Effect of zone and crops rotation on Ischaemum rugosum and resistance to bispyribac-sodium in Ariari, Colombia

The objectives of this research were to evaluate (1) weed species presented in rice fields in relation to the geographical zone and crop rotation and (2) the resistance level of Ischaemum rugosum to the herbicide bispyribac-sodium. For the first objective, were sampled 79 commercial fields of rice to establish weed density, coverage, and rotation system in the evaluated fields with record of bispyribac-sodium application of at least five years. To reach the second objective, the seeds were collected from plants in commercial fields with different control levels of bispyribac-sodium herbicide. Seeds were germinated in trays under controlled conditions. When plants presented three leaves these were treated with bispyribac-sodium at different doses. Percentages of control and dry weight of plants were evaluated 12 days after treatments (dat). Dominant species in evaluated fields was I. rugosum, with a frequency of 100%, presenting escapes to different chemical commercial treatments. No significant differences were recorded between rotation systems, nevertheless, the most of I. rugosum population was found in the system rice-fallow-rice. The response of applications at different concentrations allows concluding that 65% of samples had resistance at different degrees reported as indexes from 2 to 42 which are related to rotation systems.

How and why to measure the germination process?

In the last two centuries, papers have been published including measurements of the germination process. High diversity of mathematical expressions has made comparisons between papers and some times the interpretation of results difficult. Thus, in this paper is included a review about measurements of the germination process, with an analysis of the several mathematical expressions included in the specific literature, recovering the history, sense, and limitations of some germination measurements. Among the measurements included in this paper are the germinability, germination time, coefficient of uniformity of germination (CUG), coefficient of variation of the germination time (CVt), germination rate (mean rate, weighted mean rate, coefficient of velocity, germination rate of George, Timson’s index, GV or Czabator’s index; Throneberry and Smith’s method and its adaptations, including Maguire’s rate; ERI or emergence rate index, germination index, and its modifications), uncertainty associated to the distribution of the relative frequency of germination (U), and synchronization index (Z). The limits of the germination measurements were included to make the interpretation and decisions during comparisons easier. Time, rate, homogeneity, and synchrony are aspects that can be measured, informing the dynamics of the germination process. These characteristics are important not only for physiologists and seed technologists, but also for ecologists because it is possible to predict the degree of successful of a species based on the capacity of their harvest seed to spread the germination through time, permitting the recruitment in the environment of some part of the seedlings formed.

Mathematical modeling of electro-rotation spectra of small particles in liquid solutions: Application to human erythrocyte aggregates

Electro-rotation can be used to determine the dielectric properties of cells, as well as to observe dynamic changes in both dielectric and morphological properties. Suspended biological cells and particles respond to alternating-field polarization by moving, deforming or rotating. While in linearly polarized alternating fields the particles are oriented along their axis of highest polarizability, in circularly polarized fields the axis of lowest polarizability aligns perpendicular to the plane of field rotation. Ellipsoidal models for cells are frequently applied, which include, beside sphere-shaped cells, also the limiting cases of rods and disks. Human erythrocyte cells, due to their particular shape, hardly resemble an ellipsoid. The additional effect of rouleaux formation with different numbers of aggregations suggests a model of circular cylinders of variable length. In the present study, the induced dipole moment of short cylinders was calculated and applied to rouleaux of human erythrocytes, which move freely in a suspending conductive medium under the effect of a rotating external field. Electro-rotation torque spectra are calculated for such aggregations of different length. Both the maximum rotation speeds and the peak frequencies of the torque are found to depend clearly on the size of the rouleaux. While the rotation speed grows with rouleaux length, the field frequency nup is lowest for the largest cell aggregations where the torque shows a maximum.

Community-based transconjunctival marginal rotation for cicatricial trachoma in Indians from the Upper Rio Negro basin

The objective of the present study was to describe, for the first time in Brazil, the use by a non-ophthalmologist of a community-based marginal rotation procedure by a posterior approach in the indigenous population from the Upper Rio Negro basin. Seventy-three upper eyelids of 46 Indians (11 males and 35 females) with cicatricial upper eyelid entropion and trichiasis were operated in the Indian communities using a marginal rotational procedure by a posterior approach by a non-ophthalmologist physician who had general surgery experience but only an extremely short period (one week) of ophthalmic training. Subjects were reevaluated 6 months after surgery. Results were classified according to the presence and location of residual trichiasis and symptoms were assessed according to a three-level subjective scale (better, worse or no change). Fifty-six eyelids (76.7%) were free from trichiasis, whereas residual trichiasis was observed in 17 eyelids (23.3%) of 10 subjects. In these cases, trichiasis was either lateral or medial to the central portion of the lid. Of these 10 patients, only 4 reported that the surgery did not improve the irritative symptoms. We conclude that marginal rotation by a posterior approach is an effective and simple procedure with few complications, even when performed by non-specialists. Due to its simplicity the posterior approach is an excellent option for community-based upper eyelid entropion surgery.

A semi-automatic computerized method to measure baroreflex-mediated heart rate responses that reduces interobserver variability

Arterial baroreflex sensitivity estimated by pharmacological impulse stimuli depends on intrinsic signal variability and usually a subjective choice of blood pressure (BP) and heart rate (HR) values. We propose a semi-automatic method to estimate cardiovascular reflex sensitivity to bolus infusions of phenylephrine and nitroprusside. Beat-to-beat BP and HR time series for male Wistar rats (N = 13) were obtained from the digitized signal (sample frequency = 2 kHz) and analyzed by the proposed method (PRM) developed in Matlab language. In the PRM, time series were low-pass filtered with zero-phase distortion (3rd order Butterworth used in the forward and reverse direction) and presented graphically, and parameters were selected interactively. Differences between basal mean values and peak BP (deltaBP) and HR (deltaHR) values after drug infusions were used to calculate baroreflex sensitivity indexes, defined as the deltaHR/deltaBP ratio. The PRM was compared to the method traditionally (TDM) employed by seven independent observers using files for reflex bradycardia (N = 43) and tachycardia (N = 61). Agreement was assessed by Bland and Altman plots. Dispersion among users, measured as the standard deviation, was higher for TDM for reflex bradycardia (0.60 ± 0.46 vs 0.21 ± 0.26 bpm/mmHg for PRM, P < 0.001) and tachycardia (0.83 ± 0.62 vs 0.28 ± 0.28 bpm/mmHg for PRM, P < 0.001). The advantage of the present method is related to its objectivity, since the routine automatically calculates the desired parameters according to previous software instructions. This is an objective, robust and easy-to-use tool for cardiovascular reflex studies.

Comparison of two questionnaires which measure the health-related quality of life of idiopathic pulmonary fibrosis patients

The objective of the present study was to determine if there is a health-related quality of life (HRQL) instrument, generic or specific, that better represents functional capacity dysfunction in idiopathic pulmonary fibrosis (IPF) patients. HRQL was evaluated in 20 IPF patients using generic and specific questionnaires (Medical Outcomes Short Form 36 (SF-36) and Saint George's Respiratory Questionnaire (SGRQ), respectively). Functional status was evaluated by pulmonary function tests, 6-min walking distance test (6MWDT) and dyspnea indexes (baseline dyspnea index) at rest and after exercise (modified Borg scale). There was a restrictive pattern with impairment of diffusion capacity (total lung capacity, TLC = 71.5 ± 15.6%, forced vital capacity = 70.4 ± 19.4%, and carbon monoxide diffusing capacity = 41.5 ± 16.2% of predicted value), a reduction in exercise capacity (6MWDT = 435.6 ± 95.5 m) and an increase of perceived dyspnea score at rest and during exercise (6 ± 2.5 and 7.1 ± 1.3, respectively). Both questionnaires presented correlation with some functional parameters (TLC, forced expiratory volume in 1 s and carbon monoxide diffusing capacity) and the best correlation was with TLC. Almost all of the SGRQ domains presented a strong correlation with functional status, while in SF-36 only physical function and vitality presented a good correlation with functional status. Dyspnea index at rest and 6MWDT also presented a good correlation with HRQL. Our results suggest that a specific instead of a generic questionnaire is a more appropriate instrument for HRQL evaluation in IPF patients and that TLC is the functional parameter showing best correlation with HRQL.

Mental rotation of anthropoid hands: a chronometric study

It has been shown that mental rotation of objects and human body parts is processed differently in the human brain. But what about body parts belonging to other primates? Does our brain process this information like any other object or does it instead maximize the structural similarities with our homologous body parts? We tried to answer this question by measuring the manual reaction time (MRT) of human participants discriminating the handedness of drawings representing the hands of four anthropoid primates (orangutan, chimpanzee, gorilla, and human). Twenty-four right-handed volunteers (13 males and 11 females) were instructed to judge the handedness of a hand drawing in palm view by pressing a left/right key. The orientation of hand drawings varied from 0º (fingers upwards) to 90º lateral (fingers pointing away from the midline), 180º (fingers downwards) and 90º medial (finger towards the midline). The results showed an effect of rotation angle (F(3, 69) = 19.57, P < 0.001), but not of hand identity, on MRTs. Moreover, for all hand drawings, a medial rotation elicited shorter MRTs than a lateral rotation (960 and 1169 ms, respectively, P < 0.05). This result has been previously observed for drawings of the human hand and related to biomechanical constraints of movement performance. Our findings indicate that anthropoid hands are essentially equivalent stimuli for handedness recognition. Since the task involves mentally simulating the posture and rotation of the hands, we wondered if "mirror neurons" could be involved in establishing the motor equivalence between the stimuli and the participants' own hands.

A novel procedure to measure the antioxidant capacity of Yerba maté extracts

Yerba maté extracts have in vitro antioxidant capacity attributed to the presence of polyphenolic compounds, mainly chlorogenic acids and dicaffeoylquinic acid derivatives. DPPH is one of the most used assays to measure the antioxidant capacity of pure compounds and plant extracts. It is difficult to compare the results between studies because this assay is applied in too many different conditions by the different research groups. Thus, in order to assess the antioxidant capacity of yerba maté extracts, the following procedure is proposed: 100 µL of an aqueous dilution of the extracts is mixed in duplicate with 3.0 mL of a DPPH 'work solution in absolute methanol (100 µM.L-1), with an incubation time of 120 minutes in darkness at 37 ± 1 °C, and then absorbance is read at 517 nm against absolute methanol. The results should be expressed as ascorbic acid equivalents or Trolox equivalents in mass percentage (g% dm, dry matter) in order to facilitate comparisons. The AOC of the ethanolic extracts ranged between 12.8 and 23.1 g TE % dm and from 9.1 to 16.4 g AAE % dm. The AOC determined by the DPPH assay proposed in the present study can be related to the total polyphenolic content determined by the Folin-Ciocalteu assay.

Application of exploratory factor analysis to assess fish consumption in a university community

The objective of this research was to use the technique of Exploratory Factor Analysis (EFA) for the adequacy of a tool for the assessment of fish consumption and the characteristics involved in this process. Data were collected during a campaign to encourage fish consumption in Brazil with the voluntarily participation of members of a university community. An assessment instrument consisting of multiple-choice questions and a five-point Likert scale was designed and used to measure the importance of certain attributes that influence the choice and consumption of fish. This study sample was composed of of 224 individuals, the majority were women (65.6%). With regard to the frequency of fish consumption, 37.67% of the volunteers interviewed said they consume the product two or three times a month, and 29.6% once a week. The Exploratory Factor Analysis (EFA) was used to group the variables; the extraction was made using the principal components and the rotation using the Quartimax method. The results show clusters in two main constructs, quality and consumption with Cronbach Alpha coefficients of 0.75 and 0.69, respectively, indicating good internal consistency.

Influence of temperate grass seed rotation systems on weed seed soil bank composition

Due to changing cropping practices in perennial grass seed crops in western Oregon, USA, alternative rotation systems are being considered to reduce weed infestations. Information is generally lacking regarding the effects of alternative agronomic operations and herbicide inputs on soil weed seed bank composition during this transition. Six crop rotation systems were imposed in 1992 on a field that had historically produced monoculture perennial ryegrass (Lolium perenne L.) seeds. Each system plot was 20 x 30 m, arranged in a randomized complete block design, replicated four times. Twenty to thirty soil cores were sampled in June 1997 from each plot. The weed species composition of the cores was determined by successive greenhouse grow-out assays. In addition to seed density, heterogeneity indices for species evenness, richness, and diversity were determined. The most abundant species were Juncus bufonius L. and Poa annua L. Changes in seed bank composition were due to the different herbicides used for the rotation crop components. Compared to the other rotation systems, no-tillage, spring-planted wheat (Triticum aestivum L.) and oat (Avena sativa L.) reduced overall weed seed density and richness, but did not affect weed species evenness or diversity. When meadowfoam (Limnanthes alba Hartweg ex Benth.) succeeded wheat in rotation, weed species richness was unaffected, but evenness and diversity were reduced, compared to the other rotation systems. For meadowfoam in sequence after white clover (Trifolium repens L.), crop establishment method (no-tillage and conventional tillage) had no effect on weed seed species density, evenness, or diversity.