Manipulation of Multi-Photon-Entanglement : Applications in Quantum Information Processing

Over the last twenty years the field of quantum information processing (QIP) has attracted the attention of many scientists, due to the promise of impressive improvements in the areas of computational speed, communication security and the ability to simulate nature on the micro scale. This thesis describes an experimental work on the physics of multi-photon entanglement and its application in the field of QIP. We have thoroughly developed the necessary techniques to generate multipartite entanglement between up to six photons. By exploiting the developed six-photon interferometer, in this thesis we report for the first time the experimental quantum teleportation of a two-qubit composite system, the realization of multi-stage entanglement swapping, the implementation of a teleportation-based controlled-NOT gate for fault-tolerant quantum computation, the first generation of entanglement in sixpartite photonic graph states and the realization of ‘one-way’ quantum computation with two-photon four-qubit cluster states. The methods developed in these experiments are of great significance both for exploring the field of QIP and for future experiments on the fundamental tests of quantum mechanics

Activity-Based Anorexia Reduces Body Weight without Inducing a Separate Food Intake Microstructure or Activity Phenotype in Female Rats—Mediation via an Activation of Distinct Brain Nuclei

Anorexia nervosa (AN) is accompanied by severe somatic and psychosocial complications. However, the underlying pathogenesis is poorly understood, treatment is challenging and often hampered by high relapse. Therefore, more basic research is needed to better understand the disease. Since hyperactivity often plays a role in AN, we characterized an animal model to mimic AN using restricted feeding and hyperactivity. Female Sprague-Dawley rats were divided into four groups: no activity/ad libitum feeding (ad libitum, AL, n=9), activity/ad libitum feeding (activity, AC, n=9), no activity/restricted feeding (RF, n=12) and activity/restricted feeding (activity-based anorexia, ABA, n=11). During the first week all rats were fed ad libitum, ABA and AC had access to a running wheel for 24h/d. From week two ABA and RF only had access to food from 9:00-10:30 am. Body weight was assessed daily, activity and food intake monitored electronically, brain activation assessed using Fos immunohistochemistry at the end of the experiment. While during the first week no body weight differences were observed (p>0.05), after food restriction RF rats showed a body weight decrease: -13% vs. day eight (p0.05). Similarly, the daily physical activity was not different between AC and ABA (p>0.05). The investigation of Fos expression in the brain showed neuronal activation in several brain nuclei such as the supraoptic nucleus, arcuate nucleus, locus coeruleus and nucleus of the solitary tract of ABA compared to AL rats. In conclusion, ABA combining physical activity and restricted feeding likely represents a suited animal model for AN to study pathophysiological alterations and pharmacological treatment options. Nonetheless, cautious interpretation of the data is necessary since rats do not voluntarily reduce their body weight as observed in human AN

Soil wettability can be explained by the chemical composition of particle interfaces-An XPS study

Soil wettability (quantified in terms of contact angle, CA) is crucial for physical, chemical, and biological soil functioning. As the CA is determined by components present within the outmost nanometer of particles, this study applied X-ray photoelectron spectroscopy (XPS) with a maximum analysis depth of 10 nm to test the relationship between CA and surface elemental composition, using soil samples from a chronosequence where CA increased from 0° (0 yrs) to about 98° (120 yrs). Concurrently, as seen by XPS, C and N content increased and the content of O and the mineral-derived cations (Si, Al, K, Na, Ca, Mg, Fe) decreased. The C content was positively correlated with CA and least squares fitting indicated increasing amounts of non-polar C species with soil age. The contents of O and the mineral-derived cations were negatively correlated with CA, suggesting an increasing organic coating of the minerals that progressively masked the underlying mineral phase. The atomic O/C ratio was found to show a close negative relationship with CA, which applied as well to further sample sets of different texture and origin. This suggests the surface O/C ratio to be a general parameter linking surface wettability and surface elemental composition.DFG/SPP/1315DFG/BA 1359/9DFG/FOR/180

Causal and mediating factors for anxiety, depression and well-being

Background The relationship between well-being and mental ill health is complex; people may experience very low levels of well-being even in the absence of overt mental health problems. Aims This study tested the hypothesis that anxiety, depression and well-being have different causal determinants and psychological mediating mechanisms. Method The influence of causal and mediating factors on anxiety, depression and well-being were investigated in a cross-sectional online questionnaire survey hosted on a UK national broadcasting website. Results Multivariate conditional independence analysis of data from 27 397 participants revealed different association pathways for the two constructs. Anxiety and depression were associated with negative life events mediated by rumination; low levels of subjective well-being were associated with material deprivation and social isolation, mediated by adaptive coping style. Conclusions Our findings support the 'two continua' model of the relationship between psychological well-being and mental health problems, with implications for both treatment and prevention

The anomalous threshold, confinement, and an essential singularity in the heavy-light form factor

The analytic behavior of the heavy-light meson form factor is investigated using several relativistic examples including unconfined, weakly confined, and strongly confined mesons. It is observed that confinement erases the anomalous threshold singularity and also induces an essential singularity at the normal annihilation threshold. In the weak confinement limit, the "would be" anomalous threshold contribution is identical to that of the real singularity on its space-like side.Comment: Latex 2.09 with epsf.sty. 24 pages of text and 8 postscript figures. Postscript version of complete paper will also be available soon at http://phenom.physics.wisc.edu/pub/preprints/1997/madph-97-983 or at ftp://phenom.physics.wisc.edu/pub/preprints/1997/madph-97-98

Nesfatin-130−59 Injected Intracerebroventricularly Differentially Affects Food Intake Microstructure in Rats Under Normal Weight and Diet-Induced Obese Conditions

Nesfatin-1 is well-established to induce an anorexigenic effect. Recently, nesfatin-130−59, was identified as active core of full length nesfatin-11−82 in mice, while its role in rats remains unclear. Therefore, we investigated the effects of nesfatin-130−59 injected intracerebroventricularly (icv) on the food intake microstructure in rats. To assess whether the effect was also mediated peripherally we injected nesfatin-130−59 intraperitoneally (ip). Since obesity affects the signaling of various food intake-regulatory peptides we investigated the effects of nesfatin-130−59 under conditions of diet- induced obesity (DIO). Male Sprague–Dawley rats fed ad libitum with standard diet were icv cannulated and injected with vehicle (5 μl ddH2O) or nesfatin-130−59 at 0.37, 1.1, and 3.3 μg (0.1, 0.3, 0.9 nmol/rat) and the food intake microstructure assessed using a food intake monitoring system. Next, naïve rats were injected ip with vehicle (300 μl saline) or nesfatin-130−59 (8.1, 24.3, 72.9 nmol/kg). Lastly, rats were fed a high fat diet for 10 weeks and those developing DIO were icv cannulated. Nesfatin-1 (0.9 nmol/rat) or vehicle (5 μl ddH2O) was injected icv and the food intake microstructure assessed. In rats fed standard diet, nesfatin-130−59 caused a dose-dependent reduction of dark phase food intake reaching significance at 0.9 nmol/rat in the period of 4–8 h post injection (−29%) with the strongest reduction during the fifth hour (−75%), an effect detectable for 24 h (−12%, p < 0.05 vs. vehicle). The anorexigenic effect of nesfatin-130−59 was due to a reduction in meal size (−44%, p < 0.05), while meal frequency was not altered compared to vehicle. In contrast to icv injection, nesfatin-130−59 injected ip in up to 30-fold higher doses did not alter food intake. In DIO rats fed high fat diet, nesfatin-130−59 injected icv reduced food intake in the third hour post injection (−71%), an effect due to a reduced meal frequency (−27%, p < 0.05), while meal size was not altered. Taken together, nesfatin-130−59 is the active core of nesfatin-11−82 and acts centrally to reduce food intake in rats. The anorexigenic effect depends on the metabolic condition with increased satiation (reduction in meal size) under normal weight conditions, while in DIO rats satiety (reduction in meal frequency) is induced

Hypertonic stress induced changes of Pseudomonas fluorescens adhesion towards soil minerals studied by AFM

Studying bacterial adhesion to mineral surfaces is crucial for understanding soil properties. Recent research suggests that minimal coverage of sand particles with cell fragments significantly reduces soil wettability. Using atomic force microscopy (AFM), we investigated the influence of hypertonic stress on Pseudomonas fluorescens adhesion to four different minerals in water. These findings were compared with theoretical XDLVO predictions. To make adhesion force measurements comparable for irregularly shaped particles, we normalized adhesion forces by the respective cell-mineral contact area. Our study revealed an inverse relationship between wettability and the surface-organic carbon content of the minerals. This relationship was evident in the increased adhesion of cells to minerals with decreasing wettability. This phenomenon was attributed to hydrophobic interactions, which appeared to be predominant in all cell–mineral interaction scenarios alongside with hydrogen bonding. Moreover, while montmorillonite and goethite exhibited stronger adhesion to stressed cells, presumably due to enhanced hydrophobic interactions, kaolinite showed an unexpected trend of weaker adhesion to stressed cells. Surprisingly, the adhesion of quartz remained independent of cell stress level. Discrepancies between measured cell–mineral interactions and those calculated by XDLVO, assuming an idealized sphere-plane geometry, helped us interpret the chemical heterogeneity arising from differently exposed edges and planes of minerals. Our results suggest that bacteria may have a significant impact on soil wettability under changing moisture condition

Performance- and Stimulus-Dependent Oscillations in Monkey Prefrontal Cortex During Short-Term Memory

Short-term memory requires the coordination of sub-processes like encoding, retention, retrieval and comparison of stored material to subsequent input. Neuronal oscillations have an inherent time structure, can effectively coordinate synaptic integration of large neuron populations and could therefore organize and integrate distributed sub-processes in time and space. We observed field potential oscillations (14–95 Hz) in ventral prefrontal cortex of monkeys performing a visual memory task. Stimulus-selective and performance-dependent oscillations occurred simultaneously at 65–95 Hz and 14–50 Hz, the latter being phase-locked throughout memory maintenance. We propose that prefrontal oscillatory activity may be instrumental for the dynamical integration of local and global neuronal processes underlying short-term memory

Nesfatin-1(30-59) injected intracerebroventricularly increases anxiety, depression-like behavior, and anhedonia in normal weight rats

Nesfatin-1 is a well-established anorexigenic peptide. Recent studies indicated an association between nesfatin-1 and anxiety/depression-like behavior. However, it is unclear whether this effect is retained in obesity. The aim was to investigate the effect of nesfatin-1(30-59)—the active core of nesfatin-1—on anxiety and depression-like behavior in normal weight (NW) and diet-induced (DIO) obese rats. Male rats were intracerebroventricularly (ICV) cannulated and received nesfatin-1(30-59) (0.1, 0.3, or 0.9 nmol/rat) or vehicle 30 min before testing. Nesfatin-1(30-59) at a dose of 0.3 nmol reduced sucrose consumption in the sucrose preference test in NW rats compared to vehicle (-33%, p 0.05). These results indicate an implication of nesfatin-1(30-59) in the mediation of anxiety and depression-like behavior/anhedonia under normal weight conditions, while in DIO rats, a desensitization might occur