Generalization of a Hadamard type inequality for permanents

This paper is devoted to a generalization of a Hadamard type inequality for the permanent of a complex square matrix. Our proof is based on a non-trivial extension of a technique used in Carlen, Lieb and Loss (Methods and Applications of Analysis 13 (1) (2006) 1-17). We give an application to coefficients of products of linear forms and show some auxiliary inequalities, which might be of independent interest.Comment: 20 page

Righteousness, Reservation, Remembrance: Freedom-Loving Whites, Freedom-Seeking Blacks, and the Societies They Formed in Adams County

On the border between slave society and free society a collection of ideologies mixed. The residents of Adams County, even before its inception on January 22, 1800, lived in a state of division that swirled and crashed against the omnipresent slavery conundrum. The New World Renaissance swept through Adams County in the 1830s bringing schools, public works, businesses, and most culturally significant, new ideas. These ideas would prove to be the fount from which flowed the waters of reform. As the first settlers had made good use of the physical creeks and streams that dotted their pastoral landscape, so too would they put to good use the waters of reform welling up all around them. From temperance to anti-masonry, these reform movements would lend a helping hand in the creation of the most socially progressive institution the county could harbor: an abolition society. However, the Adams County Anti-Slavery Society would be stunted along the way, allowing external pressures to beat back its radicalism. Because of this, the Adams County Anti-Slavery Society never fully realized its potential as a reform movement and degenerated into a Saturday Club, where radical statements might be made but never acted upon. It was here that a split occurred. There were two common paths that the membership took as they came to realize the fate of their anti-slavery organization. The first of these paths was acceptance. Many of the members had been in reform societies of some type before the Anti-Slavery Society. A large group of these individuals decided that a moderated reformism was better than no reformism and they perpetuated a version of the original society, keeping it well stocked and gentlemanly. The other path, taken by those touched with a deep fervor for reform culminates in the use of extra-legal means. The Underground Railroad. This path also bred a strong tradition of communal memory spun from its participant\u27s perceived failure at abolition. This paper will discuss the machinations, myths, and memory of not only the Anti-Slavery Society, but also of the Underground Railroad, Yellow Hill community, and the people who made these organizations work

Entropic forces in Brownian motion

The interest in the concept of entropic forces has risen considerably since E. Verlinde proposed to interpret the force in Newton s second law and Gravity as entropic forces [1]. Brownian motion, the motion of a small particle (pollen) driven by random impulses from the surrounding molecules, may be the first example of a stochastic process in which such forces are expected to emerge. In this note it is shown that at least two types of entropic force can be identified in the case of 3D Brownian motion (or random walk). This yields simple derivations of known results of Brownian motion, Hook s law and, applying an external (non-radial) force, Curie s law and the Langevin-Debye equation.Comment: 11 pages, 1 figur

Habitat selection and reproduction of red-backed shrikes (Lanius collurio) in relation to abundance of potential avian nest predators

Many studies of farmland bird species have related abundance of species to different habitat variables, whereas few studies have incorporated the effects of predation on habitat selection. However, it is generally assumed that prey species select habitat with low risk of predation, but the consequences for prey population growth of this avoidance behaviour remain largely unknown. During seven years, I studied habitat selection and reproduction of red-backed shrikes (Lanius collurio), a passerine bird inhabiting shrub-rich grasslands, in relation to abundance of potential avian nest predators (i.e. corvids). Results from several experiments with artificial nests designed to mimic redbacked shrike nests suggest that magpies (Pica pica) are the most frequent nest predators on artificial nests. To a lesser extent also hooded crows (Corvus corone cornix) and jays (Garrulus glandarius) depredated artificial nests. The results from the artificial nest experiments were validated through the patterns of predation of real red-backed shrike nests, as these were depredated at faster rates close to nests of magpies and hooded crows than elsewhere in the landscape. Furthermore, red-backed shrikes avoided to breed in grasslands located close to magpie and hooded crow nests. In addition, at the landscape scale, between-year changes in the spatial distribution of breeding magpies and hooded crows were followed by inverse changes in the distribution of red-backed shrikes. For example, when the distance to closest magpie nest decreased, or when the number of magpie nests within 1 km2 increased, red-backed shrikes avoided to breed in that area, despite a high abundance of suitable grasslands with a history of breeding red-backed shrikes. The behaviour of avoiding corvids was adaptive, as red-backed shrikes breeding far away from magpies and hooded crows experienced lower risk of nest predation than pairs breeding close to these corvids. My results partly contradict results of other studies, which have suggested that nest predators may not influence breeding habitat selection of farmland birds. Nevertheless, my results suggest that interspecific interactions such as nest predation may force individual birds to breed in habitats of lower quality. It is therefore possible that the observed population increases of many generalist predator species (e.g. corvids) may have contributed to the decline of farmland birds both in a direct way (i.e. low breeding success) and in an indirect way (i.e. successful nests produce fledglings of lower quality). Further studies on other populations and species are needed before the finer details of how nest predation may regulate populations of farmland birds may be fully understood.Viele Untersuchungen zu Brutvogelarten in der Agrarlandschaft setzen die Abundanzen einzelner Arten in Beziehung zu bestimmten Eigenschaften (Parametern) der Landschaft. Nur wenige Studien berücksichtigen interspezifische Wechselwirkungen, wie etwa den Einfluss von Prädatoren auf die Habitatwahl. Im Allgemeinen wird angenommen, dass Beutetierarten ein Habitat mit geringem Prädationsrisiko bevorzugen, wobei allerdings die populationsbiologischen Konsequenzen für Beutetiere mit einem solchen Meidungsverhalten weitgehend unbekannt sind. Die Habitatwahl und Reproduktion des Neuntöters (Lanius collurio), eines in buschreichem Grünland lebenden Singvogels (Passeriformes), wurde über 7 Jahre hinweg untersucht. Dabei standen Einflüsse von potentiellen Gelegeräubern, insbesondere Corviden, im Mittelpunkt der Untersuchung. Verschiedene Experimente mit künstlichen „Neuntöternestern“ ergaben, dass hauptsächlich Elstern (Pica pica) als Gelegeprädatoren auftreten. Daneben konnten aber auch mit geringerer Intensität Nebelkrähen (Corvus corone cornix) und Eichelhäher (Garrulus glandarius) als Nesträuber nachgewiesen werden. Die Ergebnisse der Experimente mit Kunstnestern bestätigten sich im Freiland dahingehend, dass Neuntöter bei der Brutplatzwahl die Nähe von Elstern und Nebelkrähen mieden. Darüber hinaus fand sich über die Jahre eine gegenläufige Beziehung zwischen den räumlichen Verteilungsmustern des Neuntöters und denen brütender Elstern und Nebelkrähen. Nahm etwa die Distanz zur nächsten brütenden Elster von einem zum nächsten Jahr hin ab, oder stieg die Brutdichte der Elster im Umkreis von einem km2 an, so wurden selbst gut geeignete, traditionelle Bruthabitate verlassen. Dieses Meidungsverhalten gegenüber Rabenvögeln hat einen hohen adaptiven Wert: Neuntöter, die in größerer Entfernung zu besetzten Elstern- und Rabenkrähennestern brüten, tragen ein geringeres Prädationsrisiko als in Nachbarschaft brütende Individuen. Die vorliegenden Ergebnisse widersprechen teilweise anderen Studien, wonach die Habitatwahl von Vogelarten der Kulturlandschaft nicht von Prädatoren beeinflusst wird. Darüber hinaus legen die Ergebnisse der vorliegenden Arbeit nahe, dass interspezifische Interaktionen (z.B. Risiko der Gelegeprädation) Individuen durchaus dazu veranlassen können, in Bruthabitate minderer Qualität zu wechseln. Es ist daher möglich, dass die festgestellten Populationszunahmen bei zahlreichen generalistischen Prädatoren (z. B. Corviden) sowohl direkt (z.B. geringerer Bruterfolg durch Prädation) als auch indirekt (z.B. Produktion von Küken geringerer Qualität in suboptimalen Habitaten) zur Abnahme von Vogelarten der Agrarlandschaft beitragen. Allerdings sind hier weitere detaillierte Studien an anderen Populationen und Arten der Agrarlandschaft notwendig um genauere Angaben zu einer möglichen Populationsregulation durch Nestprädatoren machen zu können

Bilingual Education: The Hispanic Response to Unequal Educational Opportunity

Discusses the nature of the right to bilingual education, the nature of the program that must be provided, who is directly responsible for it, and the potential conflict between court-mandated desegregation and the support of bilingual programs

How important is geography for agglomeration?

The economic geography literature distinguishes between two types of reasons for economic agglomeration. Regional concentration of economic activity can be attributed to 'first nature' meaning geographic advantages and disadvantages given by nature or to 'second nature' meaning agglomeration economies by the interaction of economic agents. Several recent studies tried to estimate the relative importance of the two types of explanation. Most of these studies seem to exaggerate the importance of natural advantages because of loose definitions of geography. We describe geography by a small set of non-economic variables and estimate their importance for agglomeration in Germany. We find that about one third of the agglomeration of economic activity can be attributed to geography.