Landslides in sensitive soils, Tauranga, New Zealand.

In the Tauranga region sensitive soil failures commonly occur after heavy rainfall events, causing considerable infrastructure damage. Several notable landslides include a large failure at Bramley Drive, Omokoroa in 1979, the Ruahihi Canal collapse in 1981, and numerous landslides in May 2005; recently the Bramley Drive scarp was reactivated in 2011. These failures are associated with materials loosely classified as the Pahoia Tephras - a mixture of rhyolitic pyroclastic deposits of approximately 1 Ma. The common link with extreme rainfall events suggests a pore water pressure control on the initiation of these failures. Recent research on the structure of the soils shows a dominance of halloysite clay minerals packed loosely in arrangements with high porosity (51 – 77 %), but with almost entirely micropores. This leads us to conclude that the permeability is very low, and the materials remain continuously wet. The formation of halloysite is encouraged by a wet environment with no episodes of drying, supporting this assumption. A high-resolution CPT trace at Bramley Drive indicates induced pore water pressures rising steadily to a peak at approximately 25 m depth; this depth coincides with the base of the landslide scarp. We infer that elevated pore water pressures develop within this single, thick aquifer, triggering failure through reduced effective stresses. The inactive halloysite clay mineral results in low plasticity indices (13 – 44 %) and hence high liquidity indices (1.2 – 2.4) due to the saturated pore space; remoulding following failure is sudden and dramatic and results in large debris runout distances

μ\mu--PhotoZ: Photometric Redshifts by Inverting the Tolman Surface Brightness Test

Surface brightness is a fundamental observational parameter of galaxies. We show, for the first time in detail, how it can be used to obtain photometric redshifts for galaxies, the $\mu$-PhotoZ method. We demonstrate that the Tolman surface brightness relation, $\mu \propto (1+z)^{-4}$, is a powerful tool for determining galaxy redshifts from photometric data. We develop a model using $\mu$ and a color percentile (ranking) measure to demonstrate the $\mu$-PhotoZ method. We apply our method to a set of galaxies from the SHELS survey, and demonstrate that the photometric redshift accuracy achieved using the surface brightness method alone is comparable with the best color-based methods. We show that the $\mu$-PhotoZ method is very effective in determining the redshift for red galaxies using only two photometric bands. We discuss the properties of the small, skewed, non-gaussian component of the error distribution. We calibrate $\mu_r, (r-i)$ from the SDSS to redshift, and tabulate the result, providing a simple, but accurate look up table to estimate the redshift of distant red galaxies.Comment: Accepted for publication in the Astronomical Journa

A target repurposing approach identifies N-myristoyltransferase as a new candidate drug target in filarial nematodes

Myristoylation is a lipid modification involving the addition of a 14-carbon unsaturated fatty acid, myristic acid, to the N-terminal glycine of a subset of proteins, a modification that promotes their binding to cell membranes for varied biological functions. The process is catalyzed by myristoyl-CoA:protein N-myristoyltransferase (NMT), an enzyme which has been validated as a drug target in human cancers, and for infectious diseases caused by fungi, viruses and protozoan parasites. We purified Caenorhabditis elegans and Brugia malayi NMTs as active recombinant proteins and carried out kinetic analyses with their essential fatty acid donor, myristoyl-CoA and peptide substrates. Biochemical and structural analyses both revealed that the nematode enzymes are canonical NMTs, sharing a high degree of conservation with protozoan NMT enzymes. Inhibitory compounds that target NMT in protozoan species inhibited the nematode NMTs with IC50 values of 2.5-10 nM, and were active against B. malayi microfilariae and adult worms at 12.5 µM and 50 µM respectively, and C. elegans (25 µM) in culture. RNA interference and gene deletion in C. elegans further showed that NMT is essential for nematode viability. The effects observed are likely due to disruption of the function of several downstream target proteins. Potential substrates of NMT in B. malayi are predicted using bioinformatic analysis. Our genetic and chemical studies highlight the importance of myristoylation in the synthesis of functional proteins in nematodes and have shown for the first time that NMT is required for viability in parasitic nematodes. These results suggest that targeting NMT could be a valid approach for the development of chemotherapeutic agents against nematode diseases including filariasis

Effects of 8-Week Ketogenic Diet on Anthropometrics, Body Composition, Metabolic Parameters, and Psychological Factors in Young Obese Population

Obese have a significantly higher Body Mass Index (BMI), which can be associated with poor nutritional intake and sedentary lifestyles. The ketogenic diet is a form of a dietary intervention which is often implemented for metabolic syndrome individuals such as obese populations. PURPOSE: The purpose of this study was to measure the effects of a ketogenic diet on anthropometrics, body composition, metabolic parameters, and psychological factors in young obese population. METHODS: Seven young obese participants (n=7, height (cm); 174.8 ± 10.9, weight (kg); 105 ± 20.7, BMI (kg∙m-2); 34.6 ± 4.8) completed an 8-week intervention with a 70:20:10 ratio of fats to proteins to carbohydrates. Participants within the study were provided three meals per day, for a total of 8 weeks. Statistical analyses were performed with IBM Statistical Package for Social Science (SPSS 27.0, SPSS Inc., Chicago, USA). All data was reported as mean and standard deviation (SD). Dependent paired t-Test was used to determine ketogenic diet intervention effects. Frequencies were used to measure results from psychological factors. Statistical significance was set a priori p ≤ 0.05. RESULTS: Participants within the study noted significant reductions in anthropometric variables during 8 weeks: body mass (Pre: 105.8 ± 20.5 kg Post: 98.9 ± 18.8 kg, p= 0.000), BMI (Pre: 34.6 ± 4.8 kg·m-2, Post: 32.2 ± 4.2 kg·m-2, p= 0.001), waist circumference (Pre: 101.5 ± 13.9 cm, Post: 96.3 ± 13.3 cm, p= 0.000), and hip circumference (Pre: 112.6 ± 11.5 cm, Post: 107.3 ± 10.8 cm, p= 0.000). Significant reductions were shown in body composition variables: body fat (Pre: 25.6 ± 0.8%, Post: 21.1 ± 1.4%, p=0.000), and lean body mass (Post: 78.9 ± 14.9 kg, Post: 78.2 ± 14.5 kg, p=.0035). Significant reductions were shown in metabolic parameters: systolic blood pressure (Post: 126.6 ± 10.0 mmHg, Post: 120 ± 6.6 mmHg, p=0.029), diastolic blood pressure (Pre: 81.7 ± 4.9 mmHg, Post: 76.3 ± 1.8 mmHg, p= 0.020), and VO2max (Pre: 47.6 ± 8.9 mL·kg-1·min-1, Post: 51.8 ± 9.2 mL·kg-1·min-1, p=0.001. Question 1 within the psychological questionnaire results shown a reduction in the negative aspect in poor health score, with a significant increase shown towards good health. Question 3g results shown that here was a significant increase in frequencies of improvement towards having no limitations regarding walking a one-mile distance. Question 9g had significant increase in individuals selecting improved overall energy levels in comparison to baseline. CONCLUSION: The 8 weeks of ketogenic diet intervention may contribute or change bioenergetics pathways and results in significant adaptations on anthropometrics, body composition, metabolic parameters, and psychological factors in young obese population

Discovery of halloysite books in altered silicic Quaternary tephras, northern New Zealand

Hydrated halloysite was discovered in books, a morphology previously associated exclusively with kaolinite. From ~1.5 μm to ~1500 μm in length, the books showed significantly greater mean Fe contents (Fe2O3 = 5.2 wt%) than tubes (Fe2O3 = 3.2 wt%), and expanded rapidly with formamide. They occurred, along with halloysite tubes, spheroids, and plates, in highly porous yet poorly-permeable, silt-dominated, Si-rich, pumiceous rhyolitic tephra deposits aged ~0.93 Ma (Te Puna tephra) and ~0.27 Ma (Te Ranga tephra) at three sites ~10-20 m stratigraphically below the modern land-surface in the Tauranga area, eastern North Island, New Zealand. The book-bearing tephras were at or near saturation, but have experienced intermittent partial drying, favouring the proposed changes: solubilized volcanic glass + plagioclase -> halloysite spheroids -> halloysite tubes -> halloysite plates -> halloysite books. Unlike parallel studies elsewhere involving both halloysite and kaolinite, kaolinite has not formed in Tauranga presumably because the low permeability ensures the sites largely remain locally wet so that the halloysite books are metastable. An implication of the discovery is that some halloysite books in similar settings may have been misidentified previously as kaolinite

Spitzer/IRAC Limits to Planetary Companions of Fomalhaut and epsilon Eridani

Fomalhaut and epsilon Eridani are two young, nearby stars that possess extended debris disks whose structures suggest the presence of perturbing planetary objects. With its high sensitivity and stable point spread function, Spitzer/IRAC is uniquely capable of detecting cool, Jupiter-like planetary companions whose peak emission is predicted to occur near 4.5 um. We report on deep IRAC imaging of these two stars, taken at 3.6 and 4.5 um using subarray mode and in all four channels in wider-field full array mode. Observations acquired at two different telescope roll angles allowed faint surrounding objects to be separated from the stellar diffraction pattern. No companion candidates were detected at the reported position of Fomalhaut b with 3 sigma model-dependent mass upper limits of 3 MJ (for an age of 200 Myr). Around epsilon Eridani we instead set a limit of 4 and <1 MJ (1 Gyr model age) at the inner and outer edge of the sub-millimeter debris ring, respectively. These results are consistent with non-detections in recent near-infrared imaging searches, and set the strongest limits to date on the presence of planets outside epsilon Eridani sub-millimeter ring.Comment: Accepted by The Astrophysical Journal. Request electronic-only plates to M. Marengo ([email protected]

Hectospec, the MMT's 300 Optical Fiber-Fed Spectrograph

The Hectospec is a 300 optical fiber fed spectrograph commissioned at the MMT in the spring of 2004. A pair of high-speed six-axis robots move the 300 fiber buttons between observing configurations within ~300 s and to an accuracy ~25 microns. The optical fibers run for 26 m between the MMT's focal surface and the bench spectrograph operating at R~1000-2000. Another high dispersion bench spectrograph offering R~5,000, Hectochelle, is also available. The system throughput, including all losses in the telescope optics, fibers, and spectrograph peaks at ~10% at the grating blaze in 1" FWHM seeing. Correcting for aperture losses at the 1.5" diameter fiber entrance aperture, the system throughput peaks at $\sim$17%. Hectospec has proven to be a workhorse instrument at the MMT. Hectospec and Hectochelle together were scheduled for 1/3 of the available nights since its commissioning. Hectospec has returned \~60,000 reduced spectra for 16 scientific programs during its first year of operation.Comment: 68 pages, 28 figures, to appear in December 2005 PAS

Micro- and nano-fluidics around HAB cells

Have you ever wondered how algae stay so clean? Most flowering-plant leaves also stay clean. Under air, films of water and “dirt” are repelled. Repulsion forces the water into droplets that easily roll off because these leaves are covered in hydrophobic nm- to µm- sized grooves and pillars, producing superhydrophobicity (SH) at the surface. Similarly, most algal cells bear a glycocalyx of organic fibrils that give surface structure, and are often hydrophobic. Glycocalyxes serve many functions, but whether they produce SH is poorly known. SH coatings are being developed to prevent fouling of ships and aquaculture structures without using toxins, so this technology could help understand how algae defeat fouling. Glycocalyxes are composed of exopolymeric secretions (EPS), and algae sometimes make the water more viscous using this tightly and more loosely bound EPS. EPS is also sometimes sticky. SH cuticles on copepods may change ambient fluid microdynamics by allowing slip at their surfaces, and facilitate filter feeding. By managing ambient viscosity and surface properties including slipping and sticking, algae may have the tools to engineer ambient fluidics and stay clean and unfouled