Cortical oscillatory dysrhythmias in visual snow syndrome: a magnetoencephalography study

Visual Snow refers to the persistent visual experience of static in the whole visual field of both eyes. It is often reported by patients with migraine and co-occurs with conditions like tinnitus and tremor. The underlying pathophysiology of the condition is poorly understood. Previously we hypothesised, that visual snow syndrome may be characterised by disruptions to rhythmical activity within the visual system. To test this, data from 18 patients diagnosed with visual snow syndrome, and 16 matched controls, were acquired using magnetoencephalography. Participants were presented with visual grating stimuli, known to elicit decreases in alpha-band (8-13Hz) power and increases in gamma-band power (40-70Hz). Data were mapped to source-space using a beamformer. Across both groups, decreased alpha power and increased gamma power localised to early visual cortex. Data from the primary visual cortex were compared between groups. No differences were found in either alpha or gamma peak frequency or the magnitude of alpha power, p>0.05. However, compared with controls, our visual snow syndrome cohort displayed significantly increased primary visual cortex gamma power, p=0.035. This new electromagnetic finding concurs with previous functional MRI and PET findings suggesting that in visual snow syndrome, the visual cortex is hyper-excitable. The coupling of alpha-phase to gamma amplitude within the primary visual cortex was also quantified. Compared with controls, the visual snow syndrome group had significantly reduced alpha-gamma phase-amplitude coupling, p<0.05, indicating a potential excitation-inhibition imbalance in visual snow syndrome, as well as a potential disruption to top-down “noise-cancellation” mechanisms. Overall, these results suggest that rhythmical brain activity in primary visual cortex is both hyperexcitable and disorganised in visual snow syndrome, consistent with this being a condition of thalamocortical dysrhythmia

A major subtropical fruit pest accumulates in crop fields and spills over to a wild host

This is the author accepted manuscript. The final version is available from the publisher via the DOI in this record.Wild plant species are often considered a source of crop pests in mixed landscapes but this view rarely considers pest spillover in the opposite direction (from crop fields to natural vegetation), or spatiotemporal variability in resources between crop and wild habitats. We investigate how infestation of mango crop (Mangifera indica, Anacardiaceae) and a related wild host (marula, Sclerocarya birrea, Anacardiaceae) by a major subtropical fruit crop pest (Ceratitis cosyra, Diptera: Tephritidae) varies with distance from the boundary between crop and natural vegetation. We determined how infestation of marula is associated with proximity to mango crops at field and landscape scales over two fruiting seasons on three farms in north-eastern South Africa. This is one of few studies to date to consider pest spillover from crop fields to natural vegetation and the only one performed in a biodiverse region with relatively little habitat transformation. Over three sampling periods, C. cosyra infestation of marula always decreased with distance from mango fields. At the landscape scale, marula alongside crop fields were 30 times more likely to be infested than in distant vegetation (1.3–6 km from mango), suggesting that spillover occurs from crop fields to natural vegetation. During late mango and marula fruiting, twice as many flies infested marula than mango. However, over the two months post-mango fruiting, up to 25 times more C. cosyra were trapped in mango fields than in bordering natural vegetation. Although pests spillover from crop fields into natural vegetation to use marula as an alternate host, biological control in the natural vegetation may eliminate this habitat as a pest reservoir outside the crop season. Other nearby crops may be more important than wild hosts for maintaining C. cosyra out of mango season. Landscape planning should consider proximity and arrangement of fields containing crops that host shared pests at different times of the year.This research was supported by the Mare Curie International Research Staff Exchange Scheme [Contract number 318929]; the National Research Foundation of South Africa [Grant number 90139]; and the South African Department of Science and Technology [Contract number 0054/2013]

On Directed Feedback Vertex Set parameterized by treewidth

We study the Directed Feedback Vertex Set problem parameterized by the treewidth of the input graph. We prove that unless the Exponential Time Hypothesis fails, the problem cannot be solved in time $2^{o(t\log t)}\cdot n^{\mathcal{O}(1)}$ on general directed graphs, where $t$ is the treewidth of the underlying undirected graph. This is matched by a dynamic programming algorithm with running time $2^{\mathcal{O}(t\log t)}\cdot n^{\mathcal{O}(1)}$. On the other hand, we show that if the input digraph is planar, then the running time can be improved to $2^{\mathcal{O}(t)}\cdot n^{\mathcal{O}(1)}$.Comment: 20

Idealness of k-wise intersecting families

A clutter is k-wise intersecting if every k members have a common element, yet no element belongs to all members. We conjecture that, for some integer k ≥ 4, every k-wise intersecting clutter is non-ideal. As evidence for our conjecture, we prove it for k = 4 for the class of binary clutters. Two key ingredients for our proof are Jaeger’s 8-flow theorem for graphs, and Seymour’s characterization of the binary matroids with the sums of circuits property. As further evidence for our conjecture, we also note that it follows from an unpublished conjecture of Seymour from 1975. We also discuss connections to the chromatic number of a clutter, projective geometries over the two-element field, uniform cycle covers in graphs, and quarter-integral packings of value two in ideal clutters

A multivariate analysis of the relationship between response and survival among patients with higher-risk myelodysplastic syndromes treated within azacitidine or conventional care regimens in the randomized AZA-001 trial.

The phase III AZA-001 study established that azacitidine significantly improves overall survival compared with conventional care regimens (hazard ratio 0.58 [95% confidence interval 0.43–0.77], P<0.001). This analysis was conducted to investigate the relationship between treatment response and overall survival. AZA-001 data were analyzed in a multivariate Cox regression analysis with response as a time-varying covariate. Response categories were “Overall Response” (defined as complete remission, partial remission, or any hematologic improvement) and “Stable Disease” (no complete or partial remission, hematologic improvement, or progression) or “Other” (e.g. disease progression). Achieving an Overall Response with azacitidine reduced risk of death by 95% compared with achieving an Overall Response with the conventional care regimens (hazard ratio 0.05 [95%CI: 0.01–0.43], P=0.006). Sensitivity analyses indicated that significantly improved overall survival remained manifest for patients with a hematologic improvement who had never achieved complete or partial remission (hazard ratio 0.19 [95%CI: 0.08–0.46], P<0.001). Stable Disease in both azacitidine-treated and conventional care-treated patients was also associated with a significantly reduced risk of death (hazard ratio 0.09, [95%CI: 0.06–0.15]; P<0.001). These results demonstrate azacitidine benefit on overall survival compared with conventional care regimens in patients with higher-risk myelodysplastic syndromes who achieve hematologic response but never attain complete or partial remission, in addition to the survival advantage conferred by achievement of complete or partial remission. This study was registered with clinicaltrials.gov (NCT00071799)

Indirect interactions between crops and natural vegetation through flower visitors: the importance of temporal as well as spatial spillover

This is the author accepted manuscript. The final version is available from Elsevier via the DOI in this recordAs the Anthropocene advances, understanding the complex web of interactions between species has become a central theme in the maintenance of biodiversity, ecosystem functions, and agricultural systems. Plant-flower visitor networks yield insights into how natural vegetation supports crop pollination. Although crops themselves also support pollinators, the importance of spillover of flower-visiting pollinators from natural vegetation into croplands is increasingly appreciated. Natural vegetation not only provides forage and nesting sites, but can also support crop flower visitors when the crop is not flowering. We evaluated indirect effects between mango (the dominant tropical fruit crop globally) and wild plant species in neighbouring vegetation, and the factors determining these indirect effects, by constructing flower visitor networks. We constructed these networks for transects that included mango fields and neighbouring natural vegetation in north-eastern South Africa. Surveys were conducted before, during and after mango flowering, to allow evaluation of the importance of pollinator support when the crop was not in flower. Network analysis showed that potential indirect effects of other plant species on mango increased with flower abundance of those species, although this increase was less marked for species growing in natural vegetation. The cumulative (total, i.e. indirect effects summed) effect of natural vegetation on mango flower visitation was greater both during mango flowering and when it was not flowering. This is likely because of the greater plant diversity in natural systems, and because the combination of these species provided flowers over a protracted period. These positive indirect effects among plants flowering over extended periods of time have to date rarely been considered in crop pollination studies. Given the rapid expansion of high-intensity, high-yield monoculture plantings, such effects warrant further investigation.Financial support was received from the National Research Foundation (NRF Grant number 90139), European Union Marie Curie IRSES project NETWORK (grant agreement: PIRSES-GA-2012-318929), Department of Science and Technology of South Africa (grant number DST/CON0054/2013)

The effects of continued azacitidine treatment cycles on response in higher risk patients with myelodysplastic syndromes: an update

The international, phase III, multi-centre AZA-001 trial demonstrated azacitidine (AZA) is the first treatment to significantly extend overall survival (OS) in higher risk myelodysplastic syndromes (MDS) patients (Fenaux (2007) Blood 110 817). The current treatment paradigm, which is based on a relationship between complete remission (CR) and survival, is increasingly being questioned (Cheson (2006) Blood 108 419). Results of AZA-001 show CR is sufficient but not necessary to prolong OS (List (2008) Clin Oncol 26 7006). Indeed, the AZA CR rate in AZA-001 was modest (17%), while partial remission (PR, 12%) and haematological improvement (HI, 49%) were also predictive of prolonged survival. This analysis was conducted to assess the median number of AZA treatment cycles associated with achievement of first response, as measured by IWG 2000-defined CR, PR or HI (major + minor). The number of treatment cycles from first response to best response was also measured

Azacitidine prolongs overall survival and reduces infections and hospitalizations in patients with WHO-defined acute myeloid leukaemia compared with conventional care regimens: an update

Azacitidine (AZA), as demonstrated in the phase III trial (AZA-001), is the first MDS treatment to significantly prolong overall survival (OS) in higher risk MDS pts ((2007) Blood 110 817). Approximately, one-third of the patients (pts) enrolled in AZA-001 were FAB RAEB-T (≥20–30% blasts) and now meet the WHO criteria for acute myeloid leukaemia (AML) ((1999) Blood 17 3835). Considering the poor prognosis (median survival <1 year) and the poor response to chemotherapy in these pts, this sub-group analysis evaluated the effects of AZA versus conventional care regimens (CCR) on OS and on response rates in pts with WHO AML

The costs, resource use, and cost-effectiveness of Clinical Nurse Specialist (CNSs) led interventions for patients with palliative care needs: a systematic review of international evidence

Background: Patients with palliative care (PC) needs do not access specialist palliative care services according to their necessities. Clinical Nurse Specialists (CNS) working across a variety of fields are playing an increasingly important role in the care of such patients, but there is limited knowledge of the extent to which their interventions are cost-effective. Objectives: To present results from a systematic review of the international evidence on the costs, resource use and cost effectiveness of CNS led interventions for patients palliative care needs, defined as seriously ill patients and those with advanced disease or frailty who are unlikely to be cured, recover, or stabilize. Design: Systematic review following PRISMA methodology. Data sources: Medline, Embase, Cinahl and Cochrane library up to 2015. Studies focusing on the outcomes of CNS interventions for patients with PC needs, and including at least one economic outcome, were considered. The quality of studies was assessed using tools from the Joanna-Briggs-Institute. Results: A total of 79 papers were included: 37 RCTs, 22 quasi-experimental studies, 7 service evaluations and other studies, and 13 economic analyses. The studies included a wide variety of interventions including clinical, support and education, as well as care coordination activities. The quality of the studies varied greatly. Conclusions: CNSs interventions may be effective in reducing specific resource use such as hospitalizations /re-hospitalizations/admissions, length of stay, and health care costs. There is mixed evidence regarding their cost-effectiveness. Future studies should ensure that clinical nurse specialists’ roles and activities are clearly described and evaluated