Digital Commons Network^™

Phenological Synchrony Affects Interaction Strength Of An Exotic Weevil With Platte Thistle, A Native Host Plant, F. Leland Russell, Svata M. Louda

Svata M. Louda Publications

Phenological synchrony of a consumer population with its resource populations is expected to affect interaction intensity. We quantified phenological variation and synchrony of populations of an invasive Eurasian flower head weevil, Rhinocyllus conicus, that consumes florets, ovules, and seeds of developing flower heads of a native North American thistle, Cirsium canescens, in Sand Hills prairie in Nebraska, USA. Variation in timing of adult activity among weevil populations was larger than variation in timing of flower head development among C. canescens populations, and it drove the observed variation in the phenological synchrony between weevil and host plant populations. Furthermore, …

Local- Vs. Landscape-Scale Indirect Effects Of An Invasive Weed On Native Plants, Tatyana A. Rand, F. Leland Russell, Svata M. Louda

Svata M. Louda Publications

Insect-mediated indirect interactions between native plant species recently have been shown to be important determinants of plant performance in a number of ecological communities. However, the potential indirect effects of exotic plant invasion on native plant species are not well understood. We examined whether the presence or proximity of the targeted exotic weed, musk thistle, influences the magnitude of attack on native thistles by the introduced biological control, flowerhead weevil. At the local scale, we quantified weevil egg densities on heads of the native wavyleaf thistle growing at different distances (0 to 100 m) from patches of the exotic thistle. …

Weeds [From Encyclopedia Of The Great Plains], Svata M. Louda

Svata M. Louda Publications

According to the U.S. Department of Agriculture, countless hours and millions of dollars are spent each year to control weeds, and millions more--hours and dollars--are lost in yield reductions. However, what exactly is a weed? And what makes a plant a weed? Many people are surprised to learn that a weed is technically "a plant out of place." So one person's weed can be someone else's salad green, pharmaceutical, transgenic crop, or wildflower! What are the characteristics of plants that often grow out of place? One characteristic is a tendency to reach high numbers rapidly and to replace or slow …

High Phosphate (Up To 600 Mm) Induces Pseudohyphal Development In Five Wild Type Candida Albicans, Jacob M. Hornby, Raluca Dumitru, Kenneth Nickerson

Kenneth Nickerson Papers

A method is described for the formation of nearly 100% pseudohyphae populations of wild-type Candida albicans A72. The method employs fungal growth at 37 °C (ca. 5×10⁶ cells/ml) in a glucose–proline–N-acetyl-glucosamine medium supplemented with up to 600 mM phosphate (KH₂PO₄/K₂HPO₄ 1:1) at pH 6.5. Four other strains of C. albicans (MEN, 10261, SG5314 and CAI-4) also formed pseudohyphae under these conditions, although the phosphate response profiles differed in the concentration required for each strain to form pseudohyphae.

The Geometry Of Foraging Patterns: Components Of Thoroughness In Random Searching, Alan B. Bond

Papers in Behavior in Biological Sciences

A Monte Carlo simulation of the movements of a randomly-searching predator was used to develop a novel geometrical measure, the "thoroughness" of the search, and to investigate the effects of meander, turn asymmetry, and path length. Thoroughness varied directly with the meander and the square of the asymmetry measure and remained relatively invariant with path length. The regularity of its relationship to the generating parameters of the search and the ease with which it may be estimated from field data recommend thoroughness for use in characterizing empirical search patterns and in testing for the occurrence of systematic searching.

The Southwestern Association Of Parasitologists: The First 35 Years: 1967–2002, Donald W. Duszynski

Harold W. Manter Laboratory of Parasitology: Faculty Publications

First two paragraphs:

It is likely that the idea to organize southwestern parasitologists into a regional group originated over cocktails one night in the late 1950s during a regional or national meeting. What is clear is that two men—Drs. Robert E. Kuntz and Donald V. Moore— were instrumental in turning the idea into what has become, in reality, the Southwestern Association of Parasitologists (SWAP). Dr. J. Teague Self (personal communication, 1981) stated, “The beginning of SWAP was an idea of Robert Kuntz who felt that something could be gained if several of us here in the southwest could get together …

Some Aspects Of The Biology And Life History Of Bothitrema Bothi (Monogenea: Bothitrematidae) From The Flounder Scophthalmus Aquosus (Bothidae) From New Jersey, Usa, Sherman S. Hendrix

Harold W. Manter Laboratory of Parasitology: Faculty Publications

Bothitrema bothi (MacCallum, 1913), a monopisthocotylean monogenean (Bothitrematidae) found on gills and occasionally on the olfactory rosette within the nares of the bothid flounder, Scophthalmus aquosus (Mitchill, 1815), is distributed along the Atlantic coast of the USA from Woods Hole, Massachusetts to Delaware Bay. This study details aspects of the morphology, microecology and biology of the oncomiracidium, juvenile and adult. Adult worms occur almost exclusively between rakers on the first and second gill arches while juveniles occupy secondary gill filaments. Analysis of variance revealed significant arch, side and position effects. Worm attachment and position is maintained largely by suction generated …

Hydrologic Variation During The Last 170,000 Years In The Southern Hemisphere Tropics Of South America, Sherilyn C. Fritz, Paul A. Baker, Tim K. Lowenstein, Geoffrey O. Seltzer, Catherine A. Rigsby, Gary S. Dwyer, Pedro M. Tapia, Kimberly K. Arnold, Teh-Lung Ku, Shangde Luo

Department of Earth and Atmospheric Sciences: Faculty Publications

Despite the hypothesized importance of the tropics in the global climate system, few tropical paleoclimatic records extend to periods earlier than the last glacial maximum (LGM), about 20,000 years before present. We present a well-dated 170,000-year time series of hydrologic variation from the southern hemisphere tropics of South America that extends from modern times through most of the penultimate glacial period. Alternating mud and salt units in a core from Salar de Uyuni, Bolivia reflect alternations between wet and dry periods. The most striking feature of the sequence is that the duration of paleolakes increased in the late Quaternary. This …

A Major Pitfall In The Search Strategy On Pubmed, Ghazi O. Tadmouri, Nisrine Bissar-Tadmouri

Saudi Medical Journal

No abstract provided.

Cancer-Related Anemia, Hikmat N. Abdel-Razeq

Saudi Medical Journal

Anemia is the most common hematological abnormality in cancer patients, unfortunately, it is often under-recognized and under-treated. The pathogenesis of cancer anemia is complex and most of the time multifactorial; involving factors related to the tumor itself or its therapy. While anemia can present in a wide range of symptoms, involving almost every organ, it is believed that it contributes much to cancer-related fatigue, one of the most common symptoms in cancer patients. In addition, there is increasing evidence to suggest that anemia is an independent factor adversely affecting tumor response and patient survival. While blood transfusion was the only …

Thyroid Cancer In Yemen, Yasser A. Abdulmughni, Mohammed A. Al-Hureibi, Khalid A. Al-Hureibi, Mohammed A. Ghafoor, Ali H. Al-Wadan, Yahia A. Al-Hureibi

Saudi Medical Journal

OBJECTIVE: To evaluate the characteristics of thyroid cancer (TC) patients in regard to demographic distribution, histological variants, mode of presentation and modalities of diagnosis and treatment. METHODS: We retrospectively audited the records of 97 consecutive cases with histologically proved thyroid cancer between 1997 and 2001 presenting to the Kuwait University Hospital, Sana9a, Yemen. RESULTS: Patients with TC in this study comprise 17.7% of goiter patients who were admitted at the same period. Females constituted 89.7% (n=87), and males 10.3% (n=10). The average age of diagnosis was 38.4 years. More than two thirds were at the age of <40. Among patients with goiter, the percentage of carcinoma was higher in the following groups, males (37.9% versus 16.6%, p=0.028), patients aged >47 (25.8% versus …

Dementia In Qatar, Ahmad I. Hamad, Mohammed A. Ibrahim, Essa M. Sulaiti

Saudi Medical Journal

OBJECTIVE: Dementia is a major public health problem among the elderly in developed countries and a growing problem in the underdeveloped countries. There are no published data on dementia in any of the Arabic countries. The aim of this study was to determine the different sub-types of dementia among Qataris. METHODS: A retrospective and prospective ongoing hospital-based study in which all medical records of the patients with diagnosis of dementia seen at the Hamad General Hospital, Doha, Qatar, between June 1997 and June 2003, whether inpatient or outpatient were reviewed. Dementia was defined according to diagnostic and statistical manual (DSM) …

Hemorrhagic Episodes In Hemophiliacs Simulating Abdominal Surgical Emergencies, Mohammad E. Rabie, Abdul-Rahman E. Al-Tayeb, Mubarak H. Zafer, Anwar K. Sheikha

Saudi Medical Journal

Hemophiliacs are subjected to develop episodes of spontaneous bleeding at different sites of the body, primarily the knees. On occasions, such episodes affect the abdomen. The picture engendered in such cases may mimic that of an abdominal emergency requiring surgical intervention. Such ill advised and unwarranted intervention may end with the patient9s death. With the proper employment of radiology, the correct diagnosis may be reached and consequently, conservative treatment, in which factor VIII plays the major role, instituted. Here, we describe the clinical course of 2 patients with hemophilia A who suffered bleeding in the abdomen and were treated conservatively …

The Ecology Of Interorganizational Information Sharing, Jane Fedorowicz, Janis L. Gogan, Amy W. Ray

Journal of International Technology and Information Management

Increasingly, companies use interorganizational information systems to support business process partnerships, such as automatic replenishment systems and other supply chain initiatives, invoicing and payments, and insurance claims processing. Inter-firm networking in turn can increase the visibility of information generated and used by business partners. These business partners may experience intended and unintended impacts from the changes in the partnering relationship, in effect altering the ecology of the organization. Yet IT researchers rarely study an organization’s ecology, focusing instead on impacts upon internal processes. Our goal in this paper is to propose a definition of interorganizational information ecology, to provide IT …

A Conceptual Framework For E-Branding Strategies In The Non-Profit Sector, Horst Treiblmaier, Irene Pollach, Arne Floh

Journal of International Technology and Information Management

E-branding provides non-profit organizations (NPOs) with new opportunities to communicate their missions, which is of paramount importance in a market segment that competes for donations and voluntary labor. Since successful e-branding is determined by both internal and external communication strategies, we developed a framework which explains the interdependency of these two factors in NPOs. Our findings are based on qualitative interview data and a website analysis of eleven Austrian NPOs. The NPOs' internal and external e-communication strategies are categorized into three successive levels each and combined in a two-dimensional grid, which shows how NPOs integrate their communication strategies.

Ecological Effects Of Transgenic Crops And The Escape Of Transgenes Into Wild Populations, Diana Pilson, Holly R. Prendeville

School of Biological Sciences: Faculty Publications

Ecological risks associated with the release of transgenic crops include nontarget effects of the crop and the escape of transgenes into wild populations. Nontarget effects can be of two sorts: (a) unintended negative effects on species that do not reduce yield and (b) greater persistence of the crop in feral populations. Conventional agricultural methods, such as herbicide and pesticide application, have large and well- documented nontarget effects. To the extent that transgenes have more specific target effects, transgenic crops may have fewer nontarget effects. The escape of transgenes into wild populations, via hybridization and introgression, could …

Landscape Vs. Local Habitat Scale Influences To Insect Communities From Tallgrass Prairie Remnants, Kristal J.L. Stoner, Anthony Joern

School of Biological Sciences: Faculty Publications

Habitat loss and fragmentation currently threaten ecosystems worldwide, yet remain difficult to quantify because within-fragment habitat and landscape-scale influences often interact in unique ways. Although individual species respond to fragmentation differently, large-scale conservation planning must unavoidably target multiple species. Although information on a population’s response to fragmentation is critical, and measurements of species richness provide useful insights, exclusive reliance on these responses may mask important information about the taxonomic composition of assemblages in response to fragmentation. The North American tallgrass prairie ecosystem is one of the most threatened and fragmented ecosystems in the world, and insects are significant contributors to …

Mark–Recapture And Behavioral Ecology: A Case Study Of Cliff Swallows, C. R. Brown, Mary Bomberger Brown

School of Biological Sciences: Faculty Publications

Mark–recapture and behavioral ecology: a case study of Cliff Swallows.— Mark–recapture and the statistical analysis methods associated with it offer great potential for investigating fitness components associated with particular behavioral traits. However, few behavioral ecologists have used these techniques. We illustrate the insights that have come from a long–term mark–recapture study of social behavior in Cliff Swallows (Petrochelidon pyrrhonota). The number of transient swallows passing through a colony per hour increased with colony size and was responsible in part for increased rates of ectoparasite introduction from outside the group into the larger colonies. Annual survival probabilities of …

Juvenile And Adult Survival In The Sociable Weaver (Philetairus Socius), A Southern-Temperate Colonial Cooperative Breeder In Africa, Rita Covas, Charles R. Brown, Mark D. Anderson, Mary Bomberger Brown

School of Biological Sciences: Faculty Publications

We used capture–recapture analyses to describe juvenile and adult survival from 1993 to 2001 in a population of Sociable Weavers (Philetairus socius), a colonial, cooperatively breeding passerine of southern Africa. We examined temporal variation in survival and the role that the breeding season’s length and environmental factors play in determining survival patterns in the population. Annual survival probability (mean ± SE) was 0.66 ± 0.02. In contrast to most passerines, juveniles and adults had similar survival probabilities; survival rates did not vary significantly between years. We found no relationship among temperature, rainfall, and survival. Relatively high survival rates …

Group Size And Ectoparasitism Affect Daily Survival Probability In A Colonial Bird, Charles R. Brown, Mary Bomberger Brown

School of Biological Sciences: Faculty Publications

Little is known in general about how group size or ectoparasitism affect survival in colonial animals. We estimated daily within-season survival probabilities for nesting adult and recently fledged juvenile cliff swallows (Petrochelidon pyrrhonota) at 239 colonies from 1983 to 2003 in southwestern Nebraska, USA. Some colonies had been fumigated to remove ectoparasites. We conducted mark-recapture at each colony site to estimate daily survival. There were no systematic differences between males and females in daily survival. Adults and juveniles occupying parasite-free colonies had, on average, 4.4% and 62.2% greater daily survival, respectively, than their counterparts in naturally infested colonies. …

Preface To Nanoscale Characterization Of Ferroelectric Materials: Scanning Probe Microscopy Approach, Mann Alexe, Alexei Gruverman

Alexei Gruverman Publications

Among the main trends in our daily society is a drive for smaller, faster, cheaper, smarter computers with ever-increasing memories. To sustain this drive the computer industry is turning to nanotechnology as a source of new processes and functional materials, which can be used in high-performance high-density electronic systems. Researchers and engineers have been focusing on ferroelectric materials for a long time due to their unique combination of physical properties. The ability of ferroelectrics to transform electromagnetic, thermal, and mechanical energy into electrical charge has been used in a number of electronic applications, most recently in nonvolatile computer memories. Classical …

Deletion Of The Δ12-Oleic Acid Desaturase Gene Of A Nonaflatoxigenic Aspergillus Parasiticus Field Isolate Affects Conidiation And Sclerotial Development, Perng Kuang Chang, Richard A. Wilson, Nancy P. Keller, Thomas E. Cleveland

Fungal Molecular Plant-Microbe Interactions

Aims: To investigate how linoleic acid affects conidial production and sclerotial development in a strictly mitotic Aspergillus parasiticus field isolate as related to improving biocompetitivity of atoxigenic Aspergillus species.

Methods and Results: We disrupted A. parasiticus Δ12-oleic acid desaturase gene (odeA) responsible for the conversion of oleic acid to linoleic acid. We examined conidiation and sclerotial development of SRRC 2043 and three isogenic mutant strains deleted for the odeA gene (DodeA), either with or without supplementing linoleic acid, on one complex potato dextrose agar (PDA) medium and on two defined media: nitrate-containing Czapek agar (CZ) and Cove’s ammonium …

Characterization Of The Aspergillus Parasiticus Δ12-Desaturase Gene: A Role For Lipid Metabolism In The Aspergillus–Seed Interaction, Richard A. Wilson, Ana M. Calvo, Perng-Kuang Chang, Nancy P. Keller

Fungal Molecular Plant-Microbe Interactions

In the mycotoxigenic oilseed pathogens Aspergillus flavus and Aspergillus parasiticus and the model filamentous fungus Aspergillus nidulans, unsaturated fatty acids and their derivatives act as important developmental signals that affect asexual conidiospore, sexual ascospore and/or sclerotial development. To dissect the relationship between lipid metabolism and fungal development, an A. parasiticus Δ¹²-desaturase mutant that was unable to convert oleic acid to linoleic acid and was thus impaired in polyunsaturated fatty acid biosynthesis was generated. The Δ¹²-desaturase mutant demonstrates delayed spore germination, a twofold reduction in growth, a reduced level of conidiation and complete loss of sclerotial …

Two Δ9-Stearic Acid Desaturases Are Required For Aspergillus Nidulans Growth And Development, Richard A. Wilson, Perng-Kuang Chang, Agnieszka Dobrzyn, James B. Ntambi, Robert Zarnowski, Nancy P. Keller

Fungal Molecular Plant-Microbe Interactions

Unsaturated fatty acids are important constituents of all cell membranes and are required for normal growth. In the filamentous fungus Aspergillus nidulans, unsaturated fatty acids and their derivatives also influence asexual (conidial) and sexual (ascospore) sporulation processes. To investigate the relationship between fatty acid metabolism and fungal development, we disrupted the A. nidulans sdeA and sdeB genes, both encoding Δ9-stearic acid desaturases responsible for the conversion of palmitic acid (16:0) and stearic acid (18:0) to palmitoleic acid (16:1) and oleic acid (18:1). The effects of sdeA deletion on development were profound, such that growth, conidial and ascospore production were …

Drive, Incentive, And Reinforcement: The Antecedents And Consequences Of Motivation, Roy Wise

Department of Psychology: Faculty Publications

The aim of scientific explanation is to characterize the important antecedents of observable (or at least objectively confirmable) events. Explanations of behavior in terms of motivational states are appeals to unobservable, internal events for interpretations of behavior that is variable under apparently constant external stimulus conditions (see, e.g., Brown, 1953; Hinde, 1960). To be identified as the cause of a behavior, the unobservable event or condition must preexist the behavioral event to be explained. A behavior cannot be explained by its consequences, though it may be explained as a consequence of similar events in the animal's history. Scientific explanation involves …

Why Be Nice? Psychological Constraints On The Evolution Of Cooperation, Jeffrey R. Stevens, Marc D. Hauser

Department of Psychology: Faculty Publications

Animals often aid others without gaining any immediate benefits. Although these acts seem to reduce the donor’s fitness, they are only apparently altruistic. Donors typically help because they or their kin receive future benefits or avoid costly punishment. Reciprocal altruism— alternating the roles of donor and recipient—has been a well-studied form of cooperation among non-kin because of its intuitive appeal in explaining human cooperation. Despite immense theoretical interest, little empirical evidence substantiates the biological importance of reciprocal altruism in non-human animals. We propose that this is because psychological mechanisms constrain its application in cooperative contexts. In particular, we contend that …

Caregiving Through A Relationship Lens In Reggio Emilia And A Lab School In Canada, Carolyn P. Edwards, Alex Dougherty

Department of Psychology: Faculty Publications

In recent years developmental scientists have described the tasks of relationship-building that contribute to early development: security and attachment, self-recognition and validation, mutuality and companionship, passionate experience, identification and group belonging, and giving care to others. Relationship-building begins within the family, then, in extending it outside the family, early education can play a key role. This selection contains two parts. The first piece describes the kinds of benefits these widening relationships can provide for very young children and outlines some specific steps that educators in Reggio Emilia, Italy, have taken to ensure the best, most "amiable" environments. The second piece, …

High Resolution Paleoceanography Of The Guaymas Basin, Gulf Of California, During The Past 15 000 Years, John A. Barron, David Bukry, James L. Bischoff

United States Geological Survey: Staff Publications

Deep Sea Drilling Project Site 480 (27°54.10’N, 111°39.34’W; 655 m water depth) contains a high resolution record of paleoceanographic change of the past 15 000 years for the Guaymas Basin, a region of very high diatom productivity within the central Gulf of California. Analyses of diatoms and silicoflagellates were completed on samples spaced every 40-50 yr, whereas ICP-AES geochemical analyses were completed on alternate samples (sample spacing 80-100 yr). The Bolling-Allerod interval (14.6-12.9 ka) (note, ka refers to 1000 calendar years BP throughout this report) is characterized by an increase in biogenic silica and a decline in calcium carbonate relative …

The History Of Recent Limnological Changes And Human Impact On Upper Klamath Lake, Oregon, J. Platt Bradbury, Steven M. Colman, Richard L. Reynolds

United States Geological Survey: Staff Publications

Hypereutrophic Upper Klamath Lake has been studied for almost 50 years to evaluate the nature, cause, and effects of its very productive waters. Mitigation of undesirable effects of massive cyanobacterial blooms requires understanding their modern causes as well as their history. Knowledge of the pre-settlement natural limnology of this system can provide guidelines for lake restoration and management of land and water use strategies to maximize the benefits of this aquatic resource. This investigation uses a paleolimnological approach to document the nature and chronology of limnological and biological changes in Upper Klamath Lake for the past 200 years, covering the …

Geochemical Cycles In Sediments Deposited On The Slopes Of The Guaymas And Carmen Basins Of The Gulf Of California Over The Last 180 Years, Walter E. Dean, Carol Prideb, Robert Thunell

United States Geological Survey: Staff Publications

Sediments deposited on the slopes of the Guaymas and Carmen Basins in the central Gulf of California were recovered in two box cores. Q-mode factor analyses identified detrital-clastic, carbonate, and redox associations in the elemental composition of these sediments. The detrital-clastic fraction appears to contain two source components, a more mafic component presumably derived from the Sierra Madre Occidental along the west coast of Mexico, and a more felsic component most likely derived from sedimentary rocks (mostly sandstones) of the Colorado Plateau and delivered by the Colorado River. The sediments also contain significant siliceous biogenic components and minor calcareous biogenic …