335 research outputs found
Lifetime of Atomic Spin Chains: Enhancing spin lifetime, remote detection of magnons and implementation of ESR-STM
No full textThis thesis describes atomic spin chains subject to magnetic anisotropy. Such chains, assembled through means of scanning tunneling microscopy (STM), can be home to a plethora of magnetic states and spin physics. This includes quantum tunneling of magnetization, the injection and delocalization of magnons and, for single atoms, the application of electron spin resonance (ESR). Each phenomenon happens at their own timescale which is dependent on the isolation of the spin chain from the environment, ranging from seconds to picoseconds.QN/Otte La
Tergoceracris luquillensis Perez-Gelabert & Otte, 2003, n. sp.
No full textTergoceracris luquillensis n. sp. Figs. 2, 3, 5 F, 6 C, 7, 9, 20, 21 Diagnosis.— Differentiated from the other species as follows: furculae relatively short, not much flared at apex (Fig. 5 F); epiproct lateral ridges unilobed; off center mounds low, poorly developed (Fig. 6 C); tegmina green; lophi of epiphallus very elongate (Fig. 20 D). Description.— Male. Body completely green except for abdominal segments which are greenish brown. Head: Antennae with first 5 segments reddish, the rest brown. Pronotum: dorsally marked by dark annular area surrounded by concentric cream yellow bands. Pronotal side mostly green but with darker black band that does not reach either pronotal margin. Cream yellow band on pronotal side extending over to head. Wings: Tegmina slightly longer than pronotum length and completely green, with surface markedly reticular. Posterior area of wings more acute than in the other species. Abdomen: abdominal segments brown. Vertically elongated furculae smaller than in all other species, narrowing only slightly in the middle, flattening, separating but not widening on upper portion. Internal genitalia as in Figs. 20, 21. Etymology.—Name in aposition, in reference to its type locality. Type material.— Holotype: Male. PUERTO RICO, Luquillo Mts., 3,000 ft., Pico del Oeste, Harvard University Study Site, 26.vi. 1969, T. J. Cohn (ANSP). Allotype: Female. Same data as holotype (ANSP). Paratypes: One adult and four juvenile males, 2 adult females, same data as holotype (ANSP). Two males and 6 females, Sierra de Luquillo, Pico del Oeste, (in Luquillo Experimental Forest), 1150 m, 1718.vii. 1967, R. A. Howard, (UMMZ). One female, onlybearing El Yunque, Puerto Rico as collecting data (NMNH). One female, El Yunque, Caribbean National Forest, 1.4 km on trail to El Toro, on Ocotea leucoxylon (Lauraceae), 26.x. 2001, D. E.PerezGelabert and M. A. García, (DEPG). Habitat.— Wet forest in Sierra de Luquillo, eastern Puerto Rico. Some of the specimens collected by R. A. Howard have notes indicating they were taken on Tabebuia radiata (Bignoniaceae), and were observed tofeed on this plant. The female collected by the senior author in 2001 was found at the edge of the trail at an altitude of 700 800 m on Ocotea leucoxylon (Lauraceae).Published as part of Perez-Gelabert, Daniel E. & Otte, Daniel, 2003, Tergoceracris, a new genus and six new species of montane grasshoppers (Orthoptera: Acrididae: Ommatolampinae) from Dominican Republic and Puerto Rico, pp. 1-31 in Zootaxa 155 on pages 8-9, DOI: 10.5281/zenodo.15697
Tergoceracris guajataca Perez-Gelabert & Otte, 2003, n. sp.
No full textTergoceracris guajataca n. sp. Figs. 3, 5 C, 6 A, 7, 8, 9, 14, 15 Diagnosis.— Similar in coloration and morphology to T. cerropunta and T. cayey while differentiated by the wing color from T. luquillensis. Differs from T. cerropunta and T. cayey as follows: Endophallic plate relatively shorter (about 1.3X as long as ventral valve of aedeagus) (Fig. 15 D); epiproct lateral ridges unilobed and offcenter mounds elongate (Fig. 6 A) (epiproct lateral ridges bilobed in T. cayey and offcenter mounds short in T. cerropunta); lophi of epiphallus more robust in dorsal view (Fig. 14 D). Description.— Male. Coloration very similar to that of T. cerropunta, both brightly adorned. Pronotum: annular area light greenish brown in center surrounded by black and cream yellow bands. Wide band at pronotal side green and light brown, followed below by arched cream yellow band that delimits smaller portion of green on lower margin. Wings: Tegmina short, pink reddish with some black on posterior edge, with surface markedly reticular. Abdomen: dorsal midline marked by interrupted black streak. Furculae vertically elevated, slightly longer and thinner than in the other Puerto Rican species, ascending jointly, narrowing, then separating and widening only slightly on upper portion. Internal genitalia: As illustrated in Figs. 14, 15. Etymology.— The name is derived from the type locality. Type material.— Holotype: Male. PUERTO RICO, Guajataca St. Forest, 7 miles SE Isabela, 600 ft. (200 m), 20.vi. 1969, T. J. Cohn (ANSP). Allotype: female. Same data as holotype (ANSP). Paratypes: One male, 2 females, same data as holotype (ANSP). Habitat.—Specimens were collected at about 600 ft.( 200 m) of elevation in the Guajataca State forest, near Isabela, Puerto Rico. This area is substantially lower than for the three other species. Vegetation there is mostly wet tropical forest. In a visit to this reserve and search around several trails by the senior author and Santo Navarro in October 2001, this forest was found to be rather dry and no specimens of these grasshoppers were encountered.Published as part of Perez-Gelabert, Daniel E. & Otte, Daniel, 2003, Tergoceracris, a new genus and six new species of montane grasshoppers (Orthoptera: Acrididae: Ommatolampinae) from Dominican Republic and Puerto Rico, pp. 1-31 in Zootaxa 155 on pages 6-7, DOI: 10.5281/zenodo.15697
Monthly maps of air temperature and air humidity of the southern slopes of Kilimanjaro, Tanzania
No full textMonthly maps of air temperature and air humidity of the southern slopes of Kilimanjaro, Tanzania. The dataset is part of our study on eco‐meteorological characteristics of the southern slopes of Kilimanjaro, Tanzania ([https://doi.org/10.1002/joc.4552]). (1) ta200_kriging.zip The dataset contains interpolate monthly air temperature maps using universal kriging with elevation, aspect, slope, sky‐view factor and mean monthly normalized difference vegetation index (NDVI) as external drift variables. This corresponds to step 5 in chapter 3.1 of [https://doi.org/10.1002/joc.4552]. (2) rh200_kriging.zip The dataset contains interpolate monthly air humidity maps using universal kriging with elevation, aspect, slope, sky‐view factor and mean monthly normalized difference vegetation index (NDVI) as external drift variables. This corresponds to step 5 in chapter 3.1 of [https://doi.org/10.1002/joc.4552]. (3) ta200_kriging_multi-year_average.zip and rh200_kriging_multi-year_average.zip The dataset contains multi-year monthly averages from (1) and (2) and a map of the multi-year annual mean air temperature and humidity. This corresponds to step 6 in chapter 3.1 of [https://doi.org/10.1002/joc.4552]. For the datasets (1) and (2), we used 5-min measurements between 2011 and 2014 of 52 climate stations that distributed across the southern slopes of Mt. Kilimanjaro. We aggregated the 5-min measurements to hourly observations and filled existing gaps of up to 1 year through multivariate regression using the five nearest stations. We aggregated the gap-filled hourly data to daily averages if at least 22 h of valid records exist for that day at a specific station. Finally, we aggregated the daily averages to monthly averages if a single month has at least 20 valid daily records
Seasonal and long-term vegetation dynamics from 1-km GIMMS-based NDVI time series at Mt. Kilimanjaro, Tanzania
No full textThis dataset consists of GeoTIFF fille for GIMMS NDVI downscaled record (1982–2011) that was resampled from 8 km to 1 km spatial resolution
Building blocks for atomically assembled magnetic and electronic artificial lattices
No full textThis thesis focuses on possible platforms for a bottom-up approach towards realizing and characterizing atomically assembled magnetic and electronic artificial lattices. For this, we make use of the scanning tunneling microscope (STM), which provides a local probe of the magnetic and electronic properties of the sample and allows for the atom-by-atom construction of extended lattices. On the one hand, to address avenues for constructing extended spin lattices, we study single Fe atoms coordinated on the four-fold symmetric nitrogen binding site of the Cu2N/Cu3Au surface—a system which permits large-scale atomic assembly, and allows for independent access to both the orbital and spin degrees of freedom. On the other hand, we investigate the viability of laterally confined vacuum resonances on the chlorinated Cu(100) surface as a basis for constructing electronic lattices. We atomically assemble dimers and trimers of various geometries to determine the tight-binding parameters, and as a proof of concept, experimentally realize a looped Su-Schrieffer–Heeger chain using this platform. These studies are made possible by means of a low-temperature, ultra-high vacuum STM, which allows for atom manipulation and, via spectroscopic techniques, permits us to locally probe the sample density of states and detect inelastic excitations of the spin and orbital angular momentum.QN/Otte La
Magnetic adatoms as building blocks for quantum magnetism
No full textPhysics at the level of an atom is dominated by laws of quantum mechanics. Often, this is entangled with a high complexity in behavior of the systems at that length scale. Unravelling the properties of a material at the atomic level is, therefore, a challenging task that easily supersedes current computational capabilities. A route to circumvent this problem is found in physical realization of simpler quantum systems that are representative of the complex quantum systems one is interested in. These simpler physical systems, unlike their more complex counterparts, can actually be measured and information about the complex system, otherwise inaccessible, gained. This thesis describes experimental work focusing mainly on the property of magnetism in spin chains. To mimic these complex systems, we employ a scanning tunneling microscope (STM) to build atomic chains on solid state surfaces and probe their magnetic properties. The intrinsic strength of STM in building and testing structures with single atom precision makes STM a great candidate for simulation of complex quantum systems. In addition to STM having a role of a quantum simulator, I present work supporting STM as a control device determining the very existence of the magnetic excitations of the atom it measures. Finally, I present experimental findings that suggest we are able to probe the magnetic excitations of the atom with subatomic resolution. In summary, this thesis work presents STM as a powerful probing and control tool for studies on quantum magnetism at the level of a single atom.QN/Otte La
Airorne LiDAR and Hyperspectral data of the southern slopes of Mt. Kilimanjaro, Tanzania
No full textThe LiDAR and hyperspectral data set were acquired during two missions with a Riegl LMS-Q780 sensor and a HYSPEX imaging spectrometer (400 nm to 1,000 nm; 158 bands). The first campaign was flown between March 25 to March 27 2015 and covered the study area below 2,500 m a.s.l, the second between November 10 and November 13 2016 and covered the remaining study plots. To read more about the LiDAR data please refer: doi:10.3390/rs14030786
Paragryllus (Paragryllus) eclogos Otte 2006
No full textParagryllus (Paragryllus) eclogos Otte, 2006 Comments. Unfortunately, this species is very poorly described, and the sparse data are confusing, perhaps erroneous and not informative: e.g., “ File teeth with long wings” (how can a stridulatory file or teeth file have long wings? There is evidence of a lapse in character, perhaps the author was referring to the fact that the insect has long wings.). “With no obvious metanotal glands. With small inner and no outer tympanum” (this character must be reviewed in the type specimen; once the other described and valid species have tympana on both sides of the fore tibia). “Antennae with bristles ”. It is necessary to redescribe this species, detailing and reviewing the morphological characteristics. Another problem is the holotype specimen which was designated a female, but it is actually a male. The female is not known.Published as part of Cadena-Castañeda, Oscar J., Páez, Geraldine, Buitrago, Oscar, Quintana-Arias, Ronald Fernando & Tavares, Gustavo Costa, 2021, Studies of Neotropical crickets: New Paragryllina taxa (Orthoptera: Phalangopsidae) with comments on several previously described species, pp. 60-76 in Zootaxa 5081 (1) on page 65, DOI: 10.11646/zootaxa.5081.1.2, http://zenodo.org/record/576929
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