Monitoring vegetation change and dynamics on U.S. Army training lands using satellite image time series analysis.

Given the significant land holdings of the U.S. Department of Defense, and the importance of those lands to support a variety of inherently damaging activities, application of sound natural resource conservation principles and proactive monitoring practices are necessary to manage military training lands in a sustainable manner. This study explores a method for, and the utility of, analyzing vegetation condition and trends as sustainability indicators for use by military commanders and land managers, at both the national and local levels, in identifying when and where vegetation-related environmental impacts might exist. The BFAST time series decomposition method was applied to a ten-year MODIS NDVI time series dataset for the Fort Riley military installation and Konza Prairie Biological Station (KPBS) in northeastern Kansas. Imagery selected for time-series analysis were 16-day MODIS NDVI (MOD13Q1 Collection 5) composites capable of characterizing vegetation change induced by human activities and climate variability. Three indicators related to gradual interannual or abrupt intraannual vegetation change for each pixel were calculated from the trend component resulting from the BFAST decomposition. Assessment of gradual interannual NDVI trends showed the majority of Fort Riley experienced browning between 2001 and 2010. This result is supported by validation using high spatial resolution imagery. The observed versus expected frequency of linear trends detected at Fort Riley and KPBS were significantly different and suggest a causal link between military training activities and/or land management practices. While both sites were similar with regards to overall disturbance frequency and the relative spatial extents of monotonic or interrupted trends, vegetation trajectories after disturbance were significantly different. This suggests that the type and magnitude of disturbances characteristic of each location result in distinct post-disturbance vegetation responses. Using a remotely-sensed vegetation index time series with BFAST and the indicators outlined here provides a consistent and relatively rapid assessment of military training lands with applicability outside of grassland biomes. Characterizing overall trends and disturbance responses of vegetation can promote sustainable use of military lands and assist land managers in targeting specific areas for various rehabilitation activities.

Vascular aphasia outcome after intravenous recombinant tissue plasminogen activator thrombolysis for ischemic stroke.

INTRODUCTION: No data about the specific outcome of aphasia after thrombolysis are available. Our aim was to describe the severity and type of aphasia after stroke thrombolysis. METHODS: This retrospective cohort study included consecutive aphasic patients hospitalized in the Stroke Unit of Dijon (University Hospital, France) between 2004 and 2009 for a first-ever ischemic stroke of the left middle cerebral artery. Aphasic syndromes and their severity (French version of the Boston Diagnostic Aphasia Examination) were evaluated during the first week and 3 months after stroke. RESULTS: In multivariate analyses, the severity of aphasia in the 37 thrombolysed patients was milder than in the 38 nonthrombolysed patients during the first week (adjusted OR = 10.13, 95% CI: 2.43-42.28, p = 0.002) and at 3 months (adjusted OR = 8.44, 95% CI: 2.76-25.80, p = 0.001). The frequency of mild aphasia (conduction or atypical) was not significantly higher in thrombolysed patients during the first week after stroke (adjusted OR = 5.80, 95% CI: 0.82-41.16, p = 0.079). CONCLUSION: The severity of aphasia during the first week and 3 months after stroke is milder in thrombolysed than in nonthrombolysed patients, perhaps because of a greater frequency of conduction and mild atypical aphasia.

Serum 25-hydroxyvitamin D predicts severity and prognosis in stroke patients.

BACKGROUND AND PURPOSE: We aimed to evaluate the association between 25-hydroxyvitamin D (25(OH)D) levels and both clinical severity at admission and outcome at discharge in stroke patients. METHODS: From February 2010 to December 2010, consecutive stroke patients admitted to the Department of Neurology of Dijon, France, were identified. Clinical information was collected. Serum concentration of 25(OH)D was measured at baseline. Stroke severity was assessed at admission using the NIHSS score. Functional impairment was evaluated at discharge using the modified Rankin scale (m-Rankin). Multivariate analyses were performed using logistic regression models. RESULTS: Of the 386 recorded patients, serum 25(OH)D levels were obtained in 382 (median value = 35.1 nM; IQR = 21-57.8). At admission, 208 patients had a NIHSS ≤5, with a higher mean 25(OH)D level than that observed in patients with moderate-to-high severity (45.9 vs. 38.6 nM, P < 0.001). In multivariate analyses, a 25(OH)D level in the lowest tertile (<25.7 nM) was a predictor of a NIHSS ≥6 (OR = 1.67; 95% CI = 1.05-2.68; P = 0.03). The mean 25(OH)D level was lower in patients with moderate-to-severe handicap at discharge (m-Rankin 3-6) than in patients with no or mild handicap (35.0 vs. 47.5 nM, P < 0.001). In multivariate analyses, the lowest tertile of 25(OH)D level (<25.7 nM) was associated with a higher risk of moderate-to-severe handicap (OR = 2.06; 95% CI = 1.06-3.94; P = 0.03). CONCLUSION: A low serum 25(OH)D level is a predictor of both severity at admission and poor early functional outcome in stroke patients. The underlying mechanisms of these associations remain to be investigated.

Prestroke antiplatelet therapy and early prognosis in stroke patients: the Dijon Stroke Registry.

BACKGROUND AND PURPOSE: Previous antiplatelet therapy (APT) in cardiovascular prevention is common in patients with first-ever stroke. We aimed to evaluate the prognostic value of APT on early outcome in stroke patients. METHODS: All first-ever strokes from 1985 to 2011 were identified from the population-based Stroke Registry of Dijon, France. Demographic features, risk factors, prestroke treatments and clinical information were recorded. Multivariate analyses were performed to evaluate the associations between pre-admission APT and both severe handicap at discharge, and mortality at 1 month and 1 year. RESULTS: Among the 4275 patients, 870 (20.4%) were previously treated with APT. Severe handicap at discharge was noted in 233 (26.8%) APT users and in 974 (28.7%) non-users. Prestroke APT use was associated with lower odds of severe handicap at discharge [adjusted odds ratio (OR): 0.79; 95% confidence interval (CI): 063-1.00; P = 0.046], non-significant better survival at 1 month [adjusted hazard ratio (HR): 0.87; 95% CI: 0.70-1.09; P = 0.222] and no effect on 1-year mortality (HR: 0.94; 95% CI 0.80-1.10; P = 0.429). In stratum-specific analyses, APT was associated with a lower risk of 1-month mortality in patients with cardioembolic ischaemic stroke (HR: 0.65; 95% CI: 0.43-0.98; P = 0.040). CONCLUSIONS: APT before stroke was associated with less severe handicap at discharge, with no significant protective effect for mortality at 1 month except in patients with cardioembolic stroke. No protective effect of APT was observed for mortality at 1 year. Further studies are needed to understand the mechanisms underlying the distinct effects of prior APT observed across the ischaemic stroke subtypes.

Stroke care organization overcomes the deleterious 'weekend effect' on 1-month stroke mortality: a population-based study.

BACKGROUND AND PURPOSE: Suffering a stroke during the weekend is associated with a poorer prognosis. The impact of implementing a dedicated stroke care network in Dijon, France, in 2003 on 30-day mortality in strokes/transient ischaemic attacks (TIA) occurring during weekends/bank holidays was evaluated. METHODS: All cases of stroke and TIA from 1985 to 2010 were identified from a population-based registry, using multiple overlapping sources of information. Demographics and clinical data were recorded. Cox regression models were used to evaluate associations between day of onset (weekdays versus weekends/bank holidays) and 30-day all-cause mortality. Data were stratified according to time periods [before (1985-2003) and after (2004-2010) implementation of the stroke network] and stroke subtypes (ischaemic stroke and intracerebral hemorrhage). RESULTS: Of the 5864 recorded patients, 1465 (25%) had their event during weekends/bank holidays. Patients with stroke/TIA during weekdays were comparable with those with stroke/TIA during weekends/bank holidays for baseline characteristics. Excess mortality was observed in patients with stroke/TIA during weekends/bank holidays during 1985-2003 (18.2% vs. 14.0%, P < 0.01) but not during 2004-2010 (8.4% vs. 8.3%, P = 0.74). Onset during weekends/bank holidays was associated with a higher risk of 30-day mortality during 1985-2003 (adjusted hazard ratio 1.26; 95% CI 1.06-1.51, P = 0.01), but not during 2004-2010 (adjusted hazard ratio 0.99; 95% CI 0.69-1.43, P = 0.97). CONCLUSION: The deleterious effect of weekends/bank holidays on early stroke mortality disappeared after the organization of a dedicated stroke care network in our community. Our findings provide strong support for the implementation of quality improvement initiatives in order to attenuate inequalities in the management of stroke patients.

One-year survival of demented stroke patients: data from the Dijon Stroke Registry, France (1985-2008).

BACKGROUND AND PURPOSE: Dementia is a frequent condition after stroke that may affect the prognosis of patients. Our aim was to determine whether post-stroke dementia was a predictor of 1-year case-fatality and to evaluate factors that could influence survival in demented stroke patients. METHODS: From 1985 to 2008, all first-ever strokes were recorded in the population-based stroke registry of Dijon, France (150, 000 inhabitants). Dementia was diagnosed during the first month following stroke, according to DSM-III and DSM-IV criteria. Survival was evaluated at 1 year and multivariate analyses were performed using Cox proportional hazards to identify independent predictive factors. RESULTS: We recorded 3948 first-ever strokes. Among these stroke patients, 3201 (81%) were testable, and of these, 653 (20.4%) had post-stroke dementia (337 women and 316 men). Demented patients had lower 1-year survival than patients without dementia (82.9% vs. 86.9%, P = 0.013). However, in multivariate analysis, dementia did not appear as an independent predictor of 1-year death. In demented stroke patients, age >80 years old, severe handicap at discharge, recurrent stroke within the first year and subarachnoid haemorrhage were associated with a higher risk of 1-year death, and the risk was lower in the study period 2003-2008. CONCLUSIONS: Dementia after stroke is not independently associated with an increased risk of death at 1 year. In recent years, 1-year case-fatality decreased in demented as well as in and non-demented patients suggesting that improvements in the management of stroke also benefited the most fragile patients.

[Rupture of intracranial dermoid cyst with disseminated lipid droplets]. / Dissémination sous-arachnoïdienne de gouttelettes lipidiques par rupture d'un kyste dermoïde intracérébral.

INTRODUCTION: Dermoid cysts are rare slow-growing benign tumors of the central nervous system generally diagnosed in the third to fifth decade. They are formed from inclusion of ectodermal elements during neural tube closure, and are mostly located along the cranial or spinal midline axis. They cause many non specific symptoms such as headache and seizures, and may spontaneously rupture spreading fatty droplets into the ventricles and subarachnoid spaces. Rupture of dermoid cysts causes sequelae which may vary from no symptoms to death. In general, subtotal surgical removal is required for ruptured dermoid cysts. CASE REPORTS: We report two cases of ruptured intracranial dermoid tumor with non-specific clinical presentations. The first rupture was asymptomatic and discovered on brain magnetic resonance imaging (MRI) performed for other purposes. The second case was identified on brain imaging performed because of daily headache. These dermoid cysts were not surgically treated. Surveillance was advised because of the spontaneously favourable outcome observed in both cases. CONCLUSION: Surgical removal is not the only treatment of ruptured dermoid cyst. Monitoring with brain MRI can be sufficient if the rupture has no severe clinical impact.

Image coding based on a fractal theory of iterated contractive image transformations.

The author proposes an independent and novel approach to image coding, based on a fractal theory of iterated transformations. The main characteristics of this approach are that (i) it relies on the assumption that image redundancy can be efficiently exploited through self-transformability on a block-wise basis, and (ii) it approximates an original image by a fractal image. The author refers to the approach as fractal block coding. The coding-decoding system is based on the construction, for an original image to encode, of a specific image transformation-a fractal code-which, when iterated on any initial image, produces a sequence of images that converges to a fractal approximation of the original. It is shown how to design such a system for the coding of monochrome digital images at rates in the range of 0.5-1.0 b/pixel. The fractal block coder has performance comparable to state-of-the-art vector quantizers.