Generation of broadband THz pulses in organic crystal OH1 at room temperature and 10 K

We studied the effects of cryogenic cooling of a 2-[3-(4-hydroxystyryl)-5, 5-dimethylcyclohex-2-enylidene] malononitrile (OH1) crystal on the generation of broadband THz pulses via collinear optical rectification of 1350 nm femtosecond laser pulses. Cooling of the OH1 crystal from room temperature to 10 K leads to a ~10% increase of the pump-to-THz energy conversion efficiency and a shift of the THz pulse spectra to a higher frequency range. Both effects are due the temperature variation of THz absorption and the refractive index of the OH1 crystal. This conclusion has been verified by temperature dependent measurements of the linear absorption in the THz frequency region

Design of efficient single-stage chirped pulse difference frequency generation at 7μm, driven by a dual wavelength Ti:sapphire laser

We present simulations for a design of a high-energy single-stage mid-IR difference frequency generation adapted to a two-color Ti:sapphire amplifier system. The optimized mixing process is based on chirped pulse difference frequency generation (CP-DFG), allowing for a higher conversion efficiency and reduced two-photon absorption losses. The numerical start-to-end simulations include stretching, chirped pulse difference frequency generation and pulse compression. Realistic design parameters for commercially available nonlinear crystals (GaSe, AgGaS2, LiInSe2, LiGaSe2) are considered. Compared with conventional unchirped DFG directly pumped by Ti:sapphire technology, we predict a threefold increase in the quantum efficiency. Our CP-DFG scheme provides up to 340μJ pulse energy directly at 7.2μm when pumped with 8mJ and supports a bandwidth of up to 350nm. The resulting 240fs mid-IR pulses are inherently phase stable

EVALUASI KESESUAIAN LAHAN UNTUK RUAS JALAN SOLO-PURWODADI DI KECAMATAN GONDANGREJO KABUPATEN KARANGANYAR TAHUN 2017

ABSTRAK Wiji Pitono, K5412079. EVALUASI KESESUAIAN LAHAN UNTUK RUAS JALAN SOLO-PURWODADI DI KECAMATAN GONDANGREJO KABUPATEN KARANGANYAR TAHUN 2017 (Sebagai suplemen bahan pembelajaran Geografi kelas XI SMA KI 3, KD 3.7 mengevaluasi tindakan yang tepat dalam pelestarian lingkungan hidup kaitannya dengan pembangunan yang berkelanjutan, materi pokok implementasi pembangunan berkelanjutan). Skripsi, Surakarta: Fakultas Keguruan dan Ilmu Pendidikan Universitas Sebelas Maret Surakarta, Desember 2017. Penelitian ini dilaksanakan di sepanjang ruas jalan Solo-Purwodadi yang terletak di Kecamatan Gondangrejo dengan tujuan, (1) Mengetahui kesesuaian lahan untuk ruas jalan Solo – Purwodadi Kecamatan Gondangrejo. (2) Mengetahui arahan pengelolaan jalan untuk ruas jalan Solo-Purwodadi Kecamatan Gondangrejo. Metode penelitian yang dipergunakan adalah metode survei dengan tekhnik pengambilan sampel bertujuan (puposive sampling) dengan satuan lahan yang dilewati ruas jalan Solo-Purwodadi sebagai stratumnya. Pendekatan penelitian yang diergunakan adalah deskriptif survei. Satuan pemetaan dalam penelitian ini adalah satuan lahan. Satuan lahan diperoleh dengan melakukan tumpangsusun (overlay) dari peta geologi, peta tanah, peta lereng, dan peta penggunaan lahan. Hasil penelitian menunjukan bahwa daerah penelitian terdapat 80 satuan lahan. Satuan lahan yang dilalui ruas jalan Solo-Purwodadi sebanyak 8 satuan lahan. Penelitian ini sampai pada tingkatan subkelas kesesuaian lahan. Berdasarkan hasil analisis data diperoleh 1 satuan lahan termasuk kelas Sedang (S) dan 7 satuan lahan termasuk kelas Jelek (J). Terdapat 5 subkelas kesesuaian lahan pada lokasi penelitian yaitu Jpc, Jkpc, Jp, Skr, dan Jc. Faktor pembatas pada daerah penelitian ada 4 yaitu penggenangan (p), potensi mengembang-mengerut tanah (c), kedalaman batuan (k), dan batuan dengan diameter >7,5 cm (r). Pengelolaan jalan pada penelitian ini berupa saran perbaikan jalan berdasarkan masing-masing faktor pembatas. Faktor pembatas berupa penggenangan dapat diatasi dengan cara perbaikan drainase yang ideal dan dengan merencanakan saluran drainase bawah tanah sehingga dapat mencegah adanya air yang menggenangi badan jalan. Potensi mengembang-mengerut tahan dapat diatasi dengan cara (1) Membuang lapisan tanah atas dan menggantinya dengan tanah dari tempat lain yang tidak memiliki potensi mengembang-mengerut, (2) Melakukan perbaikan tanah dengan tujuan menurunkan indeks plastisitas tanah. Kedalaman batuan berkaitan dengan pondasi jalan, hal ini dapat diatasi dengan penggunaan material pondasi yang lebih kuat seperti misalnya beton. Batuan dengan diameter > 7,5 cm, daerah yang memiliki jumlah batuan yang banyak menandakan bahwa pada daerah tersebut memiliki tingkat erosi yang tinggi, guna mengurangi dampak erosi pada jalan dapat dilakukan dengan pembuatan tanggul penahan pa da sisi-sisi jalan. Kata Kunci: Evaluasi Kesesuaian Lahan, Jalan, Pengelolaan Jala

Cross-Species Single-Cell Analysis Reveals Divergence of the Primate Microglia Program

Summary Microglia, the brain-resident immune cells, are critically involved in many physiological and pathological brain processes, including neurodegeneration. Here we characterize microglia morphology and transcriptional programs across ten species spanning more than 450 million years of evolution. We find that microglia express a conserved core gene program of orthologous genes from rodents to humans, including ligands and receptors associated with interactions between glia and neurons. In most species, microglia show a single dominant transcriptional state, whereas human microglia display significant heterogeneity. In addition, we observed notable differences in several gene modules of rodents compared with primate microglia, including complement, phagocytic, and susceptibility genes to neurodegeneration, such as Alzheimer’s and Parkinson’s disease. Our study provides an essential resource of conserved and divergent microglia pathways across evolution, with important implications for future development of microglia-based therapies in humans

The global abundance of tree palms

Aim Palms are an iconic, diverse and often abundant component of tropical ecosystems that provide many ecosystem services. Being monocots, tree palms are evolutionarily, morphologically and physiologically distinct from other trees, and these differences have important consequences for ecosystem services (e.g., carbon sequestration and storage) and in terms of responses to climate change. We quantified global patterns of tree palm relative abundance to help improve understanding of tropical forests and reduce uncertainty about these ecosystems under climate change. Location Tropical and subtropical moist forests. Time period Current. Major taxa studied Palms (Arecaceae). Methods We assembled a pantropical dataset of 2,548 forest plots (covering 1,191 ha) and quantified tree palm (i.e., ≥10 cm diameter at breast height) abundance relative to co‐occurring non‐palm trees. We compared the relative abundance of tree palms across biogeographical realms and tested for associations with palaeoclimate stability, current climate, edaphic conditions and metrics of forest structure. Results On average, the relative abundance of tree palms was more than five times larger between Neotropical locations and other biogeographical realms. Tree palms were absent in most locations outside the Neotropics but present in >80% of Neotropical locations. The relative abundance of tree palms was more strongly associated with local conditions (e.g., higher mean annual precipitation, lower soil fertility, shallower water table and lower plot mean wood density) than metrics of long‐term climate stability. Life‐form diversity also influenced the patterns; palm assemblages outside the Neotropics comprise many non‐tree (e.g., climbing) palms. Finally, we show that tree palms can influence estimates of above‐ground biomass, but the magnitude and direction of the effect require additional work. Conclusions Tree palms are not only quintessentially tropical, but they are also overwhelmingly Neotropical. Future work to understand the contributions of tree palms to biomass estimates and carbon cycling will be particularly crucial in Neotropical forests

High-repetition-rate femtosecond optical parametric chirped-pulse amplifier in the mid-infrared

ISSN:0946-2171ISSN:1432-0649ISSN:0721-7269ISSN:0340-379