Farm Household Production Efficiency in Southern Malawi: An Efficiency Decomposition Approach

The present study was set out to estimate production efficiency of tomato (Lycopersicon esculentum L) farmers in the southern region of Malawi’s through efficiency decomposition. A random sample of 72 small-scale farmers was drawn from Balaka district. The findings revealed that farmers in Balaka district have opportunity for productivity gains and cost saving. Mean technical, economic and allocated efficiency were found to be 0.70, 0.57 and 0.82, respectively. Factors like education and credit access augment technical efficiency while credit access, farmer group membership and gender (being male) augment economic and allocative efficiency. Policy thrust like linking small scale farmers to micro-finance institutions for credit access, intensifying family planning programs to reduce family sizes, organizing small scale farmers into groups (cooperatives) and  integrating women into training and extension programs would increase production efficiency of small-scale tomato farming in southern Malawi. Keywords: Decomposition, Malawi, production efficiency, production frontier, tomat

Intracellular calcium movements during relaxation and recovery of superfast muscle fibers of the toadfish swimbladder

© The Author(s), 2014. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Journal of General Physiology 143 (2014): 605-620, doi:10.1085/jgp.201411160.The mating call of the Atlantic toadfish is generated by bursts of high-frequency twitches of the superfast twitch fibers that surround the swimbladder. At 16°C, a calling period can last several hours, with individual 80–100-Hz calls lasting ∼500 ms interleaved with silent periods (intercall intervals) lasting ∼10 s. To understand the intracellular movements of Ca2+ during the intercall intervals, superfast fibers were microinjected with fluo-4, a high-affinity fluorescent Ca2+ indicator, and stimulated by trains of 40 action potentials at 83 Hz, which mimics fiber activity during calling. The fluo-4 fluorescence signal was measured during and after the stimulus trains; the signal was also simulated with a kinetic model of the underlying myoplasmic Ca2+ movements, including the binding and transport of Ca2+ by the sarcoplasmic reticulum (SR) Ca2+ pumps. The estimated total amount of Ca2+ released from the SR during a first stimulus train is ∼6.5 mM (concentration referred to the myoplasmic water volume). At 40 ms after cessation of stimulation, the myoplasmic free Ca2+ concentration ([Ca2+]) is below the threshold for force generation (∼3 µM), yet the estimated concentration of released Ca2+ remaining in the myoplasm (Δ[CaM]) is large, ∼5 mM, with ∼80% bound to parvalbumin. At 10 s after stimulation, [Ca2+] is ∼90 nM (three times the assumed resting level) and Δ[CaM] is ∼1.3 mM, with 97% bound to parvalbumin. Ca2+ movements during the intercall interval thus appear to be strongly influenced by (a) the accumulation of Ca2+ on parvalbumin and (b) the slow rate of Ca2+ pumping that ensues when parvalbumin lowers [Ca2+] near the resting level. With repetitive stimulus trains initiated at 10-s intervals, Ca2+ release and pumping come quickly into balance as a result of the stability (negative feedback) supplied by the increased rate of Ca2+ pumping at higher [Ca2+].This work was supported by a grant to S.M. Baylor from the National Institutes of Health (GM 086167) and a grant to L.C. Rome from the National Science Foundation (IOS-1145981)

Structure of permethyltantalocenephenylmethanecarbothialdehyde hydride, (η^5-C_5Me_5)_2Ta(η^2-SCHCH_2C_6H_5)H

Hydridobis( 7] 5-pentamethylcyclopentadienyl) (phenylmethanecarbothialdehyde-kC,kS)tantalum C_(28)H_(39)STa, Mr= 588.63, monoclinic, P2_1 c, ɑ = 15.729 (5), b = 10.203 (2), c = 17.599 (5) Å, β = 116.18 (2)º , v = 2535 (1) Å^3, z = 4, D_x = 1.54 g cm^(-3), λ(Mo Kɑ) = 0.71073 A, μ = 46.6 cm^(-1), F(000) = 1184, room temperature (297 K), R = 0.068 for 2333 reflections with F_o^2 > 0, R = 0.054 for 2179 with F_o^2 > 3σ(F_o^2). The structure is disordered, with two enantiomeric molecules occupying the same crystallographic site. For the major component, the thioaldehyde ligand has an S-C bond length of 1.86 (2) Å. The ligand is bonded to the Ta center with a Ta-S bond distance of 2.418 (9) Å and a Ta-C bond distance of 2.28 (2) Å

Ovarian antibodies as detected by indirect immunofluorescence are unreliable in the diagnosis of autoimmune premature ovarian failure: a controlled evaluation

BACKGROUND: Ovarian antibodies as detected by indirect immunofluorescence have been used to detect ovarian autoimmunity, but to our knowledge the rate of false positive findings using this method has never been reported. METHODS: Here we examine whether a commercially available ovarian antibody test system, using cynomologous monkey ovary, might be useful in the diagnosis of autoimmune premature ovarian failure. The test was performed in a blinded manner in 26 young women with 46,XX spontaneous premature ovarian failure, in 26 control women with regular menstrual cycles (matched for age, race, and parity) and 26 control men (matched for age and race). We also compared the frequency of other autoantibodies associated with ovarian autoimmunity. RESULTS: As a group young women with premature ovarian failure had an increased incidence of thyroid and gastric parietal cell autoimmunity (p < 0.05). Unexpectedly, however, nearly one third (31%) of normal control women had ovarian antibodies using the commercially available test. One half of young women with premature ovarian failure were found to have ovarian antibodies (P = 0.26). In our own laboratory we found similar results and we were unable to improve the specificity of the test. None of 26 men were found to have ovarian antibodies (P < 0.001). CONCLUSION: Since approximately one third of normal women were found to have ovarian antibodies using the system under study, we conclude that ovarian antibodies as detected by this indirect immunofluorescence method have poor specificity. The specificity of any ovarian antibody test should be established before it is used clinically

U.S. Commission on Immigration Reform

The U.S. Commission on Immigration Reform was created by Congress to assess U.S. immigration policy and make recommendations regarding its implementation and effects. Mandated in the Immigration Act of 1990 to submit an interim report in 1994 and a final report in 1997, the Commission has undertaken public hearings, fact-finding missions, and expert consultations to identify the major immigration-related issues facing the United States today.LBJ School of Public Affair

Space-Time Distribution of G-Band and Ca II H-Line Intensity Oscillations in Hinode/SOT-FG Observations

We study the space-time distributions of intensity fluctuations in 2 - 3 hour sequences of multi-spectral, high-resolution, high-cadence broad-band filtergram images (BFI) made by the SOT-FG system aboard the Hinode spacecraft. In the frequency range 5.5 < f < 8.0 mHz both G-band and Ca II H-line oscillations are suppressed in the presence of magnetic fields, but the suppression disappears for f > 10 mHz. By looking at G-band frequencies above 10 mHz we find that the oscillatory power, both at these frequencies and at lower frequencies too, lies in a mesh pattern with cell scale 2 - 3 Mm, clearly larger than normal granulation, and with correlation times on the order of hours. The mesh pattern lies in the dark lanes between stable cells found in time-integrated G-band intensity images. It also underlies part of the bright pattern in time-integrated H-line emission. This discovery may reflect dynamical constraints on the sizes of rising granular convection cells together with the turbulence created in strong intercellular downflows.Comment: 24 pages, 15 figure

Heterolysis of H−X Bonds by Pentamethylcyclopentadienyl−Aminoborole Complexes of Zirconium and Hafnium

The pentamethylcyclopentadienyl−aminoborole chloro complexes Cp*{η^5-C_4H_4BN(CHMe_2)_2}MCl·LiCl (Cp* = (η^5-C_5Me_5); M = Zr, Hf) heterolytically cleave H−X bonds to form Cp*{η^5-C_4H_4BNH(CHMe_2)_2}MCl(X) (X = OR, SR, C⋮CR). Control experiments using deuterium-labeled substrates show heterolysis occurs with no incorporation of deuterium into the 2,5 positions of the borole heterocycle. Cp*{η^5-C_4H_4BNH(CHMe_2)_2}Hf(C⋮CSiMe_3)_2 is prepared from Cp*{η^^5-C_4H_4BN(CHMe_2)_2}Hf(η^3-C_3H_5) and 2 equiv of (trimethylsilyl)acetylene. Treatment of Cp*{η^5-C_4H_4BN(CHMe_2)_2}MCl·LiCl (M = Zr, Hf) with donor ligands L yields the LiCl-free complexes Cp*{η^5-C_4H_4BN(CHMe_2)_2}MCl(L) (M = Zr, L = NMe2H; M = Hf, L = PMe_3). Cp*{η^5-C_4H_4BN(CHMe_2)_2}HfCl(PMe_3) reacts with (trimethylsilyl)acetylene with loss of HN(CHMe_2)_2 to form Cp*{η^5-C_4H_4B(C⋮CSiMe_3)}HfCl(PMe_3), resulting from formal migration of acetylide from hafnium to boron. X-ray structure determinations of Cp*{η^5-C_4H_4BNH(CHMe_2)_2}HfCl(C⋮CSiMe_3), Cp*{η^5-C_4H_4BN(CHMe_2)_2}HfCl(PMe_3), and Cp*{η^5-C_4H_4B(C⋮CSiMe_3)}HfCl(PMe_3) are reported

Spiky oscillations in NF-kB signalling

The NF-kB signalling system is involved in a variety of cellular processes including immune response, inflammation, and apoptosis. Recent experiments have found oscillations in the nuclear-cytoplasmic translocation of the NF-kB transcription factor. How the cell uses the oscillations to differentiate input conditions and send specific signals to downstream genes is an open problem. We shed light on this issue by examining the small core network driving the oscillations, which, we show, is designed to produce periodic spikes in nuclear NF-kB concentration. The oscillations can be used to regulate downstream genes in a variety of ways. In particular, we show that genes to whose operator sites NF-kB binds and dissociates fast can respond very sensitively to changes in the input signal, with effective Hill coefficients in excess of 20.Comment: 11 pages, 13 figure

Phase Transitions and Vortex Line Entanglement in a Model High Temperature Superconductor

Monte Carlo simulations of the uniformly frustrated 3d XY model are used to model vortex line fluctuations in high temperature superconductors in an applied magnetic field. We find two distinct phase transitions. At a lower T_{c\perp}, the vortex lattice melts and coherence is lost in planes perpendicular to the magnetic field. At a higher T_{cz}, a vortex tangle percolates throughout the system, and coherence is lost parallel to the magnetic field. Cooling below T_{cz}, high energy barriers for vortex line cutting lead to an entangled glassy state. Figures available upon request to [email protected]: 20 pages, 15 figures, RevTex3.0, UR-93-ST0