High-repetition-rate combustion thermometry with two-line atomic fluorescence excited by diode lasers

We report on kilohertz-repetition-rate flame temperature measurements performed using blue diode lasers. Two-line atomic fluorescence was performed by using diode lasers emitting at around 410 and 451 nm to probe seeded atomic indium. At a repetition rate of 3.5 kHz our technique offers a precision of 1.5% at 2000 K in laminar methane/air flames. The spatial resolution is better than 150 mu m, while the setup is compact and easy to operate, at much lower cost than alternative techniques. By modeling the spectral overlap between the locked laser and the probed indium lines we avoid the need for any calibration of the measurements. We demonstrate the capability of the technique for time-resolved measurements in an acoustically perturbed flame. The technique is applicable in flames with a wide range of compositions including sooting flames

Regional Human Rights Regimes: A Comparison and Appraisal

For Americans at least, active concern for human rights on the international plane is demonstrated perhaps most conspicuously in the promotion and protection of human rights through the United Nations and its allied agencies--apart, that is, from the promotion and protection of human rights through United States foreign policy and the work of such nongovernmental organizations as Amnesty International. Supplementing this globally-oriented human rights activity, however, are international human rights regimes operating regionally in Western Europe, the Americas, Africa and the Middle East. Concededly, Asia is not yet represented, and only the first three of the represented regions have gone so far as to create enforcement mechanisms within the framework of a human rights charter, as evidenced by the European Convention for the Protection of Human Rights and Fundamental Freedoms and the European Social Charter, the American Convention on Human Rights and the Banjul (African) Charter on Human and Peoples\u27 Rights. The Permanent Arab Commission on Human Rights, founded by the Council of the League of Arab States in September 1968 but since then understandably preoccupied by the rights of Palestinian Arabs in and to the Israeli-occupied territories, has yet to bring a proposed Arab Convention on Human Rights to successful conclusion, and so far has tended to function more in terms of the promotion than the protection of human rights. Nevertheless, the regional development of human rights norms, institutions and procedures is likely to grow. Already an important dynamic of international human rights law and policy, it is, in any event, here to stay

Neural Circuit Recording from an Intact Cockroach Nervous System

The cockroach ventral nerve cord preparation is a tractable system for neuroethology experiments, neural network modeling, and testing the physiological effects of insecticides. This article describes the scope of cockroach sensory modalities that can be used to assay how an insect nervous system responds to environmental perturbations. Emphasis here is on the escape behavior mediated by cerci to giant fiber transmission in Periplaneta americana. This in situ preparation requires only moderate dissecting skill and electrophysiological expertise to generate reproducible recordings of neuronal activity. Peptides or other chemical reagents can then be applied directly to the nervous system in solution with the physiological saline. Insecticides could also be administered prior to dissection and the escape circuit can serve as a proxy for the excitable state of the central nervous system. In this context the assays described herein would also be useful to researchers interested in limb regeneration and the evolution of nervous system development for which P. americana is an established model organism

The cluster Abell 780: an optical view

The Abell 780 cluster, better known as the Hydra A cluster, has been thouroughly analyzed in X-rays. However, little is known on its optical properties. We derive the galaxy luminosity function (GLF) in this apparently relaxed cluster, and search for possible environmental effects by comparing the GLFs in various regions, and by looking at the galaxy distribution at large scale around Abell 780. Our study is based on optical images obtained with the ESO 2.2m telescope and WFI camera in the B and R bands, covering a total region of 67.22x32.94 arcmin^2, or 4.235x2.075 Mpc^2 for a cluster redshift of 0.0539. In a region of 500 kpc radius around the cluster centre, the GLF in the R band shows a double structure, with a broad and flat bright part and a flat faint end that can be fit by a power law with an index alpha=-0.85+-0.12 in the 20.25<R<21.75 interval. If we divide this 500 kpc radius region in North+South or East+West halves, we find no clear difference between the GLFs in these smaller regions. No obvious large scale structure is apparent within 5 Mpc from the cluster, based on galaxy redshifts and magnitudes collected from the NED database in a much larger region than that covered by our data, suggesting that there is no major infall of material in any preferential direction. However, the Serna-Gerbal method reveals the presence of a gravitationally bound structure of 27 galaxies, which includes the cD, and of a more strongly gravitationally bound structure of 14 galaxies. These optical results agree with the overall relaxed structure of Abell 780 previously derived from X-ray analyses.Comment: Accepted for publication in Astronomy & Astrophysic

Reproductive Biology of Cobia, Rachycentron canadum, from Coastal Waters of the Southern United States

Reproductive biology of the cobia, Rachycentron canadum, is described from four coastal areas in the southern United States. Samples were obtained from recreational fishermen between December 1995 and November 1997 from the southeastern United States (Morehead City, NC, to Cape Canaveral, FL), the eastern Gulf of Mexico (Ft. Myers to Crystal River, FL), the north-central Gulf of Mexico (Destin, FL, to Chandeleur Islands, LA) and the western Gulf of Mexico (Port Aransas, TX). Histological evidence of spawning occurred from April through September in all areas. Some female cobia (17-32%) throughout the Gulf of Mexico had spent or regressed ovaries by July. Gonadosomatic index peaked between May and July throughout the region. Ovaries of females from all areas contained both postovulatory follicles (POF) and oocytes in final oocyte maturation (FOM) during all months of the reproductive season. Batch fecundity was calculated by using three different methods: oocytes \u3e700 pm were fixed in 1) Gilson\u27s fixative or 2) 10% neutral buffered formalin (NBF), and 3)oocytes undergoing FOM were sectioned for histological examination. Mean batch fecundity ranged from 377,000 +/- 64,500 to 1,980,500 +/- 1,598,500 eggs; there was no significant difference among methods. Batch fecundity calculated with the NBF method showed a positive relationship with fork length (P=0.021, r(2)=0.132) and ovary-free body weight (OFBW; P=0.016, r(2)=0.143). Relative batch fecundity was not significantly different among months during the spawning season and averaged 53.1 +/-9.4 eggs/g OFBW for the NBF method and 29.1 +/- 4.8 eggs/g OFBW for the FOM method. Although spawning frequencies were not significantly differ ent among areas (P=0.07), cobia from the southeastern United States and north-central Gulf of Mexico were estimated to spawn once every 5 days, whereas cobia from the western Gulf of Mexico were estimated to spawn once every 9 to 12 days

Reproductive Biology of Cobia, \u3ci\u3eRachycentron canadum\u3c/i\u3e, from Coastal Waters of the Southern United States

Reproductive biology of the cobia, Rachycentron canadum, is described from four coastal areas in the southern United States. Samples were obtained from recreational fishermen between December 1995 and November 1997 from the southeastern United States (Morehead City, NC, to Cape Canaveral, FL), the eastern Gulf of Mexico (Ft. Myers to Crystal River, FL), the north-central Gulf of Mexico (Destin, FL, to Chandeleur Islands, LA) and the western Gulf of Mexico (Port Aransas, TX). Histological evidence of spawning occurred from April through September in all areas. Some female cobia (17-32%) throughout the Gulf of Mexico had spent or regressed ovaries by July. Gonadosomatic index peaked between May and July throughout the region. Ovaries of females from all areas contained both postovulatory follicles (POF) and oocytes in final oocyte maturation (FOM) during all months of the reproductive season. Batch fecundity was calculated by using three different methods: oocytes \u3e700 μm were fixed in 1) Gilson’s fixative or 2) 10% neutral buffered formalin (NBF), and 3) oocytes undergoing FOM were sectioned for histological examination. Mean batch fecundity ranged from 377,000 ± 64,500 to 1,980,500 ± 1,598,500 eggs; there was no significant difference among methods. Batch fecundity calculated with the NBF method showed a positive relationship with fork length (P = 0.021, r2 = 0.132) and ovary-free body weight (OFBW; P = 0.016, r2 = 0.143). Relative batch fecundity was not significantly different among months during the spawning season and averaged 53.1 ± 9.4 eggs/g OFBW for the NBF method and 29.1 ± 4.8 eggs/g OFBW for the FOM method. Although spawning frequencies were not significantly different among areas (P = 0.07), cobia from the southeastern United States and north-central Gulf of Mexico were estimated to spawn once every 5 days, whereas cobia from the western Gulf of Mexico were estimated to spawn once every 9 to 12 days