Spatially regularized estimation for the analysis of DCE-MRI data

Competing compartment models of different complexities have been used for the quantitative analysis of Dynamic Contrast-Enhanced Magnetic Resonance Imaging data. We present a spatial Elastic Net approach that allows to estimate the number of compartments for each voxel such that the model complexity is not fixed a priori. A multi-compartment approach is considered, which is translated into a restricted least square model selection problem. This is done by using a set of basis functions for a given set of candidate rate constants. The form of the basis functions is derived from a kinetic model and thus describes the contribution of a specific compartment. Using a spatial Elastic Net estimator, we chose a sparse set of basis functions per voxel, and hence, rate constants of compartments. The spatial penalty takes into account the voxel structure of an image and performs better than a penalty treating voxels independently. The proposed estimation method is evaluated for simulated images and applied to an in-vivo data set

Effects of microzooplankton and mixotrophy in an experimental planktonic food web

Microzooplankton have received increased attention as an important trophic link between the microbial loop and calanoid copepods. On the basis of food size spectra overlap in some microzooplankton groups and calanoid copepods, however, such microzooplankton could function as competitors rather than as food for calanoid copepods (intraguild prey). Mixotrophic flagellates presumably represent a link between the microbial loop and the micro and mesozooplankton. We investigated the effects of microzooplankton and mixotrophy by altering the presence of a heterotrophic dinoflagellate and of a mixotrophic nanoflagellate in artificial food webs with calanoid copepods as terminal consumers. Overall system productivity was manipulated by two levels of nutrient enrichment. The heterotrophic dinoflagellate drastically reduced the nanophytoplankton and enhanced the reproduction of the copepods, suggesting that its role as a competitor is negligible compared to its function as a trophic link. In spite of the presence of heterotrophic nanoflagellates, the mixotroph had a strong negative effect on the picophytoplankton and (presumably) on bacterial biomass. At the same time, the mixotroph enhanced the atomic C:N ratio of the seston biomass, indicating a higher efficiency in overall primary production. Copepod reproduction was enhanced in the presence of the mixotrophic nanoflagellate. Results did not support predictions of the intraguild predation theory: The ratios of the intraguild predators and their preys were not affected by overall system productivit

forschung@h-brs: Forschung an der Hochschule Bonn-Rhein-Sieg WS 2007/2008 – WS 2009/2010

Mit der Broschüre "forschung@h-brs" legt die Hochschule Bonn-Rhein-Sieg erstmals einen Bericht über ihre Forschungsaktitiväten vor. Er belegt die Zeit der akademischen Jahre 2007/08 bis 2009/10

Spontaneous nocturnal erections and masturbation in captive male chimpanzees (Pan troglodytes)

チンパンジーにおける夜間勃起現象の発見 --他の目的の研究からの偶然の産物--. 京都大学プレスリリース. 2022-05-13.Chimps, dreams, and videotape. 京都大学プレスリリース. 2022-05-13.Nocturnal penile tumescence (NPT) has been reported for males of only a few mammalian species, including humans, albeit this scarcity might be an artefact of the difficulty of documenting it. We investigated NPT in 12 adult male chimpanzees living in an all-male group at Kumamoto Sanctuary, Japan. Recorded non-invasively with infrared video cameras across 72 nights (6 per individual), we observed NPT in two thirds of the individuals (8/12), with N=46 events in total. More than three quarters occurred during a transition from sleep to wakefulness, suggesting NPT may be associated with rapid eye movement sleep, similar to humans. Masturbation occurred in conjunction with NPT, including the likely consumption of ejaculate, in 4–6 individuals. While detailing nocturnal erections in chimpanzees may help us to better understand this robust physiological phenomenon in humans, further comparative research is necessary to reconstruct its phylogenetic history. At present, our findings support hypothetical functional explanations such as the facilitation of nocturnal emissions in order to increase ejaculate quality or an increase in tissue oxygenation to prevent erectile dysfunction.夜間陰茎勃起はヒトの男性において広く一般に生じる現象であるが、ヒト以外の動物での報告は少ない。これは、夜間の観察が難しいことによるものと考えられる。本研究では、京都大学熊本サンクチュアリにおいて12個体の男性チンパンジーの夜間の様子を赤外線カメラによって撮影し、各個体につき6夜間分の行動の記録と分析をおこなった。その結果、12個体のうち8個体で、のべ23夜間において46事例の夜間陰茎勃起が観察された。この46事例のうち11事例ではマスターベーションを伴って観察された。また、全事例のうち約80％が睡眠から覚醒する過程において生じており、ヒトと同様にチンパンジーでもレム睡眠の期間中もしくはその後に生じる現象であることが示唆される。夜間陰茎勃起のあとにマスターベーションをおこなったのは4－6個体だった。マスターベーションのあとに手を口に運ぶ動作が確認されており、精液を食べたと推測される。チンパンジーの夜間勃起現象の詳細な記述により、ヒトにおける本現象についての理解が深まると期待できるが、系統的基盤を明らかにするためには今後さらなる比較研究が必要である。我々の観察は、夜間勃起現象の機能として、射精を促し古い精子を排出して新しい精子に入れ替える効果や、組織への酸素供給の効果があるとする仮説を支持するものである

The Seasonality Thermostat: Female Reproductive Synchrony and Male Behavior in Monkeys, Neanderthals, and Modern Humans

Reproductive synchrony or desynchrony of primate females influences number and fitness of males in mating systems. Langur monkey populations provide a natural ex periment for observing alternative female strategies of confusing or concentrating paternity. Where females escape seasonal reproductive constraints, they desynchro - nize fertility and show visible cues (menstruation), enabling single males to monopolize matings. This increases female fitness by reducing food competition. Where langurs are seasonally constrained, females conceal fertility, confusing paternity and reducing infanticide. These case studies illuminate how hominin females could increase male numbers and investment. Fitness payoffs to male investors will be affected by degree of reproductive sea - sonal constraint, and by females either concealing or confusing menstrual cues of imminent fertility. Among ancestors of modern humans and Neanderthals these strategies diverged. Under pressure of encephalization, modern human female ancestors, less seasonally constrained, pursued a strategy of cosmeticization of menstrual signals. This Female Cosmetic Coalitions model accounts for the African Middle Stone Age record of pigment use. Among Neanderthals, strategies alternated. Severe seasonality during glacial cycles tied Neanderthal males into pair-bonds, suppressing cosmetic signaling. Only during interglacials when seasonality relaxed would Neander - thal females require blood-red cosmetics. Our Seasonality Thermostat model explains why European ochre use correlates with climate through the Middle to Late Pleistocene

The evolution of masturbation is associated with postcopulatory selection and pathogen avoidance in primates

Masturbation occurs throughout the animal kingdom. At first glance, however, the fitness benefits of this self-directed behaviour are unclear. Regardless, several drivers have been proposed. Non-functional hypotheses posit that masturbation is either a pathology, or a byproduct of high underlying sexual arousal, whereas functional hypotheses argue an adaptive benefit. The Postcopulatory Selection Hypothesis states that masturbation aids the chances of fertilization, while the Pathogen Avoidance Hypothesis states that masturbation helps reduce host infection by flushing pathogens from the genital tract. Here, we present comprehensive new data documenting masturbation across the primate order and use these, in conjunction with phylogenetic comparative methods, to reconstruct the evolutionary pathways and correlates of masturbation. We find that masturbation is an ancient trait within the primate order, becoming a more common aspect of the haplorrhine behavioural repertoire after the split from tarsiers. Our analyses provide support for both the Postcopulatory Selection and Pathogen Avoidance Hypotheses in male primates, suggesting that masturbation may be an adaptive trait, functioning at a macroevolutionary scale

Prospective Multicenter Randomized Phase III Study of Weekly versus Standard Docetaxel (D2) for First-Line Treatment of Metastatic Breast Cancer

Purpose: Previous phase II studies have indicated a greatly reduced hematotoxicity of docetaxel-based regimens administered on weekly schedules. The present trial was initiated to randomly compare the toxicity and efficacy of weekly docetaxel versus its standard 3-weekly application. Methods: Patients previously untreated with chemotherapy for metastatic disease were recruited. Patients aged >60 years or with a Karnofsky Perfomance Status (KPS) of 60-80% were eligible for the D2 study. Patients were randomized to receive docetaxel either on a 3-weekly {[}75 mg/m(2) every 3 weeks (q3w)] or on a weekly (30 mg/m(2) on days 1, 8, and 15; q4w) schedule. Treatment was continued until a maximum of 8 cycles, unacceptable toxicity, or disease progression. All patients received standard corticosteroid prophylaxis. Results: Since statistical significance for the primary endpoint (toxicity) was achieved in the interim analysis, the study was closed according to the study protocol (102 of 162 patients). Compared to the standard arm, leukopenia >= grade 3 was a rare event in the weekly arm of the D2 study (per-patient analysis: 4.2% q1w vs. 51.9% q3w; p < 0.0001). No difference was observed between the 2 schedules regarding the occurrence of anemia or thrombocytopenia. With regard to non-hematological toxicity, there was a higher incidence of skin/nail and hepatological toxicity with the weekly schedule, whereas neurotoxicity was observed more often in the standard arm. The rate of omitted doses was significantly increased in the weekly arm (8.6% q1w vs. 0% q3w). The overall response rate was 22.9% in the weekly arm compared to 42.6% in the standard arm (p = 0.039). Time to progression was 5.4 (q1w) versus 6.3 (q3w) months (p = 0.91), and overall survival was 22.7 (q1w) versus 15.8 (q3w) months (p = 0.24). Conclusion: The present data support the feasibility of both weekly and 3-weekly application of docetaxel. As expected, severe leukopenia seems avoidable in weekly scheduled single-agent docetaxel and may serve as an important treatment option, particularly in elderly patients and patients with a reduced performance status. Copyright (C) 2011 S. Karger AG, Base

Prospective Multicenter Randomized Phase III Study of Weekly versus Standard Docetaxel plus Doxorubicin (D4) for First-Line Treatment of Metastatic Breast Cancer

Purpose: Previous phase II studies have indicated a greatly reduced hematotoxicity of docetaxel-based regimens administered on weekly schedules. The present trial was initiated to compare the toxicity and efficacy of weekly docetaxel versus its standard 3-weekly application in combination with doxorubicin. Methods: Patients previously untreated with chemotherapy for metastatic disease were recruited. Inclusion criteria were age = grade 3 was observed in the standard arm of the D4 study compared to the weekly schedule (per-patient analysis: 61.9% q3w vs. 65.1% q1w; p > 0.05). Grade 3 and grade 4 fever, diarrhea, and infections occurred more frequently in the standard arm, whereas neurotoxicity and skin/nail disorders were observed more frequently in the weekly arm. Except for fever, none of these differences reached a level of significance. Dose delays, dose reductions, and the rate of omitted doses were increased in the weekly arm. The overall response rate was 44.2% in the weekly arm compared to 52.4% in the standard arm (p = 0.52). Time to progression was 6.2 (q1w) versus 10.3 (q3w) months (p = 0.36), and overall survival was 20.5 (q1w) versus 28.7 (q3w) months (p = 0.98). Conclusion: The present data support the feasibility of both weekly and 3-weekly application of docetaxel in combination with doxorubicin. Nevertheless, given that leukopenia was similar in both arms and the efficacy parameters were at least numerically inferior with the weekly schedule, standard 3-weekly application seems to be preferable for patients requiring combination chemotherapy. Copyright (C) 2011 S. Karger AG, Base