Mirror Symmetry and Other Miracles in Superstring Theory

The dominance of string theory in the research landscape of quantum gravity physics (despite any direct experimental evidence) can, I think, be justified in a variety of ways. Here I focus on an argument from mathematical fertility, broadly similar to Hilary Putnam's 'no miracles argument' that, I argue, many string theorists in fact espouse. String theory leads to many surprising, useful, and well-confirmed mathematical 'predictions' - here I focus on mirror symmetry. These predictions are made on the basis of general physical principles entering into string theory. The success of the mathematical predictions are then seen as evidence for framework that generated them. I attempt to defend this argument, but there are nonetheless some serious objections to be faced. These objections can only be evaded at a high (philosophical) price.Comment: For submission to a Foundations of Physics special issue on "Forty Years Of String Theory: Reflecting On the Foundations" (edited by G. `t Hooft, E. Verlinde, D. Dieks and S. de Haro)

Genetic drivers of kidney defects in the digeorge syndrome

BACKGROUND The DiGeorge syndrome, the most common of the microdeletion syndromes, affects multiple organs, including the heart, the nervous system, and the kidney. It is caused by deletions on chromosome 22q11.2; the genetic driver of the kidney defects is unknown. METHODS We conducted a genomewide search for structural variants in two cohorts: 2080 patients with congenital kidney and urinary tract anomalies and 22,094 controls. We performed exome and targeted resequencing in samples obtained from 586 additional patients with congenital kidney anomalies. We also carried out functional studies using zebrafish and mice. RESULTS We identified heterozygous deletions of 22q11.2 in 1.1% of the patients with congenital kidney anomalies and in 0.01% of population controls (odds ratio, 81.5; P = 4.5×1014). We localized the main drivers of renal disease in the DiGeorge syndrome to a 370-kb region containing nine genes. In zebrafish embryos, an induced loss of function in snap29, aifm3, and crkl resulted in renal defects; the loss of crkl alone was sufficient to induce defects. Five of 586 patients with congenital urinary anomalies had newly identified, heterozygous protein-Altering variants, including a premature termination codon, in CRKL. The inactivation of Crkl in the mouse model induced developmental defects similar to those observed in patients with congenital urinary anomalies. CONCLUSIONS We identified a recurrent 370-kb deletion at the 22q11.2 locus as a driver of kidney defects in the DiGeorge syndrome and in sporadic congenital kidney and urinary tract anomalies. Of the nine genes at this locus, SNAP29, AIFM3, and CRKL appear to be critical to the phenotype, with haploinsufficiency of CRKL emerging as the main genetic driver

Reading, metacognition, and motivation: A follow-up study of German students in Grades 7 and 8

This follow-up study to van Kraayenoord and Schneider (1999) examined the performance in reading, metacognition and motivation related to reading of students in Grades 7 and 8. Results showed significant correlations between all of the variables. A multivariate analysis of variance showed that good and poor readers differed in reading self-concept and metacognitive measures related to reading and memory. A stepwise regression analysis suggested that the metacognitive variables were the best predictors of reading. Furthermore, a comparison of the results of the previous study with those of the current investigation revealed that the findings were stable over time. Since the period between the two studies is the time during which students make important decisions related to enrolment in one of three distinct school-types in Germany, we examined the results of various groups of students: those in Gymnasium (high educational track), Realschule (middle educational track), and Hauptschule (low educational track). Students in the Gymnasium scored significantly better than students in the other two groups on almost all variables related to reading. A re-analysis of the data from our first investigation found that the results of the Gymnasium students in the second study could be predicted from their results obtained during elementary school

Low- and Lower Middle-Income Countries Advanced Practice Nurses: An Integrative Review

Aim: To review published literature descriptions of advanced practice nurses’ roles in low- and lower middle-income countries. Background: Advanced practice nurse roles have the potential to address insufficient healthcare resources in low- and lower middle-income countries. Introduction: This integrative review highlights advanced practice nurses’ roles in the delivery of healthcare services in low- and lower middle-income countries. Methods: Three electronic databases PubMed, CINAHL complete and ProQuest Health & Medicine were searched. No limits by year or language were set. The names for low- and lower middle-income countries and combinations ‘related to advanced practice nurses’ titles were used to identify papers. In addition, a review of publication type was performed. Themes found within the publications were assessed against the advanced practice nurses’ International Council of Nurses’ characteristics. An integrative review facilitated an appraisal of the papers identified. Results: The initial search identified 5778 publications in 16 languages. This number was reduced to 23, from 18 low- and lower middle-income once exclusion criteria were applied. Six publications were from 1977 to 1999, and six between 2000 and 2010, with the remaining 11 from 2011 to 2018. Zambia had the most publications. Notably, 63 countries were not represented. Of those meeting inclusion criteria, the majority addressed education with a lesser extent focusing on practice and regulation of advanced practice nurse’s roles. The majority were published during the last decade. Discussion: This review of the published literature identified advanced practice nurses’ roles and function within some healthcare systems. However, not all components were reported. Examination of the grey literature could provide additional information about the actual and potential benefits of advanced practice nurses’ in low- and lower middle-income countries. Conclusion: The published literature that referred to advanced practice nurses’ identified their contribution to positive impacts on health care over the last 40 years. However, with only 11 publications identified in the last 7 years, further review is required to understand the advanced practice nurses’ roles in these countries. Implications for nursing and/or health policy: Further development of advanced practice nurses’ in low- and lower middle-income countries is supported by the lack of published literature