38 research outputs found
The Daily Patterns of Emergency Medical Events
This study examines population level daily patterns of time-stamped emergency medical service (EMS) dispatches to establish their situational predictability. Using visualization, sinusoidal regression, and statistical tests to compare empirical cumulative distributions, we analyzed 311,848,450 emergency medical call records from the U.S. National Emergency Medical Services Information System (NEMSIS) for years 2010 through 2022. The analysis revealed a robust daily pattern in the hourly distribution of distress calls across 33 major categories of medical emergency dispatch types. Sinusoidal regression coefficients for all types were statistically significant, mostly at the p \u3c 0.0001 level. The coefficient of determination () ranged from 0.84 and 0.99 for all models, with most falling in the 0.94 to 0.99 range. The common sinusoidal pattern, peaking in mid-afternoon, demonstrates that all major categories of medical emergency dispatch types appear to be influenced by an underlying daily rhythm that is aligned with daylight hours and common sleep/wake cycles. A comparison of results with previous landmark studies revealed new and contrasting EMS patterns for several long-established peak occurrence hours--specifically for chest pain, heart problems, stroke, convulsions and seizures, and sudden cardiac arrest/death. Upon closer examination, we also found that heart attacks, diagnosed by paramedics in the field via 12-lead cardiac monitoring, followed the identified common daily pattern of a mid-afternoon peak, departing from prior generally accepted morning tendencies. Extended analysis revealed that the normative pattern prevailed across the NEMSIS data when re-organized to consider monthly, seasonal, daylight-savings vs civil time, and pre-/post- COVID-19 periods. The predictable daily EMS patterns provide impetus for more research that links daily variation with causal risk and protective factors. Our methods are straightforward and presented with detail to provide accessible and replicable implementation for researchers and practitioners
Control of developmentally primed erythroid genes by combinatorial co-repressor actions
How transcription factors (TFs) cooperate within large protein complexes to allow rapid modulation of gene expression during development is still largely unknown. Here we show that the key haematopoietic LIM-domain-binding protein-1 (LDB1) TF complex contains several activator and repressor components that together maintain an erythroid-specific gene expression programme primed for rapid activation until differentiation is induced. A combination of proteomics, functional genomics and in vivo studies presented here identifies known and novel co-repressors, most notably the ETO2 and IRF2BP2 proteins, involved in maintaining this primed state. The ETO2-IRF2BP2 axis, interacting with the NCOR1/SMRT co-repressor complex, suppresses the expression of the vast majority of archetypical erythroid genes and pathways until its decommissioning at the onset of terminal erythroid differentiation. Our experiments demonstrate that multimeric regulatory complexes feature a dynamic interplay between activating and repressing components that determines lineage-specific gene expression and cellular differentiation
Aluminum oxide as passivation and gate insulator in GaAs-based field-effect transistors prepared in situ by metal-organic vapor deposition
Application of GaAs-based metal-oxide-semiconductor (MOS) structures, as a "high carrier mobility" alternative to conventional Si MOS transistors, is still hindered due to difficulties in their preparation with low surface/interface defect states. Here, aluminum oxide as a passivation and gate insulator was formed by room temperature oxidation of a thin Al layer prepared in situ by metal-organic chemical vapor deposition. The GaAs-based MOS structures yielded two-times higher sheet charge density and saturation drain current, i.e., up to 4 x 10 12 cm(-2) and 480 mA/mm, respectively, than the counterparts without an oxide surface layer. The highest electron mobility in transistor channel was found to be 6050 cm(2)/V s. Capacitance measurements, performed in the range from 1 kHz to 1 MHz, showed their negligible frequency dispersion. All these results indicate an efficient suppression of the defect states by in situ preparation of the semiconductor structure and aluminum oxide used as a passivation and gate insulator. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.3701584
PERSISTENSI CENDAWAN Metarhizium anisopliae (Metsch.) PADA TANAH GAMBUT SERTA TINGKAT PATOGENISITASNYA TERHADAP LARVA Tenebrio molitor (Linn.) di LABORATORIUM
Metarhizium anisopliae (Metsch.) merupakan agen hayati yang sering digunakan untuk mengendalikan serangga Coleoptera, akan tetapi belum banyak informasi tentang kemampuan konidia untuk bertahan di tanah gambut dan tetap mampu mengendalikan hama. Penelitian bertujuan untuk mengetahui daya persistensi cendawan M. anisopliae (Metsch.) di tanah gambut, terhadap serangga hama Tenebrio molitor. Pengujian meliputi uji pendahuluan pengembalian daya virulensi cendawan, dilanjutkan perlakuan menggunakan suspensi 9,056x107 konidia/ 1ml yang dilakukan untuk melihat persistensinya dengan lama perlakuan inkubasi 1, 3, 5, 7, 10, 14, dan hari ke 21. Setiap perlakuan diulang 3 kali, dengan jumlah larva uji 90 ekor per perlakuan. Aplikasi M. anisopliae (Metsch.) dengan cara menyemprotkan suspensi konidia ke gambut steril, untuk selanjutnya diinkubasi. Kemudian larva uji dimasukkan ke dalam toples yang berisi media gambut sesuai hari perlakuan. Variabel pengamatan meliputi persentase kematian larva, pupa dan imago yang dihasilkan, jumlah konidia yang tumbuh setelah masa inkubasi, kadar air media, nilai LT50, dan waktu paruh dari M. anisopliae. Data mortalitas dianalisis dengan rumus kematian terkoreksi Abbot, dan analisis probit serta regresi linear untuk menentukan LT 50 % dan waktu paruh. Hasil penelitian menunjukkan pada perlakuan inkubasi suspensi hari ke- 14 dan 21 hari mortalitasnya menurun dengan persentase kematian hanya 90% dan 82,2%, dibandingkan inkubasi hari ke 1 hingga hari ke 10 yang persentase mortalitasnya 100%. Makin lama masa inkubasi konidia pada media, maka persentase mortalitas makin menurun, sedangan pupa dan imago yang dihasilkan makin tinggi, selain itu jumlah konidia yang tumbuh semakin rendah seiring dengan semakin tingginya kehilangan air. Nilai LT50% suspensi konidia 9,056x107/ml adalah 32,78 hari, sedangkan waktu paruhnya adalah 83,035 hari. Kata Kunci : Metarhizium anisopliae (Metsch.), tanah gambut, persistensi, Tenebrio molitor (Metsch.)
RF Performance of InAlN/GaN HFETs and MOSHFETs with fTxLG up to 21GHz*um
The RF performance of lattice-matched InAlN/GaN heterostructure field-effect transistors (HFETs) and Al2O3/InAlN/GaN metal-oxide-semiconductor HFETs (MOSHFETs) with varied gate length was evaluated. The current gain cutoff frequency f(T) and the maximum oscillation frequency f(max) for the HFETs with 0.3-mu m gate length were 54 and 58 GHz, respectively. An increase of f(T) to 61 GHz and of f(max) to 70 GHz was obtained for the MOSHFETs. The HFETs and MOSHFETs with different gate length yielded an f(T) x L-G product of 18 and 21 GHz . mu m, respectively. These are higher values than reported yet on InAlN/GaN devices and similar to those known for AlGaN/GaN HFETs
Thermally induced voltage shift in capacitance-voltage characteristics and its relation to oxide/semiconductor interface states in Ni/Al2O3/InAlN/GaN heterostructures
The Ni/Al2O3/InAlN/AlN/GaN metal-oxide-semiconductor heterostructure (MOS-H) is investigated using capacitance-voltage and capacitance-time characteristics in the temperature range of 25-300 degrees C. An anomalous positive voltage shift of the capacitance-voltage curve with increasing temperature was observed and attributed to the hole emission from the oxide/semiconductor interface states. Distribution of the interface states density, Dit(E), at the Al2O3/InAlN interface was evaluated using a modification of the constant-capacitance deep-level transient spectroscopy. The MOS-H capacitor threshold voltage shift under negative bias was repetitively recorded as a function of time at elevated temperatures. Dit in the range of 0.1-3 x 10(13) eV(-1) cm(-2) was determined
InAIN/GaN metal-oxide-semiconductor high electron mobility transistor with Al2O3 insulating films grown by metal organic chemical vapor deposition using Ar and NH3 carrier gases
Al2O3 thin films were deposited by a metal organic chemical vapour deposition on InAIN/GaN heterostructures using Ar or NH3 as a carrier gas. Effects of NH3 and Ar carrier gases on the electrical and structural properties of Al2O3/InAIN/GaN HEMT devices were investigated by current voltage, current collapse, and Auger electron spectroscopy measurements. Al2O3 deposited using Ar as a carrier gas leads to a substantial gate leakage current reduction with no increase of the current collapse compare to Schottky gate based HEMT. On the other hand, HEMT electrical performance shows degradation if NH3 carrier gas is used. Similarly, Auger electron spectroscopy revealed presence of carbon on InAIN surface when NH3 carrier gas was applied. It is suggested that the formation of carbon-related traps on the InAIN surface takes place in the early stages of the Al2O3 deposition with NH3 carrier gas that strongly influences the HEMT performance. (C) 2009 American Vacuum Society. [DOI: 10.1116/1.3021034
Gate insulation and drain current saturation mechanism in InAlN/GaN metal-oxide-semiconductor high-electron-mobility transistors
The authors investigate 2 mu m gate-length InAlN/GaN metal-oxide-semiconductor high-electron-mobility transistors (MOS HEMTs) with 12 nm thick Al2O3 gate insulation. Compared to the Schottky barrier (SB) HEMT with similar design, the MOS HEMT exhibits a gate leakage reduction by six to ten orders of magnitude. A maximal drain current density (I-DS=0.9 A/mm) and an extrinsic transconductance (g(me)=115 mS/mm) of the MOS HEMT also show improvements despite the threshold voltage shift. An analytical modeling shows that a higher mobility of electrons in the channel of the MOS HEMT and consequently a higher number of electrons attaining the velocity saturation may explain the observed increase in g(me) after the gate insulation. (C) 2007 American Institute of Physics