Optimal risk in marketing resource allocation

Marketing resource allocation is increasingly based on the optimization of expected returns on investment. If the investment is implemented in a large number of repetitive and relatively independent simple decisions, it is an acceptable method, but risk must be considered otherwise. The Markowitz classical mean-deviation approach to value marketing activities is of limited use when the probability distributions of the returns are asymmetric (a common case in marketing). In this paper we consider a unifying treatment for optimal marketing resource allocation and valuation of marketing investments in risky markets where returns can be asymmetric, using coherent risk measures recently developed in finance. We propose a set of first order conditions for the solution, and present a numerical algorithm for the computation of the optimal plan. We use this approach to design optimal advertisement investments in sales response managementResource allocation, Coherent risk measures, Optimization, Sales response models

Constraining in situ cosmogenic nuclide paleo-production rates using sequential lava flows during a paleomagnetic field strength low

The geomagnetic field prevents a portion of incoming cosmic rays from reaching Earth’s atmosphere. During magnetic reversals and excursions, the field strength can decrease by up to 90% relative to the modern-day value. During such anomalies, cosmic ray bombardment to Earth’s atmosphere increases as evident from atmospheric ¹⁰Be anomalies recorded in sediment and ice cores. However, how the flux of cosmic rays to Earth’s surface varies during such geomagnetic anomalies is not well constrained. We measured fossil cosmogenic ³He in olivine from the tops of two pairs of ⁴⁰Ar/³⁹Ar age-dated Tahitian lava flows that erupted during the Matuyama-Brunhes reversal precursor event. We corrected these raw values for the diffusive loss of helium caused by heating from the overlying flow with a diffusion model using cooling rates and maximum temperature conditions based on field measurements of active lava flows from Kilauea, Hawaii. We assume the maximum temperature suggested by field measurements and thus present a limiting case for the highest diffusive loss corrections and thus the highest paleo-production rates. Based on paleomagnetic field strength reconstructions and scaling factor models, the upper limits of the corrected in situ 3He paleo-production rates (100 ± 23, 144 ± 35 atoms g⁻¹ a⁻¹) are in agreement with those expected during the period of a geomagnetic field strength low when these flow tops were exposed. However, the more plausible contact temperatures (<700°C maximum temperature in diffusion model) are associated with diffusion corrected paleo-production rates lower than those predicted by scalar models. This potential underestimation is likely a function of changes in local non-dipole field components, atmospheric density and/or an overestimation of the dipole field strength reduction during the M-B precursor event

Application of Cosmogenic Nuclides and Argon Geochronology to Paleoclimate, Paleomagnetism, and Paleohydrology

This dissertation uses argon geochronology and cosmogenic nuclide surface exposure dating methods to address three research questions. The first question concerns a geomagnetic instability recorded in lava flows on the island of Floreana in the Galapagos Archipelago. Changes in the Earth’s magnetic field (intensity and orientation) occur frequently throughout geologic time for reasons not yet fully understood. Accurately dating these changes is important because these events provide critical stratigraphic markers in many natural archives, and constraints on the timing of geomagnetic change help better our understanding of the geodynamo. The lava flow on Floreana records an 86% reduction in field strength and intermediate virtual geomagnetic pole (VGP) orientations. Our age determination of 925.7 ± 4.6 ka (2σ; n = 6; MSWD = 1.23) indicates that this flow and the flows associated with it that record nearly identical VGP’s, record the Santa Rosa Excursion. We confirm that this site records the second reported terrestrial evidence of this geomagnetic excursion. Our age is in agreement with sediment records, which indicate this event spanned 3 kyrs. The Santa Rosa Excursion can now be characterized as a global short-lived geomagnetic anomaly associated with an 86% reduction in field strength in equatorial regions (as compared to modern day field strength). Similarities between the Santa Rosa and Laschamp excursions illustrate that such events can occur when the geomagnetic field is either in its reversed or normal polarity state. The second research question addresses the timing of the most recent polarity transition of Earth's magnetic field. The Matuyama-Brunhes (M-B) polarity transition is the most well-studied of all polarity transitions however it's timing remains in debate. A ~10 kyrs mismatch between volcanic and sedimentary archives that record the reversal have been reported. Important geodynamic insights can be gained by examining the structure of a reversing field through time, and the reliability of such studies requires accurate and precise timing of geomagnetic change. We use argon geochronology to date 13 Tahitian lava flows known to record the M-B reversal. A reconciliation between our new ages and those from previous literature from sedimentary and volcanic archives resolves this apparent temporal mismatch and suggests ~35 kyrs of instability and millennial to centennial timescale changes in VGP orientations prior to the Brunhes chron. This new illustration of the structure of a reversing field through time offers new insights into the short precursor history of a reversing field and the rapid -- if not erratic -- changing field dynamics during periods of low-dipole intensity. The final research question involves establishing the timing of intermittent catastrophic drainage of Glacial Lake Missoula in Montana and the associated large-scale flooding across the Columbia Basin and down the Columbia River to the Pacific Ocean during the last ice age. During the period from ~22,000 to ~13,000 years ago, there were perhaps 100 such flooding events that each lasted perhaps several weeks, with the amount of water in each flood being equivalent to ~20 times all of the world’s river flow combined. Surface exposure ages of boulders deposited by such floods at key geomorphic features can be used to determine flood routing, timing, and magnitude. This data may also suggest a source region of floods through time and help constrain the timing of Okanogan Lobe retreat. Eleven new site ages for flood related geomorphic features reveal the interplay between the Cordilleran Ice Sheet and the megafloods. We show that a large megaflood occurred at ~17.2 ka and traveled through an open northern Columbia River throughway before the advance of the Okanogan Lobe and impoundment of Glacial Lake Columbia. Okanogan Lobe retreat occurred between 14.0 to 14.8 ka and floods that occurred after Okanogan retreat were not as large as those before blockage of the northern Columbia. The relatively late retreat of the Okanogan Lobe as compared to the Puget Lobe may reflect independent controls on ice-sheet behavior. Radiocarbon ages indicating the minimum age of human occupation of the Pacific Northwest of the United States in combination with our most recent site ages suggest humans may have witnessed some of the youngest megafloods, which dramatic character likely influenced their oral traditions

Dating Clinopyroxene Phenocrysts in Submarine Basalts Using ^(40)Ar/^(39)Ar Geochronology

Dating submarine basalts using ^(40)Ar/^(39)Ar geochronology is often hindered by a lack of potassium‐bearing phenocrystic phases and severe alteration in the groundmass. Clinopyroxene is a common phenocrystic phase in seafloor basalts and is highly resistive to low‐temperature alteration. Here we show that clinopyroxene phenocrysts separated from marine basalts are a viable phase for ^(40)Ar/^(39)Ar incremental heating age determinations. We provide results from a pilot study comprising 16 age experiments from nine clinopyroxene separates, five of which from samples with dated coeval phases. The clinopyroxene ages range from 11.5 to 112 Ma with relatively high uncertainties (ranging from 0.8% to 7.1%; median of 1.9%) compared to more traditional phases. The clinopyroxene age plateaus form at low to moderate temperature steps and are characterized by relatively elevated K/Ca of 0.002–0.4, suggesting that other K‐bearing phases hosted within the clinopyroxene are likely degassing to yield the ^(40)Ar/^(39)Ar age information. There are three possible origins for the K and corresponding ^(40)Ar* including films of trapped melt/nanomineral inclusions along grain defects, secondary melt inclusion bands, or variations in degassing behaviors between lower and higher crystalline Ca pyroxene phases. Regardless of the source of the K, the age determinations are successful with 75% of the experiments producing long plateaus (>60% ^(39)Ar released) with mean square of the weighted deviations ranging from 0.6 to 1.5 and probability of fit values >0.05. We conclude that clinopyroxene dating by the ^(40)Ar/^(39)Ar method has the potential to provide a wealth of information for previously undated, altered seafloor lithologies and continental equivalents

International course on water and water management in the Philippines: 4 January - 31 January 2017

Since 2011, the Faculty of Social Sciences (FSW) and the Institute of Environmental Sciences (CML) of Leiden University, in cooperation with Isabela State University and the Mabuwaya Foundation in the Philippines organize an annual month–long international, interdisciplinary course on sustainable development, water issues and water management in the Cagayan River basin in Northeast Luzon in the Philippines. Thirty students participate in this course, 15 through Leiden University and 15 through Isabela State University. The students are enrolled in different studies, encompassing social, natural and applied sciences. The annual report contains background information, all student reports and the online blog that the students maintained during the course.Environmental BiologyGlobal Challenges (FSW

International course on water and water management in the Philippines: 6 January - 1 February 2019

Since 2011, the Faculty of Social Sciences (FSW) and the Institute of Environmental Sciences (CML) of Leiden University, in cooperation with Isabela State University and the Mabuwaya Foundation in the Philippines organize an annual month–long international, interdisciplinary course on sustainable development, water issues and water management in the Cagayan River basin in Northeast Luzon in the Philippines. Thirty students participate in this course, 15 through Leiden University and 15 through Isabela State University. The students are enrolled in different studies, encompassing social, natural and applied sciences. The annual report contains background information, all student reports and the online blog that the students maintained during the course.Global Challenges (FSW)Environmental BiologyConservation Biolog

International course on water and water management in the Philippines 2013

Since 2011, the Faculty of Social Sciences (FSW) and the Institute of Environmental Sciences (CML) of Leiden University, in cooperation with Isabela State University and the Mabuwaya Foundation in the Philippines organize an annual month–long international, interdisciplinary field course on sustainable development, water issues and water management in the Cagayan River basin and Sierra Madre Mountains in Northeast Luzon in the Philippines. Thirty students usually participate in this course, 15 through Leiden University and 15 through Isabela State University. The students are enrolled in different studies, encompassing social, natural and applied sciences. The annual report contains background information about that year’s course, all student reports and the online blog that the students maintained during the course.Environmental BiologyConservation Biolog

International Course on Water and Water Management in the Philippines 2015

Since 2011, the Faculty of Social Sciences (FSW) and the Institute of Environmental Sciences (CML) of Leiden University, in cooperation with Isabela State University and the Mabuwaya Foundation in the Philippines organize an annual month–long international, interdisciplinary field course on sustainable development, water issues and water management in the Cagayan River basin and Sierra Madre Mountains in Northeast Luzon in the Philippines. Thirty students usually participate in this course, 15 through Leiden University and 15 through Isabela State University. The students are enrolled in different studies, encompassing social, natural and applied sciences. The annual report contains background information about that year’s course, all student reports and the online blog that the students maintained during the course.Environmental BiologyConservation Biolog

Establishing freshwater protected areas to protect biodiversity and improve food security in the Philippines

This paper describes the efforts to establish a network of community-conserved areas in the municipality of San Mariano on Luzon, with the dual aim to protect the Philippine crocodile and to improve inland fisheries. The necessary steps to establish a community-conserved area are summarized, and their sustainability assessed. The importance of local leadership and democratic decision-making processes in the design of community-based conservation measures is highlighted, and it is argued that implicit cultural values, such as hospitality and respect, are often a more important motivation for rural communities to protect aquatic resources than explicit concerns about food security and livelihoods.Global Challenges (FSW)Environmental BiologyConservation Biolog