3,604 research outputs found
Are California’s Charter Schools the New Separate-But-Equal “Schools of Excellence,” or Are They Worse Than Plessy?
The lack of quality education many charter schools offer disproportionately and adversely impacts communities of color. This article considered two models of charter school governance in use by California and Ohio. The first model posits that a fundamental tenet of charter schools is freedom from the burdensome bureaucracy traditional public schools bear. Based on the argument that deregulation enables charter schools to employ more innovative instructional and management practices, it assumes higher achievement scores would follow. The second model proposes to address educational inequality by increasing accountability on charter school authorizers by increasing regulatory practices. These models example the variety of governance models extant. In addition, arguments supporting each model are presented. The authors conclude with a discussion that supports the position that while autonomy is essential to maintaining the original objectives of charter schools, states must hold authorizers accountable for student achievement
Cerebral amyloid angiopathy in the aetiology and immunotherapy of Alzheimer disease
Amyloid is deposited in the walls of arteries and capillaries as cerebral amyloid angiopathy (CAA) in the brains of older individuals and of those with Alzheimer disease (AD). CAA in AD reflects an age-related failure of elimination of amyloid-beta (Aβ) from the brain along perivascular lymphatic drainage pathways. In the absence of conventional lymphatic vessel in the brain, interstitial fluid and solutes drain from the brain to cervical lymph nodes along narrow basement membranes in the walls of capillaries and arteries, a pathway that is largely separate from the cerebrospinal fluid. In this review we focus on the pathology and pathogenesis of CAA, its role in the aetiology of AD and its impact on immunotherapy for AD. The motive force for lymphatic drainage of the brain appears to be generated by arterial pulsations. Failure of elimination of Aβ along perivascular pathways coincides with a reduction in enzymic degradation of Aβ, reduced absorption of Aβ into the blood and age-related stiffening of artery walls that appears to reduce the motive force for lymphatic drainage. Reduced clearances of Aβ and CAA are associated with the accumulation of insoluble and soluble Aβs in the brain in AD and the probable loss of homeostasis of the neuronal environment due to retention of soluble metabolites within the brain. Tau metabolism may also be affected. Immunotherapy has been successful in removing insoluble plaques of Aβ from the brain in AD but with little effect on cognitive decline. One major problem is the increase in CAA in immunised patients that probably prevents the complete removal of Aβ from the brain. Increased knowledge of the physiology and structural and genetic aspects of the lymphatic drainage of Aβ from the brain will stimulate the development of therapeutic strategies for the prevention and treatment of AD
Probabilistic computer model of optimal runway turnoffs
Landing delays are currently a problem at major air carrier airports and many forecasters agree that airport congestion will get worse by the end of the century. It is anticipated that some types of delays can be reduced by an efficient optimal runway exist system allowing increased approach volumes necessary at congested airports. A computerized Probabilistic Runway Turnoff Model which locates exits and defines path geometry for a selected maximum occupancy time appropriate for each TERPS aircraft category is defined. The model includes an algorithm for lateral ride comfort limits
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