Effect of <i>Leptographium terebrantis</i> on Foliage, New Root Dynamics, and Stemwood Growth in a Loblolly Pine (<i>Pinus taeda</i> L.) Plantation

The course of the bark beetle-vectored fungus, Leptographium terebrantis S. J. Barras and T. J. Perry, in stemwood growth loss of declining pines in the southeastern United States was assessed in a 13-year-old loblolly pine (Pinus taeda L.) plantation near Eufaula, Alabama, U.S.A. Using stem inoculation as a surrogate for root infection, we hypothesized that L. terebrantis infection impairs sapwood function and thus limits the tree leaf area (AL), new root production, and stemwood growth. Sterile toothpicks colonized by L. terebrantis at varying inoculum densities was used to elicit host growth responses. In the third year after inoculation, the root pathogen reduced the foliage moisture content, whole-tree leaf area (AL), the ratio of AL to tree sapwood area (AS), and stemwood growth in trees receiving the high inoculation treatment relative to those receiving the low or medium inoculation treatments, or the wound or control treatments after seven months of water deficit. The absence of a similar response to water deficit among trees that were noninoculated, wounded, or inoculated at the low or medium densities suggests that, in the loblolly pine–L. terebrantis pathosystem at our study site, the physiological stress caused by water deficit and the high inoculum density was required for the pathogen to elicit a stemwood growth loss. Thus, in loblolly pine forests of the southeastern United States, where climate and soil conditions yield prolonged periods of physiological stress, the presence of L. terebrantis has the potential to reduce stand volume and widen the gap between the predicted and actual stemwood production

Effect of Leptographium terebrantis on Foliage, New Root Dynamics, and Stemwood Growth in a Loblolly Pine (Pinus taeda L.) Plantation

The course of the bark beetle-vectored fungus, Leptographium terebrantis S. J. Barras and T. J. Perry, in stemwood growth loss of declining pines in the southeastern United States was assessed in a 13-year-old loblolly pine (Pinus taeda L.) plantation near Eufaula, Alabama, U.S.A. Using stem inoculation as a surrogate for root infection, we hypothesized that L. terebrantis infection impairs sapwood function and thus limits the tree leaf area (AL), new root production, and stemwood growth. Sterile toothpicks colonized by L. terebrantis at varying inoculum densities was used to elicit host growth responses. In the third year after inoculation, the root pathogen reduced the foliage moisture content, whole-tree leaf area (AL), the ratio of AL to tree sapwood area (AS), and stemwood growth in trees receiving the high inoculation treatment relative to those receiving the low or medium inoculation treatments, or the wound or control treatments after seven months of water deficit. The absence of a similar response to water deficit among trees that were noninoculated, wounded, or inoculated at the low or medium densities suggests that, in the loblolly pine&ndash;L. terebrantis pathosystem at our study site, the physiological stress caused by water deficit and the high inoculum density was required for the pathogen to elicit a stemwood growth loss. Thus, in loblolly pine forests of the southeastern United States, where climate and soil conditions yield prolonged periods of physiological stress, the presence of L. terebrantis has the potential to reduce stand volume and widen the gap between the predicted and actual stemwood production

Functional model of water balance variability at the catchment scale: 1. Evidence of hydrologic similarity and space-time symmetry

This paper presents analysis of annual water balance variability, (1) regional (between-catchment) variability and (2) between-year (interannual) variability and the symmetry between the two. This involved analysis of the annual water balance in terms of a two-stage partitioning, first, of annual precipitation into quick flow and soil wetting and, subsequently, of the resulting soil wetting into slow flow and vaporization. The nature of this water balance partitioning is explored by completing the above analysis in 377 Model Parameter Estimation Experiment (MOPEX) catchments located across the continental United States. We fitted analytical functional relationships to the partitioning at each stage, producing expressions for the three components of quick flow, slow flow, and vaporization. They indicate that the heterogeneity of water balance partitioning among the MOPEX catchments is underlain by a universal relationship that is transferable regionally. Key nondimensional similarity parameters are identified that serve to connect this invariant regional relationship to site-specific response characteristics. These nondimensional formulations are extended to derive analytical expressions for several common metrics of annual water balance. The ability of the functional theory to predict regional patterns of mean annual water balance and interannual variability in individual catchments is assessed. Our analyses show a close symmetry between spatial (regional) variability of mean annual water balances and general trends of temporal (interannual) variability. The suggested functional theory can thus be the basis for data-based assessments of hydrologic similarity and used to assist with predictions of the effects of long-term climate variability and change, through providing a theoretical framework for “space for time” substitutions.Water ManagementCivil Engineering and Geoscience

A grant-based experiment to train clinical investigators: the AACR/ASCO methods in clinical cancer research workshop

To address the need for clinical investigators in oncology, AACR and ASCO established the Methods in Clinical Cancer Research Workshop (MCCRW). The workshop's objectives were to: (1) provide training in the methods, design, and conduct of clinical trials; (2) ensure that clinical trials met federal and international ethical guidelines; (3) evaluate the effectiveness of the workshop; and (4) create networking opportunities for young investigators with mentoring senior faculty. Educational methods included: (1) didactic lectures; (2) Small Group Discussion Sessions; (3) Protocol Development Groups; (4) one-on-one mentoring. Learning focused on the development of an IRB-ready protocol, which was submitted on the last day of the workshop. Evaluation methods included: (1) pre- and post-workshop tests; (2) students' workshop evaluations; (3) faculty's ratings of protocol development; (4) students' productivity in clinical research after the workshop; (5) an independent assessment of the workshop. From 1996-2014, 1932 students from diverse backgrounds attended the workshop. There was a significant improvement in the students' level of knowledge from the pre- to the post-workshop exams (p < 0.001). Across the classes, student evaluations were very favorable. At the end of the workshop, faculty rated 92-100% of the students' protocols as ready for IRB submission. Intermediate and long-term follow-ups indicated that more than 92% of students were actively involved in patientrelated research, and 66% had implemented five or more protocols. This NCI-sponsored MCCRW has had a major impact on the training of clinicians in their ability to design and implement clinical trials in cancer research