Transverse mode control and switching in gas laser arrays

Theoretical and experimental investigations of multiple transverse mode laser oscillation involving spatially varying gain and loss are carried out. The effect of gain and loss distribution on mode competition is analyzed. Numerical examples are given for a CO2 waveguide laser array. Experimental results of CO2 laser arrays are found to be consistent with the theory, and robust in-phase coupled mode array operation has been achieved

Intramolecular dynamics. II. Artificial intelligence search evaluation function and treatment of resonance centers for large systems

The role of resonance centers in obtaining large size matrices via an artificial intelligence (AI) search is discussed. The results are used to develop for an AI search an evaluation function which takes cognizance of isolated internal resonances in these many-state systems. The effect of later-accepted states on resonance centers is included. This evaluation function and one without a resonance factor are used in Part III of this series. A search is made there to select zeroth-order vibrational states of benzene that are used in a diagonalization treatment of CH overtone spectra. When there are many overlapping resonances, as in that case, a comparison of results obtained with those two types of evaluation function is of particular interest

Influences of Random Surface Waves on the Estimates of Wind Energy Input to the Ekman Layer in the Antarctic Circumpolar Current Region

Sea surface waves significantly affect the wind energy input to the Ekman layer in the upper ocean. In the study, we first incorporated the wave-induced Coriolis-Stokes forcing, the reduction of wind stress caused by wave generation, and wave dissipation into the classical Ekman model to investigate the kinetic energy balance in the wave-affected Ekman layer. Then, both the theoretical steady state solution for the idealized condition and the nonsteady state solution for the realistic ocean were derived. Total energy input to the wave-affected Ekman layer includes the wind stress energy input and the wave-induced energy input. Based on the WAVEWATCH III model, the wave spectrum was simulated to represent realistic random directional wave conditions. The wind stress energy input and the wave-induced energy input to the wave-affected Ekman layer in the Antarctic Circumpolar Current in the period from 1988 to 2010 were then calculated. The annual mean total energy input in the Antarctic Circumpolar Current region was 402.5 GW and the proportions of the wind stress energy input and the wave-induced energy input were, respectively, 85% and 15%. Particularly, total energy input in the Antarctic Circumpolar Current in the wave-affected Ekman layer model was 59.8% lower than that in the classical Ekman model. We conclude that surface waves play a significant role in the wind energy input to the Ekman layer

The Effect of Dietary Protein Level on the Growth Performance and Digestive Protease Activity in Juvenile Bluegill (Lepomis macrochrius)

A 16-week feeding experiment was conducting in an indoor recirculating aquaculture system (RAS) to determine the effects of dietary protein level on the growth and digestive protease activity in juvenile bluegills. Six isocaloric experimental diets were forumalted with 32%, 35%, 38%, 41%, 44%, and 47% levels of protein. Menhdaen fish meal was use as the sole protein source. Juvenile bluegills of 24.91 ± 0.50 g initial weight were distributed into 24 151 L tanks with 12 fish each. Each diet had four replications. Fish were fed to satiation three times a day by hand. At the termination, there no mortalities in fish fed 38% through 47% protein diet. Bluegill fed 38% or 47% protein diet had significant higher body weight gain and specific growth rate (SGR) than fish fed 32% or 35% [rotein diet. No significant differences (p\u3e0.05) were found in weight gain, SGR, and FCR among the fish fed 38% or higher protein diets. Protein efficiency ratio decreased with increasing dietary protein level from 32% to 47%. Acid protease activity of complete digestive tract increased in trend with increasing dietary protein level from 32% to 47%. No significant differences were detected in the protease activity at different pH level among the treatments. The optimal dietary protein requirement for juvenile bluegill was about 38.3%.https://bluetigercommons.lincolnu.edu/lucer-pubs/1001/thumbnail.jp

The Effects of Dietary Protein-to-Energy Ratio on Juvenile Bluegill (Lepomis macrochirus) Growth with Observations of Sexual Dimorphism

Bluegill is a promising aquaculture species in the Midwest. males are typically larger than females. However, there is little or no information on nutritional differences between sexes and protein-to-energy ratio. The objective of this study was to characterize the protein-to-energy ratio in juvenile bluegill with observations on gender differences. Bluegill (20-30g) were fed diets consisting of 35% protein with 14, 16, and 18% lipids and 38% protein with 12, 14, and 16% lipids. Four replicates of 12 fish each were fed the diets for 16 weeks. Terminal mean body weights, lengths, liver wights, visceral weights, hepatic somatics indices (HSI), and visceral somatic indices (VSI) were recorded. No differences were found in the mean body weights, lengths, or visceral weights among diets. Increased liver weights, HSI, and VSI were observed in treated with 35% protein. The study revealed sexual dimporphism in body weights, lengths, HSI, VSI, and visceral weights. When data were compared by sexes there were more differences and patterns than among diets compared by the overall means. No differences in the body weights and lengths were found among fish fed different diets. Liver characteristics of fish fed the 35% diets could indicate future fish growth problems. There is a need for further investigation of the effect of gender on feeding trials.https://bluetigercommons.lincolnu.edu/lucer-pubs/1005/thumbnail.jp

Amino Acid Profiles in the Tissues of Juvenile Bluegill (Lepomis Macrochirus) from the Wild and Commercially-fed Fish

Amino acid profiles of fish tissues and fish eggs have been extensively investigated in some fish species. Amino acid profiles are helpful in quantifying the indispensable amino acid requirements for these fish. Bluegill is a major forage fish for the largemouth bass (Micropterus samoides) and an important recreational fish throughout the US. The demand for bleugill as a food fish has increased recently. However, the information on the amino acid profiles of its eggs and tissues is lacking. The objectve of this study was to determine the amino acid profiles of the muscles and whole body of the 1-2 g wild and the commercially fed bluegill. Wild fish were obtained from the ponds that relied on the natural food source. Commercially fed fish were grown indoors. Skinless muscles were obtained by dissected both sides of the 1-2 g bluegill. The results showed the lysine was the most abundant indispensable amino acids in muscles and hwole body of both the wild and the farm-raised fish. The proportion of an individual indispensable amino acid to the sum of all detectable amino acids amount was similar for whole body and muscles in wild or raised fish. For whole body or muscle tissue, wild fish contained significantly higher crude protein but lower crude lipid levels than farm-raised bluegill (p\u3c0.05). This study suggested that nutritional history affected tissue proximate compositions.https://bluetigercommons.lincolnu.edu/lucer-pubs/1003/thumbnail.jp

The Distribution of α-Amylase Activity along the Digestive Tract of Juvenile Bluegill (Lepomis macrochirus) and its Comparison with Selected Fish Species

Carbohydrates are the least expensive form of dietary energy for animals. Although fish don\u27t have specific requirements for dietary carbohydrates, they must be provided with the appropriate levels of carbohydrates in their diets. Moderate levels of carbohydrate could support fishs\u27 better growth performance and may decrease the use of the more expensive protein and lipids in the diet. Different fish have different ability to utilize digestible carbohydrates, which may relate to the relative amount of amylase activity present in the digestive system of the various species. α-amylase is a key enzyme for carbohydrate digestion. Bluegill, an important forage and recreational as well as a newly emerged food fish, is the most commonly produced sunfish in the North Central Region. Information on the digestive amylase activity and the dietary carbohydrates utilization in Bluegill is lacking. The objective of this study was to determine the distribution of α-amylase activity along the digestive tract of juvenile Bluegill and to compare its activity with slecte fish species. The α-amylase analysis followed Worthington (1993) with a slight modification. α-amylase was detected in the stomach, pyloric cecum, proximal intestine, mid intestine, and distal intestine in Bluegill. The lowest α-amylase activity was found in the stomach. No difference in α-amylase among the three parts of intestine was detected. α-amylase activity in Bluegill along the digestive tract is higher than that in Black Crappie, but significantly lower than that in Grass Carp (p \u3c 0.05). Knowledge of α amylase may provide useful information for estimating the carbohydrates level for juvenile Bluegill diets.https://bluetigercommons.lincolnu.edu/lucer-pubs/1004/thumbnail.jp

Biweekly Growth Characteristics of Juvenile Bluegill Fed Different Protein Diets

This study evaluated growth rates of juvenile bluegill (Lepomis macrochius) fed different protein levels, raised indoors. Six experimental diets containing protein levels of 32, 35, 38, 41, 44, and 47% with 346 kcal/g energy were fed to four replicates of 12 fish with initial mean weight of 24.9±0.51g. Fish were fed by hand to satiation three times daily for 16 weeks. Percent weight gain, for fish fed 32, 35, 38, 41, 44, and 47% protein diets were 180.5±43.8, 203.6±32.33, 256.4±19.4, 235.8±20.63, 249.1±19.59, and 275.2±47.3, and specific growth rates 0.91±0.15, 0.98±0.10, 1.13±0.05, 1.08±0.05, 1.11±0.05, and 1.17±0.11, respectively for the study. Biweekly mean weight differences (p ≤ 0.05) occured after week eight, with fish fed 47% diet consistently havingh higher mean wight than those fed 32%. Biweekly weight gain was connsistently different after week two between fish fed 47% and 32% protein. However, fish fed 38 and 44% diets sometimes had significantly more gain than those fed 32 and 35%. Biweekly feed consumption differed after week ten with fish fed 47 and 38% consistently consumed more food than fish fed 32% protein. Feed conversion ratio differences occurred at every period with the most common differences seen between the 32 and 47% groups. This study indicated that growth characteristics could be improved with higher protein diets in juvenile bluegill.https://bluetigercommons.lincolnu.edu/lucer-pubs/1006/thumbnail.jp

A mixed-methods national study investigating key challenges in learning English as a foreign language: A Chinese college student perspective

IntroductionThis mixed-methods national study has a two-fold purpose: (a) to invite Chinese college students to rate their overall difficulties in the eight areas of English learning, i.e., listening, speaking, reading, writing, pronunciation, grammar, vocabulary, and culture; and (b) to invite them to identify their key challenges in learning EFL. Specifically, the following three research questions were asked: (a) what are their overall difficulties in the eight areas of learning EFL? (b) Are there significant differences in rating their overall difficulties in these eight areas across the demographic variables of gender (i.e., male versus female participants) and subject discipline (arts versus sciences versus English subject disciplines participants)? And (c) what are their key challenges in learning EFL?MethodsThe participants included a sample of 1,525 freshmen and sophomore students currently studying at seven universities across China. The instrument was a survey that consisted of a five-point Likert scale self-evaluation form and a major essay question addressing their key challenges. The qualitative data can help to probe deeply into the research setting to obtain in-depth understandings about Chinese college students’ English learning; and therefore, they can greatly enhance the quantitative data.Results and discussionThe quantitative results indicated that listening, speaking, and writing were their three key difficult areas in EFL learning; further, students’ subject discipline (arts versus sciences verse English subject disciplines) had significant effects on their perceived learning challenges in English listening and vocabulary. The qualitative results confirmed that listening, speaking, and writing were their three key challenging areas. Their specific learning challenges in each area were examined. Implications for Chinese college English teachers and administrators are discussed in terms of pedagogy and policy making, respectively

Investigation of epidemiological and clinical characteristics of people infected with SARS-CoV-2 during the second pandemic of COVID-19 in Chengdu, China

ObjectiveThis study investigated the epidemiological and clinical characteristics of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) infected patients during the second pandemic of COVID-19 (coronavirus disease of 2019) in Chengdu, China. Furthermore, the differences between first infection and re-infection cases were also compared and analyzed to provide evidence for better prevention and control of SARS-CoV-2 re-infection.MethodsAn anonymous questionnaire survey was conducted using an online platform (wjx.cn) between May 20, 2023 to September 12, 2023.ResultsThis investigation included 62.94% females and 32.97% of them were 18–30 years old. Furthermore, 7.19–17.18% of the participants either did not receive vaccination at all or only received full vaccination, respectively. Moreover, 577 (57.64%) participants were exposed to cluster infection. The clinical manifestations of these patients were mainly mild to moderate; 78.18% of participants had a fever for 1–3 days, while 37.84% indicated a full course of disease for 4–6 days. In addition, 40.66% of the participants had re-infection and 72.97% indicated their first infection approximately five months before. The clinical symptoms of the first SARS-CoV-2 infection were moderate to severe, while re-infection indicated mild to moderate symptoms (the severity of symptoms other than diarrhea and conjunctival congestion had statistically significant differences) (p < 0.05). Moreover, 70.53 and 59.21% of first and re-infection cases had fever durations of 3–5 and 0–2 days, respectively. Whereas 47.91 and 46.40% of first and re-infection cases had a disease course of 7–9 and 4–6 days.ConclusionThe SARS-CoV-2 infected individuals in Chengdu, China, during the second pandemic of COVID-19 had mild clinical symptoms and a short course of disease. Furthermore, compared with the first infection, re-infection cases had mild symptoms, low incidences of complications, short fever duration, and course of disease