Effects of atmospheric CO2 on photosynthetic characteristics of soybean leaves

Soybean (Glycine max. cv. McCall) plants were grown at 500, 1000, and 2000 umol mol (exp -1) CO2 for 35 days with a photosynthetic photon flux of 300 umol m (exp -2) s (-1). Individual leaves were exposed to step changes of photosynthetic photon flux to study CO2 assimilation rates (CAR), i.e., leaf net photosynthesis. In general, CAR increased when CO2 increased from 500 to 1000 umol mol (exp -1), but not from 1000 to 2000 umol mol (exp -1). Regardless of the CO2 level, all leaves showed similar CAR at similar CO2 and PPF. This observation contrasts with reports that plants tend to become 'lazy' at elevated CO2 levels over time. Although leaf stomatal conductance (to water vapor) showed diurnal rhythms entrained to the photoperiod, leaf CAR did not show these rhythms and remained constant across the light period, indicating that stomatal conductance had little effect on CAR. Such measurements suggest that short-term changes in CO2 exchange dynamics for a controlled ecological life support system can be closely predicted for an actively growing soybean crop

Discrete emotion-congruent false memories in the DRM paradigm

Research has shown that false memory production is enhanced for material that is emotionally congruent with the mood of the participant at the time of encoding. So far this research has only examined the influence of generic negative affective mood states and generic negative stimuli on false memory production. In addition, much of the research is limited as it focuses on valence and arousal dimensions, and fails to take into account the more comprehensive nature of emotions. The current study demonstrates that this effect goes beyond general negative or positive moods and acts at a more discrete emotional level. Participants underwent a standard emotion induction procedure before listening to negative emotional or neutral associative word lists. The emotions induced, negative word lists and associated non-presented critical lures, were related to either fear or anger, two negative valence emotions that are also both high in arousal. Results showed that when valence and arousal are controlled for, false memories are more likely to be produced for discrete emotionally congruent compared to incongruent materials. These results support spreading activation theories of false remembering and add to our understanding of the adaptive nature of false memory production

Negative mood state impairs false memory priming when problem-solving

The aim of this study was to investigate the effect of emotional mood states on the ability to create effective primes using the recently developed false memory priming paradigm. A negative or positive mood state was induced before Deese/Roediger-McDermott (DRM) list presentation. A further control group experienced no mood induction. Participants were then presented with Compound Remote Associate Task (CRAT) problems, half of which had been primed by the previous DRM lists whose critical lure was the solution to the CRAT problem. The results of this study showed that induction of a negative mood state not only impaired recall of critical lures but also diminished their effectiveness as primes for solving CRAT problems. In contrast, for both positive mood and control conditions, the false memory priming advantage was evident, with a higher proportion of primed problems solved in comparison to those not primed. Findings are discussed in relation to the role of affect on semantic activation and the adaptive consequences of false memories

Test-Induced Priming Impairs Source Monitoring Accuracy in the DRM Procedure

Three experiments investigated the effects of test-induced priming (TIP) on false recognition in the Deese/Roediger-McDermott procedure. In Experiment 1, TIP significantly increased false recognition for participants who made old/new decisions at test but not for participants who made remember/know judgements or were given diagnostic information to help them avoid false recognition. In Experiment 2, a TIP effect was observed with old/new recognition but not when participants were required to remember whether study items were spoken by a male or a female. In Experiment 3, false recognition increased when critical lures were preceded by ten studied items but not when preceded by five studied and five unstudied items from the same list. These findings suggest that TIP increases false recognition by disrupting source monitoring processes

Estimation of linkage disequilibrium in a sample of the United Kingdom dairy cattle population using unphased genotypes

The association between genetic marker alleles was estimated for two regions of the bovine genome from a random sample of 50 young dairy bulls born in the United Kingdom between 1988 and 1995. Microsatellite marker genotypes were obtained for six markers on chromosome 2 and seven markers on chromosome 6, spanning 38 and 20 cM, respectively. Two different methods, which do not require family information, were used to estimate population haplotype frequencies. Haplotype frequencies were estimated for pairs of loci using the expectation-maximization algorithm and for all linked loci using a Bayesian approach via a Markov chain-Monte Carlo algorithm. Significant (P = 0.0007) linkage disequilibrium was detected between pairs of loci in syntenic groups (that is, loci in the same linkage group), extending to about 10 cM. No significant linkage disequilibrium was detected between markers in nonsyntenic regions. Given the observed level of linkage disequilibrium, mapping methods based on population-wide association might provide a better resolution than traditional quantitative trait loci mapping methods in the U.K. dairy cattle population and may reduce the required sample sizes of the experiments

The role of attention in immediate emotional false memory enhancement

Two experiments examined the effect of reduced attentional resources on false memory production for emotionally valenced stimuli using the Deese/Roediger-McDermott (DRM) paradigm. Prior research has demonstrated that emotional information is often better remembered than neutral information and that enhanced memory for emotional information is dependent on either automatic or controlled neural processing (Kensinger & Corkin, 2004). Behavioral studies designed to reduce attention resources at encoding have supported neuroimaging findings that indicate high arousal negative stimuli rely more on automatic processing but positive high arousal stimuli rely more on controlled processing. No study has yet examined the attentional resources required to produce emotionally valenced false memories. In Experiment 1, negative, positive, and neutral DRM lists were studied under full or divided attention (DA) conditions, and in Experiment 2, negative and neutral DRM lists were studied under fast (20 ms) or slow (2,000 ms) presentation conditions. Under DA and speeded presentation conditions, higher false memory recognition rates were found for negative compared with positive (Experiment 1) and neutral (Experiments 1 and 2) critical lures. This is the first demonstration of which we are aware that suggests negative false memories are associated with automatic neural processing, whereas positive and nonvalenced neutral false memories are associated with more controlled processing

Susceptibility of Commercial-Off-The-Shelf Sensors to IEMI using Pulse Modulated Signals

The use of sensors has grown dramatically in recent years and many devices rely on the information they provide. The lack of proper security mechanisms available to control the use of sensors and the high degree of integration make them more vulnerable to Intentional Electromagnetic Interference (IEMI). The aim of this paper was to investigate the impact of IEMI on separate sensors with privileged access to the hardware and software to pursue a deep analysis of the effects of IEMI attacks using pulse modulated signals. Measurements were carried out in a shielded hall using an open TEM (Transverse Electromagnetic) waveguide in the 100 MHz–7.5 GHz frequency range. A variety of effects were observed and significant differences were found with pulse modulated signals compared to continuous wave signals. These results indicate weak points in the sensors hardware leading to possible hardening measures.</p

A temporal and spatial study of invertebrate communities associated with hard-bottom habitats in the South Atlantic Bight

Species composition, biomass, density, and diversity of benthic invertebrates from six bard-bottom areas were evaluated. Seasonal collections using a dredge, trawl, and suction and grab samplers yielded 432, 525, and 845 taxa, respectively. Based on collections wltb the different gear types, species composition of invertebrates was found to change bathymetrically. Inner- and mlddle-shelf sites were more similar to each other in terms of invertebrate species composition than they were to outer-shelf sites, regardless of season. Sites on the inner and outer shelf were grouped according to latitude; however, results suggest that depth is apparently a more important determinant of invertebrate species composition than either season or latitude. Sponges generally dominated dredge and trawl collections in terms of biomass. Generally, cnidarians, bryozoans, and sponges dominated at sites In terms of number of taxa collected. The most abundant smaller macrofauna collected in suction and grab samples were polychaetes, amphipods, and mollusks. Densities of the numerically dominant species changed botb seasonally and bathymetrically, with very few of these species restricted to a specific bathymetrlc zone. The high diversity of invertebrates from hard-bottom sites is attributed to the large number of rare species. No consistent seasonal changes in diversity or number of species were noted for individual stations or depth zones. In addition, H and its components showed no definite patterns related to depth or latitude. However, more species were collected at middle-shelf sites than at inner- or outer-shelf sites, which may be related to more stable bottom temperature or greater habitat complexity in that area. (PDF file contains 110 pages.

System development and early biological tests in NASA's biomass production chamber

The Biomass Production Chamber at Kennedy Space Center was constructed to conduct large scale plant growth studies for NASA's CELSS program. Over the past four years, physical systems and computer control software have been continually upgraded and the degree of atmospheric leakage from the chamber has decreased from about 40 to 5 percent of the total volume per day. Early tests conducted with a limited degree of closure showed that total crop (wheat) growth from the best trays was within 80 percent of reported optimal yields for similar light levels. Yields from subsequent tests under more tightly closed conditions have not been as good--up to only 65 percent of optimal yields. Yields appear to have decreased with increasing closure, yet potential problems exist in cultural techniques and further studies are warranted. With the ability to tightly seal the chamber, quantitative data were gathered on CO2 and water exchange rates. Results showed that stand photosynthesis and transpiration reached a peak near 25 days after planting, soon after full vegetative ground cover was established. In the final phase of testing when atmospheric closure was the highest, ethylene gas levels in the chamber rose from about 10 to nearly 120 ppb. Evidence suggests that the ethylene originated from the wheat plants themselves and may have caused an epinastic rolling of the leaves, but no apparent detrimental effects on whole plant function

Response of selected plant and insect species to simulated solid rocket exhaust mixtures and to exhaust components from solid rocket fuels

The effects of solid rocket fuel (SRF) exhaust on selected plant and and insect species in the Merritt Island, Florida area was investigated in order to determine if the exhaust clouds generated by shuttle launches would adversely affect the native, plants of the Merritt Island Wildlife Refuge, the citrus production, or the beekeeping industry of the island. Conditions were simulated in greenhouse exposure chambers and field chambers constructed to model the ideal continuous stirred tank reactor. A plant exposure system was developed for dispensing and monitoring the two major chemicals in SRF exhaust, HCl and Al203, and for dispensing and monitoring SRF exhaust (controlled fuel burns). Plants native to Merritt Island, Florida were grown and used as test species. Dose-response relationships were determined for short term exposure of selected plant species to HCl, Al203, and mixtures of the two to SRF exhaust