Improving coastal livelihoods through sustainable aquaculture practices - a report to the collaborative APEC Grouper Research and Development Network

Wild-harvest fisheries for live reef fish are largely over-exploited or unsustainable because of over-fishing and the widespread use of destructive fishing practices such as blast and cyanide fishing. Sustainable aquaculture – such as that of groupers – is one option for meeting the strong demand for reef fish, as well as potentially maintaining or improving the livelihoods of coastal communities. This report from a short study by the STREAM Initiative draws on secondary literature, media sources and four diverse case studies from at-risk reef fisheries, to frame a strategy for encouraging sustainable aquaculture as an alternative to destructive fishing practices. It was undertaken as a component of the APEC-funded project Collaborative Grouper Research and Development Network (FWG/01/2001) to better understand how recent technical advances in grouper culture and other complementary work – including that of the Asia-Pacific Marine Finfish Aquaculture Network (APMFAN) hosted by NACA – could better support the livelihoods of poor coastal communities. (PDF contains 49 pages)

Improving aquaculture through increased fisheries extension research

The present study was conducted, as an attempt to disabuse minds of practicing fish farmers and also encourage prospective farmers who are of the opinion that fish culture is not as profitable as it is widely reported. The study was carried out in an abandoned concrete water fountain tank (20m super(2)) made primarily for recreational purposes. The tank was stocked initially with 125 post fingerlings (Heterobtranchus bidorsalis) bought at rate of N30 each. Cost of feeding was N3, 149.85. Gross and net profits for the passive 2- year culture stood at N27, 149.85 and N20, 000.00 respectively. The longest fish (L sub(max)) was 64.0 com TL while the smallest 41.5cm TL (64.8%L sub(max)) and weight 1.9kg (W sub(max)) and 0.5kg 26.3%W sub(max)). Weight and length data generated from the study were examined

Characterization of the human SCF ubiquitin ligases - structure, function, and regulation

<p>The SCF ubiquitin ligase complex of budding yeast triggers DNA replication by cata lyzi ng ubiquitination of the S phase CDK inhibitor SIC1. SCF is composed of several evolutionarily conserved proteins, including ySKP1, CDC53 (Cullin), and the F-box protein CDC4. We isolated hSKP1 in a two-hybrid screen with hCUL1, the human homologue of CDC53. We showed that hCUL1 associates with hSKP1 in vivo and directly interacts with hSKP1 and the human F-box protein SKP2 in vitro, forming an SCF-Iike particle. Moreover, hCUL1 complements the growth defect of yeast CDC53^(ts) mutants, associates with ubiquitination-promoting activity in human cell extracts, and can assemble into functional, chimeric ubiquitin ligase complexes with yeast SCF components. These data demonstrated that hCUL1 functions as part of an SCF ubiquitin ligase complex in human cells. However, purified human SCF complexes consisting of CUL1, SKP1, and SKP2 are inactive in vitro, suggesting that additional factors are required. p> <p>Subsequently, mammalian SCF ubiquitin ligases were shown to regulate various physiological processes by targeting important cellular regulators, like l��B��, β-catenin, and p27, for ubiquitin-dependent proteolysis by the 26S proteasome. Little, however, is known about the regulation of various SCF complexes. By using sequential immunoaffinity purification and mass spectrometry, we identified proteins that interact with human SCF components SKP2 and CUL1 in vivo. Among them we identified two additional SCF subunits: HRT1, present in all SCF complexes, and CKS1, that binds to SKP2 and is likely to be a subunit of SCF5^(SKP2) complexes. Subsequent work by others demonstrated that these proteins are essential for SCF activity. We also discovered that COP9 Signalosome (CSN), previously described in plants as a suppressor of photomorphogenesis, associates with CUL1 and other SCF subunits in vivo. This interaction is evolutionarily conserved and is also observed with other Cullins, suggesting that all Cullin based ubiquitin ligases are regulated by CSN. CSN regulates Cullin Neddylation presumably through CSNS/JAB1, a stochiometric Signalosome subunit and a putative deneddylating enzyme. This work sheds light onto an intricate connection that exists between signal transduction pathways and protein degradation machinery inside the cell and sets stage for gaining further insights into regulation of protein degradation. p>

Paranormal operator on a Hilbert space

<p>In this thesis an extensive study is made of the set P</i> of all paranormal operators in B(H), the set of all bounded endomorphisms on the complex Hilbert space H. T ϵ B(H) is paranormal if for each z contained in the resolvent set of T, d(z, σ(T))//(T-zI)p>-1p> = 1 where d(z, σ(T)) is the distance from z to σ(T), the spectrum of T. P</i> contains the set N of normal operators and P</i> contains the set of hyponormal operators. However, P</i> is contained in L</i>, the set of all T ϵ B(H) such that the convex hull of the spectrum of T is equal to the closure of the numerical range of T. Thus, N≤P</i>≤L</i>.p> <p>If the uniform operator (norm) topology is placed on B(H), then the relative topological properties of N, P</i>, L</i> can be discussed. In Section IV, it is shown that: 1) N P and L</i> are arc-wise connected and closed, 2) N, P, and L</i> are nowhere dense subsets of B(H) when dim H ≥ 2, 3) N = P</i> when dimH ˂ ∞ , 4) N is a nowhere dense subset of P</i> when dimH ˂ ∞ , 5) P</i> is not a nowhere dense subset of L</i> when dimH ˂ ∞ , and 6) it is not known if P</i> is a nowhere dense subset of L</i> when dimH ˂ ∞. p> <p>The spectral properties of paranormal operators are of current interest in the literature. Putnam [22, 23] has shown that certain points on the boundary of the spectrum of a paranormal operator are either normal eigenvalues or normal approximate eigenvalues. Stampfli [26] has shown that a hyponormal operator with countable spectrum is normal. However, in Theorem 3.3, it is shown that a paranormal operator T with countable spectrum can be written as the direct sum, N ⊕ A, of a normal operator N with σ(N) = σ(T) and of an operator A with σ(A) a subset of the derived set of σ(T). It is then shown that A need not be normal. If we restrict the countable spectrum of T ϵ P</i> to lie on a Cp>2p>-smooth rectifiable Jordan curve Gb>ob>, then T must be normal [see Theorem 3.5 and its Corollary]. If T is a scalar paranormal operator with countable spectrum, then in order to conclude that T is normal the condition of σ(T) ≤ Gb>ob> can be relaxed [see Theorem 3.6]. In Theorem 3.7 it is then shown that the above result is not true when T is not assumed to be scalar. It was then conjectured that if T ϵ P</i> with σ(T) ≤ Gb>ob>, then T is normal. The proof of Theorem 3.5 relies heavily on the assumption that T has countable spectrum and cannot be generalized. However, the corollary to Theorem 3.9 states that if T ϵ P</i> with σ(T) ≤ Gb>ob>, then T has a non-trivial lattice of invariant subspaces. After the completion of most of the work on this thesis, Stampfli [30, 31] published a proof that a paranormal operator T with σ(T) ≤ Gb>ob> is normal. His proof uses some rather deep results concerning numerical ranges whereas the proof of Theorem 3.5 uses relatively elementary methods. p>

Some generalizations of commutativity for linear transformations on a finite dimensional vector space

<p>Let L</i> be the algebra of all linear transformations on an n-dimensional vector space V over a field F and let A, B, ƐL</i>. Let Ab>i+1b> = Ab>ib>B - BAb>ib>, i = 0, 1, 2,…, with A = Ab>ob>. Let fb>kb> (A, B; σ) = Ab>2K+1b> - p>σp>1p>Ap>2K-1 p>+p> p>σp>2p>Ap>2K-3 -… +(-1)p>Kp>σb>Kb>Ab>1b> where σ = (σb>1b>, σb>2b>,…, σb>Kb>), σb>ib> belong to F and K = k(k-1)/2. Taussky and Wielandt [Proc. Amer. Math. Soc., 13(1962), 732-735] showed that fb>nb>(A, B; σ) = 0 if σb>ib> is the ip>thp> elementary symmetric function of (βb>4b>- βb>sb>)p>2p>, 1 ≤ r ˂ s ≤ n, i = 1, 2, …, N, with N = n(n-1)/2, where βb>4b> are the characteristic roots of B. In this thesis we discuss relations involving fb>kb>(X, Y; σ) where X, Y Ɛ L</i> and 1 ≤ k ˂ n. We show: 1. If F is infinite and if for each X Ɛ L</i> there exists σ so that fb>kb>(A, X; σ) = 0 where 1 ≤ k ˂ n, then A is a scalar transformation. 2. If F is algebraically closed, a necessary and sufficient condition that there exists a basis of V with respect to which the matrices of A and B are both in block upper triangular form, where the blocks on the diagonals are either one- or two-dimensional, is that certain products Xb>1b>, Xb>2b>…Xb>rb> belong to the radical of the algebra generated by A and B over F, where Xb>ib> has the form fb>2b>(A, P(A,B); σ), for all polynomials P(x, y). We partially generalize this to the case where the blocks have dimensions ≤ k. 3. If A and B generate L</i>, if the characteristic of F does not divide n and if there exists σ so that fb>kb>(A, B; σ) = 0, for some k with 1 ≤ k ˂ n, then the characteristic roots of B belong to the splitting field of gb>kb>(w; σ) = wp>2K+1p> - σb>1b>wp>2K-1p> + σb>2b>wp>2K-3p> - …. +(-1)p>Kp> σb>Kb>w over F. We use this result to prove a theorem involving a generalized form of property L [cf. Motzkin and Taussky, Trans. Amer. Math. Soc., 73(1952), 108-114]. 4. Also we give mild generalizations of results of McCoy [Amer. Math. Soc. Bull., 42(1936), 592-600] and Drazin [Proc. London Math. Soc., 1(1951), 222-231]. p>

Smooth Banach spaces and approximations

<p>If E and F are real Banach spaces let Cp>p,qp>(E, F) O ≤ q ≤ p ≤ ∞, denote those maps from E to F which have p continuous Frechet derivatives of which the first q derivatives are bounded. A Banach space E is defined to be Cp>p,qp> smooth if Cp>p,qp>(E,R) contains a nonzero function with bounded support. This generalizes the standard Cp>p</sup> smoothness classification.p> <p>If an L^p space, p ≥ 1, is Cp>qp> smooth then it is also Cp>q,qp> smooth so that in particular L^p for p an even integer is Cp>∞,∞p> smooth and L^p for p an odd integer is Cp>p-1,p-1p> smooth. In general, however, a Cp>p</sup> smooth B-space need not be Cp>p,p</sup> smooth. Cb>ob> is shown to be a non-Cp>2,2p> smooth B-space although it is known to be Cp>∞p> smooth. It is proved that if E is Cp>p,1p> smooth then Cb>ob>(E) is Cp>p,1p> smooth and if E has an equivalent Cp>p</sup> norm then cb>ob>(E) has an equivalent Cp>p</sup> norm.p> <p>Various consequences of Cp>p,qp> smoothness are studied. If f ϵ Cp>p,qp>(E,F), if F is Cp>p,qp> smooth and if E is non-Cp>p,qp> smooth, then the image under f of the boundary of any bounded open subset U of E is dense in the image of U. If E is separable then E is Cp>p,qp> smooth if and only if E admits Cp>p,qp> partitions of unity; E is Cp>p,p</sup>smooth, p ˂∞, if and only if every closed subset of E is the zero set of some Cp>P</sup> function. p> <p>f ϵ Cp>qp>(E,F), 0 ≤ q ≤ p ≤ ∞, is said to be Cb>p,qb> approximable on a subset U of E if for any ϵ ˃ 0 there exists a g ϵ Cp>p</sup>(E,F) satisfyingp> <p>sup/xϵU, O≤k≤q ‖ Dp>kp> f(x) - Dp>kp> g(x) ‖ ≤ ϵ. p> <p>It is shown that if E is separable and Cp>p,qp> smooth and if f ϵ Cp>qp>(E,F) is Cb>p,qb> approximable on some neighborhood of every point of E, then F is Cb>p,qb> approximable on all of E.p> <p>In general it is unknown whether an arbitrary function in Cp>1p>(l</i>p>2p>, R) is Cb>2,1b> approximable and an example of a function in Cp>1p>(l</i>p>2p>, R) which may not be Cb>2,1b> approximable is given. A weak form of Cb>∞,qb>, q≥1, to functions in Cp>qp>(l</i>p>2p>, R) is proved: Let {Ub>αb>} be a locally finite cover of l</i>p>2p> and let {Tb>αb>} be a corresponding collection of Hilbert-Schmidt operators on l</i>p>2p>. Then for any f ϵ Cp>qp>(l</i>p>2p>,F) such that for all αp> <p>sup ‖ Dp>kp>(f(x)-g(x))[Tb>αb>h]‖ ≤ 1.p> <p>xϵUb>αb>,‖h‖≤1, 0≤k≤qp>

On the Cesari fixed point method in a Banach space

<p>In a paper published in 1961, L. Cesari [1] introduces a method which extends certain earlier existence theorems of Cesari and Hale ([2] to [6]) for perturbation problems to strictly nonlinear problems. Various authors ([1], [7] to [15]) have now applied this method to nonlinear ordinary and partial differential equations. The basic idea of the method is to use the contraction principle to reduce an infinite-dimensional fixed point problem to a finite-dimensional problem which may be attacked using the methods of fixed point indexes.p> <p>The following is my formulation of the Cesari fixed point method:p> <p>Let B be a Banach space and let S be a finite-dimensional linear subspace of B. Let P be a projection of B onto S and suppose Г≤B such that p�� is compact and such that for every x in P��, P<sup>-1p>x∩Г is closed. Let W be a continuous mapping from Г into B. The Cesari method gives sufficient conditions for the existence of a fixed point of W in Г. p> <p>Let I denote the identity mapping in B. Clearly y = Wy for some y in Г if and only if both of the following conditions hold:p> <p>(i) Py = PWy.p> <p>(ii) y = (P + (I - P)W)y.p> <p>Definition. The Cesari fixed paint method applies to (Г, W, P) if and only if the following three conditions are satisfied:p> <p>(1) For each x in P��, P + (I - P)W is a contraction from P<sup>-1p>x∩Г into itself. Let y(x) be that element (uniqueness follows from the contraction principle) of P<sup>-1p>x∩Г which satisfies the equation y(x) = Py(x) + (I-P)Wy(x).p> <p>(2) The function y just defined is continuous from P�� into B.p> <p>(3) There are no fixed points of PWy on the boundary of P��, so that the (finite- dimensional) fixed point index i(PWy, int P��) is defined.p> <p>Definition. If the Cesari fixed point method applies to (Г, W, P) then define i(Г, W, P) to be the index i(PWy, int P��).p> <p>The three theorems of this thesis can now be easily stated.p> <p>Theorem 1 (Cesari). If i(Г, W, P) is defined and i(Г, W, P) ≠0, then there is a fixed point of W in Г.p> <p>Theorem 2. Let the Cesari fixed point method apply to both (Г, W, P<sub>1b>) and (Г, W, P<sub>2b>). Assume that P<sub>2b>P<sub>1b>=P<sub>1b>P<sub>2b>=P<sub>1b> and assume that either of the following two conditions holds:p> <p>(1) For every b in B and every z in the range of P<sub>2b>, we have that ‖b=P<sub>2b>b��� ≤ ‖b-z‖p> <p>(2)P<sub>2b>Г is convex.p> <p>Then i(Г, W, P<sub>1b>) = i(Г, W, P<sub>2b>).p> <p>Theorem 3. If Ω is a bounded open set and W is a compact operator defined on Ω so that the (infinite-dimensional) Leray-Schauder index ib>LSb>(W, Ω) is defined, and if the Cesari fixed point method applies to (Ω, W, P), then i(Ω, W, P) = ib>LSb>(W, Ω).p> <p>Theorems 2 and 3 are proved using mainly a homotopy theorem and a reduction theorem for the finite-dimensional and the Leray-Schauder indexes. These and other properties of indexes will be listed before the theorem in which they are used.p>

A review of IATTC research on the early life history and reproductive biology of scombrids conducted at the Achotines Laboratory from 1985 to 2005

English: For nearly a century, fisheries scientists have studied marine fish stocks in an effort to understand how the abundances of fish populations are determined. During the early lives of marine fishes, survival is variable, and the numbers of individuals surviving to transitional stages or recruitment are difficult to predict. The egg, larval, and juvenile stages of marine fishes are characterized by high rates of mortality and growth. Most marine fishes, particularly pelagic species, are highly fecund, produce small eggs and larvae, and feed and grow in complex aquatic ecosystems. The identification of environmental or biological factors that are most important in controlling survival during the early life stages of marine fishes is a potentially powerful tool in stock assessment. Because vital rates (mortality and growth) during the early life stages of marine fishes are high and variable, small changes in those rates can have profound effects on the properties of survivors and recruitment potential (Houde 1989). Understanding and predicting the factors that most strongly influence pre-recruit survival are key goals of fisheries research programs. Spanish: Desde hace casi un siglo, los científicos pesqueros han estudiado las poblaciones de peces marinos en un intento por entender cómo se determina la abundancia de las mismas. Durante la vida temprana de los peces marinos, la supervivencia es variable, y el número de individuos que sobrevive hasta las etapas transicionales o el reclutamiento es difícil de predecir. Las etapas de huevo, larval, y juvenil de los peces marinos son caracterizadas por tasas altas de mortalidad y crecimiento. La mayoría de los peces marinos, particularmente las especies pel��gicas, son muy fecundos, producen huevos y larvas pequeños, y se alimentan y crecen en ecosistemas acuáticos complejos. La identificación los factores ambientales o biol��gicos más importantes en el control de la supervivencia durante las etapas tempranas de vida de los peces marinos es una herramienta potencialmente potente en la evaluación de las poblaciones. Ya que las tasas vitales (mortalidad y crecimiento) durante las etapas tempranas de vida de los peces marinos son altas y variables, cambios pequeños en esas tasas pueden ejercer efectos importantes sobre las propiedades de los supervivientes y el potencial de reclutamiento (Houde 1989). Comprender y predecir los factores que más afectan la supervivencia antes del reclutamiento son objetivos clave de los programas de investigación pesquera.

Nonpolar m-plane thin film GaN and InGaN/GaN light-emitting diodes on LiAlO2(100) substrates

The nonpolar m-plane (1 (1) over bar 00) thin film GaN and InGaN/GaN light-emitting diodes (LEDs) grown by metal-organic chemical vapor deposition on LiAlO2 (100) substrates are reported. The LEDs emit green light with output power of 80 mu W under a direct current of 20 mA for a 400x400 mu m(2) device. The current versus voltage (I-V) characteristic of the diode shows soft rectifying properties caused by defects and impurities in the p-n junction. The electroluminescence peak wavelength dependence on injection current, for currents in excess of 20 mA, saturates at 515-516 nm. This proves the absence of polarization fields in the active region present in c-plane structures. The light output intensity versus current (L-I) characteristic of the diode exhibits a superlinear relation at low injection current caused by nonradiative centers providing a shunt path and a linear light emission zone at high current level when these centers are saturated. (c) 2007 American Institute of Physics.

Spawning and early development of captive yellowfin tuna (Thunnus albacares)

In this study we describe the courtship and spawning behaviors of captive yellowfin tuna (Thunnus albacares), their spawning periodicity, the influence of physical and biological factors on spawning and hatching, and egg and early-larval development of this species at the Achotines Laboratory, Republic of Panama, during October 1996 through March 2000. Spawning occurred almost daily over extended periods and at water temperatures from 23.3° to 29.7°C. Water temperature appeared to be the main exogenous factor controlling the occurrence and timing of spawning. Courtship and spawning behaviors were ritualized and consistent among three groups of broodstock over 3.5 years. For any date, the time of day of spawning (range: 1330 to 2130 h) was predictable from mean daily water temperature, and 95% of hatching occurred the next day between 1500 and 1900 h. We estimated that females at first spawning averaged 1.6−2.0 years of age. Over short time periods (<1 month), spawning females increased their egg production from 30% to 234% in response to shortterm increases in daily food ration of 9% to 33%. Egg diameter, notochord length (NL) at hatching, NL at first feeding, and dry weights of these stages were estimated. Water temperature was significantly, inversely related to egg size, egg-stage duration, larval size at hatching, and yolksac larval duration.