Neither dust nor black carbon causing apparent albedo decline in Greenland\u27s dry snow zone: Implications for MODIS C5 surface reflectance

Remote sensing observations suggest Greenland ice sheet (GrIS) albedo has declined since 2001, even in the dry snow zone. We seek to explain the apparent dry snow albedo decline. We analyze samples representing 2012–2014 snowfall across NW Greenland for black carbon and dust light-absorbing impurities (LAI) and model their impacts on snow albedo. Albedo reductions due to LAI are small, averaging 0.003, with episodic enhancements resulting in reductions of 0.01–0.02. No significant increase in black carbon or dust concentrations relative to recent decades is found. Enhanced deposition of LAI is not, therefore, causing significant dry snow albedo reduction or driving melt events. Analysis of Collection 5 Moderate Resolution Imaging Spectroradiometer (MODIS) surface reflectance data indicates that the decline and spectral shift in dry snow albedo contains important contributions from uncorrected Terra sensor degradation. Though discrepancies are mostly below the stated accuracy of MODIS products, they will require revisiting some prior conclusions with C6 data

Similarity in depressive symptom profile in a population-based study of migrants in the Netherlands

Objective Depression is a clinical syndrome developed in Western Europe and North-America. The expression of symptoms and the impact of symptoms on functioning may therefore be expected to vary across cultures and languages. Our first aim was to study differences in depressive symptom profile between indigenous and non-Western immigrant populations in the Netherlands. We hypothesized that differences in expression of depressive symptoms would be more likely in the domains of mood and cognitions, and less likely in the domains of psychomotor and vegetative symptoms. Our second aim was to study ethnic differences in the association of depressive symptoms and general functioning. Method In a random community sample stratified for ethnicity in Amsterdam, the Netherlands, depressive symptoms were assessed by bilingual interviewers using the Composite International Diagnostic Interview (CIDI 2.1) and the Symptom Checklist-90-Revised (SCL-90-R). Impairments in functioning were measured by the World Health Organization Disability Assessment Schedule II (WHODAS II). Results were obtained from 812 subjects: N = 321 native Dutch, N = 213 Turkish-Dutch, N = 191 Moroccan-Dutch, N = 87 Surinamese-Dutch. Differences in depressive symptom expression were tested by differential item functioning. Results The prevalence of DSM-IV depressive disorder and the overall level of depressive symptoms were higher in the Turkish and Moroccan immigrant groups compared to native Dutch subjects. Ethnic differences in item functioning of depressive symptoms were rare, and equally unlikely in all four symptom domains. Depression was equally associated with functional impairment across ethnic groups. Conclusion Although depressive symptoms were more common among migrants than in the indigenous population, both the depressive symptom profile and the associated functional impairments were comparable. These findings may help diminishing concerns about the validity of using existing diagnostic procedures among ethnic minority groups

Loss of cholinergic innervation differentially affects eNOS-mediated blood flow, drainage of Aβ and cerebral amyloid angiopathy in the cortex and hippocampus of adult mice

Vascular dysregulation and cholinergic basal forebrain degeneration are both early pathological events in the development of Alzheimer’s disease (AD). Acetylcholine contributes to localised arterial dilatation and increased cerebral blood flow (CBF) during neurovascular coupling via activation of endothelial nitric oxide synthase (eNOS). Decreased vascular reactivity is suggested to contribute to impaired clearance of β-amyloid (Aβ) along intramural periarterial drainage (IPAD) pathways of the brain, leading to the development of cerebral amyloid angiopathy (CAA). However, the possible relationship between loss of cholinergic innervation, impaired vasoreactivity and reduced clearance of Aβ from the brain has not been previously investigated. In the present study, intracerebroventricular administration of mu-saporin resulted in significant death of cholinergic neurons and fibres in the medial septum, cortex and hippocampus of C57BL/6 mice. Arterial spin labelling MRI revealed a loss of CBF response to stimulation of eNOS by the Rho-kinase inhibitor fasudil hydrochloride in the cortex of denervated mice. By contrast, the hippocampus remained responsive to drug treatment, in association with altered eNOS expression. Fasudil hydrochloride significantly increased IPAD in the hippocampus of both control and saporin-treated mice, while increased clearance from the cortex was only observed in control animals. Administration of mu-saporin in the TetOAPPSweInd mouse model of AD was associated with a significant and selective increase in Aβ40-positive CAA. These findings support the importance of the interrelationship between cholinergic innervation and vascular function in the aetiology and/or progression of CAA and suggest that combined eNOS/cholinergic therapies may improve the efficiency of Aβ removal from the brain and reduce its deposition as CAA

Operations management

xiv, 426 hlm.;25 c

Introducing operations management

ix, 506 p. : ill. ; 26 c

Quantitative Business Modeling

454.;xxiv.;26 c

Project Management a Managerial Approach

Designed for project management courses for business students, Project Management: A Managerial Approach, 9th Edition guides students through all facets of the steps needed to successfully manage a project. The authors managerial perspective addresses the basic nature of managing all types of projects as well as the specific techniques and insights required for selecting, initiating, executing, and evaluating those projects