A double-pulsar system: a rare laboratory for relativistic gravity and plasma physics

The clocklike properties of pulsars moving in the gravitational fields of their unseen neutron-star companions have allowed unique tests of general relativity and provided evidence for gravitational radiation. We report here the detection of the 2.8-second pulsar J0737-3039B as the companion to the 23-millisecond pulsar J0737-3039A in a highly relativistic double neutron star system, allowing unprecedented tests of fundamental gravitational physics. We observed a short eclipse of J0737-3039A by J0737-3039B and orbital modulation of the flux density and the pulse shape of J0737-3039B, probably because of the influence of J0737-3039A's energy flux on its magnetosphere. These effects will allow us to probe magneto-ionic properties of a pulsar magnetosphere.     

Urban forest values in Canada: Views of citizens in Calgary and Halifax

A significant component of the urban ecosystem is the urban forest. It is also the quintessential meeting point of culture and nature, so it is critical to incorporate values-based approaches to managing them. The values that really count are those of urban citizens. A novel qualitative method was used to determine what qualities of the urban forest are valued by citizens of Calgary, Alberta, and Halifax, Nova Scotia, Canada. These values were compared with those reported in the literature to reveal that citizens value the urban forests mostly for their non-material benefits. Specifically, urban forests contribute to human emotional, intellectual, and moral fulfilment.     

Endothelial hyperpolarizing factor increases acetylcholine-induced vasodilatation in pulmonary hypertensive broilers arterial rings

Salmonellosis is an important disease of cattle caused predominantly by Salmonella enterica serotypes Typhimurium (S. typhimurium) and Dublin (S. dublin). S. typhimurium causes acute enteritis and exudative diarrhea in calves. In addition to enteric disease, S. dublin can cause systemic infections, and may cause abortion in pregnant cows. Calves are considered a relevant model for non-typhoidal salmonellosis in humans. Experimental oral infections or inoculation of ligated ileal loops in calves have been extensively studied recently. This article reviews relevant published results regarding bovine salmonellosis as a natural disease or as an animal model.     

Pharmacokinetic evaluation of oral dantrolene in the dog

The pharmacokinetics of dantrolene and its active metabolite, 5‐hydroxydantrolene, after a single oral dose of either 5 or 10 mg/kg of dantrolene was determined. The effects of exposure to dantrolene and 5‐hydroxydantrolene on activated whole‐blood gene expression of the cytokines interleukin‐2 (IL‐2) and interferon‐γ (IFN‐γ) were also investigated. When dantrolene was administered at a 5 mg/kg dose, peak plasma concentration (C_max) was 0.43 μg/mL, terminal half‐life (t_1/2) was 1.26 h, and area under the time–concentration curve (AUC) was 3.87 μg·h/mL. For the 10 mg/kg dose, C_max was 0.65 μg/mL, t_1/2 was 1.21 h, and AUC was 5.94 μg·h/mL. For all calculated parameters, however, there were large standard deviations and wide ranges noted between and within individual dogs: t_1/2, for example, ranged from 0.43 to 6.93 h, C_max ratios ranged from 1.05 to 3.39, and relative bioavailability (rF) values ranged from 0.02 to 1.56. While activated whole‐blood expression of IL‐2 and IFN‐γ as measured by qRT‐PCR was markedly suppressed following exposure to very high concentrations (30 and 50 μg/mL, respectively) of both dantrolene and 5‐hydroxydantrolene, biologically and therapeutically relevant suppression of cytokine expression did not occur at the much lower drug concentrations achieved with oral dantrolene dosing.     

Economic Optimum Nitrogen Fertilization Rates and Nitrogen Fertilization Rate Effects on Tuber Characteristics of Potato Cultivars

The objective of the research was to determine the economic optimum nitrogen (N) fertilization rates and to determine the effects of N fertilization rates on tuber characteristics and fresh mass loss after storage under cold and ambient conditions of four potato cultivars, Ágata, Asterix, Atlantic, and Monalisa. The experiments were, simultaneously, conducted in the same area and similar experimental conditions during the fall/winter period in Viçosa, Minas Gerais State, Brazil. In each experiment, five N fertilization rates (0, 50, 100, 200, 300 kg ha^?1) were evaluated in a randomized complete block design. For all cultivars, increasing N fertilization rate increased total and marketable yields and tuber dry matter yield up to a maximum following a quadratic model. Increasing N fertilization rate linearly increased the tuber protein concentration of Atlantic and Monalisa and had no effect on tuber pH. N fertilization rate effects on tuber mass, tuber titratable acidity, and fresh mass loss during storage were cultivar-dependent. N use efficiency (tuber yield divided by N fertilization rate) decreased with increase in N fertilization rate. The economic optimum N fertilization rates ranged from 147 to 201 kg ha^?1 depending upon cultivar and relative prices of N and potato tubers. Depending on the cultivar, under favorable price conditions (low N price and high tuber price), the economic optimum N fertilization rates to be applied by potato growers were 92–95% of the estimated N fertilization rate for obtaining the maximum potato yield, whereas under unfavorable conditions (high N price and low potato tuber price) the economic optimum N fertilization rates to be applied should be decreased to 86–92% of the rates for maximum yield.     

Effects of rapid global warming at the Paleocene-Eocene boundary on neotropical vegetation

Temperatures in tropical regions are estimated to have increased by 3° to 5°C, compared with Late Paleocene values, during the Paleocene-Eocene Thermal Maximum (PETM, 56.3 million years ago) event. We investigated the tropical forest response to this rapid warming by evaluating the palynological record of three stratigraphic sections in eastern Colombia and western Venezuela. We observed a rapid and distinct increase in plant diversity and origination rates, with a set of new taxa, mostly angiosperms, added to the existing stock of low-diversity Paleocene flora. There is no evidence for enhanced aridity in the northern Neotropics. The tropical rainforest was able to persist under elevated temperatures and high levels of atmospheric carbon dioxide, in contrast to speculations that tropical ecosystems were severely compromised by heat stress.     

Identifying resistance gene analogs associated with resistances to different pathogens in common bean

ABSTRACT A polymerase chain reaction approach using degenerate primers that targeted the conserved domains of cloned plant disease resistance genes (R genes) was used to isolate a set of 15 resistance gene analogs (RGAs) from common bean (Phaseolus vulgaris). Eight different classes of RGAs were obtained from nucleotide binding site (NBS)-based primers and seven from not previously described Toll/Interleukin-1 receptor-like (TIR)-based primers. Putative amino acid sequences of RGAs were significantly similar to R genes and contained additional conserved motifs. The NBS-type RGAs were classified in two subgroups according to the expected final residue in the kinase-2 motif. Eleven RGAs were mapped at 19 loci on eight linkage groups of the common bean genetic map constructed at Centro Internacional de Agricultura Tropical. Genetic linkage was shown for eight RGAs with partial resistance to anthracnose, angular leaf spot (ALS) and Bean golden yellow mosaic virus (BGYMV). RGA1 and RGA2 were associated with resistance loci to anthracnose and BGYMV and were part of two clusters of R genes previously described. A new major cluster was detected by RGA7 and explained up to 63.9% of resistance to ALS and has a putative contribution to anthracnose resistance. These results show the usefulness of RGAs as candidate genes to detect and eventually isolate numerous R genes in common bean.     

Evaluation of progesterone levels in feces of captive reticulated giraffe (Giraffa camelopardalis reticulata).

Fresh fecal samples were collected from seven adult female reticulated giraffe (Giraffa camelopardalis reticulata). Samples were collected for several weeks before, during, and for a few weeks after gestation. Fecal samples were analyzed for progesterone levels by radioimmunoassay. There were significant differences in progesterone levels between pregestational and gestational samples and between gestational and postgestational samples. These results demonstrate that fecal progesterone levels are useful in determining pregnant versus nonpregnant reticulated giraffe.