IRREVERSIBLE INVESTMENT DECISIONS IN PERENNIAL CROPS WITH YIELD AND PRICE UNCERTAINTY

Optimal entry and exit thresholds for Georgia commercial peach production are calculated when both price and yield follow a Brownian motion process. The thresholds are based on an irreversible sunk-cost investment model, where revenue from peach production is affected by the timing of when to enter production. Results indicate stability in Georgia peach production, with growers who are currently producing peaches remaining in production and potential peach growers delaying investment unless they have the ability of earning enhanced returns.Crop Production/Industries,

Participant Perceptions Of The Importance Of Situated Learning Design In The Delivery Of On-Line Training

Supervisor: Martha Cleveland - Innes, Ph.D.Situated learning has been recognized as an important approach to the design of programs for professional training and development programs. Knowledge is gained in the context of problem situations that are representative of the group’s professional practice. Participants gain knowledge and interact with program content that reflects the day-today reality of their experience. The intent of this study was to explore the perceptions of members of the addictions counseling profession in Canada, relative to the situated learning design features they felt were important elements in training programs delivered on-line. A case study approach was employed in this study, utilizing two questionnaires and a telephone interview to ascertain which situated learning elements they perceived as being important in their program delivery. There were nine situated learning elements that they considered. The feedback from the sample group suggested that on-line training programs should consider including the “provision of authentic context” and that facilitation should ensure “coaching and scaffolding at critical times”. These were deemed as being very important instructional design elements that should be present in their training programs. A number of other design elements were also indicated as being of importance, including: “promotion of articulation, provide access to expert performance, promote reflection, provision of multiple perspectives and the provision of authentic activities”. The situated learning elements least valued by the addiction counselors were: “provision of collaborative construction of knowledge and the provision of integrated assessment of knowledge”. The ongoing formative and summative evaluation of programs delivered on-line training might consider gaining participant feedback on the design elements that they feel are important to their situated learning

Bis[cis-bis­(diphenyl­phosphino)ethene-κ 2 P,P′]copper(I) tetra­fluoridoborate ethanol solvate

In the title compound [Cu(C26H22P2)2]BF4·C2H5OH, a disordered ethanol solvate molecule and the anions are located in well defined channels along the c axis. The four-coordinate Cu(P—P)2 core of the cation adopts approximately D 2 point group symmetry with the Cu—P bond lengths spanning a narrow range from 2.272 (1) to 2.285 (1) Å

The Intrinsic Absorber in QSO 2359-1241: Keck and HST Observations

We present detailed analyses of the absorption spectrum seen in QSO 2359-1241 (NVSS J235953-124148). Keck HIRES data reveal absorption from twenty transitions arising from: He I, Mg I, Mg II, Ca II, and Fe II. HST data show broad absorption lines (BALs) from Al III 1857, C IV 1549, Si IV 1397, and N V 1240. Absorption from excited Fe II states constrains the temperature of the absorber to 2000K < T < 10,000K and puts a lower limit of 10^5 cm^{-3} on the electron number density. Saturation diagnostics show that the real column densities of He I and Fe II can be determined, allowing to derive meaningful constraints on the ionization equilibrium and abundances in the flow. The ionization parameter is constrained by the iron, helium and magnesium data to -3.0 < log(U) < -2.5 and the observed column densities can be reproduced without assuming departure from solar abundances. From comparison of the He I and Fe II absorption features we infer that the outflow seen in QSO 2359-1241 is not shielded by a hydrogen ionization front and therefore that the existence of low-ionization species in the outflow (e.g., Mg II, Al III, Fe II) does not necessitate the existence of such a front. We find that the velocity width of the absorption systematically increases as a function of ionization and to a lesser extent with abundance. Complementary analyses of the radio and polarization properties of the object are discussed in a companion paper (Brotherton et al. 2000).Comment: 30 pages, 9 figures, in press with the Ap

The resurrection of group selection as a theory of human cooperation

Two books edited by members of the MacArthur Norms and Preferences Network (an interdisciplinary group, mainly anthropologists and economists) are reviewed here. These books in large part reflect a renewed interest in group selection that has occurred among these researchers: they promote the theory that human cooperative behavior evolved via selective processes which favored biological and/or cultural group-level adaptations as opposed to individual-level adaptations. In support of this theory, an impressive collection of cross-cultural data are presented which suggest that participants in experimental economic games often do not behave as self-interested income maximizers; this lack of self-interest is regarded as evidence of group selection. In this review, problems with these data and with the theory are discussed. On the data side, it is argued that even if a behavior seems individually-maladaptive in a game context, there is no reason to believe that it would have been that way in ancestral contexts, since the environments of experimental games do not at all resemble those in which ancestral humans would have interacted cooperatively. And on the theory side, it is argued that it is premature to invoke group selection in order to explain human cooperation, because more parsimonious individual-level theories have not yet been exhausted. In summary, these books represent ambitious interdisciplinary contributions on an important topic, and they include unique and useful data; however, they do not make a convincing case that the evolution of human cooperation required group selection

Facts from Faeces: Prey Remains in Wolf, Canis lupus, Faeces Revise Occurrence Records for Mammals of British Columbia's Coastal Archipelago

Archipelagos often harbour taxa that are endemic and vulnerable to disturbance. Conservation planning and research for these areas depend fundamentally on accurate and current taxonomic inventories. Although basic ecological information is in its infancy, the temperate rainforest islands of coastal British Columbia are undergoing rapid human-caused modification, particularly logging. We report herein new mammal records for these islands as determined by prey remains in the faeces of Wolves (Canis lupus), the area’s apex mammalian terrestrial predator. Of particular interest is our detection of Marten (Martes americana) on islands previously inventoried and island occupancy by Moose (Alces alces), which have apparently migrated recently to coastal British Columbia. Remains in faeces provided valuable new species occurrence information, but more extensive and focused inventories are required to generate predictions of island occupancy by mammals based on biotic and abiotic landscape features

Facts from Faeces: Prey Remains in Wolf, Canis lupus, Faeces Revise Occurrence Records for Mammals of British Columbia’s Coastal Archipelago

Archipelagos often harbour taxa that are endemic and vulnerable to disturbance. Conservation planning and research for these areas depend fundamentally on accurate and current taxonomic inventories. Although basic ecological information is in its infancy, the temperate rainforest islands of coastal British Columbia are undergoing rapid human-caused modification, particularly logging. We report herein new mammal records for these islands as determined by prey remains in the faeces of Wolves (Canis lupus), the area’s apex mammalian terrestrial predator. Of particular interest is our detection of Marten (Martes americana) on islands previously inventoried and island occupancy by Moose (Alces alces), which have apparently migrated recently to coastal British Columbia. Remains in faeces provided valuable new species occurrence information, but more extensive and focused inventories are required to generate predictions of island occupancy by mammals based on biotic and abiotic landscape features

The Use of Elastin-like Polypeptides as a Drug Carrier Material: A Compatibility Study

Stimuli responsive self-assembling nanoparticles of elastin-like polypeptides are promising platforms for targeted drug delivery and release. These particles spontaneously assemble from elastin-like polypeptide building blocks in solution. The nanoparticles stably self-assemble under specific temperature, salt, and pH conditions and can dissociate upon changing of these conditions. With appropriate design, the surface of the particles can be decorated with labels that cause them to accumulate in specific diseased tissues. In addition, the size of the particles is appropriate to minimize undesirable rapid clearance from the body. In this study, we are testing the ability of the elastin-like polypeptide core to store and release drugs and model drugs with differing chemical properties. Three chemotherapeutic compounds were loaded into the core of the nanoparticles and the release profile of the drug was determined under conditions that disrupt the particle. This release was compared to baseline release profile of the drug. This study is important in establishing the ability of ELP based nanoparticles to act as triggered drug release vehicles.https://engagedscholarship.csuohio.edu/u_poster_2014/1029/thumbnail.jp

Extended h-Index Parameterized Data Structures for Computing Dynamic Subgraph Statistics

We present techniques for maintaining subgraph frequencies in a dynamic graph, using data structures that are parameterized in terms of h, the h-index of the graph. Our methods extend previous results of Eppstein and Spiro for maintaining statistics for undirected subgraphs of size three to directed subgraphs and to subgraphs of size four. For the directed case, we provide a data structure to maintain counts for all 3-vertex induced subgraphs in O(h) amortized time per update. For the undirected case, we maintain the counts of size-four subgraphs in O(h^2) amortized time per update. These extensions enable a number of new applications in Bioinformatics and Social Networking research