676 research outputs found
A phenotypic and genetic analysis of energy balance in dairy cows
In dairy cows, the failure or unwillingness to eat sufficient in early lactation when yield is high leads
to a state known as negative energy balance (NEB). In this state, cows mobilise body tissue mostly in
the form of body lipid in order to make up the difference in energy available from feed ingested and
that required to sustain obligatory requirements, such as maintenance, and milk production. A large
NEB is an undesirable state since it is associated with increased disease and reduced fertility.Body lipid content can be predicted from visual assessment of the tailhead of cows using a system
known as body condition scoring (BCS). Changes in this score over time can therefore be used to
predict body lipid changes. I investigated the feasibility of automating the process of collecting
condition score using a digital camera and laser lights. The correlation between CS and shape over the
tail-head was 0.55 suggesting that it may be possible in future to include digital images in an
automated and integrated dairy farm management system.Using random regression analysis, I analysed changes in milk production, feed intake, liveweight and
BCS over one to three lactations and calculated energy balance from these daily predictions. These
analyses showed that energy balance can be predicted from body measurements without the need to
measure feed intake making it practical to use nationally. Using these techniques enabled the genetic
analysis of large volumes of field data to predict daily breeding values for energy balance for 1250
progeny test sires. Substantial genetic variation was found in energy balance profiles. The mean total
daughter body energy loss at day 305 of lactation was 779 MJ (SD=224 MJ), equivalent in energy
terms to about 189 kg milk. Future selection indices may contain an adjustment for the amount of
body energy used to support the milk production of a bullsâ daughters leading to a more complete
assessment of the utility of a bull.Analysis of data from the Langhill Dairy Research Centre demonstrated that there are differences in
the way dairy cows of differing genetic merit for production mobilise body lipid to support lactation
and that the amount of concentrate fed also affects the recovery of lost body lipid. Select cows
contained about 3200 MJ less energy than control cows at the end of the third lactation and lose and
gain body lipid in a cyclical way. Parameters of these curves may be used in future selection indices to
allow selection of genotypes that have profiles of body lipid loss and gain commensurate with high
yields and long herd life. This may also be useful in future when selection indices contain more traits
and farmers and advisors tailor their management to suit the type of cow. It may also provide guidance
on how future selection indices should be developed to incorporate traits such as body lipid, traits that
enable the robust cow to thrive over many high yielding lactations
Specific heat anomalies of open quantum systems
The evaluation of the specific heat of an open, damped quantum system is a
subtle issue. One possible route is based on the thermodynamic partition
function which is the ratio of the partition functions of system plus bath and
of the bath alone. For the free damped particle it has been shown, however,
that the ensuing specific heat may become negative for appropriately chosen
environments. Being an open system this quantity then naturally must be
interpreted as the change of the specific heat obtained as the difference
between the specific heat of the heat bath coupled to the system degrees of
freedom and the specific heat of the bath alone. While this difference may
become negative, the involved specific heats themselves are always positive;
thus, the known thermodynamic stability criteria are perfectly guaranteed. For
a damped quantum harmonic oscillator, instead of negative values, under
appropriate conditions one can observe a dip in the difference of specific
heats as a function of temperature. Stylized minimal models containing a single
oscillator heat bath are employed to elucidate the occurrence of the anomalous
temperature dependence of the corresponding specific heat values. Moreover, we
comment on the consequences for the interpretation of the density of states
based on the thermal partitionfunction.Comment: 7 pages, 6 figures, new title and some modifications of the main tex
Afrikanische Soldaten im französisch besetzten Vorarlberg 1945/46
Vorarlberg wurde hauptsÀchlich von marokkanischen Kolonialtruppen der französischen Armee befreit. Die vorliegende Arbeit behandelt den Aufenthalt dieser Soldaten in Vorarlberg
insbesondere unter dem Aspekt welche Diskurse ĂŒber diese Soldaten in der
Vorarlberger Bevölkerung und von Seiten französischer Offiziere prÀsent waren. Daneben gehe ich auch den soziale
Hintergrund der marokkanischen Soldaten und auf die Funktionsweise der
französischen Kolonialarmee ein.
Ich ziehe sowohl publizierte Quellen wie Memoiren französischer GenerÀle, Zeitschriften und Zeitungen als auch Quellen aus Vorarlberger Archiven sowie dem Archiv der französischen Armee heran.
Die französische Armee war ein von systematischer Diskriminierung gegenĂŒber den
kolonisierten Soldaten in allen Bereichen des militÀrischen Leben geprÀgtes System.
Die voralberger Sichtweisen ĂŒber marokkanischen Soldaten zeigen insbesondere zu
den in interner Korrespondenz der Armee geĂ€uĂerten Meinungen französischer Offiziere starke Parallelen auf. In beiden ist die
Infantilisierung der Kolonialsoldaten ein wichtiges Instrument der Konstruktion ihrer
eigenen Ăberlegenheit. Auch die Ablehnung von Beziehungen zwischen
marokkanischen Soldaten und französischen bzw. österreichischen Frauen ist in beiden
Diskursen stark prÀsent.
Gleichzeitig gibt es eine starke Diskrepanz zwischen den Darstellungen in Publikationen der französischen Armee bzw. Offizieren dieser und in der internen Kommunikation der Armee. WÀhrend bei ersteren am Ideal der mission
civilicatrice festgehalten wird und Frankreich im allgemeinen bzw. die französische
Armee im speziellen als Motor der Weiterentwicklung der autochthonen Bevölkerung
Afrikas dargestellt wird, kommt in der internen Kommunikation des französischen
Generalstabs fĂŒr Marokko zum Ausdruck, dass eine Weiterentwicklung der Soldaten
komplett unerwĂŒnscht ist, da man befĂŒrchtete, dass jegliche Horizonterweiterung der
Kolonialsoldaten den militÀrischen Wert der Kolonialarmee zerstören konnte
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