Minimal Version Research Articles

Online scheduling with rejection and withdrawal

We study an online scheduling problem with rejection, in which some rearrangement of the solution is allowed. This problem is called scheduling with rejection and withdrawal. Each arriving job has a processing time and a rejection cost associated with it, and it needs to be either assigned to a machine or rejected upon arrival. At termination, it is possible to choose at most a fixed number of scheduled jobs and withdraw them (i.e., decide to reject them). We study the minimization version, where the goal is to minimize the sum of the makespan and the total rejection cost (which corresponds to the penalty), and the maximization problem, where the goal is to maximize the sum of the minimum load and the total rejection cost (which corresponds to profit). We study environments of machines, which are the case of m identical machines and the case of two uniformly related machines, and show a strong relation between these problems and the related classic online scheduling problems which they generalize, in contrast to standard scheduling with rejection, which typically makes the scheduling problems harder.

A new proposal for the picture changing operators in the minimal pure spinor formalism

Using a new proposal for the "picture lowering" operators, we compute the tree level scattering amplitude in the minimal pure spinor formalism by performing the integration over the pure spinor space as a multidimensional Cauchy-type integral. The amplitude will be written in terms of the projective pure spinor variables, which turns out to be useful to relate rigorously the minimal and non-minimal versions of the pure spinor formalism. The natural language for relating these formalisms is the Cech-Dolbeault isomorphism. Moreover, the Dolbeault cocycle corresponding to the tree-level scattering amplitude must be evaluated in SO(10)/SU(5) instead of the whole pure spinor space, which means that the origin is removed from this space. Also, the Cech-Dolbeault language plays a key role for proving the invariance of the scattering amplitude under BRST, Lorentz and supersymmetry transformations, as well as the decoupling of unphysical states. We also relate the Green's function for the massless scalar field in ten dimensions to the tree-level scattering amplitude and comment about the scattering amplitude at higher orders. In contrast with the traditional picture lowering operators, with our new proposal the tree level scattering amplitude is independent of the constant spinors introduced to define them and the BRST exact terms decouple without integrating over these constant spinors.

In Vitro Selection of RNA Aptamer and Specific Targeting of ErbB2 in Breast Cancer Cells

The ErbB family (also referred to as HER/neu or HER) of receptor tyrosine kinases plays major roles in the formation and progression of human tumors. Amplification and/or overexpression of ErbB2 have been reported in numerous cancers, including breast, ovarian, stomach, bladder, salivary, and lung cancers. As ErbB2 has been used as a target for the treatment of advanced cancer, RNA aptamers for the extracellular domain of the ErbB2 were selected from a RNA library consisting of 2'-fluorine-modified RNA transcripts. After 15 cycles of selection, high-affinity RNA aptamer was isolated. Binding patterns of the selected RNA aptamer clones were evaluated to choose RNA aptamers that were specific to the extracellular domain of ErbB2 protein. RNA aptamer 15-8 was the best candidate and its minimal version (mini-aptamer) was chemically synthesized. Surface plasmon resonance measurement showed that the mini-aptamer specifically bound to the ErbB2 protein with high affinity and specificity. To evaluate its potential as an ErbB2-targeting molecule in breast cancer cells, specific recognition of the mini-aptamer was confirmed with various breast cancer cell lines. We propose that the selected RNA aptamer is a potential cancer imaging agent by targeting malignant cells overexpressing the ErbB2 receptor.

Supersymmetric left-right models with gauge coupling unification and fermion mass universality

We explore the unification of gauge couplings and fermion masses in two different types of supersymmetric left-right models, one with Higgs triplets and the other with both Higgs triplets as well as bitriplets. The minimal versions of these models do not give rise to the desired unification and some extra fields have to be added. After such a modification, it is possible in one model to get gauged $B-L$ symmetry to be unbroken down to TeV scale. We also identify the parameter space at the electroweak scale which gives rise to fermion mass unification at a high scale $M_{G}$. Type I seesaw emerges as the natural explanation of the small neutrino masses in both the models.

Effective two Higgs doublets in nonminimal supersymmetric models

The Higgs sectors of supersymmetric extensions of the Standard Model have two doublets in the minimal version (MSSM), and two doublets plus a singlet in two others: with (UMSSM) and without (NMSSM) an extra U(1)'. A very concise comparison of these three models is possible if we assume that the singlet has a somewhat larger breaking scale compared to the electroweak scale. In that case, the UMSSM and the NMSSM become effectively two-Higgs-doublet models (THDM), like the MSSM. As expected, the mass of the lightest CP-even neutral Higgs boson has an upper bound in each case. We find that in the NMSSM, this bound exceeds not very much that of the MSSM, unless tan(beta) is near one. However, the upper bound in the UMSSM may be substantially enhanced.

Vector- and scalar-bilepton pair production in hadron colliders

We study the double-charged vector-bilepton pair production and double-charged scalar-bilepton pair production {\it via} $p + p \longrightarrow Y^{++} + Y^{--} + X$ and $p + p \longrightarrow S_1^{++} + S_1^{--} + X$, where $Y$ and $S_1$ are vector and scalar bileptons respectively, in the framework of the minimal version of the 3-3-1 model. We compute the photon, $Z$, and $Z^\prime$ s-channel contributions for the elementary process of bilepton scalar pair production, and to keep the correct unitarity behavior for the elementary $q \bar q$ interaction, we include the exotic quark t-channel contribution in the vector-bilepton pair production calculation. We explore a mass range for $Z^\prime$ and we fix the exotic quark mass within the experimental bounds. In this model, the vector-bilepton mass is directly related to $M_{Z^\prime}$ and we consider scalar mass values around the vector-bilepton mass. We show that the total cross section for vector-bilepton production is 3 orders of magnitude larger than for scalar pair production for $\sqrt s= 7$ TeV and 14 TeV and we obtain the number of events for the proposed LHC luminosities as a function of the bilepton mass. In addition we present some invariant mass and transverse momentum distributions. When comparing these distributions we observe quite different behavior providing the determination of the bilepton nature. We conclude that one can disentangle the production rates and that the LHC can be capable of detecting these predicted particles as a signal for new physics.

ONLINE AND SEMI-ONLINE SCHEDULING ON CAPACITATED TWO-PARALLEL MACHINES

In this paper, we investigate the capacitated two-parallel machines scheduling problem, where one machine is only available for a special period of time after which it can no longer process any job while the other machine is continuously available. Our objective is to minimize the completion time of the machine which is continuously available. The offline version of the problem is equivalent to the minimization version of the Subset-Sum problem. We first show the lower bound of the online version is infinite. We also consider the semi-online version with known the total job processing time in advance, for which both lower bound and semi-online algorithms are given.

Top quark forward-backward asymmetry from the 3-3-1 model

The forward-backward asymmetry $A_{FB}$ in top quark pair production, measured at the Tevatron, is probably related to the contribution of new particles. The Tevatron result is more than a $2\sigma$ deviation from the standard model prediction and motivates the application of alternative models introducing new states. However, as the standard model predictions for the total cross section $\sigma_{tt}$ and invariant mass distribution $M_{tt}$ for this process are in good agreement with experiments, any alternative model must reproduce these predictions. These models can be placed into two categories: One introduces the s-channel exchange of new vector bosons with chiral couplings to the light quarks and to the top quark and another relies on the t-channel exchange of particles with large flavor-violating couplings in the quark sector. In this work we employ a model which introduces both s- and t-channel nonstandard contributions for the top quark pair production in proton antiproton collisions. We use the minimal version of the $SU(3)_C \otimes SU(3)_L \otimes U (1)_X$ model (3-3-1 model) that predicts the existence of a new neutral gauge boson, called $Z^\prime$. This gauge boson has both flavor-changing couplings to up and top quarks and chiral coupling to the light quarks and to the top quark. This very peculiar model coupling can correct the $A_{FB}$ for top quark pair production for two ranges of $Z^\prime$ mass while leading to cross section and invariant mass distribution quite similar to the standard model ones. This result reinforces the role of the 3-3-1 model for any new physics effect.

Scientific realism as a challenge to economics (and vice versa)

The implications of scientific realism in regard to economics depend on what one takes scientific realism to mean and on whether one lets its contents to depend on the peculiar characteristics of the discipline of economics. Here a revisionist line is adopted and scientific realism is reduced to a minimal version that is able to accommodate as large a portion of science as possible. Among other things, characterizations of minimal realism do not require, as standard formulations of scientific realism do, mind-independent existence, unobservables, and actual or likely epistemic and technological success. To accommodate economics, realism has to allow for ideas such as constitutive science-independence, commonsensibles, and the possibility of success. The task of turning the possibility into actual success is difficult, so requires attitudes such as humility and fallibilism as well as activities such as redesigning the institutions of inquiry.

Study of the temporal structure of the EAS neutron component

Experimental data on detecting the thermal neutrons that accompany extensive air showers (EAS) over a long period of time (May 2009–April 2010) are presented. The data were obtained by means of prototype for an innovative new array (PRISMA) for EAS study. The workability of this array and its ability to yield completely new information on the hadron and electron components of EAS was checked experimentally over long period of time (in the minimal version of the prototype).

Neutrino mass: From LHC to grand unification

The tiny neutrino masses and the associated large lepton mixings provide an interesting puzzle and a likely window to the physics beyond the standard model. This is certainly true if neutrinos are Majorana particles, since then, unlike in the Dirac case, the standard model is not a complete theory. The Majorana case leads to lepton number violation manifested through neutrinoless-double-beta decay and same-sign dileptons potentially accessible to colliders such as the LHC. This is covered at length. I discuss in these lectures possible theories of neutrino mass whose predictions are dictated by their structure only and this points strongly to grand unification. I cover in detail both SU(5) and SO(10) grand unified theories, and study the predictions of their minimal versions. The main message I wish to bring across is a serious hope of probing the origin of neutrino mass in near future, through the combined effort of high-energy collider and low-energy lepton number and lepton flavor violation experiments.

Bax-derived membrane-active peptides act as potent and direct inducers of apoptosis in cancer cells.

Although many cancer cells are primed for apoptosis, they usually develop resistance to cell death at several levels. Permeabilization of the outer mitochondrial membrane, which is mediated by proapoptotic Bcl-2 family members such as Bax, is considered as a point of no return for initiating apoptotic cell death. This crucial role has placed Bcl-2 family proteins as recurrent targets for anticancer drug development. Here, we propose and demonstrate a new concept based on minimal active versions of Bax to induce cell death independently of endogenous Bcl-2 proteins. We show that membrane-active segments of Bax can directly induce the release of mitochondria-residing apoptogenic factors and commit tumor cells promptly and irreversibly to caspase-dependent apoptosis. On this basis, we designed a peptide encompassing part of the Bax pore-forming domain, which can target mitochondria, induce cytochrome c release and trigger caspase-dependent apoptosis. Moreover, this Bax-derived 'poropeptide' produced effective tumor regression after peritumoral injection in a nude mouse xenograft model. Thus, peptides derived from proteins that form pores in the mitochondrial outer membrane represent novel templates for anticancer agents.

Minimal gaugomaly mediation

Mixed anomaly and gauge mediation (“gaugomaly” mediation) gives a natural solution to the SUSY flavor problem with a conventional LSP dark matter candidate. We present a minimal version of gaugomaly mediation where the messenger masses arise directly from anomaly mediation, automatically generating a messenger scale of order 50 TeV. We also describe a simple relaxation mechanism that gives rise to realistic μ and Bμ terms. B is naturally dominated by the anomaly-mediated contribution from top loops, so the μ-Bμ sector only depends on a single new parameter. In the minimal version of this scenario the full SUSY spectrum is determined by two continuous parameters (the anomaly-and gauge-mediated SUSY breaking masses) and one discrete parameter (the number of messengers). We show that these simple models can give realistic spectra with viable dark matter.

Structural changes in the SL5 and SL6 leader sequences of HIV-1 RNA following interactions with the viral mGag protein

We previously identified sequences downstream of the SL4 region of HIV-1 RNA that are involved in the recognition of the 5′ leader region of HIV-1 RNA by a minimal version of the HIV-1 Gag protein (mGag). These sequences increase the affinity of this interaction, promote Gag multimerization, and enhance formation of an early mGag–RNA complex. Now, we provide protein footprinting results on the +350 to +500 nucleotide region of viral RNA, based on use of different single-stranded and base-paired ribonucleases. Use of the mfold program confirmed the existence of both a stem-loop 5 (SL5), downstream of SL4, and a more complex multi-stem-loop structure (SL6). Footprinting analysis using mGag and single-stranded-specific nucleases showed almost complete protection of the single-stranded region. In contrast, results obtained with RNase V1, a double-stranded-specific nuclease, suggest that the RNA structure is changed upon protein binding, presumably because of formation of novel and longer stems. Furthermore, RNA footprinting, using viral nucleocapsid protein (NC) and RNase VI, indicate a highly double-stranded structure in several regions. These findings show that viral RNA structure is modified by interaction with proteins, and that NC may possess different chaperone activity in the context of the Gag precursor than in its mature form.

Asymmetric DNA recognition by the OkrAI endonuclease, an isoschizomer of BamHI

Restriction enzymes share little or no sequence homology with the exception of isoschizomers, or enzymes that recognize and cleave the same DNA sequence. We present here the structure of a BamHI isoschizomer, OkrAI, bound to the same DNA sequence (TATGGATCCATA) as that cocrystallized with BamHI. We show that OkrAI is a more minimal version of BamHI, lacking not only the N- and C-terminal helices but also an internal 310 helix and containing β-strands that are shorter than those in BamHI. Despite these structural differences, OkrAI recognizes the DNA in a remarkably similar manner to BamHI, including asymmetric contacts via C-terminal ‘arms’ that appear to ‘compete’ for the minor groove. However, the arms are shorter than in BamHI. We observe similar DNA-binding affinities between OkrAI and BamHI but OkrAI has higher star activity (at 37°C) compared to BamHI. Together, the OkrAI and BamHI structures offer a rare opportunity to compare two restriction enzymes that work on exactly the same DNA substrate.

Outcomes of Minimal and Moderate Support Versions of an Internet-Based Diabetes Self-Management Support Program

Internet and other interactive technology-based programs offer great potential for practical, effective, and cost-efficient diabetes self-management (DSM) programs capable of reaching large numbers of patients. This study evaluated minimal and moderate support versions of an Internet-based diabetes self-management program, compared to an enhanced usual care condition. A three-arm practical randomized trial was conducted to evaluate minimal contact and moderate contact versions of an Internet-based diabetes self-management program, offered in English and Spanish, compared to enhanced usual care. A heterogeneous sample of 463 type 2 patients was randomized and 82.5% completed a 4-month follow-up. Primary outcomes were behavior changes in healthy eating, physical activity, and medication taking. Secondary outcomes included hemoglobin A1c, body mass index, lipids, and blood pressure. The Internet-based intervention produced significantly greater improvements than the enhanced usual care condition on three of four behavioral outcomes (effect sizes [d] for healthy eating = 0.32; fat intake = 0.28; physical activity= 0.19) in both intent-to-treat and complete-cases analyses. These changes did not translate into differential improvements in biological outcomes during the 4-month study period. Added contact did not further enhance outcomes beyond the minimal contact intervention. The Internet intervention meets several of the RE-AIM criteria for potential public health impact, including reaching a large number of persons, and being practical, feasible, and engaging for participants, but with mixed effectiveness in improving outcomes, and consistent results across different subgroups. Additional research is needed to evaluate longer-term outcomes, enhance effectiveness and cost-effectiveness, and understand the linkages between intervention processes and outcomes.

Topological interactions in the Higgsless model at the LHC

Topological quantum interactions, namely Chern-Simons terms and global Wess-Zumino terms, arise naturally in theories with extra dimensions of space compactified on orbifolds. If the extra dimensions become manifest at the TeV scale, experiments at the Large Hadron Collider (LHC) could observe signatures of topological interactions. Decays of Kaluza-Klein excitations of neutral electroweak gauge bosons into pairs of neutral Standard Model gauge bosons, ZZ and Z+photon, would provide a clean signature, since such decays do not occur at tree level. In this paper, we investigate the prospects for discovering such decays at the LHC, in the context of the Higgsless model of electroweak symmetry breaking. We identify the form of the relevant topological interactions, and estimate their strength. We find that in the minimal version of the model, the signal may be observed with about 100 inverse fb of data at the LHC using the Drell-Yan production process of the Kaluza-Klein gauge bosons. In addition, it is likely that the ultraviolet completion of the model would contain additional massive fermions, which can significantly enhance the signal. With two additional fermion multiplets, observation of the topological decay modes at the 3-sigma level would be possible with about 100 inverse fb of data using the highly model-independent vector boson fusion production channel.

Tight constraints onF- andD-term hybrid inflation scenarios

We use present cosmological data from the cosmic microwave background, large-scale structure and deuterium at high redshifts to constrain supersymmetric F- and D-term hybrid inflation scenarios including possible contributions to the CMB anisotropies from cosmic strings. Using two different realizations of the cosmic string spectrum, we find that the minimal version of the D-term model is ruled out at high significance. F-term models are also in tension with the data. We also discuss possible non-minimal variants of the models.

On the sum minimization version of the online bin covering problem

Given a set of m identical bins of size 1, the online input consists of a (potentially infinite) stream of items in ( 0 , 1 ] . Each item is to be assigned to a bin upon arrival. The goal is to cover all bins, that is, to reach a situation where a total size of items of at least 1 is assigned to each bin. The cost of an algorithm is the sum of all used items at the moment when the goal is first fulfilled. We consider three variants of the problem, the online problem, where there is no restriction of the input items, and the two semi-online models, where the items arrive sorted by size, that is, either by non-decreasing size or by non-increasing size. The offline problem is considered as well.

Searching for an extra neutral gauge boson from muon pair production at LHC

We search for signatures of the extra neutral gauge boson Z′, predicted in some extensions of the Standard Model, from the analysis of some distributions for p+p→μ++μ−+X, where the only exotic particle involved is Z′. In addition to the invariant mass and charge asymmetry distributions, we propose in our search to use the transverse momentum distribution (pT) as an observable. We do our calculation for two values of the LHC center of mass energy (7 and 14 TeV), corresponding to 1 and 100 fb−1 of luminosity, in order to compare our findings from some models with the distributions following from the Standard Model. By applying convenient cuts in the invariant mass, we show that the final particles pT distributions can reveal the presence of an extra neutral gauge boson contribution. We also claim that it is possible to disentangle the models considered here and we emphasize that the minimal version of the model, based on SU(3)C×SU(3)L×U(1)X symmetry, presents the more clear signatures for Z′ existence.