Thermal conductivity of sand and its effect on the temperature of Loggerhead Sea Turtle (Caretta Caretta) nests

The conductivity of sand at a depth of 30–50 cm was measured at 15 sites on the beach at Captiva Island in south-west Florida which is used by nesting loggerhead turtles (Caretta caretta). The mean daily temperature of the sand was correlated with conductivity at the same depth measured the same day (r=0·611). When day to day variation was removed the correlation between nest temperature and conductivity increased to 0·694. The sand was highly variable in its grain structure. The dominant variability (80·6%) was redescribed by the first two principal components of a Principal Components Analysis (PCA). These two components were influenced mostly by percentages of large (> 1 mm) and small (< 500 μm) grains respectively. Conductivity was strongly correlated with the grain structure of the sand. The first three principal components describing sand grain structure, explained 84·1% of the variation in conductivity. Moisture content of the sand (always < 5%) was not an important factor. Sites dominated by larger grains generally had poorer conductivity and were cooler. Comparisons of eight nests to seven adjacent random sites revealed no strong evidence for directional selection in nest placement relative to sand conductivity. The variance in conductivities recorded at nests was also not significantly different from the variance at random sites.

Rapid development of non-alcoholic steatohepatitis in Psammomys obesus (Israeli Sand Rat)

Background and AimsA major impediment to establishing new treatments for non-alcoholic steatohepatitis is the lack of suitable animal models that accurately mimic the biochemical and metabolic characteristics of the disease. The aim of this study was to explore a unique polygenic animal model of metabolic disease as a model of non-alcoholic steatohepatitis by determining the effects of 2% dietary cholesterol supplementation on metabolic and liver endpoints in Psammomys obesus (Israeli sand rat).MethodsP. obesus were provided ad libitum access to either a standard rodent diet (20% kcal/fat) or a standard rodent diet supplemented with 2% cholesterol (w/w) for 4 weeks. Histological sections of liver from animals on both diets were examined for key features of non-alcoholic steatohepatitis. The expression levels of key genes involved in hepatic lipid metabolism were measured by real-time PCR.ResultsP. obesus fed a cholesterol-supplemented diet exhibited profound hepatomegaly and steatosis, and higher plasma transaminase levels. Histological analysis identified extensive steatosis, inflammation, hepatocyte injury and fibrosis. Hepatic gene expression profiling revealed decreased expression of genes involved in delivery and uptake of lipids, and fatty acid and triglyceride synthesis, and increased expression of genes involved in very low density lipoprotein cholesterol synthesis, triglyceride and cholesterol export.ConclusionsP. obesus rapidly develop non-alcoholic steatohepatitis when fed a cholesterol-supplemented diet that appears to be histologically and mechanistically similar to patients.

Controlled field studies on soil aquifer treatment in a constructed coastal sandfill

A controlled artificial recharge experiment was conducted to investigate the effect of soil aquifer treatment during percolation of secondary and tertiary (ultrafiltered) treated wastewater through the shallow vadoze zone of a newly constructed coastal sandfill. The sandfill is a reclaimed land constructed from marine sand dredged from the seabed. To obtain 1-D flow, a stainless steel column was driven to a depth of 2.5 m, penetrating the phreatic surface. Wastewater was percolated through the column under fully-saturated and unsaturated conditions. Infiltration rates, dissolved organic carbon (DOC) and ultra-violet absorption (UVA) were monitored. The wastewaters were recharged at similar infiltration rates of approximately 5.5 m/day and 3.5 m/day under fully-saturated and unsaturated conditions, respectively. In both cases, clogging occurred 40 days after the start of recharge, under saturated conditions. For secondary treated wastewater, DOC concentration (mg/l) reduced by 28% and 13% under unsaturated and saturated conditions, respectively. The corresponding UVA reduction was 19.4% and 14.1%. Similar reductions in DOC were observed for the tertiary treated wastewater; however, the reduction in UVA was higher; 28% and 22% under unsaturated and saturated conditions, respectively. On an mass removal (mg/m(2) DOC) basis, DOC reduction appeared to be more significant under unsaturated conditions. This is attributed to the presence of interstitial oxygen.

Geochemical changes during recharge with tertiary-treated wastewater at a coastal sandfill

Results of experiments investigating geochemical changes during artificial recharge of treated wastewater at a coastal sandfill, reclaimed with sand dredged from the seabed, are reported in this paper. Laboratory batch experiments were conducted using secondary effluent (SE) and SE treated with an additional ultrafiltration process (UF), and wastewater treated by reverse osmosis (RO) process, mixed with surface sand obtained from the sandfill. Experiments with RO showed a net increase of 0.41 meq/L, 0.12 meq/L and 0.31 meq/L for Ca(2 + ), Mg(2 + ) and HCO(3) (-), respectively. UF and SE also exhibited net increase in Ca(2 + ), Mg(2 + ) and HCO(3) (-) indicating carbonate mineral dissolution. All three waters were found to be over-saturated with respect to calcite. Carbonate dissolution reactions were observed in the field experiments. However, the presence of imported clays from the borrow source gave rise to ion exchange reactions where Na(+) attached to the clay particles were exchanged for Ca(2 + ) and Mg(2 + ) inducing mineral dissolution, driven by sub-saturation conditions. This resulted in an increase in pH with maximum values in excess of 9.0. It was also found that the sodium adsorption ratio remained high (>10) even after the groundwater had been diluted sufficiently to freshwater levels (ionic strength, I <0.015) indicating a potential for the dispersion of clay particles. This could have a deleterious consequence on porosity and hydraulic conductivity.

In hot pursuit : fluctuating mating system and sexual selection in sand lizards

A changing climate is expected to have profound effects on many aspects of ectotherm biology. We report on a decade-long study of free-ranging sand lizards (Lacerta agilis), exposed to an increasing mean mating season temperature and with known operational sex ratios. We assessed year-to-year variation in sexual selection on body size and postcopulatory sperm competition and cryptic female choice. Higher temperature was not linked to strength of sexual selection on body mass, but operational sex ratio (more males) did increase the strength of sexual selection on body size. Elevated temperature increased mating rate and number of sires per clutch with positive effects on offspring fitness. In years when the “quality” of a female's partners was more variable (in standard errors of a male sexual ornament), clutches showed less multiple paternity. This agrees with prior laboratory trials in which females exercised stronger cryptic female choice when male quality varied more. An increased number of sires contributing to within-clutch paternity decreased the risk of having malformed offspring. Ultimately, such variation may contribute to highly dynamic and shifting selection mosaics in the wild, with potential implications for the evolutionary ecology of mating systems and population responses to rapidly changing environmental conditions.

DOC and UVA attenuation with soil aquifer treatment in the saturated zone of an artificial coastal sandfill

Results from a direct recharge experiment conducted in the field to investigate DOC and UVA(254) attenuation rates during the direct injection of UF treated wastewater into a artificial coastal sandfill are presented in this paper. Approximately 500 m(3) of ultra-filtered wastewater was injected into the saturated zone, over a period of 9 days. The movement of the plume was tracked over 80 days, during which time samples were obtained from multilevel samplers installed in transects across the drift axis of the plume. An analysis of fluorescein in the samples obtained during the drift of the UF plume showed that DOC and UVA were attenuated beyond rates predicted by conservative mixing, by up to a maximum of 45%. A degradation coefficient of 0.0175 day(-1) was found to be applicable for DOC degradation. After a drift period of 80 days, DOC and UVA reduced to approximately 4.5 mg/l and 0.100 cm(-1), respectively, from initial values of 8.06 mg/l and 0.199 cm(-1).

Maternal dietary supplementation with saturated, but not monounsaturated or polyunsaturated fatty acids, leads to tissue-specific inhibition of offspring Na+,K+-ATPase

In rats, a maternal diet rich in lard is associated with reduced Na+,K+-ATPase activity in adult offspring kidney. We have addressed the role of different fatty acids by evaluating Na+,K+-ATPase activity in offspring of dams fed diets rich in saturated (SFA), monounsaturated (MUFA) or polyunsaturated (PUFA) fatty acids. Female Sprague–Dawley rats were fed, during pregnancy and suckling, a control diet (4% w/w corn oil) or a fatty acid supplemented diet (24% w/w). Offspring were reared on chow (4% PUFA) and studied at 6 months. mRNA expression (real-time PCR) of Na+,K+-ATPase α subunit and protein expression of Na+,K+-ATPase subunits (Western blot) were assessed in kidney and brain. Na+,K+-ATPase activity was reduced in kidney (P < 0.05 versus all groups) and brain (P < 0.05 versus control and MUFA offspring) of the SFA group. Neither Na+,K+-ATPase α1 subunit mRNA expression, nor protein expression of total α, α1, α2, α3 or β1 subunits were significantly altered in kidney in any dietary group. In brains of SFA offspring α1 mRNA expression (P < 0.05) was reduced compared with MUFA and PUFA offspring, but not controls. Also in brain, SFA offspring demonstrated reduced (P < 0.05) α1 subunit protein and increased phosphorylation (P < 0.05) of the Na+,K+-ATPase modulating protein phospholemman at serine residue 63 (S63 PLM). Na+,K+-ATPase activity was similar to controls in heart and liver. In utero and neonatal exposure to a maternal diet rich in saturated fatty acids is associated with altered activity and expression of Na+,K+-ATPase in adulthood, but mechanisms appear tissue specific.

The effect of oral administration of iron saturated-bovine lactoferrin encapsulated chitosan-nanocarriers on osteoarthritis

In this study, the therapeutic potentials of 100% iron saturated-bovine lactoferrin encapsulated in alginate-chitosan polymeric nanocarriers (AEC-CP-Fe-bLf-NCs) were examined in in vitro inflammatory OA model and in collagen-induced arthritis (CIA) mice. Oral administration of nanocarriers in mice were non-toxic and significantly induced disease modifying activity by reducing joint inflammation and downregulating the expression of catabolic genes, IL-1β, NO, JNK and MAPK. In addition, up-regulation of type II collagen, aggrecan and inflammation depleted iron and calcium metabolisms via inhibition of miRNA of iron transporting receptors was shown in AEC-CP-Fe-bLf-NCs treated mice.

Babes in the sand and flying predators : touristic corruption, exoticism and neocolonialism in Chandani Lokugé’s 'Turtle Nest'

In Chandani Lokugé’s Turtle Nest the Sri Lankan beach is a savage environment, a dystopia, where local children are molested by Western paedophile tourists. This essay examines representations of child vulnerability, exoticism, neocolonialism and envy in the novel. It reads these issues in the context of postcolonial tourism in Sri Lanka and elsewhere. It establishes connections between the commodification of children in Lokugé’s story and the real-world progress of exoticist tourism.