5,268 research outputs found
Thermodynamically Stable One-Component Metallic Quasicrystals
Classical density-functional theory is employed to study finite-temperature
trends in the relative stabilities of one-component quasicrystals interacting
via effective metallic pair potentials derived from pseudopotential theory.
Comparing the free energies of several periodic crystals and rational
approximant models of quasicrystals over a range of pseudopotential parameters,
thermodynamically stable quasicrystals are predicted for parameters approaching
the limits of mechanical stability of the crystalline structures. The results
support and significantly extend conclusions of previous ground-state
lattice-sum studies.Comment: REVTeX, 13 pages + 2 figures, to appear, Europhys. Let
Secrets of Sex and Innocence in Memoirs of a Woman of Pleasure: A Profile of Purity Using Three Common Philosophies
John Cleland’s 1749 text Memoirs of a Woman of Pleasure has squeezed its way into popular culture by bringing to life the risqué sexual adventures of its female protagonist, Fanny Hill. To the narrator, sexuality is a tool of survival and influence. Deeper readings into Memoirs reveal underlying threads of purity and virginity, which, despite her sexual encounters, Fanny constantly strives to retain. By analyzing common works of human and social philosophy – specifically those of John Locke, Sigmund Freud, and Jeremy Bentham – the paper scrutinizes Fanny as a paragon of innocence regardless of her actions. While taking into consideration the historical context of Fanny’s profession – specifically its social implications – empirical, psychoanalytic, and utilitarian theories are used to reappraise the common indictment of Fanny as a mere sex symbol. The works of Locke, Freud, and Bentham are employed to label her as an empowered female figure whose origins are causal of her sexual activity, and who gradually rehabilitates herself through sex to retain purity in the context of eighteenth-century social ideologies
Evaluation of Cotton Management Decisions: Cover Crops, Weed Control, and Injured Stands
Herbicide-resistant weed species have altered the challenges faced by Tennessee cotton (Gossypium hirsutum, L.) producers. While the weed control and environmental benefits of cover crops have been well-documented, the integration of cover crops into cotton production systems has presented management challenges. In-season broadcast postemergence weed control options are limited in cotton. Furthermore, off-target movement of 2,4-D and dicamba can result in additional management challenges if susceptible cotton is injured. Studies were conducted from 2018 to 2021 to evaluate: 1) cotton response to cover crop termination timings and methods; 2) postemergence weed control programs in cotton without the use of glyphosate; 3) the relationship between auxin injury, in-season reflectance data, and yield penalties; and 4) the effects of synthetic auxin exposure on yield components of cotton. Cover crop termination timings and methods impacted early season cotton growth, but yields were ultimately not affected. Postemergence control of weed species was generally greater with multiple POST applications compared to a single POST application but no herbicide program provided greater than 80% annual grass control 21 d after late-POST application. Auxin related injury and yield penalties may be better predicted following exposure during vegetative growth compared to exposure during reproductive growth. Exposure to 2,4-D caused more severe impacts to cotton than exposure to dicamba, but auxin application rate and timing impacted yield components and partitioning. Results from these studies will support a more sustainable production system through improved management of cover crops, selection of herbicide programs, and understanding of the scope and severity of off-target movement of 2,4-D and dicamba
Electroneutrality and Phase Behavior of Colloidal Suspensions
Several statistical mechanical theories predict that colloidal suspensions of
highly charged macroions and monovalent microions can exhibit unusual
thermodynamic phase behavior when strongly deionized. Density-functional,
extended Debye-H\"uckel, and response theories, within mean-field and
linearization approximations, predict a spinodal phase instability of charged
colloids below a critical salt concentration. Poisson-Boltzmann cell model
studies of suspensions in Donnan equilibrium with a salt reservoir demonstrate
that effective interactions and osmotic pressures predicted by such theories
can be sensitive to the choice of reference system, e.g., whether the microion
density profiles are expanded about the average potential of the suspension or
about the reservoir potential. By unifying Poisson-Boltzmann and response
theories within a common perturbative framework, it is shown here that the
choice of reference system is dictated by the constraint of global
electroneutrality. On this basis, bulk suspensions are best modeled by
density-dependent effective interactions derived from a closed reference system
in which the counterions are confined to the same volume as the macroions.
Linearized theories then predict bulk phase separation of deionized suspensions
only when expanded about a physically consistent (closed) reference system.
Lower-dimensional systems (e.g., monolayers, small clusters), depending on the
strength of macroion-counterion correlations, may be governed instead by
density-independent effective interactions tied to an open reference system
with counterions dispersed throughout the reservoir, possibly explaining
observed structural crossover in colloidal monolayers and anomalous
metastability of colloidal crystallites.Comment: 12 pages, 5 figures. Discussion clarified, references adde
Neuroimaging evidence implicating cerebellum in support of sensory/cognitive processes associated with thirst.
Recent studies implicate the cerebellum, long considered strictly a motor control structure, in cognitive, sensory, and affective phenomenon. The cerebellum, a phylogenetically ancient structure, has reciprocal ancient connections to the hypothalamus, a structure important in vegetative functions. The present study investigated whether the cerebellum was involved in vegetative functions and the primal emotions engendered by them. Using positron emission tomography, we examined the effects on the cerebellum of the rise of plasma sodium concentration and the emergence of thirst in 10 healthy adults. The correlation of regional cerebral blood flow with subjects' ratings of thirst showed major activation in the vermal central lobule. During the development of thirst, the anterior and posterior quadrangular lobule, lingula, and the vermis were activated. At maximum thirst and then during irrigation of the mouth with water to alleviate dryness, the cerebellum was less activated. However, 3 min after drinking to satiation, the anterior quadrangular lobule and posterior cerebellum were highly activated. The increased cerebellar activity was not related to motor behavior as this did not occur. Instead, responses in ancient cerebellar regions (vermis, fastigal nucleus, archicerebellum) may be more directly related to vegetative and affective aspects of thirst experiences, whereas activity in neocerebellar (posterior) regions may be related to sensory and cognitive aspects. Moreover, the cerebellum is apparently not involved in the computation of thirst per se but rather is activated during changes in thirst/satiation state when the brain is "vigilant" and is monitoring its sensory systems. Some neocerebellar activity may also reflect an intentionality for gratification by drinking inherent in the consciousness of thirst
Business strategy driven IT systems for engineer-to-order and make-to-order manufacturing enterprises
This thesis reports research into the specification and implementation of an Information
Technology (IT) Route Map. The purpose of the Route Map is to enable rapid design
and deployment of IT solutions capable of semi-automating business processes in a
manufacturing enterprise. The Map helps structure transition processes involved in
“identification of key business strategies and design of business processes” and “choice
of enterprise systems and supporting implementation techniques”. Common limitations
of current Enterprise Resource Planning (ERP) systems are observed and incorporated
as Route Map implications and constraints.
Scope of investigation is targeted at Small to Medium Sized Enterprises
(SMEs) that employ Engineer-To-Order (ETO) and Make-To-Order (MTO) business
processes. However, a feature of the Route Map is that it takes into account
contemporary business concerns related to “globalisation”, “mergers and acquisitions”
and “typical resource constraint problems of SMEs”.
In the course of the research a “Business Strategy Driven IT System Concept”
was conceived and examined. The main purpose of this concept is to promote the
development of agile and innovative business activity in SMEs. The Road Map
encourages strategy driven solutions to be (a) specified based on the use of emerging
enterprise engineering theories and (b) implemented and changed using componentbased
systems design and composition techniques.
Part-evaluation of the applicability and capabilities of the Road Map has been
carried out by conducting industrial survey and case study work. This assesses
requirements of real industrial problems and solutions. The evaluation work has also
been enabled by conducting a pilot implementation of the thesis concepts at the
premises of a partner SME
Charge Renormalization, Effective Interactions, and Thermodynamics of Deionized Colloidal Suspensions
Thermodynamic properties of charge-stabilised colloidal suspensions depend
sensitively on the effective charge of the macroions, which can be
substantially lower than the bare charge in the case of strong
counterion-macroion association. A theory of charge renormalization is
proposed, combining an effective one-component model of charged colloids with a
thermal criterion for distinguishing between free and associated counterions.
The theory predicts, with minimal computational effort, osmotic pressures of
deionized suspensions of highly charged colloids in close agreement with
large-scale simulations of the primitive model.Comment: 15 pages, 7 figure
The Ursinus Weekly, February 12, 1940
College will observe Founders\u27 Day Thursday • Dr. Beardwood dies of heart ailment in sixty-ninth year • Color presentation tonight at 6:30 • Party to complete Lorelei festivities • Dr. McClure to be honored by Temple • Debaters schedule five home meets • Dr. Anderson discusses Russia\u27s foreign policy • Reginald Singh to speak at vespers this Sunday • Tickets on sale for Jan Peerce recital • 73 students set new record for B list • Ursinus library was originally housed in Derr and Stine; present edifice was completed in 1923 at cost of $95,000 • Sentiment in favor of third term increasing • McClure\u27s Letters of John Chamberlain presented for public and scholars alike • Dr. McClure, Helfferich honored by colleagues • Muhlenberg quintet tops bears, 45-40; Dickinson wins, 42-36, on Friday night • Bear matmen lose meet to Haverford • F. and M. dribblers lead league race • Life saving class will start soon • Co-ed courtsters down Swarthmore • Frosh basketball team loses to Muhlenberg • Penn professor to speak on Latin-America before IRChttps://digitalcommons.ursinus.edu/weekly/1833/thumbnail.jp
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