Subthalamic deep brain stimulation: clinical and neuropsychological outcomes in mild cognitive impaired parkinsonian patients

This observational study reports the long-term follow-up of 184 Parkinson's disease (PD) patients treated with subthalamic deep brain stimulation (STN-DBS), retrospectively analyzing the outcomes of subjects with pre-surgical mild cognitive impairment (MCI) compared to those of patients with normal cognition. Patients were divided into PD-MCI or normal cognition groups at baseline, and then compared after 1, 3, 5 and >5 years of follow-up. Subjects assessed by outpatient clinical follow-up evaluation, not performing a complete clinical and neuropsychological follow-up assessment, were separately considered and rated according to their functional autonomy in daily living activities. The MCI prevalence at baseline was 23 %, increasing to 34 % at 1 year and over 40 % after 3 years. Dementia progressively affected more than 30 % of subjects after a median time of 6 years in the PD-MCI group and 11 years in the normal cognition group (p: 0.028). The mortality risk was slightly higher in PD-MCI patients. Outpatient clinical evaluations showed a progressive increase of subjects completely dependent in the activities of daily living, which ranged from the 11 % at 3 years to 23 % at 5 years and 31 % at >5 years. MCI can be frequently observed in PD patients, possibly influencing the outcome of surgical therapy. Our findings confirm the sustained long-lasting efficacy of STN-DBS on motor functions in both PD-MCI and normal cognition subjects. PD-MCI patients showed a more precocious cognitive impairment, as expected by natural history studies, but no case of dementia was observed early after surgery.

Erratum to: Autonomic symptoms in idiopathic REM behavior disorder: a multicentre case–control study

Gene expression in mycorrhizal orchid protocorms suggests a friendly plant–fungus relationship

Orchids fully depend on symbiotic interactions with specific soil fungi for seed germination and early development. Germinated seeds give rise to a protocorm, a heterotrophic organ that acquires nutrients, including organic carbon, from the mycorrhizal partner. It has long been debated if this interaction is mutualistic or antagonistic. To investigate the molecular bases of the orchid response to mycorrhizal invasion, we developed a symbiotic in vitro system between Serapias vomeracea, a Mediterranean green meadow orchid, and the rhizoctonia-like fungus Tulasnella calospora. 454 pyrosequencing was used to generate an inventory of plant and fungal genes expressed in mycorrhizal protocorms, and plant genes could be reliably identified with a customized bioinformatic pipeline. A small panel of plant genes was selected and expression was assessed by real-time quantitative PCR in mycorrhizal and non-mycorrhizal protocorm tissues. Among these genes were some markers of mutualistic (e.g. nodulins) as well as antagonistic (e.g. pathogenesis-related and wound/stress-induced) genes. None of the pathogenesis or wound/stress-related genes were significantly up-regulated in mycorrhizal tissues, suggesting that fungal colonization does not trigger strong plant defence responses. In addition, the highest expression fold change in mycorrhizal tissues was found for a nodulin-like gene similar to the plastocyanin domain-containing ENOD55. Another nodulin-like gene significantly more expressed in the symbiotic tissues of mycorrhizal protocorms was similar to a sugar transporter of the SWEET family. Two genes coding for mannose-binding lectins were significantly up-regulated in the presence of the mycorrhizal fungus, but their role in the symbiosis is unclear.

Thermal tolerance affects mutualist attendance in an ant–plant protection mutualism

Mutualism is an often complex interaction among multiple species, each of which may respond differently to abiotic conditions. The effects of temperature on the formation, dissolution, and success of these and other species interactions remain poorly understood. We studied the thermal ecology of the mutualism between the cactus Ferocactus wislizeni and its ant defenders (Forelius pruinosus, Crematogaster opuntiae, Solenopsis aurea, and Solenopsis xyloni) in the Sonoran Desert, USA. The ants are attracted to extrafloral nectar produced by the plants and, in exchange, protect the plants from herbivores; there is a hierarchy of mutualist effectiveness based on aggression toward herbivores. We determined the relationship between temperature and ant activity on plants, the thermal tolerance of each ant species, and ant activity in relation to the thermal environment of plants. Temperature played a role in determining which species interact as mutualists. Three of the four ant species abandoned the plants during the hottest part of the day (up to 40 °C), returning when surface temperature began to decrease in the afternoon. The least effective ant mutualist, F. pruinosus, had a significantly higher critical thermal maximum than the other three species, was active across the entire range of plant surface temperatures observed (13.8-57.0 °C), and visited plants that reached the highest temperatures. F. pruinosus occupied some plants full-time and invaded plants occupied by more dominant species when those species were thermally excluded. Combining data on thermal tolerance and mutualist effectiveness provides a potentially powerful tool for predicting the effects of temperature on mutualisms and mutualistic species.

“I know it’s changed”: a mixed-methods study of the meaning of Global Perceived Effect in chronic neck pain patients

Global Perceived Effect (GPE) is a commonly used outcome measure for musculoskeletal conditions like neck pain; however, little is known regarding the factors patients take into account when determining their GPE. The overall objective of this work was to describe the thematic variables, which comprise the GPE from the patient's perspective.

Solutions of the Bethe-Salpeter Equation in Minkowski space: a comparative study

The Bethe-Salpeter Equation for a two-scalar, S-wave bound system,interacting through a massive scalar, is investigated within the ladderapproximation. By assuming a Nakanishi integral representation of theBethe-Salpeter amplitude, one can deduce new integral equations that can besolved and quantitatively studied, overcoming the analytic difficulties of theMinkowski space. Finally, it is shown that the Light-front distributions of the valence state,directly obtained from the Bethe-Salpeter amplitude, open an effective windowfor studying the two-body dynamics.

Spatial variability of maximum and minimum monthly temperature in Spain during 1981–2010 evaluated by correlation decay distance (CDD)

The spatial variability of monthly diurnal and nocturnal mean values of temperature in Spain has been analysed to evaluate the optimal threshold distance between neighbouring stations that make a meteorological network (in terms of stations’ density) well representative of the conterminous land of Spain. To this end, the correlation decay distance has been calculated using the highest quality monthly available temperature series (1981–2010) from AEMet (National Spanish Meteorological Agency). In the conterminous land of Spain, the distance at which couples of stations have a common variance above the selected threshold (50 %, r Pearson ∼0.70) for both maximum and minimum temperature on average does not exceed 400 km, with relevant spatial and temporal differences, and in extended areas of Spain, this value is lower than 200 km. The spatial variability for minimum temperature is higher than for maximum, except in cold months when the reverse is true. Spatially, highest values are located in both diurnal and nocturnal temperatures to the southeastern coastland and lower spatial variability is found to the inland areas, and thus the spatial variability shows a clear coastland-to-inland gradient at annual and monthly scale. Monthly analyses show that the highest spatial variability in maximum and minimum temperatures occur in July and August, when radiation is maximum, and in lowland areas, (<200 m o.s.l.), which coincide with the mostly transformed landscapes, particularly by irrigation and urbanization. These results highlight local factors could play a major role on spatial variability of temperature. Being maximum and minimum temperature interstation correlation values highly variable in Spanish land, an average of threshold distance of about 200 km as a limit value for a well representative network should be recommended for climate analyses,.

Applying polygenic risk scores to postpartum depression

The etiology of major depressive disorder (MDD) is likely to be heterogeneous, but postpartum depression (PPD) is hypothesized to represent a more homogenous subset of MDD. We use genome-wide SNP data to explore this hypothesis. We assembled a total cohort of 1,420 self-report cases of PPD and 9,473 controls with genome-wide genotypes from Australia, The Netherlands, Sweden and the UK. We estimated the total variance attributable to genotyped variants. We used association results from the Psychiatric Genomics Consortia (PGC) of bipolar disorder (BPD) and MDD to create polygenic scores in PPD and related MDD data sets to estimate the genetic overlap between the disorders. We estimated that the percentage of variance on the liability scale explained by common genetic variants to be 0.22 with a standard error of 0.12, p = 0.02. The proportion of variance (R (2)) from a logistic regression of PPD case/control status in all four cohorts on a SNP profile score weighted by PGC-BPD association results was small (0.1 %) but significant (p = 0.004) indicating a genetic overlap between BPD and PPD. The results were highly significant in the Australian and Dutch cohorts (R (2) > 1.1 %, p < 0.008), where the majority of cases met criteria for MDD. The genetic overlap between BPD and MDD was not significant in larger Australian and Dutch MDD case/control cohorts after excluding PPD cases (R (2) = 0.06 %, p = 0.08), despite the larger MDD group affording more power. Our results suggest an empirical genetic evidence for a more important shared genetic etiology between BPD and PPD than between BPD and MDD.

Who and what links to the Internet Archive

The Internet Archive's (IA) Wayback Machine is the largest and oldest public Web archive and has become a significant repository of our recent history and cultural heritage. Despite its importance, there has been little research about how it is discovered and used. Based on Web access logs, we analyze what users are looking for, why they come to IA, where they come from, and how pages link to IA. We find that users request English pages the most, followed by the European languages. Most human users come to Web archives because they do not find the requested pages on the live Web. About 65 % of the requested archived pages no longer exist on the live Web. We find that more than 82 % of human sessions connect to the Wayback Machine via referrals from other Web sites, while only 15 % of robots have referrers. Most of the links (86 %) from Websites are to individual archived pages at specific points in time, and of those 83 % no longer exist on the live Web. Finally, we find that users who come from search engines browse more pages than users who come from external Web sites.

Profiling web archive coverage for top-level domain and content language

The Memento Aggregator currently polls every known public web archive when serving a request for an archived web page, even though some web archives focus on only specific domains and ignore the others. Similar to query routing in distributed search, we investigate the impact on aggregated Memento TimeMaps (lists of when and where a web page was archived) by only sending queries to archives likely to hold the archived page. We profile fifteen public web archives using data from a variety of sources (the web, archives' access logs, and fulltext queries to archives) and use these profiles as resource descriptor. These profiles are used in matching the URI-lookup requests to the most probable web archives. We define $$Recall_{TM}(n)$$ R e c a l l T M ( n ) as the percentage of a TimeMap that was returned using $$n$$ n web archives. We discover that only sending queries to the top three web archives (i.e., 80 % reduction in the number of queries) for any request reaches on average $$Recall_{TM}=0.96$$ R e c a l l T M = 0.96 . If we exclude the Internet Archive from the list, we can reach $$Recall_{TM}=0.647$$ R e c a l l T M = 0.647 on average using only the remaining top three web archives.