Higher ramification and varieties of secant divisors on the generic curve

For a smooth projective curve, the cycles of e-secant k-planes are among the most studied objects in classical enumerative geometry and there are well-known formulas due to Castelnuovo, Cayley and MacDonald concerning them. Despite various attempts, surprisingly little is known about the enumerative validity of such formulas. The aim of this paper is to completely clarify this problem in the case of the generic curve C of given genus. Using degeneration techniques and a few facts about the birational geometry of moduli spaces of stable pointed curves we determine precisely under which conditions the cycle of e-secant k-planes in non-empty and we compute its dimension. We also precisely determine the dimension of the variety of linear series on C carrying e-secant k-planes. In a different direction, in the last part of the paper we study the distribution of ramification points of the powers of a line bundle on C having prescribed ramification at a given point.Comment: 25 pages. Numerous changes suggested by the referee, several proofs explained in more detail. To appear in the Journal of the London Mathematical Societ

The dynamical distance and intrinsic structure of the globular cluster omega Centauri

We determine the dynamical distance D, inclination i, mass-to-light ratio M/L and the intrinsic orbital structure of the globular cluster omega Cen, by fitting axisymmetric dynamical models to the ground-based proper motions of van Leeuwen et al. and line-of-sight velocities from four independent data-sets. We correct the observed velocities for perspective rotation caused by the space motion of the cluster, and show that the residual solid-body rotation component in the proper motions can be taken out without any modelling other than assuming axisymmetry. This also provides a tight constraint on D tan i. Application of our axisymmetric implementation of Schwarzschild's orbit superposition method to omega Cen reveals no dynamical evidence for a significant radial dependence of M/L. The best-fit dynamical model has a stellar V-band mass-to-light ratio M/L_V = 2.5 +/- 0.1 M_sun/L_sun and an inclination i = 50 +/- 4 degrees, which corresponds to an average intrinsic axial ratio of 0.78 +/- 0.03. The best-fit dynamical distance D = 4.8 +/- 0.3 kpc (distance modulus 13.75 +/- 0.13 mag) is significantly larger than obtained by means of simple spherical or constant-anisotropy axisymmetric dynamical models, and is consistent with the canonical value 5.0 +/- 0.2 kpc obtained by photometric methods. The total mass of the cluster is (2.5 +/- 0.3) x 10^6 M_sun. The best-fit model is close to isotropic inside a radius of about 10 arcmin and becomes increasingly tangentially anisotropic in the outer region, which displays significant mean rotation. This phase-space structure may well be caused by the effects of the tidal field of the Milky Way. The cluster contains a separate disk-like component in the radial range between 1 and 3 arcmin, contributing about 4% to the total mass.Comment: 37 pages (23 figures), accepted for publication in A&A, abstract abridged, for PS and PDF file with full resolution figures, see http://www.strw.leidenuniv.nl/~vdven/oc

Degreening Characteristic of Musa AAA 'Berangan' and "William Cavendish' Bananas

A study was conducted on the changes in cellular structure, physiology and physiochemical of Musa AAA 'Berangan' and 'Cavendish' as the ripening progressed at 18+2 and 2722 OC. Mature green (ripening stage (RS) 1) bananas were initiated to ripen using 0.02% acetylene from calcium carbide (CaC2) source (with an equivalent of 1 g cac2.kg-' fruit) for 24 h. A hand of Berangan and Cavendish fmit was split into 2 clusters. One of the clusters was initiated and ripened at 18t2 OC RH 90- 94%, while the other was initiated and ripened at 2722 OC RH 75-80%. The experiment was conducted using randomized complete block design with four replications. Five fruits per replicate were used. The various ripening stages were evaluated with the aid of FAMA visual colour score until the fruit turned intosdl? yellow at RS 6. For the Cavendish ripened at 27+2 OC (C27) where the fruit failed to degreen, the evaluation was done daily until senescence, when brown specks appeared on the peel. Data from measurements of ripening duration, L*, C* and h0 values, chlorophyll a, b and total chlorophylls, water loss, stomatal density, stomatal length and opening, peel thickness, peel and pulp fresh and dry weight, cell length and width of photosynthetic, epidermal, crystalliferous, tanniferous and starch granules, pulp firmness, soluble solids concentration (SSC), titratable acidity and pH were analysed using analysis of variance and differences between means were determined by Duncan Multiple Range Test. Data from starch iodine test, cellular structure and ultrastructure were documented as photographs or micrographs. Berangan degreened naturally under tropical ripening temperature of 27+2 OC, and a golden yellow fruit of RS 6 was obtained within 4 d of ripening. In contrast, Cavendish failed to degreen at 27+2 OC even though the pulp had softened. By day 5 after the acetylene treatment brown specks started to appear on the fruit surface indicating senescence had commenced. Cavendish could only degreen when ripened at 1822 OC, and a yellow fruit of RS 6 was obtained after 9 d of ripening. On the contrary, Berangan could not degreen and ripen under 1822 OC thus the fruit was discarded. TEM revealed that at RS 6 the grana-thylakoid membrane of chromoplast Berangan ripened at 2722 OC (B27) and Cavendish ripened at 1852 OC (C18) had lysed. Besides, plastoglobuli increased in number, and types of staining density and vesicles increased in number and size. However at day 5 of C27, the grana-thylakoid membrane retained and this was in concurrent with the high retention of chlorophyll content in fruit peel. The total chlorophyll retained in C27 was 57%, while only 25 and 40% of total chlorophyll was retained in B27 and C18 respectively. The high retention of chlorophyll content in C27 had caused it to correlate significantly with L*, C* and h0 values. Among B27, C18 and C27, C27 encountered the most water loss. However, there was no correlation between water loss and stomata1 density and opening. The existence of cracks and pores on the banana peel surface could be the iii passage for water loss. The severe water loss caused the peel thickness of C27 to be the thinnest among the bananas studied although initially its peel was thicker than B27. The fruit pulp and peel behaved differently towards ripening temperature. The moisture content in pulp increased, while no moisture content in peel decreased as ripening progressed. This led to increase of pulp to peel fresh weight ratio and C27 had the highest ratio as compared to C18 and B27. The softening of the banana fruit was due to starch degradation and dissolution of middle lamellae. SEM revealed that the pulp starch granules decreased in size and density as ripening progressed. The blue-black stained area of starch-iodine complex cleared from the central core of fmit towards the periphery of peel in all the bananas studied. The clearing pattern was most rapid in C27. The hydrolysed starch increased the SSC of all the bananas studied but the most significant increase was in C27. The titratable acidity of the three bananas studied increased then decreased as ripening progressed. In contrast, the pH decreased then increased as contrary to the trend of titratable acidity. The tropical temperature of 2722 OC, besides failing to degreen, had caused poor keeping and eating quality of Cavendish

Kinetic analysis of copper(I)/feringa-phosphoramidite catalysed AlEt3 1,4-addition to cyclohex-2-en-1-one

ReactIR studies of mixtures of AlEt3 (A) and cyclohex-2-en-1-one (CX) in Et2O indicate immediate formation of the Lewis acid-base complex (CX.A) at -40 oC (K = 12.0 M-1, ΔGo react -1.1 kcal mol-1). Copper(I) catalysts, derived from pre-catalytic Cu(OAc)2 (up to 5 mol- %) and (R,S,S)-P(binaphtholate){N(CHMePh)2} [Feringa’s ligand (L), up to 5 mol-%] convert CX.A (0.04-0.3 M) into its 1,4-addition product enolate (E) within 2000 sec at -40 oC. Kinetic studies (ReactIR and chiral GC) of CX.A, CX and (R)-3-ethylcyclohexanone (P, the H+ quench product of enolate E) show that the true catalyst is formed in the first 300 sec and this subsequently provides P in 82% ee. This true catalyst converts CX.A to E with a rate law [Cu]1.5[L]0.66[CX.A]1 when [L]/[Cu] ≤ 3.5. Above this ligand ratio inhibition by added ligand with order [L]-2.5 is observed. A rate determining step (rds) of Cu3L2(CX.A)2 stoichiometry is shown to be most consistent with the rate law. The presence of the enolate in the active catalyst (Graphical Abstract) best accounts for the reaction’s induction period and molecularity as [E] ≡ [CX.A]. Catalysis proceeds through a ‘shuttling mechanism’ between two C2 symmetry related ground state intermediates. Each turnover consumes one equivalent of CX.A, expels one molecule of E and forms the new Cu-Et bond needed for the next cycle (Graphic Abstract). The observed ligand (L) inhibition and a non-linear ligand Lee effect on the ee of P are all well simulated by the kinetic model. DFT studies [ωB97X-D/SRSC] support coordination of CX.A to the groundstate Cu-trimer and its rapid conversion to E

Dubious effects of methadone as an "anticancer" drug on ovarian cancer cell-lines and patient-derived tumor-spheroids

Background. The opioid agonist D, L-methadone exerts analgesic effects via the mu opioid receptor, encoded by OPRM1 and therefore plays a role in chronic pain management. In preclinical tumor-models D,L-methadone shows apoptotic and chemo-sensitizing effects and was therefore hyped as an off-label "anticancer" drug without substantiation from clinical trials. Its effects in ovarian cancer (OC) are completely unexplored. Methods. We analyzed OPRM1-mRNA expression in six cisplatin-sensitive, two cisplatin-resistant OC cell-lines, 170 OC tissue samples and 12 non-neoplastic control tissues. Pro-angiogenetic, cytotoxic and apoptotic effects of D,L-methadone were evaluated in OC cell-lines and four patient-derived tumor-spheroid models. Results. OPRM1 was transcriptionally expressed in 69% of OC-tissues and in three of eight OC cell-lines. D, L-methadone exposure significantly reduced cell-viability in five OC cell-lines irrespective of OPRM1 expression. D, L-methadone, applied alone or combined with cisplatin, showed no significant effects on apoptosis or VEGF secretion in cell-lines. Notably, in two of the four sphero id models, treatment with D, L-methadone significantly enhanced cell growth (by up to 121%), especially after long-term exposure. This is consistent with the observed attenuation of the inhibitory effects of cisplatin in three spheroid models when adding D, L-methadone. The effect of methadone treatment on VEGF secretion in tumor-spheroids was inconclusive. Conclusions. Our study demonstrates that certain OC samples express OPRM1, which, however, is not a prerequisite for D, L-methadone function. As such, D,L-methadone may exert also detrimental effects by stimulating the growth of certain OC-cells and abrogating cisplatin's therapeutic effect. (C) 2022 The Authors. Published by Elsevier Inc.Peer reviewe

Biosintesis Kopolimer Poli(3-hidroksibutirat-co-4-hidroksibutirat) Menggunakan Substrat Karbon Campuran Asam N-butirat Dan 1,4-butanadiol

BIOSINTESIS KOPOLIMER POLI(3-HIDROKSIBUTIRAT-co-4-HIDROKSIBUTIRAT) MENGGUNAKAN SUBSTRAT KARBON CAMPURAN ASAM n-BUTIRAT DAN 1,4-BUTANADIOL. Kopolimer poli(3-hidroksibutirat-co-4-hidroksibutirat), [P(3HB-co-4HB)] dibiosintesis oleh D. acidovorans menggunakan substrat karbon campuran asam n-butirat dan 1,4-butanadiol. Kondisi optimum biosintesis kopolimer P(3HB-co-4HB) oleh D. acidovorans adalah pada konsentrasi substrat karbon 10 g/L, pH 7,0, waktu inkubasi 72 jam dan suhu inkubasi 26 oC. Kandungan polimer P(3HB-co-4HB) tertinggi diperoleh dengan menggunakan campuran asam n-butirat dan 1,4-butanadiol sebagai substrat karbon. Hasil biosintesis menunjukkan kandungan 4HB meningkat secara linier dari 0 % mol hingga 94 % mol dengan peningkatan kandungan substrat 1,4-butanadiol

Consecutive alcoholic fermentations of white grape musts with yeasts immobilized on grape skins : effect of biocatalyst storage and SO2 concentration on wine characteristics

Abstract Saccharomyces cerevisiae yeasts, immobilized by natural adsorption on grape skins, were used to carry out the alcoholic fermentation step of a winemaking process. The viability of the immobilized cells was evaluated by the implementation of 7 successive fermentations of a white grape must containing 30 mg/L of SO2. The time to complete alcoholic fermentation, the physicochemical characteristics of the produced wines (ethanol, glycerol, organic acids, volatile compounds, color) and sensory properties were evaluated. A traditional fermentation with free cells was used as control. Three other fermentations were conducted after storage of the immobilized biocatalyst (30 d, 4 oC), the first one in the same conditions of the earlier assays, and the other two with higher amounts of SO2 (60 mg/L, 90 mg/L). Wines produced with immobilized cells presented physicochemical and sensory characteristics similar to those traditionally produced with free cells. After three consecutive fermentations, chromatic characteristics became similar to those of traditional wines, but the fermentation time had been reduced from 7 d to 4 d. The fermentative process and the characteristics of the produced wines were not significantly affected by the use of higher amounts of SO2. Immobilized biocatalysts could be stored at least one month without losing its activity.Zlatina Genisheva gratefully acknowledges FCT (Contract/grant number: SFRH/BD/48186/2009) and the Project "BioInd - Biotechnology and Bioengineering for improved Industrial and Agro-Food processes", REF. NORTE-07-0124-FEDER-000028 Co-funded by the Programa Operacional Regional do Norte (ON.2 - O Novo Norte), QREN, FEDER, for the financial support of this work

PENGARUH UKURAN PERUSAHAAN, PROFITABILITAS, PERTUMBUHAN ASSET, DAN RISIKO BISNIS TERHADAP STRUKTUR MODAL PADA PERUSAHAAN MANUFAKTUR YANG TERDAFTAR DI BEI PERIODE 2008 - 2012

The   aim   of   this  research  is  to   kn ow   th e   effect   fi r m   size,  profitability,  growth   of  asset  and   business  risk  to  capital  structure.  The   object   of   this  resea rc h  is  manufacture   compa nies  of   aut omoti ve   and  components  sector  wh ich  listed  in  Ind on e sian  St oc k   Excha ng   fro m   2008  to  20 12 .    Eleven  ma nufacture   company  are   used   as  the   sample  of  this  research   in  autom oti ve   and   components  sector.  The   method   of  the  re s e a r c h   is  purposive   sampling  which   devine   as  a   sa mple   of  ta king   method   which  take  an  object   by   certain    cri teria .   Th e    amount  of  sa m p le    wh ich   requi r e    to    the   criteria   are   11   manufacture   com p a n y   in   Indonesian   St oc k    Exc hang e    by   using   poole d    da ta   method   then  resulti ng   55   observation  da ta.  Data   analysi s  use   linier  regression  analysis  method   which  initia l  by  classic   asum tion   test,   whic h  is  consist  of  normality  test,   autoc o relati on   test,  heterokedastisitas  test  and multikoleniarity  test.  The   hyp othesis  evaluation   done  by  use   of  F   test  and  t  test.    Result   of   data   analysis  or   regression   re s u l t   showed  tha t   simultatily  the   fi rm   size,  p rofi tab ility,   growth   of   asset  and  business  ri sk   are  influencia l  to capital  st ru c t ure .   Pa rc ially,  the   influenc ial variab el  to   capital  struc ture   are   growth  of  asset  and  b usiness  risk   wh ere   as  th e    va ri a b le    of  fi rm    size    and  profitability   are   not   influential  to  capital   st ruc t ure .   The  amount  of  adjusted  R  sq uare   is  0,21 9   it  means  21,9%   depend ent  variable   is  capital  st ruc t u r e   can  be   explained  by  fou r   independe nt    variab le,   th ey   are   firm   size,   p rofitab il ity,   g r owth   of  asset   and  business  risk,  but   78,1%   capita l   structure   explained  by   other  variable   outside   model.

Palinología de Carduus L. y Cirsium Miller (Compositae) en la Península Ibérica

Se han eorudiado a MO 61 mueSiras correspondientes a 4-1 ráxoncs de los géneros Cord11u1 L (29 muesrras de 21ráxon<s) y Cimwn Millcr (32 mucsrras de 23 ráxoncs) de la Penlnsula lbfrica, >rompañandosc oc observaciones a MEU y MET. Los d"ros Cllalitali~s mucscran que ambO$ géneros pr·esentan el mismo tipo polfnico, cscncin!mcntc: granos equin¡,¡do·pcrforados, con delgadas clev;1ciones del tcctum unienc.lo las espinas, cxina con ínfratectum de oolumclas ramificadas, pooo mmlGrOS35, fund:uncntalrncnte bajo bs e.spinas y led:um difer(nciado ce ucs cstrat().\, aunque se puede :.preci:u lln gradiente en la promiDencia de las clet.Jacioll(S del tcc:tum que unen bs espinas y en la densKI:\d d61 so mples bolonging lo 44 raxa or úudtms L (29 ~1m pies or 21 laxa) an<.l Cir· sium Miller (32 samples of 23 taxa) from the lberian Pcni nsula h:wc bccn ~tudicd by LM, SEM and TEM ooservarions. The qualirarivc characrers !how rbar both genera have 1he same polleo pauern, e.ssentially: echiDOpcrforatc grainS¡ with thin ribs bctwee.n the spines. cxiDc v.ith ao i.nfratectum of simple or ramilicd columcl~ rcw in number, gcnerally under the spines acd ccaurn with three 13}U. HoWC.YCr, a gradltnt in thc rib prominence joining the .spiDes and in tbe rnfratedal columeli dcnsity may be apprc:ciatcd. Qunnlit:uivc. data rrom thc measuremcnl of 12 cha.racteu bave been subrnitled toa Prim:ipul Componcnts Analysis. Thc results shuw 11 ccrtain separ.a.tion in the two grou¡)S whi(h corrcspond 10 both gcnc rt~ , :.1· though lherc are somc taxa in an intermediare siruntÍOil. The most significan! characters are rhe PiE ratio (higher in CardJrtu) and rhe apoeoipium si<lc (higher in Cirri11m )