Is male back space limiting? An investigation into the reproductive demography of the giant water bug,Abedus indentatus (Heteroptera: Belostomatidae)

Because male giant water bugs in the subfamily Belostomatinae provide parental care by brooding eggs on their back, an accurate assessment can be made of both the actual and potential reproductive capacity of males. Two operational sex-ratio (OSR) indices were developed and empirically measured for a population of giant water bug, Abedus indentatus,in California. One index was based on reproductive rates measured in the laboratory; the other index was based on reproductive resources observed in the field. Both OSR indices suggest that the operational sex ratio fluctuates between maleskewed ratios in the summer and femaleskewed ratios in the winter. This pattern appears to be the consequence of two factors. First, the adult sex ratio is significantly female biased. Second, although males can outreproduce females at high ambient temperatures, the reverse is true at low temperatures. Possible reasons for the female-skewed adult sex ratio are examined, including differential recruitment, differential mortality, and sampling bias.     

Ectonucleotidase Activities Associated with the Olfactory Organ of the Spiny Lobster

The olfactory system of the Florida spiny lobster, Panulirus argus, has olfactory receptors that are excited by the purine nucleotides AMP, ADP, and ATP. These receptors reside on chemosensory neurons that are contained within aesthetasc sensilla on the lateral filaments of the antennules. Also associated with the lobster's olfactory system are ectonucleotidase activities that dephosphorylate excitatory nucleotides, resulting in the production of the nonstimulatory nucleoside adenosine. Our studies of the 5'-ectonucleotidase, ecto-ADPase, and ecto-ATPase activities of this olfactory system showed that each activity was characterized by Michaelis-Menten kinetics; Michaelis constants ranged from 6.9 to 33.5 microM, and maximum velocities ranged from 2.5 to 28.8 fmol/sensillum/s. Evidence that AMP dephosphorylation may serve as an inactivation process was shown by the close correlation between the kinetics of 5'-ectonucleotidase activity and the periodicity of olfactory sampling. Decreased magnesium ion concentration or increased calcium ion concentration resulted in increased ecto-ATPase activity; this activity was insensitive to vanadate ion. Ectonucleotidase activities may have multiple effects on the detection of exogenous nucleotides by a chemosensory system. These effects can be either direct, such as the conversion of an odorant to an inactive compound, or indirect, such as the conversion of an odorant to another compound that can activate or inhibit either receptors or enzymes associated with the system.     

Comparability of two tests of olfactory functioning

In the first of two comparisons, 50 patients who came to theConnecticut Chemosensory Clinical Research Center (CCCRC) withvarious chemosensory complaints were evaluated by a dual threshold/odoridentification test administered in the CCCRC and by the self-administeredUniversity of Pennsylvania Smell Identification Test (UPSIT).Agreement between tests proved high, with a correlation coefficientof 0.92. The UPSIT correlated better with the odor identificationcomponent than with the threshold component of the CCCRC test.This disparity stemmed largely from limitations in the reliabilityof the threshold component. An increase in the stringency ofthe criterion for determination of threshold increased the reliabilityof this component and, in a second comparison with a total of58 patients and controls, the correlation between the UPSITand CCCRC test increased. With the more stringent criterion,the correlation equalled 0.96. ²Present address: International Flavors and Fragrances, Researchand Development, Union Beach, NJ 07735, USA     

A sensitive and rapid luminescence sandwich assay for antibodies to hepatitis-B surface antigen (Anti-HBsAg)

A chemiluminescent assay for hepatitis-B surface antigen is described which used an isoluminol derivative as the label. The assay is precise intra-assay CV, 1.96-2.45%; inter-assay CV, 5.26-8.11% and has a lower detection limit for hepatitis-B surface antigen of 1.3U/I.     

Genomic complexity and plasticity of Burkholderia cepacia

Abstract Burkholderia cepacia has attracted attention because of its extraordinary degradative abilities and its potential as a pathogen for plants and for humans. This bacterium was formerly considered to belong to the genus Pseudomonas in the γ-subclass of the Proteobacteria , but recently has been assigned to the β-subclass based on rrn gene sequence analyses and other key phenotypic characteristics. The B. cepacia genome is comprised of multiple chromosomes and is rich in insertion sequences. These two features may have played a key role in the evolution of novel degradative functions and the unusual adaptability of this bacterium.     

Switch and Bait: Probing the Discriminative Basis of Odor Identification via Recognition Memory

When people misidentify everyday odors, as they often do, theirerrors may conceivably lie in faulty perceptions or in faultyaccess to the names. Discussions of the matter usually focuson the latter, as if people had no problems with perceptualaccuracy. (The problem of faulty access may get attention becauseits high subjective impact makes it particularly memorable,when it does occur.) However, studies have demonstrated breakdownsin ability to discriminate quality, from which it follows thatpeople will misidentify items through perceptual confusions.Furthermore, misidentifications often contain considerable informationabout the identities of items, as if people simply did not perceivethe items accurately, but perhaps fuzzily or with some perceptualbias. Recognition memory, with a 2-day interval between inspectionand test, provided a vehicle to address two questions on thistopic: (i) Would people notice that we had switched items andhad presented for recognition items that matched their misidentificationsrather than the original items inspected? (ii) Would peoplenot only fall for the false bait, but actually identify theswitched items correctly, and thereby imply that they were ‘tuned’to perceive those odors? People commonly failed to notice theswitches, i.e. took the bait and commonly identified the switcheditems with veridical names. Although subject to further study,the outcome suggests that when people give such names as garlicfor vinegar, orange for lime, soy sauce for molasses and manyothers, the errors often lie largely at a perceptual stage ofprocessing, i.e. at input rather than output. Chem. Senses 21:35–44, 1996.     

Suffering, justice, and the politics of becoming

To suffer is to undergo, to bear, to endure. Suffering exists on the underside of agency; it is as important to ethics as agency. The experience of suffering is never entirely captured by the ethical, political, medical and spiritual categories in which it is represented. Perhaps an engagement with suffering can open up hidden connections between these domains. After examining John Caputo and Friedrich Nietzsche comparatively on the relation between suffering and ethics, this essay explores the relation of the politics of becoming to suffering. The politics of becoming is a paradoxical process by which a new cultural identity is drawn into being and yet is irreducible to the energies and motives that spurred its initiators to action. To exemplify and think the politics of becoming is to call into question the sufficiency of existing paradigms of morality. A critical examination of the Rawlsian model of justice brings out, for example, the insufficiency of justice to the politics of becoming. It suggests the need, first, to pursue an ethics of engagement between several parties drawing upon a variety of sources of ethical inspiration and, second, to cultivate ldcritical responsiveness to new social movements that struggle to place new identities onto the cultural register. If the latter movements sometimes modify general understandings of suffering, identity, justice and medical practice they also indicate the role cultural thinkers can play in re-examining periodically established codes of interaction between these domains.A paper presented, with commentaries, as the 1995 Roger Allan Moore Lecture at Harvard Medical School, Center for the Study of Culture and Medicine, May 11, 1995.