Effects of Planning Horizon and Conception Rate on Profit-Maximizing Selection of Artificial Insemination Sires

Net present values of semen were calculated for alternative generations of descendants in the planning horizon, conception rate to first service, and selection policy for milk income and type score for retail semen prices and real interest 3%. Data were active Holstein and Jersey artificial insemination sires whose semen was available for purchase after the January 1984 USDA Sire Summary. Objectives were to determine effects of length of planning horizon and conception rate on rankings of sires for profit.Two generations (daughter and granddaughter) for Holstein and one generation of descendants for Jersey sires were sufficiently long planning periods, because sires ranked nearly the same (rank correlation >.99) with longer horizons. Misspecification of conception rate (largest cost), planning horizon, or both reduced profitability of sire selection by .4 to 1.2 standard deviations of net present value. Because of modest semen prices of most profitable sires, the largest cost of inefficient sire selection by inaccurate specification of conception rate and planning horizon is the opportunity loss of future net income. Interaction of optimal sire selection with herd management is analogous to interaction of genotype by environment for profit.     

Evaluation of integrated software development environments: Challenges and results from three empirical studies

Evidence shows that integrated development environments (IDEs) are too often functionality-oriented and difficult to use, learn, and master. This article describes challenges in the design of usable IDEs and in the evaluation of the usability of such tools. It also presents the results of three different empirical studies of IDE usability. Different methods are sequentially applied across the empirical studies in order to identify increasingly specific kinds of usability problems that developers face in their use of IDEs. The results of these studies suggest several problems in IDE user interfaces with the representation of functionalities and artifacts, such as reusable program components. We conclude by making recommendations for the design of IDE user interfaces with better affordances, which may ameliorate some of most serious usability problems and help to create more human-centric software development environments.     

Usability inspection of digital libraries: a case study

This paper reports a case study about lessons learned and usability issues encountered in a usability inspection of a digital library system called the Networked Computer Science Technical Reference Library (NCSTRL). Using a co-discovery technique with a team of three expert usability inspectors (the authors), we performed a usability inspection driven by a broad set of anticipated user tasks. We found many good design features in NCSTRL, but the primary result of a usability inspection is a list of usability problems as candidates for fixing. The resulting problems are organized by usability problem type and by system functionality, with emphasis on the details of problems specific to digital library functions. The resulting usability problem list was used to illustrate a cost/importance analysis technique that trades off importance to fix against cost to fix. The problems are sorted by the ratio of importance to cost, producing a priority ranking for resolution.     

A faster divide-and-conquer algorithm for constructing delaunay triangulations

An easily implemented modification to the divide-and-conquer algorithm for computing the Delaunay triangulation ofn sites in the plane is presented. The change reduces its (n logn) expected running time toO(n log logn) for a large class of distributions that includes the uniform distribution in the unit square. Experimental evidence presented demonstrates that the modified algorithm performs very well forn2¹⁶, the range of the experiments. It is conjectured that the average number of edges it creates—a good measure of its efficiency—is no more than twice optimal forn less than seven trillion. The improvement is shown to extend to the computation of the Delaunay triangulation in theL _p metric for 1<p.This research was supported by National Science Foundation Grants DCR-8352081 and DCR-8416190.     

A faster divide-and-conquer algorithm for constructing delaunay triangulations

An easily implemented modification to the divide-and-conquer algorithm for computing the Delaunay triangulation ofn sites in the plane is presented. The change reduces its Θ(n logn) expected running time toO(n log logn) for a large class of distributions that includes the uniform distribution in the unit square. Experimental evidence presented demonstrates that the modified algorithm performs very well forn≤2¹⁶, the range of the experiments. It is conjectured that the average number of edges it creates—a good measure of its efficiency—is no more than twice optimal forn less than seven trillion. The improvement is shown to extend to the computation of the Delaunay triangulation in theL _p metric for 1<p≤∞.     

Google: Das weltweit erste „Information Utility“?

In only ten years, Google has achieved remarkable success from online search-based advertising. Its search engine is dominant, and its IT infrastructure is the most powerful computing system in the world running on over one million computers and serving more than one billion users globally. Google makes money by using its search engine to deliver online advertising alongside responses to user searches for information, goods, maps, directions, and a host of other services. Its capabilities make it likely to become the world’s first information utility – a concept similar to electric utilities that provide services to many corporations and individuals alike. Constant innovation is the key to Google’s success and offers lessons for other companies: hire talented people, have them work in small teams, and give them freedom to excel, but use a rigorous data-based approach to evaluating results and making course adjustments.     

Physical and functional interactions between the herpes simplex virus UL15 and UL28 DNA cleavage and packaging proteins

Herpes simplex virus (HSV) DNA is cleaved from concatemers and packaged into capsids in infected cell nuclei. This process requires seven viral proteins, including UL15 and UL28. UL15 expressed alone displays a nuclear localization, while UL28 remains cytoplasmic. Coexpression with UL15 enables UL28 to enter nuclei, suggesting an interaction between the two proteins. Additionally, UL28 copurified with UL15 from HSV-infected cells after ion-exchange and DNA affinity chromatography, and the complex sedimented as a 1:1 heterodimer upon sucrose gradient centrifugation. These findings are evidence of a physical interaction of UL15 and UL28 and a functional role for UL15 in directing UL28 to the nucleus.     

Suppression of tumorigenicity of rat liver epithelial tumor cell lines by a putative human 11p11.2-p12 liver tumor suppressor locus

We have previously identified and mapped a locus within human chromosome 11p11.2-p12 that suppresses the tumorigenic potential of a rat liver tumor cell line (termed GN6TF) which contains well defined chromosomal aberrations involving rat chromosomes 1, 4, 7, and 10. In the present study, we investigated the potential of this human 11p11.2-p12 liver tumor suppressor locus to suppress the tumorigenic potential of two other rat liver tumor cell lines (GN3TG and GP10TA) following microcell-mediated introduction of human chromosome 11. These tumor cell lines are aneuploid and contain chromosomal abnormalities that are similar to the GN6TF tumor line. The tumorigenic potential and other phenotypic characteristics of GN3TG-11neo and GP10TA-11neo microcell hybrid (MCH) cell lines were variable, and dependent upon the status of the introduced human chromosome 11. MCH cell lines that retained the region of 11p11. 2-p12 delineated by microsatellite markers D11S1385 and D11S903 exhibited suppression of tumorigenicity in vivo (decrease in tumorigenicity and/or elongation of latency), whereas, the tumorigenic potential of one MCH line that lacked markers in this region of human 11p11.2-p12, but retained flanking markers, was not changed from that of the parental tumor cell line. The chromosomal interval between microsatellite markers D11S1385 and D11S903 encompasses the previously localized minimal liver tumor suppressor region, suggesting that a common locus is responsible for tumor suppression among the rat liver tumor cell lines examined. The results of the present study have verified the presence of a liver tumor suppressor locus within human 11p11.2-p12, and have identified a substantial number of microsatellite markers that are closely linked to this tumor suppressor region. These chromosomal markers will facilitate positional cloning of candidate genes from this region, and may prove useful for determining the involvement of this locus in the pathogenesis of human liver cancer.     

TCR-independent pathways mediate the effects of antigen dose and altered peptide ligands on Th cell polarization

We examined the role of the peptide/MHC ligand in CD4+ T cell differentiation into Th1 or Th2 cells using a TCR alphabeta transgenic mouse specific for hemoglobin (Hb)(64-76)/I-Ek. We identified two altered peptide ligands of Hb(64-76) that retain strong agonist activity but, at a given dose, induce cytokine patterns distinct from the Hb(64-76) peptide. The ability of these peptides to produce distinct cytokine patterns at identical doses is not due to an intrinsic qualitative property. Each peptide can induce Th2 cytokines at low concentrations and Th1 cytokines at high concentrations and has a unique range of concentrations at which these distinct effects occur. The pattern of cytokines produced from limiting dilution of naive T cells demonstrated that the potential to develop an individual Th1 or Th2 cell is stochastic, independent of Ag dose. We propose that the basis for the observed effects on the Th1/Th2 balance shown by the altered peptide ligands and the amount of Ag dose involves the modification of soluble factors in bulk cultures that are the driving force that polarize the population to either a Th1 or Th2 phenotype.