Gatekeeper versus auctioneer: A non-tatonnement result

A non-tatonnement process is described using the simplest demandand-supply model, involving the following: uniformly distributed agents; random matching of buyers and sellers; and a universal permission to engage in mutually acceptable trade at nonequilibrium prices. A sufficient condition is then stated where expected welfare gains are paradoxically greater when the number of market agents is restricted, compared to when all traders are allowed to participate

Heat capacity anomaly at the quantum critical point of the Transverse Ising Magnet CoNb_2O_6

The transverse Ising magnet Hamiltonian describing the Ising chain in a transverse magnetic field is the archetypal example of a system that undergoes a transition at a quantum critical point (QCP). The columbite CoNb$_2$O$_6$ is the closest realization of the transverse Ising magnet found to date. At low temperatures, neutron diffraction has observed a set of discrete collective spin modes near the QCP. We ask if there are low-lying spin excitations distinct from these relatively high energy modes. Using the heat capacity, we show that a significant band of gapless spin excitations exists. At the QCP, their spin entropy rises to a prominent peak that accounts for 30$\%$ of the total spin degrees of freedom. In a narrow field interval below the QCP, the gapless excitations display a fermion-like, temperature-linear heat capacity below 1 K. These novel gapless modes are the main spin excitations participating in, and affected, by the quantum transition.Comment: 14 pages total, 8 figure

Ethylenediamine modified rice hull as a sorbent for the removal of Basic Blue 3 and Reactive Orange 16

The potential of ethylenediamine modified rice hull to remove both basic and reactive dyes from aqueous solutions was studied. Equilibrium sorption data could be fitted into Langmuir and Brunauer-Emmett-Teller isotherm models. Sorption was enhanced by 4.5- and 2.4-fold for Basic Blue 3 and Reactive Orange 16, respectively, in binary dye solutions compared to single dye solutions. Column studies revealed that breakthrough was bed-depth, flow-rate and influent-concentration dependent. Unusual breakthrough curves were obtained for Reactive Orange 16, with very rapid initial breakthrough followed by complete retention at low flow rate, influent concentration and high bed depth. The breakthrough curves of Basic Blue 3 followed the typical S shape of packed-bed systems. Theoretical breakthrough curves at different bed depths and flow rates generated by the two-parameter mathematical model agreed well with the experimental data of single dye solution of Basic Blue 3

Anisotropic effect of field on the orthorhombic-to-tetragonal transition in the striped cuprate (La,Nd)_{2-x}Sr_xCuO_4

The Nd-doped cuprate La_{2-y-x}Nd_ySr_xCuO_4 displays a first-order phase transition at T_d (= 74 K for x=0.10, y = 0.60) to a low-temperature tetragonal (LTT) phase. A magnetic field H applied || the a-axis leads to an increase in T_d, whereas T_d is decreased when H || c. These effects show that magnetic ordering involving both Nd and Cu spins plays a key role in driving the LTO-LTT transition. Related anisotropic effects are observed in the uniform susceptibility and the in-plane magnetoresistance.Comment: 5 pages, 5 figure

KAJIAN KONDISI STOK IKAN SELAR (Selar crumenophthalmus) DI PERAIRAN SERAM BARAT, MALUKU

Selar fish is a potential small pelagic fishery resource in Indonesian territorial waters and is located in Maluku Province, it specially in west seram waters. This research was carried out in the waters of West Seram, Maluku, from March 2018 to February 2019. The objective of research was to study the stock condition of bigeye scad, Selar crumenophthalmus, based on population dynamic from length frequency distribution. Fish samples were collected every month at fish landing from lift net fishers. Totally, there were 1890 individuals collected during the study, excepted June, composed of 925 males and 965 females with the length size ranging from 13.3 cm to 27.2 cm which was composed of 2 and 3 cohorts every month. Condition stock of bigeye scad based on yield per recruit analysis showed that the stock was still below the level of MSY (0.03 of 0.047), obtained from L∞ was 27.40 cm, K was 1.55/yr, Z was 3.66/yr, M was 2.51/yr, F was 1.15/yr, E was 0.32/yr, Lc was 19.92 cm and t0 was -0.10 /yr. This shows that the higher Lc value of selar fish in west seram waters more selective and otherwise.Ikan selar adalah sumberdaya perikanan pelagis kecil yang potensial di perairan teritorial Indonesia dan berada di Provinsi Maluku, khususnya di perairan Seram Barat. Penelitian ini dilakukan di perairan Seram Barat, Maluku, dari bulan Maret 2018 sampai Februari 2019. Tujuan penelitian ini adalah mempelajari kondisi stok ikan Selar (Selar crumenopththalmus) didasarkan pada dinamika populasi dari distribusi frekuensi panjang. Contoh ikan dikoleksi tiap bulan di tempat pendaratan dari nelayan lift net. Total 1890 individu dikoleksi selama penelitian kecuali bulan Juni yang terdiri dari 925 jantan dan 965 betina dengan panjang berkisar dari 13,3 cm sampai 27,2 cm yang terdiri dari 2 dan 3 kelompok umur tiap bulan. Kondisi stok ikan selar didasarkan pada analisis hasil per penambahan individu baru menunjukkan bahwa stok masih di bawah tingkat MSY (0,03 dari 0,047) yang diperoleh dari L∞= 27,40 cm, K= 1,55/yr, Z= 3,66/tahun, M= 2,51/tahun, F= 1,15/tahun, E= 0,32/tahun, Lc (panjang utk pertama kali tertangkap)= 19,92 cm and t0= -0,10/ yr. Hal ini menunjukkan bahwa semakin tinggi nilai Lc ikan selar di Perairan Seram Barat akan semakin selektif dan sebaliknya