177 research outputs found
Literatura femenina de viajes en el mundo virtual â enfoques del ecofeminismo y feminismo de la diferencia en blogs de viajes
This paper intends to track the development of traditional feminist ideas through the analysis of three contemporary travel blogs. These traditional feminist concepts are to be seen in the construction of a collective female identity that enables transnational and transgenerational solidarity: by receiving and transmitting inspiration, shelter and encouragement among female travellers, the narrators in the blogs create a system of female authority. Within this system, female role models as well as maternal figures become points of reference that help to revalue female attributes. This concept shows allusions to the theory of difference feminism as it is presented in the «symbolic order of the mother» by Luisa Muraro. A similar approach of revaluating femininity happens through the orientation towards âMother Natureâ. By staging womenâs ability to give birth, cultural ecofeminists like Susan Griffin intend to affirm a close bond between women and nature. This representation of an emphasised femininity becomes a central marker in the narratives of the blogs. While this agenda might be designed to counter gendered spaces and the traditional alienation of women within travel discourse, it is problematised by exclusionary and essentialist definitions of femininity that harden engendered binaries like masculinity/femininity or nature/culture.Este artĂculo examina el desarrollo de ideas feministas tradicionales en blogs contemporĂĄneos de viajes basĂĄndose en tres ejemplos. La estructura narrativa de estos textos expone una identitad colectiva femenina que posibilita la solidaridad trasnacional y transgeneracional: recibiendo y transmitiendo inspiraciĂłn, refugio y estĂmulo entre viajeras, las narradoras generan un sistema de autoridad femenina. En este sistema, figuras maternales o femeninas funcionan como puntos de referencia que sirven para revalorizar atributos femeninos. Este concepto de gĂ©nero alude a la teorĂa del feminismo de la diferencia tal y como se presenta en «el orden simbĂłlico de la madre» de Luisa Muraro. Un enfoque similar de revalorizar la feminidad ocurre con la orientaciĂłn hacia la âMadre Naturalezaâ. Destacando la capacidad femenina de dar a luz, las ecofeministas culturales como Susan Griffin apuntan a establecer un vĂnculo cercano entre mujeres y la naturaleza. Esta representaciĂłn de una feminidad enfatizada es una marca central en las narrativas de los blogs. Mientras esta agenda funciona para contrarrestar la marginaciĂłn tradicional de mujeres en la narrativa de viajes, sus definiciones excluyentes y esencialistas de feminidad resultan problemĂĄticas. Estas comprensiones del gĂ©nero sĂłlo endurecen dualismos como masculinidad/feminidad o naturaleza/cultura
Nitrification suppression and spinach growth in alkaline soil
1976 Spring.Covers not scanned.Includes bibliographical references.A single at-planting application of (NH4)2SO4 with and without nitrapyrin, [2-chloro-6-(trichloromethyl) pyridine], was evaluated on spinach in alkaline soil in 2 field experiments and 1 greenhouse experiment. Parameters measured were soil NH4 -N and NO3 -N, spinach yield, leaf color and leaf P, Fe and Zn. Nitrapyrin was adsorbed onto (NH4)2SO4 crystals then applied in a band at planting in the field experiments. The first field experiment consisted of N application rates of 87. 8 and 157.5 kg/ha and nitrapyrin rates of 0, 280 and 560 g/ha while the second field experiment included N application rates of 0, 45 and 90 kg/ha and nitrapyrin rates of 0, 140, 280 and 420 g/ha. Nitrapyrin (1.5 ppm - dry soil weight basis) was adsorbed onto (NH4)2SO4 crystals and incorporated with soil in the greenhouse at N rates of 0, 400 and 800 mg/2 kg dry soil. Drainage was prevented in this greenhouse experiment. Spinach yields were measured and leaf and soil samples were taken at harvest from the first field experiment and the greenhouse experiment. Yields were measured and leaf and soil samples were taken 28, 42, 48 and 56 days from planting in the second field experiment. Apparently little leaching occurred in the first field experiment and final yield was greatest when N applications included 280 g nitrapyrin/ha. This resulted in high soil concentrations of both NH4 and NO3 at harvest. Concentrated soil NH4 resulting from prolonged nitrification suppression with as much as 560 g nitrapyrin/ha produced good plant growth on this alkaline soil. Leaching had apparently occurred in the second field experiment and increased yields with nitrapyrin 56 days from planting were attributed to increased soil N retention. Prolonged nitrification suppression from 1.5 ppm nitrapyrin in the greenhouse resulted in severely stunted plant growth along with other NH4 toxicity symptoms. Leaf color, which is important in determining market and nutritional quality of spinach, was darker green when (NH4)2SO4 adsorbed with nitrapyrin was applied. This was measured during all 3 experiments. The dark green leaf color was measured and/or observed well before observed yield differences. Leaf P, Fe and Zn concentrations were generally increased when NH4 applications included nitrapyrin in this study. Leaf P concentrations increased the most while leaf Zn concentrations increased the least. Increase in leaf P, Fe and Zn concentrations due to the addition of small amounts of nitrapyrin to NH4 fertilizer may be an important consideration with regard to alkaline soils where P, Fe and Zn are often limiting
Hans Luther, ett hundraÄrsminne
Vol 92 Yearbook 2016.Hans Edmund Luther (July 2, 1915 - June 9, 1982) was Professor in Botany (chair with Swedish as statutory language) at Helsinki University 1961-1978. Hans Luther's main topic was the ecology and distribution of brackish water macrophytes of the Baltic Sea, mainly in the Pojoviken - TvÀrminne area on the southwestern coast of mainland Finland. He studied also algae, e.g. the Xanthophyceae, fungi and terrestrial vascular plants, especially some of polemochorous origin and other ruderals. This paper by two of his pupils describe his career as a scientist and university teacher. Some anecdotes about him are also dealt with. A list of Hans Luther's publications is included.Peer reviewe
Hans Luther, ett hundraÄrsminne
Vol 92 Yearbook 2016.Hans Edmund Luther (July 2, 1915 - June 9, 1982) was Professor in Botany (chair with Swedish as statutory language) at Helsinki University 1961-1978. Hans Luther's main topic was the ecology and distribution of brackish water macrophytes of the Baltic Sea, mainly in the Pojoviken - TvÀrminne area on the southwestern coast of mainland Finland. He studied also algae, e.g. the Xanthophyceae, fungi and terrestrial vascular plants, especially some of polemochorous origin and other ruderals. This paper by two of his pupils describe his career as a scientist and university teacher. Some anecdotes about him are also dealt with. A list of Hans Luther's publications is included.Peer reviewe
Majorana Spin-Flip transition in the ALPHA magnetic trap
The main purpose of the ALPHA collaboration is to trap antihydrogen atoms so that the Charge Conjugation-Parity Transformation-Time Reversal (CPT) symmetry can be tested. The trapping mechanism consists on an octupole magnet that traps the atoms near the magnetic field minima. Once trapped, due to the Majorana spin-flip effect, atoms can escape by changing the orientation of its spin. The magnetic field generated by the octupole magnet present in the trap has multiple zeroes of different orders. These zeroes could affect the probability of a spin flip, and therefore alter the number of escaped atoms. The main problem tackled by the research is how the different zeroes affect the dynamics of the spins, testing if different mathematical descriptions alter significantly the probability of a flip. The utilized method to do this was by computer simulations. First, we developed a program that solved Schrödingerâs equation numerically, with error of quadratic order, for the Hamiltonian of a spin that follows a magnetic field adiabatically. We used this program to simulate the dynamics of the spin in the neighborhood of the magnetic field zeroes using different order approximations for the field. To generate statistical data, we performed a Monte Carlo simulation that generated random directions of approach and impact parameters so that we can construct a cross sections for the spin flip probability. We found that there was no significant difference between the cross section generated by the linear approximation of the field and the third order approximation. Additionally, the decay rates were obtained and the associated lifetimes were big enough so that measurements can be performed in them
Natural succession and human-induced changes in the soft-bottom macrovegetation of shallow brackish bays on the southern coast of Finland
Anatomic Variation of the Knee Extensor Mechanism: The Effect on Tibiofemoral Joint Load and Joint Kinematics
Abstract Background: Variation to extensor mechanism features of patella thickness, patella height, and tuberosity AP (anterior-posterior) and SI (superior-inferior) position will effect knee kinematics and tibiofemoral (TF) joint loads. The variations primarily relate to alterations of the patellar ligament angle, relative to the long axis of the tibia. There are two objectives in this study, first, determine the desired setting of each feature within the analog configuration of the Kansas Knee Simulator (KKS) to better match measured in-vitro TF-AP loads. Second, to describe the correlations between the features, quadriceps load, TF kinematics and patellofemoral (PF) kinematics Methods: To determine the desired analog configuration in the KKS, a custom instrumented tibia tray (ITT) was assembled with total knee replacement components from DePuy Synthes (Attune Primary, Size 8). The ITT measures TF joint load while simulating a dynamic walk and squat motion in the KKS. A design of experiments (DOE) was established, using the Taguchi analysis method to minimize the calculated RMS error. Each feature was varied between three levels. All experiments were conducted in a random order in three separate trials. To determine kinematic correlations between features, a different simulated walk was applied to 18 fresh frozen cadaver knees (age 59.3 ± 13.2 years old, 25.1 ± 6.4 BMI) in the KKS. Data points were taken at every 5% of the cycle for quadriceps load, and TF and PF kinematics. The data were normalized to create an 18x151 correlation matrix for principle component (PC) analysis. Subsequent PCs were included for analysis until 80% total explained variation was reached. The resulting coefficient matrix (âloadingsâ) was used to show the correlation between variables for each PC. Results: Signal-to-noise ratios for each feature were used to set the desired analog configuration at a patella thickness of 28.3-mm, patella height of 44.4-mm, and a tuberosity position of 29.3-mm (SI) and 40.6-mm (AP). The desired configuration reduced the calculated RMS error from 71.95-lbs in the original configuration to 4.76-lbs. The most sensitive factors affecting TF-AP load are patella thickness and tuberosity position. The PC analysis found the first 5 PCs accounted for over 80% of the variation. PC-1 explained 33.4% of the total variation and shows a correlation of patella height to changes in a majority of kinematic descriptions included in this analysis. The remaining PCs showed correlations to specific kinematics and anatomic measures at decreasing amounts of explained variation. Conclusion: Patella thickness and tuberosity position, and the corresponding patella ligament angle, have the greatest effect on TF-AP load. These measures are associated with minimal explained variation and correlated to limited kinematic changes. Patella height had minimal effect on TF-AP load, but is associated with the majority of explained variation and correlated to changes in quadriceps load, tibia rotation, and patella spin, tilt, and ML translation. TF-AP load is most affected by variation in patella thickness and tuberosity position, and kinematic changes are most affected by variation in patella height. Understanding the effects of variation in the three extensor mechanism features will guide more informed conclusions in future research, prosthetic and surgical tool development, and decisions regarding medical intervention
Stress impacts under forestry machinery and consequences on physical soil properties
Auf acht Versuchsstandorten wurden von Oktober 2012 bis April 2014 Ăberfahrungsversuche mit verschiedenen Forst- und Spezialmaschinen (z.âB. John Deere 1270e, Ponsse Buffalo, Rottne F14, EMB Elliator, HĂ€gglunds) in Norddeutschland durchgefĂŒhrt, um die Auswirkun-gen auf bodenphysikalische Parameter und die technische Befahrbarkeit zu quantifizieren. Zur Auswertung der bodenphysikalischen Parameter wurden Lagerungsdichte (ÏB), Vorbelastung (Pv), gesĂ€ttigte WasserleitfĂ€higkeit (kf), LuftleitfĂ€higkeit (kl), Gesamtporenvolumen (GPV) und LuftkapazitĂ€t (LK) fĂŒr jeden Standort und jede Maschinenvariante im Vergleich zu einer unbelasteten Referenz analysiert. Die Untersuchungen erfolgten differenziert fĂŒr die Tiefen 20âcm, 40âcm und 60âcm sowie fĂŒr unterschiedliche BefahrungsintensitĂ€ten (Beprobung z.B. nach der ersten, der fĂŒnften und der zehnten Ăberfahrt). AuĂerdem sind Spannungsmessungen mit dem Stress State Transducer System (SST) in den genannten Tiefen durchgefĂŒhrt worden. Die Auswertung der vertikalen SpannungseintrĂ€ge (Ï1) fĂŒr sich und in Kombination mit Pv geben Auskunft ĂŒber die BodenstabilitĂ€t wĂ€hrend der Befahrung. Somit können zusĂ€tzlich Aussagen zur technischen Befahrbarkeit an jedem Standort gegeben bzw. abgeleitet werden.
Die Ergebnisse zeigen, dass der Einsatz von Holzerntemaschinen (John Deere 1270e) einen erheblichen Einfluss auf die bodenphysikalischen Parameter hat, welcher besonders von den bodenexternen Faktoren Auflast/KontaktflĂ€chendruck und BefahrungsintensitĂ€t abhĂ€ngig ist. Die Auswertung zur BodenstabilitĂ€t (Pv/Ï1) veranschaulicht, dass je schwerer die Maschine und je hĂ€ufiger die Ăberrollung, desto gröĂer und tiefreichender sind die Auswirkungen auf die Bodenstruktur. Die SpannungseintrĂ€ge der Holzerntemaschinen ĂŒbersteigen die Eigensta-bilitĂ€t des Bodens um ein Vielfaches, was bei wiederholter Befahrung in einem Grundbruch resultiert und einen Verlust der technischen Befahrbarkeit nach sich zieht. Als Konsequenz der Befahrung bei besonders feuchten Bedingungen ist eine Homogenisierung der gesamten Bodenstruktur zu beobachten, wie die Versuche mit dem Rottne F14 und die sinkenden Werte von Pv veranschaulichen. Die Spezialmaschine EMB Elliator kann die SpannungseintrĂ€ge bei gleicher Beladung zur Referenzmaschine um bis zu 65â% reduzieren. Die Versuche mit den Spezial-BogiebĂ€ndern zeigen keine positiven Effekte fĂŒr die bodenphysikalischen Parameter. Jedoch kann zumindest die technische Befahrbarkeit fĂŒr die Variante Moorband als sicher eingestuft werden. Die Sicherung der technischen Befahrbarkeit und ein geringer Einfluss auf die Bodenfunktionen werden fĂŒr die Versuche mit den kleineren Maschinen (HĂ€gglunds usw.) beobachtet. Bei den Versuchen zur Wurzelarmierung können keine positiven Effekte des Wurzelgeflechtes zur Spannungsreduktion dokumentiert werden.From October 2012 to April 2014 wheeling experiments with different forestry machinery (harvester: John Deere 1270e (19 Mg); forwarders: Ponsse Buffalo & Rottne F14 (28 Mg); shredder: New Holland FR 9060 (12 Mg); special tracked machines: EMB Elliator (22 Mg); John Deere 6320, HĂ€gglunds and wood trailer (all about 6 Mg)) were done mainly on Haplic Luvisol, Stagnic Luvisol and Haplic Stagnosol derived from loess. The consequences for physical soil functions and trafficability of skid trails were quantified on eight study sites in Northern Germany. Furthermore bogie tracks and the reinforcement of roots were investigat-ed. To evaluate consequences on physical soil functions undisturbed soil samples were ana-lyzed. Bulk density, precompression stress, saturated hydraulic conductivity, air conductivity, total pore volume and air capacity were determined for every single study site in 20âcm, 40âcm and 60âcm depth and were compared with samples after different number of wheeling (for example after first and fifth wheeling) for each tested machine. In addition stress measure-ments with Stress State Transducer System (SST) were carried out in known depth for every machine variant. Evaluation of stress impacts for itself and in combination with precompres-sion stress of soil are indicators for soil stability and allow a statement for trafficability of skid trails.
The results show a considerable impact of forestry machinery on physical soil functions, which is mainly affected by load/ground pressure and number of wheeling. The heavier the machines and the higher the number of wheeling, the higher is the impact on soil functions and the deeper are the consequences on soil structure. The saturated hydraulic conductivity can be characterized as the most sensitive parameter. After first wheeling values of it decrease about 98â% in comparison to an unloaded reference profile. Results for soil stability and de-velopment of stress impacts indicate unstable conditions for every study site. The consequence is a failure of bearing capacity and a loss of trafficability. At wetter conditions a ho-mogenization and a complete destruction of soil structure can be predicted, as tests with Rott-ne F14 confirm. The investigations with special machine EMB Elliator demonstrate, that stress impacts can be reduced about 65â%. Tests with bogie tracks show negative effects for soil functions, but one track (moor-bogie track) is able to reduce stress impacts and to save trafficability. The influence on soil functions of tested smaller machines (John Deere 6320 etc.) is limited to top soil. There are also no negative consequences for trafficability. A rein-forcement of roots and a reduction of stress impacts were not observed, due to the high wheel loads of tested New Holland Fr 9060
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