A Quantitative Study of Cuprous Oxide Photodismutation

A cuprous oxide emulsion was made using noodling and washing emulsion making techniques. An attempt to use phthalated gelatin and coagulation washing resulted in the formation of cuprous hydroxide and destruction of the phthalated gel molecule and lack of coagulation within the emulsion. Cuprous oxide was also slurried with water and coated onto unglazed porcelain plates. The density-log exposure relationship was linear for the cuprous oxide slurry and non-linear for the cuprous oxide emulsion. The cuprous oxide film gave a speed value twenty-five times greater than that obtained with the slurry. The cuprous oxide dismutation system possesses great variability and little repeatability

How is the invasive gorse Ulex europaeus pollinated during winter? A lesson from its native range

Many examples of plant-insect interactions have shown that selection from herbivores can act on flowering and fruiting phenology. In Ulex europaeus (Fabaceae), escaping seed predation resulted in extended, but variable flowering periods, with some plants flowering from autumn until spring and others flowering only in spring. The present study aims at understanding how gorses can have a high reproductive success during winter despite harsh climatic conditions and low number of pollinators. We measured pollen production, flower size and seed production in spring and winter, and compared the different seasons. The pollination success of flowers was high in both seasons. The flowers produced as much pollen, and were of comparable size in spring and winter, but they stayed open twice as long in winter than in spring. The high pollination rate we observed was thus due to the longer opening period of flowers and the high attractiveness of flowers during winter. However, pod abortion was higher in winter, with 43% of the flowers in winter and 75% in spring producing ripe pods. Antagonistic selective pressures exerted by biotic and abiotic interactions may, therefore, have lead to the observed flowering polymorphism, and allow U.europaeus to thrive in various climates, thus, increasing its invasiveness in different countrie

Seed predation in Ulex europaeus: a geographic and temporal mosaic of interactions

The interactions between plants and their parasites usually involve several species and present high level of variation in space and time. According to the geographic mosaic theory of coevolution, this may lead to population differentiation, large polymorphism and local maladaptation. Here we explore whether the temporal and spatial variation of the interaction between gorse (Ulex europaeus) and its seed predators can explain the polymorphism observed within and among populations of its native range. Indeed, gorse individuals present a polymorphism of flowering and fruiting phenology, and large variability for their susceptibility to seed predation. We performed a regular monitoring of five populations localised in Brittany (France) over five consecutive years. We observed the flowering and fruiting phenology of the gorses, and measured pods infestation rates by their two main seed predators, the weevil Exapion ulicis and the moth Cydia succedana. Flowering phenotypes and between year evolution of parasitism rates were conserved from year to year. Parasitism rates by weevils and moths increased over the fruiting period, and were negatively correlated one to another. Long flowering plants were more attacked by weevils, while short-flowering plants were more attacked by moths. However, the majority of the weevil larvae did not develop into adults, either because they were still at an immature stage at pod maturity, or because they were attacked by a parasitoid wasp. Year-to-year variations in the infestation rates by the two seed predators were very high, and depended on the population but not on the microclimatic conditions. These variations can thus explain the maintenance of the within populations polymorphism of gorse phenology and susceptibility to seed predation

A linear Stark shift in dressed atoms as a signal to measure a nuclear anapole moment with a cold atom fountain or interferometer

We demonstrate theoretically the existence of a linear dc Stark shift of the individual substates of an alkali atom in its ground state, dressed by a circularly polarized laser field. It arises from the electroweak nuclear anapole moment violating P but not T. It is characterized by the pseudoscalar equal to the mixed product formed with the photon angular momentum and static electric and magnetic fields. We derive the relevant left-right asymmetry with its complete signature in a field configuration selected for a precision measurement with cold atom beams. The 3,3 to 4,3 Cs hyperfine-transition frequency shift amounts to 7 $\mu$Hz for a laser power of about 1 kW at 877 nm, E=100 kV/cm and B larger than 0.5 G.Comment: Article, 4 pages, 2 figure

In search of a new form for campus-community relationships

Thesis (M.C.P.)--Massachusetts Institute of Technology, Dept. of Urban Studies and Planning, 2011.Page 119 blank. Cataloged from PDF version of thesis.Includes bibliographical references (p. 110-118).The terms "ivory tower" and "town-gown" have long been used to characterize the relationship between institutions of higher education and the communities in which they reside. While these adversarial phrases reflect the social and physical tension that has historically existed between the two groups, the terms are no longer appropriate as colleges and universities of today are more enlightened, realizing that as fixed and vested institutions, much of their success, and in some cases survival, is dependent on the health of the community in which they reside. The American college campus, where design decisions have come about as a means to engender community and promote learning, is a physical manifestation of the institutional mission and purpose. Therefore, as institutions look beyond their campus edges to consciously engage with their larger community, a shift in the physical representation should follow. In this thesis, I examine the evolution of a new physical form that reflects this changing dynamic by exploring the alignment of the institution's mission to the design and development of the campus edge, where this relationship is most evident. Based on a review of current campus conditions, I develop a sequence of edge conditions based on permeability and relationship between campus and community. I then focus on urban institutions in marginalized neighborhoods that have expanded their mission by embracing their urban setting and engaging with their communities in comprehensive revitalization initiatives. Using two case studies, Clark University and Trinity College, and drawing briefly on several other examples, I consider the relationship between the current and historical mission of the institution and the impact their recent neighborhood revitalization efforts have had on the physical transformation of the campus edges. Applying lessons learned from these efforts, I encourage colleges and universities to reconsider the value of their edges and promote them as an integral part of the overall campus. Finally, I make recommendations to help institutions rethink their campus edges in a way that embraces the evolving community-university dynamic and contributes to the well-being of both their students and surrounding neighborhood.by Anne Bowman.M.C.P

SocioProbe: What, When, and Where Language Models Learn about Sociodemographics

Pre-trained language models (PLMs) have outperformed other NLP models on a wide range of tasks. Opting for a more thorough understanding of their capabilities and inner workings, researchers have established the extend to which they capture lower-level knowledge like grammaticality, and mid-level semantic knowledge like factual understanding. However, there is still little understanding of their knowledge of higher-level aspects of language. In particular, despite the importance of sociodemographic aspects in shaping our language, the questions of whether, where, and how PLMs encode these aspects, e.g., gender or age, is still unexplored. We address this research gap by probing the sociodemographic knowledge of different single-GPU PLMs on multiple English data sets via traditional classifier probing and information-theoretic minimum description length probing. Our results show that PLMs do encode these sociodemographics, and that this knowledge is sometimes spread across the layers of some of the tested PLMs. We further conduct a multilingual analysis and investigate the effect of supplementary training to further explore to what extent, where, and with what amount of pre-training data the knowledge is encoded. Our overall results indicate that sociodemographic knowledge is still a major challenge for NLP. PLMs require large amounts of pre-training data to acquire the knowledge and models that excel in general language understanding do not seem to own more knowledge about these aspects.Comment: Accepted for publication at EMNLP 202

The ‘Institutional Lottery’: institutional variation in the processes involved in accessing late abortion in Victoria, Australia

Despite abortion being decriminalised in Victoria, Australia, access remains difficult, especially at later gestations. Institutions (i.e. health services) place restrictions on the availability of late abortions and/or require additional requirements to be satisfied (e.g. Hospital Termination Review Committee approval), as a consequence of local regulation (i.e. policies and processes determined at the institutional level). This paper reports on the results of 27 interviews with Victorian health professionals about late abortion processes and the operation of Termination Review Committees in Victorian health services, which were analysed thematically. The results reveal the operation of an ‘institutional lottery’ whereby patients' experiences in seeking late abortion services were variable and largely shaped by the institution(s) they found themselves in

Renormalization of earthquake aftershocks

Together with the Gutenberg-Richter distribution of earthquake magnitudes, Omori's law is the best established empirical characterization of earthquake sequences and states that the number of smaller earthquakes per unit time triggered by a main shock decays approximately as the inverse of the time ($1/t^p$, with $p \approx 1$) since the main shock. Based on these observations, we explore the theoretical hypothesis in which each earthquake can produce a series of aftershock independently of its size according to its ``local'' Omori's law with exponent $p=1+\theta$. In this scenario, an aftershock of the main shock produces itself other aftershocks which themselves produce aftershocks, and so on. The global observable Omori's law is found to have two distinct power law regimes, the first one with exponent $p_-=1 - \theta$ for time $t < t^* \sim \kappa^{-1/\theta}$, where $0<1-\kappa <1$ measures the fraction of triggered earthquakes per triggering earthquake, and the second one with exponent $p_+=1 + \theta$ for larger times. The existence of these two regimes rationalizes the observation of Kisslinger and Jones [1991] that the Omori's exponent $p$ seems positively correlated to the surface heat flow: a higher heat flow is a signature of a higher crustal temperature, which leads to larger strain relaxation by creep, corresponding to fewer events triggered per earthquake, i.e. to a larger $\kappa$, and thus to a smaller $t^*$, leading to an effective measured exponent more heavily weighted toward $p_+>1$.Comment: 13 pages, in press in Geophys. Res. Let