193 research outputs found
Observation of coasting beam at the HERA Proton--Ring
We present data collected with the HERA-B wire target which prove the
existence of coasting beam at the HERA proton storage ring. The coasting beam
is inherently produced by the proton machine operation and is not dominated by
target effects.Comment: 17 pages (Latex), 12 figures (Enc. Postscript
The problem of 0.999…: Teachers’ school-related content knowledge and their reactions to misconceptions
International audienceThe identity 0.999…=1 connects to a variety of mathematical concepts and therefore allows for an investigation of teachers’ school-related content knowledge (SRCK). This is a facet of their content knowledge (CK) that emphasizes links between school mathematics and the mathematics acquired in tertiary education. Some numerously reported misconceptions and potentially conflicting ideas on 0.999... were presented to secondary school teachers in interviews. Especially in the case of conflicting ideas the relation between SRCK and teachers’ reactions as part of their pedagogical content knowledge (PCK) was examined. The results showed that SRCK, as well as CK in general, is a prerequisite to successfully applying PCK. Further they lead to a discussion of the SRCK model’s use in qualitative research
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The Shield of Sisterhood: Female Relationships and Homosocial Support in the Eighteenth-Century Texts a Dialog Between a Married Woman and a Maid and John Cleland’s Fanny Hill or Memoirs of a Woman of Pleasure
The eighteenth century is known as the period of enlightenment, both as philosophical and sexual. This period saw the re-awakening of erotic literature and art, yet these are often overlooked simply because they are explicit in nature. Within this world of ecstasy and sexual inhibition lies abstract philosophies, reflections of the human psyche, and societal critiques. While often seen as antifeminist works of literature, because of the objectification of women’s bodies, there is evidence to support that these works criticize the mistreatment of women, as well as encourage female pleasure. However, there is untapped potential in this literature as an exploration of human relationships. While the primary content of these works of literature is sexual, there are underlying themes of friendship and comradery, specifically in the anonymously written A Dialog Between a Married Woman and a Maid and John Cleland’s Fanny Hill or Memoirs of a Woman of Pleasure. I argue that these stories are more about the homosocial relationships of women, than the sexually explicit content. While there are detailed accounts of sex, which do play into the story, my primary concern is the interactions between women, and how they are presented in the erotica itself. The stories are not so much about sex as they are about how women must rely on one another to become educated of their place in the world, and how their connection to each other is the strongest bond they have.</p
Inclusive Production Cross Sections from 920 GeV Fixed Target Proton-Nucleus Collisions
Inclusive differential cross sections and
for the production of \kzeros, \lambdazero, and
\antilambda particles are measured at HERA in proton-induced reactions on C,
Al, Ti, and W targets. The incident beam energy is 920 GeV, corresponding to
GeV in the proton-nucleon system. The ratios of differential
cross sections \rklpa and \rllpa are measured to be and , respectively, for \xf . No significant dependence upon the
target material is observed. Within errors, the slopes of the transverse
momentum distributions also show no significant
dependence upon the target material. The dependence of the extrapolated total
cross sections on the atomic mass of the target material is
discussed, and the deduced cross sections per nucleon are
compared with results obtained at other energies.Comment: 17 pages, 7 figures, 5 table
Continuation for thin film hydrodynamics and related scalar problems
This chapter illustrates how to apply continuation techniques in the analysis
of a particular class of nonlinear kinetic equations that describe the time
evolution through transport equations for a single scalar field like a
densities or interface profiles of various types. We first systematically
introduce these equations as gradient dynamics combining mass-conserving and
nonmass-conserving fluxes followed by a discussion of nonvariational amendmends
and a brief introduction to their analysis by numerical continuation. The
approach is first applied to a number of common examples of variational
equations, namely, Allen-Cahn- and Cahn-Hilliard-type equations including
certain thin-film equations for partially wetting liquids on homogeneous and
heterogeneous substrates as well as Swift-Hohenberg and Phase-Field-Crystal
equations. Second we consider nonvariational examples as the
Kuramoto-Sivashinsky equation, convective Allen-Cahn and Cahn-Hilliard
equations and thin-film equations describing stationary sliding drops and a
transversal front instability in a dip-coating. Through the different examples
we illustrate how to employ the numerical tools provided by the packages
auto07p and pde2path to determine steady, stationary and time-periodic
solutions in one and two dimensions and the resulting bifurcation diagrams. The
incorporation of boundary conditions and integral side conditions is also
discussed as well as problem-specific implementation issues
Predominance of exotic and introduced species among sturgeons captured from the Baltic and North Seas and their watersheds, 1981-1999
Sturgeon catches (n = 256) from 1981-1999 reported mainly by commercial fishermen and anglers in German, Polish, and Dutch coastal waters and tributaries were analysed. During the study period, 20 % of catches were reported from coastal waters and 65 % from rivers and estuaries of large river systems, including the Odra, Elbe, Rhine and Weser. The data indicate that, from 1981- 1993, there was a major decline in the Atlantic sturgeon Acipenser sturio L., 1758, and an increase in the total catches of non-indigenous sturgeon species. The Siberian sturgeon Acipenser baerii Brandt, 1869, the Russian sturgeon Acipenser gueldenstaedtii Brandt & Ratzeberg, 1833, and various hybrids dominated. Occasional catches of the white sturgeon Acipenser transmontanus Richardson, 1836 and the sterlet Acipenser ruthenus L., 1758 were also reported. During the study period, significant changes in species composition and distribution of catches were observed. The predominance of non-indigenous sturgeon species is a result of the increasingly intensive sturgeon aquaculture activities in Germany, Poland, and the Netherlands. The most frequently reared species now dominate the catches. In addition to these escapees from fish farms, several intentional releases of sturgeons were reported. The results show that introduced exotic sturgeon species may thrive under certain natural conditions. Therefore, they may interfere with restoration efforts for the native A. sturio, competing for habitat and introducing diseases and hybridization.Se analizaron las capturas de esturiones (n = 256) entre 1981 y 1999 proporcionadas principalmente por pescadores profesionales y deportivos en las costas alemanas, polacas y holandesas, y en los sistemas fluviales que desembocan en ellas. En el periodo de estudio, el 20 % de las capturas correspondió a aguas litorales y el 65 % a ríos y estuarios de los grandes sistemas fluviales, incluidos los ríos Oder, Elba, Rin y Weser. Los datos indican que entre 1981 y 1993 tuvo lugar el mayor declive del esturión atlántico Acipenser sturio L., 1758 y un incremento en las capturas totales de las especies alóctonas de esturiones. Predominaron las capturas de esturión siberiano Acipenser baerii Brandt, 1869, esturión ruso Acipenser gueldenstaedtii Brandt & Ratzeberg, 1833 y varios híbridos. También se registraron capturas ocasionales de esturión blanco Acipenser transmontanus Richardson, 1836 y esterlete Acipenser ruthenus L., 1758. En el periodo de estudio se observaron cambios significativos en la composición de especies y en la distribución de las capturas. El predominio de las especies alóctonas de esturiones es el resultado de las crecientes actividades en la acuicultura intensiva de esturión en Alemania, Polonia y Países Bajos. Las especies cultivadas más frecuentemente dominan ahora las capturas. Además de estas fugas de las piscifactorías, se han registrado varias sueltas intencionadas. Los resultados muestran que las especies de esturiones exóticas introducidas pueden prosperar en ciertas condiciones naturales. Por esta razón, pueden interferir en los esfuerzos de restauración de la especie autóctona A. sturio, compitiendo por el hábitat e introduciendo enfermedades e hibridación.Instituto Español de Oceanografí
Association between Doppler assessment and secondary cesarean delivery for intrapartum fetal compromise in small-for-gestational-age fetuses
PURPOSE: To elucidate the association between arterial and venous Doppler ultrasound parameters and the risk of secondary cesarean delivery for intrapartum fetal compromise (IFC) and neonatal acidosis in small-for-gestational-age (SGA) fetuses. METHODS: This single-center, prospective, blinded, cohort study included singleton pregnancies with an estimated fetal weight (EFW) < 10th centile above 36 gestational weeks. Upon study inclusion, all women underwent Doppler ultrasound, including umbilical artery (UA) pulsatility index (PI), middle cerebral artery (MCA) PI, fetal aortic isthmus (AoI) PI, umbilical vein blood flow (UVBF), and modified myocardial performance index (mod-MPI). Primary outcome was defined as secondary cesarean section due to IFC. RESULTS: In total, 87 SGA pregnancies were included, 16% of which required a cesarean section for IFC. Those fetuses revealed lower UVBF corrected for abdominal circumference (AC) (5.2 (4.5-6.3) vs 7.2 (5.5-8.3), p = 0.001). There was no difference when comparing AoI PI, UA PI, ACM PI, or mod-MPI. No association was found for neonatal acidosis. After multivariate logistic regression, UVBF/AC remained independently associated with cesarean section due to IFC (aOR 0.61 [0.37; 0.91], p = 0.03) and yielded an area under the curve (AUC) of 0.78 (95% CI, 0.67-0.89). A cut-off value set at the 50th centile of UVBF/AC reached a sensitivity of 86% and specificity of 58% for the occurrence of cesarean section due to IFC (OR 8.1; 95% CI, 1.7-37.8, p = 0.003). CONCLUSION: Low levels of umbilical vein blood flow (UVBF/AC) were associated with an increased risk among SGA fetuses to be delivered by cesarean section for IFC
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