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Aluminum is one of the most important heavy metals inducing stress during plant growth and development. In this study, transgenic rice (Oryza sativa L., cv. Kitaake) plants expressing the maize C4PEPC and PPDK genes were evaluated for aluminum tolerance. A 4.3 and 19.1 folds increase of PPDK and PEPC activities in transgenic rice produced increases in root exudation of oxalate, malate, and citrate (1.20, 1.41, and 1.65 times, respectively) compared to untransformed (WT) plants. Transgenic rice had enhanced aluminum tolerance compared to WT based on chlorophyll fluorescence and chlorophyll levels. Transgenic plants under aluminum stress also had decreased lipid membrane oxidative damage and higher levels of ROS-scavenging enzyme activity. The PEPC and PPDK genes play an important role in aluminum stress tolerance by increasing the effluxes of organic acids.

Within the next-to-leading order (NLO) perturbative QCD (pQCD) parton model, suppression of away-side hadron spectra associated with a high $p_{T}$ photon due to parton energy loss is shown to provide a complete tomographic picture of the dense matter formed in high-energy heavy-ion collisions at RHIC. Dictated by the shape of the $\gamma$-triggered jet spectrum in NLO pQCD, hadron spectra at large $z_T=p_T^{h}/p_T^{\gamma} \stackrel{>}{\sim} 1$ are more susceptible to parton energy loss and therefore are dominated by surface emission of $\gamma$-triggered jets, whereas small $z_{T}$ hadrons mainly come from fragmentation of jets with reduced energy from volume emission. These lead to different centrality dependence of the hadron suppression in different regions of $z_{T}$., Comment: 4 pages, 3 figures, proceedings for QM 2009 conference

Using data from the TPC/Two-Gamma experiment at the SLAC [ital e][sup +][ital e[minus]] storage ring PEP, a [ital C]=+1 resonance has been observed in the [pi][sup +][pi][sup [minus]][pi][sup 0][gamma] final state resulting from the fusion of one nearly real and one quite virtual photon. The actual decay channel is probably [pi][sup +][pi][sup [minus]][pi][sup 0][pi][sup 0], where one final-state photon is not detected, and the mass of the fully reconstructed state would be approximately 1525 MeV. A four-pion decay mode in turn implies that the resonance has even isospin. The nonobservation of this [ital R](1525) when both initial-state photons are nearly real suggests a spin-1 assignment. Since the large measured value of the product of the branching ratio into [pi][sup +][pi][sup [minus]][pi][sup 0][pi][sup 0] and the [gamma][gamma] coupling makes it unlikely that this state is the mostly [ital [bar s]s] [ital f][sub 1](1510), its interpretation may lie outside of conventional meson spectroscopy. There is a second, less-significant enhancement observed in the same reaction at a four-pion mass centered around 2020 MeV.

Two-photon production of the charmonium state χ c has been studied by the TPC/Two-Gamma experiment at the SLAC e + e − collider PEP. We observe evidence of the χ c 2 state in the channel γγ → χ c 2 , χ c 2 → γJ / ψ , J / ψ → l + l − and obtain a value of Γ γγ ( χ c 2 )=3.4±1.7±0.9 keV. This is the first observation of the two-photon production of a χ c state. Comparison is made with previous experimental results and QCD predictions for Γ γγ ( χ c 2 ).

We have measured the polarization of {ital D}{sup *}, the energy dependence of the polarization, and the spin-density matrix of {ital D}{sup *} in {ital e}{sup +}{ital e{minus}} annihilation at a center-of-mass energy of 29 GeV using the Time Projection Chamber detector at the SLAC storage ring PEP. In 147 pb{sup {minus}1} of data we see no strong evidence for polarization, alignment, or final-state interactions in this fragmentation process.

We present a measurement of the total cross section for {gamma}{gamma}{r arrow}hadrons, with one photon quasireal and the other a spacelike photon of mass squared {minus}{ital Q}{sup 2}. Results are presented as a function of {ital Q}{sup 2} and the {gamma}{gamma} center-of-mass energy {ital W}, with the {ital Q}{sup 2} range extending from 0.2 to 60 GeV{sup 2}, and {ital W} in the range from 2 to 10 GeV. The data were taken with the TPC/Two-Gamma facility at the SLAC {ital e}{sup +}{ital e}{sup {minus}} storage ring PEP, which was operated at a beam energy of 14.5 GeV. The cross section exhibits a gentle falloff with increasing {ital W}. Its {ital Q}{sup 2} dependence is shown to be well described by an incoherent sum of vector-meson and pointlike scattering over most of the observed {ital W} range. Agreement at high {ital Q}{sup 2} is improved if a minimum-{ital p}{sub {ital T}} cutoff (motivated by QCD) is imposed on the pointlike contribution.

Medium modification of dihadron fragmentation functions due to gluon bremsstrahlung induced by multiple partonic scattering is studied in both deep-inelastic scattering (DIS) off large nuclei and high-energy heavy-ion collisions within the same framework of twist expansion. The modified fragmentation functions for dihadrons are found to follow closely that of single hadrons leading to a weak nuclear suppression of their ratios as measured by HERMES in DIS experiments. Meanwhile, a moderate medium enhancement of the near-side correlation of two high transverse momentum hadrons with increasing centrality is found in heavy-ion collisions because of the trigger bias and the increase in parton energy loss with centrality. Successful comparisons between theory and experiment for multi-hadron observables in both confining and deconfined environments offers comprehensive evidence for partonic energy loss as the mechanism of jet modification in dense matter., 4 pages, Revtex, 2 figures, revised figures and discussion

Endoscopic ligation has been extensively applied in the management of esophageal and gastric varices with or without bleeding. The varices are automatically eradicated through the use of ligation. However, whether avascular necrosis will occur in a gastrointestinal polyp when the base is ligated remains unclear. The aims of this pilot study were to investigate the sequential changes of gastric hyperplastic polyps following endoscopic detachable snare ligation and to determine the possibility of induction of avascular necrosis in these lesions following ligation.Eleven patients with eighteen gastric hyperplastic polyps were treated with endoscopic detachable-snare ligation. The polyps were observed for 5 minutes and biopsies were then conducted. At 14 days after endoscopic ligation, follow-up endoscopies were performed to assess the outcome of the strangulated polyps.After being strangulated by the detachable snares, a majority of the polyps immediately congested (94%), and then developed cyanotic change (89%) approximately 4 minutes later. Pathological examination revealed severe venous congestion in the lamina propria of the strangulated polyps. On follow-up endoscopy 2 weeks later, all the snares had dropped off, and avascular necrosis occurred in sixteen polyps (89%). All of the polyps with avascular necrosis were detected to have developed cyanotic changes in initial endoscopy. No complications occurred during or following the ligation procedure.Most gastric hyperplastic polyps develop avascular necrosis following ligation by detachable snare. Cyanotic change is an important predictor of the outcomes of the lesions following endoscopic ligation. The application of this ligation technique in treatment of bleeding or non-bleeding gastrointestinal polyps deserves further investigation.

Medium modification of parton fragmentation functions induced by multiple scattering and gluon bremsstrahlung is shown to describe the recent HERMES data in deeply inelastic scattering (DIS) very well, providing the first evidence of $A^{2/3}$-dependence of the modification. The energy loss is found to be $ \approx 0.5$ GeV/fm for a 10-GeV quark in a $Au$ nucleus. Including the effect of expansion, analysis of the $\pi^0$ spectra in central $Au+Au$ collisions at $\sqrt{s}=130$ GeV yields an averaged energy loss equivalent to $ \approx 7.3$ GeV/fm in a static medium. Predictions for central $Au+Au$ collisions at $\sqrt{s}=200$ GeV are also given., Comment: 4 pages in RevTex with 3 ps figures, final version published in Phys. Rev. Letters

The first order correction to the parton fragmentation functions in a thermal medium is derived in the leading logarithmic approximation in the framework of thermal field theory. The medium-modified evolution equations of the parton fragmentation functions are also derived. It is shown that all infrared divergences, both linear and logarithmic, in the real processes are canceled among themselves and by corresponding virtual corrections. The evolution of the quark number and the energy loss (or gain) induced by the thermal medium are investigated., Comment: 21 pages in RevTex, 10 figures

The authors sought to evaluate the effect of gamma knife radiosurgery (GKS) on growth hormone (GH)-producing pituitary adenoma growth and endocrinological response.From 1993 to 1997, 79 patients with GH-producing pituitary adenomas were treated with GKS. Seventy-six patients had acromegaly. Sixty-eight patients were treated with GKS as the primary procedure. The tumor margin was covered with a 50 to 90% isodose and the margin dose was 18 to 35 Gy (mean 31.3 Gy). The dose to the visual pathways was less than 10 Gy except in one case. Sixty-eight patients (86%) were followed for 6 to 52 months. Growth hormone levels declined with improvement in acromegaly in all cases in the first 6 months after GKS. Normalization of the hormone levels was achieved in 23 (40%) of 58 patients who had been followed for 12 months and in 96% of cases for more than 24 months (43 of 45), or more than 36 months (25 of 26), respectively. With the reduction of GH hormone levels, 12 of 21 patients with hyperglycemia regained a normal blood glucose level (p0.001). The tumor shrank in 30 (52%) of 58 patients who had been followed for 12 months (p0.01), 39 (87%) of 45 patients for more than 2 years (p = 0.02), and 24 (92%) of 26 patients for more than 36 months. In the remainder of patients tumor growth ceased.Gamma knife radiosurgery for GH-producing adenomas showed promising results both in hormonal control and tumor shrinkage. A margin dose of more than 30 Gy would seem to be effective in improving the clinical status, reducing high blood glucose levels, and normalizing hypertension.

The authors report on two patients who underwent radiosurgery for torsion spasm and evaluate the efficiency of gamma knife radiosurgery (GKS) as an alternative treatment. The first patient was a 33-year-old woman with severe right-sided lower-limb torsion dystonia. The second patient was a 20-year-old man with right-sided upper-limb torsion dystonia. The target was located at the anterior portion of the ventrolateral nucleus. The maximum doses were 150 Gy and 145 Gy, respectively. Double isocenters with a 4-mm collimator were used. Follow up lasted for 18 months and 8 months, respectively. Both patients had excellent clinical improvement 2 to 3 months after GKS, respectively. The authors believe that GKS may be a safe and efficient treatment for torsion spasm.

The authors analyzed the outcome of 53 patients with cavernous hemangiomas who underwent gamma knife radiosurgery (GKS) and evaluated the benefit of the treatment.From 1994 to 1995, 57 patients were treated with GKS for cavernous hemangiomas. The mean margin dose to the lesions was 20.3 Gy (range 14.5-25.2 Gy) and the prescription isodose was 50 to 80%. The mean follow-up period was 4.2 years. Four patients were lost to follow up. In 18 of 28 patients whose chief complaint was seizures, there was a decrease in seizure frequency. Five of 23 patients with hemorrhage suffered rebleeding 4 to 39 months after GKS. Seventeen patients in whom the hemangiomas were located at the frontal or parietal lobe had neurological disability and in five this was severe. Two patients underwent resection of their hemangioma after GKS. Three experienced visual problems. Follow-up imaging demonstrated shrinkage of the lesion in 19 patients.A higher margin dose (16 Gy) may be associated with a reduction in the incidence of rebleeding after GKS. Higher dosage and severe brain edema after GKS may decrease the frequency and intensity of seizures at least temporarily. Gamma knife radiosurgery may play a role in protection against hemorrhage and in reduction of the rate of seizure in selected cases with the appropriate dose.

The purpose of this study was to estimate the efficacy of gamma knife radiosurgery (GKS) in controlling tumor growth and endocrinopathy associated with prolactinomas.Between 1993 and 1997, 164 of 469 patients with pituitary adenomas treated by GKS harbored prolactinomas. The dose to the tumor margin ranged from 9 to 35 Gy (mean 31.2 Gy), and the visual pathways were exposed to a dose of less than 10 Gy. The mean tumor diameter was 13.4 mm. The mean follow-up time for 128 cases was 33.2 months (range 6-72 months). Tumor control was observed in all but two patients who underwent surgery 18 and 36 months, respectively, after GKS. Clinical cure was achieved in 67 cases. Clinical improvement was noted with a decrease in the hyperprolactinemia after GKS. Nonetheless, in 31 (29%) of 108 patients who were followed for more than 2 years no improvement in serum prolactin levels was demonstrated, although this could be normalized by bromocriptine administration after treatment. Nine infertile women became pregnant 2 to 13 months after GKS and all gave birth to normal children. There was no visual deterioration related to GKS. Five women experienced premature menopause. In these patients there was subtotal disappearance of the tumor and an empty sella developed.Gamma knife radiosurgery as a primary treatment for prolactinomas can be safe and effective both for controlling tumor growth and for normalization of prolactin hypersecretion. A higher margin dose (or = 30 Gy) seemed to be associated with a better clinical outcome. Gamma knife radiosurgery may make prolactinomas more sensitive to the bromocriptine.

Endoscopic sphincterotomy and basket extraction are currently used to remove bile duct stones, with a duct clearance rate of 85% to 90%. A biliary endoprosthesis (stent) is an alternative method to treat difficult cases, especially high-risk surgical patients. The aim of this study was to investigate the long-term effect of biliary endoprostheses in patients with irretrievable common bile duct stones.From December, 1990, to November, 1998, 546 patients were referred to the Veterans General Hospital-Kaohsiung for endoscopic removal of common bile duct stones. Of them, 12 received long-term biliary endoprosthesis because endoscopic removal or surgery was not suitable. Large-caliber stents (10 French) were inserted into 12 patients (5 women and 7 men, mean age, 78.4 years) and they were followed up with regular clinical visits. Quantitative cholescintigraphy was performed in four patients to evaluate biliary emptying after liver function returned to normal.No early complications from stent insertion occurred and a satisfactory resolution of jaundice, pain and fever were noted in all patients. One patient had repeated cholangitis due to stent occlusion and five died from unrelated causes. The median effective period of stent placement was 11 months (range, 1-38 months). Quantitative cholescintigraphy revealed delayed biliary drainage in four patients despite an absence of symptoms after their liver function returned to normal.Large-caliber stents are a safe and effective treatment for long-term palliation in high-risk patients with retained common bile duct stones.

To determine the change of oesophageal manometry in patients with oesophageal varices before and after oesophageal variceal ligation (EVL).Forty-five patients who had liver cirrhosis and oesophageal varices with high risk of bleeding were managed by EVL. Oesophageal manometry was performed just prior to the ligation and 4-6 weeks after obliteration of varices. Another 45 age- and sex-matched patients without hepatic, oesophageal or systemic disease served as the control group.At 5 cm above the lower oesophageal sphincter (LES), the amplitude of the contractive wave was significantly lower in patients before EVL (56.9 +/- 31.8 vs 80.1 +/- 30.1, P1.05) and returned to the level of control subjects after EVL (76.5 +/- 37.0 vs 80.1 +/- 30.1, P0.05). At 10 cm above LES, the amplitude of the contractive wave was significantly lower in patients before and after EVL than the control group (54.3 +/- 29.2 vs 68.1 +/- 29.5, 54.2 +/- 26.0 vs 68.1 +/- 29.5, respectively, P0.05). The percentage of tertiary waves was significantly higher in patients before and after EVL than in the control group (31.4 +/- 36.6 vs 5.8 +/- 15.1, 26.9 +/- 32.9 vs 5.8 +/- 15.1, respectively, P0.05). However, no significant swallowing disturbance was noted in patients after EVL. There was significantly greater LES length in patients before EVL (4.0 +/- 0.9 vs 3.4 +/- 0.7, P0.05) but there was no significant difference in the LES length after EVL as compared with the control group. Eighty-six per cent (39/45) of patients developed paraoesophageal varices and 31% (14/45) developed new varices 6 months after variceal obliteration. However, there was no significant difference in manometry at the time of variceal obliteration between patients with variceal recurrence and those without.The presence of varices affected oesophageal motility. However, such abnormality had little clinical significance. Endoscopic variceal ligation normalized oesophageal motility and may not induce abnormal oesophageal motility. The manometric change can not be used to predict the recurrence of varices in cirrhotic patients after variceal obliteration.

Dysfunction of the sphincter of Oddi (SOD) is one of the causes of postcholecystectomy syndrome and biliary pain. Endoscopic sphincterotomy (EST) is recommended in some patients refractory to conservative treatment. This study was designed to evaluate the efficacy of, and complications from EST in patients with SOD.Between 1990 and 1993, 24 patients clinically diagnosed as having papillary stenosis were treated by endoscopic sphincterotomy. All patients had dilated common bile duct (CBD) in addition to 1) elevation of transaminases and alkaline phosphatase (n = 13); 2) elevation of transaminases and serum amylase (n = 4); 3) normal liver enzymes but delayed biliary emptying on quantitative hepatobiliary scintigraphy (QHS) (n = 7). No CBD stones, organic obstruction or other disorders were found in these patients.EST was successfully performed in 24 patients. One patient had minor hemorrhage and one patient developed pancreatitis after EST. Twenty-two of the 24 patients (91.7%) were symptomatically improved before discharge. Twenty-one patients were regularly followed over a median period of 18 months (range 5-36) after EST. Two patients with symptom had recurrence at five and eight month follow up because of restenosis of papilla; another two patients with recurrent biliary symptoms, but the sphincter of Oddi remained wide open. Seventeen of 21 regularly followed patients were symptom free after the median 18-month follow up.EST is an effective and safe modality for treatment of sphincter of Oddi dysfunction.

Endoscopic nasobiliary drainage (ENBD) is a safe and effective modality which has been well documented for obstructive jaundice. However, factors predicting success rate of ENBD remain inconclusively. This study analyses those factors and discusses the outcome of patients with obstructive jaundice.One hundred and sixteen patients (male 99, female 17; mean age 68.2 years) with obstructive jaundice received ENBD after endoscopic retrograde cholangiogram (ERC) by Olympus JF-lT20 endoscope and 7F Wilson-Cook nasobiliary catheter from Sep. 1990 to Oct. 1993. Bile output (QD), serum bilirubin (BIW), liver biochemistry (QW), bile culture (next day), blood culture (if BT38.5 degrees C) were checked until definite treatment or death. Adequate drainage was defined as a daily output of bile more than 200cc, a gradual drop in serum bilirubin and no signs of cholangitis. Factors such as causes of jaundice, obstruction level, serum bilirubin, albumin, juxtapapillary diverticulum (JPD), bacteremia, fever before ERCP and ascites were analyzed.The success rate was 86.2% (100/116) in ERC and 78% (78/100) in ENBD. Adequate biliary drainage was 82.1% (64/78), and serum bilirubin was reduced from 14.3 +/- 8.5 mg% to 7.5 +/- 5.6 mg% within one week. In patients with non-cancerous causes, higher success rate and adequate drainage rate were obtained compared with those with cancerous causes (94.3% vs. 69.2%, p0.01 and 88.6% vs. 50.8%, p0.01, respectively). In all patients, a higher success rate was achieved at the obstruction level at the common bile duct (CBD) compared with periampullary and hilar levels (90.7% vs 69.2%, p0.05 and 90.7% vs 28.6%, p0.001, respectively). In patients with cancer as a cause, higher success rate was achieved at CBD level than at hilar level (85% vs 28.6%, p0.05). Those patients with cancer and serum bilirubin above 15 mg/dl had a higher failure rate in ENBD. Success rate of ENBD was not related to the presence of JPD, bacteremia or fever before ERCP and serum albumin level.Factors decreasing the success rates of ENBD were underlying cancerous causes, obstruction level at hilum or periampullary region and serum bilirubin level more than 15 mg%.

We present branching fraction measurements of three-prong decays of the [tau][sup [minus]] lepton based on data from the TPC/Two-Gamma detector at SLAC PEP. The decays are classified according to the identities of the charged tracks to give simultaneous measurements of [ital B][[tau][sup [minus]][r arrow][nu][sub [tau]] [ital K][sup [minus]][pi][sup +][pi][sup [minus]]]=0.58[sub [minus]0.13][sup +0.15]% and [ital B][[tau][sup [minus]][r arrow][nu][sub [tau]] [ital K][sup [minus]][ital K][sup +][pi][sup [minus]]]=0.15[sub [minus]0.07][sup +0.09]%, and upper limits of [ital B][[tau][sup [minus]][r arrow][nu][sub [tau]][pi][sup [minus]][ital K][sup +][pi][sup [minus]]][lt]0.25%, [ital B][[tau][sup [minus]][r arrow][nu][sub [tau]] [ital K][sup [minus]][pi][sup +][ital K][sup [minus]]][lt]0.09%, and [ital B][[tau][sup [minus]][r arrow][nu][sub [tau]] [ital K][sup [minus]][ital K][sup +][ital K][sup [minus]]][lt]0.21%, where additional neutrals may be present in each case. The branching fractions are normalized to the world average three-prong topological branching fraction and there is an estimated 20% systematic error in addition to the listed statistical errors. We find the mass distributions in the [ital K][sup [minus]][pi][sup +][pi][sup [minus]] decay are consistent with [ital K][sub 1] dominance, and obtain branching fractions of [ital B][[tau][sup [minus]][r arrow][nu][sub [tau]] [ital K][sub 1][sup [minus]](1270)]=0.41[sub [minus]0.35][sup +0.41]% and [ital B][[tau][sup [minus]][r arrow][nu][sub [tau]] [ital K][sub 1][sup [minus]](1400)]=0.76[sub [minus]0.33][sup +0.40]%.

Nuclear shadowing effects are checked in the production of direct photons and neutral pions in heavy-ion collisions at RHIC/LHC energy within a next-to-leading order perturbative QCD parton model. The transverse momentum dependence of the nuclear modification factors is presented in p + A and A + A collisions to distinguish different parameterizations for nuclear shadowing effects. Our numerical results show that in central A + A collisions the nuclear modification factor for direct photons is more sensitive to shadowing effects than the factor for pion hadrons, and it is a powerful observable to discriminate different parameterizations for parton distributions.

The TPC/Two-Gamma Collaboration has measured the inclusive cross section for production of charmed D∗± mesons in photon-photon collisions. The reaction utilized was e+e-→e+e-D∗±X, with D∗±→DOπ+-, DO→K-+π ±, and either zero or one outgoing e± detected. The result, σ(e + e - → e + e - D ∗± X) = 74±26±19 pb , is in agreement with the quark parton mo del prediction for e+e- → e+e-c c , combined with a Lund model for the hadronization of the charmed quarks.

We report a measurement of the reaction ..gamma gamma -->..K/sup +/K/sup -/..pi../sup +/..pi../sup -/ in both tagged and untagged events at PEP. The cross section rises with invariant ..gamma gamma.. mass to about 15 nb at 2 GeV and falls slowly at higher masses. We find clear evidence for the processes ..gamma gamma -->..phi..pi../sup +/..pi../sup -/ and ..gamma gamma -->..K/sup asterisk0/(892)K..pi... Upper limits (95% C.L.) of 1.5 and 5.7 nb in the mass range from 1.7 to 3.7 GeV are obtained for phirho/sup 0/ and K/sup asterisk0/K/sup asterisk0/ production, respectively.

The inclusive production cross sections and transverse momentum distributions of ${K}^{*0}$ and ${{K}_{S}}^{0}$ mesons in ${e}^{+}{e}^{\ensuremath{-}}$ annihilation at a center-of-mass energy of 29 GeV have been measured by means of the time projection chamber detector in the PEP-4 experiment. The mean multiplicites are found to be 0.49 \ifmmode\pm\else\textpm\fi{} 0.04(stat.) \ifmmode\pm\else\textpm\fi{} 0.07(syst.) (${K}^{*0}+{\stackrel{-}{K}}^{*0}$) and 1.22 \ifmmode\pm\else\textpm\fi{} 0.03(stat.) \ifmmode\pm\else\textpm\fi{}0.15(syst.) (${K}^{0}+{\stackrel{-}{K}}^{0}$) per event.

We report a measurement of the ${e}^{+}{e}^{\ensuremath{-}}\ensuremath{\rightarrow}{e}^{+}{e}^{\ensuremath{-}}p\overline{p}{\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}$ process with the TPC/Two-Gamma facility at the PEP ${e}^{+}{e}^{\ensuremath{-}}$ storage ring at SLAC. Forty-five $p\overline{p}{\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}$ events were identified in data corresponding to an integrated ${e}^{+}{e}^{\ensuremath{-}}$ luminosity of 142 ${\mathrm{pb}}^{\ensuremath{-}1}$. The cross section for $\ensuremath{\gamma}\ensuremath{\gamma}\ensuremath{\rightarrow}p\overline{p}{\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}$ is given both as a function of the $\ensuremath{\gamma}\ensuremath{\gamma}$ center-of-mass energy ${W}_{\ensuremath{\gamma}\ensuremath{\gamma}}$, with ${W}_{\ensuremath{\gamma}\ensuremath{\gamma}}$ between 2.5 and 5.5 GeV, and as a function of the in variant mass squared ${q}^{2}$ of one of the photons, with $\ensuremath{-}{q}^{2}l7$ Ge${\mathrm{V}}^{2}$. This cross section falls much less rapidly with ${W}_{\ensuremath{\gamma}\ensuremath{\gamma}}$ than does the cross section for a similar process, $\ensuremath{\gamma}\ensuremath{\gamma}\ensuremath{\rightarrow}p\overline{p}$. No ${\ensuremath{\Delta}}^{0}{\overline{\ensuremath{\Delta}}}^{0}$ production is observed, and only a small fraction of the events at low ${W}_{\ensuremath{\gamma}\ensuremath{\gamma}}$ is consistent with $\ensuremath{\gamma}\ensuremath{\gamma}\ensuremath{\rightarrow}{\ensuremath{\Delta}}^{++}{\overline{\ensuremath{\Delta}}}^{\ensuremath{-}\ensuremath{-}}$, ${\ensuremath{\Delta}}^{++}\overline{p}{\ensuremath{\pi}}^{\ensuremath{-}}$, or ${\overline{\ensuremath{\Delta}}}^{\ensuremath{-}\ensuremath{-}}p{\ensuremath{\pi}}^{+}$. In an expanded search through the same data, four events compatible with either $\ensuremath{\Lambda}\overline{\ensuremath{\Lambda}}(\ensuremath{\Lambda}\ensuremath{\rightarrow}p{\ensuremath{\pi}}^{\ensuremath{-}})$ or ${\ensuremath{\Sigma}}^{0}\overline{\ensuremath{\Lambda}}({\ensuremath{\Sigma}}^{0}\ensuremath{\rightarrow}\ensuremath{\Lambda}\ensuremath{\gamma})$ production were found.

The inclusive production cross section of ..lambda.., anti ..lambda.. in e/sup +/e/sup -/ annihilation at a c.m. energy of 29 GeV has been measured with the time-projection-chamber detector at PEP. The average lambda, anti lambda multiplicity has been measured to be 0.197 +/- 0.012 (stat.) +/- 0.017 (syst.). ..lambda..-anti..lambda.. pairs have been observed in jets for the first time, and the average number of ..lambda..-anti..lambda.. pairs per event has been measured to be 0.042 +/- 0.017 +/- 0.014. 8 references, 3 figures.

The distribution of particles in three-jet events is compared with the predictions of three fragmentation models currently in use: the Lund string model, the Webber cluster model, and an independent fragmentation model. The Lund model and, to a certain extent, the Webber model provide reasonable descriptions of the data. The independent fragmentation model does not describe the distribution of particles at large angles with respect to the jet axes. The results provide evidence that the sources of hadrons are Lorentz boosted with respect to the overall c.m.

Three currently used fragmentation models are tested by studying the distribution of particles between jet axes in the 3-jet events ofe+e− annihilation, using data collected by the Time Projection Chamber at PEP. These three models — the Lund String model, the Webber Cluster model and an Independent Fragmentation model (IF) — each implement different Lorentz-frame structures for the fragmentation process of quarks and gluons into hadrons. The Lund model provides a good description of the data, while the IF model does not. The Webber model, which is untuned, does not describe the absolute particle densities between jets, but correctly predicts the ratios of those densities, which are less sensitive to the tuning.

We use the time-projection chamber detector to study mechanisms of baryon production in the central rapidity region of jets from e/sup +/e/sup -/ annihilation. On the basis of angular correlations between protons and antiprotons, we exclude the isotropic decay of heavy mesonic clusters as a dominant source of baryons at 95% confidence level. The diquark mechanisms used in string fragmentation models reproduce the data, provided that diquarks are formed in a two-step process which allows mesons to be produced in between the baryon and antibaryon.

Using the data accumulated at LEP in 1989 and 1990 with the ALEPH detector, the inclusive and exclusive branching ratios of the τ lepton have been measured assuming lepton universality inZ0 decays. The inclusive branching fractions for the τ decay into one, three, and five charged particles have been determined to be (85.45±0.97)%, (14.35±0.48)%, and (0.10±0.05)%, respectively, in agreement with the world averages. New undetected decay modes are determined to have a branching fraction of less than 2.1% at 95% CL. The measured branching ratios for quasi-exclusive channels are slightly larger than, but consistent with the world averages, except for the modes τ→3 hadrons+v τ andτ→hadron+2π0v τ , which are significantly larger. These latter branching ratios have been found to be (9.5±0.7)% and (10.2±1.1)%, respectively. The sum of all the measured quasi-exclusive branching ratios is (100.4±1.8)%. A fully exclusive analysis of modes with neutral pions shows no evidence for new photonic decay modes with a branching fraction limit of 3.4% at 95% CL.

Inclusive production cross sections for photons and π0's ine + e − annihilation at a center of mass energy of 29 GeV have been measured. The π0 production spectrum agrees with a corresponding measurement for π±. The ratio of the π0 inclusive rate to the average for π± is 0.92±0.14. The fractions of the total energy carried by photons and π0's are 0.244±0.016 and 0.217±0.033, respectively. The fraction of total energy carried by all stable hadrons, prompt leptons and photons is determined to be 0.938±0.045, leaving 0.062±0.045 for neutrinos.

Two-photon production of ${K}_{S}^{0}{K}^{\ifmmode\pm\else\textpm\fi{}}{\ensuremath{\pi}}^{\ensuremath{\mp}}$ states has been studied by the TPC/Two-Gamma experiment at the SLAC storage ring PEP. A resonance of mass 1.42 GeV was seen when one of the photons was quite virtual but not when both photons were nearly real. Production of a spin-1 meson, which cannot be made by two real photons, would fit these observations. The ${Q}^{2}$ dependence of the data in the resonance region agrees with this spin assignment and is incompatible with a spin-0 hypothesis. The mass and width of the resonance are similar to those of the $E$ meson, which has been assigned ${J}^{P}={0}^{\ensuremath{-}}$ and ${J}^{P}={1}^{+}$ by different experiments.

By observing the reaction ..gamma gamma -->..K-italic/sub s-italic//sup 0/K/sup +-/..pi../sup minus-or-plus/, the TPC/Two-Gamma experiment at the SLAC e-italic/sup +/e/sup -/ storage ring PEP has obtained a 95%-confidence-level limit of GAMMA/sub iota//sub ..-->..//sub ..gamma..//sub ..gamma../B(iota..-->..KK-bar..pi..) ..//sub ..gamma..//sub ..gamma../ limit appears to conflict with previous assignments of an observed rho..gamma.. decay to iota and also with many analyses of eta-eta'-iota mixing. The contrast of this small ..gamma gamma.. width with the large rate for J-italic/psi..--> gamma..iota is evidence that the iota is a glueball with little admixture of q-italicq-bar states.

We study long-range correlations between hadrons in opposite jets ine+e− annihilation events at\(\sqrt s \)=29 GeV. We use the data to measure differences between quark and antiquark fragmentation functions into charged hadrons, and to estimate the variation of fragmentation properties among quark flavors. We find large variations in longitudinal fragmentation functions, but universal mean transverse momenta of hadrons in jets.

We compare the particle flow in the event plane of three-jet qq-barg (quark-antiquark-gluon) events with the particle flow in radiative annihilation events qq-bar..gamma.. (quark-antiquark-photon) for similar kinematic configurations. In the angular region between quark and antiquark jet, we find a significant decrease in particle density for qq-barg as compared to qq-bar..gamma... This effect is predicted in QCD as a result of destructive interference between soft-gluon radiation from quark, antiquark, and hard gluon.

Evidence for a narrow state decaying into an F meson and a photon has been obtained in e/sup +/e/sup -/ annihilation events at 29 GeV c.m. energy. This state lies 139.5 +- 8.3(stat) +- 9.7(syst) MeV above the F-meson mass and is consistent with the expected F( meson. The F mesons are identified by a peak in the K/sup +/K/sup -/..pi../sup + -/ mass at 1.948 +- 0.028 +- 0.010 GeV.

We measure an inclusive branching fraction of (13.9 +- 2.0/sub -2.2//sup +1.9/)% for the decay tau/sup -/..--> nu../sub tau/..pi../sup -/..pi../sup 0/+nh/sup 0/ (ngreater than or equal to1), where h/sup 0/ is a ..pi../sup 0/ or an eta. The data sample, obtained with the time-projection chamber detector facility at the SLAC e/sup +/e/sup -/ storage ring PEP, corresponds to an integrated luminosity of 72 pb/sup -1/ at 29-GeV center-of-mass energy. The measured branching fraction is somewhat greater than the theoretical prediction and, with errors taken into account, could resolve the present difference between the inclusive and the sum of the exclusive tau/sup +- / branching fractions into one charged prong.

Four hybridomas stably secreting monoclonal antibodies (McAbs) against human growth hormone (hGH) have been obtained by fusion of immunized mice spleen cells with myeloma SP2/0 cells. After inoculation of hybridoma cells to BALB/c mice i.p., the ascitic fluids were collected and characterized, the titre of the 4 McAbs being in the range of 0.6-10.0 X 10(5). As determined by Ouchterlony analysis, all the 4 McAbs were IgG1. They varied in affinities, with equilibrium constants from 0.53 X 10(9) to 9.0 X 10(9) L/mol. McAb-1 showed 52.5% cross-reactivity with human placental lactogen (hPL). McAb-2, McAb-3 and McAb-4 displayed no crossreactivity with hPL and human prolactin (hPRL). Antigenic determinants recognized by the 4 McAbs were mapped through their reactions with hGH fragment consisting of residues 1-43, cross-reaction with hPL, hPRL and antibody-antibody competition test. The results showed that the antigenic determinants of the McAbs are not located in the site of hGH comprising residues 1-43 but on the three non-overlapping antigenic sites of hGH. As shown in receptor assay, all the 4 McAbs exhibited specific inhibition on the binding of pregnant rabbit liver GH receptor to 125I-hGH. It seems likely that receptor-binding site is larger than the antigenic determinant or there are more than one site on hGH surface capable of binding to the hormone receptor. The McAbs could only bind with the peak 2 (MW22000) but not the peak 1 (MW 45000) of old 125I-hGH after gel filtration.(ABSTRACT TRUNCATED AT 250 WORDS)

According to the data of a retrospective epidemiological survey, the annual standardized lung cancer death rate in Xuan Wei County, Yuen-Nan Province was 25.95 per 100,000 during 1973–75. Sex ratio of the death rates is 0.98 to 1. The highest rate, up to 151.78 per 100,000, was recorded in one commune. As it has been customary to burn locally produced smoke coal in shallow pits indoors without chimneys, concentrations of coal smoke are usually high. The preliminary studies on the carcinogenicity of soot extract from Xuan Wei are presented.