4,520 research outputs found
g-Elements, finite buildings and higher Cohen–Macaulay connectivity
No full textAbstractChari proved that if Δ is a (d−1)-dimensional simplicial complex with a convex ear decomposition, then h0⩽⋯⩽h⌊d/2⌋ [M.K. Chari, Two decompositions in topological combinatorics with applications to matroid complexes, Trans. Amer. Math. Soc. 349 (1997) 3925–3943]. Nyman and Swartz raised the problem of whether or not the corresponding g-vector is an M-vector [K. Nyman, E. Swartz, Inequalities for h- and flag h-vectors of geometric lattices, Discrete Comput. Geom. 32 (2004) 533–548]. This is proved to be true by showing that the set of pairs (ω,Θ), where Θ is a l.s.o.p. for k[Δ], the face ring of Δ, and ω is a g-element for k[Δ]/Θ, is nonempty whenever the characteristic of k is zero.Finite buildings have a convex ear decomposition. These decompositions point to inequalities on the flag h-vector of such spaces similar in spirit to those examined in [K. Nyman, E. Swartz, Inequalities for h- and flag h-vectors of geometric lattices, Discrete Comput. Geom. 32 (2004) 533–548] for order complexes of geometric lattices. This also leads to connections between higher Cohen–Macaulay connectivity and conditions which insure that h0<⋯<hi for a predetermined i
Burn trauma in skeletal muscle results in oxidative stress as assessed by in vivo electron paramagnetic resonance
No full textUsing a mouse model, we tested the hypotheses that severe burn trauma causes metabolic disturbances in skeletal muscle, and that these can be measured and repeatedly followed by in vivo electron paramagnetic resonance (EPR). We used a 1.2-GHz (L-band) EPR spectrometer to measure partial pressure of oxygen (pO2) levels, redox status and oxidative stress following a non-lethal burn trauma model to the left hind limbs of mice. Results obtained in the burned mouse gastrocnemius muscle indicated a significant decrease in tissue pO2 immediately (P=0.032) and at 6 h post burn (P=0.004), compared to the gastrocnemius of the unburned hind limb. The redox status of the skeletal muscle also peaked at 6 h post burn (P=0.027) in burned mice. In addition, there was an increase in the EPR signal of the nitroxide produced by oxidation of the hydroxylamine (CP-H) probe at 12 h post burn injury, indicating
a burn-induced increase in mitochondrial reactive oxygen
species (ROS). The nitroxide signal continued to increase
between 12 and 24 h, suggesting a further increase in ROS generation post burn. These results confirm genomic results, which
indicate a downregulation of antioxidant genes and therefore
strongly suggest the dysfunction of the mitochondrial oxidative
system. We believe that the direct measurement of tissue
parameters such as pO2, redox and ROS by EPR may be used
to complement measurements by nuclear magnetic resonance
(NMR) in order to assess tissue damage and the therapeutic
effectiveness of antioxidant agents in severe burn trauma
STUDIES ON HUMAN UTERINE CERVIX AND RAT UTERUS USING S-BAND, X-BAND AND Q-BAND ELECTRON-SPIN-RESONANCE SPECTROSCOPY
No full textIn previous studies we have reported on the detection of a strong e.s.r. signal in samples of normal human cervix; the signal is much reduced or absent in samples of invasive cancer of the cervix. In order to identify the species responsible for the strong signal, we have used X-, S- and Q-band e.s.r. spectroscopy. The major signal that is detectable in ground-up samples of cervix preserved at -196 degrees C has features consistent with the presence of a peroxy free radical. Good agreement with the experimental findings was obtained by computer simulation, using values for the g-tensor of gx = 2.002, gy = 2.005 and gz = 2.036. The peroxy radical is produced on grinding the normal cervix samples to a powder under liquid N2, and appears to be formed by modification of a pre-existing oxygen-containing complex. Control experiments eliminated the possibility that the strong signals seen in frozen powders prepared from normal cervix were artefacts only of the grinding procedure. Experiments with rats in vivo and with cervix samples in vitro are consistent with the conclusion that the peroxy radical is formed by disturbing the cyclo-oxygenase system that is involved in prostaglandin synthesis
Metabolism of aqueous soluble nitroxides in hepatocytes: effects of cell integrity, oxygen, and structure of nitroxides
No full textThe optimum use of nitroxides in viable biological systems, including live animals, requires knowledge of the metabolism of nitroxides by major organ systems, especially the liver. We report here details of the metabolism of several prototypic aqueous soluble nitroxides in suspensions of freshly isolated hepatocytes. The general patterns of metabolism were similar to those observed in other types of cells (previous studies have been done principally in cells from tissue culture, such as CHO cells) including the primary initial reaction being reduction to the hydroxylamine, an increased rate of metabolism of some nitroxides in hypoxic cells, faster rates of reduction of nitroxides on six-membered piperidine rings compared to five-membered pyrrolidine rings, and most metabolism being intracellular. Metabolism in hepatocytes differed from other cell lines in having (1) significant reduction in the extracellular medium due to ascorbate that was released from damaged hepatocytes; (2) decreased rates of metabolism in freeze-thawed cells due to damage to subcellular organelles. These results provide much of the data needed to understand the role of the liver in the metabolism of nitroxides by intact animals and explain some previously puzzling results which indicated an apparent unusually high rate of metabolism of a charged nitroxide (Cat1) by hepatocytes. Our results also indicate that the use of freshly isolated cells or tissue homogenates may introduce experimental artifacts in the study of the metabolism of nitroxide
Discovery of an optical counterpart to the hyperluminous X-ray source in ESO 243-49
No full textThe existence of black holes of masses similar to 10(2)-10(5)M(circle dot) has important implications for the formation and evolution of star clusters and supermassive black holes. One of the strongest candidates to date is the hyperluminous X-ray source (HLX1), possibly located in the S0- a galaxy ESO 243-49, but the lack of an identifiable optical counterpart had hampered its interpretation. Using the Magellan telescope, we have discovered an unresolved optical source with R = 23.80 +/- 0.25 mag and V = 24.5 +/- 0.3 mag within HLX1's positional error circle. This implies an average X-ray/optical flux ratio similar to 500. Taking the same distance as ESO 243-49, we obtain an intrinsic brightness M-R = -11.0 +/- 0.3 mag, comparable to that of a massive globular cluster. Alternatively, the optical source is consistent with a main-sequence M star in the Galactic halo (for example an M4.4 star at approximate to 2.5 kpc). We also examined the properties of ESO 243-49 by combining Swift/Ultraviolet/Optical Telescope (UVOT) observations with stellar population modelling. We found that the overall emission is dominated by a similar to 5-Gyr-old stellar population, but the UV emission at approximate to 2000 angstrom is mostly due to ongoing star formation at a rate of similar to 0.03M(circle dot) yr(-1). The UV emission is more intense (at least a 9 sigma enhancement above the mean) north-east of the nucleus, in the same quadrant as HLX1. With the combined optical and X-ray measurements, we put constraints on the nature of HLX1. We rule out a foreground star and a background AGN. Two alternative scenarios are still viable. HLX1 could be an accreting intermediate mass black hole in a star cluster, which may itself be the stripped nucleus of a dwarf galaxy that passed through ESO 243-49, an event which might have caused the current episode of star formation. Or, it could be a neutron star in the Galactic halo, accreting from an M4-M5 donor star
Psidium guineense Swartz 1788
No full text37. Psidium guineense Swartz (1788: 77). Type:—“ Culta in Hispaniola,” “ ex Africa ”. Presumably Swartz s.n. (holotype: S-r-5302). (Fig. 5P) Shrubs 2 m. Twigs sparsely pubescent or pubescent, indumentum brownish-red. Leaves with petioles 0.5–0.7 mm long, densely or sparsely pubescent, channeled; blades elliptic, elliptic-oblong, oblong or oval, 4–13.5 × 1.8–6.8 cm, densely pubescent, the indumentum reddish-brown, chartaceous, discolorous; glands not seen; base cuneate or rounded; apex acute, mucronate or obtuse; midvein adaxially impressed; lateral veins visible, arched, 7 to 10 pairs; intra-marginal vein absent, margin flat. Inflorescence axillary, a solitary flower or dichasium, 1–3 flowers, the axis 0.9–1.2 mm long, pubescent; bracts not seen, caducous before anthesis; pedicels 0.5–0.7 mm long or absent; bracteoles linear, 1 × 1 mm, pubescent, caducous after anthesis; flower buds pyriform, 4–5 × 7–9 mm, constricted above ovary; calyx-lobes completely fused, four to five, opening by irregular tearing, pubescent, ovate, 5 × 3–5 mm, not reflexed, persisting in the fruit; ovary 3–5-locular. Immature fruit globose, ca. 1.1 × 1.4 cm, glabrous, surface marked with glands. Note:— Psidium guineense may be recognized by its densely or sparsely pubescent, elliptic, oblong or oval leaves; the acute, mucronate or obtuse leaf apex; the inflorescence, which is a solitary flower or dichasium; and the completely fused calyx lobes, opening by irregular tearing. Distribution and habitat:— Known from Tropical America, and widely distributed in Brazil (POWO 2020, Flora do Brasil 2020). In Amazonian Maranhão, P. guineense was found growing in flooded forests and along roads. Phenology:— Flowering in January, February and December. Specimens examined:— BRAZIL. Maranhão: Anajatuba, São Bento, 3°15’52” S, 44°37’11” W, 09 February 2008 (fl.), A. Araujo 10 (IAN!). Pameirândia, 2°38’43” S, 44°53’42” W, 28 January 2007 (fl.), C.M. Vieira 87 (IAN!). Turiaçu, Km 6 da BR 106 Maracaçumé-Sta. Helena, fazenda Maracaçumé Agro Industrial Grupo Mesbla, 1°39’48” S, 45°22’18” W, 01 December 1978 (fl.), N. A. Rosa 2819 & H. Vila (NY!). Additional specimens examined:— BRAZIL. Pará: Vigia, 17km southeat of Vigia along road (PA-140) to Belém, 50 m, 0°57’ S, 48°04’59” W, 30 March 1980 (fr.), G. Davidse, N.A. Rosa, C.S. Rosario & M.G. Silva 17655 (US, image).Published as part of Amorim, Gabriela Dos Santos, Barbosa, Maria Regina De Vasconcellos, Jr, Eduardo Bezerra De Almeida & Thomas, William Wayt, 2022, Taxonomic study of Myrtaceae in forest fragments in Amazonian Maranhão, Brazil, pp. 27-60 in Phytotaxa 568 (1) on page 56, DOI: 10.11646/phytotaxa.568.1.3, http://zenodo.org/record/718424
Labeobarbus seeberi
No full textLabeobarbus seeberi (Gilchrist & Thompson, 1913) SOUTH AFRICA: 1 lectotype (185 mm SL), Olifants River, Clanwilliam, Cape Province, ± -31.700000, 18.200000, C.R. Seeber leg. (ex SAM), (NHMUK 1936.8.4.6); 2 paralectotypes (87–97 mm SL), same collecting data (SAIAB 134867); 1 specimen (165 mm SL), Olifants River, Clanwilliam, Cape, ± -31.700000, 18.200000, South African Museum leg. (NHMUK 1936.8.4.4); 5 specimens (1 examined: 188 mm SL), Olifants River, Clanwilliam, Cape Province, ± -31.700000, 18.200000, South African Museum leg. (NHMUK 1937.10.4.1–5; 1 specimen (380 mm SL), Olifants system, Middeldeur River, -32.750000, 19.216700, 20 Mar. 1996, R. Bills leg. (SAIAB 51534); 1 specimen (134 mm SL), Olifants system, Noordhoeks River, ± -32.720833, 19.065556, 22 Dec. 1996, R. Bills, M. da Pinna and D. Naran leg. (SAIAB 54113); 1 specimen (176 mm SL), Olifants system, Noordhoeks River (above road bridge), ± -32.720799, 19.065599, 22 Mar. 1997, M. Marriott and L. Randall leg. (SAIAB 54688); 1 specimen (179 mm SL), Boskloof River (50 m past the drilling site), Olifants system, ± -32.558102, 19.058901, 23 Feb. 1998, R. Bills, D. Naran and E. Swartz leg. (SAIAB 58362); 6 specimens (1 examined: 101 mm SL), Olifants system, Rondegat River, Upper Keurbos Farm, -32.294399, 18.996901, 23 Mar. 2002, R. Bills, M. Cunningham and E. Swartz leg. (SAIAB 65536); 2 specimens (1 examined: 442 mm SL), Olifants system, 15 Oct. 1960, R.A. Jubb leg. (SAIAB 121138); 7 specimens (1 examined: 435 mm SL), Olifants system, Tharahamina farm (Camp site), ± -32.862500, 19.090278, 28 Mar. 1980, G. Gabriels and S. Thorne leg. (SAIAB 126907); 4 specimens (186–273 mm SL), Olifants system, Kobee, Doring River, Boskraal Farm, -31.592778, 19.075833, 23 Nov. 1983, S. Thorne leg. (SAIAB 129144); 1 specimen (260 mm SL), Olifants system, Visgat, ± -33.055000, 19.208056, 17 Feb. 1987, S. Thorne leg. (SAIAB 130760); 8 specimens (1 examined: 354 mm SL), Olifants River, Clanwilliam, ± -32.716700, 19.033300, Mar. 1938, K.H. Barnard and C.W. Thorne leg. (SAIAB 135537); 13 specimens (6 examined: 74– 103 mm SL), Olifants system, Jan Dissels River, Clanwilliam, ± -32.183300, 18.883301, 13 Nov. 1987, L. Oellermann leg. (SAIAB 28404).Published as part of Skelton, Paul H., Swartz, Ernst R. & Vreven, Emmanuel J., 2018, The identity of Barbus capensis Smith, 1841 and the generic status of southern African tetraploid cyprinids (Teleostei, Cyprinidae), pp. 1-29 in European Journal of Taxonomy 410 on page 4, DOI: 10.5852/ejt.2018.410, http://zenodo.org/record/121119
Potensi Pemanfaatan Tumbuhan Paku Diplazium Esculentum Swartz (Studi Kasus) di Distrik Aifat Utara Kabupaten Maybrat Provinsi Papua Barat
No full textThis study aims to measure the productivity of potential utilization of ferns Diplazium esculentum Swartz and analyze the socio-economic characteristics of community members who employed fern Diplazium esculentum Swartz as a source of income and to describe the pattern of utilization and contribution of ferns Diplazium esculentum Swartz for the community members in Kampung Ayawasi, District North Aifat, District of Maybrat, West Papua Province. The method used is the method of lines; census method is less than 100. This study includes ecological aspects, economic aspects i.e. incomes. Other analytical method used is the analysis of the contribution to household income communities. This study found that productivity of potential utilization of ferns Diplazium esculentum Swartz of Village community in Ayawasi Aifat is total revenue of Rp 530 000,00 or (68.86%) in a range of categories is quite effective at 25-75. Income people who use the fern Diplazium esculentum Swartz can be influenced by socio-economic factors are factors respondents' personal characteristics such as age, education and land, as well as how to harvest. The utilization pattern of fern Diplazium esculentum Swartz has contributed to an increase in household income communities. It was proven that members of community who are active in picking, earn greater revenue compared to people who are not actively lower revenue in conducting harvesting ferns
Farm ponds of the eastern Great Plains: Key challenges and opportunities for conserving amphibians in these novel ecosystems
No full textFarm ponds are numerous in the agricultural landscapes of the Eastern Great Plains of the United States. These ponds are constructed to support a variety of functions, including erosion control, cattle grazing, and recreational fishing, but their role in supporting native biodiversity, including amphibians, remains poorly understood. In addition, it is unclear how farm ponds fit into existing frameworks of restoration and conservation. Despite their abundance, there are no large-scale initiatives in place to enhance the biodiversity value of farm ponds in the United States. Emerging frameworks like the novel ecosystems concept could provide a path forward for farm pond conservation, but the concept remains controversial and its applicability largely untested.
Consequently, my goal was to address both the ecological and philosophical aspects of farm ponds as refuges for biodiversity in agricultural landscapes. First, I sought to identify the important biophysical components of amphibian breeding habitat in farm ponds and assess the species-specific effects of cattle and fish presence. I then used a chronosequence approach to determine whether pond renovation, which often occurs when ponds are 35 years old, threatens the development of amphibian habitat. I found that farm ponds support amphibian reproduction, but habitat use varied by species, underscoring the importance of species-specific approaches. In addition, pond renovation threatens the development of pH, pond slope, and emergent vegetation conditions predictive of amphibian breeding. Moving forward, it will be important to develop ecological and conceptual approaches to balance the agricultural and biodiversity values of these sites. By enabling us to explicitly acknowledge the anthropogenic nature of farm ponds without disregarding them as ‘degraded’, the novel ecosystems concept provides a framework for articulating the conservation value of these ecosystems.Submission published under a 24 month embargo labeled 'Closed Access', the embargo will last until 2020-08-01The student, Timothy Swartz, accepted the attached license on 2018-07-10 at 09:20.The student, Timothy Swartz, submitted this Thesis for approval on 2018-07-10 at 09:21.This Thesis was approved for publication on 2018-07-10 at 15:14.DSpace SAF Submission Ingestion Package generated from Vireo submission #12791 on 2018-09-27 at 11:36:31Made available in DSpace on 2018-09-27T16:47:27Z (GMT). No. of bitstreams: 2
SWARTZ-THESIS-2018.pdf: 8836083 bytes, checksum: 70b9b539eb17c86b366238469f70f0e4 (MD5)
LICENSE.txt: 4211 bytes, checksum: 7ab5b80d04d1b44ac42c01eceeaf4630 (MD5)
Previous issue date: 2018-07-10Embargo set by: Seth Robbins for item 107904
Lift date: 2020-09-27T16:47:41Z
Reason: Author requested closed access (OA after 2yrs) in Vireo ETD systemLimited Restriction Lifted for Item 107904 on 2020-09-28T09:15:22Z
- …
