931 research outputs found
Gender and the Outdoors: An International Conversation
Over the past two to three decades in outdoor education circles, there has been a gradual swell of interest in bringing a gender lens to the examination of issues, theory and practice within the field. Although feminist theory has been subjected to lively debate and undergone sophisticated shifts in the ways of conceptualizing and analyzing gender, much of the literature coming out of the outdoor field and much of our practice is still centered on women and difference. As Bell (1997) so clearly asked, “Has the dialogue on the nature of gender and associated social issues not changed in the past decade?” A group of international researchers, educators and practitioners discussed gender theory and practice in their “neck of the woods” and challenged attendees to ask that question again today
Pediatric low-grade glioma models: advances and ongoing challenges
Pediatric low-grade gliomas represent the most common childhood brain tumor class. While often curable, some tumors fail to respond and even successful treatments can have life-long side effects. Many clinical trials are underway for pediatric low-grade gliomas. However, these trials are expensive and challenging to organize due to the heterogeneity of patients and subtypes. Advances in sequencing technologies are helping to mitigate this by revealing the molecular landscapes of mutations in pediatric low-grade glioma. Functionalizing these mutations in the form of preclinical models is the next step in both understanding the disease mechanisms as well as for testing therapeutics. However, such models are often more difficult to generate due to their less proliferative nature, and the heterogeneity of tumor microenvironments, cell(s)-of-origin, and genetic alterations. In this review, we discuss the molecular and genetic alterations and the various preclinical models generated for the different types of pediatric low-grade gliomas. We examined the different preclinical models for pediatric low-grade gliomas, summarizing the scientific advances made to the field and therapeutic implications. We also discuss the advantages and limitations of the various models. This review highlights the importance of preclinical models for pediatric low-grade gliomas while noting the challenges and future directions of these models to improve therapeutic outcomes of pediatric low-grade gliomas
Thermal Conductivity and Specific Heat of the Spin-Ice Compound DyTiO: Experimental Evidence for Monopole Heat Transport
Elementary excitations in the spin-ice compound DyTiO can be
described as magnetic monopoles propagating independently within the pyrochlore
lattice formed by magnetic Dy ions. We studied the magnetic-field dependence of
the thermal conductivity {\kappa}(B) for B || [001] and observe clear evidence
for magnetic heat transport originating from the monopole excitations. The
magnetic contribution {\kappa}_{mag} is strongly field-dependent and correlates
with the magnetization M(B). The diffusion coefficient obtained from the ratio
of {\kappa}_{mag} and the magnetic specific heat is strongly enhanced below 1 K
indicating a high mobility of the monopole excitations in the spin-ice state.Comment: 5 pages, 4 figure
μ-Carbonato-bis(bis{2-[(diethylamino)methyl]phenyl}bismuth(III))
The molecular structure of the title compound, [Bi2(C11H16N)4(CO3)], consists of a symmetrically bridging carbonato group which binds two [2-Et2NCH2C6H4]2Bi units that are crystallographically related via a twofold rotation axis bisecting the carbonate group. The two Bi atoms and two of the C atoms directly bonded to bismuth are quasi-planar [deviations of 0.323 (1) and 0.330 (9)Å for the Bi and C atoms, respectively] with the carbonate group. The remaining two ligands are in a trans arrangement relative to the quasi-planar (CBi)2CO3 system. The metal atom is strongly coordinated by the N atom of one pendant arm [Bi—N = 2.739 (6) Å], almost trans to the O atom, while the N atom of the other pendant arm exhibits a weaker intramolecular interaction [Bi⋯N = 3.659 (7) Å] almost trans to a C atom. If both these intramolecular N→Bi interactions per metal atom are considered, the overall coordination geometry at bismuth becomes distorted square-pyramidal [(C,N)2BiO cores] and the compound can be described as a hypervalent 12-Bi-5 species. Additional quite short intramolecular Bi⋯O interactions are also present [3.796 (8)–4.020 (9) Å]. Intermolecular associations through weak η6⋯Bi interactions [Bi⋯centroid of benzene ring = 3.659 (1) Å] lead to a ribbon-like supramolecular association
Quantum Criticality of an Ising-like Spin-1/2 Antiferromagnetic Chain in Transverse Magnetic Field
We report on magnetization, sound velocity, and magnetocaloric-effect
measurements of the Ising-like spin-1/2 antiferromagnetic chain system
BaCoVO as a function of temperature down to 1.3 K and applied
transverse magnetic field up to 60 T. While across the N\'{e}el temperature of
K anomalies in magnetization and sound velocity confirm the
antiferromagnetic ordering transition, at the lowest temperature the
field-dependent measurements reveal a sharp softening of sound velocity
and a clear minimum of temperature at T,
indicating the suppression of the antiferromagnetic order. At higher fields,
the curve shows a broad minimum at T, accompanied by a
broad minimum in the sound velocity and a saturation-like magnetization. These
features signal a quantum phase transition which is further characterized by
the divergent behavior of the Gr\"{u}neisen parameter . By contrast, around the critical field, the
Gr\"{u}neisen parameter converges as temperature decreases, pointing to a
quantum critical point of the one-dimensional transverse-field Ising model.Comment: Phys. Rev. Lett., to appea
High power and spectral purity continuous-wave photonic THz source tunable from 1 to 4.5 THz for nonlinear molecular spectroscopy
We report a diffraction-limited photonic terahertz (THz) source with linewidth \u3c 10 MHz that can be used for nonlinear THz studies in the continuous wave (CW) regime with uninterrupted tunability in a broad range of THz frequencies. THz output is produced in orientation-patterned (OP) gallium arsenide (GaAs) via intracavity frequency mixing between the two closely spaced resonating signal and idler waves of an optical parametric oscillator (OPO) operating near lambda = 2 mu m. The doubly resonant type II OPO is based on a periodically poled lithium niobate (PPLN) pumped by a single-frequency Yb:YAG disc laser at 1030 nm. We take advantage of the enhancement of both optical fields inside a high-finesse OPO cavity: with 10 W of 1030 nm pump, 100 W of intracavity power near 2 mu m was attained with GaAs inside cavity. This allows dramatic improvement in terms of generated THz power, as compared to the state-of-the art CW methods. We achieved \u3e 25 mu W of single-frequency tunable CW THz output power scalable to \u3e 1 mW with proper choice of pump laser wavelength
4-Benzylpiperazin-1-ium chloride chloroform solvate
The ions of the title chloroform-solvated salt, C11H17N2
+·Cl−·CHCl3, are linked by a strong N—H⋯Cl hydrogen bond; the solvent molecule also interacts with the chloride ion through a C—H⋯Cl hydrogen bond. Additionally, neighboring cations form weak hydrogen bonds to the anion, resulting in a supramolecular ribbon that runs along the a axis
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