Induction Hypothesis Research Articles

Numerical method for nonlinear two-phase displacement problem and its application

For the three-dimensional nonlinear two-phase displacement problem, the modified upwind finite difference fractional steps schemes were put forward. Some techniques, such as calculus of variations, induction hypothesis, decomposition of high order difference operators, the theory of prior estimates and techniques were used. Optimal order estimates were derived for the error in the approximation solution. These methods have been successfully used to predict the consequences of seawater intrusion and protection projects.

Value network dynamics in 3G–4G wireless communications: A systems thinking approach to strategic value assessment

This article develops a map to analyze the dynamic forces that influence the structure and development of 3G (third generation) wireless communications value networks. The analysis builds on the Strategic Value Assessment Model (Fine, et al. [Fine, Charles H., Vardan, Roger, Pethick, Robert, El Hout, Jamal. Rapid-Response Capability in value chain Design. MIT Sloan Manage Rev 2002, 43(Winter): 69–75.]) and utilizes a qualitative System Dynamics mapping approach. The map focuses on the driving forces affecting user adoption of 3G services, focusing on customer dynamics, competitive dynamics, and technology dynamics. To analyze adoption of 3G services by customers, the articles maps the dynamics of (1) network investment and user population, (2) entry of service innovators as well as price competitors, (3) the effects of positive network externalities arising from a larger user population, (4) price compression as lower willingness-to-pay users adopt 3G services, (5) scale economies in terminal costs and prices, and (6) new content development as a draw to new users. Applying inductive systems diagrams hypotheses are integrated into a causal loop map and tested with data collected at 15 communications-industry workshops attended by 190 participants in Europe. The map aims to deepen the understanding of the possible evolutionary paths of the 3G wireless value network. The article seeks also to assess which future scenarios are plausible and what dynamic triggers might make them likely.

The Tasman Project Of Seafloor Magnetotelluric Exploration

Author(s): Ferguson, Ian James | Abstract: The Tasman Project of Seafloor Magnetotelluric Exploration was performed between December 1983 and April 1984 in order to investigate the electrical conductivity structure beneath the Tasman Seafloor and the Australian continental margin. Recordings were made at nine seafloor and nine land sites on a line extending from inland Australia to the Lord Howe Rise in the eastern Tasman Sea. Magnetic field recordings were made at all sites and horizontal electric field recordings at seven of the seafloor sites. In addition, oceanographic recordings were made at several of the seafloor sites, as an additional aim of the project was to provide physical oceanographic information on the Tasman Sea. Data return from the experiment was almost complete and the data quality high. All of the raw recordings have been converted into final magnetic horizontal electric field and ­oceanographic time series.An analysis of the seafloor magnetotelluric (SFMT) data has been completed. The 'results indicate that geomagnetic induction in the Tasman Sea is a three-dimensional process dependent on the large-scale shape of the Tasman Sea. The seafloor impedances have a dominantly two-dimensional form with the B-pol impedance component (the component perpendicular to the trend of the Tasman Sea) being strongly attenuated near the Australian coastline. Evidence for the three-dimensionality includes large impedance skew-angles and consistent differences between impedances estimated using the SFMT and vertical gradient sounding (VGS) methods. The spatial consistency of these results supports the hypothesis of large-scale geomagnetic induction in the Tasman Sea. The induction arrows calculated for land and seafloor sites near the Australian coast exhibit significant components parallel to the coastline, providing further evidence for a three-­dimensional process.Evidence suggests that the most appropriate data to analyse using one-dimensional MT techniques are the E-pol impedances from three sites, TP3, TP4 and TP5, in the central Tasman Sea. Inversions were therefore performed on these data using delta-function and minimum-structure inversion algorithms. Delta function inversions were performed in order to investigate the one-dimensionality of the data, the depth of resolution of the and the significance of differences between the conductivity models at the different sites. Minimum-structure inversions were performed in order to produce more physically-realistic conductivity profiles, and to examine which features in the profile are definitely required by the data. In addition to these inversions, the B-pol impedance terms from the seafloor sites were used with the MT anisotropy method to determine the minimum integrated crustal resistance of the Tasman Seafloor, 107 [capital omega].m2. The E-pol impedance terms were used to estimate the depth to the good conductor beneath each site with the MT asymptotic method.The conductivity models obtained for sites TP3 and TP4 appear to a reliable conductivity profile for the Tasman Sea. The Tasman Sea profile includes a high conducting layer occurring at a depth comparable to that for similar age lithosphere in the Pacific Ocean. The differences between the SFMT and VGS impedance estimates cause some ambiguity regarding the depth to the high conducting layer with the VGS and SFMT impedances estimates suggesting depths of 100 and 200 km respectively. Comparison of the conductivity models with other geophysical results suggests the correct depth lies between 120 and 150 km. At shallow depths the TP4 profile is more conductive than the TP3 profile. The higher conductance at TP4 cannot be explained by differences between the sediment layer at the two sites and is tentatively attributed to thermal effects associated with the source of an active seamount chain located near TP4.The conductivity profile obtained for the third site, TP5, in the Central Tasman is probably only geophysically accurate at depths greater than 200 km. The deep structure at this site is more resistive than at sites TP4 and TP3 to the east, a result supported by the asymptotic-method results for sites near TP5. Confirmation of the conductivity results for the Tasman Sea will be provided by the application of three-dimensional modelling methods. In particular, thin-sheet modelling should indicate the accuracy of the assumptions made during the ID analyses described in this thesis.In addition to information on the sub-oceanic conductivity structure, the Tasman Project has provided valuable information in other areas. Induction arrows at the land and seafloor sites are currently being analysed for information on the electrical conductivity structure of the Australian continental margin. Physical oceanographic information on processes including tides, eddies, and internal waves has been obtained, and information is also available on geomagnetic source-fields in the Tasman Sea region.

Tunnel Propagation of Postshock Activations as a Hypothesis for Fibrillation Induction and Isoelectric Window

Comprehensive understanding of the ventricular response to shocks is the approach most likely to succeed in reducing defibrillation threshold. We propose a new theory of shock-induced arrhythmogenesis that unifies all known aspects of the response of the heart to monophasic (MS) and biphasic (BS) shocks. The central hypothesis is that submerged "tunnel" propagation of postshock activations through shock-induced intramural excitable areas underlies fibrillation induction and the existence of isoelectric window. We conducted simulations of fibrillation induction using a realistic bidomain model of rabbit ventricles. Following pacing, MS and BS of various strengths/timings were delivered. The results demonstrated that, during the isoelectric window, an activation originated deep within the ventricular wall, arising from virtual electrodes; it then propagated fully intramurally through an excitable tunnel induced by the shock, until it emerged onto the epicardium, becoming the earliest-propagated postshock activation. Differences in shock outcomes for MS and BS were found to stem from the narrower BS intramural postshock excitable area, often resulting in conduction block, and the difference in the mechanisms of origin of the postshock activations, namely intramural virtual electrode-induced phase singularity for MS and virtual electrode-induced propagated graded response for BS. This study provides a novel analysis of the 3D mechanisms underlying the origin of postshock activations in the process of fibrillation induction by MS and BS and the existence of isoelectric window. The tunnel propagation hypothesis could open a new avenue for interventions exploration to achieve significantly lower defibrillation threshold.

Effects of Azithromycin on the Expression of ATP Binding Cassette Transporters in Epithelial Cells from the Airways of Cystic Fibrosis Patients

Induction of ATP Binding Cassette (ABC) proteins involved in chloride transport has been proposed as a possible mechanism of the beneficial effects of azithromycin (AZM) in cystic fibrosis (CF) patients. This study focused on the effects of AZM on mRNA and protein expression of Multidrug Resistance-associated Protein 1 (MRP1) and Multidrug Resistance Protein 1 (MDR1) by real-time quantitative PCR, flow cytometry and gene reporter assays in two CF and two isogenic non-CF airway epithelial cell lines. We detected higher levels of MRP1 and lower levels of MDR1 mRNA in CF versus non-CF cells while both proteins were not differentially expressed. After AZM treatment we found modest differences in MRP1 and MDR1 mRNA expression while protein levels were unaffected. The ability of AZM to regulate MRP1 promoter transcriptional activity was excluded by gene reporter assays. Our data do not support the hypothesis of induction of ABC transporters by AZM.

Experience-Induced Changes in Sugar Taste Discrimination

An apparent plasticity in glucose sensitivity was first noted while studying human taste variants, but the experimental design did not rule out regression to the mean. Since then, a human taste induction hypothesis that sensitivity for a taste stimulus increases with repeated exposure to it has been supported first by experience-induced changes in taste identification of monosodium glutamate and, subsequently, in sensory detection of glutaraldehyde, as well as in psychophysical and functional magnetic resonance imaging responses to novel taste stimuli. Yet, whether such plasticity occurs for the highly familiar taste of sugar remained unconfirmed. Therefore, we tested the taste induction hypothesis for sugar using a counterbalanced design, consisting of 3 pretreatment and 2 treatment conditions. The effects over time also were followed with an additional group of participants. The results showed that 1) experience with fructose significantly increases sensitivity for the taste of a sugar, glucose; 2) there are no significant differences in the sugar sensitivity between groups of randomly assigned participants before treatments; 3) a single session of 5 brief tastings of glucose has an effect on glucose sensitivity when tested 11 or 12 days later; and 4) without continued treatment, the increased sensitivity reverses within 33 or 34 days.

An approach to automatic deductive synthesis of functional programs

The work deals with automatic deductive synthesis of functional programs. Formal specification of a program is taken as a mathematical existence theorem and while proving it, we derive a program and simultaneously prove that this program corresponds to given specification. Several problems have to be resolved for automatic synthesis: the choice of synthesis rules that allows us to derive the basic constructions of a functional program, order of rule application and choice of a particular induction rule. The method proposed here is based on the deductive tableau method. The basic method gives rules for functional program construction. To determine the proof strategy we use some external heuristics, including rippling. And for the induction hypothesis formation the combination of rippling and the deductive tableau method became very useful. The proposed techniques are implemented in the system ALISA (Automatic Lisp Synthesizer) and used for automatic synthesis of several functions in the Lisp language.

A Social Deafferentation Hypothesis for Induction of Active Schizophrenia

The "social brain" of humans reflects widespread neural resources dedicated to understanding the conversational language, emotionality, states of mind, and intentions of other persons. A social deafferentation (SDA) hypothesis for induction of active schizophrenia is proposed. Analogous to hallucinations produced by sensory deafferentation, such as phantom limb, the SDA hypothesis assumes that high levels of social withdrawal/isolation in vulnerable individuals prompt social cognition programs to produce spurious social meaning in the form of complex, emotionally compelling hallucinations and delusions representing other persons or agents. Arguments against the SDA hypothesis are discussed, and predictions deriving from the hypothesis are offered.

Positive sharp wave origin: Evidence supporting the electrode initiation hypothesis

This investigation analyzes the temporal characteristics of maximal depolarization times for three waveforms: end-plate spikes, fibrillation potentials, and positive sharp waves (PSWs) to provide support for the electrode initiation hypothesis of PSW induction. The maximal depolarization times for PSWs are documented to comprise two distinct populations conforming to relatively short and comparatively longer maximal depolarization times. Those PSWs with short maximal depolarization times were found to be equivalent to end-plate spike maximal depolarization times, whereas those with longer times were comparable to fibrillation potentials. The PSW group with shorter maximal depolarization times was encountered more frequently. The combination of two distinct groups of PSWs with respective times comparable to end-plate spikes and fibrillation potentials supports the hypothesis that the majority of PSWs originate at the recording electrode during insertion, whereas a smaller population of PSWs arises as propagating fibrillation potentials that block at the recording electrode. Subcutaneous compared to intramuscular recordings from denervated muscle document that the recording electrode is necessary to both record and produce PSWs. Hence, this study confirms the proposed hypothesis that the majority of observed PSWs represent a suprathreshold single muscle-fiber discharge induced by, and originating in close proximity to, a perielectrode crushed membrane that then propagate away from the electrode; a smaller population of PSWs conform to that of a blocked fibrillation potential.

Deaccumulation techniques for improving provability

Several induction theorem provers were developed to verify functional programs mechanically. Unfortunately, automatic verification often fails for functions with accumulating arguments. Using concepts from the theory of tree transducers and extending on earlier work, the paper develops automatic transformations from accumulative functional programs into non-accumulative ones, which are much better suited for mechanized verification. The overall goal is to reduce the need for generalizing induction hypotheses in (semi-)automatic provers. Via the correspondence between imperative programs and tail-recursive functions, the presented approach can also help to reduce the need for inventing loop invariants in the verification of imperative programs.

Consequences of Mediterranean warming events in seagrass (Posidonia oceanica) flowering records

Abstract Posidonia oceanica, a seagrass endemic to the Mediterranean forms extended and extremely persistent meadows. It is a clonal plant with an apparently irregular pattern of flowering events. An extensive bibliographic review allowed the reconstruction of past flowering events of this species around the Mediterranean, with a high degree of confidence for the last 30 years. The data series on annual flowering prevalence (FP, flowering records per total records) and flowering intensity (FI, fraction of flowering shoots) produced have been compared with four series on Sea Surface annual Temperature maxima (SSTmax) obtained for the NW Mediterranean (averaged from the local data series of l'Estartit and Villefranche: 1957–2005) and for the Eastern, Western basin and the whole Mediterranean sea (extracted from NCEP Reynolds interpolated SST maps: 1982–2005). Significant warming trends are detected in the Mediterranean SSTmax series, at a rate of (mean+SE) 0.04±0.01°C yr−1 (R2=0.24, P<0.01, N=24 years), in the Eastern basin series (0.06±0.01°C yr−1, R2=0.43, P<0.001, N=24 years) and in the long SSTmax series of the NW Mediterranean (0.02±0.01 C yr−1, R2=0.12, P<0.02, N=49 years). The magnitudes of the SSTmax anomalies around the absolute warming trend do not increase with time in any SSTmax series. Peaks of FP and FI in the Mediterranean seem to occur each 9–11 years, and coincide with peaks of annual SSTmax. Annual FP and FI increase with the residuals of annual SSTmax warming trend in all Mediterranean basins (FPMED: R2=0.27, P<0.01, N=23; FPNW: R2=0.34, P<0.01, N=31; FPE: R2=0.20; P<0.10, N=23). An outstanding event of P. oceanica flowering across the Mediterranean has been registered in Autumn 2003; 1 month after the highest annual SSTmax recorded in the series. The hypothesis of flowering induction by thermal stress as the possible cause of this relationship is discussed, as well as the potential use of P. oceanica flowering record as early indicator of biological change induced by global sea warming in Mediterranean marine ecosystems.

Modeling the regulation of the competence-evoking quorum sensing network in Streptococcus pneumoniae

Competence for genetic transformation seems to play a fundamental role in the biology of Streptococcus pneumoniae and is believed to account for serotype switching, evolution of virulence factors, and rapid emergence of antibiotic resistance. The initiation of competence is regulated by the quorum sensing system referred as the ComABCDE pathway. Experimental studies reveal that competence is down-regulated a short time after its induction and several hypotheses about the mechanism(s) responsible for this shut-down have been presented. Possibly, a ComX-dependent gene product, such as a repressor or a phosphatase, is involved. To better understand the down-regulation of the competence-evoking system in S. pneumoniae, a mathematical model was set up. By analyzing the model, we suggest that shut-down of competence possibly occurs at the transcriptional level on the comCDE operon. As a result of introducing a putative comX-dependent repressor, which inhibits expression of comCDE and comX, in the mathematical model, competence is demonstrated to appear in waves. This is supported by experimental studies showing the appearance of successive competence cycles in pneumococcal batch cultures.

Study of Current Distribution in ITER TFMC NbTi Busbar III

In the framework of the development of High Temperature Superconducting current leads (HTSCL), one demonstrator was tested at Forschungszentrum Karlsruhe (FZK) in 2004 together with a conventional current lead. Both were connected by a superconducting short circuit NbTi conductor, referred as busbar III (BBIII). Here the BBIII was used for current distribution measurements. In addition to a 64 Hall Probe (HP) system, two additional 4-HP heads from CEA were assembled at both ends of the BBIII. This system, already successfully used during the TFMC test phase II, was now adapted by FZK to the present BBIII set-up. Electrical tests were performed for conductor currents up to 80 kA without background magnetic field. In this paper, the analysis of the current distribution is presented using two methods: (1) The current barycenter excursion was investigated in various runs. A comparative study is presented between resistive and inductive hypotheses where the current is supposed to be uniformly distributed. In particular, we show that the two hypotheses lead to different results. (2) A global model of the current bundles distribution between four artificial subcables is investigated. More quantitative results show current imbalances between subcables to be either significant or weak, depending on whether the resistive or the inductive hypothesis is considered. A discussion on why the second solution is thought to be more likely is presented. In addition, a global comparison with results previously obtained during the TFMC tests will be shown

Coloring Graphs with Few Odd Cycles: 11086

Solution by Richard Stong, Rice University, Houston, TX. We prove by induction on the number of vertices that if no vertex of G lies on (?J) odd cycles, then G has a proper /c-coloring (that is, x (G) < k). The claim is trivial with at most k vertices. For a vertex v of G the induction hypothesis yields a proper /c-coloring of G ? v. Since there are (??) pairs of colors and at most (*) ? 1 odd cycles through v, there is a pair of colors, say red and blue, such that no odd cycle through v joins v to both a red neighbor and a blue neighbor. Let G' be the subgraph of G ? v induced by the red and blue vertices. If any component of G' contains both a red neighbor and a blue neighbor of v, then adding v to the path connecting them in G' forms an odd cycle in G joining v to red and blue neighbors, contradicting our choice of colors. Therefore, switching red and blue in each component of G' containing a red neighbor of v removes red from the neighborhood of v. Now coloring v red extends the proper ^-coloring to G.

In memoriam Lauri Saxen (1927-2005)

Dr. Lauri "Tupu" Saxen died last October (2005) at the age of 78. He was a physician, a scientist, a photographer, a naturalist, a great story-teller and a man who enjoyed science enormously. His name has become synonymous with the Finnish school of Developmental Biology, a school that focuses on reciprocal inductive interactions during vertebrate organogenesis. But many biologists probably don't know the full extent of his importance to the field. A few years ago, I had the occasion to outline some of his contributions which are so varied and important that it is difficult to believe that they are the work of one person, and I have included them in this brief eulogy. One could divide his scientific contributions into five categories: (1) the threshold hypothesis of amphibian metamorphosis; (2) the double-gradient hypothesis of primary embryonic induction; (3) the analysis of reciprocal induction during kidney development; (4) the integration of developmental biology with epidemiology and (5) the maintenance of a national infrastructure for science.

How Scientists Confirm Universal Propositions (Laws of Nature).

Scientists regard their inductive hypotheses as confirmed when consistence exists between two or more results obtained by differing methods. Three hierarchical levels of confirmation are applied (I: No counterinstances, II: Several “sieves” described in extenso, III: The network of our entire knowledge into which the hypothesis must fit). Certainty is obtained by the deductive element of the third level. The question of uniformity o i nature is less decisive than the question whether or not the complexity of the processes observed or the limited scope of our senses and instruments permits to see through the causal connections involved.

No Association of INS‐VNTR Genotype and IAA Autoantibodies

Type 1 diabetes is associated with autoimmune responses against insulin, with insulin autoantibodies (IAA) being a hallmark of the disease. Genetic susceptibility to type 1 diabetes is polygenic and includes the INS VNTR-IDDM2 locus, which has been shown to regulate the expression of insulin in the pancreas and thymus. In order to determine whether insulin autoimmunity could be attributed to a genetic susceptibility conferred by the INS-VNTR (IDDM2) locus, we studied the frequency of INS-VNTR alleles and the presence of IAA in 90 patients with new-onset type 1 diabetes. IAA were detected in 49 of 67 class I/I individuals and 19 of 23 class III/X patients, indicating that there is no association between the INS VNTR-IDDM2-susceptible allele and humoral autoimmunity against insulin. This finding does not support the hypothesis of an allele-specific tolerance induction that could determine susceptibility toward autoimmunity against the insulin protein and subsequently the development of type 1 diabetes.

A randomized placebo-controlled phase II study with the cancer vaccine IGN101 in patients with epithelial solid organ tumors (IGN101/2–01)

2619 Background: IGN101 is a vaccine for therapeutic vaccination against cancers of epithelial origin. The immunogenic principle is the murine monoclonal antibody 17–1A.. The vaccine consists of 0.5 mg alum-adsorbed antibody for s.c. injection.. The antibody carries epitopes that structurally mimic epitopes of the pan-carcinoma glycoprotein EpCAM, and also binds to EpCAM. Repeated vaccinations induce antibodies against EpCAM which may lead to destruction of EpCAM+ tumor cells via activation of natural effector functions. The immunological hypothesis of induction of anti-EpCAM antibodies has been substantiated in phase I studies. Methods: IGN101/2–01 is a 1:1 randomized, blinded, placebo-controlled phase II trial with overall survival as primary endpoint. Secondary endpoints include safety, tolerability and immunogenicity. 240 patients with epithelial cancers stage III or IV, mainly colorectal cancer but also upper GI tract cancer or NSCLC have been recruited between Sept. 2001 and July 2003. Vaccinations with IGN101 or placebo are administered on days 1, 15, 29 and 57 followed by booster injections in weeks 16, 24, 32, 40 and 68. Serum samples are collected at days 1 and 57, in week 16, 32 and 52 and every 4 months thereafter for analysis of the humoral immune response against the vaccine antigen. Results: Almost 50% of patients in this placebo-controlled study mount an immune response to IGN101. An interim analysis concerning survival of 45 stage IV colorectal cancer patients has been conducted without unblinding the data. The two groups compared were the immune-responders and the non-responders. Since the two groups reveal a distribution of almost 50% each, they may reflect the two treatment arms. Data showed a significant survival benefit for patients having mounted an immune response. No unexpected toxicities were observed. Conclusions: The blinded preliminary correlation analysis of survival and immune response indicate a promising activity of IGN101 in metastatic colorectal cancer. Study end and final analysis of unblinded data is planned for July 2004. Author Disclosure Employment or Leadership Consultant or Advisory Stock Ownership Honoraria Research Funding Expert Testimony Other Remuneration Igeneon Igeneon Igeneon Igeneon Krebs-Immun- therapie Forschungs- und Entwicklungs-AG

Induction as Consequence Finding

This paper presents a general procedure for inverse entailment which constructs inductive hypotheses in inductive logic programming. Based on inverse entailment, not only unit clauses but also characteristic clauses are deduced from a background theory together with the negation of positive examples. Such clauses can be computed by a resolution method for consequence finding. Unlike previous work on inverse entailment, our proposed method called CF-induction is sound and complete for finding hypotheses from full clausal theories, and can be used for inducing not only definite clauses but also non-Horn clauses and integrity constraints. We also show that CF-induction can be used to compute abductive explanations, and then compare induction and abduction from the viewpoint of inverse entailment and consequence finding.

Inductively Verifying Invariant Properties of Parameterized Systems

Verification of distributed algorithms can be naturally cast as verifying parameterized systems, the parameter being the number of processes. In general, a parameterized concurrent system represents an infinite family (of finite state systems) parameterized by a recursively defined type such as chains, trees. It is therefore natural to verify parameterized systems by inducting over this type. However, construction of such proofs require combination of model checking with deductive capability. In this paper, we develop a logic program transformation based proof methodology which achieves this combination. One of our transformations (unfolding) represents a single resolution step. Thus model checking can be achieved by repeated application of unfolding. Other transformations (such as folding) represent deductive reasoning and help recognize the induction hypothesis in an inductive proof. Moreover the unfolding and folding transformations can be arbitrarily interleaved in a proof, resulting in a tight integration of decision procedures (such as model checking) with deductive verification. Based on this technique, we have designed and implemented an invariant prover for parameterized systems. Our proof technique is geared to automate nested induction proofs which do not involve strengthening of induction hypothesis. The prover has been used to automatically verify invariant properties of parameterized cache coherence protocols, including broadcast protocols and protocols with global conditions. Furthermore, we have employed the prover for automatic verification of mutual exclusion in the Java Meta-Locking Algorithm. Meta-Locking is a distributed algorithm developed recently by designers in Sun Microsystems for ensuring secure access of Java objects by an arbitrary number of Java threads.