A Network Analysis of COVID-19 in the United States

Through methods in network theory and time-series analysis, we will analyze the spread of COVID-19 in the United States by determining trends in state-by-state daily cases through a network construction. Previous researchers have found frameworks for approximating the spread of the COVID-19 pandemic and identifying potential rises in cases by a network construction based on correlation of cases between regions [1]. Applying this network construction we determine how this network and its structure act as a predictor for overall COVID-19 cases in the United States by preforming a trend analysis on a variety of network statistics and US COVID-19 cases

Assessment of the perceptions and attitudes of construction aggregate mine operators and county regulatory officials regarding aggregate mining

Aggregate is the general name given to sand, gravel, limestone or other crushed stone materials. Crushed stone, in one form or another, is used in nearly every construction project. However, for a variety of reasons, the average citizen does not realize the importance or need for construction aggregate. As a result, individuals or groups who feel they may be negatively affected by the presence of an aggregate mine, frequently organize to oppose granting the permits required to operate them;A review of the literature suggests obtaining the permits required to mine and process construction aggregate is becoming a more difficult and protracted process;Understanding the attitudes one holds toward aggregate mining may explain the conflicts aggregate mine operators experience during the mine permitting process;This study was undertaken to examine perceptions and attitudes of aggregate mine operators and county regulatory officials regarding construction aggregate mine permitting. By examining the perceptions and attitudes of these groups, insight into problems encountered during the permitting process was gained;Data for this study were obtained from a questionnaire mailed to all licensed or registered aggregate mine operators and county regulatory zoning officials (or their designee) in Iowa and Kansas. Respondents, using a Likert-like scale, were asked to rate items pertaining to perceived problems, factors contributing to problems and processes to mitigate problems associated with aggregate mine permitting;Results of the study identify (1) attitudes of aggregate producers and county regulatory officials toward aggregate mining, (2) problems which may contribute to the difficulty aggregate miners experience when they attempt to obtain mining permits, (3) processes to mitigate problems encountered during permitting, and (4) support the use of educational sessions and processes as a means of resolving aggregate mine permitting problems. In addition, the study provides guidance to those involved in the aggregate mining industry and a frame of reference for further research

The volcanic geology of the southern wall of the Valle Del Bove, Mount Etna, Sicily

A thesis submitted in partial fulfillment of the requirements for the Degree of Doctor of Philosophy of the C.N.A.A.The Valle del Bove is a horse-shoe shaped depression, 8km long and 5km wide, cut into the eastern flanks of Mount Etna, Sicily. In the southern cliff walls there are exposed the lavas and pyroclastics erupted by six ancient centres of activity which existed in the vicinity of the site now occupied by the Valle del Bove. The majority of these volcanics originated at a centre, Trifoglietto II, which occupied a position on the site of the southern Valle del Bove, and which was still erupting lavas at 25,000 ys BP. A reconstruction of the topography which previously existed within the Valle del Bove, is accomplished by extrapolating preserved contours on the northern and southern walls of the depression. Reconstruction of the Trifoglietto II centre shows that its summit was probably between 2500m and 2600m above present sea-level, and that it consisted of a cone constructed predominantly from pyroclastic materials, overlain on its southern and eastern flanks by lavas. A stratigraphy is constructed for the southern wall. The Trifoglietto II lavas rest unconformably upon the eroded remnants of an older centre, and are themselves overlain by the products of younger centres. All the lavas exposed in the southern wall are of alkalic affinity, and comprise a trachybasaltic suite ranging from hawaiite to benmoreite. Variation in the chemistry of most of the lavas can be explained by their differentiation at high levels in the crust, from a more basic magma of alkalibasalt/hawaiite composition. Chemical variation in the Trifoglietto II lavas, however, can best be explained as a result of generation by the partial melting of garnet-peridotite material at upper mantle depths and pressures. A study has been made of the numerous dykes exposed in the walls of the Valle del Bove., the alignments of which parallel trends which are important on Etna at the present time. It is proposed that the Valle del Bove was formed by phreatic or phreato-magmatic eruptions which destroyed the Trifoglietto II centre, some 15-17,000 ys BP, following magmatic extinction at the centre. The eruptions produced lahars which are evident to the east of the depression, and extensive air-fall ashes. Subsequent enlargement of the Valle del Bove was accomplished by fluvial erosion

Medial Prefrontal Cortical Activity Reflects Dynamic Re-Evaluation During Voluntary Persistence

Deciding how long to keep waiting for future rewards is a nontrivial problem, especially when the timing of rewards is uncertain. We carried out an experiment in which human decision makers waited for rewards in two environments in which reward-timing statistics favored either a greater or lesser degree of behavioral persistence. We found that decision makers adaptively calibrated their level of persistence for each environment. Functional neuroimaging revealed signals that evolved differently during physically identical delays in the two environments, consistent with a dynamic and context-sensitive reappraisal of subjective value. This effect was observed in a region of ventromedial prefrontal cortex that is sensitive to subjective value in other contexts, demonstrating continuity between valuation mechanisms involved in discrete choice and in temporally extended decisions analogous to foraging. Our findings support a model in which voluntary persistence emerges from dynamic cost/benefit evaluation rather than from a control process that overrides valuation mechanisms

Deciding to Curtail Persistence

Imagine that a few seconds ago you called a restaurant to book a reservation and were placed on hold. How soon do you expect to be helped? Are you having any difficulty waiting? Now imagine 5 minutes have gone by and you are still hearing hold music. Is it getting more difficult? Have your expectations changed? How much longer will you give them? Voluntary persistence toward delayed rewards has often been framed, in the psychological literature, as a self-control problem. This view presumes that it is generally beneficial to direct one\u27s behavior toward valuable prospects in the future, but that the fallible nature of self-control makes people sometimes succumb to immediate temptations instead. In laboratory studies, individuals who wait longer for delayed rewards have been deemed to possess greater self-control capacity. In real life, though, how long it is worth holding out for future rewards can be a more vexed question. Not all long-run rewards is complicated by the fact that future events are uncertain in both their substance and their timing. When it comes to choosing how long to wait for everything from city buses to customer service representatives, decision makers can as easily err by waiting too long--chasing sunk costs-- as by waiting too little. In this chapter we review research suggesting that the challenge of delaying gratification does not emerge merely from psychological limitations but instead reflects the genuine complexity of the environments in which real-world decisions take place

Decision Makers Calibrate Behavioral Persistence on the Basis of Time-Interval Experience

A central question in intertemporal decision making is why people reverse their own past choices. Someone who initially prefers a long-run outcome might fail to maintain that preference for long enough to see the outcome realized. Such behavior is usually understood as reflecting preference instability or self-control failure. However, if a decision maker is unsure exactly how long an awaited outcome will be delayed, a reversal can constitute the rational, utility-maximizing course of action. In the present behavioral experiments, we placed participants in timing environments where persistence toward delayed rewards was either productive or counterproductive. Our results show that human decision makers are responsive to statistical timing cues, modulating their level of persistence according to the distribution of delay durations they encounter. We conclude that temporal expectations act as a powerful and adaptive influence on people’s tendency to sustain patient decisions. Highlights ► Participants decided how long to wait for temporally uncertain rewards. ► The distribution of possible delays determines whether persistence is productive. ► Different conditions, matched for reward rate, required high or low persistence. ► With experience, decision makers appropriately adjusted their willingness to wait. ► Apparent failures of persistence can reflect adaptive temporal judgments

Control of Keratinocyte Division In Vitro

Aqueous extracts of newborn rat epidermis inhibit mitosis of cultivated keratinocytes obtained from guinea pigs and humans. The mitotic activity of cultivated human keratinocytes and fibroblasts obtained from the uninvolved skin of subjects with psoriasis is similar to the mitotic activity of these cells obtained from involved psoriatic skin. This observation is consistent with the model of repression of mitotic activity in normal skin and a derepression of mitotic activity in psoriatic epidermis. Extracts of liver also inhibit mitosis of guinea pig keratinocytes. Cultivated keratinocytes do not exhibit the same specificity of inhibition by epidermal extracts that has been reported for surviving fragments of mouse ear