In Finland, under nursery conditions hybrid aspen may continue their shoot growth until early September. Thus, frost hardening is usually delayed. To solve this problem, we used a three-week period of short-day （SD）...In Finland, under nursery conditions hybrid aspen may continue their shoot growth until early September. Thus, frost hardening is usually delayed. To solve this problem, we used a three-week period of short-day （SD） treatment between late July and mid-August. During autumn after frost exposure, frost hardiness （FH） was assessed three times with a stem-browning test. The resuits showed that after SD treatment shoot growth ceased and FH increased when compared to untreated hybrid aspen. Furthermore, the height of SD-treated hybrid aspen varied much less than that of the control plants. We conclude that SD treatment in the nursery during the growing period can be used as a supplementary method for producing well-hardened and uniform hybrid aspen plants.展开更多
Aims Nursery and forest operations require that frost hardiness results be produced faster than can be provided by controlled freezing tests.There is a great challenge to develop a rapid method for predicting frost ha...Aims Nursery and forest operations require that frost hardiness results be produced faster than can be provided by controlled freezing tests.There is a great challenge to develop a rapid method for predicting frost hardiness that might not necessitate controlled freezing tests.The aim of this study was to examine the assessment of the frost hardiness of shoots and needles of Pinus bungeana by electrical impedance spectroscopy(EIS)with and without controlled exposure to freezing.Methods The frost hardiness of current-year shoots and needles of P.bungeana in an 8-year-old provenance field trial was measured at Shisanlin Nursery in Beijing,China,from September 2006 to January 2007 by means of EIS and conventional electrolyte leakage(EL).In the same plants,but without controlled freezing test,were monitored the EIS parameters in current-year shoots and needles.Important Findings The results showed that(i)after controlled freezing tests,the frost hardiness estimated by EIS parameters(extracellular resistance,re,and membrane time constant,sm)was significantly correlated with the frost hardiness assessed by EL method(r=0.95)and(ii)for the samples not exposed to controlled freezing treatment,the relaxation time s1 for shoots and b for needles had greater correlations with the frost hardiness estimated by EL after controlled freezing tests relative to the other parameters(r=0.90 for shoots and r=0.84 for needles,respectively).The parameters re of shoots and needles and sm of needles might be applied for measuring frost hardiness of samples after exposed to controlled freezing tests.The frost hardiness results can be obtained within 48 h.The parameters s1 of shoots and b of needles could be used for estimating the frost hardiness of samples without using a controlled freezing test.The frost hardiness results can be obtained within 24 h.展开更多
Asian corn borer, Ostrinia furnacalis （Guenee）, is a key corn pest in the Asian-Western Pacific countries. It overwinters as flail-grown larvae in plant stalks or in a spun-silk covering located in the plant debris ...Asian corn borer, Ostrinia furnacalis （Guenee）, is a key corn pest in the Asian-Western Pacific countries. It overwinters as flail-grown larvae in plant stalks or in a spun-silk covering located in the plant debris in the temperate regions of China. Supercooling point （SCP） and survival rate after low sub-zero temperature treatment were assessed for field-collected populations in the laboratory using a cool bath with a 1 ℃/min cooling rate until -40℃. Mean SCPs were varied among geographical populations, with a significant decline from -22.7℃ of Haikou, the multivoltine tropical population in the south, to -28.5℃ of Gongzhuling, the univoltine temperate population in the northeast of China. In addition, there was more than 1℃ difference in SCP between Gongzhuling univoltine and bivoltine populations that were from the same geographic origin. Mean SCPs of the Guangzhou population fluctuated over the year, with significantly lower SCPs in winter than in other seasons, which correlated with a significantly higher proportion of diapausing larvae in winter than in other seasons. Over 41% of overwintering larvae from the northeast population could withstand to be supercooled for a few minutes to the low sub-zero temperature of-40℃, but only 6.7% of their southern counterparts did so. The findings from this study suggest that O. furnacalis mostly takes advantage of freeze avoidance as diapausing larvae for overwintering in the southern region, whereas it exhibits freeze tolerance in diapause in the northeastern region.展开更多
In this article,we investigate the(big) Hankel operator H_(f) on the Hardy spaces of bounded strongly pseudoconvex domains Ω in C^(n).We observe that H_(f )is bounded on H~p(Ω)(1 <p <∞) if f belongs to BMO an...In this article,we investigate the(big) Hankel operator H_(f) on the Hardy spaces of bounded strongly pseudoconvex domains Ω in C^(n).We observe that H_(f )is bounded on H~p(Ω)(1 <p <∞) if f belongs to BMO and we obtain some characterizations for Hf on H~2(Ω) of other pseudoconvex domains.In these arguments,Amar's L~p-estimations and Berndtsson's L^(2)-estimations for solutions of the ■_(b)-equation play a crucial role.In addition,we solve Gleason's problem for Hardy spaces H~p(Ω)(1 ≤p≤∞) of bounded strongly pseudoconvex domains.展开更多
Though atomic decomposition is a very useful tool for studying the boundedness on Hardy spaces for some sublinear operators,untill now,the boundedness of operators on weighted Hardy spaces in a multi-parameter setting...Though atomic decomposition is a very useful tool for studying the boundedness on Hardy spaces for some sublinear operators,untill now,the boundedness of operators on weighted Hardy spaces in a multi-parameter setting has been established only by almost orthogonality estimates.In this paper,we mainly establish the boundedness on weighted multi-parameter local Hardy spaces via atomic decomposition.展开更多
Assume that L is a non-negative self-adjoint operator on L^(2)(ℝ^(n))with its heat kernels satisfying the so-called Gaussian upper bound estimate and that X is a ball quasi-Banach function space onℝ^(n) satisfying som...Assume that L is a non-negative self-adjoint operator on L^(2)(ℝ^(n))with its heat kernels satisfying the so-called Gaussian upper bound estimate and that X is a ball quasi-Banach function space onℝ^(n) satisfying some mild assumptions.Let HX,L(ℝ^(n))be the Hardy space associated with both X and L,which is defined by the Lusin area function related to the semigroup generated by L.In this article,the authors establish various maximal function characterizations of the Hardy space HX,L(ℝ^(n))and then apply these characterizations to obtain the solvability of the related Cauchy problem.These results have a wide range of generality and,in particular,the specific spaces X to which these results can be applied include the weighted space,the variable space,the mixed-norm space,the Orlicz space,the Orlicz-slice space,and the Morrey space.Moreover,the obtained maximal function characterizations of the mixed-norm Hardy space,the Orlicz-slice Hardy space,and the Morrey-Hardy space associated with L are completely new.展开更多
This paper is devoted to studying the behaviors of the fractional type Marcinkiewicz integralsμΩ,βand the commutatorsμΩ,βb generated byμΩ,βwith b b∈Lloc(Rn)on weighted Hardy spaces.Under the assumption of th...This paper is devoted to studying the behaviors of the fractional type Marcinkiewicz integralsμΩ,βand the commutatorsμΩ,βb generated byμΩ,βwith b b∈Lloc(Rn)on weighted Hardy spaces.Under the assumption of that the homogeneous kernelΩsatisfies certain regularities,the authors obtain the boundedness ofμΩ,βfrom the weighted Hardy spaces Hωpp(Rn)to the weighted Lebesgue spaces Lωqq(Rn)for n/(n+β)≤<p≤1 with 1/q=1/p-β/n,as well as the same(Hωpp,Lωqq)-boudedness ofμΩ,βb when b belongs to BMOωp,p(Rn),which is a non-trivial subspace of BMO(Rn).展开更多
Letμbe a positive Borel measure on the interval[0,1).The Hankel matrixHμ=(μn,k)n,k≥0 with entries μn,k=μn+k,whereμn=∫[0,1)tndμ(t),induces formally the operator asDHμ(f)(z)=∞∑n=0(∞∑k=0 μn,kak)z^(n),z∈D,...Letμbe a positive Borel measure on the interval[0,1).The Hankel matrixHμ=(μn,k)n,k≥0 with entries μn,k=μn+k,whereμn=∫[0,1)tndμ(t),induces formally the operator asDHμ(f)(z)=∞∑n=0(∞∑k=0 μn,kak)z^(n),z∈D,where f(z)=∞∑n=0a_(n)z^(n) is an analytic function in D.We characterize the positive Borel measures on[0,1)such thatDHμ(f)(z)=f[0,1)f(t)/(1-tz)^(2)dμ(t) for all f in the Hardy spaces Hp(0<p<∞),and among these we describe those for which is a bounded(resp.,compact)operator from Hp(0<p<∞)into Hq(q>p and q≥1).We also study the analogous problem in the Hardy spaces H^(p)(1≤p≤2).展开更多
In this paper,we investigate the complex symmetric structure of Toeplitz operators T_(φ)on the Hardy space over the bidisk.We first characterize the weighted composition operators,W_(u,v)which are J-symmetric and uni...In this paper,we investigate the complex symmetric structure of Toeplitz operators T_(φ)on the Hardy space over the bidisk.We first characterize the weighted composition operators,W_(u,v)which are J-symmetric and unitary.As a consequence,we characterize conjugations of the form A_(u,v).In addition,a class of conjugations of the form C_(λ,a)is introduced.We show that the class of conjugations C_(λ,a)coincides with the class of conjugations A_(u,v);we then characterize the complex symmetry of the Toeplitz operators T_(φ)with respect to the conjugation C_(λ,a).展开更多
文摘In Finland, under nursery conditions hybrid aspen may continue their shoot growth until early September. Thus, frost hardening is usually delayed. To solve this problem, we used a three-week period of short-day （SD） treatment between late July and mid-August. During autumn after frost exposure, frost hardiness （FH） was assessed three times with a stem-browning test. The resuits showed that after SD treatment shoot growth ceased and FH increased when compared to untreated hybrid aspen. Furthermore, the height of SD-treated hybrid aspen varied much less than that of the control plants. We conclude that SD treatment in the nursery during the growing period can be used as a supplementary method for producing well-hardened and uniform hybrid aspen plants.
基金National Natural Science Foundation of China(grant number 30640035)the Scientific Research Foundation for the Returned Overseas Scholars,Agricultural University of Hebei(grant number 200406).
文摘Aims Nursery and forest operations require that frost hardiness results be produced faster than can be provided by controlled freezing tests.There is a great challenge to develop a rapid method for predicting frost hardiness that might not necessitate controlled freezing tests.The aim of this study was to examine the assessment of the frost hardiness of shoots and needles of Pinus bungeana by electrical impedance spectroscopy(EIS)with and without controlled exposure to freezing.Methods The frost hardiness of current-year shoots and needles of P.bungeana in an 8-year-old provenance field trial was measured at Shisanlin Nursery in Beijing,China,from September 2006 to January 2007 by means of EIS and conventional electrolyte leakage(EL).In the same plants,but without controlled freezing test,were monitored the EIS parameters in current-year shoots and needles.Important Findings The results showed that(i)after controlled freezing tests,the frost hardiness estimated by EIS parameters(extracellular resistance,re,and membrane time constant,sm)was significantly correlated with the frost hardiness assessed by EL method(r=0.95)and(ii)for the samples not exposed to controlled freezing treatment,the relaxation time s1 for shoots and b for needles had greater correlations with the frost hardiness estimated by EL after controlled freezing tests relative to the other parameters(r=0.90 for shoots and r=0.84 for needles,respectively).The parameters re of shoots and needles and sm of needles might be applied for measuring frost hardiness of samples after exposed to controlled freezing tests.The frost hardiness results can be obtained within 48 h.The parameters s1 of shoots and b of needles could be used for estimating the frost hardiness of samples without using a controlled freezing test.The frost hardiness results can be obtained within 24 h.
文摘Asian corn borer, Ostrinia furnacalis （Guenee）, is a key corn pest in the Asian-Western Pacific countries. It overwinters as flail-grown larvae in plant stalks or in a spun-silk covering located in the plant debris in the temperate regions of China. Supercooling point （SCP） and survival rate after low sub-zero temperature treatment were assessed for field-collected populations in the laboratory using a cool bath with a 1 ℃/min cooling rate until -40℃. Mean SCPs were varied among geographical populations, with a significant decline from -22.7℃ of Haikou, the multivoltine tropical population in the south, to -28.5℃ of Gongzhuling, the univoltine temperate population in the northeast of China. In addition, there was more than 1℃ difference in SCP between Gongzhuling univoltine and bivoltine populations that were from the same geographic origin. Mean SCPs of the Guangzhou population fluctuated over the year, with significantly lower SCPs in winter than in other seasons, which correlated with a significantly higher proportion of diapausing larvae in winter than in other seasons. Over 41% of overwintering larvae from the northeast population could withstand to be supercooled for a few minutes to the low sub-zero temperature of-40℃, but only 6.7% of their southern counterparts did so. The findings from this study suggest that O. furnacalis mostly takes advantage of freeze avoidance as diapausing larvae for overwintering in the southern region, whereas it exhibits freeze tolerance in diapause in the northeastern region.
基金supported by the National Natural Science Foundation of China(12271101)。
文摘In this article,we investigate the(big) Hankel operator H_(f) on the Hardy spaces of bounded strongly pseudoconvex domains Ω in C^(n).We observe that H_(f )is bounded on H~p(Ω)(1 <p <∞) if f belongs to BMO and we obtain some characterizations for Hf on H~2(Ω) of other pseudoconvex domains.In these arguments,Amar's L~p-estimations and Berndtsson's L^(2)-estimations for solutions of the ■_(b)-equation play a crucial role.In addition,we solve Gleason's problem for Hardy spaces H~p(Ω)(1 ≤p≤∞) of bounded strongly pseudoconvex domains.
文摘Though atomic decomposition is a very useful tool for studying the boundedness on Hardy spaces for some sublinear operators,untill now,the boundedness of operators on weighted Hardy spaces in a multi-parameter setting has been established only by almost orthogonality estimates.In this paper,we mainly establish the boundedness on weighted multi-parameter local Hardy spaces via atomic decomposition.
基金supported by the National Key Research and Development Program of China(2020YFA0712900)the National Natural Science Foundation of China(12371093,12071197,12122102 and 12071431)+2 种基金the Key Project of Gansu Provincial National Science Foundation(23JRRA1022)the Fundamental Research Funds for the Central Universities(2233300008 and lzujbky-2021-ey18)the Innovative Groups of Basic Research in Gansu Province(22JR5RA391).
文摘Assume that L is a non-negative self-adjoint operator on L^(2)(ℝ^(n))with its heat kernels satisfying the so-called Gaussian upper bound estimate and that X is a ball quasi-Banach function space onℝ^(n) satisfying some mild assumptions.Let HX,L(ℝ^(n))be the Hardy space associated with both X and L,which is defined by the Lusin area function related to the semigroup generated by L.In this article,the authors establish various maximal function characterizations of the Hardy space HX,L(ℝ^(n))and then apply these characterizations to obtain the solvability of the related Cauchy problem.These results have a wide range of generality and,in particular,the specific spaces X to which these results can be applied include the weighted space,the variable space,the mixed-norm space,the Orlicz space,the Orlicz-slice space,and the Morrey space.Moreover,the obtained maximal function characterizations of the mixed-norm Hardy space,the Orlicz-slice Hardy space,and the Morrey-Hardy space associated with L are completely new.
文摘This paper is devoted to studying the behaviors of the fractional type Marcinkiewicz integralsμΩ,βand the commutatorsμΩ,βb generated byμΩ,βwith b b∈Lloc(Rn)on weighted Hardy spaces.Under the assumption of that the homogeneous kernelΩsatisfies certain regularities,the authors obtain the boundedness ofμΩ,βfrom the weighted Hardy spaces Hωpp(Rn)to the weighted Lebesgue spaces Lωqq(Rn)for n/(n+β)≤<p≤1 with 1/q=1/p-β/n,as well as the same(Hωpp,Lωqq)-boudedness ofμΩ,βb when b belongs to BMOωp,p(Rn),which is a non-trivial subspace of BMO(Rn).
基金supported by the Zhejiang Provincial Natural Science Foundation (LY23A010003)the National Natural Science Foundation of China (11671357).
文摘Letμbe a positive Borel measure on the interval[0,1).The Hankel matrixHμ=(μn,k)n,k≥0 with entries μn,k=μn+k,whereμn=∫[0,1)tndμ(t),induces formally the operator asDHμ(f)(z)=∞∑n=0(∞∑k=0 μn,kak)z^(n),z∈D,where f(z)=∞∑n=0a_(n)z^(n) is an analytic function in D.We characterize the positive Borel measures on[0,1)such thatDHμ(f)(z)=f[0,1)f(t)/(1-tz)^(2)dμ(t) for all f in the Hardy spaces Hp(0<p<∞),and among these we describe those for which is a bounded(resp.,compact)operator from Hp(0<p<∞)into Hq(q>p and q≥1).We also study the analogous problem in the Hardy spaces H^(p)(1≤p≤2).
基金partially the National Natural Science Foundation of China(11771340,12101179,12171373)。
文摘In this paper,we investigate the complex symmetric structure of Toeplitz operators T_(φ)on the Hardy space over the bidisk.We first characterize the weighted composition operators,W_(u,v)which are J-symmetric and unitary.As a consequence,we characterize conjugations of the form A_(u,v).In addition,a class of conjugations of the form C_(λ,a)is introduced.We show that the class of conjugations C_(λ,a)coincides with the class of conjugations A_(u,v);we then characterize the complex symmetry of the Toeplitz operators T_(φ)with respect to the conjugation C_(λ,a).
