1,279 research outputs found
Vertical distribution and trophic structure of the macrozooplankton in a shallow temperate estuary (Ria de Aveiro, Portugal)
The zooplankton of the lower part of Canal de Mira (Ria de Aveiro) was sampled during one lunar month. The sampling programme consisted of nine 25 hour fixed-cycles, separated weekly. In each cycle, samples were collected every two hours at three depths (surface, mid-water and above the bottom) with a 500 µm mesh net. The overall effect of the tidal phase was analyzed, taking into account the day and depth of the vertical position of the organisms through a 3-way analysis of variance (ANOVA). The zooplankton densities were, in general, higher at the surface during the night and near the bottom during the day, mainly at spring tide. The variation in the number of species followed a similar pattern to that observed for abundance. Significant differences (p<0.01) between diel and tidal phases were observed. Interaction between phase of the day and depth was also significant (p<0.05), with higher organism densities observed during night periods near the bottom. From a trophic point of view the zooplankton community of Canal de Mira was mainly composed of carnivorous and omnivorous species. Carnivores were significantly more abundant around the new and full moon (p<0.001), the omnivores at the new moon (p<0.001) and the herbivores and detritivores at the first quarter of the moon cycles (p<0.001). The density of carnivores was significantly higher at the surface at night and near the bottom during the day (p<0.05). Significant differences in the abundance of omnivores were observed between phases of the day and between depths, with higher values near the bottom during the day. The herbivores and detritivores had significantly higher densities during flood tides (p<0.001).DISTIBUICIÓN VERTICAL Y ESTRUCTURA TRÓFICA DEL MACROZOOPLANCTON EN UN ESTUARIO TEMPLADO (RIA DE
AVEIRO). – El zooplancton de la parte inferior del Canal de Mira (Ria de Aveiro) fue muestreado durante un mes lunar. El
programa de muestreo consistió en nueve ciclos de 25 horas, con periodicidad semanal. En cada ciclo, las muestras fueron
recogidas cada dos horas, a tres profundidades (superficie, columna de agua y sobre el fondo) con una red de 500 µm. El
efecto total de la fase de la marea fue analizado, teniendo en consideración el dÃa y la profundidad en la posición vertical de
los organismos con un análisis 3-Way ANOVA. Las densidades del zooplancton fueron en general más altas en la superficie
durante la noche y cercanas al fondo durante el dÃa, principalmente em la marea viva. La variación en el número de especies
siguió un patrón similar al observado para la abundancia. Se observaron diferencias significativas (p<0.01) entre las
fases del dÃa y las fases de marea. La interacción entre la fase del dÃa y la profundidad fue también significativa (p<0.05) con
densidades de organismos más altas durante los periodos nocturnos en el fondo. De un punto de vista trófico, la comunidad
zooplanctónica del Canal de Mira está principalmente compuesta por especies carnÃvoras y omnÃvoras. Los carnÃvoros fueram
significativamente más abundantes cerca de la luna nueva y de la luna llena (p<0.001), los omnÃvoros en la luna nueva
(p<0.001) y los herbÃvoros e detritÃvoros en el primero cuarto de los ciclos de la luna (p<0.001). La densidad de los carnÃ-
voros fue significativamente más alta en la superficie durante la noche y en el fondo durante el dÃa (p<0.05). Para los omnÃ-
voros, fueron observadas diferencias significativas entre las fases del dÃa y la profundidad, registando valores más elevados
en el fondo durante el dÃa. Los herbÃvoros y los detritÃvoros presentaron densidades significativamente superiores durante los
ciclos de marea (p<0.001)
Patterns of variation in the biochemical composition of Mesopodopsis slabberi (Van Beneden, 1861) (Crustacea: Mysidacea)
In order to assess the patterns of variation in the biochemical composition of Mesopodopsis slabberi (Van Beneden, 1861) in a temperate estuary, we determined the protein, carbohydrate, chitin and lipid contents of freshly caught immature individuals (juveniles), adult males, and adult females during two annual cycles. Statistical analysis (anova) revealed significant differences in the biochemical components between months and development stages for the months analysed. All of the biochemical components showed significant differences between months. Environmental and trophic conditions were the main processes determining seasonal patterns of variation in biochemical composition. The results of complementary experiments carried out to estimate the effects of starvation on biochemical composition showed that the process of starvation consumed mostly carbohydrates, and also that these compounds, together with lipids, were the most affected during the refeeding period. Our findings also indicate that all body reserves were almost fully replenished during refeeding, except for carbohydrates and lipids in adult females and immature individuals (juveniles) and protein content in immature individuals (juveniles). These results indicate that responses to fasting in M. slabberi may be dependent on individual development stages, an observation that is corroborated by the significant differences in the biochemical components observed between development stages for the months analysed. Reproduction was also found to influence patterns of variation in biochemical composition.Para evaluar los modelos de variación de la composición bioquÃmica de Mesopodopsis slabberi (Van Beneden, 1861) en un estuario templado, determinamos los contenidos en proteÃnas, hidratos de carbono, quitina y lÃpidos de individuos inmaduros (juveniles) recién cogidos, y de machos y hembras adultos, durante dos ciclos anuales. Los análisis estadÃsticos (anova) revelaron, para los meses analizados, diferencias significativas en las composiciones bioquÃmicas entre los meses y los estados de desarrollo. Todos los componentes bioquÃmicos mostraron diferencias significativas entre meses. Los factores ambientales y tróficos fueron los principales procesos que determinaron los modelos estacionales de variación en la composición bioquÃmica. Los resultados de los experimentos complementarios, realizados para determinar los efectos de la inanición sobre la composición bioquÃmica, pusieron de manifiesto que los procesos de inanición consumen, fundamentalmente, hidratos de carbono, y, también, que estos compuestos, junto con los lÃpidos, son los más afectados durante el periodo de vuelta a la alimentación. Nuestros descubrimientos indicaron también que todas las reservas corporales son casi completamente repuestas durante la vuelta a la alimentación, excepto los hidratos de carbono y los lÃpidos en las hembras adultas y en los inmaduros (juveniles), y el contenido en proteÃnas en los juveniles. Estos resultados indican que las respuestas al ayuno de M. slabberi podrÃan depender del estado de desarrollo individual, observación que es corroborada por las diferencias significativas observadas, en los componentes bioquÃmicos y para los meses analizados, entre los distintos estados de desarrollo. Se encontró también que la reproducción tenÃa influencia sobre los modelos de variación de la composición bioquÃmica.Instituto Español de OceanografÃ
On exact time-averages of a massive Poisson particle
In this work we study, under the Stratonovich definition, the problem of the
damped oscillatory massive particle subject to a heterogeneous Poisson noise
characterised by a rate of events, \lambda (t), and a magnitude, \Phi,
following an exponential distribution. We tackle the problem by performing
exact time-averages over the noise in a similar way to previous works analysing
the problem of the Brownian particle. From this procedure we obtain the
long-term equilibrium distributions of position and velocity as well as
analytical asymptotic expressions for the injection and dissipation of energy
terms. Considerations on the emergence of stochastic resonance in this type of
system are also set forth.Comment: 21 pages, 5 figures. To be published in Journal of Statistical
Mechanics: Theory and Experimen
Traumatic experiences in a lifetime: impact on the connection with others and the role of emotions
Abstract in proceedings of the Fourth International Congress of CiiEM: Health, Well-Being and Ageing in the 21st Century, held at Egas Moniz’ University Campus in Monte de Caparica, Almada, from 3–5 June 2019.This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.info:eu-repo/semantics/publishedVersio
PERCUTANEOUS KIDNEY BIOPSY: eight years-experience
A biópsia renal constitui um instrumento fundamental para o diagnóstico e prognóstico
de diversas patologias nefrológicas e sistémicas. No nosso Hospital a sua realização
iniciou-se em 1994, tendo sido biopsado um doente com Doença de Berger.
Até à data foram efectuadas 91 biópsias renais percutâneas com a seguinte distribuição
anual: 1994 (n=3), 1995 (n=3), 1996 (n=3), 1997 (n=15), 1998 (n=5), 1999 (n=23), 2000
(n=13), 2001 (n=26) em 57 homens e 34 mulheres.
Foi utilizada orientação ecográfica e na maioria dos casos a agulha de Vim Silverman
(14G). Apenas em cinco casos se utilizou uma pistola automática BARD. Era nosso
objectivo, em cada biópsia, a colheita de pelo menos dois fragmentos, um para microscopia
óptica e outro para imunoflurescência.
Os grandes sÃndromas nefrológicos que conduziram a este exame foram: sÃndroma
nefrótico (n=27), anormalidades urinárias assintomáticas (n=25), insuficiência renal aguda
ou rápidamente progressiva (n=18), insuficiência renal crónica (n=15), hipertensão arterial
(n=4) e glomerulonefrite aguda (n=2).
Em 92.3% (84/91) dos casos foi possÃvel efectuar um diagnóstico histológico por
microscopia óptica. Se considerarmos, no entanto, sete casos com suspeita clÃnica de
nefropatia IgA em que o fragmento colhido para imunoflurescência não continha
glomérulos, a eficácia diminuiu para 84.6% (77/91). O número médio de glomérulos por
amostra foi de 18.3 ± 14.2 [0-80].
Os diagnósticos histológico obtidos foram os seguintes: doença de Berger (n=24),
diversas formas de sÃndroma nefrótico primário (n=18), nefrite lúpica (n=8),
glomerulonefrite mesangioproliferativa, sem glomérulos na imunoflurescência (n=6),
ausência de tecido renal ou de glomérulos nas amostras (n=6), sÃndroma nefrótico
secundário (n=4), nefrite túbulo-intersticial ou necrose tubular aguda (n=4), nefropatia
diabética (n=3), rim de mieloma (n=3), glomerulonefrite crescêntica sem depósitos imunes
(n=3), nefroangiosclerose hipertensiva (n=2), glomerulonefrite mesangioproliferativa
IgM (n=2) e outros (n=8).
A hematúria macroscópica revelou-se como a complicação mais frequente (n=9; 9.9%).
Apenas em três casos se verificou a existência de hematoma renal ecograficamente
(3.3%). A saÃda de sangue pelo mandril da agulha de biópsia surgiu em quatro casos
(4.4%) e foi necessário proceder à transfusão de concentrado de glóbulos rubros em
três doentes (3.3%). Registamos uma punção acidental de baço. Em nenhum caso foi
necessário efectuar nefrectomia por hemorragia incontrolável.
Identificamos, como Ãndices de mau prognóstico relativamente à evolução para
insuficiência renal crónica avançada (n=2) ou terminal (n=15), o maior número de
glomérulos esclerosados (30% vs 8%; p<0.01) e de lesões túbulo-intersticiais (100% vs
63%; p<0.01).
Em conclusão, a biópsia renal efectuada com orientação ecográfica permitiu a obtenção
21
de amostras com valor diagnóstico em 84.6% dos casos. A taxa de complicações foi
relativamente baixa comparando com outras séries. Verificamos um progressivo aumento
de qualidade das amostras renais colhidas, em relação directa com uma coordenação
técnica crescente entre os nefrologistas e radiologistas intervenientes.nephrological and systemic pathologies. At our institution the first patient submitted to
this technique, at 1994, showed Berger disease.
Until 2002 we have performed 91 renal biopsies (57 men and 34 women) with the following
annual distribution: 1994 (n=3), 1995 (n=3), 1996 (n=3), 1997 (n=15), 1998 (n=5), 1999
(n=23), 2000 (n=13) and 2001 (n=26).
Ultrasound guidance was always used and in most of cases the technique was performed
with Vim-Silverman (14G) needle. BARD automatic system was employed in only five
patients.
The clinical diagnosis that lead to renal biopsy were: nephrotic syndrome (n=27),
asyntomatic urinary abnormalities (n=25), acute or rapidly progressive renal failure (n=18),
chronic renal failure (n=15), hypertension (n=4) and acute nephritis (n=2).
The efficacy for optic histological diagnosis was 92.3% (84/91). However, if we include
seven cases of presumed IgA nephropathy that don’t included fragment for
immunofluorescence (IF) analysis the efficacy declined to 84.6% (77/91). The mean
number of glomeruli per fragment was 18.3 ± 14.2 [0-80].
Histological diagnosis were the following: Berger disease (n=24), idiopathic nephrotic
syndrome (n=18), lupus nephritis (n=8), mesangial proliferative glomerulonephritis
without glomeruli in the IF fragment (n=6), without glomeruli (n=6), secondary nephrotic
syndrome (n=4), tubulointerstitial nephritis or acute tubular necrosis (n=4), diabetic
nephropathy (n=3), myeloma kidney (n=3), pauci-imune and crescentic
glomerulonephritis (n=3), hypertensive nephropathy (n=2), IgM mesangial proliferative
glomerulonephritis (n=2) and various (n=8).
Gross hematuria appeared in 9 patients (9.9%). Only in three of these patients it was
showed, by ecography, the existence of kidney haematoma. Bleeding throughout the
mandrill in four cases, leaded to transfusion in only three patients. We have registered
one accidental spleen puncture. Nephrectomy for incontrollable bleeding was never
needed.
Higher glomerulosclerosis (30% vs 8%; p<0.01) and also a greater extent of
tubulointersticial lesions (100% vs 63%; p<0.01), were predictors of progression into
end-stage or advanced renal failure.
Concluding, renal biopsy with ultrasound guidance was valuable for diagnosis in 84.6%
of our proceedings. Our serie is similar to others concerning serious complications.
Nephrologists and radiologists improved progressively their coordination performing
this technique, improving the results during this period of 8 years
Contribution of biological nitrogen fixation to cowpeas: a strategy for improving grain yield in the semi-árid region of Brazil.
Nodulating bacteria from the famaly Rhizobiaceae are common in the semi-arid tropics around the world. The brazilian semi-arid region extends over 95 million hectares of which only 3% is suitable for irrigation, therefore leaving an immense dryland area to be exploited by peasant farmers, who often lack appropriate technologies for sustainable management. Cowpea is an impoertant crop in this area, representing the staple protein source for human nutrition. This work aimed to identify rhizobial strains capable of guaranteeint sufficient nitrogen derived from biological fixation fpr cowpea cultivated in dryland areas, evaluating not just efficiecy but also the ecological parameters of competitiveness and survival in the soil. Grain yield and nodulation parameters showed that strain BR 3267 is capable of stablishing efficient nodulation, improving both yield and total N accumulated in grain. Cowpea inoculated with strain BR 3267 showed grain productivity similar to plants receiving 50 kg of N per hectare, which is the amount of fertilizer commonly used in the North-east region. These characteristics associated with previously determined ecological properties makes strain BR 3267 an important resource for the optimization of biological nitrogen fixation in cowpea in the dryland areas of the semi-arid tropics. Data on the dynamics of rhizzobizl populations in such areas have shown that (1) the naturalized rhizobium population is very small and, by themselves, do not promote proper nodulation and, (2) the inoculant rhizobia do not persist between crops. Such characteristics represent an opportunity for the introduction of superior rizhobia strains, such as BR 3267, during the cowpea crop
Self-diffusion in granular gases
The coefficient of self-diffusion for a homogeneously cooling granular gas
changes significantly if the impact-velocity dependence of the restitution
coefficient is taken into account. For the case of a constant
the particles spread logarithmically slow with time, whereas the
velocity dependent coefficient yields a power law time-dependence. The impact
of the difference in these time dependences on the properties of a freely
cooling granular gas is discussed.Comment: 6 pages, no figure
Recommended from our members
The application of a microstrip gas counter to energy-dispersive x-ray fluorescence analysis
Performance characteristics of a microstrip gas counter operated as a x-ray fluorescence spectrometer are reported. Gas amplification as a function of microstrip anode-cathode voltage was measured, and the breakdown threshold voltage was determined in pure xenon. The detector temporal stability and the effect of gas purity were assessed. Energy resolution and linearity, detection efficiency, and uniformity of spatial response in the 2- to 60-keV x-ray energy range were determined from the pulse-height distributions of the fluorescence x-ray spectra induced in a variety of single- and multi-element sample materials. Energy resolution similar to conventional proportional counters was achieved at 6 keV
Unifying Reasoning and Core-Guided Search for Maximum Satisfiability
A central algorithmic paradigm in maximum satisfiability solving geared towards real-world optimization problems is the core-guided approach. Furthermore, recent progress on preprocessing techniques is bringing in additional reasoning techniques to MaxSAT solving. Towards realizing their combined potential, understanding formal underpinnings of interleavings of preprocessing-style reasoning and core-guided algorithms is important. It turns out that earlier proposed notions for establishing correctness of core-guided algorithms and preprocessing, respectively, are not enough for capturing correctness of interleavings of the techniques. We provide an in-depth analysis of these and related MaxSAT instance transformations, and propose correction set reducibility as a notion that captures inprocessing MaxSAT solving within a state-transition style abstract MaxSAT solving framework. Furthermore, we establish a general theorem of correctness for applications of SAT-based preprocessing techniques in MaxSAT. The results pave way for generic techniques for arguing about the formal correctness of MaxSAT algorithms.Peer reviewe
Perfluoropolyethers: Development of an All-Atom Force Field for Molecular Simulations and Validation with New Experimental Vapor Pressures and Liquid Densities
A force field for perfluoropolyethers (PFPEs) based on the
general optimized potentials for liquid simulations all-atom (OPLS-AA) force
field has been derived in conjunction with experiments and ab initio quantum
mechanical calculations. Vapor pressures and densities of two liquid PFPEs,
perfluorodiglyme (CF3−O−(CF2−CF2−O)2−CF3) and perfluorotriglyme
(CF3−O−(CF2−CF2−O)3−CF3), have been measured experimentally to
validate the force field and increase our understanding of the physical
properties of PFPEs. Force field parameters build upon those for related
molecules (e.g., ethers and perfluoroalkanes) in the OPLS-AA force field, with
new parameters introduced for interactions specific to PFPEs. Molecular
dynamics simulations using the new force field demonstrate excellent
agreement with ab initio calculations at the RHF/6-31G* level for gas-phase
torsional energies (<0.5 kcal mol−1 error) and molecular structures for several
PFPEs, and also accurately reproduce experimentally determined densities (<0.02 g cm−3 error) and enthalpies of vaporization
derived from experimental vapor pressures (<0.3 kcal mol−1). Additional comparisons between experiment and simulation show
that polyethers demonstrate a significant decrease in enthalpy of vaporization upon fluorination unlike related molecules (e.g.,
alkanes and alcohols). Simulation suggests this phenomenon is a result of reduced cohesion in liquid PFPEs due to a reduction in
localized associations between backbone oxygen atoms and neighboring molecules
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