The existence of gonadotropin-releasing hormone-like peptides in the neural ganglia and ovary of the abalone, Haliotis asinina L.

Gonadotropin-releasing hormone (GnRH) is a neuropeptide that is conserved in both vertebrate and invertebrate species. In this study, we have demonstrated the presence and distribution of two isoforms of GnRH-like peptides in neural ganglia and ovary of reproductively mature female abalone, Haliotis asinina, using immunohistochemistry. We found significant immunoreactivities (ir) of anti-lamprey(I) GnRH-III and anti-tunicate(t) GnRH, but with variation of labeling intensity by each anti-GnRH type. IGnRH-III-ir was detected in numerous type1 neurosecretory cells (NS1) throughout the cerebral and pleuropedal ganglia, whereas tGnRH-I-ir was detected in only a few NS1 cells in the dorsal region of cerebral and pleuropedal ganglia. In addition, a small number of type2 neurosecretory cells (NS2) in cerebral ganglion showed lGnRH-III-ir. Long nerve fibers in the neuropil of ventral regions of the cerebral and pleuropedal ganglia showed strong tGnRH-I-ir. In the ovary, lGnRH-III-ir was found primarily in oogonia and stage I oocytes, whereas tGnRH-ir was observed in stage I oocytes and some stage II oocytes. These results indicate that GnRH produced in neural ganglia may act in neural signaling. Alternatively, GnRH may also be synthesized locally in the ovary where it could induce oocytes development.

Evidence for the existence of Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) with and without abdominal discomfort (irritable bowel) syndrome.

There is evidence that Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) is accompanied by gastro-intestinal symptoms; and IgA and IgM responses directed against lipopolysaccharides (LPS) of commensal bacteria, indicating bacterial translocation.

Morphological and molecular investigations of the holocephalan elephant fish nephron: the existence of a countercurrent-like configuration and two separate diluting segments in the distal tubule

In marine cartilaginous fish, reabsorption of filtered urea by the kidney is essential for retaining a large amount of urea in their body. However, the mechanism for urea reabsorption is poorly understood due to the complexity of the kidney. To address this problem, we focused on elephant fish (Callorhinchus milii) for which a genome database is available, and conducted molecular mapping of membrane transporters along the different segments of the nephron. Basically, the nephron architecture of elephant fish was similar to that described for elasmobranch nephrons, but some unique features were observed. The late distal tubule (LDT), which corresponded to the fourth loop of the nephron, ran straight near the renal corpuscle, while it was convoluted around the tip of the loop. The ascending and descending limbs of the straight portion were closely apposed to each other and were arranged in a countercurrent fashion. The convoluted portion of LDT was tightly packed and enveloped by the larger convolution of the second loop that originated from the same renal corpuscle. In situ hybridization analysis demonstrated that co-localization of Na(+),K(+),2Cl(-) cotransporter 2 and Na(+)/K(+)-ATPase α1 subunit was observed in the early distal tubule and the posterior part of LDT, indicating the existence of two separate diluting segments. The diluting segments most likely facilitate NaCl absorption and thereby water reabsorption to elevate urea concentration in the filtrate, and subsequently contribute to efficient urea reabsorption in the final segment of the nephron, the collecting tubule, where urea transporter-1 was intensely localized.

Beyond indifferent players: on the existence of prisoners dilemmas in games with amicable and adversarial preferences

Why don’t agents cooperate when they both stand to gain? This question ranks among the most fundamental in the social sciences. Explanations abound. Among the most compelling are various configurations of the prisoner’s dilemma (PD), or public goods problem. Payoffs in PD’s are specified in one of two ways: as primitive cardinal payoffs or as ordinal final utility. However, as final utility is objectively unobservable, only the primitive payoff games are ever observed. This paper explores mappings from primitive payoff to utility payoff games and demonstrates that though an observable game is a PD there are broad classes of utility functions for which there exists no associated utility PD. In particular we show that even small amounts of either altruism or enmity may disrupt the mapping from primitive payoff to utility PD. We then examine some implications of these results.

A simple demonstration of the existence of the jordan canonical form for any square matrix

All the demonstrations known to this author of the existence of the Jordan Canonical Form are somewhat complex - usually invoking the use of new spaces, and what not. These demonstrations are usually too difficult for an average Mathematics student to understand how he or she can obtain the Jordan Canonical Form for any square matrix. The method here proposed not only demonstrates the existence of such forms but, additionally, shows how to find them in a step by step manner. I do not claim that the following demonstration is in any way “elegant” (by the standards of elegance in fashion nowadays among mathematicians) but merely simple (undergraduate students taking a fist course in Matrix Algebra would understand how it works).

Evaluating the existence of structural change in the brazilian term structure of interest: evidence based on cointegration models with structural break

This paper investigates whether there is evidence of structural change in the Brazilian term structure of interest rates. Multivariate cointegration techniques are used to verify this evidence. Two econometrics models are estimated. The rst one is a Vector Autoregressive Model with Error Correction Mechanism (VECM) with smooth transition in the deterministic coe¢ cients (Ripatti and Saikkonen [25]). The second one is a VECM with abrupt structural change formulated by Hansen [13]. Two datasets were analysed. The rst one contains a nominal interest rate with maturity up to three years. The second data set focuses on maturity up to one year. The rst data set focuses on a sample period from 1995 to 2010 and the second from 1998 to 2010. The frequency is monthly. The estimated models suggest the existence of structural change in the Brazilian term structure. It was possible to document the existence of multiple regimes using both techniques for both databases. The risk premium for di¤erent spreads varied considerably during the earliest period of both samples and seemed to converge to stable and lower values at the end of the sample period. Long-term risk premiums seemed to converge to inter-national standards, although the Brazilian term structure is still subject to liquidity problems for longer maturities.

Existence of nash equilibrium in competitive nonlinear pricing games with adverse selection

We show that for a large class of competitive nonlinear pricing games with adverse selection, the property of better-reply security is naturally satisfied - thus, resolving via a result due to Reny (1999) the issue of existence of Nash equilibrium for a large class of competitive nonlinear pricing games.

Dynamics at infinity and the existence of singularly degenerate heteroclinic cycles in the Lorenz system

In this paper, by using the Poincare compactification in R(3) we make a global analysis of the Lorenz system, including the complete description of its dynamic behavior on the sphere at infinity. Combining analytical and numerical techniques we show that for the parameter value b = 0 the system presents an infinite set of singularly degenerate heteroclinic cycles, which consist of invariant sets formed by a line of equilibria together with heteroclinic orbits connecting two of the equilibria. The dynamical consequences related to the existence of such cycles are discussed. In particular a possibly new mechanism behind the creation of Lorenz-like chaotic attractors, consisting of the change in the stability index of the saddle at the origin as the parameter b crosses the null value, is proposed. Based on the knowledge of this mechanism we have numerically found chaotic attractors for the Lorenz system in the case of small b > 0, so nearby the singularly degenerate heteroclinic cycles.

Electronic spectra, ESR and crystal structure of tetrahedral halocuprates(II). The existence of cations (2tbpo·H+) with a very short hydrogen bond

Two compounds [2tbpo·H+)2[CuCl4]= (yellow) and (2tbpo·H+)2[CuBr4]= (dark purple) (tbpo = tribenzylphosphine oxide) have been prepared and investigated by means of crystal structure, electronic, vibrational and ESR spectra. The crystal structure of the (2tbpo·H+)2[CuCl4]= complex was determined by three-dimensional X-ray diffraction. The compound crystallizes in the space group P42/n with unit-cell dimensions a = 19.585(2), c = 9.883(1)Å, V = 3790 (1)Å3, Z = 2, Dm = 1.303 (flotation) Dx = 1.302 Mg m-3. The structure was solved by direct methods and refined by blocked full-matrix least-squares to R = 0.053 for 2583 observed reflections. Cu(II) is coordinated to four chlorides in a tetrahedral arrangement. Tribenzylphosphine oxide molecules, related by a centre of inversion, are connected by a short hydrogen bridge. Chemical analysis, electronic and vibrational spectra showed that the bromide compound is similar to the chloride one and can be formulated as (2tbpo·H+)2[CuBr4]=. The position of the dd transition bands, the charge transfer bands, the ESR and the vibrational spectra of both complexes are discussed. The results are compared with analogous complexes cited in the literature. © 1983.

Existence of Lagrangians for the Yang-Mills equations

The Yang-Mills equations only admit a Lagrangian for gauge groups which are either semisimple or Abelian, or a direct product of groups of both kinds. © 1988.