Bio-economic evaluation of pasture-cropping, a novel system of integrating perennial pastures and crops on crop-livestock farms

Pasture-cropping is a novel approach to increase the area of perennial crops in mixed sheep and cropping systems. It involves planting annual cereals directly into a living perennial pasture. There is interest in subtropical grasses as they are winter dormant and their growth profile is potentially well suited to pasture-cropping. However, a wide range of factors can affect the uptake of such systems. This paper assesses the relative importance of factors that can influence decisions to introduce pasture-cropping. In this paper the research question is: what factors predispose a farm to take up a new technology such as (1) subtropical grass and (2) subtropical grass that is pasture-cropped. The analysis uses the MIDAS model of a central wheatbelt farm in Western Australia. The results suggest the adoption of subtropical grasses is likely to be strongly influenced by soil mix; feed quality; and whether the farm is predominantly grazing or cropping and by the presence of meat versus wool producing animals. The same factors are relevant for subtropical grass that is pasture-cropped but in addition yield penalties due to competition between the host perennial and the companion cereal become important. The results suggest the level of forage production by subtropical grass is less important but this factor is likely to become more important if feed quality can be improved.Environmental Economics and Policy,

Tropical Transpacific Shore Fishes

Tropical transpacific fishes occur on both sides of the world's largest deep-water barrier to the migration of marine shore organisms, the 4,000- to 7,000-km-wide Eastern Pacific Barrier (EPB). They include 64 epipelagic oceanic species and 126 species of shore fishes known from both the tropical eastern Pacific (TEP) and the central and West Pacific. The broad distributions of 19 of 39 circumglobal transpacific species of shore fishes offer no clues to the origin of their TEP populations; TEP populations of another 19 with disjunct Pacific distributions may represent isthmian relicts that originated from New World populations separated by the closure of the Central American isthmus. Eighty species of transpacific shore fishes likely migrated eastward to the TEP, and 22 species of shore fishes (12 of them isthmian relicts) and one oceanic species likely migrated westward from the TEP. Transpacific species constitute ~12% of the TEP's tropical shore fishes and 15-20% of shore fishes at islands on the western edge of the EPB. Eastward migrants constitute ~7% of the TEP's shore-fish fauna, and a similar proportion of TEP endemics may be derived from recent eastward immigration. Representation of transpacific species in different elements of the TEP fauna relates strongly to adult pelagic dispersal ability-they constitute almost all the epipelagic oceanic species, ~25% of the inshore pelagic species, but only 10% of the demersal shore fishes. Taxa that have multiple pelagic life-history stages are best represented among the transpacific species. Among demersal teleosts that have pelagic larvae, pelagic spawners are better represented than demersal spawners among transpacific species, perhaps because offshore larval development and longer pelagic larval durations provide the former with greater dispersal capabilities. There are strong phylogenetic effects on representation in the transpacific fauna: (1) elasmobranchs are proportionally better represented than teleosts, even teleosts with more pelagic life-history stages; (2) a pelagic juvenile stage with great dispersal potential allows tetraodontiforms that produce demersal or pelagic eggs to be well represented; and (3) various speciose central Pacific families with "adequate" larval dispersal characteristics lack transpacific species. El Niiios potentially enhance eastward migration by increasing eastward flow and halving transit times across the EPB. However, that effect may be offset by low productivity and high temperatures in those eastbound flows. There is little clear evidence of strongly increased migration across the EPB during El Niiios, including recent extreme events (1982-1983 and 1997-1998). During such events shore fishes in the TEP experience range expansions and become locally abundant at marginal areas such as the Galapagos, changes that can be confused with increased migration across the EPB. Although there is a strong bias toward eastward migration among the transpacific shore fishes, there likely is much more westward migration than previously realized: 20-25% of transpacific species may have migrated in that direction. Stronger eastbound than westbound currents can account for this bias. Westward migrants have better developed pelagic dispersal characteristics than many eastward migrants, suggesting that westward migration is more difficult. Many westward migrants associate with flotsam and flotsam-mediated migration is more likely to be westward. All westward migrants occur at Hawai'i, but only about one-fifth of them at the Marquesas. This bias may be due to: Hawai'i being a larger target and in the path of most of the flotsam dispersal from the TEP; an eastward current that impinges on the Marquesas, reducing westward arrivals; and most propagules dispersing toward the tropical Marquesas originating in the temperate eastern Pacific. However, the Hawaiian Islands also are much better sampled than the Marquesas. Although the TEP reef-fish fauna may be depauperate relative to that of the Indo-Malayan "center of diversity," it is as rich as the faunas of islands on the western side of the EPB. Hence a preponderance of eastward migration does not represent a response to a richness gradient across that barrier. There is little evidence that a paucity of ecological groups in the native TEP fauna is primarily responsible for the structure of the eastward-migrant fauna. Rather, eastward migrants may simply represent a cross section of those in the donor fauna, tempered by phylogenetic variation in dispersal ability. Because few central Pacific fishes can live only on live corals and coral reefs, the rarity of such reefs in the TEP is unlikely to strongly limit eastward migration. Differences between oceanic and adjacent continental reef-fish faunas in the West Pacific indicate that each is strongly tied to its respective habitat. Hence, the rarity in the TEP of the (overwhelmingly) most abundant habitat present in the central Pacific-tropical oceanic reefs-may strongly limit migration in both directions across the EPB: there is little suitable habitat for eastward migrants in the TEP and few suitable species and tiny source populations for westward migrants. The global effects that oceanic/continental habitat differences have on reef-fish biogeography need further assessment. Genetic data on ~18% of the transpacific species indicate: that conspecific populations of oceanic species (especially) and shore fishes are genetically well connected across the EPB; that circumtropical taxa in the TEP include isolated isthmian relicts and recent eastward migrants; that all five TEP species of one circumtropical genus (Thalassoma) were derived by several eastward invasions after the closure of the Isthmus of Panama; that some isolated Hawaiian central Pacific populations were established by postisthmian invasion from the TEP; and that Indo-central Pacific species unsuspectedly can co-occur with their endemic sibling sisters in the TEP. Genetic data support distributional data that indicate a strong preponderance of eastward migration across the EPB but also more westward migration than previously thought. Future genetic studies should resolve a question that distributional data cannot: how many widespread presumed eastward-migrant transpacific species actually originated by westward migration from the TEP

NRF2 and the Ambiguous Consequences of Its Activation during Initiation and the Subsequent Stages of Tumourigenesis

NF-E2 p45-related factor 2 (NRF2, encoded in the human by NFE2L2) mediates short-term adaptation to thiol-reactive stressors. In normal cells, activation of NRF2 by a thiol-reactive stressor helps prevent, for a limited period of time, the initiation of cancer by chemical carcinogens through induction of genes encoding drug-metabolising enzymes. However, in many tumour types, NRF2 is permanently upregulated. In such cases, its overexpressed target genes support the promotion and progression of cancer by suppressing oxidative stress, because they constitutively increase the capacity to scavenge reactive oxygen species (ROS), and they support cell proliferation by increasing ribonucleotide synthesis, serine biosynthesis and autophagy. Herein, we describe cancer chemoprevention and the discovery of the essential role played by NRF2 in orchestrating protection against chemical carcinogenesis. We similarly describe the discoveries of somatic mutations in NFE2L2 and the gene encoding the principal NRF2 repressor, Kelch-like ECH-associated protein 1 (KEAP1) along with that encoding a component of the E3 ubiquitin-ligase complex Cullin 3 (CUL3), which result in permanent activation of NRF2, and the recognition that such mutations occur frequently in many types of cancer. Notably, mutations in NFE2L2, KEAP1 and CUL3 that cause persistent upregulation of NRF2 often co-exist with mutations that activate KRAS and the PI3K-PKB/Akt pathway, suggesting NRF2 supports growth of tumours in which KRAS or PKB/Akt are hyperactive. Besides somatic mutations, NRF2 activation in human tumours can occur by other means, such as alternative splicing that results in a NRF2 protein which lacks the KEAP1-binding domain or overexpression of other KEAP1-binding partners that compete with NRF2. Lastly, as NRF2 upregulation is associated with resistance to cancer chemotherapy and radiotherapy, we describe strategies that might be employed to suppress growth and overcome drug resistance in tumours with overactive NRF2

Persistence of cefotetan on red blood cells

Cefotetan can cause severe immune hemolytic anemia that may persist long after the drug is discontinued. To study the binding of cefotetan to RBCs, patients who received cefotetan were followed and tested for the presence of antibody to cefotetan. STUDY DESIGN AND METHODS:  Patients receiving cefotetan were identified from pharmacy and nursing records. Blood samples obtained for routine hematology tests were analyzed. Cefotetan binding to patients’ RBCs was tested using a previously characterized high-titer anticefotetan serum by gel technique. To determine the minimum amount of drug necessary for binding to occur, RBCs were incubated with serial dilutions of cefotetan at pH 7.4. RESULTS:  Sixty patients receiving 1 to 25 g IV (median, 2 g) of cefotetan were followed for 1 to 123 days (median, 18 days). All were initially positive, for cefotetan on RBCs. Positivity persisted for up to 98 days after the last dose of drug. Fifteen patients became negative during follow-up. The first negative sample occurred at Day 30 to 123. Using the midpoint between the last positive and first negative to estimate of the duration of positivity, we estimate that cefotetan remains RBC-bound for 16.5 to 92 days (median, 67.5 days). During the follow-up period, five patients developed anticefotetan detectable in the serum. Twenty patients receiving other cephalosporin antibiotics showed no specific reactivity of their RBCs with anticefotetan. In vitro studies showed a minimum necessary drug concentration of 1 µmol/L at physiologic pH, which was not significantly altered by RBC pretreatment with ficin, sialydase, or DTT. CONCLUSIONS:  Cefotetan is tightly bound to RBCs after intravenous administration and remains detectable for weeks after the last dose. Antibodies to cefotetan may occur in about 8 percent of patients receiving the drug. The minimum necessary concentration for RBC binding is low compared to an estimated plasma concentration of 240 µmol/L from a single IV dose of 1 g.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/72360/1/j.1537-2995.2004.03360.x.pd

Ensembles of AGCM Two-Tier Predictions and Simulations of the Circulation Anomalies during Winter 1997–98

The impact of sea surface temperature (SST) anomalies on the extratropical circulation during the El Niño winter of 1997–98 is studied through atmospheric general circulation model (AGCM) integrations. The model's midlatitude response is found to be very robust, of the correct amplitude, and to have a fairly realistic spatial structure. The sensitivity of the results to different aspects of the anomalous distributions of SST is analyzed. It is found that the extratropical circulation in the North Pacific–North American sector is significantly different if SST anomalies over the Indian Ocean are included. Using a comparison of observed and simulated 200-hPa streamfunction anomalies, it is argued that the modeled midlatitude impact of Indian Ocean SST anomalies is largely realistic. However, while the local sensitivity of the atmosphere to small differences in SST anomalies in the tropical Pacific can be substantial, the remote sensitivity in midlatitudes is small. Consistently, there is little difference between the simulated extratropical circulation anomalies obtained using SSTs predicted by the National Centers for Environmental Prediction in October 1997 and those obtained using observed tropical Pacific SSTs. Neither is there any detectable atmospheric signal associated with SST anomalies over the North Pacific. Analyses of the results presented here suggest that the influence of SST anomalies in the Pacific and Indian Oceans during the selected ENSO event can be interpreted as the quasi-linear superposition of Rossby wave trains emanating from the subtropics of each ocean. An inspection of intraseasonal weather regimes suggests that the influence of tropical SST anomalies can also be described as a shift in the frequency of occurrence of the model's modes of intrinsic variability and a change in their amplitude. These findings suggest the potential utility of SST forecasts for the tropical Indian Ocean

Simulations of the Atmospheric Response to South Atlantic Sea Surface Temperature Anomalies

The sensitivity of the atmospheric circulation to sea surface temperature (SST) anomalies in the tropical and subtropical South Atlantic Ocean is studied by means of simulations with an atmospheric general circulation model (GCM). Two types of prescribed SST anomalies are used, motivated by previous analyses of data. The first occurs during austral summers in association with a strengthening of the South Atlantic convergence zone (SACZ) and consists of cold SST anomalies over the subtropical South Atlantic. The second is the leading seasonally varying empirical orthogonal function of SST, consisting of warm basin-scale anomalies with maximum amplitude in the subtropics during January–March and at the equator in June. An ensemble of about 10 seasonal simulations is made using each type of anomaly, focusing on the January–March period in the first case and the January–June seasonal evolution in the second. During January–March both experiments yield a statistically significant baroclinic response over the subtropical Atlantic with dipolar SACZ-like anomalies. Some evidence of positive feedback is found. The response is shown to be fairly similar in pattern as well as amplitude to the linear regression of observed interannual low-level wind anomalies with subtropical SST anomalies. However, in the first experiment with cold SST anomalies, the simulated response contrasts with the leading interannual mode of observed SACZ variability. Warm basin-scale anomalies are found to have their largest impact during boreal summer, with a strong statistically significant equatorial baroclinic response and positive rainfall anomalies over the equatorial ocean. The latter do not extend appreciably into the adjacent continents, although there are significant positive rainfall anomalies over the Sahel in April–June and negative anomalies over the western Indian Ocean. In the upper troposphere, a statistically significant wave train extends southwestward to southern South America and northeastward to Europe in April–June, while there is some linkage between the tropically and subtropically forced responses during January–March

Low Dopamine D2/D3 Receptor Availability is Associated with Steep Discounting of Delayed Rewards in Methamphetamine Dependence.

BackgroundIndividuals with substance use disorders typically exhibit a predilection toward instant gratification with apparent disregard for the future consequences of their actions. Indirect evidence suggests that low dopamine D2-type receptor availability in the striatum contributes to the propensity of these individuals to sacrifice long-term goals for short-term gain; however, this possibility has not been tested directly. We investigated whether striatal D2/D3 receptor availability is negatively correlated with the preference for smaller, more immediate rewards over larger, delayed alternatives among research participants who met DSM-IV criteria for methamphetamine (MA) dependence.MethodsFifty-four adults (n = 27 each: MA-dependent, non-user controls) completed the Kirby Monetary Choice Questionnaire, and underwent positron emission tomography scanning with [(18)F]fallypride.ResultsMA users displayed steeper temporal discounting (p = 0.030) and lower striatal D2/D3 receptor availability (p < 0.0005) than controls. Discount rate was negatively correlated with striatal D2/D3 receptor availability, with the relationship reaching statistical significance in the combined sample (r = -0.291, p = 0.016) and among MA users alone (r = -0.342, p = 0.041), but not among controls alone (r = -0.179, p = 0.185); the slopes did not differ significantly between MA users and controls (p = 0.5).ConclusionsThese results provide the first direct evidence of a link between deficient D2/D3 receptor availability and steep temporal discounting. This finding fits with reports that low striatal D2/D3 receptor availability is associated with a higher risk of relapse among stimulant users, and may help to explain why some individuals choose to continue using drugs despite knowledge of their eventual negative consequences. Future research directions and therapeutic implications are discussed

An integrated CFD/experimental analysis of aerodynamic forces and moments

Aerodynamic analysis using computational fluid dynamics (CFD) is most fruitful when it is combined with a thorough program of wind tunnel testing. The understanding of aerodynamic phenomena is enhanced by the synergistic use of both analysis methods. A technique is described for an integrated approach to determining the forces and moments acting on a wind tunnel model by using a combination of experimentally measured pressures and CFD predictions. The CFD code used was FLO57 (an Euler solver) and the wind tunnel model was a heavily instrumented delta wing with 62.5 deg of leading-edge sweep. A thorough comparison of the CFD results and the experimental data is presented for surface pressure distributions and longitudinal forces and moments. The experimental pressures were also integrated over the surface of the model and the resulting forces and moments are compared to the CFD and wind tunnel results. The accurate determination of various drag increments via the combined use of the CFD and experimental pressures is presented in detail