2,979 research outputs found

    Present net worth and internal rate of return: A note on equivalence in use

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    Present net worth and internal rate of return are frequently used for ranking investment alternatives. The relative merits and limitations of the two criteria are discussed at length in numerous journal articles and texts. For analysts wishing to present consistent project comparisons, the issue is not which criterion is superior, but when are they equivalent. In this article, conditions for equivalence in use are outlined under alternative assumptions. Although the conditions appear complex, they are not unduly restrictive

    In the Wake of the Storm: Environment, Disaster, and Race After Katrina

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    Studies evidence of environmental disparities by which poor and minority communities are disproportionately exposed to disasters, are less prepared, and have less access to relief agencies. Makes recommendations for preparedness and environmental justice

    Financial maturity concepts with application to three hardwood timber stands

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    Timber is “financially mature” when its rate of value increase falls below what the landowner can earn in alternative investments that are comparable in duration, risk, liquidity, and other factors. The basic concept of financial maturity is simple, but in application it involves several very important, basic questions and issues

    \u3ci\u3eSelachohemecus benzi\u3c/i\u3e n. sp. (Digenea: Sanguinicolidae) from the Blacktip Shark \u3ci\u3eCarcharhinus limbatus\u3c/i\u3e (Carcharhinidae) in the Northern Gulf of Mexico

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    Selachohemecus benzi Bullard & Overstreet n. sp. infects the heart and kidney of the blacktip shark Carcharhinus limbatus in the northern Gulf of Mexico off Florida and Mississippi, USA. Specimens of S. olsoni Short, 1954, the only congener and only other named blood fluke reported from a chondrichthyan in the Gulf of Mexico, were collected from the heart of the Atlantic sharpnose shark Rhizoprionodon terraenovae from two new localities, Apalachicola Bay, Florida, and Mississippi Sound, Mississippi, USA. The new species differs from S. olsoni by having a larger body (1.4–3.8 mm long), robust tegumental body spines numbering 51–63 along each lateral body margin, a testis extending from the posterior caeca to the ovary, and a medial ovary with lobes. We amend the diagnosis of Selachohemecus Short, 1954 to accommodate it and provide a diagnostic key for all named chondrichthyan blood flukes

    Monoclonal antibodies against human astrocytomas and their reactivity pattern

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    The establishment of hybridomas after fusion of X63-Ag8.653 mouse myeloma cells and splenocytes from mice hyperimmunized against human astrocytomas is presented. The animals were primed with 5 Ă— 106 chemically modified uncultured or cultured glioma cells. Six weeks after the last immunization step an intrasplenal booster injection was administrated and 3 days later the spleen cells were prepared for fusion experiments. According to the specificity analysis of the generated antibodies 7 hybridoma products (MUC 7-22, MUC 8-22, MUC 10-22, MUC 11-22, MUC 14-22, MUC 15-22 and MUC 2-63) react with gliomas, neuroblastomas and melanomas as well as with embryonic and fetal cells but do not recognize non-neurogenic tumors. The selected monoclonal antibodies (McAbs) of IgG1 and IgG2a isotypes are not extensively characterized but these antibodies have been demonstrated to be reactive with a panel of glioma cell lines with varying patterns of antigen distribution. Using the McAbs described above and a series of cryosections of glioma biopsies and paraffin sections of the same material as well as glioma cultures established from these, variable antigenic profiles among glioma cell populations could be demonstrated. From these results it is evident that there is not only a distinct degree of antigenic heterogeneity among and within brain tumors, but also that the pattern of antigenic expression can change continuously. Some of the glioma associated antigens recognized by the selected antibodies persist after fixation with methanol/acetone and Karnovsky's fixative and probably are oncoembryonic/oncofetal antigen(s). The data suggest that the use of McAbs recognizing tumor associated oncofetal antigens in immunohistochemistry facilitates objective typing of intracranial malignancies and precise analysis of fine needle brain/tumor biopsies in a sensitive and reproducible manner

    Reforestation of harvested Timberlands in Mississippi: Behavior and Attitudes of Non-Industrial, Private Forest Landowners

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    Southern forests play an increasingly important role in the timber economy as per capita demand for wood continues to expand. Moreover, harvest restrictions in the Pacific Northwest in the early 1990s shifted a large portion of United States demand for softwoods to the South. In Mississippi, most of the forestland is owned by non-industrial private forest (NIPF) landowners. Approximately 314,000 NIPF landowners control 66 percent of the state’s forestland base (Hartsell and London 1995). The sizable acreage of timberland held by NIPF landowners nationally and in-state underscores the importance of their role in the timber economy and weighs heavily in the supply of raw material to the state’s $11.4 billion forest products industry (Munn 1998)

    Collective private urban renewal in New Bedford's historic district

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    Thesis (M.C.P.)--Massachusetts Institute of Technology, Dept. of Urban Studies and Planning; and, (M. Arch.)--Massachusetts Institute of Technology, Dept. of Architecture, 1974.Includes bibliograpical references (leaves 72-74).This thesis examines the waterfront historic district in New Bedford, Massachusetts. It is, hopefully, the beginning of a process of collective private renewal that may lead the revival of the district as a vital element in the city's recovery. It describes the problems and some of the potential of an effort by an organized group of citizens to renew their community - an alternative to renewal by the government or by large developers. Two themes run throughout the thesis. The first is the city itself: how any attempt at planning for the district must acknowledge its relationship to the city. The second is the role the "professional" plays. This thesis is the work of a "location-oriented change-maker," a person whose first allegiance is to a location and its problems and secondly to a profession that might be involved in solutions to the problems. The thesis begins with a history of the district, which was the city in the days of whaling. It then discusses the problems that face the people of New Bedford today and the plans the city has for her future. The second part of the thesis is a description of the historic district and its people and concludes with a discussion of what it might become and how. Physical implications are included in the appendix.by John K. Bullard.M.Arch.M.C.P

    Preferential Accumulation of Antigen-specific Effector CD4 T Cells at an Antigen Injection Site Involves CD62E-dependent Migration but Not Local Proliferation

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    The migration of antigen-specific T cells to nonlymphoid tissues is thought to be important for the elimination of foreign antigens from the body. However, recent results showing the migration of activated T cells into many nonlymphoid tissues raised the possibility that antigen-specific T cells do not migrate preferentially to nonlymphoid tissues containing antigen. We addressed this question by tracking antigen-specific CD4 T cells in the whole body after a localized subcutaneous antigen injection. Antigen-specific CD4 T cells proliferated in the skin-draining lymph nodes and the cells that underwent the most cell divisions acquired the ability to bind to CD62P. As time passed, CD62P-binding antigen-specific CD4 T cells with interferon γ production potential accumulated preferentially at the site of antigen injection but only in recipients that expressed CD62E. Surprisingly, these T cells did not proliferate in the injection site despite showing evidence of more cell divisions than the T cells in the draining lymph nodes. The results suggest that the most divided effector CD4 T cells from the lymph nodes enter the site of antigen deposition via recognition of CD62E on blood vessels and are retained there in a nonproliferative state via recognition of peptide–major histocompatibility complex II molecules

    DNA Polymerase III Holoenzyme From Thermus Thermophilus Identification Expression Purification of Components and use to Reconstitute a Processive Replicase

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    DNA replication in bacteria is performed by a specialized multicomponent replicase, the DNA polymerase III holoenzyme, that consist of three essential components: a polymerase, the β sliding clamp processivity factor, and the DnaX complex clamp-loader. We report here the assembly of the minimal functional holoenzyme from Thermus thermophilus (Tth), an extreme thermophile. The minimal holoenzyme consists of α (pol III catalytic subunit), β (sliding clamp processivity factor), and the essential DnaX (τ/γ), δ and δ′ components of the DnaX complex. We show with purified recombinant proteins that these five components are required for rapid and processive DNA synthesis on long single-stranded DNA templates. Subunit interactions known to occur in DNA polymerase III holoenzyme from mesophilic bacteria including δ-δ′ interaction, δδ′-τ/γ complex formation, and α-τ interaction, also occur within the Tth enzyme. As in mesophilic holoenzymes, in the presence of a primed DNA template, these subunits assemble into a stable initiation complex in an ATP-dependent manner. However, in contrast to replicative polymerases from mesophilic bacteria, Tth holoenzyme is efficient only at temperatures above 50 °C, both with regard to initiation complex formation and processive DNA synthesis. The minimalTth DNA polymerase III holoenzyme displays an elongation rate of 350 bp/s at 72 °C and a processivity of greater than 8.6 kilobases, the length of the template that is fully replicated after a single association event
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