Middle Tail Research Articles

Geochemical Characteristics of Primary Halos and Prospecting Significance of the Qulong Porphyry Copper–Molybdenum Deposit in Tibet

The Qulong porphyry copper deposit in Tibet is located in the Tethis–Himalaya metallogenic domain, one of the three major porphyry metallogenic domains in the world. At present, the mining area is mainly used for surface mining. The depth revealed by the drilling project is less than 2 km. The potential for deep resources is unknown. Based on an analysis of the geochemical characteristics of the primary halos around the No. 16 prospecting line, deep extension is discussed in this paper. Studies show that the metallogenic elements are Cu and Mo; the near-ore halo elements are Co, Au, Ag, and W; the supra-ore halo elements are Pb, Zn, Mn, and As; and the sub-ore halo elements are Sn and Bi. According to Gregorian’s zoning index and the barycenter method, the primary halo zoning of the No. 16 exploration line from shallow to deep is Mn–P–Pb–Ni–Zn–V–As–Hg–Co–Au–Cu–W–Ag–Mo–Sb–Sr–Cd–Sn–Ti–Bi. This sequence has a distinct “reverse” zoning feature, indicating that there may be a blind ore body deep in the mine. The geochemical parameter evaluation index based on the element content contrast coefficient suggests that there may be a hidden ore body in the deep. The relative hydrothermal mineralization in the center position of the section may be located deep below the north side of borehole ZK1601-1 in the middle of the section. The ore body erosion parameter model shows that the bottom of the drilling engineering control is the middle tail of the ore body, and there is a certain amount of extension in the deep part. The ideal superimposed model of the primary halo reflects the ore body trend of the 16th line section. The ore body is inclined to the north as a whole; the ore fluid flows from the deep to the southern side of the north side, and the deep part of the northern side of the ore body has a downward trend.

On the asymmetrical connectedness between cryptocurrencies and foreign exchange markets: Evidence from the nonparametric quantile on quantile approach

This study examines the relationship between cryptocurrencies and foreign exchange markets for three digital currencies and six fiat currencies using the quantile on quantile (QQ) regression approach of Sim and Zhou (2015). According to the QQ technique, we estimate how the quantiles of cryptocurrencies affect the foreign exchange market quantiles. It provides a broader view of the entire dependence structure between the forex markets and digital currencies than traditional methods. Our empirical analysis indicates a positive connection between foreign exchange currencies and cryptocurrencies for all nine currencies, particularly Bitcoin, at low, high, and middle tail quantiles. However, differences are present between economies and across quantiles of virtual currencies and fiat currencies for each economy. This heterogeneity is due to variations in economic structure, legal recognition by governments, associated risk, and monetary or macroeconomic policy changes that affect the trading of cryptocurrencies and fiat currencies.

Characteristics of Reconnection Sites and Fast Flow Channels in an MHD Simulation

AbstractWe investigate an interval of moderate magnetic activity from 0–8 UT on 14 March 2008 by using a global magnetohydrodynamics (MHD) simulation with high spatial and temporal resolution. Observations show several distinct substorms during this interval. One of these with onset at 04:44 UT occurs at 04:42 UT in the simulation. The simulation shows reconnection is continuously present at multiple sites. During the growth phase, the number of X‐lines decreases as their total length increase and their locations approach the Earth. The X‐lines create multiple fast flow channels with dipolarization fronts. The total length and area of these channels increase during the growth phase as they penetrate closer to the Earth carrying more magnetic flux. The 04:42 UT onset in the simulation was preceded by the growth of an X‐line that eventually extended 55 RE from 12 RE premidnight to 50 on the dawn side. It produced a narrow flow channel parallel to the X‐line that eventually penetrated inside 10 RE rapidly depositing magnetic flux as the expansion phase developed. Despite this good agreement in expansion phase onset time, ground and satellite observations suggest a quiet growth phase with a sudden onset of reconnection. It may be possible to explain the difference between observations and simulations if all growth phase activity in the simulation maps to the ionosphere at very high latitudes. An auroral streamer at onset maps in the simulation very close to Earth. A recovery phase streamer maps to the middle tail.

Characterization of Pelvic, Foot and Tail Biometrics Using 3D-Kinematic Analysis during The Proestrus-Ovulation Period in Naturally Cycling Primiparous Dairy Cows Housed in a Tie-stall System

ABSTRACT The objective of this study was to investigate 3D-kinematics as a method for determining if primiparous dairy cows display differences in behaviour biometrics during the estrus period as ovulation approaches in a tie-stall system. The second objective was to evaluate the accuracy of behaviour biometrics as estrus alerts. Fourteen primiparous dairy cows (n = 14) were studied as part of a split-plot over time design. 3D-kinematic assessment took place during proestrus-estrus-ovulation period, Follicular diameter, corpus luteum (CL) diameter and estradiol (E2) concentrations served as physiological parameters to indirectly estimate the estrus period (d -1). The frequency of Pelvic tilts, Pelvic shifts left (Pelvicsl), Pelvic shifts right (Pelvicsr), Total pelvic shifts; TPelvicS), Foot strikes left (Foot strike L), Foot strikes right (Foot strike R), and Total feet strikes (TFootS) were recorded. Additionally, the frequency of Micro tail left (TailLMicro), and right (TailRMicro) movements, Middle tail left (TailLMid), and right (TailRMid) movements, Macro tail left (TailLMacro), right (TailRMacro) movements were also recorded. The overall length of estrous cycle in primiparous dairy cows in this study was 21.66 ± 3.09 (LSMeans ± SEM days). The largest Follicular diameter (LSMeans ± SEM; 17.04 ± 0.59 mm) and E2 (17.43 ± 1.76 pg/mL) occurred 24 h before ovulation. The frequency of some behaviour biometrics increased (LSMeans ± SEM Events/5min) at d -2 including Pelvic tilts (19.75 ± 8.67 Events/5min), Pelvicsl (20.26 ± 13.64), and TPelvicS (20.82 ± 8.79) compared to baseline (d -4, Pelvic tilt; 13.10 ± 8.32, Pelvicsl; 3.71 ± 2.52, and TPelvicS; 6.34 ± 2.72). Other significant patterns observed include a decrease at d -1 in the frequency of TFootS (9.86 ± 1.98), TTailMicro (7.30 ± 3.62), TTailMid (1.82 ± 1.01), and TTailMacro (1.66 ± 1.01) movements followed by an increase in frequency at d -4 (TFootS; 14.44 ± 2.78, TTailMicro; 14.57 ± 7.23, TTailMid; 6.07 ± 3.27, and TTailMacro; 1.84 ± 1.12). The accuracy of each behaviour biometric as a potential estrus alert was analyzed using J index values with balance sensitivity – specificity (J index, Se–Sp) levels (ROC curves analysis). Feet strikes had the greatest accuracy (0.50; 0.90-0.6) followed by Pelvic tilts (0.37; 0.78-0.59), Foot strikes L (0.33; 0.44-0.89), TailLMid (0.30; 1.00–0.30), TailLMacro (0.41; 1.0–0.41) and TFootS (0.34; 0.67-0.68). Our results indicate that naturally cycling, primiparous dairy cows housed in tie-stalls exhibit behavioural fluctuations such as the estrus period approaches, which can be used as estrus alerts.

Changing the channel: Digitization and the rise of “middle tail” strategies

AbstractResearch SummaryPrior research has studied whether digitization shifts demand away from mass‐appeal blockbusters toward a “long tail” of existing products. We extend this work by studying whether digitization influences the products created. Using unique data on movies, we examine whether the reduced costs of production and new digital distribution channels spur producers to create products aimed at smaller audiences. We employ a flexible, transparent, and largely graphical empirical approach to document changes unfolding with digitization. We find growth in both intended blockbuster and long tail products, but also, the rise of a “middle tail,” movies distributed via digital channels, with budgets suggesting commercial intent but well below the averages for theatrical distribution. The new middle tail is largely due to newcomers rather than major incumbents.Managerial SummaryDigitization has reduced the costs to create movies, while also enabling new distribution channels that avoid the high costs of theatrical distribution. With lower costs, movies no longer need to be “blockbusters” at the box office to be financially successful. In this article, we study whether digitization has spurred an increase in lower‐budget movies that are not aimed for release in theaters. We find that digitization has unleashed a large number of very low budget movies that attract little commercial attention (i.e., the “long tail”). However, we also find an increase in a new category of movies with budgets between $100,000 and $10 million, aimed at smaller audiences via new digital distribution channels. We show growth in this “middle tail” following digitization.

Contribution of Anisotropic Electron Current to the Magnetotail Current Sheet as a Function of Location and Plasma Conditions

AbstractThe magnetotail current sheet carries the current responsible for the largest fraction of the energy storage in the magnetotail, the magnetic energy in the lobes. It is thus inextricably linked with the dynamics and evolution of many magnetospheric phenomena, such as substorms. The magnetotail current sheet structure and stability depend mostly on the kinetic properties of the plasma populating the magnetotail. One of the most underinvestigated properties of this plasma is electron temperature anisotropy, which may contribute a large fraction of the total current. Using observations from five missions in the magnetotail, we examine the electron temperature anisotropy, Te‖/Te⊥, and its potential contribution to the current density, quantified by the firehose parameter (βe‖−βe⊥)/2, across y∈[−20,20]RE and x∈[−100,−10]RE. We find that a significant fraction (>30%) of all current sheets have an anisotropic electron current density >10% of the total current. These current sheets form two distinct groups: (1) near‐Earth (<30 RE) accompanied by weak plasma flows (<100 km/s) and enhanced equatorial magnetic field (>3 nT) and (2) middle tail (>40 RE) accompanied by fast plasma flows (>300 km/s) and small equatorial magnetic field (≤1 nT). For a significant number of near‐Earth current sheets, the anisotropic electron current can be >25% of the total current density. Our findings suggest that electron temperature anisotropy should be included in current sheet models describing realistic magnetotail structure and dynamics.

Morphometric Differences Between Sexes In the White-Faced Ibis (Plegadis chihi)

ABSTRACT Sexual dimorphism in birds may express itself as differences in body size, plumage, color and/or behavior. Many species are monomorphic in color, which makes sex determination difficult in the field. In order to develop a tool to distinguish between male and female specimens of the White-faced Ibis, Plegadis chihi, by using external body measurements, the objective of this work was to quantify morphometric differences between sexes in adults of this species. The following variables were measured: culmen length, bill height and width, tarsus length, middle toe (with claw) length, wing chord, tail length and body mass. Males were larger than females in all of these variables, and presented statistically significant differences for six out of eight parameters. Three discriminant classification functions were obtained with an accurate total classification rate in >85% of the cases. The length of the culmen, tarsus, middle toe with claw, and wing chord, were among the most useful variables to discrimi...

Behavior of fast earthward flow near the braking region: Hall MHD simulation

Behavior of the fast earthward flow near the braking region in the magnetotail during a substorm is investigated using the Hall MHD simulation. The results indicate that the high-speed earthward plasma flow is associated with fast reconnection in the middle tail. The fast flow is mainly confined in the range . In the region of , due to intermittent magnetic reconnection, the earthward flow exhibits a fluctuating property, i.e., the flow is localized in space and is bursty in time. The pile-up of the magnetic flux and plasma in the near-Earth region leads to formation of the fast-flow braking region or dipolarization front. After colliding into the fast-flow braking region, a part of the Earth flow bounces back, and leads to an intermittent tailward flow in the near-Earth magnetotail.

Current sheet flapping in the near-Earth magnetotail: peculiarities of propagation and parallel currents

Abstract. We consider series of tilted current sheet crossings, corresponding to flapping waves in the near-Earth magnetotail. We analyse Cluster observations from 2005 to 2009, when spacecraft visited the magnetotail neutral plane near X ∈ [ − 17, − 8], Y ∈ [ − 16, − 2] RE (in the GSM system). Large separation of spacecraft allows us to estimate both local and global properties of flapping current sheets. We find significant variation in flapping wave direction of propagation between the middle tail and flanks. Th series of tilted current sheets represent the system of periodic, almost parallel currents with typical thickness of current filaments about L = 0.4 RE. The earthward gradients of Bz magnetic field are reduced within this current system in comparison with the gradients in the quiet near-Earth magnetotail. The wavelength (i.e. a distance between two crossings of current sheets with the same orientations) of the flapping waves is larger than 2πL for most of observations. The velocity of flapping wave propagation is about ion bulk velocity and is significantly lower than the velocity of ion drift relative to electrons. We discuss possible drivers of flapping and estimate the amplitude of the total parallel current generated by flapping waves.

In situ magnetotail magnetic flux calculation

Abstract. We explore two new modifications of the magnetotail magnetic flux (F) calculation algorithm based on the Petrinec and Russell (1996) (PR96) approach of the tail radius determination. Unlike in the PR96 model, the tail radius value is calculated at each time step based on simultaneous magnetotail and solar wind observations. Our former algorithm, described in Shukhtina et al. (2009), required that the "tail approximation" requirement were fulfilled, i.e., it could be applied only tailward x ∼ −15 RE. The new modifications take into account the approximate uniformity of the magnetic field of external sources in the near and middle tail. Tests, based on magnetohydrodynamics (MHD) simulations, show that this approach may be applied at smaller distances, up to x ∼ −3 RE. The tests also show that the algorithm fails during long periods of strong positive interplanetary magnetic field (IMF) Bz. A new empirical formula has also been obtained for the tail radius at the terminator (at x = 0) which improves the calculations.

Morphological properties of the last primaries, the tail feathers, and the alulae of Accipiter nisus, Columba livia, Falco peregrinus, and Falco tinnunculus.

We investigated the mechanical properties (Young's modulus, bending stiffness, barb separation forces) of the tenth primary of the wings, of the alulae and of the middle tail feathers of Falco peregrinus. For comparison, we also investigated the corresponding feathers in pigeons (Columba livia), kestrels (Falco tinnunculus), and sparrowhawks (Accipiter nisus). In all four species, the Young's moduli of the feathers ranged from 5.9 to 8.4 GPa. The feather shafts of F. peregrinus had the largest cross-sections and the highest specific bending stiffness. When normalized with respect to body mass, the specific bending stiffness of primary number 10 was highest in F. tinnunculus, while that of the alula was highest in A. nisus. In comparison, the specific bending stiffness, measured at the base of the tail feathers and in dorso-ventral bending direction, was much higher in F. peregrinus than in the other three species. This seems to correlate with the flight styles of the birds: F. tinnunculus hovers and its primaries might therefore withstand large mechanical forces. A. nisus has often to change its flight directions during hunting and perhaps needs its alulae for this maneuvers, and in F. peregrinus, the base of the tail feathers might need a high stiffness during breaking after diving.

Failure Analysis and its Numerical Simulation on Impact-Damage Rock

Stress wave propagation effect and failure characteristics were studied by one-stage light-gas gun induced-plate impact experiment technology on limestone. The results show that dispersion effect and attenuation character are existed in impacting rock; failure division properties are analyzed by splitting cut observation, the results show that the failure specimen can be divided by three different failure divisions which are head failure zone, middle tension-compression failure zone and tail fracture failure zone. On this basis, impact-damaged process of rock is numerically simulated to analyze impact-damaged mechanism of limestone specimens.

Cluster observations of ∂Bz/∂x during growth phase magnetotail stretching intervals

We study a statistics of ∂Bz/∂x in a thin stretching current sheet (substorm growth phases) observed by Cluster between 8 and 18 RE downtail. After 2005, spacecraft separation allowed to measure directly this derivative of Bz along the tail axis. The near‐tail events (within 14 RE) exhibited a straight decrease of an initially large positive ∂Bz/∂x to ∼1–2 nT/RE. In the more stretched middle tail, usually the small |∂Bz/∂x|<0.5−1 nT/RE had no clear trend and fluctuated around zero with time scales 5–15 min. In general, negative ∂Bz/∂x were ubiquitous. At some onsets, larger negative ∂Bz/∂x<−1 nT/RE were associated with transient dipolarizations, propagating earthward. There was no clear association of local plasma sheet activity onset with any value of ∂Bz/∂x. We discuss relation of observations and recent modeling results.

Dynamical response of the magnetotail to changes of the solar wind direction: an MHD modeling perspective

Abstract. We performed global MHD simulations to investigate the magnetotail response to the solar wind directional changes (Vz-variations). These changes, although small, cause significant variations of the neutral sheet shape and location even in the near and middle tail regions. They display a complicated temporal response, in which ~60 to 80% of the final shift of the neutral sheet in Z direction occurs within first 10–15 min (less for faster solar wind), whereas a much longer time (exceeding half hour) is required to reach a new equilibrium. The asymptotic equilibrium shape of the simulated neutral sheet is consistent with predictions of Tsyganenko-Fairfield (2004) empirical model. To visualize a physical origin of the north-south tail motion we compared the values of the total pressure in the northern and southern tail lobes and found a considerable difference (10–15% for only 6° change of the solar wind direction used in the simulation). That difference builds up during the passage of the solar wind directional discontinuity and is responsible for the vertical shift of the neutral sheet, although some pressure difference remains in the near tail even near the new equilibrium. Surprisingly, at a given tailward distance, the response was found to be first initiated in the tail center (the "leader effect"), rather than near the flanks, which can be explained by the wave propagation in the tail, and which may have interesting implications for the substorm triggering studies. The present results have serious implications for the data-based modeling, as they place constraints on the accuracy of tail magnetic configurations to be derived for specific events using data of multi-spacecraft missions, e.g. such as THEMIS.

The magnetospheric boundary motion during the main phase of the moderate magnetic storm (case study)

As a result of ICME interaction with magnetosphere the negative sudden impulse Si and substorm event were followed. The simultaneous plasma and magnetic field measurements near the magnetospheric boundary (INTERBALL-1), in the nearest magnetotail (GOES 8, 9), in the middle tail (GEOTAIL), in solar wind (WIND), and ground based data were compared to trace the time sequence of events. It was shown that negative sudden impulse Si was observed by ground stations and at geosynchronous altitudes. The character of magnetic field variations that were observed by GOES 9 permit to suggest that compression/expansion wave was propagated inside the magnetosphere. The time sequence of events observed during substorm development pointed that substorm has begun from auroral breakup. The cross current disruption in the nearest tail and neutral line formation in the middle tail occurred almost simultaneously, but some time after auroral breakup. It is possible that both processes associated with releasing of stored energy during substorm were occurred independently in this substorm event. By using an empirical magnetopause model [Shue et al., 1998. Magnetopause location under extreme solar wind conditions. J. Geophys. Res. 103, 17691], the amplitude of magnetopause motion was evaluated. During substorm evolution the amplitude of the magnetopause motion was ∼ 2 –3 Re. The excitation of Kelvin-Helmholtz instability can explain only a few magnetopause crossings.

Report from scientific sessions at the 35 th COSPAR scientific assembly, Paris 2004

As a result of ICME interaction with magnetosphere the negative sudden impulse Si and substorm event were followed. The simultaneous plasma and magnetic field measurements near the magnetospheric boundary (INTERBALL-1), in the nearest magnetotail (GOES 8, 9), in the middle tail (GEOTAIL), in solar wind (WIND), and ground based data were compared to trace the time sequence of events. It was shown that negative sudden impulse Si was observed by ground stations and at geosynchronous altitudes. The character of magnetic field variations that were observed by GOES 9 permit to suggest that compression/expansion wave was propagated inside the magnetosphere. The time sequence of events observed during substorm development pointed that substorm has begun from auroral breakup. The cross current disruption in the nearest tail and neutral line formation in the middle tail occurred almost simultaneously, but some time after auroral breakup. It is possible that both processes associated with releasing of stored energy during substorm were occurred independently in this substorm event. By using an empirical magnetopause model [Shue et al., 1998. Magnetopause location under extreme solar wind conditions. J. Geophys. Res. 103, 17691], the amplitude of magnetopause motion was evaluated. During substorm evolution the amplitude of the magnetopause motion was ∼2–3 Re. The excitation of Kelvin-Helmholtz instability can explain only a few magnetopause crossings.

Average characteristics of the midtail plasma sheet in different dynamic regimes of the magnetosphere

Abstract. We study average characteristics of plasma sheet convection in the middle tail during different magnetospheric states (Steady Magnetospheric Convection, SMC, and substorms) using simultaneous magnetotail (Geotail, 15-35 RE downtail) and solar wind (Wind spacecraft) observations during 3.5 years. (1) A large data set allowed us to obtain the average values of the plasma sheet magnetic flux transfer rate (Ey and directly compare it with the dayside transfer rate (Emod for different magnetospheric states. The results confirm the magnetic flux imbalance model suggested by Russell and McPherron (1973), namely: during SMC periods the day-to-night flux transport rate equals the global Earthward plasma sheet convection; during the substorm growth phase the plasma sheet convection is suppressed on the average by 40%, whereas during the substorm expansion phase it twice exceeds the day-to-night global flux transfer rate. (2) Different types of substorms were revealed. About 1/3 of all substorms considered displayed very weak growth in the tail lobe magnetic field before the onset. For these events the plasma sheet transport was found to be in a balance with the day-to-night flux transfer, as in the SMC events. However, the lobe magnetic field value in these cases was as large as that in the substorms with a classic growth phase just before the onset (both values exceed the average level of the lobe field during the SMC). Also, in both groups similar configurational changes (magnetic field stretching and plasma sheet thinning) were observed before the substorm onset. (3) Superimposed epoch analysis showed that the plasma sheet during the late substorm recovery phase has the characteristics similar to those found during SMC events, the SMC could be a natural magnetospheric state following the substorm.

Relationships among carcass composition and tail measurements in fat-tailed Barbarine sheep

A total of 1392 records collected on 87 Barbarine fat-tailed lambs was used to predict in vivo carcass composition (tail fat, body fat and body muscle) from body weight (BW) and some fat-tail measurements. Lambs were 4–12 months old and weighed 21–48 kg. Measurements included body weight, upper and middle tail-depth, upper and middle tail-width, upper and middle tail-circumference and tail-length. After slaughter, omental, mesenteric, tail and dissected fat in the carcass were separated and weighted. Total body fat (TBF) corresponds to the sum of these fat depots. Weight of tail fat and TBF varied from 0.18 to 2.23 kg and from 0.98 to 7.63 kg, respectively and were highly correlated ( r=0.91; P<0.01) as well with all tail measurements. The highest correlations ( r>0.8) were observed between all fat depots and circumference measures. The best accuracy was obtained in the prediction of tail fat and TBF from circumference of upper and middle tail, width measure and BW (R.S.D.=219 and 611 g, respectively; P<0.01). This study showed that body fat could be predicted in vivo using simple tail measurements in the Barbarine fat-tailed lambs.

Inconsistency of magnetic field and plasma velocity variations in the distant plasma sheet: Violation of the “frozen-in” criterion?

Measurements of the magnetic field and low energy plasma by the GEOTAIL spacecraft have been used to study the relationship between variations of the plasma velocity and of the magnetic field in the distant (100–200 R E ) and middle (40–80 R E ) tail. The analysis was carried out separately for the tail lobes and the plasma sheet. It is shown that the absolute values of the magnetic field and plasma velocity, as well as their corresponding components ( V X and B X , V Y and B Y , V Z and B Z ), are linearly connected in the tail lobes. In the plasma sheet, however, the plasma velocity and the magnetic field do not seem to be related to one another. The distant plasma sheet seems to be in a regime of turbulence. The diffusion coefficients estimated from our data set of the velocity parameters in the plasma sheet are in good agreement with the theoretical predictions of Antonova and Ovchinnikov (1996, 1999).

Model of vortex tubes in the low-latitude plasma sheet of the earth magnetosphere

Theoretical model is proposed to explain specific features of compressional waves of the Pc 4–5 frequency range which were observed with the INTERBALL-1 probe in the middle tail of the Earth magnetosphere. The waves exhibit anti-phase disturbances in thermal plasma and magnetic field pressures. Large-scale vortical plasma motions are associated with the waves. Coupling of the drift Alfven and magnetosonic waves is considered with inclusion of finite plasma compressibility and disturbances along the local magnetic field line. In limiting cases derived equations are reduced to well-known Kadomtsev-Pogutse and Hasegawa-Mima equations. Partial solutions take form of vortices. According to proposed model, two-dimensional vortical motion of a plasma transversely to the local field line is accompanied by nonlinear magnetosonic waves propagating in flux tubes almost along the field lines.