To send content items to your account,
please confirm that you agree to abide by our usage policies.
If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your account.
Find out more about sending content to .
To send content items to your Kindle, first ensure email@example.com
is added to your Approved Personal Document E-mail List under your Personal Document Settings
on the Manage Your Content and Devices page of your Amazon account. Then enter the ‘name’ part
of your Kindle email address below.
Find out more about sending to your Kindle.
Note you can select to send to either the @free.kindle.com or @kindle.com variations.
‘@free.kindle.com’ emails are free but can only be sent to your device when it is connected to wi-fi.
‘@kindle.com’ emails can be delivered even when you are not connected to wi-fi, but note that service fees apply.
Aberrant sensitivity to social reward may be an important contributor to abnormal social behavior that is a core feature of schizophrenia. The neuropeptide oxytocin impacts the salience of social information across species, but its effect on social reward in schizophrenia is unknown.
We used a competitive economic game and computational modeling to examine behavioral dynamics and oxytocin effects on sensitivity to social reward among 39 men with schizophrenia and 54 matched healthy controls. In a randomized, double-blind study, participants received one dose of oxytocin (40 IU) or placebo and completed a 35-trial Auction Game that quantifies preferences for monetary v. social reward. We analyzed bidding behavior using multilevel linear mixed models and reinforcement learning models.
Bidding was motivated by preferences for both monetary and social reward in both groups, but bidding dynamics differed: patients initially overbid less compared to controls, and across trials, controls decreased their bids while patients did not. Oxytocin administration was associated with sustained overbidding across trials, particularly in patients. This drug effect was driven by a stronger preference for winning the auction, regardless of monetary consequences. Learning rate and response variability did not differ between groups or drug condition, suggesting that differences in bidding derive primarily from differences in the subjective value of social rewards.
Our findings suggest that schizophrenia is associated with diminished motivation for social reward that may be increased by oxytocin administration.
Maternal smoking during pregnancy (MSDP) has been linked to offspring's externalizing problems. It has been argued that socio-demographic factors (e.g. maternal age and education), co-occurring environmental risk factors, or pleiotropic genetic effects may account for the association between MSDP and later outcomes. This study provides a comprehensive investigation of the association between MSDP and a single harmonized component of externalizing: aggressive behaviour, measured throughout childhood and adolescence.
Data came from four prospective twin cohorts – Twins Early Development Study, Netherlands Twin Register, Childhood and Adolescent Twin Study of Sweden, and FinnTwin12 study – who collaborate in the EU-ACTION consortium. Data from 30 708 unrelated individuals were analysed. Based on item level data, a harmonized measure of aggression was created at ages 9–10; 12; 14–15 and 16–18.
MSDP predicted aggression in childhood and adolescence. A meta-analysis across the four samples found the independent effect of MSDP to be 0.4% (r = 0.066), this remained consistent when analyses were performed separately by sex. All other perinatal factors combined explained 1.1% of the variance in aggression across all ages and samples (r = 0.112). Paternal smoking and aggressive parenting strategies did not account for the MSDP-aggression association, consistent with the hypothesis of a small direct link between MSDP and aggression.
Perinatal factors, including MSDP, account for a small portion of the variance in aggression in childhood and adolescence. Later experiences may play a greater role in shaping adolescents’ aggressive behaviour.
Over the last decade, DNA origami has matured into one of the most powerful bottom-up nanofabrication techniques. It enables both the fabrication of nanoparticles of arbitrary two-dimensional or three-dimensional shapes, and the spatial organization of any DNA-linked nanomaterial, such as carbon nanotubes, quantum dots, or proteins at ∼5-nm resolution. While widely used within the DNA nanotechnology community, DNA origami has yet to be broadly applied in materials science and device physics, which now rely primarily on top-down nanofabrication. In this article, we first introduce DNA origami as a modular breadboard for nanomaterials and then present a brief survey of recent results demonstrating the unique capabilities created by the combination of DNA origami with existing top-down techniques. Emphasis is given to the open challenges associated with each method, and we suggest potential next steps drawing inspiration from recent work in materials science and device physics. Finally, we discuss some near-term applications made possible by the marriage of DNA origami and top-down nanofabrication.
For more than 70 years, The Americas, a publication of the Academy of American Franciscan History, has been a leading forum for scholars studying the history of Spanish America's colonial missions. As the articles collected from the journal for this special issue show, the general trend has been to move beyond the hagiographic treatment of missionaries and towards a more complex understanding of the historical roles played by the colonial missions in rural life.
Pharyngoesophageal diverticula have many subtypes, with Zenker's diverticulum being the most common. First described in 1983, a Killian–Jamieson diverticulum is an outpouching in the anterolateral wall at the pharyngoesophageal junction. This is located inferiorly to the cricopharyngeus muscle, unlike Zenker's diverticula which occur superiorly. Killian–Jamieson diverticula are rare and are commonly misdiagnosed as Zenker's diverticula. Less than 30 reports of Killian–Jamieson diverticula have been described in the literature.
A 69-year-old man presented with a 2-year symptomatic history, and was found to have simultaneous Zenker's diverticulum and Killian–Jamieson diverticulum. He was treated successfully with open surgical excision of both pouches.
Zenker's diverticulum and Killian–Jamieson diverticulum are diagnosed using radiological studies and endoscopy. Their differentiation is important, as surgical management differs. This paper reviews the literature on Killian–Jamieson diverticula and the management options available.
Blunted facial affect is a common negative symptom of schizophrenia. Additionally, assessing the trustworthiness of faces is a social cognitive ability that is impaired in schizophrenia. Currently available pharmacological agents are ineffective at improving either of these symptoms, despite their clinical significance. The hypothalamic neuropeptide oxytocin has multiple prosocial effects when administered intranasally to healthy individuals and shows promise in decreasing negative symptoms and enhancing social cognition in schizophrenia. Although two small studies have investigated oxytocin's effects on ratings of facial trustworthiness in schizophrenia, its effects on facial expressivity have not been investigated in any population.
We investigated the effects of oxytocin on facial emotional expressivity while participants performed a facial trustworthiness rating task in 33 individuals with schizophrenia and 35 age-matched healthy controls using a double-blind, placebo-controlled, cross-over design. Participants rated the trustworthiness of presented faces interspersed with emotionally evocative photographs while being video-recorded. Participants’ facial expressivity in these videos was quantified by blind raters using a well-validated manualized approach (i.e. the Facial Expression Coding System; FACES).
While oxytocin administration did not affect ratings of facial trustworthiness, it significantly increased facial expressivity in individuals with schizophrenia (Z = −2.33, p = 0.02) and at trend level in healthy controls (Z = −1.87, p = 0.06).
These results demonstrate that oxytocin administration can increase facial expressivity in response to emotional stimuli and suggest that oxytocin may have the potential to serve as a treatment for blunted facial affect in schizophrenia.
A bronchopleural fistula (BPF) is an abnormal connection between the bronchial tree and the pleural space. The development of a fistula following pulmonary resection due to a bronchial stump dehiscence is a rare and potentially fatal complication. The incidence is reported as between 1 to 20% following pneumonectomy and 0.5% after lobectomy, and reported mortality varies between 20 and 70%. The risk of death is highest when a fistula presents within the first 2 weeks after surgery, and the main cause of death is aspiration pneumonia.
The most common aetiology of a bronchopleural fistula is a complication of pulmonary resection, either segmentectomy, lobectomy or pneumonectomy. This chapter will focus upon post-operative fistulae, but they can occur in the non-operative setting. Non-operative fistulae can be caused by a necrotizing pneumonia or empyema and neoplasms of lung, thyroid, oesophagus or the lymphatic system. Also, they can be secondary to blunt or penetrating chest trauma or as a complication of medical procedures such as radiotherapy, lung biopsy or chest drain insertion. The ‘air leak’ responsible for causing a pneumothorax is often erroneously referred to as a bronchopleural fistula, but these leaks are alveolarpleural fistulae, rather than the more proximally located bronchopleural fistulae.
The risk factors for post-resection fistula formation can be classified into pre-operative, intra-operative and post-operative factors. Table 20.1 shows a list of risk factors which have been suggested to predispose to BPF after lung resection. Pre-operative factors focus upon co-morbidities, drug history and any pre-operative oncological treatment. Algar et al. found a significant association between development of BPF and COPD, hyperglycaemia, hypoalbuminaemia, steroid therapy and low predicted post-operative FEV1. A multivariate analysis by Asamura et al. of risk factors for BPF in 1,360 pulmonary resections for lung cancer reported similar findings but in addition found an increased risk associated with liver cirrhosis and pre-operative radiotherapy in excess of 5,000 Gy.
Intra-operatively, Asamura et al. identified right-sided resection, pneumonectomy (especially right-sided), mediastinal lymph node dissection and residual carcinoma at the bronchial stump as technical factors predisposing to fistula formation. Also, long and devascularized bronchial stumps are reported as risk factors. The mechanisms for the increased risk related to right-sided resections are two-fold. Firstly, the right main bronchus is usually supplied by one bronchial artery, whereas the left is supplied by two bronchial arteries.
At the first meeting of the newly formed Commission on Spectrophotometry, at Paris in 1935, a thorough discussion, aided by several reports, took place on the principles of this branch of astrophysics. So it will be sufficient now to treat only such special points of theory and practice as have won interest by researches of the last few years.
The majority of the members of the Commission have been good enough to send in full reports regarding subjects of interest to this Commission. Extracts from them relating to questions which may be the subject of useful discussion at the forthcoming meeting in Paris are given below; references to research undertaken during the last three years, particulars of which are readily available in recent astronomical publications, are omitted.
The present report is the first for which this newly-formed Commission has been responsible. In view of this fact, and in view of the still exploratory nature of many investigations in spectrophotometry, as well as the need for the highest measure of individuality in the attack of the not simple problems involved, it would be premature to propose, simple though it might be to do so, any far reaching plans for co-operative schemes of investigation. These undoubtedly will play a part in the later work of the Commission, but what appears to be needed now is a closer definition of the aims of spectrophotometry, and at least a reference to the many branches of the subject where investigation is needed. The present report attempts to deal with these topics in three successive sections, concerned in turn with the unique property of spectrophotometric measures, the fields of application of spectrophotometry, and recent developments in a still incomplete and difficult technique.
The absolute magnitudes of pulsating variable stars, both RR Lyrae stars and Cepheid variables, may be assessed from observation in three ways: by the classical method of statistical parallaxes, by their occurrence in star clusters whose distance is otherwise known, particularly by ascertaining the position of the main sequence in the HR diagram, and by the Baade-Wesselink method of determining stellar diameters.
As regards the first of these, the method of statistical parallaxes, the RR Lyrae stars lend themselves to this better than do the Cepheid variables, because the velocities relative to the Sun are so much larger. RR Lyrae radial velocities are frequently as high as 200 km/sec or even 300 km/sec, and as many of the stars lie at distances between 1000 and 1500 pc the proper motions of the transverse velocities may be expected to be as high as 0”.050 per annum. And, indeed, many investigations have been made recently, among which one may mention those by Plaut, by van Herk, and by the Royal Greenwich Observatory.
The Reverse Engineering Road to Computing Life
Philip K. Maini, Mathematical Institute, Andrew Wiles Building, Radcliffe Observatory Quarter, Woodstock Road, Oxford OX2 6GG, UK,
Thomas E. Woolley, Mathematical Institute, Andrew Wiles Building, Radcliffe Observatory Quarter, Woodstock Road, Oxford OX2 6GG, UK,
Eamonn A. Gaffney, Mathematical Institute, Andrew Wiles Building, Radcliffe Observatory Quarter, Woodstock Road, Oxford OX2 6GG, UK,
Ruth E. Baker, Mathematical Institute, Andrew Wiles Building, Radcliffe Observatory Quarter, Woodstock Road, Oxford OX2 6GG, UK
Elucidating the mechanisms underlying the formation of structure and form is one of the great challenges in developmental biology. From an initial, seemingly spatially uniform mass of cells, emerge the spectacular patterns that characterise the animal kingdom – butterfly wing patterns, animal coat markings, skeletal structures, skin organs, horns etc. (Figure 9.1). Although genes obviously play a key role, the study of genetics alone does not tell us why certain genes are switched on or off in specific places and how the properties they impart to cells result in the highly coordinated emergence of pattern and form. Modern genomics has revealed remarkable molecular similarity among different animal species. Specifically, biological diversity typically emerges from differences in regulatory DNA rather than detailed protein coding sequences. This implicit universality highlights that many aspects of animal development can be understood from studies of exemplar species such as fruit flies and zebrafish while also motivating theoretical studies to explore and understand the underlying common mechanisms beyond a simply descriptive level.
However, when Alan Turing wrote his seminal paper, ‘The chemical basis of morphogenesis’ (Turing, 1952), such observations were many decades away. At that time biology was following a very traditional classification route of list-making activities. Indeed, there was very little theory regarding development other than D'Arcy Thompson's classic 1917 work (see Thompson, 1992, for the abridged version) exploring how biological forms arose, though even this was still very much at the descriptive rather than the mechanistic level.
Undeterred, Turing started exploring the question of how developmental systems might undertake symmetry-breaking and thus create and amplify structure from seeming uniformity. For example, if one looks at a cross-section of a tree trunk, it has circular symmetry which is broken when a branch starts to grow outwards. Turing proposed an underlying mechanism explaining how asymmetric structure could emerge dynamically, without innate hardwiring. In particular, he described how a symmetric pattern, for instance of a growth hormone, could break up so that more hormone was concentrated on one part of the circle, thus inducing extra growth there.
In order to achieve such behaviour Turing came up with a truly ingenious theory. He considered a system of chemicals reacting with each other and assumed that in the well-mixed case (no spatial heterogeneities) this system exhibited an equilibrium (steady) state which was stable.
Magnetic resonance imaging studies of maltreated children with posttraumatic stress disorder (PTSD) suggest that maltreatment-related PTSD is associated with adverse brain development. Maltreated youth resilient to chronic PTSD were not previously investigated and may elucidate neuromechanisms of the stress diathesis that leads to resilience to chronic PTSD. In this cross-sectional study, anatomical volumetric and corpus callosum diffusion tensor imaging measures were examined using magnetic resonance imaging in maltreated youth with chronic PTSD (N = 38), without PTSD (N = 35), and nonmaltreated participants (n = 59). Groups were sociodemographically similar. Participants underwent assessments for strict inclusion/exclusion criteria and psychopathology. Maltreated youth with PTSD were psychobiologically different from maltreated youth without PTSD and nonmaltreated controls. Maltreated youth with PTSD had smaller posterior cerebral and cerebellar gray matter volumes than did maltreated youth without PTSD and nonmaltreated participants. Cerebral and cerebellar gray matter volumes inversely correlated with PTSD symptoms. Posterior corpus callosum microstructure in pediatric maltreatment-related PTSD differed compared to maltreated youth without PTSD and controls. The group differences remained significant when controlling for psychopathology, numbers of Axis I disorders, and trauma load. Alterations of these posterior brain structures may result from a shared trauma-related mechanism or an inherent vulnerability that mediates the pathway from chronic PTSD to comorbidity.
In the spring of 1935 I was commissioned by the Trustees of the British Museum to examine the possibilities of excavation in North Syria. The object which I had in view was the discovery of any links that might exist between the civilisation of Minoan Crete and that of the Asian mainland, and to a large extent therefore the search was conditioned by the geographical nature of the country. If such connexion existed it would require trade-routes, and it was only along those that material evidence of inter-communication could be found; therefore the first requisite was a harbour as a terminus for the oversea traffic and easy communications between the harbour and the interior, i.e., communications not merely with the immediate hinterland, but also with the known cultural centres of the Near East. By the latter consideration the southern coast sites were ruled out; Palestine was never other than a poor country; South Syria was not likely to be profitable, for, in spite of its importance, Damascus is difficult of access from the sea, and from it the caravan route to Mesopotamia has to make the big detour round the north end of the Syrian desert.
The deviation of the vertex of the velocity ellipse of stars of spectral class A is shown clearly in a diagram published by Strömberg (1946); no such clear deviation is shown by the velocity ellipses of stars of other spectral types in his diagrams. This deviation of the vertex or tilt of the velocity ellipse can have some connexion with spiral structure, and there seem to be two possibilities, (a) that the tilt is confined to young stars only, and has something to do with an initial condition of their formation; and (b) that the tilt is a manifestation of the nature of the attracting field in the neighbourhood of the sun, which is not central on account of the attractions of spiral arms.
The present note examines data taken from the velocities of nearby stars, and uses the classification of the late type main sequence stars put forward by Wilson, based on observations of the reversals in the Ca+ H and K lines.
From this material it is concluded that the vertex deviation is confined to young stars, and that hypothesis (a) rather than hypothesis (b) is correct – or at least strongly indicated by available observations. The paper goes on to show that the deviation of the vertex can be explained by supposing that the stars were formed comparatively recently in a thin strip of the galaxy more or less at right angles to the direction of the galactic centre – in fact, in something like a spiral arm.
The material which I wish to present today is set out in Royal Observatory Bulletin Number 66, of which I have a few advance copies with me. The paper describes measures of about 700 stars in an area about 1° square. These are nearly all the stars down to a limit of V =14m5 in the area. Proper motions were measured by comparison between two plates taken on 1912 Jan. 21 and 1960 Nov. 16–17. The earlier plate had an exposure of 5 hr, which is exceptionally long for astrographic plates of those times. The measures of Ax and Ay (the shifts in units of one-tenth of a micron in the directions of right ascension and declination) were reduced by constructing plate constants such as would make the least-squares motion of the stars with B – V < 0 zero. In the reduction 104 such stars were used. The standard errors of measurement are σ(x) = ±15·9 and σ(y) = ±14·9, assuming that these stars really are members of the LMC and exhibit no relative proper motion. By using these plate constants, values of Ax and Ay were computed for all the remaining stars. The stars with 0·5 < B – V < 1·5 (apart from cepheids and a few reddened stars) are very plainly shown by their proper motions to be nearly all field stars, and indeed their motions can be satisfactorily explained by supposing them to be galactic stars showing the parallactic motion, galactic rotation, and a velocity ellipse appropriate to galactic stars. Stars with B – V > 1 · 5 cannot be determined to be members of the LMC on proper motion alone, but other considerations suggest that this is so. For example, their x, y distribution in the field follows the same pattern as that shown by the very blue stars, whereas the field stars (0 · 5 < B – V < 1 · 5) are uniformly distributed over the plate.
Some years ago (1960) I discussed the HR diagram of the variable star field investigated at Herstmonceux as the result of Drs. Sandage and Eggen's visit to Pretoria, and found colour-luminosity arrays showing mainly very blue giant stars; and later (1961) I suggested that a second and older population could be seen in the same area of the LMC, showing a rather different x,y distribution. Recently Miss Epps has assisted me to make further investigations into the matter. We are now discussing stars fainter than V = 14 · 5 and therefore too faint for us to determine their proper motions. In order to get rid of foreground stars which obscure the HR diagram we have had to make use of the x, y distribution to discriminate between LMC members and foreground stars. Firstly, we examined an open cluster which appears as a faint object on the 74-inch Pretoria plates. It is away from the main lane occupied by the bright blue objects, and its appearance on the B and V plates showed it not to be excessively blue. On a Radcliffe plate (74 in. stopped to 44 in.) with an exposure of 20 min, 29 stars can be seen within a circle of diameter of 1′ of arc. We have been able to determine V accurately for only 15 of these stars, one of which proved to be a variable of period 4–75 days. The HR diagram shows a gap between B – V = 0 · 2 and B – V = 1 · 0, the variable being in this gap. It is comparable with those of NGC 129, NGC 2287, and NGC 6067, and, by analogy with these objects, the open cluster now described probably has an age of about 108 years. The object is of course very different from the young or blue (but tight) cluster NGC 1818 not far away from it.