bluuebunny/crossref_metadata_2025 huggingface dataset:
Phasic pulmonary stretch receptor feedback modulates both eupnea and gasping in an in situ rat preparation
Authors: Harris Michael B. , St.-John Walter M.
Published: April 2005

The perfused in situ juvenile rat preparation produces patterns of phrenic discharge comparable to eupnea and gasping in vivo. These ventilatory patterns differ in multiple aspects, including most prominently the rate of rise of inspiratory activity. Although we have recently demonstrated that both eupnea and gasping are similarly modulated by a Hering-Breuer expiratory-promoting reflex to tonic pulmonary stretch, it has generally been assumed that gasping was unresponsive to afferent stimuli from pulmonary stretch receptors. In the present study, we recorded eupneic and gasplike efferent activity of the phrenic nerve in the in situ juvenile rat perfused brain stem preparation, with and without phrenic-triggered phasic pulmonary inflation. We tested the hypothesis that phasic pulmonary inflation produces reflex responses in situ akin to those in vivo and that both eupnea and gasping are similarly modulated by phasic pulmonary stretch. In eupnea, we found that phasic pulmonary inflation decreases inspiratory burst duration and the period of expiration, thus increasing burst frequency of the phrenic neurogram. Phasic pulmonary inflation also decreases the duration of expiration and increases the burst frequency during gasping. Bilateral vagotomy eliminated these changes. We conclude that the neural substrate mediating the Hering-Breuer reflex is retained in the in situ preparation and that the brain stem circuitry generating the respiratory patterns respond to phasic activation of pulmonary stretch receptors in both eupnea and gasping. These findings support the homology of eupneic phrenic discharge patterns in the reduced in situ preparation and eupnea in vivo and disprove the common supposition that gasping is insensitive to vagal afferent feedback from pulmonary stretch receptor mechanisms.
Chronic hypoxia exposure depresses aortic endothelium-dependent vasorelaxation in both sedentary and trained rats: involvement of l-arginine
Authors: Reboul C. , Tanguy S. , Gibault A. , Dauzat M. , Obert P.
Published: April 2005

This study was designed to test the hypothesis that the previously demonstrated training-induced improvement of the endothelium vasodilator function would be blunted under conditions of chronic hypoxia exposure as a result of deleterious effects of hypoxia per se on the nitric oxide pathway. Sea-level-native rats were randomly assigned to N (living in normoxia), NT (living and training 5 days/wk for 5 wk in normoxia), CH (living in hypoxia, 2,800 m), and CHT (living and training 5 days/wk for 5 wk in hypoxia, 2,800 m) groups. Concentration-response curves to acetylcholine (ACh; 10−9 to 10−4 M) with or without l-arginine (10−3 to 10−5 M) and/or nitro-l-arginine methyl ester (10−5 M) were assessed on aortic isolated rings. The main finding was that chronic hypoxia severely depressed maximal ACh-responses of aortic rings in both sedentary and trained groups. However, chronic hypoxia did not interfere with training-induced increases in maximal ACh responses, considering that maximal ACh vasorelaxation was improved in CHT rats to the same extent as in NT rats when both groups were directly compared with their sedentary counterparts. It should be pointed out that the vasodilator response to ACh was restored in CH and CHT rats to the level obtained in N and NT rats, respectively, by an in vitro l-arginine addition. A hypoxia-induced decrease in l-arginine bioavailability resulting from acclimatization at altitude may be involved in this limitation of the NO pathway in CH and CHT rats. These results are of importance for aerobic performance as the specific vascular adaptations to training at altitude could contribute to limit peripheral vasodilatation and subsequently blood flow during exercise.
On the Potential Role of the Corticospinal Tract in the Control and Progressive Adaptation of the Soleus H-Reflex During Backward Walking
Authors: Ung Roth-Visal , Imbeault Marie-Andrée , Ethier Christian , Brizzi Laurent , Capaday Charles
Published: April 2005

When untrained subjects walk backward on a treadmill, an unexpectedly large amplitude soleus H-reflex occurs in the midswing phase of backward walking. We hypothesized that activity in the corticospinal tract (CST) during midswing depolarizes the soleus α-motoneurons subliminally and thus brings them closer to threshold. To test this hypothesis, transcranial magnetic stimulation (TMS) was applied to the leg area of the motor cortex (MCx) during backward walking. Motor-evoked potentials (MEPs) were recorded from the soleus and tibialis anterior (TA) muscles in untrained subjects at different phases of the backward walking cycle. We reasoned that if soleus MEPs could be elicited in midswing, while the soleus is inactive, this would be strong evidence for increased postsynaptic excitability of the α-motoneurons. In the event, we found that in untrained subjects, despite the presence of an unexpectedly large H-reflex in midswing, no soleus MEPs were observed at that time. The soleus MEPs were in phase with the soleus electromyographic (EMG) activity during backward walking. Soleus MEPs increased more rapidly as a function of the EMG activity during voluntary activity than during backward walking. Furthermore, a conditioning stimulus to the motor cortex facilitated the soleus H-reflex at rest and during voluntary plantarflexion but not in the midswing phase of backward walking. With daily training at walking backward, the time at which the H-reflex began to increase was progressively delayed until it coincided with the onset of soleus EMG activity, and its amplitude was considerably reduced compared with its value on the first experimental day. By contrast, no changes were observed in the timing or amplitude of soleus MEPs with training. Taken together, these observations make it unlikely that the motor cortex via the CST is involved in control of the H-reflex during the backward step cycle of untrained subjects nor in its progressive adaptation with training. Our observations raise the possibility that the large amplitude of H-reflex in untrained subjects and its adaptation with training are mainly due to control of presynaptic inhibition of Ia-afferents by other descending tracts.
Phase-Response Curves Give the Responses of Neurons to Transient Inputs
Authors: Gutkin Boris S. , Ermentrout G. Bard , Reyes Alex D.
Published: April 2005

Neuronal firing is determined largely by incoming barrages of excitatory postsynaptic potentials (EPSPs), each of which produce a transient increase in firing probability. To measure the effects of weak transient inputs on firing probability of cortical neurons, we compute phase-response curves (PRCs). PRCs, whose shape can be related to the dynamics of spike generation, document the changes in timing of spikes caused by an EPSP in a repetitively firing neuron as a function of when it arrives in the interspike interval (ISI). The PRC can be exactly related to the poststimulus time histogram (PSTH) so that knowledge of one uniquely determines the other. Typically, PRCs have zero values at the start and end of the ISI, where EPSPs have minimal effects and a peak in the middle. Where the peak occurs depends in part on the firing properties of neurons. The PRC can have regions of positivity and negativity corresponding respectively to speeding up and slowing down the time of the next spike. A simple canonical model for spike generation is introduced that shows how both the background firing rate and the degree of postspike afterhyperpolarization contribute to the shape of the PRC and thus to the PSTH. PRCs in strongly adapting neurons are highly skewed to the right (indicating a higher change in probability when the EPSPs appear late in the ISI) and can have negative regions (indicating a decrease in firing probability) early in the ISI. The PRC becomes more skewed to the right as the firing rate decreases. Thus at low firing rates, the spikes are triggered preferentially by inputs that occur only during a small time interval late in the ISI. This implies that the neuron is more of a coincidence detector at low firing frequencies and more of an integrator at high frequencies. The steady-state theory is shown to also hold for slowly varying inputs.
Dynamic Model of the Octopus Arm. II. Control of Reaching Movements
Authors: Yekutieli Yoram , Sagiv-Zohar Roni , Hochner Binyamin , Flash Tamar
Published: April 2005

The dynamic model of the octopus arm described in the first paper of this 2-part series was used here to investigate the neural strategies used for controlling the reaching movements of the octopus arm. These are stereotypical extension movements used to reach toward an object. In the dynamic model, sending a simple propagating neural activation signal to contract all muscles along the arm produced an arm extension with kinematic properties similar to those of natural movements. Control of only 2 parameters fully specified the extension movement: the amplitude of the activation signal (leading to the generation of muscle force) and the activation traveling time (the time the activation wave takes to travel along the arm). We found that the same kinematics could be achieved by applying activation signals with different activation amplitudes all exceeding some minimal level. This suggests that the octopus arm could use minimal amplitudes of activation to generate the minimal muscle forces required for the production of the desired kinematics. Larger-amplitude signals would generate larger forces that increase the arm’s stability against perturbations without changing the kinematic characteristics. The robustness of this phenomenon was demonstrated by examining activation signals with either a constant or a bell-shaped velocity profile. Our modeling suggests that the octopus arm biomechanics may allow independent control of kinematics and resistance to perturbation during arm extension movements.
No Promises, But I’m Willing to Listen and Tell What I Hear: Conducting Qualitative Research among Prison Inmates and Staff
Authors: Patenaude Allan L.
Published: April 2005

By their nature and locations, prisons are places in which few criminologists study firsthand. It is far easier to gain access to study the residents of a remote Alaskan community than to study the lives of prison inmates and/or those persons whose task it is to keep them within the prison walls. This article explores some of the interrelated challenges (access, rapport, honesty, confidentiality, compromise, etc.) faced by researchers conducting qualitative research within correctional environments. Examples are drawn from the literature as well as recent studies by the author on the work environment of correctional officers and a prison substance abuse treatment program.
Evaluation of Safety and Pharmacokinetics of Consecutive Multiple‐Day Dosing of Palonosetron in Healthy Subjects
Authors: Hunt Thomas L. , Gallagher Susan C. , Cullen Michael T. , Shah Ajit K.
Published: April 2005

This study evaluated the safety and pharmacokinetics of consecutive multiple‐day dosing of palonosetron. Sixteen healthy subjects received an intravenous bolus dose of palonosetron 0.25 mg (n = 12) or placebo (n = 4) daily for 3 consecutive days. Safety was evaluated throughout the study. Serial plasma samples were collected on days 1 and 3 for pharmacokinetic determinations. Three days of dosing with palonosetron 0.25 mg was safe and well tolerated. There were no clinically significant changes from baseline in laboratory values, vital signs, physical examinations, or electrocardiogram intervals. Plasma palonosetron concentrations declined in a biphasic manner, measurable up to 168 hours after dosing on day 3. Mean terminal phase elimination half‐life after day 3 dosing was 42.8 hours. The 2.1‐fold accumulation of palonosetron in plasma following 3 daily doses was predictable based on elimination half‐life of approximately 40 hours, and the maximum plasma concentration remained below the maximum plasma concentration previously observed after a single, well‐tolerated 0.75 mg intravenous bolus dose of palonosetron.
The Red and the Brown: Bolesław Piasecki, the Polish Communists, and the Anti-Zionist Campaign in Poland, 1967-68
Authors: Kunicki Mikołaj
Published: April 2005

This article complements studies on 1968 in Poland that have explained the anti-Semitic campaign by pointing to the Soviet factor, traditional Polish anti-Semitism, or factional conflict within the Polish Communist Party. The article attributes March 1968 to the communists’ growing reliance on Polish nationalism. It narrows the scale of historical observation to the case of Bolesław Piasecki (1915-79), a prominent nationalist politician. A fascist in the 1930s and a proregime Catholic activist after the war, Piasecki was the leading proponent of the mutual reinforcement of nationalism and communism. Melding Piasecki’s role in the 1968 drama with the ideological metamorphosis of the Polish Communist Party, the article argues that under certain conditions, not only did the communists utilize nationalism, but they also prolonged the existence of the nationalist radical right, which supplied the chauvinistic message during the anti-Semitic campaign.
IRF-4 expression in the human myeloid lineage: up-regulation during dendritic cell differentiation and inhibition by 1α,25-dihydroxyvitamin D3
Authors: Gauzzi Maria Cristina , Purificato Cristina , Conti Lucia , Adorini Luciano , Belardelli Filippo , Gessani Sandra
Published: April 2005

Interferon (IFN) regulatory factor (IRF)-4 is a lymphoid- and myeloid-restricted transcription factor of the IRF family. We analyzed its expression during differentiation of human monocytes along the macrophage or the dendritic cell (DC) pathway and in blood myeloid and plasmacytoid DC (M-DC and P-DC, respectively) subsets. Monocyte differentiation into DC, driven by granulocyte macrophage-colony stimulating factor (GM-CSF)/interleukin-4 or GM-CSF/IFN-β, resulted in a strong up-regulation of IRF-4 mRNA and protein, which was further increased by lipopolysaccharide. It is interesting that 1α,25-dihydroxyvitamin D3 [1,25(OH)2D3], a potent inhibitor of DC differentiation, completely abolished IRF-4 up-regulation. IRF-4 was also detected in blood P-DC and M-DC. However, up-regulation upon in vitro culture and down-regulation by 1,25(OH)2D3 was observed in M-DC but not in P-DC. These results point to IRF-4 as a potential player in human myeloid DC differentiation and as a novel target for the immunomodulatory activity of 1,25(OH)2D3.
Cell cycle diversity involves differential regulation of Cyclin E activity in theDrosophilabristle cell lineage
Authors: Audibert Agnès , Simon Françoise , Gho Michel
Published: April 2005

In the Drosophila bristle lineage, five differentiated cells arise from a precursor cell after a rapid sequence of asymmetric cell divisions (one every 2 hours). We show that, in mitotic cells, this rapid cadence of cell divisions is associated with cell cycles essentially devoid of the G1-phase. This feature is due to the expression of Cyclin E that precedes each cell division, and the differential expression of the S-transition negative regulator, Dacapo. Thus, apart from endocycles (G/S), which occurred in two out of five terminal cells, two other cell cycles coexist in this lineage: (1)an atypical cell cycle (S/G2/M), in which the S-phase is initiated during the preceding telophase; and (2) a canonical cell cycle (G1/S/G2/M) with a brief G1 phase. These two types of cell cycle result from either the absence or very transient expression of Dap, respectively. Finally, we show that the fate determinant factor, Tramtrack, downregulates Cyclin E expression and is probably involved in the exit of the cells from the cell cycle.
Transgenic zebrafish reveal stage-specific roles for Bmp signaling in ventral and posterior mesoderm development
Authors: Pyati Ujwal J. , Webb Ashley E. , Kimelman David
Published: April 2005

Bone morphogenetic protein (Bmp) signaling is crucial for the formation and patterning of zebrafish ventral and posterior mesoderm. Mutants defective in the Bmp pathway have expanded trunk muscle, abnormal tails and severely impaired development of ventral mesodermal derivatives such as vasculature,blood and pronephros. As Bmps continue to be expressed in the ventral and posterior mesoderm after gastrulation, it is likely that Bmp signaling continues to play an important developmental role during outgrowth of the posterior body. However, because Bmp signaling plays an essential role during the gastrula stages, it has not been possible with mutants or standard disruption techniques to determine the later functions of the Bmp pathway. To study the role of Bmp signaling in the ventral and posterior mesoderm during trunk and tail outgrowth, we generated a transgenic zebrafish line containing a heatshock-inducible dominant-negative Bmp receptor-GFP fusion. Our data show that Bmps are important for tail organizer formation and for patterning the ventral mesoderm during early gastrulation. However, from mid-gastrulation to the early somitogenesis stages, Bmp signaling is important for ventral tail fin development and for preventing secondary tail formation. We conclude that the role of Bmp signaling in the ventral and posterior mesoderm changes as gastrulation proceeds.
Dual roles of zygotic and maternal Scribble1 in neural migration and convergent extension movements in zebrafish embryos
Authors: Wada Hironori , Iwasaki Miki , Sato Tomomi , Masai Ichiro , Nishiwaki Yuko , Tanaka Hideomi , Sato Atsushi , Nojima Yasuhiro , Okamoto Hitoshi
Published: April 2005

In the developing vertebrate hindbrain, the characteristic trajectory of the facial (nVII) motor nerve is generated by caudal migration of the nVII motor neurons. The nVII motor neurons originate in rhombomere (r) 4, and migrate caudally into r6 to form the facial motor nucleus. In this study,using a transgenic zebrafish line that expresses green fluorescent protein(GFP) in the cranial motor neurons, we isolated two novel mutants, designated landlocked (llk) and off-road (ord), which both show highly specific defects in the caudal migration of the nVII motor neurons. We show that the landlocked locus contains the gene scribble1 (scrb1), and that its zygotic expression is required for migration of the nVII motor neurons mainly in a non cell-autonomous manner. Taking advantage of the viability of the llkmutant embryos, we found that maternal expression of scrb1 is required for convergent extension (CE) movements during gastrulation. Furthermore, we show a genetic interaction between scrb1 and trilobite(tri)/strabismus(stbm) in CE. The dual roles of the scrb1 gene in both neuronal migration and CE provide a novel insight into the underlying mechanisms of cell movement in vertebrate development.
Nuclear receptors Sf1 and Dax1 function cooperatively to mediate somatic cell differentiation during testis development
Authors: Park Susan Y. , Meeks Joshua J. , Raverot Gerald , Pfaff Liza E. , Weiss Jeffrey , Hammer Gary D. , Jameson J. Larry
Published: April 2005

Mutations of orphan nuclear receptors SF1 and DAX1 each cause adrenal insufficiency and gonadal dysgenesis in humans, although the pathological features are distinct. Because Dax1 antagonizes Sf1-mediated transcription in vitro, we hypothesized that Dax1 deficiency would compensate for allelic loss of Sf1. In studies of the developing testis, expression of the fetal Leydig cell markers Cyp17 and Cyp11a1 was reduced in heterozygous Sf1-deficient mice at E13.5, consistent with dose-dependent effects of Sf1. In Sf1/Dax1 (Sf1 heterozygous and Dax1-deleted) double mutant gonads, the expression of these genes was unexpectedly reduced further,indicating that loss of Dax1 did not compensate for reduced Sf1 activity. The Sertoli cell product Dhh was reduced in Sf1 heterozygotes at E11.5, and it was undetectable in Sf1/Dax1 double mutants, indicating that Sf1 and Dax1 function cooperatively to induce Dhh expression. Similarly, Amh expression was reduced in both Sf1 and Dax1 single mutants at E11.5, and it was not rescued by the Sf1/Dax1 double mutant. By contrast, Sox9 was expressed in single and in double mutants, suggesting that various Sertoli cell genes are differentially sensitive to Sf1 and Dax1 function. Reduced expression of Dhh and Amh was transient, and was largely restored by E12.5. Similarly, there was recovery of fetal Leydig cell markers by E14.5, indicating that loss of Sf1/Dax1 delays but does not preclude fetal Leydig cell development. Thus, although Sf1 and Dax1 function as transcriptional antagonists for many target genes in vitro, they act independently or cooperatively in vivo during male gonadal development.
Experimental and numerical investigation of large-bore engines port discharge coefficients
Authors: Keshavarz A , Chapman K , Li Y
Published: April 2005

This paper describes experimental and numerical investigations of the discharge coefficients from the ports in large-bore two-stroke cycle engines. The literature includes some information on the discharge coefficients from very small ports. The literature was found not to include data collected from very large ports, such as in Cooper, Clark, and Worthington two-stroke cycle engines.

The methodology used was to conduct experimental tests and numerical simulations. In the experiments, a flow bench was designed to determine experimentally the discharge coefficients of three primary large-bore engine ports. The obtained data show that there is a considerable difference between the discharge coefficients of the three primary engines used in the natural gas industry. Furthermore, the data substantially differ from the thin-walled discharge coefficient data of the small-port engines reported in the literature.

The numerical model was employed to study the effects of the pressure ratio across the Worthington engine intake ports and port open fraction on the discharge coefficients. As a result, a mathematical model was developed for the discharge coefficients as a function of port geometry, port open fraction, and pressure ratio. Hence the data and model provided in this paper can be used by designers to match turbochargers and aftercoolers better to large-bore engines.
Conjugate Addition of Electron-rich Aromatics to Acrolein in the Confined Space of Zeolite Y
Authors: Imachi Shouhei , Onaka Makoto
Published: April 2005

Acrolein gas was spontaneously entrapped in supercages of NaY zeolite and the sorption was confirmed by solid 13C MAS NMR spectra. In the confined cavities, acrolein smoothly underwent conjugate addition with electron-rich aromatics such as indoles and anisole.
Diet and dementia
Authors: Whalley Lawrence J. , Starr John M. , Deary Ian J.
Published: April 2005

The ageing brain adapts to the accumulation of damage caused by oxidative stress and inflammation. Adaptive processes include neuroprotective and neurorestorative mechanisms. Individual differences in susceptibility to dementia arise when these mechanisms are impaired or are overwhelmed by the molecular pathology of Alzheimer's disease. Neuroprotection relies upon extrinsic and intrinsic defences. An adequate intake of antioxidant micronutrients (eg, vitamin C and vitamin E) and anti-inflammatory macronutrients (eg, omega-3 polyunsaturated fatty acids) forms an essential component of extrinsic defences against brain ageing. There are many epidemiological data to support an association between an inadequate intake of antioxidants and/or fish oils (an important source of omega-3 polyunsaturated fatty acids) and a greater than expected incidence of late onset dementia. These associations are confounded by established links between poverty, poor diet and failing health, especially in old age. Such links may be sufficient to explain some of the effects of an inadequate diet on the retention of cognitive function and increased risk of dementia in old age. More compelling is the association between increased plasma homocysteine concentration and later increased risk of dementia. This association is possibly caused by an inadequate intake of vitamin B12/folate.
Doxorubicin induces EGF receptor-dependent downregulation of gap junctional intercellular communication in rat liver epithelial cells
Authors: Abdelmohsen Kotb , von Montfort Claudia , Stuhlmann Dominik , Gerber P. Arne , Decking Ulrich K.M. , Sies Helmut , Klotz Lars-Oliver
Published: April 2005

Exposure of rat liver epithelial cells to doxorubicin, an anthraquinone derivative widely employed in cancer chemotherapy, led to a dose-dependent decrease in gap junctional intercellular communication (GJC). Gap junctions are clusters of inter-cellular channels consisting of connexins, the major connexin in the cells used being connexin-43 (Cx43). Doxorubicin-induced loss of GJC was mediated by activation of extracellular signal-regulated kinase (ERK)-1 and ERK-2, as demonstrated using inhibitors of ERK activation. Furthermore, activation of the epidermal growth factor (EGF) receptor by doxorubicin was responsible for ERK activation and the subsequent attenuation of GJC. Inhibition of GJC, however, was not by direct phosphorylation of Cx43 by ERK-1/2, whereas menadione, a 1,4-naphthoquinone derivative that was previously demonstrated to activate the same EGF receptor-dependent pathway as doxorubicin, resulting in downregulation of GJC, caused strong phos-phorylation of Cx43 at serines 279 and 282. Thus, ERK-dependent downregulation of GJC upon exposure to quinones may occur both by direct phosphorylation of Cx43 and in a phosphorylation-independent manner.
Butyrylcholinesterase activity and metabolic syndrome in obese patients
Authors: Alcântara Vânia M. , Oliveira Lisangela C. , Réa Rosângela R. , Suplicy Henrique L. , Chautard-Freire-Maia Eleidi A.
Published: April 2005

Total butyrylcholinesterase activity (EC 3.1.1.8) was previously suggested as a marker for metabolic syndrome. The present study examined total butyrylcholinesterase activity and the relative and absolute activities of two butyrylcholinesterase electrophoretic bands (C
Elevated plasma cysteinylglycine levels caused by cilastatin-associated antibiotic treatment
Authors: Badiou Stéphanie , Bellet Hélène , Lehmann Sylvain , Cristol Jean-Paul , Jaber Samir
Published: April 2005

Imipenem (thienamycin formamidine), a broad-spectrum β-lactam antibiotic, is always used in combination with cilastatin in order to avoid the premature breakdown of imipenem by renal tubular dipeptidase. As this dipeptidase also hydrolyzes the glutathione metabolite cysteinylglycine, the therapeutic asso-ciation of imipenem and cilastatin might cause an accumulation of the aminothiol cysteinylglycine. We demonstrate here that when patients are treated with imipenem-cilastatin, their plasma levels of cysteinylglycine are significantly and specifically increased, while cysteine levels are decreased and homocysteine levels are unaffected. We conclude that antibiotic treatment using imipenem-cilastatin induces important metabolic changes that should not remain unrecognized.
Composição florística e abundância de pteridófitas em três ambientes da bacia do rio Guamá, Belém, Pará, Brasil
Authors: Rodrigues Silvane Tavares , Almeida Samuel Soares de , Andrade Laíse de Holanda Cavalcante , Barros Iva Carneiro Leão , Van Den Berg Maria Elizabeth
Published: April 2005

Este artigo apresenta os resultados de análise de composição florística, abundância e aspectos fitossociológicos da flora pteridofítica em três ambientes da Área de Pesquisa Ecológica do Rio Guamá, localizada em Belém, PA. Os ambientes estudados foram floresta terra firme (Reserva Mocambo), Floresta de Igapó (Reserva Catu) e a transição entre estes dois ambientes. Em cada sítio foram sorteadas seis parcelas de 5m x 10 m. Dentro de cada parcela foram registradas as espécies ocorrentes, contados os indivíduos e anotadas as formas de vida. A flora de pteridófitas inventariada foi de 12 espécies distribuídas em 11 gêneros e nove famílias botânicas. A maior riqueza específica medida foi na área de igapó, seguida da área de transição e de terra firme, embora a de terra firme tenha apresentado maior densidade de indivíduos. Algumas espécies apresentam elevada freqüência e abundância em mais de um hábitat, enquanto outras podem ser localmente raras e restritas a um só ambiente. A floresta de igapó apresentou menor similaridade tanto internamente como quando comparada com a de terra firme e a de transição. As epífitas verdadeiras ou holoepífitas dominaram nos três ambientes estudados, sendo mais representativas no igapó, onde a inundação do solo deve inibir as formas terrestres. Estratégias de proteção para este grupo de plantas devem priorizar unidades de conservação que incluam variação ambiental, uma vez que mesmo ambientes próximos e interligados podem incluir considerável número de espécies exclusivas ou restritas.
The ceramic artifacts in archaeological black earth (terra preta) from lower Amazon region, Brazil: mineralogy
Authors: Costa Marcondes Lima da , Kern Dirse Clara , Pinto Alice Helena Eleotério , Souza Jorge Raimundo da Trindade
Published: April 2005

Several archaeological black earth (ABE) sites occur in the Amazon region. They contain fragments of ceramic artifacts, which are very important for the archaeological purpose. In order to improve the archaeological study in the region we carried out a detailed mineralogical and chemical study of the fragments of ceramic artifacts found in the two ABE sites of Cachoeira-Porteira, in the Lower Amazon Region. Their ceramics comprise the following tempers: cauixi, cariapé, sand, sand +feldspars, crushed ceramic and so on and are composed of quartz, clay equivalent material (mainly burned kaolinite), feldspars, hematite, goethite, maghemite, phosphates, anatase, and minerals of Mn and Ba. Cauixi and cariapé, siliceous organic compounds, were found too. The mineralogical composition and the morphology of their grains indicate a saprolite (clayey material rich on quartz) derived from fine-grained felsic igneous rocks or sedimentary rocks as source material for ceramic artifacts, where silica-rich components such cauixi, cariapé and/or sand (feldspar and rock fragments) were intentionally added to them. The high content of (Al,Fe)-phosphates, amorphous to low crystalline, must be product of the contact between the clayey matrix of pottery wall and the hot aqueous solution formed during the daily cooking of animal foods (main source of phosphor). The phosphate crystallization took place during the discharge of the potteries put together with waste of organic material from animal and vegetal origin, and leaving to the formation of the ABE-soil profile.
Estrutura de um trecho de floresta Amazônica na bacia do alto rio Xingu
Authors: Ivanauskas Natália Macedo , Monteiro Reinaldo , Rodrigues Ricardo Ribeiro
Published: April 2005

Este estudo apresenta a estrutura de florestas em Gaúcha do Norte-MT (13° 10'S e 53° 15' O), na borda sul-amazônica. Para o levantamento fitossociológico, três áreas amostrais de 1ha foram subdivididas em 50 parcelas de 10x20m, nas quais foram amostrados todos os indivíduos com perímetro à altura do peito (PAP) >15 cm. Para verificar a similaridade estrutural entre as áreas utilizou-se a Análise de Correspondência. As espécies indicadoras dos ambientes de interflúvio e das áreas sujeitas à inundação foram obtidas através do TWINSPAN e de um sistema de pesos. Concluiu-se que as florestas presentes na bacia do rio Pacuneiro pertencem à mesma unidade fitogeográfica, mas com subtipos florísticos e estruturais de acordo com a posição no relevo, a proximidade dos cursos d'água e o estrato analisado, apresentando predominância de algumas espécies, ou até mesmo possíveis endemismos, em determinados trechos ou estratos. A formação apresentou baixa diversidade alfa (2,91 a 3,50) e beta (3,62 a 3,86), o que não é comum em florestas amazônicas. Várias hipóteses podem explicar essa baixa diversidade, entre elas a baixa precipitação e a alta sazonalidade, o ambiente físico regional aparentemente homogêneo e favorável às espécies competidoras, ou os eventos históricos, relacionados à possível exploração por tribos indígenas ou à recente expansão dessas florestas sobre as áreas savânicas.
Communal egg laying by Gonatodes humeralis (Sauria, Gekkonidae) in Manaus primary and secondary forest areas
Authors: ODA Welton Yudi
Published: April 2005

Communal nesting has been registered for a number of lizard species at different sites. Here it is described communal egg laying of Gonatodes humeralis at different sites near and in human buildings in the period between 1990 and 1998. All these communal nests have been found in the dry season, between April and July, suggesting that the nests of are more common in this season, when the activity of their predators is less intense and the reduction of humidity diminish the decomposition action of the fungi that may kill the eggs.
Composição florística de trechos florestais na borda sul-amazônica
Authors: Ivanauskas Natália Macedo , Monteiro Reinaldo , Rodrigues Ricardo Ribeiro
Published: April 2005

Este estudo apresenta a composição florística de trechos de uma faixa de vegetação de transição existente na região centro-leste do Estado de Mato Grosso, mais precisamente no município de Gaúcha do Norte (13° 10'S e 53° 15' O), onde dá-se o contato entre a Floresta Ombrófila e a Floresta Estacional. O levantamento florístico foi realizado em março de 1999 e bimestralmente a partir de agosto de 1999 até março de 2001, em excursões com duração média de 5 dias, por meio de caminhadas na borda e no interior de florestas, sendo coletadas fanerógamas em fase reprodutiva. Também foram incluídas amostras vegetativas de espécies arbustivo-arbóreas, que não floresceram ou frutificaram durante o período de amostragem, amostradas em 3ha destinados ao levantamento fitossociológico. O levantamento florístico resultou em 72 famílias, 168 gêneros e 268 espécies. Do total de espécies, 66% apresentaram hábito arbóreo e 18% foram lianas. As ervas e arbustos praticamente restringiram-se às áreas de borda ou clareiras, somando 13%. Já a flora epifítica mostrou-se pouco expressiva (1%), quando comparada ao restante da Amazônia, em conseqüência do clima regional mais seco. Hemiepífitas, parasitas e palmeiras constituíram o percentual restante. Constatou-se que 39 espécies amostradas em Gaúcha do Norte ainda não haviam sido depositadas em herbários que mantém coleções representativas da flora matogrossense, enfatizando a carência de coletas nas áreas florestais do Estado.
Tree species diversity in a seasonally-dry forest: the case of the Pinkaití site, in the Kayapó Indigenous Area, Southeastern limits of the Amazon
Authors: Salm Rodolfo
Published: April 2005

This study investigates patterns of forest structure and tree species diversity in an anthropogenic palm grove and undisturbed areas at the seasonally-dry Pinkaití research station, in the Kayapó Indigenous Area. This site, managed by the Conservation International do Brasil, is the most southeastern site floristically surveyed in the Amazon until now. The secondary and a nearby undisturbed forest were sampled in a group of 52 floristic plots of 0.0625-ha (25x25-m) where all trees with DBH > 10 cm were measured and identified. The analyses were complemented with other two floristic plots of 1-ha (10x1000-m). The present study has shown that the Pinkaití, like other seasonally-dry forests, have great heterogeneity in forest structure and composition, associated with biotic characteristics of the most important tree species, natural disturbance and history of land-use. The palm grove, moderately dominated by the arborescent palm Attalea maripa (Aubl.) Mart., presented high tree species diversity and was floristically similar to undisturbed forests at the study site. It is discussed the importance of large arborescent palms for the seasonally-dry Amazon forests regeneration.
Briófitas de Manaus, Amazonas, Brasil
Authors: Yano Olga , Câmara Paulo Eduardo A.S.
Published: April 2005

Foram listadas 74 espécies de briófitas para a cidade de Manaus, Amazonas, sendo 41 espécies de musgos distribuídos em 24 gêneros e 15 famílias e 33 hepáticas em 17 gêneros e sete famílias. Destas, 17 espécies de briófitas são ocorrências novas para Manaus e para o estado do Amazonas. T. ligulaefolium (Bartr.) Buck é uma ocorrência nova para o Brasil. São apresentadas associações com outras briófitas e comparação com outras espécies urbanas.
Análise florística e estrutura de florestas de várzea no estuário amazônico
Authors: Almeida Samuel Soares de , Amaral Dário Dantas do , Silva Antonio Sérgio Lima da
Published: April 2005

Este trabalho apresenta os resultados de análise fitossociológica e da estrutura, feita em 4 inventários florísticos executados em parcelas de 1 hectare de florestas inundáveis de várzea localizadas na área do estuário e do baixo Amazonas. As florestas de várzea do estuário albergam uma riqueza de espécies relativamente baixa em relação a outras áreas da região como as florestas de terra firme. No entanto a estrutura de tamanho é considerável, com as árvores atingindo elevada biomassa vegetal. Provavelmente isto é devido ao aporte constante de nutrientes através dos sedimentos que viajam milhares de quilômetros de distância desde as nascentes andinas até o delta do rio Amazonas. As florestas inundáveis de várzea são dominadas por poucas espécies, algumas com muitos indivíduos, como o açaí (Euterpe oleracea) e o muru-muru (Astrocaryum murumuru), outras com árvores muito grandes como a pitaíca (Swartzia polyphylla), pracuúba (Mora paraensis) e a seringueira (Hevea brasiliensis). A ucuúba (Virola surinamensis), uma espécie que apresenta populações ameaçadas pela exploração madeireira, parece apresentar tanto indivíduos grandes como elevada densidade. As florestas de várzea apresentam baixa similaridade entre si, provavelmente decorrente da imensa variação do ambiente de várzea nos rios, paranás, ilhas e lagos, como os efeitos de zonação, altura de inundação, salinidade, velocidade da água, entre outros fatores. Estratégias de seleção de áreas de várzea para conservação devem levar em conta a variação ambiental, o grau de interferência humana e a diversidade local e entre ambientes.
Biomassa acima do solo de um ecossistema de "campina" em Roraima, norte da Amazônia brasileira
Authors: Barbosa Reinaldo Imbrozio , Ferreira Carlos Alberto Cid
Published: April 2005

Foi estimada a biomassa (viva + morta) acima do solo de um ecossistema de "campina" localizado em Roraima, norte da Amazônia brasileira. A biomassa foi determinada a partir de um inventário fitossociológico (1 ha amostral) e distribuída em dois estratos: (1) gramíneo-lenhoso, composto de "ervas + liquens" (Poaceae, Cyperaceae, Eriocaulaceae, Cladonia spp), Bromeliaceae, plântulas, "litter" fino e grosso e, (2) arbóreo-arbustivo, composto por árvores e arbustos. O estrato gramíneo-lenhoso foi estimado pelo método direto (corte e pesagem) através de 10 quadras de 1m², aproveitando os transectos do inventário. O estrato arbóreo-arbustivo foi estimado pelo método indireto com o corte de 98 indivíduos de diferentes espécies e diâmetros. Foi gerado um modelo para expressar a relação entre a biomassa seca total (kg), a circunferência de base (cm) e a altura total (m) para os indivíduos deste estrato. A equação foi aplicada nos 3.966 indivíduos.ha-1 observados no inventário. A biomassa total foi estimada em 15,91 t.ha-1, sendo 2,20 ± 0,23 t.ha-1 (13,8%) do estrato gramíneo-lenhoso e 13,70 ± 7,13 t.ha-1 (86,2%) do arbóreo-arbustivo. A espécie arbórea de maior biomassa foi Humiria balsamifera (Aubl.) St. Hill. (8,43 t.ha-1), seguida de Pagamea guianensis Aubl. (1,14 t.ha-1). Estes resultados são importantes para refinar os cálculos de emissão de gases do efeito estufa pela queima e decomposição da biomassa acima do solo em ecossistemas de campinas na Amazônia.
One-winged Drosophila subobscura: a phenotype with an obscure genetic basis
Authors: Orengo Dorcas J. , Hauschteck-Jungen Elisabeth , Mestres Francesc
Published: April 2005

A line of one-winged Drosophila subobscura was studied. The absent wing is substituted by a bulky structure with macro and microchaetes, showing a thoracic appearance. Genetic crosses showed that there is no way to select for the trait by simple crossing. The number of one-winged flies in the various generations was always low. In one case a wingless fly was also obtained. The trait presents an unknown genetic pattern.
Genetic variability of Prochilodus lineatus (Characiformes, Prochilodontidae) in the upper Paraná river
Authors: Revaldaves Eloísa , Renesto Erasmo , Machado Maria F.P.S.
Published: April 2005

The genetic variability of the "curimba", Prochilodus lineatus, from three locations in the Paraná river basin, was investigated by starch gel electrophoresis. A total of 160 specimens were analyzed for 19 enzymes, 12 of which permitted successful interpretation of electrophoretic patterns. Eighteen loci were identified and six of them proved to be polymorphic (EST-1*, EST-2*, IDH-1*, PGM-1*, PGM-2*, LDH-2*). Mean heterozygosity was considered high (13%) by comparison with the literature. A low level of differentiation was found among subpopulations, with mean F ST = 0.018. Values of genetic distance and genetic identity suggest that, at least along this stretch of the river, P. lineatus comprises a single breed with high gene flow. This analysis has important implications for fishery management, aquaculture, and conservation of the stocks
Milheto (Pennisetum glaucum (L.) R.Br.) como substituto do milho em rações para codornas-japonesas em postura (Coturnix coturnix japonica)
Authors: Leandro N.S.M. , Stringhini J.H. , Café M.B. , França A.F.S. , Freitas S.A.
Published: April 2005

Avaliou-se o desempenho de codornas-japonesas em postura alimentadas com níveis crescentes de milheto-grão na ração. Duzentas codornas com 70 dias de idade, submetidas a um delineamento inteiramente ao acaso, com cinco tratamentos e quatro repetições de 10 aves, receberam níveis de milheto de 0, 25, 50, 75 e 100% em substituição ao milho em rações na fase de postura. Foram medidos a produção e o peso dos ovos, o consumo de ração, a mortalidade, a coloração da gema pelo leque colorimétrico, e calculada a conversão alimentar em termos de massa e de dúzia de ovos. Os índices de produtividade das codornas não foram afetados pelos diferentes níveis de substituição estudados e o milheto-grão se constituiu em uma fonte de substituição do milho para codornas-japonesas, devendo-se, porém, incluir na ração uma fonte de pigmentação para a gema dos ovos.
Eficiência técnica e econômica de quatro empresas de produção de leite da região de São Carlos, SP
Authors: Mancio A.B. , Schiffler E.A. , Londoño Hernández F.I.
Published: April 2005

Avaliaram-se os índices zootécnicos, os custos de produção e a rentabilidade de quatro empresas de produção de leite tipo B, no Estado de São Paulo, no período de maio de 1995 a abril de 1996. Foram feitas análise descritiva e comparação entre as empresas. Alta produtividade significou maior benefício econômico. A produção de leite em escala tem influência decisiva no custo total do litro de leite. Análises de viabilidade produtiva de sistemas de produção necessariamente devem compor análises de custos e receitas.
Componentes de (co)variância e parâmetros genéticos de características de crescimento da raça Simental no Brasil
Authors: Marques L.F.A. , Pereira J.C.C. , Oliveira H.N. , Pereira C.S. , Bergmann J.A.G.
Published: April 2005

Informações de genealogia e produção, cedidas pela Associação Brasileira de Criadores da Raça Simental (ABCRS), relativas aos pesos desde o nascimento até um ano de idade, foram utilizadas para estimar, sob modelos alternativos, os componentes de variância e os parâmetros genéticos em animais da raça Simental no Brasil. A matriz de parentesco incluiu 25.812 animais dos quais 7587 com dados de produção. O modelo 1 contém, além do erro, o efeito genético direto. Os modelos seguintes contêm os componentes do modelo 1, mais o efeito permanente de ambiente materno (modelo 2), ou o componente genético materno (modelo 3), ambos os componentes (modelo 5), os componentes do modelo 3 mais a covariância entre os efeitos genéticos direto e materno (modelo 4) e todos os componentes citados (modelo 6). Os modelos foram comparados pelo teste de razão de verossimilhança pelo chi² (P<0,01). Os componentes de variância e os valores de herdabilidades, estimados para os efeitos direto e materno, foram decrescentes, desde o modelo 1 até o modelo 6, na razão direta em que o modelo incorpora mais efeitos aleatórios. Para a fase de aleitamento foi encontrada variância genética nula, entretanto, alto valor para a variância de ambiente permanente. Os efeitos maternos, genético e de ambiente permanente são importantes para a raça Simental no Brasil e devem ser considerados em programas de seleção. Entretanto, os valores mais elevados de herdabilidade materna, encontrados com modelos sem efeito de ambiente permanente, sugerem que o método utilizado não discrimina apropriadamente esses efeitos, oriundos de mesma fonte de variação.
Avaliação nutricional do fósforo disponível de quatro fontes de fósforo para suínos em fase de terminação
Authors: Veloso J.A.F. , Medeiros S.L.S.
Published: April 2005

O experimento teve como objetivo avaliar a inclusão de fontes de fósforo (P), considerando-se seu fósforo disponível, sobre o desempenho de suínos em fase de terminação (60 a 100kg). As fontes avaliadas foram: fosfato bicálcico padrão (FBP), fosfato supertriplo (FST), fosfato monoamônio (FMA) e a consorciação de fosfato bicálcico padrão (80%) com o fosfato de Patos de Minas (FPM - 20%). Foram utilizados 32 leitões, machos, castrados, mestiços de raça tipo carne, com peso médio de 60kg. O delineamento experimental utilizado foi o inteiramente ao acaso, com 4 tratamentos, com 4 repetições de 2 animais cada. As dietas foram isoprotéicas e isoenergéticas adequadas para a fase de terminação. Avaliaram-se o ganho de peso, o consumo de ração, a conversão alimentar e o consumo de flúor. Foram observadas diferenças significativas (P<0,05) entre tratamentos somente para ganho de peso e consumo de ração. O fosfato supertriplo foi significativamente inferior aos demais fosfatos, apresentando o menor ganho de peso (37,4kg). Porém, não houve diferença no ganho de peso entre os animais alimentados com os fosfatos FBP (40,45kg), FMA (40,45kg) e a mistura de 20% de FPM e 80% de FBP (45,10kg). Também não houve diferença no consumo de ração em função dos fosfatos FBP (133,91kg), FMA (144,70kg) e da mistura de 20% FPM e 80% de FBP (146,71kg). A conversão alimentar não foi afetada pelos fosfatos, variando entre 3,24 e 3,54. O consumo de flúor, diferiu estatisticamente nos quatro tratamentos, sendo maior nos animais alimentados com 20% de FPM (30,80g), seguido do FST (9,24g), FBP (3,65g) e FMA (2,16g). Os níveis de fósforo disponível das fontes avaliadas revelaram-se adequados para suínos em fase de terminação, portanto a adoção dos valores de biodisponibilidade do fósforo dos suplementos deve ser um critério recomendado nas formulações e rações. As fontes de fósforo testadas podem ser recomendadas para utilização em rações de suínos em fase de terminação, ressaltando a indicação da consorciação do fosfato de Patos de Minas com outro fosfato de qualidade superior.