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Patients with posttraumatic stress disorder (PTSD) exhibit smaller regional brain volumes in commonly reported regions including the amygdala and hippocampus, regions associated with fear and memory processing. In the current study, we have conducted a voxel-based morphometry (VBM) meta-analysis using whole-brain statistical maps with neuroimaging data from the ENIGMA-PGC PTSD working group.
Methods
T1-weighted structural neuroimaging scans from 36 cohorts (PTSD n = 1309; controls n = 2198) were processed using a standardized VBM pipeline (ENIGMA-VBM tool). We meta-analyzed the resulting statistical maps for voxel-wise differences in gray matter (GM) and white matter (WM) volumes between PTSD patients and controls, performed subgroup analyses considering the trauma exposure of the controls, and examined associations between regional brain volumes and clinical variables including PTSD (CAPS-4/5, PCL-5) and depression severity (BDI-II, PHQ-9).
Results
PTSD patients exhibited smaller GM volumes across the frontal and temporal lobes, and cerebellum, with the most significant effect in the left cerebellum (Hedges’ g = 0.22, pcorrected = .001), and smaller cerebellar WM volume (peak Hedges’ g = 0.14, pcorrected = .008). We observed similar regional differences when comparing patients to trauma-exposed controls, suggesting these structural abnormalities may be specific to PTSD. Regression analyses revealed PTSD severity was negatively associated with GM volumes within the cerebellum (pcorrected = .003), while depression severity was negatively associated with GM volumes within the cerebellum and superior frontal gyrus in patients (pcorrected = .001).
Conclusions
PTSD patients exhibited widespread, regional differences in brain volumes where greater regional deficits appeared to reflect more severe symptoms. Our findings add to the growing literature implicating the cerebellum in PTSD psychopathology.
To examine the influence of prenatal artificial sweetener (AS) consumption on birth outcomes.
Design:
Systematic review and meta-analysis.
Setting:
Online databases (Medline, CINAHL, Embase, Cochrane Library, Scopus, Web of Science, FSTA – the food resource database, and ClinicalTrials.gov) were searched up to 9 April 2020. Studies of all designs (except case studies and reviews) were eligible, which contained information on the relevant population (pregnant women), intervention/exposure (any AS consumption), comparator (no AS consumption) and birth outcomes (preterm delivery, gestational age, birth weight).
Results:
From 677 citations, ten cohort studies and one randomised controlled trial (n 138 007 women) were included. ‘Low’ to ‘very low’ certainty evidence revealed that daily consumption of AS was associated with an increased risk of preterm delivery (three studies, n 129 009; risk ratio = 1·18, 95 % CI 1·09, 1·28, I2 = 9 %), a 24 g increase in birth weight (three studies, n 64 417; mean difference (MD): 23·74 g, 95 % CI 0·89, 45·58, I2 = 0 %) and a 0·11 week decrease in gestational age (three studies, n 64 417; MD: –0·11 weeks, 95 % CI –0·19, –0·03, I2 = 0 %).
Conclusions:
‘Low’ to ‘very low’ certainty evidence suggests daily AS consumption during pregnancy is associated with an increased risk of preterm delivery, increased birth weight and decreased gestational age. Additional ‘high’-quality research is urgently needed to further assess these relationships.
Two-step, solar-driven thermochemical fuel production offers the potential of efficient conversion of solar energy into dispatchable chemical fuel. Success relies on the availability of materials that readily undergo redox reactions in response to changes in environmental conditions. Those with a low enthalpy of reduction can typically be reduced at moderate temperatures, important for practical operation. However, easy reducibility has often been accompanied by surprisingly poor fuel production kinetics. Using the La1−xSrxMnO3 series of perovskites as an example, we show that poor fuel production rates are a direct consequence of the diminished enthalpy. Thus, material development efforts will need to balance the countering thermodynamic influences of reduction enthalpy on fuel production capacity and fuel production rate.
In the foothills of the Cumberland Mountains, in central Appalachia (a region that spans 13 states in the US), sits an economically distressed and rural community of the United States. Once a thriving coal-mining area, this region now is reported as one of the hardest places to live in the US. Southeastern Kentucky, located in a remote, rocky, mountainous area surrounded by rivers and valleys and prone to flooding, experienced a major flood in Spring 2013 causing significant damage to homes and critical infrastructure.
Purpose
Aims of the study were to: (1) identify and better understand the contextual variables compounding the impact of a disaster event that occurred in Spring 2013; (2) identify ways participants managed antecedent circumstances, risk, and protective factors to cope with disaster up to 12 months post-event; and (3) further determine implications for community-focused interventions that may enhance recovery for vulnerable populations to promote greater outcomes of adaptation, wellness, and readiness.
Methods
Using an ethnographic mixed-methods approach, an inter-collaborative team conducted face-to-face interviews with (N=12) Appalachian residents about their disaster experience, documented observations and visual assessment of need on an observation tool, and used photography depicting structural and environmental conditions. A Health and Emergency Preparedness Assessment Survey Tool was used to collect demographic, health, housing, environment, and disaster readiness assessment data. Community stakeholders facilitated purposeful sampling through coordination of scheduled home visits.
Results
Triangulation of all data sources provided evidence that the community had unique coping strategies related to faith and spirituality, cultural values and heritage, and social support to manage antecedent circumstances, risk, and protective factors during times of adversity that, in turn, enhanced resilience up to 12 months post-disaster. The community was found to have an innate capacity to persevere and utilize resources to manage and transcend adversity and restore equilibrium, which reflected components of resilience that deserve greater recognition and appreciation.
Conclusion
Resilience is a foundational concept for disaster science. A model of resilience for the rural Appalachia community was developed to visually depict the encompassing element of community-based interventions that may enhance coping strategies, mitigate risk factors, integrate protective factors, and strengthen access. Community-based interventions are recommended to strengthen resilience, yielding improved outcomes of adaptation, health and wellness, and disaster readiness.
BanksLH, DavenportLA, HayesMH, McArthurMA, ToroSN, KingCE, VaziraniHM. Disaster Impact on Impoverished Area of US: An Inter-Professional Mixed Method Study. Prehosp Disaster Med. 2016;31(6):583–592.
To determine if total lifetime physical activity (PA) is associated with better cognitive functioning with aging and if cerebrovascular function mediates this association. A sample of 226 (52.2% female) community dwelling middle-aged and older adults (66.5±6.4 years) in the Brain in Motion Study, completed the Lifetime Total Physical Activity Questionnaire and underwent neuropsychological and cerebrovascular blood flow testing. Multiple robust linear regressions were used to model the associations between lifetime PA and global cognition after adjusting for age, sex, North American Adult Reading Test results (i.e., an estimate of premorbid intellectual ability), maximal aerobic capacity, body mass index and interactions between age, sex, and lifetime PA. Mediation analysis assessed the effect of cerebrovascular measures on the association between lifetime PA and global cognition. Post hoc analyses assessed past year PA and current fitness levels relation to global cognition and cerebrovascular measures. Better global cognitive performance was associated with higher lifetime PA (p=.045), recreational PA (p=.021), and vigorous intensity PA (p=.004), PA between the ages of 0 and 20 years (p=.036), and between the ages of 21 and 35 years (p<.0001). Cerebrovascular measures did not mediate the association between PA and global cognition scores (p>.5), but partially mediated the relation between current fitness and global cognition. This study revealed significant associations between higher levels of PA (i.e., total lifetime, recreational, vigorous PA, and past year) and better cognitive function in later life. Current fitness levels relation to cognitive function may be partially mediated through current cerebrovascular function. (JINS, 2015, 21, 816–830)
The journalist and author W. H. Davenport Adams (1828–91) established a reputation for himself as a popular science writer, translator and lexicographer. He also wrote several children's books. In this 1889 work, Adams gives a general introduction to alchemy in Europe and traces the development of magic and alchemy in England from the fourteenth century onwards. Initially the disciplines were persecuted by the Church and met with 'the prejudice of the vulgar', languishing throughout the sixteenth and seventeenth centuries. In Book 1 Adams portrays the English 'magicians' Roger Bacon, whom he considers to have been ahead of his contemporaries; John Dee and William Lilly, astrologists of the sixteenth and seventeenth centuries, respectively; and the English Rosicrucians. Book 2 is a historical account of witchcraft in England and Scotland, from the middle ages to the witch trials of the seventeenth century, and includes a chapter on witchcraft in literature.
The theory of numbers is generally considered to be the 'purest' branch of pure mathematics and demands exactness of thought and exposition from its devotees. It is also one of the most highly active and engaging areas of mathematics. Now into its eighth edition The Higher Arithmetic introduces the concepts and theorems of number theory in a way that does not require the reader to have an in-depth knowledge of the theory of numbers but also touches upon matters of deep mathematical significance. Since earlier editions, additional material written by J. H. Davenport has been added, on topics such as Wiles' proof of Fermat's Last Theorem, computers and number theory, and primality testing. Written to be accessible to the general reader, with only high school mathematics as prerequisite, this classic book is also ideal for undergraduate courses on number theory, and covers all the necessary material clearly and succinctly.
Harold Davenport was one of the truly great mathematicians of the twentieth century. Based on lectures he gave at the University of Michigan in the early 1960s, this book is concerned with the use of analytic methods in the study of integer solutions to Diophantine equations and Diophantine inequalities. It provides an excellent introduction to a timeless area of number theory that is still as widely researched today as it was when the book originally appeared. The three main themes of the book are Waring's problem and the representation of integers by diagonal forms, the solubility in integers of systems of forms in many variables, and the solubility in integers of diagonal inequalities. For the second edition of the book a comprehensive foreword has been added in which three prominent authorities describe the modern context and recent developments. A thorough bibliography has also been added.
Lasaea rubra is an inbreeding bivalve species, living at most heights on rocky shores. Freshly collected animals from different shore heights showed significantly different upper median lethal temperatures (MLTs), with upper shore animals having higher MLTs than lower shore specimens. Experiments with animals acclimated for at least one month to a single temperature (15°C) demonstrated that these differences in upper MLT were unaffected by thermal acclimation. Electrophoretic investigation showed that the differences in thermal response had a genetic basis. Homogeneous populations of the high-water inbred line (‘Inbred line A’) had a higher MLT than homogeneous populations of ‘Inbred line C’ which was found on the middle and lower shore. No differences were detected between the MLTs of separate populations of Inbred lines A or C. A third inbred line (‘Inbred line B’) was found on the middle shore, but no homogeneous populations were found. However, indirect evidence suggests that Inbred line B has a thermal response intermediate between those of Inbred lines A and C. Study of populations made up of mixtures of inbred lines confirmed the relationship between upper MLTs and genetic composition of the population.
The object of the higher arithmetic is to discover and to establish general propositions concerning the natural numbers 1, 2, 3, … of ordinary arithmetic. Examples of such propositions are the fundamental theorem (1.4) that every natural number can be factorized into prime numbers in one and only one way, and Lagrange's theorem (V.4) that every natural number can be expressed as a sum of four or fewer perfect squares. We are not concerned with numerical calculations, except as illustrative examples, nor are we much concerned with numerical curiosities except where they are relevant to general propositions.
We learn arithmetic experimentally in early childhood by playing with objects such as beads or marbles. We first learn addition by combining two sets of objects into a single set, and later we learn multiplication, in the form of repeated addition. Gradually we learn how to calculate with numbers, and we become familiar with the laws of arithmetic: laws which probably carry more conviction to our minds than any other propositions in the whole range of human knowledge.
The higher arithmetic is a deductive science, based on the laws of arithmetic which we all know, though we may never have seen them formulated in general terms. They can be expressed as follows.
Addition. Any two natural numbers a and b have a sum, denoted by a + b, which is itself a natural number.
The marks [H] and [A] affixed to questions indicate that the questions are provided with hints and answers respectively. If both are provided [H] [A], try the hint first. The mark [M] affixed to a question indicates that it requires a little more mathematical knowledge than was assumed in the body of the book, e.g. elementary complex numbers or trigonometry. Although such matters are hard to judge, the mark [+] has been used to indicate questions, or parts of questions, that are thought to be somewhat harder than average.
The first digit of a question number indicates which chapter it refers to. Some of the questions for chapter eight are easier to answer with a programmable calculator, computer algebra system, or a spreadsheet equipped with a ‘greatest common divisor’ function. Care must be taken with operations like raising to a power to ensure that the maximum size of integer is not exceeded—none of the questions need more than 12 digits, and most need fewer.
1.1 Prove, by induction or otherwise, that:
(a) The sum of the first n numbers is n(n + 1)/2 [This result is commonly said to have been discovered by Gauss at a very early age: see, e.g., E.T. Bell, Men of Mathematics, Simon & Schuster, New York, 1937 (reprinted Penguin, 1965)];
(b) The sum of their squares is n(n + 1)(2n + 1)/6;
The higher arithmetic, or the theory of numbers, is concerned with the properties of the natural numbers 1, 2, 3, …. These numbers must have exercised human curiosity from a very early period; and in all the records of ancient civilizations there is evidence of some preoccupation with arithmetic over and above the needs of everyday life. But as a systematic and independent science, the higher arithmetic is entirely a creation of modern times, and can be said to date from the discoveries of Fermat (1601–1665).
A peculiarity of the higher arithmetic is the great difficulty which has often been experienced in proving simple general theorems which had been suggested quite naturally by numerical evidence. ‘It is just this,’ said Gauss, ‘which gives the higher arithmetic that magical charm which has made it the favourite science of the greatest mathematicians, not to mention its inexhaustible wealth, wherein it so greatly surpasses other parts of mathematics.’
The theory of numbers is generally considered to be the ‘purest’ branch of pure mathematics. It certainly has very few direct applications to other sciences, but it has one feature in common with them, namely the inspiration which it derives from experiment, which takes the form of testing possible general theorems by numerical examples. Such experiment, though necessary in some form to progress in every part of mathematics, has played a greater part in the development of the theory of numbers than elsewhere; for in other branches of mathematics the evidence found in this way is too often fragmentary and misleading.