Loosely bound hyperons in the SU(3) Skyrme model

Hyperon pairs bound in deuteron like states are obtained within the SU(3) Skyrme model in agreement with general expectations from boson exchange models. The central binding from the flavor symmetry breaking terms increases with the strangeness contents of the interacting baryons whereas the kinetic non-linear $\sigma$-model term fixes the spin and isospin of the bound pair. We give a complete account of the interactions of octet baryons within the product approximation to baryon number $B=2$ configurations.Comment: 35 pages REVTEX including 2 figs, with 3 further figs available on request from [email protected] or from [email protected] SI-94-TP3S2; STPHY-Th/94-

Sigma Exchange in the Nonmesonic Decays of Light Hypernuclei and Violation of the Delta I=1/2 Rule

Nonmesonic weak decays of s-shell hypernuclei are analyzed in microscopic models for the Lambda N to NN weak interaction. A scalar-isoscalar meson, sigma, is introduced and its importance in accounting the decay rates, n/p ratios and proton asymmetry is demonstrated. Possible violation of the Delta I=1/2 rule in the nonmesonic weak decay of Lambda is discussed in a phenomenological analysis and several useful constraints are presented. The microscopic calculation shows that the current experimental data indicate a large violation of the Delta I=1/2 rule, although no definite conclusion can be derived due to large ambiguity of the decay rate of {^4_Lambda H}.Comment: 13 pages, 5 figure

SIMP (Strongly Interacting Massive Particle) Search

We consider laboratory experiments that can detect stable, neutral strongly interacting massive particles (SIMPs). We explore the SIMP annihilation cross section from its minimum value (restricted by cosmological bounds) to the barn range, and vary the mass values from a GeV to a TeV. We also consider the prospects and problems of detecting such particles at the Tevatron.Comment: Latex. 7 pages, 1 eps figure. Proceedings to the 4th UCLA Symposium on Dark Matter DM2000, Marina del Rey, CA, USA, Feb. 23-25, 200

The influence of strength of hyperon-hyperon interactions on neutron star properties

An equation of state of neutron star matter with strange baryons has been obtained. The effects of the strength of hyperon-hyperon interactions on the equations of state constructed for the chosen parameter sets have been analyzed. Numerous neutron star models show that the appearance of hyperons is connected with the increasing density in neutron star interiors. The performed calculations have indicated that the change of the hyperon-hyperon coupling constants affects the chemical composition of a neutron star. The obtained numerical hyperon star models exclude large population of strange baryons in the star interior.Comment: 18 pages, 22 figures, accepted to be published in Journal of Physics G: Nuclear and Particle Physic

Production of Strange Clusters and Strange Matter in Nucleus-Nucleus Collisions at the AGS

Production probabilities for strange clusters and strange matter in Au+Au collisions at AGS energy are obtained in the thermal fireball model. The only parameters of the model, the baryon chemical potential and temperature, were determined from a description of the rather complete set of hadron yields from Si+nucleus collisions at the AGS. For the production of light nuclear fragments and strange clusters the results are similar to recent coalescence model calculations. Strange matter production with baryon number larger than 10 is predicted to be much smaller than any current experimental sensitivities.Comment: 9 Pages (no figures

Discrimination and Perceived Cultural Mismatch Increase Status-Based Identity Uncertainty

Periods of social mobility, such as attending college, can challenge one’s status-based identity, leading to uncertainty around one’s status in society. Status uncertainty is associated with poorer well-being and academic outcomes. Little is known, however, about what experiences lead to status uncertainty. The current longitudinal study investigated discrimination experiences and cultural mismatch as predictors of status uncertainty. We propose that discrimination indirectly predicts increased status uncertainty by increasing perceived cultural mismatch with the university. Participants were Latinx college students, all of whom were low-income and/or first generation to college. Discrimination experiences were measured at the end of participants’ first year. Cultural mismatch and status uncertainty were measured at the end of Year 2. Status uncertainty was measured again at the end of Year 3. Results indicated that students who experienced more frequent discrimination felt more cultural mismatch 1 year later, and, in turn, reported increased status uncertainty over the following year

Hyperon-nucleon scattering and hyperon masses in the nuclear medium

We analyze low-energy hyperon-nucleon scattering using an effective field theory in next-to-leading order. By fitting experimental cross sections for laboratory hyperon momenta below 200 MeV/c and using information from the hypertriton we determine twelve contact-interaction coefficients. Based on these we discuss the low-density expansion of hyperon mass shifts in the nuclear medium.Comment: 10 pages, 2 figure

In Vitro and In Vivio Evaluation of a Moisture Treatment Cream Containing Three Critical Elements of Natural Skin Moisturization

Objectives To evaluate skin barrier and hydration effects of a new rebalancing moisture treatment (TRMT) and to assess efficacy and tolerability in subjects with photodamaged skin. Methods In an epidermal skin model, tissues (n = 5/group) were topically treated with 25 µL of TRMT, 25 µL of a market‐leading moisturizer (MLM), or untreated for 60 minutes. Hydration was measured at 0, 15, and 30 minutes. Tissues were harvested for gene expression analysis of markers associated with skin barrier and hydration: Claudin (CLD), Aquaporin (AQP), Hyaluronic Acid Syntheses (HAS), and Hyaluronidase (HYAL). A clinical study evaluated twice‐daily application of TRMT, assessing changes in fine lines/wrinkles, brightness, texture, erythema, and tolerability from baseline through week 8. Hydration was measured using electrical impedance. Results TRMT and MLM demonstrated significant increases in hydration vs untreated tissue at each timepoint (P \u3c .005), with greater hydration effects observed for TRMT vs MLM. TRMT‐treated tissues demonstrated greater expression of CLD, AQP, and HA, and reduced expression of HYAL vs untreated and MLM‐treated tissues. Twice‐daily application of TRMT demonstrated significant improvements at 2 weeks in fine lines/wrinkles (P \u3c .001), brightness (P \u3c .0001), texture (P \u3c .0004), and hydration (P \u3c .004). At 8 weeks, statistically significant improvements were achieved in all categories. Conclusion In an epidermal skin model, TRMT demonstrated significant increases in hydration, greater hydration effects, and expression of key markers associated with skin barrier and hydration vs a MLM. Twice‐daily application of TRMT was well tolerated and resulted in early, significant improvements in hydration and visible improvements in skin brightness, texture, fine lines/wrinkles, and erythema at 8 weeks

Ocean Science in The SMILE Program : Combining Ocean Literacy and Concept Mapping as an Aid for Curriculum Development

This study reports on the creation and testing of a model concept-mapping process that will aid the development and documentation of ocean science educational content of The Science and Math Investigative Learning Experiences (SMILE) Program, a pre-college science and math enrichment program based at Oregon State University. The project uses the professional knowledge of SMILE high school teachers and staff to pilot a curriculum development process. This process highlights one of the seven Essential Principles of Ocean Literacy to produce ideas for educational activities that will facilitate learning of that principle by students in SMILE after school clubs. Specifically, participants generate activity topics linked to the ocean literacy principle by producing concept maps of the underlying fundamental concepts of that principle. The concept-mapping process collaboratively identifies 12 specific themes that should be included in SMILE ocean science curriculum to enable students to fully comprehend the chosen principle. Semi-structured interviews with key informants found that support for the future application of the process is positive, but requires modification to make it a) part of regular programming, b) more time efficient and c) more directly applicable to other informal education settings. This study also bridges the gap between the curriculum that SMILE provides to it’s after school clubs and teacher professional recommendations on what should be included in this curriculum