Vegetative development of inbred and hybrid maize

The study herein reported consists of observations on the vegetative development of maize with special emphasis on leaf production. The objective has been to obtain a better picture of the dynamics of hybrid vigor as expressed through growth processes such as rate, correlation, sequence and final size. Most of the results were obtained from two Iowa inbred strains and their reciprocal hybrids, and for that reason may not be entirely characteristic of a general population. Specific researches on growth and heterosis of maize are so numerous as to prohibit any but general comment. Orthodox explanations of hybrid vigor or heterosis have drawn heavily on the theories of inheritance. Shull (23) was long the proponent of a hypothesis which suggested that the diversity of the parental elements brought together in some way stimulated growth and development in the offspring. Later, Jones (10, 11) developed a concept in which the increased vigor of a hybrid was attributed to the greater number of active, favorable hereditary characters it possessed, the combined contributions of both parents being greater than that possessed by either parent alone. Rasmusson (18) offered the interaction hypothesis in which the combined action of the hereditary factors, as well as the sum of their, individual actions, plays a part in any expression of heterosis. Finally, there should be considered the experiments of Sveschnikova on hybrids of Vicia (24). As opposed to the ordinary concept of hybrid vigor, this author presents instances in which decreased vigor was obtained in crosses between very similar forms of the same species

Reading Critically from the Archives: James Merrill Linn’s Diary as a Gateway to the Past

Archival research and reading from the archives have long been embraced as a scholarly research practice in humanities disciplines. While scholars may spend weeks or months poring over hidden treasures found in archives, undergraduate students are often not exposed to these materials in a hands-on way. However, college and university libraries often have archival collections tucked away that can facilitate learning when used in thoughtfully crafted assignments. In this chapter, we discuss how we used Text Encoding Initiative (TEI) and archival materials to provide students with an opportunity to engage in a close and critical reading of excerpts from the Civil War era diary of James Merrill Linn

Current perspectives on prevention of vascular cognitive impairment and promotion of vascular brain health

\ua9 2023 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group. Introduction: The true global burden of vascular cognitive impairment (VCI) is unknown. Reducing risk factors for stroke and cardiovascular disease would inevitably curtail VCI. Areas Covered: The authors review current diagnosis, epidemiology, and risk factors for VCI. VCI increases in older age and by inheritance of known genetic traits. They emphasize modifiable risk factors identified by the 2020 Lancet Dementia Commission. The most profound risks for VCI also include lower education, cardiometabolic factors, and compromised cognitive reserve. Finally, they discuss pharmacological and non-pharmacological interventions. Expert Opinion: By virtue of the high frequencies of stroke and cardiovascular disease the global prevalence of VCI is expectedly higher than prevalent neurodegenerative disorders causing dementia. Since ~ 90% of the global burden of stroke can be attributed to modifiable risk factors, a formidable opportunity arises to reduce the burden of not only stroke but VCI outcomes including progression from mild to the major in form of vascular dementia. Strict control of vascular risk factors and secondary prevention of cerebrovascular disease via pharmacological interventions will impact on burden of VCI. Non-pharmacological measures by adopting healthy diets and encouraging physical and cognitive activities and urging multidomain approaches are important for prevention of VCI and preservation of vascular brain health

Bridging Communities of Practice: Cross-Institutional Collaboration for Undergraduate Digital Scholars

At Bucknell University and Gettysburg College, an increasing focus on supporting creative undergraduate research as intensive, high-impact experiences has resulted in both institutions implementing library-led digital scholarship fellowships for their students. Gettysburg’s Digital Scholarship Summer Fellowship began in 2016, and Bucknell’s Digital Scholarship Summer Research Fellowship in 2017. While academic libraries have emerged as leaders on college campuses for digital humanities (DH) services, the programs at Gettysburg and Bucknell are distinctive in their structured curricula, a focus on independent student research, and the development of a local community of practice. In this chapter, we explore the development of cross-institutional communities of practice grounded in the digital humanities, and the ways in which we brought students in our two programs together

Dementia Prevalence Estimates in Sub-Saharan Africa: Comparison of two Diagnostic Criteria.

We have previously reported the prevalence of dementia in older adults living in the rural Hai district of Tanzania according to the Diagnostic and Statistical Manual of Mental Disorders, 4th edition (DSM-IV) criteria. The aim of this study was to compare prevalence rates using the DSM-IV criteria with those obtained using the 10/66 diagnostic criteria, which is specifically designed for use in low- and middle-income countries. In phase I, 1,198 people aged 70 and older were screened for dementia. A stratified sample of 296 was then clinically assessed for dementia according to the DSM-IV criteria. In addition, data were collected according to the protocol of the 10/66 Dementia Research Group, which allowed a separate diagnosis of dementia according to these criteria to be established. The age-standardised prevalence of clinical DSM-IV dementia was 6.4% (95% confidence interval [CI] 4.9-7.9%) and of '10/66 dementia' was 21.6% (95% CI 17.5-25.7%). Education was a significant predictor of '10/66 dementia', but not of DSM-IV dementia. There are large discrepancies in dementia prevalence rates depending on which diagnostic system is used. In rural sub-Saharan Africa, it is not clear whether the association between education and dementia using the 10/66 criteria is a genuine effect or the result of an educational bias within the diagnostic instrument. Despite its possible flaws, the DSM-IV criteria represent an international standard for dementia diagnosis. The 10/66 diagnostic criteria may be more appropriate when identification of early and mild cognitive impairment is required

Improving on whole-brain radiotherapy in patients with large brain metastases: a planning study to support the AROMA clinical trial

PURPOSE: To develop a novel dose-escalated volumetric modulated arc therapy (VMAT) strategy for patients with single or multiple large brain metastases which can deliver a higher dose to individual lesions for better local control (LC), and to compare dosimetry between whole brain radiotherapy (WBRT), hippocampal-sparing whole brain radiotherapy (HS-WBRT) and different VMAT-based focal radiotherapy approaches. METHODS AND MATERIALS: We identified 20 patients with one to ten brain metastases and at least one lesion larger than 15 cm3 who had received WBRT as part of routine care. For each patient, we designed and evaluated five radiotherapy treatment plans, including WBRT, HS-WBRT and three VMAT dosing models. A dose of 20 Gy in 5 fractions was prescribed to the whole brain or target volumes depending on the plan, with higher doses to smaller lesions and dose-escalated inner planning target volumes (DE-iPTV) in VMAT plans, respectively. Treatment plans were evaluated using the efficiency index, mean dose and D0.1cc to the target volumes and organs at risk. RESULTS: Compared with WBRT, VMAT plans achieved a significantly more efficient dose distribution in brain lesions, especially with our DE-iPTV model, while minimising the dose to the normal brain and other organs at risks (OARs) (p < 0.05). CONCLUSIONS: VMAT plans obtained higher doses to brain metastases and minimised doses to OARs. Dose-escalated VMAT for larger lesions allows higher radiotherapy doses to be delivered to larger lesions while maintaining safe doses to OARs

The impact of unscheduled gaps and iso-centre sequencing on the biologically effective dose in Gamma Knife radiosurgery.

PURPOSE: Establish the impact of iso-centre sequencing and unscheduled gaps in Gamma Knife® (GK) radiosurgery on the biologically effective dose (BED). METHODS: A BED model was used to study BED values on the prescription iso-surface of patients treated with GK Perfexion™ (Vestibular Schwannoma). The effect of a 15 min gap, simulated at varying points in the treatment delivery, and adjustments to the sequencing of iso-centre delivery, based on average dose-rate, was quantified in terms of the impact on BED. RESULTS: Depending on the position of the gap and the average dose-rate profiles, the mean BED values were decreased by 0.1% to 9.9% of the value in the original plan. A heuristic approach to iso-centre sequencing showed variations in BED of up to 14.2%, relative to the mean BED of the original sequence. CONCLUSIONS: The treatment variables, like the iso-centre sequence and unscheduled gaps, should be considered during GK radiosurgery treatments

A New Approach for Developing "Implementation Plans" for Cognitive Stimulation Therapy (CST) in Low and Middle-Income Countries: Results From the CST-International Study

Background: Even with a strong evidence base, many healthcare interventions fail to be translated to clinical practice due to the absence of robust implementation strategies. For disorders such as Alzheimer's disease and other dementias, access to evidence-based interventions beyond research settings is of great importance. Cognitive Stimulation Therapy (CST) is a brief, group-based intervention, with consistent evidence of effectiveness. / Methods: An implementation focused, three-phase methodology was developed using extensive stakeholder engagement. The methods resulted in a standardized Implementation Plan for the successful translation of CST from research to practice. The methodology was developed using the Consolidated Framework for Implementation Research (CFIR) and refined in three countries that vary in levels of economic development and healthcare systems (Brazil, India and Tanzania). / Results: Five Implemention Plans for CST were produced. Each plan contained implementation strategies and action plans devised in conjunction with policy professionals, healthcare professionals, people with dementia and family carers, and an international team of researchers and clinicians. / Conclusion: This novel methodology can act as a template for implementation studies in diverse healthcare systems across the world. It is an effective means of devising socio-culturally informed Implementation Plans that account for economic realities, health equity and healthcare access