1,253 research outputs found
Bipartite Minors
We introduce a notion of bipartite minors and prove a bipartite analog of
Wagner's theorem: a bipartite graph is planar if and only if it does not
contain as a bipartite minor. Similarly, we provide a forbidden minor
characterization for outerplanar graphs and forests. We then establish a
recursive characterization of bipartite -Laman graphs --- a certain
family of graphs that contains all maximal bipartite planar graphs.Comment: 9 page
One-stop border posts in East Africa:State encounters of the fourth kind
Across Africa, One-Stop Border Posts are being rolled out as part of a continental/ regional integration agenda that seeks to facilitate the movement of people and goods. This article focuses on four OSBPs in East Africa and addresses the question, firstly, of how far they make a break with entrenched operational patterns within government bureaucracies, and secondly whether they represent a distinct type of border management regime? The article finds that while there has been progress on data sharing in Customs, the construction and management of OSBPs reflects the persistence of distinct institutional cultures within each country. Moreover, working practices involve practical workarounds which belie notions of a paperless border. Secondly, the article finds that OSBPs are unlike other border crossings and share some features with airports and seaports in that they have been designed to handle both cargo and people. But they differ in that they are not heavily securitized and represent co-produced spaces of interaction in which transporters and members of the surrounding community have helped to shape the organizational patterns. The outcomes fuse an official ideology of service, everyday bureaucratic practice and local understandings of ownership
Does Siri Have a Soul? Exploring Voice Assistants Through Shinto Design Fictions
It can be difficult to critically reflect on technology that has become part
of everyday rituals and routines. To combat this, speculative and fictional
approaches have previously been used by HCI to decontextualise the familiar and
imagine alternatives. In this work we turn to Japanese Shinto narratives as a
way to defamiliarise voice assistants, inspired by the similarities between how
assistants appear to 'inhabit' objects similarly to kami. Describing an
alternate future where assistant presences live inside objects, this approach
foregrounds some of the phenomenological quirks that can otherwise easily
become lost. Divorced from the reality of daily life, this approach allows us
to reevaluate some of the common interactions and design patterns that are
common in the virtual assistants of the present.Comment: 11 pages, 2 images. To appear in the Extended Abstracts of the 2020
CHI Conference on Human Factors in Computing Systems (CHI '20
Molecular cytogenetic characterisation of a novel de novo ring chromosome 6 involving a terminal 6p deletion and terminal 6q duplication in the different arms of the same chromosome
Background
Ring chromosome 6 is a rare sporadic chromosomal abnormality, associated with extreme variability in clinical phenotypes. Most ring chromosomes are known to have deletions on one or both chromosomal arms. Here, we report an atypical and unique ring chromosome 6 involving both a distal deletion and a distal duplication on the different arms of the same chromosome.
Case presentation
In a patient with intellectual disability, short stature, microcephaly, facial dysmorphology, congenital heart defects and renovascular disease, a ring chromosome 6 was characterised using array-CGH and dual-colour FISH. The de-novo ring chromosome 6 involved a 1.8 Mb terminal deletion in the distal short arm and a 2.5 Mb duplication in the distal long arm of the same chromosome 6. This results in monosomy for the region 6pter to 6p25.3 and trisomy for the region 6q27 to 6qter. Analysis of genes in these chromosomal regions suggests that haploinsufficiency for FOXC1 and GMDS genes accounts for the cardiac and neurodevelopmental phenotypes in the proband. The ring chromosome 6 reported here is atypical as it involves a unique duplication of the distal long arm. Furthermore, the presence of renovascular disease is also a unique feature identified in this patient.
Conclusion
To the best of our knowledge, a comparable ring chromosome 6 involving both a distal deletion and duplication on different arms has not been previously reported. The renovascular disease identified in this patient may be a direct consequence of the described chromosome rearrangement or a late clinical presentation in r(6) cases. This clinical finding may further support the implicated role of FOXC1 gene in renal pathology.peer-reviewe
Sub-series and sub-epochs are informal units and should continue to be omitted from the International Chronostratigraphic Chart
In June 2016 the Paleogene, Neogene, and Quaternary subcommissions (ISPS, SNS, SQS) of the International Commission on Stratigraphy (ICS) voted on whether to formalize sub-series and their geochronologic equiva-lents, sub-epochs. The vote required a 60 percent major-ity for the proposal to be forwarded to the ICS for further consideration. That majority was not achieved, albeit by a narrow margin, hence sub-series and sub-epochs are currently to be regarded as informal, and if used should carry a lower case modifier, as in lower Miocene and early Pleistocene. To accompany the vote, those who favoured continuation of informal usage were asked to prepare a short summary of the main arguments in support of their viewpoint, as were the proponents of the formalization case. Although this statement was not originally intended for publication, it is reproduced here at the request of the Former Chair of the ICS, so as to put it on record
Hanseniaspora uvarum Attracts Drosophila suzukii (Diptera: Drosophilidae) With High Specificity
Since the early phase of the intercontinental dispersal of Drosophila suzukii (Matsumura) (Diptera: Drosophilidae), fermentation baits have been used for monitoring. Self-made lures and commercial products are often based on wine and vinegar. From an ecological perspective, the formulation of these baits is expected to target especially vinegar flies associated with overripe fruit, such as Drosophila melanogaster (Meigen) (Diptera: Drosophilidae). Hanseniaspora uvarum (Niehaus) (Ascomycota: Saccharomyceta) is a yeast closely associated with D. suzukii and fruit, and furthermore attractive to the flies. Based on this relation, H. uvarum might represent a suitable substrate for the development of lures that are more specific than vinegar and wine. In the field, we therefore, compared H. uvarum to a commercial bait that was based on vinegar and wine with respect to the number of trapped D. suzukii relative to other drosophilids and arthropods. Trap captures were higher with the commercial bait but specificity for D. suzukii was greater with H. uvarum. Moreover, H. uvarum headspace extracts, as well as a synthetic blend of H. uvarum volatiles, were assayed for attraction of D suzukii in a wind tunnel and in the field. Headspace extracts and the synthetic blend induced strong upwind flight in the wind tunnel and confirmed attraction to H. uvarum volatiles. Furthermore, baited with H. uvarum headspace extract and a drowning solution of aqueous acetic acid and ethanol, 74% of field captured arthropods were D. suzukii. Our findings suggest that synthetic yeast headspace formulations might advance the development of more selective monitoring traps with reduced by-catch
Introducing the GWmodel R and python packages for modelling spatial heterogeneity
In the very early developments of quantitative geography, statistical techniques were
invariably applied at a ‘global’ level, where moments or relationships were assumed constant
across the study region (Fotheringham and Brunsdon, 1999). However, the world is not an
“average” space but full of variations and as such, statistical techniques need to account for
different forms of spatial heterogeneity or non-stationarity (Goodchild, 2004). Consequently,
a number of local methods were developed, many of which model non- stationarity
relationships via some regression adaptation. Examples include: the expansion method
(Casetti, 1972), random coefficient modelling (Swamy et al., 1988), multilevel modelling
(Duncan and Jones, 2000) and space varying parameter models (Assunção, 2003).
One such localised regression, geographically weighted regression (GWR) (Brunsdon et
al., 1996) has become increasingly popular and has been broadly applied in many disciplines
outside of its quantitative geography roots. This includes: regional economics, urban and
regional analysis, sociology and ecology. There are several toolkits available for applying
GWR, such as GWR3.x (Charlton et al., 2007); GWR 4.0 (Nakaya et al., 2009); the GWR
toolkit in ArcGIS (ESRI, 2009); the R packages spgwr (Bivand and Yu, 2006) and gwrr
(Wheeler, 2011); and STIS (Arbor, 2010). Most focus on the fundamental functions of GWR
or some specific issue - for example, gwrr provides tools to diagnose collinearity.
As a major extension, we report in this paper the development an integrated framework for
handling spatially varying structures, via a wide range of geographically weighted (GW)
models, not just GWR. All functions are included in an R package named GWmodel, which
is also mirrored with a set of GW modelling tools for ESRI’s ArcGIS written in Python
Germanium-on-silicon Waveguides for Mid-infrared Photonic Sensing Chips
Germanium-on-silicon rib waveguides are modelled, fabricated and characterized with a novel near-field infrared spectroscopy technique that allows on-chip investigation of the waveguide losses at 5.8 μm wavelength
Peripheral urbanism in Africa:Border towns and twin towns in Africa
There has been a proliferation of research on Africa’s borderlands over the past decade, which reflects their centrality in regional systems of trade and the rapid growth of border settlements. The development of twin towns/cities at the border, which has attracted the interest of scholars in other regions of the world, has been a distinctive feature of Africa as well. This paper examines some of the particularities of peripheral urbanism in Africa, whilst seeking to avoid a resort to continental exceptionalism. It begins by tracing some broad patterns before homing in on two sets of case-studies along the Uganda/Kenya and Ghana/Togo borders. The paper argues, firstly, for the enduring importance of colonial infrastructural investments and the policy choices that were made after independence. Secondly, it highlights the markedly different variations of scale, ranging from the border capitals of Kinshasa and Brazzaville at one end of the spectrum, through growing towns like Busia-Uganda and Busia- Kenya, to a multiplicity of smaller border settlements at the other end. Thirdly, the paper argues that administrative logics and trade dynamics have been the main drivers in the expansion of twin cities/towns, although the flight of populations from insecurity have also played a significant role in the Great Lakes region and in West-Central Africa. Finally, the paper points to a feature that has been identified in other regions as well, notably the often marked asymmetries between border settlements, which reflects the influence of deeper historical trajectories and contemporary patterns of trade and population movement alike
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