Replacement gilts and early parity sows constitute a large, and increasing, proportion of modern breeding herds. Breeding herd profitability is therefore increasingly dependant on the efficiency of gilt management strategies as well as litter size at first farrowing; however, incidences of reproductive failures and small first litter sizes are common within cohorts of replacement gilts. Hence, this thesis had two primary aims which were addressed in four experiments; one, to identify whether the puberty stimulation and mating strategies developed for genotypes of 20 to 30 years ago are suitable for today’s heavier yet leaner genotypes; and two, to better understand the influence of pre-pubertal growth rate and metabolic status on reproductive maturation, puberty attainment and potential litter size. In experiment 1, 192 Large White/Landrace crossbred gilts were used to compare the effects on puberty attainment of commencing boar exposure at 161, 182 or 203 days of age, and the effect of first mating gilts at either the pubertal or second oestrus on ovulation rate and early embryo survival. Gilts were artificially inseminated at the allocated oestrus, with the reproductive tracts collected at 22.8 ± 0.4 days after first mating (mean ± S.E.M), and the numbers of corpora lutea and viable embryos recorded. Delaying first boar contact until 182 or 203 days of age significantly (P < 0.01) reduced days-to puberty and increased the proportion of gilts attaining puberty within 10 days of start of boar exposure. Gilt age at mating had no effect on potential litter size; however, there was a tendency for gilts mated at their second oestrus to shed 0.6 more ova, and possess one more embryo at day 20 of pregnancy. Experiment 2 determined the effects of long- (chronic) and short- (acute) term moderate dietary restriction on ovarian development and oocyte developmental competence in 161- and 175- day old, pre-pubertal gilts. Both chronic and acute periods of moderate feed restriction reduced the number of medium follicles present on the ovaries of 161- and 175-day old gilts, as well as the proportion of oocytes reaching Metaphase II in vitro. However, feeding level during the 14 days prior to ovary collection had the greatest effect on follicular growth and oocyte quality. Experiments 3 and 4 investigated the effects of the same dietary treatments on the timing of puberty attainment in response to boar exposure and potential litter size following mating at the pubertal oestrus. Chronic dietary restriction during the pre-pubertal period delayed puberty attainment, but the timing of the pubertal response was unaffected by acute, moderate dietary restriction of previously well-fed gilts during the period immediately prior to, and coincident with, boar exposure. Acute dietary restriction or repletion stimulated an increase or decrease, respectively, in pubertal ovulation rates; however, neither the number of viable embryo present on day 22 of gestation nor embryo survival were affected by the nutritional treatments used in these studies. Overall, these results demonstrate that the timing and synchrony of puberty attainment is significantly improved when gilts first receive boar exposure at 182 days of age (or older). It is, therefore, concluded that sexual maturity, as measured by responsiveness to boar contact, occurs later in modern genotypes. It is also evident that within the age range investigated, delaying first mating until the second oestrus does not significantly increase either ovulation rate or embryo number at day 20 post-mating. Further, the current data provide the first evidence that despite profoundly affecting the size and morphology of the antral follicle pool as well as pubertal ovulation rates, subtle alterations in dietary intake have no affect on the number or proportion of embryos surviving the pre-and peri-implantation period. It is evident the litter size of gilts mated at the pubertal oestrus is not determined by the number of ova shed, with the current data demonstrating that increasing ovulation rates results in increased embryo mortality. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1339082 / Thesis (Ph.D.) - University of Adelaide, School of Agriculture, Food and Wine, 2008

Fungi have been an important source for producing a wide range of secondary metabolites of widely differing chemical structures, as well as biological activities. Many of their metabolites now play a major role in pharmaceutical and agricultural industries. A number of fungi were isolated from soil and leaf litter collected from Arthur’s Pass, West Coast and Kaituna Valley using a particle filtration technique. Fungi were selected based on their unusual morphology or observed cytotoxicity and antimicrobial activity for large scale culture and extraction. A pale yellow compound was isolated from cytotoxic extracts from the culture of Aspergillus versicolor. This compound was identified as sterigmatocystin and the identity confirmed by UV profile and mass spectrometry. Five compounds were isolated from extracts prepared from two different species of Penicillium of which three were active against P388 cells (mycophenolic acid, cycloaspeptide A and mevastatin), one was active against dermatophytes (griseofulvin) and one was not active (3,4,6,8-tetrahydroxy-3-methyl-3,4-dihydroisocoumarin). Two compounds were isolated from extracts prepared from two different species of Phoma. A dark red compound was found to be novel and showed activity against P388 cells and Bacillus subtilis. A second compound also showing cytotoxicity was identified as the known compound phomenone. A further new compound was isolated from extracts of an identified dematiaceous fungus. This alkyl glucoside, however, was not bioactive.

Thesis (M.Ag.Sc.)--University of Adelaide, Dept. of Entomology, 1967. / Includes bibliographical references.

Thesis(M.S.)--Auburn University, 2006. / Abstract. Vita. Includes bibliographic references.

Thesis (M. Phil.)--University of Hong Kong, 2008. / Includes bibliographical references (leaf 152-169) Also available in print.

Thesis (MS)--University of Montana, 2010. / Contents viewed on May 28, 2010. Title from author supplied metadata. Includes bibliographical references.

Thesis (M.S.)--Montana State University--Bozeman, 2006. / Typescript. Chairperson, Graduate Committee: Cliff Montagne. Includes bibliographical references (leaves 63-70).

Thesis (M.S.)--Kent State University, 2008. / Title from PDF t.p. (viewed Oct. 27, 2009). Advisor: Laura Leff. Keywords: Phragmites australis; Scirpus cyperinus; glyphosate; microbes; ergosterol; invertebrates. Includes bibliographical references (p. 47-59).

The aim of this study was to reveal mechanisms of pH change in wood ant nests. Contents of basic cations and glucose brought in ant food, i.e., honeydew and prey, into the nests were measured. Manipulation experiment was carried out to test effects of glucose and Ca2+ cations brought by ants into the nest on increase in pH.

Nedskräpning medför problem för levande organismer och påverkar människors uppfattningar negativt och hur säkra de känner sig i ett område. Syftet med denna studie var att utvärdera nedskräpningssituationen inom tätorten Tumba, Botkyrka kommun, och försöka minska nedskräpning genom att förändra beteende genom att använda ”Nudging” där fotspår målas ut som leder mot papperskorgar inom fem mätpunkter. Tanken var att se om mängden skräp i papperskorgarna ökade och mängden skräp på marken minskade. En statistisk analys av kommunens insamlade data 2018–2020 utfördes och kompletterades av GIS för att identifiera tidsmässiga såväl som rumsliga förändringar inom området. Resultaten tyder på att nedskräpningen minskade med 49% från 2018–2020 (p &lt;0,02) och totalmängden per kvadratmeter var lägre än det nationella genomsnittet. Områden med högre befolkningstäthet var mest nedskräpade trots en högre städfrekvens och nedskräpningen förändrades inte beroende på avstånd till kollektivtrafik eller papperskorgar. Även om den upplevda skräpsituationen förbättrades från 2018–2019 försämrades den 2019–2020 (p &lt;0,01). Skräptyps kompositionen förändrades inte signifikant över perioden men cigarettfimpar var vanligare i Tumba jämfört med nationellt. En viss beteendeförändring kunde mätas. Data om papperskorgs vikt och skräpmängd samlades innan och efter nudging och testades med ett parat t-test. Inom 90% signifikansnivån var nudging effektiv (p = 0,08) med 21% mindre skräpmängd i mätpunkterna och 298% mer skräp i papperskorgarna. Det indikerar att nudging kan vara ett effektivt verktyg för att påverka nedskräpningsbeteenden men metoden var inte lika effektiv mot cigarettfimpar.