San Francisco State University

About: San Francisco State University is a education organization based out in San Francisco, California, United States. It is known for research contribution in the topics: Population & Planet. The organization has 5669 authors who have published 11433 publications receiving 408075 citations. The organization is also known as: San Francisco State & San Francisco State Normal School.

Manganese exposure: neuropsychological and neurological symptoms and effects in welders.

Abstract: Manganese exposure reportedly may have an adverse effect on CNS function and mood. Sixty-two welders with clinical histories of exposure to manganese were compared to 46 matched regional controls chosen at random from a telephone directory. The following tests were given: Wechsler Adult Intelligence Scale (WAIS-III), Wechsler Memory Scale (WMS-III), Boston Naming, WRAT-3, Cancellation H, Trail Making Tests A and B, Auditory Consonant Trigrams, Stroop, Rey-Osterreith, Animal Naming, Controlled Oral Word Association (COWAT), Test of Memory Malingering, Rey 15-item, Fingertapping, Grooved Pegboard, Dynamometer, Visual Attention Test, Lanthony d-15 Color Vision, Vistech Contrast Sensitivity, and Schirmer strips. The controls were administered a shorter battery of tests and the Rey-Osterreith, Animal Naming and some of the subtests of the WAIS-III, WMS-III were not administered. Mood tests, given to both groups, included the Symptom Checklist-40, Symptom Checklist-90-R, Profile of Mood Scale, Beck Depression Inventory II, and Beck Anxiety Inventory. Forty-seven welders and 42 controls were retained for statistical analysis after appropriate exclusions. Results showed a high rate of symptom prevalence and pronounced deficits in motor skills, visuomotor tracking speed and information processing, working memory, verbal skills (COWAT), delayed memory, and visuospatial skills. Neurological examinations compared to neuropsychological test results suggest that neuropsychologists obtain significantly more mood symptoms overall. Odds ratios indicate highly elevated risk for neuropsychological and neurological symptomatology of manganism. Mood disturbances including anxiety, depression, confusion, and impaired vision showed very high odds ratios. Neurological exams and neuropsychological tests exhibit complementarity and differences, though neuropsychological methods may be more sensitive in detecting early signs of manganism. The present study corroborates the findings of our previous study in another group of welders.

Pseudoframes for Subspaceswith Applications

Abstract: A notion of pseudoframes for subspaces (PFFS) is defined and characterized in a separable Hilbert space H. PFFS functions in a manner of a frame for a subspace X in H. Yet none of the pair of sequences {xn} and {x*n} is necessarily contained in X. This gives rise to attractive properties that center around the flexibility. A necessary and sufficient characterization of PFFSs is provided. Analytical formulae for the constructions of PFFSs in two directions are derived. Examples are considered. Some insight relationships of an PFFS for X and a frame of X are also observed thanks to a private communication with Casazza. Further applications of PFFSs are also discussed.

A model for fluvial bedrock incision by impacting suspended and bed load sediment

Abstract: [1] A mechanistic model is derived for the rate of fluvial erosion into bedrock by abrasion from uniform size particles that impact the bed during transport in both bed and suspended load. The erosion rate is equated to the product of the impact rate, the mass loss per particle impact, and a bed coverage term. Unlike previous models that consider only bed load, the impact rate is not assumed to tend to zero as the shear velocity approaches the threshold for suspension. Instead, a given sediment supply is distributed between the bed and suspended load by using formulas for the bed load layer height, bed load velocity, logarithmic fluid velocity profile, and Rouse sediment concentration profile. It is proposed that the impact rate scales linearly with the product of the near-bed sediment concentration and the impact velocity and that particles impact the bed because of gravitational settling and advection by turbulent eddies. Results suggest, unlike models that consider only bed load, that the erosion rate increases with increasing transport stage (for a given relative sediment supply), even for transport stages that exceed the onset of suspension. In addition, erosion can occur if the supply of sediment exceeds the bed load transport capacity because a portion of the sediment load is transported in suspension. These results have implications for predicting erosion rates and channel morphology, especially in rivers with fine sediment, steep channel-bed slopes, and large flood events.

Heat Waves, the New Normal: Summertime Temperature Extremes Will Impact Animals, Ecosystems, and Human Communities

Abstract: A consequence of climate change is the increased frequency and severity of extreme heat waves. This is occurring now as most of the warmest summers and most intense heat waves ever recorded have been during the past decade. In this review, I describe the ways in which animals and human populations are likely to respond to increased extreme heat, suggest how to study those responses, and reflect on the importance of those studies for countering the devastating impacts of climate change.