ライフサイエンスコーパス: decay with

1 rophylls absorbing around 687 nm, thereafter decaying with 4-20 ps lifetimes, independently of excita

2 0 nm (near the red edge of the bulk antenna) decays with 590 fs kinetics; the corresponding anisotrop

3 lifetime of 1-21 days accompanied by a slow decay with a 1/e lifetime of 21-5028 days (47% of sample

4 ravitreal moxifloxacin showed an exponential decay with a half-life of 1.72 hours.

5 s, and CD4(+) T cells with intact proviruses decay with a half-life of 19 mo, which is still shorter

6 ng over weeks 60 to 384: an initial phase of decay with a half-life of 39 weeks and a subsequent phas

7 Y21F mutant protein exhibits a fluorescence decay with a lifetime of 0.6 ns.

8 ollection shows monoexponential fluorescence decay with a lifetime of 1.0 ns.

9 -1) to give C60 singlet excited states which decay with a lifetime of 1.2 ns to give very long-lived

10 t not Y21F also exhibits slower fluorescence decay with a lifetime of 1.7 ns.

11 olecules are produced within 100 fs and then decay with a lifetime of 400 ps or more.

12 negatively charged QDs show band edge trion decay with a lifetime of 690 +/- 31 ps and slower 1P to

13 1.7 mus) accounts for only 3-8% of the total decay with a longer-lived component having a time consta

14 ng replication-competent HIV-1 were found to decay with a mean half-life of approximately 6 months, c

15 itrosyl form following a first-order kinetic decay with a measured kinetic constant of k = 0.017 s(-1

16 tional relaxation oscillators that typically decay with a single time constant, the feedback in the E

17 recapitulates the ubiquitous power-law rate decay with a slope of -0.65.

18 The miniature EPSCs decay with a time constant of 13.0 +/- 1.1 ms whereas th

19 ctra of the S(1) state of the porphyrin that decay with a time constant of 17 ps (M = Mg) or 24 ps (M

20 nm that is best fit to a single-exponential decay with a time constant of 55 +/- 6 ns.

21 nts showed a fast-rising phase followed by a decay with a time constant of approximately 2-3 sec.

22 exhibits a nearly concentration-independent decay with a time constant of ~350 ps.

23 rimental evidence of a stretched exponential decay with a universal exponent 1/3 in DLS for all the p

24 arization to +10 mV led to triphasic [Ca2+]i decay, with a fast-slow-fast pattern.

25 tion of any of the absorption peaks: a rapid decay, with a time constant of 1 ps or less, and a slow

26 a time constant of 1 ps or less, and a slow decay, with a time constant that can be longer than 300

27 larization the ensemble-averaged LCC current decayed with a fast and a slow exponential component.

28 me constant of 7.2+/-0.7 ms, while the mIPSC decayed with a fast time constant of 5.3+/-0.4 ms in the

29 The evoked IPSC decayed with a fast time constant of 7.2+/-0.7 ms, while

30 The VA.+ signal decayed with a first-order decay constant of 1.76 s-1, i

31 to 0.021 Hz) in <10 s after stimulation and decayed with a half time <20 s, indicating that the time

32 virion production, assessed by p24 release, decayed with a half-life of 2 days.

33 ranosylbenzimidazole, tyrosinase mRNA levels decayed with a half-life of 4-5 h.

34 ffect of tracing on rate of return to clinic decayed with a half-life of 7.0 days after tracing (95%

35 ose per gram [%ID/g]) at 2 h was 7 %ID/g and decayed with a half-life of 72 h, whereas blood %ID/g ra

36 Responses in SCN neuronal activity decayed with a half-max time of ~9 min for UV light and

37 ec after the start of the depolarization and decayed with a mean time constant of 8.5 msec.

38 th a rate constant of 4.0 +/- 0.2 s (-1) and decayed with a rate constant of 3.7 +/- 0.2 s (-1).

39 te formed with a rate constant of 32 s-1 and decayed with a rate constant of 6.6 s-1.

40 nt of 140 s-1; the QB semiquinone EPR signal decayed with a rate constant of about 5 s-1.

41 Eye movement velocity decayed with a similar exponential trajectory (time cons

42 yme or was generated using hydrogen peroxide decayed with a t1/2 of 2 days compared with 6 min for wi

43 in dendritic regions <1 microm in length and decayed with a time constant of 0.35 +/- 0.03 s.

44 The AMPA receptor-mediated EPSC decayed with a time constant of 1.99+/-0.16 ms (n = 8).

45 his "resurgent" current peaked in 8 msec and decayed with a time constant of 30 msec.

46 um was seen after each action potential, and decayed with a time constant of about 200 ms in the soma

47 The facilitation decayed with a time constant of approximately 100 msec.

48 n an approximately 2.5-fold enhancement that decayed with a time constant of approximately 200 msec,

49 xotomy-induced synaptic withdrawal phenotype decayed with a time constant of approximately 30 days.

50 and a weaker, but more persistent, form that decayed with a time constant of several seconds.

51 n and in adult neocortical pyramidal neurons decayed with a time constant of tau = 8.0 +/- 2.8s.

52 nt conditions, the evoked EPSC in aniracetam decayed with a time course intermediate between deactiva

53 ransfected beta-globin mRNA was very stable, decaying with a half-life of >360 min.

54 onths and the remainder being long lived and decaying with a half-life of 2690 days (95% CrI 1016-15

55 being short lived, and the long lived phase decaying with a half-life of 6007 days (95% CrI 2826-14

56 (-H)(*) decay is biphasic with one component decaying with a lifetime of approximately 2.2 ms and the

57 ith the fused bifunctional wild type enzyme, decaying with a t1/2 of 10 min at 37 degrees C.

58 This exocytosis was transient in nature, decaying with a time constant of approximately 30 ms.

59 als, appearing within a few milliseconds and decaying with a time constant of approximately 50 ms.

60 ine were also studied, showing biexponential decays with a 1.1 ps component (5%) besides a sub-0.2 ps

61 ts and 2D IR spectra show a new feature that decays with a 110-fs time scale.

62 diate species: I1, which forms in <10 ns and decays with a 200-micros lifetime to I2, which itself su

63 Kinetic analysis shows that I0 decays with a 220 +/- 20 ps lifetime, forming another in

64 Idouble dagger0 decays with a 3 +/- 0.15 ns time constant to form I1.

65 This putative triplet state subsequently decays with a 4-micros time constant into a 390 nm-absor

66 DsrA decays with a half-life of 23 min at 25 degrees C and 4

67 the thermal stability of Rho showed that Rho decays with a half-life on the order of days.

68 blindness mutants, the T94I MII intermediate decays with a half-life that is approximately 8-fold slo

69 lmost equal to its initial value and finally decays with a half-time (approximately 20 s) longer than

70 ution for days, whereas [CoIIIH(2)2iPr(OH)]- decays with a kint=5.9x10-8 M min-1.

71 process, the hydroperoxy-ferric intermediate decays with a large solvent kinetic isotope effect, as e

72 orrespondingly formed radical ion pair state decays with a lifetime of 1.0 +/- 0.1 ns.

73 predict that the probability of self-renewal decays with a logistic kinetic over the life span of a n

74 e demonstrate here that the latent reservoir decays with a mean half-life of 6.3 months in patients w

75 Seventy percent of the initial complex decays with a rate constant greater than 0.05 s-1, and 3

76 Above 255 K, it slowly decays with a rate constant k = 10(7.7+/-0.4) s(-1) x ex

77 A minor component ( approximately 16%) decays with a rate constant of 170 micros.

78 ith a rate constant of 1.2 x 10(7) s(-1) and decays with a rate constant of 5.6 x 10(5) s(-1).

79 damax=450 nm) due to formation of T1K, which decays with a rate of 2.1 x 105 s-1 to form triplet alky

80 2 x 105 s-1 in methanol, whereas nitrene 2a decays with a rate of approximately 91 s-1.

81 onditions, the catalytically competent state decays with a second-order half-life of approximately 15

82 (161)Tb decays with a similar half-life to (177)Lu, but beyond t

83 a single cysteine residue display spin-echo decays with a single phase-memory time T2M and conventio

84 it of the eGFP15eGFP fluorescence anisotropy decays with a stretched exponential decay model (<E(FRET

85 urements indicate that novelty within groups decays with a stretched-exponential law, suggesting the

86 This rescue decays with a t1/2 of approximately 1-1.5 d after gene i

87 e (Q(B)) site is fully occupied, P(+)H(B)(-) decays with a time constant estimated to be in the range

88 ignal for photogenerated electrons on g-C3N4 decays with a time constant of 1/ke' = 660 ps in the mix

89 hat when the intermediate population finally decays with a time constant of 10 mus, it does so with a

90 ing gives rise to a transient discharge that decays with a time constant of 100 msec or less.

91 20 fs after ultraviolet photoexcitation and decays with a time constant of 110 +/- 60 fs.

92 This final state decays with a time constant of 3.8 mus.

93 removed prematurely, the accumulated message decays with a time constant that correlates with the tim

94 es was associated with reduced risk of tooth decay with adjusted hazard ratios of 0.82 (95% CI, 0.78-

95 exhibited biexponential decay with age in gray and white matter regions, except

96 -constrained foraging schedules, and did not decay with age.

97 lectrostatic potential and pair interactions decay with an anisotropic Debye screening length, contra

98 n circulating CD4(+)T cells showed triphasic decay with an initial phase slower than the decay of the

99 d increases in [Pi] induced a biphasic force decay with an initial slow decline (phase 1) and a subse

100 the IkappaB-alpha and IkappaB-beta proteins decayed with an approximate t1/2 of 38 and 76 min, respe

101 the aged LIM/O3 SOA in the 450-600 nm range decayed with an effective half-life of <0.5 h.

102 In contrast, the intact proviral reservoir decayed with an estimated half-life of 4.9 y.

103 latency of 1.2 s, a rise time of 2.5 s, and decayed with an exponential time constant of 15 s.

104 Facilitation decayed with an intrinsic time constant of approximately

105 rophysiologically measured cortical activity decays with an approximately 1 /f(X) function.

106 dienylidene (4), and this absorption feature decays with an approximately 30 ps time constant in hexa

107 For the inactive protein state, C(t) decays with an ultrafast component, close to bulk-type b

108 rupt (subdaily) excursions and biexponential decay with approximately 1-day and 1-week time constants

109 otide or a duplex undergoes a bi-exponential decay with approximately 4 and approximately 1 ns lifeti

110 y, we find that most dORFs are substantially decayed, with approximately 90% having two or more disab

111 -6ANI-NI(-)(*)), and the total RP population decays with approximately 10 ns lifetime at 140 K, which

112 entials and quantitative recordings of their decay with averaging at multiple sites during propagatio

113 at cytoplasmic WHx has a short half-life and decays with bimodal kinetics (approximately 20 min and 3

114 mulation, macroscopic NMDA receptor currents decay with biphasic kinetics that is believed to reflect

115 ore, while the nonaccelerated electric field decay with both Tat transport and the constitutive Tat c

116 ge excess of H2O2, this intermediate rapidly decays with both a zero- and first-order dependence on t

117 the cell-surface transporter density (n) may decay with cell radius (r) following the power rule n ~

118 d vessel status were associated with ASPECTS decay, with collateral blood vessel status demonstrating

119 All clusters exhibited p-state population decay with concomitant s-state repopulation (internal co

120 ermediate formed quickly (53 s(-1)) and then decayed with concurrent buildup of ferric iNOSoxy.

121 This method implements weight decay with conjugate gradient training and yields more s

122 and Roquin A- and B-sites jointly steer mRNA decay with context-encoded specificity, and we suggest p

123 results show that forward velocities rapidly decay with decreasing Re for all bell shapes when Re<10.

124 However, this signaling decayed with degradation of CD33.

125 nts of the phthalimide-N-oxyl radicals' self-decay with different electron-withdrawing or -donor subs

126 epidemics exists across the entire state and decay with distance (regional correlation=62%).

127 Typical interactions decay with distance and thus produce a network of connec

128 ronic coupling decreases and the exponential decay with distance becomes faster.

129 sopotential maps showed a steeper pattern of decay with distance from the electrode in scars compared

130 urrents in the apical shaft whose amplitudes decay with distance from the soma.

131 A marked exponential decay with distance was observed in the case of excitato

132 assumption that it describes an exponential decay with distance.

133 interaction probability is known to rapidly decay with distance.

134 ion of transcription factor occupancies that decay with distance; distal coordination is also observe

135 oked changes in cGMP and Ca2+ concentrations decayed with distance from a site of steady focal activa

136 esent and revealed a small vasodilation that decayed with distance.

137 the dynamics of neighboring populations that decays with distance between patches.

138 ch a steady state in which the concentration decays with distance from the source of production.

139 remium is largest for lakefront property and decays with distance from the waterbody.

140 The rate at which genetic similarity decays with distance is often spatially heterogeneous du

141 r pairs, which is high for close markers and decays with distance.

142 cifically, the extent of genomic parallelism decays with divergence in climatic conditions (that is,

143 om the increase in the amplitude of the fast decay with Dns-C6-Cho concentration with preincubation t

144 n clay surfaces follows a double exponential decay with e-folding lengths of 2.3 and 7.5 angstrom.

145 uring the exploration of a novel context and decayed with experience.

146 ibitory postsynaptic currents and potentials decayed with exponential time constants of 2.6 and 5.9 m

147 Two-long-terminal repeat (2LTR) circles decay with fast and slow phases paralleling intact provi

148 iles were obtained showing a monoexponential decay with fast fluorescence lifetimes (~0.118 ns), as p

149 neous component, the FFCFs are biexponential decays with fast and slow time components of approximate

150 The hydroquinone decays with first order kinetics or pseudo first order k

151 This intermediate decays with first-order kinetics.

152 ose H(2)O(2), as occurs with 2(T252A)-a, but decays with formation of the epoxide of b.

153 exact exchange energy density for a density decaying with Gaussian-like behavior at long range.

154 Linkage-disequilibrium decay with genomic distance was less rapid in both the w

155 Beta-scale overlap decays with geographic distance fastest in the temperate

156 tance'-a phenomenon where genetic similarity decays with geographic distance.

157 The NR1 subunit showed a biphasic decay with half-lives of 2 and 34 h for the rapidly and

158 arming maximizes near the surface, gradually decays with height, and disappears in the upper troposph

159 y castrated rat were identified; their mRNAs decayed with identical kinetics.

160 The magnitude of coherence showed power law decay with increasing distance from the microelectrode a

161 the experiments and indicated an exponential decay with increasing distance to the anterior surface.

162 The data also suggest community similarities decay with increasing geographic distance.

163 oxidized wires exhibit reversed conductance decay with increasing length, consistent with the expect

164 ribution does not follow a clear exponential decay with increasing number of thiophene units in the c

165 normalization coefficients display algebraic decay with increasing resolution and that the parameter

166 f the decline in the rate constant of [Ca2+] decay with increasing stimulation duration as an index o

167 e first encounters with a given stimulus and decay with increasing stimulus repetitions.

168 ent London dispersion forces, (ii) viscosity decay with increasing temperature reflects electron clou

169 ce of stimulation, and correlation magnitude decayed with increasing distance between recording sites

170 For most of the populations, pairwise LD decayed with increasing physical distance between loci i

171 ally with increasing donor age and decreased decaying with increasing recipient age.

172 e zone (<30 mum) where the hyperpolarization decays with increasing cell-electrode distance.

173 rrounding voxels depends on cluster size and decays with increasing distance.

174 LD in hybrids decays with increasing number of backcross generations a

175 eriodicity of approximately 10 basepairs and decays with increasing protein-protein distance.

176 mplexes making plus stands was also found to decay with inhibition of translation.

177 rm to a distance rule reflecting exponential decay with interareal separation.

178 the formation of 1 followed by a first-order decay with k(2) = 8.8 +/- 0.1 s(-1).

179 nce of benzaldehyde, the 348 nm intermediate decays, with k = 0.7 s(-1), to form a quasistable quinon

180 the dead time of the instrument, which then decays, with k = 210 s(-1), to form a transient intermed

181 rn U.S. wildfires confirm rapid levoglucosan decay with kinetics consistent with laboratory results.

182 stable as purified in dodecyl maltoside but decays with kinetics that require a double-exponential f

183 is recovers the positive correlation of mRNA decay with known AU-rich mRNA motifs, but we also uncove

184 -to-peak followed by a approximately 40 msec decay, with large spike counts (5.2 spikes per stimulus)

185 ng 20 nm under low bias, with no discernible decay with length.

186 Single-molecule conductance normally decays with length and is typically far below the theore

187 pen" state, characterized by monoexponential decay with lifetime approximately that of the free nucle

188 a single tryptophan, showed a biexponential decay with lifetimes of 4.33 and 17 ms, in contrast to p

189 e diazo compounds were detected and found to decay with lifetimes of less than 300 fs.

190 04-0.24, and triple exponential fluorescence decays with lifetimes of 4.4-6.6, 1.4-3.2, and 0.2-1.0 n

191 activity powered by short-lived radioactive decay, with limited fluid flow and little elemental frac

192 olesterol, and we noted an increase in tooth decay with longer periods of breastfeeding.

193 A, subsequently leading to nonsense mediated decay, with loss of functional protein.

194 c activity of a single rhodopsin molecule to decay with low variability.

195 able quantum yield and a simple fluorescence decay, with marginal amounts of dark species.

196 Rrp47 each contribute to Mtr4-dependent RNA decay, with maximal Mtr4-dependent decay observed with b

197 tration of (177)Lu-pentixather and afterward decayed with mean effective half-lives of 41 +/- 10 h (r

198 tration of (177)Lu-pentixather and afterward decayed with mean effective half-lives of 41 10 h (range

199 oxidative Mn(3+) species at sites of active decay, with Mn eventually accumulating as insoluble Mn(3

200 ugging forces: AJs and tugging force grew or decayed with myosin activation or inhibition, respective

201 degrees C for 20 min) and by comparing this decay with non-fire-associated fungi.

202 Unlike excitons, trions can radiatively decay with non-zero momentum by kicking out an electron,

203 ion, there was a differential rate in signal decay, with only half of the regions continuing to demon

204 assembly provides a means to coordinate mRNA decay with other cellular processes essential for growth

205 these deficiencies also cause mitochondrial decay with oxidant leakage and cellular aging and are as

206 occurrence of long linkage blocks and low LD decay with physical distance between SNPs (LD half decay

207 , across all candidate genes, showed a rapid decay with physical distance.

208 n step with pK(a) of 4.6, while C formed and decayed with pK(a)s of 6.8 and 8.2, respectively.

209 ing of the QD's interior for hindering Auger decay with postsynthetic charging for suppressing parasi

210 s the additional advantage of energetic beta decay with potential therapeutic efficacy.

211 B)-nitrosyl) transient dinitrosyl complex to decay with production of N2O at a rate of 0.7 s(-1) at 4

212 the entanglement in the angle-OAM bases also decays with propagation, and after a few centimeters of

213 ciation of C3bBb complexes, because blocking decay with properdin and C3 nephritic factor did not res

214 up dental plaque and a vaccine against tooth decay with questionable potential for widespread applica

215 single-copy assay data revealed 3 phases of decay with RAL-containing ART, with a longer duration of

216 scan peaked within approximately 1 msec and decayed with rapid (tau(1) of 1.7 msec) and slow compone

217 e and magnesium, which undergoes first-order decay with rate constants independent of the concentrati

218 trast to previous reports of a biexponential decay with rates of 0.2 and 0.9 ms.

219 The transient intermediates decayed with rates of 80,000 s-1 and 11,000 s-1 in the p

220 mV were followed by three phases of [Ca2+]i decay with repolarization to both -110 and -50 mV.

221 at burst cells, whereas their activity level decays with residual gaze error.

222 eumelanin precursor 5,6-dihydroxyindole (1) decays with second-order kinetics to generate broad visi

223 distinct CXCR4 or CCR5 coreceptor phenotypes decayed with similar rates.

224 r supporting this proposal, each acetylation decays with similar kinetics when Htz1 transcription is

225 >/= 2 aftershocks showed a uniform power-law decay with slope -1.35 out to 50 km from the mainshocks.

226 ecays or acquiring the I(VV)(t) and I(VH)(t) decays with static polarizers before fitting them global

227 in these subjects lead to nonsense-mediated decay with subsequent reduction of RNA expression and pr

228 converted to a NMR observable triplet state decaying with T(1), in the order of seconds.

229 We found ALT decays with t(1/2) = 12.7 hours.

230 proviral DNA assay, confirmed that reservoir decay with t1/2 of 44 months did not continue with long-

231 NIR) luminescence exhibits a monoexponential decay with tau = 2.4 ns in the solid state and 1 ns in l

232 au(1) = 3 ps time constant and excited state decay with tau(1) = 3 ps, tau(2) = 14 ps, and tau(3) = 1

233 ve comparison of the rates of Q(A)(-) and Z* decay with the decay of the 1478 cm(-1) line supported t

234 h and its inductive and resonance components decay with the increase in spacer length, its weakening

235 ion are strongly localized and exponentially decay with the network distance away from the perturbed

236 The energy requirements exponentially decay with the number of target nodes, suggesting that l

237 Trp fluorescence decay with the onset of solvation dynamics of the chromo

238 spontaneous spin coherences that precess and decay with the same characteristic energy and timescales

239 It produces 5 alpha-particles through its decay, with the clinically approved (223)Ra as its first

240 d versus time follow variants of exponential decay, with the flux equal to the decay rate multiplied

241 er 250 ms can be fit to a double exponential decay, with the intensity of the fast component roughly

242 bstituted nitrophenols showed an exponential decay, with the nitro-group on the aromatic ring found t

243 nd miRNAs work together to affect transcript decay, with the rescue of miRNA recognition sites via RB

244 ng positive covariation in laying dates that decayed with the distance between breeding sites, sugges

245 The batho/bsi mixtures decayed with the following reaction scheme: batho/bsi <=

246 ption appears on an ultrafast time scale and decays with the electron population, irrespective of the

247 pin-coated films show faster non-exponential decays with the slowest component of the crystal PL abse

248 dence that viral evolutionary rate estimates decay with their measurement timescales and that the rat

249 eval probability of memories that gracefully decays with their age.

250 zzle because magnetic fields are expected to decay with time but a cool surface suggests that the sta

251 eals changes that are fit by a biexponential decay with time constants of 2.4 +/- 0.2 and 36 +/- 0.2

252 as well approximated by a double exponential decay with time constants of 6-17 s and 2-3 min.

253 uptly decreased, followed by a biexponential decay with time constants of approximately 4 and 200 ms.

254 In ASCT2, these currents show biphasic decay with time constants, tau, in the 1-30 ms time rang

255 n and across individuals, showed the typical decay with time elapsed between encoding and testing, we

256 Relationship of rates of decay with time to worsening and eccentricity and agreem

257 e absence of the hippocampus, these memories decay with time, lacking the permanence that is a hallma

258 gree of oxidation of MXenes to exponentially decay with time, which is consistent with the oxidation

259 trend (increasing/decreasing) or exponential decay with time.

260 release permeability predicts an exponential decay with time.

261 The isolated glycinergic IPSC decayed with time constants of 7.8+/-0.3 and 38.3+/-1.7

262 The H2O2 gradually decayed with time due to the diffusion of H2O2-scavengin

263 ) and C(14) filtrates to elevate [Ca(2+)](i) decayed with time was consistent with this hypothesis.

264 rate that was modulated by an annual cycle, decaying with time.

265 n rates, seismic activity in the zone is not decaying with time.

266 Activity of FXase decays with time and reflects the lability of FVIIIa.

267 nent designated X-685 peaking at 685 nm that decays with time constants of 0.28 and 5.8 ns and does n

268 lambdamax= 510 nm that first grows and then decays with time constants of 63 and 270 ns, respectivel

269 object's distance from the current focus and decays with time elapsed in the narrative since the item

270 nstrate that the production rate of deposits decays with time following a power law whose exponent li

271 le the linear response signal oscillates and decays with time like [Formula: see text], the amplitude

272 at the cation-electron ion pair subsequently decays with time scales that match the fluorescence life

273 The KPLO mission's orbital altitude decays with time to comprehensively sample the lunar mag

274 to which microbiome composition is heritable decays with time, and selection can only act at the holo

275 However, the electrostatic charge decays with time, especially in humid conditions.

276 es include trials where the treatment effect decays with time, immunotherapy trials where treatment e

277 ined helix fractions defined monoexponential decays, with time-constants of approximately 120 ns, ind

278 or their binding to Bach2 mRNA to couple its decay with translation to restrain the magnitude and dur

279 The anisotropy decayed with two correlation times near 5 and 370 ns, wi

280 illion years but follow a similar pattern of decay, with ultimately only 1.4% of chimeras preserved.

281 These transient IR bands decay with virtually identical lifetimes to those observ

282 umans, many promoters appear to be gradually decaying with weak transcriptional output and relaxed se

283 ate relaxation exhibiting a multiexponential decay with well-defined rate constants.