On the cost of misperceived travel time variability

Recent studies show that traveler’s scheduling preferences compose a willingness-to-pay function directly corresponding to aggregate measurement of travel time variability under some assumptions. This property makes valuation on travel time variability transferable from context to context, which is ideal for extensive policy evaluation. However, if respondents do not exactly maximizing expected utility as assumed, such transferability might not hold because two types of potential errors: (i) scheduling preference elicited from stated preference experiment involving risk might be biased due to misspecification and (ii) ignoring the cost of misperceiving travel time distribution might result in undervaluation. To find out to what extent these errors matter, we reformulate a general scheduling model under rank-dependent utility theory, and derive reduced-form expected cost functions of choosing suboptimal departure time under two special cases. We estimate these two models and calculate the empirical cost due to misperceived travel time variability. We find that (i) travelers are mostly pessimistic and thus tend to choose departure time too earlier to bring optimal cost, (ii) scheduling preference elicited from stated choice method could be quite biased if probability weight- ing is not considered and (iii) the extra cost of misperceiving travel time distribution contributes trivial amount to the discrepancy between scheduling model and its reduced form

PC12細胞においてノイロトロピンはTrk神経栄養因子受容体とガングリオシドGM1の会合を介してNGFシグナル伝達を促進する

藤田保健衛生大

ABCB6 Is a Porphyrin Transporter with a Novel Trafficking Signal That Is Conserved in Other ABC Transporters

The ATP-binding cassette (ABC) transporters play an important role as a barrier to protect cells from the accumulation of toxic xenobiotics and metabolites due to their ability to translocate a wide array of compounds across lipid bilayers. However, many ABC transporters, especially the ones localized in the intracellular organelles, are involved in critical biological processes such as antigen presentation. The core unit of ABC transporters contains two functional domains: the membrane spanning domain (MSD) and the nucleotide binding domain. The full transporters contain two of these units in tandem in a single polypeptide, whereas the half transporters only contain one and must homo- or hetero-dimerize in order to exert their functions. A half transporter ABCB6 has been shown to localize in mitochondria and suggested to play a role in iron homeostasis; however, its function remained elusive. Therefore, we aimed to characterize several aspects of ABCB6: identification of substrates, physiological role, transport mechanism and intracellular trafficking. In this study, we show that ABCB6 is a homodimeric mitochondrial outer membrane protein. Furthermore, we identified ABCB6 as a porphyrin transporter that facilitates heme biosynthesis, in which the intermediates must be shuttled between mitochondria and the cytosol. Translocation of substrates by ABC transporters occurs in an ATP-dependent manner, although the role of ATP binding and hydrolysis in the transport process remains controversial. Taking advantage of its ability to bind hemin conjugated to agarose beads, we demonstrate that the ATP binding at the NBD is sufficient to induce a conformational change to a low affinity state in ABCB6. In an attempt to understand how ABCB6 trafficks intracellularly, we identified a post-translational modification that indicates ER to Golgi trafficking during its maturation. Moreover, we identified a novel N-terminal disulfide bond that plays an important role in the ER exit of ABCB6. This disulfide bond motif is found in other ABC family members and the loss of the conserved cysteine residue in ABCC8/SUR1 is the genetic basis for hyperinsulinemic hypoglycemia. Because ER redox status appears to play an important role in the trafficking of these proteins, expression patterns of ABC transporters may be altered in pathophysiological conditions such as diabetes where microsomal redox status is shifted

Single Pion Production in Neutrino Reactions and Estimates for Charge-Exchange Effects

We calculate single pion production by neutrinos in the resonance region. We consider both charged and neutral current reactions on free protons and neutrons. We present differential and total cross sections which can be compared with experiments. Then we use these results to calculate the spectra of the emerging pions including the Pauli suppression factor and rescattering corrections for reactions in heavy nuclei. Our results will be useful for studying single pion production and for investigating neutrino oscillations in future experiments.Comment: 20 pages, 16 figure

Bimaximal Neutrino Mixing in a Zee-type Model with Badly Broken Flavor Symmetry

A Zee-type neutrino mass matrix model with a badly broken horizontal symmetry SU(3)_H is investigated. By putting a simple ansatz on the symmetry breaking effects of SU(3)_H for transition matrix elements, it is demonstrated that the model can give a nearly bimaximal neutrino mixing with the ratio $\Delta m^2_{solar}/\Delta m^2_{atm} \simeq \sqrt{2} m_e/m_{\mu}=6.7 \times 10^{-3}$, which are in excellent agreement with the observed data. In the near future, the lepton-number violating decay $Z\to \mu^\pm \tau^\mp$ will be observed.Comment: 10 pages, no figures, a comment adde

Off-diagonal structure of neutrino mass matrix in see-saw mechanism and electron-muon-tau lepton universality

By a simple extension of the standard model in which ($e-\mu -\tau$) universality is not conserved, we present a scenario within the framework of see-saw mechanism in which the neutrino mass matrix is strictly off-diagonal in the flavor basis. We show that a version of this scenario can accomodate the atmospheric $\nu_\mu -\nu_\tau$ neutrino oscillations and $\nu_\mu -\nu_e$ oscillations claimed by the LSND collaboration. PACS: 14.60.Pq; 14.60.St;13.15.+gComment: 5 pages, Revtex, 1 figure: The model accomodate another version which explains atmospheric neutrino data and the observed solar neutrino oscillations (large angle solution). In the previous version the value of \lambda parameter is changed to the expected one. This version now accomodates LSND result and solar neutrino oscillations (small angle MSW solution

What will the first year of SNO show?

The ratio of the measured to the predicted standard model CC event rates in SNO will be 0.47 if no oscillations occur. The best-fit active oscillation predictions for the CC ratio are: 0.35-39 (MSW) and 0.38-42 (vacuum) (all for a 5 MeV energy threshold), typically about 20% less than the no-oscillation expectation. We calculate the predicted ratios for six active and sterile neutrino oscillation solutions allowed at 99% CL and determine the dependence of the ratios on energy threshold. If the high-energy anomaly observed by SuperKamiokande is due to an enhanced hep flux, MSW active solutions predict that out of a total of 5000 CC events above 5 MeV in SNO between 49 and 54 events will be observed above 13 MeV whereas only 19 events are expected for no-oscillations and a nominal standard hep flux.Comment: Phys Lett accepted. Editorial corrections. Related material and viewgraphs at http://www.sns.ias.edu/~jn