Sulfur and lime affect soil pH and nutrients in a sandy Pinus taeda nursery

Two pH experiments were conducted at a sandy, bareroot loblolly pine (Pinus taeda L.) nursery in Texas. A sulfur trial (0, 813, 1626, 2439 kg ha-1 of elemental sulfur) was installed to determine if lowering soil pH would result in nutrient toxicity symptoms and affect seedling morphology. Although soil acidity in the sulfur study ranged from pH 3.9 to pH 5.0, none of the treatments resulted in micronutrient toxicity and none affected height growth, root-collar diameter, root mass, shoot mass or the root-mass ratio (root dry mass/total dry mass). Acidifying soil with sulfur increased leaching of calcium, potassium, magnesium, manganese and zinc but there was no effect on seedling morphology. The objective of the liming trial (0, 813, 1626, 3252 kg ha-1 of dolomitic lime) was to determine if increasing alkalinity would result in an iron deficiency and reduce seedling growth. As expected, applying lime increased the calcium and magnesium levels but had no effect on soil levels of iron, phosphorus, potassium, sulfur, zinc and sodium. However, the root-mass ratio was reduced by applications of dolomitic lime (pH ranged from 5.3 to 6.0). Differences in soil properties (i.e. plot location) had a greater effect on seedling morphology than lime applications. Foliage levels of manganese and boron were reduced by the highest rate of lime and sulfur, respectively

THE INTERPLAY OF THE K+K- ATOM AND THE f_0(975) RESONANCE

We predict that production of the K+K- atom in pd-3^HeX and similar reactions exhibits a drastic missing mass spectrum due to the interplay with f_0(975) resonance. We point out that high precision studies of the K+K- atom may shed a new light on the nature of f_0(975).Comment: 13 page

Five Principles for Reforming Developmental Education: A Review of the Evidence

Over the past decade, policymakers, educators, and administrators in community colleges and other broad-access postsecondary institutions have focused on reforming developmental education practices, including how students are assessed as needing additional academic support. Concurrent with widespread changes in practice, researchers have engaged in efforts to study and evaluate interventions that colleges have undertaken to improve outcomes of students traditionally referred to developmental education. In this report, the authors review both impact and implementation studies published between 2010 and 2022 in order to summarize the current understanding of how innovations to developmental education can improve student outcomes. Relying primarily on 17 experimental and quasi-experimental studies of innovative developmental education interventions that meet rigorous research standards, they outline five principles with embedded implementation lessons that are key for colleges that want to engage in developmental education reform. The authors also consider how well developmental education reforms are working for students traditionally underserved in higher education, including students who are Black, Latinx, and from low-income backgrounds, and students with greater academic needs. The five principles are as follows: Grant students access to college-level math and English courses. Provide targeted and tiered supports to address students’ academic and nonacademic needs. Employ contextualized curriculum and student-centered pedagogy. Use equity-minded approaches for design and implementation. Implement developmental education reforms alongside comprehensive, sustained supports to improve long-term outcomes. The authors also use this review to identify areas in which stronger evidence is needed for guiding reform efforts. They argue that future research should aim to uncover specific policies and practices in institutions and classrooms that serve as barriers to racially minoritized students, and they note that more knowledge is required on how to support students with greater academic and nonacademic needs. They also discuss the costs of various reforms and note that more cost-effectiveness research is needed on interventions and strategies such as corequisite support courses and granting students direct access to college-level courses without support. To supplement the findings and recommendations, CAPR invited four individuals knowledgeable about developmental education to respond to the report based on their own experiences and perspectives. These take the form of short essays found in the companion document Four Responses to the Report

Pions in the nuclear medium and Drell-Yan scattering

We investigate the modification of the pion-cloud in the nuclear medium and its effect on the nuclear Drell-Yan process. The pion's in-medium self-energy is calculated in a self-consistent delta-hole model, with particle-hole contribution also included. Both the imaginary and real part of the pion's and delta's self-energy are taken into account and related through a dispersion relation assuring causality. The resulting in-medium pion light-cone momentum distribution shows only a slight enhancement compared to the one of the free nucleon. As a consequence the ratio of the cross-section for Drell-Yan scattering on nuclear matter and nucleonic target is close to unity in agreement with experiment.Comment: 33 pages, Latex with epsf, figures included, to appear in Phys. Rev.

Pion Excess, Nuclear Correlations, and the Interpretation of (p⃗,n⃗\vec p, \vec n) Spin Transfer Experiments

Conventional theories of nuclear interactions predict a net increase in the distribution of virtual pions in nuclei relative to free nucleons. Analysis of data from several nuclear experiments has led to claims of evidence against such a pion excess. These conclusions are usually based on a collective theory (RPA) of the pions, which may be inadequate. The issue is the energy dependence of the nuclear response, which differs for theories with strong NN correlations from the RPA predictions. In the present paper, information about the energy dependence is extracted from sum rules, which are calculated for such a correlated, noncollective nuclear theory. The results lead to much reduced sensitivity of nuclear reactions to the correlations that are responsible for the pion excess. The primary example is $(\vec p,\vec n)$ spin transfer, for which the expected effects are found to be smaller than the experimental uncertainties. The analysis has consequences for Deep Inelastic Scattering (DIS) experiments as well.Comment: 16 pages, LaTeX, no figures, submitted to Phys. Rev.

A Light Front Treatment of the Nucleus-Implications for Deep Inelastic Scattering

A light front treatment of the nuclear wave function is developed and applied, using the mean field approximation, to infinite nuclear matter. The nuclear mesons are shown to carry about a third of the nuclear plus momentum, p+; but their momentum distribution has support only at p+ =0, and the mesons do not contribute to nuclear deep inelastic scattering. This zero mode effect occurs because the meson fields are independent of space-time position.Comment: 11 pages, revtex, 1 figur

Nuclear Shadowing in a Parton Recombination Model

Deep inelastic structure functions $F_2^A(x)$ are investigated in a $Q^2$ rescaling model with parton recombination effects. We find that the model can explain experimentally measured $F_2^A(x)$ structure functions reasonably well in the wide Bjorken$-x$ range ($0.005<x<0.8$). In the very small $x$ region ($x<0.02$), recombination results are very sensitive to input sea-quark and gluon distributions.Comment: preprint MKPH-T-93-04, IU/NTC 92-20, 25 pages, TEX file (without Figs. 1-14)., (address after April 1: Saga U., Japan

Flavor and Charge Symmetry in the Parton Distributions of the Nucleon

Recent calculations of charge symmetry violation(CSV) in the valence quark distributions of the nucleon have revealed that the dominant symmetry breaking contribution comes from the mass associated with the spectator quark system.Assuming that the change in the spectator mass can be treated perturbatively, we derive a model independent expression for the shift in the parton distributions of the nucleon. This result is used to derive a relation between the charge and flavor asymmetric contributions to the valence quark distributions in the proton, and to calculate CSV contributions to the nucleon sea. The CSV contribution to the Gottfried sum rule is also estimated, and found to be small

Developing a framework for the analysis of power through depotentia

Stakeholder participation in tourism policy-making is usually perceived as providing a means of empowerment. However participatory processes drawing upon stakeholders from traditionally empowered backgrounds may provide the means of removing empowerment from stakeholders. Such an outcome would be in contradiction to the claims that participatory processes improve both inclusivity and sustainability. In order to form an understanding of the sources through which empowerment may be removed, an analytical perspective has been developed deriving from Lukes�s views of power dating from 1974. This perspective considers the concept of depotentia as the removal of �power to� without speculating upon the underlying intent and also provides for the multidimensionality of power to be examined within a single study. The application of this analytical perspective has been tested upon findings of the government-commissioned report of the Countryside and Community Research Unit in 2005. The survey and report investigated the progress of Local Access Forums in England created in response to the Countryside and Rights of Way Act 2000. Consideration of the data from this perspective permits the classification of individual sources of depotentia which can each be addressed and potentially enable stakeholder groups to reverse loss of empowerment where it has occurred