Compaction of till soils and growth tests with Norway spruce and scots pine

Five of the most common soils in forest areas in Sweden, viz., coarse sand, fine sand, coarse sandy till, medium sandy till and fine sandy till soil, were compressed at different loadings for 10 min. In the soils studied, it was found that the more fine material there was in the soil, the easier it compacted, and that till soils compacted much more than sediments of the same main particle class. The chosen compression time seemed to correspond well with an equilibrium level of static compaction. Influence of wall friction in compression tubes was found to be negligible for till soils.After compaction the soil cores were sown with Norway spruce (Picea abies (L.) Karst.) or Scots pine (Pinus sylvestris L.) and 16–20 days later the root lengths were recorded. Lengths of primary roots in per cent of the control were found to be almost inverse to the compaction of the soils; Norway spruce was more impeded than Scots pine. Thus, the bulk density alone is a poor indicator of the impact of soil compaction. Growth to 26, 33 and 120 days showed that the extension of secondary roots might be more impeded by compaction than the primary roots. Fertilization increased growth but did not decrease the growth difference between seedlings on unloaded and loaded soil cores.     

Curing and degradation processes of cement-bonded particleboard by supercritical CO<Subscript>2</Subscript> treatment

This study examined the effects of supercritical CO₂ treatment on the curing and degradation of cementbonded particleboard (CBP). Significant correlations were found between the supercritical CO₂ treatment and mechanical properties during both curing and degradation processes. Internal bond (IB) strength, modulus of rupture (MOR), and modulus of elasticity (MOE) values of CBP achieved their maximums by supercritical CO₂ treatment in 30 min. These conditions indicated that supercritical CO₂ treatment accelerates the curing process rapidly and enhances the mechanical properties of the CBP. However, these values decreased in treatment from 60 min to 10 days and had a negative effect on board performance, indicating that supercritical CO₂ treatment over a longer time span leads to degradation of the CBP. Furthermore, X-ray diffractometry (XRD), thermal gravimetry (TG-DTG), and scanning electron microscopy (SEM) observation clarified that the mechanisms of degradation are directly affected by the mineralogical composition of the system, in par ticular, by the calcium carbonate content as caused by carbonation.     

Nature-based tourism impacts on yellow-eyed penguins Megadyptes antipodes: does unregulated visitor access affect fledging weight and juvenile survival?

The Otago Peninsula, South Island, New Zealand offers tourists opportunities for unregulated access to breeding sites of the yellow-eyed penguin (Megadyptes antipodes). The presence of people on beaches delays post-foraging landing by penguins, which in turn may affect the amount of food delivered by parents to their chicks, with consequences for chick growth and fledging mass. This study explored the relationship between human disturbance and yellow-eyed penguin chick fledging weight and survival by comparing five yellow-eyed penguin breeding areas with different levels of visitor frequency. We investigated whether chick fledging weights vary between breeding areas, and whether fledging weight is a predictor of juvenile survival. In 2002, chicks at Sandfly Bay, an area with high numbers of tourists, had significantly lower fledging weights than chicks at Highcliff, an area with no tourist visitors. An analysis of sightings of 2125 yellow-eyed penguin chicks banded between 1981 and 2000 indicated probability of survival was positively associated with mass at fledging. Thus lower fledging weights may have long-term population consequences. Fledging weight is influenced by many factors, however the results suggest the possibility of an effect of tourist numbers on chick fledging weight. This is noteworthy, especially in light of the rapid rate at which wildlife tourism is increasing in coastal areas of southern New Zealand.     

An experimental approach to the photolysis of pesticides adsorbed on soil: Thidiazuron

An experimental procedure has been developed for conducting photolysis studies with pesticides adsorbed by soil surfaces. In these experiments, solutions of thidiazuron were sprayed on segments of a 0.5-mm layer of soil covering a glass plate. The soil surface was irradiated using simulated sunlight. The light source was a xenon arc in combination with glass filters that absorbed light of wavelength <290 nm. During irradiation, one half of the sprayed areas was covered to obtain nonirradiated samples. After various time intervals, groups of three irradiated and three non-irradiated segments of the soil were scraped off and extracted; the extracts were analysed. Information was obtained on the photoproducts formed and on the kinetics of photodegradation of thidiazuron.     

Effect of Dimethyl sulfoxide (DMSO) and egg yolk on sperm motility,fertility and hatching rates of depik Rasbora tawarensis (Pisces: Cyprinidae) eggs after short‐term cryopreservation

Cryoprotectant is the crucial factor in the cryopreservation process. In general, there are two types of cryoprotectant, permeating and non‐permeating cryoprotectants. Dimethyl sulfoxide (DMSO) and egg yolk are common permeating and non‐permeating cryoprotectants respectively. Hence, the objective of the present study was to determine the best proportion of DMSO and egg yolk for the cryopreservation of Rasbora tawarensis sperm. A completely randomized experimental design was used in this study which involves two types of cryoprotectant and their combination at different concentrations, namely 5% DMSO, 5% egg yolk, 5% DMSO + 5% egg yolk and 2.5% DMSO + 2.5% egg yolk. Every treatment was conducted in three replicates. Combination of 5% DMSO + 5% egg yolk gave the best results cryoprotectant treatment had significant effects on sperm motility, fertilization and hatching rate of the R. tawarensis eggs (p < .05). It is concluded that the best proportion of cryoprotectants for sperm cryopreservation in this species is 5% DMSO + 5% egg yolk.     

Polycitorols A and B,New Tricyclic Alkaloids from an Ascidian

Two new tricyclic alkaloids, polycitorols A (1) and B (2) have been isolated along with the known lepadiformine (3) from a marine ascidian of the family Polycitoridae. The structures of the new compounds were elucidated by analysis of NMR data and comparison with those of 3 and other related compounds [1–5]. Compounds 1 and 2 are closely related to cylindricines A and B, lacking C-4 oxygenation found in cylindricines and having a butyl instead of a hexyl appendage. NOE experiments on compounds 1 and 2 suggested the A/B ring fusion to be cis.     

Physical and hydraulic properties of baked ceramic aggregates used for plant growth medium.

Baked ceramic aggregates (fritted clay, arcillite) have been used for plant research both on the ground and in microgravity. Optimal control of water and air within the root zone in any gravity environment depends on physical and hydraulic properties of the aggregate, which were evaluated for 0.25-1-mm and 1-2-mm particle size distributions. The maximum bulk densities obtained by any packing technique were 0.68 and 0.64 g cm-3 for 0.25-1-mm and 1-2-mm particles, respectively. Wettable porosity obtained by infiltration with water was approximately 65%, substantially lower than total porosity of approximately 74%. Aggregate of both particle sizes exhibited a bimodal pore size distribution consisting of inter-aggregate macropores and intra-aggregate micropores, with the transition from macro- to microporosity beginning at volumetric water content of approximately 36% to 39%. For inter-aggregate water contents that support optimal plant growth there is 45% change in water content that occurs over a relatively small matric suction range of 0-20 cm H2O for 0.25-1-mm and 0 to -10 cm H2O for 1-2-mm aggregate. Hysteresis is substantial between draining and wetting aggregate, which results in as much as a approximately 10% to 20% difference in volumetric water content for a given matric potential. Hydraulic conductivity was approximately an order of magnitude higher for 1-2-mm than for 0.25-1-mm aggregate until significant drainage of the inter-aggregate pore space occurred. The large change in water content for a relatively small change in matric potential suggests that significant differences in water retention may be observed in microgravity as compared to earth.     

Characterization of a Novel Resistant‐Starch and Its Effects on Postprandial Plasma‐Glucose and Insulin Responses

Objectives of this study were to understand the physicochemical properties of a novel resistant starch (RS) made by complexing high‐amylose maize starch VII (HA7) with palmitic acid (PA), and its effects on reducing postprandial plasma‐glucose and insulin responses. The HA7 starch was heat‐treated and debranched using isoamylase (ISO) to enhance the starch‐lipid complex formation. The RS content of the HA7 starch debranched with ISO and complexed with PA (HA7+ISO+PA) was 52.7% determined using AOAC Method 991.43 for dietary fiber, which was greater than that of the HA7 control (35.4%). The increase in the RS content of the HA7+ISO+PA sample was attributed to the formation of retrograded debranched‐starch and starch‐lipid complex. The postprandial plasma‐glucose and insulin responses of 20 male human‐subjects after ingesting bread made from 60% (dry basis) HA7+ISO+PA were reduced to 55 and 43%, respectively, when compared with those after ingesting control white bread (as 100%) containing the same amount of total carbohydrates. The results suggested that the HA7+ISO+PA can be used for the interventions of insulin resistance and metabolic syndrome, including diabetes and obesity.     

Myoglobin as a prognostic indicator for outcome in dogs with gastric dilatation-volvulus

Objective – To determine whether myoglobin (Mb) is a useful prognostic indicator for outcome and to investigate any relationship between Mb and mortality in dogs with gastric dilatation‐volvulus (GDV). Design – Prospective study. Setting – Veterinary teaching hospital. Animals – Seventy‐two dogs with GDV. Interventions – Blood sampling. Measurements and Main Results – Mb levels were measured at the time of diagnosis (Mbt₀), 24 hours (Mbt₁), and 48 hours (Mbt₂) after signs of GDV were recognized. Fifty‐seven dogs survived (group I) and 15 dogs did not survive (group II). Mb t₀ differed significantly between groups (P=0.04). Mbt₀ in group I ranged from <30 to >700 ng/mL (n=57, median 74 ng/mL), and in group II from 34 to >700 ng/mL (n=15, median 238 ng/mL). Analysis of a receiver operating characteristic curve of Mbt₀ suggested that the best single cutpoint would be 168 ng/mL (sensitivity 60.0%, specificity 84.2%). Fifty percent of dogs with Mbt₀>168 ng/mL were euthanized, while 88.9% with Mbt₀<168 ng/mL survived. Mbt₁ and Mbt₂ differed significantly between groups I and II. Mbt₁ in group I ranged from 32 to >700 ng/mL (n=55, median 123 ng/mL), and Mbt₁ in group II ranged from 131 to 643 ng/mL (n=7, median 343 ng/mL) (P=0.006). Mbt₂ in group I ranged from 30 to 597 ng/mL (n=54, median 101 ng/mL), and in group II from 141 to >700 ng/mL (n=8, median 203 ng/mL) (P=0.02). Conclusions – In this study, Mbt₀ is a moderately sensitive and specific prognostic indicator. Almost 90% of the dogs below the cutpoint survived to discharge, whereas 50% with Mbt₀ above the cutpoint did not survive.     

Evaluation of lymphocyte apoptosis in dogs with inflammatory bowel disease

Objective-To determine whether lymphocyte apoptosis in intestinal mucosae is more common in healthy dogs than dogs with inflammatory bowel disease (IBD) and whether numbers of apoptotic cells increase after successful treatment of affected dogs. Animals-8 dogs with IBD (IBD dogs) and 8 healthy control dogs. Procedures-Biopsy specimens of the duodenum and colon were obtained via endoscopy from dogs with IBD before and after 10 weeks of standard treatment and compared with specimens obtained from control dogs. Expression of activated caspase 3 (Casp3), caspase-cleaved fragment p85 from poly-ADP-ribose polymerase (PARP), and B-cell leukemia/lymphoma 2 (Bcl-2) was measured in the duodenal (villous tip and base) and colonic mucosae. Results-Expression of Casp3 was greater in the duodenal villous tips of control dogs, compared with expression in similar tissues from dogs with IBD before or after treatment. Despite clinical improvement of dogs with IBD, expression of Casp3 did not increase after treatment. Expression of PARP did not differ between groups at any time point. Expression of Bcl-2 was greater at all 3 tissue sites in control dogs, compared with expression at the same sites in dogs with IBD. Furthermore, Bcl-2 expression in duodenal villous tips was higher in dogs with IBD after treatment but was not higher elsewhere. In control dogs, expression patterns for all 3 markers were similar between sites (villous tip > villous base > colon). Conclusions and Clinical Relevance-Expression of Casp3 in lymphocytes in duodenal villous tips was significantly reduced in dogs with IBD, compared with expression in healthy dogs, but no increase was detected following successful treatment of IBD. Increased expression of Bcl-2 may be a potential marker of the success of treatment.