Generalized north-south dynamics on the space of geodesic currents

We prove uniform north-south dynamics type results for the action of $\varphi\in Out(F_{N})$ on the space of projectivized geodesic currents $\mathbb{P}Curr(S)=\mathbb{P}Curr(F_{N})$, where $\varphi$ is induced by a pseudo-Anosov homeomorphism on a compact surface S with boundary such that $\pi_{1}(S)=F_{N}$. As an application, we show that for a subgroup $H\le Out(F_N)$, containing an iwip, either $H$ contains a hyperbolic iwip or $H$ is contained in the image in $Out(F_N)$ of the mapping class group of a surface with a single boundary component.Comment: 20 pages, 2 figures, v3: Minor correction

An intersection functional on the space of subset currents on a free group

Kapovich and Nagnibeda introduced the space $\mathcal{S} {\rm Curr}(F_N)$ of subset currents on a free group $F_N$ of rank $N\geq 2$, which can be thought of as a measure-theoretic completion of the set of all conjugacy classes of finitely generated subgroups of $F_N$. We define a product $\mathcal{N} (H,K)$ of two finitely generated subgroups $H$ and $K$ of $F_N$ by the sum of the reduced rank $\overline{\rm rk}(H\cap gKg^{-1})$ over all double cosets $HgK\ (g\in F_N)$, and extend the product$\mathcal{N}$to a continuous symmetric$\mathbb{R}_{\geq 0}$-bilinear functional$\mathcal{N} \colon \mathcal{S} {\rm Curr} (F_N)\times \mathcal{S} {\rm Curr} (F_N)\to \mathbb {R}_{\geq 0}$. We also give an answer to a question presented by Kapovich and Nagnibeda. The definition of$\mathcal{N}$originates in the Strengthened Hanna Neumann Conjecture, which has been proven by Mineyev and can be stated as follows:$\mathcal{N} (H,K)\leq \overline{{\rm rk}} (H) \overline{\rm rk} (K)$holds for any finitely generated subgroups$H$and$K$of$F_N$. As a corollary to our theorem, this inequality is generalized to the inequality for subset currents.Comment: 27 pages (updated version). arXiv admin note: text overlap with arXiv:1105.5742 by other author

Congenital arterio-venous fistulae and other vascular anomalies

The object of this thesis is to present an extensive survey of some rare congenital vascular anomalies, with special reference to arterio- venous fistulae. Interest was first aroused in those cases which showed a marked hypertrophy of a limb, along with numerous angiomata and varicose veins. Investigations revealed that these features had been described both in the presence and in the absence of arteriovenous fistulae, and, further, that arterio -venous fistulae could be found in the absence of hypertrophy or angiomata. Illustrating many of the varied and bizarre manifestations, a series of twelve cases has been examined and will now be reported, the presence of arterio -venous fistulae being found in nine cases, but not in the other three. These cases will, there - fore, be described in considerable detail, along with brief reports on two other cases which have come to my notice.Though the lesions under review are congenital, there has been much difference of opinion as to the underlying pathology, a haemangioma, indicating a true tumour, being maintained by some, and an actual maldevelopment of the vascular system being supported by others. Such opposing views are shown by the varied and confused nomenclature, the following being examples of names which might be applied to my own series of cases, and which have been freely used in the past : - arterio- venous aneurysm, anastomoses or fistulae; cirsoid or racemose aneurysm; aneurysm by anastomosis; aneurysmal varix; many varieties of haemangioma or naevus, such as cavernous, pulsating, plexiform, arterial or venous; haemangioma of bone or 'muscle; angiosarcoma; phlebarteriectasis; phiebec Itasis; cavernoma; haemangiectatic hypertrophy; hems hypertrophy; generalised angiomatosis

Doctor of Philosophy

dissertationPrimary breast carcinoma is the most common type of cancer among women and radiodermatitis a frequent complication of treatment. The study aims were to examine the feasibility of measurements of radiodermatitis and gain a better understanding of quality of life (QOL) among 40 women with grade 0-III breast carcinoma receiving radiotherapy at a community cancer center. Study design feasibility, clinician-measured breast length, and multiple assessments of breast radiodermatitis were explored in a pilot study. Maximum radiodermatitis score significantly correlated with breast length (p =.04), and with the following breast areas: upper inner quadrant (p=.04), upper lateral quadrant (p=.02), and lower lateral quadrant (p=.02), inframammary fold (p=.001). Clinician-measured breast lengths and participant-reported bra cup sizes were discordant estimates of breast size. Change in skin-related and global QOL between baseline and at week 5 on radiotherapy was measured using the Dermatology Life Quality Index (DLQI) and the Quality of Life Instrument-Breast Cancer Patient Version. The relationship between, and factors associated with, skin-related and global QOL were examined. In general, skinrelated and global QOL were highly correlated. Skin-related QOL changed profoundly (M=.40, SD=1.19; versus M=3.88, SD=3.55, t(-6.32), p<.001) while global QOL did not change (M=296.90, SD=74.18; versus M=292.55, SD=72.23, t(60), p=.55) between baseline and five weeks on radiotherapy. We initiated the validation of the DLQI when used to measure skin-related QOL in breast radiodermatitis. Thirty-one (78%) participants provided narrative feedback on how the experience represented by each DLQI item impacted her life. Agreement between DLQI ratings and coded narratives ranged from 71% to 98%. Aside from work and study, the DLQI subscales demonstrated good internal consistency, α =.84. Content analysis was implemented to describe 28 participants' narrative response to an open-ended question about the most important DLQI item. Analysis of 60 narratives led to the identification of six themes: perspectives on having radiodermatitis, sensations caused by radiodermatitis, knowledge and preparation for radiotherapy, prevention of radiodermatitis, emotions induced by skin changes, and physical appearance of the breast skin. Results suggest radiodermatitis has a significant impact on skin-related QOL; breast length measurements and multiple assessments of radiodermatitis may improve breast cancer research in this area

Colloidal particle motion as a diagnostic of DNA conformational transitions

Tethered particle motion is an experimental technique to monitor conformational changes in single molecules of DNA in real time, by observing the position fluctuations of a micrometer-size particle attached to the DNA. This article reviews some recent work on theoretical problems inherent in the interpretation of TPM experiments, both in equilibrium and dynamical aspects.Comment: 19pp. Accepted for publication in Curr Op Colloid Interf Scienc

Curr Biol

Geosmin is one of the most recognizable and common microbial smells on the planet. Some insects, like mosquitoes, require microbial-rich environments for their progeny, whereas for other insects such microbes may prove dangerous. In the vinegar fly Drosophila melanogaster, geosmin is decoded in a remarkably precise fashion and induces aversion, presumably signaling the presence of harmful microbes [1]. We have here investigated the effect of geosmin on the behavior of the yellow fever mosquito Aedes aegypti. In contrast to flies, geosmin is not aversive but mediates egg-laying site selection. Female\ua0mosquitoes likely associate geosmin with microbes, including cyanobacteria consumed by larvae [2], who also find geosmin-as well as geosmin-producing cyanobacteria-attractive. Using in\ua0vivo multiphoton calcium imaging from transgenic PUb-GCaMP6s mosquitoes, we show that Ae. aegypti code geosmin in a qualitatively similar fashion to flies, i.e., through a single olfactory channel with a high degree of sensitivity for this volatile. We further demonstrate that geosmin can be used as bait under field conditions, and finally, we show that geosmin, which is both expensive and difficult to obtain, can be substituted by beetroot peel extract, providing a cheap and viable potential mean for mosquito control and surveillance in developing countries.R01 DC013693/DC/NIDCD NIH HHSUnited States/R21 AI137947/AI/NIAID NIH HHSUnited States/U01 CK000510/CK/NCEZID CDC HHSUnited States/2020-04-09T00:00:00Z31839454PMC714481211936vault:4329

Curr Biol

Just as organ size typically increases with body size, the size of intracellular structures changes as cells grow and divide. Indeed, many organelles, such as the nucleus [1, 2], mitochondria [3], mitotic spindle [4, 5], and centrosome [6], exhibit size scaling, a phenomenon in which organelle size depends linearly on cell size. However, the mechanisms of organelle size scaling remain unclear. Here, we show that the size of the nucleolus, a membraneless organelle important for cell-size homeostasis [7], is coupled to cell size by an intracellular phase transition. We find that nucleolar size directly scales with cell size in early C.\uc2\ua0elegans embryos. Surprisingly, however, when embryo size is altered, we observe inverse scaling: nucleolar size increases in small cells and decreases in large cells. We demonstrate that this seemingly contradictory result arises from maternal loading of a fixed number rather than a fixed concentration of nucleolar components, which condense into nucleoli only above a threshold concentration. Our results suggest that the physics of phase transitions can dictate whether an organelle assembles, and, if so, its size, providing a mechanistic link between organelle assembly and cell size. Since the nucleolus is known to play a key role in cell growth, this biophysical readout of cell size could provide a novel feedback mechanism for growth control.1DP2GM105437-01/DP/NCCDPHP CDC HHS/United StatesDP2 GM105437/GM/NIGMS NIH HHS/United StatesP40 OD010440/OD/NIH HHS/United States2016-03-02T00:00:00Z25702583PMC434817