Search for first-generation scalar leptoquarks in p(p)over-bar collisions at root s=1.96 TeV

We report on a search for pair production of first-generation scalar leptoquarks (LQ) in p (p) over bar collisions at root s=1.96 TeV using an integrated luminosity of 252 pb(-1) collected at the Fermilab Tevatron collider by the D0 detector. We observe no evidence for LQ production in the topologies arising from LQ(LQ) over bar -> eqeq and LQ(LQ) over bar -> eq nu q, and derive 95% C.L. lower limits on the LQ mass as a function of beta, where beta is the branching fraction for LQ -> eq. The limits are 241 and 218 GeV/c(2) for beta=1 and 0.5, respectively. These results are combined with those obtained by D0 at root s=1.8 TeV, which increases these LQ mass limits to 256 and 234 GeV/c(2).

Search for pair production of first-generation leptoquarks in p(p)over-bar collisions at root s=1.96 TeV

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Search for first generation leptoquark pair production in the electron plus missing energy plus jets final state

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Natural radioactivity and radon exhalation rate in Brazilian igneous rocks

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Taxas de cruzamento em uma população natural de Cryptocarya Moschata Nees (Lauraceae)

O sistema de cruzamento da espécie arbórea de dossel da Mata Atlântica brasileira, Cryptocarya moschata, foi estudado a partir de material proveniente do Parque Estadual Carlos Botelho, São Miguel Arcanjo, São Paulo, Brasil. As taxas de cruzamento foram determinadas através de marcadores alozímicos obtidos de plântulas germinadas de coortes de sementes coletadas de 35 árvores. O valor médio da taxa de cruzamento de equilíbrio (estimador indireto) foi t^eq = 0.51. As estimativas das taxas de cruzamento uniloco e multilocos (estimadores diretos) foram t^s = 0.725± 0,041 e t^m = 0,884 ± 0,034, respectivamente, indicando um sistema de cruzamento predominantemente alogâmico. As taxas de cruzamento de árvores individuais variaram de 27 a 100 ( x¯ = 87,8) porcento, a partir de t^m calculado com as freqüências gênicas de pólen mantidas constantes ao nível populacional. A partir do modelo de par de irmãos (modelo de cruzamento correlacionado) de Ritland, a correlação entre duas progênies irmãs oriundas de autofecundação (r^s) e a correlação entre duas progênies irmãs oriundas de paternidade por exocruzamento (r^p) foram 35,7% e 99,0%, respectivamente. Esses resultados corroboram o fato de haver variação nas taxas de autocruzamento entre as diferentes árvores, podendo também indicar que quando há endogamia, a maior parte das sementes nas árvores são provavelmente irmãs-germanas.

Adrenoceptors of the medial septal area modulate water intake and renal excretory function induced by central administration of angiotensin II

We investigated the role of alpha-adrenergic antagonists and clonidine injected into the medial septal area (MSA) on water intake and the decrease in Na+, K+ and urine elicited by ANGII injection into the third ventricle (3rdV). Male Holtzman rats with stainless steel cannulas implanted into the 3rdV and MSA were used. ANGII (12 nmol/µl) increased water intake (12.5 ± 1.7 ml/120 min). Clonidine (20 nmol/µl) injected into the MSA reduced the ANGII-induced water intake (2.9 ± 0.5 ml/120 min). Pretreatment with 80 nmol/µl yohimbine or prazosin into the MSA also reduced the ANGII-induced water intake (3.0 ± 0.4 and 3.1 ± 0.2 ml/120 min, respectively). Yohimbine + prazosin + clonidine injected into the MSA abolished the ANGII-induced water intake (0.2 ± 0.1 and 0.2 ± 0.1 ml/120 min, respectively). ANGII reduced Na+ (23 ± 7 µEq/120 min), K+ (27 ± 3 µEq/120 min) and urine volume (4.3 ± 0.9 ml/120 min). Clonidine increased the parameters above. Clonidine injected into the MSA abolished the inhibitory effect of ANGII on urinary sodium. Yohimbine injected into the MSA also abolished the inhibitory effects of ANGII. Yohimbine + clonidine attenuated the inhibitory effects of ANGII. Prazosin injected into the MSA did not cause changes in ANGII responses. Prazosin + clonidine attenuated the inhibitory effects of ANGII. The results showed that MSA injections of alpha1- and alpha2-antagonists decreased ANGII-induced water intake, and abolished the Na+, K+ and urine decrease induced by ANGII into the 3rdV. These findings suggest the involvement of septal alpha1- and alpha2-adrenergic receptors in water intake and electrolyte and urine excretion induced by central ANGII.

Interaction between paraventricular nucleus and septal area in the control of physiological responses induced by angiotensin II

We determined the effects of losartan (40 nmol) and PD 123319 (40 nmol) (both non-peptides and selective antagonists of the AT1 and AT2 angiotensin receptors, respectively), and [Sar¹, Ala8] angiotensin II (ANG II) (40 nmol) (a non-selective peptide antagonist of angiotensin receptors) injected into the paraventricular nucleus (PVN) on the water and salt appetite, diuresis and natriuresis and mean arterial pressure (MAP) induced by administration of 10 nmol of ANG II into the medial septal area (MSA) of male Holtzman rats weighing 250-300 g. The volume of drug solution injected was 0.5 µl over a period of 10-15 s. The responses were measured over a period of 120 min. ANG II alone injected into the MSA induced an increase in all the above parameters (8.1 ± 1.2, 1.8 ± 0.3, and 17.1 ± 1.0 ml, 217 ± 25 µEq/120 min, and 24 ± 4 mmHg, respectively, N = 10-12) compared with vehicle-treated rats (1.4 ± 0.2, 0.6 ± 0.1, and 9.3 ± 0.5 ml, 47 ± 5 µEq/120 min, and 4.1 ± 0.8 mmHg, respectively, N = 10-14). Pretreatment with losartan and [Sar¹, Ala8] ANG II completely abolished the water and sodium intake, and the pressor increase (0.5 ± 0.2, 1.1 ± 0.2, 0.5 ± 0.2, and 0.8 ± 0.2 ml, and 1.2 ± 3.9, 31 ± 4.6 mmHg, respectively, N = 9-12), whereas losartan blunted the urinary and sodium excretion induced by ANG II (13.9 ± 1.0 ml and 187 ± 10 µEq/120 min, respectively, N = 9). Pretreatment with PD 123319 and [Sar¹, Ala8] ANG II blocked the urinary and sodium excretion (10.7 ± 0.8, 9.8 ± 0.7 ml, and 67 ± 13 and 57 ± 17 µEq/120 min, respectively, N = 9), whereas pretreatment with PD 123319 partially blocked the water and sodium intake, and the MAP induced by ANG II administration (2.3 ± 0.3, 1.1 ± 0.1 ml, and 12 ± 3 mmHg, respectively, N = 9-10). These results suggest the angiotensinergic effect of the MSA on the AT1 and AT2 receptors of the PVN in terms of water and sodium homeostasis and MAP modulation.

AV3V LESION SUPPRESSES THE PRESSOR, DIPSOGENIC AND NATRIURETIC RESPONSES TO CHOLINERGIC ACTIVATION OF THE SEPTAL AREA IN RATS

In the present study we investigated the effect of anteroventral third ventricle (AV3V) lesion on pressor, dipsogenic, natriuretic and kaliuretic responses induced by the injection of carbachol (a cholinergic agonist) into the medial septal area (MSA) of rats. Male rats with sham or AV3V lesion and a stainless-steel cannula implanted into the MSA were used. Carbachol (2 nmol) injected into the MSA in sham lesion rats produced pressor (43 +/- 2 mmHg), dipsogenic (9.6 +/- 1.2 ml/h), natriuretic (531 +/- 82-mu-Eq/120 min) and kaliuretic (164 +/- 14-mu-Eq/120 min) responses. In AV3V-lesioned rats (1-5 days and 14-18 days), the pressor (11 +/- 2 mmHg, respectively), dipsogenic (1.9 +/- 0.7 and 1.4 +/- 0.6 ml/h), natriuretic (21 +/- 5 and 159 +/- 44-mu-Eq/120 min) and kaliuretic (124 +/- 14 and 86 +/- 13-mu-Eq/120 min) responses induced by carbachol injection into the MSA were reduced. These results show that the AV3V region is essential for the pressor, dipsogenic, natriuretic and kaliuretic responses induced by cholinergic activation of the MSA in rats.

Central interaction between atrial natriuretic peptide and angiotensin II in the control of sodium intake and excretion in female rats

We investigated the effects of estrogen on sodium intake and excretion induced by angiotensin II (ANG II), atrial natriuretic peptide (ANP) or ANG II plus ANP injected into the median preoptic nucleus (MnPO). Female Holtzman rats weighing 250-300 g were used. Sodium ingestion and excretion 120 min after the injection of 0.5 mu l of 0.15 M NaCl into the MnPO were 0.3 +/- 0.1 ml (N = 12) and 29 +/- 7 mu Eq in intact rats, 0.5 +/- 0.2 ml (N = 10) and 27 +/- 6 mu Eq in ovariectomized rats, and 0.2 +/- 0.08 (N = 11) and 38 +/- 8 mu Eq in estrogen-treated ovariectomized (50 mu g/day for 21 days) rats, respectively. ANG II (21 mu M) injection in intact, ovariectomized, and estrogen-treated ovariectomized rats increased sodium intake (3.8 +/- 0.4, 1.8 +/- 0.3 and 1.2 +/- 0.2 ml/120 min, respectively) (N = 11) and increased sodium excretion (166 +/- 18, 82 +/- 22 and 86 +/- 12 mu Eq/120 min, respectively) (N = 11). ANP (65 mu M) injection in intact (N = 11), ovariectomized(N = 10)and estrogen-treated ovariectomized (N = 10) rats increased sodium intake (1.4 +/- 0.2, 1.8 +/- 0.3, and 1.7 +/- 0.3 ml/120 min, respectively) and sodium excretion (178 +/- 19, 187 +/- 9, and 232 +/- 29 mu Eq/120 min, respectively). Concomitant injection of ANG II and ANP into the MnPO of intact (N = 12), ovariectomized (N = 10) and estrogentreated ovariectomized (N = 10) rats caused smaller effects than those produced by each peptide given alone: 1.3 +/- 0.2, 0.9 +/- 0.2 and 0.3 +/- 0.1 ml/120 min for sodium intake, respectively, and 86 +/- 9, 58 +/- 7, and 22 +/- 4 mu Eq/120 min for sodium excretion, respectively. Taken together, these results demonstrate that there is an antagonistic interaction of ANP and ANG II on sodium intake and excretion, and that reproductive hormones affect this interaction.

Losartan (DUP-753) blocks the natriuretic, kaliuretic and antidiuretic effect of intracerebroventricular injection of carbachol in water-loaded rats

We determined the effect of intracerebroventricular (icv) administration of losartan, an angiotensin II (ANG II) subtype 1 receptor (AT1) antagonist, on icv carbachol-induced natriuresis, kaliuresis and antidiuresis in water-loaded male Holtzman rats (250-300 g) with a cannula implanted into the lateral ventricle (LV). The rats were water loaded with 5% of their body weight by gavage twice, with the second gavage one hour after the first. Carbachol (2 nmol in 1 mu l) was injected icv immediately after the second load. When losartan (DUP-753, 50 nmol in 1 mu l) was administered icv, it was given 3 min before carbachol. Previous icv treatment with losartan significantly reduced the icv carbachol-induced natriuresis (324 +/- 17 mu Eq/120 min), kaliuresis (103 +/- 15 mu Eq/120 min) and antidiuresis (13.5 +/- 2.1 ml/120 min) compared to the effects of previous icv injection of saline (Nai excretion = 498 +/- 22 mu Eq/120 min; K+ excretion = 167 +/- 20 mu Eq/120 min; urine volume = 5.2 +/- 1.2 ml/120 min). These results, reported as means +/- SEM for 12 rats in each group, are consistent with the hypothesis that AT1 subtype receptors participate in the regulation of body electrolyte balance.

AV3V LESION REDUCES THE PRESSOR, DIPSOGENIC, AND NATRIURETIC RESPONSES TO VENTROMEDIAL HYPOTHALAMUS ACTIVATION

In the present study, we investigated the effect of anteroventral third ventricle (AV3V) lesion on pressor, tachycardic, dipsogenic, natriuretic, and kaliuretic responses induced by the injection of the cholinergic agonist carbachol into the ventromedial hypothalamic nucleus (VMH) of rats. Male rats with sham or AV3V lesion and a stainless steel cannula implanted into the VMH were used. Carbachol (2 nmol) injected into the VMH of sham rats produced pressor (32 +/- 4 mmHg). tachycardic (83 +/- 14 bpm), dipsogenic (8.2 +/- 1.1 ml/h). natriuretic (320 +/- 46-mu-Eq/120 min), and kaliuretic (155 +/- 20-mu-Eq/120 min) responses. In AV3V-lesioned rats (2 and 15 days), the pressor (4 +/- 2 and 15 +/- 2 mmHg. respectively), dipsogenic (0.3 +/-0.2 and 1.4 +/- 0.7 ml/h), natriuretic (17 +/- 7 and 99 +/- 21-mu-Eq/120 min), and kaliuretic (76 +/- 14 and 79 +/- 7-mu-Eq/120 min) responses induced by carbachol injection into the VMH were reduced. The tachycardia was also abolished (27 +/- 15 and -23 +/-29 bpm, respectively). These results show that the AV3V region is essential for the pressor, tachycardic, dipsogenic, natriuretic. and kaliuretic responses induced hy cholinergic activation of the VMH in rats.

Sn-polymetallic greisen-type deposits associated with late-stage rapakivi granites, Brazil: fluid inclusion and stable isotope characteristics

Tin-polymetallic greisen-type deposits in the Itu Rapakivi Province and Rondonia Tin Province, Brazil are associated with late-stage rapakivi fluorine-rich peraluminous alkali-feldspar granites. These granites contain topaz and/or muscovite or zinnwaldite and have geochemical characteristics comparable to the low-P sub-type topaz-bearing granites. Stockworks and veins are common in Oriente Novo (Rondonia Tin Province) and Correas (Itu Rapakivi Province) deposits, but in the Santa Barbara deposit (Rondonia Tin Province) a preserved cupola with associated bed-like greisen is predominant. The contrasting mineralization styles reflect different depths of formation, spatial relationship to tin granites, and different wall rock/fluid proportions. The deposits contain a similar rare-metal suite that includes Sri (+/-W, +/-Ta, +/-Nb), and base-metal suite (Zn-Cu-Pb) is present only in Correas deposit. The early fluid inclusions of the Correas and Oriente Novo deposits are (1) low to moderate-salinity (0-19 wt.% NaCl eq.) CO2-bearing aqueous fluids homogenizing at 245-450 degreesC, and (2) aqueous solutions with low CO2, low to moderate salinity (0-14 wt.% NaCl eq.), which homogenize between 100 and 340 T. In the Santa Barbara deposit, the early inclusions are represented by (1) low-salinity (5-12 wt.% NaCl eq.) aqueous fluids with variable CO2 contents, homogenizing at 340 to 390 T, and (2) low-salinity (0-3 wt.% NaCl eq.) aqueous fluid inclusions, which homogenize at 320380 degreesC. Cassiterite, wolframite, columbite-tantalite, scheelite, and sulfide assemblages accompany these fluids. The late fluid in the Oriente Novo and Correas deposit was a low-salinity (0-6 wt.% NaCl eq.) CO2-free aqueous solution, which homogenizes at (100-260 degreesC) and characterizes the sulfide fluorite-sericite association in the Correas deposit. The late fluid in the Santa Barbara deposit has lower salinity (0-3 wt.% NaCl eq.) and characterizes the late-barren-quartz, muscovite and kaolinite veins. Oxygen isotope thermometry coupled with fluid inclusion data suggest hydrothermal activity at 240-450 degreesC, and 1,0-2.6 kbar fluid pressure at Correas and Oriente Novo. The hydrogen isotope composition of breccia-greisen, stockwork, and vein fluids (delta(18)O quartz from 9.9parts per thousand to 10.9parts per thousand, deltaDH(2)O from 4.13parts per thousand to 6.95parts per thousand) is consistent with a fluid that was in equilibrium with granite at temperatures from 450 to 240 degreesC. In the Santa Barbara deposit, the inferred temperatures for quartz-pods and bed-like greisens are much higher (570 and 500 degreesC, respectively), and that for the cassiterite-quartz-veins is 415 degreesC. The oxygen and hydrogen isotope composition of greisen and quartz-pods fluids (delta(18)O(qtz-H2O)=5.5-6.1parts per thousand) indicate that the fluid equilibrated with the albite granite, consistent with a magmatic origin. The values for mica (delta(18)O(mica-H2O)=33-9.8parts per thousand) suggest mixing with meteoric water. Late muscovite veins (delta(18)O(qtz-H2O)=-6.4parts per thousand) and late quartz (delta(18)O(mica-H2O)=-3.8parts per thousand) indicate involvement of a meteoric fluid. Overall, the stable isotope and fluid inclusion data imply three fluid types: (1) an early orthomagmatic fluid, which equilibrated with granite; (2) a mixed orthomagmatic-meteoric fluid; and (3) a late hydrothermal meteoric fluid. The first two were responsible for cassiterite, wolframite, and minor coluChange in the redox conditions related to mixing-of magmatic and meteoric fluids favored important sulfide mineralization in the Correas deposit. (C) 2004 Elsevier B.V. All rights reserved.

Pressor, dipsogenic, natriuretic and kaliuretic responses to central carbachol in rats with lesion of the medial septal area

In the present study we investigated the effect of electrolytic lesion of the medial septal area (MSA) on the dipsogenic, natriuretic, kaliuretic and pressor responses elicited by intracerebroventricular (i.c.v.) injection of the cholinergic agonist carbachol. Freely moving rats with sham or MSA lesion (1-7 days and 14-18 days) and a stainless steel cannula implanted into the lateral ventricle were studied. In sham rats, i.c.v. injection of carbachol (7.5 nmol) produced an increase in water intake (10.2 ± 1.5 ml/h), mean arterial pressure (MAP) (35 ± 5 mmHg) and urinary Na+ and K+ excretion (551 ± 83 and 170 ± 17 μEq 120 min, resp.). The pressor (18 ± 3 and 14 ± 4 mmHg, resp.) and natriuretic responses (178 ± 58 and 172 ± 38 μEq 120 min) produced by i.c.v. carbachol in acute or chronic MSA-lesioned rats were reduced. No change was observed in urinary K+ excretion and a reduced water intake (5 ± 1.3 ml/h) was observed only in acute MSA-lesioned rats. These results suggest that the MSA plays an important role for the pressor and natriuretic responses induced by central cholinergic activation in rats. A small influence of this structure on water intake may also be suggested. © 1991.

Effect of AV3V lesion on the cardiovascular, fluid, and electrolytic changes induced by activation of the lateral preoptic area

In this study we investigated the effect of the anteroventral third ventricle (AV3V) lesion on the pressor, bradycardic, natriuretic, kaliuretic, and dipsogenic responses induced by the injection of the cholinergic agonist carbachol into the lateral preoptic area (LPOA) in rats. Male Holtzman rats with sham or electrolytic AV3V lesion were implanted with stainless steel cannula directly into the LPOA. Injection of carbachol (7.5 nmol) into the LPOA of sham rats induced natriuresis (405 ± 66 μEq/120 min), kaliuresis (234 ± 44 μEq/120 min), water intake (9.5 ± 1.7 ml/60 min), bradycardia (-47 ± 11 bpm), and increase in mean arterial pressure (28 ± 3 mmHg). Acute AV3V lesion (1-5 days) reduced the natriuresis (12 ± 4 μEq/120 min), kaliuresis (128 ± 27 μEq/120 min), water intake (1.7 ± 0.9 ml/60 min), and pressor responses (14 ± 4 mmHg) produced by carbachol into the LPOA. Tachycardia instead of bradycardia was also observed. Chronic (14-18 days) AV3V lesion reduced only the pressor response (10 ± 2 mmHg) induced by carbachol. These results showed that acute, but not chronic, AV3V lesion reduced the natriuretic, kaliuretic, and dipsogenic responses to carbachol injection into the LPOA. The pressor response was reduced in acute or chronic AV3V-lesioned rats. The results suggest that the lateral areas may control the fluid and electrolyte balance independently from the AV3V region in chronic AV3V-lesioned rats. © 1992.

Signal and backgrounds for the single production of scalar and vector leptoquarks at the CERN LHC

We perform a detailed analysis of the potentiality of the CERN Large Hadron Collider to study the single production of leptoquarks via pp→e±q→ leptoquark →e± q, with e± generated by the splitting of photons radiated by the protons. Working with the most general SU(2)L⊗U( 1 )Y invariant effective Lagrangian for scalar and vector leptoquarks, we analyze in detail the leptoquark signals and backgrounds that lead to a final state containing an e± and a hard jet with approximately balanced transverse momenta. Our results indicate that the LHC will be able to discover leptoquarks with masses up to 2-3 TeV, depending on their type, for Yukawa couplings of the order of the electromagnetic one.