The Pahala swarm of earthquakes in Hawai'i.

A magma network may feed into different volcanoes, including Mauna Loa and Kilauea.

Post Audit of Simulated Groundwater Flow to a Short-Lived (2019 to 2020) Crater Lake at Kilauea Volcano.

About 14.5 months after the 2018 eruption and summit collapse of Kilauea Volcano, Hawai'i, liquid water started accumulating in the deepened summit crater, forming a lake that attained 51 m depth before rapidly boiling off on December 20, 2020, when an eruption from the crater wall poured lava into the lake. Modeling the growth of the crater lake at Kilauea summit is important for assessing the potential for explosive volcanism. Our current understanding of the past 2500 years of eruptive activity at Kilauea suggests a slight dominance of explosive behavior over effusive. The deepened summit crater and presence of the crater lake in 2019 raised renewed concerns about explosive activity. Groundwater models using hydraulic-property data from a nearby drillhole successfully forecast the timing and rate of lake filling. Here we compare the groundwater-model predictions with observational data through the demise of the crater lake, examine the implications for local water-table configuration, consider the potential role of evaporation and recharge (neglected in previous models), and briefly discuss the energetics of the rapid boil-off. This post audit of groundwater-flow models of Kilauea summit shows that simple models can sometimes be used effectively to simulate complex settings such as volcanoes.

Effects of a 3-week High-Fat-Low-Carbohydrate Diet on Lipid and Glucose Profiles in Experienced, Middle-age Male Runners.

This study examined glucose and lipid marker responses following a 3-week, ad libitum low-carbohydrate-high-fat diet (LCHF; ~70% kcals from fat, <50 g/day of net carbohydrates) versus the habitual mixed macronutrient diet (HMD) of eight middle-age, trained male runners (40 ± 10 years; V̇O2peak = 49 ± 4 mL·kg-1·min-1). Blood was drawn at 0600 from an antecubital vein after an overnight fast under conditions of no exercise/heat stress (NEXH; 48 h of restriction from intense exercise) or 24-h after exercise/heat stress (EXH; 60 min run in hot conditions plus 5-km time trial) for both dietary conditions. Glucose improvement during LCHF approached but did not reach statistical significance (p = 0.07). Pre-exercise triacylglycerol did not differ between treatments but decreased > 20 mg/dL (p < 0.05) for both treatments from NEXH to EXH (HMD = 42 ± 16; LCHF = 35 ± 21 mg/dL). Main effects for diet were exhibited for HDL-C during NEXH and EXH (HMD = 48 ± 10 and 50 ± 11; LCHF = 57 ± 13 and 60 ± 13 mg/dL), and LDL-C also increased (p = 0.02) by ~20 mg/dL for LCHF at both collection points resulting in ~30 mg/dL greater total cholesterol for LCHF before and 24-h after exercise (p < 0.05). A 3-week, ad libitum LCHF did not elicit significant negative cardiovascular disease risk in male runners 30-50 years of age with healthy pre-intervention lipid and glucose marker status.

Effects of Ad libitum Low-Carbohydrate High-Fat Dieting in Middle-Age Male Runners.

PURPOSE: This study examined the effects of a 3-wk ad libitum, low-carbohydrate (<50 g·d) high-fat (~70% of calories) (LCHF) diet on markers of endurance performance in middle-age, recreationally competitive male runners. METHODS: All subjects (n = 8) after their normal high-carbohydrate (HC) diet had anthropometric measures assessed and completed five 10-min running bouts at multiple individual race paces in the heat while physiological variables, metabolic variables, and perceptual responses were recorded. After 20 min of rest, participants completed a 5-km time trial on a road course. Subjects then consumed an LCHF diet for 3 wk and returned for repeat testing. RESULTS: Body mass and seven-site skinfold thickness sum decreased by approximately 2.5 kg (P < 0.01) and 13 mm (P < 0.05) after LCHF diet. Rectal temperature was higher after the first 10 min of exercise (37.7°C ± 0.3°C vs 37.3°C ± 0.2°C) in the HC diet but did not differ at any other time with LCHF diet. Heart rate and perceptual measures did not display any consistent differences between treatments excluding thirst sensation for LCHF diet. RER and carbohydrate oxidation declined significantly, whereas fat oxidation increased after LCHF diet for every pace (P < 0.01). There was no significant difference (P = 0.25) in a 5-km time trial performance, but LCHF diet (23.45 ± 2.25 min) displayed a trend of improved performance versus HC (23.92 ± 2.57 min). CONCLUSION: Improved body composition and fat oxidation from LCHF diet potentially negate expected performance decrement from reduced carbohydrate use late in exercise for nonelite runners. An acute decrease in training capacity is expected; however, if performance improvement is not exhibited after 3 wk, diet cessation is suggested for negative responders.

Five-Kilometer Time Trial Reliability of a Nonmotorized Treadmill and Comparison of Physiological and Perceptual Responses vs. a Motorized Treadmill.

Waldman, HS, Heatherly, AJ, Waddell, AF, Krings, BM, and O'Neal, EK. Five-kilometer time trial reliability of a nonmotorized treadmill and comparison of physiological and perceptual responses vs. a motorized treadmill. J Strength Cond Res 32(5): 1455-1461, 2018-This study examined the reliability of running performance across 3 nonmotorized treadmill (NMT) 5-km time trials (TTs) and physiological, gait, and perceptual differences at a 5-km pace for both NMT and motorized treadmills (MTs). Ten male runners experienced in road racing who had never run on an NMT completed 3 TT to establish personal best 5-km pace. In a later session, participants ran at this pace for 5 minutes on the NMT while metabolic, gait, and perceptual measures were recorded and then ran at outdoor 5-km personal best pace on an MT at 1% grade (counter-balanced crossover design). Intraclass correlation (ICC = 0.95) between the TT1 and TT2 was strong but improved between TT2 and TT3 (ICC = 0.99) with considerable reduction in variability. Nonmotorized treadmill resulted in a 24% slower pace (10.6 ± 1.5 vs. 13.9 ± 2.6 km·h; p < 0.001), shorter stride length (1.02 ± 0.10 vs. 1.27 ± 0.18 m; p < 0.001), and decreased cadence (175 ± 12 vs. 181 ± 13 steps per·minute; p = 0.01). However, V[Combining Dot Above]O2, respiratory exchange ratio (RER), lactate concentration, and heart rate did not differ between modalities (NMT = 3.4 ± 0.4 L·min, 0.96 ± 0.04, 6.9 ± 3.7 mmol, 172 ± 10 b·min; MT = 3.4 ± 0.5 L·min, 0.96 ± 0.04, 5.7 ± 3.4 mmol, 170 ± 10 b·min). rate of perceived exertion (RPE) for legs, breathing, and overall did not differ between treadmill types. A familiarization session should be included for TT using NMT. Other than gait and pace characteristics similar responses were elicited by both treadmills when running at 5-km pace. However, with these considerations, NMT TT of 4-km might be more appropriate in matching MT 5-km TT duration without altering physiological responses significantly.

Publisher Correction: Seismic evidence for a possible deep crustal hot zone beneath Southwest Washington.

A correction to this article has been published and is linked from the HTML version of this paper. The error has beenfixed in the paper.

Seismic evidence for a possible deep crustal hot zone beneath Southwest Washington.

Crustal pathways connecting deep sources of melt and the active volcanoes they supply are poorly understood. Beneath Mounts St. Helens, Adams, and Rainier these pathways connect subduction-induced ascending melts to shallow magma reservoirs. Petrogenetic modeling predicts that when these melts are emplaced as a succession of sills into the lower crust they generate deep crustal hot zones. While these zones are increasingly recognized as a primary site for silicic differentiation at a range of volcanic settings globally, imaging them remains challenging. Near Mount Rainier, ascending melt has previously been imaged ~28 km northwest of the volcano, while to the south, the volcano lies on the margin of a broad conductive region in the deep crust. Using 3D full-waveform tomography, we reveal an expansive low-velocity zone, which we interpret as a possible hot zone, linking ascending melts and shallow reservoirs. This hot zone may supply evolved magmas to Mounts St. Helens and Adams, and possibly Rainier, and could contain approximately twice the melt volume as the total eruptive products of all three volcanoes combined. Hot zones like this may be the primary reservoirs for arc volcanism, influencing compositional variations and spatial-segmentation along the entire 1100 km-long Cascades Arc.

Chromosome microarray analysis in a clinical environment: new perspective and new challenge.

The analysis of the human genome has largely been undertaken in a research environment, but recent developments in technology and associated workflow have allowed diagnostic laboratories to interrogate DNA at significantly improved levels of resolution. Principally, whole genome-based analysis of copy number changes using microarrays has led to this method replacing conventional karyotyping as a routine diagnostic workhorse. The resolution offered by microarrays is an improvement of at least an order of magnitude compared to karyotyping, but it comes at a cost in terms of the time spent in data interpretation. Overall, however, the die has been cast and cytogeneticists need to become familiar with the tools use by molecular geneticists and bioinformaticists. The following review provides a brief background to array technology, but uses a series of case studies to illustrate the usefulness and challenges of interpreting array data.

Molecular characterisation of a der(Y)t(Xp;Yp) with Xp functional disomy and sex reversal.

Sex reversal due to duplication of the Xp21 dosage-sensitive sex reversal locus results in XY females with gonadal dysgenesis. Pure Xp disomy (without a concurrent loss of genetic material) can occur by translocation or interstitial duplication. The case reported here is the rare form with a t(Xp;Yp). The combination of conventional clinical cytogenetic techniques, microsatellite analysis and high-density microarrays identified the X-chromosome breakpoint as centromeric of the NR0B1 gene and its control elements. Cytogenetics and array technology complemented each other in characterizing the translocation event and the extent of the dosage-sensitive sex reversal critical region on the derivative Y-chromosome. The implications of this analysis also lie in genetic counseling that highlight the likely de novo nature of a paternal meiotic event.

Amphidial neurons ADL and ASH initiate sodium dodecyl sulphate avoidance responses in the infective larva of the dog hookworm Anclyostoma caninum.

Ablations of specific amphidial neuron pairs with a laser microbeam were conducted to understand better the neurological basis of the behaviours of larval parasitic nematodes. To date, the functions of the amphidial neurons of Caenorhabditis elegans and their counterparts in parasitic nematodes have been found to be remarkably conserved allowing the possibility to predict the relationships between neurons and their functions. Therefore, we anticipated that ablation of neuron pairs ASH and ASK would abrogate avoidance of sodium dodecyl sulphate (SDS) by infective larvae (L3i) of Anclyostoma caninum. Instead, we have found that laser microbeam ablation of these neuron pairs did not eliminate SDS avoidance in A. caninum, but that neuron pairs ASH and ADL are the amphidial neurons responsible for SDS repulsion. When a droplet of the repellent is placed in the direct path of a normal A. caninum L3i, a strong backward avoidance response is triggered. However, when the ASH and ADL neurons are ablated, the nematodes demonstrate the opposite reaction, increasing their movement in a forward direction.

Vertical migratory behavior of the infective third-stage larvae of Oesophagostomum dentatum.

The vertical migratory behavior of third-stage infective larvae (L3i) of Oesophagostomum dentatum was investigated using upright truncated agarose cones and equivalent conical depressions in agarose. Geotactic response varied with the age of the infective larvae. Four-day-old L3i showed no preference for the sloping surfaces of either indented or upright cones, while the 8-day-old L3i showed a positive geotactic reaction, migrating down the sloping surface of the depressions.

Chemoattraction and chemorepulsion of Strongyloides stercoralis infective larvae on a sodium chloride gradient is mediated by amphidial neuron pairs ASE and ASH, respectively.

Depending on its concentration, sodium chloride acts as either an attractant or a repellant to the infective larvae (L3i) of Strongyloides stercoralis. On a concentration gradient, L3i are attracted to 0.05 M NaCl, but repelled by 2.8M. To test the hypothesis that amphidial neurons ASE and ASH might mediate attraction and repulsion, respectively, these neurons, and control neurons as well, were ablated in hatchling larvae with a laser microbeam. After the larvae attained infectivity (L3i), they were tested on a NaCl gradient. When placed at low salinity, 73.5% of normal controls migrated "up" the gradient, while 26.4% crawled randomly. In contrast, only 20.6% of ASE-ablated L3i migrated "up" the gradient, while 79.4% migrated randomly. Ablation-control ASK-ablated L3i (58.8%) migrated "up" the gradient while 41.1% crawled randomly. When placed at a region of high salinity, 100% of normal control L3i migrated "down" the gradient, whereas 62.5% of ASH-ablated L3i migrated randomly, the remaining 37.5% migrating "down" the gradient. In sharp contrast with ASH-ablated L3i, 94.1% of ablation-control larvae, i.e. ASK-ablated L3i, migrated "down" the gradient. Migration behavior of ASE- and ASH-ablated L3i was significantly different (P < 0.001) from that of ASK-ablated L3i and normal controls. It is noteworthy that 87.5% of ASE-ablated L3i that failed to exhibit chemoattractive behavior were actively chemorepelled from high salinity. Also, 70.0% of ASH-ablated L3i that failed to be chemorepelled from high salinity were capable of chemoattractive behavior, indicating that the worms had retained their behavioral responses except for those associated with the targeted neurons.

The amphidial neuron pair ALD controls the temperature-sensitive choice of alternative developmental pathways in the parasitic nematode, Strongyloides stercoralis.

The parasitic nematode Strongyloides stercoralis, has several alternative developmental pathways. Upon exiting the host (humans, other primates and dogs) in faeces, 1st-stage larvae (L1) can enter the direct pathway, in which they moult twice to reach the infective 3rd-stage. Alternatively, if they enter the indirect pathway, they moult 4 times and become free-living adults. The choice of route depends, in part, on environmental cues. In this investigation it was shown that at temperatures below 34 degrees C the larvae enter the indirect pathway and develop to free-living adulthood. Conversely, at temperatures approaching body temperature (34 degrees C and above), that are unfavorable for the survival of free-living stages, larvae develop directly to infectivity. The time-period within the L1's development during which temperature influenced the choice of the pathway depended on the temperature, but, at any given temperature, occurred approximately in the middle of the time-span spent in the L1 stage, which varied inversely with temperature. This critical period was associated with the time-interval in which the number of cells in the genital primordium began to increase, thus providing a morphological marker for the pathway decision in individual worms. Sensing the environment is the function of the amphidial neurons, and therefore we examined the role of individual amphidial neurons in controlling entry into the direct pathway to infectivity. The temperature-sensitive developmental switch is controlled by the neuron pair ALD (which also controls thermotaxis), as seen by the loss of control when these neurons are ablated. Thus, in S. stercoralis a single amphidial neuron pair controls both developmental and behavioural functions.

Chemotactic behaviour of Strongyloides stercoralis infective larvae on a sodium chloride gradient.

Chemotactic responses of Strongyloides stercoralis infective larvae (L3) to sodium chloride (NaCl) were investigated by recording larval tracks on a saline gradient in agarose. On agarose, larvae migrated randomly, whereas when placed at 0.01 m NaCl larvae moved to approximately 1.1 m NaCl where they turned, headed down the gradient and eventually remained circling at a favoured salinity (0.03-0.07 m). Conversely, when placed at 2.85 m NaCl, the L3 larvae moved unidirectionally to lower, more favoured salt concentrations. Here they circled, changing directions frequently while making 'loop-like' tracks. Larvae were immobilized within 5 min at salt concentrations exceeding 3 m NaCl. When placed at 0.01 m NaCl, 51.1% +/- 26.9 migrated to 1.1 m NaCl after 2 min, and 80% +/- 18.7 did so after 8 min, at an average velocity of 4.1 +/- 1.4 mm/min. Larvae (53.6% +/- 21.6) were repelled from 2.85 m NaCl to lower concentrations after 2 min. After 8 min, 95% +/- 11.1 were repelled, moving at an average velocity of 6.2 +/- 1.1 mm/min. Using this bioassay, the influence of neuronal control over chemotactic behaviour of S. stercoralis and other parasitic nematodes can be elucidated.

Susceptibility of three genetic lines of chicks to infection with a nephropathogenic T strain of avian infectious bronchitis virus.

Mortality rates were compared in three genetic lines of specific pathogen-free chicks inoculated with one of two doses of a nephropathogenic strain of avian infectious bronchitis (IB) virus. The mortality rates were influenced primarily by the chick strain, but also by age and dose of virus. Chicks of the inbred S line were highly susceptible. After inoculation with a low dose of virus at 2 and 4 weeks of age, mortality was 90 and 45%, respectively. Chicks of the HWL non-inbred line were also susceptible, with mortality rates after inoculation at 2 and 4 weeks of age of 70 and 25%, respectively. Chicks of the inbred W line were resistant and non-significant mortality of 10% occurred only in 2-week-old chicks inoculated with a high dose of virus. Viral distribution in tissues of susceptible S and resistant W chicks did not differ, and virus was present in the trachea, lung and kidney of chicks from both lines throughout the acute phase (between days 3 and 7) of infection. Viral titres in the trachea and kidney in susceptible S chicks were slightly but not significantly higher than in the other chicks during the acute phase of infection. Histopathological assessment indicated an earlier onset of a regenerative phase in the trachea of W chicks than in S chicks. S chicks, in contrast to W chicks, showed no signs of renal regeneration. Additionally, the kidneys of S chicks differed from those of W chicks in showing more severe nephritis, more tubular necrosis and less heterophil infiltration and lymphocytic response throughout the acute phase of infection. The results indicate that chicken lines may differ greatly in their susceptibility to fatal IB nephritis and that resistance is likely to be under the control of immune responses to viral infection.

Vertical migration by the infective larvae of three species of parasitic nematodes: is the behaviour really a response to gravity?

Vertical migration by infective larvae (L3) of 3 species of nematodes was investigated. Upright truncated agarose cones were used to test upward migration, and comparable truncated cone-shaped agarose hollows were used to test downward migration. Flat agarose plates were control surfaces. When placed at the bases of upright cones, 74% of Ancylostoma caninum L3 migrated up, whereas only 16.5% migrated down the indented cones; this latter value was not significantly different from larval migration on flat plates. Strongyloides stercoralis L3 also migrated upward in significant numbers (80%). These larvae also failed to migrate downward under normal conditions. However, when the bottoms of the indented cones were 3-5 degrees C warmer than the tops, 75.5% of S. stercoralis L3 migrated down. In contrast, Haemonchus contortus L3 showed no tendency to crawl up or down cones, when compared with normal crawling behaviour on flat plates. Thus, L3 of A. caninum and S. stercoralis exhibited negative geotaxis, crawling against the pull of gravity, while H. contortus did not. The biology of these parasites may explain these behavioural differences.

Factores de riesgo de obesidad infantil / Risk factors for childhood obesity

Se realizó un estudio comparativo, prospectivo y transversal, entre octubre de 1999 a abril 2000 incluyendo niños y adolescentes entre 4 y 16 años que acudieron a consultorio externo del Hospital Garrahan por demanda espontánea, para analizar los factores de riesgo de obesidad infantil. Excluimos a todos aquellos pacientes que presentaban algún tipo de patología crónica que pudiera predisponer a obesidad. Se tomaron dos grupos de pacientes. El primero, pacientes obesos (n=142), y un segundo grupo control de pacientes no obesos (n=100). Se definió como obesidad el índice de masa corporal (I.M.C.) igual o superior al percentilo 85 para edad y sexo. Se detentó que dentro de las variables estudiadas, el número de hijos en la familia, la presencia de padres obesos y las actitudes sedentarias dadas por el alto número de horas de televisión al día y por la falta o escasa actividad física programada, fueron las variables que mostraron mayores diferencias en comparación con pacientes no obesos. Concluimos que la obesidad es una enfermedad que afecta a todo el núcleo familiar, que hace su aparición en la niñez, afecta a hombres y mujeres por igual y se relaciona con actitudes de vida sedentaria.

The panmictic nature of Neisseria meningitidis serogroup B during a period of endemic disease in Canada.

Three hundred and one (301) strains of Neisseria meningitidis serogroup B, isolated from patients with meningococcal disease during the years 1994-1996, were subjected to multilocus enzyme electrophoresis, serotyping, and serosubtyping. Based on the analyses of 14 enzyme loci, 177 electrophoretic types (ETs) were identified. Of these, 136 were represented by single isolates and 41 were represented by multiple isolates (range 2-31). The mean genetic diversity for isolates was 0.444 and for ETs was 0.440. The index of association (I(A)) between loci was 0.530 +/- 0.08 for isolates and 0.256 +/- 0.10 for ETs. Cluster analysis revealed the presence of 39 lineages each represented by a single ET or clusters of ETs. The most common serotypes were 4, 15, and 14 and accounted for 84 (28.0%), 53 (17.6%), and 32 (10.6%) of the isolates, respectively, and were dispersed amongst 46 ETs (1-122), 35 ETs (3-165), and 26 ETs (18-76), respectively. The 109 (36.6%) nontypable (NT) isolates were amongst 74 ETs (6-177). The mean genetic diversity for serotypes 4, 15, and 14 and NT isolates was 0.368, 0.371, 0.343, and 0.442, respectively, and for ETs was 0.363, 0.354, 0.397, and 0.440, respectively. Combinations of serotypes and serosubtypes (number of isolates) that occurred most frequently were 4:P1.14 (17), 14:P1.16 (16), NT:P1.16 (16), 15:P1.16 (13), and NT:P1.13 (13). The majority of group B disease in Canada during 1994-1996 was caused by meningococci of considerable genetic diversity, and reflects a situation of endemic disease. However, the results also indicate that organisms belonging to the ET-5 complex, which has been responsible for outbreaks of group B disease globally for several decades, have been introduced into the country.

Analysis of the function of two circadian-regulated CONSTANS-LIKE genes.

The Arabidopsis genes CONSTANS-LIKE 1 (COL1) and CONSTANS-LIKE 2 (COL2) are predicted to encode zinc finger proteins with approximately 67% amino acid identity to the protein encoded by the flowering-time gene CONSTANS (CO). We show that the circadian clock regulates expression of COL1 and COL2 with a peak in transcript levels around dawn. We analyzed transgenic plants misexpressing COL1, COL2 and CO. Unlike CO, altered expression of COL1 and COL2 in transgenic plants had little effect on flowering time. However, analysis of circadian phenotypes in the transgenic plants showed that over-expression of COL1 can shorten the period of two distinct circadian rhythms. Experiments with the highest COL1 over-expressing line indicate that its circadian defects are fluence rate-dependent, suggesting an effect on a light input pathway(s).