Imperfect Construction of Microclusters

Microclusters are the basic building blocks used to construct cluster states capable of supporting fault-tolerant quantum computation. In this paper, we explore the consequences of errors on microcluster construction using two error models. To quantify the effect of the errors we calculate the fidelity of the constructed microclusters and the fidelity with which two such microclusters can be fused together. Such simulations are vital for gauging the capability of an experimental system to achieve fault tolerance.Comment: 5 pages 2 figure

Stunting: past, present, future

Child malnutrition is a very important global health challenge. 155 million children globally suffer from malnutrition and are consequently stunted, much shorter than healthy children at the same age. Reducing stunting was an important target in the Millenium Development Goals and is also a target under Goal 2 of the Sustainable Development Goals. This report summarises recent research on child stunting that was presented and discussed at a conference, STUNTING: PAST, PRESENT AND FUTURE, at the London School of Economics and Political Science in September 2017. The conference brought together academics across a wide range of disciplines with policy experts and influencers from the third sector. There were four key lessons that participants took away from the conference. First, stunting was present in currently developed countries at the beginning of the twentieth century, which suggests that reductions in stunting were a corollary to the secular increase in mean adult height across the twentieth century. Second, there needs to be more research on catchup growth in adolescence to determine whether catch-up growth in height is also associated with improvements in other dimensions of health and human capital that are affected by malnutrition, for instance cognitive deficiencies. If interventions in adolescence can be effective, then it may be possible to mitigate some of the consequences of stunting for already stunted children. Third, researchers need to be aware of the large degree of spatial variation in stunting within countries and the distinct age pattern of stunting between ages 0 and 5 when trying to understand why children become stunted. Fourth, participants agreed that more interdisciplinary collaboration is necessary to design experiments and models to capture the multi-dimensional nature of child stunting

Sample selection biases and the historical growth pattern of children

Bodenhorn et al. (2017) have recently sparked considerable controversy by arguing that the fall in adult stature observed in military samples in the United States and Britain during industrialisation was a figment of sample selection bias. While subsequent papers have questioned the extent of the bias (Komlos and A’Hearn 2016; Zimran 2017), there is renewed concern about selection bias in historical anthropometric datasets. This paper extends Bodenhorn et al.’s discussion of selection bias on unobservables to sources of children’s growth, specifically focussing on biases that could distort the age pattern of growth. Understanding how the growth pattern of children has changed is important since these changes underpinned the secular increase in adult stature and are related to child stunting observed in developing countries today. However, there is potential for selection on unobservables in historical datasets containing children’s and adolescents’ height, so scholars must be aware of these biases before analysing these sources. This paper highlights, among others, three common sources of bias: 1) positive selection of children into secondary school in the late nineteenth and early twentieth centuries; 2) distorted height by age profiles created by age thresholds for enlistment in the military; and 3) changing institutional ecology which determines to which institutions children are sent. Accounting for these biases weakens the evidence of a strong pubertal growth spurt in the nineteenth century and raises doubts on some long run analyses of changes in children’s growth, especially for Japan

The effect of nutritional status on historical infectious disease morbidity: evidence from the London Foundling Hospital, 1892-1919

There is a complex inter-relationship between nutrition and morbidity in human health. Many diseases reduce nutritional status, but on the other hand, having low nutritional status is also known to make individuals more susceptible to certain diseases and to more serious illness. Modern evidence on these relationships, determined after the introduction of antibiotics and vaccines, may not be applicable to historical settings before these medical technologies were available. This paper uses a historical cohort study based on records from the London Foundling Hospital to determine the causal effect of nutritional status of children, proxied by weight- and height-for-age Z-scores, on the odds of contracting five infectious diseases of childhood (measles, mumps, rubella, chicken pox and whooping cough) and on sickness duration from these diseases. I identify a causal effect by exploiting the randomisation of environmental conditions as foundling children were removed from their original homes, then fostered with families in counties nearby London and later returned to the Foundling Hospital’s main site in London. I find no effect of nutritional status on the odds of contracting the five diseases, but I do find a historically important and statistically significant effect of nutritional status on sickness duration for measles and mumps. These findings have three implications. First, historical incidence of these diseases was unrelated to nutritional status, meaning that poor nutritional status during famines or during the Colombian Exchange did not affect the spread of epidemics. However, undernutrition in these events may have exacerbated measles severity. Second, improving nutritional status in the past 150 years would have reduced the severity of measles and mumps infections but not affect the decline in whooping cough mortality. Finally, selective culling effects from measles would be larger than those from whooping cough since whooping cough severity was not correlated with underlying nutritional status

Synthesis and Characterization of a Trypsin Inhibitor

Inhibitors of biological enzymes are frequently produced by mimicking the molecular structure of the enzyme\u27s natural substrate. Because of the extensive studies that have already been performed on the trypsin enzyme, its natural substrates and its mode of interaction with them are well understood. By finding an easily synthesized molecule to inhibit the trypsin enzyme, college level laboratory experiments could be designed and integrated into organic chemistry and biochemistry courses. In this project, a possible trypsin inhibitor molecule, 4-fluorobenzylaimine, was chosen based on its similarity to the natural trypsin substrates and because it has been predicted through computational studies to be a potential trypsin inhibiotr. 4-fluorobenzylaimine was synthesized and tested for inhibition using Michaelis-Menten kinetics. The inhibition constant, Ki, determined experimentally for a standard 4-fluorobenzylaimine was found to be 0.65 mM, which compared closely to the Ki calculated by Kurinov and Harrison. However, the Ki determined experimentally for the synthesized 4-fluorobenzylaimine was found to be 3.2 mM