Seasonal variation of admission severity and outcomes in ischemic stroke – a consecutive hospital-based stroke registry

Different morbidities and mortalities of ischemic stroke may occur among seasons. For detecting the seasonal variations of severity after stroke onset and prognosis, we employed a retrospective analysis on a prospective regional hospital-based stroke registry and included a total of 1039 consecutive patients with onset date from January 2014 to December 2015. Patients were divided into four groups according to the onset seasons. Baseline characteristics, stroke subtypes, admission National Institute of Health Stroke Scale (NIHSS) score and modified Rankin Scale (mRS) score in 90 d were recorded and compared. Ordinal logistic regression was used to evaluate the association of seasons and severity or outcomes. Higher proportion of cardiac embolisms appeared in spring and winter (p < 0.001). The median admission NIHSS score was 5 in spring, 3 in summer, 4 in fall and 4 in winter (p = 0.036). After 90 d from onset, 40.5% of patients in spring suffered poor outcome (mRS 3–6), while 24.6% in summer, 33.9% in fall and 40.1% in winter (p < 0.001). After adjusted for age, sex, stroke subtypes and other covariates, patients in spring and winter had 1.76 times (95%CI 1.14–2.70, p = 0.010) and 1.53 times (95%CI 1.08–2.18, p = 0.017) the risk of suffering higher severity category than patients in summer, respectively. Compared with summer group, risk of worse outcomes at 90 d increased to 2.30 times in spring (95%CI 1.53–3.45, p < 0.001), 1.57 times in fall (95%CI 1.14–2.16, p = 0.006) and 2.09 times in winter (95%CI 1.50–2.91, p < 0.001), respectively. In conclusion, onset seasons were associated with severity and outcomes in ischemic stroke, and patients admitted in spring and winter had more severity and worse outcomes than patients in summer.     

Influence of human disturbance on patterns of leaf herbivory at Gazi Bay mangrove forest,Kenya

Mangrove herbivores cause leaf serration, perforation and galls prior to leaf abscission. This study compared damage by herbivores on leaves of four mangrove species at sites under different levels of human physical disturbance, and provides further evidence of the indirect effects of man on these valuable habitats. From 2001 to 2003 leaves collected fortnightly using litter traps were examined for evidence of herbivore damage, e.g. holes, margin damage, and a mix of both holes and margin damage on the leaf, and compared using ANOVA. Of 10 600 leaves examined, 3 604 had evidence of herbivore attack, with margin damage being most prevalent (60%). On Rhizophora mucronata, holes and mixed damage occurred on over 30% of damaged leaves, while margin damage was common to all other species examined. Leaf attack intensity was 14% lower at undisturbed sites, with margin damage being most common. Comparison between corresponding mangrove forest sites in Kenya showed significant increase in margin damage and concurrent decline in holes and mixed damage at disturbed sites. Variation in leaf damage occurrence was attributed to changes in forest structural and biological complexity owing to selective harvesting of flora and fauna that influenced the competitive ability and prevalence of aerial herbivorous guild.     

The effect of prey movement on attack behavior and patch residence decision rules of wolf spiders (Araneae: Lycosidae)

We used a video imaging technique to test the effects of prey movement on attack behavior and foraging patch residence time decision rules of wolf spiders. TwelveSchizocosa ocreata (Hentz) (Lycosidae) were tested in an artificial foraging patch stimulus chamber consisting of a microscreen television displaying a computer digitized, animated image of a cricket. Four prey movement treatments were used: (1) a blank screen, (2) a stationary cricket control, (3) a cricket moving for 1 min, and (4) a cricket moving for 10 min. Spiders stayed significantly longer in treatments with higher cricket activity. Spiders also stayed longer when they attacked the stimulus than when they did not. The distribution of patch residence times of spiders indicates a decision rule based on a fixed probability of leaving.