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Herbivores are a diverse group of fauna that shape the distribution and composition of plant communities. In some cases, herbivory may prevent the re-establishment of submerged aquatic vegetation (SAV), such as Vallisneria americana, into systems. The goal of this study was to investigate the role and nature of herbivory on V. americana transplants with camera and transect surveys of grazing intensity and with field and laboratory grazing experiments using a suspected herbivore, the blue crab, Callinectes sapidus. Camera surveys recorded C. sapidus clipping and consuming shoots of V. americana for the first time. Grazing intensity surveys in low-salinity regions of the lower Chesapeake Bay indicated that the majority of V. americana transplants (50–75%) were clipped off at their base within one week of planting. Field and laboratory experiments demonstrated that C. sapidus clips and consumes V. americana as well as other rapidly colonizing, non-native SAV. Analysis of the gut contents of C. sapidus caught in SAV beds in the Chesapeake Bay revealed that SAV comprised 16% of their stomach contents, suggesting low levels of C. sapidus herbivory occurred over a wide area. Callinectes sapidus is yet another animal documented to consume SAV for some portion of their diet. These results also suggest that herbivores or omnivores, including C. sapidus, can serve as bottlenecks to recovery of SAV, like V. americana, in some areas. Herbivores may not serve as bottlenecks in other environments or to other SAV with more rapid plant growth or higher recruitment levels that may overcome grazing pressure.

Summary This study evaluated the benefits of ZOL versus placebo on health-related quality of life (HRQoL) among patients from HORIZON–RFT. At month 24 and end of the study visit, ZOL significantly improved patients’ overall health state compared to placebo as assessed by the EQ-5D VAS. Introduction To evaluate the benefits of zoledronic acid (ZOL) versus placebo on health-related quality of life (HRQoL) among patients from The Health Outcomes and Reduced Incidence With Zoledronic Acid Once Yearly Recurrent Fracture Trial (HORIZON–RFT). Methods In this randomized, double-blind, placebo-controlled trial, 2,127 patients were randomized to receive annual infusion of ZOL 5 mg ( n  = 1,065) or placebo ( n  = 1,062) within 90 days after surgical repair of low-trauma hip fracture. HRQoL was measured using EQ-5D Visual Analogue Scale (VAS) and utility scores (EuroQol instrument) at months 6, 12, 24, 36, and end of the study visit. Analysis of covariance model included baseline EQ-5D value, region, and treatment as explanatory variables. Results At baseline, patients (mean age 75 years; 24% men and 76% women) were well matched between treatment groups with mean EQ-5D VAS of 65.82 in ZOL and 65.70 in placebo group. At the end of the study, mean change from baseline in EQ-5D VAS was greater for ZOL vs. placebo in all patients (7.67 ± 0.56 vs. 5.42 ± 0.56), and in subgroups of patients experiencing clinical vertebral fractures (8.86 ± 4.91 vs. −1.69 ± 3.42), non-vertebral fractures (5.03 ± 2.48 vs. −1.07 ± 2.16), and clinical fractures (5.19 ± 2.25 vs . − 0.72 ± 1.82) with treatment difference significantly in favor of ZOL. EQ-5D utility scores were comparable for ZOL and placebo groups, but more patients on placebo consistently had extreme difficulty in mobility (1.74% for ZOL vs. 2.13% for placebo; p =  0.6238), self-care (4.92% vs. 6.69%; p  = 0.1013), and usual activities (10.28% vs. 12.91%; p =  0.0775). Conclusion ZOL significantly improves HRQoL in patients with low-trauma hip fracture.

Blood cell production originates from a rare population of multipotent, self-renewing stem cells. A genome-wide gene expression analysis was performed in order to define regulatory pathways in stem cells as well as their global genetic program. Subtracted complementary DNA libraries from highly purified murine fetal liver stem cells were analyzed with bioinformatic and array hybridization strategies. A large percentage of the several thousand gene products that have been characterized correspond to previously undescribed molecules with properties suggestive of regulatory functions. The complete data, available in a biological process-oriented database, represent the molecular phenotype of the hematopoietic stem cell.

Prediction of ice formation in clouds presents one of the grand challenges in the atmospheric sciences. Immersion freezing initiated by ice-nucleating particles (INPs) is the dominant pathway of primary ice crystal formation in mixed-phase clouds, where supercooled water droplets and ice crystals coexist, with important implications for the hydrological cycle and climate. However, derivation of INP number concentrations from an ambient aerosol population in cloud-resolving and climate models remains highly uncertain. We conducted an aerosol–ice formation closure pilot study using a field-observational approach to evaluate the predictive capability of immersion freezing INPs. The closure study relies on collocated measurements of the ambient size-resolved and single-particle composition and INP number concentrations. The acquired particle data serve as input in several immersion freezing parameterizations, which are employed in cloud-resolving and climate models, for prediction of INP number concentrations. We discuss in detail one closure case study in which a front passed through the measurement site, resulting in a change of ambient particle and INP populations. We achieved closure in some circumstances within uncertainties, but we emphasize the need for freezing parameterization of potentially missing INP types and evaluation of the choice of parameterization to be employed. Overall, this closure pilot study aims to assess the level of parameter details and measurement strategies needed to achieve aerosol–ice formation closure. The closure approach is designed to accurately guide immersion freezing schemes in models, and ultimately identify the leading causes for climate model bias in INP predictions.

The immortalized murine stromal cell line AFT024 has been reported to maintain human hematopoietic progenitors in an undifferentiated state in vitro. In the current studies the beige/nude/xid (bnx) mouse in vivo xenograft model was used to examine the engraftment and multilineage generative potential of human hematopoietic progenitors after 2-3 weeks growth on AFT024 stroma, in comparison to primary stromal monolayers derived from post-natal human bone marrow. Eight to 12 months after transplantation of human CD34+CD38- cells from umbilical cord blood, cultured on AFT024 vs human stroma for 2-3 weeks, the murine bone marrow was harvested and analyzed for the presence of human myeloid and lymphoid cells. The mean percent engraftment of total human hematopoietic cells in the murine marrow was significantly higher after co-cultivation on AFT024 than on human stroma. Human myeloid and lymphoid lineage cells were detected in all mice. However, engraftment of myeloid lineage cells (CD33+), B lymphoid (CD19+), and T lymphoid cells (CD4+and CD8+) were significantly higher after co-cultivation of the human cells on AFT024 than on human stroma, prior to transplantation. Interestingly, the length of time in culture did not significantly affect the engraftment of the myeloid and T lymphoid lineage progenitors, but the percentage of B lymphoid lineage engraftment decreased significantly between 2 and 3 weeks of co-cultivation on both types of stroma. Cells with a primitive phenotype (CD45+/CD34-/CD38- and CD45+/CD34-/lin-) and cells with the capacity to generate secondary human CFU after recovery from the bnx bone marrow were maintained at significantly higher levels during culture on AFT024 stroma than on human stroma. The current studies demonstrate that the AFT024 murine stromal cell line supports the ex vivo survival and maintenance of human hematopoietic progenitors that are capable of long-term multilineage reconstitution for 2-3 weeks ex vivo, to levels superior to those that can be obtained using human stromal cells.

To assess Canadian physicians' confidence in, attitudes about and preferences regarding clinical practice guidelines. Cross-sectional, self-administered mailed survey. Stratified random sample of 3000 Canadian physicians; 1878 (62.6%) responded. Canada. Physicians' use of various information sources; familiarity with and confidence in guidelines; attitudes about guidelines and their effect on medical care; rating of importance of guidelines and other sources of information in clinical decision-making; rating of importance of various considerations in deciding whether to adopt a set of guidelines; and rating of usefulness of different formats for presenting guidelines. In all, 52% of the respondents reported using guidelines at least monthly, substantially less frequently than traditional information sources. Most of the respondents expressed confidence in guidelines issued by various physician organizations, but 51% to 77% were not confident in guidelines issued by federal or provincial health ministries or by health insurance plans. The respondents were generally positive about guidelines (e.g., over 50% strongly agreed that they are a convenient source of advice and good educational tools); however, 22% to 26% had concerns about loss of autonomy, the rigidity of guidelines and decreased satisfaction with medical practice. Endorsement by respected colleagues or major organizations was identified as very important by 78% and 62% of the respondents respectively in deciding whether to adopt a set of guidelines in their practice. User friendliness of the guidelines format was thought to be very important by 62%; short pamphlets, manuals summarizing a number of guidelines, journal articles and pocket cards summarizing guidelines were the preferred formats (identified as most useful by 50% to 62% of the respondents). Canadian physicians, although generally positive about guidelines and confident in those developed by clinicians, have not yet integrated the use of guidelines into their practices to a large extent. Our results suggest that respected organizations and opinion leaders should be involved in the development of guidelines and that the acceptability of any proposed format and medium for guidelines presentation should be pretested.

Seagrasses rely on both vegetative (rhizome elongation) and sexual (seeds) propagation for maintenance of existing beds and colonization of new areas. Yet mechanisms of seed dispersal and survival of seeds in new areas remain poorly described. We conducted seed dispersal experiments in the field and laboratory to better describe seed dispersal characteristics in one species, Zostera marina L. (eelgrass), the dominant seagrass species in the temperate zone of the United States, Japan, and Europe. Seeds were broadcast by hand into unvegetated 5 m diameter plots at three locations over 3 yr (1989—1991) in the York River, Virginia (Chesapeake Bay). These sites had been previously vegetated but were devoid of any vegetation prior to (since 1972) and during the course of the experiments. Resultant seedling distributions closely matched broadcast patterns, with 80% of all seedlings found within the 5 m diameter plots, despite the fact that geophysical processes would appear sufficient to transport seeds greater distances. Wind records for the 2—mo period between seed broadcasting and germination revealed time—averaged wind speeds in excess of 40 km/h on > 12 d in each of the 3 yr and galeforce winds (17 km/h) in 2 of 3 yr. A three—dimensional hydrographic computer simulation model of the York River provided instantaneous current velocity estimates from which maximum bottom shear velocities (u*) in the study area were approximated (flood tide: 1.26 cm/s, ebb tide: 1.20 cm/s). These estimates exceeded the critical erosion threshold (U*c ᵣ ᵢ ₜ = 0.7 cm/s) for Z. marina seeds determined from laboratory flume experiments. We postulate that small—scale topographic features on the bottom (burrows, pits, mounds, ripples) shield the seeds from the flow. Our results suggest that seeds settle rapidly, dispersing only up to a few metres under the influence of currents and become rapidly incorporated into the sediment. The limited dispersal capabilities of seeds underscore the need to address restoration goals and questions of seagrass ecology in the context of landscape—scale distributional patterns and metapopulation analyses.

The overall goal of the Chesapeake Bay National Estuarine Research Reserve in Virginia (CBNERRVA) research and monitoring program is to promote, coordinate and conduct research and monitoring to enhance the scientific understanding and management of the York River and southern Chesapeake Bay coastal ecosystems. The regions of greatest scientific emphasis are located within four Reserve sites located along the York-Pamunkey River estuarine system. Primary research and environmental monitoring areas include: estuarine and shallow water environments including benthic communities, submerged aquatic vegetation and emergent wetlands habitats, open water regions and adjacent watersheds and air sheds. Both national priority (NOAA) and Chesapeake Bay specific (Chesapeake Bay Program) research focus areas are pursued within the Research Reserve with goals to: enhance scientific understanding of coastal ecosystems, surrounding environments and the natural and human processes influencing such systems; and, promote the effective management and conservation of natural and cultural coastal resources through informed decision-making. A System-wide Monitoring Program (SWMP) initiated by the Estuarine Reserves Division (ERD) of NOAA provides standardized data on national estuarine environmental trends through similar measurements of abiotic and biotic variables as well as watershed and land use classifications and measurements at each of the 27 Reserves. Data are compiled electronically at a central data management location and are available via web interface (www.vecos.org). Ongoing York River monitoring programs at the CBNERRVA reserve sites include; meteorological and streamflow monitoring, water quality monitoring and biological monitoring are available through the Reserve or via web interface. Multi-parameter water quality, in situ monitors at both fixed and buoyed stations, point sampling and continuous underway flow-through monitoring form the basis of the water quality monitoring program. Research opportunities at Reserve sites are available to any qualified scientist, academician or student affiliated with a university, college or school, non-profit organizations, and non-academic research institutions. In addition, the Reserve sponsors competitive graduate research fellowships through the NERRS Graduate Research Fellowship (GRF) Program for student research in the York River system.

The goal of this study was to evaluate if differences in culture conditions used in long-term culture assays affect enumeration of LTC-IC in freshly sorted or ex vivo expanded CD34+/HLA-DRdim/CD2-/CD7- (34+/Lin-) cells. The variables examined included different stromal feeders (murine bone marrow fibroblast cell line, M2-10B4 and murine fetal liver cell line, AFT024) and presence or absence of cytokines (MIP-1alpha + IL-3). The absolute LTC-IC frequency in 34+/Lin- cells measured in limiting dilution assays (LDA) on AFT024 (4.45 +/- 0.69%) was significantly higher than in M2-10B4 (1.45 +/- 0.20%) LDA. Addition of MIP-1alpha and IL-3 to AFT024 LDA increased the measured LTC-IC frequency to 6.8 +/- 0.9%. We also determined the fraction of LTC-IC that persisted after 34+/Lin cells were cultured for 5 weeks by replating progeny in the three LDA readout systems. The measured LTC-IC maintenance was significantly lower when M2-10B4 LDA (13.1 +/- 3.5%, P < 0.05) were used compared with AFT024 LDA (36.6 +/- 5.5%) or AFT024 LDA supplemented with MIP-1alpha and IL-3 (29.1 +/- 6.3%). Thus, the number of LTC-IC measured in freshly sorted 34+ cells depends on the stromal feeder used in LDA assays. Furthermore, and most important, assessment of LTC-IC expansion or maintenance may vary significantly depending on the type of stromal feeder used to enumerate LTC-IC.