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Planetary rings are observed not only around giant planets1, but also around small bodies such as the Centaur Chariklo2and the dwarf planet Haumea3. Up to now, all known dense rings were located close enough to their parent bodies, being inside the Roche limit, where tidal forces prevent material with reasonable densities from aggregating into a satellite. Here we report observations of an inhomogeneous ring around the trans-Neptunian body (50000) Quaoar. This trans-Neptunian object has an estimated radius4of 555 km and possesses a roughly 80-km satellite5(Weywot) that orbits at 24 Quaoar radii6,7. The detected ring orbits at 7.4 radii from the central body, which is well outside Quaoar’s classical Roche limit, thus indicating that this limit does not always determine where ring material can survive. Our local collisional simulations show that elastic collisions, based on laboratory experiments8, can maintain a ring far away from the body. Moreover, Quaoar’s ring orbits close to the 1/3 spin–orbit resonance9with Quaoar, a property shared by Chariklo’s2,10,11and Haumea’s3rings, suggesting that this resonance plays a key role in ring confinement for small bodies.

As complex autonomous systems emerge in the maritime sector, measures must be taken in order to ensure thorough safety assessment. Real-world testing can be costly and potentially dangerous, and therefore there is a need for suitable simulation-based methods. This paper presents an implementation of the Adaptive Stress Testing (AST) method applied to the collision avoidance (COLAV) system of a small passenger ferry. AST is a simulation-based technique which has shown promising results in safety assessment of aviation and automobile systems. Given a simulator of a system, AST uses reinforcement learning to optimize toward system failure, and returns the most likely failure scenarios. AST is here shown to successfully identify scenarios where the criteria for failure are met, which is when the ferry collides with an adversary vessel controlled by AST. However, most of the initial results exhibit failures where the COLAV system of the ferry is not responsible for the failure, making the results less valuable to system developers. To improve the relevance, augmentations are made to the optimization problem. The augmentations result in four distinct problem formulations presented in the paper. Finally, the results are clustered using an unsupervised machine learning method called Soft Dynamic Time Warping k-means clustering in order to present a general summary of the identified failure scenarios. Our results demonstrate the relevance and potential of AST for the maritime sector and illustrate how common drawbacks of AST can be circumvented by method adjustment.

Early treatment is associated with improved outcomes in patients with rheumatoid arthritis (RA), suggesting that a 'window of opportunity', in which the disease is most susceptible to disease-modifying treatment, exists. Autoantibodies and markers of systemic inflammation can be present long before clinical arthritis, and maturation of the immune response seems to coincide with the development of RA. The pre-arthritis phase associated with symptoms such as as joint pain without clinical arthritis (athralgia) is now hypothesized to fall within the aforementioned window of opportunity. Consequently, disease modulation in this phase might prevent the occurrence of clinically apparent arthritis, which would result in a persistent disease course if untreated. Several ongoing proof-of-concept trials are now testing this hypothesis. This Review highlights the importance of adequate risk prediction for the correct design, execution and interpretation of results of these prevention trials, as well as considerations when translating these findings into clinical practice. The patients' perspectives are discussed, and the accuracy with which RA development can be predicted in patients presenting with arthralgia is evaluated. Currently, the best starting position for preventive studies is proposed to be the inclusion of patients with an increased risk of RA, such as those identified as fulfilling the EULAR definition of 'arthralgia suspicious for progression to RA'.

‘Tift 10’ (Reg. No. CV‐277, PI 674816; PP25,515), ‘Tift 11’ (Reg. No. CV‐278, PI 674817; PP25,514), and ‘Tift 40’ (Reg. No. CV‐279, PI 674820; PP25,518) are trispecific ornamental Pennisetumhybrids approved for release by the University of Georgia College of Agricultural and Environmental Sciences in 2012. They were selected from crosses between P. purpureumSchumach, P. squamulatumFresen. and P. glaucum(L.) R. Br. These trispecific hybrids are both pollen and seed sterile. Tift 10, Tift 11, and Tift 40 are vegetatively propagated cultivars that are perennial in USDA hardiness zones 8b to 10. However, they can be grown as vigorous annuals in more northern zones. Tift 10 is morphologically similar in canopy diameter, culm‐leaf angle, and leaf length but tends to be taller, have wider leaves, and have better color compared with ‘Princess Caroline’. Tift 11 is morphologically similar in canopy diameter and color but tends to be taller, have a wider canopy diameter, have narrower and shorter leaves, and have a smaller culm‐leaf angle compared with Princess Caroline. Tift 40 is taller, has better color, and has a larger culm‐leaf angle, as well as longer and wider leaves, compared with Princess Caroline. Tift 10, Tift 11, and Tift 40 are significantly more resistant to Helminthosporiumleaf spot than ‘Princess’. These cultivars flower under short days and therefore will not produce inflorescences where winter temperatures reach freezing (0°C) or below before the daylength is 10.5 h.

Objective.The purpose of this study was to evaluate the impact of an interprofessional medical service trip to rural Honduras on pharmacy and medical learners’ attitudes toward interprofessional learning.

Spiral fractures of long bones have long been cited as indications of non-accidental trauma (NAT) in children; however, fracture types are only loosely defined in the literature, and intraobserver and interobserver variability in defining femoral fracture patterns is rarely mentioned. We sought to determine reliability in classifying femoral fractures in young children using a standard series of radiographs shown to physicians with varied backgrounds and training and to determine if a quantitative approach based on objective measurements made on plain radiographs could improve definition of these fractures.

‘Tift 8’ (Reg. No. CV‐259, PI 659801) is a trispecific ornamental hybrid of Pennisetumapproved for release by the University of Georgia College of Agricultural and Environmental Sciences in 2010. It was produced from crosses between P. purpureumSchumach; P. squamulatumFresen.; and P. glaucum(L.) R. Br. This trispecific hybrid is both pollen and seed sterile. Tift 8 is a vegetatively propagated cultivar that is perennial in USDA hardiness zones 8–10. It can be grown as a vigorous annual in more northern zones. Tift 8 is morphologically similar to ‘Tift 17’, but it is significantly taller and has a significantly smaller culm‐leaf angle than Tift 17. Tift 8 is significantly more resistant to Helminthosporium leaf spot (caused by Helminthosporium ocellumFaris) than ‘Princess’. Mature leaves of Tift 8 have a reddish‐purple color. The plant color of Tift 8 is equal to, and in some tests better than, that of Tift 17. Tift 8 flowers under short days; therefore, it will not produce inflorescences where winter temperatures reach freezing (0°C) or below, or before the daylength is 10.5 h. A plant patent application has been submitted for Tift 8.

TifQuik' (Reg. No. CV‐4, PI 648303, PVP No 200700209) is a fast emerging forage bahiagrass (Paspalum notatumFlügge) released by the University of Georgia–Tifton Campus and the USDA‐ARS in 2008. The current forage bahiagrass cultivars have a considerable amount of hard seed and thus require 2 or 3 wk to establish a full stand, during which time weeds may infest the pasture or moisture for germination may be restricted. The purpose of the breeding program that produced TifQuik was to select for an increased rate of germination and emergence. TifQuik was produced by employing four cycles of recurrent restricted phenotypic selection for improving the emergence and establishment rates originating from ‘Tifton 9’ bahiagrass. TifQuik had a fourfold improvement of emergence compared with Tifton 9 after 1 wk in greenhouse trials. Emergence rates, plant heights after 3 wk from planting, and first harvest yields were significantly greater for TifQuik than for other cultivars in replicated field trials. The accelerated emergence and establishment of TifQuik will be useful in sod‐based rotation systems with cotton (Gossypium hirsutumL.) and peanut (Arachis hypogaeaL.).

Apospory in Pennisetum squamulatumFresen is inherited as a single‐locus dominant trait. Molecular analysis has identified the apospory‐specific genomic region (ASGR), a large segment of one chromosome that is necessary and sufficient to confer apomixis. To transfer apospory from P. squamulatumto pearl millet [P. glaucum(L.) R. Br.], advanced backcrosses were generated. Here we report the characterization of apomictic BC7and BC8generations. A BC7–derived genotype has two P. squamulatumchromosomes, while BC8–derived apomictic lines inherited only the ASGR chromosome that confers apospory to pearl millet. Morphologically, no significant differences were observed between backcross generations for plant height, leaf length, leaf width, and first internode and inflorescence lengths. However, the BC7and BC8lines differed significantly with regard to pollen viability, flowering time, and seed set. Pollen viability increased to 81% in the BC8lines compared with 37% in BC7. The frequency of aposporous embryo sacs was lower in BC8(79%) lines compared to BC7(93%). Meiotic behavior of chromosomes during metaphase I and anaphase I showed that BC8typically had a single univalent, identified as the ASGR chromosome by FISH (fluorescence in situ hybridization) and GISH (genomic in situ hybridization). Utilizing its unique behavior during meiosis the ASGR chromosome was microdissected and a chromosome‐specific library was constructed and sequenced. Analysis of sequences identified both novel and previously known ASGR‐linked sequences.

The tetraploid germplasm of bahiagrass, Paspalum notatumFlüggé, is an unexploited source of variability that can be used for the genetic improvement of this species as forage or turf. The objectives of this research were to develop a segregating population by hybridizing induced sexual and apomictic clones and to characterize the resulting population for mode of reproduction, seed fertility, growth habit, seasonal growth pattern, and frost resistance. A population of 591 hybrids had a 4:1 ratio between sexual and apomictic (facultative + obligate apomictic) plants and an 8:1 ratio between others (facultative apomictic + sexual) and obligate apomictic plants. The general fertility of the progeny was higher than that of the induced sexual parents. Significant differences were observed for self‐ and cross‐fertility among apomictic progeny and for self‐fertility among sexual progeny. Most sexual progeny set the same amount of seed when self‐ or cross‐ pollinated, indicating an absence of self‐incompatibility. Marked variation was observed for growth habit, seasonal growth patterns, and frost resistance among the progeny. Heritability estimates obtained for these characteristics indicate that selection can be successfully used for the genetic improvement of this species.

Bahiagrass (Paspalum notatum Flüggé) is one of the major forage grasses used for beef cattle production in the southern USA. Description of the reproductive characteristics of bahiagrass germplasm is needed for genetic improvement of this forage crop. The objective was to determine and compare the mode of reproduction of diploid and tetraploid germplasm of bahiagrass. Reproductive behavior was determined by embryo sac observations and a series of controlled pollination studies in the greenhouse and field in 2004 and 2005. Two sexual diploid populations (‘Pensacola’ and ‘Tifton 9’) were not different in self‐ or cross‐fertility, indicating that the general fertility of the crop was not affected by phenotypic mass selection. Sexual diploids, as a group, were determined to be primarily cross‐pollinated, with low but variable levels of self‐fertility. A group of 20 artificially induced tetraploids was determined to be primarily sexual and cross‐pollinated. Fertility of these autotetraploids was lower than the original diploids. Two selected sexual tetraploids produced similar amounts of seed when self‐ or cross‐pollinated. In contrast, six other tetraploids, including the cultivars Argentine and Wilmington, the experimental hybrid Tifton 7, and three plant introductions 315732, 315733, and 315734 reproduced primarily by apomixis. The sexual or apomictic expression, the general fertility, and other agronomic characteristics of these groups of tetraploids define their usefulness for genetic improvement research.

Pearl millet is widely consumed in regions of Africa and Asia, and is increasingly being grown as an alternative grain in drought-prone regions of the United States. Pearl millet and corn were grown in dryland conditions at Tifton, Georgia, USA and grains were compared for pre-harvest infection by potentially toxigenic fungi and contamination by mycotoxins. Corn hybrids Agripro 9909 and Pioneer 3146, and pearl millet Tifgrain 102 were grown in 2000 and 2001; pearl millet HGM 100 was included in the test in 2001. Hybrids were sown on multiple planting dates in each year to induce variation in flowering time. Host species differed in the frequency of isolation of potentially toxigenic fungal species in both years. Across years, corn hybrids were more prone to infection by Aspergillus flavus Link (maximum isolation frequency = 8.8%) and Fusarium moniliforme Sheldon sensu lato (maximum isolation frequency = 72.8%), with corresponding greater concentrations of aflatoxins (maximum concentration = 204.9 μg kg−1) and fumonisins (maximum concentration = 34,039 μg kg−1). Pearl millet was more prone to infection by F. semitectum Berk. & Ravenel (maximum isolation = 74.2%) and F. chlamydosporum Wollenweb & Reinking (maximum isolation = 33.0%), and contamination by moniliformin (maximum contamination = 92.1 μg kg−1). Beauvericin (maximum concentration = 414.6 μg kg−1) was present in both hosts. Planting date of corn affected aflatoxin and beauvericin contamination in 2000, and fumonisin concentration in 2001. The observed differences in mycotoxin contamination of the grains, which are likely due to host-specific differences in susceptibility to pre-harvest mycoflora, may affect food safety when the crops are grown under stress conditions.

Peptide deformylase (PDF) has been identified as a promising antibacterial and herbicide target. A structurally novel class of inhibitors containing a 2-thioxo-thiazolidin-4-one heterocycle substituted by an arylidene group at the 5-position and a hexanoic acid side chain at the 3-position was discovered independently via high-throughput screening and virtual ligand screening. Data mining and analogue synthesis established a structure−activity relationship for the side chain region that is consistent with the docked structure.

Pearl millet [ Pennisetum glaucum (L.) R. Br.] is a drought-tolerant cereal crop used for grain and forage. Novel traits from outside of the gene pool could be introduced provided a reliable gene-transfer method were available. We have obtained herbicide-resistant transgenic pearl millet plants by microprojectile bombardment of embryogenic tissues with the bar gene. Embryogenic tissues derived from immature embryos, inflorescences and apical meristems from diploid and tetraploid pearl millet genotypes were used as target tissues. Transformed cells were selected in the dark on Murashige and Skoog medium supplemented with 2 mg/l 2,4-D and 15 mg/l phosphinothricin (PPT). After 3–10 weeks in the dark, herbicide-resistant somatic embryos were induced to germinate on MS medium containing 0.1 mg/l thidiazuron and 0.1 mg/l 6-benzylaminopurine. Plants were transferred to the greenhouse after they were rooted in the presence of PPT and had passed a chlorophenol red assay (the medium turned from red to yellow). Transgenic plants were recovered from bombardments using intact pAHC25 plasmid DNA, a gel-purified bar fragment, or a mixture of pAHC25 plasmid or bar fragment and a plasmid containing the enhanced green fluorescent protein ( gfp) gene (p524EGFP.1). Analyses by the polymerase chain reaction, Southern blot hybridization, GFP expression, resistance to herbicide application, and segregation of the bar and gfp genes confirmed the presence and stable integration of the foreign DNA. Transformed plants were recovered from all three explants, although transformation conditions were optimized using only the tetraploid inflorescence. Time from culture initiation to rooted transgenic plant using the tetraploid inflorescence ranged from 3–4 months. Seven independent DNA/gold precipitations were used to bombard 52 plates, 29 of which produced an average of 5.5 herbicide-resistant plants per plate. The number of herbicide-resistant plants recovered per successful bombardment ranged from one to 28 and the frequency of co-transformation with gfp ranged from 5% to 85%.

Abstract:  Bermudagrasses (Cynodon spp.) are major turfgrasses for home lawns, public parks, golf courses and sport fields, and are widely adapted to tropical and warmer temperate climates. Morphological and physiological characteristics are not sufficient to differentiate some bermudagrass genotypes because the differences between them are often subtle and subject to environmental influence. In this study, a DNA-typing technique, amplified fragment length polymorphism (AFLP), was used to differentiate bermudagrass genotypes and to explore their genetic relationships. Twenty seven bermudagrass cultivars and introductions, mostly from the Coastal Plain Experiment Station in Tifton, Ga., were assayed by the radioactive (32P) and the fluorescence-labeled AFLP methods. The AFLP technique produced enough polymorphism to differentiate all 27 bermudagrass genotypes, even the closely related ones. An average of 48–74 bands in the 30–600-bp size range was detected by the 32P-labeled AFLP method. The results indicated that most of the 14 primer combinations tested in this study could be used to distinguish bermudagrass genotypes, and that some single primer-pairs could differentiate all 27 of them. To test the reliability and reproducibility of the AFLP procedure, three DNA isolations (replications) of the 27 bermudagrass genotypes were assayed using five primer pairs. Only 0.6% of the bands were evaluated differently among the three replications. One replication of one genotype (which was most likely a planting contaminant) was grouped in an unexpected cluster using the Unweighted Pair Group Mean Average (UPGMA) method. A one- or two-band difference in scoring did not change the clustering of genotypes or the replications within genotypes. The 27 genotypes were grouped into three major clusters, many of which were in agreement with known pedigrees. Trees constructed with different primer combinations using 32P- and fluorescence-labelling formed similar major groupings. The semi-automated fluorescence-based AFLP technique offered significant improvements on fragment sizing and data handling. It was also more accurate for detection and more efficient than the radioactive labelling method. This study shows that the AFLP technique is a reliable tool for differentiating bermudagrass genotypes and for determining genetic relationships among them.

The clinical course and coagulation profile of a pregnant patient with variant von Willebrand's disease were followed from the second trimester through puerperium. The clinical course was characterized by a normal delivery and absence of abnormal bleeding or need for replacement therapy. The coagulation profile demonstrated an increase in factor VIII procoagulant activity, factor-VIII-related antigen, and platelet aggregation activity in response to ristocetin prior to delivery. Postpartum, these factors decreased to prepregnancy values with distinctly different patterns. Factor VIII procoagulant activity continued to rise for 5 days after delivery and then decreased with a half-life of approximately 6 days. Factor-VIII-related antigen began to decrease just prior to delivery, displaying a half-life or approximately 6 days. Ristocetin cofactor activity, however, dropped immediately postpartum and displayed a half-life of approximately 6 hr. The ristocetin cofactor activity was associated with factor-VIII- related antigen, which displayed a significantly smaller molecular weight than does normal factor-VIII-related antigen. Larger aggregates of factor-VIII-related antigen. Larger aggregates of factor-VIII- related antigen did not appear during the pregnancy, and ristocetin cofactor activity could not be demonstrated in fragments of less than 0,8 x 10(6).

Reduced lignin contents in brown midrib (bmr) mutants of sorghum (Sorghum bicolorL. Moench.) are reported to improve the digestibility of this forage. The objective of this study was to evaluate microscopically leaf blades of normal‐(N) 12 and bmr‐12 sorghum for variations in anatomy, histological reactions of tissues for lignin, and specific tissue digestion to elucidate the contribution of the bmr‐ 12 mutation to improved forage quality. No differences in anatomy or histology of lignified tissues was observed between N‐12 and bmr‐ 12 plants. Midribs of N and bmr plants, examined by scanning electron microscopy after a 48 to 72 h incubation with rumen fluid were partially degraded, with a tendency for parenchyma in bmr leaf blades to be more degraded than that in N leaf blades. Other tissues, i.e., epidermis and xylem, were not degraded in either plant type. In the non‐midrib portion of blades, the parenchyma bundle sheaths and adaxial sclerenchyma areas were degraded to a greater extent in bmr plants by mixed rumen microorganisms and by a pure culture of the cell wall‐degrading rumen bacterium Ruminococcus flavefaciensFD‐1. Epidermis and mesophyll at times more rapidly degraded in bmr plants. In leaf sheaths, no marked differences in digestion between N and bmr plants were found with parenchyma totally degraded in both plant types. Xylem and other tissues normally highly resistant to microbial degradation were not degraded in plant parts of either N or bmr types. The bmr‐12 mutation did not result in changes in leaf blade anatomy or histological reactions for lignin and did not result in susceptibility to microbial degradation of the most resistant tissues. The bmr‐12 mutation did allow an improved microbial degradation of marginally digestible tissue, i.e., those tissues usually only poorly degraded.

Marginally digested tissues in the brown midrib‐12 (bmr) sorghum (Sorghum bicolor(L.) Moench.) mutant are more readily degraded than similar tissues in the normal (N) line. Reduced lignin concentrations have been reported to be a factor affecting digestibility of bmr genotypes, but lignin type could also influence digestibility. The objectives of this work were to (i) examine N‐12 and bmr‐12 plants for variations in chemical composition, including phenolic acids and phenolic structure, using solid‐state nuclear magnetic resonance (NMR) spectroscopy; and (ii) evaluate by microscopy the effect of permanganate delignification. Leaf blades of bmr plants were significantly (Ρ≤ 0.05) lower in neutral detergent fiber (NDF) and permanganate lignin (PML), and higher in in vitro dry matter digestibility; leaf sheaths contained significantly less PML. Solid‐state NMR spectroscopy suggested that bmr leaf blades had lower amounts of bound syringyl moieties. The predominant alkali‐soluble (1.0 M NaOH) phenolic acids in both plant types were ρ‐coumaric and ferulic acids, and ρ‐coumaric acid was significantly lower (Ρ ≤ 0.05) in concentration in bmr leaves. Treatment of intact blade sections with permanganate to oxidize lignin compounds resulted in a reduced staining intensity for lignin identified by both the acid phloroglucinol and chlorine‐sulfite tests in all but midrib sclerenchyma; lignin staining intensity did not differ between plant types. Degradation of delignified midribs by rumen microbes indicated that the tissues were more degradable in bmr than in N plant types. Results suggest that reduced concentrations of phenolic acids (especially ρ‐coumaric acid) and reduced levels of etherated syringyl moieties in conjunction with reduced concentrations of lignin are factors in the improved quality of bmr‐12 sorghum.

Studies were conducted to assess nutritional value of pearl millet grain (Pennisetum glaucum[L] R. Br.) for lactating and growing goats. Three complete diets containing either 40% corn, 40% pearl millet, or 40% corn and pearl millet mixed 1:1 (wt/wt) were balanced to contain 16% crude protein and 2.24 Mcal DE/kg on an air-dry basis. Forty-five does were blocked by kidding date and randomly assigned to diets for a 7-wk investigation. Feed intake and milk production were unaffected (P> .25) by treatment, and they averaged 2.86 and 2.47 kg daily, respectively. Thirty-three growing goats were blocked by sex and fed the same diets for 15 wk. Daily growth rate and feed to gain ratio were depressed (P< .05) by 25.4 and 19.0%, respectively, when corn was completely replaced with pearl millet. Digestion coefficients for DM, GE, CP, and NDF were reduced by over 10 percentage units with partial or complete replacement of corn by pearl millet. Ruminal acetate and ratio of acetate to propionate increased (P< .05) but butyrate, propionate, and ammonia were depressed (P< .05) with the pearl millet diets. Growing goats consumed 43 meals daily. They consumed 26.9, 32.6, 27.4, and 13.1% of their ration during the morning (0600 to 1200), afternoon (1200 to 1800), evening (1800 to 2400), and night (2400 to 0600), respectively. Pearl millet is a useful energy feed for mature, but not for growing, goats.

Comparative studies examining relative forage digestibilities of small‐grain species and genotypes are lacking. Pattern and extent of digestion and microanatomical characteristics of fresh leaves and stems were evaluated in two genotypes each of rye (Secale cerealeL.), soft red winter wheat (Triticum aestivumL.), oat (Avena sativaL.), and triticale (✕ TriticosecaleWittmack). Field grown plants (mid‐boot) were sampled in 1987 and 1988 at Tifton, GA. In 1987, leaf and stem anatomy were compared microscopically in fresh nondigested samples. Fresh leaf and stem segments (2.5 cm) were digested 36 h in buffered rumen fluid, serially sectioned, and examined microscopically to examine the ease and extent of digestion in specific tissues. In 1988, in vitro dry matter disappearance (IVDMD) was determined in ground (1 mm) and intact stem and leaf sections (1 cm) digested for 12, 24, 36, and 48 h. No microanatomical variation was observed among genotypes of the same species. Variation was observed among species in stem signification, stem sclerenchyma cell‐wall thickness and arrangement, compaction, and shape of leaf mesophyll cells. Signified stem tissue was greatest in wheat and triticale and least in oat and rye. Rye leaf mesophyll cells were the least compact with the largest intercellular spaces. Variation was observed among species in digestibility of leaf and stem bundle sheath cells. Differentiation among genotypes for leaf IVDMD was greater in sectioned samples digested 12 to 36 h than in ground samples digested 48 h. Species varied in leaf and stem IVDMD. Oat had the lowest stem digestibility but the highest leaf digestibility. Variation for forage digestibility was observed among genotypes of all species except triticale. Variation in forage digestibility was not associated with variation observed for stem signification or arrangement and compaction of leaf mesophyll cells. Adequate variability exists within rye and oat to suggest that selection for leaf IVDMD would be effective in improving small‐grain forage quality.

To determine the potential for germplasm exchange, interspecific hybrids from a cross between a pearl millet Pennisetum glaucum(L.) R. Br. ✕ Pennisetum purpureumSchum. amphiploid crossed with a P. glaucum✕ Pennisetum squamulatumFresen. interspecific hybrid were backcrossed four times to tetraploid pearl millet. The objective of this research was to determine the chromosomal characteristics of progeny obtained from pollinating both cytoplasmic nuclear male sterile diploid (2n= 14) and tetraploid (2n= 28) pearl millet with near‐tetraploid (2n= 26 to 32) BC4derivatives involving P. glaucum, P. purpureum, and P. squamulatum. Forty‐five BC4plants, 15 of which had chromosome numbers ranging from 26 to 32, were used to pollinate cytoplasmic‐nuclear male sterile diploid and tetraploid pearl millet, giving rise to 10 diploid and 70 neartetraploid BC5progeny, respectively. The recovery of diploid progeny suggests monoploid pollen was produced by the BC4plants. All offspring expressed phenotypic traits of the male parent. Male fertility was restored completely in two diploid hybrids and restored partially in six near‐tetraploid hybrids, probably because of the transfer of P. purpureumand/or P. squamulatumchromatin. Nine BC5diploid offspring had 14 A and/or A' genome chromosomes, which paired as seven bivalents at metaphase I. The near tetraploid BC5offspring had from 27 to 30 chromosomes. Chromosome numbers observed in the young microspores of the BC4plants ranged from n= l to n= 16. These results show that monoploid pollen can be produced from tetraploid or hexaploid hybrids and used for transferring gene(s) from wild relatives into pearl millet.

Apomixis, an asexual method of reproduction through the seed, provides unique opportunities for developing superior cultivars in the future. Apomixis occurs at low levels in some cultivated species and can be found in closely related species of many cultivated crops.The purposes of this paper are to help plant breeders and geneticists recognize apomixis and to show how it can be used in plant improvement. Transfer of apomixis to important crops would make possible development of true‐breeding hybrids and commercial production of hybrids without a need for cytoplasmic male sterility and high cost, labor‐intensive processes. Obligately apomictic hybrids would breed true regardless of heterozygosity. It could also provide an efficient method for incorporating genes into new genotypes. Superior obligate apomictic genotypes would be ready for performance testing without a need for progeny testing to determine genetic stability. The commercial hybrid production process would be simplified with apomictic hybrids. Several apomixis mechanisms have been shown to be genetically controlled and therefore subject to genetic manipulation in plant breeding programs. Characteristics such as: (i) uniform progenies from heterozygous F1or open‐pollinated parents, (ii) maternal types in crosses, (iii) high seed set in unstable genotypes, and (iv) multiple ovules and seedings per ovule are indicators of apomixis that should be investigated.

Breeding procedures used in pearl millet [Pennisetum glaucum(L.) R. Br.] improvement in India and the USA are aimed at exploitation of hybrid vigor for both grain and forage yields. Selection efforts in Africa have been limited to intrapopulation improvement for grain yield. Knowledge of heterotic patterns and combining ability of the widely cultivated African landraces would be useful in the development of a sound breeding program in Africa. The objectives of this study were to evaluate the combining ability and heterosis among African pearl millet populations and to explore the utility of inter‐population improvement for the development of high yielding varieties and hybrids. Five populations and their 10 interpopulation crosses were evaluated in a randomized complete‐block design with six replications at two locations in Niger during the 1989 and 1990 rainy seasons. Plant height, flowering time, natural incidence of downy mildew, spike length, grain yield, and 1000‐seed weight were measured in different populations. Significant differences among entries for most of the traits were observed. Better‐parent heterosis for grain yield ranged from 25 (Iniari × Ugandi) to 81% (Mansori × Ex.Bornu). Six of the crosses showed significant heterosis and gave 36 to 81% more grain yield than their better parent. All crosses except one were significantly more tolerant to downy mildew than their better parent. Mean squares for general combining ability were significant (P< 0.05) for most traits indicating the importance of additive gene effects for these traits. The large heterotic effects and the magnitude of the additive effects observed in the experiment should be useful in choosing pearl millet landraces for intercrossing in the development of cultivars with improved grain yield.

Many of today's landscapes require turfgrasses that can survive extended drought periods without supplemental water. Centipedegrass [Eremochloa ophiuroides(Munro.) Hack.] has long been used as a low‐maintenance lawn grass for the Southeast. A controlled drought study was used to determine the quality, growth, and recovery of centipedegrass held in stress for periods of 7 to 30 d. Common centipedegrass, established under an automated rainfall shelter, was subjected to three drought (drydown) regimes ‐ NOSTRESS, watered twice per week; MODERATE, 2 to 3 wk between watering; and SEVERE, 4 to 6 wk between watering. Soil water was monitored daily to 0.7 m depth with resistance type sensors. Clipping biomass, relative leaf water content, and visual rating were monitored weekly. Available water dropped below 30% in the 0.7 m profile in 7 to 14 d after complete rewetting, and drought stress, indicated by wilting, became evident. The period of drought stress extended for 10 to 30d during which weekly clipping biomass decreased by 50 to 70% below that of NOSTRESS turf. Visual ratings declined along with biomass decrease, falling below acceptable quality rating when drought stress lasted longer than 7 to 10 d. Relative leaf water content declined from about 80% for NOSTRESS to as low as 40% at the end of the SEVERE drought periods. Recovery of leaf water content following watering was not complete, due either to an adaptive response to drydown or to incomplete recovery of the grass. When as much as 3 wk elapsed between watering, irrigation of centipedegrass resulted in recovery of clipping biomass and visual ratings nearly to that of the NOSTRESS treatment. When drought extended for 6 wk, turf quality was low, but centipedegrass survived and recovered to levels suitable for lawns.

1. The Na+ channel mutation associated with equine hyperkalaemic periodic paralysis (HPP) affects a highly conserved phenylalanine residue in an unexplored region of the alpha‐subunit. This mutation was introduced into the rat skeletal muscle Na+ channel gene at the corresponding location (i.e. F1412L) for functional expression and characterization in Xenopus oocytes. 2. In comparison with wild‐type (WT) channels, equine HPP channels showed clear evidence for disruption of inactivation: increased time‐to‐peak current, slowed rates of whole‐cell current decay, significant increases in sustained current, rightward shifts in the steady‐state inactivation curve by 9.5 mV, a 6‐fold acceleration in the rate of recovery from inactivation at ‐80 mV, decreased number of blank single‐channel sweeps, repetitive opening of single channels throughout depolarizing steps, increased open probability per sweep, and an increased mean open time. 3. The observed disruption of inactivation in HPP occurred without measurable changes in steady‐state activation and first latency kinetics of channel opening. 4. Kinetic modelling demonstrates that the equine HPP phenotype can be simulated by altering the rate constants for transitions entering and leaving the inactivated states resulting from an energetic destabilization of the inactivated state. 5. These results suggest that the highly conserved cytoplasmic end of the third transmembrane segment (S3) in the fourth internal repeat domain (domain IV) plays a critical role in Na+ channel inactivation.

The tunnelling as opposed to the open harvest technique for harvesting long saphenous vein for coronary artery bypass procedures is a less frequently used technique as it requires more handling of the vein and this may induce trauma. This study aims to compare the degree of endothelial denudation and donor site morbidity between the two different harvest techniques.

Pearl millet grain was blended with corn in 1:1 or 2:1 ratios in beef finishing diets fed in two metabolism and two feedlot trials. In Exp. 1, diets contained 1) 79.5% corn and 4.5% soybean meal (C-SBM), 2) 28% corn, 54.5% sorghum, and 1.5% soybean meal [GSC(2:1)], and 3) 28% corn and 56% pearl millet [PMC(2:1)]. In Exp. 2, diets contained 1) 81.5% corn and 3.5% soybean meal (C-SBM) or 2) 42.5% corn and 42.5% pearl millet [PMC(1:1)]. Diets fed to steers in metabolism trials in Exp. 1 and 2 had similar (P> .10) apparent digestion coefficients for OM, crude fiber, NDF, and ADF. However, ether extract digestibility was higher (P< .05) for C-SBM than for GSC(2:1) and PMC(2:1) in Exp. 1, and it was higher (P< .10) for C-SBM than for PMC(1:1) in Exp. 2. In both experiments CP digestibility was higher (P< .10) for C-SBM diets, and N retention was similar (P> .10) for diets within each experiment. In each experiment, TDN calculated from apparent digestion coefficients was converted to NEmand NEg. The TDN, NEm, and NEgwere lower (P< .10) for GSC(2:1) and PMC(2:1) than for C-SBM in Exp. 1. Experimental diets were fed to steers (n = 45; 396 ± 19 kg initial BW; 70-d ad libitum feeding) in Exp. 1 and to heifers (n = 30; 318 ± 15 kg initial BW; 92-d ad libitum feeding) in Exp. 2. The ADG, empty body weight gain (EBG), and predicted EBG were not different (P> .10) for diets composed of the different grain sources. Feed DMI and DM per gain were higher (P< .05) for PMC(1:1) than for C-SBM in Exp. 2. Pearl millet supplied approximately 88% as much NEmand 85% as much NEgas the corn-SBM portion of diets having similar CP concentrations.

Microsporogenesis, reproductive behavior, pollen fertility and seed set were studied in Pennisetumbasedowii Summerhayes and C. E. Hubbard, 2n = 54; P. macrostachyum (Brough.) Trin., 2n = 54; P. macrourum Trin., 2n = 36; P. polystachion (L.) Schult, 2n = 54; and P. squamulatum Fresen 2n = 54. Meiosis was regular in P. basedowii with primarily bivalent pairing. As many as 54 univalents were observed at metaphase I in P. macrostachyum. A high frequency of univalents at metaphase I in P. macrourum resulted in lagging chromosomes and micronuclei at anaphase I and telophase I, respectively. Pennisetum polystachion and P. squamulatum showed frequent multivalent chromosome associations. Studies of megasporogenesis and embryo sac development in P. basedowii showed sexual reproduction. Pennisetummacrostachyum was highly male sterile with predominantly aposporous apomictic embryo sac development. Pennisetum macrourum, P. polystachion, and P.squamulatum had only aposporous embryo sac development. Seed propagated progenies of these latter three species were uniform and matromorphic, confirming the obligate apomixis nature.

Plants were regenerated by somatic embryogenesis from cultured leaf segments of Panicum maximum Jacq. (Guinea grass). All plants were phenotypically similar to the donor plant from which expiants were obtained for culture. Examination of the cytological and morphological characteristics of the regenerated plants did not show any changes in mitotic (root tip) chromosome number, structural rearrangements of chromosomes, pollen stainability and morphological characteristics.

The complexation of ferron(7-iodo-8-hydroxy quinoline-5-sulphonic acid) with some metal ions of biological interest, such as Ag(I), Cu(II), Zr(IV), U(VI), Au(III), Ni(II), Zn(II), Mn(II), Fe(II), Fe(III), and Cr(III), has been studied potentiometrically using the Calvin-Bjerrum titration technique as employed by Irving and Rossotti. The protonation constant of the ligand and the stability constants of the respective metal complexes have been determined at constant temperature (25°C) and ionic strength (0.1M KNO3). Complexes of ferron with some metal ions have also been prepared and analyzed by ir. spectral data.

Pearl millet [Pennisetum glaucum(L.) R.Br.] is a warm-season grass used for food, feed, fodder and forage, primarily in countries of Africa and India but grown around the world. The two most-destructive diseases to pearl millet in the United States are rust (caused by Puccinia substriatavar. indica) and pyricularia leaf spot (caused by Pyricularia grisea). Genes for disease resistance to both pathogens have been transferred into agronomically acceptable forage and grain cultivars. A study was undertaken to identify molecular markers for three rust loci and one pyricularia resistance locus. Three segregating populations were screened for RAPDs using random decamer primers and for RFLPs using a core set of probes detecting single-copy markers on the pearl millet map. The rust resistance gene Rr1from the pearl millet subspecies P. glaucumssp. monodiiwas linked 8.5 cM from the RAPD OP-G8350. The linkage of two RFLP markers, Xpsm108(15.5 cM) and Xpsm174(17.7 cM), placed the Rr1gene on linkage-group 3 of the pearl millet map. Rust resistance genes from both Tift 89D2and ICMP 83506 were placed on linkage-group 4 by determining genetic linkage to the RFLP marker Xpsm716(4.9 and 0.0 cM, respectively). Resistance in ICMP 83506 was also linked to the RFLP marker Xpsm306(10.0 cM), while resistance in Tift 89D2was linked to RAPD markers OP-K19350(8.8 cM) and OP-O8350(19.6 cM). Fragments from OP-K19 and OP-O8 in the ICMP 83506 population, and Xpsm306in the Tift 89D2population, were monomorphic. Only one RAPD marker (OP-D11700, 5.6 cM) was linked to pyricularia leaf spot resistance. Attempts to detect polymorphisms with rice RFLP probes linked to rice blast resistance (Pyricularia oryzae; syn=P. grisea) were unsuccessful.

The single recessive trgene when homozygous suppresses all trichomes in pearl millet, Pennisetum americanum(L.) Leeke. By comparing the near‐isogenic Tilt 23S (tr tr) and the pubescent Tilt 23H (Tr Tr) the following pleiotropic effects were discovered. The trgene reduced transpiration from 8.9 to 35.0% in eight genotypes without altering stomate length or frequency. The trgene imparted a smooth wax‐like surface to the cuticle of the leaves that caused the leaves (blades) to accumulate more dew, kept the leaves wet longer, and increased the rate at which rust developed on them. This modified trcuticle apparently reduced in vitro dry matter digestibility (IVDMD) rates in intact leaf sections and slowed the drying rate of excised green leaves. The trgene increased the palatability of pearl millet forage for cattle and tended to increase intake for the first few days of a green feeding test. However, it failed to increase overall livestock gains, probably because the slower digestion rate of trforage slowed its passage through the gastrointestinal tract, reduced intake, and offset its greater palatability. The trgene significantly reduced oviposition of the fall army worm, Spodoptera frugiperdaJ. E. Smith and corn earworm, Heliothis zeaBoddie and reduced the foliar feeding of first and second instar fall army worms fourfold.

We conducted two studies to assess the protein and energy value of pearl millet grain (Pennisetum glaucum[L.] R. Br.) for mature goats. In Exp. 1, 15 2-yr-old male castrated goats were gradually introduced over a 4-mo period to three all-grain diets consisting of 100% corn (Zea maysL.), 50:50 corn:pearl millet, and 100% pearl millet. After the adjustment to all-grain feeds, the goats were fed the diets in metabolism crates for 2-d adjustment and 7-d total collection periods. For Exp. 2, complete diets containing the three grain treatments (corn, 50:50 corn:pearl millet, and pearl millet) as 40% of the total DM as fed (the remainder was mainly alfalfa meal and mineral supplement) were balanced to contain 16% crude protein (CP) and 2.24 Mcal digestible energy (DE)/kg on an air-dry basis. Twelve mature (4- to 6-yr-old) buck goats were randomly assigned to diets and fed in pens for 14 d and then moved to metabolism crates for 10-d adjustment and 10-d total collection periods. In Exp. 1, DM intake was unaffected by dietary treatment, but digestibility of DM and organic matter was lowest (P< .10) in goats fed 100% pearl millet. Digestibility of complete diets also decreased (P< .10) as corn was replaced by 50 or 100% pearl millet, but DM intake increased (P< .10) on the 100% millet diet. In both experiments, substituting pearl millet for corn had no effect on nitrogen retained by the goats. Metabolizable energy of pearl millet was only 92% that of corn, but ME intake was similar when the grains were fed as 40% of the dietary DM. Pearl millet has potential as a major energy feed for goats in areas where it can be economically produced.

Two trials were conducted to compare pearl millet grain with corn and grain sorghum in cattle diets. Grain portions of diets in metabolism and feedlot experiments contained 73% corn and 6% soybean meal (C); 76.2% grain sorghum and 2.8% soybean meal (GS); and 79% pearl millet (PM). In the metabolism trial (replicated 3 × 3 latin squares; six steers), apparent digestibilities of DM and OM were higher (P< .05) for C than for GS or PM diets. Ether extract and CP digestibilities were higher (P< .05) for C and PM than GS. Dietary TDN was higher (P< .05) for C compared with GS or PM diets. Fecal N was higher (P< .05) for GS than for C or PM, urinary N was higher (P< .05) for PM than C or GS, but retained N was similar (P> .05) for C, GS and PM diets. In a 90-d feedlot trial (18 individually fed heifers), a trend was observed for higher (P< .20) ADG on C compared with PM; however, feed/gain was similar for C, GS and PM diets (8.2, 9.1 and 8.5 kg feed/kg gain, respectively). Ruminal fluid acetate:propionate ratios were lower (P< .05) at 3.5 and 7 h postfeeding for PM compared with C or GS diets on d 83. Pearl millet grain may be used as a feed grain for beef cattle, but diets should be formulated to efficiently utilize the high quantity of protein (about 14% of DM) in this grain as a substitute for supplemental protein.

Summary 1.Illumination of just the telson (tail) of the horseshoe crab with visible light shifted the phase of the circadian rhythm of the median ocellar or lateral eye ERG amplitudes.2.Preventing illumination from reaching the telson reduced or eliminated the phase shift produced by general illumination. We conclude that the telson contains circadian photoreceptors for the central clock controlling the visual rhythms.3.Illuminating parts of the telson also shifted the phase of the ERG rhythm, indicating that the photoreceptors are distributed along the telson.4.The phase response to illumination of the telson alone resembled that produced by general illumination of the whole animal, with delays occurring in the first half of subjective night, and advances in the second half.5.Illumination of the telson also transiently depressed the lateral eye ERG. This effect was observable within 20 min of the beginning of illumination, indicating that the photoreceptors in the telson have an immediate effect on the efferent optic-nerve signals from the clock to the lateral eye.

Summary Congenital heart disease occurs in about 50% of patients with Noonan's syndrome. We report the unusual association of stenotic dysplastic pulmonary valve, peripheral pulmonary stenosis, right aortic arch, aberrant left subclavian artery, and complex aortic coarctation in a 9-year-old boy with Noonan's syndrome.

Abstract:  Apomixis has never been reported in natural populations of pearl millet [Pennisetum glaucum (L.) R.Br.], although many wild relatives of pearl millet are obligate or facultative aposporous apomicts. Four-nucleate aposporous embryo sacs are formed from somatic cells of the nucellus that do not undergo meiosis. Two mutants of pearl millet, female sterile (fs) and stubby head, have two developmental characteristics in common: a significant reduction in head length compared with the wild-type and the formation of aposporous embryo sacs. Reproductive development in fs and stubby head mutants was examined in depth because of the potential for illuminating basic cellular or developmental factors that may function to alter embryo sac development. Genetic analysis of stubby head showed that this phenotype is conferred by genes at two loci linked in coupling within 29 cM. Crosses between fs and stubby head mutants showed that, despite the similarities in phenotypes, the mutations are at different loci. The mutants differ from wild-type in their inflorescence structure from the time of initiation of spikelet primordia through terminal differentiation of the ovule. Both mutations could be categorized as meristic, since a change in inflorescence branch or organ number was common and gynoecium development varied. We speculate that heterochronic development of the floral meristem and organ initiation/specification programs may be the underlying mechanism for phenotypic changes in these mutants throughout the floral phase.

Shortage of nutritious forage is limiting animal production in the semiarid regions of Africa. This study was conducted to evaluate the magnitude of heterosis for forage production and dry matter digestibility in African landraces of pearl millet [Pennisetum glaucum(L.) R. Br.]. Five landrace populations, 9 of 10 interpopulation crosses, and two hybrids were evaluated in a randomized complete‐block design with five replications for dry matter forage yield and in vitro dry matter digestibility (IVDMD) in 1989 and 1990 in Tifton, GA. Entries in only two replications were evaluated for digestibility. The missing cross was estimated, and both the traditional and Gardner‐Eberhart analyses were performed. Highly significant difference between crosses (9.94 t ha−1) and parents (8.50 t ha−1), or average heterosis, well as general combining ability was observed in the combined analyses for dry weight forage yield. No other partitions of entries for either trait were significant. Year × entries was significant for forage yield but not for IVDMD. All midparent and high‐parent heterosis values were positive for forage yield but were nonsignificant. High‐parent heterosis values ranged from 3.3 (‘Iniari’ × ‘Mansori’) to 22.9% (Iniari × ‘P3Kolo’) for dry matter forage yield. No heterosis was observed for IVDMD. Heterosis for forage yield did not affect IVDMD. These results suggest that use of pearl millet hybrids can contribute to increased forage production in semiarid Africa.

A glaciated first‐order valley in south central New York was studied to determine the post‐glacial evolution of the landforms. Ninety‐seven profiles were sampled at depth intervals of approximately 30 cm to determine internal features of the landscape units. Particle size differences were the main indicators of lithologic discontinuities. Arithmetic mean of the fine earth particle size in conjunction with the relative amounts and orientation of coarse fragments were useful in determining strata of the summit, shoulder, backslope, footslope, toeslope and the high, intermediate, and low level terraces. Congeliturbate as much as 10 m deep was found in the basin at the head of the stream in foot‐ and toeslope areas. The downstream portion of these deposits has been deeply entrenched by the stream. During periglacial times congeliturbate in the downstream channel contributed to temporary base levels of the stream. Much of this congeliturbate remains as terraces. The alluvium resulting from the entrenchment of the congeliturbate occurs as a series of 92 terrace remnants and it is believed that their strata, relative elevation, and gradient contain clues to the complex sequence of erosional and depositional events.

Morphologically the soils in Hemlock Creek watershed are related to geomorphic development since glaciation. Initial drift deposits covering the 75‐ha area in south‐central New York were modified by mass movement (solifluction) and then altered by fluvial aggradation‐degradation under a periglacial environment, and by erosion in more recent times. Eight soil profiles representative of the geomorphic components forming the watershed were evaluated. Fragiochrepts dominate the shoulder, backslope, and upper footslope components. They are also the major soils on congeliturbate terraces and on step‐treads of the upper basin. Fragiaquepts are common on the lower footslope and toeslope components and also occur on portions of the step‐treads of the cirque‐like basin. Fragipans have formed in both glacial till and congeliturbate deposits indicating a pedologic origin. Structural expression and density of the pans increase with a decrease in natural drainage in both deposits. Dystrochrepts are dominant soils on the summit and on the intermediate level fluvial terraces; Entisols occur on the low level alluvial terraces. Pan formation is thought to be precluded by nearness of bedrock (< 1 m) to the surface in the summit area and by matrix textures in the fluvial terraces. Stratigraphic changes that produce distinct discontinuities in fluvial terrace profiles are readily evident. Incipient stratification in congeliturbate deposits appears to affect soil morphology, especially horizon thickness, in these relatively young soils.

Techniques are needed to rapidly assess the location of phenotics within cell types. The objective of this work was to investigate by midinfrared microspectroscopy a series of intact cell types, which have a range of digestibilities, from normal (N) and brown midrib (bmr) pearl millet [Pennisetum glaucum(L) R. Br.]. Rind and parenchyma tissues were evaluated using a Nicolet System 740 spectrometer equipped with a Nicolet 0.25 mm MCT‐A detector1interfaced to a microscope. Spectra of rind were similar for normal and bmr mutants and closely resembled lignin spectra. Spectra of pith tissue were similar among plant types and to that for carbohydrates, but differed from rind spectra. Preliminary results indicated that spectra were different for tissues of different digestibilities and showed promise for the use of microspectroscopy in evaluating forage quality of cell types.

Desmopressin (DDAVP) has been used both prophylactically and therapeutically in the management of excessive bleeding after cardiopulmonary bypass. A series of four consecutive cases is presented in which DDAVP was used to treat excessive bleeding, associated with aspirin antiplatelet therapy in three cases and after all other measures had failed in one. The therapeutic use of DDAVP in aspirin‐related bleeding after bypass has not been reported previously. There was no measured haemodynamic effect of the regimen used. Bleeding ceased promptly after administration of DDAVP in all cases. No morbidity was observed in any of the patients. The indications for use of DDAVP and postulated mechanisms of action are discussed.