| 释义 |
persistent, a.|pəˈsɪstənt|
[ad. L. persistent-em, pr. pple. of persistĕre to persist. In F. persistant; cf. persistence.]
1. Persisting or continuing firmly in some action, course, or pursuit, esp. against opposition or remonstrance, or in spite of failure.
1830Herschel Stud. Nat. Phil. 81 Our resistance against the destruction of..prejudices..of sense, is commonly more violent at first, but less persistent, than in the case of those of opinion. 1868E. Edwards Ralegh I. xvi. 332 His greed, no less than his ambition,..made him a persistent colonizer. 1888F. Hume Mme. Midas i. i, Her suitors were numerous and persistent as those of Penelope.
2. Existing continuously in time; enduring.
1853Kane Grinnell Exp. xxxix. (1856) 360 There is a something about this persistent day antagonistic to sleep. 1864H. Spencer Biol. I. iii. viii. §144. 404 This assumption of a persistent formative power, inherent in organisms, and making them unfold into higher forms. 1866Tate Brit. Mollusks iv. 169 A marked and persistent variety. 1871L. Stephen Playgr. Eur. iv. (1894) 94 A persistent screen of stormy cloud drove up the valley.
b. Of an action or condition: Continued, continuous, constant; constantly repeated.
1857G. Bird's Urin. Deposits 289 The persistent occurrence of deposits of the earthy phosphates in the urine. 1872Huxley Phys. iv. 100 The persistent breathing of such air tends to lower all kinds of vital energy.
3. spec.
a. Zool. and Bot. Of parts of animals and plants (as the horns, hair, leaves, calyces, etc.): Remaining after the period at which such parts in other cases fall off or wither; permanent; continuing; opp. to deciduous or caducous.
1826Kirby & Sp. Entomol. IV. 344 Persistent... Legs which the insect has in all its states. Ex. The legs attached to the trunk. 1830Lindley Nat. Syst. Bot. 206 Crowned by the persistent lobes of the calyx. 1835Kirby Hab. & Inst. Anim. II. xxiv. 502 Lastly, come the Ruminants, whose horns are hollow and naked, but persistent. 1872Oliver Elem. Bot. ii. 199 Called ‘Everlastings’ from their dry, scarious, persistent involucres. 1880Gray Struct. Bot. iii. (ed. 6) 86 Leaves..may be..persistent, when they remain through the cold season..during which vegetation is interrupted. 1888Rolleston & Jackson Anim. Life 348 In some Mammalia the teeth grow from persistent pulps.
b. Geol. Of a stratum: Extending continuously over the whole area occupied by the formation; not thinning out or disappearing.
1833Lyell Princ. Geol. III. 173 The individual strata are rarely persistent for a great distance. 1839Murchison Silur. Syst. i. xxix. 372 The bed is persistent only for a few yards. 1865Geikie Scen. & Geol. Scot. vi. 138 Even with such doubtful forms, the two main systems remain tolerably persistent.
Hence perˈsistently adv., in a persistent manner, with persistence or continuously repeated action.
1859Smiles Self-Help 323 Gentleness in society..pushes its way quietly and persistently. 1880C. R. Markham Peruv. Bark iii. 276 A fair recompense has been persistently refused.
Add:[3.] c. Ecol. That remains within an environment for a long period of time: applied esp. to chemically unreactive pollutants, and occas. to radioactivity having a long half-life.
1952Oklahoma Agric. Exper. Station Bull. No. T42. p. 9 Toxaphene was the most persistent of the three insecticides studied, parathion was somewhat less stable, and methoxychlor the least permanent. 1955Bull. Atomic Sci. Jan. 5/1 The long-range genetic danger of exposure..to low-level, but widespread and persistent radioactivity..is only beginning to be dimly perceived. 1963[see radiological a. b]. 1970[see lindane n.]. 1987Financial Rev. (Sydney) 21 Aug. 5/1 Before May 25 this year, farmers keen to produce the best potatoes bought chemicals, ‘persistent’ organochlorines such as heptachlor, to kill bugs.
Add:[2.] c. Path. persistent vegetative state, a condition of indefinite duration resulting from brain damage, in which a patient recovering from a coma retains brainstem functions such as reflex responses and may appear wakeful, but has no cognitive functions or other evidence of cerebral cortical activity. Abbrev. PVS s.v. *P II. a.
1972Lancet 1 Apr. 734/1 Patients with severe brain damage due to trauma..may now survive indefinitely... Such patients are best described as in a persistent vegetative state. 1987Oxf. Textbk. Med. (ed. 2) II. xxi. 51/1 The question of whether it is appropriate to provide the nutrition and nursing care required to ensure survival once the persistent vegetative state has been diagnosed is now a topic of debate. 1993U.S. News & World Rep. 18 Jan. 78/3 In 1986, at the age of 60, she suffered bleeding on the brain and went into a ‘persistent vegetative state’—alive but with essentially no higher brain function. |