Novel Results on the Formation of Volatile Organic Compounds (VOC) in Silages

The incidence of volatile organic compounds, including ethyl esters of lactic and acetic acids, in grass silages was evaluated based on a total of 620 samples from 10 different lab-scale ensiling experiments. These substances were detected after cold-water extraction by gas-chromatography. The correlations between ethanol and esters concentrations varied greatly depending on the trial. It was shown that ethanol concentration and pH of the silages affected ester formation. Low silage pH stimulated ester accumulation. Up to pH of 4.3, a stronger relationship between ethanol and esters contents was found than in grass silages having higher pH values. By allocating the silages to different ethanol classes it was shown that at up to 10 g/kg DM, the correlation between pH and total ester content was very weak (rS = -0.22). At \u3e 10 g ethanol per kg DM, there was a strong negative relationship between the two tested parameters (rS = -0.82). Based on all available data (n = 1148) from different types of silages, a generally valid model is proposed to predict total ester concentrations (y) as a function of ethanol content (x): y = 114x (R2 = 0.76). It is recommended to use silage additives with proven record of reducing ethanol in silages, thereby minimizing the production of ethyl esters and excluding the potential negative effects of volatiles on feed intake

The face of the German house : modernization and cultural anxiety in twentieth-century architectural photographs

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Architecture, 2008.Includes bibliographical references (p. 227-261).This dissertation proposes that architectural photography-which became an independent genre in twentieth century Germany-was a primary route along which the cultural and political conflicts of modernization were addressed within the contested space of public discussion, and that these photographs helped produce the political and cultural changes driving major developments in German architecture and urbanism since the 1920s. My study explores the history of the representational and disciplinary ambiguity between the house photograph and the portrait, with particular attention to political and social connotations in the work of four German practitioners whose photographic oeuvres are more closely related than is commonly understood: Paul Schultze-Naumburg (1896-1949), Albert Renger-Patzsch (1897-1966), August Sander (1876-1964), and Bernd Becher (1931-2007).My study of these figures' architectural photographs highlights their participation in broader debates on architecture and public space, specifically through the overarching metaphor of the "face" of the German building. I argue that the work of these photographers, as well as their circumstances of production, epitomize the concurrent and colliding forces of modernity and industrialization.(cont.) The understanding of the historical precedents and construction of the genre of German architectural photographs demonstrates the contentious issues surfacing in these four figures' work: Paul Schultze-Naumburg's obsession with facial and racial characteristics in portrait as well as architecture photography, Albert Renger-Patzsch's modernist attempt to purge these unsavory ideas by professionalizing architecture photography into an "objective" practice, the analogies to caricature and taxonomy seen in the ubiquitous systems of identification by August Sander, and, finally, the practice of Bernd Becher whose use of the rhetoric of standardization in his photographs of houses appears as a postmodern acknowledgment of the hegemonic achievement of modernization-of both Germany and architectural photography. Spanning the 20th century, the work of these four figures is anchored in a deep anxiety regarding the pace and culture of modernization in Germany; this dissertation challenges the boundaries set up between their respective bodies of work and charts a new history of architectural photography in Germany as a driving force of the volatile history of modernity.by Kirsten Weiss.Ph.D

Spatial two-particle NOON-states in periodically shaken three-well potentials

Few-particle dynamics in a three-well potential are investigated numerically. It is shown that periodically shaking the potential can considerably increase the fidelity of emerging spatial quantum superpositions. Such NOON-states are important for quantum interferometry. If the two particles initially sit in the middle well, the probability to return to this state can distinguish pure quantum dynamics from statistical mixtures. The numeric implementation of decoherence via particle losses shows clear differences from the pure quantum behaviour. A three-well lattice could be an ideal system for experimental realizations

A Search for H2O in the Strongly Lensed QSO MG 0751+2716 at z=3.2

We present a search for 183 GHz H_2O(3_13-2_20) emission in the infrared-luminous quasar MG 0751+2716 with the NRAO Very Large Array (VLA). At z=3.200+/-0.001, this water emission feature is redshifted to 43.6 GHz. As opposed to the faint rotational transitions of HCN (the standard high-density tracer at high-z), H_2O(3_13-2_20) is observed with high maser amplification factors in Galactic star-forming regions. It therefore holds the potential to trace high-density star-forming regions in the distant universe. If indeed all star-forming regions in massively star-forming galaxies at z>3 have similar physical properties as e.g. the Orion or W49N molecular cloud cores, the flux ratio between the maser-amplified H_2O(3_13-2_20) and the thermally excited CO(1-0) transitions may be as high as factor of 20 (but has to be corrected by their relative filling factor). MG 0751+2716 is a strong CO(4-3) emitter, and therefore one of the most suitable targets to search for H_2O(3_13-2_20) at cosmological redshifts. Our search resulted in an upper limit in line luminosity of L'(H_2O) < 0.6 x 10^9 K km/s pc^2. Assuming a brightness temperature of T_b(H_2O) ~= 500 K for the maser emission and CO properties from the literature, this translates to a H_2O(3_13-2_20)/CO(4-3) area filling factor of less than 1%. However, this limit is not valid if the H_2O(3_13-2_20) maser emission is quenched, i.e. if the line is only thermally excited. We conclude that, if our results were to hold for other high-z sources, H_2O does not appear to be a more luminous alternative to HCN to detect high-density gas in star-forming environments at high redshift.Comment: 6 pages, 1 figure, to appear in ApJ (accepted May 19, 2006

An observational study of associations among maternal fluids during parturition, neonatal output, and breastfed newborn weight loss

<p>Abstract</p> <p>Background</p> <p>Newborn weight measurements are used as a key indicator of breastfeeding adequacy. The purpose of this study was to explore non-feeding factors that might be related to newborn weight loss. The relationship between the intravenous fluids women receive during parturition (the act of giving birth, including time in labour or prior to a caesarean section) and their newborn's weight loss during the first 72 hours postpartum was the primary interest.</p> <p>Methods</p> <p>In this observational cohort study, we collected data about maternal oral and IV fluids during labour or before a caesarean section. Participants (n = 109) weighed their newborns every 12 hours for the first three days then daily to Day 14, and they weighed neonatal output (voids and stools) for three days.</p> <p>Results</p> <p>At 60 hours (nadir), mean newborn weight loss was 6.57% (SD 2.51; n = 96, range 1.83-13.06%). When groups, based on maternal fluids, were compared (≤1200 mls [n = 21] versus > 1200 [n = 53]), newborns lost 5.51% versus 6.93% (p = 0.03), respectively. For the first 24 hours, bivariate analyses show positive relationships between a) neonatal output and percentage of newborn weight lost (r(96) = 0.493, p < 0.001); and b) maternal IV fluids (final 2 hours) and neonatal output (r(42) = 0.383, p = 0.012). At 72 hours, there was a positive correlation between grams of weight lost and all maternal fluids (r(75) = 0.309, p = 0.007).</p> <p>Conclusions</p> <p>Timing and amounts of maternal IV fluids appear correlated to neonatal output and newborn weight loss. Neonates appear to experience diuresis and correct their fluid status in the first 24 hours. We recommend a measurement at 24 hours, instead of birth weight, for baseline when assessing weight change. Because practices can differ between maternity settings, we further suggest that clinicians should collect and analyze data from dyads in their care to determine an optimal baseline measurement.</p

METHOD EVALUATION TO DETERMINE HYDRATION STATES OF TENDONS BY USING MRI

Due to the fact that water content is a determinant of the material properties of tendons and therefore might affect sports performance and the risk of injury, the purpose of this pilot study was to evaluate the reliabilityand sensitivity of a MRI based method to quantify content of a tendon. For this pilot study twenty porcine digital flexor tendons were chosen. All samples were examined on a MR scanner using three 3D ultra-short echo time sequences. With the applied sequences it was possible to determine a decrease in water content of the tendons. In addition, the methods showed a good inter session reliability. Further investigations are needed to improve the upper and lower limit of resolution regarding the physiological hydration state

First Detection of HCO+ Emission at High Redshift

We report the detection of HCO+(1-0) emission towards the Cloverleaf quasar (z=2.56) through observations with the Very Large Array. This is the first detection of ionized molecular gas emission at high redshift (z>2). HCO+ emission is a star formation indicator similar to HCN, tracing dense molecular hydrogen gas (n(H_2) ~= 10^5 cm^{-3}) within star-forming molecular clouds. We derive a lensing-corrected HCO+ line luminosity of L'(HCO+) = 3.5 x 10^9 K km/s pc^2. Combining our new results with CO and HCN measurements from the literature, we find a HCO+/CO luminosity ratio of 0.08 and a HCO+/HCN luminosity ratio of 0.8. These ratios fall within the scatter of the same relationships found for low-z star-forming galaxies. However, a HCO+/HCN luminosity ratio close to unity would not be expected for the Cloverleaf if the recently suggested relation between this ratio and the far-infrared luminosity were to hold. We conclude that a ratio between HCO+ and HCN luminosity close to 1 is likely due to the fact that the emission from both lines is optically thick and thermalized and emerges from dense regions of similar volumes. The CO, HCN and HCO+ luminosities suggest that the Cloverleaf is a composite AGN--starburst system, in agreement with the previous finding that about 20% of the total infrared luminosity in this system results from dust heated by star formation rather than heating by the AGN. We conclude that HCO+ is potentially a good tracer for dense molecular gas at high redshift.Comment: 5 pages, 3 figures, ApJL, in press (accepted May 17, 2006

Finite Temperature Theory of Metastable Anharmonic Potentials

The decay rate for a particle in a metastable cubic potential is investigated in the quantum regime by the Euclidean path integral method in semiclassical approximation. The imaginary time formalism allows one to monitor the system as a function of temperature. The family of classical paths, saddle points for the action, is derived in terms of Jacobian elliptic functions whose periodicity sets the energy-temperature correspondence. The period of the classical oscillations varies monotonically with the energy up to the sphaleron, pointing to a smooth crossover from the quantum to the activated regime. The softening of the quantum fluctuation spectrum is evaluated analytically by the theory of the functional determinants and computed at low $T$ up to the crossover. In particular, the negative eigenvalue, causing an imaginary contribution to the partition function, is studied in detail by solving the Lam\`{e} equation which governs the fluctuation spectrum. For a heavvy particle mass, the decay rate shows a remarkable temperature dependence mainly ascribable to a low lying soft mode and, approaching the crossover, it increases by a factor five over the predictions of the zero temperature theory. Just beyond the peak value, the classical Arrhenius behavior takes over. A similar trend is found studying the quartic metastable potential but the lifetime of the latter is longer by a factor ten than in a cubic potential with same parameters. Some formal analogies with noise-induced transitions in classically activated metastable systems are discussed.Comment: European Physical Journal B EDP Sciences, Societ`a Italiana di Fisica, Springer-Verlag 200

Impact of hexamine addition to a nitrite-based additive on fermentation quality, Clostridia and Saccharomyces cerevisiae in a white lupin-wheat silage

BACKGROUND Nitrite and hexamine are used as silage additives because of their adverse effects on Clostridia and Clostridia spores. The effect of sodium nitrite and sodium nitrite/hexamine mixtures on silage quality was investigated. A white lupin-wheat mixture was treated with sodium nitrite (NaHe0) (900 g t(-1) forage), or mixtures of sodium nitrite (900 g t(-1)) and hexamine. The application rate of hexamine was 300 g t(-1) (NaHe300) or 600 g t(-1) (NaHe600). Additional treatments were the untreated control (Con), and formic acid (FA) applied at a rate of 4 L t(-1) (1000 g kg(-1)). RESULTS Additives improved silage quality noticeably only by reducing silage ammonia content compared with the control. The addition of hexamine to a sodium nitrite solution did not improve silage quality compared with the solution containing sodium nitrite alone. The increasing addition of hexamine resulted in linearly rising pH values (P <0.001) and decreasing amounts of lactic acid (P <0.01). Sodium nitrite based additives were more effective than formic acid in preventing butyric acid formation. Additives did not restrict the growth of Saccharomyces cerevisiae compared to the control. CONCLUSION The addition of hexamine did not improve silage quality compared with a solution of sodium nitrite. (c) 2018 Society of Chemical IndustryPeer reviewe

CO(1-0) in z ≳ 4 Quasar Host Galaxies: No Evidence for Extended Molecular Gas Reservoirs

We present ^(12)CO(J = 1 → 0) observations of the high-redshift quasi-stellar objects (QSOs) BR 1202-0725 (z = 4.69), PSS J2322+1944 (z = 4.12), and APM 08279+5255 (z = 3.91) using the NRAO Green Bank Telescope (GBT) and the MPIfR Effelsberg 100 m telescope. We detect, for the first time, the CO ground-level transition in BR 1202-0725. For PSS J2322+1944 and APM 08279+5255, our observations result in line fluxes that are consistent with previous NRAO Very Large Array (VLA) observations, but they reveal the full line profiles. We report a typical lensing-corrected velocity-integrated intrinsic ^(12)CO(J = 1 → 0) line luminosity of L'_(CO) = 5 × 10^(10) K km s^(-1) pc^2 and a typical total H_2 mass of M(H_2) = 4 × 10^(10) M_☉ for the sources in our sample. The CO/FIR luminosity ratios of these high-z sources follow the same trend as seen for low-z galaxies, leading to a combined solution of log L_(FIR) = (1.39 ± 0.05) log L_(CO) - 1.76. It has previously been suggested that the molecular gas reservoirs in some quasar host galaxies may exhibit luminous, extended ^(12)CO(J = 1 → 0) components that are not observed in the higher J CO transitions. Using the line profiles and the total intensities of our observations and large velocity gradient (LVG) models based on previous results for higher J CO transitions, we derive that emission from all CO transitions is described well by a single gas component in which all molecular gas is concentrated in a compact nuclear region. Thus, our observations and models show no indication of a luminous extended, low surface brightness molecular gas component in any of the high-redshift QSOs in our sample. If such extended components exist, their contribution to the overall luminosity is limited to at most 30%