Tiling, spectrality and aperiodicity of connected sets

Let $\Omega\subset \mathbb{R}^d$ be a set of finite measure. The periodic tiling conjecture suggests that if $\Omega$ tiles $\mathbb{R}^d$ by translations then it admits at least one periodic tiling. Fuglede's conjecture suggests that $\Omega$ admits an orthogonal basis of exponential functions if and only if it tiles $\mathbb{R}^d$ by translations. Both conjectures are known to be false in sufficiently high dimensions, with all the so-far-known counterexamples being highly disconnected. On the other hand, both conjectures are known to be true for convex sets. In this work we study these conjectures for connected sets. We show that the periodic tiling conjecture, as well as both directions of Fuglede's conjecture are false for connected sets in sufficiently high dimensions.Comment: 20 pages, 8 figure

Community structure and patterns of scientific collaboration in Business and Management

This is the author's accepted version of this article deposited at arXiv (arXiv:1006.1788v2 [physics.soc-ph]) and subsequently published in Scientometrics October 2011, Volume 89, Issue 1, pp 381-396. The final publication is available at link.springer.com http://link.springer.com/article/10.1007%2Fs11192-011-0439-1Author's note: 17 pages. To appear in special edition of Scientometrics. Abstract on arXiv meta-data a shorter version of abstract on actual paper (both in journal and arXiv full pape

Communities and patterns of scientific collaboration in Business and Management

This is the author's accepted version of this article deposited at arXiv (arXiv:1006.1788v2 [physics.soc-ph]) and subsequently published in Scientometrics October 2011, Volume 89, Issue 1, pp 381-396. The final publication is available at link.springer.com http://link.springer.com/article/10.1007%2Fs11192-011-0439-1Author's note: 17 pages. To appear in special edition of Scientometrics. Abstract on arXiv meta-data a shorter version of abstract on actual paper (both in journal and arXiv full pape

The evolution of health policy guidelines for assisted reproduction in the Republic of Ireland, 2004-2009

This analysis reports on Irish regulatory policies for in vitro fertilisation (IVF) from 2004-2009, in the context of membership changes within the Medical Council of Ireland. To achieve this, the current (2009) edition of the Guide to Professional Conduct & Ethics was compared with the immediately preceding version (2004). The statutory composition of the Medical Council from 2004-2009 was also studied. Content analysis of the two editions identified the following differences: 1) The 2004 guide states that IVF "should only be used after thorough investigation has failed to reveal a treatable cause of the infertility", while the 2009 guide indicates IVF "should only be used after thorough investigation has shown that no other treatment is likely to be effective"; 2) The 2004 stipulation stating that fertilized ovum (embryo) "must be used for normal implantation and must not be deliberately destroyed" is absent from the 2009 guidelines; 3) The option to donate "unused fertilised ova" (embryos) is omitted from the 2009 guidelines; 4) The 2009 guidelines state that ART should be offered only by "suitably qualified professionals, in appropriate facilities, and according to the international best practice"; 5) The 2009 guidelines introduce criteria that donations as part of a donor programme should be "altruistic and non-commercial". These last two points represent original regulatory efforts not appearing in the 2004 edition. The Medical Practitioners Act 2007 reduced the number of physicians on the Medical Council to 6 (of 25) members. The ethical guidelines from 2004 preceded this change, while the reconstituted Medical Council published the 2009 version. Between 2004 and 2009, substantial modifications in reproductive health policy were incorporated into the Medical Council's ethical guidelines. The absence of controlling Irish legislation means that patients and IVF providers in Ireland must rely upon these guidelines by default. Our critique traces the evolution of public policy on IVF during a time when the membership of the Medical Council changed radically; reduced physician contribution to decision-making was associated with diminished protection for IVF-derived embryos in Ireland. Considerable uncertainty on IVF practice in Ireland remains

COVID‐19, nationalism, and the politics of crisis: A scholarly exchange

In this article, several scholars of nationalism discuss the potential for the COVID‐19 pandemic to impact the development of nationalism and world politics. To structure the discussion, the contributors respond to three questions: (1) how should we understand the relationship between nationalism and COVID‐19; (2) will COVID‐19 fuel ethnic and nationalist conflict; and (3) will COVID‐19 reinforce or erode the nation‐state in the long run? The contributors formulated their responses to these questions near to the outset of the pandemic, amid intense uncertainty. This made it acutely difficult, if not impossible, to make predictions. Nevertheless, it was felt that a historically and theoretically informed discussion would shed light on the types of political processes that could be triggered by the COVID‐19 pandemic. In doing so, the aim is to help orient researchers and policy‐makers as they grapple with what has rapidly become the most urgent issue of our times

In utero exposure to low doses of environmental pollutants disrupts fetal ovarian development in sheep

Epidemiological studies of the impact of environmental chemicals on reproductive health demonstrate consequences of exposure but establishing causative links requires animal models using ‘real life’ in utero exposures. We aimed to determine whether prolonged, low-dose, exposure of pregnant sheep to a mixture of environmental chemicals affects fetal ovarian development. Exposure of treated ewes (n = 7) to pollutants was maximized by surface application of processed sewage sludge to pasture. Control ewes (n = 10) were reared on pasture treated with inorganic fertilizer. Ovaries and blood were collected from fetuses (n = 15 control and n = 8 treated) on Day 110 of gestation for investigation of fetal endocrinology, ovarian follicle/oocyte numbers and ovarian proteome. Treated fetuses were 14% lighter than controls but fetal ovary weights were unchanged. Prolactin (48% lower) was the only measured hormone significantly affected by treatment. Treatment reduced numbers of growth differentiation factor (GDF9) and induced myeloid leukaemia cell differentiation protein (MCL1) positive oocytes by 25–26% and increased pro-apoptotic BAX by 65% and 42% of protein spots in the treated ovarian proteome were differently expressed compared with controls. Nineteen spots were identified and included proteins involved in gene expression/transcription, protein synthesis, phosphorylation and receptor activity. Fetal exposure to environmental chemicals, via the mother, significantly perturbs fetal ovarian development. If such effects are replicated in humans, premature menopause could be an outcome

Nowhere to go: How stigma limits the options of female drug users after release from jail

<p>Abstract</p> <p>Background</p> <p>Drug and alcohol using women leaving prison or jail face many challenges to successful re-integration in the community and are severely hampered in their efforts by the stigma of drug or alcohol use compounded by the stigma of incarceration.</p> <p>Methods</p> <p>This qualitative study is based on individual semi-structured interviews and focus groups with 17 women who had recently left jail about the challenges they faced on reentry.</p> <p>Results</p> <p>Our analysis identified three major themes, which are related by the overarching influence of stigma: survival (jobs and housing), access to treatment services, and family and community reintegration.</p> <p>Conclusion</p> <p>Stigma based on drug use and incarceration works to increase the needs of women for health and social services and at the same time, restricts their access to these services. These specific forms of stigma may amplify gender and race-based stigma. Punitive drug and social policies related to employment, housing, education, welfare, and mental health and substance abuse treatment make it extremely difficult for women to succeed.</p

Brexit and Scotland:Between Two Unions

This article addresses the territorial dimension of the Brexit referendum and its consequences, especially with respect to devolution and the independence debate within Scotland. The convincing Scottish majority vote for Remain alongside the UK vote to leave the EU has exposed the difficulties in reconciling rival self-determination claims. The Brexit vote has also raised again the issue of Scotland’s place within the UK, and for some justifies reconsideration of the decision the Scottish electorate made to remain within the UK by rejecting independence in 2014. The article considers the explanations for the Remain vote in Scotland, and the reactions of the Scottish and UK Governments to the competing preferences north and south of the border. It argues that the ‘one nation’ nationalist rhetoric of the UK Government in the aftermath of the vote is at odds with the plurinational character of the United Kingdom. It critically examines the effects of the Brexit process to date on the influence and constitutional authority of the devolved institutions, while pointing to the challenges that would confront advocates of independence were that issue to re-emerge as the Brexit process unfolds

Proliferating Cell Nuclear Antigen (PCNA) Regulates Primordial Follicle Assembly by Promoting Apoptosis of Oocytes in Fetal and Neonatal Mouse Ovaries

Primordial follicles, providing all the oocytes available to a female throughout her reproductive life, assemble in perinatal ovaries with individual oocytes surrounded by granulosa cells. In mammals including the mouse, most oocytes die by apoptosis during primordial follicle assembly, but factors that regulate oocyte death remain largely unknown. Proliferating cell nuclear antigen (PCNA), a key regulator in many essential cellular processes, was shown to be differentially expressed during these processes in mouse ovaries using 2D-PAGE and MALDI-TOF/TOF methodology. A V-shaped expression pattern of PCNA in both oocytes and somatic cells was observed during the development of fetal and neonatal mouse ovaries, decreasing from 13.5 to 18.5 dpc and increasing from 18.5 dpc to 5 dpp. This was closely correlated with the meiotic prophase I progression from pre-leptotene to pachytene and from pachytene to diplotene when primordial follicles started to assemble. Inhibition of the increase of PCNA expression by RNA interference in cultured 18.5 dpc mouse ovaries strikingly reduced the apoptosis of oocytes, accompanied by down-regulation of known pro-apoptotic genes, e.g. Bax, caspase-3, and TNFα and TNFR2, and up-regulation of Bcl-2, a known anti-apoptotic gene. Moreover, reduced expression of PCNA was observed to significantly increase primordial follicle assembly, but these primordial follicles contained fewer guanulosa cells. Similar results were obtained after down-regulation by RNA interference of Ing1b, a PCNA-binding protein in the UV-induced apoptosis regulation. Thus, our results demonstrate that PCNA regulates primordial follicle assembly by promoting apoptosis of oocytes in fetal and neonatal mouse ovaries