melting of plagioclase quartz assemblages at 2 kbar water pressure the melting of plagioclase and quartz has been investigated at ph2o 2kb a single crystal of plagioclase was surrounded by quartz powder and water a reaction rim consisting of glass and of an rich plagioclase developed around unchanged starting plagioclase microprobe determinations of melt and coexisting plagioclase compositions reveal a strong fractionation of plagioclase components between melt and new plagioclase for example at 850 c the approximate xan of melt is 0 3 and that of plagioclase is 0 8 the temperature interval between beginning of melting and complete melting of cotectic compositions is 100 c or more for quartz plagioclase mixtures with plagioclases between an 40 and an 75 in comparison to the system ab an h2o the plagioclase melting loop is somewhat wider in the investigated system qz ab an h2o but the temperature interval is much smaller 100 c than in the system ab an h2o 200 c the solidus data indicated by the new plagioclase compositions are practically identical with those observed in beginning of melting experiments the results show that fractionation of plagioclase components between partial melts and restite plagioclase can be more pronounced in multi component rocks than in the pure plagioclase system this finding is important for the development of albite rich rocks from more basic compositions

magma flow directions inferred from preferred orientations of phenocryst in a composite feeder dike miyake jima japan abstract the feeder dike formed by the eruption of the 1983 miyake jima japan is composite based on field observations such as cooling joints and zonal arrangement of it three dimensional orientation measurements on phenocrysts contained in the dike combined with the field observations indicate that the dike was emplaced by three magma pulses the first and second pulses were intruded horizontally the final pulse however was intruded vertically such directional variations are consistent with the eruptive sequence of the active centers observed during the eruption therefore these techniques may be useful to determine the location of old vents and other volcanic structures

cockroaches traverse crevices crawl rapidly in confined spaces and inspire a soft legged robot jointed exoskeletons permit rapid appendage driven locomotion but retain the soft bodied shape changing ability to explore confined environments we challenged cockroaches with horizontal crevices smaller than a quarter of their standing body height cockroaches rapidly traversed crevices in 300 800 ms by compressing their body 40 60 high speed videography revealed crevice negotiation to be a complex discontinuous maneuver after traversing horizontal crevices to enter a vertically confined space cockroaches crawled at velocities approaching 60 cm s 1 despite body compression and postural changes running velocity stride length and stride period only decreased at the smallest crevice height 4 mm whereas slipping and the probability of zigzag paths increased to explain confined space running performance limits we altered ceiling and ground friction increased ceiling friction decreased velocity by decreasing stride length and increasing slipping increased ground friction resulted in velocity and stride length attaining a maximum at intermediate friction levels these data support a model of an unexplored mode of locomotion body friction legged crawling with body drag friction dominated leg thrust but no media flow as in air water or sand to define the limits of body compression in confined spaces we conducted dynamic compressive cycle tests on living animals exoskeletal strength allowed cockroaches to withstand forces 300 times body weight when traversing the smallest crevices and up to nearly 900 times body weight without injury cockroach exoskeletons provided biological inspiration for the manufacture of an origami style soft legged robot that can locomote rapidly in both open and confined spaces

magma flow directions in dikes of the koolau complex oahu determined from magnetic fabric studies we compared the magnetic fabric with the macroscopic surface lineation direction previously assumed to be parallel with magma flow direction for 35 dikes of the koolau complex oahu anisotropy of magnetic susceptibility ams was determined for 530 samples from 59 dikes including a sill and a pluglike intrusive body and two filled lava tubes and statistically significant ams clusters were found in all but five dikes for the 35 lineated dikes the mean maximum ams direction 1 coincides with the macroscopic lineations to within 25 in 18 and to within 15 in eight the ams ellipsoid shape in about half of the samples is prolate cigar shaped and in about half is oblate pancake shaped we interpret the ams to be determined by shape anisotropy of ferromagnetic grains the mean total anisotropy is 2 2 and total anisotropy h ranges from 0 24 to as high as 14 12 the principal ams axes for samples from a dike are tightly grouped on equal area plots and for most of the dikes the minimum ams axes plot near to the pole of the dike our ams measurements enable us to infer absolute magma flow directions for half the dikes studied the maximum ams axes of samples from one side of the dike form a tight cluster on an equal area plot and those from the other side of the dike form another tight cluster the two clusters are close together separated by 10 30 for narrow dikes 100 cm wide and are farther apart 30 60 for wide dikes and are symmetrically disposed on either side of the plane of the dike we infer that these paired clusters are caused by imbrication of nonequant ferromagnetic crystals against each margin of the dike during deposition in a velocity gradient and hence indicate the flow azimuth i e the absolute magma flow direction nearly half of the dikes measured 25 gave paired ams plots in 12 the magma flowed up at low oblique angles 5 30 from the horizontal in five it flowed down at 5 20 in four it flowed horizontally 5 in three it flowed up at a steep angle 50 75 and in one it flowed down at a steep angle the magma flow in general was rarely vertical or horizontal

on the vorticity balance over steep slopes kuroshio intrusions northeast of taiwan abstractthe circulation of the kuroshio northeast of taiwan is characterized by a large anticyclonic loop of surface intrusion and strong upwelling at the shelfbreak to study the mechanisms of kur

progress on upwelling studies in the china seas east asian marginal seas surrounding china exhibit rich ocean upwelling mostly in response to the southwesterly summer monsoon upwelling in the china seas namely the south china sea the taiwan strait the east china sea the yellow sea and the bohai sea has become increasingly important because the potential changes in the upwelling may have dramatic ecosystem socioeconomic and climate impacts this paper reviews the progress of upwelling studies in the china seas since the year 2000 by presenting the principal characteristics and new understanding of 12 major upwelling regions in the china seas upwelling exhibits long term variability at intraseasonal to multi decadal scales as well as short term variability frequently caused by tropical cyclones it is also associated with the el nino southern oscillation local environmental variation and biogeochemical factors the coastal upwelling around hainan island and the upwelling or cold dome northeast of taiwan island are specifically highlighted because they have attracted great interest for decades this paper summarizes upwelling mechanisms in terms of wind topography tide stratification and background flow with applications mostly to the china seas finally we propose some topics for future upwelling research i e potential intensification of coastal upwelling under global climate change downwelling intrusion of upwelling into coastal embayments and the influence of upwelling on fishery and biogeochemical processes

a numerical study on the formation of upwelling off northeast taiwan 1 we examined the spatial and temporal variations of upwelling off northeast taiwan using a fine resolution numerical model with realistic bathymetry the zonally running shelf break in the area deflects the kuroshio seaward and produces upwelling on its on shelf edge the upwelling in turn manifests a cold dome or a cyclonic eddy in depths below 150 m or so the upwelling and hence the cyclonic eddy exist year round above this depth the eddy waxes and wanes as the upper portion of the kuroshio migrates seaward and shoreward respectively the eddy event fluctuates in a wide range of timescales seasonally the occurrence heavily favors summer rather than winter because the mean kuroshio axis migrates seaward in summer intraseasonally the fluctuation contains two dominant periods centered at 70 days and 30 days local wind forcing and channeling by two local canyons do not affect the eddy statistics significantly

effect of bathymetric curvature on gulf stream instability in the vicinity of the charleston bump abstract the effect of the isobathic curvature on the development and evolution of gulf stream frontal waves meanders and eddies in the vicinity of the charleston bump a topographic rise on the upper slope off charleston south carolina referred to as cb hereinafter is studied using the hybrid coordinate ocean model hycom baroclinic and barotropic energy transfers from the gulf stream to its meanders and eddies that appear as cold and warm anomalies are computed for four different cases in case i the curvature of the isobaths is artificially reduced and the cb is removed from the bathymetry in this simulation the simulated gulf stream meanders were barely noticeable in the study region energy transfer from the gulf stream to meanders and eddies was negligible in case ii the curvature of the isobaths was the same as in case i but a bump of the scale of the cb was added to the bathymetry in this simulation gulf stream meanders were amplified while passing over the cb in case iii the cb w

seasonal exchanges of the kuroshio and shelf waters and their impacts on the shelf currents of the east china sea previous in situ observations and modeling studies have indicated that through mass and momentum exchanges across the shelf edge the kuroshio can significantly influence the shelf currents of the east china sea ecs here instead of localized observations this study uses 25yr of drifter data supported by satellite and other data to identify seasonal cross shelf exchanges along the entire shelf edge the authors show that kuroshiomeandersonshorefromfalltowinterandoffshorefromspringtosummer withthelargestamplitude northeast of taiwan the influence is limited to the shelf edge when the kuroshio meanders offshore in spring and summer by contrast strong onshelf intrusions and cross shelf exchanges occur when the kuroshio meanders onshore in fall and winter drifters intrude onshelf northeast of taiwan and spread as far north as 308n against the strong northeasterly wind the forcing on the shelf is identified as a northward downsloping of the sea level that is steepest north of taiwan at 258 288n but which is 3 times weaker farther north the vorticity budget computed from a numerical model indicates that intrusion during fall andwinter is primarily a result of balancebetweenonshelfadvectionofambientpotentialvorticityandvorticityproductionbythealong isobath pressure gradient acting on the changing mass of water column across the continental slope

subterranean ant nests trace fossils past and future many species of ants excavate complex species typical nests in soil the basic structural units of many nests are descending tunnels connecting flattened generally horizontal chambers of oval to lobed outline the species typical structure of many nests results from variation in the size shape number and arrangement of these basic elements nest architecture can be rendered by filling subterranean nests with a thin slurry of orthodontal plaster then excavating and reconstructing the hardened cast photographs of such nest casts of nine species of ants from northern florida show the range and type of variation of architecture preservation conditions under which ant nests could form complex trace fossils are discussed and reports of such traces reviewed the images presented in this paper will help to alert trace fossil specialists to the potential range of appearance of such nest fossils 2002 elsevier science b v all rights reserved

upper ocean currents around taiwan abstract current velocity measured by shipboard acoustic doppler current profiler sb adcp during 1991 2000 was used to study the upper ocean the composite and moored currents revealed a branch of the kuroshio that intruded steadily and persistently into the south china sea part of the intruded kuroshio flowed out of the south china sea through the northern luzon strait and re united with the main stream kuroshio the kuroshio had two velocity maximum cores southeast of taiwan but gradually combined into one as the kuroshio flowed north the kuroshio was deflected by the i lan ridge east of taiwan and the zonal running shelf break northeast of taiwan at the shelf break the kuroshio split with one branch intruding onto the shelf west of the luzon strait the kuroshio intruded into the south china sea some water flowed northward into the taiwan strait and re joined the kuroshio currents in the taiwan strait flowed primarily in a northward direction except for the southward current near the coast of mainland china north of the taiwan strait a branch of the northward flow followed the northern coast of taiwan to join the kuroshio the composite current varied consistently from season to season there was generally poor correlation between currents and local winds especially in the deep water regime remote forces were important in the currents around taiwan

pre eruption history of phyric basalts from dsdp legs 45 and 46 evidence from morphology and zoning patterns in plagioclase phyric basalts recovered from dsdp legs 45 and 46 contain abundant plagioclase phenocrysts which occur as either discrete single grains megacrysts or aggregates glomerocrysts and which are too abundant and too anorthitic to have crystallized from a liquid with the observed bulk rock composition almost all the plagioclase crystals are complexly zoned in most cases two abrupt and relatively large compositional changes associated with continuous internal morphologic boundaries divide the plagioclase crystals into three parts core mantle and rim the cores exhibit two major types of morphology tabular with a euhedral to slightly rounded outline or a skeletal inner core wrapped by a slightly rounded homogeneous outer core the mantle region is characterized by a zoning pattern composed of one to several spikes plateaus superimposed on a gently zoned base line with one large plateau always at the outside of the mantle and by in most cases a rounded internal morphology the inner rim is typically oscillatory zoned the width of the outer rim can be correlated with the position of the individual crystal in the basalt pillow the presence of a skeletal inner core and the concentration of glass inclusions in low an zones in the mantle region suggest that the liquid in which these parts of the crystals were growing was undercooled some amount the resorption features at the outer margins of low an zones indicate superheating of the liquid with respect to the crystal

continuous mixing of crystal mush and replenished magma in the ongoing unzen eruption zoning profiles of magnetite phenocrysts in the successively effused dacite of the ongoing unzen eruption from 1991 wereanalyzed to estimate the time scale of magma mixing the dacite was formed by mixing of relatively high and low temperature t end member magmas the magnetite phenocrysts derived from the low t magma are reversely zoned by the mixing with high t magma a diffusion calculation for reequilibration of the reverse zonings gives the time interval from magma mixing to quenching for the mixed dacite erupted from may 1991 to may 1993 the typical diffusion time was estimated to be a few months regardless of the effused sequence for 2 yr this indicates that the mixing was continuous during the effusion the invariability of the other mixing signatures such as the thickness of reaction rims around biotite phenocrysts also supports the continuous mixing model low t end member magma is estimated by mass balance calculation to be a crystal rich mush of dacitic composition these observations lead to a model wherein the highly crystallized remnant magma of the preceding activity has been mixed with the newly injected hot magma of similar bulk composition just prior to the effusion the proposed mechanism implies that this type of magma mixing is an inevitable process in periodically erupting polygenetic volcanoes

the pattern and variability of winter kuroshio intrusion northeast of taiwan the variations of the kuroshio path and velocity northeast of taiwan are analyzed based on along track satellite altimeter data as well as high resolution model experiments observations reveal that in winter the kuroshio intrusion into the east china sea ecs at this location is manifested by a secondary maximum current core smcc shoreward of the kuroshio s main path the smcc varies significantly on interannual time scale and its variability is strikingly out of phase with that of the kuroshio entering the ecs meaning that the stronger the kuroshio the weaker the smcc and vice versa model experiments corroborate the observational results and more importantly indicate that the kuroshio intrusion here follows two primary routes a large anticyclonic loop that separates from the kuroshio at the northern end of taiwan and moves forward to form the smcc and a straight northward path onto the shelf when the kuroshio turns sharply eastward along the continental slope of the ecs the intrusion is controlled by both local forcing and remote effect with its pattern and variability depending mostly on the local heat flux and the inertia of the kuroshio current

topex poseidon observations of mesoscale eddies over the subtropical countercurrent kinematic characteristics of an anticyclonic eddy and a cyclonic eddy 1 relative dynamic heights and geostrophic fields were derived from topex poseidon altimetry data and then used to track mesoscale eddies over the subtropical countercurrent stcc the radii centers vorticities shearing deformation rates stretching deformation rates divergences and center velocities of all identified eddies over the stcc were determined using a model that assumes constant velocity gradients most eddies are concentrated in a zonal band near 22 n and there is an interannual variation in the number of eddies a case study was made for a cyclonic eddy and an anticyclonic eddy with time series of eddy kinematic parameters computed both eddies survive for 220 days and propagate westward along over 22 n 24 n to reach the kuroshio current east coast of taiwan where the eddies were dissipated and in turn affected the kuroshio current in many ways sea surface temperature data and drifter data confirm the existence of these two eddies the radii of both eddies vary and their shapes are mostly elliptical during propagation the anticyclonic eddy propagated almost westward with oscillating north south components and the mean speed is 8 3 km day the cyclonic eddy moved southwestward before reaching 130 e and then moved northwestward with a mean speed of 7 6 km day the propagations of these two eddies are basically consistent with the standard theory of eddy propagation but with larger speeds the propagating direction could be altered while passing steep bottom topography or merging with the other eddies index terms 4520 oceanography physical eddies and mesoscale processes 4576 oceanography physical western boundary currents 4512 oceanography physical currents 4594 oceanography physical instruments and techniques 4556 oceanography physical sea level variations

continental slope flow northeast of taiwan abstract hydrographic observations and current measurements with a shipboard acoustic doppler current profiler over the continental shelf slope junction northeast of taiwan during 10 17 august 1994 allow the construction of the mesoscale flow pattern generated by the collision of the kuroshio and a stretch of the continental shelf that has turned to run nearly east west the pattern is made up of a deflected kuroshio mainstream to the east an intrusion of kuroshio water onto the continental shelf region a counterclockwise circulation over mien hwa canyon mhc immediately northeast of taiwan a deep southwestward countercurrent along the northern wall of mhc and a seaward outflow of continental shelf water around the northern coast of taiwan the hydrography features a cold dome over the west side of mhc that consisted of subsurface kuroshio water a temperature salinity plot of all the station data shows the incorporation in the neighborhood of taiwan of continental shelf water into the kuroshio

numerical study of the ocean circulation on the east china sea shelf and a kuroshio bottom branch northeast of taiwan in summer using the regional ocean model system the ocean circulation on the east china sea ecs shelf was examined by a fine resolution model which was nested in a coarse resolution pacific ocean model the high resolution simulation shows an accurate volume transport of 2 70 sv sv 10 6 m 3 s 1 through the tsushima strait which is more consistent with the previous 5 5 year observation value 2 64 sv than former model results for the taiwan strait it also shows a close volume transport 1 03 sv to a recent estimate 1 20 sv at the same time the model results reproduced almost all of the known circulation structure on the ecs shelf in addition the hindcast of 2009 shows a kuroshio bottom branch current to the northeast of taiwan kbbcnt the kbbcnt is confirmed by the observational bottom high salinity water from 15 august to 2 september 2009 whose distribution is also reproduced by the model results tracer and particle experiments were carried out to elucidate the formation of the high salinity water and the pathway of the kbbcnt in light of the field observation and numerical experiments a new pathway of the kbbcnt is proposed bifurcated from the subsurface water of kuroshio northeast of taiwan it upwells northwestward gradually from 300 to 60 m then turns to northeast in the region around 27 5 degrees n 122 degrees e and finally reaches 31 degrees n off the mouth of the changjiang river along similar to 60 m isobaths forming the bottom saline water off the coast of zhejiang province china

subvolcanic structure of the central dike swarm associated with the ring complexes in the shitara district central japan the subvolcanic structure of the central dike swarm associated with the miocene otoge ring complex and the shitara igneous complex central japan has been reconstructed the central dike swarm was supplied from several aligned magma reservoirs flow lineations observed at the margin of the dikes converge towards a region that is regarded as a magma reservoir about 1 2 km below present sea level the minimum diameter of the magma reservoir corresponds to the width of the central dike swarm estimated to be about 3 4 km the inferred magma reservoir of the otoge ring complex may have a zoned structure as suggested by the flow lineations of dikes and the arrangement of cone sheets felsic magma occupied the upper part about 1 2 km below present sea level and basic magma the lower part deeper than 2 km the centre of the shitara igneous complex is interpreted to be composed of several other shallow magma reservoirs the distribution pattern in plan view of the central dike swarm is summarized from the frequency of dikes defined by the number of dikes per kilometre in the direction normal to the trend of the dike swarm and the variations of the different properties of individual dikes along the dike swarm it has a plane of symmetry normal to the dike swarm above the magma reservoir the patterns critical to a general understanding of the dike formation are 1 a region of low dike frequency is present above the magma reservoir and a radial dike pattern occurs around the magma reservoir 2 from both sides of the magma reservoir the axes of high dike frequency extend symmetrically along the central zone of the dike swarm 3 the number as well as the individual and total thickness of felsic dikes increases towards the magma reservoir 4 the number of basic dikes increases towards both sides of the magma reservoir while the individual thicknesses of basic dikes increase with distance from the magma reservoir

interannual variability of the kuroshio onshore intrusion along the east china sea shelf break effect of the kuroshio volume transport the interannual variability of the kuroshio onshore intrusion koi across the east china sea ecs shelf break and its response to the ecs kuroshio volume transport kvt during 1993 approximate to 2010 are studied based on a high resolution real time and global ocean general circulation model since variability of kvt is mainly determined in the interior pacific it is rather a remote than a local factor for the local ecs koi on interannual time scales kvt affects koi not only in the net volume transport across the entire shelf break but also in the spatial pattern along the shelf break when kvt increases the intrusion decreases increases upstream downstream of the major intrusion region northeast of taiwan the retreating increases decreases upstream downstream of the main veering region southwest of kyushu these patterns are caused by cyclonic eddies induced by the seaward deflection of the kuroshio axis from the shelf break which ultimately results from the kvt increase a diagnostic mechanism of koi approximate to msin delta h 1 is proposed where h is the bottom depth is the angle between isobaths and the vertically averaged current and m is the absolute volume transport at the shelf break is large in the major intrusion retreating regions and stable on interannual time scales while m changes with opposite signs between upstream and downstream of the major intrusion retreating regions the mechanism explains well the relation of local kvt and the spatial pattern of koi along the shelf break in both the mean state and the interannual variations

seasonal response of the southern east china sea shelf water to wind modulated throughflow in the taiwan strait seasonal change of the southern east china sea ecs shelf water and its relation to the throughflow in the taiwan strait ts was examined based on comparative experiments with inserting passive tracers into a regional ocean model through analyzing the model output results we found that from autumn to winter strong northeasterly wind over the ts significantly weakens the outflow from the ts i e flowing into the ecs and the kuroshio water intrudes farther shoreward across the northern shelf of taiwan in response to the weakened outflow on the other hand water flowing into the shelf from the ts extends further offshore from spring to summer when the ts throughflow is enhanced by a wind change from northeasterly to southwesterly and the kuroshio water retreats seaward off the shelf due to the offshore extension of the shelf water it suggests that the weakening strengthening of the ts throughflow could allow inhibit shelf ward kuroshio water onto the northeastern shelf of taiwan emphasizing that the throughflow modulated by a local wind can be an important factor controlling the seasonal variation of the southern ecs shelf water

why are there upwellings on the northern shelf of taiwan under northeasterly winds upwellings are observed on the northern shelf of taiwan during northeasterly winds analytical and realistic numerical models are used to explain how vertical motions are created by divergence and convergence produced by wind acting on the vorticity field of two strong jets the kuroshio and the taiwan warm current the seaward increase in cyclonic vorticity near the kuroshio s western edge favors a stronger ekman transport away from the jet producing upwelling at the shelfbreak under a northeasterly wind a similar mechanism for generating vertical motions is found across the taiwan warm current the numerical model results indicate that the vorticity effects can account for up to 30 50 of the total variation in the surface ekman transport except during summer s weak southwesterlies northeasterly wind is dominant over the east china sea suggesting that the vorticity effects may be prominent in the observed shelfbreak upwelling in nonsummer months

lagrangian observations of surface flow patterns in the vicinity of taiwan two satellite tracked surface drifters were launched off the southwestern coast of taiwan on october 7 1997 both traveled northward along the taiwan strait ts and into the seas north of taiwan lasting 20 and 53 days respectively from the drifter trajectories their rotary spectra and satellite infrared imagery several oceanic features have been detected and are discussed in this paper our results indicate that in the southern and central portions of the ts the floats followed a northward flow with a mean speed of 30 50 cm s upon reaching the northwestern taiwan coast the trajectories were strongly affected by the semidiurnal tides and interacted with the kuroshio water in the southern east china sea the onset of the strong northeastern winter monsoon in early november decelerated the northward movement and eventually reversed the direction this process was accompanied by wind generated near inertial motion one drifter was then captured by a counterclockwise circulation of a cold dome at the continental shelf break northeast of taiwan finally the drifter was entrained by the mainstream of the kuroshio and flowed towards the northeast

fractionation and magma mixing within intruding dike swarm evidence from the miocene shitara otoge igneous complex central japan abstract the analysis of intrusion pattern and petrological character of the central dike swarm in the miocene igneous complex of the shitara district central japan clarified that magma mixing between a strongly differentiated magma and a less differentiated magma occurred within a dike swarm the dike rocks have a wide compositional variation ranging from 5 5 to 0 7 wt mgo they are divided into p1 and p2 types the p2 type rocks provide many lines of evidence for magma mixing such as reversely zoned phenocrysts bimodal composition distribution and dissolution texture whereas p1 type rocks do not phenocryst compositions of p2 type suggest that the magma mixing occurred between a less fractionated phenocryst poor magma and a strongly fractionated crystal rich magma concentration ratios among incompatible elements show that the mixing end components were derived from a similar parental magma common to p1 type by fractional crystallization in a near closed system the dikes with evidence for the magma mixing p2 type are distributed only in the southern marginal part of the dike swarm whereas p1 type dikes do not show any such localization the distribution and the intrusion direction of the dikes indicate a nearly horizontal outward flow of magmas in the southern part of the dike swarm and accompanied magma mixing in the dike during intrusion the fractionated end component is inferred to be a product of crystal fractionation within small and ephemeral magma pockets in the dike swarm magma mixing is thought to have occurred when a newly intruded dike ruptured the magma reservoir the frequency of magma mixing was controlled mainly by competition between the lifetime of ephemeral magma reservoir and frequency of dike intrusions the condition of magma mixing was satisfied only in the southern part of the dike swarm affected by the preceding volcanic activities

climbing falling and jamming during ant locomotion in confined environments locomotion emerges from effective interactions of an individual with its environment principles of biological terrestrial locomotion have been discovered on unconfined vertical and horizontal substrates however a diversity of organisms construct inhabit and move within confined spaces such animals are faced with locomotor challenges including limited limb range of motion crowding and visual sensory deprivation little is known about how these organisms accomplish their locomotor tasks and such environments challenge human made devices to gain insight into how animals move within confined spaces we study the locomotion of the fire ant solenopsis invicta which constructs subterranean tunnel networks nests laboratory experiments reveal that ants construct tunnels with diameter d comparable to body length l 3 5 0 5 mm ants can move rapidly 9 bodylengths per s within these environments their tunnels allow for effective limb body and antennae interaction with walls which facilitate rapid slip recovery during ascending and descending climbs to examine the limits of slip recovery in artificial tunnels we perform perturbations consisting of rapid downward accelerations of the tunnels which induce falls below a critical tunnel diameter ds 1 31 0 02 l falls are always arrested through rapid interaction of appendages and antennae with tunnel walls to jam the falls ds is comparable to the size of incipient nest tunnels d 1 06 0 23 l supporting our hypothesis that fire ants construct environments that simplify their control task when moving through the nest likely without need for rapid nervous system intervention

seasonal and interannual changes of the kuroshio intrusion onto the east china sea shelf an advanced artificial neural network classification algorithm is applied to 20 years of multisatellite geostrophic velocity data to study the kuroshio intrusion onto the southern shelf of the east china sea the results suggest that the on shelf intrusion may occur year round but winter intrusion events are more frequent than summer events both stronger intrusion which is closely correlated to surface heat flux gradient and weaker intrusion which is correlated to wind forcing occur during wintertime but the former dominates in late winter while the latter prevails in early winter there is a significant year to year variation of the winter on shelf intrusion although on shelf intrusion is the major characteristic of the region during wintertime seldom intrusion events have been identified in the winters of 1997 1998 and 2002 2003 two conditions are responsible for the cause of the nonintrusion events during the two nonintrusion winters the upstream kuroshio transport anomaly is insignificant the kuroshio is not weakened and no significant winter cooling off northeast taiwan thus the kuroshio tends to flow along the shelf break following the 200 m isobath and on shelf intrusion ceases those two nonintrusion events take place during the winters when both the nino 3 4 index and the pdo index are large and positive

fluctuations of the thermal fronts off northeastern taiwan 1 a high resolution sea surface temperature sst data derived from several satellites is used to investigate the variability of the thermal front off northeastern taiwan hidden by a dominant annual cycle the sst data cannot reveal the thermal front fluctuation in the form of hovmoller diagram an innovative methodology has been applied to the sst satellite imagery to derive the sst standardized index sstsi capable of revealing the frontal variability with multiple time scales principal component analysis shows that the sstsi variation consists mainly of two modes mode 1 represents a strong annual cycle related to the seasonal reversal of the monsoonal winds the temperature gradient is enhanced in winter and a cold dome is observed off northern taiwan in summer mode 2 is highly correlated with the upstream kuroshio variability the shoreward seaward migration of the thermal front takes place when the kuroshio transport weakens strengthens the results are consistent with transports estimated by tidal gauge measurements satellite altimeter based sea level anomaly and surface flow patterns derived from high frequency radars mode 2 is coherent with the kuroshio transport through the east taiwan channel at periods of 120 and 45 d with a time lag of 40 and 11 d respectively this 120 d fluctuation is due to the interaction between westward propagating eddies and the kuroshio east of taiwan while the 45 d signal arises from the kuroshio s self instability the interannual variations of the sst pattern in winter and summer are also discussed

undulatory swimming in sand subsurface locomotion of the sandfish lizard the desert dwelling sandfish scincus scincus moves within dry sand a material that displays solid and fluidlike behavior high speed x ray imaging shows that below the surface the lizard no longer uses limbs for propulsion but generates thrust to overcome drag by propagating an undulatory traveling wave down the body although viscous hydrodynamics can predict swimming speed in fluids such as water an equivalent theory for granular drag is not available to predict sandfish swimming speed we developed an empirical model by measuring granular drag force on a small cylinder oriented at different angles relative to the displacement direction and summing these forces over the animal movement profile the agreement between model and experiment implies that the noninertial swimming occurs in a frictional fluid

spatial and temporal variations of the kuroshio east of taiwan 1982 2005 a numerical study 1 a 1 8 east asian marginal seas model nested to a larger domain north pacific ocean model is implemented over a span of 24 years from 1982 to 2005 to investigate the spatial and temporal variations of the kuroshio east of taiwan between 22 and 25 n the mean state and variability of the kuroshio such as the two paths observed in the trajectories of surface drifters southeast of taiwan and the branching of the kuroshio northeast of taiwan are well reproduced by the model southeast of taiwan the kuroshio is mostly in the top 300 m in the inshore path but extends to 600 m in the offshore path northeast of taiwan the kuroshio follows the shelf edge in the east china sea but may branch along a path south of the ryukyu islands the latter path often meanders southward and a significant portion of the kuroshio transport may be diverted to this path the kuroshio extends from the coast to 123 123 5 e between 22 and 25 n with currents reaching a depth of 1000 m at some latitudes the kuroshio transports averaged over five sections east of taiwan are 28 4 5 0 sv and 32 7 4 4 sv with and without the contribution from the countercurrent respectively

dissolution origin and syn entrapment compositional change of melt inclusion in plagioclase abstract in the system di ab an h 2 o melt inclusions in plagioclase were reproducibly formed in a series of partial dissolution experiments and the compositional differences from the surrounding matrix melt were evaluated at 200 mpa and 1050 1150 c a seed crystal of an 59 was partially dissolved into the matrix melt which was in equilibrium with more calcic plagioclase than the seed the reaction proceeded inward from the crystal surface by a dissolution and recrystallization process to form a reaction zone composed of melt channels and recrystallized calcic plagioclase the melt channels were choked necked off by the recrystallized plagioclase at the crystal surface to create melt inclusions the experimentally formed inclusions having square and zigzag shapes up to a few tens of micrometers in size are similar in texture to some common types of natural melt inclusion since the partial dissolution of phenocrysts can occur during various magma mixing processes it should be taken into consideration as one of the inclusion formation mechanisms when trying to interpret information from natural melt inclusions especially for those in hydrous arc magmas the chemical composition of the reproduced melt inclusions deviates from the matrix melt basically along the plagioclase liquidus isotherm the molar ratio of ca ca na and the mgo concentration in the synthesized melt inclusion are up to 17 and 61 relative lower than those in the matrix melt respectively this compositional difference is caused by a combination of factors 1 supersaturation with dissolved plagioclase component 2 insufficient diffusive homogenization in the melt channels due to rapid dissolution of plagioclase and 3 the choking off effect on the basis of the experimental results a model for diffusion in a growing melt channel in dissolving plagioclase was constructed which revealed that the concentration of incompatible elements with low diffusivities can be significantly lower in the melt inclusions than that in the matrix melt these results demonstrate the importance of petrography for interpretation of inclusion data and of more experimental studies on melt inclusion origin

role of the south china sea in regulating the north pacific double gyre system abstractthe role of the south china sea scs in regulating the north pacific circulation is investigated using a two layer quasigeostrophic qg model the double gyre circulations in the north pacific with and without the scs are compared and analyzed it is found that the scs acts as a sink of both potential vorticity pv and energy in the pacific scs system for the mean state consequently the kuroshio and the upstream kuroshio extension ke are weaker in the presence of the scs moreover the eddy activity is also lower in the north pacific ocean because the barotropic instability is suppressed for a weaker circulation in terms of low frequency variations at interannual to decadal time scale the presence of the scs is found to enhance the variability of the latitudinal position and intensity of the ke jet this is explained by a positive feedback process that is associated with the negative correlation between the inertia of the kuroshio and its intrusion into the scs

bimodal behavior of the seasonal upwelling off the northeastern coast of taiwan 1 observations over the outer shelf and shelf break off the northeastern coast of taiwan indicate a curious seasonal variability of upwelling at deeper levels 100 m below the surface upwelling is most intense in summer but weaker in winter nearer the surface at approximately 30 m below the surface the opposite is true and the upwelling is stronger in winter than in summer results from a high resolution numerical model together with observations and simple ekman models are used to explain the phenomenon it is shown that the upwelling at deeper levels 100 m is primarily induced by offshore summer and onshore winter migrations of the kuroshio while monsoonal change in the wind stress curl positive in winter and negative in summer is responsible for the reversal in the seasonal variation of the upwelling near the surface 30 m this mechanism reconciles previous upwelling data

the onshore intrusion of kuroshio subsurface water from february to july and a mechanism for the intrusion variation abstract to examine the variation of kuroshio subsurface water kssw off the coast of zhejiang province china we carried out six monthly cruises from february to july 2015 observations show that the kssw appears in a frequently reported algal bloom area near the coast as early as in april and persists until july however the kssw was absent in february we set up a fine resolution 4 km model which can reproduce most of the observed features model results and cruise data suggest that a nearshore kuroshio branch current nkbc originated from the kssw northeast of taiwan can emerge as early as in april which is responsible for the observed kssw from april to july however in february nkbc turns seaward before reaching this algal bloom area and thus the kssw is absent in addition to the traditional mechanisms of wind bottom stress and cooling we suggest a new mechanism of this nkbc variation in the origin area of the nkbc the kssw is more shoreward squeezed and flows more westward flowing northward in february while northwestward in april in april than february the change of flow direction caused different meeting point between the shelf break and the kuroshio current according to topographic beta spiral different meeting points will induce different upwelling velocity and then contribute to the different intrusion pattern of nkbc this direction change is one of the essential ingredients which enable nkbc to reach as far as the algal bloom area hence algal blooms in april may be potentially influenced by this nkbc whose water properties are significantly different to the coastal water

intrusion of the kuroshio subsurface water in the southern east china sea and its variation in 2014 and 2015 traced by dissolved inorganic iodine species abstract the circulation systems and ecological environment of the east china sea ecs are greatly influenced by the kuroshio the nutrient rich kuroshio subsurface water kssw has been subject to considerable research attention but the intrusion pathway extent and variation of the kssw over the entire southern ecs shelf are still debated in june 2015 the dissolved inorganic iodine species diis were determined and hydrographic data were collected and analyzed in the southern ecs analysis of the collected data suggests that the kssw mainly intrudes onto the ecs shelf from northeast of taiwan and bifurcates into a nearshore branch and an offshore branch the nearshore branch ultimately appears in the subsurface layer within the 50 m isobath off the zhejiang coast north of 30 n and the offshore branch flows along the 100 m isobath and covers the area outside the 80 m isobath another kssw intrusion along the shelf edge is located at 28 n this additional kssw intrusion is weaker and the offshore area in the southern ecs is mainly influenced by the kssw intrusion northeast of taiwan compared with the kssw intrusion on the ecs continental shelf depth

the kuroshio east of taiwan moored transport observations from the woce pcm 1 array observations from the woce pcm 1 moored current meter array east of taiwan for the period september 1994 to may 1996 are used to derive estimates of the kuroshio transport at the entrance to the east china sea three different methods of calculating the kuroshio transport are employed and compared these methods include 1 a direct method that uses conventional interpolation of the measured currents and extrapolation to the surface and bottom to estimate the current structure 2 a dynamic height method in which moored temperature measurements from moorings on opposite sides of the channel are used to estimate dynamic height differences across the current and spatially averaged baroclinic transport profiles and 3 an adjusted geostrophic method in which all moored temperature measurements within the array are used to estimate a relative geostrophic velocity field that is referenced and adjusted by the available direct current measurements the first two methods are largely independent and are shown to produce very similar transport results the latter two methods are particularly useful in situations where direct current measurements may have marginal resolution for accurate transport estimates these methods should be generally applicable in other settings and illustrate the benefits of including a dynamic height measuring capability as a backup for conventional direct transport calculations the mean transport of the kuroshio over the 20 month duration of the experiment ranges from 20 7 to 22 1 sv 1 sv 106 m3 s 1 for the three methods or within 1 3 sv of each other the overall mean transport for the kuroshio is estimated to be 21 5 sv with an uncertainty of 2 5 sv all methods show a similar range of variability of 10 sv with dominant timescales of several months fluctuations in the transport are shown to have a robust vertical structure with over 90 of the transport variance explained by a single vertical mode the moored transports are used to determine the relationship between kuroshio transport and sea level difference between taiwan and the southern ryukyu islands allowing for long term monitoring of the kuroshio inflow to the east china sea

the forcing mechanism leading to the kuroshio intrusion into the south china sea 1 we use a high resolution numerical model to examine the forcing mechanism responsible for kuroshio intrusion into the south china sea scs the collective wisdom is that variations in kuroshio intrusion are closely related to the wind inside or outside the scs a series of experiments was performed to identify the wind related forcing regulating the intrusion the experiments demonstrated that the importance of wind inside the scs is greater than that outside the scs furthermore the northwestward ekman drift due to northeasterly wind in winter intensifies the upstream kuroshio in the luzon strait enhancing the kuroshio intrusion into the scs in particular the wind stress curl wsc off southwest taiwan is chiefly responsible for the kuroshio intrusion both the wsc and intrusion show both seasonal and intraseasonal variation as the negative wsc off southwest taiwan becomes stronger it contributes to anticyclonic circulation the enhanced anticyclonic circulation helps the development of the kuroshio intrusion the consistency between wsc variability and the intrusion suggests that the wsc off southwest taiwan is essential to the kuroshio intrusion variability

satellite views of the episodic terrestrial material transport to the southern okinawa trough driven by typhoon using satellite derived water transparency alias secchi depth images we found clear signals of terrestrial material transport to the southern okinawa trough triggered by the typhoon morakot in august 2009 three sources were identified one is from the eastern coast of taiwan another is from the western coast of taiwan and the other is from the coast of mainland china carried by northward flows typhoon triggered terrestrial materials from both sides of taiwan s coasts were transported to the region northeast of taiwan moreover the terrestrial material from the coast of mainland china could cross the taiwan strait and be further transported to the region northeast of taiwan these typhoon induced terrestrial materials off northeastern taiwan could then be transported to the southern okinawa trough along the western edge of the kuroshio in addition to the particulate terrestrial material transported nutrients might also be transported to the kuroshio main stream a significant phytoplankton bloom was observed along the kuroshio path for about 300 km off northeast of taiwan our results indicate that episodic cyclone driven terrestrial material transport could be another source of mud in the southern okinawa trough

active tails enhance arboreal acrobatics in geckos geckos are nature s elite climbers their remarkable climbing feats have been attributed to specialized feet with hairy toes that uncurl and peel in milliseconds here we report that the secret to the gecko s arboreal acrobatics includes an active tail we examine the tail s role during rapid climbing aerial descent and gliding we show that a gecko s tail functions as an emergency fifth leg to prevent falling during rapid climbing a response initiated by slipping causes the tail tip to push against the vertical surface thereby preventing pitch back of the head and upper body when pitch back cannot be prevented geckos avoid falling by placing their tail in a posture similar to a bicycle s kickstand should a gecko fall with its back to the ground a swing of its tail induces the most rapid zero angular momentum air righting response yet measured once righted to a sprawled gliding posture circular tail movements control yaw and pitch as the gecko descends our results suggest that large active tails can function as effective control appendages these results have provided biological inspiration for the design of an active tail on a climbing robot and we anticipate their use in small unmanned gliding vehicles and multisegment spacecraft

kuroshio subsurface water feeds the wintertime taiwan warm current on the inner east china sea shelf the taiwan warm current twc has an overwhelming influence on the heat salt and nutrients balance on one of the broadest shelf in the world the east china sea shelf in winter the twc flows in an unusual upwind direction and reaches the changjiang yangtze river estuary but its origin and pathway are intensely debated here combined evidences from current measurement hydrographic and stable isotopic data all suggest that the wintertime twc intrusion off the changjiang estuary mainly originates from the kuroshio subsurface water northeast of taiwan rather than from the taiwan strait warm water the kuroshio branched water northeast of taiwan can intrude into the inner shelf near the zhe min coast via bottom layer manifesting by a pronounced boundary at 50 m isobath around 28 n and thereby feeds the twc intrusion into the changjiang estuary the intrusion complicates the hydrological process in the estuary and shelf sea and its impact on marine environment deserves more research attentions

origin of differentiated lavas at kilauea volcano hawaii implications from the 1955 eruption kilauea s 1955 eruption was the first major eruption longer than 2 days on its east rift zone in 115 years it lasted 88 days during which 108 106 m3 of lava was erupted along a discontinuous 15 km long system of fissures a wide compositional range of lavas was erupted including the most differentiated lavas 5 0 wt mgo from a historic kilauea eruption lavas from the first half of the eruption are strongly differentiated 5 0 5 7 wt mgo later lavas are weakly to moderately differentiated 6 2 6 7 wt mgo previous studies using only major element compositions invoked either crystal fractionation macdonald and eaton 1964 or magma mixing wright and fiske 1971 as models to explain the wide compositional variation in the lavas to further evaluate these models detailed petrographic mineralogical and whole rock major and trace element xrf analyses were made of the 1955 lavas plagioclase and clinopyroxene in the early and late lavas show no petrographic evidence for magma mixing olivines from both the early and late lavas show minor resorption which is typical of tholeiitic lavas with low mgo contents core to rim microprobe analyses across olivine augite and plagioclase mineral grains give no evidence of disequilibrium features related to mixing instead plots of an ab vs distance from the core d and fo vs d 4 5 generated essentially linear trends indicative of simple crystal fractionation least squares mass balance calculations for major and trace element data using observed mineral compositions yield excellent results for crystal fractionation sum of residuals squared 0 01 for major elements and 5 for trace elements magma mixing produced less satisfactory results especially for cr furthermore trace element plots of zr vs sr cr and a12o3 generate curved trends indicative of crystal fractionation processes there is no evidence that mixing occurred in the 1955 lavas instead the data are best explained by crystal fractionation involving a reservoir that extends at least 15 km along kilauea s east rift zone a dike was intruded into the rift zone from the summit reservoir eight days after the eruption started instead of causing magma mixing the dike probably acted as a hydraulic plunger forcing more of the stored magma to be erupted