“It is hard right now”: High School Educators Working with Undocumented Students

This project began with an interest in learning about the experiences of educators working with undocumented high school students in San Diego County. The backdrop for this study is the current anti-immigrant climate, specifically targeting Latinx undocumented immigrants. Educators in the San Diego County are working in a context where immigration authorities are deporting their students’ family members. Our aim is to begin painting a picture of who these educators are and some of the practices they employ to support their undocumented students. We hope our findings will begin to support educators and in turn their students

Building GUTs from strings

We study in detail the structure of Grand Unified Theories derived as the low-energy limit of orbifold four-dimensional strings. To this aim, new techniques for building level-two symmetric orbifold theories are presented. New classes of GUTs in the context of symmetric orbifolds are then constructed. The method of permutation modding is further explored and SO(10) GUTs with both $45$ or $54$-plets are obtained. SU(5) models are also found through this method. It is shown that, in the context of symmetric orbifold $SO(10)$ GUTs, only a single GUT-Higgs, either a $54$ or a $45$, can be present and it always resides in an order-two untwisted sector. Very restrictive results also hold in the case of $SU(5)$. General properties and selection rules for string GUTs are described. Some of these selection rules forbid the presence of some particular GUT-Higgs couplings which are sometimes used in SUSY-GUT model building. Some semi-realistic string GUT examples are presented and their properties briefly discussed.Comment: 40 pages, no figures, Late

Heightened Uncertainty and Determination: The “Trump Effect” and College Aspirations for Undocumented Students

This article examines the educational experiences of undocumented high school students during the Trump administration—a time marked by the intensification and expansion of immigration enforcement practices. Drawing on 24 in-depth interviews, we find that undocumented high school students experienced increased instances of bullying near the time of the 2016 U.S. presidential elections. Our respondents also worried about the growing uncertainty surrounding immigration policies and the future of DACA. This uncertainty shaped their plans; many students felt compelled to prioritize working and delay starting college to make use of their work permit while they had access to DACA and build emergency savings. While the current political climate gravely exacerbated students’ fear and anxiety, students demonstrated a tremendous amount of resiliency, agency, and determination to achieve their goals. We find that access to a support network and encouraging school personnel played a key role. Thus, we conclude this article with a set of key recommendations for educators and counselors who are working with undocumented students and their families on the ground

Inflation with Non-minimal Gravitational Couplings and Supergravity

We explore in the supergravity context the possibility that a Higgs scalar may drive inflation via a non-minimal coupling to gravity characterised by a large dimensionless coupling constant. We find that this scenario is not compatible with the MSSM, but that adding a singlet field (NMSSM, or a variant thereof) can very naturally give rise to slow-roll inflation. The inflaton is necessarily contained in the doublet Higgs sector and occurs in the D-flat direction of the two Higgs doublets.Comment: 13 pages, 1 figur

Fermion mass relations in a supersymmetric SO(10) theory

Neutrino and charged fermion masses provide important constraints on grand unified theories. We illustrate this by focusing on a renormalizable, supersymmetric SO(10) theory proposed long ago, that recently attracted great interest in view of its minimality. We show how the nature of the light Higgs, which depends on the GUT scale fields, gets reflected on the precise predictions for fermion masses and mixings. We exemplify this on the case of dominant Type II see-saw, which gets severely constrained and is likely to fail.Comment: Based on talks given by G. Senjanovic in the plenary session of PASCOS05 Conference and by A. Melfo at the 2005 Gran Sasso Summer Institut

On Gauge Couplings in String Theory

We investigate the field dependence of the gauge couplings of $N=1$ string vacua from the point of view of the low energy effective quantum field theory. We find that field-theoretical considerations severely constrain the form of the string loop corrections; in particular, the dilaton dependence of the gauge couplings is completely universal at the one-loop level. The moduli dependence of the string threshold corrections is also constrained, and we illustrate the power of such constraints with a detailed discussion of the orbifold vacua and the $(2,2)$ (Calabi-Yau) vacua of the heterotic string.Comment: 82 pages, 6 in-line figures, uses phyzzx.tex and epsf.tex macro

Field Dependent Gauge Couplings in Locally Supersymmetric Effective Quantum Field Theories

We investigate the field dependence of the gauge couplings of locally supersymmetric effective quantum field theories. We find that the Weyl rescaling of supergravity gives rise to Wess-Zumino terms that affect the gauge couplings at the one-loop level. These Wess-Zumino terms are crucial in assuring supersymmetric consistency of both perturbative and non-perturbative gauge interactions. At the perturbative level, we distinguish between the holomorphic Wilsonian gauge couplings and the physically-measurable momentum-dependent effective gauge couplings; the latter are affected by the Konishi and the super-Weyl anomalies and their field-dependence is non-holomorphic. At the non-perturbative level, we show how consistency of the scalar potential generated by infrared-strong gauge interactions with the local supersymmetry requires a very specific form of the effective superpotential. We use this superpotential to determine the dependence of the supersymmetric condensates of a strongly interacting gauge theory on its (field-dependent) Wilsonian gauge coupling and the Yukawa couplings of the matter fields. The article concludes with the discussion of the field-dependent non-perturbative phenomena in the context of string unification.Comment: UTTG-94-1 and LMU-TPW-94-1 (107 pages, PHYZZX macros; EPSF figures appended

Modelling the supernova-driven ISM in different environments

We use hydrodynamical simulations in a (256 pc)3 periodic box to model the impact of supernova (SN) explosions on the multiphase interstellar medium (ISM) for initial densities n=0.5-30cm−3 and SN rates 1-720Myr−1. We include radiative cooling, diffuse heating, and the formation of molecular gas using a chemical network. The SNe explode either at random positions, at density peaks, or both. We further present a model combining thermal energy for resolved and momentum input for unresolved SNe. Random driving at high SN rates results in hot gas (T≳106K) filling >90 per cent of the volume. This gas reaches high pressures (10450 per cent), residing in small, dense clumps. Such a model might resemble the dense ISM in high-redshift galaxies. Peak driving results in huge radiative losses, producing a filamentary ISM with virtually no hot gas, and a small molecular hydrogen mass fraction (≪1 per cent). Varying the ratio of peak to random SNe yields ISM properties in between the two extremes, with a sharp transition for equal contributions. The velocity dispersion in H i remains≲10 km s−1 in all cases. For peak driving, the velocity dispersion in Hα can be as high as 70 km s−1 due to the contribution from young, embedded SN remnant