Faster all-pairs shortest paths via circuit complexity

We present a new randomized method for computing the min-plus product (a.k.a., tropical product) of two $n \times n$ matrices, yielding a faster algorithm for solving the all-pairs shortest path problem (APSP) in dense $n$-node directed graphs with arbitrary edge weights. On the real RAM, where additions and comparisons of reals are unit cost (but all other operations have typical logarithmic cost), the algorithm runs in time $$\frac{n^3}{2^{\Omega(\log n)^{1/2}}}$$ and is correct with high probability. On the word RAM, the algorithm runs in $n^3/2^{\Omega(\log n)^{1/2}} + n^{2+o(1)}\log M$ time for edge weights in $([0,M] \cap {\mathbb Z})\cup\{\infty\}$. Prior algorithms used either $n^3/(\log^c n)$ time for various $c \leq 2$, or $O(M^{\alpha}n^{\beta})$ time for various $\alpha > 0$ and $\beta > 2$. The new algorithm applies a tool from circuit complexity, namely the Razborov-Smolensky polynomials for approximately representing ${\sf AC}^0[p]$ circuits, to efficiently reduce a matrix product over the $(\min,+)$ algebra to a relatively small number of rectangular matrix products over ${\mathbb F}_2$, each of which are computable using a particularly efficient method due to Coppersmith. We also give a deterministic version of the algorithm running in $n^3/2^{\log^{\delta} n}$ time for some $\delta > 0$, which utilizes the Yao-Beigel-Tarui translation of ${\sf AC}^0[m]$ circuits into "nice" depth-two circuits.Comment: 24 pages. Updated version now has slightly faster running time. To appear in ACM Symposium on Theory of Computing (STOC), 201

Human Pose Estimation using Deep Consensus Voting

In this paper we consider the problem of human pose estimation from a single still image. We propose a novel approach where each location in the image votes for the position of each keypoint using a convolutional neural net. The voting scheme allows us to utilize information from the whole image, rather than rely on a sparse set of keypoint locations. Using dense, multi-target votes, not only produces good keypoint predictions, but also enables us to compute image-dependent joint keypoint probabilities by looking at consensus voting. This differs from most previous methods where joint probabilities are learned from relative keypoint locations and are independent of the image. We finally combine the keypoints votes and joint probabilities in order to identify the optimal pose configuration. We show our competitive performance on the MPII Human Pose and Leeds Sports Pose datasets

Periodically Varying Externally Imposed Environmental Effects on Population Dynamics

Effects of externally imposed periodic changes in the environment on population dynamics are studied with the help of a simple model. The environmental changes are represented by the temporal and spatial dependence of the competition terms in a standard equation of evolution. Possible applications of the analysis are on the one hand to bacteria in Petri dishes and on the other to rodents in the context of the spread of the Hantavirus epidemic. The analysis shows that spatio-temporal structures emerge, with interesting features which depend on the interplay of separately controllable aspects of the externally imposed environmental changes.Comment: 7 pages, 8 figures, include

Helping staff to implement psychosocial interventions in care homes: Augmenting existing practices and meeting needs for support

This is the author accepted manuscript. The final version is available from Wiley via the DOI in this recordObjective To contribute to an optimised training programme for care staff that supports the implementation of evidence-based psychosocial interventions in long-term care. Methods Qualitative study that involved focus group discussions with 119 care home staff within 16 care homes in the UK. Part of wider clinical trial aimed at developing and evaluating an effective and practical psychosocial intervention and implementation approach for people with dementia in long-term care. Inductive thematic analysis was used to identify themes and interpret the data. Results The findings highlighted that successful training and support interventions must acknowledge and respond to 'whole home' issues. Three overarching themes emerged as influential: the importance of contextual factors such as staff morale, interpersonal relationships within the home, and experience and perceived value of the proposed intervention. Conclusions Priority must be given to obtain the commitment of all staff, management and relatives to the training programme and ensure that expectations regarding interaction with residents, participation in activities and the reduction of medication are shared across the care home.National Institute for Health Research (NIHR

Improving quality of life for people with dementia in care homes: Making psychosocial interventions work

This is the author accepted manuscript. The final version is available from Cambridge University Press via the DOI in this recordPsychosocial interventions can improve behaviour and mood in people with dementia, but it is unclear how to maximise their effectiveness or acceptability in residential settings. Aims To understand what underlies the successful implementation of psychosocial interventions in care homes. Method Systematic review and meta-synthesis of qualitative research. Results The synthesis of 39 qualitative papers revealed that beneficial psychosocial interventions met the needs of people with dementia to connect with others, make a meaningful contribution and reminisce. Successful implementation rested on the active engagement of staff and family and the continuing provision of tailored interventions and support. This necessitated staff time, and raised issues around priorities and risk, but ultimately helped redefine staff attitudes towards residents and the caregiving role. Conclusions The findings from the meta-synthesis can help to inform the development and evaluation of psychosocial interventions in care homes and support their widespread implementation in clinical settings.National Institute for Health Research (NIHR

Monitoring wolf populations using howling points combined with sign survey transects

Wolves respond to simulated howling, especially during the mating and breeding seasons. Simulated howling points are, therefore, commonly used by many wolf researchers around the world to estimate pack numbers in a given area. A large amount of information is available on various pack breeding areas in Asturias, the only region in north-western Spain where the Iberian wolf (Canis lupus signatus, Cabrera 1907) is not classed as a game species. Wolf research began there in the early 1980s. We present the results of the latest study on population status, conducted between July and November, 2001. Using sampling transects to detect wolf scat and scratch marks and designated howling and observation points, twenty one (21) wolf packs were definitely located, with two others considered “likely”. Nineteen (19) packs were detected using howling points (n=314). The results of this study show that simulated howling points and sampling transects are reliable and inexpensive way of detecting wolf packs

The disconnect between evidence and practice: A systematic review of person-centred interventions and training manuals for care home staff working with people with dementia

This is the author accepted manuscript. The final version is available from the publisher via the DOI in this recordObjective The overall objective is to determine the availability of person-centred intervention and training manuals for dementia care staff with clinical trial evidence of efficacy. Design Interventions were identified using a search of electronic databases, augmented by mainstream search engines, reference lists, hand searching for resources and consultation with an expert panel. The specific search for published manuals was complemented by a search for randomised control trials focussing on training and activity-based interventions for people with dementia in care homes. Manuals were screened for eligibility and rated to assess their quality, relevance and feasibility. Results A meta-analysis of randomised control trials indicated that person-centred training interventions conferred significant benefit in improving agitation and reducing the use of antipsychotics. Each of the efficacious packages included a sustained period of joint working and supervision with a trained mental health professional in addition to an educational element. However, of the 170 manuals that were identified, 30 met the quality criteria and only four had been evaluated in clinical trials. Conclusions Despite the availability of a small number of evidence-based training manuals, there is a widespread use of person-centred intervention and training manuals that are not evidence-based. Clearer guidance is needed to ensure that commissioned training and interventions are based on robust evidence. Copyright © 2014 John Wiley & Sons, Ltd.National Institute for Health Research (NIHR

Logopenic and nonfluent variants of primary progressive aphasia are differentiated by acoustic measures of speech production

Differentiation of logopenic (lvPPA) and nonfluent/agrammatic (nfvPPA) variants of Primary Progressive Aphasia is important yet remains challenging since it hinges on expert based evaluation of speech and language production. In this study acoustic measures of speech in conjunction with voxel-based morphometry were used to determine the success of the measures as an adjunct to diagnosis and to explore the neural basis of apraxia of speech in nfvPPA. Forty-one patients (21 lvPPA, 20 nfvPPA) were recruited from a consecutive sample with suspected frontotemporal dementia. Patients were diagnosed using the current gold-standard of expert perceptual judgment, based on presence/absence of particular speech features during speaking tasks. Seventeen healthy age-matched adults served as controls. MRI scans were available for 11 control and 37 PPA cases; 23 of the PPA cases underwent amyloid ligand PET imaging. Measures, corresponding to perceptual features of apraxia of speech, were periods of silence during reading and relative vowel duration and intensity in polysyllable word repetition. Discriminant function analyses revealed that a measure of relative vowel duration differentiated nfvPPA cases from both control and lvPPA cases (r2 = 0.47) with 88% agreement with expert judgment of presence of apraxia of speech in nfvPPA cases. VBM analysis showed that relative vowel duration covaried with grey matter intensity in areas critical for speech motor planning and programming: precentral gyrus, supplementary motor area and inferior frontal gyrus bilaterally, only affected in the nfvPPA group. This bilateral involvement of frontal speech networks in nfvPPA potentially affects access to compensatory mechanisms involving right hemisphere homologues. Measures of silences during reading also discriminated the PPA and control groups, but did not increase predictive accuracy. Findings suggest that a measure of relative vowel duration from of a polysyllable word repetition task may be sufficient for detecting most cases of apraxia of speech and distinguishing between nfvPPA and lvPPA

Bannayan Ruvalcaba Riley Syndrome

A 63-year-old male with history of prostate cancer treated with radiation presented for a colonoscopy for small volume hematochezia. The colonoscopy revealed numerous polyps, which were found to be ganglioneuromas on histological examination. He was referred to medical genetics with suspicion for hamartomatous polyposis syndrome and was found to have a mutation in the PTEN gene. Based on this and suggestive clinical findings, he was diagnosed with Bannayan Ruvalcaba Riley syndrome