voltage (before saturation), and are not sensitive to the presence of mechanical defects. In contrary, intrinsic leakage currents increase super-linearly with voltage and exponentially with temperature (activation energy is in the range from 0.6 eV to 1.1 eV). Leakage currents associated with the presence of cracks have a weaker dependence on temperature and voltage compared to the intrinsic leakage currents. For this reason, intrinsic leakage currents prevail at high temperatures and voltages, thus masking the presence of defects.

  5. Investigative techniques used to locate the liquid hydrogen leakage on the Space Shuttle Main Propulsion System

    NASA Technical Reports Server (NTRS)

    Hammock, William R., Jr.; Cota, Phillip E., Jr.; Rosenbaum, Bernard J.; Barrett, Michael J.

    1991-01-01

    Standard leak detection methods at ambient temperature have been developed in order to prevent excessive leakage from the Space Shuttle liquid oxygen and liquid hydrogen Main Propulsion System. Unacceptable hydrogen leakage was encountered on the Columbia and Atlantis flight vehicles in the summer of 1990 after the standard leak check requirements had been satisfied. The leakage was only detectable when the fuel system was exposed to subcooled liquid hydrogen during External Tank loading operations. Special instrumentation and analytical tools were utilized during a series of propellant tanking tests in order to identify the sources of the hydrogen leakage. After the leaks were located and corrected, the physical characteristics of the leak sources were analyzed in an effort to understand how the discrepancies were introduced and why the leakage had evaded the standard leak detection methods. As a result of the post-leak analysis, corrective actions and leak detection improvements have been implemented in order to preclude a similar incident.

  6. Insulation Resistance and Leakage Currents in Low-Voltage Ceramic Capacitors with Cracks

    NASA Technical Reports Server (NTRS)

    Teverovsky, Alexander A.

    2016-01-01

    Measurement of insulation resistance (IR) in multilayer ceramic capacitors (MLCCs) is considered a screening technique that ensures the dielectric is defect-free. This work analyzes the effectiveness of this technique for revealing cracks in ceramic capacitors. It is shown that absorption currents prevail over the intrinsic leakage currents during standard IR measurements at room temperature. Absorption currents, and consequently IR, have a weak temperature dependence, increase linearly with voltage (before saturation), and are not sensitive to the presence of mechanical defects. In contrary, intrinsic leakage currents increase super-linearly with voltage and exponentially with temperature (activation energy is in the range from 0.6 eV to 1.1 eV). Leakage currents associated with the presence of cracks have a weaker dependence on temperature and voltage compared to the intrinsic leakage currents. For this reason, intrinsic leakage currents prevail at high temperatures and voltages, thus masking the presence of defects.

  7. Pumping-induced leakage in a bounded aquifer: An example of a scale-invariant phenomenon

    USGS Publications Warehouse

    Butler, J.J.; Tsou, M.-S.

    2003-01-01

    A new approach is presented for calculation of the volume of pumping-induced leakage entering an aquifer as a function of time. This approach simplifies the total leakage calculation by extending analytical-based methods developed for infinite systems to bounded aquifers of any size. The simplification is possible because of the relationship between drawdown and leakage in aquifers laterally bounded by impermeable formations. This relationship produces a scale-invariant total leakage; i.e., the volume of leakage as a function of time does not change with the size of the aquifer or with the location of the pumping well. Two examples and image well theory are used to demonstrate and prove, respectively, the generality of this interesting phenomenon.

  8. Conversion efficiency of an energy harvester based on resonant tunneling through quantum dots with heat leakage.

    PubMed

    Kano, Shinya; Fujii, Minoru

    2017-03-03

    We study the conversion efficiency of an energy harvester based on resonant tunneling through quantum dots with heat leakage. Heat leakage current from a hot electrode to a cold electrode is taken into account in the analysis of the harvester operation. Modeling of electrical output indicates that a maximum heat leakage current is not negligible because it is larger than that of the heat current harvested into electrical power. A reduction of heat leakage is required in this energy harvester in order to obtain efficient heat-to-electrical conversion. Multiple energy levels of a quantum dot can increase the output power of the harvester. Heavily doped colloidal semiconductor quantum dots are a possible candidate for a quantum-dot monolayer in the energy harvester to reduce heat leakage, scaling down device size, and increasing electrical output via multiple discrete energy levels.

  9. Conversion efficiency of an energy harvester based on resonant tunneling through quantum dots with heat leakage

    NASA Astrophysics Data System (ADS)

    Kano, Shinya; Fujii, Minoru

    2017-03-01

    We study the conversion efficiency of an energy harvester based on resonant tunneling through quantum dots with heat leakage. Heat leakage current from a hot electrode to a cold electrode is taken into account in the analysis of the harvester operation. Modeling of electrical output indicates that a maximum heat leakage current is not negligible because it is larger than that of the heat current harvested into electrical power. A reduction of heat leakage is required in this energy harvester in order to obtain efficient heat-to-electrical conversion. Multiple energy levels of a quantum dot can increase the output power of the harvester. Heavily doped colloidal semiconductor quantum dots are a possible candidate for a quantum-dot monolayer in the energy harvester to reduce heat leakage, scaling down device size, and increasing electrical output via multiple discrete energy levels.

  10. Study on detecting leachate leakage of municipal solid waste landfill site.

    PubMed

    Liu, Jiangang; Cao, Xianxian; Ai, Yingbo; Zhou, Dongdong; Han, Qiting

    2015-06-01

    The article studies the detection of the leakage passage of leachate in a waste landfill dam. The leachate of waste landfill has its own features, like high conductivity, high chroma and an increasing temperature, also, the horizontal flow velocity of groundwater on the leakage site increases. This article proposes a comprehensive tracing method to identify the leakage site of an impermeable membrane by using these features. This method has been applied to determine two leakage sites of the Yahu municipal solid waste landfill site in Pingshan District, Shenzhen, China, which shows that there are two leachate leakage passages in the waste landfill dam A between NZK-2 and NZK-3, and between NZK-6 and NZK-7.

  11. Air Leakage of US Homes: Regression Analysis and Improvements from Retrofit

    SciTech Connect

    Chan, Wanyu R.; Joh, Jeffrey; Sherman, Max H.

    2012-08-01

    LBNL Residential Diagnostics Database (ResDB) contains blower door measurements and other diagnostic test results of homes in United States. Of these, approximately 134,000 single-family detached homes have sufficient information for the analysis of air leakage in relation to a number of housing characteristics. We performed regression analysis to consider the correlation between normalized leakage and a number of explanatory variables: IECC climate zone, floor area, height, year built, foundation type, duct location, and other characteristics. The regression model explains 68% of the observed variability in normalized leakage. ResDB also contains the before and after retrofit air leakage measurements of approximately 23,000 homes that participated in weatherization assistant programs (WAPs) or residential energy efficiency programs. The two types of programs achieve rather similar reductions in normalized leakage: 30% for WAPs and 20% for other energy programs.

  12. Barriers to seeking care for accidental bowel leakage: a qualitative study

    PubMed Central

    Rogers, Rebecca G.; Wise, Meg E.

    2016-01-01

    Introduction and hypothesis Fewer than 50 % of women with urinary incontinence (UI) and 30 % of women with accidental bowel leakage (ABL) seek care. We sought to describe barriers to care seeking for ABL to inform development of an instrument to measure these barriers. Methods We recruited women with ABL with varied prior care-seeking experiences to participate in focus groups and cognitive interviews so we could understand factors that may have prevented or delayed care seeking. Focus groups continued until thematic saturation was reached using conventional content analysis. Final themes were established and characterized by comparing within and across the focus groups and with previously described UI and ABL care-seeking barriers. Cognitive interviews were confirmatory. Results Thirty-nine women (aged 46–85) participated in six focus groups and ten cognitive interviews; 89 % were white, 8 % African American, and 3 % Latina. We identified 12 barriers to seeking care for ABL: (1) Lack of knowledge about the condition; (2) Lack of knowledge about treatment; (3) Fear of testing/treatment; (4) Normative thinking; (5) Avoidance/ denial; (6) Life impact; (7) Embarrassment/shame; (8) Self-blame; (9) Stigma; (10) Isolation; (11) Provider barriers; (12) Access limitations. These 12 barriers encompassed three overarching themes: the internalized self in relation to ABL; perceptions about ABL and its treatments; and interaction with the healthcare system. Conclusions ABL care-seeking barriers are similar to those described for UI, with the notable addition of lack of knowledge that ABL is a medical condition experienced by others. Interventions to promote access to effective treatments for ABL should include information about prevalence and treatability. PMID:27844123

  13. The Criticality Hypothesis in Neural Systems

    NASA Astrophysics Data System (ADS)

    Karimipanah, Yahya

    There is mounting evidence that neural networks of the cerebral cortex exhibit scale invariant dynamics. At the larger scale, fMRI recordings have shown evidence for spatiotemporal long range correlations. On the other hand, at the smaller scales this scale invariance is marked by the power law distribution of the size and duration of spontaneous bursts of activity, which are referred as neuronal avalanches. The existence of such avalanches has been confirmed by several studies in vitro and in vivo, among different species and across multiple scales, from spatial scale of MEG and EEG down to single cell resolution. This prevalent scale free nature of cortical activity suggests the hypothesis that the cortex resides at a critical state between two phases of order (short-lasting activity) and disorder (long-lasting activity). In addition, it has been shown, both theoretically and experimentally, that being at criticality brings about certain functional advantages for information processing. However, despite the plenty of evidence and plausibility of the neural criticality hypothesis, still very little is known on how the brain may leverage such criticality to facilitate neural coding. Moreover, the emergent functions that may arise from critical dynamics is poorly understood. In the first part of this thesis, we review several pieces of evidence for the neural criticality hypothesis at different scales, as well as some of the most popular theories of self-organized criticality (SOC). Thereafter, we will focus on the most prominent evidence from small scales, namely neuronal avalanches. We will explore the effect of adaptation and how it can maintain scale free dynamics even at the presence of external stimuli. Using calcium imaging we also experimentally demonstrate the existence of scale free activity at the cellular resolution in vivo. Moreover, by exploring the subsampling issue in neural data, we will find some fundamental constraints of the conventional methods

  14. Characterization of CO2 leakage into the freshwater body

    NASA Astrophysics Data System (ADS)

    Singh, Ashok; Delfs, Jens-Olaf; Shao, Habing; Kolditz, Olaf

    2013-04-01

    Current research into Carbon dioxide Capture and Storage (CCS) is dominated by improving the CO2 storage capacity. However, potential leakage of CO2 can cause environmental problems, particularly if freshwater resources are nearby. In this regards, it is important to understand the chemistry of CO2 and the water system. CO2 leakage across the fluid interface (CO2 and water) is controlled by the difference in the partial pressure of CO2 in the storage and in the freshwater body. Once the CO2 is in solution, it equilibrates with the bicarbonate and carbonate ions. According to Millero (1994)such a system can be characterized by two parameters out of the four: total alkalinity (TA), total carbonate (TCO2), fugacity of CO2(fCO2) and pH. In the present modeling study, we are interested in the (i) CO2 leakage into a freshwater body (while injecting CO2 for storage) through an inclined fracture and (ii) characterization of the system by measuring fugacity of CO2 and pH. According to work presented by Singh et al. (2012), about 31% of injected CO2 leaks into the freshwater body. Solubility of CO2 in water follows Henry's law, while the Henry constant, K0 is calculated by an empirical relation developed by Murray and Riley (1971), which is a function of salinity and temperature. According to our results, pH and fugacity both appear to be a linear function of temperature. To simulate the discussed problem, a corresponding numerical module has been developed for multi-component fluid flow coupled with heat and mass transport processes. Governing equations and Volume Translated Peng-Robinson equations of state are implemented within the object-oriented finite element code OpenGeoSys (Kolditz et al., 2012; www.opengeosys.org). Primary variables are pressure, temperature and salinity which are obtained by solving the governing equations in a monolithic way The governing equations are discretized spatially within the context of a Galerkin approach, whereas the temporal

  15. Possible association between celiac disease and bacterial transglutaminase in food processing: a hypothesis.

    PubMed

    Lerner, Aaron; Matthias, Torsten

    2015-08-01

    The incidence of celiac disease is increasing worldwide, and human tissue transglutaminase has long been considered the autoantigen of celiac disease. Concomitantly, the food industry has introduced ingredients such as microbial transglutaminase, which acts as a food glue, thereby revolutionizing food qualities. Several observations have led to the hypothesis that microbial transglutaminase is a new environmental enhancer of celiac disease. First, microbial transglutaminase deamidates/transamidates glutens such as the endogenous human tissue transglutaminase. It is capable of crosslinking proteins and other macromolecules, thereby changing their antigenicity and resulting in an increased antigenic load presented to the immune system. Second, it increases the stability of protein against proteinases, thus diminishing foreign protein elimination. Infections and the crosslinked nutritional constituent gluten and microbial transglutaminase increase the permeability of the intestine, where microbial transglutaminases are necessary for bacterial survival. The resulting intestinal leakage allows more immunogenic foreign molecules to induce celiac disease. The increased use of microbial transglutaminase in food processing may promote celiac pathogenesis ex vivo, where deamidation/transamidation starts, possibly explaining the surge in incidence of celiac disease. If future research substantiates this hypothesis, the findings will affect food product labeling, food additive policies of the food industry, and consumer health education.

  16. Possible association between celiac disease and bacterial transglutaminase in food processing: a hypothesis

    PubMed Central

    Matthias, Torsten

    2015-01-01

    The incidence of celiac disease is increasing worldwide, and human tissue transglutaminase has long been considered the autoantigen of celiac disease. Concomitantly, the food industry has introduced ingredients such as microbial transglutaminase, which acts as a food glue, thereby revolutionizing food qualities. Several observations have led to the hypothesis that microbial transglutaminase is a new environmental enhancer of celiac disease. First, microbial transglutaminase deamidates/transamidates glutens such as the endogenous human tissue transglutaminase. It is capable of crosslinking proteins and other macromolecules, thereby changing their antigenicity and resulting in an increased antigenic load presented to the immune system. Second, it increases the stability of protein against proteinases, thus diminishing foreign protein elimination. Infections and the crosslinked nutritional constituent gluten and microbial transglutaminase increase the permeability of the intestine, where microbial transglutaminases are necessary for bacterial survival. The resulting intestinal leakage allows more immunogenic foreign molecules to induce celiac disease. The increased use of microbial transglutaminase in food processing may promote celiac pathogenesis ex vivo, where deamidation/transamidation starts, possibly explaining the surge in incidence of celiac disease. If future research substantiates this hypothesis, the findings will affect food product labeling, food additive policies of the food industry, and consumer health education. PMID:26084478

  17. A Reassessment of the Mars Ocean Hypothesis

    NASA Technical Reports Server (NTRS)

    Parker, T. J.

    2004-01-01

    Initial work on the identification and mapping of potential ancient shorelines on Mars was based on Viking Orbiter image data (Parker et al., 1987, 1989, 1993). The Viking Orbiters were designed to locate landing site for the two landers and were not specifically intended to map the entire planet. Fortunately, they mapped the entire planet. Unfortunately, they did so at an average resolution of greater than 200m/pixel. Higher resolution images, even mosaics of interesting regions, are available, but relatively sparse. Mapping of shorelines on Earth requires both high-resolution aerial photos or satellite images and good topographic information. Three significant sources of additional data from missions subsequent to Viking are useful for reassessing the ocean hypothesis. These are: MGS MOC images; MGS MOLA topography; Odyssey THEMIS IR and VIS images; and MER surface geology at Meridiani and Gusev. Okay, my mistake: Four.

  18. The hexagon hypothesis: Six disruptive scenarios.

    PubMed

    Burtles, Jim

    2015-01-01

    This paper aims to bring a simple but effective and comprehensive approach to the development, delivery and monitoring of business continuity solutions. To ensure that the arguments and principles apply across the board, the paper sticks to basic underlying concepts rather than sophisticated interpretations. First, the paper explores what exactly people are defending themselves against. Secondly, the paper looks at how defences should be set up. Disruptive events tend to unfold in phases, each of which invites a particular style of protection, ranging from risk management through to business continuity to insurance cover. Their impact upon any business operation will fall into one of six basic scenarios. The hexagon hypothesis suggests that everyone should be prepared to deal with each of these six disruptive scenarios and it provides them with a useful benchmark for business continuity.

  19. Vessel Connectivity Using Murray’s Hypothesis

    PubMed Central

    Jiang, Yifeng; Zhuang, Zhen W.; Sinusas, Albert J.; Staib, Lawrence H.; Papademetris, Xenophon

    2012-01-01

    We describe a new method for vascular image analysis that incorporates a generic physiological principle to estimate vessel connectivity, which is a key issue in reconstructing complete vascular trees from image data. We follow Murray’s hypothesis of the minimum work principle to formulate the problem as an optimization problem. This principle reflects a global property of any vascular network, in contrast to various local geometric properties adopted as constraints previously. We demonstrate the effectiveness of our method using a set of microCT mouse coronary images. It is shown that the performance of our method has a statistically significant improvement over the widely adopted minimum spanning tree methods that rely on local geometric constraints. PMID:22003740

  20. N-Terminal Hypothesis for Alzheimer's Disease.

    PubMed

    Murray, Brian; Sharma, Bhanushee; Belfort, Georges

    2017-03-15

    Although the amyloid (abeta peptide, Aβ) hypothesis is 25 years old, is the dominant model of Alzheimer's disease (AD) pathogenesis, and guides the development of potential treatments, it is still controversial. One possible reason is a lack of a mechanistic path from the cleavage products of the amyloid precursor protein (APP) such as soluble Aβ monomer and soluble molecular fragments to the deleterious effects on synaptic form and function. From a review of the recent literature and our own published work including aggregation kinetics and structural morphology, Aβ clearance, molecular simulations, long-term potentiation measurements with inhibition binding, and the binding of a commercial monoclonal antibody, aducanumab, we hypothesize that the N-terminal domains of neurotoxic Aβ oligomers are implicated in causing the disease.

  1. Large numbers hypothesis. II - Electromagnetic radiation

    NASA Technical Reports Server (NTRS)

    Adams, P. J.

    1983-01-01

    This paper develops the theory of electromagnetic radiation in the units covariant formalism incorporating Dirac's large numbers hypothesis (LNH). A direct field-to-particle technique is used to obtain the photon propagation equation which explicitly involves the photon replication rate. This replication rate is fixed uniquely by requiring that the form of a free-photon distribution function be preserved, as required by the 2.7 K cosmic radiation. One finds that with this particular photon replication rate the units covariant formalism developed in Paper I actually predicts that the ratio of photon number to proton number in the universe varies as t to the 1/4, precisely in accord with LNH. The cosmological red-shift law is also derived and it is shown to differ considerably from the standard form of (nu)(R) - const.

  2. The intermediate distance hypothesis of biological invasions.

    PubMed

    Seebens, Hanno; Essl, Franz; Blasius, Bernd

    2017-02-01

    Biological invasions are a worldwide phenomenon, but the global flows between native and alien regions have rarely been investigated in a cross-taxonomic study. We therefore lack a thorough understanding of the global patterns of alien species spread. Using native and alien ranges of 1380 alien species, we show that the number of alien species follows a hump-shaped function of geographic distance. We observe distinct variations in the relationship between alien species exchanges and distance among taxonomic groups, which relate to the taxa-specific dispersal modes and their pathways of introduction. We formulate a simple statistical model, combining trade volume and biogeographic dissimilarity, which reproduces the observed pattern in good agreement with reported data and even captures variations among taxonomic groups. This study demonstrates the universality of the intermediate distance hypothesis of alien species spread across taxonomic groups, which will help to improve the predictability of new alien species arrivals.

  3. Effect of Dehydration on Leakage and Membrane Structure in Lotus corniculatus L. Seeds.

    PubMed

    McKersie, B D; Stinson, R H

    1980-08-01

    Membrane damage as a result of dehydration was studied in Lotus corniculatus L. cv. Carroll seeds which had been pregerminated for 0, 12, and 24 hours prior to dehydration. During reimbibition, desiccation-tolerant (0- and 12-hour) seeds leaked relatively low quantities of all solutes (total electrolytes, potassium, phosphate, sugar, amino acid, and protein). Desiccation-sensitive (24-hour) seeds leaked higher levels, but evidence of selective permeability remained. Membrane damage was not manifested as a complete removal of the diffusion barrier, although its permeability properties were dramatically altered. Consequently, the plasmalemma was not ruptured or torn by the dehydration treatment, but a more subtle structural alteration occurred.The possibility that seed membranes form a hexagonal rather than a lamellar phase at moisture contents below 20% was investigated by x-ray diffraction. Phospholipids were extracted from desiccation-tolerant (0-hour) and desiccation-sensitive (24-hour) seeds and hydrated to 5, 10, 20, and 40% water. This phospholipid-water system was examined using low-and wide-angle x-ray diffraction and was found to be exclusively lamellar, even at 5% water. Consequently, membrane damage and the leakage of cytoplasmic solutes from seeds cannot be explained by the formation of a hexagonal phase by membrane phospholipids.

  4. Immediate Reduction of Salmonella enterica Serotype Typhimurium Viability via Membrane Destabilization following Exposure to Multiple-Hurdle Treatments with Heated, Acidified Organic Acid Salt Solutions▿†

    PubMed Central

    Milillo, S. R.; Martin, E.; Muthaiyan, A.; Ricke, S. C.

    2011-01-01

    The antimicrobial activity of organic acids in combination with nonchemical treatments was evaluated for inactivation of Salmonella enterica serotype Typhimurium within 1 min. It was observed that the effectiveness of the multiple-hurdle treatments was temperature (P ≤ 0.05) and pH (P ≤ 0.05) dependent and corresponded to the degree of organic acid lipophilicity (sodium acetate being least effective and sodium propionate being the most effective). This led to the hypothesis that the loss in viability was due at least in part to cell membrane disruption. Evaluation of osmotic response, potassium ion leakage, and transmission electron micrographs confirmed treatment effects on the cell membrane. Interestingly, all treatments, even those with no effect on viability, such as with sodium acetate, resulted in measurable cellular stress. Microarray experiments explored the specific response of S. Typhimurium to sodium acetate and sodium propionate, the most similar of the tested treatments in terms of pKa and ionic strength, and found little difference in the changes in gene expression following exposure to either, despite their very different effects on viability. Taken together, the results reported support our hypothesis that treatment with heated, acidified, organic acid salt solutions for 1 min causes loss of S. Typhimurium viability at least in part by membrane damage and that the degree of effectiveness can be correlated with lipophilicity of the organic acid. Overall, the data presented here indicate that a combined thermal, acidified sodium propionate treatment can provide an effective antimicrobial treatment against Salmonella. PMID:21478311

  5. Agulhas leakage dynamics affects decadal variability in Atlantic overturning circulation.

    PubMed

    Biastoch, A; Böning, C W; Lutjeharms, J R E

    2008-11-27

    Predicting the evolution of climate over decadal timescales requires a quantitative understanding of the dynamics that govern the meridional overturning circulation (MOC). Comprehensive ocean measurement programmes aiming to monitor MOC variations have been established in the subtropical North Atlantic (RAPID, at latitude 26.5 degrees N, and MOVE, at latitude 16 degrees N) and show strong variability on intraseasonal to interannual timescales. Observational evidence of longer-term changes in MOC transport remains scarce, owing to infrequent sampling of transoceanic sections over past decades. Inferences based on long-term sea surface temperature records, however, supported by model simulations, suggest a variability with an amplitude of +/-1.5-3 Sv (1 Sv = 10(6) m(3) s(-1)) on decadal timescales in the subtropics. Such variability has been attributed to variations of deep water formation in the sub-arctic Atlantic, particularly the renewal rate of Labrador Sea Water. Here we present results from a model simulation that suggest an additional influence on decadal MOC variability having a Southern Hemisphere origin: dynamic signals originating in the Agulhas leakage region at the southern tip of Africa. These contribute a MOC signal in the tropical and subtropical North Atlantic that is of the same order of magnitude as the northern source. A complete rationalization of observed MOC changes therefore also requires consideration of signals arriving from the south.

  6. Rotordynamic and leakage characteristics of a 4-stage brush seal

    NASA Astrophysics Data System (ADS)

    Conner, K. J.; Childs, D. W.

    1992-12-01

    Experimental results are presented for the direct and cross-coupled stiffness and damping coefficients as well as the leakage performance for a 4-stage brush seal. Variable test parameters include the inlet pressure, pressure ratio, shaft speed, fluid prerotation, and seal spacing. Direct damping is shown to increase with running speed; otherwise, the rotordynamic coefficients are relatively insensitive to changes in the test parameters. Cross-coupled stiffness is generally unchanged by increasing the inlet tangential velocity to the seals, suggesting that the brush seal is not affected by inlet swirl. Direct stiffness is shown to increase with frequency; however, the magnitudes of direct stiffness are always positive. Cross-coupled stiffness increases slightly with frequency; yet not as drastically as direct stiffness. Comparisons of test results for the 4-stage brush seal with an 8-cavity labyrinth showed superior rotordynamics performance for the brush seal; viz., large values for direct stiffness and lower values for the (destabilizing) cross-coupled stiffness coefficient. The damping for brush seals is smaller, but comparable to labyrinth seals. The whirl-frequency ratio is always smaller for the brush seal.

  7. Degradation of Leakage Currents and Reliability Prediction for Tantalum Capacitors

    NASA Technical Reports Server (NTRS)

    Teverovsky, Alexander

    2016-01-01

    Two types of failures in solid tantalum capacitors, catastrophic and parametric, and their mechanisms are described. Analysis of voltage and temperature reliability acceleration factors reported in literature shows a wide spread of results and requires more investigation. In this work, leakage currents in two types of chip tantalum capacitors were monitored during highly accelerated life testing (HALT) at different temperatures and voltages. Distributions of degradation rates were approximated using a general log-linear Weibull model and yielded voltage acceleration constants B = 9.8 +/- 0.5 and 5.5. The activation energies were Ea = 1.65 eV and 1.42 eV. The model allows for conservative estimations of times to failure and was validated by long-term life test data. Parametric degradation and failures are reversible and can be annealed at high temperatures. The process is attributed to migration of charged oxygen vacancies that reduce the barrier height at the MnO2/Ta2O5 interface and increase injection of electrons from the MnO2 cathode. Analysis showed that the activation energy of the vacancies' migration is 1.1 eV.

  8. Feasibility study of tank leakage mitigation using subsurface barriers

    SciTech Connect

    Treat, R.L.; Peters, B.B.; Cameron, R.J.; McCormak, W.D.; Trenkler, T.; Walters, M.F.; Rouse, J.K.; McLaughlin, T.J.; Cruse, J.M.

    1994-09-21

    The US Department of Energy (DOE) has established the Tank Waste Remediation System (TWRS) to satisfy manage and dispose of the waste currently stored in the underground storage tanks. The retrieval element of TWRS includes a work scope to develop subsurface impermeable barriers beneath SSTs. The barriers could serve as a means to contain leakage that may result from waste retrieval operations and could also support site closure activities by facilitating cleanup. Three types of subsurface barrier systems have emerged for further consideration: (1) chemical grout, (2) freeze walls, and (3) desiccant, represented in this feasibility study as a circulating air barrier. This report contains analyses of the costs and relative risks associated with combinations retrieval technologies and barrier technologies that from 14 alternatives. Eight of the alternatives include the use of subsurface barriers; the remaining six nonbarrier alternative are included in order to compare the costs, relative risks and other values of retrieval with subsurface barriers. Each alternative includes various combinations of technologies that can impact the risks associated with future contamination of the groundwater beneath the Hanford Site to varying degrees. Other potential risks associated with these alternatives, such as those related to accidents and airborne contamination resulting from retrieval and barrier emplacement operations, are not quantitatively evaluated in this report.

  9. Leakage in roots coronally sealed with different temporary fillings.

    PubMed

    Barthel, C R; Strobach, A; Briedigkeit, H; Göbel, U B; Roulet, J F

    1999-11-01

    This study was aimed at determining the ability of different coronal temporary fillings to prevent corono-apical penetration of bacteria. A total of 103 human teeth, including three controls, were instrumented, obturated with gutta-percha, coronally sealed with either Cavit, Intermediate Restorative Material (IRM), glass-ionomer cement, Cavit/glass-ionomer cement, or IRM/glass-ionomer cement, respectively. Each root was fixed with wax between two chambers: the coronal chamber harboring soy broth with 10(8) colony-forming units of Streptococcus mutans/ml, the apical chamber containing sterile soy broth. The latter was checked daily for turbidity, indicating corono-apical penetration of bacteria. The Cavit group, the IRM group, and the Cavit/glass-ionomer cement group showed significantly more leakage than the glass-ionomer cement group of the IRM/glass-ionomer cement group. If a sample leaked, all except one (IRM/glass-ionomer cement) leaked before day 12. This in vitro study seems to indicate that only glass-ionomer cement and IRM combined with glass-ionomer cement may prevent bacterial penetration to the periapex of root-filled teeth over a 1-month period.

  10. Simulation of magnetic flux leakage: Application to tube inspection

    NASA Astrophysics Data System (ADS)

    Prémel, Denis; Fnaeich, E. A.; Djafa, S.; Pichon, L.; Trillon, A.; Bisiaux, B.

    2012-05-01

    The detection of flaws in steel pipes using Magnetic Flux Leakage (MFL) consists in detecting magnetic flux leaks outside the pipe, either with a magnetic sensor or with an induction coil, while the pipe is rotating. In the Vallourec group, many NDT units use MFL for testing ferromagnetic pipes. In order to improve the performances of flaw detection, CEA LIST and the Vallourec Research Aulnoye (VRA) group are collaborating on MFL modelling. The aim is to be able to perform parametric studies thanks to a fast 3D numerical model dedicated to MFL systems. A simplified 2D geometry has already been derived for the development of first simulation tools. When considering the B-H curve of ferromagnetic materials, the non-linear magnetostatic problem can be solved with the generalized boundary element method (BEMG), which comes to the evaluation of two equivalent scalar potentials: the surface charge density and the volume charge density. When applying the Galerkin method for the discretization of integral equations, the particularity of this numerical model lies in the implementation of high order basis functions for the interpolation of the scalar unknowns. This paper presents some first numerical results for the numerical validation of the semi-analytical model.

  11. Tasman Leakage of intermediate waters as inferred from Argo floats

    NASA Astrophysics Data System (ADS)

    Rosell-Fieschi, Miquel; Rintoul, Stephen R.; Gourrion, Jeröme; Pelegrí, Josep L.

    2013-10-01

    use Argo float trajectories to infer ocean current velocity at the sea surface and 1000 dbar near Australia. The East Australian Current flows southward along the east coast of Australia at both surface and intermediate levels, but only the intermediate waters leak round the southern tip of Tasmania and cross the Great Australian Bight. We calculate the transport of Antarctic Intermediate Water (AAIW) between the southern Australian coast and the Antarctic Circumpolar Current (ACC) as the velocity at 1000 dbar times the layer thickness. Between March 2006 and December 2012, the Eulerian AAIW transport through 147°E ranges between 0 and 12.0 sverdrup (Sv). The mean Tasman Leakage of intermediate waters from the Pacific Ocean into the Indian Ocean, obtained using all Argo data until March 2013, is 3.8 ± 1.3 Sv. The mean intermediate water transport into the Indian Ocean through 115°E increases to 5.2 ± 1.8 Sv due to contributions from the westward recirculation of ACC waters.

  12. Investigation of Underground Hydrocarbon Leakage using Ground Penetrating Radar

    NASA Astrophysics Data System (ADS)

    Srigutomo, Wahyu; Trimadona; Agustine, Eleonora

    2016-08-01

    Ground Penetrating Radar (GPR) survey was carried out in several petroleum plants to investigate hydrocarbon contamination beneath the surface. The hydrocarbon spills are generally recognized as Light Non-Aqueous Phase Liquids (LNAPL) if the plume of leakage is distributed in the capillary fringe above the water table and as Dense Non-Aqueous Phase Liquids (DNAPL) if it is below the water table. GPR antennas of 200 MHz and 400 MHz were deployed to obtain clear radargrams until 4 m deep. In general, the interpreted radargram sections indicate the presence of surface concrete layer, the compacted silty soill followed by sand layer and the original clayey soil as well as the water table. The presence of hydrocarbon plumes are identified as shadow zones (radar velocity and intensity contrasts) in the radargram that blur the layering pattern with different intensity of reflected signal. Based on our results, the characteristic of the shadow zones in the radargram is controlled by several factors: types of hydrocarbon (fresh or bio-degraded), water moisture in the soil, and clay content which contribute variation in electrical conductivity and dielectric constants of the soil.

  13. Prediction of paravalvular leakage after transcatheter aortic valve implantation.

    PubMed

    Di Martino, Luigi F M; Vletter, Wim B; Ren, Ben; Schultz, Carl; Van Mieghem, Nicolas M; Soliman, Osama I I; Di Biase, Matteo; de Jaegere, Peter P; Geleijnse, Marcel L

    2015-10-01

    Significant paravalvular leakage (PVL) after transcatheter aortic valve implantation (TAVI) is related to patient mortality. Predicting the development of PVL has focused on computed tomography (CT) derived variables but literature targeting CoreValve devices is limited, controversial, and did not make use of standardized echocardiographic methods. The study included 164 consecutive patients with severe aortic stenosis that underwent TAVI with a Medtronic CoreValve system©, with available pre-TAVI CT and pre-discharge transthoracic echocardiography. The predictive value for significant PVL of the CT-derived Agatston score, aortic annulus size and eccentricity, and "cover index" was assessed, according to both echocardiographic Valve Academic Research Consortium (VARC) criteria and angiographic Sellers criteria. Univariate predictors for more than mild PVL were the maximal diameter of the aortic annulus size (for both angiographic and echocardiographic assessment of PVL), cover index (for echocardiographic assessment of PVL only), and Agatston score (for both angiographic and echocardiographic assessment of PVL). The aortic annulus eccentricity index was not predicting PVL. At multivariate analysis, Agatston score was the only independent predictor for both angiographic and echocardiographic assessment of PVL. Agatston score is the only independent predictor of PVL regardless of the used imaging technique for the definition of PVL.

  14. Effects of switch leakages upon Nimbus-7 SMMR calibration

    NASA Technical Reports Server (NTRS)

    Han, Daesoo; Kim, Seung T.

    1988-01-01

    A calibration model for the Nimbus 7 Scanning Multichannel Microwave Radiometer (SMMR) is studied. This model not only removes major drawbacks of the current calibration model but also helps in the understanding of the performance degradation of the aging instrument. The current Nimbus 7 SMMR calibration algorithm was derived without considering the interference effect between the two orthogonally polarized signals merging at a ferrite polarization selector switch. The resulting calibrated brightness temperatures, considered as a function of scan angle, are not symmetric around scan angle = 0. However, neither the origin of the asymmetry nor the manner in which the two orthogonal components are mixed has been fully understood. The new calibration model proposed incorporates all the leakage factors associated with the ferrite switches along the signal paths. The resulting calibration equations clarify how the orthogonal components of surface brightness are coupled at radiometers. As a consequence, the origin of the asymmetry is clearly identified and explained. In addition, the feasibility of absolute calibration using in-orbit data is discussed.

  15. Effects of switch leakages upon Nimbus-7 SMMR calibration

    NASA Technical Reports Server (NTRS)

    Han, Daesoo; Kim, Seung T.

    1988-01-01

    A calibration model for the Nimbus-7 Scanning Multichannel Microwave Radiometer (SMMR) is studied. This model not only removes major drawbacks of the current calibration model but also helps us understand the performance degradation of the aging instrument. The current Nimbus-7 SMMR calibration algorithm was derived without considering the interference effect between the two orthogonally polarized signals merging at a ferrite polarization selector switch. The resulting calibrated brightness temperatures, considered as a function of scan angle phi, are not symmetric around phi=0. However, neither the origin of the asymmetry nor the manner in which the two orthogonal components are mixed is fully understood. The proposed calibration model incorporates all the leakage factors associated with the ferrite switches along the signal paths. The resulting calibration equations clarify how the orthogonal components of surface brightness are coupled at radiometers. As a consequence, the origin of the asymmetry is clearly identified and explained. In addition, the feasibility of absolute calibration using in-orbit data is discussed.

  16. Rotation otolith tilt-translation reinterpretation (ROTTR) hypothesis: a new hypothesis to explain neurovestibular spaceflight adaptation.

    PubMed

    Merfeld, Daniel M

    2003-01-01

    Normally, the nervous system must process ambiguous graviceptor (e.g., otolith) cues to estimate tilt and translation. The neural processes that help perform these estimation processes must adapt upon exposure to weightlessness and readapt upon return to Earth. In this paper we present a review of evidence supporting a new hypothesis that explains some aspects of these adaptive processes. This hypothesis, which we label the rotation otolith tilt-translation reinterpretation (ROTTR) hypothesis, suggests that the neural processes resulting in spaceflight adaptation include deterioration in the ability of the nervous system to use rotational cues to help accurately estimate the relative orientation of gravity ("tilt"). Changes in the ability to estimate gravity then also influence the ability of the nervous system to estimate linear acceleration ("translation"). We explicitly hypothesize that such changes in the ability to estimate "tilt" and "translation" will be measurable upon return to Earth and will, at least partially, explain the disorientation experienced when astronauts return to Earth. In this paper, we present the details and implications of ROTTR, review data related to ROTTR, and discuss the relationship of ROTTR to the influential otolith tilt-translation reinterpretation (OTTR) hypothesis as well as discuss the distinct differences between ROTTR and OTTR.

  17. Hypothesis driven assessment of an NMR curriculum

    NASA Astrophysics Data System (ADS)

    Cossey, Kimberly

    The goal of this project was to develop a battery of assessments to evaluate an undergraduate NMR curriculum at Penn State University. As a chemical education project, we sought to approach the problem of curriculum assessment from a scientific perspective, while remaining grounded in the education research literature and practices. We chose the phrase hypothesis driven assessment to convey this process of relating the scientific method to the study of educational methods, modules, and curricula. We began from a hypothesis, that deeper understanding of one particular analytical technique (NMR) will increase undergraduate students' abilities to solve chemical problems. We designed an experiment to investigate this hypothesis, and data collected were analyzed and interpreted in light of the hypothesis and several related research questions. The expansion of the NMR curriculum at Penn State was funded through the NSF's Course, Curriculum, and Laboratory Improvement (CCLI) program, and assessment was required. The goal of this project, as stated in the grant proposal, was to provide NMR content in greater depth by integrating NMR modules throughout the curriculum in physical chemistry, instrumental, and organic chemistry laboratory courses. Hands-on contact with the NMR spectrometer and NMR data and repeated exposure of the analytical technique within different contexts (courses) were unique factors of this curriculum. Therefore, we maintained a focus on these aspects throughout the evaluation process. The most challenging and time-consuming aspect of any assessment is the development of testing instruments and methods to provide useful data. After key variables were defined, testing instruments were designed to measure these variables based on educational literature (Chapter 2). The primary variables measured in this assessment were: depth of understanding of NMR, basic NMR knowledge, problem solving skills (HETCOR problem), confidence for skills used in class (within

  18. Enhanced ground bounce noise reduction in a low-leakage CMOS multiplier

    NASA Astrophysics Data System (ADS)

    Verma, Bipin Kumar; Akashe, Shyam; Sharma, Sanjay

    2015-09-01

    In this paper, various parameters are used to reduce leakage power, leakage current and noise margin of circuits to enhance their performance. A multiplier is proposed with low-leakage current and low ground bounce noise for the microprocessor, digital signal processors (DSP) and graphics engines. The ground bounce noise problem appears when a conventional power-gating circuit transits from sleep-to-active mode. This paper discusses a reduction in leakage current in the stacking power-gating technique by three modes - sleep, active and sleep-to-active. The simulation results are performed on a 4 × 4 carry-save multiplier for leakage current, active power, leakage power and ground bounce noise, and comparison made for different nanoscales. Ground bounce noise is limited to 90%. The leakage current of the circuit is decimated up to 80% and the active power is reduced to 31%. We performed simulations using cadence virtuoso 180 and 45 nm at room temperature at various supply voltages.

  19. Preoperative Nutritional Therapy Reduces the Risk of Anastomotic Leakage in Patients with Crohn's Disease Requiring Resections

    PubMed Central

    Guo, Zhen; Guo, Dong; Gong, Jianfeng; Zhu, Weiming; Zuo, Lugen; Sun, Jing; Li, Ning; Li, Jieshou

    2016-01-01

    Background. The rate of anastomotic leakage is high in surgeries for Crohn's disease, and therefore a temporary diverting stoma is often needed. We conducted this study to investigate whether preoperative nutritional therapy could reduce the risk of anastomotic leakage while decreasing the frequency of temporary stoma formation. Methods. This was a retrospective study. Patients requiring bowel resections due to Crohn's disease were reviewed. The rate of anastomotic leakage and temporary diverting stoma was compared between patients who received preoperative nutritional therapy and those on a normal diet before surgery. Possible predictive factors for anastomotic leakage were also analyzed. Results. One hundred and fourteen patients undergoing 123 surgeries were included. Patients in nutritional therapy (NT) group had a significantly lower level of C-reactive protein on the day before surgery. Patients in NT group suffered less anastomotic leakage (2.3% versus 17.9%, P = 0.023) and less temporary diverting stoma (22.8% versus 40.9%, P = 0.036). Serum albumin of the day before surgery ≤35 g/L and preoperative nutritional therapy were identified as factors which independently affected the rate of anastomotic leakage. Conclusion. Preoperative nutritional therapy reduced the risk of anastomotic leakage and the frequency of temporary diverting stoma formation in patients with Crohn's disease requiring resections. PMID:26858749

  20. Modeling and analysis of sub-surface leakage current in nano-MOSFET under cutoff regime

    NASA Astrophysics Data System (ADS)

    Swami, Yashu; Rai, Sanjeev

    2017-02-01

    The high leakage current in nano-meter regimes is becoming a significant portion of power dissipation in nano-MOSFET circuits as threshold voltage, channel length, and gate oxide thickness are scaled down to nano-meter range. Precise leakage current valuation and meticulous modeling of the same at nano-meter technology scale is an increasingly a critical work in designing the low power nano-MOSFET circuits. We present a specific compact model for sub-threshold regime leakage current in bulk driven nano-MOSFETs. The proposed logical model is instigated and executed into the latest updated PTM bulk nano-MOSFET model and is found to be in decent accord with technology-CAD simulation data. This paper also reviews various transistor intrinsic leakage mechanisms for nano-MOSFET exclusively in weak inversion, like drain-induced barricade lowering (DIBL), gate-induced drain leakage (GIDL), gate oxide tunneling (GOT) leakage etc. The root cause of the sub-surface leakage current is mainly due to the nano-scale short channel length causing source-drain coupling even in sub-threshold domain. Consequences leading to carriers triumphing the barricade between the source and drain. The enhanced model effectively considers the following parameter dependence in the account for better-quality value-added results like drain-to-source bias (VDS), gate-to-source bias (VGS), channel length (LG), source/drain junction depth (Xj), bulk doping concentration (NBULK), and operating temperature (Top).

  1. Analysis of anastomotic leakage after rectal surgery: A case-control study

    PubMed Central

    Tanaka, Junichiro; Nishikawa, Takeshi; Tanaka, Toshiaki; Kiyomatsu, Tomomichi; Hata, Keisuke; Kawai, Kazushige; Kazama, Shinsuke; Nozawa, Hiroaki; Yamaguchi, Hironori; Ishihara, Soichiro; Sunami, Eiji; Kitayama, Joji; Watanabe, Toshiaki

    2015-01-01

    Background The incidence of anastomotic leakage in rectal surgery is around 10 percent. Poor blood supply to the anastomosis, high anastomotic pressure and tension, increased operative blood loss, long operative time, and male sex are risk factors of anastomotic leakage. In the present study, we examined anastomotic leakage cases in rectal surgery at our institute and tried to ascertain the risk factors. Methods Three hundred fifty-seven consecutive patients who underwent rectal resection with anastomosis between January 2008 and October 2013 were included in the study. Patients were divided into two groups according to the existence of anastomotic leakage. Clinicopathological features, operative procedures, and intraoperative outcomes were compared between the two groups. Regarding intraoperative procedure, we focused on the ligation level of the inferior mesenteric artery, installing a transanal drainage tube in the rectum, and constructing a diverting stoma. Results Anastomotic leakage occurred in eight patients. All of them were male (p = 0.0284). There were no statistical differences in other characteristics of the patients or tumors, in operative procedures, or in intraoperative outcomes. Conclusions In the present study, no statistically significant risk factors for anastomotic leakage in rectal surgery were detected, except for male sex. However, the rate of anastomotic leakage at our institute was revealed to be rather low. Our exertion to preserve good blood flow and to prevent high tension and pressure on the anastomosis in operation may have led to this result. PMID:26042185

  2. In vitro and ex vivo microbial leakage assessment in endodontics: A literature review

    PubMed Central

    Savadkouhi, Sohrab Tour; Bakhtiar, Hengameh; Ardestani, Safoura Emami

    2016-01-01

    The aim of this study was to perform a literature review of published in-vitro and ex-vivo studies, which evaluated microbial leakage in endodontics in the past 10 years. A comprehensive electronic literature search was carried out in PubMed database for English articles published from 2005 to 2016 using the keywords “endodontics,” “in vitro,” “ex vivo,” “microbial leakage,” “microbial penetration,” “saliva,” “Enterococcus faecalis,” “E. faecalis,” “endodontic sealers,” “temporary filling material,” “apical plug,” “mineral trioxide aggregate,” and “MTA.” The keywords were combined using Boolean operators AND/OR. Based on our search strategy, 33 relevant articles were included in the study. There are three main methods for assessment of bacterial microleakage, namely, (A) the dual-chamber leakage model, (B) detection of bacteria using a scanning electron microscope (SEM), and (C) polymerase chain reaction. All bacterial leakage models have some limitations and may yield different results compared to other microleakage evaluation techniques (i.e., dye penetration, fluid filtration, or electrochemical tests). The results of SEM correlated with those of microbial leakage test in most studies. Microbial leakage test using saliva better simulates the clinical setting for assessment of the leakage of single or mixed bacterial species. PMID:28032041

  3. The effect of smear layer on microbial coronal leakage of gutta-percha root fillings.

    PubMed

    Chailertvanitkul, P; Saunders, W P; MacKenzie, D

    1996-07-01

    The aim of this in vitro study was to determine the effect of removal of the smear layer on canal obturation as measured by penetration of bacteria from a coronal direction. One hundred and twenty extracted human teeth with straight, single root canals were decoronated. The canals were prepared using the modified double-flared technique with balanced force under copious irrigation. The apical matrix was prepared to size 40 and apical patency subsequently confirmed with a size 15 file. The teeth were divided randomly into experimental groups (80 teeth) and control groups (40 teeth). The root canals of 40 experimental and 20 control teeth were rinsed with 40% citric acid and 2% NaOCl to remove the smear layer before obturation. In experimental groups, 20 teeth with smear layer intact and 20 teeth with smear layer removed were obturated with lateral condensation of cold gutta-percha and Apexit sealer. A further 20 teeth with smear layer intact and 20 teeth with smear layer removed were obturated with the Trifecta technique with the same sealer. In control groups, 10 teeth with smear layer intact and 10 teeth with smear layer removed were obturated with lateral condensation of cold gutta-percha and Apexit sealer. These teeth were completely sealed both coronally and apically to serve as negative controls. The remaining 20 teeth with either smear layer intact or smear layer removed were not obturated and served as the positive controls. The root surface of each tooth was sealed with nail varnish. The cut end of a polypropylene tube was sealed around the coronal part of each root canal so that bacteria placed therein could move only through the obturated canal space. Each root was placed in a glass bottle containing sterile Todd-Hewitt Broth (THB) and aliquots of 0.5 ml of THB were injected into the polypropylene tube. The model system was centrifuged at 168 g. An innoculum of Streptococcus sanguis in THB was placed in each coronal chamber at 5-day intervals and daily

  4. Hypothesis of demodicidosis rosacea flushing etiopathogenesis.

    PubMed

    Robledo, Mary Ann; Orduz, Mariana

    2015-04-01

    Most of the patients with erythematotelangiectatic rosacea are characterized by flushing, oedema and telangiectasia. The etiopathogenesis of the flushing in rosacea patients is unknown. Clinically the flushing in rosacea is similar to the "Asian flushing syndrome". Most Asians have an overactive alcohol dehydrogenase (ADH) that tends to break down alcohol into acetaldehyde faster. People with "Asians flushing syndrome" have a genetic disorder with the Aldehyde Dehydrogenase 2(∗)2 (ALDH2(∗)2) allele. This is the reason why they do not metabolize very well the acetaldehyde that comes from the alcohol, which means that acetaldehyde takes much longer to clear from their blood. ALDH2 enzyme is primarily responsible for oxidation of acetaldehyde derived from ethanol metabolism, as well as oxidation of various other endogenous and exogenous aldehydes. Acetaldehyde produces the vasodilatation in the "Asian flushing syndrome". The antibodies against the GroEl chaperonin protein, a 62-kDa heat shock protein were found in the Bacillus oleronius isolated from Demodex mites, in rosacea patients. The GroEl chaperonin protein is a protein that plays a key role in normal folding of ALDH2. If the GroEl chaperonin antibodies found in patients with rosacea, cross react with the human GroEl chaperonin protein, they will not fold normally the ALDH2, and then the enzyme will not metabolize the acetaldehyde. Many of the patients with rosacea have a concomitant infection with Helicobacter pylori in their stomach. The H.pylori produces high amounts of acetaldehyde, which comes from their metabolism of ethanol or carbohydrates. As a result, high amounts of acetaldehyde will circulate for longer time in the blood, until the liver CYP2E1(p450) enzyme system finally metabilizes the acetaldehyde, during that period of time the patients will experience a flushing as well as the people with the "Asian flushing syndrome" suffer when they drink ethanol. To prove the hypothesis it is necessary

  5. Reflections on Hypothesis Testing in Response to Ulrich.

    ERIC Educational Resources Information Center

    Zarefsky, David

    1984-01-01

    Responds that hypothesis testing is not a formula for judging debates but an attempt to model the nature of argumentation itself. Addresses criticisms of hypothesis testing and the role of paradigms in argumentation theory and practice. (PD)

  6. Mars' Oceanus Borealis, Ancient Glaciers, and the MEGAOUTFLO Hypothesis

    NASA Technical Reports Server (NTRS)

    Baker, V. R.; Strom, R. G.; Dohm, J. M.; Gulick, V. C.; Kargel, J. S.; Komatsu, G.; Ori, G. G.; Rice, J. W., Jr.

    2000-01-01

    Recent results from Global Surveyor corroborate the hypothesis that episodes of outburst flooding produced ponded water and climate change on Mars. This hypothesis colligates diverse facts concerning the Martian landscape and its history into a unified genetic system.

  7. Hypothesis Generation: A Final Report of Three Years of Research

    DTIC Science & Technology

    1980-03-03

    This project was devoted to a study of hypothesis generation. Hypothesis generation is the process by which the decision maker specifies possible hypotheses, or states of the world , that are relevant in a decision problem.

  8. A retrospective analysis of endoscopic treatment outcomes in patients with postoperative bile leakage

    PubMed Central

    Sayar, Suleyman; Olmez, Sehmus; Avcioglu, Ufuk; Tenlik, Ilyas; Saritas, Bunyamin; Ozdil, Kamil; Altiparmak, Emin; Ozaslan, Ersan

    2016-01-01

    OBJECTIVE: Bile leakage, while rare, can be a complication seen after cholecystectomy. It may also occur after hepatic or biliary surgical procedures. Etiology may be underlying pathology or surgical complication. Endoscopic retrograde cholangiopancreatography (ERCP) can play major role in diagnosis and treatment of bile leakage. Present study was a retrospective analysis of outcomes of ERCP procedure in patients with bile leakage. METHODS: Patients who underwent ERCP for bile leakage after surgery between 2008 and 2012 were included in the study. Etiology, clinical and radiological characteristics, and endoscopic treatment outcomes were recorded and analyzed. RESULTS: Total of 31 patients (10 male, 21 female) were included in the study. ERCP was performed for bile leakage after cholecystectomy in 20 patients, after hydatid cyst operation in 10 patients, and after hepatic resection in 1 patient. Clinical signs and symptoms of bile leakage included abdominal pain, bile drainage from percutaneous drain, peritonitis, jaundice, and bilioma. Twelve (60%) patients were treated with endoscopic sphincterotomy (ES) and nasobiliary drainage (NBD) catheter, 7 patients (35%) were treated with ES and biliary stent (BS), and 1 patient (5%) was treated with ES alone. Treatment efficiency was 100% in bile leakage cases after cholecystectomy. Ten (32%) cases of hydatid cyst surgery had subsequent cystobiliary fistula. Of these patients, 7 were treated with ES and NBD, 2 were treated with ES and BS, and 1 patient (8%) with ES alone. Treatment was successful in 90% of these cases. CONCLUSION: ERCP is an effective method to diagnose and treat bile leakage. Endoscopic treatment of postoperative bile leakage should be individualized based on etiological and other factors, such as accompanying fistula. PMID:28058396

  9. Aminoacylating Urzymes Challenge the RNA World Hypothesis*♦

    PubMed Central

    Li, Li; Francklyn, Christopher; Carter, Charles W.

    2013-01-01

    We describe experimental evidence that ancestral peptide catalysts substantially accelerated development of genetic coding. Structurally invariant 120–130-residue Urzymes (Ur = primitive plus enzyme) derived from Class I and Class II aminoacyl-tRNA synthetases (aaRSs) acylate tRNA far faster than the uncatalyzed rate of nonribosomal peptide bond formation from activated amino acids. These new data allow us to demonstrate statistically indistinguishable catalytic profiles for Class I and II aaRSs in both amino acid activation and tRNA acylation, over a time period extending to well before the assembly of full-length enzymes and even further before the Last Universal Common Ancestor. Both Urzymes also exhibit ∼60% of the contemporary catalytic proficiencies. Moreover, they are linked by ancestral sense/antisense genetic coding, and their evident modularities suggest descent from even simpler ancestral pairs also coded by opposite strands of the same gene. Thus, aaRS Urzymes substantially pre-date modern aaRS but are, nevertheless, highly evolved. Their unexpectedly advanced catalytic repertoires, sense/antisense coding, and ancestral modularities imply considerable prior protein-tRNA co-evolution. Further, unlike ribozymes that motivated the RNA World hypothesis, Class I and II Urzyme·tRNA pairs represent consensus ancestral forms sufficient for codon-directed synthesis of nonrandom peptides. By tracing aaRS catalytic activities back to simpler ancestral peptides, we demonstrate key steps for a simpler and hence more probable peptide·RNA development of rapid coding systems matching amino acids with anticodon trinucleotides. PMID:23867455

  10. Mechanism of drug-induced gingival overgrowth revisited: a unifying hypothesis

    PubMed Central

    Brown, RS; Arany, PR

    2015-01-01

    Drug-induced gingival overgrowth (DIGO) is a disfiguring side effect of anti-convulsants, calcineurin inhibitors, and calcium channel blocking agents. A unifying hypothesis has been constructed which begins with cation flux inhibition induced by all three of these drug categories. Decreased cation influx of folic acid active transport within gingival fibroblasts leads to decreased cellular folate uptake, which in turn leads to changes in matrix metalloproteinases metabolism and the failure to activate collagenase. Decreased availability of activated collagenase results in decreased degradation of accumulated connective tissue which presents as DIGO. Studies supporting this hypothesis are discussed. PMID:24893951

  11. Investigation of Gate Leakage Current in Nitrogen-Irradiated Al(x)Ga(1-x)N/GaN Heterostructures

    DTIC Science & Technology

    2011-03-01

    5 C. Leakage models for the heterojunction bipolar transistor ...acceptor defects— compensating for donors [2]. 7 C. Leakage models for the heterojunction bipolar transistor Gray [2] proposed 3 primary current...paths for gate leakage in heterojunction bipolar transistors (HBTs) as shown in Figure 2: 1. Lateral surface current, possibly due to conductive

  12. Mefloquine use, psychosis, and violence: A retinoid toxicity hypothesis

    PubMed Central

    Mawson, Anthony R.

    2013-01-01

    Mefloquine use has been linked to severe gastrointestinal and neuropsychiatric adverse effects, including cognitive disturbances, anxiety, depression, psychosis, and violence. The adverse effects of the drug are thought to result from the secondary consequences of hepatocellular injury; in fact, mefloquine is known to cause a transient, anicteric chemical hepatitis. However, the mechanism of mefloquine-associated liver damage and the associated neuropsychiatric and behavioral effects of the drug are not well understood. Mefloquine and other 8-amino-quinolines are the only antimalarial drugs that target the liver-stage malaria parasites, which selectively absorb vitamin A from the host. Vitamin A is also stored mainly in the liver, in potentially poisonous concentrations. These observations suggest that both the therapeutic effectiveness of mefloquine and its adverse effects are related to the ability of the 8-aminoquinolines to alter the metabolism of retinoids (vitamin A and its congeners). Several lines of evidence support the hypothesis that mefloquine neurotoxicity and other adverse effects reflect an endogenous form of hypervitaminosis A due to a process involving: mefloquine-induced dehydrogenase inhibition; the accumulation of retinoids in the liver; retinoid-induced hepatocellular damage; the spillage of stored retinoids into the circulation; and the transport of these compounds to the gut and brain in toxic concentrations. The retinoid hypothesis could be tested clinically by comparing cases of mefloquine toxicity and untreated controls in terms of retinoid profiles (retinol, retinyl esters, percent retinyl esters, and retinoic acid). Subject to such tests, retinoid profiling could provide an indicator for assessing mefloquine-associated adverse effects. PMID:23852388

  13. Mefloquine use, psychosis, and violence: a retinoid toxicity hypothesis.

    PubMed

    Mawson, Anthony

    2013-07-15

    Mefloquine use has been linked to severe gastrointestinal and neuropsychiatric adverse effects, including cognitive disturbances, anxiety, depression, psychosis, and violence. The adverse effects of the drug are thought to result from the secondary consequences of hepatocellular injury; in fact, mefloquine is known to cause a transient, anicteric chemical hepatitis. However, the mechanism of mefloquine-associated liver damage and the associated neuropsychiatric and behavioral effects of the drug are not well understood. Mefloquine and other 8-amino-quinolines are the only antimalarial drugs that target the liver-stage malaria parasites, which selectively absorb vitamin A from the host. Vitamin A is also stored mainly in the liver, in potentially poisonous concentrations. These observations suggest that both the therapeutic effectiveness of mefloquine and its adverse effects are related to the ability of the 8-aminoquinolines to alter the metabolism of retinoids (vitamin A and its congeners). Several lines of evidence support the hypothesis that mefloquine neurotoxicity and other adverse effects reflect an endogenous form of hypervitaminosis A due to a process involving: mefloquine-induced dehydrogenase inhibition; the accumulation of retinoids in the liver; retinoid-induced hepatocellular damage; the spillage of stored retinoids into the circulation; and the transport of these compounds to the gut and brain in toxic concentrations. The retinoid hypothesis could be tested clinically by comparing cases of mefloquine toxicity and untreated controls in terms of retinoid profiles (retinol, retinyl esters, percent retinyl esters, and retinoic acid). Subject to such tests, retinoid profiling could provide an indicator for assessing mefloquine-associated adverse effects.

  14. Urban leakage of liquefied petroleum gas and its impact on Mexico City air quality

    SciTech Connect

    Blake, D.R.; Rowland, F.S.

    1995-08-18

    Alkane hydrocarbons (propane, isobutane, and n-butane) from liquefied petroleum gas (LPG) are present in major quantities throughout Mexico City air because of leakage of the unburned gas from numerous urban sources. These hydrocarbons, together with olefinic minor LPG components, furnish substantial amounts of hydroxyl radical reactivity, a major precursor to formation of the ozone component of urban smog. The combined processes of unburned leakage and incomplete combustion of LPG play significant role in causing the excessive ozone characteristic of Mexico City. Reductions in ozone levels should be possible through changes in LPG composition and lowered rates of leakage. 23 refs., 3 tabs.

  15. Efficient quantum dialogue using entangled states and entanglement swapping without information leakage

    NASA Astrophysics Data System (ADS)

    Wang, He; Zhang, Yu Qing; Liu, Xue Feng; Hu, Yu Pu

    2016-06-01

    We propose a novel quantum dialogue protocol by using the generalized Bell states and entanglement swapping. In the protocol, a sequence of ordered two-qutrit entangled states acts as quantum information channel for exchanging secret messages directly and simultaneously. Besides, a secret key string is shared between the communicants to overcome information leakage. Different from those previous information leakage-resistant quantum dialogue protocols, the particles, composed of one of each pair of entangled states, are transmitted only one time in the proposed protocol. Security analysis shows that our protocol can overcome information leakage and resist several well-known attacks. Moreover, the efficiency of our scheme is acceptable.

  16. Detecting and Reducing Gate Leakage in Superconducting Qubits using Randomized Benchmarking

    NASA Astrophysics Data System (ADS)

    Chen, Z.; Kelly, J.; Barends, R.; Campbell, B.; Chen, Y.; Chiaro, B.; Dunsworth, A.; Fowler, A.; Hoi, I.-C.; Jeffrey, E.; Megrant, A.; Mutus, J.; Neill, C.; O'Malley, P. J. J.; Quintana, C.; Roushan, P.; Sank, D.; Vainsencher, A.; Wenner, J.; White, T.; Korotkov, A. N.; Cleland, A. N.; Martinis, J. M.

    2015-03-01

    Superconducting qubits are a promising platform for building a quantum computer due to their scalability and ease of control. One potential drawback is the existence of more than two energy levels, which can allow the qubit to leak out of the computational subspace when performing operations. This leakage error is particularly detrimental in the surface code scheme, where it leads to correlated errors. I will present a method for characterizing gate leakage rates using randomized benchmarking, and present strategies based on these results for reducing leakage.

  17. Leakage of K+ ions from Staphylococcus aureus in response to tea tree oil.

    PubMed

    Hada, Toshiko; Inoue, Yoshihiro; Shiraishi, Akiko; Hamashima, Hajime

    2003-06-01

    The leakage of K(+) ions from Staphylococcus aureus in response to tea tree oil (TTO) was investigated with an ion-selective electrode. The amount of leaked K(+) ions and the rate of leakage of K(+) ions induced by TTO were dependent on the concentration of TTO. Measurements of initial rates required less time than measurements of total amounts and provided an index of the interaction between TTO and the cell membrane. Thus, the initial rate of leakage might be a more useful measure of the antibacterial activity of TTO than the total amount.

  18. Range of validity of the Rayleigh hypothesis.

    PubMed

    Watanabe, T; Choyal, Y; Minami, K; Granatstein, V L

    2004-05-01

    The parameter range over which the Rayleigh hypothesis (RH) for optical gratings might be validly applied to analysis of high power backward wave oscillators has been investigated numerically. It had been pointed out that from a rigorous mathematical viewpoint, RH was only valid for a shallow corrugation of slow wave structure (SWS) such that h K0 <0.448; here, h and K0 are, respectively, the amplitude and wave number of the periodicity in a sinusoidal planar grating. We numerically analyze the electromagnetic fields in the axisymmetric SWS with and without use of RH. The field patterns and eigenfrequency for the SWS are solved numerically for a given k(z) by using the code HIDM (higher order implicit difference method) that is free from the RH. It is found that, for a deep corrugation, h K0 =5 x 0.448, using RH is still valid for obtaining the dispersion relation, although the Floquet harmonic expansion (FHE) fails to correctly represent the field patterns inside the corrugation. Accordingly, there exists a discrepancy between the validity of using RH for obtaining dispersion relations and for an exact convergence of FHE everywhere in the SWS.

  19. Confabulation: Developing the 'emotion dysregulation' hypothesis.

    PubMed

    Turnbull, Oliver H; Salas, Christian E

    2017-02-01

    Confabulations offer unique opportunities for establishing the neurobiological basis of delusional thinking. As regards causal factors, a review of the confabulation literature suggests that neither amnesia nor executive impairment can be the sole (or perhaps even the primary) cause of all delusional beliefs - though they may act in concert with other factors. A key perspective in the modern literature is that many delusions have an emotionally positive or 'wishful' element, that may serve to modulate or manage emotional experience. Some authors have referred to this perspective as the 'emotion dysregulation' hypothesis. In this article we review the theoretical underpinnings of this approach, and develop the idea by suggesting that the positive aspects of confabulatory states may have a role in perpetuating the imbalance between cognitive control and emotion. We draw on existing evidence from fields outside neuropsychology, to argue for three main causal factors: that positive emotions are related to more global or schematic forms of cognitive processing; that positive emotions influence the accuracy of memory recollection; and that positive emotions make people more susceptible to false memories. These findings suggest that the emotions that we want to feel (or do not want to feel) can influence the way we reconstruct past experiences and generate a sense of self - a proposition that bears on a unified theory of delusional belief states.

  20. The Hutson hypothesis. A clinical study.

    PubMed

    Scott, J E

    1987-07-01

    The hypothesis that testicular descent may be governed by Müllerian inhibiting substance (MIS) was investigated by observing the position of the testes in 13 children with XY karyotype and persistent Müllerian duct syndrome (PMDS). It was found that there was a direct relationship between failure of testicular descent and the degree of development of the Müllerian system. Where the Müllerian system was complete, the testes were in an ovarian position but where only the vagina was present, the testes were sometimes found in the inguinal region. To discover whether excessive androgen activity in females might produce ovarian descent, the position of the ovaries in 15 children with severe adrenogenital syndrome was observed. Despite complete genital masculinisation in three children and almost complete in six, all but one ovary was in the normal position: that ovary had descended in an inguinal hernia sac. These findings suggest that MIS rather than androgens may be responsible for the first or abdominal phase of testicular descent. Even excessive androgen activity failed to cause ovarian descent.