Changes in the appearance of Malvaviscus arboreus flowers are associated with changes in nectar reward. Nectar volumes found in day-1 flowers were generally larger and less variable than volumes ...found in day-2 flowers. Observations of nonterritorial Ruby-throated and Black-chinned hummingbirds (Archilochus colubris and A. alexandri) showed that they distinguished between flowers and preferentially visited the more profitable day-1 flowers. When sucrose solution was added to all day-2 flowers in one Malvaviscus patch, the birds stopped discriminating between flowers the first morning of floral enrichment. These results indicate that the birds can respond to fairly subtle visual cues when determining the appropriate flowers to visit. The ultimate factor in determining which flowers to continue visiting, however, is the nectar reward. The birds learned to respond differently to the same proximate cue when it was advantageous to do so.
This document summarizes recent achievements of the RHIC spin program and their impact on our understanding of the nucleon's spin structure, i.e. the individual parton (quark and gluon) contributions ...to the helicity structure of the nucleon and to understand the origin of the transverse spin phenomena. Open questions are identified and a suite of future measurements with polarized beams at RHIC to address them is laid out. Machine and detector requirements and upgrades are briefly discussed.
A progress report is given for the various components of the STAR detector system. We report on the recent developments in the detector proto-typing and construction, with an emphasis on the main ...TPC, recent TPC cosmic ray testing and shipping to Brookhaven National Laboratory
Immunochemical and biological characterization was performed of an antigen-binding factor derived from culture supernatants of T cells from mice infected 4 days previously with the intestinal ...helminth Trichinella spiralis. Affinity chromatography with T. spiralis antigen resulted in the purification of a protein, provisionally designated Trichinella factor (Tric-F), that shared antigenic and other properties with a known T-cell-derived antigen-binding factor of different antigenic specificity, picryl chloride factor, which mediates an early 2-hour component of contact sensitivity. Tric-F lacked determinants of immunoglobulins and possessed determinants shared by other antigen-specific T cell factors, as determined by ELISA and antibody affinity chromatography. Biological activity of Tric-F was assayed in vivo and in vitro. Mice injected intravenously with Tric-F developed an antigen-specific early 2-hour ear swelling response following local challenge with T. spiralis antigen. These results corresponded to delayed-type hypersensitivity responses in the ears of T. spiralis-infected mice that comprised early 2-hour and late classical 24-hour responses. In vitro, Tric-F induced serotonin release by mast cells in the presence of T. spiralis antigen. Mast cells sensitized with Tric-F formed rosettes with antigen-coated sheep erythrocytes. It is suggested that Tric-F, an antigen-binding molecule that is T-cell-derived, mediates the early 2-hour component of delayed-type hypersensitivity and is involved in the initiation and regulation of T-cell-mediated intestinal inflammation during a T. spiralis infection in mice.
The recent identification of a T-cell-derived antigen-binding molecule (TABM), Trichinella spiralis factor (Tric-F), isolated from culture supernatants of lymphoid cells from mice infected with the ...intestinal helminth T. spiralis, has led to investigation of the ability of Tric-F to induce a T-cell-dependent feedback circuit that ultimately suppresses the production of other TABMs with similar (isotype-like) features. This form of regulation that has been identified in contact hypersensitivity and in delayed-type hypersensitivity (DTH) responses to tumor cells, was shown not to be antigen-specific but to be DTH-specific. Injection of mice with the TABM called picryl chloride factor (PCl-F) induced suppression of the production of DTH-initiating TABMs of other antigenic specificities. In this study, we report that intravenous injection of mice with Tric-F or PCl-F, 8 days before an oral infection with T. spiralis, induced suppressor cells that inhibited the T-cell-dependent influx into the gut of inflammatory cells, comprising mast cells and eosinophils. Similar results were obtained when the mice were skin sensitized with PCl 8 days prior to a T. spiralis infection, i.e. in a system where TABMs are known to be produced. The phenotype of these suppressor cells was Lyt-1-2+. This suppression preferentially affected the parasite-induced DTH-like response in the gut. In contrast, increased levels of IgA plasma cells in the gut, and worm expulsion were not affected by these treatments. In reciprocal experiments, intravenous injection of Tric-F, or PCl-F, or an oral infection with T. spiralis (that results in the production of TABMs) given 8 days before contact sensitizing mice with PCl, resulted in a suppression of elicitation of cutaneous DTH, as measured by ear swelling. In contrast, pretreatment with anti-dinitrophenyl IgE antibody did not interfere with intestinal inflammation to T. spiralis nor with DTH to PCl. Our results suggest that similar to cutaneous DTH, T. spiralis-specific T-cell factors are involved in the initiation and regulation of the DTH-like mast cell and eosinophil-rich intestinal inflammation that accompanies T. spiralis infections in the gut. Since both Tric-F and PCl-F induce suppression of cellular immune responses in vivo, independent of antigen specificity, it is concluded that Tric-F belongs to the same isotype of TABMs as PCl-F that therefore can be regulated by a non-antigen-specific, isotype-like, T-cell-dependent feedback mechanism.
Phys.Rev. C61 (2000) 014601 Using data obtained through simultaneous measurements of (p,p') spin-transfer
observables and (p,p'gamma) coincident spin observables, we have made a
model-independent ...determination of the complete scattering amplitude for the
15.11 MeV, 1+, T=1 state in 12C at an incident proton energy of 200 MeV, for
four center of mass proton scattering angles ranging from 5.5 to 16.5 degrees.
At each angle, 16 different observables were determined, whereas only 11
independent quantities are required to specify the transition amplitude for
this state. It had been shown previously that the set of observables measured
span the allowed space; hence the system is overdetermined, which allowed us to
extract, in a model-independent fashion, each of the individual spin-operator
amplitudes that characterize the reaction. Additional insight into the physical
mechanisms that drive this transition is obtained by mapping out the
momentum-transfer dependence of these amplitudes. We also compare the
magnitudes and phases determined for each of the spin-operator amplitudes to
the predictions of calculations performed in both relativistic and
nonrelativistic frameworks, and discuss the physics content of these
comparisons.
A histological and behavioral study was used to assess whether acrylamide produced neurotoxic effects in rainbow trout. Swimming performance of trout exposed to 0, 12.5, or 25 mg/liter acrylamide for ...15 days was unaffected. Swimming performance of animals exposed to 50 mg/liter acrylamide for a similar time period was compromised by morbidity and mortality of the animals in this treatment group. The absence of dose-related histological lesions in central neurons, peripheral neurons or muscle suggested that the observed deficit in swimming performance was due to a generalized toxic response. Acrylamide treatment produced dose-related lesions in the gill and liver of rainbow trout.
Accidental ingestion comments received from May 1986 to April 1988 via a toll-free telephone line on detergent product labels were profiled to learn the weight of ingesters, the reported ingestion ...volumes, and the symptoms reported for several different detergent product categories. Most of the ingesters weighed 20 kg or less; however, 10% of the ingesters weighed 70 kg or more. Most detergent product ingestions involved 1 teaspoon of product or less. Reported symptoms varied with product type and ingestion volume.
Using data obtained through simultaneous measurements of (p,p') spin-transfer observables and (p,p'gamma) coincident spin observables, we have made a model-independent determination of the complete ...scattering amplitude for the 15.11 MeV, 1+, T=1 state in 12C at an incident proton energy of 200 MeV, for four center of mass proton scattering angles ranging from 5.5 to 16.5 degrees. At each angle, 16 different observables were determined, whereas only 11 independent quantities are required to specify the transition amplitude for this state. It had been shown previously that the set of observables measured span the allowed space; hence the system is overdetermined, which allowed us to extract, in a model-independent fashion, each of the individual spin-operator amplitudes that characterize the reaction. Additional insight into the physical mechanisms that drive this transition is obtained by mapping out the momentum-transfer dependence of these amplitudes. We also compare the magnitudes and phases determined for each of the spin-operator amplitudes to the predictions of calculations performed in both relativistic and nonrelativistic frameworks, and discuss the physics content of these comparisons.
PDF
