An Analysis of the Field Experience with the Florida Division of Health

The seven-week field experience was designed to increase the student\u27s understanding of public health. She was also to develop her awareness of factors which affect public health program planning and the coordination of the roles of the public health nutritionist with the roles of other health workers. These objectives were achieved through observation and participation in the program of the Nutrition Section of the Florida Division of Health. A review of environmental influences, health-related statistics, and the existing administrative structures of the Division of Health and the Nutrition Section was related to health program planning. The professional characteristics of the public health nutritionist were assessed and applied to the functional aspects of administration, consultation, and instruction. A project in in-service education for public health nurses is discussed, and its impact on the participants evaluated. A principle of the public health philosophy described perceives the public health nutritionist as a specialized health professional with responsibility for leadership in achieving and maintaining adequate nutritional status. The influences of community cooperation on program planning and of coordination with other health workers on the role of the public health nutritionist is discussed

Service as a Strategy: Combating Youth Unemployment

"Youth Engaged in Service: A Strategy for Combating Youth Unemployment," was written to promote youth service programs as a complimentary initiative in reducing rising levels of global unemployment. It contends that with higher numbers of young people becoming better educated and more enlightened than ever before, the absence of constructive alternatives may leave the youth experiencing "a sense of vulnerability, uselessness and idleness." The paper places emphasis on the need to provide young people with structured opportunities in which they apply their talents and abilities, while developing skills and habits that transfer to economic viability. Therefore, it examines how youth service programs can provide a valuable addition to traditional youth employment strategies

Study of Robinson Jeffers' Adaptation of Euripides' Medea

Englis

Tree water uptake patterns across the globe.

Plant water uptake from the soil is a crucial element of the global hydrological cycle and essential for vegetation drought resilience. Yet, knowledge of how the distribution of water uptake depth (WUD) varies across species, climates, and seasons is scarce relative to our knowledge of aboveground plant functions. With a global literature review, we found that average WUD varied more among biomes than plant functional types (i.e. deciduous/evergreen broadleaves and conifers), illustrating the importance of the hydroclimate, especially precipitation seasonality, on WUD. By combining records of rooting depth with WUD, we observed a consistently deeper maximum rooting depth than WUD with the largest differences in arid regions - indicating that deep taproots act as lifelines while not contributing to the majority of water uptake. The most ubiquitous observation across the literature was that woody plants switch water sources to soil layers with the highest water availability within short timescales. Hence, seasonal shifts to deep soil layers occur across the globe when shallow soils are drying out, allowing continued transpiration and hydraulic safety. While there are still significant gaps in our understanding of WUD, the consistency across global ecosystems allows integration of existing knowledge into the next generation of vegetation process models

Manipulative experiments demonstrate how long-term soil moisture changes alter controls of plant water use

Tree transpiration depends on biotic and abiotic factors that might change in the future, including precipitation and soil moisture status. Although short-term sap flux responses to soil moisture and evaporative demand have been the subject of attention before, the relative sensitivity of sap flux to these two factors under long-term changes in soil moisture conditions has rarely been determined experimentally. We tested how long-term artificial change in soil moisture affects the sensitivity of tree-level sap flux to daily atmospheric vapor pressure deficit (VPD) and soil moisture variations, and the generality of these effects across forest types and environments using four manipulative sites in mature forests. Exposure to relatively long-term (two to six years) soil moisture reduction decreases tree sap flux sensitivity to daily VPD and relative extractable water (REW) variations, leading to lower sap flux even under high soil moisture and optimal VPD. Inversely, trees subjected to long-term irrigation showed a significant increase in their sensitivity to daily VPD and REW, but only at the most water-limited site. The ratio between the relative change in soil moisture manipulation and the relative change in sap flux sensitivity to VPD and REW variations was similar across sites suggesting common adjustment mechanisms to long-term soil moisture status across environments for evergreen tree species. Overall, our results show that long-term changes in soil water availability, and subsequent adjustments to these novel conditions, could play a critical and increasingly important role in controlling forest water use in the future.Peer reviewe

Hydraulic architecture explains species moisture dependency but not mortality rates across a tropical rainfall gradient

Intensified droughts are affecting tropical forests across the globe. However, the underlying mechanisms of tree drought response and mortality are poorly understood. Hydraulic traits and especially hydraulic safety margins (HSMs), that is, the extent to which plants buffer themselves from thresholds of water stress, provide insights into species-specific drought vulnerability. We investigated hydraulic traits during an intense drought triggered by the 2015–2016 El Niño on 27 canopy tree species across three tropical forest sites with differing precipitation. We capitalized on the drought event as a time when plant water status might approach or exceed thresholds of water stress. We investigated the degree to which these traits varied across the rainfall gradient, as well as relationships among hydraulic traits and species-specific optimal moisture and mortality rates. There were no differences among sites for any measured trait. There was strong coordination among traits, with a network analysis revealing two major groups of coordinated traits. In one group, there were water potentials, turgor loss point, sapwood capacitance and density, HSMs, and mortality rate. In the second group, there was leaf mass per area, leaf dry matter content, hydraulic architecture (leaf area to sapwood area ratio), and species-specific optimal moisture. These results demonstrated that while species with greater safety from turgor loss had lower mortality rates, hydraulic architecture was the only trait that explained species’ moisture dependency. Species with a greater leaf area to sapwood area ratio were associated with drier sites and reduced their transpirational demand during the dry season via deciduousness

Reductions in tree performance during hotter droughts are mitigated by shifts in nitrogen cycling

Climate warming should result in hotter droughts of unprecedented severity in this century. Such droughts have been linked with massive tree mortality, and data suggest that warming interacts with drought to aggravate plant performance. Yet how forests will respond to hotter droughts remains unclear, as does the suite of mechanisms trees use to deal with hot droughts. We used an ecosystem‐scale manipulation of precipitation and temperature on piñon pine (Pinus edulis) and juniper (Juniperus monosperma) trees to investigate nitrogen (N) cycling‐induced mitigation processes related to hotter droughts. We found that while negative impacts on plant carbon and water balance are manifest after prolonged drought, performance reductions were not amplified by warmer temperatures. Rather, increased temperatures for 5 years stimulated soil N cycling under piñon trees and modified tree N allocation for both species, resulting in mitigation of hotter drought impacts on tree water and carbon functions. These findings suggest that adjustments in N cycling are likely after multi‐year warming conditions and that such changes may buffer reductions in tree performance during hotter droughts. The results highlight our incomplete understanding of trees' ability to acclimate to climate change, raising fundamental questions about the resistance potential of forests to long‐term, compound climatic stresses.Pacific Northwest National Laboratories; Swiss Federal Research Institute; Swiss Forest Lab; Swiss National Science Foundation SNF, Grant/Award Number: 31003A_159866; U.S. Geological Survey; U.S. Department of Energy Office of Science, Grant/Award Number: DESC‐0008168; Spanish Government, Grant/Award Number: CGL2015‐69773‐C2‐2‐P; Generalitat Valenciana, Grant/Award Number: BEST/2016/289; Los Alamos National Laboratory

No carbon storage in growth-limited trees in a semi-arid woodland

© The Author(s) 2023. This article is licensed under a Creative Commons Attribution 4.0 International License.Plant survival depends on a balance between carbon supply and demand. When carbon supply becomes limited, plants buffer demand by using stored carbohydrates (sugar and starch). During drought, NSCs (non-structural carbohydrates) may accumulate if growth stops before photosynthesis. This expectation is pervasive, yet few studies have combined simultaneous measurements of drought, photosynthesis, growth, and carbon storage to test this. Using a field experiment with mature trees in a semi-arid woodland, we show that growth and photosynthesis slow in parallel as ψpd declines, preventing carbon storage in two species of conifer (J. monosperma and P. edulis). During experimental drought, growth and photosynthesis were frequently co-limited. Our results point to an alternative perspective on how plants use carbon that views growth and photosynthesis as independent processes both regulated by water availability.The Los Alamos Survival-Mortality Experiment (SUMO) was funded by the US Department of Energy, Office of Science, Biological and Environmental Research. R.A.T., A.M.T., and H.D.A. were supported by the NSF Division of Integrative Organismal Systems, Integrative Ecological Physiology Program (IOS-1755345, IOS-1755346). R.A.T. was also supported by the NSF Graduate Research Fellowship Program. H.D.A. was also supported by the USDA National Institute of Food and Agriculture (NIFA), McIntire Stennis Project 1019284 and Agriculture and Food Research Initiative award 2021-67013-33716. C.G. was supported by the Swiss National Science Foundation (310030_204697).Peer reviewe