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Bethlehem, PA, United States

Lehigh University is an American private research university located in Bethlehem, Pennsylvania. It was established in 1865 by businessman Asa Packer and has grown to include studies in a wide variety of disciplines. Its undergraduate programs have been coeducational since the 1971–72 academic year. As of 2014, the university had 4,904 undergraduate students and 2,165 graduate students. Lehigh is considered one of the twenty-four Hidden Ivies in the Northeastern United States.Lehigh is ranked 12th in the nation, according to The Wall Street Journal, in college return on investment . The university has over 680 faculty members; awards and honors recognizing Lehigh faculty and alumni include the Nobel Prize, the Pulitzer Prize, Fulbright Fellowship, and membership in the American Academy of Arts & science and the National Academy of science.The university has four colleges: the P.C. Rossin College of Engineering and Applied Science, the College of Arts and science, the College of Business and Economics, and the College of Education. The College of Arts and science is the largest college today, home to roughly 40% percent of the university's students. The university offers a variety of degrees, including Bachelor of Arts, Bachelor of Science, Master of Arts, Master of Science, Master of Business Administration, Master of Engineering, Master of Education, and Doctor of Philosophy. Wikipedia.

The sensitivity of peatland water-table depth reconstructions to past hydroclimate variability was assessed by comparing 210Pb-dated, testate amoeba-based reconstructions of water-table depth with instrumental records of temperature, precipitation, and Palmer Drought Severity Index (PDSI). Comparisons were made for the past century at five sites in the western Great Lakes region of North America. The primary objectives were (1) to assess the relative influence of temperature and precipitation on proxy records from these systems, (2) compare an integrated index of past moisture variability, PDSI, to records of peatland surface-moisture, and (3) compare the relative climate sensitivity of paleohydrological records from a raised bog and two types of kettle peatland, including those with and without floating peat mats. Results indicated that the raised bog surface-moisture reconstructions were most strongly correlated with PDSI, with precipitation variability more important than temperature variability. Proxy records from two non-floating kettle peatlands were also correlated with PDSI, although the importance of precipitation and temperature varied between the two sites. Records from floating mats were not correlated with instrumental climate records, although patterns suggest that additional research is needed to assess the sensitivity of these systems to high-magnitude or prolonged drought events. Although the relative importance of precipitation and temperature in controlling peatland surface-moisture conditions may vary in space and time, consistent correlations with PDSI indicate that peatland archives are well suited for studies of past drought variability and should be particularly valuable in humid regions at mid-to-high latitudes where moisture-sensitive records are scarce. © 2009 Elsevier Ltd. All rights reserved.

Large, hydrophilic inorganic ions (mostly polyoxometalate macroions and cationic metal-organic hybrid nanocages) with high solubility in water and/or other polar solvents demonstrate unique solution behaviors. In dilute solutions, they behave significantly different from small simple ions (as described by the Debye-Hückel theory) because the macroions cannot be treated as point charges or large, insoluble colloidal suspensions (usually described by the DLVO theory) because the macroions form homogeneous, stable "real solutions". The size disparity between the macroions and their counterions results in complex macroion-counterion interaction and leads to the self-assembly of macroions into single-layered, hollow, spherical "blackberry" structures. The blackberries, with robust and very stable structures mimicking biological membranes, can adjust their size accurately and reversibly in response to the change of solvent content, charge density on the macroions, or in some cases merely solution pH. The blackberry membrane is permeable to small cations. The inorganic macroions with well-defined size, shape, mass, charge density (even accurately tunable within certain range), and no intramolecular interaction can be treated as simple model systems to understand the intermolecular interaction in polyelectrolyte solutions. The blackberry structures show certain similarities to the spherical virus capsids, from the overall structure to the kinetic properties of formation. © 2010 American Chemical Society.

This paper proposes a novel approach using basal peat ages and carbon (C) accumulation profiles from the world's major peatland regions to decompose C flux terms from time-dependent C pool data observed from peat cores. Our peat-data syntheses show that the total peat C pools are 547 GtC, 50 GtC, and 15 GtC for northern, tropical and southern peatlands, respectively. The modeled net C balance (NCB) has a mean value of 41.8 TgC/yr for northern peatlands during the Holocene, ranging from 83.1 TgC/yr in the early Holocene around 9 ka (1 ka = 1000 cal. yr BP) to 21.5 TgC/yr around 2 ka, a temporal pattern mostly owing to the delayed effect of long-term decay of previously accumulated peat C. NCB from tropical and southern peatlands represents much smaller terms, mostly less than 10 TgC/yr. Northern peatlands represent about 90% of global total peatland C pool of 612 GtC and >90% of global peatland NCB. Our bottom-up global peatland synthesis indicates a decrease in rates of peatland area expansion and reduced CH4 emissions during the late Holocene, thus lending support for an anthropogenic source of late-Holocene CH4 rise. The C balance analysis of global peatland data indicates a cumulative net C uptake of 272 GtC in the early Holocene (11-7 ka), 151 GtC at 7-4 ka, and 116 GtC after 4 ka. The large cumulative fluxes and significant variations throughout the Holocene could greatly contribute to the observed atmospheric CO 2 and δ 13CO 2 patterns derived from Antarctic ice cores. Thus, global mass-balance calculations or climate-carbon cycle simulations have to consider these large net C uptake terms from global peatlands and their variations over the Holocene. © The Author(s) 2011.

Ding Y.J.,Lehigh University
Optics Letters | Year: 2012

We show that backward difference-frequency generation can be exploited to achieve phase conjugation in a secondorder nonlinear medium. The backward configuration can be utilized to achieve broadband quasi-phase-matching, compared with the forward counterpart. Our calculation shows that a nonlinear reflectivity of close to 100% is achievable from a laser emitting an output power of ∼1 mW. Such an efficient phase conjugator is made feasible by placing the nonlinear medium inside a pump laser cavity. In addition, a Fabry-Perot resonator at the input frequency is used to significantly improve the nonlinear reflectivity. © 2012 Optical Society of America.

Rotkin S.V.,Lehigh University
Annual Review of Physical Chemistry | Year: 2010

Helical wrapping of single-strand DNA around single-wall nanotubes (SWNTs) results in the symmetry breaking and modification of the nanotube band structure. Empirical tight-binding theory was employed to investigate this symmetry breaking and modulation of the electronic and optical properties of a SWNT in the field of an ionized DNA. The model allows the computation of the polarization component of the hybrid's energy of cohesion, with a typical value of 0.5 eV per DNA base. A screening parameter that quantifies the response of the SWNT electrons to the DNA perturbation was obtained. SWNT symmetry breaking shows up in the optical absorption for light polarized across the SWNT axis. In addition, circular dichroism is predicted for DNA-SWNT hybrids, even when the nanotube itself is achiral. These optical effects may be used for experimental determination of the DNA wrapping. Copyright © 2010 by Annual Reviews. All rights reserved.

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