Blackthorn Research Articles

Evolution of Antimicrobial, Antioxidant Potentials and Phytochemical Studies of Three Solvent Extracts of Five Species from <i>Acacia</i> Used in Sudanese Ethnomedicine

The ethanol, chloroform and acetone extracts of five species from Acacia (Acacia albidia stems, Acacia mellifera aerial parts, Acacia nubica aerial parts, Acacia seyal var. seyal stems and Acacia tortilis aerial parts) were investigated for their antimicrobial activity against two standard bacterial strains of Gram +ve bacteria (Staphylococcus aureus (ATCC 25923)), Gram -ve bacteria (Pseudomonas aeruginosa (ATCC 27853)) and standard fungi Candida albicans (ATCC 90028) using the agar-plate well diffusion method. The chloroform extract was inactive compared to ethanol and acetone extracts. But ethanol extracts showed the maximum antimicrobial activity against the test organism. Amongst the plant species screened, ethanol extract of Acacia seyal stems showed maximum inhibitory activity (38 mm) and (37 mm) against Staphylococcus aureus and Candida albicans, respectively. The ethanol, chloroform and acetone extracts of Acacia mellifera (aerial parts) did not show any activity against the test organisms. Cholorophorm and acetone extracts via DPPH, the radical scavenging activities were found to be 91 ± 0.03, 88 ± 0.01 and 85 ± 0.04, respectively. The results of phytochemical screening showed that all extracts of studied plant contain flavonoids, saponins, terpenoids, steroids, alkaloids, phenols and tannins.

A Chemotaxonomic Approach to the Fatty Acid Content of Some Acacia Taxa from Central Sudan

The aim of the present study was to evaluate the composition of fatty acids of mature seeds of some Acacia taxa (Acacia mellifera, A. nilotica ssp. adansonia, A. nilotica ssp. nilotica, A. oerfota, A. polycantha ssp. campylacantha, A. enegal var. senegal, ...

In vitro methane and gas production characteristics of Eragrostis trichopophora substrate supplemented with different browse foliage

An in vitro gas production study was conducted to evaluate the potential of six browse species (high, medium and low condensed tannin concentrations) collected from the Kalahari Desert as antimethanogenic additives to an Eragrostis trichopophora-based substrate. The browse species studied were Acacia luederitzii, Monechma incanum, Acacia erioloba, Acacia haematoxylon, Olea europaea and Acacia mellifera. The edible forage dry matter of the browse species were incubated with Eragrostis trichopophora in a 30 : 70 (w/w) ratio by adding 40 mL of a buffered rumen fluid at 39°C for 48 h. Gas and methane production at different time intervals after incubation were determined whereas the volatile fatty acids concentration was evaluated after 48 h. Acacia luederitzii and M. incanum foliage decreased methane production by more than 50%, but simultaneously decreased digestibility, and rumen fermentation parameters such as volatile fatty acids concentration. Tannin extracts from A. luederitzii could possibly be used as a dietary alternative to reduce methane production; however, there is a need to determine an optimum level of inclusion that may not compromise the efficiency of rumen fermentation and overall digestibility of the diet.

Influence of fire on woody vegetation density, cover and structure at Tiisa Kalahari Ranch in western Botswana

AbstractWoody vegetation assessments were conducted in the burned and unburned paddocks of Tiisa Kalahari Ranch in western Botswana to determine the influence of opportunistic burning on woody species density, cover and structure in semiarid rangelands. Burning was conducted by farm management twice in one paddock in October 2005 and 2006, and once in another paddock in October 2011 to control bush encroachment. Sampling was conducted in May 2012 using 50 by 2 m transects (16 at the 2011 burn site and 18 at the 2005/2006 burn site) as paired comparisons in both burned and unburned paddocks. Tree height was 0.27 m (28%) and 0.23 m (21%) lower (P < 0.05) in burned paddocks at the 2011 and 2005/2006 burn sites, respectively. There was an increase in the proportion of saplings and a decrease in tall woody plants in burned areas at all sites (P < 0.001). At the 2011 burn site, height and cover of Catophractes alexandri were 63% (P = 0.041) and 67% (P = 0.035) lower in burned paddocks, respectively. Density of Acacia mellifera was 53% (P = 0.031) lower, with more multi‐stemmed (>20 stems) plants in burned paddocks (P = 0.02). Grewia flava density was 59% higher in burned paddocks (P = 0.038). At the 2005/2006 burn site both height and density of Acacia hebeclada were significantly higher in burned paddocks (65%, P = 0.045 and 56%, P = 0.037, respectively). Tarchonanthus camphoratus was only present at this site, where its height, density and cover were significantly lower in burned paddocks (P < 0.05). Overall, tree height was shorter in burned than unburned paddocks, with C. alexandri contributing the most to the height reduction. Follow up browsing by goats on the coppice growth after burning may prevent C. alexandri, a dominant encroaching species from recruiting and spreading.

The Blackthorn Key by Kevin Sands (review)

The Blackthorn Key by Kevin Sands (review)

Traditional Glue, Adhesive and Poison Used for Composite Weapons by Ju/'hoan San in Nyae Nyae, Namibia. Implications for the Evolution of Hunting Equipment in Prehistory.

Ju/’hoan hunters from Nyae Nyae, near Tsumkwe in Namibia, demonstrate the manufacture of three fixative pastes made from plant extracts, and poison made from grubs and plant extracts. Ammocharis coranica and Terminalia sericea produce simple glue. Ozoroa schinzii latex mixed with carbonized Aristeda adscensionis grass is a compound adhesive. Composite poison is made from Chrysomelid grub viscera mixed with salivary extracts of Acacia mellifera inner bark and the tuber sap of Asparagus exuvialis. In order to document potential variability in the chaîne opératoire, and to eliminate inherent biases associated with unique observations, we studied manufacturing processes in three separate Nyae Nyae villages. Although there are methodological similarities in the Nyae Nyae area, we observed a few differences in contemporary traditions of poison manufacture. For example, some hunters make powder from Asparagus exuvialis tuber sap by boiling, reducing, hardening and grinding it, while others simply use heated sap. The Ju/’hoan hunting kit provides insights for archaeologists, but we must exercise caution when looking for continuity between prehistoric and historical technical systems. Some traditions have been lost to modern hunters, while others are new. We should also expect variability in the Stone Age because of geographically restricted resources. Simple glue, compound adhesive, and poison recipes identified in the Stone Age have no modern equivalents. By about 60,000 years ago at Diepkloof, simple glue was used for hafting tools, but at similarly-aged Sibudu there are recipes that combine red ochre powder with plant and/or animal ingredients. At Border Cave, novel poisons and compound adhesives were used in the Early Later Stone Age. It is possible that the complexity that we record in the manufacture of fixative pastes and poison used by Ju/’hoan hunters represents a hafting system both similar to and different from that observed at the Stone Age sites of Diepkloof, Sibudu, and Border Cave.

The Effects of Blackthorn (Prunus Spinosa L.) Addition on Certain Quality Characteristics of Ice Cream

AbstractThe aim of this study was to determine the certain physicochemical properties, color values, total phenolic content (TPC) and flavonoid content (TFC), glass transition (Tg′), melting (Tm′), freezing point (Tf) and melting point (Tm) temperatures, and sensory characteristics of ice cream produced with minced blackthorn (BT) (Prunus spinosaL.) at different concentrations. The increment ofBTconcentration caused an increase in the titratable acidity, viscosity, overrun, first dripping and complete melting times anda* color value, while decreasing the total solid, ash, fat, protein contents,pH,L* andb* color values.TPCandTFCvalues of samples showed a variation from 42.22 to 84.85 and from 27.40 to 39.03 μgQE/mg extract, respectively, whereasTg′,Tm′,TfandTmvalues showed a significant decrease with the increment ofBTconcentration. On the sensory evaluation, only color scores of the samples showed differences from each other atP < 0.05 level.Practical ApplicationsIce cream is an important dairy product produced with milk, cream, water, fruits, flavoring agents and other ingredients. The acceptability of the ice cream by consumers is affected by some factors, including quality characteristics, ingredients, sensory properties and storage conditions. In recent years, the use of natural and organic additives such as fruits for ice cream production showed an increase. ThePrunus spinosa L. (blackthorn [BT]) is a natural fruit and locally grows in some parts of the world.BTcontains high amount of antioxidant and polyphenolic compounds, vitamins and minerals. The use ofBTat different concentrations for ice cream production caused an acceptable effect on some physicochemical, thermal and sensory properties of ice cream. On the contrary, the concentration increase ofBTallowed important effects on most of the observed quality parameters of ice cream samples.

A quantitative description of the interspecies diversity of belowground structure in savanna woody plants

The relative importance of resource competition and disturbance in limiting woody cover is one of the most basic questions in savanna ecology. Modeling approaches that seek to address this question are limited in their ability to accurately represent resource competition, which occurs belowground, by the limited detail of existing data on root system structure. Using compressed air, we excavated individual trees and shrubs and mapped their coarse roots on a three‐dimensional grid system up to 1.5 m depth. We excavated four woody savanna species at three sites spanning a climate gradient on the Kalahari Transect in southern Africa and determined functions to describe the distribution of root biomass within the root systems. Overall, most of the variation in both large‐scale and small‐scale characteristics of root system structure was related to species. The species excavated fell into two groups that coexisted across the climate gradient. Acacia mellifera and Terminalia sericea had straight roots in a laterally extensive system that was shallow relative to the aggregate root profile for woody plants at the sites. Boscia albitrunca and Ochna pulchra had sinuous roots that were mostly concentrated beneath the canopy and were more prevalent in deep than near‐surface soil layers, departing from the conventional model of decreasing root abundance with depth. Based on our results, we suggest a reframing of the theoretical characterization of the root zone used in modeling approaches to consider diversity within the woody plant community.

Detecting Trends in Landuse and Landcover Change of Nech Sar National Park, Ethiopia.

Nech Sar National Park (NSNP) is one of the most important biodiversity centers in Ethiopia. In recent years, a widespread decline of the terrestrial ecosystems has been reported, yet to date there is no comprehensive assessment on degradation across the park. In this study, changes in landcover were analyzed using 30m spatial resolution Landsat imagery. Interannual variations of normalized difference vegetation index (NDVI) were examined and compared with climatic variables. The result presented seven landcover classes and five of the seven landcover classes (forest, bush/shrubland, wooded grassland, woodland and grassland) were related to natural vegetation and two landcover types (cultivated land and area under encroaching plants) were direct results of anthropogenic alterations of the landscape. The forest, grassland, and wooded grassland are the most threatened habitat types. A considerable area of the grassland has been replaced by encroaching plants, prominently by Dichrostachys cinerea, Acacia mellifera, A. nilotica, A. oerfota, and A. seyal and is greatly affected by expansion of herbaceous plants, most commonly the species of the family Malvaceae which include Abutilon anglosomaliae, A.bidentatum and A.figarianu. Thus, changes in vegetation of NSNP may be attributed to (i) degradation of existing vegetation through deforestation and (ii) replacement of existing vegetation by encroaching plants. While limited in local meteorological station, NDVI analysis indicated that climate related changes did not have major effects on park vegetation degradation, which suggests anthropogenic impacts as a major driver of observed disturbances.

Some ecological side-effects of chemical and physical bush clearing in a southern African rangeland ecosystem

Bush thickening is a major concern to farmers of arid and semi-arid rangelands; reactive intervention remains the norm. Here we compared some of the short-term ecological implications of chemical and physical removal of the bush encroacher Acacia mellifera in the central Highland savanna of Namibia. We selected 21 invaded sites, 7 had been chemically cleared, 7 had been physically cleared and 7 had never been cleared. From each site, we recorded grass species composition, as well as the densities of A. mellifera, the undesired perennial shrub Pechuel-loeschea leubnitziae and a non-targeted tree Acacia erioloba, 24–30months post-treatment. We fitted one-way ANOVA models to test for the effect of treatment on grass species richness and density of targeted and non-targeted tree species. A canonical correspondence analysis was used to determine how treatment affected grass species composition. While both treatments reduced the density of the bush encroacher, P. leubnitziae effectively replaced A. mellifera in chemically treated sites, where die-back presumably happened faster and nutrient and water competition decreased more rapidly. In such sites, perennial grass species were effectively outcompeted by P. leubnitiziae.

P055: Hepatoprotective and anti‐viral efficacy of Acacia mellifera leaves ethanolic‐fractions against hepatitis B virus (HBV)

P055: Hepatoprotective and anti‐viral efficacy of Acacia mellifera leaves ethanolic‐fractions against hepatitis B virus (HBV)

Infestation of Quadrastichus erythrinae Kim (Eulopidae: Hymenoptera) an invasive pest on Erythrina spp, a popular standard for black pepper (Piper nigrum) in Idukki district in Kerala, India

Black pepper is an important spice crop grown in Kerala state. Idukki and Wayanad districts contribute major share in production of this spice crop. More than 80 percent of pepper vines grown in this area are trailed on Erythrina spp. A survey has been conducted to ascertain the severity of gall wasp infestation in Erythrina spp. The total number of locations and black pepper gardens covered during the survey include 6 blocks and 37 panchyats in Idukki district of Kerala state. E. variegata (dense thorn) could be rated as moderately resistant (Scale 2- 25% infestation and less) and E. variegata (white thorn) as less susceptible (Scale 3 - 25 to 50 % infestation). The reaction of different types/species of Erythrina to EWG has revealed that the infestation was higher in black thorn type of E. variegata where in the infestation was 75 to 100 percent. Chakkupallam, Erattayar, Kanchiyar of Kattappana panchayats recorded maximum infestation since the pepper growers used black thorned type of E. variegata as standards.

Hepatoprotective and antiviral efficacy of Acacia mellifera leaves fractions against hepatitis B virus.

The present study investigated the hepatoprotective and anti-HBV efficacy of Acacia mellifera (AM) leaves extracts. The crude ethanolic-extract, including organic and aqueous fractions, were tested for cytotoxicity on HepG2 and HepG2.2.15 cells (IC50 = 684 μg/mL). Of these, the ethyl acetate and aqueous fractions showed the most promising, dose-dependent hepatoprotection in DCFH-toxicated cells at 48 h. In CCl4-injured rats, oral administration of AM ethanol extract (250 and 500 mg/kg·bw) for three weeks significantly normalized the sera aminotransferases, alkaline phosphatase, bilirubin, cholesterol, triglycerides, and lipoprotein levels and elevated tissue nonprotein sulphydryl and total protein. The histopathology of dissected livers also revealed that AM cured the tissue lesions. The phytochemical screening of the fractions showed presence of alkaloids, flavonoids, tannins, sterols, and saponins. Further, anti-HBV potential of the fractions was evaluated on HepG2.2.15 cells. Of these, the n-butanol and aqueous fractions exhibited the best inhibitory effects on HBsAg and HBeAg expressions in dose- and time-dependent manner. Taken together, while the ethyl acetate and aqueous fractions exhibited the most promising antioxidant/hepatoprotective and anti-HBV activity, respectively, the n-butanol partition showed both activities. Therefore, the therapeutic potential of AM extracts warrants further isolation of the active principle(s) and its phytochemical as well as biological studies.

Stand Structure, Diversity and Regeneration Status of Woody Species in Open and Exclosed Dry Woodland Sites around <i>Molapo</i> Farming Areas of the Okavango Delta, Northeastern Botswana

Stand structure, diversity and regeneration status of woody species were investigated in open and exclosed dry woodland sites in Island Safari, Shorobe and Xobe, northeastern Botswana. A total of 105, 111 and 130 quadrats, measuring 20 × 20 m each, were laid down along parallel line transects in the three sites, respectively, to collect data. A total of 47 species, representing 16 families and 24 genera, were recorded in the study sites. Of these, 33 species representing 13 families and 20 genera, 41 species representing 15 families and 23 genera and 27 species representing 10 families and 14 genera were encountered in Island Safari, Shorobe and Xobe, respectively. The most diverse family was Fabaceae followed by Combretaceae and Tiliaceae at all the three sites. The most diverse genus was Acacia, followed by Combretum and Grewia. The diversity of woody species in the study sites were 2.18, 2.15 and 1.5 in Shorobe, Island Safari and Xobe, respectively, while their corresponding evenness values were 0.6, 0.6 and 0.5, respectively. The mean densities of the woody species encountered in Island Safari, Shorobe and Xobe were 2629, 4271 and 2745 individuals ha&#451, respectively. The five densest species were Colophospermum mopane, Dichrostachys cinerea, Acacia tortilis, Philenoptera violacea and Terminalia prunioides in Island Safari, C. mopane, A. tortilis, A. erioloba, P. violacea and D. cinerea in Shorobe and Acacia mellifera, A. tortilis, P. nelsii, A. luederitzii and A. erubescens in Xobe. The highest important value index values were exhibited by C. mopane, D. cinerea, A. tortilis, P. violacea and T. prunioides in Island Safari, C. mopane, A. erioloba, A. tortilis, P. violacea and C. imberbe in Shorobe, and A. mellifera, A. tortilis, P. nelsii and A. luederitzii in Xobe. The alarming result was the fact that 71%, 80% and 85% of the woody species recorded in Island Safari, Shorobe and Xobe, respectively, exhibited hampered regeneration and, thus, unhealthy population structures. Therefore, there is an urgent need to address the observed unhealthy population structures of the woody species through investigation of the major causes of their hampered regeneration, and also designing measures that will facilitate natural and artificial regeneration of these species at the three study sites.

Arthur of the Northeast: The Old Swedish Herr Ivan Redraws the King Arthur of Chrétien’s Yvain

In the last half-decade, scholars have begun update long-held, mostly unfavorable opinions about the literary qualities and cultural importance of the group of three early fourteenth-century Old Swedish verse-romances collectively known scholars as the Eufemiavisor, after their likely patron, the German-born Queen Eufemia of Norway (r. 1299-1312). For its part, the 1303 Herr Ivan--a full-length verse translation of Chretien de Troyes's Arthurian masterpiece Yvain, ou le Chevalier au Lion, and probably the first of the Eufemiavisor be written--has long been disparaged as rather mediocre, unambitious romance that is sometimes bereft of sparkle (Layher 2011, 140) and which neither captures the thematic and rhetorical nuances of its primary source, Yvain, nor succeeds in creating any unifying thematic or ideological programs of its own.1 The important conclusions of Sofia Loden's 2012 Stockholm University dissertation on Herr Ivan serve as an overdue corrective such views, and are emblematic of rapidly shifting scholarly attitudes. As she observes, Herr Ivan is a coherent and engaged interpretation that does not misinterpret its sources but interprets them for the sake of intrinsic coherence (Loden 2012, 285), and romance that succeeds in its program to present set of ideological and aesthetic values (284) the high-ranking Swedish aristocracy that made up its target audience. (2) Among the central thematic features of the Old Swedish text is its program presenting model political behaviors suitable for emulation by noble audience members. In fact, the Old Swedish text delivers much more coherent and positive picture of right rule and the ideal relationships that should exist between individuals sharing political bonds than had Chretien's often morally and politically ambiguous Yrain. (3) While in Herr Ivan, such ideal political conduct manifests itself most visibly in the interactions among the text's most central characters--that is, the hero, Ivan, his wife, Laudine, and her chief lady-in-waiting, Lunete--this essay will focus on figure who occupies relatively little narrative space in the tale, namely King Arthur. But while Arthur's appearances are quite limited, just as they are in the vast majority of Arthurian romances from medieval Europe that took their generic inspiration from the Arthurian narratives of Chretien de Troyes, these appearances are not insignificant the overall fabric of the story. Indeed, in Herr Ivan and Train, as in most other Arthurian romances, Arthur serves as the benchmark against whom other kings and rulers are judged, as the courtly and martial norm against whom other knights are evaluated, and as the standard against whom other husbands in political marriages are viewed. As this essay will demonstrate, the Herr Ivan poet skillfully and consequently redraws the much-less-than-perfect Arthur of Chretien's Yvain create more perfect Arthur who embodies the qualities of an ideal king and feudal lord. In so doing, the Herr Ivan poet fashions with his northeastern King Arthur character who is in harmony with his translation's larger thematic agenda extolling life at court and the political and social relationships that obtain there. To determine how the Old Swedish poet transforms the Arthur of Chretien's Yvain, this essay will consider Arthur's performance in several key appearances. These include: his retreat the bedchamber during Pentecost festivities at his court; his role in convincing the hero ride with the Round Table knights for year in tournaments; his behavior at Ivan/Yvain's temporary tent-court prior the hero's descent into madness in the forest; and his activities as judge in the Black Thorn inheritance dispute. But first, let us turn very beginning of the tale, the prologue, where the first mention of Arthur is made. THE HERR IVAN PROLOGUE: ESTABLISHING ARTHUR AS AN EXEMPLARY FIGURE Immediately in those opening lines of the story that function as kind of prologue in both the Old French original and the Old Swedish translation, Herr Ivan begins its presentation of much more clearly defined Arthur than the one who emerges early on in Yvain. …

Control of bush encroachment in Borana zone of southern Ethiopia: effects of different control techniques on rangeland vegetation and tick populations

A study on effects of bush encroachment control techniques on rangeland productivity and tick population dynamics was conducted in Arero district of Borana zone, southern Ethiopia, for three consecutive years. The study targeted two main and dominant encroaching bush species in Borana rangeland, Acacia drepanolobium and Acacia mellifera, and their effects on some vegetation attributes and tick population dynamics. A hectare of rangeland encroached by these two acacia species was replicated/divided into three plots, and each plot was subdivided into five sub-plots to receive five treatments: cutting at 0.5 m above ground and pouring kerosene on stumps (T1), cutting at 0.5 m above ground and debarking the stumps down into the soil surface (T2), cutting at 0.5 m above ground alone (T3), cutting at 0.5 m above ground and dissecting the stumps (T4) and control (T5). Data on basal and litter covers, soil erosion and compaction, dead and re-sprouted encroaching tree/shrub species and nymph- and adult-stage tick populations were collected before and after treatment applications. The applied treatments significantly influenced (p < 0.05) basal cover, nymph- and adult-stage tick population and the two encroaching tree species. The results of this study showed that T3 and T2 were good in controlling A. drepanolobium in that order. T4 and T2 had a significant effect in controlling A. mellifera in their order. Controlling bush encroachment had also a positive effect in eradicating the tick population. The most dominant grass and non-grass species observed after the control actions were Cenchrus ciliaris, Chrysopogon aucheri, Abutilon hirtum, Pennisetum mezianum, Dyschoriste hildebrandtii, Zaleya pentandra and Eragrostis papposa. Therefore, controlling encroaching tree/shrub species had created a conducive grazing area with palatable herbaceous species for the livestock and unequivocally reduced tick population which play a role in reducing cattle milk production through closing off teats. The management of bush encroachment, if sustained, will contribute in stabilizing rangelands and help minimize the negative effects of feed and food crises in the future.

Persistent Effects of Chemicals Used to Control Shrub Densification in Semi-Arid Savanna

Mokala National Park (MoNP) was proclaimed in 2007 in an area that used to be managed as a commercial wildlife and hunting farm, and prior to 2003 as a cattle and goat farm. The vegetation comprises sparse to closed woodlands and shrublands of the Savanna Biome. Shrub densification was deemed undesirable in the context of commercial farming where management objectives were to maximise production of grazing animals and to promote visibility of wildlife to tourists and hunters. Accordingly, previous landowners have attempted to eradicate prolific shrubs (particularly Senegalia mellifera) by mechanical and chemical means in certain areas during the period 1996–2004. Effects of these treatments are still apparent more than a decade later. Here we document the history of herbicide applications and other management practices in affected areas of MoNP. We furthermore explore potential ecological effects of the herbicide used (‘Molopo 200GG’ with active ingredient Tebuthiuron) in relation to the ecology of the most-affected shrub species, S. mellifera. We conclude with suggestions for future monitoring to establish potential long-term impacts of the chemical control.

Riparian trees as common denominators across the river flow spectrum: are ecophysiological methods useful tools in environmental flow assessments?

Riparian tree species, growing under different conditions of water availability, can adapt their physiology to maximise their survival chances. Rivers in South Africa may flow perennially, seasonally or ephemerally (episodically). Different riparian species are adapted to survive under each of these different flow regimes by making use of surface, ground, soil, rainwater, or some combination of these. These water sources are available to varying degrees, depending on local climatic, hydrological, geohydrological and geomorphological conditions. This paper tests physiological differences among trees along rivers with varying flow regimes. In this study 3 parameters were selected and tested, namely wood density, specific leaf area and water use efficiency through stable carbon isotope measurements. All three parameters are quick, simple and cheap to determine and as such their value for standard-procedure river monitoring programmes or environmental flow requirement procedures was tested. Acacia erioloba is an arid-adapted riparian tree along the ephemeral Kuiseb (Namibia) and Kuruman (South Africa) Rivers that shows decreasing specific leaf area and increasing wood density correlating with deeper groundwater levels. Intraspecific changes for specific leaf area and carbon isotope values were demonstrated for Acacia mellifera and Croton gratissimus at varying distances from the active channel of the seasonal Mokolo River (South Africa). No significant differences in physiology were noted for Salix mucronata, Brabejum stellatifolium and Metrosideros angustifolia, growing along the perennial Molenaars and Sanddrifskloof Rivers (South Africa) under reduced flow conditions. Only the measurement of specific leaf area recurrently showed that significant physiological differences for trees occurred along rivers of the drier flow regime spectrum (seasonal and ephemeral). As such, this physiological measurement may be a valuable indicator for water stress, while the other measurements might provide more conclusive results if a larger sampling size were used. Specific leaf area, in conjunction with other carefully picked water stress measurement methods, could be considered for monitoring programmes during environmental flow assessments, river health monitoring exercises and restoration projects. This would be particularly valuable in rivers without permanent flow, where there is little species-specific knowledge and where current monitoring methods are unsuited.Keywords: ecophysiology, stable δ13C isotopes, wood density, specific leaf area, EFAs, river flow regimes, trees

Buserelin acetate-induced spermiation in Leptodactylus ocellatus and evaluation of semen characteristics

By understanding the hormonal action behind the induction of spermiation in Leptodactylus ocellatus can help in the collection of semen for artificial insemination and cryopreservation. The experiments were conducted at the Experimental Frog Farm of the Federal University of Vicosa. Seven L. ocellatus males with the following secondary sexual characteristics were selected: black thorns, developed forelimbs, and amplexus reflex. Spermiation was induced in these animals by applying daily 0.4 μg buserelin acetate hormone (GnRHa) for 7 days, being the semen collected 90 min after the application. The volume, color, vigor, motility, sperm concentration, and spermatozoa morphology were subsequently evaluated. Three animals responded to GnRHa induction, enabling the collection of seven samples of semen, and the first sample was collected 97.5h after the first application. The semen of the creole frog presented the following characteristics: an average volume of 0.38 mL, murky color, sperm vigor of 3.71, sperm motility of 77.14%, sperm concentration of 6.60 x 10 6 SPTZ mL -1 , and 69% of normal sperm. GnRHa can induce spermiation in the creole frog. Although the volume of collected semen was low, the color, vigor, motility, concentration, and spermatozoa content showed to be adequate.

The new curses of tomb space

Abstract In the 1980s, the United States Department of Energy created The Human Interference Task Force, a group of semioticians, physicists, science-fiction writers and anthropologists tasked with creating an everlasting warning to prevent future beings from unintentionally disturbing nuclear waste repositories. The proposed systems ranged from warning orbital satellites to glowing radioactive cat companions, to setting up an atomic priest hood, to surrounding the site with giant black thorns. These paranoic strategies of radical closure can be further examined in comparison and contradiction to the openness of the Sudbury Neutrino Observatory in which massive quantities of pure water are housed in order to detect the passage of weakly interacting neutrinos. This site of inviting invasion is at the same time isolated and buried deep in the earth. These two examples demonstrate that the attempt to combat and the attempt to welcome contingency involve complex and twisted modes of closure and openness as demonstrated by the work of Reza Negarestani. By investigating these models, I hope to investigate how the intimacies of geological formation cross into and disrupt the purported stability of space (both as outer space and abstract space) in relation to chemistry, both inorganic and astrobiological.