Fast Algorithm and Implementation of Dissimilarity Self-Organizing Maps

In many real world applications, data cannot be accurately represented by vectors. In those situations, one possible solution is to rely on dissimilarity measures that enable sensible comparison between observations. Kohonen's Self-Organizing Map (SOM) has been adapted to data described only through their dissimilarity matrix. This algorithm provides both non linear projection and clustering of non vector data. Unfortunately, the algorithm suffers from a high cost that makes it quite difficult to use with voluminous data sets. In this paper, we propose a new algorithm that provides an important reduction of the theoretical cost of the dissimilarity SOM without changing its outcome (the results are exactly the same as the ones obtained with the original algorithm). Moreover, we introduce implementation methods that result in very short running times. Improvements deduced from the theoretical cost model are validated on simulated and real world data (a word list clustering problem). We also demonstrate that the proposed implementation methods reduce by a factor up to 3 the running time of the fast algorithm over a standard implementation

Homozygous single base deletion in TUSC3 causes intellectual disability with developmental delay in an Omani family

Intellectual disability (ID) is the term used to describe a diverse group of neurological conditions with congenital or juvenile onset, characterized by an IQ score of less than 70 and difficulties associated with limitations in cognitive function and adaptive behavior. The condition can be inherited or caused by environmental factors. The genetic forms are heterogeneous, with mutations in over 500 known genes shown to cause the disorder. We report a consanguineous Omani family in which multiple individuals have ID and developmental delay together with some variably present features including short stature, microcephaly, moderate facial dysmorphism, and congenital malformations of the toes or hands. Homozygosity mapping combined with whole exome next generation sequencing identified a novel homozygous single base pair deletion in TUSC3, c.222delA, p.R74 fs. The mutation segregates with the disease phenotype in a recessive manner and is absent in 60,706 unrelated individuals from various disease-specific and population genetic studies. TUSC3 mutations have been previously identified as causing either syndromic or non-syndromic ID in patients from France, Italy, Iran and Pakistan. This paper supports the previous clinical descriptions of the condition caused by TUSC3 mutations and describes the seventh family with mutations in this gene, thus contributing to the genetic spectrum of mutations. This is the first report of a family from the Arabian peninsula with this form of ID

Subitizing with Variational Autoencoders

Numerosity, the number of objects in a set, is a basic property of a given visual scene. Many animals develop the perceptual ability to subitize: the near-instantaneous identification of the numerosity in small sets of visual items. In computer vision, it has been shown that numerosity emerges as a statistical property in neural networks during unsupervised learning from simple synthetic images. In this work, we focus on more complex natural images using unsupervised hierarchical neural networks. Specifically, we show that variational autoencoders are able to spontaneously perform subitizing after training without supervision on a large amount images from the Salient Object Subitizing dataset. While our method is unable to outperform supervised convolutional networks for subitizing, we observe that the networks learn to encode numerosity as basic visual property. Moreover, we find that the learned representations are likely invariant to object area; an observation in alignment with studies on biological neural networks in cognitive neuroscience

Atmospheric correction of visible to middle-infrared EOS-MODIS data over land surfaces: Background, operational algorithm and validation

The NASA moderate resolution imaging spectroradiometer (MODIS) instrument will provide a global and improved source of information for the study of land surfaces with a spatial resolution of up to 250 m

Modulating attentional load affects numerosity estimation: evidence against a pre-attentive subitizing mechanism

Traditionally, the visual enumeration of a small number of items (1 to about 4), referred to as subitizing, has been thought of as a parallel and pre-attentive process and functionally different from the serial attentive enumeration of larger numerosities. We tested this hypothesis by employing a dual task paradigm that systematically manipulated the attentional resources available to an enumeration task. Enumeration accuracy for small numerosities was severely decreased as more attentional resources were taken away from the numerical task, challenging the traditionally held notion of subitizing as a pre-attentive, capacity-independent process. Judgement of larger numerosities was also affected by dual task conditions and attentional load. These results challenge the proposal that small numerosities are enumerated by a mechanism separate from large numerosities and support the idea of a single, attention-demanding enumeration mechanism

Functional roles of the factor VIII B domain

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/74800/1/j.1365-2516.2009.02026.x.pd

Risk factors of osteoporosis in healthy Moroccan men

<p>Abstract</p> <p>Background</p> <p>Although not as common as in women, osteoporosis remains a significant health care problem in men. Data concerning risk factors of osteoporosis are lacking for the male Moroccan population. The objective of the study was to identify some determinants associated to low bone mineral density in Moroccan men.</p> <p>Methods</p> <p>a sample of 592 healthy men aged 20-79 years was recruited from the area of Rabat, the capital of Morocco. Measurements were taken at the lumbar spine and proximal femurs using DXA (Lunar Prodigy Vision, GE). Biometrical, clinical, and lifestyle determinants were collected. Univariate, multivariate, and logistic regression analyses were performed.</p> <p>Results</p> <p>the mean (SD) age of the patients was 49 (17.2) years old. The prevalence of osteoporosis and osteopenia were 8.7% and 52.8%, respectively. Lumbar spine and hip BMD correlated significantly with age, weight and BMI. When comparing the subjects according to the WHO classification, significant differences were revealed between the three groups of subjects for age, weight and BMI, prevalence of low calcium intake and low physical activity. The multiple regression analysis found that only age, BMI, and high coffee consumption were independently associated to the osteoporotic status.</p> <p>Conclusion</p> <p>ageing and low BMI are the main risk factors associated with osteoporosis in Moroccan men.</p

Correction to: China’s health assistance to Africa: opportunism or altruism?

Please note that following publication of the original article [1], one of the authors has flagged that the abbreviations section lists “BRIC” as “Britain, Russia, India and China”

A qualitative study of enablers and barriers influencing the incorporation of social accountability values into organisational culture: a perspective from two medical schools

Background: Definitions of social accountability describe the obligation of medical schools to direct education, research and service activities towards addressing the priority health concerns of the population they serve. While such statements give some direction as to how the goal might be reached, it does not identify what factors might facilitate or hinder its achievement. This study set out to identify and explore enablers and barriers influencing the incorporation of social accountability values into medical schools. Methods: Semi structured interviews of fourteen senior staff in Bar Ilan and Leeds medical schools were undertaken following a literature review. Participants were recruited by purposive sampling in order to identify factors perceived to play a part in the workings of each institution. Results: Academic prestige was seen as a key barrier that was dependent on research priorities and student selection. The role of champions was considered to be vital to tackle staff perceptions and facilitate progress. Including practical community experience for students was felt to be a relevant way in which the curriculum could be designed through engagement with local partners. Conclusions: Successful adoption of social accountability values requires addressing concerns around potential negative impacts on academic prestige and standards. Identifying and supporting credible social accountability champions to disseminate the values throughout research and education departments in medical and other faculties is also necessary, including mapping onto existing work streams and research agendas. Demonstrating the contribution the institution can make to local health improvement and regional development by a consideration of its economic footprint may also be valuable

Challenges and Opportunities in China’s Health Aid to Africa: Findings from Qualitative Interviews in Tanzania and Malawi

Background China has played an increasing role in development aid across Africa. Most recently, China has increased its external investments through the Belt and Road Initiative, China’s signature infrastructure and trade drive to link China to Asia and Africa. This is likely to result in continuing growth of China’s investment in health in sub Saharan Africa. While conflicting opinions have been raised regarding the motivation and value of these investments, few data have been solicited from those directly involved in China-Africa health aid. We conducted a qualitative study to collect information on perceptions and opinions regarding Chinese-supported health related activities in Africa through in-depth interviews among local African and Chinese participants in Malawi and Tanzania. Results Our findings reveal shared experiences and views related to challenges in communication; cultural perspectives and historical context; divergence between political and business agendas; organization of aid implementation; management and leadership; and sustainability. Participants were broadly supportive and highly valued Chinese health aid. However, they also shared common insights that relate to challenging coordination between China and recipient countries; impediments to communication between health teams; and limited understanding of priorities and expectations. Further, they share perspectives about the need for shaping the assistance based on needs assessments as well as the importance of rigorous reporting, and monitoring and evaluation systems. Summary Our findings suggest that China faces similar challenges to those experienced by other longstanding development aid and global health donors. As it continues to expand cooperation across Africa and other regions, it will be important for China to consider the issues identified through our study to help inform collaborative and effective global health assistance programs. The insights garnered from this research are not only relevant to China’s engagement in Africa but for other global health assistance donors as well