Perceptual outcomes as reinforcers

The paucity of basic behavioral research with humans was highlighted almost 40 years ago (Findley, 1966). A recent search of the basic behavioral research journals by the present authors indicated that this situation remains, with only approximately 15% of the research using human participants. It may seem surprising that so few studies use human participants given the apparent practical advantages of doing so. Human participants are readily available, extensively pre-trained, can use a range of complex apparatus and require no feeding or housing. In reality, however, the use of human participants involves a number of practical difficulties: humans generally will not agree to participate in research involving a large number of sessions or sessions lasting more than two to three hours; it is difficult to gain within-session compliance as a result of the often repetitive and simplistic nature of the tasks; and it is often unclear whether the experimental results are a product of the experimentally-arranged contingencies or the instructions given to the participants. Another difficulty, that which is addressed here, lies in the identification of a suitable experimental outcome that will serve as a reinforcer

Precision teaching and fluency: the effects of charting and goal-setting on skaters’ performance

This research involved three successive studies where precision teaching methods were used to increase roller skaters performance rates of basic skating skills. The first study compared precision teaching methods both with and without the use of charting in a group design, and compared both within-subject and betweensubject differences for 12 skaters. Results showed that charting did not increase performance rates over that seen when charting was not used. The second study was a group design which compared two different types of goals, or performance aims, on skaters‟ performance. No difference was found between the two groups of 5 skaters when one group used a fixed, difficult goal and a second used a flexible, easier goal. In the final study, a single-subject design was used and 8 skaters completed a control condition where no goals were set before a goal was introduced for 4 skaters. It was found that an immediate increase in performance rates occurred following the introduction of the goal. Overall these three studies showed that skaters improved their performance rates over sessions, even in the absence of charting and/or goals, demonstrating that precision teaching can be applied to the sport of roller skating

Extinction-induced variability in human behavior

Participants earned points by pressing a computer space bar (Experiment 1) or forming rectangles on the screen with the mouse (Experiment 2) under differential-reinforcement-of-low-rate schedules, followed by extinction. Variability in interresponse time (the contingent dimension) increased during extinction, as for Morgan and Lee (1996); variability in diagonal length (the noncontingent dimension, Experiment 2) did not. In Experiment 3, points were contingent on rectangle size. Rectangle size and interresponse-time (the noncontingent dimension) variability increased in extinction. There was greater variability in the contingent dimension during extinction for participants with the more varied history of reinforcement in Experiment 2 but not in Experiment 3. Overall, variability in the contingent dimension increased in extinction, but the degree of increase was affected by reinforcement history

Macroecology of parental care in arthropods: higher mortality risk leads to higher benefits of offspring protection in tropical climates

The intensity of biotic interactions varies around the world, in such a way that mortality risk imposed by natural enemies is usually higher in the tropics. A major role of offspring attendance is protection against natural enemies, so the benefits of this behaviour should be higher in tropical regions. We tested this macroecological prediction with a meta-regression of field experiments in which the mortality of guarded and unguarded broods was compared in arthropods. Mortality of unguarded broods was higher, and parental care was more beneficial, in warmer, less seasonal environments. Moreover, in these same environments, additional lines of defence further reduced offspring mortality, implying that offspring attendance alone is not enough to deter natural enemies in tropical regions. These results help to explain the high frequency of parental care among tropical species and how biotic interactions influence the occurrence of parental care over large geographic scales. Finally, our findings reveal that additional lines of defences – an oftentimes neglected component of parental care – have an important effect on the covariation between the benefits of parental care and the climate-mediated mortality risk imposed by natural enemies

Relationship between precooling, storage temperature and storage duration to the quality characteristics of guava (Psidium guajava cv. Kampuchea)

The effects of cooling time, storage temperature and storage duration on the guava cv. Kampuchea were determined. The experimental design carried out was RCBD with a factorial arrangement of treatments (4 cooling times x 3 storage temperatures x 6 duration of storage) and three replications with two fruits per each replication. The results indicated that cooling time only effected the browning but it did not significantly effect the visual appearance, skin colour, weight loss and soluble solids concentration. Treatment combinations of storage temperature and storage duration were found to have significant effects on the visual appearance, skin colour, weight loss and soluble solids concentration. However, the treatment did not significantly effect browning. Storage temperature of 10°C resulted slow loss of visual appearance, delayed changes on the skin colour, lowest weight loss, and the lowest changes in soluble solids concentration of fruit. Acceptable visual appearance of the fruit stored at 10°C was up to 3.6 weeks compared to only 1.6 and 1.3 weeks for the fruit stored at 5 and 15oC, respectively. The limit of acceptable L*, C* and ho changes in this study were 65.33 +3.3, 43.0 +0.5 and 113.83 +2.5, respectively and this colour space values corresponded to pale green fruit. In addition, the fruit stored at 10°C were found to have lowest incident of browning compared to those stored at 5°C, while the fruit stored at 15°C were ripened, developed senescence, shrivelled and freckled. Results of this research can be used by guava producers in deciding the time level for their precooling and temperature setting for their cold room

The effects of Catharanthus roseus (l) g. don 1838 aqueous leaf extract on some liver enzymes, serum proteins and vital organs

Plant and phytochemical products continue to play an important role in medicine. In this study, the toxicological potentials of the aqueous leaf extract of Catharanthus roseus G. Don 1838 in rabbits were determined. The rabbits were placed in three groups with four rabbits in each group. The control group, a second group administered with 100mg/Kg and third group administer with 360mg/Kg body weight, were tag as Group 1, 2 and 3 respectively. Increased levels of serum alanine transaminase (ALT), aspartate transaminase (AST) and alkaline phosphatase (ALP) were found to follow the treatment of rabbits with ACR suggesting liver damage. This was confirmed by the histopathological studies that reveal centrieolobular hemorrhagic necrosis of the liver. Also, there was oxidative glomerulonephritis that set in. The effect of the extract in the activity of the hepatocellular enzymes (ALT, AST, and ALP) was found to be concentration dependent. This suggest that the infusion of the leaves could cause hepatocellular damage and kidney impairment. Keywords: Catharanthus roseus, Aqueous Leaf extract, Toxicity, Alkaloids, Enzymes levels

In vitro Inhibitory Studies and Effect of Selected Plant Extracts and Cations on Elastase (EC 3.4.21.11) Activity produced by Aspergillus niger and Aspergillus flavus

Elastase is a member of the serine protease enzyme family that hydrolytically degrades elastin, a connective tissue component leading to aging and wrinkling of the skin. In this report, we investigated the in-vitro inhibitory effects of some cations and n-hexane extract of Hibiscus cannabinus, Vernonia amygdalina, Murraya koenigii, and Telfairia occidentalis on the activity of Elastase isolated from Aspergillus flavus and Aspergillus niger. Elastase was extracted, isolated and partially purified from Aspergillus flavus and Aspergillus niger. The data obtained in this study demonstrated that the activity of elastase in Aspergillus flavus was higher compared to that of Aspergillus niger after salting out. The elastase inhibition activities of Hibiscus cannabinus, Vernonia amygdalina, Murraya koenigii, and Telfairia occidentalis reveal that the leaf extract from Murraya koenigii, in Aspergillus flavus had more significant inhibition was obtained compared to that of Aspergillus niger, with inhibitory effect from 40µg/ml. While that of Hibiscus cannabinus showed similar inhibition characteristics to Murraya koenigii. Both Hibiscus cannabinus and Vernonia amygdalina had an effect at 80µg/ml; all the extracts appeared to have more effects on the enzyme obtained from Aspergillus flavus than from the Aspergillus niger. The potential of exploring these plant extract as an anti-aging recipe was discussed. Keywords: Inhibitory studies, Elastase, Aspergillus flavus, Aspergillus niger, Hibiscus cannabinus, Vernonia amygdalina, Murraya koenigii, and Telfairia occidentali

Anti-diabetic Properties and Phytochemical Studies of Ethanolic Leaf Extracts of Murraya Koenigii and Telfairia Occidentalis on Alloxan-Induced Diabetic Albino Rats

The antidiabetic properties and phytochemical studies of fractions of ethanolic leaf extract (400mg/Kgb.w) of Murraya koenigii (M. koenigii) and Telfairia occidentalis (T. occidentalis) was carried out on alloxan induced diabetic albino rats. Four and three fractions were obtained from M. koenigii and T. occidentalis extract respectively using column chromatography. Phytochemical screening of each fraction, indicate the presence of saponins, alkaloids, flavonoids, tannins and cardiac glycosides. The alloxan induced diabetic rats were treated with fractions of the extract, and fraction 1 and 2 of M. koenigii and T. occidentalis respectively which decreased blood glucose level significantly (p<0.05) by 72% and 78% respectively when compared within the group and showed no significant different when compared to normal control group. All treated groups showed no significant changes (p<0.05) in their body weight with the exception of groups treated with 3rd fractions of M. koenigii and T. occidentalis. Spectroscopic studies indicated the presence of  biological active compound in the 1st, 2nd and 3rd fractions of M. koenigii that absorbed maximally at 200-350nm and the 4th fraction showed absorption maximally at 270nm and 290nm; while the 1st fraction of T. occidentalis absorbed maximally at 320nm, 2nd fraction at 290nm and 340nm and 3rd fraction at 320nm and 350nm.  The 1st fraction of M. koenigii and 2nd fraction of T. occidentalis showed high antidiabetic properties at  λ max 320nm and 340nm respectively. Our findings certainly suggest among others the use of plants as a source of  potentially useful antidiabetic therapy for diabetics. Keywords: Diabetes mellitus, Antidiabetic components, Telfairia occidentalis and Murraya koenigi

Line Lists Including Intensities for Diatomic Molecules of Astronomical Interest and Remote Sensing Measurements of Greenhouse Gases

Line lists including positions and absolute intensities have been produced using a combination of theoretical and experimental methods, for several spectroscopic systems of diatomic molecules, including the C2 and 12C13C Swan systems, the CN, 13CN, and C15N A2Π-X2Σ+ (red), B2Σ+-X2Σ+ (violet), and X2Σ+ state rovibrational systems, the CP A2Π-X2Σ+ system, and the NH X3Σ− state rovibrational and rotational transitions. Preliminary calculations for the OH X2Π state rovibrational transitions have also been performed. RKR potential energy curves, vibrational wavefunctions, and matrix elements (MEs) were calculated using the programs RKR1 and LEVEL. The MEs were transformed from Hund’s case (b) to (a), for which an equation was derived. Einstein A values were calculated from the case (a) MEs and molecular constants using PGOPHER. These lists will be useful in the fields of astronomy, combustion science, materials science, and anywhere else that transitions of these diatomic molecules are investigated. Line intensities have also been used to retrieve an atmospheric CO2 volume mixing ratio. A new technique for the satellite remote sensing of atmospheric greenhouse gases via absorption of short-wave infrared laser signals transmitted between counter-rotating satellites in low Earth orbit has recently been proposed; this would enable the acquisition of a long-term, stable, global set of altitude-resolved concentration measurements. The first ground-based experimental demonstration of this new infrared-laser occultation method is presented, in which the atmospheric absorption of CO2 near 2.1 µm and CH4 near 2.3 µm were measured over a 144 km path length between two peaks in the Canary Islands, using relatively low power diode lasers. The retrieved CO2 volume mixing ratio of 400 ppm (±15 ppm) is consistent within experimental uncertainty with simultaneously recorded validation measurements. The new method has a sound basis for monitoring atmospheric CO2 and other greenhouse gases

Experimental evidence of bandgap structures in the lower jaw of the bottlenose dolphin (tursiops truncatus)

Previous studies using the TLM numerical modelling technique have demonstrated the potential existence of bandgap structures within the lower jawbone of the Atlantic Bottlenose dolphin (Tursiops truncatus). The study presented here shows experimental evidence of the existence of these bandgaps within a 2-D structure that mimics the prinnciple dimensions of the lower teeth and jawbone of the Bottlenose dolphin. The bandgap present is due to the tooth structure in the lower jaw forming a periodic array of scattering elements, which results in the formation of an acoustic stop band that is angular dependent