The transverse momentum distribution of hadrons within jets

We study the transverse momentum distribution of hadrons within jets, where the transverse momentum is defined with respect to the standard jet axis. We consider the case where the jet substructure measurement is performed for an inclusive jet sample $pp\to\text{jet}+X$. We demonstrate that this observable provides new opportunities to study transverse momentum dependent fragmentation functions (TMDFFs) which are currently poorly constrained from data, especially for gluons. The factorization of the cross section is obtained within Soft Collinear Effective Theory (SCET), and we show that the relevant TMDFFs are the same as for the more traditional processes semi-inclusive deep inelastic scattering (SIDIS) and electron-positron annihilation. Different than in SIDIS, the observable for the in-jet fragmentation does not depend on TMD parton distribution functions which allows for a cleaner and more direct probe of TMDFFs. We present numerical results and compare to available data from the LHC.Comment: 28 pages, 3 figures, published versio

Fractal Metamaterial Absorber with Three-Order Oblique Cross Dipole Slot Structure and its Application for In-band RCS Reduction of Array Antennas

To miniaturize the perfect metamaterial absorber, a fractal three-order oblique cross dipole slot structure is proposed and investigated in this paper. The fractal perfect metamaterial absorber (FPMA) consists of two metallic layers separated by a lossy dielectric substrate. The top layer etched a three-order oblique fractal-shaped cross dipole slot set in a square patch and the bottom one is a solid metal. The parametric study is performed for providing practical design guidelines. A prototype with a thickness of 0.0106λ (λ is the wavelength at 3.18 GHz) of the FPMA was designed, fabricated, measured, and is loaded on a 1×10 guidewave slot array antennas to reduce the in-band radar cross section (RCS) based on their surface current distribution. Experiments are carried out to verify the simulation results, and the experimental results show that the absorption at normal incidence is above 90% from 3.17 to 3.22GHz, the size for the absorber is 0.1λ×0.1λ, the three-order FPMA is miniaturized 60% compared with the zero-order ones, and the array antennas significantly obtain the RCS reduction without the radiation deterioration

Modelling weed management effects on soil erosion in rubber plantations in Southwest China

Land use in Xishuangbanna, Southwest China, a typical subtropical rain forest region, has been dramatically changed over the past 30 years. Driven by favorable market opportunities, a rapid expansion of rubber plantations has taken place. This disturbs forests and land occupied by traditional swidden agriculture thus strongly affecting hydrological/erosion processes, and threatening soil fertility and water quality. The presented PhD thesis aimed at assessing farmer acceptable soil conservation strategies in rubber plantations that efficiently control on-site soil loss over an entire rotation time (25 40 years) and off-site sediment yield in the watershed. The study started with field investigations on erosion processes and soil conservation management options in rubber plantations (Chapter 2 and 3). Based on the field data, the physically based model Land Use Change Impact Assessment (LUCIA) was employed to assess long-term conservation effects in rubber plantations (Chapter 4) and scale effects on sediment yield in the watershed (Chapter 5). Specifically, the first study aimed at assessing soil loss in rubber plantations of different ages (4, 12, 18, 25 and 36 year old) and relating erosion potential to surface cover and fine root density by applying the Universal Soil Loss Equation (USLE) model. This study adopted the space-for-time substitution for field experimental design instead of establishing a long-term observation. Spatial heterogeneity of soil properties (e.g. texture, organic carbon content) and topography (slope steepness and length) interfered erosion at different plantation ages. To meet this challenge, namely account for possible impacts of soil properties and slope on erosion, the empirical USLE model was applied in data analysis to calculate the combined annual cover, management and support practice factor CP, which represents ecosystem erosivity. Calculated CP values varied with the growth phase of rubber in the range of 0.006 - 0.03. Surface cover was recognized as the major driver responsible for the erosive potential changes in rubber plantations. The mid-age rubber plantation exhibited the largest erosion (3 Mg ha-1) due to relatively low surface cover (40%-60%) during the rainy season, which was attributed to low weed cover (below 20%) and the low surface-litter cover favored by a high decomposition rate. Based on the results of the first study, the second study focused on reducing soil loss in rubber plantations by maintaining a high surface cover through improved weed management. Among the different weeding strategies tested, no-weeding most efficiently reduced on-site soil loss to 0.5 Mg ha-1. However, due to the low farmer acceptance of the no-weeding option, we recommend reducing herbicide application to a single dose at the beginning of the rainy season (once-weeding) to better conserve soil as well as inhibiting overgrowth of the understory vegetation. As the second experiment lasted only one-year, while rubber plantation is a perennial crop with a commercial lifespan of 25 40 years, the third study applied the LUCIA model to simulate the temporal dynamics of soil erosion in rubber plantations under different weeding strategies. The erosion module in LUCIA was extended to simulate both runoff and rainfall based soil detachment to better reflect the impact of the multi-layer structure of the plantation canopy. The improved LUCIA model successfully represented weed management effects on soil loss and runoff at the test site with a modelling efficiency (EF) of 0.5-0.96 and R2 of 0.64-0.92. Long-term simulation results confirmed that once-weeding controlled annual soil loss below 1 Mg ha-1 and kept weed cover below 50%. Therefore, this weeding strategy was suggested as an eco- and farmer friendly management in rubber plantations. Furthermore, LUCIA was applied at watershed level to evaluate plot conservation impact on sediment yield. Two neighboring sub-watersheds with different land cover were chosen: one a forest dominated (S1, control), the other with a mosaic land use (S2), which served to assess mono-conservation (conservation only in rubber plantations) and multi-conservation (conservation in maize, rubber and tea plantations) effects on total sediment yields. The model was well calibrated and validated based on peak flow (EF of 0.70 for calibration and 0.83 for validation) and sediment yield (EF of 0.71 for calibration and 0.95 for validation) measured from the two watersheds outlet points. Model results showed that improved weed management in rubber plantations can efficiently reduce the total sediment yields by 20%; while multi-conservation was largely able to offset increased sediment yields by land use change. In summary, while exploring the dynamics of erosion processes in rubber plantations, a physically based model (LUCIA) was extended and applied to simulate weed management effects over an entire crop cycle (40 years) and implications at higher scale level (watershed sediment yield). Once-weeding per year was identified as an improved management to reduce on-site erosion and off-site sediment yield. But to fully offset increased sediment yield by land use change, a multi-conservation strategy should be employed, which not only focuses on new land uses, like rubber plantations, but also takes care of traditional agricultural types. A conceptual framework is proposed to further assess the specific sub-watershed erosion (e.g. sediment or water yield) effects in large watersheds by spatially combining process-oriented and data-driven (e.g. statistic based, machine learning based) models. This study also serves as a case study to investigate ecological issues (e.g. erosion processes, land use change impact) based on short-term data and modelling in the absence of long-term observations.Die Landnutzung in Xishuangbanna, Südwestchina, einer typischen subtropischen Regenwaldregion, hat sich in den letzten 30 Jahren dramatisch verändert. Getrieben von günstigen Marktchancen hat ein rapider Ausbau von Kautschukplantagen stattgefunden. Dies beeinflusst Wälder und Flächen, die durch traditionellem Brandrodungsackerbau bewirtschaftet werden, was starke Auswirkungen auf hydrologische Prozesse und Erosionsprozesse hat und die Bodenfruchtbarkeit und Wasserqualität bedroht. Die vorliegende Dissertation zielte auf die Bewertung von akzeptablen Bodenschutzstrategien für Landwirte in Kautschukplantagen ab, die den Bodenverlust innerhalb des Standortes während einer ganzen Rotationszeit (25 - 40 Jahre) und den Sedimentausstoß außerhalb des Standortes im Wassereinzugsgebiet effizient kontrollieren. Die Studie begann mit Felduntersuchungen zu Erosionsprozessen und Bodenschutz-Managementoptionen in Kautschukplantagen (Kapitel 2 und 3). Basierend auf den Felddaten wurde das physikalisch basierte Modell "Land Use Change Impact Assessment" (LUCIA) eingesetzt, um Langzeitschutzeffekte in Kautschukplantagen (Kapitel 4) und Skaleffekte auf den Sedimentausstoß im Wassereinzugsgebiet zu bewerten (Kapitel 5). Konkret zielte die erste Studie darauf ab, den Bodenverlust in Kautschukplantagen unterschiedlichen Alters (4, 12, 18, 25 und 36 Jahre alt) zu untersuchen und das Erosionspotenzial mit der Allgemeinen Bodenabtragsgleichung (USLE) in Beziehung zur Oberflächenbedeckung und Feinwurzeldichte zu setzen. In dieser Studie wurde die space-for-time substitution für experimentelle Feldforschung anstelle einer Langzeitbeobachtung übernommen. Räumliche Heterogenität der Bodeneigenschaften (z. B. Textur, organischer Kohlenstoffgehalt) und Topographie (Neigungssteilheit und -länge) beeinträchtigten die Erosion bei verschiedenen Pflanzungsaltern. Um dieser Herausforderung zu begegnen, nämlich mögliche Auswirkungen von Bodeneigenschaften und Gefälle auf die Erosion zu berücksichtigen, wurde das empirische USLE-Modell in der Datenanalyse, zur Berechnung der kombinierten jährlichen Bodenbedeckung, Management und support practice factor (CP), das die Ökosystem-Erosivität darstellt, verwendet. Berechnete CP-Werte variierten mit der Wachstumsphase von Kautschuk im Bereich von 0,006-0,03. Die Oberflächenbedeckung wurde als der Haupttreiber für Änderungen des erosiven Potentials in Kautschukplantagen anerkannt. Die Kautschukplantage mittleren Alters wies aufgrund der relativ geringen Oberflächenbedeckung (40% -60%) während der Regenzeit die größte Erosion (3 Mg ha-1) auf. Dies wurde auf einen geringen Unkrautbewuchs (unter 20%) und eine geringe Bodenbedeckung durch Oberflächenstreu, verursacht durch eine hohe Zersetzungsrate, zurückgeführt. Basierend auf den Ergebnissen der ersten Studie konzentrierte sich die zweite Studie auf die Verringerung des Bodenverlusts in Kautschukplantagen, indem eine hohe Oberflächenbedeckung durch verbessertes Unkrautmanagement aufrechterhalten wurde. Unter den verschiedenen getesteten Unkrautbekämpfungsstrategien reduzierte no-weeding den Bodenverlust vor Ort auf 0,5 Mg ha-1 am effizientesten. Aufgrund der geringen Akzeptanz der Unkrautbekämpfung durch den Landwirt empfehlen wir jedoch zu Beginn der Regenzeit (einmaliges Unkrautjäten) eine Herbizidapplikation auf eine Einzeldosis zu reduzieren, um den Boden besser zu erhalten und das Überwachsen der Unterholzvegetation zu verhindern. Da das zweite Experiment nur ein Jahr dauerte, während die Kautschukplantage eine mehrjährige Pflanze mit einer kommerziellen Lebensdauer von 25 bis 40 Jahren ist, wurde in der dritten Studie das LUCIA-Modell zur Simulation der zeitlichen Dynamik der Bodenerosion in Kautschukplantagen unter verschiedenen Strategien eingesetzt. Das Erosionsmodul in LUCIA wurde erweitert, um sowohl oberflächenabfluss- als auch niederschlagsbedingte Bodenerosion zu simulieren, um den Einfluss der mehrschichtigen Struktur des Plantagenschirms besser widerzuspiegeln. Das verbesserte LUCIA-Modell stellte erfolgreich die Auswirkungen des Unkrautmanagements auf den Bodenverlust und den Oberflächenabfluss am Versuchsstandort mit einer Modellierungseffizienz (EF) von 0,5-0,96 und R2 von 0,64-0,92 dar. Die Ergebnisse der Langzeitsimulationen bestätigten, dass "einmaliges Jäten" den jährlichen Bodenverlust unter 1 Mg ha-1 kontrollierte und die Unkrautabdeckung unter 50% hielt. Daher wurde diese Unkrautbekämpfungsstrategie als umwelt- und landwirtfreundliches Management in Kautschukplantagen vorgeschlagen. Darüber hinaus wurde LUCIA auf Wassereinzugsgebietsebene angewendet, um die Auswirkung der Flächenerhaltung auf den Sedimentausstoß zu bewerten. Zur Bewertung der Auswirkungen auf die Gesamtsedimentmengen wurden zwei benachbarte Teileinzugsgebiete mit unterschiedlicher Landbedeckung ausgewählt. Für die Auswirkungen von Einzelschutz (mono-conservation; Schutz nur in Kautschukplantagen) hat eine von Wald dominierende Landnutzung (S1, Kontrolle) gedient und für die Auswirkungen von Mehrfachschutz (multi-conservation; Schutz in Mais-, Kautschuk- und Teeplantagen) eine Mosaiklandnutzung (S2). Das Modell wurde gut kalibriert und validiert basierend auf dem Peak-Flow (EF von 0,70 für die Kalibrierung und 0,83 für die Validierung) und dem Sedimentertrag (EF von 0,71 für die Kalibrierung und 0,95 für die Validierung), die an den zwei Austrittsstellen des Wassereinzugsgebiets gemessen wurden. Die Modellergebnisse zeigten, dass ein verbessertes Unkrautmanagement in Kautschukplantagen die gesamten Sedimentausbeuten um 20% reduzieren kann; während Mehrfachschutz weitgehend in der Lage war, erhöhte Sedimenterträge durch Landnutzungsänderungen auszugleichen. Zusammenfassend wurde, während der Untersuchung der Dynamik von Erosionsprozessen in Kautschukplantagen, ein physikalisch basiertes Modell (LUCIA) erweitert und angewendet, um Unkrautmanagementeffekte über einen gesamten Erntezyklus (40 Jahre) und Implikationen auf höherer Maßstabsebene (Wasserscheidensedimentmenge) zu simulieren. Einmaliges Unkrautbekämpfung pro Jahr wurde als verbessertes Management identifiziert, um die Erosion vor Ort und den Sedimentaustrag außerhalb des Wassereinzugsgebietes zu reduzieren. Um den durch die Landnutzungsänderung erhöhten Sedimentausstoß jedoch vollständig ausgleichen zu können, sollte eine Mehrfachschutzstrategie angewandt werden, die sich nicht nur auf neue Landnutzungen wie Kautschukplantagen konzentriert, sondern sich auch um traditionelle landwirtschaftliche Typen kümmert. Ein konzeptueller Rahmen wird vorgeschlagen, um die spezifischen Erosionseffekte der sub-Wassereinzugsgebiete (z. B. Sediment oder Wasserausbeute) in großen Wassereinzugsgebieten durch räumliche Kombination von prozessorientierten und datengesteuerten (z. B. statistisch und machine-learning basierten) Modellen weiter zu bewerten. Diese Studie dient auch als Fallstudie zur Untersuchung ökologischer Fragen (z. B. Erosionsprozesse, Auswirkungen von Landnutzungsänderungen) auf der Grundlage von Kurzzeitdaten und Modellierung in Abwesenheit von Langzeitbeobachtungen

An optimized high-performance liquid chromatography (HPLC) method for benzoylmesaconine determination in Radix Aconiti Lateralis Preparata (Fuzi, aconite roots) and its products

<p>Abstract</p> <p>Background</p> <p>Benzoylmesaconine (BMA) is the main <it>Aconitum </it>alkaloid in <it>Radix Aconiti Lateralis Preparata </it>(<it>Fuzi</it>, aconite roots) with potent pharmacological activities, such as analgesia and anti-inflammation. The present study developed a simple and reliable method using BMA as a marker compound for the quality control of processed aconite roots and their products.</p> <p>Methods</p> <p>After extraction, a high-performance liquid chromatography (HPLC) determination of BMA was conducted on a RP-C₁₈column by gradient elution with acetonitrile and aqueous phase, containing 0.1% phosphoric acid adjusted with triethylamine to pH 3.0.</p> <p>Results</p> <p>A distinct peak profile was obtained and separation of BMA was achieved. Method validation showed that the relative standard deviations (RSDs) of the precision of BMA in all intra-day and inter-day assays were less than 1.36%, and that the average recovery rate was 96.95%. Quantitative analysis of BMA showed that the content of BMA varied significantly in processed aconite roots and their products.</p> <p>Conclusion</p> <p>This HPLC method using BMA as a marker compound is applicable to the quality control of processed aconite roots and their products.</p

A High‐resolution Atmospheric Dust Record for 1810–2004 A.D. Derived from an Ice Core in Eastern Tien Shan, Central Asia

Centennial‐scale, high‐resolution records of atmospheric dust conditions are rare in the arid and semiarid regions of central Asia, limiting our understanding of the regional climate and environmental changes and their potential driving forces. In this paper, we present an annually resolved atmospheric dust record covering the period of 1810–2004 A.D., reconstructed from an ice core retrieved at 4512 m above sea level from the Miaoergou Glacier in the eastern Tien Shan. The time series of dust flux for the past 195 years shows three periods of relatively low values (i.e., 1810–1829 A.D., 1863–1940 A.D., and 1979–2004 A.D.) and two periods of relatively high values (i.e., 1830–1862 A.D. and 1941–1978 A.D.). Spatial correlation analysis suggests possible regional factors controlling the dust flux, including antecedent summer precipitation, spring soil moisture, and near‐surface wind speed. In addition, the Miaoergou dust flux is closely associated with the winter index of the North Atlantic Oscillation (NAO) over the past two centuries, with high (low) dust periods coinciding with the negative (positive) phases of the NAO. The persistent relationship suggests that the NAO may have been a key driver on dust flux change over the arid regions between the Tien Shan and Kunlun Mountains

Possible Recent Warming Hiatus on the Northwestern Tibetan Plateau Derived from Ice Core Records

Many studies have reported enhanced warming trend on the Tibetan Plateau (TP), even during the warming hiatus period. However, most of these studies are based on instrumental data largely collected from the eastern TP, whereas the temperature trend over the extensive northwestern TP remains uncertain due to few meteorological stations. Here we combined the stable isotopic δ18O record of an ice core recovered in 2012 from the Chongce glacier with the δ18O records of two other ice cores (i.e., Muztagata and Zangser Kangri) in the same region to establish a regional temperature series for the northwestern TP. The reconstruction shows a significant warming trend with a rate of 0.74 ± 0.12 °C/decade for the period 1970–2000, but a decreasing trend from 2001 to 2012. This is consistent with the reduction of warming rates during the recent decade observed at the only two meteorological stations on the northwestern TP, even though most stations on the eastern TP have shown persistent warming during the same period. Our results suggest a possible recent warming hiatus on the northwestern TP. This could have contributed to the relatively stable status of glaciers in this region

High-detectivity ultraviolet photodetectors based on laterally mesoporous GaN

Photodetectors for the ultraviolet (UV) range of the electromagnetic spectrum are in great demand for several technologies, but require the development of novel device structures and materials. Here we report on the high detectivity of UV photodetectors based on well-ordered laterally mesoporous GaN. The specific detectivity of our devices under UV-illumination reaches values of up to 5.3×1014 Jones. We attribute this high specific detectivity to the properties of the mesoporous GaN/metal contact interface: the trapping of photo-generated holes at the interface lowers the Schottky barrier height thus causing a large internal gain. The high detectivity along with the simple fabrication process make these laterally mesoporous GaN photodetectors of great potential for applications that require selective detection of weak optical signals in the UV range

Exploring Light-Cone Distribution Amplitudes from Quantum Computing

Light-cone distribution amplitudes (LCDAs) are essential nonperturbative quantities for theoretical predictions of exclusive high-energy processes in quantum chromodynamics (QCD). We demonstrate the prospect of calculating LCDAs on a quantum computer by applying a recently proposed quantum algorithm, with staggered fermions, to the simulation of the LCDA in the (1+1)-dimensional Nambu-Jona-Lasinio (NJL) model on classical hardware. The agreement between the result from the classical simulation of the quantum algorithm and that from exact diagonalization justifies the proposed quantum algorithm. We find that the resulting LCDA in the NJL model exhibits features shared with the LCDAs obtained from QCD.Comment: 8 pages, 7 figures, published version in Sci.China Phys.Mech.Astro