Time-dependent Photoionization of Gaseous Nebulae: the Pure Hydrogen Case

We study the problem of time-dependent photoionization of low density gaseous nebulae subjected to sudden changes in the intensity of ionizing radiation. To this end, we write a computer code that solves the full time-dependent energy balance, ionization balance, and radiation transfer equations in a self-consistent fashion for a simplified pure hydrogen case. It is shown that changes in the ionizing radiation yield ionization/thermal fronts that propagate through the cloud, but the propagation times and response times to such fronts vary widely and non-linearly from the illuminated face of the cloud to the ionization front (IF). Ionization/thermal fronts are often supersonic, and in slabs initially in pressure equilibrium such fronts yield large pressure imbalances that are likely to produce important dynamical effects in the cloud. Further, we studied the case of periodic variations in the ionizing flux. It is found that the physical conditions of the plasma have complex behaviors that differ from any steady-state solutions. Moreover, even the time average ionization and temperature is different from any steady-state case. This time average is characterized by over-ionization and a broader IF with respect to the steady-state solution for a mean value of the radiation flux. Around the time average of physical conditions there is large dispersion in instantaneous conditions, particularly across the IF, which increases with the period of radiation flux variations. Moreover, the variations in physical conditions are asynchronous along the slab due to the combination of non-linear propagation times for thermal/ionization fronts and equilibration times.Comment: Accepted for publication in ApJ. 36 pages, 12 figure

Maximizing Societal Contributions of Latino Adults by Investing in Latino Children's Health Care

Focuses on the lack of preventive care and health insurance coverage for Latino children, and how this affects their health and school performance and impacts their ability to contribute as adults to California's economy and society

Atomic Processes in Planetary Nebulae and H II Regions

Spectroscopic studies of Planetary Nebulae (PNe) and H {\sc ii} regions have driven much development in atomic physics. In the last few years the combination of a generation of powerful observatories, the development of ever more sophisticated spectral modeling codes, and large efforts on mass production of high quality atomic data have led to important progress in our understanding of the atomic spectra of such astronomical objects. In this paper I review such progress, including evaluations of atomic data by comparisons with nebular spectra, detection of spectral lines from most iron-peak elements and n-capture elements, observations of hyperfine emission lines and analysis of isotopic abundances, fluorescent processes, and new techniques for diagnosing physical conditions based on recombination spectra. The review is directed toward atomic physicists and spectroscopists trying to establish the current status of the atomic data and models and to know the main standing issues.Comment: 9 pages, 1 figur

Dietary DL-alpha-tocopheryl acetate enhances growth, survival, and resistance against an abrupt shift to higher salinity of the Asian catfish (Clarias macrocephalus) fry

The effect of dietary supplementation of DL-alpha-tocopheryl acetate (a-TA) on growth performance, feed efficiency, survival, and salinity resistance of Asian catfish (Clarias macrocephalus) fry was evaluated. A total of 750 catfish fry were divided into five treatments with three replicates and fed experimental diets containing varying levels of alpha-TA: 0, 100, 200, 300, and 400 mg·kg-1 diet for 45 days. Results show that catfish fry-fed diets supplemented with alpha-TA exhibited significantly higher weight gain (WG) and final average body weight (FABW), better specific growth rates (SGR) and feed conversion ratio (FCR), and significantly higher survival rates compared to those of the control group fed the basal diet (P < 0.05). Better salinity resistance was observed in the Asian catfish fed the alpha-TA-supplemented diets when abruptly exposed to higher salinity (10 ppt) for up to 48 h. In addition, the diet attractability test revealed that alpha-TA-supplemented diets attracted significantly more catfish fry than the basal diet lacking vitamin E (P < 0.05). In conclusion, the results demonstrated that dietary supplementation of alpha-TA (vitamin E) improved growth, feed efficiency, feed attractability, survival, and resistance to abrupt higher salinity exposure of Clarias macrocephalus fry

Effects of vitamin E on growth and maturation in the Asian catfish (Clarias macrocephalus) at puberty

The maturation of male fish is a problematic aspect of Clarias macrocephalus and probably one of the causes of the population's disappearance in the usual places where they once abound. The present study aimed to explore feed additives to enhance its maturation from puberty. Vitamin E (VE) is essential in the reproduction of animals, including fish. A growth trial was conducted in which groups of C. macrocephalus were fed experimental diets containing graded levels of VE in the form of α-tocopheryl acetate (α-TA), namely, 0, 100, 200, 300 and 400 mg VE·kg-1 diet. After 90 days, growth and maturation were assessed, and reproductive performance was tested by conducting induced spawning and artificial fertilization. Results showed growth and nutrient utilization indices were better in groups fed diets containing VE than in the control group. Maturation indices such as GSI, gonad weight, lengths, egg diameter, and fecundity were enhanced in the VE-treated groups. Reproductive performance, such as fertilization, hatching, and larval survival rate, was enhanced in C. macrocephalus broodstock in VE-treated groups. Quantitative estimates for optimal VE dose that elicited maximal response values ranged from 202.1 to 230.0 mg VE·kg-1 diet

17α-Methyltestosterone enhances growth and reproductive performance of immature male Asian catfish (Clarias macrocephalus)

This study aimed to assess the effects of 17α-methyltestosterone (MT) on the growth and reproductive performance of male Asian catfish (Clarias macrocephalus). A total of 36 immature male Asian catfish (ABW = 125.97 g) were randomly distributed into 12 circular tanks, and fed with either the control diet (with no MT) or diets containing MT at 60 mg·kg-1, 90 mg·kg-1, or 120 mg·kg-1 for 45 days. Results showed that weight gain (WG), specific growth rate (SGR) and feed intake (FI) were significantly higher in the male catfish fed with diets containing 60 and 90 mg·kg-1 MT than in those fed with the control diet. Also, the diet attractability test revealed that the 60 and 90 mg·kg-1 MT groups significantly attracted more catfish than did the control diet; however, increasing MT to 120 mg·kg-1 reduced its attractability to the immature male catfish. MT-treated male catfish exhibited significantly heavier and significantly longer testes than male catfish fed the control diet at the termination of the feeding trial. These male catfish also exhibited significantly higher gonadosomatic indices (GSI) than catfish in the control group. Following induced spawning of nontreated female catfish and artificial fertilization of its eggs using testis preparation from the experimental male catfish at the termination of the feeding trial, results showed that testis preparations from all MT-treated males resulted in significantly higher fertilization (FR) and hatching rates (HR) of the eggs. In conclusion, incorporating MT to the diet improved both the growth and reproductive performance of the male Clarias macrocephalus. Precisely, dosages of optimal dietary MT using a quadratic model for maximal SGR, GSI, FR, and HR values were estimated to be 58.3, 75.0, 90.6, and 78.2 mg·kg-1, respectively

Benfotiamine in high carbohydrate diet enhances growth and reproductive performance of the Asian native catfish Clarias macrocephalus subadults

Clarias macrocephalus has been extirpated in most regions in the Philippines and as a preliminary study towards its reintroduction, we aimed at enhancing the growth and reproductive performance of the broodstock. Several studies have identified thiamine deficiency as a factor in the extirpation of some important fish species in the wild. The present study aimed to determine the effects of elevated dietary carbohydrates and benfotiamine, a more bioavailable analog of thiamine (vitamin B1). Three diets were used, namely, a commercial diet specific for catfish was used as the control diet (Com), a high carbohydrate (HC) diet, and a benfotiamine-supplemented HC diet (HCB). Results show that survival of the subadult catfish in captivity for 10 weeks was remarkably high, exhibiting an average of 99% for all three treatments (P>0.05). HCB diet resulted in significantly higher final average body weight (FABW), weight gain (WG), specific growth rate (SGR), and significantly best food conversion ratio (FCR) (P0.05). For the reproductive performance, female Asian catfish fed the HCB diet exhibited significantly heavier ovary and liver (P0.05). GSI of the female catfish and fecundity were significantly higher in the HCB group (P0.05). In the male catfish, testes were significantly heavier in the HCB group (P0.05). HSI, male LW, and LL were significantly higher in the HC and HCB groups (P>0.05) than in the Com group (P0.05). In conclusion, elevating dietary carbohydrates in the diet from 7.70% to 22.73% (i.e., Com to HC diet, respectively) did not negatively affect the growth and reproductive performance of the Asian catfish. Further supplementation of benfotiamine at 0.02% to the HC diet enhanced significantly both the growth and reproductive performance of the Asian catfish

N-methyl-N-((1-methyl-5-(3-(1-(2-methylbenzyl)piperidin-4-yl)propoxy)-1H-indol-2-yl)methyl)prop-2-yn-1-amine, a new cholinesterase and monoamine oxidase dual inhibitor

On the basis of N-((5-(3-(1-benzylpiperidin-4-yl)propoxy)-1-methyl-1H-indol-2-yl)methyl)-N-methylprop-2-yn-1-amine (II, ASS234) and QSAR predictions, in this work we have designed, synthesized, and evaluated a number of new indole derivatives from which we have identified N-methyl-N-((1-methyl-5-(3-(1-(2-methylbenzyl)piperidin-4-yl)propoxy)-1H-indol-2-yl)methyl)prop-2-yn-1-amine (2, MBA236) as a new cholinesterase and monoamine oxidase dual inhibitor.PostprintPostprintPeer reviewe