Responses of sap velocity in Acacia mellifera trees to soil water availability, vapour pressure deficit and global radiation

Acacia mellifera (multi-stem deciduous tree) is one of the dominant woody species responsible for bush encroachment in southern African savannahs. However, very little is known on water use, transpiration or xylem sap flow of A. mellifera. We analyzed the responses of sap velocity in A. mellifera to soil moisture, vapour pressure deficit and global radiation. This knowledge is necessary to improve hydrological modelling and will as such contribute to our understanding of the impacts of bush encroachment in (semi) arid savannahs on the soil water balance. We monitored sap velocities at two sites that differed in tree density in a semi-arid thornbush savannah in central Namibia (mean annual precipitation = 346 mm). Sap velocities were derived using the Heat Ratio Method. Measurements were done in four periods of 3-4 months between November 2014 and September 2016. The measurement periods covered the transitions between the dry and rainy season and vice versa, and the dry season. In two of these periods we did measurements at all stems of three trees per site (a total of 17-19 stems), while in the other two periods sap velocities were measured on one stem per tree for six to eight trees per site. Preliminary results indicate that the day-to-day fluctuations in cumulative daily sap velocity showed a three-phase interaction with soil water tension (minimum soil water tension of four sensors to 1-m depth). Phase I: At soil water tension < ~ pF 2.5, soil water tension had little influence on sap velocities, and fluctuations in sapflow seemed to be related to VPD and global radiation. Phase II: At soil water tensions between ~ pF 2.5 and ~ pF 3.2, sap velocities were negatively related to soil water tension. Phase III: At soil water tensions > ~ pF 3.2 no sap flow could be detected. The study was done in the framework of SASSCAL (Southern African Science Service Centre for Climate Change and Adaptive Land Management) granted by the German Federal Ministry of Education and Research (BMBF)

PNN Monitor: International Scholarship PhD Candidates

This report presents the first detailed study examining the working and living conditions of international scholarship PhD candidates (ISPCs) in the Netherlands. The Netherlands has several PhD trajectories, which differ from one another in terms of funding and the candidate’s employment status at the relevant institution. Approximately 3800 international PhD candidates receive a scholarship instead of a salary. While these candidates do similar work to employed PhD candidates, their financial compensation and employment benefits are considerably different. Public data on the working conditions, experiences, and problems of international scholarship PhD candidates is scarce. To better understand the challenges and needs of this group, Promovendi Netwerk Nederland (PNN) conducted a survey between 20 March and 15 May 2023. PNN obtained data from 250 international scholarship PhD candidates in the Netherlands, approximately 7% of the total population of ISPCs. The working conditions and experiences of ISPCs and their supervisors have been on the radar of The Young Academy [De Jonge Akademie] for many years as well. This report also presents the results of a survey that The Young Academy conducted between June and October 2018 focusing on the same group of PhD candidates and their supervisors. The main findings of the PNN survey show an urgent need for fundamental restructuring to ensure fair employment conditions guaranteeing fair living and working conditions for all ISPCs in the Netherlands. Given the precarious situation of these candidates, however, PNN also makes several short-term recommendations for immediate action based on the findings presented in this report

Needs, problems and rehabilitation goals of young children with cerebral palsy as formulated in the rehabilitation activities profile for children

Objective: To describe the content of needs, problems and goals of 41 Dutch children with cerebral palsy using the International Classification of Functioning, Disability and Health for Children and Youth (ICF-CY) as a classification system. To evaluate the adherence of formulations of needs, problems and goals to specifications of the Rehabilitation Activities Profile for Children. Methods: Raw text data were extracted and organized. Two raters independently weighed the entries' quality against the specifications and linked the extracted content to ICF-CY categories. Results: In 12% of the reports no needs, and in 24% no principal goals, were formulated. Needs mostly pertained to the activities-and-participation domain (65%), whereas problems and goals covered all 3 ICF-CY domains. None of the needs were prioritized and 79% met the quality criterion of description of a problem/desire. Twenty-four percent of the problems were described in the activity-and-participation domain and 83% referred to a treatable problem. Fifty-six percent of the goals were formulated in terms of intended result/effect and 63% as child/parent actions. Conclusion: Insight is provided into the content of rehabilitation programmes for children with cerebral palsy. To optimize the quality of the reports, research on reasons for non-adherence to specifications of the Rehabilitation Activities Profile is needed

Characteristics of chronic non-specific musculoskeletal pain in children and adolescents attending a rheumatology outpatients clinic: a cross-sectional study

Background: Chronic non-specific musculoskeletal pain (CNSMSP) may develop in childhood and adolescence, leading to disability and reduced quality of life that continues into adulthood. The purpose of the study was to build a biopsychosocial profile of children and adolescents with CNSMSP. Methods: CNSMSP subjects (n = 30, 18 females, age 7-18) were compared with age matched pain free controls across a number of biopsychosocial domains. Results: In the psychosocial domain CNSMSP subjects had increased levels of anxiety and depression, and had more somatic pain complaints. In the lifestyle domain CNSMSP subjects had lower physical activity levels, but no difference in television or computer use compared to pain free subjects. Physically, CNSMSP subjects tended to sit with a more slumped spinal posture, had reduced back muscle endurance, increased presence of joint hypermobility and poorer gross motor skills. Conclusion: These findings support the notion that CNSMSP is a multidimensional biopsychosocial disorder. Further research is needed to increase understanding of how the psychosocial, lifestyle and physical factors develop and interact in CNSMSP