Reproductive Bioenergetics of Wood Ducks

The Auk ◽  
1980 ◽  
Vol 97 (3) ◽  
pp. 480-490 ◽  
Author(s):  
Ronald D. Drobney
Keyword(s):  
Egg Production ◽  
Energy Content ◽  
Temporal Distribution ◽  
High Energy ◽  
High Energy Density ◽  
Aix Sponsa ◽  
Fat Reserves ◽  
Wood Ducks ◽  
Large Numbers ◽  
Wood Duck

Abstract A model for the daily energy requirements during egg production was developed for Wood Duck (Aix sponsa) hens laying a 12-egg clutch. Reproductive requirements are high, because Wood Ducks lay large clutches of relatively large eggs that have a high energy density. Costs totaled 5,996 kJ and included 2,969 kJ for carbohydrates and lipids, 1,595 kJ for protein, and an estimated 1,432 kJ for biosynthesis. Both are the temporal distribution of costs and the use of stored fat reserves are thought to be important factors enabling hens to meet these large requirements. Costs equivalent to that of an entire egg are incurred for only 6 days during the cycle, because costs are distributed over an 18-day period rather than the 12 days of laying. The energy content of body fat expended by hens was sufficient to account for 88% of the estimated requirements for biosynthesis and the nonprotein fraction of the oviduct and clutch. Protein and minerals are primarily dietary requirements and are obtained by foraging for invertebrates during laying. Although an egg contains only about 5 g of protein, hens must consume large numbers of invertebrates to meet this requirement. The ability to meet most nonprotein requirements with stored fat may therefore be essential to ensure that hens have enough time to forage for invertebrates.

scholarly journals All day-long: Sticklebacks effectively forage on whitefish eggs during all light conditions

PLoS ONE ◽  
2021 ◽  
Vol 16 (8) ◽  
pp. e0255497
Author(s):  
Jan Baer ◽  
Sarah Maria Gugele ◽  
Joachim Bretzel ◽  
J. Tyrell DeWeber ◽  
Alexander Brinker
Keyword(s):  
Egg Production ◽  
Gasterosteus Aculeatus ◽  
Energy Content ◽  
Stomach Content Analysis ◽  
Pelagic Zone ◽  
Light Conditions ◽  
Egg Predation ◽  
Large Numbers ◽  
Potential Benefits ◽  
Freshwater Stickleback

The three-spined stickleback Gasterosteus aculeatus invaded Lake Contance in the 1940s and expanded in large numbers from an exclusively shoreline habitat into the pelagic zone in 2012. Stickleback abundance is very high in the pelagic zone in winter near the spawning time of pelagic whitefish Coregonus wartmanni, and it is hypothesized that this is triggered by the opportunity to consume whitefish eggs. Field sampling has qualitatively confirmed predation of whitefish eggs by stickleback, but quantification has proven difficult due to stormy conditions that limit sampling. One fundamental unknown is if freshwater stickleback, known as visual feeders, can successfully find and eat whitefish eggs during twilight and night when whitefish spawn. It is also unknown how long eggs can be identified in stomachs following ingestion, which could limit efforts to quantify egg predation through stomach content analysis. To answer these questions, 144 individuals were given the opportunity to feed on whitefish roe under daylight, twilight, and darkness in controlled conditions. The results showed that stickleback can ingest as many as 100 whitefish eggs under any light conditions, and some individuals even consumed maximum numbers in complete darkness. Furthermore, eggs could be unambiguously identified in the stomach 24 hours after consumption. Whitefish eggs have 28% more energy content than the main diet of sticklebacks (zooplankton) based on bomb-calorimetric measurements, underlining the potential benefits of consuming eggs. Based on experimental results and estimates of stickleback abundance and total egg production, stickleback could potentially consume substantial proportions of the total eggs produced even if relatively few sticklebacks consume eggs. Given the evidence that stickleback can feed on eggs during nighttime spawning and may thereby hamper recruitment, future studies aimed at quantifying actual egg predation and resulting effects on the whitefish population are urgently needed.

Computational insights into novel dicobalt polynitrogen: structure, stability, intermolecular interaction, and application

2017 ◽  
Vol 95 (6) ◽  
pp. 656-663
Author(s):  
Tingting Zhu ◽  
Ping Ning ◽  
Jinhui Peng ◽  
Xiuying Zhang ◽  
Lihong Tang
Keyword(s):  
Energy Density ◽  
Intermolecular Interaction ◽  
Density Functional ◽  
Energy Content ◽  
Energetic Material ◽  
High Energy ◽  
High Energy Density ◽  
Structure Stability ◽  
Chemical Hardness ◽  
Covalent Interaction

Previous studies have suggested that polynitrogen species are significant as potential candidates for superior energetic material. In this paper, the polynitrogen species of Co2(N5)4 were reasonably designed and studied by the density functional theory (DFT), and five isomers of Co2(N5)4 were selected. These species were explored in detail, including structure, stability, intermolecular interaction, and application. The five isomers, each with its own special structure feature, were stable enough based on the analysis of bond energy, chemical hardness, and aromaticity. Furthermore, the intermolecular interactions suggested the presence of a covalent interaction in the Co–Co and N–N bonds, the electronic delocalization in cyclo-N5, and the ionic feature in the Co–N bond. In addition, all of the title species held high-energy content. Compared with the known high energy density materials of HB(N5)3Be2(N5)3BH, energetic material of nitromethane, and famous nitramine explosive HMX (1,3,5,7-tetranitro-1,3,5,7-tetrazocane), Co2(N5)4 holds a stronger advantage. The five Co2(N5)4 species were located at 27.8–35.8 kcal/mol per N2 unit, their energy densities were about 2.73 × 104 MJ/kg, and their mass densities were in the range of 2.60–2.74 g/cm3. Significantly, the 4-1 was the most stable, and its density was also the greatest among the five species. Thus, it has the most potential as a high energy density material.

scholarly journals Conversion of poplar biomass into high-energy density tricyclic sesquiterpene jet fuel blendstocks

2020 ◽  
Vol 19 (1) ◽  
Author(s):  
Gina M. Geiselman ◽  
James Kirby ◽  
Alexander Landera ◽  
Peter Otoupal ◽  
Gabriella Papa ◽  
...  
Keyword(s):  
Energy Density ◽  
Lignocellulosic Biomass ◽  
Energy Content ◽  
Carbon Sources ◽  
High Energy ◽  
Jet Fuel ◽  
Fuel Properties ◽  
Aviation Fuel ◽  
High Energy Density ◽  
Jet Fuels

Abstract Background In an effort to ensure future energy security, reduce greenhouse gas emissions and create domestic jobs, the US has invested in technologies to develop sustainable biofuels and bioproducts from renewable carbon sources such as lignocellulosic biomass. Bio-derived jet fuel is of particular interest as aviation is less amenable to electrification compared to other modes of transportation and synthetic biology provides the ability to tailor fuel properties to enhance performance. Specific energy and energy density are important properties in determining the attractiveness of potential bio-derived jet fuels. For example, increased energy content can give the industry options such as longer range, higher load or reduced takeoff weight. Energy-dense sesquiterpenes have been identified as potential next-generation jet fuels that can be renewably produced from lignocellulosic biomass. Results We developed a biomass deconstruction and conversion process that enabled the production of two tricyclic sesquiterpenes, epi-isozizaene and prespatane, from the woody biomass poplar using the versatile basidiomycete Rhodosporidium toruloides. We demonstrated terpene production at both bench and bioreactor scales, with prespatane titers reaching 1173.6 mg/L when grown in poplar hydrolysate in a 2 L bioreactor. Additionally, we examined the theoretical fuel properties of prespatane and epi-isozizaene in their hydrogenated states as blending options for jet fuel, and compared them to aviation fuel, Jet A. Conclusion Our findings indicate that prespatane and epi-isozizaene in their hydrogenated states would be attractive blending options in Jet A or other lower density renewable jet fuels as they would improve viscosity and increase their energy density. Saturated epi-isozizaene and saturated prespatane have energy densities that are 16.6 and 18.8% higher than Jet A, respectively. These results highlight the potential of R. toruloides as a production host for the sustainable and scalable production of bio-derived jet fuel blends, and this is the first report of prespatane as an alternative jet fuel.

The effects of dietary energy content on the response of dairy cows to body condition at calving

1989 ◽  
Vol 49 (2) ◽  
pp. 183-191 ◽  
Author(s):  
G. P. Jones ◽  
P. C. Garnsworthy
Keyword(s):  
Milk Yield ◽  
Energy Content ◽  
High Energy ◽  
Milk Composition ◽  
Metabolizable Energy ◽  
Energy Concentration ◽  
Dietary Energy ◽  
Fat Reserves ◽  
Condition Score ◽  
Beet Pulp

ABSTRACTFour groups of six cows were fed from 12 weeks before calving to achieve condition scores at calving of 3·23 (F) and 1·98 (T). For the first 20 weeks of lactation all cows were given 10 kg/day of isonitrogenous (180 g crude protein per kg dry matter (DM)) compounds containing either a high (13·0 MJ/kg DM; HE) or a low (9·8 MJ/kg DM; LE) concentration of metabolizable energy, together with 3 kg/day molassed sugar-beet pulp and hay offered ad libitum.The mean milk yield of cows receiving compound HE (27·7 kg/day) was higher (P > 0·05) than that of cows receiving compound LE (25·6 kg/day). Cows in group FHE yielded 27·0 kg/day, compared with 25·5 kg/day for FLE (P > 0·05); cows in group THE yielded 28·4 kg/day compared with 25·17 kg/day for TLE (P <0·05). After peak lactation, milk yields were maintained better in group THE but declined at a faster rate in group TLE than in groups FHE and FLE. Neither dietary energy concentration nor condition score at calving significantly affected milk composition (butterfat 43·5, protein 29·1, lactose 50·2 g/kg). Cows receiving compound HE consumed significantly (P < 0·001) more energy (208 MJ/day) than cows receiving compound LE (188 MJ/day). Over the first 10 weeks of lactation, changes in condition were –0·83, –0·88 +0·08 and –0·25 (s.e.d. 0·22, P < 0·05) condition score units for cows in groups FHE, FLE, THE and TLE respectively.It is concluded that with diets of high energy concentration intake is mainly limited by physiological mechanisms so that thin cows eat more than fat cows and produce similar amounts of milk. With diets of lower energy concentration, intake is limited by rumen capacity and thin cows eat the same as fat cows. This results in increased fat mobilization and a slight decrease in milk yield by cows which are fat at calving but the limited fat reserves of cows which are thin at calving are insufficient to compensate for reduced energy intake so large reductions in milk yield are observed.

scholarly journals Nest parasitism, promiscuity, and relatedness among wood ducks

PLoS ONE ◽  
2021 ◽  
Vol 16 (12) ◽  
pp. e0257105
Author(s):  
Kayla Harvey ◽  
Philip Lavretsky ◽  
Justyn Foth ◽  
Christopher K. Williams
Keyword(s):  
Extreme Case ◽  
Mitochondrial Control Region ◽  
Aix Sponsa ◽  
Nest Parasitism ◽  
Wood Ducks ◽  
Cavity Nesting ◽  
Nuclear Loci ◽  
Relationship Of ◽  
Wood Duck ◽  
Do So

Nest parasitism is a common reproductive strategy used by many species of cavity nesting birds. Among these, the wood duck (Aix sponsa) is known to have evolved very specific strategies of when and whom to parasitize that is often based on population and/or environmental queues. Here, we investigated the genetic relationship of two female wood ducks competing over an artificial nesting box in Delaware, including the continued incubation of one female despite the death and body remains of the other female throughout the incubation process. We test whether such an extreme case of nest parasitism can be explained by relatedness, egg lineage composition, or a combination of other factors. To do so, we extracted genomic DNA from blood and tissue of the females, as well as chorioallantoic membranes of all viable and inviable eggs. Subsequently, we assessed relatedness among females and eggs based on hundreds of nuclear loci and the mitochondrial control region. We concluded that (1) the two incubating females were entirely unrelated, (2) the single clutch is in fact represented by a minimum of four unrelated females, and (3) a single female can lay eggs sired by different males. The latter finding is the first direct evidence for successful extra-pair copulation in wood ducks. With decreasing costs and increasing effectiveness, genomic methods have the potential to provide important insights into more complex ecological and evolutionary tactics of such populations.

Effect of Diet on Visceral Morphology of Breeding Wood Ducks

The Auk ◽  
1984 ◽  
Vol 101 (1) ◽  
pp. 93-98 ◽  
Author(s):  
Ronald D. Drobney
Keyword(s):  
Food Intake ◽  
Dietary Fiber ◽  
Diet Quality ◽  
Fiber Content ◽  
Aix Sponsa ◽  
Digestive Organs ◽  
Wood Ducks ◽  
Mean Size ◽  
The Mean ◽  
Wood Duck

Abstract Changes in Wood Duck (Aix sponsa) digestive organs reflect adaptations to accommodate changes in diet quality, metabolism, and food intake. The size of the gizzard, intestine, ceca, and liver of males decreased between fall and spring and correlated with a reduction in the fiber content of the diet. The mean size of the intestine, liver, and ceca of hens increased in response to high dietary fiber in fall and hyperphagia during laying. Decreases in the size of digestive organs in hens were associated with reduced feeding during incubation and decreased dietary fiber between fall courtship and prebreeding.

scholarly journals Generation of H2 on Board Lng Vessels for Consumption in the Propulsion System

2020 ◽  
Vol 27 (1) ◽  
pp. 83-95
Author(s):  
Ignacio Arias Fernández ◽  
Manuel Romero Gómez ◽  
Javier Romero Gómez ◽  
Luis M. López-González
Keyword(s):  
Energy Density ◽  
Energy Efficient ◽  
Storage Systems ◽  
Energy Content ◽  
Storage System ◽  
High Energy ◽  
High Energy Density ◽  
Injection System ◽  
Gas Combustion ◽  
Safety Hazard

AbstractAt present, LNG vessels without reliquefaction plants consume the BOG (boil-off gas) in their engines and the excess is burned in the gas combustion unit without recovering any of its energy content. Excess BOG energy could be captured to produce H2, a fuel with high energy density and zero emissions, through the installation of a reforming plant. Such H2 production would, in turn, require on-board storage for its subsequent consumption in the propulsion plant when navigating in areas with stringent anti-pollution regulations, thus reducing CO2 and SOX emissions. This paper presents a review of the different H2 storage systems and the methods of burning it in propulsion engines, to demonstrate the energetic viability thereof on board LNG vessels. Following the analysis, it is identified that a pressurised and cooled H2 storage system is the best suited to an LNG vessel due to its simplicity and the fact that it does not pose a safety hazard. There are a number of methods for consuming the H2 generated in the DF engines that comprise the propulsion plant, but the use of a mixture of 70% CH4-30% H2 is the most suitable as it does not require any modifications to the injection system. Installation of an on-board reforming plant and H2 storage system generates sufficient H2 to allow for almost 3 days’ autonomy with a mixture of 70%CH4-30%H2. This reduces the engine consumption of CH4 by 11.38%, thus demonstrating that the system is not only energy-efficient, but lends greater versatility to the vessel.

scholarly journals The Nanoscale Frontier

2016 ◽  
Vol 138 (11) ◽  
pp. 45-47
Author(s):  
Jeffrey Winters
Keyword(s):  
Carbon Nanotubes ◽  
Energy Density ◽  
Pipe Wall ◽  
High Energy ◽  
Convective Transport ◽  
High Energy Density ◽  
Water Molecules ◽  
Nanoscale Structures ◽  
Large Numbers ◽  
Channel Surface

This article presents an overview of various aspects of nanoscale technology. As opposed to the macroscale, where water molecules next to a pipe wall have zero velocity, in nanochannels, fluid molecules slip at the channel surface, experiencing an enhanced convective transport. Nanotechnology can also help us alter natural designs. Carbon nanotubes act like a reinforcement to give synthetic tissue the strength, stiffness, and viscoelastic performance of natural membranes. In order to store macroscopically significant amounts of energy, one needs to deform large numbers of carbon nanotubes. It is more challenging still to deform them in a way that maintains high-energy density of overall system. Micro- and nanoscale structures have given us capabilities to interact with cells and pathogens at their level as never before and helped us understand how they live, grow, multiply, differentiate, and die.

scholarly journals HUBUNGAN DENSITAS ENERGI DAN ASUPAN CAIRAN DENGAN BERAT JENIS URIN PADA REMAJA

2017 ◽  
Vol 6 (4) ◽  
pp. 326
Author(s):  
Liani Setyarsih ◽  
Martha Ardiaria ◽  
Deny Yudi Fitranti
Keyword(s):  
Physical Activity ◽  
Energy Density ◽  
Specific Gravity ◽  
Fluid Intake ◽  
Energy Content ◽  
High Energy ◽  
High Energy Density ◽  
Observational Research ◽  
Urine Specific Gravity ◽  
Hydration Status

Background: Hydration status is a condition that describes total body fluid. One of the method of measuring hydration status is urine specific gravity. Energy density of food is the amount energy content of total weight food. Foods with high energy density tend to have a lower water content, which will affect fluid intake. The aim of this research was to know the correlation of energy density and fluid intake with urine specific gravity as one of the markers of hydration status. Method: This was an observational research with cross-sectional study design. The research was conducted in Senior High School 15 Semarang involving 55 subjects by Simple Random Sampling method. Food intake and fluid intake were assessed by 1x24 hours Food Recall. Urine specific gravity measured in laboratory. Body fat percentage measured by BIA (Bioelectrical Impendance Analysis) and physical activity assessed by 1x24 hours record physical activity. Data were analyzed by rank spearman.Result: Median of urine specific gravity men and women was 1,02 g/ml. Mean of energy density in men was 1,8±0,32 kcal/gram, in women was 2,1±0,59 kkal/gram. Mean of fluid intake in men was 2406,4±491,38 ml, in women was 2159,5±648,42ml. There was significant correlation of fluid intake with hydration status (p=0,027). There was no significant correlation of energy density and hydration status (p=0,218). Multivariate analysis showed that 14,6% of hydration status is affected by both fluid intake and energy intake. Conclusion: There was significant correlation of fluid intake with urine specific gravity. There was no significant correlation of energy density and urine specific gravity.

Energetic Fuels for Combustion Applications

1996 ◽  
Vol 118 (3) ◽  
pp. 180-186 ◽  
Author(s):  
C. Segal ◽  
W. Shyy
Keyword(s):  
Energy Content ◽  
Theoretical Models ◽  
High Energy ◽  
Molecular Structures ◽  
Hydrocarbon Fuels ◽  
High Energy Density ◽  
Future Research ◽  
Molecular Conformations ◽  
Exothermic Reactions ◽  
Combustion Processes

New fuels with high-energy-density are desirable for many combustion applications. Two types are reviewed in this paper, namely, mixtures resulting from addition of certain metallic or nonmetallic elements to conventional hydrocarbon fuels, and newly synthesized hydrocarbon fuels with strained molecular conformations or more densely packed molecular structures. Despite the favorable effects of high-energy content, these materials often exhibit low reactivity and their ability to improve the performance of practical combustion systems relies strongly on their interaction with the dynamics of the surrounding fluid flow. The intensity of the combustion processes of these materials is dictated, in general, by the melting, evaporation, pyrolysis, mixing, and exothermic reactions processes. Unlike other conventional hydrocarbon fuels, all these processes time scales are often comparable with each other, causing difficulties to devise simpler theoretical models to predict the combustion characteristics. Both the advances made in recent years and the needs for future research and development in the field of energetic fuels are discussed.

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