1,762 research outputs found

    Streams and their future inhabitants

    Get PDF

    United States benefits of improved worldwide wheat crop information from a LANDSAT system

    Get PDF
    The value of worldwide information improvements on wheat crops, promised by LANDSAT, is measured in the context of world wheat markets. These benefits are based on current LANDSAT technical goals and assume that information is made available to all (United States and other countries) at the same time. A detailed empirical sample demonstration of the effect of improved information is given; the history of wheat commodity prices for 1971-72 is reconstructed and the price changes from improved vs. historical information are compared. The improved crop forecasting from a LANDSAT system assumed include wheat crop estimates of 90 percent accuracy for each major wheat producing region. Accurate, objective worldwide wheat crop information using space systems may have a very stabilizing influence on world commodity markets, in part making possible the establishment of long-term, stable trade relationships

    Learning from Degree-Seeking Older Adult Students in a University Library

    Get PDF
    Purpose – The purpose of this paper is to examine the use of library resources and services by degree-seeking older adult students (aged 50 years and over) and it is driven by the role of libraries in serving this often overlooked student population. Older adult students bring many benefits to the life of college campuses; nevertheless, many of these students also face challenges in meeting their information needs in academic libraries. Design/methodology/approach – The authors surveyed degree-seeking older adult students at a comprehensive metropolitan university in the western USA. Surveys were distributed to 579 students enrolled in the spring semester 2013, 134 students completed the 15-question online survey about the use of the library, information-seeking behaviors and use of other university services. Findings – The self-reported findings confirmed that the library meets most of the information needs of this student population. Students commented on satisfaction with the library services, barriers to using the library, areas in need of improvement and use of other university services. Research limitations/implications – Survey participants were gathered from one university and a corresponding sample size of 18-24-year-old students were not surveyed. More research is needed to demonstrate how this particular group varies from their traditional aged counterparts. Practical implications – This paper can be used as a starting point for future research into the information-seeking behaviors and needs of degree-seeking older adult students to develop greater understanding of this diverse population and their unique strengths and challenges. There is an absence in the literature on this demographic group in academic libraries. Originality/value – The article includes recommendations for further study and suggests outreach opportunities directed to older adult students that can also benefit the growing diversity of college students

    Effects of cascade-induced dislocation structures on the long-term microstructural evolution in tungsten

    Get PDF
    In recent years, a number of systematic investigations of high-energy collision cascades in tungsten employing advanced defect analysis tools have shown that interstitial clusters can form complex non-planar dislocation structures. These structures are sessile in nature and may potentially have a strong impact on the long-term evolution of the radiation microstructure. To clarify this aspect, we selected several representative primary damage states of cascades debris and performed annealing simulations using molecular dynamics (MD). We found that immobile complexes of non-planar dislocation structures (CDS) evolve into glissile and planar shaped 1/2 loops with an activation energy of similar to 1.5 eV. The CDS objects were implemented in an object kinetic Monte Carlo (OKMC) model accounting for the event of transformation into 1-D migrating loops, following the MD data. OKMC was then used to investigate the impact of the transformation event (and the associated activation energy) on the evolution of the microstructure.Peer reviewe

    Cytomegalovirus Late Protein pUL31 Alters Pre-rRNA Expression and Nuclear Organization during Infection

    Get PDF
    ABSTRACT The replication cycle of human cytomegalovirus (CMV) leads to drastic reorganization of domains in the host cell nucleus. However, the mechanisms involved and how these domains contribute to infection are not well understood. Our recent studies defining the CMV-induced nuclear proteome identified several viral proteins of unknown functions, including a protein encoded by the UL31 gene. We set out to define the role of UL31 in CMV replication. UL31 is predicted to encode a 74-kDa protein, referred to as pUL31, containing a bipartite nuclear localization signal, an intrinsically disordered region overlapping arginine-rich motifs, and a C-terminal dUTPase-like structure. We observed that pUL31 is expressed with true late kinetics and is localized to nucleolin-containing nuclear domains. However, pUL31 is excluded from the viral nuclear replication center. Nucleolin is a marker of nucleoli, which are membrane-less regions involved in regulating ribosome biosynthesis and cellular stress responses. Other CMV proteins associate with nucleoli, and we demonstrate that pUL31 specifically interacts with the viral protein, pUL76. Coexpression of both proteins altered pUL31 localization and nucleolar organization. During infection, pUL31 colocalizes with nucleolin but not the transcriptional activator, UBF. In the absence of pUL31, CMV fails to reorganize nucleolin and UBF and exhibits a replication defect at a low multiplicity of infection. Finally, we observed that pUL31 is necessary and sufficient to reduce pre-rRNA levels, and this was dependent on the dUTPase-like motif in pUL31. Our studies demonstrate that CMV pUL31 functions in regulating nucleolar biology and contributes to the reorganization of nucleoli during infection. IMPORTANCE Nucleolar biology is important during CMV infection with the nucleolar protein, with nucleolin playing a role in maintaining the architecture of the viral nuclear replication center. However, the extent of CMV-mediated regulation of nucleolar biology is not well established. Proteins within nucleoli regulate ribosome biosynthesis and p53-dependent cellular stress responses that are capable of inducing cell cycle arrest and/or apoptosis, and they are proposed targets for cancer therapies. This study establishes that CMV protein pUL31 is necessary and sufficient to regulate nucleolar biology involving the reorganization of nucleolar proteins. Understanding these processes will help define approaches to stimulate cellular intrinsic stress responses that are capable of inhibiting CMV infection
    • …
    corecore