bluuebunny/crossref_metadata_2025 huggingface dataset:
Italy's disappearing ‘red regions’: a longitudinal analysis
Authors: Bracalente Bruno , Pellegrino Davide , Forcina Antonio
Published: June 2020

Using an analysis of time series data over an extended period, this article describes the waning strength of the left-wing vote in Italy's ‘red regions’. By analysing changes to the provincial share of the vote for successive principal left-wing parties over the period 1953–2018, the degree of continuity in relation to the left's traditional territorial entrenchment is assessed. It becomes clear that after an extended period of minimal change, in more recent years there has been an increasing disruption of previous patterns. A thorough analysis of voter transitions during the 2001–19 period in Umbria, the first red region in which the left lost control of the regional government, shows that in this case the gradual weakening of the traditional left-wing ‘vote of belonging’ has experienced a dramatic acceleration during the more recent period. This has been expressed in a growing rate of abstention, vote-switching according to the type of electoral contest, and a marked propensity to vote for populist movements and parties on both the left and right.
Gender, Education, and Enlightened Politics in Plato’sLaws
Authors: RABIEH LINDA R.
Published: June 2020

Plato’s treatments of women are perplexing because they seem to justify both gender equality and female subordination. Faced with evidence of both, scholars typically ask whether Plato promotes gender equality or patriarchy rather than what a particular treatment of women means in the dialogue to which it belongs. This article seeks to clarify Plato’s treatment of women by focusing on women’s education in theLawsand analyzing it in the context of his Athenian Stranger’s attempt at rational political reform. It argues that in exploring the differences between men and women, Plato shows them to be ones of degree rather than kind and identifies a common human weakness shared by both genders that is the greatest obstacle to his reform. This approach reveals a profound examination of ahumanproblem and an instructive account of the challenges that accompany the quest for gender equality.
Exploratory tympanotomy in sudden sensorineural hearing loss for the identification of a perilymphatic fistula – retrospective analysis and review of the literature
Authors: Heilen S , Lang C P , Warnecke A , Lenarz T , Durisin M
Published: June 2020

Objective

The diagnostic value of exploratory tympanotomy in sudden sensorineural hearing loss remains controversial. This study and review were performed to identify the incidence of perilymphatic fistula in patients with sudden sensorineural hearing loss. The effectiveness of tympanotomy for sealing of the cochlear windows in cases with perilymphatic fistula was evaluated.

Methods

A search in common databases was performed. Overall, 5034 studies were retrieved. Further, a retrospective analysis on 90 patients was performed.

Results

Eight publications dealing with tympanotomy in patients with sudden sensorineural hearing loss were identified. In 90 patients diagnosed with sudden sensorineural hearing loss and undergoing exploratory tympanotomy, 10 patients (11 per cent) were identified with a perilymphatic fistula, and this corresponds to the results obtained from our review (13.6 per cent).

Conclusion

There was no significant improvement after exploratory tympanotomy and sealing of the membranes for patients with a definite perilymphatic fistula.
Pseudo mastoid obliteration with conchal cartilage may be a safe alternative technique for cochlear implantation in canal wall down mastoidectomy with large meatoplasty
Authors: Carnevale C , Til-Pérez G , Arancibia-Tagle D , Tomás-Barberán M , Sarría-Echegaray P
Published: June 2020

Objective

Safe cochlear implantation is challenging in patients with canal wall down mastoid cavities, and the presence of large meatoplasties increases the risk of external canal overclosure. This paper describes our results of obliteration of the mastoid cavity with conchal cartilage as an alternative procedure in cases of canal wall down mastoidectomy with very large meatoplasty.

Methods

The cases of seven patients with a canal wall down mastoidectomy cavity who underwent cochlear implantation were retrospectively reviewed. Post-operative complications were analysed. The mean follow-up duration was 4.5 years.

Results

There was no hint of cholesteatoma recurrence and all patients have been free of symptoms during follow up. Only one patient showed cable extrusion six months after surgery, and implantation of the contralateral ear was needed.

Conclusion

Pseudo-obliteration of the mastoid cavity with a cartilage multi-layered palisade reconstruction covering the electrode may be a safe alternative in selected patients with a large meatoplasty.
Investigating the learning curve in endoscopic compared to microscopic myringotomy and ventilation tube insertion
Authors: Denton O , Daglish A , Smallman L , Fishpool S
Published: June 2020

Objective

Rate of learning is often cited as a deterrent in the use of endoscopic ear surgery. This study investigated the learning curves of novice surgeons performing simulated ear surgery using either an endoscope or a microscope.

Methods

A prospective multi-site clinical research study was conducted. Seventy-two medical students were randomly allocated to the endoscope or microscope group, and performed 10 myringotomy and ventilation tube insertions. Trial times were used to produce learning curves. From these, slope (learning rate) and asymptote (optimal proficiency) were ascertained.

Results

There was no significant difference between the learning curves (p = 0.41). The learning rate value was 68.62 for the microscope group and 78.71 for the endoscope group. The optimal proficiency (seconds) was 32.83 for the microscope group and 27.87 for the endoscope group.

Conclusion

The absence of a significant difference shows that the learning rates of each technique are statistically indistinguishable. This suggests that surgeons are not justified when citing ‘steep learning curve’ in arguments against the use of endoscopes in middle-ear surgery.
Novel use of high-flow nasal cannula therapy in the management of pyriform aperture stenosis: case report
Authors: Fuzi J , Teng A , Saddi V , Soma M
Published: June 2020

Background

Pyriform aperture stenosis is a rare form of congenital nasal obstruction; it poses a management dilemma for otolaryngologists and physicians alike. It can result in poor weight gain and potentially life-threatening airflow obstruction. The challenge lies in the difficulty to predict which patients will require invasive operative management versus conservative therapy alone.

Case report

This case demonstrates the successful use of high-flow nasal cannula therapy in a young child with pyriform aperture stenosis.
A family of Vlasov–Maxwell equilibrium distribution functions describing a transition from the Harris sheet to the force-free Harris sheet
Authors: Neukirch T. , Wilson F. , Allanson O.
Published: June 2020

We discuss a family of Vlasov–Maxwell equilibrium distribution functions for current sheet equilibria that are intermediate cases between the Harris sheet and the force-free (or modified) Harris sheet. These equilibrium distribution functions have potential applications to space and astrophysical plasmas. The existence of these distribution functions had been briefly discussed by Harrison & Neukirch (Phys. Rev. Lett., vol. 102, (2009a), 135003), but here it is shown that their approach runs into problems in the limit where the guide field goes to zero. The nature of this problem will be discussed and an alternative approach will be suggested that avoids the problem. This is achieved by considering a slight variation of the magnetic field profile, which allows a smooth transition between the Harris and force-free Harris sheet cases.
Metal production and social organisation in fourteenth-century Singapore
Authors: Zaini Shah Alam
Published: June 2020

Ancient Singapore is often discussed exclusive of its cultural and historical context, a backward projection of the modern, independent city-state. Temasek is understood mainly in terms of being a maritime entrepôt with extensive trade connections. This research is interested in Temasek as a proto-historic Malay port-city, namely its social, political and economic organisation. It is an aspect of early Singapore, and of the Malay World, in general, we know very little about. However, more than three decades of archaeology have provided a wealth of data related to daily life in the settlement and the data has provided hints of a diverse sociocultural landscape. This study focuses on the relationship between metal production and social organisation, and employs a conceptual and interpretative framework that is both multidisciplinary and cross-cultural. Craft production is as much a social and political phenomenon as an economic and technological one, and studies of production systems can shed light on issues of power and control over resources and labour. The data suggest the presence of a social stratum that could generate and mobilise resources independent of the ruling elite. Metals were rare and valuable commodities during this period, however, the ruling class in Temasek did not appear to control nor restrict production of iron and copper-based goods as it did with glass. The results are by no means the final word on ancient Singapore or Malay society. Instead it provides a provisional model that can be tested with archaeological data, refined and expanded as more material becomes available.
Dutch objections to British Singapore, 1819–1824: Law, politics, commerce and a diplomatic misstep
Authors: Borschberg Peter
Published: June 2020

The year 1819 is almost universally taken as a seminal date in Singapore historiography. Yet Stamford Raffles’ founding of a British trading post there was controversial from the start. The Dutch and the British haggled as to whether or not Raffles had overstepped his authority, and whether the trading post was legal. From the start, the Dutch demanded that the British quit their occupation of Singapore. During a three-year hiatus in the Anglo–Dutch negotiations (1820–23), Anton Reinhard Falck, the lead Dutch negotiator, decided to drop claims to Singapore in favour of a rearrangement of possessions in the archipelago. Crucially, he concluded that dropping claims over Singapore would not amount to a real loss. Instead, Falck hoped to use Singapore as a bargaining chip to squeeze additional concessions from the British. The Dutch formally relinquished their claim over Singapore in article 12 of the Anglo-Dutch Treaty, which gave full recognition and legitimacy to the British post, and sanctioned a breakup of the Johor-Riau Empire with the Singapore Straits acting as a notional dividing line. Earlier studies were substantially based on English-language materials and present the British as dominating the negotiations. The present article, based on Dutch archival materials as well as studies and sources in French, Dutch and English, reveals a fuller story of diplomatic disputes, territorial concessions, errors of judgement, and the triggering of the Dutch empire in the archipelago, in a paper war for the contested space of Singapore.
Commemorating Raffles: The creation of an imperial icon in colonial Singapore
Authors: Barnard Timothy P.
Published: June 2020

While Sir Thomas Stamford Raffles led the expedition that founded colonial Singapore in 1819 and conceptualised many of the early institutions that developed the trade port, it was the depiction and commemoration of his time in the region that made him an icon of imperial mythology. This was part of a process in which admiration of his name and exploits were exalted, ultimately representing a core element in the Victorian mentality, the need to create heroes to glorify the British Empire. This article will survey and analyse how the commemoration of Raffles in the first 75 years of colonial rule, through the commissioning of statues and the attachment of his name to establishments and institutions, solidified and justified a British presence in the region and larger imperial history, which continues to echo in the modern nation-state of Singapore and its history.
Raffles restitution: Artistic responses to Singapore's 1819 colonisation
Authors: Ng Yi-Sheng
Published: June 2020

1819 represents a highly charged moment in the Singapore imagination. It marks the birth of our modern city-state, yet it also signals the beginning of our colonisation: the domination of Malay and other Asian cultures by Western powers. Artists have thus responded to the event with widely variant attitudes, ranging from E.W. Jesudason's laudatory Raffles Institution Anthem (c.1963–66) to Isa Kamari's stridently anti-colonial novel, Duka Tuan Bertakhta / 1819 (2011). The prevailing sentiment, however, has been one of playful ambivalence. While accepting the fact of colonisation, artists have rejected a founding myth that glorifies our primary colonist, Sir Stamford Raffles. Instead, we have lampooned him in works like Robert Yeo's play The Eye of History (1991) and Colin Goh's film Talking Cock: The Movie (2002); raised ourselves to the height of his statue in Lee Wen's art event Untitled (Raffles) (2001); highlighted narratives of overlooked figures in the drama of colonisation: William Farquhar, Sophia Raffles, Nonio Clement, Sultan Hussein Shah, Munsyi Abdullah, and Sang Nila Utama. As a cultural researcher and author of the biographical drama The Last Temptation of Stamford Raffles (2008), I shall examine trends behind these divergent representations of our colonisation. I argue that artists have chosen to retell 1819 not as a year of conquest, but as a polymorphous moment of transformative contact between East and West; one in which we may view ourselves, not as the victims of change, but as its agents.
Big cats in borderlands: challenges and implications for transboundary conservation of Asian leopards
Authors: Farhadinia Mohammad S. , Rostro-García Susana , Feng Limin , Kamler Jan F. , Spalton Andrew , Shevtsova Elena , Khorozyan Igor , Al-Duais Mohammed , Ge Jianping , Macdonald David W.
Published: June 2020

Large carnivores have extensive spatial requirements, with ranges that often span geopolitical borders. Consequently, management of transboundary populations is subject to several political jurisdictions, often with heterogeneity in conservation challenges. In continental Asia there are four threatened leopard subspecies with transboundary populations spanning 23 countries: the Persian Panthera pardus saxicolor, Indochinese P. pardus delacouri, Arabian P. pardus nimr and Amur P. pardus orientalis leopards. We reviewed the status of these subspecies and examined the challenges to, and opportunities for, their conservation. The Amur and Indochinese leopards have the majority (58–100%) of their remaining range in borderlands, and the Persian and Arabian leopards have 23–26% of their remaining ranges in borderlands. Overall, in 18 of 23 countries the majority of the remaining leopard range is in borderlands, and thus in most countries conservation of these subspecies is dependent on transboundary collaboration. However, we found only two transboundary initiatives for Asian leopards. Overall, we highlighted three key transboundary landscapes in regions that are of high importance for the survival of these subspecies. Recent listing of the leopard in the Bonn Convention on the Conservation of Migratory Species of Wild Animals is important, but more international collaboration is needed to conserve these subspecies. We provide a spatial framework with which range countries and international agencies could establish transboundary cooperation for conserving threatened leopards in Asia.
Prospection does not imply predictive processing
Authors: Litwin Piotr , Miłkowski Marcin
Published: June 2020

Predictive processing models of psychopathologies are not explanatorily consistent with the present account of abstract thought. These models are based on latent variables probabilistically mapping the structure of the world. As such, they cannot be informed by representational ontology based on mental objects and states. What actually is the case is merely some terminological affinity between subjective and informational uncertainty.
Abstraction: An alternative neurocognitive account of recognition, prediction, and decision making
Authors: Reyna Valerie F. , Broniatowski David A.
Published: June 2020

Gilead et al. offer a thoughtful and much-needed treatment of abstraction. However, it fails to build on an extensive literature onabstraction,representational diversity,neurocognition, andpsychopathologythat provides important constraints and alternative evidence-based conceptions. We draw on conceptions in software engineering, socio-technical systems engineering, and a neurocognitive theory with abstract representations of gist at its core, fuzzy-trace theory.
The productive mind: Creativity as a source of abstract mental representations
Authors: Fedyk Mark , Xu Fei
Published: June 2020

Explanations of how the brain makes successful predictions should refer to abstracta. But, the mind/brain system is for more than prediction alone. Creativity also plays an important role in supply the mind/brain system with abstracta that serve a number of valuable ends over and above prediction.
A challenge for predictive coding: Representational or experiential diversity?
Authors: Vilas Martina G. , Melloni Lucia
Published: June 2020

To become a unifying theory of brain function, predictive processing (PP) must accommodate its rich representational diversity. Gilead et al. claim such diversity requires a multi-process theory, and thus is out of reach for PP, which postulates a universal canonical computation. We contend this argument and instead propose that PP fails to account for the experiential level of representations.
Other and other waters in the river: Autism and the futility of prediction
Authors: Belmonte Matthew K.
Published: June 2020

Autism has been described as a neural deficit in prediction, people with autism manifest low perceptual construal and are impaired at traversing psychological distances, and Gilead et al.'s hierarchy from iconic to multimodal to fully abstract, socially communicated representations is exactly the hierarchy of representational impairment in autism, making autism a natural behavioural and neurophysiological test case for the prediction–abstraction relationship.
Shared reality and abstraction: The social nature of predictive models
Authors: Rossignac-Milon Maya , Pinelli Federica , Higgins E. Tory
Published: June 2020

We propose that abstraction is an interpersonal process and serves a social function. Research on shared reality shows that in communication, people raise their level of abstraction in order to create a common understanding with their communication partner, which can subsequently distort their mental representation of the object of communication. This work demonstrates that, beyond building accurate models, abstraction also functions to build socially shared models – to create a shared reality.
Above and beyond “Above and beyond the concrete”
Authors: Gilead Michael , Trope Yaacov , Liberman Nira
Published: June 2020

The commentaries address our view of abstraction, our ontology of abstract entities, and our account of predictive cognition as relying on relatively concrete simulation or relatively abstract theory-based inference. These responses revisit classic questions concerning mental representation and abstraction in the context of current models of predictive cognition. The counter arguments to our article echo: constructivist theories of knowledge, “neat” approaches in artificial intelligence and decision theory, neo-empiricist models of concepts, and externalist views of cognition. We offer several empirical predictions that address points of contention and that highlight the generative potential of our model.
Efficient and Safe Motion Planning for Quadrotors Based on Unconstrained Quadratic Programming
Authors: Li Yanhui , Liu Chao
Published: June 2020

An autonomous motion planning framework is proposed, consisting of path planning and trajectory generation. Primarily, a spacious preferred probabilistic roadmap algorithm is utilized to search a safe and short path, considering kinematics and threats from obstacles. Subsequently, a minimum-snap and position-clearance polynomial trajectory problem is transformed into an unconstrained quadratic programming and solved in a two-step optimization. Finally, comparisons with other methods based on statistical simulations are implemented. The results show that the proposed method achieves computational efficiency and a safe trajectory.
COMPREHENSION OF FOCUS-TO-ACCENTUATION MAPPING IN SENTENCES WITHONLYBY ADVANCED CANTONESE LEARNERS AND DUTCH LEARNERS OF ENGLISH
Authors: Ge Haoyan , Chen Aoju , Yip Virginia
Published: June 2020

This study investigates L2 comprehension of focus-to-accentuation mapping in English sentences with focus particleonlyby advanced learners of English whose L1 was either Cantonese or Dutch. Two experiments were conducted to examine (a) whether L2 learners could map accentuation to focus; and (b) whether they could perceive accentuation in English sentences. Results show that accentuation played little role in Cantonese learners’ comprehension of focus, whereas it affected how accurately and quickly Dutch learners and native controls comprehended focus. Dutch learners were even more efficient than native controls in comprehending focus-to-accentuation mapping. Furthermore, both L2 groups could successfully perceive accentuation in English sentences. These findings suggest that multiple interfaces might not be equally problematic for L2 learners with different L1s, and convergence at multiple interfaces in L2 is possible. The comprehension difficulty observed in Cantonese learners can be attributed to their less detailed representation of focus-to-accentuation mapping in L2.
Introductory Remarks
Authors: Simon G.T.
Published: June 2020

Forty years ago in the University of Toronto, a group of young
physicists constructed the first electron microscope in North America. With
Toronto as the host for the 9th International Congress on Electron
Microscopy in 1978, it is an unique opportunity to commemorate this Canadian
achievement. In the summer of 1977, Cecil Hall, who was involved in this
achievement, wrote in a letter about this commemoration: “It is only a
ceremony, of course, a symbolic summation to a story that many of us know.
It is a good story”. That it is more than a “good story” became clear while
material was being gathered to write the historical account of the
construction of the Toronto microscope.
Measurement and Reduction of Radiation Damage in Frozen Hydrated
Crystalline Specimens
Authors: Glaeser R.M. , Hayward S.B.
Published: June 2020

Highly ordered or crystalline biological macromolecules become severely
damaged and structurally disordered after a brief electron exposure.
Evidence that damage and structural disorder are occurring is clearly given
by the fading and eventual disappearance of the specimen's electron
diffraction pattern. The fading and disappearance of sharp diffraction spots
implies a corresponding disappearance of periodic structural features in the
specimen. By the same token, there is a oneto- one correspondence between
the disappearance of the crystalline diffraction pattern and the
disappearance of reproducible structural information that can be observed in
the images of identical unit cells of the object structure.

The electron exposures that result in a significant decrease in the
diffraction intensity will depend somewhat upon the resolution (Bragg
spacing) involved, and can vary considerably with the chemical makeup and
composition of the specimen material.
Reconstruction of the Structure of Enzymes from their Images
Authors: Kiselev N.A.
Published: June 2020

Electron microscopic studies on proteins require solution of the following problems: 1/ when preparing the samples one strives for preservation of structure and its better revelation by staining; 2/ elect ron microscopy at maximal resolution and with minimal radiation damages; 3/ interpretation of images, their processing through optical and mathematical methods. All these problems are inseparably linked with one another, therefore, while concentrating attention on point 3, we shall also touch upon the first two.

Until now, negative staining has been the most effective method for enhancing contrast of protein molecules and protecting structure during drying. For the sake of simplicity, the molecule images on micrographs may be regarded as patterns of stain distribution around the structure. In reality, the fine details around the edges of protein molecules can be lost in the depths of stain.
The Structures of Glutamine Synthetase and Cytochrome c Oxidase — Studies by Electron Microscopy and Image Analysis
Authors: Frey T.G.
Published: June 2020

A number of physical and chemical techniques are available for the study of macro-molecular protein structure. One of the most direct is the use of electron microscopy, but its use with biological structures suffers from many problems and limitations related to noise, contrast, and specimen damage by the electron beam. Many of these problems can be alleviated through the use of techniques of images analysis which have been developed in recent years (Crowther and Klug, 1975). I would like to present two examples demonstrating how electron microscopy and image analysis have been applied to the structural study of a soluble enzyme, glutamine synthetase, and a membrane-bound enzyme, cytochrome c oxidase.
Limitations for the Resolving Power of Electron Microscopes
Authors: Scherzer O.
Published: June 2020

The change from light microscopy to electron microscopy was a big step in the direction to make small things visible. Yet there are three troublesome limitations for the resolving power of electron microscopes: electron diffraction, radiation damage, and money.
The Imaging of Crystal Structures and Crystal Defects
Authors: Cowley J.M.
Published: June 2020

The problem of "understandinq" electron microscope imaqes becomes more
acute as the resolution is improved. The naive interpretation of an imaqe as
representinq the projection of an atom density becomes less and less
appropriate. We are increasinqly forced to face the complexities of coherent
imaqinq of what are essentially phase objects.

Most electron microscopists are now aware that, for very thin weakly
scatterinq objects such as thin unstained bioloqical specimens, hiqh
resolution imaqes are best obtained near the optimum defocus, as prescribed
by Scherzer, where the phase contrast imaqe qives a qood representation of
the projected potential, apart from a lack of information on the lower
spatial frequencies. But phase contrast imaqinq is never simple except in
idealized limitinq cases.
Single Atoms in Molecules and Crystals Observed by Transmission Electron Microscopy
Authors: Hashimoto H. , Kumao A. , Endoh H.
Published: June 2020

Modern conventional transmission electron microscopes operated at 100 kV have the point to point resolution of around 2.5 Å and fringe resolution of 0.5 Å which are the same order of single atoms. Observation of single atoms, however, is not so easy because of the low contrast of the image. Successful results could be obtained only by using the method to enhance the contrast (Hashimoto et al 1971, 1973, Henkelman and Ottensmayer 1971, Philips et al 1972, Ottensmayer et al 1972, Thon et al 1972) and also to eliminate the noise (Formanek et al 1971, Hashimoto et al 1974, Spense 1975, Mihama et al 1976, Iijima 1977), which come from the supporting film and specimen itself. In the present paper, the important factor and technique to observe the image of single atoms in molecules and their clusters are discussed and some application to the observation of crystal growth will be shown.
Structure and Assembly of the Escherichia coli Ribosome
Authors: Wittman H.G. , Nierhaus K.H. , Sieber G. , Stoffler G. , Tesche B. , Tischendorf G.W. , Wittman-Liebold B.
Published: June 2020

Biosynthesis of proteins takes place on ribosomes which are multi-component particles occurring in all organisms. There are two classes of ribosomes in nature: the 80S ribosomes present in the cytoplasm of eukaryotic cells and the 70S ribosomes in prokaryotes. Ribosomes in chloroplasts and mitochondria are related to the prokaryotic ribosomes, although their sedimentation coefficients differ in many cases from 70S.

Components

The best known ribosome is that of the bacterium E. coli. It consists of two subunits of unequal size (30S and 50S). Besides three RNA molecules (5S, 16S and 23S) there are many ribosomal proteins. Their number was first determined by two-dimensional polyacrylamide electrophoresis.
Preparatory Procedures for Electron Microscopic Analysis at the Molecular
Level of Resolution
Authors: Sjostrand F.J.
Published: June 2020

In the 1940's and 1950's electron microscopy conferences were attended
with everybody interested in learning about the latest technical
developments for one very obvious reason. There was the electron microscope
with its outstanding performance but nobody could make very much use of it
because we were lacking proper techniques to prepare biological specimens.
The development of the thin sectioning technique with its perfectioning in
1952 changed the situation and systematic analysis of the structure of cells
could now be pursued.

Since then electron microscopists have in general become satisfied with
the level of resolution at which cellular structures can be analyzed when
applying this technique. There has been little interest in trying to push
the limit of resolution closer to that determined by the resolving power of
the electron microscope.
Morphological and Chemical Organisation of Gap Junctions
Authors: Revel J.P.
Published: June 2020

In 1963 when J. D. Robertson showed the occurrence of a subunit pattern
in cell membranes at the level of the electrical synapses in the Mauthner
cells of the goldfish brain it would have been difficult to predict that the
gap junction (alias nexus (Dewey and Barr, 1962) or, as suggested more
recently, macula communicans (Simionescu et al., 1975)) would come to be
considered an almost universal means of communication between cells. There
is evidence for cell-cell coupling, or for the presence of gap junctions (or
both) in most mammalian tissues or organs, save for red blood cells,
spermatozoa and skeletal muscle cells. While gap junctions appear to be
absent in organisms such as Dictyostelium (Johnson et al., 1977) there is
evidence for cell coupling (Loewenstein, 1967) and gap junctions (Revel and
Goodenough, 1970; Revel and Mann, unpublished) in relatively primitive phyla
such as the Porifera and the Mesozoa (Revel, Levy and Wang, unpublished).
This brief review will attempt to summarize recent developments in our
understanding of the morphological organization of gap junctions, their
formation and disappearance and to discuss some of the ideas about the
function of these ubiquitous structures.
Age-Friendly Communities and Cultural Pluralism: Examining Saskatoon’s Chinese-Canadian Social Enclave
Authors: Herman Lindsay , Walker Ryan , Rosenberg Mark
Published: June 2020

This article uses findings from qualitative interviews to examine the experiences of members of Saskatoon’s Chinese-Canadian older-adult community in terms of their realities of aging and access to important geriatric resources. Promoting an understanding of both group experience and a broader conceptualization of age-friendly development, we argue that the notion and implications of a spatial ethnic enclave are replaced in the Saskatoon context by asocial enclave.This network of social support is evident in Chinese-Canadian older adults’ access to housing, recreation, transportation, and health services. The article concludes with lessons learned that would help enhance culturally pluralistic age-friendly development. This work underlines the significance of social capital development within more marginalized older-adult communities, both as a reaction to outside discrimination, and as a means of ensuring healthy and inclusive community aging.
The Scramble for Africa Reloaded? Portugal, European Colonial Claims and the Distribution of Colonies in the 1930s
Authors: Gonçalves Márcia
Published: June 2020

Situating itself at the crossroads of colonial history, international history and European history, this article examines the movement for colonial appeasement and the redistribution of African colonies in the 1930s from a frequently overlooked viewpoint: Portugal and its empire. Even though Portugal was not a principal actor in the discussion of colonial redistribution, the Portuguese empire was placed at the centre of these debates as a subject to be discussed. The article demonstrates that the great powers’ perception of Portugal as an inadequate colonial power was central to their strategy of colonial redistribution in an international context that espoused guarantees of territorial integrity to great and small states alike. In addition, it shows how Portugal entered the debate on colonial appeasement to promote a rhetoric of victimisation and bolster support for the dictatorship.
Influence of pre-schooler and parent nutrition education on carotenoid levels of Mexican-heritage children
Authors: Horowitz Marcel , Kaiser Lucia L. , Manzo Rosa D , Aguilera Albert , Diaz Rios L. Karina , Macias Karina
Published: June 2020

Objective:

To determine the mediating effect of direct preschool and parent nutrition education on changes in skin carotenoids scores over 2 years in children of Mexican heritage.

Design:

In a quasi-experimental, community-based study, two school districts were randomly assigned to either a comparison group (parent workshops unrelated to nutrition) or a childhood obesity prevention intervention group which included nutrition education at family nights for parents and at school for children. Changes in skin carotenoid intensity scores (diffCAROT, year 2015 minus 2013) were measured in children as a proxy for fruit and vegetable consumption using Resonance Raman Spectroscopy.

Setting:

Two rural, low-income, school districts from a county in California’s Central Valley.

Participants:

316 Mexican heritage families with children aged 3–8 years.

Results:

Intervention group children improved over 2 years in skin carotenoid scores relative to comparison group children (diffCAROT mean +1419 (sd 9540) v. –3473 (sd 9272), P = 0·0001). Parent attendance at nutrition education classes partially mediated the intervention effect on diffCAROT (P = 0·02). Controlling for child’s age and other covariates, participation in preschool during the study had a significant positive effect on diffCAROT among intervention children compared with controls (P < 0·03), whereas no significant difference by group was observed among those not enrolled in preschool or already enrolled in elementary school.

Conclusions:

Programmes that combine direct parent and preschool nutrition education may be effective in low-income Mexican heritage families to improve children’s intake of fruit and vegetables.
Life Beyond 1MeV
Authors: Westmacott K.H.
Published: June 2020

Life beyond 1MeV – like life after 40 – is not too different unless one
takes advantage of past experience and is receptive to new opportunities. At
first glance, the returns on performing electron microscopy at voltages
greater than 1MeV diminish rather rapidly as the curves which describe the
well-known advantages of HVEM often tend towards saturation. However, in a
country with a significant HVEM capability, a good case can be made for
investing in instruments with a range of maximum accelerating voltages. In
this regard, the 1.5MeV KRATOS HVEM being installed in Berkeley will
complement the other 650KeV, 1MeV, and 1.2MeV instruments currently
operating in the U.S. One other consideration suggests that 1.5MeV is an
optimum voltage machine – Its additional advantages may be purchased for not
much more than a 1MeV instrument. On the other hand, the 3MeV HVEM's which
seem to be operated at 2MeV maximum, are much more expensive.
Low Dose Electron Diffraction Study of Rabbit Fc Fragment
Authors: Chiu W. , Robinson J.
Published: June 2020

An immunoglobulin molecule is a serum glycoprotein synthesized by
vertebrates as antibodies against various antigens. The antigen binding
domain lies in the Fab fragment containing the amino terminal while the
effector function resides in the Fc fragment containing the carboxyl
terminal. The Fab fragment can be separated from the Fc fragment by
proteolytic treatment with papain (1). The structures of the gamma
immunoglobulin and of the Fab fragment from various sources have been
determined by x-ray crystallographic technique (2). The x-ray
crystallographic study of a human Fc fragment at 3.5 Å shows that the Fc
structure has an approximate shape of a “mickey mouse.” (2) A preliminary
investigation of the rabbit Fc fragment by x-ray diffraction method was
reported previously (3). We have used a similar method as Poljak and
coworkers to crystallize the rabbit Fc fragment by dialysis against dilute
phosphate buffer at neutral PH. A milky solution can normally be observed
after 24 hours of dialysis. However, the crystal thickness was found to
increase as a function of its age. The two dimensional size of the freshly
prepared crystal is well over 1 μm2 which may make it
suitable for low dose electron diffraction analysis.
Reconstruction of Chitin-Protein Complexes Using Correlation Averaging
Methods: Ovipositor of the Ichneumon Fly

Megarhyssa
Authors: Germinario L. T. , Blackwell J. , Frank J.
Published: June 2020

This report describes the use of digital correlation and averaging
methods 1,2 for the reconstruction of high dose
electron micrographs of the chitin-protein complex from
Megarhyssa ovipositor.

Electron microscopy of uranyl acetate stained insect cuticle has
demonstrated a hexagonal array of unstained chitin monofibrils, 2.4−3.0 nm
in diameter, in a stained protein matrix3,4. Optical
diffraction Indicated a hexagonal lattice with a = 5.1-8.3
nm3 A particularly well ordered complex is found in
the ovipositor of the ichneumon fly
Megarhyssa: the small angle x-ray data
gives a = 7.25 nm, and the wide angle pattern shows that the protein
consists of subunits arranged in a 61 helix, with an
axial repeat of 3.06 nm5.
Digital Image Processing of STEM Images of Tobacco Mosaic Virus
(TMV)
Authors: Kirkland E. J. , Freeman W. T. , Ohtsuki M. , Isaacson M. S. , Siegel B. M.
Published: June 2020

Low radiation doses are necessary to prevent undue specimen damage when
recording electron micrographs. Unfortunately, such a requirement results in
low signal to noise in the image which may limit the effective resolution.
Digital image processing techniques have been used to increase the effective
signal to noise and enhance scanning transmission electron micrographs of
TMV. The original micrographs were taken on the University of Chicago STEM
[1] using the annular dark field detector signal and processed on computer
facilities at Cornell University. The specimen consists of negatively
stained (1% uranyl acetate) particles of TMV (intact virus) as described in
[2]. The electron probe diameter was ˜2.5Å and the total dose to the
specimen was ˜11/Å2.
Software Expansions for a Stem Fast Digital Data Acquisition
System
Authors: Butler J. H.
Published: June 2020

The basic components of our Fast Digital Data Acquisition System (FDDAS)
have been described elsewhere. The fully programmable nature of each FDDAS
hardware device along with the independent modular structure of the
associated software has provided the desired flexibility for several
software expansions. Because of their complexity, certain routines, such as
selectable dual-channel test pattern generation and the joystick service
routine, constitute independent modules in their own right. Other routines,
for image data manipulation and real time computer control of scan
parameters, can be written in assembly language or FORTRAN and separately
compiled and included in a software library for easy inclusion or deletion
without modification of major data transfer modules.
Three-Dimensional Reconstruction of a Mitochondrion Based on a Thick
Section Tilt Series Recorded in the HVEM
Authors: Frank J. , Turner J. N. , Marko M. , Asmus K. , Parsons D. F.
Published: June 2020

A three-dimensional reconstruction of a mitochondrion has been made
based on a tilt series recorded in our HVEM. Fig. 1 is a low magnification
view of an axon in cat motor cortex showing the general cellular
ultrastructure and the mitochondrion used in the reconstruction. Fig. 2
shows five of the images of the mitochondrion recorded over the angular
range +27° to −30°. A total of nine images were used in the reconstruction.
The brain of a normal adult cat was fixed by aortic perfusion using 4%
buffered paraformaldehyde with sucrose at 4°C for 15 min. The brain was then
removed and fixed overnight in glut-eraldehyde. Postfixation was carried out
in 1% oso4 for one hour, and the sample was then
dehydrated and embedded in epon. Half micron sections were stained in
aqueous uranyl acetate for two hours at 50°C followed by Reynolds lead
citrate for one hour at room temperature. The tilt series was recorded in
our AEI EM7 at 1.0MeV using the Swann (1) double tilt stage.
A Temperature-Controlled High Resolution Stage
Authors: Listvan M. , Crewe A.V. , Mankawich W.
Published: June 2020

A high resolution temperature controlled stage capable of maintaining
temperatures in the range of +100°C has been designed and constructed for
the 100 keV scanning transmission electron microscope
(STEM)1. This work will facilitate the continuing
studies of the motion of atoms on surfaces. The interaction of atoms with
surfaces can then be studied by directly observing their motion as a
function of temperature to measure the diffusion coefficients and activation
energies. Some preliminary measurements have been made, but more work should
be done in this area.

Some operating features of the thermal stage are:

It is designed as a heating or cooling stage with a
temperature range of ±100°C accessible by a simple adjustment of
the external heat exchanger.

The specimen stage is designed to compensate for thermal
drift.

A non-magnetic thermocouple is attached to the specimen
stage to permit dynamic temperature measurement.

The thermal block does not mechanically couple to the
present high resolution room temperature specimen stages,
insuring independent checks on the stability of the instrument
and the thermal stage.
Progress in the Development of a Field Ionization Scanning Transmission
Ion Microscope
Authors: Levi-Setti R. , Fox T. R. , Lam K.
Published: June 2020

The construction of a Scanning Transmission Ion Microscope (STIM) using
a field ionization (FI) source of H ions was initiated in 1971 by R.
Levi-Setti at the University of Chicago. A demonstration of feasibility was
reported in 1974 [1]. The basic imaging capabilities of the Chicago STIM and
its use for non-destructive imaging were demonstrated at a resolution
approaching 100 nm [2-5]. Subsequent development of the STIM concentrated on
the exploration of new contrast mechanisms and its use as a quantitative
instrument for physics and biology.

The present STIM is describe in [6,7]. An electrostatic gun lens
accelerates the field-ionized ions to 50-70 keV and images the point source
into a small probe in the specimen plane. A ratio of 9 between the probe
voltage and the ionization voltage will focus the beam 10 cm from the lens
exit. An exit aperture of 30 μm defines a beam semiangle of 0.15 mrad at the
specimen. The theoretical minimum probe radius is limited by chromatic
aberration to (6.5-e△V) nm, where e△V is the energy spread of the source in
eV. We use an electrostatic scanning and stigmator system. The gun and
specimen chambers are differentially pumped. A 90° sector double-focussing
magnetic spectrometer is used to analyze the transmitted beam. Its
acceptance semiangle is 10 mrad, and the energy resolution is 0.1%.
Field Emission Sem Using Strongly Excited Objective Lens
Authors: Tamura N. , Saito H. , Ohyama J. , Aihara R. , Kabaya A.
Published: June 2020

To observe surface details of the specimen without charge-up and damage,
low accelerating voltage is suitable. When the accelerating voltage is
lowered, the probe diameter becomes large due to the decrease of the
brightness of the electron source and to the increase of the lens aberration
effect.

In this study, we conbined the high brightness electron source and the
low aberration lens. Fig. 1 shows the schematic diagram of the electron
optical column.
Validity and Accuracy of Quantitative Elemental Measurements with Core
Loss Signals in EELS
Authors: Trebbia P. , Colliex C.
Published: June 2020

The basic formula for quantitative elemental measurements by use of core
loss signals in EELS has been proposed by Egerton and a rather complete
discussion can be found in : Sc (α,Δ) =
N.Io (α,Δ).σc(α,Δ)

This formula enables to measure the partial cross section for a given
edge when applied to standards of known composition and thickness, and the
results are to be compared with a priori calculations of the corresponding
oscillator strengths in atomic models. With the knowledge of these data, one
can then estimate the number of atoms contained within the probed volume,
which are responsible of the occurrence of the signal. The above formula
constitutes in fact an approximation to take into account multiple
scattering events which partially transfer the characteristic signal
distribution outside the angular α and energetic Δ parameters of
collection.
Characterization of Some 3d Transition Metal Oxides through Core Loss
Electron Energy Loss Spectroscopy
Authors: Grunes L. A.
Published: June 2020

Electron Energy Loss Spectroscopy (EELS) is a useful technique for
chemical microanalysis in the electron microscope. In particular, medium
resolution (˜leV) measurements of core losses involving ionization of the
tightly bound inner shell electrons reveal fine structure which identify
both the core atom and the neighboring chemical environment. The transition
metals of the third period possess narrow partly filled d-bands which give
rise to striking magnetic and electronic properties of technological
importance.
Measurement of Crack Growth Rates By use of the SEM
Authors: Brown R.
Published: June 2020

Often, measurement of the growth of short cracks with the number of
cycles is required during fatigue testing. Optical examination is limited to
useful magnification of ×1000 and the distinction between slip and a short
crack is extremely difficult to make. Electrical potential drop measurement
is not sufficiently sensitive to determine the start, on a microscopic
level, of a short single crack. In situ observation of fatigue in the SEM
presents enviromental problems. However plastic replicas taken from a smooth
specimen surface during fatigue can be imaged in the SEM to produce
extremely accurate short surface crack measurements. The initiation of a
crack can be very accurately determined and surface crack lengths as short
as 2μm can be measured. The technique allows a comparison between
macroscopic crack growth data and data produced from short cracks, 2 to
300μm in length. As example of the process has been carried out for
Ti-6A1-4V.
Effect of Magnetic Fields on the Structure of Electrodeposited
Copper
Authors: Dash J. , Housen K.
Published: June 2020

It was shown in previous work that magnetic fields applied during
electrodeposition of copper improve the uniformity of the
deposits.1 More recently it was reported that this
method has been developed into a practical process for through-hole plating
of circuit boards.2 This process prevents uneven
plating in the holes, and the properties of the platings are reported to be
excellent, although no specific properties are given.2
We are currently studying the structure and properties of copper deposits as
a function of magnetic field strength applied during the electrodeposition
process.