The flocculation of kaolin with polyacrylamides

Flocculation occurs when high molecular mass organic molecules form bridges between particles, causing them to aggregate. This modifies the sedimentation properties of the mineral slurry. Thus classical measures of flocculation, among them the settled bed height and the supernatant turbidity, have tended to focus on the properties of the suspension rather than the flocculant. The kaolin - polyacrylamide system is investigated in this study

Analyzing local people’s opinions on incidences, magnitude and mitigation measures of human-elephant interactions adjacent to the Serengeti National Park

We analysed local people’s opinions to understand their knowledge on the magnitude, incidence, adverse impacts and techniques for minimizing the adverse impacts of human-interactions in the Bunda district. The survey involved 130 local people from 12 villages for survey and interviews. The survey used a purposive sampling technique to locate local people with relevant knowledge on human-elephant interactions occurrences. Researchers are grateful to incorporate local people's opinions into this study because their consolidated knowledge and skills, have for centuries, contributed to undisputed scientific knowledge in environmental conservation. In this study, researchers have learnt that crop damage was the main adverse impacts of human-elephant interactions while house damage was the least recorded incident. Despite crop damage being the most common impact of human-elephant interactions but hidden impacts are the largest adverse impacts. The majority of locals use traditional techniques to prevent and control problem elephants. However, the habituation of elephants to the techniques hinders their effectiveness. A minority of villagers use wounding traps, report to conservation agencies to reduce the damage from elephants. Local people claimed that elephants are docile as it was possible to approach them as close as 50 meters without any harm. Despite their docility, locals also claim that stopping elephants from crop damage may result into human deaths. Villagers acknowledge sighting more than 11 elephants every day in the farming areas. The study recommends the adoption and application of spatial and simulation technologies to identify where, why, how negative impacts of human-elephant interactions. This will suggest the appropriate size of landscape interface of human-elephant interactions in the district

Molecular insights into the biogeography and species status of New Zealand's endemic Latrodectus spider species; L. katipo and L. atritus (Araneae, Theridiidae)

New Zealand's endemic sand dune Latrodectus widow spider species, L. katipo and L. atritus, possess behavioral and physiological attributes likely to promote dispersal over large distances. Morphological, physiological and behavioural similarities between L. katipo and L. hasselti, an Australian endemic, suggest gene flow may occur across the Tasman Sea. In this study we examine intraspecific and interspecific genetic relationships within the ND1 gene region between L. katipo, L. atritus, L. hasselti and L. hesperus to assess whether the genetic evidence supports current taxonomic species designations. We found low interspecific pairwise distances among L. katipo and L. atritus populations, suggesting either introgression, incomplete lineage sorting, or that the current taxonomic distinction between the two species may be invalid. Parsimony and maximum likelihood analyses were inconclusive as to the relationships between the New Zealand Latrodectus species and the Australian L. hasselti. Low pairwise distances between L. hasselti and the New Zealand widow fauna indicated that L. katipo and L. atritus were not present in New Zealand before the fragmentation of Gondwana

The eradication of mammalian predators from Quail Island, Banks Peninsula, Canterbury, New Zealand

In the period from January 2000 to January 2003 an attempt was made to eradicate mammalian pests (rodents, mustelids and hedgehogs) from Quail Island (Otamahua) to allow re-introductions of native species that were once present. Eradication techniques involved live trapping, kill trapping using Fenn traps and night searches that removed a total of 353 individuals. A ground-based poison operation was also undertaken. During 2 - 9 August 2002, 555 bait stations (yellow and black) were placed at 40m intervals covering Quail Island. Stations were baited with Pestoff 20R rodent bait pellets (0.002% brodifacoum) and, at later stages of the operation, Talon 50 WB briquette (0.005% brodifacoum). An analysis of predominant vegetation surrounding stations was also undertaken. Exotic grassland was the dominant habitat where hedgehogs were trapped and found during night searches. Hedgehogs were caught more readily on or near tracks, which they presumably use to feed and travel around the island. Male rats made up 70% of the rat catch. Bait-take by rodents was highest from black bait stations and from scrubland habitats surrounding bait stations on Quail Island. Eradication could not be confirmed, as a few bait stations were still active but most, if not all damage, appears to be by ground (Hemiandrus sp.) and cave weta (Pleioplectron simplex Hutton). Furthermore, a few hedgehog scats have been found since the poison operation began and no hedgehogs have been observed or trapped for 18 months indicating they have become vary scarce or have been eradicated. This information will be important for future management of Quail Island due to the proximity of the mainland, via mudflats, will need ongoing vigilance to protect against pest reinvasion

Establishment of restoration monitoring at Tārerekautuku Yarrs Lagoon: Conservation Biology (ECOL609) project reports

Ninety percent of New Zealand’s wetlands have been lost along with the endemic plants, fish, birds, and invertebrates. Those that remain are threatened by choking weeds, suffocating sediment, pollution from livestock and continued drainage and clearance (Hansford, 2010). Therefore, all remaining wetlands, regardless of their ecological state, are precious and need to be restored and managed to maximise the biodiversity within. Tārerekautuku Yarrs Lagoon is a 76.9 ha reserve located along the Ararira/LII River between Lincoln and Te Waihora/Lake Ellesmere. Tārerekautuku is administered by the Selwyn District Council (SDC) who have recognised the wetland’s intrinsic value. The lagoon area was known as a significant mahinga kai (food gathering) site for Ngāi Tahu, and particularly the local hapū of Ngāi Te Ruahikihiki based at Taumutu. Mahinga kai species being gathered at this site include tuna (eel), koareare (the edible rhizome of raupō/bullrush), koukoupara (bullies), mawehe (kōaro), pārera (grey duck), pūtakitaki (paradise duck), pākura (pukeko), whio (blue duck), kaaha (shag) and aruhe (bracken fern root) (Taiaroa 1880). The cultural and biodiversity values of Tārerekautuku are significant and ecological restoration of the lagoon has a huge potential to enhance these (Boffa Miskell, 2017). Selwyn District Council, with the support of the Department of Conservation (mainly Robin Smith), received approximately $800,000 from Ministry for the Environment ‘Freshwater Improvement Fund’ towards achieving five objectives: 1. To control willows and other weeds across approximately 87 ha in the Tārerekautuku Yarrs Lagoon Wetland. 2. To undertake predator control within the wetland and surrounding catchment to target mustelids, rats, and possums 3. To reduce sediment loads through instream works (up to five sediment traps or equivalent) and waterways re-battering work (approximately 2,000 m), including installing two bridges for site access. 4. To plant at least 12,516 native plants and trees across eight ha of Tārerekautuku wetland and connecting waterways. 5. To establish a monitoring programme at the Tārerekautuku wetland for Mātauranga Māori to measure ecological change over time. With Lincoln University’s proximity and MOU (pending) between them and SDC, this project provides a win-win scenario for students to help monitor ecological changes over time (objective 5). The project summaries that follow are an integral part of the ECOL609 (Conservation Biology) course that is undertaken in the first semester of 2022 where students chose a conservation area to monitor. Vegetation quadrat monitoring intended to replicate Stammer (2010); however, access to the site was deemed unsafe to proceed. This work has been added as an Appendix in this report to allow future comparisons

Globe-hopping

We consider versions of the grasshopper problem (Goulko & Kent 2017 Proc. R. Soc. A473, 20170494) on the circle and the sphere, which are relevant to Bell inequalities. For a circle of circumference 2π, we show that for unconstrained lawns of any length and arbitrary jump lengths, the supremum of the probability for the grasshopper’s jump to stay on the lawn is one. For antipodal lawns, which by definition contain precisely one of each pair of opposite points and have length π, we show this is true except when the jump length ϕ is of the form π(p/q) with p, q coprime and p odd. For these jump lengths, we show the optimal probability is 1 − 1/q and construct optimal lawns. For a pair of antipodal lawns, we show that the optimal probability of jumping from one onto the other is 1 − 1/q for p, q coprime, p odd and q even, and one in all other cases. For an antipodal lawn on the sphere, it is known (Kent & Pitalúa-García 2014 Phys. Rev. A90, 062124) that if ϕ = π/q, where q∈N, then the optimal retention probability of 1 − 1/q for the grasshopper’s jump is provided by a hemispherical lawn. We show that in all other cases where 0 < ϕ < π/2, hemispherical lawns are not optimal, disproving the hemispherical colouring maximality hypotheses (Kent & Pitalúa-García 2014 Phys. Rev. A90, 062124). We discuss the implications for Bell experiments and related cryptographic tests

Reacción en el tamaño de poliquetos del fondo marino frente a diferentes regímenes nutricionales

Analyses of body size of abyssal polychaetes were made from sites experiencing different levels of nutrient flux in the Pacific and Atlantic Oceans. Measuring polychaetes was problematical due to high levels of fragmentation, and width of the first chaetiger was used as a surrogate for body size. Results indicated that polychaetes were significantly smaller in Atlantic areas experiencing seasonal or periodic input of phytodetritus. This observation held not just for comparison of sizes of the total assemblage but also when comparisons were made at the family and species level. Not all families showed a response. In the Atlantic, individuals belonging to the families Cirratulidae, Spionidae and Sabellidae indicated size differences, while in the Pacific spionids were significantly smaller from phytodetrital sites. At the species level, six species - all deposit feeders - were significantly smaller from phytodetrital sites, while two nominally predator/omnivore species showed an increase in size. Two hypotheses for the size frequency of the Atlantic populations from phytodetrital sites are suggested &ndash; the juvenile recruitment hypothesis where the smaller population body size is because of an influx of newly recruited juveniles; and the allometric plasticity hypothesis which postulates a physiological response from populations from non-phytodetrital areas delaying reproduction and putting more energy into growth, hence resulting in a larger body size. It is hypothesised that the larger size in non-phytodetrital sites may be a response to starvation.Se han realizado an&aacute;lisis sobre el tama&ntilde;o de algunos poliquetos de zonas abisales marinas con diferentes niveles de flujo de nutrientes en los oc&eacute;anos Atl&aacute;ntico y Pac&iacute;fico. Dada la tendencia a romperse, la medici&oacute;n de dichos poliquetos fu&eacute; problem&aacute;tica. Por esta razon, la anchura del primer chaet&iacute;gero se ha tomado como sustituto del tama&ntilde;o total. Los resultados indican que los poliquetos eran notablemente m&aacute;s peque&ntilde;os en zonas donde el flujo de nutrientes era estacional u ocasional. &Eacute;sta observaci&oacute;n no solo se aplica a la totalidad de la poblaci&oacute;n, sino tambi&eacute;n al nivel taxon&oacute;mico familiar y por especies. No todas las familias mostraron dicha relaci&oacute;n. En el oc&eacute;ano Atl&aacute;ntico, individuos pertenecientes a las familias Cirratulidae, Spionidae y Sabellidae mostraron diferencias de tama&ntilde;o, mientras que en el oc&eacute;ano Pac&iacute;fico las familias Paraonidae y Spionidae eran de menor tama&ntilde;o en zonas con aportaci&oacute;n nutritiva. Al nivel de especie, seis especies, todas ellas detrit&iacute;voras, eran m&aacute;s peque&ntilde;as en zonas con flujo de nutrientes, y otras dos especies, ambas consideradas carn&iacute;voras/omn&iacute;voras, eran m&aacute;s grandes en dichas donas. Un an&aacute;lisis de frecuencia de los distintos tama&ntilde;os de poliquetos en estas zonas demuestran que el alto numero de tama&ntilde;os menores no ha sido causado por una afluencia de juveniles. Se especula que el mayor tama&ntilde;o de poliquetos encontrados en zonas con flujo de nutrientes estacional se debe a una reacci&oacute;n de inanici&oacute;n. &nbsp