Flavor changing neutral current constraints on standard-like orbifold models

We examine for standard-like orbifold compactification models the constraints due to quarks and leptons generation non-universality of soft supersymmetry breaking interactions. We follow the approach initiated by Ibanez and Lust and developed by Brignole, Ibanez and Munoz. The breaking of supersymmetry is represented in terms of dilaton and moduli auxiliary field components and, consistently with a vanishing cosmological constant, is parametrized in terms of the dilaton-moduli mixing angle $\theta$ and the gravitino mass scale $m_g$. The soft breaking interactions (gaugino masses, squarks and sleptons mass matrices, scalars interactions A and B coupling constants) are calculable as a function of these parameters and of the discrete set of modular weight parameters specifying the modular transformation properties of the low-energy fields. We solve the renormalization group one-loop equations for the full set of gauge, Yukawa and supersymmetry breaking coupling constants.Comment: 32 page

Gauge and Matter Condensates in Realistic String Models

We examine the inter-relationship of the superpotential containing hidden and observable matter fields and the ensuing condensates in free fermionic string models. These gauge and matter condensates of the strongly interacting hidden gauge groups play a crucial role in the determination of the physical parameters of the observable sector. Supplementing the above information with the requirement of modular invariance, we find that a generic model with only trilinear superpotential allows for a degenerate (and sometimes pathological) set of vacua. This degeneracy may be lifted by higher order terms in the superpotential. We also point out some other subtle points that may arise in calculations of this nature. We exemplify our observations by computing explicitly the modular invariant gaugino and matter condensates in the flipped SU(5) string model with hidden gauge group $SO(10)\times SU(4)$.Comment: 11 pages (7 if reduced

One-loop Correction and the Dilaton Runaway Problem

We examine the one-loop vacuum structure of an effective theory of gaugino condensation coupled to the dilaton for string models in which the gauge coupling constant does not receive string threshold corrections. The new ingredients in our treatment are that we take into account the one-loop correction to the dilaton K\"ahler potential and we use a formulation which includes a chiral field $H$ corresponding to the gaugino bilinear. We find through explicit calculation that supersymmetry in the Yang-Mills sector is broken by gaugino condensation. The dilaton and $H$ field have masses on the order of the gaugino condensation scale independently of the dilaton VEV. Although the calculation performed here is at best a model of the full gaugino condensation dynamics, the result shows that the one-loop correction to the dilaton K\"ahler potential as well as the detailed dynamics at the gaugino condensation scale may play an important role in solving the dilaton runaway problem.Comment: 19 page

Effect of supercritical CO2 and olive leaf extract on the structural, thermal and mechanical properties of an impregnated food packaging film

Poly(ethylene terephthalate)/polypropylene (PET/PP) films containing olive leaf extract (OLE) were obtained by supercritical solvent impregnation (SSI) in batch (BM) and semi-continuous (SM) modes. The study focused on the impact of pressure, temperature, CO2 flow and OLE on the properties of the impregnated films. Thermal analysis of non-impregnated samples revealed a decrease in the crystallinity of PP layer treated at 35 °C and an increase in the Tg of PET treated at 55 °C due to CO2 sorption. In impregnated samples, high pressures caused a decrease in the crystallinity of PP layer, whereas PET layer remained unaffected. Higher pressures favour impregnation in BM, whereas different trends were found for SM impregnations. Although the film properties were not compromised after impregnation, the CO2 stream used in SM slightly weakened the impregnated films. Overall, conditions of 400 bar and 35 °C in BM were favorable for producing highly antioxidant films with minor structural modifications

A Shift Symmetry in the Higgs Sector: Experimental Hints and Stringy Realizations

We interpret reported hints of a Standard Model Higgs boson at ~ 125 GeV in terms of high-scale supersymmetry breaking with a shift symmetry in the Higgs sector. More specifically, the Higgs mass range suggested by recent LHC data extrapolates, within the (non-supersymmetric) Standard Model, to a vanishing quartic Higgs coupling at a UV scale between 10^6 and 10^18 GeV. Such a small value of lambda can be understood in terms of models with high-scale SUSY breaking if the Kahler potential possesses a shift symmetry, i.e., if it depends on H_u and H_d only in the combination (H_u+\bar{H}_d). This symmetry is known to arise rather naturally in certain heterotic compactifications. We suggest that such a structure of the Higgs Kahler potential is common in a wider class of string constructions, including intersecting D7- and D6-brane models and their extensions to F-theory or M-theory. The latest LHC data may thus be interpreted as hinting to a particular class of compactifications which possess this shift symmetry.Comment: v2: References added. v3: References added, published versio

Theory-Motivated Benchmark Models and Superpartners at the Tevatron

Recently published benchmark models have contained rather heavy superpartners. To test the robustness of this result, several benchmark models have been constructed based on theoretically well-motivated approaches, particularly string-based ones. These include variations on anomaly and gauge-mediated models, as well as gravity mediation. The resulting spectra often have light gauginos that are produced in significant quantities at the Tevatron collider, or will be at a 500 GeV linear collider. The signatures also provide interesting challenges for the LHC. In addition, these models usually account for electroweak symmetry breaking with relatively less fine-tuning than previous benchmark models.Comment: 44 pages, 4 figures; some typos corrected. Revisions reflect published versio

The b--->s{\gamma} constraint in effective supergravities from string theory

We study the constraints from the $b{\rightarrow}s{\gamma}$ decay in the parameter space of effective supergravities from orbifold string theory and with minimal supesymmetric particle content. Both the general dilaton-dominated universal scenario as well as a non-universal scenario for the soft terms are investigated. It is found that the recently reported CLEO upper and lower bounds constrain the parameter space of the models under scrutiny. In particular we find constraints on the values of the parameter $\tan{\beta}$ and the gluino masses. In this class of string scenarios the negative sign of the Higgs mixing parameter $\mu$, is phenomenologically preferred.Comment: LaTeX 11 pages, figures uuencoded included in a separate file, some typos have been corrected,1 figure adde

Supersymmetry and Superstring Phenomenology

We briefly cover the early history of supersymmetry, describe the relation of SUSY quantum field theories to superstring theories and explain why they are considered a likely tool to describe the phenomenology of high energy particle theory beyond the Standard Model.Comment: 18 pages. To be published in ``Supersymmetry on the Eve of the LHC'', a special volume of the European Physical Journal C (EPJC) dedicated to the memory of Julius Wes

Defining Chlorophyll-a Reference Conditions in European Lakes

The concept of “reference conditions” describes the benchmark against which current conditions are compared when assessing the status of water bodies. In this paper we focus on the establishment of reference conditions for European lakes according to a phytoplankton biomass indicator—the concentration of chlorophyll-a. A mostly spatial approach (selection of existing lakes with no or minor human impact) was used to set the reference conditions for chlorophyll-a values, supplemented by historical data, paleolimnological investigations and modelling. The work resulted in definition of reference conditions and the boundary between “high” and “good” status for 15 main lake types and five ecoregions of Europe: Alpine, Atlantic, Central/Baltic, Mediterranean, and Northern. Additionally, empirical models were developed for estimating site-specific reference chlorophyll-a concentrations from a set of potential predictor variables. The results were recently formulated into the EU legislation, marking the first attempt in international water policy to move from chemical quality standards to ecological quality targets

Guidelines for the use and interpretation of assays for monitoring autophagy (3rd edition)

In 2008 we published the first set of guidelines for standardizing research in autophagy. Since then, research on this topic has continued to accelerate, and many new scientists have entered the field. Our knowledge base and relevant new technologies have also been expanding. Accordingly, it is important to update these guidelines for monitoring autophagy in different organisms. Various reviews have described the range of assays that have been used for this purpose. Nevertheless, there continues to be confusion regarding acceptable methods to measure autophagy, especially in multicellular eukaryotes. For example, a key point that needs to be emphasized is that there is a difference between measurements that monitor the numbers or volume of autophagic elements (e.g., autophagosomes or autolysosomes) at any stage of the autophagic process versus those that measure fl ux through the autophagy pathway (i.e., the complete process including the amount and rate of cargo sequestered and degraded). In particular, a block in macroautophagy that results in autophagosome accumulation must be differentiated from stimuli that increase autophagic activity, defi ned as increased autophagy induction coupled with increased delivery to, and degradation within, lysosomes (inmost higher eukaryotes and some protists such as Dictyostelium ) or the vacuole (in plants and fungi). In other words, it is especially important that investigators new to the fi eld understand that the appearance of more autophagosomes does not necessarily equate with more autophagy. In fact, in many cases, autophagosomes accumulate because of a block in trafficking to lysosomes without a concomitant change in autophagosome biogenesis, whereas an increase in autolysosomes may reflect a reduction in degradative activity. It is worth emphasizing here that lysosomal digestion is a stage of autophagy and evaluating its competence is a crucial part of the evaluation of autophagic flux, or complete autophagy. Here, we present a set of guidelines for the selection and interpretation of methods for use by investigators who aim to examine macroautophagy and related processes, as well as for reviewers who need to provide realistic and reasonable critiques of papers that are focused on these processes. These guidelines are not meant to be a formulaic set of rules, because the appropriate assays depend in part on the question being asked and the system being used. In addition, we emphasize that no individual assay is guaranteed to be the most appropriate one in every situation, and we strongly recommend the use of multiple assays to monitor autophagy. Along these lines, because of the potential for pleiotropic effects due to blocking autophagy through genetic manipulation it is imperative to delete or knock down more than one autophagy-related gene. In addition, some individual Atg proteins, or groups of proteins, are involved in other cellular pathways so not all Atg proteins can be used as a specific marker for an autophagic process. In these guidelines, we consider these various methods of assessing autophagy and what information can, or cannot, be obtained from them. Finally, by discussing the merits and limits of particular autophagy assays, we hope to encourage technical innovation in the field