IMPACT OF INDUSTRY IN RURAL ECONOMIES: AN INPUT-OUTPUT APPROACH

Community/Rural/Urban Development,

Evolution and diversification of a sexually dimorphic luminescent system in ponyfishes (Teleostei: Leiognathidae), including diagnoses for two new genera

A phylogeny was generated for Leiognathidae, an assemblage of bioluminescent, Indo-Pacific schooling fishes, using 6175 characters derived from seven mitochondrial genes ( 16S , COI , ND4 , ND5 , tRNA-His , tRNA-Ser , tRNA-Leu ), two nuclear genes ( 28S , histone H3 ), and 15 morphological transformations corresponding to features of the fishes' sexually dimorphic light-organ system (LOS; e.g., circumesophageal light organ, lateral lining of the gas bladder, transparent flank and opercular patches). Leiognathidae comprises three genera, Gazza , Leiognathus , and Secutor . Our results demonstrate that Leiognathidae, Gazza , and Secutor are monophyletic, whereas Leiognathus is not. The recovered pattern of relationships reveals that a structurally complex, strongly sexually dimorphic and highly variable species-specific light organ is derived from a comparatively simple non-dimorphic structure, and that evolution of other sexually dimorphic internal and external features of the male LOS are closely linked with these light-organ modifications. Our results demonstrate the utility of LOS features, both for recovering phylogeny and resolving taxonomic issues in a clade whose members otherwise exhibit little morphological variation. We diagnose two new leiognathid genera, Photopectoralis and Photoplagios , on the basis of these apomorphic LOS features and also present derived features of the LOS to diagnose several additional leiognathid clades, including Gazza and Secutor . Furthermore, we show that five distinct and highly specialized morphologies for male-specific lateral luminescence signaling, which exhibit species-specific variation in structure, have evolved in these otherwise outwardly conservative fishes. Leiognathids inhabit turbid coastal waters with poor visibility and are often captured in mixed assemblages of several species. We hypothesize that the species-specific, sexually dimorphic internal and external modifications of the leiognathid LOS provide compelling evidence for an assortative mating scheme in which males use species-specific patterns of lateral luminescence signaling to attract mates, and that this system functions to maintain reproductive isolation in these turbid coastal environments. © The Willi Hennig Society 2005.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/72092/1/j.1096-0031.2005.00067.x.pd

Morphology and evolution of the luminous roughy bioluminescent organ (Teleostei: Trachichthyidae)

INTRODUCTION Bioluminescent organs in fishes that produce ventral camouflage against a background of downwelling light are very common, yet their anatomy often is poorly understood (Hastings, 1971; Young & Roper, 1976). Camouflage via ventral bioluminescence has evolved at least seven times within a wide range of teleosts (Haddock et al., 2010; Davis et al., 2014, 2016) and they vary greatly in the anatomical structures that form them (Haygood et al., 1994; Chakrabarty et al., 2011; Ghedotti et al., 2015, 2018). The luminous roughies (genus Aulotrachichthys) have a light organ in the region of the anus that houses lumiescent bacteria in the genus Photobacterium. Kuwabara (1955) and Haneda (1957) discuss the anatomy and function of the bioluminescent organ in A. prosthemius noting that it contained Photobacterium in lobules in an area around the anus (Fig. 1) and a light conducting structure they called the “unknown” structure or the filiform body respectively. We seek to determine more specifically the structure of the bioluminescent organ in A. prosthemius and determine if Paratrachichthys, a closely related genus, is similarly bioluminescent. We also generate a phylogeny to better understand the evolution of bioluminescence in the Family Trachichthyidae

Spiking Neurons Learning Phase Delays

Time differences between the two ears are an important cue for animals to azimuthally locate a sound source. The first binaural brainstem nucleus, in mammals the medial superior olive, is generally believed to perform the necessary computations. Its cells are sensitive to variations of interaural time differences of about 10 μs. The classical explanation of such a neuronal time-difference tuning is based on the physical concept of delay lines. Recent data, however, are inconsistent with a temporal delay and rather favor a phase delay. By means of a biophysical model we show how spike-timing-dependent synaptic learning explains precise interplay of excitation and inhibition and, hence, accounts for a physical realization of a phase delay

Spectroscopy of formaldehyde in the 30140-30790cm^-1 range

Room-temperature absorption spectroscopy of formaldehyde has been performed in the 30140-30790cm^-1 range. Using tunable ultraviolet continuous-wave laser light, individual rotational lines are well resolved in the Doppler-broadened spectrum. Making use of genetic algorithms, the main features of the spectrum are reproduced. Spectral data is made available as Supporting Information

Differential cross sections for pion charge exchange on the proton at 27.5 MeV

We have measured pion single charge exchange differential cross sections on the proton at 27.5 MeV incident $\pi^-$ kinetic energy in the center of momentum angular range between $0^\circ$ and $55^\circ$. The extracted cross sections are compared with predictions of the standard pion-nucleon partial wave analysis and found to be in excellent agreement.Comment: ReVTeX v3.0 with aps.sty, 23 pages in e-print format, 7 PostScript Figures and 4 Tables, also available via anonymous ftp at ftp://helena.phys.virginia.edu/pub/preprints/scx.p

Photoassociation spectroscopy of cold calcium atoms

Photoassociation spectroscopy experiments on 40Ca atoms close to the dissociation limit 4s4s 1S0 - 4s4p 1P1 are presented. The vibronic spectrum was measured for detunings of the photoassociation laser ranging from 0.6 GHz to 68 GHz with respect to the atomic resonance. In contrast to previous measurements the rotational splitting of the vibrational lines was fully resolved. Full quantum mechanical numerical simulations of the photoassociation spectrum were performed which allowed us to put constraints on the possible range of the calcium scattering length to between 50 a_0 and 300 a_0

Murfreesboro Addresses

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